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Purinergic receptor: a crucial regulator of adipose tissue functions. Purinergic Signal 2023; 19:273-281. [PMID: 36515790 PMCID: PMC9984650 DOI: 10.1007/s11302-022-09907-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 11/14/2022] [Indexed: 12/15/2022] Open
Abstract
Obesity is a public-health challenge resulting from an imbalance between energy expenditure and calorie intake. This health problem exacerbates a variety of metabolic complications worldwide. Adipose tissue is an essential regulator of energy homeostasis, and the functions within it are regulated by purinergic receptors. A1R, P2X7R, and P2YR mainly mediate energy homeostasis primarily through regulating energy storage and adipokines secretion in white adipose tissue (WAT). P2X5R is a novel-specific cell surface marker in brown/beige adipocytes. A2R is a promising therapeutic target for stimulating energy expenditure in brown adipose tissue (BAT) and also mediating WAT browning. Based on these features, purinergic receptors may be an appropriate target in treating obesity. In this review, the role of purinergic receptors in different types of adipose tissue is summarized. An improved understanding of purinergic receptor functions in adipose tissue may lead to more effective treatment interventions for obesity and its related metabolic disorders.
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Beerkens BL, Koç Ç, Liu R, Florea BI, Le Dévédec SE, Heitman LH, IJzerman AP, van der Es D. A Chemical Biological Approach to Study G Protein-Coupled Receptors: Labeling the Adenosine A 1 Receptor Using an Electrophilic Covalent Probe. ACS Chem Biol 2022; 17:3131-3139. [PMID: 36279267 PMCID: PMC9679998 DOI: 10.1021/acschembio.2c00589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
G protein-coupled receptors (GPCRs) have been known for decades as attractive drug targets. This has led to the development and approval of many ligands targeting GPCRs. Although ligand binding effects have been studied thoroughly for many GPCRs, there are multiple aspects of GPCR signaling that remain poorly understood. The reasons for this are the difficulties that are encountered upon studying GPCRs, for example, a poor solubility and low expression levels. In this work, we have managed to overcome some of these issues by developing an affinity-based probe for a prototypic GPCR, the adenosine A1 receptor (A1AR). Here, we show the design, synthesis, and biological evaluation of this probe in various biochemical assays, such as SDS-PAGE, confocal microscopy, and chemical proteomics.
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Affiliation(s)
- Bert L.
H. Beerkens
- Division
of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Çağla Koç
- Division
of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Rongfang Liu
- Division
of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Bogdan I. Florea
- Department
of Bioorganic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Sylvia E. Le Dévédec
- Division
of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Laura H. Heitman
- Division
of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands,Oncode
Institute, 2333 CC Leiden, The Netherlands
| | - Adriaan P. IJzerman
- Division
of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Daan van der Es
- Division
of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands,
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Granade ME, Hargett SR, Lank DS, Lemke MC, Luse MA, Isakson BE, Bochkis IM, Linden J, Harris TE. Feeding desensitizes A1 adenosine receptors in adipose through FOXO1-mediated transcriptional regulation. Mol Metab 2022; 63:101543. [PMID: 35811051 PMCID: PMC9304768 DOI: 10.1016/j.molmet.2022.101543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/24/2022] [Accepted: 07/04/2022] [Indexed: 12/03/2022] Open
Abstract
OBJECTIVE Adipose tissue is a critical regulator of energy balance that must rapidly shift its metabolism between fasting and feeding to maintain homeostasis. Adenosine has been characterized as an important regulator of adipocyte metabolism primarily through its actions on A1 adenosine receptors (A1R). We sought to understand the role A1R plays specifically in adipocytes during fasting and feeding to regulate glucose and lipid metabolism. METHODS We used Adora1 floxed mice with an inducible, adiponectin-Cre to generate FAdora1-/- mice, where F designates a fat-specific deletion of A1R. We used these FAdora1-/- mice along with specific agonists and antagonists of A1R to investigate changes in adenosine signaling within adipocytes between the fasted and fed state. RESULTS We found that the adipose tissue response to adenosine is not static, but changes dynamically according to nutrient conditions through the insulin-Akt-FOXO1 axis. We show that under fasted conditions, FAdora1-/- mice had impairments in the suppression of lipolysis by insulin on normal chow and impaired glucose tolerance on high-fat diet. FAdora1-/- mice also exhibited a higher lipolytic response to isoproterenol than WT controls when fasted, however this difference was lost after a 4-hour refeeding period. We demonstrate that FOXO1 binds to the A1R promoter, and refeeding leads to a rapid downregulation of A1R transcript and desensitization of adipocytes to A1R agonism. Obesity also desensitizes adipocyte A1R, and this is accompanied by a disruption of cyclical changes in A1R transcription between fasting and refeeding. CONCLUSIONS We propose that FOXO1 drives high A1R expression under fasted conditions to limit excess lipolysis during stress and augment insulin action upon feeding. Subsequent downregulation of A1R under fed conditions leads to desensitization of these receptors in adipose tissue. This regulation of A1R may facilitate reentrance into the catabolic state upon fasting.
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Affiliation(s)
- Mitchell E Granade
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Stefan R Hargett
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Daniel S Lank
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Michael C Lemke
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Melissa A Luse
- Department of Molecular Physiology and Biophysics, University of Virginia, Charlottesville, VA, USA
| | - Brant E Isakson
- Department of Molecular Physiology and Biophysics, University of Virginia, Charlottesville, VA, USA
| | - Irina M Bochkis
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Joel Linden
- Department of Medicine, Center for Immunity, Inflammation and Regenerative Medicine, University of Virginia, Charlottesville, VA, USA
| | - Thurl E Harris
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.
