Transcriptional alterations in response to insulin and glucagon in the murine liver
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE111407 | GEO | 2018/03/06
REPOSITORIES: GEO
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Project description:Inappropriate glucagon secretion deteriorates glycemic control in type 1 and type 2 diabetes. While insulin is known to regulate glucagon secretion via its receptor in alpha cells, the role of downstream proteins and signaling pathways underlying the actions of insulin are not fully defined. Using in vivo (knockout) and in vitro (knockdown) studies targeting insulin receptor substrate (IRS) proteins, we compared the relative roles of IRS1 versus IRS2 in regulating alpha cell function. Alpha cell-specific IRS1 knock out (alpha IRS1KO) mice exhibit glucose intolerance and inappropriate glucagon suppression during glucose-tolerance tests. In contrast, alpha cell-specific IRS2 knock outs (alpha IRS2KO) manifest normal glucose tolerance and suppression of glucagon secretion after glucose administration. Alpha cell lines with stable knockdown of IRS1 (alpha IRS1KD) are unable to repress glucagon mRNA expression and exhibit reduction in phosphorylation of AKT. However, glucagon mRNA expression was suppressed in response to insulin stimulation in a stable IRS2 knock down alpha cell line (alpha IRS2KD). Alpha IRS1KD cells also display suppressed global protein translation including glucagon, impaired cytoplasmic Ca2+ response and mitochondrial function. These data argue for IRS1 as a dominant regulator of pancreatic alpha cell function.
2021-04-07 | GSE130329 | GEO
Project description:The transition from a fasted to a fed state is associated with extensive transcriptional remodeling in hepatocytes facilitated by hormonal- and nutritional-regulated transcription factors. Here, we use a liver-specific glucocorticoid receptor (GR) knock-out (L-GRKO) model and primary hepatocytes to investigate the temporal expression of GR target genes in response to feeding. Interestingly, in addition to the well described fasting-regulated genes, we identify a subset of hepatic feeding-induced genes that requires GR for full expression, adding new insights to hepatic GR function. The GR-controlled feeding-induced genes include Gck encoding the glucokinase, which is important for hepatic glucose uptake, utilization and storage. We show that insulin and glucocorticoids cooperatively regulate Gck expression in primary hepatocytes in a GR-dependent manner. ChIP-seq experiments suggest direct GR regulation of Gck by GR occupancy of the promoter and two putative regulatory regions near the Gck gene (Gck -1kb and Gck -4.6kb). Enhancer-reporter assays and CRISPRi suggest that the 4.6kb upstream GR binding site is a functional Gck enhancer. L-GRKO blunts preprandial and early postprandial Gck expression and GR disruption ultimately affects early postprandial hepatic glucose uptake, phosphorylation and glycogen storage. Collectively, our study demonstrates how GR is positively involved in the hepatic feeding response exemplified in the direct regulation of the feeding-induced transcription of glucokinase, important for hepatic glucose metabolism.
2021-09-08 | GSE173723 | GEO
Project description:Context: We present a case of a young adult with GCK mutation who had neonatal hypoglycaemia, re-emerging with hypoglycaemia later in life. Mechanistic insight is gained from detailed clinical, cellular and genomic analysis. Conclusion: This case highlights the variable phenotype of GCK mutations. In depth molecular analyses in the islets has revealed possible mechanisms for nesidioblastosis and insulin hypersecretion.
2022-03-12 | GSE193693 | GEO
Project description:Glucagon serves as an important regulatory hormone for regulating blood glucose concentrations with tight feedback control with insulin and glucose. There are critical gaps in our understanding of glucagon kinetics, pancreatic α cell function and intra-islet feedback network that are disrupted in type 1 diabetes. This is important for translational research applications of evolving dual-hormone (insulin+glucagon) closed-loop artificial pancreas algorithms and their usage in type 1 diabetes. Thus, it is important to accurately measure glucagon kinetics in vivo and to develop robust models of glucose-insulin-glucagon interplay that could inform next generation of artificial pancreas algorithms.
2022-06-09 | PXD028715 | Pride
Project description:MafA and MafB transcription factors have been shown to be key regulators of insulin and glucagon transcription. MafB is essential for alpha and beta cell differentiation, as MafB deficient mice produced fewer insulin+ and glucagon+ cells during development, with MafA expressed in remaining insulin+ cells. In contrast, beta cell development was reported to be normal in a total MafA knock out, although the animals developed beta cell dysfunction and diabetes as adults. However, we have found that MafB expression is elevated during development and retained in adult insulin+ cells after conditional removal of MafA in the pancreas. These studies will evaluate the broader significance of these insulin and glucagon regulators in alpha and beta cell development and function. Our efforts will focus on determining if the concerted actions of MafA and MafB factors are significant to beta cell formation, and we specifically plan to: Determine how alpha and beta cell differentiation is affected in MafA/MafB compound mutant mice during pancreas development. cDNA microarray studies (pancchip 6.0) with wild type, MafAKO, MafB-/-, and MafAKOMafB-/- mutant E18.5 pancreata will be performed to comprehensively identify genes controlled by MafA and MafB in developing alpha and beta cells.
