Figure 6.

IL-4 and IL-17A synergize with TGF-β₁ to promote ERK1/2 activation. The 16-HBE cells were first stimulated with indicated cytokines for 5 or 60 min, and then harvested for analysis of EGFR, Smad3 and ERK1/2 activation by Western blot analysis. A. TGF-β₁, IL-4 and IL-17A failed to show a perceptible impact on EGFR activity. B. TGF-β₁ was potent to stimulate Smad3 activation as manifested by the higher levels of pSmad3, while IL-4 and IL-17A failed to induce Smad3 activation. C. A synergic action was observed between TGF-β₁, IL-4 and IL-17A on ERK1/2 activity, in which much higher levels of pERK1/2 were detected in cocktail stimulated cells as compared with that of cells stimulated with each cytokine alone.