Endocannabinoid CB1 Antagonists Inhibit Hepatitis C Virus Production, Providing a Novel Class of Antiviral Host-Targeting Agents

J Gen Virol. 2014 Nov;95(Pt 11):2468-2479. doi: 10.1099/vir.0.067231-0. Epub 2014 Jul 22.

Abstract

Direct-acting antivirals have significantly improved treatment outcomes in chronic hepatitis C (CHC), but side effects, drug resistance and cost mean that better treatments are still needed. Lipid metabolism is closely linked with hepatitis C virus (HCV) replication, and endocannabinoids are major regulators of lipid homeostasis. The cannabinoid 1 (CB1) receptor mediates these effects in the liver. We have previously shown upregulation of CB1 receptors in the livers of patients with CHC, and in a HCV cell-culture model. Here, we investigated whether CB1 blockade inhibited HCV replication. The antiviral effect of a CB1 antagonist, N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251), was examined in HCV strain JFH1 cell-culture and subgenomic replicon models. The effects on the expression of genes involved in lipid metabolism were also measured. CB1 short hairpin RNA (shRNA) was used to confirm that the effects were specific for the cannabinoid receptor. Treatment with AM251 strongly inhibited HCV RNA (~70 %), viral protein (~80 %), the production of new virus particles (~70 %) and virus infectivity (~90 %). As expected, AM251 reduced the expression of pro-lipogenic genes (SREBP-1c, FASN, SCD1 and ACC1) and stimulated genes promoting lipid oxidation (CPT1 and PPARα). This effect was mediated by AMP-activated protein kinase (AMPK). Stable CB1 knockdown of cells infected with HCV showed reduced levels of HCV RNA compared with controls. Thus, reduced CB1 signalling inhibits HCV replication using either pharmacological inhibitors or CB1 shRNA. This may be due, at least in part, to reduced lipogenesis, mediated by AMPK activation. We suggest that CB1 antagonists may represent an entirely new class of drug with activity against HCV.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases / metabolism
  • Antiviral Agents / pharmacology*
  • Cannabinoid Receptor Antagonists / pharmacology*
  • Cell Line
  • Gene Knockdown Techniques
  • Hepacivirus / drug effects*
  • Hepacivirus / genetics
  • Hepacivirus / physiology*
  • Humans
  • Lipid Metabolism / drug effects
  • Lipogenesis / drug effects
  • Models, Biological
  • Piperidines / pharmacology
  • Pyrazoles / pharmacology
  • RNA, Small Interfering / genetics
  • RNA, Viral / genetics
  • RNA, Viral / metabolism
  • Receptor, Cannabinoid, CB1 / antagonists & inhibitors*
  • Receptor, Cannabinoid, CB1 / genetics
  • Viral Proteins / genetics
  • Viral Proteins / metabolism
  • Virion / drug effects
  • Virion / genetics
  • Virion / physiology
  • Virus Replication / drug effects

Substances

  • Antiviral Agents
  • Cannabinoid Receptor Antagonists
  • Piperidines
  • Pyrazoles
  • RNA, Small Interfering
  • RNA, Viral
  • Receptor, Cannabinoid, CB1
  • Viral Proteins
  • AM 251
  • AMP-Activated Protein Kinases