Cyclooxygenase-2-dependent generation of 8-epiprostaglandin F2alfa by lipopolysaccharide-activated J774 macrophages.

Objective: The generation of 8-epiprostaglandin F2a (8-epi-PGF2a ) by arachidonic acid (AA)- and lipopolysaccharide (LPS)- stimulated J774 macrophages has been investigated. Material: Murine monocyte/macrophage J774 cell line. Methods: Cells were incubated with AA or LPS and the amount of 8-epi-PGF2a , 6-ketoprostaglandin F1a (6-keto-PGF1a ) and prostaglandin E2 (PGE2) released in the incubation mediameasured by radioimmunoassay (RIA) or, in some experiments, by enzyme immunoassay (EIA). The effect of dexamethasone (DXM), cycloheximide (CXM) and 5,5 dimethyl-3-(3-fluorophenyl)- 4-(4-methylsulfonyl)phenyl-2(5H)-furanone (DFU), a cyclooxygenase-2 (COX-2) selective inhibitor, on LPS-induced generation of AA metabolites was assessed. Results: AA induced a significant production of 6-keto- PGF1a and PGE2 , whereas LPS caused a concentration- and time-dependent increase of 8-epi-PGF2a , 6-keto-PGF1a and PGE2. DXM (2 mM) as well as CXM (1 mM) significantly decreased (p < 0.001; n = 4) the LPS-stimulated production of 8-epi-PGF2a (by 86% and 82%, respectively), 6-keto- PGF1a (by 78% and 74%, respectively) and PGE2 (by 83% and 78%, respectively). Immunostimulated production of AA metabolites was also inhibited by DFU (IC50 0.3 ± 0.04 mM; 0.16 ± 0.02 mM and 0.11 ± 0.05 mM for 8-epi-PGF2a , 6-keto-PGF1a and PGE2, respectively. Conclusions: These results demonstrate the role of COX-2 in the generation of 8-epi-PGF2a by LPS-stimulated J774 macrophages. The relevance of these findings requires further elucidation.