TY - JOUR AB - Cold-triggered adaptation of the brown adipose tissue (BAT) promotes increased non-shivering thermogenesis and helps maintain body temperature. Here, we demonstrate that the secreted protein developmental endothelial locus-1 (DEL-1) acts as a regulator of cold-induced BAT adaptation. DEL-1 was expressed in the vascular endothelium of the BAT and its expression was upregulated upon cold exposure. By interacting with αvβ3 integrin on brown adipocyte progenitor cells, DEL-1 promoted their proliferation in a manner dependent on AKT signaling and glycolysis activation. Compared to DEL-1-sufficient mice, DEL-1-deficient mice or mice expressing a non-integrin-binding mutant of DEL-1 carrying an Asp-to-Glu substitution in its RGD motif, displayed decreased cold tolerance. This phenotype was associated with impaired BAT adaptation to cold and reduced brown adipocyte progenitor cell proliferation. Conversely, endothelial-specific DEL-1 overexpression in DEL-1-deficient mice restored the BAT thermogenic response to cold. Together, the DEL-1/αvβ3 integrin-dependent endothelial-brown adipocyte progenitor cell crosstalk promotes cold-stimulated BAT adaptation. This knowledge could be potentially harnessed therapeutically for promoting BAT expansion towards improving systemic metabolism. AU - Chung, K.J.* AU - Chatzigeorgiou, A.* AU - Lim, J.H.* AU - Li, X.* AU - Marava, I.* AU - Kim, D.Y.* AU - Witt, A.* AU - Gebler, J.* AU - Grossklaus, S.* AU - Gercken, B.* AU - Kopaliani, I.* AU - Subramanian, P.* AU - Blüher, M. AU - Bdeir, K.* AU - Alexaki, V.I.* AU - Hajishengallis, G.* AU - Chavakis, T. C1 - 75299 C2 - 58261 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - A DEL-1/αvβ3 integrin axis promotes brown adipocyte progenitor proliferation and cold-induced brown adipose tissue adaptation. JO - Mol. Metab. VL - 100 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - Recent modifications to glucagon-like peptide 1 (GLP-1), known for its insulinotropic and satiety-inducing effects, have focused on conjugating small molecules to enable selective delivery into GLP-1R+ tissues to achieve targeted synergy and improved metabolic outcomes. Despite continued advancements in GLP-1/small molecule conjugate strategies, the intracellular mechanisms facilitating concurrent GLP-1R signaling and small molecule cargo release remain poorly understood. We evaluate an estradiol (E2)-conjugated GLP-1 (GLP-1-CEX/E2) for relative differences in GLP-1R signaling and trafficking, and elucidate endolysosomal dynamics that lead to estrogenic activity using various live-cell, reporter, imaging, and mass-spectrometry techniques. We find GLP-1-CEX/E2 does not differentially activate or traffic the GLP-1R relative to its unconjugated GLP-1 backbone (GLP-1-CEX), but uniquely internalizes the E2 moiety and stimulates estrogenic signaling. Endolysosomal pH-dependent proteolytic activity likely mediates E2 moiety liberation, as evidenced by clear amplification in estrogenic activity following co-administration with lysosomal VATPase activator EN6. The hypothesized liberated metabolite from GLP-1-CEX/E2, E2-3-ether, exhibits partial estrogenic efficacy through ERα, and is predisposed toward estrone-3-sulfate conversion. Finally, we identify relative increases in intracellular E2, estrone, and estrone-3-sulfate following GLP-1-CEX/E2 incubation in GLP-1R+ cells, demonstrating proof-of-principle for desired cargo release. Together, our data suggest that GLP-1-CEX/E2 depends on GLP-1R trafficking and lysosome acidification for estrogenic efficacy, with a likely conversion of the liberated E2-3-ether metabolite into estrone-3-sulfate, resulting in residual downstream flux into active estradiol. Our current findings aim to improve the understanding of small molecule targeting and the efficacy behind GLP-1/small molecule conjugates. AU - Coupland, C. AU - Sun, N. AU - Khalil, A. AU - Karaoglu, Ö.E. AU - Liskiewicz, A. AU - Liskiewicz, D. AU - Grandl, G. AU - Akindehin, S.E. AU - Maity-Kumar, G. AU - Yang, B.* AU - Finan, B.* AU - Knerr, P.J.* AU - Douros, J.D.* AU - Walch, A.K. AU - DiMarchi, R.* AU - Tschöp, M.H. AU - Müller, T.D. AU - Novikoff, A. C1 - 74045 C2 - 57308 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Estrogenic activity of E2-conjugated GLP-1 is mediated by intracellular endolysosomal acidification and estrone metabolism. JO - Mol. Metab. VL - 96 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) agonism is foundational to modern obesity pharmacotherapies. These compounds were engineered for maximal G protein alpha(s) (Gsα) signaling potency and downstream cAMP production. However, this strategy requires reconsideration as partial, biased GLP-1R agonists characterized by decreased Gsα signaling and disproportionate reductions in β-arrestin recruitment relative to the native ligand provide greater weight loss than full, balanced agonists in preclinical models. METHODS: We tested the hypothesis that in vitro signaling bias, which considers both cAMP signaling and β-arrestin recruitment, better predicts weight loss efficacy in diet induced obese (DIO) rodents than cAMP potency alone. RESULTS: Our data demonstrate that signaling bias significantly correlates to GLP-1R agonist mediated weight loss in diet-induced obese mice. We further characterized a protracted GLP-1 analogue (NNC5840) which exhibits a partial-Gsα, cAMP-biased GLP-1R signaling profile in vitro and demonstrates superior maximal body weight reduction compared to semaglutide in DIO mice. The NNC5840 weight loss profile is characterized by reduced in vivo potency but increased maximal efficacy. CONCLUSION: The data demonstrate that biased agonism is a strong predictor of in vivo efficacy for GLP-1R agonists independent of factors like intrinsic cAMP potency or pharmacokinetics. These data suggest that drug discovery screening strategies which take a holistic approach to target receptor signaling may provide more efficacious candidate molecules. The interpretations of these studies are limited by unknowns including how structural modifications to the biased GLP-1R agonist effect physiochemical properties of the molecules. AU - Douros, J.D.* AU - Novikoff, A. AU - Dubois, B.* AU - Rohlfs, R.* AU - Mokrosiński, J.* AU - Hogendorf, W.F.J.* AU - Augustin, R.* AU - Merkestein, M.* AU - Egaa Martini, L.B.* AU - Linderoth, L.* AU - Gerrard, E.* AU - Kodra, J.T.* AU - Norlin, J.* AU - Roed, N.K.* AU - Oldenburger, A.* AU - Mowery, S.A.* AU - Waldhoer, M.* AU - Perez-Tilve, D.* AU - Finan, B.* AU - Reedtz-Runge, S.* AU - Müller, T.D. AU - Knerr, P.J.* C1 - 73802 C2 - 57236 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - A GLP-1 analogue optimized for cAMP-biased signaling improves weight loss in obese mice. JO - Mol. Metab. VL - 100 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - Endurance exercise reduces the risk of metabolic diseases by improving skeletal muscle metabolism, particularly in individuals with overweight and obesity. As biological sex impacts glucose and fatty acid handling in skeletal muscle, we hypothesized sex differences at the transcriptomic and proteomic level in the acute response to exercise and after an 8-week exercise intervention. We analyzed skeletal muscle biopsies from 25 sedentary subjects (16f/9m) with overweight and obesity using transcriptomics and proteomics at baseline, after acute exercise, and following an 8-week endurance training program. Regulation of sex-specific differences was studied in primary myotubes from the donors. At baseline, differentially methylated CpG-sites potentially explain up to 59% of transcriptomic and 67% of proteomic sex differences. Differences were dominated by higher abundance of fast-twitch fiber type proteins, and transcripts and proteins regulating glycogen degradation and glycolysis in males. Females showed higher abundance of proteins regulating fatty acid uptake and storage. Acute exercise induced stress-responsive transcripts and serum myoglobin predominantly in males. Both sexes adapted to 8-week endurance training by upregulating mitochondrial proteins involved in TCA cycle, oxidative phosphorylation, and β-oxidation. Training equalized fast-twitch fiber type protein levels, mainly by reducing them in males. In vivo sex differences in autosomal genes were poorly retained in myotubes but partially restored by sex hormone treatment. In conclusion, our findings highlight sex-specific molecular signatures that reflect known differences in glucose and lipid metabolism between female and male skeletal muscle. After just 8 weeks of endurance training, these sex differences were attenuated, suggesting a convergence towards a shared beneficial adaptation at the molecular level. AU - Dreher, S.I.* AU - Goj, T. AU - von Toerne, C. AU - Hoene, M.* AU - Irmler, M. AU - Ouni, M.* AU - Jähnert, M.* AU - Beckers, J. AU - Hrabě de Angelis, M. AU - Peter, A. AU - Moller, A. AU - Birkenfeld, A.L. AU - Schürmann, A.* AU - Hauck, S.M. AU - Weigert, C. C1 - 74932 C2 - 57678 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Sex differences in resting skeletal muscle and the acute and long-term response to endurance exercise in individuals with overweight and obesity. JO - Mol. Metab. VL - 98 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - Single molecules that combine complementary modes of action with glucagon-like peptide-1 receptor (GLP-1R) agonism are best-in-class therapeutics for obesity treatment. NN1706 (MAR423, RO6883746) is a fatty-acylated tri-agonist designed for balanced activity at GLP-1R and glucose-dependent insulinotropic polypeptide receptor (GIPR) with lower relative potency at the glucagon receptor (GcgR). Obese mice, rats and non-human primates dosed with NN1706 showed significant body weight reductions and improved glycemic control. In human participants with overweight or obesity, daily subcutaneous NN1706 treatment resulted in substantial body weight loss in a dose-dependent manner without impairing glycemic control (NCT03095807, NCT03661879). However, increased heart rate was observed across NN1706 treatment cohorts, which challenges further clinical development of NN1706. AU - Finan, B.* AU - Douros, J.D.* AU - Goldwater, R.* AU - Hansen, A.M.K.* AU - Hjerpsted, J.B.* AU - Hjøllund, K.R.* AU - Kankam, M.K.* AU - Knerr, P.J.* AU - Konkar, A.* AU - Mowery, S.A.* AU - Müller, T.D. AU - Nielsen, J.R.* AU - Nygård, S.B.* AU - Perez-Tilve, D.* AU - Raun, K.* AU - Yang, B.* AU - Tschöp, M.H. AU - DiMarchi, R.D.* C1 - 73786 C2 - 57222 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - A once-daily GLP-1/GIP/glucagon receptor tri-agonist (NN1706) lowers body weight in rodents, monkeys and humans. JO - Mol. Metab. VL - 96 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - BACKGROUND AND AIMS: Fasting hypoglycemia has clinical implications for children with growth hormone (GH)-insensitivity syndrome. This study investigates the pathophysiology of juvenile hypoglycemia in a large animal model for GH receptor (GHR) deficiency (the GHR-KO pig) and elucidates mechanisms underlying the transition to normoglycemia in adulthood. METHODS: Insulin sensitivity was assessed in juvenile and adult GHR-KO pigs and wild-type (WT) controls via hyperinsulinemic-euglycemic clamp (HEC) tests. Glucose turnover was measured using D-[6,6-2H2] glucose and 2H2O. Clinical chemical and targeted metabolomics parameters in blood serum were correlated with qPCR and western blot analyses of liver and adipose tissue. RESULTS: GHR-KO pigs showed increased insulin sensitivity (p=0.0019), especially at young age (M-value +34% vs. WT), insignificantly reduced insulin levels, and reduced endogenous glucose production (p=0.0007), leading to fasting hypoglycemia with depleted liver glycogen, elevated β-hydroxybutyrate, but no increase in NEFA levels. Low hormone-sensitive lipase phosphorylation in adipose tissue suggested impaired lipolysis in young GHR-KO pigs. Metabolomics indicated enhanced fatty acid beta-oxidation and use of glucogenic amino acids, likely serving as compensatory pathways to maintain energy homeostasis. In adulthood, insulin sensitivity remained elevated but less pronounced (M-value +20%), while insulin levels were significantly reduced, enabling normoglycemia and improved NEFA availability. Increased fat mass, not sex hormones, appeared key to this metabolic transition, as early castration had no effect. CONCLUSION: Juvenile hypoglycemia in GH insensitivity results from excessive insulin sensitivity, reduced glucose production, and impaired lipolysis. Normoglycemia in adulthood emerges through increased adiposity and moderated insulin sensitivity, independently of sex hormones. These findings elucidate the age-dependent metabolic adaptations in GH insensitivity. AU - Hinrichs, A.* AU - Pafili, K.* AU - Sancar, G. AU - Laane, L.* AU - Zettler, S.* AU - Torgeman, M.* AU - Kessler, B.* AU - Nono, J.L. AU - Kunz, S.* AU - Rathkolb, B. AU - Barosa, C.* AU - Prehn, C. AU - Cecil, A. AU - Renner, S.* AU - Kemter, E.* AU - Kahl, S.* AU - Szendroedi, J. AU - Bidlingmaier, M.* AU - Jones, J.G.* AU - Hrabě de Angelis, M. AU - Roden, M.* AU - Wolf, E.* C1 - 75839 C2 - 58136 TI - Transient juvenile hypoglycemia in GH insensitive Laron syndrome pigs is associated with insulin hypersensitivity. JO - Mol. Metab. PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - BACKGROUND: In autoimmune Type 1 Diabetes (T1D), aberrant immune activation promotes regulatory T cell (Treg) impairments thereby boosting progression of islet autoimmunity. Consequently, there is a progressive destruction of the insulin-producing beta cells in the pancreas. Controlling overshooting immune activation represents a relevant approach to allow for efficient Treg-targeting by broadening the window of opportunity to induce Tregs. METHODS: We investigated the effect of restricting pyrimidine de novo synthesis during islet autoimmunity and T1D by Dihydroorotate dehydrogenase (DHODH) inhibition using the next-generation DHODH inhibitor Vidofludimus calcium. We assessed Treg-inducing features of DHODH inhibition in T cells from ongoing murine islet autoimmunity and human T1D in vitro. To dissect the functional relevance of these observations, we tested the impact of DHODH inhibition on interfering with autoimmune activation and disease progression in pre-clinical models of T1D in vivo. MAIN FINDINGS: We show that DHODH inhibition results in enhanced Treg induction in vitro especially during increased immune activation and reduced T cell proliferation. In addition, Vidofludimus calcium reduced T1D incidence in two mouse models. On the cellular level, treated mice showed reduced T cell activation accompanied by increased Treg frequencies. CONCLUSIONS: We demonstrate that restricting pyrimidine de novo synthesis by next-generation DHODH inhibition is a strategy to interfere with autoimmune activation while fostering Tregs. AU - Hipp, H. AU - Tondello, C. AU - Gmehling, H. AU - Scholz, L.K.* AU - Stavridou, A.* AU - Becker, M. AU - Bührer, A.-M. AU - Hintermann, E.* AU - Dirschl, S.M. AU - Johannsmann, T.M. AU - Scherm, M.G. AU - Kohlhof, H.* AU - Serr, I. AU - Christen, U.* AU - Daniel, C. C1 - 75240 C2 - 57869 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Inhibition of pyrimidine de novo synthesis fosters Treg cells and reduces diabetes development in models of Type 1 Diabetes. JO - Mol. Metab. VL - 100 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - Infiltration of adipocytes into the pancreatic parenchyma has been linked to impaired insulin secretion in individuals with increased genetic risk of T2D and prediabetic conditions. However, the study of this ectopic fat depot has been limited by the lack of suitable in vitro models. Here, we developed a novel 3D model of functionally mature human pancreatic adipose tissue organoids by aggregating human pancreatic adipose tissue-derived stromal vascular fraction (SVF) cells into organoids and differentiating them over 19 days. These organoids carry biological properties of the in situ pancreatic fat, presenting levels of adipogenic markers comparable to native pancreatic adipocytes and improved lipolytic and anti-lipolytic response compared to conventional 2D cultures. The organoids harbour a small population of immune cells, mimicking in vivo adipose environment. Furthermore, they express GIPR, allowing investigation of incretin effects in pancreatic fat. In accordance, GIP and the dual GLP1R/GIPR agonist tirzepatide stimulate lipolysis but had distinct effects on the expression of proinflammatory cytokines. This novel adipose organoid model is a valuable tool to study the metabolic impact of incretin signalling in pancreatic adipose tissue, revealing potential therapeutic targets of incretins beyond islets. The donor-specific metabolic memory of these organoids enables examination of the pancreatic fat-islet crosstalk in a donor-related metabolic context. AU - Lorza-Gil, E. AU - Strauss, O.* AU - Ziegler, E.* AU - Kansy, K.* AU - Katschke, M.-T. AU - Rahimi, G.* AU - Neuscheler, D.* AU - Sandforth, L. AU - Sandforth, A. AU - Sancar, G. AU - Kaufmann, B.* AU - Hartmann, D.* AU - Singer, S.R.* AU - Mihaljevic, A.L.* AU - Jumpertz von Schwartzenberg, R. AU - Sbierski-Kind, J. AU - Müller, T.D. AU - Birkenfeld, A.L. AU - Gerst, F. C1 - 72386 C2 - 56607 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Incretin-responsive human pancreatic adipose tissue organoids: A functional model for fatty pancreas research. JO - Mol. Metab. VL - 91 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - BACKGROUND: Glucose-dependent insulinotropic polypeptide (GIP) was the first incretin identified and plays an essential role in the maintenance of glucose tolerance in healthy humans. Until recently GIP had not been developed as a therapeutic and thus has been overshadowed by the other incretin, glucagon-like peptide 1 (GLP-1), which is the basis for several successful drugs to treat diabetes and obesity. However, there has been a rekindling of interest in GIP biology in recent years, in great part due to pharmacology demonstrating that both GIPR agonism and antagonism may be beneficial in treating obesity and diabetes. This apparent paradox has reinvigorated the field, led to new lines of investigation, and deeper understanding of GIP. SCOPE OF REVIEW: In this review, we provide a detailed overview on the multifaceted nature of GIP biology and discuss the therapeutic implications of GIPR signal modification on various diseases. MAJOR CONCLUSIONS: Following its classification as an incretin hormone, GIP has emerged as a pleiotropic hormone with a variety of metabolic effects outside the endocrine pancreas. The numerous beneficial effects of GIPR signal modification render the peptide an interesting candidate for the development of pharmacotherapies to treat obesity, diabetes, drug-induced nausea and both bone and neurodegenerative disorders. AU - Müller, T.D. AU - Adriaenssens, A.* AU - Ahrén, B.* AU - Blüher, M. AU - Birkenfeld, A.L. AU - Campbell, J.E.* AU - Coghlan, M.P.* AU - D'Alessio, D.* AU - Deacon, C.F.* AU - DelPrato, S.* AU - Douros, J.D.* AU - Drucker, D.J.* AU - Figueredo Burgos, N.S.* AU - Flatt, P.R.* AU - Finan, B.* AU - Gimeno, R.E.* AU - Gribble, F.M.* AU - Hayes, M.R.* AU - Hölscher, C.* AU - Holst, J.J.* AU - Knerr, P.J.* AU - Knop, F.K.* AU - Kusminski, C.M.* AU - Liskiewicz, A. AU - Mabilleau, G.* AU - Mowery, S.A.* AU - Nauck, M.A.* AU - Novikoff, A. AU - Reimann, F.* AU - Roberts, A.G.* AU - Rosenkilde, M.M.* AU - Samms, R.J.* AU - Scherer, P.E.* AU - Seeley, R.J.* AU - Sloop, K.W.* AU - Wolfrum, C.* AU - Wootten, D.* AU - DiMarchi, R.D.* AU - Tschöp, M.H. C1 - 73575 C2 - 57110 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Glucose-dependent insulinotropic polypeptide (GIP). JO - Mol. Metab. VL - 95 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - BACKGROUND: Cellular senescence (CS) is a key aging process that leads to irreversible cell cycle arrest and an altered secretory phenotype. In skeletal muscle (SkM), the accumulation of senescent cells contributes to sarcopenia. Despite exercise being a known intervention for maintaining SkM function and metabolic health, its effects on CS remain poorly understood. OBJECTIVES: This study aimed to investigate the impact of exercise on CS in human SkM by analyzing muscle biopsies from young, normal-weight individuals and middle-aged individuals with obesity, both before and after exercise intervention. METHODS: Muscle biopsies were collected from both groups before and after an exercise intervention. CS markers, insulin sensitivity (measured with euglycemic clamp), and satellite cell markers were analyzed. Additionally, in vitro experiments were conducted to evaluate the effects of cellular senescence on human satellite cells, focusing on key regulatory genes and insulin signaling. RESULTS: Individuals with obesity showed significantly elevated CS markers, along with reduced expression of GLUT4 and PAX7, indicating impaired insulin action and regenerative potential. Exercise improved insulin sensitivity, reduced CS markers, and activated satellite cell response in both groups. In vitro experiments revealed that senescence downregulated key regulatory genes in satellite cells and impaired insulin signaling by reducing the Insulin Receptor β-subunit. CONCLUSIONS: These findings highlight the role of CS in regulating insulin sensitivity in SkM and underscore the therapeutic potential of exercise in mitigating age- and obesity-related muscle dysfunction. Targeting CS through exercise or senolytic agents could offer a promising strategy for improving metabolic health and combating sarcopenia, particularly in at-risk populations. AU - Podraza-Farhanieh, A.* AU - Spinelli, R.* AU - Zatterale, F.* AU - Nerstedt, A.* AU - Gogg, S.* AU - Blüher, M. AU - Smith, U.* C1 - 73748 C2 - 57213 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Physical training reduces cell senescence and associated insulin resistance in skeletal muscle. JO - Mol. Metab. VL - 95 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - Parkinson's disease (PD) is recognized as a systemic condition, with clinical features potentially modifiable by dietary intervention. Diets high in saturated fats and refined sugars significantly increase PD risk and exacerbate motor and non-motor symptoms, yet precise metabolic mechanisms are unclear. To investigate the interplay between diet and PD, we used a model of early-onset PD under chronic glycative stress induced by prolonged high-fat high-sucrose (HFHS) diet. We found this obesogenic diet drives loss of fat and muscle mass in early-onset PD mice, with a selective vulnerability of glycolytic myofibers. We show that PD mice and early-onset familial PD patients are under pervasive glycative stress with pathological accumulation of advanced glycation end products (AGEs), including two previously unknown glycerinyl-AGE markers. AU - Prudente de Mello, N. AU - Berger, M. AU - Lagerborg, K.A.* AU - Yan, Y. AU - Wettmarshausen, J. AU - Keipert, S.* AU - Weidner, L. AU - Tokarz, J. AU - Möller, G. AU - Ciciliot, S.* AU - Walia, S.R. AU - Cheng, Y. AU - Chudenkova, M. AU - Artati, A. AU - Weisenhorn, D.M. AU - Wurst, W. AU - Adamski, J. AU - Nilsson, R.H.* AU - Cossu, G.* AU - Boon, A.J.W.* AU - Kievit, A.J.A.* AU - Mandemakers, W.* AU - Bonifati, V.* AU - Jain, M.* AU - Jastroch, M.* AU - Schmitt-Kopplin, P. AU - Perocchi, F. AU - Dyar, K.A. C1 - 74394 C2 - 57484 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Pervasive glycative stress links metabolic imbalance and muscle atrophy in early-onset Parkinson's disease. JO - Mol. Metab. VL - 97 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - The Glucagon-like peptide-2 (GLP-2) analogue teduglutide is used clinically for the treatment of short bowel syndrome and intestinal failure occurring after extensive intestinal resection. A recently discovered effect of GLP-2 treatment is the inhibition of gallbladder motility and increased gallbladder refilling. However, the impact of these two GLP-2-characteristic effects on bile acid metabolism in health and after intestinal resection is not well characterized. To study effects of teduglutide treatment, we combined the selenium-75-homocholic acid taurine (SeHCAT) assay with novel spatial imaging in healthy mice and after ileocecal resection (ICR mice) and associated the results with clinical stage targeted bile acid metabolomics as well as gene expression analyses. ICR mice had virtual complete intestinal loss of secondary bile acids, and an increased ratio of 12α-hydroxylated vs. non-12α-hydroxylated bile acids, which was attenuated by teduglutide. Teduglutide promoted SeHCAT retention in healthy and in ICR mice. Acute concentration of the SeHCAT-signal into the hepatobiliary system was observed. Teduglutide induced significant repression of hepatic cyp8b1 expression, which was associated with induction of MAF BZIP Transcription Factor G. The data suggest that GLP-2-pharmacotherapy in mice significantly slows bile acid circulation primarily via hepatic Farnesoid X receptor-signaling. AU - Reiner, J.* AU - Mohebali, N.* AU - Kurth, J.* AU - Witte, M.* AU - Prehn, C. AU - Lindner, T.* AU - Berlin, P.* AU - Elleisy, N.* AU - Förster, R.H.* AU - Cecil, A. AU - Jaster, R.* AU - Adamski, J. AU - Schwarzenböck, S.M.* AU - Vollmar, B.* AU - Krause, B.J.* AU - Lamprecht, G.* C1 - 73711 C2 - 56894 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Glucagon-like peptide-2 pharmacotherapy activates hepatic Farnesoid X receptor-signaling to attenuate resection-associated bile acid loss in mice. JO - Mol. Metab. VL - 95 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - BACKGROUND: Extracellular vesicles (EVs), conveyors of microRNAs, have recently been linked to obesity. As taste is a potent driver of eating behaviour and food intake, it's connection to EVs is of increasing interest. This study aimed at deciphering the salivary EV-microRNA profile in relation to taste perception and metabolic pathways of obesity. METHODS: Small RNA sequencing was performed on isolated salivary EVs of 90 participants from the Obese-Taste-Bud study. Pathway enrichment and association analyses were conducted to link identified microRNAs to taste recognition, eating behaviour, food intake and various anthropometric-, metabolic- and oral health parameter. RESULTS: The 626 identified microRNAs clustered into pathways related to energy regulation, obesity and diabetes, cell signaling and taste perception. The top three enriched microRNAs are miR-1246, miR-1290 and miR-148a-3p which showed significant associations with fasting blood glucose and cholesterol level, anthropometrics and blood pressure (p<0.05). Additionally, these microRNAs associate with trait eating behaviour (p<0.05). Several other microRNAs were linked to differences in taste recognition scores and are further related to parameters of glucose metabolism and periodontal health, salivary insulin level or food intake (p<0.05). CONCLUSION: This study, one of the largest on salivary EVs, supports an interrelation of EV's microRNA load with metabolism, eating behaviour and taste recognition offering potential targets for obesity intervention. AU - Röhrborn, K. AU - Hoffmann, A. AU - Lorenz, A.* AU - Kovacs, P.* AU - Hagemann, T. AU - Czechowski, P. AU - Sehm, M.* AU - Horstmann, A.* AU - Stumvoll, M. AU - Blüher, M. AU - Schamarek, I. AU - Rohde-Zimmermann, K. C1 - 75728 C2 - 58211 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Salivary extracellular vesicle-derived microRNAs are related to variances in parameters of obesity, taste and eating behaviour. JO - Mol. Metab. VL - 102 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - Increasing evidence suggests that adipose tissue plays a key role in the development, progression, and treatment of the globally epidemic disease type 2 diabetes (T2D). For example, adipose tissue dysfunction, lipotoxicity, and insulin resistance (IR) are major contributors and targets for the treatment of T2D. We previously identified the Fibroblast growth factor 1 (FGF1) / Phosphodiesterase 4D (PDE4D) pathway, which lowers plasma glucose concentration by suppressing lipolysis in adipose tissue and ultimately regulating hepatic glucose production in obese insulin-resistant mice. While phosphorylation of PDE4D is critical for its activity, the upstream signaling mechanisms remain unclear. In this study, we identified p21-activated kinases (PAKs) as regulator of PDE4D phosphorylation and suppression of lipolysis by FGF1. Inhibition of PAK-induced cAMP accumulation prevented antilipolytic function of FGF1, and reversed suppression of lipolysis caused by PDE4D overexpression, linking PAKs to the regulation of cAMP by PDE4D in murine adipocytes in vitro. Chronic inhibition of PAKs decreased lipid accumulation in both mouse and human adipocyte cultures, lowered expression of adipogenic markers, and induced IR, suggesting a previously unidentified role of PAKs in adipocyte function and differentiation. We conclude that PAKs play a crucial role in regulating the FGF1/PDE4D antilipolytic pathway, adipogenesis and IR, thereby highlighting their potential as therapeutic targets for T2D. AU - Seigner, J. AU - Krier, J. AU - Spähn, D.* AU - Sandforth, L. AU - Nono, J.L. AU - Lukowski, R.* AU - Birkenfeld, A.L. AU - Sancar, G. C1 - 75146 C2 - 57838 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - p21-activated kinases (PAKs) regulate FGF1/PDE4D antilipolytic pathway and insulin resistance in adipocytes. JO - Mol. Metab. VL - 99 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Metabolic inflexibility has been shown to be associated with type 2 diabetes (T2D) and diabetic nephropathy (DN). However, data are lacking, proving that reconstitution of metabolic flexibility by using a 6-month periodic fasting (PF) regimen may improve albuminuria. RESEARCH DESIGN AND METHODS: In this post hoc analysis of a randomized-controlled trial, we investigated whether the PF regimen enhanced metabolic flexibility in individuals with T2D and DN showing improvement of albuminuria (responders) compared to non-responders. Participants followed every month either a 5-day fasting-mimicking diet or a Mediterranean diet for 6 months. LC-MS/MS-based comprehensive metabolic profiling was performed in plasma samples before, during, and after the intervention. Changes in metabolomic patterns and enriched signalling pathways were analysed between study groups. RESULTS: PF induced a sustained shift toward enhanced fatty acid oxidation, lipid utilization, and amino acids turnover, particularly in responders. Responders exhibited persistent elevations in short-chain acylcarnitines and cholesteryl esters, indicating more efficient lipid oxidation and tighter integration of lipid metabolism with the tricarboxylic acid cycle. Increased glycine and serine levels suggested enhanced cellular maintenance, a protein-sparing effect, and a metabolic shift favouring lipid over carbohydrate. In contrast, non-responders demonstrated only transient and limited metabolic shifts. Unsupervised clustering identified distinct metabolic response patterns, reinforcing the potential of personalized dietary interventions. CONCLUSIONS: These findings demonstrate that diet-induced restoration of metabolic flexibility is associated with improved albuminuria in T2D, suggesting broader implications for precise nutritional strategies in diabetes management. AU - Sulaj, A.* AU - Nguyen, B.H.P. AU - Poschet, G.* AU - Kliemank, E.* AU - Fleming, T.* AU - Henke, L.* AU - Neibig, W.* AU - Kopf, S.* AU - Hell, R.* AU - Longo, V.D.* AU - Herzig, S. AU - Nawroth, P.P. AU - Menden, M.P. AU - Szendroedi, J. C1 - 75642 C2 - 58220 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Periodic fasting induced reconstitution of metabolic flexibility improves albuminuria in patients with type 2 diabetes. JO - Mol. Metab. VL - 102 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - The cellular composition and functionality of adipose tissue are key determinants of metabolic diseases associated with adipose tissue dysregulation, such as obesity. We hypothesized that distinct subpopulations with unique gene expression profiles and functional characteristics exist within human adipocytes. Dedifferentiated adipocytes (DFAT), obtained by ceiling culture of human adipocytes, were analyzed using single-cell RNA sequencing (10x Genomics). Clustering analysis identified one subpopulation with a particular gene signature containing muscle cell genes. This subpopulation, named cluster 7 (C7), was isolated by FACS using two specific surface markers: cluster of differentiation 36 (CD36) and melanoma cell adhesion molecule (MCAM/CD146). Upon differentiation into adipocytes, the FACS-isolated CD36+/CD146+ cells (C7*) showed an increased oxygen consumption rate compared to CD36-/CD146- cells (control cells) and non-sorted cells. Bulk RNA-sequencing revealed important pathways regulated in the differentiated C7* subpopulation that may contribute to its increased metabolic activity. Furthermore, the relative abundance of this specific cluster varied across eleven different human donors, demonstrating an inverse correlation between the proportion of C7* cells and the body mass index (BMI) of the respective donor. Importantly, a subset of genes regulated within this subpopulation also correlates with clinically relevant metabolic parameters, including weight, BMI, glycated hemoglobin, and plasma insulin, when analyzed alongside the gene expression of a large cohort of human subcutaneous adipose tissue (1759 donors). Our results not only characterize DFAT cells derived from human adipose tissue, but also identify a specific subpopulation with increased energy expenditure that may play a role in body weight control. Future efforts to identify possible therapeutic targets or to promote the enrichment or activation of these energy-burning cells in adipose tissue might be useful in the field of cardiometabolic diseases. AU - Trujillo-Viera, J.* AU - Wittmann, M.C.* AU - Lam, D.D.* AU - Shen, Y.* AU - Ghosh, A.* AU - Noé, F.* AU - Hoffmann, A. AU - Viollet, C.* AU - Dick, A.* AU - Blüher, M. AU - Zhong, J.* AU - Massier, L. AU - Wolfrum, C.* AU - Klein, H.* AU - Neubauer, H.* AU - Hamilton, B.* C1 - 74492 C2 - 57490 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Abundance of a metabolically active subpopulation in dedifferentiated adipocytes inversely correlates with body mass index. JO - Mol. Metab. VL - 97 PB - Elsevier PY - 2025 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: The glucose-dependent insulinotropic polypeptide (GIP) decreases body weight via central GIP receptor (GIPR) signaling, but the underlying mechanisms remain largely unknown. Here, we assessed whether GIP regulates body weight and glucose control via GIPR signaling in cells that express the leptin receptor (Lepr). METHODS: Hypothalamic, hindbrain, and pancreatic co-expression of Gipr and Lepr was assessed using single cell RNAseq analysis. Mice with deletion of Gipr in Lepr cells were generated and metabolically characterized for alterations in diet-induced obesity (DIO), glucose control and leptin sensitivity. Long-acting single- and dual-agonists at GIPR and GLP-1R were further used to assess drug effects on energy and glucose metabolism in DIO wildtype (WT) and Lepr-Gipr knock-out (KO) mice. RESULTS: Gipr and Lepr show strong co-expression in the pancreas, but not in the hypothalamus and hindbrain. DIO Lepr-Gipr KO mice are indistinguishable from WT controls related to body weight, food intake and diet-induced leptin resistance, and acyl-GIP and the GIPR:GLP-1R co-agonist MAR709 remain fully efficacious to decrease body weight and food intake in DIO Lepr-Gipr KO mice. Consistent with the demonstration that Gipr and Lepr highly co-localize in the endocrine pancreas, including the β-cells, we find the superior glycemic effect of GIPR:GLP-1R co-agonism over single GLP-1R agonism to vanish in Lepr-Gipr KO mice. CONCLUSIONS: GIPR signaling in cells/neurons that express the leptin receptor is not implicated in the control of body weight or food intake, but is of crucial importance for the superior glycemic effects of GIPR:GLP-1R co-agonism relative to single GLP-1R agonism. AU - Akindehin, S.E. AU - Liskiewicz, A. AU - Liskiewicz, D. AU - Bernecker, M. AU - García-Cáceres, C. AU - Drucker, D.J.* AU - Finan, B.* AU - Grandl, G. AU - Gutgesell, R.M. AU - Hofmann, S.M. AU - Khalil, A. AU - Liu, X. AU - Cota, P. AU - Bakhti, M. AU - Czarnecki, O. AU - Bastidas-Ponce, A. AU - Lickert, H. AU - Kang, L. AU - Maity-Kumar, G. AU - Novikoff, A. AU - Parlee, S.* AU - Pathak, E. AU - Schriever, S.C. AU - Sterr, M. AU - Ussar, S. AU - Zhang, Q. AU - DiMarchi, R.* AU - Tschöp, M.H. AU - Pfluger, P.T. AU - Douros, J.D.* AU - Müller, T.D. C1 - 70237 C2 - 55453 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Loss of GIPR in LEPR cells impairs glucose control by GIP and GIP:GLP-1 co-agonism without affecting body weight and food intake in mice. JO - Mol. Metab. VL - 83 PB - Elsevier PY - 2024 SN - 2212-8778 ER - TY - JOUR AB - Retinitis pigmentosa (RP) is a hereditary retinal disease characterized by progressive photoreceptor degeneration, leading to vision loss. The best hope for a cure for RP lies in gene therapy. However, given that RP patients are most often diagnosed in the midst of ongoing photoreceptor degeneration, it is important to determine how the retinal proteome changes as RP disease progresses, and to identify which changes can be prevented, halted, or reversed by gene therapy. Here, we used our Pde6b-deficient RP gene therapy mouse model and demonstrated that Pde6b gene restoration led to a novel form of homeostatic plasticity in rod phototransduction which functionally compensates for the decreased number of rods. By profiling protein levels of metabolic genes and measuring metabolites, we observed an upregulation of proteins associated with oxidative phosphorylation in mutant and treated photoreceptors. Thus, the metabolic demands of the retina differ in our Pde6b-deficient RP mouse model and are not rescued by gene therapy treatment. These findings provide novel insights into features of both RP disease progression and long-term rescue with gene therapy. AU - Ayten, M.* AU - Díaz-Lezama, N.* AU - Ghanawi, H.* AU - Haffelder, F.C.* AU - Kajtna, J.* AU - Straub, T.* AU - Borsò, M.* AU - Imhof, A.* AU - Hauck, S.M. AU - Koch, S.F.* C1 - 71247 C2 - 55959 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Metabolic plasticity in a Pde6bSTOP/STOP retinitis pigmentosa mouse model following rescue. JO - Mol. Metab. VL - 88 PB - Elsevier PY - 2024 SN - 2212-8778 ER - TY - JOUR AB - With age, metabolic perturbations accumulate to elevate our obesity burden. While age-onset obesity is mostly driven by a sedentary lifestyle and high calorie intake, genetic and epigenetic factors also play a role. Among these, members of the large histone deacetylase (HDAC) family are of particular importance as key metabolic determinants for healthy ageing, or metabolic dysfunction. Here, we aimed to interrogate the role of class 2 family member HDAC5 in controlling systemic metabolism and age-related obesity under non-obesogenic conditions. Starting at 6 months of age, we observed adult-onset obesity in chow-fed male global HDAC5-KO mice, that was accompanied by marked reductions in adrenergic-stimulated ATP-consuming futile cycles, including BAT activity and UCP1 levels, WAT-lipolysis, skeletal muscle, WAT and liver futile creatine and calcium cycles, and ultimately energy expenditure. Female mice did not differ between genotypes. The lower peripheral sympathetic nervous system (SNS) activity in mature male KO mice was linked to higher dopaminergic neuronal activity within the dorsomedial arcuate nucleus (dmARC) and elevated hypothalamic dopamine levels. Mechanistically, we reveal that hypothalamic HDAC5 acts as co-repressor of STAT5b over the control of Tyrosine hydroxylase (TH) gene transactivation, which ultimately orchestrates the activity of dmARH dopaminergic neurons and energy metabolism in male mice under non-obesogenic conditions. AU - Contreras, R. AU - Gruber, T. AU - Gonzales García, I. AU - Schriever, S.C. AU - de Angelis, M. AU - Mallet, N. AU - Bernecker, M. AU - Legutko, B. AU - Kabra, D.G. AU - Schmidt, M.* AU - Tschöp, M.H. AU - Gutierrez-Aguilar, R.* AU - Mellor, J.* AU - García-Cáceres, C. AU - Pfluger, P.T. C1 - 71791 C2 - 56298 TI - HDAC5 controls a hypothalamic STAT5b-TH axis, the sympathetic activation of ATP-consuming futile cycles and adult-onset obesity in male mice. JO - Mol. Metab. VL - 90 PY - 2024 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: The consequences of mutations in genes associated with monogenic forms of diabetes on pancreas development cannot be studied in a time-resolved fashion in vivo. More specifically, if recessive mutations in the insulin gene influences human pancreatic endocrine lineage formation is still an unresolved question. METHODS: To model the extremely reduced insulin levels in patients with recessive insulin gene mutations, we generated a novel knock-in H2B-Cherry reporter human induced pluripotent stem cell (iPSCs) line expressing no insulin upon differentiation to stem cell-derived (SC-) β cells in vitro. Differentiation of iPSCs into the pancreatic and endocrine lineage, combined with immunostaining, Western blotting and proteomics analysis phenotypically characterized the insulin gene deficiency in SC-islets. Furthermore, we leveraged FACS analysis and imaging to explore the impact of insulin shortage on human endocrine cell induction, endocrine cell type composition, differentiation and proliferation. RESULTS: Interestingly, insulin-deficient SC-islets exhibited low insulin receptor (IR) signaling when stimulated with glucose but displayed increased IR sensitivity upon treatment with exogenous insulin. Furthermore, insulin shortage did not alter neurogenin-3 (NGN3)-mediated endocrine lineage induction. Nevertheless, lack of insulin skewed the SC-islet cell composition with an increased number in SC-β cell formation at the expense of SC-α cells. Finally, insulin deficiency reduced the rate of SC-β cell proliferation but had no impact on the expansion of SC-α cells. CONCLUSIONS: Using iPSC disease modelling, we provided first evidence of insulin function in human pancreatic endocrine lineage formation. These findings help to better understand the phenotypic impact of recessive insulin gene mutations during pancreas development and shed light on insulin gene function beside its physiological role in blood glucose regulation. AU - Cota, P. AU - Caliskan, Ö.S. AU - Bastidas-Ponce, A. AU - Jing, C. AU - Jaki, J. AU - Saber, L. AU - Czarnecki, O. AU - Taskin, D. AU - Blöchinger, A. AU - Kurth, T.* AU - Sterr, M. AU - Burtscher, I. AU - Krahmer, N. AU - Lickert, H. AU - Bakhti, M. C1 - 68969 C2 - 53789 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Insulin regulates human pancreatic endocrine cell differentiation in vitro. JO - Mol. Metab. VL - 79 PB - Elsevier PY - 2024 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Free fatty acid receptor-1 (FFAR1) is a medium- and long-chain fatty acid sensing G protein-coupled receptor that is highly expressed in the hypothalamus. Here, we investigated the central role of FFAR1 on energy balance. METHODS: Central FFAR1 agonism and virogenic knockdown were performed in mice. Energy balance studies, infrared thermographic analysis of brown adipose tissue (BAT) and molecular analysis of the hypothalamus, BAT, white adipose tissue (WAT) and liver were carried out. RESULTS: Pharmacological stimulation of FFAR1, using central administration of its agonist TUG-905 in diet-induced obese mice, decreases body weight and is associated with increased energy expenditure, BAT thermogenesis and browning of subcutaneous WAT (sWAT), as well as reduced AMP-activated protein kinase (AMPK) levels, reduced inflammation, and decreased endoplasmic reticulum (ER) stress in the hypothalamus. As FFAR1 is expressed in distinct hypothalamic neuronal subpopulations, we used an AAV vector expressing a shRNA to specifically knockdown Ffar1 in proopiomelanocortin (POMC) neurons of the arcuate nucleus of the hypothalamus (ARC) of obese mice. Our data showed that knockdown of Ffar1 in POMC neurons promoted hyperphagia and body weight gain. In parallel, these mice developed hepatic insulin resistance and steatosis. CONCLUSIONS: FFAR1 emerges as a new hypothalamic nutrient sensor regulating whole body energy balance. Moreover, pharmacological activation of FFAR1 could provide a therapeutic advance in the management of obesity and its associated metabolic disorders. AU - Dragano, N.R.V. AU - Milbank, E.* AU - Haddad-Tóvolli, R.* AU - Garrido-Gil, P.* AU - Novoa, E.* AU - Fondevilla, M.F.* AU - Capelli, V.* AU - Zanesco, A.M.* AU - Solon, C.* AU - Morari, J.* AU - Pires, L.* AU - Estevez-Salguero, A.* AU - Beiroa, D.* AU - González-García, I.* AU - Barca-Mayo, O.* AU - Diéguez, C.* AU - Nogueiras, R.* AU - Labandeira-García, J.L.* AU - Rexen Ulven, E.* AU - Ulven, T.* AU - Claret, M.* AU - Velloso, L.A.* AU - López, M.