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Civelek E, Ozen G. The biological actions of prostanoids in adipose tissue in physiological and pathophysiological conditions. Prostaglandins Leukot Essent Fatty Acids 2022; 186:102508. [PMID: 36270150 DOI: 10.1016/j.plefa.2022.102508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/29/2022] [Accepted: 10/06/2022] [Indexed: 12/29/2022]
Abstract
Adipose tissue has been established as an endocrine organ that plays an important role in maintaining metabolic homeostasis. Adipose tissue releases several bioactive molecules called adipokines. Inflammation, dysregulation of adipokine synthesis, and secretion are observed in obesity and related diseases and cause adipose tissue dysfunction. Prostanoids, belonging to the eicosanoid family of lipid mediators, can be synthesized in adipose tissue and play a critical role in adipose tissue biology. In this review, we summarized the current knowledge regarding the interaction of prostanoids with adipokines, the expression of prostanoid receptors, and prostanoid synthase enzymes in adipose tissues in health and disease. Furthermore, the involvement of prostanoids in the physiological function or dysfunction of adipose tissue including inflammation, lipolysis, adipogenesis, thermogenesis, browning of adipocytes, and vascular tone regulation was also discussed by examining studies using pharmacological approaches or genetically modified animals for prostanoid receptors/synthase enzymes. Overall, the present review provides a perspective on the evidence from literature regarding the biological effects of prostanoids in adipose tissue. Among prostanoids, prostaglandin E2 (PGE2) is prominent in regards to its substantial role in both adipose tissue physiology and pathophysiology. Targeting prostanoids may serve as a potential therapeutic strategy for preventing or treating obesity and related diseases.
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Affiliation(s)
- Erkan Civelek
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey
| | - Gulsev Ozen
- Department of Pharmacology, Faculty of Pharmacy, Istanbul University, Istanbul, Turkey.
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2
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Mediator production and severity of aspirin-induced respiratory reactions: Impact of sampling site and body mass index. J Allergy Clin Immunol 2022; 150:170-177.e6. [PMID: 35026207 DOI: 10.1016/j.jaci.2021.12.787] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/23/2021] [Accepted: 12/29/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND Patients with aspirin-exacerbated respiratory disease can experience severe reactions during aspirin challenge that are associated with high levels of mast cell mediators. The tissue source and clinical factors contributing to systemic mediator levels are unknown. OBJECTIVE To determine the concordance between respiratory tract and systemic inflammatory mediator levels and identify clinical factors associated with these mediators. METHODS We performed an oral aspirin challenge in 30 subjects with aspirin-exacerbated respiratory disease. Respiratory symptoms and function, nasal mucosal fluid, blood, and urine were collected at baseline, at the onset of a respiratory reaction and over a 3-hour observation period. Changes in nasal and systemic mediator levels were compared. RESULTS Neither tryptase nor leukotriene E4 levels in nasal fluid correlated with serum tryptase or urinary leukotriene E4 at baseline or during reactions. We observed no association between the baseline or aspirin-induced change in nasal versus urinary leukotriene E4 and serum tryptase levels. Body mass index inversely correlated with baseline and aspirin-induced urinary leukotriene E4, prostaglandin D2 metabolite, and serum tryptase levels, as well as with aspirin-induced symptoms and respiratory function, but not with nasal mediators. CONCLUSION The levels of nasal and systemic aspirin-induced mast cell products are discordant in aspirin-exacerbated respiratory disease. Systemically detected levels are likely derived from mast cells outside of the sinonasal cavity and do not accurately reflect upper respiratory tract production. Increased body mass index decreases systemic mast cell mediator production and reaction severity, supporting a contribution of metabolic regulation in aspirin-induced systemic reactions.
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3
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Luk C, Haywood NJ, Bridge KI, Kearney MT. Paracrine Role of the Endothelium in Metabolic Homeostasis in Health and Nutrient Excess. Front Cardiovasc Med 2022; 9:882923. [PMID: 35557517 PMCID: PMC9086712 DOI: 10.3389/fcvm.2022.882923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 04/04/2022] [Indexed: 02/02/2023] Open
Abstract
The vascular endothelium traditionally viewed as a simple physical barrier between the circulation and tissue is now well-established as a key organ mediating whole organism homeostasis by release of a portfolio of anti-inflammatory and pro-inflammatory vasoactive molecules. Healthy endothelium releases anti-inflammatory signaling molecules such as nitric oxide and prostacyclin; in contrast, diseased endothelium secretes pro-inflammatory signals such as reactive oxygen species, endothelin-1 and tumor necrosis factor-alpha (TNFα). Endothelial dysfunction, which has now been identified as a hallmark of different components of the cardiometabolic syndrome including obesity, type 2 diabetes and hypertension, initiates and drives the progression of tissue damage in these disorders. Recently it has become apparent that, in addition to vasoactive molecules, the vascular endothelium has the potential to secrete a diverse range of small molecules and proteins mediating metabolic processes in adipose tissue (AT), liver, skeletal muscle and the pancreas. AT plays a pivotal role in orchestrating whole-body energy homeostasis and AT dysfunction, characterized by local and systemic inflammation, is central to the metabolic complications of obesity. Thus, understanding and targeting the crosstalk between the endothelium and AT may generate novel therapeutic opportunities for the cardiometabolic syndrome. Here, we provide an overview of the role of the endothelial secretome in controlling the function of AT. The endothelial-derived metabolic regulatory factors are grouped and discussed based on their physical properties and their downstream signaling effects. In addition, we focus on the therapeutic potential of these regulatory factors in treating cardiometabolic syndrome, and discuss areas of future study of potential translatable and clinical significance. The vascular endothelium is emerging as an important paracrine/endocrine organ that secretes regulatory factors in response to nutritional and environmental cues. Endothelial dysfunction may result in imbalanced secretion of these regulatory factors and contribute to the progression of AT and whole body metabolic dysfunction. As the vascular endothelium is the first responder to local nutritional changes and adipocyte-derived signals, future work elucidating the changes in the endothelial secretome is crucial to improve our understanding of the pathophysiology of cardiometabolic disease, and in aiding our development of new therapeutic strategies to treat and prevent cardiometabolic syndrome.
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Affiliation(s)
- Cheukyau Luk
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Natalie J Haywood
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Katherine I Bridge
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
| | - Mark T Kearney
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
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4
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Obesity-induced changes in human islet G protein-coupled receptor expression: Implications for metabolic regulation. Pharmacol Ther 2021; 228:107928. [PMID: 34174278 DOI: 10.1016/j.pharmthera.2021.107928] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/10/2021] [Accepted: 05/18/2021] [Indexed: 12/22/2022]
Abstract
G protein-coupled receptors (GPCRs) are a large family of cell surface receptors that are the targets for many different classes of pharmacotherapy. The islets of Langerhans are central to appropriate glucose homeostasis through their secretion of insulin, and islet function can be modified by ligands acting at the large number of GPCRs that islets express. The human islet GPCRome is not a static entity, but one that is altered under pathophysiological conditions and, in this review, we have compared expression of GPCR mRNAs in human islets obtained from normal weight range donors, and those with a weight range classified as obese. We have also considered the likely outcomes on islet function that the altered GPCR expression status confers and the possible impact that adipokines, secreted from expanded fat depots, could have at those GPCRs showing altered expression in obesity.
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Onogi Y, Khalil AEMM, Ussar S. Identification and characterization of adipose surface epitopes. Biochem J 2020; 477:2509-2541. [PMID: 32648930 PMCID: PMC7360119 DOI: 10.1042/bcj20190462] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 06/11/2020] [Accepted: 06/12/2020] [Indexed: 12/14/2022]
Abstract
Adipose tissue is a central regulator of metabolism and an important pharmacological target to treat the metabolic consequences of obesity, such as insulin resistance and dyslipidemia. Among the various cellular compartments, the adipocyte cell surface is especially appealing as a drug target as it contains various proteins that when activated or inhibited promote adipocyte health, change its endocrine function and eventually maintain or restore whole-body insulin sensitivity. In addition, cell surface proteins are readily accessible by various drug classes. However, targeting individual cell surface proteins in adipocytes has been difficult due to important functions of these proteins outside adipose tissue, raising various safety concerns. Thus, one of the biggest challenges is the lack of adipose selective surface proteins and/or targeting reagents. Here, we discuss several receptor families with an important function in adipogenesis and mature adipocytes to highlight the complexity at the cell surface and illustrate the problems with identifying adipose selective proteins. We then discuss that, while no unique adipocyte surface protein might exist, how splicing, posttranslational modifications as well as protein/protein interactions can create enormous diversity at the cell surface that vastly expands the space of potentially unique epitopes and how these selective epitopes can be identified and targeted.
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Affiliation(s)
- Yasuhiro Onogi
- RG Adipocytes and Metabolism, Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764 Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Ahmed Elagamy Mohamed Mahmoud Khalil
- RG Adipocytes and Metabolism, Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764 Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Siegfried Ussar
- RG Adipocytes and Metabolism, Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764 Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
- Department of Medicine, Technische Universität München, Munich, Germany
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6
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Nava E, Llorens S. The Local Regulation of Vascular Function: From an Inside-Outside to an Outside-Inside Model. Front Physiol 2019; 10:729. [PMID: 31244683 PMCID: PMC6581701 DOI: 10.3389/fphys.2019.00729] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/27/2019] [Indexed: 01/22/2023] Open
Abstract
Our understanding of the regulation of vascular function, specifically that of vasomotion, has evolved dramatically over the past few decades. The classic conception of a vascular system solely regulated by circulating hormones and sympathetic innervation gave way to a vision of a local regulation. Initially by the so-called, autacoids like prostacyclin, which represented the first endothelium-derived paracrine regulator of smooth muscle. This was the prelude of the EDRF-nitric oxide age that has occupied vascular scientists for nearly 30 years. Endothelial cells revealed to have the ability to generate numerous mediators besides prostacyclin and nitric oxide (NO). The need to classify these substances led to the coining of the terms: endothelium-derived relaxing, hyperpolarizing and contracting factors, which included various prostaglandins, thromboxane A2, endothelin, as well numerous candidates for the hyperpolarizing factor. The opposite layer of the vascular wall, the adventitia, eventually and for a quite short period of time, enjoyed the attention of some vascular physiologists. Adventitial fibroblasts were recognized as paracrine cells to the smooth muscle because of their ability to produce some substances such as superoxide. Remarkably, this took place before our awareness of the functional potential of another adventitial cell, the adipocyte. Possibly, because the perivascular adipose tissue (PVAT) was systematically removed during the experiments as considered a non-vascular artifact tissue, it took quite long to be considered a major source of paracrine substances. These are now being integrated in the vast pool of mediators synthesized by adipocytes, known as adipokines. They include hormones involved in metabolic regulation, like leptin or adiponectin; classic vascular mediators like NO, angiotensin II or catecholamines; and inflammatory mediators or adipocytokines. The first substance studied was an anti-contractile factor named adipose-derived relaxing factor of uncertain chemical nature but possibly, some of the relaxing mediators mentioned above are behind this factor. This manuscript intends to review the vascular regulation from the point of view of the paracrine control exerted by the cells present in the vascular environment, namely, endothelial, adventitial, adipocyte and vascular stromal cells.
