Pouliot, M.Gilbert, C.Borgeat, P.Poubelle, P.Bourgoin, S.McColl, S.Naccache, P.2006-07-052006-07-051998The FASEB Journal, 1998; 12(12):1109-11230892-66381530-6860http://hdl.handle.net/2440/11554Proinflammatory agents were assessed for their capacity to stimulate the expression of the inducible cyclooxygenase isoform (COX-2) in human neutrophils. A number of agents, including PMA, opsonized bacteria and zymosan, LPS, GM-CSF, TNF-alpha, and fMLP, induced COX-2 protein expression through signaling pathways involving transcription and protein synthesis events. Northern blots showed that freshly isolated neutrophils expressed low levels of COX-2 mRNA, which rapidly increased after incubation with inflammatory agents. A characterization of the signal transduction pathways leading to COX-2 protein expression was initiated. In LPS-treated neutrophils, efficient induction of COX-2 required the presence of serum and involved ligand binding to the CD14 surface antigen. The specific inhibitor of p38 mitogen-activated protein kinase (p38 MAPK), SB 203580, had little effect on the induction of COX-2 expression in neutrophils, in contrast to what had been previously observed with other inflammatory cell types. Depending on the agonist present, ethanol differentially blocked the stimulated expression of COX-2, raising the possibility that phospholipase D activation might take part in the process of COX-2 induction. Major COX-2-derived prostanoids synthesized by inflammatory neutrophils were identified by liquid-chromatography and tandem mass-spectrometry as TXA2 and PGE2. The agonist-induced synthesis of TXA2 and PGE2 was effectively blocked by cycloheximide and by the specific COX-2 inhibitor NS-398. These results show that COX-2 can be induced in an active state by different classes of inflammatory mediators in the neutrophil. They support the concept that, in these cells, the COX-2 isoform is preeminent over COX-1 for the stimulated-production of prostanoids, and also suggest that neutrophil COX-2 displays a distinct profile of expression among circulatory cells.enNeutrophilsHumansEscherichia coliTetradecanoylphorbol AcetateIsoenzymesLipopolysaccharidesZymosanN-Formylmethionine Leucyl-PhenylalanineTumor Necrosis Factor-alphaGranulocyte-Macrophage Colony-Stimulating FactorMembrane ProteinsAntibodiesEpitopesBlotting, WesternSignal TransductionPhagocytosisTranscription, GeneticGene Expression Regulation, EnzymologicAmino Acid SequenceMolecular Sequence DataProstaglandin-Endoperoxide SynthasesCyclooxygenase 2In Vitro TechniquesJournal article0030004241001998222310.1096/fasebj.12.12.11090000757385000062-s2.0-003168978768247McColl, S. [0000-0003-0949-4660]