Expression data from fresh and cultured islets at different glucose concentrations
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE42591 | GEO | 2013/07/01
SECONDARY ACCESSION(S): PRJNA182382
REPOSITORIES: GEO
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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).
2013-07-01 | E-GEOD-42591 | biostudies-arrayexpress
Project description:Reactive oxygen species (ROS) have been implicated as mediators of pancreatic β-cell damage. While β-cells are thought to be vulnerable to oxidative damage, we have shown, using inhibitors and acute depletions, that thioredoxin reductase, thioredoxin, and peroxiredoxins are the primary mediators of antioxidant defense in β-cells. However, the role of this antioxidant cycle in maintaining redox homeostasis and β-cell survival in vivo remains unclear. Here, we generated mice with a β-cell specific knockout of thioredoxin reductase 1 (Txnrd1.fl/fl; Ins1.Cre/+, βKO). Despite blunted glucose-stimulated insulin secretion, knockout mice maintain normal whole body glucose homeostasis. Unlike pancreatic islets with acute Txnrd1 inhibition, βKO islets do not demonstrate increased sensitivity to continuous ROS. RNA-sequencing analysis revealed that Txnrd1-deficient β-cells have increased expression of Nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated genes, and altered expression of genes involved in heme and glutathione metabolism, suggesting an adaptive response. Txnrd1-deficient β-cells also have decreased expression of factors controlling β-cell function and identity which may explain the mild functional impairment. Together, these results suggest that Txnrd1-knockout β-cells compensate for loss of this essential antioxidant pathway by increasing expression of Nrf2-regulated antioxidant genes, allowing for protection from excess ROS at the expense of normal β-cell function and identity.
2022-07-05 | GSE200965 | GEO
Project description:Pancreatic β-cells are responsible for production and secretion of insulin in response to increasing blood glucose levels. Therefore, defects in pancreatic β-cell function lead to hyperglycemia and diabetes mellitus. Understanding the molecular mechanisms governing β cell function is crucial for development of novel treatment strategies for this disease. The aim of this project was to investigate the role of Cnot3, part of CCR4-NOT complex, major deadenylase complex in mammals, in pancreatic β cell function. Cnot3βKO islets display decreased expression of key regulators of β cell maturation and function. Moreover, they show an increase of progenitor cell markers, β cell-disallowed genes and genes relevant to altered β cell function. Cnot3βKO islets exhibit altered deadenylation and increased mRNA stability, partly accounting for the increase of those genes. Together, these data reveal that CNOT3-mediated mRNA deadenylation and decay constitute previously unsuspected post-transcriptional mechanisms essential for β cell identity.
2020-08-31 | PXD018403 | Pride
Project description:Although persistent elevations in circulating glucose concentrations promote compensatory increases in pancreatic islet mass, unremitting insulin resistance causes a deterioration in beta cell function that disrupts glucose balance and signals the progression to diabetes 1. Glucagon like Peptide 1 (GLP1) agonists improve glucose tolerance in insulin resistance, although some individuals are unresponsive to treatment. Here we show that increases in GLP1 during feeding promote beta cell function in part through the PKA-mediated activation of CREB and its coactivator CRTC2 2. Mice with a knockout of CRTC2 in beta cells have impaired oral glucose tolerance due to decreases in circulating insulin concentrations. CRTC2 was found to promote beta cell function in part by stimulating the expression of the transcription factor MafA. Chronic hyperglycemia associated with high fat or high carbohydrate diet feeding disrupted cAMP signaling in pancreatic islets. Indeed, prolonged elevations in circulating glucose concentrations interfered with CREB signaling by activating the mTOR pathway and triggering the hypoxia inducible factor (HIF1)-dependent induction of the Protein Kinase A Inhibitor beta (PKIB), a potent inhibitor of PKA catalytic activity 3. As disruption of the PKIB gene restored glucose tolerance and insulin secretion in obesity, our results demonstrate how cross-talk between nutrient and hormonal pathways contributes to loss of pancreatic islet function in insulin resistance. Rat insulinoma cells were used to interrogate the impact of glucose exposure and CREB activity on cAMP dependent gene regulation in the pancreatic beta cells
2015-02-23 | E-GEOD-60158 | biostudies-arrayexpress
Project description:Although persistent elevations in circulating glucose concentrations promote compensatory increases in pancreatic islet mass, unremitting insulin resistance causes a deterioration in beta cell function that disrupts glucose balance and signals the progression to diabetes 1. Glucagon like Peptide 1 (GLP1) agonists improve glucose tolerance in insulin resistance, although some individuals are unresponsive to treatment. Here we show that increases in GLP1 during feeding promote beta cell function in part through the PKA-mediated activation of CREB and its coactivator CRTC2 2. Mice with a knockout of CRTC2 in beta cells have impaired oral glucose tolerance due to decreases in circulating insulin concentrations. CRTC2 was found to promote beta cell function in part by stimulating the expression of the transcription factor MafA. Chronic hyperglycemia associated with high fat or high carbohydrate diet feeding disrupted cAMP signaling in pancreatic islets. Indeed, prolonged elevations in circulating glucose concentrations interfered with CREB signaling by activating the mTOR pathway and triggering the hypoxia inducible factor (HIF1)-dependent induction of the Protein Kinase A Inhibitor beta (PKIB), a potent inhibitor of PKA catalytic activity 3. As disruption of the PKIB gene restored glucose tolerance and insulin secretion in obesity, our results demonstrate how cross-talk between nutrient and hormonal pathways contributes to loss of pancreatic islet function in insulin resistance.
