Department of Cardiology, Shanghai University of Medicine & Health Sciences Affiliated Zhoupu Hospital, Shanghai, China,
School of Basic Medical Sciences and Shanghai Key Laboratory of Molecular Imaging, Shanghai University of Medicine & Health Sciences, Shanghai, China,
Pharmacology. 2021;106(5-6):275-285. doi: 10.1159/000511961. Epub 2020 Dec 10.
Moderate hydrogen peroxide postconditioning (H2O2PoC) activates signal transducer and activator of transcription 3 (STAT3) to alleviate mitochondrial calcium overload during cardiac ischemia/reperfusion (I/R). However, the initial time window of STAT3-induced calcium hemostasis, the production of reactive oxygen species (ROS) and adenosine triphosphate (ATP) in H2O2PoC, and its regulated mechanism remain unknown. This study aimed to investigate H2O2PoC-induced homeostasis of calcium, ROS and ATP, and the role of STAT3 in the regulation.
Isolated rat cardiomyocytes were exposed to H2O2PoC and Janus kinase 2 (JAK2)/STAT3 inhibitor AG490 during I/R. Ca2+ transients, cell contraction, intracellular calcium concentration, ROS production, ATP contents, phosphorylation of STAT3, gene and protein expression of manganese superoxide dismutase (MnSOD), metallothionein 1 (MT1) and metallothionein 2 (MT2), as well as activities of mitochondrial complex I and complex II were detected.
Moderate H2O2PoC improved post-ischemic Ca2+ transients and cell contraction recovery as well as alleviated cytosolic and mitochondrial calcium overload, which were abrogated by AG490 in rat cardiomyocytes. Moderate H2O2PoC increased ROS production and rate of ROS production at early reperfusion in rat I/R cardiomyocytes, and this phenomenon was also abrogated by AG490. Notably, the expression of phosphorylated nuclear STAT3; gene and protein expression of MnSOD, MT1, and MT2; and activities of mitochondrial complex I and complex II were upregulated by moderate H2O2PoC but downregulated by AG490.
These findings indicated that the cardioprotection of moderate H2O2PoC against cardiac I/R could be associated with activated STAT3 at early reperfusion to maintain calcium, ROS, and ATP homeostasis in rat cardiomyocytes.
适度过氧化氢后处理（H2O2PoC）通过激活信号转导和转录激活因子 3（STAT3）减轻心脏缺血/再灌注（I/R）期间的线粒体钙超载。然而，在 H2O2PoC 中，STAT3 诱导钙稳态、活性氧（ROS）和三磷酸腺苷（ATP）产生的起始时间窗口及其调控机制尚不清楚。本研究旨在探讨 H2O2PoC 诱导的钙、ROS 和 ATP 稳态以及 STAT3 在调节中的作用。
在 I/R 期间，将分离的大鼠心肌细胞暴露于 H2O2PoC 和 Janus 激酶 2（JAK2）/STAT3 抑制剂 AG490。检测 Ca2+ 瞬变、细胞收缩、细胞内钙浓度、ROS 产生、ATP 含量、STAT3 磷酸化、锰超氧化物歧化酶（MnSOD）、金属硫蛋白 1（MT1）和金属硫蛋白 2（MT2）的基因和蛋白表达，以及线粒体复合物 I 和复合物 II 的活性。
适度 H2O2PoC 改善了缺血后 Ca2+ 瞬变和细胞收缩恢复，减轻了细胞质和线粒体钙超载，而 AG490 在大鼠心肌细胞中则消除了这些作用。适度 H2O2PoC 增加了大鼠 I/R 心肌细胞再灌注早期的 ROS 产生和 ROS 产生速率，而 AG490 也消除了这一现象。值得注意的是，适度 H2O2PoC 上调了磷酸化核 STAT3 的表达、MnSOD、MT1 和 MT2 的基因和蛋白表达，以及线粒体复合物 I 和复合物 II 的活性，而 AG490 则下调了这些表达。
这些发现表明，适度 H2O2PoC 对心脏 I/R 的保护作用可能与再灌注早期激活 STAT3 有关，以维持大鼠心肌细胞中的钙、ROS 和 ATP 稳态。
