Rationale:The neuropeptide catestatin is an endogenous nicotinic cholinergic antagonist that acts as a pleiotropic hormone.Objective: Catestatin shares several functions with angiogenic factors. We therefore reasoned that catestatin induces growth of new blood vessels. Methods and Results:Catestatin induced migration, proliferation, and antiapoptosis in endothelial cells and exerted capillary tube formation in vitro in a Matrigel assay, and such effects were mediated via G protein, mitogen-activated protein kinase, and Akt. Catestatin-induced endothelial cell functions are further mediated by basic fibroblast growth factor, as shown by blockade of effects by a neutralizing fibroblast growth factor antibody. Furthermore, catestatin released basic fibroblast growth factor from endothelial cells and stimulated fibroblast growth factor signaling. In addition to its function on endothelial cells, catestatin also exerted effects on endothelial progenitor cells and vascular smooth muscle cells. In vivo, catestatin induced angiogenesis in the mouse cornea neovascularization assay and increased blood perfusion and number of capillaries in the hindlimb ischemia model. In addition to angiogenesis, catestatin increased density of arterioles/arteries and incorporation of endothelial progenitor cells in the hindlimb ischemia model, indicating induction of arteriogenesis and postnatal vasculogenesis. Conclusion:We conclude that catestatin acts as a novel angiogenic cytokine via a basic fibroblast growth factor-dependent mechanism. (Circ Res. 2010;107:1326-1335.) Key Words: angiogenesis Ⅲ blood vessels Ⅲ endothelium Ⅲ endothelial progenitor cells C hromogranin (Cg)A, the index member of the chromogranin/secretogranin protein family, is the major soluble protein of catecholamine storage vesicles of sympathetic nerve terminals and the adrenal medulla. 1,2 CgA is a proprotein giving rise to biological active peptides like the dysglycemic hormone pancreastatin, 3 the vasodilator vasostatin, 4 and catestatin 5 (CST) ), which inhibits catecholamine release by acting as a nicotinic cholinergic antagonist, resulting in a negative-feedback mechanism. Although plasma CgA is high in human essential (hereditary) hypertension, the plasma concentration of CST is lower in both established cases and in normotensive subjects with a family history of the disease, 6 suggesting a mechanism whereby diminished CST might increase the risk for later development of hypertension. Consistent with the human findings, high blood pressure has been reported in mice after targeted ablation of the Chga gene (Chga knockout), and such high blood pressure can be "rescued" either by replacement with CST or introduction of the human ortholog in the Chga knockout background. 7 Angiogenesis, the growth of new vessels from the preexisting vasculature, is an important process in many physiological conditions including embryonic development and wound healing. However, defects in the regula- Original received February 25, 2010; revision received September 27, 2010;...

Expression of angiogenic cytokines like vascular endothelial growth factor is enhanced by hypoxia. We tested the hypothesis that decreased oxygen levels up-regulate the angiogenic factor secretoneurin. In vivo, muscle cells of mouse ischemic hind limbs showed increased secretoneurin expression, and inhibition of secretoneurin by a neutralizing antibody impaired the angiogenic response in this ischemia model. In a mouse soft tissue model of hypoxia, secretoneurin was increased in subcutaneous muscle fibers. In vitro, secretoneurin mRNA and protein were up-regulated in L6 myoblast cells after exposure to low oxygen levels. The hypoxia-dependent regulation of secretoneurin was tissue specific and was not observed in endothelial cells, vascular smooth muscle cells, or AtT20 pituitary tumor cells. The hypoxia-dependent induction of secretoneurin in L6 myoblasts is regulated by hypoxia-inducible factor-1alpha, since inhibition of this factor using si-RNA inhibited up-regulation of secretoneurin. Induction of secretoneurin by hypoxia was dependent on basic fibroblast growth factor in vivo and in vitro, and inhibition of this regulation by heparinase suggests an involvement of low-affinity basic fibroblast growth factor binding sites. In summary, our data show that the angiogenic cytokine secretoneurin is up-regulated by hypoxia in muscle cells by hypoxia-inducible factor-1alpha- and basic fibroblast growth factor-dependent mechanisms.