Supplementary Material for: The Gene Signature of Activated M-CSF-Primed Human Monocyte-Derived Macrophages Is IL-10-Dependent

During inflammatory responses, monocytes are recruited into inflamed tissues, where they become monocyte-derived macrophages and acquire pro-inflammatory and tissue-damaging effects in response to the surrounding environment. In fact, monocyte-derived macrophage subsets are major pathogenic cells in inflammatory pathologies. Strikingly, the transcriptome of pathogenic monocyte-derived macrophage subsets resembles the gene profile of macrophage colony-stimulating factor (M-CSF)-primed monocyte-derived human macrophages (M-MØ). As M-MØ display a characteristic cytokine profile after activation (IL10^high TNF^low IL23^low IL6^low), we sought to determine the transcriptional signature of M-MØ upon exposure to pathogenic stimuli. Activation of M-MØ led to the acquisition of a distinctive transcriptional profile characterized by the induction of a group of genes (Gene set 1) highly expressed by pathogenic monocyte-derived macrophages in COVID-19 and whose presence in tumor-associated macrophages (TAM) correlates with the expression of macrophage-specific markers (<i>CD163</i>, <i>SPI1</i>) and <i>IL10</i>. Indeed, Gene set 1 expression was primarily dependent on ERK/p38 and STAT3 activation, and transcriptional analysis and neutralization experiments revealed that IL-10 is not only required for the expression of a subset of genes within Gene set 1 but also significantly contributes to the idiosyncratic gene signature of activated M-MØ. Our results indicate that activation of M-CSF-dependent monocyte-derived macrophages induces a distinctive gene expression profile, which is partially dependent on IL-10, and identifies a gene set potentially helpful for macrophage-centered therapeutic strategies.

在炎症应答过程中，单核细胞（monocytes）被招募至炎症组织（inflamed tissues），在此处分化为单核细胞衍生巨噬细胞（monocyte-derived macrophages），并响应周围微环境获得促炎及组织损伤功能。实际上，单核细胞衍生巨噬细胞亚群是炎症性疾病的主要致病细胞群。值得注意的是，致病单核细胞衍生巨噬细胞亚群的转录组（transcriptome）与经巨噬细胞集落刺激因子（macrophage colony-stimulating factor, M-CSF）诱导的人单核细胞衍生巨噬细胞（M-MØ）的基因谱（gene profile）高度相似。由于M-MØ在激活后呈现特征性细胞因子谱（cytokine profile）（IL10高表达、TNF低表达、IL23低表达、IL6低表达），本研究旨在探究M-MØ暴露于致病刺激物（pathogenic stimuli）时的转录特征（transcriptional signature）。激活M-MØ可使其获得独特的转录谱（transcriptional profile），该特征以一组基因（基因集1，Gene set 1）的诱导表达为标志：这类基因在新型冠状病毒肺炎（COVID-19）患者的致病单核细胞衍生巨噬细胞中高表达，且其在肿瘤相关巨噬细胞（tumor-associated macrophages, TAM）中的表达与巨噬细胞特异性标志物（macrophage-specific markers，CD163、SPI1）及IL10的表达呈正相关。进一步研究发现，基因集1的表达主要依赖于细胞外调节蛋白激酶/ p38丝裂原活化蛋白激酶（ERK/p38）及信号转导和转录激活因子3（STAT3）的激活；转录组分析与中和实验（neutralization experiments）结果表明，IL-10不仅是基因集1中部分基因表达所必需的，还显著参与塑造激活后M-MØ的独特基因特征（idiosyncratic gene signature）。本研究结果显示，依赖巨噬细胞集落刺激因子（M-CSF）的单核细胞衍生巨噬细胞的激活可诱导产生独特的基因表达谱，该过程部分依赖于IL-10的调控；同时，本研究鉴定出的基因集有望为以巨噬细胞为中心的治疗策略（therapeutic strategies）提供潜在帮助。