Analysis of Endothelial Cell Migration Under Flow

The migration of endothelial cells (ECs) play an important role in embryonic vasculogenesis, angiogenesis, and post-angioplasty reendothelialization. ECs are constantly subjected to fluid shear stress (the tangential component of hemodynamic forces) from blood flow, but the effects of shear stress on EC migration have not been well characterized until recently. We have used an in vitro flow system to apply shear stress to EC cultures and used imaging and biochemical techniques to analyze EC migration under well-defined flow conditions. Time-lapse microscopy and cell tracing analysis generated quantitative information on EC migration under flow, and this assay was used to dissect the signaling events involved in shear stress-induced EC migration. By expressing green fluorescent protein-tagged molecules in EC, cell focal adhesions and cytoskeleton were visualized and quantified in living cells under flow, which provides temporal and spatial resolution for mechanotransduction at the molecular level. The studies on EC migration under flow will advance our understandings on vascular repair and remodeling in vivo, and provide a rational basis for the development of strategy to promote endothelialization and vascularization in tissue-engineered constructs.