ADAM10 shapes myeloid antigen-presenting cell homeostasis in the splenic marginal zone

The spleen contains phenotypically and functionally distinct cDC1 and cDC2 subpopulations, which each can be divided into several smaller and less-well characterized subsets. Despite advances in understanding the complexity of DC ontogeny and function by transcriptional programming, the significance of post-translational modifications in controlling tissue-specific cDC (subset) immunobiology remains elusive. Here, we identified the cell surface-expressed A-disintegrin-and-metalloproteinase 10 (ADAM10) as an essential regulator of cDC1 and cDC2 homeostasis in the splenic marginal zone (MZ). Mice with a CD11c-specific deletion of ADAM10 (ADAM10?CD11c) exhibited a complete loss of splenic ESAMhi cDC2A, because ADAM10 controlled their commitment, differentiation, survival, and EBI2-mediated localization within the MZ. Moreover, we discovered that ADAM10 is a molecular switch regulating cDC2 subset heterogeneity in the spleen, as this unbalanced cDC2A homeostasis in the absence of ADAM10 was compensated for by the emergence of a novel Clec12a+ cDC2B subset, closely resembling cDC2 generally found in peripheral lymph nodes. Moreover, in ADAM10?CD11c mice terminal differentiation of cDC1 was abrogated, resulting in reduced numbers of Langerin+ cDC1. Overall design: Transcriptome analysis of WT and ADAM10-deficient splenic CD4+, CD8+ and CD4-CD8- conventional dendritic cells subsets