Faculty Opinions Recommendation of Dermal Sheath Contraction Powers Stem Cell Niche Relocation During Hair Cycle Regression
Studysummary This study identified the dermal sheath as a driver of hair follicle regression through muscle contraction, essential for reuniting niches and stem cells to regenerate tissue structure during homeostasis.
Our plain-language summary. Not medical advice or a treatment recommendation. Consult a qualified healthcare professional before changing treatment. Full disclaimer
The study by Heitman et al. revealed that the contraction of the dermal sheath (DS) acts as a smooth muscle to facilitate the relocation of the dermal papilla (DP) during the catagen phase of the hair cycle. This biomechanical mechanism was proposed as a novel concept for niche relocation. The researchers used DS-specific targeting with the cartilage proteoglycan aggrecan (Acan) as a genetic driver to demonstrate that DS is essential for hair follicle regression. Transcriptome analysis showed that DS expresses factors related to smooth muscle contraction, and its contraction was shown to compress hair follicles, a process inhibited by a myosin phosphorylation inhibitor. In vivo 3D time-lapse analysis illustrated that DS contraction generates the force needed to push the hair shaft upward, thereby pulling the DP by its connection to the hair shaft via the epithelial strand.
