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Gaziano I, Corneliussen S, Biglari N, Neuhaus R, Shen L, Sotelo-Hitschfeld T, Klemm P, Steuernagel L, De Solis AJ, Chen W, Wunderlich FT, Kloppenburg P, Brüning JC. Dopamine-inhibited POMCDrd2+ neurons in the ARC acutely regulate feeding and body temperature. JCI Insight 2022; 7:162753. [PMID: 36345942 PMCID: PMC9675440 DOI: 10.1172/jci.insight.162753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 09/16/2022] [Indexed: 11/09/2022] Open
Abstract
Dopamine acts on neurons in the arcuate nucleus (ARC) of the hypothalamus, which controls homeostatic feeding responses. Here we demonstrate a differential enrichment of dopamine receptor 1 (Drd1) expression in food intake-promoting agouti related peptide (AgRP)/neuropeptide Y (NPY) neurons and a large proportion of Drd2-expressing anorexigenic proopiomelanocortin (POMC) neurons. Owing to the nature of these receptors, this translates into a predominant activation of AgRP/NPY neurons upon dopamine stimulation and a larger proportion of dopamine-inhibited POMC neurons. Employing intersectional targeting of Drd2-expressing POMC neurons, we reveal that dopamine-mediated POMC neuron inhibition is Drd2 dependent and that POMCDrd2+ neurons exhibit differential expression of neuropeptide signaling mediators compared with the global POMC neuron population, which manifests in enhanced somatostatin responsiveness of POMCDrd2+ neurons. Selective chemogenetic activation of POMCDrd2+ neurons uncovered their ability to acutely suppress feeding and to preserve body temperature in fasted mice. Collectively, the present study provides the molecular and functional characterization of POMCDrd2+ neurons and aids our understanding of dopamine-dependent control of homeostatic energy-regulatory neurocircuits.
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Affiliation(s)
- Isabella Gaziano
- Neuronal Control of Metabolism group, Max Planck Institute for Metabolism Research, Cologne, Germany.,Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.,Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and
| | - Svenja Corneliussen
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and,Institute for Zoology, Faculty of Mathematics and Natural Sciences, University of Cologne, Germany
| | - Nasim Biglari
- Neuronal Control of Metabolism group, Max Planck Institute for Metabolism Research, Cologne, Germany.,Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.,Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and
| | - René Neuhaus
- Neuronal Control of Metabolism group, Max Planck Institute for Metabolism Research, Cologne, Germany.,Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.,Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and
| | - Linyan Shen
- Neuronal Control of Metabolism group, Max Planck Institute for Metabolism Research, Cologne, Germany.,Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.,Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and
| | - Tamara Sotelo-Hitschfeld
- Neuronal Control of Metabolism group, Max Planck Institute for Metabolism Research, Cologne, Germany.,Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.,Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and
| | - Paul Klemm
- Neuronal Control of Metabolism group, Max Planck Institute for Metabolism Research, Cologne, Germany.,Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.,Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and
| | - Lukas Steuernagel
- Neuronal Control of Metabolism group, Max Planck Institute for Metabolism Research, Cologne, Germany.,Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.,Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and
| | - Alain J. De Solis
- Neuronal Control of Metabolism group, Max Planck Institute for Metabolism Research, Cologne, Germany.,Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.,Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and
| | - Weiyi Chen
- Neuronal Control of Metabolism group, Max Planck Institute for Metabolism Research, Cologne, Germany.,Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.,Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and
| | - F. Thomas Wunderlich
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.,Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and,Obesity and Cancer group, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Peter Kloppenburg
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and,Institute for Zoology, Faculty of Mathematics and Natural Sciences, University of Cologne, Germany
| | - Jens C. Brüning
- Neuronal Control of Metabolism group, Max Planck Institute for Metabolism Research, Cologne, Germany.,Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany.,Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center of Molecular Medicine Cologne (CMMC) and,National Center for Diabetes Research (DZD), Neuherberg, Germany
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2
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Zeng W, Yang F, Shen WL, Zhan C, Zheng P, Hu J. Interactions between central nervous system and peripheral metabolic organs. SCIENCE CHINA. LIFE SCIENCES 2022; 65:1929-1958. [PMID: 35771484 DOI: 10.1007/s11427-021-2103-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 04/07/2022] [Indexed: 02/08/2023]
Abstract
According to Descartes, minds and bodies are distinct kinds of "substance", and they cannot have causal interactions. However, in neuroscience, the two-way interaction between the brain and peripheral organs is an emerging field of research. Several lines of evidence highlight the importance of such interactions. For example, the peripheral metabolic systems are overwhelmingly regulated by the mind (brain), and anxiety and depression greatly affect the functioning of these systems. Also, psychological stress can cause a variety of physical symptoms, such as bone loss. Moreover, the gut microbiota appears to play a key role in neuropsychiatric and neurodegenerative diseases. Mechanistically, as the command center of the body, the brain can regulate our internal organs and glands through the autonomic nervous system and neuroendocrine system, although it is generally considered to be outside the realm of voluntary control. The autonomic nervous system itself can be further subdivided into the sympathetic and parasympathetic systems. The sympathetic division functions a bit like the accelerator pedal on a car, and the parasympathetic division functions as the brake. The high center of the autonomic nervous system and the neuroendocrine system is the hypothalamus, which contains several subnuclei that control several basic physiological functions, such as the digestion of food and regulation of body temperature. Also, numerous peripheral signals contribute to the regulation of brain functions. Gastrointestinal (GI) hormones, insulin, and leptin are transported into the brain, where they regulate innate behaviors such as feeding, and they are also involved in emotional and cognitive functions. The brain can recognize peripheral inflammatory cytokines and induce a transient syndrome called sick behavior (SB), characterized by fatigue, reduced physical and social activity, and cognitive impairment. In summary, knowledge of the biological basis of the interactions between the central nervous system and peripheral organs will promote the full understanding of how our body works and the rational treatment of disorders. Thus, we summarize current development in our understanding of five types of central-peripheral interactions, including neural control of adipose tissues, energy expenditure, bone metabolism, feeding involving the brain-gut axis and gut microbiota. These interactions are essential for maintaining vital bodily functions, which result in homeostasis, i.e., a natural balance in the body's systems.
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Affiliation(s)
- Wenwen Zeng
- Institute for Immunology, and Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, 100084, China. .,Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China. .,Beijing Key Laboratory for Immunological Research on Chronic Diseases, Beijing, 100084, China.
| | - Fan Yang
- The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, 518055, China.
| | - Wei L Shen
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Cheng Zhan
- Department of Hematology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230026, China. .,National Institute of Biological Sciences, Beijing, 102206, China. .,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China.
| | - Peng Zheng
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400042, China. .,Institute of Neuroscience and the Collaborative Innovation Center for Brain Science, Chongqing Medical University, Chongqing, 400016, China. .,Chongqing Key Laboratory of Neurobiology, Chongqing, 400016, China.
| | - Ji Hu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
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Mahmoudinezhad M, Abbasalizad Farhangi M. Association between Ag-RP, alpha-MSH and cardiovascular risk factors regarding adherence to diet quality index-international (DQI-I) among obese individuals. J Cardiovasc Thorac Res 2021; 13:320-329. [PMID: 35047137 PMCID: PMC8749370 DOI: 10.34172/jcvtr.2021.48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 10/12/2021] [Accepted: 11/04/2021] [Indexed: 11/15/2022] Open
Abstract
Introduction: Obesity is a strong promoter of cardiometabolic risk factors and is associated with several chronic comorbidities. Recently, the role of α-melanocyte stimulating hormone (α-MSH) and agouti related peptide (Ag-RP) in regulation of energy balance has attracted much attention. In current study, we evaluated the association between α-MSH and Ag-RP with cardiometabolic factors among obese individuals with different adherence to Diet Quality Index-International (DQI-I) values.
Methods: In this research, 188 obese adults aged between 20 and 50 years old and body mass index (BMI) between 30 and 40 kg/m2 were recruited. Dietary intakes of participants and DQI-I calculation was performed using a semi-quantitative food frequency questionnaire (FFQ) with 132 food items. Serum glucose, lipids, insulin, and plasma α-MSH and Ag-RP levels were measured using ELISA kits. Homeostasis model assessment for insulin resistance index (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) were also calculated.
Results: Among those with the lowest adherence to DQI-I, Ag-RP was positively associated with systolic blood pressure (SBP) (P = 0.03) among males, which was associated with waist circumference (WC) (P = 0.01) and diastolic blood pressure (DBP) (P = 0.01). Moreover, among males with low and moderate adherence to DQI-I, α-MSH was positively associated with insulin (P = 0.04), weight (P = 0.03), WC (P < 0.01), SDP (P = 0.02) and DBP (P = 0.01). Also, Ag-RP showed a positive association with BMI values (R2 = 0.03; P = 0.03).
Conclusion: According to our findings, in obese subjects with poor to moderate adherence to DQI-I, Ag-RP and α-MSH were in positive correlation with cardiometabolic risk factors. These findings further clarify the clinical importance of these parameters as prognostic factors of cardiometabolic abnormalities.
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Affiliation(s)
- Mahsa Mahmoudinezhad
- Drug Applied Research Center, Department of Community Nutrition, Faculty of Nutrition, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mahdieh Abbasalizad Farhangi
- Drug Applied Research Center, Department of Community Nutrition, Faculty of Nutrition, Tabriz University of Medical Sciences, Tabriz, Iran
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4
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Quiñones M, Hernández-Bautista R, Beiroa D, Heras V, Torres-Leal FL, Lam BYH, Senra A, Fernø J, Gómez-Valadés AG, Schwaninger M, Prevot V, Yeo G, Claret M, López M, Diéguez C, Al-Massadi O, Nogueiras R. Sirt3 in POMC neurons controls energy balance in a sex- and diet-dependent manner. Redox Biol 2021; 41:101945. [PMID: 33744652 PMCID: PMC8005845 DOI: 10.1016/j.redox.2021.101945] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 02/06/2023] Open
Abstract
Sirtuin 3 (SIRT3) is one of the seven mammalian sirtuin homologs of the yeast Sir2 gene that has emerged as an important player in the regulation of energy metabolism in peripheral tissues. However, its role in the hypothalamus has not been explored. Herein, we show that the genetic inhibition of SIRT3 in the hypothalamic arcuate nucleus (ARC) induced a negative energy balance and improvement of several metabolic parameters. These effects are specific for POMC neurons, because ablation of SIRT3 in POMC, but not in AgRP neurons, decreased body weight and adiposity, increased energy expenditure and brown adipose tissue (BAT) activity, and induced browning in white adipose tissue (WAT). Notably, the depletion of SIRT3 in POMC neurons caused these effects in male mice fed a chow diet but failed to affect energy balance in males fed a high fat diet and females under both type of diets. Overall, we provide the first evidence pointing for a key role of SIRT3 in POMC neurons in the regulation of energy balance.
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Affiliation(s)
- Mar Quiñones
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain.
| | - René Hernández-Bautista
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Daniel Beiroa
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Violeta Heras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Francisco L Torres-Leal
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; Metabolic Diseases, Exercise and Nutrition (DOMEN) Research Group, Federal University of Piauí, Teresina, Brazil
| | - Brian Y H Lam
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Ana Senra
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain
| | - Johan Fernø
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
| | - Alicia García Gómez-Valadés
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut D'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), 08036, Barcelona, Spain
| | - Markus Schwaninger
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany
| | - Vincent Prevot
- Univ. Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience & Cognition, UMR-S 1172, European Genomic Institute for Diabetes (EGID), F-59000, Lille, France
| | - Giles Yeo
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Marc Claret
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut D'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), 08036, Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08036, Barcelona, Spain; School of Medicine, Universitat de Barcelona, Barcelona, Spain
| | - Miguel López
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Carlos Diéguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Omar Al-Massadi
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain; Instituto de Investigación Sanitaria de Santiago de Compostela, Complexo Hospitalario Universitario de Santiago (CHUS/SERGAS), Travesía da Choupana S/n, 15706, Santiago de Compostela, Spain.
| | - Ruben Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain; Galician Agency of Innovation (GAIN), Xunta de Galicia, Santiago de Compostela, Spain.