2015-02-23 | GSE60158 | GEO
Project description:Diabetes mellitus is a complex and heterogeneous disease that has β cell dysfunction at its core. Glucose toxicity affects pancreatic islets where it leads to β cell apoptosis. However, the role of JNK/β-catenin signaling pathway in glucotoxic β-cell apoptosis is poorly understood. To identify the potential genes whose expression changed in response to high glucose, we performed microarray analysis of gene expression in the RNAKT-15 cells for 48 h. Among the 41,000 genes tested, 1394 and 741 were twofold-upregulated and -downregulated, respectively. Genes involved in carbohydrate metabolism, cell cycle control, apoptotic process, and response to reactive oxygen species were upregulated. In contrast, genes involved in intracellular protein traffic, cell cycle, cell adhesion-mediated signaling, cell cycle control, response to reactive oxygen species, and apoptotic process were downregulated under high glucose-treated RNAKT-15 cells.
2015-12-21 | GSE76189 | GEO
Project description:Objective: Transcriptional complex activity drives the development and function of pancreatic islet cells to allow for proper glucose regulation. Our prior work highlighted that the LIM-homeodomain transcription factor (TF), Islet-1 (Isl1), and its interacting co-regulator, Ldb1, are vital effectors of developing and adult β-cells. We further found that a member of the Single Stranded DNA-Binding Protein (SSBP) co-regulator family, SSBP3, interacts with Isl1 and Ldb1 in β-cells and primary islets (mouse and human) to impact β-cell target genes MafA and Glp1R. Members of the SSBP family stabilize TF complexes by binding directly to Ldb1 and protecting the complex from ubiquitin-mediated turnover. In this study, we hypothesized that SSBP3 would have critical roles in pancreatic islet cell development and function in vivo, similar to the Isl1::Ldb1 complex. Methods: We first generated a novel SSBP3 LoxP allele mouse line, where Cre-mediated recombination imparts a predicted early protein termination. We bred this mouse to constitutive Cre lines (Pdx1- and Pax6-driven) to recombine of SSBP3 in the developing pancreas and islet (SSBP3DeltaPanc and SSBP3DeltaIslet), respectively. We assessed glucose tolerance and used immunofluorescence to detect changes in islet cell abundance and markers of β-cell identity and function. Using an inducible Cre system we also deleted SSBP3 in the adult β-cell, a model termed SSBP3Deltaβ-cell. We measured glucose tolerance as well as glucose-stimulated insulin secretion (GSIS), both in vivo and in isolated islets in vitro. Using islets from control and SSBP3Deltaβ-cell we conducted RNA-Seq and compared our results to published datasets for similar β-cell specific Ldb1 and Isl1 knockouts to identify commonly regulated target genes. Results: SSBP3DeltaPanc and SSBP3DeltaIslet neonates present with hyperglycemia. SSBP3DeltaIslet mice are glucose intolerant by P21 and exhibit a reduction of β-cell maturity markers MafA, Pdx1, and UCN3. We observe disruptions in islet cell architecture with an increase in glucagon+ α-cells and ghrelin+ ε-cells at P10. Inducible loss of β-cell SSBP3 in SSBP3Deltaβ-cell causes hyperglycemia, glucose intolerance, and reduced GSIS. Transcriptomic analysis of 14-week SSBP3Deltaβ-cell islets revealed a decrease in β-cell function gene expression (Ins, MafA, Ucn3), increased stress and dedifferentiation markers (Neurogenin-3, Aldh1a3, Gastrin), and shared differentially expressed genes between SSBP3, Ldb1, and Isl1 in adult β-cells. Conclusions: SSBP3 drives proper islet development and identity, where its loss causes altered islet-cell abundance and glucose regulatory function. β-cell SSBP3 is required for GSIS and glucose homeostasis, at least partially through shared regulation of Ldb1 and Isl1 target genes.
