[Role of the peroxisome proliferator-activated receptors (PPARS) in the regulation of lipids and inflammation control]

Abstract

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the nuclear receptor family. The hypolipidemic fibrates and the antidiabetic glitazones are synthetic ligands for PPAR alpha and PPAR gamma, respectively. Furthermore, fatty acids and eicosanoids are natural PPAR ligands. PPARs function as regulators of lipid and lipoprotein metabolism and glucose homeostasis and influence cellular proliferation, differentiation and apoptosis. PPAR alpha is highly expressed in tissues such as liver, muscle, kidney and heart, where it stimulates the beta-oxidative degradation of fatty acids. PPAR alpha furthermore mediates the action of the hypolipidemic drugs of the fibrate class on plasma lipoprotein metabolism. PPAR gamma is predominantly expressed in intestine and adipose tissue. PPAR gamma triggers adipocyte differentiation and promotes lipid storage. In addition, PPARs play a role in inflammation control. PPAR activators inhibit the activation of inflammatory response genes by negatively interfering with the NF-kappa B and AP-1 signalling pathways. PPAR activators exert these anti-inflammatory activities in different immunological and vascular wall cell types such as monocyte-macrophages, endothelial, epithelial and smooth muscle cells in which PPARs are expressed. These findings indicate a modulatory role for PPARs in the control of the inflammatory response with potential therapeutic applications in inflammation-related diseases, such as atherosclerosis.