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Ballav S, Bhosale M, Lokhande KB, Paul MK, Padhye S, Swamy KV, Ranjan A, Basu S. Design, Synthesis, and Biological Evaluation of Novel Quercetin Derivatives as PPAR-γ Partial Agonists by Modulating Epithelial-Mesenchymal Transition in Lung Cancer Metastasis. Adv Biol (Weinh) 2023; 7:e2300036. [PMID: 37017501 DOI: 10.1002/adbi.202300036] [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: 01/23/2023] [Revised: 03/09/2023] [Indexed: 04/06/2023]
Abstract
Epithelial-to-mesenchymal transition (EMT) is responsible for driving metastasis of multiple cancer types including lung cancer. Peroxisome proliferator-activated receptor (PPAR)-γ, a ligand-activated transcription factor, controls expression of variety of genes involved in EMT. Although several synthetic compounds act as potent full agonists for PPAR-γ, their long term application is restricted due to serious adverse effects. Therefore, partial agonists involving reduced and balanced PPAR-γ activity are more effective and valued. A previous study discerned the efficacy of quercetin and its derivatives to attain favorable stabilization with PPAR-γ. Here this work is extended by synthesizing five novel quercetin derivatives (QDs) namely thiosemicarbazone (QUETSC)) and hydrazones (quercetin isonicotinic acid hydrazone (QUEINH), quercetin nicotinic acid hydrazone (QUENH), quercetin 2-furoic hydrazone (QUE2FH), and quercetin salicyl hydrazone (QUESH)) and their effects are analyzed in modulating EMT in lung cancer cell lines via PPAR-γ partial activation. QDs-treated A549 cells diminish cell proliferation strongly at nanomolar concentration compared to NCI-H460 cells. Of the five screened derivatives, QUETSC, QUE2FH, and QUESH exhibit the property of partial activation as compared to the overexpressive level of rosiglitazone. Consistently, these QDs also suppress EMT process by markedly downregulating the levels of mesenchymal markers (Snail, Slug, and zinc finger E-box binding homeobox 1) and concomitant upregulation of epithelial marker (E-cadherin).
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Affiliation(s)
- Sangeeta Ballav
- Cancer and Translational Research Centre, Dr. D.Y. Patil Biotechnology and Bioinformatics Institute, Dr. D.Y. Patil Vidyapeeth, Tathawade, Pune, Maharashtra, 411 033, India
| | - Mrinalini Bhosale
- Department of Chemistry, Interdisciplinary Science and Technology Research Academy, Abeda Inamdar Senior College, University of Pune, Maharashtra, 411001, India
| | - Kiran Bharat Lokhande
- Bioinformatics Research Laboratory, Dr. D.Y. Patil Biotechnology and Bioinformatics Institute, Dr. D.Y. Patil Vidyapeeth, Tathawade, Pune, Maharashtra, 411 033, India
| | - Manash K Paul
- Department of Pulmonary and Critical Care Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Subhash Padhye
- Department of Chemistry, Interdisciplinary Science and Technology Research Academy, Abeda Inamdar Senior College, University of Pune, Maharashtra, 411001, India
| | - K Venkateswara Swamy
- Bioinformatics Research Laboratory, Dr. D.Y. Patil Biotechnology and Bioinformatics Institute, Dr. D.Y. Patil Vidyapeeth, Tathawade, Pune, Maharashtra, 411 033, India
- MIT School of Bioengineering Science and Research, MIT - Art, Design and Technology University, Pune, Maharashtra, 412201, India
| | - Amit Ranjan
- Cancer and Translational Research Centre, Dr. D.Y. Patil Biotechnology and Bioinformatics Institute, Dr. D.Y. Patil Vidyapeeth, Tathawade, Pune, Maharashtra, 411 033, India
| | - Soumya Basu
- Cancer and Translational Research Centre, Dr. D.Y. Patil Biotechnology and Bioinformatics Institute, Dr. D.Y. Patil Vidyapeeth, Tathawade, Pune, Maharashtra, 411 033, India
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Bravo-Ruiz I, Medina MÁ, Martínez-Poveda B. From Food to Genes: Transcriptional Regulation of Metabolism by Lipids and Carbohydrates. Nutrients 2021; 13:nu13051513. [PMID: 33946267 PMCID: PMC8145205 DOI: 10.3390/nu13051513] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 04/28/2021] [Indexed: 12/31/2022] Open
Abstract
Lipids and carbohydrates regulate gene expression by means of molecules that sense these macronutrients and act as transcription factors. The peroxisome proliferator-activated receptor (PPAR), activated by some fatty acids or their derivatives, and the carbohydrate response element binding protein (ChREBP), activated by glucose-derived metabolites, play a key role in metabolic homeostasis, especially in glucose and lipid metabolism. Furthermore, the action of both factors in obesity, diabetes and fatty liver, as well as the pharmacological development in the treatment of these pathologies are indeed of high relevance. In this review we present an overview of the discovery, mechanism of activation and metabolic functions of these nutrient-dependent transcription factors in different tissues contexts, from the nutritional genomics perspective. The possibility of targeting these factors in pharmacological approaches is also discussed. Lipid and carbohydrate-dependent transcription factors are key players in the complex metabolic homeostasis, but these factors also drive an adaptive response to non-physiological situations, such as overeating. Possibly the decisive role of ChREBP and PPAR in metabolic regulation points to them as ideal therapeutic targets, but their pleiotropic functions in different tissues makes it difficult to "hit the mark".
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Affiliation(s)
- Inés Bravo-Ruiz
- Andalucía Tech, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, E-29071 Málaga, Spain; (I.B.-R.); (M.Á.M.)
| | - Miguel Ángel Medina
- Andalucía Tech, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, E-29071 Málaga, Spain; (I.B.-R.); (M.Á.M.)
- Instituto de Investigación Biomédica de Málaga (IBIMA), E-29071 Málaga, Spain
- CIBER de Enfermedades Raras (CIBERER), E-29071 Málaga, Spain
| | - Beatriz Martínez-Poveda
- Andalucía Tech, Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, E-29071 Málaga, Spain; (I.B.-R.); (M.Á.M.)
- Instituto de Investigación Biomédica de Málaga (IBIMA), E-29071 Málaga, Spain
- CIBER de Enfermedades Cardiovasculares (CIBERCV), E-28029 Madrid, Spain
- Correspondence:
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Dixon ED, Nardo AD, Claudel T, Trauner M. The Role of Lipid Sensing Nuclear Receptors (PPARs and LXR) and Metabolic Lipases in Obesity, Diabetes and NAFLD. Genes (Basel) 2021; 12:genes12050645. [PMID: 33926085 PMCID: PMC8145571 DOI: 10.3390/genes12050645] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 12/11/2022] Open
Abstract
Obesity and type 2 diabetes mellitus (T2DM) are metabolic disorders characterized by metabolic inflexibility with multiple pathological organ manifestations, including non-alcoholic fatty liver disease (NAFLD). Nuclear receptors are ligand-dependent transcription factors with a multifaceted role in controlling many metabolic activities, such as regulation of genes involved in lipid and glucose metabolism and modulation of inflammatory genes. The activity of nuclear receptors is key in maintaining metabolic flexibility. Their activity depends on the availability of endogenous ligands, like fatty acids or oxysterols, and their derivatives produced by the catabolic action of metabolic lipases, most of which are under the control of nuclear receptors. For example, adipose triglyceride lipase (ATGL) is activated by peroxisome proliferator-activated receptor γ (PPARγ) and conversely releases fatty acids as ligands for PPARα, therefore, demonstrating the interdependency of nuclear receptors and lipases. The diverse biological functions and importance of nuclear receptors in metabolic syndrome and NAFLD has led to substantial effort to target them therapeutically. This review summarizes recent findings on the roles of lipases and selected nuclear receptors, PPARs, and liver X receptor (LXR) in obesity, diabetes, and NAFLD.
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Affiliation(s)
| | | | | | - Michael Trauner
- Correspondence: ; Tel.: +43-140-4004-7410; Fax: +43-14-0400-4735
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4
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Christofides A, Konstantinidou E, Jani C, Boussiotis VA. The role of peroxisome proliferator-activated receptors (PPAR) in immune responses. Metabolism 2021; 114:154338. [PMID: 32791172 PMCID: PMC7736084 DOI: 10.1016/j.metabol.2020.154338] [Citation(s) in RCA: 226] [Impact Index Per Article: 75.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/06/2020] [Accepted: 07/24/2020] [Indexed: 02/07/2023]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are fatty acid-activated transcription factors of nuclear hormone receptor superfamily that regulate energy metabolism. Currently, three PPAR subtypes have been identified: PPARα, PPARγ, and PPARβ/δ. PPARα and PPARδ are highly expressed in oxidative tissues and regulate genes involved in substrate delivery and oxidative phosphorylation (OXPHOS) and regulation of energy homeostasis. In contrast, PPARγ is more important in lipogenesis and lipid synthesis, with highest expression levels in white adipose tissue (WAT). In addition to tissues regulating whole body energy homeostasis, PPARs are expressed in immune cells and have an emerging critical role in immune cell differentiation and fate commitment. In this review, we discuss the actions of PPARs in the function of the innate and the adaptive immune system and their implications in immune-mediated inflammatory conditions.
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Affiliation(s)
- Anthos Christofides
- Division of Hematology-Oncology, Harvard Medical School, Boston, MA 02215, United States of America; Department of Medicine, Harvard Medical School, Boston, MA 02215, United States of America; Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, United States of America
| | - Eirini Konstantinidou
- Division of Hematology-Oncology, Harvard Medical School, Boston, MA 02215, United States of America; Department of Medicine, Harvard Medical School, Boston, MA 02215, United States of America; Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, United States of America
| | - Chinmay Jani
- Department of Medicine, Harvard Medical School, Boston, MA 02215, United States of America; Department of Medicine, Mt. Auburn Hospital, Cambridge, MA 02138, United States of America
| | - Vassiliki A Boussiotis
- Division of Hematology-Oncology, Harvard Medical School, Boston, MA 02215, United States of America; Department of Medicine, Harvard Medical School, Boston, MA 02215, United States of America; Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, United States of America.
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Hernandez-Quiles M, Broekema MF, Kalkhoven E. PPARgamma in Metabolism, Immunity, and Cancer: Unified and Diverse Mechanisms of Action. Front Endocrinol (Lausanne) 2021; 12:624112. [PMID: 33716977 PMCID: PMC7953066 DOI: 10.3389/fendo.2021.624112] [Citation(s) in RCA: 158] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/08/2021] [Indexed: 12/20/2022] Open
Abstract
The proliferator-activated receptor γ (PPARγ), a member of the nuclear receptor superfamily, is one of the most extensively studied ligand-inducible transcription factors. Since its identification in the early 1990s, PPARγ is best known for its critical role in adipocyte differentiation, maintenance, and function. Emerging evidence indicates that PPARγ is also important for the maturation and function of various immune system-related cell types, such as monocytes/macrophages, dendritic cells, and lymphocytes. Furthermore, PPARγ controls cell proliferation in various other tissues and organs, including colon, breast, prostate, and bladder, and dysregulation of PPARγ signaling is linked to tumor development in these organs. Recent studies have shed new light on PPARγ (dys)function in these three biological settings, showing unified and diverse mechanisms of action. Classical transactivation-where PPARγ activates genes upon binding to PPAR response elements as a heterodimer with RXRα-is important in all three settings, as underscored by natural loss-of-function mutations in FPLD3 and loss- and gain-of-function mutations in tumors. Transrepression-where PPARγ alters gene expression independent of DNA binding-is particularly relevant in immune cells. Interestingly, gene translocations resulting in fusion of PPARγ with other gene products, which are unique to specific carcinomas, present a third mode of action, as they potentially alter PPARγ's target gene profile. Improved understanding of the molecular mechanism underlying PPARγ activity in the complex regulatory networks in metabolism, cancer, and inflammation may help to define novel potential therapeutic strategies for prevention and treatment of obesity, diabetes, or cancer.
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Affiliation(s)
- Miguel Hernandez-Quiles
- Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Marjoleine F. Broekema
- Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Eric Kalkhoven
- Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
- *Correspondence: Eric Kalkhoven,
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Traynor S, Møllegaard NE, Jørgensen MG, Brückmann NH, Pedersen CB, Terp MG, Johansen S, Dejardin J, Ditzel HJ, Gjerstorff MF. Remodeling and destabilization of chromosome 1 pericentromeric heterochromatin by SSX proteins. Nucleic Acids Res 2020; 47:6668-6684. [PMID: 31114908 PMCID: PMC6648343 DOI: 10.1093/nar/gkz396] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 04/30/2019] [Accepted: 05/01/2019] [Indexed: 12/31/2022] Open
Abstract
Rearrangement of the 1q12 pericentromeric heterochromatin and subsequent amplification of the 1q arm is commonly associated with cancer development and progression and may result from epigenetic deregulation. In many premalignant and malignant cells, loss of 1q12 satellite DNA methylation causes the deposition of polycomb factors and formation of large polycomb aggregates referred to as polycomb bodies. Here, we show that SSX proteins can destabilize 1q12 pericentromeric heterochromatin in melanoma cells when it is present in the context of polycomb bodies. We found that SSX proteins deplete polycomb bodies and promote the unfolding and derepression of 1q12 heterochromatin during replication. This further leads to segregation abnormalities during anaphase and generation of micronuclei. The structural rearrangement of 1q12 pericentromeric heterochromatin triggered by SSX2 is associated with loss of polycomb factors, but is not mediated by diminished polycomb repression. Instead, our studies suggest a direct effect of SSX proteins facilitated though a DNA/chromatin binding, zinc finger-like domain and a KRAB-like domain that may recruit chromatin modifiers or activate satellite transcription. Our results demonstrate a novel mechanism for generation of 1q12-associated genomic instability in cancer cells.
