Murine Epidermal Ceramide Synthase 4 Is a Key Regulator of Skin Barrier Homeostasis

The study demonstrated that Ceramide Synthase 4 (CerS4) was essential for maintaining skin barrier homeostasis in mice. Loss of CerS4 led to disrupted lipid metabolism, resulting in skin abnormalities such as acanthosis, hyperkeratosis, and immune cell accumulation, indicative of chronic skin barrier disease. The absence of CerS4 altered ceramide composition and cholesterol metabolism, impairing barrier function and triggering a repair response. The findings emphasized CerS4's crucial role in lipid homeostasis and its potential implications for understanding human skin barrier diseases, including atopic dermatitis. The research provided insights into the molecular differences between barrier maintenance and establishment, highlighting the importance of lipid metabolism in skin health.