RNA seq of pancreatic islets isolated from free fatty acid receptor 3 knockout (Ffar3 KO) and wildtype (Ffar3 WT) male mice
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE67991 | GEO | 2016/01/01
SECONDARY ACCESSION(S): PRJNA281457
REPOSITORIES: GEO
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Project description:The short chain fatty acid (SCFA) receptor (free fatty acid receptor-3; FFAR3) is expressed in pancreatic beta cells; however, its role in insulin secretion is not clearly defined. Here, we examined the role of FFAR3 in insulin secretion. Using islets from global knockout FFAR3 (Ffar3-/-) mice, we explored the role of FFAR3 and ligand-induced FFAR3 signaling on glucose stimulated insulin secretion. RNA sequencing was also performed to gain greater insight into the impact of FFAR3 deletion on the islet transcriptome. First exploring insulin secretion, it was determined that Ffar3-/- islets secrete more insulin in a glucose-dependent manner as compared to wildtype (WT) islets. Next, exploring its primary endogenous ligand, propionate, and a specific agonist for FFAR3, signaling by FFAR3 inhibited glucose-dependent insulin secretion, which occurred through a Gαi/o pathway. To help understand these results, transcriptome analyses by RNA-sequencing of Ffar3-/- and WT islets observed multiple genes with well known roles in islet biology to be altered by genetic knockout of FFAR3. Our data shows that FFAR3 signaling mediates glucose stimulated insulin secretion through Gαi/o sensitive pathway. Future studies are needed to more rigorously define the role of FFAR3 by in vivo approaches. Analysis of total RNA from 3 biological replicates of pancreatic islets isolated from free fatty acid receptor 3 knockout (Ffar3 KO) and wildtype (Ffar3 WT) male mice
2016-07-03 | E-GEOD-67991 | biostudies-arrayexpress
Project description:Increased fat intake is associated with obesity and insulin resistance. In some individuals, a failure of pancreatic b-cells to increase insulin production in response to the high demands of obesity leads to diabetes. We sought to determine whether the impaired b- cell adaptation in obesity is associated with differential expression of genes involved in b-cell expansion and intermediary metabolism. Two strains of inbred mice prone to obesity, C57Bl/6J and AKR/J, were fed regular rodent chow or high-fat diet, after which islet morphology, secretory function and gene expression were assessed. AKR/J had lower blood glucose and higher insulin levels compared with C57Bl/6J mice on regular rodent chow or high fat diet. Insulin secretion was 3.2 fold higher in AKR/J than C57Bl/6J mice following intraperitoneal glucose injection. Likewise, glucose-stimulated insulin secretion from isolated islets was higher in AKR/J. Additionally, islet mass was 1.4 fold greater in AKR/J compared with C57Bl/6J. To elucidate the factors associated with the differences in insulin, we analyzed the gene expression profiles in pancreatic islets in AKR/J and C57Bl/6J mice. Of 14,000 genes examined, 220 were up-regulated and 286 were down-regulated in islets from diet-induced obese AKR/J mice compared with C57Bl/6J mice. Key genes involved in islet signaling and metabolism, e.g. glucagon like peptide-1 receptor, sterol Co-A desaturase 1 & 2 and fatty acid desaturase 2 were upregulated in obese AKR/J mice. The expression of multiple extracellular matrix proteins was also increased in AKR/J mice, suggesting a role in modulation of islet mass. Functional analyses of differentially regulated genes hold promise for elucidating factors linking obesity to alterations in islet function. Experiment Overall Design: Microarray analyses were performed on quadruplicate RNA samples of pancreatic islets from AKR and Bl6 mice placed on high-fat diet for 3 months. Pancreases from two mice were combined to yield one sample of islet RNA. All protocols were conducted as described in the Affymetrix GeneChips Expression Analysis Technical Manual (Affymetrix, Santa Clara, CA) using 5 μg total RNA and GeneChip Mouse Expression Arrays MOE 430 (Affymetrix).
