Insulin Receptor-Overexpressing beta-Cells Ameliorate Hyperglycemia in Diabetic Rats through Wnt Signaling Activation
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ABSTRACT: To investigate the therapeutic efficacy of beta-cells with IR manipulation, a plasmid containing human IR was stably introduced into rat beta-cell line INS-1 cells (namely, INS-IR cells). In the INS-IR cells, the role of cross-talk between insulin and Wnt signaling pathways in improving the functionality of beta-cells was investigated.
Project description:Mass spectrometry identification of Trypanosoma brucei bloodstream form proteins that interacts with Ins(1,4,5)P3 and Ins(1,3,4,5)P4.
Project description:Differentiation of INSGFP/w hESCs using published protocols demonstrated that all GFP+ cells co-expressed insulin, confirming the fidelity of the reporter gene. INS-GFP+ cells also co-expressed glucagon and somatostatin, confirming prior studies regarding the polyhormonal nature of early hESC derived insulin-expressing cells. INSGFP/w hESCs were employed to develop a 96 well format spin Embryoid Body (EB) differentiation protocol that utilized the recombinant protein based fully defined medium, APEL. Like INS-GFP+ cells generated with other methods, those derived using the spin EB protocol expressed a collection of pancreatic related transcription factors including ISL1, PAX6 and NKX2.2. However, in contrast to previous methods, the spin EB protocol yielded INS-GFP+ cells that also co-expressed the beta-cell transcription factor, NKX6.1 and comprised a substantial proportion of monohormonal insulin+ cells.
Project description:The aim of this experiment was to observe the transcriptional profile of Ins+ cells in human cadaveric islets and at the terminal stage of our in vitro beta-cell differentiation protocol across both the Hues8 and H1 cell lines. One polyhormonal sample (Ins+/Gcg+) was also sorted for additional comparison.
Project description:The aim of the present study was to explore the transcriptome of pancreatic islets and, based on this information, to prepare a comprehensive and open access inventory of insulin-producing ?-cell gene expression, the beta-Cell Gene Atlas (BCGA). INS-1 cells, primary rat beta-cells (>87% beta-cells) and non-beta-cells (<3% beta cells, mostly alpha) were isolated by FACS mediated purification of two different rat islet preparations.
Project description:Cytokine-induced beta-cell apoptosis is a key event for the death of pancreatic beta cells in the development of type-1 diabetes. We identified BRD0476 as a novel suppressor of cytokine-induced beta-cell apoptosis. We used microarrays to look for gene set(s) that are regulated by BRD0476. Rat INS-1E cells were treated with cytokine cocktails (IL-1b, IFN-g and TNF-a) and/or BRD0476 for 6 or 12 hours. Total RNAs were isolated using the RNEasy kit from Qiagen.
Project description:We have performed gene expression microarray analysis to profile transcriptomic signatures between insulin resistance high risk subjects and insulin resistance low risk subjects Participants enrolled in this study were recruited in the overnight fasted state, then the collection and processing of glucose (fasting, 30, 60 and 120 minutes) and insulin from blood samples, hemoglobin A1c (HbA1c) , assessment of medical history, socio-demographic characteristics, lifestyle factors, blood pressure and anthropometric and body composition measurements were conducted. During baseline visit, participants were asked to refrain from eating, drinking and oral hygiene procedures for at least 1-hour prior to saliva collection.5 ml of unstimulated whole saliva samples were consistently collected, stabilized and preserved, the sample supernatants were reserved at -80°C prior to assay. Based on the homeostasis model assessment of insulin resistance (HOMA-IR), using the formula [HOMA-IR= (fasting glucose*fasting insulin)/405], participants were divided into 2 groups: IR high risk group (HOMA-IR value ?2.5) and IR low risk group (HOMA-IR value <2.5). Total RNA was extracted from saliva and subjected to gene expression microarray analysis using Affymetrix human genome 2.0 plus array
