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Gan HW, Cerbone M, Dattani MT. Appetite- and Weight-Regulating Neuroendocrine Circuitry in Hypothalamic Obesity. Endocr Rev 2024; 45:309-342. [PMID: 38019584 PMCID: PMC11074800 DOI: 10.1210/endrev/bnad033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 10/25/2023] [Accepted: 11/27/2023] [Indexed: 11/30/2023]
Abstract
Since hypothalamic obesity (HyOb) was first described over 120 years ago by Joseph Babinski and Alfred Fröhlich, advances in molecular genetic laboratory techniques have allowed us to elucidate various components of the intricate neurocircuitry governing appetite and weight regulation connecting the hypothalamus, pituitary gland, brainstem, adipose tissue, pancreas, and gastrointestinal tract. On a background of an increasing prevalence of population-level common obesity, the number of survivors of congenital (eg, septo-optic dysplasia, Prader-Willi syndrome) and acquired (eg, central nervous system tumors) hypothalamic disorders is increasing, thanks to earlier diagnosis and management as well as better oncological therapies. Although to date the discovery of several appetite-regulating peptides has led to the development of a range of targeted molecular therapies for monogenic obesity syndromes, outside of these disorders these discoveries have not translated into the development of efficacious treatments for other forms of HyOb. This review aims to summarize our current understanding of the neuroendocrine physiology of appetite and weight regulation, and explore our current understanding of the pathophysiology of HyOb.
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Affiliation(s)
- Hoong-Wei Gan
- Department of Endocrinology, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London WC1N 3JH, UK
- Genetics & Genomic Medicine Research & Teaching Department, University College London Great Ormond Street Institute for Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Manuela Cerbone
- Department of Endocrinology, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London WC1N 3JH, UK
- Genetics & Genomic Medicine Research & Teaching Department, University College London Great Ormond Street Institute for Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Mehul Tulsidas Dattani
- Department of Endocrinology, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London WC1N 3JH, UK
- Genetics & Genomic Medicine Research & Teaching Department, University College London Great Ormond Street Institute for Child Health, 30 Guilford Street, London WC1N 1EH, UK
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2
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Guan D, Men Y, Bartlett A, Hernández MAS, Xu J, Yi X, Li HS, Kong D, Mazitschek R, Ozcan U. Central inhibition of HDAC6 re-sensitizes leptin signaling during obesity to induce profound weight loss. Cell Metab 2024; 36:857-876.e10. [PMID: 38569472 DOI: 10.1016/j.cmet.2024.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 11/02/2023] [Accepted: 02/13/2024] [Indexed: 04/05/2024]
Abstract
Leptin resistance during excess weight gain significantly contributes to the recidivism of obesity to leptin-based pharmacological therapies. The mechanisms underlying the inhibition of leptin receptor (LepR) signaling during obesity are still elusive. Here, we report that histone deacetylase 6 (HDAC6) interacts with LepR, reducing the latter's activity, and that pharmacological inhibition of HDAC6 activity disrupts this interaction and augments leptin signaling. Treatment of diet-induced obese mice with blood-brain barrier (BBB)-permeable HDAC6 inhibitors profoundly reduces food intake and leads to potent weight loss without affecting the muscle mass. Genetic depletion of Hdac6 in Agouti-related protein (AgRP)-expressing neurons or administration with BBB-impermeable HDAC6 inhibitors results in a lack of such anti-obesity effect. Together, these findings represent the first report describing a mechanistically validated and pharmaceutically tractable therapeutic approach to directly increase LepR activity as well as identifying centrally but not peripherally acting HDAC6 inhibitors as potent leptin sensitizers and anti-obesity agents.
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Affiliation(s)
- Dongxian Guan
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Yuqin Men
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Alexander Bartlett
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Jie Xu
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Xinchi Yi
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Hu-Song Li
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Dong Kong
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ralph Mazitschek
- Massachusetts General Hospital, Center for Systems Biology, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Umut Ozcan
- Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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3
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Sweeney P, Gimenez LE, Hernandez CC, Cone RD. Targeting the central melanocortin system for the treatment of metabolic disorders. Nat Rev Endocrinol 2023; 19:507-519. [PMID: 37365323 DOI: 10.1038/s41574-023-00855-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/18/2023] [Indexed: 06/28/2023]
Abstract
A large body of preclinical and clinical data shows that the central melanocortin system is a promising therapeutic target for treating various metabolic disorders such as obesity and cachexia, as well as anorexia nervosa. Setmelanotide, which functions by engaging the central melanocortin circuitry, was approved by the FDA in 2020 for use in certain forms of syndromic obesity. Furthermore, the FDA approvals in 2019 of two peptide drugs targeting melanocortin receptors for the treatment of generalized hypoactive sexual desire disorder (bremelanotide) and erythropoietic protoporphyria-associated phototoxicity (afamelanotide) demonstrate the safety of this class of peptides. These approvals have also renewed excitement in the development of therapeutics targeting the melanocortin system. Here, we review the anatomy and function of the melanocortin system, discuss progress and challenges in developing melanocortin receptor-based therapeutics, and outline potential metabolic and behavioural disorders that could be addressed using pharmacological agents targeting these receptors.
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Affiliation(s)
- Patrick Sweeney
- School of Molecular and Cellular Biology, College of Liberal Arts and Sciences, University of Illinois Urbana-Champaign, Champaign, IL, USA
| | - Luis E Gimenez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | | | - Roger D Cone
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
- Department of Molecular and Integrative Physiology, School of Medicine, University of Michigan, Ann Arbor, MI, USA.
- Department of Molecular, Cellular, and Developmental Biology, College of Literature Science and the Arts, University of Michigan, Ann Arbor, MI, USA.
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4
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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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Ahmed RM, Halliday G, Hodges JR. Hypothalamic symptoms of frontotemporal dementia disorders. HANDBOOK OF CLINICAL NEUROLOGY 2021; 182:269-280. [PMID: 34266598 DOI: 10.1016/b978-0-12-819973-2.00019-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Frontotemporal dementia (FTD) has traditionally been regarded as a disease of cognition and behavior, but emerging evidence suggests that the disease also affects body functions including changes in eating behavior and metabolism, autonomic function, sleep behavior, and sexual function. Central to these changes are potentially complex neural networks involving the hypothalamus, with hypothalamic atrophy shown in behavioral variant FTD. The physiological changes found in FTD are reviewed and the key neural networks and neuroendocrine changes mediating these changes in function discussed, including the ability to use these changes as biomarkers to aid in disease diagnosis, monitoring disease progression, and as potential treatment targets.
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Affiliation(s)
- Rebekah M Ahmed
- Memory and Cognition Clinic, Department of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, NSW, Australia; Central Sydney Medical School and Brain & Mind Centre, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia.
| | - Glenda Halliday
- Central Sydney Medical School and Brain & Mind Centre, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - John R Hodges
- Central Sydney Medical School and Brain & Mind Centre, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
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Loganathan N, McIlwraith EK, Belsham DD. Bisphenol A Induces Agrp Gene Expression in Hypothalamic Neurons through a Mechanism Involving ATF3. Neuroendocrinology 2021; 111:678-695. [PMID: 32575098 DOI: 10.1159/000509592] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 06/22/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND Bisphenol A (BPA) is a ubiquitous endocrine disrupting chemical and obesogen. Although limited evidence exists of the effects of BPA on hypothalamic agouti-related peptide (AgRP) levels, the mechanisms underlying these effects remain unknown. Given that AgRP is a potent orexigenic neuropeptide, determining the mechanism by which BPA increases AgRP is critical to preventing the progression to metabolic disease. METHODS Using quantitative reverse transcriptase polymerase chain reaction, we investigated the response of Agrp-expressing mouse hypothalamic cell lines to BPA treatment. The percentage of total BPA entering hypothalamic cells in culture was quantified using an enzyme-linked immunosorbent assay. In order to identify the mechanism underlying BPA-mediated changes in Agrp, siRNA knockdown of transcription factors, FOXO1, CHOP, ATF3, ATF4, ATF6, and small-molecule inhibitors of endoplasmic reticulum stress, JNK or MEK/ERK were used. RESULTS BPA increased mRNA levels of Agrp in six hypothalamic cell lines (mHypoA-59, mHypoE-41, mHypoA-2/12, mHypoE-46, mHypoE-44, and mHypoE-42). Interestingly, only 18% of the total BPA in the culture medium entered the cells after 24 h, suggesting that the exposure concentration is much lower than the treatment concentration. BPA increased pre-Agrp mRNA levels, indicating increased Agrp transcription. Knockdown of the transcription factor ATF3 prevented BPA-mediated increase in Agrp, pre-Agrp, and in part Npy mRNA levels. However, chemical chaperone, sodium phenylbutyrate, JNK inhibitor, SP600125, or the MEK/ERK inhibitor PD0352901 did not block BPA-induced Agrp upregulation. CONCLUSION Overall, these results indicate that hypothalamic Agrp is susceptible to dysregulation by BPA and implicate ATF3 as a common mediator of the orexigenic effects of BPA in hypothalamic neurons.
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Affiliation(s)
- Neruja Loganathan
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Emma K McIlwraith
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Denise D Belsham
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada,
- Department of Obstetrics and Gynaecology, University of Toronto, Toronto, Ontario, Canada,
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada,
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Huang D, Zhang B, Han T, Liu G, Chen X, Zhao Z, Feng J, Yang J, Wang T. Genome-wide prediction and comparative transcriptomic analysis reveals the G protein-coupled receptors involved in gonadal development of Apostichopus japonicus. Genomics 2020; 113:967-978. [PMID: 33144216 DOI: 10.1016/j.ygeno.2020.10.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/26/2020] [Accepted: 10/28/2020] [Indexed: 01/14/2023]
Abstract
The sea cucumber Apostichopus japonicus is dioecious, with seasonal reproduction. G protein-coupled receptor (GPCR)-mediated signaling systems might play critical roles in the reproductive control of A. japonicus. Here, we classified GPCR from the genome in silico and used transcriptomic analyses to further mine those that function in gonadal-development control. Totally, 487 GPCRs were predicted from A. japonicus, and 183 of these were further annotated to molecular pathways. Transcriptome analysis revealed 327 GPCRs expressed in gonads, and these were classified into four families and 19 subfamilies. Three pathways were apparently associated with reproduction, including neuroactive ligand-receptor interaction, the mTOR and Wnt signaling pathways. Seven and eight ovary- and testis-specific GPCRs were filtered, and the gene expression profiles were determined in multiple tissues and gonads at different developmental stages by qPCR. These results provide new insights into the discovery of GPCR-mediated signaling control in sea cucumber reproduction, especially in gonadal development control.
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Affiliation(s)
- Dexiang Huang
- National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization, Marine Science and Technology College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China
| | - Bing Zhang
- National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization, Marine Science and Technology College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China
| | - Tao Han
- Department of Aquaculture, Zhejiang Ocean University, 316022, Zhoushan, Zhejiang, People's Republic of China
| | - Guangbin Liu
- Marine Biology Institute of Shandong Province, 266104 Qingdao, Shandong, People's Republic of China
| | - Xu Chen
- National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization, Marine Science and Technology College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China
| | - Zihao Zhao
- National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization, Marine Science and Technology College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China
| | - Jiaqian Feng
- National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization, Marine Science and Technology College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China
| | - Jingwen Yang
- National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization, Marine Science and Technology College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China; National Engineering Research Center of Marine Facilities Aquaculture, Marine Science and Technology College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China.
| | - Tianming Wang
- National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization, Marine Science and Technology College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China; National Engineering Research Center of Marine Facilities Aquaculture, Marine Science and Technology College, Zhejiang Ocean University, Zhoushan, Zhejiang 316022, People's Republic of China.
