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Skoczyńska A, Ołdakowska M, Dobosz A, Adamiec R, Gritskevich S, Jonkisz A, Lebioda A, Adamiec-Mroczek J, Małodobra-Mazur M, Dobosz T. PPARs in Clinical Experimental Medicine after 35 Years of Worldwide Scientific Investigations and Medical Experiments. Biomolecules 2024; 14:786. [PMID: 39062500 PMCID: PMC11275227 DOI: 10.3390/biom14070786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 07/28/2024] Open
Abstract
This year marks the 35th anniversary of Professor Walter Wahli's discovery of the PPARs (Peroxisome Proliferator-Activated Receptors) family of nuclear hormone receptors. To mark the occasion, the editors of the scientific periodical Biomolecules decided to publish a special issue in his honor. This paper summarizes what is known about PPARs and shows how trends have changed and how research on PPARs has evolved. The article also highlights the importance of PPARs and what role they play in various diseases and ailments. The paper is in a mixed form; essentially it is a review article, but it has been enriched with the results of our experiments. The selection of works was subjective, as there are more than 200,000 publications in the PubMed database alone. First, all papers done on an animal model were discarded at the outset. What remained was still far too large to describe directly. Therefore, only papers that were outstanding, groundbreaking, or simply interesting were described and briefly commented on.
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Affiliation(s)
- Anna Skoczyńska
- Department of Internal and Occupational Medicine and Hypertension, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw, Poland;
| | - Monika Ołdakowska
- Department of Forensic Medicine, Division of Molecular Techniques, Wroclaw Medical University, M. Sklodowskiej-Curie 52, 50-369 Wroclaw, Poland; (M.O.); (A.J.); (A.L.); (M.M.-M.); (T.D.)
| | - Agnieszka Dobosz
- Department of Basic Medical Sciences and Immunology, Division of Basic Medical Sciences, Wroclaw Medical University, Borowska 211, 50-556 Wrocław, Poland
| | - Rajmund Adamiec
- Department of Diabetology and Internal Medicine, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw, Poland;
- Department of Internal Medicine, Faculty of Medical and Technical Sciences, Karkonosze University of Applied Sciences, Lwówiecka 18, 58-506 Jelenia Góra, Poland
| | - Sofya Gritskevich
- Department of Forensic Medicine, Division of Molecular Techniques, Wroclaw Medical University, M. Sklodowskiej-Curie 52, 50-369 Wroclaw, Poland; (M.O.); (A.J.); (A.L.); (M.M.-M.); (T.D.)
| | - Anna Jonkisz
- Department of Forensic Medicine, Division of Molecular Techniques, Wroclaw Medical University, M. Sklodowskiej-Curie 52, 50-369 Wroclaw, Poland; (M.O.); (A.J.); (A.L.); (M.M.-M.); (T.D.)
| | - Arleta Lebioda
- Department of Forensic Medicine, Division of Molecular Techniques, Wroclaw Medical University, M. Sklodowskiej-Curie 52, 50-369 Wroclaw, Poland; (M.O.); (A.J.); (A.L.); (M.M.-M.); (T.D.)
| | - Joanna Adamiec-Mroczek
- Department of Ophthalmology, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw, Poland;
| | - Małgorzata Małodobra-Mazur
- Department of Forensic Medicine, Division of Molecular Techniques, Wroclaw Medical University, M. Sklodowskiej-Curie 52, 50-369 Wroclaw, Poland; (M.O.); (A.J.); (A.L.); (M.M.-M.); (T.D.)
| | - Tadeusz Dobosz
- Department of Forensic Medicine, Division of Molecular Techniques, Wroclaw Medical University, M. Sklodowskiej-Curie 52, 50-369 Wroclaw, Poland; (M.O.); (A.J.); (A.L.); (M.M.-M.); (T.D.)
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Fuior EV, Zvintzou E, Filippatos T, Giannatou K, Mparnia V, Simionescu M, Gafencu AV, Kypreos KE. Peroxisome Proliferator-Activated Receptor α in Lipoprotein Metabolism and Atherosclerotic Cardiovascular Disease. Biomedicines 2023; 11:2696. [PMID: 37893070 PMCID: PMC10604751 DOI: 10.3390/biomedicines11102696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/26/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are a group of ligand-binding transcription factors with pivotal action in regulating pleiotropic signaling pathways of energetic metabolism, immune responses and cell proliferation and differentiation. A significant body of evidence indicates that the PPARα receptor is an important modulator of plasma lipid and lipoprotein metabolism, with pluripotent effects influencing the lipid and apolipoprotein cargo of both atherogenic and antiatherogenic lipoproteins and their functionality. Clinical evidence supports an important role of PPARα agonists (fibric acid derivatives) in the treatment of hypertriglyceridemia and/or low high-density lipoprotein (HDL) cholesterol levels, although the effects of clinical trials are contradictory and point to a reduction in the risk of nonfatal and fatal myocardial infarction events. In this manuscript, we provide an up-to-date critical review of the existing relevant literature.
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Affiliation(s)
- Elena Valeria Fuior
- Institute of Cellular Biology and Pathology, “Nicolae Simionescu” of the Romanian Academy, 050568 Bucharest, Romania; (E.V.F.); (E.Z.); (M.S.)
| | - Evangelia Zvintzou
- Institute of Cellular Biology and Pathology, “Nicolae Simionescu” of the Romanian Academy, 050568 Bucharest, Romania; (E.V.F.); (E.Z.); (M.S.)
- Pharmacology Laboratory, Department of Medicine, University of Patras, 26500 Rio Achaias, Greece; (K.G.); (V.M.)
| | - Theodosios Filippatos
- Internal Medicine Clinic, Department of Medicine, University of Crete, 71500 Heraklion, Greece;
| | - Katerina Giannatou
- Pharmacology Laboratory, Department of Medicine, University of Patras, 26500 Rio Achaias, Greece; (K.G.); (V.M.)
| | - Victoria Mparnia
- Pharmacology Laboratory, Department of Medicine, University of Patras, 26500 Rio Achaias, Greece; (K.G.); (V.M.)
| | - Maya Simionescu
- Institute of Cellular Biology and Pathology, “Nicolae Simionescu” of the Romanian Academy, 050568 Bucharest, Romania; (E.V.F.); (E.Z.); (M.S.)
| | - Anca Violeta Gafencu
- Institute of Cellular Biology and Pathology, “Nicolae Simionescu” of the Romanian Academy, 050568 Bucharest, Romania; (E.V.F.); (E.Z.); (M.S.)
| | - Kyriakos E. Kypreos
- Institute of Cellular Biology and Pathology, “Nicolae Simionescu” of the Romanian Academy, 050568 Bucharest, Romania; (E.V.F.); (E.Z.); (M.S.)
- Pharmacology Laboratory, Department of Medicine, University of Patras, 26500 Rio Achaias, Greece; (K.G.); (V.M.)
- Department of Life Sciences, School of Sciences, European University Cyprus, 2404 Nicosia, Cyprus
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3
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Xue Y, Guo C, Hu F, Zhu W, Mao S. PPARA/RXRA signalling regulates the fate of hepatic non-esterified fatty acids in a sheep model of maternal undernutrition. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158548. [PMID: 31676441 DOI: 10.1016/j.bbalip.2019.158548] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 09/21/2019] [Accepted: 09/25/2019] [Indexed: 01/06/2023]
Abstract
Maternal undernutrition during late gestation accelerates body fat mobilization to provide more energy for foetal growth and development, which unbalances metabolic homeostasis and results in serious lipid metabolism disorder. However, detailed regulatory mechanisms are poorly understood. Here, a sheep model was used to explore the regulatory role of PPARA/RXRA signalling in hepatic lipid metabolism in undernutrition based on RNA sequencing and cell experiments. KOG function classification showed that lipid transport and metabolism was markedly altered in an undernourished model. In detail, when compared with the controls, fatty acid transport and oxidation and triglyceride metabolism were up-regulated in an undernourished model, while fatty acid synthesis, steroid synthesis, and phospholipid metabolism were down-regulated. Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis demonstrated that PPARA/RXRA signalling pathway was altered. Moreover, PPARA signalling associated genes were positively correlated with hepatic non-esterified fatty acid (NEFA) levels, while retinol metabolism associated genes were negatively correlated with blood beta-hydroxybutyric acid (BHBA) levels. Results of primary hepatocytes showed that NEFAs could activate PPARA signalling and facilitate fatty acid oxidation (FAO) and ketogenesis, while BHBA could inhibit RXRA signalling and repress FAO and ketogenesis. Excessively accumulated NEFAs in hepatocytes promoted triglyceride synthesis. Furthermore, activation of PPARA/RXRA signalling by WY14643 and 9-cis-retinoic acid could enhance FAO and ketogenesis and reduce NEFAs accumulation and esterification. Our findings elucidate the regulatory mechanisms of NEFAs and BHBA on lipid metabolism as well as the potential role of the PPARA/RXRA signalling pathway in hepatic lipid metabolism, which may contribute to exploring new strategies to maintain lipid metabolic homeostasis in human beings.
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Affiliation(s)
- Yanfeng Xue
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; National Center for International Research on Animal Gut Nutrition, National Experimental Teaching Demonstration Center of Animal Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Changzheng Guo
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; National Center for International Research on Animal Gut Nutrition, National Experimental Teaching Demonstration Center of Animal Science, Nanjing Agricultural University, Nanjing 210095, China.
| | - Fan Hu
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; National Center for International Research on Animal Gut Nutrition, National Experimental Teaching Demonstration Center of Animal Science, Nanjing Agricultural University, Nanjing 210095, China.
| | - Weiyun Zhu
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; National Center for International Research on Animal Gut Nutrition, National Experimental Teaching Demonstration Center of Animal Science, Nanjing Agricultural University, Nanjing 210095, China.
| | - Shengyong Mao
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; National Center for International Research on Animal Gut Nutrition, National Experimental Teaching Demonstration Center of Animal Science, Nanjing Agricultural University, Nanjing 210095, China.
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Ruppert PMM, Park JG, Xu X, Hur KY, Lee AH, Kersten S. Transcriptional profiling of PPARα-/- and CREB3L3-/- livers reveals disparate regulation of hepatoproliferative and metabolic functions of PPARα. BMC Genomics 2019; 20:199. [PMID: 30866796 PMCID: PMC6416987 DOI: 10.1186/s12864-019-5563-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Accepted: 02/25/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Peroxisome Proliferator-Activated receptor α (PPARα) and cAMP-Responsive Element Binding Protein 3-Like 3 (CREB3L3) are transcription factors involved in the regulation of lipid metabolism in the liver. The aim of the present study was to characterize the interrelationship between PPARα and CREB3L3 in regulating hepatic gene expression. Male wild-type, PPARα-/-, CREB3L3-/- and combined PPARα/CREB3L3-/- mice were subjected to a 16-h fast or 4 days of ketogenic diet. Whole genome expression analysis was performed on liver samples. RESULTS Under conditions of overnight fasting, the effects of PPARα ablation and CREB3L3 ablation on plasma triglyceride, plasma β-hydroxybutyrate, and hepatic gene expression were largely disparate, and showed only limited interdependence. Gene and pathway analysis underscored the importance of CREB3L3 in regulating (apo)lipoprotein metabolism, and of PPARα as master regulator of intracellular lipid metabolism. A small number of genes, including Fgf21 and Mfsd2a, were under dual control of PPARα and CREB3L3. By contrast, a strong interaction between PPARα and CREB3L3 ablation was observed during ketogenic diet feeding. Specifically, the pronounced effects of CREB3L3 ablation on liver damage and hepatic gene expression during ketogenic diet were almost completely abolished by the simultaneous ablation of PPARα. Loss of CREB3L3 influenced PPARα signalling in two major ways. Firstly, it reduced expression of PPARα and its target genes involved in fatty acid oxidation and ketogenesis. In stark contrast, the hepatoproliferative function of PPARα was markedly activated by loss of CREB3L3. CONCLUSIONS These data indicate that CREB3L3 ablation uncouples the hepatoproliferative and lipid metabolic effects of PPARα. Overall, except for the shared regulation of a very limited number of genes, the roles of PPARα and CREB3L3 in hepatic lipid metabolism are clearly distinct and are highly dependent on dietary status.
