Cytoskeletal regulation of endothelial barrier function within an endothelial cell (EC). Under inflammatory conditions, mediators such as the bioactive lipid LPA, thrombin, vascular endothelial growth factor (VEGF), transforming growth factor (TGF)β, angiotensin 1 and 2, and multiple cytokines including interleukin (IL)-8 and IL-10 are increased. These ligands interact with EC surface receptors to induce changes in the cellular cytoskeleton. One of the effects of injury on the EC are increased contractile forces generated via the formation of actin stress fibres, predominate and lead to paracellular gap formation and loss of barrier integrity.