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Affiliation(s)
- Sofie Traynor
- Department of Cancer and Inflammation Research, Institute for Molecular Medicine, University of Southern Denmark, J.B. Winsløws Vej 25, DK-5000 Odense, Denmark
| | - Niels Erik Møllegaard
- Department of Cellular and Molecular Medicine, University of Copenhagen DK-2200, Denmark
| | - Mikkel G Jørgensen
- Department of Biochemistry and Molecular Biology, Institute for Natural Sciences, University of Southern Denmark, Campusvej 55, DK-5000 Odense, Denmark
| | - Nadine H Brückmann
- Department of Cancer and Inflammation Research, Institute for Molecular Medicine, University of Southern Denmark, J.B. Winsløws Vej 25, DK-5000 Odense, Denmark
| | - Christina B Pedersen
- Department of Cancer and Inflammation Research, Institute for Molecular Medicine, University of Southern Denmark, J.B. Winsløws Vej 25, DK-5000 Odense, Denmark
| | - Mikkel G Terp
- Department of Cancer and Inflammation Research, Institute for Molecular Medicine, University of Southern Denmark, J.B. Winsløws Vej 25, DK-5000 Odense, Denmark
| | - Simone Johansen
- Department of Cancer and Inflammation Research, Institute for Molecular Medicine, University of Southern Denmark, J.B. Winsløws Vej 25, DK-5000 Odense, Denmark
| | - Jerome Dejardin
- Institute of Human Genetics CNRS-Université de Montpellier UMR 9002.141 rue de la Cardonille, 34000 Montpellier, France
| | - Henrik J Ditzel
- Department of Cancer and Inflammation Research, Institute for Molecular Medicine, University of Southern Denmark, J.B. Winsløws Vej 25, DK-5000 Odense, Denmark.,Department of Oncology, Odense University Hospital, Sdr. Boulevard 29, DK-5000 Odense, Denmark.,Academy of Geriatric Cancer Research (AgeCare), Odense University Hospital, Sdr. Boulevard 29, DK-5000, Denmark
| | - Morten F Gjerstorff
- Department of Cancer and Inflammation Research, Institute for Molecular Medicine, University of Southern Denmark, J.B. Winsløws Vej 25, DK-5000 Odense, Denmark.,Department of Oncology, Odense University Hospital, Sdr. Boulevard 29, DK-5000 Odense, Denmark.,Academy of Geriatric Cancer Research (AgeCare), Odense University Hospital, Sdr. Boulevard 29, DK-5000, Denmark
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7
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Schubert M, Becher S, Wallert M, Maeß MB, Abhari M, Rennert K, Mosig AS, Große S, Heller R, Grün M, Lorkowski S. The Peroxisome Proliferator-Activated Receptor (PPAR)- γ Antagonist 2-Chloro-5-Nitro-N-Phenylbenzamide (GW9662) Triggers Perilipin 2 Expression via PPAR δ and Induces Lipogenesis and Triglyceride Accumulation in Human THP-1 Macrophages. Mol Pharmacol 2019; 97:212-225. [PMID: 31871304 DOI: 10.1124/mol.119.117887] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 12/06/2019] [Indexed: 12/20/2022] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor family, playing pivotal roles in regulating glucose and lipid metabolism as well as inflammation. While characterizing potential PPARγ ligand activity of natural compounds in macrophages, we investigated their influence on the expression of adipophilin [perilipin 2 (PLIN2)], a well-known PPARγ target. To confirm that a compound regulates PLIN2 expression via PPARγ, we performed experiments using the widely used PPARγ antagonist 2-chloro-5-nitro-N-phenylbenzamide (GW9662). Surprisingly, instead of blocking upregulation of PLIN2 expression in THP-1 macrophages, expression was concentration-dependently induced by GW9662 at concentrations and under conditions commonly used. We found that this unexpected upregulation occurs in many human and murine macrophage cell models and also primary cells. Profiling expression of PPAR target genes showed upregulation of several genes involved in lipid uptake, transport, and storage as well as fatty acid synthesis by GW9662. In line with this and with upregulation of PLIN2 protein, GW9662 elevated lipogenesis and increased triglyceride levels. Finally, we identified PPARδ as a mediator of the substantial unexpected effects of GW9662. Our findings show that: 1) the PPARγ antagonist GW9662 unexpectedly activates PPARδ-mediated signaling in macrophages, 2) GW9662 significantly affects lipid metabolism in macrophages, 3) careful validation of experimental conditions and results is required for experiments involving GW9662, and 4) published studies in a context comparable to this work may have reported erroneous results if PPARγ independence was demonstrated using GW9662 only. In light of our findings, certain existing studies might require reinterpretation regarding the role of PPARγ SIGNIFICANCE STATEMENT: Peroxisome proliferator-activated receptors (PPARs) are targets for the treatment of various diseases, as they are key regulators of inflammation as well as lipid and glucose metabolism. Hence, reliable tools to characterize the molecular effects of PPARs are indispensable. We describe profound and unexpected off-target effects of the PPARγ antagonist 2-chloro-5-nitro-N-phenylbenzamide (GW9662) involving PPARδ and in turn affecting macrophage lipid metabolism. Our results question certain existing studies using GW9662 and make better experimental design of future studies necessary.
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Affiliation(s)
- Martin Schubert
- Institute of Nutrition, Friedrich Schiller University Jena, Jena, Germany (M.S., S.B., M.W., M.B.M., M.A., M.G., S.L.); Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Germany (M.S., M.W., M.G., S.L.); Institute of Biochemistry II, Jena University Hospital, Jena, Germany (K.R., A.S.M.); and Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), Jena University Hospital and Friedrich Schiller University Jena, Jena, Germany (S.G., R.H.)
| | - Stefanie Becher
- Institute of Nutrition, Friedrich Schiller University Jena, Jena, Germany (M.S., S.B., M.W., M.B.M., M.A., M.G., S.L.); Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Germany (M.S., M.W., M.G., S.L.); Institute of Biochemistry II, Jena University Hospital, Jena, Germany (K.R., A.S.M.); and Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), Jena University Hospital and Friedrich Schiller University Jena, Jena, Germany (S.G., R.H.)
| | - Maria Wallert
- Institute of Nutrition, Friedrich Schiller University Jena, Jena, Germany (M.S., S.B., M.W., M.B.M., M.A., M.G., S.L.); Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Germany (M.S., M.W., M.G., S.L.); Institute of Biochemistry II, Jena University Hospital, Jena, Germany (K.R., A.S.M.); and Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), Jena University Hospital and Friedrich Schiller University Jena, Jena, Germany (S.G., R.H.)
| | - Marten B Maeß
- Institute of Nutrition, Friedrich Schiller University Jena, Jena, Germany (M.S., S.B., M.W., M.B.M., M.A., M.G., S.L.); Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Germany (M.S., M.W., M.G., S.L.); Institute of Biochemistry II, Jena University Hospital, Jena, Germany (K.R., A.S.M.); and Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), Jena University Hospital and Friedrich Schiller University Jena, Jena, Germany (S.G., R.H.)
| | - Masoumeh Abhari
- Institute of Nutrition, Friedrich Schiller University Jena, Jena, Germany (M.S., S.B., M.W., M.B.M., M.A., M.G., S.L.); Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Germany (M.S., M.W., M.G., S.L.); Institute of Biochemistry II, Jena University Hospital, Jena, Germany (K.R., A.S.M.); and Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), Jena University Hospital and Friedrich Schiller University Jena, Jena, Germany (S.G., R.H.)
| | - Knut Rennert
- Institute of Nutrition, Friedrich Schiller University Jena, Jena, Germany (M.S., S.B., M.W., M.B.M., M.A., M.G., S.L.); Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Germany (M.S., M.W., M.G., S.L.); Institute of Biochemistry II, Jena University Hospital, Jena, Germany (K.R., A.S.M.); and Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), Jena University Hospital and Friedrich Schiller University Jena, Jena, Germany (S.G., R.H.)
| | - Alexander S Mosig
- Institute of Nutrition, Friedrich Schiller University Jena, Jena, Germany (M.S., S.B., M.W., M.B.M., M.A., M.G., S.L.); Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Germany (M.S., M.W., M.G., S.L.); Institute of Biochemistry II, Jena University Hospital, Jena, Germany (K.R., A.S.M.); and Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), Jena University Hospital and Friedrich Schiller University Jena, Jena, Germany (S.G., R.H.)
| | - Silke Große
- Institute of Nutrition, Friedrich Schiller University Jena, Jena, Germany (M.S., S.B., M.W., M.B.M., M.A., M.G., S.L.); Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Germany (M.S., M.W., M.G., S.L.); Institute of Biochemistry II, Jena University Hospital, Jena, Germany (K.R., A.S.M.); and Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), Jena University Hospital and Friedrich Schiller University Jena, Jena, Germany (S.G., R.H.)
| | - Regine Heller
- Institute of Nutrition, Friedrich Schiller University Jena, Jena, Germany (M.S., S.B., M.W., M.B.M., M.A., M.G., S.L.); Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Germany (M.S., M.W., M.G., S.L.); Institute of Biochemistry II, Jena University Hospital, Jena, Germany (K.R., A.S.M.); and Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), Jena University Hospital and Friedrich Schiller University Jena, Jena, Germany (S.G., R.H.)
| | - Michael Grün
- Institute of Nutrition, Friedrich Schiller University Jena, Jena, Germany (M.S., S.B., M.W., M.B.M., M.A., M.G., S.L.); Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Germany (M.S., M.W., M.G., S.L.); Institute of Biochemistry II, Jena University Hospital, Jena, Germany (K.R., A.S.M.); and Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), Jena University Hospital and Friedrich Schiller University Jena, Jena, Germany (S.G., R.H.)
| | - Stefan Lorkowski
- Institute of Nutrition, Friedrich Schiller University Jena, Jena, Germany (M.S., S.B., M.W., M.B.M., M.A., M.G., S.L.); Competence Cluster for Nutrition and Cardiovascular Health (nutriCARD), Halle-Jena-Leipzig, Germany (M.S., M.W., M.G., S.L.); Institute of Biochemistry II, Jena University Hospital, Jena, Germany (K.R., A.S.M.); and Institute of Molecular Cell Biology, Center for Molecular Biomedicine (CMB), Jena University Hospital and Friedrich Schiller University Jena, Jena, Germany (S.G., R.H.)
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Broekema M, Savage D, Monajemi H, Kalkhoven E. Gene-gene and gene-environment interactions in lipodystrophy: Lessons learned from natural PPARγ mutants. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:715-732. [DOI: 10.1016/j.bbalip.2019.02.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 01/13/2019] [Accepted: 02/02/2019] [Indexed: 12/13/2022]
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9
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Kang ES, Hwang JS, Lee WJ, Lee GH, Choi MJ, Paek KS, Lim DS, Seo HG. Ligand-activated PPARδ inhibits angiotensin II-stimulated hypertrophy of vascular smooth muscle cells by targeting ROS. PLoS One 2019; 14:e0210482. [PMID: 30620754 PMCID: PMC6324793 DOI: 10.1371/journal.pone.0210482] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 12/25/2018] [Indexed: 11/19/2022] Open
Abstract
We investigated the effect of peroxisome proliferator-activated receptor δ (PPARδ) on angiotensin II (Ang II)-triggered hypertrophy of vascular smooth muscle cells (VSMCs). Activation of PPARδ by GW501516, a specific ligand of PPARδ, significantly inhibited Ang II-stimulated protein synthesis in a concentration-dependent manner, as determined by [3H]-leucine incorporation. GW501516-activated PPARδ also suppressed Ang II-induced generation of reactive oxygen species (ROS) in VSMCs. Transfection of small interfering RNA (siRNA) against PPARδ significantly reversed the effects of GW501516 on [3H]-leucine incorporation and ROS generation, indicating that PPARδ is involved in these effects. By contrast, these GW501516-mediated actions were potentiated in VSMCs transfected with siRNA against NADPH oxidase (NOX) 1 or 4, suggesting that ligand-activated PPARδ elicits these effects by modulating NOX-mediated ROS generation. The phosphatidylinositol 3-kinase inhibitor LY294002 also inhibited Ang II-stimulated [3H]-leucine incorporation and ROS generation by preventing membrane translocation of Rac1. These observations suggest that PPARδ is an endogenous modulator of Ang II-triggered hypertrophy of VSMCs, and is thus a potential target to treat vascular diseases associated with hypertrophic changes of VSMCs.
