Checkpoint Kinase 2 Controls Insulin Secretion and Glucose Homeostasis
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE239335 | GEO | 2023/10/25
REPOSITORIES: GEO
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Project description:Objective Notch signaling is re-activated in β cells from obese mice, and is causal to β cell dysfunction. Notch activity is determined in part by expression of transmembrane ligand availability in a neighboring cell. We hypothesized that β cell expression of Jagged1 determines the maladaptive Notch response and resultant β cell dysfunction in obese mice. Methods We assessed expression of Notch pathway components in diet-induced obese (DIO) or leptin receptor-deficient (db/db) mice, and performed single cell RNA sequencing (scRNAseq) in islets from patients with and without type 2 diabetes (T2D). We generated and performed glucose tolerance testing in inducible, β cell-specific Jagged1 gain-of- and loss-of-function mice. We also tested effects of monoclonal neutralizing antibodies to Jagged1 in glucose-stimulated insulin secretion (GSIS) assays in isolated islets. Results Jag1 was the only Notch ligand that tracked with increased Notch activity in DIO and db/db mice. Consistently, JAG1 tracked with Notch activity in metabolically inflexible β cells enriched in patients with T2D. Neutralizing antibodies to block Jagged1 in islets isolated from DIO and db/db mice potentiated GSIS ex vivo. To demonstrate if β cell Jagged1 is sufficient to cause glucose tolerance in vivo, we generated inducible β cell-specific Jag1 transgenic mice (β-Jag1TG), which showed impaired glucose intolerance due to reduced GSIS. However, β cell-specific Jagged1 loss-of-function (β-Jag1KO) did not protect against HFD-induced insulin secretory defects or glucose intolerance. Conclusions Jagged1 is increased in islets from obese mice and in patients with T2D, and neutralizing Jagged1 antibodies lead to improved GSIS, suggesting that inhibition of Jagged1-Notch signaling may have therapeutic benefit. However, genetic loss-of-function experiments suggest that β cells are not a likely source of the Jagged1 signal.
2024-02-23 | GSE249170 | 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:Altered islet architecture is associated with β cell dysfunction and Type 2 Diabetes (T2D) progression, but molecular effectors of islet spatial organization remain mostly unknown. Although Notch signaling is known to regulate pancreatic development, we observed “re-activated” β cell Notch activity in obese mouse models. To test the repercussions and reversibility of Notch effects, we generated doxycycline-dependent, β cell-specific Notch gain-of-function mice. As predicted, we found that Notch activation in post-natal β cells impaired glucose stimulated insulin secretion (GSIS) and glucose intolerance, but we observed a surprising remnant glucose intolerance after doxycycline withdrawal and cessation of Notch activity, associated with a marked disruption of normal islet architecture. Transcriptomic screening of Notch-active islets revealed increased Ephrin signaling. Commensurately, exposure to Ephrin ligands increased β cell repulsion, and impaired murine and human pseudo-islet formation. Consistent with our mouse data, Notch and Ephrin signaling are increased in metabolically-inflexible β cells in patients with T2D. These studies suggest than islet architecture can be permanently altered by β cell Notch/Ephrin signaling during a morphogenetic window in early life.
2022-02-21 | GSE193888 | GEO
Project description:Deterioration of functional islet β-cell mass is the final step in progression to Type 2 diabetes. We previously reported that overexpression of Nkx6.1 in rat islets has the dual effects of enhancing glucose-stimulated insulin secretion (GSIS) and increasing β-cell replication. Here we show that Nkx6.1 strongly upregulates the prohormone VGF in rat islets and that VGF is both necessary and sufficient for Nkx6.1-mediated enhancement of GSIS. Moreover, the VGF-derived peptide TLQP-21 potentiates GSIS in rat and human islets and improves glucose tolerance in vivo. Chronic injection of TLQP-21 in pre-diabetic ZDF rats preserves islet mass and slows diabetes onset. TLQP-21 prevents islet cell apoptosis by a pathway similar to that used by GLP-1, but independent of the GLP-1, GIP, or VIP receptors. Unlike GLP-1, TLQP-21 does not inhibit gastric emptying or increase heart rate. We conclude that a TLQP-21 is a novel agent for enhancing islet β-cell survival and function.
