LAPEC EA-4278, Avignon Université, 84000, Avignon, France.
Université Paris-Saclay, CEA, INRAE, Département Médicaments et Technologies pour la Santé (DMTS), SPI, 30200, Bagnols-sur-Cèze, France.
Basic Res Cardiol. 2021 Dec 23;116(1):66. doi: 10.1007/s00395-021-00906-3.
Endothelial nitric oxide synthase (eNOS) activation in the heart plays a key role in exercise-induced cardioprotection during ischemia-reperfusion, but the underlying mechanisms remain unknown. We hypothesized that the cardioprotective effect of exercise training could be explained by the re-localization of eNOS-dependent nitric oxide (NO)/S-nitrosylation signaling to mitochondria. By comparing exercised (5 days/week for 5 weeks) and sedentary Wistar rats, we found that exercise training increased eNOS level and activation by phosphorylation (at serine 1177) in mitochondria, but not in the cytosolic subfraction of cardiomyocytes. Using confocal microscopy, we confirmed that NO production in mitochondria was increased in response to HO exposure in cardiomyocytes from exercised but not sedentary rats. Moreover, by S-nitrosoproteomic analysis, we identified several key S-nitrosylated proteins involved in mitochondrial function and cardioprotection. In agreement, we also observed that the increase in Ca retention capacity by mitochondria isolated from the heart of exercised rats was abolished by exposure to the NOS inhibitor L-NAME or to the reducing agent ascorbate, known to denitrosylate proteins. Pre-incubation with ascorbate or L-NAME also increased mitochondrial reactive oxygen species production in cardiomyocytes from exercised but not from sedentary animals. We confirmed these results using isolated hearts perfused with L-NAME before ischemia-reperfusion. Altogether, these results strongly support the hypothesis that exercise training increases eNOS/NO/S-nitrosylation signaling in mitochondria, which might represent a key mechanism of exercise-induced cardioprotection.
心脏内皮型一氧化氮合酶（eNOS）的激活在缺血再灌注引起的运动性心脏保护中起着关键作用，但潜在机制尚不清楚。我们假设，运动训练的心脏保护作用可以通过 eNOS 依赖的一氧化氮（NO）/S-亚硝化信号向线粒体的重新定位来解释。通过比较运动（每周 5 天，持续 5 周）和久坐的 Wistar 大鼠，我们发现运动训练增加了线粒体中 eNOS 的水平和磷酸化（丝氨酸 1177 位）激活，但在心肌细胞的胞质亚部分没有增加。通过共聚焦显微镜，我们证实，在心肌细胞中暴露于 HO 后，线粒体中 NO 的产生在运动大鼠中增加，但在久坐大鼠中没有增加。此外，通过 S-亚硝基蛋白组学分析，我们鉴定了几种涉及线粒体功能和心脏保护的关键 S-亚硝基化蛋白。一致地，我们还观察到，来自运动大鼠心脏的线粒体的 Ca 保留能力的增加，在暴露于 NOS 抑制剂 L-NAME 或已知的蛋白去亚硝基化还原剂抗坏血酸后被消除。在来自运动动物的心肌细胞中，抗坏血酸或 L-NAME 的预孵育也增加了线粒体活性氧的产生。我们使用在缺血再灌注前用 L-NAME 灌注的分离心脏证实了这些结果。总之，这些结果强烈支持运动训练增加线粒体中 eNOS/NO/S-亚硝化信号的假设，这可能是运动诱导的心脏保护的关键机制。
