Project description:Xbp1 is an important regulator of unfolded protein response and lipid metabolism. Its dyregulation has been associcated in human NASH. Feeding a high fat diet with fructose/sucrose to mice causes progressive, fibrosing steatohepatitis. This study is to use RNA-Seq to identify differentially expressed genes in hepatic Xbp1 deficient mice livers fed with a high fat diet compared to controls. Hepatic Xbp1 deficient mice or flox controls were fed either regular chow or a high fat diet (n=4). Samples from each cohort were pooled into two replicates.
Project description:Non-alcoholic fatty liver disease (NAFLD) is a highly prevalent form of hepatic disease and feeding mice a High-Fat, High-Caloric (HFHC) diet is a standard model of NAFLD. In order to better understand the genetic basis of NAFLD, we conducted an expression quantitative trait locus (eQTL) analysis of mice fed a HFHC diet. 265 (A/J × C57BL/6J) F2 male mice were fed a HFHC diet for 8 weeks. QTL analysis was utilized to identify genomic regions that regulate hepatic gene expression of Xbp1s and Socs3. We identified two overlapping loci for Xbp1 and Socs3 on Chr 1 (164.0-185.4 Mb and 174.4-190.5 Mb, respectively) and Chr 11 (41.1-73.1 Mb and 44.0-68.6 Mb, respectively), and an additional locus for Socs3 on Chr 12 (109.9-117.4 Mb). C57BL/6J-Chr 11A/J/ NaJ mice fed a HFHC diet manifested the A/J phenotype of increased Xbp1s and Socs3 gene expression (p<0.05), while C57BL/6J-Chr 1A/J/ NaJ mice retained the C57BL/6 phenotype. In addition, we replicated the eQTLs on Chr 1 and 12 (LOD scores ? 3.5) using mice from the BXD murine reference panel challenged with CCl4 to induce chronic liver injury and fibrosis. We have identified overlapping eQTLs for Xbp1 and Socs3 on Chr 1 and 11, and consomic mice confirmed that replacing the C57BL/6 with the A/J Chr 11 resulted in an A/J phenotype for Xbp1 and Socs3 gene expression. Identification of the genes for these eQTLs will lead to a better understanding of the genetic factors responsible for NAFLD and potentially other hepatic diseases. Liver samples from eight-week-old AJ and C57BL6J males fed a High Fat High Calorie diet.
Project description:X-box binding protein 1 (XBP1) is a key component of the unfolded protein response (UPR) and plays important roles in the pathogenesis of nonalcoholic fatty liver diseases (NAFLD). Mice with liver-specific XBP1 deletion developed great liver injury and fibrosis in a dietary model of NAFLD. This project is to investigate hepatocyte-specific transcriptome profiling in XBP1-deficient mice fed a high fat sugar diet.
Project description:Xbp1 is an important regulator of unfolded protein response and lipid metabolism. Its dyregulation has been associcated in human NASH. Feeding a high fat diet with fructose/sucrose to mice causes progressive, fibrosing steatohepatitis. This study is to use RNA-Seq to identify differentially expressed genes in hepatic Xbp1 deficient mice livers fed with a high fat diet compared to controls.
Project description:The C57BL/6J mouse model develops obesity and pre-diabetes when fed a high-fat diet. In this experiment, DNA methylation was assessed globally at specific CpG sites in liver tissue from mice receiving high-fat diet (45E% from fat) for 13 weeks (Control) or high-fat diet supplemented with 20% (w/w) of freeze-dried lingonberries (n=4). Our findings show that lingonberries prevent development of high-fat induced obesity, hepatic steatosis and low-grade inflammation, and the DNA was hypermethylated in mice receiving lingonberries compared to control. Genome wide hepatic DNA methylation comparison between mice fed high-fat diet with or without a lingonberry supplement (n=4/group).
Project description:Comparison of RNA expression in liver and gonadal fat from female adipose-specific protein kinase C epsilon knockout mice and littermate controls, fed a high fat diet
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:We previously demonstrated that antisense oligonucleotide (ASO)-mediated knockdown of Mboat7, the gene encoding Membrane Bound O-Acyltransferase 7, in the liver and adipose tissue of mice promoted high fat diet-induced hepatic steatosis, hyperinsulinemia, and systemic insulin resistance. Thereafter, other groups showed that hepatocyte-specific genetic deletion of Mboat7 promoted striking fatty liver and NAFLD progression in mice but does not alter insulin sensitivity, suggesting the potential for cell autonomous roles. Here, we show that MBOAT7 function in adipocytes contributes to diet-induced metabolic disturbances including hyperinsulinemia and systemic insulin resistance. We generated floxed Mboat7 mice and created hepatocyte- and adipocyte-specific knockout mice using Cre-recombinase mice under the control of the albumin and adiponectin promoter, respectively. After chow and high fat diet feeding (60% kCal fat), mice were subjected to metabolic phenotyping and tissues to molecular workup and analysis. Here, we show that MBOAT7 function in adipocytes contributes to diet-induced metabolic disturbances including hyperinsulinemia and systemic insulin resistance. The expression of Mboat7 in white adipose tissue closely correlates with diet-induced obesity across a panel of ~100 inbred strains of mice fed a high fat/high sucrose diet. Moreover, we found that adipocyte-specific genetic deletion of Mboat7 is sufficient to promote hyperinsulinemia, systemic insulin resistance, and mild fatty liver. Unlike in the liver, where Mboat7 plays a relatively minor role in maintaining arachidonic acid (AA)-containing PI pools, Mboat7 is the major source of AA-containing PI pools in adipose tissue. Our data demonstrate that MBOAT7 is a critical regulator of adipose tissue PI homeostasis, and adipocyte MBOAT7-driven PI biosynthesis is closely linked to hyperinsulinemia and insulin resistance in mice.