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Marengo B, Bellora F, Ricciarelli R, De Ciucis C, Furfaro A, Leardi R, Colla R, Pacini D, Traverso N, Moretta A, Pronzato MA, Bottino C, Domenicotti C. Oxysterol mixture and, in particular, 27-hydroxycholesterol drive M2 polarization of human macrophages. Biofactors 2016; 42:80-92. [PMID: 26669587 DOI: 10.1002/biof.1243] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 10/17/2015] [Indexed: 11/08/2022]
Abstract
Macrophages play a crucial role in atherosclerosis progression. Classically activated M1 macrophages have been found in rupture-prone atherosclerotic plaques whereas alternatively activated macrophages, M2, localize in stable plaque. Macrophage accumulation of cholesterol and of its oxidized derivatives (oxysterols) leads to the formation of foam cells, a hallmark of atherosclerotic lesions. In this study, the effects of oxysterols in determining the functional polarization of human macrophages were investigated. Monocytes, purified from peripheral blood mononuclear cells of healthy donors, were differentiated into macrophages (M0) and treated with an oxysterol mixture, cholesterol, or ethanol, every 4 H for a total of 4, 8, and 12 H. The administration of the compounds was repeated in order to maintain the levels of oxysterols constant throughout the treatment. Compared with ethanol treatment, the oxysterol mixture decreased the surface expression of CD36 and CD204 scavenger receptors and reduced the amount of reactive oxygen species whereas it did not affect either cell viability or matrix metalloprotease-9 activity. Moreover, the oxysterol mixture increased the expression of both liver X receptor α and ATP-binding cassette transporter 1. An enhanced secretion of the immunoregulatory cytokine IL-10 accompanied these events. The results supported the hypothesis that the constant levels of oxysterols and, in particular, of 27-hydroxycholesterol stimulate macrophage polarization toward the M2 immunomodulatory functional phenotype, contributing to the stabilization of atherosclerotic plaques.
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Affiliation(s)
- Barbara Marengo
- Department of Experimental Medicine, University of Genoa, via L. B. Alberti 2, Genoa, Italy
| | - Francesca Bellora
- Department of Experimental Medicine, University of Genoa, via L. B. Alberti 2, Genoa, Italy
| | - Roberta Ricciarelli
- Department of Experimental Medicine, University of Genoa, via L. B. Alberti 2, Genoa, Italy
| | - Chiara De Ciucis
- Department of Experimental Medicine, University of Genoa, via L. B. Alberti 2, Genoa, Italy
| | | | - Riccardo Leardi
- Department of Pharmacy, University of Genoa, Viale Cembrano 4, Genoa, Italy
| | - Renata Colla
- Department of Experimental Medicine, University of Genoa, via L. B. Alberti 2, Genoa, Italy
| | - Davide Pacini
- Department of Internal Medicine, University of Genoa, Viale Benedetto XV 6, Genoa, Italy
| | - Nicola Traverso
- Department of Experimental Medicine, University of Genoa, via L. B. Alberti 2, Genoa, Italy
| | - Alessandro Moretta
- Department of Experimental Medicine, University of Genoa, via L. B. Alberti 2, Genoa, Italy
| | | | - Cristina Bottino
- Department of Experimental Medicine, University of Genoa, via L. B. Alberti 2, Genoa, Italy
- Giannina Gaslini Institute, via G. Gaslini 5, Genoa, Italy
| | - Cinzia Domenicotti
- Department of Experimental Medicine, University of Genoa, via L. B. Alberti 2, Genoa, Italy
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Hussein MA, Shrestha E, Ouimet M, Barrett TJ, Leone S, Moore KJ, Hérault Y, Fisher EA, Garabedian MJ. LXR-Mediated ABCA1 Expression and Function Are Modulated by High Glucose and PRMT2. PLoS One 2015; 10:e0135218. [PMID: 26288135 PMCID: PMC4545936 DOI: 10.1371/journal.pone.0135218] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 07/20/2015] [Indexed: 01/11/2023] Open
Abstract
High cholesterol and diabetes are major risk factors for atherosclerosis. Regression of atherosclerosis is mediated in part by the Liver X Receptor (LXR) through the induction of genes involved in cholesterol transport and efflux. In the context of diabetes, regression of atherosclerosis is impaired. We proposed that changes in glucose levels modulate LXR-dependent gene expression. Using a mouse macrophage cell line (RAW 264.7) and primary bone marrow derived macrophages (BMDMs) cultured in normal or diabetes relevant high glucose conditions we found that high glucose inhibits the LXR-dependent expression of ATP-binding cassette transporter A1 (ABCA1), but not ABCG1. To probe for this mechanism, we surveyed the expression of a host of chromatin-modifying enzymes and found that Protein Arginine Methyltransferase 2 (PRMT2) was reduced in high compared to normal glucose conditions. Importantly, ABCA1 expression and ABCA1-mediated cholesterol efflux were reduced in Prmt2-/- compared to wild type BMDMs. Monocytes from diabetic mice also showed decreased expression of Prmt2 compared to non-diabetic counterparts. Thus, PRMT2 represents a glucose-sensitive factor that plays a role in LXR-mediated ABCA1-dependent cholesterol efflux and lends insight to the presence of increased atherosclerosis in diabetic patients.
