大麻素受体CB2作为帕金森病治疗新靶点的作用及其分子机制研究

Parkinson's disease (PD) is a neurodegenerative disease with the loss of dopaminergic neurons and the form of Louis body. Till now the effective drugs that capable controlling the disease progress is still lacking. Cannabinoid receptors distribute in the central nervous system, meanwhile, cannabinoid receptors 2 was found down-regulated in substantia nigra of PD patients and animal models. Our previous studies showed that the specific CB2 receptor agonist AM1241 can improve the motor function of PD mice, and enhance the midbrain dopamine neurotransmitter level. On the contrary, its inhibitor BML190 can induce mouse PD like symptoms, suggesting that CB2 receptor might be a new target for PD therapy. This project intends to carry out three aspects of research: (1) through the knockout / overexpression of CB1 and CB2 receptor, analyze the target effect of CB2 receptor; (2) by immunofluorescence detection, determine the specific target cells of AM1241 activation, and clarify the biological function of DA neurons, astrocytes and microglia under AM1241 treatment; 3) by means of Western blot assay, explore the signaling pathways involved in the neuroprotection effect of AM1241. With the process of the project, we can determine the target effect and the mechanisms of CB2 receptor for PD treatment, which can provide a new target and novel theoretical basis for PD therapy.

帕金森病（PD）是以多巴胺能神经元丢失和路易小体形成为特征的神经退行性疾病，目前尚缺乏有效控制病情进展的药物。大麻素受体分布于中枢神经系统，在PD患者及动物模型中均发现黑质区CB2受体表达下调。我们的前期研究表明，CB2受体的特异性激动剂AM1241能够改善PD模型小鼠的运动功能，提升中脑区域多巴胺神经递质水平；其拮抗剂BML190则会诱发小鼠PD样症状，提示CB2受体极有可能成为干预PD的新靶点。本课题拟开展三方面研究：1）通过敲除/过表达CB1、CB2受体，分析CB2靶点作用；2）通过免疫荧光等技术，分析AM1241激活CB2受体的具体靶细胞，阐明DA神经元、星形胶质和小胶质细胞在AM1241作用下的生物学功能；3）通过免疫共沉淀等手段，分析AM1241保护多巴胺能神经元的分子机制。通过课题的实施，确证CB2受体是PD治疗的靶点，阐明其干预PD的机制，为PD治疗提供新靶点和理论指导。

帕金森病（PD）是以多巴胺能神经元丢失和路易小体形成为特征的神经退行性疾病，目前尚缺乏有效控制病情进展的药物。内源性大麻素系统与PD发生、发展密切相关，针对其开展的替代药物和作用机制研究对于探索PD治疗新靶点和新方法具有重要意义。通过课题的开展，成功构建了WT，CB1，CB2 基因敲除的PD模型小鼠，研究了AM1241在各组的治疗效果。结果显示AM1241能够有效治疗WT和CB1-KO的PD小鼠症状。而不能有效改善CB2-KO的PD小鼠症状。RNA-seq分析确定Xist发挥重要调节作用。AM1241处理能够维持WT和CB1-KO小鼠Xist以及Xist下游的miR-133b-3p和Pitx3的正常表达。体外过表达Xist或AM1241处理能够保护6-OHDA引起的细胞死亡和Pitx3的表达增加。机制研究证实AM1241治疗PD是通过调节Xist/miR-133b-3p/Pitx3通路，为帕金森病的治疗提供了新方法。