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Mazzini G, Le Foll C, Boyle CN, Garelja ML, Zhyvoloup A, Miller MET, Hay DL, Raleigh DP, Lutz TA. The processing intermediate of human amylin, pro-amylin(1-48), has in vivo and in vitro bioactivity. Biophys Chem 2024; 308:107201. [PMID: 38452520 PMCID: PMC11223094 DOI: 10.1016/j.bpc.2024.107201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/31/2024] [Accepted: 02/13/2024] [Indexed: 03/09/2024]
Abstract
Amylin is released by pancreatic beta-cells in response to a meal and its major soluble mature form (37 amino acid-peptide) produces its biological effects by activating amylin receptors. Amylin is derived from larger propeptides that are processed within the synthesizing beta-cell. There are suggestions that a partially processed form, pro-amylin(1-48) is also secreted. We tested the hypothesis that pro-amylin(1-48) has biological activity and that human pro-amylin(1-48) may also form toxic pre-amyloid species. Amyloid formation, the ability to cross-seed and in vitro toxicity were similar between human pro-amylin(1-48) and amylin. Human pro-amylin(1-48) was active at amylin-responsive receptors, though its potency was reduced at rat, but not human amylin receptors. Pro-amylin(1-48) was able to promote anorexia by activating neurons of the area postrema, amylin's primary site of action, indicating that amylin can tolerate significant additions at the N-terminus without losing bioactivity. Our studies help to shed light on the possible roles of pro-amylin(1-48) which may be relevant for the development of future amylin-based drugs.
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Affiliation(s)
- Giulia Mazzini
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Christelle Le Foll
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Christina N Boyle
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Michael L Garelja
- Department of Pharmacology and Toxicology, University of Otago, New Zealand
| | - Alexander Zhyvoloup
- Research Department of Structural and Molecular Biology, University College London, UK
| | | | - Debbie L Hay
- Department of Pharmacology and Toxicology, University of Otago, New Zealand.
| | - Daniel P Raleigh
- Research Department of Structural and Molecular Biology, University College London, UK; Department of Chemistry, Stony Brook University, USA; Laufer Center for Quantitative Biology Stony Brook University, USA.
| | - Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
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2
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Guglielmi V, Bettini S, Sbraccia P, Busetto L, Pellegrini M, Yumuk V, Colao AM, El Ghoch M, Muscogiuri G. Beyond Weight Loss: Added Benefits Could Guide the Choice of Anti-Obesity Medications. Curr Obes Rep 2023:10.1007/s13679-023-00502-7. [PMID: 37209215 DOI: 10.1007/s13679-023-00502-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/29/2023] [Indexed: 05/22/2023]
Abstract
PURPOSE OF REVIEW To highlight the added benefits of approved and upcoming, centrally-acting, anti-obesity drugs, focusing not only on the most common metabolic and cardiovascular effects but also on their less explored clinical benefits and drawbacks, in order to provide clinicians with a tool for more comprehensive, pharmacological management of obesity. RECENT FINDINGS Obesity is increasingly prevalent worldwide and has become a challenge for healthcare systems and societies. Reduced life expectancy and cardiometabolic complications are some of the consequences of this complex disease. Recent insights into the pathophysiology of obesity have led to the development of several promising pharmacologic targets, so that even more effective drugs are on the horizon. The perspective of having a wider range of treatments increases the chance to personalize therapy. This primarily has the potential to take advantage of the long-term use of anti-obesity medication for safe, effective and sustainable weight loss, and to concomitantly address obesity complications/comorbidities when already established. The evolving scenario of the availability of anti-obesity drugs and the increasing knowledge of their added effects on obesity complications will allow clinicians to move into a new era of precision medicine.
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Affiliation(s)
- Valeria Guglielmi
- Dept. of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
- Internal Medicine Unit - Obesity Center, University Hospital Policlinico Tor Vergata, Rome, Italy
| | - Silvia Bettini
- Center for the Study and the Integrated Treatment of Obesity, Internal Medicine 3, Padua University Hospital, Padua, Italy
| | - Paolo Sbraccia
- Dept. of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
- Internal Medicine Unit - Obesity Center, University Hospital Policlinico Tor Vergata, Rome, Italy
| | - Luca Busetto
- Center for the Study and the Integrated Treatment of Obesity, Internal Medicine 3, Padua University Hospital, Padua, Italy
| | - Massimo Pellegrini
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41121, Modena, Italy
| | - Volkan Yumuk
- Division of Endocrinology, Metabolism & Diabetes Istanbul University Cerrahpaşa Medical Faculty, Istanbul, Türkiye
| | - Anna Maria Colao
- Italian Centre for the Care and Well-Being of Patients With Obesity (C.I.B.O), Dipartimento Di Medicina Clinica E Chirurgia, Università Federico II, 80131, Naples, Italy
- Dipartimento Di Medicina Clinica E Chirurgia, Diabetologia E Andrologia, Unità Di Endocrinologia, Università Degli Studi Di Napoli Federico II, Via Sergio Pansini 5, 80131, Naples, Italy
- Cattedra Unesco "Educazione Alla Salute E Allo Sviluppo Sostenibile", University Federico II, Naples, Italy
| | - Marwan El Ghoch
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Beirut Arab University, P.O. Box 11-5020, Riad El Solh, Beirut, Lebanon
| | - Giovanna Muscogiuri
- Dipartimento Di Medicina Clinica E Chirurgia, Diabetologia E Andrologia, Unità Di Endocrinologia, Università Degli Studi Di Napoli Federico II, Via Sergio Pansini 5, 80131, Naples, Italy.
- Cattedra Unesco "Educazione Alla Salute E Allo Sviluppo Sostenibile", University Federico II, Naples, Italy.
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Feris F, McRae A, Kellogg TA, McKenzie T, Ghanem O, Acosta A. Mucosal and hormonal adaptations after Roux-en-Y gastric bypass. Surg Obes Relat Dis 2023; 19:37-49. [PMID: 36243547 PMCID: PMC9797451 DOI: 10.1016/j.soard.2022.08.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 01/12/2023]
Abstract
The aim of this study was to perform a comprehensive literature review regarding the relevant hormonal and histologic changes observed after Roux-en-Y gastric bypass (RYGB). We aimed to describe the relevant hormonal (glucagon-like peptides 1 and 2 [GLP-1 and GLP-2], peptide YY [PYY], oxyntomodulin [OXM], bile acids [BA], cholecystokinin [CCK], ghrelin, glucagon, gastric inhibitory polypeptide [GIP], and amylin) profiles, as well as the histologic (mucosal cellular) adaptations happening after patients undergo RYGB. Our review compiles the current evidence and furthers the understanding of the rationale behind the food intake regulatory adaptations occurring after RYGB surgery. We identify gaps in the literature where the potential for future investigations and therapeutics may lie. We performed a comprehensive database search without language restrictions looking for RYGB bariatric surgery outcomes in patients with pre- and postoperative blood work hormonal profiling and/or gut mucosal biopsies. We gathered the relevant study results and describe them in this review. Where human findings were lacking, we included animal model studies. The amalgamation of physiologic, metabolic, and cellular adaptations following RYGB is yet to be fully characterized. This constitutes a fundamental aspiration for enhancing and individualizing obesity therapy.
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Affiliation(s)
- Fauzi Feris
- Precision Medicine for Obesity Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Alison McRae
- Precision Medicine for Obesity Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Todd A Kellogg
- Division of Endocrine and Metabolic Surgery, Department of Surgery, Mayo Clinic, Rochester, Minnesota
| | - Travis McKenzie
- Division of Endocrine and Metabolic Surgery, Department of Surgery, Mayo Clinic, Rochester, Minnesota
| | - Omar Ghanem
- Division of Endocrine and Metabolic Surgery, Department of Surgery, Mayo Clinic, Rochester, Minnesota
| | - Andres Acosta
- Precision Medicine for Obesity Program, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota.
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Chen Y, Li Q, Li X, Liu H, Li P, Hai R, Guo Y, Wang S, Wang K, Du C. Amylin regulates testosterone levels via steroidogenesis-related enzymes in the central nervous system of male mice. Neuropeptides 2022; 96:102288. [PMID: 36279616 DOI: 10.1016/j.npep.2022.102288] [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: 05/03/2022] [Revised: 09/12/2022] [Accepted: 09/13/2022] [Indexed: 10/14/2022]
Abstract
Amylin is a peripheral satiation signal polypeptide co-secreted with insulin by pancreatic β-cells in response to nutrient ingestion. Amylin participates in the eating-inhibitory effect and regulates energy metabolism by acting on the central nervous system (CNS). However, the role of amylin in regulating the biosynthesis of steroid hormones, such as testosterone, through the hypothalamic-pituitary-gonadal axis (HPG) remains unexplored. However, only limited evidence is available on the involvement of amylin in steroid synthesis, we hypothesize that amylin regulates testosterone levels via steroidogenesis-related enzymes in the CNS. In this study, we elucidated the effect of intraperitoneal injection of amylin on the protein expression of steroidogenesis-related enzymes, including 3β-hydroxysteroid dehydrogenase (3β-HSD), cytochrome P450 17A1 (CYP17A1), and steroidogenic acute regulatory protein (StAR), and phospho-extracellular signal-regulated kinase (pERK). Additionally, the effect of amylin on testosterone levels in male mice was examined. Our results suggested that 3β-HSD and CYP17A1 neurons were widely expressed in the CNS of male mice, whereas StAR neurons were mainly expressed in the zona incerta (ZI) and locus coeruleus (LC) regions. Intraperitoneal injection of amylin significantly reduced (p < 0.01) the expression of 3β-HSD, CYP17A1, and StAR in ZI and other areas near the third ventricle (3 V) but increased (p < 0.01) pERK expression, brain testosterone levels, serum FSH, serum LH, and decreased (p < 0.01) serum testosterone levels in mice. In conclusion, amylin regulates testosterone levels via steroidogenesis-related enzymes in the central nervous system of male mice.
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Affiliation(s)
- Yujie Chen
- Vocational and Technical College, Inner Mongolia Agricultural University, Baotou 014109, China
| | - Qiang Li
- College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Xiaojing Li
- College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Haodong Liu
- College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Penghui Li
- College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot 010018, China
| | - Rihan Hai
- Vocational and Technical College, Inner Mongolia Agricultural University, Baotou 014109, China
| | - Yongqing Guo
- Vocational and Technical College, Inner Mongolia Agricultural University, Baotou 014109, China
| | - Siwei Wang
- Institute of Cereal and Oil Crops, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang 050000, China; Key Laboratory of Crop Cultivation Physiology and Green Production in Hebei Province, Shijiazhuang 050000, China
| | - Kun Wang
- Institute of Cereal and Oil Crops, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang 050000, China; Key Laboratory of Crop Cultivation Physiology and Green Production in Hebei Province, Shijiazhuang 050000, China
| | - Chenguang Du
- Vocational and Technical College, Inner Mongolia Agricultural University, Baotou 014109, China; College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot 010018, China.
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Mathiesen DS, Lund A, Holst JJ, Knop FK, Lutz TA, Bagger JI. THERAPY OF ENDOCRINE DISEASE: Amylin and calcitonin - physiology and pharmacology. Eur J Endocrinol 2022; 186:R93-R111. [PMID: 35353712 DOI: 10.1530/eje-21-1261] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 03/30/2022] [Indexed: 11/08/2022]
Abstract
Type 2 diabetes is a common manifestation of metabolic dysfunction due to obesity and constitutes a major burden for modern health care systems, in concert with the alarming rise in obesity worldwide. In recent years, several successful pharmacotherapies improving glucose metabolism have emerged and some of these also promote weight loss, thus, ameliorating insulin resistance. However, the progressive nature of type 2 diabetes is not halted by these new anti-diabetic pharmacotherapies. Therefore, novel therapies promoting weight loss further and delaying diabetes progression are needed. Amylin, a beta cell hormone, has satiating properties and also delays gastric emptying and inhibits postprandial glucagon secretion with the net result of reducing postprandial glucose excursions. Amylin acts through the six amylin receptors, which share the core component with the calcitonin receptor. Calcitonin, derived from thyroid C cells, is best known for its role in humane calcium metabolism, where it inhibits osteoclasts and reduces circulating calcium. However, calcitonin, particularly of salmon origin, has also been shown to affect insulin sensitivity, reduce the gastric emptying rate and promote satiation. Preclinical trials with agents targeting the calcitonin receptor and the amylin receptors, show improvements in several parameters of glucose metabolism including insulin sensitivity and some of these agents are currently undergoing clinical trials. Here, we review the physiological and pharmacological effects of amylin and calcitonin and discuss the future potential of amylin and calcitonin-based treatments for patients with type 2 diabetes and obesity.