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Affiliation(s)
- Eduardo Nava
- Department of Medical Sciences, Faculty of Medicine of Albacete, Centro Regional de Investigaciones Biomédicas (CRIB), University of Castilla-La Mancha, Albacete, Spain
| | - Silvia Llorens
- Department of Medical Sciences, Faculty of Medicine of Albacete, Centro Regional de Investigaciones Biomédicas (CRIB), University of Castilla-La Mancha, Albacete, Spain
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Priyadarshini S, Pradhan B, Aich P. Role of murine macrophage in temporal regulation of cortisol- and serotonin-induced adipogenesis in pre-adipocytes when grown together. Biol Open 2018; 7:bio.034629. [PMID: 30082376 PMCID: PMC6124570 DOI: 10.1242/bio.034629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Regulation of adipogenesis, the root cause for obesity, is very poorly understood. However, studies have presented evidence of immuno-metabolic regulation of adipose tissue during periods of chronic psychological stress, leading to adverse conditions related to stress manifestation, including visceral obesity and atherosclerosis. Despite pronounced association of hormonal markers of stress with dys-regulated metabolic states, the contributing signalling events are yet to be established. It is apparent that to understand contributing signalling events we need a model. Although an in vivo model is preferred, it is difficult to establish. The current report, therefore, presents an in vitro model system for the simulation of adipose tissue in a chronic stress micro-environment by growing pre-adipocytes with macrophages in the presence and absence of stress hormones. In this report, effects of cortisol and serotonin on the kinetics of immune and metabolic changes in adipocytes and macrophage (alone and co-cultured) was studied through whole genome transcriptome profiling. A transition from pro- to anti-inflammatory response in the immune profile of pre-adipocytes, with increasing time in co-culture with macrophages, was observed. This transition was reversed by stress hormones cortisol and/or serotonin. Summary: Stress-induced obesity is poorly understood in vivo at the molecular level. The current report established a novel molecular basis of adipogenesis in vitro.
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Affiliation(s)
- Sushri Priyadarshini
- School of Biological Sciences, National Institute of Science Education and Research (NISER), HBNI, PO- Bhimpur-Padanpur, Via- Jatni, District:- Khurda, 752050, Odisha, India
| | - Biswaranjan Pradhan
- School of Biological Sciences, National Institute of Science Education and Research (NISER), HBNI, PO- Bhimpur-Padanpur, Via- Jatni, District:- Khurda, 752050, Odisha, India
| | - Palok Aich
- School of Biological Sciences, National Institute of Science Education and Research (NISER), HBNI, PO- Bhimpur-Padanpur, Via- Jatni, District:- Khurda, 752050, Odisha, India
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Human GIP(3-30)NH 2 inhibits G protein-dependent as well as G protein-independent signaling and is selective for the GIP receptor with high-affinity binding to primate but not rodent GIP receptors. Biochem Pharmacol 2018; 150:97-107. [PMID: 29378179 DOI: 10.1016/j.bcp.2018.01.040] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 01/22/2018] [Indexed: 12/21/2022]
Abstract
GIP(3-30)NH2 is a high affinity antagonist of the GIP receptor (GIPR) in humans inhibiting insulin secretion via G protein-dependent pathways. However, its ability to inhibit G protein-independent signaling is unknown. Here we determine its action on arrestin-recruitment and receptor internalization in recombinant cells. As GIP is adipogenic, we evaluate the inhibitory actions of GIP(3-30)NH2 in human adipocytes. Finally, we determine the receptor selectivity of GIP(3-30)NH2 among other human and animal GPCRs. cAMP accumulation and β-arrestin 1 and 2 recruitment were studied in transiently transfected HEK293 cells and real-time internalization in transiently transfected HEK293A and in HEK293A β-arrestin 1 and 2 knockout cells. Furthermore, human subcutaneous adipocytes were assessed for cAMP accumulation following ligand stimulation. Competition binding was examined in transiently transfected COS-7 cells using human 125I-GIP(3-30)NH2. The selectivity of human GIP(3-30)NH2 was examined by testing for agonistic and antagonistic properties on 62 human GPCRs. Human GIP(3-30)NH2 inhibited GIP(1-42)-induced cAMP and β-arrestin 1 and 2 recruitment on the human GIPR and Schild plot analysis showed competitive antagonism with a pA2 and Hill slope of 16.8 nM and 1.11 ± 0.02 in cAMP, 10.6 nM and 1.15 ± 0.05 in β-arrestin 1 recruitment, and 10.2 nM and 1.06 ± 0.05 in β-arrestin 2 recruitment. Efficient internalization of the GIPR was dependent on the presence of either β-arrestin 1 or 2. Moreover, GIP(3-30)NH2 inhibited GIP(1-42)-induced internalization in a concentration-dependent manner and notably also inhibited GIP-mediated signaling in human subcutaneous adipocytes. Finally, the antagonist was established as GIPR selective among 62 human GPCRs being species-specific with high affinity binding to the human and non-human primate (Macaca fascicularis) GIPRs, and low affinity binding to the rat and mouse GIPRs (Kd values of 2.0, 2.5, 31.6 and 100 nM, respectively). In conclusion, human GIP(3-30)NH2 is a selective and species-specific GIPR antagonist with broad inhibition of signaling and internalization in transfected cells as well as in human adipocytes.
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9
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Nava E, Llorens S. The paracrine control of vascular motion. A historical perspective. Pharmacol Res 2016; 113:125-145. [PMID: 27530204 DOI: 10.1016/j.phrs.2016.08.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/13/2016] [Accepted: 08/01/2016] [Indexed: 12/26/2022]
Abstract
During the last quarter of the past century, the leading role the endocrine and nervous systems had on the regulation of vasomotion, shifted towards a more paracrine-based regulation. This begun with the recognition of endothelial cells as active players of vascular control, when the vessel's intimal layer was identified as the main source of prostacyclin and was followed by the discovery of an endothelium-derived smooth muscle cell relaxing factor (EDRF). The new position acquired by endothelial cells prompted the discovery of other endothelium-derived regulatory products: vasoconstrictors, generally known as EDCFs, endothelin, and other vasodilators with hyperpolarizing properties (EDHFs). While this research was taking place, a quest for the discovery of the nature of EDRF carried back to a research line commenced a decade earlier: the recently found intracellular messenger cGMP and nitrovasodilators. Both were smooth muscle relaxants and appeared to interact in a hormonal fashion. Prejudice against an unconventional gaseous molecule delayed the acceptance that EDRF was nitric oxide (NO). When this happened, a new era of research that exceeded the vascular field commenced. The discovery of the pathway for NO synthesis from L-arginine involved the clever assembling of numerous unrelated observations of different areas of knowledge. The last ten years of research on the paracrine regulation of the vascular wall has shifted to perivascular fat (PVAT), which is beginning to be regarded as the fourth layer of the vascular wall. Starting with the discovery of an adipose-derived relaxing substance (ADRF), the role that different adipokines have on the paracrine control of vasomotion is now filling the research activity of many vascular pharmacology labs, and surprising interactions between the endothelium, PVAT and smooth muscle are being unveiled.
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Affiliation(s)
- Eduardo Nava
- Area of Physiology, Department of Medical Sciences, University of Castilla-La Mancha, School of Medicine and Regional Centre for Biomedical Research (CRIB), Albacete, Spain.
| | - Silvia Llorens
- Area of Physiology, Department of Medical Sciences, University of Castilla-La Mancha, School of Medicine and Regional Centre for Biomedical Research (CRIB), Albacete, Spain
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10
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Ceddia RP, Lee D, Maulis MF, Carboneau BA, Threadgill DW, Poffenberger G, Milne G, Boyd KL, Powers AC, McGuinness OP, Gannon M, Breyer RM. The PGE2 EP3 Receptor Regulates Diet-Induced Adiposity in Male Mice. Endocrinology 2016; 157:220-32. [PMID: 26485614 PMCID: PMC4701878 DOI: 10.1210/en.2015-1693] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mice carrying a targeted disruption of the prostaglandin E2 (PGE2) E-prostanoid receptor 3 (EP3) gene, Ptger3, were fed a high-fat diet (HFD), or a micronutrient matched control diet, to investigate the effects of disrupted PGE2-EP3 signaling on diabetes in a setting of diet-induced obesity. Although no differences in body weight were seen in mice fed the control diet, when fed a HFD, EP3(-/-) mice gained more weight relative to EP3(+/+) mice. Overall, EP3(-/-) mice had increased epididymal fat mass and adipocyte size; paradoxically, a relative decrease in both epididymal fat pad mass and adipocyte size was observed in the heaviest EP3(-/-) mice. The EP3(-/-) mice had increased macrophage infiltration, TNF-α, monocyte chemoattractant protein-1, IL-6 expression, and necrosis in their epididymal fat pads as compared with EP3(+/+) animals. Adipocytes isolated from EP3(+/+) or EP3(-/-) mice were assayed for the effect of PGE2-evoked inhibition of lipolysis. Adipocytes isolated from EP3(-/-) mice lacked PGE2-evoked inhibition of isoproterenol stimulated lipolysis compared with EP3(+/+). EP3(-/-) mice fed HFD had exaggerated ectopic lipid accumulation in skeletal muscle and liver, with evidence of hepatic steatosis. Both blood glucose and plasma insulin levels were similar between genotypes on a control diet, but when fed HFD, EP3(-/-) mice became hyperglycemic and hyperinsulinemic when compared with EP3(+/+) fed HFD, demonstrating a more severe insulin resistance phenotype in EP3(-/-). These results demonstrate that when fed a HFD, EP3(-/-) mice have abnormal lipid distribution, developing excessive ectopic lipid accumulation and associated insulin resistance.
