Kinetics of 5-lipoxygenase activation, arachidonic acid release, and leukotriene synthesis in human neutrophils: effects of granulocyte-macrophage colony-stimulating factor.
The kinetics of 5-lipoxygenase (5-LO) activation in human neutrophils was compared with that of arachidonic acid (AA) release and leukotriene (LT) B4 synthesis, and the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on these processes was examined. The soluble agonists N-formyl-Met-Leu-Phe and platelet-activating factor stimulated 5-LO activity, which peaked within 10 s and then rapidly declined. At all time points investigated, 5-LO activity was greater in GM-CSF-treated neutrophils. The release of AA was detectable only in GM-CSF-treated neutrophils and peaked 1 min after the agonist stimulation. Accordingly, synthesis of LTB4 was detected only in GM-CSF-treated neutrophils. By comparison, 100 nM of ionomycin induced a greater and sustained activation of 5-LO, resulting in a greater synthesis of LTB4. These results show that 5-LO activation is immediate and transient in response to soluble agonists and that temporal dissociation with the release of AA limits LTB4 synthesis.
Centre de Recherche en Inflammation, Immunologie et Rhumatologie, Centre de Recherche du CHUL, Québec, Canada.
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Krump
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Borgeat
D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism*; D016718:Arachidonic Acid / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D015759:Ionomycin / Q000494:pharmacology; D007700:Kinetics; D015289:Leukotrienes / Q000096:biosynthesis*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D010972:Platelet Activating Factor / Q000494:pharmacology; D013997:Time Factors
D015289:Leukotrienes; D010972:Platelet Activating Factor; D016718:Arachidonic Acid; D015759:Ionomycin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D001094:Arachidonate 5-Lipoxygenase