外侧缰自噬-溶酶体途径调控GABAA受体在帕金森病相关抑郁中的作用及机制研究

约50%帕金森病患者存在帕金森病相关抑郁（PDD）症状，其发病机制尚不清楚。本课题组前期发现外侧缰（LHb）内注射GABAA受体激动剂可改善PDD模型抑郁样行为；同时上调LHb中自噬水平也可缓解抑郁样行为。基于此，我们推测LHb内自噬-溶酶体途径（ALP）异常导致GABAA受体表达、功能下调与PDD发生发展相关。为了探究ALP调控GABA系统在PDD中的作用及机制，我们拟采用基因工程小鼠及神经元PDD模型，采用免疫荧光组织/细胞化学、免疫电镜、分子生物学、在体/脑片电生理、神经化学检测并结合小鼠行为学进行研究：1、探究LHb中ALP调控GABAA受体表达或功能在PDD中的作用；2、明确PDD模型LHb中ALP调节GABAA受体膜转运和降解过程的机制；3、证实ALP关键分子与PDD患者抑郁程度、临床分期的相关性。本项目将ALP引入PDD研究领域，为其发病机制研究、临床诊治提供新思路。

Parkinson’s disease-associated depression (PDD) is a common non-motor symptom in Parkinson’s disease (PD) patients, which seriously affects the prognosis of PD, but the cause of PDD remains largely unknown. The lateral habenula (LHb) plays an important role in the regulation of depression and increasing evidence indicates that the LHb plays a key role in antidepressant treatment. Although based on our previous research, intra-LHb injection of GABAA receptor agonist muscimol produced antidepressant-like effects in PDD models, but the mechanism of the dysregulation of GABAA receptors expression and reduction of GABA release in the LHb were unclear yet. And we also find that regulation of autophagy levels in LHb could alleviate depression-like behaviors. Base on above, we want to make a hypothesis that autophagy-lysosome pathway (ALP) abnormality leads to the downregulation of GABA system function (especially in GABAA receptor expression) in LHb which involved in the pathology of PDD. By using the PDD mouse models, we will firstly detect the levels and function of ALP. Then, we will investigate the coordinate effect and its mechanism by up or down regulating ALP key factors functions (as Atg5, Lamp2a, and CTSD) by using transgenic mouse and lentivirus. In PDD mouse models and LHb brain slices interfered by over expression or down regulation of GABARAPs via lentivirus or interfering peptide, we will detect the GABA/monoamines levels in LHb, striatum, medial prefrontal cortex, hippocampus and amygdala by microdialysis and neurochemistry; analyze the GABAA receptors expression by Western blotting and immunohistochemistry; evaluate the changes of neurons firing activity and GABA release in LHb by electrophysiological recording; test the PDD rats behavior included open field test, sucrose preference test and forced swim test. Finally, we will approve the expression of Atg5, Lamp2a, CTSD and GABARAPs in white blood cells samples of PDD patients combined with clinical data. Our studies will identify ALP as the potent factor whose effectiveness relies on its ability to effectively regulate the GABA signals of LHb through the ALP- GABAA receptor pathway against depression-related behaviors in PDD. Collectedly, this study will help to identify the pathway included of ALP regulate the function of GABA signals in pathogenic mechanism of PDD, which is also a new therapeutic target or procedure for PDD therapy.