Figure 5

TNF-α induces MMP-9 expression via JNK1/2 phosphorylation. (A) Cells were pretreated with SP600125 for 1 h and then incubated with TNF-α (15 ng/ml) for 24 h. (B) Cells were pretreated with SP600125 (3 μM) for 1 h and then incubated with TNF-α (15 ng/ml) for 6 h. The isolated RNA samples were analyzed for the levels of MMP-9 mRNA by real-time PCR. (C) Cells were pretreated without or with SP600125 for 1 h and then incubated with TNF-α (15 ng/ml) for various time intervals. The cell lysates were analyzed by Western blot using an anti-phospho-JNK1/2 antibody or anti-GAPDH (as an internal control) antibody. Data are expressed as mean±SEM of three independent experiments. ^#P < 0.01, as compare to the cells treated with TNF-α alone. *P < 0.05, as compare to the cells treated with TNF-α alone (A) or vehicle (C). (D) Cells were transfected with JNK2 siRNA for 24 h and then incubated with TNF-α (15 ng/ml) for 24 h. (A,D) MMP-9 expression was determined as described in Figure 1. The cell lysates were determined by Western blot using an anti-JNK2 or anti-GAPDH antibody.