miR-124调控Calpain1基因表达参与脊髓损伤修复的作用机制研究

Spinal cord injury (SCI) is a common injury to the motor system, often lead to paralysis of the patient, which bring heavy burden to the society and family. Its treatment has been a medical problem, It is urgent to explore the mechanism of spinal cord injury repair to provide the theoretical basis for the treatment of the SCI. Study reported that miR-124 expression was down regulated in SCI and Calpain1 can induce apoptosis of spinal cord cells, both of them may be involved in the process of spinal cord injury. We found in previous studies, low expression of miR-124 in neurons of the SCI, but spinal cord injury repair process accelerated after miR-124 overexpression. Prediction of miR-124 target based on calpain1, prompt miR-124 to participate in the process of the SCI repair, but its mechanism is not clear, the process may be involved in the regulation of Calpain1 gene expression. This project intends to build a miR-124 high expression / silence model of SCI, to study the function of miR-124 in the repair of spinal cord injury and its role in the regulation of calpain1 in the repair of spinal cord injury. We’ll explore the effects of miR-124 on the repair of the SCI and its mechanism from the molecular, cellular and general level, to provide new ideas and targets for treatment of the SCI .

脊髓损伤( SCI)是常见运动系统创伤，常导致患者瘫痪，给社会和家庭带来沉重的精神和经济负担。其治疗一直是医学难题，探索脊髓损伤修复机制为其治疗提供理论基础迫在眉睫。研究报道miR-124在脊髓损伤时表达下调，Calpain1可诱导脊髓细胞凋亡，提示两者均可能参与脊髓损伤进程。我们前期研究发现，miR-124在脊髓损伤部位的神经元细胞中低表达，过表达miR-124后脊髓损伤修复进程加速，预测miR-124的靶基因是calpain1，提示miR-124参与到脊髓损伤修复过程中，但其作用机制不清，可能通过调控Calpain1基因表达来参与该过程。本项目拟通过构建miR-124高表达/沉默脊髓损伤模型，研究miR-124在脊髓损伤修复中的功能，以及其调控calpain1参与脊髓损伤修复的作用机制。从分子、细胞、整体水平探讨miR-124对脊髓损伤修复的影响及机制，为脊髓损伤治疗提供新思路和靶点。

1 研究背景.脊髓损伤(SCI)是一种常见的破坏性神经系统疾病。脊髓损伤后会发生神经元炎症、氧化应激、凋亡，以及轴突变性、胶质瘢痕形成、空化等病理变化。SCI后脊髓再生和功能恢复受限，原因是损伤部位的微环境不通透，重建脊髓损伤后的神经再生微环境以恢复神经功能是一个巨大的挑战。microRNA是一类短非编码RNA(18-25个核苷酸)，与靶mRNA的3’UTR结合影响mRNA翻译，调控多种生物学过程。数种miRNA在脊髓损伤后差异表达，参与继发性损伤反应。其中miR-124-3p已被报道在脊髓损伤修复中发挥重要作用，但miR-124治疗脊髓损伤的调控分子和潜在的分子机制尚不清楚。.2 主要研究内容和结果.本研究旨在探讨miR-124介导脊髓损伤修复的潜在分子机制。选取SD大鼠为研究对象，建立了miR-124脊髓损伤模型大鼠，在脊髓损伤模型构建之前给予了miR-124-3p agomiR，评估miR-124-3p在减轻脊髓损伤SD大鼠脊髓功能中的作用以及对周围神经元细胞凋亡的影响，建立了8个转录组进行RNA测序，通过生物信息学技术研究miR-124调控的调控网络和潜在分子机制。我们验证了agomiR-124对大鼠脊髓损伤的保护作用，确定了差异表达(DE)mRNA，使用qPCR验证部分mRNA。使用GO和KEGG途径分析预测这些DE mRNA的潜在功能及其可能的信号传导途径。研究了排名前20位的DE基因，确认了SCI之后以及agomiR-124处理后基因的表达改变。.本研究发现上调miR-124-3p能够通过靶向并下调Calpain1抑制氧化应激反应导致的脊髓神经元细胞凋亡并促进脊髓功能的恢复。miR-124改变了基因表达谱，许多基因参与了miR-124介导的SCI修复，我们也预测了miR-124/Calpain/Cortactin调控轴的存在及作用。其中，基因Nploc4，Yme111，LOC103693564，Aspa，Ebb1212，LOC100911685，LOC100910833，Smarcc1和Tal1对于脊髓损伤修复有重要意义，低水平的Tal1可以促进神经元前体细胞的增殖，抑制其分化。.3 科学意义.本研究的发现为脊髓损伤的治疗提供了新的靶点，将有助于脊髓损伤机制的阐明和治疗药物的研发。我们的发现有助于更深入地了解miR-124介导脊髓损伤修复的机制。