Reversible disruption of XPO1-mediated nuclear export inhibits respiratory syncytial virus (RSV) replication

Cynthia Mathew,Reena Ghildyal,Sharon Tamir,Ralph A Tripp

doi:10.1038/s41598-021-98767-2

Abstract

Respiratory syncytial virus (RSV) is the primary cause of serious lower respiratory tract disease in infants, young children, the elderly and immunocompromised individuals. Therapy for RSV infections is limited to high risk infants and there are no safe and efficacious vaccines. Matrix (M) protein is a major RSV structural protein with a key role in virus assembly. Interestingly, M is localised to the nucleus early in infection and its export into the cytoplasm by the nuclear exporter, exportin-1 (XPO1) is essential for RSV assembly. We have shown previously that chemical inhibition of XPO1 function results in reduced RSV replication. In this study, we have investigated the anti-RSV efficacy of Selective Inhibitor of Nuclear Export (SINE) compounds, KPT-335 and KPT-185. Our data shows that therapeutic administration of the SINE compounds results in reduced RSV titre in human respiratory epithelial cell culture. Within 24 h of treatment, RSV replication and XPO1 expression was reduced, M protein was partially retained in the nucleus, and cell cycle progression was delayed. Notably, the effect of SINE compounds was reversible within 24 h after their removal. Our data show that reversible inhibition of XPO1 can disrupt RSV replication by affecting downstream pathways regulated by the nuclear exporter.

Highlights

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infections affecting a broad demographic, including neonates, children under the age of five, immunocompromised individuals and the e lderly[1,2,3]
We have previously shown that RSV M protein is localised to the nucleus early in infection, being exported to the cytoplasm later to play its central role in RSV assembly; disruption of nuclear export of M protein inhibits RSV assembly and reduces viral titre[11,12,13]
In this study we show that Selective Inhibitor of Nuclear Export (SINE) compounds reduce RSV replication when administered therapeutically and discuss the possible mechanisms

Summary

Introduction

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infections affecting a broad demographic, including neonates, children under the age of five, immunocompromised individuals and the e lderly[1,2,3]. Viruses subvert a limited set of host factors during infection to facilitate various stages of their lifecycle[8] and disruption of the function of the host factor indirectly reduces or inhibits viral r eplication[9,10]. We have previously shown that RSV M protein is localised to the nucleus early in infection, being exported to the cytoplasm later to play its central role in RSV assembly; disruption of nuclear export of M protein inhibits RSV assembly and reduces viral titre[11,12,13]. In this study we show that SINE compounds reduce RSV replication when administered therapeutically and discuss the possible mechanisms. The current study extends our previous work which showed that treatment with KPT-335 up to 72 h prior to infection inhibits RSV replication, highlighting its potential as a prophylactic agent against R SV12

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