. 2023 Oct 11:105341.
doi: 10.1016/j.jbc.2023.105341. Online ahead of print. Reversible and irreversible inhibitors of coronavirus Nsp15 endoribonuclease
Jerry Chen 1 , Rabih Abou Farraj 2 , Daniel Limonta Velazquez 3 , Seyed Amir Tabatabaei Dakhili 4 , Evan M Kerek 1 , Ashim Bhattacharya 5 , Filip M Reformat 1 , Ola M Mabrouk 6 , Benjamin Brigant 7 , Tom A Pfeifer 8 , Mark T McDermott 6 , John R Ussher 4 , Tom C Hobman 9 , J N Mark Glover 2 , Basil P Hubbard 10
Affiliations
- PMID: 37832873
- DOI: 10.1016/j.jbc.2023.105341
The emergence of SARS-CoV-2, the causative agent of COVID-19, has resulted in the largest pandemic in recent history. Current therapeutic strategies to mitigate this disease have focused on the development of vaccines and on drugs that inhibit the viral 3CL protease or RNA-dependent RNA polymerase enzymes. A less-explored and potentially complementary drug target is Nsp15, a uracil-specific RNA endonuclease that shields coronaviruses and other nidoviruses from mammalian innate immune defenses. Here, we perform a high-throughput screen of over 100,000 small molecules to identify Nsp15 inhibitors. We characterize the potency, mechanism, selectivity, and predicted binding mode of five lead compounds. We show that one of these, IPA-3, is an irreversible inhibitor that might act via covalent modification of Cys residues within Nsp15. Moreover, we demonstrate that three of these inhibitors (Hexachlorophene, IPA-3, and CID5675221) block SARS-CoV-2 replication in cells at sub-toxic doses. This study provides a pipeline for the identification of Nsp15 inhibitors, and pinpoints lead compounds for further development against COVID-19 and related coronavirus infections.
Keywords: COVID-19; COVID-19 therapeutics; IPA-3; Nsp15; RNA endonucleases; SARS-CoV-2; coronaviruses; hexachlorophene; high-throughput chemical screen; immune evasion; nidoviruses; small-molecule inhibitors.