Translocator protein (18 kDa) regulates the microglial phenotype in Parkinson’s disease through P47

Numerous studies have suggested that the phenotypic transformation of microglia plays a role in the pathogenesis of Parkinson’s disease (PD). Translocator protein (TSPO) is an 18 kDa translocator membrane protein that acts as a marker of neuroinflammation and suppresses neuroinflammation; however, its underlying mechanism remains unclear. Although TSPO ligands were found to be protective in several neurodegenerative paradigms, few studies have evaluated their effects on microglial polarization, and underlying mechanisms need to be explored. In the present study, we examined the effects of TSPO and PK11195, a TSPO ligand, on lipopolysaccharide (LPS)+interferon (IFN)-γ-induced inflammatory factors and oxidative stress in microglia using enzyme-linked immunosorbent assay. The effect of TSPO and PK11195 on LPS+IFN-γ-induced microglial cell apoptosis was examined using immunofluorescence (IF), flow cytometry, and western blotting. The interaction between TSPO and P47 was investigated using IF and co-immunoprecipitation analysis. In vivo experiments confirmed the influence of TSPO and its ligand on motility, a-Syn, and dopaminergic neuronal damage. Our findings indicate that TSPO may regulate the microglial phenotype in PD via P47, suggesting a potential role in anti-PD therapy.

多项研究表明，小胶质细胞的表型转化在帕金森病（Parkinson’s disease, PD）的发病机制中发挥着重要作用。转位蛋白（Translocator protein, TSPO）是一种分子量为18 kDa的转位膜蛋白，可作为神经炎症标志物并参与调控神经炎症，但其具体潜在分子机制仍未明确。尽管已有研究证实转位蛋白配体在多种神经退行性疾病模型中具有保护作用，但目前鲜有研究评估其对小胶质细胞极化的影响，相关潜在机制尚待进一步探索。
本研究采用酶联免疫吸附测定（enzyme-linked immunosorbent assay），检测了转位蛋白及其特异性配体PK11195对脂多糖（lipopolysaccharide, LPS）联合干扰素（interferon, IFN）-γ诱导的小胶质细胞炎症因子表达与氧化应激水平的影响；通过免疫荧光（immunofluorescence, IF）、流式细胞术及蛋白质印迹（western blotting）实验，分析了二者对LPS+IFN-γ诱导的小胶质细胞凋亡的调控作用。
本研究还借助免疫荧光与免疫共沉淀（co-immunoprecipitation）技术，探究了转位蛋白与P47蛋白的相互作用关系。体内实验则验证了转位蛋白及其配体对运动能力、α-突触核蛋白（α-Syn）表达及多巴胺能神经元损伤的影响。
本研究结果显示，转位蛋白可能通过调控P47蛋白参与帕金森病中小胶质细胞的表型转化过程，这为抗帕金森病治疗提供了潜在的新靶点与新思路。