Transcription factor Nrf2 regulates SHP and lipogenic gene expression in hepatic lipid metabolism

Am J Physiol Gastrointest Liver Physiol. 2010 Dec;299(6):G1211-21. doi: 10.1152/ajpgi.00322.2010. Epub 2010 Oct 7.

Abstract

Nuclear factor erythroid-2 related factor 2 (Nrf2) plays a pivotal role in cytoprotection against both endogenous and exogenous stresses. Here, we establish a novel molecular link between Nrf2, nuclear receptor small heterodimer partner (SHP; NROB2), lipogenic genes, and hepatic lipid homeostasis. Deletion of Nrf2 (Nrf2⁻(/)⁻) in mice resulted in a reduced liver weight, a decrease in fatty acid content of hepatic triacylglycerol, as well as concomitant increases in the levels of serum VLDL-triglyceride (TG), HDL cholesterol, and ketone bodies at 6 mo of age. Liver weight and hepatic TG content were consistently lower in Nrf2⁻(/)⁻ mice upon a high-fat challenge. This phenotype was accompanied by downregulation of genes in lipid synthesis and uptake and upregulation of genes in lipid oxidation in older Nrf2⁻(/)⁻ mice. Interestingly, SHP expression was induced with age in Nrf2(+/+) mice but decreased by Nrf2 deficiency. Forced expression and activation of Nrf2 by Nrf2 activators consistently induced SHP expression, and Nrf2 was identified as a novel activator of the SHP gene transcription. We also identified PPAR-γ, Fas, Scd1, and Srebp-1 as direct targets of Nrf2 activation. These findings provide evidence for a role of Nrf2 in the modulation of hepatic lipid homeostasis through transcriptional activation of SHP and lipogenic gene expression.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / genetics
  • Aging / physiology
  • Animals
  • Dietary Fats / metabolism
  • Gene Expression Regulation / physiology
  • Lipid Metabolism / physiology*
  • Lipogenesis / physiology*
  • Liver / anatomy & histology
  • Liver / metabolism*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • NF-E2-Related Factor 2 / genetics
  • NF-E2-Related Factor 2 / metabolism*
  • Organ Size
  • Receptors, Cytoplasmic and Nuclear / genetics
  • Receptors, Cytoplasmic and Nuclear / metabolism*
  • Triglycerides / metabolism
  • Weight Gain

Substances

  • Dietary Fats
  • NF-E2-Related Factor 2
  • Nfe2l2 protein, mouse
  • Receptors, Cytoplasmic and Nuclear
  • Triglycerides
  • nuclear receptor subfamily 0, group B, member 2