Piezo1 Channels in Vascular Development and the Sensing of Shear Stress.

A critical point in mammalian development occurs before mid-embryogenesis when the heart starts to beat, pushing blood into the nascent endothelial lattice. This pushing force is a signal, detected by endothelial cells as a frictional force (shear stress) to trigger cellular changes that underlie the essential processes of vascular remodeling and expansion required for embryonic growth. The processes are complex and multifactorial and Piezo1 became a recognized player only 2years ago, 4years after Piezo1's initial discovery as a functional membrane protein. Piezo1 is now known to be critical in murine embryonic development just at the time when the pushing force is first detected by endothelial cells. Murine Piezo1 gene disruption in endothelial cells is embryonic lethal and mutations in human PIEZO1 associate with severe disease phenotype due to abnormal lymphatic vascular development. Piezo1 proteins coassemble to form calcium-permeable nonselective cationic channels, most likely as trimers. They are large proteins with little if any resemblance to other proteins or ion channel subunits. The channels appear to sense mechanical force directly, including the force imposed on endothelial cells by physiological shear stress. Here, we review current knowledge of Piezo1 in the vascular setting and discuss hypotheses about how it might serve its vascular functions and integrate with other mechanisms. Piezo1 is a new important player for investigators in this field and promises much as a basis for better understanding of vascular physiology and pathophysiology and perhaps also discovery of new therapies.