The antithrombotic effect of angiotensin-(1-7) involves mas-mediated NO release from platelets
The antithrombotic effect of angiotensin-(1-7) involves mas-mediated NO release from platelets
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DOI：
10.2119/2007-00073.fraga-silva
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发表时间：
2008-01-01
影响因子：
5.7
通讯作者：
Souza Santos, Robson Augusto
中科院分区：
文献类型：
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作者：
Fraga-Silva, Rodrigo Araujo;Brant Pinheiro, Sergio Veloso;Souza Santos, Robson Augusto
血管紧张素(Ang)-(1-7)的抗血栓作用已有报道，但其作用机制尚不清楚。我们研究了血小板和受体mass相关机制在这一作用中的参与。我们使用Western blotting检测大鼠血小板中Mas蛋白的存在，并使用荧光标记FAM-Ang-(1-7)来确定大鼠血小板和Mas（-/-）和Mas（+/+）小鼠血小板中Ang-(1-7)的特异性结合及其被受体Mas拮抗剂A-779取代。为了检测Ang-(1-7)是否诱导血小板释放NO，我们使用NO指标DAF-FM。此外，我们还研究了Mas在雄性Mas（-/-）和Mas（+/+）小鼠腔静脉诱导血栓的Ang（1-7）抗血栓作用中的作用。通过测定Mas（+/+）和Mas（-/-）小鼠的出血时间来评估Mas在止血中的功能相关性。我们通过Western Blot观察到血小板中存在Mas蛋白，并且A-779取代了荧光Ang-(1-7)与大鼠血小板的结合。此外，在Mas（+/+）小鼠血小板中，我们发现了Ang-(1-7)的特异性结合，而在Mas（-/-）小鼠血小板中没有。Ang-(1-7)从大鼠和Mas（+/+）小鼠的血小板中释放NO，而A-779阻断了这一作用。在Mas（-/-）小鼠血小板中，Ang-(1-7)刺激的NO释放被消除。Ang-(1-7)抑制Mas（+/+）小鼠血栓形成。引人注目的是，这种效应在Mas（-/-）小鼠中被消除了。此外，Mas缺乏导致出血时间显著缩短（8.50 +/- 1.47 vs. 4.28 +/- 0.66 min）。这项研究首次证实了Mas蛋白在大鼠和小鼠血小板中存在，并与Ang-(1-7)特异性结合。我们的数据还表明，Ang-(1-7)抗血栓作用涉及mas介导的血小板NO释放。更重要的是，我们发现Ang-(1-7)在体内的抗血栓作用依赖于Mas，并且Mas在止血中具有重要的功能。
The antithrombotic effect of angiotensin(Ang)-(1-7) has been reported, but the mechanism of this effect is not known. We investigated the participation of platelets and receptor Mas-related mechanisms in this action. We used Western blotting to test for the presence of Mas protein in rat platelets and used fluorescent-labeled FAM-Ang-(1-7) to determine the specific binding for Ang-(1-7) and its displacement by the receptor Mas antagonist A-779 in rat platelets and in Mas(-/-) and Mas(+/+) mice platelets. To test whether Ang-(1-7) induces NO release from platelets, we used the NO indicator DAF-FM. In addition we examined the role of Mas in the Ang(1-7) antithrombotic effect on induced thrombi in the vena cava of male Mas(-/-) and Mas(+/+) mice. The functional relevance of Mas in hemostasis was evaluated by determining bleeding time in Mas(+/+) and Mas(-/-) mice. We observed the presence of Mas protein in platelets, as indicated by Western Blot, and displacement of the binding of fluorescent Ang-(1-7) to rat platelets by A-779. Furthermore, in Mas(+/+) mouse platelets we found specific binding for Ang-(1-7), which was absent in Mas(-/-) mouse platelets. Ang-(1-7) released NO from rat and Mas(+/+) mouse platelets, and A-779 blocked this effect. The NO release stimulated by Ang-(1-7) was abolished in Mas(-/-) mouse platelets. Ang-(1-7) inhibited thrombus formation in Mas(+/+) mice. Strikingly, this effect was abolished in Mas(-/-) mice. Moreover, Mas deficiency resulted in a significant decrease in bleeding time (8.50 +/- 1.47 vs. 4.28 +/- 0.66 min). This study is the first to show the presence of Mas protein and specific binding for Ang-(1-7) in rat and mouse platelets. Our data also suggest that the Ang-(1-7) antithrombotic effect involves Mas-mediated NO release from platelets. More importantly, we showed that the antithrombotic effect of Ang-(1-7) in vivo is Mas dependent and that Mas is functionally important in hemostasis.