PDF(Pubmed)
Abstract：
Genetic tools to target microglia specifically and efficiently from the early stages of embryonic development are lacking. We generated a constitutive Cre line controlled by the microglia signature gene Crybb1 that produced nearly complete recombination in embryonic brain macrophages (microglia and border-associated macrophages [BAMs]) by the perinatal period, with limited recombination in peripheral myeloid cells. Using this tool in combination with Flt3-Cre lineage tracer, single-cell RNA-sequencing analysis, and confocal imaging, we resolved embryonic-derived versus monocyte-derived BAMs in the mouse cortex. Deletion of the transcription factor SMAD4 in microglia and embryonic-derived BAMs using Crybb1-Cre caused a developmental arrest of microglia, which instead acquired a BAM specification signature. By contrast, the development of genuine BAMs remained unaffected. Our results reveal that SMAD4 drives a transcriptional and epigenetic program that is indispensable for the commitment of brain macrophages to the microglia fate and highlight Crybb1-Cre as a tool for targeting embryonic brain macrophages.
摘要：
缺乏从胚胎发育的早期阶段特异性和有效地靶向小胶质细胞的遗传工具。我们产生了由小胶质细胞签名基因Cryb1控制的组成型Cre系，该基因在围产期在胚胎脑巨噬细胞（小胶质细胞和边界相关巨噬细胞[BAMs]）中产生了几乎完全的重组，在外周骨髓细胞中有限的重组。使用这个工具结合Flt3-Cre谱系示踪剂，单细胞RNA测序分析，和共聚焦成像，我们解决了小鼠皮质中胚胎来源的BAMs与单核细胞来源的BAMs。使用Crybb1-Cre缺失小胶质细胞和胚胎衍生的BAM中的转录因子SMAD4导致小胶质细胞的发育停滞，而是获得了BAM规范签名。相比之下,真正的BAMs的发展未受影响。我们的结果表明，SMAD4驱动一个转录和表观遗传程序，这对于脑巨噬细胞对小胶质细胞命运的承诺是必不可少的，并强调Crybb1-Cre是靶向胚胎脑巨噬细胞的工具。
