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Ahmed F, Vranic M, Hetty S, Mathioudaki A, Patsoukaki V, Fanni G, Pereira MJ, Eriksson JW. Increased OCT3 Expression in Adipose Tissue With Aging: Implications for Catecholamine and Lipid Turnover and Insulin Resistance in Women. Endocrinology 2023; 165:bqad172. [PMID: 37972266 PMCID: PMC10690730 DOI: 10.1210/endocr/bqad172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 11/09/2023] [Accepted: 11/09/2023] [Indexed: 11/19/2023]
Abstract
BACKGROUND Catecholamine-stimulated lipolysis is reduced with aging, which may promote adiposity and insulin resistance. Organic cation transporter 3 (OCT3), which is inhibited by estradiol (E2), mediates catecholamine transport into adipocytes for degradation, thus decreasing lipolysis. In this study, we investigated the association of OCT3 mRNA levels in subcutaneous adipose tissue (SAT) with aging and markers of insulin resistance in women. METHODS SAT biopsies were obtained from 66 women with (19) or without (47) type 2 diabetes (age 22-76 years, 20.0-40.1 kg/m2). OCT3 mRNA and protein levels were measured for group comparisons and correlation analysis. SAT was incubated with E2 and OCT3 mRNA levels were measured. Associations between OCT3 single nucleotide polymorphisms (SNPs) and diabetes-associated traits were assessed. RESULTS OCT3 mRNA and protein levels in SAT increased with aging. SAT from postmenopausal women had higher levels of OCT3 than premenopausal women, and there was a dose-dependent reduction in OCT3 mRNA levels in SAT treated with E2. OCT3 mRNA levels were negatively associated with markers of insulin resistance, and ex vivo lipolysis. OCT3 SNPs were associated with BMI, waist to hip ratio, and circulating lipids (eg, triglycerides). CONCLUSION OCT3 mRNA and protein levels in SAT increased with aging, and mRNA levels were negatively associated with markers of insulin resistance. E2 incubation downregulated OCT3 mRNA levels, which may explain lower OCT3 mRNA in premenopausal vs postmenopausal women. High OCT3 protein levels in adipose tissue may result in increased catecholamine degradation, and this can contribute to the reduction in lipolysis observed in women with aging.
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Affiliation(s)
- Fozia Ahmed
- Department of Medical Sciences, Clinical Diabetology and Metabolism, Uppsala University, 751 85 Uppsala, Sweden
| | - Milica Vranic
- Department of Medical Sciences, Clinical Diabetology and Metabolism, Uppsala University, 751 85 Uppsala, Sweden
| | - Susanne Hetty
- Department of Medical Sciences, Clinical Diabetology and Metabolism, Uppsala University, 751 85 Uppsala, Sweden
| | - Argyri Mathioudaki
- Department of Medical Sciences, Clinical Diabetology and Metabolism, Uppsala University, 751 85 Uppsala, Sweden
| | - Vagia Patsoukaki
- Department of Medical Sciences, Clinical Diabetology and Metabolism, Uppsala University, 751 85 Uppsala, Sweden
| | - Giovanni Fanni
- Department of Medical Sciences, Clinical Diabetology and Metabolism, Uppsala University, 751 85 Uppsala, Sweden
| | - Maria J Pereira
- Department of Medical Sciences, Clinical Diabetology and Metabolism, Uppsala University, 751 85 Uppsala, Sweden
| | - Jan W Eriksson
- Department of Medical Sciences, Clinical Diabetology and Metabolism, Uppsala University, 751 85 Uppsala, Sweden
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Joung HY, Oh JM, Song MS, Kwon YB, Chun S. Selegiline Modulates Lipid Metabolism by Activating AMPK Pathways of Epididymal White Adipose Tissues in HFD-Fed Obese Mice. Pharmaceutics 2023; 15:2539. [PMID: 38004519 PMCID: PMC10675427 DOI: 10.3390/pharmaceutics15112539] [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: 09/26/2023] [Revised: 10/24/2023] [Accepted: 10/25/2023] [Indexed: 11/26/2023] Open
Abstract
Obesity, as a major cause of many chronic diseases such as diabetes, cardiovascular disease, and cancer, is among the most serious health problems. Increased monoamine oxidase (MAO) activity has been observed in the adipose tissue of obese humans and animals. Although previous studies have already demonstrated the potential of MAO-B inhibitors as a treatment for this condition, the mechanism of their effect has been insufficiently elucidated. In this study, we investigated the anti-obesity effect of selegiline, a selective MAO-B inhibitor, using in vivo animal models. The effect was evaluated through an assessment of body energy homeostasis, glucose tolerance tests, and biochemical analysis. Pharmacological inhibition of MAO-B by selegiline was observed to reduce body weight and fat accumulation, and improved glucose metabolism without a corresponding change in food intake, in HFD-fed obese mice. We also observed that both the expression of adipogenenic markers, including C/EBPα and FABP4, and lipogenic markers such as pACC were significantly reduced in epididymal white adipose tissues (eWATs). Conversely, increased expression of lipolytic markers such as ATGL and pHSL and AMPK phosphorylation were noted. Treating obese mice with selegiline significantly increased expression levels of UCP1 and promoted eWAT browning, indicating increased energy expenditure. These results suggest that selegiline, by inhibiting MAO-B activity, is a potential anti-obesity treatment.
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Affiliation(s)
- Hye-Young Joung
- Department of Physiology, Jeonbuk National University Medical School, Jeonju 54907, Republic of Korea; (H.-Y.J.); (J.-M.O.)
| | - Jung-Mi Oh
- Department of Physiology, Jeonbuk National University Medical School, Jeonju 54907, Republic of Korea; (H.-Y.J.); (J.-M.O.)
- Research Institute for Endocrine Sciences, Jeonbuk National University Medical School, Jeonju 54907, Republic of Korea
| | - Min-Suk Song
- Department of Microbiology, Chungbuk National University College of Medicine and Medical Research Institute, Cheongju 28644, Republic of Korea;
| | - Young-Bae Kwon
- Department of Pharmacology, Jeonbuk National University Medical School, Jeonju 54907, Republic of Korea;
| | - Sungkun Chun
- Department of Physiology, Jeonbuk National University Medical School, Jeonju 54907, Republic of Korea; (H.-Y.J.); (J.-M.O.)
- Research Institute for Endocrine Sciences, Jeonbuk National University Medical School, Jeonju 54907, Republic of Korea
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Effects of Chemical Structures Interacting with Amine Oxidases on Glucose, Lipid and Hydrogen Peroxide Handling by Human Adipocytes. Molecules 2022; 27:molecules27196224. [PMID: 36234761 PMCID: PMC9571511 DOI: 10.3390/molecules27196224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/07/2022] [Accepted: 09/19/2022] [Indexed: 11/26/2022] Open
Abstract
Benzylamine is a natural molecule present in food and edible plants, capable of activating hexose uptake and inhibiting lipolysis in human fat cells. These effects are dependent on its oxidation by amine oxidases present in adipocytes, and on the subsequent hydrogen peroxide production, known to exhibit insulin-like actions. Virtually, other substrates interacting with such hydrogen peroxide-releasing enzymes potentially can modulate lipid accumulation in adipose tissue. Inhibition of such enzymes has also been reported to influence lipid deposition. We have therefore studied in human adipocytes the lipolytic and lipogenic activities of pharmacological entities designed to interact with amine oxidases highly expressed in this cell type: the semicarbazide-sensitive amine oxidase (SSAO also known as PrAO or VAP-1) and the monoamine oxidases (MAO). The results showed that SZV-2016 and SZV-2017 behaved as better substrates than benzylamine, releasing hydrogen peroxide once oxidized, and reproduced or even exceeded its insulin-like metabolic effects in fat cells. Additionally, several novel SSAO inhibitors, such as SZV-2007 and SZV-1398, have been evidenced and shown to inhibit benzylamine metabolic actions. Taken as a whole, our findings reinforce the list of molecules that influence the regulation of triacylglycerol assembly/breakdown, at least in vitro in human adipocytes. The novel compounds deserve deeper investigation of their mechanisms of interaction with SSAO or MAO, and constitute potential candidates for therapeutic use in obesity and diabetes.
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Protein Expression of AEBP1, MCM4, and FABP4 Differentiate Osteogenic, Adipogenic, and Mesenchymal Stromal Stem Cells. Int J Mol Sci 2022; 23:ijms23052568. [PMID: 35269711 PMCID: PMC8910760 DOI: 10.3390/ijms23052568] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 02/04/2023] Open
Abstract
Mesenchymal stem cells (MSCs) gain an increasing focus in the field of regenerative medicine due to their differentiation abilities into chondrocytes, adipocytes, and osteoblastic cells. However, it is apparent that the transformation processes are extremely complex and cause cellular heterogeneity. The study aimed to characterize differences between MSCs and cells after adipogenic (AD) or osteoblastic (OB) differentiation at the proteome level. Comparative proteomic profiling was performed using tandem mass spectrometry in data-independent acquisition mode. Proteins were quantified by deep neural networks in library-free mode and correlated to the Molecular Signature Database (MSigDB) hallmark gene set collections for functional annotation. We analyzed 4108 proteins across all samples, which revealed a distinct clustering between MSCs and cell differentiation states. Protein expression profiling identified activation of the Peroxisome proliferator-activated receptors (PPARs) signaling pathway after AD. In addition, two distinct protein marker panels could be defined for osteoblastic and adipocytic cell lineages. Hereby, overexpression of AEBP1 and MCM4 for OB as well as of FABP4 for AD was detected as the most promising molecular markers. Combination of deep neural network and machine-learning algorithms with data-independent mass spectrometry distinguish MSCs and cell lineages after adipogenic or osteoblastic differentiation. We identified specific proteins as the molecular basis for bone formation, which could be used for regenerative medicine in the future.
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High doses of tyramine stimulate glucose transport in human fat cells. J Physiol Biochem 2022; 78:543-556. [DOI: 10.1007/s13105-021-00864-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 12/09/2021] [Indexed: 01/13/2023]
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Fontaine J, Tavernier G, Morin N, Carpéné C. Vanadium-dependent activation of glucose transport in adipocytes by catecholamines is not mediated via adrenoceptor stimulation or monoamine oxidase activity. World J Diabetes 2020; 11:622-643. [PMID: 33384769 PMCID: PMC7754167 DOI: 10.4239/wjd.v11.i12.622] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/12/2020] [Accepted: 10/26/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Benzylamine and methylamine activate glucose uptake in adipocytes. For tyramine, this effect has even been extended to cardiomyocytes. AIM To investigate the effects of catecholamines and other amines on glucose uptake. METHODS A screening compared 25 biogenic amines on 2-deoxyglucose (2-DG) uptake activation in rat adipocytes. Pharmacological approaches and transgenic mouse models were then used to decipher the mode of action of several hits. RESULTS In rat adipocytes, insulin stimulation of 2-DG uptake was reproduced with catecholamines. 100 µmol/L or 1 mmol/L adrenaline, noradrenaline, dopamine and deoxyepinephrine, maximally activated hexose transport only when sodium orthovanadate was added at 100 µmol/L. Such activation was similar to that already reported for benzylamine, methylamine and tyramine, well-recognized substrates of semicarbazide-sensitive amine oxidase (SSAO) and monoamine oxidase (MAO). Several, but not all, tested agonists of β-adrenoreceptors (β-ARs) also activated glucose transport while α-AR agonists were inactive. Lack of blockade by α- and β-AR antagonists indicated that catecholamine-induced 2-DG uptake was not mediated by AR stimulation. Adipocytes from mice lacking β1-, β2- and β3-ARs (triple KO) also responded to millimolar doses of adrenaline or noradrenaline by activating hexose transport in the presence of 100 µmol/L vanadate. The MAO blocker pargyline, and SSAO inhibitors did not block the effects of adrenaline or noradrenaline plus vanadate, which were blunted by antioxidants. CONCLUSION Catecholamines exert unexpected insulin-like actions in adipocytes when combined with vanadium. For limiting insulin resistance by activating glucose consumption at least in fat stores, we propose that catecholamine derivatives combined with vanadium can generate novel complexes that may have low toxicity and promising anti-diabetic properties.
