Developmental origins of fibroblasts determine their scarring potential in wound healing
Fibroblasts are the primary cells responsible for depositing extracellular matrix proteins during wound repair and fibrosis. Progress towards the development of treatments aimed at reducing scars has been hampered by our limited understanding of specific fibroblast populations responsible for fibrotic versus regenerative healing. Using a four-site wounding model in mice, we observed that neural crest-derived facial wounds heal with less scarring than cephalic mesoderm-derived scalp wounds, lateral plate mesoderm-derived ventral wounds, and paraxial mesoderm-derived dorsal wounds. Single-cell RNA sequencing identified increased expression of Robo2 and downstream Eid1 in neural-crest derived facial fibroblasts compared to fibroblasts from other sites. Subsequent fibroblast transplantation experiments showed that Robo2 and Eid1 are required for facial fibroblasts' intrinsic reduced fibrotic potential. This is maintained by the EID1-mediated inhibition of EP300 histone acetyltransferase, leading to a more transcriptionally silent chromatin landscape, including around extracellular matrix genes. Mimicking EID1's endogenous activity, both small-molecule and transgenic repression of EP300 in dorsal wounds promoted facial-like healing with reduced scarring. Overall, these data highlight the importance of the ROBO2-EID1-EP300 signaling axis in facial wound healing, and demonstrate our ability to modulate the embryologically determined fibrogenic potential of fibroblasts as a therapeutic approach to minimize scar formation. Overall design: We examined the behaviour of fibroblasts from different regions of the mouse skin including facial, scalp, ventrum and dorsum.