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8
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Romano A, Friuli M, Cifani C, Gaetani S. Oxytocin in the neural control of eating: At the crossroad between homeostatic and non-homeostatic signals. Neuropharmacology 2020; 171:108082. [PMID: 32259527 DOI: 10.1016/j.neuropharm.2020.108082] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 03/10/2020] [Accepted: 03/30/2020] [Indexed: 12/21/2022]
Abstract
The understanding of the biological substrates regulating feeding behavior is relevant to address the health problems related to food overconsumption. Several studies have expanded the conventional view of the homeostatic regulation of body weight mainly orchestrated by the hypothalamus, to include also the non-homeostatic control of appetite. Such processes include food reward and are mainly coordinated by the activation of the central mesolimbic dopaminergic pathway. The identification of endogenous systems acting as a bridge between homoeostatic and non-homeostatic pathways might represent a significant step toward the development of drugs for the treatment of aberrant eating patterns. Oxytocin is a hypothalamic hormone that is directly secreted into the brain and reaches the blood circulation through the neurohypophysis. Oxytocin regulates a variety of physiologic functions, including eating and metabolism. In the last years both preclinical and clinical studies well characterized oxytocin for its effects in reducing food intake and body weight. In the present review we summarize the role played by oxytocin in the control of both homeostatic and non-homeostatic eating, within cognitive, metabolic and reward mechanisms, to mostly highlight its potential therapeutic effects as a new pharmacological approach for the development of drugs for eating disorders. We conclude that the central oxytocinergic system is possibly one of the mechanisms that coordinate energy balance at the crossroads between homeostatic and non-homeostatic mechanisms. This concept should foster studies aimed at exploring the possible exploitation of oxytocin in the treatment of aberrant eating patterns. This article is part of the special issue on Neuropeptides.
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Affiliation(s)
- Adele Romano
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Marzia Friuli
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Carlo Cifani
- School of Pharmacy, Pharmacology Unit, University of Camerino, via Madonna delle Carceri, 9, 62032, Camerino, MC, Italy
| | - Silvana Gaetani
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy.
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Pituitary Adenylate Cyclase-Activating Polypeptide in the Ventromedial Hypothalamus Is Responsible for Food Intake Behavior by Modulating the Expression of Agouti-Related Peptide in Mice. Mol Neurobiol 2020; 57:2101-2114. [DOI: 10.1007/s12035-019-01864-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 12/22/2019] [Indexed: 12/18/2022]
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10
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Koerperich ZM, Ericson MD, Freeman KT, Speth RC, Pogozheva ID, Mosberg HI, Haskell-Luevano C. Incorporation of Agouti-Related Protein (AgRP) Human Single Nucleotide Polymorphisms (SNPs) in the AgRP-Derived Macrocyclic Scaffold c[Pro-Arg-Phe-Phe-Asn-Ala-Phe-dPro] Decreases Melanocortin-4 Receptor Antagonist Potency and Results in the Discovery of Melanocortin-5 Receptor Antagonists. J Med Chem 2020; 63:2194-2208. [PMID: 31845801 DOI: 10.1021/acs.jmedchem.9b00860] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
While the melanocortin receptors (MCRs) are known to be involved in numerous biological pathways, the potential roles of the MC5R have not been clearly elucidated in humans. Agouti-related protein (AgRP), an MC3R/MC4R antagonist and MC4R inverse agonist, contains an exposed β-hairpin loop composed of six residues (Arg-Phe-Phe-Asn-Ala-Phe) that is imperative for binding and function. Within this active loop of AgRP, four human missense polymorphisms were deposited into the NIH Variation Viewer database. These polymorphisms, Arg111Cys, Arg111His, Phe112Tyr, and Ala115Val (AgRP full-length numbering), were incorporated into the peptide macrocycles c[Pro1-Arg2-Phe3-Phe4-Xaa5-Ala6-Phe7-dPro8], where Xaa was Dap5 or Asn5, to explore the functional effects of these naturally occurring substitutions in a simplified AgRP scaffold. All peptides lowered potency at least 10-fold in a cAMP accumulation assay compared to the parent sequences at the MC4Rs. Compounds MDE 6-82-3c, ZMK 2-82, MDE 6-82-1c, ZMK 2-85, and ZMK 2-112 are also the first AgRP-based chemotypes that antagonize the MC5R.
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Affiliation(s)
- Zoe M Koerperich
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Mark D Ericson
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Katie T Freeman
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Robert C Speth
- College of Pharmacy, Nova Southeastern University, Fort Lauderdale, Florida 33328-2018, United States.,College of Medicine, Georgetown University, Washington, D.C. 20057, United States
| | - Irina D Pogozheva
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Henry I Mosberg
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
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11
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Lucka A, Wysokiński A. Association between adiposity and fasting serum levels of appetite-regulating peptides: Leptin, neuropeptide Y, desacyl ghrelin, peptide YY(1-36), obestatin, cocaine and amphetamine-regulated transcript, and agouti-related protein in nonobese participants. CHINESE J PHYSIOL 2019; 62:217-225. [PMID: 31670286 DOI: 10.4103/cjp.cjp_29_19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The objective of this study was to evaluate the association between adiposity parameters and fasting serum levels of appetite-regulating peptides: leptin, neuropeptide Y (NPY), desacyl ghrelin, peptide YY(1-36), obestatin, cocaine- and amphetamine-regulated transcript (CART), and agouti-related protein in 30 healthy, non-obese subjects. Thirty European Caucasian adult participants were included in the study (17 men and 13 women). Body composition (body fat and lean body mass) was determined using bioelectrical impedance analysis. Concentrations of peptides in serum were assessed using the enzyme-linked immunosorbent assay. Women had higher level of leptin (P < 0.001), with no other differences for analyzed peptides. We have found a significant correlation between serum concentrations of CART and NPY (P < 0.001). Fasting leptin level was associated with age (P = 0.002), waist circumference (P < 0.001), and lean body mass (P < 0.001). Levels of ghrelin were lower in participants with dyslipidemia (P = 0.009). Levels of obestatin (P = 0.008) and leptin (P = 0.02) were higher in participants with insulin resistance. Associations between body fat and appetite-regulating peptides are more complex than simple feedback loops. Leptin is probably the first signal in the pathway that regulates body fat content, as of all analyzed peptides leptin was the only one that was associated with body composition or anthropometric measurements.
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Affiliation(s)
- Anna Lucka
- Department of Old Age Psychiatry and Psychotic Disorders, Medical University of Lodz, Łódź, Poland
| | - Adam Wysokiński
- Department of Old Age Psychiatry and Psychotic Disorders, Medical University of Lodz, Łódź, Poland
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12
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Chen Y, Essner RA, Kosar S, Miller OH, Lin YC, Mesgarzadeh S, Knight ZA. Sustained NPY signaling enables AgRP neurons to drive feeding. eLife 2019; 8:e46348. [PMID: 31033437 PMCID: PMC6513552 DOI: 10.7554/elife.46348] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/26/2019] [Indexed: 12/20/2022] Open
Abstract
Artificial stimulation of Agouti-Related Peptide (AgRP) neurons promotes intense food consumption, yet paradoxically during natural behavior these cells are inhibited before feeding begins. Previously, to reconcile these observations, we showed that brief stimulation of AgRP neurons can generate hunger that persists for tens of minutes, but the mechanisms underlying this sustained hunger drive remain unknown (Chen et al., 2016). Here we show that Neuropeptide Y (NPY) is uniquely required for the long-lasting effects of AgRP neurons on feeding behavior. We blocked the ability of AgRP neurons to signal through AgRP, NPY, or GABA, and then stimulated these cells using a paradigm that mimics their natural regulation. Deletion of NPY, but not AgRP or GABA, abolished optically-stimulated feeding, and this was rescued by NPY re-expression selectively in AgRP neurons. These findings reveal a unique role for NPY in sustaining hunger in the interval between food discovery and consumption.
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Affiliation(s)
- Yiming Chen
- Kavli Institute for Fundamental NeuroscienceUniversity of California, San FranciscoSan FranciscoUnited States
- Neuroscience Graduate ProgramUniversity of California, San FranciscoSan FranciscoUnited States
| | - Rachel A Essner
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
| | - Seher Kosar
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
| | - Oliver H Miller
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
| | - Yen-Chu Lin
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
| | - Sheyda Mesgarzadeh
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
| | - Zachary A Knight
- Kavli Institute for Fundamental NeuroscienceUniversity of California, San FranciscoSan FranciscoUnited States
- Neuroscience Graduate ProgramUniversity of California, San FranciscoSan FranciscoUnited States
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteUniversity of California, San FranciscoSan FranciscoUnited States
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13
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Abstract
This review evaluates published studies regarding alpha-melanocyte stimulating hormone (α-MSH) in ghrelin-elicited feeding and gut motility. We have sought to integrate all available evidences to provide a complete review on the properties of melanocortin receptors (MCR) and the potential clinical treatment of α-MSH after ghrelin-elicited feeding and gut motility. The available studies were grouped into four categories: food intake, gastric emptying, small intestinal transit, and colonic transit. As we describe, the literature provides evidence of the ability of ghrelin to increase food intake, gastric emptying, small intestinal transit, and colonic transit. α-MSH, which displays high affinity for the MC3 and MC4 receptors, can competitively activate MCRs with agouti-related protein stimulated by ghrelin, and partly attenuates the effect of acyl ghrelin on food intake. Central ghrelin-induced acceleration of gastric emptying is not mediated by MCRs, but the acceleration of the small intestinal transit is at least partly mediated via MCRs in the brain. Similar to fecal pellets and total fecal weight, distal colonic motility and secretion are partly mediated by MCRs in the brain. The interplay between acyl ghrelin and MCRs may provide a new therapeutic avenue to ameliorate anorexia and constipation.
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Affiliation(s)
- Hsien-Hao Huang
- Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Institute of Emergency and Critical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC
| | - Chih-Yen Chen
- Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC
- Taiwan Association for the Study of Small Intestinal Diseases, Guishan, Taiwan, ROC
- Chinese Taipei Society for the Study of Obesity, Taipei, Taiwan, ROC
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14
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Girardet C, Marks DL, Butler AA. Melanocortin-3 Receptors Expressed on Agouti-Related Peptide Neurons Inhibit Feeding Behavior in Female Mice. Obesity (Silver Spring) 2018; 26:1849-1855. [PMID: 30426710 PMCID: PMC7294842 DOI: 10.1002/oby.22306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/27/2018] [Accepted: 07/30/2018] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Activation of hypothalamic agouti-related peptide expressing (AgRP)+ve neurons during energy deficit is a negative valence signal, rapidly activating food-seeking behaviors. This study examined the roles of melanocortin-3 receptors (MC3Rs) coexpressed in a subpopulation of AgRP+ve neurons. METHODS AgRP-MC3R mice expressing MC3Rs selectively in AgRP+ve neurons were generated by crossing AgRP-IRES-Cre mice with LoxTBMc3r mice containing a "loxP-STOP-loxP" sequence in the 5' untranslated region. Body weight, body composition, and feeding behavior were assessed during ad libitum and time-restricted feeding conditions. RESULTS In females, food intake of AgRP-IRES-Cre+ve (n = 7) or AgRP-IRES-Cre-ve (n = 9) mice was not significantly different; these mice were therefore pooled to form the "control" group. Female AgRP-MC3R mice exhibited lower food intake (25.4 ± 2.4 kJ/12 h; n = 6) compared with controls (35.3 ± 1.8 kJ/12 h; n = 16) and LoxTBMc3r mice (32.1 ± 2.1 kJ/12 h; n = 9) in the active phase during the dark period. Food intake during the rest phase (lights on) when mice consume less food (9-10 kJ) was normal between genotypes. Body weight and composition of AgRP-MC3R and LoxTBMc3r mice were similar, suggesting compensatory mechanisms for reduced calorie intake. Remarkably, AgRP-MC3R mice continued to consume less food during refeeding after fasting and time-restricted feeding. CONCLUSIONS MC3Rs expressed on AgRP+ve neurons appear to exert a strong inhibitory signal on hypothalamic networks governing feeding behavior.