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Affiliation(s)
- Jessica Fontaine
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, INSERM UMR1048, Université Paul Sabatier Toulouse III, Toulouse 31432, France
| | - Geneviève Tavernier
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, INSERM UMR1048, Université Paul Sabatier Toulouse III, Toulouse 31432, France
| | - Nathalie Morin
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, INSERM UMR1048, Université Paul Sabatier Toulouse III, Toulouse 31432, France
- INSERM UMR 1139 Faculté de Pharmacie, Université de Paris, Paris 75006, France
| | - Christian Carpéné
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale, INSERM UMR1048, Université Paul Sabatier Toulouse III, Toulouse 31432, France
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Methylxanthines Inhibit Primary Amine Oxidase and Monoamine Oxidase Activities of Human Adipose Tissue. MEDICINES 2020; 7:medicines7040018. [PMID: 32252407 PMCID: PMC7235778 DOI: 10.3390/medicines7040018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/26/2020] [Accepted: 03/28/2020] [Indexed: 12/13/2022]
Abstract
Background: Methylxanthines including caffeine and theobromine are widely consumed compounds and were recently shown to interact with bovine copper-containing amine oxidase. To the best of our knowledge, no direct demonstration of any interplay between these phytochemicals and human primary amine oxidase (PrAO) has been reported to date. We took advantage of the coexistence of PrAO and monoamine oxidase (MAO) activities in human subcutaneous adipose tissue (hScAT) to test the interaction between several methylxanthines and these enzymes, which are involved in many key pathophysiological processes. Methods: Benzylamine, methylamine, and tyramine were used as substrates for PrAO and MAO in homogenates of subcutaneous adipose depots obtained from overweight women undergoing plastic surgery. Methylxanthines were tested as substrates or inhibitors by fluorimetric determination of hydrogen peroxide, an end-product of amine oxidation. Results: Semicarbazide-sensitive PrAO activity was inhibited by theobromine, caffeine, and isobutylmethylxanthine (IBMX) while theophylline, paraxanthine, and 7-methylxanthine had little effect. Theobromine inhibited PrAO activity by 54% at 2.5 mM. Overall, the relationship between methylxanthine structure and the degree of inhibition was similar to that seen with bovine PrAO, although higher concentrations (mM) were required for inhibition. Theobromine also inhibited oxidation of tyramine by MAO, at the limits of its solubility in a DMSO vehicle. At doses higher than 12 % v/v, DMSO impaired MAO activity. MAO was also inhibited by millimolar doses of IBMX, caffeine and by other methylxanthines to a lesser extent. Conclusions: This preclinical study extrapolates previous findings with bovine PrAO to human tissues. Given that PrAO is a potential target for anti-inflammatory drugs, it indicates that alongside phosphodiesterase inhibition and adenosine receptor antagonism, PrAO and MAO inhibition could contribute to the health benefits of methylxanthines, especially their anti-inflammatory effects.
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Carpéné C, Les F, Mercader J, Gomez-Zorita S, Grolleau JL, Boulet N, Fontaine J, Iglesias-Osma MC, Garcia-Barrado MJ. Opipramol Inhibits Lipolysis in Human Adipocytes without Altering Glucose Uptake and Differently from Antipsychotic and Antidepressant Drugs with Adverse Effects on Body Weight Control. Pharmaceuticals (Basel) 2020; 13:ph13030041. [PMID: 32151075 PMCID: PMC7151722 DOI: 10.3390/ph13030041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 02/27/2020] [Accepted: 03/03/2020] [Indexed: 12/15/2022] Open
Abstract
Treatment with several antipsychotic drugs exhibits a tendency to induce weight gain and diabetic complications. The proposed mechanisms by which the atypical antipsychotic drug olanzapine increases body weight include central dysregulations leading to hyperphagia and direct peripheral impairment of fat cell lipolysis. Several investigations have reproduced in vitro direct actions of antipsychotics on rodent adipocytes, cultured preadipocytes, or human adipose tissue-derived stem cells. However, to our knowledge, no such direct action has been described in human mature adipocytes. The aim of the present study was to compare in human adipocytes the putative direct alterations of lipolysis by antipsychotics (haloperidol, olanzapine, ziprazidone, risperidone), antidepressants (pargyline, phenelzine), or anxiolytics (opipramol). Lipolytic responses to the tested drugs, and to recognized lipolytic (e.g., isoprenaline) or antilipolytic agents (e.g., insulin) were determined, together with glucose transport and amine oxidase activities in abdominal subcutaneous adipocytes from individuals undergoing plastic surgery. None of the tested drugs were lipolytic. Surprisingly, only opipramol exhibited substantial antilipolytic properties in the micromolar to millimolar range. An opipramol antilipolytic effect was evident against isoprenaline-, forskolin-, or atrial natriuretic peptide-stimulated lipolysis. Opipramol did not impair insulin activation of glucose transport but inhibited monoamine oxidase (MAO) activity to the same extent as antidepressants recognized as MAO inhibitors (pargyline, harmine, or phenelzine), whereas antipsychotics were inefficient. Considering its unique properties, opipramol, which is not associated with weight gain in treated patients, is a good candidate for drug repurposing because it limits exaggerated lipolysis, prevents hydrogen peroxide release by amine oxidases in adipocytes, and is thereby of potential use to limit lipotoxicity and oxidative stress, two deleterious complications of diabetes and obesity.
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Affiliation(s)
- Christian Carpéné
- Institute of Metabolic and Cardiovascular Diseases, INSERM, UMR1048, Team 1, 31432 Toulouse, France; (N.B.); (J.F.)
- I2MC, University of Toulouse, UMR1048, Paul Sabatier University, 31432 Toulouse, France
- Correspondence:
| | - Francisco Les
- Department of Pharmacy, Faculty of Health Sciences, Universidad San Jorge, 50830 Villanueva de Gállego Zaragoza, Spain;
- Instituto Agroalimentario de Aragón-IA2, CITA-Universidad de Zaragoza, 50013 Zaragoza, Spain
| | - Josep Mercader
- Department of Fundamental Biology and Health Sciences, University of the Balearic Islands, 07122 Palma, Spain;
- Balearic Islands Health Research Institute (IdISBa), 07120 Palma, Spain
| | - Saioa Gomez-Zorita
- Nutrition and Obesity Group, Department of Nutrition and Food Science, University of the Basque Country (UPV/EHU) and Lucio Lascaray Research Institute, 48940 Vitoria, Spain;
| | | | - Nathalie Boulet
- Institute of Metabolic and Cardiovascular Diseases, INSERM, UMR1048, Team 1, 31432 Toulouse, France; (N.B.); (J.F.)
- I2MC, University of Toulouse, UMR1048, Paul Sabatier University, 31432 Toulouse, France
| | - Jessica Fontaine
- Institute of Metabolic and Cardiovascular Diseases, INSERM, UMR1048, Team 1, 31432 Toulouse, France; (N.B.); (J.F.)
- I2MC, University of Toulouse, UMR1048, Paul Sabatier University, 31432 Toulouse, France
| | - Mari Carmen Iglesias-Osma
- Laboratory of Neuroendocrinology, Institute of Neurosciences of Castilla y León (INCyL), University of Salamanca, 37007 Salamanca, Spain; (M.C.I.-O.); (M.J.G.-B.)
- Laboratory of Neuroendocrinology and Obesity, Institute of Biomedical Research of Salamanca (IBSAL), University of Salamanca, 37007 Salamanca, Spain
- Department of Physiology and Pharmacology, Faculty of Medicine, University of Salamanca, 37007 Salamanca, Spain
| | - Maria José Garcia-Barrado
- Laboratory of Neuroendocrinology, Institute of Neurosciences of Castilla y León (INCyL), University of Salamanca, 37007 Salamanca, Spain; (M.C.I.-O.); (M.J.G.-B.)
- Laboratory of Neuroendocrinology and Obesity, Institute of Biomedical Research of Salamanca (IBSAL), University of Salamanca, 37007 Salamanca, Spain
- Department of Physiology and Pharmacology, Faculty of Medicine, University of Salamanca, 37007 Salamanca, Spain
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Saxton SN, Clark BJ, Withers SB, Eringa EC, Heagerty AM. Mechanistic Links Between Obesity, Diabetes, and Blood Pressure: Role of Perivascular Adipose Tissue. Physiol Rev 2019; 99:1701-1763. [PMID: 31339053 DOI: 10.1152/physrev.00034.2018] [Citation(s) in RCA: 136] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Obesity is increasingly prevalent and is associated with substantial cardiovascular risk. Adipose tissue distribution and morphology play a key role in determining the degree of adverse effects, and a key factor in the disease process appears to be the inflammatory cell population in adipose tissue. Healthy adipose tissue secretes a number of vasoactive adipokines and anti-inflammatory cytokines, and changes to this secretory profile will contribute to pathogenesis in obesity. In this review, we discuss the links between adipokine dysregulation and the development of hypertension and diabetes and explore the potential for manipulating adipose tissue morphology and its immune cell population to improve cardiovascular health in obesity.
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Affiliation(s)
- Sophie N Saxton
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom; School of Environment and Life Sciences, University of Salford, Salford, United Kingdom; and Department of Physiology, VU University Medical Centre, Amsterdam, Netherlands
| | - Ben J Clark
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom; School of Environment and Life Sciences, University of Salford, Salford, United Kingdom; and Department of Physiology, VU University Medical Centre, Amsterdam, Netherlands
| | - Sarah B Withers
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom; School of Environment and Life Sciences, University of Salford, Salford, United Kingdom; and Department of Physiology, VU University Medical Centre, Amsterdam, Netherlands
| | - Etto C Eringa
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom; School of Environment and Life Sciences, University of Salford, Salford, United Kingdom; and Department of Physiology, VU University Medical Centre, Amsterdam, Netherlands
| | - Anthony M Heagerty
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom; School of Environment and Life Sciences, University of Salford, Salford, United Kingdom; and Department of Physiology, VU University Medical Centre, Amsterdam, Netherlands
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Sturza A, Olariu S, Ionică M, Duicu OM, Văduva AO, Boia E, Muntean DM, Popoiu CM. Monoamine oxidase is a source of oxidative stress in obese patients with chronic inflammation 1. Can J Physiol Pharmacol 2019; 97:844-849. [PMID: 31051081 DOI: 10.1139/cjpp-2019-0028] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2023]
Abstract
Obesity is an important preventable risk factor for morbidity and mortality from cardiometabolic disease. Oxidative stress (including in visceral adipose tissue) and chronic low-grade inflammation are the major underlying pathomechanisms. Monoamine oxidase (MAO) has recently emerged as an important source of cardiovascular oxidative stress. The present study was conducted to evaluate the role of MAO as contributor to reactive oxygen species (ROS) production in white adipose tissue and vessels harvested from patients undergoing elective abdominal surgery. To this aim, visceral adipose tissue and mesenteric artery branches were isolated from obese patients with chronic inflammation and used for organ bath, ROS production, quantitative real-time PCR, and immunohistology studies. The human visceral adipose tissue and mesenteric artery branches contain mainly the MAO-A isoform, as shown by the quantitative real-time PCR and immunohistology experiments. A significant upregulation of MAO-A, the impairment in vascular reactivity, and increase in ROS production were found in obese vs. non-obese patients. Incubation of the adipose tissue samples and vascular rings with the MAO-A inhibitor (clorgyline, 30 min) improved vascular reactivity and decreased ROS generation. In conclusion, MAO-A is the predominant isoform in human abdominal adipose and vascular tissues, is overexpressed in the setting of inflammation, and contributes to the endothelial dysfunction.
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Affiliation(s)
- Adrian Sturza
- Department of Functional Sciences - Pathophysiology, University of Medicine and Pharmacy of Timișoara, Timișoara, Romania
- Center for Translational Research and Systems Medicine, University of Medicine and Pharmacy of Timișoara, Timișoara, Romania
| | - Sorin Olariu
- Department of Surgery II - 1st Clinic of Surgery, University of Medicine and Pharmacy of Timișoara, Timișoara, Romania
| | - Mihaela Ionică
- Department of Functional Sciences - Pathophysiology, University of Medicine and Pharmacy of Timișoara, Timișoara, Romania
| | - Oana M Duicu
- Department of Functional Sciences - Pathophysiology, University of Medicine and Pharmacy of Timișoara, Timișoara, Romania
- Center for Translational Research and Systems Medicine, University of Medicine and Pharmacy of Timișoara, Timișoara, Romania
| | - Adrian O Văduva
- Department of Microscopic Morphology - Morphopathology, University of Medicine and Pharmacy of Timișoara, Timișoara, Romania
| | - Eugen Boia
- Department of Pediatry - Pediatric Surgery, "Victor Babeș" University of Medicine and Pharmacy of Timișoara, Timișoara, Romania
| | - Danina M Muntean
- Department of Functional Sciences - Pathophysiology, University of Medicine and Pharmacy of Timișoara, Timișoara, Romania
- Center for Translational Research and Systems Medicine, University of Medicine and Pharmacy of Timișoara, Timișoara, Romania
| | - Călin M Popoiu
- Department of Pediatry - Pediatric Surgery, "Victor Babeș" University of Medicine and Pharmacy of Timișoara, Timișoara, Romania
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Abstract
Perivascular adipose tissue (PVAT) is no longer recognised as simply a structural support for the vasculature, and we now know that PVAT releases vasoactive factors which modulate vascular function. Since the discovery of this function in 1991, PVAT research is rapidly growing and the importance of PVAT function in disease is becoming increasingly clear. Obesity is associated with a plethora of vascular conditions; therefore, the study of adipocytes and their effects on the vasculature is vital. PVAT contains an adrenergic system including nerves, adrenoceptors and transporters. In obesity, the autonomic nervous system is dysfunctional; therefore, sympathetic innervation of PVAT may be the key mechanistic link between increased adiposity and vascular disease. In addition, not all obese people develop vascular disease, but a common feature amongst those that do appears to be the inflammatory cell population in PVAT. This review will discuss what is known about sympathetic innervation of PVAT, and the links between nerve activation and inflammation in obesity. In addition, we will examine the therapeutic potential of exercise in sympathetic stimulation of adipose tissue.
