TY  - JOUR
AB  - Hox genes play key roles in the anterior-posterior (AP) specification of all 3 germ layers during different developmental stages. It is only partially understood how they function in widely different developmental contexts, particularly with regards to extracellular signaling, and to what extent their function can be harnessed to guide cell specification in vitro. Here, we addressed the role of Hoxb1 in 2 distinct developmental contexts; in mouse embryonic stem cells (mES)-derived neuromesodermal progenitors (NMPs) and hindbrain neural progenitors. We found that Hoxb1 promotes NMP survival through the upregulation of Fgf8, Fgf17, and other components of Fgf signaling as well as the repression of components of the apoptotic pathway. Additionally, it upregulates other anterior Hox genes suggesting that it plays an active role in the early steps of AP specification. In neural progenitors, Hoxb1 synergizes with shh to repress anterior and dorsal neural markers, promote the expression of ventral neural markers and direct the specification of facial branchiomotorneuron (FBM)-like progenitors. Hoxb1 and shh synergize in regulating the expression of diverse signals and signaling molecules, including the Ret tyrosine kinase receptor. Finally, Hoxb1 synergizes with exogenous Glial cell line-derived neurotrophic factor (GDNF) to strengthen Ret expression and further promote the generation of FBM-like progenitors. Facial branchiomotorneuron-like progenitors survived for at least 6 months and differentiated into postmitotic neurons after orthotopic transplantation near the facial nucleus of adult mice. These results suggested that the patterning activity of Hox genes in combination with downstream signaling molecules can be harnessed for the generation of defined neural populations and transplantations with implications for neurodegenerative diseases.
AU  - Pazur, K.
AU  - Giannios, I.
AU  - Lesche, M.*
AU  - Rodriguez-Aznar, E.
AU  - Gavalas, A.
C1  - 64506
C2  - 52243
SP  - 175-189
TI  - Hoxb1 regulates distinct signaling pathways in neuromesodermal and hindbrain progenitors to promote cell survival and specification.
JO  - Stem Cells
VL  - 40
IS  - 2
PY  - 2022
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - Wnt/β-catenin signaling regulates progenitor cell fate decisions during lung development and in various adult tissues. Ectopic activation of Wnt/β-catenin signaling promotes tissue repair in emphysema, a devastating lung disease with progressive loss of parenchymal lung tissue. The identity of Wnt/β-catenin responsive progenitor cells and the potential impact of Wnt/β-catenin signaling on adult distal lung epithelial progenitor cell function in emphysema are poorly understood. Here, we used a TCF/Lef:H2B/GFP reporter mice to investigate the role of Wnt/β-catenin signaling in lung organoid formation. We identified an organoid-forming adult distal lung epithelial progenitor cell population characterized by a low Wnt/β-catenin activity, which was enriched in club and alveolar epithelial type (AT)II cells. Endogenous Wnt/β-catenin activity was required for the initiation of multiple subtypes of distal lung organoids derived from the Wntlow epithelial progenitors. Further ectopic Wnt/β-catenin activation specifically led to an increase in alveolar organoid number; however, the subsequent proliferation of alveolar epithelial cells in the organoids did not require constitutive Wnt/β-catenin signaling. Distal lung epithelial progenitor cells derived from the mouse model of elastase-induced emphysema exhibited reduced organoid forming capacity. This was rescued by Wnt/β-catenin signal activation, which largely increased the number of alveolar organoids. Together, our study reveals a novel mechanism of lung epithelial progenitor cell activation in homeostasis and emphysema.
AU  - Hu, Y.*
AU  - Ng-Blichfeldt, J.P.
AU  - Ota, C.
AU  - Ciminieri, C.*
AU  - Ren, W.*
AU  - Hiemstra, P.S.*
AU  - Stolk, J.*
AU  - Gosens, R.*
AU  - Königshoff, M.
C1  - 59348
C2  - 48752
CY  - 111 River St, Hoboken 07030-5774, Nj Usa
SP  - 1467-1478
TI  - Wnt/β-catenin signaling is critical for regenerative potential of distal lung epithelial progenitor cells in homeostasis and emphysema.