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Affiliation(s)
- Eun Sil Kang
- College of Sang-Huh Life Sciences, Konkuk University, Gwangjin-gu, Seoul, Korea
| | - Jung Seok Hwang
- College of Sang-Huh Life Sciences, Konkuk University, Gwangjin-gu, Seoul, Korea
| | - Won Jin Lee
- College of Sang-Huh Life Sciences, Konkuk University, Gwangjin-gu, Seoul, Korea
| | - Gyeong Hee Lee
- College of Sang-Huh Life Sciences, Konkuk University, Gwangjin-gu, Seoul, Korea
| | - Mi-Jung Choi
- College of Sang-Huh Life Sciences, Konkuk University, Gwangjin-gu, Seoul, Korea
| | | | - Dae-Seog Lim
- Department of Biotechnology, CHA University, Bundang-gu, Seongnam, Korea
| | - Han Geuk Seo
- College of Sang-Huh Life Sciences, Konkuk University, Gwangjin-gu, Seoul, Korea
- * E-mail:
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10
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Sugihara T, Tanaka S, Braga-Tanaka I, Murano H, Nakamura-Murano M, Komura JI. Screening of biomarkers for liver adenoma in low-dose-rate γ-ray-irradiated mice. Int J Radiat Biol 2018; 94:315-326. [PMID: 29424599 DOI: 10.1080/09553002.2018.1439193] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE Chronic low-dose-rate (20 mGy/day) γ-irradiation increases the incidence of hepatocellular adenomas (HCA) in female B6C3F1 mice. The purpose of this study is to identify potential serum biomarkers for these HCAs by a new approach. MATERIAL AND METHODS Microarray analysis were performed to compare the gene expression profiles of HCAs from mice exposed to low-dose-rate γ-rays with those of normal livers from non-irradiated mice. From the differentially expressed genes, those for possibly secretory proteins were selected. Then, the levels of the proteins in sera were analysed by ELISA. RESULTS Microarray analysis identified 4181 genes differentially expressed in HCAs (>2.0-fold). From these genes, those for α-fetoprotein (Afp), α-1B-glycoprotein (A1bg) and serine peptidase inhibitor Kazal type-3 (Spink3) were selected as the genes for candidate proteins. ELISA revealed that the levels of Afp and A1bg proteins in sera significantly increased and decreased, respectively, in low-dose-rate irradiated mice with HCAs and also same tendency was observed in human patients with hepatocellular carcinomas. CONCLUSION These results indicate that A1bg could be a new serum biomarker for liver tumor. This new approach of using microarray to select genes for secretory proteins is useful for prediction of novel tumor markers in sera.
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Affiliation(s)
- Takashi Sugihara
- a Department of Radiobiology , Institute for Environmental Sciences , Rokkasho Kamikita , Aomori , Japan
| | - Satoshi Tanaka
- a Department of Radiobiology , Institute for Environmental Sciences , Rokkasho Kamikita , Aomori , Japan
| | - Ignacia Braga-Tanaka
- a Department of Radiobiology , Institute for Environmental Sciences , Rokkasho Kamikita , Aomori , Japan
| | - Hayato Murano
- b Tohoku Environmental Sciences Services Corporation , Rokkasho Kamikita , Aomori , Japan
| | - Masako Nakamura-Murano
- b Tohoku Environmental Sciences Services Corporation , Rokkasho Kamikita , Aomori , Japan
| | - Jun-Ichiro Komura
- a Department of Radiobiology , Institute for Environmental Sciences , Rokkasho Kamikita , Aomori , Japan
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11
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Brier ASB, Loft A, Madsen J, Rosengren T, Nielsen R, Schmidt SF, Liu Z, Yan Q, Gronemeyer H, Mandrup S. The KDM5 family is required for activation of pro-proliferative cell cycle genes during adipocyte differentiation. Nucleic Acids Res 2017; 45:1743-1759. [PMID: 27899593 PMCID: PMC5389521 DOI: 10.1093/nar/gkw1156] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 11/01/2016] [Accepted: 11/05/2016] [Indexed: 12/23/2022] Open
Abstract
The KDM5 family of histone demethylases removes the H3K4 tri-methylation (H3K4me3) mark frequently found at promoter regions of actively transcribed genes and is therefore generally considered to contribute to corepression. In this study, we show that knockdown (KD) of all expressed members of the KDM5 family in white and brown preadipocytes leads to deregulated gene expression and blocks differentiation to mature adipocytes. KDM5 KD leads to a considerable increase in H3K4me3 at promoter regions; however, these changes in H3K4me3 have a limited effect on gene expression per se. By contrast, genome-wide analyses demonstrate that KDM5A is strongly enriched at KDM5-activated promoters, which generally have high levels of H3K4me3 and are associated with highly expressed genes. We show that KDM5-activated genes include a large set of cell cycle regulators and that the KDM5s are necessary for mitotic clonal expansion in 3T3-L1 cells, indicating that KDM5 KD may interfere with differentiation in part by impairing proliferation. Notably, the demethylase activity of KDM5A is required for activation of at least a subset of pro-proliferative cell cycle genes. In conclusion, the KDM5 family acts as dual modulators of gene expression in preadipocytes and is required for early stage differentiation and activation of pro-proliferative cell cycle genes.
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Affiliation(s)
- Ann-Sofie B. Brier
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Anne Loft
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Jesper G. S. Madsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
- The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Thomas Rosengren
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Ronni Nielsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Søren F. Schmidt
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Zongzhi Liu
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Qin Yan
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Hinrich Gronemeyer
- Equipe Labellisée Ligue Contre le Cancer, Department of Functional Genomics and Cancer, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, UMR7104, Institut National de la Santé et de la Recherche Médicale, U964, Université de Strasbourg, Illkirch, France
| | - Susanne Mandrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
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12
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Schmidt SF, Madsen JGS, Frafjord KØ, Poulsen LLC, Salö S, Boergesen M, Loft A, Larsen BD, Madsen MS, Holst JJ, Maechler P, Dalgaard LT, Mandrup S. Integrative Genomics Outlines a Biphasic Glucose Response and a ChREBP-RORγ Axis Regulating Proliferation in β Cells. Cell Rep 2016; 16:2359-72. [PMID: 27545881 DOI: 10.1016/j.celrep.2016.07.063] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/26/2016] [Accepted: 07/25/2016] [Indexed: 12/27/2022] Open
Abstract
Glucose is an important inducer of insulin secretion, but it also stimulates long-term adaptive changes in gene expression that can either promote or antagonize the proliferative potential and function of β cells. Here, we have generated time-resolved profiles of enhancer and transcriptional activity in response to glucose in the INS-1E pancreatic β cell line. Our data outline a biphasic response with a first transcriptional wave during which metabolic genes are activated, and a second wave where cell-cycle genes are activated and β cell identity genes are repressed. The glucose-sensing transcription factor ChREBP directly activates first wave enhancers, whereas repression and activation of second wave enhancers are indirect. By integrating motif enrichment within late-regulated enhancers with expression profiles of the associated transcription factors, we have identified multiple putative regulators of the second wave. These include RORγ, the activity of which is important for glucose-induced proliferation of both INS-1E and primary rat β cells.
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Affiliation(s)
- Søren Fisker Schmidt
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Jesper Grud Skat Madsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark; NNF Center of Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Kari Østerli Frafjord
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Lars la Cour Poulsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Sofia Salö
- Department of Science and Environment, Roskilde University, 4000 Roskilde, Denmark
| | - Michael Boergesen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Anne Loft
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Bjørk Ditlev Larsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Maria Stahl Madsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Jens Juul Holst
- NNF Center of Basic Metabolic Research, University of Copenhagen, 2200 Copenhagen N, Denmark; Department of Biomedical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Pierre Maechler
- Department of Cell Physiology and Metabolism, University of Geneva, 1211 Geneva, Switzerland
| | - Louise Torp Dalgaard
- Department of Science and Environment, Roskilde University, 4000 Roskilde, Denmark
| | - Susanne Mandrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark.
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13
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Zhou Y, Zhang MJ, Li BH, Chen L, Pi Y, Yin YW, Long CY, Wang X, Sun MJ, Chen X, Gao CY, Li JC, Zhang LL. PPARγ Inhibits VSMC Proliferation and Migration via Attenuating Oxidative Stress through Upregulating UCP2. PLoS One 2016; 11:e0154720. [PMID: 27144886 PMCID: PMC4856345 DOI: 10.1371/journal.pone.0154720] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Accepted: 04/18/2016] [Indexed: 01/20/2023] Open
Abstract
Increasing evidence showed that abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) are common event in the pathophysiology of many vascular diseases, including atherosclerosis and restenosis after angioplasty. Among the underlying mechanisms, oxidative stress is one of the principal contributors to the proliferation and migration of VSMCs. Oxidative stress occurs as a result of persistent production of reactive oxygen species (ROS). Recently, the protective effects of peroxisome proliferator-activated receptor γ (PPARγ) against oxidative stress/ROS in other cell types provide new insights to inhibit the suggests that PPARγ may regulate VSMCs function. However, it remains unclear whether activation of PPARγ can attenuate oxidative stress and further inhibit VSMC proliferation and migration. In this study, we therefore investigated the effect of PPARγ on inhibiting VSMC oxidative stress and the capability of proliferation and migration, and the potential role of mitochondrial uncoupling protein 2 (UCP2) in oxidative stress. It was found that platelet derived growth factor-BB (PDGF-BB) induced VSMC proliferation and migration as well as ROS production; PPARγ inhibited PDGF-BB-induced VSMC proliferation, migration and oxidative stress; PPARγ activation upregulated UCP2 expression in VSMCs; PPARγ inhibited PDGF-BB-induced ROS in VSMCs by upregulating UCP2 expression; PPARγ ameliorated injury-induced oxidative stress and intimal hyperplasia (IH) in UCP2-dependent manner. In conclusion, our study provides evidence that activation of PPARγ can attenuate ROS and VSMC proliferation and migration by upregulating UCP2 expression, and thus inhibit IH following carotid injury. These findings suggest PPARγ may represent a prospective target for the prevention and treatment of IH-associated vascular diseases.
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Affiliation(s)
- Yi Zhou
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Ming-Jie Zhang
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Bing-Hu Li
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Lei Chen
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Yan Pi
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Yan-Wei Yin
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Chun-Yan Long
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Xu Wang
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Meng-Jiao Sun
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Xue Chen
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Chang-Yue Gao
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
| | - Jing-Cheng Li
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
- * E-mail: (L-LZ); (J-CL)
| | - Li-Li Zhang
- Department of Neurology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, 10 Changjiang Branch Road, Yuzhong District, Chongqing, 400042, PR China
- * E-mail: (L-LZ); (J-CL)
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14
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Christian M. Nuclear receptor-mediated regulation of lipid droplet-associated protein gene expression in adipose tissue. Horm Mol Biol Clin Investig 2016; 14:87-97. [PMID: 25436723 DOI: 10.1515/hmbci-2013-0028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 06/10/2013] [Indexed: 01/18/2023]
Abstract
In adipose tissues, nuclear receptors (NRs) have important metabolic actions on cellular lipid-storing capacity through targeted gene regulation. Lipid droplets (LDs) are the organelles for intracellular triacylglycerol (TAG) storage and are present in all eukaryotic cells. They are small in most cells, but in white adipocytes, they can occupy 90% of the cytoplasm. LDs consist of a TAG core surrounded by a phospholipid monolayer and an array of associated proteins that determine size, stability, inter-droplet interaction, and lipid storage capacity. The genes that encode these proteins are more highly expressed in brown compared with white fat, correlating with the greater LD surface area in multilocular brown adipocytes. Gene expression profiling reveals that most NRs are present in adipose tissues, with some showing greater expression in brown compared with white fat, including peroxisome proliferator-activated receptor (PPAR) α, estrogen-related receptor α, and NURR1. NR signaling is important for the regulated expression of most genes that encode LD-associated proteins. For example, estradiol signals via estrogen receptor α to regulate the levels of PLIN1 and the lipase ATGL controlling LD size and total lipid accumulation. PPARγ is essential for adipocyte differentiation and function, and analysis of data obtained through chromatin immunoprecipitation followed by high-throughput DNA sequencing shows that it binds to the promoters of many genes encoding LD proteins in adipocytes. Of these genes, the greatest PPARγ binding was to regulatory regions for Plin1, Cidec, and G0s2. NRs represent an important target for controlling LD dynamics in diseases affected by altered fat storage encompassing obesity and lipodystrophy, which are an increasing health problem.
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Affiliation(s)
- Mark Christian
- Division of Metabolic and Vascular Health, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK.
