lncRNA在脊髓损伤后星形胶质细胞活化中的机制研究

The pathophysiological process of spinal cord injury (SCI) repair is very complicated, in which the functional defects caused by disorder of axonal regeneration is the most important problem of SCI treatment. The external factors that affect the axon regeneration after SCI are the activation of astrocytes and the formation of glial scar. Therefore, fully understanding the molecular mechanism of activation of astrocytes is the key to the treatment of SCI. Recently, a large number of studies have found that the abundance of lncRNA in the spinal cord is associated with process of SCI, which indicates that these lncRNA plays an important role in the pathophysiology of SCI. However, the specific regulation mechanism of lncRNA in damage and repair of SCI system needs a comprehensive study. We completed using lncRNA chip technology to analysis expression profile of different days after damage in the mouse spinal cord, to found mRNA and lncRNA related primary and secondary damage by SCI, and enriched in immune response, cell cycle and cell adhesion. The completion of this project will clarify the mechanism how lncRNA regulation activation of astrocytes and axonal regeneration after SCI, and promote the lncRNA to become a new target for SCI treatment.

脊髓损伤（SCI）后修复的病理生理过程非常复杂，其中轴突再生障碍导致的功能性缺陷，是SCI治疗的首要难题。星形胶质细胞活化后形成胶质瘢痕并含有多种抑制成分是影响SCI后轴突再生的主要因素。最近，大量研究发现脊髓中lncRNA的丰度会伴随SCI的进程发生特异性表达，预示lncRNA在SCI病理生理过程中扮演着重要角色。因此，对于lncRNA在脊髓损伤及修复的具体调控机制，亟待系统全面的研究。研究组前期建立了小鼠SCI垂直打击模型，对损伤后2天，7天和对照组的小鼠脊髓，完成了lncRNA芯片测序。本项目计划利用生物信息学方法，预测与SCI后星形胶质细胞的活化和轴突再生相关的lncRNA，并通过分子生物学实验验证lncRNA上游调控元件与下游靶基因之间的调控关系，系统地阐明lncRNA调控SCI后星形胶质细胞的活化和轴突再生的机制，并且推动lncRNA成为SCI治疗新靶标。

脊髓损伤（SCI）后修复的病理生理过程非常复杂，其中轴突再生障碍导致的功能性缺陷，是SCI治疗的首要难题。星形胶质细胞活化后形成胶质瘢痕并含有多种抑制成分是影响SCI后轴突再生的主要因素。最近，大量研究发现脊髓中lncRNA的丰度会伴随SCI的进程发生特异性表达，预示lncRNA在SCI病理生理过程中扮演着重要角色。因此，对于lncRNA在脊髓损伤及修复的具体调控机制，亟待系统全面的研究。（1）研究组前期建立了小鼠SCI垂直打击模型，对损伤后2天，7天和对照组的小鼠脊髓，完成了lncRNA芯片测序。（2）为进一步明确lncRNA-MEG 调控脊髓损伤的作用，我们使用慢病毒 shRNA-lncRNA-MEG 处理脊髓损伤大鼠，结果表明，在脊髓损伤大鼠模型中 miR-21-5p 的上游基因 lncRNA-MEG 的表达量显著上升。慢病毒 shRNA-lncRNA-MEG 处理后可增加 miR-21-5p 的表达，并减少凋亡相关蛋白的表达，进而抑制神经细胞凋亡，即lncRNA-MEG的表达水平升高在大鼠脊髓损伤模型中有显著性差异。（3）随后，我们发现lncRNA-MEG可以促进PDCD4的表达水平，通过抑制miR-21-5p，导致神经细胞凋亡。此外，使用shRNA可逆转miR-21-5p的作用，抑制PDCD4的作用，降低凋亡相关蛋白的表达。此外，我们发现在OGD细胞模型中，lncRNA-MEG可以通过靶向PDCD4的3'UTR，通过miR-21-5p调节PDCD4的表达。综上所述，我们发现lncRNA-MEG通过miR-21-5p靶向的PDCD4诱导脊髓损伤过程中神经细胞的凋亡。研究结果表明，lncRNA-MEG可能是一个新的SCI治疗靶标。