JO  - Stem Cells
VL  - 38
IS  - 11
PB  - Wiley
PY  - 2020
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - Understanding the mechanisms that promote the specification of pancreas progenitors and regulate their self-renewal and differentiation will help to maintain and expand pancreas progenitor cells derived from human pluripotent stem (hPS) cells. This will improve the efficiency of current differentiation protocols of hPS cells into beta-cells and bring such cells closer to clinical applications for the therapy of diabetes. Aldehyde dehydrogenase 1b1 (Aldh1b1) is a mitochondrial enzyme expressed specifically in progenitor cells during mouse pancreas development, and we have shown that its functional inactivation leads to accelerated differentiation and deficient beta-cells. In this report, we aimed to identify small molecule inducers of Aldh1b1 expression taking advantage of a mouse embryonic stem (mES) cell Aldh1b1 lacZ reporter line and a pancreas differentiation protocol directing mES cells into pancreatic progenitors. We identified AMI-5, a protein methyltransferase inhibitor, as an Aldh1b1 inducer and showed that it can maintain Aldh1b1 expression in embryonic pancreas explants. This led to a selective reduction in endocrine specification. This effect was due to a downregulation of Ngn3, and it was mediated through Aldh1b1 since the effect was abolished in Aldh1b1 null pancreata. The findings implicated methyltransferase activity in the regulation of endocrine differentiation and showed that methyltransferases can act through specific regulators during pancreas differentiation.
AU  - Giannios, I.
AU  - Serafimidis, I.*
AU  - Anastasiou, V.
AU  - Pezzolla, D.*
AU  - Lesche, M.
AU  - Andree, C.*
AU  - Bickle, M.*
AU  - Gavalas, A.
C1  - 55529
C2  - 46252
CY  - 111 River St, Hoboken 07030-5774, Nj Usa
SP  - 640-651
TI  - Protein methyltransferase inhibition decreases endocrine specification through the upregulation of Aldh1b1 expression.
JO  - Stem Cells
VL  - 37
IS  - 5
PB  - Wiley
PY  - 2019
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - We asked whether cell-cycle associated protein p27kip1 might be involved in the transition of precursor cells to postmitotic maturation in adult hippocampal neurogenesis. p27kip1 was expressed throughout the dentate gyrus with a strong nuclear expression in early postmitotic, calretinin-positive neurons and neuronally determined progenitor cells (type-3 and some type-2b), lower or absent expression in radial glia-like precursor cells (type-1) and type-2a cells and essentially no expression in granule cells. This suggested a transitory role in late proliferative and early postmitotic phases of neurogenesis. Inconsistent with a role limited to cell cycle arrest the acute stimuli, voluntary wheel running (RUN), environmental enrichment (ENR) and kainate-induced seizures (KA) increased p27kip1 expressing cells. Sequential short-term combination of RUN and ENR yielded more p27kip1 cells than either stimulus alone, indicating an additive effect. In vitro, p27kip1 was lowly expressed by proliferating precursor cells but increased upon differentiation. In p27kip1-/- mice neurogenesis was reduced in vivo, whereas the number of proliferating cells was increased. Accordingly, the microdissected dentate gyrus of p27kip1-/- mice generated more colonies in the neurosphere assay and an increased number of larger spheres with the differentiation potential unchanged. In p27kip1-/- monolayer cultures, proliferation was increased and cell cycle genes were up-regulated. In the Morris water maze p27kip1-/- mice learned the task but were specifically impaired in the reversal phase explainable by the decrease in adult neurogenesis. We conclude that p27kip1 is involved in the decisive step around cell-cycle exit and plays an important role in activity-regulated and functionally relevant adult hippocampal neurogenesis.
AU  - Hörster, H.*
AU  - Garthe, A.*
AU  - Walker, T.L.*
AU  - Ichwan, M.*
AU  - Steiner, B.*
AU  - Khan, M.A.
AU  - Lie, D.C.C.*
AU  - Nicola, Z.*
AU  - Ramirez-Rodriguez, G.*
AU  - Kempermann, G.*
C1  - 49848
C2  - 40979
TI  - p27kip1 is required for functionally relevant adult hippocampal neurogenesis in mice.
