Fig. 4
Ang II increased RANKL expression in synovial cells via the ERK1/2 and JNK pathways. Synovial cells were pretreated in triplicate with or without the AT1R antagonist (olmesartan, Olm, 10−5 M) or AT2R antagonist (PD123319, PD, 10−5 M) for 30 min, and then exposed to Ang II (10−6 M) for 48 h. The relative levels of ERK1/2, JNK, and p38MAPK phosphorylation were characterized by western blot. Synovial cells were pretreated in triplicate with or without the ERK1/2 inhibitor (U0126, 5×10−6 M), the JNK inhibitor (SP600125, SP 1×10−5 M) or the p38MAPK inhibitor (SB203580, SB, 1×10−5 M) for 30 min, and then exposed to Ang II (10−6 M) for 48 h. The relative level of RANKL was determined by RT-PCR and western blot. Data are representative images or expressed as the mean ± SD of three independent experiments with synovial cells from each RA patient. a and b Western blot analysis of ERK1/2, JNK, and p38MAPK phosphorylation level (n = 3). c RT-PCR analysis of RANKL expression (n = 3). d Western blot analysis of RANKL expression (n = 3). *p < 0.05 vs. the control group; #p < 0.01 vs. the Ang II group