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El Amine Z, Mauger JF, Imbeault P. Human Preadipocytes Differentiated under Hypoxia following PCB126 Exposure during Proliferation: Effects on Differentiation, Glucose Uptake and Adipokine Profile. Cells 2023; 12:2326. [PMID: 37759548 PMCID: PMC10527447 DOI: 10.3390/cells12182326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/09/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Persistent organic pollutants (POPs) accumulation and hypoxia are two factors proposed to adversely alter adipose tissue (AT) functions in the context of excess adiposity. Studies have shown that preadipocytes exposure to dioxin and dioxin-like POPs have the greatest deleterious impact on rodent and immortalized human preadipocyte differentiation, but evidence on human preadipocytes is lacking. Additionally, hypoxia is known to strongly interfere with the dioxin-response pathway. Therefore, we tested the effects of pre-differentiation polychlorinated biphenyl (PCB)126 exposure at 10 µM for 3 days and subsequent differentiation under hypoxia on human subcutaneous adipocytes (hSA) differentiation, glucose uptake and expression of selected metabolism- and inflammation-related genes. Pre-differentiation PCB126 exposure lowered the adenosine triphosphate (ATP) content, glucose uptake and leptin expression of mature adipocytes but had limited effects on differentiation under normoxia (21% O2). Under hypoxia (3% O2), preadipocytes ability to differentiate was significantly reduced as reflected by significant decreased lipid accumulation and downregulation of key adipocyte genes such as peroxisome proliferator-activated receptor gamma (PPARγ) and adiponectin. Hypoxia increased glucose uptake and glucose transporter 1 (GLUT1) expression but abolished the adipocytes insulin response and GLUT4 expression. The expression of pro-inflammatory adipokine interleukin-6 (IL-6) was slightly increased by both PCB126 and hypoxia, while IL-8 expression was significantly increased only following the PCB126-hypoxia sequence. These observations suggest that PCB126 does not affect human preadipocyte differentiation, but does affect the subsequent adipocytes population, as reflected by lower ATP levels and absolute glucose uptake. On the other hand, PCB126 and hypoxia exert additive effects on AT inflammation, an important player in the development of chronic diseases such as type 2 diabetes and cardiovascular diseases.
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Affiliation(s)
- Zeinab El Amine
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (Z.E.A.); (J.-F.M.)
| | - Jean-François Mauger
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (Z.E.A.); (J.-F.M.)
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (Z.E.A.); (J.-F.M.)
- Institut du savoir Montfort, Hôpital Montfort, Ottawa, ON K1K 0T2, Canada
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2
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Liang H, Yan J, Song K. Comprehensive lipidomic analysis reveals regulation of glyceride metabolism in rat visceral adipose tissue by high-altitude chronic hypoxia. PLoS One 2022; 17:e0267513. [PMID: 35522648 PMCID: PMC9075645 DOI: 10.1371/journal.pone.0267513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 04/10/2022] [Indexed: 11/18/2022] Open
Abstract
Adipose tissue plays a central role in energy substrate homeostasis and is a key regulator of lipid flow throughout these processes. As hypoxia affects lipid metabolism in adipose tissue, we aimed to investigate the effects of high-altitude chronic hypoxia on lipid metabolism in the adipose tissue of rats using a lipidomic analysis approach. Visceral adipose tissues from rats housed in a high-altitude hypoxia environment representing 4,300 m with 14.07% oxygen (hypoxia group) and from rats housed in a low-altitude normoxia environment representing 41 m with 20.95% oxygen (normoxia group) for 8 weeks were analyzed using an ultra-performance liquid chromatography-Orbitrap mass spectrometry system. After 8 weeks, the body weight and visceral adipose tissue weight of the hypoxia group were significantly decreased compared to those of the normoxia group (p < 0.05). The area and diameter of visceral adipose cells in the hypoxia group were significantly smaller than those of visceral adipose cells in the normoxia group (p < 0.05). The results of lipidomic analysis showed a total of 21 lipid classes and 819 lipid species. The total lipid concentration of the hypoxia group was lower than that in the normoxia group (p < 0.05). Concentrations of diacylglycerols and triacylglycerols in the hypoxia group were significantly lower than those in the normoxia group (p < 0.05). Using univariate and multivariate analyses, we identified 74 lipids that were significantly altered between the normoxia and hypoxia groups. These results demonstrate that high-altitude chronic hypoxia changes the metabolism of visceral adipose glycerides, which may potentially modulate other metabolic processes.
