外泌体非编码RNAs在SCA3/MJD发病机制中的作用研究

Spinocerebellar ataxia type 3/Machado-Joseph disease (SCA3/MJD) is a kind of clinical and genetic heterogeneous neurodegenerative disorder with high mortality and disability. Till now, its pathogenesis has not been fully elucidated, and therefore has no effective therapy. Recently, as an attractive medium of intercellular communication, exosome provides a new insight to explore the pathogenesis and treatment of SCA3/MJD. We previously probed differentially expressed miRNAs in the peripheral serum and CSF exosomes of SCA3/MJD patients, and verified their preliminary function in the transgenic cell models, as well as differentially expressed mRNA and lncRNAs in the transgenic mouse models. In this study, we intend to validate the differentially expressed proteins and noncoding RNAs in the CSF and brain tissues of a larger SCA3/MJD cohort, to pursue the potential biomarker as valuation of the phenotype and disease progression, to analyze the roles of exosome noncoding RNAs in the pathogenesis of SCA3/MJD and to investigate the potential therapeutic effects of exosomes in the transgenic cells and mice. The study will provide a new clue to elucidate the pathogenesis and therapy prospect of SCA3/MJD.

遗传性脊髓小脑型共济失调3型/马查多-约瑟夫病（SCA3/MJD）是一种具有高度临床和遗传异质性、致死率和致残率高的神经退行性疾病，其发病机制尚未完全阐明，目前尚无有效治疗方法。外泌体作为备受关注的细胞间通讯媒介，为探讨该病的发病机制及治疗提供了新方向。在前期工作中，我们在SCA3/MJD患者外周血及脑脊液外泌体中发现了差异性表达的miRNAs，并在转基因细胞模型中进行了初步功能验证；在转基因小鼠模型脑组织中发现了差异性表达的mRNA和lncRNAs。本研究拟扩大SCA3/MJD患者样本量以进一步筛选并验证脑脊液及脑组织外泌体中差异性表达的蛋白质及非编码RNAs，寻找可用于评估临床表型和疾病进展的生物标志物；在转基因细胞模型和小鼠模型中探讨外泌体非编码RNAs在发病机制中的作用以及外泌体在该病治疗中的潜在价值。本研究为进一步阐明SCA3/MJD的发病机制提供新思路，为该病的治疗提供新线索。

遗传性脊髓小脑型共济失调3型/马查多-约瑟夫病（SCA3/MJD）是一种具有高度临床和遗传异质性、致死率和致残率高的神经退行性疾病，其发病机制尚未完全阐明，目前尚无有效治疗方法；而外泌体作为细胞间通讯媒介，为探讨该病的发病机制及治疗提供了新方向。. 本项目首次筛选并验证了SCA3/MJD患者及正常对照的外周血血浆及脑脊液来源外泌体中差异性表达的miRNAs，发现了novel-mir-7014在SCA3/MJD患者血浆来源外泌体中表达下调，在患者脑脊液来源外泌体中表达上调，提示外泌体novel-mir-7014可作为SCA3/MJD早期诊断的潜在生物标志物，且可能与SCA3/MJD的发病机制有关。进一步发现，外泌体novel-mir-7014表达水平与SCA3/MJD患者的年龄、病程、SARA评分、CAG重复序列拷贝数等相关性尚不显著。功能研究提示novel-mir-7014主要通过内质网蛋白加工通路参与SCA3/MJD发病机制，可通过下调novel-mir-7014降低突变型ataxin-3蛋白的表达水平和细胞毒性，发挥潜在的治疗作用。. 同时，本项目首次筛选并验证了SCA3/MJD转基因小鼠与野生型小鼠小脑组织细胞外间隙来源外泌体中miRNAs的差异表达谱及差异表达miRNAs在疾病不同年龄的变化，发现脑组织细胞外间隙外泌体中mmu-miR-669a-3p及mmu-miR-690的表达在SCA3/MJD转基因小鼠中随病程延长呈下降趋势。mmu-miR-690与在SCA3/MJD转基因小鼠小脑组织中差异表达的lncRNA NONMMUT008477.2存在结合位点，可能均为SCA3/MJD分子调控网络中的重要组分，为SCA3/MJD的发病机制提供新证据。. 综上，本项目将为SCA3/MJD等polyQ病的早期诊断、治疗和发病机制研究提供坚实的科学依据，有重要的临床应用前景。