1
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Peng Y, Yao SY, Chen Q, Jin H, Du MQ, Xue YH, Liu S. True or false? Alzheimer's disease is type 3 diabetes: Evidences from bench to bedside. Ageing Res Rev 2024; 99:102383. [PMID: 38955264 DOI: 10.1016/j.arr.2024.102383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 06/12/2024] [Accepted: 06/17/2024] [Indexed: 07/04/2024]
Abstract
Globally, Alzheimer's disease (AD) is the most widespread chronic neurodegenerative disorder, leading to cognitive impairment, such as aphasia and agnosia, as well as mental symptoms, like behavioral abnormalities, that place a heavy psychological and financial burden on the families of the afflicted. Unfortunately, no particular medications exist to treat AD, as the current treatments only impede its progression.The link between AD and type 2 diabetes (T2D) has been increasingly revealed by research; the danger of developing both AD and T2D rises exponentially with age, with T2D being especially prone to AD. This has propelled researchers to investigate the mechanism(s) underlying this connection. A critical review of the relationship between insulin resistance, Aβ, oxidative stress, mitochondrial hypothesis, abnormal phosphorylation of Tau protein, inflammatory response, high blood glucose levels, neurotransmitters and signaling pathways, vascular issues in AD and diabetes, and the similarities between the two diseases, is presented in this review. Grasping the essential mechanisms behind this detrimental interaction may offer chances to devise successful therapeutic strategies.
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Affiliation(s)
- Yong Peng
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China; Department of Neurology, Affiliated Provincial Traditional Chinese Medical Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China.
| | - Shun-Yu Yao
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China; Department of Neurology, Affiliated Provincial Traditional Chinese Medical Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Quan Chen
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China; Department of Neurology, Affiliated Provincial Traditional Chinese Medical Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Hong Jin
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China; Department of Neurology, Affiliated Provincial Traditional Chinese Medical Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Miao-Qiao Du
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China; Department of Neurology, Affiliated Provincial Traditional Chinese Medical Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Ya-Hui Xue
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China; Department of Neurology, Affiliated Provincial Traditional Chinese Medical Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Shu Liu
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China; Department of Neurology, Affiliated Provincial Traditional Chinese Medical Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
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2
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Stangerup I, Kjeldsen SAS, Richter MM, Jensen NJ, Rungby J, Haugaard SB, Georg B, Hannibal J, Møllgård K, Wewer Albrechtsen NJ, Bjørnbak Holst C. Glucagon does not directly stimulate pituitary secretion of ACTH, GH or copeptin. Peptides 2024; 176:171213. [PMID: 38604379 DOI: 10.1016/j.peptides.2024.171213] [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: 12/28/2023] [Revised: 03/20/2024] [Accepted: 04/08/2024] [Indexed: 04/13/2024]
Abstract
Glucagon is best known for its contribution to glucose regulation through activation of the glucagon receptor (GCGR), primarily located in the liver. However, glucagon's impact on other organs may also contribute to its potent effects in health and disease. Given that glucagon-based medicine is entering the arena of anti-obesity drugs, elucidating extrahepatic actions of glucagon are of increased importance. It has been reported that glucagon may stimulate secretion of arginine-vasopressin (AVP)/copeptin, growth hormone (GH) and adrenocorticotrophic hormone (ACTH) from the pituitary gland. Nevertheless, the mechanisms and whether GCGR is present in human pituitary are unknown. In this study we found that intravenous administration of 0.2 mg glucagon to 14 healthy subjects was not associated with increases in plasma concentrations of copeptin, GH, ACTH or cortisol over a 120-min period. GCGR immunoreactivity was present in the anterior pituitary but not in cells containing GH or ACTH. Collectively, glucagon may not directly stimulate secretion of GH, ACTH or AVP/copeptin in humans but may instead be involved in yet unidentified pituitary functions.
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Affiliation(s)
- Ida Stangerup
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark; Department of Clinical Biochemistry, Copenhagen University Hospital - Nordsjælland, Hillerød, Denmark.
| | - Sasha A S Kjeldsen
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark; Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael M Richter
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark; Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicole J Jensen
- Steno Diabetes Center Copenhagen, Herlev, Denmark; Department of Endocrinology, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark
| | - Jørgen Rungby
- Steno Diabetes Center Copenhagen, Herlev, Denmark; Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Steen Bendix Haugaard
- Department of Endocrinology, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark; Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Birgitte Georg
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark
| | - Jens Hannibal
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark; Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kjeld Møllgård
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark; Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Camilla Bjørnbak Holst
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark; Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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3
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Xie C, Alkhouri N, Elfeki MA. Role of incretins and glucagon receptor agonists in metabolic dysfunction-associated steatotic liver disease: Opportunities and challenges. World J Hepatol 2024; 16:731-750. [PMID: 38818288 PMCID: PMC11135259 DOI: 10.4254/wjh.v16.i5.731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 02/18/2024] [Accepted: 04/03/2024] [Indexed: 05/22/2024] Open
Abstract
Metabolic dysfunction-associated steatotic liver disease (MASLD) has become the most common chronic liver disease worldwide, paralleling the rising pandemic of obesity and type 2 diabetes. Due to the growing global health burden and complex pathogenesis of MASLD, a multifaceted and innovative therapeutic approach is needed. Incretin receptor agonists, which were initially developed for diabetes management, have emerged as promising candidates for MASLD treatment. This review describes the pathophysiological mechanisms and action sites of three major classes of incretin/glucagon receptor agonists: glucagon-like peptide-1 receptor agonists, glucose-dependent insulinotropic polypeptide receptor agonists, and glucagon receptor agonists. Incretins and glucagon directly or indirectly impact various organs, including the liver, brain, pancreas, gastrointestinal tract, and adipose tissue. Thus, these agents significantly improve glycemic control and weight management and mitigate MASLD pathogenesis. Importantly, this study provides a summary of clinical trials analyzing the effectiveness and safety of incretin receptor agonists in MASLD management and provides an in-depth analysis highlighting their beneficial effects on improving liver function, hepatic steatosis, and intrahepatic inflammation. There are emerging challenges associated with the use of these medications in the real world, particularly adverse events, drug-drug interactions, and barriers to access, which are discussed in detail. Additionally, this review highlights the evolving role of incretin receptor agonists in MASLD management and suggests future research directions.
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Affiliation(s)
- Chencheng Xie
- Department of Internal Medicine, University of South Dakota Sanford School of Medicine, Sioux Falls, SD 57105, United States
- Department of Hepatology, Avera Mckennan University Hospital and Transplant Institute, Sioux Falls, SD 57105, United States
| | - Naim Alkhouri
- Department of Hepatology, Arizona Liver Health, Chandler, AZ 85712, United States
| | - Mohamed A Elfeki
- Department of Internal Medicine, University of South Dakota Sanford School of Medicine, Sioux Falls, SD 57105, United States
- Department of Hepatology, Avera McKennan University Hospital and Transplant Institute, Sioux Falls, SD 57105, United States.
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4
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Folli F, Finzi G, Manfrini R, Galli A, Casiraghi F, Centofanti L, Berra C, Fiorina P, Davalli A, La Rosa S, Perego C, Higgins PB. Mechanisms of action of incretin receptor based dual- and tri-agonists in pancreatic islets. Am J Physiol Endocrinol Metab 2023; 325:E595-E609. [PMID: 37729025 PMCID: PMC10874655 DOI: 10.1152/ajpendo.00236.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/15/2023] [Accepted: 09/16/2023] [Indexed: 09/22/2023]
Abstract
Simultaneous activation of the incretin G-protein-coupled receptors (GPCRs) via unimolecular dual-receptor agonists (UDRA) has emerged as a new therapeutic approach for type 2 diabetes. Recent studies also advocate triple agonism with molecules also capable of binding the glucagon receptor. In this scoping review, we discuss the cellular mechanisms of action (MOA) underlying the actions of these novel and therapeutically important classes of peptide receptor agonists. Clinical efficacy studies of several UDRAs have demonstrated favorable results both as monotherapies and when combined with approved hypoglycemics. Although the additive insulinotropic effects of dual glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic peptide receptor (GIPR) agonism were anticipated based on the known actions of either glucagon-like peptide-1 (GLP-1) or glucose-dependent insulinotropic peptide (GIP) alone, the additional benefits from GCGR were largely unexpected. Whether additional synergistic or antagonistic interactions among these G-protein receptor signaling pathways arise from simultaneous stimulation is not known. The signaling pathways affected by dual- and tri-agonism require more trenchant investigation before a comprehensive understanding of the cellular MOA. This knowledge will be essential for understanding the chronic efficacy and safety of these treatments.
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Affiliation(s)
- Franco Folli
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
- Unit of Diabetes, Endocrinology and Metabolism, San Paolo Hospital, ASST Santi Paolo e Carlo, Milan, Italy
| | - Giovanna Finzi
- Unit of Pathology, Department of Oncology, ASST Sette Laghi, Varese, Italy
| | - Roberto Manfrini
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
- Unit of Diabetes, Endocrinology and Metabolism, San Paolo Hospital, ASST Santi Paolo e Carlo, Milan, Italy
| | - Alessandra Galli
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Francesca Casiraghi
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
| | - Lucia Centofanti
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
| | - Cesare Berra
- IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
| | - Paolo Fiorina
- International Center for T1D, Pediatric Clinical Research Center Romeo ed Enrica Invernizzi, DIBIC, Università di Milano, Milan, Italy
- Nephrology Division, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
- Division of Endocrinology, ASST Fatebenefratelli-Sacco, Milan, Italy
| | - Alberto Davalli
- Diabetes and Endocrinology Unit, Department of Internal Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Stefano La Rosa
- Unit of Pathology, Department of Medicine and Technological Innovation, University of Insubria, Varese, Italy
| | - Carla Perego
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Paul B Higgins
- Department of Life & Physical Sciences, Atlantic Technological University, Letterkenny, Ireland
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5
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Sanetra AM, Palus-Chramiec K, Chrobok L, Jeczmien-Lazur JS, Klich JD, Lewandowski MH. Proglucagon signalling in the rat Dorsomedial Hypothalamus - Physiology and high-fat diet-mediated alterations. Mol Cell Neurosci 2023; 126:103873. [PMID: 37295578 DOI: 10.1016/j.mcn.2023.103873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/24/2023] [Accepted: 06/06/2023] [Indexed: 06/12/2023] Open
Abstract
A relatively new pharmacological target in obesity treatment has been the preproglucagon (PPG) signalling, predominantly with glucagon-like peptide (GLP) 1 receptor agonists. As far as the PPG role within the digestive system is well recognised, its actions in the brain remain understudied. Here, we investigated PPG signalling in the Dorsomedial Hypothalamus (DMH), a structure involved in feeding regulation and metabolism, using in situ hybridisation, electrophysiology, and immunohistochemistry. Our experiments were performed on animals fed both control, and high-fat diet (HFD), uncovering HFD-mediated alterations. First, sensitivity to exendin-4 (Exn4, a GLP1R agonist) was shown to increase under HFD, with a higher number of responsive neurons. The amplitude of the response to both Exn4 and oxyntomodulin (Oxm) was also altered, diminishing its relationship with the cells' spontaneous firing rate. Not only neuronal sensitivity, but also GLP1 presence, and therefore possibly release, was influenced by HFD. Immunofluorescent labelling of the GLP1 showed changes in its density depending on the metabolic state (fasted/fed), but this effect was eliminated by HFD feeding. Interestingly, these dietary differences were absent after a period of restricted feeding, allowing for an anticipation of the alternating metabolic states, which suggests possible prevention of such outcome.