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MESH Headings
- Adipose Tissue, White/immunology
- Adipose Tissue, White/metabolism
- Adipose Tissue, White/pathology
- Adiposity
- Animals
- Cell Size
- Crosses, Genetic
- Diabetes Mellitus, Type 2/etiology
- Diabetes Mellitus, Type 2/immunology
- Diet, High-Fat/adverse effects
- Insulin Resistance
- Lipid Metabolism
- Liver/immunology
- Liver/metabolism
- Liver/pathology
- Macrophage Activation
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Skeletal/immunology
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Necrosis
- Non-alcoholic Fatty Liver Disease/etiology
- Non-alcoholic Fatty Liver Disease/immunology
- Obesity/etiology
- Obesity/metabolism
- Obesity/pathology
- Obesity/physiopathology
- Panniculitis/etiology
- Panniculitis/immunology
- Receptors, Prostaglandin E, EP3 Subtype/genetics
- Receptors, Prostaglandin E, EP3 Subtype/metabolism
- Weight Gain
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Affiliation(s)
- Ryan P Ceddia
- Department of Veterans Affairs (A.C.P., M.G., R.M.B.), Tennessee Valley Health Authority, and Department of Medicine (R.M.B.), Division of Nephrology and Hypertension; Departments of Pharmacology (R.P.C., G.M., R.M.B.) and Cell and Developmental Biology (D.L., D.W.T., M.G.); Department of Medicine (M.F.M., G.P., A.C.P., M.G.), Division of Diabetes, Endocrinology, and Metabolism; and Departments of Molecular Physiology and Biophysics (B.A.C., A.C.P., O.P.G., M.G.) and Pathology, Microbiology, and Immunology (K.L.B.), Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - DaeKee Lee
- Department of Veterans Affairs (A.C.P., M.G., R.M.B.), Tennessee Valley Health Authority, and Department of Medicine (R.M.B.), Division of Nephrology and Hypertension; Departments of Pharmacology (R.P.C., G.M., R.M.B.) and Cell and Developmental Biology (D.L., D.W.T., M.G.); Department of Medicine (M.F.M., G.P., A.C.P., M.G.), Division of Diabetes, Endocrinology, and Metabolism; and Departments of Molecular Physiology and Biophysics (B.A.C., A.C.P., O.P.G., M.G.) and Pathology, Microbiology, and Immunology (K.L.B.), Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Matthew F Maulis
- Department of Veterans Affairs (A.C.P., M.G., R.M.B.), Tennessee Valley Health Authority, and Department of Medicine (R.M.B.), Division of Nephrology and Hypertension; Departments of Pharmacology (R.P.C., G.M., R.M.B.) and Cell and Developmental Biology (D.L., D.W.T., M.G.); Department of Medicine (M.F.M., G.P., A.C.P., M.G.), Division of Diabetes, Endocrinology, and Metabolism; and Departments of Molecular Physiology and Biophysics (B.A.C., A.C.P., O.P.G., M.G.) and Pathology, Microbiology, and Immunology (K.L.B.), Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Bethany A Carboneau
- Department of Veterans Affairs (A.C.P., M.G., R.M.B.), Tennessee Valley Health Authority, and Department of Medicine (R.M.B.), Division of Nephrology and Hypertension; Departments of Pharmacology (R.P.C., G.M., R.M.B.) and Cell and Developmental Biology (D.L., D.W.T., M.G.); Department of Medicine (M.F.M., G.P., A.C.P., M.G.), Division of Diabetes, Endocrinology, and Metabolism; and Departments of Molecular Physiology and Biophysics (B.A.C., A.C.P., O.P.G., M.G.) and Pathology, Microbiology, and Immunology (K.L.B.), Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - David W Threadgill
- Department of Veterans Affairs (A.C.P., M.G., R.M.B.), Tennessee Valley Health Authority, and Department of Medicine (R.M.B.), Division of Nephrology and Hypertension; Departments of Pharmacology (R.P.C., G.M., R.M.B.) and Cell and Developmental Biology (D.L., D.W.T., M.G.); Department of Medicine (M.F.M., G.P., A.C.P., M.G.), Division of Diabetes, Endocrinology, and Metabolism; and Departments of Molecular Physiology and Biophysics (B.A.C., A.C.P., O.P.G., M.G.) and Pathology, Microbiology, and Immunology (K.L.B.), Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Greg Poffenberger
- Department of Veterans Affairs (A.C.P., M.G., R.M.B.), Tennessee Valley Health Authority, and Department of Medicine (R.M.B.), Division of Nephrology and Hypertension; Departments of Pharmacology (R.P.C., G.M., R.M.B.) and Cell and Developmental Biology (D.L., D.W.T., M.G.); Department of Medicine (M.F.M., G.P., A.C.P., M.G.), Division of Diabetes, Endocrinology, and Metabolism; and Departments of Molecular Physiology and Biophysics (B.A.C., A.C.P., O.P.G., M.G.) and Pathology, Microbiology, and Immunology (K.L.B.), Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Ginger Milne
- Department of Veterans Affairs (A.C.P., M.G., R.M.B.), Tennessee Valley Health Authority, and Department of Medicine (R.M.B.), Division of Nephrology and Hypertension; Departments of Pharmacology (R.P.C., G.M., R.M.B.) and Cell and Developmental Biology (D.L., D.W.T., M.G.); Department of Medicine (M.F.M., G.P., A.C.P., M.G.), Division of Diabetes, Endocrinology, and Metabolism; and Departments of Molecular Physiology and Biophysics (B.A.C., A.C.P., O.P.G., M.G.) and Pathology, Microbiology, and Immunology (K.L.B.), Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Kelli L Boyd
- Department of Veterans Affairs (A.C.P., M.G., R.M.B.), Tennessee Valley Health Authority, and Department of Medicine (R.M.B.), Division of Nephrology and Hypertension; Departments of Pharmacology (R.P.C., G.M., R.M.B.) and Cell and Developmental Biology (D.L., D.W.T., M.G.); Department of Medicine (M.F.M., G.P., A.C.P., M.G.), Division of Diabetes, Endocrinology, and Metabolism; and Departments of Molecular Physiology and Biophysics (B.A.C., A.C.P., O.P.G., M.G.) and Pathology, Microbiology, and Immunology (K.L.B.), Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Alvin C Powers
- Department of Veterans Affairs (A.C.P., M.G., R.M.B.), Tennessee Valley Health Authority, and Department of Medicine (R.M.B.), Division of Nephrology and Hypertension; Departments of Pharmacology (R.P.C., G.M., R.M.B.) and Cell and Developmental Biology (D.L., D.W.T., M.G.); Department of Medicine (M.F.M., G.P., A.C.P., M.G.), Division of Diabetes, Endocrinology, and Metabolism; and Departments of Molecular Physiology and Biophysics (B.A.C., A.C.P., O.P.G., M.G.) and Pathology, Microbiology, and Immunology (K.L.B.), Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Owen P McGuinness
- Department of Veterans Affairs (A.C.P., M.G., R.M.B.), Tennessee Valley Health Authority, and Department of Medicine (R.M.B.), Division of Nephrology and Hypertension; Departments of Pharmacology (R.P.C., G.M., R.M.B.) and Cell and Developmental Biology (D.L., D.W.T., M.G.); Department of Medicine (M.F.M., G.P., A.C.P., M.G.), Division of Diabetes, Endocrinology, and Metabolism; and Departments of Molecular Physiology and Biophysics (B.A.C., A.C.P., O.P.G., M.G.) and Pathology, Microbiology, and Immunology (K.L.B.), Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Maureen Gannon
- Department of Veterans Affairs (A.C.P., M.G., R.M.B.), Tennessee Valley Health Authority, and Department of Medicine (R.M.B.), Division of Nephrology and Hypertension; Departments of Pharmacology (R.P.C., G.M., R.M.B.) and Cell and Developmental Biology (D.L., D.W.T., M.G.); Department of Medicine (M.F.M., G.P., A.C.P., M.G.), Division of Diabetes, Endocrinology, and Metabolism; and Departments of Molecular Physiology and Biophysics (B.A.C., A.C.P., O.P.G., M.G.) and Pathology, Microbiology, and Immunology (K.L.B.), Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Richard M Breyer
- Department of Veterans Affairs (A.C.P., M.G., R.M.B.), Tennessee Valley Health Authority, and Department of Medicine (R.M.B.), Division of Nephrology and Hypertension; Departments of Pharmacology (R.P.C., G.M., R.M.B.) and Cell and Developmental Biology (D.L., D.W.T., M.G.); Department of Medicine (M.F.M., G.P., A.C.P., M.G.), Division of Diabetes, Endocrinology, and Metabolism; and Departments of Molecular Physiology and Biophysics (B.A.C., A.C.P., O.P.G., M.G.) and Pathology, Microbiology, and Immunology (K.L.B.), Vanderbilt University Medical Center, Nashville, Tennessee 37232
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11
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Vailati Riboni M, Meier S, Priest N, Burke C, Kay J, McDougall S, Mitchell M, Walker C, Crookenden M, Heiser A, Roche J, Loor J. Adipose and liver gene expression profiles in response to treatment with a nonsteroidal antiinflammatory drug after calving in grazing dairy cows. J Dairy Sci 2015; 98:3079-85. [DOI: 10.3168/jds.2014-8579] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 01/11/2015] [Indexed: 01/16/2023]
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12
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Mendizábal Y, Llorens S, Nava E. Vasoactive effects of prostaglandins from the perivascular fat of mesenteric resistance arteries in WKY and SHROB rats. Life Sci 2013; 93:1023-32. [PMID: 24200844 DOI: 10.1016/j.lfs.2013.10.021] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 10/12/2013] [Accepted: 10/19/2013] [Indexed: 10/26/2022]
Abstract
AIMS We have studied the vasoactive role of prostaglandins derived from perivascular adipose tissue (PVAT) and their effects on endothelial function in healthy rats and rats with metabolic syndrome (SHROB). MAIN METHODS Mesenteric resistance arteries (MRA) from SHROB and control rats (WKY) were mounted on wire myographs: a) together with a sphere of naturally occurring perivascular adipose tissue (with-PVAT group), or b) dissecting all the adventitial tissue (without-PVAT group). KEY FINDINGS Endothelial function, tested by acetylcholine reactivity of SHROB arteries with PVAT, was significantly lower than that of WKY. With-PVAT arteries, especially the SHROB, showed lower responses than those without PVAT. NO synthase inhibition diminished the acetylcholine responses in every group except the with-PVAT SHROB group. Blockade of cyclooxygenase-2, PGI2-IP, TXA2-TP, or TXA2 synthase increased to different extents the arterial responses in the SHROB with-PVAT group. PVAT from both rat strains revealed cyclooxygenase-2 activity and immunoassay confirmed the release of PGE2, PGI2 and TXA2. SIGNIFICANCE Our major finding is that PVAT is a source of vasoactive prostaglandins in WKY and SHROB. We also report that the presence of visceral PVAT causes endothelial dysfunction of resistance arteries in the SHROB. The vascular responses to prostaglandins partly underlie the endothelial dysfunction of SHROB arteries.
