Hair Follicle Epithelial Stem Cells Contribute to Interfollicular Epidermis During Homeostasis

This study explores the role of Krox20-expressing epithelial stem cells in hair follicles and their contribution to the interfollicular epidermis (IFE) during homeostasis. Using Krox20-GFP mice and single-cell RNA sequencing, researchers identified 10 distinct clusters of Krox20+ cells, indicating their heterogeneity. Lineage tracing with Krox20-CreERT; R26-tdTomato mice showed that Krox20-lineage cells migrate from hair follicles to the IFE, contributing to both basal and suprabasal layers, which suggests active cell cycling. The study highlights the importance of Krox20-lineage cells in maintaining skin homeostasis, as their ablation led to epidermal hyperplasia and disrupted stratification. These findings underscore the significance of Krox20-expressing cells as a stem cell population essential for skin integrity and function, particularly in hairy epidermis.