2014-11-04 | E-MTAB-3070 | biostudies-arrayexpress
Project description:Insulin-secreting β cells and glucagon-secreting α cells maintain physiological blood glucose levels, and their malfunction drives diabetes development. Using ChIP sequencing and RNA sequencing analysis, we determined the epigenetic and transcriptional landscape of human pancreatic α, β, and exocrine cells. We found that, compared with exocrine and β cells, differentiated α cells exhibited many more genes bivalently marked by the activating H3K4me3 and repressing H3K27me3 histone modifications. This was particularly true for β cell signature genes involved in transcriptional regulation. Remarkably, thousands of these genes were in a monovalent state in β cells, carrying only the activating or repressing mark. Our epigenomic findings suggested that α to β cell reprogramming could be promoted by manipulating the histone methylation signature of human pancreatic islets. Indeed, we show that treatment of cultured pancreatic islets with a histone methyltransferase inhibitor leads to colocalization of both glucagon and insulin and glucagon and insulin promoter factor 1 (PDX1) in human islets and colocalization of both glucagon and insulin in mouse islets. Thus, mammalian pancreatic islet cells display cell-type–specific epigenomic plasticity, suggesting that epigenomic manipulation could provide a path to cell reprogramming and novel cell replacement-based therapies for diabetes.
2013-08-28 | GSE50386 | GEO
Project description:Insulin-secreting β cells and glucagon-secreting α cells maintain physiological blood glucose levels, and their malfunction drives diabetes development. Using ChIP sequencing and RNA sequencing analysis, we determined the epigenetic and transcriptional landscape of human pancreatic α, β, and exocrine cells. We found that, compared with exocrine and β cells, differentiated α cells exhibited many more genes bivalently marked by the activating H3K4me3 and repressing H3K27me3 histone modifications. This was particularly true for β cell signature genes involved in transcriptional regulation. Remarkably, thousands of these genes were in a monovalent state in β cells, carrying only the activating or repressing mark. Our epigenomic findings suggested that α to β cell reprogramming could be promoted by manipulating the histone methylation signature of human pancreatic islets. Indeed, we show that treatment of cultured pancreatic islets with a histone methyltransferase inhibitor leads to colocalization of both glucagon and insulin and glucagon and insulin promoter factor 1 (PDX1) in human islets and colocalization of both glucagon and insulin in mouse islets. Thus, mammalian pancreatic islet cells display cell-type–specific epigenomic plasticity, suggesting that epigenomic manipulation could provide a path to cell reprogramming and novel cell replacement-based therapies for diabetes. Pancreatic islets were collected post-mortem from 6 human donors and subjected to FACS to separate populations of alpha, beta, and exocrine cells. Depending on the availability of resulting material, sorted islet cell populations were used for H3K4me3, H3K27me3 ChIP-seq, or RNA-seq analysis. All ChIP-seq samples have a corresponding input from the same sample.
2013-08-28 | E-GEOD-50386 | biostudies-arrayexpress
Project description:Identified genes deregulated in mouse primary hepatocytes after modulation of expression/activity of FOXA2 and FXR in glucagon or insulin state
2018-08-16 | GSE113549 | GEO
Project description:Glucagon and insulin are counter-regulatory pancreatic hormones that precisely control blood glucose homeostasis1. Type 2 diabetes mellitus (T2DM) is characterized by inappropriately elevated blood glucagon2-5 levels as well as insufficient glucose stimulated insulin secretion (GSIS) by pancreatic ß-cells6. Early in the pathogenesis of T2DM, hyperglucagonemia is observable antecedent to ß-cell dysfunction7-9; and in mice, liver-specific activation of glucagon receptor-dependent signaling results in impaired GSIS10. However, the mechanistic relationship between hyperglucagonemia, hepatic glucagon action, and ß-cell dysfunction remains poorly understood. Here we show that glucagon action stimulates hepatic production of the neuropeptide kisspeptin1, which acts in an endocrine manner on ß-cells to suppress GSIS. In vivo glucagon administration acutely stimulates hepatic kisspeptin1 production, and kisspeptin1 is increased in livers from humans with T2DM and from mouse models of diabetes mellitus. Synthetic kisspeptin1 potently suppresses GSIS in vivo and in vitro from normal isolated islets, which express the kisspeptin1 receptor Kiss1R. Administration of a Kiss1R antagonist in diabetic Leprdb/db mice potently augments GSIS and reduces glycemia. Our observations indicate in the pathogenesis of T2DM an endocrine mechanism sequentially linking hyperglucagonemia via hepatic kisspeptin1 production to impaired insulin secretion. In addition, our findings suggest Kiss1R antagonism as a therapeutic avenue to improve ß-cell function in T2DM. Total RNA from L-Δprkar1a KO mice compared to control D-glucose mice
2014-04-01 | E-GEOD-48815 | biostudies-arrayexpress
Project description:Diabetes is a disorder characterized by loss of beta cell mass and/or beta cell function, leading to deficiency of insulin relative to metabolic need. To determine whether stem cell derived-beta cells faithfully reflect the phenotypes of a diabetic subject, we generated induced pluripotent stem cells from diabetic subjects (MODY2) with heterozygous loss-of-function of the gene encoding glucokinase (GCK). These stem cells differentiated into beta cells with an efficiency comparable to controls, and expressed markers of mature beta cells, urocotin-3 and zinc transporter 8 upon transplantation into mice. While insulin secretion in response to arginine or other secretagogues was identical to cells from healthy controls, GCK mutant beta cells required higher glucose levels to stimulate insulin secretion. Importantly this glucose-specific phenotype was fully reverted upon gene sequence correction by homologous recombination. Our results demonstrate that stem cell-derived beta cells reflect beta cell-autonomous phenotypes of MODY2 subjects, providing a platform for mechanistic analysis of specific genotypes on beta cell function. Induced pluripotent stem cells with munations in the glucokinase gene were differentiationed into pancreas cells using published protocol (D'Amour et al, 2006) with certain modifications. 1 million cells(fibroblast or stem cells or differentiated pancreatic cells) was used for RNA extraction and labeling using the Illumina total prep RNA amplification kit.
2013-04-05 | E-GEOD-45777 | biostudies-arrayexpress