三维培养神经干细胞自我更新和分化特征及调控机制的研究

The researches on the characteristics and the mechanism of the differentiation and self-renewal of neural stem cells (NSCs) play an important role in the theory of nervous system development and the therapy of nervous disease.A 3-dimentional (3-D)culture system could provide cells with 3-D structures and extrocellular matixes which are much closer to the in vivo environments compared with the traditional 2-dementional culture system, and avoid the much-influence and long-cycle problems of in vivo experiments. Untill now most 3-D researches on NSCs focus on the committed differentiation and the cell-implantation therapy, however, the researches on the mechanism of the self-renewal and differentiation of NSCs in 3-D culture system are rarely published. In this project, we are trying to investigate the mechanism of self-renewal and differentiation of NSCs cultured in 3-D conditions. We are establishing a 3-D culture system which is suitable for NSCs. In this 3-D culture system, we are planning to detect the proliferation, apoptosis, differentiation and self-renewal of NSCs, and trying to understand the regulation mechanism by detecting the bHLH transcriptional factors expression, the secreation of growth factors and intercelluar signal activation. These investigations may provide us a outline of the regulation mechanism of self-renewal and differentiation of NSCs, and some reference results for the usage of NSCs in the therapy of nervous diseasewe.

神经干细胞自我更新和分化特征及机制的研究为神经系统发育的基础研究和神经系统疾病的治疗提供理论基础和实验依据。三维培养与传统的二维培养相比可以为细胞提供更类似于体内的三维空间环境和胞外基质环境，而且克服了体内实验影响因素多、周期长的问题。目前神经干细胞的三维培养研究集中于定向分化的研究和细胞移植的治疗，针对三维培养神经干细胞自我更新和分化调控机制的研究还非常少见。本项目希望对三维培养神经干细胞自我更新和分化的机制进行初步的探索。我们建立了一个适合神经干细胞的三维培养体系，从转录因子表达、生长因子分泌、胞内信号分子活化等多个角度对神经干细胞自我更新和分化的机制进行探索。本项目的研究可以使我们获得神经干细胞在三维培养条件下自我更新和分化的调控网络初步的认识，为神经干细胞用于神经系统疾病的治疗提供一定的理论基础。

三维培养与传统二维培养相比可能为细胞提供更类似与体内的三维空间环境，本项目计划建立神经干细胞的三维培养体系，通过与二维培养的神经干细胞的对比，挖掘新的调控神经干细胞分化和自我更新的调控机制。经过三年的研究，本项目成功建立了神经干细胞的三维培养体系，发现三维培养可以更好的维持神经干细胞的自我更新。通过神经干细胞的三维培养体系，我们发现了REDD-1通过抑制mTOR信号通路促进了神经干细胞自我更新的维持，microRNA-20通过靶向Rest基因，调控神经干细胞的自我更新。通过三维培养体系，我们发现了二维培养条件下很难发现的调控神经干细胞自我更新的信号分子和microRNA，丰富了我们对神经干细胞调控信号的认识，为三维培养神经干细胞用于神经系统疾病的治疗提供了理论支持。