Project description:Major causes of lipid accumulation in liver are increased import, synthesis or decreased catabolism of fatty acids. The latter is caused by dysfunction of cellular organelle controlling energy homeostasis, i.e. mitochondria. However, peroxisomes appear to be an important organelle in lipid metabolism of hepatocytes, but little is known about their role in the development of non-alcoholic fatty liver disease (NAFLD). To investigate the role of peroxisomes next to mitochondria in excessive hepatic lipid accumulation we used the leptin resistant db/db mice on C57BLKS background, a mouse model that develops hyperphagia induced diabetes with obesity and NAFLD. We used microarrays to determine differences in hepatic gene expression in a mouse model for NAFDL (BKS.Cg-Leprdb (db/db)) and their wildtype littermates C57BL/KSlepr+/+ (BKS) to determine the effect of persistent hepatic lipid accumulation.
Project description:Hypothesis is that NAMPT overexpression alters liver transcriptomics in genetically diabetic, obese db/db mice. We treated db/db mice n = 4 with adenovirus encoding GFP or NAMPT by tail-vein delivery.
Project description:Nonalcoholic fatty liver disease (NAFLD) is a common disorder in obese people and is becoming the leading cause of hepatocellular carcinoma (HCC). Recently, lncRNAs have been proven to play remarkable roles in numerous biological processes and human diseases, including NAFLD. However, the function of lncRNA in NAFLD pathogenesis remains largely unknown. The aim of this study was to explore the lncRNA expression profile in NAFLD mice and to identify novel lncRNAs involved in the pathogenesis of NAFLD. We performed microarray analysis to compare the expression profiles of lncRNAs and mRNAs in the liver of diabetic db/db mice with NAFLD and normal mice.
Project description:Purpose: To reveal the mechanism of mitochondrial DNA methylation in the progression of fatty liver and insulin resistance. Methods: Liver mitochondrial DNA bisulfite-sequencing of high-fat diet (HFD) and db/db diabetic mice were using Illumina 4000. Western blot, real-time PCR and confocal microscopy were used for further biochemical validation. Results: In the present study, we found increased mitochondrial localization of DNA methyltransferase 1 (DNMT1) in the liver of high-fat diet (HFD) and db/db diabetic mice. Whole genome bisulfite sequencing of mouse liver mtDNA revealed significant increase of cytosine methylation frequencies including CG, CHG and CHH on both L and H-strand in the diabetic mice comparing with normal control, and ND6 showed the most dramatic increase on the L-strand. Conclusions: Our present study suggests an epigenetic regulatory of mitochondrial homeostasis and insulin sensitivity by DNMT1, providing novel therapeutic targets for the prevention and treatment of fatty liver and type 2 diabetes.
Project description:To extract the differentially expressed miRNA between control vs diabetic mice skeletal muscle. We used obese diabetic (C57BL/KsJ db/db) and normal control (C57BL/KsJ db+) mice, which were obtained from the Animal House Facility of the Central Drug Research Institute (CSIR), Lucknow, India.
Project description:Investigation of gene expression level changes in pancreatic and liver tissues of diabetic db/db mice supplemented with selenate, compared to the diabetic db/db mice administered placebo. Fasting blood glucose levels increased continuously in diabetic db/db mice administered placebo (DMCtrl) but decreased gradually in selenate-supplemented diabetic db/db mice (DMSe) and approached normal values when the experiment ended. The size of pancreatic islets increased, causing the plasma insulin concentration to double in DMSe mice compared with that in DMCtrl mice. Two six chip studies using total RNA respectively isolated from pancreatic and liver tissues of three selenate-supplemented diabetic db/db mice, and three diabetic db/db mice administered placebo.
Project description:Purpose: MetS consist of five risk factors: elevated blood pressure and fasting glucose, visceral obesity, dyslipidemia and hypercholesterinemia. The physiological impact of lipid metabolism indicated as visceral obesity and hepatic lipid accumulation is still under debate. One major cause of disturbed lipid metabolism might be dysfunction of cellular organelles controlling energy homeostasis, i.e. mitochondria and peroxisomes. Experimental design: The New Zealand Obese (NZO) mouse model exhibits a polygenic syndrome of obesity, insulin resistance, triglyceridemia and hypercholesterolemia that resembles human metabolic syndrome. We applied a combinatorial approach of lipidomics with liver transcriptomics, 2D-DIGETM and mass spectroscopy based organelle proteomics of highly purified mitochondria and peroxisomes in male mice, to investigate molecular mechanisms related to the impact of lipid metabolism in the pathophysiology of the metabolic syndrome. Conclusions and clinical relevance: Proteome analyses of liver organelles indicated differences in fatty acid metabolism, oxidative stress and response, mainly influenced by PG-C1α/PPARα mediated pathways. These results were in accordance with serum lipid profiles and elevated organelle functionality. These data emphasize that metabolic syndrome is accompanied with increased mitochondria and peroxisomal activity controlling directly cellular energy homeostasis to cope with dyslipidemia and hypercholesterinemia driven hepatic lipid overflow in developing a fatty liver.
Project description:Investigation of gene expression level changes in pancreatic and liver tissues of diabetic db/db mice supplemented with selenate, compared to the diabetic db/db mice administered placebo. Fasting blood glucose levels increased continuously in diabetic db/db mice administered placebo (DMCtrl) but decreased gradually in selenate-supplemented diabetic db/db mice (DMSe) and approached normal values when the experiment ended. The size of pancreatic islets increased, causing the plasma insulin concentration to double in DMSe mice compared with that in DMCtrl mice.
Project description:Type 2 diabetes mellitus (TM) is a severely metabolic disorder that affects above 10% worldwide population. Obesity is a major cause of insulin resistance and contributes to the development of TM. Liver is an essential metabolic organ that plays crucial roles in the pathogenesis of obesity and diabetes. However, the underlying mechanisms of liver in the transition of obesity to diabetes are not fully understood. Nonhuman primate (NHP) rhesus monkey is an appropriate animal for research of human diseases. Here, we first screened and selected three individual spontaneous and diabetic rhesus monkeys. Interestingly, the diabetic monkeys were obese with high BMI at beginning, but gradually lost their body weight during one-year observation. Furthermore, we performed a SILAC-based quantitative proteomics to identify proteins and signaling pathways with altered expression in the liver of obese and diabetic monkeys. Totally, 3509 proteins were identified and quantified, and of which 185 proteins displayed altered expression level. GO analysis revealed that the expression of proteins involved in fatty acids β-oxidation and galactose metabolism was increased in obese monkeys; while proteins involved in oxidative phosphorylation (OXPHOS) and branched chain amino acid (BCAA) degradation was upregulated in diabetic monkeys. In addition, we observed a mild impaired mitophagy and apoptosis in the liver of diabetic monkeys, suggesting a dysfunction of mitochondria and liver injury in the late onset of diabetics. Taken together, our liver proteomics may reveal a distinct metabolic transition from fatty acids β-oxidation in obese monkey to BCAA degradation in diabetic monkeys.
Project description:Small RNA profiles in the liver of 9-week old wild type and diabetic db/db mice were measured to detect the differentially expressed small RNAs. Small RNA profiles of 9-week old wild type (WT) and diabetic db/db mice were generated by deep sequencing using Illumina Genome Analyzer.