Identification and evaluation of potential SARS-CoV-2 antiviral agents targeting mRNA cap guanine N7-Methyltransferase

Antiviral Res. 2021 Sep:193:105142. doi: 10.1016/j.antiviral.2021.105142. Epub 2021 Jul 23.

Abstract

SARS-CoV-2, the cause of the currently ongoing COVID-19 pandemic, encodes its own mRNA capping machinery. Insights into this capping system may provide new ideas for therapeutic interventions and drug discovery. In this work, we employ a previously developed Py-FLINT screening approach to study the inhibitory effects of compounds against the cap guanine N7-methyltransferase enzyme, which is involved in SARS-CoV-2 mRNA capping. We screened five commercially available libraries (7039 compounds in total) to identify 83 inhibitors with IC50 < 50 μM, which were further validated using RP HPLC and dot blot assays. Novel fluorescence anisotropy binding assays were developed to examine the targeted binding site. The inhibitor structures were analyzed for structure-activity relationships in order to define common structural patterns. Finally, the most potent inhibitors were tested for antiviral activity on SARS-CoV-2 in a cell based assay.

Keywords: COVID-19; Fluorescence assay; Inhibitor screening; nsp14.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antiviral Agents / chemistry
  • Antiviral Agents / pharmacology*
  • COVID-19 / virology
  • COVID-19 Drug Treatment*
  • Cell Line
  • Exoribonucleases / antagonists & inhibitors
  • Exoribonucleases / metabolism
  • High-Throughput Screening Assays
  • Humans
  • Inhibitory Concentration 50
  • Methyltransferases / antagonists & inhibitors*
  • Methyltransferases / metabolism
  • Nucleotidyltransferases / antagonists & inhibitors*
  • Nucleotidyltransferases / metabolism
  • RNA Caps
  • RNA, Viral / genetics
  • RNA, Viral / metabolism
  • SARS-CoV-2 / drug effects*
  • SARS-CoV-2 / genetics
  • SARS-CoV-2 / metabolism
  • Viral Nonstructural Proteins / antagonists & inhibitors
  • Viral Nonstructural Proteins / metabolism
  • Virus Replication / drug effects

Substances

  • Antiviral Agents
  • RNA Caps
  • RNA, Viral
  • Viral Nonstructural Proteins
  • Methyltransferases
  • mRNA (guanine(N7))-methyltransferase
  • Nucleotidyltransferases
  • mRNA guanylyltransferase
  • Exoribonucleases
  • NSP14 protein, SARS-CoV-2