2023-08-16 | GSE232750 | GEO
Project description:Recent studies have uncovered thousands of long non-coding RNAs (lncRNAs) in human pancreatic β cells. β cell lncRNAs are often cell type specific and exhibit dynamic regulation during differentiation or upon changing glucose concentrations. Although these features hint at a role of lncRNAs in β cell gene regulation and diabetes, the function of β cell lncRNAs remains largely unknown. In this study, we investigated the function of β cell-specific lncRNAs and transcription factors using transcript knockdowns and co-expression network analysis. This revealed lncRNAs that function in concert with transcription factors to regulate β cell-specific transcriptional networks. We further demonstrate that the lncRNA PLUTO affects local 3D chromatin structure and transcription of PDX1, encoding a key β cell transcription factor, and that both PLUTO and PDX1 are downregulated in islets from donors with type 2 diabetes or impaired glucose tolerance. These results implicate lncRNAs in the regulation of β cell-specific transcription factor networks.
| EGAS00001002865 | EGA
Project description:Background: Survival and function of insulin-secreting pancreatic β-cells are markedly altered by changes in nutrient availability. In vitro, culture in 10 rather than 2mM glucose improves rodent β-cell survival and function whereas glucose concentrations above 10mM are deleterious. Aim-Method: To identify the mechanisms of such β-cell plasticity, we tested the effects of a 18h culture at 2, 5, 10 and 30mM glucose on the transcriptome of rat islets precultured for 1 week at 10mM glucose (Affymetrix Rat 230.2 arrays). Results: Culture in either 2-5mM or 30mM instead of 10mM glucose markedly impaired β-cell function without affecting islet cell survival. Of ~16000 probe sets reliably detected in islets, ~5000 were significantly regulated at least 1.4-fold by glucose. Analysis of these probe sets with GeneCluster software identified 10 mRNA profiles with unidirectional up- or down-regulation between 2 and 10, 2 and 30, 5 and 10, 5 and 30 or 10 and 30 mM glucose, and 8 complex V-shaped or inverse V-shaped profiles with a nadir or peak level of expression in 5 or 10mM glucose. Analysis of genes belonging to these various clusters with Onto-express and GenMapp software revealed several signaling and metabolic pathways that may contribute to the induction of β-cell dysfunction and apoptosis after culture in low or high vs. intermediate glucose concentration. Conclusion: We have identified 18 distinct mRNA profiles of glucose-induced changes in islet gene mRNA levels that should help understanding the mechanisms by which glucose affects β-cell survival and function under states of chronic hypo- or hyperglycemia. Keywords: Dose response
2009-01-26 | GSE12817 | GEO
Project description:Loss of functional beta-cell mass is a hallmark of Type 1 and Type 2 diabetes, and methods for restoring these cells are needed. We have previously reported that overexpression of the homeodomain transcription factor Nkx6.1 in rat pancreatic islets induces beta-cell proliferation and enhances glucose-stimulated insulin secretion, but the pathway by which Nkx6.1 activates beta-cell expansion has not been defined. Here we demonstrate that Nkx6.1 induces expression of the Nr4a1 and Nr4a3 orphan nuclear receptors, and that these factors are both necessary and sufficient for Nkx6.1-mediated beta-cell proliferation. Consistent with this finding, global knockout of Nr4a1 results in a decrease in beta-cell area in neonatal and young mice. Overexpression of Nkx6.1 and the Nr4a receptors results in increased expression of key cell cycle inducers E2F1 and cyclin E1. Furthermore, Nkx6.1 and Nr4a receptors induce components of the anaphase-promoting complex, including Ube2c, resulting in degradation of the cell cycle inhibitor p21CIP1. These studies identify a new bipartite pathway for activation of beta-cell proliferation, suggesting several new targets for expansion of functional beta-cell mass. We set up a microarray using primary rat islets that were left untreated or transduced with adenoviruses overexpressing betagal or Nkx6.1 for 48 h.
2014-02-18 | E-GEOD-55077 | biostudies-arrayexpress