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Affiliation(s)
- Sophie N Saxton
- Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Core Technology Facility (3rd floor), 46 Grafton Street, M13 9NT, Manchester, UK.
| | - Sarah B Withers
- Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Core Technology Facility (3rd floor), 46 Grafton Street, M13 9NT, Manchester, UK
- School of Environment and Life Sciences, University of Salford, Manchester, UK
| | - Anthony M Heagerty
- Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Core Technology Facility (3rd floor), 46 Grafton Street, M13 9NT, Manchester, UK
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12
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Carpéné C, Boulet N, Chaplin A, Mercader J. Past, Present and Future Anti-Obesity Effects of Flavin-Containing and/or Copper-Containing Amine Oxidase Inhibitors. MEDICINES (BASEL, SWITZERLAND) 2019; 6:E9. [PMID: 30650583 PMCID: PMC6473341 DOI: 10.3390/medicines6010009] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 01/10/2019] [Accepted: 01/11/2019] [Indexed: 12/12/2022]
Abstract
Background: Two classes of amine oxidases are found in mammals: those with a flavin adenine dinucleotide as a cofactor, such as monoamine oxidases (MAO) and lysine-specific demethylases (LSD), and those with copper as a cofactor, including copper-containing amine oxidases (AOC) and lysyl oxidases (LOX). All are expressed in adipose tissue, including a semicarbazide-sensitive amine oxidase/vascular adhesion protein-1 (SSAO/VAP-1) strongly present on the adipocyte surface. Methods: Previously, irreversible MAO inhibitors have been reported to limit food intake and/or fat extension in rodents; however, their use for the treatment of depressed patients has not revealed a clear anti-obesity action. Semicarbazide and other molecules inhibiting SSAO/VAP-1 also reduce adiposity in obese rodents. Results: Recently, a LOX inhibitor and a subtype-selective MAO inhibitor have been shown to limit fattening in high-fat diet-fed rats. Phenelzine, which inhibits MAO and AOC, limits adipogenesis in cultured preadipocytes and impairs lipogenesis in mature adipocytes. When tested in rats or mice, phenelzine reduces food intake and/or fat accumulation without cardiac adverse effects. Novel amine oxidase inhibitors have been recently characterized in a quest for promising anti-inflammatory or anti-cancer approaches; however, their capacity to mitigate obesity has not been studied so far. Conclusions: The present review of the diverse effects of amine oxidase inhibitors impairing adipocyte differentiation or limiting excessive fat accumulation indicates that further studies are needed to reveal their potential anti-obesity properties.
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Affiliation(s)
- Christian Carpéné
- Institute of Metabolic and Cardiovascular Diseases, INSERM, UMR1048, Team 1, 31432 Toulouse, France.
- I2MC, University of Toulouse, UMR1048, Paul Sabatier University, 31432 Toulouse Cedex 4, France.
| | - Nathalie Boulet
- Institute of Metabolic and Cardiovascular Diseases, INSERM, UMR1048, Team 1, 31432 Toulouse, France.
- I2MC, University of Toulouse, UMR1048, Paul Sabatier University, 31432 Toulouse Cedex 4, France.
| | - Alice Chaplin
- Cardiovascular Research Institute, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Josep Mercader
- Department of Fundamental Biology and Health Sciences, University of the Balearic Islands, 07122 Palma, Spain.
- Balearic Islands Health Research Institute (IdISBa), 07122 Palma, Spain.
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13
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Song W, Luo Q, Zhang Y, Zhou L, Liu Y, Ma Z, Guo J, Huang Y, Cheng L, Meng Z, Li Z, Zhang B, Li S, Yee SW, Fan H, Li P, Giacomini KM, Chen L. Organic cation transporter 3 (Oct3) is a distinct catecholamines clearance route in adipocytes mediating the beiging of white adipose tissue. PLoS Biol 2019; 17:e2006571. [PMID: 30653498 PMCID: PMC6336244 DOI: 10.1371/journal.pbio.2006571] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 12/13/2018] [Indexed: 02/05/2023] Open
Abstract
Beiging of white adipose tissue (WAT) is a particularly appealing target for therapeutics in the treatment of metabolic diseases through norepinephrine (NE)-mediated signaling pathways. Although previous studies report NE clearance mechanisms via SLC6A2 on sympathetic neurons or proinflammatory macrophages in adipose tissues (ATs), the low catecholamine clearance capacity of SLC6A2 may limit the cleaning efficiency. Here, we report that mouse organic cation transporter 3 (Oct3; Slc22a3) is highly expressed in WAT and displays the greatest uptake rate of NE as a selective non-neural route of NE clearance in white adipocytes, which differs from other known routes such as adjacent neurons or macrophages. We further show that adipocytes express high levels of NE degradation enzymes Maoa, Maob, and Comt, providing the molecular basis on NE clearance by adipocytes together with its reuptake transporter Oct3. Under NE administration, ablation of Oct3 induces higher body temperature, thermogenesis, and lipolysis compared with littermate controls. After prolonged cold challenge, inguinal WAT (ingWAT) in adipose-specific Oct3-deficient mice shows much stronger browning characteristics and significantly elevated expression of thermogenic and mitochondrial biogenesis genes than in littermate controls, and this response involves enhanced β-adrenergic receptor (β-AR)/protein kinase A (PKA)/cyclic adenosine monophosphate (cAMP)-responsive element binding protein (Creb) pathway activation. Glycolytic genes are reprogrammed to significantly higher levels to compensate for the loss of ATP production in adipose-specific Oct3 knockout (KO) mice, indicating the fundamental role of glucose metabolism during beiging. Inhibition of β-AR largely abolishes the higher lipolytic and thermogenic activities in Oct3-deficient ingWAT, indicating the NE overload in the vicinity of adipocytes in Oct3 KO adipocytes. Of note, reduced functional alleles in human OCT3 are also identified to be associated with increased basal metabolic rate (BMR). Collectively, our results demonstrate that Oct3 governs β-AR activity as a NE recycling transporter in white adipocytes, offering potential therapeutic applications for metabolic disorders.
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Affiliation(s)
- Wenxin Song
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Qi Luo
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
- Department of Bioengineering and Therapeutic Sciences, Schools of Pharmacy and Medicine, University of California, San Francisco, California
- Institute for Human Genetics, University of California, San Francisco, California
| | - Yuping Zhang
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Linkang Zhou
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ye Liu
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Zhilong Ma
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Jianan Guo
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Yuedong Huang
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Lili Cheng
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Ziyi Meng
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Zicheng Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Bin Zhang
- Institute of Immunology, School of Medicine, Tsinghua University, Beijing, China
| | - Siqi Li
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Sook Wah Yee
- Department of Bioengineering and Therapeutic Sciences, Schools of Pharmacy and Medicine, University of California, San Francisco, California
- Institute for Human Genetics, University of California, San Francisco, California
| | - Hao Fan
- Bioinformatics Institute, Agency for Science, Technology and Research, Singapore; Department of Biological Sciences, National University of Singapore, Singapore; Centre for Computational Biology, DUKE-NUS Medical School, Singapore
| | - Peng Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Kathleen M Giacomini
- Department of Bioengineering and Therapeutic Sciences, Schools of Pharmacy and Medicine, University of California, San Francisco, California
- Institute for Human Genetics, University of California, San Francisco, California
| | - Ligong Chen
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
- Collaborative Innovation Center for Biotherapy, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, China
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14
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Nagy CT, Koncsos G, Varga ZV, Baranyai T, Tuza S, Kassai F, Ernyey AJ, Gyertyán I, Király K, Oláh A, Radovits T, Merkely B, Bukosza N, Szénási G, Hamar P, Mathé D, Szigeti K, Pelyhe C, Jelemenský M, Onódi Z, Helyes Z, Schulz R, Giricz Z, Ferdinandy P. Selegiline reduces adiposity induced by high-fat, high-sucrose diet in male rats. Br J Pharmacol 2018; 175:3713-3726. [PMID: 29971762 DOI: 10.1111/bph.14437] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 06/22/2018] [Accepted: 06/25/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Incidence and severity of obesity are increasing worldwide, however, efficient and safe pharmacological treatments are not yet available. Certain MAO inhibitors reduce body weight, although their effects on metabolic parameters have not been investigated. Here, we have assessed effects of a widely used, selective MAO-B inhibitor, selegiline, on metabolic parameters in a rat model of diet-induced obesity. EXPERIMENTAL APPROACH Male Long-Evans rats were given control (CON) or a high-fat (20%), high-sucrose (15%) diet (HFS) for 25 weeks. From week 16, animals were injected s.c. with 0.25 mg·kg-1 selegiline (CON + S and HFS + S) or vehicle (CON, HFS) once daily. Whole body, subcutaneous and visceral fat was measured by CT, and glucose and insulin tolerance were tested. Expression of glucose transporters and chemokines was assessed by quantitative RT-PCR. KEY RESULTS Selegiline decreased whole body fat, subcutaneous- and visceral adiposity, measured by CT and epididymal fat weight in the HFS group, compared with HFS placebo animals, without influencing body weight. Oral glucose tolerance and insulin tolerance tests showed impaired glucose homeostasis in HFS and HFS + S groups, although insulin levels in plasma and pancreas were unchanged. HFS induced expression of Srebp-1c, Glut1 and Ccl3 in adipose tissue, which were alleviated by selegiline. CONCLUSIONS AND IMPLICATIONS Selegiline reduced adiposity, changes in adipose tissue energy metabolism and adipose inflammation induced by HFS diet without affecting the increased body weight, impairment of glucose homeostasis, or behaviour. These results suggest that selegiline could mitigate harmful effects of visceral adiposity.
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Affiliation(s)
- Csilla Terézia Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Gábor Koncsos
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Zoltán V Varga
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Tamás Baranyai
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Sebestyén Tuza
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Ferenc Kassai
- MTA-SE NAP B Cognitive Translational Behavioural Pharmacology Group, Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary.,Institute of Cognitive Neuroscience and Psychology, Research Center for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Aliz Judit Ernyey
- MTA-SE NAP B Cognitive Translational Behavioural Pharmacology Group, Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary.,Institute of Cognitive Neuroscience and Psychology, Research Center for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - István Gyertyán
- MTA-SE NAP B Cognitive Translational Behavioural Pharmacology Group, Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary.,Institute of Cognitive Neuroscience and Psychology, Research Center for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Kornél Király
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Attila Oláh
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Tamás Radovits
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Béla Merkely
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Nóra Bukosza
- Institute of Pathophysiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Gábor Szénási
- Institute of Pathophysiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Péter Hamar
- Institute of Pathophysiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary.,Clinical Experimental Research Institute, Faculty of Medicine, Semmelweis University, Budapest, Hungary.,Translational Medicine Institute, Faculty of Medicine, Pécs University, Pécs, Hungary
| | - Domokos Mathé
- Department of Biophysics and Radiation Biology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Krisztián Szigeti
- Department of Biophysics and Radiation Biology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Csilla Pelyhe
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Marek Jelemenský
- Institute for Heart Research, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Zsófia Onódi
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Zsuzsanna Helyes
- Department of Pharmacology and Pharmacotherapy, Medical School and Szentágothai Research Centre, University of Pécs, Pécs, Hungary
| | - Rainer Schulz
- Institute of Physiology, Justus-Liebig University Giessen, Germany
| | - Zoltán Giricz
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary.,Pharmahungary Group, Szeged, Hungary
| | - Péter Ferdinandy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Budapest, Hungary.,Pharmahungary Group, Szeged, Hungary
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15
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Mechanisms of the antilipolytic response of human adipocytes to tyramine, a trace amine present in food. J Physiol Biochem 2018; 74:623-633. [PMID: 30039351 DOI: 10.1007/s13105-018-0643-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 07/09/2018] [Indexed: 12/12/2022]
Abstract
Tyramine is found in foodstuffs, the richest being cheeses, sausages, and wines. Tyramine has been recognized to release catecholamines from nerve endings and to trigger hypertensive reaction. Thereby, tyramine-free diet is recommended for depressed patients treated with irreversible inhibitors of monoamine oxidases (MAO) to limit the risk of hypertension. Tyramine is a substrate of amine oxidases and also an agonist at trace amine-associated receptors. Our aim was to characterize the dose-dependent effects of tyramine on human adipocyte metabolic functions. Lipolytic activity was determined in adipocytes from human subcutaneous abdominal adipose tissue. Glycerol release was increased by a fourfold factor with classical lipolytic agents (1 μM isoprenaline, 1 mM isobutylmethylxanthine) while the amine was ineffective from 0.01 to 100 μM and hardly stimulatory at 1 mM. Tyramine exhibited a partial antilipolytic effect at 100 μM and 1 mM, which was similar to that of insulin but weaker than that obtained with agonists at purinergic A1 receptors, α2-adrenoceptors, or nicotinic acid receptors. Gi-protein blockade by Pertussis toxin abolished all these antilipolytic responses save that of tyramine. Indeed, tyramine antilipolytic effect was impaired by MAO-A inhibition. Tyramine inhibited protein tyrosine phosphatase activities in a manner sensitive to ascorbic acid and amine oxidase inhibitors. Thus, millimolar tyramine restrained lipolysis via the hydrogen peroxide it generates when oxidized by MAO. Since tyramine plasma levels have been reported to reach 0.2 μM after ingestion of 200 mg tyramine in healthy individuals, the direct effects we observed in vitro on adipocytes could be nutritionally relevant only when the MAO-dependent hepato-intestinal detoxifying system is overpassed.
