TY  - JOUR
AB  - The highly conserved CHCHD2 and CHCHD10 are small mitochondrial proteins residing in the intermembrane space. Recently, mutations in the genes encoding these proteins have been linked to severe disorders, including Parkinson's disease and amyotrophic lateral sclerosis. In cultured cells, a small fraction of CHCHD2 and CHCHD10 oligomerize to form a high molecular weight complex of unknown function. Here, we generated a whole-body Chchd2 knockout mouse to investigate the in vivo role of CHCHD2 and its protein complex. We show that CHCHD2 is crucial for sustaining full motor capacity, normal striatal dopamine levels, and lipid homeostasis in the brain of adult male mice. We also demonstrate that in mouse tissues, CHCHD2 and CHCHD10 exist exclusively as a high molecular weight complex, whose levels are finely tuned under physiological conditions. In response to mitochondrial dysfunction, the abundance and size of the CHCHD2-CHCHD10 complex increase, a mechanism conserved across different tissues. Although the loss of CHCHD2 does not abolish CHCHD10 oligomerization, it enhances cell vulnerability to mitochondrial stress, suggesting that CHCHD2 is protective against mitochondrial damage. Our findings uncover the role of CHCHD2 in preserving tissue homeostasis and provide important insights into the involvement of the CHCHD2-CHCHD10 complex in human diseases.
AU  - Gerlach, J.*
AU  - Pireddu, P.*
AU  - Zhang, X.*
AU  - Wetzel, S.*
AU  - Mennuni, M.*
AU  - Milenkovic, D.*
AU  - Nolte, H.*
AU  - da Silva Rodrigues, F.*
AU  - Branzell, N.*
AU  - Kaya, I.*
AU  - Villegas, R.G.*
AU  - Rubalcava-Gracia, D.*
AU  - Alsina, D.*
AU  - Feederle, R.
AU  - Andrén, P.E.*
AU  - Langer, T.*
AU  - Svenningsson, P.*
AU  - Filograna, R.*
C1  - 75723
C2  - 57981
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - The CHCHD2-CHCHD10 protein complex is modulated by mitochondrial dysfunction and alters lipid homeostasis in the mouse brain.
JO  - Cell Death Dis.
VL  - 16
IS  - 1
PB  - Springernature
PY  - 2025
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Creatine (Cr) is essential for cellular energy homeostasis, particularly in muscle and brain tissues. Creatine Transporter Deficiency (CTD), an X-linked disorder caused by mutations in the SLC6A8 gene, disrupts Cr transport, leading to intellectual disability, speech delay, autism, epilepsy, and various non-neurological symptoms. In addition to neurological alterations, Creatine Transporter knockout (CrT-/y) mice exhibit severe muscle atrophy and functional impairments. This study provides the first characterization of the skeletal muscle phenotype in CrT-/y mice, revealing profound ultrastructural abnormalities accompanied by reduced fiber cross-sectional area and muscle performance. Notably, mitochondria are involved, as evidenced by disrupted cristae, increased mitochondrial size, impaired Ca2+ uptake, reduced membrane potential and ATP production. Mechanistically, the expression of atrophy-specific E3 ubiquitin ligases and suppression of the IGF1-Akt/PKB pathway, regulated by mitochondrial Ca2+ levels, further support the atrophic phenotype. These findings highlight the profound impact of Cr deficiency on skeletal muscle, emphasizing the need for targeted therapeutic strategies to address both the neurological and peripheral manifestations of CTD. Understanding the underlying mechanisms, particularly mitochondrial dysfunction, could lead to novel interventions for this disorder.
AU  - Pertici, I.*
AU  - D'Angelo, D.*
AU  - Vecellio Reane, D.
AU  - Reconditi, M.*
AU  - Morotti, I.*
AU  - Putignano, E.*
AU  - Napoli, D.*
AU  - Rastelli, G.*
AU  - Gherardi, G.*
AU  - De Mario, A.*
AU  - Rizzuto, R.*
AU  - Boncompagni, S.*
AU  - Baroncelli, L.*
AU  - Linari, M.*
AU  - Caremani, M.*
AU  - Raffaello, A.*
C1  - 73391
C2  - 57042
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - Creatine transporter (SLC6A8) knockout mice exhibit reduced muscle performance, disrupted mitochondrial Ca2+ homeostasis, and severe muscle atrophy.
JO  - Cell Death Dis.
VL  - 16
IS  - 1
PB  - Springernature
PY  - 2025
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Metabolic aberrations are fundamental to the complex pathophysiology and challenges associated with diabetic wound healing. These alterations, induced by the diabetic environment, trigger a cascade of events that disrupt the normal wound-healing process. Key factors in this metabolic alternation include chronic hyperglycemia, insulin resistance, and dysregulated lipid and amino acid metabolism. In this review, we summarize the underlying mechanisms driving these metabolic changes in diabetic wounds, while emphasizing the broad implications of these disturbances. Additionally, we discuss therapeutic approaches that target these metabolic anomalies and how their integration with existing wound-healing treatments may yield synergistic effects, offering promising avenues for innovative therapies.
AU  - Xiong, Y.*
AU  - Knoedler, S.
AU  - Alfertshofer, M.*
AU  - Kim, B.S.*
AU  - Jiang, D.*
AU  - Liu, G.*
AU  - Rinkevich, Y.
AU  - Mi, B.*
C1  - 74204
C2  - 57372
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - Mechanisms and therapeutic opportunities in metabolic aberrations of diabetic wounds: A narrative review.
JO  - Cell Death Dis.
VL  - 16
IS  - 1
PB  - Springernature
PY  - 2025
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - The progression of human degenerative and hypoxic/ischemic diseases is accompanied by widespread cell death. One death process linking iron-catalyzed reactive species with lipid peroxidation is ferroptosis, which shows hallmarks of both programmed and necrotic death in vitro. While evidence of ferroptosis in neurodegenerative disease is indicated by iron accumulation and involvement of lipids, a stable marker for ferroptosis has not been identified. Its prevalence is thus undetermined in human pathophysiology, impeding recognition of disease areas and clinical investigations with candidate drugs. Here, we identified ferroptosis marker antigens by analyzing surface protein dynamics and discovered a single protein, Fatty Acid-Binding Protein 5 (FABP5), which was stabilized at the cell surface and specifically elevated in ferroptotic cell death. Ectopic expression and lipidomics assays demonstrated that FABP5 drives redistribution of redox-sensitive lipids and ferroptosis sensitivity in a positive-feedback loop, indicating a role as a functional biomarker. Notably, immunodetection of FABP5 in mouse stroke penumbra and in hypoxic postmortem patients was distinctly associated with hypoxically damaged neurons. Retrospective cell death characterized here by the novel ferroptosis biomarker FABP5 thus provides first evidence for a long-hypothesized intrinsic ferroptosis in hypoxia and inaugurates a means for pathological detection of ferroptosis in tissue.
AU  - Peng, H.
AU  - Xin, S.
AU  - Pfeiffer, S.
AU  - Müller, C.
AU  - Merl-Pham, J.
AU  - Hauck, S.M.
AU  - Harter, P.N.*
AU  - Spitzer, D.*
AU  - Devraj, K.*
AU  - Varynskyi, B.
AU  - Arzberger, T.*
AU  - Momma, S.*
AU  - Schick, J.A.
C1  - 70569
C2  - 55767
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - Fatty acid-binding protein 5 is a functional biomarker and indicator of ferroptosis in cerebral hypoxia.
JO  - Cell Death Dis.
