A subset of dysregulated metabolic and survival genes is associated with severity of hepatic steatosis in obese Zucker rats

J Lipid Res. 2010 Mar;51(3):500-13. doi: 10.1194/jlr.M001966. Epub 2009 Sep 24.

Abstract

We aimed to characterize the primary abnormalities associated with fat accumulation and vulnerability to hepatocellular injury of obesity-related fatty liver. We performed functional analyses and comparative transcriptomics of isolated primary hepatocytes from livers of obese insulin-resistant Zucker rats (comprising mild to severe hepatic steatosis) and age-matched lean littermates, searching for novel genes linked to chronic hepatic steatosis. Of the tested genome, 1.6% was identified as steatosis linked. Overexpressed genes were mainly dedicated to primary metabolism (100%), signaling, and defense/acute phase (approximately 70%); detoxification, steroid, and sulfur metabolism (approximately 65%) as well as cell growth/proliferation and protein synthesis/transformation (approximately 70%) genes were downregulated. The overexpression of key genes involved in de novo lipogenesis, fatty acid and glycerolipid import and synthesis, as well as acetyl-CoA and cofactor provision was paralleled by enhanced hepatic lipogenesis and production of large triacylglycerol-rich VLDL. Greatest changes in gene expression were seen in those encoding the lipogenic malic enzyme (up to 7-fold increased) and cell-to-cell interacting cadherin 17 (up to 8-fold decreased). Among validated genes, fatty acid synthase, stearoyl-CoA desaturase 1, fatty acid translocase/Cd36, malic enzyme, cholesterol-7 alpha hydroxylase, cadherin 17, and peroxisome proliferator-activated receptor alpha significantly correlated with severity of hepatic steatosis. In conclusion, dysregulated expression of metabolic and survival genes accompany hepatic steatosis in obese insulin-resistant rats and may render steatotic hepatocytes more vulnerable to cell injury in progressive nonalcoholic fatty liver disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Proliferation
  • Cell Survival / genetics
  • Dyslipidemias / complications
  • Fatty Liver / complications
  • Fatty Liver / genetics*
  • Fatty Liver / metabolism*
  • Fatty Liver / pathology
  • Gene Expression Profiling
  • Insulin Resistance
  • Lipogenesis / genetics
  • Lipoproteins, VLDL / metabolism
  • Liver / metabolism*
  • Liver / pathology
  • Male
  • Obesity / complications*
  • Rats
  • Rats, Zucker
  • Steroids / metabolism
  • Triglycerides / metabolism

Substances

  • Lipoproteins, VLDL
  • Steroids
  • Triglycerides