Botch protects neurons from ischemic insult by antagonizing Notch-mediated neuroinflammation
Botch protects neurons from ischemic insult by antagonizing Notch-mediated neuroinflammation
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Botch 通过拮抗 Notch 介导的神经炎症来保护神经元免受缺血性损伤
DOI：
10.1016/j.expneurol.2019.113028
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发表时间：
2019-11-01
影响因子：
5.3
通讯作者：
Chen, Gang
中科院分区：
文献类型：
--
作者：
Li, Hao;Ma, Junwei;Chen, Gang
由于脑卒中后持续的高发病率和高死亡率，寻求常规溶栓治疗以外的治疗是很重要的。Notch 1的上调参与了脑缺血再灌注损伤后的炎症反应，已有研究报道Botch可结合并阻断Notch 1的成熟。本研究旨在探讨Botch在脑缺血再灌注损伤中的作用及其机制。采用成年雄性Sprague-Dawley大鼠建立大脑中动脉闭塞/再灌注（MCAO/R）模型，采用体外培养的神经元和小胶质细胞进行氧糖剥夺/复氧（OGD/R）处理，模拟缺血/再灌注损伤。结果显示，MCAO/R后，Botch和Notch 1胞内结构域（NICD）蛋白水平升高。此外，过表达Botch后，Notch 1的活化形式NICD的产生减少，而Botch敲除或突变导致NICD产生增加。结果，Botch过表达通过显著降低神经行为表型、改善活化的小胶质细胞的浸润、改善炎性细胞因子释放和抑制神经元细胞死亡而表现出神经保护作用。相反，Botch敲除和突变诱导相反的效果。此外，在神经元和小胶质细胞中，发现OGD/R后NICD移位到线粒体，这刺激了线粒体中活性氧的积累，导致神经元细胞死亡和小胶质细胞活化。Botch过表达可抑制NICD的生成，减少NICD向线粒体的转位，从而抑制神经元细胞死亡并改善神经炎症。总之，我们发现Botch通过拮抗Notch 1诱导的神经元损伤和神经炎症的成熟而发挥神经保护作用，这可能为I/R损伤的治疗提供新的治疗靶点。
Owing to the continued high morbidity and high mortality rate after stroke, it is important to seek treatments other than conventional thrombolysis. Notch1 up-regulation participates in inflammatory responses after cerebral ischemia-reperfusion (I/R) injury, and it has been reported that Botch binds to and blocks Notch1 maturation. In this study, we investigated the role of Botch during cerebral (I/R) injury and explored its potential mechanisms. A middle-cerebral-artery occlusion/reperfusion (MCAO/R) model was established in adult male Sprague-Dawley rats in vivo, and cultured neurons and microglia were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) to mimic I/R injury in vitro. The results showed that protein levels of Botch and the Notch1 intracellular domain (NICD) were increased after MCAO/R. Furthermore, after overexpression of Botch, the generation of the activated form of Notch1, NICD, was decreased, while Botch knockdown or mutation led to an increase in NICD generation. As a result, Botch overexpression exhibited neuroprotective effects by significantly decreasing neurobehavioral phenotypes, improving infiltration of activated microglia, ameliorating inflammatory cytokine release, and inhibiting neuronal cell death. Conversely, Botch knockdown and mutation induced opposite effects. In addition, NICD was found to translocate to the mitochondria after OGD/R in neurons and microglia, which stimulated accumulation of reactive oxygen species in mitochondria and resulted in neuronal cell death and microglial activation. Botch overexpression inhibited the generation of NICD and decreased the translocation of NICD to the mitochondria, which inhibited neuronal cell death and ameliorated neuroinflammation. In conclusion, we found that Botch exerts neuroprotective effects via antagonizing the maturation of Notch1-induced neuronal injury and neuroinflammation, which may provide insights into novel therapeutic targets for the treatment of I/R injury.