Shear stress mechanotransduction by transition of plasma membrane lipid order in vascular endothelial cells

Abstract

Endothelial cells (ECs) sense shear stress and transduce its information into functional responses that play important roles in vascular homeostasis. A unique feature of shear-stress-sensing is the involvement of many membrane-bound-molecules, but the mechanisms remain unknown. Because cell membrane-bound properties affect the activities of membrane-bound proteins, shear stress may activate various membrane-bound molecules by altering the physical properties of EC membranes. To determine how shear stress influences the cell membrane, cultured ECs were exposed to shear stress and examined for changes in membrane lipid order by Laurdan two-photon imaging. Upon shear stress stimulation, the lipid order of membranes rapidly decreased, and caveolar membrane changed from the liquid-ordered state to the liquid-disordered state. A similar decrease in lipid order occurred when the artificial membranes were exposed to shear stress, suggesting that this is a physical phenomenon. These findings indicate that ECs identify shear stress through changes in their membrane lipid order.