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Affiliation(s)
- Clemence Girardet
- Department of Pharmacology & Physiology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Daniel L. Marks
- Department of Pediatrics, Papé Family Pediatric Research Institute, Oregon Health & Science University, Mail Code L481 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA
| | - Andrew A. Butler
- Department of Pharmacology & Physiology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
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15
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Suyama S, Yada T. New insight into GABAergic neurons in the hypothalamic feeding regulation. J Physiol Sci 2018; 68:717-722. [PMID: 30003408 PMCID: PMC10717766 DOI: 10.1007/s12576-018-0622-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 05/30/2018] [Indexed: 12/11/2022]
Abstract
Several lines of study have suggested that GABA in the hypothalamic feeding center plays a role in promoting food intake. Recent studies revealed that not only NPY/AgRP neurons in the hypothalamic arcuate nucleus (ARC) that co-express GABA but also other GABAergic neurons act as an orexigenic. Here, we review the progress of studies on hypothalamic GABAergic neurons distributed in ARC, dorsomedial hypothalamus (DMH), and lateral hypothalamus (LH). Three advanced technologies have been applied and greatly contributed to the recent progress. Optogenetic (and chemogenetic) approaches map input and output pathways of particular subpopulations of GABAergic neurons. In vivo Ca2+ imaging using GRIN lens and GCaMP can correlate the activity of GABAergic neuron subpopulations with feeding behavior. Single-cell RNA-seq approach clarifies precise transcriptional profiles of GABAergic neuron subpopulations. These approaches have shown diversity of GABAergic neurons and the subpopulation-dependent role in feeding regulation.
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Affiliation(s)
- Shigetomo Suyama
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi, 320-0498, Japan.
| | - Toshihiko Yada
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke, Tochigi, 320-0498, Japan.
- Kansai Electric Power Medical Research Institute, 1-5-6 Minatojimaminamimachi, Chuou-ku, Kobe, 650-0047, Japan.
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16
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Ericson MD, Haskell-Luevano C. A Review of Single-Nucleotide Polymorphisms in Orexigenic Neuropeptides Targeting G Protein-Coupled Receptors. ACS Chem Neurosci 2018; 9:1235-1246. [PMID: 29714060 DOI: 10.1021/acschemneuro.8b00151] [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: 12/12/2022] Open
Abstract
Many physiological pathways are involved in appetite, food intake, and the maintenance of energy homeostasis. In particular, neuropeptides within the central nervous system have been demonstrated to be critical signaling molecules for modulating appetite. Both anorexigenic (appetite-decreasing) and orexigenic (appetite-stimulating) neuropeptides have been described. The biological effects of these neuropeptides can be observed following central administration in animal models. This review focuses on single nucleotide polymorphisms (SNPs) in six orexigenic neuropeptides: agouti-related protein (AGRP), galanin, melanin concentrating hormone (MCH), neuropeptide Y (NPY), orexin A, and orexin B. Following a brief summary of the neuropeptides and their orexigenic activities, reports associating SNPs within the orexigenic neuropeptides to energy homeostasis, food intake, obesity, and BMI in humans are reviewed. Additionally, the NIH tool Variation Viewer was utilized to identify missense SNPs within the mature, biologically active neuropeptide sequences. For SNPs found through Variation Viewer, a concise discussion on relevant pharmacological structure-activity relationship studies for select SNPs is included. This review is meant to update reported orexigenic neuropeptide SNPs and demonstrate the potential utility of genomic sequence databases for finding SNPs that may result in altered receptor signaling for neuropeptide pathways associated with appetite.
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Affiliation(s)
- Mark D. Ericson
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
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17
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Hasek LY, Phillips RJ, Zhang G, Kinzig KP, Kim CY, Powley TL, Hamaker BR. Dietary Slowly Digestible Starch Triggers the Gut-Brain Axis in Obese Rats with Accompanied Reduced Food Intake. Mol Nutr Food Res 2018; 62. [PMID: 29230947 DOI: 10.1002/mnfr.201700117] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 10/19/2017] [Indexed: 01/10/2023]
Abstract
SCOPE Slowly digestible starch (SDS), as a functional carbohydrate providing a slow and sustained glucose release, may be able to modulate food intake through activation of the gut-brain axis. METHODS AND RESULTS Diet-induced obese rats were used to test the effect on feeding behavior of high-fat (HF) diets containing an SDS, fabricated to digest into the ileum, as compared to rapidly digestible starch (RDS). Ingestion of the HF-SDS diet over an 11-week period reduced daily food intake, through smaller meal size, to the same level as a lean body control group, while the group consuming the HF-RDS diet remained at a high food intake. Expression levels (mRNA) of the hypothalamic orexigenic neuropeptide Y (NPY) and Agouti-related peptide (AgRP) were significantly reduced, and the anorexigenic corticotropin-releasing hormone (CRH) was increased, in the HF-SDS fed group compared to the HF-RDS group, and to the level of the lean control group. CONCLUSION SDS with digestion into the ileum reduced daily food intake and paralleled suppressed expression of appetite-stimulating neuropeptide genes associated with the gut-brain axis. This novel finding suggests further exploration involving a clinical study and potential development of SDS-based functional foods as an approach to obesity control.
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Affiliation(s)
- Like Y Hasek
- Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West Lafayette, IN, USA
| | - Robert J Phillips
- Department of Psychological Science, Purdue University, West Lafayette, IN, USA
| | - Genyi Zhang
- School of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Kimberly P Kinzig
- Department of Psychological Science, Purdue University, West Lafayette, IN, USA
| | - Choon Young Kim
- Department of Food and Nutrition, Yeungnam University, Gyeongsan, Gyeongbuk, Republic of Korea
| | - Terry L Powley
- Department of Psychological Science, Purdue University, West Lafayette, IN, USA
| | - Bruce R Hamaker
- Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West Lafayette, IN, USA
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18
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Adank DN, Lunzer MM, Lensing CJ, Wilber SL, Gancarz AM, Haskell-Luevano C. Comparative in Vivo Investigation of Intrathecal and Intracerebroventricular Administration with Melanocortin Ligands MTII and AGRP into Mice. ACS Chem Neurosci 2018; 9:320-327. [PMID: 28968061 PMCID: PMC5821609 DOI: 10.1021/acschemneuro.7b00330] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Central administration of melanocortin ligands has been used as a critical technique to study energy homeostasis. While intracerebroventricular (ICV) injection is the most commonly used method during these investigations, intrathecal (IT) injection can be equally efficacious for the central delivery of ligands. Importantly, intrathecal administration can optimize exploration of melanocortin receptors in the spinal cord. Herein, we investigate comparative IT and ICV administration of two melanocortin ligands, the synthetic MTII (Ac-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-NH2) MC4R agonist and agouti-related peptide [AGRP(87-132)] MC4R inverse agonist/antagonist, on the same batch of age-matched mice in TSE metabolic cages undergoing a nocturnal satiated paradigm. To our knowledge, this is the first study to test how central administration of these ligands directly to the spinal cord affects energy homeostasis. Results showed, as expected, that MTII IT administration caused a decrease in food and water intake and an overall negative energy balance without affecting activity. As anticipated, IT administration of AGRP caused weight gain, increase of food/water intake, and increase respiratory exchange ratio (RER). Unexpectantly, the prolonged activity of AGRP was notably shorter (2 days) compared to mice given ICV injections of the same concentrations in previous studies (7 days or more).1-4 It appears that IT administration results in a more sensitive response that may be a good approach for testing synthetic compound potency values ranging in nanomolar to high micromolar in vitro EC50 values. Indeed, our investigation reveals that the spine influences a different melanocortin response compared to the brain for the AGRP ligand. This study indicates that IT administration can be a useful technique for future metabolic studies using melanocortin ligands and highlights the importance of exploring the role of melanocortin receptors in the spinal cord.
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MESH Headings
- Agouti-Related Protein/administration & dosage
- Animals
- Body Weight/drug effects
- Catheters, Indwelling
- Cross-Over Studies
- Eating/drug effects
- Homeostasis/drug effects
- Injections, Intraventricular
- Injections, Spinal
- Male
- Mice, 129 Strain
- Mice, Inbred C57BL
- Peptide Fragments/administration & dosage
- Receptor, Melanocortin, Type 4/agonists
- Receptor, Melanocortin, Type 4/antagonists & inhibitors
- Receptor, Melanocortin, Type 4/metabolism
- Time Factors
- alpha-MSH/administration & dosage
- alpha-MSH/analogs & derivatives
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Affiliation(s)
- Danielle N. Adank
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
| | - Mary M. Lunzer
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
| | - Cody J. Lensing
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
| | - Stacey L. Wilber
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
| | - Amy M. Gancarz
- Department of Psychology, California State University Bakersfield, Bakersfield, CA 93311, United States
| | - Carrie Haskell-Luevano
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
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19
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Gartner SN, Aidney F, Klockars A, Prosser C, Carpenter EA, Isgrove K, Levine AS, Olszewski PK. Intragastric preloads of l-tryptophan reduce ingestive behavior via oxytocinergic neural mechanisms in male mice. Appetite 2018; 125:278-286. [PMID: 29471071 DOI: 10.1016/j.appet.2018.02.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 02/09/2018] [Accepted: 02/15/2018] [Indexed: 11/29/2022]
Abstract
Human and laboratory animal studies suggest that dietary supplementation of a free essential amino acid, l-tryptophan (TRP), reduces food intake. It is unclear whether an acute gastric preload of TRP decreases consumption and whether central mechanisms underlie TRP-driven hypophagia. We examined the effect of TRP administered via intragastric gavage on energy- and palatability-induced feeding in mice. We sought to identify central mechanisms through which TRP suppresses appetite. Effects of TRP on consumption of energy-dense and energy-dilute tastants were established in mice stimulated to eat by energy deprivation or palatability. A conditioned taste aversion (CTA) paradigm was used to assess whether hypophagia is unrelated to sickness. c-Fos immunohistochemistry was employed to detect TRP-induced activation of feeding-related brain sites and of oxytocin (OT) neurons, a crucial component of satiety circuits. Also, expression of OT mRNA was assessed with real-time PCR. The functional importance of OT in mediating TRP-driven hypophagia was substantiated by showing the ability of OT receptor blockade to abolish TRP-induced decrease in feeding. TRP reduced intake of energy-dense standard chow in deprived animals and energy-dense palatable chow in sated mice. Anorexigenic doses of TRP did not cause a CTA. TRP failed to affect intake of palatable yet calorie-dilute or noncaloric solutions (10% sucrose, 4.1% Intralipid or 0.1% saccharin) even for TRP doses that decreased water intake in thirsty mice. Fos analysis revealed that TRP increases activation of several key feeding-related brain areas, especially in the brain stem and hypothalamus. TRP activated hypothalamic OT neurons and increased OT mRNA levels, whereas pretreatment with an OT antagonist abolished TRP-driven hypophagia. We conclude that intragastric TRP decreases food and water intake, and TRP-induced hypophagia is partially mediated via central circuits that encompass OT.
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Affiliation(s)
| | | | | | - Colin Prosser
- Dairy Goat Co-operative (NZ) Ltd, Hamilton, New Zealand
| | | | | | - Allen S Levine
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA
| | - Pawel K Olszewski
- University of Waikato, Hamilton, New Zealand; Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN, USA.
