title: Inhibition of hepatitis C virus translation and subgenomic replication by siRNAs directed against highly conserved HCV sequence and cellular HCV cofactors.
abstract: OBJECTIVE
  Small interfering RNAs (siRNAs) are an efficient tool to specifically inhibit gene expression by RNA interference. Since hepatitis C virus (HCV) replicates in the cytoplasm of liver cells without integration into the host genome, RNA-directed antiviral strategies are likely to successfully block the HCV replication cycle. Additional benefit might arise from inhibition of cellular cofactors of HCV replication, such as proteasome alpha-subunit 7 (PSMA7) or Hu antigen R (HuR).
  
  
  METHODS
  In this study, we investigated direct and cofactor-mediated inhibition of HCV by a panel of DNA-based retroviral vectors expressing siRNAs against highly conserved HCV sequences or the putative HCV cofactors PSMA7 and HuR. Effects were determined in HCV IRES-mediated translation assays and subgenomic HCV replicon cells.
  
  
  RESULTS
  PSMA7- and HuR-directed siRNAs successfully inhibited expression of the endogenous genes, and PSMA7 and HuR silencing significantly diminished HCV replicon RNA and NS5B protein levels. HCV-directed siRNAs substantially inhibited HCV IRES-mediated translation and subgenomic HCV replication. Combinations of PSMA7- and HuR-directed siRNAs with HCV-directed siRNAs revealed additive HCV RNA inhibitory effects in monocistronic replicon cells.
  
  
  CONCLUSIONS
  A dual approach of direct- and cofactor-mediated inhibition of HCV replication might avoid selection of mutants and thereby become a powerful strategy against HCV.
authors.affiliation: Department of Gastroenterology, Hepatology and Endocrinology, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany.
authors.forename: Mortimer
authors.initials: M
authors.lastname: Korf
authors.forename: Dominik
authors.initials: D
authors.lastname: Jarczak
authors.forename: Carmela
authors.initials: C
authors.lastname: Beger
authors.forename: Michael P
authors.initials: MP
authors.lastname: Manns
authors.forename: Martin
authors.initials: M
authors.lastname: Krüger
mesh_terms: D000954:Antigens, Surface / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D003546:Cysteine Endopeptidases / Q000187:drug effects* / Q000378:metabolism; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D005814:Genes, Viral / Q000187:drug effects; D016679:Genome, Viral; D016174:Hepacivirus / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D008099:Liver / Q000166:cytology / Q000378:metabolism / Q000821:virology; D010957:Plasmids; D046988:Proteasome Endopeptidase Complex; D014176:Protein Biosynthesis / Q000187:drug effects*; D021122:Protein Subunits / Q000037:antagonists & inhibitors* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology*; D012367:RNA, Viral / Q000037:antagonists & inhibitors / Q000235:genetics; D016601:RNA-Binding Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014162:Transfection; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D015678:Viral Structural Proteins / Q000235:genetics; D014779:Virus Replication / Q000187:drug effects* / Q000235:genetics; D012324:RNA-Dependent RNA Polymerase
chemical_list: D000954:Antigens, Surface; D003546:Cysteine Endopeptidases; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D046988:Proteasome Endopeptidase Complex; D021122:Protein Subunits; D034741:RNA, Small Interfering; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D017361:Viral Nonstructural Proteins; D015678:Viral Structural Proteins; C098770:ELAVL1 protein, human; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase; C488662:PSMA7 protein, human