TRPM2 Channels Protect against Cardiac Ischemia-Reperfusion Injury ROLE OF MITOCHONDRIA
TRPM2 Channels Protect against Cardiac Ischemia-Reperfusion Injury ROLE OF MITOCHONDRIA
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DOI：
10.1074/jbc.m113.533851
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发表时间：
2014-03-14
影响因子：
4.8
通讯作者：
Cheung, Joseph Y.
中科院分区：
文献类型：
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作者：
Miller, Barbara A.;Hoffman, Nicholas E.;Cheung, Joseph Y.
背景：TRPM 2通道存在于心脏中，但其功能尚不清楚。结果：TRPM 2基因缺失导致心肌线粒体功能障碍，ROS产生增加，加重心肌缺血损伤。结论：TRPM 2通道维持心肌线粒体生物能量，对心肌细胞缺血损伤具有保护作用。重要性：TRPM 2是治疗缺血性心脏病的理想靶点，心肌TRPM 2通道可被细胞内二磷酸腺苷-核糖激活，并被氟灭酸阻断。在成年心肌细胞中，TRPM 2通道的G（Ca）与G（Na）的比值为0.56 +/- 0.02。为了探索TRPM 2通道保护心脏缺血/再灌注（I/R）损伤的细胞机制，我们分析了WT和TRPM 2 KO心脏I/R的蛋白质组。在WT-I/R和KO-I/R心脏之间表现出最大差异的经典途径是线粒体功能障碍和三羧酸循环。与WT-I/R心脏相比，KO-I/R中复合物I、III和IV下调，而复合物II和V上调。Western印迹证实KO-I/R心脏中复合物I亚基和其他与心脏相关的蛋白质的表达减少。生物能量分析显示，KO心肌细胞具有较低的线粒体膜电位，线粒体Ca 2+摄取，ATP水平，和O-2消耗，但较高的线粒体超氧化物水平。此外，KO肌细胞中线粒体Ca 2+单向转运体（MCU）电流较低，表明线粒体Ca 2+摄取减少可能是由于（m）和MCU活性降低所致。与分离的心肌细胞相似，KO心脏的O-2消耗和ATP水平也降低。在模拟I/R模型下，KO心肌细胞中异常的线粒体生物能学加剧。与WT-I/R心脏切片相比，KO-I/R中的活性氧水平也显著更高，这与KO-I/R心脏中的线粒体功能障碍一致。我们的结论是TRPM 2通道通过改善线粒体功能障碍和降低活性氧水平来保护心脏免受I/R损伤。
Background: TRPM2 channels are present in the heart, but their function is unknown. Results: Genetic ablation of TRPM2 results in cardiac mitochondrial dysfunction, enhanced ROS production, and exacerbated cardiac ischemic injury. Conclusion: TRPM2 channels preserve cardiac mitochondrial bioenergetics and protect cardiac myocytes from ischemic injury. Significance: TRPM2 is a rational target for treatment of ischemic heart disease.Cardiac TRPM2 channels were activated by intracellular adenosine diphosphate-ribose and blocked by flufenamic acid. In adult cardiac myocytes the ratio of G(Ca) to G(Na) of TRPM2 channels was 0.56 +/- 0.02. To explore the cellular mechanisms by which TRPM2 channels protect against cardiac ischemia/reperfusion (I/R) injury, we analyzed proteomes from WT and TRPM2 KO hearts subjected to I/R. The canonical pathways that exhibited the largest difference between WT-I/R and KO-I/R hearts were mitochondrial dysfunction and the tricarboxylic acid cycle. Complexes I, III, and IV were down-regulated, whereas complexes II and V were up-regulated in KO-I/R compared with WT-I/R hearts. Western blots confirmed reduced expression of the Complex I subunit and other mitochondria-associated proteins in KO-I/R hearts. Bioenergetic analyses revealed that KO myocytes had a lower mitochondrial membrane potential, mitochondrial Ca2+ uptake, ATP levels, and O-2 consumption but higher mitochondrial superoxide levels. Additionally, mitochondrial Ca2+ uniporter (MCU) currents were lower in KO myocytes, indicating reduced mitochondrial Ca2+ uptake was likely due to both lower (m) and MCU activity. Similar to isolated myocytes, O-2 consumption and ATP levels were also reduced in KO hearts. Under a simulated I/R model, aberrant mitochondrial bioenergetics was exacerbated in KO myocytes. Reactive oxygen species levels were also significantly higher in KO-I/R compared with WT-I/R heart slices, consistent with mitochondrial dysfunction in KO-I/R hearts. We conclude that TRPM2 channels protect the heart from I/R injury by ameliorating mitochondrial dysfunction and reducing reactive oxygen species levels.