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Campos-Martins A, Bragança B, Correia-de-Sá P, Fontes-Sousa AP. Pharmacological Tuning of Adenosine Signal Nuances Underlying Heart Failure With Preserved Ejection Fraction. Front Pharmacol 2021; 12:724320. [PMID: 34489711 PMCID: PMC8417789 DOI: 10.3389/fphar.2021.724320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 08/04/2021] [Indexed: 12/30/2022] Open
Abstract
Heart failure with preserved ejection fraction (HFpEF) roughly represents half of the cardiac failure events in developed countries. The proposed 'systemic microvascular paradigm' has been used to explain HFpHF presentation heterogeneity. The lack of effective treatments with few evidence-based therapeutic recommendations makes HFpEF one of the greatest unmet clinical necessities worldwide. The endogenous levels of the purine nucleoside, adenosine, increase significantly following cardiovascular events. Adenosine exerts cardioprotective, neuromodulatory, and immunosuppressive effects by activating plasma membrane-bound P1 receptors that are widely expressed in the cardiovascular system. Its proven benefits have been demonstrated in preclinical animal tests. Here, we provide a comprehensive and up-to-date critical review about the main therapeutic advantages of tuning adenosine signalling pathways in HFpEF, without discounting their side effects and how these can be seized.
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Affiliation(s)
- Alexandrina Campos-Martins
- Laboratório de Farmacologia e Neurobiologia, Centro de Investigação Farmacológica e Inovação Medicamentosa (MedInUP), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto (ICBAS-UP), Porto, Portugal
| | - Bruno Bragança
- Laboratório de Farmacologia e Neurobiologia, Centro de Investigação Farmacológica e Inovação Medicamentosa (MedInUP), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto (ICBAS-UP), Porto, Portugal.,Department of Cardiology, Centro Hospitalar Tâmega e Sousa, Penafiel, Portugal
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia, Centro de Investigação Farmacológica e Inovação Medicamentosa (MedInUP), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto (ICBAS-UP), Porto, Portugal
| | - Ana Patrícia Fontes-Sousa
- Laboratório de Farmacologia e Neurobiologia, Centro de Investigação Farmacológica e Inovação Medicamentosa (MedInUP), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto (ICBAS-UP), Porto, Portugal
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5
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Long residence time adenosine A1 receptor agonists produce sustained wash-resistant antilipolytic effect in rat adipocytes. Biochem Pharmacol 2019; 164:45-52. [DOI: 10.1016/j.bcp.2019.03.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Accepted: 03/20/2019] [Indexed: 02/06/2023]
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Carrageta DF, Dias TR, Alves MG, Oliveira PF, Monteiro MP, Silva BM. Anti-obesity potential of natural methylxanthines. J Funct Foods 2018. [DOI: 10.1016/j.jff.2018.02.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Pardo F, Villalobos-Labra R, Chiarello DI, Salsoso R, Toledo F, Gutierrez J, Leiva A, Sobrevia L. Molecular implications of adenosine in obesity. Mol Aspects Med 2017; 55:90-101. [PMID: 28104382 DOI: 10.1016/j.mam.2017.01.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 12/30/2016] [Accepted: 01/13/2017] [Indexed: 12/31/2022]
Abstract
Adenosine has broad activities in organisms due to the existence of multiple receptors, the differential adenosine concentrations necessary to activate these receptors and the presence of proteins able to synthetize, degrade or transport this nucleoside. All adenosine receptors have been reported to be involved in glucose homeostasis, inflammation, adipogenesis, insulin resistance, and thermogenesis, indicating that adenosine could participate in the process of obesity. Since adenosine seems to be associated with several effects, it is plausible that adenosine participates in the initiation and development of obesity or may function to prevent it. Thus, the purpose of this review was to explore the involvement of adenosine in adipogenesis, insulin resistance and thermogenesis, with the aim of understanding how adenosine could be used to avoid, treat or improve the metabolic state of obesity. Treatment with specific agonists and/or antagonists of adenosine receptors could reverse the obesity state, since adenosine receptors normalizes several mechanisms involved in obesity, such as lipolysis, insulin sensitivity and thermogenesis. Furthermore, obesity is a preventable state, and the specific activation of adenosine receptors could aid in the prevention of obesity. Nevertheless, for the treatment of obesity and its consequences, more studies and therapeutic strategies in addition to adenosine are necessary.
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Affiliation(s)
- Fabián Pardo
- Metabolic Diseases Research Laboratory, Center of Research, Development and Innovation in Health - Aconcagua Valley, San Felipe Campus, School of Medicine, Faculty of Medicine, Universidad de Valparaiso, 2172972 San Felipe, Chile; Cellular and Molecular Physiology Laboratory, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile.
| | - Roberto Villalobos-Labra
- Cellular and Molecular Physiology Laboratory, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Delia I Chiarello
- Cellular and Molecular Physiology Laboratory, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Rocío Salsoso
- Cellular and Molecular Physiology Laboratory, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain
| | - Fernando Toledo
- Cellular and Molecular Physiology Laboratory, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Basic Sciences, Faculty of Sciences, Universidad del Bío-Bío, Chillán 3780000, Chile
| | - Jaime Gutierrez
- Cellular and Molecular Physiology Laboratory, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Cellular Signaling Differentiation and Regeneration Laboratory, Health Sciences Faculty, Universidad San Sebastian, Santiago, Chile
| | - Andrea Leiva
- Cellular and Molecular Physiology Laboratory, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain; University of Queensland Centre for Clinical Research, Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, QLD 4029, Queensland, Australia.
