Molecular mechanisms involved in the angiotensin-(1-7)/Mas signaling pathway in cardiomyocytes
Molecular mechanisms involved in the angiotensin-(1-7)/Mas signaling pathway in cardiomyocytes
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DOI：
10.1161/hypertensionaha.108.114280
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发表时间：
2008-09-01
期刊：
影响因子：
8.3
通讯作者：
Guatimosim, Silvia
中科院分区：
文献类型：
--
作者：
Dias-Peixoto, Marco F.;Santos, Robson A. S.;Guatimosim, Silvia
最近有越来越多的证据表明，血管紧张素-（1-7）[ Ang-（1-7）]在心脏中的有益作用是由其受体Mas介导的。然而，参与心肌细胞中这些效应的信号通路尚不清楚。在这里，我们研究了参与的Ang-（1-7）/ Mas轴在NO的产生和Ca 2+处理成人心室肌细胞使用分子生物学，细胞内Ca 2+成像，共聚焦显微镜相结合。急性Ang-（1-7）处理（10 nmol/ L）导致心肌细胞产生NO并激活内皮NO合酶和Akt。A-779（1 μ mol/ L）预处理可阻断Ang-（1-7）依赖的NO升高。为了证实Ang-（1-7）的作用是由Mas介导的，我们使用了从Mas缺陷小鼠中分离的心肌细胞。在Mas缺陷的心肌细胞中，Ang-（1-7）不能增加NO水平。此外，Mas-ablation伴随着参与内皮NO合酶活性调节的蛋白质的显著改变，表明内皮NO合酶及其结合伴侣是心肌细胞中Mas-mediated途径的重要效应子。然后我们研究了Ang-（1-7）/ Mas轴在Ca 2+信号转导中的作用。用10 nmol/ L Ang-（1-7）处理的心肌细胞未显示Ca 2+瞬时参数的变化，如峰值Ca 2+瞬时和衰减动力学。然而，与野生型心肌细胞相比，来自Mas缺陷小鼠的心肌细胞呈现降低的峰值和较慢的[Ca 2 +]（i）瞬变。在Mas缺陷的心肌细胞中，肌浆网Ca 2 + ATP酶表达水平降低伴随着Ca 2+瞬时减少。因此，慢性Mas缺乏导致心肌细胞中Ca 2+处理受损。总的来说，这些观察结果揭示了Ang-（1-7）/ Mas轴作为心肌细胞功能调节剂的关键作用。
Recently there has been growing evidence suggesting that beneficial effects of angiotensin-(1-7) [ Ang-(1-7)] in the heart are mediated by its receptor Mas. However, the signaling pathways involved in these effects in cardiomyocytes are unknown. Here, we investigated the involvement of the Ang-(1-7)/ Mas axis in NO generation and Ca2+ handling in adult ventricular myocytes using a combination of molecular biology, intracellular Ca2+ imaging, and confocal microscopy. Acute Ang-(1-7) treatment (10 nmol/ L) leads to NO production and activates endothelial NO synthase and Akt in cardiomyocytes. Ang-(1-7) -dependent NO raise was abolished by pretreatment with A-779 (1 mu mol/ L). To confirm that Ang-(1-7) action is mediated by Mas, we used cardiomyocytes isolated from Mas-deficient mice. In Mas-deficient cardiomyocytes, Ang-(1-7) failed to increase NO levels. Moreover, Mas-ablation was accompanied by significant alterations in the proteins involved in the regulation of endothelial NO synthase activity, indicating that endothelial NO synthase and its binding partners are important effectors of the Mas-mediated pathway in cardiomyocytes. We then investigated the role of the Ang-(1-7)/ Mas axis on Ca2+ signaling. Cardiomyocytes treated with 10 nmol/ L of Ang-(1-7) did not show changes in Ca2+-transient parameters such as peak Ca2+ transients and kinetics of decay. Nevertheless, cardiomyocytes from Mas-deficient mice presented reduced peak and slower [ Ca2+](i) transients when compared with wild-type cardiomyocytes. Lower Ca2+ ATPase of the sarcoplasmic reticulum expression levels accompanied the reduced Ca2+ transient in Mas-deficient cardiomyocytes. Therefore, chronic Mas-deficiency leads to impaired Ca2+ handling in cardiomyocytes. Collectively, these observations reveal a key role for the Ang-(1-7)/ Mas axis as a modulator of cardiomyocyte function.