Project description:Pancreatic β-cells have the key homeostatic function of releasing insulin to keep blood glucose in the normal range. It is not fully understood how β-cell mass is determined. Ablation of a nuclear receptor, chicken ovalbumin upstream promoter transcription factor II (COUP-TFII), in mouse pancreatic β-cells results in glucose intolerance and 50% fewer β-cells during the postnatal period. By testing islets isolated from these mice and cultured β-cells with loss and gain of COUP-TFII function, we found that COUP-TFII induces β-catenin thus upregulating target genes like cyclin D1. Beta-cell expansion triggered by glucagon-like peptide 1 (GLP-1) is known to be mediated by β-catenin controlling cyclin D1. We show that in the absence of COUP-TFII, exendin-4, an agonist of the GLP-1 receptor, does not fully induce cyclin D1 expression, while overexpression of β-catenin induces cyclin D1. A marked decrease in cyclin D1 expression is detected in islets isolated from transgenic mice lacking both GLP-1 receptor and gastric inhibitory peptide receptor. COUP-TFII is therefore required for GLP-1 activation of the β-catenin-dependent pathway in pancreatic β-cells to increase β-cell number. To understand the molecular mechanisms by which COUP-TFII controls β-cell mass, we determined the RNA profile of COUP-TFII knockdown β-cells using Affymetrix oligonucleotide microarrays. Computational analysis identified clusters of genes shared by different gene regulatory Networks that are up or down regulated namely genes involved in Wnt/β-catenin signaling, insulin signaling and lipid/carbohydrate metabolism. We determined the RNA profile of COUP-TFII knockdown β-cells (832/13 INS-1 cells transfected with COUP-TFII specific siRNA) with respect to control cells (832/13 INS-1 cells transfected with scrambled siRNA) using Affymetrix expression analysis technical manual 701025Rev.5 (Affymetrix, Santa Clara, California, USA). Briefly, 1 mg of total cellular mRNA was reverse transcribed into cDNA (SuperScript Choice System Invitrogen, Carlsbad, CA) using oligo-dT primers and a T7 RNA polymerase promoter site. The cDNA was in vitro transcribed and biotin-labeled for microarray analysis using the Affymetrix IVT labeling kit. The concentration of labelled cRNA was measured using a NanoDrop ND-1000 spectrophotometer. Labeled cRNA was fragmented in a fragmentation buffer for 35 min at 94°C. The quality of labeled and fragmented cRNA was analyzed using the Agilent bioanalyzer 2100 (Van Lommel et al, 2006). Fragmented cRNA was hybridized to the rat 230 2.0 array (Affymetrix) during 16h at 45°C. Arrays were washed and stained in a fluidics station (Affymetrix) and scanned using the Affymetrix 3000 GeneScanner.
Project description:We have demonstrated that the communication between macrophages and lung cancer cells via macrophage-derived insulin-like growth factor 2 (IGF2) drives lung cancer progression. As a mechanism of action, we found that insulin receptor (IR) was rapidly activated and translocated to the cytosol and nucleus in response to IGF2 stimulation, and nuclearly translocated IR was associated with chromatin. Therefore, we carried out LC-MS/MS analysis to identify the nuclear proteins associated with IR.
Project description:Diabetes is a global health problem caused primarily by the inability of pancreatic β-cells to secrete adequate levels of insulin. The molecular mechanisms underlying the progressive failure of β-cells to respond to glucose in type-2 diabetes remain unresolved. Using a combination of transcriptomics and proteomics, we find significant dysregulation of major metabolic pathways in islets of diabetic βV59M mice, a non-obese, eulipidaemic diabetes model. Multiple genes/proteins involved in glycolysis/gluconeogenesis are upregulated, whereas those involved in oxidative phosphorylation are downregulated. In isolated islets, glucose-induced increases in NADH and ATP are impaired and both oxidative and glycolytic glucose metabolism are reduced. INS-1 β-cells cultured chronically at high glucose show similar changes in protein expression and reduced glucose-stimulated oxygen consumption: targeted metabolomics reveals impaired metabolism. These data indicate hyperglycaemia induces metabolic changes in β-cells that markedly reduce mitochondrial metabolism and ATP synthesis. We propose this underlies the progressive failure of β-cells in diabetes.
Project description:Locally released cytokines contribute to beta cell dysfunction and apoptosis in Type 1 diabetes. In vitro exposure of insulin producing INS-1E cells to the cytokines interleukin (IL)-1beta + interferon (IFN) gamma leads to a significant increase in apoptosis. To characterize the genetic networks implicated in beta cell dysfunction and apoptosis and its dependence on nitric oxide (NO) production, we performed a time course analysis using the Affymetrix RG U34A microarry. INS-1E cells were exposed in duplicate to IL-1beta + IFN-gamma for six different time points (1, 2, 4, 8, 12, and 24 h) with or without the inducible NO synthase blocker.