Reporter gene expression from LTR-circles as tool to identify HIV-1 integrase inhibitors

Area of Science:

• Virology
• Drug Discovery
• Molecular Biology

Background:

• Early HIV-1 integrase inhibitors were identified using high-throughput screening and in vitro biochemical assays.
• Traditional assays measuring integrase catalytic activity lack cellular context, potentially missing crucial cellular processes and cofactors involved in HIV-1 DNA integration.
• Existing cell-based virus inhibition assays target multiple viral replication steps, hindering specific identification of integrase inhibitors.

Purpose of the Study:

• To develop a novel cellular screening assay for the specific identification of HIV-1 integrase inhibitors.
• To overcome the limitations of traditional biochemical assays by incorporating cellular processes.
• To enable high-throughput screening for compounds that specifically inhibit HIV-1 integrase activity.

Main Methods:

• A HIV-1 lentiviral vector encoding the enhanced green fluorescent protein (eGFP) reporter gene was utilized.
• The assay detects eGFP expression from extrachromosomal viral DNA (1- or 2-long terminal repeat circles) formed when integration is blocked by an integrase inhibitor.
• High-throughput flow cytometry measured eGFP expression, and an algorithm analyzed histograms to identify integrase inhibitors.

Main Results:

• The developed assay specifically identifies HIV-1 integrase inhibitors.
• eGFP expression levels correlated with the inhibition of integrase activity.
• The assay demonstrated amenability for high-throughput screening.

Conclusions:

• A novel, specific, and high-throughput compatible cellular assay for identifying HIV-1 integrase inhibitors has been established.
• This assay provides a more biologically relevant method for drug discovery compared to traditional biochemical assays.
• The assay facilitates the discovery of new therapeutic agents targeting HIV-1 integration.