环形RNA介导U1 snRNA调控神经祖细胞分化的机制

Due to the low reproducibility of nerve cells, the cell regeneration therapy has been considered as the most promising treatment for neurodegenerative diseases. Precise control of neuronal differentiation is necessary for the generation of a variety of neurons. Several studies have indicated that the expression of circRNAs is closely related to neuronal differentiation, however, the biogenesis and the biological function of the circRNAs are still unknown. Based on research progress and our preliminary data, we speculate that circRNAs play an important role in mediating U1 snRNA, which regulate the differentiation of neural progenitor cells. To have a better understanding of this issue and to elucidate the underlying mechanisms, we are going to investigate how circRNAs mediate U1 snRNA-regulated differentiation of neural progenitor cell and further analyze the molecular mechanism involved in the expression of circRNA by RNA splicing. The study is performed to explore the regulatory mechanisms based on the methods of RAP-RNA, RNA-seq, RNA-FISH, RNA pull down, protein mass spectrometry, ChIP-seq and so on. This study will not only help to understand the mechanisms of circRNA expression and function, but also benefit for detecting new targets for the management of neural progenitor cell differentiation. Our results will provide new knowledge for the cell therapy of neurodegenerative diseases.

由于神经细胞的低可再生性，细胞再生疗法被认为是最具发展潜力的神经退行性疾病治疗手段，而精确控制神经分化是产生多种神经元的必要条件。有研究显示circRNA的表达与神经分化密切相关，但其生物学起源及功能尚不明确。基于研究进展和前期研究结果，我们推测circRNA在介导U1 snRNA调控神经祖细胞分化过程中发挥重要作用。为深入探讨此问题并明确相关机制，我们将采用RAP-RNA、RNA-seq、RNA-FISH、RNA pull down、蛋白质谱和ChIP-seq等方法探究circRNA介导U1 snRNA调控神经祖细胞分化的机制，明确U1 snRNA通过RNA剪接调控circRNA表达的分子细节。本研究不仅有助于加深对circRNA表达和功能机制的理解，促进对circRNA基本活动规律的认识，也有助于发现控制神经祖细胞分化的新靶点，为神经退行性疾病的细胞治疗研究提供新的理论依据。

先前的研究显示circRNA的表达与神经分化密切相关，但其生物学起源及功能尚不明确。由于中枢神经细胞的低可再生性，细胞再生疗法被认为是最具发展潜力的神经退行性疾病治疗手段，而精确控制神经分化是产生多种神经元的必要条件。基于本项目的研究结果，我们证实circRNA在介导U1 snRNA调控神经祖细胞分化过程中发挥重要作用，并明确了circRNA调控下游基因表达的机制。大多数神经祖细胞的circRNA是通过可变剪接产生的，这是真核基因表达过程中的一个重要步骤，由U1小核核糖核蛋白或I/II类核酶催化。反向剪接是一种顺式调控元件，能够调节剪接和催化循环，该过程的正确执行需要功能正常的剪接体。U1 snRNA的表达失调会导致U1 snRNA在细胞核内聚集并伴随细胞内广泛的RNA剪接异常，进而导致神经元功能异常。随着细胞内U1 snRNA表达水平的增加，更多的U1 snRNA会在内含子上的U1 snRNA的结合位点上结合，表明U1 snRNA通过控制U1 snRNA到新生转录本的募集来调节神经元中的RNA剪接和基因表达。此外，我们发现反向剪接的效率与正向剪接相比非常低，这可能是由于剪接体在反向剪接时组装不当造成的。这些研究结果不仅有助于加深对circRNA表达和功能机制的理解，促进对circRNA基本活动规律的认识，也有助于发现控制神经祖细胞分化的新靶点，为神经退行性疾病的细胞治疗研究提供新的理论依据。