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16
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Carpéné C, Pejenaute H, Del Moral R, Boulet N, Hijona E, Andrade F, Villanueva-Millán MJ, Aguirre L, Arbones-Mainar JM. The Dietary Antioxidant Piceatannol Inhibits Adipogenesis of Human Adipose Mesenchymal Stem Cells and Limits Glucose Transport and Lipogenic Activities in Adipocytes. Int J Mol Sci 2018; 19:ijms19072081. [PMID: 30018277 PMCID: PMC6073844 DOI: 10.3390/ijms19072081] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 12/20/2022] Open
Abstract
Phenolic compounds are among the most investigated herbal remedies, as is especially the case for resveratrol. Many reports have shown its anti-aging properties and the ability to reduce obesity and diabetes induced by high-fat diet in mice. However, such beneficial effects hardly translate from animal models to humans. The scientific community has therefore tested whether other plant phenolic compounds may surpass the effects of resveratrol. In this regard, it has been reported that piceatannol reproduces in rodents the anti-obesity actions of its parent polyphenol. However, the capacity of piceatannol to inhibit adipocyte differentiation in humans has not been characterized so far. Here, we investigated whether piceatannol was antiadipogenic and antilipogenic in human preadipocytes. Human mesenchymal stem cells (hMSC), isolated from adipose tissues of lean and obese individuals, were differentiated into mature adipocytes with or without piceatannol, and their functions were explored. Fifty µM of piceatannol deeply limited synthesis/accumulation of lipids in both murine and hMSC-derived adipocytes. Interestingly, this phenomenon occurred irrespective of being added at the earlier or later stages of adipocyte differentiation. Moreover, piceatannol lowered glucose transport into adipocytes and decreased the expression of key elements of the lipogenic pathway (PPARγ, FAS, and GLUT4). Thus, the confirmation of the antiadipogenic properties of piceatanol in vitro warrants the realization of clinical studies for the application of this compound in the treatment of the metabolic complications associated with obesity.
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Affiliation(s)
- Christian Carpéné
- INSERM U1048, Institute of Metabolic and Cardiovascular Diseases (I2MC), Paul Sabatier University, 31059 Toulouse, France.
| | - Héctor Pejenaute
- Adipocyte and Fat Biology Laboratory (AdipoFat), Unidad de Investigación Traslacional, Instituto Aragonés de Ciencias de la Salud (IACS), Instituto de Investigación Sanitaria (IIS) Aragon, 50009 Zaragoza, Spain.
| | - Raquel Del Moral
- Adipocyte and Fat Biology Laboratory (AdipoFat), Unidad de Investigación Traslacional, Instituto Aragonés de Ciencias de la Salud (IACS), Instituto de Investigación Sanitaria (IIS) Aragon, 50009 Zaragoza, Spain.
| | - Nathalie Boulet
- INSERM U1048, Institute of Metabolic and Cardiovascular Diseases (I2MC), Paul Sabatier University, 31059 Toulouse, France.
| | - Elizabeth Hijona
- Department of Gastroenterology, University of Basque Country (UPV/EHU), Biodonostia Research Institute, 20014 San Sebastián, Spain.
| | - Fernando Andrade
- Division of Metabolism, Cruces University Hospital and BioCruces Health Research Institute, Plaza de Cruces s/n, 48903 Barakaldo, Spain.
| | - Maria Jesùs Villanueva-Millán
- HIV and Associated Metabolic Alterations Unit, Infectious Diseases Department, Center for Biomedical Research of La Rioja (CIBIR), 26006 Logroño, Spain.
| | - Leixuri Aguirre
- Nutrition and Obesity Group, Department of Nutrition and Food Science, Faculty of Pharmacy and Lucio Lascaray Research Center, University of the Basque Country (UPV/EHU), 01006 Vitoria, Spain.
- CIBEROBN Physiopathology of Obesity and Nutrition, Institute of Health Carlos III (ISCIII), 28029 Madrid, Spain.
| | - José Miguel Arbones-Mainar
- Adipocyte and Fat Biology Laboratory (AdipoFat), Unidad de Investigación Traslacional, Instituto Aragonés de Ciencias de la Salud (IACS), Instituto de Investigación Sanitaria (IIS) Aragon, 50009 Zaragoza, Spain.
- CIBEROBN Physiopathology of Obesity and Nutrition, Institute of Health Carlos III (ISCIII), 28029 Madrid, Spain.
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17
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Pomegranate juice and its main polyphenols exhibit direct effects on amine oxidases from human adipose tissue and inhibit lipid metabolism in adipocytes. J Funct Foods 2017. [DOI: 10.1016/j.jff.2017.04.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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18
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Breining P, Pedersen SB, Pikelis A, Rolighed L, Sundelin EIO, Jessen N, Richelsen B. High expression of organic cation transporter 3 in human BAT-like adipocytes. Implications for extraneuronal norepinephrine uptake. Mol Cell Endocrinol 2017; 443:15-22. [PMID: 28034777 DOI: 10.1016/j.mce.2016.12.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 12/21/2016] [Accepted: 12/22/2016] [Indexed: 01/11/2023]
Abstract
Brown adipose tissue (BAT) is activated by extracellular norepinephrine (NE) released by the sympathetic nervous system. The extracellular concentration of NE is additionally regulated by the disappearance/degradation of NE. Recent studies have introduced the organic cation transporter 3 (OCT3) as a possible contributor in the regulation of NE in adipose tissue. In the present study we set out to investigate the presence of OCT3 in human neck adipose tissue (AT), which is the primary localization of BAT in humans. Moreover, we wanted to assess the possible function and correlation of the transporter with known markers of thermogenic function, e.g. UCP1. When examining neck AT biopsies from 57 individuals we found that OCT3 was expressed at 2.5 ± 0.16 fold higher level in the deep-neck AT compared with subcutaneous AT. UCP1 was found extensively expressed in the deep-neck AT depot and the correlation between UCP1 and OCT3 within the deep-neck AT was found highly significant (r2 = 0.4012, P-value < 0.0001). Lastly, we were able to reduce NE uptake in isolated brown adipocytes in an in vitro culture by adding corticosterone which is a known OCT3-blocker. In conclusion, we found that OCT3 may be a regulator of the concentration of NE in AT and by this mechanism a possible regulator of BAT function and a potential target for pharmacological intervention.
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Affiliation(s)
- Peter Breining
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, 8000 Aarhus C, Denmark.
| | - Steen Bønløkke Pedersen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, 8000 Aarhus C, Denmark.
| | - Arunas Pikelis
- Department of Otorhinolaryngology, Aarhus University Hospital, 8000 Aarhus C, Denmark.
| | - Lars Rolighed
- Department of Otorhinolaryngology, Aarhus University Hospital, 8000 Aarhus C, Denmark; Department of Surgery P, Aarhus University Hospital, 8000 Aarhus C, Denmark.
| | | | - Niels Jessen
- Research Laboratory for Biochemical Pathology, Aarhus University Hospital, 8000 Aarhus C, Denmark; Department of Clinical Pharmacology, Aarhus University Hospital, 8000 Aarhus C, Denmark.
| | - Bjørn Richelsen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, 8000 Aarhus C, Denmark.
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19
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Ayala-Lopez N, Thompson JM, Watts SW. Perivascular Adipose Tissue's Impact on Norepinephrine-Induced Contraction of Mesenteric Resistance Arteries. Front Physiol 2017; 8:37. [PMID: 28228728 PMCID: PMC5296360 DOI: 10.3389/fphys.2017.00037] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/13/2017] [Indexed: 01/22/2023] Open
Abstract
Background: Perivascular adipose tissue (PVAT) can decrease vascular contraction to NE. We tested the hypothesis that metabolism and/or uptake of vasoactive amines by mesenteric PVAT (MPVAT) could affect NE-induced contraction of the mesenteric resistance arteries. Methods: Mesenteric resistance vessels (MRV) and MPVAT from male Sprague-Dawley rats were used. RT-PCR and Western blots were performed to detect amine metabolizing enzymes. The Amplex® Red Assay was used to quantify oxidase activity by detecting the oxidase reaction product H2O2 and the contribution of PVAT on the mesenteric arteries' contraction to NE was measured by myography. Results: Semicarbazide sensitive amine oxidase (SSAO) and monoamine oxidase A (MAO-A) were detected in MRV and MPVAT by Western blot. Addition of the amine oxidase substrates tyramine or benzylamine (1 mM) resulted in higher amine oxidase activity in the MRV, MPVAT, MPVAT's adipocyte fraction (AF), and the stromal vascular fraction (SVF). Inhibiting SSAO with semicarbazide (1 mM) decreased amine oxidase activity in the MPVAT and AF. Benzylamine-driven, but not tyramine-driven, oxidase activity in the MRV was reduced by semicarbazide. By contrast, no reduction in oxidase activity in all sample types was observed with use of the monoamine oxidase inhibitors clorgyline (1 μM) or pargyline (1 μM). Inhibition of MAO-A/B or SSAO individually did not alter contraction to NE. However, inhibition of both MAO and SSAO increased the potency of NE at mesenteric arteries with PVAT. Addition of MAO and SSAO inhibitors along with the H2O2 scavenger catalase reduced PVAT's anti-contractile effect to NE. Inhibition of the norepinephrine transporter (NET) with nisoxetine also reduced PVAT's anti-contractile effect to NE. Conclusions: PVAT's uptake and metabolism of NE may contribute to the anti-contractile effect of PVAT. MPVAT and adipocytes within MPVAT are a source of SSAO.
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Affiliation(s)
- Nadia Ayala-Lopez
- Department of Pharmacology and Toxicology, Michigan State UniversityEast Lansing, MI, USA
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20
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Ayala-Lopez N, Watts SW. New actions of an old friend: perivascular adipose tissue's adrenergic mechanisms. Br J Pharmacol 2016; 174:3454-3465. [PMID: 27813085 DOI: 10.1111/bph.13663] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 10/03/2016] [Accepted: 10/21/2016] [Indexed: 12/17/2022] Open
Abstract
The revolutionary discovery in 1991 by Soltis and Cassis that perivascular adipose tissue (PVAT) has an anti-contractile effect changed how we think about the vasculature. Most experiments on vascular pharmacology begin by removing the fat surrounding vessels. Thus, PVAT was thought to have a minor role in vascular function and its presence was just for structural support. The need to rethink PVAT's role was precipitated by observations that obesity carries a high cardiovascular risk and PVAT dysfunction is associated with obesity. PVAT is a vascular-adipose organ that has intimate connections with the nervous and immune system. A complex world of physiology resides in PVAT, including the presence of an 'adrenergic system' that is able to release, take up and metabolize noradrenaline. Adipocytes, stromal vascular cells and nerves within PVAT contain components that make up this adrenergic system. Some of the great strides in PVAT research came from studying adipose tissue as a whole. Adipose tissue has many roles and participates in regulating energy balance, energy stores, inflammation and thermoregulation. However, PVAT is dissimilar from non-PVAT adipose tissues. PVAT is intimately connected with the vasculature, which is what makes its role in body homeostasis unique. The adrenergic system within PVAT may be an integral link connecting the effects of obesity with the vascular dysfunction observed in obesity-associated hypertension, a condition in which the sympathetic nervous system has a significant role. This review will explore what is known about the adrenergic system in adipose tissue and PVAT, plus the translational importance of these findings. LINKED ARTICLES This article is part of a themed section on Molecular Mechanisms Regulating Perivascular Adipose Tissue - Potential Pharmacological Targets? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.20/issuetoc.
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Affiliation(s)
- Nadia Ayala-Lopez
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
| | - Stephanie W Watts
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA
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21
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Les F, Deleruyelle S, Cassagnes LE, Boutin JA, Balogh B, Arbones-Mainar JM, Biron S, Marceau P, Richard D, Nepveu F, Mauriège P, Carpéné C. Piceatannol and resveratrol share inhibitory effects on hydrogen peroxide release, monoamine oxidase and lipogenic activities in adipose tissue, but differ in their antilipolytic properties. Chem Biol Interact 2016; 258:115-25. [PMID: 27475863 DOI: 10.1016/j.cbi.2016.07.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/05/2016] [Accepted: 07/11/2016] [Indexed: 02/06/2023]
Abstract
Piceatannol is a hydroxylated derivative of resveratrol. While both dietary polyphenols coexist in edible plants and fruits, and share equivalent concentrations in several wines, the influence of piceatannol on adiposity has been less studied than that of resveratrol. Though resveratrol is now recognized to limit fat deposition in various obesity models, the benefit of its dietary supplementation remains under debate regarding human obesity treatment or prevention. The research for more potent resveratrol analogs is therefore still undergoing. This prompted us to compare various effects of piceatannol and resveratrol directly on human adipose tissue (hAT). Hydrogen peroxide release was measured by Amplex Red-based fluorescence in subcutaneous hAT samples from obese patients. Interactions of stilbenes with human amine oxidases and quinone reductase were assessed by radiometric methods, computational docking and electron paramagnetic resonance. Influences on lipogenic and lipolytic activities were compared in mouse adipocytes. Resveratrol and piceatannol inhibited monoamine oxidase (MAO) with respective IC50 of 18.5 and 133.7 μM, but not semicarbazide-sensitive amine oxidase (SSAO) in hAT. For both stilbenes, the docking scores were better for MAO than for SSAO. Piceatannol and resveratrol similarly hampered hydrogen peroxide detection in assays with and without hAT, while they shared pro-oxidant activities when incubated with purified quinone reductase. They exhibited similar dose-dependent inhibition of adipocyte lipogenic activity. Only piceatannol inhibited basal and stimulated lipolysis when incubated at a dose ≥100 μM. Thus, piceatannol exerted on fat cells dose-dependent effects similar to those of resveratrol, except for a stronger antilipolytic action. In this regard, piceatannol should be useful in limiting the lipotoxicity related to obesity when ingested or administered alone - or might hamper the fat mobilization induced by resveratrol when simultaneously administered with it.
