The Stearyl CoA desaturase is a gatekeeper that protects human ß cells against lipotoxicity and maintains their identity
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE130208 | GEO | 2019/12/02
REPOSITORIES: GEO
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Project description:The Stearyl CoA desaturase is a gatekeeper that protects human ß cells against lipotoxicity and maintains their identity
| PRJNA534282 | ENA
Project description:Aims/hypothesisDuring the onset of type 2 diabetes, excessive dietary intake of saturated NEFA and fructose lead to impaired insulin production and secretion by insulin-producing pancreatic beta cells. The majority of data on the deleterious effects of lipids on functional beta cell mass were obtained either in vivo in rodent models or in vitro using rodent islets and beta cell lines. Translating data from rodent to human beta cells remains challenging. Here, we used the human beta cell line EndoC-βH1 and analysed its sensitivity to a lipotoxic and glucolipotoxic (high palmitate with or without high glucose) insult, as a way to model human beta cells in a type 2 diabetes environment.MethodsEndoC-βH1 cells were exposed to palmitate after knockdown of genes related to saturated NEFA metabolism. We analysed whether and how palmitate induces apoptosis, stress and inflammation and modulates beta cell identity.ResultsEndoC-βH1 cells were insensitive to the deleterious effects of saturated NEFA (palmitate and stearate) unless stearoyl CoA desaturase (SCD) was silenced. SCD was abundantly expressed in EndoC-βH1 cells, as well as in human islets and human induced pluripotent stem cell-derived beta cells. SCD silencing induced markers of inflammation and endoplasmic reticulum stress and also IAPP mRNA. Treatment with the SCD products oleate or palmitoleate reversed inflammation and endoplasmic reticulum stress. Upon SCD knockdown, palmitate induced expression of dedifferentiation markers such as SOX9, MYC and HES1. Interestingly, SCD knockdown by itself disrupted beta cell identity with a decrease in mature beta cell markers INS, MAFA and SLC30A8 and decreased insulin content and glucose-stimulated insulin secretion.Conclusions/interpretationThe present study delineates an important role for SCD in the protection against lipotoxicity and in the maintenance of human beta cell identity.Data availabilityMicroarray data and all experimental details that support the findings of this study have been deposited in in the GEO database with the GSE130208 accession code.
| S-EPMC6946759 | biostudies-literature
Project description:Background: Prolonged exposure to elevated free fatty acids induces β-cell failure (lipotoxicity) and contributes to the pathogenesis of type 2 diabetes. In vitro exposure of β-cells to the saturated free fatty acid palmitate is a valuable model of lipotoxicity, reproducing features of β-cell failure observed in type 2 diabetes. In order to map the β-cell response to lipotoxicity, we combined RNA-sequencing of palmitate-treated human islets with iTRAQ proteomics of insulin-secreting INS-1E cells following a time course exposure to palmitate. Results: Crossing transcriptome and proteome of palmitate-treated β-cells revealed 85 upregulated and 122 downregulated genes at both transcript and protein level. Pathway analysis identified lipid metabolism, oxidative stress, amino-acid metabolism and cell cycle pathways among the most enriched palmitate-modified pathways. Palmitate induced gene expression changes compatible with increased free fatty acid mitochondrial import and β-oxidation, decreased lipogenesis and modified cholesterol transport. Palmitate modified genes regulating endoplasmic reticulum (ER) function, ER-to-Golgi transport and ER stress pathways. Furthermore, palmitate modulated cAMP/protein kinase A (PKA) signaling, inhibiting expression of PKA anchoring proteins and downregulating the GLP-1 receptor. SLC7 family amino-acid transporters were upregulated in response to palmitate but this induction did not contribute to β-cell demise. To unravel critical mediators of lipotoxicity upstream of the palmitate-modified genes, we identified overrepresented transcription factor binding sites and performed network inference analysis. These identified LXR, PPARα, FOXO1 and BACH1 as key transcription factors orchestrating the metabolic and oxidative stress responses to palmitate. Conclusions: This is the first study to combine transcriptomic and sensitive time course proteomic profiling of palmitate-exposed β-cells. Our results provide comprehensive insight into gene and protein expression changes, corroborating and expanding beyond previous findings. The identification of critical drivers and pathways of the β-cell lipotoxic response points to novel therapeutic targets for type 2 diabetes.
2020-08-13 | GSE156109 | GEO
Project description:We define a pathogenic role for a ß-catenin-activated genetic pathway in murine renal dysplasia. Cre-mediated stabilization of ß-catenin in the ureteric cell lineage prior to the onset of kidney development increased ß-catenin levels and caused renal aplasia or severe hypodysplasia. A genome-wide analysis of mRNA expression in dysplastic tissue identified down-regulation of genes required for ureteric branching and up regulation of Tgfß2 and Dkk1. Hoxb7-Cre:EGFP mice ( Zhao, et al. (2004) Dev Biol 276:403-415) were crossed with mice containing loxP sites flanking exon 3 of the ß-catenin allele (ß-catdelta3/delta3) (Harada,et al. (2002) Cancer Res 62:1971-1977) to generate ß-catenin gain-of-function mutant mice specific to the uteric bud, termed ß-catGOF-UB .Eighteen ß-catGOF-UB mutant kidneys and 9 WT kidneys were micro-dissected at E12.5. Mutant kidneys were divided into three random pools (n=3) consisting of 6 kidneys each and mRNA expression assessed by microarray.
