Endothelial alpha-parvin controls integrity of developing vasculature and is required for maintenance of cell-cell junctions.

RATIONALE

Angiogenesis and vessel integrity depend on the adhesion of endothelial cells (ECs) to the extracellular matrix and to adjacent ECs. The focal adhesion protein α-parvin (α-pv) is essential for vascular development. However, the role of α-pv in ECs in vivo is not known.

OBJECTIVE

To determine the function of α-pv in ECs during vascular development in vivo and the underlying mechanisms.

METHODS AND RESULTS

We deleted the α-pv gene specifically in ECs of mice to study its role in angiogenesis and vascular development. Here, we show that endothelial-specific deletion of α-pv in mice results in late embryonic lethality associated with hemorrhages and reduced vascular density. Postnatal-induced EC-specific deletion of α-pv leads to retinal hypovascularization because of reduced vessel sprouting and excessive vessel regression. In the absence of α-pv, blood vessels display impaired VE-cadherin junction morphology. In vitro, α-pv-deficient ECs show reduced stable adherens junctions, decreased monolayer formation, and impaired motility, associated with reduced formation of integrin-mediated cell-extracellular matrix adhesion structures and an altered actin cytoskeleton.

CONCLUSIONS

Endothelial α-pv is essential for vessel sprouting and for vessel stability.