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Affiliation(s)
- Francisco Les
- Instit. Maladies Métaboliques et Cardiovasculaires, I2MC, INSERM U1048, Instit. National de la Santé et de la Recherche Médicale, Toulouse, France; Dpt. of Pharmacy, Fac. Health Sciences, Univ. San Jorge, Zaragoza, Spain
| | - Simon Deleruyelle
- Instit. Maladies Métaboliques et Cardiovasculaires, I2MC, INSERM U1048, Instit. National de la Santé et de la Recherche Médicale, Toulouse, France; I2MC, CHU Rangueil, Univ. Paul Sabatier, Toulouse, France
| | | | - Jean A Boutin
- Dpt. de Biotechnologie, Chimie & Biologie, Instit. de Recherches Servier, Croissy sur Seine, France
| | - Balázs Balogh
- Dpt. of Organic Chemistry, Semmelweiss Univ., Budapest, Hungary
| | | | - Simon Biron
- Dpt. of Surgery, Fac. Medicine, Laval Univ., CRIUCPQ, Québec, Canada
| | - Picard Marceau
- Dpt. of Surgery, Fac. Medicine, Laval Univ., CRIUCPQ, Québec, Canada
| | - Denis Richard
- Dpt. of Physiology, Fac. Medicine, Laval Univ., CRIUCPQ, Québec, Canada
| | - Françoise Nepveu
- Univ. of Toulouse, PHARMA-DEV, Univ. Paul Sabatier & IRD, Toulouse, France
| | - Pascale Mauriège
- Dpt. of Kinesiology, Fac. Medicine, Laval Univ., CRIUCPQ, Québec, Canada
| | - Christian Carpéné
- Instit. Maladies Métaboliques et Cardiovasculaires, I2MC, INSERM U1048, Instit. National de la Santé et de la Recherche Médicale, Toulouse, France; I2MC, CHU Rangueil, Univ. Paul Sabatier, Toulouse, France.
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Walton RG, Zhu X, Tian L, Heywood EB, Liu J, Hill HS, Liu J, Bruemmer D, Yang Q, Fu Y, Garvey WT. AP2-NR4A3 transgenic mice display reduced serum epinephrine because of increased catecholamine catabolism in adipose tissue. Am J Physiol Endocrinol Metab 2016; 311:E69-81. [PMID: 27166283 PMCID: PMC4967153 DOI: 10.1152/ajpendo.00330.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 05/03/2016] [Indexed: 01/25/2023]
Abstract
The NR4A orphan nuclear receptors function as early response genes to numerous stimuli. Our laboratory has previously demonstrated that overexpression of NR4A3 (NOR-1, MINOR) in 3T3-L1 adipocytes enhances insulin-stimulated glucose uptake. To assess the in vivo effect of NR4A3 on adipocytes, we generated transgenic mice with NR4A3 overexpression driven by the adipocyte fatty acid-binding protein (AP2) promoter (AP2-NR4A3 mice). We hypothesized that AP2-NR4A3 mice would display enhanced glucose tolerance and insulin sensitivity. However, AP2-NR4A3 mice exhibit metabolic impairment, including increased fasting glucose and insulin, impaired glucose tolerance, insulin resistance, decreased serum free fatty acids, and increased low-density lipoprotein-cholesterol. AP2-NR4A3 mice also display a significant reduction in serum epinephrine due to increased expression of catecholamine-catabolizing enzymes in adipose tissue, including monoamine oxidase-A. Furthermore, enhanced expression of monoamine oxidase-A is due to direct transcriptional activation by NR4A3. Finally, AP2-NR4A3 mice display cardiac and behavioral alterations consistent with chronically low circulating epinephrine levels. In conclusion, overexpression of NR4A3 in adipocytes produces a complex phenotype characterized by impaired glucose metabolism and low serum catecholamines due to enhanced degradation by adipose tissue.
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Affiliation(s)
- R Grace Walton
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama;
| | - Xiaolin Zhu
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama
| | - Ling Tian
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama
| | - Elizabeth B Heywood
- Saha Cardiovascular Research Center and Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, Kentucky
| | - Jian Liu
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama
| | - Helliner S Hill
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jiarong Liu
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Dennis Bruemmer
- Saha Cardiovascular Research Center and Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, Kentucky
| | - Qinglin Yang
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama
| | - Yuchang Fu
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama
| | - W Timothy Garvey
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama; Birmingham Veterans Affairs Medical Center, Birmingham, Alabama
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Dietary Phenolic Compounds Interfere with the Fate of Hydrogen Peroxide in Human Adipose Tissue but Do Not Directly Inhibit Primary Amine Oxidase Activity. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:2427618. [PMID: 26881018 PMCID: PMC4736399 DOI: 10.1155/2016/2427618] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/12/2015] [Indexed: 12/31/2022]
Abstract
Resveratrol has been reported to inhibit monoamine oxidases (MAO). Many substrates or inhibitors of neuronal MAO interact also with other amine oxidases (AO) in peripheral organs, such as semicarbazide-sensitive AO (SSAO), known as primary amine oxidase, absent in neurones, but abundant in adipocytes. We asked whether phenolic compounds (resveratrol, pterostilbene, quercetin, and caffeic acid) behave as MAO and SSAO inhibitors. AO activity was determined in human adipose tissue. Computational docking and glucose uptake assays were performed in 3D models of human AO proteins and in adipocytes, respectively. Phenolic compounds fully inhibited the fluorescent detection of H2O2 generated during MAO and SSAO activation by tyramine and benzylamine. They also quenched H2O2-induced fluorescence in absence of biological material and were unable to abolish the oxidation of radiolabelled tyramine and benzylamine. Thus, phenolic compounds hampered H2O2 detection but did not block AO activity. Only resveratrol and quercetin partially impaired MAO-dependent [(14)C]-tyramine oxidation and behaved as MAO inhibitors. Phenolic compounds counteracted the H2O2-dependent benzylamine-stimulated glucose transport. This indicates that various phenolic compounds block downstream effects of H2O2 produced by biogenic or exogenous amine oxidation without directly inhibiting AO. Phenolic compounds remain of interest regarding their capacity to limit oxidative stress rather than inhibiting AO.
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Carpéné C, Galitzky J, Sébastien Saulnier-Blache J. Short-term and rapid effects of lysophosphatidic acid on human adipose cell lipolytic and glucose uptake activities. AIMS MOLECULAR SCIENCE 2016. [DOI: 10.3934/molsci.2016.2.222] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Ayala-Lopez N, Jackson WF, Burnett R, Wilson JN, Thompson JM, Watts SW. Organic cation transporter 3 contributes to norepinephrine uptake into perivascular adipose tissue. Am J Physiol Heart Circ Physiol 2015; 309:H1904-14. [PMID: 26432838 PMCID: PMC4698381 DOI: 10.1152/ajpheart.00308.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/30/2015] [Indexed: 12/23/2022]
Abstract
Perivascular adipose tissue (PVAT) reduces vasoconstriction to norepinephrine (NE). A mechanism by which PVAT could function to reduce vascular contraction is by decreasing the amount of NE to which the vessel is exposed. PVATs from male Sprague-Dawley rats were used to test the hypothesis that PVAT has a NE uptake mechanism. NE was detected by HPLC in mesenteric PVAT and isolated adipocytes. Uptake of NE (10 μM) in mesenteric PVAT was reduced by the NE transporter (NET) inhibitor nisoxetine (1 μM, 73.68 ± 7.62%, all values reported as percentages of vehicle), the 5-hydroxytryptamine transporter (SERT) inhibitor citalopram (100 nM) with the organic cation transporter 3 (OCT3) inhibitor corticosterone (100 μM, 56.18 ± 5.21%), and the NET inhibitor desipramine (10 μM) with corticosterone (100 μM, 61.18 ± 6.82%). Aortic PVAT NE uptake was reduced by corticosterone (100 μM, 53.01 ± 10.96%). Confocal imaging of mesenteric PVAT stained with 4-[4-(dimethylamino)-styrl]-N-methylpyridinium iodide (ASP(+)), a fluorescent substrate of cationic transporters, detected ASP(+) uptake into adipocytes. ASP(+) (2 μM) uptake was reduced by citalopram (100 nM, 66.68 ± 6.43%), corticosterone (100 μM, 43.49 ± 10.17%), nisoxetine (100 nM, 84.12 ± 4.24%), citalopram with corticosterone (100 nM and 100 μM, respectively, 35.75 ± 4.21%), and desipramine with corticosterone (10 and 100 μM, respectively, 50.47 ± 5.78%). NET protein was not detected in mesenteric PVAT adipocytes. Expression of Slc22a3 (OCT3 gene) mRNA and protein in PVAT adipocytes was detected by RT-PCR and immunocytochemistry, respectively. These end points support the presence of a transporter-mediated NE uptake system within PVAT with a potential mediator being OCT3.
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Affiliation(s)
- Nadia Ayala-Lopez
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Robert Burnett
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - James N Wilson
- Department of Chemistry, University of Miami, Coral Gables, Florida
| | - Janice M Thompson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Stephanie W Watts
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
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Carpéné C, Bizou M, Tréguer K, Hasnaoui M, Grès S. Glitazones inhibit human monoamine oxidase but their anti-inflammatory actions are not mediated by VAP-1/semicarbazide-sensitive amine oxidase inhibition. J Physiol Biochem 2015; 71:487-96. [PMID: 25572340 DOI: 10.1007/s13105-014-0379-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 12/26/2014] [Indexed: 10/24/2022]
Abstract
Glitazones are peroxisome proliferator-activated receptor gamma (PPARγ) agonists widely used as antidiabetic drugs also known as thiazolidinediones. Most of them exert other effects such as anti-inflammatory actions via mechanisms supposed to be independent from PPARγ activation (e.g., decreased plasma monocyte chemoattractant protein-1 (MCP-1) levels). Recently, pioglitazone has been shown to inhibit the B form of monoamine oxidase (MAO) in mouse, while rosiglitazone and troglitazone were described as non-covalent inhibitors of both human MAO A and MAO B. Since molecules interacting with MAO might also inhibit semicarbazide-sensitive amine oxidase (SSAO), known as vascular adhesion protein-1 (VAP-1), and since VAP-1/SSAO inhibitors exhibit anti-inflammatory activity, our aim was to elucidate whether VAP-1/SSAO inhibition could be a mechanism involved in the anti-inflammatory behaviour of glitazones. To this aim, MAO and SSAO activities were measured in human subcutaneous adipose tissue biopsies obtained from overweight women undergoing plastic surgery. The production of hydrogen peroxide, an end-product of amine oxidase activity, was determined in tissue homogenates using a fluorometric method. The oxidation of 1 mM tyramine was inhibited by pargyline and almost resistant to semicarbazide, therefore predominantly MAO-dependent. Rosiglitazone was more potent than pioglitazone in inhibiting tyramine oxidation. By contrast, benzylamine oxidation was only abolished by semicarbazide: hence SSAO-mediated. Pioglitazone hampered SSAO activity only when tested at 1 mM while rosiglitazone was inefficient. However, rosiglitazone exhibited anti-inflammatory activity in human adipocytes by limiting MCP-1 expression. Our observations rule out any involvement of VAP-1/SSAO inhibition and subsequent limitation of leukocyte extravasation in the anti-inflammatory action of glitazones.
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Affiliation(s)
- Christian Carpéné
- Institut des Maladies Métaboliques et Cardiovasculaires, Institut National de la Santé et de la Recherche Médicale (INSERM U1048), Toulouse, France,
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Calzadilla P, Gómez-Serrano M, García-Santos E, Schiappacasse A, Abalde Y, Calvo JC, Peral B, Guerra LN. N-Acetylcysteine affects obesity-related protein expression in 3T3-L1 adipocytes. Redox Rep 2014; 18:210-8. [PMID: 24112955 DOI: 10.1179/1351000213y.0000000066] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVES Oxidative stress plays critical roles in the pathogeneses of diabetes, hypertension, and atherosclerosis, but its effect on fat accumulation is still unclear. In this study, we analyzed the role of the well-known antioxidant and a glutathione (GSH) precursor N-acetylcysteine (NAC) in fat accumulation and the expression of obesity-associated proteins. METHODS We studied the effects of 10 µM NAC on obesity-related protein expression in cultured 3T3-L1 preadipocytes, which are able to differentiate into mature adipocytes and accumulate lipids. RESULTS NAC treatment inhibited fat accumulation and reduced the expression of obesity-related proteins, including monoamine oxidase A, heat shock protein 70 (HSP70), aminoacylase -1 (ACY-1), and transketolase. DISCUSSION Our results suggest that the effects of NAC on triglycerides (Tgs) and protein expression are correlated. In support of this, we showed that NAC treatment affected both the Tg synthesis pathway and the expression levels of proteins implicated in human obesity.
