Cellular cholesterol accumulation modulates high fat high sucrose (HFHS) diet-induced ER stress and hepatic inflammasome activation in the development of non-alcoholic steatohepatitis

Biochim Biophys Acta. 2016 Jul;1861(7):594-605. doi: 10.1016/j.bbalip.2016.04.005. Epub 2016 Apr 14.


Non-alcoholic steatohepatitis (NASH), is the form of non-alcoholic fatty liver disease posing risk to progress into serious long term complications. Human and pre-clinical models implicate cellular cholesterol dysregulation playing important role in its development. Mouse model studies suggest synergism between dietary cholesterol and fat in contributing to NASH but the mechanisms remain poorly understood. Our laboratory previously reported the primary importance of hepatic endoplasmic reticulum cholesterol (ER-Chol) in regulating hepatic ER stress by comparing the responses of wild type, Ldlr-/-xLcat+/+ and Ldlr-/-xLcat-/- mice, to a 2% high cholesterol diet (HCD). Here we further investigated the roles of ER-Chol and ER stress in HFHS diet-induced NASH using the same strains. With HFHS diet feeding, both WT and Ldlr-/-xLcat+/+ accumulate ER-Chol in association with ER stress and inflammasome activation but the Ldlr-/-xLcat-/- mice are protected. By contrast, all three strains accumulate cholesterol crystal, in correlation with ER-Chol, albeit less so in Ldlr-/-xLcat-/- mice. By comparison, HCD feeding per se (i) is sufficient to promote steatosis and activate inflammasomes, and (ii) results in dramatic accumulation of cholesterol crystal which is linked to inflammasome activation in Ldlr-/-xLcat-/- mice, independent of ER-Chol. Our data suggest that both dietary fat and cholesterol each independently promote steatosis, cholesterol crystal accumulation and inflammasome activation through distinct but complementary pathways. In vitro studies using palmitate-induced hepatic steatosis in HepG2 cells confirm the key roles by cellular cholesterol in the induction of steatosis and inflammasome activations. These novel findings provide opportunities for exploring a cellular cholesterol-focused strategy for treatment of NASH.

Keywords: Cholesterol crystal; ER cholesterol; ER stress; Inflammasome; LCAT knockout mice; NASH.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cholesterol, Dietary / adverse effects
  • Cholesterol, Dietary / metabolism*
  • Diet, High-Fat / adverse effects
  • Disease Models, Animal
  • Endoplasmic Reticulum Stress / drug effects*
  • Endoplasmic Reticulum Stress / genetics
  • Female
  • Gene Expression Regulation
  • Hep G2 Cells
  • Humans
  • Inflammasomes / drug effects
  • Inflammasomes / metabolism
  • Lecithin Cholesterol Acyltransferase Deficiency / genetics
  • Lecithin Cholesterol Acyltransferase Deficiency / metabolism
  • Lipid Metabolism / genetics
  • Liver / metabolism*
  • Liver / pathology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Non-alcoholic Fatty Liver Disease / etiology
  • Non-alcoholic Fatty Liver Disease / genetics*
  • Non-alcoholic Fatty Liver Disease / metabolism
  • Non-alcoholic Fatty Liver Disease / physiopathology
  • Oxidation-Reduction
  • Palmitic Acid / pharmacology
  • Phosphatidylcholine-Sterol O-Acyltransferase / genetics*
  • Phosphatidylcholine-Sterol O-Acyltransferase / metabolism
  • Receptors, LDL / deficiency
  • Receptors, LDL / genetics*
  • Signal Transduction


  • Cholesterol, Dietary
  • Inflammasomes
  • Receptors, LDL
  • Palmitic Acid
  • Phosphatidylcholine-Sterol O-Acyltransferase