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Affiliation(s)
- Hong Liang
- Department of Basic Medical Sciences, Medical College, Qinghai University, Xining, PR, China
| | - Jun Yan
- Cardiovascular Medicine Department, Xuzhou Medical University affiliated Hospital, Xuzhou, PR China
| | - Kang Song
- Endocrinology Department, Qinghai Provincial People’s Hospital, Xining, PR, China
- Qinghai University affiliated Provincial People’s Hospital, Xining, PR, China
- * E-mail:
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3
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Lockridge A, Hanover JA. A nexus of lipid and O-Glcnac metabolism in physiology and disease. Front Endocrinol (Lausanne) 2022; 13:943576. [PMID: 36111295 PMCID: PMC9468787 DOI: 10.3389/fendo.2022.943576] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Although traditionally considered a glucose metabolism-associated modification, the O-linked β-N-Acetylglucosamine (O-GlcNAc) regulatory system interacts extensively with lipids and is required to maintain lipid homeostasis. The enzymes of O-GlcNAc cycling have molecular properties consistent with those expected of broad-spectrum environmental sensors. By direct protein-protein interactions and catalytic modification, O-GlcNAc cycling enzymes may provide both acute and long-term adaptation to stress and other environmental stimuli such as nutrient availability. Depending on the cell type, hyperlipidemia potentiates or depresses O-GlcNAc levels, sometimes biphasically, through a diversity of unique mechanisms that target UDP-GlcNAc synthesis and the availability, activity and substrate selectivity of the glycosylation enzymes, O-GlcNAc Transferase (OGT) and O-GlcNAcase (OGA). At the same time, OGT activity in multiple tissues has been implicated in the homeostatic regulation of systemic lipid uptake, storage and release. Hyperlipidemic patterns of O-GlcNAcylation in these cells are consistent with both transient physiological adaptation and feedback uninhibited obesogenic and metabolic dysregulation. In this review, we summarize the numerous interconnections between lipid and O-GlcNAc metabolism. These links provide insights into how the O-GlcNAc regulatory system may contribute to lipid-associated diseases including obesity and metabolic syndrome.
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4
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Morin R, Goulet N, Mauger JF, Imbeault P. Physiological Responses to Hypoxia on Triglyceride Levels. Front Physiol 2021; 12:730935. [PMID: 34497541 PMCID: PMC8419320 DOI: 10.3389/fphys.2021.730935] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/03/2021] [Indexed: 11/25/2022] Open
Abstract
Hypoxia is a condition during which the body or specific tissues are deprived of oxygen. This phenomenon can occur in response to exposure to hypoxic environmental conditions such as high-altitude, or because of pathophysiological conditions such as obstructive sleep apnea. Circumstances such as these can restrict supply or increase consumption of oxygen, leading to oxyhemoglobin desaturation and tissue hypoxia. In certain cases, hypoxia may lead to severe health consequences such as an increased risk of developing cardiovascular diseases and type 2 diabetes. A potential explanation for the link between hypoxia and an increased risk of developing cardiovascular diseases lies in the disturbing effect of hypoxia on circulating blood lipids, specifically its capacity to increase plasma triglyceride concentrations. Increased circulating triglyceride levels result from the production of triglyceride-rich lipoproteins, such as very-low-density lipoproteins and chylomicrons, exceeding their clearance rate. Considerable research in murine models reports that hypoxia may have detrimental effects on several aspects of triglyceride metabolism. However, in humans, the mechanisms underlying the disturbing effect of hypoxia on triglyceride levels remain unclear. In this mini-review, we outline the available evidence on the physiological responses to hypoxia and their impact on circulating triglyceride levels. We also discuss mechanisms by which hypoxia affects various organs involved in the metabolism of triglyceride-rich lipoproteins. This information will benefit scientists and clinicians interested in the mechanistic of the regulatory cascade responsible for the response to hypoxia and how this response could lead to a deteriorated lipid profile and an increased risk of developing hypoxia-related health consequences.
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Affiliation(s)
- Renée Morin
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Nicholas Goulet
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Jean-François Mauger
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Pascal Imbeault
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada.,Hôpital Montfort, Institut du Savoir Montfort, Ottawa, ON, Canada
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5
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Mahat B, Mauger JF, Imbeault P. Effects of different oxygen tensions on differentiated human preadipocytes lipid storage and mobilisation. Arch Physiol Biochem 2021; 127:37-43. [PMID: 31055955 DOI: 10.1080/13813455.2019.1609995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Adipose tissue expansion has been suggested to impair oxygen (O2) diffusion in the adipose tissue and cause hypoxia. This study aimed at characterising the effects of hypoxia on adipocyte lipid storage and mobilisation functions. Human preadipocytes were exposed to different O2 tensions (3, 10 and 21%) either acutely for 24 h after differentiation (acute exposure) or during differentiation (14d, chronic hypoxia). Lipoprotein lipase (LPL) activity was decreased dose-dependently by both acute and chronic hypoxia (p < .05). Acute exposure to 3, and 10% O2 stimulated the expression of lipid storage gene, while chronic exposure to 3% O2 inhibited the expression of genes involved in lipid storage and mobilisation (p < .05). Acute hypoxia dose-dependently stimulated basal lipolysis. Conversely, chronic hypoxia did not affect basal lipolysis but significantly decreased isoproterenol-stimulated lipolysis (p < .05). In conclusion, the effects of hypoxia on human adipocyte lipid storage and mobilisation functions are complex but could favour ectopic fat deposition.