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Affiliation(s)
- Maryem A. Hussein
- Department of Microbiology, NYU School of Medicine, New York, New York, United States of America
| | - Elina Shrestha
- Department of Microbiology, NYU School of Medicine, New York, New York, United States of America
| | - Mireille Ouimet
- Department of Medicine, NYU School of Medicine, New York, New York, United States of America
| | - Tessa J. Barrett
- Department of Medicine, NYU School of Medicine, New York, New York, United States of America
| | - Sarah Leone
- Department of Microbiology, NYU School of Medicine, New York, New York, United States of America
| | - Kathryn J. Moore
- Department of Medicine, NYU School of Medicine, New York, New York, United States of America
| | - Yann Hérault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, 1 rue Laurent Fries, 67404, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France; Institut Clinique de la Souris, ICS, 1 rue Laurent Fries, 67404, Illkirch, France
| | - Edward A. Fisher
- Department of Medicine, NYU School of Medicine, New York, New York, United States of America
| | - Michael J. Garabedian
- Department of Microbiology, NYU School of Medicine, New York, New York, United States of America
- * E-mail:
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Mozzicafreddo M, Cuccioloni M, Bonfili L, Cecarini V, Palermo FA, Cocci P, Mosconi G, Capone A, Ricci I, Eleuteri AM, Angeletti M. Environmental pollutants directly affect the liver X receptor alpha activity: Kinetic and thermodynamic characterization of binding. J Steroid Biochem Mol Biol 2015; 152:1-7. [PMID: 25869557 DOI: 10.1016/j.jsbmb.2015.04.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 04/02/2015] [Accepted: 04/08/2015] [Indexed: 12/14/2022]
Abstract
Liver X receptor is a ligand-activated transcription factor, which is mainly involved in cholesterol homeostasis, bile acid and triglycerides metabolism, and, as recently discovered, in the glucose metabolism by direct regulation of liver glucokinase. Its modulation by exogenous factors, such as drugs, industrial by-products, and chemicals is documented. Owing to the abundance of these synthetic molecules in the environment, and to the established target role of this receptor, a number of representative compounds of phthalate, organophosphate and fibrate classes were tested as ligands/modulators of human liver X receptor, using an integrated approach, combining an in silico molecular docking technique with an optical SPR biosensor binding study. The compounds of interest were predicted and proved to target the oxysterols-binding site of human LXRα with measurable binding kinetic constants and with affinities ranging between 4.3 × 10(-7) and 4.3 × 10(-8)M. Additionally, non-cytotoxic concentration of these chemicals induced relevant changes in the LXRα gene expression levels and other target genes (SREBP-1c and LGK) in human liver hepatocellular carcinoma cell line (HepG2), as demonstrated by q-RT-PCR.