JO  - Stem Cells
PY  - 2016
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - During cardiogenesis, most myocytes arise from cardiac progenitors expressing the transcription factors Isl1 and Nkx2-5. Here, we show that a direct repression of Isl1 by Nkx2-5 is necessary for proper development of the ventricular myocardial lineage. Overexpression of Nkx2-5 in mouse embryonic stem cells (ESCs) delayed specification of cardiac progenitors and inhibited expression of Isl1 and its downstream targets in Isl1+ precursors. Embryos deficient for Nkx2-5 in the Isl1+ lineage failed to downregulate Isl1 protein in cardiomyocytes of the heart tube. We demonstrated that Nkx2-5 directly binds to an Isl1 enhancer and represses Isl1 transcriptional activity. Furthermore, we showed that overexpression of Isl1 does not prevent cardiac differentiation of ESCs and in Xenopus laevis embryos. Instead, it leads to enhanced specification of cardiac progenitors, earlier cardiac differentiation, and increased cardiomyocyte number. Functional and molecular characterization of Isl1-overexpressing cardiomyocytes revealed higher beating frequencies in both ESC-derived contracting areas and Xenopus Isl1-gain-of-function hearts, which associated with upregulation of nodal-specific genes and downregulation of transcripts of working myocardium. Immunocytochemistry of cardiomyocyte lineage-specific markers demonstrated a reduction of ventricular cells and an increase of cells expressing the pacemaker channel Hcn4. Finally, optical action potential imaging of single cardiomyocytes combined with pharmacological approaches proved that Isl1 overexpression in ESCs resulted in normally electrophysiologically functional cells, highly enriched in the nodal subtype at the expense of the ventricular lineage. Our findings provide an Isl1/Nkx2-5-mediated mechanism that coordinately regulates the specification of cardiac progenitors toward the different myocardial lineages and ensures proper acquisition of myocyte subtype identity.
AU  - Dorn, T.*
AU  - Goedel, A.*
AU  - Lam, J.T.*
AU  - Haas, J.A.*
AU  - Tian, Q.*
AU  - Herrmann, F.*
AU  - Bundschu, K.*
AU  - Dobreva, G.*
AU  - Schiemann, M.
AU  - Dirschinger, R.J.*
AU  - Guo, Y.*
AU  - Kühl, S.J.*
AU  - Sinnecker, D.*
AU  - Lipp, P.*
AU  - Laugwitz, K.L.*
AU  - Kühl, M.*
AU  - Moretti, A.*
C1  - 44093
C2  - 36891
CY  - Hoboken
SP  - 1113-1129
TI  - Direct Nkx2-5 transcriptional repression of Isl1 controls cardiomyocyte subtype identity.
JO  - Stem Cells
VL  - 33
IS  - 4
PB  - Wiley-blackwell
PY  - 2015
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - The fate of neural progenitor cells (NPC) is determined by a complex interplay of intrinsic programs and extrinsic signals, very few of which are known. β-catenin transduces extracellular Wnt signals, but also maintains adherens junctions integrity. Here, we identify for the first time the contribution of β-catenin transcriptional activity as opposed to its adhesion role in the development of the cerebral cortex by combining a novel β-catenin mutant allele with conditional inactivation approaches. Wnt/β-catenin signaling ablation leads to premature NPC differentiation, but, in addition, to a change in progenitor cell cycle kinetics and an increase in basally dividing progenitors. Interestingly, Wnt/β-catenin signaling affects the sequential fate switch of progenitors, leading to a shortened neurogenic period with decreased number of both deep and upper-layer neurons and later, to precocious astrogenesis. Indeed, a genome-wide analysis highlighted the premature activation of a corticogenesis differentiation program in the Wnt/β-catenin signaling-ablated cortex. Thus, β-catenin signaling controls the expression of a set of genes that appear to act downstream of canonical Wnt signaling to regulate the stage-specific production of appropriate progenitor numbers, neuronal subpopulations, and astroglia in the forebrain.
