lincRNA通过影响神经元相关基因的染色质结构调控胶质细胞向神经元的转分化

During injury of the central nervous system (CNS), glial scar formation occurs in accompany with neuronal cell death and functional deterioration. Glial scars, on one hand serve to limit the spreading of inflammatory cells after injury, and on the other hand form a physical barrier to prevent regeneration of nerve fibers and inhibit repair of the nervous system. We believe that being able to reduce glial scar formation and at the same time enhance neurogenesis will greatly facilitate repair and functional recovery of the injured CNS. In this application, we plan to use a transdifferentiation strategy, using a set of key factors to, in vitro and in vivo, direct convert reactive astrocytes into functional new neurons that can form new synaptic network. More importantly, we would like to reveal the epigenetic and transcriptome changes during this process, with a focus on delineating the participating lncRNAs. Using a newly invented RICH-PET technology, we aim to uncover the lncRNAs acting on neural lineage gene-associated chromatins. From this pool of lncRNAs, we will perform gain and loss of function experiments to define the candidate lncRNAs, which can facilitate the trans-differentiation process in vitro and in vivo. Our work will provide solid basis for future usage of the trans-differentiation strategy to treat neural trauma.

在脑和脊髓损伤区域，伴随着神经元的死亡和功能退化，星形胶质细胞会活化、增生形成胶质疤痕。如何保留胶质疤痕在损伤区域抗炎的良性作用，同时消除其后期对神经系统功能重建的不利影响，乃科学研究及临床上急需解决的难题。我们计划通过将损伤区星形胶质细胞在体内转分化为神经元来减弱疤痕形成，同时获得具有修复功能的神经元，从而在最大程度上重塑神经系统功能。首先，我们将结合大量前期工作，通过细胞培养在体外确定从星形胶质到神经元转分化途径的决定性调控因子。重点揭示在此转分化过程中发生的表观遗传及基因表达谱变化，并突出阐明参与此过程的lncRNA的变化与作用。然后通过全新的RICH-PET技术研究并发现调控神经元相关基因所在染色质的lincRNAs并进行功能获得及缺失实验来鉴定在体内及体外进一步提高转分化效率的具体lncRNAs, 此工作将为转分化策略最终应用于人类神经系统损伤的治疗提供理论依据和临床前实验。

在脑和脊髓损伤区域，伴随着神经元的死亡和功能退化，星形胶质细胞会活化、增生形成胶质疤痕。如何保留胶质疤痕在损伤区域抗炎的良性作用，同时消除其后期对神经系统功能重建的不利影响，乃科学研究及临床上急需解决的难题。我们发现了转录因子Ngn1和Tet1蛋白在星形胶质发生中的作用，确定了在星形胶质细胞向神经元转分化过程中起决定性作用的调控因子。采用最优转分化体系，我们对星形胶质细胞，转分化前期、中期的细胞进行了转录组分析和RICH-PET分析，找到了6条与神经元直接相关基因的染色质关联的候选lncRNAs，并通过功能获得及缺失实验在体内和体外鉴定了转分化效率高的lncRNAs。此外，我们采用钳夹法、挫伤法和全横断法构建了用于分析脊髓损伤瘢痕形成病理过程，评价转分化对脊髓损伤小鼠运动功能修复的作用的脊髓损伤的小鼠模型。我们的工作为转分化策略最终应用于人类神经系统损伤的治疗提供依据。