mTORC1在iPS来源的神经干细胞修复脊髓损伤中的作用及机制研究

Induced pluripotent stem cells (iPS) are excellent seed cells for spinal cord injury (SCI) since they can differentiate into neural stem cells (NSC) and neurons,. But the low induction efficiency severely limited its' further development. Mammalian target of rapamycin complex 1 (mTORC1) is a key molecule that regulates cell proliferation and differentiation.Activity of mTORC1 pathway can regulate axonal regeneration and neuronal survival. But the mechanism of mTORC1 pathway functioning in SCI repairment with iPS-derived NSC is still unclear. Our pre-experiment results showed that mTORC1 inhibitor (rapamycin) can significantly improve the efficiency of iPS induction and increase the differentiation efficiency of NSC and neuron. In this subject, we intend to clarify the role of mTORC1 in different stages of iPS induction and neural differentiation in vitro through the iPS cells' generation and neural differentiation from TSC1, Raptor knockout mouse fibroblasts (upregulation or downregulation of mTORC1 activity, respectively). At the same time, we use two types of knockout mice SCI models transplanted with NSC to further research the role of mTORC1 pathway in axonal regeneration, formation of functional neural connections and SCI restoration. So it may provides a new method for the prevention and treatment of SCI.

诱导多能干细胞(iPS)可定向分化为神经干细胞(NSC)与神经元，是一种优良的修复脊髓损伤(SCI)的种子细胞，但其诱导效率低。雷帕霉素靶蛋白复合物1(mTORC1)是调控细胞增殖分化的关键分子，可调控轴突再生及神经元存活，但mTORC1是否调控iPS来源的NSC及其修复SCI的作用及机制尚不明确。课题组预实验发现：mTORC1抑制剂雷帕霉素可显著提高iPS诱导效率，并增加其定向分化为NSC与神经元的效率。因此，本课题拟应用TSC1、Raptor基因敲除(分别上调或下调mTORC1活性)的小鼠成纤维细胞，诱导为iPS细胞，并使其定向分化为NSC，阐明mTORC1在体外诱导iPS及神经分化不同阶段的作用；同时制作两种基因敲除小鼠的SCI动物模型，将NSC植入上述模型中，进一步研究mTORC1在轴突再生、形成功能性神经连接和修复SCI中的作用并探讨其分子机制，为SCI防治提供新思路。

诱导多能干细胞(iPS)可定向分化为神经干细胞(NSC)与神经元，是一种优良的修复脊髓损伤(SCI)的种子细胞，但其诱导效率低。雷帕霉素靶蛋白复合物 1(mTORC1)是调控细胞增殖分化的关键分子，可调控轴突再生及神经元存活，但 mTORC1 是否调控 iPS 来源的NSC 及其修复 SCI 的作用及机制尚不明确。本课题组在过去四年中已完成了1、鼠尾尖成纤维细胞经 IPS 细胞向神经干细胞诱导及鉴定2、mTORC1 抑制剂对小鼠成纤维细胞诱导为 IPS 细胞及 IPS 细胞诱导神经干细胞及神经细胞的影响3、神经干细胞与神经支架材料的生物相容性验证4、大鼠 T10 横断模型构建并植入工程化脊髓及功能恢复评价。本课题组后续准备进行IPS细胞的病毒转染和体外神经分化，并制作小鼠的 SCI 动物模型，将 NSC 植入上述模型中，进一步研究 mTORC1 在轴突再生、形成功能性神经连接和修复 SCI 中的作用并探讨其分子机制，为 SCI 防治提供新思路。