* C1 - 72983 C2 - 56765 TI - Hypothalamic free fatty acid receptor-1 regulates whole-body energy balance. JO - Mol. Metab. VL - 79 PY - 2024 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: AMP-activated protein kinase (AMPK) is a heterotrimer complex consisting of a catalytic α subunit (α1, α2) with a serine/threonine kinase domain, and two regulatory subunits, β (β1, β2) and γ (γ1, γ2, γ3), encoded by different genes. In the hypothalamus, AMPK plays a crucial role in regulating energy balance, including feeding, energy expenditure, peripheral glucose and lipid metabolism. However, most research on hypothalamic AMPK has concentrated on the catalytic subunits AMPKα1 and AMPKα2, with little focus on the regulatory subunits. METHODS: To fill this gap of knowledge, we investigated the effects of selectively deleting the regulatory isoform AMPKγ2, which is a primary "energy sensor", in steroidogenic factor 1 (SF1) neurons of the ventromedial hypothalamic nucleus (VMH). Complete metabolic phenotyping and molecular analyses in brown adipose tissue (BAT), white adipose tissue (WAT) and liver were carried out. RESULTS: Our findings reveal that, in contrast to the obesity-protective effect of the genetic deletion of AMPKα subunits, the loss of AMPKγ2 leads to a sex-independent and feeding-independent obesity-prone phenotype due to decreased thermogenesis in brown adipose tissue (BAT) and reduced browning of WAT, resulting in lower energy expenditure. Additionally, SF1-Cre AMPKγ2 mice exhibit hepatic lipid accumulation, but surprisingly maintain normal glucose homeostasis. CONCLUSIONS: Overall, these results highlight the distinct roles of AMPK subunits within the hypothalamus. AU - Freire-Agulleiro, Ó.* AU - Estévez-Salguero, Á.* AU - Ferreira, V.* AU - Holleman, C.L. AU - García-Currás, J.* AU - González-García, I.* AU - Nogueiras, R.* AU - Tena-Sempere, M.* AU - García-Cáceres, C. AU - Diéguez, C.* AU - López, M.* C1 - 72934 C2 - 56792 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - SF1-specific deletion of the energy sensor AMPKγ2 induces obesity. JO - Mol. Metab. VL - 92 PB - Elsevier PY - 2024 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Picalm (phosphatidylinositol-binding clathrin assembly protein), a ubiquitously expressed clathrin-adapter protein, is a well-known susceptibility gene for Alzheimer's disease, but its role in white adipose tissue (WAT) function has not yet been studied. Transcriptome analysis revealed differential expression of Picalm in WAT of diabetes-prone and diabetes-resistant mice, hence we aimed to investigate the potential link between Picalm expression and glucose homeostasis, obesity-related metabolic phenotypes, and its specific role in insulin-regulated GLUT4 trafficking in adipocytes. METHODS: Picalm expression and epigenetic regulation by microRNAs (miRNAs) and DNA methylation were analyzed in WAT of diabetes-resistant (DR) and diabetes-prone (DP) female New Zealand Obese (NZO) mice and in male NZO after time-restricted feeding (TRF) and alternate-day fasting (ADF). PICALM expression in human WAT was evaluated in a cross-sectional cohort and assessed before and after weight loss induced by bariatric surgery. siRNA-mediated knockdown of Picalm in 3T3-L1-adipocytes was performed to elucidate functional outcomes on GLUT4-translocation as well as insulin signaling and adipogenesis. RESULTS: Picalm expression in WAT was significantly lower in DR compared to DP NZO female mice, as well as in insulin-sensitive vs. resistant NZO males, and was also reduced in NZO males following TRF and ADF. Four miRNAs (let-7c, miR-30c, miR-335, miR-344) were identified as potential mediators of diabetes susceptibility-related differences in Picalm expression, while 11 miRNAs (including miR-23a, miR-29b, and miR-101a) were implicated in TRF and ADF effects. Human PICALM expression in adipose tissue was lower in individuals without obesity vs. with obesity and associated with weight-loss outcomes post-bariatric surgery. siRNA-mediated knockdown of Picalm in mature 3T3-L1-adipocytes resulted in amplified insulin-stimulated translocation of the endogenous glucose transporter GLUT4 to the plasma membrane and increased phosphorylation of Akt and Tbc1d4. Moreover, depleting Picalm before and during 3T3-L1 differentiation significantly suppressed adipogenesis, suggesting that Picalm may have distinct roles in the biology of pre- and mature adipocytes. CONCLUSIONS: Picalm is a novel regulator of GLUT4-translocation in WAT, with its expression modulated by both genetic predisposition to diabetes and dietary interventions. These findings suggest a potential role for Picalm in improving glucose homeostasis and highlight its relevance as a therapeutic target for metabolic disorders. AU - Gaugel, J.* AU - Haacke, N.* AU - Sehgal, R.* AU - Jähnert, M.* AU - Jonas, W.* AU - Hoffmann, A. AU - Blüher, M. AU - Ghosh, A.* AU - Noé, F.* AU - Wolfrum, C.* AU - Tan, J.* AU - Schürmann, A.* AU - Fazakerley, D.J.* AU - Vogel, H.* C1 - 71521 C2 - 56232 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Picalm, a novel regulator of GLUT4-trafficking in adipose tissue. JO - Mol. Metab. VL - 88 PB - Elsevier PY - 2024 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Sulfonylureas (SUs) are still among the mostly prescribed antidiabetic drugs with an established mode of action: release of insulin from pancreatic β-cells. In addition, effects of SUs on adipocytes by activation of the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) have been described, which might explain their insulin-sensitizing potential observed in patients. However, there is a discrepancy between the impact of SUs on antidiabetic action and their rather moderate in vitro effect on PPARγ transcriptional activity. Recent studies have shown that some PPARγ ligands can improve insulin sensitivity by blocking PPARγ Ser-273 phosphorylation without having full agonist activity. It is unknown if SUs elicit their antidiabetic effects on adipocytes by inhibition of PPARγ phosphorylation. Here, we investigated if binding of SUs to PPARγ can interfere with PPARγ Ser-273 phosphorylation and determined their antidiabetic actions in vitro in primary human white adipocytes and in vivo in high-fat diet (HFD) obese mice. METHODS: Primary human white preadipocytes were differentiated in the presence of glibenclamide, glimepiride and PPARγ ligands rosiglitazone and SR1664 to compare PPARγ Ser-273 phosphorylation, glucose uptake and adipokine expression. Transcriptional activity at PPARγ was determined by luciferase assays, quantification of PPARγ Ser-273 phosphorylation was determined by Western blotting and CDK5 kinase assays. In silico modelling was performed to gain insight into the binding characteristics of SUs to PPARγ. HFD mice were administered SUs and rosiglitazone for 6 days. PPARγ Ser-273 phosphorylation in white adipose tissue (WAT), body composition, glucose tolerance, adipocyte morphology and expression levels of genes involved in PPARγ activity in WAT and brown adipose tissue (BAT) were evaluated. RESULTS: SUs inhibit phosphorylation of PPARγ at Ser-273 in primary human white adipocytes and exhibit a positive antidiabetic expression profile, which is characterized by up regulation of insulin-sensitizing and down regulation of insulin resistance-inducing adipokines. We demonstrate that SUs directly bind to PPARγ by in silico modelling and inhibit phosphorylation in kinase assays to a similar extend as rosiglitazone and SR1664. In HFD mice SUs reduce PPARγ phosphorylation in WAT and have comparable effects on gene expression to rosiglitazone. In BAT SUs increase UCP1 expression and reduce lipid droplets sizes. CONCLUSIONS: Our findings indicate that a part of SUs extra-pancreatic effects on adipocytes in vitro and in vivo is probably mediated via their interference with PPARγ phosphorylation rather than via classical agonistic activity at clinical concentrations. AU - Haas, B.* AU - Sebastian Hass, M.D.* AU - Voltz, A.* AU - Vogel, M.* AU - Walther, J.* AU - Biswas, A.* AU - Haß, D. AU - Pfeifer, A.* C1 - 70645 C2 - 55794 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Sulfonylureas exert antidiabetic action on adipocytes by inhibition of PPARγ serine 273 phosphorylation. JO - Mol. Metab. VL - 85 PB - Elsevier PY - 2024 SN - 2212-8778 ER - TY - JOUR AB - The authors regret that the abstract of the originally published paper contains an error in the use of “increased” instead of “decreased”. The last sentence of the abstract should read: “Conclusion: We conclude that adipocyte Gαi2 is a major regulator of adipocyte lipid content in diet-induced obesity by inhibiting adipocyte lipolysis in a cAMP-dependent manner resulting in decreased energy expenditure.” The authors would like to apologise for any inconvenience caused. AU - Leiss, V.* AU - Schönsiegel, A.* AU - Gnad, T.* AU - Kerner, J.* AU - Kaur, J.* AU - Sartorius, T. AU - Machann, J. AU - Schick, F.* AU - Birnbaumer, L.* AU - Häring, H.-U. AU - Pfeifer, A.* AU - Nürnberg, B.* C1 - 70186 C2 - 55447 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Corrigendum to "Lack of Gαi2 proteins in adipocytes attenuates diet-induced obesity" [Mol Metab 40 (2020 Oct) 101029]. JO - Mol. Metab. VL - 82 PB - Elsevier PY - 2024 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Kallistatin (KST), also known as SERPIN A4, is a circulating, broadly acting human plasma protein with pleiotropic properties. Clinical studies in humans revealed reduced KST levels in obesity. The exact role of KST in glucose and energy homeostasis in the setting of insulin resistance and type 2 diabetes is currently unknown. METHODS: Kallistatin mRNA expression in human subcutaneous white adipose tissue (sWAT) of 47 people with obesity of the clinical trial "Comparison of Low Fat and Low Carbohydrate Diets With Respect to Weight Loss and Metabolic Effects (B-SMART)" was measured. Moreover, we studied transgenic mice systemically overexpressing human KST (hKST-TG) and wild type littermate control mice (WT) under normal chow (NCD) and high-fat diet (HFD) conditions. RESULTS: In sWAT of people with obesity, KST mRNA increased after diet-induced weight loss. On NCD, we did not observe differences between hKST-TG and WT mice. Under HFD conditions, body weight, body fat and liver fat content did not differ between genotypes. Yet, during intraperitoneal glucose tolerance tests (ipGTT) insulin excursions and HOMA-IR were lower in hKST-TG (4.42 ± 0.87 AU, WT vs. 2.20 ± 0.27 AU, hKST-TG, p < 0.05). Hyperinsulinemic euglycemic clamp studies with tracer-labeled glucose infusion confirmed improved insulin sensitivity by higher glucose infusion rates in hKST-TG mice (31.5 ± 1.78 mg/kg/min, hKST-TG vs. 18.1 ± 1.67 mg/kg/min, WT, p < 0.05). Improved insulin sensitivity was driven by reduced hepatic insulin resistance (clamp hepatic glucose output: 7.7 ± 1.9 mg/kg/min, hKST-TG vs 12.2 ± 0.8 mg/kg/min, WT, p < 0.05), providing evidence for direct insulin sensitizing effects of KST for the first time. Insulin sensitivity was differentially affected in skeletal muscle and adipose tissue. Mechanistically, we observed reduced WNT signaling in the liver but not skeletal muscle, which may explain the effect. CONCLUSIONS: KST expression increases after weight loss in sWAT from people with obesity. Furthermore, human KST ameliorates diet-induced hepatic insulin resistance in mice, while differentially affecting skeletal muscle and adipose tissue insulin sensitivity. Thus, KST may be an interesting, yet challenging, therapeutic target for patients with obesity and insulin resistance. AU - Sandforth, L. AU - Brachs, S.* AU - Reinke, J.* AU - Willmes, D.* AU - Sancar, G. AU - Seigner, J. AU - Juarez Lopez, D.A. AU - Sandforth, A. AU - McBride, J.D.* AU - Ma, J.X.* AU - Haufe, S.* AU - Jordan, J.* AU - Birkenfeld, A.L. C1 - 70091 C2 - 55415 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Role of human Kallistatin in glucose and energy homeostasis in mice. JO - Mol. Metab. VL - 82 PB - Elsevier PY - 2024 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: We here assessed whether typical pathogens of laboratory mice affect the development of diet-induced obesity and glucose intolerance, and whether colonization affects the efficacy of the GLP-1R agonist liraglutide and of the GLP-1/GIP co-agonist MAR709 to treat obesity and diabetes. METHODS: Male C57BL/6J mice were experimentally infected with Helicobacter hepaticus, Rodentibacter pneumotropicus and Staphylococcus aureus and compared to a group of uninfected specific and opportunistic pathogen free (SOPF) mice. The development of diet-induced obesity and glucose intolerance was monitored over a period of 26 weeks. To study the influence of pathogens on drug treatment, mice were then subjected for 6 days daily treatment with either the GLP-1 receptor agonist liraglutide or the GLP-1/GIP co-agonist MAR709. RESULTS: Colonized mice did not differ from SOPF controls regarding HFD-induced body weight gain, food intake, body composition, glycemic control, or responsiveness to treatment with liraglutide or the GLP-1/GIP co-agonist MAR709. CONCLUSIONS: We conclude that the occurrence of Helicobacter hepaticus, Rodentibacter pneumotropicus and Staphylococcus aureus does neither affect the development of diet-induced obesity or type 2 diabetes, nor the efficacy of GLP-1-based drugs to decrease body weight and to improve glucose control in mice. AU - Wunderlich, M. AU - Miller, M. AU - Ritter, B. AU - Le Gleut, R. AU - Marchi, H. AU - Majzoub-Altweck, M.* AU - Knerr, P.J.* AU - Douros, J.D.* AU - Müller, T.D. AU - Brielmeier, M. C1 - 71211 C2 - 56009 TI - Experimental colonization with H. hepaticus, S. aureus and R. pneumotropicus does not influence the metabolic response to high-fat diet or incretin-analogues in wildtype SOPF mice. JO - Mol. Metab. VL - 87 PY - 2024 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Snacking, i.e., the intake of small amounts of palatable food items, is a common behavior in modern societies, promoting overeating and obesity. Shifting food intake into the daily rest phase disrupts circadian rhythms and is also known to stimulate weight gain. We therefore hypothesized that chronic snacking in the inactive phase may promote body weight gain and that this effect is based on disruption of circadian clocks. METHODS: Male mice were fed a daily chocolate snack either during their rest or their active phase and body weight development and metabolic parameters were investigated. Snacking experiments were repeated in constant darkness and in clock-deficient mutant mice to examine the role of external and internal time cues in mediating the metabolic effects of snacking. RESULTS: Chronic snacking in the rest phase increased body weight gain and disrupted metabolic circadian rhythms in energy expenditure, body temperature, and locomotor activity. Additionally, these rest phase snacking mice assimilated more energy during the inactive phase. Body weight remained increased in rest phase snacking wildtype mice in constant darkness as well as in clock-deficient mutant mice under a regular light-dark cycle compared to mice snacking in the active phase. Weight gain effects were abolished in clock-deficient mice in constant darkness. CONCLUSIONS: Our data suggest that mistimed snacking increases energy resorption and promotes body weight gain. This effect requires a functional circadian clock at least under constant darkness conditions. AU - Begemann, K.* AU - Heyde, I.* AU - Witt, P.* AU - Inderhees, J.* AU - Leinweber, B.* AU - Koch, C.E.* AU - Jöhren, O.* AU - Oelkrug, R.* AU - Liskiewicz, A. AU - Müller, T.D. AU - Oster, H.* C1 - 67486 C2 - 54154 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Rest phase snacking increases energy resorption and weight gain in male mice. JO - Mol. Metab. VL - 69 PB - Elsevier PY - 2023 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVES: Cancer is considered an emerging diabetes complication, with higher incidence and worse prognosis in patients with diabetes. Cancer is frequently associated with cachexia, a systemic metabolic disease causing wasting. It is currently unclear how diabetes affects the development and progression of cachexia. METHODS: We investigated the interplay between diabetes and cancer cachexia retrospectively in a cohort of 345 patients with colorectal and pancreatic cancer. We recorded body weight, fat mass, muscle mass, clinical serum values, and survival of these patients. Patients were grouped either into diabetic/non-diabetic groups based on previous diagnosis, or into obese/non-obese groups based on body mass index (BMI ≥30 kg/m2 was considered obese). RESULTS: The pre-existence of type 2 diabetes, but not obesity, in patients with cancer led to increased cachexia incidence (80%, compared to 61% without diabetes, p ≤ 0.05), higher weight loss (8.9% vs. 6.0%, p ≤ 0.001), and reduced survival probability (median survival days: 689 vs. 538, Chi square = 4.96, p ≤ 0.05) irrespective of the initial body weight or tumor progression. Patients with diabetes and cancer showed higher serum levels of C-reactive protein (0.919 μg/mL vs. 0.551 μg/mL, p ≤ 0.01) and interleukin 6 (5.98 pg/mL vs. 3.75 pg/mL, p ≤ 0.05) as well as lower serum albumin levels (3.98 g/dL vs. 4.18 g/dL, p ≤ 0.05) than patients with cancer without diabetes. In a sub-analysis of patients with pancreatic cancer, pre-existing diabetes worsened weight loss (9.95% vs. 6.93%, p ≤ 0.01), and increased the duration of hospitalization (24.41 days vs. 15.85 days, p ≤ 0.001). Further, diabetes aggravated clinical manifestations of cachexia, as changes in the aforementioned biomarkers were more pronounced in patients with diabetes and cachexia co-existence, compared to cachectic patients without diabetes (C-reactive protein: 2.300 μg/mL vs. 0.571 μg/mL, p ≤ 0.0001; hemoglobin: 11.24 g/dL vs. 12.52 g/dL, p ≤ 0.05). CONCLUSIONS: We show for the first time that pre-existing diabetes aggravates cachexia development in patients with colorectal and pancreatic cancer. This is important when considering cachexia biomarkers and weight management in patients with co-existing diabetes and cancer. AU - Chovsepian, A. AU - Prokopchuk, O.* AU - Petrova, G.* AU - Gjini, T.* AU - Kuzi, H.* AU - Heisz, S.* AU - Janssen, K.P.* AU - Martignoni, M.E.* AU - Friess, H.* AU - Hauner, H* AU - Rohm, M. C1 - 67670 C2 - 53977 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Diabetes increases mortality in patients with pancreatic and colorectal cancer by promoting cachexia and its associated inflammatory status. JO - Mol. Metab. VL - 73 PB - Elsevier PY - 2023 SN - 2212-8778 ER - TY - JOUR AB - Endothelin receptor B (ETB) together with ETA mediates cellular effects of endothelin 1 (ET-1), an autocrine and endocrine peptide produced by the endothelium and other cells. It regulates vascular tone and controls kidney function. Metabolic syndrome is due to high caloric intake and is characterized by insulin resistance, dyslipidemia, and white adipose tissue (WAT) accumulation. ETA/ETB antagonism has been demonstrated to favorably influence insulin resistance. Our study explored the role of ETB in metabolic syndrome. Wild type (etb+/+) and rescued ETB-deficient (etb-/-) mice were fed a high-fat diet, and energy, glucose, and insulin metabolism were analyzed, and hormones and lipids measured in serum and tissues. Cell culture experiments were performed in HepG2 cells. Compared to etb+/+ mice, etb-/- mice exhibited better glucose tolerance and insulin sensitivity, less WAT accumulation, lower serum triglycerides, and higher energy expenditure. Protection from metabolic syndrome was paralleled by higher hepatic production of fibroblast growth factor 21 (FGF21) and higher serum levels of free thyroxine (fT4), stimulators of energy expenditure. In conclusion, ETB deficiency confers protection from metabolic syndrome by counteracting glucose intolerance, dyslipidemia, and WAT accumulation due to enhanced energy expenditure, effects at least in part dependent on enhanced production of thyroid hormone/FGF21. ETB antagonism may therefore be a novel therapeutic approach in metabolic syndrome. AU - Feger, M.* AU - Meier, L.* AU - Strotmann, J.* AU - Hoene, M.* AU - Vogt, J.* AU - Wisser, A.* AU - Hirschle, S.* AU - Kheim, M.J.* AU - Hocher, B.* AU - Weigert, C. AU - Föller, M.* C1 - 69023 C2 - 53808 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Endothelin receptor B-deficient mice are protected from high-fat diet-induced metabolic syndrome. JO - Mol. Metab. VL - 80 PB - Elsevier PY - 2023 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVES: Global cardiometabolic disease prevalence has grown rapidly over the years, making it the leading cause of death worldwide. Proteins are crucial components in biological pathways dysregulated in disease states. Identifying genetic components that influence circulating protein levels may lead to the discovery of biomarkers for early stages of disease or offer opportunities as therapeutic targets. METHODS: Here, we carry out a genome-wide association study (GWAS) utilising whole genome sequencing data in 3,005 individuals from the HELIC founder populations cohort, across 92 proteins of cardiometabolic relevance. RESULTS: We report 322 protein quantitative trait loci (pQTL) signals across 92 proteins, of which 76 are located in or near the coding gene (cis-pQTL). We link those association signals with changes in protein expression and cardiometabolic disease risk using colocalisation and Mendelian randomisation (MR) analyses. CONCLUSIONS: The majority of previously unknown signals we describe point to proteins or protein interactions involved in inflammation and immune response, providing genetic evidence for the contributing role of inflammation in cardiometabolic disease processes. AU - Gilly, A. AU - Park, Y.-C. AU - Tsafantakis, E.* AU - Karaleftheri, M.* AU - Dedoussis, G.* AU - Zeggini, E. C1 - 68635 C2 - 54819 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Genome-wide meta-analysis of 92 cardiometabolic protein serum levels. JO - Mol. Metab. VL - 78 PB - Elsevier PY - 2023 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Mice with global deletion of the transient receptor potential channel melastatin family member 8 (TRPM8) are obese, and treatment of diet-induced obese (DIO) mice with TRPM8 agonists decrease body weight. Whether TRPM8 signaling regulates energy metabolism via central or peripheral effects is unknow. Here we assessed the metabolic phenotype of mice with either Nestin Cre-mediated neuronal loss of TRPM8, or with deletion of TRPM8 in Advillin Cre positive sensory neurons of the peripheral nervous system (PNS). METHODS: Nestin Cre- and Advillin Cre-Trpm8 knock-out (KO) mice were metabolically phenotyped under chronic exposure to either chow or high-fat diet (HFD), followed by assessment of energy and glucose metabolism. RESULTS: At room temperature, chow-fed neuronal Trpm8 KO are obese and show decreased energy expenditure when acutely treated with the TRPM8 selective agonist icilin. But body weight of neuronal Trpm8 KO mice is indistinguishable from wildtype controls at thermoneutrality, or when mice are chronically exposed to HFD-feeding. In contrast to previous studies, we show that the TRPM8 agonist icilin has no direct effect on brown adipocytes, but that icilin stimulates energy expenditure, at least in part, via neuronal TRPM8 signaling. We further show that lack of TRPM8 in sensory neurons of the PNS does not lead to a metabolically relevant phenotype. CONCLUSIONS: Our data indicate that obesity in TRPM8-deficient mice is centrally mediated and likely originates from alterations in energy expenditure and/or thermal conductance, but does not depend on TRPM8 signaling in brown adipocytes or sensory neurons of the PVN. AU - Liskiewicz, D. AU - Zhang, Q. AU - Barthem, C.S.* AU - Jastroch, M.* AU - Liskiewicz, A. AU - Khajavi, N.* AU - Grandl, G. AU - Coupland, C. AU - Kleinert, M. AU - García-Cáceres, C. AU - Novikoff, A. AU - Maity-Kumar, G. AU - Boehm, U.* AU - Tschöp, M.H. AU - Müller, T.D. C1 - 67663 C2 - 53970 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Neuronal loss of TRPM8 leads to obesity and glucose intolerance in male mice. JO - Mol. Metab. VL - 72 PB - Elsevier PY - 2023 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Cancer cells convert more glucose into lactate than healthy cells, what contributes to their growth advantage. Pyruvate kinase (PK) is a key rate limiting enzyme in this process, what makes it a promising potential therapeutic target. However, currently it is still unclear what consequences the inhibition of PK has on cellular processes. Here, we systematically investigate the consequences of PK depletion for gene expression, histone modifications and metabolism. METHODS: Epigenetic, transcriptional and metabolic targets were analysed in different cellular and animal models with stable knockdown or knockout of PK. RESULTS: Depleting PK activity reduces the glycolytic flux and causes accumulation of glucose-6-phosphate (G6P). Such metabolic perturbation results in stimulation of the activity of a heterodimeric pair of transcription factors MondoA and MLX but not in a major reprogramming of the global H3K9ac and H3K4me3 histone modification landscape. The MondoA:MLX heterodimer upregulates expression of thioredoxin-interacting protein (TXNIP) - a tumour suppressor with multifaceted anticancer activity. This effect of TXNIP upregulation extends beyond immortalised cancer cell lines and is applicable to multiple cellular and animal models. CONCLUSIONS: Our work shows that actions of often pro-tumorigenic PK and anti-tumorigenic TXNIP are tightly linked via a glycolytic intermediate. We suggest that PK depletion stimulates the activity of MondoA:MLX transcription factor heterodimers and subsequently, increases cellular TXNIP levels. TXNIP-mediated inhibition of thioredoxin (TXN) can reduce the ability of cells to scavenge reactive oxygen species (ROS) leading to the oxidative damage of cellular structures including DNA. These findings highlight an important regulatory axis affecting tumour suppression mechanisms and provide an attractive opportunity for combination cancer therapies targeting glycolytic activity and ROS-generating pathways. AU - Nieborak, A. AU - Lukauskas, S. AU - Capellades, J.* AU - Heyn, P. AU - Santos, G.S. AU - Motzler, K. AU - Zeigerer, A. AU - Bester, R. AU - Protzer, U. AU - Schelter, F.* AU - Wagner, M.* AU - Carell, T.* AU - Hruscha, A.* AU - Schmid, B.* AU - Yanes, O.* AU - Schneider, R. C1 - 67839 C2 - 54317 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Depletion of pyruvate kinase (PK) activity causes glycolytic intermediate imbalances and reveals a PK-TXNIP regulatory axis. JO - Mol. Metab. VL - 74 PB - Elsevier PY - 2023 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVES: Better disease management can be achieved with earlier detection through robust, sensitive, and easily accessible biomarkers. The aim of the current study was to identify novel epigenetic biomarkers determining the risk of type 2 diabetes (T2D). METHODS: Livers of 10-week-old female New Zealand Obese (NZO) mice, slightly differing in their degree of hyperglycemia and liver fat content and thereby in their diabetes susceptibility were used for expression and methylation profiling. We screened for differences in hepatic expression and DNA methylation in diabetes-prone and -resistant mice, and verified a candidate (HAMP) in human livers and blood cells. Hamp expression was manipulated in primary hepatocytes and insulin-stimulated pAKT was detected. Luciferase reporter assays were conducted in a murine liver cell line to test the impact of DNA methylation on promoter activity. RESULTS: In livers of NZO mice, the overlap of methylome and transcriptome analyses revealed a potential transcriptional dysregulation of 12 hepatokines. The strongest effect with a 52% decreased expression in livers of diabetes-prone mice was detected for the Hamp gene, mediated by elevated DNA methylation of two CpG sites located in the promoter. Hamp encodes the iron-regulatory hormone hepcidin, which had a lower abundance in the livers of mice prone to developing diabetes. Suppression of Hamp reduces the levels of pAKT in insulin-treated hepatocytes. In liver biopsies of obese insulin-resistant women, HAMP expression was significantly downregulated along with increased DNA methylation of a homologous CpG site. In blood cells of incident T2D cases from the prospective EPIC-Potsdam cohort, higher DNA methylation of two CpG sites was related to increased risk of incident diabetes. CONCLUSIONS: We identified epigenetic changes in the HAMP gene which may be used as an early marker preceding T2D. AU - Ouni, M.* AU - Eichelmann, F.* AU - Jähnert, M.* AU - Krause, C.* AU - Saussenthaler, S.* AU - Ott, C.* AU - Gottmann, P.* AU - Speckmann, T.* AU - Huypens, P. AU - Wolter, S.* AU - Mann, O.* AU - Hrabě de Angelis, M. AU - Beckers, J. AU - Kirchner, H.* AU - Schulze, M.B.* AU - Schürmann, A.* C1 - 68127 C2 - 54605 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Differences in DNA methylation of HAMP in blood cells predicts the development of type 2 diabetes. JO - Mol. Metab. VL - 75 PB - Elsevier PY - 2023 SN - 2212-8778 ER - TY - JOUR AB - Objective: To gain mechanistic insights into adverse effects of maternal hyperglycemia on the liver of neonates, we performed a multi-omics analysis of liver tissue from piglets developed in genetically diabetic (mutant INS gene induced diabetes of youth; MIDY) or wild-type (WT) pigs. Methods: Proteome, metabolome and lipidome profiles of liver and clinical parameters of serum samples from 3-day-old WT piglets (n = 9) born to MIDY mothers (PHG) were compared with those of WT piglets (n = 10) born to normoglycemic mothers (PNG). Furthermore, protein–protein interaction network analysis was used to reveal highly interacting proteins that participate in the same molecular mechanisms and to relate these mechanisms with human pathology. Results: Hepatocytes of PHG displayed pronounced lipid droplet accumulation, although the abundances of central lipogenic enzymes such as fatty acid-synthase (FASN) were decreased. Additionally, circulating triglyceride (TG) levels were reduced as a trend. Serum levels of non-esterified free fatty acids (NEFA) were elevated in PHG, potentially stimulating hepatic gluconeogenesis. This is supported by elevated hepatic phosphoenolpyruvate carboxykinase (PCK1) and circulating alanine transaminase (ALT) levels. Even though targeted metabolomics showed strongly elevated phosphatidylcholine (PC) levels, the abundances of multiple key enzymes involved in major PC synthesis pathways – most prominently those from the Kennedy pathway – were paradoxically reduced in PHG liver. Conversely, enzymes involved in PC excretion and breakdown such as PC-specific translocase ATP-binding cassette 4 (ABCB4) and phospholipase A2 were increased in abundance. Conclusions: Our study indicates that maternal hyperglycemia without confounding obesity induces profound molecular changes in the liver of neonatal offspring. In particular, we found evidence for stimulated gluconeogenesis and hepatic lipid accumulation independent of de novo lipogenesis. Reduced levels of PC biosynthesis enzymes and increased levels of proteins involved in PC translocation or breakdown may represent counter-regulatory mechanisms to maternally elevated PC levels. Our comprehensive multi-omics dataset provides a valuable resource for future meta-analysis studies focusing on liver metabolism in newborns from diabetic mothers. AU - Shashikadze, B.* AU - Valla, L.* AU - Lombardo, S.D.* AU - Prehn, C. AU - Haid, M. AU - Riols, F. AU - Stöckl, J.B.* AU - Elkhateib, R.* AU - Renner, S.* AU - Rathkolb, B. AU - Menche, J.* AU - Hrabě de Angelis, M. AU - Wolf, E.* AU - Kemter, E.* AU - Fröhlich, T.* C1 - 68395 C2 - 54623 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Maternal hyperglycemia induces alterations in hepatic amino acid, glucose and lipid metabolism of neonatal offspring: Multi-omics insights from a diabetic pig model. JO - Mol. Metab. VL - 75 PB - Elsevier PY - 2023 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: The insulin/insulin-like growth factor 1 (IGF1) pathway is emerging as a crucial component of prostate cancer progression. Therefore, we investigated the role of the novel insulin/IGF1 signaling modulator inceptor in prostate cancer. METHODS: We analyzed the expression of inceptor in human samples of benign prostate epithelium and prostate cancer. Further, we performed signaling and functional assays using prostate cancer cell lines. RESULTS: We found that inceptor was expressed in human benign and malignant prostate tissue and its expression positively correlated with various genes of interest, including genes involved in androgen signaling. In vitro, total levels of inceptor were increased upon androgen deprivation and correlated with high levels of androgen receptor in the nucleus. Inceptor overexpression was associated with increased cell migration, altered IGF1R trafficking and higher IGF1R activation. CONCLUSIONS: Our in vitro results showed that inceptor expression was associated with androgen status, increased migration, and IGF1R signaling. In human samples, inceptor expression was significantly correlated with markers of prostate cancer progression. Taken together, these data provide a basis for investigation of inceptor in the context of prostate cancer. AU - Wissmiller, K. AU - Bilekova, S. AU - Frankó, A. AU - Lutz, S.Z.* AU - Katsburg, M. AU - Gulde, S. AU - Pellegata, N.S. AU - Stenzl, A.* AU - Heni, M. AU - Berti, L. AU - Häring, H.-U. AU - Lickert, H. C1 - 67715 C2 - 54023 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Inceptor correlates with markers of prostate cancer progression and modulates insulin/IGF1 signaling and cancer cell migration. JO - Mol. Metab. VL - 71 PB - Elsevier PY - 2023 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Deep sequencing offers unparalleled access to rare variants in human populations. Understanding their role in disease is a priority, yet prohibitive sequencing costs mean that many cohorts lack the sample size to discover these effects on their own. Meta-analysis of individual variant scores allows the combination of rare variants across cohorts and study of their aggregated effect at the gene level, boosting discovery power. However, the methods involved have largely not been field-tested. In this study, we aim to perform the first meta-analysis of gene-based rare variant aggregation optimal tests, applied to the human cardiometabolic proteome. METHODS: Here, we carry out this analysis across MANOLIS, Pomak and ORCADES, three isolated European cohorts with whole-genome sequencing (total N = 4,422). We examine the genetic architecture of 250 proteomic traits of cardiometabolic relevance. We use a containerised pipeline to harmonise variant lists across cohorts and define four sets of qualifying variants. For every gene, we interrogate protein-damaging variants, exonic variants, exonic and regulatory variants, and regulatory only variants, using the CADD and Eigen scores to weigh variants according to their predicted functional consequence. We perform single-cohort rare variant analysis and meta-analyse variant scores using the SMMAT package. RESULTS: We describe 5 rare variant pQTLs (RV-pQTL) which pass our stringent significance threshold (7.45 × 10-11) and quality control procedure. These were split between four cis signals for MARCO, TEK, MMP2 and MPO, and one trans association for GDF2 in the SERPINA11 gene. We show that the cis-MPO association, which was not detectable using the single-point data alone, is driven by 5 missense and frameshift variants. These include rs140636390 and rs119468010, which are specific to MANOLIS and ORCADES, respectively. We show how this kind of signal could improve the predictive accuracy of genetic factors in common complex disease such as stroke and cardiovascular disease. CONCLUSIONS: Our proof-of-concept study demonstrates the power of gene-based meta-analyses for discovering disease-relevant associations complementing common-variant signals by incorporating population-specific rare variation. AU - Gilly, A. AU - Klaric, L.* AU - Park, Y.-C. AU - Png, G. AU - Barysenska, A. AU - Marsh, J.A.* AU - Tsafantakis, E.* AU - Karaleftheri, M.* AU - Dedoussis, G.* AU - Wilson, J.F.* AU - Zeggini, E. C1 - 65028 C2 - 52621 TI - Gene-based whole genome sequencing meta-analysis of 250 circulating proteins in three isolated European populations. JO - Mol. Metab. VL - 61 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Multiple GWAS have identified SNPs in the 8q24 locus near TRIB1 that significantly associate with plasma lipids and other markers of cardiometabolic health, and prior studies have uncovered roles for hepatic and myeloid Trib1 in plasma lipid regulation and atherosclerosis. The same 8q24 SNPs additionally associate with plasma adiponectin levels in humans, implicating TRIB1 in adipocyte biology. Here, we hypothesize that TRIB1 in adipose tissue regulates plasma adiponectin, lipids, and metabolic health. METHODS: We investigate the metabolic phenotype of adipocyte-specific Trib1 knockout mice (Trib1_ASKO) on chow and high fat diet. Through secretomics of adipose tissue explants and RNA-seq of adipocytes and livers from these mice, we further investigate the mechanism of TRIB1 in adipose tissue. RESULTS: Trib1_ASKO mice have an improved metabolic phenotype with increased plasma adiponectin levels, improved glucose tolerance, and decreased plasma lipids. Trib1_ASKO adipocytes have increased adiponectin production and secretion independent of the known TRIB1 function of regulating proteasomal degradation. RNA-seq analysis of adipocytes and livers from Trib1_ASKO mice suggests that alterations in adipocyte function underlie the observed plasma lipid changes. Adipose tissue explant secretomics further reveals that Trib1_ASKO adipose tissue has decreased ANGPTL4 production, and we demonstrate an accompanying increase in LPL activity that likely underlies the triglyceride phenotype. CONCLUSION: Adipocyte Trib1 regulates multiple aspects of metabolic health, confirming previously observed genetic associations in humans and shedding light on further mechanisms by which TRIB1 regulates plasma lipids and metabolic health. AU - Ha, E.E.* AU - Quartuccia, G.I.* AU - Ling, R.* AU - Xue, C.* AU - Karikari, R.A. AU - Hernandez-Ono, A.* AU - Hu, K.Y.* AU - Matias, C.V.* AU - Imam, R.* AU - Cui, J.* AU - Pellegata, N.S. AU - Herzig, S. AU - Georgiadi, A. AU - Soni, R.K.* AU - Bauer, R.C.* C1 - 63781 C2 - 51756 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Adipocyte-specific tribbles pseudokinase 1 regulates plasma adiponectin and plasma lipids in mice. JO - Mol. Metab. VL - 56 PB - Elsevier PY - 2022 SN - 2212-8778 ER - TY - JOUR AU - Herzig, S. C1 - 65763 C2 - 52897 TI - 10 years of molecular metabolism. JO - Mol. Metab. VL - 63 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - Background: Single-cell metabolic studies bring new insights into cellular function, which can often not be captured on other omics layers. Metabolic information has wide applicability, such as for the study of cellular heterogeneity or for the understanding of drug mechanisms and biomarker development. However, metabolic measurements on single-cell level are limited by insufficient scalability and sensitivity, as well as resource intensiveness, and are currently not possible in parallel with measuring transcript state, commonly used to identify cell types. Nevertheless, because omics layers are strongly intertwined, it is possible to make metabolic predictions based on measured data of more easily measurable omics layers together with prior metabolic network knowledge. Scope of review: We summarize the current state of single-cell metabolic measurement and modeling approaches, motivating the use of computational techniques. We review three main classes of computational methods used for prediction of single-cell metabolism: pathway-level analysis, constraint-based modeling, and kinetic modeling. We describe the unique challenges arising when transitioning from bulk to single-cell modeling. Finally, we propose potential model extensions and computational methods that could be leveraged to achieve these goals. Major conclusions: Single-cell metabolic modeling is a rising field that provides a new perspective for understanding cellular functions. The presented modeling approaches vary in terms of input requirements and assumptions, scalability, modeled metabolic layers, and newly gained insights. We believe that the use of prior metabolic knowledge will lead to more robust predictions and will pave the way for mechanistic and interpretable machine-learning models. AU - Hrovatin, K. AU - Fischer, D.S. AU - Theis, F.J. C1 - 64092 C2 - 51691 TI - Toward modeling metabolic state from single-cell transcriptomics JO - Mol. Metab. VL - 57 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Ferroptosis continues to emerge as a novel modality of cell death with important therapeutic implications for a variety of diseases, most notably cancer and degenerative diseases. While susceptibility, initiation, and execution of ferroptosis have been linked to reprogramming of cellular lipid metabolism, imbalances in iron-redox homeostasis, and aberrant mitochondrial respiration, the detailed mechanisms of ferroptosis are still insufficiently well understood. METHODS AND RESULTS: Here we show that diminished proteasome function is a new mechanistic feature of ferroptosis. The transcription factor nuclear factor erythroid-2, like-1 (NFE2L1) protects from ferroptosis by sustaining proteasomal activity. In cellular systems, loss of NFE2L1 reduced cellular viability after the induction of both chemically and genetically induced ferroptosis, which was linked to the regulation of proteasomal activity under these conditions. Importantly, this was reproduced in a Sedaghatian-type Spondylometaphyseal Dysplasia (SSMD) patient-derived cell line carrying mutated glutathione peroxidase-4 (GPX4), a critical regulator of ferroptosis. Also, reduced proteasomal activity was associated with ferroptosis in Gpx4-deficient mice. In a mouse model for genetic Nfe2l1 deficiency, we observed brown adipose tissue (BAT) involution, hyperubiquitination of ferroptosis regulators, including the GPX4 pathway, and other hallmarks of ferroptosis. CONCLUSION: Our data highlight the relevance of the NFE2L1-proteasome pathway in ferroptosis. Manipulation of NFE2L1 activity might enhance ferroptosis-inducing cancer therapies as well as protect from aberrant ferroptosis in neurodegeneration, general metabolism, and beyond. AU - Kotschi, S.* AU - Jung, A.* AU - Willemsen, N.* AU - Ofoghi, A.* AU - Proneth, B. AU - Conrad, M. AU - Bartelt, A. C1 - 63996 C2 - 52039 TI - NFE2L1-mediated proteasome function protects from ferroptosis. JO - Mol. Metab. VL - 57 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: The Allan-Herndon-Dudley syndrome (AHDS) is a severe disease caused by dysfunctional central thyroid hormone transport due to functional loss of the monocarboxylate transporter 8 (MCT8). In this study, we assessed whether mice with concomitant deletion of the thyroid hormone transporters Mct8 and the organic anion transporting polypeptide (Oatp1c1) represent a valid preclinical model organism for the AHDS. METHODS: We generated and metabolically characterized a new CRISPR/Cas9 generated Mct8/Oatp1c1 double-knockout (dKO) mouse line for the clinical features observed in patients with AHDS. RESULTS: We show that Mct8/Oatp1c1 dKO mice mimic key hallmarks of the AHDS, including decreased life expectancy, central hypothyroidism, peripheral hyperthyroidism, impaired neuronal myelination, impaired motor abilities and enhanced peripheral thyroid hormone action in the liver, adipose tissue, skeletal muscle and bone. CONCLUSIONS: We conclude that Mct8/Oatp1c1 dKO mice are a valuable model organism for the preclinical evaluation of drugs designed to treat the AHDS. AU - Maity-Kumar, G. AU - Ständer, L. AU - de Angelis, M. AU - Lee, S.* AU - Molenaar, A. AU - Becker, L. AU - Garrett, L. AU - Amarie, O.V. AU - Hölter, S.M. AU - Wurst, W.* AU - Fuchs, H. AU - Feuchtinger, A. AU - Gailus-Durner, V. AU - García-Cáceres, C. AU - Othman, A.E.* AU - Brockmann, C.* AU - Schöffling, V.I.* AU - Beiser, K.* AU - Krude, H.* AU - Mroz, P.A.* AU - Hofmann, S.M. AU - Tuckermann, J.* AU - DiMarchi, R.D.* AU - Hrabě de Angelis, M. AU - Tschöp, M.H. AU - Pfluger, P.T. AU - Müller, T.D. C1 - 66469 C2 - 52844 TI - Validation of Mct8/Oatp1c1 dKO mice as a model organism for the Allan-Herndon-Dudley Syndrome. JO - Mol. Metab. VL - 66 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Classical ATP-independent non-shivering thermogenesis enabled by uncoupling protein 1 (UCP1) in brown adipose tissue (BAT) is activated, but not essential for survival, in the cold. It has long been suspected that futile ATP-consuming substrate cycles also contribute to thermogenesis and can partially compensate for the genetic ablation of UCP1 in mouse models. Futile ATP-dependent thermogenesis could thereby enable survival in the cold even when brown fat is less abundant or missing. METHODS: In this study, we explore different potential sources of UCP1-independent thermogenesis and identify a futile ATP-consuming triglyceride/fatty acid cycle as the main contributor to cellular heat production in brown adipocytes lacking UCP1. We uncover the mechanism on a molecular level and pinpoint the key enzymes involved using pharmacological and genetic interference. RESULTS: ATGL is the most important lipase in terms of releasing fatty acids from lipid droplets, while DGAT1 accounts for the majority of fatty acid re-esterification in UCP1-ablated brown adipocytes. Furthermore, we demonstrate that chronic cold exposure causes a pronounced remodeling of adipose tissues and leads to the recruitment of lipid cycling capacity specifically in BAT of UCP1-knockout mice, possibly fueled by fatty acids from white fat. Quantification of triglyceride/fatty acid cycling clearly shows that UCP1-ablated animals significantly increase turnover rates at room temperature and below. CONCLUSION: Our results suggest an important role for futile lipid cycling in adaptive thermogenesis and total energy expenditure. AU - Oeckl, J.* AU - Janovska, P.* AU - Adamcova, K.* AU - Bardova, K.* AU - Brunner, S.* AU - Dieckmann, S.* AU - Ecker, J.* AU - Fromme, T.* AU - Funda, J.* AU - Gantert, T.* AU - Giansanti, P.* AU - Hidrobo, M.S.* AU - Kuda, O.* AU - Kuster, B.* AU - Li, Y.* AU - Pohl, R.* AU - Schmitt, S.* AU - Schweizer, S.* AU - Zischka, H. AU - Zouhar, P.* AU - Kopecky, J.* AU - Klingenspor, M.* C1 - 64863 C2 - 52524 TI - Loss of UCP1 function augments recruitment of futile lipid cycling for thermogenesis in murine brown fat. JO - Mol. Metab. VL - 61 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVES: Obesity in humans and mice is associated with elevated levels of two hormones responsive to cellular stress, namely GDF15 and FGF21. Over-expression of each of these is associated with weight loss and beneficial metabolic changes but where they are secreted from and what they are required for physiologically in the context of overfeeding remains unclear. METHODS: Here we used tissue selective knockout mouse models and human transcriptomics to determine the source of circulating GDF15 in obesity. We then generated and characterized the metabolic phenotypes of GDF15/FGF21 double knockout mice. RESULTS: Circulating GDF15 and FGF21 are both largely derived from the liver, rather than adipose tissue or skeletal muscle, in obese states. Combined whole body deletion of FGF21 and GDF15 does not result in any additional weight gain in response to high fat feeding but it does result in significantly greater hepatic steatosis and insulin resistance than that seen in GDF15 single knockout mice. CONCLUSIONS: Collectively the data suggest that overfeeding activates a stress response in the liver which is the major source of systemic rises in GDF15 and FGF21. These hormones then activate pathways which reduce this metabolic stress. AU - Patel, S.* AU - Haider, A.* AU - Alvarez-Guaita, A.* AU - Bidault, G.* AU - El-Sayed Moustafa, J.S.* AU - Guiu-Jurado, E.* AU - Tadross, J.A.* AU - Warner, J.* AU - Harrison, J.* AU - Virtue, S.* AU - Scurria, F.* AU - Zvetkova, I.* AU - Blüher, M. AU - Small, K.S.* AU - O'Rahilly, S.* AU - Savage, D.B.* C1 - 66176 C2 - 53113 TI - Combined genetic deletion of GDF15 and FGF21 has modest effects on body weight, hepatic steatosis and insulin resistance in high fat fed mice. JO - Mol. Metab. VL - 65 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - Objective: The circadian clock aligns physiology with the 24-hour rotation of Earth. Light and food are the main environmental cues (zeitgebers) regulating circadian rhythms in mammals. Yet, little is known about the interaction between specific dietary components and light in coordinating circadian homeostasis. Herein, we focused on the role of essential amino acids. Methods: Mice were fed diets depleted of specific essential amino acids and their behavioral rhythms were monitored and tryptophan was selected for downstream analyses. The role of tryptophan metabolism in modulating circadian homeostasis was studied using isotope tracing as well as transcriptomic- and metabolomic- analyses. Results: Dietary tryptophan depletion alters behavioral rhythms in mice. Furthermore, tryptophan metabolism was shown to be regulated in a time- and light- dependent manner. A multi-omics approach and combinatory diet/light interventions demonstrated that tryptophan metabolism modulates temporal regulation of metabolism and transcription programs by buffering photic cues. Specifically, tryptophan metabolites regulate central circadian functions of the suprachiasmatic nucleus and the core clock machinery in the liver. Conclusions: Tryptophan metabolism is a modulator of circadian homeostasis by integrating environmental cues. Our findings propose tryptophan metabolism as a potential point for pharmacologic intervention to modulate phenotypes associated with disrupted circadian rhythms. AU - Petrus, P.* AU - Cervantes, M.* AU - Samad, M.* AU - Sato, T.* AU - Chao, A.* AU - Sato, S.* AU - Koronowski, K.B.* AU - Park, G.* AU - Alam, Y.* AU - Mejhert, N.* AU - Seldin, M.M.* AU - Monroy Kuhn, J.M. AU - Dyar, K.A. AU - Lutter, D. AU - Baldi, P.* AU - Kaiser, P.* AU - Jang, C.* AU - Sassone-Corsi, P.* C1 - 65904 C2 - 52971 TI - Tryptophan metabolism is a physiological integrator regulating circadian rhythms. JO - Mol. Metab. VL - 64 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - Background: The highly complex pathogenesis of Type 1 Diabetes is driven by several immune cell types with both effector and regulatory characteristics, which ultimately ends in the destruction of the insulin-producing beta cells. There are multiple layers of interaction between these immune cell populations and the pancreatic islets. Scope of review: In this review article, we aim to discuss important recent insights into the multiple layers of interaction between immune cell populations and the pancreatic islets. Specifically, we discuss the environment where immune and beta cell interactions occur, the key cell types and molecules involved, and the outcomes of these interactions. Major conclusions: Most of the molecular mechanisms underlying aberrant immune cell activation and impaired immune tolerance remain insufficiently understood, which hinders the development of efficient prevention and treatment strategies. In order to overcome this knowledge gap, a better understanding of the complex interactions of immune cells and beta cells, including both the underlying protective and pathogenic mechanisms is urgently required. AU - Scherm, M.G. AU - Wyatt, R.C.* AU - Serr, I. AU - Anz, D.* AU - Richardson, S.J.* AU - Daniel, C. C1 - 65941 C2 - 52991 TI - Beta cell and immune cell interactions in autoimmune type 1 diabetes: How they meet and talk to each other. JO - Mol. Metab. VL - 64 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - Objective: Pancreatic islets of Langerhans secrete hormones to regulate systemic glucose levels. Emerging evidence suggests that islet cells are functionally heterogeneous to allow a fine-tuned and efficient endocrine response to physiological changes. A precise description of the molecular basis of this heterogeneity, in particular linking animal models to human islets, is an important step towards identifying the factors critical for endocrine cell function in physiological and pathophysiological conditions. Methods: In this study, we used single-cell RNA sequencing to profile more than 50′000 endocrine cells isolated from healthy human, pig and mouse pancreatic islets and characterize transcriptional heterogeneity and evolutionary conservation of those cells across the three species. We systematically delineated endocrine cell types and α- and β-cell heterogeneity through prior knowledge- and data-driven gene sets shared across species, which altogether capture common and differential cellular properties, transcriptional dynamics and putative driving factors of state transitions. Results: We showed that global endocrine expression profiles correlate, and that critical identity and functional markers are shared between species, while only approximately 20% of cell type enriched expression is conserved. We resolved distinct human α- and β-cell states that form continuous transcriptional landscapes. These states differentially activate maturation and hormone secretion programs, which are related to regulatory hormone receptor expression, signaling pathways and different types of cellular stress responses. Finally, we mapped mouse and pig cells to the human reference and observed that the spectrum of human α- and β-cell heterogeneity and aspects of such functional gene expression are better recapitulated in the pig than mouse data. Conclusions: Here, we provide a high-resolution transcriptional map of healthy human islet cells and their murine and porcine counterparts, which is easily queryable via an online interface. This comprehensive resource informs future efforts that focus on pancreatic endocrine function, failure and regeneration, and enables to assess molecular conservation in islet biology across species for translational purposes. AU - Tritschler, S. AU - Thomas, M. AU - Böttcher, A. AU - Ludwig, B. AU - Schmid, J.* AU - Schubert, U.* AU - Kemter, E.* AU - Wolf, E.* AU - Lickert, H. AU - Theis, F.J. C1 - 66302 C2 - 53131 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - A transcriptional cross species map of pancreatic islet cells. JO - Mol. Metab. VL - 66 PB - Elsevier PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - Brown adipose tissue (BAT) burns fatty acids (FAs) to produce heat, and shows diurnal oscillation in glucose and triglyceride (TG)-derived FA-uptake, peaking around wakening. To gain insight in the diurnal regulation of metabolic BAT activity, we employed RNA-sequencing and lipidomics in murine BAT and identified pronounced enrichment of oscillating genes involved in extracellular lipolysis accompanied by oscillations of FA and monoacylglycerol content. This coincided with peak lipoprotein lipase (Lpl) expression, and was predicted to be driven by peroxisome proliferator-activated receptor gamma (PPARγ) activity. Chromatin immunoprecipitation (ChIP)-sequencing for PPARγ confirmed oscillation in binding of PPARγ to Lpl. Of the known LPL-modulators, angiopoietin-like 4 (Angptl4) showed the largest diurnal amplitude opposite to Lpl, and both Angptl4 knockout and overexpression attenuated oscillations of LPL and TG-derived FA-uptake by BAT. Our findings highlight involvement of PPARγ and a crucial role of ANGPTL4 in mediating the diurnal oscillation of TG-derived FA-uptake by BAT, and imply that time of day is essential when targeting LPL activity in BAT to improve metabolic health. AU - van Eenige, R.* AU - In Het Panhuis, W.* AU - Schönke, M.* AU - Jouffe, C. AU - Devilee, T.H.* AU - Siebeler, R.* AU - Streefland, T.C.M.* AU - Sips, H.C.M.* AU - Pronk, A.C.M.* AU - Vorderman, R.H.P.* AU - Mei, H.* AU - van Klinken, J.B.* AU - van Weeghel, M.* AU - Uhlenhaut, N.H.* AU - Kersten, S.* AU - Rensen, P.C.N.* AU - Kooijman, S.* C1 - 64796 C2 - 52495 TI - Angiopoietin-like 4 governs diurnal lipoprotein lipase activity in brown adipose tissue. JO - Mol. Metab. VL - 60 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Nonalcoholic fatty liver disease (NAFLD) ranges from steatosis to nonalcoholic steatohepatitis (NASH), which often progresses to hepatocellular carcinoma (HCC) through a largely undefined mechanism. NASH and HCC depend on inflammatory signaling, whose master regulator is the NFκB transcription factor family, activated by canonical and non-canonical pathways. METHODS: Here, we investigated non-canonical NFκB-inducing kinase (NIK/MAP3K14) in metabolic NASH, NASH to HCC transition, and DEN-induced HCC. To this end, we performed dietary and chemical interventions in mice that were analyzed via single nucleus sequencing, gene expression and histochemical methods. Ultimately, we verified our mouse results in human patient samples. RESULTS: We revealed that hepatocyte-specific NIK deficiency (NIKLKO) ameliorated metabolic NASH complications and reduced hepatocarcinogenesis, independent of its role in the NFκB pathway. Instead, hepatic NIK attenuated hepatoprotective JAK2/STAT5 signaling that is a prerequisite for NASH and NASH to HCC progression in mice and humans. CONCLUSIONS: Our data suggest NIK-mediated inhibitory JAK2 phosphorylation at serine 633 that might be amenable for future therapeutic interventions in patients. AU - Vesting, A.J.* AU - Jais, A. AU - Klemm, P.* AU - Steuernagel, L.* AU - Wienand, P.* AU - Fog-Tonnesen, M.* AU - Hvid, H.* AU - Schumacher, A.L.* AU - Kukat, C.* AU - Nolte, H.* AU - Georgomanolis, T.* AU - Altmüller, J.* AU - Pasparakis, M.* AU - Schmidt, A.* AU - Krüger, M.* AU - Supprian, M.S.* AU - Waisman, A.* AU - Straub, B.K.* AU - Raschzok, N.* AU - Bernier, M.* AU - Birkenfeld, A.L. AU - Hövelmeyer, N.* AU - Brüning, J.C.* AU - Wunderlich, F.T.* C1 - 66681 C2 - 53274 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - NIK/MAP3K14 in hepatocytes orchestrates NASH to hepatocellular carcinoma progression via JAK2/STAT5 inhibition. JO - Mol. Metab. VL - 66 PB - Elsevier PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Brown adipocytes play a key role in maintaining body temperature as well as glucose and lipid homeostasis. However, brown adipocytes need to adapt their thermogenic activity and substrate utilization to changes in nutrient availability. Amongst the multiple factors influencing brown adipocyte activity, autophagy is an important regulatory element of thermogenic capacity and activity. Nevertheless, a specific sensing mechanism of extracellular amino acid availability linking autophagy to nutrient availability in brown adipocytes is unknown. METHODS: To characterize the role of the amino acid transporter PAT2/SLC36A2 in brown adipocytes, loss or gain of function of PAT2 were studied with respect to differentiation, subcellular localization, lysosomal activity and autophagy. Activity of vATPase was evaluated by quenching of EGFP fused to LC3 or FITC-dextran loaded lysosomes in brown adipocytes upon amino acid starvation, whereas the effect of PAT2 on assembly of the vATPase was investigated by Native-PAGE. RESULTS: We show that PAT2 translocates from the plasma membrane to the lysosome in response to amino acid withdrawal. Loss or overexpression of PAT2 impair lysosomal acidification and starvation-induced S6K re-phosphorylation, as PAT2 facilitates the assembly of the lysosomal vATPase, by recruitment of the cytoplasmic V1 subunit to the lysosome. CONCLUSIONS: PAT2 is an important sensor of extracellular amino acids and regulator of lysosomal acidification in brown adipocytes. AU - Wang, J. AU - Onogi, Y. AU - Krueger, M.* AU - Oeckl, J.* AU - Karlina, R. AU - Singh, I. AU - Hauck, S.M. AU - Feederle, R. AU - Li, Y.* AU - Ussar, S. C1 - 65021 C2 - 52617 TI - PAT2 regulates vATPase assembly and lysosomal acidification in brown adipocytes. JO - Mol. Metab. VL - 61 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Regulation of proteasomal activity is an essential component of cellular proteostasis and function. This is evident in patients with mutations in proteasome subunits and associated regulators, who suffer from proteasome-associated autoinflammatory syndromes (PRAAS). These patients display lipodystrophy and fevers, which may be partly related to adipocyte malfunction and abnormal thermogenesis in adipose tissue. However, the cell-intrinsic pathways that could underlie these symptoms are unclear. Here, we investigate the impact of two proteasome subunits implicated in PRAAS, Psmb4 and Psmb8, on differentiation, function and proteostasis of brown adipocytes. METHODS: In immortalized mouse brown pre-adipocytes, levels of Psmb4, Psmb8, and downstream effectors genes were downregulated through reverse transfection with siRNA. Adipocytes were differentiated and analyzed with various assays of adipogenesis, lipogenesis, lipolysis, inflammation, and respiration. RESULTS: Loss of Psmb4, but not Psmb8, disrupted proteostasis and adipogenesis. Proteasome function was reduced upon Psmb4 loss, but partly recovered by the activation of Nuclear factor, erythroid-2, like-1 (Nfe2l1). In addition, cells displayed higher levels of surrogate inflammation and stress markers, including Activating transcription factor-3 (Atf3). Simultaneous silencing of Psmb4 and Atf3 lowered inflammation and restored adipogenesis. CONCLUSIONS: Our study shows that Psmb4 is required for adipocyte development and function in cultured adipocytes. These results imply that in humans with PSMB4 mutations, PRAAS-associated lipodystrophy is partly caused by disturbed adipogenesis. While we uncover a role for Nfe2l1 in the maintenance of proteostasis under these conditions, Atf3 is a key effector of inflammation and blocking adipogenesis. In conclusion, our work highlights how proteasome dysfunction is sensed and mitigated by the integrated stress response in adipocytes with potential relevance for PRAAS patients and beyond. AU - Willemsen, N.* AU - Arigoni, I.* AU - Studencka-Turski, M.* AU - Kruger, E.* AU - Bartelt, A. C1 - 65478 C2 - 52700 TI - Proteasome dysfunction disrupts adipogenesis and induces inflammation via ATF3. JO - Mol. Metab. VL - 62 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - Objective: Fibrotic organ responses have recently been identified as long-term complications in diabetes. Indeed, insulin resistance and aberrant hepatic lipid accumulation represent driving features of progressive non-alcoholic fatty liver disease (NAFLD), ranging from simple steatosis and non-alcoholic steatohepatitis (NASH) to fibrosis. Effective pharmacological regimens to stop progressive liver disease are still lacking to-date. Methods: Based on our previous discovery of transforming growth factor beta-like stimulated clone (TSC)22D4 as a key driver of insulin resistance and glucose intolerance in obesity and type 2 diabetes, we generated a TSC22D4-hepatocyte specific knockout line (TSC22D4-HepaKO) and exposed mice to control or NASH diet models. Mechanistic insights were generated by metabolic phenotyping and single-nuclei RNA sequencing. Results: Hepatic TSC22D4 expression was significantly correlated with markers of liver disease progression and fibrosis in both murine and human livers. Indeed, hepatic TSC22D4 levels were elevated in human NASH patients as well as in several murine NASH models. Specific genetic deletion of TSC22D4 in hepatocytes led to reduced liver lipid accumulation, improvements in steatosis and inflammation scores and decreased apoptosis in mice fed a lipogenic MCD diet. Single-nuclei RNA sequencing revealed a distinct TSC22D4-dependent gene signature identifying an upregulation of mitochondrial-related processes in hepatocytes upon loss of TSC22D4. An enrichment of genes involved in the TCA cycle, mitochondrial organization, and triglyceride metabolism underscored the hepatocyte-protective phenotype and overall decreased liver damage as seen in mouse models of hepatocyte-selective TSC22D4 loss-of-function. Conclusions: Together, our data uncover a new connection between targeted depletion of TSC22D4 and intrinsic metabolic processes in progressive liver disease. Hepatocyte-specific reduction of TSC22D4 improves hepatic steatosis and promotes hepatocyte survival via mitochondrial-related mechanisms thus paving the way for targeted therapies. AU - Wolff, G. AU - Sakurai, M. AU - Mhamane, A. AU - Troullinaki, M. AU - Maida, A. AU - Deligiannis, I.K. AU - Yin, K. AU - Weber, P. AU - Morgenstern, J. AU - Wieder, A. AU - Kwon, Y. AU - Sekar, R. AU - Zeigerer, A. AU - Roden, M.* AU - Blüher, M. AU - Volk, N.* AU - Poth, T.* AU - Hackert, T.* AU - Wiedmann, L.* AU - De Angelis Rigotti, F.* AU - Rodriguez-Vita, J.* AU - Fischer, A.* AU - Mukthavaram, R.* AU - Limphong, P.* AU - Tachikawa, K.* AU - Karmali, P.* AU - Payne, J.* AU - Chivukula, P.* AU - Ekim Üstünel, B. AU - Martinez Jimenez, C.P. AU - Szendrödi, J. AU - Nawroth, P.P. AU - Herzig, S. C1 - 64780 C2 - 52454 TI - Hepatocyte-specific activity of TSC22D4 triggers progressive NAFLD by impairing mitochondrial function. JO - Mol. Metab. VL - 60 PY - 2022 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: The molecular pathogenesis of late complications associated with type 2 diabetes mellitus (T2DM) is not yet fully understood. While high glucose levels indicated by increased HbA1c only poorly explain disease progression and late complications, a pro-inflammatory status, oxidative stress and reactive metabolites generated by metabolic processes were postulated to be involved. Individuals with metabolic syndrome (MetS) frequently progress to T2DM, whereby 70% of T2DM patients show non-alcoholic fatty liver disease (NAFLD), the hepatic manifestation of MetS, and insulin resistance (IR). Epidemiological studies have shown that T2DM and steatosis are associated with alterations in iron metabolism and hepatic iron accumulation. Excess free iron triggers oxidative stress and a switch towards a macrophage pro-inflammatory status. However, so far it remains unclear if hepatic iron accumulation plays a causative role in the generation of IR and T2DM or whether it is merely a manifestation of altered hepatic metabolism. To address this open question, we have generated and characterized a mouse model of T2DM with IR, steatosis and iron overload. METHODS: Leprdb/db mice hallmarked by T2DM, IR and steatosis were crossed with Fpnwt/C326S mice with systemic iron overload to generate Leprdb/db/Fpnwt/C326S mice. The resulting progeny was characterized for major diabetic and iron-related parameters. RESULTS: We show that features associated with T2DM in Leprdb/db mice, such as obesity, steatosis or insulin resistance reduce the degree of tissue iron overload in Fpnwt/C326S mice, suggesting an 'iron resistance' phenotype. By contrast, we observe increased serum iron levels that strongly exceed those in the iron-overloaded Fpnwt/C326S mice. Increased hepatic iron levels induce oxidative stress and lipid peroxidation and aggravate insulin resistance, as indicated by diminished IRS1 phosphorylation and AKT activation. Additionally, in the liver we observe gene response patterns indicative of de novo lipogenesis and increased gluconeogenesis as well as elevated free glucose levels. Finally, we show that iron overload in Leprdb/db/Fpnwt/C326S mice enhances microvascular complications observed in retinopathy, suggesting that iron accumulation can enhance diabetic late complications associated with the liver and the eye. CONCLUSION: Taken together, our data show that iron causes the worsening of symptoms associated with the metabolic syndrome and T2DM. These findings imply that iron depletion strategies together with anti-diabetic drugs may ameliorate insulin resistance and diabetic late complications. AU - Altamura, S.* AU - Müdder, K.* AU - Schlotterer, A.* AU - Fleming, T. AU - Poschet, G.* AU - Qiu, R.* AU - Hammes, H.P.* AU - Nawroth, P.P. AU - Muckenthaler, M.U.* C1 - 61834 C2 - 50480 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Iron aggravates hepatic insulin resistance in the absence of inflammation in a novel db/db mouse model with iron overload. JO - Mol. Metab. VL - 51 PB - Elsevier PY - 2021 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Protein disulfide isomerases (PDIs) are oxidoreductases that are involved in catalyzing the formation and rearrangement of disulfide bonds during protein folding. One of the PDI members is the PDI-associated 6 (PDIA6) protein, which has been shown to carry a vital role in β-cell dysfunction and diabetes. However, very little is known about the function of this protein in β-cells in vivo. This study aimed to describe the consequences of a point mutation in Pdia6 on β-cell development and function. METHODS: We generated an ENU mouse model carrying a missense mutation (Phe175Ser) in the second thioredoxin domain of the Pdia6 gene. Using biochemical and molecular tools, we determined the effects of the mutation on the β-cell development at embryonic day (E)18.5 and β-cell identity as well as function at postnatal stages. RESULTS: Mice homozygous for the Phe175Ser (F175S) mutation were mildly hyperglycemic at weaning and subsequently became hypoinsulinemic and overtly diabetic at the adult stage. Although, no developmental phenotype was detected during embryogenesis, mutant mice displayed reduced insulin-expressing β-cells at P14 and P21 without any changes in the rate of cell death and proliferation. Further analysis revealed an increase in BiP as well as PDI family member PDIA4, however without any concomitant apoptosis and cell death. Instead, the expression of prominent markers of β-cell maturation and function, such as Ins2, Mafa and Slc2a2 along with increased expression of α-cell markers, Mafb and glucagon was observed in adult mice, suggesting loss of β-cell identity. CONCLUSIONS: The data demonstrates that a global Pdia6 mutation renders mice hypoinsulinemic and hyperglycemic. This occurs due to the loss of pancreatic β-cell function and identity, suggesting a critical role of PDIA6 specifically for β-cells. AU - Chhabra, N.F. AU - Amend, A.-L. AU - Bastidas-Ponce, A. AU - Sabrautzki, S. AU - Tarquis Medina, M. AU - Sachs, S. AU - Rubey, M. AU - Lorenz-Depiereux, B. AU - Feuchtinger, A. AU - Bakhti, M. AU - Lickert, H. AU - Przemeck, G.K.H. AU - Hrabě de Angelis, M. C1 - 62954 C2 - 51024 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - A point mutation in the Pdia6 gene results in loss of pancreatic β-cell identity causing overt diabetes. JO - Mol. Metab. VL - 54 PB - Elsevier PY - 2021 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Postprandial lipid profiling (PLP), a risk indicator ofcardiometabolic disease, is based on frequent blood sampling over several hours after a meal, an approach that is invasive and inconvenient. Non-invasive PLP may offer an alternative for disseminated human monitoring. Herein, we investigate the use of clinical Multispectral Optoacoustic Tomography (MSOT) for the non-invasive, label-free PLP via direct lipid-sensing in human vasculature and soft tissues. METHODS: Four (n = 4) subjects (3 females and 1 male, age: 28 ± 7 years) were enrolled in the current pilot study. We longitudinally measured the lipid signals in arteries, veins, skeletal muscles and adipose tissues of all participants at 30 min-intervalsfor 6 hours after the oral consumption of a high-fat meal. RESULTS: Optoacoustic lipid-signal analysis showed on average a 63.4% intra-arterial increase at ∼4 hours postprandially, a 83.9% intra-venous increase at ∼3 hours, a 120.8% intra-muscular increase at ∼3 hours and a 32.8% subcutaneous fat increase at ∼4 hours. CONCLUSION: MSOT provides the potential to study lipid metabolism that could lead to novel diagnostics and prevention strategies by label-free, non-invasive detection of tissue biomarkers implicated in cardiometabolic diseases. AU - Fasoula, N.-A. AU - Karlas, A. AU - Kallmayer, M.* AU - Milik, A.B. AU - Pelisek, J.* AU - Eckstein, H.H.* AU - Klingenspor, M.* AU - Ntziachristos, V. C1 - 61337 C2 - 50131 TI - Multicompartmental non-invasive sensing of postprandial lipemia in humans with multispectral optoacoustic tomography. JO - Mol. Metab. VL - 47 PY - 2021 SN - 2212-8778 ER - TY - JOUR AU - Gonzales García, I. AU - Le Thuc, O. AU - Jastroch, M. AU - García-Cáceres, C. C1 - 61226 C2 - 50103 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Divide et impera: How mitochondrial fission in astrocytes rules obesity. JO - Mol. Metab. VL - 45 PB - Elsevier PY - 2021 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Liver mitochondria adapt to high calorie intake. We investigated how exercise alters the early compensatory response of mitochondria and thus prevents fatty liver disease as a long-term consequence of overnutrition. METHODS: We compared the effects of a steatogenic high-energy diet (HED, for 6 weeks) on mitochondrial metabolism of sedentary and treadmill-trained C57BL/6N mice. We applied multi-OMICs analyses to study the alterations in the proteome, transcriptome and lipids in isolated mitochondria of liver and skeletal muscle as well as in whole tissue and examined the functional consequences by high resolution respirometry. RESULTS: HED increased the respiratory capacity of isolated liver mitochondria, both in sedentary and in trained mice. However, proteomics analysis of the mitochondria and transcriptomics indicated that training modified the adaptation of the hepatic metabolism to HED on the level of respiratory complex I, glucose oxidation, pyruvate and acetyl-CoA metabolism and lipogenesis. Training also counteracted the HED-induced increase in fasting insulin, glucose tolerance, and liver fat. This was accompanied by lower diacylglycerol species and JNK phosphorylation in the livers of trained HED-fed mice, two mechanisms that can reverse hepatic insulin resistance. In skeletal muscle, the combination of HED and training improved the oxidative capacity to a greater extent than training alone by increasing respiration of isolated mitochondria and total mitochondrial protein content. CONCLUSION: We provide a comprehensive insight into the early adaptations of mitochondria in liver and skeletal muscle to HED and endurance training. Our results suggest that exercise disconnects the HED-induced increase in mitochondrial substrate oxidation from pyruvate and acetyl-CoA-driven lipid synthesis. This could contribute to the prevention of deleterious long-term effects of high fat and sugar intake on hepatic mitochondrial function and insulin sensitivity. AU - Hoene, M.* AU - Kappler, L.* AU - Kollipara, L.* AU - Hu, C.* AU - Irmler, M. AU - Bleher, D.* AU - Hoffmann, C.* AU - Beckers, J. AU - Hrabě de Angelis, M. AU - Häring, H.-U. AU - Birkenfeld, A.L. AU - Peter, A. AU - Sickmann, A.* AU - Xu, G.* AU - Lehmann, R. AU - Weigert, C. C1 - 63445 C2 - 51455 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Exercise prevents fatty liver by modifying the compensatory response of mitochondrial metabolism to excess substrate availability. JO - Mol. Metab. VL - 54 PB - Elsevier PY - 2021 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Obesity, in particular visceral obesity, and insulin resistance emerged as major risk factors for severe Coronavirus Disease 2019 (COVID-19), which is strongly associated with hemostatic alterations. Since obesity and insulin resistance predispose to thrombotic diseases, we investigated the relationship between hemostatic alterations and body fat distribution in subjects at risk for type 2 diabetes. SUBJECTS AND METHODS: Body fat distribution (visceral and subcutaneous abdominal adipose tissue) and liver fat content of 150 subjects with impaired glucose tolerance and/or impaired fasting glucose was determined using magnetic resonance imaging and spectroscopy. Participants underwent precise metabolic characterization and major hemostasis parameters were analyzed. RESULTS: Procoagulant factors (FII, FVII, FVIII and FIX) and anticoagulant proteins (antithrombin, protein C and protein S) were significantly associated with body fat distribution. In subjects with fatty liver, fibrinogen (298 mg/dl vs. 264 mg/dl, p=0.0182), FVII (99% vs. 90%, p=0.0049), FVIII (114% vs. 90 %, p=0.0098), protein C (124% vs. 111%, p=0.0006) and protein S (109% vs. 89%, p<0.0001) were higher than in controls. In contrast, antithrombin (97% vs. 102%, p=0.0025) was higher in control subjects. In multivariate analyses controlling for insulin sensitivity, body fat compartments and genotype variants (PNPLA3I148MM/MI/TM6SF2E167KK/KE), only protein C and protein S remained significantly increased in fatty liver. CONCLUSIONS: Body fat distribution is significantly associated with alterations of procoagulant as well as anticoagulant parameters. Liver fat plays a key role for the regulation of protein C and protein S suggesting a potential counteracting mechanism to the prothrombotic state in subjects with prediabetes and fatty liver. AU - Hörber, S. AU - Lehmann, R. AU - Stefan, N. AU - Machann, J. AU - Birkenfeld, A.L. AU - Wagner, R. AU - Heni, M. AU - Häring, H.-U. AU - Fritsche, A. AU - Peter, A. C1 - 62201 C2 - 50723 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Hemostatic alterations linked to body fat distribution, fatty liver and insulin resistance. JO - Mol. Metab. VL - 53 PB - Elsevier PY - 2021 SN - 2212-8778 ER - TY - JOUR AB - Technological advances have brought a steady increase in the availability of various types of omics data, from genomics to metabolomics. Integrating these multi-omics data is a chance and challenge for systems biology, yet tools to fully tap their potential remain scarce. We here present a fully unsupervised and versatile correlation-based method, termed Correlation guided Network Integration (CoNI), to integrate multi-omics data into a hypergraph structure that allows for the identification of effective modulators of metabolism. Our approach yields single transcripts of potential relevance that map to specific, densely connected metabolic sub-graphs or pathways. By applying our method on transcriptomics and metabolomics data from murine livers under standard Chow or high-fat diet, we identified eleven genes with potential regulatory effects on hepatic metabolism. Five candidates, including the hepatokine INHBE, were validated in human liver biopsies to correlate with diabetes-related traits such as overweight, hepatic fat content, and insulin resistance (HOMA-IR). Our method's successful application to an independent omics dataset confirmed that the novel CoNI framework is a transferable, entirely data-driven, flexible, and versatile tool for multiple omics data integration and interpretation. AU - Klaus, V. AU - Schriever, S.C. AU - Monroy Kuhn, J.M. AU - Peter, A. AU - Irmler, M. AU - Tokarz, J. AU - Prehn, C. AU - Kastenmüller, G. AU - Beckers, J. AU - Adamski, J. AU - Königsrainer, A.* AU - Müller, T.D. AU - Heni, M. AU - Tschöp, M.H. AU - Pfluger, P.T. AU - Lutter, D. C1 - 62566 C2 - 50812 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands SP - 101295 TI - Correlation guided Network Integration (CoNI) reveals novel genes affecting hepatic metabolism. JO - Mol. Metab. VL - 53 PB - Elsevier PY - 2021 SN - 2212-8778 ER - TY - JOUR AB - BACKGROUND: The global rise of metabolic disorders, such as obesity, diabetes type 2 and cardiovascular disease, demands a thorough molecular understanding of the cellular mechanisms that govern health or disease. The endoplasmic reticulum (ER) is a key organelle for cellular function and metabolic adaptation and, therefore, disturbed ER function, "ER stress", is a key feature of metabolic disorders. SCOPE OF REVIEW: As ER stress remains an ill-defined phenomenon, this review provides a general guide to understanding the nature, aetiology and consequences of ER stress in metabolic disorders. We define ER stress by its type of stressor, which is driven by proteotoxicity, lipotoxicity, and/or glucotoxicity. We discuss the implications of ER stress in metabolic disorders by reviewing evidence implicating ER phenotypes and organelle communication, protein quality control, calcium homeostasis, lipid and carbohydrate metabolism, and inflammation as key mechanisms in the development of ER stress and metabolic dysfunction. MAJOR CONCLUSIONS: In mammalian biology, ER is a phenotypically and functionally diverse platform for nutrient sensing, which is critical for cell-type specific metabolic control by e.g. hepatocytes, adipocytes, muscle cells, and neurons. In these cells, ER stress is a distinct, transient state of functional imbalance, which is usually resolved by the activation of adaptive programs such as the unfolded protein response (UPR), ER-associated protein degradation (ERAD), or autophagy. However, challenges to proteostasis also impact lipid and glucose metabolism and vice versa. In the ER, both sensing and adaptive measures are integrated and failure of the ER to adapt leads to aberrant metabolism, organelle dysfunction, insulin resistance, and inflammation. In conclusion, the ER is intricately linked to a wide spectrum of cellular functions and is a critical component in maintaining and restoring metabolic health. AU - Lemmer, I.L. AU - Willemsen, N.* AU - Hilal, N.* AU - Bartelt, A. C1 - 61059 C2 - 50023 TI - A guide to understanding endoplasmic reticulum stress in metabolic disorders. JO - Mol. Metab. VL - 47 PY - 2021 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: We aimed to assess the spatiotemporal GLP-1 and GIP receptor signaling, trafficking and recycling dynamics of GIPR mono-agonists, GLP-1R mono-agonists including semaglutide, and GLP-1/GIP dual-agonists MAR709 and tirzepatide. METHODS: Receptor G protein recruitment and internalization/trafficking dynamics were assessed using bioluminescence resonance energy transfer (BRET)-based technology and live cell HILO microscopy. RESULTS: Relative to the native and acylated GLP-1 agonists, MAR709 and tirzepatide show preserved maximal cAMP production despite partial Gαs recruitment paralleled by diminished ligand-induced receptor internalization at both target receptors. Despite MAR709's lower internalization rate, GLP-1R co-localization with Rab11-associated recycling endosomes was not different between MAR709 and GLP-1R specific mono-agonists. CONCLUSIONS: Our data indicate that MAR709 and tirzepatide induce unique spatiotemporal GLP-1 and GIP receptor signaling, trafficking and recycling dynamics relative to the native peptides, semaglutide and matched mono-agonist controls. These findings support the hypothesis that the structure of the GLP-1/GIP dual-agonists confer a biased agonism that, in addition to its influence on intracellular signaling, uniquely modulates receptor trafficking. AU - Novikoff, A. AU - O'Brien, S.L.* AU - Bernecker, M. AU - Grandl, G. AU - Kleinert, M. AU - Knerr, P.J.* AU - Stemmer, K. AU - Klingenspor, M.* AU - Zeigerer, A. AU - DiMarchi, R.* AU - Tschöp, M.H. AU - Finan, B.* AU - Calebiro, D.* AU - Müller, T.D. C1 - 61330 C2 - 50101 TI - Spatiotemporal GLP-1 and GIPR receptor signaling and trafficking/recycling dynamics induced by selected receptor mono- and dual-agonists. JO - Mol. Metab. VL - 49 PY - 2021 SN - 2212-8778 ER - TY - JOUR AB - While the effectiveness of bariatric surgery in restoring β-cell function has been described in type-2 diabetes (T2D) patients and animal models for years, the mechanistic underpinnings are largely unknown. The possibility of vertical sleeve gastrectomy (VSG) to rescue a clinically-relevant, late-stage T2D condition and to promote β-cell recovery has not been investigated on a single-cell level. Nevertheless, characterization of the heterogeneity and functional states of β-cells after VSG is a fundamental step to understand mechanisms of glycaemic recovery and to ultimately develop alternative, less-invasive therapies. Here, we report that VSG was superior to calorie restriction in late-stage T2D and rapidly restored normoglycaemia in morbidly obese and overt diabetic db/db mice. Single-cell profiling of islets of Langerhans showed that VSG induced distinct, intrinsic changes in the β-cell transcriptome, but not in that of α-, δ-, and PP-cells. VSG triggered fast β-cell redifferentiation and functional improvement within only two weeks of intervention, which is not seen upon calorie restriction. Furthermore, VSG expanded β-cell area by means of redifferentiation and by creating a proliferation competent β-cell state. Collectively, our study reveals the superiority of VSG in the remission of far-progressed T2D and presents paths of β-cell regeneration and molecular pathways underlying the glycaemic benefits of VSG. AU - Oppenländer, L. AU - Palit, S. AU - Stemmer, K. AU - Greisle, T. AU - Sterr, M. AU - Salinno, C. AU - Bastidas-Ponce, A. AU - Feuchtinger, A. AU - Böttcher, A. AU - Ansarullah AU - Theis, F.J. AU - Lickert, H. C1 - 62939 C2 - 51193 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Vertical sleeve gastrectomy triggers fast β-cell recovery upon overt diabetes. JO - Mol. Metab. VL - 54 PB - Elsevier PY - 2021 SN - 2212-8778 ER - TY - JOUR AB - Objective: Reorganization of the extracellular matrix is a prerequisite for healthy adipose tissue expansion, whereas fibrosis is a key feature of adipose dysfunction and inflammation. However, very little is known about the direct effects of impaired cell–matrix interaction in adipocyte function and insulin sensitivity. The objective of this study was to determine whether integrin activity can regulate insulin sensitivity in adipocytes and thereby systemic metabolism. Methods: We characterized integrin activity in adipose tissue and its consequences on whole-body metabolism using adipose-selective deletion of β1 integrin (Itgb1adipo-cre) and Kindlin-2 (Kind2adipo-cre) in mice. Results: We demonstrate that integrin signaling regulates white adipocyte insulin action and systemic metabolism. Consequently, loss of adipose integrin activity, similar to loss of adipose insulin receptors, results in a lipodystrophy-like phenotype and systemic insulin resistance. However, brown adipose tissue of Kind2adipo-cre and Itgb1adipo-cre mice is chronically hyperactivated and has increased substrate delivery, reduced endothelial basement membrane thickness, and increased endothelial vesicular transport. Conclusions: Thus, we establish integrin-extracellular matrix interactions as key regulators of white and brown adipose tissue function and whole-body metabolism. AU - Ruiz Ojeda, F.J. AU - Wang, J. AU - Bäcker, T. AU - Krueger, M.* AU - Zamani, S. AU - Rosowski, S. AU - Gruber, T. AU - Onogi, Y. AU - Feuchtinger, A. AU - Schulz, T.J.* AU - Fässler, R.* AU - Müller, T.D. AU - García-Cáceres, C. AU - Meier, M. AU - Blüher, M. AU - Ussar, S. C1 - 61010 C2 - 50014 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Active integrins regulate white adipose tissue insulin sensitivity and brown fat thermogenesis. JO - Mol. Metab. VL - 45 PB - Elsevier PY - 2021 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Islets of Langerhans contain heterogeneous populations of insulin-producing β-cells. Surface markers and respective antibodies for isolation, tracking, and analysis are urgently needed to study β-cell heterogeneity and explore the mechanisms to harness the regenerative potential of immature β-cells. METHODS: We performed single-cell mRNA profiling of early postnatal mouse islets and re-analyzed several single-cell mRNA sequencing datasets from mouse and human pancreas and islets. We used mouse primary islets, iPSC-derived endocrine cells, Min6 insulinoma, and human EndoC-βH1 β-cell lines and performed FAC sorting, Western blotting, and imaging to support and complement the findings from the data analyses. RESULTS: We found that all endocrine cell types expressed the cluster of differentiation 81 (CD81) during pancreas development, but the expression levels of this protein were gradually reduced in β-cells during postnatal maturation. Single-cell gene expression profiling and high-resolution imaging revealed an immature signature of β-cells expressing high levels of CD81 (CD81high) compared to a more mature population expressing no or low levels of this protein (CD81low/-). Analysis of β-cells from different diabetic mouse models and in vitro β-cell stress assays indicated an upregulation of CD81 expression levels in stressed and dedifferentiated β-cells. Similarly, CD81 was upregulated and marked stressed human β-cells in vitro. CONCLUSIONS: We identified CD81 as a novel surface marker that labels immature, stressed, and dedifferentiated β-cells in the adult mouse and human islets. This novel surface marker will allow us to better study β-cell heterogeneity in healthy subjects and diabetes progression. AU - Salinno, C. AU - Büttner, M. AU - Cota, P. AU - Tritschler, S. AU - Tarquis-Medina, M. AU - Bastidas-Ponce, A. AU - Scheibner, K. AU - Burtscher, I. AU - Böttcher, A. AU - Theis, F.J. AU - Bakhti, M. AU - Lickert, H. C1 - 61507 C2 - 50324 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - CD81 marks immature and dedifferentiated pancreatic β-cells. JO - Mol. Metab. VL - 49 PB - Elsevier PY - 2021 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Obesity is associated with low-grade adipose tissue inflammation and locally elevated levels of several glycoprotein 130 (gp130) cytokines. The conversion of white into brown-like adipocytes (browning) may increase energy expenditure and revert the positive energy balance that underlies obesity. Although different gp130 cytokines and their downstream targets were shown to regulate expression of the key browning marker uncoupling protein 1 (Ucp1), it remains largely unknown how this contributes to the development and maintenance of obesity. Herein, we aim to study the role of gp130 cytokine signaling in white adipose tissue (WAT) browning in the obese state. METHODS: Protein and gene expression levels of UCP1 and other thermogenic markers were assessed in a subcutaneous adipocyte cell line, adipose tissue depots from control or adipocyte-specific gp130 knockout (gp130Δadipo) mice fed either chow or a high-fat diet (HFD), or subcutaneous WAT biopsies from a human cohort of lean and obese subjects. WAT browning was modelled in vitro by exposing mature adipocytes to isoproterenol subsequent to stimulation with gp130 cytokines. ERK and JAK-STAT signaling were blocked using the inhibitors U0126 and Tofacitinib, respectively. RESULTS: Inguinal WAT of HFD-fed gp130Δadipo mice exhibited significantly elevated levels of UCP1 and other browning markers such as Cidea and Pgc-1α. In vitro, treatment with the gp130 cytokine oncostatin M (OSM) lowered isoproterenol-induced UCP1 protein and gene expression levels in a dose-dependent manner. Mechanistically, OSM mediated the inhibition of Ucp1 via the JAK-STAT but not the ERK pathway. In line with mouse data, OSM gene expression in human WAT positively correlated with BMI (r=0.284, p=0.021, n=66) and negatively with UCP1 expression (r=-0.413, p<0.001, n=66). CONCLUSIONS: Our data support the notion that OSM negatively regulates thermogenesis in WAT and, thus, may be an attractive target to treat obesity. AU - van Krieken, P.P.