Morphologic responses of endothelium to shear stress: reorganization of the adherens junction.

Shear stresses induce marked morphologic responses from endothelium which include alterations to cell shape and orientation and changes to cytoskeletal organization. These morphologic changes necessitate remodeling of cell-cell adhesion complexes that are important to control of endothelial cell physiology. Reorganization of endothelial adherens junctions has been characterized, and there are some data that pertain to the signaling pathways that regulate this reorganization. Shear-induced activation of Src, mitogen-activated protein (MAP) kinase (ERK1/2 and p38), and PI 3'-kinase pathways are important candidate pathways, and there is evidence for a role for the Rho GTPases. Very little is known concerning shear-dependence of other junctional complexes, but available data indicates a high degree of shear sensitivity. Given the continuous changes in hemodynamics which occur physiologically in vivo, sensitivity of endothelial cell-cell adhesion complexes to shear will likely prove important to vascular pathophysiology.