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20
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Subkhangulova A, Malik AR, Hermey G, Popp O, Dittmar G, Rathjen T, Poy MN, Stumpf A, Beed PS, Schmitz D, Breiderhoff T, Willnow TE. SORCS1 and SORCS3 control energy balance and orexigenic peptide production. EMBO Rep 2018; 19:embr.201744810. [PMID: 29440124 PMCID: PMC5891432 DOI: 10.15252/embr.201744810] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 01/15/2018] [Accepted: 01/22/2018] [Indexed: 12/20/2022] Open
Abstract
SORCS1 and SORCS3 are two related sorting receptors expressed in neurons of the arcuate nucleus of the hypothalamus. Using mouse models with individual or dual receptor deficiencies, we document a previously unknown function of these receptors in central control of metabolism. Specifically, SORCS1 and SORCS3 act as intracellular trafficking receptors for tropomyosin-related kinase B to attenuate signaling by brain-derived neurotrophic factor, a potent regulator of energy homeostasis. Loss of the joint action of SORCS1 and SORCS3 in mutant mice results in excessive production of the orexigenic neuropeptide agouti-related peptide and in a state of chronic energy excess characterized by enhanced food intake, decreased locomotor activity, diminished usage of lipids as metabolic fuel, and increased adiposity, albeit at overall reduced body weight. Our findings highlight a novel concept in regulation of the melanocortin system and the role played by trafficking receptors SORCS1 and SORCS3 in this process.
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Affiliation(s)
| | - Anna R Malik
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Guido Hermey
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Oliver Popp
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Gunnar Dittmar
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany
| | - Thomas Rathjen
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Matthew N Poy
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany
| | - Alexander Stumpf
- Neuroscience Research Center, Charité - University Medicine, Berlin, Germany
| | - Prateep Sanker Beed
- Neuroscience Research Center, Charité - University Medicine, Berlin, Germany
| | - Dietmar Schmitz
- Neuroscience Research Center, Charité - University Medicine, Berlin, Germany
| | | | - Thomas E Willnow
- Max-Delbrueck-Center for Molecular Medicine, Berlin, Germany .,Berlin Institute of Health, Berlin, Germany
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21
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Abstract
Hypothalamic integration of gastrointestinal and adipose tissue-derived hormones serves as a key element of neuroendocrine control of food intake. Leptin, adiponectin, oleoylethanolamide, cholecystokinin, and ghrelin, to name a few, are in a constant "cross talk" with the feeding-related brain circuits that encompass hypothalamic populations synthesizing anorexigens (melanocortins, CART, oxytocin) and orexigens (Agouti-related protein, neuropeptide Y, orexins). While this integrated neuroendocrine circuit successfully ensures that enough energy is acquired, it does not seem to be equally efficient in preventing excessive energy intake, especially in the obesogenic environment in which highly caloric and palatable food is constantly available. The current review presents an overview of intricate mechanisms underlying hypothalamic integration of energy balance-related peripheral endocrine input. We discuss vulnerabilities and maladaptive neuroregulatory processes, including changes in hypothalamic neuronal plasticity that propel overeating despite negative consequences.
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22
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Thomas MA, Xue B. Mechanisms for AgRP neuron-mediated regulation of appetitive behaviors in rodents. Physiol Behav 2017; 190:34-42. [PMID: 29031550 DOI: 10.1016/j.physbeh.2017.10.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 08/29/2017] [Accepted: 10/06/2017] [Indexed: 12/19/2022]
Abstract
The obesity epidemic is a major health and economic burden facing both developed and developing countries worldwide. Interrogation of the central and peripheral mechanisms regulating ingestive behaviors have primarily focused on food intake, and in the process uncovered a detailed neuroanatomical framework controlling this behavior. However, these studies have largely ignored the behaviors that bring animals, including humans, in contact with food. It is therefore useful to dichotomize ingestive behaviors as appetitive (motivation to find and store food) and consummatory (consumption of food once found), and utilize an animal model that naturally displays these behaviors. Recent advances in genetics have facilitated the identification of several neuronal populations critical for regulating ingestive behaviors in mice, and novel functions of these neurons and neuropeptides in regulating appetitive behaviors in Siberian hamsters, a natural model of food foraging and food hoarding, have been identified. To this end, hypothalamic agouti-related protein/neuropeptide Y expressing neurons (AgRP neurons) have emerged as a critical regulator of ingestive behaviors. Recent studies by Dr. Timothy Bartness and others have identified several discrete mechanisms through which peripheral endocrine signals regulate AgRP neurons to control food foraging, food hoarding, and food intake. We review here recent advances in our understanding of the neuroendocrine control of ingestive behaviors in Siberian hamsters and other laboratory rodents, and identify novel mechanisms through which AgRP neurons mediate appetitive and consummatory behaviors.
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Affiliation(s)
- M Alex Thomas
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA; Center for Obesity Reversal, Georgia State University, Atlanta, GA 30302, USA
| | - Bingzhong Xue
- Department of Biology, Georgia State University, Atlanta, GA 30302, USA; Center for Obesity Reversal, Georgia State University, Atlanta, GA 30302, USA; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, USA.
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23
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Ericson MD, Lensing CJ, Fleming KA, Schlasner KN, Doering SR, Haskell-Luevano C. Bench-top to clinical therapies: A review of melanocortin ligands from 1954 to 2016. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2414-2435. [PMID: 28363699 PMCID: PMC5600687 DOI: 10.1016/j.bbadis.2017.03.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/21/2017] [Accepted: 03/27/2017] [Indexed: 10/19/2022]
Abstract
The discovery of the endogenous melanocortin agonists in the 1950s have resulted in sixty years of melanocortin ligand research. Early efforts involved truncations or select modifications of the naturally occurring agonists leading to the development of many potent and selective ligands. With the identification and cloning of the five known melanocortin receptors, many ligands were improved upon through bench-top in vitro assays. Optimization of select properties resulted in ligands adopted as clinical candidates. A summary of every melanocortin ligand is outside the scope of this review. Instead, this review will focus on the following topics: classic melanocortin ligands, selective ligands, small molecule (non-peptide) ligands, ligands with sex-specific effects, bivalent and multivalent ligands, and ligands advanced to clinical trials. Each topic area will be summarized with current references to update the melanocortin field on recent progress. This article is part of a Special Issue entitled: Melanocortin Receptors - edited by Ya-Xiong Tao.
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Affiliation(s)
- Mark D Ericson
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Cody J Lensing
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Katlyn A Fleming
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Katherine N Schlasner
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Skye R Doering
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
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25
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Resolving Behavioral Output via Chemogenetic Designer Receptors Exclusively Activated by Designer Drugs. J Neurosci 2017; 36:9268-82. [PMID: 27605603 DOI: 10.1523/jneurosci.1333-16.2016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 07/13/2016] [Indexed: 12/26/2022] Open
Abstract
Designer receptors exclusively activated by designer drugs (DREADDs) have proven to be highly effective neuromodulatory tools for the investigation of neural circuits underlying behavioral outputs. They exhibit a number of advantages: they rely on cell-specific manipulations through canonical intracellular signaling pathways, they are easy and cost-effective to implement in a laboratory setting, and they are easily scalable for single-region or full-brain manipulations. On the other hand, DREADDs rely on ligand-G-protein-coupled receptor interactions, leading to coarse temporal dynamics. In this review we will provide a brief overview of DREADDs, their implementation, and the advantages and disadvantages of their use in animal systems. We also will provide numerous examples of their use across a broad variety of biomedical research fields.
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26
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Huang HH, Chen LY, Doong ML, Chang SC, Chen CY. α-melanocyte stimulating hormone modulates the central acyl ghrelin-induced stimulation of feeding, gastrointestinal motility, and colonic secretion. DRUG DESIGN DEVELOPMENT AND THERAPY 2017; 11:2377-2386. [PMID: 28860709 PMCID: PMC5566386 DOI: 10.2147/dddt.s143749] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Background Acyl ghrelin-induced intake depends on hypothalamic neuropeptide Y and agouti-related protein (AgRP) neurotransmitters. Intracerebroventricular (ICV) injection of AgRP increases feeding through competitive antagonism at melanocortin receptors. ICV administration of α-melanocyte stimulating hormone (α-MSH), a natural antagonist of AgRP, may modulate the acyl ghrelin-induced orexigenic effect. Objective This study aimed to investigate the modulating effect of α-MSH on the central acyl ghrelin-induced food intake, gastrointestinal motility, and colonic secretion in rats. Methods and procedures We examined the effects of α-MSH and acyl ghrelin on food intake, gastric emptying, small intestinal transit, colonic motility, and secretion in conscious rats with a chronic implant of ICV catheters. Results ICV injection of O-n-octanoylated ghrelin (0.1 nmol/rat) significantly increased the cumulative food intake up to 8 h (P<0.01), enhanced non-nutrient semi-liquid gastric emptying (P<0.001), increased the geometric center and running percentage of small intestinal transit (P<0.001), accelerated colonic transit time (P<0.05), and increased fecal pellet output (P<0.01) and total fecal weight (P<0.01). Pretreatment with ICV injection of α-MSH (1.0 and 2.0 nmol/rat) attenuated the acyl ghrelin-induced hyperphagic effect, fecal pellet output, and total fecal weight, while higher dose of α-MSH (2.0 nmol/rat) attenuated the increase in the geometric center of small intestinal transit (P<0.01). However, neither dose of α-MSH altered acyl ghrelin-stimulated gastroprokinetic effect, increase in the running percentage of small intestinal transit, nor accelerated colonic transit time. Conclusion α-MSH is involved in central acyl ghrelin-elicited feeding, small intestinal transit, fecal pellet output, and fecal weight. α-MSH does not affect central acyl ghrelin-induced acceleration of gastric emptying and colonic transit time in rats.
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Affiliation(s)
- Hsien-Hao Huang
- Institute of Clinical Medicine, National Yang-Ming University of Medicine.,Department of Emergency Medicine, Taipei Veterans General Hospital
| | - Liang-Yu Chen
- Aging and Health Research Center, National Yang-Ming University.,Center for Geriatrics and Gerontology, Taipei Veterans General Hospital
| | - Ming-Luen Doong
- Institute of Physiology, National Yang-Ming University School of Medicine
| | - Shi-Chuan Chang
- Institute of Emergency and Critical Medicine, National Yang-Ming University School of Medicine.,Department of Chest Medicine, Taipei Veterans General Hospital
| | - Chih-Yen Chen
- Division of Gastroenterology and Hepatology, Department of Medicine, Taipei Veterans General Hospital.,Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei.,Taiwan Association for the Study of Small Intestinal Diseases, Guishan, Taiwan
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Yang LK, Tao YX. Biased signaling at neural melanocortin receptors in regulation of energy homeostasis. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2486-2495. [PMID: 28433713 DOI: 10.1016/j.bbadis.2017.04.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/09/2017] [Accepted: 04/10/2017] [Indexed: 12/15/2022]
Abstract
The global prevalence of obesity highlights the importance of understanding on regulation of energy homeostasis. The central melanocortin system is an important intersection connecting the neural pathways controlling satiety and energy expenditure to regulate energy homeostasis by sensing and integrating the signals of external stimuli. In this system, neural melanocortin receptors (MCRs), melanocortin-3 and -4 receptors (MC3R and MC4R), play crucial roles in the regulation of energy homeostasis. Recently, multiple intracellular signaling pathways and biased signaling at neural MCRs have been discovered, providing new insights into neural MCR signaling. This review attempts to summarize biased signaling including biased receptor mutants (both naturally occurring and lab-generated) and biased ligands at neural MCRs, and to provide a better understanding of obesity pathogenesis and new therapeutic implications for obesity treatment.
