Activation of Leukotriene Synthesis in Human Neutrophils by Exogenous Arachidonic Acid: Inhibition by Adenosine A2aReceptor Agonists and Crucial Role of Autocrine Activation by Leukotriene B4

1999 ◽  
Vol 56 (5) ◽  
pp. 1055-1062 ◽  
Author(s):  
Marc E. Surette ◽  
Eric Krump ◽  
Serge Picard ◽  
Pierre Borgeat
Keyword(s):  
Arachidonic Acid ◽  
Crucial Role ◽  
Leukotriene B4 ◽  
Acid Inhibition ◽  
Human Neutrophils ◽  
Exogenous Arachidonic Acid

scholarly journals Na+/H+ exchange modulates the production of leukotriene B4 by human neutrophils

1989 ◽  
Vol 257 (3) ◽  
pp. 751-758 ◽  
Author(s):  
M Osaki ◽  
H Sumimoto ◽  
K Takeshige ◽  
E J Cragoe ◽  
Y Hori ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Leukotriene B4 ◽  
Human Neutrophils ◽  
Ionophore A23187 ◽  
Cytoplasmic Ph ◽  
Chemotactic Peptide ◽  
Trans Isomers ◽  
Lipoxygenase Pathway ◽  
Exogenous Arachidonic Acid ◽  
Specific Inhibitors

Human neutrophils produce various compounds of the 5-lipoxygenase pathway, including (5S)-hydroxyeicosatetraenoic acid, leukotriene B4, its 6-trans isomers and omega-oxidation metabolites of LTB4, when the cells are stimulated with the Ca2+ ionophore A23187. The elevation in the extracellular pH (pHo) facilitated the cytoplasmic alkalinization induced by the ionophore as determined fluorometrically using 2',7'-bis(carboxyethyl)carboxyfluorescein and enhanced the production of all the 5-lipoxygenase metabolites. The production decreased when the alkalinization was blocked by the decrease in the pHo, the removal of the extracellular Na+ or the addition of specific inhibitors of the Na+/H+ exchange, such as 5-(NN-hexamethylene)amiloride, 5-(N-methyl-N-isobutyl)amiloride and 5-(N-ethyl-N-isopropyl)amiloride. The alkalinization of the cytoplasm with methylamine completely restored the production suppressed by the removal of Na+ from the medium. These findings suggest that the change in the cytoplasmic pH (pHi) mediated by the Na+/H+ exchange regulates the production of the lipoxygenase metabolites. The site of the metabolism controlled by the pHi change seemed to be the 5-lipoxygenase, because the production of all the metabolites decreased in parallel and the release of [3H]arachidonic acid from the neutrophils in response to the ionophore was not affected by the pHi change. Furthermore, the production of the 5-lipoxygenase metabolites stimulated by A23187 with or without exogenous arachidonic acid showed a similar pHo-dependence and the production induced by N-formylmethionyl-leucylphenylalanine (chemotactic peptide) with exogenous arachidonic acid also decreased when the cytoplasmic alkalinization was inhibited.

scholarly journals Lipopolysaccharides prime whole human blood and isolated neutrophils for the increased synthesis of 5-lipoxygenase products by enhancing arachidonic acid availability: involvement of the CD14 antigen.

1993 ◽  
Vol 178 (4) ◽  
pp. 1347-1355 ◽  
Author(s):  
M E Surette ◽  
R Palmantier ◽  
J Gosselin ◽  
P Borgeat
Keyword(s):  
Arachidonic Acid ◽  
Mononuclear Cells ◽  
Leukotriene B4 ◽  
Eicosatetraenoic Acid ◽  
Tnf Alpha ◽  
Peripheral Blood Mononuclear ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Priming Activity

