HCV IRES-mediated core expression in zebrafish

PLoS One. 2013;8(3):e56985. doi: 10.1371/journal.pone.0056985. Epub 2013 Mar 1.

Abstract

The lack of small animal models for hepatitis C virus has impeded the discovery and development of anti-HCV drugs. HCV-IRES plays an important role in HCV gene expression, and is an attractive target for antiviral therapy. In this study, we report a zebrafish model with a biscistron expression construct that can co-transcribe GFP and HCV-core genes by human hepatic lipase promoter and zebrafish liver fatty acid binding protein enhancer. HCV core translation was designed mediated by HCV-IRES sequence and gfp was by a canonical cap-dependent mechanism. Results of fluorescence image and in situ hybridization indicate that expression of HCV core and GFP is liver-specific; RT-PCR and Western blotting show that both core and gfp expression are elevated in a time-dependent manner for both transcription and translation. It means that the HCV-IRES exerted its role in this zebrafish model. Furthermore, the liver-pathological impact associated with HCV-infection was detected by examination of gene markers and some of them were elevated, such as adiponectin receptor, heparanase, TGF-β, PDGF-α, etc. The model was used to evaluate three clinical drugs, ribavirin, IFNα-2b and vitamin B12. The results show that vitamin B12 inhibited core expression in mRNA and protein levels in dose-dependent manner, but failed to impact gfp expression. Also VB12 down-regulated some gene transcriptions involved in fat liver, liver fibrosis and HCV-associated pathological process in the larvae. It reveals that HCV-IRES responds to vitamin B12 sensitively in the zebrafish model. Ribavirin did not disturb core expression, hinting that HCV-IRES is not a target site of ribavirin. IFNα-2b was not active, which maybe resulted from its degradation in vivo for the long time. These findings demonstrate the feasibility of the zebrafish model for screening of anti-HCV drugs targeting to HCV-IRES. The zebrafish system provides a novel evidence of using zebrafish as a HCV model organism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antiviral Agents / pharmacology
  • Biomarkers / metabolism
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Gene Expression Regulation, Viral / drug effects*
  • Genes, Reporter
  • Green Fluorescent Proteins
  • Hepacivirus / drug effects*
  • Hepacivirus / genetics*
  • Hepacivirus / growth & development
  • Hepatitis C / drug therapy*
  • Hepatitis C / virology
  • Host-Pathogen Interactions
  • Humans
  • Interferon alpha-2
  • Interferon-alpha / pharmacology
  • Larva / drug effects
  • Larva / virology
  • Liver / drug effects
  • Liver / virology
  • Mutant Chimeric Proteins / antagonists & inhibitors
  • Mutant Chimeric Proteins / genetics
  • Mutant Chimeric Proteins / metabolism
  • RNA, Messenger / antagonists & inhibitors*
  • RNA, Messenger / genetics
  • Recombinant Proteins / pharmacology
  • Ribavirin / pharmacology
  • Viral Core Proteins / antagonists & inhibitors
  • Viral Core Proteins / genetics*
  • Viral Core Proteins / metabolism
  • Vitamin B 12 / pharmacology
  • Zebrafish / virology*

Substances

  • Antiviral Agents
  • Biomarkers
  • Interferon alpha-2
  • Interferon-alpha
  • Mutant Chimeric Proteins
  • RNA, Messenger
  • Recombinant Proteins
  • Viral Core Proteins
  • Green Fluorescent Proteins
  • Ribavirin
  • Vitamin B 12

Grants and funding

This study was supported by The National Natural Science Foundation of China (No. 30772681), and National Science and Technology Major Special Project on Major New Drug Innovation (Item Number: 2012ZX09301002-001-021) grants. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.