Dataset Information

Impaired ?-cell glucokinase as an underlying mechanism in diet-induced diabetes.

ABSTRACT: High-fat diet (HFD)-fed mouse models have been widely used to study early type 2 diabetes. Decreased ?-cell glucokinase (GCK) expression has been observed in HFD-induced diabetes. However, owing to its crucial roles in glucose metabolism in the liver and in islet ?-cells, the contribution of decreased GCK expression to the development of HFD-induced diabetes is unclear. Here, we employed a ?-cell-targeted gene transfer vector and determined the impact of ?-cell-specific increase in GCK expression on ?-cell function and glucose handling in vitro and in vivo Overexpression of GCK enhanced glycolytic flux, ATP-sensitive potassium channel activation and membrane depolarization, and increased proliferation in Min6 cells. ?-cell-targeted GCK transduction did not change glucose handling in chow-fed C57BL/6 mice. Although adult mice fed a HFD showed reduced islet GCK expression, impaired glucose tolerance and decreased glucose-stimulated insulin secretion (GSIS), ?-cell-targeted GCK transduction improved glucose tolerance and restored GSIS. Islet perifusion experiments verified restored GSIS in isolated HFD islets by GCK transduction. Thus, our data identify impaired ?-cell GCK expression as an underlying mechanism for dysregulated ?-cell function and glycemic control in HFD-induced diabetes. Our data also imply an etiological role of GCK in diet-induced diabetes.This article has an associated First Person interview with the first author of the paper.

SUBMITTER: Lu B

PROVIDER: S-EPMC6031355 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Impaired β-cell glucokinase as an underlying mechanism in diet-induced diabetes.

Lu Brian B Kurmi Kiran K Munoz-Gomez Miguel M Jacobus Ambuludi Egon J EJ Tonne Jason M JM Rakshit Kuntol K Hitosugi Taro T Kudva Yogish C YC Matveyenko Aleksey V AV Ikeda Yasuhiro Y

Disease models & mechanisms 20180613 6

High-fat diet (HFD)-fed mouse models have been widely used to study early type 2 diabetes. Decreased β-cell glucokinase (GCK) expression has been observed in HFD-induced diabetes. However, owing to its crucial roles in glucose metabolism in the liver and in islet β-cells, the contribution of decreased GCK expression to the development of HFD-induced diabetes is unclear. Here, we employed a β-cell-targeted gene transfer vector and determined the impact of β-cell-specific increase in GCK expressio ...[more]

PMID: 29915142

Similar Datasets

Project description:Aims/hypothesisRegulatory factor X 6 (RFX6) is crucial for pancreatic endocrine development and differentiation. The RFX6 variant p.His293LeufsTer7 is significantly enriched in the Finnish population, with almost 1:250 individuals as a carrier. Importantly, the FinnGen study indicates a high predisposition for heterozygous carriers to develop type 2 and gestational diabetes. However, the precise mechanism of this predisposition remains unknown.MethodsTo understand the role of this variant in beta cell development and function, we used CRISPR technology to generate allelic series of pluripotent stem cells. We created two isogenic stem cell models: a human embryonic stem cell model; and a patient-derived stem cell model. Both were differentiated into pancreatic islet lineages (stem-cell-derived islets, SC-islets), followed by implantation in immunocompromised NOD-SCID-Gamma mice.ResultsStem cell models of the homozygous variant RFX6-/- predictably failed to generate insulin-secreting pancreatic beta cells, mirroring the phenotype observed in Mitchell-Riley syndrome. Notably, at the pancreatic endocrine stage, there was an upregulation of precursor markers NEUROG3 and SOX9, accompanied by increased apoptosis. Intriguingly, heterozygous RFX6+/- SC-islets exhibited RFX6 haploinsufficiency (54.2% reduction in protein expression), associated with reduced beta cell maturation markers, altered calcium signalling and impaired insulin secretion (62% and 54% reduction in basal and high glucose conditions, respectively). However, RFX6 haploinsufficiency did not have an impact on beta cell number or insulin content. The reduced insulin secretion persisted after in vivo implantation in mice, aligning with the increased risk of variant carriers to develop diabetes.Conclusions/interpretationOur allelic series isogenic SC-islet models represent a powerful tool to elucidate specific aetiologies of diabetes in humans, enabling the sensitive detection of aberrations in both beta cell development and function. We highlight the critical role of RFX6 in augmenting and maintaining the pancreatic progenitor pool, with an endocrine roadblock and increased cell death upon its loss. We demonstrate that RFX6 haploinsufficiency does not affect beta cell number or insulin content but does impair function, predisposing heterozygous carriers of loss-of-function variants to diabetes.Data availabilityUltra-deep bulk RNA-seq data for pancreatic differentiation stages 3, 5 and 7 of H1 RFX6 genotypes are deposited in the Gene Expression Omnibus database with accession code GSE234289. Original western blot images are deposited at Mendeley ( https://data.mendeley.com/datasets/g75drr3mgw/2 ).

Dataset Information

Impaired ?-cell glucokinase as an underlying mechanism in diet-induced diabetes.

Publications

Impaired β-cell glucokinase as an underlying mechanism in diet-induced diabetes.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets