Developmental signals in skin morphogenesis

The document from 2004 examined the mechanisms of skin and hair follicle development, emphasizing the role of keratinocytes and signaling interactions in epidermal and hair follicle differentiation. Key signaling molecules like Wnt, p63, myc, and hedgehog were identified as crucial for epidermal development. The study highlighted the role of β-catenin signaling in hair follicle and sebaceous gland function, showing that transient activation in adult mouse epidermis could induce new hair follicles, while continuous activation maintained hair follicle tumors. It demonstrated that adult epidermis could undergo β-catenin-induced lineage conversion, affecting sebocyte differentiation and enabling reprogramming of epidermis and sebaceous glands. Long-term β-catenin activation led to benign tumors resembling trichofolliculomas, which regressed when activation ceased. The research also noted the overexpression of PTCH and IHH in sebaceous neoplasia, with ΔNLef1 upregulating IHH and stimulating sebocyte proliferation, providing insights into skin-related disorders and potential therapeutic targets.