Screening compounds against HCV based on MAVS/IFN-β pathway in a replicon model

Area of Science:

• Virology
• Biochemistry
• Assay Development

Background:

• Hepatitis C virus (HCV) infection is a significant global health concern.
• Developing sensitive assays is crucial for identifying effective antiviral compounds.
• The NS3/4A protease is a key target for HCV drug development.

Purpose of the Study:

• To develop a sensitive and quantitative reporter assay for screening anti-HCV compounds.
• To utilize the NS3/4A protease activity as a readout for drug screening.

Main Methods:

• A reporter system was engineered using enhanced yellow fluorescent protein (eYFP)-mitochondrial antiviral signaling protein (MAVS) and secreted placental alkaline phosphatase (SEAP).
• Proteolytic cleavage of eYFP-MAVS by HCV NS3/4A protease was monitored via SEAP activity using chemiluminescence.
• Subcellular localization and protein levels were confirmed using fluorescence microscopy and Western blotting.

Main Results:

• HCV NS3/4A protease cleavage of eYFP-MAVS inhibited interferon-β promoter activation, leading to decreased SEAP activity.
• The reduction in SEAP activity demonstrated a dose-dependent relationship with active NS3/4A protease.
• The assay successfully detected the anti-HCV activity of interferon-α and cyclosporine A.

Conclusions:

• The developed reporter system is a sensitive and quantitative tool for identifying HCV inhibitors.
• This assay provides a novel platform for the efficient screening of potential anti-HCV drugs.