Pharmacological rescue of mutant CFTR protein improves the viscoelastic properties of CF mucus

BackgroundIn CF patients, the defective ion transport causes a simultaneous reduction of fluid, Cl− and HCO3− secretion. We aimed to demonstrate that the resulting altered properties of mucus can be recovered using lumacaftor, a CFTR corrector.MethodsThe micro-rheology of non-CF and CF mucus was analysed using Multiple Particle Tracking.ResultsThe diffusion coefficient of nano-beads imbedded in mucus from CF human bronchial epithelium was lower than in non-CF mucus, and the elastic and viscous moduli were higher. We found that 25% correction of F508del-CFTR mutation with lumacaftor was enough to improve significantly CF mucus properties. Surprisingly, also incubation with amiloride, a compound that reduces fluid absorption but might not change the secretion of HCO3− towards the airway surface fluid, improved CF mucus properties.ConclusionCF mucus properties can be recovered by either improving the hydration of the airways or recovering Cl− and HCO3− secretion across the mutated protein treated with a corrector compound.