Project description:Dysregulated glucose homeostasis and lipid accumulation characterize non-alcoholic fatty liver disease (NAFLD), but underlying mechanisms are obscure. We report here that Krüppel-like factor 6 (KLF6), a ubiquitous transcription factor that promotes adipocyte differentiation, also provokes the metabolic abnormalities of NAFLD. Mice with either hepatocyte-specific knockdown of KLF6 (DeltaHepKlf6) or global KLF6 heterozygosity (Klf6 +/-) have reduced body fat content and improved glucose and insulin tolerance. Mice with KLF6 depletion, compared to wild type mice, are protected from high fat diet-induced steatosis. Three mice with a hepatocyte-specific knockdown of KLF6 (DeltaHepKlf6) on high fat diet and 3 littermate controls on the same diet were sacrificed after 8 weeks of diet. Liver tissue was preserved in RNAlater® (Ambion, Austin, TX). RNA was isolated from liver tissue and homogenized in TRIzol® reagent (Invitrogen, Carlsbad, CA). In order to identify potential KLF6 targets that contributed to changes in glucose- and lipid-metabolism, we performed an Affymetrix Exon1 S.T. Genearray® (Affymetrix, Santa Clara, CA).
Project description:Dysregulated glucose homeostasis and lipid accumulation characterize non-alcoholic fatty liver disease (NAFLD), but underlying mechanisms are obscure. We report here that Krüppel-like factor 6 (KLF6), a ubiquitous transcription factor that promotes adipocyte differentiation, also provokes the metabolic abnormalities of NAFLD. Mice with either hepatocyte-specific knockdown of KLF6 (DeltaHepKlf6) or global KLF6 heterozygosity (Klf6 +/-) have reduced body fat content and improved glucose and insulin tolerance. Mice with KLF6 depletion, compared to wild type mice, are protected from high fat diet-induced steatosis.
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.
Project description:We investigated the plasma and liver proteome changes in liver fibrosis in mice induced by hepatocyte-specific knockout of nicotinamide phosphoribosyltransferase (Nampt) upon a low-methionine, choline-free 60% high-fat (MCD) diet at multiple time points. We also investigated whether supplementation with nicotinamide riboside could alleviate liver injury and how the liver proteome changes upon NR supplementation.
Project description:Adult PPARg floxed male and female mice were fed a high fat diet (HFD) for 16 weeks to induce obesity. Half of these mice were then injected with AAV8-TBG-Cre to knockout PPARg in hepatocytes. The remaining half were injected with AAV8-TBG-Null to generate control mice. After two weeks, mice fed the HFD were either maintained on this diet or switched to a high fat, high cholestrol, high fructose (HFCF) diet for an additional 16 weeks. This study was designed to examine whether the loss of hepatocyte PPARg in mice with established obesity would alter the liver transcriptomics in a PPARg dependent manner when the mice are fed a HFD or a HFCF diet.
Project description:The ER-resident prote in fat-inducing transcript 2 (FIT2) catalyzes acyl-CoA cleavage in vitro, and in cells is required for endoplasmic reticulum (ER)homeostasis and normal lipid storage. The gene encoding FIT2 is essential for viability of mice and worms. Whether FIT2 acts as anacyl-CoA diphosphatase in vivo and how this activity affects liver, where the protein was discovered,is unknown. Here, we report that hepatocyte-specific Fitm2 knockout (FIT2-LKO) mice exhibited elevated acyl-CoA levels, ER stress, and signs of liver injury. FIT2-LKO mice had increased triglyceride (TG) content in liver when fed a chow diet, compared with control littermates due in part to impaired secretion of TG-rich lipoproteins and reduced capacity for fatty acid oxidation. Challenging FIT2-LKO mice with a high-fat diet to increase FIT2 acyl-CoA substrates worsened hepatic ER stress and liver injury, yet unexpectedly reversed the steatosis phenotype, similar to what is observed in FIT2-deficient cells loaded with fatty acids. Our findings show that FIT2 acts as anacyl-CoA diphosphatase in vivo and is crucial for normal hepatocyte function and ER homeostasis in murine liver
Project description:Analysis of subcutaneous adipose tissue (IWAT) from Yin Yang 1 brown fat specific knockout mice fed a high fat diet for 2 weeks. The goal was to identify a gene signature of IWAT browning in YY1 mutant mice. Control mice YY1flox/flox versus YY1flox/flox; Ucp1Cre were fed a high fat diet for 2 weeks
Project description:Tmem120a was shown to be important for adipocytes differentiation. Here we analyze gene expression in suncutaneous adipose tissue form Tmem120a fat-specific knockout mouse on high fat vs low fat diet.
Project description:Analysis of brown adipose tissue from Yin Yang 1 (YY1) brown fat specific knockout mice fed a high fat diet for 3 months. YY1 deficiency in brown adipose tissue leads to strong thermogenic deficiency. The goal was to identify the genes controlled by YY1 responsible of brown fat defective function. Control mice YY1flox/flox versus YY1flox/flox; Ucp1Cre were fed a high fat diet for 3 months