VL  - 15
IS  - 4
PB  - Springernature
PY  - 2024
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Ferroptosis is a regulated and non-apoptotic form of cell death mediated by iron-dependent peroxidation of polyunsaturated fatty acyl tails in phospholipids. Research of the past years has shed light on the occurrence of ferroptosis in organ injury and degenerative diseases of the brain, kidney, heart, and other tissues. Hence, ferroptosis inhibition may prove therapeutically beneficial to treat distinct diseases. In this study, we explored the ferroptosis-modulating activity of seratrodast, an inhibitor of thromboxane A2 (TXA2) receptor, which is approved in some countries for the treatment of asthma. Interestingly, seratrodast suppressed ferroptosis, but not apoptosis and necroptosis; thus, demonstrating selective anti-ferroptotic activity. While seratrodast itself does not inhibit lipid peroxidation, it exhibits potent radical-trapping antioxidant activity upon reduction to its corresponding hydroquinone form-analogously to ubiquinone and vitamin K. Importantly, seratrodast ameliorated the severity of renal ischemia-reperfusion injury in mice. Together, this study provides a drug repurposing case, where seratrodast-a marketed drug-can undergo fast-forward preclinical/clinical development for the inhibition of ferroptosis in distinct degenerative diseases.
AU  - Tschuck, J.
AU  - Tonnus, W.*
AU  - Gavali, S.*
AU  - Kolak, A.
AU  - Mallais, M.*
AU  - Maremonti, F.*
AU  - Sato, M.*
AU  - Rothenaigner, I.
AU  - Friedmann Angeli, J.P.*
AU  - Pratt, D.A.*
AU  - Linkermann, A.*
AU  - Hadian, K.
C1  - 72492
C2  - 56632
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - Seratrodast inhibits ferroptosis by suppressing lipid peroxidation.
JO  - Cell Death Dis.
VL  - 15
IS  - 11
PB  - Springernature
PY  - 2024
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - The original version of this article contained an error in the funding section. The correct funding should read: “This work was supported by Fondazione Italiana Sclerosi Multipla (FISM project # 1946 to AU and F. Benfenati), Compagnia di San Paolo Torino (no. 34760 to F. Benfenati), Ministero Istruzione, Università e Ricerca (PRIN-2017A9MK4R to F. Benfenati), Ministero della Salute (Ricerca Corrente to FB; Ricerca Finalizzata Giovani Ricercatori GR-2019-12370176 to AR)”. The authors apologize for the error. The original article has been corrected.
AU  - Buffolo, F.*
AU  - Petrosino, V.*
AU  - Albini, M.*
AU  - Moschetta, M.*
AU  - Carlini, F.*
AU  - Floss, T.
AU  - Kerlero de Rosbo, N.*
AU  - Cesca, F.*
AU  - Rocchi, A.*
AU  - Uccelli, A.*
AU  - Benfenati, F.*
C1  - 67761
C2  - 54239
TI  - Correction: Neuroinflammation induces synaptic scaling through IL-1β-mediated activation of the transcriptional repressor REST/NRSF.
JO  - Cell Death Dis.
VL  - 14
IS  - 5
PY  - 2023
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - The human liver has a remarkable capacity to regenerate and thus compensate over decades for fibrosis caused by toxic chemicals, drugs, alcohol, or malnutrition. To date, no protective mechanisms have been identified that help the liver tolerate these repeated injuries. In this study, we revealed dysregulation of lipid metabolism and mild inflammation as protective mechanisms by studying longitudinal multi-omic measurements of liver fibrosis induced by repeated CCl4 injections in mice (n = 45). Based on comprehensive proteomics, transcriptomics, blood- and tissue-level profiling, we uncovered three phases of early disease development-initiation, progression, and tolerance. Using novel multi-omic network analysis, we identified multi-level mechanisms that are significantly dysregulated in the injury-tolerant response. Public data analysis shows that these profiles are altered in human liver diseases, including fibrosis and early cirrhosis stages. Our findings mark the beginning of the tolerance phase as the critical switching point in liver response to repetitive toxic doses. After fostering extracellular matrix accumulation as an acute response, we observe a deposition of tiny lipid droplets in hepatocytes only in the Tolerant phase. Our comprehensive study shows that lipid metabolism and mild inflammation may serve as biomarkers and are putative functional requirements to resist further disease progression.
AU  - Hammad, S.*
AU  - Ogris, C.
AU  - Othman, A.*
AU  - Erdoesi, P.*
AU  - Schmidt-Heck, W.*
AU  - Biermayer, I.*
AU  - Helm, B.*
AU  - Gao, Y.*
AU  - Piorońska, W.*
AU  - Holland, C.H.*
AU  - D'Alessandro, L.A.*
AU  - De La Torre, C.*
AU  - Sticht, C.*
AU  - Al Aoua, S.*
AU  - Theis, F.J.
AU  - Bantel, H.*
AU  - Ebert, M.P.*
AU  - Klingmüller, U.*
AU  - Hengstler, J.G.*
AU  - Dooley, S.*
AU  - Müller, N.S.
C1  - 68112
C2  - 54590
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - Tolerance of repeated toxic injuries of murine livers is associated with steatosis and inflammation.
JO  - Cell Death Dis.
VL  - 14
IS  - 7
PB  - Springernature
PY  - 2023
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Ca2+-activated K+ channels of intermediate conductance (IK) are frequently overexpressed in breast cancer (BC) cells, while IK channel depletion reduces BC cell proliferation and tumorigenesis. This raises the question, of whether and mechanistically how IK activity interferes with the metabolic activity and energy consumption rates, which are fundamental for rapidly growing cells. Using BC cells obtained from MMTV-PyMT tumor-bearing mice, we show that both, glycolysis and mitochondrial ATP-production are reduced in cells derived from IK-deficient breast tumors. Loss of IK altered the sub-/cellular K+- and Ca2+- homeostasis and mitochondrial membrane potential, ultimately resulting in reduced ATP-production and metabolic activity. Consequently, we find that BC cells lacking IK upregulate AMP-activated protein kinase activity to induce autophagy compensating the glycolytic and mitochondrial energy shortage. Our results emphasize that IK by modulating cellular Ca2+- and K+-dynamics contributes to the remodeling of metabolic pathways in cancer. Thus, targeting IK channel might disturb the metabolic activity of BC cells and reduce malignancy.
AU  - Gross, D.J.*
AU  - Bischof, H.*
AU  - Maier, S.*
AU  - Sporbeck, K.*
AU  - Birkenfeld, A.L.
AU  - Malli, R.*
AU  - Ruth, P.*
AU  - Proikas-Cezanne, T.*
AU  - Lukowski, R.*
C1  - 66537
C2  - 53207
TI  - IKCa channels control breast cancer metabolism including AMPK-driven autophagy.
JO  - Cell Death Dis.
VL  - 13
IS  - 10
PY  - 2022
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - The danger signal extracellular calcium is pathophysiologically increased in the synovial fluid of patients with rheumatoid arthritis (RA). Calcium activates the NLRP3-inflammasome via the calcium-sensing receptor in monocytes/macrophages primed by lipopolysaccharide, and this effect is mediated by the uptake of calciprotein particles (CPPs) formed out of calcium, phosphate, and fetuin-A. Aim of the study was to unravel the influence of calcium on monocytes when the priming signal is not present. Monocytes were isolated from the blood of healthy controls and RA patients. Macrophages were characterized using scRNA-seq, DNA microarray, and proteomics. Imaging flow cytometry was utilized to study intracellular events. Here we show that extracellular calcium and CPPs lead to the differentiation of monocytes into calcium-macrophages when the priming signal is absent. Additional growth factors are not needed, and differentiation is triggered by calcium-dependent CPP-uptake, lysosomal alkalization due to CPP overload, and TFEB- and STAT3-dependent increased transcription of the lysosomal gene network. Calcium-macrophages have a needle-like shape, are characterized by excessive, constitutive SPP1/osteopontin production and a strong pro-inflammatory cytokine response. Calcium-macrophages differentiated out of RA monocytes show a stronger manifestation of this phenotype, suggesting the differentiation process might lead to the pro-inflammatory macrophage response seen in the RA synovial membrane.
AU  - Murthy, S.*
AU  - Karkossa, I.*
AU  - Schmidt, C.*
AU  - Hoffmann, A.
AU  - Hagemann, T.
