title: Central role of double-stranded RNA-activated protein kinase in microbial induction of nitric oxide synthase.
abstract: NO synthase 2 (NOS2) is induced in airway epithelium by influenza virus infection. NOS2 induction late in the course of viral infection may occur in response to IFN-gamma, but early in infection gene expression may be induced by the viral replicative intermediate dsRNA through the dsRNA-activated protein kinase (PKR). Since PKR activates signaling pathways important in NOS2 gene induction, we determined whether PKR is a component in the signal transduction pathway leading to NOS2 gene expression after viral infection of airway epithelium. We show that NOS2 gene expression in human airway epithelial cells occurs in response to influenza A virus or synthetic dsRNA. Furthermore, dsRNA leads to rapid activation of PKR, followed by activation of signaling components including NF-kappaB and IFN regulatory factor 1. NOS2 expression is markedly diminished and IFN regulatory factor 1 and NF-kappaB activation are substantially impaired in PKR null cells. Strikingly, NOS2 induction in response to LPS is abolished in PKR null cells, confirming a central role for PKR in the general signaling pathway to NOS2.
authors.affiliation: Departments of Pulmonary and Critical Care Medicine, Cancer Biology, Immunology, and Microbiology, Cleveland Clinic Foundation, Lerner Research Institute, Cleveland, OH 44195, USA.
authors.forename: K
authors.initials: K
authors.lastname: Uetani
authors.forename: S D
authors.initials: SD
authors.lastname: Der
authors.forename: M
authors.initials: M
authors.lastname: Zamanian-Daryoush
authors.forename: C
authors.initials: C
authors.lastname: de La Motte
authors.forename: B Y
authors.initials: BY
authors.lastname: Lieberman
authors.forename: B R
authors.initials: BR
authors.lastname: Williams
authors.forename: S C
authors.initials: SC
authors.lastname: Erzurum
mesh_terms: D000818:Animals; D001980:Bronchi / Q000166:cytology / Q000201:enzymology / Q000378:metabolism / Q000821:virology; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D004789:Enzyme Activation; D004790:Enzyme Induction; D004847:Epithelial Cells / Q000201:enzymology / Q000378:metabolism / Q000821:virology; D006801:Humans; D009980:Influenza A virus / Q000502:physiology*; D050856:Interferon Regulatory Factor-1; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016328:NF-kappa B / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D010750:Phosphoproteins / Q000096:biosynthesis; D012330:RNA, Double-Stranded / Q000138:chemical synthesis / Q000502:physiology*; D012367:RNA, Viral / Q000138:chemical synthesis / Q000494:pharmacology; D019892:eIF-2 Kinase / Q000172:deficiency / Q000235:genetics / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; C494258:Irf1 protein, mouse; D016328:NF-kappa B; D010750:Phosphoproteins; D012330:RNA, Double-Stranded; D012367:RNA, Viral; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D019892:eIF-2 Kinase