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Bartness TJ, Liu Y, Shrestha YB, Ryu V. Neural innervation of white adipose tissue and the control of lipolysis. Front Neuroendocrinol 2014; 35:473-93. [PMID: 24736043 PMCID: PMC4175185 DOI: 10.1016/j.yfrne.2014.04.001] [Citation(s) in RCA: 219] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 03/10/2014] [Accepted: 04/04/2014] [Indexed: 01/22/2023]
Abstract
White adipose tissue (WAT) is innervated by the sympathetic nervous system (SNS) and its activation is necessary for lipolysis. WAT parasympathetic innervation is not supported. Fully-executed SNS-norepinephrine (NE)-mediated WAT lipolysis is dependent on β-adrenoceptor stimulation ultimately hinging on hormone sensitive lipase and perilipin A phosphorylation. WAT sympathetic drive is appropriately measured electrophysiologically and neurochemically (NE turnover) in non-human animals and this drive is fat pad-specific preventing generalizations among WAT depots and non-WAT organs. Leptin-triggered SNS-mediated lipolysis is weakly supported, whereas insulin or adenosine inhibition of SNS/NE-mediated lipolysis is strongly supported. In addition to lipolysis control, increases or decreases in WAT SNS drive/NE inhibit and stimulate white adipocyte proliferation, respectively. WAT sensory nerves are of spinal-origin and sensitive to local leptin and increases in sympathetic drive, the latter implicating lipolysis. Transsynaptic viral tract tracers revealed WAT central sympathetic and sensory circuits including SNS-sensory feedback loops that may control lipolysis.
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Affiliation(s)
- Timothy J Bartness
- Department of Biology, Center for Obesity Reversal, Georgia State University, Atlanta, GA 30302-4010, USA; Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30302-4010, USA.
| | - Yang Liu
- Department of Biology, Center for Obesity Reversal, Georgia State University, Atlanta, GA 30302-4010, USA; Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30302-4010, USA; Metabolic Diseases Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yogendra B Shrestha
- Metabolic Diseases Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Vitaly Ryu
- Department of Biology, Center for Obesity Reversal, Georgia State University, Atlanta, GA 30302-4010, USA; Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30302-4010, USA; Metabolic Diseases Branch, NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
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9
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Nielsen TS, Jessen N, Jørgensen JOL, Møller N, Lund S. Dissecting adipose tissue lipolysis: molecular regulation and implications for metabolic disease. J Mol Endocrinol 2014; 52:R199-222. [PMID: 24577718 DOI: 10.1530/jme-13-0277] [Citation(s) in RCA: 263] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Lipolysis is the process by which triglycerides (TGs) are hydrolyzed to free fatty acids (FFAs) and glycerol. In adipocytes, this is achieved by sequential action of adipose TG lipase (ATGL), hormone-sensitive lipase (HSL), and monoglyceride lipase. The activity in the lipolytic pathway is tightly regulated by hormonal and nutritional factors. Under conditions of negative energy balance such as fasting and exercise, stimulation of lipolysis results in a profound increase in FFA release from adipose tissue (AT). This response is crucial in order to provide the organism with a sufficient supply of substrate for oxidative metabolism. However, failure to efficiently suppress lipolysis when FFA demands are low can have serious metabolic consequences and is believed to be a key mechanism in the development of type 2 diabetes in obesity. As the discovery of ATGL in 2004, substantial progress has been made in the delineation of the remarkable complexity of the regulatory network controlling adipocyte lipolysis. Notably, regulatory mechanisms have been identified on multiple levels of the lipolytic pathway, including gene transcription and translation, post-translational modifications, intracellular localization, protein-protein interactions, and protein stability/degradation. Here, we provide an overview of the recent advances in the field of AT lipolysis with particular focus on the molecular regulation of the two main lipases, ATGL and HSL, and the intracellular and extracellular signals affecting their activity.
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Affiliation(s)
- Thomas Svava Nielsen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, DenmarkThe Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Niels Jessen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, DenmarkThe Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Jens Otto L Jørgensen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Niels Møller
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Sten Lund
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
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Burnstock G. Purinergic signalling in endocrine organs. Purinergic Signal 2014; 10:189-231. [PMID: 24265070 PMCID: PMC3944044 DOI: 10.1007/s11302-013-9396-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 01/08/2023] Open
Abstract
There is widespread involvement of purinergic signalling in endocrine biology. Pituitary cells express P1, P2X and P2Y receptor subtypes to mediate hormone release. Adenosine 5'-triphosphate (ATP) regulates insulin release in the pancreas and is involved in the secretion of thyroid hormones. ATP plays a major role in the synthesis, storage and release of catecholamines from the adrenal gland. In the ovary purinoceptors mediate gonadotrophin-induced progesterone secretion, while in the testes, both Sertoli and Leydig cells express purinoceptors that mediate secretion of oestradiol and testosterone, respectively. ATP released as a cotransmitter with noradrenaline is involved in activities of the pineal gland and in the neuroendocrine control of the thymus. In the hypothalamus, ATP and adenosine stimulate or modulate the release of luteinising hormone-releasing hormone, as well as arginine-vasopressin and oxytocin. Functionally active P2X and P2Y receptors have been identified on human placental syncytiotrophoblast cells and on neuroendocrine cells in the lung, skin, prostate and intestine. Adipocytes have been recognised recently to have endocrine function involving purinoceptors.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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Escudero A, Carreño B, Retamal N, Celis C, Castro L, Aguayo C, Acurio J, Escudero C. Elevated concentrations of plasma adenosine in obese children. Biofactors 2012; 38:422-8. [PMID: 22890589 DOI: 10.1002/biof.1039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 07/01/2012] [Accepted: 07/18/2012] [Indexed: 01/19/2023]
Abstract
There are no data regarding adenosine levels in obese children, even though is a ubiquitous molecule implicated in the regulation of lipid metabolism in humans. To determinate whether adenosine plasma levels are related with anthropometric and biochemical markers in children, we studied 51 students belong to Ramon Belmar School in Linares, Chile. Review of clinical data and frequent food questionnaire were taken in order to collect the information. Plasma adenosine levels were measured by high-performance liquid chromatography and biochemical parameters including insulin, glucose, total proteins, and lipid profile by using standard colorimetric assays. Children with detectable (above 0.1 μM) adenosine plasma levels (n = 30; BMI, 22.3 ± 0.7) had higher total cholesterol (P < 0.05); triglycerides (P < 0.01) and LDL-cholesterol (P < 0.05) concentrations than children with undetectable adenosine levels (n = 21; BMI, 23.9 ± 0.61). Among the analyzed variables, only BMI and BMI standard deviation score (BMI-SDS) were positively correlated with adenosine levels. Besides, obese children (n = 10) showed significantly high adenosine levels compared to controls (n = 11; 1.8 ± 0.2 vs. 1.2 ± 0.1 μM/mg protein, respectively. P < 0.05), but not compared to overweight children (n = 9). In conclusion, obesity in children is associated to high adenosine plasma levels. This study opens a new perspective to investigate the role of adenosine in the regulation of lipid metabolism in obese children.
