Yu Xiaomeng, Wang Xiaoyi, Xie Yinyin, Peng Tingting, Lian Yajun, Wang Cui, Xie Nanchang
Department of Neurology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
Department of Clinical Laboratory, Key Clinical Laboratory of Henan Province, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
Neurochem Res. 2023 Jul;48(7):2253-2264. doi: 10.1007/s11064-023-03910-2. Epub 2023 Mar 16.
The mitochondrial unfolded protein response (mtUPR) has been shown to restore protein homeostasis and cell function under stress, and recent studies have confirmed that the activating transcription factor 4 (ATF4) regulates mtUPR. However, the role of ATF4-mediated mtUPR in a hippocampal neuronal culture model of seizures remains unclear. Our results showed that the expression of mtUPR-related proteins (HSP60 and CLpP) increased in primary hippocampal neurons with seizures induced by a magnesium-free solution, suggesting mtUPR activation. Furthermore, ATF4 overexpression by lentiviral vector transfection enhanced the expression of HSP60 and CLpP, whereas ATF4 low expression by lentiviral vector transfection weakened the expression of HSP60 and CLpP. In addition, ATF4 overexpression increased neuronal viability and reduced seizure-induced apoptosis. ATF4 overexpression reduced reactive oxygen species (ROS) production and improved mitochondrial membrane potential damage during seizures. Moreover, ATF4 overexpression reduced the BCL2-associated X protein (Bax) expression and increased the expression of B-cell lymphoma 2 (BCL2). In contrast, ATF4 expression showed the opposite trend. In conclusion, our results showed that ATF4-mediated mtUPR may delay the cascade activation of apoptotic pathways by reducing ROS-mediated oxidative stress, thereby attenuating seizure-induced stress injury.
线粒体未折叠蛋白反应（mtUPR）已被证明在应激状态下可恢复蛋白质稳态和细胞功能，并且最近的研究证实激活转录因子4（ATF4）调节mtUPR。然而，在癫痫发作的海马神经元培养模型中，ATF4介导的mtUPR的作用仍不清楚。我们的结果表明，在无镁溶液诱导癫痫发作的原代海马神经元中，mtUPR相关蛋白（HSP60和CLpP）的表达增加，提示mtUPR被激活。此外，通过慢病毒载体转染过表达ATF4可增强HSP60和CLpP的表达，而通过慢病毒载体转染低表达ATF4则会减弱HSP60和CLpP的表达。另外，ATF4过表达可提高神经元活力并减少癫痫发作诱导的细胞凋亡。ATF4过表达可减少癫痫发作期间活性氧（ROS）的产生并改善线粒体膜电位损伤。此外，ATF4过表达可降低BCL2相关X蛋白（Bax）的表达并增加B细胞淋巴瘤2（BCL2）的表达。相反，ATF4表达呈现相反的趋势。总之，我们的结果表明，ATF4介导的mtUPR可能通过减少ROS介导的氧化应激来延迟凋亡途径的级联激活，从而减轻癫痫发作诱导的应激损伤。
