gw-7845 and Inflammation

Topics: Animals; Diabetes Mellitus; Drug Design; Humans; Hyperlipidemias; Hypertension; Inflammation; Ligands; Models, Molecular; Neoplasms; Nuclear Proteins; Obesity; Receptors, Cytoplasmic and Nuclear; Transcription Factors

We previously demonstrated that, in the MC615 cartilage cell line, the p38/NF-kB pathway is activated both during differentiation and in response to an inflammatory stimulus. In both cases, the p38/NF-kB pathway activation leads to the expression of the lipocalin SIP24 and of COX-2. Given the fact that, in the same cells, the COX-2 expression is sustained during the inflammation resolution, at the same time that the SIP24 expression is suppressed, in the present study we tested the hypothesis that COX-2 products play a role in SIP24 repression. Taken together, our results suggest that, during the resolution of inflammation, COX-2 represses the acute phase protein SIP24 and restores physiological conditions, possibly through a pathway involving PPARgamma. Experimental evidences being the following: (1) 15-deoxy-delta 12,14-prostaglandin J(2), but not PGE(2): (i) inhibits the expression of SIP24 in the inflammatory phase and induces COX-2 synthesis; (ii) represses NF-kB activation induced by LPS; (iii) represses the synthesis of microsomal PGE Synthase-1 induced by LPS. (2) PPARgamma and PPARalpha are present in MC615 cells in both proliferating and hyperconfluent cultures. (3) PPARgamma ligand GW7845, but not PPARalpha ligand GW7647: (i) represses the expression of SIP24 induced by LPS; (ii) induces COX-2 expression. (4) p38 is involved in the PPARgamma mediated induction of COX-2. In fact 15-deoxy-delta 12,14-prostaglandin J(2) activates p38 and the cell pretreatment with the p38 specific inhibitor SB203580 represses the expression of COX-2 induced by both the 15-deoxy-delta12,14-prostaglandin J(2) and the PPARgamma ligand GW7845.

Topics: Acute-Phase Proteins; Animals; Anti-Inflammatory Agents, Non-Steroidal; Butyrates; Cartilage; Cells, Cultured; Chondrocytes; Cyclooxygenase 2; Diclofenac; Dinoprostone; Down-Regulation; Enzyme Induction; Enzyme Repression; Imidazoles; Inflammation; Intramolecular Oxidoreductases; Lipocalin-2; Lipocalins; Lipopolysaccharides; Mice; NF-kappa B; Oncogene Proteins; Oxazoles; p38 Mitogen-Activated Protein Kinases; Phenylurea Compounds; PPAR alpha; PPAR gamma; Prostaglandin D2; Prostaglandin-E Synthases; Protein Kinase Inhibitors; Pyridines; Signal Transduction; Time Factors; Tyrosine