α-突触核蛋白异常沉积致小鼠RBD/帕金森病的作用、通路机制及海藻糖干预

REM sleep behavior disorders (RBD) is the most specific non-motor symptoms predicting the development of parkinsonism, including idiopathic Parkinson’s disease(iPD), multiple system atrophy (MSA), and Diffuse Lewy body dementia(DLB), which share a common pathological feature of α-synuclein aggregation (α-synucleinopathy). Most of the patients with idiopathic RBD(iRBD) will eventually develop a certain type of parkinsonism after long term longitudinal follow-up, therefore, it will be extremely important for neurologists to take advantage of this critical period of premotor stage to facilitate earlier diagnosis and apply disease-modifying therapy for PD. However, there is no animal model of RBD with α-synucleinopathy available so far, which is a key limitation to move forward the conception of “earlier diagnosis and better intervention for PD”. In the current research, we will inject AAV9 overexpressing A53T-α-synuclein in a stereotactic manner into sublaterodorsal tegmental nucleus(SLD) of C57BL6 mice, to validate RBD mice model by analyzing behavior test, immunohistochemical staining, HPLC for assaying neurotransmitters, immunoblotting etc. Furthermore, we will utilize the strategy of optogenetics by injecting AAV9-GAD2-ChR2 in SLD in Vglut2-cre C57BL6 mice, to explore the underlying pathway from SLD to gigantocellular reticular nucleus ventral part (GiV) in the mechanism of RBD. Also, we will investigate the spreading of α-synuclein aggregation in C57BL6 mice RBD model induced by stereotactic injection of AAV9 overexpressing A53T-α-synuclein into SLD, track the spatial and temporal pattern of α-synuclein propagation during the development of PD from RBD, and analyze the correlation of α-synuclein spreading with motor and nonmotor symptoms of PD. Finally, we will treat the RBD mice model induced by AAV9-A53T-α-Synuclein with trehalose, to explore its effectiveness, timing of intervention, and underlying mechanism by testing the behavior change of the model, the level of neurontransmitters, α-synuclein deposition, and in vivo sequentially imaging dopamine transporter and activated microglia on MicroPET. Promisingly, the implementation of current program would substantially deepen our understanding of pathogenesis of RBD and subsequent conversion to PD, facilitate the advance of early diagnosis of PD at its premotor stage, and potentially provide novel strategy of the intervention for RBD/PD in the future.

快动眼期睡眠行为障碍（RBD）是预警帕金森病(PD)的最特异非运动症状，其病理基础是脑中α-突触核蛋白（α-syn）异常聚集，迄今尚无有此病理改变的RBD小动物模型。本研究通过过表达A53T-α-syn的AAV9病毒经立体定向注射至C57BL6小鼠桥脑背外侧核下部（SLD），行为学、病理、递质、免疫印迹检测等多角度验证模型；应用光遗传技术在谷氨酸-Cre转基因小鼠SLD核谷氨酸能细胞中过表达兴奋性光敏感蛋白，探讨RBD发生的SLD至GiV核的通路机制；RBD模型转化为PD过程中α-syn病理播散的时空贯序及与PD运动/非运动障碍的关联;海藻糖干预后分析脑α-Syn病理、递质、行为学、小动物PET脑多巴胺转运体和炎性指标等,探讨其阻断RBD模型的发生及向PD转化的干预作用、时机及机制。本项目将有助于加深对RBD/PD病因和发病机制的理解,为PD早诊早治新策略提供重要的实验依据。

快动眼期睡眠行为障碍（RBD）是帕金森病早期的非运动症状，可早于帕金森运动症状10年前出现，因此RBD对帕金森病具有重要的早期预警和干预意义。在现有文献证据的支持下，本研究聚焦于脑桥REM睡眠调控环路通过向脑桥被盖背外侧下核（SLD）立体定向注射预制纤维体（PFFs）构建具备突触核蛋白病理特征的RBD动物模型。持续的随访研究表明具备RBD表型的动物可缓慢进展并最终转归出现帕金森运动和非运动表型，伴随全脑弥漫播散的ɑ突触核蛋白病理改变。此外，具备突触核蛋白病理特征的帕金森动物接受海藻糖干预后呈现运动障碍症状减轻、黑质多巴胺能神经元存活数目增多、黑质纹状体系统病理沉积减少的行为及病理表型。进一步深入的研究揭示海藻糖可通过上调自噬通路活性促进病理性突触核蛋白降解从而发挥神经保护作用。该研究将有助于加深我们对RBD发生及其向帕金森转归的病理生理机制的理解，为未来开发帕金森病的病程修饰策略提供重要的基础实验证据支持。