AMP-activated protein kinase mediates preconditioning in cardiomyocytes by regulating activity and trafficking of sarcolemmal ATP-sensitive K(+) channels.
AMP-activated protein kinase mediates preconditioning in cardiomyocytes by regulating activity and trafficking of sarcolemmal ATP-sensitive K(+) channels.
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DOI：
10.1002/jcp.20862
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发表时间：
2007-01
影响因子：
5.6
通讯作者：
Jovanovic, Aleksandar
中科院分区：
文献类型：
--
作者：
Sukhodub, Andrey;Jovanovic, Sofija;Du, Qingyou;Budas, Grant;Clelland, Allyson K;Shen, Mei;Sakamoto, Kei;Tian, Rong;Jovanovic, Aleksandar
持续性缺血之前的短暂缺血和再灌注导致心肌梗死面积减小。这种现象被称为缺血预适应，是由复杂的信号通路介导的，但尚未完全确定。AMP激活激酶（AMPK）在与ATP耗竭和AMP/ATP比率增加相关的条件下在细胞中被激活。在本研究中，我们利用过表达AMPK α2亚基显性负性形式的心脏表型来分析AMPK在心脏预处理中的作用（如果有的话）。我们已经发现心肌预处理激活野生型AMPK，而不是转基因小鼠。转基因小鼠的心脏细胞不能进行预处理，而野生型的细胞则相反。AMPK的细胞保护作用与预处理对线粒体膜电位的影响无关，如JC-1（线粒体膜电位敏感染料）和激光共聚焦显微镜所示。与此相反，实验与二-8-ANEPPS，肌膜电位敏感染料，已证明，完整的AMPK活性所需的预处理诱导缩短的动作膜电位。在野生型小鼠中观察到预处理诱导的肌膜KATP通道激活，但在转基因小鼠中未观察到。HMR 1098是一种选择性肌膜KATP通道开放抑制剂，可抑制预处理引起的动作膜电位缩短以及AMPK提供的心脏保护作用。免疫沉淀，然后Western印迹表明，AMPK是必不可少的预处理诱导的招聘肌膜KATP通道。基于所获得的结果，我们得出结论，AMPK介导的预处理心肌细胞通过调节的活性和招聘的肌膜KATP通道，而不是一个信号通路的一部分，调节线粒体膜电位。
Brief periods of ischemia and reperfusion that precede sustained ischemia lead to a reduction in myocardial infarct size. This phenomenon, known as ischemic preconditioning, is mediated by signaling pathway(s) that is complex and yet to be fully defined. AMP-activated kinase (AMPK) is activated in cells under conditions associated with ATP depletion and increased AMP/ATP ratio. In the present study, we have taken advantage of a cardiac phenotype overexpressing a dominant negative form of the α2 subunit of AMPK to analyze the role, if any, that AMPK plays in preconditioning the heart. We have found that myocardial preconditioning activates AMPK in wild type, but not transgenic mice. Cardiac cells from transgenic mice could not be preconditioned, as opposed to cells from the wild type. The cytoprotective effect of AMPK was not related to the effect that preconditioning has on mitochondrial membrane potential as revealed by JC-1, a mitochondrial membrane potential-sensitive dye, and laser confocal microscopy. In contrast, experiments with di-8-ANEPPS, a sarcolemmal-potential sensitive dye, has demonstrated that intact AMPK activity is required for preconditioning-induced shortening of the action membrane potential. The preconditioning-induced activation of sarcolemmal KATP channels was observed in wild type, but not in transgenic mice. HMR 1098, a selective inhibitor of sarcolemmal KATP channels opening, inhibited preconditioning-induced shortening of action membrane potential as well as cardioprotection afforded by AMPK. Immunoprecipitation followed by Western blotting has shown that AMPK is essential for preconditioning-induced recruitment of sarcolemmal KATP channels. Based on the obtained results, we conclude that AMPK mediates preconditioning in cardiac cells by regulating the activity and recruitment of sarcolemmal KATP channels without being a part of signaling pathway that regulates mitochondrial membrane potential.