Spatial and single-cell transcriptional profiling identifies functionally distinct human dermal fibroblast subpopulations

Fibroblasts synthesize the extracellular matrix of connective tissue and play an essential role in maintaining tissue integrity. We have previously shown that mouse skin connective tissue, the dermis, is comprised of functionally distinct fibroblast lineages. However, the extent of fibroblast heterogeneity in human skin is unknown. Here, using a combination of spatial transcriptional profiling of human and mouse dermis and single cell transcriptional profiling of human dermal fibroblasts, we show that there are at least four distinct fibroblast populations in adult human skin. We define markers permitting prospective isolation of these cells and show that although marker expression is rapidly lost in culture, different fibroblast subpopulations retain distinct functionality in terms of Wnt signalling, T cell communication and the ability to support human epidermal reconstitution in organotypic culture. Furthermore, while some fibroblast subpopulations are spatially segregated, others are not. These findings have profound implications for normal wound healing and diseases characterized by excessive fibrosis, and suggest that ex vivo expansion or in vivo ablation of specific fibroblast subpopulations may have therapeutic applications.