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Affiliation(s)
- A M Sanetra
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, 30-387 Krakow, Poland.
| | - K Palus-Chramiec
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, 30-387 Krakow, Poland
| | - L Chrobok
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, 30-387 Krakow, Poland; School of Physiology, Pharmacology, and Neuroscience, University of Bristol, University Walk, Biomedical Sciences Building, Bristol BS8 1TD, UK
| | - J S Jeczmien-Lazur
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, 30-387 Krakow, Poland
| | - J D Klich
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, 30-387 Krakow, Poland; Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle Street 10, 13125 Berlin, Germany
| | - M H Lewandowski
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa Street 9, 30-387 Krakow, Poland.
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6
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Edgerton DS, Kraft G, Smith M, Farmer B, Williams P, Cherrington AD. A physiologic increase in brain glucagon action alters the hepatic gluconeogenic/glycogenolytic ratio but not glucagon's overall effect on glucose production. Am J Physiol Endocrinol Metab 2023; 324:E199-E208. [PMID: 36652399 PMCID: PMC9925168 DOI: 10.1152/ajpendo.00304.2022] [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: 11/16/2022] [Revised: 01/12/2023] [Accepted: 01/12/2023] [Indexed: 01/19/2023]
Abstract
It has been proposed that brain glucagon action inhibits glucagon-stimulated hepatic glucose production (HGP), which may explain, at least in part, why glucagon's effect on HGP is transient. However, the pharmacologic off-target effects of glucagon in the brain may have been responsible for previously observed effects. Therefore, the aim of this study was to determine if central glucagon action plays a physiologic role in the regulation of HGP. Insulin was maintained at baseline while glucagon was either infused into the carotid and vertebral arteries or into a peripheral (leg) vein at rates designed to increase glucagon in the head in one group, while keeping glucagon at the liver matched between groups. The extraction rate of glucagon across the head was high (double that of the liver), and hypothalamic cAMP increased twofold, in proportion to the exposure of the brain to increased glucagon, but HGP was not reduced by the increase in brain glucagon signaling, as had been suggested previously (the areas under the curve for HGP were 840 ± 14 vs. 871 ± 36 mg/kg/240 min in head vs. peripheral infusion groups, respectively). Central nervous system glucagon action reduced circulating free fatty acids and glycerol, and this was associated with a modest reduction in net hepatic gluconeogenic flux. However, offsetting autoregulation by the liver (i.e., a reciprocal increase in net hepatic glycogenolysis) prevented a change in HGP. Thus, while physiologic engagement of the brain by glucagon can alter hepatic carbon flux, it does not appear to be responsible for the transient fall in HGP that occurs following the stimulation of HGP during a square wave rise in glucagon.NEW & NOTEWORTHY Glucagon stimulates hepatic glucose production through its direct effects on the liver but may indirectly inhibit this process by acting on the brain. This was tested by delivering glucagon via the cerebral circulatory system. Central nervous system glucagon action reduced liver gluconeogenic flux, but glycogenolysis increased, resulting in no net change in hepatic glucose production. Surprisingly, brain glucagon also appeared to suppress lipolysis (plasma free fatty acid and glycerol levels were reduced).
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Affiliation(s)
- Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Guillaume Kraft
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Marta Smith
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Ben Farmer
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Phillip Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
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7
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Bomholt AB, Johansen CD, Christensen JB, Kjeldsen SAS, Galsgaard KD, Winther-Sørensen M, Serizawa R, Hornum M, Porrini E, Pedersen J, Ørskov C, Gluud LL, Sørensen CM, Holst JJ, Albrechtsen R, Wewer Albrechtsen NJ. Evaluation of commercially available glucagon receptor antibodies and glucagon receptor expression. Commun Biol 2022; 5:1278. [PMID: 36418521 PMCID: PMC9684523 DOI: 10.1038/s42003-022-04242-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 11/09/2022] [Indexed: 11/24/2022] Open
Abstract
Glucagon is a major regulator of metabolism and drugs targeting the glucagon receptor (GCGR) are being developed. Insight into tissue and cell-specific expression of the GCGR is important to understand the biology of glucagon and to differentiate between direct and indirect actions of glucagon. However, it has been challenging to localize the GCGR in tissue due to low expression levels and lack of specific methods. Immunohistochemistry has frequently been used for GCGR localization, but antibodies targeting G-protein-coupled-receptors may be inaccurate. We evaluated all currently commercially available GCGR antibodies. The antibody, ab75240 (Antibody no. 11) was found to perform best among the twelve antibodies tested and using this antibody we found expression of the GCGR in the kidney, liver, preadipocytes, pancreas, and heart. Three antibody-independent approaches all confirmed the presence of the GCGR within the pancreas, liver and the kidneys. GCGR expression should be evaluated by both antibody and antibody-independent approaches.
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Affiliation(s)
- Anna Billeschou Bomholt
- grid.5254.60000 0001 0674 042XDepartment of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christian Dall Johansen
- grid.5254.60000 0001 0674 042XDepartment of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark ,grid.5254.60000 0001 0674 042XNovo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bager Christensen
- grid.5254.60000 0001 0674 042XDepartment of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sasha Alexandra Sampson Kjeldsen
- grid.5254.60000 0001 0674 042XDepartment of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark ,grid.5254.60000 0001 0674 042XNovo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Katrine Douglas Galsgaard
- grid.5254.60000 0001 0674 042XDepartment of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark ,grid.5254.60000 0001 0674 042XNovo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marie Winther-Sørensen
- grid.5254.60000 0001 0674 042XDepartment of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark ,grid.5254.60000 0001 0674 042XNovo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Reza Serizawa
- grid.4973.90000 0004 0646 7373Department of Pathology, Copenhagen University Hospital, Hvidovre, Denmark
| | - Mads Hornum
- grid.475435.4Department of Nephrology, Centre for Cancer and Organ Diseases, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark ,grid.5254.60000 0001 0674 042XDepartment of Clinical Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Esteban Porrini
- grid.411220.40000 0000 9826 9219Instituto de Tecnologías Biomédicas, University of La Laguna, Research Unit, Hospital Universitario de Canarias, Tenerife, Spain
| | - Jens Pedersen
- grid.5254.60000 0001 0674 042XDepartment of Clinical Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark ,grid.411900.d0000 0004 0646 8325Department of Internal Medicine, Endocrinology, Copenhagen University Hospital Herlev, Herlev, Denmark
| | - Cathrine Ørskov
- grid.5254.60000 0001 0674 042XDepartment of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lise Lotte Gluud
- grid.5254.60000 0001 0674 042XDepartment of Clinical Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark ,grid.4973.90000 0004 0646 7373Gastro Unit, Copenhagen University Hospital, Hvidovre, Denmark
| | - Charlotte Mehlin Sørensen
- grid.5254.60000 0001 0674 042XDepartment of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Juul Holst
- grid.5254.60000 0001 0674 042XDepartment of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark ,grid.5254.60000 0001 0674 042XNovo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Reidar Albrechtsen
- grid.5254.60000 0001 0674 042XBiotech Research & Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai Jacob Wewer Albrechtsen
- grid.5254.60000 0001 0674 042XDepartment of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark ,grid.5254.60000 0001 0674 042XNovo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark ,grid.512917.9Department of Clinical Biochemistry, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark
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8
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Regulation of feeding and therapeutic application of bioactive peptides. Pharmacol Ther 2022; 239:108187. [DOI: 10.1016/j.pharmthera.2022.108187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/25/2022] [Accepted: 04/07/2022] [Indexed: 10/18/2022]
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9
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Insights into the Role of Glucagon Receptor Signaling in Metabolic Regulation from Pharmacological Inhibition and Tissue-Specific Knockout Models. Biomedicines 2022; 10:biomedicines10081907. [PMID: 36009454 PMCID: PMC9405517 DOI: 10.3390/biomedicines10081907] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/01/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
Abstract
While glucagon has long been recognized as the primary counter hormone to insulin’s actions, it has recently gained recognition as a metabolic regulator with its effects extending beyond control of glycemia. Recently developed models of tissue-specific glucagon receptor knockouts have advanced our understanding of this hormone, providing novel insight into the role it plays within organs as well as its systemic effects. Studies where the pharmacological blockade of the glucagon receptor has been employed have proved similarly valuable in the study of organ-specific and systemic roles of glucagon signaling. Studies carried out employing these tools demonstrate that glucagon indeed plays a role in regulating glycemia, but also in amino acid and lipid metabolism, systemic endocrine, and paracrine function, and in the response to cardiovascular injury. Here, we briefly review recent progress in our understanding of glucagon’s role made through inhibition of glucagon receptor signaling utilizing glucagon receptor antagonists and tissue specific genetic knockout models.
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10
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Wendt A, Eliasson L. Pancreatic alpha cells and glucagon secretion: Novel functions and targets in glucose homeostasis. Curr Opin Pharmacol 2022; 63:102199. [PMID: 35245797 DOI: 10.1016/j.coph.2022.102199] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 01/25/2022] [Accepted: 01/31/2022] [Indexed: 11/16/2022]
Abstract
Diabetes is the result of dysregulation of both insulin and glucagon. Still, insulin has attracted much more attention than glucagon. Glucagon is released from alpha cells in the islets of Langerhans in response to low glucose and certain amino acids. Drugs with the primary aim of targeting glucagon signalling are scarce. However, glucagon is often administered to counteract severe hypoglycaemia, and commonly used diabetes medications such as GLP-1 analogues, sulfonylureas and SGLT2-inhibitors also affect alpha cells. Indeed, there are physiological and developmental similarities between the alpha cell and the insulin-secreting beta cell and new data confirm that alpha cells can be converted into insulin-secreting cells. These aspects and attributes, the need to find novel therapies targeting the alpha cell and more are considered in this review.
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Affiliation(s)
- Anna Wendt
- Islet Cell Exocytosis, Lund University Diabetes Centre, Department of Clinical Sciences Malmö, Lund University, Clinical Research Centre, SUS, Malmö, Sweden
| | - Lena Eliasson
- Islet Cell Exocytosis, Lund University Diabetes Centre, Department of Clinical Sciences Malmö, Lund University, Clinical Research Centre, SUS, Malmö, Sweden.