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Affiliation(s)
- Yolanda Mendizábal
- Area of Physiology, Department of Medical Sciences, University of Castilla-La Mancha, School of Medicine and Regional Centre for Biomedical Research (CRIB), Albacete, Spain
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13
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Haplotype combinations of AdPLA gene polymorphisms associate with growth traits in Chinese cattle. Mol Biol Rep 2012; 39:7069-76. [DOI: 10.1007/s11033-012-1538-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Accepted: 01/24/2012] [Indexed: 11/26/2022]
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14
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Karastergiou K, Mohamed-Ali V. The autocrine and paracrine roles of adipokines. Mol Cell Endocrinol 2010; 318:69-78. [PMID: 19948207 DOI: 10.1016/j.mce.2009.11.011] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 11/16/2009] [Accepted: 11/23/2009] [Indexed: 12/23/2022]
Abstract
Obesity, defined by an excess of adipose tissue, is often associated with the development of various metabolic diseases. The increased and inappropriate deposition of this tissue contributes to hyperglycemia, hyperlipidemia, insulin resistance, endothelial dysfunction and chronic inflammation. Recent evidence suggests that factors expressed and secreted by the adipose tissue, adipokines, may contribute to the development of these abnormalities by mechanisms including inhibition of adipogenesis, adipocyte hypertrophy and death, immune cell infiltration and disruption of tissue metabolism. The presence of adipokine receptors in adipocytes renders these cells available to autocrine and paracrine effects of adipokines. In this review the reported local effects of adipokines on adipose tissue structure, inflammation and regulation of metabolic functions, in the face of over-nutrition and consequent obesity, are outlined. Elucidating the local regulation of white adipocyte development and function could help in the design of effective, tissue-specific therapies for obesity-associated diseases.
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Affiliation(s)
- Kalypso Karastergiou
- Adipokines and Metabolism Research Group, Centre for Clinical Pharmacology, Division of Medicine, University College London, 5 University Street, London WC1E 6JJ, UK
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15
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Wortman P, Miyazaki Y, Kalupahana NS, Kim S, Hansen-Petrik M, Saxton AM, Claycombe KJ, Voy BH, Whelan J, Moustaid-Moussa N. n3 and n6 polyunsaturated fatty acids differentially modulate prostaglandin E secretion but not markers of lipogenesis in adipocytes. Nutr Metab (Lond) 2009; 6:5. [PMID: 19159447 PMCID: PMC2646735 DOI: 10.1186/1743-7075-6-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Accepted: 01/21/2009] [Indexed: 12/27/2022] Open
Abstract
A dramatic rise in the incidence of obesity in the U.S. has accelerated the search for interventions that may impact this epidemic. One recently recognized target for such intervention is adipose tissue, which secretes a variety of bioactive substances including prostaglandins. Prostaglandin E2 (PGE2) has been shown to decrease lipolysis in adipocytes, but limited studies have explored alternative mechanisms by which PGE2 might impact obesity, such as adipogenesis or lipogenesis. Studies conducted on ApcMin/+ mice indicated that selective inhibition of the cyclooxygenase (COX)-2 enzyme led to significant reductions in fatty acid synthase (FAS) activity in adipose tissue suggesting lipogenic effects of PGE2. To further investigate whether these lipid mediators directly regulate lipogenesis, we used 3T3-L1 adipocytes to determine the impact of eicosapentaenoic acid (EPA) and celecoxib on PGE2 formation and FAS used as a lipogenic marker. Both arachidonic acid (AA) and EPA dose-dependently increased PGE secretion from adipocytes. AA was expectedly more potent and exhibiting at 150 uM dose a 5-fold increase in PGE2 secretion over EPA. Despite higher secretion of PGE by EPA and AA compared to control, neither PUFA significantly altered FAS activity. By contrast both AA and EPA significantly decreased FAS mRNA levels. Addition of celecoxib, a selective COX-2 inhibitor, significantly decreased PGE2 secretion (p < 0.05) versus control, and also significantly decreased FAS activity (p < 0.05). Unexpectedly, the combination of exogenous PGE2 and celecoxib further decreased the FAS activity compared to PGE2 alone or untreated controls. In conclusion, EPA-mediated inhibition of AA metabolism did not significantly alter FAS activity while both AA and EPA significantly decreased FAS mRNA expression. COX-2 inhibition significantly decreased PGE2 production resulting in a decrease in FAS activity and expression that was not reversed with the addition of exogenous PGE2, suggesting an additional mechanism that is independent of COX-2.
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Affiliation(s)
- Patrick Wortman
- University of Tennessee (UT), Department of Animal Science, Knoxville, TN, USA.
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16
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AdPLA ablation increases lipolysis and prevents obesity induced by high-fat feeding or leptin deficiency. Nat Med 2009; 15:159-68. [PMID: 19136964 PMCID: PMC2863116 DOI: 10.1038/nm.1904] [Citation(s) in RCA: 202] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Accepted: 11/19/2008] [Indexed: 01/04/2023]
Abstract
A main function of white adipose tissue is to release fatty acids from triacylglycerol for other tissues to use as an energy source. While endocrine regulation of lipolysis has been extensively studied, autocrine/paracrine regulation is not well understood. Here, we describe the role of AdPLA, the newly identified major adipocyte phospholipase A2, in the regulation of lipolysis and adiposity. AdPLA null mice have a markedly higher rate of lipolysis, due to increased cAMP levels arising from the marked reduction in adipose PGE2 that binds the Gαi-coupled receptor, EP3. AdPLA null mice have drastically reduced adipose tissue mass and triglyceride content, with normal adipogenesis. They also have higher energy expenditure with higher fatty acid oxidation within adipocytes. AdPLA deficient ob/ob mice remain hyperphagic but lean, with increased energy expenditure, yet have ectopic triglyceride storage and insulin resistance. AdPLA is a major regulator of adipocyte lipolysis and critical for the development of obesity.
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17
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Low-dose acetylsalicylic acid inhibits the secretion of interleukin-6 from white adipose tissue. Int J Obes (Lond) 2008; 32:1807-15. [PMID: 18982014 DOI: 10.1038/ijo.2008.190] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Chronically elevated interleukin-6 (IL-6) is implicated in obesity-associated pathologies, where a proportion of this cytokine is derived from adipose tissue. Proinflammatory prostaglandins, which regulate this cytokine elsewhere, are also produced by this tissue. OBJECTIVE To investigate whether constitutively active cyclooxygenase (COX)/prostaglandin (PG) pathway in white adipose tissue (WAT) is responsible for basal IL-6 production. DESIGN The effect of acetylsalicylic acid (ASA), an inhibitor of COX, on IL-6 was assessed in human subjects and mice. COX, downstream PG synthase (PGS) activity and PG receptor signalling were determined in subcutaneous (SC), gonadal (GN) WAT and adipocytes. METHODS AND RESULTS In obese humans, low-dose ASA (150 mg day(-1) for 10 days) inhibited systemic IL-6 and reduced IL-6 release from SC WAT ex vivo (0.2 mM). Similarly, in mice, ASA (0.2 and 2.0 mg kg(-1)) suppressed SC WAT 6-keto-PGF(1alpha) (a stable metabolite of prostacyclin) and IL-6 release. Although both COX isoforms are comparably expressed, prostacyclin synthase expression is higher in GN WAT, with levels of activity correlating directly with IL-6. Both ASA (5 mM) and NS-398 (COX-2 selective inhibitor <or=1 microM), but not SC-560 (COX-1 selective inhibitor <or=1 microM), attenuated IL-6 release from murine WAT in vitro and abolished its depot differences. Prostacyclin receptor (IP) and, to a lesser extent, PGE(2) (EP2 and EP4) receptor agonists elevated the release of IL-6 from adipocytes. CONCLUSIONS In adipose tissue, constitutive COX-2-coupled prostacyclin triggers the release of basal IL-6, which in obese subjects is significantly dampened by ASA ingestion, thus offering a novel, modifiable pathway to regulate the potentially pathological component of this cytokine.
