Project description:Pancreatic islet beta cell heterogeneity has been identified, which plays a pivotal role in the pathological alterations of pancreatic islets in type 2 diabetes (T2D) mice. However, pathological alterations of beta cells in type 2 diabetes (T2D) mice remain to be investigated. We isolated pancreatic islets from the control and T2D mice and conducted scRNA-seq analysis using the 10x Genomics platform. Pathological alterations of beta cells in T2D were also explored.
Project description:Single-cell RNA sequencing of pancreatic islets from 18-week-old male New Zealand Obese (NZO/HIBomDife) and B6.V-Lepob/ob (OB) mice were fed a standard diet or a carbohydrate-enriched diet for 2 additional days (+CH / -CH).
Project description:Objective: beta-cell dedifferentiation has been revealed as a pathological mechanism underlying pancreatic dysfunction in diabetes. However, exactly how such dedifferentiation process affects beta-cell gene expression and islet microenvironment remains incompletely understood Method: We performed single-cell RNA-Sequencing (RNA-seq) in islets obtained from beta-cell-specific miR-7a2 overexpressing mice (Tg7), a murine model of beta-cell dedifferentiation and diabetes. Results: Single-cell RNA-seq revealed that beta-cell dedifferentiation is associated with the induction of genes associated with epithelial to mesenchymal transition (EMT) specifically in beta-cells of diabetic (12-week-old) Tg7 mice. These molecular changes are associated with a weakening of beta-cell:beta-cell contacts, increased extracellular matrix (ECM) deposition and TGFb-dependent islet fibrosis. We find that the mesenchymal reprogramming of beta-cells is explained in part by the downregulation of Pdx1 and its inability to regulate a myriad of target genes preserving the epithelial cell phenotype. Notable among epithelial genes transactivated by Pdx1 is Ovol2, a transcriptional repressor of the EMT transcription factor ZEB2. Following compromised beta-cell identity, the reduction of Pdx1 mRNA levels decreases Ovol2 gene expression, which triggers mesenchymal reprogramming of beta-cells through the induction of Zeb2. Finally, we provided evidence that EMT signalling associated with the upregulation of Zeb2 expression is a molecular feature of islet of T2D subjects. Conclusions: Our study indicates that beta-cell dedifferentiation triggers a chronic response to tissue injury, which alters the pancreatic islet microenvironment and contribute to islet fibrosis. It suggests that regulators of EMT signalling may represent novel therapeutic targets for the treatment of beta-cell dysfunction and fibrosis in T2D.
Project description:Pancreas specific deletion of the Haster promoter region results in a variegated phenotype in pancreatic islets with overexpression or silencing of the Hnf1a gene. To determine the transcriptional consequence of the overexpression or silencing of Hnf1a is islet cells from the Haster pKO mice (Haster loxP/loxP;Pdx1-Cre), we performed scRNA-seq of pancreatic islets from control and adult female Haster pKO mice.
Project description:Single-cell RNA sequencing of pancreatic islets from adult male mice. To disect islet heterogeneity we sorted cells based on anatomical location and maturity marker (Fltp).