AU  - Rothe, K.*
AU  - Seifert, O.*
AU  - Anderegg, U.*
AU  - von Bergen, M.*
AU  - Schubert, K.*
AU  - Rossol, M.*
C1  - 64073
C2  - 52073
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - Danger signal extracellular calcium initiates differentiation of monocytes into SPP1/osteopontin-producing macrophages.
JO  - Cell Death Dis.
VL  - 13
IS  - 1
PB  - Springernature
PY  - 2022
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - The hyperoxia-induced pro-inflammatory response and tissue damage constitute pivotal steps leading to bronchopulmonary dysplasia (BPD) in the immature lung. The pro-inflammatory cytokines are considered attractive candidates for a directed intervention but the complex interplay between inflammatory and developmental signaling pathways requires a comprehensive evaluation before introduction into clinical trials as studied here for the death inducing ligand TRAIL. At birth and during prolonged exposure to oxygen and mechanical ventilation, levels of TRAIL were lower in tracheal aspirates of preterm infants <29 weeks of gestation which developed moderate/severe BPD. These findings were reproduced in the newborn mouse model of hyperoxic injury. The loss of TRAIL was associated with increased inflammation, apoptosis induction and more pronounced lung structural simplification after hyperoxia exposure for 7 days while activation of NFκB signaling during exposure to hyperoxia was abrogated. Pretreatment with recombinant TRAIL rescued the developmental distortions in precision cut lung slices of both wildtype and TRAIL−/− mice exposed to hyperoxia. Of importance, TRAIL preserved alveolar type II cells, mesenchymal progenitor cells and vascular endothelial cells. In the situation of TRAIL depletion, our data ascribe oxygen toxicity a more injurious impact on structural lung development. These data are not surprising taking into account the diverse functions of TRAIL and its stimulatory effects on NFκB signaling as central driver of survival and development. TRAIL exerts a protective role in the immature lung as observed for the death inducing ligand TNF-α before.
AU  - Shahzad, T.*
AU  - Chao, C.M.*
AU  - Hadzic, S.*
AU  - Behnke, J.*
AU  - Biebach, L.*
AU  - Boettcher-Friebertshaeuser, E.*
AU  - Wilhelm, J.*
AU  - Hilgendorff, A.
AU  - Zimmer, K.*
AU  - Morty, R.E.*
AU  - Bellusci, S.*
AU  - Ehrhardt, H.*
C1  - 65702
C2  - 52463
TI  - TRAIL protects the immature lung from hyperoxic injury.
JO  - Cell Death Dis.
VL  - 13
IS  - 7
PY  - 2022
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - The cytosolic protein rubicon (RUBCN) has been implicated in the removal of necrotic debris and autoimmunity. However, the role of RUBCN in models of acute kidney injury (AKI), a condition that typically involves necrotic kidney tubules, was not investigated. Here, we demonstrate that RUBCN-deficient mice are hypersensitive to renal damage induced by ischemia-reperfusion injury (IRI) and cisplatin-induced AKI. Combined deficiency of RUBCN and mixed lineage kinase domain-like (MLKL) partially reversed the sensitivity in the IRI model suggesting that the absence of RUBCN sensitizes to necroptosis in that model. Necroptosis is known to contribute to TNFα-induced severe inflammatory response syndrome (SIRS), but we detected no statistically significant difference in overall survival following injection of TNFα in RUBCN-deficient mice. We additionally generated RUBCN-deficient mice which lack gasdermin D (GSDMD), the terminal mediator of pyroptosis, but no reversal of the AKI phenotype was observed. Finally, and in contrast to the previous understanding of the role of RUBCN, we did not find a significant autoimmune phenotype in RUBCN-deficient mice, but detected chronic kidney injury (CKD) in aged RUBCN-deficient mice of both sexes. In summary, our data indicate that RUBCN-deficient mice are hypersensitive to kidney injury.
AU  - Tonnus, W.*
AU  - Locke, S.*
AU  - Meyer, C.*
AU  - Maremonti, F.*
AU  - Eggert, L.*
AU  - von Mässenhausen, A.*
AU  - Bornstein, S.R.
AU  - Green, D.R.*
AU  - Linkermann, A.*
C1  - 64609
C2  - 52343
TI  - Rubicon-deficiency sensitizes mice to mixed lineage kinase domain-like (MLKL)-mediated kidney ischemia-reperfusion injury.
JO  - Cell Death Dis.
VL  - 13
IS  - 3
PY  - 2022
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Signaling pathways of regulated necrosis, such as necroptosis and ferroptosis, contribute to acute kidney injury (AKI), but the role of pyroptosis is unclear. Pyroptosis is mediated by the pore-forming protein gasdermin D (GSDMD). Here, we report a specific pattern of GSDMD-protein expression in the peritubular compartment of mice that underwent bilateral ischemia and reperfusion injury (IRI). Along similar lines, the GSDMD-protein expression in whole kidney lysates increased during the first 84 h following cisplatin-induced AKI. Importantly, unlike whole kidney lysates, no GSDMD-protein expression was detectable in isolated kidney tubules. In IRI and cisplatin-induced AKI, GSDMD-deficient mice exhibited hypersensitivity to injury as assessed by tubular damage, elevated markers of serum urea, and serum creatinine. This hypersensitivity was reversed by a combined deficiency of GSDMD and the necroptosis mediator mixed lineage kinase domain-like (MLKL). In conclusion, we demonstrate a non-cell autonomous role for GSDMD in protecting the tubular compartment from necroptosis-mediated damage in IRI.
AU  - Tonnus, W.*
AU  - Maremonti, F.*
AU  - Belavgeni, A.*
AU  - Latk, M.*
AU  - Brucker, A.J.*
AU  - von Maessenhausen, A.*
AU  - Meyer, C.*
AU  - Locke, S.*
AU  - Gembardt, F.*
AU  - Beer, K.*
AU  - Hoppenz, P.*
AU  - Hugo, C.*
AU  - Anders, H.J.*
AU  - Bornstein, S.R.
AU  - Shao, F.W.*
AU  - Linkermann, A.*
C1  - 66219
C2  - 52865
TI  - Gasdermin D-deficient mice are hypersensitive to acute kidney injury.
JO  - Cell Death Dis.
VL  - 13
IS  - 9
PY  - 2022
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Basal-like breast cancer (BLBC) is a highly aggressive breast cancer subtype frequently associated with poor prognosis. Due to the scarcity of targeted treatment options, conventional cytotoxic chemotherapies frequently remain the standard of care. Unfortunately, their efficacy is limited as BLBC malignancies rapidly develop resistant phenotypes. Using transcriptomic and proteomic approaches in human and murine BLBC cells, we aimed to elucidate the molecular mechanisms underlying the acquisition of aggressive and chemotherapy-resistant phenotypes in these mammary tumors. Specifically, we identified and characterized a novel short isoform of Roundabout Guidance Receptor 3 (ROBO3s), upregulated in BLBC in response to chemotherapy and encoding for a protein variant lacking the transmembrane domain. We established an important role for the ROBO3s isoform, mediating cancer stem cell properties by stimulating the Hippo-YAP signaling pathway, and thus driving resistance of BLBC cells to cytotoxic drugs. By uncovering the conservation of ROBO3s expression across multiple cancer types, as well as its association with reduced BLBC-patient survival, we emphasize its potential as a prognostic marker and identify a novel attractive target for anti-cancer drug development.
AU  - Werner, M.
AU  - Dyas, A.*
AU  - Parfentev, I.*
AU  - Schmidt, G.E.*
AU  - Mieczkowska, I.K.*
AU  - Mueller-Kirschbaum, L.C.*
AU  - Müller, C.*
AU  - Kalkhof, S.*
AU  - Reinhardt, O.*
AU  - Urlaub, H.*
AU  - Alves, F.*
AU  - Gallwas, J.*
AU  - Prokakis, E.*
AU  - Wegwitz, F.*
C1  - 66085
C2  - 52641
TI  - ROBO3s: A novel ROBO3 short isoform promoting breast cancer aggressiveness.