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Affiliation(s)
- Philip M. M. Ruppert
- Nutrition, Metabolism and Genomics group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708WE, Wageningen, the Netherlands
| | - Jong-Gil Park
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, 1300 York Ave, New York, NY 10065 USA
- Present address: Biotherapeutics Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141 South Korea
| | - Xu Xu
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, 1300 York Ave, New York, NY 10065 USA
- Present address: Division of Gastroenterology and Hepatology, Joan & Sanford I. Weill Department of Medicine, Weill Cornell Medicine, New York, NY 10021 USA
| | - Kyu Yeon Hur
- Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicin, Seoul, South Korea
| | - Ann-Hwee Lee
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, 1300 York Ave, New York, NY 10065 USA
- Present address: Regeneron Pharmaceuticals, 777 Old Saw Mill River Rd, Tarrytown, NY 10591 USA
| | - Sander Kersten
- Nutrition, Metabolism and Genomics group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708WE, Wageningen, the Netherlands
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Frkic RL, Chua BS, Shin Y, Pascal BD, Novick SJ, Kamenecka TM, Griffin PR, Bruning JB. Structural and Dynamic Elucidation of a Non-acid PPAR γ Partial Agonist: SR1988. NUCLEAR RECEPTOR RESEARCH 2018; 5. [PMID: 30906767 PMCID: PMC6428214 DOI: 10.11131/2018/101350] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Targeting peroxisome proliferator-activated receptor γ (PPARγ) by synthetic compounds has been shown to elicit insulin sensitising properties in type 2 diabetics. Treatment with a class of these compounds, the thiazolidinediones (TZDs), has shown adverse side effects such as weight gain, fluid retention, and congestive heart failure. This is due to their full agonist properties on the receptor, where a number of genes are upregulated beyond normal physiological levels. Lessened transactivation of PPARγ by partial agonists has proved beneficial in terms of reducing side effects, while still maintaining insulin sensitising properties. However, some partial agonists have been associated with unfavourable pharmacokinetic profiles due to their acidic moieties, often causing partitioning to the liver. Here we present SR1988, a new partial agonist with favourable non-acid chemical properties. We used a combination of X-ray crystallography and hydrogen/deuterium exchange (HDX) to elucidate the structural basis for reduced activation of PPARγ by SR1988. This structural analysis reveals a mechanism that decreases stabilisation of the AF2 coactivator binding surface by the ligand.
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Affiliation(s)
- Rebecca L Frkic
- Institute for Photonics and Advanced Sensing (IPAS), School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Benjamin S Chua
- Institute for Photonics and Advanced Sensing (IPAS), School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Youseung Shin
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Bruce D Pascal
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida 33458, United States.,Omics Informatics LLC, 1050 Bishop Street #517, Honolulu, HI, 96813, Hawaii
| | - Scott J Novick
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Theodore M Kamenecka
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Patrick R Griffin
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - John B Bruning
- Institute for Photonics and Advanced Sensing (IPAS), School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia
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Frkic RL, Marshall AC, Blayo AL, Pukala TL, Kamenecka TM, Griffin PR, Bruning JB. PPARγ in Complex with an Antagonist and Inverse Agonist: a Tumble and Trap Mechanism of the Activation Helix. iScience 2018; 5:69-79. [PMID: 30123887 PMCID: PMC6095676 DOI: 10.1016/j.isci.2018.06.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Peroxisome proliferator activated receptor γ (PPARγ) is a nuclear receptor and target for antidiabetics that increase insulin sensitivity. Owing to the side effects of PPARγ full agonists, research has recently focused on non-activating ligands of PPARγ, which increase insulin sensitivity with decreased side effects. Here, we present the crystal structures of inverse agonist SR10171 and a chemically related antagonist SR11023 bound to the PPARγ ligand-binding domain, revealing an allosteric switch in the activation helix, helix 12 (H12), forming an antagonist conformation in the receptor. H12 interacts with the antagonists to become fixed in an alternative location. Native mass spectrometry indicates that this prevents contacts with coactivator peptides and allows binding of corepressor peptides. Antagonists of related nuclear receptors act to sterically prevent the active configuration of H12, whereas these antagonists of PPARγ alternatively trap H12 in an inactive configuration, which we have termed the tumble and trap mechanism. SR10171 and SR11023 bind PPARγ LBD and “pull” H12 to an antagonist conformation H12 movement is mechanistically distinct from PPARα and other nuclear receptors The antagonist conformation of H12 enables corepressor binding Mechanism of antagonism key to improving T2DM treatments
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Affiliation(s)
- Rebecca L Frkic
- Institute for Photonics and Advanced Sensing (IPAS), School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Andrew C Marshall
- Institute for Photonics and Advanced Sensing (IPAS), School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Anne-Laure Blayo
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Tara L Pukala
- School of Physical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Theodore M Kamenecka
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Patrick R Griffin
- Department of Molecular Medicine, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - John B Bruning
- Institute for Photonics and Advanced Sensing (IPAS), School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia.,Lead Contact
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de la Rosa Rodriguez MA, Sugahara G, Hooiveld GJEJ, Ishida Y, Tateno C, Kersten S. The whole transcriptome effects of the PPARα agonist fenofibrate on livers of hepatocyte humanized mice. BMC Genomics 2018; 19:443. [PMID: 29879903 PMCID: PMC5991453 DOI: 10.1186/s12864-018-4834-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 05/29/2018] [Indexed: 01/08/2023] Open
Abstract
Background The role of PPARα in gene regulation in mouse liver is well characterized. However, less is known about the role of PPARα in human liver. The aim of the present study was to better characterize the impact of PPARα activation on gene regulation in human liver. To that end, chimeric mice containing hepatocyte humanized livers were given an oral dose of 300 mg/kg fenofibrate daily for 4 days. Livers were collected and analyzed by hematoxilin and eosin staining, qPCR, and transcriptomics. Transcriptomics data were compared with existing datasets on PPARα activation in normal mouse liver, human primary hepatocytes, and human precision cut liver slices. Results Of the different human liver models, the gene expression profile of hepatocyte humanized livers most closely resembled actual human liver. In the hepatocyte humanized mouse livers, the human hepatocytes exhibited excessive lipid accumulation. Fenofibrate increased the size of the mouse but not human hepatocytes, and tended to reduce steatosis in the human hepatocytes. Quantitative PCR indicated that induction of PPARα targets by fenofibrate was less pronounced in the human hepatocytes than in the residual mouse hepatocytes. Transcriptomics analysis indicated that, after filtering, a total of 282 genes was significantly different between fenofibrate- and control-treated mice (P < 0.01). 123 genes were significantly lower and 159 genes significantly higher in the fenofibrate-treated mice, including many established PPARα targets such as FABP1, HADHB, HADHA, VNN1, PLIN2, ACADVL and HMGCS2. According to gene set enrichment analysis, fenofibrate upregulated interferon/cytokine signaling-related pathways in hepatocyte humanized liver, but downregulated these pathways in normal mouse liver. Also, fenofibrate downregulated pathways related to DNA synthesis in hepatocyte humanized liver but not in normal mouse liver. Conclusion The results support the major role of PPARα in regulating hepatic lipid metabolism, and underscore the more modest effect of PPARα activation on gene regulation in human liver compared to mouse liver. The data suggest that PPARα may have a suppressive effect on DNA synthesis in human liver, and a stimulatory effect on interferon/cytokine signalling.
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Affiliation(s)
- Montserrat A de la Rosa Rodriguez
- Nutrition, Metabolism and Genomics group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708, WE, Wageningen, The Netherlands
| | - Go Sugahara
- Research and Development Department, PhoenixBio, Co., Ltd, 3-4-1 Kagamiyama, Higashi-, Hiroshima, Japan
| | - Guido J E J Hooiveld
- Nutrition, Metabolism and Genomics group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708, WE, Wageningen, The Netherlands
| | - Yuji Ishida
- Research and Development Department, PhoenixBio, Co., Ltd, 3-4-1 Kagamiyama, Higashi-, Hiroshima, Japan.,Liver Research Project Center, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Chise Tateno
- Research and Development Department, PhoenixBio, Co., Ltd, 3-4-1 Kagamiyama, Higashi-, Hiroshima, Japan.,Liver Research Project Center, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Sander Kersten
- Nutrition, Metabolism and Genomics group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708, WE, Wageningen, The Netherlands.
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Defour M, Dijk W, Ruppert P, Nascimento EBM, Schrauwen P, Kersten S. The Peroxisome Proliferator-Activated Receptor α is dispensable for cold-induced adipose tissue browning in mice. Mol Metab 2018; 10:39-54. [PMID: 29455954 PMCID: PMC5985232 DOI: 10.1016/j.molmet.2018.01.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 01/25/2018] [Accepted: 01/31/2018] [Indexed: 11/23/2022] Open
Abstract
Objective Chronic cold exposure causes white adipose tissue (WAT) to adopt features of brown adipose tissue (BAT), a process known as browning. Previous studies have hinted at a possible role for the transcription factor Peroxisome Proliferator-Activated Receptor alpha (PPARα) in cold-induced browning. Here we aimed to investigate the importance of PPARα in driving transcriptional changes during cold-induced browning in mice. Methods Male wildtype and PPARα−/− mice were housed at thermoneutrality (28 °C) or cold (5 °C) for 10 days. Whole genome expression analysis was performed on inguinal WAT. In addition, other analyses were carried out. Whole genome expression data of livers of wildtype and PPARα−/− mice fasted for 24 h served as positive control for PPARα-dependent gene regulation. Results Cold exposure increased food intake and decreased weight of BAT and WAT to a similar extent in wildtype and PPARα−/− mice. Except for plasma non-esterified fatty acids, none of the cold-induced changes in plasma metabolites were dependent on PPARα genotype. Histological analysis of inguinal WAT showed clear browning upon cold exposure but did not reveal any morphological differences between wildtype and PPARα−/− mice. Transcriptomics analysis of inguinal WAT showed a marked effect of cold on overall gene expression, as revealed by principle component analysis and hierarchical clustering. However, wildtype and PPARα−/− mice clustered together, even after cold exposure, indicating a similar overall gene expression profile in the two genotypes. Pathway analysis revealed that cold upregulated pathways involved in energy usage, oxidative phosphorylation, and fatty acid β-oxidation to a similar extent in wildtype and PPARα−/− mice. Furthermore, cold-mediated induction of genes related to thermogenesis such as Ucp1, Elovl3, Cox7a1, Cox8, and Cidea, as well as many PPAR target genes, was similar in wildtype and PPARα−/− mice. Finally, pharmacological PPARα activation had a minimal effect on expression of cold-induced genes in murine WAT. Conclusion Cold-induced changes in gene expression in inguinal WAT are unaltered in mice lacking PPARα, indicating that PPARα is dispensable for cold-induced browning. Chronic cold markedly induces PPARα expression in inguinal fat. Cold exposure causes transient hypothermia in PPARα−/− mice. Chronic cold-induced changes in gene expression in inguinal fat are unaltered in PPARα−/− mice. Chronic cold does not lead to PPARα activation in liver.