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5
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Central Apolipoprotein A-IV Stimulates Thermogenesis in Brown Adipose Tissue. Int J Mol Sci 2021; 22:ijms22031221. [PMID: 33513710 PMCID: PMC7865537 DOI: 10.3390/ijms22031221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 01/22/2021] [Indexed: 12/30/2022] Open
Abstract
Stimulation of thermogenesis in brown adipose tissue (BAT) could have far-reaching health benefits in combatting obesity and obesity-related complications. Apolipoprotein A-IV (ApoA-IV), produced by the gut and the brain in the presence of dietary lipids, is a well-known short-term satiating protein. While our previous studies have demonstrated reduced diet-induced thermogenesis in ApoA-IV-deficient mice, it is unclear whether this reduction is due to a loss of peripheral or central effects of ApoA-IV. We hypothesized that central administration of ApoA-IV stimulates BAT thermogenesis and that sympathetic and sensory innervation is necessary for this action. To test this hypothesis, mice with unilateral denervation of interscapular BAT received central injections of recombinant ApoA-IV protein or artificial cerebrospinal fluid (CSF). The effects of central ApoA-IV on BAT temperature and thermogenesis in mice with unilateral denervation of the intrascapular BAT were monitored using transponder probe implantation, qPCR, and immunoblots. Relative to CSF, central administration of ApoA-IV significantly increased temperature and UCP expression in BAT. However, all of these effects were significantly attenuated or prevented in mice with unilateral denervation. Together, these results clearly demonstrate that ApoA-IV regulates BAT thermogenesis centrally, and this effect is mediated through sympathetic and sensory nerves.
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Castillo-Armengol J, Barquissau V, Geller S, Ji H, Severi I, Venema W, Fenandez EA, Moret C, Huber K, Leal-Esteban LC, Nasrallah A, Martinez-Carreres L, Niederhäuser G, Seoane-Collazo P, Lagarrigue S, López M, Giordano A, Croizier S, Thorens B, Lopez-Mejia IC, Fajas L. Hypothalamic CDK4 regulates thermogenesis by modulating sympathetic innervation of adipose tissues. EMBO Rep 2020; 21:e49807. [PMID: 32657019 PMCID: PMC7507572 DOI: 10.15252/embr.201949807] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 05/14/2020] [Accepted: 05/28/2020] [Indexed: 01/09/2023] Open
Abstract
This study investigated the role of CDK4 in the oxidative metabolism of brown adipose tissue (BAT). BAT from Cdk4−/− mice exhibited fewer lipids and increased mitochondrial volume and expression of canonical thermogenic genes, rendering these mice more resistant to cold exposure. Interestingly, these effects were not BAT cell‐autonomous but rather driven by increased sympathetic innervation. In particular, the ventromedial hypothalamus (VMH) is known to modulate BAT activation via the sympathetic nervous system. We thus examined the effects of VMH neuron‐specific Cdk4 deletion. These mice display increased sympathetic innervation and enhanced cold tolerance, similar to Cdk4−/− mice, in addition to browning of scWAT. Overall, we provide evidence showing that CDK4 modulates thermogenesis by regulating sympathetic innervation of adipose tissue depots through hypothalamic nuclei, including the VMH. This demonstrates that CDK4 not only negatively regulates oxidative pathways, but also modulates the central regulation of metabolism through its action in the brain.
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Affiliation(s)
| | - Valentin Barquissau
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Sarah Geller
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Honglei Ji
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Ilenia Severi
- Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| | - Wiebe Venema
- Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| | - Eric Aria Fenandez
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Catherine Moret
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Katharina Huber
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | | | - Anita Nasrallah
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | | | - Guy Niederhäuser
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Patricia Seoane-Collazo
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Santiago de Compostela, Spain
| | | | - Miguel López
- NeurObesity Group, Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain.,CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Santiago de Compostela, Spain
| | - Antonio Giordano
- Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| | - Sophie Croizier
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | | | - Lluis Fajas
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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Yu H, Chhabra KH, Thompson Z, Jones GL, Kiran S, Shangguan G, Low MJ. Hypothalamic POMC deficiency increases circulating adiponectin despite obesity. Mol Metab 2020; 35:100957. [PMID: 32244188 PMCID: PMC7082555 DOI: 10.1016/j.molmet.2020.01.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/22/2020] [Accepted: 01/31/2020] [Indexed: 02/06/2023] Open
Abstract
Objective The steep rise in the prevalence of obesity and its related metabolic syndrome have become a major worldwide health concerns. Melanocortin peptides from hypothalamic arcuate nucleus (Arc) POMC neurons induce satiety to limit food intake. Consequently, Arc Pomc-deficient mice (ArcPomc−/−) exhibit hyperphagia and obesity. Previous studies demonstrated that the circulating levels of adiponectin, a protein abundantly produced and secreted by fat cells, negatively correlate with obesity in both rodents and humans. However, we found that ArcPomc−/− mice have increased circulating adiponectin levels despite obesity. Therefore, we investigated the physiological function and underlying mechanisms of hypothalamic POMC in regulating systemic adiponectin levels. Methods Circulating adiponectin was measured in obese ArcPomc−/− mice at ages 4–52 weeks. To determine whether increased adiponectin was a direct result of ArcPomc deficiency or a secondary effect of obesity, we examined plasma adiponectin levels in calorie-restricted mice with or without a history of obesity and in ArcPomc−/− mice before and after genetic restoration of Pomc expression in the hypothalamus. To delineate the mechanisms causing increased adiponectin in ArcPomc−/− mice, we determined sympathetic outflow to adipose tissue by assessing epinephrine, norepinephrine, and tyrosine hydroxylase protein levels and measured the circulating adiponectin in the mice after acute norepinephrine or propranolol treatments. In addition, adiponectin mRNA and protein levels were measured in discrete adipose tissue depots to ascertain which fat depots contributed the most to the high level of adiponectin in the ArcPomc−/− mice. Finally, we generated compound Adiopoq−/−:ArcPomc−/− mice and compared their growth, body composition, and glucose homeostasis to the individual knockout mouse strains and their wild-type controls. Results Obese ArcPomc−/− female mice had unexpectedly increased plasma adiponectin compared to wild-type siblings at all ages greater than 8 weeks. Despite chronic calorie restriction to achieve normal body weights, higher adiponectin levels persisted in the ArcPomc−/− female mice. Genetic restoration of Pomc expression in the Arc or acute treatment of the ArcPomc−/− female mice with melanotan II reduced adiponectin levels to control littermate values. The ArcPomc−/− mice had defective thermogenesis and decreased epinephrine, norepinephrine, and tyrosine hydroxylase protein levels in their fat pads, indicating reduced sympathetic outflow to adipose tissue. Injections of norepinephrine into the ArcPomc−/− female mice reduced circulating adiponectin levels, whereas injections of propranolol significantly increased adiponectin levels. Despite the beneficial effects of adiponectin on metabolism, the deletion of adiponectin alleles in the ArcPomc−/− mice did not exacerbate their metabolic abnormalities. Conclusion In summary, to the best of our knowledge, this study provides the first evidence that despite obesity, the ArcPomc−/− mouse model has high circulating adiponectin levels, which demonstrated that increased fat mass is not necessarily correlated with hypoadiponectinemia. Our investigation also found a previously unknown physiological pathway connecting POMC neurons via the sympathetic nervous system to circulating adiponectin, thereby shedding light on the biological regulation of adiponectin. Obese female hypothalamic-specific Pomc-deficient mice have unexpectedly elevated circulating adiponectin. Restoration of Pomc expression in the hypothalamus reduces plasma adiponectin. Low sympathetic output to subcutaneous fat depots in the Pomc-deficient mice contributes to high adiponectin levels. Deletion of adiponectin in hypothalamic-specific Pomc-deficient mice does not alter their metabolic phenotype.
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Affiliation(s)
- Hui Yu
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA.
| | - Kavaljit H Chhabra
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA; Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Zoe Thompson
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Graham L Jones
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Sylee Kiran
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA; School of Literature, Science, and Arts, University of Michigan, Ann Arbor, MI, USA
| | - Gary Shangguan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA
| | - Malcolm J Low
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, 48105, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
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Pence S, Zhu Q, Binne E, Liu M, Shi H, Lo CC. Reduced Diet-induced Thermogenesis in Apolipoprotein A-IV Deficient Mice. Int J Mol Sci 2019; 20:E3176. [PMID: 31261740 PMCID: PMC6651278 DOI: 10.3390/ijms20133176] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 06/21/2019] [Accepted: 06/25/2019] [Indexed: 12/14/2022] Open
Abstract
In the presence of dietary lipids, both apolipoprotein A-IV (ApoA-IV) production and brown adipose tissue (BAT) thermogenesis are increased. The effect of dietary lipid-induced AproA-IV on BAT thermogenesis and energy expenditure remains unknown. In the present study, we hypothesized that ApoA-IV knockout (ApoA-IV-KO) mice exhibited decreased BAT thermogenesis to affect energy homeostasis. To test this hypothesis, BAT thermogenesis in wildtype (WT) and ApoA-IV-KO mice fed either a standard low-fat chow diet or a high-fat diet (HFD) was investigated. When fed a chow diet, energy expenditure and food intake were comparable between WT and ApoA-IV-KO mice. After 1 week of HFD consumption, ApoA-IV-KO mice had comparable energy intake but produced lower energy expenditure relative to their WT controls in the dark phase. After an acute feeding of dietary lipids or 1-week HFD feeding, ApoA-IV-KO mice produced lower levels of uncoupling protein 1 (UCP1) and exhibited reduced expression of thermogenic genes in the BAT compared with WT controls. In response to cold exposure, however, ApoA-IV-KO mice had comparable energy expenditure and BAT temperature relative to WT mice. Thus, ApoA-IV-KO mice exhibited reduced diet-induced BAT thermogenesis and energy expenditure.
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Affiliation(s)
- Sydney Pence
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Diabetes Institute and Honor Tutorial College, Ohio University, Athens, OH 45701, USA
| | - Qi Zhu
- Department of Biology, Miami University, Oxford, OH 45056, USA
| | - Erin Binne
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Diabetes Institute and Honor Tutorial College, Ohio University, Athens, OH 45701, USA
| | - Min Liu
- Department of Pathology and Laboratory Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH 45215, USA
| | - Haifei Shi
- Department of Biology, Miami University, Oxford, OH 45056, USA
| | - Chunmin C Lo
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Diabetes Institute and Honor Tutorial College, Ohio University, Athens, OH 45701, USA.
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9
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Chen M, Wilson EA, Cui Z, Sun H, Shrestha YB, Podyma B, Le CH, Naglieri B, Pacak K, Gavrilova O, Weinstein LS. G sα deficiency in the dorsomedial hypothalamus leads to obesity, hyperphagia, and reduced thermogenesis associated with impaired leptin signaling. Mol Metab 2019; 25:142-153. [PMID: 31014927 PMCID: PMC6601467 DOI: 10.1016/j.molmet.2019.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 04/08/2019] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE Gsα couples multiple receptors, including the melanocortin 4 receptor (MC4R), to intracellular cAMP generation. Germline inactivating Gsα mutations lead to obesity in humans and mice. Mice with brain-specific Gsα deficiency also develop obesity with reduced energy expenditure and locomotor activity, and impaired adaptive thermogenesis, but the underlying mechanisms remain unclear. METHODS We created mice (DMHGsKO) with Gsα deficiency limited to the dorsomedial hypothalamus (DMH) and examined the effects on energy balance and thermogenesis. RESULTS DMHGsKO mice developed severe, early-onset obesity associated with hyperphagia and reduced energy expenditure and locomotor activity, along with impaired brown adipose tissue thermogenesis. Studies in mice with loss of MC4R in the DMH suggest that defective DMH MC4R/Gsα signaling contributes to abnormal energy balance but not to abnormal locomotor activity or cold-induced thermogenesis. Instead, DMHGsKO mice had impaired leptin signaling along with increased expression of the leptin signaling inhibitor protein tyrosine phosphatase 1B in the DMH, which likely contributes to the observed hyperphagia and reductions in energy expenditure, locomotor activity, and cold-induced thermogenesis. CONCLUSIONS DMH Gsα signaling is critical for energy balance, thermogenesis, and leptin signaling. This study provides insight into how distinct signaling pathways can interact to regulate energy homeostasis and temperature regulation.
