EP4 antagonist reduces LPS-induced PGE2 and MMP-9 levels in cultures of elicited peritoneal macrophages by attenuating mPGES-1 and Cox-2 expression. Thioglycollate-elicited macrophages (12-well plate; 7.5 × 105/well) were pre-incubated 30 min with DMEM-0.01% LE-BSA (Ctrl) or media containing AH23848 or celecoxib, and then incubated 18 h with 10 ng/ml LPS. [A] Total RNA was recovered and levels of mPGES-1, Cox-2 and actin mRNA were determined utilizing PCR. [B,C] Conditioned media were recovered and levels of PGE2 and MMP-9 were determined utilizing ELISA and Western blot, respectively. Data are representative blots and the mean levels (± SD) of target mRNAs and protein, presented as RDUs, of 3 experiments. PGE2 levels are presented as the means (± SD) of 3 experiments.