FIGURE 4.

EP4 signaling through EPAC and PKA mediates PGE₁OH induction of IL-23p19. A, DC were stimulated with TNFα in the presence or absence of PGE₁OH or the EPAC activator 8′-CPT (100 μm, 250 μm). B–D, DC were pretreated with the PKA inhibitors H89 (B), KT5720 (KT) (C), and PKI-(5–24) (PKI) (D) for 3 h. Expression levels of IL-23p19 were determined by real-time RT-PCR. ** indicates p < 0.01 compared with TNFα + PGE₁OH (B and C), and *** indicates p < 0.001 compared with TNFα alone (A) and to TNFα + PGE₁OH (B–D). Data are representative of three independent experiments.