The transcriptional co-activator p300 contributes to LTA-induced MMP-9 expression. a Cells were pretreated with or without GR343 for 1 h before exposure to 50 μg/ml LTA for 16 h. The conditioned media were analyzed by gelatin zymography. b, c Cells were pretreated without or with Gö6976 (Gö, 1 μM), DPI (1 μM), apocynin (10 μM) or NAC (10 mM) for 1 h, and then incubated with 50 μg/ml LTA for the indicated time intervals (b) or 90 min (c). The cell lysates were analyzed by Western blotting using an anti-phospho-p300 (p-p300) or GAPDH antibody. d Cells were transfected with scramble (scra) or p300 siRNA for 24 h, followed by stimulation with 50 μg/ml LTA for 16 h. The conditioned media and cell lysates were collected and analyzed by gelatin zymography or Western blotting. Data are expressed as the mean of three independent experiments. *
P < 0.05; #
P < 0.01, as compared with the cells stimulated with vehicle (b) or LTA (a, c) alone. The figure represents one of three similar experiments.