Impaired SUMOylation of nuclear receptor LRH-1 promotes nonalcoholic fatty liver disease

J Clin Invest. 2017 Feb 1;127(2):583-592. doi: 10.1172/JCI85499. Epub 2017 Jan 17.

Abstract

Hepatic steatosis is caused by metabolic imbalances that could be explained in part by an increase in de novo lipogenesis that results from increased sterol element binding protein 1 (SREBP-1) activity. The nuclear receptor liver receptor homolog 1 (LRH-1) is an important regulator of intermediary metabolism in the liver, but its role in regulating lipogenesis is not well understood. Here, we have assessed the contribution of LRH-1 SUMOylation to the development of nonalcoholic fatty liver disease (NAFLD). Mice expressing a SUMOylation-defective mutant of LRH-1 (LRH-1 K289R mice) developed NAFLD and early signs of nonalcoholic steatohepatitis (NASH) when challenged with a lipogenic, high-fat, high-sucrose diet. Moreover, we observed that the LRH-1 K289R mutation induced the expression of oxysterol binding protein-like 3 (OSBPL3), enhanced SREBP-1 processing, and promoted de novo lipogenesis. Mechanistically, we demonstrated that ectopic expression of OSBPL3 facilitates SREBP-1 processing in WT mice, while silencing hepatic Osbpl3 reverses the lipogenic phenotype of LRH-1 K289R mice. These findings suggest that compromised SUMOylation of LRH-1 promotes the development of NAFLD under lipogenic conditions through regulation of OSBPL3.

MeSH terms

  • Animals
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Dietary Carbohydrates / adverse effects
  • Dietary Carbohydrates / pharmacology
  • Dietary Fats / adverse effects
  • Dietary Fats / pharmacology
  • Lipogenesis*
  • Liver / metabolism*
  • Liver / pathology
  • Mice
  • Mice, Mutant Strains
  • Non-alcoholic Fatty Liver Disease / chemically induced
  • Non-alcoholic Fatty Liver Disease / genetics
  • Non-alcoholic Fatty Liver Disease / metabolism*
  • Non-alcoholic Fatty Liver Disease / pathology
  • Receptors, Cytoplasmic and Nuclear / genetics
  • Receptors, Cytoplasmic and Nuclear / metabolism*
  • Sterol Regulatory Element Binding Protein 1 / genetics
  • Sterol Regulatory Element Binding Protein 1 / metabolism
  • Sumoylation*

Substances

  • Carrier Proteins
  • Dietary Carbohydrates
  • Dietary Fats
  • Nr5a2 protein, mouse
  • Receptors, Cytoplasmic and Nuclear
  • Srebf1 protein, mouse
  • Sterol Regulatory Element Binding Protein 1