The role of endoplasmic reticulum in cadmium-induced mesangial cell apoptosis
The role of endoplasmic reticulum in cadmium-induced mesangial cell apoptosis
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DOI：
10.1016/j.cbi.2009.05.004
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发表时间：
2009-09-14
影响因子：
5.1
通讯作者：
Shih, Chwen-Ming
中科院分区：
文献类型：
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作者：
Wang, Sheng-Hao;Shih, Yung-Luen;Shih, Chwen-Ming
镉是一种工业和环境污染物，影响人类和其他哺乳动物的许多器官。然而，镉诱导肾毒性的分子机制尚不清楚。在这项研究中，我们发现内质网（ER）发挥了关键作用，镉诱导系膜细胞凋亡。用Fluo-3 AM检测细胞内钙离子浓度（[Ca ~（2+）]（i））随镉处理后时间的推移而升高。与钙螯合剂BAPTA-AM联合处理能够显着抑制镉诱导的细胞凋亡。钙调神经磷酸酶是一种胞浆磷酸酶，它能够使肌醇-1，4.5-三磷酸受体（IP 3R）钙通道去磷酸化，以阻止钙从ER释放。钙调磷酸酶抑制剂环孢素A可增加[Ca ~（2+）]（i）和镉诱导的细胞凋亡百分比。然而，EGTA和IP 3R抑制剂，2-APB，能够部分调节镉的细胞毒性。这些结果提示，细胞外和内质网释放的钙在镉诱导的系膜细胞凋亡中起着至关重要的作用。根据这条线，我们进一步检测了镉处理后的ER应力，因为ER是主要的钙储存细胞器之一。镉暴露后，GADD 153，ER应激的标志。上调（暴露4小时），随后激活ER特异性caspase-12及其下游分子caspase-3（暴露16小时）。pan caspase抑制剂Z-VAD和BAPTA-AM能够分别逆转Cd诱导的细胞死亡和ER应激。此外，线粒体膜电位（Δ psi（m））的去极化显着和细胞色素c释放后，24小时暴露于镉，随后在36小时的时间点的caspase-9的轻度激活，表明线粒体应激是一个晚期事件。因此，我们得出结论，ER是镉诱导系膜细胞凋亡的主要杀伤细胞器，钙振荡起着关键作用。(C)2009爱思唯尔爱尔兰有限公司保留所有权利。
Cd is an industrial and environmental pollutant that affects many organs in humans and other mammals. However, the molecular mechanisms of Cd-induced nephrotoxicity are unclear. In this study, we show that endoplasmic reticula (ER) played a pivotal role in Cd-induced apoptosis in mesangial cells. Using Fluo-3 AM, the intracellular concentration of calcium ([Ca2+](i)) was detected as being elevated as time elapsed after Cd treatment. Co-treatment with BAPTA-AM, a calcium chelator, was able to significantly suppress Cd-induced apoptosis. Calcineurin is a cytosolic phosphatase, which was able to dephosphorylate the inositol-1,4.5-triphosphate receptor (IP3R) calcium channel to prevent the release of calcium from ER. Cyclosporine A, a calcineurin inhibitor, increased both [Ca2+](i) and the percentage of Cd-induced apoptosis. However, EGTA and the IP3R inhibitor, 2-APB, were able to partially modulate Cd cytotoxicity. These results led us to suggest that the extracellular and ER-released calcium plays a crucial role in Cd-induced apoptosis in mesangial cells. Following this line, we further detected the ER stress after Cd treatment since ER is one of the major calcium storage organelles. After Cd exposure, GADD153, a hallmark of ER stress. was upregulated (at 4h of exposure), followed by activation of ER-specific caspase-12 and its downstream molecule caspase-3 (at 16 h of exposure). The pan caspase inhibitor, Z-VAD, and BAPTA-AM were able to reverse the Cd-induced cell death and ER stress, respectively. Furthermore, the mitochondrial membrane potential (Delta psi(m)) was depolarized significantly and cytochrome c was released after 24 h of exposure to Cd and followed by mild activation of caspase-9 at the 36-h time point, indicating that mitochondria stress is a late event. Therefore, we concluded that ER is the major killer organelle in Cd-induced mesangial cell apoptosis and that calcium oscillation plays a pivotal role. (C) 2009 Elsevier Ireland Ltd. All rights reserved.