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Affiliation(s)
- Li-Kun Yang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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28
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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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Chen Y, Lin YC, Zimmerman CA, Essner RA, Knight ZA. Hunger neurons drive feeding through a sustained, positive reinforcement signal. eLife 2016; 5. [PMID: 27554486 PMCID: PMC5016090 DOI: 10.7554/elife.18640] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/23/2016] [Indexed: 01/22/2023] Open
Abstract
The neural mechanisms underlying hunger are poorly understood. AgRP neurons are activated by energy deficit and promote voracious food consumption, suggesting these cells may supply the fundamental hunger drive that motivates feeding. However recent in vivo recording experiments revealed that AgRP neurons are inhibited within seconds by the sensory detection of food, raising the question of how these cells can promote feeding at all. Here we resolve this paradox by showing that brief optogenetic stimulation of AgRP neurons before food availability promotes intense appetitive and consummatory behaviors that persist for tens of minutes in the absence of continued AgRP neuron activation. We show that these sustained behavioral responses are mediated by a long-lasting potentiation of the rewarding properties of food and that AgRP neuron activity is positively reinforcing. These findings reveal that hunger neurons drive feeding by transmitting a positive valence signal that triggers a stable transition between behavioral states. DOI:http://dx.doi.org/10.7554/eLife.18640.001
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Affiliation(s)
- Yiming Chen
- Department of Physiology, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States.,Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United states
| | - Yen-Chu Lin
- Department of Physiology, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Christopher A Zimmerman
- Department of Physiology, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States.,Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United states
| | - Rachel A Essner
- Department of Physiology, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Zachary A Knight
- Department of Physiology, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States.,Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United states
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Gustavsson C, Andersson Hall U, Pelanis A, Karlsson OI, Andersson L, Svedin P, Mallard C, Myntti A, Andreasson U, Zetterberg H, Blennow K, Holmäng A. Cerebrospinal fluid levels of insulin, leptin, and agouti-related protein in relation to BMI in pregnant women. Obesity (Silver Spring) 2016; 24:1299-304. [PMID: 27130070 DOI: 10.1002/oby.21502] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 02/14/2016] [Indexed: 12/31/2022]
Abstract
OBJECTIVE During pregnancy, metabolic interactions must be adapted, though neuroendocrine mechanisms for increased food intake are poorly understood. The objective of this study was to characterize differences in insulin, leptin, and agouti-related protein (AgRP) levels in serum and cerebrospinal fluid (CSF) in pregnant women with normal weight (NW) and pregnant women with overweight (OW) or obesity (OB). Placenta as a source for increased peripheral AgRP levels during pregnancy was also investigated. METHODS Women were recruited at admission for elective cesarean section. Insulin, AgRP, and leptin were measured in serum and CSF from 30 NW, 25 OW, and 21 OB at term. Serum during pregnancy and placenta at term were collected for further AgRP analysis. RESULTS Immunohistology showed placental production of AgRP and serum AgRP levels increased throughout pregnancy. CSF AgRP, leptin, and insulin levels were higher in OW and OB than NW. Serum leptin and insulin levels were higher and AgRP lower in OB than NW. CONCLUSIONS High serum AgRP levels might protect from the suppressive effects of leptin during pregnancy. Pregnant women with OB and OW might further be protected from the suppressive effect of leptin by high CSF AgRP levels. Evidence was found, for the first time, of human placental AgRP production mirrored by levels in the circulation.
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Affiliation(s)
- Carolina Gustavsson
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Ulrika Andersson Hall
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Aurimantas Pelanis
- Department of Anesthesiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Ove I Karlsson
- Department of Anesthesiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Louise Andersson
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Pernilla Svedin
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Carina Mallard
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Alexandra Myntti
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Ulf Andreasson
- Clinical Neurochemistry Lab, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden
| | - Henrik Zetterberg
- Clinical Neurochemistry Lab, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden
- UCL Institute of Neurology, London, UK
| | - Kaj Blennow
- Clinical Neurochemistry Lab, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden
| | - Agneta Holmäng
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
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31
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Yang Z, Tao YX. Biased signaling initiated by agouti-related peptide through human melanocortin-3 and -4 receptors. Biochim Biophys Acta Mol Basis Dis 2016; 1862:1485-94. [PMID: 27208795 DOI: 10.1016/j.bbadis.2016.05.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 05/09/2016] [Accepted: 05/16/2016] [Indexed: 01/01/2023]
Abstract
The neural melanocortin receptors (MCRs), melanocortin-3 and -4 receptors (MC3R and MC4R), have been increasingly recognized as important regulators of energy homeostasis. The orexigenic agouti-related peptide (AgRP), initially identified as an endogenous antagonist for both neural MCRs, has been suggested to be a biased agonist of MC4R independent of its antagonizing effects. In the present study, we sought to determine the potential of AgRP to regulate the activation of intracellular kinases, including extracellular signal-regulated kinase 1 and 2 (ERK1/2), AKT and AMP-activated protein kinase (AMPK), through neural MCRs. We showed that AgRP acted as a biased agonist in human MC3R (hMC3R), decreasing cAMP activity of constitutively active mutant (F347A) hMC3R but stimulating ERK1/2 activation in both wide type and F347A hMC3Rs. AgRP-stimulated ERK1/2 phosphorylation through MC3R was abolished by protein kinase A (PKA) inhibitor H-89 but not Rp-cAMPS, whereas AgRP-initiated ERK1/2 activation through MC4R was inhibited by phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and LY294002. Both NDP-MSH and AgRP treatment induced significant AKT phosphorylation in GT1-7 cells but not in MC3R- or MC4R-transfected HEK293T cells. The phosphorylated AMPK levels in both GT1-7 cells and HERK293T cells transfected with neural MCRs were significantly decreased upon stimulation with NDP-MSH but not with AgRP. In summary, we provided novel data for AgRP-initiated multiple intracellular signaling pathways, demonstrating biased agonism of AgRP in both neural MCRs, leading to a better understanding of neural MCR pharmacology.
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MESH Headings
- AMP-Activated Protein Kinases/metabolism
- Agouti-Related Protein/metabolism
- Amino Acid Substitution
- Central Nervous System/metabolism
- Cyclic AMP/metabolism
- HEK293 Cells
- Humans
- Kinetics
- Ligands
- MAP Kinase Signaling System
- Mutagenesis, Site-Directed
- Peptide Fragments/metabolism
- Proto-Oncogene Proteins c-akt/metabolism
- Receptor, Melanocortin, Type 3/agonists
- Receptor, Melanocortin, Type 3/genetics
- Receptor, Melanocortin, Type 3/metabolism
- Receptor, Melanocortin, Type 4/agonists
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Signal Transduction
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Affiliation(s)
- Zhao Yang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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32
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Yi J, Delp MS, Gilbert ER, Siegel PB, Cline MA. Anorexia is Associated with Stress-Dependent Orexigenic Responses to Exogenous Neuropeptide Y. J Neuroendocrinol 2016; 28. [PMID: 26924179 DOI: 10.1111/jne.12378] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 02/22/2016] [Accepted: 02/23/2016] [Indexed: 11/28/2022]
Abstract
Chicken lines that have been divergently selected for either low (LWS) or high (HWS) body weight at 56 days of age for more than 57 generations have different feeding behaviours in response to a range of i.c.v. injected neurotransmitters. The LWS have different severities of anorexia, whereas the HWS become obese. Previously, we demonstrated that LWS chicks did not respond, whereas HWS chicks increased food intake, after central injection of neuropeptide Y (NPY). The present study aimed to determine the molecular mechanisms underlying the loss of orexigenic function of NPY in LWS. Chicks were divided into four groups: stressed LWS and HWS on day of hatch, and control LWS and HWS. The stressor was a combination of food deprivation and cold exposure. On day 5 post-hatch, each chick received an i.c.v. injection of vehicle or 0.2 nmol of NPY. Only the LWS stressed group did not increase food intake in response to i.c.v. NPY. Hypothalamic mRNA abundance of appetite-associated factors was measured at 1 h post-injection. Interactions of genetic line, stress and NPY treatment were observed for the mRNA abundance of agouti-related peptide (AgRP) and synaptotagmin 1 (SYT1). Intracerebroventricular injection of NPY decreased and increased AgRP and SYT1 mRNA, respectively, in the stressed LWS and increased AgRP mRNA in stressed HWS chicks. Stress was associated with increased NPY, orexin receptor 2, corticotrophin-releasing factor receptor 1, melanocortin receptor 3 (MC3R) and growth hormone secretagogue receptor expression. In conclusion, the loss of responsiveness to exogenous NPY in stressed LWS chicks may be a result of the decreased and increased hypothalamic expression of AgRP and MC3R, respectively. This may induce an intensification of anorexigenic melanocortin signalling pathways in LWS chicks that block the orexigenic effect of exogenous NPY. These results provide insights onto the anorexic condition across species, and especially for forms of inducible anorexia such as human anorexia nervosa.
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Affiliation(s)
- J Yi
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - M S Delp
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - E R Gilbert
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - P B Siegel
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - M A Cline
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
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33
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Webber ES, Bonci A, Krashes MJ. The elegance of energy balance: Insight from circuit-level manipulations. Synapse 2016; 69:461-74. [PMID: 26126768 DOI: 10.1002/syn.21837] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/08/2015] [Accepted: 06/16/2015] [Indexed: 01/24/2023]
Abstract
Mechanisms of energy balance were first examined using very powerful neuroscience techniques such as lesions and electrical stimulation. This early work identified the hypothalamus as a key structure involved in hunger and feeding; however, neural resolution of cell-defined populations contributing to appetite regulation remained elusive. Recent innovations in neuroscience have produced constructs that allow for a high degree of specificity in loss- and gain-of-function manipulations in molecularly circumscribed neural subsets as well as monosynaptic circuit mapping and in vivo neurophysiology. These complimentary techniques have provided researchers an unprecedented amount of empirical agility. As a result, cell populations in two subregions of the hypothalamus have emerged as key players in the physiological control of feeding behavior. The arcuate nucleus of the hypothalamus and the paraventricular nucleus of the hypothalamus contain neural populations that have a direct role in the promotion of hunger and satiety. These include neurons that express agouti-related peptide, pro-opiomelanocortin, single-minded homolog 1 protein, and the melanocortin-4 receptor. This review focuses on how these neural subsets communicate with one another, link up to build elaborate networks, and ultimately contribute to alterations in food intake. The continuing advancement of neuroscience tools, as well as a multimodal integration of findings, will be critical in illuminating an exhaustive and clinically relevant hunger circuit.
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Affiliation(s)
- Emily S Webber
- Digestive and Kidney Diseases, Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes, National Institutes of Health, Bethesda, Maryland
| | - Antonello Bonci
- National Institute of Drug Abuse, National Institutes of Health, Baltimore, Maryland
| | - Michael J Krashes
- Digestive and Kidney Diseases, Diabetes, Endocrinology and Obesity Branch, National Institute of Diabetes, National Institutes of Health, Bethesda, Maryland.,National Institute of Drug Abuse, National Institutes of Health, Baltimore, Maryland
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34
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Ameliorating antipsychotic-induced weight gain by betahistine: Mechanisms and clinical implications. Pharmacol Res 2016; 106:51-63. [DOI: 10.1016/j.phrs.2016.02.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 02/08/2016] [Accepted: 02/11/2016] [Indexed: 01/08/2023]
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Abstract
AgRP and POMC neurons are two key cell types that regulate feeding in response to hormones and nutrients. Recently, it was discovered that these neurons are also rapidly modulated by the mere sight and smell of food. This rapid sensory regulation "resets" the activity of AgRP and POMC neurons before a single bite of food has been consumed. This surprising and counterintuitive discovery challenges longstanding assumptions about the function and regulation of these cells. Here we review these recent findings and discuss their implications for our understanding of feeding behavior. We propose several alternative hypotheses for how these new observations might be integrated into a revised model of the feeding circuit, and also highlight some of the key questions that remain to be answered.
