Targeting membrane-bound viral RNA synthesis reveals potent inhibition of diverse coronaviruses including the middle East respiratory syndrome virus

PLoS Pathog. 2014 May 29;10(5):e1004166. doi: 10.1371/journal.ppat.1004166. eCollection 2014 May.

Abstract

Coronaviruses raise serious concerns as emerging zoonotic viruses without specific antiviral drugs available. Here we screened a collection of 16671 diverse compounds for anti-human coronavirus 229E activity and identified an inhibitor, designated K22, that specifically targets membrane-bound coronaviral RNA synthesis. K22 exerts most potent antiviral activity after virus entry during an early step of the viral life cycle. Specifically, the formation of double membrane vesicles (DMVs), a hallmark of coronavirus replication, was greatly impaired upon K22 treatment accompanied by near-complete inhibition of viral RNA synthesis. K22-resistant viruses contained substitutions in non-structural protein 6 (nsp6), a membrane-spanning integral component of the viral replication complex implicated in DMV formation, corroborating that K22 targets membrane bound viral RNA synthesis. Besides K22 resistance, the nsp6 mutants induced a reduced number of DMVs, displayed decreased specific infectivity, while RNA synthesis was not affected. Importantly, K22 inhibits a broad range of coronaviruses, including Middle East respiratory syndrome coronavirus (MERS-CoV), and efficient inhibition was achieved in primary human epithelia cultures representing the entry port of human coronavirus infection. Collectively, this study proposes an evolutionary conserved step in the life cycle of positive-stranded RNA viruses, the recruitment of cellular membranes for viral replication, as vulnerable and, most importantly, druggable target for antiviral intervention. We expect this mode of action to serve as a paradigm for the development of potent antiviral drugs to combat many animal and human virus infections.

MeSH terms

  • Animals
  • Antiviral Agents / pharmacology*
  • Cell Line
  • Cell Membrane / metabolism
  • Coronavirus Infections / prevention & control
  • Coronavirus Infections / virology*
  • Coronavirus*
  • Humans
  • RNA, Viral / genetics*
  • Respiratory Syncytial Viruses*
  • Virus Internalization / drug effects
  • Virus Replication / drug effects*

Substances

  • Antiviral Agents
  • RNA, Viral

Grant support

This work was supported by the Swiss National Science Foundation (VT, RD, EK), the 3R Research Foundation, Switzerland (VT, RD, HRJ), the German Research Foundation (Priority Programme 1596, VT), Swedish grants 71650 and 71690 from the Sahlgrenska University Hospital Läkarutbildningsavtal/ALF, and grant from Mizutani Foundation. AL was supported by grant MN58/07 from the Torsten and Ragnar Söderberg Foundation. CD was supported by the European Union FP7 projects EMPERIE (contract number 223498) and ANTIGONE (contract number 278976), the German Research Foundation (DFG grant DR 772/3-1), as well as the German Ministry of Education and Research (BMBF SARS II, 01KI1005A). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.