Lineage-Committed Fibroblast Populations Are More Efficient at Regenerating Hair Follicles in Chamber Grafting Assays Compared to Undifferentiated Embryonic Fibroblasts

The study tested the ability of undifferentiated embryonic fibroblasts (E14.5) versus more differentiated fibroblasts (E17.5 and P5) to support hair follicle formation using chamber grafting assays. Contrary to the hypothesis, E14.5 fibroblasts did not form hair follicles, while E17.5 and P5 fibroblasts did, indicating that lineage-committed fibroblasts are more efficient in hair follicle regeneration. Single-cell RNA sequencing showed that E14.5 fibroblasts were undifferentiated and homogeneous, whereas E17.5 and P5 fibroblasts were heterogeneous and had distinct molecular signatures. This suggests that differentiated fibroblasts are less susceptible to external perturbations and more capable of supporting hair follicle formation. Further research is needed to understand fibroblast differentiation mechanisms for potential regenerative therapies.