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Affiliation(s)
- Matteo Mozzicafreddo
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032 Italy.
| | | | - Laura Bonfili
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032 Italy
| | - Valentina Cecarini
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032 Italy
| | | | - Paolo Cocci
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032 Italy
| | - Gilberto Mosconi
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032 Italy
| | - Aida Capone
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032 Italy
| | - Irene Ricci
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032 Italy
| | - Anna Maria Eleuteri
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032 Italy
| | - Mauro Angeletti
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino 62032 Italy
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Forestier A, Douki T, De Rosa V, Béal D, Rachidi W. Combination of Aβ Secretion and Oxidative Stress in an Alzheimer-Like Cell Line Leads to the Over-Expression of the Nucleotide Excision Repair Proteins DDB2 and XPC. Int J Mol Sci 2015; 16:17422-44. [PMID: 26263968 PMCID: PMC4581200 DOI: 10.3390/ijms160817422] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 06/19/2015] [Accepted: 06/29/2015] [Indexed: 12/21/2022] Open
Abstract
Repair of oxidative DNA damage, particularly Base Excision Repair (BER), impairment is often associated with Alzheimer’s disease pathology. Here, we aimed at investigating the complete Nucleotide Excision Repair (NER), a DNA repair pathway involved in the removal of bulky DNA adducts, status in an Alzheimer-like cell line. The level of DNA damage was quantified using mass spectrometry, NER gene expression was assessed by qPCR, and the NER protein activity was analysed through a modified version of the COMET assay. Interestingly, we found that in the presence of the Amyloid β peptide (Aβ), NER factors were upregulated at the mRNA level and that NER capacities were also specifically increased following oxidative stress. Surprisingly, NER capacities were not differentially improved following a typical NER-triggering of ultraviolet C (UVC) stress. Oxidative stress generates a differential and specific DNA damage response in the presence of Aβ. We hypothesized that the release of NER components such as DNA damage binding protein 2 (DDB2) and Xeroderma Pigmentosum complementation group C protein (XPC) following oxidative stress might putatively involve their apoptotic role rather than DNA repair function.
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Affiliation(s)
- Anne Forestier
- Laboratoire Lésions des Acides Nucléiques, Université Joseph Fourier-Grenoble 1/CEA/Institut Nanoscience et Cryogénie/SCIB, UMR-E3, Grenoble, France.
| | - Thierry Douki
- Laboratoire Lésions des Acides Nucléiques, Université Joseph Fourier-Grenoble 1/CEA/Institut Nanoscience et Cryogénie/SCIB, UMR-E3, Grenoble, France.
| | - Viviana De Rosa
- Laboratoire Lésions des Acides Nucléiques, Université Joseph Fourier-Grenoble 1/CEA/Institut Nanoscience et Cryogénie/SCIB, UMR-E3, Grenoble, France.
| | - David Béal
- Laboratoire Lésions des Acides Nucléiques, Université Joseph Fourier-Grenoble 1/CEA/Institut Nanoscience et Cryogénie/SCIB, UMR-E3, Grenoble, France.
| | - Walid Rachidi
- Laboratoire Lésions des Acides Nucléiques, Université Joseph Fourier-Grenoble 1/CEA/Institut Nanoscience et Cryogénie/SCIB, UMR-E3, Grenoble, France.
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5
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Martínez D, Pentinat T, Ribó S, Daviaud C, Bloks VW, Cebrià J, Villalmanzo N, Kalko SG, Ramón-Krauel M, Díaz R, Plösch T, Tost J, Jiménez-Chillarón JC. In utero undernutrition in male mice programs liver lipid metabolism in the second-generation offspring involving altered Lxra DNA methylation. Cell Metab 2014; 19:941-51. [PMID: 24794974 DOI: 10.1016/j.cmet.2014.03.026] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 02/06/2014] [Accepted: 03/17/2014] [Indexed: 11/18/2022]
Abstract
Obesity and type 2 diabetes have a heritable component that is not attributable to genetic factors. Instead, epigenetic mechanisms may play a role. We have developed a mouse model of intrauterine growth restriction (IUGR) by in utero malnutrition. IUGR mice developed obesity and glucose intolerance with aging. Strikingly, offspring of IUGR male mice also developed glucose intolerance. Here, we show that in utero malnutrition of F1 males influenced the expression of lipogenic genes in livers of F2 mice, partly due to altered expression of Lxra. In turn, Lxra expression is attributed to altered DNA methylation of its 5' UTR region. We found the same epigenetic signature in the sperm of their progenitors, F1 males. Our data indicate that in utero malnutrition results in epigenetic modifications in germ cells (F1) that are subsequently transmitted and maintained in somatic cells of the F2, thereby influencing health and disease risk of the offspring.
