The NSP14/NSP10 RNA repair complex as a Pan-coronavirus therapeutic target

Gergely Rona,Hailey V Goldberg,Andras Zeke,Bearach Miwatani-Minter,Didier Desmaële,Michele Pagano,Philippe Cotelle,Fabrice Bailly,Meike Dittmann,Sheena Faye Garcia,Thomas R Hinds,Ramanjit Kaur,Maren De Vries,Hui Wang,Austin Schinlever,Nathaniel R Landau,Ning Zheng

doi:10.1038/s41418-021-00900-1

Abstract

The risk of zoonotic coronavirus spillover into the human population, as highlighted by the SARS-CoV-2 pandemic, demands the development of pan-coronavirus antivirals. The efficacy of existing antiviral ribonucleoside/ribonucleotide analogs, such as remdesivir, is decreased by the viral proofreading exonuclease NSP14-NSP10 complex. Here, using a novel assay and in silico modeling and screening, we identified NSP14-NSP10 inhibitors that increase remdesivir’s potency. A model compound, sofalcone, both inhibits the exonuclease activity of SARS-CoV-2, SARS-CoV, and MERS-CoV in vitro, and synergistically enhances the antiviral effect of remdesivir, suppressing the replication of SARS-CoV-2 and the related human coronavirus OC43. The validation of top hits from our primary screenings using cellular systems provides proof-of-concept for the NSP14 complex as a therapeutic target.

Highlights

Coronaviruses (CoVs) are positive strand RNA viruses with a replication property unique for RNA viruses - proofreading, executed by a viral exonuclease (ExoN)
By combining a novel assay measuring the catalytic activity of NSP14/10 with in silico modeling and screening, we identified a series of inhibitors of the coronavirus NSP14/NSP10 enzyme complex showing activity both in vitro and in vivo (Supplementary Fig. 9C)
CoVs rely on their ExoN activity for proper propagation [4, 5], which is evident when measured over many replication cycles

Summary

Introduction

Coronaviruses (CoVs) are positive strand RNA viruses with a replication property unique for RNA viruses - proofreading, executed by a viral exonuclease (ExoN). The sequence and structure of NSP14 ExoN domain is highly divergent from most cellular exonuclease enzymes, including its closest mammalian relative TREX1, a DNA exonuclease. This disparity makes NSP14/10 an ideal anti-viral drug target. Based on genetic studies ExoN inhibition is expected to increase CoV sensitivity to chain terminating and mutagenic nucleotides [6, 9,10,11]. We tested the antiviral potency of our best hits using viral replication assays with HCoV-OC43 and SARS-CoV-2. There results of these studies is presented

Methods

Results

Conclusion