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15
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Watanabe M, Takahashi H, Saeki Y, Ozaki T, Itoh S, Suzuki M, Mizushima W, Tanaka K, Hatakeyama S. The E3 ubiquitin ligase TRIM23 regulates adipocyte differentiation via stabilization of the adipogenic activator PPARγ. eLife 2015; 4:e05615. [PMID: 25905670 PMCID: PMC4426667 DOI: 10.7554/elife.05615] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 04/21/2015] [Indexed: 12/19/2022] Open
Abstract
Adipocyte differentiation is a strictly controlled process regulated by a series of transcriptional activators. Adipogenic signals activate early adipogenic activators and facilitate the transient formation of early enhanceosomes at target genes. These enhancer regions are subsequently inherited by late enhanceosomes. PPARγ is one of the late adipogenic activators and is known as a master regulator of adipogenesis. However, the factors that regulate PPARγ expression remain to be elucidated. Here, we show that a novel ubiquitin E3 ligase, tripartite motif protein 23 (TRIM23), stabilizes PPARγ protein and mediates atypical polyubiquitin conjugation. TRIM23 knockdown caused a marked decrease in PPARγ protein abundance during preadipocyte differentiation, resulting in a severe defect in late adipogenic differentiation, whereas it did not affect the formation of early enhanceosomes. Our results suggest that TRIM23 plays a critical role in the switching from early to late adipogenic enhanceosomes by stabilizing PPARγ protein possibly via atypical polyubiquitin conjugation. DOI:http://dx.doi.org/10.7554/eLife.05615.001 The world is facing a global epidemic of obesity, which also increases the risk for diabetes and heart disease. Obesity is caused when excess fat is stored in fat cells, and overweight individuals have larger fat cells compared to healthy weight people. Therefore understanding how fat cells are created in the body can provide new ways to combat obesity. Fat cells, also known as adipocytes, arise from precursor cells via a process called adipogenesis. This requires the activity of proteins called transcription factors that bind to DNA and switch on the expression of genes. PPARγ is an important transcription factor that drives the expression of the genes that are needed to convert a precursor cell to a mature adipocyte. For adipogenesis to proceed, cells have to maintain the appropriate levels of PPARγ. If the amount of PPARγ bound to DNA is too low, then it is unable to activate gene expression. However, the mechanisms by which cells maintain the correct levels of PPARγ activity remain poorly understood. Watanabe et al. analyzed this process in mouse cells and identified a protein called TRIM23 that is produced in precursor cells. Cells in which the levels of TRIM23 were artificially lowered failed to mature into fat cells; this suggests that this protein is necessary for adipogenesis. Furthermore, in the absence of TRIM23, the amount of PPARγ that occupied regions of DNA was also markedly reduced. A direct consequence of this was a decline in the expression of several genes that are required for the later steps in the adipogenesis process. Watanabe et al. next analyzed the mechanism through which TRIM23 had an effect on the levels of PPARγ. It is known from previous work that TRIM23 belongs to a family of enzymes that attach a small molecular tag called ubiquitin onto other proteins. This ubiquitin tag typically marks these proteins for rapid destruction by a large molecular machine called the proteasome. Watanabe et al. found that TRIM23 also modified PPARγ with ubiquitin, but that it did so in an unusual manner that instead prevented the proteasome from recognizing PPARγ and destroying it. As such, TRIM23 stabilizes the levels of PPARγ in cells. By providing new insights into how adipogenesis is regulated, these findings suggest that TRIM23 may be a potential therapeutic target in the treatment of diabetes and disorders related to obesity. DOI:http://dx.doi.org/10.7554/eLife.05615.002
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Affiliation(s)
- Masashi Watanabe
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Hidehisa Takahashi
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Yasushi Saeki
- Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takashi Ozaki
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Shihori Itoh
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Masanobu Suzuki
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Wataru Mizushima
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Keiji Tanaka
- Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Shigetsugu Hatakeyama
- Department of Biochemistry, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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16
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Langhi C, Baldán Á. CIDEC/FSP27 is regulated by peroxisome proliferator-activated receptor alpha and plays a critical role in fasting- and diet-induced hepatosteatosis. Hepatology 2015; 61:1227-38. [PMID: 25418138 PMCID: PMC4376564 DOI: 10.1002/hep.27607] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 11/10/2014] [Indexed: 12/16/2022]
Abstract
UNLABELLED The cell death-inducing DNA fragmentation factor alpha-like effector c (CIDEC; also known in rodents as FSP27 or fat-specific protein 27) is a lipid droplet-associated protein that promotes intracellular triglyceride (TAG) storage. CIDEC/Fsp27 is highly expressed in adipose tissue, but undetectable in normal liver. However, its hepatic expression rises during fasting or under genetic or diet-induced hepatosteatosis in both mice and patients. Herein, we demonstrate that CIDEC/Fsp27 is a direct transcriptional target of the nuclear receptor PPARα (peroxisome proliferator-activated receptor alpha) in both mouse and human hepatocytes, and that preventing Fsp27 induction accelerates PPARα-stimulated fatty acid oxidation. We show that adenoviral-mediated silencing of hepatic Fsp27 abolishes fasting-induced liver steatosis in the absence of changes in plasma lipids. Finally, we report that anti-Fsp27 short hairpin RNA and PPARα agonists synergize to ameliorate hepatosteatosis in mice fed a high fat diet. CONCLUSIONS Together, our data highlight the physiological importance of CIDEC/Fsp27 in TAG homeostasis under both physiological and pathological liver steatosis. Our results also suggest that patients taking fibrates likely have elevated levels of hepatic CIDEC, which may limit the efficient mobilization and catabolism of hepatic TAGs.
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Affiliation(s)
- Cédric Langhi
- Edward A. Doisy Department of Biochemistry & Molecular Biology, Center for Cardiovascular Research, Saint Louis University, Saint Louis, MO
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17
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Loft A, Forss I, Siersbæk MS, Schmidt SF, Larsen ASB, Madsen JGS, Pisani DF, Nielsen R, Aagaard MM, Mathison A, Neville MJ, Urrutia R, Karpe F, Amri EZ, Mandrup S. Browning of human adipocytes requires KLF11 and reprogramming of PPARγ superenhancers. Genes Dev 2014; 29:7-22. [PMID: 25504365 PMCID: PMC4281566 DOI: 10.1101/gad.250829.114] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Long-term exposure to peroxisome proliferator-activated receptor γ (PPARγ) agonists such as rosiglitazone induces browning of rodent and human adipocytes; however, the transcriptional mechanisms governing this phenotypic switch in adipocytes are largely unknown. Here we show that rosiglitazone-induced browning of human adipocytes activates a comprehensive gene program that leads to increased mitochondrial oxidative capacity. Once induced, this gene program and oxidative capacity are maintained independently of rosiglitazone, suggesting that additional browning factors are activated. Browning triggers reprogramming of PPARγ binding, leading to the formation of PPARγ "superenhancers" that are selective for brown-in-white (brite) adipocytes. These are highly associated with key brite-selective genes. Based on such an association, we identified an evolutionarily conserved metabolic regulator, Kruppel-like factor 11 (KLF11), as a novel browning transcription factor in human adipocytes that is required for rosiglitazone-induced browning, including the increase in mitochondrial oxidative capacity. KLF11 is directly induced by PPARγ and appears to cooperate with PPARγ in a feed-forward manner to activate and maintain the brite-selective gene program.
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Affiliation(s)
- Anne Loft
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Isabel Forss
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Majken Storm Siersbæk
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Søren Fisker Schmidt
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Ann-Sofie Bøgh Larsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Jesper Grud Skat Madsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark; The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Didier F Pisani
- UMR 7277, Centre National de la Recherche Scientifique, U1091, Institut National de la Santé et de la Recherche Médicale, Institute of Biology Valrose, University Nice Sophia Antipolis, 06100 Nice, France
| | - Ronni Nielsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Mads Malik Aagaard
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Angela Mathison
- Laboratory of Epigenetics and Chromatin Dynamics, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Matt J Neville
- National Institute for Health Research, Oxford Biomedical Research Centre, OX3 7LE Oxford, United Kingdom
| | - Raul Urrutia
- Laboratory of Epigenetics and Chromatin Dynamics, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Fredrik Karpe
- National Institute for Health Research, Oxford Biomedical Research Centre, OX3 7LE Oxford, United Kingdom
| | - Ez-Zoubir Amri
- UMR 7277, Centre National de la Recherche Scientifique, U1091, Institut National de la Santé et de la Recherche Médicale, Institute of Biology Valrose, University Nice Sophia Antipolis, 06100 Nice, France
| | - Susanne Mandrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark;
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Donadelli M, Dando I, Fiorini C, Palmieri M. UCP2, a mitochondrial protein regulated at multiple levels. Cell Mol Life Sci 2014; 71:1171-90. [PMID: 23807210 PMCID: PMC11114077 DOI: 10.1007/s00018-013-1407-0] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 05/16/2013] [Accepted: 06/10/2013] [Indexed: 12/11/2022]
Abstract
An ever-increasing number of studies highlight the role of uncoupling protein 2 (UCP2) in a broad range of physiological and pathological processes. The knowledge of the molecular mechanisms of UCP2 regulation is becoming fundamental in both the comprehension of UCP2-related physiological events and the identification of novel therapeutic strategies based on UCP2 modulation. The study of UCP2 regulation is a fast-moving field. Recently, several research groups have made a great effort to thoroughly understand the various molecular mechanisms at the basis of UCP2 regulation. In this review, we describe novel findings concerning events that can occur in a concerted manner at various levels: Ucp2 gene mutation (single nucleotide polymorphisms), UCP2 mRNA and protein expression (transcriptional, translational, and protein turn-over regulation), UCP2 proton conductance (ligands and post-transcriptional modifications), and nutritional and pharmacological regulation of UCP2.
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Affiliation(s)
- Massimo Donadelli
- Section of Biochemistry, Deparment of Life and Reproduction Sciences, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy,
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Lysine deacetylase inhibition prevents diabetes by chromatin-independent immunoregulation and β-cell protection. Proc Natl Acad Sci U S A 2014; 111:1055-9. [PMID: 24395784 DOI: 10.1073/pnas.1320850111] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Type 1 diabetes is due to destruction of pancreatic β-cells. Lysine deacetylase inhibitors (KDACi) protect β-cells from inflammatory destruction in vitro and are promising immunomodulators. Here we demonstrate that the clinically well-tolerated KDACi vorinostat and givinostat revert diabetes in the nonobese diabetic (NOD) mouse model of type 1 diabetes and counteract inflammatory target cell damage by a mechanism of action consistent with transcription factor--rather than global chromatin--hyperacetylation. Weaning NOD mice received low doses of vorinostat and givinostat in their drinking water until 100-120 d of age. Diabetes incidence was reduced by 38% and 45%, respectively, there was a 15% increase in the percentage of islets without infiltration, and pancreatic insulin content increased by 200%. Vorinostat treatment increased the frequency of functional regulatory T-cell subsets and their transcription factors Gata3 and FoxP3 in parallel to a decrease in inflammatory dendritic cell subsets and their cytokines IL-6, IL-12, and TNF-α. KDACi also inhibited LPS-induced Cox-2 expression in peritoneal macrophages from C57BL/6 and NOD mice. In insulin-producing β-cells, givinostat did not upregulate expression of the anti-inflammatory genes Socs1-3 or sirtuin-1 but reduced levels of IL-1β + IFN-γ-induced proinflammatory Il1a, Il1b, Tnfα, Fas, Cxcl2, and reduced cytokine-induced ERK phosphorylation. Further, NF-κB genomic iNos promoter binding was reduced by 50%, and NF-κB-dependent mRNA expression was blocked. These effects were associated with NF-κB subunit p65 hyperacetylation. Taken together, these data provide a rationale for clinical trials of safety and efficacy of KDACi in patients with autoimmune disease such as type 1 diabetes.
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Peroxisome proliferator-activated receptor γ and C/EBPα synergistically activate key metabolic adipocyte genes by assisted loading. Mol Cell Biol 2013; 34:939-54. [PMID: 24379442 DOI: 10.1128/mcb.01344-13] [Citation(s) in RCA: 173] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα) are key activators of adipogenesis. They mutually induce the expression of each other and have been reported to cooperate in activation of a few adipocyte genes. Recently, genome-wide profiling revealed a high degree of overlap between PPARγ and C/EBPα binding in adipocytes, suggesting that cooperativeness could be mediated through common binding sites. To directly investigate the interplay between PPARγ and C/EBPα at shared binding sites, we established a fibroblastic model system in which PPARγ and C/EBPα can be independently expressed. Using RNA sequencing, we demonstrate that coexpression of PPARγ and C/EBPα leads to synergistic activation of many key metabolic adipocyte genes. This is associated with extensive C/EBPα-mediated reprogramming of PPARγ binding and vice versa in the vicinity of these genes, as determined by chromatin immunoprecipitation combined with deep sequencing. Our results indicate that this is at least partly mediated by assisted loading involving chromatin remodeling directed by the leading factor. In conclusion, we report a novel mechanism by which the key adipogenic transcription factors, PPARγ and C/EBPα, cooperate in activation of the adipocyte gene program.
