Type 2 diabetes susceptibility gene GRK5 regulates physiological pancreatic β-cell proliferation via phosphorylation of HDAC5
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE221716 | GEO | 2023/07/31
REPOSITORIES: GEO
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Project description:The inability of the beta-cell to meet the demand for insulin brought about by insulin resistance leads to type 2 diabetes. In adults, beta-cell replication is one of the mechanisms thought to cause the expansion of beta-cell mass. Efforts to treat diabetes require knowledge of the pathways that drive facultative beta-cell proliferation in vivo. A robust physiological stimulus of beta-cell expansion is pregnancy, and identifying the mechanisms underlying this stimulus may provide therapeutic leads for the treatment of type 2 diabetes. The peak in beta-cell proliferation during pregnancy occurs on day 14.5 of gestation in mice. Using advanced genomic approaches, we globally characterize the gene expression signature of pancreatic islets on day 14.5 of gestation during pregnancy. We identify a total of 1,907 genes as differentially expressed in the islet during pregnancy. We demonstrate that the islet's ability to compensate for relative insulin deficiency during metabolic stress is associated with the induction of both proliferative and survival pathways. A comparison of the genes induced in three different models of islet expansion suggests that diverse mechanisms can be recruited to expand islet mass. The identification of many novel genes involved in islet expansion during pregnancy provides an important resource for diabetes researchers to further investigate how these factors contribute to the maintenance of not only islet mass, but ultimately beta-cell mass.
2010-06-26 | E-MTAB-120 | biostudies-arrayexpress
Project description:GLP-1 analogues, such as exendin-4, preserve functional β-cell mass in various model systems and are revolutionising management of type 2 diabetes. Yet, comparatively little is known about effectiveness in the face of severe β-cell depletion. Moreover, direct and sequential effects of exendin-4 on islet-specific gene expression over time in vivo are not well characterised. To address these issues and others, we have examined the time-dependent effects of exendin-4 treatment on β-cell mass regulation alongside accompanying changes in islet gene expression in vivo. Context-dependent actions were assessed by comparing effects on normal islets and also following massive toxigenetic β-cell ablation in pIns-MYCERTAM transgenic mice in vivo. Despite over 90% loss of β-cell mass, exendin-4 treatment normalised blood glucose and insulin levels in hyperglycaemic mice, though benefits rapidly waned on withdrawal of treatment. As exendin-4 did not arrest the decline in β-cell mass or turnover in this study, we could directly isolate effects on function of surviving β-cells. Improved glucose homeostasis was associated with dynamic changes in multiple islet genes and pathways in vivo favouring glucose-stimulated insulin secretion, such as Irs2, Pdx1, Sox4, glucokinase, and glycolysis pathway. Several key growth pathways and epigenetic regulators were also differentially expressed. Thus, even in the face of extensive β-cell loss exendin-4 can markedly improve hyperglycaemia by differential gene expression in surviving islet cells.
2014-04-11 | GSE37936 | GEO
Project description:AIMS/HYPOTHESIS: Manoeuvres aimed at increasing beta cell mass have been proposed as regenerative medicine strategies for diabetes treatment. Raf-1 kinase inhibitor protein 1 (RKIP1) is a common regulatory node of the mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) pathways and therefore may be involved in regulation of beta cell homeostasis. The aim of this study was to investigate the involvement of RKIP1 in the control of beta cell mass and function. METHODS: Rkip1 (also known as Pebp1) knockout (Rkip1 (-/-)) mice were characterised in terms of pancreatic and glucose homeostasis, including morphological and functional analysis. Glucose tolerance and insulin sensitivity were examined, followed by assessment of glucose-induced insulin secretion in isolated islets and beta cell mass quantification through morphometry. Further characterisation included determination of endocrine and exocrine proliferation, apoptosis, MAPK activation and whole genome gene expression assays. Capacity to reverse a diabetic phenotype was assessed in adult Rkip1 (-/-) mice after streptozotocin treatment. RESULTS: Rkip1 (-/-) mice exhibit a moderately larger pancreas and increased beta cell mass and pancreatic insulin content, which correlate with an overall improvement in whole body glucose tolerance. This phenotype is established in young postnatal stages and involves enhanced cellular proliferation without significant alterations in cell death. Importantly, adult Rkip1 (-/-) mice exhibit rapid reversal of streptozotocin-induced diabetes compared with control mice. CONCLUSIONS/INTERPRETATION: These data implicate RKIP1 in the regulation of pancreatic growth and beta cell expansion, thus revealing RKIP1 as a potential pharmacological target to promote beta cell regeneration. Pancreatic gene expression of Rkip-1 (Raf kinase inhibitor 1) knockout (KO) and wild type (WT) mice, including three biological replicates in each group.