2008-04-07 | E-GEOD-10639 | biostudies-arrayexpress
Project description:The NF-κB pathway is a master regulator of inflammatory processes and is implicated in insulin resistance and pancreatic beta cell dysfunction in the metabolic syndrome. While canonical NF-κB signaling is well studied, there is little information on the divergent non-canonical NF-κB pathway in the context of pancreatic islet dysfunction in diabetes. Here, we demonstrate that pharmacological activation of the non-canonical NF-κB inducing kinase (NIK) disrupts glucose homeostasis in zebrafish in vivo. Further, we identify NIK as a critical negative regulator of beta cell function as pharmacological NIK activation results in impaired glucose-stimulated insulin secretion in mouse and human islets. NIK levels are elevated in pancreatic islets isolated from diet-induced obese (DIO) mice, which exhibit increased processing of non-canonical NF-κB components p100 to p52, and accumulation of RelB. Tumor necrosis factor α (TNFα) and receptor activator of NF-κB ligand (RANKL), two ligands associated with diabetes, induce NIK in islets. Mice with constitutive beta cell intrinsic NIK activation present impaired insulin secretion with DIO. NIK activation triggers the non-canonical NF-κB transcriptional network to induce genes identified in human type 2 diabetes genome-wide association studies linked to beta cell failure. These studies reveal that NIK contributes a central mechanism for beta cell failure in diet-induced obesity. We identify a role for Nuclear Factor inducing κB (NIK) in pancreatic beta cell failure. NIK activation disrupts glucose homeostasis in zebrafish in vivo and impairs glucose-stimulated insulin secretion in mouse and human islets in vitro. NIK activation also perturbs beta cell insulin secretion in a diet-induced obesity mouse model. These studies reveal that NIK contributes a central mechanism for beta cell failure in obesity. To uncover the role of NIK in pancreatic beta cells, we performed a gene expression microarray analysis comparing pancreatic islets with constitutive beta cell intrinsicNIK activation from the 16 week old mice (beta cell specific TRAF2 and TRAF2 knockout mice) to their controls (n=3 per group).
2015-06-18 | E-GEOD-68317 | biostudies-arrayexpress
Project description:The IL-22RA1 receptor is highly expressed in the pancreas, and exogenous IL-22 has been shown to reduce endoplasmic reticulum and oxidative stress in human pancreatic islets and promote secretion of high-quality insulin from beta-cells. However, the endogenous role of IL-22RA1 signaling on these cells remains unclear. Here, we show that antibody neutralisation of IL-22RA1 in cultured human islets leads to impaired insulin quality and increased cellular stress. Through the generation of mice lacking IL-22ra1 specifically on pancreatic alpha- or beta-cells, we demonstrate that ablation of murine beta-cell IL-22ra1 leads to similar decreases in insulin secretion, quality and islet regeneration, whilst increasing islet cellular stress, inflammation and MHC II expression. These changes in insulin secretion led to impaired glucose tolerance, a finding more pronounced in female animals compared to males. Our findings attribute a regulatory role for endogenous pancreatic beta-cell IL-22ra1 in insulin secretion, islet regeneration, inflammation/cellular stress and appropriate systemic metabolic regulation.
2024-04-16 | GSE262867 | GEO
Project description:UDP-sugars were identified as extracellular signaling molecules, assigning a new function to these compounds in addition to their well defined role in intracellular substrate metabolism and storage. Previously regarded as an orphan receptor, the G protein-coupled receptor (GPCR) P2Y14 (GPR105) was found to bind extracellular UDP and UDP-sugars. Little is known about the physiological functions of this GPCR. To study its physiological role we used a gene-deficient (KO) mouse strain expressing the bacterial LacZ reporter gene to monitor the physiological expression pattern of P2Y14. We found that P2Y14 is mainly expressed in pancreas and salivary glands and in subpopulations of smooth muscle cells of the gastrointestinal tract, blood vessels, lung and uterus. Among other phenotypical differences KO mice showed a significantly impaired glucose tolerance following oral and intraperitoneal glucose application. An unchanged insulin tolerance suggested altered pancreatic islet function. Transcriptome analysis of pancreatic islets showed that P2Y14 deficiency significantly changed expression of components involved in insulin secretion. Insulin secretion tests revealed a reduced insulin release from P2Y14-deficient islets highlighting P2Y14 as a new modulator of proper insulin secretion. 10 samples from pancreatic islets isolated from wildtype mice; 10 samples from pancreatic islets isolated from P2Y14-knockout mice
2014-07-11 | E-GEOD-59285 | biostudies-arrayexpress
Project description:Hyperinsulinemia often precedes type 2 diabetes but its role in disease progression is unknown. Palmitoylation, a protein modification implicated in regulated exocytosis, is reversed by acyl-protein thioesterase 1 (APT1). We found altered APT1 biology in pancreatic islets from humans with type 2 diabetes, and APT1 knockdown in nondiabetic human islets caused insulin hypersecretion. Chow fed global and islet specific APT1 knockout mice had enhanced glucose tolerance due to islet autonomous increased glucose-stimulated insulin secretion. APT1 deficiency did not affect islet calcium dynamics but prolonged insulin granule fusion. Using palmitoylation proteomics, we identified Scamp1 as an APT1 substrate that localized to insulin secretory granules. Knockdown of Scamp1 caused insulin hypersecretion. APT1 deficient insulinoma cells subjected to nutrient excess had increased apoptosis, and expression of a mutated Scamp1 incapable of being palmitoylated in APT1 deficient cells rescued insulin hypersecretion and nutrient induced apoptosis. Compared to APT1 sufficient controls, high fat fed islet specific APT1 knockout mice and global APT1 deficient db/db mice showed increased -cell failure. These findings suggest that the depalmitoylation enzyme APT1 is regulated in human islets, and that APT1 deficiency causes insulin hypersecretion leading to -cell failure, modeling the evolution of some forms of human type 2 diabetes.
