Table 1_Single-cell transcriptomic profiling reveals a novel signature of necrotizing granulomatous lesions in the lungs of Mycobacterium tuberculosis-infected C3HeB/FeJ mice.xlsx

Tuberculosis (TB) pathology involves complex immune responses within granulomatous lesions. Using single-cell RNA sequencing, we characterized the cellular compositions of necrotizing granulomatous lesions that developed in the lungs of Mycobacterium tuberculosis-infected C3HeB/FeJ mice. We identified 11 distinct major cell types, including phagocytes such as neutrophils and macrophages, and T cells, natural killer cells, B cells, dendritic cells, and plasmacytoid dendritic cells. Among T cells, particularly, Pdcd1+ γδ T cells were detected in necrotizing granulomatous lesions, suggesting their potential role in the pathogenicity of M. tuberculosis. Within the macrophage populations, we identified a cluster with significantly higher Plin2 expression compared to other clusters, whose transcriptomic profile was consistent with that of foamy macrophages. A subset of the Plin2-expressing macrophages was identified as a major source of Ifnb1 and Cxcl1, suggesting their involvement in type I interferon signaling and neutrophil recruitment. Furthermore, we identified Flrt2, Hyal1, and Mmp13 as novel molecular markers of Plin2-expressing macrophages, which were localized to the peripheral rim regions of necrotizing granulomas. In conclusion, our results provide the immune landscape of necrotizing granulomas and reveal novel functional states of macrophages contributing to TB pathogenesis.

结核病（Tuberculosis, TB）的病理过程涉及肉芽肿性病变（granulomatous lesions）内复杂的免疫应答。本研究采用单细胞RNA测序（single-cell RNA sequencing）技术，对感染结核分枝杆菌（Mycobacterium tuberculosis）的C3HeB/FeJ小鼠肺部形成的坏死性肉芽肿性病变（necrotizing granulomatous lesions）的细胞组成特征进行了系统解析。我们共鉴定出11种不同的主要细胞类群，包括中性粒细胞（neutrophils）、巨噬细胞（macrophages）等吞噬细胞（phagocytes），以及T细胞（T cells）、自然杀伤细胞（natural killer cells）、B细胞（B cells）、树突状细胞（dendritic cells）与浆细胞样树突状细胞（plasmacytoid dendritic cells）。尤为值得注意的是，本研究在坏死性肉芽肿性病变中检测到了Pdcd1阳性γδ T细胞（Pdcd1+ γδ T cells），提示该类细胞可能参与结核分枝杆菌的致病过程。在巨噬细胞类群中，我们鉴定出一个相较于其他细胞聚类显著高表达Plin2的细胞簇，其转录组特征与泡沫样巨噬细胞（foamy macrophages）高度一致。进一步研究发现，该表达Plin2的巨噬细胞亚群是Ifnb1与Cxcl1的主要来源，表明其参与I型干扰素信号通路（type I interferon signaling）调控与中性粒细胞招募（neutrophil recruitment）过程。此外，本研究还鉴定出Flrt2、Hyal1与Mmp13作为表达Plin2的巨噬细胞的新型分子标记物，这些标记物定位于坏死性肉芽肿（necrotizing granulomas）的外周边缘区域。综上，本研究结果描绘了坏死性肉芽肿的免疫景观，并阐明了参与结核病发病机制的巨噬细胞的新型功能状态。