* AU - Odermatt, T.S.* AU - Borsigova, M.* AU - Blüher, M. AU - Wueest, S.* AU - Konrad, D.* C1 - 63028 C2 - 51220 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Oncostatin M suppresses browning of white adipocytes via gp130-STAT3 signaling. JO - Mol. Metab. VL - 54 PB - Elsevier PY - 2021 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Thyroid hormones (TH) are essential for the homeostatic control of energy metabolism and the regulation of body temperature. The hypothalamic-pituitary-thyroid (HPT) axis is regulated by negative feedback mechanisms ensuring that TH levels are maintained at a constant level. However, the feedback mechanisms underlying the resetting of HPT axis regulation in the control of body temperature are still not fully understood. Here, we aimed to determine the thermoregulatory response in hypothyroid mice to different environmental temperatures and the underlying mechanisms. METHODS: Distinct thermogenic challenges were induced in hypothyroid female C57BL/6N and leptin-deficient ob/ob mice through housing at either room temperature or thermoneutrality. Thermogenic and metabolic effects were analyzed through metabolic chambers, 18F-FDG-PET/MRI, infrared thermography, metabolic profiling, histology, gene expression and Wester Blot analysis. RESULTS: In hypothyroid mice maintained at room temperature, high leptin serum levels induce a pyrexic effect leading to the stabilization of body temperature through brown adipose tissue thermogenesis and white adipose tissue browning. Housing at thermoneutrality leads to a normalization of leptin levels and a reduction of the central temperature set-point resulting in decreased thermogenesis in brown and white adipose tissue and skeletal muscle and a significant decline in body temperature. Furthermore, anapyrexia in hypothyroid leptin deficient ob/ob mice indicates that besides its pyrexic actions, leptin confers a stimulatory effect on the HPT axis to stabilize remaining TH serum levels in hypothyroid mice. CONCLUSION: This study led to the identification of a previously unknown endocrine loop in which leptin acts in concert with the HPT axis to stabilize body temperature in hypothyroid mice. AU - Weiner, J.* AU - Roth, L.C.* AU - Kranz, M.* AU - Brust, P.* AU - Boelen, A.* AU - Klöting, N. AU - Heiker, J.T. AU - Blüher, M. AU - Tönjes, A.* AU - Pfluger, P.T. AU - Stumvoll, M. AU - Mittag, J.* AU - Krause, K.* C1 - 63169 C2 - 51403 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Leptin counteracts hypothermia in hypothyroidism through its pyrexic effects and by stabilizing serum thyroid hormone levels. JO - Mol. Metab. VL - 54 PB - Elsevier PY - 2021 SN - 2212-8778 ER - TY - JOUR AU - Zeigerer, A. C1 - 62531 C2 - 50778 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - NAFLD - A rising metabolic disease. JO - Mol. Metab. VL - 50 PB - Elsevier PY - 2021 SN - 2212-8778 ER - TY - JOUR AU - Bartke, T. AU - Schneider, R. C1 - 59002 C2 - 48479 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - You are what you eat-How nutrition and metabolism shape the genome through epigenetics. JO - Mol. Metab. VL - 38 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Background: Organisms can be primed by metabolic exposures to continue expressing response genes even once the metabolite is no longer available, and can affect the speed and magnitude of responsive gene expression during subsequent exposures. This “metabolic transcriptional memory” can have a profound impact on the survivability of organisms in fluctuating environments. Scope of review: Here I present several examples of metabolic transcriptional memory in the microbial world and discuss what is known so far regarding the underlying mechanisms, which mainly focus on chromatin modifications, protein inheritance, and broad changes in metabolic network. From these lessons learned in microbes, some insights into the yet understudied human metabolic memory can be gained. I thus discuss the implications of metabolic memory in disease progression in humans – i.e., the memory of high blood sugar exposure and the resulting effects on diabetic complications. Major conclusions: Carbon source shifts from glucose to other less preferred sugars such as lactose, galactose, and maltose for energy metabolism as well as starvation of a signal transduction precursor sugar inositol are well-studied examples of metabolic transcriptional memory in Escherichia coli and Saccharomyces cerevisiae. Although the specific factors guiding metabolic transcriptional memory are not necessarily conserved from microbes to humans, the same basic mechanisms are in play, as is observed in hyperglycemic memory. Exploration of new metabolic transcriptional memory systems as well as further detailed mechanistic analyses of known memory contexts in microbes is therefore central to understanding metabolic memory in humans, and may be of relevance for the successful treatment of the ever-growing epidemic of diabetes. AU - Bheda, P. C1 - 58948 C2 - 48587 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Metabolic transcriptional memory. JO - Mol. Metab. VL - 38 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Objective: Risk alleles for type 2 diabetes at the STARD10 locus are associated with lowered STARD10 expression in the beta-cell, impaired glucose-induced insulin secretion, and decreased circulating proinsulin:insulin ratios. Although likely to serve as a mediator of intracellular lipid transfer, the identity of the transported lipids and thus the pathways through which STARD10 regulates beta-cell function are not understood. The aim of this study was to identify the lipids transported and affected by STARD10 in the beta-cell and the role of the protein in controlling proinsulin processing and insulin granule biogenesis and maturation.Metkods: We used isolated islets from mice deleted selectively in the beta-cell for Stard10 (beta Stard10KO) and performed electron microscopy, pulse-chase, RNA sequencing, and lipidomic analyses. Proteomic analysis of STARD10 binding partners was executed in the INS1 (832/13) cell line. X-ray crystallography followed by molecular docking and lipid overlay assay was performed on purified STARD10 protein.Results: beta Stard10KO islets had a sharply altered dense core granule appearance, with a dramatic increase in the number of "rod-like" dense cores. Correspondingly, basal secretion of proinsulin was increased versus wild-type islets. The solution of the crystal structure of STARD10 to 2.3 angstrom resolution revealed a binding pocket capable of accommodating polyphosphoinositides, and STARD10 was shown to bind to inositides phosphorylated at the 3' position. Lipidomic analysis of beta Stard10KO islets demonstrated changes in phosphatidylinositol levels, and the inositol lipid kinase PIP4K2C was identified as a STARD10 binding partner. Also consistent with roles for STARD10 in phosphoinositide signalling, the phosphoinositide-binding proteins Pirt and Synaptotagmin 1 were amongst the differentially expressed genes in beta Stard10KO islets.Conclusion: Our data indicate that STARD10 binds to, and may transport, phosphatidylinositides, influencing membrane lipid composition, insulin granule biosynthesis, and insulin processing. AU - Carrat, G.R.* AU - Haythorne, E.* AU - Tomas, A.* AU - Haataja, L.* AU - Müller, A. AU - Arvan, P.* AU - Piunti, A.* AU - Cheng, K.* AU - Huang, M.* AU - Pullen, T.J.* AU - Georgiadou, E.* AU - Stylianides, T.* AU - Amirruddin, N.S.* AU - Salem, V.* AU - Distaso, W.* AU - Cakebread, A.* AU - Heesom, K.J.* AU - Lewis, P.A.* AU - Hodson, D.J.* AU - Briant, L.J.* AU - Fung, A.C.H.* AU - Sessions, R.B.* AU - Alpy, F.* AU - Kong, A.P.S.* AU - Benke, P.I.* AU - Torta, F.* AU - Teo, A.K.K.* AU - Leclerc, I.* AU - Solimena, M. AU - Wigley, D.B.* AU - Rutter, G.A.* C1 - 59467 C2 - 48864 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - The type 2 diabetes gene product STARD10 is a phosphoinositide-binding protein that controls insulin secretory granule biogenesis. JO - Mol. Metab. VL - 40 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Background: Individuals with diabetes are at a greater risk of hospitalization and mortality resulting from viral, bacterial, and fungal infections. The coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has spread quickly to more than 213 countries and claimed 395,779 lives as of June 7, 2020. Notably, in several studies, diabetes is one of the most reported comorbidities in patients with severe COVID-19.Scope of review: In this review, I summarize the clinical data on the risk for infectious diseases in individuals with diabetes while highlighting the mechanisms for altered immune regulation. The focus is on coronaviruses. Based on the new clinical data obtained from COVID-19 patients, a discussion of mechanisms, such as cytokine storm, pulmonary and endothelial dysfunction, and hypercoagulation, that may render individuals with diabetes more vulnerable to COVID-19 is provided.Major conclusions: Epidemiological studies show that poorly controlled diabetes is a risk factor for various infectious diseases. Given the global burden of diabetes and the pandemic nature of coronaviruses, understanding how diabetes affects COVID-19 severity is critical to designing tailored treatments and clinical management of individuals affected by diabetes. AU - Erener, S. C1 - 59598 C2 - 48871 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Diabetes, infection risk and COVID-19. JO - Mol. Metab. VL - 39 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Objective: Acute administration of the main protein component of high-density lipoprotein, apolipoprotein A-I (ApoA-1), improves glucose uptake in skeletal muscle. The molecular mechanisms mediating this are not known, but in muscle cell cultures, ApoA-1 failed to increase glucose uptake when infected with a dominant-negative AMP-activated protein kinase (AMPK) virus. We therefore investigated whether AMPK is necessary for ApoA-1-stimulated glucose uptake in intact heart and skeletal muscle in vivo.Methods: The effect of injection with recombinant human ApoA-1 (rApoA-1) on glucose tolerance, glucose-stimulated insulin secretion, and glucose uptake into skeletal and heart muscle with and without block of insulin secretion by injection of epinephrine (0.1 mg/kg) and propranolol (5 mg/kg), were investigated in 8 weeks high-fat diet-fed (60E%) wild-type and AMPK alpha(2) kinase-dead mice in the overnight-fasted state. In addition, the effect of rApoA-1 on glucose uptake in isolated skeletal muscle ex vivo was studied.Results: rApoA-1 lowered plasma glucose concentration by 1.7 mmol/l within 3 h (6.1 vs 4.4 mmol/l; p < 0.001). Three hours after rApoA-1 injection, glucose tolerance during a 40-min glucose tolerance test (GTT) was improved compared to control (area under the curve (AUC) reduced by 45%, p < 0.001). This was accompanied by an increased glucose clearance into skeletal (+110%; p < 0.001) and heart muscle (+100%; p < 0.001) and an increase in glucose-stimulated insulin secretion 20 min after glucose injection (+180%; p < 0.001). When insulin secretion was blocked during a GTT, rApoA-1 still enhanced glucose tolerance (AUC lowered by 20% compared to control; p < 0.001) and increased glucose clearance into skeletal (+50%; p < 0.05) and heart muscle (+270%; p < 0.001). These improvements occurred to a similar extent in both wild-type and AMPK alpha(2) kinase-dead mice and thus independently of AMPK alpha(2) activity in skeletal- and heart muscle. Interestingly, rApoA-1 failed to increase glucose uptake in isolated skeletal muscles ex vivo.Conclusions: In conclusion, ApoA-1 stimulates in vivo glucose disposal into skeletal and heart muscle independently of AMPK alpha(2). The observation that ApoA-1 fails to increase glucose uptake in isolated muscle ex vivo suggests that additional systemic effects are required. (C) 2020 The Author(s). Published by Elsevier GmbH. AU - Fritzen, A.M.* AU - Domingo-Espín, J.* AU - Lundsgaard, A.M.* AU - Kleinert, M. AU - Israelsen, I.* AU - Carl, C.S.* AU - Nicolaisen, T.S.* AU - Kjøbsted, R.* AU - Jeppesen, J.F.* AU - Wojtaszewski, J.F.P.* AU - Lagerstedt, J.O.* AU - Kiens, B.* C1 - 58655 C2 - 48592 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - ApoA-1 improves glucose tolerance by increasing glucose uptake into heart and skeletal muscle independently of AMPKα2. JO - Mol. Metab. VL - 35 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Objective: Fasting regimens can promote health, mitigate chronic immunological disorders, and improve age-related pathophysiological parameters in animals and humans. Several ongoing clinical trials are using fasting as a potential therapy for various conditions. Fasting alters metabolism by acting as a reset for energy homeostasis, but the molecular mechanisms underlying the beneficial effects of short-term fasting (STF) are not well understood, particularly at the systems or multiorgan level.Methods: We performed RNA-sequencing in nine organs from mice fed ad libitum (0 h) or subjected to fasting five times (2-22 h). We applied a combination of multivariate analysis, differential expression analysis, gene ontology, and network analysis for an in-depth understanding of the multiorgan transcriptome. We used literature mining solutions, LitLab (TM) and Gene Retriever (TM), to identify the biological and biochemical terms significantly associated with our experimental gene set, which provided additional support and meaning to the experimentally derived gene and inferred protein data.Results: We cataloged the transcriptional dynamics within and between organs during STF and discovered differential temporal effects of STF among organs. Using gene ontology enrichment analysis, we identified an organ network sharing 37 common biological pathways perturbed by STF. This network incorporates the brain, liver, interscapular brown adipose tissue, and posterior-subcutaneous white adipose tissue; hence, we named it the brain-liver-fats organ network. Using Reactome pathways analysis, we identified the immune system, dominated by T cell regulation processes, as a central and prominent target of systemic modulations during STF in this organ network. The changes we identified in specific immune components point to the priming of adaptive immunity and parallel the fine-tuning of innate immune signaling.Conclusions: Our study provides a comprehensive multiorgan transcriptomic profiling of mice subjected to multiple periods of STF and provides new insights into the molecular modulators involved in the systemic immunotranscriptomic changes that occur during short-term energy loss. AU - Huang, S.S.Y.* AU - Makhlouf, M.* AU - AbouMoussa, E.H.* AU - Ruiz Tejada Segura, M.L. AU - Mathew, L.S.* AU - Wang, K.* AU - Leung, M.C.* AU - Chaussabel, D.* AU - Logan, D.W.* AU - Scialdone, A. AU - Garand, M.* AU - Saraiva, L.R.* C1 - 59449 C2 - 48820 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Differential regulation of the immune system in a brain-liver-fats organ network during short-term fasting. JO - Mol. Metab. VL - 40 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Objective: Increasing energy expenditure through activation of brown adipose tissue (BAT) thermogenesis is an attractive approach to counteract obesity. It is therefore essential to understand the molecular mechanisms that control BAT functions. Until now several members of the Janus kinase (JAK) - signal transducer and activator of transcription (STAT) pathway have been implicated as being relevant for BAT physiology. However, whether the STAT family member STAT5 is important for the thermogenic property of adipose tissues is unknown. Therefore, we have investigated the role of STAT5 in thermogenic fat in this paper.Methods: We performed metabolic and molecular analyses using mice that harbor an adipocyte-specific deletion of Stat5a/b alleles.Results: We found that STAT5 is necessary for acute cold-induced temperature maintenance and the induction of lipid mobilization in BAT following beta(3)-adrenergic stimulation. Moreover, mitochondrial respiration of primary differentiated brown adipocytes lacking STAT5 was diminished. Increased sensitivity to cold stress upon STAT5 deficiency was associated with reduced expression of thermogenic markers including uncoupling protein 1 (UCP1), while decreased stimulated lipolysis was linked to decreased protein kinase A (PKA) activity. Additionally, brown remodeling of white adipose tissue was diminished following chronic beta(3)-adrenergic stimulation, which was accompanied by a decrease in mitochondrial performance.Conclusion: We conclude that STAT5 is essential for the functionality and the beta-adrenergic responsiveness of thermogenic adipose tissue. AU - Kaltenecker, D. AU - Spirk, K.* AU - Ruge, F.* AU - Grebien, F.* AU - Herling, M.* AU - Rupprecht, A.* AU - Kenner, L.* AU - Pohl, E.E.* AU - Mueller, K.M.* AU - Moriggl, R.* C1 - 59569 C2 - 48916 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - STAT5 is required for lipid breakdown and beta-adrenergic responsiveness of brown adipose tissue. JO - Mol. Metab. VL - 40 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Objective: The metabolic influence of gut microbiota plays a pivotal role in the pathogenesis of cardiometabolic diseases. Antibiotics affect intestinal bacterial diversity, and long-term usage has been identified as an independent risk factor for atherosclerosis-driven events. The aim of this study was to explore the interaction between gut dysbiosis by antibiotics and metabolic pathways with the impact on atherosclerosis development.Methods: We combined oral antibiotics with different diets in an Apolipoprotein E-knockout mouse model linking gut microbiota to atherosclerotic lesion development via an integrative cross-omics approach including serum metabolomics and cecal 16S rRNA targeted metagenomic sequencing. We further investigated patients with carotid atherosclerosis compared to control subjects with comparable cardiovascular risk.Results: Here, we show that increased atherosclerosis by antibiotics was connected to a loss of intestinal diversity and alterations of microbial metabolic functional capacity with a major impact on the host serum metabolome. Pathways that were modulated by antibiotics and connected to atherosclerosis included diminished tryptophan and disturbed lipid metabolism. These pathways were related to the reduction of certain members of Bacteroidetes and Clostridia by antibiotics in the gut. Patients with atherosclerosis presented a similar metabolic signature as those induced by antibiotics in our mouse model.Conclusion: Taken together, this work provides insights into the complex interaction between intestinal microbiota and host metabolism. Our data highlight that detrimental effects of antibiotics on the gut flora are connected to a pro-atherogenic metabolic phenotype beyond classical risk factors. AU - Kappel, B.A.* AU - De Angelis, L.* AU - Heiser, M.* AU - Ballanti, M.* AU - Stoehr, R.* AU - Goettsch, C.* AU - Mavilio, M.* AU - Artati, A. AU - Paoluzi, O.A.* AU - Adamski, J. AU - Mingrone, G.* AU - Staels, B.* AU - Burcelin, R.* AU - Monteleone, G.* AU - Menghini, R.* AU - Marx, N.* AU - Federici, M.* C1 - 58943 C2 - 48642 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Cross-omics analysis revealed gut microbiome-related metabolic pathways underlying atherosclerosis development after antibiotics treatment. JO - Mol. Metab. VL - 36 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Objective: Physical exercise training is associated with increased glucose uptake in skeletal muscle and improved glycemic control. HDAC5, a class IIa histone deacetylase, has been shown to regulate transcription of the insulin-responsive glucose transporter GLUT4 in cultured muscle cells. In this study, we analyzed the contribution of HDAC5 to the transcriptional network in muscle and the beneficial effect of muscle contraction and regular exercise on glucose metabolism. Methods: HDAC5 knockout mice (KO) and wild-type (WT) littermates were trained for 8 weeks on treadmills, metabolically phenotyped, and compared to sedentary controls. Hdac5-deficient skeletal muscle and cultured Hdac5-knockdown (KD) C2C12 myotubes were utilized for studies of gene expression and glucose metabolism. Chromatin immunoprecipitation (ChIP) studies were conducted to analyze Il6 promoter activity using H3K9ac and HDAC5 antibodies. Results: Global transcriptome analysis of Hdac5 KO gastrocnemius muscle demonstrated activation of the IL-6 signaling pathway. Accordingly, knockdown of Hdac5 in C2C12 myotubes led to higher expression and secretion of IL-6 with enhanced insulin-stimulated activation of AKT that was reversed by Il6 knockdown. Moreover, Hdac5-deficient myotubes exhibited enhanced glucose uptake, glycogen synthesis, and elevated expression levels of the glucose transporter GLUT4. Transcription of Il6 was further enhanced by electrical pulse stimulation in Hdac5-deficient C2C12 myotubes. ChIP identified a ∼1 kb fragment of the Il6 promoter that interacts with HDAC5 and demonstrated increased activation-associated histone marker AcH3K9 in Hdac5-deficient muscle cells. Exercise intervention of HDAC5 KO mice resulted in improved systemic glucose tolerance as compared to WT controls. Conclusions: We identified HDAC5 as a negative epigenetic regulator of IL-6 synthesis and release in skeletal muscle. HDAC5 may exert beneficial effects through two different mechanisms, transcriptional control of genes required for glucose disposal and utilization, and HDAC5-dependent IL-6 signaling cross-talk to improve glucose uptake in muscle in response to exercise. AU - Klymenko, O.* AU - Brecklinghaus, T.* AU - Dille, M.* AU - Springer, C.* AU - de Wendt, C.* AU - Altenhofen, D.* AU - Binsch, C.* AU - Knebel, B.* AU - Scheller, J.* AU - Hardt, C.* AU - Herwig, R.* AU - Chadt, A.* AU - Pfluger, P.T. AU - Al-Hasani, H.* AU - Kabra, D.G.* C1 - 60015 C2 - 49166 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Histone deacetylase 5 regulates interleukin 6 secretion and insulin action in skeletal muscle. JO - Mol. Metab. VL - 42 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Objectives: Typically, obesity results from an inappropriate balance between energy uptake from nutrient consumption and burning of calories, which leads to a pathological increase in fat mass. Obesity is a major cause of insulin resistance and diabetes. Inhibitory G proteins (G alpha(i)) form a subfamily that is involved in the regulation of adipose tissue function. Among the three Gai members, i.e. G alpha(i1), G alpha(i2), G alpha(i3), the G alpha(i2), protein is predominantly expressed in adipose tissue. However, the functions of the G alpha(i2) isoform in adipose tissue and its impact on the development of obesity are poorly understood.Methods: By using AdipoqCreER(T2) mice, we generated adipocyte-specific Gnai2-deficient mice to study G alpha(i2) function, specifically in white and brown adipocytes. These mice were fed either a control diet (CD) or a high fat diet (HFD). Mice were examined for obesity development, insulin resistance and glucose intolerance. We examined adipocyte morphology and the development of inflammation in the white adipose tissue. Finally, intracellular cAMP levels as an indicator of Gai signaling and glycerol release as an indicator of lipolysis rates were measured to verify the impact of G alpha(i2) on the signaling pathway in brown and white adipocytes.Results: An adipocyte-specific deficiency of G alpha(i2) significantly reduced diet-induced obesity, leading to decreased fat masses, smaller adipocytes and decreased inflammation in the white adipose tissue relative to littermate controls. Concurrently, oxygen consumption of brown adipocytes and in vivo measured energy expenditure were significantly enhanced. In addition, glucose tolerance and insulin sensitivity of HFD-fed adipocyte-specific Gnai2-deficient mice were improved compared to the respective controls. In the absence of G alpha(i2), adrenergic stimulation of intracellular adipocyte cAMP levels was increased, which correlated with increased lipolysis and energy expenditure.Conclusion: We conclude that adipocyte G alpha(i2) is a major regulator of adipocyte lipid content in diet-induced obesity by inhibiting adipocyte lipolysis in a cAMP-dependent manner resulting in increased energy expenditure. AU - Leiss, V.* AU - Schönsiegel, A.* AU - Gnad, T.* AU - Kerner, J.* AU - Kaur, J.* AU - Sartorius, T. AU - Machann, J. AU - Schick, F.* AU - Birnbaumer, L.* AU - Häring, H.U.* AU - Pfeifer, A.* AU - Nürnberg, B.* C1 - 59465 C2 - 48862 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Lack of Gαi2 proteins in adipocytes attenuates diet-induced obesity. JO - Mol. Metab. VL - 40 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Background: One of the fascinating aspects of epigenetic regulation is that it provides means to rapidly adapt to environmental change. This is particularly relevant in the plant kingdom, where most species are sessile and exposed to increasing habitat fluctuations due to global warming. Although the inheritance of epigenetically controlled traits acquired through environmental impact is a matter of debate, it is well documented that environmental cues lead to epigenetic changes, including chromatin modifications, that affect cell differentiation or are associated with plant acclimation and defense priming. Still, in most cases, the mechanisms involved are poorly understood. An emerging topic that promises to reveal new insights is the interaction between epigenetics and metabolism. Scope of review: This study reviews the links between metabolism and chromatin modification, in particular histone acetylation, histone methylation, and DNA methylation, in plants and compares them to examples from the mammalian field, where the relationship to human diseases has already generated a larger body of literature. This study particularly focuses on the role of reactive oxygen species (ROS) and nitric oxide (NO) in modulating metabolic pathways and gene activities that are involved in these chromatin modifications. As ROS and NO are hallmarks of stress responses, we predict that they are also pivotal in mediating chromatin dynamics during environmental responses. Major conclusions: Due to conservation of chromatin-modifying mechanisms, mammals and plants share a common dependence on metabolic intermediates that serve as cofactors for chromatin modifications. In addition, plant-specific non-CG methylation pathways are particularly sensitive to changes in folate-mediated one-carbon metabolism. Finally, reactive oxygen and nitrogen species may fine-tune epigenetic processes and include similar signaling mechanisms involved in environmental stress responses in plants as well as animals. AU - Lindermayr, C. AU - Rudolf, E.E. AU - Durner, J. AU - Groth, M. C1 - 58691 C2 - 48579 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Interactions between metabolism and chromatin in plant models. JO - Mol. Metab. VL - 38 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Objective: MicroRNAs (miRNAs) play an integral role in maintaining beta cell function and identity. Deciphering their targets and precise role, however, remains challenging. In this study, we aimed to identify miRNAs and their downstream targets involved in the regeneration of islet beta cells following partial pancreatectomy in mice.Methods: RNA from laser capture microdissected (LCM) islets of partially pancreatectomized and sham-operated mice were profiled with microarrays to identify putative miRNAs implicated in beta cell regeneration. Altered expression of the selected miRNAs, including miR-132, was verified by RT-PCR. Potential targets of miR-132 were selected through bioinformatic data mining. Predicted miR-132 targets were validated for their changed RNA, protein expression levels, and signaling upon miR-132 knockdown and/or overexpression in mouse MIN6 and human EndoC-beta H1 insulinoma cells. The ability of miR-132 to foster beta cell proliferation in vivo was further assessed in pancreatectomized miR-132(-/-) and control mice.Results: Partial pancreatectomy significantly increased the number of BrdU(+)/insulin(+) islet cells. Microarray profiling revealed that 14 miRNAs, including miR-132 and -141, were significantly upregulated in the LCM islets of the partially pancreatectomized mice compared to the LCM islets of the control mice. In the same comparison, miR-760 was the only downregulated miRNA. The changed expression of these miRNAs in the islets of the partially pancreatectomized mice was confirmed by RT-PCR only in the case of miR-132 and -141. Based on previous knowledge of its function, we focused our attention on miR-132. Downregulation of miR-132 reduced the proliferation of MIN6 cells while enhancing the levels of pro-apoptotic cleaved caspase-9. The opposite was observed in miR-132 overexpressing MIN6 cells. Microarray profiling, RT-PCR, and immunoblotting of the latter cells demonstrated their downregulated expression of Pten with concomitant increased levels of pro-proliferative factors phospho-Akt and phospho-Creb and inactivation of pro-apoptotic Foxo3a via its phosphorylation. Downregulation of Pten was further confirmed in the LCM islets of pancreatectomized mice compared to the sham-operated mice. Moreover, overexpression of miR-132 correlated with increased proliferation of EndoC-bH1 cells. The regeneration of beta cells following partial pancreatectomy was lower in the miR-132/212(-/-) mice than the control littermates.Conclusions: This study provides compelling evidence about the critical role of miR-132 for the regeneration of mouse islet beta cells through the downregulation of its target Pten. Hence, the miR-132/Pten/Akt/Foxo3 signaling pathway may represent a suitable target to enhance beta cell mass. AU - Mziaut, H. AU - Henniger, G.* AU - Ganss, K. AU - Hempel, S.* AU - Wolk, S.* AU - McChord, J.* AU - Chowdhury, K.* AU - Ravassard, P.* AU - Knoch, K.-P. AU - Krautz, C.* AU - Weitz, J.* AU - Grützmann, R.* AU - Pilarsky, C.* AU - Solimena, M. AU - Kersting, S. C1 - 57697 C2 - 47875 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands SP - 150-162 TI - MiR-132 controls pancreatic beta cell proliferation and survival through Pten/Akt/Foxo3 signaling. JO - Mol. Metab. VL - 31 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - The authors regret that the following sentence was published with an error. Correct sentence follows: “To this end, mice were fasted overnight and, after a basal blood sample was drawn, intraperitoneally injected with 1 mg/kg alanine solution in 0.9% saline.” should be corrected to “To this end, mice were fasted overnight and, after a basal blood sample was drawn, intraperitoneally injected with 1 g/kg alanine solution in 0.9% saline.” The authors would like to apologise for any inconvenience caused. AU - Okun, J.G.* AU - Conway, S.* AU - Schmidt, K.V.* AU - Schumacher, J.* AU - Wang, X.* AU - de Guia, R.* AU - Zota, A. AU - Klement, J.* AU - Seibert, O.* AU - Peters, A.* AU - Maida, A. AU - Herzig, S. AU - Rose, A.J.* C1 - 60036 C2 - 49820 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Molecular regulation of urea cycle function by the liver glucocorticoid receptor (vol 4, pg 732, 2015). JO - Mol. Metab. VL - 41 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Background: Imaging mass spectrometry enables in situ label-free detection of thousands of metabolites from intact tissue samples. However, automated steps for multi-omics analyses and interpretation of histological images have not yet been implemented in mass spectrometry data analysis workflows. The characterization of molecular properties within cellular and histological features is done via time-consuming, nonobjective, and irreproducible definitions of regions of interest, which are often accompanied by a loss of spatial resolution due to mass spectra averaging.Methods: We developed a new imaging pipeline called Spatial Correlation Image Analysis (SPACiAL), which is a computational multimodal workflow designed to combine molecular imaging data with multiplex immunohistochemistry (IHC). SPACiAL allows comprehensive and spatially resolved in situ correlation analyses on a cellular resolution. To demonstrate the method, matrix-assisted laser desorption-ionization (MALDI) Fourier-transform ion cyclotron resonance (FTICR) imaging mass spectrometry of metabolites and multiplex IHC staining were performed on the very same tissue section of mouse pancreatic islets and on human gastric cancer tissue specimens. The SPACiAL pipeline was used to perform an automatic, semantic-based, functional tissue annotation of histological and cellular features to identify metabolic profiles. Spatial correlation networks were generated to analyze metabolic heterogeneity associated with cellular features.Results: To demonstrate the new method, the SPACiAL pipeline was used to identify metabolic signatures of alpha and beta cells within islets of Langerhans, which are cell types that are not distinguishable via morphology alone. The semantic-based, functional tissue annotation allows an unprecedented analysis of metabolic heterogeneity via the generation of spatial correlation networks. Additionally, we demonstrated intra- and intertumoral metabolic heterogeneity within HER2/neu-positive and -negative gastric tumor cells.Conclusions: We developed the SPACiAL workflow to provide IHC-guided in situ metabolomics on intact tissue sections. Diminishing the workload by automated recognition of histological and functional features, the pipeline allows comprehensive analyses of metabolic heterogeneity. The multimodality of immunohistochemical staining and extensive molecular information from imaging mass spectrometry has the advantage of increasing both the efficiency and precision for spatially resolved analyses of specific cell types. The SPACiAL method is a stepping stone for the objective analysis of high-throughput, multi-omics data from clinical research and practice that is required for diagnostics, biomarker discovery, or therapy response prediction. AU - Prade, V.M. AU - Kunzke, T. AU - Feuchtinger, A. AU - Rohm, M. AU - Luber, B.* AU - Lordick, F.* AU - Buck, A. AU - Walch, A.K. C1 - 58824 C2 - 48623 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - De novo discovery of metabolic heterogeneity with immunophenotype-guided imaging mass spectrometry. JO - Mol. Metab. VL - 36 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Objective: The liver is a central target organ of growth hormone (GH), which stimulates the synthesis of insulin-like growth factor 1 (IGF1) and affects multiple biochemical pathways. A systematic multi-omics analysis of GH effects in the liver has not been performed. GH receptor (GHR) deficiency is a unique model for studying the consequences of lacking GH action. In this study, we used molecular profiling techniques to capture a broad spectrum of these effects in the liver of a clinically relevant large animal model for Laron syndrome.Methods: We performed holistic proteome and targeted metabolome analyses of liver samples from 6-month-old GHR-deficient (GHR-KO) pigs and GHR-expressing controls (four males, four females per group).Results: GHR deficiency resulted in an increased abundance of enzymes involved in amino acid degradation, in the urea cycle, and in the tricarboxylic acid cycle. A decreased ratio of long-chain acylcarnitines to free carnitine suggested reduced activity of carnitine palmitoyltransferase 1A and thus reduced mitochondrial import of fatty acids for beta-oxidation. Increased levels of short-chain acylcarnitines in the liver and in the circulation of GHR-KO pigs may result from impaired beta-oxidation of short-chain fatty acids or from increased degradation of specific amino acids. The concentration of mono-unsaturated glycerophosphocholines was significantly increased in the liver of GHR-KO pigs without morphological signs of steatosis, although the abundances of several proteins functionally linked to non-alcoholic fatty liver disease (fetuin B, retinol binding protein 4, several mitochondrial proteins) were increased. Moreover, GHR-deficient liver samples revealed distinct changes in the methionine and glutathione metabolic pathways, in particular, a significantly increased level of glycine N-methyltransferase and increased levels of total and free glutathione. Several proteins revealed a sex-related abundance difference in the control group but not in the GHR-KO group.Conclusions: Our integrated proteomics/targeted metabolomics study of GHR-deficient and control liver samples from a clinically relevant large animal model identified a spectrum of biological pathways that are significantly altered in the absence of GH action. Moreover, new insights into the role of GH in the sex-related specification of liver functions were provided. AU - Riedel, E.O.* AU - Hinrichs, A.* AU - Kemter, E.* AU - Dahlhoff, M.* AU - Backman, M.* AU - Rathkolb, B. AU - Prehn, C. AU - Adamski, J. AU - Renner, S.* AU - Blutke, A. AU - Hrabě de Angelis, M. AU - Bidlingmaier, M.* AU - Schopohl, J.* AU - Arnold, G.J.* AU - Fröhlich, T.* AU - Wolf, E.* C1 - 58596 C2 - 48177 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Functional changes of the liver in the absence of growth hormone (GH) action - Proteomic and metabolomic insights from a GH receptor deficient pig model. JO - Mol. Metab. VL - 36 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Objective: PPAR alpha/gamma dual agonists have been in clinical development for the treatment of metabolic diseases including type 2 diabetes and dyslipidemia. However, severe adverse side effects led to complications in clinical trials. As most of the beneficial effects rely on the compound activity in adipocytes, the selective targeting of this cell type is a cutting-edge strategy to develop safe anti-diabetic drugs. The goal of this study was to strengthen the adipocyte-specific uptake of the PPAR alpha/gamma agonist tesaglitazar via NPY1R-mediated internalization.Methods: NPY1R-preferring peptide tesaglitazar-[F-7, P-34]-NPY (tesa-NPY) was synthesized by a combination of automated SPPS and manual couplings. Following molecular and functional analyses for proof of concept, cell culture experiments were conducted to monitor the effects on adipogenesis. Mice treated with peptide drug conjugates or vehicle either by gavage or intraperitoneal injection were characterized phenotypically and metabolically. Histological analysis and transcriptional profiling of the adipose tissue were performed.Results: In vitro studies revealed that the tesaglitazar-[F-7, P-34]-NPY conjugate selectively activates PPAR gamma in NPY1R-expressing cells and enhances adipocyte differentiation and adiponectin expression in adipocyte precursor cells. In vivo studies using db/db mice demonstrated that the anti-diabetic activity of the peptide conjugate is as efficient as that of systemically administered tesaglitazar. Additionally, tesa-NPY induces adipocyte differentiation in vivo.Conclusions: The use of the tesaglitazar-[F7, P34]-NPY conjugate is a promising strategy to apply the beneficial PPAR alpha/gamma effects in adipocytes while potentially omitting adverse effects in other tissues. AU - Wittrisch, S.* AU - Klöting, N. AU - Mörl, K.* AU - Chakaroun, R. AU - Blüher, M. AU - Beck-Sickinger, A.G.* C1 - 57726 C2 - 47979 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands SP - 163-180 TI - NPY1R-targeted peptide-mediated delivery of a dual PPAR alpha/gamma agonist to adipocytes enhances adipogenesis and prevents diabetes progression. JO - Mol. Metab. VL - 31 PB - Elsevier PY - 2020 SN - 2212-8778 ER - TY - JOUR AB - Objective: The liver regulates the availability of insulin to other tissues and is the first line insulin response organ physiologically exposed to higher insulin concentrations than the periphery. Basal insulin during fasting inhibits hepatic gluconeogenesis and glycogenolysis, whereas postprandial insulin peaks stimulate glycogen synthesis. The molecular consequences of chronic insulin deficiency for the liver have not been studied systematically.Methods: We analyzed liver samples of a genetically diabetic pig model (MIDY) and of wild-type (WT) littermate controls by RNA sequencing, proteomics, and targeted metabolomics/lipidomics.Results: Cross-omics analyses revealed increased activities in amino acid metabolism, oxidation of fatty acids, ketogenesis, and gluconeogenesis in the MIDY samples. In particular, the concentrations of the ketogenic enzyme 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2) and of retinol dehydrogenase 16 (RDH16), which catalyzes the first step in retinoic acid biogenesis, were highly increased. Accordingly, elevated levels of retinoic acid, which stimulates the expression of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PCK1), were measured in the MIDY samples. In contrast, pathways related to extracellular matrix and inflammation/pathogen defense response were less active than in the WT samples.Conclusions: The first multi-omics study of a clinically relevant diabetic large animal model revealed molecular signatures and key drivers of functional alterations of the liver in insulin-deficient diabetes mellitus. The multi-omics data set provides a valuable resource for comparative analyses with other experimental or clinical data sets. (C) 2019 The Authors. Published by Elsevier GmbH. AU - Backman, M.* AU - Flenkenthaler, F.* AU - Blutke, A. AU - Dahlhoff, M.* AU - Ländström, E.* AU - Renner, S.* AU - Philippou-Massier, J.* AU - Krebs, S.* AU - Rathkolb, B. AU - Prehn, C. AU - Grzybek, M. AU - Coskun, Ü. AU - Rothe, M.* AU - Adamski, J. AU - Hrabě de Angelis, M. AU - Wanke, R.* AU - Fröhlich, T.* AU - Arnold, G.J.* AU - Blum, H.* AU - Wolf, E.* C1 - 56199 C2 - 46872 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands SP - 30-44 TI - Multi-omics insights into functional alterations of the liver in insulin-deficient diabetes mellitus. JO - Mol. Metab. VL - 26 PB - Elsevier PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Objective: Translation of basic research from bench-to-bedside relies on a better understanding of similarities and differences between mouse and human cell biology, tissue formation, and organogenesis. Thus, establishing ex vivo modeling systems of mouse and human pancreas development will help not only to understand evolutionary conserved mechanisms of differentiation and morphogenesis but also to understand pathomechanisms of disease and design strategies for tissue engineering.Methods: Here, we established a simple and reproducible Matrigel-based three-dimensional (3D) cyst culture model system of mouse and human pancreatic progenitors (PPs) to study pancreatic epithelialization and endocrinogenesis ex vivo. In addition, we reanalyzed previously reported single-cell RNA sequencing (scRNA-seq) of mouse and human pancreatic lineages to obtain a comprehensive picture of differential expression of key transcription factors (TFs), cell-cell adhesion molecules and cell polarity components in PPs during endocrinogenesis.Results: We generated mouse and human polarized pancreatic epithelial cysts derived from PPs. This system allowed to monitor establishment of pancreatic epithelial polarity and lumen formation in cellular and sub-cellular resolution in a dynamic time-resolved fashion. Furthermore, both mouse and human pancreatic cysts were able to differentiate towards the endocrine fate. This differentiation system together with scRNA-seq analysis revealed how apical-basal polarity and tight and adherens junctions change during endocrine differentiation.Conclusions: We have established a simple 3D pancreatic cyst culture system that allows to tempo-spatial resolve cellular and subcellular processes on the mechanistical level, which is otherwise not possible in vivo. AU - Bakhti, M. AU - Scheibner, K. AU - Tritschler, S. AU - Bastidas-Ponce, A. AU - Tarquis-Medina, M. AU - Theis, F.J. AU - Lickert, H. C1 - 57019 C2 - 47495 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands SP - 16-29 TI - Establishment of a high-resolution 3D modeling system for studying pancreatic epithelial cell biology in vitro. JO - Mol. Metab. VL - 30 PB - Elsevier PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - BACKGROUND: The availability of human pancreatic islets with characteristics closely resembling those present in vivo is instrumental for ex vivo studies in diabetes research. SCOPE OF REVIEW: In this review we propose metabolically phenotyped surgical patients as a novel source of pancreatic tissue for islet research. Laser Capture Microdissection from snap frozen surgical specimens is a relatively simple, reproducible and scalable method to isolate islets of highest purity for many types of "omics" analyses. Fresh pancreatic tissue slices enable the functional characterization of living islet cells in situ through dynamic experiments. Access to complete medical history and laboratory values for each donor offers the opportunity of direct correlations with different "omics" data and detailed metabolic profiling prior to pancreas surgery. Peripheral blood samples complete the picture of each patient and represent a platform for pursuit of biomarkers with uniquely comprehensive background information in regard to the donor's islet cells. MAJOR CONCLUSIONS: Living donors provide the scientific community with a steady and abundant supply of excellent material to study islets closest to their in situ environment, thus advancing our understanding of their physiology in health and diseases. AU - Barovic, M. AU - Distler, M.