A phenothiazine urea derivative broadly inhibits coronavirus replication via viral protease inhibition

Katrina Forrestall; Eric S Pringle; Dane Sands; Brett A Duguay; Brett Farewell; Tekeleselassie Woldemariam; Darryl Falzarano; Ian Pottie; Craig McCormick; Sultan Darvesh

doi:10.1016/j.antiviral.2023.105758

A phenothiazine urea derivative broadly inhibits coronavirus replication via viral protease inhibition

Antiviral Res. 2023 Dec:220:105758. doi: 10.1016/j.antiviral.2023.105758. Epub 2023 Nov 24.

Affiliations

¹ Department of Medicine (Geriatric Medicine and Neurology) and Medical Neuroscience, Dalhousie University, 5850 College Street, Halifax, NS, Canada, B3H 4R2.
² Department of Microbiology & Immunology, Dalhousie University, 5850 College Street, Halifax, NS, Canada, B3H 4R2.
³ Vaccine and Infectious Disease Organization (VIDO), 120 Veterinary Road, Saskatoon, SK, Canada, S7N 5E3.
⁴ Vaccine and Infectious Disease Organization (VIDO), 120 Veterinary Road, Saskatoon, SK, Canada, S7N 5E3; Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK, Canada, S7N 5B4.
⁵ Department of Chemistry & Physics, Mount Saint Vincent University, 166 Bedford Highway, Halifax, NS, Canada, B3M 2J6; Department of Chemistry, Saint Mary's University, 923 Robbie Street, Halifax, NS, Canada, B3H 3C3.
⁶ Department of Medicine (Geriatric Medicine and Neurology) and Medical Neuroscience, Dalhousie University, 5850 College Street, Halifax, NS, Canada, B3H 4R2; Department of Chemistry & Physics, Mount Saint Vincent University, 166 Bedford Highway, Halifax, NS, Canada, B3M 2J6. Electronic address: [email protected].

PMID: 38008194
DOI: 10.1016/j.antiviral.2023.105758

Abstract

Coronavirus (CoV) replication requires efficient cleavage of viral polyproteins into an array of non-structural proteins involved in viral replication, organelle formation, viral RNA synthesis, and host shutoff. Human CoVs (HCoVs) encode two viral cysteine proteases, main protease (M^pro) and papain-like protease (PL^pro), that mediate polyprotein cleavage. Using a structure-guided approach, a phenothiazine urea derivative that inhibits both SARS-CoV-2 M^pro and PL^pro protease activity was identified. In silico docking studies also predicted the binding of the phenothiazine urea to the active sites of structurally similar M^pro and PL^pro proteases from distantly related alphacoronavirus, HCoV-229 E (229 E), and the betacoronavirus, HCoV-OC43 (OC43). The lead phenothiazine urea derivative displayed broad antiviral activity against all three HCoVs tested in cellulo. It was further demonstrated that the compound inhibited 229 E and OC43 at an early stage of viral replication, with diminished formation of viral replication organelles, and the RNAs that are made within them, as expected following viral protease inhibition. These observations suggest that the phenothiazine urea derivative readily inhibits viral replication and may broadly inhibit proteases of diverse coronaviruses.

Keywords: Antiviral; Coronavirus; Main protease; Papain-like protease; Phenothiazine; SARS-CoV-2.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Antiviral Agents / chemistry
Antiviral Agents / pharmacology
Humans
Papain / chemistry
Peptide Hydrolases*
Phenothiazines / pharmacology
Protease Inhibitors / chemistry
SARS-CoV-2* / metabolism
Viral Proteases

Substances

Peptide Hydrolases
Papain
Viral Proteases
Phenothiazines
Protease Inhibitors
Antiviral Agents