Roles of phosphatidylinositol 3-kinase and phospholipase D in temporal activation of superoxide production in FMLP-stimulated human neutrophils.
To determine the temporal roles of phosphatidylinositol 3-kinase (PI3-kinase) and phospholipase D (PLD) during human neutrophil activation stimulated by a chemotactic peptide, we examined the kinetics of these enzymes and related them to a neutrophil function (superoxide production). Both wortmannin and 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002), potent and specific inhibitors of PI3-kinase, inhibit PI3-kinase activity in human neutrophils and significantly inhibit superoxide production from the early phase. Ethanol has no effect on PI3-kinase and markedly inhibits superoxide production at the late phase. Although these agents are inhibitory to different degrees, when neutrophils are simultaneously treated with ethanol and PI3-kinase inhibitors, superoxide is not produced. These results suggest that PI3-kinase and PLD play a pivotal role in the signal transduction pathway of the chemo-attractant-receptor involved neutrophil activation. These enzymes produce second messengers which are required for subsequent superoxide production in human neutrophils. NADPH oxidase is activated in a PI3-kinase-dependent manner at the early phase, and PLD activity follows it and is related to superoxide production at the late phase in human neutrophils by stimulation with FMLP.
Department of Pediatrics, Shinshu University School of Medicine, Matsumoto 390, Japan. k-yasui@hsp.nd.shinshu-u.ac.jp
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D000730:Androstadienes / Q000494:pharmacology; D002867:Chromones / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D009025:Morpholines / Q000494:pharmacology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism*; D019255:NADPH Oxidases / Q000378:metabolism; D009504:Neutrophils / Q000201:enzymology* / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism / Q000502:physiology*; D010739:Phospholipase D / Q000502:physiology*; D015398:Signal Transduction; D013481:Superoxides / Q000378:metabolism*; D013997:Time Factors; D000077191:Wortmannin
D000730:Androstadienes; D002867:Chromones; D004791:Enzyme Inhibitors; D009025:Morpholines; D013481:Superoxides; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D000431:Ethanol; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019255:NADPH Oxidases; D019869:Phosphatidylinositol 3-Kinases; D010739:Phospholipase D; D000077191:Wortmannin