The researchers analysed the sphingolipids (SLs) composition by biochemical SL procedures, the phosphorylation state of ezrin and the expression of NHERF1 in CF bronchial epithelial cell lines, treated or not with VX-809 (corrector) and VX-770 (potentiator) by Western Blot. They also evaluated the SL pattern of lipid rafts and further experiments were conducted to investigate the effect of Ganglioside 1 (GM1) on CFTR function by fluorescent probes. In CF cells treated with VX-809 and VX-770, they found an important reduction of phosphorylated ezrin, NHERF1 expression and only modest differences in the SL pattern, whereas a marked increase of all SL species in lipid rafts. Interestingly, treatment with GM1 abolished the negative effect of VX-770.
These results indicate that combined treatment with corrector/potentiator induces modification in lipid rafts organization in terms of proteins and lipids, and that GM1 is able to restore the stability of mutated rescued CFTR at PM level.