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Affiliation(s)
- Bimit Mahat
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
| | - Jean-François Mauger
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
| | - Pascal Imbeault
- Behavioral and Metabolic Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
- Institut du savoir Montfort, Hôpital Montfort, Ottawa, Canada
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6
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Wenderott JK, Flesher CG, Baker NA, Neeley CK, Varban OA, Lumeng CN, Muhammad LN, Yeh C, Green PF, O'Rourke RW. Elucidating nanoscale mechanical properties of diabetic human adipose tissue using atomic force microscopy. Sci Rep 2020; 10:20423. [PMID: 33235234 PMCID: PMC7686328 DOI: 10.1038/s41598-020-77498-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 11/11/2020] [Indexed: 01/07/2023] Open
Abstract
Obesity-related type 2 diabetes (DM) is a major public health concern. Adipose tissue metabolic dysfunction, including fibrosis, plays a central role in DM pathogenesis. Obesity is associated with changes in adipose tissue extracellular matrix (ECM), but the impact of these changes on adipose tissue mechanics and their role in metabolic disease is poorly defined. This study utilized atomic force microscopy (AFM) to quantify difference in elasticity between human DM and non-diabetic (NDM) visceral adipose tissue. The mean elastic modulus of DM adipose tissue was twice that of NDM adipose tissue (11.50 kPa vs. 4.48 kPa) to a 95% confidence level, with significant variability in elasticity of DM compared to NDM adipose tissue. Histologic and chemical measures of fibrosis revealed increased hydroxyproline content in DM adipose tissue, but no difference in Sirius Red staining between DM and NDM tissues. These findings support the hypothesis that fibrosis, evidenced by increased elastic modulus, is enhanced in DM adipose tissue, and suggest that measures of tissue mechanics may better resolve disease-specific differences in adipose tissue fibrosis compared with histologic measures. These data demonstrate the power of AFM nanoindentation to probe tissue mechanics, and delineate the impact of metabolic disease on the mechanical properties of adipose tissue.
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Affiliation(s)
- J K Wenderott
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60201, USA
| | - Carmen G Flesher
- Department of Surgery, Section of General Surgery, University of Michigan Medical School, 2210 Taubman Center-5343, 1500 E. Medical Center Drive, Ann Arbor, MI, 48109-5343, USA
| | - Nicki A Baker
- Department of Surgery, Section of General Surgery, University of Michigan Medical School, 2210 Taubman Center-5343, 1500 E. Medical Center Drive, Ann Arbor, MI, 48109-5343, USA
| | - Christopher K Neeley
- Department of Surgery, Section of General Surgery, University of Michigan Medical School, 2210 Taubman Center-5343, 1500 E. Medical Center Drive, Ann Arbor, MI, 48109-5343, USA
| | - Oliver A Varban
- Department of Surgery, Section of General Surgery, University of Michigan Medical School, 2210 Taubman Center-5343, 1500 E. Medical Center Drive, Ann Arbor, MI, 48109-5343, USA
| | - Carey N Lumeng
- Graduate Program in Immunology, University of Michigan, Ann Arbor, MI, 48109, USA
- Graduate Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Lutfiyya N Muhammad
- Division of Biostatistics, Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, USA
| | - Chen Yeh
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60201, USA
| | - Peter F Green
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, USA.
- National Renewable Energy Laboratory, Golden, CO, 80401, USA.
| | - Robert W O'Rourke
- Department of Surgery, Section of General Surgery, University of Michigan Medical School, 2210 Taubman Center-5343, 1500 E. Medical Center Drive, Ann Arbor, MI, 48109-5343, USA.
- Department of Surgery, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, MI, 48109, USA.
