title: Granule exocytosis contributes to priming and activation of the human neutrophil respiratory burst.
abstract: The role of exocytosis in the human neutrophil respiratory burst was determined using a fusion protein (TAT-SNAP-23) containing the HIV transactivator of transcription (TAT) cell-penetrating sequence and the N-terminal SNARE domain of synaptosome-associated protein-23 (SNAP-23). This agent inhibited stimulated exocytosis of secretory vesicles and gelatinase and specific granules but not azurophil granules. GST pulldown showed that TAT-SNAP-23 bound to the combination of vesicle-associated membrane protein-2 and syntaxin-4 but not to either individually. TAT-SNAP-23 reduced phagocytosis-stimulated hydrogen peroxide production by 60% without affecting phagocytosis or generation of HOCl within phagosomes. TAT-SNAP-23 had no effect on fMLF-stimulated superoxide release but significantly inhibited priming of this response by TNF-α and platelet-activating factor. Pretreatment with TAT-SNAP-23 inhibited the increase in plasma membrane expression of gp91(phox) in TNF-α-primed neutrophils, whereas TNF-α activation of ERK1/2 and p38 MAPK was not affected. The data demonstrate that neutrophil granule exocytosis contributes to phagocytosis-induced respiratory burst activity and plays a critical role in priming of the respiratory burst by increasing expression of membrane components of the NADPH oxidase.
authors.affiliation: Department of Medicine, University of Louisville, Louisville, KY 40202, USA.
authors.forename: Silvia M
authors.initials: SM
authors.lastname: Uriarte
authors.forename: Madhavi J
authors.initials: MJ
authors.lastname: Rane
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Luerman
authors.forename: Michelle T
authors.initials: MT
authors.lastname: Barati
authors.forename: Richard A
authors.initials: RA
authors.lastname: Ward
authors.forename: William M
authors.initials: WM
authors.lastname: Nauseef
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: McLeish
mesh_terms: D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D003594:Cytoplasmic Granules / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D005089:Exocytosis / Q000235:genetics / Q000276:immunology*; D015696:Gene Products, tat / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015497:HIV-1 / Q000276:immunology; D006801:Humans; D018375:Neutrophil Activation / Q000235:genetics / Q000276:immunology*; D010587:Phagocytosis / Q000235:genetics / Q000276:immunology; D010972:Platelet Activating Factor / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000235:genetics; D050766:Qb-SNARE Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D050767:Qc-SNARE Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D016897:Respiratory Burst / Q000235:genetics / Q000276:immunology*; D050600:SNARE Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology
chemical_list: D015696:Gene Products, tat; D010972:Platelet Activating Factor; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D011993:Recombinant Fusion Proteins; C100493:SNAP23 protein, human; D050600:SNARE Proteins; D014409:Tumor Necrosis Factor-alpha