Inhibition of hepatitis C virus translation and subgenomic replication by siRNAs directed against highly conserved HCV sequence and cellular HCV cofactors

• Published in: Journal of hepatology Vol. 43; no. 2; pp. 225 - 234
• Main Authors: Korf, Mortimer, Jarczak, Dominik, Beger, Carmela, Manns, Michael P., Krüger, Martin
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.08.2005; Elsevier
• Subjects: Antigens, Surface - metabolism; Biological and medical sciences; Blotting, Northern; Blotting, Western; Cysteine Endopeptidases - drug effects; Cysteine Endopeptidases - metabolism; ELAV Proteins; ELAV-Like Protein 1; Gene Expression Regulation, Viral - drug effects; Genes, Viral - drug effects; Genome, Viral; HCV; Hepacivirus - drug effects; Hepacivirus - physiology; Human viral diseases; Humans; HuR; In Vitro Techniques; Infectious diseases; Liver - cytology; Liver - metabolism; Liver - virology; Medical sciences; Plasmids; Proteasome Endopeptidase Complex; Protein Biosynthesis - drug effects; Protein Subunits - antagonists & inhibitors; Protein Subunits - metabolism; PSMA7; RNA, Small Interfering - pharmacology; RNA, Viral - antagonists & inhibitors; RNA, Viral - genetics; RNA-Binding Proteins - antagonists & inhibitors; RNA-Binding Proteins - metabolism; RNAi; siRNA; Transfection; UTR; Viral diseases; Viral hepatitis; Viral Nonstructural Proteins - antagonists & inhibitors; Viral Nonstructural Proteins - metabolism; Viral Structural Proteins - genetics; Virus Replication - drug effects; Virus Replication - genetics; UTR; RNAi; HuR; IRES; Rz; HCV; siRNA; tCD4; PSMA7; PTB; Hepatic disease; Cofactor; Infection; Virus; Viral disease; Digestive diseases; Replication; Flaviviridae; Hepatitis C virus; Hepacivirus; Viral hepatitis C
• ISSN: 0168-8278; 1600-0641
• DOI: 10.1016/j.jhep.2005.02.046

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 α-subunit 7 (PSMA7) or Hu antigen R (HuR). 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. 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. 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.