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Affiliation(s)
- David S Mathiesen
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
| | - Asger Lund
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
- Department of Medicine, Gentofte and Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip K Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
- Department of Medicine, Gentofte and Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, Gentofte, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse-Faculty, University of Zurich, Zurich, Switzerland
| | - Jonatan I Bagger
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
- Department of Medicine, Gentofte and Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, Gentofte, Denmark
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6
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Lutz TA. Creating the amylin story. Appetite 2022; 172:105965. [DOI: 10.1016/j.appet.2022.105965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/28/2022] [Accepted: 02/04/2022] [Indexed: 02/07/2023]
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Mathiesen DS, Lund A, Vilsbøll T, Knop FK, Bagger JI. Amylin and Calcitonin: Potential Therapeutic Strategies to Reduce Body Weight and Liver Fat. Front Endocrinol (Lausanne) 2021; 11:617400. [PMID: 33488526 PMCID: PMC7819850 DOI: 10.3389/fendo.2020.617400] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 11/23/2020] [Indexed: 02/06/2023] Open
Abstract
The hormones amylin and calcitonin interact with receptors within the same family to exert their effects on the human organism. Calcitonin, derived from thyroid C cells, is known for its inhibitory effect on osteoclasts. Calcitonin of mammalian origin promotes insulin sensitivity, while the more potent calcitonin extracted from salmon additionally inhibits gastric emptying, promotes gallbladder relaxation, increases energy expenditure and induces satiety as well as weight loss. Amylin, derived from pancreatic beta cells, regulates plasma glucose by delaying gastric emptying after meal ingestion, and modulates glucagon secretion and central satiety signals in the brain. Thus, both hormones seem to have metabolic effects of relevance in the context of non-alcoholic fatty liver disease (NAFLD) and other metabolic diseases. In rats, studies with dual amylin and calcitonin receptor agonists have demonstrated robust body weight loss, improved glucose tolerance and a decreased deposition of fat in liver tissue beyond what is observed after a body weight loss. The translational aspects of these preclinical data currently remain unknown. Here, we describe the physiology, pathophysiology, and pharmacological effects of amylin and calcitonin and review preclinical and clinical findings alluding to the future potential of amylin and calcitonin-based drugs for the treatment of obesity and NAFLD.
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Affiliation(s)
- David S. Mathiesen
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
| | - Asger Lund
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
| | - Tina Vilsbøll
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
- Steno Diabetes Center Copenhagen, Gentofte, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip K. Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
- Steno Diabetes Center Copenhagen, Gentofte, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jonatan I. Bagger
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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8
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Foll CL, Lutz TA. Systemic and Central Amylin, Amylin Receptor Signaling, and Their Physiological and Pathophysiological Roles in Metabolism. Compr Physiol 2020; 10:811-837. [PMID: 32941692 DOI: 10.1002/cphy.c190034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This article in the Neural and Endocrine Section of Comprehensive Physiology discusses the physiology and pathophysiology of the pancreatic hormone amylin. Shortly after its discovery in 1986, amylin has been shown to reduce food intake as a satiation signal to limit meal size. Amylin also affects food reward, sensitizes the brain to the catabolic actions of leptin, and may also play a prominent role in the development of certain brain areas that are involved in metabolic control. Amylin may act at different sites in the brain in addition to the area postrema (AP) in the caudal hindbrain. In particular, the sensitizing effect of amylin on leptin action may depend on a direct interaction in the hypothalamus. The concept of central pathways mediating amylin action became more complex after the discovery that amylin is also synthesized in certain hypothalamic areas but the interaction between central and peripheral amylin signaling remains currently unexplored. Amylin may also play a dominant pathophysiological role that is associated with the aggregation of monomeric amylin into larger, cytotoxic molecular entities. This aggregation in certain species may contribute to the development of type 2 diabetes mellitus but also cardiovascular disease. Amylin receptor pharmacology is complex because several distinct amylin receptor subtypes have been described, because other neuropeptides [e.g., calcitonin gene-related peptide (CGRP)] can also bind to amylin receptors, and because some components of the functional amylin receptor are also used for other G-protein coupled receptor (GPCR) systems. © 2020 American Physiological Society. Compr Physiol 10:811-837, 2020.
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Affiliation(s)
- Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
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9
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Viral depletion of calcitonin receptors in the area postrema: A proof-of-concept study. Physiol Behav 2020; 223:112992. [PMID: 32497530 DOI: 10.1016/j.physbeh.2020.112992] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 05/06/2020] [Accepted: 05/27/2020] [Indexed: 01/12/2023]
Abstract
The area postrema (AP), located in the caudal hindbrain, is one of the primary binding sites for the endocrine satiation hormone amylin. Amylin is co-secreted with insulin from pancreatic ß-cells and binds to heterodimeric receptors that consist of a calcitonin core receptor (CTR) paired with receptor-activity modifying protein (RAMP) 1 or 3. In this study, we aim to validate a CTR-floxed (CTRfl/fl) mouse model for the functional and site-specific depletion of amylin/CTR signaling in the AP and the nucleus tractus solitarius (NTS). CTRfl/fl mice were injected in the NTS with adeno-associated virus (AAV) containing a green fluorescent protein tag (GFP) and Cre recombinase to create a locally restricted knockout of CTR in the caudal hindbrain. KO mice showed a lack of c-Fos expression, a marker for neuronal activation, in the AP, NTS and LPBN after amylin injection. The effect of amylin and salmon calcitonin (sCT), an amylin receptor agonist, on food intake was blunted in KO mice, confirming a functional reduction of amylin signaling in the hindbrain.
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Zachar G, Montagnese C, Fazekas EA, Kemecsei RG, Papp SM, Dóra F, Renner É, Csillag A, Pogány Á, Dobolyi A. Brain Distribution and Sexually Dimorphic Expression of Amylin in Different Reproductive Stages of the Zebra Finch ( Taeniopygia guttata) Suggest Roles of the Neuropeptide in Song Learning and Social Behaviour. Front Neurosci 2020; 13:1401. [PMID: 32009882 PMCID: PMC6971405 DOI: 10.3389/fnins.2019.01401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 12/12/2019] [Indexed: 11/24/2022] Open
Abstract
The expression of the recently identified neuropeptide, amylin, is restricted in rodents to the postpartum preoptic area and may play a role in the control of parental behaviours and food intake. These processes are substantially different between bird and rodent parents as birds do not lactate but often show biparental care of the offspring. To establish the presence and role of amylin in the bird brain, in the present study, we investigated the distribution of amylin in brains of adult male and female zebra finches in three different reproductive stages (i.e. paired without young, incubating eggs or provisioning nestlings) and in unpaired control birds living in same sex flocks. Amylin mRNA was identified in the hypothalamus of zebra finch by RT-PCR, which was also used to produce probes for in situ hybridisation. Subsequently, in situ hybridisation histochemistry was performed in brain sections, and the labelling signal was quantified and compared between the groups. Amylin showed a much wider brain distribution than that of rodents. A strong and, in some regions, sexually dimorphic label was found in the striatum and several brain regions of the social behavioural network in both males and females. Many regions responsible for the learning of birdsong also contained amylin-positive neurons, and some regions showed sex differences reflecting the fact that vocalisation is sexually dimorphic in the zebra finch: only males sing. Area X (Ar.X), a striatal song centre present only in males, was labelled in paired but not unpaired male. Ar.X, another song centre, the lateral part of the magnocellular nucleus of the anterior nidopallium (lMAN) also contained amylin and had higher amylin label in paired, as opposed to unpaired birds. The wider distribution of amylin in birds as compared to rodents suggests a more general role of amylin in social or other behaviours in avian species than in mammals. Alternatively, parental care in birds may be a more complex behavioural trait involving a wider set of brain regions. The sex differences in song centres, and the changes with reproductive status suggest a participation of amylin in social behaviours and related changes in the singing of males.
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Affiliation(s)
- Gergely Zachar
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Catherine Montagnese
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Emese A Fazekas
- MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Eötvös Loránd University and the Hungarian Academy of Sciences, Budapest, Hungary.,Department of Ethology, Eötvös Loránd University, Budapest, Hungary
| | - Róbert G Kemecsei
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Szilvia M Papp
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Fanni Dóra
- Human Brain Tissue Bank and Microdissection Laboratory, Semmelweis University, Budapest, Hungary
| | - Éva Renner
- Human Brain Tissue Bank and Microdissection Laboratory, Semmelweis University, Budapest, Hungary
| | - András Csillag
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Ákos Pogány
- Department of Ethology, Eötvös Loránd University, Budapest, Hungary
| | - Arpád Dobolyi
- MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Eötvös Loránd University and the Hungarian Academy of Sciences, Budapest, Hungary
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Sonne N, Larsen AT, Andreassen KV, Karsdal MA, Henriksen K. The Dual Amylin and Calcitonin Receptor Agonist, KBP-066, Induces an Equally Potent Weight Loss Across a Broad Dose Range While Higher Doses May Further Improve Insulin Action. J Pharmacol Exp Ther 2020; 373:92-102. [PMID: 31992608 DOI: 10.1124/jpet.119.263723] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 01/21/2020] [Indexed: 12/27/2022] Open
Abstract
Pharmacological treatment with dual amylin and calcitonin receptor agonists (DACRAs) cause significant weight loss and improvement of glucose homeostasis. In this study, the maximally efficacious dose of the novel DACRA, KeyBiosciencePeptide (KBP)-066, was investigated. Two different rat models were used: high-fat diet (HFD)-fed male Sprague-Dawley rats and male Zucker diabetic fatty (ZDF, fa/fa) rats to determine the maximum weight loss and glucose homeostatic effect, respectively. One acute study and one chronic study was performed in HFD rats. Two chronic studies were performed in ZDF rats: a preventive and an interventive. All studies covered a dose range of 5, 50, and 500 µg/kg KBP-066 delivered by subcutaneous injection. Treatment with KBP-066 resulted in a significant weight reduction of 13%-16% and improved glucose tolerance in HFD rats, which was independent of dose concentration. Dosing with 50 and 500 µg/kg led to a transient but significant increase in blood glucose, both in the acute and the chronic study in HFD rats. All doses of KBP-066 significantly improved glucose homeostasis in ZDF rats, both in the preventive and interventive study. Moreover, dosing with 50 and 500 µg/kg preserved insulin secretion to a greater extent than 5 µg/kg when compared with ZDF vehicle rats. Taken together, these results show that maximum weight loss is achieved with 5 µg/kg, which is within the range of previously reported DACRA dosing, whereas increasing dosing concentration to 50 and 500 µg/kg may further improve preservation of insulin secretion compared with 5 µg/kg in diabetic ZDF rats. SIGNIFICANCE STATEMENT: Here we show that KeyBiosciencePeptide (KBP)-066 induces an equally potent body weight loss across a broad dose range in obese rats. However, higher dosing of KBP-066 may improve insulin action in diabetic rats both as preventive and interventive treatment.
