FIGURE 6.
MEK-ERK inhibitor, PD98059 (25 μM) decreased CCL11 mRNA and protein expression through down-regulation of STAT-6 phosphorylation. Fibroblasts were serum deprived, then pretreated for 1 h with PD98059 followed by stimulation with IL-13 and TGF-β1 plus IL-13 for 24 h to measure CCL11 mRNA and 48 h to measure CCL11 protein. A, PD98059 decreased phosphorylation of ERK and STAT-6 at 15 h, especially in the presence of TGF-β1 plus IL-13 (n=5). Right-hand side shows the relative density of p-STAT-6/STAT-6 in the presence of IL-13 and TGF-β1 plus IL-13, either with or without PD98059. ** p<0.01. B, PD98059 significantly decreased CCL11 mRNA expression in the presence of IL-13 and TGF-β1 plus IL-13 (n=9). * p<0.05; ** p<0.01. C, PD98059 significantly decreased CCL11 protein in the presence of IL-13 and TGF-β1 plus IL-13 (n=5). * p<0.05.