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Affiliation(s)
- Débora Martínez
- Hospital Sant Joan de Deu, Pediatric Endocrinology, Esplugues de Llobregat, Barcelona 08950, Spain
| | - Thais Pentinat
- Hospital Sant Joan de Deu, Pediatric Endocrinology, Esplugues de Llobregat, Barcelona 08950, Spain
| | - Sílvia Ribó
- Hospital Sant Joan de Deu, Pediatric Endocrinology, Esplugues de Llobregat, Barcelona 08950, Spain
| | - Christian Daviaud
- Laboratory for Epigenetics and Environment, Centre National de Génotypage, CEA-Institute de Génomique, 91057 Evry CEDEX, France
| | - Vincent W Bloks
- Department of Pediatrics, Center for Liver, Digestive, and Metabolic Diseases, University Medical Center Groningen, University of Groningen, Groningen 9713 GZ, the Netherlands
| | - Judith Cebrià
- Hospital Sant Joan de Deu, Pediatric Endocrinology, Esplugues de Llobregat, Barcelona 08950, Spain
| | - Nuria Villalmanzo
- Hospital Sant Joan de Deu, Pediatric Endocrinology, Esplugues de Llobregat, Barcelona 08950, Spain
| | - Susana G Kalko
- Bioinformatics Core Facility, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Hospital Clínic de Barcelona, Universitat de Barcelona (UB), Barcelona 08036, Spain
| | - Marta Ramón-Krauel
- Hospital Sant Joan de Deu, Pediatric Endocrinology, Esplugues de Llobregat, Barcelona 08950, Spain
| | - Rubén Díaz
- Hospital Sant Joan de Deu, Pediatric Endocrinology, Esplugues de Llobregat, Barcelona 08950, Spain; Facultat de Medicina, Universitat de Barcelona (UB), Barcelona 08950, Spain
| | - Torsten Plösch
- Department of Obstetrics and Gynaecology, University Medical Center Groningen, University of Groningen, Groningen 9713 GZ, the Netherlands
| | - Jörg Tost
- Laboratory for Epigenetics and Environment, Centre National de Génotypage, CEA-Institute de Génomique, 91057 Evry CEDEX, France
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Fu Y, Mukhamedova N, Ip S, D'Souza W, Henley KJ, DiTommaso T, Kesani R, Ditiatkovski M, Jones L, Lane RM, Jennings G, Smyth IM, Kile BT, Sviridov D. ABCA12 regulates ABCA1-dependent cholesterol efflux from macrophages and the development of atherosclerosis. Cell Metab 2013; 18:225-38. [PMID: 23931754 DOI: 10.1016/j.cmet.2013.07.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 03/05/2013] [Accepted: 07/02/2013] [Indexed: 11/16/2022]
Abstract
ABCA12 is involved in the transport of ceramides in skin, but it may play a wider role in lipid metabolism. We show that, in Abca12-deficient macrophages, cholesterol efflux failed to respond to activation with LXR agonists. Abca12 deficiency caused a reduction in the abundance of Abca1, Abcg1, and Lxrβ. Overexpression of Lxrβ reversed the effects. Mechanistically, Abca12 deficiency did not affect expression of genes involved in cholesterol metabolism. Instead, a physical association between Abca1, Abca12, and Lxrβ proteins was established. Abca12 deficiency enhanced interaction between Abca1 and Lxrβ and the degradation of Abca1. Overexpression of ABCA12 in HeLa-ABCA1 cells increased the abundance and stability of ABCA1. Abca12 deficiency caused an accumulation of cholesterol in macrophages and the formation of foam cells, impaired reverse cholesterol transport in vivo, and increased the development of atherosclerosis in irradiated Apoe(-/-) mice reconstituted with Apoe(-/-)Abca12(-/-) bone marrow. Thus, ABCA12 regulates the cellular cholesterol metabolism via an LXRβ-dependent posttranscriptional mechanism.