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Affiliation(s)
- Andrea Escudero
- Vascular Physiology Laboratory, Department of Basic Sciences, University of Bío-Bío, Chillán, Chile
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12
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Panchal SK, Wong WY, Kauter K, Ward LC, Brown L. Caffeine attenuates metabolic syndrome in diet-induced obese rats. Nutrition 2012; 28:1055-62. [PMID: 22721876 DOI: 10.1016/j.nut.2012.02.013] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 02/25/2012] [Accepted: 02/25/2012] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Caffeine is a constituent of many non-alcoholic beverages. Pharmacological actions of caffeine include the antagonism of adenosine receptors and the inhibition of phosphodiesterase activity. The A₁ adenosine receptors present on adipocytes are involved in the control of fatty acid uptake and lipolysis. In this study, the effects of caffeine were characterized in a diet-induced metabolic syndrome in rats. METHODS Rats were given a high-carbohydrate, high-fat diet (mainly containing fructose and beef tallow) for 16 wk. The control rats were given a corn starch diet. Treatment groups were given caffeine 0.5 g/kg of food for the last 8 wk of the 16-wk protocol. The structure and function of the heart and the liver were investigated in addition to the metabolic parameters including the plasma lipid components. RESULTS The high-carbohydrate, high-fat diet induced symptoms of metabolic syndrome, including obesity, dyslipidemia, impaired glucose tolerance, decreased insulin sensitivity, and increased systolic blood pressure, associated with the development of cardiovascular remodeling and non-alcoholic steatohepatitis. The treatment with caffeine in the rats fed the high-carbohydrate, high-fat diet decreased body fat and systolic blood pressure, improved glucose tolerance and insulin sensitivity, and attenuated cardiovascular and hepatic abnormalities, although the plasma lipid concentrations were further increased. CONCLUSION Decreased total body fat, concurrent with increased plasma lipid concentrations, reflects the lipolytic effects of caffeine in adipocytes, likely owing to the caffeine antagonism of A₁ adenosine receptors on adipocytes.
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Affiliation(s)
- Sunil K Panchal
- Department of Biological and Physical Sciences, University of Southern Queensland, Toowoomba, Queensland, Australia
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13
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Therapeutic potential of adenosine analogues and conjugates. Pharmacol Rep 2011; 63:601-17. [PMID: 21857072 DOI: 10.1016/s1734-1140(11)70573-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 11/18/2011] [Indexed: 02/08/2023]
Abstract
This review summarizes current knowledge of adenosine analogues and conjugates with promising therapeutic properties. Adenosine is a signaling molecule that triggers numerous physiological responses. It acts through the adenosine receptors (ARs), belonging to the family of G-protein-coupled receptors and widely distributed throughout the body. Moreover, adenosine is involved in key biochemical processes as a part of ATP, the universal energy currency. Thus, compounds that are analogues of adenosine and its conjugates have been extensively studied as potential therapeutics. Many inhibitors of ARs are in clinical trials as promising agents in treatment of inflammation, type 2 diabetes, arrhythmia and as vasodilators used in the myocardial perfusion imaging (MPI) stress test. Furthermore, adenosine analogues revealed high efficacy as enzyme inhibitors, tested for antitrypanosomal action and as bivalent ligands and adenosine-oligoarginine conjugates as inhibitors of protein kinases.
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Liu Q, Hong IP, Ahn MJ, Yoo HS, Han SB, Hwang BY, Lee MK. Anti-adipogenic Activity of Cordyceps militaris in 3T3-L1 Cells. Nat Prod Commun 2011. [DOI: 10.1177/1934578x1100601213] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Inhibition of adipocytes differentiation is suggested to be an important strategy for prevention and/or treatment of obesity. In our present study, Cordyceps militaris showed significant inhibitory activity on adipocyte differentiation in 3T3-L1 preadipocytes as assessed by measuring fat accumulation using Oil Red O staining. Activity-guided fractionation led to the isolation of cordycepin (1), guanosine (2) and tryptophan (3) as active compounds. All the three compounds were more effective in the prevention of early stage of adipogenesis than in lipolysis. In addition, combinational treatment of three compounds significantly increased anti-adipogenic activity.
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Affiliation(s)
- Qing Liu
- College of Pharmacy, Chungbuk National University, Cheongju 361-763, Korea
| | - In Pyo Hong
- National Academy of Agricultural Science, Suwon, Gyunggi 441-707, Korea
| | - Mi-Jeong Ahn
- College of Pharmacy, Gyeongsang National University, Jinju 660-751, Korea
| | - Hwan-Soo Yoo
- College of Pharmacy, Chungbuk National University, Cheongju 361-763, Korea
| | - Sang-Bae Han
- College of Pharmacy, Chungbuk National University, Cheongju 361-763, Korea
| | - Bang Yeon Hwang
- College of Pharmacy, Chungbuk National University, Cheongju 361-763, Korea
| | - Mi Kyeong Lee
- College of Pharmacy, Chungbuk National University, Cheongju 361-763, Korea
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Szkudelski T, Szkudelska K. Short-term effects of palmitate and 2-bromopalmitate on the lipolytic activity of rat adipocytes. Life Sci 2011; 89:450-5. [PMID: 21819998 DOI: 10.1016/j.lfs.2011.07.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 06/01/2011] [Accepted: 07/07/2011] [Indexed: 12/18/2022]
Abstract
AIMS Fatty acids are involved in the regulation of lipolysis in adipocytes; however, this regulatory action is unclear. The present study aimed to determine the short-term influence of palmitate and its non-metabolisable analogue, 2-bromopalmitate, on the lipolytic activity of adipocytes. MAIN METHODS Freshly isolated rat adipocytes were exposed to lipolytic modulators with or without palmitate or 2-bromopalmitate. Glycerol released from cells was determined as an indicator of lipolysis. Moreover, cAMP, ATP and changes in mitochondrial membrane potential were measured in cells treated with 2-bromopalmitate. KEY FINDINGS It was demonstrated that glycerol release from adipocytes incubated with epinephrine alone or epinephrine with insulin was unchanged by palmitate. However, 2-bromopalmitate was found to significantly decrease lipolysis stimulated by epinephrine or dibutyryl-cAMP. The inhibitory effect of 2-bromopalmitate on lipolysis was accompanied by reduced cAMP in adipocytes. Moreover, 2-bromopalmitate diminished hyperpolarisation of the inner mitochondrial membrane. Adipocyte exposure to 2-bromopalmitate also resulted in a substantial ATP depletion. The effects of 2-bromopalmitate on lipolysis and on ATP content were prevented neither by high glucose nor by alanine in the incubation medium. SIGNIFICANCE These findings demonstrate that short-term adipocyte exposure to palmitate disturbs neither the lipolytic action of epinephrine nor the antilipolytic action of insulin. However, 2-bromopalmitate significantly decreases lipolysis probably due to impaired metabolic activity of mitochondria.
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Affiliation(s)
- Tomasz Szkudelski
- Department of Animal Physiology and Biochemistry, Poznan University of Life Sciences, Wolynska 35, 60-637 Poznan, Poland.
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Szkudelski T, Nogowski L, Szkudelska K. Short-term regulation of adiponectin secretion in rat adipocytes. Physiol Res 2011; 60:521-30. [PMID: 21401303 DOI: 10.33549/physiolres.931971] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Adiponectin belongs to the group of biologically active substances secreted by adipocytes and referred to as adipokines. Disturbances in its secretion and/or action are thought to be involved in the pathogenesis of some metabolic diseases. However, regulation of adiponectin secretion is poorly elucidated. In the present study, short-term regulation of adiponectin secretion in primary rat adipocytes was investigated. Isolated rat adipocytes were incubated in Krebs-Ringer buffer containing 5 mM glucose and insulin alone or in the combination with epinephrine, dibutyryl-cAMP, adenosine A(1) receptor antagonist (DPCPX), palmitate, 2-bromopalmitate or inhibitor of mitochondrial electron transport (rotenone). Adipocyte exposure for 2 h to insulin (1-100 nM) significantly increased secretion of adiponectin compared with secretion observed without insulin. Furthermore, secretion of adiponectin from adipocytes incubated with glucose and insulin was reduced by 1 and 2 microM epinephrine, but not by 0.25 and 0.5 microM epinephrine. Under similar conditions, 1 and 2 mM dibutyryl-cAMP substantially diminished secretion of adiponectin, whereas 0.5 mM dibutyryl-cAMP was ineffective. Secretion of adiponectin was found to be effectively decreased by DPCPX. Moreover, adipocyte exposure to rotenone also resulted in a substantial diminution of secretory response of adipocytes incubated for 2 h with glucose and insulin. It was also demonstrated that palmitate and 2-bromopalmitate (0.06-0.5 mM) failed to affect secretion of leptin. The obtained results indicated that in short-term regulation of adiponectin secretion, insulin and epinephrine exert the opposite effects. These effects appeared as early as after 2 h of exposure. Moreover, deprivation of energy or blockade of adenosine action substantially decreased secretion of adiponectin.
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Affiliation(s)
- T Szkudelski
- Department of Animal Physiology and Biochemistry, Poznan University of Life Sciences, Poznan, Poland.
