Peroxisome proliferator-activated receptor γ activators inhibit interleukin-12 production in murine dendritic cells

Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear receptor superfamily. They are divided into three subtypes (alpha, beta or delta, and gamma) and are involved in lipid and glucose homeostasis and in the control of inflammation. In this study, we analyzed the expression of PPARs in murine dendritic cells (DCs), the most potent antigen presenting cells. We find that immature as well as mature spleen-derived DCs express PPAR gamma, but not PPAR alpha, mRNA and protein. We also show that the PPAR gamma activator rosiglitazone does not interfere with the maturation of DCs in vitro nor modifies their ability to activate naive T lymphocytes in vivo. Finally, we present evidence that PPAR gamma activators down-modulate the CD40-induced secretion of interleukin-12, a potent Th1-driving factor. These data suggest a possible role for PPAR gamma in the regulation of immune responses. (C) 2000 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.