Cytoprotective Role of Nrf2 in Electrical Pulse Stimulated C2C12 Myotube.
Cytoprotective Role of Nrf2 in Electrical Pulse Stimulated C2C12 Myotube.
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DOI：
10.1371/journal.pone.0144835
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Shoda J
中科院分区：
文献类型：
--
作者：
Horie M;Warabi E;Komine S;Oh S;Shoda J
定期体育锻炼是健康生活方式的核心。然而，运动相关的肌肉收缩可以诱导骨骼肌中活性氧和活性氮（ROS/RNS）的产生。核因子E2相关因子2（Nrf 2）转录因子是氧化应激的细胞传感器。核Nrf 2信号调节抗氧化反应，保护器官结构和功能。然而，Nrf 2在运动或收缩诱导的骨骼肌ROS/RNS产生中的作用尚不清楚。在这项研究中，使用分化的C2 C12细胞和肌肉收缩的电脉冲刺激（EPS），我们探讨是否Nrf 2在骨骼肌对肌肉收缩诱导的ROS/RNS的反应中发挥作用。我们发现，EPS（40 V，1 Hz，2 ms）刺激ROS/RNS积累和Nrf 2激活。我们还发现，NQO 1，HO-1和GCLM的表达增加后，EPS诱导的肌肉收缩和显着抑制与Nrf 2敲低的细胞。我们还发现，抗氧化剂N-乙酰半胱氨酸（NAC）显着减弱Nrf 2激活后EPS，而一氧化氮合成酶抑制剂Nω-硝基-L-精氨酸甲酯（L-NAME）没有。此外，Nrf 2敲低后EPS显着降低ROS/RNS氧化还原电位和细胞活力，并增加C2 C12肌管中的凋亡标志物膜联蛋白V的表达。这些结果表明，Nrf 2激活和Nrf 2调节基因的表达保护肌肉免受由EPS诱导的肌肉收缩引起的ROS增加。因此，我们的研究结果表明，Nrf 2可能是肌肉收缩过程中保存肌肉功能的关键因素。
Regular physical exercise is central to a healthy lifestyle. However, exercise-related muscle contraction can induce reactive oxygen species and reactive nitrogen species (ROS/RNS) production in skeletal muscle. The nuclear factor-E2-related factor-2 (Nrf2) transcription factor is a cellular sensor for oxidative stress. Regulation of nuclear Nrf2 signaling regulates antioxidant responses and protects organ structure and function. However, the role of Nrf2 in exercise- or contraction-induced ROS/RNS production in skeletal muscle is not clear. In this study, using differentiated C2C12 cells and electrical pulse stimulation (EPS) of muscle contraction, we explored whether Nrf2 plays a role in the skeletal muscle response to muscle contraction-induced ROS/RNS. We found that EPS (40 V, 1 Hz, 2 ms) stimulated ROS/RNS accumulation and Nrf2 activation. We also showed that expression of NQO1, HO-1 and GCLM increased after EPS-induced muscle contraction and was remarkably suppressed in cells with Nrf2 knockdown. We also found that the antioxidant N-acetylcysteine (NAC) significantly attenuated Nrf2 activation after EPS, whereas the nitric oxide synthetase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME) did not. Furthermore, Nrf2 knockdown after EPS markedly decreased ROS/RNS redox potential and cell viability and increased expression of the apoptosis marker Annexin V in C2C12 myotubes. These results indicate that Nrf2 activation and expression of Nrf2 regulated-genes protected muscle against the increased ROS caused by EPS-induced muscle contraction. Thus, our findings suggest that Nrf2 may be a key factor for preservation of muscle function during muscle contraction.