AU  - Draganova, K.*
AU  - Zemke, M.*
AU  - Zurkirchen, L.*
AU  - Valenta, T.*
AU  - Cantù, C.*
AU  - Okoniewski, M.*
AU  - Schmid, M.-T.
AU  - Hoffmans, R.*
AU  - Götz, M.
AU  - Basler, K.*
AU  - Sommer, L.*
C1  - 42803
C2  - 35342
SP  - 170-182
TI  - Wnt/β-catenin signaling regulates sequential fate decisions of murine cortical precursor cells.
JO  - Stem Cells
VL  - 33
IS  - 1
PY  - 2015
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - The generation of induced pluripotent stem (iPS) cells has successfully been achieved in many species. However, the identification of truly reprogrammed iPS cells still remains laborious and the detection of pluripotency markers requires fixation of cells in most cases. Here, we report an approach with nanoparticles carrying Cy3-labeled sense oligonucleotide reporter strands coupled to gold-particles. These molecules are directly added to cultured cells without any manipulation and gene expression is evaluated microscopically after overnight incubation. To simultaneously detect gene expression in different species, probe sequences were chosen according to interspecies homology. With a common target-specific probe we could successfully demonstrate expression of the GAPDH house-keeping gene in somatic cells and expression of the pluripotency markers NANOG and GDF3 in embryonic stem cells and iPS cells of murine, human, and porcine origin. The population of target gene positive cells could be purified by fluorescence-activated cell sorting. After lentiviral transduction of murine tail-tip fibroblasts Nanog-specific probes identified truly reprogrammed murine iPS cells in situ during development based on their Cy3-fluorescence. The intensity of Nanog-specific fluorescence correlated positively with an increased capacity of individual clones to differentiate into cells of all three germ layers. Our approach offers a universal tool to detect intracellular gene expression directly in live cells of any desired origin without the need for manipulation, thus allowing conservation of the genetic background of the target cell. Furthermore, it represents an easy, scalable method for efficient screening of pluripotency which is highly desirable during high-throughput cell reprogramming and after genomic editing of pluripotent stem cells.
AU  - Lahm, H.*
AU  - Doppler, S.A.*
AU  - Dressen, M.*
AU  - Werner, A.*
AU  - Adamczyk, K.*
AU  - Schrambke, D.*
AU  - Brade, T.*
AU  - Laugwitz, K.L.*
AU  - Deutsch, M.A.*
AU  - Schiemann, M.
AU  - Lange, R.*
AU  - Moretti, A.*
AU  - Krane, M.*
C1  - 43439
C2  - 36549
CY  - Hoboken
SP  - 392-402
TI  - Live fluorescent RNA-based detection of pluripotency gene expression in embryonic and induced pluripotent stem cells of different species.
JO  - Stem Cells
VL  - 33
IS  - 2
PB  - Wiley-blackwell
PY  - 2015
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - In many solid tumors, cancer stem cells (CSC) represent a population with tumor-initiating, self-renewal, and differentiation potential, which can be identified by surface protein markers. No generally applicable markers are yet known for renal cell carcinoma (RCC). Two RCC cell lines (RCC-26, RCC-53) were found to differ widely in their capacity to form spheres in vitro and to establish tumors in mice, potentially reflecting differences in CSC content. A subpopulation expressing the CXC chemokine receptor 4 (CXCR4) was present only in the more tumorigenic cell line RCC-53. When grown as spheres, most of the RCC-53 cells were CXCR4-positive, expressed stem cell-associated transcription factor genes at elevated levels, and were more resistant toward the tyrosine kinase inhibitors sunitinib, sorafenib, and pazopanib. Sorted CXCR4-positive cells exhibited greater capacity for sphere formation and tumor growth-inducing potential in vivo than CXCR4-negative cells. Significantly, higher CXCR4 mRNA levels in primary RCC tumors from patients with localized but not disseminated disease predicted shorter survival. Downregulation of CXCR4 expression by small interfering RNA (siRNA) or pharmacological inhibition by AMD3100 compromised tumor sphere formation, viability of CXCR4-positive cells, and increased their responsiveness toward tyrosine kinase inhibitors. In conclusion, CXCR4 identifies a subpopulation of tumor-initiating cells in RCC cell lines and plays a role in their maintenance. The relative insensitivity of such cells to tyrosine kinase inhibitors might contribute to the development of therapy resistance in RCC patients. Future therapies therefore could combine blockade of the CXCR4 signaling pathway with standard therapies for more effective treatments of metastatic RCC.