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Affiliation(s)
- Nina Sonne
- Nordic Bioscience Biomarkers and Research, Department of Endocrinology, Herlev, Denmark
| | - Anna Thorsø Larsen
- Nordic Bioscience Biomarkers and Research, Department of Endocrinology, Herlev, Denmark
| | - Kim Vietz Andreassen
- Nordic Bioscience Biomarkers and Research, Department of Endocrinology, Herlev, Denmark
| | - Morten Asser Karsdal
- Nordic Bioscience Biomarkers and Research, Department of Endocrinology, Herlev, Denmark
| | - Kim Henriksen
- Nordic Bioscience Biomarkers and Research, Department of Endocrinology, Herlev, Denmark
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12
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Gong M, Wen S, Nguyen T, Wang C, Jin J, Zhou L. Converging Relationships of Obesity and Hyperuricemia with Special Reference to Metabolic Disorders and Plausible Therapeutic Implications. Diabetes Metab Syndr Obes 2020; 13:943-962. [PMID: 32280253 PMCID: PMC7125338 DOI: 10.2147/dmso.s232377] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/09/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Obesity and hyperuricemia mutually influence metabolic syndrome. This study discusses the metabolic relationships between obesity and hyperuricemia in terms of pathophysiology, complications, and treatments. METHODS We searched for preclinical or clinical studies on the pathophysiology, complications, and therapy of obesity and hyperuricemia on the PubMed database. RESULTS In this systemic review, we summarized our searching results on topics of pathophysiology, complications and therapeutic strategy. In pathophysiology, we firstly introduce genetic variations for obesity, hyperuricemia and their relationships by genetic studies. Secondly, we talk about the epigenetic influences on obesity and hyperuricemia. Thirdly, we describe the central metabolic regulation and the role of hyperuricemia. Then, we refer to the character of adipose tissue inflammation and oxidative stress in the obesity and hyperuricemia. In the last part of this topic, we reviewed the critical links of gut microbiota in the obesity and hyperuricemia. In the following part, we review the pathophysiology of major complications in obesity and hyperuricemia including insulin resistance and type 2 diabetes mellitus, chronic kidney disease, cardiovascular diseases, and cancers. Finally, we recapitulate the therapeutic strategies especially the novel pharmaceutic interventions for obesity and hyperuricemia, which concurrently show the mutual metabolic influences between two diseases. CONCLUSION The data reviewed here delineate the metabolic relationships between obesity and hyperuricemia, and provide a comprehensive overview of the therapeutic targets for the management of metabolic syndromes.
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Affiliation(s)
- Min Gong
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai201399, People’s Republic of China
| | - Song Wen
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai201399, People’s Republic of China
| | - Thiquynhnga Nguyen
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai201399, People’s Republic of China
| | - Chaoxun Wang
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai201399, People’s Republic of China
| | - Jianlan Jin
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai201399, People’s Republic of China
| | - Ligang Zhou
- Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai201399, People’s Republic of China
- Correspondence: Ligang Zhou Department of Endocrinology, Shanghai Pudong Hospital, Fudan University, Shanghai201399, ChinaTel +8613611927616 Email
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13
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Boyle CN, Le Foll C. Amylin and Leptin interaction: Role During Pregnancy, Lactation and Neonatal Development. Neuroscience 2019; 447:136-147. [PMID: 31846753 DOI: 10.1016/j.neuroscience.2019.11.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 11/08/2019] [Accepted: 11/21/2019] [Indexed: 01/04/2023]
Abstract
Amylin is co-secreted with insulin by pancreatic β-cells in response to a meal and produced by neurons in discrete hypothalamic brain areas. Leptin is proportionally secreted by the adipose tissue. Both hormones control food intake and energy homeostasis post-weaning in rodents. While amylin's main site of action is located in the area postrema (AP) and leptin's is located in the mediobasal hypothalamus, both hormones can also influence the other's signaling pathway; amylin has been shown enhance hypothalamic leptin signaling, and amylin signaling in the AP may rely on functional leptin receptors to modulate its effects. These two hormones also play major roles during other life periods. During pregnancy, leptin levels rise as a result of an increase in fat depot resulting in gestational leptin-resistance to prepare the maternal body for the metabolic needs during fetal development. The role of amylin is far less studied during pregnancy and lactation, though amylin levels seem to be elevated during pregnancy relative to insulin. Whether amylin and leptin interact during pregnancy and lactation remains to be assessed. Lastly, during brain development, amylin and leptin are major regulators of cell birth during embryogenesis and act as neurotrophic factors in the neonatal period. This review will highlight the role of amylin and leptin, and their possible interaction, during these dynamic time periods of pregnancy, lactation, and early development.
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Affiliation(s)
- Christina N Boyle
- Institute of Veterinary Physiology, University of Zurich, Winterthurerstrasse 260, 8057 Zurich, Switzerland.
| | - Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Winterthurerstrasse 260, 8057 Zurich, Switzerland.
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14
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Nie T, Zhang S, Vazhoor Amarsingh G, Liu H, McCann MJ, Cooper GJS. Altered metabolic gene expression in the brain of a triprolyl-human amylin transgenic mouse model of type 2 diabetes. Sci Rep 2019; 9:14588. [PMID: 31601900 PMCID: PMC6787337 DOI: 10.1038/s41598-019-51088-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 09/24/2019] [Indexed: 12/12/2022] Open
Abstract
Type 2 diabetes mellitus is a major health concern worldwide; however, the molecular mechanism underlying its development is poorly understood. The hormone amylin is postulated to be involved, as human amylin forms amyloid in the pancreases of diabetic patients, and oligomers have been shown to be cytotoxic to β-cells. As rodent amylin is non-amyloidogenic, mice expressing human amylin have been developed to investigate this hypothesis. However, it is not possible to differentiate the effects of amylin overexpression from β-cell loss in these models. We have developed transgenic mice that overexpress [25, 28, 29 triprolyl]human amylin, a non-amyloidogenic variant of amylin, designated the Line 44 model. This model allows us to investigate the effects of chronic overexpression of non-cytotoxic amylin. We characterised this model and found it developed obesity, hyperglycaemia and hyperinsulinaemia. This phenotype was associated with alterations in the expression of genes involved in the amylin, insulin and leptin signalling pathways within the brain. This included genes such as c-Fos (a marker of amylin activation); Socs3 (a leptin inhibitor); and Cart, Pomc and Npy (neuropeptides that control appetite). We also examined Socs3 protein expression and phosphorylated Stat3 to determine if changes at the mRNA level would be reflected at the protein level.
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Affiliation(s)
- Tina Nie
- School of Biological Sciences, Faculty of Science, the University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Shaoping Zhang
- School of Biological Sciences, Faculty of Science, the University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.,The Maurice Wilkins Centre for Molecular Biodiscovery, Faculty of Science, the University of Auckland, Auckland, New Zealand
| | - Greeshma Vazhoor Amarsingh
- School of Biological Sciences, Faculty of Science, the University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Hong Liu
- School of Biological Sciences, Faculty of Science, the University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Mark J McCann
- Food Nutrition & Health Team, AgResearch Ltd, Grasslands Research Centre, Palmerston North, 4442, New Zealand
| | - Garth J S Cooper
- School of Biological Sciences, Faculty of Science, the University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand. .,The Maurice Wilkins Centre for Molecular Biodiscovery, Faculty of Science, the University of Auckland, Auckland, New Zealand. .,Centre for Advanced Discovery and Experimental Therapeutics, Division of Cardiovascular Sciences, Faculty of Biology Medicine & Health, School of Medical Sciences, the University of Manchester, Manchester, M13 9NT, United Kingdom.
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15
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Kalafateli AL, Vallöf D, Colombo G, Lorrai I, Maccioni P, Jerlhag E. An amylin analogue attenuates alcohol-related behaviours in various animal models of alcohol use disorder. Neuropsychopharmacology 2019; 44:1093-1102. [PMID: 30710109 PMCID: PMC6461824 DOI: 10.1038/s41386-019-0323-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 01/15/2019] [Accepted: 01/16/2019] [Indexed: 12/15/2022]
Abstract
Recent findings have identified salmon calcitonin (sCT), an amylin receptor agonist and analogue of endogenous amylin, as a potential regulator of alcohol-induced activation of the mesolimbic dopamine system and alcohol consumption. Providing that the role of amylin signalling in alcohol-related behaviours remains unknown, the present experiments investigate the effect of sCT on these behaviours and the mechanisms involved. We showed that repeated sCT administration decreased alcohol and food intake in outbred rats. Moreover, single administration of the potent amylin receptor antagonist, AC187, increased short-term alcohol intake in outbred alcohol-consuming rats, but did not affect food intake. Acute administration of sCT prevented relapse-like drinking in the "alcohol deprivation effect" model in outbred alcohol-experienced rats. Additionally, acute sCT administration reduced operant oral alcohol self-administration (under the fixed ratio 4 schedule of reinforcement) in selectively bred Sardinian alcohol-preferring rats, while it did not alter operant self-administration (under the progressive ratio schedule of reinforcement) of a highly palatable chocolate-flavoured beverage in outbred rats. Lastly, we identified differential amylin receptor expression in high compared to low alcohol-consuming rats, as reflected by decreased calcitonin receptor and increased receptor activity modifying protein 1 expression in the nucleus accumbens (NAc) of high consumers. Collectively, our data suggest that amylin signalling, especially in the NAc, may contribute to reduction of various alcohol-related behaviours.
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Affiliation(s)
- Aimilia Lydia Kalafateli
- 0000 0000 9919 9582grid.8761.8Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Daniel Vallöf
- 0000 0000 9919 9582grid.8761.8Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Giancarlo Colombo
- 0000 0001 1940 4177grid.5326.2Neuroscience Institute, Section of Cagliari, National Research Council of Italy, Monserrato, CA Italy
| | - Irene Lorrai
- 0000 0001 1940 4177grid.5326.2Neuroscience Institute, Section of Cagliari, National Research Council of Italy, Monserrato, CA Italy
| | - Paola Maccioni
- 0000 0001 1940 4177grid.5326.2Neuroscience Institute, Section of Cagliari, National Research Council of Italy, Monserrato, CA Italy
| | - Elisabet Jerlhag
- Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
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16
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Kalafateli AL, Vallöf D, Jerlhag E. Activation of amylin receptors attenuates alcohol-mediated behaviours in rodents. Addict Biol 2019; 24:388-402. [PMID: 29405517 PMCID: PMC6585842 DOI: 10.1111/adb.12603] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 12/14/2017] [Accepted: 01/05/2018] [Indexed: 02/06/2023]
Abstract
Alcohol expresses its reinforcing properties by activating areas of the mesolimbic dopamine system, which consists of dopaminergic neurons projecting from the ventral tegmental area to the nucleus accumbens. The findings that reward induced by food and addictive drugs involve common mechanisms raise the possibility that gut-brain hormones, which control appetite, such as amylin, could be involved in reward regulation. Amylin decreases food intake, and despite its implication in the regulation of natural rewards, tenuous evidence support amylinergic mediation of artificial rewards, such as alcohol. Therefore, the present experiments were designed to investigate the effect of salmon calcitonin (sCT), an amylin receptor agonist and analogue of endogenous amylin, on various alcohol-related behaviours in rodents. We showed that acute sCT administration attenuated the established effects of alcohol on the mesolimbic dopamine system, particularly alcohol-induced locomotor stimulation and accumbal dopamine release. Using the conditioned place preference model, we demonstrated that repeated sCT administration prevented the expression of alcohol's rewarding properties and that acute sCT administration blocked the reward-dependent memory consolidation. In addition, sCT pre-treatment attenuated alcohol intake in low alcohol-consuming rats, with a more evident decrease in high alcohol consumers in the intermittent alcohol access model. Lastly, sCT did not alter peanut butter intake, blood alcohol concentration and plasma corticosterone levels in mice. Taken together, the present data support that amylin signalling is involved in the expression of alcohol reinforcement and that amylin receptor agonists could be considered for the treatment of alcohol use disorder in humans.
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Affiliation(s)
- Aimilia Lydia Kalafateli
- Department of Pharmacology, Institute of Neuroscience and PhysiologyThe Sahlgrenska Academy at the University of Gothenburg Gothenburg Sweden
| | - Daniel Vallöf
- Department of Pharmacology, Institute of Neuroscience and PhysiologyThe Sahlgrenska Academy at the University of Gothenburg Gothenburg Sweden
| | - Elisabet Jerlhag
- Department of Pharmacology, Institute of Neuroscience and PhysiologyThe Sahlgrenska Academy at the University of Gothenburg Gothenburg Sweden
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17
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Maniscalco JW, Rinaman L. Vagal Interoceptive Modulation of Motivated Behavior. Physiology (Bethesda) 2019; 33:151-167. [PMID: 29412062 DOI: 10.1152/physiol.00036.2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In addition to regulating the ingestion and digestion of food, sensory feedback from gut to brain modifies emotional state and motivated behavior by subconsciously shaping cognitive and affective responses to events that bias behavioral choice. This focused review highlights evidence that gut-derived signals impact motivated behavior by engaging vagal afferents and central neural circuits that generally serve to limit or terminate goal-directed approach behaviors, and to initiate or maintain behavioral avoidance.
