Chromatin reorganization drives expression of functional maturation genes in senescent pancreatic beta cells (Series2 - chromatin sccessibility, ATAC-seq)
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE207818 | GEO | 2024/06/26
REPOSITORIES: GEO
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Project description:Using a unique model of cultured human beta cell senescence we show that chromatin reorganization leads to activation of enhancers regulating functional maturation genes, concomitantly with acquisition of glucose-stimulated insulin secretion capacity. Interferon-response genes are elevated in senescent beta cells, but cytokine-encoding senescence-associated secretory phenotype (SASP) genes are not. Human beta cell senescence thus involves chromatin-driven upregulation of a functional maturation program and of interferon-stimulated genes, changes that could increase both insulin secretion and immune reactivity.
2024-06-26 | GSE207825 | GEO
Project description:Using a unique model of cultured human beta cell senescence we show that chromatin reorganization leads to activation of enhancers regulating functional maturation genes, concomitantly with acquisition of glucose-stimulated insulin secretion capacity. Interferon-response genes are elevated in senescent beta cells, but cytokine-encoding senescence-associated secretory phenotype (SASP) genes are not. Human beta cell senescence thus involves chromatin-driven upregulation of a functional maturation program and of interferon-stimulated genes, changes that could increase both insulin secretion and immune reactivity.
2024-06-26 | GSE207822 | GEO
Project description:Using a unique model of cultured human beta cell senescence we show that chromatin reorganization leads to activation of enhancers regulating functional maturation genes, concomitantly with acquisition of glucose-stimulated insulin secretion capacity. Interferon-response genes are elevated in senescent beta cells, but cytokine-encoding senescence-associated secretory phenotype (SASP) genes are not. Human beta cell senescence thus involves chromatin-driven upregulation of a functional maturation program and of interferon-stimulated genes, changes that could increase both insulin secretion and immune reactivity.
2024-06-26 | GSE207816 | GEO
Project description:Stem cell-derived β (SC-β) cells are an emerging regenerative therapy to compensate for loss of functional β cell mass in diabetes. Glucose-stimulated insulin secretion in SC-β cells is variable in vitro but stabilizes after transplantation and maturation under the kidney capsule of mice. We identified mechanisms correlated with functional maturation using RNA-sequencing and co-expression network analysis. In vivo maturation enhanced glucose-stimulated but not basal insulin secretion, up-regulated β cell hormones IAPP and ADCYAP1, increased expression of maturation markers MAFA, UCN3, and SIX2, and resolved endocrine identity of incompletely specified polyhormonal cells produced during differentiation. Transplantation promoted calcium signalling, induced exocytotic machinery supporting hormone secretion and improved stimulus-secretion coupling that fine-tunes insulin secretion. Growth hormone signalling emerged as candidate driver of in vivo maturation and was confirmed in vitro. Also, a large co-expression module correlated with HbA1c and was enriched in genes up-regulated during in vivo maturation but down-regulated in hyperglycaemic and palmitate stress conditions, suggesting that transcriptional maturation of SC-β cells in vivo mirrors processes lost in diabetic β cells.
2019-08-19 | GSE135944 | GEO
Project description:Pancreatic beta-cells are highly specialized cells that produce and release insulin in response to nutrients, hormones and neurotransmitters. Glucose-induced insulin secretion, a unique feature of fully differentiated beta-cells, is only acquired after birth and is preceded by a phase of intense beta-cell proliferation. These events occurring in the neonatal period are critical for the establishment of an appropriate functional beta-cell mass covering the insulin needs throughout life. However, key regulators of gene expression and cis-regulatory elements involved in the cellular reprogramming along maturation remain to be elucidated. This project addresses this issue by using ATAC-seq (Assay for Transposase-Accessible Chromatin with high throughput sequencing) permitting a fine genome-wide mapping of chromatin accessibility. This approach is used to compare open chromatin regions in newborn and adult rat beta-cells. We obtained a genome-wide picture of chromatin accessible sites (100000) among which 20% were differentially accessible during maturation. Nearly 60% of these sites were in the proximity of significantly differentially expressed genes. An analysis of transcription factor binding sites revealed key known and unforeseen transcription factors which could explain these changes. We validated a transcriptional repressor named SCRT1, that depicted a significant effect on beta-cell proliferation and targeted several genes implicated in the acquisition of glucose-stimulated insulin secretion function. Thus, we were able to find several known and unforeseen key transcriptional regulators acting at cis-regulatory sites and promoters which depicted a differential accessibility and induced differential gene expression along maturation. These findings could be of interest to induce maturation of surrogate insulin-producing cells.
