Project description:In vitro expansion of adult human islet β cells is an attractive solution for the shortage of tissue for cell replacement therapy of type 1 diabetes. Using a lineage tracing approach, we have demonstrated that β-cell-derived (BCD) cells rapidly dedifferentiate in culture and can proliferate for up to 16 population doublings. Dedifferentiation is associated with changes resembling epithelial-mesenchymal transition (EMT). The WNT pathway has been shown to induce EMT and plays key roles in regulating replication and differentiation in many cell types. Here we show that BCD cell dedifferentiation is associated with β-catenin translocation into the nucleus and activation of the WNT pathway. Inhibition of β-catenin expression in expanded BCD cells using short hairpin RNA resulted in growth arrest, mesenchymal-epithelial transition, and redifferentiation, as judged by activation of β-cell gene expression. Furthermore, inhibition of β-catenin expression synergized with redifferentiation induced by a combination of soluble factors, as judged by an increase in the number of C-peptide-positive cells. Simultaneous inhibition of the WNT and NOTCH pathways also resulted in a synergistic effect on redifferentiation. These findings, which were reproducible in cells derived from multiple human donors, suggest that inhibition of the WNT pathway may contribute to a therapeutically applicable way for generation of functional insulin-producing cells following ex-vivo expansion.
Project description:In vitro expansion of adult human islet M-NM-2 cells is an attractive solution for the shortage of tissue for cell replacement therapy of type 1 diabetes. Using a lineage tracing approach, we have demonstrated that M-NM-2-cell-derived (BCD) cells rapidly dedifferentiate in culture and can proliferate for up to 16 population doublings. Dedifferentiation is associated with changes resembling epithelial-mesenchymal transition (EMT). The WNT pathway has been shown to induce EMT and plays key roles in regulating replication and differentiation in many cell types. Here we show that BCD cell dedifferentiation is associated with M-NM-2-catenin translocation into the nucleus and activation of the WNT pathway. Inhibition of M-NM-2-catenin expression in expanded BCD cells using short hairpin RNA resulted in growth arrest, mesenchymal-epithelial transition, and redifferentiation, as judged by activation of M-NM-2-cell gene expression. Furthermore, inhibition of M-NM-2-catenin expression synergized with redifferentiation induced by a combination of soluble factors, as judged by an increase in the number of C-peptide-positive cells. Simultaneous inhibition of the WNT and NOTCH pathways also resulted in a synergistic effect on redifferentiation. These findings, which were reproducible in cells derived from multiple human donors, suggest that inhibition of the WNT pathway may contribute to a therapeutically applicable way for generation of functional insulin-producing cells following ex-vivo expansion. Gene expression was studied for beta-cells (4 donors). Dedifferentiation was induced by inhibition of M-NM-2-catenin expression using shRNA. The experiment was performed in 4 batches (see the 'Date' characteristic in the Sample records).
Project description:Expansion of beta cells from the limited number of adult human islet donors is an attractive prospect for increasing cell availability for cell therapy of diabetes. However, while evidence supports the replicative capacity of adult beta cells in vivo, attempts at expanding human islet cells in tissue culture resulted in loss of beta-cell phenotype. Using a genetic lineage-tracing approach we have provided evidence for massive proliferation of beta-cell-derived (BCD) cells within these cultures. Expansion involves dedifferentiation resembling epithelial-mesenchymal transition (EMT). Epigenetic analyses indicate that key beta-cell genes maintain a partially open chromatin structure in expanded BCD cells, although they are not transcribed. Here we report that BCD cells can be induced to redifferentiate by a combination of soluble factors. The redifferentiated cells express beta-cell genes, store insulin in typical secretory vesicles, and release it in response to glucose. The redifferentiation process involves mesenchymal-epithelial transition, as judged from changes in gene expression. Moreover, inhibition of the EMT effector SLUG using shRNA results in stimulation of redifferentiation. BCD cells also give rise at a low rate to cells expressing other islet hormones, suggesting transition through an islet progenitor-like stage during redifferentiation. These findings suggest that ex-vivo expansion of adult human islet cells is a promising approach for generation of insulin-producing cells for transplantation, as well as basic research, toxicology studies, and drug screening. Gene expression was studied in unexpanded islets (4 donors), expanded and dedifferentiated islet cells (4 donors), and re-differentiated islet cells (3 donors). The experiment was performed in 3 batches (see Date in the description table below).