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Affiliation(s)
- J W Maniscalco
- Department of Psychology, University of Illinois at Chicago, Chicago, Illionois
| | - L Rinaman
- Department of Psychology, Florida State University , Tallahassee, Florida
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18
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Almeida LS, Castro‐Lopes JM, Neto FL, Potes CS. Amylin, a peptide expressed by nociceptors, modulates chronic neuropathic pain. Eur J Pain 2019; 23:784-799. [DOI: 10.1002/ejp.1347] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/05/2018] [Accepted: 11/27/2018] [Indexed: 12/18/2022]
Affiliation(s)
- Lígia Sofia Almeida
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto Porto Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto Porto Portugal
- Departamento de Biomedicina – Unidade de Biologia Experimental, Faculdade de Medicina Universidade do Porto Porto Portugal
| | - José Manuel Castro‐Lopes
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto Porto Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto Porto Portugal
- Departamento de Biomedicina – Unidade de Biologia Experimental, Faculdade de Medicina Universidade do Porto Porto Portugal
| | - Fani Lourença Neto
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto Porto Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto Porto Portugal
- Departamento de Biomedicina – Unidade de Biologia Experimental, Faculdade de Medicina Universidade do Porto Porto Portugal
| | - Catarina Soares Potes
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto Porto Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Universidade do Porto Porto Portugal
- Departamento de Biomedicina – Unidade de Biologia Experimental, Faculdade de Medicina Universidade do Porto Porto Portugal
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19
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Jerlhag E. Gut-brain axis and addictive disorders: A review with focus on alcohol and drugs of abuse. Pharmacol Ther 2018; 196:1-14. [PMID: 30439457 DOI: 10.1016/j.pharmthera.2018.11.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Due to the limited efficacy of existing medications for addictive disorders including alcohol use disorder (AUD), the need for additional medications is substantial. Potential new medications for addiction can be identified through investigation of the neurochemical substrates mediating the ability of drugs of abuse such as alcohol to activate the mesolimbic dopamine system. Interestingly, recent studies implicate neuropeptides of the gut-brain axis as modulators of reward and addiction processes. The present review therefore summarizes the current studies investigating the ability of the gut-brain peptides ghrelin, glucagon-like peptide-1 (GLP-1), amylin and neuromedin U (NMU) to modulate alcohol- and drug-related behaviors in rodents and humans. Extensive literature demonstrates that ghrelin, the only known orexigenic neuropeptide to date, enhances reward as well as the intake of alcohol, and other drugs of abuse, while ghrelin receptor antagonism has the opposite effects. On the other hand, the anorexigenic peptides GLP-1, amylin and NMU independently inhibits reward from alcohol and drugs of abuse in rodents. Collectively, these rodent and human studies imply that central ghrelin, GLP-1, amylin and NMU signaling may contribute to addiction processes. Therefore, the need for randomized clinical trials investigating the effects of agents targeting these aforementioned systems on drug/alcohol use is substantial.
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Affiliation(s)
- Elisabet Jerlhag
- Institute of Neuroscience and Physiology, Department of Pharmacology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
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20
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Bower RL, Yule L, Rees TA, Deganutti G, Hendrikse ER, Harris PWR, Kowalczyk R, Ridgway Z, Wong AG, Swierkula K, Raleigh DP, Pioszak AA, Brimble MA, Reynolds CA, Walker CS, Hay DL. Molecular Signature for Receptor Engagement in the Metabolic Peptide Hormone Amylin. ACS Pharmacol Transl Sci 2018; 1:32-49. [PMID: 32219203 DOI: 10.1021/acsptsci.8b00002] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Indexed: 11/30/2022]
Abstract
The pancreatic peptide hormone, amylin, plays a critical role in the control of appetite, and synergizes with other key metabolic hormones such as glucagon-like peptide 1 (GLP-1). There is opportunity to develop potent and long-acting analogues of amylin or hybrids between these and GLP-1 mimetics for treating obesity. To achieve this, interrogation of how the 37 amino acid amylin peptide engages with its complex receptor system is required. We synthesized an extensive library of peptides to profile the human amylin sequence, determining the role of its disulfide loop, amidated C-terminus and receptor "capture" and "activation" regions in receptor signaling. We profiled four signaling pathways with different ligands at multiple receptor subtypes, in addition to exploring selectivity determinants between related receptors. Distinct roles for peptide subregions in receptor binding and activation were identified, resulting in peptides with greater activity than the native sequence. Enhanced peptide activity was preserved in the brainstem, the major biological target for amylin. Interpretation of our data using full-length active receptor models supported by molecular dynamics, metadynamics, and supervised molecular dynamics simulations guided the synthesis of a potent dual agonist of GLP-1 and amylin receptors. The data offer new insights into the function of peptide amidation, how allostery drives peptide-receptor interactions, and provide a valuable resource for the development of novel amylin agonists for treating diabetes and obesity.
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Affiliation(s)
- Rebekah L Bower
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Lauren Yule
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Tayla A Rees
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Giuseppe Deganutti
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K
| | - Erica R Hendrikse
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Paul W R Harris
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Renata Kowalczyk
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Zachary Ridgway
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Amy G Wong
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Katarzyna Swierkula
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K
| | - Daniel P Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States.,Department of Structural and Molecular Biology, University College London, London WC1E 6BT, U.K
| | - Augen A Pioszak
- Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, United States
| | - Margaret A Brimble
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Christopher A Reynolds
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K
| | - Christopher S Walker
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Debbie L Hay
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
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21
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Reiner DJ, Mietlicki-Baase EG, Olivos DR, McGrath LE, Zimmer DJ, Koch-Laskowski K, Krawczyk J, Turner CA, Noble EE, Hahn JD, Schmidt HD, Kanoski SE, Hayes MR. Amylin Acts in the Lateral Dorsal Tegmental Nucleus to Regulate Energy Balance Through Gamma-Aminobutyric Acid Signaling. Biol Psychiatry 2017; 82:828-838. [PMID: 28237459 PMCID: PMC5503810 DOI: 10.1016/j.biopsych.2016.12.028] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 12/13/2016] [Accepted: 12/28/2016] [Indexed: 12/11/2022]
Abstract
BACKGROUND The pancreatic- and brain-derived hormone amylin promotes negative energy balance and is receiving increasing attention as a promising obesity therapeutic. However, the neurobiological substrates mediating amylin's effects are not fully characterized. We postulated that amylin acts in the lateral dorsal tegmental nucleus (LDTg), an understudied neural processing hub for reward and homeostatic feeding signals. METHODS We used immunohistochemical and quantitative polymerase chain reaction analyses to examine expression of the amylin receptor complex in rat LDTg tissue. Behavioral experiments were performed to examine the mechanisms underlying the hypophagic effects of amylin receptor activation in the LDTg. RESULTS Immunohistochemical and quantitative polymerase chain reaction analyses show expression of the amylin receptor complex in the LDTg. Activation of LDTg amylin receptors by the agonist salmon calcitonin dose-dependently reduces body weight, food intake, and motivated feeding behaviors. Acute pharmacological studies and longer-term adeno-associated viral knockdown experiments indicate that LDTg amylin receptor signaling is physiologically and potentially preclinically relevant for energy balance control. Finally, immunohistochemical data indicate that LDTg amylin receptors are expressed on gamma-aminobutyric acidergic neurons, and behavioral results suggest that local gamma-aminobutyric acid receptor signaling mediates the hypophagia after LDTg amylin receptor activation. CONCLUSIONS These findings identify the LDTg as a novel nucleus with therapeutic potential in mediating amylin's effects on energy balance through gamma-aminobutyric acid receptor signaling.
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Affiliation(s)
- David J Reiner
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Elizabeth G Mietlicki-Baase
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Diana R Olivos
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Lauren E McGrath
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Derek J Zimmer
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Kieran Koch-Laskowski
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Joanna Krawczyk
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Christopher A Turner
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, Philadelphia, Pennsylvania; Department of Biobehavioral Health Sciences, School of Nursing, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Emily E Noble
- Department of Biological Sciences, Human and Evolutionary Biology Section, Los Angeles, California
| | - Joel D Hahn
- Neurobiology Section, University of Southern California, Los Angeles, California
| | - Heath D Schmidt
- Department of Biobehavioral Health Sciences, School of Nursing, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Scott E Kanoski
- Department of Biological Sciences, Human and Evolutionary Biology Section, Los Angeles, California
| | - Matthew R Hayes
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, Philadelphia, Pennsylvania.
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22
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Boyle CN, Lutz TA, Le Foll C. Amylin - Its role in the homeostatic and hedonic control of eating and recent developments of amylin analogs to treat obesity. Mol Metab 2017; 8:203-210. [PMID: 29203236 PMCID: PMC5985014 DOI: 10.1016/j.molmet.2017.11.009] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/13/2017] [Accepted: 11/17/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Amylin is a pancreatic β-cell hormone that produces effects in several different organ systems. One of its best-characterized effects is the reduction in eating and body weight seen in preclinical and clinical studies. Amylin activates specific receptors, a portion of which it shares with calcitonin gene-related peptide (CGRP). Amylin's role in the control of energy metabolism relates to its satiating effect, but recent data indicate that amylin may also affect hedonic aspects in the control of eating, including a reduction of the rewarding value of food. Recently, several amylin-based peptides have been characterized. Pramlintide (Symlin®) is currently the only one being used clinically to treat type 1 and type 2 diabetes. However other amylin analogs with improved pharmacokinetic properties are being considered as anti-obesity treatment strategies. Several other studies in obesity have shown that amylin agonists could also be useful for weight loss, especially in combination with other agents. SCOPE OF REVIEW This review will briefly summarize amylin physiology and pharmacology and then focus on amylin's role in food reward and the effects of amylin analogs in pre-clinical testing for anti-obesity drugs. CONCLUSION We propose here that the effects of amylin may be homeostatic and hedonic in nature.
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Affiliation(s)
- Christina Neuner Boyle
- Institute of Veterinary Physiology and Zurich Centre for Integrative Human Physiology, University of Zurich, Switzerland
| | - Thomas Alexander Lutz
- Institute of Veterinary Physiology and Zurich Centre for Integrative Human Physiology, University of Zurich, Switzerland.
| | - Christelle Le Foll
- Institute of Veterinary Physiology and Zurich Centre for Integrative Human Physiology, University of Zurich, Switzerland
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Bucci D, Busceti CL, Calierno MT, Di Pietro P, Madonna M, Biagioni F, Ryskalin L, Limanaqi F, Nicoletti F, Fornai F. Systematic Morphometry of Catecholamine Nuclei in the Brainstem. Front Neuroanat 2017; 11:98. [PMID: 29163071 PMCID: PMC5666292 DOI: 10.3389/fnana.2017.00098] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 10/17/2017] [Indexed: 01/08/2023] Open
Abstract
Catecholamine nuclei within the brainstem reticular formation (RF) play a pivotal role in a variety of brain functions. However, a systematic characterization of these nuclei in the very same experimental conditions is missing so far. Tyrosine hydroxylase (TH) immune-positive cells of the brainstem correspond to dopamine (DA)-, norepinephrine (NE)-, and epinephrine (E)-containing cells. Here, we report a systematic count of TH-positive neurons in the RF of the mouse brainstem by using stereological morphometry. All these nuclei were analyzed for anatomical localization, rostro-caudal extension, volume, neuron number, neuron density, and mean neuronal area for each nucleus. The present data apart from inherent informative value wish to represent a reference for neuronal mapping in those studies investigating the functional anatomy of the brainstem RF. These include: the sleep-wake cycle, movement control, muscle tone modulation, mood control, novelty orienting stimuli, attention, archaic responses to internal and external stressful stimuli, anxiety, breathing, blood pressure, and innumerable activities modulated by the archaic iso-dendritic hard core of the brainstem RF. Most TH-immune-positive cells fill the lateral part of the RF, which indeed possesses a high catecholamine content. A few nuclei are medial, although conventional nosography considers all these nuclei as part of the lateral column of the RF. Despite the key role of these nuclei in psychiatric and neurological disorders, only a few of them aspired a great attention in biomedical investigation, while most of them remain largely obscure although intense research is currently in progress. A simultaneous description of all these nuclei is not simply key to comprehend the variety of brainstem catecholamine reticular neurons, but probably represents an intrinsically key base for understanding brain physiology and physiopathology.
