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Sun J, Luo J, Ruan Y, Xiu L, Fang B, Zhang H, Wang M, Chen H. Free Fatty Acids Activate Renin-Angiotensin System in 3T3-L1 Adipocytes through Nuclear Factor-kappa B Pathway. J Diabetes Res 2016; 2016:1587594. [PMID: 26881238 PMCID: PMC4736205 DOI: 10.1155/2016/1587594] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 10/20/2015] [Indexed: 01/22/2023] Open
Abstract
The activity of a local renin-angiotensin system (RAS) in the adipose tissue is closely associated with obesity-related diseases. However, the mechanism of RAS activation in adipose tissue is still unknown. In the current study, we found that palmitic acid (PA), one kind of free fatty acid, induced the activity of RAS in 3T3-L1 adipocytes. In the presence of fetuin A (Fet A), PA upregulated the expression of angiotensinogen (AGT) and angiotensin type 1 receptor (AT1R) and stimulated the secretion of angiotensin II (ANG II) in 3T3-L1 adipocytes. Moreover, the activation of RAS in 3T3-L1 adipocytes was blocked when we blocked Toll-like receptor 4 (TLR4) signaling pathway using TAK242 or NF-κB signaling pathway using BAY117082. Together, our results have identified critical molecular mechanisms linking PA/TLR4/NF-κB signaling pathway to the activity of the local renin-angiotensin system in adipose tissue.
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Affiliation(s)
- Jia Sun
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Jinhua Luo
- Department of Geratology, The Affiliated Hospital of Guangdong Medical College, Guangdong Medical College, Zhanjiang, Guangdong, China
| | - Yuting Ruan
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Liangchang Xiu
- Department of Epidemiology and Medical Statistics, School of Public Health, Guangdong Medical College, Dongguan, Guangdong, China
| | - Bimei Fang
- Second Clinical School of Medicine, Southern Medical University, Guangzhou, China
| | - Hua Zhang
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Ming Wang
- Nephrology Center of Integrated Traditional Chinese and Western Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- *Ming Wang: and
| | - Hong Chen
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
- *Hong Chen:
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Bays H, Blonde L, Rosenson R. Adiposopathy: how do diet, exercise and weight loss drug therapies improve metabolic disease in overweight patients? Expert Rev Cardiovasc Ther 2014; 4:871-95. [PMID: 17173503 DOI: 10.1586/14779072.4.6.871] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
An increase in bodyweight is generally associated with an increased risk of excessive fat-related metabolic diseases (EFRMD), including Type 2 diabetes mellitus, hypertension and dyslipidemia. However, not all patients who are overweight have EFRMD, and not all patients with EFRMD are significantly overweight. The adipocentric paradigm provides the basis for a unifying, pathophysiological process whereby fat gain in susceptible patients leads to fat dysfunction ('sick fat'), and wherein pathological abnormalities in fat function (adiposopathy) are more directly related to the onset of EFRMD than increases in fat mass (adiposity) alone. But just as worsening fat function worsens EFRMD, improved fat function improves EFRMD. Peroxisome proliferator-activated receptor-gamma agonists increase the recruitment, proliferation and differentiation of preadipocytes ('healthy fat') and cause apoptosis of hypertrophic and dysfunctional (including visceral) adipocytes resulting in improved fat function and improved metabolic parameters associated with EFRMD. Weight loss interventions, such as a hypocaloric diet and physical exercise, in addition to agents such as orlistat, sibutramine and cannabinoid receptor antagonists, may have favorable effects upon fat storage (lipogenesis and fat distribution), nutrient metabolism (such as free fatty acids), favorable effects upon adipose tissue factors involved in metabolic processes and inflammation, and enhanced 'cross-talk' with other major organ systems. In some cases, weight loss therapeutic agents may even affect metabolic parameters and adipocyte function independently of weight loss alone, suggesting that the benefit of these agents in improving EFRMD may go beyond their efficacy in weight reduction. This review describes how adiposopathy interventions may affect fat function, and thus improve EFRMD.