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Affiliation(s)
- Merel Defour
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Wieneke Dijk
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Philip Ruppert
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Emmani B M Nascimento
- Department of Human Biology and Human Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - Patrick Schrauwen
- Department of Human Biology and Human Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, PO Box 616, 6200 MD Maastricht, The Netherlands
| | - Sander Kersten
- Nutrition, Metabolism and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
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9
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Madureira TV, Pinheiro I, de Paula Freire R, Rocha E, Castro LF, Urbatzka R. Genome specific PPARαB duplicates in salmonids and insights into estrogenic regulation in brown trout. Comp Biochem Physiol B Biochem Mol Biol 2017; 208-209:94-101. [PMID: 28414176 DOI: 10.1016/j.cbpb.2017.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/10/2017] [Accepted: 04/10/2017] [Indexed: 02/04/2023]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are key regulators of many processes in vertebrates, such as carbohydrate and lipid metabolism. PPARα, a member of the PPAR nuclear receptor gene subfamily (NR1C1), is involved in fatty acid metabolism, namely in peroxisomal β-oxidation. Two gene paralogues, pparαA and pparαB, were described in several teleost species with their origin dating back to the teleost-specific genome duplication (3R). Given the additional salmonid-specific genome duplication (4R), four genes could be theoretically anticipated for this gene subfamily. In this work, we examined the pparα gene repertoire in brown trout, Salmo trutta f. fario. Data disclosed two pparα-like sequences in brown trout. Phylogenetic analyses further revealed that the isolated genes are most likely genome pparαB duplicates, pparαBa and pparαBb, while pparαA is apparently absent in salmonids. Both genes showed a ubiquitous mRNA expression across a panel of 11 different organs. In vitro exposed primary brown trout hepatocytes strongly suggest that pparα gene paralogues are differently regulated by ethinylestradiol (EE2). PparαBb mRNA expression significantly decreased with dosage, reaching significance after exposure to 50μM EE2, while pparαBa mRNA increased, significant at 1μM EE2. The present data enhances the understanding of pparα function and evolution in teleost, and reinforces the evidence of a potential crosstalk between estrogenic and pparα signaling pathways.
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Affiliation(s)
- Tânia Vieira Madureira
- CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, University of Porto (U.Porto), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal; ICBAS - Institute of Biomedical Sciences Abel Salazar, Department of Microscopy, Laboratory Histology and Embryology, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Ivone Pinheiro
- CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, University of Porto (U.Porto), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal; ICBAS - Institute of Biomedical Sciences Abel Salazar, Department of Microscopy, Laboratory Histology and Embryology, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Rafaelle de Paula Freire
- ICBAS - Institute of Biomedical Sciences Abel Salazar, Department of Microscopy, Laboratory Histology and Embryology, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Eduardo Rocha
- CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, University of Porto (U.Porto), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal; ICBAS - Institute of Biomedical Sciences Abel Salazar, Department of Microscopy, Laboratory Histology and Embryology, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Luis Filipe Castro
- CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, University of Porto (U.Porto), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal; FCUP - Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | - Ralph Urbatzka
- CIIMAR - Interdisciplinary Centre for Marine and Environmental Research, University of Porto (U.Porto), Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4450-208 Matosinhos, Portugal.
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10
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Fulton J, Mazumder B, Whitchurch JB, Monteiro CJ, Collins HM, Chan CM, Clemente MP, Hernandez-Quiles M, Stewart EA, Amoaku WM, Moran PM, Mongan NP, Persson JL, Ali S, Heery DM. Heterodimers of photoreceptor-specific nuclear receptor (PNR/NR2E3) and peroxisome proliferator-activated receptor-γ (PPARγ) are disrupted by retinal disease-associated mutations. Cell Death Dis 2017; 8:e2677. [PMID: 28300834 PMCID: PMC5386588 DOI: 10.1038/cddis.2017.98] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 12/30/2022]
Abstract
Photoreceptor-specific nuclear receptor (PNR/NR2E3) and Tailless homolog (TLX/NR2E1) are human orthologs of the NR2E group, a subgroup of phylogenetically related members of the nuclear receptor (NR) superfamily of transcription factors. We assessed the ability of these NRs to form heterodimers with other members of the human NRs representing all major subgroups. The TLX ligand-binding domain (LBD) did not appear to form homodimers or interact directly with any other NR tested. The PNR LBD was able to form homodimers, but also exhibited robust interactions with the LBDs of peroxisome proliferator-activated receptor-γ (PPARγ)/NR1C3 and thyroid hormone receptor b (TRb) TRβ/NR1A2. The binding of PNR to PPARγ was specific for this paralog, as no interaction was observed with the LBDs of PPARα/NR1C1 or PPARδ/NR1C2. In support of these findings, PPARγ and PNR were found to be co-expressed in human retinal tissue extracts and could be co-immunoprecipitated as a native complex. Selected sequence variants in the PNR LBD associated with human retinopathies, or a mutation in the dimerization region of PPARγ LBD associated with familial partial lipodystrophy type 3, were found to disrupt PNR/PPARγ complex formation. Wild-type PNR, but not a PNR309G mutant, was able to repress PPARγ-mediated transcription in reporter assays. In summary, our results reveal novel heterodimer interactions in the NR superfamily, suggesting previously unknown functional interactions of PNR with PPARγ and TRβ that have potential importance in retinal development and disease.
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Affiliation(s)
- Joel Fulton
- School of Pharmacy, University of Nottingham, Nottingham, UK
| | - Bismoy Mazumder
- School of Pharmacy, University of Nottingham, Nottingham, UK
| | | | | | | | - Chun M Chan
- School of Pharmacy, University of Nottingham, Nottingham, UK
| | | | | | - Elizabeth A Stewart
- Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK
| | - Winfried M Amoaku
- Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK
| | - Paula M Moran
- School of Psychology, University of Nottingham, Nottingham, UK
| | - Nigel P Mongan
- School of Veterinary Medicine and Science, University of Nottingham, Nottingham, UK
- Department of Pharmacology, Weill Cornell Medicine, New York, NY, USA
| | - Jenny L Persson
- Division of Experimental Cancer Research, Department of Translational Medicine, Lund University, Clinical Research Centre, Malmö, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Simak Ali
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - David M Heery
- School of Pharmacy, University of Nottingham, Nottingham, UK
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11
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Al-Kurdi B. Hierarchical transcriptional profile of urothelial cells development and differentiation. Differentiation 2017; 95:10-20. [PMID: 28135607 DOI: 10.1016/j.diff.2016.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 10/09/2016] [Accepted: 10/14/2016] [Indexed: 11/27/2022]
Abstract
The urothelial lining of the lower urinary tract is the most efficient permeability barrier in animals, exhibiting a highly differentiated phenotype and a remarkable regenerative capacity upon wounding. During development and possibly during repair, cells undergo a sequence of hierarchical transcriptional events that mark the transition of these cells from the least differentiated urothelial phenotype characteristic of the basal cell layer, to the most differentiated cellular phenotype characteristic of the superficial cell layer. Unraveling normal urothelial differentiation program is essential to uncover the underlying causes of many congenital abnormalities and for the development of an appropriate differentiation niche for stem cells, for future use in urinary tract tissue engineering and organ reconstruction. Kruppel like factor-5 appears to be at the top of the hierarchy activating several downstream transcription factors, the most prominent of which is peroxisome proliferator activator receptor-γ. Eventually those lead to the activation of transcription factors that directly regulate the expression of uroplakin proteins along with other proteins that mediate the permeability function of the urothelium. In this review, we discuss the most recent findings in the area of urothelial cellular differentiation and transcriptional regulation, aiming for a comprehensive overview that aids in a refined understanding of this process.
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Affiliation(s)
- Ban Al-Kurdi
- Cell Therapy Center, The University of Jordan, Amman, Jordan.
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12
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Saeed A, Hoekstra M, Hoeke MO, Heegsma J, Faber KN. The interrelationship between bile acid and vitamin A homeostasis. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:496-512. [PMID: 28111285 DOI: 10.1016/j.bbalip.2017.01.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 01/04/2017] [Accepted: 01/18/2017] [Indexed: 12/12/2022]
Abstract
Vitamin A is a fat-soluble vitamin important for vision, reproduction, embryonic development, cell differentiation, epithelial barrier function and adequate immune responses. Efficient absorption of dietary vitamin A depends on the fat-solubilizing properties of bile acids. Bile acids are synthesized in the liver and maintained in an enterohepatic circulation. The liver is also the main storage site for vitamin A in the mammalian body, where an intimate collaboration between hepatocytes and hepatic stellate cells leads to the accumulation of retinyl esters in large cytoplasmic lipid droplet hepatic stellate cells. Chronic liver diseases are often characterized by disturbed bile acid and vitamin A homeostasis, where bile production is impaired and hepatic stellate cells lose their vitamin A in a transdifferentiation process to myofibroblasts, cells that produce excessive extracellular matrix proteins leading to fibrosis. Chronic liver diseases thus may lead to vitamin A deficiency. Recent data reveal an intricate crosstalk between vitamin A metabolites and bile acids, in part via the Retinoic Acid Receptor (RAR), Retinoid X Receptor (RXR) and the Farnesoid X Receptor (FXR), in maintaining vitamin A and bile acid homeostasis. Here, we provide an overview of the various levels of "communication" between vitamin A metabolites and bile acids and its relevance for the treatment of chronic liver diseases.
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Affiliation(s)
- Ali Saeed
- Department of Gastroenterology and Hepatology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Institute of Molecular biology & Bio-technology, Bahauddin Zakariya University, Multan, Pakistan.
| | - Mark Hoekstra
- Department of Gastroenterology and Hepatology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
| | - Martijn Oscar Hoeke
- Department of Gastroenterology and Hepatology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
| | - Janette Heegsma
- Department of Gastroenterology and Hepatology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Laboratory Medicine, Center for Liver, Digestive, and Metabolic Diseases, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
| | - Klaas Nico Faber
- Department of Gastroenterology and Hepatology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
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13
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Avci CB, Dodurga Y, Gundogdu G, Caglar HO, Kucukatay V, Gunduz C, Satiroglu-Tufan NL. Regulation of URG4/URGCP and PPARα gene expressions after retinoic acid treatment in neuroblastoma cells. Tumour Biol 2013; 34:3853-7. [PMID: 23821302 DOI: 10.1007/s13277-013-0970-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 06/24/2013] [Indexed: 10/26/2022] Open
Abstract
Neuroblastoma (NB), originating from neural crest cells, is the most common extracranial tumor of childhood. Retinoic acid (RA) which is the biological active form of vitamin A regulates differentiation of NB cells, and RA derivatives have been used for NB treatment. PPARα (peroxisome proliferator-activated receptor) plays an important role in the oxidation of fatty acids, carcinogenesis, and differentiation. URG4/URGCP gene is a proto-oncogene and that overexpression of URG4/URGCP is associated with metastasis and tumor recurrence in osteosarcoma. It has been known that URG4/URGCP gene is an overexpressed gene in hepatocellular carcinoma and gastric cancers. This study aims to detect gene expression patterns of PPARα and URG4/URGCP genes in SH-SY5Y NB cell line after RA treatment. Expressions levels of PPARα and URG4/URGCP genes were analyzed after RA treatment for reducing differentiation in SH-SY5Y NB cell line. To induce differentiation, the cells were treated with 10 μM RA in the dark for 3-10 days. Gene expression of URG4/URGCP and PPARα genes were presented as the yield of polymerase chain reaction (PCR) products from target genes compared with the yield of PCR products from the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene. SH-SY5Y cells possess small processes in an undifferentiated state, and after treatment with RA, the cells developed long neurites, resembling a neuronal phenotype. PPARα gene expression increased in RA-treated groups; URG4/URGCP gene expression decreased in SH-SY5Y cells after RA treatment compared with that in the control cells. NB cell differentiation might associate with PPARα and URG4/URGCP gene expression profile after RA treatment.
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Affiliation(s)
- Cigir Biray Avci
- Department of Medical Biology, School of Medicine, Ege University, Bornova, Izmir, 35100, Turkey,
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14
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Mogilenko DA, Kudriavtsev IV, Shavva VS, Dizhe EB, Vilenskaya EG, Efremov AM, Perevozchikov AP, Orlov SV. Peroxisome proliferator-activated receptor α positively regulates complement C3 expression but inhibits tumor necrosis factor α-mediated activation of C3 gene in mammalian hepatic-derived cells. J Biol Chem 2012; 288:1726-38. [PMID: 23168409 DOI: 10.1074/jbc.m112.437525] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Complement C3 is a pivotal component of three cascades of complement activation. The liver is the main source of C3 in circulation and expression and secretion of C3 by hepatocytes is increased during acute inflammation. However, the mechanism of the regulation of the C3 gene in hepatocytes is not well elucidated. We showed that the C3 gene is the direct target for peroxisome proliferator-activated receptor α (PPARα) in human hepatoma HepG2 cells and mouse liver. Using PPARα siRNA and synthetic PPARα agonist WY-14643 and antagonist MK886 we showed that activation of PPARα results in up-regulation of C3 gene expression and protein secretion by HepG2 cells. The PPAR response element (PPRE), which is able to bind PPARα in vitro and in vivo, was found in the human C3 promoter. PPRE is conserved between human and mouse, and WY-14643 stimulates mouse C3 expression in the liver. TNFα increases C3 gene via NF-κB and, to a lesser extent, MEK1/2 signaling pathways, whereas TNFα-mediated stimulation of C3 protein secretion depends on activation of MEK1/2, p38, and JNK in HepG2 cells. Activation of PPARα abolishes TNFα-mediated up-regulation of C3 gene expression and protein secretion due to interference with NF-κB via PPRE-dependent mechanism in HepG2 cells. TNFα decreases PPARα protein content via NF-κB and MEK1/2 signaling pathways and inhibits PPARα binding with the human C3 promoter in HepG2 cells. These results suggest novel mechanism controlling C3 expression in hepatocytes during acute phase inflammation and demonstrate a crosstalk between PPARα and TNFα in the regulation of complement system.
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Affiliation(s)
- Denis A Mogilenko
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg 197376, Russia.
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15
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Treacy MP, Hurst TP. The case for intraocular delivery of PPAR agonists in the treatment of diabetic retinopathy. BMC Ophthalmol 2012; 12:46. [PMID: 22937835 PMCID: PMC3532122 DOI: 10.1186/1471-2415-12-46] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 08/29/2012] [Indexed: 01/17/2023] Open
Abstract
Background Systemic therapeutics targeting the peroxisome proliferator-activated receptors have been found to be beneficial in the treatment of diabetic retinopathy. In this paper, we provide a rationale for the use of these therapeutics as intraocular agents. In addition, we introduce the peroxisome proliferator-activated receptors and describe their functions in response to the drugs. Discussion Based on the evidence of large-scale clinical studies investigating the systemic administration of fenofibrate, this ligand for peroxisome proliferator-activated receptor-α is potentially a good candidate for intraocular delivery. Here, we describe the mechanisms by which it might be acting to improve diabetic retinopathy, its relative safety and we speculate on how it could be developed for intraocular delivery. Summary In this paper, we provide a rationale for the further investigation of peroxisome proliferator-activated receptor-α agonists as intraocular agents for the treatment of diabetic retinopathy.
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Affiliation(s)
- Maxwell P Treacy
- Royal Victoria Eye and Ear Hospital, Adelaide Road, Dublin 2, Dublin, Ireland.
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16
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Activation of Penile Proadipogenic Peroxisome Proliferator-Activated Receptor gamma with an Estrogen: Interaction with Estrogen Receptor Alpha during Postnatal Development. PPAR Res 2011; 2008:651419. [PMID: 18769493 PMCID: PMC2519140 DOI: 10.1155/2008/651419] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Accepted: 07/14/2008] [Indexed: 01/17/2023] Open
Abstract
Exposure to the estrogen receptor alpha (ERα) ligand diethylstilbesterol (DES) between neonatal days 2 to 12 induces penile adipogenesis and adult infertility in rats. The objective of this study was to investigate the in vivo interaction between DES-activated ERα and the proadipogenic transcription factor peroxisome proliferator-activated receptor gamma (PPARγ). Transcripts for PPARs α, β, and γ and γ1a splice variant were detected in Sprague-Dawley normal rat penis with PPARγ predominating. In addition, PPARγ1b and PPARγ2 were newly induced by DES. The PPARγ transcripts were significantly upregulated with DES and reduced by antiestrogen ICI 182, 780. At the cellular level, PPARγ protein was detected in urethral transitional epithelium and stromal, endothelial, neuronal, and smooth muscular cells. Treatment with DES activated ERα and induced adipocyte differentiation in corpus cavernosum penis. Those adipocytes exhibited strong nuclear PPARγ expression. These results suggest a biological overlap between PPARγ and ERα and highlight a mechanism for endocrine disruption.
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17
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Koppen A, Kalkhoven E. Brown vs white adipocytes: The PPARγ coregulator story. FEBS Lett 2010; 584:3250-9. [DOI: 10.1016/j.febslet.2010.06.035] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 06/21/2010] [Accepted: 06/22/2010] [Indexed: 11/30/2022]
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18
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New troglitazone derivatives devoid of PPARγ agonist activity display an increased antiproliferative effect in both hormone-dependent and hormone-independent breast cancer cell lines. Breast Cancer Res Treat 2010; 124:101-10. [PMID: 20054646 DOI: 10.1007/s10549-009-0700-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Accepted: 12/16/2009] [Indexed: 01/10/2023]
Abstract
Numerous recent studies indicate that most anticancer effects of PPARγ agonists like thiazolidinediones are the result of PPARγ-independent pathways. These conclusions were obtained by several approaches including the use of thiazolidinedione derivatives like Δ2-Troglitazone (Δ2-TGZ) that does not activate PPARγ. Since biotinylation has been proposed as a mechanism able to increase the specificity of drug delivery to cancer cells which could express a high level of vitamin receptor, a biotinylated derivative of Δ2-TGZ (bΔ2-TGZ) has been synthetized. In the present article, we have studied the in vitro effects of this molecule on both hormone-dependent (MCF-7) and hormone-independent (MDA-MB-231) breast cancer cells. In both cell lines, bΔ2-TGZ was more efficient than Δ2-TGZ to decrease cell viability. bΔ2-TGZ was also more potent than Δ2-TGZ to induce the proteasomal degradation of cyclin D1 in both cell lines and those of ERα in MCF-7 cells. However, in competition experiments, the presence of free biotin in the culture medium did not decrease the antiproliferative action of bΔ2-TGZ. Besides, other compounds that had no biotin but that were substituted at the same position of the phenolic group of the chromane moiety of Δ2-TGZ decreased cell viability similarly to bΔ2-TGZ. Hence, we concluded that the increased antiproliferative action of bΔ2-TGZ was not due to biotin itself but to the functionalization of the terminal hydroxyl group. This should be taken into account for the design of new thiazolidinedione derivatives able to affect not only hormone-dependent but also hormone-independent breast cancer cells in a PPARγ-independent pathway.
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19
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Garcia-Bates TM, Baglole CJ, Bernard MP, Murant TI, Simpson-Haidaris PJ, Phipps RP. Peroxisome proliferator-activated receptor gamma ligands enhance human B cell antibody production and differentiation. THE JOURNAL OF IMMUNOLOGY 2009; 183:6903-12. [PMID: 19915048 DOI: 10.4049/jimmunol.0900324] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Protective humoral immune responses critically depend on the optimal differentiation of B cells into Ab-secreting cells. Because of the important role of Abs in fighting infections and in successful vaccination, it is imperative to identify mediators that control B cell differentiation. Activation of B cells through TLR9 by CpG-DNA induces plasma cell differentiation and Ab production. Herein, we examined the role of the peroxisome proliferator-activated receptor (PPAR)gamma/RXRalpha pathway on human B cell differentiation. We demonstrated that activated B cells up-regulate their expression of PPARgamma. We also show that nanomolar levels of natural (15-deoxy-Delta(12,14)-prostaglandin J(2)) or synthetic (rosiglitazone) PPARgamma ligands enhanced B cell proliferation and significantly stimulated plasma cell differentiation and Ab production. Moreover, the addition of GW9662, a specific PPARgamma antagonist, abolished these effects. Retinoid X receptor (RXR) is the binding partner for PPARgamma and is required to produce an active transcriptional complex. The simultaneous addition of nanomolar concentrations of the RXRalpha ligand (9-cis-retinoic acid) and PPARgamma ligands to CpG-activated B cells resulted in additive effects on B cell proliferation, plasma cell differentiation, and Ab production. Furthermore, PPARgamma ligands alone or combined with 9-cis-retinoic acid enhanced CpG-induced expression of Cox-2 and the plasma cell transcription factor BLIMP-1. Induction of these important regulators of B cell differentiation provides a possible mechanism for the B cell-enhancing effects of PPARgamma ligands. These new findings indicate that low doses of PPARgamma/RXRalpha ligands could be used as a new type of adjuvant to stimulate Ab production.
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Affiliation(s)
- Tatiana M Garcia-Bates
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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20
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Mansouri RM, Baugé E, Staels B, Gervois P. Systemic and distal repercussions of liver-specific peroxisome proliferator-activated receptor-alpha control of the acute-phase response. Endocrinology 2008; 149:3215-23. [PMID: 18325987 DOI: 10.1210/en.2007-1339] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The acute-phase response is characterized by the modulation of liver expression of many proteins involved in a diversity of biological functions. Among them, some are associated with the pathology of atherosclerosis. We previously found that peroxisome proliferator-activated receptor-alpha (PPARalpha) agonists attenuate the IL-6 induction of acute-phase response gene expression in vitro and in vivo. In the current work, we found a PPARalpha-dependent regulation of hepatic acute-phase response stimulated by IL-1. We also found that IL-1-stimulated expression of secondary wave cytokines such as IL-6 is prevented upon PPARalpha activation in liver. Direct involvement of hepatic PPARalpha was demonstrated using a liver-restricted expression of PPARalpha in mice. IL-1- or IL-6-mediated acute-phase response was inhibited by fenofibrate treatment in liver-specific PPARalpha-expressing mice but not in PPARalpha-deficient mice. In addition, we demonstrated that PPARalpha exerts a general control of the acute-phase response by using an inflammation/infection model of lipopolysaccharide. In such a context, liver-specific PPARalpha-expressing mice displayed lower circulating levels of TNF, IL-1, and IL-6 cytokines. We found a distal repercussion of this lowering at the vascular wall level as illustrated by a decreased expression of adhesion molecules in aorta. In conclusion, we demonstrated that through a specific liver action, PPARalpha behaves as a modulator of systemic inflammation and of the associated vascular response.
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Affiliation(s)
- Roxane M Mansouri
- Institut Pasteur de Lille, Département d'Athérosclérose, and Institut National de la Santé et de la Recherche Médicale Unité 545, Lille F59019, France
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21
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Wilkinson AS, Monteith GR, Shaw PN, Lin CN, Gidley MJ, Roberts-Thomson SJ. Effects of the mango components mangiferin and quercetin and the putative mangiferin metabolite norathyriol on the transactivation of peroxisome proliferator-activated receptor isoforms. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:3037-3042. [PMID: 18393431 DOI: 10.1021/jf800046n] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Mangos are a source of bioactive compounds with potential health-promoting activity. This study evaluated the abilities of the mango components quercetin and mangiferin and the aglycone derivative of mangiferin, norathyriol, to modulate the transactivation of peroxisome proliferator-activated receptor isoforms (PPARs). PPARs are transcription factors important in many human diseases. Through the use of a gene reporter assay it was shown that quercetin inhibited the activation of all three isoforms of PPARs (PPARgamma IC(50) = 56.3 microM; PPARalpha IC(50) = 59.6 microM; PPARbeta IC(50) = 76.9 microM) as did norathyriol (PPARgamma IC(50) = 153.5 microM; PPARalpha IC(50) = 92.8 microM; PPARbeta IC(50) = 102.4 microM), whereas mangiferin did not inhibit the transactivation of any isoform. These findings suggest that mango components and metabolites may alter transcription and could contribute to positive health benefits via this or similar mechanisms.