AU  - Gassenmaier, M.*
AU  - Chen, D.*
AU  - Buchner, A.*
AU  - Henkel, L.
AU  - Schiemann, M.
AU  - Mack, B.*
AU  - Schendel, D.J.
AU  - Zimmermann, W.*
AU  - Pohla, H.
C1  - 27255
C2  - 32585
SP  - 1467-1476
TI  - CXC chemokine receptor 4 is essential for maintenance of renal cell carcinoma-initiating cells and predicts metastasis.
JO  - Stem Cells
VL  - 31
IS  - 8
PB  - Wiley-Blackwell
PY  - 2013
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - The identification of novel approaches to specifically target the DNA-damage checkpoint response in chemotherapy-resistant cancer stem cells (CSC) of solid tumors has recently attracted great interest. We show here in colon cancer cell lines and primary colon cancer cells that inhibition of checkpoint-modulating phosphoinositide 3-kinase-related (PIK) kinases preferentially depletes the chemoresistant and exclusively tumorigenic CD133(+) cell fraction. We observed a time- and dose-dependent disproportionally pronounced loss of CD133(+) cells and the consecutive lack of in vitro and in vivo tumorigenicity of the remaining cells. Depletion of CD133(+) cells was initiated through apoptosis of cycling CD133(+) cells and further substantiated through subsequent recruitment of quiescent CD133(+) cells into the cell cycle followed by their elimination. Models using specific PIK kinase inhibitors, somatic cell gene targeting, and RNA interference demonstrated that the observed detrimental effects of caffeine on CSC were attributable specifically to the inhibition of the PIK kinase ataxia telangiectasia- and Rad3-related (ATR). Mechanistically, phosphorylation of CHK1 checkpoint homolog (S. pombe; CHK1) was significantly enhanced in CD133(+) as compared with CD133(-) cells on treatment with DNA interstrand-crosslinking (ICL) agents, indicating a preferential activation of the ATR/CHK1-dependent DNA-damage response in tumorigenic CD133(+) cells. Consistently, the chemoresistance of CD133(+) cells toward DNA ICL agents was overcome through inhibition of ATR/CHK1-signaling. In conclusion, our study illustrates a novel target to eliminate the tumorigenic CD133(+) cell population in colon cancer and provides another rationale for the development of specific ATR-inhibitors.
AU  - Gallmeier, E.*
AU  - Hermann, P.C.*
AU  - Mueller, M.T.*
AU  - Machado, J.G.*
AU  - Ziesch, A.*
AU  - de Toni, E.N.*
AU  - Palagyi, A.*
AU  - Eisen, C.*
AU  - Ellwart, J.W.
AU  - Rivera, J.*
AU  - Rubio-Viqueira, B.*
AU  - Hidalgo, M.*
AU  - Bunz, F.*
AU  - Göke, B.*
AU  - Heeschen, C.*
C1  - 6698
C2  - 29135
SP  - 418-429
TI  - Inhibition of ataxia telangiectasia- and Rad3-related function abrogates the in vitro and in vivo tumorigenicity of human colon cancer cells through depletion of the CD133+ tumor-initiating cell fraction.
