title: The voltage-gated proton channel Hv1/VSOP inhibits neutrophil granule release.
abstract: Neutrophil granule exocytosis is crucial for host defense and inflammation. Neutrophils contain 4 types of granules, the exocytotic release of which is differentially regulated. This exocytosis is known to be driven by diverse mediators, including calcium and nucleotides, but the precise molecular mechanism remains largely unknown. We show in the present study that voltage-gated proton (Hv) channels are necessary for the proper release of azurophilic granules in neutrophils. On activation of NADPH oxidase by PMA and IgG, neutrophils derived from Hvcn1 gene knockout mouse exhibited greater secretion of MPO and elastase than WT cells. In contrast, release of LTF enriched in specific granules was not enhanced in these cells. The excess release of azurophilic granules in Hv1/VSOP-deficient neutrophils was suppressed by inhibiting NADPH oxidase activity and, in part, by valinomycin, a potassium ionophore. In addition, Hv1/VSOP-deficient mice exhibited more severe lung inflammation after intranasal Candida albicans infection than WT mice. These findings suggest that the Hv channel acts to specifically dampen the release of azurophilic granules through, in part, the suppression of increased positive charges at the plasma membrane accompanied by the activation of NADPH oxidase in neutrophils.
authors.affiliation: *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan okochyo@phys2.med.osaka-u.ac.jp yokamura@phys2.med.osaka-u.ac.jp.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Okochi
authors.affiliation: *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Aratani
authors.affiliation: *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
authors.forename: Hibret A
authors.initials: HA
authors.lastname: Adissu
authors.affiliation: *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
authors.forename: Nana
authors.initials: N
authors.lastname: Miyawaki
authors.affiliation: *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Sasaki
authors.affiliation: *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan okochyo@phys2.med.osaka-u.ac.jp yokamura@phys2.med.osaka-u.ac.jp.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Okamura
mesh_terms: D000818:Animals; D015550:Cell Degranulation / Q000235:genetics / Q000276:immunology; D002462:Cell Membrane / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000378:metabolism*; D005089:Exocytosis; D005260:Female; D007074:Immunoglobulin G / Q000276:immunology; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism*; D008168:Lung / Q000276:immunology / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D019255:NADPH Oxidases / Q000378:metabolism; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D022142:Secretory Vesicles / Q000378:metabolism
chemical_list: C540876:Hv1 proton channel, mouse; D007074:Immunoglobulin G; D007473:Ion Channels; D009195:Peroxidase; D019255:NADPH Oxidases
keywords: inflammation; proton channel