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Affiliation(s)
- Harold Bays
- L-MARC Research Center, Medical Director/President, 3288 Illinois Avenue, Louisville, KY 40213, USA.
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Marcus Y, Shefer G, Stern N. Adipose tissue renin-angiotensin-aldosterone system (RAAS) and progression of insulin resistance. Mol Cell Endocrinol 2013; 378:1-14. [PMID: 22750719 DOI: 10.1016/j.mce.2012.06.021] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 06/24/2012] [Indexed: 12/31/2022]
Abstract
This review focuses on the expression of the key components of the renin-angiotensin-aldosterone axis in fat tissue. At the center of this report is the role of RAAS in normal and excessive fat mass enlargement, the leading etiology of insulin resistance. Understanding the expression and regulation of RAAS components in various fat depots allows insight not only into the processes by which these complex patterns are modified by the enlargement of adipose tissue, but also into their impact on local and systemic response to insulin.
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Affiliation(s)
- Yonit Marcus
- Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, Tel Aviv 64239, Israel
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Kawahito H, Yamada H, Irie D, Kato T, Akakabe Y, Kishida S, Takata H, Wakana N, Ogata T, Ikeda K, Ueyama T, Matoba S, Mori Y, Matsubara H. Periaortic adipose tissue-specific activation of the renin-angiotensin system contributes to atherosclerosis development in uninephrectomized apoE-/- mice. Am J Physiol Heart Circ Physiol 2013; 305:H667-75. [PMID: 23812390 DOI: 10.1152/ajpheart.00053.2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chronic kidney disease (CKD) is an independent risk factor for the development of cardiovascular disease. The perivascular adipose tissue is closely implicated in the development of atherosclerosis; however, the contribution to CKD-associated atherogenesis remains undefined. Eight-week-old apoE-deficient mice were uninephrectomized and fed a high-cholesterol diet starting at 12 wk of age. The atherosclerotic lesion area in the thoracic aorta was comparable in 16-wk-old uninephrectomized (UNX) mice and sham control mice; however, the lesion area was markedly exaggerated in 20-wk-old UNX mice compared with the control (54%, P < 0.05). While the accumulation of monocytes/macrophages and the mRNA expression levels of inflammatory cytokines/chemokines in the thoracic periaortic adipose tissue (PAT) did not differ between the two groups, angiotensinogen (AGT) mRNA expression and the angiotensin II (ANG II) concentration in the PAT were significantly higher in 16-wk-old UNX mice than in the control (1.9- and 1.5-fold increases vs. control, respectively; P < 0.05). ANG II concentrations in both the plasma and epididymal white adipose tissue (WAT) were comparable between the two groups, suggesting that PAT-specific activation of the renin-angiotensin system (RAS) is primarily involved in CKD-associated atherogenesis. The homeostasis model assessment-insulin resistance (HOMA-IR) index and plasma insulin level after glucose loading were significantly elevated in 16-wk-old UNX mice. In vitro stimulation of preadipocytes with insulin exaggerated the AGT mRNA expression along with increased mRNA expression of PPARγ. These findings suggest that PAT-specific RAS activation probably primarily contributes in accelerating atherosclerotic development in UNX mice and could thus represent a therapeutic target for preventing CKD-associated atherogenesis.
