Dermal Wnt/β-Catenin Signaling Controls Hair Follicle Dermal Condensate Size During Development

The study by Chen, Sun, Gupta, and Myung from Yale University investigated the role of dermal Wnt/β-catenin signaling in hair follicle development. They found that ablating β-catenin expression in dermal cells just prior to hair follicle initiation did not affect the number or pattern of hair follicles but resulted in smaller hair germs due to decreased numbers of epithelial placode cells and associated dermal condensate cells. Lineage tracing analysis indicated that β-catenin deficient dermal cells contributed to dermal condensates similarly to non-recombined cells, suggesting a potential non-cell autonomous role for dermal Wnt/β-catenin in controlling dermal condensate formation. The loss of dermal β-catenin at earlier time points completely prevented the formation of hair follicle placodes and dermal condensates. These findings suggest a critical temporal window for dermal Wnt/β-catenin activation in hair follicle initiation and indicate that dermal β-catenin may regulate dermal condensate size non-cell autonomously, providing insights into tissue patterning and hair follicle regeneration.