Figure 6: STAT5 is the key molecule in TSLP-induced corticosteroid resistance.

(a) Western blot analysis of phosphorylated STAT5 in the nucleus of FALC-derived NH cells cultured with IL-33 (10 ng ml⁻¹), TSLP (10 ng ml⁻¹), dexamethasone (10⁻⁸ M) or their combination for 12 h. TATA-binding protein (TBP) is shown as a loading control. (b) Levels of total and phosphorylated glucocorticoid receptor (GR) in NH cells were assessed by western blot analysis. Actin and TBP were loading controls for cytoplasmic and nuclear components, respectively. (c,d) Survival rate (PI-negative cells/total cells) of NH cells cultured with IL-33 (10 ng ml⁻¹), dexamethasone (Dex: 10⁻⁸ M) and/or TSLP (10 ng ml⁻¹) in the presence of a STAT5 inhibitor (c, compound 573108, 10–100 μM) or pimozide (d, 1 or 5 μM) for 4 days. Mean±s.e.m., n=3 for each group. *P<0.05, **P<0.01 (ANOVA, Dunnet). P-values are presented as compared with IL-33+TSLP. Data are representatives of three independent experiments.