Fig. 4.

Defining human dermal fibroblast heterogeneity. The study of fibroblast heterogeneity in humans, as well as the identification of distinct dermal fibroblast subpopulations, has largely relied on single-cell molecular profiling. Generally, fibroblasts are isolated from either whole dermis or skin layers that have been anatomically separated (eg, using a dermatome) (A). These fibroblasts are then subjected to single-cell sequencing (B). Based on comparison of gene expression levels (C), fibroblasts can be clustered into subgroups that share similar transcriptional profiles (D), which may represent distinct fibroblast subpopulations (E).