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18
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Zechner R, Kienesberger PC, Haemmerle G, Zimmermann R, Lass A. Adipose triglyceride lipase and the lipolytic catabolism of cellular fat stores. J Lipid Res 2008; 50:3-21. [PMID: 18952573 DOI: 10.1194/jlr.r800031-jlr200] [Citation(s) in RCA: 394] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Fatty acids (FAs) are essential components of all lipid classes and pivotal substrates for energy production in all vertebrates. Additionally, they act directly or indirectly as signaling molecules and, when bonded to amino acid side chains of peptides, anchor proteins in biological membranes. In vertebrates, FAs are predominantly stored in the form of triacylglycerol (TG) within lipid droplets of white adipose tissue. Lipid droplet-associated TGs are also found in most nonadipose tissues, including liver, cardiac muscle, and skeletal muscle. The mobilization of FAs from all fat depots depends on the activity of TG hydrolases. Currently, three enzymes are known to hydrolyze TG, the well-studied hormone-sensitive lipase (HSL) and monoglyceride lipase (MGL), discovered more than 40 years ago, as well as the relatively recently identified adipose triglyceride lipase (ATGL). The phenotype of HSL- and ATGL-deficient mice, as well as the disease pattern of patients with defective ATGL activity (due to mutation in ATGL or in the enzyme's activator, CGI-58), suggest that the consecutive action of ATGL, HSL, and MGL is responsible for the complete hydrolysis of a TG molecule. The complex regulation of these enzymes by numerous, partially uncharacterized effectors creates the "lipolysome," a complex metabolic network that contributes to the control of lipid and energy homeostasis. This review focuses on the structure, function, and regulation of lipolytic enzymes with a special emphasis on ATGL.
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Affiliation(s)
- Rudolf Zechner
- Institute of Molecular Biosciences, University of Graz, Austria.
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19
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Nino-Fong R, Collins T, Chan C. Nutrigenomics, beta-cell function and type 2 diabetes. Curr Genomics 2008; 8:1-29. [PMID: 18645625 PMCID: PMC2474685 DOI: 10.2174/138920207780076947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 08/12/2006] [Accepted: 10/13/2006] [Indexed: 01/15/2023] Open
Abstract
INTRODUCTION The present investigation was designed to investigate the accuracy and precision of lactate measurement obtained with contemporary biosensors (Chiron Diagnostics, Nova Biomedical) and standard enzymatic photometric procedures (Sigma Diagnostics, Abbott Laboratories, Analyticon). MATERIALS AND METHODS Measurements were performed in vitro before and after the stepwise addition of 1 molar sodium lactate solution to samples of fresh frozen plasma to systematically achieve lactate concentrations of up to 20 mmol/l. RESULTS Precision of the methods investigated varied between 1% and 7%, accuracy ranged between 2% and -33% with the variability being lowest in the Sigma photometric procedure (6%) and more than 13% in both biosensor methods. CONCLUSION Biosensors for lactate measurement provide adequate accuracy in mean with the limitation of highly variable results. A true lactate value of 6 mmol/l was found to be presented between 4.4 and 7.6 mmol/l or even with higher difference. Biosensors and standard enzymatic photometric procedures are only limited comparable because the differences between paired determinations presented to be several mmol. The advantage of biosensors is the complete lack of preanalytical sample preparation which appeared to be the major limitation of standard photometry methods.
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Affiliation(s)
- R Nino-Fong
- Department of Biomedical Sciences, University of Prince Edward Island, Charlottetown, PE C1A 4P3 Canada
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20
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Catecholamine-induced lipolysis in adipose tissue and skeletal muscle in obesity. Physiol Behav 2008; 94:219-30. [DOI: 10.1016/j.physbeh.2008.01.002] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 01/07/2008] [Accepted: 01/07/2008] [Indexed: 12/20/2022]
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Fernández-Quintela A, Churruca I, Portillo MP. The role of dietary fat in adipose tissue metabolism. Public Health Nutr 2008; 10:1126-31. [PMID: 17903320 DOI: 10.1017/s1368980007000602] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Energy intake and expenditure tend on average to remain adjusted to each other in order to maintain a stable body weight, which is only likely to be sustained if the fuel mix oxidised is equivalent to the nutrient content of the diet. Whereas protein and carbohydrate degradation and oxidation are closely adjusted to their intakes, fat balance regulation is less precise and that fat is more likely to be stored than oxidised. It has been demonstrated that dietary fatty acids have an influence not only on the fatty acid composition of membrane phospholipids, thus modulating several metabolic processes that take place in the adipocyte, but also on the composition and the quantity of different fatty acids in adipose tissue. Moreover, dietary fatty acids also modulate eicosanoid presence, which have hormone-like activities in lipid metabolism regulation in adipose tissue. Until recently, the adipocyte has been considered to be no more than a passive tissue for storage of excess energy. However, there is now compelling evidence that adipocytes have a role as endocrine secretory cells. Some of the adipokines produced by adipose tissue, such as leptin and adiponectin, act on adipose tissue in an autocrine/paracrine manner to regulate adipocyte metabolism. Furthermore, dietary fatty acids may influence the expression of adipokines. The nutrients are among the most influential of the environmental factors that determine the way adipose tissue genes are expressed by functioning as regulators of gene transcription. Therefore, not only dietary fat amount but also dietary fat composition influence adipose tissue metabolism.
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Affiliation(s)
- Alfredo Fernández-Quintela
- Department of Nutrition and Food Science, University of País Vasco, Paseo de la Universidad 7, 01006 Vitoria, Spain
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22
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Hétu PO, Riendeau D. Down-regulation of microsomal prostaglandin E2 synthase-1 in adipose tissue by high-fat feeding. Obesity (Silver Spring) 2007; 15:60-8. [PMID: 17228032 DOI: 10.1038/oby.2007.514] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Prostaglandin (PG)E2 is a lipid mediator implicated in inflammatory diseases and in the regulation of lipolysis and adipocyte differentiation. This work was, thus, undertaken to study the regulation of the various PGE2 synthases (PGESs) in obesity. RESEARCH METHODS AND PROCEDURES C57Bl/6 mice were subjected to a high-fat or regular diet for 12 weeks. The levels of PGE2 in white adipose tissue (WAT) of lean and obese mice were quantified by liquid chromatography-mass spectrometry, and the change in expression of the three major PGES caused by diet-induced obesity was characterized by Western blotting. Human preadipocytes and 3T3-L1 cells were used to assess the expression of microsomal prostaglandin E2 synthase-1 (mPGES-1) during adipogenesis. RESULTS mPGES-1, mPGES-2, and cytosolic PGES proteins were all detected in WAT of lean animals. mPGES-1 was expressed at higher levels in WAT than in any other tissues examined and was more abundant (3- to 4-fold) in epididymal (visceral) compared with inguinal (subcutaneous) WAT. Expression of mPGES-1 was also detected in undifferentiated and differentiated 3T3-L1 cells and in human primary subcutaneous preadipocytes at all stages of adipogenesis. The mPGES-1 protein was substantially down-regulated in epididymal and inguinal WAT of obese mice, whereas mPGES-2 and cytosolic PGES remained relatively stable. Concordantly, the PGE2 levels in obese inguinal WAT were significantly lower than those of lean animals. DISCUSSION These data suggest that mPGES-1 is the major form of PGESs contributing to the synthesis of PGE2 in WAT and that its down-regulation might be involved in the alterations of lipolysis and adipogenesis associated with obesity.
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Affiliation(s)
- Pierre-Olivier Hétu
- Department of Biochemistry and Molecular Biology, Merck Frosst Centre for Therapeutic Research, 16711 Trans-Canada Hwy, Kirkland, Quebec, Canada H9H 3L1
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23
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Benyó Z, Gille A, Kero J, Csiky M, Suchánková MC, Nüsing RM, Moers A, Pfeffer K, Offermanns S. GPR109A (PUMA-G/HM74A) mediates nicotinic acid-induced flushing. J Clin Invest 2006; 115:3634-40. [PMID: 16322797 PMCID: PMC1297235 DOI: 10.1172/jci23626] [Citation(s) in RCA: 263] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2004] [Accepted: 09/13/2005] [Indexed: 01/08/2023] Open
Abstract
Nicotinic acid (niacin) has long been used as an antidyslipidemic drug. Its special profile of actions, especially the rise in HDL-cholesterol levels induced by nicotinic acid, is unique among the currently available pharmacological tools to treat lipid disorders. Recently, a G-protein-coupled receptor, termed GPR109A (HM74A in humans, PUMA-G in mice), was described and shown to mediate the nicotinic acid-induced antilipolytic effects in adipocytes. One of the major problems of the pharmacotherapeutical use of nicotinic acid is a strong flushing response. This side effect, although harmless, strongly affects patient compliance. In the present study, we show that mice lacking PUMA-G did not show nicotinic acid-induced flushing. In addition, flushing in response to nicotinic acid was also abrogated in the absence of cyclooxygenase type 1, and mice lacking prostaglandin D(2) (PGD(2)) and prostaglandin E(2) (PGE(2)) receptors had reduced flushing responses. The mouse orthologue of GPR109A, PUMA-G, is highly expressed in macrophages and other immune cells, and transplantation of wild-type bone marrow into irradiated PUMA-G-deficient mice restored the nicotinic acid-induced flushing response. Our data clearly indicate that GPR109A mediates nicotinic acid-induced flushing and that this effect involves release of PGE(2) and PGD(2), most likely from immune cells of the skin.