Stimulation of heparinized blood with 1 microM formyl-methionyl-leucyl-phenylalanine (FMLP) resulted in the formation of < 30 pmol/ml plasma of 5-lipoxygenase (5-LO) products. The preincubation of blood with 1 microgram/ml of lipopolysaccharide (LPS) (Escherichia coli 0111-B4) for 30 min before stimulation with FMLP resulted in the accumulation of 250-300 pmol of 5-LO products per ml plasma. The major products detected were leukotriene B4 and (5S)-hydroxy-6,8,11,14-eicosatetraenoic acid which were produced in equivalent amounts. The priming activity was detectable with as little as 1-10 ng LPS per ml blood and was optimal using 1-10 micrograms LPS/ml blood. The priming for 5-LO product synthesis was optimal after 20-30 min of preincubation with LPS and declined at preincubation times > 30 min. The priming effect of LPS was also observed using the complement fragment C5a or interleukin 8 as agonists. Polymorphonuclear leukocytes (PMN) and peripheral blood mononuclear cells accounted for 80 and 20% of the synthesis of 5-LO products, respectively. The ability of LPS to prime isolated PMN was dependent on the presence of plasma and was inhibited by the anti-CD14 antibody IOM2, indicating a CD14-dependent priming mechanism. The priming of whole blood with tumor necrosis factor alpha (TNF-alpha) and LPS was additive and the presence of mononuclear cells did not enhance the ability of LPS to prime PMN, indicating that the priming activity of LPS is independent of LPS-induced TNF-alpha synthesis. The mechanism by which LPS enhance 5-LO product synthesis in PMN was investigated. Treatment of PMN with LPS strongly enhanced the release of arachidonic acid after stimulation with FMLP. The release of arachidonic acid was optimal 2-3 min after stimulation with FMLP, attaining levels 5-15-fold greater than those observed in unprimed cells stimulated with FMLP. These results demonstrate that LPS dramatically increases the ability of blood to generate 5-LO products, and support the putative role of leukotrienes in pathological states involving LPS.

Role of sodium in intracellular calcium elevation and leukotriene B4 formation by receptor-mediated activation of human neutrophils

2004 ◽  
Vol 67 (2) ◽  
pp. 385-393 ◽  
Author(s):  
Alberto Tedeschi ◽  
Paola Ciceri ◽  
Simona Zarini ◽  
Maurizio Lorini ◽  
Manuela Di Donato ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Leukotriene B4 ◽  
Human Neutrophils ◽  
Calcium Elevation

scholarly journals Arachidonic acid activates phospholipase D in human neutrophils; essential role of endogenous leukotriene B4and inhibition by adenosine A2Areceptor engagement

2003 ◽  
Vol 73 (4) ◽  
pp. 530-539 ◽  
Author(s):  
Sonya Grenier ◽  
Nicolas Flamand ◽  
Julie Pelletier ◽  
Paul H. Naccache ◽  
Pierre Borgeat ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Phospholipase D ◽  
Essential Role ◽  
Human Neutrophils

scholarly journals The suppression of 5-lipoxygenation of arachidonic acid in human polymorphonuclear leucocytes by the 15-lipoxygenase product (15S)-hydroxy-(5Z,8Z,11Z,13E)-eicosatetraenoic acid: structure-activity relationship and mechanism of action

1996 ◽  
Vol 314 (3) ◽  
pp. 911-916 ◽  
Author(s):  
Karen PETRICH ◽  
Peter LUDWIG ◽  
Hartmut KÜHN ◽  
Tankred SCHEWE
Keyword(s):  
Fatty Acids ◽  
Arachidonic Acid ◽  
Leukotriene B4 ◽  
Eicosatetraenoic Acid ◽  
Ionophore A23187 ◽  
Polymorphonuclear Leucocytes ◽  
Lipoxygenase Inhibitor ◽  
Acid Structure ◽  
Selection Of