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Affiliation(s)
- Ashley S Wilkinson
- School of Pharmacy and Centre for Nutrition and Food Sciences, University of Queensland, Brisbane, QLD 4072, Australia
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22
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Disruption of ERalpha signalling pathway by PPARgamma agonists: evidences of PPARgamma-independent events in two hormone-dependent breast cancer cell lines. Breast Cancer Res Treat 2008; 112:437-51. [PMID: 18204896 DOI: 10.1007/s10549-007-9886-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Accepted: 12/26/2007] [Indexed: 01/09/2023]
Abstract
Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor that can be activated by natural ligands such as 15-deoxy-delta(12,14)-prostaglandin J2 (15d-PGJ(2)) as well as synthetic drugs such as thiazolidinediones. The treatment of human breast cancer cell lines with PPARgamma agonists is known to have antiproliferative effects but the role of PPARgamma activation in the process remains unclear. In the present study, we investigated the effects of four PPARgamma agonists, Rosiglitazone (RGZ), Ciglitazone (CGZ), Troglitazone (TGZ) and the natural agonist 15d-PGJ(2), on estrogen receptor alpha (ERalpha) signalling pathway in two hormone-dependent breast cancer cell lines, MCF-7 and ZR-75-1. In both of them, TGZ, CGZ and 15d-PGJ(2) induced an inhibition of ERalpha signalling associated with the proteasomal degradation of ERalpha. ZR-75-1 cells were more sensitive than MCF-7 cells to these compounds. Treatments that induced ERalpha degradation inhibited cell proliferation after 24 h. In contrast, 24 h exposure to RGZ, the most potent activator of PPARgamma disrupted neither ERalpha signalling nor cell proliferation. 9-cis retinoic acid never potentiated the proteasomal degradation of ERalpha. PPARgamma antagonists (T0070907, BADGE and GW 9662) did not block the proteolysis of ERalpha in MCF-7 and ZR-75-1 cells treated with TGZ. ERalpha proteolysis still occurred in case of PPARgamma silencing as well as in case of treatment with the PPARgamma-inactive compound Delta2-TGZ, demonstrating a PPARgamma-independent mechanism. The use of thiazolidinedione derivatives able to trigger ERalpha degradation by a PPARgamma-independent pathway could be an interesting tool for breast cancer therapy.
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Pascual G, Ricote M, Hevener AL. Macrophage peroxisome proliferator activated receptor γ as a therapeutic target to combat Type 2 diabetes. Expert Opin Ther Targets 2007; 11:1503-20. [DOI: 10.1517/14728222.11.11.1503] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Mettu NB, Stanley TB, Dwyer MA, Jansen MS, Allen JE, Hall JM, McDonnell DP. The Nuclear Receptor-Coactivator Interaction Surface as a Target for Peptide Antagonists of the Peroxisome Proliferator-Activated Receptors. Mol Endocrinol 2007; 21:2361-77. [PMID: 17595321 DOI: 10.1210/me.2007-0201] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
AbstractThe peroxisome proliferator-activated receptors (PPARα, PPARδ, and PPARγ) constitute a family of nuclear receptors that regulates metabolic processes involved in lipid and glucose homeostasis. Although generally considered to function as ligand-regulated receptors, all three PPARs exhibit a high level of constitutive activity that may result from their stimulation by intracellularly produced endogenous ligands. Consequently, complete inhibition of PPAR signaling requires the development of inverse agonists. However, the currently available small molecule antagonists for the PPARs function only as partial agonists, or their efficacy is not sufficient to inhibit the constitutive activity of these receptors. Due to the lack of efficacious antagonists that interact with the ligand-binding domain of the PPARs, we decided to target an interaction that is central to nuclear receptor-mediated gene transcription: the nuclear receptor-coactivator interaction. We utilized phage display technology to identify short LXXLL-containing peptides that bind to the PPARs. Analysis of these peptides revealed a consensus binding motif consisting of HPLLXXLL. Cross-screening of these peptides for binding to other nuclear receptors enabled the identification of a high-affinity PPAR-selective peptide that has the ability to repress PPARγ1-dependent transcription of transfected reporter genes. Most importantly, when introduced into HepG2 cells, the peptide inhibited the expression of endogenous PPARγ1 target genes, adipose differentiation-related protein and mitochondrial 3-hydroxy-3-methylglutaryl coenzyme A synthase 2. This work lends support for the rational development of peptidomimetics that block receptor-mediated transcription by targeting the nuclear receptor-coactivator interaction surface.
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Affiliation(s)
- Niharika B Mettu
- Duke University Medical Center, Department of Pharmacology and Cancer Biology, Box 3813, Durham, North Carolina 27710, USA
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Talbert DR, Allred CD, Zaytseva YY, Kilgore MW. Transactivation of ERalpha by Rosiglitazone induces proliferation in breast cancer cells. Breast Cancer Res Treat 2007; 108:23-33. [PMID: 17453334 DOI: 10.1007/s10549-007-9575-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Accepted: 03/16/2007] [Indexed: 10/23/2022]
Abstract
In the present study, we demonstrate that Rosiglitazone (Rosi), a thiazolidinedione and PPARgamma agonist, induces ERE (Estrogen Receptor Response Element) reporter activity, pS2 (an endogenous ER gene target) expression, and proliferation of ER positive breast cancer (MCF-7) cells. By performing a dose-response assay, we determined that high concentrations of Rosi inhibit proliferation, while low concentrations of Rosi induce proliferation. Using the anti-estrogen ICI, ER negative breast cancer (MDA-MB-231) cells, and a prostate cancer cell line (22Rv1) deficient in both ERalpha and PPARgamma, we determined that Rosiglitazone-induced ERE reporter activation and proliferation is through an ERalpha dependent mechanism. Rosiglitazone-induced ERE activation is also dependent on activation of the Extracellular Signal-Regulated Kinase-Mitogen Activated Protein Kinase (ERK-MAPK) pathway, since it is inhibited by co-treatment with U0126, a specific inhibitor of this pathway. We also demonstrate that when ERalpha and PPARgamma are both present, they compete for Rosi, inhibiting each others transactivation. To begin to unravel the pharmacological mechanism of Rosi-induced ER activation, sub-maximally effective concentrations of E(2) were used in combination with increasing concentrations of Rosi in luciferase reporter assays. From these assays it appears that E(2) and Rosi both activate ERalpha via similar pharmacological mechanisms. Furthermore sub-maximally effective concentrations of E(2) and Rosi additively increase both ERE reporter activity and MCF-7 cell proliferation. The results of this study may have clinical relevancy for Rosi's use both as an anti-diabetic in post-menopausal women and as an anti-cancer drug in women with ER positive breast cancer.
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Affiliation(s)
- Dominique R Talbert
- Department of Molecular and Biomedical Pharmacology, University of Kentucky College of Medicine, MS 305, Chandler Medical Center, Lexington, KY 40536, USA
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26
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Chow EKH, Razani B, Cheng G. Innate immune system regulation of nuclear hormone receptors in metabolic diseases. J Leukoc Biol 2007; 82:187-95. [PMID: 17314330 DOI: 10.1189/jlb.1206741] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The immune system modulates a number of biological processes to properly defend against pathogens. Here, we review how crosstalk between nuclear hormone receptors and the innate immune system may influence multiple biological functions during an immune response. Although nuclear hormone receptor repression of innate immune responses and inflammation has been well studied, a number of new studies have identified repression of nuclear hormone receptor signaling by various innate immune responses. IFN regulatory factor 3, a key transcription factor involved in the induction of antiviral genes, may play a role in mediating such crosstalk between the innate immune response and nuclear receptor-regulated metabolism. This crosstalk mechanism is now implicated in the pathogenesis of atherosclerosis and Reye's syndrome and could provide an explanation for other pathogen-associated metabolic and developmental disorders.
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Affiliation(s)
- Edward Kai-Hua Chow
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, California 90095, USA
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Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors involved in the transcriptional regulation of key metabolic pathways such as lipid metabolism, adipogenesis, and insulin sensitivity. More recent work implicates all 3 PPAR isotypes (alpha, gamma, and delta, also known as beta or beta/delta) in inflammatory and atherosclerotic pathways. Because these nuclear receptors are activated by extracellular signals and control multiple gene targets, PPARs can be seen as nodes that control multiple inputs and outputs involved in energy balance, providing insight into how metabolism and the vasculature may be integrated. The ongoing clinical use of fibrates, which activate PPARalpha, and thiazolidinediones, which activate PPARgamma, establishes these receptors as viable drug targets, whereas considerable in vitro animal model and human surrogate marker studies suggest that PPAR activation may limit inflammation and atherosclerosis. Together, these various observations have stimulated intense interest in PPARs as therapeutic targets and led to large-scale cardiovascular end-point trials with PPAR agonists. The first of these studies has generated mixed results that require careful review, especially in anticipation of additional clinical trial data and ongoing attempts to develop novel PPAR modulators. Such analysis of the existing PPAR data, the appropriate use of currently approved PPAR agonists, and continued progress in PPAR therapeutics will be predicated on a better understanding of PPAR biology.
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Affiliation(s)
- Jonathan D Brown
- Cardiovascular Division, Brigham and Women's Hospital, Boston, Mass, USA
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Chow EK, Castrillo A, Shahangian A, Pei L, O'Connell RM, Modlin RL, Tontonoz P, Cheng G. A role for IRF3-dependent RXRalpha repression in hepatotoxicity associated with viral infections. J Exp Med 2006; 203:2589-602. [PMID: 17074929 PMCID: PMC2118146 DOI: 10.1084/jem.20060929] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 10/04/2006] [Indexed: 12/18/2022] Open
Abstract
Viral infections and antiviral responses have been linked to several metabolic diseases, including Reye's syndrome, which is aspirin-induced hepatotoxicity in the context of a viral infection. We identify an interferon regulatory factor 3 (IRF3)-dependent but type I interferon-independent pathway that strongly inhibits the expression of retinoid X receptor alpha (RXRalpha) and suppresses the induction of its downstream target genes, including those involved in hepatic detoxification. Activation of IRF3 by viral infection in vivo greatly enhances bile acid- and aspirin-induced hepatotoxicity. Our results provide a critical link between the innate immune response and host metabolism, identifying IRF3-mediated down-regulation of RXRalpha as a molecular mechanism for pathogen-associated metabolic diseases.
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Affiliation(s)
- Edward K Chow
- Molecular Biology Institute, Department of Pathology and Laboratory Medicine, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
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VARLEY CLAIREL, GARTHWAITE MARYA, CROSS WILLIAM, HINLEY JENNIFER, TREJDOSIEWICZ LUDWIKK, SOUTHGATE JENNIFER. PPARgamma-regulated tight junction development during human urothelial cytodifferentiation. J Cell Physiol 2006; 208:407-17. [PMID: 16688762 PMCID: PMC1522040 DOI: 10.1002/jcp.20676] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Urothelial barrier function is maintained by apical membrane plaques and intercellular tight junctions (TJ). Little is known about the composition and regulation of TJ expression in human urothelium. In this study, we have characterised the expression of TJ components in situ and their regulation in an in vitro model of differentiating normal human urothelial (NHU) cells. In normal ureteric urothelium in situ, there was a differentiation-associated profile of claudins 3, 4, 5, 7, ZO1 and occludin proteins. Proliferating NHU cells in vitro expressed predominantly claudin 1 protein and transcripts for claudins 1-5 and 7. Following induction of differentiation by pharmacological activation of PPARgamma and blockade of EGFR, there was de novo expression of claudin 3 mRNA and protein and downregulation of claudin 2 transcription. There was also a massive increase in expression of claudin 4 and 5 proteins which was due to inhibition of proteasomal degradation of claudin 4 and consequential stabilisation of the claudin 5 heterodimerisation partner. NHU cell differentiation was accompanied by relocalisation of TJ proteins to intercellular junctions. The differentiation-associated development of TJ formation in vitro reflected the stage-related TJ expression seen in situ. This was distinct from changes in TJ composition of NHU cells mediated by increasing the calcium concentration of the medium. Our results imply a role for PPARgamma and EGFR signalling pathways in regulating TJ formation in NHU cells and support the hypothesis that TJ development is an integral part of the urothelial differentiation programme.