* AU - Schöniger, E. AU - Radisch, N. AU - Aust, D.* AU - Weitz, J.* AU - Ibberson, M.* AU - Schulte, A.M.* AU - Solimena, M. C1 - 57884 C2 - 47973 SP - S1-S6 TI - Metabolically phenotyped pancreatectomized patients as living donors for the study of islets in health and diabetes. JO - Mol. Metab. VL - 27 PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Objective: Obesity and type-2 diabetes (T2D) are metabolic diseases that represent a critical health problem worldwide. Metabolic disease is differentially associated with fat distribution, while visceral white adipose tissue (VAT) is particularly prone to obesity-associated inflammation. Next to their canonical function of immune suppression, regulatory T cells (Tregs) are key in controlling adipose tissue homeostasis. Towards understanding the molecular underpinnings of metabolic disease, we focus on how environmental-metabolic stimuli impinge on the functional interplay between Tregs and adipose tissue. Here, cold exposure or beta3-adrenergic signaling are a promising tool to increase energy expenditure by activating brown adipose tissue, as well as by reducing local inflammation within fat depots by supporting immunosuppressive Tregs. However, in humans, the underlying mechanisms that enable the environmental-immune crosstalk in the periphery and in the respective tissue remain currently unknown.Methods: We used combinatorial approaches of next generation humanized mouse models and in vitro and in vivo experiments together with beta3-adrenergic stimulation to dissect the underlying mechanisms of human Treg induction exposed to environmental stimuli such as cold. To test the translational relevance of our findings, we analyzed samples from the FREECE study in which human subjects were exposed to individualized cooling protocols. Samples were analyzed ex vivo and after in vitro Treg induction using qRT-PCR, immunofluorescence, as well as with multicolor flow cytometry and cell sorting.Results: In vivo application of the beta3-adrenergic receptor agonist mirabegron in humanized mice induced thermogenesis and improved the Treg induction capacity of naive T cells isolated from these animals. Using samples from the human FREECE study, we demonstrate that a short-term cold stimulus supports human Treg induction in vitro and in vivo. Mechanistically, we identify BORCS6 encoding the Ragulator-interacting protein C17orf59 to be significantly induced in human CD4(+) T cells upon short-term cold exposure. Strong mTOR signaling is known to limit successful Treg induction and thus likely by interfering with mTOR activation at lysosomal surfaces, C17orf59 improves the Treg induction capacity of human naive T cells upon cold exposure.Conclusions: These novel insights into the molecular underpinnings of human Treg induction suggest an important role of Tregs in linking environmental stimuli with adipose tissue function and metabolic diseases. Moreover, these discoveries shed new light on potential approaches towards tailored anti-inflammatory concepts that support human adipose tissue homeostasis by enabling Tregs. AU - Becker, M. AU - Serr, I. AU - Salb, V.K. AU - Ott, V. AU - Mengel, L.* AU - Blüher, M.* AU - Weigmann, B.* AU - Hauner, H.* AU - Tschöp, M.H. AU - Daniel, C. C1 - 56776 C2 - 47387 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands SP - 73-82 TI - Short-term cold exposure supports human Treg induction in vivo. JO - Mol. Metab. VL - 28 PB - Elsevier PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Background: It is now generally accepted that obesity is a major risk factor for type 2 diabetes mellitus (T2DM). Hepatic steatosis in particular, as well as visceral and ectopic fat accumulation within tissues, is associated with the development of the disease. We recently presented the first study on isolated human pancreatic adipocytes and their interaction with islets [Gerst, F., Wagner, R., Kaiser, G., Panse, M., Heni, M., Machann, J., et al., 2017. Metabolic crosstalk between fatty pancreas and fatty liver: effects on local inflammation and insulin secretion. Diabetologia 60(11): 2240-2251.]. The results indicate that the function of adipocytes depends on the overall metabolic status in humans which, in turn, differentially affects islet hormone release.Scope of Review: This review summarizes former and recent studies on factors derived from adipocytes and their effects on insulin-secreting beta-cells, with particular emphasis on the human pancreas. The adipocyte secretome is discussed with a special focus on its influence on insulin secretion, beta-cell survival and apoptotic beta-cell death.Major Conclusions: Human pancreatic adipocytes store lipids and release adipokines, metabolites, and pro-inflammatory molecules in response to the overall metabolic, humoral, and neuronal status. The differentially regulated adipocyte secretome impacts on endocrine function, i.e., insulin secretion, beta-cell survival and death which interferes with glycemic control. This review attempts to explain why the extent of pancreatic steatosis is associated with reduced insulin secretion in some studies but not in others. (C) 2019 The Authors. Published by Elsevier GmbH. AU - Gerst, F. AU - Wagner, R. AU - Oquendo, M.B.* AU - Siegel-Axel, D.I.* AU - Fritsche, A.* AU - Heni, M. AU - Staiger, H. AU - Häring, H.-U. AU - Ullrich, S. C1 - 56106 C2 - 46835 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 1-10 TI - What role do fat cells play in pancreatic tissue? JO - Mol. Metab. VL - 25 PB - Elsevier Science Bv PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Shotgun lipidomics enables an extensive analysis of lipids from tissues and fluids. Each specimen requires appropriate extraction and processing procedures to ensure good coverage and reproducible quantification of the lipidome. Adipose tissue (AT) has become a research focus with regard to its involvement in obesity-related pathologies. However, the quantification of the AT lipidome is particularly challenging due to the predominance of triacylglycerides, which elicit high ion suppression of the remaining lipid classes. METHODS: We present a new and validated method for shotgun lipidomics of AT, which tailors the lipid extraction procedure to the target specimen and features high reproducibility with a linear dynamic range of at least 4 orders of magnitude for all lipid classes. RESULTS: Utilizing this method, we observed tissue-specific and diet-related differences in three AT types (brown, gonadal, inguinal subcutaneous) from lean and obese mice. Brown AT exhibited a distinct lipidomic profile with the greatest lipid class diversity and responded to high-fat diet by altering its lipid composition, which shifted towards that of white AT. Moreover, diet-induced obesity promoted an overall remodeling of the lipidome, where all three AT types featured a significant increase in longer and more unsaturated triacylglyceride and phospholipid species. CONCLUSIONS: The here presented method facilitates reproducible systematic lipidomic profiling of AT and could be integrated with further -omics approaches used in (pre-) clinical research, in order to advance the understanding of the molecular metabolic dynamics involved in the pathogenesis of obesity-associated disorders. AU - Grzybek, M. AU - Palladini, A. AU - Alexaki, V.I.* AU - Surma, M.A.* AU - Simons, K.* AU - Chavakis, T. AU - Klose, C.* AU - Coskun, Ü. C1 - 55535 C2 - 46396 SP - 12-20 TI - Comprehensive and quantitative analysis of white and brown adipose tissue by shotgun lipidomics. JO - Mol. Metab. VL - 22 PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Objective: Obesity has been linked to an inflammation like state in the hypothalamus, mainly characterized by reactive gliosis (RG) of astrocytes and microglia. Here, using two diet models or pharmacological treatment, we assessed the effects of mild and drastic weight loss on RG, in the context of high-fat diet (HFD) induced obesity.Methods: We subjected HFD-induced obese (DIO) male C57BU6J mice to a weight loss intervention with a switch to standard chow, calorie restriction (CR), or treatment with the Glp1 receptor agonist Exendin-4 (EX4). The severity of RG was estimated by an ordinal scoring system based on fluorescence intensities of glial fibrillary acidic protein, ionized calcium-binding adapter molecule 1 positive (Iba1), cell numbers, and morphological characteristics.Results: In contrast to previous reports, DIO mice fed chronically with HFD showed no differences in microglial or astrocytic RG, compared to chow controls. Moreover, mild or profound weight loss had no impact on microglial RG. However, astrocyte RG was increased in CR and EX4 groups compared to chow fed animals and strongly correlated to body weight loss. Profound weight loss by either CR or EX4 was further linked to increased levels of circulating non-esterified free fatty acids.Conclusions: Overall, our data demonstrate that in a chronically obese state, astrocyte and microglial RG is indifferent from that observed in age-matched chow controls. Nonetheless, profound acute weight loss can induce astrocyte RG in the hypothalamic arcuate nucleus, possibly due to increased circulating NEFAs. This suggests that astrocytes may sense acute changes to both the dietary environment and body weight. AU - Harrison, L. AU - Pfuhlmann, K. AU - Schriever, S.C. AU - Pfluger, P.T. C1 - 55847 C2 - 46601 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 149-155 TI - Profound weight loss induces reactive astrogliosis in the arcuate nucleus of obese mice. JO - Mol. Metab. VL - 24 PB - Elsevier Science Bv PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Objective: The contribution of brown adipose tissue (BAT) to adult human metabolic control is a topic of ongoing investigation. In context, understanding the cellular events leading to BAT uncoupling, heat production, and energy expenditure is anticipated to produce significant insight into this endeavor. The phosphoinositide interacting regulator of transient receptor potentials (Pirt) was recently put forward as a key protein regulating cold sensing downstream of the transient receptor potential melastatin 8 (TRPM8). Notably, TRPM8 has been identified as a non-canonical regulator of BAT thermogenesis. The aim of this investigation was to delineate the role of Pirt in energy homeostasis and glucose metabolism - and the possible involvement of Pirt in TRPM8-elicited energy expenditure.Methods: To this end, we metabolically phenotyped male and female Pirt deficient (Pirt(-/-)) mice exposed to a low-fat chow diet or to a high-fat, high-sugar (HFHS) diet.Results: We identified that chow-fed female Pirt(-/-) mice have an increased susceptibility to develop obesity and glucose intolerance. This effect is abrogated when the mice are exposed to a HFHS diet. Conversely, Pirt(-/-) male mice display no metabolic phenotype on either diet relative to wild-type (WT) control mice. Finally, we observed that Pirt is dispensable for TRPM8-evoked energy expenditure.Conclusion: We here report subtle metabolic abnormalities in female, but not male, Pirt(-/-) mice. Future studies are required to tease out if metabolic stressors beyond dietary interventions, e.g. temperature fluctuations, are interacting with Pirt-signaling and metabolic control in a sex-specific fashion. AU - Jall, S. AU - Finan, B. AU - Collden, G. AU - Fischer, K. AU - Dong, X.* AU - Tschöp, M.H. AU - Müller, T.D. AU - Clemmensen, C. C1 - 55732 C2 - 46543 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 75-81 TI - Pirt deficiency has subtle female-specific effects on energy and glucose metabolism in mice. JO - Mol. Metab. VL - 23 PB - Elsevier Science Bv PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - In the Acknowledgements section under the listed funding sources, we erroneously stated that the work was supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program under grant agreement No 694968 (PREMSOT). The correct ERC funding source is instead: European Research Council ERC (AdG HypoFlam no. 695054). The authors apologize for this oversight. AU - Jall, S. AU - Finan, B. AU - Collden, G. AU - Fischer, K. AU - Dong, X.* AU - Tschöp, M.H. AU - Müller, T.D. AU - Clemmensen, C. C1 - 57434 C2 - 47778 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands TI - Pirt deficiency has subtle female-specific effects on energy and glucose metabolism in mice (vol 23, pg 75, 2019). JO - Mol. Metab. VL - 30 PB - Elsevier PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: The gut microbiota is an important influencing factor of metabolic health. Although dietary interventions with probiotics, prebiotics, and synbiotics can be effective means to regulate obesity and associated comorbidities, the underlying shifts in gut microbial communities, especially at the functional level, have not been characterized in great details. In this study, we sought to investigate the effects of synbiotics on the regulation of gut microbiota and the alleviation of high-fat diet (HFD)-induced metabolic disorders in mice. METHODS: Specific pathogen-free (SPF) male C57BL/6J mice were fed diets with either 10% (normal diet, ND) or 60% (high-fat diet, HFD) of total calories from fat (lard). Dietary interventions in the HFD-fed mice included (i) probiotic (Bifidobacterium animalis subsp. lactis and Lactobacillus paracasei subsp. paracasei DSM 46331), (ii) prebiotic (oat β-glucan), and (iii) synbiotic (a mixture of i and ii) treatments for 12 weeks. Besides detailed characterization of host metabolic parameters, a multi-omics approach was used to systematically profile the microbial signatures at both the phylogenetic and functional levels using 16S rRNA gene sequencing, metaproteomics and targeted metabolomics analysis. RESULTS: The synbiotic intervention significantly reduced body weight gain and alleviated features of metabolic complications. At the phylogenetic level, the synbiotic treatment significantly reversed HFD-induced changes in microbial populations, both in terms of richness and the relative abundance of specific taxa. Potentially important species such as Faecalibaculum rodentium and Alistipes putredinis that might mediate the beneficial effects of the synbiotic were identified. At the functional level, short-chain fatty acid and bile acid profiles revealed that all dietary interventions significantly restored cecal levels of acetate, propionate, and butyrate, while the synbiotic treatment reduced the bile acid pools most efficiently. Metaproteomics revealed that the effects of the synbiotic intervention might be mediated through metabolic pathways involved in carbohydrate, amino acid, and energy metabolisms. CONCLUSIONS: Our results suggested that dietary intervention using the novel synbiotic can alleviate HFD-induced weight gain and restore gut microbial ecosystem homeostasis phylogenetically and functionally. AU - Ke, X.* AU - Walker, A. AU - Haange, S.B.* AU - Lagkouvardos, I.* AU - Liu, Y.* AU - Schmitt-Kopplin, P. AU - von Bergen, M.* AU - Jehmlich, N.* AU - He, X.* AU - Clavel, T.* AU - Cheung, P.C.K.* C1 - 55559 C2 - 46225 SP - 96-109 TI - Synbiotic-driven improvement of metabolic disturbances is associated with changes in the gut microbiome in diet-induced obese mice. JO - Mol. Metab. VL - 22 PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Background/Objectives: Although the prevalence of obesity and its associated metabolic disorders is increasing in both sexes, the clinical phenotype differs between men and women, highlighting the need for individual treatment options. Mitochondrial dysfunction in various tissues, including white adipose tissue (WAT), has been accepted as a key factor for obesity-associated comorbidities such as diabetes. Given higher expression of mitochondria-related genes in the WAT of women, we hypothesized that gender differences in the bioenergetic profile of white (pre-) adipocytes from obese (age-and BMI-matched) donors must exist.Subjects/Methods: Using Seahorse technology, we measured oxygen consumption rates (OCR) and extracellular acidification rates (ECAR) of (pre-)adipocytes from male (n = 10) and female (n = 10) deeply-phenotyped obese donors under hypo-, normo- and hyperglycemic (0, 5 and 25 mM glucose) and insulin-stimulated conditions. Additionally, expression levels (mRNA/protein) of mitochondria-related genes (e.g. UQCRC2) and glycolytic enzymes (e.g. PKM2) were determined.Results: Dissecting cellular OCR and ECAR into different functional modules revealed that preadipocytes from female donors show significantly higher mitochondrial to glycolytic activity (higher OCR/ECAR ratio, p = 0.036), which is supported by a higher ratio of UQCRC2 to PKM2 mRNA levels (p = 0.021). However, no major gender differences are detectable in in vitro differentiated adipocytes (e.g. OCR/ECAR, p = 0.248). Importantly, glucose and insulin suppress mitochondrial activity (i.e. ATP-linked respiration) significantly only in preadipocytes of female donors, reflecting their trends towards higher insulin sensitivity.Conclusions: Collectively, we show that preadipocytes, but not in vitro differentiated adipocytes, represent a model system to reveal gender differences with clinical importance for metabolic disease status. In particular preadipocytes of females maintain enhanced mitochondrial flexibility, as demonstrated by pronounced responses of ATP-linked respiration to glucose. (C) 2018 The Authors. Published by Elsevier GmbH. AU - Keuper, M. AU - Berti, L. AU - Raedle, B. AU - Sachs, S. AU - Böhm, A. AU - Fritsche, L. AU - Fritsche, A. AU - Häring, H.-U. AU - Hrabě de Angelis, M. AU - Jastroch, M. AU - Hofmann, S.M. AU - Staiger, H. C1 - 54790 C2 - 45819 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 28-37 TI - Preadipocytes of obese humans display gender-specific bioenergetic responses to glucose and insulin. JO - Mol. Metab. VL - 20 PB - Elsevier Science Bv PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Objective: Genome wide association studies (GWAS) for type 2 diabetes (T2D) have identified genetic loci that often localise in non-coding regions of the genome, suggesting gene regulation effects. We combined genetic and transcriptomic analysis from human islets obtained from brain-dead organ donors or surgical patients to detect expression quantitative trait loci (eQTLs) and shed light into the regulatory mechanisms of these genes. Methods: Pancreatic islets were isolated either by laser capture microdissection (LCM) from surgical specimens of 103 metabolically phenotyped pancreatectomized patients (PPP) or by collagenase digestion of pancreas from 100 brain-dead organ donors (OD). Genotyping (> 8.7 million single nucleotide polymorphisms) and expression (> 47,000 transcripts and splice variants) analyses were combined to generate cis-eQTLs. Results: After applying genome-wide false discovery rate significance thresholds, we identified 1,173 and 1,021 eQTLs in samples of OD and PPP, respectively. Among the strongest eQTLs shared between OD and PPP were CHURC1 (OD p-value=1.71 × 10 -24 ; PPP p-value = 3.64 × 10 –24 ) and PSPH (OD p-value = 3.92 × 10 −26 ; PPP p-value = 3.64 × 10 −24 ). We identified eQTLs in linkage-disequilibrium with GWAS loci T2D and associated traits, including TTLL6, MLX and KIF9 loci, which do not implicate the nearest gene. We found in the PPP datasets 11 eQTL genes, which were differentially expressed in T2D and two genes (CYP4V2 and TSEN2) associated with HbA1c but none in the OD samples. Conclusions: eQTL analysis of LCM islets from PPP led us to identify novel genes which had not been previously linked to islet biology and T2D. The understanding gained from eQTL approaches, especially using surgical samples of living patients, provides a more accurate 3-dimensional representation than those from genetic studies alone. AU - Khamis, A.* AU - Canouil, M.* AU - Siddiq, A.* AU - Crouch, H.* AU - Falchi, M.* AU - Bulow, M.V.* AU - Ehehalt, F. AU - Marselli, L.* AU - Distler, M. AU - Richter, D. AU - Weitz, J. AU - Bokvist, K.* AU - Xenarios, I.* AU - Thorens, B.* AU - Schulte, A.M.* AU - Ibberson, M.* AU - Bonnefond, A.* AU - Marchetti, P.* AU - Solimena, M. AU - Froguel, P.* C1 - 55821 C2 - 46608 SP - 98-107 TI - Laser capture microdissection of human pancreatic islets reveals novel eQTLs associated with type 2 diabetes. JO - Mol. Metab. VL - 24 PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - In the Acknowledgements section we erroneously stated that M.H.T. has received support from the gs13:European Research Council under the European Union's Horizon 2020 research and innovation program under grant agreement No 694968 (PREMSOT). The correct funding source is instead: European Research Council ERC (AdG HypoFlam no. 695054). The authors apologize for this oversight. AU - Kleinert, M. AU - Kotzbeck, P.* AU - Altendorfer-Kroath, T.* AU - Birngruber, T.* AU - Tschöp, M.H. AU - Clemmensen, C. C1 - 57435 C2 - 47779 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands SP - 265-265 TI - Time-resolved hypothalamic open flow micro-perfusion reveals normal leptin transport across the blood-brain barrier in leptin resistant mice (vol 13, pg 77, 2018). JO - Mol. Metab. VL - 30 PB - Elsevier PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Objective: Although it is well established that a-calcitonin gene-related peptide (CGRP) stabilizes muscle-type cholinergic receptors nicotinic subunits (AChR), the underlying mechanism by which this neuropeptide regulates muscle protein metabolism and neuromuscular junction (NMJ) morphology is unclear.Methods: To elucidate the mechanisms how CGRP controls NMJ stability in denervated mice skeletal muscles, we carried out physiological, pharmacological, and molecular analyses of atrophic muscles induced by sciatic nerve transection.Results: Here, we report that CGRP treatment in vivo abrogated the deleterious effects on NMJ upon denervation (DEN), an effect that was associated with suppression of skeletal muscle proteolysis, but not stimulation of protein synthesis. CGRP also blocked the DEN-induced increase in endocytic AChR vesicles and the elevation of autophagosomes per NMJ area. The treatment of denervated animals with rapamycin blocked the stimulatory effects of CGRP on mTORC1 and its inhibitory actions on autophagic flux and NMJ degeneration. Furthermore, CGRP inhibited the DEN-induced hyperactivation of Ca2+-dependent proteolysis, a degradative system that has been shown to destabilize NMJ. Consistently, calpain was found to be activated by cholinergic stimulation in myotubes leading to the dispersal of AChR clusters, an effect that was abolished by CGRP.Conclusion: Taken together, these data suggest that the inhibitory effect of CGRP on autophagy and calpain may represent an important mechanism for the preservation of synapse morphology when degradative machinery is exacerbated upon denervation conditions. AU - Machado, J. AU - Silveira, W.A.* AU - Gonçalves, D.A.* AU - Schavinski, A.Z.* AU - Khan, M.M.* AU - Zanon, N.M.* AU - Berriel Diaz, M. AU - Rudolf, R.* AU - Kettelhut, I.C.* AU - Navegantes, L.C.* C1 - 56615 C2 - 47180 CY - Radarweg 29, 1043 Nx Amsterdam, Netherlands SP - 91-106 TI - alpha-Calcitonin gene-related peptide inhibits autophagy and calpain systems and maintains the stability of neuromuscular junction in denervated muscles. JO - Mol. Metab. VL - 28 PB - Elsevier PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Objective: Structurally-improved GIP analogs were developed to determine precisely whether GIP receptor (GIPR) agonism or antagonism lowers body weight in obese mice.Methods: A series of peptide-based GIP analogs, including structurally diverse agonists and a long-acting antagonist, were generated and characterized in vitro using functional assays in cell systems overexpressing human and mouse derived receptors. These analogs were characterized in vivo in DIO mice following acute dosing for effects on glycemic control, and following chronic dosing for effects on body weight and food intake. Pair-feeding studies and indirect calorimetry were used to survey the mechanism for body weight lowering. Congenital Gipr-/- and Glp1r-/- DIO mice were used to investigate the selectivity of the agonists and to ascribe the pharmacology to effects mediated by the GIPR.Results: Non-acylated, Aib2 substituted analogs derived from human GIP sequence showed full in vitro potency at human GIPR and subtly reduced in vitro potency at mouse GIPR without cross-reactivity at GLP-1R. These GIPR agonists lowered acute blood glucose in wild-type and Glp1r-/- mice, and this effect was absent in Gipr-/- mice, which confirmed selectivity towards GIPR. Chronic treatment of DIO mice resulted in modest yet consistent, dose-dependent decreased body weight across many studies with diverse analogs. The mechanism for body weight lowering is due to reductions in food intake, not energy expenditure, as suggested by pair-feeding studies and indirect calorimetry assessment. The weight lowering effect was preserved in DIO Glp-1r-/- mice and absent in DIO Gipr-/- mice. The body weight lowering efficacy of GIPR agonists was enhanced with analogs that exhibit higher mouse GIPR potency, with increased frequency of administration, and with fatty-acylated peptides of extended duration of action. Additionally, a fatty-acylated, N-terminally truncated GIP analog was shown to have high in vitro antagonism potency for human and mouse GIPR without cross-reactive activity at mouse GLP-1R or mouse glucagon receptor (GcgR). This acylated antagonist sufficiently inhibited the acute effects of GIP to improve glucose tolerance in DIO mice. Chronic treatment of DIO mice with high doses of this acylated GIPR antagonist did not result in body weight change. Further, co-treatment of this acylated GIPR antagonist with liraglutide, an acylated GLP-1R agonist, to DIO mice did not result in increased body weight lowering relative to liraglutide-treated mice. Enhanced body weight lowering in DIO mice was evident however following co-treatment of long-acting selective individual agonists for GLP-1R and GIPR, consistent with previous data.Conclusions: We conclude that peptide-based GIPR agonists, not peptide-based GIPR antagonists, that are suitably optimized for receptor selectivity, cross-species activity, and duration of action consistently lower body weight in DIO mice, although with moderate efficacy relative to GLP-1R agonists. These preclinical rodent pharmacology results, in accordance with recent clinical results, provide definitive proof that systemic GIPR agonism, not antagonism, is beneficial for body weight loss. (C) 2018 The Authors. Published by Elsevier GmbH. AU - Mroz, P.A.* AU - Finan, B. AU - Gelfanov, V.* AU - Yang, B.* AU - Tschöp, M.H. AU - DiMarchi, R.D.* AU - Perez-Tilve, D.* C1 - 55037 C2 - 46060 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 51-62 TI - Optimized GIP analogs promote body weight lowering in mice through GIPR agonism not antagonism. JO - Mol. Metab. VL - 20 PB - Elsevier Science Bv PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Background: The glucagon-like peptide-1 (GLP-1) is a multifaceted hormone with broad pharmacological potential. Among the numerous metabolic effects of GLP-1 are the glucose-dependent stimulation of insulin secretion, decrease of gastric emptying, inhibition of food intake, increase of natriuresis and diuresis, and modulation of rodent β-cell proliferation. GLP-1 also has cardio- and neuroprotective effects, decreases inflammation and apoptosis, and has implications for learning and memory, reward behavior, and palatability. Biochemically modified for enhanced potency and sustained action, GLP-1 receptor agonists are successfully in clinical use for the treatment of type-2 diabetes, and several GLP-1-based pharmacotherapies are in clinical evaluation for the treatment of obesity. Scope of review: In this review, we provide a detailed overview on the multifaceted nature of GLP-1 and its pharmacology and discuss its therapeutic implications on various diseases. Major conclusions: Since its discovery, GLP-1 has emerged as a pleiotropic hormone with a myriad of metabolic functions that go well beyond its classical identification as an incretin hormone. The numerous beneficial effects of GLP-1 render this hormone an interesting candidate for the development of pharmacotherapies to treat obesity, diabetes, and neurodegenerative disorders AU - Müller, T.D. AU - Finan, B.* AU - Bloom, S.R.* AU - D'Alessio, D.* AU - Drucker, D.J.* AU - Flatt, P.R.* AU - Fritsche, A. AU - Gribble, F.* AU - Grill, H.J.* AU - Habener, J.F.* AU - Holst, J.J.* AU - Langhans, W.* AU - Meier, J.J.* AU - Nauck, M.A.* AU - Perez-Tilve, D.* AU - Pocai, A.* AU - Reimann, F.* AU - Sandoval, D.A.* AU - Schwartz, T.W.* AU - Seeley, R.J.* AU - Stemmer, K. AU - Tang-Christensen, M.* AU - Woods, S.C.* AU - DiMarchi, R.D.* AU - Tschöp, M.H. C1 - 57145 C2 - 47553 SP - 72-130 TI - Glucagon-like peptide 1 (GLP-1). JO - Mol. Metab. VL - 30 PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - BACKGROUND: microRNAs (miRNAs) have emerged as critical contributors to immune regulation and homeostasis, and their dysregulation is involved in the aberrant differentiation and function of T cell subsets. In type 1 diabetes (T1D), the clinically overt disease is preceded by a presymptomatic phase which is marked by the presence of islet autoantibodies while the individual is still normoglycemic. Recent analyses revealed impaired regulatory T (Treg) cell induction from naive CD4+ T cells during this early phase of autoimmunity. SCOPE OF THE REVIEW: In this review article, we aim to discuss important recent insights into miRNA regulation of immune homeostasis and activation. Specifically, we highlight the role of miRNAs as biomarkers in autoimmunity and T1D as well as the contribution of specific miRNAs and their downstream pathways to the onset and progression of islet immunity. Furthermore, we focus on critical next steps required to establish miRNAs as biomarkers to predict disease onset and progression and as novel targets of future prevention and treatment strategies to control autoimmunity. MAJOR CONCLUSIONS: Several recent studies have provided considerable insight into the miRNA regulation of immune homeostasis and how dysregulated miRNAs contribute to onset and progression of islet autoimmunity. Specifically, high levels of individual miRNAs such as miR92a and miR181a are involved in impaired Treg induction during the onset of islet autoimmunity, thereby contributing to disease pathogenesis. The recent advancements in the field suggest miRNAs as potential biomarkers for islet autoimmunity and their direct targeting, especially in a T cell-specific manner, could contribute to the reestablishment of immune homeostasis and ultimately interfere with the onset of islet autoimmunity. AU - Scherm, M.G. AU - Serr, I. AU - Kaestner, K.H.* AU - Daniel, C. C1 - 57673 C2 - 47850 SP - S122-S128 TI - The role of T cell miRNAs for regulatory T cell induction in islet autoimmunity. JO - Mol. Metab. VL - 27S PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Objectives: Brown adipose tissue (BAT) dissipates nutritional energy as heat through uncoupling protein 1 (UCP1). The discovery of functional BAT in healthy adult humans has promoted the search for pharmacological interventions to recruit and activate brown fat as a treatment of obesity and diabetes type II. These efforts require in vivo models to compare the efficacy of novel compounds in a relevant physiological context.Methods: We generated a knock-in mouse line expressing firefly luciferase and near-infrared red florescent protein (iRFP713) driven by the regulatory elements of the endogenous Ucp1 gene.Results: Our detailed characterization revealed that firefly luciferase activity faithfully reports endogenous Ucp1 gene expression in response to physiological and pharmacological stimuli. The iRFP713 fluorescence signal was detected in the interscapular BAT region of cold-exposed reporter mice in an allele-dosage dependent manner. Using this reporter mouse model, we detected a higher browning capacity in female peri-ovarian white adipose tissue compared to male epididymal WAT, which we further corroborated by molecular and morphological features. In situ imaging detected a strong luciferase activity signal in a previously unappreciated adipose tissue depot adjunct to the femoral muscle, now adopted as femoral brown adipose tissue. In addition, screening cultured adipocytes by bioluminescence imaging identified the selective Salt-Inducible Kinase inhibitor, HG-9-91-01, to increase Ucp1 gene expression and mitochondrial respiration in brown and brite adipocytes.Conclusions: In our mouse model, firefly luciferase activity serves as a bona fide reporter for dynamic regulation of Ucp1. In addition, by means of iRFP713 we are able to monitor Ucp1 expression in a non-invasive fashion. (C) 2018 Published by Elsevier GmbH. AU - Wang, H.* AU - Willershäuser, M.* AU - Karlas, A.* AU - Gorpas, D. AU - Reber, J. AU - Ntziachristos, V. AU - Maurer, S.* AU - Fromme, T.* AU - Li, Y.* AU - Klingenspor, M.* C1 - 55041 C2 - 46037 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 14-27 TI - A dual Ucp1 reporter mouse model for imaging and quantitation of brown and brite fat recruitment. JO - Mol. Metab. VL - 20 PB - Elsevier Science Bv PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Hundreds of missense mutations in the coding region of PDX1 exist; however, if these mutations predispose to diabetes mellitus is unknown. METHODS: In this study, we screened a large cohort of subjects with increased risk for diabetes and identified two subjects with impaired glucose tolerance carrying common, heterozygous, missense mutations in the PDX1 coding region leading to single amino acid exchanges (P33T, C18R) in its transactivation domain. We generated iPSCs from patients with heterozygous PDX1, PDX1 mutations and engineered isogenic cell lines carrying homozygous PDX1, PDX1 mutations and a heterozygous PDX1 loss-of-function mutation (PDX1). RESULTS: Using an in vitro β-cell differentiation protocol, we demonstrated that both, heterozygous PDX1, PDX1 and homozygous PDX1, PDX1 mutations impair β-cell differentiation and function. Furthermore, PDX1 and PDX1 mutations reduced differentiation efficiency of pancreatic progenitors (PPs), due to downregulation of PDX1-bound genes, including transcription factors MNX1 and PDX1 as well as insulin resistance gene CES1. Additionally, both PDX1 and PDX1 mutations in PPs reduced the expression of PDX1-bound genes including the long-noncoding RNA, MEG3 and the imprinted gene NNAT, both involved in insulin synthesis and secretion. CONCLUSIONS: Our results reveal mechanistic details of how common coding mutations in PDX1 impair human pancreatic endocrine lineage formation and β-cell function and contribute to the predisposition for diabetes. AU - Wang, X. AU - Sterr, M. AU - Ansarullah AU - Burtscher, I. AU - Böttcher, A. AU - Beckenbauer, J. AU - Siehler, J. AU - Meitinger, T. AU - Häring, H.-U. AU - Staiger, H. AU - Cernilogar, F.M.* AU - Schotta, G.* AU - Irmler, M. AU - Beckers, J. AU - Wright, C.V.E.* AU - Bakhti, M. AU - Lickert, H. C1 - 55698 C2 - 46449 SP - 80-97 TI - Point mutations in the PDX1 transactivation domain impair human beta-cell development and function. JO - Mol. Metab. VL - 24 PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Objective: Extracellular matrix remodeling is required for adipose expansion under increased caloric intake. In turn, inhibited expandability due to aberrant collagen deposition promotes insulin resistance and progression towards the metabolic syndrome. An emerging role for the small leucine-rich proteoglycan Lumican in metabolically driven nonalcoholic fatty liver disease sparks an interest in further understanding its role in diet-induced obesity and metabolic complications.Methods: Whole body ablation of Lumican (Lum(-/-)) gene and adeno-associated virus-mediated over-expression were used in combination with control or high fat diet to assess energy balance, glucose homeostasis as well as adipose tissue health and remodeling.Results: Lumican was found to be particularly enriched in the stromal cells isolated from murine gonadal white adipose tissue. Likewise murine and human visceral fat showed a robust increase in Lumican as compared to fat from the subcutaneous depot. Lumican null female mice exhibited moderately increased fat mass, decreased insulin sensitivity and increased liver triglycerides in a diet-dependent manner. These changes coincided with inflammation in adipose tissue and no overt effects in adipose expandability, i.e. adipocyte formation and hypertrophy. Lumican over-expression in visceral fat and liver resulted in improved insulin sensitivity and glucose clearance.Conclusions: These data indicate that Lumican may represent a functional link between the extracellular matrix, glucose homeostasis, and features of the metabolic syndrome. (C) 2018 The Authors. Published by Elsevier GmbH. AU - Wolff, G.* AU - Taranko, A.E.* AU - Meln, I.* AU - Weinmann, J.* AU - Sijmonsma, T.* AU - Lerch, S.* AU - Heide, D.* AU - Billeter, A.T.* AU - Tews, D.* AU - Krunic, D.* AU - Fischer-Posovszky, P.* AU - Müller-Stich, B.P.* AU - Herzig, S. AU - Grimm, D.* AU - Heikenwälder, M.* AU - Kao, W.W.* AU - Vegiopoulos, A.* C1 - 54710 C2 - 45803 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 97-106 TI - Diet-dependent function of the extracellular matrix proteoglycan Lumican in obesity and glucose homeostasis. JO - Mol. Metab. VL - 19 PB - Elsevier Science Bv PY - 2019 SN - 2212-8778 ER - TY - JOUR AB - Objective: Although debated, metabolic health characterizes 10-25% of obese individuals and reduces risk of developing life-threatening comorbidities. Adipose tissue is a recognized endocrine organ important for the maintenance of whole-body metabolic health. Adipocyte transcriptional signatures of healthy and unhealthy obesity are largely unknown.Methods: Here, we used a small cohort of highly characterized obese individuals discordant for metabolic health, characterized their adipocytes transcriptional signatures, and cross-referenced them to mouse phenotypic and human GWAs databases.Results and conclusions: Our study showed that glucose intolerance and insulin resistance co-operate to remodel adipocyte transcriptome. We also identified the Nuclear Export Mediator Factor (NEMF) and the Ectoderm-Neural Cortex 1 (ENC1) as novel potential targets in the management of metabolic health in human obesity. (C) 2018 The Authors. Published by Elsevier GmbH. AU - Gerlini, R. AU - Berti, L. AU - Darr, J. AU - Lassi, M. AU - Brandmaier, S. AU - Fritsche, L. AU - Scheid, F. AU - Böhm, A. AU - Königsrainer, A.* AU - Grallert, H. AU - Häring, H.-U. AU - Hrabě de Angelis, M. AU - Staiger, H. AU - Teperino, R. C1 - 54396 C2 - 45506 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 42-50 TI - Glucose tolerance and insulin sensitivity define adipocyte transcriptional programs in human obesity. JO - Mol. Metab. VL - 18 PB - Elsevier Science Bv PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - Objective: Obesity and type 2 diabetes (T2D) arise from the interplay between genetic, epigenetic, and environmental factors. The aim of this study was to combine bioinformatics and functional studies to identify miRNAs that contribute to obesity and T2D.Methods: A computational framework (miR-QTL-Scan) was applied by combining QTL, miRNA prediction, and transcriptomics in order to enhance the power for the discovery of miRNAs as regulative elements. Expression of several miRNAs was analyzed in human adipose tissue and blood cells and miR-31 was manipulated in a human fat cell line.Results: In 17 partially overlapping QTL for obesity and T2D 170 miRNAs were identified. Four miRNAs (miR-15b, miR-30b, miR-31, miR-744) were recognized in gWAT (gonadal white adipose tissue) and six (miR-491, miR-455, miR-423-5p, miR-132-3p, miR-365-3p, miR-30b) in BAT (brown adipose tissue). To provide direct functional evidence for the achievement of the miR-QTL-Scan, miR-31 located in the obesity QTL Nob6 was experimentally analyzed. Its expression was higher in gWAT of obese and diabetic mice and humans than of lean controls. Accordingly, 10 potential target genes involved in insulin signaling and adipogenesis were suppressed. Manipulation of miR-31 in human SGBS adipocytes affected the expression of GLUT4, PPARg, IRS1, and ACACA. In human peripheral blood mononuclear cells (PBMC) miR-15b levels were correlated to baseline blood glucose concentrations and might be an indicator for diabetes.Conclusion: Thus, miR-QTL-Scan allowed the identification of novel miRNAs relevant for obesity and T2D. AU - Gottmann, P.* AU - Ouni, M.* AU - Sausenthaler, S.* AU - Roos, J.* AU - Stirm, L. AU - Jähnert, M.* AU - Kamitz, A.* AU - Hallahan, N.* AU - Jonas, W.* AU - Fritsche, A. AU - Häring, H.-U. AU - Staiger, H. AU - Blüher, M.* AU - Fischer-Posovszky, P.* AU - Vogel, H.* AU - Schürmann, A.* C1 - 53354 C2 - 44835 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 145-159 TI - A computational biology approach of a genome-wide screen connected miRNAs to obesity and type 2 diabetes. JO - Mol. Metab. VL - 11 PB - Elsevier Science Bv PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - Objective: Laron syndrome (LS) is a rare, autosomal recessive disorder in humans caused by loss-of-function mutations of the growth hormone receptor (GHR) gene. To establish a large animal model for LS, pigs with GHR knockout (KO) mutations were generated and characterized.Methods: CRISPR/Cas9 technology was applied to mutate exon 3 of the GHR gene in porcine zygotes. Two heterozygous founder sows with a 1bp or 7-bp insertion in GHR exon 3 were obtained, and their heterozygous F1 offspring were intercrossed to produce GHR-KO, heterozygous GHR mutant, and wild-type pigs. Since the latter two groups were not significantly different in any parameter investigated, they were pooled as the GHR expressing control group. The characterization program included body and organ growth, body composition, endocrine and clinical-chemical parameters, as well as signaling studies in liver tissue.Results: GHR-KO pigs lacked GHR and had markedly reduced serum insulin-like growth factor 1 (IGF1) levels and reduced IGF-binding protein 3 (IGFBP3) activity but increased IGFBP2 levels. Serum GH concentrations were significantly elevated compared with control pigs. GHR-KO pigs had a normal birth weight. Growth retardation became significant at the age of five weeks. At the age of six months, the body weight of GHR-KO pigs was reduced by 60% compared with controls. Most organ weights of GHR-KO pigs were reduced proportionally to body weight. However, the weights of liver, kidneys, and heart were disproportionately reduced, while the relative brain weight was almost doubled. GHR-KO pigs had a markedly increased percentage of total body fat relative to body weight and displayed transient juvenile hypoglycemia along with decreased serum triglyceride and cholesterol levels. Analysis of insulin receptor related signaling in the liver of adult fasted pigs revealed increased phosphorylation of IRS1 and PI3K. In agreement with the loss of GHR, phosphorylation of STAT5 was significantly reduced. In contrast, phosphorylation of JAK2 was significantly increased, possibly due to the increased serum leptin levels and increased hepatic leptin receptor expression and activation in GHR-KO pigs. In addition, increased mTOR phosphorylation was observed in GHR-KO liver samples, and phosphorylation studies of downstream substrates suggested the activation of mainly mTOR complex 2.Conclusion: GHR-KO pigs resemble the pathophysiology of LS and are an interesting model for mechanistic studies and treatment trials. AU - Hinrichs, A.* AU - Kessler, B.* AU - Kurome, M.* AU - Blutke, A.* AU - Kemter, E.* AU - Bernau, M.* AU - Scholz, A.M.* AU - Rathkolb, B.* AU - Renner, S.* AU - Bultmann, S.* AU - Leonhardt, H.* AU - Hrabě de Angelis, M. AU - Nagashima, H.* AU - Hoeflich, A.* AU - Blum, W.F.* AU - Bidlingmaier, M.* AU - Wanke, R.* AU - Dahlhoff, M.* AU - Wolf, E.