title: Ataxia telangiectasia mutated kinase mediates NF-κB serine 276 phosphorylation and interferon expression via the IRF7-RIG-I amplification loop in paramyxovirus infection.
abstract: Respiratory syncytial virus (RSV) is a primary etiological agent of childhood lower respiratory tract disease. Molecular patterns induced by active infection trigger a coordinated retinoic acid-inducible gene I (RIG-I)-Toll-like receptor (TLR) signaling response to induce inflammatory cytokines and antiviral mucosal interferons. Recently, we discovered a nuclear oxidative stress-sensitive pathway mediated by the DNA damage response protein, ataxia telangiectasia mutated (ATM), in cytokine-induced NF-κB/RelA Ser 276 phosphorylation. Here we observe that ATM silencing results in enhanced single-strand RNA (ssRNA) replication of RSVand Sendai virus, due to decreased expression and secretion of type I and III interferons (IFNs), despite maintenance of IFN regulatory factor 3 (IRF3)-dependent IFN-stimulated genes (ISGs). In addition to enhanced oxidative stress, RSV replication enhances foci of phosphorylated histone 2AX variant (γH2AX), Ser 1981 phosphorylation of ATM, and IKKγ/NEMO-dependent ATM nuclear export, indicating activation of the DNA damage response. ATM-deficient cells show defective RSV-induced mitogen and stress-activated kinase 1 (MSK-1) Ser 376 phosphorylation and reduced RelA Ser 276 phosphorylation, whose formation is required for IRF7 expression. We observe that RelA inducibly binds the native IFN regulatory factor 7 (IRF7) promoter in an ATM-dependent manner, and IRF7 inducibly binds to the endogenous retinoic acid-inducible gene I (RIG-I) promoter. Ectopic IRF7 expression restores RIG-I expression and type I/III IFN expression in ATM-silenced cells. We conclude that paramyxoviruses trigger the DNA damage response, a pathway required for MSK1 activation of phospho Ser 276 RelA formation to trigger the IRF7-RIG-I amplification loop necessary for mucosal IFN production. These data provide the molecular pathogenesis for defects in the cellular innate immunity of patients with homozygous ATM mutations.
  
  
  OBJECTIVE
  RNA virus infections trigger cellular response pathways to limit spread to adjacent tissues. This "innate immune response" is mediated by germ line-encoded pattern recognition receptors that trigger activation of two, largely independent, intracellular NF-κB and IRF3 transcription factors. Downstream, expression of protective antiviral interferons is amplified by positive-feedback loops mediated by inducible interferon regulatory factors (IRFs) and retinoic acid inducible gene (RIG-I). Our results indicate that a nuclear oxidative stress- and DNA damage-sensing factor, ATM, is required to mediate a cross talk pathway between NF-κB and IRF7 through mediating phosphorylation of NF-κB. Our studies provide further information about the defects in cellular and innate immunity in patients with inherited ATM mutations.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA.
authors.forename: Ling
authors.initials: L
authors.lastname: Fang
authors.affiliation: Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Choudhary
authors.affiliation: Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA.
authors.forename: Bing
authors.initials: B
authors.lastname: Tian
authors.affiliation: Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA.
authors.forename: Istvan
authors.initials: I
authors.lastname: Boldogh
authors.affiliation: Department of Radiation Oncology, Houston Methodist Research Institute, Weill Cornell University, Houston, Texas, USA.
authors.forename: Chunying
authors.initials: C
authors.lastname: Yang
authors.affiliation: Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA.
authors.forename: Teodora
authors.initials: T
authors.lastname: Ivanciuc
authors.affiliation: Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA.
authors.forename: Yinghong
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA.
authors.forename: Roberto P
authors.initials: RP
authors.lastname: Garofalo
authors.affiliation: Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA Sealy Center for Molecular Medicine, University of Texas Medical Branch, Galveston, Texas, USA Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA arbrasie@utmb.edu.
authors.forename: Allan R
authors.initials: AR
authors.lastname: Brasier
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism*; D002460:Cell Line; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases / Q000378:metabolism*; D004847:Epithelial Cells / Q000276:immunology / Q000821:virology; D020868:Gene Silencing; D006801:Humans; D050839:Interferon Regulatory Factor-7 / Q000378:metabolism*; D007372:Interferons / Q000096:biosynthesis*; D016328:NF-kappa B / Q000378:metabolism*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D011971:Receptors, Immunologic; D012136:Respiratory Syncytial Viruses / Q000276:immunology* / Q000502:physiology; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000378:metabolism; D029082:Sendai virus / Q000276:immunology* / Q000502:physiology; D014779:Virus Replication
chemical_list: C494234:IRF7 protein, human; D050839:Interferon Regulatory Factor-7; D016328:NF-kappa B; D011971:Receptors, Immunologic; D007372:Interferons; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D038744:Ribosomal Protein S6 Kinases, 90-kDa; C116919:mitogen and stress-activated protein kinase 1; C452820:RIGI protein, human; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases