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Hayato R, Matsumoto T, Higure Y. Ca2+ Depletion in the ER Causes Store-Operated Ca2+ Entry via the TRPC6 Channel in Mouse Brown Adipocytes. Physiol Res 2024; 73:69-80. [PMID: 38466006 PMCID: PMC11019620 DOI: 10.33549/physiolres.935071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 10/31/2023] [Indexed: 04/26/2024] Open
Abstract
beta3-adrenergic activation causes Ca2+ release from the mitochondria and subsequent Ca2+ release from the endoplasmic reticulum (ER), evoking store-operated Ca2+ entry (SOCE) due to Ca2+ depletion from the ER in mouse brown adipocytes. In this study, we investigated how Ca2+ depletion from the ER elicits SOCE in mouse brown adipocytes using fluorometry of intracellular Ca2+ concentration ([Ca2+]i). The administration of cyclopiazonic acid (CPA), a reversible sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA) pump blocker in the ER, caused an increase in [Ca2+]i. Moreover, CPA induced SOCE was suppressed by the administration of a Ca2+ free Krebs solution and the transient receptor potential canonical 6 (TRPC6) selective blockers 2-APB, ML-9 and GsMTx-4 but not Pico145, which blocks TRPC1/4/5. Administration of TRPC6 channel agonist 1-oleoyl-2-acetyl-sn-glycerol (OAG) and flufenamic acid elicited Ca2+ entry. Moreover, our RT-PCR analyses detected mRNAs for TRPC6 in brown adipose tissues. In addition, western blot analyses showed the expression of the TRPC6 protein. Thus, TRPC6 is one of the Ca2+ pathways involved in SOCE. These modes of Ca2+ entry provide the basis for heat production via activation of Ca2+-dependent dehydrogenase and the expression of uncoupling protein 1 (UCP1). Enhancing thermogenic metabolism in brown adipocytes may serve as broad therapeutic utility to reduce obesity and metabolic syndrome.
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Affiliation(s)
- R Hayato
- Laboratory of Anatomy and Physiology, School of Nutritional Sciences, Nagoya University of Arts and Sciences, Takenoyama, Nissin-City, Aichi, Japan.
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2
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Nascimento-Viana JB, Alcántara-Hernández R, Oliveira-Barros E, Castello Branco LA, Feijó PR, Soares Romeiro LA, Nasciutti LE, Noël F, García-Sáinz JA, Silva CLM. The α1-adrenoceptor-mediated human hyperplastic prostate cells proliferation is impaired by EGF receptor inhibition. Life Sci 2019; 239:117048. [PMID: 31730867 DOI: 10.1016/j.lfs.2019.117048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 10/24/2019] [Accepted: 11/05/2019] [Indexed: 01/12/2023]
Abstract
Benign prostatic hyperplasia (BPH) is an aging-related and progressive disease linked to an up-regulation of α1-adrenoceptors. The participation of EGF receptors (EGFR) in the GPCRs' signalosome has been described but so far data about the contribution of these receptors to prostatic stromal hyperplasia are scanty. We isolated and cultured vimentin-positive prostate stromal cells obtained from BPH patients. According to intracellular Ca2+ measurements, cell proliferation and Western blotting assays, these cultured hyperplastic stromal cells express functional α1-adrenoceptors and EGFR, and proliferate in response to the α1-adrenoceptor agonist phenylephrine. Interestingly, in these cells the inhibition of EGFR signaling with GM6001, CRM197, AG1478 or PD98059 was associated with full blockage of α1-adrenoceptor-mediated cell proliferation, while cell treatment with each inhibitor alone did not alter basal cell growth. Moreover, the co-incubation of AG1478 (EGFR inhibitor) with α1A/α1D-adrenoceptor antagonists showed no additive inhibitory effect. These findings highlight a putative role of EGFR signaling to α1-adrenoceptor-mediated human prostate hyperplasia, suggesting that the inhibition of this transactivation cascade could be useful to reduce BPH progression.