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Beaudoin MS, Graham TE. Methylxanthines and human health: epidemiological and experimental evidence. Handb Exp Pharmacol 2011:509-548. [PMID: 20859811 DOI: 10.1007/978-3-642-13443-2_21] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
When considering methylxanthines and human health, it must be recognized that in many countries most caffeine is consumed as coffee. This is further confounded by the fact that coffee contains many bioactive substances in addition to caffeine; it is rich in phenols (quinides, chlorogenic acid, and lactones) and also has diterpenes (fatty acid esters), potassium, niacin, magnesium, and the vitamin B(3) precursor trigonelline. There is a paradox as consumption of either caffeine or caffeinated coffee results in a marked insulin resistance and yet habitual coffee consumption has repeatedly been reported to markedly reduce the risk for type 2 diabetes. There is strong evidence that caffeine reduces insulin sensitivity in skeletal muscle and this may be due to a combination of direct antagonism of A(1) receptors and indirectly β-adrenergic stimulation as a result of increased sympathetic activity. Caffeine may also induce reduced hepatic glucose output. With the exception of bone mineral, there is little evidence that caffeine impacts negatively on other health issues. Coffee does not increase the risk of cardiovascular diseases or cancers and there is some evidence suggesting a positive relationship for the former and for some cancers, particularly hepatic cancer.
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Affiliation(s)
- Marie-Soleil Beaudoin
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada, N1G 2W1
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Fredholm BB, Johansson S, Wang YQ. Adenosine and the Regulation of Metabolism and Body Temperature. ADVANCES IN PHARMACOLOGY 2011; 61:77-94. [DOI: 10.1016/b978-0-12-385526-8.00003-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Cirsimarin, a potent antilipogenic flavonoid, decreases fat deposition in mice intra-abdominal adipose tissue. Int J Obes (Lond) 2010; 34:1566-75. [PMID: 20458325 DOI: 10.1038/ijo.2010.85] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE We previously reported that the flavonoid cirsimarin exerts in vitro a strong lipolytic activity on isolated adipocytes. This study was therefore designed to evaluate in vivo the effects of cirsimarin on white adipose tissue (WAT) accretion in mice. METHODS Male CD1 mice were injected daily with either vehicle (intraperitoneal (i.p.)) or cirsimarin (25 or 50 mg kg(-1) per day, i.p.) for 18 days. Mice were killed and fat pads weighted. Epididymal fat pads were used for cellularity measurement. Effects of cirsimarin treatment on lipolysis and lipogenesis in WAT were assessed. RESULTS Mice treated with 25 or 50 mg kg(-1) per day cirsimarin showed a decrease in retroperitoneal (-29 and -37% respectively, P<0.005) and epididymal (-25 and -28% respectively, P<0.005) fat pad weights compared with controls. This effect was restricted to intra-abdominal WAT as no difference was noticed for subcutaneous inguinal WAT. The decrease in intra-abdominal WAT accretion was due to a decrease in adipose cell diameter (-5 and -8% for 25 and 50 mg kg(-1) per day cirsimarin, respectively) resulting in a 14 and 35% decrease in adipose cell volume while no change was noticed in total adipocyte number. Direct injection of cirsimarin (50 mg kg(-1)) to rats did not trigger lipolysis. In contrast, cirsimarin showed in vivo as well as in vitro a strong antilipogenic activity, which may be the critical aspect of its effects on fat accretion in mice. The inhibitory concentration 50% of cirsimarin on lipogenic activity in isolated adipocytes was found to be 1.28±0.04 μM. Cirsimarin given orally reduced intra-abdominal fat accretion in mice. CONCLUSION Cirsimarin exerts potent antilipogenic effect and decreases adipose tissue deposition in mice. Cirsimarin could therefore be a potential candidate for the treatment of obesity.
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Lipolysis and lipid mobilization in human adipose tissue. Prog Lipid Res 2009; 48:275-97. [PMID: 19464318 DOI: 10.1016/j.plipres.2009.05.001] [Citation(s) in RCA: 518] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2009] [Revised: 05/04/2009] [Accepted: 05/08/2009] [Indexed: 01/04/2023]
Abstract
Triacylglycerol (TAG) stored in adipose tissue (AT) can be rapidly mobilized by the hydrolytic action of the three main lipases of the adipocyte. The non-esterified fatty acids (NEFA) released are used by other tissues during times of energy deprivation. Until recently hormone-sensitive lipase (HSL) was considered to be the key rate-limiting enzyme responsible for regulating TAG mobilization. A novel lipase named adipose triglyceride lipase/desnutrin (ATGL) has been identified as playing an important role in the control of fat cell lipolysis. Additionally perilipin and other proteins of the surface of the lipid droplets protecting or exposing the TAG core of the droplets to lipases are also potent regulators of lipolysis. Considerable progress has been made in understanding the mechanisms of activation of the various lipases. Lipolysis is under tight hormonal regulation. The best understood hormonal effects on AT lipolysis concern the opposing regulation by insulin and catecholamines. Heart-derived natriuretic peptides (i.e., stored in granules in the atrial and ventricle cardiomyocytes and exerting stimulating effects on diuresis and natriuresis) and numerous autocrine/paracrine factors originating from adipocytes and other cells of the stroma-vascular fraction may also participate in the regulation of lipolysis. Endocrine and autocrine/paracrine factors cooperate and lead to a fine regulation of lipolysis in adipocytes. Age, anatomical site, sex, genotype and species differences all play a part in the regulation of lipolysis. The manipulation of lipolysis has therapeutic potential in the metabolic disorders frequently associated with obesity and probably in several inborn errors of metabolism.
