有丝分裂检验点与中枢神经系统非整倍体神经细胞的起源

在正常中枢神经系统中发现10-30%的神经细胞是非整倍体，远高于身体其它组织。非整倍体神经细胞可能贡献神经细胞多样性或导致神经疾病。中枢神经为什么有高比例的非整倍体神经细胞？我们长期研究消除非整倍体产生的机制有丝分裂检验点(SAC)，发现SAC基因在干细胞神经分化中系统性地下调，推测神经分化抑制SAC以增加非整倍体发生和神经细胞多样性。项目首先研究体内中枢神经非整倍体细胞的染色体改变是否具有染色体倾向性及SAC组分的表达、定位、修饰、相互作用等工作机制的变化；然后在体外神经分化中用SAC基因干扰或缺陷突变体诱导产生非整倍体，研究非整倍体神经细胞是否由SAC变化导致，分析体外分化中非整倍体神经细胞的染色体改变特征及SAC工作机制和中枢神经系统是否一致；最后研究哪些神经分子调控哪些SAC组分及如何调控。项目从非整倍体神经细胞的染色体改变特征及发生机制二个新视角揭示非整倍体神经细胞的生物学意义。

In the central nervous system, 10-30% of neural stem cells(NSC), neural progenitor cells(NPC), neurons and glial cells were found to be aneuploidy, which is significantly higher than that of any other normal tissue cells. These aneuploid neural cells may contribute to diversity of neural cells, the complexity of brain and neural disease development. Why and how are these aneuploid neural cells generated? The causes and chromosomal constitution for the aneuploid neural cells are not defined so far. We have been working for years on the mitotic spindle assembly checkpoint (SAC), which is the major mechanism preventing the generation of aneuploidy, and found that the expression of multiple key genes of SAC were downregulated simultaneously in the neural differentiation of human embryonic stem cells. We hypothesize that neural differentiation inhibits SAC function, improves the frequency of the aneuploidy and enables the potential diversity of neural cells. In this proposal we will define the chromosomal alteration feature in aneuploid neural cells and characterize whether there are alterations of SAC components in terms of gene expression, protein modification, cellular distribution, centromeric localization and protein interactions in neural differention, when compared to that of SAC in other normal tissue cells. We will investigate whether and how the alterations in SAC contribute to the generation of aneuploid neural cells, with the gene knockdown or expression of mutants of SAC genes. We will further investigate what key neural differention molecules regulate the SAC system and what components in the SAC system are regulated. The study will reveal the chromosomal constitution feature of aneuploid neural cells, the alterations of SAC signaling in neurogenesis, the role of the interplay of SAC and neural differentiation mechanisms in the genesis of aneuploid neural cells. The study will generate valuable data critical for understanding the biological and clinic relevance of the aneuploid neural cells.