title: Influenza virus replication in lung epithelial cells depends on redox-sensitive pathways activated by NOX4-derived ROS.
abstract: An overproduction of reactive oxygen species (ROS) mediated by NADPH oxidase 2 (NOX2) has been related to airway inflammation typical of influenza infection. Virus-induced oxidative stress may also control viral replication, but the mechanisms underlying ROS production, as well as their role in activating intracellular pathways and specific steps of viral life cycle under redox control have to be fully elucidated. In this study, we demonstrate that influenza A virus infection of lung epithelial cells causes a significant ROS increase that depends mainly on NOX4, which is upregulated at both mRNA and protein levels, while the expression of NOX2, the primary source of ROS in inflammatory cells, is downregulated. Inhibition of NOX4 activity through chemical inhibitors or RNA silencing blocks the ROS increase, prevents MAPK phosphorylation, and inhibits viral ribonucleoprotein (vRNP) nuclear export and viral release. Overall these data, obtained in cell lines and primary culture, describe a so far unrecognized role for NOX4-derived ROS in activating redox-regulated intracellular pathways during influenza virus infection and highlight their relevance in controlling specific steps of viral replication in epithelial cells. Pharmacological modulation of NOX4-mediated ROS production may open the way for new therapeutic approaches to fighting influenza by targeting cell and not the virus.
authors.affiliation: Department of Public Health and Infectious Diseases, Pasteur Institute-Fondazione Cenci-Bolognetti, Sapienza University of Rome, Rome, 00185, Italy; CEINGE Advanced Biotechnology, Naples, 80145, Italy.
authors.forename: Donatella
authors.initials: D
authors.lastname: Amatore
authors.forename: Rossella
authors.initials: R
authors.lastname: Sgarbanti
authors.forename: Katia
authors.initials: K
authors.lastname: Aquilano
authors.forename: Sara
authors.initials: S
authors.lastname: Baldelli
authors.forename: Dolores
authors.initials: D
authors.lastname: Limongi
authors.forename: Livia
authors.initials: L
authors.lastname: Civitelli
authors.forename: Lucia
authors.initials: L
authors.lastname: Nencioni
authors.forename: Enrico
authors.initials: E
authors.lastname: Garaci
authors.forename: Maria Rosa
authors.initials: MR
authors.lastname: Ciriolo
authors.forename: Anna Teresa
authors.initials: AT
authors.lastname: Palamara
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000201:enzymology / Q000821:virology*; D015870:Gene Expression; D054884:Host-Pathogen Interactions; D006801:Humans; D009980:Influenza A virus / Q000502:physiology*; D051379:Mice; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000378:metabolism*; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015854:Up-Regulation; D014779:Virus Replication
chemical_list: D017382:Reactive Oxygen Species; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human