PPAR-delta

The most broadly expressed member of the subfamily, PPAR-delta (PPAR delta, gene PPARD) tunes cellular energy metabolism in nearly every tissue, with particularly strong actions in skeletal muscle, skin and colon. Upon activation by unsaturated fatty acids or synthetic agonists such as GW501516, it heterodimerizes with RXR and induces genes for fatty acid oxidation, mitochondrial uncoupling and HDL metabolism. PPAR delta drives the switch toward oxidative type I muscle fibers and enhances endurance capacity in mouse models, and it accelerates keratinocyte migration in wound healing. Its role is double-edged: PPAR delta signaling can promote colorectal tumor progression under inflammatory conditions, and agonists were halted in clinical development, leaving recombinant PPARD protein mainly a research and screening tool.