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Affiliation(s)
- Hiroyuki Kawahito
- Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan; and
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Kalupahana NS, Moustaid-Moussa N. The adipose tissue renin-angiotensin system and metabolic disorders: a review of molecular mechanisms. Crit Rev Biochem Mol Biol 2012; 47:379-90. [PMID: 22720713 DOI: 10.3109/10409238.2012.694843] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The renin-angiotensin system (RAS) is classically known for its role in regulation of blood pressure, fluid and electrolyte balance. In this system, angiotensinogen (Agt), the obligate precursor of all bioactive angiotensin peptides, undergoes two enzymatic cleavages by renin and angiotensin converting enzyme (ACE) to produce angiotensin I (Ang I) and angiotensin II (Ang II), respectively. The contemporary view of RAS has become more complex with the discovery of additional angiotensin degradation pathways such as ACE2. All components of the RAS are expressed in and have independent regulation of adipose tissue. This local adipose RAS exerts important auto/paracrine functions in modulating lipogenesis, lipolysis, adipogenesis as well as systemic and adipose tissue inflammation. Mice with adipose-specific Agt overproduction have a 30% increase in plasma Agt levels and develop hypertension and insulin resistance, while mice with adipose-specific Agt knockout have a 25% reduction in Agt plasma levels, demonstrating endocrine actions of adipose RAS. Emerging evidence also points towards a role of RAS in regulation of energy balance. Because adipose RAS is overactivated in many obesity conditions, it is considered a potential candidate linking obesity to hypertension, insulin resistance and other metabolic derangements.
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Affiliation(s)
- Nishan S Kalupahana
- Obesity Research Center, The University of Tennessee (UT), Knoxville, TN, USA
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Uno K, Yamada T, Ishigaki Y, Imai J, Hasegawa Y, Gao J, Kaneko K, Matsusue K, Yamazaki T, Oka Y, Katagiri H. Hepatic peroxisome proliferator-activated receptor-γ-fat-specific protein 27 pathway contributes to obesity-related hypertension via afferent vagal signals. Eur Heart J 2011; 33:1279-89. [PMID: 21825308 DOI: 10.1093/eurheartj/ehr265] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
AIMS Obesity is commonly associated with hypertension. Increased sympathetic tonus in obese subjects contributes to the underlying mechanism. However, the precise mechanisms whereby obesity induces this sympathetic activation remain unclear. Hepatic peroxisome proliferator-activated receptor (PPAR)-γ2 expression, which is reportedly upregulated during obesity development, affects sympathetic activation via hepatic vagal afferents. Herein, we report involvement of this neuronal relay in obesity-related hypertension. METHODS AND RESULTS Peroxisome proliferator-activated receptor-γ and a direct PPARγ target, fat-specific protein 27 (Fsp27), were adenovirally overexpressed or knocked down in the liver, in combination with surgical dissection or pharmacological deafferentation of the hepatic vagus. Adenoviral PPARγ2 expression in the liver raised blood pressure (BP) in wild-type but not in β1/β2/β3 adrenergic receptor-deficient mice. In addition, knockdown of endogenous PPARγ in the liver lowered BP in murine obesity models. Either surgical dissection or pharmacological deafferentation of the hepatic vagus markedly blunted BP elevation in mice with diet-induced and genetically-induced obesity. In contrast, BP was not elevated in other models of hepatic steatosis, DGAT1 and DGAT2 overexpressions, in which PPARγ is not upregulated in the liver. Thus, hepatic PPARγ upregulation associated with obesity is involved in BP elevation during obesity development. Furthermore, hepatic expression of Fsp27 raised BP and the effect was blocked by hepatic vagotomy. Hepatic Fsp27 is actually upregulated in murine obesity models and its knockdown reversed BP elevation. CONCLUSION The hepatic PPARγ-Fsp27 pathway plays important roles in the development of obesity-related hypertension via afferent vagal signals from the liver.
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Affiliation(s)
- Kenji Uno
- Department of Metabolic Diseases, Center for Metabolic Diseases, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Japan
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Abstract
Several reviews have highlighted the importance of local tissue production of components of the renin-angiotensin system (RAS) [Bader, M., Ganten, D., 2008. Update on tissue renin-angiotensin systems. J. Mol. Med. 86, 615-621; Krop, M., Danser, A.H., 2008. Circulating versus tissue renin-angiotensin system: on the origin of (pro)renin. Curr. Hypertens. Rep. 10, 112-118; Paul, M., Poyan Mehr, A., Kreutz, R., 2006. Physiology of local renin-angiotensin systems. Physiol. Rev. 86, 747-803]. While the concept of tissue RAS is gaining more widespread acceptance, the concept of local angiotensin II (AngII) production, acting in coordinate or independently of the endocrine RAS, continues to be debated. The primary reasons that local AngII production has been studied by many investigators are that components of the RAS are expressed by multiple cell types, and that the endocrine RAS cannot fully explain all effects of AngII. Moreover, through the development and study of genetically altered models for over-expression or knockdown of individual RAS components within specific cell types, it is becoming increasingly more evident that local RAS contribute to effects of AngII in normal physiology and disease. The purpose of this review is to define the presence and physiological significance of a local RAS in adipose tissue in relation to cardiovascular disease.
