纹状体诱导神经干细胞分化为多巴胺能神经元的机制研究

Neural stem cells have generated increased attention because they may provide an.unlimited sourse of replacement tissue for treating many human diseases. Little is known about the mechanism to which nueral stem cells can differentiate into enough number neurons for treating CNS degenerative disease like parkinson’s disease. There are numerous parallels between the heamatolymphopoietic and nervous systems in terms of the mechanisms regulating their development. We proposed that neural stem cells (NSCs) may respond to the microenvironmental signals provided by bone marrow stromal cells (BMSCs) which regulate the differentiation and .maturation of hematolymphopoietic stem cells. First, we isolated and proliferated BMSCs from the femur and tibia, and NSCs from the midbrain of SD rats, and then investigated the effects of BMSCs on the differentiation of NSCs into neurons, astrocytes and oligodendrocytes by directly plating neurospheres on BMSC monolayers in serum-free conditions. The results confirmed that BMSCs induced NSCs to differentiate selectively into neurons. The percentage of neurons significantly increased in 7 d in vitro co-cultures of NSCs and BMSCs as compared to NSCs.cultures alone. When the duration of the cultures was extended to 12 d in vitro, BMSCs enhanced the survival of neurons derived from these NSCs; our investigation then focused on the underlying.mechanism for this effect of BMSCs. NSCs were cultured with BMSC conditioned-medium and co-cultured with membrane fragments of live BMSCs or paraformaldehyde fixed BMSCs, the inducing activity of BMSCs was solely detectable in BMSC conditioned-medium, indicating that.soluble factors secreted by BMSCs were responsible for its effect on the neuronal differentiation of NSCs. Therefore, BMSCs may provide a powerful tool for therapeutic neurological applications.

本项目拟采用免疫组织化学、原代细胞培养技术，使用来自成年大鼠中脑的神经干细胞，通过逐级分解纹状体微环境，对纹状体定向诱导神经干细胞分化为多巴胺能神经的机质进行研究，以期部分阐明纹状体诱导神经干细胞分化为多巴胺能神经元表型的机制。为使用神经干细胞治疗帕金森氏病奠定一些理论基础，对最终操纵神经干细胞体内外定向分化也具有重要意义。