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Affiliation(s)
| | | | - Eliane Oliveira-Barros
- Cell Biology and Development Research Program, Universidade Federal do Rio de Janeiro, Brazil
| | - Luiza A Castello Branco
- Cell Biology and Development Research Program, Universidade Federal do Rio de Janeiro, Brazil
| | - Priscilla R Feijó
- Laboratory of Biochemical and Molecular Pharmacology, Universidade Federal do Rio de Janeiro, Brazil
| | | | - Luiz Eurico Nasciutti
- Cell Biology and Development Research Program, Universidade Federal do Rio de Janeiro, Brazil
| | - François Noël
- Laboratory of Biochemical and Molecular Pharmacology, Universidade Federal do Rio de Janeiro, Brazil
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3
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Evans BA, Merlin J, Bengtsson T, Hutchinson DS. Adrenoceptors in white, brown, and brite adipocytes. Br J Pharmacol 2019; 176:2416-2432. [PMID: 30801689 DOI: 10.1111/bph.14631] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 01/28/2019] [Accepted: 02/11/2019] [Indexed: 01/01/2023] Open
Abstract
Adrenoceptors play an important role in adipose tissue biology and physiology that includes regulating the synthesis and storage of triglycerides (lipogenesis), the breakdown of stored triglycerides (lipolysis), thermogenesis (heat production), glucose metabolism, and the secretion of adipocyte-derived hormones that can control whole-body energy homeostasis. These processes are regulated by the sympathetic nervous system through actions at different adrenoceptor subtypes expressed in adipose tissue depots. In this review, we have highlighted the role of adrenoceptor subtypes in white, brown, and brite adipocytes in both rodents and humans and have included detailed analysis of adrenoceptor expression in human adipose tissue and clonally derived adipocytes. We discuss important considerations when investigating adrenoceptor function in adipose tissue or adipocytes. LINKED ARTICLES: This article is part of a themed section on Adrenoceptors-New Roles for Old Players. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.14/issuetoc.
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Affiliation(s)
- Bronwyn A Evans
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Jon Merlin
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Tore Bengtsson
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden
| | - Dana S Hutchinson
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
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4
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Schnabl K, Westermeier J, Li Y, Klingenspor M. Opposing Actions of Adrenocorticotropic Hormone and Glucocorticoids on UCP1-Mediated Respiration in Brown Adipocytes. Front Physiol 2019; 9:1931. [PMID: 30705635 PMCID: PMC6344423 DOI: 10.3389/fphys.2018.01931] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/21/2018] [Indexed: 12/23/2022] Open
Abstract
Brown fat is a potential target in the treatment of metabolic disorders as recruitment and activation of this thermogenic organ increases energy expenditure and promotes satiation. A large variety of G-protein coupled receptors, known as classical drug targets in pharmacotherapy, is expressed in brown adipocytes. In the present study, we analyzed transcriptome data for the expression of these receptors to identify potential pathways for the recruitment and activation of thermogenic capacity in brown fat. Our analysis revealed 12 Gs-coupled receptors abundantly expressed in murine brown fat. We screened ligands for these receptors in brown adipocytes for their ability to stimulate UCP1-mediated respiration and Ucp1 gene expression. Adrenocorticotropic hormone (ACTH), a ligand for the melanocortin 2 receptor (MC2R), turned out to be the most potent activator of UCP1 whereas its capability to stimulate Ucp1 gene expression was comparably low. Adrenocorticotropic hormone is the glandotropic hormone of the endocrine hypothalamus–pituitary–adrenal-axis stimulating the release of glucocorticoids in response to stress. In primary brown adipocytes ACTH acutely increased the cellular respiration rate similar to isoproterenol, a β-adrenergic receptor agonist. The effect of ACTH on brown adipocyte respiration was mediated via the MC2R as confirmed by using an antagonist. Inhibitor-based studies revealed that ACTH-induced respiration was dependent on protein kinase A and lipolysis, compatible with a rise of intracellular cAMP in response to ACTH. Furthermore, it is dependent on UCP1, as cells from UCP1-knockout mice did not respond. Taken together, ACTH is a non-adrenergic activator of murine brown adipocytes, initiating the canonical adenylyl cyclase–cAMP–protein kinase A-lipolysis-UCP1 pathway, and thus a potential target for the recruitment and activation of thermogenic capacity. Based on these findings in primary cell culture, the physiological significance might be that cold-induced ACTH in concert with norepinephrine released from sympathetic nerves contributes to BAT thermogenesis. Notably, dexamethasone attenuated isoproterenol-induced respiration. This effect increased gradually with the duration of pretreatment. In vivo, glucocorticoid release triggered by ACTH might oppose beta-adrenergic stimulation of metabolic fuel combustion in BAT and limit stress-induced hyperthermia.
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Affiliation(s)
- Katharina Schnabl
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,EKFZ - Else Kröner-Fresenius Zentrum for Nutritional Medicine, Technical University of Munich, Freising, Germany.,ZIEL - Institute for Food & Health, Technical University of Munich, Freising, Germany
| | - Julia Westermeier
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,EKFZ - Else Kröner-Fresenius Zentrum for Nutritional Medicine, Technical University of Munich, Freising, Germany
| | - Yongguo Li
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,EKFZ - Else Kröner-Fresenius Zentrum for Nutritional Medicine, Technical University of Munich, Freising, Germany
| | - Martin Klingenspor
- Chair for Molecular Nutritional Medicine, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany.,EKFZ - Else Kröner-Fresenius Zentrum for Nutritional Medicine, Technical University of Munich, Freising, Germany.,ZIEL - Institute for Food & Health, Technical University of Munich, Freising, Germany
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5
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Nedergaard J, Wang Y, Cannon B. Cell proliferation and apoptosis inhibition: essential processes for recruitment of the full thermogenic capacity of brown adipose tissue. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:51-58. [PMID: 29908367 DOI: 10.1016/j.bbalip.2018.06.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 05/15/2018] [Accepted: 06/11/2018] [Indexed: 12/20/2022]
Abstract
In mice living under normal animal house conditions, the brown adipocytes in classical brown adipose tissue depots are already essentially fully differentiated: UCP1 mRNA and UCP1 protein levels are practically saturated. This means that any further recruitment - in response to cold exposure or any other browning agent - does not result in significant augmentation of these parameters. This may easily be construed to indicate that classical brown adipose tissue cannot be further recruited. However, this is far from the case: the capacity for further recruitment instead lies in the ability of the tissue to increase the number of brown-fat cells, a remarkable and highly controlled physiological recruitment process. We have compiled here the available data concerning the unique ability of norepinephrine to increase cell proliferation and inhibit apoptosis in brown adipocytes. Adrenergically stimulated cell proliferation is fully mediated via β1-adrenoceptors and occurs through activation of stem cells in the tissue; intracellular mediation of the signal involves cAMP and protein kinase A activation, but activation of Erk1/2 is not part of the pathway. Apoptosis inhibition in brown adipocytes is induced by both β- and α1-adrenergic receptors and here the intracellular pathway includes Erk1/2 activation. This unique ability of norepinephrine to increase cell number in an apparently mitogenically dormant tissue provides possibilities to augment the metabolic capacity of brown adipose tissue, also for therapeutic purposes.
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Affiliation(s)
- Jan Nedergaard
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.
