Expression and activity of prostaglandin endoperoxide synthase‐2 in agonist‐activated human neutrophils

M Pouliot, C Gilbert, P Borgeat, PE Poubelle… - The FASEB …, 1998 - Wiley Online Library
M Pouliot, C Gilbert, P Borgeat, PE Poubelle, S Bourgoin, C Créminon, J Maclouf, SR McColl…
The FASEB journal, 1998Wiley Online Library
Proinflammatory 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‐α, 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 …
Abstract
Proinflammatory 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‐α, 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.—Pouliot, M., Gilbert, C., Borgeat, P., Poubelle, P. E., Bourgoin, S., Créminon, C., Maclouf, J., McColl, S. R., Naccache, P. H. Expression and activity of prostaglandin endoperoxide synthase‐2 in agonist‐activated human neutrophils. FASEB J. 612, 1109–1123 (1998)
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