Brett J G, Steinberg S F, deGroot P G, Nawroth P P, Stern D M
Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, New York 10032.
J Cell Biol. 1988 Jun;106(6):2109-18. doi: 10.1083/jcb.106.6.2109.
The adrenergic agonist norepinephrine is shown to stimulate endothelium to induce protein S release and degradation, leading to diminished anti-coagulant activity and to down-regulation of protein S cell surface-binding sites. Norepinephrine-induced release of intracellular protein S was blocked by the alpha 1-adrenergic antagonist prazosin (10(-7) M) but not by the alpha-adrenergic antagonist propranolol (10(-6) M) or the alpha 2-adrenergic antagonist yohimbine (10(-5) M) indicating that this response resulted from the specific interaction of norepinephrine with a class of alpha 1-adrenergic receptors not previously observed on endothelium. Attenuation of norepinephrine-induced release of protein S by pertussis toxin in association with the ADP-ribosylation of a 41,000-D membrane protein indicates that this intracellular transduction pathway involves a regulatory G protein. The observation that protein S was released from endothelium in response to maneuvers which elevate intracellular calcium or activate protein kinase C suggests that the response may be mediated via intermediates generated through the hydrolysis of phosphoinositides. Morphologic studies were consistent with a mechanism in which norepinephrine causes exocytosis of vesicles containing protein S. In addition to release of protein S, norepinephrine also induced loss of endothelial cell protein S-binding sites, thereby blocking effective activated protein C-protein S-mediated factor Va inactivation on the cell surface. Norepinephrine-mediated endothelial cell stimulation thus results in loss of intracellular protein S and suppression of cell surface-binding sites, modulating the anti-coagulant protein C pathway on the vessel wall. These studies define a new relationship between an anti-coagulant mechanism and the autonomic nervous system, and indicate a potential role for an heretofore unrecognized class of alpha 1-adrenergic receptors in the regulation of endothelial cell physiology.
肾上腺素能激动剂去甲肾上腺素可刺激内皮细胞诱导蛋白S释放和降解，导致抗凝活性降低以及蛋白S细胞表面结合位点下调。去甲肾上腺素诱导的细胞内蛋白S释放被α1肾上腺素能拮抗剂哌唑嗪（10^(-7) M）阻断，但不被α肾上腺素能拮抗剂普萘洛尔（10^(-6) M）或α2肾上腺素能拮抗剂育亨宾（10^(-5) M）阻断，这表明该反应是由去甲肾上腺素与一类以前在内皮细胞上未观察到的α1肾上腺素能受体的特异性相互作用引起的。百日咳毒素与41,000-D膜蛋白的ADP-核糖基化相关联，减弱了去甲肾上腺素诱导的蛋白S释放，这表明该细胞内转导途径涉及一种调节性G蛋白。蛋白S因细胞内钙升高或蛋白激酶C激活的操作而从内皮细胞释放的观察结果表明，该反应可能通过磷脂酰肌醇水解产生的中间体介导。形态学研究与去甲肾上腺素导致含蛋白S的囊泡胞吐的机制一致。除了蛋白S的释放外，去甲肾上腺素还诱导内皮细胞蛋白S结合位点的丧失，从而阻断细胞表面有效激活的蛋白C-蛋白S介导的因子Va失活。因此，去甲肾上腺素介导的内皮细胞刺激导致细胞内蛋白S的丧失和细胞表面结合位点的抑制，调节血管壁上的抗凝蛋白C途径。这些研究定义了一种抗凝机制与自主神经系统之间的新关系，并表明一类迄今未被认识的α1肾上腺素能受体在调节内皮细胞生理中具有潜在作用。