| | - Yanling Wang
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Barbara Cannon
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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6
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Agudelo LZ, Ferreira DMS, Cervenka I, Bryzgalova G, Dadvar S, Jannig PR, Pettersson-Klein AT, Lakshmikanth T, Sustarsic EG, Porsmyr-Palmertz M, Correia JC, Izadi M, Martínez-Redondo V, Ueland PM, Midttun Ø, Gerhart-Hines Z, Brodin P, Pereira T, Berggren PO, Ruas JL. Kynurenic Acid and Gpr35 Regulate Adipose Tissue Energy Homeostasis and Inflammation. Cell Metab 2018; 27:378-392.e5. [PMID: 29414686 DOI: 10.1016/j.cmet.2018.01.004] [Citation(s) in RCA: 162] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 11/30/2017] [Accepted: 01/10/2018] [Indexed: 12/28/2022]
Abstract
The role of tryptophan-kynurenine metabolism in psychiatric disease is well established, but remains less explored in peripheral tissues. Exercise training activates kynurenine biotransformation in skeletal muscle, which protects from neuroinflammation and leads to peripheral kynurenic acid accumulation. Here we show that kynurenic acid increases energy utilization by activating G protein-coupled receptor Gpr35, which stimulates lipid metabolism, thermogenic, and anti-inflammatory gene expression in adipose tissue. This suppresses weight gain in animals fed a high-fat diet and improves glucose tolerance. Kynurenic acid and Gpr35 enhance Pgc-1α1 expression and cellular respiration, and increase the levels of Rgs14 in adipocytes, which leads to enhanced beta-adrenergic receptor signaling. Conversely, genetic deletion of Gpr35 causes progressive weight gain and glucose intolerance, and sensitizes to the effects of high-fat diets. Finally, exercise-induced adipose tissue browning is compromised in Gpr35 knockout animals. This work uncovers kynurenine metabolism as a pathway with therapeutic potential to control energy homeostasis.
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Affiliation(s)
- Leandro Z Agudelo
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Duarte M S Ferreira
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Igor Cervenka
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Galyna Bryzgalova
- Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Shamim Dadvar
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Paulo R Jannig
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Amanda T Pettersson-Klein
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Tadepally Lakshmikanth
- Science for Life Laboratory, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden; Department of Newborn Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Elahu G Sustarsic
- Metabolic Receptology, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Margareta Porsmyr-Palmertz
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Jorge C Correia
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Manizheh Izadi
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Vicente Martínez-Redondo
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Per M Ueland
- Department of Clinical Science, University of Bergen, Bergen, Norway; Laboratory of Clinical Biochemistry, Haukeland University Hospital, Bergen, Norway
| | | | - Zachary Gerhart-Hines
- Metabolic Receptology, Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Petter Brodin
- Science for Life Laboratory, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden; Department of Newborn Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Teresa Pereira
- Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Per-Olof Berggren
- Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Jorge L Ruas
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, 17177 Stockholm, Sweden.
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7
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Lai W, Cai Y, Zhou J, Chen S, Qin C, Yang C, Liu J, Xie X, Du C. Deficiency of the G protein Gαq ameliorates experimental autoimmune encephalomyelitis with impaired DC-derived IL-6 production and Th17 differentiation. Cell Mol Immunol 2017; 14:557-567. [PMID: 28216651 DOI: 10.1038/cmi.2016.65] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 11/03/2016] [Accepted: 11/03/2016] [Indexed: 12/26/2022] Open
Abstract
Many G protein-coupled receptors (GPCRs) are reported to be involved in the pathogenesis of multiple sclerosis (MS), and ~40% of all identified GPCRs rely on the Gαq/11 G protein family to stimulate inositol lipid signaling. However, the function of Gα subunits in MS pathogenesis is still unknown. In this study, we attempted to determine the role of Gαq in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), a well-known mouse model of MS. We discovered that compared with wild-type mice, Gαq-knockout mice exhibited less severe EAE symptoms, with lower clinical scores, reduced leukocyte infiltration and less extensive demyelination. Moreover, a significantly lower percentage of Th17 cells, one of the key players in MS pathogenesis, was observed in Gαq-knockout EAE mice. Studies in vitro demonstrated that deficiency of Gαq in CD4+ T cells directly impaired Th17 differentiation. In addition, deficiency of Gαq significantly impaired DC-derived IL-6 production, thus inhibiting Th17 differentiation and the Gαq-PLCβ-PKC and Gαq-MAPKs signaling pathways involved in the reduced IL-6 production by DCs. In summary, our data highlighted the critical role of Gαq in regulating Th17 differentiation and MS pathogenesis.
