Mast cell homeostasis depends on KIT ligand from dermal fibroblasts and perivascular cells in mouse skin

mice and single-cell RNA sequencing to identify KITLG-expressing cells in mouse ear skin. On the basis of these findings, we studied MC homeostasis using 6 mouse models with conditional Kitl deletion in epidermal and stromal populations. Our results indicate that keratinocyte-derived KITLG is dispensable for MC survival in unchallenged mouse skin. Instead, we identify dermal fibroblasts and perivascular cells as critical KITLG sources for maintaining MCs in the dermis. Overall, our study provides a detailed characterization of KITLG-expressing cells across skin regions and reveals how stromal cell types shape local KITLG availability and MC homeostasis in unchallenged mouse skin.