MicroRNA-205 Promotes Hair Regeneration by Modulating Mechanical Properties of Hair Follicle Stem Cells

This study investigates the role of mechanical properties, such as stiffness and actomyosin contractility, in hair follicle stem cells (SCs) and their influence on hair regeneration. The researchers found that hair follicle SCs in the bulge are inherently stiff with high actomyosin contractility, making them resistant to size changes, while hair germ (HG) progenitors are softer and undergo size fluctuations during rest periods. Upon activation, HGs show reduced contraction, which correlates with a decrease in actomyosin network strength, nuclear YAP accumulation, and cell cycle re-entry, leading to hair growth. The study identifies microRNA-205 (miR-205) as a novel regulator that can decrease actin contractility and stiffness in both the bulge and HG, thereby promoting hair regeneration in both young and old mice. This research highlights the potential of modulating cell mechanics to stimulate tissue regeneration.