High-Throughput Activity Assay for Screening Inhibitors of the SARS-CoV-2 Mac1 Macrodomain
Morgan Dasovich, Junlin Zhuo, Jack A. Goodman, Ajit G. Thomas, Robert Lyle McPherson, Aravinth Kumar Jayabalan, Veronica F. Busa, Shang-Jung Cheng, Brennan A. Murphy, Karli R. Redinger, Yousef M. Alhammad, Anthony R. Fehr, Takashi Tsukamoto, Barbara S. Slusher, Jürgen Bosch, Huijun Wei, Anthony K. L. Leung
Abstract
Macrodomains are a class of conserved ADP-ribosylhydrolases expressed by viruses of pandemic concern, including coronaviruses and alphaviruses. Viral macrodomains are critical for replication and virus-induced pathogenesis; therefore, these enzymes are a promising target for antiviral therapy. However, no potent or selective viral macrodomain inhibitors currently exist, in part due to the lack of a high-throughput assay for this class of enzymes. Here we developed a high-throughput ADP-ribosylhydrolase assay using the SARS-CoV-2 macrodomain Mac1. We performed a pilot screen that identified dasatinib and dihydralazine as ADP-ribosylhydrolase inhibitors. Importantly, dasatinib inhibits SARS-CoV-2 and MERS-CoV Mac1 but not the closest human homologue, MacroD2. Our study demonstrates the feasibility of identifying selective inhibitors based on ADP-ribosylhydrolase activity, paving the way for the screening of large compound libraries to identify improved macrodomain inhibitors and to explore their potential as antiviral therapies for SARS-CoV-2 and future viral threats.