Dynamic Plasticity of Axons Within a Cutaneous Milieu

The study demonstrated that sensory axons in the skin of mice exhibited dynamic plasticity influenced by their microenvironment, particularly in response to noninvasive hair clipping. This process involved increased expression of growth protein GAP43 in axons, activation of epidermal and perifollicular cells, and elevated mRNA levels of Sox2 and glial fibrillary acidic protein. Hepatic growth factor (HGF) and its receptor c-Met were identified as key players, with increased HGF mRNA and protein expression in epidermal cells, perifollicular cells, and sensory axons. The study highlighted the critical interactions between sensory axons and their cutaneous environment, suggesting that follicular-originating signals, particularly involving HGF and Rac1, facilitated axonal remodeling. These findings suggested that simple hair clipping could trigger axon remodeling and growth responses in the skin.