JO  - Cell Death Dis.
VL  - 13
IS  - 9
PY  - 2022
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Neuroinflammation is associated with synapse dysfunction and cognitive decline in patients and animal models. One candidate for translating the inflammatory stress into structural and functional changes in neural networks is the transcriptional repressor RE1-silencing transcription factor (REST) that regulates the expression of a wide cluster of neuron-specific genes during neurogenesis and in mature neurons. To study the cellular and molecular pathways activated under inflammatory conditions mimicking the experimental autoimmune encephalomyelitis (EAE) environment, we analyzed REST activity in neuroblastoma cells and mouse cortical neurons treated with activated T cell or microglia supernatant and distinct pro-inflammatory cytokines. We found that REST is activated by a variety of neuroinflammatory stimuli in both neuroblastoma cells and primary neurons, indicating that a vast transcriptional change is triggered during neuroinflammation. While a dual activation of REST and its dominant-negative splicing isoform REST4 was observed in N2a neuroblastoma cells, primary neurons responded with a pure full-length REST upregulation in the absence of changes in REST4 expression. In both cases, REST upregulation was associated with activation of Wnt signaling and increased nuclear translocation of β-catenin, a well-known intracellular transduction pathway in neuroinflammation. Among single cytokines, IL-1β caused a potent and prompt increase in REST transcription and translation in neurons, which promoted a delayed and strong synaptic downscaling specific for excitatory synapses, with decreased frequency and amplitude of spontaneous synaptic currents, decreased density of excitatory synaptic connections, and decreased frequency of action potential-evoked Ca2+ transients. Most important, the IL-1β effects on excitatory transmission were strictly REST dependent, as conditional deletion of REST completely occluded the effects of IL-1β activation on synaptic transmission and network excitability. Our results demonstrate that REST upregulation represents a new pathogenic mechanism for the synaptic dysfunctions observed under neuroinflammatory conditions and identify the REST pathway as therapeutic target for EAE and, potentially, for multiple sclerosis.
AU  - Buffolo, F.*
AU  - Petrosino, V.*
AU  - Albini, M.*
AU  - Moschetta, M.*
AU  - Carlini, F.*
AU  - Floss, T.
AU  - Kerlero de Rosbo, N.*
AU  - Cesca, F.*
AU  - Rocchi, A.*
AU  - Uccelli, A.*
AU  - Benfenati, F.*
C1  - 61505
C2  - 50322
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - Neuroinflammation induces synaptic scaling through IL-1β-mediated activation of the transcriptional repressor REST/NRSF.
JO  - Cell Death Dis.
VL  - 12
IS  - 2
PB  - Springernature
PY  - 2021
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Bone marrow-derived human mesenchymal stem cells (hMSCs) are recruited to damaged or inflamed tissues where they contribute to tissue repair. This multi-step process involves chemokine-directed invasion of hMSCs and on-site release of factors that influence target cells or tumor tissues. However, the underlying molecular mechanisms are largely unclear. Previously, we described that microRNA let-7f controls hMSC differentiation. Here, we investigated the role of let-7f in chemotactic invasion and paracrine anti-tumor effects. Incubation with stromal cell-derived factor-1α (SDF-1α) or inflammatory cytokines upregulated let-7f expression in hMSCs. Transfection of hMSCs with let-7f mimics enhanced CXCR4-dependent invasion by augmentation of pericellular proteolysis and release of matrix metalloproteinase-9. Hypoxia-induced stabilization of the hypoxia-inducible factor 1 alpha in hMSCs promoted cell invasion via let-7f and activation of autophagy. Dependent on its endogenous level, let-7f facilitated hMSC motility and invasion through regulation of the autophagic flux in these cells. In addition, secreted let-7f encapsulated in exosomes was increased upon upregulation of endogenous let-7f by treatment of the cells with SDF-1α, hypoxia, or induction of autophagy. In recipient 4T1 tumor cells, hMSC-derived exosomal let-7f attenuated proliferation and invasion. Moreover, implantation of 3D spheroids composed of hMSCs and 4T1 cells into a breast cancer mouse model demonstrated that hMSCs overexpressing let-7f inhibited tumor growth in vivo. Our findings provide evidence that let-7f is pivotal in the regulation of hMSC invasion in response to inflammation and hypoxia, suggesting that exosomal let-7f exhibits paracrine anti-tumor effects.
AU  - Egea, V.*
AU  - Kessenbrock, K.*
AU  - Lawson, D.*
AU  - Bartelt, A.
AU  - Weber, C.*
AU  - Ries, C.*
C1  - 62088
C2  - 50642
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - Let-7f miRNA regulates SDF-1α- and hypoxia-promoted migration of mesenchymal stem cells and attenuates mammary tumor growth upon exosomal release.
JO  - Cell Death Dis.
VL  - 12
IS  - 6
PB  - Springernature
PY  - 2021
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Glioblastoma (GBM), the most malignant tumor of the central nervous system, is marked by its dynamic response to microenvironmental niches. In particular, this cellular plasticity contributes to the development of an immediate resistance during tumor treatment. Novel insights into the developmental trajectory exhibited by GBM show a strong capability to respond to its microenvironment by clonal selection of specific phenotypes. Using the same mechanisms, malignant GBM do develop intrinsic mechanisms to resist chemotherapeutic treatments. This resistance was reported to be sustained by the paracrine and autocrine glutamate signaling via ionotropic and metabotropic receptors. However, the extent to which glutamatergic signaling modulates the chemoresistance and transcriptional profile of the GBM remains unexplored. In this study we aimed to map the manifold effects of glutamate signaling in GBM as the basis to further discover the regulatory role and interactions of specific receptors, within the GBM microenvironment. Our work provides insights into glutamate release dynamics, representing its importance for GBM growth, viability, and migration. Based on newly published multi-omic datasets, we explored the and characterized the functions of different ionotropic and metabotropic glutamate receptors, of which the metabotropic receptor 3 (GRM3) is highlighted through its modulatory role in maintaining the ability of GBM cells to evade standard alkylating chemotherapeutics. We addressed the clinical relevance of GRM3 receptor expression in GBM and provide a proof of concept where we manipulate intrinsic mechanisms of chemoresistance, driving GBM towards chemo-sensitization through GRM3 receptor inhibition. Finally, we validated our findings in our novel human organotypic section-based tumor model, where GBM growth and proliferation was significantly reduced when GRM3 inhibition was combined with temozolomide application. Our findings present a new picture of how glutamate signaling via mGluR3 interacts with the phenotypical GBM transcriptional programs in light of recently published GBM cell-state discoveries.
AU  - Maier, J.P.*
AU  - Kueckelhaus, J.*
AU  - Behringer, S.P.*
AU  - Garrelfs, N.*
AU  - Will, P.*
AU  - Sun, N.
AU  - von Ehr, J.*
AU  - Goeldner, J.M.*
AU  - Pfeifer, D.*
AU  - Follo, M.*
AU  - Hannibal, L.*
AU  - Walch, A.K.
AU  - Hofmann, U.G.*
AU  - Beck, J.*
AU  - Heiland, D.H.*
AU  - Schnell, O.*
C1  - 62644
C2  - 51016
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - Inhibition of metabotropic glutamate receptor III facilitates sensitization to alkylating chemotherapeutics in glioblastoma.
JO  - Cell Death Dis.