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Affiliation(s)
- Min Chen
- Metabolic Diseases Branch, Bethesda, MD, 20892, USA.
| | | | - Zhenzhong Cui
- Mouse Metabolism Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
| | - Hui Sun
- Metabolic Diseases Branch, Bethesda, MD, 20892, USA
| | | | | | | | | | - Karel Pacak
- Section on Medical Neuroendocrinology, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Oksana Gavrilova
- Mouse Metabolism Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 20892, USA
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10
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Derghal A, Djelloul M, Azzarelli M, Degonon S, Tourniaire F, Landrier JF, Mounien L. MicroRNAs are involved in the hypothalamic leptin sensitivity. Epigenetics 2018; 13:1127-1140. [PMID: 30395773 DOI: 10.1080/15592294.2018.1543507] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
The central nervous system monitors modifications in metabolic parameters or hormone levels (leptin) and elicits adaptive responses such as food intake and glucose homeostasis regulation. Particularly, within the hypothalamus, pro-opiomelanocortin (POMC) neurons are crucial regulators of energy balance. Consistent with a pivotal role of the melanocortin system in the control of energy homeostasis, disruption of the Pomc gene causes hyperphagia and obesity. Pomc gene expression is tightly controlled by different mechanisms. Interestingly, recent studies pointed to a key role for micro ribonucleic acid (miRNAs) in the regulation of gene expression. However, the role of miRNAs in the leptin sensitivity in hypothalamic melanocortin system has never been assessed. We developed a transgenic mouse model (PDKO) with a partial deletion of the miRNA processing enzyme DICER specifically in POMC neurons. PDKO mice exhibited a normal body weight but a decrease of food intake. Interestingly, PDKO mice had decreased metabolic rate by reduction of VO2 consumption and CO2 production which could explain that PDKO mice have normal weight while eating less. Interestingly, we observed an increase of leptin sensitivity in the POMC neurons of PDKO mice which could explain the decrease of food intake in this model. We also observed an increase in the expression of genes involved in the function of brown adipose tissue that is in polysynaptic contact with the POMC neurons. In summary, these results support the hypothesis that Dicer-derived miRNAs may be involved in the effect of leptin on POMC neurons activity.
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Affiliation(s)
- Adel Derghal
- a Aix Marseille Univ, INSERM, INRA, C2VN , Marseille , France
| | - Mehdi Djelloul
- b Department of Cell and Molecular Biology , Karolinska Institute , Stockholm , Sweden
| | | | | | - Franck Tourniaire
- a Aix Marseille Univ, INSERM, INRA, C2VN , Marseille , France.,c Faculté de Médecine de la Timone , CriBioM, Criblage Biologique Marseille , Marseille , France
| | - Jean-François Landrier
- a Aix Marseille Univ, INSERM, INRA, C2VN , Marseille , France.,c Faculté de Médecine de la Timone , CriBioM, Criblage Biologique Marseille , Marseille , France
| | - Lourdes Mounien
- a Aix Marseille Univ, INSERM, INRA, C2VN , Marseille , France
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11
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Targeting AgRP neurons to maintain energy balance: Lessons from animal models. Biochem Pharmacol 2018; 155:224-232. [PMID: 30012460 DOI: 10.1016/j.bcp.2018.07.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/12/2018] [Indexed: 01/19/2023]
Abstract
The current obesity epidemic is a major worldwide health and economic burden. In the modern environment, an increase in the intake of high-fat and high-sugar foods plays a crucial role in the development of obesity by disrupting the mechanisms governing food intake and energy balance. Food intake and whole-body energy balance are regulated by the central nervous system through a sophisticated neuronal network located mostly in the hypothalamus. In particular, the hypothalamic arcuate nucleus (ARC) is a fundamental center that senses hormonal and nutrient-related signals informing about the energy state of the organism. The ARC contains two small, defined populations of neurons with opposite functions: anorexigenic proopiomelanocortin (POMC)-expressing neurons and orexigenic Agouti-related protein (AgRP)-expressing neurons. AgRP neurons, which also co-produce neuropeptide Y (NPY) and γ-Aminobutyric acid (GABA), are involved in an increase in hunger and a decrease in energy expenditure. In this review, we summarize the key findings from the most common animal models targeting AgRP neurons and the tools used to discern the role of this specific neuronal population in the control of peripheral metabolism, appetite, feeding-related behavior, and other complex behaviors. We also discuss how knowledge gained from these studies has revealed new pathways and key proteins that could be potential therapeutic targets to reduce appetite and food addictions in obesity and other diseases.
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12
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Ye Z, Liu G, Guo J, Su Z. Hypothalamic endoplasmic reticulum stress as a key mediator of obesity-induced leptin resistance. Obes Rev 2018. [PMID: 29514392 DOI: 10.1111/obr.12673] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Obesity is an epidemic disease that is increasing worldwide and is a major risk factor for many metabolic diseases. However, effective agents for the prevention or treatment of obesity remain limited. Therefore, it is urgent to clarify the pathophysiological mechanisms underlying the development and progression of obesity and exploit potential agents to cure and prevent this disease. According to a recent study series, obesity is associated with the development of endoplasmic reticulum stress and the activation of its stress responses (unfolded protein response) in metabolically active tissues, which contribute to the development of obesity-related insulin and leptin resistance, inflammation and energy imbalance. Hypothalamic endoplasmic reticulum stress is the central mechanism underlying the development of obesity-associated leptin resistance and disruption of energy homeostasis; thus, targeting endoplasmic reticulum stress offers a promising therapeutic strategy for improving leptin sensitivity, increasing energy expenditure and ultimately combating obesity. In this review, we highlight the relationship between and mechanism underlying hypothalamic endoplasmic reticulum stress and obesity-associated leptin resistance and energy imbalance and provide new insight regarding strategies for the treatment of obesity.
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Affiliation(s)
- Z Ye
- Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Key Unit of Modulating Liver to Treat Hyperlipemia SATCM (State Administration of Traditional Chinese Medicine), Guangdong Pharmaceutical University, Guangzhou, China.,Guangdong Engineering Research Center of Natural Products and New Drugs, Guangdong Pharmaceutical University, Guangzhou, China
| | - G Liu
- Shenzhen Center for Disease Control and Prevention, Shenzhen, China
| | - J Guo
- Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Key Unit of Modulating Liver to Treat Hyperlipemia SATCM (State Administration of Traditional Chinese Medicine), Guangdong Pharmaceutical University, Guangzhou, China
| | - Z Su
- Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Key Unit of Modulating Liver to Treat Hyperlipemia SATCM (State Administration of Traditional Chinese Medicine), Guangdong Pharmaceutical University, Guangzhou, China.,Guangdong Engineering Research Center of Natural Products and New Drugs, Guangdong Pharmaceutical University, Guangzhou, China
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13
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Stefanidis A, Wiedmann NM, Tyagi S, Allen AM, Watt MJ, Oldfield BJ. Insights into the neurochemical signature of the Innervation of Beige Fat. Mol Metab 2018; 11:47-58. [PMID: 29510909 PMCID: PMC6001285 DOI: 10.1016/j.molmet.2018.01.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 01/17/2018] [Accepted: 01/30/2018] [Indexed: 12/30/2022] Open
Abstract
Objective The potential for brown adipose tissue (BAT) to be targeted as a therapeutic option to combat obesity has been heightened by the discovery of a brown–like form of inducible “beige” adipose tissue in white fat which has overlapping structural and functional properties to “classical” BAT. The likelihood that both beige and brown fat are recruited functionally by neural mechanisms, taken together with the lack of a detailed understanding of the nature of changes in the nervous system when white adipose tissue (WAT) is transformed to brown, provides the impetus for this study. Here, we aim to identify whether there is a shift in the gene expression profile in neurons directly innervating inguinal white adipose tissue (iWAT) that has undergone “beiging” to a signature that is more similar to neurons projecting to BAT. Methods Two groups of rats, one housed at thermoneutrality (27 °C) and the other exposed to cold (8 °C) for 7 days, were killed, and their T13/L1 ganglia, stellate ganglion (T1/T2), or superior cervical ganglion (SCG, C2/3) removed. This approach yielded ganglia containing neurons that innervate either beiged white fat (8 °C for 7 days), inguinal WAT (27 °C for 7 days), BAT (both 27 °C and 8 °C for 7 days) or non-WAT (8 °C for 7 days), the latter included to isolate changes in gene expression that were more aligned with a response to cold exposure than the transformation of white to beige adipocytes. Bioinformatics analyses of RNA sequencing data was performed followed by Ingenuity Pathway Analysis (IPA) to determine differential gene expression and recruitment of biosynthetic pathways. Results When iWAT is “beiged” there is a significant shift in the gene expression profile of neurons in sympathetic ganglia (T13/L1) innervating this depot toward a gene neurochemical signature that is similar to the stellate ganglion projecting to BAT. Bioinformatics analyses of “beiging” related genes revealed upregulation of genes encoding neuropeptides proopiomelanocortin (POMC) and calcitonin-gene related peptide (CGRP) within ganglionic neurons. Treatment of differentiated 3T3L1 adipocytes with αMSH, one of the products cleaved from POMC, results in an elevation in lipolysis and the beiging of these cells as indicated by changes in gene expression markers of browning (Ucp1 and Ppargc1a). Conclusion These data indicate that, coincident with beiging, there is a shift toward a “brown-like” neurochemical signature of postganglionic neurons projecting to inguinal white fat, an increased expression of POMC, and, consistent with a causative role for this prohormone in beiging, an αMSH-mediated increase in beige gene markers in isolated adipocytes. RNA Seq showed shifts in neuronal gene expression following browning of white fat. Gene expression in ganglia projecting to white fat became brown-like with beiging. Bioinformatics analyses revealed neuronal gene candidates associated with beiging. Prominent gene candidates associated with beiging included POMC and CGRP. POMC cleavage product α-MSH caused beiging of cultured fat cells.
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Affiliation(s)
- Aneta Stefanidis
- Department of Physiology, Monash University, Clayton, Victoria, Australia; Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Nicole M Wiedmann
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria, Australia
| | - Sonika Tyagi
- Monash Bioinformatics Platform, Monash University, Clayton, Victoria, Australia
| | - Andrew M Allen
- Department of Physiology, University of Melbourne, Parkville, Victoria, Australia
| | - Matthew J Watt
- Department of Physiology, Monash University, Clayton, Victoria, Australia; Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Brian J Oldfield
- Department of Physiology, Monash University, Clayton, Victoria, Australia; Metabolism, Diabetes and Obesity Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
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14
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Contreras C, Nogueiras R, Diéguez C, Rahmouni K, López M. Traveling from the hypothalamus to the adipose tissue: The thermogenic pathway. Redox Biol 2017; 12:854-863. [PMID: 28448947 PMCID: PMC5406580 DOI: 10.1016/j.redox.2017.04.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/08/2017] [Accepted: 04/11/2017] [Indexed: 01/13/2023] Open
Abstract
Brown adipose tissue (BAT) is a specialized tissue critical for non-shivering thermogenesis producing heat through mitochondrial uncoupling; whereas white adipose tissue (WAT) is responsible of energy storage in the form of triglycerides. Another type of fat has been described, the beige adipose tissue; this tissue emerges in existing WAT depots but with thermogenic ability, a phenomenon known as browning. Several peripheral signals relaying information about energy status act in the brain, particularly the hypothalamus, to regulate thermogenesis in BAT and browning of WAT. Different hypothalamic areas have the capacity to regulate the thermogenic process in brown and beige adipocytes through the sympathetic nervous system (SNS). This review discusses important concepts and discoveries about the central control of thermogenesis as a trip that starts in the hypothalamus, and taking the sympathetic roads to reach brown and beige fat to modulate thermogenic functions.
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Affiliation(s)
- Cristina Contreras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela 15706, Spain.
| | - Rubén Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela 15706, Spain
| | - Carlos Diéguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela 15706, Spain
| | - Kamal Rahmouni
- Department of Pharmacology, University of Iowa, Iowa City, Iowa 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa 52242, USA
| | - Miguel López
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela 15706, Spain.