2020-05-01 | GSE130651 | GEO
Project description:Insulin-dependent diabetes is a complex multifactorial disorder characterized by loss or dysfunction of β-cells. Pancreatic β-cells differ in size, glucose responsiveness, insulin secretion and precursor cell potential, thus understanding the mechanisms underlying this functional heterogeneity might allow novel regenerative approaches. Here we discovered Flattop (Fltp) as a biomarker that distinguishes proliferative from mature β-cell subpopulations with distinct molecular, physiological and ultrastructural features. Genetic lineage tracing revealed that these β-cell subpopulations react differentially to environmental changes. Upon insulin resistance Fltp- β-cells undergo compensatory proliferation, whereas Fltp-lineage+ β-cells account for islet cell hypertrophy commonly associated with cytotoxic stress. The expression of the Wnt/planar cell polarity (PCP) effector gene Fltp increases when naïve β-cells cluster together to form polarized and mature three-dimensional (3D) islet mini-organs. We show that 3D architecture and Wnt/PCP ligands are sufficient to trigger mouse and human β-cell maturation. Finally, we show that Fltp is not necessary for β-cell development, proliferation, or maturation, but is required for proper glucose-stimulated insulin secretion in mature β-cells. We conclude that 3D architecture and Wnt/PCP signaling underlie functional β-cell heterogeneity and induce β-cell maturation. The identification of Fltp as a biomarker for mature β-cells establish novel molecular underpinnings of β-cells and enable targeting of subpopulations for the regeneration of functional β-cell mass in diabetic patients.
2016-06-02 | GSE68853 | GEO
Project description:The pancreas plays a critical role in maintaining glucose homeostasis through the secretion of hormones from the islets of Langerhans. Glucose-stimulated insulin secretion (GSIS) by the pancreatic beta-cell is the main mechanism for reducing elevated plasma glucose.
Here we present a systematic modeling workflow for the development of kinetic pathway models using the Systems Biology Markup Language (SBML). An important factor was the reproducibility and exchangeability of the model, which allowed the use of various existing tools.
The workflow was applied to construct a novel data-driven kinetic model of GSIS in the pancreatic beta-cell based on experimental and clinical data from 39 studies spanning 50 years of pancreatic, islet, and beta-cell research in humans, rats, mice, and cell lines. The model consists of detailed glycolysis and phenomenological equations for insulin secretion coupled to cellular energy state, ATP dynamics and (ATP/ADP ratio).
Key findings of our work are that in GSIS there is a glucose-dependent increase in almost all intermediates of glycolysis. This increase in glycolytic metabolites is accompanied by an increase in energy metabolites, especially ATP and NADH. One of the few decreasing metabolites is ADP, which, in combination with the increase in ATP, results in a large increase in ATP/ADP ratios in the beta-cell with increasing glucose. Insulin secretion is dependent on ATP/ADP, resulting in glucose-stimulated insulin secretion.
