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. 2001 Jul 1;108(1):73–81. doi: 10.1172/JCI12466

Figure 5.

Figure 5

Effect of MAP kinase inhibitors on AP-1 expression and collagenase gene. Cultured FLS were stimulated with medium or 2 ng/ml of IL-1 for 18 hours (Northern blot analysis) and 1 hour (electrophoretic mobility shift assay [EMSA]) in the presence of medium, SP600125, PD98059, or SB203580. In EMSA experiments (a), SP600125 (20 μM), PD98059 (100 μM), or SB203580 (3 μM) were tested (n = 3; two separate experiments are shown). Note that the JNK inhibitor SP600125 decreased AP-1 binding in nuclear extracts of IL-1–stimulated FLS. The ERK/MEK inhibitor had a modest effect, and the p38 inhibitor did not alter AP-1 binding. (b) Northern blot analysis in which increasing concentrations of the inhibitors were tested for the ability to inhibit collagenase gene expression: SP600125 (0–20 μM; JNK inhibitor), PD98059 (0–100 μM; MEK/ERK inhibitor), or SB203580 (0–3 μM; p38 inhibitor) (n = 3). SP600125 and, to a lesser extent, PD98059 decreased MMP1 gene expression. GAPDH shows equal loading of RNA in each lane. Here, 20 μM of SP600125 inhibited IL-1–induced MMP1 induction (GAPDH-normalized MMP1 gene expression for medium = 0.66; IL-1 = 1.70; IL-1 + SP600125 10 μM = 1.28; IL-1 + SP600125 20 μM = 0.63; IL-1 + SP600125 50 μM = 0.49). However, PD98059 did not decrease MMP1 expression to baseline (GAPDH-normalized MMP1 gene expression for medium = 0.43; IL-1 = 1.40; IL-1 + PD98059 10 μM = 1.15; IL-1 + PD 98059 100 μM = 0.86).