Blood vessels have a fundamental role in transporting oxygen and nutrients to support the metabolic demands of tissues. Many blood vessels form through the process of angiogenesis, when endothelial cells lining pre-existing vessels become activated to form new vascular sprouts. New vascular sprouts grow through cell proliferation, elongation and polarised collective cell migration. In order to generate an interconnected network of blood vessels, endothelial cells fuse through the process of anastomosis. Concomitantly, the process of lumen formation takes place to render blood vessels functional. Thus, endothelial cells exhibit a multitude of cellular processes that are tightly coordinated during vessel development.
Endothelial cells are highly plastic in their ability to change their morphology to drive specific cellular processes. In order to understand how this plasticity is achieved, we investigate how the actin cytoskeleton regulates endothelial membrane dynamics during angiogenesis. During the expansion of blood vessels, the generation of actin bundles in filopodia facilitates efficient collective cell migration and anastomosis. During lumen formation, transient polymerization of F-actin at the apical membranes controls lumen expansion, while a stable pool of actin cables at endothelial cell-cell junctions stabilizes newly-formed tubules to produce a functional vascular network. In addition, recent work from the lab suggests a role of cortical actin cytoskeleton in maintaining endothelial cell shape and vessel architecture when subjected to the deforming forces of blood flow. Our work therefore demonstrates a multifaceted role of actin cytoskeleton in driving distinct steps of vessel morphogenesis.