2012-05-10 | GSE37852 | GEO
Project description:Glucose-stimulated insulin secretion (GSIS) is suppressed through α-adrenergic receptor stimulation by catecholamines, epinephrine and norepinephrine, in pancreatic β-cells. Previous work has elucidated a bevy of adrenergic regulatory mechanisms beyond traditional Gi-coupled signaling including regulation of ion channels and interactions with exocytotic machinery. Glucose oxidation may also be an important site for adrenergic regulation of GSIS, but the link between epinephrine and glucose oxidation in β-cells is undefined. Here, we evaluate whether adrenergic stimulation decreases oxidative metabolism in β cells. Oxygen consumption rates were determined for Min6 and isolated rat islets in 20mM glucose complete media, then epinephrine was added at either 0 nM (vehicle control) or 100nM, followed by 10uM yohimbine (a selective Adrα2A antagonist). To identify glucose oxidation as the primary metabolic pathway affected by epinephrine, oxidation of 14C(U)-labeled glucose was determined in Min6 cells with epinephrine or vehicle. Oxygen consumption and glucose oxidation experiments were conducted in the presence of cAMP and insulin secretion blockers, respectively. Proteomics was performed on Min6 cells exposed to epinephrine for 4 hours and compared to controls. Epinephrine, but not vehicle, reduced (P<0.01) oxygen consumption rates in rat islets and Min6 cells to 64 ± 6% and 65 ± 1% of baseline, respectively, and yohimbine restored oxygen consumption to rates not different from baseline. In Min6 cells incubated with epinephrine rates of 14C glucose oxidation were reduced (P<0.01) 66 ± 4% compared to vehicle controls. These results demonstrate that acute epinephrine exposure suppresses glucose oxidation in β cells via the specific adrenergic receptor, Adrα2A, and indicate a new role for adrenergic regulation in GSIS.
2019-11-08 | PXD006330 | Pride
Project description:SHP (small heterodimer partner; NR0B2) belongs to the nuclear hormone receptor superfamily, which regulates numerous developmental and metabolic cellular functions. To study physiological function of SHP, we generated congenic SHP-/- mice on C57Bl/6 background. When the congenic SHP-/- mice were challenged with a western diet (high fat, hgih sucrose, high cholesterol) for 20 weeks, they were resistant to diet induced obesity but severely glucose intolerant compared to wild type control mice. However, their overall peripheral tissue insulin sensitivity was normal when assessed by insulin tolerance test. Next, we examined the glucose stimulated insulin secretion (GSIS) in isolated islets from these animals. Islets from SHP-/- mice showed strongly impaired GSIS especially fed the western diet, which is believed to be a major factor causing the whole body glucose intolerance in SHP-/- mice. Therefore, we explored gene expression in islets using illumina beadchip array to understand mechanisms underneath the impaired GSIS.
2010-02-24 | GSE20518 | GEO
Project description:Deterioration of functional islet β-cell mass is the final step in progression to Type 2 diabetes. We previously reported that overexpression of Nkx6.1 in rat islets has the dual effects of enhancing glucose-stimulated insulin secretion (GSIS) and increasing β-cell replication. Here we show that Nkx6.1 strongly upregulates the prohormone VGF in rat islets and that VGF is both necessary and sufficient for Nkx6.1-mediated enhancement of GSIS. Moreover, the VGF-derived peptide TLQP-21 potentiates GSIS in rat and human islets and improves glucose tolerance in vivo. Chronic injection of TLQP-21 in pre-diabetic ZDF rats preserves islet mass and slows diabetes onset. TLQP-21 prevents islet cell apoptosis by a pathway similar to that used by GLP-1, but independent of the GLP-1, GIP, or VIP receptors. Unlike GLP-1, TLQP-21 does not inhibit gastric emptying or increase heart rate. We conclude that a TLQP-21 is a novel agent for enhancing islet β-cell survival and function. We utilized a “sample x reference” experimental design strategy in which RNA extracted from rat pancreatic islets was hybridized to the microarray slide in the presence of labeled rat reference RNA (RRR, Stratagene, LaJolla, CA). Cultures were treated with adenoviruses expressing either the hamster form of Nkx6.1, the mouse form of Pdx1, or the beta-galactosidase enzyme. 3-5 biological replicates each representing independent islet isolations were used for microarray analysis. Briefly, five hundred nanograms of total RNA were used for gene expression profiling following reverse transcription and T-7 polymerase-mediated amplification/labeling with Cyanine-5. Labeled subject cRNA was co-hybridized to Operon rat 27K oligonucleotide arrays with equimolar amounts of Cyanine-3 labeled RRR. Slides were hybridized, washed, and scanned on a Gene Pix 5000 microarray scanner.
