Apolipoprotein E on hepatitis C virion facilitates infection through interaction with low-density lipoprotein receptor

Virology. 2009 Nov 10;394(1):99-108. doi: 10.1016/j.virol.2009.08.037. Epub 2009 Sep 13.

Abstract

Hepatitis C virus (HCV) infection is a major cause of liver disease. HCV associates with host apolipoproteins and enters hepatocytes through complex processes involving some combination of CD81, claudin-1, occludin, and scavenger receptor BI. Here we show that infectious HCV resembles very low density lipoprotein (VLDL) and that entry involves co-receptor function of the low-density lipoprotein receptor (LDL-R). Blocking experiments demonstrate that beta-VLDL itself or anti-apolipoprotein E (apoE) antibody can block HCV entry. Knockdown of the LDL-R by treatment with 25-hydroxycholesterol or siRNA ablated ligand uptake and reduced HCV infection of cells, whereas infection was rescued upon cell ectopic LDL-R expression. Analyses of gradient-fractionated HCV demonstrate that apoE is associated with HCV virions exhibiting peak infectivity and dependence upon the LDL-R for cell entry. Our results define the LDL-R as a cooperative HCV co-receptor that supports viral entry and infectivity through interaction with apoE ligand present in an infectious HCV/lipoprotein complex comprising the virion. Disruption of HCV/LDL-R interactions by altering lipoprotein metabolism may therefore represent a focus for future therapy.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apolipoproteins E / isolation & purification
  • Apolipoproteins E / metabolism*
  • Gene Knockdown Techniques
  • Hepacivirus / chemistry
  • Hepacivirus / physiology*
  • Humans
  • Protein Binding
  • Receptors, LDL / antagonists & inhibitors
  • Receptors, LDL / metabolism*
  • Receptors, Virus / antagonists & inhibitors
  • Receptors, Virus / metabolism*
  • Virus Attachment*
  • Virus Internalization*

Substances

  • Apolipoproteins E
  • Receptors, LDL
  • Receptors, Virus