Exposure of human vascular endothelial cells to sustained hydrostatic pressure stimulates proliferation. Involvement of the alphaV integrins.

The present study investigated the effects of sustained hydrostatic pressure (SHP; up to 4 cm H2O) on human umbilical vein endothelial cell (HUVEC) proliferation, focal adhesion plaque (FAP) organization, and integrin expression. Exposure of HUVECs to SHP stimulated cell proliferation and a selective increase in the expression of integrin subunit alphaV. The increase in alphaV was observed as early as 4 hours after exposure to pressure and preceded detectable increases in the bromodeoxyuridine labeling index. Laser confocal microscopy studies demonstrated colocalization of the alphaV integrin to FAPs. The individual FAPs in pressure-treated cells demonstrated a reduced area and increased aspect ratio and were localized to both peripheral and more central regions of the cells, in contrast to the predilection for the cell periphery in cells maintained under control pressure conditions. The pressure-induced changes in alphaV distribution had functional consequences on the cells: adhesivity of the cells to vitronectin was increased, and alphaV antagonists blocked the pressure-induced proliferative response. Thus, the present study suggests a role for alphaV integrins in the mechanotransduction of pressure by endothelial cells.