VL  - 12
IS  - 8
PB  - Springernature
PY  - 2021
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Resistance against radio(chemo)therapy-induced cell death is a major determinant of oncological treatment failure and remains a perpetual clinical challenge. The underlying mechanisms are manifold and demand for comprehensive, cancer entity- and subtype-specific examination. In the present study, resistance against radiotherapy was systematically assessed in a panel of human head-and-neck squamous cell carcinoma (HNSCC) cell lines and xenotransplants derived thereof with the overarching aim to extract master regulators and potential candidates for mechanism-based pharmacological targeting. Clonogenic survival data were integrated with molecular and functional data on DNA damage repair and different cell fate decisions. A positive correlation between radioresistance and early induction of HNSCC cell senescence accompanied by NF-kappa B-dependent production of distinct senescence-associated cytokines, particularly ligands of the CXCR2 chemokine receptor, was identified. Time-lapse microscopy and medium transfer experiments disclosed the non-cell autonomous, paracrine nature of these mechanisms, and pharmacological interference with senescence-associated cytokine production by the NF-kappa B inhibitor metformin significantly improved radiotherapeutic performance in vitro and in vivo. With regard to clinical relevance, retrospective analyses of TCGA HNSCC data and an in-house HNSCC cohort revealed that elevated expression of CXCR2 and/or its ligands are associated with impaired treatment outcome. Collectively, our study identifies radiation-induced tumor cell senescence and the NF-kappa B-dependent production of distinct senescence-associated cytokines as critical drivers of radioresistance in HNSCC whose therapeutic targeting in the context of multi-modality treatment approaches should be further examined and may be of particular interest for the subgroup of patients with elevated expression of the CXCR2/ligand axis.
AU  - Schoetz, U.*
AU  - Klein, D.*
AU  - Hess J.
AU  - Shnayien, S.*
AU  - Spoerl, S.*
AU  - Orth, M.*
AU  - Mutlu, S.*
AU  - Hennel, R.*
AU  - Sieber, A.*
AU  - Ganswindt, U.*
AU  - Luka, B.*
AU  - Thomsen, A.R.*
AU  - Unger, K.
AU  - Jendrossek, V.*
AU  - Zitzelsberger, H.
AU  - Bluethgen, N.*
AU  - Belka, C.
AU  - Unkel, S.*
AU  - Klinger, B.*
AU  - Lauber, K.
C1  - 63848
C2  - 51596
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - Early senescence and production of senescence-associated cytokines are major determinants of radioresistance in head-and-neck squamous cell carcinoma.
JO  - Cell Death Dis.
VL  - 12
IS  - 12
PB  - Springernature
PY  - 2021
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Ferroptosis is a form of regulated cell death that emerges to be relevant for therapy-resistant and dedifferentiating cancers. Although several lines of evidence suggest that ferroptosis is a type of autophagy-dependent cell death, the underlying molecular mechanisms remain unclear. Fin56, a type 3 ferroptosis inducer, triggers ferroptosis by promoting glutathione peroxidase 4 (GPX4) protein degradation via a not fully understood pathway. Here, we determined that Fin56 induces ferroptosis and autophagy in bladder cancer cells and that Fin56-triggered ferroptosis mechanistically depends on the autophagic machinery. Furthermore, we found that autophagy inhibition at different stages attenuates Fin56-induced oxidative stress and GPX4 degradation. Moreover, we investigated the effects of Fin56 in combination with Torin 2, a potent mTOR inhibitor used to activate autophagy, on cell viability. We found that Fin56 synergizes with Torin 2 in cytotoxicity against bladder cancer cells. Collectively, our findings not only support the concept that ferroptosis is a type of autophagy-dependent cell death but imply that the combined application of ferroptosis inducers and mTOR inhibitors is a promising approach to improve therapeutic options in the treatment of bladder cancer.
AU  - Sun, Y.*
AU  - Berleth, N.*
AU  - Wu, W.*
AU  - Schlütermann, D.*
AU  - Deitersen, J.*
AU  - Stuhldreier, F.*
AU  - Berning, L.*
AU  - Friedrich, A.*
AU  - Akgün, S.*
AU  - Mendiburo, M.J.*
AU  - Wesselborg, S.*
AU  - Conrad, M.
AU  - Berndt, C.*
AU  - Stork, B.*
C1  - 63434
C2  - 51533
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - Fin56-induced ferroptosis is supported by autophagy-mediated GPX4 degradation and functions synergistically with mTOR inhibition to kill bladder cancer cells.
JO  - Cell Death Dis.
VL  - 12
IS  - 11
PB  - Springernature
PY  - 2021
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Sorafenib, a protein kinase inhibitor approved for the treatment of hepatocellular carcinoma and advanced renal cell carcinoma, has been repeatedly reported to induce ferroptosis by possibly involving inhibition of the cystine/glutamate antiporter, known as system xc-. Using a combination of well-defined genetically engineered tumor cell lines and canonical small molecule ferroptosis inhibitors, we now provide unequivocal evidence that sorafenib does not induce ferroptosis in a series of tumor cell lines unlike the cognate system xc- inhibitors sulfasalazine and erastin. We further show that only a subset of tumor cells dies by ferroptosis upon sulfasalazine and erastin treatment, implying that certain cell lines appear to be resistant to system xc- inhibition, while others undergo ferroptosis-independent cell death. From these findings, we conclude that sorafenib does not qualify as a bona fide ferroptosis inducer and that ferroptosis induced by system xc- inhibitors can only be achieved in a fraction of tumor cell lines despite robust expression of SLC7A11, the substrate-specific subunit of system xc-.
AU  - Zheng, J.
AU  - Sato, M.*
AU  - Mishima, E.
AU  - Sato, H.*
AU  - Proneth, B.
AU  - Conrad, M.
C1  - 62580
C2  - 50956
CY  - Campus, 4 Crinan St, London, N1 9xw, England
TI  - Sorafenib fails to trigger ferroptosis across a wide range of cancer cell lines.
JO  - Cell Death Dis.
VL  - 12
IS  - 7
PB  - Springernature
PY  - 2021
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Aggregation of alpha-synuclein (αSyn) is a crucial event underlying the pathophysiology of synucleinopathies. The existence of various intracellular and extracellular αSyn species, including cleaved αSyn, complicates the quest for an appropriate therapeutic target. Hence, to develop efficient disease-modifying strategies, it is fundamental to achieve a deeper understanding of the relevant spreading and toxic αSyn species. Here, we describe comparative and proof-of-principle approaches to determine the involvement of αSyn fragments in intercellular spreading. We demonstrate that two different αSyn fragments (1–95 and 61–140) fulfill the criteria of spreading species. They efficiently instigate formation of proteinase-K-resistant aggregates from cell-endogenous full-length αSyn, and drive it into different aggregation pathways. The resulting aggregates induce cellular toxicity. Strikingly, these aggregates are only detectable by specific antibodies. Our results suggest that αSyn fragments might be relevant not only for spreading, but also for aggregation-fate determination and differential strain formation.
AU  - Chakroun, T.*
AU  - Evsyukov, V.*
AU  - Nykänen, N.P.*
AU  - Höllerhage, M.*
AU  - Schmidt, A.*
AU  - Kamp, F.*
AU  - Ruf, V.C.*
AU  - Wurst, W.
AU  - Rösler, T.W.*
AU  - Höglinger, G.U.*
C1  - 58794
C2  - 48330
TI  - Alpha-synuclein fragments trigger distinct aggregation pathways.
JO  - Cell Death Dis.
VL  - 11
IS  - 2
PY  - 2020
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Conditions of impaired adrenal function and tissue destruction, such as in Addison's disease, and treatment resistance of adrenocortical carcinoma (ACC) necessitate improved understanding of the pathophysiology of adrenal cell death. Due to relevant oxidative processes in the adrenal cortex, our study investigated the role of ferroptosis, an iron-dependent cell death mechanism and found high adrenocortical expression of glutathione peroxidase 4 (GPX4) and long-chain-fatty-acid CoA ligase 4 (ACSL4) genes, key factors in the initiation of ferroptosis. By applying MALDI mass spectrometry imaging to normal and neoplastic adrenocortical tissue, we detected high abundance of arachidonic and adrenic acid, two long chain polyunsaturated fatty acids which undergo peroxidation during ferroptosis. In three available adrenal cortex cell models (H295R, CU-ACC1 and CU-ACC-2) a high susceptibility to GPX4 inhibition with RSL3 was documented with EC50 values of 5.7 x 10(-8), 8.1 x 10(-7) and 2.1 x 10(-8) M, respectively, while all non-steroidogenic cells were significantly less sensitive. Complete block of GPX4 activity by RSL3 led to ferroptosis which was completely reversed in adrenal cortex cells by inhibition of steroidogenesis with ketoconazole but not by blocking the final step of cortisol synthesis with metyrapone. Mitotane, the only approved drug for ACC did not induce ferroptosis, despite strong induction of lipid peroxidation in ACC cells. Together, this report is the first to demonstrate extraordinary sensitivity of adrenal cortex cells to ferroptosis dependent on their active steroid synthetic pathways. Mitotane does not induce this form of cell death in ACC cells.