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Haakonsson AK, Stahl Madsen M, Nielsen R, Sandelin A, Mandrup S. Acute genome-wide effects of rosiglitazone on PPARγ transcriptional networks in adipocytes. Mol Endocrinol 2013; 27:1536-49. [PMID: 23885096 DOI: 10.1210/me.2013-1080] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a master regulator of adipocyte differentiation, and genome-wide studies indicate that it is involved in the induction of most adipocyte genes. Here we report, for the first time, the acute effects of the synthetic PPARγ agonist rosiglitazone on the transcriptional network of PPARγ in adipocytes. Treatment with rosiglitazone for 1 hour leads to acute transcriptional activation as well as repression of a number of genes as determined by genome-wide RNA polymerase II occupancy. Unlike what has been shown for many other nuclear receptors, agonist treatment does not lead to major changes in the occurrence of PPARγ binding sites. However, rosiglitazone promotes PPARγ occupancy at many preexisting sites, and this is paralleled by increased occupancy of the mediator subunit MED1. The increase in PPARγ and MED1 binding is correlated with an increase in transcription of nearby genes, indicating that rosiglitazone, in addition to activating the receptor, also promotes its association with DNA, and that this is causally linked to recruitment of mediator and activation of genes. Notably, both rosiglitazone-activated and -repressed genes are induced during adipogenesis. However, rosiglitazone-activated genes are markedly more associated with PPARγ than repressed genes and are highly dependent on PPARγ for expression in adipocytes. By contrast, repressed genes are associated with the other key adipocyte transcription factor CCAAT-enhancer binding proteinα (C/EBPα), and their expression is more dependent on C/EBPα. This suggests that the relative occupancies of PPARγ and C/EBPα are critical for whether genes will be induced or repressed by PPARγ agonist.
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Affiliation(s)
- Anders Kristian Haakonsson
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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22
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Synthesis of N-(6-(4-(Piperazin-1-yl)phenoxy)pyridin-3-yl)benzenesulfonamide Derivatives for the Treatment of Metabolic Syndrome. INTERNATIONAL JOURNAL OF MEDICINAL CHEMISTRY 2013; 2013:201580. [PMID: 25374688 PMCID: PMC4207384 DOI: 10.1155/2013/201580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 10/16/2013] [Accepted: 10/24/2013] [Indexed: 11/17/2022]
Abstract
Metabolic syndrome is a widely prevalent multifactorial disorder associated with an increased risk of cardiovascular disease and type 2 diabetes mellitus. High plasma levels of insulin and glucose due to insulin resistance are a major component of the metabolic disorder. Thiazolidinediones (TZDs) are potent PPARγ ligand and used as insulin sensitizers in the treatment of type 2 diabetes mellitus. They are potent insulin-sensitizing agents but due to adverse effects like hepatotoxicity, a safer alternative of TZDs is highly demanded. Here we report synthesis of N-(6-(4-(piperazin-1-yl)phenoxy)pyridin-3-yl)benzenesulfonamide derivatives as an alternate remedy for insulin resistance.
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Abstract
Peroxisome proliferator-activated receptors (PPARs) are members of the steroid hormone receptor superfamily, discovered in 1990. To date, three PPAR subtypes have been identified; PPARα, PPAR β/δ, and PPARγ. These receptors share a high degree of homology but differ in tissue distribution and ligand specificity. PPARs have been implicated in the etiology as well as treatment of several important diseases and pathological conditions such as diabetes, inflammation, senescence-related diseases, regulation of fertility, and various types of cancer. Consequently, significant efforts to discover novel PPAR roles and delineate molecular mechanisms involved in their activation and repression as well as develop safer and more effective PPAR modulators, as therapeutic agents to treat a myriad of diseases and conditions, are underway. This volume of Methods in Molecular Biology contains details of experimental protocols used in researching these receptors.
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Affiliation(s)
- Jihan Youssef
- University of Missouri-Kansas City, Kansas City, MO, USA
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Osz J, Pethoukhov MV, Sirigu S, Svergun DI, Moras D, Rochel N. Solution Structures of PPARγ2/RXRα Complexes. PPAR Res 2012; 2012:701412. [PMID: 23319938 PMCID: PMC3539437 DOI: 10.1155/2012/701412] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 11/07/2012] [Accepted: 11/19/2012] [Indexed: 02/06/2023] Open
Abstract
PPARγ is a key regulator of glucose homeostasis and insulin sensitization. PPARγ must heterodimerize with its dimeric partner, the retinoid X receptor (RXR), to bind DNA and associated coactivators such as p160 family members or PGC-1α to regulate gene networks. To understand how coactivators are recognized by the functional heterodimer PPARγ/RXRα and to determine the topological organization of the complexes, we performed a structural study using small angle X-ray scattering of PPARγ/RXRα in complex with DNA from regulated gene and the TIF2 receptor interacting domain (RID). The solution structures reveal an asymmetry of the overall structure due to the crucial role of the DNA in positioning the heterodimer and indicate asymmetrical binding of TIF2 to the heterodimer.
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Affiliation(s)
- Judit Osz
- Department of Integrative Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de Recherche Scientifique (CNRS) UMR 7104, Institut National de Santé et de Recherche Médicale (INSERM) U964, Université de Strasbourg, 67404 Illkirch, France
| | - Maxim V. Pethoukhov
- The European Molecular Biology Laboratory, Hamburg Outstation, 22603 Hamburg, Germany
| | - Serena Sirigu
- Department of Integrative Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de Recherche Scientifique (CNRS) UMR 7104, Institut National de Santé et de Recherche Médicale (INSERM) U964, Université de Strasbourg, 67404 Illkirch, France
| | - Dmitri I. Svergun
- The European Molecular Biology Laboratory, Hamburg Outstation, 22603 Hamburg, Germany
| | - Dino Moras
- Department of Integrative Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de Recherche Scientifique (CNRS) UMR 7104, Institut National de Santé et de Recherche Médicale (INSERM) U964, Université de Strasbourg, 67404 Illkirch, France
| | - Natacha Rochel
- Department of Integrative Structural Biology, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de Recherche Scientifique (CNRS) UMR 7104, Institut National de Santé et de Recherche Médicale (INSERM) U964, Université de Strasbourg, 67404 Illkirch, France
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25
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Karbowska J, Kochan Z. Fat-reducing effects of dehydroepiandrosterone involve upregulation of ATGL and HSL expression, and stimulation of lipolysis in adipose tissue. Steroids 2012; 77:1359-65. [PMID: 22951290 DOI: 10.1016/j.steroids.2012.08.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 08/07/2012] [Indexed: 12/31/2022]
Abstract
Dehydroepiandrosterone (DHEA) reduces body fat in rodents and humans, and increases glycerol release from isolated rat epididymal adipocytes and human visceral adipose tissue explants. It suggests that DHEA stimulates triglyceride hydrolysis in adipose tissue; however, the mechanisms underlying this action are still unclear. We examined the effects of DHEA on the expression of adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL), the key enzymes of lipolysis, in rat epididymal white adipose tissue (eWAT). Male Wistar rats were fed a diet containing 0.6% DHEA for 2 weeks and eWAT was analyzed for mRNA and protein expression of ATGL and HSL, as well as mRNA expression of peroxisome proliferator-activated receptor γ 2 (PPARγ2) and its downstream target fatty acid translocase (FAT). Glycerol release from eWAT explants and serum free fatty acids (FFA) were also measured. Rats that received DHEA gained less weight, had 23% lower eWAT mass and 31% higher serum FFA levels than controls. Cultured explants of eWAT from DHEA-treated rats released 81% more glycerol than those from control rats. DHEA administration upregulated ATGL mRNA (1.62-fold, P<0.05) and protein (1.78-fold, P<0.05) expression as well as augmented HSL mRNA levels (1.36-fold, P<0.05) and Ser660 phosphorylation of HSL (2.49-fold, P<0.05). PPARγ2 and FAT mRNA levels were also increased in DHEA-treated rats (1.61-fold, P<0.05 and 2.16-fold, P<0.05; respectively). Moreover, ATGL, HSL, and FAT mRNA levels were positively correlated with PPARγ2 expression. This study demonstrates that DHEA promotes lipid mobilization in adipose tissue by increasing the expression and activity of ATGL and HSL. The effects of DHEA appear to be mediated, at least in part, via PPARγ2 activation, which in turn upregulates ATGL and HSL gene expression.
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Affiliation(s)
- Joanna Karbowska
- Department of Biochemistry, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland.
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26
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Rao JR, Keating DJ, Chen C, Parkington HC. Adiponectin increases insulin content and cell proliferation in MIN6 cells via PPARγ-dependent and PPARγ-independent mechanisms. Diabetes Obes Metab 2012; 14:983-9. [PMID: 22594400 DOI: 10.1111/j.1463-1326.2012.01626.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/14/2012] [Accepted: 04/16/2012] [Indexed: 11/28/2022]
Abstract
AIMS Adiponectin is an important adipokine whose levels are decreased in obesity despite increases in adipocyte mass. Studies in animal models implicate adiponectin as an insulin sensitizer in skeletal muscle and liver. Thiazolidinediones (TZDs) are insulin sensitizers and ligands for peroxisome proliferator-activated γ receptors (PPARγ) and these receptors are expressed in β cells where their activation promotes cell survival. We hypothesize that adiponectin promotes β cell survival by activating PPARγ. METHODS We used MIN6 cells to investigate the effect of adiponectin on PPARγ expression, β-cell proliferation, insulin synthesis and insulin secretion. RESULTS We demonstrate that MIN6 cells contain adiponectin receptors and that adiponectin activates PPARγ mRNA and protein expression. This increase in PPARγ expression is blocked by the PPARγ antagonist, GW9662, indicating a transcriptional feedback loop involving PPARγ activation of itself. Adiponectin causes a significant increase in insulin content and secretion and this occurs also via PPARγ activation due to the inhibitory effect of GW9662. Adiponectin also promotes MIN6 cell proliferation, however, this effect is independent of PPARγ activation. CONCLUSIONS Our results identify novel roles for the adipokine, adiponectin, in β-cells function. Adiponectin upregulates PPARγ expression, insulin content and insulin secretion through PPARγ-dependent mechanisms. Reductions in circulating adiponectin levels in obese individuals could therefore result in negative effects on β-cell function and this may have direct relevance to β-cell dysfunction in type 2 diabetes.
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Affiliation(s)
- J R Rao
- Prince Henry's Institute of Medical Research, Melbourne, Victoria, Australia
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27
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PPARγ, an important gene related to lipid metabolism and immunity in Megalobrama amblycephala: cloning, characterization and transcription analysis by GeNorm. Gene 2012; 512:321-30. [PMID: 23069845 DOI: 10.1016/j.gene.2012.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 10/03/2012] [Accepted: 10/04/2012] [Indexed: 11/20/2022]
Abstract
In order to be able to modulate and improve the function of PPARγ and decrease further some metabolic diseases of M. amblycephala, we have cloned and identified the full-length cDNA of PPARγ in M. amblycephala and examined its transcription patterns at different embryo developmental stages and in different tissues of adult and immature fish. We also accurately normalized seven reference genes by GeNorm and calculated their gene transcription normalization factors. The full-length of PPARγ was 1968 bp, consisting of 218 bp 5'-untranslated region, 1,533 bp open reading frame encoding 510 amino acids residues and 217 bp 3'-untranslated region. M. amblycephala PPARγ peptide was predicted to consist of 4 conserved domains, i.e. N-terminal domain, DNA-binding domain, ligand binding domain and flexible hinge region. PPARγ mRNAs were detected in all studied tissues of adult and immature fish including adipose tissue, gill, heart, liver, spleen, kidney, white muscle, intestine, brain and gonad. In adult fish, PPARγ transcription in liver was highest, followed by gills and it was lowest in female gonads. Moreover, the differences among liver, gill, intestine/brain, spleen/white muscle, kidney and female gonads were greatly significant (p<0.01). The transcription of PPARγ in male gonads was significantly higher than in female gonads (p<0.01). In immature fish, the transcription of PPARγ was highest in intestines followed by adipose tissue, and it was lowest in hearts and white muscles. A great difference was observed (p<0.01) in the transcription of PPARγ among adipose tissue, intestines, liver and heart/white muscles. At different embryo developmental stages, PPARγ transcription in unfertilized spermatozoa was greatly higher than in unfertilized ovum (p<0.01) and it was highest among different embryo developmental stages. The transcription of PPARγ increased gradually during 2 cells stage and 32 cells stage and then decreased until gastrula stage at which it was lowest. The transcription of PPARγ increased again on first day after hatching. There was a significant difference (p<0.01) in the transcription of PPARγ between 2 cells stage and 32 cells stage and it was same between 32 cells stage and gastrula stage. These results revealed that transcription of PPARγ showed a tissue-dependent regulation and a developmental-stage-dependent regulation that are valuable and helpful to improve the function of PPARγ and to decrease some metabolic diseases in the culture of M. amblycephala.
