Inhibition of the ubiquitous calpains protects complex I activity and enables improved mitophagy in the heart following ischemia-reperfusion
Inhibition of the ubiquitous calpains protects complex I activity and enables improved mitophagy in the heart following ischemia-reperfusion
复制标题
DOI：
10.1152/ajpcell.00190.2019
复制
发表时间：
2019-11-01
影响因子：
5.5
通讯作者：
Lesnefsky, Edward J.
中科院分区：
文献类型：
--
作者：
Chen, Qun;Thompson, Jeremy;Lesnefsky, Edward J.
钙激活蛋白1(CPN1)和钙蛋白2(CPN2)参与心肌缺血(ISC)和再灌流(REP)时的损伤。ISC-rep后，心肌线粒体复合体I活性降低。CPN1和CPN2是广泛存在于细胞质(Cs)-CPN1和2以及线粒体(MIT)-CPN1和2中的钙蛋白酶。最近的研究表明，复合体I亚单位(NDUFS7)是MIT-CPN1的潜在底物。我们询问ISC-rep是否通过激活MIT-CPN1和-2而导致NDUFS7亚基的蛋白分解导致复杂I活性降低。Cs-CPN1和cs-2的激活减少了ISC-rep后肝细胞的有丝分裂。我们询问cs-CPN1和-2的激活是否损害了ISC-rep后心脏的有丝分裂吞噬。缓冲液灌流的大鼠心脏经历了25min的全局ISC和30min的Rep。用MDL-28170(MDL；10 mU M)抑制CPN1和-2。在心脏灌流结束时分离胞浆、肌膜下线粒体(SSM)和纤维间线粒体(IFM)。心肌ISC-rep导致SSM和IFM复合体I活性降低，NDUFS7含量减少。ISC-rep还导致细胞内Beclin-1含量减少，这是形成自噬小体所需的自噬途径的关键组成部分。MDL对缺血再灌流后心肌细胞内Beclin-1和线粒体NDUFS7的含量有保护作用。这些结果支持在心肌ISC-rep过程中，胞浆和线粒体钙蛋白酶的激活都会损害线粒体。线粒体定位的钙蛋白酶通过裂解关键亚单位来破坏复合体I。胞浆钙调蛋白的激活通过耗尽有丝分裂过程的一个关键成分而损害受损线粒体的移除，从而导致线粒体功能障碍。
Activation of calpain 1 (CPN1) and calpain 2 (CPN2) contributes to cardiac injury during ischemia (ISC) and reperfusion (REP). Complex I activity is decreased in heart mitochondria following ISC-REP. CPN1 and CPN2 are ubiquitous calpains that exist in both cytosol (cs)-CPN1 and 2 and mitochondria (mit)-CPN1 and 2. Recent work shows that the complex I subunit (NDUFS7) is a potential substrate of the mit-CPN1. We asked whether ISC-REP led to decreased complex I activity via proteolysis of the NDUFS7 subunit via activation of mit-CPN1 and -2. Activation of cs-CPN1 and -2 decreases mitophagy in hepatocytes following ISC-REP. We asked whether activation of cs-CPN1 and -2 impaired mitophagy in the heart following ISC-REP. Buffer-perfused rat hearts underwent 25 min of global ISC and 30 min of REP. MDL-28170 (MDL; 10 mu M) was used to inhibit CPN1 and -2. Cytosol, subsarcolemmal mitochondria (SSM), and interfibrillar mitochondria (IFM) were isolated at the end of heart perfusion. Cardiac ISC-REP led to decreased complex I activity with a decrease in the content of NDUFS7 in both SSM and IFM. ISC-REP also resulted in a decrease in cytosolic beclin-1 content, a key component of the autophagy pathway required to form autophagosomes. MDL treatment protected the contents of cytosolic beclin-1 and mitochondrial NDUFS7 in hearts following ISC-REP. These results support that activation of both cytosolic and mitochondrial calpains impairs mitochondria during cardiac ISC-REP. Mitochondria-localized calpains impair complex I via cleavage of a key subunit. Activation of cytosolic calpains contributes to mitochondrial dysfunction by impairing removal of the impaired mitochondria through depletion of a key component of the mitophagy process.