Central Role of Calcium-Dependent Tyrosine Kinase PYK2 in Endothelial Nitric Oxide Synthase–Mediated Angiogenic Response and Vascular Function

Abstract

Background— The involvement of Ca 2+ -dependent tyrosine kinase PYK2 in the Akt/endothelial NO synthase pathway remains to be determined. Methods and Results— Blood flow recovery and neovessel formation after hind-limb ischemia were impaired in PYK2 −/− mice with reduced mobilization of endothelial progenitors. Vascular endothelial growth factor (VEGF)–mediated cytoplasmic Ca 2+ mobilization and Ca 2+ -independent Akt activation were markedly decreased in the PYK2-deficient aortic endothelial cells, whereas the Ca 2+ -independent AMP-activated protein kinase/protein kinase-A pathway that phosphorylates endothelial NO synthase was not impaired. Acetylcholine-mediated aortic vasorelaxation and cGMP production were significantly decreased. Vascular endothelial growth factor–dependent migration, tube formation, and actin cytoskeletal reorganization associated with Rac1 activation were inhibited in PYK2-deficient endothelial cells. PI3-kinase is associated with vascular endothelial growth factor–induced PYK2/Src complex, and inhibition of Src blocked Akt activation. The vascular endothelial growth factor–mediated Src association with PLCγ1 and phosphorylation of 783 Tyr-PLCγ1 also were abolished by PYK2 deficiency. Conclusion— These findings demonstrate that PYK2 is closely involved in receptor- or ischemia-activated signaling events via Src/PLCγ1 and Src/PI3-kinase/Akt pathways, leading to endothelial NO synthase phosphorylation, and thus modulates endothelial NO synthase–mediated vasoactive function and angiogenic response.