AU  - Weigand, I.*
AU  - Schreiner, J.*
AU  - Röhrig, F.*
AU  - Sun, N.
AU  - Landwehr, L.S.*
AU  - Urlaub, H.*
AU  - Kendl, S.*
AU  - Kiseljak-Vassiliades, K.*
AU  - Wierman, M.E.*
AU  - Angeli, J.P.F.*
AU  - Walch, A.K.
AU  - Sbiera, S.*
AU  - Fassnacht, M.*
AU  - Kroiss, M.*
C1  - 58708
C2  - 48353
CY  - Macmillan Building, 4 Crinan St, London N1 9xw, England
TI  - Active steroid hormone synthesis renders adrenocortical cells highly susceptible to type II ferroptosis induction.
JO  - Cell Death Dis.
VL  - 11
IS  - 3
PB  - Nature Publishing Group
PY  - 2020
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - The serine-threonine kinase homeodomain-interacting protein kinase 2 (HIPK2) modulates important cellular functions during development, acting as a signal integrator of a wide variety of stress signals, and as a regulator of transcription factors and cofactors. We have previously demonstrated that HIPK2 binds and phosphorylates High-Mobility Group A1 (HMGA1), an architectural chromatinic protein ubiquitously expressed in embryonic tissues, decreasing its binding affinity to DNA. To better define the functional role of HIPK2 and HMGA1 interaction in vivo, we generated mice in which both genes are disrupted. About 50% of these Hmga1/Hipk2 double knock-out (DKO) mice die within 12 h of life (P1) for respiratory failure. The DKO mice present an altered lung morphology, likely owing to a drastic reduction in the expression of surfactant proteins, that are required for lung development. Consistently, we report that both HMGA1 and HIPK2 proteins positively regulate the transcriptional activity of the genes encoding the surfactant proteins. Moreover, these mice display an altered expression of thyroid differentiation markers, reasonably because of a drastic reduction in the expression of the thyroid-specific transcription factors PAX8 and FOXE1, which we demonstrate here to be positively regulated by HMGA1 and HIPK2. Therefore, these data indicate a critical role of HIPK2/HMGA1 cooperation in lung and thyroid development and function, suggesting the potential involvement of their impairment in the pathogenesis of human lung and thyroid diseases.
AU  - Gerlini, R.
AU  - Amendola, E.*
AU  - Conte, A.*
AU  - Valente, V.*
AU  - Tornincasa, M.*
AU  - Credendino, S.C.*
AU  - Cammarota, F.*
AU  - Gentile, C.*
AU  - Di Guida, L.*
AU  - Paladino, S.*
AU  - De Vita, G.*
AU  - Pierantoni, G.M.*
AU  - Fusco, A.*
C1  - 57116
C2  - 47540
TI  - Double knock-out of Hmga1 and Hipk2 genes causes perinatal death associated to respiratory distress and thyroid abnormalities in mice.
JO  - Cell Death Dis.
VL  - 10
IS  - 10
PY  - 2019
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Accumulation of pathological alpha-synuclein aggregates plays a major role in Parkinson's disease. Macroautophagy is a mechanism to degrade intracellular protein aggregates by wrapping them into autophagosomes, followed by fusion with lysosomes. We had previously shown that pharmacological activation of macroautophagy protects against alpha-synuclein-induced toxicity in human neurons. Here, we hypothesized that inhibition of macroautophagy would aggravate alpha-synuclein-induced cell death.Unexpectedly, inhibition of autophagosome formation by silencing of ATG5 protected from alpha-synuclein-induced toxicity. Therefore, we studied alternative cellular mechanisms to compensate for the loss of macroautophagy. ATG5 silencing did not affect the ubiquitin-proteasome system, chaperone systems, chaperone-mediated autophagy, or the unfolded protein response. However, ATG5 silencing increased the secretion of alpha-synuclein via exosomes. Blocking exosomal secretion exacerbated alpha-synuclein-induced cell death.We conclude that exosomal secretion of alpha-synuclein is increased after impaired formation of autophagosomes to reduce the intracellular alpha-synuclein burden. This compensatory mechanism prevents alpha-synuclein-induced neuronal cell death.
AU  - Fussi, N.*
AU  - Höllerhage, M.*
AU  - Chakroun, T.*
AU  - Nykänen, N.P.*
AU  - Rösler, T.W.*
AU  - Koeglsperger, T.*
AU  - Wurst, W.
AU  - Behrends, C.*
AU  - Höglinger, G.U.*
C1  - 53962
C2  - 45163
CY  - Macmillan Building, 4 Crinan St, London N1 9xw, England
TI  - Exosomal secretion of alpha-synuclein as protective mechanism after upstream blockage of macroautophagy.
JO  - Cell Death Dis.
VL  - 9
IS  - 7
PB  - Nature Publishing Group
PY  - 2018
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Colorectal cancer (CRC) is the second most common malignant neoplasia in women and men worldwide. The B-cell lymphoma 2 (Bcl-2) protein family is mainly known for its pivotal role in the regulation of the mitochondrial death pathway. Anti-apoptotic Bcl-2 proteins may provide survival benefits and induce therapy resistance in cancer cells. Among anti-apoptotic Bcl-2 proteins, we found solely Bcl-xL strongly upregulated in human CRC specimens. In order to study protein function in the context of tumor initiation and progression in vivo, we generated a mouse model lacking Bcl-xL in intestinal epithelial cells (Bcl-xL(IEC-KO)). If challenged in an inflammation-driven tumor model, Bcl-xL(IEC-KO) mice showed a significantly reduced tumor burden with lower tumor numbers per animal and decreased tumor sizes. Analysis of cell death events by immunohistochemistry and immunoblotting revealed a striking increase of apoptosis in Bcl-xL-negative tumors. qRT-PCR and immunohistochemistry excluded changes in proliferative capacity and immune cell infiltration as reasons for the reduced tumor load and thereby identify apoptosis as key mechanism. Human CRC tissue was cultured ex vivo and treated with the small molecule compound ABT-737, which inhibits Bcl-xL and Bcl-2. Under ABT-737 treatment, the amount of apoptotic tumor cells significantly increased compared with controls, whereas proliferation levels remained unaltered. In summary, our findings identify Bcl-xL as a driver in colorectal tumorigenesis and cancer progression, making it a valuable target for clinical application.
AU  - Scherr, A.L.*
AU  - Gdynia, G.*
AU  - Salou, M.*
AU  - Radhakrishnan, P.*
AU  - Duglova, K.*
AU  - Heller, A.*
AU  - Keim, S.*
AU  - Kautz, N.*
AU  - Jassowicz, A.*
AU  - Elssner, C.*
AU  - He, Y.W.*
AU  - Jaeger, D.*
AU  - Heikenwälder, M.
AU  - Schneider, M.*
AU  - Weber, A.*
AU  - Roth, W.*
AU  - Schulze-Bergkamen, H.*
AU  - Koehler, B.C.*
C1  - 49371
C2  - 41791
CY  - London
TI  - Bcl-xL is an oncogenic driver in colorectal cancer.
JO  - Cell Death Dis.