2024-01-18 | MODEL2401110001 | BioModels
Project description:Pancreatic β cell dysfunction greatly contributes to the pathogenesis of type 2 diabetes. MiR-21 has been shown to be induced in the islets of glucose intolerant patients and type 2 diabetic mice. However, the role of miR-21 in the regulation of pancreatic β cell function remains largely elusive. In the current study, we studied the pathway by which miR-21 regulates glucose-stimulated insulin secretion utilizing mice lacking miR-21 in their β cells (miR-21βKO). We found that miR-21βKO mice developed glucose intolerance due to impaired glucose-stimulated insulin secretion. Mechanistic studies revealed that miR-21 enhances glucose uptake and subsequently promotes insulin secretion by up-regulating Glut2 expression in a miR-21-Pdcd4-AP-1 dependent pathway. Over-expression of Glut2 in knockout islets resulted in rescue of the impaired glucose-stimulated insulin secretion. Furthermore, we demonstrated that delivery of miR-21 into the pancreas of type 2 diabetic db/db mice is able to promote Glut2 expression and significantly reduce blood glucose level. Taking together, our results reveal that miR-21 in islet β cell promotes insulin secretion and support a role for miR-21 in the adaptation of pancreatic β cell function in type 2 diabetes.
2022-05-16 | GSE191194 | GEO
Project description:Pancreatic beta-cells are specialized for coupling glucose metabolism to insulin peptide production and secretion. Acute glucose exposure robustly and coordinately increases translation of proinsulin and proteins required for secretion of mature insulin peptide. By contrast, chronically elevated glucose levels that occur during diabetes impair beta-cell insulin secretion and have been shown experimentally to suppress insulin translation. Whether translation of other genes critical for insulin secretion are similarly downregulated by chronic high glucose is unknown. Here, we used high-throughput ribosome profiling and nascent proteomics in MIN6 insulinoma cells to elucidate the genome-wide impact of sustained high glucose on beta-cell mRNA translation. Prior to induction of ER stress or suppression of global translation, sustained high glucose suppressed glucose-stimulated insulin secretion and downregulated translation of not only insulin, but also of mRNAs related to insulin secretory granule formation, exocytosis, and metabolism-coupled insulin secretion. Translation of these mRNAs was also downregulated in primary rat and human islets following ex-vivo incubation with sustained high glucose and in an in vivo model of chronic mild hyperglycemia. Furthermore, translational downregulation decreased cellular abundance of these proteins. Our study uncovered a translational regulatory circuit during beta-cell glucose toxicity that impairs expression of proteins with critical roles in beta-cell function.
2023-12-01 | GSE248349 | GEO
Project description:Objective: Histone deacetylases are epigenetic regulators known to control gene transcription in various tissues. A member of this family, histone deacetylase 3 (HDAC3), has been shown to regulate metabolic genes. Cell culture studies with HDAC-specific inhibitors and siRNA suggest that HDAC3 plays a role in pancreatic β-cell function, but a recent genetic study in mice has been contradictory. Here we address the functional role of HDAC3 in β-cells of adult mice. Methods: An HDAC3 β-cell specific knockout was generated in adult MIP-CreERT transgenic mice using the Cre-loxP system. Induction of HDAC3 deletion was initiated at 8 weeks of age with administration of tamoxifen in corn oil (2 mg/day for 5 days). Mice were assayed for glucose tolerance, glucose-stimulated insulin secretion, and islet function 2 weeks after induction of the knockout. Transcriptional functions of HDAC3 were assessed by ChIP-seq as well as RNA-seq comparing control and -cell knockout islets. Results: HDAC3 β-cell specific knockout (HDAC3βKO) did not increase total pancreatic insulin content or β-cell mass. However, HDAC3βKO mice demonstrated markedly improved glucose tolerance. This improved glucose metabolism coincided with increased basal and glucose-stimulated insulin secretion in vivo as well as in isolated islets. Cistromic and transcriptomic analyses of pancreatic islets revealed that HDAC3 regulates multiple genes that contribute to glucose-stimulated insulin secretion. Conclusions: HDAC3 plays an important role in regulating insulin secretion in vivo and therapeutic intervention may improve glucose homeostasis.
2016-11-26 | GSE90531 | GEO