Figure 13.

Shear stress induces the subcellular structures of ECs to undergo rapid and significant patterns of structural dynamics that vary with cell density. In subconfluent cells, flow onset increases actin polymerization at cell edges, changes the direction of lateral stress fiber (blue, dashed-blue) displacement, reduces the centripetal remodeling of actin stress fibers (blue) and adhesion sites (green), and reduces the displacement of the underlying fibronectin matrix (red). Over time, the new actin polymerization becomes polarized in the downstream direction, and new adhesion sites stabilize the cells at sites of downstream lamellipod formation. In confluent cells, flow onset generates a rapid and transient burst of edge ruffling and a transient downstream displacement of the subcellular structures. As time progresses, the displacement patterns evolve to become more heterogeneous.