Innate immune responses in human hepatocyte-derived cell lines alter genotype 1 hepatitis E virus replication efficiencies

Sci Rep. 2016 May 27:6:26827. doi: 10.1038/srep26827.

Abstract

Hepatitis E virus (HEV) is a significant health problem in developing countries causing sporadic and epidemic forms of acute viral hepatitis. Hepatitis E is a self-limiting disease; however, chronic HEV infections are being reported in immunocompromised individuals. The disease severity is more during pregnancy with high mortality (20-25%), especially in third trimester. Early cellular responses after HEV infection are not completely understood. We analyzed innate immune responses associated with genotype-I HEV replication in human hepatoma cell lines (Huh7, Huh7.5 and HepG2/C3A) using HEV replicon system. These cells supported HEV replication with different efficiencies due to the cell type specific innate immune responses. HepG2/C3A cells were less supportive to HEV replication as compared to Huh7.5 and S10-3 cells. Reconstitution of the defective RIG-I and TLR3 signaling in Huh7.5 cells enabled them to induce higher level antiviral responses and restrict HEV replication, suggesting the involvement of both RIG-I and TLR3 in sensing HEV RNA and downstream activation of interferon regulatory factor 3 (IRF3) to generate antiviral responses. Inhibition of IRF3 mediated downstream responses in HepG2/C3A cells by pharmacological inhibitor BX795 significantly improved HEV replication efficiency implying the importance of this study in establishing a better cell culture system for future HEV studies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinoma, Hepatocellular / immunology*
  • Carcinoma, Hepatocellular / metabolism
  • Carcinoma, Hepatocellular / virology*
  • Cell Line, Tumor
  • DEAD Box Protein 58 / metabolism
  • Gene Expression
  • Hepatitis E virus / immunology*
  • Hepatocytes / immunology
  • Hepatocytes / metabolism
  • Hepatocytes / virology
  • Humans
  • Immunity, Innate*
  • Interferon Regulatory Factors / metabolism
  • Liver Neoplasms / immunology*
  • Liver Neoplasms / metabolism
  • Liver Neoplasms / virology*
  • Receptors, Immunologic
  • Receptors, Pattern Recognition / metabolism
  • Signal Transduction
  • Toll-Like Receptor 3 / metabolism
  • Transcriptome
  • Virus Replication*

Substances

  • Interferon Regulatory Factors
  • Receptors, Immunologic
  • Receptors, Pattern Recognition
  • TLR3 protein, human
  • Toll-Like Receptor 3
  • RIGI protein, human
  • DEAD Box Protein 58