Inducible CCR2+ nonclassical monocytes mediate the regression of cancer metastasis

Classical monocytes (CMs) can be converted into conventional dominant Nr4a1-dependent nonclassical monocytes (N-NCMs). Upon activation of Nod2 signaling, CM also can be converted into noncanonical Nod2-dependent inducible NCMs (I-NCMs). The transcriptional profiles and typical markers specific for those two NCM subsets yet to be determined. To transcriptionally characterize N-NCM and I-NCM, we performed transcriptional profiling analysis using RNAseq data obtained from the flow-sorted NCM subsets. Through the comprehensive RNAseq analysis, we identified typical transcriptional markers specific to N-NCM and I-NCM. By virtue of those specific markers, we identified the potential I-NCM populations in multiple cellular settings. Overall design: To purely collect N-NCM and I-NCM, we sorted the blood NCMs from MDP-treated Nod2KO mice and Nr4a1KO mice, respectively. The flow-sorted NCMs were used for bulk RNA sequencing.

经典单核细胞（Classical monocytes, CMs）可转化为常规显性Nr4a1依赖型非经典单核细胞（N-NCMs）。当Nod2信号通路激活时，经典单核细胞还可转化为非经典型Nod2依赖型诱导性非经典单核细胞（I-NCMs）。目前这两类非经典单核细胞亚群的转录特征与特异性标志物仍有待明确。为从转录层面表征N-NCM与I-NCM，本研究采用流式分选获得的非经典单核细胞亚群的RNA测序（RNAseq）数据开展转录组分析。通过全面的RNAseq分析，本研究鉴定出了N-NCM与I-NCM各自特异性的转录标志物。依托这些特异性标志物，本研究在多种细胞环境中鉴定出了潜在的I-NCM群体。实验整体设计：为精准分离N-NCM与I-NCM，本研究分别从经MDP处理的Nod2基因敲除（Nod2KO）小鼠与Nr4a1基因敲除（Nr4a1KO）小鼠中分选血液非经典单核细胞，将流式分选得到的非经典单核细胞用于批量RNA测序（bulk RNA sequencing）。