title: ATP-mediated activation of the NADPH oxidase DUOX1 mediates airway epithelial responses to bacterial stimuli.
abstract: Activation of the NADPH oxidase homolog dual oxidase 1 (DUOX1) within the airway epithelium represents a key mechanism of innate airway host defense, through enhanced production of H2O2, which mediates cellular signaling pathways that regulate the production of various inflammatory mediators. Production of the CXC chemokine interleukin (IL)-8/CXCL8 forms a common epithelial response to many diverse stimuli, including bacterial and viral triggers, environmental oxidants, and other biological mediators, suggesting the potential involvement of a common signaling pathway that may involve DUOX1-dependent H2O2 production. Following previous reports showing that DUOX1 is activated by extracellular ATP and purinergic receptor stimulation, this study demonstrates that airway epithelial IL-8 production in response to several bacterial stimuli involves ATP release and DUOX1 activation. ATP-mediated DUOX1 activation resulted in the activation of ERK1/2 and NF-kappaB pathways, which was associated with epidermal growth factor receptor (EGFR) ligand shedding by ADAM17 (a disintegrin and metalloproteinase-17). Although ATP-mediated ADAM17 activation and IL-8 release were not prevented by extracellular H2O2 scavenging by catalase, these responses were attenuated by intracellular scavengers of H2O2 or related oxidants, suggesting an intracellular redox signaling mechanism. Both ADAM17 activation and IL-8 release were suppressed by inhibitors of EGFR/ERK1/2 signaling, which can regulate ADAM17 activity by serine/threonine phosphorylation. Collectively, our results indicate that ATP-mediated DUOX1 activation represents a common response mechanism to several environmental stimuli, involving H2O2-dependent EGFR/ERK activation, ADAM17 activation, and EGFR ligand shedding, leading to amplified epithelial EGFR activation and IL-8 production.
authors.affiliation: Department of Pathology, University of Vermont, Burlington, Vermont 05405, USA.
authors.forename: Agnes W
authors.initials: AW
authors.lastname: Boots
authors.forename: Milena
authors.initials: M
authors.lastname: Hristova
authors.forename: David I
authors.initials: DI
authors.lastname: Kasahara
authors.forename: Guido R M M
authors.initials: GR
authors.lastname: Haenen
authors.forename: Aalt
authors.initials: A
authors.lastname: Bast
authors.forename: Albert
authors.initials: A
authors.lastname: van der Vliet
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism; D000072198:ADAM17 Protein; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D015153:Blotting, Western; D001980:Bronchi / Q000187:drug effects / Q000201:enzymology / Q000276:immunology*; D002478:Cells, Cultured; D000074623:Dual Oxidases; D004848:Epithelium / Q000187:drug effects / Q000201:enzymology / Q000276:immunology*; D066246:ErbB Receptors / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007124:Immunoenzyme Techniques; D016209:Interleukin-8 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D020545:Respiratory Mucosa / Q000187:drug effects / Q000201:enzymology / Q000276:immunology*; D012486:Salmonella typhimurium / Q000472:pathogenicity*; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D016209:Interleukin-8; D008070:Lipopolysaccharides; D016328:NF-kappa B; D034741:RNA, Small Interfering; D016212:Transforming Growth Factor beta; D000255:Adenosine Triphosphate; D006861:Hydrogen Peroxide; D000074623:Dual Oxidases; D019255:NADPH Oxidases; C431513:DUOX1 protein, human; D066246:ErbB Receptors; D048049:Extracellular Signal-Regulated MAP Kinases; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human