STAT5 Activation in the Dermal Papilla Is Important for Hair Follicle Growth Phase Induction

The study from 2016 explored the significance of STAT5 activation in the dermal papilla (DP) for the induction of the hair growth phase, known as anagen. It was discovered that STAT5 activation is crucial for the transition from the resting phase (telogen) to the growth phase (anagen) in hair follicles. Conditional knockout of STAT5 in the DP led to a delay in anagen entry, suggesting that STAT5 acts as a mesenchymal switch for initiating hair growth. Gene expression analysis indicated that STAT5 influences hair cycling by regulating the expression of genes involved in signaling pathways like Wnt, Notch, and FGF. The study also found that STAT5 activation in the DP does not rely on JAK1/2 signaling, as evidenced by the lack of effect from the JAK1/2 inhibitor ruxolitinib on STAT5 phosphorylation. The research, conducted on mice, implies that targeting STAT5 could be a potential strategy for hair follicle-related treatments, although further investigation is needed to fully understand its role within the DP.