Investigating the Role of Notch Ligands Regulating Epidermal Stem Cell Differentiation

This study investigates the role of the Notch ligand Jag2 in epidermal stem cell differentiation. Using Jag2-cKO mice, researchers found that Jag2 is primarily expressed in basal epidermal stem cells and is crucial for early differentiation stages. Loss of Jag2 reduces Hes1 expression, leading to fewer differentiating basal cells and disorganized upper epidermal layers, although proliferation remains unaffected. Interestingly, Jag2 loss also affects neighboring melanocyte morphology, suggesting a non-autonomous role in pigment cell behavior. Despite tissue architecture anomalies, all epidermal layers remain intact under homeostatic conditions. Exposure to UV rays results in basal layer hyperplasia in Jag2-cKO epidermis, highlighting Jag2's importance in epidermal differentiation and homeostasis.