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7
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Chen PS, Chiu WT, Hsu PL, Lin SC, Peng IC, Wang CY, Tsai SJ. Pathophysiological implications of hypoxia in human diseases. J Biomed Sci 2020; 27:63. [PMID: 32389123 PMCID: PMC7212687 DOI: 10.1186/s12929-020-00658-7] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 05/06/2020] [Indexed: 12/11/2022] Open
Abstract
Oxygen is essentially required by most eukaryotic organisms as a scavenger to remove harmful electron and hydrogen ions or as a critical substrate to ensure the proper execution of enzymatic reactions. All nucleated cells can sense oxygen concentration and respond to reduced oxygen availability (hypoxia). When oxygen delivery is disrupted or reduced, the organisms will develop numerous adaptive mechanisms to facilitate cells survived in the hypoxic condition. Normally, such hypoxic response will cease when oxygen level is restored. However, the situation becomes complicated if hypoxic stress persists (chronic hypoxia) or cyclic normoxia-hypoxia phenomenon occurs (intermittent hypoxia). A series of chain reaction-like gene expression cascade, termed hypoxia-mediated gene regulatory network, will be initiated under such prolonged or intermittent hypoxic conditions and subsequently leads to alteration of cellular function and/or behaviors. As a result, irreversible processes occur that may cause physiological disorder or even pathological consequences. A growing body of evidence implicates that hypoxia plays critical roles in the pathogenesis of major causes of mortality including cancer, myocardial ischemia, metabolic diseases, and chronic heart and kidney diseases, and in reproductive diseases such as preeclampsia and endometriosis. This review article will summarize current understandings regarding the molecular mechanism of hypoxia in these common and important diseases.
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Affiliation(s)
- Pai-Sheng Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 University Road, Tainan, 70101, Taiwan, Republic of China.,Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, 1 University Road, Tainan, 70101, Taiwan, Republic of China
| | - Wen-Tai Chiu
- Department of Biomedical Engineering, College of Engineering, National Cheng Kung University, 1 University Road, Tainan, 70101, Taiwan, Republic of China
| | - Pei-Ling Hsu
- Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Road, Tainan, 70101, Taiwan, Republic of China
| | - Shih-Chieh Lin
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 University Road, Tainan, 70101, Taiwan, Republic of China
| | - I-Chen Peng
- Department of Life Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, 1 University Road, Tainan, 70101, Taiwan, Republic of China
| | - Chia-Yih Wang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 University Road, Tainan, 70101, Taiwan, Republic of China.,Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, 1 University Road, Tainan, 70101, Taiwan, Republic of China
| | - Shaw-Jenq Tsai
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, 1 University Road, Tainan, 70101, Taiwan, Republic of China. .,Department of Physiology, College of Medicine, National Cheng Kung University, 1 University Road, Tainan, 70101, Taiwan, Republic of China.
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8
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Glutamine Analogues Impair Cell Proliferation, the Intracellular Cycle and Metacyclogenesis in Trypanosoma cruzi. Molecules 2020; 25:molecules25071628. [PMID: 32252252 PMCID: PMC7180609 DOI: 10.3390/molecules25071628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/05/2020] [Accepted: 03/09/2020] [Indexed: 12/21/2022] Open
Abstract
Trypanosoma cruzi is the aetiologic agent of Chagas disease, which affects people in the Americas and worldwide. The parasite has a complex life cycle that alternates among mammalian hosts and insect vectors. During its life cycle, T. cruzi passes through different environments and faces nutrient shortages. It has been established that amino acids, such as proline, histidine, alanine, and glutamate, are crucial to T. cruzi survival. Recently, we described that T. cruzi can biosynthesize glutamine from glutamate and/or obtain it from the extracellular environment, and the role of glutamine in energetic metabolism and metacyclogenesis was demonstrated. In this study, we analysed the effect of glutamine analogues on the parasite life cycle. Here, we show that glutamine analogues impair cell proliferation, the developmental cycle during the infection of mammalian host cells and metacyclogenesis. Taken together, these results show that glutamine is an important metabolite for T. cruzi survival and suggest that glutamine analogues can be used as scaffolds for the development of new trypanocidal drugs. These data also reinforce the supposition that glutamine metabolism is an unexplored possible therapeutic target.
