Project description:Mouse strains like NZO and B6-ob/ob differ in their susceptibility to diet-induced diabetes. Comparison of the islet transcriptomes already revealed different biological processes, here we focused on alternative splicing events as one possible mechanism.
Project description:Alternative splicing (AS) within the β cell has been proposed as one potential pathway that may exacerbate autoimmunity and unveil novel immunogenic epitopes in type 1 diabetes (T1D). We employed a computational strategy to prioritize pathogenic splicing events in human islets treated with IL-1β + IFN-γ as an ex vivo model of T1D and coupled this analysis with a k-mer based approach to predict RNA binding proteins involved in AS events. In total, 969 AS events were identified in cytokine-treated islets, with the majority (44.8%) involving a skipped exon. AS events occurred with high frequency in MHC Class II-related mRNAs, and targeted qPCR validated reduced inclusion of Exon5 in the MHC Class II gene HLA-DMB, while RNA FISH confirmed HLA-DMB splicing in pancreatic sections from human T1D donors. Together, these data suggest that dynamic control of AS plays a role in the β cell response to inflammatory signals during T1D evolution.
Project description:Single-cell RNA sequencing of pancreatic islets from obese mice with different diabetes risk reveals diabetes-susceptible β cell clusters
Project description:Obesity is a strong risk factor for the development of type 2 diabetes. We have previously reported that in adipose tissue of obese (ob/ob) mice, the expression of adipogenic genes is decreased. When made genetically obese, the BTBR mouse strain is diabetes susceptible and the C57BL/6J (B6) strain is diabetes resistant. We used DNA microarrays and RT-PCR to compare the gene expression in BTBR-ob/ob versus B6-ob/ob mice in adipose tissue, liver, skeletal muscle, and pancreatic islets. Our results show: 1) there is an increased expression of genes involved in inflammation in adipose tissue of diabetic mice; 2) lipogenic gene expression was lower in adipose tissue of diabetes-susceptible mice, and it continued to decrease with the development of diabetes, compared with diabetes-resistant obese mice; 3) hepatic expression of lipogenic enzymes was increased and the hepatic triglyceride content was greatly elevated in diabetes-resistant obese mice; 4) hepatic expression of gluconeogenic genes was suppressed at the prediabetic stage but not at the onset of diabetes; and 5) genes normally not expressed in skeletal muscle and pancreatic islets were expressed in these tissues in the diabetic mice. We propose that increased hepatic lipogenic capacity protects the B6-ob/ob mice from the development of type 2 diabetes. Diabetes 52:688â700, 2003 Experiment Overall Design: Four B6-ob/ob and four BTBR-ob/ob male mice at 14 weeks of age were used in the microarray study. RNA samples from two individuals were pooled for each tissue, and each pooled RNA sample was applied to an Affymetrix MGU74AV2 array. Because of the scarcity of islets in the BTBR-ob/ob mice, 4 additional mice were pooled to obtain islet RNA from these animals. Sixteen MGU74Av2 arrays (2 strains X 4 tissues X 2 replicates = 16 arrays) were used to monitor the expression level of â12,000 genes or ESTs.
Project description:Diabetes-resistant and diabetes-prone female New Zealand Obese mice were classified based on liver fat content and early blood glucose concentrations at 10 weeks of age before the onset of T2D. By using transcriptome and DNA methylome analysis of Langerhans islets, we identified early epigenetic alteration in mice and humans which could serve as putative epigenetic biomarkers
Project description:In type 2 diabetes, pancreatic beta-cells fail to compensate for the presence of insulin resistance in target tissues and represent a central player in the disease development. Identifying and studying innovative molecular mechanisms that lead to beta-cell failure in diabetes represent an interesting line of research and are necessary. N6-Methyladenosine (m6A) is the most abundant modification in mRNA and is found virtually in all mammals. Through m6A-profiling, we aim to characterize the dynamic RNA methylation changes in islets obtained from patients with type 2 diabetes.
Project description:Pluripotent stem cell-derived islets (hPSC-islets) are a promising cell resource for diabetes treatment. Here, we demonstrate that transplantation of pluripotent stem cell-derived islets into diabetic nonprimates effectively restored endogenous insulin secretion and improved glycemic control. Single-cell RNA sequencing analysis of S6D2 clusters confirmed the existence of the three major pancreatic endocrine cell populations (β cells, α-like cells and δ-like cells) and their proportions, which altogether accounted for 80%. Importantly, hierarchical clustering of S6D2 hCiPSC-islets, 10 wpt kidney grafts and primary islets showed that the hCiPSC differentiated pancreatic endocrine cells shared similar global gene expression profiles to their native counterparts in primary islets. Single-cell RNA sequencing analysis on PBMCs revealed the potential immune response of recipient macaque to hCiPSC-islets.
Project description:Human pluripotent stem cell-derived islets (hPSC-islets) are a promising cell resource for diabetes treatment. Here, we demonstrate that transplantation of human pluripotent stem cell-derived islets into diabetic nonhuman primates effectively restored endogenous insulin secretion and improved glycemic control. Single-cell RNA sequencing analysis of S6D2 clusters confirmed the existence of the three major pancreatic endocrine cell populations (β cells, α-like cells and δ-like cells) and their proportions, which altogether accounted for 80%. Importantly, hierarchical clustering of S6D2 hCiPSC-islets, 10 wpt kidney grafts and primary human islets showed that the hCiPSC differentiated pancreatic endocrine cells shared similar global gene expression profiles to their native counterparts in primary human islets. Single-cell RNA sequencing analysis on PBMCs revealed the potential immune response of recipient macaque to hCiPSC-islets.
Project description:Human pluripotent stem cell-derived islets (hPSC-islets) are a promising cell resource for diabetes treatment. Here, we demonstrate that transplantation of human pluripotent stem cell-derived islets into diabetic nonhuman primates effectively restored endogenous insulin secretion and improved glycemic control. Single-cell RNA sequencing analysis of S6D2 clusters confirmed the existence of the three major pancreatic endocrine cell populations (β cells, α-like cells and δ-like cells) and their proportions, which altogether accounted for 80%. Importantly, hierarchical clustering of S6D2 hCiPSC-islets, 10 wpt kidney grafts and primary human islets showed that the hCiPSC differentiated pancreatic endocrine cells shared similar global gene expression profiles to their native counterparts in primary human islets. Single-cell RNA sequencing analysis on PBMCs revealed the potential immune response of recipient macaque to hCiPSC-islets.