2012-05-09 | E-GEOD-37852 | biostudies-arrayexpress
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:Butyrate, a gut microbial metabolite, has beneficial effects on glucose homeostasis and has become an attractive drug target for type 2 diabetes (T2D). Recently, we showed that butyrate protects pancreatic beta cells against cytokine-induced dysfunction. In this study, we explored the underlying mechanisms of butyrate action. Pancreatic islets were exposed to a non-cytotoxic concentration of interleukin 1β (IL-1β) for ten days to mimic the low-grade inflammation in T2D. An isoform-selective histone deacetylase 3 (HDAC3) inhibitor normalized IL-1β-reduced GSIS and insulin content similar to the effect of butyrate. In contrast, FFAR2/3 agonists failed to normalize IL-1β-induced impairment of GSIS and reduced insulin content. Butyrate, irrespective of IL-1β, inhibited HDAC activity and increased histone H3 and H4 acetylation by 3- and 10-fold, respectively. Genome-wide analysis of histone H3K27 acetylation (H3K27ac) revealed that butyrate mainly increased H3K27ac at promoter regions (~68 %), while H3K27ac peaks regulated by IL-1β were more equally distributed at promoters (~33 %), introns (~23 %) and intergenic regions (~23 %). Gene ontology analysis showed that butyrate increased IL-1β-reduced H3K27ac levels near several genes related to hormone secretion and reduced IL-1β-increased H3K27ac levels near genes associated with inflammatory responses . Butyrate alone increased H3K27ac near many genes related to MAPK signaling, hormone secretion and differentiation, and decreased H3K27ac at genes involved in cell replication. Together, these results suggest that butyrate prevents IL-1β-induced beta cell dysfunction by inhibition of HDACs resulting in changes in H3K27ac levels at genes relevant for beta cell function and inflammatory responses.
2023-12-07 | GSE233936 | GEO
Project description:Lifestyle intervention including exercise restores glucose homeostasis and pancreatic β-cell function in type 2 diabetes (T2D). However, exercise compliance is a challenge. Novel alternative or adjuvant approaches are necessary. During exercise, the contracting skeletal muscle acts as endocrine organ via the secretion and endocrine signaling of functional proteins. We postulated that contracting skeletal muscle secretes proteins that target pancreatic β-cells and regulate insulin secretion and glucose metabolism. To test this hypothesis, we used an in vitro cell-based skeletal muscle contraction system to uncover proteins released in the muscle secretome. Using an RNAseq screen, we identified growth differentiation factor 15 (GDF15) as a lead candidate. β-cells, human pancreatic islets, and C57BL/6J mice exposed to acute GDF15 treatment exhibited increased glucose-stimulated insulin secretion, and the mechanism involved activation of the insulin release pathway. Chronic GDF15 treatment in db/db mice reduced insulin resistance and preserved pancreatic PDX-1 expression. Consistently, plasma GDF15 increased concurrently with C-peptide prior to the onset of chronic hyperglycemia in humans with pre-diabetes. In addition, in humans with T2D, exercise-induced GDF15 was associated with enhanced β-cell function. These findings support GDF15 as a potential therapeutic target for type 2 diabetes and associated co-morbidities.
2022-10-31 | GSE139872 | GEO