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9
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Gaborit B, Sengenes C, Ancel P, Jacquier A, Dutour A. Role of Epicardial Adipose Tissue in Health and Disease: A Matter of Fat? Compr Physiol 2017. [PMID: 28640452 DOI: 10.1002/cphy.c160034] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Epicardial adipose tissue (EAT) is a small but very biologically active ectopic fat depot that surrounds the heart. Given its rapid metabolism, thermogenic capacity, unique transcriptome, secretory profile, and simply measurability, epicardial fat has drawn increasing attention among researchers attempting to elucidate its putative role in health and cardiovascular diseases. The cellular crosstalk between epicardial adipocytes and cells of the vascular wall or myocytes is high and suggests a local role for this tissue. The balance between protective and proinflammatory/profibrotic cytokines, chemokines, and adipokines released by EAT seem to be a key element in atherogenesis and could represent a future therapeutic target. EAT amount has been found to predict clinical coronary outcomes. EAT can also modulate cardiac structure and function. Its amount has been associated with atrial fibrillation, coronary artery disease, and sleep apnea syndrome. Conversely, a beiging fat profile of EAT has been identified. In this review, we describe the current state of knowledge regarding the anatomy, physiology and pathophysiological role of EAT, and the factors more globally leading to ectopic fat development. We will also highlight the most recent findings on the origin of this ectopic tissue, and its association with cardiac diseases. © 2017 American Physiological Society. Compr Physiol 7:1051-1082, 2017.
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Affiliation(s)
- Bénédicte Gaborit
- NORT, Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France.,Endocrinology Metabolic Diseases, and Nutrition Department, Pole ENDO, APHM, Aix-Marseille Univ, Marseille, France
| | - Coralie Sengenes
- STROMALab, Université de Toulouse, EFS, ENVT, Inserm U1031, ERL CNRS 5311, CHU Rangueil, Toulouse, France
| | - Patricia Ancel
- NORT, Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
| | - Alexis Jacquier
- CNRS UMR 7339, Centre de Résonance Magnétique Biologique et Médicale (CRMBM), Marseille, France.,Radiology department, CHU La Timone, Marseille, France
| | - Anne Dutour
- NORT, Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France.,Endocrinology Metabolic Diseases, and Nutrition Department, Pole ENDO, APHM, Aix-Marseille Univ, Marseille, France
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10
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Baker NA, Muir LA, Washabaugh AR, Neeley CK, Chen SYP, Flesher CG, Vorwald J, Finks JF, Ghaferi AA, Mulholland MW, Varban OA, Lumeng CN, O’Rourke RW. Diabetes-Specific Regulation of Adipocyte Metabolism by the Adipose Tissue Extracellular Matrix. J Clin Endocrinol Metab 2017; 102:1032-1043. [PMID: 28359093 PMCID: PMC5460687 DOI: 10.1210/jc.2016-2915] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 12/30/2016] [Indexed: 01/15/2023]
Abstract
CONTEXT The role of the extracellular matrix (ECM) in regulating adipocyte metabolism in the context of metabolic disease is poorly defined. OBJECTIVE The objective of this study was to define the metabolic phenotype of adipocytes associated with human diabetes (DM) and the role of the ECM in regulating adipocyte metabolism. DESIGN Adipose tissues from obese patients were studied in standard 2-dimensional (2D) cell culture and an in vitro model of decellularized adipose tissue ECM repopulated with human adipocytes, and results were correlated with DM status. SETTING This study was conducted at the Academic University Medical Center and Veteran's Administration Hospital. PATIENTS Seventy patients with morbid obesity undergoing bariatric surgery were included in the study. INTERVENTIONS Visceral and subcutaneous adipose tissues were collected at the time of bariatric surgery. OUTCOME MEASURES This study used metabolic assays for glucose uptake, lipolysis, and lipogenesis in adipocytes in 2D cell culture and 3-dimensional ECM culture. RESULTS Adipocytes from subjects with DM manifest decreased glucose uptake and decreased lipolysis in 2D culture. ECM supports differentiation of mature adipocytes and recapitulates DM-specific differences in adipocyte metabolism observed in 2D culture. ECM from subjects without DM partially rescues glucose uptake and lipolytic defects in adipocytes from subjects with DM, whereas ECM from subjects with DM impairs glucose uptake in adipocytes from subjects without DM. CONCLUSIONS DM is associated with adipocyte metabolic dysfunction. The ECM regulates adipocyte metabolism. Nondiabetic ECM rescues metabolic dysfunction in DM adipocytes, whereas DM ECM imparts features of metabolic dysfunction to nondiabetic adipocytes. These findings suggest the ECM as a target for manipulating adipose tissue metabolism.