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Affiliation(s)
- Domenico Bucci
- Istituto Neurologico Mediterraneo (IRCCS), Neuromed, Pozzilli, Italy
| | - Carla L Busceti
- Istituto Neurologico Mediterraneo (IRCCS), Neuromed, Pozzilli, Italy
| | - Maria T Calierno
- Istituto Neurologico Mediterraneo (IRCCS), Neuromed, Pozzilli, Italy
| | - Paola Di Pietro
- Istituto Neurologico Mediterraneo (IRCCS), Neuromed, Pozzilli, Italy
| | - Michele Madonna
- Istituto Neurologico Mediterraneo (IRCCS), Neuromed, Pozzilli, Italy
| | | | - Larisa Ryskalin
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Fiona Limanaqi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Ferdinando Nicoletti
- Istituto Neurologico Mediterraneo (IRCCS), Neuromed, Pozzilli, Italy.,Department of Physiology and Pharmacology, Sapienza Università di Roma, Rome, Italy
| | - Francesco Fornai
- Istituto Neurologico Mediterraneo (IRCCS), Neuromed, Pozzilli, Italy.,Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
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Amylin and its G-protein-coupled receptor: A probable pathological process and drug target for Alzheimer's disease. Neuroscience 2017; 356:44-51. [PMID: 28528968 DOI: 10.1016/j.neuroscience.2017.05.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/11/2017] [Accepted: 05/12/2017] [Indexed: 12/31/2022]
Abstract
G-protein-coupled receptors (GPCRs) are shown to be involved in Alzheimer's disease (AD) pathogenesis. However, because GPCRs include a large family of membrane receptors, it is unclear which specific GPCR or pathway with rational ligands can become effective therapeutic targets for AD. Amylin receptor (AmR) is a GPCR that mediates several activities, such as improving glucose metabolism, relaxing cerebrovascular structure, modulating inflammatory reactions and potentially enhancing neural regeneration. Recent studies show that peripheral treatments with amylin or its clinical analog, pramlintide, reduced several components of AD pathology, including amyloid plaques, tauopathy, neuroinflammation and other components in the brain, corresponding with improved learning and memory in AD mouse models. Because amylin shares a similar secondary structure with amyloid-β peptide (Aβ), I propose that the AmR/GPCR pathway is disturbed by a large amount of Aβ in the AD brain, leading to tau phosphorylation, neuroinflammation and neuronal death in the pathological cascade. Amylin-type peptides, readily crossing the blood-brain barrier (BBB), are the rational ligands to enhance this GPCR pathway and may exhibit utility as novel therapeutic agents for treating AD.
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25
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Senzacqua M, Severi I, Perugini J, Acciarini S, Cinti S, Giordano A. Action of Administered Ciliary Neurotrophic Factor on the Mouse Dorsal Vagal Complex. Front Neurosci 2016; 10:289. [PMID: 27445662 PMCID: PMC4921504 DOI: 10.3389/fnins.2016.00289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 06/10/2016] [Indexed: 12/13/2022] Open
Abstract
Ciliary neurotrophic factor (CNTF) induces weight loss in obese rodents and humans through activation of the hypothalamic Jak-STAT (Janus kinase-signal transducer and activator of transcription) signaling pathway. Here, we tested the hypothesis that CNTF also affects the brainstem centers involved in feeding and energy balance regulation. To this end, wild-type and leptin-deficient (ob/ob and db/db) obese mice were acutely treated with intraperitoneal recombinant CNTF. Coronal brainstem sections were processed for immunohistochemical detection of STAT3, STAT1, STAT5 phosphorylation and c-Fos. In wild-type mice, CNTF treatment for 45 min induced STAT3, STAT1, and STAT5 phosphorylation in neurons as well as glial cells of the area postrema; here, the majority of CNTF-responsive cells activated multiple STAT isoforms, and a significant proportion of CNTF-responsive glial cells bore the immaturity and plasticity markers nestin and vimentin. After 120 min CNTF treatment, c-Fos expression was intense in glial cells and weak in neurons of the area postrema, it was intense in several neurons of the rostral and caudal solitary tract nucleus (NTS), and weak in some cholinergic neurons of the dorsal motor nucleus of the vagus. In the ob/ob and db/db mice, Jak-STAT activation and c-Fos expression were similar to those induced in wild-type mouse brainstem. Treatment with CNTF (120 min, to induce c-Fos expression) and leptin (25 min, to induce STAT3 phosphorylation) demonstrated the co-localization of the two transcription factors in a small neuron population in the caudal NTS portion. Finally, weak immunohistochemical CNTF staining, detected in funiculus separans, and meningeal glial cells, matched the modest amount of CNTF found by RT-qPCR in micropunched area postrema tissue, which in contrast exhibited a very high amount of CNTF receptor. Collectively, the present findings show that the area postrema and the NTS exhibit high, distinctive responsiveness to circulating exogenous and, probably, endogenous CNTF.
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Affiliation(s)
- Martina Senzacqua
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche Ancona, Italy
| | - Ilenia Severi
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche Ancona, Italy
| | - Jessica Perugini
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche Ancona, Italy
| | - Samantha Acciarini
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche Ancona, Italy
| | - Saverio Cinti
- Department of Experimental and Clinical Medicine, Università Politecnica delle MarcheAncona, Italy; Center of Obesity, Università Politecnica delle Marche-United HospitalsAncona, Italy
| | - Antonio Giordano
- Department of Experimental and Clinical Medicine, Università Politecnica delle Marche Ancona, Italy
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26
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Liu Y, Huang Y, Liu T, Wu H, Cui H, Gautron L. Lipopolysacharide Rapidly and Completely Suppresses AgRP Neuron-Mediated Food Intake in Male Mice. Endocrinology 2016; 157:2380-92. [PMID: 27111742 PMCID: PMC4891783 DOI: 10.1210/en.2015-2081] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Although Agouti-related peptide (AgRP) neurons play a key role in the regulation of food intake, their contribution to the anorexia caused by proinflammatory insults has yet to be identified. Using a combination of neuroanatomical and pharmacogenetics experiments, this study sought to investigate the importance of AgRP neurons and downstream targets in the anorexia caused by the peripheral administration of a moderate dose of lipopolysaccharide (LPS) (100 μg/kg, ip). First, in the C57/Bl6 mouse, we demonstrated that LPS induced c-fos in select AgRP-innervated brain sites involved in feeding but not in any arcuate proopiomelanocortin neurons. Double immunohistochemistry further showed that LPS selectively induced c-Fos in a large subset of melanocortin 4 receptor-expressing neurons in the lateral parabrachial nucleus. Secondly, we used pharmacogenetics to stimulate the activity of AgRP neurons during the course of LPS-induced anorexia. In AgRP-Cre mice expressing the designer receptor hM3Dq-Gq only in AgRP neurons, the administration of the designer drug clozapine-N-oxide (CNO) induced robust food intake. Strikingly, CNO-mediated food intake was rapidly and completely blunted by the coadministration of LPS. Neuroanatomical experiments further indicated that LPS did not interfere with the ability of CNO to stimulate c-Fos in AgRP neurons. In summary, our findings combined together support the view that the stimulation of select AgRP-innervated brain sites and target neurons, rather than the inhibition of AgRP neurons themselves, is likely to contribute to the rapid suppression of food intake observed during acute bacterial endotoxemia.
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Affiliation(s)
- Yang Liu
- Division of Hypothalamic Research and Department of Internal Medicine (Y.L., Y.H., T.L., L.G.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Orthopedics (Y.L., H.W.), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China 430030; and Department of Pharmacology (H.C.), Center for Hypertension Research, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242
| | - Ying Huang
- Division of Hypothalamic Research and Department of Internal Medicine (Y.L., Y.H., T.L., L.G.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Orthopedics (Y.L., H.W.), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China 430030; and Department of Pharmacology (H.C.), Center for Hypertension Research, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242
| | - Tiemin Liu
- Division of Hypothalamic Research and Department of Internal Medicine (Y.L., Y.H., T.L., L.G.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Orthopedics (Y.L., H.W.), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China 430030; and Department of Pharmacology (H.C.), Center for Hypertension Research, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242
| | - Hua Wu
- Division of Hypothalamic Research and Department of Internal Medicine (Y.L., Y.H., T.L., L.G.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Orthopedics (Y.L., H.W.), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China 430030; and Department of Pharmacology (H.C.), Center for Hypertension Research, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242
| | - Huxing Cui
- Division of Hypothalamic Research and Department of Internal Medicine (Y.L., Y.H., T.L., L.G.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Orthopedics (Y.L., H.W.), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China 430030; and Department of Pharmacology (H.C.), Center for Hypertension Research, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242
| | - Laurent Gautron
- Division of Hypothalamic Research and Department of Internal Medicine (Y.L., Y.H., T.L., L.G.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390; Department of Orthopedics (Y.L., H.W.), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China 430030; and Department of Pharmacology (H.C.), Center for Hypertension Research, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Carver College of Medicine, Iowa City, Iowa 52242
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27
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Liberini CG, Boyle CN, Cifani C, Venniro M, Hope BT, Lutz TA. Amylin receptor components and the leptin receptor are co-expressed in single rat area postrema neurons. Eur J Neurosci 2016; 43:653-61. [PMID: 26750109 PMCID: PMC10704335 DOI: 10.1111/ejn.13163] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 12/17/2015] [Accepted: 12/22/2015] [Indexed: 12/16/2023]
Abstract
Amylin is a pancreatic β-cell hormone that acts as a satiating signal to inhibit food intake by binding to amylin receptors (AMYs) and activating a specific neuronal population in the area postrema (AP). AMYs are heterodimers that include a calcitonin receptor (CTR) subunit [CTR isoform a or b (CTRa or CTRb)] and a member of the receptor activity-modifying proteins (RAMPs). Here, we used single-cell quantitative polymerase chain reaction to assess co-expression of AMY subunits in AP neurons from rats that were injected with amylin or vehicle. Because amylin interacts synergistically with the adipokine leptin to reduce body weight, we also assessed the co-expression of AMY and the leptin receptor isoform b (LepRb) in amylin-activated AP neurons. Single cells were collected from Wistar rats and from transgenic Fos-GFP rats that express green fluorescent protein (GFP) under the control of the Fos promoter. We found that the mRNAs of CTRa, RAMP1, RAMP2 and RAMP3 were all co-expressed in single AP neurons. Moreover, most of the CTRa+ cells co-expressed more than one of the RAMPs. Amylin down-regulated RAMP1 and RAMP3 but not CTR mRNAs in AMY+ neurons, suggesting a possible negative feedback mechanism of amylin at its own primary receptors. Interestingly, amylin up-regulated RAMP2 mRNA. We also found that a high percentage of single cells that co-expressed all components of a functional AMY expressed LepRb mRNA. Thus, single AP cells expressed both AMY and LepRb, which formed a population of first-order neurons that presumably can be directly activated by amylin and, at least in part, also by leptin.
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Affiliation(s)
- Claudia G. Liberini
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich (UZH), Zurich, Switzerland
- Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- Zurich Centre for Clinical Studies, Vetsuisse Faculty University of Zurich, Zurich, Switzerland
| | - Christina Neuner Boyle
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich (UZH), Zurich, Switzerland
| | - Carlo Cifani
- School of Pharmacy, Pharmacology Unit, University of Camerino, Italy
- Intramural Research Program, National Institutes of Health/National Institute on Drug Abuse, Baltimore, Maryland 21224
| | - Marco Venniro
- Intramural Research Program, National Institutes of Health/National Institute on Drug Abuse, Baltimore, Maryland 21224
| | - Bruce T. Hope
- Intramural Research Program, National Institutes of Health/National Institute on Drug Abuse, Baltimore, Maryland 21224
| | - Thomas A. Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich (UZH), Zurich, Switzerland
- Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
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28
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Dunn-Meynell AA, Le Foll C, Johnson MD, Lutz TA, Hayes MR, Levin BE. Endogenous VMH amylin signaling is required for full leptin signaling and protection from diet-induced obesity. Am J Physiol Regul Integr Comp Physiol 2016; 310:R355-65. [PMID: 26676252 PMCID: PMC4868368 DOI: 10.1152/ajpregu.00462.2015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 12/10/2015] [Indexed: 12/29/2022]
Abstract
Amylin enhances arcuate (ARC) and ventromedial (VMN) hypothalamic nuclei leptin signaling and synergistically reduces food intake and body weight in selectively bred diet-induced obese (DIO) rats. Since DIO (125)I-amylin dorsomedial nucleus-dorsomedial VMN binding was reduced, we postulated that this contributed to DIO ventromedial hypothalamus (VMH) leptin resistance, and that impairing VMH (ARC + VMN) calcitonin receptor (CTR)-mediated signaling by injecting adeno-associated virus (AAV) expressing a short hairpin portion of the CTR mRNA would predispose diet-resistant (DR) rats to obesity on high-fat (45%) diet (HFD). Depleting VMH CTR by 80-90% in 4-wk-old male DR rats reduced their ARC and VMN (125)I-labeled leptin binding by 57 and 51%, respectively, and VMN leptin-induced phospho-signal transducer and activator of transcription 3-positive neurons by 59% vs. AAV control rats. After 6 wk on chow, VMH CTR-depleted DR rats ate and gained the equivalent amount of food and weight but had 18% heavier fat pads (relative to carcass weight), 144% higher leptin levels, and were insulin resistant compared with control AAV DR rats. After 6 wk more on HFD, VMH CTR-depleted DR rats ate the same amount but gained 28% more weight, had 60% more carcass fat, 254% higher leptin levels, and 132% higher insulin areas under the curve during an oral glucose tolerance test than control DR rats. Therefore, impairing endogenous VMH CTR-mediated signaling reduced leptin signaling and caused DR rats to become more obese and insulin resistant, both on chow and HFD. These results suggest that endogenous VMH amylin signaling is required for full leptin signaling and protection from HFD-induced obesity.