* C1 - 53274 C2 - 44463 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 113-128 TI - Growth hormone receptor-deficient pigs resemble the pathophysiology of human Laron syndrome and reveal altered activation of signaling cascades in the liver. JO - Mol. Metab. VL - 11 PB - Elsevier Science Bv PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - Objective: Women with insulin-requiring gestational diabetes mellitus (GDM) are at high risk of developing diabetes within a few years postpartum. We implemented this phase II study to test the hypothesis that vildagliptin, a dipeptidyl peptidase-4 inhibitor, is superior to placebo in terms of reducing the risk of postpartum diabetes. Methods: Women with insulin-requiring GDM were randomized to either placebo or 50 mg vildagliptin twice daily for 24 months followed by a 12-month observation period (EudraCT: 2007-000634-39). Both groups received lifestyle counseling. The primary efficacy outcomes were the diagnosis of diabetes (American Diabetes Association (ADA) criteria) or impaired fasting glucose (IFG)/impaired glucose tolerance (IGT). Results: Between 2008 and 2015, 113 patients (58 vildagliptin, 55 placebo) were randomized within 2.2-10.4 (median 8.6) months after delivery. At the interim analysis, nine diabetic events and 28 IFG/IGT events had occurred. Fifty-two women withdrew before completing the treatment phase. Because of the low diabetes rate, the study was terminated. Lifestyle adherence was similar in both groups. At 24 months, the cumulative probability of postpartum diabetes was 3% and 5% (hazard ratio: 1.03; 95% confidence interval: 0.15-7.36) and IFG/IGT was 43% and 22% (hazard ratio: 0.55; 95% confidence interval: 0.26-1.19) in the placebo and vildagliptin groups, respectively. Vildagliptin was well tolerated with no unexpected adverse events. Conclusions: The study did not show significant superiority of vildagliptin over placebo in terms of reducing the risk of postpartum diabetes. However, treatment was safe and suggested some improvements in glycemic control, insulin resistance, and beta-cell function. The study identified critical issues in performing clinical trials in the early postpartum period in women with GDM hampering efficacy assessments. With this knowledge, we have set a basis for which properly powered trials could be performed in women with recent GDM. Trial registration number at ClinicalTrials.gov: NCT01018602. AU - Hummel, S. AU - Beyerlein, A. AU - Pfirrmann, M.* AU - Hofelich, A. AU - Much, D. AU - Hivner, S. AU - Bunk, M. AU - Herbst, M.* AU - Peplow, C. AU - Walter, M.* AU - Kohn, D.* AU - Hummel, N. AU - Kratzsch, J.* AU - Hummel, M.* AU - Füchtenbusch, M.* AU - Hasford, J.* AU - Ziegler, A.-G. C1 - 52883 C2 - 44621 CY - Amsterdam SP - 168-175 TI - Efficacy of vildagliptin for prevention of postpartum diabetes in women with a recent history of insulin-requiring gestational diabetes: A phase II, randomized, double-blind, placebo-controlled study. JO - Mol. Metab. VL - 9 PB - Elsevier Science Bv PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - Objective: The growth differentiation factor 15 (GDF15) is a stress-sensitive circulating factor that regulates systemic energy balance. Since exercise is a transient physiological stress that has pleiotropic effects on whole-body energy metabolism, we herein explored the effect of exercise on a) circulating GDF15 levels and b) GDF15 release from skeletal muscle in humans. Methods: Seven healthy males either rested or exercised at 67% of their VO2max for 1 h and blood was sampled from the femoral artery and femoral vein before, during, and after exercise. Plasma GDF15 concentrations were determined in these samples. Results: Plasma GDF15 levels increased 34% with exercise (p < 0.001) and further increased to 64% above resting values at 120 min (p < 0.001) after the cessation of exercise. There was no difference between the arterial and venous GDF15 concentration before, during, and after exercise. During a resting control trial, GDF15 levels measured in the same subjects were unaltered. Conclusions: Vigorous submaximal exercise increases circulating GDF15 levels in humans, but skeletal muscle tissue does not appear to be the source. AU - Kleinert, M. AU - Clemmensen, C.* AU - Sjøberg, K.A.* AU - Carl, C.S.* AU - Jeppesen, J.F.* AU - Wojtaszewski, J.F.P.* AU - Kiens, B.* AU - Richter, E.A.* C1 - 52880 C2 - 44598 CY - Amsterdam SP - 187-191 TI - Exercise increases circulating GDF15 in humans. JO - Mol. Metab. VL - 9 PB - Elsevier Science Bv PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - Objective: The inability of leptin to suppress food intake in diet-induced obesity, sometimes referred to as leptin resistance, is associated with several distinct pathological hallmarks. One prevailing theory is that impaired transport of leptin across the blood-brain barrier (BBB) represents a molecular mechanism that triggers this phenomenon. Recent evidence, however, has challenged this notion, suggesting that leptin BBB transport is acquired during leptin resistance.Methods: To resolve this debate, we utilized a novel cerebral Open Flow Microperfusion (cOFM) method to examine leptin BBB transport in male C57BL/6J mice, fed a chow diet or high fat diet (HFD) for 20 days.Results: Basal plasma leptin levels were 3.8-fold higher in HFD-fed mice (p < 0.05). Leptin administration (2.5 mg/kg) elicited similar pharmacokinetic profiles of circulating leptin. However, while leptin reduced food intake by 20% over 22 h in chow-fed mice, it did not affect food intake in HFD-fed mice. In spite of this striking functional difference, hypothalamic leptin levels, as measured by cOFM, did not differ between chow-fed mice and HFD-fed mice following leptin administration.Conclusions: These data suggest that leptin transport across the BBB is not impaired in non-obese leptin resistant mice and thus unlikely to play a direct role in the progression of pharmacological leptin resistance. AU - Kleinert, M. AU - Kotzbeck, P.* AU - Altendorfer-Kroath, T.* AU - Birngruber, T.* AU - Tschöp, M.H. AU - Clemmensen, C. C1 - 53512 C2 - 44895 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 77-82 TI - Time-resolved hypothalamic open flow micro-perfusion reveals normal leptin transport across the blood-brain barrier in leptin resistant mice. JO - Mol. Metab. VL - 13 PB - Elsevier Science Bv PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - Objective: Chronic ad libitum low protein-high carbohydrate diet (LPHC) increases health- and life-span in mice. A periodized (p) LPHC regimen would be a more practical long-term human lifestyle intervention, but the metabolic benefits of pLPHC are not known. Also, the interactions between LPHC diet and exercise training have not been investigated. Presently, we aimed to provide proof-of-concept data in mice of the efficacy of pLPHC and to explore the potential interactions with concurrent exercise training.Methods: A detailed phenotypic and molecular characterization of mice undergoing different durations of 14 d LPHC (5 E% protein)/14 d control diet cycles for up to 4 months with or without concurrent access to activity wheels allowing voluntary exercise training.Results: pLPHC conferred metabolic benefits similar to chronic LPHC, including increased FGF21 and adaptive thermogenesis, obesity-protection despite increased total energy intake and improved insulin sensitivity. The improved insulin sensitivity showed large fluctuations between diet periods and was lost within 14 days of switching back to control diet. Parallel exercise training improved weight maintenance but impaired the FGF21 response to pLPHC whereas repeated pLPHC cycles progressively augmented this response. Both the FGF21 suppression by exercise and potentiation by repeated cycles correlated tightly with Nupr1 mRNA in liver, suggesting dependence on liver integrated stress response.Conclusion: These results suggest that pLPHC may be a viable strategy to promote human health but also highlight the transient nature of the benefits and that the interaction with other lifestyle-interventions such as exercise training warrants consideration. (C) 2018 The Authors. Published by Elsevier GmbH. AU - Li, Z.* AU - Rasmussen, M.L.* AU - Li, J.* AU - Henriquez-Olguin, C.* AU - Knudsen, J.R.* AU - Madsen, A.B.* AU - Sánchez Quant, E.S. AU - Kleinert, M. AU - Jensen, T.E.* C1 - 54252 C2 - 45452 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 112-121 TI - Periodized low protein-high carbohydrate diet confers potent, but transient, metabolic improvements. JO - Mol. Metab. VL - 17 PB - Elsevier Science Bv PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - Background: To maintain homeostasis, cells need to coordinate the expression of their genes. Epigenetic mechanisms controlling transcription activation and repression include DNA methylation and post-translational modifications of histones, which can affect the architecture of chromatin and/or create 'docking platforms' for multiple binding proteins. These modifications can be dynamically set and removed by various enzymes that depend on the availability of key metabolites derived from different intracellular pathways. Therefore, small metabolites generated in anabolic and catabolic processes can integrate multiple external and internal stimuli and transfer information on the energetic state of a cell to the transcriptional machinery by regulating the activity of chromatin-modifying enzymes. Scope of review: This review provides an overview of the current literature and concepts on the connections and crosstalk between key cellular metabolites, enzymes responsible for their synthesis, recycling, and conversion and chromatin marks controlling gene expression. Major conclusions: Whereas current evidence indicates that many chromatin-modifying enzymes respond to alterations in the levels of their cofactors, cosubstrates, and inhibitors, the detailed molecular mechanisms and functional consequences of such processes are largely unresolved. A deeper investigation of mechanisms responsible for altering the total cellular concentration of particular metabolites, as well as their nuclear abundance and accessibility for chromatin-modifying enzymes, will be necessary to better understand the crosstalk between metabolism, chromatin marks, and gene expression. AU - Nieborak, A. AU - Schneider, R. C1 - 52882 C2 - 44620 TI - Metabolic intermediates - Cellular messengers talking to chromatin modifiers. JO - Mol. Metab. PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - © 2018 The Authors Objective: The worldwide prevalence of obesity has increased to 10% in men and 15% in women and is associated with severe comorbidities such as diabetes, cancer, and cardiovascular disease. Animal models of obesity are central to experimental studies of disease mechanisms and therapeutic strategies. Diet-induced obesity (DIO) models in rodents have provided important insights into the pathophysiology of obesity and, in most instances, are the first in line for exploratory pharmacology studies. To deepen the relevance towards translation to human patients, we established a corresponding DIO model in Göttingen minipigs (GM). Methods: Young adult female ovariectomized GM were fed a high-fat/high-energy diet for a period of 70 weeks. The ration was calculated to meet the requirements and maintain body weight (BW) of lean adult minipigs (L-GM group) or increased stepwise to achieve an obese state (DIO-GM group). Body composition, blood parameters and intravenous glucose tolerance were determined at regular intervals. A pilot chronic treatment trial with a GLP1 receptor agonist was conducted in DIO-GM. At the end of the study, the animals were necropsied and a biobank of selected tissues was established. Results: DIO-GM developed severe subcutaneous and visceral adiposity (body fat >50% of body mass vs. 22% in L-GM), increased plasma cholesterol, triglyceride, and free fatty acid levels, insulin resistance (HOMA-IR >5 vs. 2 in L-GM), impaired glucose tolerance and increased heart rate when resting and active. However, fasting glucose concentrations stayed within normal range throughout the study. Treatment with a long-acting GLP1 receptor agonist revealed substantial reduction of food intake and body weight within four weeks, with increased drug sensitivity relative to observations in other DIO animal models. Extensive adipose tissue inflammation and adipocyte necrosis was observed in visceral, but not subcutaneous, adipose tissue of DIO-GM. Conclusions: The Munich DIO-GM model resembles hallmarks of the human metabolic syndrome with extensive adipose tissue inflammation and adipocyte necrosis reported for the first time. DIO-GM may be used for evaluating novel treatments of obesity and associated comorbidities. They may help to identify triggers and mechanisms of fat tissue inflammation and mechanisms preventing complete metabolic decompensation despite morbid obesity. AU - Renner, S.* AU - Blutke, A.* AU - Dobenecker, B.* AU - Dhom, G.* AU - Müller, T.D. AU - Finan, B. AU - Clemmensen, C. AU - Bernau, M.* AU - Novak, I.* AU - Rathkolb, B. AU - Senf, S.* AU - Zöls, S.* AU - Roth, M.* AU - Götz, A. AU - Hofmann, S.M. AU - Hrabě de Angelis, M. AU - Wanke, R.* AU - Kienzle, E.* AU - Scholz, A.M.* AU - DiMarchi, R.* AU - Ritzmann, M.* AU - Tschöp, M.H. AU - Wolf, E.* C1 - 53746 C2 - 44992 TI - Metabolic syndrome and extensive adipose tissue inflammation in morbidly obese Göttingen minipigs. JO - Mol. Metab. PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - Objective: Diabetic retinopathy (DR) is induced by an accumulation of reactive metabolites such as ROS, RNS, and RCS species, which were reported to modulate the activity of cation channels of the TRPC family. In this study, we use Trpc1/4/5/6(-/-) compound knockout mice to analyze the contribution of these TRPC proteins to diabetic retinopathy. Methods: We used Nanostring- and qPCR-based analysis to determine mRNA levels of TRPC channels in control and diabetic retinae and retinal cell types. Chronic hyperglycemia was induced by Streptozotocin (STZ) treatment. To assess the development of diabetic retinopathy, vaso-regression, pericyte loss, and thickness of individual retinal layers were analyzed. Plasma and cellular methylglyoxal (MG) levels, as well as Glyoxalase 1 (GL01) enzyme activity and protein expression, were measured in WT and Trpc1/4/5/6(-/-) cells or tissues. MG-evoked toxicity in cells of both genotypes was compared by MTT assay. Results: We find that Trpc1/4/5/6(-/-) mice are protected from hyperglycemia-evoked vasoregression determined by the formation of acellular capillaries and pericyte drop-out. In addition, Trpc1/4/5/6(-/-) mice are resistant to the STZ-induced reduction in retinal layer thickness. The RCS metabolite methylglyoxal, which represents a key mediator for the development of diabetic retinopathy, was significantly reduced in plasma and red blood cells (RBCs) of STZ-treated Trpc1/4/5/6(-/-) mice compared to controls. GLO1 is the major MG detoxifying enzyme, and its activity and protein expression were significantly elevated in Trpc1/4/5/6-deficient cells, which led to significantly increased resistance to MG toxicity. GLO1 activity was also increased in retinal extracts from Trpc1/4/5/6(-/-) mice. The TRPCs investigated here are expressed at different levels in endothelial and glial cells of the retina. Conclusion: The protective phenotype in diabetic retinopathy observed in Trpc1/4/5/6(-/-) mice is suggestive of a predominant action of TRPCs in Muller cells and microglia because of their central position in the retention of a proper homoeostasis of the neurovascular unit. (C) 2018 The Authors. Published by Elsevier GmbH. AU - Sachdeva, R.* AU - Schlotterer, A.* AU - Schumacher, D.* AU - Matka, C.* AU - Mathar, I.* AU - Dietrich, N.* AU - Medert, R.* AU - Kriebs, U.* AU - Lin, J.* AU - Nawroth, P.P. AU - Birnbaumer, L.* AU - Fleming, T.* AU - Hammes, H.P.* AU - Freichel, M.* C1 - 52801 C2 - 44267 CY - Amsterdam SP - 156-167 TI - TRPC proteins contribute to development of diabetic retinopathy and regulate glyoxalase 1 activity and methylglyoxal accumulation. JO - Mol. Metab. VL - 9 PB - Elsevier Science Bv PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - Objectives: The deficit of Glyoxalase I (Glo1) and the subsequent increase in methylglyoxal (MG) has been reported to be one the five mechanisms by which hyperglycemia causes diabetic late complications. Aldo-keto reductases (AKR) have been shown to metabolize MG; however, the relative contribution of this superfamily to the detoxification of MG in vivo, particularly within the diabetic state, remains unknown.Methods: CRISPR/Cas9-mediated genome editing was used to generate a Glo1 knock-out (Glo1(-/-)) mouse line. Streptozotocin was then applied to investigate metabolic changes under hyperglycemic conditions.Results: Glo1(-/-) mice were viable and showed no elevated MG or MG-H1 levels under hyperglycemic conditions. It was subsequently found that the enzymatic efficiency of various oxidoreductases in the liver and kidney towards MG were increased in the Glo1(-/-) mice. The functional relevance of this was supported by the altered distribution of alternative detoxification products. Furthermore, it was shown that MG-dependent AKR activity is a potentially clinical relevant pathway in human patients suffering from diabetes.Conclusions: These data suggest that in the absence of GLO1, AKR can effectively compensate to prevent the accumulation of MG. The combination of metabolic, enzymatic, and genetic factors, therefore, may provide a better means of identifying patients who are at risk for the development of late complications caused by elevated levels of MG. (C) 2018 The Authors. Published by Elsevier GmbH. This is an open access article under the CC BY-NC-ND license. AU - Schumacher, D.* AU - Morgenstern, J.* AU - Oguchi, Y.* AU - Volk, N.* AU - Kopf, S.* AU - Groener, J.B.* AU - Nawroth, P.P. AU - Fleming, T.H.* AU - Freichel, M.* C1 - 54468 C2 - 45615 CY - Po Box 211, 1000 Ae Amsterdam, Netherlands SP - 143-152 TI - Compensatory mechanisms for methylglyoxal detoxification in experimental & clinical diabetes. JO - Mol. Metab. VL - 18 PB - Elsevier Science Bv PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: The metabolic role of d-serine, a non-proteinogenic NMDA receptor co-agonist, is poorly understood. Conversely, inhibition of pancreatic NMDA receptors as well as loss of the d-serine producing enzyme serine racemase have been shown to modulate insulin secretion. Thus, we aim to study the impact of chronic and acute d-serine supplementation on insulin secretion and other parameters of glucose homeostasis. METHODS: We apply MALDI FT-ICR mass spectrometry imaging, NMR based metabolomics, 16s rRNA gene sequencing of gut microbiota in combination with a detailed physiological characterization to unravel the metabolic action of d-serine in mice acutely and chronically treated with 1% d-serine in drinking water in combination with either chow or high fat diet feeding. Moreover, we identify SNPs in SRR, the enzyme converting L-to d-serine and two subunits of the NMDA receptor to associate with insulin secretion in humans, based on the analysis of 2760 non-diabetic Caucasian individuals. RESULTS: We show that chronic elevation of d-serine results in reduced high fat diet intake. In addition, d-serine leads to diet-independent hyperglycemia due to blunted insulin secretion from pancreatic beta cells. Inhibition of alpha 2-adrenergic receptors rapidly restores glycemia and glucose tolerance in d-serine supplemented mice. Moreover, we show that single nucleotide polymorphisms (SNPs) in SRR as well as in individual NMDAR subunits are associated with insulin secretion in humans. CONCLUSION: Thus, we identify a novel role of d-serine in regulating systemic glucose metabolism through modulating insulin secretion. AU - Suwandhi, L. AU - Hausmann, S. AU - Braun, A. AU - Gruber, T. AU - Heinzmann, S.S. AU - Gálvez, E.J.C.* AU - Buck, A. AU - Legutko, B. AU - Israel, A. AU - Feuchtinger, A. AU - Haythorne, E.* AU - Staiger, H. AU - Heni, M. AU - Häring, H.-U. AU - Schmitt-Kopplin, P. AU - Walch, A.K. AU - Cáceres, C.G.* AU - Tschöp, M.H. AU - Rutter, G.A.* AU - Strowig, T.* AU - Elsner, M. AU - Ussar, S. C1 - 54117 C2 - 45361 TI - Chronic d-serine supplementation impairs insulin secretion. JO - Mol. Metab. PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - Objective: Energy metabolism is challenged upon nutrient stress, eventually leading to a variety of metabolic diseases that represent a major global health burden. Methods: Here, we combine quantitative mitochondrial respirometry (Seahorse technology) and proteomics (LC-MS/MS-based total protein approach) to understand how molecular changes translate to changes in mitochondrial energy transduction during diet-induced obesity (DIO) in the liver. Results: The integrative analysis reveals that significantly increased palmitoyl-carnitine respiration is supported by an array of proteins enriching lipid metabolism pathways. Upstream of the respiratory chain, the increased capacity for ATP synthesis during DIO associates strongest to mitochondrial uptake of pyruvate, which is routed towards carboxylation. At the respiratory chain, robust increases of complex I are uncovered by cumulative analysis of single subunit concentrations. Specifically, nuclear-encoded accessory subunits, but not mitochondrial-encoded or core units, appear to be permissive for enhanced lipid oxidation. Conclusion: Our integrative analysis, that we dubbed "respiromics", represents an effective tool to link molecular changes to functional mechanisms in liver energy metabolism, and, more generally, can be applied for mitochondria! analysis in a variety of metabolic and mitochondrial disease models. (C) 2018 The Authors. Published by Elsevier GmbH. AU - Walheim, E. AU - Wiśniewski, J.R.* AU - Jastroch, M. C1 - 52774 C2 - 44299 CY - Amsterdam SP - 4-14 TI - Respiromics - An integrative analysis linking mitochondrial bioenergetics to molecular signatures. JO - Mol. Metab. VL - 9 PB - Elsevier Science Bv PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - Objective: Homozygous loss-of-function mutations in the gene coding for the homeobox transcription factor (TF) PDX1 leads to pancreatic agenesis, whereas heterozygous mutations can cause Maturity-Onset Diabetes of the Young 4 (MODY4). Although the function of Pdx1 is well studied in pre-clinical models during insulin-producing beta-cell development and homeostasis, it remains elusive how this TF controls human pancreas development by regulating a downstream transcriptional program. Also, comparative studies of PDX1 binding patterns in pancreatic progenitors and adult beta-cells have not been conducted so far. Furthermore, many studies reported the association between single nucleotide polymorphisms (SNPs) and T2DM, and it has been shown that islet enhancers are enriched in T2DM-associated SNPs. Whether regions, harboring T2DM-associated SNPs are PDX1 bound and active at the pancreatic progenitor stage has not been reported so far. Methods: In this study, we have generated a novel induced pluripotent stem cell (iPSC) line that efficiently differentiates into human pancreatic progenitors (PPs). Furthermore, PDX1 and H3K27ac chromatin immunoprecipitation sequencing (ChIP-seq) was used to identify PDX1 transcriptional targets and active enhancer and promoter regions. To address potential differences in the function of PDX1 during development and adulthood, we compared PDX1 binding profiles from PPs and adult islets. Moreover, combining ChIP-seq and GWAS meta-analysis data we identified T2DM-associated SNPs in PDX1 binding sites and active chromatin regions. Results: ChIP-seq for PDX1 revealed a total of 8088 PDX1-bound regions that map to 5664 genes in iPSC-derived PPs. The PDX1 target regions include important pancreatic TFs, such as PDX1 itself, RFX6, HNF1B, and ME1S1, which were activated during the differentiation process as revealed by the active chromatin mark H3K27ac and mRNA expression profiling, suggesting that auto-regulatory feedback regulation maintains PDX1 expression and initiates a pancreatic TF program. Remarkably, we identified several PDX1 target genes that have not been reported in the literature in human so far, including RFX3, required for ciliogenesis and endocrine differentiation in mouse, and the ligand of the Notch receptor DLL1, which is important for endocrine induction and tip-trunk patterning. The comparison of PDX1 profiles from PPs and adult human islets identified sets of stage-specific target genes, associated with early pancreas development and adult beta-cell function, respectively. Furthermore, we found an enrichment of T2DM-associated SNPs in active chromatin regions from iPSC-derived PPs. Two of these SNPs fall into PDX1 occupied sites that are located in the intronic regions of TCF7L2 and HNF1B. Both of these genes are key transcriptional regulators of endocrine induction and mutations in cis-regulatory regions predispose to diabetes. Conclusions: Our data provide stage-specific target genes of PDX1 during in vitro differentiation of stem cells into pancreatic progenitors that could be useful to identify pathways and molecular targets that predispose for diabetes. In addition, we show that T2DM-associated SNPs are enriched in active chromatin regions at the pancreatic progenitor stage, suggesting that the susceptibility to T2DM might originate from imperfect execution of a beta-cell developmental program. AU - Wang, X. AU - Sterr, M. AU - Burtscher, I. AU - Chen, S.* AU - Hieronimus, A. AU - Machicao, F. AU - Staiger, H. AU - Häring, H.-U. AU - Lederer, G. AU - Meitinger, T. AU - Cernilogar, F.M.* AU - Schotta, G.* AU - Irmler, M. AU - Beckers, J. AU - Hrabě de Angelis, M. AU - Ray, M.* AU - Wright, C.V.E.* AU - Bakhti, M. AU - Lickert, H. C1 - 52884 C2 - 44555 CY - Amsterdam SP - 57-68 TI - Genome-wide analysis of PDX1 target genes in human pancreatic progenitors. JO - Mol. Metab. VL - 9 PB - Elsevier Science Bv PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Obesity is strongly linked to genes regulating neuronal signaling and function, implicating the central nervous system in the maintenance of body weight and energy metabolism. Genome-wide association studies identified significant associations between body mass index (BMI) and multiple loci near Cell adhesion molecule2 (CADM2), which encodes a mediator of synaptic signaling enriched in the brain. Here we sought to further understand the role of Cadm2 in the pathogenesis of hyperglycemia and weight gain. METHODS: We first analyzed Cadm2 expression in the brain of both human subjects and mouse models and subsequently characterized a loss-of-function mouse model of Cadm2 for alterations in glucose and energy homeostasis. RESULTS: We show that the risk variant rs13078960 associates with increased CADM2 expression in the hypothalamus of human subjects. Increased Cadm2 expression in several brain regions of Lepob/ob mice was ameliorated after leptin treatment. Deletion of Cadm2 in obese mice (Cadm2/ob) resulted in reduced adiposity, systemic glucose levels, and improved insulin sensitivity. Cadm2-deficient mice exhibited increased locomotor activity, energy expenditure rate, and core body temperature identifying Cadm2 as a potent regulator of systemic energy homeostasis. CONCLUSIONS: Together these data illustrate that reducing Cadm2 expression can reverse several traits associated with the metabolic syndrome including obesity, insulin resistance, and impaired glucose homeostasis. AU - Yan, X.* AU - Wang, Z.* AU - Schmidt, V.* AU - Gauert, A.* AU - Willnow, T.E.* AU - Heinig, M. AU - Poy, M.N.* C1 - 52509 C2 - 44049 SP - 180-188 TI - Cadm2 regulates body weight and energy homeostasis in mice. JO - Mol. Metab. VL - 8 PY - 2018 SN - 2212-8778 ER - TY - JOUR AB - Objective: The transcription factors (TF) Foxa2 and Pdx1 are key regulators of beta-cell (β-cell) development and function. Mutations of these TFs or their respective cis-regulatory consensus binding sites have been linked to maturity diabetes of the young (MODY), pancreas agenesis, or diabetes susceptibility in human. Although Foxa2 has been shown to directly regulate Pdx1 expression during mouse embryonic development, the impact of this gene regulatory interaction on postnatal β-cell maturation remains obscure. Methods: In order to easily monitor the expression domains of Foxa2 and Pdx1 and analyze their functional interconnection, we generated a novel double knock-in homozygous (FVFPBFDHom) fluorescent reporter mouse model by crossing the previously described Foxa2-Venus fusion (FVF) with the newly generated Pdx1-BFP (blue fluorescent protein) fusion (PBF) mice. Results: Although adult PBF homozygous animals exhibited a reduction in expression levels of Pdx1, they are normoglycemic. On the contrary, despite normal pancreas and endocrine development, the FVFPBFDHom reporter male animals developed hyperglycemia at weaning age and displayed a reduction in Pdx1 levels in islets, which coincided with alterations in β-cell number and islet architecture. The failure to establish mature β-cells resulted in loss of β-cell identity and trans-differentiation towards other endocrine cell fates. Further analysis suggested that Foxa2 and Pdx1 genetically and functionally cooperate to regulate maturation of adult β-cells. Conclusions: Our data show that the maturation of pancreatic β-cells requires the cooperative function of Foxa2 and Pdx1. Understanding the postnatal gene regulatory network of β-cell maturation will help to decipher pathomechanisms of diabetes and identify triggers to regenerate dedifferentiated β-cell mass. AU - Bastidas-Ponce, A. AU - Roscioni, S. AU - Burtscher, I. AU - Bader, E. AU - Sterr, M. AU - Bakhti, M. AU - Lickert, H. C1 - 50944 C2 - 42978 CY - Amsterdam SP - 524-534 TI - Foxa2 and Pdx1 cooperatively regulate postnatal maturation of pancreatic β-cells. JO - Mol. Metab. VL - 6 IS - 6 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Increased hepatic expression of dipeptidyl peptidase 4 (DPP4) is associated with non-alcoholic fatty liver disease (NAFLD). Whether this is causative for the development of NAFLD is not yet clarified. Here we investigate the effect of hepatic DPP4 overexpression on the development of liver steatosis in a mouse model of diet-induced obesity. METHODS: Plasma DPP4 activity of subjects with or without NAFLD was analyzed. Wild-type (WT) and liver-specific Dpp4 transgenic mice (Dpp4-Liv-Tg) were fed a high-fat diet and characterized for body weight, body composition, hepatic fat content and insulin sensitivity. In vitro experiments on HepG2 cells and primary mouse hepatocytes were conducted to validate cell autonomous effects of DPP4 on lipid storage and insulin sensitivity. RESULTS: Subjects suffering from insulin resistance and NAFLD show an increased plasma DPP4 activity when compared to healthy controls. Analysis of Dpp4-Liv-Tg mice revealed elevated systemic DPP4 activity and diminished active GLP-1 levels. They furthermore show increased body weight, fat mass, adipose tissue inflammation, hepatic steatosis, liver damage and hypercholesterolemia. These effects were accompanied by increased expression of PPARγ and CD36 as well as severe insulin resistance in the liver. In agreement, treatment of HepG2 cells and primary hepatocytes with physiological concentrations of DPP4 resulted in impaired insulin sensitivity independent of lipid content. CONCLUSIONS: Our results give evidence that elevated expression of DPP4 in the liver promotes NAFLD and insulin resistance. This is linked to reduced levels of active GLP-1, but also to auto- and paracrine effects of DPP4 on hepatic insulin signaling. AU - Baumeier, C.* AU - Schlüter, L.* AU - Saussenthaler, S.* AU - Laeger, T.* AU - Rödiger, M.* AU - Alaze, S.A.* AU - Fritsche, L. AU - Häring, H.-U. AU - Stefan, N. AU - Fritsche, A. AU - Schwenk, R.W.* AU - Schürmann, A.* C1 - 52124 C2 - 43728 CY - Amsterdam SP - 1254-1263 TI - Elevated hepatic DPP4 activity promotes insulin resistance and non-alcoholic fatty liver disease. JO - Mol. Metab. VL - 6 IS - 10 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Objective: The prevalence of diabetes mellitus and associated complications is steadily increasing. As a resource for studying systemic consequences of chronic insulin insufficiency and hyperglycemia, we established a comprehensive biobank of long-term diabetic INS C94Y transgenic pigs, a model of mutant INS gene-induced diabetes of youth (MIDY), and of wild-type (WT) littermates. Methods: Female MIDY pigs (n = 4) were maintained with suboptimal insulin treatment for 2 years, together with female WT littermates (n = 5). Plasma insulin, C-peptide and glucagon levels were regularly determined using specific immunoassays. In addition, clinical chemical, targeted metabolomics, and lipidomics analyses were performed. At age 2 years, all pigs were euthanized, necropsied, and a broad spectrum of tissues was taken by systematic uniform random sampling procedures. Total beta cell volume was determined by stereological methods. A pilot proteome analysis of pancreas, liver, and kidney cortex was performed by label free proteomics. Results: MIDY pigs had elevated fasting plasma glucose and fructosamine concentrations, C-peptide levels that decreased with age and were undetectable at 2 years, and an 82% reduced total beta cell volume compared to WT. Plasma glucagon and beta hydroxybutyrate levels of MIDY pigs were chronically elevated, reflecting hallmarks of poorly controlled diabetes in humans. In total, ∼1900 samples of different body fluids (blood, serum, plasma, urine, cerebrospinal fluid, and synovial fluid) as well as ∼17,000 samples from ∼50 different tissues and organs were preserved to facilitate a plethora of morphological and molecular analyses. Principal component analyses of plasma targeted metabolomics and lipidomics data and of proteome profiles from pancreas, liver, and kidney cortex clearly separated MIDY and WT samples. Conclusions: The broad spectrum of well-defined biosamples in the Munich MIDY Pig Biobank that will be available to the scientific community provides a unique resource for systematic studies of organ crosstalk in diabetes in a multi-organ, multi-omics dimension. AU - Blutke, A.* AU - Renner, S.* AU - Flenkenthaler, F.* AU - Backman, M.* AU - Haesner, S.* AU - Kemter, E.* AU - Ländström, E.* AU - Braun-Reichhart, C.* AU - Albl, B.* AU - Streckel, E.* AU - Rathkolb, B. AU - Prehn, C. AU - Palladini, A. AU - Grzybek, M. AU - Krebs, S.* AU - Bauersachs, S.* AU - Bähr, A.* AU - Brühschwein, A.* AU - Deeg, C.A.* AU - De Monte, E.* AU - Dmochewitz, M.* AU - Eberle, C.* AU - Emrich, D.* AU - Fux, R.* AU - Groth, F.* AU - Gumbert, S.* AU - Heitmann, A.* AU - Hinrichs, A.S.* AU - Keßler, B.* AU - Kurome, M.* AU - Leipig-Rudolph, M.* AU - Matiasek, K.* AU - Öztürk, H.* AU - Otzdorff, C.* AU - Reichenbach, M.* AU - Reichenbach, H.D.* AU - Rieger, A.* AU - Rieseberg, B.* AU - Rosati, M.* AU - Saucedo, M.N.* AU - Schleicher, A.* AU - Schneider, M.R.* AU - Simmet, K.* AU - Steinmetz, J.* AU - Übel, N.* AU - Zehetmaier, P.* AU - Jung, A.* AU - Adamski, J. AU - Coskun, Ü. AU - Hrabě de Angelis, M. AU - Simmet, C.* AU - Ritzmann, M.* AU - Meyer-Lindenberg, A.* AU - Blum, H.* AU - Arnold, G.J.* AU - Fröhlich, T.* AU - Wanke, R.* AU - Wolf, E.* C1 - 51454 C2 - 43186 CY - Amsterdam SP - 931-940 TI - The Munich MIDY Pig Biobank - A unique resource for studying organ crosstalk in diabetes. JO - Mol. Metab. VL - 6 IS - 8 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Background: Plasma insulin levels are predominantly the product of the morphological mass of insulin producing beta cells in the pancreatic islets of Langerhans and the functional status of each of these beta cells. Thus, deficiency in either beta cell mass or function, or both, can lead to insufficient levels of insulin, resulting in hyperglycemia and diabetes. Nonetheless, the precise contribution of beta cell mass and function to the pathogenesis of diabetes as well as the underlying mechanisms are still unclear. In the past, this was largely due to the restricted number of technologies suitable for studying the scarcely accessible human beta cells. However, in recent years, a number of new platforms have been established to expand the available techniques and to facilitate deeper insight into the role of human beta cell mass and function as cause for diabetes and as potential treatment targets. Scope of Review: This review discusses the current knowledge about contribution of human beta cell mass and function to different stages of type 1 and type 2 diabetes pathogenesis. Furthermore, it highlights standard and newly developed technological platforms for the study of human beta cell biology, which can be used to increase our understanding of beta cell mass and function in human glucose homeostasis. Major Conclusions: In contrast to early disease models, recent studies suggest that in type 1 and type 2 diabetes impairment of beta cell function is an early feature of disease pathogenesis while a substantial decrease in beta cell mass occurs more closely to clinical manifestation. This suggests that, in addition to beta cell mass replacement for late stage therapies, the development of novel strategies for protection and recovery of beta cell function could be most promising for successful diabetes treatment and prevention. The use of today's developing and wide range of technologies and platforms for the study of human beta cells will allow for a more detailed investigation of the underlying mechanisms and will facilitate development of treatment approaches to specifically target human beta cell mass and function. AU - Chen, C. AU - Cohrs, C.M. AU - Stertmann, J. AU - Bozsak, R. AU - Speier, S. C1 - 51623 C2 - 43326 CY - Amsterdam SP - 943-957 TI - Human beta cell mass and function in diabetes: Recent advances in knowledge and technologies to understand disease pathogenesis. JO - Mol. Metab. VL - 6 IS - 9 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Objective Recently, we have shown that Bezafibrate (BEZ), the pan-PPAR (peroxisome proliferator-activated receptor) activator, ameliorated diabetes in insulin deficient streptozotocin treated diabetic mice. In order to study whether BEZ can also improve glucose metabolism in a mouse model for fatty liver and type 2 diabetes, the drug was applied to TallyHo mice. Methods TallyHo mice were divided into an early (ED) and late (LD) diabetes progression group and both groups were treated with 0.5% BEZ (BEZ group) or standard diet (SD group) for 8 weeks. We analyzed plasma parameters, pancreatic beta-cell morphology, and mass as well as glucose metabolism of the BEZ-treated and control mice. Furthermore, liver fat content and composition as well as hepatic gluconeogenesis and mitochondrial mass were determined. Results Plasma lipid and glucose levels were markedly reduced upon BEZ treatment, which was accompanied by elevated insulin sensitivity index as well as glucose tolerance, respectively. BEZ increased islet area in the pancreas. Furthermore, BEZ treatment improved energy expenditure and metabolic flexibility. In the liver, BEZ ameliorated steatosis, modified lipid composition and increased mitochondrial mass, which was accompanied by reduced hepatic gluconeogenesis. Conclusions Our data showed that BEZ ameliorates diabetes probably via reduced steatosis, enhanced hepatic mitochondrial mass, improved metabolic flexibility and elevated hepatic insulin sensitivity in TallyHo mice, suggesting that BEZ treatment could be beneficial for patients with NAFLD and impaired glucose metabolism. AU - Frankó, A. AU - Neschen, S. AU - Rozman, J. AU - Rathkolb, B. AU - Aichler, M. AU - Feuchtinger, A. AU - Brachthäuser, L. AU - Neff, F. AU - Kovarova, M.* AU - Wolf, E.* AU - Fuchs, H. AU - Häring, H.-U. AU - Peter, A. AU - Hrabě de Angelis, M. C1 - 50246 C2 - 42201 SP - 256-266 TI - Bezafibrate ameliorates diabetes via reduced steatosis and improved hepatic insulin sensitivity in diabetic TallyHo mice. JO - Mol. Metab. VL - 6 IS - 3 PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Objective: The hypothalamus of hypercaloric diet-induced obese animals is featured by a significant increase of microglial reactivity and its associated cytokine production. However, the role of dietary components, in particular fat and carbohydrate, with respect to the hypothalamic inflammatory response and the consequent impact on hypothalamic control of energy homeostasis is yet not clear. Methods: We dissected the different effects of high-carbohydrate high-fat (HCHF) diets and low-carbohydrate high-fat (LCHF) diets on hypothalamic inflammatory responses in neurons and non-neuronal cells and tested the hypothesis that HCHF diets induce hypothalamic inflammation via advanced glycation end-products (AGEs) using mice lacking advanced glycation end-products (AGEs) receptor (RAGE) and/or the activated leukocyte cell-adhesion molecule (ALCAM). Results: We found that consumption of HCHF diets, but not of LCHF diets, increases microgliosis as well as the presence of N(ε)-(Carboxymethyl)-Lysine (CML), a major AGE, in POMC and NPY neurons of the arcuate nucleus. Neuron-secreted CML binds to both RAGE and ALCAM, which are expressed on endothelial cells, microglia, and pericytes. On a HCHF diet, mice lacking the RAGE and ALCAM genes displayed less microglial reactivity and less neovasculature formation in the hypothalamic ARC, and this was associated with significant improvements of metabolic disorders induced by the HCHF diet. Conclusions: Combined overconsumption of fat and sugar, but not the overconsumption of fat per se, leads to excessive CML production in hypothalamic neurons, which, in turn, stimulates hypothalamic inflammatory responses such as microgliosis and eventually leads to neuronal dysfunction in the control of energy metabolism. AU - Gao, Y. AU - Bielohuby, M.* AU - Fleming, T.* AU - Grabner, G.F.* AU - Foppen, E.* AU - Bernhard, W.* AU - Guzmán-Ruiz, M.* AU - Layritz, C. AU - Legutko, B. AU - Zinser, E.* AU - García-Cáceres, C. AU - Buijs, R.M.* AU - Woods, S.C.* AU - Kalsbeek, A.* AU - Seeley, R.J.* AU - Nawroth, P.P.* AU - Bidlingmaier, M.* AU - Tschöp, M.H. AU - Yi, C.X.* C1 - 51484 C2 - 43151 CY - Amsterdam SP - 897-908 TI - Dietary sugars, not lipids, drive hypothalamic inflammation. JO - Mol. Metab. VL - 6 IS - 8 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Objective: Leptin is a cytokine produced by adipose tissue that acts mainly on the hypothalamus to regulate appetite and energy homeostasis. Previous studies revealed that the leptin receptor is expressed not only in neurons, but also in glial cells. Microglia are resident immune cells in the brain that play an essential role in immune defense and neural network development. Previously we reported that microglial morphology and cytokine production are changed in the leptin receptor deficient db/db mouse, suggesting that leptin's central effects on metabolic control might involve signaling through microglia. In the current study, we aimed to uncover the role of leptin signaling in microglia in systemic metabolic control. Methods: We generated a mouse model with leptin receptor deficiency, specifically in the myeloid cells, to determine the role of microglial leptin signaling in the development of metabolic disease and to investigate microglial functions. Results: We discovered that these mice have increased body weight with hyperphagia. In the hypothalamus, pro-opiomelanocortin neuron numbers in the arcuate nucleus (ARC) and alpha-MSH projections from the ARC to the paraventricular nucleus (PVN) decreased, which was accompanied by the presence of less ramified microglia with impaired phagocytic capacity in the PVN. Conclusions: Myeloid cell leptin receptor deficient mice partially replicate the db/db phenotype. Leptin signaling in hypothalamic microglia is important for microglial function and a correct formation of the hypothalamic neuronal circuit regulating metabolism. (C) 2017 The Authors. Published by Elsevier GmbH. AU - Gao, Y.* AU - Vidal-Itriago, A.* AU - Milanova, I.* AU - Korpel, N.L.* AU - Kalsbeek, M.J.* AU - Tom, R.Z. AU - Kalsbeek, A.* AU - Hofmann, S.M. AU - Yi, C.X.* C1 - 52415 C2 - 43953 CY - Amsterdam SP - 155-160 TI - Deficiency of leptin receptor in myeloid cells disrupts hypothalamic metabolic circuits and causes body weight increase. JO - Mol. Metab. VL - 7 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Objective Angiopoietin-like protein-4 (ANGPTL4) is a circulating protein that is highly expressed in liver and implicated in regulation of plasma triglyceride levels. Systemic ANGPTL4 increases during prolonged fasting and is suggested to be secreted from skeletal muscle following exercise. Methods We investigated the origin of exercise-induced ANGPTL4 in humans by measuring the arterial-to-venous difference over the leg and the hepato-splanchnic bed during an acute bout of exercise. Furthermore, the impact of the glucagon-to-insulin ratio on plasma ANGPTL4 was studied in healthy individuals. The regulation of ANGPTL4 was investigated in both hepatic and muscle cells. Results The hepato-splanchnic bed, but not the leg, contributed to exercise-induced plasma ANGPTL4. Further studies using hormone infusions revealed that the glucagon-to-insulin ratio is an important regulator of plasma ANGPTL4 as elevated glucagon in the absence of elevated insulin increased plasma ANGPTL4 in resting subjects, whereas infusion of somatostatin during exercise blunted the increase of both glucagon and ANGPTL4. Moreover, activation of the cAMP/PKA signaling cascade let to an increase in ANGPTL4 mRNA levels in hepatic cells, which was prevented by inhibition of PKA. In humans, muscle ANGPTL4 mRNA increased during fasting, with only a marginal further induction by exercise. In human muscle cells, no inhibitory effect of AMPK activation could be demonstrated on ANGPTL4 expression. Conclusions The data suggest that exercise-induced ANGPTL4 is secreted from the liver and driven by a glucagon-cAMP-PKA pathway in humans. These findings link the liver, insulin/glucagon, and lipid metabolism together, which could implicate a role of ANGPTL4 in metabolic diseases.   AU - Ingerslev, B.* AU - Hansen, J.S.* AU - Hoffmann, C.M.* AU - Clemmesen, J.O.* AU - Secher, N.H.* AU - Scheler, M. AU - Hrabě de Angelis, M. AU - Häring, H.-U. AU - Pedersen, B.K.* AU - Weigert, C. AU - Plomgaard, P.