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Author Notes:

E-mail: rplempe@emory.edu

Conceived and designed the experiments: SAK MN JPS RKP.

Performed the experiments: SAK JMN J-JY MD AS RKP.

Analyzed the data: SAK JMN JPS RKP.

Contributed reagents/materials/analysis tools: AS MN.

Wrote the paper: SAK JMN RKP.

We are grateful to D. C. Liotta and R. W. Arrendale (Emory University and Emory Institute for Drug Development) for support and LC-MS/MS analysis of compound samples, and A. L. Hammond for critical reading of the manuscript.

MuV strain South Africa, sindbis virus, and SO-influenza isolates Texas and Mexico were kind gifts of P. A. Rota (Centers for Disease Control and Prevention), W. J. Bellini (Centers for Disease Control and Prevention) and D. A. Steinhauer (Emory University), respectively.

We also thank Scynexis Inc. for assistance with experimentation involving human S9 hepatocytes.

The authors have declared that no competing interests exist.


Research Funding:

This work was supported, in part, by Public Health Service Grants AI071002 and AI085328 (to R.K.P.) from the NIH/NIAID.

The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

No additional external funding was received for this study.

Potent Host-Directed Small-Molecule Inhibitors of Myxovirus RNA-Dependent RNA-Polymerases


Journal Title:



Volume 6, Number 5


Type of Work:

Article | Final Publisher PDF


Therapeutic targeting of host cell factors required for virus replication rather than of pathogen components opens new perspectives to counteract virus infections. Anticipated advantages of this approach include a heightened barrier against the development of viral resistance and a broadened pathogen target spectrum. Myxoviruses are predominantly associated with acute disease and thus are particularly attractive for this approach since treatment time can be kept limited. To identify inhibitor candidates, we have analyzed hit compounds that emerged from a large-scale high-throughput screen for their ability to block replication of members of both the orthomyxovirus and paramyxovirus families. This has returned a compound class with broad anti-viral activity including potent inhibition of different influenza virus and paramyxovirus strains. After hit-to-lead chemistry, inhibitory concentrations are in the nanomolar range in the context of immortalized cell lines and human PBMCs. The compound shows high metabolic stability when exposed to human S-9 hepatocyte subcellular fractions. Antiviral activity is host-cell species specific and most pronounced in cells of higher mammalian origin, supporting a host-cell target. While the compound induces a temporary cell cycle arrest, host mRNA and protein biosynthesis are largely unaffected and treated cells maintain full metabolic activity. Viral replication is blocked at a post-entry step and resembles the inhibition profile of a known inhibitor of viral RNA-dependent RNA-polymerase (RdRp) activity. Direct assessment of RdRp activity in the presence of the reagent reveals strong inhibition both in the context of viral infection and in reporter-based minireplicon assays. In toto, we have identified a compound class with broad viral target range that blocks host factors required for viral RdRp activity. Viral adaptation attempts did not induce resistance after prolonged exposure, in contrast to rapid adaptation to a pathogen-directed inhibitor of RdRp activity.

Copyright information:

© Krumm et al.

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
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