2023-11-05 | PXD038554 | Pride
Project description:Increased fat intake is associated with obesity and insulin resistance. In some individuals, a failure of pancreatic b-cells to increase insulin production in response to the high demands of obesity leads to diabetes. We sought to determine whether the impaired b- cell adaptation in obesity is associated with differential expression of genes involved in b-cell expansion and intermediary metabolism. Two strains of inbred mice prone to obesity, C57Bl/6J and AKR/J, were fed regular rodent chow or high-fat diet, after which islet morphology, secretory function and gene expression were assessed. AKR/J had lower blood glucose and higher insulin levels compared with C57Bl/6J mice on regular rodent chow or high fat diet. Insulin secretion was 3.2 fold higher in AKR/J than C57Bl/6J mice following intraperitoneal glucose injection. Likewise, glucose-stimulated insulin secretion from isolated islets was higher in AKR/J. Additionally, islet mass was 1.4 fold greater in AKR/J compared with C57Bl/6J. To elucidate the factors associated with the differences in insulin, we analyzed the gene expression profiles in pancreatic islets in AKR/J and C57Bl/6J mice. Of 14,000 genes examined, 220 were up-regulated and 286 were down-regulated in islets from diet-induced obese AKR/J mice compared with C57Bl/6J mice. Key genes involved in islet signaling and metabolism, e.g. glucagon like peptide-1 receptor, sterol Co-A desaturase 1 & 2 and fatty acid desaturase 2 were upregulated in obese AKR/J mice. The expression of multiple extracellular matrix proteins was also increased in AKR/J mice, suggesting a role in modulation of islet mass. Functional analyses of differentially regulated genes hold promise for elucidating factors linking obesity to alterations in islet function. Keywords: response to high fat diet
2008-02-28 | GSE10639 | GEO
Project description:Tafazzin is a transacylase which causes the content and molecular structure of cardiolipin (CL) to be altered in the inner mitochondrial membrane. The enzymatic machinery responsible for oxidative respiration are localized to the inner mitochondrial membrane and require CL for activity. As a result, tafazzin is critical for maintaining mitochondrial function. In beta-cells, which are the insulin secreting cells in pancreatic islets, mitochondrial function is linked to insulin secretion. We previously established that tafazzin knock-down mice were lean and maintained insulin sensitivity compared to the obese insulin resistant control litter mates. However, it was unknown whether tafazzin deficiency also influenced insulin secretion in the establishment of the lean phenotype. Using X week-old mice, we ascertained that the number of beta-cells was similar between genotypes. Ex vivo insulin secretion under low glucose conditions was reduced (52%) from islets isolated from tafazzin knock-down mice. Consistent with this tafazzin knock-down mice exhibited reduced fasting insulin plasma insulin levels. Measurement of mitochondrial oxygen consumption revealed that basal oxygen consumption was reduced (58%) in islets from tafazzin-deficient animals. The addition of etomoxir, an inhibitor of mitochondrial fatty acid translocation, significantly elevated basal mitochondrial respiration (5-fold) in islets from tafazzin knockdown mice, indicating a significant fatty acid-mediated inhibitory effect. In contrast, etomoxir lacked any measurable effect on control wild-type islets. The altered mitochondrial function identified in taffazin knock-down islets was not associated with reduced CL content or elevated oxyCL species. Our experiments indicate that tafazzin plays a key role in regulating normal islet beta-cell function.
2021-07-31 | GSE136242 | GEO
Project description:Pancreatic islets control glucose homeostasis by the balanced secretion of insulin and other hormones, and its abnormal function causes diabetes or hypoglycemia. Here, we uncover a conserved program of alternative microexons included in mRNAs of islet cells, particularly in genes involved in vesicle transport and exocytosis. Islet microexons (IsletMICs) are regulated by the RNA binding protein SRRM3 and represent a subset of the larger neural program that are particularly sensitive to the levels of this protein. Both SRRM3 and IsletMICs are induced by elevated glucose levels, and depletion of SRRM3 in beta cell lines and mouse islets, or repression of particular IsletMICs using antisense oligonucleotides, leads to inappropriate insulin secretion. Consistently, SRRM3 mutant mice display defects in islet cell identity and function, leading to hyperinsulinemic hypoglycemia. Importantly, human genetic variants that influence SRRM3 expression and microexon inclusion in islets are associated with fasting glucose variation and type 2 diabetes risk.
2022-12-14 | GSE198906 | GEO
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