2012-11-19 | E-GEOD-31150 | biostudies-arrayexpress
Project description:Insulin resistance is necessary but not sufficient for the development of type 2 diabetes. Diabetes results when pancreatic beta-cells fail to compensate for insulin resistance by increasing insulin production through an expansion of beta-cell mass or increased insulin secretion. Communication between insulin target tissues and beta-cells may initiate this compensatory response. Correlated changes in gene expression between tissues can provide evidence for such intercellular communication. We profiled gene expression in six tissues of mice from an obesity-induced diabetes-resistant and a diabetes-susceptible strain before and after the onset of diabetes. We studied the correlation structure of mRNA abundance and identified 105 co-expression gene modules. We provide an interactive gene network model showing the correlation structure between the expression modules within and among the six tissues. This resource also provides a searchable database of gene expression profiles for all genes in six tissues in lean and obese diabetes-resistant and diabetes-susceptible mice, at 4 and 10 weeks of age. A cell cycle regulatory module in islets predicts diabetes susceptibility. The module predicts islet replication; we found a strong correlation between ^2 H_2 O incorporation into islet DNA /in vivo/ and the expression pattern of the cell cycle module. This pattern is highly correlated with that of several individual genes in insulin target tissues, including IGF2, which has been shown to promote beta-cell proliferation, suggesting that these genes may provide a link between insulin resistance and beta-cell proliferation. Keywords: time course, mouse strain comparison, effect of obesity, Type 2 diabetes is a disorder that involves an increased demand for insulin brought about by insulin resistance, together with a failure to compensate with sufficient insulin production. Although Insulin resistance occurs in most obese individuals, diabetes is generally forestalled through compensation with increased insulin. This increase in insulin occurs through an expansion of beta-cell mass and/or increased insulin secretion by individual beta-cells. Failure to compensate for insulin resistance leads to type 2 diabetes. One way to understand the pathophysiology of diabetes is to examine the coordinate changes in gene expression that occur in insulin-responsive tissues and pancreatic islets in obese animals that either compensate for insulin resistance or progress to type 2 diabetes. In each case, there are groups of genes that undergo changes in expression in a highly correlated fashion. By identifying groups of correlated transcripts (gene expression modules) during the compensation and development of diabetes, we can gain insight into potential pathways and regulatory networks in obesity-induced diabetes. We study two strains of mice that differ in obesity-induced diabetes susceptibility. In this study, we surveyed gene expression in six tissues of lean and obese C57BL/6 (B6) and BTBR mice aged 4 wks and 10 wks. B6 mice remain essentially non-diabetic at all ages, irrespective of obesity. When obese, BTBR mice become severely diabetic by 10 weeks of age. By analyzing the correlation structure of the genes under three contrast conditions, obesity, strain, and age, we identified gene expression modules associated with the onset of diabetes and provide an interactive co-expression network model of type 2 diabetes. We found a key module that is comprised of cell cycle regulatory genes. In the islet, the expression profile of these transcripts accurately predicts diabetes and is highly correlated with islet cell proliferation.
2008-03-14 | E-GEOD-10785 | biostudies-arrayexpress
Project description:Relative beta cell deficit and increased beta cell apoptosis are hallmarks of type 2 diabetes (T2D). The Insulin/Insulin Growth Factor (Igf) signaling pathway is an established regulator of beta cell survival and is found downregulated in human T2D islets. The Insulin Receptor Substrate 2 (Irs2) plays a central role in the coordination of this pathway in beta cells. Thus, Irs2 knockout mice (Irs2 -/-) exhibit increased beta cell apoptosis that leads to a progressive decline of beta cell mass and hyperglycaemia. In this study, we sought to determine whether the anti-diabetic compound sodium tungstate could prevent the onset of diabetes in Irs2 -/- mice. Oral administration of tungstate resulted in an overall improvement in whole-body glucose tolerance in Irs2 -/- mice which correlated with increased beta cell mass. Enhanced beta cell mass was due to a dramatic reduction of beta cell apoptosis without changes in proliferation. Whole genome gene profiling analysis of islets isolated from treated Irs2 -/- mice confirmed a broad impact of tungstate on cell death pathways. Mechanistically, tungstate induced Erk1/2 phosphorylation in islets in vitro and, in agreement, treated Irs2 -/- islets exhibited increased basal Erk1/2 phosphorylation. Tungstate also downregulated expression of apoptosis-related genes in Irs2-/- islets in vitro, uncovering a direct effect of this compound in islets. All together, our data demonstrate that tungstate can restore beta cell mass and glucose homeostasis in a context of deficient Insulin/Igf signaling. This study underscores the importance of developing strategies specifically designed to arrest beta cell apoptosis as a means to prevent progressive beta cell failure in diabetes. 10-week old WT and Irs2 -/- mice were randomly divided into two treatment group, in a total of 4 experimental groups. For 21 days one group received distilled water as drinking water (untreated group) whilst the other received ad libitum a solution of 2mg/ml of sodium tungstate in distilled water (treated group). For each experimental group 2 independent samples were analysed, in a total of 8 samples.
2014-01-19 | E-GEOD-43620 | biostudies-arrayexpress
Project description:The progression towards type 2 diabetes depends on the success of the allostatic response of the pancreatic beta cells to synthesise and secrete enough insulin to compensate for insulin resistance. The endocrine pancreas is a plastic tissue able to expand or regress in response to the requirements imposed by physio and pathological states such as pregnancy, obesity or ageing. The mechanisms, mediating beta cell mass expansion in these scenarios are not well defined. We have recently showed that beta cell mass failed to expand in ob/ob mice with genetic ablation of PPARγ2, a mouse model known as the POKO mouse. This phenotype contrasted with the appropriate expansion of the beta cell mass observed in their obese littermate ob/ob mice. Here we investigate PPAR gamma dependent transcriptional responses occurring during early stages of the adaptation of beta cells to insulin resistance. As it could be expected we have identified genes known to regulate proliferation and survival signals of the beta cells. Moreover we have also identified new pathways induced in ob/ob islets that fail to do so in POKO islets. Our data suggest that the expansion of beta cell mass observed in ob/ob islets is associated with activation of immune response and is missing in POKO islets. Other PPARγ dependent differentially regulated pathways include cholesterol biosynthesis, apoptosis through TGF-β signaling and decreased oxidative phosphorylation. In this study, we used gene expression arrays to investigate differences between four experimental classes by pairs
2012-01-16 | E-GEOD-33647 | biostudies-arrayexpress
Project description:Diabetes mellitus results from an inadequately functioning beta-cell mass. In the adult pancreas, beta-cell mass is dynamic, increasing to meet metabolic demands and decreasing with metabolic or injury insults. Exendin-4 (Ex-4) is a glucagon-like peptide-1 receptor agonist that augments beta-cell mass by increasing beta-cell neogenesis and proliferation and by reducing apoptosis. We utilized a cDNA microarray approach to identify genes that are differentially regulated during islet growth after Ex-4 treatment or a partial pancreatectomy (Ppx). Mice underwent 50% Ppx or sham operation and received Ex-4 or vehicle every 24 hours. cDNA prepared from total pancreatic RNA isolated at 12, 24 and 48 hrs after surgery was hybridized to the PancChip 4.0 microarray.
