Functions of Peroxisome Proliferator-Activated Receptors in Skin Homeostasis

The study explored the roles of peroxisome proliferator-activated receptors (PPARs) in skin homeostasis, focusing on their expression in rodent and human skin. It identified three PPAR isotypes: PPARα, PPARβ (or δ), and PPARγ, each with distinct functions. PPARα was found to contribute significantly to the formation of the epidermal barrier and sebocyte differentiation. PPARγ was involved in stimulating sebocyte development and lipogenesis but not in epidermal differentiation. PPARβ regulated late-stage sebaceous cell differentiation and was most effective in stimulating lipid production. Additionally, PPARβ had pro-differentiating effects on keratinocytes and potential roles in hair follicle growth and melanocyte differentiation. The findings suggested that PPAR agonists or antagonists could be promising for treating skin disorders involving inflammation, cell hyperproliferation, and abnormal differentiation.