ATF-2/AP-1 is required for LTA-induced MMP-9 expression. a RBA-1 cells were transfected with scramble (scra) or ATF2 siRNA for 24 h, followed by stimulation with 50 μg/ml LTA for 16 h. The conditioned media and cell lysates were analyzed by gelatin zymography or Western blotting. b Cells were treated with LTA for the indicated time intervals. c Cells were pretreated with or without tanshinone IIA (TSIIA, 10 μM), Gö6976 (1 μM), NAC (10 mM), DPI (1 μM) or apocynin (10 μM) for 1 h before exposure to LTA for the indicated time intervals. The cell lysates were analyzed by Western blotting using an anti-phospho-ATF-2 (p-ATF2) or GAPDH antibody. d RBA-1 cells were pretreated with NAC (10 mM) for 1 h and then incubated with LTA (50 μg/ml) for the indicated time intervals or 90 min. The ATF-2/AP-1 binding activity was analyzed by chromatin-IP (ChIP)-PCR assay. Data are expressed as the mean of three independent experiments. #
P < 0.01, as compared with the cells stimulated with vehicle (b, d) or §
P < 0.05, as compared with the cells stimulated with LTA (d) alone. The figure represents one of three similar experiments.