GW0742, A HIGH AFFINITY PPAR-β/δ AGONIST REDUCES LUNG INFLAMMATION INDUCED BY BLEOMYCIN INSTILLATION IN MICE

Peroxisome Proliferator-Activated Receptor (beta/delta belongs to a family of ligand-activated transcription factors. Recent data have clarified its metabolic roles and enhanced the potential role of this receptor as a pharmacological target. Moreover, although its role in acute inflammation remains unclear, being the nuclear receptor PPAR beta/delta widely expressed in many tissues, including the vascular endothelium, we assume that the infiltration of PMNs into tissues, a prominent feature in inflammation, may also be related to PPAR beta/delta. Mice subjected to intratracheal instillation of bleomycin (BLEO, 1 mg/kg), a glycopeptide produced by the bacterium Streptomyces verticillus, develop lung inflammation and injury characterized by a significant neutrophil infiltration and tissue oedema. Therefore, the aim of this study is to investigate the effects of GW0742, a synthetic high affinity PPAR beta/delta agonist, and its possible role in preventing the advance of inflammatory and apoptotic processes induced by bleomycin, that long-term leads to the appearance of pulmonary fibrosis. Our data showed that GW0742-treatment (0.3 mg/Kg, 10% DMSO, i.p.) has therapeutic effects on pulmonary damage, decreasing many inflammatory and apoptotic parameters detected by measurement of: 1) cytokine production; 2) leukocyte accumulation, indirectly measured as decrease of myeloperoxidase (MPO) activity; 3) I kappa B alpha degradation and NF-kappa B nuclear translocation; 4) ERK phosphorylation; 5) stress oxidative by NO formation due to iNOS expression; 6) nitrotyrosine and PAR localization; 7) the degree of apoptosis, evaluated by Bax and Bcl-2 balance, FAS ligand expression and TUNEL staining. Taken together, our results clearly show that GW0742 reduces the lung injury and inflammation due to the intratracheal BLEO-instillation in mice.