* C1 - 51502 C2 - 43182 CY - Amsterdam SP - 1286-1295 TI - Angiopoietin-like protein 4 is an exercise-induced hepatokine in humans, regulated by glucagon and cAMP. JO - Mol. Metab. VL - 6 IS - 10 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Objective: Obesity is a major health threat that affects men and women equally. Despite this fact, weight-loss potential of pharmacotherapies is typically first evaluated in male mouse models of diet-induced obesity (DIO). To address this disparity we herein determined whether a monomeric peptide with agonism at the receptors for glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon is equally efficient in correcting DIO, dyslipidemia, and glucose metabolism in DIO female mice as it has been previously established for DIO male mice. Methods: Female C57BL/6J mice and a cohort of fatmass-matched C57BL/6J male mice were treated for 27 days via subcutaneous injections with either the GLP-1/GIP/glucagon triagonist or PBS. A second cohort of C57BL/6J male mice was included to match the females in the duration of the high-fat, high-sugar diet (HFD) exposure. Results: Our results show that GLP-1/GIP/glucagon triple agonism inhibits food intake and decreases body weight and body fat mass with comparable potency in male and female mice that have been matched for body fat mass. Treatment improved dyslipidemia in both sexes and reversed diet-induced steatohepatitis to a larger extent in female mice compared to male mice. Conclusions: We herein show that a recently developed unimolecular peptide triagonist is equally efficient in both sexes, suggesting that this polypharmaceutical strategy might be a relevant alternative to bariatric surgery for the treatment of obesity and related metabolic disorders. AU - Jall, S. AU - Sachs, S. AU - Clemmensen, C. AU - Finan, B. AU - Neff, F. AU - DiMarchi, R.D.* AU - Tschöp, M.H. AU - Müller, T.D. AU - Hofmann, S.M. C1 - 50748 C2 - 42635 CY - Amsterdam SP - 440-446 TI - Monomeric GLP-1/GIP/glucagon triagonism corrects obesity, hepatosteatosis, and dyslipidemia in female mice. JO - Mol. Metab. VL - 6 IS - 5 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Objective Obesity-associated WAT inflammation is characterized by the accumulation and local activation of macrophages (MΦs), and recent data from mouse studies suggest that macrophages are modifiers of adipocyte energy metabolism and mitochondrial function. As mitochondrial dysfunction has been associated with obesity and the metabolic syndrome in humans, herein we aimed to delineate how human macrophages may affect energy metabolism of white adipocytes. Methods Human adipose tissue gene expression analysis for markers of macrophage activation and tissue inflammation (CD11c, CD40, CD163, CD206, CD80, MCP1, TNFα) in relationship to mitochondrial complex I (NDUFB8) and complex III (UQCRC2) was performed on subcutaneous WAT of 24 women (BMI 20–61 kg/m2). Guided by these results, the impact of secreted factors of LPS/IFNγ- and IL10/TGFβ-activated human macrophages (THP1, primary blood-derived) on mitochondrial function in human subcutaneous white adipocytes (SGBS, primary) was determined by extracellular flux analysis (Seahorse technology) and gene/protein expression. Results Stepwise regression analysis of human WAT gene expression data revealed that a linear combination of CD40 and CD163 was the strongest predictor for mitochondrial complex I (NDUFB8) and complex III (UQCRC2) levels, independent of BMI. IL10/TGFβ-activated MΦs displayed high CD163 and low CD40 expression and secreted factors that decreased UQCRC2 gene/protein expression and ATP-linked respiration in human white adipocytes. In contrast, LPS/IFNγ-activated MΦs showed high CD40 and low CD163 expression and secreted factors that enhanced adipocyte mitochondrial activity resulting in a total difference of 37% in ATP-linked respiration of white adipocytes (p = 0.0024) when comparing the effect of LPS/IFNγ- vs IL10/TGFβ-activated MΦs. Conclusion Our data demonstrate that macrophages modulate human adipocyte energy metabolism via an activation-dependent paracrine mechanism.   AU - Keuper, M. AU - Sachs, S. AU - Walheim, E. AU - Berti, L. AU - Raedle, B. AU - Tews, D.* AU - Fischer-Posovszky, P.* AU - Wabitsch, M.* AU - Hrabě de Angelis, M. AU - Kastenmüller, G. AU - Tschöp, M.H. AU - Jastroch, M. AU - Staiger, H. AU - Hofmann, S.M. C1 - 51586 C2 - 43249 CY - Amsterdam SP - 1226-1239 TI - Activated macrophages control human adipocyte mitochondrial bioenergetics via secreted factors. JO - Mol. Metab. VL - 6 IS - 10 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Objectives Human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) can generate any given cell type in the human body. One challenge for cell-replacement therapy is the efficient differentiation and expansion of large quantities of progenitor cells from pluripotent stem cells produced under good manufacturing practice (GMP). FOXA2 and SOX17 double positive definitive endoderm (DE) progenitor cells can give rise to all endoderm-derived cell types in the thymus, thyroid, lung, pancreas, liver, and gastrointestinal tract. FOXA2 is a pioneer transcription factor in DE differentiation that is also expressed and functionally required during pancreas development and islet cell homeostasis. Current differentiation protocols can successfully generate endoderm; however, generation of mature glucose-sensitive and insulin-secreting β-cells is still a challenge. As a result, it is of utmost importance to screen for small molecules that can improve DE and islet cell differentiation for cell-replacement therapy for diabetic patients. Methods The aim of this study was to identify and validate small molecules that can induce DE differentiation and further enhance pancreatic progenitor differentiation. Therefore, we developed a large scale, high-content screen for testing a chemical library of 23,406 small molecules to identify compounds that induce FoxA2 in mouse embryonic stem cells (mESCs). Results Based on our high-content screen algorithm, we selected 84 compounds that directed differentiation of mESCs towards the FoxA2 lineage. Strikingly, we identified ROCK inhibition (ROCKi) as a novel mechanism of endoderm induction in mESCs and hESCs. DE induced by the ROCK inhibitor Fasudil efficiently gives rise to PDX1+ pancreatic progenitors from hESCs. Conclusion Taken together, DE induction by ROCKi can simplify and improve current endoderm and pancreatic differentiation protocols towards a GMP-grade cell product for β-cell replacement. AU - Korostylev, A. AU - Mahaddalkar, P.U. AU - Keminer, O.* AU - Hadian, K. AU - Schorpp, K.K. AU - Lickert, H. C1 - 51160 C2 - 42668 CY - Amsterdam SP - 640-650 TI - A high-content small molecule screen identifies novel inducers of definitive endoderm. JO - Mol. Metab. VL - 6 IS - 7 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AU - Lickert, H. AU - Kaestner, K.H.* C1 - 52711 C2 - 44212 CY - Amsterdam SP - VI-VI TI - Islet biology. JO - Mol. Metab. VL - 6 IS - 9 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Objective: While prostate cancer does not occur more often in men with diabetes, survival is markedly reduced in this patient group. Androgen signaling is a known and major driver for prostate cancer progression. Therefore, we analyzed major components of the androgen signaling chain and cell proliferation in relation to type 2 diabetes. Methods: Tumor content of 70 prostate tissue samples of men with type 2 diabetes and 59 samples of patients without diabetes was quantified by an experienced pathologist, and a subset of 51 samples was immunohistochemically stained for androgen receptor (AR). mRNA expression of AR, insulin receptor isoform A (IR-A) and B (IR-B) IGF-1 receptor (IGF1R), Cyp27A1 and Cyp7B1, PSA gene KLK3, PSMA gene FOLH1, Ki-67 gene MKI67, and estrogen receptor beta (ESR2) were analyzed by RT-qPCR. Results: AR mRNA and protein expression were associated with the tumor content only in men with diabetes. AR expression also correlated with downstream targets PSA (KLK3) and PSMA (FOLH1) and increased cell proliferation. Only in diabetes, AR expression was correlated to higher IR-AIIR-B ratio and lower IR-B/IGF1R ratio, thus, in favor of the mitogenic isoforms. Reduced Cyp27A1 and increased Cyp7B1 expressions in tumor suggest lower levels of protective estrogen receptor ligands in diabetes. Conclusions: We report elevated androgen receptor signaling and activity presumably due to altered insulin/IGF-1 receptors and decreased levels of protective estrogen receptor ligands in prostate cancer in men with diabetes. Our results reveal new insights why these patients have a worse prognosis. These findings provide the basis for future clinical trials to investigate treatment response in patients with prostate cancer and diabetes. 2017 The Authors. Published by Elsevier GmbH. AU - Lutz, S.Z. AU - Hennenlotter, J.* AU - Scharpf, M.O.* AU - Sailer, C. AU - Fritsche, L. AU - Schmid, V.* AU - Kantartzis, K. AU - Wagner, R. AU - Lehmann, R. AU - Berti, L. AU - Peter, A. AU - Staiger, H. AU - Fritsche, A. AU - Fend, A.* AU - Todenhöfer, T.* AU - Stenzl, A.* AU - Häring, H.-U. AU - Heni, M. C1 - 52482 C2 - 44004 CY - Amsterdam SP - 158-166 TI - Androgen receptor overexpression in prostate cancer in type 2 diabetes. JO - Mol. Metab. VL - 8 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Objective: Dietary protein dilution (PD) has been associated with metabolic advantages such as improved glucose homeostasis and increased energy expenditure. This phenotype involves liver-induced release of FGF21 in response to amino acid insufficiency; however, it has remained unclear whether dietary dilution of specific amino acids (AAs) is also required. Circulating branched chain amino acids (BCAAs) are sensitive to protein intake, elevated in the serum of obese humans and mice and thought to promote insulin resistance. We tested whether replenishment of dietary BCAAs to an AA-diluted (AAD) diet is sufficient to reverse the glucoregulatory benefits of dietary PD. Methods: We conducted AA profiling of serum from healthy humans and lean and high fat-fed or New Zealand obese (NZO) mice following dietary PD. We fed wildtype and NZO mice one of three amino acid defined diets: control, total AAD, or the same diet with complete levels of BCAAs (AAD + BCAA). We quantified serum AAs and characterized mice in terms of metabolic efficiency, body composition, glucose homeostasis, serum FGF21, and tissue markers of the integrated stress response (ISR) and mTORC1 signaling. Results: Serum BCAAs, while elevated in serum from hyperphagic NZO, were consistently reduced by dietary PD in humans and murine models. Repletion of dietary BCAAs modestly attenuated insulin sensitivity and metabolic efficiency in wildtype mice but did not restore hyperglycemia in NZO mice. While hepatic markers of the ISR such as P-eIF2α and FGF21 were unabated by dietary BCAA repletion, hepatic and peripheral mTORC1 signaling were fully or partially restored, independent of changes in circulating glucose or insulin. Conclusions: Repletion of BCAAs in dietary PD is sufficient to oppose changes in somatic mTORC1 signaling but does not reverse the hepatic ISR nor induce insulin resistance in type 2 diabetes during dietary PD. AU - Maida, A. AU - Chan, J.S.K. AU - Sjøberg, K.A.* AU - Zota, A. AU - Schmoll, D.* AU - Kiens, B.* AU - Herzig, S. AU - Rose, A.J.* C1 - 51576 C2 - 43306 CY - Amsterdam SP - 873-881 TI - Repletion of branched chain amino acids reverses mTORC1 signaling but not improved metabolism during dietary protein dilution. JO - Mol. Metab. VL - 6 IS - 8 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Objective The fatty acid receptor 1 (FFAR1/GPR40) mediates fatty acid-dependent augmentation of glucose-induced insulin secretion (GIIS) in pancreatic β-cells. Genetically engineered Ffar1-knockout/congenic mice univocally displayed impaired fatty acid-mediated insulin secretion, but in vivo experiments delivered controversial results regarding the function of FFAR1 in glucose homeostasis and liver steatosis. This study presents a new coisogenic mouse model carrying a point mutation in Ffar1 with functional consequence. These mice reflect the situations in humans in which point mutations can lead to protein malfunction and disease development. Methods The Munich N-ethyl-N-nitrosourea (ENU) mutagenesis-derived F1 archive containing over 16,800 sperms and corresponding DNA samples was screened for mutations in the coding region of Ffar1. Two missense mutations (R258W and T146S) in the extracellular domain of the protein were chosen and homozygote mice were generated. The functional consequence of these mutations was examined in vitro in isolated islets and in vivo in chow diet and high fat diet fed mice. Results Palmitate, 50 μM, and the FFAR1 agonist TUG-469, 3 μM, stimulated insulin secretion in islets of Ffar1T146S/T146S mutant mice and of wild-type littermates, while in islets of Ffar1R258W/R258W mutant mice, these stimulatory effects were abolished. Insulin content and mRNA levels of Ffar1, Glp1r, Ins2, Slc2a2, Ppara, and Ppard were not significantly different between wild type and Ffar1R258W/R258W mouse islets. Palmitate exposure, 600 μM, significantly increased Ppara mRNA levels in wild type but not in Ffar1R258W/R258W mouse islets. On the contrary, Slc2a2 mRNA levels were significantly reduced in both wild type and Ffar1R258W/R258W mouse islets after palmitate treatment. HFD feeding induced glucose intolerance in wild-type mice. Ffar1R258W/R258W mutant mice remained glucose tolerant although their body weight gain, liver steatosis, insulin resistance, and plasma insulin levels were not different from those of wild-type littermates. Worth mentioning, fasting plasma insulin levels were lower in Ffar1R258W/R258W mice. Conclusion A point mutation in Ffar1 abrogates the stimulatory effect of palmitate on GIIS, an effect that does not necessarily translate to HFD-induced glucose intolerance. AU - Sabrautzki, S. AU - Kaiser, G. AU - Przemeck, G.K.H. AU - Gerst, F. AU - Lorza-Gil, E. AU - Panse, M.* AU - Sartorius, T.* AU - Hoene, M.* AU - Marschall, S. AU - Häring, H.-U. AU - Hrabě de Angelis, M. AU - Ullrich, S. C1 - 51585 C2 - 43248 CY - Amsterdam SP - 1304-1312 TI - Point mutation of Ffar1 abrogates fatty acid-dependent insulin secretion, but protects against HFD-induced glucose intolerance. JO - Mol. Metab. VL - 6 IS - 10 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Objective Metformin, the first line drug for treatment of type 2 diabetes, suppresses hepatic gluconeogenesis and reduces body weight in patients, the latter by an unknown mechanism. Methods Mice on a high fat diet were continuously fed metformin in a therapeutically relevant dose, mimicking a retarded formulation. Results Feeding metformin in pharmacologically relevant doses to mice on a high fat diet normalized HbA1c levels and ameliorated glucose tolerance, as expected, but also considerably slowed down weight gain. This was due to increased energy expenditure, since food intake was unchanged and locomotor activity was even decreased. Metformin caused lactate accumulation in the intestinal wall and in portal venous blood but not in peripheral blood or the liver. Increased conversion of glucose-1-13C to glucose-1,6-13C under metformin strongly supports a futile cycle of lactic acid production in the intestinal wall, and usage of the produced lactate for gluconeogenesis in liver. Conclusions The reported glucose–lactate–glucose cycle is a highly energy consuming process, explaining the beneficial effects of metformin given continuously on the development of a type 2 diabetic-like state in our mice. AU - Schommers, P.* AU - Thurau, A.* AU - Bultmann-Mellin, I.* AU - Guschlbauer, M.* AU - Klatt, A.R.* AU - Rozman, J. AU - Klingenspor, M. AU - Hrabě de Angelis, M. AU - Alber, J.* AU - Gründemann, D.* AU - Sterner-Kock, A.* AU - Wiesner, R.J.* C1 - 51087 C2 - 42771 CY - Amsterdam SP - 737-747 TI - Metformin causes a futile intestinal-hepatic cycle which increase energy expenditure and slows down development of a type 2 diabetes-like state. JO - Mol. Metab. VL - 6 IS - 7 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AU - Teperino, R. C1 - 51633 C2 - 43403 CY - Amsterdam SP - 1079-1080 TI - Anti-hypertensive treatment in pregnancy impacts offspring growth and metabolism: Q&A. JO - Mol. Metab. VL - 6 IS - 10 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - Background: Diabetes mellitus is characterized by loss or dysfunction of insulin-producing β-cells in the pancreas, resulting in failure of blood glucose regulation and devastating secondary complications. Thus, β-cells are currently the prime target for cell-replacement and regenerative therapy. Triggering endogenous repair is a promising strategy to restore β-cell mass and normoglycemia in diabetic patients. Potential strategies include targeting specific β-cell subpopulations to increase proliferation or maturation. Alternatively, transdifferentiation of pancreatic islet cells (e.g. α- or δ-cells), extra-islet cells (acinar and ductal cells), hepatocytes, or intestinal cells into insulin-producing cells might improve glycemic control. To this end, it is crucial to systematically characterize and unravel the transcriptional program of all pancreatic cell types at the molecular level in homeostasis and disease. Furthermore, it is necessary to better determine the underlying mechanisms of β-cell maturation, maintenance, and dysfunction in diabetes, to identify and molecularly profile endocrine subpopulations with regenerative potential, and to translate the findings from mice to man. Recent approaches in single-cell biology started to illuminate heterogeneity and plasticity in the pancreas that might be targeted for β-cell regeneration in diabetic patients. Scope of review: This review discusses recent literature on single-cell analysis including single-cell RNA sequencing, single-cell mass cytometry, and flow cytometry of pancreatic cell types in the context of mechanisms of endogenous β-cell regeneration. We discuss new findings on the regulation of postnatal β-cell proliferation and maturation. We highlight how single-cell analysis recapitulates described principles of functional β-cell heterogeneity in animal models and adds new knowledge on the extent of β-cell heterogeneity in humans as well as its role in homeostasis and disease. Furthermore, we summarize the findings on cell subpopulations with regenerative potential that might enable the formation of new β-cells in diseased state. Finally, we review new data on the transcriptional program and function of rare pancreatic cell types and their implication in diabetes. Major conclusion: Novel, single-cell technologies offer high molecular resolution of cellular heterogeneity within the pancreas and provide information on processes and factors that govern β-cell homeostasis, proliferation, and maturation. Eventually, these technologies might lead to the characterization of cells with regenerative potential and unravel disease-associated changes in gene expression to identify cellular and molecular targets for therapy. AU - Tritschler, S. AU - Theis, F.J. AU - Lickert, H. AU - Böttcher, A. C1 - 51671 C2 - 43394 CY - Amsterdam SP - 974-990 TI - Systematic single-cell analysis provides new insights into heterogeneity and plasticity of the pancreas. JO - Mol. Metab. VL - 6 IS - 9 PB - Elsevier Science Bv PY - 2017 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Central melanocortin pathways are well-established regulators of energy balance. However, scant data exist about the role of systemic melanocortin peptides. We set out to determine if peripheral α-melanocyte stimulating hormone (α-MSH) plays a role in glucose homeostasis and tested the hypothesis that the pituitary is able to sense a physiological increase in circulating glucose and responds by secreting α-MSH. METHODS: We established glucose-stimulated α-MSH secretion using humans, non-human primates, and mouse models. Continuous α-MSH infusions were performed during glucose tolerance tests and hyperinsulinemic-euglycemic clamps to evaluate the systemic effect of α-MSH in glucose regulation. Complementary ex vivo and in vitro techniques were employed to delineate the direct action of α-MSH via the melanocortin 5 receptor (MC5R)-PKA axis in skeletal muscles. Combined treatment of non-selective/selective phosphodiesterase inhibitor and α-MSH was adopted to restore glucose tolerance in obese mice. RESULTS: Here we demonstrate that pituitary secretion of α-MSH is increased by glucose. Peripheral α-MSH increases temperature in skeletal muscles, acts directly on soleus and gastrocnemius muscles to significantly increase glucose uptake, and enhances whole-body glucose clearance via the activation of muscle MC5R and protein kinase A. These actions are absent in obese mice, accompanied by a blunting of α-MSH-induced cAMP levels in skeletal muscles of obese mice. Both selective and non-selective phosphodiesterase inhibition restores α-MSH induced skeletal muscle glucose uptake and improves glucose disposal in obese mice. CONCLUSION: These data describe a novel endocrine circuit that modulates glucose homeostasis by pituitary α-MSH, which increases muscle glucose uptake and thermogenesis through the activation of a MC5R-PKA-pathway, which is disrupted in obesity. AU - Enriori, P.J.* AU - Chen, W.* AU - Garcia-Rudaz, M.C.* AU - Grayson, B.E.* AU - Evans, A.E.* AU - Comstock, S.M.* AU - Gebhardt, U.* AU - Müller, H.L.* AU - Reinehr, T.* AU - Henry, B.A.* AU - Brown, R.D. Jr.* AU - Bruce, C.R.* AU - Simonds, S.E.* AU - Litwak, S.A.* AU - McGee, S.L.* AU - Luquet, S.* AU - Martinez, S.* AU - Jastroch, M. AU - Tschöp, M.H. AU - Watt, M.J.* AU - Clarke, I.J.* AU - Roth, C.L.* AU - Grove, K.L.* AU - Cowley, M.A.* C1 - 49582 C2 - 40841 CY - Amsterdam SP - 807-822 TI - α-Melanocyte stimulating hormone promotes muscle glucose uptake via melanocortin 5 receptors. JO - Mol. Metab. VL - 5 IS - 10 PB - Elsevier Science Bv PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: In rodents and humans, besides brown adipose tissue (BAT), islands of thermogenic adipocytes, termed "brite" (brown-in-white) or beige adipocytes, emerge within white adipose tissue (WAT) after cold exposure or β3-adrenoceptor stimulation, which may protect from obesity and associated diseases. microRNAs are novel modulators of adipose tissue development and function. The purpose of this work was to characterize the role of microRNAs in the control of brite adipocyte formation. METHODS/RESULTS: Using human multipotent adipose derived stem cells, we identified miR-125b-5p as downregulated upon brite adipocyte formation. In humans and rodents, miR-125b-5p expression was lower in BAT than in WAT. In vitro, overexpression and knockdown of miR-125b-5p decreased and increased mitochondrial biogenesis, respectively. In vivo, miR-125b-5p levels were downregulated in subcutaneous WAT and interscapular BAT upon β3-adrenergic receptor stimulation. Injections of an miR-125b-5p mimic and LNA inhibitor directly into WAT inhibited and increased β3-adrenoceptor-mediated induction of UCP1, respectively, and mitochondrial brite adipocyte marker expression and mitochondriogenesis. CONCLUSION: Collectively, our results demonstrate that miR-125b-5p plays an important role in the repression of brite adipocyte function by modulating oxygen consumption and mitochondrial gene expression. AU - Giroud, M.* AU - Pisani, D.F.* AU - Karbiener, M.* AU - Barquissau, V.* AU - Ghandour, R.A.* AU - Tews, D.* AU - Fischer-Posovszky, P.* AU - Chambard, J.C.* AU - Knippschild, U.* AU - Niemi, T.* AU - Taittonen, M.* AU - Nuutila, P.* AU - Wabitsch, M.* AU - Herzig, S. AU - Virtanen, K.A.* AU - Langin, D.* AU - Scheideler, M. AU - Amri, E.Z.* C1 - 49539 C2 - 40768 CY - Amsterdam SP - 615-25 TI - miR-125b affects mitochondrial biogenesis and impairs brite adipocyte formation and function. JO - Mol. Metab. VL - 5 IS - 8 PB - Elsevier Science Bv PY - 2016 SN - 2212-8778 ER - TY - JOUR AU - Hausmann, S. AU - Ussar, S. C1 - 48395 C2 - 41019 CY - Amsterdam SP - 253-254 TI - Insulin receptor trafficking steers insulin action. JO - Mol. Metab. VL - 5 IS - 4 PB - Elsevier Science Bv PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - Background: High density lipoproteins (HDLs) are thought to be atheroprotective and to reduce the risk of cardiovascular disease (CVD). Besides their antioxidant, antithrombotic, anti-inflammatory, anti-apoptotic properties in the vasculature, HDLs also improve glucose metabolism in skeletal muscle. Scope of the review: Herein, we review the functional role of HDLs to improve metabolic disorders, especially those involving insulin resistance and to induce regression of CVD with a particular focus on current pharmacological treatment options as well as lifestyle interventions, particularly exercise. Major conclusions: Functional properties of HDLs continue to be considered important mediators to reverse metabolic dysfunction and to regress atherosclerotic cardiovascular disease. Lifestyle changes are often recommended to reduce the risk of CVD, with exercise being one of the most important of these. Understanding how exercise improves HDL function will likely lead to new approaches to battle the expanding burden of obesity and the metabolic syndrome. AU - Klancic, T. AU - Woodward, L.* AU - Hofmann, S.M. AU - Fisher, E.A.* C1 - 48433 C2 - 41158 CY - Amsterdam SP - 321-327 TI - High density lipoprotein and metabolic disease: Potential benefits of restoring its functional properties. JO - Mol. Metab. VL - 5 IS - 5 PB - Elsevier Science Bv PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - Objective: We have recently shown that acute inhibition of both mTOR complexes (mTORC1 and mTORC2) increases whole-body lipid utilization, while mTORC1 inhibition had no effect. Therefore, we tested the hypothesis that mTORC2 regulates lipid metabolism in skeletal muscle. Methods: Body composition, substrate utilization and muscle lipid storage were measured in mice lacking mTORC2 activity in skeletal muscle (specific knockout of RICTOR (Ric mKO)). We further examined the RICTOR/mTORC2-controlled muscle metabolome and proteome; and performed follow-up studies in other genetic mouse models and in cell culture. Results: Ric mKO mice exhibited a greater reliance on fat as an energy substrate, a re-partitioning of lean to fat mass and an increase in intramyocellular triglyceride (IMTG) content, along with increases in several lipid metabolites in muscle. Unbiased proteomics revealed an increase in the expression of the lipid droplet binding protein Perilipin 3 (PLIN3) in muscle from Ric mKO mice. This was associated with increased AMPK activity in Ric mKO muscle. Reducing AMPK kinase activity decreased muscle PLIN3 expression and IMTG content. AMPK agonism, in turn, increased PLIN3 expression in a FoxO1 dependent manner. PLIN3 overexpression was sufficient to increase triglyceride content in muscle cells. Conclusions: We identified a novel link between mTORC2 and PLIN3, which regulates lipid storage in muscle. While mTORC2 is a negative regulator, we further identified AMPK as a positive regulator of PLIN3, which impacts whole-body substrate utilization and nutrient partitioning. AU - Kleinert, M. AU - Parker, B.L.* AU - Chaudhuri, R.* AU - Fazakerley, D.J.* AU - Serup, A.* AU - Thomas, K.C.* AU - Krycer, J.R.* AU - Sylow, L.* AU - Fritzen, A.M.* AU - Hoffman, N.J.* AU - Jeppesen, J.* AU - Schjerling, P.* AU - Ruegg, M.A.* AU - Kiens, B.* AU - James, D.E.* AU - Richter, E.A.* C1 - 49220 C2 - 34076 CY - Amsterdam SP - 646-655 TI - MTORC2 and AMPK differentially regulate muscle triglyceride content via perilipin 3. JO - Mol. Metab. VL - 5 IS - 8 PB - Elsevier Science Bv PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - Objective Gut microbiota may promote positive energy balance; however, germfree mice can be either resistant or susceptible to diet-induced obesity (DIO) depending on the type of dietary intervention. We here sought to identify the dietary constituents that determine the susceptibility to body fat accretion in germfree (GF) mice. Methods GF and specific pathogen free (SPF) male C57BL/6N mice were fed high-fat diets either based on lard or palm oil for 4 wks. Mice were metabolically characterized at the end of the feeding trial. FT-ICR-MS and UPLC-TOF-MS were used for cecal as well as hepatic metabolite profiling and cecal bile acids quantification, respectively. Hepatic gene expression was examined by qRT-PCR and cecal gut microbiota of SPF mice was analyzed by high-throughput 16S rRNA gene sequencing. Results GF mice, but not SPF mice, were completely DIO resistant when fed a cholesterol-rich lard-based high-fat diet, whereas on a cholesterol-free palm oil-based high-fat diet, DIO was independent of gut microbiota. In GF lard-fed mice, DIO resistance was conveyed by increased energy expenditure, preferential carbohydrate oxidation, and increased fecal fat and energy excretion. Cecal metabolite profiling revealed a shift in bile acid and steroid metabolites in these lean mice, with a significant rise in 17β-estradiol, which is known to stimulate energy expenditure and interfere with bile acid metabolism. Decreased cecal bile acid levels were associated with decreased hepatic expression of genes involved in bile acid synthesis. These metabolic adaptations were largely attenuated in GF mice fed the palm-oil based high-fat diet. We propose that an interaction of gut microbiota and cholesterol metabolism is essential for fat accretion in normal SPF mice fed cholesterol-rich lard as the main dietary fat source. This is supported by a positive correlation between bile acid levels and specific bacteria of the order Clostridiales (phylum Firmicutes) as a characteristic feature of normal SPF mice fed lard. Conclusions In conclusion, our study identified dietary cholesterol as a candidate ingredient affecting the crosstalk between gut microbiota and host metabolism. AU - Kübeck, R.* AU - Bonet-Ripoll, C.* AU - Hoffmann, C.M.* AU - Walker, A. AU - Müller, V.M.* AU - Schüppel, V.L.* AU - Lagkouvardos, I.* AU - Scholz, B.A.* AU - Engel, K.H.* AU - Daniel, H.* AU - Schmitt-Kopplin, P. AU - Haller, D.* AU - Clavel, T.* AU - Klingenspor, M.* C1 - 50057 C2 - 42109 CY - Amsterdam SP - 1162-1174 TI - Dietary fat and gut microbiota interactions determine diet-induced obesity in mice. JO - Mol. Metab. VL - 5 IS - 12 PB - Elsevier Science Bv PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Insulin release from pancreatic islet β cells should be tightly controlled to avoid hypoglycemia and insulin resistance. The cortical actin cytoskeleton is a gate for regulated exocytosis of insulin secretory granules (SGs) by restricting their mobility and access to the plasma membrane. Prior studies suggest that SGs interact with F-actin through their transmembrane cargo islet cell autoantigen 512 (Ica512) (also known as islet antigen 2/Ptprn). Here we investigated how Ica512 modulates SG trafficking and exocytosis. METHODS: Transcriptomic changes in Ica512 (-/-) mouse islets were analyzed. Imaging as well as biophysical and biochemical methods were used to validate if and how the Ica512-regulated gene villin modulates insulin secretion in mouse islets and insulinoma cells. RESULTS: The F-actin modifier villin was consistently downregulated in Ica512 (-/-) mouse islets and in Ica512-depleted insulinoma cells. Villin was enriched at the cell cortex of β cells and dispersed villin (-/-) islet cells were less round and less deformable. Basal mobility of SGs in villin-depleted cells was enhanced. Moreover, in cells depleted either of villin or Ica512 F-actin cages restraining cortical SGs were enlarged, basal secretion was increased while glucose-stimulated insulin release was blunted. The latter changes were reverted by overexpressing villin in Ica512-depleted cells, but not vice versa. CONCLUSION: Our findings show that villin controls the size of the F-actin cages restricting SGs and, thus, regulates their dynamics and availability for exocytosis. Evidence that villin acts downstream of Ica512 also indicates that SGs directly influence the remodeling properties of the cortical actin cytoskeleton for tight control of insulin secretion. AU - Mziaut, H. AU - Mulligan, B. AU - Hoboth, P. AU - Otto, O.* AU - Ivanova, A. AU - Herbig, M.* AU - Schumann, D.* AU - Hildebrandt, T.B.* AU - Dehghany, J.* AU - Sönmez, A. AU - Münster, C. AU - Meyer-Hermann, M.* AU - Guck, J.* AU - Kalaidzidis, Y.* AU - Solimena, M. C1 - 49538 C2 - 40782 CY - Amsterdam SP - 656-68 TI - The F-actin modifier villin regulates insulin granule dynamics and exocytosis downstream of islet cell autoantigen 512. JO - Mol. Metab. VL - 5 IS - 8 PB - Elsevier Science Bv PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Circulating long-chain free fatty acids (FFAs) are important metabolic signals that acutely enhance fatty acid oxidation, thermogenesis, energy expenditure, and insulin secretion. However, if chronically elevated, they provoke inflammation, insulin resistance, and β-cell failure. Moreover, FFAs act via multiple signaling pathways as very potent regulators of gene expression. In human skeletal muscle cells differentiated in vitro (myotubes), we have shown in previous studies that the expression of CSF3, the gene encoding granulocyte colony-stimulating factor (G-CSF), is markedly induced upon FFA treatment and exercise. METHODS AND RESULTS: We now report that CSF3 is induced in human myotubes by saturated, but not unsaturated, FFAs via Toll-like receptor 4-dependent and -independent pathways including activation of Rel-A, AP-1, C/EBPα, Src, and stress kinases. Furthermore, we show that human adipocytes and myotubes treated with G-CSF become insulin-resistant. In line with this, a functional polymorphism in the CSF3 gene affects adipose tissue- and whole-body insulin sensitivity and glucose tolerance in human subjects with elevated plasma FFA concentrations. CONCLUSION: G-CSF emerges as a new player in FFA-induced insulin resistance and thus may be of interest as a target for prevention and treatment of type 2 diabetes. AU - Ordelheide, A.-M. AU - Gommer, N.* AU - Böhm, A. AU - Hermann, C. AU - Thielker, I. AU - Machicao, F. AU - Fritsche, A. AU - Stefan, N. AU - Häring, H.-U. AU - Staiger, H. C1 - 48394 C2 - 41020 CY - Amsterdam SP - 305-316 TI - Granulocyte Colony-Stimulating Factor (G-CSF): A saturated fatty acid-induced myokine with insulin-desensitizing properties in humans. JO - Mol. Metab. VL - 5 IS - 4 PB - Elsevier Science Bv PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - Objective: Fibroblast growth factor 21 (FGF21) was recently discovered as stress-induced myokine during mitochondrial disease and proposed as key metabolic mediator of the integrated stress response (ISR) presumably causing systemic metabolic improvements. Curiously, the precise cell-non-autonomous and cell-autonomous relevance of endogenous FGF21 action remained poorly understood. Methods: We made use of the established UCP1 transgenic (TG) mouse, a model of metabolic perturbations made by a specific decrease in muscle mitochondrial efficiency through increased respiratory uncoupling and robust metabolic adaptation and muscle ISR-driven FGF21 induction. In a cross of TG with Fgf21-knockout (FGF21-/-) mice, we determined the functional role of FGF21 as a muscle stress-induced myokine under low and high fat feeding conditions. Results: Here we uncovered that FGF21 signaling is dispensable for metabolic improvements evoked by compromised mitochondrial function in skeletal muscle. Strikingly, genetic ablation of FGF21 fully counteracted the cell-non-autonomous metabolic remodeling and browning of subcutaneous white adipose tissue (WAT), together with the reduction of circulating triglycerides and cholesterol. Brown adipose tissue activity was similar in all groups. Remarkably, we found that FGF21 played a negligible role in muscle mitochondrial stress-related improved obesity resistance, glycemic control and hepatic lipid homeostasis. Furthermore, the protective cell-autonomous muscle mitohormesis and metabolic stress adaptation, including an increased muscle proteostasis via mitochondrial unfolded protein response (UPRmt) and amino acid biosynthetic pathways did not require the presence of FGF21. Conclusions: Here we demonstrate that although FGF21 drives WAT remodeling, the adaptive pseudo-starvation response under elevated muscle mitochondrial stress conditions operates independently of both WAT browning and FGF21 action. Thus, our findings challenge FGF21 as key metabolic mediator of the mitochondrial stress adaptation and powerful therapeutic target during muscle mitochondrial disease. AU - Ost, M.* AU - Coleman, V.* AU - Voigt, A.* AU - van Schothorst, E.M.* AU - Keipert, S. AU - van der Stelt, I.* AU - Ringel, S.* AU - Graja, A.* AU - Ambrosi, T.* AU - Kipp, A.P.* AU - Jastroch, M. AU - Schulz, T.J.* AU - Keijer, J.* AU - Klaus, S.* C1 - 47549 C2 - 40661 SP - 79-90 TI - Muscle mitochondrial stress adaptation operates independently of endogenous FGF21 action. JO - Mol. Metab. VL - 5 IS - 2 PY - 2016 SN - 2212-8778 ER - TY - JOUR AU - Quarta, C. AU - Clemmensen, C. C1 - 48799 C2 - 41419 CY - Amsterdam SP - 435-436 TI - Unforeseen role for glucocorticoids in combinatorial anti-obesity pharmacology. JO - Mol. Metab. VL - 5 IS - 7 PB - Elsevier Science Bv PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Type 2 diabetes and obesity are emerging pandemics in the 21st century creating worldwide urgency for the development of novel and safe therapies. We investigated trace amine-associated receptor 1 (TAAR1) as a novel target contributing to the control of glucose homeostasis and body weight. METHODS: We investigated the peripheral human tissue distribution of TAAR1 by immunohistochemistry and tested the effect of a small molecule TAAR1 agonist on insulin secretion in vitro using INS1E cells and human islets and on glucose tolerance in C57Bl6, and db/db mice. Body weight effects were investigated in obese DIO mice. RESULTS: TAAR1 activation by a selective small molecule agonist increased glucose-dependent insulin secretion in INS1E cells and human islets and elevated plasma PYY and GLP-1 levels in mice. In diabetic db/db mice, the TAAR1 agonist normalized glucose excursion during an oral glucose tolerance test. Sub-chronic treatment of diet-induced obese (DIO) mice with the TAAR1 agonist resulted in reduced food intake and body weight. Furthermore insulin sensitivity was improved and plasma triglyceride levels and liver triglyceride content were lower than in controls. CONCLUSIONS: We have identified TAAR1 as a novel integrator of metabolic control, which acts on gastrointestinal and pancreatic islet hormone secretion. Thus TAAR1 qualifies as a novel and promising target for the treatment of type 2 diabetes and obesity. AU - Raab, S.* AU - Wang, H.* AU - Uhles, S.* AU - Cole, N.* AU - Alvarez-Sanchez, R.* AU - Künnecke, B.* AU - Ullmer, C.* AU - Matile, H.* AU - Bedoucha, M.* AU - Norcross, R.D.* AU - Ottaway-Parker, N.* AU - Perez-Tilve, D.* AU - Conde Knape, K.* AU - Tschöp, M.H. AU - Hoener, M.C.* AU - Sewing, S.* C1 - 47832 C2 - 39515 SP - 47-56 TI - Incretin-like effects of small molecule trace amine-associated receptor 1 agonists. JO - Mol. Metab. VL - 5 IS - 1 PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Fibroblast activation protein (FAP) is a serine protease belonging to a S9B prolyl oligopeptidase subfamily. This enzyme has been implicated in cancer development and recently reported to regulate degradation of FGF21, a potent metabolic hormone. Using a known FAP inhibitor, talabostat (TB), we explored the impact of FAP inhibition on metabolic regulation in mice. METHODS: To address this question we evaluated the pharmacology of TB in various mouse models including those deficient in FGF21, GLP1 and GIP signaling. We also studied the ability of FAP to process FGF21 in vitro and TB to block FAP enzymatic activity. RESULTS: TB administration to diet-induced obese (DIO) animals led to profound decreases in body weight, reduced food consumption and adiposity, increased energy expenditure, improved glucose tolerance and insulin sensitivity, and lowered cholesterol levels. Total and intact plasma FGF21 were observed to be elevated in TB-treated DIO mice but not lean animals where the metabolic impact of TB was significantly attenuated. Furthermore, and in stark contrast to naïve DIO mice, the administration of TB to obese FGF21 knockout animals demonstrated no appreciable effect on body weight or any other measures of metabolism. In support of these results we observed no enzymatic degradation of human FGF21 at either end of the protein when FAP was inhibited in vitro by TB. CONCLUSIONS: We conclude that pharmacological inhibition of FAP enhances levels of FGF21 in obese mice to provide robust metabolic benefits not observed in lean animals, thus validating this enzyme as a novel drug target for the treatment of obesity and diabetes. AU - Sánchez-Garrido, M.A. AU - Habegger, K.M.* AU - Clemmensen, C. AU - Holleman, C.* AU - Müller, T.D. AU - Perez-Tilve, D.* AU - Li, P.* AU - Agrawal, A.S.* AU - Finan, B. AU - Drucker, D.J.* AU - Tschöp, M.H. AU - DiMarchi, R.D.* AU - Kharitonenkov, A.* C1 - 49581 C2 - 41959 CY - Amsterdam SP - 1015-24 TI - Fibroblast activation protein (FAP) as a novel metabolic target. JO - Mol. Metab. VL - 5 IS - 10 PB - Elsevier Science Bv PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - Objectives Cancer cachexia affects the majority of tumor patients and significantly contributes to high mortality rates in these subjects. Despite its clinical importance, the identity of tumor-borne signals and their impact on specific peripheral organ systems, particularly the heart, remain mostly unknown. Methods and Results By combining differential colon cancer cell secretome profiling with large-scale cardiomyocyte phenotyping, we identified a signature panel of seven “cachexokines”, including Bridging integrator 1, Syntaxin 7, Multiple inositol-polyphosphate phosphatase 1, Glucosidase alpha acid, Chemokine ligand 2, Adamts like 4, and Ataxin-10, which were both sufficient and necessary to trigger cardiac atrophy and aberrant fatty acid metabolism in cardiomyocytes. As a prototypical example, engineered secretion of Ataxin-10 from non-cachexia-inducing cells was sufficient to induce cachexia phenotypes in cardiomyocytes, correlating with elevated Ataxin-10 serum levels in murine and human cancer cachexia models. Conclusions As Ataxin-10 serum levels were also found to be elevated in human cachectic cancer patients, the identification of Ataxin-10 as part of a cachexokine cocktail now provides a rational approach towards personalized predictive, diagnostic and therapeutic measures in cancer cachexia. AU - Schäfer, M. AU - Oeing, C.U.* AU - Rohm, M. AU - Baysal-Temel, E.* AU - Lehmann, L.H.* AU - Bauer, R.* AU - Volz, H.C.* AU - Boutros, M.* AU - Sohn, D.* AU - Sticht, C.* AU - Gretz, N.* AU - Eichelbaum, K.* AU - Werner, T.* AU - Hirt, M.N.* AU - Eschenhagen, T.* AU - Müller-Decker, K.* AU - Strobel, O.* AU - Hackert, T.* AU - Krijgsveld, J.* AU - Katus, H.A.* AU - Berriel Diaz, M. AU - Backs, J.* AU - Herzig, S. C1 - 47446 C2 - 39309 SP - 67-78 TI - Ataxin-10 is part of a cachexokine cocktail triggering cardiac metabolic dysfunction in cancer cachexia. JO - Mol. Metab. VL - 5 IS - 2 PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - Objective Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and is associated with an enhanced risk for liver and cardiovascular diseases and mortality. NAFLD can progress from simple hepatic steatosis to non-alcoholic steatohepatitis (NASH). However, the mechanisms predisposing to this progression remain undefined. Notably, hepatic mitochondrial dysfunction is a common finding in patients with NASH. Due to a lack of appropriate experimental animal models, it has not been evaluated whether this mitochondrial dysfunction plays a causative role for the development of NASH. Methods To determine the effect of a well-defined mitochondrial dysfunction on liver physiology at baseline and during dietary challenge, C57BL/6J-mtFVB/N mice were employed. This conplastic inbred strain has been previously reported to exhibit decreased mitochondrial respiration likely linked to a non-synonymous gene variation (nt7778 G/T) of the mitochondrial ATP synthase protein 8 (mt-ATP8). Results At baseline conditions, C57BL/6J-mtFVB/N mice displayed hepatic mitochondrial dysfunction characterized by decreased ATP production and increased formation of reactive oxygen species (ROS). Moreover, genes affecting lipid metabolism were differentially expressed, hepatic triglyceride and cholesterol levels were changed in these animals, and various acyl-carnitines were altered, pointing towards an impaired mitochondrial carnitine shuttle. However, over a period of twelve months, no spontaneous hepatic steatosis or inflammation was observed. On the other hand, upon dietary challenge with either a methionine and choline deficient diet or a western-style diet, C57BL/6J-mtFVB/N mice developed aggravated steatohepatitis as characterized by lipid accumulation, ballooning of hepatocytes and infiltration of immune cells. Conclusions We observed distinct metabolic alterations in mice with a mitochondrial polymorphism associated hepatic mitochondrial dysfunction. However, a second hit, such as dietary stress, was required to cause hepatic steatosis and inflammation. This study suggests a causative role of hepatic mitochondrial dysfunction in the development of experimental NASH. AU - Schröder, T.