Single-cell analysis reveals Mycobacterium tuberculosis ESX-1–mediated accumulation of permissive macrophages in infected mouse lungs

Mycobacterium tuberculosis (MTB) infects and replicates in lung mononuclear phagocytes (MNPs) with astounding ability to evade elimination. A virulence determinant that contributes to MTB’s ability to survive within MNPs is ESX-1, a type VII secretion system. However, how MTB virulence factors influence mononuclear cell recruitment and/or differentiation remains unknown. Here, using single-cell RNA sequencing, we studied the role of ESX-1 in MNP heterogenicity and response in mice and murine bone marrow-derived macrophages. We found that ESX-1 is required for MTB to recruit diverse MNP subsets with high MTB burden. Further, MTB induces an anti-inflammatory signature that may lead to more permissive MNPs. Spatial transcriptomics revealed an upregulation of anti-inflammatory signals in MTB lesions, where monocyte-derived macrophages concentrate near MTB-infected cells. Together, our findings suggest that MTB ESX-1 mediates the recruitment and differentiation of anti-inflammatory MNPs, which MTB can infect and manipulate for survival. Single-cell suspension from harvested lungs from C57BL/6 uninfected or infected with H37Rv or H37Rv-deltaEccD for 28 days were stained and index sorted to obtain live CD11b and/or c infected cells and bystander into 384 well plates - these were processed by smartseq2.