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Affiliation(s)
| | - Christelle Le Foll
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Miranda D Johnson
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland
| | - Matthew R Hayes
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Barry E Levin
- Neurology Service, Veterans Administration Medical Center, East Orange, New Jersey; Department of Neurology, Rutgers, New Jersey Medical School, Newark, New Jersey
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29
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Hay DL, Chen S, Lutz TA, Parkes DG, Roth JD. Amylin: Pharmacology, Physiology, and Clinical Potential. Pharmacol Rev 2016; 67:564-600. [PMID: 26071095 DOI: 10.1124/pr.115.010629] [Citation(s) in RCA: 231] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amylin is a pancreatic β-cell hormone that produces effects in several different organ systems. Here, we review the literature in rodents and in humans on amylin research since its discovery as a hormone about 25 years ago. Amylin is a 37-amino-acid peptide that activates its specific receptors, which are multisubunit G protein-coupled receptors resulting from the coexpression of a core receptor protein with receptor activity-modifying proteins, resulting in multiple receptor subtypes. Amylin's major role is as a glucoregulatory hormone, and it is an important regulator of energy metabolism in health and disease. Other amylin actions have also been reported, such as on the cardiovascular system or on bone. Amylin acts principally in the circumventricular organs of the central nervous system and functionally interacts with other metabolically active hormones such as cholecystokinin, leptin, and estradiol. The amylin-based peptide, pramlintide, is used clinically to treat type 1 and type 2 diabetes. Clinical studies in obesity have shown that amylin agonists could also be useful for weight loss, especially in combination with other agents.
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Affiliation(s)
- Debbie L Hay
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - Steve Chen
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - Thomas A Lutz
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - David G Parkes
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
| | - Jonathan D Roth
- School of Biological Sciences, Maurice Wilkins Centre for Molecular Biodiscovery and Centre for Brain Research, University of Auckland, Auckland, New Zealand (D.L.H.); Amylin Pharmaceuticals LLC, San Diego, California (S.C., D.G.P.); Institute of Veterinary Physiology, Institute of Laboratory Animal Sciences and Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland (T.A.L.); and Intercept Pharmaceuticals, Inc., San Diego, California (J.D.R.)
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30
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Smith PM, Brzezinska P, Hubert F, Mimee A, Maurice DH, Ferguson AV. Leptin influences the excitability of area postrema neurons. Am J Physiol Regul Integr Comp Physiol 2015; 310:R440-8. [PMID: 26719304 DOI: 10.1152/ajpregu.00326.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 12/23/2015] [Indexed: 11/22/2022]
Abstract
The area postrema (AP) is a circumventricular organ with important roles in central autonomic regulation. This medullary structure has been shown to express the leptin receptor and has been suggested to have a role in modulating peripheral signals, indicating energy status. Using RT-PCR, we have confirmed the presence of mRNA for the leptin receptor, ObRb, in AP, and whole cell current-clamp recordings from dissociated AP neurons demonstrated that leptin influenced the excitability of 51% (42/82) of AP neurons. The majority of responsive neurons (62%) exhibited a depolarization (5.3 ± 0.7 mV), while the remaining affected cells (16/42) demonstrated hyperpolarizing effects (-5.96 ± 0.95 mV). Amylin was found to influence the same population of AP neurons. To elucidate the mechanism(s) of leptin and amylin actions in the AP, we used fluorescence resonance energy transfer (FRET) to determine the effect of these peptides on cAMP levels in single AP neurons. Leptin and amylin were found to elevate cAMP levels in the same dissociated AP neurons (leptin: % total FRET response 25.3 ± 4.9, n = 14; amylin: % total FRET response 21.7 ± 3.1, n = 13). When leptin and amylin were coapplied, % total FRET response rose to 53.0 ± 8.3 (n = 6). The demonstration that leptin and amylin influence a subpopulation of AP neurons and that these two signaling molecules have additive effects on single AP neurons to increase cAMP, supports a role for the AP as a central nervous system location at which these circulating signals may act through common intracellular signaling pathways to influence central control of energy balance.
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Affiliation(s)
- Pauline M Smith
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Paulina Brzezinska
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Fabien Hubert
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Andrea Mimee
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Donald H Maurice
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Alastair V Ferguson
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
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31
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Akter R, Cao P, Noor H, Ridgway Z, Tu LH, Wang H, Wong AG, Zhang X, Abedini A, Schmidt AM, Raleigh DP. Islet Amyloid Polypeptide: Structure, Function, and Pathophysiology. J Diabetes Res 2015; 2016:2798269. [PMID: 26649319 PMCID: PMC4662979 DOI: 10.1155/2016/2798269] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/24/2015] [Indexed: 01/29/2023] Open
Abstract
The hormone islet amyloid polypeptide (IAPP, or amylin) plays a role in glucose homeostasis but aggregates to form islet amyloid in type-2 diabetes. Islet amyloid formation contributes to β-cell dysfunction and death in the disease and to the failure of islet transplants. Recent work suggests a role for IAPP aggregation in cardiovascular complications of type-2 diabetes and hints at a possible role in type-1 diabetes. The mechanisms of IAPP amyloid formation in vivo or in vitro are not understood and the mechanisms of IAPP induced β-cell death are not fully defined. Activation of the inflammasome, defects in autophagy, ER stress, generation of reactive oxygen species, membrane disruption, and receptor mediated mechanisms have all been proposed to play a role. Open questions in the field include the relative importance of the various mechanisms of β-cell death, the relevance of reductionist biophysical studies to the situation in vivo, the molecular mechanism of amyloid formation in vitro and in vivo, the factors which trigger amyloid formation in type-2 diabetes, the potential role of IAPP in type-1 diabetes, the development of clinically relevant inhibitors of islet amyloidosis toxicity, and the design of soluble, bioactive variants of IAPP for use as adjuncts to insulin therapy.
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Affiliation(s)
- Rehana Akter
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Ping Cao
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Harris Noor
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Zachary Ridgway
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Ling-Hsien Tu
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Hui Wang
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Amy G. Wong
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Xiaoxue Zhang
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Andisheh Abedini
- Diabetes Research Program, NYU School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Ann Marie Schmidt
- Diabetes Research Program, NYU School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Daniel P. Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
- Research Department of Structural and Molecule Biology, University College London, Gower Street, London WC1E 6BT, UK
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32
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Negative Energy Balance Blocks Neural and Behavioral Responses to Acute Stress by "Silencing" Central Glucagon-Like Peptide 1 Signaling in Rats. J Neurosci 2015. [PMID: 26224855 DOI: 10.1523/jneurosci.3464-14.2015] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
UNLABELLED Previous reports indicate that caloric restriction attenuates anxiety and other behavioral responses to acute stress, and blunts the ability of stress to increase anterior pituitary release of adrenocorticotropic hormone. Since hindbrain glucagon-like peptide-1 (GLP-1) neurons and noradrenergic prolactin-releasing peptide (PrRP) neurons participate in behavioral and endocrine stress responses, and are sensitive to the metabolic state, we examined whether overnight food deprivation blunts stress-induced recruitment of these neurons and their downstream hypothalamic and limbic forebrain targets. A single overnight fast reduced anxiety-like behavior assessed in the elevated-plus maze and acoustic startle test, including marked attenuation of light-enhanced startle. Acute stress [i.e., 30 min restraint (RES) or 5 min elevated platform exposure] robustly activated c-Fos in GLP-1 and PrRP neurons in fed rats, but not in fasted rats. Fasting also significantly blunted the ability of acute stress to activate c-Fos expression within the anterior ventrolateral bed nucleus of the stria terminalis (vlBST). Acute RES stress suppressed dark-onset food intake in rats that were fed ad libitum, whereas central infusion of a GLP-1 receptor antagonist blocked RES-induced hypophagia, and reduced the ability of RES to activate PrRP and anterior vlBST neurons in ad libitum-fed rats. Thus, an overnight fast "silences" GLP-1 and PrRP neurons, and reduces both anxiety-like and hypophagic responses to acute stress. The partial mimicking of these fasting-induced effects in ad libitum-fed rats after GLP-1 receptor antagonism suggests a potential mechanism by which short-term negative energy balance attenuates neuroendocrine and behavioral responses to acute stress. SIGNIFICANCE STATEMENT The results from this study reveal a potential central mechanism for the "metabolic tuning" of stress responsiveness. A single overnight fast, which markedly reduces anxiety-like behavior in rats, reduces or blocks the ability of acute stress to activate hindbrain neurons that are immunoreactive for either prolactin-releasing peptide or glucagon-like peptide 1, and attenuates the activation of their stress-sensitive projection targets in the limbic forebrain. In nonfasted rats, central antagonism of glucagon-like peptide 1 receptors partially mimics the effect of an overnight fast by blocking the ability of acute stress to inhibit food intake, and by attenuating stress-induced activation of hindbrain and limbic forebrain neurons. We propose that caloric restriction attenuates behavioral and physiological responses to acute stress by "silencing" central glucagon-like peptide 1 signaling pathways.
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Louros NN, Tsiolaki PL, Zompra AA, Pappa EV, Magafa V, Pairas G, Cordopatis P, Cheimonidou C, Trougakos IP, Iconomidou VA, Hamodrakas SJ. Structural studies and cytotoxicity assays of “aggregation-prone” IAPP8-16and its non-amyloidogenic variants suggest its important role in fibrillogenesis and cytotoxicity of human amylin. Biopolymers 2015; 104:196-205. [DOI: 10.1002/bip.22650] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 03/10/2015] [Accepted: 03/30/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Nikolaos N. Louros
- Department of Cell Biology and Biophysics; Faculty of Biology, University of Athens; Panepistimiopolis Athens 157 01 Greece
| | - Paraskevi L. Tsiolaki
- Department of Cell Biology and Biophysics; Faculty of Biology, University of Athens; Panepistimiopolis Athens 157 01 Greece
| | | | - Eleni V. Pappa
- Department of Pharmacy; University of Patras; Patras 26504 Greece
| | - Vassiliki Magafa
- Department of Pharmacy; University of Patras; Patras 26504 Greece
| | - George Pairas
- Department of Pharmacy; University of Patras; Patras 26504 Greece
| | - Paul Cordopatis
- Department of Pharmacy; University of Patras; Patras 26504 Greece
| | - Christina Cheimonidou
- Department of Cell Biology and Biophysics; Faculty of Biology, University of Athens; Panepistimiopolis Athens 157 01 Greece
| | - Ioannis P. Trougakos
- Department of Cell Biology and Biophysics; Faculty of Biology, University of Athens; Panepistimiopolis Athens 157 01 Greece
| | - Vassiliki A. Iconomidou
- Department of Cell Biology and Biophysics; Faculty of Biology, University of Athens; Panepistimiopolis Athens 157 01 Greece
| | - Stavros J. Hamodrakas
- Department of Cell Biology and Biophysics; Faculty of Biology, University of Athens; Panepistimiopolis Athens 157 01 Greece
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Babak T, DeVeale B, Tsang EK, Zhou Y, Li X, Smith KS, Kukurba KR, Zhang R, Li JB, van der Kooy D, Montgomery SB, Fraser HB. Genetic conflict reflected in tissue-specific maps of genomic imprinting in human and mouse. Nat Genet 2015; 47:544-9. [PMID: 25848752 PMCID: PMC4414907 DOI: 10.1038/ng.3274] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 03/13/2015] [Indexed: 12/12/2022]
Abstract
Genomic imprinting is an epigenetic process that restricts gene expression to either the maternally or paternally inherited allele. Many theories have been proposed to explain its evolutionary origin, but understanding has been limited by a paucity of data mapping the breadth and dynamics of imprinting within any organism. We generated an atlas of imprinting spanning 33 mouse and 45 human developmental stages and tissues. Nearly all imprinted genes were imprinted in early development and either retained their parent-of-origin expression in adults or lost it completely. Consistent with an evolutionary signature of parental conflict, imprinted genes were enriched for coexpressed pairs of maternally and paternally expressed genes, showed accelerated expression divergence between human and mouse, and were more highly expressed than their non-imprinted orthologs in other species. Our approach demonstrates a general framework for the discovery of imprinting in any species and sheds light on the causes and consequences of genomic imprinting in mammals.
