Figure 5.

Expression of MUC5AC and activation of TMEM16A in Calu-3 airway epithelial cells is inhibited by niclosamide. (A) Expression of MUC5AC induced by IL-13 (20 ng/mL; 72 h) in Calu-3 airway epithelial cells was inhibited by simultaneous incubation with niclosamide (1 µM). Bar = 100 µm. (B) Quantification of MUC5AC expression indicating inhibition by niclosamide (Niclo). (C) Current overlays from whole-cell patch clamp experiments before and after induction of MUC5AC expression by IL-13. Activation of whole-cell currents by purinergic stimulation (ATP, 100 µM) was enhanced by IL-13, which was completely inhibited by acute application of niclosamide (1 µM). (D) Corresponding current/voltage relationships. The inhibitor of Ca²⁺-activated KCNN4 K⁺ channels, TRAM-34 (100 nM), was present in all patch clamp experiments to avoid potential activation of Ca²⁺-activated K⁺ channels. Mean ± SEM (number of cells). * significant activation by ATP (p < 0.05, paired t-test). # significant difference when compared to the absence of IL-13 (p < 0.05, unpaired t-test).