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11
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Martins-Oliveira M, Tavares I, Goadsby PJ. Was it something I ate? Understanding the bidirectional interaction of migraine and appetite neural circuits. Brain Res 2021; 1770:147629. [PMID: 34428465 DOI: 10.1016/j.brainres.2021.147629] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 12/18/2022]
Abstract
Migraine attacks can involve changes of appetite: while fasting or skipping meals are often reported triggers in susceptible individuals, hunger or food craving are reported in the premonitory phase. Over the last decade, there has been a growing interest and recognition of the importance of studying these overlapping fields of neuroscience, which has led to novel findings. The data suggest additional studies are needed to unravel key neurobiological mechanisms underlying the bidirectional interaction between migraine and appetite. Herein, we review information about the metabolic migraine phenotype and explore migraine therapeutic targets that have a strong input on appetite neuronal circuits, including the calcitonin gene-related peptide (CGRP), the pituitary adenylate cyclase-activating polypeptide (PACAP) and the orexins. Furthermore, we focus on potential therapeutic peptide targets that are involved in regulation of feeding and play a role in migraine pathophysiology, such as neuropeptide Y, insulin, glucagon and leptin. We then examine the orexigenic - anorexigenic circuit feedback loop and explore glucose metabolism disturbances. Additionally, it is proposed a different perspective on the most reported feeding-related trigger - skipping meals - as well as a link between contrasting feeding behaviors (skipping meals vs food craving). Our review aims to increase awareness of migraine through the lens of appetite neurobiology in order to improve our understanding of the earlier phase of migraine, encourage better studies and cross-disciplinary collaborations, and provide novel migraine-specific therapeutic opportunities.
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Affiliation(s)
- Margarida Martins-Oliveira
- Headache Group, Wolfson Centre for Age-Related Disease, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK; Nutrition and Metabolism Department, NOVA Medical School, Faculdade de Ciências Médicas de Lisboa, Universidade Nova de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisbon, Portugal.
| | - Isaura Tavares
- Department of Biomedicine, Unit of Experimental Biology, Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; Institute of Investigation and Innovation in Health (i3S), University of Porto, Portugal.
| | - Peter J Goadsby
- Headache Group, Wolfson Centre for Age-Related Disease, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK; Department of Neurology, University of California, Los Angeles, Los Angeles, CA, USA.
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12
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Zeigerer A, Sekar R, Kleinert M, Nason S, Habegger KM, Müller TD. Glucagon's Metabolic Action in Health and Disease. Compr Physiol 2021; 11:1759-1783. [PMID: 33792899 PMCID: PMC8513137 DOI: 10.1002/cphy.c200013] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Discovered almost simultaneously with insulin, glucagon is a pleiotropic hormone with metabolic action that goes far beyond its classical role to increase blood glucose. Albeit best known for its ability to directly act on the liver to increase de novo glucose production and to inhibit glycogen breakdown, glucagon lowers body weight by decreasing food intake and by increasing metabolic rate. Glucagon further promotes lipolysis and lipid oxidation and has positive chronotropic and inotropic effects in the heart. Interestingly, recent decades have witnessed a remarkable renaissance of glucagon's biology with the acknowledgment that glucagon has pharmacological value beyond its classical use as rescue medication to treat severe hypoglycemia. In this article, we summarize the multifaceted nature of glucagon with a special focus on its hepatic action and discuss the pharmacological potential of either agonizing or antagonizing the glucagon receptor for health and disease. © 2021 American Physiological Society. Compr Physiol 11:1759-1783, 2021.
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Affiliation(s)
- Anja Zeigerer
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Revathi Sekar
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Maximilian Kleinert
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Shelly Nason
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Kirk M. Habegger
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Timo D. Müller
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany
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13
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Dybjer E, Engström G, Helmer C, Nägga K, Rorsman P, Nilsson PM. Incretin hormones, insulin, glucagon and advanced glycation end products in relation to cognitive function in older people with and without diabetes, a population-based study. Diabet Med 2020; 37:1157-1166. [PMID: 32020688 DOI: 10.1111/dme.14267] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/03/2020] [Indexed: 12/23/2022]
Abstract
AIM The aim of this observational study was to investigate relationships between physiological levels of glucometabolic biomarkers and cognitive test results in a population-based setting. METHODS Cross-sectional data were obtained from the Swedish population-based Malmö Diet and Cancer Study Re-examination 2007-2012 comprising 3001 older people (mean age 72 years). Through oral glucose tolerance testing (OGTT), fasting and post-load levels of serum insulin, plasma glucagon, serum glucose-dependent insulinotropic peptide (GIP) and plasma glucagon-like peptide-1 (GLP-1) were measured. Insulin resistance and insulin sensitivity levels were calculated. In 454 participants, advanced glycation end products (AGEs) were estimated through skin autofluorescence. Associations between biomarkers and two cognitive tests, the Mini-Mental State Examination (MMSE) and A Quick Test of Cognitive Speed (AQT) respectively, were explored in multiple regression analyses. RESULTS Positive associations following adjustments for known prognostic factors were found between MMSE scores and insulin sensitivity (B = 0.822, P = 0.004), 2-h plasma glucagon (B = 0.596, P = 0.026), 2-h serum GIP (B = 0.581, P = 0.040) and 2-h plasma GLP-1 (B = 0.585, P = 0.038), whereas negative associations were found between MMSE scores and insulin resistance (B = -0.734, P = 0.006), fasting plasma GLP-1 (B = -0.544, P = 0.033) and AGEs (B = -1.459, P = 0.030) were found. CONCLUSIONS Higher levels of insulin sensitivity, GIP and GLP-1 were associated with better cognitive outcomes, but AGEs were associated with worse outcomes, supporting evidence from preclinical studies. Glucagon was linked to better outcomes, which could possibly reflect neuroprotective properties similar to the related biomarker GLP-1 which has similar intracellular properties. Longitudinal and interventional studies are needed to further evaluate neuromodulating effects of these biomarkers. Abstract presented at the European Association for the Study of Diabetes (EASD) 2019, Barcelona, Spain.
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Affiliation(s)
- E Dybjer
- Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - G Engström
- Department of Clinical Sciences, Lund University, Malmö, Sweden
| | - C Helmer
- University of Bordeaux, INSERM, Bordeaux Population Health Research Center, UMR 1219, Bordeaux, France
| | - K Nägga
- Department of Clinical Sciences, Lund University, Malmö, Sweden
- Department of Acute Internal Medicine and Geriatrics, Linköping University, Linköping, Sweden
| | - P Rorsman
- Metabolic Research, Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - P M Nilsson
- Department of Clinical Sciences, Lund University, Malmö, Sweden
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14
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A GLP-1/GIP/Gcg receptor triagonist improves memory behavior, as well as synaptic transmission, neuronal excitability and Ca2+ homeostasis in 3xTg-AD mice. Neuropharmacology 2020; 170:108042. [DOI: 10.1016/j.neuropharm.2020.108042] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 02/13/2020] [Accepted: 03/04/2020] [Indexed: 12/20/2022]
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15
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Stemmer K, Finan B, DiMarchi RD, Tschöp MH, Müller TD. Insights into incretin-based therapies for treatment of diabetic dyslipidemia. Adv Drug Deliv Rev 2020; 159:34-53. [PMID: 32485206 DOI: 10.1016/j.addr.2020.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/09/2020] [Accepted: 05/23/2020] [Indexed: 02/07/2023]
Abstract
Derangements in triglyceride and cholesterol metabolism (dyslipidemia) are major risk factors for the development of cardiovascular diseases in obese and type-2 diabetic (T2D) patients. An emerging class of glucagon-like peptide-1 (GLP-1) analogues and next generation peptide dual-agonists such as GLP-1/glucagon or GLP-1/GIP could provide effective therapeutic options for T2D patients. In addition to their role in glucose and energy homeostasis, GLP-1, GIP and glucagon serve as regulators of lipid metabolism. This review summarizes the current knowledge in GLP-1, glucagon and GIP effects on lipid and lipoprotein metabolism and frames the emerging therapeutic benefits of GLP-1 analogs and GLP-1-based multiagonists as add-on treatment options for diabetes associated dyslipidemia.
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16
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Zhang C, Lian A, Xu Y, Jiang Q. Signal Transduction Mechanisms for Glucagon-Induced Somatolactin Secretion and Gene Expression in Nile Tilapia ( Oreochromis niloticus) Pituitary Cells. Front Endocrinol (Lausanne) 2020; 11:629077. [PMID: 33613457 PMCID: PMC7890253 DOI: 10.3389/fendo.2020.629077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 12/23/2020] [Indexed: 11/13/2022] Open
Abstract
Glucagon (GCG) plays a stimulatory role in pituitary hormone regulation, although previous studies have not defined the molecular mechanism whereby GCG affects pituitary hormone secretion. To this end, we identified two distinct proglucagons, Gcga and Gcgb, as well as GCG receptors, Gcgra and Gcgrb, in Nile tilapia (Oreochromis niloticus). Using the cAMP response element (CRE)-luciferase reporter system, tilapia GCGa and GCGb could reciprocally activate the two GCG receptors expressed in human embryonic kidney 293 (HEK293) cells. Quantitative real-time PCR analysis revealed that differential expression of the Gcga and Gcgb and their cognate receptors Gcgra and Gcgrb was found in the various tissues of tilapia. In particular, the Gcgrb is abundantly expressed in the neurointermediate lobe (NIL) of the pituitary gland. In primary cultures of tilapia NIL cells, GCGb effectively stimulated SL release, with parallel rises in the mRNA levels, and co-incubation with the GCG antagonist prevented GCGb-stimulated SL release. In parallel experiments, GCGb treatment dose-dependently enhanced intracellular cyclic adenosine monophosphate (cAMP) accumulation with increasing inositol 1,4,5-trisphosphate (IP3) concentration and the resulting in transient increases of Ca2+ signals in the primary NIL cell culture. Using selective pharmacological approaches, the adenylyl cyclase (AC)/cAMP/protein kinase A (PKA) and phospholipase C (PLC)/IP3/Ca2+/calmodulin (CaM)/CaMK-II pathways were shown to be involved in GCGb-induced SL release and mRNA expression. Together, these results provide evidence for the first time that GCGb can act at the pituitary level to stimulate SL release and gene expression via GCGRb through the activation of the AC/cAMP/PKA and PLC/IP3/Ca2+/CaM/CaMK-II cascades.
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17
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Li Y, Glotfelty EJ, Namdar I, Tweedie D, Olson L, Hoffer BJ, DiMarchi RD, Pick CG, Greig NH. Neurotrophic and neuroprotective effects of a monomeric GLP-1/GIP/Gcg receptor triagonist in cellular and rodent models of mild traumatic brain injury. Exp Neurol 2019; 324:113113. [PMID: 31730763 DOI: 10.1016/j.expneurol.2019.113113] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 02/08/2023]
Abstract
A synthetic monomeric peptide triple receptor agonist, termed "Triagonist" that incorporates glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and glucagon (Gcg) actions, was previously developed to improve upon metabolic and glucose regulatory benefits of single and dual receptor agonists in rodent models of diet-induced obesity and type 2 diabetes. In the current study, the neurotrophic and neuroprotective actions of this Triagonist were probed in cellular and mouse models of mild traumatic brain injury (mTBI), a prevalent cause of neurodegeneration in both the young and elderly. Triagonist dose- and time-dependently elevated cyclic AMP levels in cultured human SH-SY5Y neuronal cells, and induced neurotrophic and neuroprotective actions, mitigating oxidative stress and glutamate excitotoxicity. These actions were inhibited only by the co-administration of antagonists for all three receptor types, indicating the balanced co-involvement of GLP-1, GIP and Gcg receptors. To evaluate physiological relevance, a clinically translatable dose of Triagonist was administered subcutaneously, once daily for 7 days, to mice following a 30 g weight drop close head injury. Triagonist fully mitigated mTBI-induced visual and spatial memory deficits, evaluated at 7 and 30 days post injury. These results establish Triagonist as a novel neurotrophic/protective agent worthy of further evaluation as a TBI treatment strategy.
