GP1a reduces PGE2-induced MMP-9 through inhibition of cAMP induction. (A) DCs were treated with cytokine cocktail without PGE2 (CC) or cytokine cocktail + PGE2 (CCP). Culture supernatants collected at different time points were analyzed for MMP-9 by ELISA. (B) DCs were treated with PGE2 (0.1μM) with or without GP1a (5μM). Supernatant collected at different time points were analyzed for MMP-9 by ELISA. (C) DCs (1 × 10⁵ cells) were treated as described in panel B. Cell lysates collected at different time points were analyzed for total cAMP by ELISA. (D) DCs were treated with PGE2 or dbcAMP (10μM) with or without GP1a for 24 hours. Supernatants were analyzed for MMP-9 by ELISA. Data are representative of 3 independent experiments.