Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China.
Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, China.
CNS Neurosci Ther. 2024 Oct;30(10):e70088. doi: 10.1111/cns.70088.
Parkinson's disease (PD) is characterized by the formation of Lewy bodies (LBs), primarily constituted of α-synuclein (α-Syn). Microglial cells exhibit specific reactivity toward misfolded proteins such as α-Syn. However, the exact clearance mechanism and related molecular targets remain elusive.
BV2 cells, primary microglia from wild-type and MT1 knockout mice, and primary cortical neurons were utilized as experimental models. The study investigated relevant mechanisms by modulating microglial MT1 expression through small RNA interference (RNAi) and lentiviral overexpression techniques. Furthermore, pathological aggregation of α-Syn was induced using pre-formed fibrils (PFF) α-Syn. Co-immunoprecipitation, immunofluorescence, Western blot (WB), and quantitative real-time PCR were used to elucidate the mechanisms of molecular regulation.
In this study, we elucidated the regulatory role of the melatonin receptor 1 (MT1) in the microglial phagocytic process. Following MT1 knockout, the ability of microglial cells to engulf latex beads and zymosan particles decreased, subsequently affecting the phagocytic degradation of fibrillar α-Syn by microglial cells. Furthermore, the loss of MT1 receptors in microglial cells exacerbates the aggregation of α-Syn in neurons induced by pre-formed fibrils (PFF) α-Syn. Mechanistically, MT1 influences the phagocytic function of microglial cells by regulating the Rubicon-dependent LC3-associated phagocytosis (LAP) pathway.
Taken together, the results suggest the neuroprotective function of microglial cells in clearing α-Syn through MT1-mediated LAP, highlighting the potential key role of MT1 in pathogenic mechanisms associated with α-Syn.
帕金森病（PD）的特征是Lewy 体（LB）的形成，主要由α-突触核蛋白（α-Syn）组成。小胶质细胞对错误折叠的蛋白质如α-Syn 表现出特异性反应。然而，确切的清除机制和相关的分子靶点仍然难以捉摸。
BV2 细胞、野生型和 MT1 敲除小鼠的原代小胶质细胞以及原代皮质神经元被用作实验模型。通过小 RNA 干扰（RNAi）和慢病毒过表达技术调节小胶质细胞 MT1 表达，研究了相关机制。此外，使用预形成纤维（PFF）α-Syn 诱导α-Syn 的病理性聚集。共免疫沉淀、免疫荧光、Western blot（WB）和实时定量 PCR 用于阐明分子调节的机制。
在这项研究中，我们阐明了褪黑素受体 1（MT1）在小胶质细胞吞噬过程中的调节作用。在 MT1 敲除后，小胶质细胞吞噬乳胶珠和酵母聚糖颗粒的能力下降，随后影响小胶质细胞对纤维状α-Syn 的吞噬降解。此外，小胶质细胞中 MT1 受体的缺失加剧了预形成纤维（PFF）α-Syn 诱导的神经元中α-Syn 的聚集。从机制上讲，MT1 通过调节 Rubicon 依赖性 LC3 相关吞噬（LAP）途径影响小胶质细胞的吞噬功能。
综上所述，这些结果表明，小胶质细胞通过 MT1 介导的 LAP 清除α-Syn 具有神经保护功能，突出了 MT1 在与α-Syn 相关的致病机制中的潜在关键作用。