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Affiliation(s)
- Yazhou Li
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
| | - Elliot J Glotfelty
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Inbar Namdar
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - David Tweedie
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Lars Olson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Barry J Hoffer
- Department of Neurosurgery, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | | | - Chagi G Pick
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Nigel H Greig
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
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18
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Kleinert M, Sachs S, Habegger KM, Hofmann SM, Müller TD. Glucagon Regulation of Energy Expenditure. Int J Mol Sci 2019; 20:ijms20215407. [PMID: 31671603 PMCID: PMC6862306 DOI: 10.3390/ijms20215407] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 02/07/2023] Open
Abstract
Glucagon's ability to increase energy expenditure has been known for more than 60 years, yet the mechanisms underlining glucagon's thermogenic effect still remain largely elusive. Over the last years, significant efforts were directed to unravel the physiological and cellular underpinnings of how glucagon regulates energy expenditure. In this review, we summarize the current knowledge on how glucagon regulates systems metabolism with a special emphasis on its acute and chronic thermogenic effects.
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Affiliation(s)
- Maximilian Kleinert
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Centre Munich, Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany.
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, 2100 Copenhagen, Denmark.
| | - Stephan Sachs
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Centre Munich, Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany.
- Division of Metabolic Diseases, Technische Universität München, 85740 Munich, Germany.
| | - Kirk M Habegger
- Department of Medicine-Endocrinology and Comprehensive Diabetes Center, Diabetes and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35899, USA.
| | - Susanna M Hofmann
- Institute for Diabetes and Regeneration, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany.
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.
- Medizinische Klinik und Poliklinik IV, Klinikum der LMU, 80336 München, Germany.
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Centre Munich, Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany.
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, 72076 Tübingen, Germany.
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19
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Glucagon Control on Food Intake and Energy Balance. Int J Mol Sci 2019; 20:ijms20163905. [PMID: 31405212 PMCID: PMC6719123 DOI: 10.3390/ijms20163905] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 07/24/2019] [Accepted: 08/08/2019] [Indexed: 12/17/2022] Open
Abstract
Glucagon exerts pleiotropic actions on energy balance and has emerged as an attractive target for the treatment of diabetes and obesity in the last few years. Glucagon reduces body weight and adiposity by suppression of appetite and by modulation of lipid metabolism. Moreover, this hormone promotes weight loss by activation of energy expenditure and thermogenesis. In this review, we cover these metabolic actions elicited by glucagon beyond its canonical regulation of glucose metabolism. In addition, we discuss recent developments of therapeutic approaches in the treatment of obesity and diabetes by dual- and tri-agonist molecules based on combinations of glucagon with other peptides. New strategies using these unimolecular polyagonists targeting the glucagon receptor (GCGR), have become successful approaches to evaluate the multifaceted nature of glucagon signaling in energy balance and metabolic syndrome.
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20
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Koorneef LL, Bogaards M, Reinders MJT, Meijer OC, Mahfouz A. How Metabolic State May Regulate Fear: Presence of Metabolic Receptors in the Fear Circuitry. Front Neurosci 2018; 12:594. [PMID: 30210279 PMCID: PMC6119828 DOI: 10.3389/fnins.2018.00594] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 08/07/2018] [Indexed: 12/13/2022] Open
Abstract
Metabolic status impacts on the emotional brain to induce behavior that maintains energy balance. While hunger suppresses the fear circuitry to promote explorative food-seeking behavior, satiety or obesity may increase fear to prevent unnecessary risk-taking. Here we aimed to unravel which metabolic factors, that transfer information about the acute and the chronic metabolic status, are of primary importance to regulate fear, and to identify their sites of action within fear-related brain regions. We performed a de novo analysis of central and peripheral metabolic factors that can penetrate the blood–brain barrier using genome-wide expression data across the mouse brain from the Allen Brain Atlas (ABA). The central fear circuitry, as defined by subnuclei of the amygdala, the afferent hippocampus, the medial prefrontal cortex and the efferent periaqueductal gray, was enriched with metabolic receptors. Some of their corresponding ligands were known to modulate fear (e.g., estrogen and thyroid hormones) while others had not been associated with fear before (e.g., glucagon, ACTH). Additionally, several of these enriched metabolic receptors were coexpressed with well-described fear-modulating genes (Crh, Crhr1, or Crhr2). Co-expression analysis of monoamine markers and metabolic receptors suggested that monoaminergic nuclei have differential sensitivity to metabolic alterations. Serotonergic neurons expressed a large number of metabolic receptors (e.g., estrogen receptors, fatty acid receptors), suggesting a wide responsivity to metabolic changes. The noradrenergic system seemed to be specifically sensitive to hypocretin/orexin modulation. Taken together, we identified a number of novel metabolic factors (glucagon, ACTH) that have the potential to modulate the fear response. We additionally propose novel cerebral targets for metabolic factors (e.g., thyroid hormones) that modulate fear, but of which the sites of action are (largely) unknown.
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Affiliation(s)
- Lisa L Koorneef
- Division of Endocrinology, Department of Internal Medicine, Leiden University Medical Center, Leiden University, Leiden, Netherlands.,Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden University, Leiden, Netherlands
| | - Marit Bogaards
- Division of Endocrinology, Department of Internal Medicine, Leiden University Medical Center, Leiden University, Leiden, Netherlands.,Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden University, Leiden, Netherlands
| | - Marcel J T Reinders
- Leiden Computational Biology Center, Leiden University Medical Center, Leiden University, Leiden, Netherlands.,Delft Bioinformatics Laboratory, Delft University of Technology, Delft, Netherlands
| | - Onno C Meijer
- Division of Endocrinology, Department of Internal Medicine, Leiden University Medical Center, Leiden University, Leiden, Netherlands.,Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden University, Leiden, Netherlands.,Leiden Institute for Brain and Cognition, Leiden University Medical Center, Leiden University, Leiden, Netherlands
| | - Ahmed Mahfouz
- Leiden Computational Biology Center, Leiden University Medical Center, Leiden University, Leiden, Netherlands.,Delft Bioinformatics Laboratory, Delft University of Technology, Delft, Netherlands
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21
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Neuroprotective effects of a triple GLP-1/GIP/glucagon receptor agonist in the APP/PS1 transgenic mouse model of Alzheimer's disease. Brain Res 2018; 1678:64-74. [DOI: 10.1016/j.brainres.2017.10.012] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 10/07/2017] [Accepted: 10/11/2017] [Indexed: 12/13/2022]
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22
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Müller TD, Finan B, Clemmensen C, DiMarchi RD, Tschöp MH. The New Biology and Pharmacology of Glucagon. Physiol Rev 2017; 97:721-766. [PMID: 28275047 DOI: 10.1152/physrev.00025.2016] [Citation(s) in RCA: 206] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In the last two decades we have witnessed sizable progress in defining the role of gastrointestinal signals in the control of glucose and energy homeostasis. Specifically, the molecular basis of the huge metabolic benefits in bariatric surgery is emerging while novel incretin-based medicines based on endogenous hormones such as glucagon-like peptide 1 and pancreas-derived amylin are improving diabetes management. These and related developments have fostered the discovery of novel insights into endocrine control of systemic metabolism, and in particular a deeper understanding of the importance of communication across vital organs, and specifically the gut-brain-pancreas-liver network. Paradoxically, the pancreatic peptide glucagon has reemerged in this period among a plethora of newly identified metabolic macromolecules, and new data complement and challenge its historical position as a gut hormone involved in metabolic control. The synthesis of glucagon analogs that are biophysically stable and soluble in aqueous solutions has promoted biological study that has enriched our understanding of glucagon biology and ironically recruited glucagon agonism as a central element to lower body weight in the treatment of metabolic disease. This review summarizes the extensive historical record and the more recent provocative direction that integrates the prominent role of glucagon in glucose elevation with its under-acknowledged effects on lipids, body weight, and vascular health that have implications for the pathophysiology of metabolic diseases, and the emergence of precision medicines to treat metabolic diseases.
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Affiliation(s)
- T D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - B Finan
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - C Clemmensen
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - R D DiMarchi
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - M H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
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23
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Sekar R, Wang L, Chow BKC. Central Control of Feeding Behavior by the Secretin, PACAP, and Glucagon Family of Peptides. Front Endocrinol (Lausanne) 2017; 8:18. [PMID: 28223965 PMCID: PMC5293785 DOI: 10.3389/fendo.2017.00018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/18/2017] [Indexed: 12/25/2022] Open
Abstract
Constituting a group of structurally related brain-gut peptides, secretin (SCT), pituitary adenylate cyclase-activating peptide (PACAP), and glucagon (GCG) family of peptide hormones exert their functions via interactions with the class B1 G protein-coupled receptors. In recent years, the roles of these peptides in neuroendocrine control of feeding behavior have been a specific area of research focus for development of potential therapeutic drug targets to combat obesity and metabolic disorders. As a result, some members in the family and their analogs have already been utilized as therapeutic agents in clinical application. This review aims to provide an overview of the current understanding on the important role of SCT, PACAP, and GCG family of peptides in central control of feeding behavior.
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Affiliation(s)
- Revathi Sekar
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Lei Wang
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
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24
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Yip J, Geng X, Shen J, Ding Y. Cerebral Gluconeogenesis and Diseases. Front Pharmacol 2017; 7:521. [PMID: 28101056 PMCID: PMC5209353 DOI: 10.3389/fphar.2016.00521] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 12/15/2016] [Indexed: 01/08/2023] Open
Abstract
The gluconeogenesis pathway, which has been known to normally present in the liver, kidney, intestine, or muscle, has four irreversible steps catalyzed by the enzymes: pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase, and glucose 6-phosphatase. Studies have also demonstrated evidence that gluconeogenesis exists in brain astrocytes but no convincing data have yet been found in neurons. Astrocytes exhibit significant 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 activity, a key mechanism for regulating glycolysis and gluconeogenesis. Astrocytes are unique in that they use glycolysis to produce lactate, which is then shuttled into neurons and used as gluconeogenic precursors for reduction. This gluconeogenesis pathway found in astrocytes is becoming more recognized as an important alternative glucose source for neurons, specifically in ischemic stroke and brain tumor. Further studies are needed to discover how the gluconeogenesis pathway is controlled in the brain, which may lead to the development of therapeutic targets to control energy levels and cellular survival in ischemic stroke patients, or inhibit gluconeogenesis in brain tumors to promote malignant cell death and tumor regression. While there are extensive studies on the mechanisms of cerebral glycolysis in ischemic stroke and brain tumors, studies on cerebral gluconeogenesis are limited. Here, we review studies done to date regarding gluconeogenesis to evaluate whether this metabolic pathway is beneficial or detrimental to the brain under these pathological conditions.
