Wei Xue Wen, Hao Ling Yun, Qi Su Hua
Research Center for Biochemistry and Molecular Biology and Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, 221002, PR China; Department of Laboratory Medicine, Affiliated Municipal Hospital of Xuzhou Medical College, Xuzhou, Jiangsu, 221002, PR China.
Research Center for Biochemistry and Molecular Biology and Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, 221002, PR China; Jiangsu Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou, 221002, PR China.
Brain Res Bull. 2016 Jun;124:123-8. doi: 10.1016/j.brainresbull.2016.04.005. Epub 2016 Apr 14.
S-nitrosylation, the nitric oxide-derived post-translational modification of proteins, plays critical roles in various physiological and pathological functions. In this present study, a rat model of cerebral ischemia and reperfusion by four-vessel occlusion was generated to assess MKK4 S-nitrosylation. Immunoprecipitation and immunoblotting were performed to evaluate MKK4 S-nitrosylation and phosphorylation. Neuronal loss was observed using histological detection. These results indicated that endogenous NO promoted the S-nitrosylation of MKK4. However, application of the exogenous NO donor S-nitrosoglutathione (GNSO), an inhibitor of the neuronal nitric oxide synthase 7-nitroindazole (7-NI), and the N-methyl-d-aspartate receptor (NMDAR) antagonist MK801 diminished I/R-induced S-nitrosylation and phosphorylation. These compounds also markedly decreased cerebral I/R-induced degeneration and death of neurons in hippocampal CA1 region in rats. Taken together, we demonstrated for the first time, that cerebral ischemia/reperfusion can induce S-nitrosylation of MKK4. We also found that inhibiting S-nitrosylation and activation of MKK4 resulted in marked decreases in neuronal degeneration and apoptosis, potentially via NMDAR-mediated mechanisms. These findings may lead to a new field of inquiry to investigate the underlying pathogenesis of stoke and the development of novel treatment strategies.
S-亚硝基化是一种由一氧化氮介导的蛋白质翻译后修饰，在多种生理和病理功能中发挥关键作用。在本研究中，通过四血管闭塞法建立大鼠脑缺血再灌注模型，以评估MKK4的S-亚硝基化。采用免疫沉淀和免疫印迹法评估MKK4的S-亚硝基化和磷酸化。通过组织学检测观察神经元丢失情况。这些结果表明内源性一氧化氮促进了MKK4的S-亚硝基化。然而，应用外源性一氧化氮供体S-亚硝基谷胱甘肽（GSNO）、神经元型一氧化氮合酶抑制剂7-硝基吲唑（7-NI）以及N-甲基-D-天冬氨酸受体（NMDAR）拮抗剂MK801可减少缺血/再灌注诱导的S-亚硝基化和磷酸化。这些化合物还显著减少了大鼠海马CA1区脑缺血/再灌注诱导的神经元变性和死亡。综上所述,我们首次证明脑缺血/再灌注可诱导MKK4的S-亚硝基化。我们还发现抑制MKK4的S-亚硝基化和激活可显著减少神经元变性和凋亡，这可能是通过NMDAR介导的机制实现的。这些发现可能会引发一个新的研究领域，以探究中风的潜在发病机制并开发新的治疗策略。