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MESH Headings
- Adipocytes/metabolism
- Animals
- Bone Marrow Transplantation
- Calcium/metabolism
- Cyclooxygenase 1/genetics
- Cyclooxygenase 1/metabolism
- DNA Primers/chemistry
- Fatty Acids/metabolism
- Hypolipidemic Agents/therapeutic use
- Immune System
- Ligands
- Lipids
- Lipoproteins, HDL/metabolism
- Lipoproteins, LDL/metabolism
- Macrophages/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Models, Biological
- Niacin/metabolism
- Niacin/therapeutic use
- Nicotinic Acids/metabolism
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, G-Protein-Coupled/physiology
- Receptors, Immunologic/genetics
- Receptors, Nicotinic/genetics
- Receptors, Nicotinic/metabolism
- Receptors, Nicotinic/physiology
- Receptors, Prostaglandin/genetics
- Receptors, Prostaglandin E/genetics
- Receptors, Prostaglandin E, EP1 Subtype
- Reverse Transcriptase Polymerase Chain Reaction
- Skin/immunology
- Time Factors
- Triglycerides/metabolism
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Affiliation(s)
- Zoltán Benyó
- Institute of Pharmacology, University of Heidelberg, Heidelberg, Germany
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24
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Abstract
Release of fatty acids (FAs) from adipose tissue through lipolysis in fat cells is a key event in many processes. FAs are not only energy substrates but also signalling molecules and substrates for lipoprotein production by the liver. Fat cells consist of>95% triglycerides that are hydrolysed during lipolysis to glycerol and FAs. The major rate-limiting factor for lipolysis is hormone-sensitive lipase, but additional lipases such as adipose tissue triglyceride lipase may also play a role. The regulation of human fat cell lipolysis is, in many ways, species unique. Only catecholamines, insulin and natriuretic peptides have pronounced acute effects. Catecholamines influence lipolysis through four different adrenoceptor subtypes, in contrast to rodents where only one subtype (beta(3)) is of major importance. There are regional variations in adipocyte lipolysis leading to more release of FAs from the visceral than subcutaneous adipose tissue during hormone stimulation (insulin, catecholamines). Since, only visceral fat is linked to the liver (by the portal vein), alterations in visceral adipocyte tissue lipolysis have direct effects on the liver through portal FA release. The regional variations in lipolysis are further enhanced in obesity and polycystic ovarian syndrome, and are of importance for dyslipidaemia, hyperinsulinaemia and glucose intolerance in these conditions. There is a marked elevation of circulating FA levels among the obese, which may be due to enhanced production of tumour necrosis factor alpha in adipose tissue. This cytokine stimulates lipolysis through so-called MAP kinases. Pharmacological agents in clinical practice such as nicotinic acid and glitazones exert lipid-lowering and glucose-lowering effects, respectively, by decreasing FA output from the adipose tissue. This review covers the biochemistry, regulation and clinical aspects of human fat cell lipolysis.
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Affiliation(s)
- Peter Arner
- Department of Medicine M63, Karolinska Institutet, Karolinska University Hospital, Huddinge, SE-141 86 Stockholm, Sweden.
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25
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Wang W, Andersson M, Lõnnroth C, Svanberg E, Lundholm K. Prostaglandin E and prostacyclin receptor expression in tumor and host tissues from MCG 101-bearing mice: a model with prostanoid-related cachexia. Int J Cancer 2005; 115:582-90. [PMID: 15704139 DOI: 10.1002/ijc.20539] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Preclinical and clinical studies in our laboratory have suggested that prostaglandin (PG) E2 is involved in anorexia and cachexia development, although the role of COX pathways on the pathogenesis of cancer cachexia remains to be clarified. Expressions of PGE (EP1, EP2, EP3alpha,beta,gamma and EP4) and PGI (IP) receptors in the central nervous system (brain cortex, hypothalamus and brain stem), in peripheral (liver, white adipose tissue and skeletal muscle) and tumor tissue from MCG-101-bearing mice with and without indomethacin treatment were investigated by RT-PCR and immunohistochemistry. Expression of EP1 in the liver and EP4 receptor in white adipose tissue were upregulated and responded to indomethacin treatment, while downregulated expression of EP3 in skeletal muscle from tumor-bearing mice was unresponsive to indomethacin treatment despite improved carcass weight. Expression of EP and IP receptors in brain and tumor tissue from tumor-bearing mice were neither related nor responsive to systemic PGE2 levels including increased IL-1beta, IL-6 and TNF-alpha host activities. The expression IP receptor in CNS, peripheral tissue and tumor tissue was unchanged by cachexia development. Our results suggest that transcription of EP receptors in liver, fat and skeletal muscle tissue may be a control level for host metabolic alterations during tumor progression, while overall EP and IP receptor expression in CNS did not indicate an important control level for appetite regulation in MCG 101-bearing mice despite prostanoid related anorexia.
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MESH Headings
- Animals
- Base Sequence
- Body Weight
- Cachexia/physiopathology
- DNA Primers
- DNA, Complementary/genetics
- Dinoprostone/metabolism
- Disease Models, Animal
- Energy Intake
- Female
- Indomethacin/pharmacology
- Methylcholanthrene
- Mice
- Mice, Inbred C57BL
- Organ Specificity
- Prostaglandins/physiology
- RNA, Messenger/genetics
- RNA, Messenger/isolation & purification
- RNA, Neoplasm/genetics
- RNA, Neoplasm/isolation & purification
- Receptors, Prostaglandin E/drug effects
- Receptors, Prostaglandin E/genetics
- Sarcoma, Experimental/chemically induced
- Sarcoma, Experimental/genetics
- Sarcoma, Experimental/physiopathology
- Transcription, Genetic
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Affiliation(s)
- Wenhua Wang
- Surgical Metabolic Research Laboratory at Lundberg Laboratory for Cancer Research, Department of Surgery, Sahlgrenska University Hospital, Göteborg, Sweden
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26
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Large V, Peroni O, Letexier D, Ray H, Beylot M. Metabolism of lipids in human white adipocyte. DIABETES & METABOLISM 2004; 30:294-309. [PMID: 15525872 DOI: 10.1016/s1262-3636(07)70121-0] [Citation(s) in RCA: 187] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Adipose tissue is considered as the body's largest storage organ for energy in the form of triacylglycerols, which are mobilized through lipolysis process, to provide fuel to other organs and to deliver substrates to liver for gluconeogenesis (glycerol) and lipoprotein synthesis (free fatty acids). The release of glycerol and free fatty acids from human adipose tissue is mainly dependent on hormone-sensitive lipase which is intensively regulated by hormones and agents, such as insulin (inhibition of lipolysis) and catecholamines (stimulation of lipolysis). A special attention is paid to the recently discovered perilipins which could regulate the activity of the lipase hormono-sensible. Most of the plasma triacylglycerols are provided by dietary lipids, secreted from the intestine in the form of chylomicron or from the liver in the form of VLDL. Released into circulation as non-esterified fatty acids by lipoprotein lipase, those are taken up by adipose tissue via specific plasma fatty acid transporters (CD36, FATP, FABPpm) and used for triacylglycerol synthesis. A small part of triacylglycerols is synthesized into adipocytes from carbohydrates (lipogenesis) but its regulation is still debated in human. Physiological factors such as dieting/fasting regulate all these metabolic pathways, which are also modified in pathological conditions e.g. obesity.
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Affiliation(s)
- V Large
- INSERM 499, Faculté de médecine Laennec, rue Paradin, 69372 Lyon.
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27
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Fortuño A, Rodríguez A, Gómez-Ambrosi J, Frühbeck G, Díez J. Adipose tissue as an endocrine organ: role of leptin and adiponectin in the pathogenesis of cardiovascular diseases. J Physiol Biochem 2003; 59:51-60. [PMID: 12903905 DOI: 10.1007/bf03179868] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Obesity, the most common nutritional disorder in industrial countries, is associated with increased cardiovascular mortality and morbidity. Nevertheless, the molecular basis linking obesity with cardiovascular disturbances have not yet been fully clarified. Recent advances in the biology of adipose tissue indicate that it is not simply an energy storage organ, but also a secretory organ, producing a variety of bioactive substances, including leptin and adiponectin, that may influence the function as well as the structural integrity of the cardiovascular system. Leptin, besides being a satiety signal for the central nervous system and to be related to insulin and glucose metabolism, may also play an important role in regulating vascular tone because of the widespread distribution of functional receptors in the vascular cells. On the other hand, the more recently discovered protein, adiponectin, seems to play a protective role in experimental models of vascular injury, in probable relation to its ability to suppress the attachment of monocytes to endothelial cells, which is an early event in the atherosclerotic process. There is already considerable evidence linking altered production of some adipocyte hormones with the cardiovascular complications of obesity. Therefore, the knowledge of alterations in the endocrine function of adipose tissue may help to further understand the high cardiovascular risk associated with obesity.
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Affiliation(s)
- A Fortuño
- Division of Cardiovascular Pathophysiology, Centre for Applied Medical Research, 31008 Pamplona, Spain.
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28
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Fain JN, Kanu A, Bahouth SW, Cowan GSM, Hiler ML, Leffler CW. Comparison of PGE2, prostacyclin and leptin release by human adipocytes versus explants of adipose tissue in primary culture. Prostaglandins Leukot Essent Fatty Acids 2002; 67:467-73. [PMID: 12468269 DOI: 10.1054/plef.2002.0430] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The present studies were designed to investigate the sites of PGE(2), prostacyclin and leptin formation in human adipose tissue. Most of the PGE(2) and prostacyclin formation by adipose tissue explants from obese humans after 48 h in primary culture was due to blood vessels and other tissues not digested by collagenase. However, there was appreciable PGE(2) formation by adipocytes over a 48 h incubation and leptin formation was only seen in adipocytes. An increase in COX-2 immunoreactive protein was also seen after incubation of isolated human adipocytes for 48 h. The release of PGE(2) by adipocytes incubated for 48 h was about 4% that by intact adipose tissue explants while the release of prostacyclin was about 1.5% that by tissue. However, in a different experimental design where PGE(2) formation was measured over 2 h in the presence of 20 microM arachidonic acid the formation of PGE(2) by adipocytes after 48 h prior incubation in primary culture was 38% of that by tissue explants. Dexamethasone enhanced leptin release by adipocytes while inhibiting PGE(2) release and COX-2 up-regulation. The mechanisms involved in up-regulation of COX-2 activity during primary culture of adipocytes and the inhibition of this by dexamethasone do not appear to involve p38 MAPK or p42-44 MAPK. Interleukin I(beta) further enhanced PGE(2) formation by adipocytes but did not affect leptin formation. In conclusion, these data indicate that leptin release is exclusively a function of adipocytes while prostanoids are made by both adipocytes and the other cells present in human adipose tissue
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Affiliation(s)
- J N Fain
- Department of Molecular Sciences, University of Tennessee Health Science Center, Memphis, TN, USA.
