钙调神经磷酸酶1-1L调节剂通过线粒体自噬保护心肌细胞免受缺氧诱导的凋亡。

Regulator of calcineurin 1-1L protects cardiomyocytes against hypoxia-induced apoptosis via mitophagy.

作者信息

Yan Lijie, Yang Haitao, Li Yongqiang, Duan Hongyan, Wu Jintao, Qian Peng, Li Bing, Wang Shanling

机构信息

Department of Cardiology, Henan Provincial People's Hospital, Zhengzhou, China.

出版信息

J Cardiovasc Pharmacol. 2014 Oct;64(4):310-7. doi: 10.1097/FJC.0000000000000121.

Abstract

Mitochondrial dysfunction induced by myocardial ischemia is the primary cause of cardiac cell death. Specific removal of damaged mitochondria through mitophagy may be beneficial for cardiomyocyte protection against ischemia. Regulator of calcineurin 1-1L (Rcan1-1L) has been implicated in mitophagy induction in neurons. However, whether or not Rcan1-1L can evoke mitophagy in cardiomyocytes during hypoxia remains unknown. This study aims to investigate the effect of Rcan1-1L overexpression on cardiomyocytes during hypoxia and the possible underlying mechanism. The results of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that Rcan1-1L overexpression inhibited cell growth under normoxic conditions, whereas Rcan1-1L overexpression significantly reversed the growth inhibition induced by hypoxia. The results of terminal deoxynucleotidyl transferase biotin-dUTP nick end-labeling assay showed that cell apoptosis induced by hypoxia was markedly reduced by Rcan1-1L overexpression. In addition, Rcan1-1L overexpression inhibited the expression of the proapoptotic protein Bcl-2-associated death promoter and increased that of the antiapoptotic protein Bcl-2. Rcan1-1L overexpression opened the mitochondrial permeability transition pore and decreased mitochondrial mass. Meanwhile, the release of reactive oxygen species from mitochondria was suppressed by Rcan1-1L. Autophagy flow activation represented by mammalian target of rapamycin inhibition and microtubule-associated protein light chain 3 (LC3) upregulation was also demonstrated. Compared with endoplasmic reticulum and Golgi apparatus protein markers, the mitochondrial protein marker translocase of outer mitochondrial membranes 20 (TOM20) was downregulated by Rcan1-1L overexpression. Moreover, Rcan1-1L increased mitophagy receptor Parkin translocation into mitochondria from cytosol. Additionally, the effect of Rcan1-1L on cell growth, cell apoptosis and mitochondria mass was blocked by Parkin expression silencing. Overall, these data suggest that Rcan1-1L protects cardiomyocytes from hypoxia-induced apoptosis by inducing mitophagy partly through Parkin. This study provided novel insights into the prevention and treatment of ischemic heart disease.

摘要

心肌缺血诱导的线粒体功能障碍是心脏细胞死亡的主要原因。通过线粒体自噬特异性清除受损线粒体可能有利于保护心肌细胞免受缺血损伤。钙调神经磷酸酶1-1L(Rcan1-1L)已被证明与神经元中线粒体自噬的诱导有关。然而,Rcan1-1L在缺氧期间是否能在心肌细胞中引发线粒体自噬仍不清楚。本研究旨在探讨缺氧期间Rcan1-1L过表达对心肌细胞的影响及其潜在机制。3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐(MTT)检测结果显示,Rcan1-1L过表达在常氧条件下抑制细胞生长,而Rcan1-1L过表达显著逆转缺氧诱导的生长抑制。末端脱氧核苷酸转移酶生物素-dUTP缺口末端标记检测结果显示,Rcan1-1L过表达显著降低缺氧诱导的细胞凋亡。此外,Rcan1-1L过表达抑制促凋亡蛋白Bcl-2相关死亡促进因子的表达,并增加抗凋亡蛋白Bcl-2的表达。Rcan1-1L过表达开放线粒体通透性转换孔并减少线粒体质量。同时,Rcan1-1L抑制线粒体活性氧的释放。还证明了以雷帕霉素哺乳动物靶点抑制和微管相关蛋白轻链3(LC3)上调为代表的自噬流激活。与内质网和高尔基体蛋白标志物相比,线粒体外膜转位酶20(TOM20)这一线粒体蛋白标志物被Rcan1-1L过表达下调。此外,Rcan1-1L增加线粒体自噬受体Parkin从胞质溶胶向线粒体的转位。另外,Parkin表达沉默阻断了Rcan1-1L对细胞生长、细胞凋亡和线粒体质量的影响。总体而言,这些数据表明Rcan1-1L通过部分经由Parkin诱导线粒体自噬来保护心肌细胞免受缺氧诱导的凋亡。本研究为缺血性心脏病的防治提供了新的见解。

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