Murine GMP- and MDP-derived classical monocytes have distinct functions and fates [dataset 2]

Monocytes are short-lived myeloid immune cells that arise from adult hematopoiesis and circulate for a short time in the blood. They comprise two main subsets, in mice defined as classical Ly6Chigh and non-classical Ly6Clow monocytes (CM, NCM). Recent fate mapping and transcriptomic analyses revealed that CM themselves are heterogeneous. Here, we report surface markers that allow segregation of murine GMP- and MDP-derived CM in the BM and blood. Functional characterization, including fate definition following adoptive cell transfer, established that GMP-Mo and MDP-Mo could equal rise to homeostatic CM progeny, such as NCM in blood and gut macrophages, but differentially seeded selected other tissues. Specifically, GMP-Mo and MDP-Mo gave rise to distinct interstitial lung macrophages, thus linking CM dichotomy to previously reported pulmonary macrophage heterogeneity. Collectively, we provide comprehensive evidence for the existence of two functionally distinct CM subsets in the mouse, which differentially contribute to peripheral tissue macrophage populations in homeostasis and following challenge. Our findings are indicative of impact of monocyte ontogeny on in situ differentiation. Cells were sorted to purity and subjected to bulk RNAseq. These include classical monocytes from BM and blood defined either by fatemappers (DR samples) or defined by surface markers (others). Lung IM were derived from adoptively transferred monocytes or BM chimeras.

单核细胞是一类寿命较短的髓系免疫细胞，源自成体造血过程，并在血液中短暂循环。其主要包含两个亚群，在小鼠中被定义为经典型Ly6C高表达单核细胞（classical Ly6Chigh monocytes, CM）与非经典型Ly6C低表达单核细胞（non-classical Ly6Clow monocytes, NCM）。近期的命运图谱分析与转录组学研究显示，CM本身具有异质性。本研究报道了可用于分离骨髓（bone marrow, BM）与血液中小鼠来源粒细胞-巨噬细胞祖细胞（granulocyte-macrophage progenitor, GMP）及单核细胞-树突状细胞祖细胞（monocyte-dendritic cell progenitor, MDP）的CM的表面标志物。通过包括过继细胞转移后的命运鉴定在内的功能表征实验，证实源自GMP与MDP的CM可同等产生稳态状态下的CM子代细胞，例如血液中的NCM与肠道巨噬细胞，但二者可差异性定植于特定的其他组织。具体而言，源自GMP与MDP的CM可产生截然不同的肺间质巨噬细胞，从而将CM的二分性与此前报道的肺巨噬细胞异质性联系起来。综上，本研究为小鼠体内存在两个功能截然不同的CM亚群提供了全面证据，这些亚群在稳态及受刺激后可差异性贡献至外周组织巨噬细胞群体。我们的研究结果表明，单核细胞的发育起源对原位分化具有调控作用。实验中细胞被纯化分选并进行批量RNA测序（bulk RNAseq）。这些样本涵盖来自骨髓与血液的经典型单核细胞，其分选标准包括命运图谱标记（DR样本）或表面标志物（其余样本）。肺间质巨噬细胞（IM）源自过继转移的单核细胞或骨髓嵌合体（BM chimeras）。