TBC1D15/RAB7-regulated mitochondria-lysosome interaction confers cardioprotection against acute myocardial infarction-induced cardiac injury.
TBC1D15/RAB7-regulated mitochondria-lysosome interaction confers cardioprotection against acute myocardial infarction-induced cardiac injury.
复制标题
TBC1D15/RAB7调节的线粒体溶酶体生理和病理生理学意义心肌梗死引起的心脏损伤
DOI：
10.7150/thno.46883
复制
发表时间：
2020
期刊：
影响因子：
12.4
通讯作者：
Zhang Y
中科院分区：
文献类型：
--
作者：
Yu W;Sun S;Xu H;Li C;Ren J;Zhang Y
原理：缺血性心脏病仍然是人类健康的主要威胁，但其确切的发病机制仍不清楚。TBC结构域家族成员15（TBC 1D 15）是参与线粒体动力学调节的RAB 7 GTP酶激活蛋白。本研究旨在探讨TBC 1D 15在急性心肌梗死（MI）心肌损伤中的作用及其可能机制。方法：采用透射电镜和活细胞延时成像技术评价线粒体-溶酶体相互作用。通过荧光和蛋白质印迹法测量线粒体自噬通量。在3天MI程序之前，通过心肌内注射用腺病毒TBC 1D 15转染成年小鼠。从整体心脏、心肌细胞、细胞器和细胞信号转导水平评价心脏形态和功能。结果如下：结果显示心肌梗死后3 d TBC 1D 15表达下调，心肌收缩功能下降，梗死面积和心肌间质纤维化明显，心肌细胞凋亡和线粒体损伤增加。TBC 1D 15的过表达恢复心脏收缩功能，减轻梗死面积和心肌间质纤维化，减少心肌细胞凋亡和线粒体损伤，尽管TBC 1D 15本身在没有MI的情况下没有发挥任何心肌作用。进一步的研究表明，3天MI诱导的受损线粒体的积累与线粒体清除的阻断有关，这是由于扩大的缺陷溶酶体和随后中断的线粒体自噬通量，这被TBC 1D 15过表达减弱。机制研究表明，3天MI引起异常的线粒体-溶酶体接触，导致溶酶体扩大，随后使受损线粒体的溶酶体清除功能丧失。TBC 1D 15通过TBC 1D 15的Fis 1结合和RAB 7 GAP酶激活结构域松开了异常的溶酶体-溶酶体接触，因为TBC 1D 15依赖性有益反应通过在体外和体内干扰这两个结构域中的任一个而逆转。结论：我们的研究结果表明，TBC 1D 15通过Fis 1/RAB 7调节的线粒体-溶酶体接触和随后的溶酶体依赖性线粒体自噬通量激活在急性MI诱导的心脏异常中起关键作用，这可能为急性MI的临床治疗提供新的靶点。
Rationale: Ischemic heart disease remains a primary threat to human health, while its precise etiopathogenesis is still unclear. TBC domain family member 15 (TBC1D15) is a RAB7 GTPase-activating protein participating in the regulation of mitochondrial dynamics. This study was designed to explore the role of TBC1D15 in acute myocardial infarction (MI)-induced cardiac injury and the possible mechanism(s) involved. Methods: Mitochondria-lysosome interaction was evaluated using transmission electron microscopy and live cell time-lapse imaging. Mitophagy flux was measured by fluorescence and western blotting. Adult mice were transfected with adenoviral TBC1D15 through intra-myocardium injection prior to a 3-day MI procedure. Cardiac morphology and function were evaluated at the levels of whole-heart, cardiomyocytes, intracellular organelles and cell signaling transduction. Results: Our results revealed downregulated level of TBC1D15, reduced systolic function, overt infarct area and myocardial interstitial fibrosis, elevated cardiomyocyte apoptosis and mitochondrial damage 3 days after MI. Overexpression of TBC1D15 restored cardiac systolic function, alleviated infarct area and myocardial interstitial fibrosis, reduced cardiomyocyte apoptosis and mitochondrial damage although TBC1D15 itself did not exert any myocardial effect in the absence of MI. Further examination revealed that 3-day MI-induced accumulation of damaged mitochondria was associated with blockade of mitochondrial clearance because of enlarged defective lysosomes and subsequent interrupted mitophagy flux, which were attenuated by TBC1D15 overexpression. Mechanistic studies showed that 3-day MI provoked abnormal mitochondria-lysosome contacts, leading to lysosomal enlargement and subsequently disabled lysosomal clearance of damaged mitochondria. TBC1D15 loosened the abnormal mitochondria-lysosome contacts through both the Fis1 binding and the RAB7 GAPase-activating domain of TBC1D15, as TBC1D15-dependent beneficial responses were reversed by interference with either of these two domains both in vitro and in vivo. Conclusions: Our findings indicated a pivotal role of TBC1D15 in acute MI-induced cardiac anomalies through Fis1/RAB7 regulated mitochondria-lysosome contacts and subsequent lysosome-dependent mitophagy flux activation, which may provide a new target in the clinical treatment of acute MI.