Long-term expansion of functional pancreatic islets on a laminin-521 matrix and curative transplantation into diabetic mice
Ontology highlight
ABSTRACT: In this study we show, for the first time, that whole islets can be cultured and significantly expanded long-term in vitro on specific basement membrane (BM) laminin LN-521 which is a normal component of islet BMs. Isolated islets adhere and flatten to form 2-3 cell layer entities with ~10 % of all endocrine cell types proliferating after 2-5 weeks in culture. Time-lapse imaging of freshly isolated islets in suspension labeled with hypoxia and DNA degradation indicators reveals that spherical islets on LN-111 rapidly develop hypoxia and central necrosis, in contrast to islets attached to LN-521, which normal b-cell glucose responsiveness. RNA sequencing analyses reveal that freshly isolated islets express LN-521 binding integrins. Compared to other matrices, islets grown on LN-521 develop a unique expression signature, including expression of specific integrins, involved in cell adhesion and matrix production as well as proliferation. The results reveal specific LN-521-mediated effects into islet cells and suggest that use of in vitro expanded islets may significantly enhance the efficacy of islet transplantation treatment of T1D.
Project description:Experimental golden hamsters were infected with BANAL-20-236, WK-521 (a parental strain of SARS-CoV-2), and WK-521 dFCS (a WK-521 without furin cleavage site [FCS]) to investigate virological properties and host response in vivo.
Project description:Pancreatic islet transplantation as a cure for type 1 diabetes (T1D) cannot be scaled up due to a scarcity of human pancreas donors. In vitro expansion of beta cells from mature human pancreatic islets provides an alternative source of insulin-producing cells. The exact nature of the expanded cells produced by diverse expansion protocols, and their potential for differentiation into functional beta cells, remain elusive. We performed a large-scale meta-analysis of gene expression in human pancreatic islet cells, which were processed using three different previously described protocols for expansion and attempted re-differentiation. All three expansion protocols induced dramatic changes in the expression profiles of pancreatic islets; many of these changes are shared among the three protocols. Attempts at re-differentiation of expanded cells induce a limited number of gene expression changes. Nevertheless, these fail to restore a pancreatic islet-like gene expression pattern. Comparison with a collection of public microarray datasets confirmed that expanded cells are highly comparable to mesenchymal stem cells. Genes induced in expanded cells are also enriched for targets of transcription factors important for pluripotency induction. The present data increases our understanding of the active pathways in expanded and re-differentiated islets. Knowledge of the mesenchymal stem cell potential may help development of drug therapeutics to restore beta cell mass in T1D patients. Experiment Overall Design: In this study, we have tested three different protocols to expand human pancreatic islets in monolayer and after attempted maneuvers to re-differentiate the expanded cells back to islets. We have characterized the resulting cells in detail by performing microarray analyses with fresh pancreatic islets, expanded islet cells and re-differentiated cells. Genes modified by either of three protocols have 70 to 80% overlap with the genes changed by the other two protocols. Although there are promising changes in the right direction, none of the three protocols could achieve a return to a functional islet state. The expanded cells highly resemble Mesenchymal Stem Cells (MSC), and similar gene regulatory networks seem to be active in both cell types. On the other hand, the expanded islet cells are different from MSC in that they seem to retain activity of some islet gene modules. The current results highlight the importance of designing new strategies that take into account the MSC potential of expanded cells.
Project description:iPSC-derived human airway cells and colon organoids were infected with BANAL-20-236, SARS-CoV-2 (WK-521), and FCS-deleted SARS-CoV-2 (WK-521 dFCS) to investigate virological properties and reaction of infected hosts.