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15
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Chen M, Shrestha YB, Podyma B, Cui Z, Naglieri B, Sun H, Ho T, Wilson EA, Li YQ, Gavrilova O, Weinstein LS. Gsα deficiency in the dorsomedial hypothalamus underlies obesity associated with Gsα mutations. J Clin Invest 2016; 127:500-510. [PMID: 27991864 DOI: 10.1172/jci88622] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 11/10/2016] [Indexed: 11/17/2022] Open
Abstract
Gsα, encoded by Gnas, mediates hormone and neurotransmitter receptor-stimulated cAMP generation. Heterozygous Gsα-inactivating mutations lead to obesity in Albright hereditary osteodystrophy (AHO) patients, but only when the mutations occur on the maternal allele. This parent-of-origin effect is due to Gsα imprinting in the CNS, although the relevant CNS regions are unknown. We have now shown that mice with a Gnas gene deletion disrupting Gsα expression on the maternal allele, but not the paternal allele, in the dorsomedial nucleus of the hypothalamus (DMH) developed obesity and reduced energy expenditure without hyperphagia. Although maternal Gnas deletion impaired activation of brown adipose tissue (BAT) in mice, their responses to cold environment remained intact. Similar findings were observed in mice with DMH-specific deficiency of melanocortin MC4R receptors, which are known to activate Gsα. Our results show that Gsα imprinting in the DMH underlies the parent-of-origin metabolic phenotype that results from Gsα mutations and that DMH MC4R/Gsα signaling is important for regulation of energy expenditure and BAT activation, but not the metabolic response to cold.
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16
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Contreras C, Nogueiras R, Diéguez C, Medina-Gómez G, López M. Hypothalamus and thermogenesis: Heating the BAT, browning the WAT. Mol Cell Endocrinol 2016; 438:107-115. [PMID: 27498420 DOI: 10.1016/j.mce.2016.08.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/30/2016] [Accepted: 08/01/2016] [Indexed: 12/20/2022]
Abstract
Brown adipose tissue (BAT) has been also considered as the main thermogenic organ responsible of maintenance body temperature through heat production. However, a new type of thermogenic fat has been characterized during the last years, the beige or brite fat, that is developed from white adipose tissue (WAT) in response to different stimuli by a process known as browning. The activities of brown and beige adipocytes ameliorate metabolic disease, including obesity in mice and correlate with leanness in humans. Many genes and pathways that regulate brown and beige adipocyte biology have now been identified, providing a variety of promising therapeutic targets for metabolic disease. The hypothalamus is the main central place orchestrating the outflow signals that drive the sympathetic nerve activity to BAT and WAT, controlling heat production and energy homeostasis. Recent data have revealed new hypothalamic molecular mechanisms, such as hypothalamic AMP-activated protein kinase (AMPK), that control both thermogenesis and browning. This review provides an overview of the factors influencing BAT and WAT thermogenesis, with special focus on the integration of peripheral information on hypothalamic circuits controlling thermoregulation.
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Affiliation(s)
- Cristina Contreras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, 15706, Spain.
| | - Rubén Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, 15706, Spain
| | - Carlos Diéguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, 15706, Spain
| | - Gema Medina-Gómez
- Área de Bioquímica y Biología Molecular, Departamento de Ciencias Básicas de la Salud, Universidad Rey Juan Carlos, 28922, Alcorcón, Madrid, Spain
| | - Miguel López
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, 15706, Spain.
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17
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Abstract
Adipose tissue plays a central role in regulating whole-body energy and glucose homeostasis through its subtle functions at both organ and systemic levels. On one hand, adipose tissue stores energy in the form of lipid and controls the lipid mobilization and distribution in the body. On the other hand, adipose tissue acts as an endocrine organ and produces numerous bioactive factors such as adipokines that communicate with other organs and modulate a range of metabolic pathways. Moreover, brown and beige adipose tissue burn lipid by dissipating energy in the form of heat to maintain euthermia, and have been considered as a new way to counteract obesity. Therefore, adipose tissue dysfunction plays a prominent role in the development of obesity and its related disorders such as insulin resistance, cardiovascular disease, diabetes, depression and cancer. In this review, we will summarize the recent findings of adipose tissue in the control of metabolism, focusing on its endocrine and thermogenic function.
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Affiliation(s)
- Liping Luo
- Department of Metabolism and EndocrinologyMetabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital,
Central South University, Changsha, Hunan, China
| | - Meilian Liu
- Department of Metabolism and EndocrinologyMetabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital,
Central South University, Changsha, Hunan, China
- Department of Biochemistry and Molecular BiologyUniversity of New Mexico Health Sciences Center,
Albuquerque, New Mexico, USA
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18
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Mikulášková B, Maletínská L, Zicha J, Kuneš J. The role of food intake regulating peptides in cardiovascular regulation. Mol Cell Endocrinol 2016; 436:78-92. [PMID: 27450151 DOI: 10.1016/j.mce.2016.07.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 07/07/2016] [Accepted: 07/19/2016] [Indexed: 12/11/2022]
Abstract
Obesity is a risk factor that worsens cardiovascular events leading to higher morbidity and mortality. However, the exact mechanisms of relation between obesity and cardiovascular events are unclear. Nevertheless, it has been demonstrated that pharmacological therapy for obesity has great potential to improve some cardiovascular problems. Therefore, it is important to determine the common mechanisms regulating both food intake and blood pressure. Several hormones produced by peripheral tissues work together with neuropeptides involved in the regulation of both food intake and blood pressure. Anorexigenic (food intake lowering) hormones such as leptin, glucagon-like peptide-1 and cholecystokinin cooperate with α-melanocyte-stimulating hormone, cocaine- and amphetamine-regulated peptide as well as prolactin-releasing peptide. Curiously their collective actions result in increased sympathetic activity, especially in the kidney, which could be one of the factors responsible for the blood pressure increases seen in obesity. On the other hand, orexigenic (food intake enhancing) peptides, especially ghrelin released from the stomach and acting in the brain, cooperates with orexins, neuropeptide Y, melanin-concentrating hormone and galanin, which leads to decreased sympathetic activity and blood pressure. This paradox should be intensively studied in the future. Moreover, it is important to know that the hypothalamus together with the brainstem seem to be major structures in the regulation of food intake and blood pressure. Thus, the above mentioned regions might be essential brain components in the transmission of peripheral signals to the central effects. In this short review, we summarize the current information on cardiovascular effects of food intake regulating peptides.
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Affiliation(s)
- B Mikulášková
- Institute of Physiology AS CR, Prague, Czech Republic; Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic
| | - L Maletínská
- Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic
| | - J Zicha
- Institute of Physiology AS CR, Prague, Czech Republic
| | - J Kuneš
- Institute of Physiology AS CR, Prague, Czech Republic; Institute of Organic Chemistry and Biochemistry AS CR, Prague, Czech Republic.
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19
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Zhu X, Levasseur PR, Michaelis KA, Burfeind KG, Marks DL. A distinct brain pathway links viral RNA exposure to sickness behavior. Sci Rep 2016; 6:29885. [PMID: 27435819 PMCID: PMC4951726 DOI: 10.1038/srep29885] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/23/2016] [Indexed: 11/14/2022] Open
Abstract
Sickness behaviors and metabolic responses to invading pathogens are common to nearly all types of infection. These responses evolved to provide short-term benefit to the host to ward off infection, but impact on quality of life, and when prolonged lead to neurodegeneration, depression, and cachexia. Among the major infectious agents, viruses most frequently enter the brain, resulting in profound neuroinflammation. We sought to define the unique features of the inflammatory response in the brain to these infections. We demonstrate that the molecular pathway defining the central response to dsRNA is distinct from that found in the periphery. The behavioral and physical response to the dsRNA mimetic poly I:C is dependent on signaling via MyD88 when it is delivered centrally, whereas this response is mediated via the TRIF pathway when delivered peripherally. We also define the likely cellular candidates for this MyD88-dependent step. These findings suggest that symptom management is possible without ameliorating protective antiviral immune responses.
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Affiliation(s)
- Xinxia Zhu
- Papé Family Pediatric Research Institute, Oregon Health &Science University, Portland, OR 97239, USA
| | - Pete R Levasseur
- Papé Family Pediatric Research Institute, Oregon Health &Science University, Portland, OR 97239, USA
| | - Katherine A Michaelis
- Papé Family Pediatric Research Institute, Oregon Health &Science University, Portland, OR 97239, USA.,MD/PhD Program, Oregon Health &Science University, Portland, OR 97239, USA
| | - Kevin G Burfeind
- Papé Family Pediatric Research Institute, Oregon Health &Science University, Portland, OR 97239, USA.,MD/PhD Program, Oregon Health &Science University, Portland, OR 97239, USA
| | - Daniel L Marks
- Papé Family Pediatric Research Institute, Oregon Health &Science University, Portland, OR 97239, USA
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Ren H, Cook JR, Kon N, Accili D. Gpr17 in AgRP Neurons Regulates Feeding and Sensitivity to Insulin and Leptin. Diabetes 2015; 64:3670-9. [PMID: 26180086 PMCID: PMC4613971 DOI: 10.2337/db15-0390] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Accepted: 07/05/2015] [Indexed: 12/18/2022]
Abstract
Hypothalamic neurons expressing agouti-related peptide (AgRP) regulate eating and glucose metabolism. Ablation of FOXO1 in AgRP neurons of mice results in reduced food intake, leanness, improved glucose homeostasis, and increased sensitivity to insulin and leptin. We tentatively identified G-protein-coupled receptor Gpr17 as an effector of FOXO1 orexigenic signals in AgRP neurons. In this study, we generated and characterized AgRP neuron-specific Gpr17 knockout mice (Agrp-Gpr17(-/-)) to test the hypothesis that Gpr17 regulates appetite, energy expenditure, and metabolism. Agrp-Gpr17(-/-) mice show reduced food intake, increased relative energy expenditure, and increased satiety, resulting in leanness and reduced body fat. They also show increased central nervous system sensitivity to insulin and leptin and reduced plasma glucose excursions following the administration of glucose or pyruvate. In summary, AgRP neuron-specific Gpr17 knockouts phenocopy FOXO1 knockouts in the same cell type, thus supporting our original hypothesis and providing further impetus to develop Gpr17 antagonists for the treatment of obesity.
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Affiliation(s)
- Hongxia Ren
- Naomi Berrie Diabetes Center and Department of Medicine, Columbia University Medical Center, New York, NY
| | - Joshua R Cook
- Naomi Berrie Diabetes Center and Department of Medicine, Columbia University Medical Center, New York, NY
| | - Ning Kon
- Institute for Cancer Genetics, Columbia University Medical Center, New York, NY
| | - Domenico Accili
- Naomi Berrie Diabetes Center and Department of Medicine, Columbia University Medical Center, New York, NY
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21
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Ruan HB, Dietrich MO, Liu ZW, Zimmer MR, Li MD, Singh JP, Zhang K, Yin R, Wu J, Horvath TL, Yang X. O-GlcNAc transferase enables AgRP neurons to suppress browning of white fat. Cell 2015; 159:306-17. [PMID: 25303527 DOI: 10.1016/j.cell.2014.09.010] [Citation(s) in RCA: 210] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 07/12/2014] [Accepted: 09/02/2014] [Indexed: 01/07/2023]
Abstract
Induction of beige cells causes the browning of white fat and improves energy metabolism. However, the central mechanism that controls adipose tissue browning and its physiological relevance are largely unknown. Here, we demonstrate that fasting and chemical-genetic activation of orexigenic AgRP neurons in the hypothalamus suppress the browning of white fat. O-linked β-N-acetylglucosamine (O-GlcNAc) modification of cytoplasmic and nuclear proteins regulates fundamental cellular processes. The levels of O-GlcNAc transferase (OGT) and O-GlcNAc modification are enriched in AgRP neurons and are elevated by fasting. Genetic ablation of OGT in AgRP neurons inhibits neuronal excitability through the voltage-dependent potassium channel, promotes white adipose tissue browning, and protects mice against diet-induced obesity and insulin resistance. These data reveal adipose tissue browning as a highly dynamic physiological process under central control, in which O-GlcNAc signaling in AgRP neurons is essential for suppressing thermogenesis to conserve energy in response to fasting.
