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 three isotypes: PPARα, PPARβ (or δ), and PPARγ. All three were expressed in rodent and human skin, with PPARα contributing to epidermal barrier formation 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. It also had pro-differentiating effects on keratinocytes. Preliminary studies suggested potential roles for PPARs in hair follicle growth and melanocyte differentiation. The diverse effects of PPARs on cell proliferation and differentiation indicated that PPAR agonists or antagonists could be promising for treating skin disorders involving inflammation, cell hyperproliferation, and abnormal differentiation.