少突胶质细胞转录因子Olig2对精神分裂症海马神经发生的调控及机制

Schizophrenia can cause cognitive dysfunction and hippocampal neurogenesis changes, but the mechanism is still unclear. Study showed that oligodendrocyte and its transcription factors are closely related with schizophrenia. The transcription factor Olig2 is necessary for oligodendrocyte differentiation. Our early study found that in the Olig abnormally expressed animal model of schizophrenia, hippocampal neurogenesis decreased obviously. Therefore, we speculate that dysfunction of oligodendrocyte and its transcription factor Olig may be a factor causing changes of hippocampal neurogenesis in schizophrenia. This project aims to use animal models of schizophrenia and CPZ mediated acute demyelinating mouse model, with Olig2 and the hippocampal neurogenesis as the research targets, based on the explicit expression of Olig2 in hippocampus, to study the effect of Olig2 on the apoptosis, proliferation and differentiation of hippocampal neural cells, and clarify the regulation mechanism of Olig2 on schizophrenia hippocampus neurogenesis by in vivo and in vitro experiments through morphology and molecular biology techniques. We expect to provide the theory basis to clarify the regulation mechanism of oligodendrocytes and myelin on hippocampus neurogenesis in schizophrenia and provide new targets for clinical prevention and treatment of schizophrenia.

精神分裂症可引起认知功能和海马神经发生的改变，但其病理机制尚未明确。研究证实少突胶质细胞及其转录因子与精神分裂症的发生密切相关。转录因子Olig2是少突胶质细胞成熟、分化的必要因子。项目组前期在Olig2表达异常的动物模型中发现海马神经发生降低，因此我们推测转录因子Olig2可能参与了精神分裂症海马神经发生的调控。本项目拟用精神分裂症动物模型和CPZ介导小鼠急性脱髓鞘模型，以Olig2和海马神经发生为研究靶点，采用形态学、分子生物学等技术，通过在体与活细胞水平开展系列研究。在明确海马各区Olig2表达的基础上，阐明Olig2对精神分裂症海马神经细胞凋亡、增殖及分化的调控作用；利用条件性基因敲除和Olig2质粒重建转染等技术，探讨Olig2对精神分裂症海马神经发生的调控机制。本项目不仅有望为精神分裂症认知功能及海马神经发生调控机制的阐明提供新思路，同时为精神分裂症的临床防治提供新靶点。

精神分裂症可引起认知功能障碍及海马神经发生的改变，但其病理机制尚不清楚。本研究旨在阐明Olig2对精神分裂症海马神经细胞凋亡、增殖及分化的调控作用及其机制。在体实验采用CPZ建立脱髓鞘模型，行为学检测认知功能的变化，免疫荧光、Western-blotting、qRT-PCR、流式分别检测海马MBP、GAD67、PV、Sox2、Nestin表达及海马神经细胞的凋亡。离体实验采用MK-801建立海马神经干细胞损伤模型，Western-blotting检测干扰Olig2后Sox2、Nestin、Ki67、NeuN、S100β的表达，流式检测海马神经细胞凋亡。结果：在体实验，与对照组相比CPZ组（1）水迷宫实验定位时间明显延长，总路程明显增加，平均速度无明显差异，小鼠平台象限停留时间和穿越平台次数均明显减少；（2）悬尾实验中小鼠6 min不动时间明显增加；（3）透射电镜观察到大量病理变化的髓鞘，小鼠海马锥体细胞核膜内陷，核质疏松、分布不均匀，突触内突触小泡变大、减少，突触间隙变窄、模糊不清；（4）qRT- PCR和Western-blotting显示小鼠海马MBP、Nestin 表达均减少，PV表达无明显变化；qRT-PCR和免疫荧光标记检测小鼠海马GAD67表达降低、Sox2表达增加；Western-blotting检测GAD67和Sox2的表达均无明显变化。离体实验（1）qRT-PCR和Western-blotting实验结果显示MK-801+Olig2-shRNA组Sox2、Nestin、Ki67的表达增加，NeuN、S100β的表达增加；（2）流式细胞术检测MK-801+Olig2-shRNA组晚期凋亡和总凋亡率较MK-801组均降低，早期凋亡无明显差异。结论：CPZ介导C57BL/6小鼠急性脱髓鞘后海马GABA能神经元损伤，且可引起Olig2的表达增加；而干扰Olig2后海马神经干细胞自我增殖能力加强，促进了海马神经发生。因此，Olig2参与了精神分裂症后海马神经发生的调控。