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Affiliation(s)
- Yiming Chen
- Department of Physiology, University of California, San Francisco, CA, USA
| | - Zachary A Knight
- Department of Physiology, University of California, San Francisco, CA, USA
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36
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Food intake inhibition in rainbow trout induced by activation of serotonin 5-HT2C receptors is associated with increases in POMC, CART and CRF mRNA abundance in hypothalamus. J Comp Physiol B 2016; 186:313-21. [PMID: 26832922 DOI: 10.1007/s00360-016-0961-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/05/2016] [Accepted: 01/15/2016] [Indexed: 11/27/2022]
Abstract
In rainbow trout, the food intake inhibition induced by serotonin occurs through 5-HT2C and 5-HT1A receptors, though the mechanisms involved are still unknown. Therefore, we assessed if a direct stimulation of 5-HT2C and 5-HT1A serotonin receptors (resulting in decreased food intake in rainbow trout), affects gene expression of neuropeptides involved in the control of food intake, such as pro-opiomelanocortin (POMC), cocaine- and amphetamine-regulated transcript (CART), corticotrophin releasing factor (CRF), and agouti-related peptide (AgRP). In a first set of experiments, the injection of the 5-HT2C receptor agonists MK212 (60 μg kg(-1) icv) and WAY 161503 (1 mg kg(-1) ip), and of the 5-HT1A receptor agonist 8-OH-DPAT (1 mg kg(-1) ip and 30 μg kg(-1) icv) induced food intake inhibition. In a second set of experiments, we observed that the injection of MK212 or WAY 161503 (1 and 3 mg kg(-1)) significantly increased hypothalamic POMC mRNA abundance. CART mRNA abundance in hypothalamus was enhanced by treatment with MK212 and unaffected by WAY 161503. The administration of the 5-HT1A receptor agonist 8-OH-DPAT did not induce any significant variation in the hypothalamic POMC or CART mRNA levels. CRF mRNA abundance was only affected by MK212 that increased hypothalamic values. Finally, hypothalamic AgRP mRNA abundance was only evaluated with the agonist 5-HT2C MK212 resulting in no significant effects. The results show that the reduction in food intake mediated by 5-HT2C receptors is associated with increases in hypothalamic POMC, CART and CRF mRNA abundance.
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37
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Amyotrophic lateral sclerosis and frontotemporal dementia: distinct and overlapping changes in eating behaviour and metabolism. Lancet Neurol 2016; 15:332-42. [PMID: 26822748 DOI: 10.1016/s1474-4422(15)00380-4] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Revised: 11/17/2015] [Accepted: 12/02/2015] [Indexed: 12/12/2022]
Abstract
Metabolic changes incorporating fluctuations in weight, insulin resistance, and cholesterol concentrations have been identified in several neurodegenerative disorders. Whether these changes result from the neurodegenerative process affecting brain regions necessary for metabolic regulation or whether they drive the degenerative process is unknown. Emerging evidence from epidemiological, clinical, pathological, and experimental studies emphasises a range of changes in eating behaviours and metabolism in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). In ALS, metabolic changes have been linked to disease progression and prognosis. Furthermore, changes in eating behaviour that affect metabolism have been incorporated into the diagnostic criteria for FTD, which has some clinical and pathological overlap with ALS. Whether the distinct and shared metabolic and eating changes represent a component of the proposed spectrum of the two diseases is an intriguing possibility. Moreover, future research should aim to unravel the complex connections between eating, metabolism, and neurodegeneration in ALS and FTD, and aim to understand the potential for targeting modifiable risk factors in disease development and progression.
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38
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Nakajima KI, Cui Z, Li C, Meister J, Cui Y, Fu O, Smith AS, Jain S, Lowell BB, Krashes MJ, Wess J. Gs-coupled GPCR signalling in AgRP neurons triggers sustained increase in food intake. Nat Commun 2016; 7:10268. [PMID: 26743492 PMCID: PMC4729878 DOI: 10.1038/ncomms10268] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Accepted: 11/24/2015] [Indexed: 01/06/2023] Open
Abstract
Agouti-related peptide (AgRP) neurons of the hypothalamus play a key role in regulating food intake and body weight, by releasing three different orexigenic molecules: AgRP; GABA; and neuropeptide Y. AgRP neurons express various G protein-coupled receptors (GPCRs) with different coupling properties, including Gs-linked GPCRs. At present, the potential role of Gs-coupled GPCRs in regulating the activity of AgRP neurons remains unknown. Here we show that the activation of Gs-coupled receptors expressed by AgRP neurons leads to a robust and sustained increase in food intake. We also provide detailed mechanistic data linking the stimulation of this class of receptors to the observed feeding phenotype. Moreover, we show that this pathway is clearly distinct from other GPCR signalling cascades that are operative in AgRP neurons. Our data suggest that drugs able to inhibit this signalling pathway may become useful for the treatment of obesity. Hypothalamic Agouti-related peptide (AgRP) neurons play a key role in regulating food intake. Here, the authors report a novel pathway in which activation of Gs-coupled receptors on AgRP neurons leads to robust, sustained increase in food intake.
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Affiliation(s)
- Ken-ichiro Nakajima
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Zhenzhong Cui
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Chia Li
- Diabetes Endocrine and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Jaroslawna Meister
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Yinghong Cui
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Ou Fu
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 1138657, Japan
| | - Adam S Smith
- Section on Neural Gene Expression, National Institute of Mental Health, Bethesda, Maryland 20892, USA
| | - Shalini Jain
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Bradford B Lowell
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Michael J Krashes
- Diabetes Endocrine and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Jürgen Wess
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
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Abstract
Although it has been known for more than a century that the brain controls overall energy balance and adiposity by regulating feeding behavior and energy expenditure, the roles for individual brain regions and neuronal subtypes were not fully understood until recently. This area of research is active, and as such our understanding of the central regulation of energy balance is continually being refined as new details emerge. Much of what we now know stems from the discoveries of leptin and the hypothalamic melanocortin system. Hypothalamic circuits play a crucial role in the control of feeding and energy expenditure, and within the hypothalamus, the arcuate nucleus (ARC) functions as a gateway for hormonal signals of energy balance, such as leptin. It is also well established that the ARC is a primary residence for hypothalamic melanocortinergic neurons. The paraventricular hypothalamic nucleus (PVH) receives direct melanocortin input, along with other integrated signals that affect energy balance, and mediates the majority of hypothalamic output to control both feeding and energy expenditure. Herein, we review in detail the structure and function of the ARC-PVH circuit in mediating leptin signaling and in regulating energy balance.
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Affiliation(s)
- Amy K Sutton
- Departments of Internal Medicine and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48105;
- Division of Endocrinology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan 48105;
| | - Martin G Myers
- Departments of Internal Medicine and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48105;
| | - David P Olson
- Division of Endocrinology, Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan 48105;
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Hirono S, Lee EY, Kuribayashi S, Fukuda T, Saeki N, Minokoshi Y, Iwanaga T, Miki T. Importance of Adult Dmbx1 in Long-Lasting Orexigenic Effect of Agouti-Related Peptide. Endocrinology 2016; 157:245-57. [PMID: 26505115 DOI: 10.1210/en.2015-1560] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dmbx1 is a brain-specific homeodomain transcription factor expressed primarily during embryogenesis, and its systemic disruption (Dmbx1(-/-)) in the ICR mouse strain resulted in leanness associated with impaired long-lasting orexigenic effect of agouti-related peptide (AgRP). Because spatial and temporal expression patterns of Dmbx1 change dramatically during embryogenesis, it remains unknown when and where Dmbx1 plays a critical role in energy homeostasis. In the present study, the physiological roles of Dmbx1 were examined by its conditional disruption (Dmbx1(loxP/loxP)) in the C57BL/6 mouse strain. Although Dmbx1 disruption in fetal brain resulted in neonatal lethality, its disruption by synapsin promoter-driven Cre recombinase, which eliminated Dmbx1 expression postnatally, exempted the mice (Syn-Cre;Dmbx1(loxP/loxP) mice) from lethality. Syn-Cre;Dmbx1(loxP/loxP) mice show mild leanness and impaired long-lasting orexigenic action of AgRP, demonstrating the physiological relevance of Dmbx1 in the adult. Visualization of Dmbx1-expressing neurons in adult brain using the mice harboring tamoxifen-inducible Cre recombinase in the Dmbx1 locus (Dmbx1(CreERT2/+) mice) revealed Dmbx1 expression in small numbers of neurons in restricted regions, including the lateral parabrachial nucleus (LPB). Notably, c-Fos expression in LPB was increased at 48 hours after AgRP administration in Dmbx1(loxP/loxP) mice but not in Syn-Cre;Dmbx1(loxP/loxP) mice. These c-Fos-positive neurons in LPB did not coincide with neurons expressing Dmbx1 or melanocortin 4 receptor but did coincide with those expressing calcitonin gene-related peptide. Accordingly, Dmbx1 in the adult LPB is required for the long-lasting orexigenic effect of AgRP via the neural circuitry involving calcitonin gene-related peptide neurons.
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Affiliation(s)
- Seiichiro Hirono
- Departments of Medical Physiology (S.H., E.Y.L., S.K., T.M.) and Neurological Surgery (S.H., N.S.), Chiba University Graduate School of Medicine, Chuo-ku, Chiba, 260-0856, Japan; Division of Neuropathology (T.F.), Department of Pathology, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-0003, Japan; Department of Developmental Physiology (Y.M.), National Institute for Physiological Sciences, Myoudaijicho, Okazaki-City, 444-8585, Japan; and Laboratory of Histology and Cytology (T.I.), Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo 060-8638, Japan
| | - Eun Young Lee
- Departments of Medical Physiology (S.H., E.Y.L., S.K., T.M.) and Neurological Surgery (S.H., N.S.), Chiba University Graduate School of Medicine, Chuo-ku, Chiba, 260-0856, Japan; Division of Neuropathology (T.F.), Department of Pathology, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-0003, Japan; Department of Developmental Physiology (Y.M.), National Institute for Physiological Sciences, Myoudaijicho, Okazaki-City, 444-8585, Japan; and Laboratory of Histology and Cytology (T.I.), Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo 060-8638, Japan
| | - Shunsuke Kuribayashi
- Departments of Medical Physiology (S.H., E.Y.L., S.K., T.M.) and Neurological Surgery (S.H., N.S.), Chiba University Graduate School of Medicine, Chuo-ku, Chiba, 260-0856, Japan; Division of Neuropathology (T.F.), Department of Pathology, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-0003, Japan; Department of Developmental Physiology (Y.M.), National Institute for Physiological Sciences, Myoudaijicho, Okazaki-City, 444-8585, Japan; and Laboratory of Histology and Cytology (T.I.), Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo 060-8638, Japan
| | - Takahiro Fukuda
- Departments of Medical Physiology (S.H., E.Y.L., S.K., T.M.) and Neurological Surgery (S.H., N.S.), Chiba University Graduate School of Medicine, Chuo-ku, Chiba, 260-0856, Japan; Division of Neuropathology (T.F.), Department of Pathology, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-0003, Japan; Department of Developmental Physiology (Y.M.), National Institute for Physiological Sciences, Myoudaijicho, Okazaki-City, 444-8585, Japan; and Laboratory of Histology and Cytology (T.I.), Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo 060-8638, Japan
| | - Naokatsu Saeki
- Departments of Medical Physiology (S.H., E.Y.L., S.K., T.M.) and Neurological Surgery (S.H., N.S.), Chiba University Graduate School of Medicine, Chuo-ku, Chiba, 260-0856, Japan; Division of Neuropathology (T.F.), Department of Pathology, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-0003, Japan; Department of Developmental Physiology (Y.M.), National Institute for Physiological Sciences, Myoudaijicho, Okazaki-City, 444-8585, Japan; and Laboratory of Histology and Cytology (T.I.), Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo 060-8638, Japan
| | - Yasuhiko Minokoshi
- Departments of Medical Physiology (S.H., E.Y.L., S.K., T.M.) and Neurological Surgery (S.H., N.S.), Chiba University Graduate School of Medicine, Chuo-ku, Chiba, 260-0856, Japan; Division of Neuropathology (T.F.), Department of Pathology, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-0003, Japan; Department of Developmental Physiology (Y.M.), National Institute for Physiological Sciences, Myoudaijicho, Okazaki-City, 444-8585, Japan; and Laboratory of Histology and Cytology (T.I.), Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo 060-8638, Japan
| | - Toshihiko Iwanaga
- Departments of Medical Physiology (S.H., E.Y.L., S.K., T.M.) and Neurological Surgery (S.H., N.S.), Chiba University Graduate School of Medicine, Chuo-ku, Chiba, 260-0856, Japan; Division of Neuropathology (T.F.), Department of Pathology, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-0003, Japan; Department of Developmental Physiology (Y.M.), National Institute for Physiological Sciences, Myoudaijicho, Okazaki-City, 444-8585, Japan; and Laboratory of Histology and Cytology (T.I.), Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo 060-8638, Japan
| | - Takashi Miki
- Departments of Medical Physiology (S.H., E.Y.L., S.K., T.M.) and Neurological Surgery (S.H., N.S.), Chiba University Graduate School of Medicine, Chuo-ku, Chiba, 260-0856, Japan; Division of Neuropathology (T.F.), Department of Pathology, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-0003, Japan; Department of Developmental Physiology (Y.M.), National Institute for Physiological Sciences, Myoudaijicho, Okazaki-City, 444-8585, Japan; and Laboratory of Histology and Cytology (T.I.), Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo 060-8638, Japan
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Ahmed RM, Latheef S, Bartley L, Irish M, Halliday GM, Kiernan MC, Hodges JR, Piguet O. Eating behavior in frontotemporal dementia: Peripheral hormones vs hypothalamic pathology. Neurology 2015; 85:1310-7. [PMID: 26377252 DOI: 10.1212/wnl.0000000000002018] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 06/08/2015] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVE To contrast the relationships of hormonal eating peptides and hypothalamic volumes to eating behavior and metabolic changes (body mass index [BMI]) in behavioral variant frontotemporal dementia (bvFTD) and semantic variant primary progressive aphasia (svPPA). METHODS Seventy-five patients with dementia (19 bvFTD, 26 svPPA, and 30 Alzheimer disease dementia) and 23 controls underwent fasting blood analyses of leptin, ghrelin, cholecystokinin, peptide tyrosine tyrosine (PYY), and agouti-related peptide (AgRP) levels. On brain MRI anterior, posterior, and total hypothalamic volumes were measured. Relationships between endocrine measures, hypothalamic volumes, eating behaviors, and BMI were investigated. RESULTS Levels of AgRP were higher in patients with bvFTD (69 ± 89 pg/mL) and svPPA (62 ± 81 pg/mL) compared with controls (23 ± 19 pg/mL, p < 0.01). No differences were found for leptin, oxytocin, cholecystokinin, ghrelin, and PYY levels. Patients with bvFTD and svPPA had higher scores on questionnaires measuring eating behaviors. Atrophy of the posterior and total hypothalamus was observed in the bvFTD group only. Linear regression modeling revealed that leptin and AgRP levels predicted BMI. CONCLUSION Eating abnormalities are multifactorial in FTD. In bvFTD, they are in part related to hypothalamic degeneration, with potential disintegration of the network connections between the hypothalamus and orbitofrontal cortex/reward pathways. In svPPA, although hypothalamic volumes are preserved, this group experiences elevated AgRP levels similar to bvFTD, which predicts BMI in both groups. This finding highlights the potential key role of AgRP in eating and metabolic changes and provides a potential target for treatment to modify disease progression.