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Affiliation(s)
- Hai-Bin Ruan
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Marcelo O Dietrich
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Neurobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 93042, Brazil
| | - Zhong-Wu Liu
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Marcelo R Zimmer
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 93042, Brazil
| | - Min-Dian Li
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Jay Prakash Singh
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Kaisi Zhang
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Ruonan Yin
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Jing Wu
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Tamas L Horvath
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Neurobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
| | - Xiaoyong Yang
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Section of Comparative Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
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22
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Drougard A, Fournel A, Valet P, Knauf C. Impact of hypothalamic reactive oxygen species in the regulation of energy metabolism and food intake. Front Neurosci 2015; 9:56. [PMID: 25759638 PMCID: PMC4338676 DOI: 10.3389/fnins.2015.00056] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 02/07/2015] [Indexed: 12/31/2022] Open
Abstract
Hypothalamus is a key area involved in the control of metabolism and food intake via the integrations of numerous signals (hormones, neurotransmitters, metabolites) from various origins. These factors modify hypothalamic neurons activity and generate adequate molecular and behavioral responses to control energy balance. In this complex integrative system, a new concept has been developed in recent years, that includes reactive oxygen species (ROS) as a critical player in energy balance. ROS are known to act in many signaling pathways in different peripheral organs, but also in hypothalamus where they regulate food intake and metabolism by acting on different types of neurons, including proopiomelanocortin (POMC) and agouti-related protein (AgRP)/neuropeptide Y (NPY) neurons. Hypothalamic ROS release is under the influence of different factors such as pancreatic and gut hormones, adipokines (leptin, apelin,…), neurotransmitters and nutrients (glucose, lipids,…). The sources of ROS production are multiple including NADPH oxidase, but also the mitochondria which is considered as the main ROS producer in the brain. ROS are considered as signaling molecules, but conversely impairment of this neuronal signaling ROS pathway contributes to alterations of autonomic nervous system and neuroendocrine function, leading to metabolic diseases such as obesity and type 2 diabetes. In this review we focus our attention on factors that are able to modulate hypothalamic ROS release in order to control food intake and energy metabolism, and whose deregulations could participate to the development of pathological conditions. This novel insight reveals an original mechanism in the hypothalamus that controls energy balance and identify hypothalamic ROS signaling as a potential therapeutic strategy to treat metabolic disorders.
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Affiliation(s)
- Anne Drougard
- NeuroMicrobiota, European Associated Laboratory, INSERM/UCL, Institut National de la Santé et de la Recherche Médicale, U1048, Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), CHU Rangueil, Université Paul SabatierToulouse, France
| | | | | | - Claude Knauf
- NeuroMicrobiota, European Associated Laboratory, INSERM/UCL, Institut National de la Santé et de la Recherche Médicale, U1048, Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), CHU Rangueil, Université Paul SabatierToulouse, France
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23
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l-Ornithine intake affects sympathetic nerve outflows and reduces body weight and food intake in rats. Brain Res Bull 2015; 111:48-52. [DOI: 10.1016/j.brainresbull.2014.11.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 11/06/2014] [Accepted: 11/13/2014] [Indexed: 11/17/2022]
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Abstract
The obesity epidemic continues rising as a global health challenge, despite the increasing public awareness and the use of lifestyle and medical interventions. The biomedical community is urged to develop new treatments to obesity. Excess energy is stored as fat in white adipose tissue (WAT), dysfunction of which lies at the core of obesity and associated metabolic disorders. By contrast, brown adipose tissue (BAT) burns fat and dissipates chemical energy as heat. The development and activation of "brown-like" adipocytes, also known as beige cells, result in WAT browning and thermogenesis. The recent discovery of brown and beige adipocytes in adult humans has sparked the exploration of the development, regulation, and function of these thermogenic adipocytes. The central nervous system drives the sympathetic nerve activity in BAT and WAT to control heat production and energy homeostasis. This review provides an overview of the integration of thermal, hormonal, and nutritional information on hypothalamic circuits in thermoregulation.
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Affiliation(s)
- Xiaoyong Yang
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT, USA
- Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
- *Correspondence: Xiaoyong Yang, Section of Comparative Medicine, Yale University School of Medicine, P.O. Box 208016, New Haven, CT 06520-8016, USA,
| | - Hai-Bin Ruan
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT, USA
- Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
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25
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Monge-Roffarello B, Labbe SM, Roy MC, Lemay ML, Coneggo E, Samson P, Lanfray D, Richard D. The PVH as a site of CB1-mediated stimulation of thermogenesis by MC4R agonism in male rats. Endocrinology 2014; 155:3448-58. [PMID: 24949658 DOI: 10.1210/en.2013-2092] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The present study was designed to investigate the involvement of the cannabinoid receptor 1 (CB1) in the stimulating effects of the melanocortin-4 receptor (MC4R) agonism on whole-body and brown adipose tissue (BAT) thermogenesis. In a first series of experiments, whole-body and BAT thermogenesis were investigated in rats infused in the third ventricle of the brain with the MC4R agonist melanotan II (MTII) and the CB1 agonist δ9-tetrahydrocannabinol (δ(9)-THC) or the CB1 antagonist AM251. Whole-body thermogenesis was measured by indirect calorimetry and BAT thermogenesis assessed from interscapular BAT (iBAT) temperature. δ(9)-THC blunted the effects of MTII on energy expenditure and iBAT temperature, whereas AM251 tended to potentiate the MTII effects. δ(9)-THC also blocked the stimulating effect of MTII on (14)C-bromopalmitate and (3)H-deoxyglucose uptakes in iBAT. Additionally, δ(9)-THC attenuated the stimulating effect of MTII on the expression of peroxisome proliferator-activated receptor-γ coactivator 1-α (Pgc1α), type II iodothyronine deiodinase (Dio2), carnitine palmitoyltransferase 1B (Cpt1b), and uncoupling protein 1 (Ucp1). In a second series of experiments, we addressed the involvement of the paraventricular hypothalamic nucleus (PVH) in the CB1-mediated effects of MTII on iBAT thermogenesis, which were assessed following the infusion of MTII in the PVH and δ(9)-THC or AM251 in the fourth ventricle of the brain. We demonstrated the ability of δ(9)-THC to blunt MTII-induced iBAT temperature elevation. δ(9)-THC also blocked the PVH effect of MTII on (14)C-bromopalmitate uptake as well as on Pgc1α and Dio2 expression in iBAT. Altogether the results of this study demonstrate the involvement of the PVH in the CB1-mediated stimulating effects of the MC4R agonist MTII on whole-body and BAT thermogenesis.
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MESH Headings
- Adipose Tissue, Brown/metabolism
- Animals
- Male
- Paraventricular Hypothalamic Nucleus/metabolism
- Peptides, Cyclic/metabolism
- Piperidines
- Pyrazoles
- Rats
- Rats, Wistar
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Melanocortin, Type 4/agonists
- Receptor, Melanocortin, Type 4/metabolism
- Thermogenesis
- alpha-MSH/analogs & derivatives
- alpha-MSH/metabolism
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Affiliation(s)
- Boris Monge-Roffarello
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada G1V 4G5
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26
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Tsuneyama K, Nishida T, Baba H, Taira S, Fujimoto M, Nomoto K, Hayashi S, Miwa S, Nakajima T, Sutoh M, Oda E, Hokao R, Imura J. Neonatal monosodium glutamate treatment causes obesity, diabetes, and macrovesicular steatohepatitis with liver nodules in DIAR mice. J Gastroenterol Hepatol 2014; 29:1736-43. [PMID: 24730643 DOI: 10.1111/jgh.12610] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/06/2014] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND AIM Non-alcoholic steatohepatitis (NASH) is the hepatic manifestation of metabolic syndrome (MS). Monosodium glutamate (MSG)-treated ICR mice is a useful model of MS and NASH, but it shows the different patterns of steatosis from human NASH. Because inbred aged DIAR (ddY, Institute for Animal Reproduction) mice spontaneously show the similar pattern of steatosis as NASH, we analyzed their liver pathology after administering MSG. METHODS MSG-treated DIAR mice (DIAR-MSG) and untreated DIAR mice (DIAR-controls) were sacrificed and assessed histopathologically at 29, 32, 40, 48, and 54 weeks of age. The NASH activity score, body mass index, blood glucose level, and oral glucose tolerance test were also assessed. RESULTS The body mass index and blood glucose levels of DIAR-MSG were significantly higher than controls. The oral glucose tolerance test revealed a type 2 diabetes pattern in DIAR-MSG. The livers of DIAR-MSG mice showed macrovesicular steatosis, lobular inflammation with neutrophils, and ballooning degeneration after 29 weeks. At 54 weeks, mild fibrosis was observed in 5/6 DIAR-MSG and 2/5 DIAR-control mice. In imaging mass spectrometry analysis, cholesterol as well as triglyceride accumulated in the liver of DIAR-MSG mice. Atypical liver nodules were also observed after 32 weeks in DIAR-MSG, some with cellular and structural atypia mimicking human hepatocellular carcinoma. The NASH activity score of DIAR-MSG after 29 weeks was higher than that of control mice, suggesting the development of NASH. CONCLUSIONS DIAR-MSG had NASH-like liver pathology and liver nodules typically associated with MS symptoms. DIAR-MSG provides a valuable animal model to analyze NASH pathogenesis and carcinogenesis.
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Affiliation(s)
- Koichi Tsuneyama
- Department of Diagnostic Pathology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
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27
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Sasaki T, Kikuchi O, Shimpuku M, Susanti VY, Yokota-Hashimoto H, Taguchi R, Shibusawa N, Sato T, Tang L, Amano K, Kitazumi T, Kuroko M, Fujita Y, Maruyama J, Lee YS, Kobayashi M, Nakagawa T, Minokoshi Y, Harada A, Yamada M, Kitamura T. Hypothalamic SIRT1 prevents age-associated weight gain by improving leptin sensitivity in mice. Diabetologia 2014; 57:819-31. [PMID: 24374551 PMCID: PMC3940852 DOI: 10.1007/s00125-013-3140-5] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Accepted: 11/25/2013] [Indexed: 01/10/2023]
Abstract
AIMS/HYPOTHESIS Obesity is associated with ageing and increased energy intake, while restriction of energy intake improves health and longevity in multiple organisms; the NAD(+)-dependent deacetylase sirtuin 1 (SIRT1) is implicated in this process. Pro-opiomelanocortin (POMC) and agouti-related peptide (AgRP) neurons in the arcuate nucleus (ARC) of the hypothalamus are critical for energy balance regulation, and the level of SIRT1 protein decreases with age in the ARC. In the current study we tested whether conditional Sirt1 overexpression in mouse POMC or AgRP neurons prevents age-associated weight gain and diet-induced obesity. METHODS We targeted Sirt1 cDNA sequence into the Rosa26 locus and generated conditional Sirt1 knock-in mice. These mice were crossed with mice harbouring either Pomc-Cre or Agrp-Cre and the metabolic variables, food intake, energy expenditure and sympathetic activity in adipose tissue of the resultant mice were analysed. We also used a hypothalamic cell line to investigate the molecular mechanism by which Sirt1 overexpression modulates leptin signalling. RESULTS Conditional Sirt1 overexpression in mouse POMC or AgRP neurons prevented age-associated weight gain; overexpression in POMC neurons stimulated energy expenditure via increased sympathetic activity in adipose tissue, whereas overexpression in AgRP neurons suppressed food intake. SIRT1 improved leptin sensitivity in hypothalamic neurons in vitro and in vivo by downregulating protein-tyrosine phosphatase 1B, T cell protein-tyrosine phosphatase and suppressor of cytokine signalling 3. However, these phenotypes were absent in mice consuming a high-fat, high-sucrose diet due to decreases in ARC SIRT1 protein and hypothalamic NAD(+) levels. CONCLUSIONS/INTERPRETATION ARC SIRT1 is a negative regulator of energy balance, and decline in ARC SIRT1 function contributes to disruption of energy homeostasis by ageing and diet-induced obesity.