JO  - Stem Cells
VL  - 29
IS  - 3
PB  - Wiley-Blackwell
PY  - 2011
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - Embryonal endothelial progenitor cells (eEPCs) are capable of inducing therapeutic angiogenesis in a chronic hind limb model. However, the proportion of eEPCs recruited to the ischemic tissue appears to be a limiting step for the induction of cell-based therapeutic neovascularization. In the present study, we primed eEPCs with the human cathelicidin LL37 (hCAP-18) ex vivo to selectively enhance the eEPC-dependent gain of perfusion in vivo and elucidated the mechanism of action of LL37 on eEPCs. Seven days after femoral artery excision, 5 x 10(6) eEPCs (wt, wild type; p65t, transiently p65 transient; p65s, stable p65-transfected; LL37-eEPCs, LL37 peptide preincubated) were retroinfused into the anterior tibial vein. Recruitment of diI-labeled eEPCs in the ischemic gastrocnemic muscle was investigated 2 days later, whereas collateral growth and perfusion score (obtained by fluorescent microspheres) were assessed at day 7 and day 35 and are given as percentage of day 7 level. Capillary/muscle fiber ratio in the ischemic lower limb was obtained at day 35. Embryonic EPC recruitment in vitro and in vivo was found elevated after LL37 and p65t pretreatment, but not in p65s-eEPCs displaying increased IkappaBalpha or after LL37 in IkappaB-DN overexpressing eEPCs. Using LL37- and p65t-eEPCs, collateral growth (181 +/- 10% and 165 +/- 8%, respectively) surpassed that of wt-eEPCs (135 +/- 7%), increasing perfusion ratio (208 +/- 20% and 210 +/- 17% vs. 142 +/- 12% in wt-eEPCs, respectively), whereas p65s-eEPCs exerted no additive effect (collateral growth 130 +/- 8%; perfusion ratio 155 +/- 15%). Moreover, p65t-eEPC-induced neovascularization was abrogated by blocking antibodies against E-selectin and P-selectin glycoprotein ligand-1 (PSGL-1). We conclude that NF kappaB activation by LL37 or transient p65-transfection increases functionally relevant eEPC recruitment to ischemic muscle tissue via induction of PSGL-1 and E-selectin.
AU  - Pfosser, A.*
AU  - El-Aouni, C.*
AU  - Pfisterer, I.
AU  - Dietz, M.*
AU  - Globisch, F.*
AU  - Stachel, G.*
AU  - Trenkwalder, T.*
AU  - Pinkenburg, O.*
AU  - Horstkotte, J.*
AU  - Hinkel, R.*
AU  - Sperandio, M.*
AU  - Hatzopoulos, A.K.*
AU  - Boekstegers, P.*
AU  - Bals, R.*
AU  - Kupatt, C.*
C1  - 5136
C2  - 28182
CY  - Durham
SP  - 376-385
TI  - NF κB activation in embryonic endothelial progenitor cells enhances neovascularization via PSGL-1 mediated recruitment: Novel role for LL37.
JO  - Stem Cells
VL  - 28
IS  - 2
PB  - Alphamed Press
PY  - 2010
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - The neural stem cell niche of the embryonic and adult forebrain is rich in chondroitin sulfate glycosaminoglycans (CS-GAGs) that represent complex linear carbohydrate structures on the cell surface of neural stem/progenitor cells or in their intimate environment. We have reported earlier that the removal of CS-GAGs with the bacterial enzyme chondroitinase ABC (ChABC) reduced neural stem/progenitor cell proliferation and self-renewal, while this treatment favored astroglia formation at the expense of neurogenesis. Here, we studied the consequences of CS-deglycanation further and revealed that CS-GAGs are selectively required for neurosphere formation, proliferation and self-renewal of embryonic cortical neural stem/progenitor cells in response to FGF-2. Consistently, the FGF-2-dependent activation of the MAPKinase in neural stem/progenitor cells was diminished after ChABC treatment, but unaltered after EGF stimulation. Upon EGF-treatment, fewer radial glia were BLBP-positive while more were GLAST-positive after CS-GAG removal. Only in this latter situation, GLAST-positive radial glia cells extended processes that supported neuronal migration from differentiating neurospheres. CS-deglycanation also selectively increased astrocyte numbers and their migration in response to EGF. Thus, our approach revealed that CS-GAGs are essential for FGF-2-mediated proliferation and maintenance of neuron-generating neural stem/progenitor cells. Simultaneously, CS-GAGs act as a brake on the EGF-dependent maturation, migration and gliogenesis of neural stem/progenitor cells. We conclude that neural stem/progenitor cell subpopulations reside in neurospheres that are distinguishable by their responsiveness to FGF-2 and EGF that is differentially regulated by CS-carbohydrate structures.