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Affiliation(s)
- James Yip
- Department of Neurosurgery, Wayne State University School of Medicine Detroit, MI, USA
| | - Xiaokun Geng
- Department of Neurosurgery, Wayne State University School of MedicineDetroit, MI, USA; China-America Institute of Neuroscience, Beijing Luhe Hospital, Capital Medical UniversityBeijing, China; Department of Neurology, Beijing Luhe Hospital, Capital Medical UniversityBeijing, China
| | - Jiamei Shen
- Department of Neurosurgery, Wayne State University School of MedicineDetroit, MI, USA; China-America Institute of Neuroscience, Beijing Luhe Hospital, Capital Medical UniversityBeijing, China
| | - Yuchuan Ding
- Department of Neurosurgery, Wayne State University School of MedicineDetroit, MI, USA; China-America Institute of Neuroscience, Beijing Luhe Hospital, Capital Medical UniversityBeijing, China
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Molina-Villa T, Mendoza V, López-Casillas F. Affinity Labeling Detection of Endogenous Receptors from Zebrafish Embryos. J Vis Exp 2016. [PMID: 27685504 DOI: 10.3791/54405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
By combining the powers of Affinity Labeling and Immunoprecipitation (AFLIP), a technique for the detection of low abundance receptors in zebrafish embryos has been implemented. This technique takes advantage of the selectivity and sensitivity conferred by affinity labeling of a given receptor by its ligand with the specificity of the immunoprecipitation. We have used AFLIP to detect the type III TGF-β receptor (TGFBR3), also know as betaglycan, during early zebrafish development. AFLIP was instrumental in validating the efficacy of a TGFBR3 morphant zebrafish phenotype. In the first step, embryo protein extracts are prepared and used to generate 125I-TGF-β2-TGFBR3 complexes that are purified by immunoprecipitation. Later, these complexes are covalently cross-linked and revealed using SDS-PAGE separation and autoradiography detection. This technique requires the availability of a labeled ligand for, and a specific antibody against, the receptor to be detected, and shall be easily adapted to identify any growth factor or cytokine receptor that meets these requirements.
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Affiliation(s)
- Tonatiuh Molina-Villa
- Cell and Developmental Biology, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México
| | - Valentín Mendoza
- Cell and Developmental Biology, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México
| | - Fernando López-Casillas
- Cell and Developmental Biology, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México;
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Abstract
In recent years, novel discoveries have reshaped our understanding of the biology of brain glucagon in the regulation of peripheral homeostasis. Here we compare and contrast brain glucagon action in feeding vs glucose regulation and depict the physiological relevance of brain glucagon by reviewing their actions in two key regions of the central nervous system: the mediobasal hypothalamus and the dorsal vagal complex. These novel findings pave the way to future therapeutic strategies aimed at enhancing brain glucagon action for the treatment of diabetes and obesity. This review summarises a presentation given at the 'Novel data on glucagon' symposium at the 2015 annual meeting of the EASD. It is accompanied by two other reviews on topics from this symposium (by Young Lee and colleagues, DOI: 10.1007/s00125-016-3965-9 ), and by Russell Miller and Morris Birnbaum, DOI: 10.1007/s00125-016-3955-y ) and an overview by the Session Chair, Isabel Valverde (DOI: 10.1007/s00125-016-3946-z ).
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Affiliation(s)
- Mona A Abraham
- Toronto General Hospital Research Institute and Department of Medicine, UHN, Toronto, ON, M5G 1L7, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Tony K T Lam
- Toronto General Hospital Research Institute and Department of Medicine, UHN, Toronto, ON, M5G 1L7, Canada.
- Department of Physiology, University of Toronto, Toronto, ON, Canada.
- Department of Medicine, University of Toronto, Toronto, ON, Canada.
- Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada.
- MaRS Centre, 101 College Street, Toronto Medical Discovery Tower, 10th floor-Room 705, Toronto, ON, M5G 1L7, Canada.
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Pitchaimani V, Arumugam S, Thandavarayan RA, Karuppagounder V, Afrin MR, Sreedhar R, Harima M, Suzuki H, Miyashita S, Suzuki K, Nakamura M, Ueno K, Watanabe K. Hypothalamic glucagon signaling in fasting hypoglycemia. Life Sci 2016; 153:118-23. [PMID: 27084528 DOI: 10.1016/j.lfs.2016.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 03/25/2016] [Accepted: 04/05/2016] [Indexed: 11/18/2022]
Abstract
AIMS Sustained glucagon infusion increases hepatic glucose production, but this effect is transient due to hypothalamic glucagon signaling. In hypoglycemia, glucagon acts as a major defense to sustain the blood glucose level and this raises the question regarding glucagon signaling associated glucose production in prolonged fasting hypoglycemia. In this study, we investigated the proteins associated with hypothalamic glucagon signaling and liver gluconeogenesis during fasting hypoglycemia. MAIN METHODS 8-9week old, male C57BL6/J mice were fasted for 4, 8, 12, 18, 24, 30, 36 or 42h. In the hypothalamus, we investigated glucagon signaling by analyzing the glucagon receptor and its downstream protein, peroxisome proliferator-activated receptor-gamma coactivator 1 (PGC-1) expression. In the liver, we investigated gluconeogenesis by analyzing p-protein kinase A (PKA)(Ser/Thr) substrate and phosphoenolpyruvate carboxykinase - cytosolic (PEPCK-C) expression using the western blotting technique. KEY FINDINGS The elevated or trended higher hypothalamic glucagon receptor and PGC-1 expressions at 18 and 42h were correlated with the attenuated liver p-PKA(Ser/Thr) substrate expression. The attenuated hypothalamic glucagon receptor and PGC-1 expressions at 12, 24, 30 and 36h were correlated with the elevated or trended higher liver p-PKA(Ser/Thr) substrate expression. SIGNIFICANCE The hypothalamic glucagon signaling during fasting hypoglycemia might have been modulated by circadian rhythm and this possibly attenuates the liver p-PKA(Ser/Thr) substrate to modify the gluconeogenesis pathway. This mechanism will help to understand the hyperglucagonemia associated complications in diabetes.
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Affiliation(s)
- Vigneshwaran Pitchaimani
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Somasundaram Arumugam
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | | | - Vengadeshprabhu Karuppagounder
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Mst Rejina Afrin
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Remya Sreedhar
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Meilei Harima
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Hiroshi Suzuki
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Shizuka Miyashita
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Kenji Suzuki
- Department of Gastroenterology, Niigata University of Graduate School of Medicine and Dental Sciences, Niigata City 951-8510, Japan
| | - Masahiko Nakamura
- Department of Cardiology, Yamanashi Prefectural Central Hospital, Kofu, Yamanashi 400-8506, Japan
| | - Kazuyuki Ueno
- Department of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan
| | - Kenichi Watanabe
- Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603, Japan.
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The Effects of Insulin-Induced Hypoglycaemia on Tyrosine Hydroxylase Phosphorylation in Rat Brain and Adrenal Gland. Neurochem Res 2016; 41:1612-24. [PMID: 26935743 DOI: 10.1007/s11064-016-1875-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 02/18/2016] [Indexed: 12/16/2022]
Abstract
In this study we investigated the effects of insulin-induced hypoglycaemia on tyrosine hydroxylase (TH) protein and TH phosphorylation in the adrenal gland, C1 cell group, locus coeruleus (LC) and midbrain dopaminergic cell groups that are thought to play a role in response to hypoglycaemia and compared the effects of different concentrations of insulin in rats. Insulin (1 and 10 U/kg) treatment caused similar reductions in blood glucose concentration (from 7.5-9 to 2-3 mmol/L); however, plasma adrenaline concentration was increased 20-30 fold in response to 10 U/kg insulin and only 14 fold following 1 U/kg. Time course studies (at 10 U/kg insulin) revealed that in the adrenal gland, Ser31 phosphorylation was increased between 30 and 90 min (4-5 fold), implying that TH was activated to increase catecholamine synthesis in adrenal medulla to replenish the stores. In the brain, Ser19 phosphorylation was limited to certain dopaminergic groups in the midbrain, while Ser31 phosphorylation was increased in most catecholaminergic regions at 60 min (1.3-2 fold), suggesting that Ser31 phosphorylation may be an important mechanism to maintain catecholamine synthesis in the brain. Comparing the effects of 1 and 10 U/kg insulin revealed that Ser31 phosphorylation was increased to similar extent in the adrenal gland and C1 cell group in response to both doses whereas Ser31 and Ser19 phosphorylation were only increased in response to 1 U/kg insulin in LC and in response to 10 U/kg insulin in most midbrain regions. Thus, the adrenal gland and some catecholaminergic brain regions become activated in response to insulin administration and brain catecholamines may be important for initiation of physiological defences against insulin-induced hypoglycaemia.
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Lazard D, Vardi P, Bloch K. Anti-diabetic and neuroprotective effects of pancreatic islet transplantation into the central nervous system. Diabetes Metab Res Rev 2016; 32:11-20. [PMID: 25708430 DOI: 10.1002/dmrr.2644] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 02/19/2015] [Indexed: 12/19/2022]
Abstract
During the last decades, the central nervous system (CNS) was intensively tested as a site for islet transplantation in different animal models of diabetes. Immunoprivilege properties of intracranial and intrathecal sites were found to delay and reduce rejection of transplanted allo-islets and xeno-islets, especially in the form of dispersed single cells. Insulin released from islets grafted in CNS was shown to cross the blood-brain barrier and to act as a regulator of peripheral glucose metabolism. In diabetic animals, sufficient nutrition and oxygen supply to islets grafted in the CNS provide adequate insulin response to increase glucose level resulting in rapid normoglycemia. In addition to insulin, pancreatic islets produce and secrete several other hormones, as well as neurotrophic and angiogenic factors with potential neuroprotective properties. Recent experimental studies and clinical trials provide a strong support for delivery of islet-derived macromolecules to CNS as a promising strategy to treat various brain disorders. This review article focuses mainly on analysis of current status of intracranial and intrathecal islet transplantations for treatment of experimental diabetes and discusses the possible neuroprotective properties of grafted islets into CNS as a novel therapeutic approach to brain disorders with cognitive dysfunctions characterized by impaired brain insulin signalling. Copyright © 2015 John Wiley & Sons, Ltd.