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29
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Yokota T, Meka CR, Medina KL, Igarashi H, Comp PC, Takahashi M, Nishida M, Oritani K, Miyagawa JI, Funahashi T, Tomiyama Y, Matsuzawa Y, Kincade PW. Paracrine regulation of fat cell formation in bone marrow cultures via adiponectin and prostaglandins. J Clin Invest 2002. [DOI: 10.1172/jci0214506] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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30
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Yokota T, Meka CSR, Medina KL, Igarashi H, Comp PC, Takahashi M, Nishida M, Oritani K, Miyagawa JI, Funahashi T, Tomiyama Y, Matsuzawa Y, Kincade PW. Paracrine regulation of fat cell formation in bone marrow cultures via adiponectin and prostaglandins. J Clin Invest 2002; 109:1303-10. [PMID: 12021245 PMCID: PMC2447671 DOI: 10.1172/jci14506] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Adiponectin, an adipocyte-derived hormone, was recently shown to have potential therapeutic applications in diabetes and obesity because of its influence on glucose and lipid metabolism. We found that brown fat in normal human bone marrow contains this protein and used marrow-derived preadipocyte lines and long-term cultures to explore potential roles in hematopoiesis. Recombinant adiponectin blocked fat cell formation in long-term bone marrow cultures and inhibited the differentiation of cloned stromal preadipocytes. Adiponectin also caused elevated expression of cyclooxygenase-2 (COX-2) by these stromal cells and induced release of prostaglandin E(2) (PGE(2)). The COX-2 inhibitor Dup-697 prevented the inhibitory action of adiponectin on preadipocyte differentiation, suggesting involvement of stromal cell-derived prostanoids. Furthermore, adiponectin failed to block fat cell generation when bone marrow cells were derived from B6,129S(Ptgs2tm1Jed) (COX-2(+/-)) mice. These observations show that preadipocytes represent direct targets for adiponectin action, establishing a paracrine negative feedback loop for fat regulation. They also link adiponectin to the COX-2-dependent PGs that are critical in this process.
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Affiliation(s)
- Takafumi Yokota
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
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31
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Fain JN, Ballou LR, Bahouth SW. Obesity is induced in mice heterozygous for cyclooxygenase-2. Prostaglandins Other Lipid Mediat 2001; 65:199-209. [PMID: 11444591 DOI: 10.1016/s0090-6980(01)00136-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In mice heterozygous for the cyclooxygenase-2 gene (COX-2+/-) the body weight was enhanced by 33% as compared to homozygous COX-2-/- mice. The weights of the gonadal fat pads in COX-2+/- mice were enhanced by 3.5 to 4.7 fold as compared to COX-2-/- mice and by 1.5 to 3.5 fold as compared to wild-type controls+/+ Serum leptin levels and leptin release by cultured adipose tissue of COX-2+/- mice were both elevated as compared to either control or COX-2-/- animals. The basal release of PGE2 or 6 keto PGF1alpha per fat pad over a 24 h incubation of adipose tissue was reduced by 80% and 95% respectively in tissue from COX-2-/- mice. NS-398, a specific COX-2 inhibitor, inhibited leptin release by 27% in adipose tissue from control mice, 31% in tissue from COX-1-/- mice and by 23% in tissue from COX-2+/- mice while having no effect on leptin release by adipose tissue from COX-2-/- mice. These data indicate that heterozygous COX-2 mice develop obesity which is not secondary to a defect in leptin release by adipose tissue.
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Affiliation(s)
- J N Fain
- Department of Molecular Sciences, College of Medicine, The University of Tennessee Health Science Center, Memphis 38163, USA.
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32
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Bruun JM, Pedersen SB, Richelsen B. Regulation of interleukin 8 production and gene expression in human adipose tissue in vitro. J Clin Endocrinol Metab 2001; 86:1267-73. [PMID: 11238519 DOI: 10.1210/jcem.86.3.7264] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A variety of cytokines and other compounds are produced in the human adipose tissue and may have autocrine functions in the adipose tissue as well as be involved in the complications seen in association with obesity. Because it recently has been reported that interleukin 8 (IL-8), through its effects on the macrophage and endothelial cell, may be involved in the pathogenesis of atherosclerosis, we found it of interest to investigate whether IL-8 is produced in human adipose tissue in vitro. Human sc adipose tissue was investigated both in incubations with whole adipose tissue fragments as well as with isolated mature adipocytes. In adipose tissue fragments, IL-1beta (3 nM) and tumor necrosis factor alpha (0.6 nM) were able to stimulate IL-8 production by 12-fold and 5-fold, respectively (P < 0.001), when incubated for 48 h. Incubations with isolated adipocytes were performed up to 6 h, and IL-1beta and tumor necrosis factor alpha significantly increased IL-8 production by 50-60% (P < 0.05). Dexamethasone (50 nM) decreased IL-8 production from adipose tissue fragments by 57% (P < 0.01) and from adipocytes by 37% (P < 0.05). IL-8 messenger RNA expression in adipocytes incubated with IL-1beta was increased already after 2 h (P < 0.05). Thus, the effect of proinflammatory cytokines and dexamethasone on IL-8 production in adipose tissue seems to be mediated at the transcriptional level. In conclusion, it is demonstrated for the first time that IL-8 is produced and released from human adipose tissue and from isolated adipocytes in vitro, which may indicate that IL-8 from adipose tissue could be involved in some of the obesity-related complications.
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Affiliation(s)
- J M Bruun
- Department of Endocrinology and Metabolism C, Aarhus Amtssygehus, Aarhus University Hospital and Faculty of Health Sciences, Aarhus University, DK-8000 Aarhus C, Denmark.
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33
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Kim S, Moustaid-Moussa N. Secretory, endocrine and autocrine/paracrine function of the adipocyte. J Nutr 2000; 130:3110S-3115S. [PMID: 11110881 DOI: 10.1093/jn/130.12.3110s] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Obesity is a major public health problem in Western countries, and >55% of adult Americans are overweight or obese. A major contributor to the epidemic of obesity is the current environment, which is characterized by increased availability of high energy foods and decreased physical activity. Several studies also demonstrated that genetic susceptibility contributes to obesity in some populations. Obesity research has focused primarily on the role of the hypothalamus in neuroendocrine regulation of food intake. However, a growing number of studies support a potential contribution of adipose tissue, via its newly discovered secretory function, to the pathogenesis of obesity and co-morbid conditions including cardiovascular disease, diabetes and hypertension. This paper will review the role of four factors secreted by adipose tissue (leptin, agouti, angiotensin II and prostaglandins) and their functions in the regulation of energy balance and whole-body homeostasis. Several other peptide and nonpeptide substances are secreted from adipose tissue; their function and regulation have been documented extensively.
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Affiliation(s)
- S Kim
- Department of Nutrition, University of Tennessee, Knoxville, TN 37996-1900, USA
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34
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Fain JN, Leffler CW, Bahouth SW, Rice AM, Rivkees SA. Regulation of leptin release and lipolysis by PGE2 in rat adipose tissue. Prostaglandins Other Lipid Mediat 2000; 62:343-50. [PMID: 11060898 DOI: 10.1016/s0090-6980(00)00088-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The role of eicosanoids formed by adipose tissue from rats was examined in the presence of the specific cyclooxygenase-2 inhibitor NS-398. This agent totally blocked the release of prostaglandin E2 (PGE2) by rat adipose tissue over a 24-h incubation in primary culture. The final concentration of PGE2 after 24 h was 12 nM, and half-maximal inhibition of PGE2 formation required 35 nM NS-398. While inhibition of PGE2 formation by NS-398 had no effect on basal leptin release or lipolysis, it enhanced the lipolytic action of 10 nM isoproterenol by 36%. The in vivo administration of PGE2 doubled serum leptin. PGE2 also directly stimulated leptin release by rat adipose tissue incubated in the presence of 25 nM dexamethasone, which inhibited endogenous PGE2 formation by 94%. The inhibition of lipolysis as well as the stimulation of leptin release by PGE2 were mimicked by N6-cyclopentyladenosine (CPA). These data indicate that exogenous PGE2 can stimulate leptin release by adipose tissue when the basal formation of PGE2 is blocked by dexamethasone. However, while the endogenous formation of PGE2 does not appear to regulate basal lipolysis or leptin release, it may play a role in the activation of lipolysis by catecholamines.
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Affiliation(s)
- J N Fain
- Department of Biochemistry, College of Medicine, University of Tennessee, Memphis 38163, USA.
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35
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Fain JN, Leffler CW, Bahouth SW. Eicosanoids as endogenous regulators of leptin release and lipolysis by mouse adipose tissue in primary culture. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)32003-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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36
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Fain JN, Bahouth SW. Regulation of leptin release by mammalian adipose tissue. Biochem Biophys Res Commun 2000; 274:571-5. [PMID: 10924319 DOI: 10.1006/bbrc.2000.3168] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- J N Fain
- Department of Biochemistry, University of Tennessee, Memphis, Memphis, Tennessee, 38163, USA
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37
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Børglum JD, Pedersen SB, Ailhaud G, Négrel R, Richelsen B. Differential expression of prostaglandin receptor mRNAs during adipose cell differentiation. Prostaglandins Other Lipid Mediat 1999; 57:305-17. [PMID: 10480485 DOI: 10.1016/s0090-6980(98)00082-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To clarify the molecular basis for the prostaglandin (PG) mediated effects in adipose cells at various stages of their development, expression of mRNAs encoding receptors specific for prostaglandin E2, F2alpha and I2 (i.e. EP, FP, and IP receptors) was investigated in differentiating clonal Ob1771 pre-adipocytes, as well as in mouse primary adipose precursor cells and mature adipocytes. We have further characterized the differential expression of mRNAs encoding three subtypes of the EP receptor, i.e. EP1, EP3, and EP4, and examined the expression of mRNAs encoding the three isoforms (alpha, beta, and gamma) of the EP3 receptor. Altogether the results show that the expression of IP, FP, EP1, and EP4 receptor mRNAs was considerably more pronounced in pre-adipose cells than in adipose cells, mRNAs encoding the alpha, beta, and gamma isoforms of the EP3 receptor were all exclusively expressed in freshly isolated mature adipocytes. These data may indicate that PGI2, PGF2alpha, and PGE2 may interact directly with specific receptors in pre-adipose cells, whose transduction mechanisms are known to affect maturation related changes. In mature adipocytes, however, the equipment of mRNAs encoding the EP3 receptor isoforms is in agreement with the well known effect of PGE2 on adenylate cyclase and lipolysis in mature adipocytes.
