title: Rosiglitazone and retinoic acid induce uncoupling protein-1 (UCP-1) in a p38 mitogen-activated protein kinase-dependent manner in fetal primary brown adipocytes.
abstract: Brown adipose tissue expresses the thermogenic uncoupling protein-1 (UCP-1), which is positively regulated by peroxisome proliferator-activated receptor (PPAR) agonists and retinoids through the activation of the heterodimers PPAR/retinoid X receptor (RXR) and retinoic acid receptor (RAR)/RXR and binding to specific elements in the ucp-1 enhancer. In this study we show that in fetal rat brown adipocyte primary cultures the PPARgamma agonist rosiglitazone (Rosi), as well as retinoic acids 9-cis-retinoic acid and all-trans-retinoic acid also have "extragenic" effects and induce p44/p42 and p38 mitogen-activated protein kinase (p38MAPK) activation. The latter is involved in UCP-1 gene expression, because inhibition of p38MAPK activity with PD169316 impairs the ability of Rosi and retinoids for UCP-1 induction. The inhibitory effects of PD169316 are mimicked by the antioxidant GSH, suggesting a role for reactive oxygenated species (ROS) generation in the increase of UCP-1 expression in response either to Rosi or 9-cis-retinoic acid. Thus, we propose that Rosi and retinoids act as PPAR/RXR and RAR/RXR agonists and also activate p38MAPK. These two coordinated actions could result in a high increase of transcriptional activity on the ucp-1 enhancer and hence on thermogenesis. PPARalpha and gamma agonists but not retinoids also increase UCP-3 expression in fetal brown adipocytes. However, the regulation of UCP-3, which is not involved in thermogenesis, seems to differ from UCP-1 given the fact that is not affected by p38MAPK inhibition.
authors.affiliation: Departamento de Bioquimica y Biologia Molecular II, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: Teresa
authors.initials: T
authors.lastname: Teruel
authors.forename: Rosario
authors.initials: R
authors.lastname: Hernandez
authors.forename: Manuel
authors.initials: M
authors.lastname: Benito
authors.forename: Margarita
authors.initials: M
authors.lastname: Lorenzo
mesh_terms: D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism; D002001:Adipose Tissue, Brown / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005333:Fetus; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D005978:Glutathione / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D007473:Ion Channels; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D024101:Mitochondrial Proteins; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000077154:Rosiglitazone; D013844:Thiazoles / Q000494:pharmacology*; D045162:Thiazolidinediones; D014212:Tretinoin / Q000737:chemistry / Q000494:pharmacology*; D014475:Uncoupling Agents / Q000378:metabolism*; D000071256:Uncoupling Protein 1; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D002352:Carrier Proteins; D016895:Culture Media, Serum-Free; D004791:Enzyme Inhibitors; D007093:Imidazoles; D007473:Ion Channels; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D011993:Recombinant Fusion Proteins; D013844:Thiazoles; D045162:Thiazolidinediones; C000604373:Ucp1 protein, rat; D014475:Uncoupling Agents; D000071256:Uncoupling Protein 1; D000077154:Rosiglitazone; D014212:Tretinoin; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D005978:Glutathione; C408604:2-(4-nitrophenyl)-4-(4-fluorophenyl)-5-(4-pyridinyl)-1H-imidazole