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MESH Headings
- Animals
- Blood-Brain Barrier
- Brain
- Central Nervous System
- Diabetes Mellitus, Type 1/blood
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/surgery
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/surgery
- Diabetic Neuropathies/prevention & control
- Disease Models, Animal
- Humans
- Hyperglycemia/prevention & control
- Hypoglycemia/prevention & control
- Insulin/metabolism
- Insulin Resistance
- Insulin Secretion
- Islets of Langerhans Transplantation/adverse effects
- Spinal Cord
- Subarachnoid Space
- Transplantation, Heterologous/adverse effects
- Transplantation, Heterotopic/adverse effects
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Affiliation(s)
- Daniel Lazard
- Laboratory of Diabetes and Obesity Research, Felsenstein Medical Research Center, Sackler School of Medicine, Tel Aviv University, Petah Tikva, Israel
| | - Pnina Vardi
- Laboratory of Diabetes and Obesity Research, Felsenstein Medical Research Center, Sackler School of Medicine, Tel Aviv University, Petah Tikva, Israel
| | - Konstantin Bloch
- Laboratory of Diabetes and Obesity Research, Felsenstein Medical Research Center, Sackler School of Medicine, Tel Aviv University, Petah Tikva, Israel
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30
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Quiñones M, Al-Massadi O, Gallego R, Fernø J, Diéguez C, López M, Nogueiras R. Hypothalamic CaMKKβ mediates glucagon anorectic effect and its diet-induced resistance. Mol Metab 2015; 4:961-70. [PMID: 26909312 PMCID: PMC4731730 DOI: 10.1016/j.molmet.2015.09.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 09/29/2015] [Accepted: 09/30/2015] [Indexed: 01/23/2023] Open
Abstract
Objective Glucagon receptor antagonists and humanized glucagon antibodies are currently studied as promising therapies for obesity and type II diabetes. Among its variety of actions, glucagon reduces food intake, but the molecular mechanisms mediating this effect as well as glucagon resistance are totally unknown. Methods Glucagon and adenoviral vectors were administered in specific hypothalamic nuclei of lean and diet-induced obese rats. The expression of neuropeptides controlling food intake was performed by in situ hybridization. The regulation of factors of the glucagon signaling pathway was assessed by western blot. Results The central injection of glucagon decreased feeding through a hypothalamic pathway involving protein kinase A (PKA)/Ca2+-calmodulin-dependent protein kinase kinase β (CaMKKβ)/AMP-activated protein kinase (AMPK)-dependent mechanism. More specifically, the central injection of glucagon increases PKA activity and reduces protein levels of CaMKKβ and its downstream target phosphorylated AMPK in the hypothalamic arcuate nucleus (ARC). Consistently, central glucagon significantly decreased AgRP expression. Inhibition of PKA and genetic activation of AMPK in the ARC blocked glucagon-induced anorexia in lean rats. Genetic down-regulation of glucagon receptors in the ARC stimulates fasting-induced hyperphagia. Although glucagon was unable to decrease food intake in DIO rats, glucagon sensitivity was restored after inactivation of CaMKKβ, specifically in the ARC. Thus, glucagon decreases food intake acutely via PKA/CaMKKβ/AMPK dependent pathways in the ARC, and CaMKKβ mediates its obesity-induced hypothalamic resistance. Conclusions This work reveals the molecular underpinnings by which glucagon controls feeding that may lead to a better understanding of disease states linked to anorexia and cachexia. Glucagon stimulates PKA and inhibits CaMKKβ and AMPK in the arcuate nucleus (ARC). Down-regulation of glucagon receptor in the ARC increases fasting-induced hyperphagia. Glucagon is unable to decrease food intake in diet-induced obese (DIO) rats. In DIO rats, glucagon fails to alter CaMKKβ and its downstream targets AMPK and pACC. Down-regulation of CaMKKβ in the ARC restores glucagon sensitivity in obese rodents.
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Affiliation(s)
- Mar Quiñones
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Omar Al-Massadi
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Rosalía Gallego
- Department of Morphological Sciences, School of Medicine, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain
| | - Johan Fernø
- Department of Clinical Science, K. G. Jebsen Center for Diabetes Research, University of Bergen, Bergen, Norway
| | - Carlos Diéguez
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Miguel López
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
| | - Ruben Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), 15706, Spain
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31
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Pathak NM, Pathak V, Lynch AM, Irwin N, Gault VA, Flatt PR. Stable oxyntomodulin analogues exert positive effects on hippocampal neurogenesis and gene expression as well as improving glucose homeostasis in high fat fed mice. Mol Cell Endocrinol 2015; 412:95-103. [PMID: 26048772 DOI: 10.1016/j.mce.2015.05.035] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 05/26/2015] [Accepted: 05/29/2015] [Indexed: 01/05/2023]
Abstract
The weight-lowering and gluco-regulatory actions of oxyntomodulin (Oxm) have been well-documented however potential actions of this peptide in brain regions associated with learning and memory have not yet been evaluated. The present study examined the long-term actions of a stable acylated analogue of Oxm, (dS(2))Oxm(K-γ-glu-Pal), together with parent (dS(2))Oxm peptide, on hippocampal neurogenesis, gene expression and metabolic control in high fat (HF) mice. Groups of HF mice (n = 12) received twice-daily injections of Oxm analogues (both at 25 nmol/kg body weight) or saline vehicle (0.9% wt/vol) over 28 days. Hippocampal gene expression and histology were assessed together with evaluation of energy intake, body weight, non-fasting glucose and insulin, glucose tolerance, insulin sensitivity and lipids. Oxm analogues significantly reduced body weight, improved glucose tolerance, glucose-mediated insulin secretion, insulin sensitivity, islet architecture and lipid profile. Analysis of brain histology revealed significant reduction in hippocampal oxidative damage (8-oxoguanine), enhanced hippocampal neurogenesis (doublecortin) and improved hippocampal and cortical synaptogenesis (synaptophysin) following treatment. Furthermore, Oxm analogues up-regulated hippocampal mRNA expression of MASH1, Synaptophysin, SIRT1, GLUT4 and IRS1, and down-regulated expression of LDL-R and GSK3β. These data demonstrate potential of stable Oxm analogues, and particularly (dS(2))Oxm(K-γ-glu-Pal) to improve metabolic function and enhance neurogenesis, synaptic plasticity, insulin signalling and exert protective effects against oxidative damage in hippocampus and cortex brain regions in HF mice.
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Affiliation(s)
- N M Pathak
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK
| | - V Pathak
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK
| | - A M Lynch
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK
| | - N Irwin
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK
| | - V A Gault
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK.
| | - P R Flatt
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, UK
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LaPierre MP, Abraham MA, Yue JTY, Filippi BM, Lam TKT. Glucagon signalling in the dorsal vagal complex is sufficient and necessary for high-protein feeding to regulate glucose homeostasis in vivo. EMBO Rep 2015; 16:1299-307. [PMID: 26290496 DOI: 10.15252/embr.201540492] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 07/23/2015] [Indexed: 11/09/2022] Open
Abstract
High-protein feeding acutely lowers postprandial glucose concentration compared to low-protein feeding, despite a dichotomous rise of circulating glucagon levels. The physiological role of this glucagon rise has been largely overlooked. We here first report that glucagon signalling in the dorsal vagal complex (DVC) of the brain is sufficient to lower glucose production by activating a Gcgr-PKA-ERK-KATP channel signalling cascade in the DVC of rats in vivo. We further demonstrate that direct blockade of DVC Gcgr signalling negates the acute ability of high- vs. low-protein feeding to reduce plasma glucose concentration, indicating that the elevated circulating glucagon during high-protein feeding acts in the brain to lower plasma glucose levels. These data revise the physiological role of glucagon and argue that brain glucagon signalling contributes to glucose homeostasis during dietary protein intake.
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Affiliation(s)
- Mary P LaPierre
- Toronto General Research Institute & Department of Medicine UHN, Toronto, Canada Department of Physiology, University of Toronto, Toronto Canada
| | - Mona A Abraham
- Toronto General Research Institute & Department of Medicine UHN, Toronto, Canada Department of Physiology, University of Toronto, Toronto Canada
| | - Jessica T Y Yue
- Toronto General Research Institute & Department of Medicine UHN, Toronto, Canada
| | - Beatrice M Filippi
- Toronto General Research Institute & Department of Medicine UHN, Toronto, Canada
| | - Tony K T Lam
- Toronto General Research Institute & Department of Medicine UHN, Toronto, Canada Department of Physiology, University of Toronto, Toronto Canada Department of Medicine, University of Toronto, Toronto Canada Banting and Best Diabetes Centre, University of Toronto, Toronto, Canada
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33
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Cegla J, Troke RC, Jones B, Tharakan G, Kenkre J, McCullough KA, Lim CT, Parvizi N, Hussein M, Chambers ES, Minnion J, Cuenco J, Ghatei MA, Meeran K, Tan TM, Bloom SR. Coinfusion of low-dose GLP-1 and glucagon in man results in a reduction in food intake. Diabetes 2014; 63:3711-20. [PMID: 24939425 DOI: 10.2337/db14-0242] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Obesity is a growing epidemic, and current medical therapies have proven inadequate. Endogenous satiety hormones provide an attractive target for the development of drugs that aim to cause effective weight loss with minimal side effects. Both glucagon and GLP-1 reduce appetite and cause weight loss. Additionally, glucagon increases energy expenditure. We hypothesized that the combination of both peptides, administered at doses that are individually subanorectic, would reduce appetite, while GLP-1 would protect against the hyperglycemic effect of glucagon. In this double-blind crossover study, subanorectic doses of each peptide alone, both peptides in combination, or placebo was infused into 13 human volunteers for 120 min. An ad libitum meal was provided after 90 min, and calorie intake determined. Resting energy expenditure was measured by indirect calorimetry at baseline and during infusion. Glucagon or GLP-1, given individually at subanorectic doses, did not significantly reduce food intake. Coinfusion at the same doses led to a significant reduction in food intake of 13%. Furthermore, the addition of GLP-1 protected against glucagon-induced hyperglycemia, and an increase in energy expenditure of 53 kcal/day was seen on coinfusion. These observations support the concept of GLP-1 and glucagon dual agonism as a possible treatment for obesity and diabetes.
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Affiliation(s)
- Jaimini Cegla
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - Rachel C Troke
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - Ben Jones
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - George Tharakan
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - Julia Kenkre
- Section of Investigative Medicine, Imperial College London, London, U.K
| | | | - Chung Thong Lim
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - Nassim Parvizi
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - Mohamed Hussein
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - Edward S Chambers
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - James Minnion
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - Joyceline Cuenco
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - Mohammad A Ghatei
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - Karim Meeran
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - Tricia M Tan
- Section of Investigative Medicine, Imperial College London, London, U.K
| | - Stephen R Bloom
- Section of Investigative Medicine, Imperial College London, London, U.K.
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Abstract
Glucose homeostasis is precisely regulated by glucagon and insulin, which are released by pancreatic α- and β-cells, respectively. While β-cells have been the focus of intense research, less is known about α-cell function and the actions of glucagon. In recent years, the study of this endocrine cell type has experienced a renewed drive. The present review contains a summary of established concepts as well as new information about the regulation of α-cells by glucose, amino acids, fatty acids and other nutrients, focusing especially on glucagon release, glucagon synthesis and α-cell survival. We have also discussed the role of glucagon in glucose homeostasis and in energy and lipid metabolism as well as its potential as a modulator of food intake and body weight. In addition to the well-established action on the liver, we discuss the effects of glucagon in other organs, where the glucagon receptor is expressed. These tissues include the heart, kidneys, adipose tissue, brain, small intestine and the gustatory epithelium. Alterations in α-cell function and abnormal glucagon concentrations are present in diabetes and are thought to aggravate the hyperglycaemic state of diabetic patients. In this respect, several experimental approaches in diabetic models have shown important beneficial results in improving hyperglycaemia after the modulation of glucagon secretion or action. Moreover, glucagon receptor agonism has also been used as a therapeutic strategy to treat obesity.
