Exposure of human vascular endothelial cells to sustained hydrostatic pressure stimulates proliferation - Involvement of the alpha(v) integrins

The present study investigated the effects of sustained hydrostatic pressur e (SHP; up to 4 cm H2O) on human umbilical vein endothelial cell (HUVEC) pr oliferation, focal adhesion plaque (FAP) organization, and integrin express ion. Exposure of HUVECs to SHP stimulated cell proliferation and a selectiv e increase in the expression of integrin subunit alpha(v). The increase in alpha(v) was observed as early as 4 hours after exposure to pressure and pr eceded detectable increases in the bromodeoxyuridine labeling index. Laser confocal microscopy studies demonstrated colocalization of the alpha(v) int egrin to FAPs. The individual FAPs in pressure-treated cells demonstrated a reduced area and increased aspect ratio and were localized to both periphe ral and more central regions of the cells, in contrast to the predilection for the cell periphery in cells maintained under control pressure condition s, The pressure-induced changes in alpha(v) distribution had functional con sequences on the cells: adhesivity of the cells to vitronectin was increase d, and alpha(v) antagonists blocked the pressure-induced proliferative resp onse, Thus, the present study suggests a role for alpha(v) integrins in the mechanotransduction of pressure by endothelial cells.