VL  - 7
IS  - 8
PB  - Nature Publishing Group
PY  - 2016
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Small-conductance Ca(2+)-activated K(+) channel activation is an emerging therapeutic approach for treatment of neurological diseases, including stroke, amyotrophic lateral sclerosis and schizophrenia. Our previous studies showed that activation of SK channels exerted neuroprotective effects through inhibition of NMDAR-mediated excitotoxicity. In this study, we tested the therapeutic potential of SK channel activation of NS309 (25 μM) in cultured human postmitotic dopaminergic neurons in vitro conditionally immortalized and differentiated from human fetal mesencephalic cells. Quantitative RT-PCR and western blotting analysis showed that differentiated dopaminergic neurons expressed low levels of SK2 channels and high levels of SK1 and SK3 channels. Further, protein analysis of subcellular fractions revealed expression of SK2 channel subtype in mitochondrial-enriched fraction. Mitochondrial complex I inhibitor rotenone (0.5 μM) disrupted the dendritic network of human dopaminergic neurons and induced neuronal death. SK channel activation reduced mitochondrial membrane potential, while it preserved the dendritic network, cell viability and ATP levels after rotenone challenge. Mitochondrial dysfunction and delayed dopaminergic cell death were prevented by increasing and/or stabilizing SK channel activity. Overall, our findings show that activation of SK channels provides protective effects in human dopaminergic neurons, likely via activation of both membrane and mitochondrial SK channels. Thus, SK channels are promising therapeutic targets for neurodegenerative disorders such as Parkinson's disease, where dopaminergic cell loss is associated with progression of the disease.
AU  - Dolga, A.M.*
AU  - de Andrade, A.*
AU  - Meissner, L.*
AU  - Knaus, H.G.*
AU  - Höllerhage, M.*
AU  - Christophersen, P.*
AU  - Zischka, H.
AU  - Plesnila, N.*
AU  - Höglinger, G.U.*
AU  - Culmsee, C.*
C1  - 29292
C2  - 33640
CY  - London
TI  - Subcellular expression and neuroprotective effects of SK channels in human dopaminergic neurons.
JO  - Cell Death Dis.
VL  - 5
PB  - Nature Publishing Group
PY  - 2014
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Death receptor-mediated apoptosis is a key mechanism for the control of immune responses and dysregulation of this pathway may lead to autoimmunity. Cellular FLICE-inhibitory proteins (c-FLIPs) are known as inhibitors of death receptor-mediated apoptosis. The only short murine c-FLIP splice variant is c-FLIPRaji (c-FLIPR). To investigate the functional role of c-FLIPR in the immune system, we used the vavFLIPR mouse model constitutively expressing murine c-FLIPR in all hematopoietic compartments. Lymphocytes from these mice are protected against CD95-mediated apoptosis and activation-induced cell death. Young vavFLIPR mice display normal lymphocyte compartments, but the lymphocyte populations alter with age. We identified reduced levels of T cells and slightly higher levels of B cells in 1-year-old vavFLIPR mice compared with wild-type (WT) littermates. Moreover, both B and T cells from aged vavFLIPR animals show activated phenotypes. Sera from 1-year-old WT and transgenic animals were analysed for anti-nuclear antibodies. Notably, elevated titres of these autoantibodies were detected in vavFLIPR sera. Furthermore, tissue damage in kidneys and lungs from aged vavFLIPR animals was observed, indicating that vavFLIPR mice develop a systemic lupus erythematosus-like phenotype with age. Taken together, these data suggest that c-FLIPR is an important modulator of apoptosis and enforced expression leads to autoimmunity.
AU  - Ewald, F.*
AU  - Annemann, M.*
AU  - Pils, M.C.*
AU  - Plaza-Sirvent, C.*
AU  - Neff, F.
AU  - Erck, C.*
AU  - Reinhold, D.*
AU  - Schmitz, I.*
C1  - 31051
C2  - 34150
CY  - London
TI  - Constitutive expression of murine c-FLIPR causes autoimmunity in aged mice.
JO  - Cell Death Dis.
VL  - 5
IS  - 4
PB  - Nature Publishing Group
PY  - 2014
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Targeting the actin cytoskeleton (CSK) of cancer cells offers a valuable strategy in cancer therapy. There are a number of natural compounds that interfere with the actin CSK, but the mode of their cytotoxic action and, moreover, their tumor-specific mechanisms are quite elusive. We used the myxobacterial compound Chondramide as a tool to first elucidate the mechanisms of cytotoxicity of actin targeting in breast cancer cells (MCF7, MDA-MB-231). Chondramide inhibits cellular actin filament dynamics shown by a fluorescence-based analysis (fluorescence recovery after photobleaching (FRAP)) and leads to apoptosis characterized by phosphatidylserine exposure, release of cytochrome C from mitochondria and finally activation of caspases. Chondramide enhances the occurrence of mitochondrial permeability transition (MPT) by affecting known MPT modulators: Hexokinase II bound to the voltage-dependent anion channel (VDAC) translocated from the outer mitochondrial membrane to the cytosol and the proapoptotic protein Bad were recruited to the mitochondria. Importantly, protein kinase C-ɛ (PKCɛ), a prosurvival kinase possessing an actin-binding site and known to regulate the hexokinase/VDAC interaction as well as Bad phosphorylation was identified as the link between actin CSK and apoptosis induction. PKCɛ, which was found overexpressed in breast cancer cells, accumulated in actin bundles induced by Chondramide and lost its activity. Our second goal was to characterize the potential tumor-specific action of actin-binding agents. As the nontumor breast epithelial cell line MCF-10A in fact shows resistance to Chondramide-induced apoptosis and notably express low level of PKCɛ, we suggest that trapping PKCɛ via Chondramide-induced actin hyperpolymerization displays tumor cell specificity. Our work provides a link between targeting the ubiquitously occurring actin CSK and selective inhibition of pro-tumorigenic PKCɛ, thus setting the stage for actin-stabilizing agents as innovative cancer drugs. This is moreover supported by the in vivo efficacy of Chondramide triggered by abrogation of PKCɛ signaling shown in a xenograft breast cancer model.
AU  - Foerster, F.*
AU  - Braig, S.*
AU  - Moser, C.*
AU  - Kubisch, R.*
AU  - Busse, J.*
AU  - Wagner, E.*
AU  - Schmoeckel, E.*
AU  - Mayr, D.*
AU  - Schmitt, S.
AU  - Huettel, S.*
AU  - Zischka, H.
AU  - Mueller, R.*
AU  - Vollmar, A.M.*
C1  - 32051
C2  - 34955
CY  - London
TI  - Targeting the actin cytoskeleton: Selective antitumor action via trapping PKCɛ.
JO  - Cell Death Dis.
VL  - 5
IS  - 8
PB  - Nature Publishing Group
PY  - 2014
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - It is commonly recognized that diabetic complications involve increased oxidative stress directly triggered by hyperglycemia. The most important cellular protective systems against such oxidative stress have yet remained unclear. Here we show that the selenoprotein thioredoxin reductase 1 (TrxR1), encoded by the Txnrd1 gene, is an essential enzyme for such protection. Individually grown Txnrd1 knockout (Txnrd1(-/-)) mouse embryonic fibroblasts (MEFs) underwent massive cell death directly linked to glucose-induced H2O2 production. This death and excessive H2O2 levels could be reverted by reconstituted expression of selenocysteine (Sec)-containing TrxR1, but not by expression of Sec-devoid variants of the enzyme. Our results show that Sec-containing TrxR1 is absolutely required for self-sufficient growth of MEFs under high-glucose conditions, owing to an essential importance of this enzyme for elimination of glucose-derived H2O2. To our knowledge, this is the first time a strict Sec-dependent function of TrxR1 has been identified as being essential for mammalian cells.
AU  - Peng, X.*
AU  - Mandal, P.K.
AU  - Kaminskyy, V.O.*
AU  - Lindqvist, A.*
AU  - Conrad, M.