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Affiliation(s)
- Tsutomu Sasaki
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Osamu Kikuchi
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Mayumi Shimpuku
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Vina Yanti Susanti
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Hiromi Yokota-Hashimoto
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Ryo Taguchi
- Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, Maebashi, Gunma Japan
| | - Nobuyuki Shibusawa
- Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, Maebashi, Gunma Japan
| | - Takashi Sato
- Laboratory of Molecular Traffic, Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma Japan
| | - Lijun Tang
- Division of Endocrinology and Metabolism, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi Japan
| | - Kosuke Amano
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Tomoya Kitazumi
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Mitsutaka Kuroko
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Yuki Fujita
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Jun Maruyama
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Yong-soo Lee
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Masaki Kobayashi
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Takashi Nakagawa
- Frontier Research Core for Life Science, University of Toyama, Toyama, Toyama Japan
| | - Yasuhiko Minokoshi
- Division of Endocrinology and Metabolism, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi Japan
| | - Akihiro Harada
- Laboratory of Molecular Traffic, Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma Japan
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Suita, Osaka Japan
| | - Masanobu Yamada
- Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, Maebashi, Gunma Japan
| | - Tadahiro Kitamura
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
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28
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Censani M, Conroy R, Deng L, Oberfield SE, McMahon DJ, Zitsman JL, Leibel RL, Chung WK, Fennoy I. Weight loss after bariatric surgery in morbidly obese adolescents with MC4R mutations. Obesity (Silver Spring) 2014; 22:225-31. [PMID: 23740648 PMCID: PMC3880391 DOI: 10.1002/oby.20511] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/09/2013] [Indexed: 01/13/2023]
Abstract
OBJECTIVE To determine the frequency of Melanocortin 4 Receptor (MC4R) mutations in morbidly obese adolescents undergoing bariatric surgery and compare weight loss outcomes in patients with and without mutations. DESIGN AND METHODS In this prospective cohort study, 135 adolescent patients evaluated for bariatric surgery were screened for MC4R mutations; 56 had 12-month postoperative data available for analysis. RESULTS MC4R mutations were detected in five of the 135 patients (3.7%); four underwent restrictive bariatric surgery. For the three patients with gastric banding, percent excess weight loss (%EWL) postoperatively was 36.0% at 5 years in one, 47% at 4 years in the second, and 85% at 1 year in the third. For the patient with gastric sleeve resection, %EWL of 96% was attained at 1 year postoperatively. The four MC4R cases had a higher, although nonsignificant, %EWL compared to 52 nonmatched controls at 12 months postoperatively (48.6% vs. 23.4%; P < 0.37). When matched by age, sex, and race to 14 controls, there was no significant difference in %EWL (P < 0.31), BMI change (P < 0.27), or absolute weight loss (P < 0.20). CONCLUSION The frequency of MC4R mutations is similar to prior studies, with affected patients showing beneficial weight loss outcomes.
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Affiliation(s)
- Marisa Censani
- Department of Pediatrics, Division of Pediatric Endocrinology, Columbia University Medical Center, New York, NY, United States, 10032
| | - Rushika Conroy
- Department of Pediatrics, Division of Pediatric Endocrinology, Columbia University Medical Center, New York, NY, United States, 10032
| | - Liyong Deng
- Department of Pediatrics, Division of Molecular Genetics, Naomi Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, United States, 10032
| | - Sharon E. Oberfield
- Department of Pediatrics, Division of Pediatric Endocrinology, Columbia University Medical Center, New York, NY, United States, 10032
| | - Donald J. McMahon
- Department of Medicine, Columbia University Medical Center, New York, NY, United States, 10032
| | - Jeffrey L. Zitsman
- Division of Pediatric Surgery, Department of Surgery, Columbia University Medical Center, New York, NY, United States, 10032
| | - Rudy L. Leibel
- Department of Pediatrics, Division of Molecular Genetics, Naomi Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, United States, 10032
- Department of Medicine, Columbia University Medical Center, New York, NY, United States, 10032
| | - Wendy K. Chung
- Department of Pediatrics, Division of Molecular Genetics, Naomi Berrie Diabetes Center, Columbia University College of Physicians and Surgeons, New York, NY, United States, 10032
- Department of Medicine, Columbia University Medical Center, New York, NY, United States, 10032
| | - Ilene Fennoy
- Department of Pediatrics, Division of Pediatric Endocrinology, Columbia University Medical Center, New York, NY, United States, 10032
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29
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Coordinated regulation of hepatic energy stores by leptin and hypothalamic agouti-related protein. J Neurosci 2013; 33:11972-85. [PMID: 23864684 DOI: 10.1523/jneurosci.0830-13.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Like obesity, prolonged food deprivation induces severe hepatic steatosis; however, the functional significance of this phenomenon is not well understood. In this study, we show that the fall in plasma leptin concentration during fasting is required for the development of hepatic steatosis in mice. Removal of leptin receptors from AGRP neurons diminishes fasting-induced hepatic steatosis. Furthermore, the suppressive effects of leptin on fasting-induced hepatic steatosis are absent in mice lacking the gene encoding agouti-related protein (Agrp), suggesting that this function of leptin is mediated by AGRP. Prolonged fasting leads to suppression of hepatic sympathetic activity, increased expression of acyl CoA:diacylglycerol acyltransferase-2 in the liver, and elevation of hepatic triglyceride content and all of these effects are blunted in the absence of AGRP. AGRP deficiency, despite having no effects on feeding or body adiposity in the free-fed state, impairs triglyceride and ketone body release from the liver during prolonged fasting. Furthermore, reducing CNS Agrp expression in wild-type mice by RNAi protected against the development of hepatic steatosis not only during starvation, but also in response to consumption of a high-fat diet. These findings identify the leptin-AGRP circuit as a critical modulator of hepatic triglyceride stores in starvation and suggest a vital role for this circuit in sustaining the supply of energy from the liver to extrahepatic tissues during periods of prolonged food deprivation.
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Tanida M, Yamamoto N, Shibamoto T, Rahmouni K. Involvement of hypothalamic AMP-activated protein kinase in leptin-induced sympathetic nerve activation. PLoS One 2013; 8:e56660. [PMID: 23418591 PMCID: PMC3572050 DOI: 10.1371/journal.pone.0056660] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 01/13/2013] [Indexed: 11/19/2022] Open
Abstract
In mammals, leptin released from the white adipose tissue acts on the central nervous system to control feeding behavior, cardiovascular function, and energy metabolism. Central leptin activates sympathetic nerves that innervate the kidney, adipose tissue, and some abdominal organs in rats. AMP-activated protein kinase (AMPK) is essential in the intracellular signaling pathway involving the activation of leptin receptors (ObRb). We investigated the potential of AMPKα2 in the sympathetic effects of leptin using in vivo siRNA injection to knockdown AMPKα2 in rats, to produce reduced hypothalamic AMPKα2 expression. Leptin effects on body weight, food intake, and blood FFA levels were eliminated in AMPKα2 siRNA-treated rats. Leptin-evoked enhancements of the sympathetic nerve outflows to the kidney, brown and white adipose tissues were attenuated in AMPKα2 siRNA-treated rats. To check whether AMPKα2 was specific to sympathetic changes induced by leptin, we examined the effects of injecting MT-II, a melanocortin-3 and -4 receptor agonist, on the sympathetic nerve outflows to the kidney and adipose tissue. MT-II-induced sympatho-excitation in the kidney was unchanged in AMPKα2 siRNA-treated rats. However, responses of neural activities involving adipose tissue to MT-II were attenuated in AMPKα2 siRNA-treated rats. These results suggest that hypothalamic AMPKα2 is involved not only in appetite and body weight regulation but also in the regulation of sympathetic nerve discharges to the kidney and adipose tissue. Thus, AMPK might function not only as an energy sensor, but as a key molecule in the cardiovascular, thermogenic, and lipolytic effects of leptin through the sympathetic nervous system.
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Affiliation(s)
- Mamoru Tanida
- Department of Physiology II, Kanazawa Medical University, Uchinada, Ishikawa, Japan.
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31
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Abstract
The central melanocortin system plays an essential role in the regulation of energy metabolism. Key to this regulation are the responses of neurons expressing proopiomelanocortin (POMC) and agouti-related protein (AgRP) to blood-borne metabolic signals. Recent evidence has demonstrated that POMC and AgRP neurons are not simply mirror opposites of each other in function and responsiveness to metabolic signals, nor are they exclusively first-order neurons. These neurons act as central transceivers, integrating both hormonal and neural signals, and then transmitting this information to peripheral tissues via the autonomic nervous system to coordinate whole-body energy metabolism. This review focuses on most recent developments obtained from rodent studies on the function, metabolic regulation, and circuitry of the central melanocortin system.
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Affiliation(s)
- James P. Warne
- Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Allison W. Xu
- Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA
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Bartfai T, Conti B. Molecules affecting hypothalamic control of core body temperature in response to calorie intake. Front Genet 2012; 3:184. [PMID: 23097647 PMCID: PMC3466567 DOI: 10.3389/fgene.2012.00184] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 08/31/2012] [Indexed: 01/07/2023] Open
Abstract
Core body temperature (CBT) and calorie intake are main components of energy homeostasis and two important regulators of health, longevity, and aging. In homeotherms, CBT can be influenced by calorie intake as food deprivation or calorie restriction (CR) lowers CBT whereas feeding has hyperthermic effects. The finding that in mice CBT prolonged lifespan independently of CR, suggested that the mechanisms modulating CBT may represent important regulators of aging. Here we summarize the current knowledge on the signaling molecules and their receptors that participate in the regulation of CBT responses to calorie intake. These include hypothalamic neuropeptides regulating feeding but also energy expenditure via modulation of thermogenesis. We also report studies indicating that nutrient signals can contribute to regulation of CBT by direct action on hypothalamic preoptic warm-sensitive neurons that in turn regulate adaptive thermogenesis and hence CBT. Finally, we show the role played by two orphans G protein-coupled receptor: GPR50 and GPR83, that were recently demonstrated to regulate temperature-dependent energy expenditure.
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Affiliation(s)
- Tamas Bartfai
- Department of Chemical Physiology, The Scripps Research Institute La Jolla, CA, USA
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Yasuda T, Masaki T, Gotoh K, Chiba S, Kakuma T, Yoshimatsu H. Intracerebroventricular administration of urotensin II regulates food intake and sympathetic nerve activity in brown adipose tissue. Peptides 2012; 35:131-5. [PMID: 22426154 DOI: 10.1016/j.peptides.2012.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/01/2012] [Accepted: 03/01/2012] [Indexed: 11/24/2022]
Abstract
To clarify the functional roles of urotensin II in regulating energy balance, we investigated the effects of a central infusion of urotensin II on food intake, uncoupling protein (UCP) 1 mRNA expression, temperature, and sympathetic nervous system activity in brown adipose tissue (BAT), a site that regulates energy expenditure in rodents. A bolus central infusion of urotensin II at a dose of 1 nmol/rat into the third cerebral ventricle decreased food intake (p<0.05). Additionally, urotensin II induced c-Fos-like-immunoreactivity (c-FLI) in the paraventricular nucleus (PVN) as compared with that in the control (phosphate buffered saline [PBS]-treated) group. Furthermore, urotensin II increased BAT UCP 1 mRNA expression (p<0.05). Finally, central infusion of urotensin II significantly increased BAT sympathetic nerve activity, which was accompanied by a significant elevation in BAT temperature (p<0.05) in rats. Taken together, central infusion of urotensin II regulates food intake and BAT sympathetic nerve activity in rats.
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Affiliation(s)
- Tohru Yasuda
- Department of Internal Medicine I, Faculty of Medicine, Oita University, 1-1, Idaigaoka, Hasama, Oita 879-5593, Japan
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McAllan L, Cotter PD, Roche HM, Korpela R, Nilaweera KN. Impact of leucine on energy balance. J Physiol Biochem 2012; 69:155-63. [PMID: 22535285 DOI: 10.1007/s13105-012-0170-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 04/10/2012] [Indexed: 12/14/2022]
Abstract
Body weight is determined by the balance between energy intake and energy expenditure. When energy intake exceeds energy expenditure, the surplus energy is stored as fat in the adipose tissue, which causes its expansion and may even lead to the development of obesity. Thus, there is a growing interest to develop dietary interventions that could reduce the current obesity epidemic. In this regard, data from a number of in vivo and in vitro studies suggest that the branched-chain amino acid leucine influences energy balance. However, this has not been consistently reported. Here, we review the literature related to the effects of leucine on energy intake, energy expenditure and lipid metabolism as well as its effects on the cellular activity in the brain (hypothalamus) and in peripheral tissues (gastro-intestinal tract, adipose tissue, liver and muscle) regulating the above physiological processes. Moreover, we discuss how obesity may influence the actions of this amino acid.