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Affiliation(s)
- Tomas Babak
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Brian DeVeale
- UCSF School of Medicine, UCSF, San Francisco, CA, 94143, USA
| | - Emily K. Tsang
- Department of Pathology, Stanford University, Stanford, CA, 94305, USA
| | - Yiqi Zhou
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Xin Li
- Department of Pathology, Stanford University, Stanford, CA, 94305, USA
| | - Kevin S. Smith
- Department of Pathology, Stanford University, Stanford, CA, 94305, USA
| | - Kim R. Kukurba
- Department of Pathology, Stanford University, Stanford, CA, 94305, USA
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA
| | - Rui Zhang
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA
| | - Jin Billy Li
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA
| | - Derek van der Kooy
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Stephen B. Montgomery
- Department of Pathology, Stanford University, Stanford, CA, 94305, USA
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA
| | - Hunter B. Fraser
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
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Le Foll C, Johnson MD, Dunn-Meynell AA, Boyle CN, Lutz TA, Levin BE. Amylin-induced central IL-6 production enhances ventromedial hypothalamic leptin signaling. Diabetes 2015; 64:1621-31. [PMID: 25409701 PMCID: PMC4407855 DOI: 10.2337/db14-0645] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 11/14/2014] [Indexed: 02/05/2023]
Abstract
Amylin acts acutely via the area postrema to reduce food intake and body weight, but it also interacts with leptin over longer periods of time, possibly via the ventromedial hypothalamus (VMH), to increase leptin signaling and phosphorylation of STAT3. We postulated that amylin enhances VMH leptin signaling by inducing interleukin (IL)-6, which then interacts with its gp130 receptor to activate STAT3 signaling and gene transcription downstream of the leptin receptor. We found that components of the amylin receptor (RAMPs1-3, CTR1a,b) are expressed in cultured VMH astrocytes, neurons, and microglia, as well as in micropunches of arcuate and ventromedial hypothalamic nuclei (VMN). Amylin exposure for 5 days increased IL-6 mRNA expression in VMH explants and microglia by two- to threefold, respectively, as well as protein abundance in culture supernatants by five- and twofold, respectively. Amylin had no similar effects on cultured astrocytes or neurons. In rats, 5 days of amylin treatment decreased body weight gain and/or food intake and increased IL-6 mRNA expression in the VMN. Similar 5-day amylin treatment increased VMN leptin-induced phosphorylation of STAT3 expression in wild-type mice and rats infused with lateral ventricular IgG but not in IL-6 knockout mice or rats infused with ventricular IL-6 antibody. Lateral ventricular infusion of IL-6 antibody also prevented the amylin-induced decrease of body weight gain. These results show that amylin-induced VMH microglial IL-6 production is the likely mechanism by which amylin treatment interacts with VMH leptin signaling to increase its effect on weight loss.
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Affiliation(s)
- Christelle Le Foll
- Department of Neurology and Neurosciences, Rutgers New Jersey Medical School, Newark, NJ
| | - Miranda D Johnson
- Department of Neurology and Neurosciences, Rutgers New Jersey Medical School, Newark, NJ Rutgers Graduate School of Biomedical Sciences at New Jersey Medical School and Rutgers School of Dental Medicine, Newark, NJ
| | | | - Christina N Boyle
- Zurich Center for Integrative Human Physiology, Zurich, Switzerland Institute of Veterinary Physiology, Zurich, Switzerland
| | - Thomas A Lutz
- Zurich Center for Integrative Human Physiology, Zurich, Switzerland Institute of Veterinary Physiology, Zurich, Switzerland Institute of Laboratory Animal Sciences, Zurich, Switzerland
| | - Barry E Levin
- Department of Neurology and Neurosciences, Rutgers New Jersey Medical School, Newark, NJ VA Medical Center, East Orange, NJ
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Tomasello MF, Sinopoli A, Pappalardo G. On the Environmental Factors Affecting the Structural and Cytotoxic Properties of IAPP Peptides. J Diabetes Res 2015; 2015:918573. [PMID: 26582441 PMCID: PMC4637107 DOI: 10.1155/2015/918573] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/05/2015] [Indexed: 12/18/2022] Open
Abstract
Pancreatic islets in type 2 diabetes mellitus (T2DM) patients are characterized by reduced β-cells mass and diffuse extracellular amyloidosis. Amyloid deposition involves the islet amyloid polypeptide (IAPP), a neuropancreatic hormone cosecreted with insulin by β-cells. IAPP is physiologically involved in glucose homeostasis, but it may turn toxic to β-cells owing to its tendency to misfold giving rise to oligomers and fibrils. The process by which the unfolded IAPP starts to self-assemble and the overall factors promoting this conversion are poorly understood. Other open questions are related to the nature of the IAPP toxic species and how exactly β-cells die. Over the last decades, there has been growing consensus about the notion that early molecular assemblies, notably small hIAPP oligomers, are the culprit of β-cells decline. Numerous environmental factors might affect the conformational, aggregation, and cytotoxic properties of IAPP. Herein we review recent progress in the field, focusing on the influences that membranes, pH, and metal ions may have on the conformational conversion and cytotoxicity of full-length IAPP as well as peptide fragments thereof. Current theories proposed for the mechanisms of toxicity will be also summarized together with an outline of the underlying molecular links between IAPP and amyloid beta (Aβ) misfolding.
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Affiliation(s)
| | - Alessandro Sinopoli
- International PhD Program in Translational Biomedicine, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Giuseppe Pappalardo
- CNR Institute of Biostructures and Bioimaging, Via P. Gaifami 18, 95126 Catania, Italy
- *Giuseppe Pappalardo:
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Qiu WQ, Zhu H. Amylin and its analogs: a friend or foe for the treatment of Alzheimer's disease? Front Aging Neurosci 2014; 6:186. [PMID: 25120481 PMCID: PMC4114192 DOI: 10.3389/fnagi.2014.00186] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 07/09/2014] [Indexed: 12/20/2022] Open
Abstract
Amylin, a gut-brain axis hormone, and amyloid-beta peptides (Aβ), a major component of the Alzheimer's disease (AD) brain, share several features, including similar β-sheet secondary structures, binding to the same receptor and being degraded by the same protease, insulin degrading enzyme (IDE). However, while amylin readily crosses the blood brain barrier (BBB) and mediates several activities including improving glucose metabolism, relaxing cerebrovascular structure, modulating inflammatory reaction and perhaps enhancing neural regeneration, Aβ has no known physiological functions. Thus, abundant Aβ in the AD brain could block or interfere with the binding of amylin to its receptor and hinder its functions. Recent studies using animal models for AD demonstrate that amylin and its analog reduce the AD pathology in the brain and improve cognitive impairment in AD. Given that, in addition to amyloid plaques and neurofibrillary tangles, perturbed cerebral glucose metabolism and cerebrovascular damage are the hallmarks of the AD brain, we propose that giving exogenous amylin type peptides have the potential to become a new avenue for the diagnosis and therapeutic of AD. Although amylin's property of self-aggregation may be a limitation to developing it as a therapeutic for AD, its clinical analog, pramlintide containing 3 amino acid differences from amylin, does not aggregate like human amylin, but more potently mediates amylin's activities in the brain. Pramlintide is an effective drug for diabetes with a favorable profile of safety. Thus a randomized, double-blind, placebo-controlled clinical trial should be conducted to examine the efficacy of pramlintide for AD. This review summarizes the knowledge and findings on amylin type peptides and discuss pros and cons for their potential for AD.
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Affiliation(s)
- Wei Qiao Qiu
- Department of Psychiatry, Boston University School of Medicine Boston, MA, USA ; Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine Boston, MA, USA ; Alzheimer's Disease Center, Boston University School of Medicine Boston, MA, USA
| | - Haihao Zhu
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine Boston, MA, USA
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Vasheka IP, Vesel'skyĭ SP, Horenko ZA, Hrinchenko OA, Karbovs'ka LS, Makarchuk MI. The influence of amylin on the bile acid spectrum in rats. ACTA ACUST UNITED AC 2014. [DOI: 10.15407/fz60.03.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Zheng H, Cai L, Rinaman L. Distribution of glucagon-like peptide 1-immunopositive neurons in human caudal medulla. Brain Struct Funct 2014; 220:1213-9. [PMID: 24510283 DOI: 10.1007/s00429-014-0714-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 01/23/2014] [Indexed: 12/25/2022]
Abstract
In rodents, glucagon-like peptide-1 (GLP-1)-positive neurons within the caudal medulla respond to a broad array of interoceptive signals that suppress food intake and drive the hypothalamic-pituitary-adrenal stress axis. The collective results of experiments utilizing cFos to identify activated neurons in rats and mice indicate that GLP-1 neurons are consistently activated by stimuli that present actual or anticipated threats to bodily homeostasis. The distribution of GLP-1-positive neurons in the human brain is unreported. The present study identified GLP-1-positive neurons and mapped their distribution within the caudal medulla in two adult human subjects (one female, one male). The goal of the study was to obtain structural evidence with which to challenge the general hypothesis that functions ascribed to GLP-1 neurons in rodent species may reflect parallel functions that exist in humans. In both human subjects, GLP-1-immunopositive neurons were located within the dorsal medullary region containing the caudal (visceral) nucleus of the solitary tract and in the nearby medullary reticular formation, similar to the distribution of GLP-1 neurons in rats, mice, and Old World monkeys. Quantitative analysis indicates the presence of approximately 6.5-9.3 K GLP-1-positive neurons bilaterally within the human caudal medulla. It will be important in future studies to map the distribution of GLP-1-positive fibers and terminals within higher regions of the human brain, to improve our understanding of how central GLP-1 signaling pathways might influence stress responsiveness, energy balance, and other physiological and behavioral functions.
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Affiliation(s)
- Huiyuan Zheng
- Department of Neuroscience, University of Pittsburgh, A210 Langley Hall, Pittsburgh, PA, 15260, USA
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Mietlicki-Baase EG, Hayes MR. Amylin activates distributed CNS nuclei to control energy balance. Physiol Behav 2014; 136:39-46. [PMID: 24480072 DOI: 10.1016/j.physbeh.2014.01.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 01/13/2014] [Accepted: 01/16/2014] [Indexed: 01/25/2023]
Abstract
Amylin is a pancreas-derived neuropeptide that acts in the central nervous system (CNS) to reduce food intake. Much of the literature describing the anorectic effects of amylin are focused on amylin's actions in the area postrema, a hindbrain circumventricular structure. Although the area postrema is certainly an important site that mediates the intake-suppressive effects of amylin, several pieces of evidence indicate that amylin may also promote negative energy balance through action in additional CNS nuclei, including hypothalamic and mesolimbic structures. Therefore, this review highlights the distributed neural network mediating the feeding effects of amylin signaling with special attention being devoted to the recent discovery that the ventral tegmental area is physiologically relevant for amylin-mediated control of feeding. The production of amylin by alternative, extra-pancreatic sources and its potential relevance to food intake regulation is also considered. Finally, the utility of amylin and amylin-like compounds as a component of combination pharmacotherapies for the treatment of obesity is discussed.
