Generation of the Krt24-CreERT2 Mouse Line Targeting Outer Bulge Hair Follicle Cells

The study successfully generated a Krt24-CreERT2 mouse line to target outer bulge hair follicle stem cells (OB HFSCs), which are crucial for hair follicle development and damage repair. By crossing these mice with Rosa26LSL-tdTomato or Rosa26LSL-DTR lines, researchers could specifically label or ablate Krt24+ cells. The study demonstrated that Krt24+ cells differentiate into the outer root sheath during the anagen phase and persist into the telogen phase. Ablation of these cells delayed anagen initiation and reduced survival rates following ionizing radiation, highlighting their essential role in hair follicle regeneration and stress response. This mouse model provides a valuable tool for studying the functional roles of Krt24+ OB HFSCs in hair follicle cycling and cutaneous homeostasis. The study involved small groups of mice, typically n = 3 per group, with some experiments involving n = 18 mice.