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.
Yasui
K
K
Department of Pediatrics, Shinshu University School of Medicine, Matsumoto 390, Japan. k-yasui@hsp.nd.shinshu-u.ac.jp
Komiyama
A
A
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