Lgr5 Marks Cycling, Yet Long-Lived, Hair Follicle Stem Cells

In 2008, researchers discovered that Lgr5, a gene marker known for identifying intestinal stem cells, also marks a population of cycling, yet long-lived stem cells in mouse hair follicles. These Lgr5+ cells are multipotent and contribute to all hair follicle structures, challenging the previous belief that hair follicle stem cells are quiescent and only reside in the bulge. The study demonstrated that these cells proliferate during the anagen phase and are essential for hair follicle maintenance and regeneration. Techniques such as immunohistochemistry, flow cytometry, cell cycle analysis, and transplantation experiments on nude mice were used to confirm the stem cell properties of Lgr5+ cells. The findings suggest a reevaluation of the relationship between label-retaining cells and hair follicle stem cells, indicating that a cycling population of stem cells maintains homeostasis in hair follicles. The study's experiments were conducted in triplicate to ensure reliability.