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Affiliation(s)
| | | | | | | | | | - Carmen G. Flesher
- Undergraduate Research Opportunity Program, University of Michigan, Ann Arbor, Michigan 48109; and
| | - John Vorwald
- Undergraduate Research Opportunity Program, University of Michigan, Ann Arbor, Michigan 48109; and
| | | | - Amir A. Ghaferi
- Department of Surgery,
- Department of Surgery, Ann Arbor Veteran’s Administration Hospital, Ann Arbor, Michigan 48109
| | | | | | - Carey N. Lumeng
- Department of Pediatrics and Communicable Diseases,
- Graduate Program in Immunology, and
- Graduate Program in Cellular and Molecular Biology, University of Michigan Medical School, Ann Arbor, Michigan 48109;
| | - Robert W. O’Rourke
- Department of Surgery,
- Department of Surgery, Ann Arbor Veteran’s Administration Hospital, Ann Arbor, Michigan 48109
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11
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Baker NA, Muir LA, Lumeng CN, O'Rourke RW. Differentiation and Metabolic Interrogation of Human Adipocytes. Methods Mol Biol 2017; 1566:61-76. [PMID: 28244041 DOI: 10.1007/978-1-4939-6820-6_7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Adipocytes differentiated from preadipocytes provide a valuable model for the study of human adipocyte metabolism. We describe methods for isolation of human stromal vascular cells, expansion of preadipocytes, differentiation into mature adipocytes, and in vitro metabolic interrogation of adipocytes.
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Affiliation(s)
- Nicki A Baker
- Section of General Surgery, Department of Surgery, University of Michigan Medical School, 2210 Taubman Center-5343, 1500 E. Medical Center Drive, Ann Arbor, MI, USA
| | - Lindsey A Muir
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Carey N Lumeng
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Robert W O'Rourke
- Section of General Surgery, Department of Surgery, University of Michigan Medical School, 2210 Taubman Center-5343, 1500 E. Medical Center Drive, Ann Arbor, MI, USA. .,Department of Surgery, Ann Arbor Veteran's Administration Hospital, Ann Arbor, MI, USA.
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12
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Metabolic Reprogramming by Hexosamine Biosynthetic and Golgi N-Glycan Branching Pathways. Sci Rep 2016; 6:23043. [PMID: 26972830 PMCID: PMC4789752 DOI: 10.1038/srep23043] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 02/23/2016] [Indexed: 12/16/2022] Open
Abstract
De novo uridine-diphosphate-N-acetylglucosamine (UDP-GlcNAc) biosynthesis requires glucose, glutamine, acetyl-CoA and uridine, however GlcNAc salvaged from glycoconjugate turnover and dietary sources also makes a significant contribution to the intracellular pool. Herein we ask whether dietary GlcNAc regulates nutrient transport and intermediate metabolism in C57BL/6 mice by increasing UDP-GlcNAc and in turn Golgi N-glycan branching. GlcNAc added to the drinking water showed a dose-dependent increase in growth of young mice, while in mature adult mice fat and body-weight increased without affecting calorie-intake, activity, energy expenditure, or the microbiome. Oral GlcNAc increased hepatic UDP-GlcNAc and N-glycan branching on hepatic glycoproteins. Glucose homeostasis, hepatic glycogen, lipid metabolism and response to fasting were altered with GlcNAc treatment. In cultured cells GlcNAc enhanced uptake of glucose, glutamine and fatty-acids, and enhanced lipid synthesis, while inhibition of Golgi N-glycan branching blocked GlcNAc-dependent lipid accumulation. The N-acetylglucosaminyltransferase enzymes of the N-glycan branching pathway (Mgat1,2,4,5) display multistep ultrasensitivity to UDP-GlcNAc, as well as branching-dependent compensation. Indeed, oral GlcNAc rescued fat accumulation in lean Mgat5−/− mice and in cultured Mgat5−/− hepatocytes, consistent with N-glycan branching compensation. Our results suggest GlcNAc reprograms cellular metabolism by enhancing nutrient uptake and lipid storage through the UDP-GlcNAc supply to N-glycan branching pathway.
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Schöttl T, Kappler L, Fromme T, Klingenspor M. Limited OXPHOS capacity in white adipocytes is a hallmark of obesity in laboratory mice irrespective of the glucose tolerance status. Mol Metab 2015; 4:631-42. [PMID: 26413469 PMCID: PMC4563017 DOI: 10.1016/j.molmet.2015.07.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 07/03/2015] [Accepted: 07/07/2015] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Several human and rodent obesity studies speculate on a causal link between altered white adipocyte mitochondria in the obese state and changes in glucose homeostasis. We here aimed to dissect whether alterations in white adipocyte mitochondrial respiratory function are a specific phenomenon of obesity or impaired glucose tolerance or both. METHODS Mature white adipocytes were purified from posterior subcutaneous and intraabdominal epididymal fat of four murine obesity models characterized by either impaired or normal oral glucose tolerance. Bioenergetic profiles, including basal, leak, and maximal respiration, were generated using high-resolution respirometry. Cell respiratory control ratios were calculated to evaluate mitochondrial respiratory function. RESULTS Maximal respiration capacity and cell respiratory control ratios were diminished in white adipocytes of each of the four murine obesity models, both in the absence and the presence of impaired glucose tolerance. Limitation was more pronounced in adipocytes of intraabdominal versus subcutaneous fat. CONCLUSION Reduced mitochondrial respiratory capacity in white adipocytes is a hallmark of murine obesity irrespective of the glucose tolerance status. Impaired respiratory capacity in white adipocytes solely is not sufficient for the development of systemic glucose intolerance.
