FIGURE 4.

Effect of small molecule corrector treatment C4, C18, and the combination C4 + C18 on CFTR-mediated Cl⁻ secretion in CFBE cells stably expressing WT-CFTR. A, original short-circuit current recording in untreated cells or after incubation of C4, C18, C4 + C18 (10 μm, 16 h, 37 °C) as indicated. B, corresponding ΔIsc response. Data are expressed as the CFTR_inh172 sensitive short-circuit current (ΔIsc) calculated by subtracting the Isc after CFTR_inh172 treatment from the peak forskolin/genistein-stimulated Isc. Statistical significance is presented as follows: ns, no significant difference; *, p < 0.05; **, p < 0.01; ***, p < 0.001 (n = 7 for each condition) compared with control condition (n = 7). Amiloride (100 μm) was kept during the duration of the whole experiment to avoid interference of ENaC-mediated Na⁺ currents. (WT cells are a gift from Dieter Gruenert (7).)