Abstract
The COVID-19 pandemic has presented itself as one of the most critical public health challenges of the century, with SARS-CoV-2 being the third member of the Coronaviridae family to cause a fatal disease in humans. There is currently only one antiviral compound, remdesivir, that can be used for the treatment of COVID-19. To identify additional potential therapeutics, we investigated the enzymatic proteins encoded in the SARS-CoV-2 genome. In this study, we focussed on the viral RNA cap methyltransferases, which play key roles in enabling viral protein translation and facilitating viral escape from the immune system. We expressed and purified both the guanine-N7 methyltransferase nsp14, and the nsp16 2'-O-methyltransferase with its activating cofactor, nsp10. We performed an in vitro high-throughput screen for inhibitors of nsp14 using a custom compound library of over 5000 pharmaceutical compounds that have previously been characterised in either clinical or basic research. We identified four compounds as potential inhibitors of nsp14, all of which also showed antiviral capacity in a cell-based model of SARS-CoV-2 infection. Three of the four compounds also exhibited synergistic effects on viral replication with remdesivir.
Keywords:
coronavirus; covid-19; mRNA cap; methyltransferase.
© 2021 The Author(s).
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Monophosphate / analogs & derivatives
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Adenosine Monophosphate / pharmacology
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Alanine / analogs & derivatives
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Alanine / pharmacology
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Animals
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Antiviral Agents / chemistry
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Antiviral Agents / pharmacology*
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Chlorobenzenes / pharmacology
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Chlorocebus aethiops
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Drug Evaluation, Preclinical*
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Enzyme Assays
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Exoribonucleases / antagonists & inhibitors*
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Exoribonucleases / genetics
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Exoribonucleases / isolation & purification
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Exoribonucleases / metabolism
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Fluorescence Resonance Energy Transfer
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High-Throughput Screening Assays
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Indazoles / pharmacology
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Indenes / pharmacology
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Indoles / pharmacology
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Methyltransferases / antagonists & inhibitors*
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Methyltransferases / genetics
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Methyltransferases / isolation & purification
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Methyltransferases / metabolism
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Nitriles / pharmacology
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Phenothiazines / pharmacology
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Purines / pharmacology
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RNA Caps / metabolism*
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Reproducibility of Results
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SARS-CoV-2 / drug effects
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SARS-CoV-2 / enzymology*
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Small Molecule Libraries / chemistry
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Small Molecule Libraries / pharmacology*
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Substrate Specificity
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Trifluperidol / pharmacology
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Vero Cells
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Viral Nonstructural Proteins / antagonists & inhibitors*
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Viral Nonstructural Proteins / genetics
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Viral Nonstructural Proteins / isolation & purification
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Viral Nonstructural Proteins / metabolism
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Viral Regulatory and Accessory Proteins / genetics
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Viral Regulatory and Accessory Proteins / isolation & purification
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Viral Regulatory and Accessory Proteins / metabolism
Substances
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Antiviral Agents
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Chlorobenzenes
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Indazoles
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Indenes
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Indoles
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NSP10 protein, SARS-CoV-2
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NSP16 protein, SARS-CoV-2
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Nitriles
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Phenothiazines
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Purines
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RNA Caps
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Small Molecule Libraries
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Viral Nonstructural Proteins
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Viral Regulatory and Accessory Proteins
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inauzhin
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(3S,3aR)-2-(3-chloro-4-cyanophenyl)-3-cyclopentyl-3,3a,4,5-tetrahydro-2H-benzo(g)indazole-7-carboxylic acid
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remdesivir
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Adenosine Monophosphate
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Methyltransferases
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Exoribonucleases
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NSP14 protein, SARS-CoV-2
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Alanine
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Trifluperidol
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lomeguatrib