Mesenchyme Governs Hair Follicle Induction

The study investigates the role of mesenchyme in hair follicle development, revealing that the mesenchyme from the back skin of mouse embryos can induce hair follicle formation even before the formation of the dermal condensate, which is a precursor to the dermal papilla. The research demonstrates that unpatterned mesenchyme can initiate hair follicle development in oral epithelium, suggesting its inductive potential is not limited to pre-patterned skin regions. The study also examines the effects of Wnt signalling and Bmp activity inhibition on hair follicle induction. It finds that while the Wnt agonist R-spondin-1 triggers early placode-specific transcriptional responses, neither R-spondin-1 alone nor in combination with a Bmp receptor inhibitor is sufficient to induce hair follicle formation. This indicates that other factors are involved in the induction process, and the exact hair follicle-inducing signal remains unidentified.