肌萎缩侧索硬化（ALS）是一种严重致死性神经变性疾病，研究表明miRNA 异常表达参与了ALS的发病，然而其具体机制不清。申请者前期工作发现 ALS 患者和SOD1G93A小鼠miR-183表达降低，细胞实验发现miR-183影响了NSC34细胞的增殖和凋亡，结合基因表达谱结果，推测miR-183可能通过EGR1介导的PI3K-Akt和p53通路在ALS运动神经元的死亡中发挥重要作用。本研究拟通过干扰NSC34细胞或小鼠原代神经元中miR-183或EGR1的表达，观察这两种细胞生物行为学的改变，检测PI3K-Akt和p53通路相关分子的表达变化，明确miR-183-EGR1在神经元凋亡坏死中的作用机制；同时在动物水平，检测不同时期miR-183过表达/表达抑制的SOD1G93A小鼠脊髓、大脑皮层运动神经元的丢失，胶质细胞的增生，探讨miR-183对ALS发生发展的影响。

Amyotrophic lateral sclerosis (ALS）is a fatal neurodegenerative disease that mainly affects pyramidal upper motor neurons in the motor cortex and lower motor neurons in the brainstem and spinal cord. Accumulative evidences suggest dysregulation of microRNAs has emerged as a new mechanism involved in ALS pathogenesis, although the accurate pathogenic mechanism of ALS remains unclear. In our previous study, compared with PD and healthy controls, we found the expression of miR-183 was specifically decreased in ALS. In addition, the lower-expression of miR-183 was also found in the leukocytes and gastrocnemius of the pre-symptomatic (60 days after born) and early symptomatic (90 days after born) stage SOD1G93A mice than that in wild type mice. In cell experiment, we found over-expression of miR-183 promoted NSC34 cells proliferating, and suppressed NSC34 cells apoptosis by transfected the miR-183 mimics. Combination the results of the mRNA microarray by transfecting miR-183 mimics or miR-183 inhibitor and bioinformatics analysis, we speculate miR-183/EGR1/PI3K-Akt and miR-183/EGR1/p53 axis play an important role in the development of ALS. In the present project, we plan to fully explore the role and pathogenesis of miR-183 in amyotrophic lateral sclerosis by cell and animal experiments. In the NSC34 cell and primary mice neuron, we will analyze the cell cycles, proliferation and apoptosis after over-expression or down-expression of miR-183 or EGR1, and detect the expression of the relevant mRNA/protein of PI3K-Akt and p53 signaling pathway, in order to certify the pathogenic mechanism of miR-183-EGR1 involve in the neuronal death. In addition, we will prepare over-expression or down-expression of miR-183 of SOD1G93A mice by medullary cavity injection, the loss of neuron and proliferation of neuroglia will be tested in the different stage of these mice after born, such as 30 days, 60 days and 90 days, in order to reveal the role of miR-183 are related to the development and progression of ALS. Overall, the results of the present project will provide novel insights into the mechanisms of miR-183 contribute to ALS, and identify genes and pathways as potential targets for further development of the therapeutic reagents.