钙蛋白酶介导线粒体活性氧生成在心肌肥厚过程中的作用及机理

The involvement of calpain and mitochondrial reactive oxygen species (m-ROS) in the progression of pathophysiologies of cardiac hypertrophy has been recognised, however, the role and mechanisms of calpain mediating m-ROS generation in regulating cardiac hypertrophy has never been reported. Our preliminary data have shown that pressure overload induced the activation of calpain which correlated with the increase of m-ROS generation in heart.Furthermore, incubation with calpain repressed mitochondrial ATP synthase and induced m-ROS generation.Since m-ROS has been nicely shown to induce cardiac hypertrophy, we hypothesize that calpain mediates m-ROS generation contributing to the pathophysiological progress of cardiac hypertrophy. Accordingly, the present project is proposed to investigate the role of calpain in cardiac hypertrophy and to explore the underlying mechanisms. Specially, we will induce cardiac hypertrophy by pressure overload on cardiac specific calpain-4 knockout mice and study how calapin mediates m-ROS generation leading to cardiac hypertrophy.In cultured cardiomyocytes ,we will confirm the in vivo findings. The completion of present study will help understand the molecular mechanisms by which calpain mediates m-ROS generation and provide novel therapeutic targets for new drug design to treat the cardiac hypertrophy.

钙蛋白酶（Calpain）和线粒体活性氧（m-ROS）均参与心肌肥厚的病理生理过程，然而在心肌肥厚过程中关于二者之间调控关系的的机制研究却未见报道。我们的前期研究发现压力超负荷后心肌细胞内Calpain发生激活并且与m-ROS生成密切相关，Calpain与分离的线粒体共孵育能够抑制线粒体ATP合成酶的表达、促进m-ROS生成，据此推测调控m-ROS生成是Calpain参与心肌肥厚过程的主要机制之一。本课题拟利用心肌细胞特异性Calpain-4敲除小鼠构建压力超负荷型心肌肥厚模型，观察Calpain对m-ROS的调控作用，进一步在细胞水平揭示Calpain通过调节ATP合成酶进而干预m-ROS生成的分子机制。本课题通过阐明Calpain与m-ROS生成的关系，以拓展对心肌肥厚发生发展的分子调控机制的认识，为有效干预和治疗心肌肥厚的药物研发提供新的思路。

既往研究显示钙蛋白酶（Calpain）在心肌病理生理改变过程发挥重要的作用，然而在心肌肥厚过程中关于Calpain和线粒体活性氧（m-ROS）之间调控关系的的机制研究却未见报道。本课题利用心肌细胞特异性Calpain-4敲除小鼠构建压力超负荷型心肌肥厚模型，研究发现压力超负荷后心肌细胞内Calpain发生激活并且与ATP合成酶5A1及线粒体膜电位下调、m-ROS生成增加密切相关，而Calpain 4敲除能够抑制线粒体ATP合成酶5A1的降低、抑制m-ROS生成，据此推测调控m-ROS生成是Calpain参与心肌肥厚过程的主要机制之一。AngII诱导离体的对照组心肌细胞后，线粒体ATP合成酶5A1表达降低、m-ROS生成增加，而在Calpain-4敲除心肌细胞中线粒体内ROS生成受抑制、ATP 合成酶5A1表达下降较对照组改善，但是这种保护机制会被ATP合成酶抑制剂Oligomycin抵消。本课题利用心肌细胞特异性Calpain-4敲除小鼠构建心肌肥厚模型证实Calpain对m-ROS的调控，进一步在细胞水平揭示Calpain通过调节ATP合成酶进而干预m-ROS生成的分子机制。课题通过阐明Calpain与m-ROS生成的关系，以拓展对心肌肥厚发生发展的分子调控机制的认识，为有效干预和治疗心肌肥厚的药物研发提供新的思路。