FIGURE 4.

VX-445 potentiates temperature-rescued F508del, M1101K and N1303K cystic fibrosis transmembrane conductance regulator (CFTR) mutations in HEK293 cells. RFU: relative fluorescence units; DMSO: dimethyl sulfoxide; FSK: forskolin; EC₅₀: half-maximal effective concentration (µM). a) Representative traces of F508del-CFTR-dependent chloride efflux (membrane depolarisation assay, 3 µM S-VX-445+10 µM FSK) in HEK293 cells stably transfected with F508del-CFTR after 24 h incubation at 27°C. b–d) Dose–response curves of VX-770 or S-VX-445 (0.001–3 µM)+FSK (10 µM) in b) F508del-, c) M1101K- or d) N1303K-CFTR HEK293 cells (n=5 biological replicates and four technical replicates for each experiment). The peak changes in fluorescence to CFTR agonists were normalised relative to the baseline fluorescence (ΔF/F₀). Data are presented as mean±sd. Analysis was performed using one-way ANOVA followed by Turkey's post hoc test (*: p<0.05; **: p<0.01; ***: p<0.001).