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Affiliation(s)
- Liam McAllan
- Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
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35
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Masaki T, Yasuda T, Yoshimatsu H. Apelin-13 microinjection into the paraventricular nucleus increased sympathetic nerve activity innervating brown adipose tissue in rats. Brain Res Bull 2012; 87:540-3. [DOI: 10.1016/j.brainresbull.2012.02.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 02/13/2012] [Accepted: 02/14/2012] [Indexed: 10/28/2022]
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Effects of bezafibrate in nonalcoholic steatohepatitis model mice with monosodium glutamate-induced metabolic syndrome. Eur J Pharmacol 2011; 662:1-8. [PMID: 21549692 DOI: 10.1016/j.ejphar.2011.04.051] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 04/11/2011] [Accepted: 04/18/2011] [Indexed: 12/21/2022]
Abstract
Recently, we reported that monosodium glutamate-treated mice (MSG mice) developed severe hyperlipidemia and diabetes mellitus and several complications of obesity. MSG mice acquired fatty livers and subsequently underwent changes that are characteristic of nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH). In the present study, the effects of bezafibrate on obesity, diabetes mellitus, and NAFLD/NASH were examined in MSG mice. A single dose of MSG (4 mg/g) was administered subcutaneously to neonatal male mice within 24h of birth. Bezafibrate was mixed into the normal feed for 8 weeks. The weight and body mass index of MSG mice increased significantly despite the unchanged intake of food. Triglyceride and total cholesterol levels in blood, visceral adipose tissue, and interscapular adipose tissue rose significantly. In the livers of MSG mice, moderate centrilobular microvesicular steatosis, ballooning degeneration with Mallory bodies, and scattered infiltration of neutrophils and lymphocytes were observed. Centrilobular hepatocytes were 4-hydroxynonenal-positive in MSG mice. Bezafibrate ameliorated the severity of diabetes mellitus, hyperinsulinemia, and hyperlipidemia. Adiponectin and leptin concentrations in blood improved, and the accumulation of visceral fat was inhibited. The expression of acyl-CoA oxidase, a beta-oxidation gene, and carnitine palmitoyl transferase, which regulates lipid metabolism, increased markedly on administration of bezafibrate. The liver pathology in MSG mice also improved with bezafibrate; specifically, macro- and microvesicles in hepatocytes nearly disappeared, and NAFLD activity score improved. It is concluded that bezafibrate inhibits the accumulation of visceral fat, following amelioration of hyperlipidemia, in MSG-induced obese mice, due to improvements in diabetes mellitus, fatty liver, and NAFLD.
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Verty ANA, Allen AM, Oldfield BJ. The endogenous actions of hypothalamic peptides on brown adipose tissue thermogenesis in the rat. Endocrinology 2010; 151:4236-46. [PMID: 20685882 DOI: 10.1210/en.2009-1235] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Although the neuronal pathways within the hypothalamus critical in controlling feeding and energy expenditure and projecting to brown adipose tissue (BAT) have been identified and their peptidergic content characterized, endogenous action of such peptides in the control of BAT activity has not been elucidated. Here male Sprague Dawley rats received infusions of either melanin-concentrating hormone antagonist (SNAP-7941) (1 microg/microl x h), orexin A receptor antagonist (SB-334867-A; 1 microg/microl x h), combined SB-334867-A (1 microg/microl x h), and SNAP-7941 (1 microg/microl x h), or melanocortin-3/4 receptor antagonist (SHU9119) (1 microg/microl x h) via an indwelling cannula in the lateral ventricle attached to s.c. implanted osmotic minipump. BAT temperature, physical activity, body weight, food intake, and changes in uncoupling protein (UCP)-1 were measured. SB-334867-A and SNAP-7941 significantly increased BAT temperature and UCP1 expression and reduced food intake and body weight. Combined infusion of SB-334867-A and SNAP-7941 produced a pronounced response that was greater than the addition of the individual effects in all parameters measured. SHU9119 significantly decreased BAT temperature and UCP1 expression and increased feeding and body weight. In a second series of experiments, the effect of SB-334867-A and SNAP-7941 alone or combination on the expression of the Fos protein was determined. SB-334867-A and SNAP-7941 increased Fos expression in key hypothalamic and brainstem feeding-related regions. In combination, these antagonists produced a greater than additive elevation of Fos expression in most of the regions evaluated. These findings support a role for endogenous orexigenic and anorexigenic hypothalamic peptides acting in concert to create a thermogenic tone via BAT activity.
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MESH Headings
- Adipose Tissue, Brown/metabolism
- Adipose Tissue, Brown/physiology
- Animals
- Benzoxazoles/pharmacology
- Blotting, Western
- Body Weight/drug effects
- Eating/drug effects
- Energy Metabolism/physiology
- Hypothalamic Hormones/antagonists & inhibitors
- Hypothalamic Hormones/metabolism
- Hypothalamic Hormones/physiology
- Ion Channels/metabolism
- Male
- Melanins/antagonists & inhibitors
- Melanins/metabolism
- Melanins/physiology
- Melanocyte-Stimulating Hormones/pharmacology
- Mitochondrial Proteins/metabolism
- Naphthyridines
- Orexin Receptors
- Piperidines/pharmacology
- Pituitary Hormones/antagonists & inhibitors
- Pituitary Hormones/metabolism
- Pituitary Hormones/physiology
- Pyrimidines/pharmacology
- Random Allocation
- Rats
- Rats, Sprague-Dawley
- Receptor, Melanocortin, Type 3/antagonists & inhibitors
- Receptor, Melanocortin, Type 4/antagonists & inhibitors
- Receptors, G-Protein-Coupled/antagonists & inhibitors
- Receptors, Neuropeptide/antagonists & inhibitors
- Thermogenesis/drug effects
- Thermogenesis/physiology
- Uncoupling Protein 1
- Urea/analogs & derivatives
- Urea/pharmacology
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Affiliation(s)
- Aaron N A Verty
- Department of Physiology, Monash University, Clayton, Victoria 3800, Australia
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Mounien L, Marty N, Tarussio D, Metref S, Genoux D, Preitner F, Foretz M, Thorens B. Glut2-dependent glucose-sensing controls thermoregulation by enhancing the leptin sensitivity of NPY and POMC neurons. FASEB J 2010; 24:1747-58. [PMID: 20097878 DOI: 10.1096/fj.09-144923] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The physiological contribution of glucose in thermoregulation is not completely established nor whether this control may involve a regulation of the melanocortin pathway. Here, we assessed thermoregulation and leptin sensitivity of hypothalamic arcuate neurons in mice with inactivation of glucose transporter type 2 (Glut2)-dependent glucose sensing. Mice with inactivation of Glut2-dependent glucose sensors are cold intolerant and show increased susceptibility to food deprivation-induced torpor and abnormal hypothermic response to intracerebroventricular administration of 2-deoxy-d-glucose compared to control mice. This is associated with a defect in regulated expression of brown adipose tissue uncoupling protein I and iodothyronine deiodinase II and with a decreased leptin sensitivity of neuropeptide Y (NPY) and proopiomelanocortin (POMC) neurons, as observed during the unfed-to-refed transition or following i.p. leptin injection. Sites of central Glut-2 expression were identified by a genetic tagging approach and revealed that glucose-sensitive neurons were present in the lateral hypothalamus, the dorsal vagal complex, and the basal medulla but not in the arcuate nucleus. NPY and POMC neurons were, however, connected to nerve terminals from Glut2-expressing neurons. Thus, our data suggest that glucose controls thermoregulation and the leptin sensitivity of NPY and POMC neurons through activation of Glut2-dependent glucose-sensing neurons located outside of the arcuate nucleus.
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Affiliation(s)
- Lourdes Mounien
- Department of Physiology and Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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Veldhuis JD, Bowers CY. Integrating GHS into the Ghrelin System. INTERNATIONAL JOURNAL OF PEPTIDES 2010; 2010:879503. [PMID: 20798846 PMCID: PMC2925380 DOI: 10.1155/2010/879503] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 12/30/2009] [Indexed: 12/21/2022]
Abstract
Oligopeptide derivatives of metenkephalin were found to stimulate growth-hormone (GH) release directly by pituitary somatotrope cells in vitro in 1977. Members of this class of peptides and nonpeptidyl mimetics are referred to as GH secretagogues (GHSs). A specific guanosine triphosphatate-binding protein-associated heptahelical transmembrane receptor for GHS was cloned in 1996. An endogenous ligand for the GHS receptor, acylghrelin, was identified in 1999. Expression of ghrelin and homonymous receptor occurs in the brain, pituitary gland, stomach, endothelium/vascular smooth muscle, pancreas, placenta, intestine, heart, bone, and other tissues. Principal actions of this peptidergic system include stimulation of GH release via combined hypothalamopituitary mechanisms, orexigenesis (appetitive enhancement), insulinostasis (inhibition of insulin secretion), cardiovascular effects (decreased mean arterial pressure and vasodilation), stimulation of gastric motility and acid secretion, adipogenesis with repression of fat oxidation, and antiapoptosis (antagonism of endothelial, neuronal, and cardiomyocyte death). The array of known and proposed interactions of ghrelin with key metabolic signals makes ghrelin and its receptor prime targets for drug development.
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Affiliation(s)
- Johannes D. Veldhuis
- Department of Medicine, Endocrine Research Unit, Mayo School of Graduate Medical Education, Clinical Translational Science Center, Mayo Clinic, Rochester, MN 55905, USA
| | - Cyril Y. Bowers
- Division of Endocrinology, Department of Internal Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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40
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Corander MP, Fenech M, Coll AP. Science of self-preservation: how melanocortin action in the brain modulates body weight, blood pressure, and ischemic damage. Circulation 2009; 120:2260-8. [PMID: 19948994 PMCID: PMC2880450 DOI: 10.1161/circulationaha.109.854612] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Marcus P Corander
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Treatment Centre, Addenbrooke's Hospital, Hills Rd, Cambridge, CB2 0QQ UK
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41
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Clarke IJ, Henry BA. Targeting energy expenditure in muscle as a means of combating obesity. Clin Exp Pharmacol Physiol 2009; 37:121-4. [PMID: 19650796 DOI: 10.1111/j.1440-1681.2009.05259.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
1. To date, an effective therapeutic agent that induces weight loss in obese subjects remains elusive. In order to establish a successful means to combat obesity, it is imperative that we identify novel targets that regulate energy balance. 2. Exciting new data have created resurgence in interest in the role of thermogenesis in energy balance. Recently, it has been demonstrated that functional brown adipocytes are present in adult humans and that brown adipocytes and myocytes are derived from a similar cell lineage and are thus likely to have similar physiological functions. 3. Recent work in the sheep has demonstrated that diffuse fat beds and skeletal muscle exhibit thermogenic properties. Furthermore, in sheep, central administration of leptin markedly increases postprandial thermogenesis in both fat and muscle tissues. This demonstrates that thermogenic processes in skeletal muscle can be manipulated in a similar way to thermogenesis in brown fat. 4. Given that skeletal muscle comprises a significant portion of bodyweight, approximately 30-40% of total body mass, we predict that energy expended by this tissue is likely to have significant ramifications for the regulation of bodyweight. 5. We propose that manipulation of skeletal muscle thermogenesis may provide a novel avenue for the development of anti-obesity therapies.
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Affiliation(s)
- Iain J Clarke
- Department of Physiology, Monash University, Melbourne, Victoria, Australia.
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42
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Garfield AS, Lam DD, Marston OJ, Przydzial MJ, Heisler LK. Role of central melanocortin pathways in energy homeostasis. Trends Endocrinol Metab 2009; 20:203-15. [PMID: 19541496 DOI: 10.1016/j.tem.2009.02.002] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 02/06/2009] [Accepted: 02/06/2009] [Indexed: 02/07/2023]
Abstract
The rise in the global prevalence of human obesity has emphasized the need for a greater understanding of the physiological mechanisms that underlie energy homeostasis. Numerous circulating nutritional cues and central neuromodulatory signals are integrated within the brain to regulate both short- and long-term nutritional state. The central melanocortin system represents a crucial point of convergence for these signals and, thus, has a fundamental role in regulating body weight. The melanocortin ligands, synthesized in discrete neuronal populations within the hypothalamus and brainstem, modulate downstream homeostatic signalling via their action at central melanocortin-3 and -4 receptors. Intimately involved in both ingestive behaviour and energy expenditure, the melanocortin system has garnered much interest as a potential therapeutic target for human obesity.
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Affiliation(s)
- Alastair S Garfield
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
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43
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Song CK, Vaughan CH, Keen-Rhinehart E, Harris RBS, Richard D, Bartness TJ. Melanocortin-4 receptor mRNA expressed in sympathetic outflow neurons to brown adipose tissue: neuroanatomical and functional evidence. Am J Physiol Regul Integr Comp Physiol 2008; 295:R417-28. [PMID: 18550869 DOI: 10.1152/ajpregu.00174.2008] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A precise understanding of neural circuits controlling lipid mobilization and thermogenesis remains to be determined. We have been studying the sympathetic nervous system (SNS) contributions to white adipose tissue (WAT) lipolysis largely in Siberian hamsters. Central melanocortins are implicated in the control of the sympathetic outflow to WAT, and, moreover, the melanocortin 4 receptors (MC4-R) appear to be principally involved. We previously found that acute third ventricular melanotan II (MTII; an MC3/4-R agonist) injections increase sympathetic drive (norepinephrine turnover) to interscapular brown adipose tissue (IBAT) and IBAT temperature. Here we tested whether MC4-R mRNA is expressed in IBAT SNS outflow neurons using in situ hybridization for the former and injections of the transneuronal viral retrograde tract tracer, pseudorabies virus (PRV) into IBAT, for the latter. Significant numbers of double-labeled cells for PRV and MC4-R mRNA were found across the neuroaxis (mean of all brain sites approximately 60%), including the hypothalamic paraventricular nucleus (PVH; approximately 80%). Acute parenchymal MTII microinjections into the PVH of awake, freely-moving hamsters, using doses below those able to increase IBAT temperature when injected into the third ventricle, increased IBAT temperature for as long as 4 h, as measured by temperature transponders implanted below the tissue. Collectively, these data add significant support to the view that central melanocortins are important in controlling IBAT thermogenesis via the SNS innervation of this tissue, likely through the MC4-Rs.
