Role of the Calcium-Sensing Receptor in Cardiomyocyte Apoptosis via the Sarcoplasmic Reticulum and Mitochondrial Death Pathway in Cardiac Hypertrophy and Heart Failure
Role of the Calcium-Sensing Receptor in Cardiomyocyte Apoptosis via the Sarcoplasmic Reticulum and Mitochondrial Death Pathway in Cardiac Hypertrophy and Heart Failure
复制标题
钙敏感受体在心肌肥厚和心力衰竭中通过肌浆网和线粒体死亡途径的心肌细胞凋亡中的作用
DOI：
10.1159/000350091
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发表时间：
2013-01-01
影响因子：
--
通讯作者：
Zhang, Wei-Hua
中科院分区：
文献类型：
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作者：
Lu, Fang-Hao;Fu, Song-Bin;Zhang, Wei-Hua
目的：心肌细胞的细胞内/肌浆网（ER/SR）和线粒体中钙稳态的改变通过SR和线粒体凋亡途径引起细胞死亡，从而导致心室功能障碍。然而，钙敏感受体（CaR）在心肌肥厚和心力衰竭中的作用尚未研究。本研究在心力衰竭的实验模型中检查了CaR在SR和线粒体凋亡途径中的可能参与。方法和结果：Wistar大鼠皮下注射异丙肾上腺素（Iso），造成心肌肥厚和心力衰竭。CaR激活剂Calindol和CaR抑制剂calhex231通过尾静脉注射给药。然后分析这些大鼠的心脏重构和左心室功能。Iso给药后2、4、6和8周，大鼠出现心肌肥厚和心力衰竭。在衰竭心脏中，ER分子伴侣和相关凋亡蛋白的心脏表达显著增加。此外，ER伴侣蛋白的表达和凋亡率也随着calindol的给药而增加，而这些蛋白的表达随着calhex 231的处理而减少。我们还通过小鼠胸主动脉缩窄（TAC）诱导心脏肥大和衰竭。TAC治疗2周和4周后，小鼠心脏ER伴侣蛋白和凋亡蛋白的表达增加。此外，Iso诱导培养的心肌细胞的ER应激和凋亡，而预处理与calhex231防止ER应激和保护心肌细胞免于凋亡。为了进一步研究CaR对细胞内钙浓度的影响，使用Fluo-5N和x-rhod-1测定SR和线粒体中的钙浓度，并使用JC-1使用激光共聚焦显微镜检查线粒体膜电位。Iso处理48 h后，CaR的激活使[Ca2 +] SR减少，[Ca2 +] m增加，线粒体膜电位降低，内质网应激分子伴侣及相关凋亡蛋白表达增加，细胞色素c从线粒体释放。结论：我们的结果表明，CaR激活导致Ca 2+从SR释放到线粒体中，并通过衰竭心脏的SR和线粒体凋亡途径诱导心肌细胞凋亡。
Aims: Alterations in calcium homeostasis in the intracellular endo/sarcoplasmic reticulum (ER/SR) and mitochondria of cardiomyocytes cause cell death via the SR and mitochondrial apoptotic pathway, contributing to ventricular dysfunction. However, the role of the calcium-sensing receptor (CaR) in cardiac hypertrophy and heart failure has not been studied. This study examined the possible involvement of CaR in the SR and mitochondrial apoptotic pathway in an experimental model of heart failure. Methods and Results: In Wistar rats, cardiac hypertrophy and heart failure were induced by subcutaneous injection of isoproterenol (Iso). Calindol, an activator of CaR, and calhex231, an inhibitor of CaR, were administered by caudal vein injection. Cardiac remodeling and left ventricular function were then analyzed in these rats. After 2, 4, 6 and 8 weeks after the administration of Iso, the rats developed cardiac hypertrophy and failure. The cardiac expression of ER chaperones and related apoptotic proteins was significantly increased in the failing hearts. Furthermore, the expression of ER chaperones and the apoptotic rate were also increased with the administration of calindol, whereas the expression of these proteins was reduced with the treatment of calhex231. We also induced cardiac hypertrophy and failure via thoracic aorta constriction (TAC) in mice. After 2 and 4 weeks of TAC, the expression of ER chaperones and apoptotic proteins were increased in the mouse hearts. Furthermore, Iso induced ER stress and apoptosis in cultured cardiomyocytes, while pretreatment with calhex231 prevented ER stress and protected the myocytes against apoptosis. To further investigate the effect of CaR on the concentration of intracellular calcium, the calcium concentration in the SR and mitochondria was determined with Fluo-5N and x-rhod-1 and the mitochondrial membrane potential was examined with JC-1 using laser confocal microscopy. After treatment with Iso for 48 hours, activation of CaR reduced [Ca2+]SR, increased [Ca2+]m, decreased the mitochondrial membrane potential, increased the expression of ER stress chaperones and related apoptotic proteins, and induced the release of cytochrome c from the mitochondria. Conclusions: Our results demonstrated that CaR activation caused Ca2+ release from the SR into the mitochondria and induced cardiomyocyte apoptosis through the SR and mitochondrial apoptotic pathway in failing hearts.