Impairment of Hair-Inducing Capacity of Three-Dimensionally Cultured Human Dermal Papilla Cells by the Ablation of STAT5

The study demonstrated that the hair-inducing capacity of three-dimensionally (3D) cultured human dermal papilla (DP) cells was significantly impaired by the knock-down of STAT5. STAT5 expression and its downstream targets, SOCS2 and SOCS3, were higher in 3D DP spheres compared to two-dimensionally (2D) cultured DP cells. Knock-down of STAT5A or STAT5B in DP spheres led to a marked reduction in hair follicle formation when implanted into nude mice, with control DP spheres inducing 79±14 hair follicles, while STAT5A and STAT5B knock-down spheres induced only 38±16 and 26±21 hair follicles, respectively. Additionally, the expression of DP signature genes ALP and Wnt10b was significantly decreased in STAT5 knock-down DP spheres. These findings suggested that STAT5 played a crucial role in maintaining the hair-inductive capacity of DP cells in 3D culture.