Abstract 818: Central Role of Calcium-Dependent Tyrosine Kinase PYK2 in eNOS-Mediated Angiogenesis Unmasked by PYK2 Knockout Mice
Background: Endothelial nitric oxide synthase (eNOS) is activated by Akt or Ca2+-dependent CaM kinases, whereas the involvement of Ca2+-dependent tyrosine kinase PYK2 remains to be determined.
Methods and Results: We newly generated the PYK2-deficient mice and investigated the effects of PYK2 on NO-mediated vascular functions and angiogenic response. The PYK2−/− mice exhibited a significant reduction in the basal eNOS phosphorylation and VEGF- or Acetylcholin-mediated response in the aorta and aortic endothelial cells (ECs) compared with the wild-type mice, and blood flow recovery and neovessel formation after hindlimb ischemia were reduced without affecting mobilization of endothelial progenitors and EC differentiation. VEGF-mediated Akt phosphorylation, NO production and cytoplasmic Ca2+ mobilization were markedly decreased. Acetylcholin-mediated aortic vasorelaxation and cGMP production were decreased (54% and 44%, P<0.01, respectively) and blood pressure in the PYK2−/− mice is higher than the wild-type mice (mean 80 vs. 74 mmHg, P<0.05). VEGF-dependent migration, tube formation and actin cytoskeletal reorganization were markedly inhibited in PYK2−/− ECs, while addition of L-arginine or cGMP-dependent kinase activator reversed the attenuated response.
Conclusion: These findings demonstrate that PYK2 is involved in the receptor-activated signalling events leading to the phosphorylation of eNOS/Akt and thus regulates eNOS-mediated vasoactive function and angiogenic response.