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Affiliation(s)
- J D Børglum
- Department of Endocrinology & Metabolism, Aarhus University Hospital, Denmark
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38
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Abstract
The adipocyte plays a critical role in energy balance. Adipose tissue growth involves an increase in adipocyte size and the formation of new adipocytes from precursor cells. For the last 20 years, the cellular and molecular mechanisms of adipocyte differentiation have been extensively studied using preadipocyte culture systems. Committed preadipocytes undergo growth arrest and subsequent terminal differentiation into adipocytes. This is accompanied by a dramatic increase in expression of adipocyte genes including adipocyte fatty acid binding protein and lipid-metabolizing enzymes. Characterization of regulatory regions of adipose-specific genes has led to the identification of the transcription factors peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and CCAAT/enhancer binding protein (C/EBP), which play a key role in the complex transcriptional cascade during adipocyte differentiation. Growth and differentiation of preadipocytes is controlled by communication between individual cells or between cells and the extracellular environment. Various hormones and growth factors that affect adipocyte differentiation in a positive or negative manner have been identified. In addition, components involved in cell-cell or cell-matrix interactions such as preadipocyte factor-1 and extracellular matrix proteins are also pivotal in regulating the differentiation process. Identification of these molecules has yielded clues to the biochemical pathways that ultimately result in transcriptional activation via PPAR-gamma and C/EBP. Studies on the regulation of the these transcription factors and the mode of action of various agents that influence adipocyte differentiation will reveal the physiological and pathophysiological mechanisms underlying adipose tissue development.
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Affiliation(s)
- F M Gregoire
- Department of Nutritional Sciences, University of California, Berkeley, USA
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39
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Abstract
Adipose tissue has long been known to house the largest energy reserves in the animal body. Recent research indicates that in addition to this role, the adipocyte functions as a global regulator of energy metabolism. Adipose tissue is exquisitely sensitive to a variety of endocrine and paracrine signals, e.g. insulin, glucagon, glucocorticoids, and tumor necrosis factor (TNF), that combine to control both the secretion of other regulatory factors and the recruitment and differentiation of new adipocytes. The process of adipocyte differentiation is controlled by a cascade of transcription factors, most notably those of the C/EBP and PPAR families, which combine to regulate each other and to control the expression of adipocyte-specific genes. One such gene, i.e. the obese gene, was recently identified and found to encode a hormone, referred to as leptin, that plays a major role in the regulation of energy intake and expenditure. The hormonal and transcriptional control of adipocyte differentiation is discussed, as is the role of leptin and other factors secreted by the adipocyte that participate in the regulation of adipose homeostasis.
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Affiliation(s)
- C S Hwang
- Department of Biological Chemistry, Johns Hopkins University Medical School, Baltimore, Maryland 21205, USA
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40
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Okuno M, Kajiwara K, Imai S, Kobayashi T, Honma N, Maki T, Suruga K, Goda T, Takase S, Muto Y, Moriwaki H. Perilla oil prevents the excessive growth of visceral adipose tissue in rats by down-regulating adipocyte differentiation. J Nutr 1997; 127:1752-7. [PMID: 9278555 DOI: 10.1093/jn/127.9.1752] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We examined the effect of dietary oils with different fatty acid compositions on the growth of visceral adipose tissue in rats. Rats were fed for 4 mo starting at weaning a basal diet containing (12 g/100 g diet) perilla oil rich in (n-3) polyunsaturated fatty acids (PUFA), safflower oil rich in (n-6) PUFA, olive oil rich in monounsaturated fatty acid, or beef tallow rich in saturated fatty acids. The amount of food consumed and body weight gain did not differ among the four dietary groups. The weight of the epididymal fat pad and the serum triglyceride concentration in perilla oil-fed rats were significantly lower (P < 0.05) than those of olive oil- and beef tallow-fed groups. The product of [(volume of individual adipocytes) x (number of adipocytes in epididymal fat pad)], which presumably represents total adipocyte volume in the fat pad, was significantly lower (P < 0.05) in perilla oil-fed rats than in beef tallow- and olive oil-fed groups. Expression of the late genes of adipocyte differentiation, peroxisome proliferator-activated receptor alpha, adipocyte P2 and adipsin, was significantly (P < 0. 05) down-regulated in epididymal fat tissue of rats that had been fed perilla oil rather than beef tallow or olive oil, whereas expression of the early gene, lipoprotein lipase, was not significantly affected. Greater levels (P < 0.05) of (n-3) PUFA in the membrane phospholipid fraction of the fat tissue were observed in perilla oil-fed rats than in the other dietary groups. These results suggest that perilla oil or (n-3) PUFA prevents excessive growth of adipose tissue in rats at least in part by suppressing the late phase of adipocyte differentiation.
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Affiliation(s)
- M Okuno
- First Department of Internal Medicine, Gifu University School of Medicine, Gifu 500, Japan
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41
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Børglum JD, Richelsen B, Darimont C, Pedersen SB, Négrel R. Expression of the two isoforms of prostaglandin endoperoxide synthase (PGHS-1 and PGHS-2) during adipose cell differentiation. Mol Cell Endocrinol 1997; 131:67-77. [PMID: 9256365 DOI: 10.1016/s0303-7207(97)00094-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Expression of mRNAs encoding the two prostaglandin endoperoxide synthase (PGHS) isoenzymes (PGHS-1 and -2) was investigated in differentiating clonal Ob1771 mouse preadipocytes and in mouse adipose tissues. Northern analysis revealed that the expression level of PGHS-1 mRNA was reduced by 98+/-0.2% (P <0.01) during differentiation of Ob1771 cells, whereas PGHS-2 mRNA was not detected. By reverse transcriptase-polymerase chain reaction analysis, however, both PGHS-1 and -2 mRNA was detected in Ob1771 preadipose cells. In addition. mRNAs encoding both isoforms were markedly expressed in primary adipose precursor cells with considerably lower expression levels in mature adipocytes (56 75% reduction, P<0.01). Furthermore, exposure to dexamethasone (10 nM) for both 24 h (explants of adipose tissue) and 48 h (Ob1771 adipose cells) resulted in enhanced expression of PGHS-1 mRNA. whereas expression of PGHS-2 mRNA in explants of adipose tissue (24 h incubation) was reduced by 83 +/- 9% (P<0.05). In contrast, exposure to angiotensin II (100 nM) enhanced expression of PGHS-1 mRNA both in mature adipocytes (4 h incubation) and explants of adipose tissue (24 h incubation), and elevated PGHS-2 mRNA expression in mature adipocytes (4 h incubation). In conclusion, this report suggests a differential expression of PGHS mRNAs during adipose cell differentiation, and further suggests that the machinery for prostaglandin synthesis in mature adipocytes may be induced by various hormones.
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Affiliation(s)
- J D Børglum
- Department of Endocrinology and Metabolism, Aarhus University Hospital, Denmark
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42
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Børglum JD, Vassaux G, Richelsen B, Gaillard D, Darimont C, Ailhaud G, Négrel R. Changes in adenosine A1- and A2-receptor expression during adipose cell differentiation. Mol Cell Endocrinol 1996; 117:17-25. [PMID: 8734470 DOI: 10.1016/0303-7207(95)03728-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Two adenosine receptors A1 and A2 are associated with either stimulation (A2) or inhibition (A1) of adenylate cyclase. Using the clonal cell line Ob1771, we have studied the expression of the two receptors during the process of adipose conversion accelerated by exposure to dexamethasone and 3-isobutyl-l-methylxanthine (IBMX) during the first 3 days post-confluence. The effects mediated by the two receptors on preadipocyte differentiation and adipocyte metabolism were also investigated. The two adenosine agonists NECA and PIA were used as preferential agonists of the A2- and A1-receptor, respectively. In preadipose cells (just confluent), both of the mouse clonal line and human primary culture, NECA dose-dependently stimulated cAMP production with a significant higher potency (P < 0.01) than did PIA. In adipose cells (16-day post-confluent) NECA was found to exert a biphasic effect on forskolin-stimulated cAMP production: i.e., NECA was clearly inhibitory in the femto- to picomolar concentration range whereas this effect gradually diminished at higher concentrations. The effect of PIA in 16-day post-confluent adipose cells however, was purely inhibitory on both cAMP production (IC50: 33.52 +/- 0.44 fM) and lipolysis (64% +/- 7%; P < 0.01). These findings were corroborated by Northern blot analysis which revealed A1-receptor mRNA to be exclusively expressed in the mature adipocytes, whereas A2-receptor mRNA gradually declined during the differentiation process except in 16-day post-confluent cells. In addition, NECA significantly enhanced the effect of corticosterone-induced differentiation by 46.8% (P < 0.05) but failed to have any adipogenic potency acting either alone or in concert with carbaprostacyclin (cPGI2). Thus, endogenous adenosine may have a bimodal action on adipose tissue metabolism mediated through stimulatory A2- and inhibitory A1-receptors, respectively, as a function of adipose conversion.
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Affiliation(s)
- J D Børglum
- Department of Endocrinology and Metabolism, Aarhus Amtssygehus, Aarhus University Hospital, Denmark
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Affiliation(s)
- K N Frayn
- Nuffield Department of Clinical Medicine, Radcliffe Infirmary, Oxford
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Abstract
Adipocyte hyperplasia occurs by the proliferation and differentiation of adipocyte precursor cells or preadipocytes. Although the process of commitment to the adipocyte lineage is poorly understood, a great deal of information has accumulated about the processes and regulatory mechanisms involved in preadipocyte differentiation. The differentiation of preadipocytes is known to be characterized by increased transcription of a number of specific genes. AP-1 and C/EBP binding sites within these genes have been identified as important regulatory sequences. In addition, a specific enhancer sequence has been shown to confer adipose tissue specificity. This article will review the changes in gene transcription that occur during preadipocyte differentiation and how these are regulated. The potential role of autocrine/paracrine acting factors in the proliferation and differentiation of the preadipocyte is also discussed.
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Affiliation(s)
- S C Butterwith
- Agricultural and Food Research Council, Roslin Institute (Edinburgh), Department of Cellular and Molecular Biology, Midlothian, U.K
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