Inhibition of Monkeypox virus replication by RNAi

Abstract

Orthopoxviruses cause human diseases with various severities and outcome ranging from mild conditions to death in fulminating cases. Currently, vaccination is the only protective measure against infection with these viruses and no licensed antiviral drug therapy is available. We investigated the potential of RNA interference (RNAi) in inhibiting Monkeypox virus (MPV) replication. Based on genome‐wide expression study, we selected 12 viral genes for targeting by small interference RNA (siRNA). Forty‐eight siRNA constructs were developed and evaluated in vitro for their ability to inhibit viral replication. Two genes, each targeted with four different siRNA constructs in one pool, were detrimental to viral replication. Seven siRNA constructs from these two pools, targeting either an essential gene for viral replication (A6R) or an important gene in viral entry (E8L), inhibited viral replication in cell culture by 65–95% with no apparent cytotoxicity. Further analysis using wild‐type and recombinant MPV expressing green fluorescence protein identified the most potent construct (siA6‐a) that inhibited virus replication with IC50 less than 5nM. These results identify A6R as an essential gene in MPV replication, and validate RNAi applications in developing antivirals for MPV and other Orthopoxviruses. This work was supported by a grant from the DTRA, Project number 4.10022_07_RD_B.

Monkeypox outbreak 2022: What we know so far and its potential drug targets and management strategies

“…Two genes targeted by four distinct siRNA constructs in a pool were detrimental to viral propagation. Seven siRNA constructs from these two pools, targeting either a key gene for viral entry (E8L) or an essential gene for viral replication (A6R), reduced viral replication in cell culture by 65%–95% without exhibiting any obvious harm 97 …”