The Heart Center, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China.
National Clinical Research Center of Cardiovascular Diseases, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100037, China.
J Mol Med (Berl). 2018 Jul;96(7):611-620. doi: 10.1007/s00109-018-1649-2. Epub 2018 May 14.
The cystic fibrosis transmembrane conductance regulator (CFTR) is linked to cell apoptosis and abundantly expressed in brain tissue. Mitochondrial oxidative stress plays a key role in activating apoptotic pathway following cerebral ischemia reperfusion (IR) injury. Reduced glutathione (GSH) is exclusively synthesized in cytosol but distributed in mitochondria. In the present study, we investigated whether CFTR affected mitochondrial oxidative stress via regulating GSH and thereby protected neurons against apoptosis following cerebral IR. Brains were subjected to global IR by four-vessel occlusion and CFTR activator forskolin (FSK) was used in vivo. CFTR silence was performed in vitro for neurons by RNA interference. We found that FSK suppressed neuronal apoptosis whereas CFTR silence enhanced neuronal apoptosis. FSK prevented the elevations in reactive oxygen species (ROS) and caspase activities while FSK inhibited the reductions in complex I activity and mitochondrial GSH level following IR. FSK decreased mitochondrial oxidative stress partially and preserved mitochondrial function. On the contrary, CFTR silence exaggerated mitochondrial dysfunction. CFTR loss increased hydrogen peroxide (HO) level and decreased GSH level in mitochondria. Importantly, we showed that CFTR was located on mitochondrial membrane. GSH transport assay suggested that GSH decrease may be a consequence not a reason for mitochondrial oxidative stress mediated by CFTR disruption. Our results highlight the central role of CFTR in the pathogenesis of cerebral IR injury. CFTR regulates neuronal apoptosis following cerebral IR via mitochondrial oxidative stress-dependent pathway. The mechanism of CFTR-mediated mitochondrial oxidative stress needs further studies. KEY MESSAGES: CFTR activation protects brain tissue against IR-induced apoptosis and oxidative stress. CFTR disruption enhances HO-induced neuronal apoptosis and CFTR loss leads to mitochondrial oxidative stress. CFTR regulates IR-induced neuronal apoptosis via mitochondrial oxidative stress. CFTR may be a potential therapeutic target to cerebral IR damage.
囊性纤维化跨膜电导调节因子（CFTR）与细胞凋亡有关，在脑组织中大量表达。线粒体氧化应激在脑缺血再灌注（IR）损伤后激活凋亡途径中起关键作用。还原型谷胱甘肽（GSH）仅在细胞质中合成，但分布在线粒体中。本研究旨在探讨 CFTR 是否通过调节 GSH 影响线粒体氧化应激，从而防止脑 IR 后神经元凋亡。通过四血管闭塞使大脑发生全局 IR，并在体内使用 CFTR 激活剂福司柯林（FSK）。通过 RNA 干扰在体外对神经元进行 CFTR 沉默。我们发现 FSK 抑制神经元凋亡，而 CFTR 沉默增强神经元凋亡。FSK 可防止 IR 后活性氧（ROS）和半胱天冬酶活性的升高，同时抑制复合物 I 活性和线粒体 GSH 水平的降低。FSK 部分减轻了线粒体氧化应激并维持了线粒体功能。相反，CFTR 沉默加剧了线粒体功能障碍。CFTR 缺失增加了线粒体中的过氧化氢（HO）水平并降低了 GSH 水平。重要的是，我们表明 CFTR 位于线粒体膜上。GSH 转运测定表明，CFTR 破坏导致的线粒体氧化应激增加可能是 GSH 减少的结果，而不是原因。我们的研究结果强调了 CFTR 在脑 IR 损伤发病机制中的核心作用。CFTR 通过线粒体氧化应激依赖性途径调节脑 IR 后的神经元凋亡。CFTR 介导的线粒体氧化应激的机制需要进一步研究。关键信息：CFTR 激活可保护脑组织免受 IR 诱导的凋亡和氧化应激。CFTR 破坏增强了 HO 诱导的神经元凋亡，CFTR 缺失导致线粒体氧化应激。CFTR 通过线粒体氧化应激调节 IR 诱导的神经元凋亡。CFTR 可能是脑 IR 损伤的潜在治疗靶点。
