Cardiac Troponin I R193H Mutation Is Associated with Mitochondrial Damage in Cardiomyocytes
Cardiac Troponin I R193H Mutation Is Associated with Mitochondrial Damage in Cardiomyocytes
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DOI：
10.1089/dna.2020.5828
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发表时间：
2021-01-18
影响因子：
3.1
通讯作者：
Tian, Jie
中科院分区：
文献类型：
--
作者：
Luo, Jing;Zhao, Weian;Tian, Jie
心肌线粒体功能障碍在心血管疾病，特别是肥厚型和扩张型心肌病的发生发展中起着至关重要的作用。心肌肌钙蛋白I （cTnI）是一种重要的结构蛋白，对心肌细胞的收缩和舒张至关重要。最近的研究表明，突变的cTnIR193H可以作为其他细胞功能的调节分子。本研究旨在确定cTnI突变是否会导致心肌细胞线粒体功能障碍。用cTnIR193H腺病毒转染原代心肌细胞，空载体作为对照。转染72 h后，检测细胞线粒体结构和功能。透射电镜检查显示，R193H突变心肌细胞线粒体嵴断裂，空泡化，线粒体自噬。线粒体功能研究显示，与对照组相比，复合物I活性、ATP和活性氧水平以及耗氧量显著降低。Western blot分析显示，与对照组相比，R193H突变心肌细胞中线粒体相关基因ND5（泛醌氧化还原酶链5）、LRPPRC（富含亮氨酸的五肽重复家族蛋白）和PGC-1 α （PPARG共激活因子1 α）的表达显著下调。cTnIR193H突变转基因小鼠心肌细胞线粒体肿胀和嵴断裂，线粒体功能下降，而非同窝对照小鼠。本研究数据表明，cTnIR193H突变的心肌细胞线粒体结构和功能显著受损，提示cTnI可能在维持心肌线粒体结构和功能完整性方面起关键作用。
Malfunction of myocardial mitochondria plays a crucial role in the development of cardiovascular disorders, especially hypertrophic and dilated cardiomyopathies. Cardiac troponin I (cTnI) is an important structural protein and essential to contraction and relaxation of cardiomyocytes. Recent studies suggest that mutated cTnIR193H could function as a regulatory molecule for other cell functions. This study was to determine whether mutated cTnI could contribute to mitochondrial dysfunction of cardiomyocytes. Primary cardiomyocytes were transfected with cTnIR193H adenovirus with empty vector as control. Mitochondrial structure and function were evaluated in the cells 72 h after transfection. Transmission electron microscopy examination showed mitochondria in the cardiomyocytes with R193H mutation displayed broken cristae, vacuolation, and mitophagy. Mitochondrial function studies revealed a significant decrease in complex I activity, ATP and reactive oxygen species levels, and oxygen consumption rate compared with controls. Western blot analysis demonstrated that expressions of mitochondria-related genes, including ND5 (ubiquinone oxidoreductase chain 5), LRPPRC (a leucine-rich protein of pentatricopeptide repeat family), and PGC-1 alpha (PPARG co-activator 1 alpha), were significantly downregulated in R193H mutation cardiomyocytes compared with the control. Swelling and broken cristae were observed in the mitochondria of cardiomyocytes from cTnIR193H mutation transgenic mice with decreased mitochondrial function, not from the littermate control mice. The data from the present study demonstrated that mitochondrial structure and function were significantly impaired in cardiomyocytes with cTnIR193H mutation, suggesting that cTnI might be critically involved in maintaining the structural and functional integrity of myocardial mitochondria.