* AU - Kucharczyk, D.* AU - Bär, F.* AU - Pagel, R.* AU - Derer, S.* AU - Jendrek, S.T.* AU - Sünderhauf, A.* AU - Brehack, A..-K.* AU - Hirose, M.* AU - Möller, S.* AU - Künstner, A.* AU - Bischof, A.* AU - Weyer, I.* AU - Heeren, J.* AU - Koczan, D.* AU - Schmid, S.M.* AU - Divanovic, S.* AU - Gieles, D.* AU - Adamski, J. AU - Fellermann, K.* AU - Lehnert, H.* AU - Köhl, J.* AU - Ibrahim, S.M.* AU - Sina, C.* C1 - 47846 C2 - 39543 SP - 283-295 TI - Mitochondrial gene polymorphisms alter hepatic cellular energy metabolism and aggravate diet-induced non-alcoholic steatohepatitis. JO - Mol. Metab. VL - 5 IS - 4 PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - BACKGROUND: Diabetes, obesity, and the metabolic syndrome are multifactorial diseases dependent on a complex interaction of host genetics, diet, and other environmental factors. Increasing evidence places gut microbiota as important modulators of the crosstalk between diet and development of obesity and metabolic dysfunction. In addition, host genetics can have important impact on the composition and function of gut microbiota. Indeed, depending on the genetic background of the host, diet and other environmental factors may produce different changes in gut microbiota, have different impacts on host metabolism, and create different interactions between the microbiome and the host. SCOPE OF REVIEW: In this review, we highlight how appropriate animal models can help dissect the complex interaction of host genetics with the gut microbiome and how diet can lead to different degrees of weight gain, levels of insulin resistance, and metabolic outcomes, such as diabetes, in different individuals. We also discuss the challenges of identifying specific disease-associated microbiota and the limitations of simple metrics, such as phylogenetic diversity or the ratio of Firmicutes to Bacteroidetes. MAJOR CONCLUSIONS: Understanding these complex interactions will help in the development of novel treatments for microbiome-related metabolic diseases. This article is part of a special issue on microbiota. AU - Ussar, S. AU - Fujisaka, S.* AU - Kahn, C.R.* C1 - 49467 C2 - 41993 CY - Amsterdam SP - 795-803 TI - Interactions between host genetics and gut microbiome in diabetes and metabolic syndrome. JO - Mol. Metab. VL - 5 IS - 9 PB - Elsevier Science Bv PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - Objective: Type 1 diabetes can be identified by the presence of beta-cell autoantibodies that often arise in the first few years of life. The purpose of this perspective is to present the case for primary prevention of beta-cell autoimmunity and to provide a study design for its implementation in Europe. Methods: We examined and summarized recruitment strategies, enrollment rates, and outcomes in published TRIGR, FINDIA and BABYDIET primary prevention trials, and the TEDDY intensive observational study. A proposal for a recruitment and implementation strategy to perform a phase II/III primary prevention randomized controlled trial in infants with genetic risk for developing beta-cell autoimmunity is outlined. Results: Infants with a family history of type 1 diabetes (TRIGR, BABYDIET, TEDDY) and infants younger than age 3 months from the general population (FINDIA, TEDDY) were enrolled into these studies. All studies used HLA genotyping as part of their eligibility criteria. Predicted beta-cell autoimmunity risk in the eligible infants ranged from 3% (FINDIA, TEDDY general population) up to 12% (TRIGR, BABYDIET). Amongst eligible infants, participation was between 38% (TEDDY general population) and 97% (FINDIA). Outcomes, defined as multiple beta-cell autoantibodies, were consistent with predicted risks. We subsequently modeled recruitment into a randomized controlled trial (RCT) that could assess the efficacy of oral insulin treatment as adapted from the Pre-POINT pilot trial. The RCT would recruit infants with and without a first-degree family history of type 1 diabetes and be based on general population genetic risk testing. HLA genotyping and, for the general population, genotyping at additional type 1 diabetes susceptibility SNPs would be used to identify children with around 10% risk of beta-cell autoimmunity. The proposed RCT would have 80% power to detect a 50% reduction in multiple beta-cell autoantibodies by age 4 years at a two-tailed alpha of 0.05, and would randomize around 1160 infants to oral insulin or placebo arms in order to fulfill this. It is estimated that recruitment would require testing of between 400,000 and 500,000 newborns or infants. Conclusion: It is timely and feasible to establish a platform for primary prevention trials for type 1 diabetes in Europe. This multi-site European infrastructure would perform RCTs, supply data coordination and biorepository, provide cohorts for mechanistic and observational studies, and increase awareness for autoimmune diabetes. AU - Ziegler, A.-G. AU - Danne, T.* AU - Dunger, D.B.* AU - Berner, R.* AU - Puff, R.* AU - Kiess, W.* AU - Agiostratidou, G.* AU - Todd, J.A.* AU - Bonifacio, E.* C1 - 48132 C2 - 39929 CY - Amsterdam SP - 255-262 TI - Primary prevention of beta-cell autoimmunity and type 1 diabetes - the Global Platform for the Prevention of Autoimmune Diabetes (GPPAD) perspectives. JO - Mol. Metab. VL - 5 IS - 4 PB - Elsevier Science Bv PY - 2016 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVES: Access to immortalized human pancreatic beta cell lines that are phenotypically close to genuine adult beta cells, represent a major tool to better understand human beta cell physiology and develop new therapeutics for Diabetes. Here we derived a new conditionally immortalized human beta cell line, EndoC-βH3 in which immortalizing transgene can be efficiently removed by simple addition of tamoxifen. METHODS: We used lentiviral mediated gene transfer to stably integrate a tamoxifen inducible form of CRE (CRE-ERT2) into the recently developed conditionally immortalized EndoC βH2 line. The resulting EndoC-βH3 line was characterized before and after tamoxifen treatment for cell proliferation, insulin content and insulin secretion. RESULTS: We showed that EndoC-βH3 expressing CRE-ERT2 can be massively amplified in culture. We established an optimized tamoxifen treatment to efficiently excise the immortalizing transgenes resulting in proliferation arrest. In addition, insulin expression raised by 12 fold and insulin content increased by 23 fold reaching 2 μg of insulin per million cells. Such massive increase was accompanied by enhanced insulin secretion upon glucose stimulation. We further observed that tamoxifen treated cells maintained a stable function for 5 weeks in culture. CONCLUSIONS: EndoC βH3 cell line represents a powerful tool that allows, using a simple and efficient procedure, the massive production of functional non-proliferative human beta cells. Such cells are close to genuine human beta cells and maintain a stable phenotype for 5 weeks in culture. AU - Benazra, M.* AU - Lecomte, M.J.* AU - Colace, C.* AU - Müller, A. AU - Machado, C.* AU - Pechberty, S.* AU - Bricout-Neveu, E.* AU - Grenier-Godard, M.* AU - Solimena, M. AU - Scharfmann, R.* AU - Czernichow, P.* AU - Ravassard, P.* C1 - 47971 C2 - 39810 SP - 916-925 TI - A human beta cell line with drug inducible excision of immortalizing transgenes. JO - Mol. Metab. VL - 4 IS - 12 PY - 2015 SN - 2212-8778 ER - TY - JOUR AB - Objective: Serum concentrations of the hepatokine fibroblast growth factor (FGF) 21 are elevated in obesity, type-2 diabetes, and the metabolic syndrome. We asked whether FGF21 levels differ between subjects with metabolically healthy vs. unhealthy obesity (MHO vs. MUHO), opening the possibility that FGF21 is a cross-talker between liver and adipose tissue in MUHO. Furthermore, we studied the effects of chronic FGF21 treatment on adipocyte differentiation, lipid storage, and adipokine secretion. Methods: In 20 morbidly obese donors of abdominal subcutaneous fat biopsies discordant for their whole-body insulin sensitivity (hereby classified as MHO or MUHO subjects), serum FGF21 was quantified. The impact of chronic FGF21 treatment on differentiation, lipid accumulation, and adipokine release was assessed in isolated preadipocytes differentiated invitro. Results: Serum FGF21 concentrations were more than two-fold higher in MUHO as compared to MHO subjects (457±378 vs. 211±123pg/mL; p<0.05). FGF21 treatment of human preadipocytes for the entire differentiation period was modestly lipogenic (+15%; p<0.05), reduced the expression of key adipogenic transcription factors (PPARG and CEBPA,-15% and-40%, respectively; p<0.01 both), reduced adiponectin expression (-20%; p<0.05), markedly reduced adiponectin release (-60%; p<0.01), and substantially increased leptin (+60%; p<0.01) and interleukin-6 (+50%; p<0.001) release. Conclusions: The hepatokine FGF21 exerts weak lipogenic and anti-adipogenic actions and marked adiponectin-suppressive and leptin and interleukin-6 release-promoting effects in human differentiating preadipocytes. Together with the higher serum concentrations in MUHO subjects, our findings reveal FGF21 as a circulating factor promoting the development of metabolically unhealthy adipocytes. AU - Berti, L. AU - Irmler, M. AU - Zdichavsky, M.* AU - Meile, T.* AU - Böhm, A. AU - Stefan, N. AU - Fritsche, A. AU - Beckers, J. AU - Königsrainer, A.* AU - Häring, H.-U. AU - Hrabě de Angelis, M. AU - Staiger, H. C1 - 44655 C2 - 36982 SP - 519-527 TI - Fibroblast growth factor 21 is elevated in metabolically unhealthy obesity and affects lipid deposition, adipogenesis, and adipokine secretion of human abdominal subcutaneous adipocytes. JO - Mol. Metab. VL - 4 IS - 7 PY - 2015 SN - 2212-8778 ER - TY - JOUR AB - Objective: Physical activity and circadian rhythms are well-established determinants of human health and disease, but the relationship between muscle activity and the circadian regulation of muscle genes is a relatively new area of research. It is unknown whether muscle activity and muscle clock rhythms are coupled together, nor whether activity rhythms can drive circadian gene expression in skeletal muscle. Methods: We compared the circadian transcriptomes of two mouse hindlimb muscles with vastly different circadian activity patterns, the continuously active slow soleus and the sporadically active fast tibialis anterior, in the presence or absence of a functional skeletal muscle clock (skeletal muscle-specific Bmal1 KO). In addition, we compared the effect of denervation on muscle circadian gene expression. Results: We found that different skeletal muscles exhibit major differences in their circadian transcriptomes, yet core clock gene oscillations were essentially identical in fast and slow muscles. Furthermore, denervation caused relatively minor changes in circadian expression of most core clock genes, yet major differences in expression level, phase and amplitude of many muscle circadian genes. Conclusions: We report that activity controls the oscillation of around 15% of skeletal muscle circadian genes independently of the core muscle clock, and we have identified the Ca2+-dependent calcineurin-NFAT pathway as an important mediator of activity-dependent circadian gene expression, showing that circadian locomotor activity rhythms drive circadian rhythms of NFAT nuclear translocation and target gene expression. AU - Dyar, K.A. AU - Ciciliot, S.* AU - Tagliazucchi, G.M.* AU - Pallafacchina, G.* AU - Tothova, J.* AU - Argentini, C.* AU - Agatea, L.* AU - Abraham, R.* AU - Ahdesmäki, M.* AU - Forcato, M.* AU - Bicciato, S.* AU - Schiaffino, S.* AU - Blaauw, B.* C1 - 47204 C2 - 40519 SP - 823-833 TI - The calcineurin-NFAT pathway controls activity-dependent circadian gene expression in slow skeletal muscle. JO - Mol. Metab. VL - 4 IS - 11 PY - 2015 SN - 2212-8778 ER - TY - JOUR AB - BACKGROUND & AIMS: Fibroblast growth factor 21 (FGF-21) is a liver-derived metabolic regulator induced by energy deprivation. However, its regulation in humans is incompletely understood. We addressed the origin and regulation of FGF-21 secretion in humans. METHODS: By determination of arterial-to-venous differences over the liver and the leg during exercise, we evaluated the organ-specific secretion of FGF-21 in humans. By four different infusion models manipulating circulating glucagon and insulin, we addressed the interaction of these hormones on FGF-21 secretion in humans. RESULTS: We demonstrate that the splanchnic circulation secretes FGF-21 at rest and that it is rapidly enhanced during exercise. In contrast, the leg does not contribute to the systemic levels of FGF-21. To unravel the mechanisms underlying the regulation of exercise-induced hepatic release of FGF-21, we manipulated circulating glucagon and insulin. These studies demonstrated that in humans glucagon stimulates splanchnic FGF-21 secretion whereas insulin has an inhibitory effect. CONCLUSIONS: Collectively, our data reveal that 1) in humans, the splanchnic bed contributes to the systemic FGF-21 levels during rest and exercise; 2) under normo-physiological conditions FGF-21 is not released from the leg; 3) a dynamic interaction of glucagon-to-insulin ratio regulates FGF-21 secretion in humans. AU - Hansen, J.S.* AU - Clemmesen, J.O.* AU - Secher, N.H.* AU - Hoene, M.* AU - Drescher, A.* AU - Weigert, C. AU - Pedersen, B.K.* AU - Plomgaard, P.* C1 - 46571 C2 - 37707 SP - 551-560 TI - Glucagon-to-insulin ratio is pivotal for splanchnic regulation of FGF-21 in humans. JO - Mol. Metab. VL - 4 IS - 8 PY - 2015 SN - 2212-8778 ER - TY - JOUR AB - OBJECTIVE: Glucagon-like peptide-1 (GLP-1) is released into the bloodstream after food intake. In addition to stimulating insulin release, it causes satiety and contributes to the termination of food intake. In this study, we investigated whether endogenous GLP-1 affects food-related brain activity and hunger. METHODS: Twenty-four volunteers (12 lean; 12 obese) underwent a 75 g oral glucose tolerance test that promotes GLP-1 secretion. Food cue-induced brain activity was assessed by functional magnetic resonance imaging and GLP-1 concentrations were measured before, 30, and 120 min after glucose intake. RESULTS: The significant increase in GLP-1 levels negatively correlated with a change in the food cue-induced brain activity in the orbitofrontal cortex, a major reward area. This association was independent of simultaneous alterations in insulin and glucose concentrations. The association was present in lean and overweight participants. By contrast, postprandial insulin changes were associated with orbitofrontal activations in lean individuals only. CONCLUSIONS: The postprandial release of GLP-1 might alter reward processes in the orbitofrontal cortex and might thereby support the termination of food intake and reduce hunger. While obese persons showed brain insulin resistance, no GLP-1 resistance was observed. Our study provides novel insight into the central regulation of food intake by the incretin hormone GLP-1. AU - Heni, M. AU - Kullmann, S. AU - Gallwitz, B.* AU - Häring, H.-U. AU - Preissl, H. AU - Fritsche, A. C1 - 47970 C2 - 39811 SP - 971-976 TI - Dissociation of GLP-1 and insulin association with food processing in the brain: GLP-1 sensitivity despite insulin resistance in obese humans. JO - Mol. Metab. VL - 4 IS - 12 PY - 2015 SN - 2212-8778 ER - TY - JOUR AB - In this issue of Molecular Metabolism, Dushay et al. report new results demonstrating fructose ingestion in humans acutely and robustly raises circulating levels of fibroblast growth factor 21 (FGF21) [1], a recently discovered hormone that has been proposed to have beneficial effects on metabolic health, including reduction of body weight and improvements of glucose and lipid metabolism [2]. People suffering from the metabolic syndrome have higher baseline circulating FGF21 levels and exhibit a larger increase of plasma FGF21 concentrations following an oral fructose load. AU - Hofmann, S.M. AU - Havel, P.J.* C1 - 43082 C2 - 35989 SP - 1-2 TI - The good, the bad, and the unknown: Fructose and FGF21. JO - Mol. Metab. VL - 4 IS - 1 PY - 2015 SN - 2212-8778 ER - TY - JOUR AB - Brown and beige adipose tissue may represent important therapeutic targets for the treatment of diabetes and obesity as these organs dissipate nutrient energy as heat through the thermogenic uncoupling protein 1 (UCP1). While mice are commonly used to mimic the potential effects of brown/beige adipose tissue that may act in human metabolism, new animal models are edging into the market for translational medicine. Pigs reflect human metabolism better than mice in multiple parameters such as obesity-induced hyperglycemia, cholesterol profiles and energy metabolism. Recently, it was reported that energy expenditure and body temperature in pigs is induced by the hormone leptin, and that leptin's action is mediated by UCP1 in adipose tissue. Given the tremendous importance of identifying molecular mechanisms for targeting therapeutics, we critically examine the evidence supporting the presence of UCP1 in pigs and conclude that methodological shortcomings prevent an unequivocal claim for the presence of UCP1 in pigs. Despite this, we believe that leptin's effects on energy expenditure in pigs are potentially more transformative to human medicine in the absence of UCP1, as adult and obese humans possess only minor amounts of UCP1. In general, we propose that the biology of new animal models requires attention to comparative studies with humans given the increasing amount of genomic information for various animal species. AU - Jastroch, M. AU - Andersson, L.B.* C1 - 43801 C2 - 36726 SP - 359-362 TI - When pigs fly, UCP1 makes heat. JO - Mol. Metab. VL - 4 IS - 5 PY - 2015 SN - 2212-8778 ER - TY - JOUR AB - Objective Excess lipid intake has been implicated in the pathophysiology of hepatosteatosis and hepatic insulin resistance. Lipids constitute approximately 50% of the cell membrane mass, define membrane properties, and create microenvironments for membrane-proteins. In this study we aimed to resolve temporal alterations in membrane metabolite and protein signatures during high-fat diet (HF)-mediated development of hepatic insulin resistance. Methods We induced hepatosteatosis by feeding C3HeB/FeJ male mice a HF enriched with long-chain polyunsaturated C18:2n6 fatty acids for 7, 14, or 21 days. Longitudinal changes in hepatic insulin sensitivity were assessed via the euglycemic-hyperinsulinemic clamp, in membrane lipids via t-metabolomics- and membrane proteins via quantitative proteomics-analyses, and in hepatocyte morphology via electron microscopy. Data were compared to those of age- and litter-matched controls maintained on a low-fat diet. Results Excess long-chain polyunsaturated C18:2n6 intake for 7 days did not compromise hepatic insulin sensitivity, however induced hepatosteatosis and modified major membrane lipid constituent signatures in liver, e.g. increased total unsaturated, long-chain fatty acid-containing acyl-carnitine or membrane-associated diacylglycerol moieties and decreased total short-chain acyl-carnitines, glycerophosphocholines, lysophosphatidylcholines, or sphingolipids. Hepatic insulin sensitivity tended to decrease within 14 days HF-exposure. Overt hepatic insulin resistance developed until day 21 of HF-intervention and was accompanied by morphological mitochondrial abnormalities and indications for oxidative stress in liver. HF-feeding progressively decreased the abundance of protein-components of all mitochondrial respiratory chain complexes, inner and outer mitochondrial membrane substrate transporters independent from the hepatocellular mitochondrial volume in liver. Conclusions We assume HF-induced modifications in membrane lipid- and protein-signatures prior to and during changes in hepatic insulin action in liver alter membrane properties – in particular those of mitochondria which are highly abundant in hepatocytes. In turn, a progressive decrease in the abundance of mitochondrial membrane proteins throughout HF-exposure likely impacts on mitochondrial energy metabolism, substrate exchange across mitochondrial membranes, contributes to oxidative stress, mitochondrial damage, and the development of insulin resistance in liver. AU - Kahle-Stephan, M. AU - Schäfer, A. AU - Seelig, A. AU - Schultheiß, J. AU - Wu, M. AU - Aichler, M. AU - Leonhardt, J. AU - Rathkolb, B. AU - Rozman, J. AU - Sarioglu, H. AU - Hauck, S.M. AU - Ueffing, M. AU - Wolf, E. AU - Kastenmüller, G. AU - Adamski, J. AU - Walch, A.K. AU - Hrabě de Angelis, M. AU - Neschen, S. C1 - 42765 C2 - 35321 SP - 39-50 TI - High fat diet-induced modifications in membrane lipid and mitochondrial-membrane protein signatures precede the development of hepatic insulin resistance in mice. JO - Mol. Metab. VL - 4 IS - 1 PY - 2015 SN - 2212-8778 ER - TY - JOUR AB - Objective: Circulating fibroblast growth factor 21 (FGF21) is an important auto- and endocrine player with beneficial metabolic effects on obesity and diabetes. In humans, thermogenic brown adipose tissue (BAT) was recently suggested as a source of FGF21 secretion during cold exposure. Here, we aim to clarify the role of UCP1 and ambient temperature in the regulation of FGF21 in mice. Methods: Wildtype (WT) and UCP1-knockout (UCP1 KO) mice, the latter being devoid of BAT-derived non-shivering thermogenesis, were exposed to different housing temperatures. Plasma metabolites and FGF21 levels were determined, gene expression was analyzed by qPCR, and tissue histology was performed with adipose tissue. Results: At thermoneutrality, FGF21 gene expression and serum levels were not different between WT and UCP1 KO mice. Cold exposure led to highly increased FGF21 serum levels in UCP1 KO mice, which were reflected in increased FGF21 gene expression in adipose tissues but not in liver and skeletal muscle. Exvivo secretion assays revealed FGF21 release only from BAT, progressively increasing with decreasing ambient temperatures. In association with increased FGF21 serum levels in the UCP1 KO mouse, typical FGF21-related serum metabolites and inguinal white adipose tissue morphology and thermogenic gene expression were altered. Conclusions: Here we show that the genetic ablation of UCP1 increases FGF21 gene expression in adipose tissue. The removal of adaptive nonshivering thermogenesis renders BAT a significant source of endogenous FGF21 under thermal stress. Thus, the thermogenic competence of BAT is not a requirement for FGF21 secretion. Notably, high endogenous FGF21 levels in UCP1-deficient models and subjects may confound pharmacological FGF21 treatments. AU - Keipert, S. AU - Kutschke, M. AU - Lamp, D. AU - Brachthäuser, L. AU - Neff, F. AU - Meyer, C.W. AU - Oelkrug, R.* AU - Kharitonenkov, A.* AU - Jastroch, M. C1 - 45068 C2 - 37219 SP - 537-542 TI - Genetic disruption of uncoupling protein 1 in mice renders brown adipose tissue a significant source of FGF21 secretion. JO - Mol. Metab. VL - 4 IS - 7 PY - 2015 SN - 2212-8778 ER - TY - JOUR AU - Migliorini, A. AU - Lickert, H. C1 - 44097 C2 - 37631 SP - 365-366 TI - Beyond association: A functional role for Tcf7l2 in β-cell development. JO - Mol. Metab. VL - 4 IS - 5 PY - 2015 SN - 2212-8778 ER - TY - JOUR AB - Background: The gastrointestinal peptide hormone ghrelin was discovered in 1999 as the endogenous ligand of the growth hormone secretagogue receptor. Increasing evidence supports more complicated and nuanced roles for the hormone, which go beyond the regulation of systemic energy metabolism. Scope of review: In this review, we discuss the diverse biological functions of ghrelin, the regulation of its secretion, and address questions that still remain 15 years after its discovery. Major conclusions: In recent years, ghrelin has been found to have a plethora of central and peripheral actions in distinct areas including learning and memory, gut motility and gastric acid secretion, sleep/wake rhythm, reward seeking behavior, taste sensation and glucose metabolism. AU - Müller, T.D. AU - Nogueiras, R.A.* AU - Andermann, M.L.* AU - Andrews, Z.B.* AU - Anker, S.D.* AU - Argente, J.* AU - Batterham, R.* AU - Benoit, S.C.* AU - Bowers, C.Y.* AU - Broglio, F.* AU - Casanueva, F.F.F.* AU - D'Alessio, D.* AU - Depoortere, I.* AU - Geliebter, A.A.* AU - Ghigo, E.* AU - Cole, P.A.* AU - Cowley, M.A.* AU - Cummings, D.E.* AU - Dagher, A.* AU - Diano, S.* AU - Dickson, S.L.* AU - Dieguez, C.* AU - Granata, R.* AU - Grill, H.J.* AU - Grove, K.L.* AU - Habegger, K.M.* AU - Heppner, K.M.* AU - Heiman, M.L.* AU - Holsen, L.* AU - Holst, B.* AU - Inui, A.* AU - Jansson, J.O.* AU - Kirchner, H.* AU - Korbonits, M.* AU - Laferrère, B.* AU - LeRoux, C.W.* AU - López, M.D.* AU - Morin, S. AU - Nakazato, M.* AU - Nass, R.* AU - Perez-Tilve, D.* AU - Pfluger, P.T. AU - Schwartz, T.W.* AU - Seeley, R.J.* AU - Sleeman, M.W.* AU - Sun, Y.* AU - Sussel, L.* AU - Tong, J.* AU - Thorner, M.O.* AU - van der Lely, A.J.* AU - van der Ploeg, L.H.T.* AU - Zigman, J.M.* AU - Kojima, M.* AU - Kangawa, K.* AU - Smith, R.G.* AU - Horvath, T.* AU - Tschöp, M.H. C1 - 44424 C2 - 36919 SP - 437–460 TI - Ghrelin. JO - Mol. Metab. VL - 4 IS - 6 PY - 2015 SN - 2212-8778 ER - TY - JOUR AB - Objective: One of the major side effects of glucocorticoid (GC) treatment is lean tissue wasting, indicating a prominent role in systemic amino acid metabolism. In order to uncover a novel aspect of GCs and their intracellular-receptor, the glucocorticoid receptor (GR), on metabolic control, we conducted amino acid and acylcarnitine profiling in human and mouse models of GC/GR gain- and loss-of-function. Methods: Blood serum and tissue metabolite levels were determined in Human Addison's disease (AD) patients as well as in mouse models of systemic and liver-specific GR loss-of-function (AAV-miR-GR) with or without dexamethasone (DEX) treatments. Body composition and neuromuscular and metabolic function tests were conducted invivo and exvivo, the latter using precision cut liver slices. Results: A serum metabolite signature of impaired urea cycle function (i.e. higher [ARG]:[ORN+CIT]) was observed in human (CTRL: 0.45±0.03, AD: 1.29±0.04; p<0.001) and mouse (AAV-miR-NC: 0.97±0.13, AAV-miR-GR: 2.20±0.19; p<0.001) GC/GR loss-of-function, with similar patterns also observed in liver. Serum urea levels were consistently affected by GC/GR gain- (~+32%) and loss (~-30%) -of-function. Combined liver-specific GR loss-of-function with DEX treatment revealed a tissue-autonomous role for the GR to coordinate an upregulation of liver urea production rate invivo and exvivo, and prevent hyperammonaemia and associated neuromuscular dysfunction invivo. Liver mRNA expression profiling and GR-cistrome mining identified Arginase I (ARG1) a urea cycle gene targeted by the liver GR. Conclusions: The liver GR controls systemic and liver urea cycle function by transcriptional regulation of ARG1 expression. AU - Okun, J.G.* AU - Conway, S.* AU - Schmidt, K.V.* AU - Schumacher, J.* AU - Wang, X.* AU - de Guia, R.* AU - Zota, A. AU - Klement, J.* AU - Seibert, O.* AU - Peters, A.* AU - Maida, A. AU - Herzig, S. AU - Rose, A.J.* C1 - 46683 C2 - 37691 SP - 732-740 TI - Molecular regulation of urea cycle function by the liver glucocorticoid receptor. JO - Mol. Metab. VL - 4 IS - 10 PY - 2015 SN - 2212-8778 ER - TY - JOUR AU - Schriever, S.C. AU - Pfluger, P.T. C1 - 43962 C2 - 36715 SP - 363–364 TI - Setting the TRAP for central leptin targets. JO - Mol. Metab. VL - 4 IS - 5 PY - 2015 SN - 2212-8778 ER - TY - JOUR AU - Fischer, K. AU - Müller, T.D. C1 - 31095 C2 - 34124 SP - 217-218 TI - Relationship status update for PTP1B and LepR: It׳s complicated. JO - Mol. Metab. VL - 3 IS - 3 PY - 2014 SN - 2212-8778 ER - TY - JOUR AB - Variation in FTO is the strongest genetic determinant of body weight and has recently been linked with impaired neural processing of food stimuli. However, whether this brain-expressed gene affects neuronal processing of food-related stimuli after ingestion is still poorly understood. In this study, twenty-four participants were examined before, 30 and 120 min after ingesting 75 g of glucose solution or water on two separate days. Functional magnetic resonance imaging (fMRI) during visual food presentation was performed. All participants were genotyped for FTO SNP rs8050136. We detected significant differences between FTO genotypes in the prefrontal cortex 30 min post-glucose load in BOLD-response to food pictures (p=0.0017), while no differences were detected in response to water ingestion or 120 min post-glucose load. Since the prefrontal cortex plays a major role in the inhibitory control of eating, we propose that reduced postprandial activity in FTO risk allele carriers contributes to overeating and obesity. AU - Heni, M. AU - Kullmann, S. AU - Veit, R.* AU - Ketterer, C. AU - Frank, S.* AU - Machicao, F. AU - Staiger, H. AU - Häring, H.-U. AU - Preissl, H. AU - Fritsche, A. C1 - 30865 C2 - 33991 SP - 109-113 TI - Variation in the obesity risk gene FTO determines the postprandial cerebral processing of food stimuli in the prefrontal cortex. JO - Mol. Metab. VL - 3 IS - 2 PY - 2014 SN - 2212-8778 ER - TY - JOUR AU - Jastroch, M. AU - Keipert, S. AU - Perocchi, F. C1 - 30630 C2 - 33757 SP - 86-87 TI - From explosives to physiological combustion: Next generation chemical uncouplers. JO - Mol. Metab. VL - 3 IS - 2 PY - 2014 SN - 2212-8778 ER - TY - JOUR AU - Kotzbeck, P. AU - Zechner, R.* C1 - 30864 C2 - 33992 SP - 88-89 TI - Angiopoietin-like 4: An endogenous break of intestinal lipid digestion. JO - Mol. Metab. VL - 3 IS - 2 PY - 2014 SN - 2212-8778 ER - TY - JOUR AB - Insulin-dependent diabetes is a complex multifactorial disorder characterized by loss or dysfunction of β-cells resulting in failure of metabolic control. Even though type 1 and 2 diabetes differ in their pathogenesis, restoring β-cell function is the overarching goal for improved therapy of both diseases. This could be achieved either by cell-replacement therapy or by triggering intrinsic regenerative mechanisms of the pancreas. For type 1 diabetes, a combination of β-cell replacement and immunosuppressive therapy could be a curative treatment, whereas for type 2 diabetes enhancing endogenous mechanisms of β-cell regeneration might optimize blood glucose control. This review will briefly summarize recent efforts to allow β-cell regeneration where the most promising approaches are currently (1) increasing β-cell self-replication or neogenesis from ductal progenitors and (2) conversion of α-cells into β-cells. AU - Migliorini, A. AU - Bader, E. AU - Lickert, H. C1 - 30629 C2 - 33759 SP - 268–274 TI - Islet cell plasticity and regeneration. JO - Mol. Metab. VL - 3 IS - 3 PY - 2014 SN - 2212-8778 ER - TY - JOUR AB - Gestational diabetes mellitus (GDM) increases the future risk of developing type 2 diabetes mellitus (T2DM). There is now a growing evidence that breastfeeding has short- and long-term health benefits for mothers with GDM. Mothers with GDM who breastfeed have improved lipid and glucose metabolic profiles for the first 3 months after birth. However, women with GDM are less likely to breastfeed and, if they do, breastfeeding is usually continued for a shorter duration compared with women without GDM. One long-term prospective study followed women with GDM from delivery for up to 19 years postpartum, and found that breastfeeding for ≥3 months reduced the risk of T2DM and delayed the development of T2DM by a further 10 years compared with breastfeeding for <3 months. However, the physiological mechanisms underlying the protective effects of breastfeeding are still unknown, even though it is important to gain a full understanding of the pathways involved in these effects. Therefore, the purpose of this review is to provide a comprehensive analysis of the recent developments in the field of GDM and breastfeeding. We reviewed data from animal experiments and human studies. We also provide insight into the molecular pathways and describe promising topics for future research. AU - Much, D. AU - Beyerlein, A. AU - Roßbauer, M. AU - Hummel, S. AU - Ziegler, A.-G. C1 - 31093 C2 - 34125 SP - 284-292 TI - Beneficial effects of breastfeeding in women with gestational diabetes mellitus. JO - Mol. Metab. VL - 3 IS - 3 PY - 2014 SN - 2212-8778 ER - TY - JOUR AU - Uhlenhaut, N.H. C1 - 30863 C2 - 33993 SP - 92-93 TI - Mix 'n' match estrogens. JO - Mol. Metab. VL - 3 IS - 2 PY - 2014 SN - 2212-8778 ER - TY - JOUR AU - Ussar, S. C1 - 30701 C2 - 33820 SP - 219–220 TI - Linking maternal obesity to early insulin resistance. JO - Mol. Metab. VL - 3 IS - 3 PY - 2014 SN - 2212-8778 ER - TY - JOUR AB - Deteriorating beta-cell function is a common feature of type 2 diabetes. In this review, we briefly address the regulation of beta-cell function, and discuss some of the main determinants of beta-cell failure. We will focus on the role of interactions between the genetic background and metabolic environment (insulin resistance, fuel supply and flux as well as metabolic signaling). We present data on the function of the strongest common diabetes risk variant, the single nucleotide polymorphism (SNP) rs7903146 in TCF7L2. As also mirrored by its interaction with glycemia on insulin secretion, this SNP in large part confers resistance against the incretin effect. Genetic influence on insulin secretion also interacts with free fatty acids, as evidenced by data on rs1573611 in FFAR1. Several medications marketed by now or currently under development for diabetes treatment engage these pathways, and therapeutic implications from these findings are soon to be expected. AU - Wagner, R.* AU - Staiger, H. AU - Ullrich, S. AU - Stefan, N. AU - Fritsche, A. AU - Häring, H.-U. C1 - 31094 C2 - 34123 SP - 261-267 TI - Untangling the interplay of genetic and metabolic influences on beta-cell function: Examples of potential therapeutic implications involving TCF7L2 and FFAR1. JO - Mol. Metab. VL - 3 IS - 3 PY - 2014 SN - 2212-8778 ER - TY - JOUR AB - Genetic variation in FFAR1 modulates insulin secretion dependent on non-esterified fatty acid (NEFA) concentrations. We previously demonstrated lower insulin secretion in minor allele carriers of PPARG Pro12Ala in high-NEFA environment, but the mode of action could not been revealed. We tested if this effect is mediated by FFAR1 in humans. Subjects with increased risk of diabetes who underwent oral glucose tolerance tests were genotyped for 7 tagging SNPs in FFAR1 and PPARG Pro12Ala. The FFAR1 SNPs rs12462800 and rs10422744 demonstrated interactions with PPARG on insulin secretion. FFAR1 rs12462800 (p = 0.0006) and rs10422744 (p = 0.001) were associated with reduced insulin secretion in participants concomitantly carrying the PPARG minor allele and having high fasting FFA. These results suggest that the minor allele of the PPARG SNP exposes its carriers to modulatory effects of FFAR1 on insulin secretion. This subphenotype may define altered responsiveness to FFAR1-agonists, and should be investigated in further studies. AU - Wagner, R. AU - Hieronimus, A. AU - Lamprinou, A. AU - Heni, M. AU - Hatziagelaki, E.* AU - Ullrich, S. AU - Stefan, N. AU - Staiger, H. AU - Häring, H.-U. AU - Fritsche, A. C1 - 32041 C2 - 34948 SP - 676-680 TI - Peroxisome Proliferator-Activated Receptor Gamma (PPARG) modulates Free Fatty Acid Receptor 1 (FFAR1) dependent insulin secretion in humans. JO - Mol. Metab. VL - 3 IS - 6 PY - 2014 SN - 2212-8778 ER - TY - JOUR AB - Alterations in the gut microbiota have been proposed to modify the development and maintenance of obesity and its sequelae. Definition of underlying mechanisms has lagged, although the ability of commensal gut microbes to drive pathways involved in inflammation and metabolism has generated compelling, testable hypotheses. We studied C57BL/6 mice from two vendors that differ in their obesogenic response and in their colonization by specific members of the gut microbiota having well-described roles in regulating gut immune responses. We confirmed the presence of robust differences in weight gain in mice from these different vendors during high fat diet stress. However, neither specific, highly divergent members of the gut microbiota (Lactobacillus murinus, segmented filamentous bacteria) nor the horizontally transmissible gut microbiota were found to be responsible. Constitutive differences in locomotor activity were observed, however. These data underscore the importance of selecting appropriate controls in this widely used model of human obesity. AU - Harley, I.T.* AU - Giles, D.A.* AU - Pfluger, P.T. AU - Burgess, S.L.* AU - Walters, S.* AU - Hembree, J.* AU - Raver, C.* AU - Rewerts, C.L.* AU - Downey, J.* AU - Flick, L.M.* AU - Stankiewicz, T.E.* AU - McAlees, J.W.* AU - Wills-Karp, M.* AU - Balfour Sartor, R.* AU - Divanovic, S.* AU - Tschöp, M.H. AU - Karp, C.L.* C1 - 28192 C2 - 33004 SP - 171-183 TI - Differential colonization with segmented filamentous bacteria and Lactobacillus murinus do not drive divergent development of diet-induced obesity in C57BL/6 mice. JO - Mol. Metab. VL - 2 IS - 3 PB - Elsevier PY - 2013 SN - 2212-8778 ER - TY - JOUR AB - Genetic predisposition and environmental factors contribute to an individual's susceptibility to develop hepatosteatosis. In a systematic, comparative survey we focused on genotype-dependent and -independent adaptations early in the pathogenesis of hepatosteatosis by characterizing C3HeB/FeJ, C57BL/6NTac, C57BL/6J, and 129P2/OlaHsd mice after 7, 14, or 21 days high-fat-diet exposure. Strain-specific metabolic responses during diet challenge and liver transcript signatures in mild hepatosteatosis outline the suitability of particular strains for investigating the relationship between hepatocellular lipid content and inflammation, glucose homeostasis, insulin action, or organelle physiology. Genetic background-independent transcriptional adaptations in liver paralleling hepatosteatosis suggest an early increase in the organ's vulnerability to oxidative stress damage what could advance hepatosteatosis to steatohepatitis. “Universal“ adaptations in transcript signatures and transcription factor regulation in liver link insulin resistance, type 2 diabetes mellitus, cancer, and thyroid hormone metabolism with hepatosteatosis, hence, facilitating the search for novel molecular mechanisms potentially implicated in the pathogenesis of human non-alcoholic-fatty-liver-disease. AU - Kahle-Stephan, M. AU - Horsch, M. AU - Fridrich, B. AU - Seelig, A. AU - Schultheiß, J. AU - Leonhardt, J. AU - Irmler, M. AU - Beckers, J. AU - Rathkolb, B. AU - Wolf, E.* AU - Franke, N. AU - Gailus-Durner, V. AU - Fuchs, H. AU - Hrabě de Angelis, M. AU - Neschen, S. C1 - 26581 C2 - 32280 SP - 435-446 TI - Phenotypic comparison of common mouse strains developing high-fat diet-induced hepatosteatosis. JO - Mol. Metab. VL - 2 IS - 4 PB - Elsevier PY - 2013 SN - 2212-8778 ER - TY - JOUR AB - B-cell failure at the onset of type 2 diabetes is caused by a decline in β-cell function in the postprandial state and loss of pancreatic β-cell mass. Recently, we showed an association between increased insulin secretion and a single nucleotide polymorphism (SNP), SNP rs12686676, in the NR4A3 gene locus encoding the nuclear receptor Nor-1. Nor-1 is expressed in β-cells, however, not much is known about its function with regard to insulin gene expression and insulin secretion. Nor-1 is induced in a glucose-/incretin-dependent manner via the PKA pathway and directly induces insulin gene expression. Additionally, it stimulates insulin secretion possibly via regulation of potentially important genes in insulin exocytosis. Moreover, we show that the minor allele of NR4A3 SNP rs12686676 fully rescues incretin resistance provoked by a well-described polymorphism in TCF7L2. Thus, Nor-1 represents a promising new target for pharmacological intervention to fight diabetes. AU - Ordelheide, A.-M. AU - Gerst, F.* AU - Rothfuss, O.* AU - Heni, M.* AU - Haas, C. AU - Thielker, I. AU - Herzberg-Schäfer, S.* AU - Böhm, A. AU - Machicao, F. AU - Ullrich, S. AU - Stefan, N. AU - Fritsche, A. AU - Häring, H.-U. AU - Staiger, H. C1 - 28732 C2 - 33531 SP - 243-255 TI - Nor-1, a novel incretin-responsive regulator of insulin genes and insulin secretion. JO - Mol. Metab. VL - 2 IS - 3 PB - Elsevier PY - 2013 SN - 2212-8778 ER - TY - JOUR AB - Medicines that decrease body weight and restore nutrient tolerance could improve human diabetes and obesity treatment outcomes. We developed lipid-acylated glucagon analogs that are co-agonists for the glucagon and glucagon-like peptide 1 receptors, and stimulate weight loss and plasma glucose lowering in pre-diabetic obese mice. Our studies identified lipid acylation (lipidation) can increase and balance in vitro potencies of select glucagon analogs for the two aforementioned receptors in a lipidation site-dependent manner. A general capacity for lipidation to enhance the secondary structure of glucagon analogs was recognized, and the energetics of this effect quantified. The molecular structure of a lipid-acylated glucagon analog in water was also characterized. These results support that lipidation can modify biological activity through thermodynamically-favorable intramolecular interactions which stabilize structure. This establishes use of lipidation to achieve specific pharmacology and implicates similar endogenous post-translational modifications as physiological tools capable of refining biological action in means previously underappreciated. AU - Ward, B.P.* AU - Ottaway, N.L.* AU - Perez-Tilve, D.* AU - Ma, D.* AU - Gelfanov, V.M.* AU - Tschöp, M.H. AU - DiMarchi, R.D.* C1 - 28718 C2 - 33514 SP - 468-479 TI - Peptide lipidation stabilizes structure to enhance biological function. JO - Mol. Metab. VL - 2 IS - 4 PB - Elsevier PY - 2013 SN - 2212-8778 ER - TY - JOUR AU - Yi, C.-X. AU - Meyer, C.W. AU - Jastroch, M. C1 - 26258 C2 - 32148 SP - 63-64 TI - Leptin action in the brain: How (and when) it makes fat burn. JO - Mol. Metab. VL - 2 IS - 2 PB - Elsevier PY - 2013 SN - 2212-8778 ER - TY - JOUR AB - Glia are the most abundant cell type in the brain and are indispensible for the normal execution of neuronal actions. They protect neurons from noxious insults and modulate synaptic transmission through affectation of synaptic inputs, release of glial transmitters and uptake of neurotransmitters from the synaptic cleft. They also transport nutrients and other circulating factors into the brain thus controlling the energy sources and signals reaching neurons. Moreover, glia express receptors for metabolic hormones, such as leptin and insulin, and can be activated in response to increased weight gain and dietary challenges. However, chronic glial activation can be detrimental to neurons, with hypothalamic astrocyte activation or gliosis suggested to be involved in the perpetuation of obesity and the onset of secondary complications. It is now accepted that glia may be a very important participant in metabolic control and a possible therapeutical target. Here we briefly review this rapidly advancing field. AU - García-Cáceres, C. AU - Fuente-Martin, E.* AU - Argente, J.* AU - Chowen, J.A.* C1 - 11125 C2 - 30509 SP - 37-46 TI - Emerging role of glial cells in the control of body weight. JO - Mol. Metab. VL - 1 IS - 1-2 PB - Elsevier PY - 2012 SN - 2212-8778 ER - TY - JOUR AB - Obesity, type 2 diabetes, and related diseases represent major health threats to modern society. Related pathophysiology of impaired neuronal function in hypothalamic control centers regulating metabolism and body weight has been dissected extensively and recent studies have started focusing on potential roles of astrocytes and microglia. The hypothalamic vascular system, however, which maintains the microenvironment necessary for appropriate neuronal function, has been largely understudied. We recently discovered that high fat/high sucrose diet exposure leads to increased hypothalamic presence of immunoglobulin G (IgG1). Investigating this phenomenon further, we have discovered a significant increase in blood vessel length and density in the arcuate nucleus (ARC) of the hypothalamus in mice fed a high fat/high sucrose diet, compared to matched controls fed standard chow diet. We also found a clearly increased presence of α-smooth muscle actin immunoreactive vessels, which are rarely present in the ARC and indicate an increase in the formation of new arterial vessels. Along the blood brain barrier, an increase of degenerated endothelial cells are observed. Moreover, such hypothalamic angiogenesis was not limited to rodent models. We also found an increase in the number of arterioles of the infundibular nucleus (the human equivalent of the mouse ARC) in patients with type 2 diabetes, suggesting angiogenesis occurs in the human hypothalamus of diabetics. Our discovery reveals novel hypothalamic pathophysiology, which is reminiscent of diabetic retinopathy and suggests a potential functional involvement of the hypothalamic vasculature in the later stage pathogenesis of metabolic syndrome. AU - Yi, C.-X. AU - Gericke, M.* AU - Krüger, M.* AU - Alkemade, A.* AU - Kabra, D.G. AU - Hanske, S.* AU - Filosa, J.* AU - Pfluger, P.T. AU - Bingham, N.* AU - Woods, S.C.* AU - Herman, J.* AU - Kalsbeek, A.* AU - Baumann, M.* AU - Lang, R.* AU - Stern, J.E.* AU - Bechmann, I.* AU - Tschöp, M.H. C1 - 11139 C2 - 30515 SP - 95-100 TI - High calorie diet triggers hypothalamic angiopathy. JO - Mol. Metab. VL - 1 IS - 1-2 PB - Elsevier PY - 2012 SN - 2212-8778 ER -