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Affiliation(s)
- Ying Fu
- Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
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7
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Saneyasu T, Shiragaki M, Kurachi K, Kamisoyama H, Honda K. Effects of short-term refeeding on the expression of genes involved in lipid metabolism in chicks (Gallus gallus). Comp Biochem Physiol B Biochem Mol Biol 2013; 166:1-6. [PMID: 23769904 DOI: 10.1016/j.cbpb.2013.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 06/07/2013] [Accepted: 06/08/2013] [Indexed: 12/16/2022]
Abstract
The aim of this study was to analyze the expression patterns of key genes involved in lipid metabolism in response to feeding in chicks. A total of 18 thirteen day-old male chicks were fasted for 12h. The mRNA levels of the genes in the liver and white adipose tissue were analyzed after 0, 2, and 4h of refeeding. The mRNA levels of sterol regulatory element-binding protein (SREBP) 1, liver X receptor α, peroxisome proliferator-activated receptor (PPAR) γ, acetyl-CoA carboxylase α and fatty acid synthase were significantly increased after 2h of refeeding. In contrast, the mRNA levels of PPARα and carnitine palmitoyltransferase 1a were significantly decreased after 2h of refeeding. The mRNA level of acyl-CoA oxidase was significantly decreased after 4h of refeeding. The mRNA levels of cholesterol metabolism-related genes such as SREBP2 and 3-hydroxy-3-methylglutaryl-CoA reductase were significantly increased after 2h of refeeding. In the white adipose tissue, the mRNA level of PPARγ was significantly increased after 2h of refeeding, whereas the mRNA level of adipose triglyceride lipase was significantly decreased after 4h of refeeding. These results demonstrated that expression of lipid metabolism-related genes is regulated by short-term refeeding in chicks.
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Affiliation(s)
- Takaoki Saneyasu
- Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
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8
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Abstract
OBJECTIVE Selenium neutralizes interleukin-1β (IL-1β) induced inflammatory responses in chondrocytes. We investigated potential mechanisms for this through in vitro knock down of three major selenoproteins, Iodothyronine Deiodinase-2 (DIO2), Glutathione Peroxidase-1 (GPX1), and Thioredoxin Reductase-1 (TR1) in primary human chondrocytes. METHODS Primary human chondrocytes were transfected with scrambled small interfering ribonucleic acid (siRNA) or siRNA specific for DIO2, GPX1 and TR1. After 48 h, transfected cells were cultured in serum free media for 48 h, with or without 10 pg/ml IL-1β for the final 24h. The efficiency of siRNAs was confirmed by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) and Western blot analysis. The gene expression, by qRT-PCR, of cyclooxygenase-2 (COX2), IL-1β, and Liver X receptor (LXR) alpha and beta was evaluated to determine the impact of selenoprotein knockdown on inflammatory responses in chondrocytes. RESULTS The messenger RNA (mRNA) expression of DIO2, GPX1, and TR1 was significantly decreased by the specific siRNAs (reduced 56%, P=0.0004; 96%, P<0.0001; and 66%, P<0.0001, respectively). Suppression of DIO2, but not GPX1 or TR1, significantly increased (~2-fold) both basal (P=0.0005) and IL-1β induced (P<0.0001) COX2 gene expression. Similarly, suppression of DIO2 significantly increased (∼9-fold) IL-1β induced IL-1β gene expression (P=0.0056) and resulted in a 32% (P=0.0044) decrease in LXRα gene expression but no effect on LXRβ. CONCLUSIONS Suppression of the selenoprotein DIO2 resulted in strong pro-inflammatory effects with increased expression of inflammatory mediators, IL-1β and COX2, and decreased expression of LXRα suggesting that this may be the upstream target through which the anti-inflammatory effects of DIO2 are mediated.