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Affiliation(s)
- P Calzadilla
- Universidad de Buenos Aires - IQUIBICEN, CONICET. Intendente Güiraldes 2160, Pabellón 2 (1428), Buenos Aires, Argentina
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28
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Bonaiuto E, Milelli A, Cozza G, Tumiatti V, Marchetti C, Agostinelli E, Fimognari C, Hrelia P, Minarini A, Di Paolo ML. Novel polyamine analogues: From substrates towards potential inhibitors of monoamine oxidases. Eur J Med Chem 2013; 70:88-101. [DOI: 10.1016/j.ejmech.2013.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/09/2013] [Accepted: 07/12/2013] [Indexed: 01/12/2023]
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Skårn M, Barøy T, Stratford EW, Myklebost O. Epigenetic regulation and functional characterization of microRNA-142 in mesenchymal cells. PLoS One 2013; 8:e79231. [PMID: 24236112 PMCID: PMC3827369 DOI: 10.1371/journal.pone.0079231] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 09/19/2013] [Indexed: 12/25/2022] Open
Abstract
The transcripts encoded by the microRNA mir-142 gene are highly active in hematopoietic cells, but expressed at low levels in many other cell types. Treatment with the demethylating agent 5-Aza-2′-deoxycytidine increased both the 1,636 nucleotide primary transcript and mature miR-142-5p/3p in mesenchymal cells, indicating that mir-142 is epigenetically repressed by DNA methylation. The transcription start site was determined to be located 1,205 base pairs upstream of the precursor sequence within a highly conserved CpG island. In addition, a second CpG island overlapped with the precursor. A TATA-box, several promoter-proximal elements and enrichment of conserved transcription factor binding sites within the first 100 base pairs upstream of the transcription start site, suggests that this region represents the core/proximal mir-142 promoter. Moreover, both CpG islands were heavily methylated in mesenchymal cells, having low levels of miR-142-5p/3p, and unmethylated in hematopoietic cells where both miRNAs were abundantly expressed. We show that treatment with 5-Aza-2′-deoxycytidine significantly reduced the DNA methylation of the upstream CpG island, which led to increased expression, and that in vitro DNA methylation of the upstream region of the mir-142 precursor repressed its transcriptional activity. When overexpressed, miR-142-5p/3p reduced proliferation of cells with epigenetic silencing of endogenous mir-142. This finding is interesting as miR-142-5p/3p have been reported to be deregulated in tumors of mesenchymal origin. We provide the first experimental evidence that transcription of mir-142 is directly repressed by DNA methylation. In addition, we discovered that the antisense strand of mir-142 might act as a precursor for functional mature antisense miRNAs. Thus, our study expands the current knowledge about the regulation of mir-142 and function of miR-142-5p/3p, and adds novel insight into the rapidly increasing field of microRNA regulation.
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Affiliation(s)
- Magne Skårn
- Department of Tumor Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
- * E-mail:
| | - Tale Barøy
- Department of Tumor Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Eva Wessel Stratford
- Department of Tumor Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
- Cancer Stem Cell Innovation Centre, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Ola Myklebost
- Department of Tumor Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
- Norwegian Stem Cell Centre, Oslo University Hospital, Oslo, Norway
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Grès S, Canteiro S, Mercader J, Carpéné C. Oxidation of high doses of serotonin favors lipid accumulation in mouse and human fat cells. Mol Nutr Food Res 2013; 57:1089-99. [DOI: 10.1002/mnfr.201200681] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 12/04/2012] [Accepted: 12/21/2012] [Indexed: 01/25/2023]
Affiliation(s)
| | - Sarah Canteiro
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC); Université de Toulouse; UPS; Toulouse; France
| | - Josep Mercader
- Institut National de la Santé et de la Recherche Médicale; INSERM U1048; Toulouse; France
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Grès S, Gomez-Zorita S, Gomez-Ruiz A, Carpéné C. 5-hydroxytryptamine actions in adipocytes: involvement of monoamine oxidase-dependent oxidation and subsequent PPARγ activation. J Neural Transm (Vienna) 2012; 120:919-26. [PMID: 23271029 DOI: 10.1007/s00702-012-0959-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 12/11/2012] [Indexed: 11/26/2022]
Abstract
Serotonin (5-HT) is a brain neurotransmitter instrumental for the antidepressant action of selective inhibitors of serotonin reuptake (SSRIs) while it also plays important roles in peripheral organs. Recently, the 5-HT oxidation products, 5-hydroxyindoleacetate and 5-methoxy-indoleacetate, have been shown to bind to peroxisome proliferator-activated receptor γ (PPARγ) and to enhance lipid accumulation in preadipocytes. Since we already reported that adipocytes exhibit elevated monoamine oxidase (MAO) and primary amine oxidase activities, we verified how adipocytes readily oxidize 5-HT, with the objective to determine whether such oxidation promotes PPARγ activation and lipid storage. To this aim, serotonin was tested on cultured 3T3 F442A preadipocytes and on human adipocytes. Results showed that 5-HT was oxidized by MAO in both models. Daily treatment of 3T3 F442A preadipocytes for 8 days with 100-500 μM 5-HT promoted triglyceride accumulation and emergence of adipogenesis markers. At 250 μM, 5-HT alone reproduced half of 50 nM insulin-induced adipogenesis, and exhibited an additive differentiating effect when combined with insulin. Moreover, the 5-HT-induced expression of PPARγ-responsive genes (PEPCK, aP2/FABP4) was blocked by GW 9662, a PPARγ-inhibitor, or by pargyline, a MAO-inhibitor. In human fat cells, 6-h exposure to 100 μM 5-HT increased PEPCK expression as did the PPARγ-agonist rosiglitazone. Since hydrogen peroxide, another amine oxidation product, did not reproduce such enhancement, we propose that serotonin can promote PPARγ activation in fat cells, via the indoleacetate produced during MAO-dependent oxidation. Such pathway could be involved in the adverse effects of several antidepressant SSRIs on body weight gain.
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Affiliation(s)
- Sandra Grès
- Université de Toulouse, UPS, Institut de Médecine Moléculaire de Rangueil (I2MC), Toulouse, France
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Kvetnansky R, Ukropec J, Laukova M, Manz B, Pacak K, Vargovic P. Stress stimulates production of catecholamines in rat adipocytes. Cell Mol Neurobiol 2012; 32:801-13. [PMID: 22402834 PMCID: PMC3419009 DOI: 10.1007/s10571-012-9822-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 02/17/2012] [Indexed: 11/28/2022]
Abstract
The sympathoadrenal system is the main source of catecholamines (CAs) in adipose tissues and therefore plays the key role in the regulation of adipose tissue metabolism. We recently reported existence of an alternative CA-producing system directly in adipose tissue cells, and here we investigated effect of various stressors-physical (cold) and emotional stress (immobilization) on dynamics of this system. Acute or chronic cold exposure increased intracellular norepinephrine (NE) and epinephrine (EPI) concentration in isolated rat mesenteric adipocytes. Gene expression of CA biosynthetic enzymes did not change in adipocytes but was increased in stromal vascular fraction (SVF) after 28 day cold. Exposure of rats to a single IMO stress caused increases in NE and EPI levels, and also gene expression of CA biosynthetic enzymes in adipocytes. In SVF changes were similar but more pronounced. Animals adapted to a long-term cold exposure (28 days, 4°C) did not show those responses found after a single IMO stress either in adipocytes or SVF. Our data indicate that gene machinery accommodated in adipocytes, which is able to synthesize NE and EPI de novo, is significantly activated by stress. Cold-adapted animals keep their adaptation even after an exposure to a novel stressor. These findings suggest the functionality of CAs produced endogenously in adipocytes. Taken together, the newly discovered CA synthesizing system in adipocytes is activated in stress situations and might significantly contribute to regulation of lipolysis and other metabolic or thermogenetic processes.
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Affiliation(s)
- R Kvetnansky
- Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
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Pérez-Pérez R, García-Santos E, Ortega-Delgado FJ, López JA, Camafeita E, Ricart W, Fernández-Real JM, Peral B. Attenuated metabolism is a hallmark of obesity as revealed by comparative proteomic analysis of human omental adipose tissue. J Proteomics 2012; 75:783-95. [DOI: 10.1016/j.jprot.2011.09.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 09/19/2011] [Accepted: 09/22/2011] [Indexed: 01/11/2023]
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Adipocytes as a new source of catecholamine production. FEBS Lett 2011; 585:2279-84. [PMID: 21689652 DOI: 10.1016/j.febslet.2011.06.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 04/28/2011] [Accepted: 06/01/2011] [Indexed: 01/14/2023]
Abstract
Catecholamines are an important regulator of lipolysis in adipose tissue. Here we show that rat adipocytes, isolated from mesenteric adipose tissue, express genes of catecholamine biosynthetic enzymes and produce catecholamines de novo. Administration of tyrosine hydroxylase inhibitor, alpha-methyl-p-tyrosine, in vitro significantly reduced concentration of catecholamines in isolated adipocytes. We hypothesize that the sympathetic innervation of adipose tissues is not the only source of catecholamines, since adipocytes also have the capacity to produce both norepinephrine and epinephrine.
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Chiche F, Le Guillou M, Chétrite G, Lasnier F, Dugail I, Carpéné C, Moldes M, Fève B. Antidepressant phenelzine alters differentiation of cultured human and mouse preadipocytes. Mol Pharmacol 2009; 75:1052-61. [PMID: 19201819 DOI: 10.1124/mol.108.052563] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Change in body weight is a frequent side effect of antidepressants and is considered to be mediated by central effects on food intake and energy expenditure. The antidepressant phenelzine (Nardil) potently inhibits both monoamine oxidase and semicarbazide-sensitive amine oxidase activities, two enzymes that are highly expressed in adipose tissue, raising the possibility that it could directly alter adipocyte biology. Treatment with this compound is rather associated with weight gain. The aim of this work was to examine the effects of phenelzine on differentiation and metabolism of cultured human and mouse preadipocytes and to characterize the mechanisms involved in these effects. In all preadipocyte models, phenelzine induced a time- and dose-dependent reduction in differentiation and triglyceride accumulation. Modulation of lipolysis or glucose transport was not involved in phenelzine action. This effect was supported by the reduced expression in the key adipogenic transcription factors peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and CCAAT/enhancer binding protein-alpha, which was observed only at the highest drug concentrations (30-100 microM). The PPAR-gamma agonists thiazolidinediones did not reverse phenelzine effects. By contrast, the reduction in both cell triglycerides and sterol regulatory element-binding protein-1c (SREBP-1c) was detectable at lower phenelzine concentrations (1-10 microM). Phenelzine effect on triglyceride content was prevented by providing free fatty acids to the cells and was partially reversed by overexpression of a dominant-positive form of SREBP-1c, showing the privileged targeting of the lipogenic pathway. When considered together, these findings demonstrate that an antidepressant directly and potently inhibits adipocyte lipid storage and differentiation, which could contribute to psychotropic drug side effects on energy homeostasis.
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Affiliation(s)
- Françoise Chiche
- Institut National de la Santé et de la Recherche Médicale U693, University Paris-Sud, Faculté de Médecine, Le Kremlin-Bicêtre, France
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Adams F, Boschmann M, Lobsien E, Kupsch A, Lipp A, Franke G, Leisse MC, Janke J, Gottschalk S, Spranger J, Jordan J. Influences of levodopa on adipose tissue and skeletal muscle metabolism in patients with idiopathic Parkinson’s disease. Eur J Clin Pharmacol 2008; 64:863-70. [DOI: 10.1007/s00228-008-0532-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Accepted: 06/27/2008] [Indexed: 11/29/2022]
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Takao Y, Fujiwara H, Yoshioka S, Fujii S, Ueda M. Monoamine oxidase A is highly expressed by the human corpus luteum of pregnancy. Reproduction 2008; 136:367-75. [PMID: 18499710 DOI: 10.1530/rep-08-0004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To investigate the physiological characteristics of the corpus luteum (CL) of pregnancy, we raised a mAb, human corpus luteum (HCL)-4, against human luteal cells obtained from CL of pregnancy. The affinity-purified antigen from human CL of pregnancy or placenta using HCL-4 was a 61 kDa protein. The partial amino acid sequence of the antigenic protein was identical to that of human monoamine oxidase A (MAOA, EC1.4.3.4). MAOA has been shown to catabolize catecholamines that were reported to regulate luteal function in CL and vasoconstriction in various organs. Immunohistochemistry using HCL-4 mAb showed that MAOA was intensely expressed on large luteal cells and moderately expressed on small luteal cells in the CL of pregnancy. In the CL of menstrual cycle, MAOA was weakly detected on large luteal cells but not detected at all on small luteal cells. Western blotting analysis confirmed the high expression of MAOA in CL of pregnancy. Northern blot analysis also showed the expression of MAOA mRNA in human CL, and showed that its expression was higher in CL of pregnancy than in CL of menstrual cycle. The increased expression of MAOA in the CL of pregnancy suggests the contribution of MAOA to the function of the CL of pregnancy.