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Affiliation(s)
- Rebekah M Ahmed
- From Neuroscience Research Australia (R.M.A., S.L., L.B., M.I., G.M.H., M.C.K., J.R.H., O.P.), Sydney; Prince of Wales Clinical School (R.M.A.), School of Medical Sciences (G.M.H., J.R.H., O.P.), School of Psychology (M.I.), and ARC Centre of Excellence in Cognition and Its Disorders (R.M.A., M.I., J.R.H., O.P.), the University of New South Wales, Sydney; and Sydney Medical School (M.C.K.), Brain and Mind Centre, University of Sydney, Australia.
| | - Sahar Latheef
- From Neuroscience Research Australia (R.M.A., S.L., L.B., M.I., G.M.H., M.C.K., J.R.H., O.P.), Sydney; Prince of Wales Clinical School (R.M.A.), School of Medical Sciences (G.M.H., J.R.H., O.P.), School of Psychology (M.I.), and ARC Centre of Excellence in Cognition and Its Disorders (R.M.A., M.I., J.R.H., O.P.), the University of New South Wales, Sydney; and Sydney Medical School (M.C.K.), Brain and Mind Centre, University of Sydney, Australia
| | - Lauren Bartley
- From Neuroscience Research Australia (R.M.A., S.L., L.B., M.I., G.M.H., M.C.K., J.R.H., O.P.), Sydney; Prince of Wales Clinical School (R.M.A.), School of Medical Sciences (G.M.H., J.R.H., O.P.), School of Psychology (M.I.), and ARC Centre of Excellence in Cognition and Its Disorders (R.M.A., M.I., J.R.H., O.P.), the University of New South Wales, Sydney; and Sydney Medical School (M.C.K.), Brain and Mind Centre, University of Sydney, Australia
| | - Muireann Irish
- From Neuroscience Research Australia (R.M.A., S.L., L.B., M.I., G.M.H., M.C.K., J.R.H., O.P.), Sydney; Prince of Wales Clinical School (R.M.A.), School of Medical Sciences (G.M.H., J.R.H., O.P.), School of Psychology (M.I.), and ARC Centre of Excellence in Cognition and Its Disorders (R.M.A., M.I., J.R.H., O.P.), the University of New South Wales, Sydney; and Sydney Medical School (M.C.K.), Brain and Mind Centre, University of Sydney, Australia
| | - Glenda M Halliday
- From Neuroscience Research Australia (R.M.A., S.L., L.B., M.I., G.M.H., M.C.K., J.R.H., O.P.), Sydney; Prince of Wales Clinical School (R.M.A.), School of Medical Sciences (G.M.H., J.R.H., O.P.), School of Psychology (M.I.), and ARC Centre of Excellence in Cognition and Its Disorders (R.M.A., M.I., J.R.H., O.P.), the University of New South Wales, Sydney; and Sydney Medical School (M.C.K.), Brain and Mind Centre, University of Sydney, Australia
| | - Matthew C Kiernan
- From Neuroscience Research Australia (R.M.A., S.L., L.B., M.I., G.M.H., M.C.K., J.R.H., O.P.), Sydney; Prince of Wales Clinical School (R.M.A.), School of Medical Sciences (G.M.H., J.R.H., O.P.), School of Psychology (M.I.), and ARC Centre of Excellence in Cognition and Its Disorders (R.M.A., M.I., J.R.H., O.P.), the University of New South Wales, Sydney; and Sydney Medical School (M.C.K.), Brain and Mind Centre, University of Sydney, Australia
| | - John R Hodges
- From Neuroscience Research Australia (R.M.A., S.L., L.B., M.I., G.M.H., M.C.K., J.R.H., O.P.), Sydney; Prince of Wales Clinical School (R.M.A.), School of Medical Sciences (G.M.H., J.R.H., O.P.), School of Psychology (M.I.), and ARC Centre of Excellence in Cognition and Its Disorders (R.M.A., M.I., J.R.H., O.P.), the University of New South Wales, Sydney; and Sydney Medical School (M.C.K.), Brain and Mind Centre, University of Sydney, Australia
| | - Olivier Piguet
- From Neuroscience Research Australia (R.M.A., S.L., L.B., M.I., G.M.H., M.C.K., J.R.H., O.P.), Sydney; Prince of Wales Clinical School (R.M.A.), School of Medical Sciences (G.M.H., J.R.H., O.P.), School of Psychology (M.I.), and ARC Centre of Excellence in Cognition and Its Disorders (R.M.A., M.I., J.R.H., O.P.), the University of New South Wales, Sydney; and Sydney Medical School (M.C.K.), Brain and Mind Centre, University of Sydney, Australia.
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42
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Tulloch AJ, Murray S, Vaicekonyte R, Avena NM. Neural responses to macronutrients: hedonic and homeostatic mechanisms. Gastroenterology 2015; 148:1205-18. [PMID: 25644095 DOI: 10.1053/j.gastro.2014.12.058] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 12/16/2014] [Accepted: 12/22/2014] [Indexed: 01/15/2023]
Abstract
The brain responds to macronutrients via intricate mechanisms. We review how the brain's neural systems implicated in homeostatic control of feeding and hedonic responses are influenced by the ingestion of specific types of food. We discuss how these neural systems are dysregulated in preclinical models of obesity. Findings from these studies can increase our understanding of overeating and, perhaps in some cases, the development of obesity. In addition, a greater understanding of the neural circuits affected by the consumption of specific macronutrients, and by obesity, might lead to new treatments and strategies for preventing unhealthy weight gain.
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Affiliation(s)
- Alastair J Tulloch
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York
| | - Susan Murray
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York
| | - Regina Vaicekonyte
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York
| | - Nicole M Avena
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York.
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43
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Betley JN, Xu S, Cao ZFH, Gong R, Magnus CJ, Yu Y, Sternson SM. Neurons for hunger and thirst transmit a negative-valence teaching signal. Nature 2015; 521:180-185. [PMID: 25915020 PMCID: PMC4567040 DOI: 10.1038/nature14416] [Citation(s) in RCA: 431] [Impact Index Per Article: 47.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 03/19/2015] [Indexed: 12/18/2022]
Abstract
Homeostasis is a biological principle for regulation of essential physiological parameters within a set range. Behavioural responses due to deviation from homeostasis are critical for survival, but motivational processes engaged by physiological need states are incompletely understood. We examined motivational characteristics and dynamics of two separate neuron populations that regulate energy and fluid homeostasis by using cell type-specific activity manipulations in mice. We found that starvation-sensitive AGRP neurons exhibit properties consistent with a negative-valence teaching signal. Mice avoided activation of AGRP neurons, indicating that AGRP neuron activity has negative valence. AGRP neuron inhibition conditioned preference for flavours and places. Correspondingly, deep-brain calcium imaging revealed that AGRP neuron activity rapidly reduced in response to food-related cues. Complementary experiments activating thirst-promoting neurons also conditioned avoidance. Therefore, these need-sensing neurons condition preference for environmental cues associated with nutrient or water ingestion, which is learned through reduction of negative-valence signals during restoration of homeostasis.
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Affiliation(s)
- J Nicholas Betley
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Shengjin Xu
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Zhen Fang Huang Cao
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Rong Gong
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Christopher J Magnus
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Yang Yu
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Scott M Sternson
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
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Gali Ramamoorthy T, Begum G, Harno E, White A. Developmental programming of hypothalamic neuronal circuits: impact on energy balance control. Front Neurosci 2015; 9:126. [PMID: 25954145 PMCID: PMC4404811 DOI: 10.3389/fnins.2015.00126] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 03/26/2015] [Indexed: 01/08/2023] Open
Abstract
The prevalence of obesity in adults and children has increased globally at an alarming rate. Mounting evidence from both epidemiological studies and animal models indicates that adult obesity and associated metabolic disorders can be programmed by intrauterine and early postnatal environment- a phenomenon known as "fetal programming of adult disease." Data from nutritional intervention studies in animals including maternal under- and over-nutrition support the developmental origins of obesity and metabolic syndrome. The hypothalamic neuronal circuits located in the arcuate nucleus controlling appetite and energy expenditure are set early in life and are perturbed by maternal nutritional insults. In this review, we focus on the effects of maternal nutrition in programming permanent changes in these hypothalamic circuits, with experimental evidence from animal models of maternal under- and over-nutrition. We discuss the epigenetic modifications which regulate hypothalamic gene expression as potential molecular mechanisms linking maternal diet during pregnancy to the offspring's risk of obesity at a later age. Understanding these mechanisms in key metabolic genes may provide insights into the development of preventative intervention strategies.