2011-03-28 | E-GEOD-20325 | biostudies-arrayexpress
Project description:The ability to isolate pure pancreatic ß-cells would greatly aid multiple areas of diabetes research. We developed an exendin-4-like neopeptide conjugate for the rapid purification and isolation of functional pancreatic ß-cells. By targeting the glucagon-like peptide-1 receptor, ß-cells were isolated within an hour and were >99% pure. These studies were confirmed by immunostaining, confocal microscopy and microarray analysis on isolated cells. Gene expression profiling studies of the cytofluorometrically sorted ß-cells provided new insights into the genetic programs at play of different ages and stages during type-1 diabetes development. The described isolation method should have broad applicability to the ß-cell field. Microarray profile of beta cells from isolated islets from 4 and 12 week old NOD mice. Cells were stained with 50 nM Ex4+ probe and sorted on FACS ARIA. DAPI and CD45+ cells were excluded.
2015-09-04 | E-GEOD-64508 | biostudies-arrayexpress
Project description:In bone diseases such as osteonecrosis and osteoporosis, a shift toward a preferential differentiation of mesenchymal stromal cells (MSC) into adipocytes at the expense of the osteoblastic lineage is described, leading to excessive accumulation of adipocytes in the bone marrow of the patients. The influence of cytokines and adipokines secreted by adipocytes on skeletal health is already well-documented but the impact of free fatty acids release on bone cell biology and viability is an emerging concept. We have previously demonstrated that the saturated fatty acid (SFA) palmitate (Palm) is cytotoxic for human MSC (hMSC) and osteoblasts whereas oleate (Ole), a monounsaturated fatty acid (MUFA), has no toxic effect. Moreover, Ole protects cells against lipotoxicity. Our observations led us to propose that the toxicity of the SFA is not correlated to its intracellular accumulation but could rather be related to the intracellular SFA/MUFA ratio, which finally determines the toxic effect of SFA. Therefore, in the present study, we have investigated the potential protective role of the enzyme stearoyl-CoA 9-desaturase 1 (SCD1) against the deleterious effects of Palm. SCD1 is an enzyme responsible for desaturation of SFA to MUFA; its activation could therefore lead to modifications of the intracellular SFA/MUFA ratio. In the present study, we showed that hMSC express SCD1 and liver X receptors (LXRs), transcription factors regulating SCD1 expression. Human MSC treatment with a LXRs agonist triggered SCD1 expression and drastically reduced Palm-induced cell mortality, caspases 3/7 activation, endoplasmic reticulum stress and inflammation. We also observed that, in the presence of Palm, the LXRs agonist provoked lipid droplets formation, augmented the total cellular neutral lipid content but decreased the SFA/MUFA ratio when compared to Palm treatment alone. Addition of an inhibitor of SCD1 activity abrogated the positive effects of the LXRs agonist, suggesting that SCD1 could play a key role in protecting hMSC against lipotoxicity.
| S-EPMC6822410 | biostudies-literature
Project description:Interventions: Experimental group:ß- hydroxy- ß- methyl butyrate;Control Group:No
Primary outcome(s): skeletal muscle index;tumor necrosis factor-like weak apoptosis-inducing factor;peroxisome proliferator-activated receptor coactivator 1-a;growth differentiation factor 15;grip strength;pace;leg circumference
Study Design: Parallel
| 2716507 | ecrin-mdr-crc
Project description:The ability to isolate pure pancreatic ß-cells would greatly aid multiple areas of diabetes research. We developed an exendin-4-like neopeptide conjugate for the rapid purification and isolation of functional pancreatic ß-cells. By targeting the glucagon-like peptide-1 receptor, ß-cells were isolated within an hour and were >99% pure. These studies were confirmed by immunostaining, confocal microscopy and microarray analysis on isolated cells. Gene expression profiling studies of the cytofluorometrically sorted ß-cells provided new insights into the genetic programs at play of different ages and stages during type-1 diabetes development. The described isolation method should have broad applicability to the ß-cell field.
2015-09-04 | GSE64508 | GEO
Project description:ß-catenin is a main oncogene in a large number of cancers (colorectal, liver, melanoma, uterus). Local immunosuppression induced by certain cancers remains a major problem of resistance to immunotherapies and its molecular mechanism remains poorly understood. Recently, ß-catenin mutated tumors (hepatocellular carcinoma (HCC) and melanoma) have been described as promoting immune evasion and resistance to anti-PD1 immunotherapy. Based on preliminary data obtained in HCC, we hypothesize that a defect in intercellular communication could be the cause of this immune evasion. The main objective of this project is to identify proteomic signatures of factors that can induce this immune escape in ß-catenin mutated HCC such as exosomes.
2024-07-08 | PXD043841 | Pride
Project description:We define a pathogenic role for a ß-catenin-activated genetic pathway in murine renal dysplasia. Cre-mediated stabilization of ß-catenin in the ureteric cell lineage prior to the onset of kidney development increased ß-catenin levels and caused renal aplasia or severe hypodysplasia. A genome-wide analysis of mRNA expression in dysplastic tissue identified down-regulation of genes required for ureteric branching and up regulation of Tgfß2 and Dkk1.
2011-03-28 | GSE20325 | GEO