TNFα-induced cytoprotection requires the production of free radicals within mitochondria in C2C12 myotubes
TNFα-induced cytoprotection requires the production of free radicals within mitochondria in C2C12 myotubes
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DOI：
10.1016/j.lfs.2006.07.020
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发表时间：
2006-11-02
期刊：
影响因子：
6.1
通讯作者：
Lecour, Sandrine
中科院分区：
文献类型：
--
作者：
Lacerda, Lydia;Smith, Robert M.;Lecour, Sandrine
我们以前报道，肿瘤坏死因子α（TNF α）可以模拟经典的缺血预处理（IPC）在细胞和心脏。然而，所涉及的信号通路仍然不完全清楚。一种潜在的保护途径可能是TNF α诱导的活性氧（ROS）。我们假设TNF α的细胞保护作用是通过产生线粒体内的ROS而发生的。C2 C12肌管在模拟缺血损伤之前用短时间缺氧（IPC）或低浓度TNF α（0.5ng/ml）预处理。通过流式细胞术在用二氯荧光素二乙酸酯（DCFH-DA）染色的细胞上评估ROS产生。用Mitotracker Red CM-H（2）XRos检查TNF α诱导的ROS来源。通过研究呼吸参数和线粒体内膜电位来评价线粒体的生物能量学。与模拟缺血对照相比，用TNF α预处理改善了细胞活力（TNF α：75 +/-1%对比对照的34.1%：p < 0.001）。ROS清除剂N-2-巯基丙酰-甘氨酸（MPG）将TNF α刺激的细胞的存活率降低至151%（p < 0.001，相对于TNF α）。用IPC获得了类似的结果。TNF α刺激主要在线粒体中增加ROS产生，并且这种增加在MPG存在下被消除。向细胞中加入TNF α增加了状态2呼吸，并在缺血性损伤之前适度地使膜电位去极化。总之，TNF α诱导的ROS产生可发生在线粒体内，导致线粒体暂时扰动，这可能启动TNF α的细胞保护作用。(c)2006年爱思唯尔公司All rights reserved.
We previously reported that tumour necrosis factor alpha (TNF alpha) can mimic classic ischemic preconditioning (IPC) in both cells and heart. However, the signalling pathways involved remain incompletely understood. One potential protective pathway could be TNF alpha-induced reactive oxygen species (ROS). We hypothesized that TNF alpha cytoprotection occurs through the generation of ROS which originate within the mitochondria. C2C12 myotubes were preconditioned with either a short period of hypoxia (IPC) or a low concentration of TNF alpha (0.5 ng/ml) prior to a simulated ischemic insult. ROS generation was evaluated on cells stained with dichlorofluorescin diacetate (DCFH-DA) by flow cytometry. The source of TNF alpha-induced ROS was examined with Mitotracker Red CM-H(2)XRos. The bioenergetics of the mitochondria were evaluated by investigation of the respiratory parameters and the inner mitochondrial membrane potential. Pretreatment with TNFa improved cell viability compared with the simulated ischemic control (TNFa: 75 +/- 1% versus 34 1% for the control: p < 0.001). The ROS scavenger, N-2-mercaptopropionyl-glycine (MPG), reduced the viability of TNF alpha-stimulated cells to 15 1% (p < 0.001 versus TNF alpha). Similar results were obtained with IPC. TNFa stimulation increased ROS production mainly in the mitochondria, and this increase was abolished in the presence of MPG. Addition of TNF alpha to the cells increased State 2 respiration and modestly depolarised the membrane potential prior to the ischemic insult. In conclusion, TNF alpha-induced ROS generation can occur within the mitochondria, resulting in temporal mitochondrial perturbations which may initiate the cytoprotective effect of TNF alpha. (c) 2006 Elsevier Inc. All rights reserved.