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Affiliation(s)
- CLAIRE L. VARLEY
- Jack Birch Unit of Molecular Carcinogenesis, Department of Biology, University of York, United Kingdom
| | - MARY A.E. GARTHWAITE
- Jack Birch Unit of Molecular Carcinogenesis, Department of Biology, University of York, United Kingdom
- Pyrah Department of Urology, St. James’s University Hospital, United Kingdom
| | - WILLIAM CROSS
- Jack Birch Unit of Molecular Carcinogenesis, Department of Biology, University of York, United Kingdom
- Pyrah Department of Urology, St. James’s University Hospital, United Kingdom
| | - JENNIFER HINLEY
- Jack Birch Unit of Molecular Carcinogenesis, Department of Biology, University of York, United Kingdom
| | - LUDWIK K. TREJDOSIEWICZ
- Leeds Institute of Molecular Medicine (LIMM), St. James’s University Hospital, United Kingdom
| | - JENNIFER SOUTHGATE
- Jack Birch Unit of Molecular Carcinogenesis, Department of Biology, University of York, United Kingdom
- *Correspondence to: Jennifer Southgate, Jack Birch Unit of Molecular Carcinogenesis, Department of Biology, University of York, York YO10 5YW, UK. E-mail:
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Venkata NG, Robinson JA, Cabot PJ, Davis B, Monteith GR, Roberts-Thomson SJ. Mono(2-ethylhexyl)phthalate and mono-n-butyl phthalate activation of peroxisome proliferator activated-receptors alpha and gamma in breast. Toxicol Lett 2005; 163:224-34. [PMID: 16326050 DOI: 10.1016/j.toxlet.2005.11.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Revised: 11/02/2005] [Accepted: 11/02/2005] [Indexed: 11/17/2022]
Abstract
The phthalates di(2-ethylhexyl)phthalate (DEHP) and di-n-butyl phthalate (DBP) are environmental contaminants with significant human exposures. Both compounds are known reproductive toxins in rodents and DEHP also induces rodent hepatocarcinogenesis in a process believed to be mediated via the peroxisome proliferator-activated receptor alpha (PPARalpha). DEHP and DBP are metabolised to their respective monoesters, mono-(2-ethylhexyl)phthalate (MEHP) and mono-n-butyl phthalate (MBP), which are the active metabolites. MEHP also activates another member of the PPAR subfamily, PPARgamma. The effects of PPARalpha and PPARgamma activation in human breast cells appears to be opposing; PPARalpha activators in breast cells cause an increase in proliferation, while PPARgamma activation in breast cells is associated with differentiation and an inhibition of cell proliferation. Further to this the activation of the PPARs is cell and ligand specific, suggesting the importance of examining the effect of MEHP and MBP on the activation of PPARalpha, PPARbeta and PPARgamma in human breast. We used the common model of human breast cancer MCF-7 and examined the ability of MEHP and MBP to activate human PPARs in this system. The ability of MBP and MEHP to block PPAR responses was also assessed. We found that both human PPARalpha and PPARgamma were activated by MEHP whereas MEHP could not activate PPARbeta. MBP was unable to activate any PPAR isoforms in this breast model, despite being a weak peroxisome proliferator in liver, although MBP was an antagonist for both PPARgamma and PPARbeta. Our results suggest that the toxicological consequences of MEHP in the breast could be complex given the opposing effects of PPARalpha and PPARgamma in human breast cells.
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Guo L, Tabrizchi R. Peroxisome proliferator-activated receptor gamma as a drug target in the pathogenesis of insulin resistance. Pharmacol Ther 2005; 111:145-73. [PMID: 16305809 DOI: 10.1016/j.pharmthera.2005.10.009] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Accepted: 10/03/2005] [Indexed: 01/08/2023]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that belong to the nuclear hormone receptor superfamily. The activation of PPAR-gamma, an isotype of PPARs, can either increase or decrease the transcription of target genes. The genes controlled by this form of PPAR have been shown to encode proteins or peptides that participate in the pathogenesis of insulin resistance. Insulin resistance is defined as a state of reduced responsiveness to normal circulating concentrations of insulin and it often co-exists with central obesity, hypertension, dyslipidemia, and atherosclerosis. There is substantial evidence that links obesity with insulin resistance and type-2 diabetes. The early phase of obesity-related insulin resistance has 2 components: (a) interruption of lipid homeostasis leading to the increased plasma concentration of fatty acids that is normally suppressed by the activation of PPAR-gamma, and (b) activation of factors such as cytokines depressed by PPAR-gamma that cause insulin resistance. Therefore, it is logical to suggest that activation of PPAR-gamma may partially reverse the state of insulin resistance. Evidently, activation of the nuclear receptor, PPAR-gamma, by thiazolidinediones has been reported to ameliorate insulin resistance. Although hepatotoxity and possibility to induce congestive heart failure (CHF) limit the widely use of thiazolodinediones, they are still powerful weapon to fight against insulin resistance and type-2 diabetes if use properly. This article reviews the physiology of PPAR-gamma and insulin-signaling transduction, the pathogenesis of insulin resistance in obesity-related type-2 diabetes, the pharmacological role of PPAR-gamma in insulin resistance, and additional effects of thiazolidinediones.
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Affiliation(s)
- Liang Guo
- Division of Basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada A1B 3V6
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32
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Stahlschmidt J, Varley CL, Toogood G, Selby PJ, Southgate J. Urothelial differentiation in chronically urine-deprived bladders of patients with end-stage renal disease. Kidney Int 2005; 68:1032-40. [PMID: 16105033 DOI: 10.1111/j.1523-1755.2005.00495.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND It is unknown whether normal bladder voiding function, or soluble factors present in urine, contribute to the maturation and maintenance of the differentiated state of the uroepithelial cell lining of the lower urinary tract. METHODS We used the urothelium of anuric patients on long-term hemodialysis, sampled at the time of renal transplantation, to investigate the expression of urothelial differentiation-associated antigens, including uroplakins (UPIa, UPIb, UPII, and UPIIIa), cytokeratin isotypes (CK7, CK8, CK13, CK14, CK17, CK18, and CK20), nuclear hormone receptors [peroxisome proliferators activated receptor-gamma (PPAR-gamma) and retinoid X receptor-alpha (RXR-alpha)], and a cell cycle marker (Ki-67). To determine whether urinary metabolites of the arachidonic pathway could induce urothelial differentiation, cultured normal human urothelial (NHU) cells were treated with 15-deoxy-delta12, 14-prostaglandin J2 (15d-PGJ2) and prostaglandin J2 (PGJ2). The expression levels of the markers of differentiation, the uroplakins, were assessed by ribonuclease protection assay. Results. When compared in a blinded analysis against control normal urothelium, no significant changes were found in the expression or localization patterns of any of the antigens studied in the anuric patients. Furthermore, neither 15d-PGJ2 nor PGJ2 were able to induce expression of the UPII gene in NHU cells, in contrast to cultures exposed to the pharmacologic PPAR-gamma agonist, troglitazone. Conclusion. These data provide prima facie evidence that exogenous urine-derived factors do not modulate the differentiation program in urothelium, suggesting that other urothelial- or serum-derived factors are likely to be involved. These findings are important in understanding post-developmental maturation and functional relationships in urologic tissues of the adult organism.
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Affiliation(s)
- Jens Stahlschmidt
- Jack Birch Unit of Molecular Carcinogenesis, Department of Biology, University of York, York, United Kingdom
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Bonofiglio D, Gabriele S, Aquila S, Catalano S, Gentile M, Middea E, Giordano F, Andò S. Estrogen receptor alpha binds to peroxisome proliferator-activated receptor response element and negatively interferes with peroxisome proliferator-activated receptor gamma signaling in breast cancer cells. Clin Cancer Res 2005; 11:6139-47. [PMID: 16144913 DOI: 10.1158/1078-0432.ccr-04-2453] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
PURPOSE The molecular mechanisms involved in the repressive effects exerted by estrogen receptors (ER) on peroxisome proliferator-activated receptor (PPAR) gamma-mediated transcriptional activity remain to be elucidated. The aim of the present study was to provide new insight into the crosstalk between ERalpha and PPARgamma pathways in breast cancer cells. EXPERIMENTAL DESIGN Using MCF7 and HeLa cells as model systems, we did transient transfections and electrophoretic mobility shift assay and chromatin immunoprecipitation studies to evaluate the ability of ERalpha to influence PPAR response element-mediated transcription. A possible direct interaction between ERalpha and PPARgamma was ascertained by co-immunoprecipitation assay, whereas their modulatory role in the phosphatidylinositol 3-kinase (PI3K)/AKT pathway was evaluated by determining PI3K activity and AKT phosphorylation. As a biological counterpart, we investigated the growth response to the cognate ligands of both receptors in hormone-dependent MCF7 breast cancer cells. RESULTS Our data show for the first time that ERalpha binds to PPAR response element and represses its transactivation. Moreover, we have documented the physical and functional interactions of ERalpha and PPARgamma, which also involve the p85 regulatory subunit of PI3K. Interestingly, ERalpha and PPARgamma pathways have an opposite effect on the regulation of the PI3K/AKT transduction cascade, explaining, at least in part, the divergent response exerted by the cognate ligands 17beta-estradiol and BRL49653 on MCF7 cell proliferation. CONCLUSION ERalpha physically associates with PPARgamma and functionally interferes with PPARgamma signaling. This crosstalk could be taken into account in setting new pharmacologic strategies for breast cancer disease.
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Smith SA, Monteith GR, Robinson JA, Venkata NG, May FJ, Roberts-Thomson SJ. Effect of the peroxisome proliferator-activated receptor beta activator GW0742 in rat cultured cerebellar granule neurons. J Neurosci Res 2004; 77:240-9. [PMID: 15211590 DOI: 10.1002/jnr.20153] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The ligand-activated transcription factor peroxisome proliferator-activated receptor beta (PPARbeta) is present in the brain and is implicated in the regulation of genes with potential roles in neurotoxicity. We sought to examine the role of PPARbeta in neuronal cell death by using the PPARbeta ligand GW0742. Primary cultures of rat cerebellar granule neurons were prepared from 7-day-old pups. Reverse transcriptase-polymerase chain reaction and in situ hybridization were used to verify that PPARbeta mRNA was present in neurons. After 10-12 days in culture, the neuronal cells were incubated in the presence of GW0742, and cell death was measured with a lactate dehydrogenase release (LDH) assay. After 24 hr of exposure, PPARbeta activation by GW0742 was not inherently toxic to cerebellar granule neurons. However, toxicity was observed after 48 hr, with cell death mediated via an apoptotic mechanism. In an effect opposite to that observed with PPARalpha-activating ligands, PPARbeta activation exhibited neuroprotective properties. Treatment with GW0742 significantly reduced cell death during a 12-hr exposure to low-KCl media. These results clearly reinforce very specific roles for the PPAR isoforms in neurons and suggest that PPARbeta is worthy of further investigation regarding its potential role as a therapeutic target in neurodegenerative states.
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Affiliation(s)
- Steven A Smith
- School of Pharmacy, The University of Queensland, St. Lucia, Queensland, Australia
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Moreno S, Farioli-Vecchioli S, Cerù MP. Immunolocalization of peroxisome proliferator-activated receptors and retinoid x receptors in the adult rat CNS. Neuroscience 2004; 123:131-45. [PMID: 14667448 DOI: 10.1016/j.neuroscience.2003.08.064] [Citation(s) in RCA: 454] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Peroxisome proliferator-activated and retinoid X receptors (PPARs and RXRs) are transcription factors belonging to the steroid hormone receptor superfamily. Upon activation by their ligands, PPARs and RXRs bind to their target genes as heterodimers. Ligands of these receptors include lipophylic molecules, such as retinoids, fatty acids and eicosanoids, the importance of which in the metabolism and functioning of the nervous tissue is well documented. The immunohistochemical distribution of PPARs and RXRs in the CNS of the adult rat was studied by means of a sensitive biotinyl-tyramide method. All PPAR (alpha, beta/delta and gamma) and RXR (alpha, beta and gamma) isotypes were detected and found to exhibit specific patterns of localization in the different areas of the brain and spinal cord. The presence of the nuclear receptors was observed in both neuronal and glial cells. While PPAR beta/delta and RXR beta showed a widespread distribution, alpha and gamma isotypes exhibited a more restricted pattern of expression. The frontal cortex, basal ganglia, reticular formation, some cranial nerve nuclei, deep cerebellar nuclei, and cerebellar Golgi cells appeared rather rich in all studied receptors. Based on our data, we suggest that in the adult CNS, PPARs and RXRs, besides playing roles common to many other tissues, may have specific functions in regulating the expression of genes involved in neurotransmission, and therefore play roles in complex processes, such as aging, neurodegeneration, learning and memory.
