Deletion of capn4 Protects the Heart Against Endotoxemic Injury by Preventing ATP Synthase Disruption and Inhibiting Mitochondrial Superoxide Generation.
Deletion of capn4 Protects the Heart Against Endotoxemic Injury by Preventing ATP Synthase Disruption and Inhibiting Mitochondrial Superoxide Generation.
复制标题
capn4 的缺失可通过防止 ATP 合酶破坏和抑制线粒体超氧化物生成来保护心脏免受内毒素损伤。
DOI：
10.1161/circheartfailure.115.002383
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发表时间：
2015-09
期刊：
影响因子：
--
通讯作者：
Peng T
中科院分区：
文献类型：
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作者：
Ni R;Zheng D;Wang Q;Yu Y;Chen R;Sun T;Wang W;Fan GC;Greer PA;Gardiner RB;Peng T
我们最近的研究表明，通过转基因过表达钙pastatin来抑制calpain可以减少内毒素血症中心肌的促炎反应和功能障碍。然而，潜在的机制仍有待确定。在这项研究中，我们使用心肌细胞特异性capn4敲除小鼠来研究内毒素血症中calpain是否以及如何破坏ATP合酶并诱导线粒体超氧化物的产生。给心肌细胞特异性capn4基因敲除小鼠及其野生型幼崽注射脂多糖（LPS）。4小时后，内毒素小鼠心脏线粒体calpain-1蛋白及活性升高。线粒体calpain-1与ATP合成酶-α (ATP5A1)共定位并切割，导致ATP合成酶被破坏，同时在LPS刺激下线粒体活性氧（ROS）的产生增加。在内毒素小鼠中，缺失capn4或上调ATP5A1可增加ATP合成酶活性，阻止线粒体ROS生成，减少促炎反应和心肌功能障碍。在培养的心肌细胞中，LPS诱导线粒体产生超氧化物，这可以通过线粒体靶向calpastatin或ATP5A1的过表达来阻止。线粒体中calpain-1的上调充分诱导了超氧化物的产生和促炎反应，这两种反应都被ATP5A1过表达或线粒体靶向超氧化物歧化酶模拟物mito-TEMPO减弱。内毒素小鼠心肌细胞特异性capn4敲除可保护心脏免受lps诱导的损伤。LPS诱导线粒体中calpain-1的积累。线粒体calpain-1破坏ATP合成酶，导致线粒体ROS生成，从而促进内毒素血症时的促炎反应和心肌功能障碍。这些发现揭示了钙蛋白酶介导败血症心肌功能障碍的新机制。
Our recent study has demonstrated that inhibition of calpain by transgenic over-expression of calpastatin reduces myocardial pro-inflammatory response and dysfunction in endotoxemia. However, the underlying mechanisms remain to be determined. In this study, we employed cardiomyocyte-specific capn4 knockout mice to investigate whether and how calpain disrupts ATP synthase and induces mitochondrial superoxide generation during endotoxemia. Cardiomyocyte-specific capn4 knockout mice and their wild-type littermates were injected with lipopolysaccharides (LPS). Four hours later, calpain-1 protein and activity were increased in mitochondria of endotoxemic mouse hearts. Mitochondrial calpain-1 co-localized with and cleaved ATP synthase-α (ATP5A1), leading to ATP synthase disruption and a concomitant increase in mitochondrial reactive oxygen species (ROS) generation during LPS stimulation. Deletion of capn4 or up-regulation of ATP5A1 increased ATP synthase activity, prevented mitochondrial ROS generation, and reduced pro-inflammatory response and myocardial dysfunction in endotoxemic mice. In cultured cardiomyocytes, LPS induced mitochondrial superoxide generation which was prevented by over-expression of mitochondria-targeted calpastatin or ATP5A1. Up-regulation of calpain-1 specifically in mitochondria sufficiently induced superoxide generation and pro-inflammatory response, both of which were attenuated by ATP5A1 over-expression or mitochondria-targeted superoxide dismutase mimetics, mito-TEMPO. Cardiomyocyte-specific capn4 knockout protects the heart against LPS-induced injury in endotoxemic mice. LPS induces calpain-1 accumulation in mitochondria. Mitochondrial calpain-1 disrupts ATP synthase, leading to mitochondrial ROS generation, which promotes pro-inflammatory response and myocardial dysfunction during endotoxemia. These findings uncover a novel mechanism by which calpain mediates myocardial dysfunction in sepsis.