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Affiliation(s)
- A W M Cheng
- Department of Pathology, Duke University Medical Center, Durham, NC 27710, USA
| | - M Bolognesi
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
| | - V B Kraus
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
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Kim YD, Kim YH, Cho YM, Kim DK, Ahn SW, Lee JM, Chanda D, Shong M, Lee CH, Choi HS. Metformin ameliorates IL-6-induced hepatic insulin resistance via induction of orphan nuclear receptor small heterodimer partner (SHP) in mouse models. Diabetologia 2012; 55:1482-94. [PMID: 22349108 DOI: 10.1007/s00125-012-2494-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 01/09/2012] [Indexed: 01/14/2023]
Abstract
AIMS/HYPOTHESIS IL-6 is a proinflammatory cytokine associated with the pathogenesis of hepatic diseases. Metformin is an anti-diabetic drug used for the treatment of type 2 diabetes, and orphan nuclear receptor small heterodimer partner (SHP, also known as NR0B2), a transcriptional co-repressor, plays an important role in maintaining metabolic homeostasis. Here, we demonstrate that metformin-mediated activation of AMP-activated protein kinase (AMPK) increases SHP protein production and regulates IL-6-induced hepatic insulin resistance. METHODS We investigated metformin-mediated SHP production improved insulin resistance through the regulation of an IL-6-dependent pathway (involving signal transducer and activator of transcription 3 [STAT3] and suppressor of cytokine signalling 3 [SOCS3]) in both Shp knockdown and Shp null mice. RESULTS IL-6-induced STAT3 transactivation and SOCS3 production were significantly repressed by metformin, adenoviral constitutively active AMPK (Ad-CA-AMPK), and adenoviral SHP (Ad-SHP), but not in Shp knockdown, or with the adenoviral dominant negative form of AMPK (Ad-DN-AMPK). Chromatin immunoprecipitation (ChIP), co-immunoprecipitation (Co-IP) and protein localisation studies showed that SHP inhibits DNA binding of STAT3 on the Socs3 gene promoter via interaction and colocalisation within the nucleus. Upregulation of inflammatory genes and downregulation of hepatic insulin signalling by acute IL-6 treatment were observed in wild-type mice but not in Shp null mice. Finally, chronic IL-6 exposure caused hepatic insulin resistance, leading to impaired insulin tolerance and elevated gluconeogenesis, and these phenomena were aggravated in Shp null mice. CONCLUSIONS/INTERPRETATION Our results demonstrate that SHP upregulation by metformin may prevent hepatic disorders by regulating the IL-6-dependent pathway, and that this pathway can help to ameliorate the pathogenesis of cytokine-mediated metabolic dysfunction.
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Affiliation(s)
- Y D Kim
- National Creative Research Initiatives Center for Nuclear Receptor Signals, Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea
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10
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Wilkinson J, Hallis T, Hermanson S, Bi K. Development and validation of a cell-based assay for the nuclear receptor retinoid-related orphan receptor gamma. Assay Drug Dev Technol 2010; 9:125-35. [PMID: 21050030 DOI: 10.1089/adt.2010.0290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The nuclear receptor retinoid-related orphan receptor gamma (RORγ) has become an attractive target for drug discovery due to its important role in the development and differentiation of Th17 cells, a subset of T cells that produce interleukin-17 and are involved in the pathogenesis of human inflammatory and autoimmune diseases. To facilitate the drug discovery efforts in this area, we have developed a cellular assay for screening for RORγ inverse agonists. We stably engineered a tetracycline-inducible Gal4 DNA-binding domain/RORγ ligand-binding domain fusion protein into an upstream activation sequence driven-beta-lactamase reporter gene cell line. Due to its constitutive activity, the induced Gal4-RORγ expression leads to increased reporter activity, which can be knocked down using RORγ ligand-binding domain-specific RNA interference oligos. Using this assay, we tested several recently reported ligands for RORγ and observed varying levels of partial inverse agonist activity at μM concentrations. Additionally, we screened a small library of biologically active compounds with this assay and demonstrated its robustness and usefulness in high-throughput screening and follow-up studies for this emerging drug target.