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Lundh M, Christensen DP, Damgaard Nielsen M, Richardson SJ, Dahllöf MS, Skovgaard T, Berthelsen J, Dinarello CA, Stevenazzi A, Mascagni P, Grunnet LG, Morgan NG, Mandrup-Poulsen T. Histone deacetylases 1 and 3 but not 2 mediate cytokine-induced beta cell apoptosis in INS-1 cells and dispersed primary islets from rats and are differentially regulated in the islets of type 1 diabetic children. Diabetologia 2012; 55:2421-31. [PMID: 22772764 DOI: 10.1007/s00125-012-2615-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Accepted: 05/10/2012] [Indexed: 01/04/2023]
Abstract
AIMS/HYPOTHESIS Histone deacetylases (HDACs) are promising pharmacological targets in cancer and autoimmune diseases. All 11 classical HDACs (HDAC1-11) are found in the pancreatic beta cell, and HDAC inhibitors (HDACi) protect beta cells from inflammatory insults. We investigated which HDACs mediate inflammatory beta cell damage and how the islet content of these HDACs is regulated in recent-onset type 1 diabetes. METHODS The rat beta cell line INS-1 and dispersed primary islets from rats, either wild type or HDAC1-3 deficient, were exposed to cytokines and HDACi. Molecular mechanisms were investigated using real-time PCR, chromatin immunoprecipitation and ELISA assays. Pancreases from healthy children and children with type 1 diabetes were assessed using immunohistochemistry and immunofluorescence. RESULTS Screening of 19 compounds with different HDAC selectivity revealed that inhibitors of HDAC1, -2 and -3 rescued INS-1 cells from inflammatory damage. Small hairpin RNAs against HDAC1 and -3, but not HDAC2, reduced pro-inflammatory cytokine-induced beta cell apoptosis in INS-1 and primary rat islets. The protective properties of specific HDAC knock-down correlated with attenuated cytokine-induced iNos expression but not with altered expression of the pro-inflammatory mediators Il1α, Il1β, Tnfα or Cxcl2. HDAC3 knock-down reduced nuclear factor κB binding to the iNos promoter and HDAC1 knock-down restored insulin secretion. In pancreatic sections from children with type 1 diabetes of recent onset, HDAC1 was upregulated in beta cells whereas HDAC2 and -3 were downregulated in comparison with five paediatric controls. CONCLUSIONS/INTERPRETATION These data demonstrate non-redundant functions of islet class I HDACs and suggest that targeting HDAC1 and HDAC3 would provide optimal protection of beta cell mass and function in clinical islet transplantation and recent-onset type 1 diabetic patients.
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Affiliation(s)
- M Lundh
- Center for Medical Research Methodology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark.
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Genome-wide profiling of peroxisome proliferator-activated receptor γ in primary epididymal, inguinal, and brown adipocytes reveals depot-selective binding correlated with gene expression. Mol Cell Biol 2012; 32:3452-63. [PMID: 22733994 DOI: 10.1128/mcb.00526-12] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a master regulator of adipocyte differentiation and function. We and others have previously mapped PPARγ binding at a genome-wide level in murine and human adipocyte cell lines and in primary human adipocytes. However, little is known about how binding patterns of PPARγ differ between brown and white adipocytes and among different types of white adipocytes. Here we have employed chromatin immunoprecipitation combined with deep sequencing to map and compare PPARγ binding in in vitro differentiated primary mouse adipocytes isolated from epididymal, inguinal, and brown adipose tissues. While these PPARγ binding profiles are overall similar, there are clear depot-selective binding sites. Most PPARγ binding sites previously mapped in 3T3-L1 adipocytes can also be detected in primary adipocytes, but there are a large number of PPARγ binding sites that are specific to the primary cells, and these tend to be located in closed chromatin regions in 3T3-L1 adipocytes. The depot-selective binding of PPARγ is associated with highly depot-specific gene expression. This indicates that PPARγ plays a role in the induction of genes characteristic of different adipocyte lineages and that preadipocytes from different depots are differentially preprogrammed to permit PPARγ lineage-specific recruitment even when differentiated in vitro.
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Bugge A, Feng D, Everett LJ, Briggs ER, Mullican SE, Wang F, Jager J, Lazar MA. Rev-erbα and Rev-erbβ coordinately protect the circadian clock and normal metabolic function. Genes Dev 2012; 26:657-67. [PMID: 22474260 DOI: 10.1101/gad.186858.112] [Citation(s) in RCA: 387] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The nuclear receptor Rev-erbα regulates circadian rhythm and metabolism, but its effects are modest and it has been considered to be a secondary regulator of the cell-autonomous clock. Here we report that depletion of Rev-erbα together with closely related Rev-erbβ has dramatic effects on the cell-autonomous clock as well as hepatic lipid metabolism. Mouse embryonic fibroblasts were rendered arrhythmic by depletion of both Rev-erbs. In mouse livers, Rev-erbβ mRNA and protein levels oscillate with a diurnal pattern similar to that of Rev-erbα, and both Rev-erbs are recruited to a remarkably similar set of binding sites across the genome, enriched near metabolic genes. Depletion of both Rev-erbs in liver synergistically derepresses several metabolic genes as well as genes that control the positive limb of the molecular clock. Moreover, deficiency of both Rev-erbs causes marked hepatic steatosis, in contrast to relatively subtle changes upon loss of either subtype alone. These findings establish the two Rev-erbs as major regulators of both clock function and metabolism, displaying a level of subtype collaboration that is unusual among nuclear receptors but common among core clock proteins, protecting the organism from major perturbations in circadian and metabolic physiology.
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Affiliation(s)
- Anne Bugge
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Department of Genetics, The Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Roforth MM, Liu G, Khosla S, Monroe DG. Examination of nuclear receptor expression in osteoblasts reveals Rorβ as an important regulator of osteogenesis. J Bone Miner Res 2012; 27:891-901. [PMID: 22189870 PMCID: PMC3667501 DOI: 10.1002/jbmr.1502] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A complex network of transcription factors contributes to the establishment and maintenance of the osteoblastic phenotype. Although relatively few transcription factors, such as Runx2 and osterix, are essential to the process of osteoblastic differentiation, others serve the purpose of fine-tuning in response to various environmental and hormonal cues. The nuclear receptor (NR) superfamily of transcription factors are involved in numerous aspects of bone biology. In this study, we characterized the expression pattern of the entire NR superfamily in differentiating primary murine calvarial cells in order to identify novel NR regulatory patterns. Dynamic patterns of NR expression were observed throughout the differentiation process. Interestingly, retinoic acid receptor-related orphan receptor β (Rorβ) expression was markedly suppressed at later stages of differentiation. To gain further insight into the function of NRs in bone biology, the NR superfamily was also profiled in mouse bone marrow precursor cells isolated from either young (6-month) or aging, osteoporotic (18-22-month) mice. Of interest, Rorβ was potently overexpressed in the aged cohort. Collectively, these data provided evidence that Rorβ expression is inversely correlated with osteogenic potential, suggesting Rorβ may be an important and unexplored regulator of osteogenesis. To validate this hypothesis, a cell model stably expressing Rorβ in mouse osteoblastic MC3T3-E1 cells was produced (MC3T3-Rorβ). These cells displayed markedly suppressed bone nodule formation as well as reduced osteocalcin and osterix gene expression. Because these genes are Runx2 targets, we reasoned that Rorβ may interfere with Runx2 activity. Consistent with this, transient transfection analysis demonstrated that Rorβ inhibited Runx2-dependent activation of a Runx2-reporter construct. In summary, our data provide a comprehensive profile of NR expression during osteoblast differentiation and identify Rorβ as a novel regulator of osteogenesis and potentially of age-related bone loss through antagonism of Runx2 activity.
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Affiliation(s)
- Matthew M Roforth
- Endocrine Research Unit, College of Medicine, Mayo Clinic, Rochester, MN 55905, USA
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32
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Hallenborg P, Feddersen S, Francoz S, Murano I, Sundekilde U, Petersen RK, Akimov V, Olson MV, Lozano G, Cinti S, Gjertsen BT, Madsen L, Marine JC, Blagoev B, Kristiansen K. Mdm2 controls CREB-dependent transactivation and initiation of adipocyte differentiation. Cell Death Differ 2012; 19:1381-9. [PMID: 22388350 DOI: 10.1038/cdd.2012.15] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The role of the E3 ubiquitin ligase murine double minute 2 (Mdm2) in regulating the stability of the p53 tumor suppressor is well documented. By contrast, relatively little is known about p53-independent activities of Mdm2 and the role of Mdm2 in cellular differentiation. Here we report a novel role for Mdm2 in the initiation of adipocyte differentiation that is independent of its ability to regulate p53. We show that Mdm2 is required for cAMP-mediated induction of CCAAT/enhancer-binding protein δ (C/EBPδ) expression by facilitating recruitment of the cAMP regulatory element-binding protein (CREB) coactivator, CREB-regulated transcription coactivator (Crtc2)/TORC2, to the c/ebpδ promoter. Our findings reveal an unexpected role for Mdm2 in the regulation of CREB-dependent transactivation during the initiation of adipogenesis. As Mdm2 is able to promote adipogenesis in the myoblast cell line C2C12, it is conceivable that Mdm2 acts as a switch in cell fate determination.
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Affiliation(s)
- P Hallenborg
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
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Bordicchia M, Liu D, Amri EZ, Ailhaud G, Dessì-Fulgheri P, Zhang C, Takahashi N, Sarzani R, Collins S. Cardiac natriuretic peptides act via p38 MAPK to induce the brown fat thermogenic program in mouse and human adipocytes. J Clin Invest 2012; 122:1022-36. [PMID: 22307324 DOI: 10.1172/jci59701] [Citation(s) in RCA: 668] [Impact Index Per Article: 55.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 11/16/2011] [Indexed: 02/06/2023] Open
Abstract
The ability of mammals to resist body fat accumulation is linked to their ability to expand the number and activity of "brown adipocytes" within white fat depots. Activation of β-adrenergic receptors (β-ARs) can induce a functional "brown-like" adipocyte phenotype. As cardiac natriuretic peptides (NPs) and β-AR agonists are similarly potent at stimulating lipolysis in human adipocytes, we investigated whether NPs could induce human and mouse adipocytes to acquire brown adipocyte features, including a capacity for thermogenic energy expenditure mediated by uncoupling protein 1 (UCP1). In human adipocytes, atrial NP (ANP) and ventricular NP (BNP) activated PPARγ coactivator-1α (PGC-1α) and UCP1 expression, induced mitochondriogenesis, and increased uncoupled and total respiration. At low concentrations, ANP and β-AR agonists additively enhanced expression of brown fat and mitochondrial markers in a p38 MAPK-dependent manner. Mice exposed to cold temperatures had increased levels of circulating NPs as well as higher expression of NP signaling receptor and lower expression of the NP clearance receptor (Nprc) in brown adipose tissue (BAT) and white adipose tissue (WAT). NPR-C(-/-) mice had markedly smaller WAT and BAT depots but higher expression of thermogenic genes such as Ucp1. Infusion of BNP into mice robustly increased Ucp1 and Pgc-1α expression in WAT and BAT, with corresponding elevation of respiration and energy expenditure. These results suggest that NPs promote "browning" of white adipocytes to increase energy expenditure, defining the heart as a central regulator of adipose tissue biology.
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Affiliation(s)
- Marica Bordicchia
- Metabolic Signaling and Disease Program, Diabetes and Obesity Research Center, Sanford-Burnham Medical Research Institute, Orlando, Florida 32827, USA
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Siersbæk R, Nielsen R, Mandrup S. Transcriptional networks and chromatin remodeling controlling adipogenesis. Trends Endocrinol Metab 2012; 23:56-64. [PMID: 22079269 DOI: 10.1016/j.tem.2011.10.001] [Citation(s) in RCA: 214] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 10/07/2011] [Accepted: 10/12/2011] [Indexed: 12/12/2022]
Abstract
Adipocyte differentiation is tightly controlled by a transcriptional cascade, which directs the extensive reprogramming of gene expression required to convert fibroblast-like precursor cells into mature lipid-laden adipocytes. Recent global analyses of transcription factor binding and chromatin remodeling have revealed 'snapshots' of this cascade and the chromatin landscape at specific time-points of differentiation. These studies demonstrate that multiple adipogenic transcription factors co-occupy hotspots characterized by an open chromatin structure and specific epigenetic modifications. Such transcription factor hotspots are likely to represent key signaling nodes which integrate multiple adipogenic signals at specific chromatin sites, thereby facilitating coordinated action on gene expression.