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Affiliation(s)
| | | | | | - Martin Klingenspor
- Molecular Nutritional Medicine, Technische Universität München, Else Kröner Fresenius Center for Nutritional Medicine, Freising, Germany
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Yilmaz C, Ravikumar P, Gyawali D, Iyer R, Unger RH, Hsia CCW. Alveolar-capillary adaptation to chronic hypoxia in the fatty lung. Acta Physiol (Oxf) 2015; 213:933-46. [PMID: 25363080 DOI: 10.1111/apha.12419] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/17/2014] [Accepted: 10/26/2014] [Indexed: 12/18/2022]
Abstract
AIM Obese diabetic (ZDF fa/fa) rats with genetic leptin resistance suffer chronic lipotoxicity associated with age-related lung restriction and abnormal alveolar ultrastructure. We hypothesized that these abnormalities impair adaptation to ambient hypoxia. METHODS Male fa/fa and lean (+/+) ZDF rats (4-months old) were exposed to 21 or 13% O2 for 3 weeks. Lung function was measured under anaesthesia. Lung tissue was assayed for DNA damage and ultrastructure measured by morphometry. RESULTS In normoxia, lung volume, compliance and diffusing capacity were lower, while blood flow was higher in fa/fa than +/+ rats. In hypoxia, fa/fa animals lost more weight, circulating hematocrit rose higher, and lung volume failed to increase compared to +/+. In fa/fa, the hypoxia-induced increase in post-mortem lung volume was attenuated (19%) vs. +/+ (39%). Alveolar ducts were 35% smaller in normoxia but enlarged twofold more in hypoxia compared to +/+. Hypoxia induced broad increases (90-100%) in the volumes and surface areas of alveolar septal components in +/+ lungs; these increases were moderately attenuated in fa/fa lungs (58-75%), especially that of type II epithelium volume (16 vs. 61% in +/+). In fa/fa compared to +/+ lungs, oxidative DNA damage was greater with increased hypoxia induced efflux of alveolar macrophages. Harmonic mean thickness of the diffusion barrier was higher, indicating higher structural resistance to gas transfer. CONCLUSION Chronic lipotoxicity impaired hypoxia-induced lung expansion and compensatory alveolar growth with disproportionate effect on resident alveolar progenitor cells. The moderate structural impairment was offset by physiological adaptation primarily via a higher hematocrit.
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Affiliation(s)
- C. Yilmaz
- Pulmonary and Critical Care Medicine; Department of Internal Medicine; University of Texas Southwestern Medical Center; Dallas TX USA
| | - P. Ravikumar
- Pulmonary and Critical Care Medicine; Department of Internal Medicine; University of Texas Southwestern Medical Center; Dallas TX USA
| | - D. Gyawali
- Pulmonary and Critical Care Medicine; Department of Internal Medicine; University of Texas Southwestern Medical Center; Dallas TX USA
| | - R. Iyer
- Pulmonary and Critical Care Medicine; Department of Internal Medicine; University of Texas Southwestern Medical Center; Dallas TX USA
| | - R. H. Unger
- Touchstone Diabetes Center; Department of Internal Medicine; University of Texas Southwestern Medical Center; Dallas TX USA
| | - C. C. W. Hsia
- Pulmonary and Critical Care Medicine; Department of Internal Medicine; University of Texas Southwestern Medical Center; Dallas TX USA
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Varlamov O, Chu M, Cornea A, Sampath H, Roberts CT. Cell-autonomous heterogeneity of nutrient uptake in white adipose tissue of rhesus macaques. Endocrinology 2015; 156:80-9. [PMID: 25356825 PMCID: PMC4272393 DOI: 10.1210/en.2014-1699] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Phenotypic diversity may play an adaptive role by providing graded biological responses to fluctuations in environmental stimuli. We used single-cell imaging of the metabolizable fluorescent fatty acid analog 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-C12 and fluorescent 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose (2-NBDG) to explore cellular heterogeneity in nutrient uptake in white adipose tissue (WAT) explants of rhesus macaques. Surprisingly, WAT displayed a striking cell size-independent mosaic pattern, in that adjacent adipocytes varied with respect to insulin-stimulated BODIPY-C12 and 2-NBDG uptake. Relative free fatty acid (FFA) transport activity correlated with the cellular levels of FFA transporter protein-1 and the scavenger receptor CD36 in individual adipocytes. In vitro incubation of WAT explants for 24 hours caused partial desynchronization of cellular responses, suggesting that adipocytes may slowly alter their differential nutrient uptake activity. In vitro-differentiated human adipocytes also exhibited a mosaic pattern of BODIPY-C12 uptake. WAT from animals containing a homogeneous population of large adipocytes was nonmosaic, in that every adipocyte exhibited a similar level of BODIPY-C12 fluorescence, suggesting that the development of obesity is associated with the loss of heterogeneity in WAT. Hence, for the first time, we demonstrate an intrinsic heterogeneity in FFA and glucose transport activity in WAT.