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Pivovarova EN, Baginskaia NV, Perepechaeva ML, Il'nitskaia SI, Dushkin MI. [Expression of nuclear hormone receptors PPAR, LXR and RXR in the liver and lipid and glucose levels in blood in susceptible and resistant to hepatocarcinogenesis mice strains]. Biomed Khim 2010; 56:480-489. [PMID: 21032898 DOI: 10.18097/pbmc20105604480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Earlier it was shown that male mice of the DD/He strain were highly susceptible to ortho-aminoasotoluene (OAT) induced hepatocarcinogenesis, and resistant to spontaneous liver tumor development as compared to the CC57BR/Mv strain. In the present work we have made a comparative investigation of peroxisome proliferator-activated receptor (PPAR), liver X-receptor (LXR) and retinoic X-receptor (RXR) mRNA levels in liver as well as concentrations of corticosterone, glucose, lipids and insulin in blood of male DD/He and CC57BR/Mv mice. Using the multiplex RT-PCR method it was found that PPAR-alpha, PPAR-gamma, RXR-alpha and RXR-beta mRNA content was essentially decreased in the liver of DD mice as compared to mice of the CC57BR strain. No significant interstrain differences of LXR-alpha and LXR-beta mRNA content were found. In DD micetere was more then the 3-fold decrease of blood content of corticosterone, which is involved in PPAR and RXR regulation. DD mice demonstrated a significant decrease in blood serum glucose and insulin concentrations as well as higher reactivity to insulin as compared with CC57BR mice. Elevated blood total cholesterol and cholesterol HDL level were found in DD mice whereas triglyceride content was basically the same in both mouse strains. It is known that glucocorticoids, PPAR and RXR play crucial role in transcription regulation of inflammation response. Therefore our data allow to suggest that decreased corticosterone level in blood, PPAR and RXR mRNA content in liver of the DD strain may lead to induction of inflammation by OAT exposure, resulting in a high incidence of tumorigenesis in this strain.
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Ford CT, Sherratt MJ, Griffiths CEM, Watson REB. Liver X receptor β: maintenance of epidermal expression in intrinsic and extrinsic skin aging. Age (Dordr) 2009; 31:365-372. [PMID: 19697157 PMCID: PMC2813049 DOI: 10.1007/s11357-009-9111-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Accepted: 07/27/2009] [Indexed: 05/28/2023]
Abstract
Aging in human skin is the composite of time-dependent intrinsic aging plus photoaging induced by chronic exposure to ultraviolet radiation. Nuclear hormone receptors coordinate diverse processes including metabolic homeostasis. Liver X receptor β (LXRβ) is a close human homologue of daf-12, a regulator of nematode longevity. LXRβ is positively regulated by sirtuin-1 and resveratrol, while LXRβ-null mice show transcriptional profiles similar to those seen in aged human skin. In these studies, we examined LXRβ expression in aged and photoaged human skin. Volunteers were recruited to assess intrinsic aging and photoaging. Epidermal LXRβ mRNA was examined by in situ hybridization while protein was identified by immunofluorescence. No significant changes were observed in either LXRβ mRNA or protein expression between young and aged volunteers (mRNA p = 0.90; protein p = 0.26). Similarly, LXRβ protein expression was unaltered in photoaged skin (p = 0.75). Our data therefore suggest that, while not playing a major role in skin aging, robust cutaneous expression implies a fundamental role for LXRβ in epidermal biology.
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Affiliation(s)
- Christopher T. Ford
- Dermatological Sciences, The University of Manchester, 1.443 Stopford Building, Oxford Road, Manchester, M13 9PT UK
| | - Michael J. Sherratt
- Tissue Injury and Repair, The University of Manchester, 1.443 Stopford Building, Oxford Road, Manchester, M13 9PT UK
| | - Christopher E. M. Griffiths
- Dermatological Sciences, The University of Manchester, 1.443 Stopford Building, Oxford Road, Manchester, M13 9PT UK
| | - Rachel E. B. Watson
- Dermatological Sciences, The University of Manchester, 1.443 Stopford Building, Oxford Road, Manchester, M13 9PT UK
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