Parallel activation of Ca2+-induced survival and death pathways in cardiomyocytes by sorbitol-induced hyperosmotic stress
Parallel activation of Ca2+-induced survival and death pathways in cardiomyocytes by sorbitol-induced hyperosmotic stress
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DOI：
10.1007/s10495-010-0505-9
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发表时间：
2010-08-01
期刊：
影响因子：
7.2
通讯作者：
Lavandero, S.
中科院分区：
文献类型：
--
作者：
Chiong, M.;Parra, V.;Lavandero, S.
高渗应激促进培养的心肌细胞快速和明显的凋亡。在这里，我们研究了Ca 2+信号是否有助于这种反应。将心肌细胞暴露于山梨醇[600 mosmol（kg水）（-1）]引起细胞内Ca 2+浓度的大幅度和振荡性增加。这些Ca ~（2+）信号被硝苯地平、Cd ~（2+）、U 73122、xestospongin C和ryanodine所抑制，表明这两种信号都是由电压依赖性L型Ca ~（2+）通道的Ca ~（2+）内流和由IP ~（3+）受体和ryanodine受体介导的胞内钙库的Ca ~（2+）释放共同作用的。高渗应激也增加线粒体Ca 2+水平，促进线粒体去极化，降低细胞内ATP含量，并激活转录因子环AMP反应元件结合蛋白（CREB），增加CREB磷酸化和电泳迁移率变化测定。与1 mM EGTA孵育，以减少细胞外[Ca 2 +]防止高渗应激诱导的心肌细胞凋亡，而过表达的腺病毒显性负性形式的CREB废除了1 mM EGTA提供的心脏保护。这些结果表明，山梨醇诱导的高渗胁迫，通过增加Ca 2+内流和提高细胞内Ca 2+浓度，激活Ca 2+从商店释放，并通过线粒体功能崩溃导致细胞死亡。此外，本研究结果表明，高渗应激诱导的Ca 2+增加通过招募CREB介导的信号传导促进细胞存活。因此，心肌细胞在高渗应激下的命运将取决于Ca 2+诱导的存活和死亡途径之间的平衡。
Hyperosmotic stress promotes rapid and pronounced apoptosis in cultured cardiomyocytes. Here, we investigated if Ca2+ signals contribute to this response. Exposure of cardiomyocytes to sorbitol [600 mosmol (kg water)(-1)] elicited large and oscillatory intracellular Ca2+ concentration increases. These Ca2+ signals were inhibited by nifedipine, Cd2+, U73122, xestospongin C and ryanodine, suggesting contributions from both Ca2+ influx through voltage dependent L-type Ca2+ channels plus Ca2+ release from intracellular stores mediated by IP3 receptors and ryanodine receptors. Hyperosmotic stress also increased mitochondrial Ca2+ levels, promoted mitochondrial depolarization, reduced intracellular ATP content, and activated the transcriptional factor cyclic AMP responsive element binding protein (CREB), determined by increased CREB phosphorylation and electrophoretic mobility shift assays. Incubation with 1 mM EGTA to decrease extracellular [Ca2+] prevented cardiomyocyte apoptosis induced by hyperosmotic stress, while overexpression of an adenoviral dominant negative form of CREB abolished the cardioprotection provided by 1 mM EGTA. These results suggest that hyperosmotic stress induced by sorbitol, by increasing Ca2+ influx and raising intracellular Ca2+ concentration, activates Ca2+ release from stores and causes cell death through mitochondrial function collapse. In addition, the present results suggest that the Ca2+ increase induced by hyperosmotic stress promotes cell survival by recruiting CREB-mediated signaling. Thus, the fate of cardiomyocytes under hyperosmotic stress will depend on the balance between Ca2+-induced survival and death pathways.