人体细胞转化的胶质能NSCs在脑功能再生中的作用

Brain injury has become the world's leading health and social problems. The seed cells (A rich source of non-tumorigenic, non-immune rejection, no ethical restrictions, representation of the process of neural development) are the key to the regeneration of brain function. Induced pluripotent stem cells (iPSC) and neurons (iN), which reprogrammed from somatic cells of patients by transcription factors, bring the hope of cure for patients with brain injury. But IPSCs may be tumorigenic, while iN is the terminally differentiated cells, can not reproduce the neurodevelopment. Literature reported glial occurrence of neural stem cells (GNSC) can repeat the process of neural development. Based on this literature, the project assume new reprogramming path can transform human body cells into inducible GNSC (iGNSC), which can repeat the process of neural development. We will choose transcription factor for NSC self-renewal, proliferation-related for different combinations, and transform human fibroblasts as iGNSC, then transplant it into brain injury model of nude mice, and analyze its role in the regeneration of brain function in three levels of the individual, cellular, molecular. The subject base on the normal development of brain, and design new reprogrammed path, transform body cells into iGNSC. The project was designed to improve somatic cell reprogramming strategy, provide new means for brain function regeneration and new ideas for regeneration mechanism.

脑损伤已成为全世界主要健康与社会问题，合适的种子细胞（丰富来源、无致瘤性、无免疫排斥、无伦理限制、能重演神经发育过程）是实现脑功能再生的关键。转录因子诱导病人体细胞重编程来源的多能干细胞(iPSC)和神经元(iN)为脑损伤患者带来了治愈希望。但iPSCs存在致瘤性；iN是终末分化细胞，无能重现神经发育。文献报道胶质发生能神经干细胞(GNSC)可重演神经发育过程。基于此，本项目假设新重编程路径可将人体细胞转化为能重演神经发育过程的诱导型GNSC(iGNSC)。我们选择与NSC自我更新、增殖相关的转录因子进行不同组合，转化人成纤维细胞为iGNSC，将其移植裸大鼠脑损伤模型，从个体、细胞、分子三个层次分析其在脑功能再生中的作用。本课题以脑正常发育为基点，设计新重编程路径将体细胞转化为iGNSC，将完善体细胞重编程策略，为实现脑功能再生提供新手段和揭示再生机制提供新思路。

通过合适的种子细胞（丰富来源、无致瘤性、无免疫排斥、无伦理限制、能重演神经发育过程）修复脑损伤是实现脑功能再生的关键。本研究中我们完成了不同转录因子组合转化成纤维细胞为iG-NSCs：我们实验中筛选出五个关键的因子：Sox2, Bmi-1, TLX, Hes1, and Oct1行不同的组合，供转染诱导成纤维细胞向神经干细胞转型。此外，我们同样发现单一Sox2诱导2-10d后，转化细胞克隆间可以形成网络，并进一步对这些网络表达iG-NSCs进行分时段检测，证明iG-NSCs具有iG-NSCs分化成神经元的能力，并对分化的神经元的进行了相关电生理测试，检测结果显示iNSC分化的神经元具有正常神经元的兴奋性突触后电位。并且iG-NSCs及其分化的细胞可以被SPIO标记，确保脑内活体示踪及移植区化合物代谢的检测，本实验中通过德国Bruker 7.0 T MR扫描仪建立和优化了TBI鼠大脑MR常规扫描及1H-MRS的扫描序列及参数，对脑内细胞移植区进行T2*WI和1H-MRS检测可以发现移植后脑内代谢产物的变化。我们的研究提示新重编程路径可将人体细胞转化为能重演神经发育过程的iGNSC，单一Sox2诱导2-10d后，转化细胞克隆间可以形成网络，并将其移植裸大鼠脑损伤模型，发现其在脑功能再生中的发挥着重要的作用，主要通过建立新的突触及神经环路连接，发挥其恢复受损脑功能的作用。