Lim Soyeon, Chang Woochul, Cha Min-Ji, Song Byeong-Wook, Ham Onju, Lee Se-Yeon, Lee Changyoun, Park Jun-Hee, Lee Sang-Kyou, Jang Yangsoo, Hwang Ki-Chul
Severance Integrative Research Institute for Cerebral & Cardiovascular Disease, Yonsei University Health System, Seoul, Republic of Korea.
Department of Biology Education, College of Education, Pusan National University, Busan, Republic of Korea.
Mol Ther. 2014 Jun;22(6):1110-1121. doi: 10.1038/mt.2014.46. Epub 2014 Mar 18.
Myocardial Ca(2+) overload induced by ischemia/reperfusion (I/R) is a major element of myocardial dysfunction in heart failure. Phospholipase C (PLC) plays important roles in the regulation of the phosphoinositol pathway and Ca(2+) homeostasis in various types of cells. Here, we investigated the protective role of PLCδ1 against myocardial I/R injury through the regulation of Ca(2+) homeostasis. To investigate its role, PLCδ1 was fused to Hph1, a cell-permeable protein transduction domain (PTD), and treated into rat neonatal cardiomyocytes and rat hearts under respective hypoxia-reoxygenation (H/R) and ischemia-reperfusion conditions. Treatment with Hph1-PLCδ1 significantly inhibited intracellular Ca(2+) overload, reactive oxygen species generation, mitochondrial permeability transition pore opening, and mitochondrial membrane potential elevation in H/R neonatal cardiomyocytes, resulting in the inhibition of apoptosis. Intravenous injections of Hph1-PLCδ1 in rats with I/R-injured myocardium caused significant reductions in infarct size and apoptosis and also improved systolic and diastolic cardiac functioning. Furthermore, a small ions profile obtained using time-of-flight secondary ion mass spectrometry showed that treatment with Hph1-PLCδ1 leads to significant recovery of calcium-related ions toward normal levels in I/R-injured myocardium. These results suggest that Hph1-PLCδ1 may manifest as a promising cardioprotective drug due to its inhibition of the mitochondrial apoptotic pathway in cells suffering from I/R injury.
缺血/再灌注（I/R）诱导的心肌Ca(2+)超载是心力衰竭中心肌功能障碍的主要因素。磷脂酶C（PLC）在多种细胞类型的磷酸肌醇途径调节和Ca(2+)稳态中发挥重要作用。在此，我们通过调节Ca(2+)稳态研究了PLCδ1对心肌I/R损伤的保护作用。为研究其作用，将PLCδ1与细胞穿透蛋白转导结构域（PTD）Hph1融合，并在各自的缺氧-复氧（H/R）和缺血-再灌注条件下处理大鼠新生心肌细胞和大鼠心脏。用Hph1-PLCδ1处理可显著抑制H/R新生心肌细胞内的Ca(2+)超载、活性氧生成、线粒体通透性转换孔开放和线粒体膜电位升高，从而抑制细胞凋亡。对I/R损伤心肌的大鼠静脉注射Hph1-PLCδ1可显著减小梗死面积和细胞凋亡，并改善心脏的收缩和舒张功能。此外，使用飞行时间二次离子质谱获得的小离子图谱显示，用Hph1-PLCδ1处理可使I/R损伤心肌中钙相关离子显著恢复至正常水平。这些结果表明，Hph1-PLCδ1可能因其抑制I/R损伤细胞中的线粒体凋亡途径而成为一种有前景的心脏保护药物。
