Vasoinhibins Prevent Bradykinin-Stimulated Endothelial Cell Proliferation by Inactivating eNOS via Reduction of both Intracellular Ca²⁺ Levels and eNOS Phosphorylation at Ser¹¹⁷⁹

Author： Thebault Stéphanie González Carmen García Celina Zamarripa David Arredondo Nava Gabriel Vaca Luis López-Casillas Fernando de la Escalera Gonzalo Martínez Clapp Carmen

Publisher： MDPI

E-ISSN： 1424-8247|4|7|1052-1069

ISSN： 1424-8247

Source： Pharmaceuticals, Vol.4, Iss.7, 2011-07, pp. : 1052-1069

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Abstract

Vasoinhibins, a family of antiangiogenic peptides derived from prolactin proteolysis, inhibit the vascular effects of several proangiogenic factors, including bradykinin (BK). Here, we report that vasoinhibins block the BK-induced proliferation of bovine umbilical vein endothelial cells. This effect is mediated by the inactivation of endothelial nitric oxide synthase (eNOS), as the NO donor DETA-NONOate reverted vasoinhibin action. It is an experimentally proven fact that the elevation of intracellular Ca²⁺ levels ([Ca²⁺]_i) upon BK stimulation activates eNOS, and vasoinhibins blocked the BK-mediated activation of phospholipase C and the formation of inositol 1,4,5-triphosphate leading to a reduced release of Ca²⁺ from intracellular stores. The [Ca²⁺]_i rise evoked by BK also involves the influx of extracellular Ca²⁺ via canonical transient receptor potential (TRPC) channels. Vasoinhibins likely interfere with TRPC-mediated Ca²⁺ entry since La³⁺, which is an enhancer of TRPC4 and TRPC5 channel activity, prevented vasoinhibins from blocking the stimulation by BK of endothelial cell NO production and proliferation, and vasoinhibins reduced the BK-induced increase of TRPC5 mRNA expression. Finally, vasoinhibins prevented the BK-induced phosphorylation of eNOS at Ser¹¹⁷⁹, a post-translational modification that facilitates Ca²⁺-calmodulin activation of eNOS. Together, our data show that vasoinhibins, by lowering NO production through the inhibition of both [Ca²⁺]_i mobilization and eNOS phosphorylation, prevent the BK-induced stimulation of endothelial cell proliferation. Thus, vasoinhibins help to regulate BK effects on angiogenesis and vascular homeostasis.