Localization of Cathepsins B, D, L, LAMP-1 and .MU.-Calpain in Developing Hair Follicles.

This study investigated the roles of autophagy and proteolysis in the development of hair follicles in neonate rats, focusing on the differentiation of tissues within the internal root sheath and hair shaft. The research utilized electron microscopy and immunohistochemistry to observe these processes. Autophagy was notably present during the keratinization of the hair shaft, particularly in the hair cuticle area. The study found significant co-localization of cathepsins B, D, L, LAMP-1, and μ-calpain in various parts of the hair follicle, including the external root sheath and keratinizing layers. This suggested that lysosomal proteases and cytoplasmic enzymes worked together to facilitate the cytoplasmic conversion and terminal differentiation of hair follicle cells.