Montelukast counteracts the influenza virus-induced block in unfolded protein stress response and reduces virus multiplication

Influenza A viruses generate annual epidemics and occasional pandemics of respiratory disease with important consequences for human health and economy. Therefore, a large effort has been devoted to the development of new anti-influenza drugs directed to viral targets, as well as to the identification of cellular targets amenable for anti-influenza therapy. Here we describe a new approach to identify such potential cellular targets by screening collections of drugs approved for human use. We reasoned that this would most probably ensure addressing a cellular target and, if successful, the compound would have a well known pharmacological profile. In addition, we reasoned that a screening using a GFP-based recombinant replicon system would address virus trancription/replication and/or gene expression, and hence address a stage in virus infection more useful for inhibition. By using such strategy we identified Montelukast as an inhibitor of virus gene expression, which reduced virus multiplication in virus-infected cells but did not alter virus RNA synthesis in vitro or viral RNA accumulation in vivo. By deep sequencing of RNA isolated from mock- and virus-infected human cells, treated or not with Montelukast, we identified the PERK-mediated unfolded protein response as the pathway responsible for Montelukast action. Accordingly, PERK phosphorylation was inhibited in infected cells but stimulated in Montelukast-treated cells. These results suggest the PERK-mediated unfolded protein response as a potential cellular target to modulate influenza virus infection. Overall design: Comparison of gene expression measured by deep sequencing (single-ends, 50nt, RNA-seq) of "Infected", "Not infected", "Infected+Montelukast" and "Not infect+Montelukast" in human A549 cells. Infected means "Infected with influenza virus".

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Landeras-Bueno S, Fernández Y, Falcón A, Oliveros JC, Ortín J