Project 4

神经干细胞迁移在缺血性卒中后脑修复中的作用 我们的长期目标是为直流电场作为一种新的中风患者脑修复和神经保护疗法的最终发展提供证据。脑缺血可诱导脑室下区神经干/祖细胞(NSPC)的增殖。尽管新生成的NSPC可以分化为迁移到受损区域的新神经元，但只有一小部分新神经元迁移到受损区域，这是阻止内源性神经再生的关键屏障。然而，在确定促进NSPC迁移以克服障碍的指导线索方面几乎没有做出什么努力。我们的研究表明，EF可能是这样的指导线索之一。由于EF在人类中枢神经系统中具有潜在的安全性，EF刺激可能被开发为脑修复和神经保护治疗。我们已经证明，EF刺激在体外引导和加速NSPC向阴极的迁移，这种迁移需要N-甲基-D-天冬氨酸受体(NMDAR)与Rho GTPase rac1/actin信号的相互作用。功能性NMDAR被重新分布到EF暴露的NSPC的阴极侧，表明极化的NMDAR在介导EF定向的NSPC迁移中发挥了作用。重要的是，我们的初步研究表明，在活体大鼠中风模型中，非侵入性EF刺激促进SVZ NSPC衍生的新神经元向阴极方向迁移到缺血边界区。在本项目中，我们将继续使用大鼠中风模型来检验这一假设，即EF刺激引导和加速SVZ NPSC衍生的功能性新神经元迁移到受损的脑区，并通过NMDAR依赖的rac1/肌动蛋白信号通路促进功能恢复。我们将首先确定EF刺激是否引导功能性新神经元迁移到受损的脑区，并改善中风动物的神经行为结果。然后，我们将确定NMDAR/rac1/肌动蛋白信号在介导EF诱导的NSPC在脑缺血中的迁移中的作用。这项研究的结果将引导我们理解EF如何在卒中模型中指导NSPC的迁移，这对于EF刺激作为一种新的脑修复和/或神经保护策略的最终发展是至关重要的。

Role of neuronal stem cell migration in brain repair following ischemic stroke Our long-term goal is to provide evidence for the ultimate development of direct-current electrical field (EF) as a novel brain repair and neuroprotection therapy for stroke patients. Brain ischemia induces proliferation of neural stem/progenitor cells (NSPCs) in the subventricular zone (SVZ). Although the newly generated NSPCs can differentiate into new neurons that migrate to the damaged regions, only a fraction of the new neurons is found to migrate to the damaged area, which is a critical barrier to prevent endogenous neuroregeneration. Yet, little effort has been made towards identifying guidance cues that promote NSPC migration to overcome the barrier. Our study suggests that the EF may be one such guidance cue. As EF is potentially safe in human CNS, EF stimulation may be developed as brain repair and neuroprotection therapy. We have shown that EF stimulation guides and accelerates NSPC migration towards the cathode in vitro, and this migration requires interaction of N-methyl-D-aspartate receptors (NMDARs) with Rho GTPase Rac1/actin signaling. Functional NMDARs are redistributed to the cathode side of EF-exposed NSPCs, suggesting a role of polarized NMDARs in mediating EF-directed NSPC migration. Importantly, our preliminary study has shown that a non-invasive EF stimulation promotes migration of SVZ NSPC-derived new neurons, towards the cathode direction, to the ischemic boundary zone in an in vivo rat stroke model. In this project, we will continue to use the rat stroke model to test the hypothesis that EF stimulation guides and accelerates the migration of functional, SVZ NPSC-derived new neurons to the damaged brain region and promotes functional recovery through NMDAR-dependent Rac1/actin signal pathway. We will first determine whether EF stimulation directs migration of functional new neurons to the damaged brain region and improves neurobehavioral outcome of stroke animals. We will then determine the role of NMDAR/Rac1/actin signaling in mediating EF-induced NSPC migration in the ischemic brain. The outcome of this study will lead us to understand how EF directs NSPC migration in stroke model in vivo, which is essential for the ultimate development of EF stimulation as a novel brain repair and/or neuroprotection strategy.