Na+/K+-ATPase inhibition by ouabain induces CaMKII-dependent apoptosis in adult rat cardiac myocytes
Na+/K+-ATPase inhibition by ouabain induces CaMKII-dependent apoptosis in adult rat cardiac myocytes
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DOI：
10.1016/j.yjmcc.2010.04.013
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发表时间：
2010-09-01
影响因子：
5
通讯作者：
Petroff, Martin Vila
中科院分区：
文献类型：
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作者：
Sapia, Luciana;Palomeque, Julieta;Petroff, Martin Vila
通过Na+/K+-ATP酶抑制产生的正性肌力作用已用于心力衰竭的治疗超过200年。最近，已显示给予毒性剂量的哇巴因可诱导心肌细胞凋亡。然而，长期服用无毒剂量的哇巴因是否也会促进心肌细胞死亡还没有被探索过。本研究的目的是评估无毒剂量的哇巴因是否可以诱导心肌细胞凋亡，如果是这样的话，检查潜在的机制。为此目的，在存在或不存在2 μ M（大鼠）和25 nm-2 μ M哇巴因（猫）的情况下，将来自大鼠和猫（对洋地黄具有不同敏感性的两个物种）的心肌细胞培养24小时。细胞活力和凋亡测定表明，哇巴因在大鼠中由于凋亡（增强的半胱天冬酶-3活性，增加的Bax/Bcl-2和TUNEL阳性核）和坏死（LDH释放和台盼蓝染色）导致细胞活力降低43 +/- 5%。在猫中使用25 nM哇巴因获得了类似的结果。哇巴因诱导的细胞活力降低被NCX抑制剂KB-R7943和CaMKII抑制剂KN 93和AIP阻止。此外，CaMKII过表达加剧哇巴因诱导的细胞死亡率，而在慢性CaMKII抑制的转基因小鼠中，这一点反而降低。然而，KN 93未能影响哇巴因诱导的肌力。此外，虽然用PD-98059抑制ERK 1/2对细胞死亡率没有影响，但用渥曼青霉素抑制PI 3 K会加剧肌细胞死亡。我们得出结论，哇巴因触发凋亡级联反应，涉及NCX和CaMKII作为下游效应。哇巴因同时激活涉及PI 3 K/AKT的抗凋亡级联反应，然而，这不足以完全抑制凋亡。KN 93阻止哇巴因诱导的细胞凋亡而不影响正性肌力的发现表明CaMKII抑制剂作为洋地黄治疗心血管疾病的辅助剂的潜在用途。(C)2010爱思唯尔有限公司版权所有。
The positive inotropic effect produced by Na+/K+-ATPase inhibition has been used for the treatment of heart failure for over 200 years. Recently, administration of toxic doses of ouabain has been shown to induce cardiac myocyte apoptosis. However, whether prolonged administration of non-toxic doses of ouabain can also promote cardiac myocyte cell death has never been explored. The aim of this study was to assess whether non-toxic doses of ouabain can induce myocyte apoptosis and if so, to examine the underlying mechanisms. For this purpose, cardiac myocytes from rat and cat, two species with different sensitivity to digitalis, were cultured for 24 h in the presence or absence of 2 mu M (rat) and 25 nm-2 mu M ouabain (cat). Cell viability and apoptosis assays showed that ouabain produced, in the rat, a 43 +/- 5% decrease in cell viability due to apoptosis (enhanced caspase-3 activity, increased Bax/Bcl-2 and TUNEL-positive nuclei) and necrosis (LDH release and trypan blue staining). Similar results were obtained with 25 nM ouabain in the cat. Ouabain-induced reduction in cell viability was prevented by the NCX inhibitor KB-R7943 and by the CaMKII inhibitors, KN93 and AIP. Furthermore, CaMKII overexpression exacerbated ouabain-induced cell mortality which in contrast was reduced in transgenic mice with chronic CaMKII inhibition. However, KN93 failed to affect ouabain-induced inotropy. In addition, whereas ERK1/2 inhibition with PD-98059 had no effect on cell mortality, PI3K inhibition with wortmannin, exacerbated myocyte death. We conclude that ouabain triggers an apoptotic cascade that involves NCX and CaMKII as a downstream effector. Ouabain simultaneously activates an antiapoptotic cascade involving PI3K/AKT which is however, insufficient to completely repress apoptosis. The finding that KN93 prevents ouabain-induced apoptosis without affecting inotropy suggests the potential use of CaMKII inhibitors as an adjunct to digitalis treatment for cardiovascular disease. (C) 2010 Elsevier Ltd. All rights reserved.