miR-7-1-3p调控神经元自噬功能减退在脑衰老和帕金森病发病中的机制研究

Parkinson's disease (PD) is the most common disabled degenerative disease of the central nervous system in the elderly. Aging and autophagy defect are closely related to PD pathogenesis. But the molecular mechanism of neuronal autophagy defect in aging, PD pathogenesis, and aging developing to PD is unclear. In our previous work, we found that plasma exosomal miR-7-1-3p was decreased more obviously in PD patients compared to controls during aging. in vitro and in vivo experiments, inhibition of miR-7-1-3p led to upregulation of ACK1 gene, and the activation of the AKT/mTOR signaling pathway.Therefore, we hypothesize that the down-regulation of miR-7-1-3p can up-regulate ACK1 expression, leading to the activation of AKT/mTOR signaling pathway and aggravating autophagy defect,aging and PD, We would further elucidate the role of miR-7-1-3p—ACK1—AKT/mTOR in the autophagy defect of aging and PD, in order to identify the key molecular mechanism of brain aging and its evolution to PD. This study will provide new targets for the early diagnosis and treatment of PD.

帕金森病（PD）是中枢神经系统最常见的致残性退行性疾病，衰老和AKT/mTOR通路介导的自噬功能减退与PD发病密切相关。但是神经元自噬功能减退在衰老、PD发病、以及衰老向PD演变中的作用和分子机制尚不清楚。我们发现健康对照和PD患者血浆外泌体miR-7-1-3p均呈现年龄依赖性下降，但在PD患者下降更为显著。我们在离体培养的神经元及PD小鼠模型脑组织抑制miR-7-1-3p可使ACK1基因表达上调、AKT/mTOR通路激活增强。我们推测神经元miR-7-1-3p表达下降引起靶基因ACK1过度表达，导致AKT/mTOR通路过度激活，诱导自噬功能减退，参与衰老发生和PD发病。我们拟深入研究miR-7-1-3p—ACK1—AKT/mTOR通路所致神经元自噬功能减退在脑衰老、PD发病、以及衰老向PD演变中的作用，旨在发现脑的衰老及其向PD演变的关键分子机制，为PD的早期诊断和防治提供新靶标。

帕金森病 (Parkinson’s disease, PD) 是一种神经退行性疾病，其主要特征是黑质多巴胺能 (DA) 神经元进行性死亡引起的纹状体多巴胺释放减少，导致运动功能障碍及认知、情绪障碍等。PD的发病机制极其复杂，其中小胶质细胞介导的神经炎症对PD的发生发展具有重要影响。微小RNA（miRNA）miR-218-5p在多种神经系统疾病中发挥重要作用，但是在PD及小胶质细胞介导的神经炎症中的作用尚未明确。本研究发现在1-甲基-4-苯基-1,2,3,6-四氢吡啶(1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine,MPTP)诱导的急性PD小鼠模型黑质中miR-218-5p表达显著下降。通过黑质立体定位注射miR-218-5p agomir构建miR-218-5p过表达的急性PD小鼠模型，我们证实miR-218-5p在黑质过表达可减轻PD小鼠黑质多巴胺能神经元的损伤，并抑制黑质区小胶质细胞的活化。为了明确miR-218-5p的作用途径，我们通过RNA高通量测序检测了miR-218-5p黑质过表达的PD小鼠及对照组小鼠的黑质mRNA表达，并进行生信分析。GSEA分析结果提示miR-218-5p过表达调节I型干扰素（I-IFN)反应相关生物学过程。RNA测序和qPCR检测结果显示，与I-IFN反应有关的基因（Irf7，Ddx60，Nlrc5）在PD小鼠黑质表达显著上调，而过表达miR-218-5p抑制这些基因的表达。通过TargetScan软件预测和双荧光素酶报告基因实验验证，我们证实Ddx41是miR-218-5p的靶基因。体外实验结果显示，LPS刺激小鼠小胶质细胞系（BV2）及原代小胶质细胞可显著降低miR-218-5p的表达，过表达miR-218-5p及敲低Ddx41可抑制LPS诱导小胶质细胞的I-IFN反应及炎症因子的表达。我们首次证明了miR-218-5p通过靶向DDX41调节I-IFN反应减轻PD小胶质细胞神经炎症，进而保护多巴胺能神经元免受损伤，为PD的发病机制研究和治疗提供了新的方向。目前已发表和收稿文章4篇，2篇文章已发表于SCI期刊，培养博士生3名，硕士生4名。