AU  - Sirko, S.*
AU  - von Holst, A.*
AU  - Weber, A.*
AU  - Wizenmann, A.
AU  - Theocharidis, U.*
AU  - Götz, M.
AU  - Faissner, A.*
C1  - 1501
C2  - 27069
SP  - 775-787
TI  - Chondroitin sulfates are required for fibroblast growth factor-2-dependent proliferation and maintenance in neural stem cells and for epidermal growth factor-dependent migration of their progeny.
JO  - Stem Cells
VL  - 28
IS  - 4
PY  - 2010
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - The transplantation of cardiomyocytes derived from embryonic stem (ES) cells into infarcted heart has been shown to improve heart function in animal models. However, immune rejection of transplanted cells may hamper the clinical application of this approach. Natural killer (NK) cells could play an important role in this process in both autologous and allogeneic settings by eliminating cells expressing low levels of major histocompatibility complex (MHC) class I molecules. Here we characterize embryonic stem cell-derived cardiomyocytes (ESCM) in terms of their sensitivity to NK cells. We show that despite expression of very low levels of MHC class I molecules, murine ESCM were neither recognized nor lysed by activated syngeneic NK cells in vitro. In contrast, undifferentiated ES cells expressing similarly low levels of MHC class I molecules as ESCM were recognized and lysed by NK cells. This differential susceptibility results from the differential expression of ligands for the major activating natural killer cell receptor natural-killer group 2 member D (NKG2D) and intercellular adhesion molecule 1 (ICAM-1) on ES cells versus ESCM. NKG2D ligands and ICAM-1 were expressed on ES cells but were absent from ESCM. Undifferentiated ES cells were lysed by NK cells in a perforin-dependent manner. However, simultaneous blockade of NKG2D and ICAM-1 by antibodies inhibited this killing. These data suggest that in the course of differentiation ESCM acquire resistance to NK cell-mediated lysis by downregulating the expression of ligands required for activation of NK cell cytotoxicity.
AU  - Frenzel, L.P.*
AU  - Abdullah, Z.*
AU  - Kriegeskorte, A.K.
AU  - Dieterich, R.*
AU  - Lange, N.*
AU  - Busch, D.H.
AU  - Krönke, M.*
AU  - Utermöhlen, O.*
AU  - Hescheler, J.*
AU  - Saric, T.*
C1  - 1680
C2  - 26813
SP  - 307-316
TI  - Role of natural-killer group 2 member D ligands and intercellular adhesion molecule 1 in natural killer cell-mediated lysis of murine embryonic stem cells and embryonic stem cell-derived cardiomyocytes.
JO  - Stem Cells
VL  - 27
IS  - 2
PB  - Alphamed Press
PY  - 2009
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - Epithelial cell adhesion molecule EpCAM is a transmembrane glycoprotein that is expressed on subsets of normal epithelia, numerous stem- and progenitor-type cells, and most carcinomas and highly overexpressed on cancer-initiating cells. The role of EpCAM in early development, particularly in stem-like cells, has remained unclear. Here, we show that the maintenance of self-renewal in murine embryonic stem (ES) cells depends on the high-level expression of EpCAM. Cultivation of ES cells under differentiation conditions in the absence of leukemia inhibitory factor (LIF) caused down-regulation of EpCAM along with decreased expression of cellular myelocytomatosis oncogene (c-Myc), Sex-determining region Y-Box 2, Octamer 3/4 (Oct3/4), and Stat3. As a consequence ES cells were morphologically differentiated and ceased to proliferate. RNA interference-mediated inhibition of EpCAM expression under self-renewal conditions resulted in quantitatively decreased proliferation, decreased Oct3/4, SSEA-1, and c-Myc expression, and diminished alkaline phosphatase activity. Conversely, exogenous expression of EpCAM partially compensated for the requirement of ES cells for LIF to retain a stem cell phenotype. Thus, murine EpCAM is a transmembrane protein, which is essential but by itself is not sufficient for maintenance of the ES cell phenotype.
AU  - González, B.
