Lipogenic transcription factor ChREBP mediates fructose-induced metabolic adaptations to prevent hepatotoxicity

J Clin Invest. 2017 Jun 30;127(7):2855-2867. doi: 10.1172/JCI89934. Epub 2017 Jun 19.

Abstract

Epidemiologic and animal studies implicate overconsumption of fructose in the development of nonalcoholic fatty liver disease, but the molecular mechanisms underlying fructose-induced chronic liver diseases remain largely unknown. Here, we have presented evidence supporting the essential function of the lipogenic transcription factor carbohydrate response element-binding protein (ChREBP) in mediating adaptive responses to fructose and protecting against fructose-induced hepatotoxicity. In WT mice, a high-fructose diet (HFrD) activated hepatic lipogenesis in a ChREBP-dependent manner; however, in Chrebp-KO mice, a HFrD induced steatohepatitis. In Chrebp-KO mouse livers, a HFrD reduced levels of molecular chaperones and activated the C/EBP homologous protein-dependent (CHOP-dependent) unfolded protein response, whereas administration of a chemical chaperone or Chop shRNA rescued liver injury. Elevated expression levels of cholesterol biosynthesis genes in HFrD-fed Chrebp-KO livers were paralleled by an increased nuclear abundance of sterol regulatory element-binding protein 2 (SREBP2). Atorvastatin-mediated inhibition of hepatic cholesterol biosynthesis or depletion of hepatic Srebp2 reversed fructose-induced liver injury in Chrebp-KO mice. Mechanistically, we determined that ChREBP binds to nuclear SREBP2 to promote its ubiquitination and destabilization in cultured cells. Therefore, our findings demonstrate that ChREBP provides hepatoprotection against a HFrD by preventing overactivation of cholesterol biosynthesis and the subsequent CHOP-mediated, proapoptotic unfolded protein response. Our findings also identified a role for ChREBP in regulating SREBP2-dependent cholesterol metabolism.

MeSH terms

  • Animals
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Chemical and Drug Induced Liver Injury / genetics
  • Chemical and Drug Induced Liver Injury / metabolism*
  • Chemical and Drug Induced Liver Injury / pathology
  • Cholesterol / genetics
  • Cholesterol / metabolism
  • Dietary Carbohydrates / adverse effects*
  • Dietary Carbohydrates / pharmacology
  • Fructose / adverse effects*
  • Fructose / pharmacology
  • Liver / injuries
  • Liver / metabolism*
  • Liver / pathology
  • Mice
  • Mice, Knockout
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Protein Binding / drug effects
  • Protein Binding / genetics
  • Sterol Regulatory Element Binding Protein 2 / genetics
  • Sterol Regulatory Element Binding Protein 2 / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Unfolded Protein Response / drug effects*
  • Unfolded Protein Response / genetics

Substances

  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Dietary Carbohydrates
  • Mlxipl protein, mouse
  • Nuclear Proteins
  • Srebf2 protein, mouse
  • Sterol Regulatory Element Binding Protein 2
  • Transcription Factors
  • Fructose
  • Cholesterol