Up-regulation of the ATP-binding cassette transporter A1 inhibits hepatitis C virus infection

PLoS One. 2014 Mar 19;9(3):e92140. doi: 10.1371/journal.pone.0092140. eCollection 2014.

Abstract

Hepatitis C virus (HCV) establishes infection using host lipid metabolism pathways that are thus considered potential targets for indirect anti-HCV strategies. HCV enters the cell via clathrin-dependent endocytosis, interacting with several receptors, and virus-cell fusion, which depends on acidic pH and the integrity of cholesterol-rich domains of the hepatocyte membrane. The ATP-binding Cassette Transporter A1 (ABCA1) mediates cholesterol efflux from hepatocytes to extracellular Apolipoprotein A1 and moves cholesterol within cell membranes. Furthermore, it generates high-density lipoprotein (HDL) particles. HDL protects against arteriosclerosis and cardiovascular disease. We show that the up-regulation of ABCA1 gene expression and its cholesterol efflux function in Huh7.5 hepatoma cells, using the liver X receptor (LXR) agonist GW3965, impairs HCV infection and decreases levels of virus produced. ABCA1-stimulation inhibited HCV cell entry, acting on virus-host cell fusion, but had no impact on virus attachment, replication, or assembly/secretion. It did not affect infectivity or properties of virus particles produced. Silencing of the ABCA1 gene and reduction of the specific cholesterol efflux function counteracted the inhibitory effect of the GW3965 on HCV infection, providing evidence for a key role of ABCA1 in this process. Impaired virus-cell entry correlated with the reorganisation of cholesterol-rich membrane microdomains (lipid rafts). The inhibitory effect could be reversed by an exogenous cholesterol supply, indicating that restriction of HCV infection was induced by changes of cholesterol content/distribution in membrane regions essential for virus-cell fusion. Stimulation of ABCA1 expression by GW3965 inhibited HCV infection of both human primary hepatocytes and isolated human liver slices. This study reveals that pharmacological stimulation of the ABCA1-dependent cholesterol efflux pathway disrupts membrane cholesterol homeostasis, leading to the inhibition of virus-cell fusion and thus HCV cell entry. Therefore besides other beneficial roles, ABCA1 might represent a potential target for HCV therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter 1 / genetics*
  • ATP Binding Cassette Transporter 1 / metabolism
  • Benzoates / pharmacology
  • Benzylamines / pharmacology
  • Cell Cycle / drug effects
  • Cell Fusion
  • Cell Line, Tumor
  • Cholesterol / metabolism
  • HEK293 Cells
  • Hepacivirus / drug effects
  • Hepacivirus / pathogenicity
  • Hepacivirus / physiology*
  • Hepatitis C / genetics*
  • Hepatitis C / virology*
  • Hepatocytes / drug effects
  • Hepatocytes / metabolism
  • Hepatocytes / pathology
  • Hepatocytes / virology
  • Humans
  • Lipid Metabolism / drug effects
  • Lipid Metabolism / genetics
  • Liver / drug effects
  • Liver / metabolism
  • Liver / pathology
  • Liver / virology
  • Membrane Microdomains / metabolism
  • RNA, Viral / metabolism
  • Receptors, Virus / metabolism
  • Up-Regulation / drug effects
  • Up-Regulation / genetics*
  • Virion / drug effects
  • Virion / metabolism
  • Virus Attachment / drug effects
  • Virus Internalization / drug effects
  • Virus Replication / drug effects

Substances

  • ABCA1 protein, human
  • ATP Binding Cassette Transporter 1
  • Benzoates
  • Benzylamines
  • GW 3965
  • RNA, Viral
  • Receptors, Virus
  • Cholesterol

Grants and funding

SB was supported by the Doctoral Fellowship from the Italian Ministry of Science and Education and MY by the Postdoctoral Fellowship from the French Embassy in Japan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.