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Affiliation(s)
- Oleg Varlamov
- Divisions of Diabetes, Obesity, and Metabolism and Developmental and Reproductive Science (O.V., C.T.R.), and Division of Neuroscience (A.C.), Oregon National Primate Research Center, Beaverton, Oregon 97006; and Division of Endocrinology, Diabetes, and Clinical Nutrition, Department of Medicine (M.C., C.T.R.) and Center for Research Occupational and Environmental Toxicology (H.S.), Oregon Health and Science University, Portland, Oregon 97239
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Trayhurn P, Alomar SY. Oxygen deprivation and the cellular response to hypoxia in adipocytes - perspectives on white and brown adipose tissues in obesity. Front Endocrinol (Lausanne) 2015; 6:19. [PMID: 25745415 PMCID: PMC4333869 DOI: 10.3389/fendo.2015.00019] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 02/02/2015] [Indexed: 12/17/2022] Open
Abstract
Relative hypoxia has been shown to develop in white adipose tissue depots of different types of obese mouse (genetic, dietary), and this leads to substantial changes in white adipocyte function. These changes include increased production of inflammation-related adipokines (such as IL-6, leptin, Angptl4, and VEGF), an increase in glucose utilization and lactate production, and the induction of fibrosis and insulin resistance. Whether hypoxia also occurs in brown adipose tissue depots in obesity has been little considered. However, a recent study has reported low pO2 in brown fat of obese mice, this involving mitochondrial loss and dysfunction. We suggest that obesity-linked hypoxia may lead to similar alterations in brown adipocytes as in white fat cells - particularly changes in adipokine production, increased glucose uptake and lactate release, and insulin resistance. This would be expected to compromise thermogenic activity and the role of brown fat in glucose homeostasis and triglyceride clearance, underpinning the development of the metabolic syndrome. Hypoxia-induced augmentation of lactate production may also stimulate the "browning" of white fat depots through recruitment of UCP1 and the development of brite adipocytes.
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Affiliation(s)
- Paul Trayhurn
- Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham, UK
- College of Science, King Saud University, Riyadh, Saudi Arabia
- Obesity Biology Unit, Institute of Ageing and Chronic Diseases, University of Liverpool, Liverpool, UK
- *Correspondence: Paul Trayhurn, Clore Laboratory, Buckingham Institute for Translational Medicine, University of Buckingham, Hunter Street, Buckingham MK18 1EG, UK e-mail:
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Abstract
Hypoxia develops in white adipose tissue in obese mice, resulting in changes in adipocyte function that may underpin the dysregulation that leads to obesity-associated disorders. Whether hypoxia occurs in adipose tissue in human obesity is unclear, with recent studies contradicting earlier reports that this was the case. Adipocytes, both murine and human, exhibit extensive functional changes in culture in response to hypoxia, which alters the expression of up to 1,300 genes. These include genes encoding key adipokines such as leptin, interleukin (IL)-6, vascular endothelial growth factor (VEGF), and matrix metalloproteinase-2 (MMP-2), which are upregulated, and adiponectin, which is downregulated. Hypoxia also inhibits the expression of genes linked to oxidative metabolism while stimulating the expression of genes associated with glycolysis. Glucose uptake and lactate release by adipocytes are both stimulated by hypoxia, and insulin sensitivity falls. Preadipocytes and macrophages in adipose tissue also respond to hypoxia. The hypoxia-signaling pathway may provide a new target for the treatment of obesity-associated disorders.
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Affiliation(s)
- Paul Trayhurn
- Obesity Biology Research Unit, Institute of Ageing and Chronic Diseases, University of Liverpool, Liverpool L69 3GA United Kingdom, and Clore Laboratory, University of Buckingham, Buckingham MK18 1EG, United Kingdom;
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