A Role for p75 Neurotrophin Receptor in the Control of Apoptosis-Driven Hair Follicle Regression

The study from October 2000 explored the involvement of the p75 neurotrophin receptor (p75NTR) in the process of hair follicle regression during the catagen phase in mice. The researchers observed high levels of p75NTR mRNA and strong p75NTR expression in the outer root sheath of hair follicles during the transition from anagen to catagen. Experiments demonstrated that p75NTR knockout mice had a significant delay in catagen development, indicating that p75NTR is functionally important in this phase. Additionally, mice overexpressing nerve growth factor (NGF) showed an accelerated catagen phase. Neurotrophins such as NGF, brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) were found to speed up catagen in normal mouse skin but not in p75NTR-deficient skin. These results suggest that p75NTR signaling is crucial for controlling keratinocyte apoptosis during catagen and that targeting p75NTR could be a potential therapeutic approach for hair loss disorders that involve premature catagen entry. The study's conclusions are based on the analysis of over 50 longitudinally sectioned follicles from the lower back of 5 C57BL/6 mice at each time point.