Increased hepatic synthesis and dysregulation of cholesterol metabolism is associated with the severity of nonalcoholic fatty liver disease

Cell Metab. 2012 May 2;15(5):665-74. doi: 10.1016/j.cmet.2012.04.004.

Abstract

Nonalcoholic fatty liver disease (NAFLD) is associated with increased cardiovascular and liver-related mortality. NAFLD is characterized by both triglyceride and free cholesterol (FC) accumulation without a corresponding increment in cholesterol esters. The aim of this study was to evaluate the expression of cholesterol metabolic genes in NAFLD and relate these to disease phenotype. NAFLD was associated with increased SREBP-2 maturation, HMG CoA reductase (HMGCR) expression and decreased phosphorylation of HMGCR. Cholesterol synthesis was increased as measured by the circulating desmosterol:cholesterol ratio. miR-34a, a microRNA increased in NAFLD, inhibited sirtuin-1 with downstream dephosphorylation of AMP kinase and HMGCR. Cholesterol ester hydrolase was increased while ACAT-2 remained unchanged. LDL receptor expression was significantly decreased and similar in NAFLD subjects on or off statins. HMGCR expression was correlated with FC, histologic severity of NAFLD and LDL-cholesterol. These data demonstrate dysregulated cholesterol metabolism in NAFLD which may contribute to disease severity and cardiovascular risks.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adenylate Kinase / genetics
  • Adenylate Kinase / metabolism
  • Adult
  • Cardiovascular Diseases / genetics
  • Cardiovascular Diseases / metabolism
  • Case-Control Studies
  • Cholesterol / blood
  • Cholesterol / genetics*
  • Cholesterol / metabolism*
  • Cholesterol, LDL / genetics
  • Cholesterol, LDL / metabolism
  • Desmosterol / blood
  • Desmosterol / metabolism
  • Fatty Liver / blood
  • Fatty Liver / genetics
  • Fatty Liver / metabolism*
  • Female
  • Gene Expression
  • Humans
  • Hydroxymethylglutaryl CoA Reductases / genetics
  • Hydroxymethylglutaryl CoA Reductases / metabolism
  • Lipid Metabolism / genetics*
  • Liver / metabolism*
  • Male
  • MicroRNAs / genetics
  • MicroRNAs / metabolism
  • Middle Aged
  • Non-alcoholic Fatty Liver Disease
  • Phenotype
  • Phosphorylation / genetics
  • Receptors, LDL / genetics
  • Receptors, LDL / metabolism
  • Sirtuin 1 / genetics
  • Sirtuin 1 / metabolism
  • Sterol Esterase / genetics
  • Sterol Esterase / metabolism
  • Sterol O-Acyltransferase / genetics
  • Sterol O-Acyltransferase / metabolism
  • Sterol Regulatory Element Binding Protein 2 / genetics
  • Sterol Regulatory Element Binding Protein 2 / metabolism
  • Up-Regulation

Substances

  • Cholesterol, LDL
  • MIRN34 microRNA, human
  • MicroRNAs
  • Receptors, LDL
  • SREBF2 protein, human
  • Sterol Regulatory Element Binding Protein 2
  • Desmosterol
  • Cholesterol
  • HMGCR protein, human
  • Hydroxymethylglutaryl CoA Reductases
  • Sterol O-Acyltransferase
  • sterol O-acyltransferase 2
  • Adenylate Kinase
  • Sterol Esterase
  • SIRT1 protein, human
  • Sirtuin 1