Fig. 1.
Effect of inhibiting p38 pathway on IL-8 mRNA stability in cystic fibrosis (CF) lung epithelial cells. IB3-1 cells (A) or IB3-1-TTP cells (B) were treated with the chemical inhibitor SB-203580 (10 μM) or transiently transfected with dominant negatives (p38-AGF, MK-EE, and MK2-KR; ∼1 μg/1.5 × 106 cells) for p38-MAPK signaling pathway. RNA was isolated from IB3-1 and IB3-1-TTP cells after actinomycin D (5 μg/ml) treatment for the indicated time intervals, and the remaining mRNA was analyzed by quantitative real-time PCR. The data reflect averages of at least 3 independent experiments (*P < 0.05 and **P > 0.05). C: IL-8 protein secreted by both cell types was analyzed by ELISA 16 h after transfection. D: the phospho-p38 protein levels were analyzed by Western blot.