Background: The peroxisome proliferator-activated receptor (PPAR) activation has generally been shown to have anti-inflammatory effects and dendritic cells (DCs) are the most efficient antigen presenting cells that play an active role in the development of atherosclerosis. The effects of PPARgamma on DCs maturation and immune function remain unknown now and we, therefore, studied the influence of PPARgamma agonist ciglitazone on the maturation and immune function of DCs.
Methods: Human monocytes were purified and immature DCs derived; ciglitazone (25 micromol/L) was added to the medium for 24 hours; ox-LDL (50 microg/ml) was then added to the medium for another 24 hours. The immunophenotypic expressions (CD1a, CD40, CD86, and HLA-DR) were analyzed by FACS and endocytosis function by FITC-dextran and the cytokines secretions of culture supernatants (IL-12,IL-10,TNFalpha, and IL-2) were measured with ELISA.
Results: Ciglitazone reduced ox-LDL induced immunophenotypic expressions of DCs (CD40, CD1a, and HLA-DR). Ox-LDL inhibited the endocytosis of DCs, which was prevented by ciglitazone; ciglitazone attenuated ox-LDL induced cytokine secretions of DCs (IL-12, 116 +/- 29 versus 34 +/- 3 pg/ml*; IL-10, 49 +/- 1 versus 28 +/- 9 pg/ml*; TNFalpha, 46 +/- 16 versus 24 +/- 8 pg/ml*, *P < 0.05 compared with ox-LDL, respectively).
Conclusion: Our study suggested that one of the anti-inflammatory mechanisms of PPAR-gamma agonist ciglitazone was mediated by inhibiting the ox-LDL induced maturation and immune function of DCs.