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Affiliation(s)
- S Moreno
- Department of Biology-LIME, University Roma Tre, Rome, Italy
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Smith SA, Monteith GR, Holman NA, Robinson JA, May FJ, Roberts-Thomson SJ. Effects of peroxisome proliferator-activated receptor gamma ligands ciglitazone and 15-deoxy-delta 12,14-prostaglandin J2 on rat cultured cerebellar granule neuronal viability. J Neurosci Res 2003; 72:747-55. [PMID: 12774315 DOI: 10.1002/jnr.10613] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Peroxisome proliferator-activated receptor gamma (PPARgamma) has been the focus of studies assessing its potential neuroprotective role. These studies have shown either neuroprotection or neurotoxicity by PPARgamma ligands. Comparison of these studies is complicated by the use of different PPARgamma ligands, mechanisms of neurotoxicity induction, and neuronal cell type. In this study, we compared the effects of the synthetic PPARgamma ligand ciglitazone with an endogenous PPARgamma ligand, 15-deoxy-delta(12,14)-prostaglandin J(2) (15-deoxy PGJ(2)), on inherent neurotoxicity and neuroprotection using a reduction in extracellular KCl in rat cultured cerebellar granule neurons (CGN). We also assessed the effects of these ligands on c-Jun protein expression, which is up-regulated on induction of low-KCl-mediated neuronal apoptosis as well as being associated with PPAR in other cell types. We showed that PPARgamma mRNA is expressed in CGN cultures and observed ciglitazone- and 15-deoxy PGJ(2)-mediated inherent neurotoxicity that was concentration and time dependent. c-Jun was only modestly increased in the presence of ciglitazone but was markedly up-regulated by 15-deoxy PGJ(2) after 12 hr. Treatment of CGN cultures with ciglitazone simultaneous with KCl withdrawal resulted in a modest, time-dependent neuroprotection. Such neuroprotection after KCl withdrawal was not observed with 15-deoxy PGJ(2). Despite the absence of neuroprotection, 15-deoxy PGJ(2) markedly inhibited the early up-regulation of c-Jun during KCl withdrawal. These studies suggest that ciglitazone and 15-deoxy PGJ(2) have markedly different effects on inherent and low-KCl-induced toxicity and c-Jun expression in CGN, indicating potential non-PPARgamma mechanisms.
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Affiliation(s)
- Steven A Smith
- School of Pharmacy, The University of Queensland, St. Lucia, Queensland, Australia
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Sumanasekera WK, Tien ES, Turpey R, Vanden Heuvel JP, Perdew GH. Evidence that peroxisome proliferator-activated receptor alpha is complexed with the 90-kDa heat shock protein and the hepatitis virus B X-associated protein 2. J Biol Chem 2003; 278:4467-73. [PMID: 12482853 DOI: 10.1074/jbc.m211261200] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The peroxisome proliferator-activated receptor alpha (PPARalpha) is a ligand-inducible transcription factor, which belongs to the nuclear receptor superfamily. PPARalpha mediates the carcinogenic effects of peroxisome proliferators in rodents. In humans, PPARalpha plays a fundamental role in regulating energy homeostasis via control of lipid metabolism. To study the possible role of chaperone proteins in the regulation of PPARalpha activity, a monoclonal antibody (mAb) was made against PPARalpha and designated as 3B6/PPAR. The specificity of mAb 3B6/PPAR in recognizing PPARalpha was tested in immunoprecipitations using in vitro translated PPAR subtypes. The mAb 3B6/PPAR recognized PPARalpha, failed to bind to PPARbeta or PPARgamma, and is efficient in both immunoprecipitating and visualizing the receptor on protein blots. The immunoprecipitation of PPARalpha in mouse liver cytosol using mAb 3B6/PPAR has resulted in the detection of two co-immunoprecipitated proteins, which are heat shock protein 90 (hsp90) and the hepatitis B virus X-associated protein 2 (XAP2). The concomitant depletion of PPARalpha in hsp90-depleted mouse liver cytosol was also detected. Complex formation between XAP2 and PPARalpha/FLAG was also demonstrated in an in vitro translation binding assay. hsp90 interacts with PPARalpha in a mammalian two-hybrid assay and binds to the E/F domain. Transient expression of XAP2 co-expressed with PPARalpha resulted in down-regulation of a peroxisome proliferator response element-driven reporter gene activity. Taken together, these results indicate that PPARalpha is in a complex with hsp90 and XAP2, and XAP2 appears to function as a repressor. This is the first demonstration that PPARalpha is stably associated with other proteins in tissue extracts and the first nuclear receptor shown to functionally interact with XAP2.
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Affiliation(s)
- Wasana K Sumanasekera
- Center for Molecular Toxicology and Carcinogenesis, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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38
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Diep QN, El Mabrouk M, Cohn JS, Endemann D, Amiri F, Virdis A, Neves MF, Schiffrin EL. Structure, endothelial function, cell growth, and inflammation in blood vessels of angiotensin II-infused rats: role of peroxisome proliferator-activated receptor-gamma. Circulation 2002; 105:2296-302. [PMID: 12010913 DOI: 10.1161/01.cir.0000016049.86468.23] [Citation(s) in RCA: 279] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Pioglitazone and rosiglitazone, thiazolidinedione peroxisome proliferator-activated receptor-gamma (PPARgamma) activators, reduce blood pressure (BP) in some hypertensive models by unclear mechanisms. We tested the hypothesis that pioglitazone or rosiglitazone would prevent BP elevation and vascular dysfunction in angiotensin (Ang) II-infused rats by direct vascular effects. METHODS AND RESULTS Sprague-Dawley rats received Ang II (120 ng x kg(-1) x min(-1) SC) with or without pioglitazone (10 mg x kg(-1) x d(-1)) or rosiglitazone (5 mg x kg(-1) x d(-1)) for 7 days. Systolic BP, elevated in Ang II-infused rats (176+/-5 mm Hg) versus controls (109+/-2 mm Hg, P<0.01), was reduced by pioglitazone (134+/-2 mm Hg) or rosiglitazone (123+/-2 mm Hg). In mesenteric small arteries studied in a pressurized myograph, media/lumen ratio was increased (P<0.05) and acetylcholine-induced relaxation impaired in Ang II-infused rats (P<0.05); both were normalized by the thiazolidinediones. In Ang II-infused rats, vascular DNA synthesis (by 3H-thymidine incorporation); expression of cell cycle proteins cyclin D1 and cdk4, angiotensin II type 1 receptors, vascular cell adhesion molecule-1, and platelet and endothelial cell adhesion molecule; and nuclear factor-kappaB activity were increased. These changes were abrogated by pioglitazone or rosiglitazone. CONCLUSIONS Thiazolidinedione PPAR-gamma activators attenuated the development of hypertension, corrected structural abnormalities, normalized cell growth, and improved endothelial dysfunction induced by Ang II and prevented upregulation of angiotensin II type 1 receptors, cell cycle proteins, and proinflammatory mediators. Thiazolidinediones may be useful in the prevention and/or treatment of hypertension, particularly when it is associated with insulin resistance or diabetes mellitus.
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Affiliation(s)
- Quy N Diep
- Canadian Institutes of Health Research Multidisciplinary Research Group on Hypertension, Montreal, Quebec, Canada
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Abstract
An essential process for fatty acid digestion, absorption and assimilation is the constant replacement of mature intestinal epithelial cells by differentiating stem cells. Free fatty acids (FFA) and PYY may act in concert to alter mucosal cell differentiation through the cytoskeletal-extracellular matrix interactions. PYY induced expression of tetraspanins and intestinal fatty acid binding protein (I-FABP) may be part of a mechanism whereby FFA modulate expression of differentiation dependent proteins in the mucosa. This modulation provides a means for FFA to act as signal molecules in the feedback regulation of their own assimilation.
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Affiliation(s)
- Gregory W Aponte
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720-3104, USA.
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40
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Monjazeb AM, Clay CE, High KP, Chilton FH. Antineoplastic properties of arachidonic acid and its metabolites. Prostaglandins Leukot Essent Fatty Acids 2002; 66:5-12. [PMID: 12051952 DOI: 10.1054/plef.2001.0334] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- A M Monjazeb
- Department of Cancer Biology, Wake Forest University Baptist Medical Center, School of Medicine, Winston-Salem, NC, USA
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41
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Smith SA, May FJ, Monteith GR, Roberts-Thomson SJ. Activation of the peroxisome proliferator-activated receptor-alpha enhances cell death in cultured cerebellar granule cells. J Neurosci Res 2001; 66:236-41. [PMID: 11592119 DOI: 10.1002/jnr.1216] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Peroxisome proliferator-activated receptor-alpha (PPARalpha) is a member of the steroid hormone receptor superfamily. In rodents, PPARalpha alters genes involved in cell cycle regulation in hepatocytes. Some of these genes are implicated in neuronal cell death. Therefore, in this study, we examined the toxicological consequence of PPARalpha activation in rat primary cultures of cerebellar granule neurons. Our studies demonstrated the presence of PPARalpha mRNA in cultures by reverse transcriptase-polymerase chain reaction. After 10 days in vitro, cerebellar granule neuron cultures were incubated with the selective PPARalpha activator 4-chloro-6-(2,3-xylidino)2-pyrimidinylthioacetic acid (Wy-14,643). The inherent toxicity of Wy-14,643 and the effect of PPARalpha activation following toxic stimuli were assessed. In these studies, neurotoxicity was induced through reduction of extracellular [KCl] from 25 mM to 5.36 mM. We observed no inherent toxicity of Wy-14,643 (24 hr) in cultured cerebellar granule cells. However, after reduction of [KCl], cerebellar granule cell cultures incubated with Wy-14,643 showed significantly greater toxicity than controls. These results suggest a possible role for PPARalpha in augmentation of cerebellar granule neuronal death after toxic stimuli.
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Affiliation(s)
- S A Smith
- School of Pharmacy, The University of Queensland, St. Lucia, Queensland 4072, Australia
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42
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Nakabayashi H, Koyama Y, Sakai M, Li HM, Wong NC, Nishi S. Glucocorticoid stimulates primate but inhibits rodent alpha-fetoprotein gene promoter. Biochem Biophys Res Commun 2001; 287:160-72. [PMID: 11549270 DOI: 10.1006/bbrc.2001.5564] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucocorticoids inhibit rodent alpha-fetoprotein (AFP) gene activity but stimulate expression of the human homologue. Like human, activity of the AFP promoter from other primates was stimulated by the synthetic glucocorticoid dexamethasone (Dex) in various cell lines. A glucocorticoid responsive element (GRE) is located within 180 bp upstream of the transcription initiation site of all AFP genes examined. Comparative analysis of the GRE in the two different groups of promoters revealed a common 3' hexamer, 5'-TGTCCT-3', but the 5' hexamers were different. This difference converts the rodent GRE to a DR-1 motif. DR-1 is a binding site for members of the nuclear receptor superfamily including the orphan receptor hepatocyte nuclear factor-4 (HNF-4). The presence of DR-1 in the rodent but not human may underlie the opposite actions of Dex on the AFP promoter. We tested this hypothesis using a transient transfection assay. In hepatoma cells that expressed GR and HNF-4, reporter-activity was inhibited by Dex. The same construct in nonhepatoma cells was strongly induced by over expression of HNF-4 and the induced activity was inhibited by Dex. The findings show that Dex induction of human AFP is mediated by a GRE. But Dex repression of the rodent promoter requires a DR-1 motif that interacts with GR and HNF-4.
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Affiliation(s)
- H Nakabayashi
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo 060-8638, Japan.
