Project description:The impact of high fat diet on secreted milk small RNA transcriptome was studied by isolating total RNA from milk fat fraction collected on lactation day 10 from control diet fed (C; n=5; 10% fat; 7% sucrose; Research Diets #D12450J, Brunswick, NJ) and high fat diet fed (HF; n=4; Research Diets #D12492, 60% of total kcal energy is fat and match 7% of total kcal is sucrose; Brunswick, NJ) mice.
Project description:The impact of high fat diet on secreted milk small RNA transcriptome was studied by isolating total RNA from milk fat fraction collected on lactation day 10 from control diet fed (C; n=5; 10% fat; 7% sucrose; Research Diets #D12450J, Brunswick, NJ) and high fat diet fed (HF; n=4; Research Diets #D12492, 60% of total kcal energy is fat and match 7% of total kcal is sucrose; Brunswick, NJ) mice.
Project description:Insulin resistance drives the development of type 2 diabetes (T2D). In liver, diacylglycerol (DAG) is a key mediator of lipid-induced insulin resistance. DAG activates protein kinase C epsilon (PKCε), which phosphorylates and inhibits the insulin receptor. In rats, a 3-day high fat diet produces hepatic insulin resistance through this mechanism, and knockdown of hepatic PKCε protects against high fat diet-induced hepatic insulin resistance. Here we employ a systems level approach to uncover additional signaling pathways involved in high fat diet-induced hepatic insulin resistance. We used quantitative phosphoproteomics to map global in vivo changes in hepatic protein phosphorylation in chow-fed, high fat-fed, and high fat-fed with PKCε knockdown rats to distinguish the impact of lipid- and PKCε-induced protein phosphorylation.
Project description:Gene transcription profiling in Epidydimal fat pad (EPD) following High fat versus normal diet in C57/Bl6 mice. Characterisation of molecular mechanisms of in vivo insulin action in mouse models of experimentally induced Insulin resistance. Switched the diet when mice were 5 weeks old, then sampled at 8 days.
Project description:Lipid overload and adipocyte dysfunction are key to the development of insulin resistance and can be induced by a high-fat diet. CD1d-restricted invariant natural killer T (iNKT) cells have been proposed as mediators between lipid overload and insulin resistance, but recent studies found decreased iNKT cell numbers and marginal effects of iNKT cell depletion on insulin resistance under high-fat diet conditions. Here, we focused on the role of iNKT cells under normal conditions. We showed that iNKT cell–deficient mice on a low-fat diet, considered a normal diet for mice, displayed a distinctive insulin resistance phenotype without overt adipose tissue inflammation. Insulin resistance was characterized by adipocyte dysfunction, including adipocyte hypertrophy, increased leptin, and decreased adiponectin levels. The lack of liver abnormalities in CD1d-null mice together with the enrichment of CD1d-restricted iNKT cells in both mouse and human adipose tissue indicated a specific role for adipose tissue–resident iNKT cells in the development of insulin resistance. Strikingly, iNKT cell function was directly modulated by adipocytes, which acted as lipid antigen-presenting cells in a CD1d-mediated fashion. Based on these findings, we propose that, especially under low-fat diet conditions, adipose tissue–resident iNKT cells maintain healthy adipose tissue through direct interplay with adipocytes and prevent insulin resistance. four samples
Project description:We developed a novel network inference approach, Biologically Anchored Knowledge Expansion (BAKE), to analyze large volume gene expression data obtained from a mouse model of insulin resistance progression. Both genetic aspects and dietary factors, specifically high caloric high-fat high-sugar diets, contribute to the progression of insulin resistance. To mimic genetic predisposition, we used a mouse model with double heterozygous deletion of early insulin signaling pathway intermediates, insulin receptor (IR) and insulin receptor substrate 1 (IRS1) genes. These mice were fed with high-fat (Western) or low-fat (Chow) diet for 8 and 16 weeks starting at 8 weeks of age. Gene expression data was collected from adipocytes isolated from these mice. Applying BAKE analysis to the adipocyte gene expression data, we demonstrate that we can accurately discover a novel regulatory gene in the insulin signaling pathway. The mouse model of double heterozygous deletion of insulin receptor (IR) and insulin receptor substrate 1 (IRS1) was originally introduced as a polygenic model to study the development of type 2 diabetes. This mouse model, on an atherosclerosis-prone ApoE null background (IR+/- IRS1+/- ApoE-/-), also shows increased atherosclerotic lesions due to impaired insulin signaling. For our study we used female double heterozygous mice (IR+/- IRS1+/-, 'Dhet' mice or 'Dâ mice) on an ApoE null background (ApoE-/-, âEâ) fed with a Western (high-fat) diet for 8 (DW8, n=5) and 16 (DW16, n=9) weeks starting at 8 weeks of age or with a Chow (low-fat) diet (DC8, n=7; DC16, n=5). There were also ApoE null mice (ApoE-/-, 'Eâ) fed either Western diet for 8 (EW8, n=6) and 16 (EW16, n=8) weeks or Chow diet for 16 weeks (EC16, n=5) starting at 8 weeks of age.
Project description:The aim of this study was to assess whether chronic treatment with RPV can modulate the progression of chronic liver disease, especially of non-alcoholic fatty liver disease (NAFLD), through a nutritional model in wild-type mice Mice were daily treated with RPV (p.o.) and fed with normal or high fat diet during 3 months to induce fatty liver disease
Project description:Lipid overload and adipocyte dysfunction are key to the development of insulin resistance and can be induced by a high-fat diet. CD1d-restricted invariant natural killer T (iNKT) cells have been proposed as mediators between lipid overload and insulin resistance, but recent studies found decreased iNKT cell numbers and marginal effects of iNKT cell depletion on insulin resistance under high-fat diet conditions. Here, we focused on the role of iNKT cells under normal conditions. We showed that iNKT cell–deficient mice on a low-fat diet, considered a normal diet for mice, displayed a distinctive insulin resistance phenotype without overt adipose tissue inflammation. Insulin resistance was characterized by adipocyte dysfunction, including adipocyte hypertrophy, increased leptin, and decreased adiponectin levels. The lack of liver abnormalities in CD1d-null mice together with the enrichment of CD1d-restricted iNKT cells in both mouse and human adipose tissue indicated a specific role for adipose tissue–resident iNKT cells in the development of insulin resistance. Strikingly, iNKT cell function was directly modulated by adipocytes, which acted as lipid antigen-presenting cells in a CD1d-mediated fashion. Based on these findings, we propose that, especially under low-fat diet conditions, adipose tissue–resident iNKT cells maintain healthy adipose tissue through direct interplay with adipocytes and prevent insulin resistance.