HLA区基因多态性与帕金森病的关联分析及其分子机制研究

Gene-age-environment interaction is related to the landmarkable pathogenesis of Parkinson's disease (PD). Variation in HLA-DR/PSMB genomics may contribute to the mechanism in α-syneulein degradation as well as its chronic immune response in the process of antigen presentation during dopaminergic (DA) neuron degeneration. We have preliminarily found that: ①allele frequency of HLA-DRB1*0301 was obviously increased in male PD patients；②rs17587 in PSMB9 gene was associated with female PD；③ α-syneulein accumulation could induce the proteasome dysfunction and compansated immunoproteasome activation in DA neuron to maintain intracellular protein homeostasis. But it is still uncleared about the molecular mechanism of inflammatory response and related immune disorder based on these gene mutations in substantia nigra.Based on our initial data, this study aims to expand case -control study, systematically analyse the polymorphisms of HLA-DR and adjacent PSMB genomics, confirm the related genes and their function in the pathogenesis and development of PD,and explore the mechanism of proteasome dysfunction with compansated immunoproteasome activation and related phosphorylated molecular signal pathways during α-synuclein accumulation in cell model or substantia nigra in vivo under different conditions,so that to disclose the molecular mechanism of DA neuron degeneration involved chronic inflammatory immunological disorder.

帕金森病（PD）是衰老、遗传和环境毒素相互作用的结果，HLA-DR及相邻PSMB区基因可能参与了中枢DA神经元内α-syn蛋白的降解及其免疫应答，在抗原呈递过程中发挥作用。我们初步发现：①男性PD患者HLA-DRB1*0301的携带率明显升高；②PSMB9基因SNP（rs17587）与女性PD相关；③过量α-syn积聚可诱导DA神经元内蛋白酶体功能下降及免疫蛋白酶体代偿性增加，以维持细胞内蛋白代谢平衡。但我们对上述基因变异介导的黑质区炎症反应及其免疫紊乱机制并不清楚。本项目拟在前期基础上，扩大PD病例-对照研究，对HLA-DR及相邻PSMB区基因多态性进行系统分析，以确定相关基因SNPs在PD发生、发展过程中的作用。分析不同条件下，动物黑质区及模型细胞内α-syn积聚过程中，蛋白酶体下降、免疫蛋白酶体上调的机制及相关分子信号的磷酸化改变，从而揭示炎性/免疫紊乱介导DA神经元变性的分子机制。

在前期研究基础上，结合500余PD病例的临床、影像、细胞、免疫组学及临床量表等数据，选取HLA-DR区多个基因SNPs进行DNA测序及等位基因分型分析，基因数据与Hapmap、EBI-HLA数据库其它人群相比较，探讨并确定了7个基因变异在散发性PD发生、发展过程中的作用。以模型细胞为基础，模型动物作验证，分析多个基因变异条件下，模型细胞及动物黑质区α-syn积聚及继发炎症反应过程中，细胞应激介导的蛋白酶体下降，免疫蛋白酶体上调及相关MHC呈递通路的变化，及相关信号分子的磷酸化改变机制，揭示a-syn积聚介导的细胞应激及继发炎症反应和免疫紊乱的信号途径，并着重分析功能分子之间的调控关系。共发表SCI论文18篇，其中>5分4篇。培养博士研究生6名，4名博士后，5名硕士研究生。主要研究成果：①PD患者免疫功能失衡，患者的体液Treg/TH17细胞比例发生改变；免疫相关基因DYRK1A/IGF1/DNMT3b基因SNPs与PD具显著相关性；rs601999、rs11343、rs353116和rs2280104等4个新PD基因位点与中国散发性PD具显著的相关性。②Nurr1抗炎分子与Akt/GSK3β通路分子存在相互调控关系；α-syn聚集可阻止细胞内Wnt信号传导，介导GSK3β磷酸化；③铁离子抑制细胞自噬溶酶体融合，促进α-synuclein聚集及细胞间传递；TFEB为α-synuclein在细胞间传递重要靶点，铁离子抑制TFEB核转位促进α-synuclein细胞间传递；④鉴定了4个PD脑脊液特异miRNAs,包括MiR-144-5p、miR-200a-3p和miR-542-5p，可作为PD潜在的诊断标记物；⑤发现PD患者的前额叶皮质、岛叶和视觉处理区调控小脑-丘脑-皮质运动环路的默认网络；⑥证实LAG3基因变异影响DA神经元功能，是PD的免疫重要相关基因。该基因在DA神经元及胶质细胞表达，介导了α-synuclein细胞间传递，可能是PD病程发展评估的潜在的生物学标记。