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43
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Okuno M, Arimoto E, Ikenobu Y, Nishihara T, Imagawa M. Dual DNA-binding specificity of peroxisome-proliferator-activated receptor gamma controlled by heterodimer formation with retinoid X receptor alpha. Biochem J 2001; 353:193-8. [PMID: 11139380 PMCID: PMC1221558 DOI: 10.1042/0264-6021:3530193] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The peroxisome-proliferator-activated receptor gamma (PPARgamma) is a member of the steroid/thyroid nuclear receptor superfamily of ligand-activated transcription factors. PPARgamma forms a heterodimer with the retinoid X receptor alpha (RXRalpha) and binds to a common consensus response element consisting of a direct repeat of two hexanucleotides spaced by one nucleotide (DR1 motif). However, other hexamer configurations for binding of PPARgamma have not been considered. By using PCR-mediated random site selection, the DNA sequence preferences for PPARgamma binding were examined. In this study, we have demonstrated that PPARgamma has dual DNA-binding specificity; binding to both the DR1 motif and a palindromic sequence with three bases as spacers (Pal3 motif). The consensus sequence selected by equimolar amounts of PPARgamma and RXRalpha was a perfect DR1 motif, whereas a relatively large population of Pal3 was observed when a 30-fold molar excess of PPARgamma over RXRalpha was used. Gel-shift analysis revealed that the PPARgamma homodimer could bind to Pal3 and that the affinity constant of the PPARgamma homodimer for Pal3 was nearly the same as that of the PPARgamma/RXRalpha heterodimer for DR1. The addition of RXRalpha decreased the binding affinity of PPARgamma for Pal3, indicating that the DNA-binding specificity of PPARgamma could be altered by heterodimer formation with RXRalpha.
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Affiliation(s)
- M Okuno
- Laboratory of Environmental Biochemistry, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-Oka, Suita, Osaka 565-0871, Japan
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Cancio I, Cajaraville MP. Cell biology of peroxisomes and their characteristics in aquatic organisms. INTERNATIONAL REVIEW OF CYTOLOGY 2000; 199:201-93. [PMID: 10874580 DOI: 10.1016/s0074-7696(00)99005-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
The general characteristics of peroxisomes in different organisms, including aquatic organisms such as fish, crustaceans, and mollusks, are reviewed, with special emphasis on different aspects of the organelle biogenesis and mechanistic aspects of peroxisome proliferation. Peroxisome proliferation and peroxisomal enzyme inductions elicited by xenobiotics or physiological conditions have become useful tools to study the mechanisms of peroxisome biogenesis. During peroxisome proliferation, the induction of peroxisomal proteins is heterogeneous, enzymes that show increased activity being involved in different aspects of lipid homeostasis. The process of peroxisome biogenesis is coordinately triggered by a whole array of structurally dissimilar compounds known as peroxisome proliferators, and investigating the effect of some of these compounds that commonly appear as pollutants in the environment on the peroxisomes of aquatic animals inhabiting marine and estuarine habitats seems interesting. It is also important to determine whether peroxisome proliferation in these animals is a phenomenon that might occur under normal physiological or season-related conditions and plays a metabolic or functional role. This would help set the basis for understanding the process of peroxisome biogenesis in aquatic animals.
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Affiliation(s)
- I Cancio
- Zoologia eta Animali Zelulen Dinamika Saila, Euskal Herriko Unibertsitatea, Bilbo/Basque Country, Spain
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45
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Panet-Raymond V, Gottlieb B, Beitel LK, Pinsky L, Trifiro MA. Interactions between androgen and estrogen receptors and the effects on their transactivational properties. Mol Cell Endocrinol 2000; 167:139-50. [PMID: 11000528 DOI: 10.1016/s0303-7207(00)00279-3] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The physiological interplay of androgen and estrogen action in endocrine tissues is well recognized. The biochemical processes responsible for this interplay have yet to be fully defined. We have demonstrated that the androgen receptor (AR) and estrogen receptor-alpha (ERalpha) can interact directly using the yeast and mammalian two-hybrid systems. These interactions occurred between the C-terminal ERalpha ligand-binding domain and either the N-terminal AR transactivational domain or the full-length AR. Estrogen receptor-beta (ERbeta) did not interact with the AR. DNA cotransfection studies employing AR, ERalpha and ERbeta expression vectors and AR- or ER-reporter gene constructs were used to identify and measure potential functional effects of AR-ER interaction. Coexpression of ERalpha with AR decreased AR transactivation by 35%; coexpression of AR with ERalpha decreased ERalpha transactivation by 74%. Coexpression of AR and ERbeta did not significantly modulate AR or ERbeta transactivation. In summary, we have shown that specific domains of AR and ERalpha physically interact and have demonstrated the functional consequences of such interaction. These results may help explain the nature of the physiological interplay between androgens and estrogens.
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Affiliation(s)
- V Panet-Raymond
- Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital, 3755 Cote-Ste-Catherine Road, Quebec, H3T 1E2, Montreal, Canada
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Roberts-Thomson SJ. Peroxisome proliferator-activated receptors in tumorigenesis: targets of tumour promotion and treatment. Immunol Cell Biol 2000; 78:436-41. [PMID: 10947870 DOI: 10.1046/j.1440-1711.2000.00921.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The peroxisome proliferator-activated receptors (PPAR) are ligand-activated transcription factors. There are three genes that code for the PPAR isoforms: PPARalpha, PPARbeta and PPARgamma. In the present review, studies characterizing the various PPAR isoforms are discussed. Peroxisome proliferator-activated receptor alpha has been implicated in the lipid-lowering effects of the fibrate drugs. Peroxisome proliferator-activated receptor gamma has a clear role in adipocyte differentiation and is therapeutically targeted by the thiazolidinedione drugs for the treatment of type II diabetes. The physiological role of PPARbeta is less well understood but, as described in the present review, recent studies have implicated it with a role in colon cancer. In the present review, particular attention is focused on the role of PPAR in the regulation of expression of proteins associated with cell cycle control and tumorigenesis.
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47
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Sohlenius-Sternbeck AK, Appelkvist EL, DePierre JW. Effects of vitamin A deficiency on selected xenobiotic-metabolizing enzymes and defenses against oxidative stress in mouse liver. Biochem Pharmacol 2000; 59:377-83. [PMID: 10644045 DOI: 10.1016/s0006-2952(99)00337-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Male and female C57B1/6 mice were rendered vitamin A-deficient, and the effects of this deficiency on certain xenobiotic-metabolizing enzymes and defenses against oxidative stress were examined. Vitamin A deficiency significantly increased the levels of DT-diaphorase, glutathione transferase, and catalase in the hepatic cytosolic fraction from male mice (5.2-, 1.6-, and 3.5-fold, respectively), as well as from female mice (4.8-, 3.3-, and 2.4-fold, respectively). In the hepatic mitochondrial fraction (containing peroxisomes) from male animals, the activities of urate oxidase and catalase were increased 3.4- and 1.7-fold, respectively. The activity of catalase in the mitochondrial fraction from female mice was not affected by vitamin A deficiency, whereas the activity of peroxisomal urate oxidase was increased 2.9-fold. The hepatic level of ubiquinone was increased somewhat. The significance of the increases observed here is presently unclear, but it may be speculated that vitamin A and/or its metabolites are somehow involved in the down-regulation of these proteins. Another possibility is that these enzymes are increased as a result of hepatic oxidative stress caused by vitamin A deficiency. However, vitamin A deficiency had no effect on the activity of superoxide dismutase in this study, whereas the activity of glutathione peroxidase was slightly decreased (27%) in the hepatic cytosolic fraction from male mice. In addition, the hepatic level of alpha-tocopherol was decreased dramatically in the vitamin A-deficient animals.
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48
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McCarty MF. Peroxisome proliferators as adjuvants for the reverse-electron-transport therapy of obesity: an explanation for the large increase in metabolic rate of MEDICA 16-treated rats. Med Hypotheses 1999; 53:272-6. [PMID: 10608261 DOI: 10.1054/mehy.1998.0757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The efficacy of reverse-electron-transport therapy of obesity should be promoted by agents which up-regulate hepatocyte enzymes that are potentially rate-limiting for mitochondrial fatty acid oxidation and electron shuttles. Peroxisome proliferator drugs, including the fibrates used to treat hyperlipidemia, may be useful in this regard, as they induce malic enzyme, the mitochondrial glycerol-3-phosphate dehydrogenase, and carnitine palmitoyl transferase I in rodent hepatocytes. An agent of this class, MEDICA 16, has the additional property of potently inhibiting both citrate lyase and acetyl-CoA carboxylase. As a result, methyl-substituted diacarboxylic acids (MEDICA) 16 can be expected to disinhibit hepatic fatty acid oxidation while up-regulating electron shuttle mechanisms, and thus should stimulate reverse electron transport. This may explain the remarkable 40% increase in basal metabolic rate observed in normal rats ingesting MEDICA 16--an effect not associated with any compensatory increase in food intake. Relative to controls, the MEDICA 16-treated rats achieved a 50% reduction in body fat and a modest increase in lean mass, such that weight and growth were not changed. In other rodent strains, MEDICA 16 has prevented obesity diabetes and atherogenesis. However, whether MEDICA 16 and other peroxisome proliferator drugs will have clinical utility in reverse-electron-transport therapy may hinge on their ability to induce key enzymes in human hepatocytes; cell culture studies to evaluate this are required.
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Dowell P, Ishmael JE, Avram D, Peterson VJ, Nevrivy DJ, Leid M. Identification of nuclear receptor corepressor as a peroxisome proliferator-activated receptor alpha interacting protein. J Biol Chem 1999; 274:15901-7. [PMID: 10336495 DOI: 10.1074/jbc.274.22.15901] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nuclear receptor corepressor (NCoR) was demonstrated to interact strongly with peroxisome proliferator-activated receptor alpha (PPARalpha), and PPARalpha ligands suppressed this interaction. In contrast to the interaction of PPARalpha with the coactivator protein, p300, association of the receptor with NCoR did not require any part of the PPARalpha ligand binding domain. NCoR was found to suppress PPARalpha-dependent transcriptional activation in the context of a PPARalpha.retinoid X receptor alpha (RXRalpha) heterodimeric complex bound to a peroxisome proliferator-responsive element in human embryonic kidney 293 cells. This repression was reversed agonists of either receptor demonstrating a functional interaction between NCoR and PPARalpha.RXRalpha heterodimeric complexes in mammalian cells. NCoR appears to influence PPARalpha signaling pathways and, therefore, may modulate tissue responsiveness to peroxisome proliferators.
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Affiliation(s)
- P Dowell
- Program in Molecular and Cellular Biology, College of Pharmacy, Oregon State University, Corvallis, Oregon 97331, USA
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50
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Canan Koch SS, Dardashti LJ, Cesario RM, Croston GE, Boehm MF, Heyman RA, Nadzan AM. Synthesis of retinoid X receptor-specific ligands that are potent inducers of adipogenesis in 3T3-L1 cells. J Med Chem 1999; 42:742-50. [PMID: 10052980 DOI: 10.1021/jm980621r] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel series of oxime ligands has been synthesized that displays potent, specific activation of the retinoid X receptors (RXRs). The oximes of 3-substituted (tetramethyltetrahydronaphthyl)carbonylbenzoic acids are readily available by condensation with hydroxyl- or methoxylamine; alkylation of the hydroxyl oxime provides a variety of analogues. Oximes and variously substituted oxime derivatives demonstrate high binding affinity for the RXRs and specific RXR activation and, hence, are called rexinoids. These oxime rexinoids are activators of the RXR:PPARgamma heterodimer and are potent inducers of differentiation of 3T3-L1 preadipocytes to adipocytes. We have recently reported that ligands which activate the RXR:PPARgamma heterodimer in this manner are effective in the treatment of type II diabetes (non-insulin-dependent diabetes mellitus, NIDDM). Thus, these new oxime rexinoids are potential therapeutic agents for the treatment of metabolic disorders, such as obesity and diabetes.
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Affiliation(s)
- S S Canan Koch
- Departments of Medicinal Chemistry, Retinoid Research, and New Leads Discovery, Ligand Pharmaceuticals, Incorporated, 10255 Science Center Drive, San Diego, California 92121, USA
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