COVID-19: Assay Development, HTS and Drug Repurposing to identify potential therapeutics against SARS-CoV-2

National Center For Advancing Translational Sciences

Investigators

Abstract

During this past reporting period, NCATS began development of over a dozen novel assays to screen for potential therapeutic agents against SARS-CoV-2. Optimized assays were then screened against a panel of drug repurposing, clinical candidate and antiviral libraries that have been assembled at NCATS. These results have been made freely available to public with unprecedented speed through the NCATS OpenData Portal and through a number of preprint/journal publications. These assays include both virus (e.g. Spike protein) and host (e.g. ACE2, TMPRSS) targets, as well as BSL3 live SARS-CoV-2 virus infectivity assays accessed through research contracts. Many assays have been solely developed in-house at NCATS, while a number of others have been designed in collaboration with both intramural and extramural laboratories with subject area expertise. These collaborations include: 1. Cell-based SARS-CoV-2 ORF3a assay with Dr. Michael Lenardo (NIAID) 2. Recombinant SARS-CoV-2 nsp13 helicase assay with Dr. Robert Brosh (NIA) 3. Cell-based DNA topoisomerase assay with Dr. Yves Pommier (NCI) 4. Recombinant SARS-CoV-2 PLpro assay with Dr. Patricia Legler (Naval Research Laboratory) 5. Combination screening with Dr. Eugene Muratov (University of North Carolina) One such assay developed in-house was for the biochemical screening of recombinant TMPRSS2 suitable for high throughput applications to enable inhibitor discovery and profiling of FDA-approved therapeutics. The TMPRSS2 assay demonstrated sensitivity to quantify inhibition down to subnanomolar concentrations, and enabled assessment of inhibition of camostat, nafamostat, and gabexate (clinically approved agents in Japan), as well as FOY-251 (a camostat metabolite) and bromhexine hydrochloride, an FDA-approved mucolytic cough suppressant.