ABSTRACT: Zinc finger protein ZBTB20 plays a critical role in regulating insulin expression from islet beta-cells by orchestrating their gene expression profile. We used microarrays to investigate the target gene of ZBTB20 in mouse pancreatic beta-cells. Adult mouse islets were harvested for RNA extraction and hybridization on Affymetrix microarrays. We sought to identify the target genes of transcription factor ZBTB20 in beta-cells. To that end, we isolated the islets from adult beta cell-specific ZBTB20 knockout and their littermate control mice.
Project description:Zinc finger protein ZBTB20 plays a critical role in mouse hippocampal development by orchestrating gene expression profile of hippocampal neurons. We used microarrays to investigate the target gene of ZBTB20 in mouse hippocampal development. Mouse hippocampi were harvested at postnatal day 2 for RNA extraction and hybridization on Affymetrix microarrays. We sought to identify the target genes of transcription factor ZBTB20 in hippocampal development. To that end, we isolated the hippocampi from ZBTB20 knockout and their littermate control mice.
Project description:Zinc finger protein ZBTB20 plays a critical role in regulating insulin expression from islet beta-cells by orchestrating their gene expression profile. We used microarrays to investigate the target gene of ZBTB20 in mouse pancreatic beta-cells.
Project description:During pregnancy, pancreatic islets undergo structural and functional changes that lead to enhance insulin release in response to increased insulin demand, which is rapidly reversed at parturition. One of the most important changes is expansion of pancreatic β-cell mass mainly by increased proliferation of β cells. We used microarrays to detail the global programme of gene expression and identified distinct up- or down-regulated genes during pregnancy. Maternal islet were isolated from mice at dpc 0 and 12.5 dpc of pregnancy for RNA extraction and hybridization on Affymetrix microarrays. We sought to identify the responsible factors for the proliferation of islets during pregnancy.
Project description:The study was completed to compare expression profiles of primary human beta cells (in the form of adult human islets), to the expression profile of hESC-derived beta-like cells. A HES3 line modified by homologous recombination to express GFP under the insulin promoter allowed us to FACS sort the hESC-derived cells into purified insulin-positive (presumably beta-like cells), and insulin-negative populations. Expression profile of adult human islets from cadaveric donors is compared to insulin-positive and insulin-negative populations of hESC-derived beta-like cells
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:The zinc finger factor Insm1 is known to regulate differentiation of pancreatic ? cells during development, Here we show that Insm1 is essential for the maintenance of functionally mature pancreatic ? cells in mice. We used microarrays to analyse the global gene expression after deletion of insm1 in adult pancreatic ? cells and identified functional important genes and immature islets releated genes deregulated in the mutatant islets. We used 8 mutant and 8 litter matched control mice for the islets preparation.
Project description:The zinc finger factor Insm1 is known to regulate differentiation of pancreatic β cells during development, Here we show that Insm1 is essential for the maintenance of functionally mature pancreatic β cells in mice. We used microarrays to analyse the global gene expression after deletion of insm1 in adult pancreatic β cells and identified functional important genes and immature islets releated genes deregulated in the mutatant islets.
Project description:insulin treatment protects islets from the initial rapid loss that is usually observed after transplantation and positively affects the outcome of islet transplantation in Akita mice. To study the molecular mechanism underlying the improved islet survival, expression profile analyses was performed to analyze the differences between the grafts transplanted into hyperglycemic and normoglycemic mice at 6 hours post-transplantation Cells were harvested at grafts for RNA extraction and hybridization on Affymetrix microarrays. We performed gene expression profiles of the transplanted mouse islets into hyperglycemic and normoglycemic mice at 6 hours post-transplantation
Project description:Changes in the secretion profile of visceral-pancreatic white adipose tissue (pWAT) due to diet-induced obesity are partially responsible for increased beta cell replication, suggesting that a crosstalk between pWAT and beta cells may play a role in regulating beta cell plasticity. The molecular mechanisms underlying this cross-talk are still not fully understood. The aim of this study was to integrate transcriptomic, proteomic and metabolomic data to unravel the cross-talk between adipose tissue and pancreatic islets during evolution of obesity. Pancreatic islets from control lean and cafeteria diet fed obese rats were obtained. RNA was extracted and processed for further hybridization on Affymetrix microarrays (GeneChip Rat Genome 230 2.0 (Affymetrix, Santa Clara, CA)).
Project description:The activity of pancreatic islets’ insulin-producing β-cells is closely regulated by systemic cues and, locally, by adjacent islet hormone-producing “non-β-cells” (namely α-, δ- and γ-cells). Still, it is unclear whether the presence of the non-β-cells is a requirement for accurate insulin secretion. Here, we generated and studied a mouse model in which adult islets are exclusively composed of β-cells, and human pseudoislets containing only primary β-cells. Mice lacking non-β-cells had optimal blood glucose regulation. They exhibited enhanced glucose tolerance, insulin sensitivity and restricted body weight gain under high-fat diet. The insulin secretion dynamics in islets composed of only β-cells was like in intact islets, both in homeostatic conditions and upon extreme insulin demand. Similarly, human β-cell pseudoislets retained the glucose-regulated mitochondrial respiration, insulin secretion and exendin-4 responses of human islets comprising all four cell types. Together, the findings indicate that non-β-cells are dispensable for blood glucose homeostasis and β-cell function. This is particularly relevant in diabetes, where non-β-cells become dysfunctional and worsen the disease’s pathophysiology. These results support efforts aimed at developing diabetes treatments by generating β-like cell clusters devoid of non-β-cells, as for example from human embryonic stem cells and/or by in situ conversion of non-β-cells into insulin producers.