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Affiliation(s)
| | - Ghazala Begum
- School of Clinical and Experimental Medicine, University of Birmingham Birmingham, UK
| | - Erika Harno
- Faculty of Life Sciences, University of Manchester Manchester, UK
| | - Anne White
- Faculty of Life Sciences, University of Manchester Manchester, UK ; Faculty of Medical and Human Sciences, Centre for Endocrinology and Diabetes, University of Manchester Manchester, UK
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45
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Wysokiński A, Kaźmierski J, Kłoszewska I. Serum levels of AgRP protein in patients with schizophrenia on clozapine monotherapy. Metab Brain Dis 2015; 30:529-35. [PMID: 25034457 PMCID: PMC4351436 DOI: 10.1007/s11011-014-9592-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 07/07/2014] [Indexed: 01/08/2023]
Abstract
AIM Agouti-related peptide (AgRP) is one of the hypothalamic hormones that works by increasing appetite and decreasing metabolism, thus leading to weight gain. The aim of the study was to find out if AgRP level in subjects with schizophrenia on clozapine monotherapy is higher compared with healthy controls. METHODOLOGY We determined fasting serum AgRP levels in 24 subjects with schizophrenia on clozapine monotherapy and 24 healthy, age- and sex-matched controls. Biochemical and anthropometric measurements were combined with body composition analysis. RESULTS There was no difference for AgRP levels between patients taking clozapine and control group (15.00±8.65 vs. 15.33±6.82 pg/mL, p =0.37). We found negative correlations between AgRP levels and total body fat (r =-0.34 and -0.48 in the whole study group and clozapine group, respectively) and positive correlations with lean body mass (r =0.38 and 0.49 in the whole study group and clozapine group, respectively), body water (r =0.34 and 0.49 in the whole study group and clozapine group, respectively) and basal metabolic rate (r =0.42 both in the clozapine and control groups). There were no correlations with age, height, weight, body mass index, fat mass index, abdominal, waist or hip circumferences, waist-hip ratio, blood pressure, total cholesterol, HDL, LDL, triglycerides, uric acid, glucose, insulin, clozapine dose or treatment duration, duration of treatment with antipsychotics and markers for insulin resistance. CONCLUSION We cannot conclude that treatment with clozapine is associated with increased level of AgRP. We did not find previously described differences in AgRP levels between obese and non-obese subjects or associations between AgRP and various metabolic parameters.
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Affiliation(s)
- Adam Wysokiński
- Department of Old Age Psychiatry and Psychotic Disorders, Medical University of Lodz, Czechosłowacka 8/10, 92-216, Łódź, Poland,
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46
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Tao YX. Constitutive activity in melanocortin-4 receptor: biased signaling of inverse agonists. ADVANCES IN PHARMACOLOGY 2015; 70:135-54. [PMID: 24931195 DOI: 10.1016/b978-0-12-417197-8.00005-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The melanocortin-4 receptor (MC4R) is a critical regulator of energy homeostasis, including both energy intake and energy expenditure. It mediates the actions of a number of hormones on energy balance. The endogenous ligands for MC4R include peptide agonists derived from processing of proopiomelanocortin and the antagonist Agouti-related peptide (AgRP). Wild-type MC4R has some basal (constitutive) activity. Naturally occurring and laboratory-generated mutations have been identified, which results in either increased or decreased basal activities. Impaired basal signaling has been suggested to be a cause of dysregulated energy homeostasis and early-onset obesity, although several constitutively active mutations have also been identified from obese patients. AgRP and several small-molecule antagonists have been shown to be inverse agonists in the Gs-cAMP pathway. However, in the extracellular signal-regulated kinase (ERK) 1/2 pathway, we showed that these inverse agonists are potent agonists, demonstrating convincingly that they are biased ligands. We also showed that some mutations that do not cause constitutive activation in the Gs-cAMP pathway cause constitutive activation in the ERK1/2 pathway, suggesting that they are biased receptors. The physiological and potential pathophysiological relevance of the biased constitutive signaling in MC4R and therapeutic potential remain to be investigated.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA.
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47
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Yen HH, Roseberry AG. Decreased consumption of rewarding sucrose solutions after injection of melanocortins into the ventral tegmental area of rats. Psychopharmacology (Berl) 2015; 232:285-94. [PMID: 24985892 DOI: 10.1007/s00213-014-3663-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 06/11/2014] [Indexed: 01/25/2023]
Abstract
RATIONALE The mesolimbic dopamine system is an important component of the neural circuitry controlling reward-related behavior. We have recently shown that the melanocortin peptides decrease normal homeostatic feeding through actions in the ventral tegmental area. It is unknown, however, whether melanocortin peptides can also act on dopamine pathways to regulate hedonic, reward-related aspects of feeding. OBJECTIVES In these studies, we tested whether injection of melanocortin receptor agonists directly into the ventral tegmental area (VTA) affected the intake of appetizing and rewarding sugar solutions in two-bottle choice tests. METHODS Varying doses of the melanocortin receptor agonist, MTII, were injected into the VTA, and the intake of different sugar solutions was measured in two-bottle choice tests to distinguish between potential effects on homeostatic versus hedonic aspects of feeding. In addition, 24-h food intake was measured throughout the experiments. RESULTS Injection of MTII into the VTA dose dependently decreased the intake of 1 and 2 % sucrose solutions and 0.2 % saccharin solutions and decreased 24-h food intake in each study. Although MTII also decreased the intake of a 10 % sucrose solution, MTII appeared to be less potent in rats exposed to 10 % sucrose, as only the highest dose of MTII tested was effective at reducing 10 % sucrose intake and food intake in these rats. CONCLUSIONS These studies demonstrate that melanocortins can act directly in the VTA to control reward-related feeding. Thus, these studies add to the growing body of evidence showing that melanocortins can interact with the mesolimbic dopamine system to regulate multiple reward-related behaviors.
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Affiliation(s)
- Haw-Han Yen
- Department of Biology, Georgia State University, 24 Peachtree Center Ave NE, Suite 430SA, Atlanta, GA, 30303, USA
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48
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Fasting Serum Levels of Neuropeptide Y in Patients With Schizophrenia on Clozapine Monotherapy. Clin Neuropharmacol 2015; 38:18-22. [DOI: 10.1097/wnf.0000000000000062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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49
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Meek TH, Matsen ME, Damian V, Cubelo A, Chua SC, Morton GJ. Role of melanocortin signaling in neuroendocrine and metabolic actions of leptin in male rats with uncontrolled diabetes. Endocrinology 2014; 155:4157-67. [PMID: 25137027 PMCID: PMC4197991 DOI: 10.1210/en.2014-1169] [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: 11/19/2022]
Abstract
Although the antidiabetic effects of leptin require intact neuronal melanocortin signaling in rodents with uncontrolled diabetes (uDM), increased melanocortin signaling is not sufficient to mimic leptin's glucose-lowering effects. The current studies were undertaken to clarify the role of melanocortin signaling in leptin's ability to correct metabolic and neuroendocrine disturbances associated with uDM. To accomplish this, bilateral cannulae were implanted in the lateral ventricle of rats with streptozotocin-induced diabetes, and leptin was coinfused with varying doses of the melanocortin 3/4 receptor (MC3/4R) antagonist, SHU9119. An additional cohort of streptozotocin-induced diabetes rats received intracerebroventricular administration of either the MC3/4R agonist, melanotan-II, or its vehicle. Consistent with previous findings, leptin's glucose-lowering effects were blocked by intracerebroventricular SHU9119. In contrast, leptin-mediated suppression of hyperglucagonemia involves both melanocortin dependent and independent mechanisms, and the degree of glucagon inhibition was associated with reduced plasma ketone body levels. Increased central nervous system melanocortin signaling alone fails to mimic leptin's ability to correct any of the metabolic or neuroendocrine disturbances associated with uDM. Moreover, the inability of increased melanocortin signaling to lower diabetic hyperglycemia does not appear to be secondary to release of the endogenous MC3/4R inverse agonist, Agouti-related peptide (AgRP), because AgRP knockout mice did not show increased susceptibility to the antidiabetic effects of increased MC3/4R signaling. Overall, these data suggest that 1) AgRP is not a major driver of diabetic hyperglycemia, 2) mechanisms independent of melanocortin signaling contribute to leptin's antidiabetic effects, and 3) melanocortin receptor blockade dissociates leptin's glucose-lowering effect from its action on other features of uDM, including reversal of hyperglucagonemia and ketosis, suggesting that brain control of ketosis, but not blood glucose levels, is glucagon dependent.
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Affiliation(s)
- Thomas H Meek
- Diabetes and Obesity Center of Excellence (T.H.M., M.E.M.,. V.D., A.C., G.J.M.), Department of Medicine, University of Washington, Seattle, Washington 98109; and Division of Endocrinology (S.C.C.), Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461
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Herwig A, Campbell G, Mayer CD, Boelen A, Anderson RA, Ross AW, Mercer JG, Barrett P. A thyroid hormone challenge in hypothyroid rats identifies T3 regulated genes in the hypothalamus and in models with altered energy balance and glucose homeostasis. Thyroid 2014; 24:1575-93. [PMID: 25087834 PMCID: PMC4229697 DOI: 10.1089/thy.2014.0169] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND The thyroid hormone triiodothyronine (T3) is known to affect energy balance. Recent evidence points to an action of T3 in the hypothalamus, a key area of the brain involved in energy homeostasis, but the components and mechanisms are far from understood. The aim of this study was to identify components in the hypothalamus that may be involved in the action of T3 on energy balance regulatory mechanisms. METHODS Sprague Dawley rats were made hypothyroid by giving 0.025% methimazole (MMI) in their drinking water for 22 days. On day 21, half the MMI-treated rats received a saline injection, whereas the others were injected with T3. Food intake and body weight measurements were taken daily. Body composition was determined by magnetic resonance imaging, gene expression was analyzed by in situ hybridization, and T3-induced gene expression was determined by microarray analysis of MMI-treated compared to MMI-T3-injected hypothalamic RNA. RESULTS Post mortem serum thyroid hormone levels showed that MMI treatment decreased circulating thyroid hormones and increased thyrotropin (TSH). MMI treatment decreased food intake and body weight. Body composition analysis revealed reduced lean and fat mass in thyroidectomized rats from day 14 of the experiment. MMI treatment caused a decrease in circulating triglyceride concentrations, an increase in nonesterified fatty acids, and decreased insulin levels. A glucose tolerance test showed impaired glucose clearance in the thyroidectomized animals. In the brain, in situ hybridization revealed marked changes in gene expression, including genes such as Mct8, a thyroid hormone transporter, and Agrp, a key component in energy balance regulation. Microarray analysis revealed 110 genes to be up- or downregulated with T3 treatment (± 1.3-fold change, p<0.05). Three genes chosen from the differentially expressed genes were verified by in situ hybridization to be activated by T3 in cells located at or close to the hypothalamic ventricular ependymal layer and differentially expressed in animal models of long- and short-term body weight regulation. CONCLUSION This study identified genes regulated by T3 in the hypothalamus, a key area of the brain involved in homeostasis and neuroendocrine functions. These include genes hitherto not known to be regulated by thyroid status.
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Affiliation(s)
- Annika Herwig
- Ingestive Behaviour Group, Rowett Institute for Nutrition and Health, University of Aberdeen, Aberdeen, United Kingdom
- Zoological Institute, University of Hamburg, Hamburg, Germany
| | - Gill Campbell
- Ingestive Behaviour Group, Rowett Institute for Nutrition and Health, University of Aberdeen, Aberdeen, United Kingdom
| | - Claus-Dieter Mayer
- Biomathematics and Statistics Scotland, Rowett Institute for Nutrition and Health, University of Aberdeen, Aberdeen, United Kingdom
| | - Anita Boelen
- Department of Endocrinology, Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Richard A. Anderson
- Ingestive Behaviour Group, Rowett Institute for Nutrition and Health, University of Aberdeen, Aberdeen, United Kingdom
| | - Alexander W. Ross
- Ingestive Behaviour Group, Rowett Institute for Nutrition and Health, University of Aberdeen, Aberdeen, United Kingdom
| | - Julian G. Mercer
- Ingestive Behaviour Group, Rowett Institute for Nutrition and Health, University of Aberdeen, Aberdeen, United Kingdom
| | - Perry Barrett
- Ingestive Behaviour Group, Rowett Institute for Nutrition and Health, University of Aberdeen, Aberdeen, United Kingdom
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