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Dhalla AK, Chisholm JW, Reaven GM, Belardinelli L. A1 adenosine receptor: role in diabetes and obesity. Handb Exp Pharmacol 2009:271-295. [PMID: 19639285 DOI: 10.1007/978-3-540-89615-9_9] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Adenosine mediates its diverse effects via four subtypes (A(1), A(2A), A(2B) and A(3)) of G-protein-coupled receptors. The A(1) adenosine receptor (A(1)AR) subtype is the most extensively studied and is well characterized in various organ systems. The A(1)ARs are highly expressed in adipose tissue, and endogenous adenosine has been shown to tonically activate adipose tissue A(1)ARs. Activation of the A(1)ARs in adipocytes reduces adenylate cyclase and cAMP content and causes inhibition of lipolysis. The role of A(1)ARs in lipolysis has been well characterized by using several selective A(1)AR agonists as well as A(1)AR knockout mice. However, the contribution of A(1)ARs to the regulation of lipolysis in pathological conditions like insulin resistance, diabetes and dyslipidemia, where free fatty acids (FFA) play an important role, has not been well characterized. Pharmacological agents that reduce the release of FFA from adipose tissue and thus the availability of circulating FFA have the potential to be useful for insulin resistance and hyperlipidemia. Toward this goal, several selective and efficacious agonists of the A(1)ARs are now available, and some have entered early-phase clinical trials; however, none have received regulatory approval yet. Here we review the existing knowledge on the role of A(1)ARs in insulin resistance, diabetes and obesity, and the progress made in the development of A(1)AR agonists as antilipolytic agents, including the challenges associated with this approach.
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Affiliation(s)
- Arvinder K Dhalla
- Department of Pharmacological Sciences, CV Therapeutics Inc., Palo Alto, CA 94304, USA.
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Elzein E, Zablocki J. A1adenosine receptor agonists and their potential therapeutic applications. Expert Opin Investig Drugs 2008; 17:1901-10. [DOI: 10.1517/13543780802497284] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Johansson SM, Lindgren E, Yang JN, Herling AW, Fredholm BB. Adenosine A1 receptors regulate lipolysis and lipogenesis in mouse adipose tissue-interactions with insulin. Eur J Pharmacol 2008; 597:92-101. [PMID: 18789919 DOI: 10.1016/j.ejphar.2008.08.022] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 08/10/2008] [Accepted: 08/21/2008] [Indexed: 12/22/2022]
Abstract
Adenosine acting at adenosine A1 receptors is considered to be one major regulator of adipose tissue physiology. We have examined the role of adenosine and its interactions with insulin in adipose tissue by using A1R knock out (-/-) mice. Removal of endogenous adenosine with adenosine deaminase caused lipolysis in A1R (+/+), but not A1R (-/-) adipocytes. The adenosine analogue, 2-chloroadenosine, inhibited noradrenaline-stimulated lipolysis and cAMP accumulation in A1R (+/+), but not in A1R (-/-) adipocytes. Insulin reduces lipolysis and cAMP via another mechanism than adenosine and acted additively, but not synergistically, with adenosine. Plasma levels of free fatty acids, glycerol and triglycerides were significantly lower in A1R (+/+) than in A1R (-/-) mice after administration of an adenosine analogue. 2-chloroadenosine induced lipogenesis in presence of insulin in A1R (+/+), but not in A1R (-/-) adipocytes. There were no changes in mRNA levels for several genes involved in fat synthesis in adipose tissue between genotypes. Body weight was similar in young A1R (+/+) and A1R (-/-) mice, but old male A1R (-/-) mice were heavier than wild type controls. In conclusion, adenosine inhibits lipolysis via the adenosine A1 receptor and other adenosine receptors play no significant role. Adenosine and insulin mediate additive but not synergistic antilipolytic effects and 2-chloroadenosine stimulates lipogenesis via adenosine A1 receptors. Thus deletion of adenosine A1 receptors should increase lipolysis and decrease lipogenesis, but in fact an increased fat mass was observed, indicating that other actions of adenosine A1 receptors, possibly outside adipose tissue, are also important.
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Affiliation(s)
- Stina M Johansson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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Dhalla AK, Santikul M, Smith M, Wong MY, Shryock JC, Belardinelli L. Antilipolytic Activity of a Novel Partial A1Adenosine Receptor Agonist Devoid of Cardiovascular Effects: Comparison with Nicotinic Acid. J Pharmacol Exp Ther 2007; 321:327-33. [PMID: 17204748 DOI: 10.1124/jpet.106.114421] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Elevated lipolysis and circulating free fatty acid (FFA) levels have been linked to the pathogenesis of insulin resistance. A1 adenosine receptor agonists are potent inhibitors of lipolysis. Several A1 agonists have been tested as potential antilipolytic agents; however, their effect on the cardiovascular system remains a potential problem for development of these agents as drugs. In the present study, we report that CVT-3619 [(2-{6-[((1R,2R)-2-hydroxycyclopentyl) amino] purin9-yl} (4S,5 S,2R,3R)5-[(2fluorophenylthio) methyl] oxolane-3,4-diol)], a novel partial A1 receptor agonist, significantly reduces circulating FFA levels without any effect on heart rate and blood pressure in awake rats. Rats were implanted with indwelling arterial and venous cannulas to obtain serial blood samples, record arterial pressure, and administer drug. CVT-3619 decreased FFA levels in a dose-dependent manner at doses from 1 up to 10 mg/kg. The FFA-lowering effect was blocked by the A1 receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine. Triglyceride (TG) levels were also significantly reduced by CVT-3619 treatment in the absence and presence of Triton. Tachyphylaxis of the antilipolytic effect of CVT-3619 (1 mg/kg i.v. bolus) was not observed with three consecutive treatments. An acute reduction of FFA by CVT-3619 was not followed by a rebound increase of FFA as seen with nicotinic acid. The potency of insulin to decrease lipolysis was increased 4-fold (p < 0.01) in the presence of CVT-3619 (0.5 mg/kg). In summary, CVT-3619 is an orally bioavailable A1 agonist that lowers circulating FFA and TG levels by inhibiting lipolysis. CVT-3619 has antilipolytic effects at doses that do not elicit cardiovascular effects.