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Affiliation(s)
- Yumi Takao
- Department of Gynecology and Obstetrics, Faculty of Medicine Institute for Virus Research, Kyoto University, Sakyo-Ku, Kyoto 606, Japan
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Bour S, Daviaud D, Gres S, Lefort C, Prévot D, Zorzano A, Wabitsch M, Saulnier-Blache JS, Valet P, Carpéné C. Adipogenesis-related increase of semicarbazide-sensitive amine oxidase and monoamine oxidase in human adipocytes. Biochimie 2007; 89:916-25. [PMID: 17400359 DOI: 10.1016/j.biochi.2007.02.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Accepted: 02/16/2007] [Indexed: 02/08/2023]
Abstract
A strong induction of semicarbazide-sensitive amine oxidase (SSAO) has previously been reported during murine preadipocyte lineage differentiation but it remains unknown whether this emergence also occurs during adipogenesis in man. Our aim was to compare SSAO and monoamine oxidase (MAO) expression during in vitro differentiation of human preadipocytes and in adipose and stroma-vascular fractions of human fat depots. A human preadipocyte cell strain from a patient with Simpson-Golabi-Behmel syndrome was first used to follow amine oxidase expression during in vitro differentiation. Then, human preadipocytes isolated from subcutaneous adipose tissues were cultured under conditions promoting ex vivo adipose differentiation and tested for MAO and SSAO expression. Lastly, human adipose tissue was separated into mature adipocyte and stroma-vascular fractions for analyses of MAO and SSAO at mRNA, protein and activity levels. Both SSAO and MAO were increased from undifferentiated preadipocytes to lipid-laden cells in all the models: 3T3-F442A and 3T3-L1 murine lineages, human SGBS cell strain or human preadipocytes in primary culture. In human subcutaneous adipose tissue, the adipocyte-enriched fraction exhibited seven-fold higher amine oxidase activity and contained three- to seven-fold higher levels of mRNAs encoded by MAO-A, MAO-B, AOC3 and AOC2 genes than the stroma-vascular fraction. MAO-A and AOC3 genes accounted for the majority of their respective MAO and SSAO activities in human adipose tissue. Most of the SSAO and MAO found in adipose tissue originated from mature adipocytes. Although the mechanism and role of adipogenesis-related increase in amine oxidase expression remain to be established, the resulting elevated levels of amine oxidase activities found in human adipocytes may be of potential interest for therapeutic intervention in obesity.
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Affiliation(s)
- Sandy Bour
- U858 INSERM, I2MR, IFR 31, CHU Rangueil, BP 84225, 31432 Toulouse Cedex 4, France
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Wanecq E, Bour S, Verwaerde P, Smih F, Valet P, Carpéné C. Increased monoamine oxidase and semicarbazide-sensitive amine oxidase activities in white adipose tissue of obese dogs fed a high-fat diet. J Physiol Biochem 2007; 62:113-23. [PMID: 17217165 DOI: 10.1007/bf03174072] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Adipocytes express two types of amine oxidases: the cell surface semicarbazide-sensitive amine oxidase (SSAO) and the mitochondrial monoamine oxidase (MAO). In human abdominal subcutaneous adipose tissue, it has been reported that SSAO substrates stimulate glucose transport and inhibit lipolysis while MAO activity is decreased in obese patients when compared to age-matched controls. However, no information has been reported on visceral WAT. To further investigate the obesity-induced regulations of MAO and SSAO in white adipose tissue (WAT) from different anatomical locations, enzyme activities and mRNA abundance have been determined on tissue biopsies from control and high-fat fed dogs, an obesity model already described to be associated with arterial hypertension and hyperinsulinemia. MAO activity was increased in the enlarged omental WAT of diet-induced obese dogs, but not in their mesenteric WAT, another intra-abdominal fat depot. Subcutaneous WAT did not exhibit any change in MAO activity, as did the richest MAO-containing tissue: liver. Similarly, SSAO was increased in omental WAT of diet-induced obese dogs, but was not modified in other WAT and in aorta. The increase in SSAO activity observed in omental WAT likely results from an increased expression of the AOC3 gene since mRNA abundance and maximal benzylamine oxidation velocity were increased. Finally, plasma SSAO was decreased in obese dogs. Although the observed regulations differ from those found in subcutaneous WAT of obese patients, this canine model shows a tissue- and site-specific regulation of peripheral MAO and SSAO in obesity.
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Affiliation(s)
- E Wanecq
- INSERM U586, IFR 31, Bat. L3, CHU Rangueil, 31432 Toulouse, France
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Carpéné C, Daviaud D, Boucher J, Bour S, Visentin V, Grès S, Duffaut C, Fontana E, Testar X, Saulnier-Blache JS, Valet P. Short- and long-term insulin-like effects of monoamine oxidases and semicarbazide-sensitive amine oxidase substrates in cultured adipocytes. Metabolism 2006; 55:1397-405. [PMID: 16979412 DOI: 10.1016/j.metabol.2006.06.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Accepted: 06/16/2006] [Indexed: 01/12/2023]
Abstract
Semicarbazide-sensitive amine oxidase (SSAO) is known to increase during in vitro adipogenesis and to be one of the most highly expressed membrane proteins of white adipocytes. Although less well documented, mitochondrial monoamine oxidases (MAOs) are also present in adipocytes and share with SSAO the capacity to generate hydrogen peroxide. This work therefore aimed to compare several biologic effects of MAO and SSAO substrates in 3T3-F442A adipocytes. In differentiated cells, tyramine oxidation was predominantly MAO dependent, whereas benzylamine oxidation was SSAO dependent. Both amines partially mimicked insulin actions, including stimulation of Akt phosphorylation and glucose uptake. In addition, tyramine and benzylamine impaired tumor necrosis factor alpha-dependent nitric oxide formation in a pargyline- and semicarbazide-sensitive manner, respectively. Various biogenic amines were tested in competition for tyramine or benzylamine oxidation and classified as MAO-preferring (methoxytyramine, tryptamine) or SSAO-preferring substrates (methylamine, octopamine). Short-term incubation with 1 mmol/L of all amines except histamine stimulated glucose uptake up to 20% to 50% of maximal insulin activation. One-week treatment with either MAO or SSAO substrates alone allowed postconfluent cells to differentiate into adipocytes, reproducing 60% of insulin-promoted lipid accumulation. All amines also exerted a slight improvement in the adipogenic action of insulin. Therefore, like SSAO, substrate activation of MAO can interact with adipocyte metabolism by mimicking diverse effects of insulin in addition to preventing tumor necrosis factor alpha-dependent responses.
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Affiliation(s)
- Christian Carpéné
- Institut National de la Santé et de la Recherche Médicale, U586 INSERM, IFR 31, CHU Rangueil, 31432 Toulouse cedex 4, France.
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Bour S, Iglesias-Osma MC, Marti L, Duro P, Garcia-Barrado MJ, Pastor MF, Prévot D, Visentin V, Valet P, Moratinos J, Carpéné C. The imidazoline I2-site ligands BU 224 and 2-BFI inhibit MAO-A and MAO-B activities, hydrogen peroxide production, and lipolysis in rodent and human adipocytes. Eur J Pharmacol 2006; 552:20-30. [PMID: 17056035 DOI: 10.1016/j.ejphar.2006.09.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 09/07/2006] [Accepted: 09/11/2006] [Indexed: 12/31/2022]
Abstract
Numerous imidazolinic agents exhibit antihyperglycaemic properties and have been described to promote insulin secretion, however their effects on adipose tissue development have been poorly investigated. Since white adipose tissue (WAT) plays an important role in glucose homeostasis and expresses imidazoline (I(2)) binding sites abundantly, this work aimed at studying extrapancreatic actions of two I(2)-site ligands, BU 224 and 2-BFI in adipocytes. Interaction with monoamine oxidase (MAO) was investigated by measuring the ability to modulate [(14)C]tyramine oxidation and hydrogen peroxide production. Direct influence on glucose uptake or on lipolytic activity was tested on mouse, rat, rabbit and human adipocytes. BU 224 and 2-BFI behaved as reversible inhibitors of both MAO-A and -B, as demonstrated by total inhibition of tyramine oxidation in human adipocytes and platelets or in liver from rats previously treated with selective MAO-inhibitors. Moreover, they weakly inhibited semicarbazide-sensitive amine oxidase. Like classical MAO-inhibitors, they were unable to produce hydrogen peroxide and to activate glucose uptake but prevented tyramine to do so in rodent or human adipocytes. BU 224 and 2-BFI also differed from MAO-inhibitors since they inhibited lipolysis at millimolar concentrations via a still undefined pathway independent of alpha(2)-adrenoceptor stimulation, beta-adrenergic antagonism and MAO activation. However, chronic treatment of obese Zucker rats with 2-BFI did not modify the maximal lipolytic capacity or the mild insulin resistance status of their adipocytes. Taken together, our observations demonstrate on WAT novel effects of BU 224 and 2-BFI different from their already reported actions on brain or endocrine pancreas.
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Affiliation(s)
- Sandy Bour
- Inserm, U586, Unité de Recherches sur les Obésités, Université Paul Sabatier, IFR31, CHU Rangueil, Toulouse, F-31432, France
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Carpéné C, Visentin V, Morin N, Prévot D, Smih F, Rouet P, Jayat D, Fontana E, Lizcano JM. Characterization of semicarbazide-sensitive amine oxidase in human subcutaneous adipocytes and search for novel functions. Inflammopharmacology 2004; 11:119-26. [PMID: 15035813 DOI: 10.1163/156856003765764281] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Numerous studies have characterized semicarbazide-sensitive amine oxidase activity (SSAO) in rat fat cells but this oxidase is scarcely documented in human adipose tissue. Our aim was to further characterize SSAO in human adipose tissue (activity, mRNA and protein abundance) and to investigate whether SSAO activity can interplay with glucose and lipid metabolism in human adipocytes via the hydrogen peroxide it generates. Polyclonal antibodies directed against bovine lung SSAO allowed the detection of a substantial amount of immunoreactive protein (apparent molecular mass 100 kDa) in human subcutaneous adipocytes from either mammary or abdominal fat depots. A 4-kb mRNA was detected in fat depots using a cDNA probe designed from the placenta SSAO sequence. Almost all the oxidation of benzylamine found in adipose tissue homogenates was due to fat cells and was located in the adipocyte membrane fraction. The oxidation of benzylamine and methylamine were similar and totally inhibited by semicarbazide or hydralazine but resistant to pargyline. Histamine was poorly oxidized. Benzylamine and methylamine dose-dependently stimulated glucose transport in intact adipocytes. This insulin-like effect of amines did not increase in the presence of 0.1 mM vanadate but was inhibited by semicarbazide and antioxidants. Benzylamine and methylamine also exhibited antilipolytic effects, with complete inhibition of lipolysis at 1 mM. These results show that fat cells from non-obese subjects express a membrane-bound SSAO which readily oxidizes exogenous amines, generates hydrogen peroxide and exerts short-term insulin-like actions on glucose and lipid metabolism.
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Affiliation(s)
- C Carpéné
- U317 INSERM, IFR 31, Bat. L3, CHU Rangueil, 31403 Toulouse, France.
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Ballart X, Siches M, Peinado-Onsurbe J, López-Tejero D, Llobera M, Ramírez I, Robert MQ. Isoproterenol increases active lipoprotein lipase in adipocyte medium and in rat plasma. Biochimie 2004; 85:971-82. [PMID: 14644552 DOI: 10.1016/j.biochi.2003.09.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
White adipose tissue (WAT) lipoprotein lipase (LPL) activity channels diet fat towards storage in adipocytes. Adrenaline (ADR) is accepted to reduce WAT or adipocyte LPL activity (LPLa), but available data are not clear-cut regarding long exposure to ADR in vitro or in vivo. We studied the effects of long exposures to ADR or beta-adrenergic agonist on LPL: in isolated rat adipocytes (3 h) and in rats (>1 day). Isoproterenol (ISO) (1 microM) did not alter LPLmRNA nor LPLa in adipocytes, but increased LPLa in medium more than twofold (3.58 +/- 0.35 vs. 1.32 +/- 0.35 mU/10(6) adipocytes, P < 0.001). Effect was time (not present at 1 h, clear at 2 h) and concentration dependent (high sensitivity from 10 to 100 nM, max at 1 microM). Adenylate cyclase activator or cyclic AMP (cAMP) analogue produced a similar increase. Thus in adipocytes ISO produced an increase in LPLa release and/or a decrease in extracellular LPLa degradation. ADR or ISO treated rats had a two to fourfold decrease in WAT LPLa vs. unchanged LPLmRNA. This decrease was 10-fold in WAT heparin-releasable LPLa (5.7 +/- 0.6 vs. 57.3 +/- 10.2 mU/g, P < 0.001), which represents peri/extracellular LPLa. Plasma LPLa was increased 11-fold by ADR (3.30 +/- 0.58 vs. 0.32 +/- 0.08 mU/ml, P < 0.001) whereas only threefold by ISO (P > 0.01). We suggest that in vivo ADR increased release of active LPL to plasma from endothelial cells of LPL-rich tissue(s)-WAT was probably one of these tissues releasing LPL since it lost 90% of its peri/extracellular LPLa-and/or decreased degradation of plasma active LPL. Since liver LPLa was not increased, plasma active LPL might be kept away from hepatic degradation by binding to stabilising entities in plasma (fatty acids (FA), lipoproteins or soluble heparan sulphates (HS)). In conclusion, we believe this is the first report stating that: (a) ISO increases LPLa in isolated adipocyte medium, and (b) ADR administration to rats decreases WAT extracellular active LPL and increases preheparin plasma active LPL.