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Affiliation(s)
- Sean Thatcher
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY 40536-0200, USA
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Lu H, Boustany-Kari CM, Daugherty A, Cassis LA. Angiotensin II increases adipose angiotensinogen expression. Am J Physiol Endocrinol Metab 2007; 292:E1280-7. [PMID: 17213477 DOI: 10.1152/ajpendo.00277.2006] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In addition to the well-defined contribution of the liver, adipose tissue has been recognized as an important source of angiotensinogen (AGT). The purpose of this study was to define the angiotensin II (ANG II) receptors involved in regulation of adipose AGT and the relationship of this control to systemic AGT and/or angiotensin peptide concentrations. In LDL receptor-deficient (LDLR(-/-)) male mice, adipose mRNA abundance of AGT was 68% of that in liver, and adipose mRNA abundance of the angiotensin type 1a (AT(1a)) receptor (AT(1a)R) was 38% of that in liver, whereas mRNA abundance of the angiotensin type 2 (AT(2)) receptor (AT(2)R) was 57% greater in adipose tissue than in liver. AGT and angiotensin peptide concentrations were decreased in plasma of AT(1a)R-deficient (AT(1a)R(-/-)) mice and were paralleled by reductions in AGT expression in liver. In contrast, adipose AGT mRNA abundance was unaltered in AT(1a)R(-/-) mice. AT(2)R(-/-) mice exhibited elevated plasma angiotensin peptide concentrations and marked elevations in adipose AGT and AT(1a)R mRNA abundance. Increases in adipose AGT mRNA abundance in AT(2)R(-/-) mice were abolished by losartan. In contrast, liver AGT and AT(1a)R mRNA abundance were unaltered in AT(2)R(-/-) mice. Infusion of ANG II for 28 days into LDLR(-/-) mice markedly increased adipose AGT and AT(1a)R mRNA but did not alter liver AGT and AT(1a)R mRNA. These results demonstrate that differential mRNA abundance of AT(1a)/AT(2) receptors in adipose tissue vs. liver contributes to tissue-specific ANG II-mediated regulation of AGT. Chronic infusion of ANG II robustly stimulated AT(1a)R and AGT mRNA abundance in adipose tissue, suggesting that adipose tissue serves as a primary contributor to the activated systemic renin-angiotensin system.