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Affiliation(s)
- Arvinder K Dhalla
- Department of Pharmacology, CV Therapeutics, Inc., 3172 Porter Drive, Palo Alto, CA 94304, USA.
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Wang M, Fotsch C. Small-Molecule Compounds that Modulate Lipolysis in Adipose Tissue: Targeting Strategies and Molecular Classes. ACTA ACUST UNITED AC 2006; 13:1019-27. [DOI: 10.1016/j.chembiol.2006.09.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Revised: 09/21/2006] [Accepted: 09/22/2006] [Indexed: 12/31/2022]
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Fatholahi M, Xiang Y, Wu Y, Li Y, Wu L, Dhalla AK, Belardinelli L, Shryock JC. A novel partial agonist of the A(1)-adenosine receptor and evidence of receptor homogeneity in adipocytes. J Pharmacol Exp Ther 2006; 317:676-84. [PMID: 16410404 DOI: 10.1124/jpet.105.099119] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study characterizes the receptor binding and functional effects of CVT-3619 [2-{6-[((1R,2R)-2-hydroxycyclopentyl)-amino]purin-9-yl}(4S,5S,2R,3R)-5-[(2-fluorophenylthio)methyl]-oxolane-3,4-diol], a novel N(6)-5' -substituted adenosine analog and A(1) -adenosine receptor (A(1) AdoR) agonist, on rat epididymal and inguinal adipocytes and on the isolated heart and compares these effects with those caused by the full agonist N(6) -cyclopentyladenosine (CPA). In addition, the hypothesis that adipocyte A(1)AdoR are a heterogeneous population with regard to their affinities for ligands was tested. CVT-3619 was 10-100-fold selective for A(1)AdoR versus other AdoR and bound to adipocyte membranes with high (K(H) = 14 nM) and low (K = 5.4 microM) affinities. CVT-3619 reduced cyclic AMP content and release of nonesterified fatty acids from epididymal adipocytes with IC(50) values of 6 and 44 nM, respectively. CVT-3619 was a partial agonist relative to CPA to reduce lipolysis in epididymal and inguinal adipocytes. CVT-3619 did not change atrial rate in rat heart and caused a small (6-ms) prolongation of the stimulus-to-His bundle interval without causing atrioventricular block in guinea pig heart (effects mediated by A(1)AdoR), whereas CPA caused atrioventricular block and near cessation of atrial electrical activity. CVT-3619 increased coronary conductance (effect mediated by A(2A)AdoR) only at concentrations > or =10 microM. Rat epididymal adipocyte A(1)AdoR had similar affinities for the antagonist 8-cyclopentyl-1,3-dipropylxanthine in the presence of three dissimilar A AdoR agonists (2-chloro-N(6) -cyclopentyladenosine, N(6) -sulfophenyladenosine, and N-5' -ethylcarboxamidoadenosine) as determined by Schild analysis. It was concluded that rat epididymal adipocyte A(1)AdoR are a homogeneous receptor population with regard to affinities for ligands and that CVT-3619 is a partial agonist with selectivity for A(1)AdoR and inhibition of lipolysis.
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Affiliation(s)
- Marjan Fatholahi
- CV Therapeutics, Inc., 3172 Porter Drive, Palo Alto, CA 94304, USA
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Fraser H, Gao Z, Ozeck MJ, Belardinelli L. N-[3-(R)-tetrahydrofuranyl]-6-aminopurine riboside, an A1 adenosine receptor agonist, antagonizes catecholamine-induced lipolysis without cardiovascular effects in awake rats. J Pharmacol Exp Ther 2003; 305:225-31. [PMID: 12649373 DOI: 10.1124/jpet.102.046821] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Elevated serum nonesterified free fatty acid (NEFA) concentrations are detrimental to both the mechanical and electrical function of the heart. A(1) adenosine receptor agonists are potent and efficacious inhibitors of lipolysis; however, their cardiovascular effects have limited their use to lower serum NEFA. Our objective was to determine whether the antilipolytic effect of N-[3-(R)-tetrahydrofuranyl]-6-aminopurine riboside (CVT-510), an A(1) agonist, could be distinguished from its bradycardia effect and demonstrated in rats with normal or elevated serum NEFA. Rats were instrumented with telemetry transmitters for continuous recording of heart rate, and catheterized, for delivery of drugs and blood sampling. CVT-510 caused a rapid and sustained dose-dependent decrease in NEFA at doses that did not cause bradycardia (2, 5, and 20 micro g/kg). Significant bradycardia was observed at 50 micro g/kg. Norepinephrine (NE) increased NEFA from 0.5 +/- 0.01 to 0.9 +/- 0.2 mM and this effect lasted for 2 h. CVT-510 (10 micro g/kg) given at 40 min postinjection of NE reversed the rise in NEFA (69% reduction). When CVT-510 (20 micro g/kg) was given 15 min before a 30-min long infusion of NE, the lipolytic response to NE was prevented. To mimic the antilipolytic effect of CVT-510 in awake rats, hearts were perfused with palmitate at concentrations similar to those observed in the in vivo studies (0.8 and 0.2 mM), which decreased myocardial oxygen consumption (MVO(2)) by 11%. Thus, CVT-510 at doses > or =5-fold lower than those that slow heart rate caused a marked and sustained lowering of normal or elevated NEFA, that when mimicked in vitro decreased MVO(2) and would be expected to improve cardiac efficiency.
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