Expression Patterns of Glial Cell Line-Derived Neurotrophic Factor, Neurturin, Their Cognate Receptors GFRα-1, GFRα-2, and Common Signal Transduction Element c-Ret in Human Skin Hair Follicles

In the 2008 study by Mohamed A. Adly and colleagues, the expression of glial cell line-derived neurotrophic factor (GDNF), neurturin (NTN), and their receptors GFRα-1, GFRα-2, and c-Ret were examined in human hair follicles (HFs) to understand their role in the hair cycle. Using immunofluorescence, immunoalkaline phosphatase staining, and RT-PCR, the study found that these proteins and receptors were weakly expressed during the catagen and telogen phases but strongly expressed during the anagen phase. GDNF was shown to increase keratinocyte proliferation and protect against premature catagen phase transition. The study, which included RT-PCR experiments on 50 cases and in vitro experiments with 12 HFs per group across 6 groups, concluded that GDNF and its receptors are involved in human hair follicle biology and could be potential targets for treating hair disorders related to the hair cycle.