Inhibition of phosphodiesterase 12 results in antiviral activity against several RNA viruses including SARS-CoV-2

Mark Thursz, Fouzia Sadiq, Julia A. Tree, Peter Karayiannis, David W.C. Beasley, Wanwissa Dejnirattisai, Juthathip Mongkolsapaya, Gavin Screaton, Matthew Wand, Michael J. Elmore, Miles W. Carroll, Ian Matthews, Howard Thomas

Research output: Contribution to journalArticlepeer-review


The 2,́5'- oligoadenylate synthetase (OAS) - ribonuclease L (RNAseL) - phosphodiesterase 12 (PDE12) pathway is an essential interferon-induced effector mechanism against RNA virus infection. Inhibition of PDE12 leads to selective amplification of RNAseL activity in infected cells. We aimed to investigate PDE12 as a potential pan-RNA virus antiviral drug target and develop PDE12 inhibitors that elicit antiviral activity against a range of viruses. A library of 18000 small molecules was screened for PDE12 inhibitor activity using a fluorescent probe specific for PDE12. The lead compounds (CO-17 or CO-63) were tested in cell-based antiviral assays using encephalomyocarditis virus (EMCV), hepatitis C virus (HCV), dengue virus (DENV), West Nile virus (WNV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in vitro. Cross reactivity of PDE12 inhibitors with other PDEs and in vivo toxicity were measured. In EMCV assays, CO-17 potentiated the effect of IFNα by 3 log10. The compounds were selective for PDE12 when tested against a panel of other PDEs and non-toxic at up to 42 mg kg−1 in rats in vivo. Thus, we have identified PDE12 inhibitors (CO-17 and CO-63), and established the principle that inhibitors of PDE12 have antiviral properties. Early studies suggest these PDE12 inhibitors are well tolerated at the therapeutic range, and reduce viral load in studies of DENV, HCV, WNV and SARS-CoV-2 in human cells and WNV in a mouse model.

Original languageEnglish (US)
Article number001865
JournalJournal of General Virology
Issue number7
StatePublished - 2023


  • 2,́5'-oligoadenylate synthetase (OAS)
  • West Nile virus (WNV)
  • dengue virus (DENV)
  • hepatitis C virus (HCV)
  • ribonuclease L (RNAseL)
  • severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

ASJC Scopus subject areas

  • Virology


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