HCV 3a core protein increases lipid droplet cholesteryl ester content via a mechanism dependent on sphingolipid biosynthesis

PLoS One. 2014 Dec 18;9(12):e115309. doi: 10.1371/journal.pone.0115309. eCollection 2014.

Abstract

Hepatitis C virus (HCV) infected patients often develop steatosis and the HCV core protein alone can induce this phenomenon. To gain new insights into the pathways leading to steatosis, we performed lipidomic profiling of HCV core protein expressing-Huh-7 cells and also assessed the lipid profile of purified lipid droplets isolated from HCV 3a core expressing cells. Cholesteryl esters, ceramides and glycosylceramides, but not triglycerides, increased specifically in cells expressing the steatogenic HCV 3a core protein. Accordingly, inhibitors of cholesteryl ester biosynthesis such as statins and acyl-CoA cholesterol acyl transferase inhibitors prevented the increase of cholesteryl ester production and the formation of large lipid droplets in HCV core 3a-expressing cells. Furthermore, inhibition of de novo sphingolipid biosynthesis by myriocin - but not of glycosphingolipid biosynthesis by miglustat - affected both lipid droplet size and cholesteryl ester level. The lipid profile of purified lipid droplets, isolated from HCV 3a core-expressing cells, confirmed the particular increase of cholesteryl ester. Thus, both sphingolipid and cholesteryl ester biosynthesis are affected by the steatogenic core protein of HCV genotype 3a. These results may explain the peculiar lipid profile of HCV-infected patients with steatosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Cholesterol Esters / metabolism*
  • Hepacivirus / metabolism*
  • Humans
  • Lipid Droplets / metabolism*
  • Sphingolipids / biosynthesis
  • Sphingolipids / metabolism*
  • Viral Core Proteins / metabolism*

Substances

  • Cholesterol Esters
  • Sphingolipids
  • Viral Core Proteins

Grants and funding

This work was supported by the University of Geneva; by the Swiss National Science Foundation (SNSF, http://www.snf.ch); the NCCR Chemical Biology and SystemsX.ch (http://www.systemsx.ch) evaluated by the SNSF to HR; by the SNSF (grants 314730-130498 and 314730-146991) to FN; by the FLAGS Foundation to SC and FN; and by the Balsells Fellowship Program to EOP. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.