Expression of Peroxisome Proliferator Activated Receptors (PPARs) in Human Hair Follicles and PPARa Involvement in Hair Growth
Nelly Billoni, Bruno Buan, Brigitte Gautier, Christine Collin, Olivier Gaillard, Yann F. Mahé, Bruno A. Bernard
Peroxisome proliferator-activated receptors (PPARs), which belong to the nuclear hormone receptor superfamily, have recently been described as potent key regulators of epidermal development. As 1,25-dihydroxyvitamin D3, retinoic acid and triiodothyronine are known to exert effects on skin and hair follicle growth through similar receptors, we decided to investigate both the expression pattern of the PPARα, -δ and -γ subtypes and their role in human hair follicles. Using reverse transcriptase-polymerase chain reaction and immunohistochemistry, we established that PPAR α, -δ and -γ were expressed in both dermal and epithelial human hair follicle cells. Additionally, we evaluated the dose effect of clofibrate, a PPARα ligand, on the survival of human hair follicles in culture. A beneficial effect was observed within a narrow range of concentrations.