Departments of Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA, 23298, USA.
Departments of Medicine (Division of Cardiology), Virginia Commonwealth University, Richmond, VA, 23298, USA.
Biochem Biophys Res Commun. 2022 Jul 12;613:127-132. doi: 10.1016/j.bbrc.2022.04.117. Epub 2022 Apr 29.
Activation of calpain1 (CPN1) contributes to mitochondrial dysfunction during cardiac ischemia (ISC) - reperfusion (REP). Blockade of electron transport using amobarbital (AMO) protects mitochondria during ISC-REP, indicating that the electron transport chain (ETC) is a key source of mitochondrial injury. We asked if AMO treatment can decrease CPN1 activation as a potential mechanism of mitochondrial protection during ISC-REP. Buffer-perfused adult rat hearts underwent 25 min global ISC and 30 min REP. AMO (2.5 mM) or vehicle was administered for 1 min before ISC to block electron flow in the ETC. Hearts in the time control group were untreated and buffer perfused without ISC. Hearts were collected at the end of perfusion and used for mitochondrial isolation. ISC-REP increased both the cleavage of spectrin (indicating cytosolic CPN1 activation) in cytosol and the truncation of AIF (apoptosis inducing factor, indicating mitochondrial CPN1 activation) in subsarcolemmal mitochondria compared to time control. Thus, ISC-REP activated both cytosolic and mitochondrial CPN1. AMO treatment prevented the cleavage of spectrin and AIF during ISC-REP, suggesting that the transient blockade of electron transport during ISC decreases CPN1 activation. AMO treatment decreased the activation of PARP [poly(ADP-ribose) polymerase] downstream of AIF that triggers caspase-independent apoptosis. AMO treatment also decreased the release of cytochrome c from mitochondria during ISC-REP that prevented caspase 3 activation. These results support that the damaged ETC activates CPN1 in cytosol and mitochondria during ISC-REP, likely via calcium overload and oxidative stress. Thus, AMO treatment to mitigate mitochondrial-driven cardiac injury can decrease both caspase-dependent and caspase-independent programmed cell death during ISC-REP.
钙蛋白酶 1（CPN1）的激活导致心脏缺血（ISC）-再灌注（REP）期间的线粒体功能障碍。使用阿米巴（AMO）阻断电子传递可在 ISC-REP 期间保护线粒体，这表明电子传递链（ETC）是线粒体损伤的关键来源。我们想知道 AMO 治疗是否可以减少 CPN1 激活，作为 ISC-REP 期间线粒体保护的潜在机制。缓冲液灌注的成年大鼠心脏经历 25 分钟的整体 ISC 和 30 分钟的 REP。在 ISC 前 1 分钟给予 AMO（2.5 mM）或载体以阻断 ETC 中的电子流。时间对照组的心脏未处理且未进行 ISC 缓冲液灌注。在灌注结束时收集心脏，并用于线粒体分离。与时间对照组相比，ISC-REP 增加了细胞质中血影蛋白的裂解（表明胞质 CPN1 激活）和亚肌节线粒体中 AIF（凋亡诱导因子，表明线粒体 CPN1 激活）的截断。因此，ISC-REP 激活了胞质和线粒体中的 CPN1。AMO 治疗可防止 ISC-REP 期间血影蛋白和 AIF 的裂解，表明 ISC 期间电子传递的短暂阻断可降低 CPN1 的激活。AMO 治疗降低了 AIF 下游 PARP [多聚（ADP-核糖）聚合酶]的激活，该酶触发 caspase 非依赖性细胞凋亡。AMO 治疗还减少了 ISC-REP 期间线粒体中细胞色素 c 的释放，从而阻止了 caspase 3 的激活。这些结果表明，在 ISC-REP 期间，受损的 ETC 通过钙超载和氧化应激在细胞质和线粒体中激活 CPN1。因此，AMO 治疗减轻线粒体驱动的心脏损伤可减少 ISC-REP 期间 caspase 依赖性和 caspase 非依赖性程序性细胞死亡。
