Phorbol myristate acetate-induced NADPH oxidase activity in human neutrophils: only half the story has been told.
The paradigm for activation of the neutrophil NADPH oxidase with the protein kinase C activator phorbol myristate acetate (PMA) states that the oxidase assembles the plasma membrane and that the metabolites generated are released extracellularly. This paradigm is challenged by the results presented. Most of the PMA-induced oxidase activity measured as chemiluminescence and dichlorofluorescein fluorescence was insensitive to scavengers of superoxide anion and hydrogen peroxide. This indicates that oxidase activity also takes place in a cellular compartment that the scavengers cannot reach. From the results obtained with granule-deficient HL-60 cells and cord blood neutrophils, we suggest that the scavenger-insensitive part of the NADPH oxidase activity in normal neutrophils resides in an intracellular compartment identical to or originating from granules. Our results also indicate that specific and azurophil granules have to be in very close contact to allow the generated oxygen metabolites to reach and react with myeloperoxidase.
Lundqvist
H
H
Department of Medical Microbiology and Immunology, University of Göteborg, Sweden.
Follin
P
P
Khalfan
L
L
Dahlgren
C
C
D000328:Adult; D002454:Cell Differentiation / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D005312:Fetal Blood / Q000166:cytology / Q000201:enzymology; D005452:Fluoresceins / Q000032:analysis / Q000378:metabolism; D006105:Granulomatous Disease, Chronic / Q000097:blood; D018922:HL-60 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D008163:Luminescent Measurements; D009247:NADH, NADPH Oxidoreductases / Q000096:biosynthesis* / Q000378:metabolism; D019255:NADPH Oxidases; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology*; D010101:Oxygen Consumption; D009195:Peroxidase / Q000378:metabolism; D016897:Respiratory Burst / Q000187:drug effects; D013347:Subcellular Fractions / Q000201:enzymology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D005452:Fluoresceins; C029569:diacetyldichlorofluorescein; D006861:Hydrogen Peroxide; D009195:Peroxidase; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D013755:Tetradecanoylphorbol Acetate