Characterisation of young, old and old repopulating microglia in spinal cord and brain of C57BL/6 wild type male mice

To address whether, after depletion by Csf1r inhibition, microglia repopulating the CNS revert to a “younger” phenotype, we treated a group of 23 months old mice with the Csf1r inhibitor for 5 days and let microglia repopulate the central nervous system for 7 days. Young (3 months old) and old (23 months old) mice were included as controls. After the repopulation time, whole spinal cord samples and Fluorescence Activated Sorting (FACS)-sorted microglia cells from brain tissue were collected to perform bulk transcriptome (RNAseq) analysis. Analysis of whole spinal cord suggested that repopulating microglia tend to re-acquire its original aged phenotype. Gene expression in FACS-sorted microglia was then analyzed to better characterize its intrinsic phenotype after repopulation. In contrast to the whole spinal cord samples, old and old-treated replicates separated in Principal Component Analysis, suggesting that repopulating microglia displayed a different phenotype compared to old microglia. NGS based mRNA profiling of whole spinal cord and FACS-sorted microglia of young (3 months), old and old repopulating (23 months) samples. 8 replicates per group were used.

为探究经Csf1r抑制剂耗竭后的小胶质细胞重新定植中枢神经系统（CNS）后是否可恢复至“更年轻”的表型，本研究对23月龄小鼠给予Csf1r抑制剂处理5天，随后使小胶质细胞重新定植中枢神经系统7天。本研究设置3月龄年轻小鼠与23月龄老年小鼠作为对照组。定植周期结束后，我们收集全脊髓样本以及脑组织经荧光激活细胞分选（Fluorescence Activated Sorting, FACS）得到的小胶质细胞，开展批量转录组（RNAseq）分析。对全脊髓样本的分析结果显示，重新定植的小胶质细胞倾向于恢复其原本的衰老表型。随后我们对经FACS分选的小胶质细胞的基因表达谱进行分析，以更精准地表征其定植后的内在表型。与全脊髓样本的分析结果不同，主成分分析（PCA）中老年组与老年处理组的生物学重复样本出现分离，提示重新定植的小胶质细胞与原生老年小胶质细胞的表型存在差异。本数据集包含年轻（3月龄）、老年（23月龄）以及老年小鼠来源的经小胶质细胞重新定植（23月龄）样本的全脊髓和FACS分选小胶质细胞的二代测序（NGS）mRNA表达谱数据，每组设置8个生物学重复。