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Affiliation(s)
- Elizabeth G Mietlicki-Baase
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Matthew R Hayes
- Translational Neuroscience Program, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Oral salmon calcitonin protects against impaired fasting glycemia, glucose intolerance, and obesity induced by high-fat diet and ovariectomy in rats. Menopause 2014; 20:785-94. [PMID: 23793169 DOI: 10.1097/gme.0b013e31827c58ab] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Oral salmon calcitonin (sCT) has demonstrated clinical efficacy in treating osteoporosis in postmenopausal women. The postmenopausal state is also associated with obesity-related insulin resistance (IR) and type 2 diabetes. The aim of this study was to investigate the preventive effects of oral sCT on energy and glucose homeostasis in high-fat diet (HFD)- and ovariectomy (OVX)-induced obese rats. Furthermore, the weight-regulatory and gluco-regulatory effects of short-term oral sCT intervention on HFD-induced obese rats were explored. METHODS For prevention, female rats exposed to HFD with or without OVX were treated with oral sCT for 5 weeks. As intervention, HFD-induced obese male rats were treated with oral sCT for 4 days. Body weight, food intake, and plasma glucose, insulin, and leptin levels were measured, and the clinical homeostasis model assessment for insulin resistance (HOMA-IR) index was calculated. In addition, oral glucose tolerance was evaluated in the systemic and portal circulations. RESULTS For prevention, oral sCT reduced body weight by ∼16% to 19% (P < 0.001), reduced plasma insulin and leptin by ∼50%, and improved impaired fasting glycemia (P < 0.05) concomitantly with amelioration of IR (HOMA-IR; P < 0.01) in HFD- and OVX-induced obesity. Furthermore, oral sCT significantly reduced the incremental area under the curve for plasma glucose and insulin by ∼40% and ∼70%, respectively, during glucose tolerance testing. As intervention in HFD-induced obese rats, oral sCT reduced body weight, fasting glycemia, and insulinemia in conjunction with HOMA-IR (P < 0.001). Finally, oral sCT alleviated glucose intolerance predominantly in the portal circulation. CONCLUSIONS Oral sCT treatment displays weight-regulatory and glucoregulatory efficacy in HFD- and OVX-induced obese rats, indicating the clinical usefulness of oral sCT in postmenopausal obesity-related IR and type 2 diabetes.
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Abstract
Individual meals are products of a complex interaction of signals related to both short-term and long-term availability of energy stores. In addition to maintaining the metabolic demands of the individual in the short term, levels of energy intake must also maintain and defend body weight over longer periods. To accomplish this, satiety pathways are regulated by a sophisticated network of endocrine and neuroendocrine pathways. Higher brain centers modulate meal size through descending inputs to caudal brainstem regions responsible for the motor pattern generators associated with ingestion. Gastric and intestinal signals interact with central nervous system pathways to terminate food intake. These inputs can be modified as a function of internal metabolic signals, external environmental influences, and learning to regulate meal size.
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Lutz TA. The interaction of amylin with other hormones in the control of eating. Diabetes Obes Metab 2013; 15:99-111. [PMID: 22862822 DOI: 10.1111/j.1463-1326.2012.01670.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2012] [Revised: 07/20/2012] [Accepted: 07/28/2012] [Indexed: 11/30/2022]
Abstract
Twenty years of research established amylin as an important control of energy homeostasis. Amylin controls nutrient and energy fluxes by reducing energy intake, by modulating nutrient utilization via an inhibition of postprandial glucagon secretion and by increasing energy disposal via a prevention of compensatory decreases of energy expenditure in weight reduced individuals. Like many other gastrointestinal hormones, amylin is secreted in response to meals and it reduces eating by promoting meal-ending satiation. Not surprisingly, amylin interacts with many of these hormones to control eating. These interactions seem to occur at different levels because amylin seems to mediate the eating inhibitory effect of some of these gastrointestinal hormones, and the combination of some of these hormones seems to lead to a stronger reduction in eating than single hormones alone. Amylin's effect on eating is thought to be mediated by a stimulation of specific amylin receptors in the area postrema. Secondary brain sites that were defined to mediate amylin action - and hence potential additional sites of interaction with other hormones - include the nucleus of the solitary tract, the lateral parabrachial nucleus, the lateral hypothalamic area and other hypothalamic nuclei. The focus of this review is to summarize the current knowledge of amylin interactions in the control of eating. In most cases, these interactions have only been studied at a descriptive rather than a mechanistic level and despite the clear knowledge on primary sites of amylin action, the interaction sites between amylin and other hormones are often unknown.
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Affiliation(s)
- T A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland.
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Cao P, Marek P, Noor H, Patsalo V, Tu LH, Wang H, Abedini A, Raleigh DP. Islet amyloid: from fundamental biophysics to mechanisms of cytotoxicity. FEBS Lett 2013; 587:1106-18. [PMID: 23380070 DOI: 10.1016/j.febslet.2013.01.046] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/22/2013] [Accepted: 01/23/2013] [Indexed: 12/21/2022]
Abstract
Pancreatic islet amyloid is a characteristic feature of type 2 diabetes. The major protein component of islet amyloid is the polypeptide hormone known as islet amyloid polypeptide (IAPP, or amylin). IAPP is stored with insulin in the β-cell secretory granules and is released in response to the stimuli that lead to insulin secretion. IAPP is normally soluble and is natively unfolded in its monomeric state, but forms islet amyloid in type 2 diabetes. Islet amyloid is not the cause of type 2 diabetes, but it leads to β-cell dysfunction and cell death, and contributes to the failure of islet cell transplantation. The mechanism of IAPP amyloid formation is not understood and the mechanisms of cytotoxicity are not fully defined.
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Affiliation(s)
- Ping Cao
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
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Fukuda T, Hirai Y, Maezawa H, Kitagawa Y, Funahashi M. Electrophysiologically identified presynaptic mechanisms underlying amylinergic modulation of area postrema neuronal excitability in rat brain slices. Brain Res 2013; 1494:9-16. [DOI: 10.1016/j.brainres.2012.11.051] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 11/28/2012] [Accepted: 11/29/2012] [Indexed: 11/30/2022]
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Roth JD. Amylin and the regulation of appetite and adiposity: recent advances in receptor signaling, neurobiology and pharmacology. Curr Opin Endocrinol Diabetes Obes 2013. [PMID: 23183359 DOI: 10.1097/med.0b013e32835b896f] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
PURPOSE OF REVIEW This review focuses on recent advances in receptor signaling, neurobiology, and pharmacological interactions of amylin with nutritive status, as well as other metabolism-related regulatory signals. RECENT FINDINGS Manipulation of components of the amylin receptor complex revealed important roles for the accessory proteins of amylin receptors in energy balance. In-vitro findings point to potential novel sites of action and postreceptor signaling pathways activated by amylin. Neurobiological studies elucidated how amylin activation of hindbrain neural circuitry modulates hypothalamic signaling and responsiveness to leptin. The notion of 'amylin resistance' was addressed in several models (drug or diet-induced hyper-amylinemia). Finally, progress in the design and delivery of amylinomimetics is briefly discussed. SUMMARY Collectively, these mechanistic studies deepen our understanding of the role of endogenous amylin in the regulation of appetite and adiposity, and hopefully will help guide research efforts towards the development of more effective amylin-based therapies for metabolic diseases.
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Maniscalco JW, Kreisler AD, Rinaman L. Satiation and stress-induced hypophagia: examining the role of hindbrain neurons expressing prolactin-releasing Peptide or glucagon-like Peptide 1. Front Neurosci 2013; 6:199. [PMID: 23346044 PMCID: PMC3549516 DOI: 10.3389/fnins.2012.00199] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 12/31/2012] [Indexed: 12/20/2022] Open
Abstract
Neural circuits distributed within the brainstem, hypothalamus, and limbic forebrain interact to control food intake and energy balance under normal day-to-day conditions, and in response to stressful conditions under which homeostasis is threatened. Experimental studies using rats and mice have generated a voluminous literature regarding the functional organization of circuits that inhibit food intake in response to satiety signals, and in response to stress. Although the central neural bases of satiation and stress-induced hypophagia often are studied and discussed as if they were distinct, we propose that both behavioral states are generated, at least in part, by recruitment of two separate but intermingled groups of caudal hindbrain neurons. One group comprises a subpopulation of noradrenergic (NA) neurons within the caudal nucleus of the solitary tract (cNST; A2 cell group) that is immunopositive for prolactin-releasing peptide (PrRP). The second group comprises non-adrenergic neurons within the cNST and nearby reticular formation that synthesize glucagon-like peptide 1 (GLP-1). Axonal projections from PrRP and GLP-1 neurons target distributed brainstem and forebrain regions that shape behavioral, autonomic, and endocrine responses to actual or anticipated homeostatic challenge, including the challenge of food intake. Evidence reviewed in this article supports the view that hindbrain PrRP and GLP-1 neurons contribute importantly to satiation and stress-induced hypophagia by modulating the activity of caudal brainstem circuits that control food intake. Hindbrain PrRP and GLP-1 neurons also engage hypothalamic and limbic forebrain networks that drive parallel behavioral and endocrine functions related to food intake and homeostatic challenge, and modulate conditioned and motivational aspects of food intake.
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Affiliation(s)
- James W Maniscalco
- Department of Neuroscience, University of Pittsburgh Pittsburgh, PA, USA
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Abedini A, Schmidt AM. Mechanisms of islet amyloidosis toxicity in type 2 diabetes. FEBS Lett 2013; 587:1119-27. [PMID: 23337872 DOI: 10.1016/j.febslet.2013.01.017] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 01/10/2013] [Accepted: 01/10/2013] [Indexed: 12/19/2022]
Abstract
Amyloid formation by the neuropancreatic hormone, islet amyloid polypeptide (IAPP or amylin), one of the most amyloidogenic sequences known, leads to islet amyloidosis in type 2 diabetes and to islet transplant failure. Under normal conditions, IAPP plays a role in the maintenance of energy homeostasis by regulating several metabolic parameters, such as satiety, blood glucose levels, adiposity and body weight. The mechanisms of IAPP amyloid formation, the nature of IAPP toxic species and the cellular pathways that lead to pancreatic β-cell toxicity are not well characterized. Several mechanisms of toxicity, including receptor and non-receptor-mediated events, have been proposed. Analogs of IAPP have been approved for the treatment of diabetes and are under investigation for the treatment of obesity.
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Affiliation(s)
- Andisheh Abedini
- Diabetes Research Program, Division of Endocrinology, Department of Medicine, New York University Medical Center, 550 First Avenue, Smilow 906, New York, NY 10016, USA.
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Sherafat-Kazemzadeh R, Yanovski SZ, Yanovski JA. Pharmacotherapy for childhood obesity: present and future prospects. Int J Obes (Lond) 2013; 37:1-15. [PMID: 22929210 PMCID: PMC3522799 DOI: 10.1038/ijo.2012.144] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Pediatric obesity is a serious medical condition associated with significant comorbidities during childhood and adulthood. Lifestyle modifications are essential for treating children with obesity, yet many have insufficient response to improve health with behavioral approaches alone. This review summarizes the relatively sparse data on pharmacotherapy for pediatric obesity and presents information on obesity medications in development. Most previously studied medications demonstrated, at best, modest effects on body weight and obesity-related conditions. It is to be hoped that the future will bring new drugs targeting specific obesity phenotypes that will allow clinicians to use etiology-specific, and therefore more effective, anti-obesity therapies.
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Affiliation(s)
- Roya Sherafat-Kazemzadeh
- Section on Growth and Obesity, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development
| | - Susan Z. Yanovski
- Section on Growth and Obesity, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development
- Division of Digestive Diseases and Nutrition, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health
| | - Jack A. Yanovski
- Section on Growth and Obesity, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development
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Panickar KS. Effects of dietary polyphenols on neuroregulatory factors and pathways that mediate food intake and energy regulation in obesity. Mol Nutr Food Res 2012; 57:34-47. [DOI: 10.1002/mnfr.201200431] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 08/08/2012] [Accepted: 08/22/2012] [Indexed: 12/20/2022]
Affiliation(s)
- Kiran S. Panickar
- Department of Pediatrics; University of Maryland School of Medicine; Baltimore MD USA
- Diet, Genomics, & Immunology Laboratory; Beltsville Human Nutrition Research Center; Agricultural Research Service; United States Department of Agriculture; Beltsville MD USA
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