Fig. 3
Relative EP mRNA expression in glial cells. a EP mRNA expression in naïve astroglia and microglia cultures (n = 6–7 in three independent cultures for each cell type). For comparative purposes, the level of mRNA for each EP and cell type is expressed as fold versus mean EP1 mRNA levels in astroglia. EP4 and to a lower extent EP2 expression is comparatively higher than EP1 and EP3 in naïve microglia and is higher in microglia than astroglia (**p < 0.01, ***p < 0.001). b–g The effect of EP drug antagonist and agonist on TNF-α mRNA expression (RT-PCR) and TNF-α concentration in the culture medium (ELISA) is shown for microglia cultures 8 h after LPS in the presence or absence of exogenous PGE2 (11.3 nM) (n = 6–9 in 2–3 independent cultures). EP1 antagonist (5 μM SC 51089), EP2 antagonist (1 μM PF 04418948), EP3 antagonist (0.5 μM L-798,106), and EP4 antagonist (1 μM GW 627368) were used. b, c The EP4 antagonist abrogates the PGE2-induced reduction of TNF-α mRNA (b) and protein (c) after LPS. d, e The EP4 antagonist increases TNF-α mRNA (d) and protein (e), as assessed by ELISA in the culture medium, in cells exposed to LPS in the absence of exogenous treatment with PGE2. f, g Treatment with an EP4 agonist (100 nM ONO-4819) (f) or an EP2 agonist (1 μM butaprost) (g) reduces LPS-induced TNF-α mRNA. (n = 3–4 independent cultures, three replicates in each). *p < 0.05, **p < 0.01, ***p < 0.001 vs. LPS, &&&p < 0.001 vs. LPS + PGE2