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MESH Headings
- Adipose Tissue/metabolism
- Adipose Tissue/physiology
- Angiotensin II/biosynthesis
- Angiotensin II/genetics
- Angiotensin II/metabolism
- Angiotensin II Type 1 Receptor Blockers/pharmacology
- Angiotensinogen/antagonists & inhibitors
- Angiotensinogen/biosynthesis
- Angiotensinogen/genetics
- Animals
- Blotting, Western
- Gene Expression Regulation
- Liver/metabolism
- Liver/physiology
- Losartan/pharmacology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptor, Angiotensin, Type 1/deficiency
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Receptor, Angiotensin, Type 2/deficiency
- Receptor, Angiotensin, Type 2/genetics
- Receptor, Angiotensin, Type 2/metabolism
- Receptors, LDL/genetics
- Receptors, LDL/metabolism
- Renin-Angiotensin System/genetics
- Renin-Angiotensin System/physiology
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Hong Lu
- Cardiovascular Research Center, Gill Heart Institute, University of Kentucky, Lexington, Kentucky 4053-0200, USA
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Bays H, Ballantyne C. Adiposopathy: why do adiposity and obesity cause metabolic disease? ACTA ACUST UNITED AC 2006. [DOI: 10.2217/17460875.1.4.389] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Abstract
BACKGROUND There is evidence that malnutrition in early life induces a growth retardation leading, in adult life, to manifest components of the metabolic syndrome. However, the impact on obesity seems less clearly established. OBJECTIVE To review the effects of foetal and postnatal malnutrition on the programming of obesity in the context of the metabolic syndrome, as well as the link between central obesity and cardiovascular diseases. METHODS Included in the review were recent papers exploring the mechanisms linking maternal nutrition with impaired foetal growth and later obesity, cardiovascular disease, hypertension and diabetes in humans and animals. RESULTS The programming of obesity during foetal and early postnatal life depends of the timing of maternal malnutrition as well as the postnatal environment. Obesity arises principally in offspring submitted to malnutrition during early stages of gestation and which presented early catch-up growth. The programming may involve the dysregulation of appetite control or the hormonal environment leading to a context favourable to obesity development (hypersecretion of corticosteroids, hyperinsulinaemia and hyperleptinaemia and anomalies in the IGF axis). Adipose tissue secretes actively several factors implicated in inflammation, blood pressure, coagulation and fibrinolysis. The programmed development of intra-abdominal obesity after early growth restriction may thus favour higher prevalence of hypertension and cardiovascular diseases. CONCLUSIONS Abdominal obesity appears in malnourished offspring and is aggravated by early catch-up growth. Higher rates of intra-abdominal obesity observed after growth restriction may participate to hypertension and create atherothrombotic conditions leading to the development of cardiovascular diseases.
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Affiliation(s)
- C Remacle
- Laboratory of Cell Biology, Institute of Life Science, Université Catholique de Louvain, Louvain-la-Neuve B 1348, Belgium.
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Serazin V, Dos Santos E, Morot M, Giudicelli Y. Human adipose angiotensinogen gene expression and secretion are stimulated by cyclic AMP via increased DNA cyclic AMP responsive element binding activity. Endocrine 2004; 25:97-104. [PMID: 15711021 DOI: 10.1385/endo:25:2:097] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 09/29/2004] [Accepted: 10/11/2004] [Indexed: 11/11/2022]
Abstract
Components of the adipose renin-angiotensin system (RAS) have been suggested as providing a potential path-way linking obesity to hypertension. In adipose cells, the biological responses to beta-adrenergic stimulation are mediated by an increase in intracellular cAMP. Because an association exists among body fat mass, hypertension, and increased sympathetic stimulation, we examined the influence of cAMP on angiotensinogen (ATG) expression and secretion in human adipose tissue and in parallel we studied the DNA binding activity of CRE transcriptional factors. A 24 h exposure to the cAMP analog 8Br-cAMP resulted in significant increases in ATG mRNA levels (+176+/-60%) and protein secretion (+40+/-27%). The ability of 8Br-cAMP to promote ATG gene expression was unaltered by H89, a protein kinase A inhibitor, because H89 per se was found to stimulate ATG mRNA levels and protein secretion. Moreover, 8Br-cAMP stimulated the specific CRE DNA binding activity (+115+/-14%) in human adipocyte nuclear extracts as assessed by electrophoretic mobility shift assays. These results indicate that cAMP upregulates in vitro ATG expression and secretion in human adipose tissue and that the induction in ATG mRNA levels appears to result, at least in part, from positive effects on the DNA binding activity of CRE transcription factors. Further studies are required to determine whether this regulatory pathway is activated in human obesity and to elucidate the importance of adipose ATG to the elevated blood pressure observed in this pathological state.
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Affiliation(s)
- Valérie Serazin
- Laboratoire de Biochimie et de Biologie Moléculaire de la Faculté de Médecine Paris-Ile-de-France-Ouest, UPRES EA 2493, Université Versailles Saint Quentin en Yvelines, and Hôpital de Poissy, F78303 Poissy Cedex France
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