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Affiliation(s)
- Rasmus Siersbæk
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
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Harmon GS, Lam MT, Glass CK. PPARs and lipid ligands in inflammation and metabolism. Chem Rev 2012; 111:6321-40. [PMID: 21988241 DOI: 10.1021/cr2001355] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Gregory S Harmon
- Department of Medicine, Division of Digestive Diseases, University of California-Los Angeles, Los Angeles, California 90095, USA
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Poulsen LLC, Siersbæk M, Mandrup S. PPARs: fatty acid sensors controlling metabolism. Semin Cell Dev Biol 2012; 23:631-9. [PMID: 22273692 DOI: 10.1016/j.semcdb.2012.01.003] [Citation(s) in RCA: 340] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 01/09/2012] [Indexed: 12/13/2022]
Abstract
The peroxisome proliferator activated receptors (PPARs) are nuclear receptors that play key roles in the regulation of lipid metabolism, inflammation, cellular growth, and differentiation. The receptors bind and are activated by a broad range of fatty acids and fatty acid derivatives and they thereby serve as major transcriptional sensors of fatty acids. Here we review the function, regulation, and mechanism of the different PPAR subtypes with special emphasis on their role in the regulation of lipid metabolism.
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Affiliation(s)
- Lars la Cour Poulsen
- University of Southern Denmark, Department of Biochemistry and Molecular Biology, Campusvej 55, DK-5230, Odense M, Denmark.
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Gurevich I, Zhang C, Encarnacao PC, Struzynski CP, Livings SE, Aneskievich BJ. PPARγ and NF-κB regulate the gene promoter activity of their shared repressor, TNIP1. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1819:1-15. [PMID: 22001530 PMCID: PMC3249470 DOI: 10.1016/j.bbagrm.2011.09.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 09/27/2011] [Accepted: 09/30/2011] [Indexed: 11/27/2022]
Abstract
Human TNFAIP3 interacting protein 1 (TNIP1) has diverse functions including support of HIV replication through its interaction with viral Nef and matrix proteins, reduction of TNFα-induced signaling through its interaction with NF-κB pathway proteins, and corepression of agonist-bound retinoic acid receptors and peroxisome proliferator-activated receptors (PPAR). The wide tissue distribution of TNIP1 provides the opportunity to influence numerous cellular responses in these roles and defining control of TNIP1 expression would be central to improved understanding of its impact on cell function. We cloned 6kb of the human TNIP1 promoter and performed predictive and functional analyses to identify regulatory elements. The promoter region proximal to the transcription start site is GC-rich without a recognizable TATA box. In contrast to this proximal ~500bp region, 6kb of the promoter increased reporter construct constitutive activity over five-fold. Throughout the 6kb length, in silico analysis identified several potential binding sites for both constitutive and inducible transcription factors; among the latter were candidate NF-κB binding sequences and peroxisome proliferator response elements (PPREs). We tested NF-κB and PPAR regulation of the endogenous TNIP1 gene and cloned promoter by expression studies, electrophoretic mobility shift assays, and chromatin immunoprecipitations. We validated NF-κB sites in the TNIP1 promoter proximal and distal regions as well as one PPRE in the distal region. The ultimate control of the TNIP1 promoter is likely to be a combination of constitutive transcription factors and those subject to activation such as NF-κB and PPAR.
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Affiliation(s)
- Igor Gurevich
- Graduate Program in Pharmacology & Toxicology, University of Connecticut, Storrs, CT 06269-3092; USA
| | - Carmen Zhang
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT 06269-3092; USA
| | - Priscilla C. Encarnacao
- Graduate Program in Pharmacology & Toxicology, University of Connecticut, Storrs, CT 06269-3092; USA
| | - Charles P. Struzynski
- Doctor of Pharmacy Program, School of Pharmacy, University of Connecticut, Storrs, CT 06269-3092; USA
| | - Sarah E. Livings
- Doctor of Pharmacy Program, School of Pharmacy, University of Connecticut, Storrs, CT 06269-3092; USA
| | - Brian J. Aneskievich
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT 06269-3092; USA
- Center for Regenerative Biology, University of Connecticut, Storrs, CT 06269-3092; USA
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Genome-wide profiling of liver X receptor, retinoid X receptor, and peroxisome proliferator-activated receptor α in mouse liver reveals extensive sharing of binding sites. Mol Cell Biol 2011; 32:852-67. [PMID: 22158963 DOI: 10.1128/mcb.06175-11] [Citation(s) in RCA: 191] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The liver X receptors (LXRs) are nuclear receptors that form permissive heterodimers with retinoid X receptor (RXR) and are important regulators of lipid metabolism in the liver. We have recently shown that RXR agonist-induced hypertriglyceridemia and hepatic steatosis in mice are dependent on LXRs and correlate with an LXR-dependent hepatic induction of lipogenic genes. To further investigate the roles of RXR and LXR in the regulation of hepatic gene expression, we have mapped the ligand-regulated genome-wide binding of these factors in mouse liver. We find that the RXR agonist bexarotene primarily increases the genomic binding of RXR, whereas the LXR agonist T0901317 greatly increases both LXR and RXR binding. Functional annotation of putative direct LXR target genes revealed a significant association with classical LXR-regulated pathways as well as peroxisome proliferator-activated receptor (PPAR) signaling pathways, and subsequent chromatin immunoprecipitation-sequencing (ChIP-seq) mapping of PPARα binding demonstrated binding of PPARα to 71 to 88% of the identified LXR-RXR binding sites. The combination of sequence analysis of shared binding regions and sequential ChIP on selected sites indicate that LXR-RXR and PPARα-RXR bind to degenerate response elements in a mutually exclusive manner. Together, our findings suggest extensive and unexpected cross talk between hepatic LXR and PPARα at the level of binding to shared genomic sites.
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Kim HJ, Ham SA, Kim MY, Hwang JS, Lee H, Kang ES, Yoo T, Woo IS, Yabe-Nishimura C, Paek KS, Kim JH, Seo HG. PPARδ coordinates angiotensin II-induced senescence in vascular smooth muscle cells through PTEN-mediated inhibition of superoxide generation. J Biol Chem 2011; 286:44585-93. [PMID: 22072715 DOI: 10.1074/jbc.m111.222562] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cellular senescence-associated changes in blood vessels have been implicated in aging and age-related cardiovascular disorders. Here, we demonstrate that peroxisome proliferator-activated receptor (PPAR) δ coordinates angiotensin (Ang) II-induced senescence of human vascular smooth muscle cells (VSMCs). Activation of PPARδ by GW501516, a specific ligand for PPARδ, significantly attenuated Ang II-induced generation of superoxides and suppressed senescence of VSMCs. A marked increase in the levels of p53 and p21 induced by Ang II was blunted by the treatment with GW501516. Ligand-activated PPARδ up-regulated expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and suppressed the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. Knockdown of PTEN with siRNA abrogated the effects of PPARδ on cellular senescence, on PI3K/Akt signaling, and on generation of ROS in VSMCs treated with Ang II. Finally, administration of GW501516 to apoE-deficient mice treated with Ang II significantly reduced the number of senescent cells in the aorta, where up-regulation of PTEN with reduced levels of phosphorylated Akt and ROS was demonstrated. Thus, ligand-activated PPARδ confers resistance to Ang II-induced senescence by up-regulation of PTEN and ensuing modulation of the PI3K/Akt signaling to reduce ROS generation in vascular cells.
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Affiliation(s)
- Hyo Jung Kim
- Department of Animal Biotechnology, Konkuk University, Seoul 143-701, Korea
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Peroxisome Proliferator-Activated Receptor Delta: A Conserved Director of Lipid Homeostasis through Regulation of the Oxidative Capacity of Muscle. PPAR Res 2011; 2008:172676. [PMID: 18815630 PMCID: PMC2547483 DOI: 10.1155/2008/172676] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Revised: 07/10/2008] [Accepted: 08/13/2008] [Indexed: 12/13/2022] Open
Abstract
The peroxisome proliferator-activated receptors (PPARs), which are ligand-inducible transcription factors expressed in a variety of tissues, have been shown to perform key roles in lipid homeostasis. In physiological situations such as fasting and physical exercise, one PPAR subtype, PPARδ, triggers a transcriptional program in skeletal muscle leading to a switch in fuel usage from glucose/fatty acids to solely fatty acids, thereby drastically increasing its oxidative capacity. The metabolic action of PPARδ has also been verified in humans. In addition, it has become clear that the action of PPARδ is not restricted to skeletal muscle. Indeed, PPARδ has been shown to play a crucial role in whole-body lipid homeostasis as well as in insulin sensitivity, and it is active not only in skeletal muscle (as an activator of fat burning) but also in the liver (where it can activate glycolysis/lipogenesis, with the produced fat being oxidized in muscle) and in the adipose tissue (by incrementing lipolysis). The main aim of this review is to highlight the central role for activated PPARδ in the reversal of any tendency toward the development of insulin resistance.
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41
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Extensive chromatin remodelling and establishment of transcription factor 'hotspots' during early adipogenesis. EMBO J 2011; 30:1459-72. [PMID: 21427703 DOI: 10.1038/emboj.2011.65] [Citation(s) in RCA: 275] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 02/17/2011] [Indexed: 12/27/2022] Open
Abstract
Adipogenesis is tightly controlled by a complex network of transcription factors acting at different stages of differentiation. Peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein (C/EBP) family members are key regulators of this process. We have employed DNase I hypersensitive site analysis to investigate the genome-wide changes in chromatin structure that accompany the binding of adipogenic transcription factors. These analyses revealed a dramatic and dynamic modulation of the chromatin landscape during the first hours of adipocyte differentiation that coincides with cooperative binding of multiple early transcription factors (including glucocorticoid receptor, retinoid X receptor, Stat5a, C/EBPβ and -δ) to transcription factor 'hotspots'. Our results demonstrate that C/EBPβ marks a large number of these transcription factor 'hotspots' before induction of differentiation and chromatin remodelling and is required for their establishment. Furthermore, a subset of early remodelled C/EBP-binding sites persists throughout differentiation and is later occupied by PPARγ, indicating that early C/EBP family members, in addition to their well-established role in activation of PPARγ transcription, may act as pioneering factors for PPARγ binding.
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42
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Schmidt SF, Jørgensen M, Chen Y, Nielsen R, Sandelin A, Mandrup S. Cross species comparison of C/EBPα and PPARγ profiles in mouse and human adipocytes reveals interdependent retention of binding sites. BMC Genomics 2011; 12:152. [PMID: 21410980 PMCID: PMC3068983 DOI: 10.1186/1471-2164-12-152] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 03/16/2011] [Indexed: 01/01/2023] Open
Abstract
Background The transcription factors peroxisome proliferator activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα) are key transcriptional regulators of adipocyte differentiation and function. We and others have previously shown that binding sites of these two transcription factors show a high degree of overlap and are associated with the majority of genes upregulated during differentiation of murine 3T3-L1 adipocytes. Results Here we have mapped all binding sites of C/EBPα and PPARγ in human SGBS adipocytes and compared these with the genome-wide profiles from mouse adipocytes to systematically investigate what biological features correlate with retention of sites in orthologous regions between mouse and human. Despite a limited interspecies retention of binding sites, several biological features make sites more likely to be retained. First, co-binding of PPARγ and C/EBPα in mouse is the most powerful predictor of retention of the corresponding binding sites in human. Second, vicinity to genes highly upregulated during adipogenesis significantly increases retention. Third, the presence of C/EBPα consensus sites correlate with retention of both factors, indicating that C/EBPα facilitates recruitment of PPARγ. Fourth, retention correlates with overall sequence conservation within the binding regions independent of C/EBPα and PPARγ sequence patterns, indicating that other transcription factors work cooperatively with these two key transcription factors. Conclusions This study provides a comprehensive and systematic analysis of what biological features impact on retention of binding sites between human and mouse. Specifically, we show that the binding of C/EBPα and PPARγ in adipocytes have evolved in a highly interdependent manner, indicating a significant cooperativity between these two transcription factors.
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Affiliation(s)
- Søren F Schmidt
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
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43
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PPARs are a unique set of fatty acid regulated transcription factors controlling both lipid metabolism and inflammation. Biochim Biophys Acta Mol Basis Dis 2011; 1812:1007-22. [PMID: 21382489 PMCID: PMC3117990 DOI: 10.1016/j.bbadis.2011.02.014] [Citation(s) in RCA: 601] [Impact Index Per Article: 46.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 02/25/2011] [Accepted: 02/28/2011] [Indexed: 01/03/2023]
Abstract
Cells are constantly exposed to a large variety of lipids. Traditionally, these molecules were thought to serve as simple energy storing molecules. More recently it has been realized that they can also initiate and regulate signaling events that will decisively influence development, cellular differentiation, metabolism and related functions through the regulation of gene expression. Multicellular organisms dedicate a large family of nuclear receptors to these tasks. These proteins combine the defining features of both transcription factors and receptor molecules, and therefore have the unique ability of being able to bind lipid signaling molecules and transduce the appropriate signals derived from lipid environment to the level of gene expression. Intriguingly, the members of a subfamily of the nuclear receptors, the peroxisome proliferator-activated receptors (PPARs) are able to sense and interpret fatty acid signals derived from dietary lipids, pathogenic lipoproteins or essential fatty acid metabolites. Not surprisingly, Peroxisome proliferator-activated receptors were found to be key regulators of lipid and carbohydrate metabolism. Unexpectedly, later studies revealed that Peroxisome proliferator-activated receptors are also able to modulate inflammatory responses. Here we summarize our understanding on how these transcription factors/receptors connect lipid metabolism to inflammation and some of the novel regulatory mechanisms by which they contribute to homeostasis and certain pathological conditions. This article is part of a Special Issue entitled: Translating nuclear receptors from health to disease.
