Figure 4.

IL-13 downregulates ezrin expression in bronchial epithelial cells via the JAK2 (Janus tyrosine kinase 2)/STAT6 (signal transducer and activator of transcription) pathway. (A) 16HBE cells were treated with IL-4 (20 ng/ml), IL-13 (30 ng/ml), and TNF-α (10 ng/ml) for 2, 6, and 12 hours, and ezrin mRNA expression was measured by quantitative RT-PCR. (B) 16HBE cells were exposed to IL-4 (20 ng/ml), IL-13 (30 ng/ml), and TNF-α (10 ng/ml) for 24, 48, and 72 hours, and ezrin protein production was determined by Western blotting. (C) Primary bronchial epithelial cells (PBECs) were stimulated with IL-13 (30 ng/ml) for 24, 48, and 72 hours. Ezrin protein was evaluated by Western blotting. PBECs were pretreated with the JAK2 inhibitor TG101348 (30 nM) for 1 hour before IL-13 (30 ng/ml) stimulation (1 h). The total phospho (p)-JAK2 protein level and p-STAT6 protein level in the nucleus were measured by Western blotting. The effect of TG101348 pretreatment on IL-13–regulated ezrin expression was evaluated by Western blotting. Data are presented as mean ± SEM of three independent experiments using one-way ANOVA followed by Student-Newman-Keuls post hoc analysis. ns = not significant. *P < 0.05, **P < 0.01 and ***P < 0.001, compared with control (Ctrl). TNF-α = tumor necrosis factor-α.