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Affiliation(s)
- C Kay Song
- Department of Biology, Georgia State University, 24 Peachtree Center Ave. NE, Atlanta, GA 30302-4010, USA
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44
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Targeting melanocortin receptors: an approach to treat weight disorders and sexual dysfunction. Nat Rev Drug Discov 2008; 7:307-23. [PMID: 18323849 DOI: 10.1038/nrd2331] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The melanocortin system has multifaceted roles in the control of body weight homeostasis, sexual behaviour and autonomic functions, and so targeting this pathway has immense promise for drug discovery across multiple therapeutic areas. In this Review, we first outline the physiological roles of the melanocortin system, then discuss the potential of targeting melanocortin receptors by using MC3 and MC4 agonists for treating weight disorders and sexual dysfunction, and MC4 antagonists to treat anorectic and cachectic conditions. Given the complexity of the melanocortin system, we also highlight the challenges and opportunities for future drug discovery in this area.
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45
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Dark J, Pelz KM. NPY Y1 receptor antagonist prevents NPY-induced torporlike hypothermia in cold-acclimated Siberian hamsters. Am J Physiol Regul Integr Comp Physiol 2008; 294:R236-45. [DOI: 10.1152/ajpregu.00587.2007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Siberian hamsters ( Phodopus sungorus) undergo bouts of daily torpor during which body temperature decreases by as much as 20°C and provides a significant savings in energy expenditure. Natural torpor in this species is normally triggered by winterlike photoperiods and low ambient temperatures. Intracerebroventricular injection of neuropeptide Y (NPY) reliably induces torporlike hypothermia that resembles natural torpor. NPY-induced torporlike hypothermia is also produced by intracerebroventricular injections of an NPY Y1 receptor agonist but not by injections of an NPY Y5 receptor agonist. In this research, groups of cold-acclimated Siberian hamsters were either coinjected with a Y1 receptor antagonist (1229U91) and NPY or were coinjected with a Y5 receptor antagonist ( CGP71683 ) and NPY in counterbalanced designs. Paired vehicle + NPY induced torporlike hypothermia in 92% of the hamsters, whereas coinjection of Y1 antagonist + NPY induced torporlike hypothermia in 4% of the hamsters. In contrast, paired injections of vehicle + NPY and Y5 antagonist + NPY induced torporlike hypothermia in 100% and 91% of the hamsters, respectively. Although Y5 antagonist treatment alone had no effect on body temperature, Y1 antagonist injections produced hyperthermia compared with controls. Both Y1 antagonist and Y5 antagonist injections significantly reduced food ingestion 24 h after treatment. We conclude that activation of NPY 1 receptors is both sufficient and necessary for NPY-induced torporlike hypothermia.
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46
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Pelz KM, Routman D, Driscoll JR, Kriegsfeld LJ, Dark J. Monosodium glutamate-induced arcuate nucleus damage affects both natural torpor and 2DG-induced torpor-like hypothermia in Siberian hamsters. Am J Physiol Regul Integr Comp Physiol 2008; 294:R255-65. [DOI: 10.1152/ajpregu.00387.2007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Siberian hamsters ( Phodopus sungorus) have the ability to express daily torpor and decrease their body temperature to ∼15°C, providing a significant savings in energy expenditure. Daily torpor in hamsters is cued by winterlike photoperiods and occurs coincident with the annual nadirs in body fat reserves and chronic leptin concentrations. To better understand the neural mechanisms underlying torpor, Siberian hamster pups were postnatally treated with saline or MSG to ablate arcuate nucleus neurons that likely possess leptin receptors. Body temperature was studied telemetrically in cold-acclimated (10°C) male and female hamsters moved to a winterlike photoperiod (10:14-h light-dark cycle) ( experiments 1 and 2) or that remained in a summerlike photoperiod (14:10-h light-dark cycle) ( experiment 3). In experiment 1, even though other photoperiodic responses persisted, MSG-induced arcuate nucleus ablations prevented the photoperiod-dependent torpor observed in saline-treated Siberian hamsters. MSG-treated hamsters tended to possess greater fat reserves. To determine whether reductions in body fat would increase frequency of photoperiod-induced torpor after MSG treatment, hamsters underwent 2 wk of food restriction (70% of ad libitum) in experiment 2. Although food restriction did increase the frequency of torpor in both MSG- and saline-treated hamsters, it failed to normalize the proportion of MSG-treated hamsters undergoing photoperiod-dependent torpor. In experiment 3, postnatal MSG treatments reduced the proportion of hamsters entering 2DG-induced torpor-like hypothermia by ∼50% compared with saline-treated hamsters (38 vs. 72%). In those MSG-treated hamsters that did become hypothermic, their minimum temperature during hypothermia was significantly greater than comparable saline-treated hamsters. We conclude that 1) arcuate nucleus mechanisms mediate photoperiod-induced torpor, 2) food-restriction-induced torpor may also be reduced by MSG treatments, and 3) arcuate nucleus neurons make an important, albeit partial, contribution to 2DG-induced torpor-like hypothermia.
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Brito MN, Brito NA, Baro DJ, Song CK, Bartness TJ. Differential activation of the sympathetic innervation of adipose tissues by melanocortin receptor stimulation. Endocrinology 2007; 148:5339-47. [PMID: 17702843 DOI: 10.1210/en.2007-0621] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Melanocortins are implicated in the control of energy intake/expenditure. Centrally administered melanotan II (MTII), a synthetic melanocortin 3/4-receptor agonist, decreases adiposity beyond that accountable by food intake decreases. Melanocortin-4 receptor (MC4-R) mRNA is expressed on sympathetic nervous system (SNS) outflow neurons to white adipose tissue (WAT) in Siberian hamsters, suggesting a role in lipid mobilization. Therefore, we tested whether third ventricular injections of MTII increased sympathetic drive to WAT and interscapular brown adipose tissue (IBAT) using norepinephrine turnover (NETO) as a measure of sympathetic drive. We also tested for MTII-induced changes in lipolysis-related WAT gene expression (beta3-adrenoceptors, hormone sensitive lipase) and IBAT thermogenesis (beta3-adrenoceptor, uncoupling protein-1). Finally, we tested whether third ventricularly injected MTII, a highly selective MC4-R agonist (cyclo[beta-Ala-His-D-Phe-Arg-Trp-Glu]NH2) increased or agouti-related protein decreased IBAT temperature in hamsters implanted with sc IBAT temperature transponders. Centrally administered MTII provoked differential sympathetic drives to WAT and IBAT (increased inguinal WAT, dorsosubcutaneous WAT and IBAT NETO, but not epididymal WAT and retroperitoneal WAT NETO). MTII also increased circulating concentrations of the lipolytic products free fatty acids and glycerol but not plasma catecholamines, suggesting lipid mobilization via WAT SNS innervation and not via adrenal medullary catecholamines. WAT or IBAT gene expression was largely unaffected by acute MTII treatment, but IBAT temperature was increased by MTII and the MC4-R agonist and decreased by agouti-related protein. Collectively, this is the first demonstration of central melanocortin agonist stimulation of WAT lipolysis through the SNS and confirms melanocortin-induced changes in BAT thermogenesis.
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Affiliation(s)
- Márcia N Brito
- Department of Morphophysiological Sciences, State University of Maringá, Maringá, Brazil
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Fan W, Morrison SF, Cao WH, Yu P. Thermogenesis activated by central melanocortin signaling is dependent on neurons in the rostral raphe pallidus (rRPa) area. Brain Res 2007; 1179:61-9. [DOI: 10.1016/j.brainres.2007.04.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 03/23/2007] [Accepted: 04/04/2007] [Indexed: 11/16/2022]
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Tachibana T, Oikawa D, Adachi N, Boswell T, Furuse M. Central administration of alpha-melanocyte-stimulating hormone changes lipid metabolism in chicks. Comp Biochem Physiol A Mol Integr Physiol 2007; 148:408-12. [PMID: 17600745 DOI: 10.1016/j.cbpa.2007.05.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2006] [Revised: 05/31/2007] [Accepted: 05/31/2007] [Indexed: 11/27/2022]
Abstract
Alpha-melanocyte-stimulating hormone (MSH) is well known as an anorexigenic peptide in the brain of mammals. In addition to this, brain alpha-MSH enhances heat production (HP), indicating that the peptide acts as a catabolic factor in the regulation of energy metabolism. The anorexigenic effect of alpha-MSH is also observed in chicks (Gallus gallus), but no information has been available for its effect on HP. The present study was performed to examine whether intracerebroventricular (ICV) injection of alpha-MSH increases HP in chicks. The injection of alpha-MSH (10 and 100 pmol) did not affect oxygen consumption, carbon dioxide production and HP during the 1 h post-injection period. This result was supported by another result that ICV injection of alpha-MSH did not affect locomotion activity in chicks. In contrast, the respiratory quotient was significantly lowered by the ICV injection of MSH. We also found that alpha-MSH significantly increased plasma non-esterified fatty acid concentrations. In summary, brain alpha-MSH appears to exert generally catabolic effects on lipid metabolism in the chick, but does not appear to be involved in the regulation of HP.
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Affiliation(s)
- Tetsuya Tachibana
- Laboratory of Advanced Animal and Marine Bioresources, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka 812-8581, Japan.
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Voss-Andreae A, Murphy JG, Ellacott KLJ, Stuart RC, Nillni EA, Cone RD, Fan W. Role of the central melanocortin circuitry in adaptive thermogenesis of brown adipose tissue. Endocrinology 2007; 148:1550-60. [PMID: 17194736 DOI: 10.1210/en.2006-1389] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The central melanocortin 4 receptor (MC4R) plays a critical role in energy homeostasis, although little is known regarding its role in the regulation of adaptive thermogenesis of brown adipose tissue (BAT). Here we show using retrograde transsynaptic tracing with attenuated pseudorabies virus coupled with dual-label immunohistochemistry that specific subsets of MC4R-expressing neurons in multiple nuclei of the central nervous system known to regulate sympathetic outflow polysynaptically connect with interscapular BAT (IBAT). Furthermore, we show that MC4R-/- and agouti-related peptide-treated mice are defective in HF diet-induced up-regulation of uncoupling protein 1 in IBAT. Additionally, MC4R-/- mice exposed to 4 C for 4 h exhibit a defect in up-regulation of uncoupling protein 1 levels in IBAT. Our results provide a neuroanatomic substrate for MC4R regulating sympathetically mediated IBAT thermogenesis and demonstrate that the MC4R is critically required for acute high-fat- and cold-induced IBAT thermogenesis.
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MESH Headings
- Acclimatization/physiology
- Adipose Tissue, Brown/drug effects
- Adipose Tissue, Brown/metabolism
- Adipose Tissue, Brown/physiology
- Agouti-Related Protein
- Animals
- Central Nervous System/chemistry
- Cold Temperature
- Diet, Atherogenic
- Herpesvirus 1, Suid
- Intercellular Signaling Peptides and Proteins/pharmacology
- Ion Channels/metabolism
- Male
- Melanocortins/metabolism
- Melanocortins/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mitochondrial Proteins/metabolism
- Models, Biological
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Receptor, Melanocortin, Type 4/physiology
- Thermogenesis/physiology
- Uncoupling Protein 1
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Affiliation(s)
- Adriana Voss-Andreae
- Center for the Study of Weight Regulation and Associated Disorders and Vollum Institute, Oregon Health and Sciences University, Portland, Oregon 97239-3098, and Division of Endocrinology, Rhode Island Hospital, Providence 02903, USA
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