Figure 4

COE inhibits the transcriptional activity of MMP-9 by suppression of NF-κB activity. (A) RA-FLSs were transfected with pGL2-MMP-9WT and Renilla luciferase reporter vector plasmids. The transfected cells were pretreated with the indicated concentrations of COE for 1 h, followed by IL-1β (10 ng/ml) and TNF-α (10 ng/ml) stimulation for 48 h. The relative luciferase activity in the cell extract was normalized by Renilla luciferase activity. Each value represents the mean ± SD of triplicate experiments and is expressed relative to the control. FLSs were transfected with pGL2-MMP-9 mNF-κB (B), pGL2-MMP-9 mAP-1-U (C) and pGL2-MMP-9 mAP-1-P (D). The relative luciferase activity is normalized to Renilla luciferase activity and is expressed relative to the controls. ^* P < 0.05, ^** P < 0.01 versus normal control group, ^◆ P < 0.05, ^◆◆ P < 0.01 versus IL-1β and TNF-α combination-treated group.