CFTR deficiency modulates the activity of endothelial mechanosensitive channels TRPV4 and PIEZO1; and drives endothelial barrier failure.

Cystic fibrosis (CF) is a life-shortening genetic disease caused by a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Despite reports of CFTR expression on endothelial cells, pulmonary vascular perturbations, and perfusion deficit in CF patients, the mechanism of pulmonary vascular disease in CF remains unclear. Here, we describe loss of small pulmonary blood vessels in CF patients with severe lung disease. Using a vessel-on-a-chip model, we establish a shear stress-dependent mechanism of endothelial barrier failure in CF involving calcium-permeable mechanosensitive channel TRPV4. Furthermore, we demonstrate that CFTR deficiency downregulates the function of PIEZO1, another calcium-permeable mechanosensitive channel involved in angiogenesis and wound repair, and further exacerbates loss of small pulmonary blood vessels. We show that CFTR directly interacts with PIEZO1 and enhances its function, and that CFTR deficiency reduces PIEZO1 activity. Our study identifies key cellular targets to mitigate loss of small pulmonary blood vessels in CF. To investigate changes in gene expression and lipid metabolism when CFTR is knocked down by siRNA