AU  - Arner, E.S.J.*
C1  - 31375
C2  - 34446
CY  - London
TI  - Sec-containing TrxR1 is essential for self-sufficiency of cells by control of glucose-derived H2O2.
JO  - Cell Death Dis.
VL  - 5
PB  - Nature Publishing Group
PY  - 2014
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Resting tumor cells represent a huge challenge during anticancer therapy due to their increased treatment resistance. TNF-related apoptosis-inducing ligand (TRAIL) is a putative future anticancer drug, currently in phases I and II clinical studies. We recently showed that TRAIL is able to target leukemia stem cell surrogates. Here, we tested the ability of TRAIL to target cell cycle-arrested tumor cells. Cell cycle arrest was induced in tumor cell lines and xenografted tumor cells in G0, G1 or G2 using cytotoxic drugs, phase-specific inhibitors or RNA interference against cyclinB and E. Biochemical or molecular arrest at any point of the cell cycle increased TRAIL-induced apoptosis. Accordingly, when cell cycle arrest was disabled by addition of caffeine, the antitumor activity of TRAIL was reduced. Most important for clinical translation, tumor cells from three children with B precursor or T cell acute lymphoblastic leukemia showed increased TRAIL-induced apoptosis upon knockdown of either cyclinB or cyclinE, arresting the cell cycle in G2 or G1, respectively. Taken together and in contrast to most conventional cytotoxic drugs, TRAIL exerts enhanced antitumor activity against cell cycle-arrested tumor cells. Therefore, TRAIL might represent an interesting drug to treat static-tumor disease, for example, during minimal residual disease.
AU  - Ehrhardt, H.
AU  - Wachter, F.
AU  - Grunert, M.
AU  - Jeremias, I.
C1  - 26130
C2  - 32084
TI  - Cell cycle-arrested tumor cells exhibit increased sensitivity towards TRAIL-induced apoptosis.
JO  - Cell Death Dis.
VL  - 4
IS  - 6
PB  - Nature Publishing
PY  - 2013
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - During polychemotherapy, cytotoxic drugs are given in combinations to enhance their anti-tumor effectiveness. For most drug combinations, underlying signaling mechanisms responsible for positive drug-drug interactions remain elusive. Here, we prove a decisive role for the Bcl-2 family member NOXA to mediate cell death by certain drug combinations, even if drugs were combined which acted independently from NOXA, when given alone. In proof-of-principle studies, betulinic acid, doxorubicin and vincristine induced cell death in a p53- and NOXA-independent pathway involving mitochondrial pore formation, release of cytochrome c and caspase activation. In contrast, when betulinic acid was combined with either doxorubicine or vincristine, cell death signaling changed considerably; the drug combinations clearly depended on both p53 and NOXA. Similarly and of high clinical relevance, in patient-derived childhood acute leukemia samples the drug combinations, but not the single drugs depended on p53 and NOXA, as shown by RNA interference studies in patient-derived cells. Our data emphasize that NOXA represents an important target molecule for combinations of drugs that alone do not target NOXA. NOXA might have a special role in regulating apoptosis sensitivity in the complex interplay of polychemotherapy. Deciphering the differences in signaling of single drugs and drug combinations might enable designing highly effective novel polychemotherapy regimens. Cell Death and Disease (2012) 3, e327; doi:10.1038/cddis.2012.53; published online 21 June 2012
AU  - Ehrhardt, H.
AU  - Höfig, I.
AU  - Wachter, F.
AU  - Obexer, P.*
AU  - Fulda, S.*
AU  - Terziyska, N.
AU  - Jeremias, I.
C1  - 8195
C2  - 30018
SP  - e327
TI  - NOXA as critical mediator for drug combinations in polychemotherapy.
JO  - Cell Death Dis.
VL  - 3
IS  - 6
PB  - Nature Publishing Group
PY  - 2012
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - Besides inducing apoptosis, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) activates NF-κB. The apoptosis signaling pathway of TRAIL is well characterized involving TRAIL receptors, Fas-associated protein with death domain (FADD) and caspase-8. In contrast, the molecular mechanism of TRAIL signaling to NF-κB remains controversial. Here, we characterized the receptor-proximal mediators of NF-κB activation by TRAIL. Deletion of the DD of TRAIL receptors 1 and 2 revealed that it is essential in NF-κB signaling. Because FADD interacts with the TRAIL receptor DD, FADD was tested. RNAi-mediated knockdown of FADD or FADD deficiency in JURKAT T-cell leukemia cells decreased or disabled NF-κB signaling by TRAIL. In contrast, TRAIL-induced activation of NF-κB was maintained upon loss of receptor interacting protein 1 (RIP1) or knockdown of FLICE-like inhibitory protein (FLIP). Exogenous expression of FADD rescued TRAIL-induced NF-κB signaling. Loss-of-function mutations of FADD within the RHDLL motif of the death effector domain, which is required for TRAIL-induced apoptosis, abrogated FADD's ability to recruit caspase-8 and mediate NF-κB activation. Accordingly, deficiency of caspase-8 inhibited TRAIL-induced activation of NF-κB, which was rescued by wild-type caspase-8, but not by a catalytically inactive caspase-8 mutant. These data establish the mechanism of TRAIL-induced NF-κB activation involving the TRAIL receptor DD, FADD and caspase-8, but not RIP1 or FLIP. Our results show that signaling of TRAIL-induced apoptosis and NF-κB bifurcates downstream of caspase-8.
AU  - Grunert, M.
AU  - Gottschalk, K.
AU  - Kapahnke, J.
AU  - Gündisch, S.
AU  - Kieser, A.
AU  - Jeremias, I.
C1  - 11147
C2  - 30519
TI  - The adaptor protein FADD and the initiator caspase-8 mediate activation of NF-κB by TRAIL.
JO  - Cell Death Dis.
VL  - 3
IS  - 10
PB  - Nature Publishing Group
PY  - 2012
SN  - 2041-4889
ER  - 

TY  - JOUR
AB  - The wogonin-containing herb Scutellaria baicalensis has successfully been used for curing various diseases in traditional Chinese medicine. Wogonin has been shown to induce apoptosis in different cancer cells and to suppress growth of human cancer xenografts in vivo. However, its direct targets remain unknown. In this study, we demonstrate for the first time that wogonin and structurally related natural flavones, for example, apigenin, chrysin and luteolin, are inhibitors of cyclin-dependent kinase 9 (CDK9) and block phosphorylation of the carboxy-terminal domain of RNA polymerase II at Ser(2). This effect leads to reduced RNA synthesis and subsequently rapid downregulation of the short-lived anti-apoptotic protein myeloid cell leukemia 1 (Mcl-1) resulting in apoptosis induction in cancer cells. We show that genetic inhibition of Mcl-1 or CDK9 expression by siRNA is sufficient to mimic flavone-induced apoptosis. Pull-down and in silico docking studies demonstrate that wogonin directly binds to CDK9, presumably to the ATP-binding pocket. In contrast, wogonin does not inhibit CDK2, CDK4 and CDK6 at doses that inhibit CDK9 activity. Furthermore, we show that wogonin preferentially inhibits CDK9 in malignant compared with normal lymphocytes. Thus, our study reveals a new mechanism of anti-cancer action of natural flavones and supports CDK9 as a therapeutic target in oncology.
AU  - Polier, G.*
AU  - Ding, J.*
AU  - Konkimalla, B.V.*
AU  - Eick, D.
AU  - Ribeiro, N.*
AU  - Köhler, R.*
AU  - Giaisi, M.*
AU  - Efferth, T.*
AU  - Desaubry, L.*
AU  - Krammer, P.H.*
AU  - Li-Weber, M.*
C1  - 5783
C2  - 28943
TI  - Wogonin and related natural flavones are inhibitors of CDK9 that induce apoptosis in cancer cells by transcriptional suppression of Mcl-1.
JO  - Cell Death Dis.
VL  - 2
PB  - Nature Publ. Group
PY  - 2011
SN  - 2041-4889
ER  -