Table_4_Validation of Induced Microglia-Like Cells (iMG Cells) for Future Studies of Brain Diseases.xlsx

Microglia are the primary resident immune cells of the central nervous system that maintain physiological homeostasis in the brain and contribute to the pathogenesis of many psychiatric disorders and neurodegenerative diseases. Due to the lack of appropriate human cellular models, it is difficult to study the basic pathophysiological processes linking microglia to brain diseases. In this study, we adopted a microglia-like cellular model derived from peripheral blood monocytes with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-34 (IL-34). We characterized and validated this in vitro cellular model by morphology, immunocytochemistry, gene expression profiles, and functional study. Our results indicated that the iMG cells developed typical microglial ramified morphology, expressed microglial specific surface markers (P2RY12 and TMEM119), and possessed phagocytic activity. Principal component analyses and multidimensional scaling analyses of RNA-seq data showed that iMG cells were distinct from monocytes and induced macrophages (iMacs) but clustered closer to human microglia and hiPSC-induced microglia. Heatmap analyses also found that iMG cells, but not monocytes, were closely clustered with human primary microglia. Further pathway and relative expression analysis indicated that unique genes from iMG cells were involved in the regulation of the complement system, especially in the synapse and ion transport. Overall, our data demonstrated that the iMG model mimicked many features of the brain resident microglia, highlighting its utility in the study of microglial function in many brain diseases, such as schizophrenia and Alzheimer's disease (AD).

小胶质细胞（Microglia）是中枢神经系统的主要驻留免疫细胞，可维持大脑的生理稳态，同时参与多种精神疾病与神经退行性疾病的发病机制。由于缺乏适配的人类细胞模型，探究连接小胶质细胞与脑部疾病的基础病理生理过程存在较大难度。本研究采用了由外周血单核细胞经粒细胞-巨噬细胞集落刺激因子（GM-CSF）与白细胞介素34（IL-34）诱导构建的类小胶质细胞模型。研究团队通过形态学观察、免疫细胞化学检测、基因表达谱分析与功能实验，对该体外细胞模型进行了系统表征与验证。结果显示，诱导型小胶质细胞（iMG）呈现出典型的小胶质细胞分枝状形态，表达小胶质细胞特异性表面标志物P2RY12与TMEM119，且具备吞噬活性。对RNA测序（RNA-seq）数据的主成分分析与多维缩放分析表明，iMG细胞与单核细胞及诱导型巨噬细胞（iMacs）存在显著差异，却与人类原代小胶质细胞及hiPSC诱导的小胶质细胞聚类关系更为紧密。热图分析进一步证实，iMG细胞（而非单核细胞）与人类原代小胶质细胞聚类高度相似。后续的通路分析与相对表达量研究显示，iMG细胞的特异性基因参与补体系统的调控，尤其在突触稳态与离子转运过程中发挥关键作用。综上，本研究数据表明，iMG模型能够模拟大脑驻留小胶质细胞的诸多核心特征，凸显了其在探究小胶质细胞功能相关脑部疾病（如精神分裂症与阿尔茨海默病（AD））中的应用价值。