Spatial distribution and chromatin accessibility determine the therapeutic capacity of microglial subsets during neurodegeneration [ATAC-seq]

Microglial spatial heterogeneity remains a crucial yet poorly studied question in light of potential cell-directed therapies for Alzheimer`s disease (AD). Little is known about the dynamics of spatially distinct microglia states, which are either adjacent or non-associated with the plaque site, and their selective contributions to neurodegeneration in vivo. So far, research has essentially focused on pathology-associated microglia. Here, we combined novel multicolour fluorescence fate mapping, single-cell transcriptional analysis, epigenetic profiling, advanced immunohistochemistry and computational modelling to comprehensively characterize the relation of plaque-associated and non-plaque-associated microglia during neurodegeneration in female mice. This approach enabled us to identify and characterize non-plaque-associated microglia as a unique and highly dynamic microglial state in a mouse model of AD. Non-plaque-associated microglia modulate network expansion, quickly adapt to environmental cues and their transition to plaque-associated microglia can be specifically modulated during disease, contrary to their reputation as a passive bystander subpopulation. This description of the dynamics of spatially segregated microglial states and their distinct molecular features may therefore open promising new avenues for state-specific therapeutic interventions during neurodegeneration. Following either colony stimulating factor 1 (Csf1) or PBS (control) treatment, CD11c positive and negative microglia from early stage (ES) 5xFAD positive and negative mice were sorted by fluorescence-activated cell sorting (FACS) and analyzed by ATACseq.

鉴于阿尔茨海默病（Alzheimer's Disease, AD）靶向细胞治疗的潜在前景，小胶质细胞的空间异质性仍是一个关键却尚未得到充分研究的科学问题。目前对于与斑块位点相邻或非关联的空间特异性小胶质细胞状态的动态变化，及其在体内对神经退行性过程的选择性调控作用，仍知之甚少。迄今为止，相关研究大多聚焦于病理相关小胶质细胞。本研究结合新型多色荧光命运图谱技术、单细胞转录组分析、表观遗传谱分析、先进免疫组织化学技术与计算建模方法，对雌性小鼠神经退行性变过程中斑块相关与非斑块相关小胶质细胞的关联特征进行全面解析。通过该研究方案，我们成功鉴定并解析出非斑块相关小胶质细胞作为AD小鼠模型中一种独特且高度动态的小胶质细胞状态。与此前将其视为被动旁观者亚群的认知不同，非斑块相关小胶质细胞可调控病理网络扩增，快速响应环境信号，且其向斑块相关小胶质细胞的转化可在疾病进程中被特异性调控。因此，对空间分隔的小胶质细胞状态动态变化及其独特分子特征的解析，有望为神经退行性变阶段的状态特异性治疗干预开辟全新的前景方向。在分别接受集落刺激因子1（Colony Stimulating Factor 1, Csf1）或磷酸盐缓冲液（PBS，对照组）处理后，研究人员通过荧光激活细胞分选术（Fluorescence-Activated Cell Sorting, FACS）分离了早期阶段（ES）5xFAD阳性及阴性小鼠体内CD11c阳性和阴性的小胶质细胞，并通过转座酶可及性染色质测序（ATAC-seq）对其进行分析。