Project description:In-vitro expansion of functional adult human β-cells is an attractive approach for generating insulin-producing cells for transplantation. However, human islet cell expansion in culture results in loss of β-cell phenotype and epithelial-mesenchymal transition (EMT). This process activates expression of ZEB1 and ZEB2, two members of the zinc-finger homeobox family of E-cadherin repressors, which play key roles in EMT. Downregulation of ZEB1 using shRNA in expanded β-cell-derived (BCD) cells induced mesenchymal-epithelial transition (MET), β-cell gene expression, and proliferation attenuation. In addition, inhibition of ZEB1 expression potentiated redifferentiation induced by a combination of soluble factors, as judged by an improved response to glucose stimulation and a 3-fold increase in the fraction of C-peptide-positive cells to 60% of BCD cells. Furthermore, ZEB1 shRNA led to increased insulin secretion in cells transplanted in vivo. Our findings suggest that the effects of ZEB1 inhibition are mediated by attenuation of the miR-200c target genes SOX6 and SOX2. These findings, which were reproducible in cells derived from multiple human donors, emphasize the key role of ZEB1 in EMT in cultured BCD cells and support the value of ZEB1 inhibition for BCD cell redifferentiation and generation of functional human β-like cells for cell therapy of diabetes.
Project description:Expansion of beta cells from the limited number of adult human islet donors is an attractive prospect for increasing cell availability for cell therapy of diabetes. However, while evidence supports the replicative capacity of adult beta cells in vivo, attempts at expanding human islet cells in tissue culture resulted in loss of beta-cell phenotype. Using a genetic lineage-tracing approach we have provided evidence for massive proliferation of beta-cell-derived (BCD) cells within these cultures. Expansion involves dedifferentiation resembling epithelial-mesenchymal transition (EMT). Epigenetic analyses indicate that key beta-cell genes maintain a partially open chromatin structure in expanded BCD cells, although they are not transcribed. Here we report that BCD cells can be induced to redifferentiate by a combination of soluble factors. The redifferentiated cells express beta-cell genes, store insulin in typical secretory vesicles, and release it in response to glucose. The redifferentiation process involves mesenchymal-epithelial transition, as judged from changes in gene expression. Moreover, inhibition of the EMT effector SLUG using shRNA results in stimulation of redifferentiation. BCD cells also give rise at a low rate to cells expressing other islet hormones, suggesting transition through an islet progenitor-like stage during redifferentiation. These findings suggest that ex-vivo expansion of adult human islet cells is a promising approach for generation of insulin-producing cells for transplantation, as well as basic research, toxicology studies, and drug screening.
Project description:We aimed to assess whether Wnt-modulation could contribute to mature hiPSC-derived insulin-producing cells in vitro. Building our hypothesis on our previous findings of Wnt activation in immature hiPSC-derived insulin-producing cells compared to adult human islets and with recent data reporting a link between Wnt/PCP and in vitro beta-cell maturation. In this study we stimulated hiPSC-derived insulin-producing cells with syntetic proteins including WNT3A, WNT4, WNT5A and WNT5B as well as inhibiting endogeneous Wnt signaling with Tankyrase inhibitor G007-LK.
Project description:The inability of the adult mammalian heart to regenerate represents a fundamental barrier in heart failure management. In contrast, the neonatal heart retains a transient regenerative capacity, but the underlying mechanisms are not fully understood. Wnt/β-catenin signaling has been suggested as a key cardio-regenerative pathway. Here, we show that Wnt/β-catenin signaling potentiates neonatal mouse cardiomyocyte proliferation in vivo and immature human pluripotent stem cell-derived cardiomyocyte (hPSC-CM) proliferation in vitro. In contrast, Wnt/β-catenin signaling in adult mice is cardioprotective but fails to induce cardiomyocyte proliferation. Transcriptional profiling of neonatal mouse and hPSC-CM revealed a core Wnt/β-catenin-dependent transcriptional network governing cardiomyocyte proliferation. In contrast, β-catenin failed to re-engage this proliferative gene network in the adult heart, which instead reverted to a neonatal-like glycolytic program. These findings suggest that Wnt/β-catenin drives distinct transcriptional networks in regenerative and non-regenerative cardiomyocytes, which may contribute towards the inability of the adult heart to regenerate following injury.
Project description:Analysis of mobilized peripheral blood CD34+ cells from a healthy volunteer under erythroid differentiation conditions with and without stimulation to the BMP or Wnt signaling pathways. For erythroid differentiation, expanded CD34+ cells were placed in Stemspan SFEM medium supplemented with 2% pen/strep, 20ng/ml SCF, 1U/ml Epo, 5ng/ml IL3, 2uM dexamethasone, and 1uM beta-estradiol. Arrays were performed 2 hours after addition of cytokines. For signaling pathway stimulation, cells were exposed to 0.5uM BIO (a GSK3 inhibitor) for Wnt pathway activation, 25ng/ml rhBMP4 for BMP pathway activation, or vehicle control for 2 hours. Three biological replicates were performed per treatment group. We used microarrays to detail the global program of gene expression changes after Wnt or BMP pathway stimulation in human CD34+ hematopoietic progenitors under erythroid differentiation conditions. To investigate the changes to gene expression in human CD34+ hematopoietic progenitors following stimulation of the Wnt or BMP pathways during the early stages of erythroid differentiation. Three biological replicates were performed per treatment group.