β-catenin Activity in the Dermal Papilla Regulates Morphogenesis and Regeneration of Hair

The study explored the importance of β-catenin activity in the dermal papilla (DP) of hair follicles, focusing on its role in hair morphogenesis and regeneration. It was discovered that inhibiting β-catenin in the DP led to a significant decrease in cell proliferation in the hair bulb, resulting in abnormal hair types, shorter hair length, and impaired hair follicle regeneration. Mutant mice with β-catenin deletion in the DP exhibited premature catagen phase onset and a 67% reduction in proliferating cells in the hair bulb. Gene expression analysis showed dramatic changes in transcripts such as Fgf7, Fgf10, and Igfbp5, which are associated with keratinocyte proliferation and IGF signaling. The study concluded that β-catenin in the DP is essential for normal hair cycle progression and regeneration, as it regulates signaling pathways that mediate the DP's inductive effects on follicular keratinocytes. The number of mice used in the gene expression part of the study was eight per genotype, but the total number of mice used was not specified.