(15S)-Hydroxy-(5Z,8Z,11Z,13E)-eicosatetraenoic acid (15-HETE) suppresses in ionophore-A23187-stimulated human polymorphonuclear leucocytes (PMN) the conversion of exogenous arachidonic acid into leukotriene B4 (LTB4) and (5S)-hydroxy-(6E,8Z,11Z,14Z)-eicosatetraenoic acid (5-HETE). However, contrary to earlier suggestions, 15-HETE is not a genuine 5-lipoxygenase inhibitor under these conditions, but rather suppresses the 5-lipoxygenation of arachidonic acid by switching-over of substrate utilization, as judged from a sizeable formation of labelled (5S,15S)-dihydroxy-(6E,8Z,11Z,13E)-eicosatetraenoic acid (5,15-diHETE) from 15-[1-14C]HETE. Identical results were obtained with human recombinant 5-lipoxygenase. In PMN the formation of 5,15-diHETE is strongly stimulated by either hydroperoxypolyenoic fatty acids or arachidonic acid, suggesting a crucial role of the hydroperoxide tone of the cell. A comparison of a selection of hydroxypolyenoic fatty acids with respect to their capability of suppressing 5-lipoxygenation of arachidonic acid revealed that 15-monohydroxyeicosanoids throughout exhibit the highest inhibitory potencies, whereas the other HETEs, 5,15-diHETE as well as octadecanoids, are modest or poor inhibitors. The R and S enantiomers of 15-HETE do not differ from each other, excluding a receptor-like binding of the 15-hydroxy group.

scholarly journals Neutrophil activation by anti-proteinase 3 antibodies in Wegener's granulomatosis: role of exogenous arachidonic acid and leukotriene B4 generation.

1996 ◽  
Vol 184 (4) ◽  
pp. 1567-1572 ◽  
Author(s):  
F Grimminger ◽  
K Hattar ◽  
C Papavassilis ◽  
B Temmesfeld ◽  
E Csernok ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Wegener’S Granulomatosis ◽  
Wegener's Granulomatosis ◽  
Neutrophil Activation ◽  
Tnf Alpha ◽  
Lipid Mediator ◽  
Human Neutrophils ◽  
Proteinase 3 ◽  
Lipoxygenase Pathway

Among the anti-neutrophil cytoplasmic antibodies (ANCA), those targeting proteinase 3 (PR3) have a high specificity for Wegener's granulomatosis (WG). It is known that a preceding priming of neutrophils with cytokines is a prerequisite for membrane surface expression of PR3, which is then accessible to autoantibody binding. Employing a monoclonal antibody directed against human PR3 and ANCA-positive serum from WG patients with specificity for PR3, we now investigated the role of free arachidonic acid (AA) in autoantibody-related human neutrophil activation. Priming of neutrophils with tumor necrosis factor (TNF-alpha) for 15 min or exposure to anti-PR3 antibodies or incubation with free AA (10 microM) as sole events did not provoke superoxide generation, elastase secretion or generation of 5-lipoxygenase products of AA. Similarly, the combination of TNF-alpha-priming and AA incubation was ineffective. When TNF-alpha-primed neutrophils were stimulated by anti-PR3 antibodies, superoxide and elastase secretion was provoked in the absence of lipid mediator generation. However, when free AA was additionally provided, a strong activation of the 5-lipoxygenase pathway was demasked, with the appearance of excessive quantities of leukotriene (LT)B4, LTA4, and 5-hydroxyeicosatetraenoic acid. Moreover, superoxide and elastase secretion were markedly amplified, and studies with 5-lipoxygenase inhibitors and a LTB4-antagonist demonstrated this was due to an LTB4-related autocrine loop of cell activation. In contrast, the increased synthesis of platelet-activating factor in response to TNF-alpha-priming and anti-PR3 stimulation did not contribute to the amplification loop of neutrophil activation under the given conditions. We conclude that anti-PR3 antibodies are potent inductors of the 5-lipoxygenase pathway in primed human neutrophils, and extracellular free AA, as provided at an inflammatory focus, synergizes with the autoantibodies to evoke full-blown lipid mediator generation, granule secretion and respiratory burst. Such events may be enrolled in the pathogenesis of focal necrotizing vascular injury in Wegener's granulomatosis.

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