A VSV-based assay quantifies coronavirus Mpro/3CLpro/Nsp5 main protease activity and chemical inhibition

Commun Biol. 2022 Apr 27;5(1):391. doi: 10.1038/s42003-022-03277-0.

Abstract

Protease inhibitors are among the most powerful antiviral drugs. However, for SARS-CoV-2 only a small number of protease inhibitors have been identified thus far and there is still a great need for assays that efficiently report protease activity and inhibition in living cells. Here, we engineer a safe VSV-based system to report both gain- and loss-of-function of coronavirus main protease (Mpro/3CLpro/Nsp5) activity in living cells. We use SARS-CoV-2 3CLpro in this system to confirm susceptibility to known inhibitors (boceprevir, GC376, PF-00835231, and PF-07321332/nirmatrelvir) and reevaluate other reported inhibitors (baicalein, ebselen, carmofur, ethacridine, ivermectin, masitinib, darunavir, and atazanavir). Moreover, we show that the system can be adapted to report both the function and the chemical inhibition of proteases from different coronavirus species as well as from distantly related viruses. Together with the fact that live cell assays also reflect compound permeability and toxicity, we anticipate that this system will be useful for both identification and optimization of additional coronavirus protease inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • COVID-19*
  • Cysteine Endopeptidases*
  • Humans
  • Indoles
  • Lactams
  • Leucine
  • Nitriles
  • Peptide Hydrolases
  • Proline
  • Protease Inhibitors / pharmacology
  • Pyrrolidinones
  • SARS-CoV-2
  • Viral Proteins / chemistry

Substances

  • Indoles
  • Lactams
  • Nitriles
  • Protease Inhibitors
  • Pyrrolidinones
  • Viral Proteins
  • nirmatrelvir
  • Proline
  • Peptide Hydrolases
  • Cysteine Endopeptidases
  • Leucine
  • lufotrelvir