Figure 6

Signaling pathways involved in Cyr61 regulating IL-8 production in RA FLS. (A) Effect of inhibitors of signaling pathways on Cyr61-induced IL-8 expression. Up: FLS were treated with 4 μM PDTC, 20 μM SP600125, 1 μM PD98059 or 10 μM SB203580 in combination with Cyr61 (5 μg/ml) (shadow bars) for 2 hours, and IL-8 mRNA relative expression was evaluated by real-time PCR. Down: RA FLS were treated with 4 μM PDTC, 20 μM SP600125, 1 μM PD98059 or 10 μM SB203580 in combination with Cyr61 (5 μg/ml) (shadow bars) for 48 hours, and IL-8 protein level was examined by ELISA. Control (open bar), Cyr61 (no inhibitors, black bar). Data represent the mean ± SEM of at least three independent experiments. * P <0.05, ** P <0.01. (B) Phosphorylation of JNK and ERK1/2 was detected by western blotting. Lane 1: unstimulated FLS, lane 2 and lane 3: stimulated with Cyr61 (5 μg/ml) for 10 minutes and 30 minutes, respectively. (C) Phosphorylation of AKT and NF-κB was detected by western blotting. Lane 1: unstimulated FLS, lane 2 and lane 3: stimulated with Cyr61 (5 μg/ml) for 10 minutes and 30 minutes, respectively.