lncRNA-HOTAIR 对神经干细胞生物学行为调控作用的研究

Nowadays, many researchers devote to studying cerebral regeneration and repairing insulted cerebral tissue with neural stem cells (NSCs). The experimental and preclinical studies showed that NSCs have the ability of differentiating into neurons, promoting angiogenesis, and integrating and restoring neural pathways to restore the function of damaged parts of the brain. However, it is difficult to achieve the desired results of NSCs treatment for ischemic stroke because most of NSCs are not able to migrate into the infarct zone of brain. How to improve the migration rate of NSCs has become the key issue and must be solved before clinical applications. Recent studies have demonstrated that long non-coding RNAs (lncRNAs) are crucial for normal NSCs self-renewal and cellular differentiation, but how lncRNAs gene expression is controlled by the key transcriptional regulators of NSCs has not been clearly established. Till now, no studies have focused on the role of lncRNA HOTAIR in promoting migration and inhibiting apoptosis effects of NSCs after transplantation. Our previous study demonstrated that overexpression of HOTAIR in NSCs could reduce apoptosis and promote the migration of NSCs via targeting miRNA-9/CXCR4 cell signaling pathway in hypoxic condition. So, we hypothesize that up-regulation of HOTAIR in NSCs plays an important role in the regulation of NSCs survival and migration in brain infarction ischemic stroke area. To confirm this hypothesis, we will establish a mouse brain ischemia model and reveal the effects of HOTAIR in NSCs in treatment of ischemia cerebral damage via the combination of cellular biological techniques and molecule biological methods. It is reasonable to speculate that HOTAIR, the novel but practical regulator of NSCs transplantation for ischemic brain damage, introduces a promising strategy for the treatment of ischemic stroke patients.

目前，神经干细胞（NSCs）在缺血后神经细胞再生及神经组织修复中的作用已经成为生命科学领域研究的热点之一。然而，由于 NSCs归巢率低且无法适应脑梗死区微环境而死亡，难以达到预期的治疗效果。前期研究发现lncRNA HOTAIR在脑梗死中显著升高且能诱导NSCs向脑梗死区迁移，提示HOTAIR在NSCs缺血后神经细胞再生及神经组织修复中可能发挥重要的调节作用。项目组进一步筛选出其潜在靶分子miRNA-9及下游的信号通道蛋白CXCR4。基于以上研究，我们推测HOTAIR是NSCs移植治疗缺血性脑损伤关键靶点。为证实这一假说，项目组首次以HOTAIR为靶点，应用慢病毒基因过表达和基因沉默技术，采取细胞生物学和分子生物学相结合的方法，从分子、细胞、动物多层次系统阐明HOTAIR/miRNA-9/CXCR4信号转导通路在调控NSCs生物学行为中的作用，为NSCs治疗缺血性脑损伤提供新思路、新靶点。

目前，通过神经干细胞(NSCs)移植进行外源性神经细胞再生及神经组织修复重建，是针对病因的特异性治疗手段，有比较好的应用前景。然而，由于NSCs归巢率低且无法适应脑梗死区微环境而死亡，难以达到预期的治疗效果。本项目围绕神经干细胞治疗缺血性脑损伤的关键问题，主要的研究内容包括：采用氧糖剥夺法建立NSCs的体外脑缺血模型，筛查在神经干细胞缺氧诱导模型中显著变化的lncRNA；观察沉默和过表达lncRNAHOTAIR在缺氧NSCs增殖、凋亡、迁移方面的调控作用；采用慢病毒基因过表达和基因沉默技术验证HOTAIR对miRNA9和下游的信号蛋白CXCR4等的靶向调控作用；检测HOTAIR/miRNA9/CXCR4信号轴在NSCs修复脑梗死区神经元调控中的调控作用。结果表明，过表达干细胞中LncRNAHOTAIR促进神经干细胞在缺氧环境中的增殖，减轻细胞凋亡；过表达LncRNAHOTAIR有利于神经干细胞在缺氧环境中的迁移；过表达LncRNAHOTAIR通过靶向调控miRNA9及CXCR4的表达调控神经干细胞的存活及增殖；在体实验证实了过表达lncRNAHOTAIR明显改善神经干细胞移植MCAO模型小鼠的神经功能。本研究阐明脑梗死时HOTAIR/miRNA9/CXCR4调控网络对NSCs生物学行为的影响，为NSCs移植治疗脑缺血提供新的理论基础和药物治疗靶点。