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Affiliation(s)
- Xavier Ballart
- Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain
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Visentin V, Prévot D, De Saint Front VD, Morin-Cussac N, Thalamas C, Galitzky J, Valet P, Zorzano A, Carpéné C. Alteration of amine oxidase activity in the adipose tissue of obese subjects. ACTA ACUST UNITED AC 2004; 12:547-55. [PMID: 15044673 DOI: 10.1038/oby.2004.62] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVE To explore the activity of monoamine oxidases (MAOs) and semicarbazide-sensitive amine oxidases (SSAOs) in adipose tissue and blood of lean and moderately obese subjects and to study whether there is a link between these hydrogen peroxide-generating enzymes and blood markers of oxidative stress. RESEARCH METHODS AND PROCEDURES Nine obese male subjects (BMI 32.6 +/- 0.4 kg/m(2)) and nine controls (BMI 23.4 +/- 0.5) of 24- to 40-year-old subjects were included in the study. MAO and SSAO activities were measured on microbiopsies of abdominal subcutaneous adipose tissue by quantifying (14)C-tyramine and (14)C-benzylamine oxidation. Levels of soluble SSAO, lipid peroxidation products, and antioxidant agents were measured in plasma, whereas cytoprotective enzymes were determined in blood lysates. RESULTS The high MAO activity found in adipose tissue was diminished by one-half in obese subjects (maximum initial velocity of 1.2 vs. 2.3 nmol tyramine oxidized/mg protein/min). There was no change in SSAO activity, either under its adipose tissue-bound or plasma-soluble form. Plasma levels of lipid peroxidation products and antioxidant vitamins remained unmodified, as well as erythrocyte antioxidant enzymes, whereas circulating triglycerides, insulin, and leptin were increased. DISCUSSION Although they already exhibited several signs of endocrino-metabolic disorders, the obese men did not exhibit the increase in blood markers of oxidative stress or the decrease in antioxidant defenses reported to occur in very obese or diabetic subjects. The reduced MAO and the unchanged SSAO activities found in obesity suggest that these hydrogen peroxide-generating enzymes expressed in adipocytes are probably not involved in the onset of the oxidative stress found in severe obesity and/or in its complications.
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Affiliation(s)
- Virgile Visentin
- Institut National de la Santé et de la Recherche Médicale, Centre Hospitalier Universitaire Rangueil, Toulouse, France
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Visentin V, Prévot D, Marti L, Carpéné C. Inhibition of rat fat cell lipolysis by monoamine oxidase and semicarbazide-sensitive amine oxidase substrates. Eur J Pharmacol 2003; 466:235-43. [PMID: 12694806 DOI: 10.1016/s0014-2999(03)01562-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
It has been demonstrated that amine oxidase substrates stimulate glucose transport in cardiomyocytes and adipocytes, promote adipogenesis in pre-adipose cell lines and lower blood glucose in diabetic rats. These insulin-like effects are dependent on amine oxidation by semicarbazide-sensitive amine oxidase or by monoamine oxidase. The present study aimed to investigate whether amine oxidase substrates also exhibit another insulin-like property, the inhibition of lipolysis. We therefore tested the influence of tyramine and benzylamine on lipolytic activity in rat adipocytes. These amines did not modify basal lipolysis but dose-dependently counteracted the stimulation induced by lipolytic agents. The response to 10 nM isoprenaline was totally inhibited by tyramine 1 mM. The blockade produced by inhibition of amine oxidase activity or by 1 mM glutathione suggested that the generation of oxidative species, which occurs during amine oxidation, was involved in tyramine antilipolytic effect. Among the products resulting from amine oxidation, only hydrogen peroxide was antilipolytic in a manner that was potentiated by vanadate, as for tyramine or benzylamine. Antilipolytic responses to tyramine and to insulin were sensitive to wortmannin. These data suggest that inhibition of lipolysis is a novel insulin-like effect of amine oxidase substrates which is mediated by hydrogen peroxide generated during amine oxidation.
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Affiliation(s)
- Virgile Visentin
- Institut Louis Bugnard, Institut National de la Santé et de la Recherche Médicale, Unité 586, C.H.U. Rangueil, Toulouse Cedex F-31403, France
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Mercier N, Moldes M, El Hadri K, Fève B. Regulation of semicarbazide-sensitive amine oxidase expression by tumor necrosis factor-alpha in adipocytes: functional consequences on glucose transport. J Pharmacol Exp Ther 2003; 304:1197-208. [PMID: 12604697 DOI: 10.1124/jpet.102.044420] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Membrane-associated semicarbazide-sensitive amine oxidase (SSAO) is mainly present in the media of aorta and in adipose tissue. Recent works have reported that SSAO activation can stimulate glucose transport of fat cells and promote adipose conversion. In this study, the murine 3T3-L1 preadipose cell line was used to investigate SSAO regulation by tumor necrosis factor-alpha (TNF-alpha), a cytokine that is synthesized in fat cells and known to be involved in obesity-linked insulin resistance. SSAO mRNA and protein levels, and enzyme activity were decreased by TNF-alpha in a dose- and time-dependent manner, without any change of SSAO affinity for substrates or inhibitors. SSAO inhibition caused by TNF-alpha was spontaneously reversed along the time after TNF-alpha removal. The decrease in SSAO expression also occurred in white adipose tissue of C57BL/6 mice treated with mTNF-alpha. Overall, we demonstrated that reduction in SSAO expression induced by the cytokine had marked repercussions on amine-stimulated glucose transport, in a dose- and time-dependent manner. This effect was more pronounced than the inhibiting effect of TNF-alpha on insulin-stimulated glucose transport. Moreover, the peroxisome proliferator-activated receptor gamma agonists thiazolidinediones did not reverse either TNF-alpha effect on amine-sensitive glucose transport or the inhibition of SSAO activity, whereas they antagonized TNF-alpha effects on insulin-sensitive glucose transport. These results demonstrate that TNF-alpha can strongly down-regulate SSAO expression and activity, and through this mechanism can dramatically reduce amine-stimulated glucose transport. This suggests a potential role of this regulatory process in the pathogenesis of glucose homeostasis dysregulations observed during diseases accompanied by TNF-alpha overproduction, such as cachexia or obesity.
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Affiliation(s)
- Nathalie Mercier
- Unité Mixte de Recherche 7079, CNRS-Paris VI, Centre de Recherches Biomédicales des Cordeliers, Paris, France
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Morin N, Visentin V, Calise D, Marti L, Zorzano A, Testar X, Valet P, Fischer Y, Carpéné C. Tyramine stimulates glucose uptake in insulin-sensitive tissues in vitro and in vivo via its oxidation by amine oxidases. J Pharmacol Exp Ther 2002; 303:1238-47. [PMID: 12438548 DOI: 10.1124/jpet.102.040592] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Tyramine and benzylamine have been described as stimulators of glucose transport in adipocytes. This effect is dependent on amine oxidation by monoamine oxidase (MAO) or semicarbazide-sensitive amine oxidase (SSAO) and on the subsequent hydrogen peroxide formation as already demonstrated by blockade with oxidase inhibitors or antioxidants and potentiation with vanadate. In this work, we extended these observations to skeletal muscle and cardiac myocytes using in vitro and in vivo approaches. Tissue distribution studies showed that substantial extrahepatic peripheral MAO activities exist in kidney and gut, but also in insulin-sensitive tissues: heart, adipose tissue, and skeletal muscles. SSAO activity is also widely distributed and present at a lower level than MAO, except in fat depots where both oxidases were equally involved in tyramine oxidation. When tested in vitro at millimolar doses, tyramine caused a large stimulation of glucose transport in rat adipocytes and in skeletal and cardiac muscles. In vivo administration of tyramine (4 mg/kg i.p.) lowered the hyperglycemic responses to a glucose challenge in control and in streptozotocin-treated rats. This positive effect on glucose disposal was obtained without vanadate and was abolished by SSAO and MAO inhibitors. Tyramine increased hexose uptake in vivo in insulin-sensitive tissues, whereas it induced only transient effects on plasma insulin or cardiovascular parameters. In conclusion, activation of the amine oxidases present in insulin-sensitive tissues induces insulin-like effects, readily detectable in vitro, and increasing peripheral glucose utilization in vivo.
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Affiliation(s)
- Nathalie Morin
- Institut National de la Santé et de la Recherche Médicale, Toulouse, France
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Mercier N, Moldes M, El Hadri K, Fève B. Semicarbazide-sensitive amine oxidase activation promotes adipose conversion of 3T3-L1 cells. Biochem J 2001; 358:335-42. [PMID: 11513731 PMCID: PMC1222065 DOI: 10.1042/0264-6021:3580335] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Semicarbazide-sensitive amine oxidase (SSAO) is an amine oxidase related to the copper-containing amine oxidase family. The tissular form of SSAO is located at the plasma membrane, and is mainly expressed in vascular smooth muscle cells and adipocytes. Recent studies have suggested that SSAO could activate glucose transport in fat cells. In the present work, we investigated the potential role of a chronic SSAO activation on adipocyte maturation of the 3T3-L1 pre-adipose cell line. Exposure of post-confluent 3T3-L1 pre-adipocytes to methylamine, a physiological substrate of SSAO, promoted adipocyte differentiation in a time- and dose-dependent manner. This effect could be related to SSAO activation, since it was antagonized in the presence of the SSAO inhibitor semicarbazide, but not in the presence of the monoamine oxidase inhibitor pargyline. In addition, methylamine-induced adipocyte maturation was mimicked by 3T3-L1 cell treatment with other SSAO substrates. Finally, the large reversion of methylamine action by catalase indicated that hydrogen peroxide generated by SSAO was involved, at least in part, in the modulation of adipocyte maturation. Taken together, our results suggest that SSAO may contribute to the control of adipose tissue development.
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Affiliation(s)
- N Mercier
- Centre de Recherches Biomédicales des Cordeliers, Université Pierre et Marie Curie, UMR 7079 CNRS, 15 rue de l'Ecole de Médecine, 75270 Paris, Cedex 06, France
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Fontana E, Boucher J, Marti L, Lizcano JM, Testar X, Zorzano A, Carpéné C. Amine oxidase substrates mimic several of the insulin effects on adipocyte differentiation in 3T3 F442A cells. Biochem J 2001; 356:769-77. [PMID: 11389684 PMCID: PMC1221903 DOI: 10.1042/0264-6021:3560769] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We have previously reported that substrates of monoamine oxidase (MAO) and semicarbazide-sensitive amine oxidase (SSAO) exert short-term insulin-like effects in rat adipocytes, such as stimulation of glucose transport. In the present work, we studied whether these substrates could also mimic long-term actions of insulin. Adipose differentiation of 3T3 F442A cells, which is highly insulin-dependent, served as a model to test the effects of sustained administration of amine oxidase substrates. Daily treatment of confluent cells with 0.75 mM tyramine (a substrate of MAO and SSAO) or benzylamine (a substrate of SSAO) over 1 week caused the acquisition of typical adipocyte morphology. The stimulation of protein synthesis and triacylglycerol accumulation caused by tyramine or benzylamine reached one half of that promoted by insulin. This effect was insensitive to pargyline (an MAO inhibitor), but was inhibited by semicarbazide (an SSAO inhibitor) and by N-acetylcysteine (an antioxidant agent), suggesting the involvement of the H(2)O(2) generated during SSAO-dependent amine oxidation. Chronic administration of amine oxidase substrates also induced the emergence of adipose conversion markers, such as aP2, glycerol-3-phosphate dehydrogenase, the glucose transporter GLUT4, and SSAO itself. Moreover, cells treated with amines acquired the same insulin sensitivity regarding glucose transport as adipocytes classically differentiated with insulin. In all, most of the adipogenic effects of amines were additive to insulin. Our data reveal that amine oxidase substrates partially mimic the adipogenic effect of insulin in cultured preadipocytes. Furthermore, they suggest that SSAO not only represents a novel late marker of adipogenesis, but could also be directly involved in the triggering of terminal adipocyte differentiation.
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Affiliation(s)
- E Fontana
- Institut National de la Santé et de la Recherche Médicale, Unité 317, Institut Fédératif de Recherches 31, CHU Rangueil, 31403 Toulouse, France
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Ritchie JW, Collingwood CJ, Taylor PM. Effect of hypothyroidism on pathways for iodothyronine and tryptophan uptake into rat adipocytes. Am J Physiol Endocrinol Metab 2001; 280:E254-9. [PMID: 11158928 DOI: 10.1152/ajpendo.2001.280.2.e254] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adipocytes are an important target tissue for thyroid hormone action, but little is known of the mechanisms of thyroid hormone entry into the cells. The present results show a strong interaction between transport of iodothyronines [L-thyroxine (T4), L-triiodothyronine (T3), reverse T3 (rT3)], aromatic amino acids, and the System L amino acid transport inhibitor 2-amino[2,2,1]heptane-2-carboxylic acid (BCH) in white adipocytes. System L appears to be a major pathway of iodothyronine and large neutral amino acid entry into these cells in the euthyroid state. We also demonstrate expression of the CD98hc peptide subunit of the System L transporter in adipocyte cell membranes. Experimental hypothyroidism (28-day propylthiouracil treatment) has no significant effect on System L-like transport of the amino acid tryptophan in adipocytes. In contrast, uptake of T3 and especially T4 is substantially reduced in adipocytes from hypothyroid rats, partly due to reduction of the BCH-sensitive transport component. Transport of iodothyronines and amino acids in adipocytes therefore becomes decoupled in the hypothyroid state, as occurs similarly in liver cells. This may be due to downregulation or dissociation of iodothyronine receptors from the System L transporter complex. Regulation of iodothyronine turnover in fat cells by this type of mechanism could contribute significantly to modulation of T4-T3/rT3 metabolism in the hypothyroid state.
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Affiliation(s)
- J W Ritchie
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
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