Project description:M-NM-2-cell identity is determined by tightly regulated transcriptional networks that are modulated by extracellular cues, thereby ensuring M-NM-2-cell adaptation to the organismM-bM-^@M-^Ys insulin demands. We have observed in pancreatic islets that stimulatory glucose concentrations induced a gene profile that was similar to that of freshly isolated islets, indicating that glucose-elicited cues are involved in maintaining M-NM-2-cell identity. Low glucose induces the expression of ubiquitous genes involved in stress responses, nutrient sensing, and organelle biogenesis. By contrast, stimulatory glucose concentrations activate genes with a more restricted expression pattern (M-NM-2- and neuronal- cell identity). Consistently, glucose-induced genes are globally reduced in islets deficient with Hnf1a (MODY3), characterized by a deficient glucose metabolism. Of interest, a cell cycle gene module was the most enriched among the variable genes between intermediate and stimulatory glucose concentrations. Glucose regulation of the islet transcriptome was unexpectedly broadly maintained in islets from aged mice. However, the cell cycle gene module is selectively lost in old islets and the glucose activation of this module is not recovered even in the absence of the cell cycle inhibitor p16. We used microarrays to detail the global programme of gene expression regulated by glucose in young and aged pancreatic islets as well as freshly-isolated islets. Pancreatic islets from young and old mice were isolated and cultured at different glucose concentrations for RNA extraction and hybridization on Affymetrix microarrays. Islets were cultured at 3mM (G3), 5.5mM (G5), 11mM (G11) and 16mM (G16). Freshly-isolated islets (F) were also processed for RNA extraction . We also assessed the dynamic glucose regulation of gene expression at different time-points after an overnight at 3mM (T0): after 1h at 11mM (T1) and after 4h (T4).
Project description:Stem cell-derived islet (SC-islet) cell therapy holds immense potential for the treatment of Type 1 Diabetes. However, low oxygen supply leads to cell dysfunction post-transplantation, especially in subcutaneous spaces and encapsulation devices. The response of SC-islets to hypoxia and effective strategies to alleviate its detrimental effects remain poorly understood. This study investigates the impact of hypoxia on SC-islets and elucidate the dynamics of hypoxia-induced stress. We performed transcriptional profiling of human SC-islets exposed to hypoxic conditions, and drew the transcriptomic and epigenetic profiles of single cells. Our findings demonstrate that β cells within SC-islets gradually undergo a decline in cell identity and metabolic function in response to hypoxia. The loss of expression from immediate early genes, specifically EGR1, FOS, and JUN, results in the downregulation of key transcription factors (TFs) that are essential for maintaining SC-islet cell identity under hypoxic conditions. By comparing SC-islets under low and high oxygen conditions, we identified genes that play a role in maintaining the fitness of SC-islets in a low-oxygen environment. Notably, the expression of EDN3, a potent vasoconstrictor gene that is enriched in native pancreatic β cells, significantly aids in preserving β cell identity under hypoxic conditions. Elevated expression of EDN3 in SC-islets effectively mitigated the deleterious effects of hypoxia by modulating genes involved in SC-islet maturation including genes associated with glucose sensing and regulation in β cells. These insights improve the understanding of SC-islets under hypoxic conditions, offering a potential point of intervention for future clinical applications in the treatment of Type 1 Diabetes
Project description:β-cell identity is determined by tightly regulated transcriptional networks that are modulated by extracellular cues, thereby ensuring β-cell adaptation to the organism’s insulin demands. We have observed in pancreatic islets that stimulatory glucose concentrations induced a gene profile that was similar to that of freshly isolated islets, indicating that glucose-elicited cues are involved in maintaining β-cell identity. Low glucose induces the expression of ubiquitous genes involved in stress responses, nutrient sensing, and organelle biogenesis. By contrast, stimulatory glucose concentrations activate genes with a more restricted expression pattern (β- and neuronal- cell identity). Consistently, glucose-induced genes are globally reduced in islets deficient with Hnf1a (MODY3), characterized by a deficient glucose metabolism. Of interest, a cell cycle gene module was the most enriched among the variable genes between intermediate and stimulatory glucose concentrations. Glucose regulation of the islet transcriptome was unexpectedly broadly maintained in islets from aged mice. However, the cell cycle gene module is selectively lost in old islets and the glucose activation of this module is not recovered even in the absence of the cell cycle inhibitor p16. We used microarrays to detail the global programme of gene expression regulated by glucose in young and aged pancreatic islets as well as freshly-isolated islets.
Project description:β-cell specific Mettl14 knock-out mice display reduced N6-methyladenosine (m6A) levels and recapitulate human Type II diabetes (T2D) islet phenotype with early diabetes onset and mortality secondary to decreased β-cell proliferation and insulin degranulation. To gain insights into the role of m6A in regulating the IGF1/insulin -> AKT - > PDX1 pathway and to dissect the signaling networks modulating AKT phosphorylation, we subjected freshly isolated islets from control and Mettl14 knock-out mice to phospho-antibody microarrays.