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Neess D, Bloksgaard M, Bek S, Marcher AB, Elle IC, Helledie T, Due M, Pagmantidis V, Finsen B, Wilbertz J, Kruhøffer M, Færgeman N, Mandrup S. Disruption of the acyl-CoA-binding protein gene delays hepatic adaptation to metabolic changes at weaning. J Biol Chem 2010; 286:3460-72. [PMID: 21106527 DOI: 10.1074/jbc.m110.161109] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The acyl-CoA-binding protein (ACBP)/diazepam binding inhibitor is an intracellular protein that binds C(14)-C(22) acyl-CoA esters and is thought to act as an acyl-CoA transporter. In vitro analyses have indicated that ACBP can transport acyl-CoA esters between different enzymatic systems; however, little is known about the in vivo function in mammalian cells. We have generated mice with targeted disruption of ACBP (ACBP(-/-)). These mice are viable and fertile and develop normally. However, around weaning, the ACBP(-/-) mice go through a crisis with overall weakness and a slightly decreased growth rate. Using microarray analysis, we show that the liver of ACBP(-/-) mice displays a significantly delayed adaptation to weaning with late induction of target genes of the sterol regulatory element-binding protein (SREBP) family. As a result, hepatic de novo cholesterogenesis is decreased at weaning. The delayed induction of SREBP target genes around weaning is caused by a compromised processing and decreased expression of SREBP precursors, leading to reduced binding of SREBP to target sites in chromatin. In conclusion, lack of ACBP interferes with the normal metabolic adaptation to weaning and leads to delayed induction of the lipogenic gene program in the liver.
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Affiliation(s)
- Ditte Neess
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
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45
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Molecular Mechanisms and Genome-Wide Aspects of PPAR Subtype Specific Transactivation. PPAR Res 2010; 2010. [PMID: 20862367 PMCID: PMC2938449 DOI: 10.1155/2010/169506] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Accepted: 06/27/2010] [Indexed: 12/13/2022] Open
Abstract
The peroxisome proliferator-activated receptors (PPARs) are central regulators of fat metabolism, energy homeostasis, proliferation, and inflammation. The three PPAR subtypes, PPARα, β/δ, and γ activate overlapping but also very different target gene programs. This review summarizes the insights into PPAR subtype-specific transactivation provided by genome-wide studies and discusses the recent advances in the understanding of the molecular mechanisms underlying PPAR subtype specificity with special focus on the regulatory role of AF-1.
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46
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Moreno M, Lombardi A, Silvestri E, Senese R, Cioffi F, Goglia F, Lanni A, de Lange P. PPARs: Nuclear Receptors Controlled by, and Controlling, Nutrient Handling through Nuclear and Cytosolic Signaling. PPAR Res 2010; 2010:435689. [PMID: 20814433 PMCID: PMC2929508 DOI: 10.1155/2010/435689] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Revised: 05/31/2010] [Accepted: 06/30/2010] [Indexed: 12/31/2022] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs), which are known to regulate lipid homeostasis, are tightly controlled by nutrient availability, and they control nutrient handling. In this paper, we focus on how nutrients control the expression and action of PPARs and how cellular signaling events regulate the action of PPARs in metabolically active tissues (e.g., liver, skeletal muscle, heart, and white adipose tissue). We address the structure and function of the PPARs, and their interaction with other nuclear receptors, including PPAR cross-talk. We further discuss the roles played by different kinase pathways, including the extracellular signal-regulated kinases/mitogen-activated protein kinase (ERK MAPK), AMP-activated protein kinase (AMPK), Akt/protein kinase B (Akt/PKB), and the NAD+-regulated protein deacetylase SIRT1, serving to control the activity of the PPARs themselves as well as that of a key nutrient-related PPAR coactivator, PPARgamma coactivator-1alpha (PGC-1alpha). We also highlight how currently applied nutrigenomic strategies will increase our understanding on how nutrients regulate metabolic homeostasis through PPAR signaling.
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Affiliation(s)
- Maria Moreno
- Dipartimento di Scienze Biologiche ed Ambientali, Università degli Studi del Sannio, Via Port'Arsa 11, 82100 Benevento, Italy
| | - Assunta Lombardi
- Dipartimento delle Scienze Biologiche, Sezione Fisiologia ed Igiene, Università degli Studi di Napoli “Federico II”, Via Mezzocannone 8, 80134 Napoli, Italy
| | - Elena Silvestri
- Dipartimento di Scienze Biologiche ed Ambientali, Università degli Studi del Sannio, Via Port'Arsa 11, 82100 Benevento, Italy
| | - Rosalba Senese
- Dipartimento di Scienze della Vita, Seconda Università degli Studi di Napoli, Via Vivaldi 43, 81100 Caserta, Italy
| | - Federica Cioffi
- Dipartimento di Scienze della Vita, Seconda Università degli Studi di Napoli, Via Vivaldi 43, 81100 Caserta, Italy
| | - Fernando Goglia
- Dipartimento di Scienze Biologiche ed Ambientali, Università degli Studi del Sannio, Via Port'Arsa 11, 82100 Benevento, Italy
| | - Antonia Lanni
- Dipartimento di Scienze della Vita, Seconda Università degli Studi di Napoli, Via Vivaldi 43, 81100 Caserta, Italy
| | - Pieter de Lange
- Dipartimento di Scienze della Vita, Seconda Università degli Studi di Napoli, Via Vivaldi 43, 81100 Caserta, Italy
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Pyper SR, Viswakarma N, Yu S, Reddy JK. PPARalpha: energy combustion, hypolipidemia, inflammation and cancer. NUCLEAR RECEPTOR SIGNALING 2010; 8:e002. [PMID: 20414453 PMCID: PMC2858266 DOI: 10.1621/nrs.08002] [Citation(s) in RCA: 292] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 03/04/2010] [Indexed: 12/11/2022]
Abstract
The peroxisome proliferator-activated receptor alpha (PPARalpha, or NR1C1) is a nuclear hormone receptor activated by a structurally diverse array of synthetic chemicals known as peroxisome proliferators. Endogenous activation of PPARalpha in liver has also been observed in certain gene knockout mouse models of lipid metabolism, implying the existence of enzymes that either generate (synthesize) or degrade endogenous PPARalpha agonists. For example, substrates involved in fatty acid oxidation can function as PPARalpha ligands. PPARalpha serves as a xenobiotic and lipid sensor to regulate energy combustion, hepatic steatosis, lipoprotein synthesis, inflammation and liver cancer. Mainly, PPARalpha modulates the activities of all three fatty acid oxidation systems, namely mitochondrial and peroxisomal beta-oxidation and microsomal omega-oxidation, and thus plays a key role in energy expenditure. Sustained activation of PPARalpha by either exogenous or endogenous agonists leads to the development of hepatocellular carcinoma resulting from sustained oxidative and possibly endoplasmic reticulum stress and liver cell proliferation. PPARalpha requires transcription coactivator PPAR-binding protein (PBP)/mediator subunit 1(MED1) for its transcriptional activity.
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Affiliation(s)
| | | | | | - Janardan K. Reddy
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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48
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Bugge A, Siersbaek M, Madsen MS, Göndör A, Rougier C, Mandrup S. A novel intronic peroxisome proliferator-activated receptor gamma enhancer in the uncoupling protein (UCP) 3 gene as a regulator of both UCP2 and -3 expression in adipocytes. J Biol Chem 2010; 285:17310-7. [PMID: 20360005 DOI: 10.1074/jbc.m110.120584] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Uncoupling Proteins (UCPs) are integral ion channels residing in the inner mitochondrial membrane. UCP2 is ubiquitously expressed, while UCP3 is found primarily in muscles and adipose tissue. Although the exact molecular mechanism of action is controversial, it is generally agreed that both homologues function to facilitate mitochondrial fatty acid oxidation. UCP2 and -3 expression is activated by the peroxisome proliferator-activated receptors (PPARs), but so far no PPAR response element has been reported in the vicinity of the Ucp2 and Ucp3 genes. Using genome-wide profiling of PPARgamma occupancy in 3T3-L1 adipocytes we demonstrate that PPARgamma associates with three chromosomal regions in the vicinity of the Ucp3 locus and weakly with a site in intron 1 of the Ucp2 gene. These sites are isolated from the nearest neighboring sites by >900 kb. The most prominent PPARgamma binding site in the Ucp2 and Ucp3 loci is located in intron 1 of the Ucp3 gene and is the only site that facilitates PPARgamma transactivation of a heterologous promoter. This site furthermore transactivates the endogenous Ucp3 promoter, and using chromatin conformation capture we show that it loops out to specifically interact with the Ucp2 promoter and intron 1. Our data indicate that PPARgamma transactivation of both UCP2 and -3 is mediated through this novel enhancer in Ucp3 intron 1.
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Affiliation(s)
- Anne Bugge
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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MED14 tethers mediator to the N-terminal domain of peroxisome proliferator-activated receptor gamma and is required for full transcriptional activity and adipogenesis. Mol Cell Biol 2010; 30:2155-69. [PMID: 20194623 DOI: 10.1128/mcb.01238-09] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The Mediator subunit MED1/TRAP220/DRIP205/PBP interacts directly with many nuclear receptors and was long thought to be responsible for tethering Mediator to peroxisome proliferator-activated receptor (PPAR)-responsive promoters. However, it was demonstrated recently that PPARgamma can recruit Mediator by MED1-independent mechanisms. Here, we show that target gene activation by ectopically expressed PPARgamma and PPARalpha is independent of MED1. Consistent with this finding, recruitment of PPARgamma, MED6, MED8, TATA box-binding protein (TBP), and RNA polymerase II (RNAPII) to the enhancer and proximal promoter of the PPARgamma target gene Fabp4 is also independent of MED1. Using a small interfering RNA (siRNA)-based approach, we identify MED14 as a novel critical Mediator component for PPARgamma-dependent transactivation, and we demonstrate that MED14 interacts directly with the N terminus of PPARgamma in a ligand-independent manner. Interestingly, MED14 knockdown does not affect the recruitment of PPARgamma, MED6, and MED8 to the Fabp4 enhancer but does reduce their occupancy of the Fabp4 proximal promoter. In agreement with the necessity of MED14 for PPARgamma transcriptional activity, we show that knockdown of MED14 impairs adipogenesis of 3T3-L1 cells. Thus, MED14 constitutes a novel anchoring point between Mediator and the N-terminal domain of PPARgamma that is necessary for functional PPARgamma-mediated recruitment of Mediator and transactivation of PPARgamma subtype-specific target genes.
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Kennedy A, Martinez K, Chung S, LaPoint K, Hopkins R, Schmidt SF, Andersen K, Mandrup S, McIntosh M. Inflammation and insulin resistance induced by trans-10, cis-12 conjugated linoleic acid depend on intracellular calcium levels in primary cultures of human adipocytes. J Lipid Res 2010; 51:1906-17. [PMID: 20154361 DOI: 10.1194/jlr.m005447] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We previously demonstrated that trans-10, cis-12 (10,12) conjugated linoleic acid (CLA) induced inflammation and insulin resistance in primary human adipocytes by activating nuclear factor kappaB (NFkappaB) and extracellular signal-related kinase (ERK) signaling. In this study, we demonstrated that the initial increase in intracellular calcium ([Ca2+]i) mediated by 10,12 CLA was attenuated by TMB-8, an inhibitor of calcium release from the endoplasmic reticulum (ER), by BAPTA, an intracellular calcium chelator, and by D609, a phospholipase C (PLC) inhibitor. Moreover, BAPTA, TMB-8, and D609 attenuated 10,12 CLA-mediated production of reactive oxygen species (ROS), activation of ERK1/2 and cJun-NH2-terminal kinase (JNK), and induction of inflammatory genes. 10,12 CLA-mediated binding of NFkappaB to the promoters of interleukin (IL)-8 and cyclooxygenase (COX)-2 and induction of calcium-calmodulin kinase II (CaMKII) beta were attenuated by TMB-8. KN-62, a CaMKII inhibitor, also suppressed 10,12 CLA-mediated ROS production and ERK1/2 and JNK activation. Additionally, KN-62 attenuated 10,12 CLA induction of inflammatory and integrated stress response genes, increase in prostaglandin F2alpha, and suppression of peroxisome proliferator activated receptor gamma protein levels and insulin-stimulated glucose uptake. These data suggest that 10,12 CLA increases inflammation and insulin resistance in human adipocytes, in part by increasing [Ca2+]i levels, particularly calcium from the ER.
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Affiliation(s)
- Arion Kennedy
- Department of Nutrition, University of North Carolina at Greensboro, Greensboro, NC, USA
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