Rapid luminescence-based screening method for SARS- CoV-2 inhibitors discovery

Area of Science:

• Virology
• Drug Discovery
• Biotechnology

Background:

• The COVID-19 pandemic highlighted the need for efficient antiviral drug screening. Conventional methods are slow and labor-intensive, especially for high-containment pathogens like SARS-CoV-2.
• Existing antiviral testing assays often require lengthy incubation periods and multiple manual steps, limiting throughput and speed.

Purpose of the Study:

• To design and validate a semi-automated drug screening platform for SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2).
• To develop a rapid assay utilizing a nano-luciferase reporter virus that bypasses virus inactivation and staining steps, enabling faster screening.
• To adapt the platform for high-throughput screening (HTS) meeting NIH criteria.

Main Methods:

• Utilized a stable A549 cell line expressing ACE2 and TMPRSS2 receptors and a recombinant SARS-CoV-2 nano-luciferase reporter virus.
• Employed multiple liquid handlers for semi-automated processing in 96- and 384-well plate formats.
• Assessed luminescence signal at 24 hours post-infection as a surrogate for viral replication, bypassing traditional 48-hour assays.

Main Results:

• The luminescence assay at 24 hours post-infection proved robust and reliable, correlating with established methods.
• Validation in 96- and 384-well plates demonstrated reproducible results with a Z factor ≥0.5 and coefficient of variation <20%.
• Screening of 240 compounds identified 48 potential hits, with 3 novel potent and non-toxic antiviral compounds confirmed.

Conclusions:

• The developed semi-automated platform enables rapid and reliable drug screening against SARS-CoV-2.
• The platform's efficiency and adaptability make it suitable for accelerating the discovery of novel antiviral therapeutics.
• This approach can be readily adapted for screening against other nano-luciferase reporter viruses.