PPARs belong to the nuclear hormone receptor superfamily, one of the largest families of transcription factors 31. PPARs heterodimerize with Retinoid X Receptor (RXR), another nuclear hormone receptor, and act as ligand-regulated transcription factors 23. There are three known isotypes of PPARs: PPARα, PPARβ also named PPARδ (PPARβ/δ), and PPARγ that each have distinct expression patterns, tissue distribution and physiological functions 18, 35. Endogenous ligands of PPARs include endocannabinoids, fatty acids and fatty acid derivatives (e.g. polyunsaturated fatty acids, eicosanoids and oxidized phospholipids) 26, 61.