2005-12-01 | E-CBIL-5 | biostudies-arrayexpress
Project description:MTA1, SOX4, EZH2 and TGF-β are all potent inducers of epithelial-mesenchymal transition (EMT) in cancer; however, the signaling relationship among these molecules in EMT is poorly understood. Here, we investigated the function of MTA1 in cancer cells and demonstrated that MTA1 overexpression efficiently activates EMT. This activation resulted in a significant increase in the migratory and invasive properties of three different cancer cell lines through a common mechanism involving SOX4 activation, screened from a gene expression profiling analysis. We showed that both SOX4 and MTA1 are induced by TGF-β and both are indispensable for TGF-β-mediated EMT. Further investigation identified that MTA1 acts upstream of SOX4 in the TGF-β pathway, emphasizing a TGF-β-MTA1-SOX4 signaling axis in EMT induction. The histone methyltransferase EZH2, a component of the polycomb (PcG) repressive complex 2 (PRC2), was identified as a critical responsive gene of the TGF-β-MTA1-SOX4 signaling in three different epithelial cancer cell lines, suggesting that this signaling acts broadly in cancer cells in vitro. The MTA1-SOX4-EZH2 signaling cascade was further verified in TCGA pan-cancer patient samples and in a colon cancer cDNA microarray, and activation of genes in this signaling pathway predicted an unfavorable prognosis in colon cancer patients. Collectively, our data uncover a SOX4-dependent EMT-inducing mechanism underlying MTA1-driven cancer metastasis and suggest a widespread TGF-β-MTA1-SOX4-EZH2 signaling axis that drives EMT in various cancers. We propose that this signaling may be used as a common therapeutic target to control epithelial cancer metastasis. We used microarrays to detect MTA1-regulated genes in cancer cells.
2019-10-27 | GSE139429 | GEO
Project description:Expanding beta cell mass is a critical goal in the fight against diabetes. CDK4, an extensively characterized cell cycle activator, is required to establish and maintain beta cell number. Beta cell failure in the IRS2-deletion mouse type 2 diabetes model is in part due to loss of CDK4 regulator Cyclin D2. We set out to determine whether replacement of endogenous CDK4 with the inhibitor-resistant mutant CDK4-R24C rescued the loss of beta cell mass in Irs2-deficient mice. Surprisingly, not only beta cell mass but also beta cell dedifferentiation was effectively rescued, despite no improvement in whole body insulin sensitivity. Ex vivo studies in primary islet cells revealed a novel mechanism in which CDK4 intervened downstream in the insulin signaling pathway to prevent FOXO1-mediated transcriptional repression of critical beta cell transcription factor Pdx1. FOXO1 inhibition was not related to E2F1 activity, to FOXO1 phosphorylation, or even to FOXO1 subcellular localization, but rather was related to deacetylation and reduced FOXO1 abundance. Taken together, these results demonstrate a novel differentiation-promoting activity of the classical cell cycle activator CDK4 and support the concept that beta cell mass can be expanded without compromising function.
2023-07-31 | GSE235129 | GEO
Project description:Relative beta cell deficit and increased beta cell apoptosis are hallmarks of type 2 diabetes (T2D). The Insulin/Insulin Growth Factor (Igf) signaling pathway is an established regulator of beta cell survival and is found downregulated in human T2D islets. The Insulin Receptor Substrate 2 (Irs2) plays a central role in the coordination of this pathway in beta cells. Thus, Irs2 knockout mice (Irs2 -/-) exhibit increased beta cell apoptosis that leads to a progressive decline of beta cell mass and hyperglycaemia. In this study, we sought to determine whether the anti-diabetic compound sodium tungstate could prevent the onset of diabetes in Irs2 -/- mice. Oral administration of tungstate resulted in an overall improvement in whole-body glucose tolerance in Irs2 -/- mice which correlated with increased beta cell mass. Enhanced beta cell mass was due to a dramatic reduction of beta cell apoptosis without changes in proliferation. Whole genome gene profiling analysis of islets isolated from treated Irs2 -/- mice confirmed a broad impact of tungstate on cell death pathways. Mechanistically, tungstate induced Erk1/2 phosphorylation in islets in vitro and, in agreement, treated Irs2 -/- islets exhibited increased basal Erk1/2 phosphorylation. Tungstate also downregulated expression of apoptosis-related genes in Irs2-/- islets in vitro, uncovering a direct effect of this compound in islets. All together, our data demonstrate that tungstate can restore beta cell mass and glucose homeostasis in a context of deficient Insulin/Igf signaling. This study underscores the importance of developing strategies specifically designed to arrest beta cell apoptosis as a means to prevent progressive beta cell failure in diabetes.
2014-01-19 | GSE43620 | GEO