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35
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LaPierre MP, Abraham MA, Filippi BM, Yue JTY, Lam TKT. Glucagon and lipid signaling in the hypothalamus. Mamm Genome 2014; 25:434-41. [DOI: 10.1007/s00335-014-9510-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 03/25/2014] [Indexed: 12/12/2022]
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Filippi BM, Abraham MA, Yue JTY, Lam TKT. Insulin and glucagon signaling in the central nervous system. Rev Endocr Metab Disord 2013; 14:365-75. [PMID: 23959343 DOI: 10.1007/s11154-013-9258-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The prevalence of the obesity and diabetes epidemic has triggered tremendous research investigating the role of the central nervous system (CNS) in the regulation of food intake, body weight gain and glucose homeostasis. This invited review focuses on the role of two pancreatic hormones--insulin and glucagon--that trigger signaling pathways in the brain to regulate energy and glucose homeostasis. Unlike in the periphery, insulin and glucagon signaling in the CNS does not seem to have opposing metabolic effects, as both hormones exert a suppressive effect on food intake and weight gain. They signal through different pathways and alter different neuronal populations suggesting a complementary action of the two hormones in regulating feeding behavior. Similar to its systemic effect, insulin signaling in the brain lowers glucose production. However, the ability of glucagon signaling in the brain to regulate glucose production remains unknown. Future studies that aim to dissect insulin and glucagon signaling in the CNS that regulate energy and glucose homeostasis could unveil novel signaling molecules to lower body weight and glucose levels in obesity and diabetes.
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Kasote DM, Hegde MV, Katyare SS. Mitochondrial dysfunction in psychiatric and neurological diseases: cause(s), consequence(s), and implications of antioxidant therapy. Biofactors 2013; 39:392-406. [PMID: 23460132 DOI: 10.1002/biof.1093] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 12/25/2012] [Indexed: 12/12/2022]
Abstract
Mitochondrial dysfunction is at the base of development and progression of several psychiatric and neurologic diseases with different etiologies. MtDNA/nDNA mutational damage, failure of endogenous antioxidant defenses, hormonal malfunction, altered membrane permeability, metabolic dysregulation, disruption of calcium buffering capacity and ageing have been found to be the root causes of mitochondrial dysfunction in psychatric and neurodegenerative diseases. However, the overall consequences of mitochondrial dysfunction are only limited to increase in oxidative/nitrosative stress and cellular energy crises. Thus far, extensive efforts have been made to improve mitochondrial function through specific cause-dependent antioxidant therapy. However, owing to complex genetic and interlinked causes of mitochondrial dysfunction, it has not been possible to achieve any common, unique supportive antioxidant therapeutic strategy for the treatment of psychiatric and neurologic diseases. Hence, we propose an antioxidant therapeutic strategy for management of consequences of mitochondrial dysfunction in psychiatric and neurologic diseases. It is expected that this will not only reduces oxidative stress, but also promote anaerobic energy production.
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Affiliation(s)
- Deepak M Kasote
- MACS-Agharkar Research Institute, G.G. Agarkar Road, Pune, MS, India.
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Hypothalamic glucagon signaling inhibits hepatic glucose production. Nat Med 2013; 19:766-72. [DOI: 10.1038/nm.3115] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 01/31/2013] [Indexed: 01/28/2023]
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Parker JA, McCullough KA, Field BCT, Minnion JS, Martin NM, Ghatei MA, Bloom SR. Glucagon and GLP-1 inhibit food intake and increase c-fos expression in similar appetite regulating centres in the brainstem and amygdala. Int J Obes (Lond) 2013; 37:1391-8. [PMID: 23337772 DOI: 10.1038/ijo.2012.227] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 11/30/2012] [Accepted: 12/10/2012] [Indexed: 01/01/2023]
Abstract
BACKGROUND Glucagon and glucagon-like peptide-1 (GLP-1) are evolutionarily related anorectic hormones. Glucagon also increases energy expenditure. The combination of glucagon and GLP-1 could cause weight loss through a simultaneous reduction in food intake and increased energy expenditure. However, the effect of combined administration of glucagon and GLP-1 on food intake and neuronal activation has not previously been studied. Furthermore, the effect of glucagon on neuronal activation in appetite regulating centres has not been assessed. Characterisation of the effects of glucagon when administered singly and in combination with GLP-1 on neuronal activation will be important for determining the mechanism of action of related potential antiobesity therapies. OBJECTIVES To investigate the effects of peripherally administered GLP-1 and glucagon on food intake, neuronal activation and blood glucose in mice when administered individually and in combination. METHODOLOGY Food intake, blood glucose and c-fos expression in the hypothalamus, amygdala and brainstem were measured in response to GLP-1 and glucagon, alone and in combination. RESULTS Peripherally administered GLP-1 and glucagon decreased food intake and increased c-fos expression in the brainstem and amygdala. Doses of GLP-1 and glucagon that individually did not significantly affect feeding, in combination were anorectic and stimulated neuronal activation in the area postrema (AP) and central nucleus of the amygdala. Combined administration of GLP-1 and glucagon prevented the acute hyperglycemic effect of glucagon alone. CONCLUSION Anorectic doses of glucagon and GLP-1 induced similar patterns of c-fos expression. Combined administration of low dose GLP-1 and glucagon inhibited food intake and induced c-fos expression in the AP and amygdala. The combination of both hormones may offer the opportunity to utilise the beneficial effects of reduced food intake and increased energy expenditure, and may therefore be a potential treatment for obesity.
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Affiliation(s)
- J A Parker
- Hammersmith Hospital, Section of Investigative Medicine, Imperial College London, London, UK
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40
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Lockie SH, Heppner KM, Chaudhary N, Chabenne JR, Morgan DA, Veyrat-Durebex C, Ananthakrishnan G, Rohner-Jeanrenaud F, Drucker DJ, DiMarchi R, Rahmouni K, Oldfield BJ, Tschöp MH, Perez-Tilve D. Direct control of brown adipose tissue thermogenesis by central nervous system glucagon-like peptide-1 receptor signaling. Diabetes 2012; 61:2753-62. [PMID: 22933116 PMCID: PMC3478556 DOI: 10.2337/db11-1556] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We studied interscapular brown adipose tissue (iBAT) activity in wild-type (WT) and glucagon-like peptide 1 receptor (GLP-1R)-deficient mice after the administration of the proglucagon-derived peptides (PGDPs) glucagon-like peptide (GLP-1), glucagon (GCG), and oxyntomodulin (OXM) directly into the brain. Intracerebroventricular injection of PGDPs reduces body weight and increases iBAT thermogenesis. This was independent of changes in feeding and insulin responsiveness but correlated with increased activity of sympathetic fibers innervating brown adipose tissue (BAT). Despite being a GCG receptor agonist, OXM requires GLP-1R activation to induce iBAT thermogenesis. The increase in thermogenesis in WT mice correlates with increased expression of genes upregulated by adrenergic signaling and required for iBAT thermogenesis, including PGC1a and UCP-1. In spite of the increase in iBAT thermogenesis induced by GLP-1R activation in WT mice, Glp1r(-/-) mice exhibit a normal response to cold exposure, demonstrating that endogenous GLP-1R signaling is not essential for appropriate thermogenic response after cold exposure. Our data suggest that the increase in BAT thermogenesis may be an additional mechanism whereby pharmacological GLP-1R activation controls energy balance.
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Affiliation(s)
- Sarah H. Lockie
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, Ohio
- Department of Physiology, Monash University, Melbourne, Australia
| | - Kristy M. Heppner
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, Ohio
| | - Nilika Chaudhary
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, Ohio
| | | | - Donald A. Morgan
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Christelle Veyrat-Durebex
- Department of Internal Medicine, Laboratory of Metabolism, Division of Endocrinology, Diabetology and Nutrition, University of Geneva, Geneva, Switzerland
| | - Gayathri Ananthakrishnan
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, Ohio
| | - Françoise Rohner-Jeanrenaud
- Department of Internal Medicine, Laboratory of Metabolism, Division of Endocrinology, Diabetology and Nutrition, University of Geneva, Geneva, Switzerland
| | - Daniel J. Drucker
- Department of Medicine, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Richard DiMarchi
- Department of Chemistry, Indiana University, Bloomington, Indiana
| | - Kamal Rahmouni
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | | | - Matthias H. Tschöp
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, Ohio
| | - Diego Perez-Tilve
- Department of Internal Medicine, Metabolic Disease Institute, University of Cincinnati, Cincinnati, Ohio
- Corresponding author: Diego Perez-Tilve,
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Abstract
In recent years the actions of intracellular-acting, extracellular signaling proteins/peptides (intracrines) have become increasingly defined. General principles of intracrine action have been proposed. Mitochondria represent one locus of intracrine action, and thus far, angiotensin II, transforming growth factor-beta, growth hormone, atrial natriuretic peptide, Wnt 13, stanniocalcin, other renin-angiotensin system components, and vascular endothelial-derived growth factor, among others, have been shown to be mitochondria-localizing intracrines. The implications of this mitochondrial intracrine biology are discussed.
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Affiliation(s)
- Richard N Re
- Ochsner Clinic Foundation, 1514 Jefferson Hwy., New Orleans, LA 70121, USA.
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Kurose Y, Kamisoyama H, Honda K, Azuma Y, Sugahara K, Hasegawa S, Kobayashi S. Effects of central administration of glucagon on feed intake and endocrine responses in sheep. Anim Sci J 2010; 80:686-90. [PMID: 20163659 DOI: 10.1111/j.1740-0929.2009.00685.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study was conducted to investigate effects of glucagon intracerebroventricularly administered on feed intake and endocrine changes in sheep. Four male sheep (48-55 kg BW) were used. The animals were acclimatized to be fed alfalfa hay cubes at 12.00 hour. Human glucagon (40 and 80 microg/0.5 mL) was injected into the lateral ventricle at 12.00 hour. Blood samples were taken every 10 min from 30 min before to 180 min after the glucagon injection. Soon after the injection, the animals were given alfalfa hay cubes, and the amounts of the feed eaten within 2 h were measured. Feed intakes were significantly (P < 0.05) suppressed by 80 microg of glucagon. Plasma glucose levels in control animals were gradually decreased after the feeding, whilst those in glucagon-treated animals were temporarily elevated just after the feeding and then kept higher than control levels. Plasma insulin was abruptly elevated after the feeding and was maintained at higher levels than before the feeding in all treatments. Plasma NEFA concentrations were decreased after the feeding in all treatments. A tendency of increase in plasma cortisol levels occurred in glucagon-injected animals. The present study provides the first evidence that glucagon directly acts on the brain, then inhibiting feeding behavior and inducing endocrine responses in ruminants.
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Affiliation(s)
- Yohei Kurose
- Laboratory of Animal Nutrition, Faculty of Animal Science, Kitasato University, Towada, Aomori, Japan.
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43
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Jalilian AR, Jouiaei M, Doroudi A, Garousi J, Moradkhani S. Preparation and biological evaluation of radiogallium labeled glucagon for SPECT imaging. J Radioanal Nucl Chem 2010. [DOI: 10.1007/s10967-010-0555-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ali S, Drucker DJ. Benefits and limitations of reducing glucagon action for the treatment of type 2 diabetes. Am J Physiol Endocrinol Metab 2009; 296:E415-21. [PMID: 19116373 DOI: 10.1152/ajpendo.90887.2008] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Glucagon is secreted from the alpha-cells of the pancreatic islets and regulates glucose homeostasis through modulation of hepatic glucose production. As elevated glucagon levels contribute to the pathophysiology of hyperglycemia in subjects with type 2 diabetes, reduction of glucagon receptor gene (Gcgr) activity represents a potential target for the treatment of T2DM. Herein, we review current concepts of glucagon action in hepatic and extrahepatic tissues and evaluate the therapeutic potential, mechanisms of action, and safety of reducing Gcgr signaling for the treatment of T2DM.
