Polycystin-1 suppresses apoptotic signalling in endothelial cells and protects from atherosclerosis

Polycystin-1 (PKD1) and -2 (PKD2) are causative genes for autosomal dominant polycystic kidney disease (ADPKD), which often presents with cardiovascular manifestations by mechanisms still not completely understood. PKD1 and PKD2 have been suggested to function as mechanoreceptors in endothelial cells (ECs), transducing mechanical forces exerted by the flowing blood into downstream signalling pathways. Our zebrafish functional screening of EC mechanoreceptors identified PKD1 and PKD2 as anti-apoptotic, protective factors in the zebrafish endothelium. In mice, we show that inducible EC-specific loss of PKD1, but not PKD2, led to increased atherosclerosis. To dissect the underlying mechanisms, we performed single cell RNA sequencing and identified candidate pathways regulating EC behaviour downstream from PKD1. Knockdown of PKD1 in human aortic ECs resulted in increased EC apoptosis and decreased expression of athero-protective endothelial nitric oxide synthase (eNOS), which was mediated by thrombospondin 1 (THBS1) and cellular communication network factor 1 (CCN1). By integrating in vivo and in vitro models with –omics approaches, we have identified PKD1 as a novel regulator of EC survival and protective factor against atherosclerosis development. We conclude that therapeutic targeting of this pathway may treat atherosclerosis.