DNMT3A调控小鼠脊髓损伤后神经再生的机制研究

Spinal cord injury is a common trauma disease which leads to severe harm in human society. How to enhance the neurogenesis and rebuilt the neural circuit after spinal cord injury is the key issue in both the clinical treatments and scientific researches. Our preliminary work has shown that DNMT3A, one of the de novo DNA methyltransferases is required for controlling the development of central neural system and regulating the differentiation and proliferation of neural stem cells. However, it is still not clear whether DNMT3A is also important for neurogenesis in acute spinal cord injury. In this study, we try to build the mice model lacking of DNMT3A expression in central neural system, and then make a spinal cord injury model by clipping T9 spinal cord. After identifying the expression of DNMT3A in spinal cord around the injury, we want to perform microarray and bisulfite sequencing to analyze the transcriptome and methylome of the injured spinal cord tissue in absent of DNMT3A expression, respectively. Furthermore, we are going to carry out the behavior assessment and the electrophysiological recording to compare the motor and sensor outcome between the DNMT3A mutant group and control group. Moreover, it is even interestingly to investigate the neurologic effects of the two DNA methylation related reagents, folic acid and 5-AZA. Prospectively, this project could provide a fundamental evidence of the idea that DNA methylation is involved in acute neural trauma, like spinal cord injury. On the other hand, the experimental attempt of epigenetic reagents might be allowed to improve the functional recovery of spinal cord injury patients in future.

脊髓损伤是严重危害社会公共健康的疾病。如何提高神经再生能力、促进神经环路重建是脊髓损伤治疗和研究工作中面临的重要科学问题。前期研究发现，作为de novo DNA甲基化转移酶（DNMTs）之一的DNMT3A与神经再生相关基因调控密切相关并且在调控神经细胞增殖与分化过程中发挥了重要作用。但是在脊髓损伤发生后，神经再生障碍是否与DNMT3A调控相关还不清楚。本课题试图建立DNMT3A中枢神经系统特异性缺失型小鼠模型，通过进行神经发育相关基因表达谱分析，检测在DNMT3A缺失情况下上调和下调基因的特点和分类，寻找影响最大的神经发生相关信号传导通路；同时通过亚硫酸盐测序法进行DNA甲基化模式分析，重点研究损伤后DNA甲基化改变模式，从基因调控的本质上分析脊髓损伤后病理机制和神经再生障碍原因。最后使用DNA甲基化相关药物进行治疗研究，通过比较两组间行为学评分和电生理学综合评价,探索脊髓损伤病理机制。

脊髓损伤是严重危害社会公共健康的疾病。如何提高神经再生能力、促进神经环路重建是脊髓损伤治疗和研究工作中面临的重要科学问题。本项目基于前期研究基础，重点关注脊髓损伤后表观遗传学调控机制DNA甲基化的变化情况，并进行了相关干预研究。通过对DNA进行全基因组测序和生物信息学分析，结果发现DNA甲基化在小鼠脊髓损伤与修复分子病理机制中发挥了重要的调控作用。小鼠脊髓损伤后受损脊髓呈现高甲基化状态，通过注射DNA甲基化抑制剂——5AZA可以发挥神经保护功能，是未来治疗脊髓损伤的一种新的探索。目前国际脊髓损伤研究领域尚未有针对全基因组DNA甲基化分析研究，本项目首次通过RRBS技术展示了这一病理机制全图，对未来相关工作具有重要的科学意义。