title: Activation of the human neutrophil 5-lipoxygenase by leukotriene B4.
abstract: 1. In the present study, we demonstrate that leukotriene B4 (LTB4) has the ability to activate the human neutrophil 5-lipoxygenase (5-LO). 2. Stimulation of neutrophils with 30 nM 14,15-dideuterio-LTB4 (D2-LTB4) failed to induce the synthesis of LTB4 from endogenous arachidonic acid (AA), but stimulated the formation of LTB4 from 3.3 microM exogenous AA, as determined by GC-MS analysis. 3. The stimulatory effect of LTB4 on 5-LO activity was further examined with an alternative substrate; LTB4 time- and dose-dependently stimulated the 5-LO-mediated conversion of exogenous 15(S)-hydroperoxy-5,8,11,13-(Z,Z,Z,E)-eicosatetraenoate (15-HpETE) into 5(S),15(S)-dihydroxy-6,8,11,13,-(E,Z,Z,E)-eicosatetraenoate (5,15-DiHETE), with a threshold effect at 300 pM. 4. The ability of LTB4 to activate the 5-LO showed structural specificity, since LTB4 was found to be 100 times more potent than omega-hydroxy-LTB4, and 300 times more potent than its delta 6-trans-12-epi-isomer. 5. The LTB4-induced 5-LO activation was effectively inhibited by MK-886 (an inhibitor of 5-LO translocation), by pertussis toxin, and by the LTB4 receptor antagonist, LY-223982. 6. These results demonstrate that the binding of LTB4 to its cell-surface receptor results in 5-LO activation in a process mediated by pertussis toxin-sensitive guanine nucleotide-binding proteins. Our data also suggest that the underlying mechanism involves a translocation of the 5-LO to the membrane. These findings raise the possibility that LTB4 produced by phagocytes may positively feedback on its own synthesis.
authors.affiliation: Centre de recherche en Inflammation, l'Université Laval, Sainte-Foy, Québec, Canada.
authors.forename: P P
authors.initials: PP
authors.lastname: McDonald
authors.forename: S R
authors.initials: SR
authors.lastname: McColl
authors.forename: P H
authors.initials: PH
authors.lastname: Naccache
authors.forename: P
authors.initials: P
authors.lastname: Borgeat
mesh_terms: D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism*; D016718:Arachidonic Acid / Q000378:metabolism; D001577:Benzophenones / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism; D007211:Indoles / Q000494:pharmacology; D007975:Leukotriene B4 / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D015289:Leukotrienes / Q000378:metabolism; D008054:Lipid Peroxides / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology*; D037342:Pertussis Toxin; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D002722:Chlorobenzenes
chemical_list: D001094:Arachidonate 5-Lipoxygenase; D016718:Arachidonic Acid; D001577:Benzophenones; D006893:Hydroxyeicosatetraenoic Acids; D007211:Indoles; D007975:Leukotriene B4; D015289:Leukotrienes; D008054:Lipid Peroxides; D037342:Pertussis Toxin; D010566:Virulence Factors, Bordetella; C060893:MK-886; D002722:Chlorobenzenes; C065916:LY 223982; C025086:15-hydroperoxy-5,8,11,13-eicosatetraenoic acid; C034922:5,15-dihydroxy-6,8,11,13-eicosatetraenoic acid