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Affiliation(s)
- Weiming Lai
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Yingying Cai
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Jinfeng Zhou
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Shuai Chen
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Chaoyan Qin
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Cuixia Yang
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Junling Liu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xin Xie
- National Center for Drug Screening, CAS Key Laboratory of Receptor Research, Chinese Academy of Sciences, Shanghai Institute of Materia Medica, Shanghai 201203, China
| | - Changsheng Du
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China.,Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
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8
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Pradhan RN, Zachara M, Deplancke B. A systems perspective on brown adipogenesis and metabolic activation. Obes Rev 2017; 18 Suppl 1:65-81. [PMID: 28164456 DOI: 10.1111/obr.12512] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 12/12/2016] [Indexed: 12/31/2022]
Abstract
Brown adipocytes regulate energy expenditure via mitochondrial uncoupling. This makes these fat cells attractive therapeutic targets to tackle the burgeoning issue of obesity, which itself is coupled to insulin resistance, type 2 diabetes, cardiovascular and fatty liver disease. Recent research has revealed a complex network underlying brown fat cell differentiation and thermogenic activation, involving secreted factors, signal transduction, metabolic pathways and gene regulatory components. Given that brown fat is now reported to be present in adult humans, it is desirable to harness the knowledge from each network module to design effective therapeutic strategies. In this review, we will present a systems perspective on brown adipogenesis and the subsequent metabolic activation of brown adipocytes by integrating signaling, metabolic and gene regulatory modules with a specific focus on known 'druggable' targets within each module.
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Affiliation(s)
- R N Pradhan
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - M Zachara
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - B Deplancke
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
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9
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The Gq signalling pathway inhibits brown and beige adipose tissue. Nat Commun 2016; 7:10895. [PMID: 26955961 PMCID: PMC4786868 DOI: 10.1038/ncomms10895] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 02/01/2016] [Indexed: 12/31/2022] Open
Abstract
Brown adipose tissue (BAT) dissipates nutritional energy as heat via the uncoupling protein-1 (UCP1) and BAT activity correlates with leanness in human adults. Here we profile G protein-coupled receptors (GPCRs) in brown adipocytes to identify druggable regulators of BAT. Twenty-one per cent of the GPCRs link to the Gq family, and inhibition of Gq signalling enhances differentiation of human and murine brown adipocytes. In contrast, activation of Gq signalling abrogates brown adipogenesis. We further identify the endothelin/Ednra pathway as an autocrine activator of Gq signalling in brown adipocytes. Expression of a constitutively active Gq protein in mice reduces UCP1 expression in BAT, whole-body energy expenditure and the number of brown-like/beige cells in white adipose tissue (WAT). Furthermore, expression of Gq in human WAT inversely correlates with UCP1 expression. Thus, our data indicate that Gq signalling regulates brown/beige adipocytes and inhibition of Gq signalling may be a novel therapeutic approach to combat obesity.
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10
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Protein kinase a-mediated cell proliferation in brown preadipocytes is independent of Erk1/2, PI3K and mTOR. Exp Cell Res 2014; 328:143-155. [PMID: 25102377 DOI: 10.1016/j.yexcr.2014.07.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 07/18/2014] [Accepted: 07/22/2014] [Indexed: 02/03/2023]
Abstract
The physiological agonist norepinephrine promotes cell proliferation of brown preadipocytes during the process of tissue recruitment. In a primary culture system, cAMP mediates these adrenergic effects. In the present study, we demonstrated that, in contrast to other systems where the mitogenic effect of cAMP requires the synergistic action of (serum) growth factors, especially insulin/IGF, the cAMP effect in brown preadipocytes was independent of serum and insulin. Protein kinase A, rather than Epac, mediated the cAMP mitogenic effect. The Erk 1/2 family of MAPK, the PI3K system and the mTOR complexes were all activated by cAMP, but these activations were not necessary for cAMP-induced cell proliferation; a protein kinase C isoform may be involved in mediating cAMP-activated cell proliferation. We conclude that the generally acknowledged cellular mediators for induction of cell proliferation are not involved in this process in the brown preadipocyte system; this conclusion may be of relevance both for examination of mechanisms for induction of brown adipose tissue recruitment but also for understanding the mechanism behind e.g. certain endocrine neoplasias.
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