DGAT1 Modulates Hair Cycling and Is Essential for Retinoid Homeostasis in the Skin

The study demonstrated that the enzyme encoded by Dgat1 is crucial for retinoid homeostasis in the skin by functioning as a retinol acyltransferase (ARAT), which esterifies retinol to prevent excessive retinoic acid (RA) accumulation. In murine skin, Dgat1 accounted for 90% of ARAT activity. The absence of Dgat1 led to elevated retinol and RA levels, causing cyclical alopecia due to excessive hair shedding. This condition was preventable by dietary retinol deprivation. Additionally, Dgat1-/- skin showed increased susceptibility to retinol toxicity. The findings indicated that Dgat1's retinoid-related functions are epidermis-autonomous, highlighting its protective role against retinoid toxicity in the skin.