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Affiliation(s)
- Safina Ali
- Mt. Sinai Hospital, Toronto, ON, Canada M5T 3L9
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45
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Nagell CF, Pedersen JF, Holst JJ. The antagonistic metabolite of GLP-1, GLP-1 (9-36)amide, does not influence gastric emptying and hunger sensations in man. Scand J Gastroenterol 2007; 42:28-33. [PMID: 17190759 DOI: 10.1080/00365520600780262] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Glucagon-like peptide-1 (GLP-1 (7-36)amide) is an intestinal hormone that is released in response to meal ingestion. GLP-1 reduces postprandial gastric and exocrine pancreatic secretion and is believed to inhibit gastric emptying. Furthermore, GLP-1 may play a role in hunger and thirst regulation. In vivo, GLP-1 is rapidly (within minutes) converted into a metabolite, GLP-1 (9-36)amide, which has been shown to act as a GLP-1 receptor antagonist in vitro and in anaesthetized pigs. The purpose of this study was to assess the effect of infusion of GLP-1 (9-36)amide on hunger ratings and antral emptying of a meal. MATERIAL AND METHODS Six healthy volunteers were tested in a double-blind, placebo-controlled fashion. Antral emptying of a liquid meal and hunger ratings were determined using ultrasound technology and visual analogue scale scoring during infusions of saline or GLP-1 (9-36)amide (5 pmol/kg body wt/min) resulting in supraphysiological concentrations. RESULTS Infusion of GLP-1 (9-36)amide had no effect on gastric emptying or the sensation of hunger compared to saline. CONCLUSIONS Our findings suggests that the rapid formation of the antagonistic metabolite does not influence gastric emptying and hunger ratings in humans even when it is present in supraphysiological concentrations.
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46
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Bobe G, Ametaj BN, Young JW, Anderson LL, Beitz DC. Exogenous glucagon effects on health and reproductive performance of lactating dairy cows with mild fatty liver. Anim Reprod Sci 2006; 102:194-207. [PMID: 17126505 DOI: 10.1016/j.anireprosci.2006.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Accepted: 11/01/2006] [Indexed: 11/28/2022]
Abstract
Severe fatty liver, a metabolic disease of dairy cows in early lactation, results in decreased health and reproductive performance, but can be alleviated by treatment with i.v. injections of glucagon. Mild fatty liver in cows effects on health and reproductive performance were determined by treatment with 14-day s.c. injections of glucagon at 7.5 or 15 mg/day. Multiparous Holstein cows (n=32) were grouped into Normal and Susceptible based on liver triacylglycerol concentrations (>1% liver tissue biopsy wet weight) at day 8 postpartum (day 0=day of parturition). Susceptible cows (n=24) were assigned randomly to three groups and s.c. injected with 0mg glucagon [60 ml 0.15M NaCl] [n=8] (same for Normal cows), 2.5 mg glucagon, or 5 mg glucagon every 8 h for 14 days, beginning day 8 postpartum. Mild fatty liver resulted in an increased number of days with elevated body temperature during the injection period, an increased incidence of mastitis after glucagon treatment, increased days to first estrus and insemination, increased days before conception occurred, and decreased conception rate. In cows with mild fatty liver, glucagon (15 mg/day) decreased the number of days with elevated body temperature and the incidence of mastitis after hormone treatment. From these results, we suggest that mild fatty liver is detrimental to health and reproduction of dairy cows and, furthermore, that exogenous glucagon decreases some of these detrimental effects.
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Affiliation(s)
- G Bobe
- Nutritional Physiology Group, Department of Animal Science, Iowa State University, 313 Kildee Hall, Ames, IA 50011-3150, USA
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Volgin DV, Kubin L. Chronic intermittent hypoxia alters hypothalamic transcription of genes involved in metabolic regulation. Auton Neurosci 2006; 126-127:93-9. [PMID: 16730240 DOI: 10.1016/j.autneu.2006.03.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 03/09/2006] [Accepted: 03/28/2006] [Indexed: 11/23/2022]
Abstract
Epidemiological studies show that the obstructive sleep apnea syndrome (OSAS) is strongly associated with obesity, hypertension and diabetes, the three conditions characteristic of the metabolic syndrome. Since metabolic disorders usually involve altered homeostatic mechanisms both centrally and peripherally, it is likely that so it is in OSAS, but the underlying mechanisms remain largely unknown. We used an established rodent model to test whether chronic intermittent hypoxia (CIH) similar to that experienced by OSAS patients leads to distinct and relevant for metabolic regulation transcriptional changes in the posterior hypothalamus. Using quantitative reverse transcription-polymerase chain reaction, we found that rats exposed to CIH for 35 days (n=9) had twice higher levels of the adrenergic alpha2A receptor mRNA than the rats simultaneously submitted to a matching sham treatment (n=9). The mRNA levels of three members of the family of signal transducers and activators of transcription, STAT1, STAT3 and STAT5b, were also increased 2-4 times. The increases occurred only in the perifornical region, whereas no changes were detected in the ventromedial region comprising the ventromedial and arcuate nuclei or the dorsomedial region comprising the dorsomedial and paraventricular nuclei. These results show that, at least at the transcriptional level, CIH exerts a distinct and regionally selective central effect on the expression of selected mRNAs involved in metabolic regulation through adrenergic, leptinergic and inflammatory pathways.
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Affiliation(s)
- Denys V Volgin
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104-6046, USA
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Nagell CF, Wettergren A, Ørskov C, Holst JJ. Inhibitory effect of GLP-1 on gastric motility persists after vagal deafferentation in pigs. Scand J Gastroenterol 2006; 41:667-72. [PMID: 16716964 DOI: 10.1080/00365520500408253] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Glucagon-like peptide 1 (GLP-1) is an intestinal hormone that is secreted in response to meal ingestion. GLP-1 inhibits gastric emptying and reduces postprandial gastric secretion and may play a physiological regulatory role in controlling appetite and energy intake in humans. The GLP-1 receptors have been identified in several organs including the stomach, brain and pancreas. The GLP-1 mechanism of action on insulin secretion is at least partly mediated via receptors on the pancreatic islet, but the mechanism by which GLP-1 retards gastric emptying is not known and may involve neural interactions, although GLP-1 has no effect on vagally stimulated motor activity of the isolated porcine antrum. MATERIAL AND METHODS Previously, an experimental model was developed with centrally (insulin hypoglycaemia) induced vagally mediated stimulation of antral motility, recorded by force transducers, in anaesthetized pigs. This model has now been developed further to include vagal deafferentation to determine the role of the afferent vagus in mediating the inhibitory effect of GLP-1 on gastric motility. RESULTS Intravenous infusion of GLP-1 resulting in slightly supraphysiological plasma levels inhibited the antral contractile force, with the amplitude falling from 29.9+/-5.7 mm to 14.6+/-3.5 mm (p<0.001). After vagal deafferentation GLP-1 still inhibited antral motility (from 36.6+/-6.4 mm to 25+/-4.4 mm (p<0.019). The decrease in amplitude was the same before and after deafferentation. CONCLUSIONS GLP-1 significantly inhibited centrally induced antral motility and the inhibitory effect of GLP-1 on gastric motility persisted after vagal deafferentation, supporting the hypothesis that the inhibitory effect results from direct interaction of GLP with receptors in the CNS, which in turn reduce vagal efferent output.
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Affiliation(s)
- Carl Frederik Nagell
- Department of Medical Physiology, The Panum Institute, University of Copenhagen, Denmark
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49
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Alvarez E, Martínez MD, Roncero I, Chowen JA, García-Cuartero B, Gispert JD, Sanz C, Vázquez P, Maldonado A, de Cáceres J, Desco M, Pozo MA, Blázquez E. The expression of GLP-1 receptor mRNA and protein allows the effect of GLP-1 on glucose metabolism in the human hypothalamus and brainstem. J Neurochem 2005; 92:798-806. [PMID: 15686481 DOI: 10.1111/j.1471-4159.2004.02914.x] [Citation(s) in RCA: 199] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In the present work, several experimental approaches were used to determine the presence of the glucagon-like peptide-1 receptor (GLP-1R) and the biological actions of its ligand in the human brain. In situ hybridization histochemistry revealed specific labelling for GLP-1 receptor mRNA in several brain areas. In addition, GLP-1R, glucose transporter isoform (GLUT-2) and glucokinase (GK) mRNAs were identified in the same cells, especially in areas of the hypothalamus involved in feeding behaviour. GLP-1R gene expression in the human brain gave rise to a protein of 56 kDa as determined by affinity cross-linking assays. Specific binding of 125I-GLP-1(7-36) amide to the GLP-1R was detected in several brain areas and was inhibited by unlabelled GLP-1(7-36) amide, exendin-4 and exendin (9-39). A further aim of this work was to evaluate cerebral-glucose metabolism in control subjects by positron emission tomography (PET), using 2-[F-18] deoxy-D-glucose (FDG). Statistical analysis of the PET studies revealed that the administration of GLP-1(7-36) amide significantly reduced (p < 0.001) cerebral glucose metabolism in hypothalamus and brainstem. Because FDG-6-phosphate is not a substrate for subsequent metabolic reactions, the lower activity observed in these areas after peptide administration may be due to reduction of the glucose transport and/or glucose phosphorylation, which should modulate the glucose sensing process in the GLUT-2- and GK-containing cells.
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Affiliation(s)
- Elvira Alvarez
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Complutense University, Madrid, Spain
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50
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Mayo KE, Miller LJ, Bataille D, Dalle S, Göke B, Thorens B, Drucker DJ. International Union of Pharmacology. XXXV. The glucagon receptor family. Pharmacol Rev 2003; 55:167-94. [PMID: 12615957 DOI: 10.1124/pr.55.1.6] [Citation(s) in RCA: 332] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Peptide hormones within the secretin-glucagon family are expressed in endocrine cells of the pancreas and gastrointestinal epithelium and in specialized neurons in the brain, and subserve multiple biological functions, including regulation of growth, nutrient intake, and transit within the gut, and digestion, energy absorption, and energy assimilation. Glucagon, glucagon-like peptide-1, glucagon-like peptide-2, glucose-dependent insulinotropic peptide, growth hormone-releasing hormone and secretin are structurally related peptides that exert their actions through unique members of a structurally related G protein-coupled receptor class 2 family. This review discusses advances in our understanding of how these peptides exert their biological activities, with a focus on the biological actions and structural features of the cognate receptors. The receptors have been named after their parent and only physiologically relevant ligand, in line with the recommendations of the International Union of Pharmacology Committee on Receptor Nomenclature and Drug Classification (NC-IUPHAR).
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Affiliation(s)
- Kelly E Mayo
- Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois, USA
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