AU  - Denzel, S.*
AU  - Mack, B.*
AU  - Conrad, M.
AU  - Gires, O.
C1  - 1457
C2  - 27083
CY  - Durham
SP  - 1782-1791
TI  - EpCAM is involved in maintenance of the murine embryonic stem cell phenotype.
JO  - Stem Cells
VL  - 27
IS  - 8
PB  - Alphamed Press
PY  - 2009
SN  - 0737-1454
ER  - 

TY  - JOUR
AB  - We investigated whether KIT signaling was sufficient to maintain human hematopoietic stem cells in culture or whether, as with murine stem cells, signaling through glycoprotein 130 (gp130) is additionally required. Sorted CD34(+) CD133(+)(CD33/CD38/CD71)(-) cells from human umbilical cord blood (UCB) were cultured in the presence of combinations of KIT-ligand (KL) and the gp130 stimulating molecule oncostatin M (OSM). We found that OSM increased KL-induced proliferation, which was accompanied by an expansion in numbers of mature progenitors colony-forming cells (CFC, CAFCw2). More primitive progenitors, CAFCw6 and long-term culture-CFC, were not maintained by KL as a single factor. Although addition of OSM did not improve survival, the KL/OSM combination showed improved maintenance of immature progenitors as well as higher CD34 expression. Similarly, both KL and OSM were required to maintain NOD/SCID-repopulating activity. In experiments to investigate the underlying mechanism, we found that extracellular signal-regulated kinase (ERK) and its downstream target p90 ribosomal S6 kinase were activated by KL and downregulated by the inclusion of OSM during stimulation. The p38 mitogen-activated protein kinase (p38 MAPK) was not modulated by either KL or OSM. Indeed, many of the effects of OSM (increased cell division, maintenance of CFC, and maintenance of high CD34 expression) could be mimicked by using the mitogen-activated protein kinase kinase inhibitor U0126. More importantly, NOD/SCID-repopulating activity was preserved in the KL/U0126-stimulated cells, but not in cells stimulated with a combination of KL and the p38 MAPK inhibitor SB203580. Our results show that the loss of repopulating activity during KL stimulation is counteracted by OSM through the downregulation of ERK pathway signaling.
AU  - Oostendorp, R.A.J.*
AU  - Gilfillan, S.*
AU  - Parmar, A.*
AU  - Schiemann, M.
AU  - Marz, S.*
AU  - Niemeyer, M.*
AU  - Schill, S.*
AU  - Hammerschmid, E.
AU  - Jacobs, V.R.*
AU  - Peschel, C.*
AU  - Götze, K.S.*
C1  - 525
C2  - 25930
SP  - 2164-2172
TI  - Oncostatin M-mediated regulation of KIT-ligand-induced extracellular signal-regulated kinase signaling maintains hematopoietic repopulating activity of Lin(-)CD34(+) CD133(+) cord blood cells.
JO  - Stem Cells
VL  - 26
IS  - 8
PB  - AlphaMed Press
PY  - 2008
SN  - 0737-1454
ER  - 

TY  - JOUR
AU  - Schneider, M.R.*
AU  - Adler, H.
AU  - Braun, J.*
AU  - Kienzle, B.*
AU  - Wolf, E.*
AU  - Kolb, H.-J.
C1  - 5194
C2  - 24460
SP  - 1850-1851
TI  - Canine embryo-derived stem cells — toward clinically relevant animal models for evaluating efficacy and safety of cell therapies.
JO  - Stem Cells
VL  - 25
PB  - AlphaMed Press
PY  - 2007
SN  - 0737-1454
ER  - 

TY  - JOUR
AU  - Huss, R.*
AU  - Lange, C.
AU  - Weissinger, E.M.
AU  - Kolb, H.-J.
AU  - Thalmeier, K.*
C1  - 21673
C2  - 19851
SP  - 252-260
TI  - Evidence of Peripheral Blood-Derived, Plastic-Adherent CD34-/low Hematopoietic Stem Cell Clones with Mesenchymal Stem Cell Characteristics.
JO  - Stem Cells
VL  - 18
PY  - 2000
SN  - 0737-1454
ER  -