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Bennici G, Almahasheer H, Alghrably M, Valensin D, Kola A, Kokotidou C, Lachowicz J, Jaremko M. Mitigating diabetes associated with reactive oxygen species (ROS) and protein aggregation through pharmacological interventions. RSC Adv 2024; 14:17448-17460. [PMID: 38813124 PMCID: PMC11135279 DOI: 10.1039/d4ra02349h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 05/22/2024] [Indexed: 05/31/2024] Open
Abstract
Diabetes mellitus, a complex metabolic disorder, presents a growing global health challenge. In 2021, there were 529 million diabetics worldwide. At the super-regional level, Oceania, the Middle East, and North Africa had the highest age-standardized rates. The majority of cases of diabetes in 2021 (>90.0%) were type 2 diabetes, which is largely indicative of the prevalence of diabetes in general, particularly in older adults (K. L. Ong, et al., Global, regional, and national burden of diabetes from 1990 to 2021, with projections of prevalence to 2050: a systematic analysis for the Global Burden of Disease Study 2021, Lancet, 2023, 402(10397), 203-234). Nowadays, slowing the progression of diabetic complications is the only effective way to manage diabetes with the available therapeutic options. However, novel biomarkers and treatments are urgently needed to control cytokine secretion, advanced glycation end products (AGEs) production, vascular inflammatory effects, and cellular death. Emerging research has highlighted the intricate interplay between reactive oxygen species (ROS) and protein aggregation in the pathogenesis of diabetes. In this scenario, the main aim of this paper is to provide a comprehensive review of the current understanding of the molecular mechanisms underlying ROS-induced cellular damage and protein aggregation, specifically focusing on their contribution to diabetes development. The role of ROS as key mediators of oxidative stress in diabetes is discussed, emphasizing their impact on cellular components and signaling. Additionally, the involvement of protein aggregation in impairing cellular function and insulin signaling is explored. The synergistic effects of ROS and protein aggregation in promoting β-cell dysfunction and insulin resistance are examined, shedding light on potential targets for therapeutic intervention.
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Affiliation(s)
- Giulia Bennici
- Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia
| | - Hanan Almahasheer
- Department of Biology, College of Science, Imam Abdulrahman Bin Faisal University (IAU) Dammam 31441-1982 Saudi Arabia
| | - Mawadda Alghrably
- Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia
| | - Daniela Valensin
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena Via Aldo Moro 2 53100 Siena Italy
| | - Arian Kola
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena Via Aldo Moro 2 53100 Siena Italy
| | - Chrysoula Kokotidou
- Department of Materials Science and Technology, University of Crete 70013 Heraklion Crete Greece
- Institute of Electronic Structure and Laser (IESL) FORTH 70013 Heraklion Crete Greece
| | - Joanna Lachowicz
- Department of Population Health, Division of Environmental Health and Occupational Medicine, Wroclaw Medical University Mikulicza-Radeckiego 7 Wroclaw PL 50-368 Poland
| | - Mariusz Jaremko
- Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia
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Guillemain G, Lacapere JJ, Khemtemourian L. Targeting hIAPP fibrillation: A new paradigm to prevent β-cell death? BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:184002. [PMID: 35868406 DOI: 10.1016/j.bbamem.2022.184002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/20/2022] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
Loss of pancreatic β-cell mass is deleterious for type 2 diabetes patients since it reduces insulin production, critical for glucose homeostasis. The main research axis developed over the last few years was to generate new pancreatic β-cells or to transplant pancreatic islets as occurring for some specific type 1 diabetes patients. We evaluate here a new paradigm consisting in preservation of β-cells by prevention of human islet amyloid polypeptide (hIAPP) oligomers and fibrils formation leading to pancreatic β-cell death. We review the hIAPP physiology and the pathology that contributes to β-cell destruction, deciphering the various cellular steps that could be involved. Recent progress in understanding other amyloidosis such as Aβ, Tau, α-synuclein or prion, involved in neurodegenerative processes linked with inflammation, has opened new research lines of investigations to preserve neuronal cells. We evaluate and estimate their transposition to the pancreatic β-cells preservation. Among them is the control of reactive oxygen species (ROS) production occurring with inflammation and the possible implication of the mitochondrial translocator protein as a diagnostic and therapeutic target. The present review also focuses on other amyloid forming proteins from molecular to physiological and physiopathological points of view that could help to better decipher hIAPP-induced β-cell death mechanisms and to prevent hIAPP fibril formation.
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Affiliation(s)
- Ghislaine Guillemain
- Sorbonne Université, Institut Hospitalo-Universitaire, Inserm UMR_S938, Institute of Cardio metabolism and Nutrition (ICAN), Centre de recherche de St-Antoine (CRSA), 27 rue de Chaligny, F-75012 Paris, France.
| | - Jean-Jacques Lacapere
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS UMR 7203, Laboratoire des BioMolécules (LBM), 4 place Jussieu, F-75005 Paris, France.
| | - Lucie Khemtemourian
- CBMN, CNRS UMR 5248, IPB, Univ. Bordeaux, Allée Geoffroy Saint-Hilaire, F-33600 Pessac, France.
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Verberne AJM, Mussa BM. Neural control of pancreatic peptide hormone secretion. Peptides 2022; 152:170768. [PMID: 35189258 DOI: 10.1016/j.peptides.2022.170768] [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: 01/24/2022] [Revised: 02/10/2022] [Accepted: 02/12/2022] [Indexed: 11/20/2022]
Abstract
Pancreatic peptide hormone secretion is inextricably linked to maintenance of normal levels of blood glucose. In animals and man, pancreatic peptide hormone secretion is controlled, at least in part, by input from parasympathetic (vagal) premotor neurons that are found principally in the dorsal motor nucleus of the vagus (DMV). Iatrogenic (insulin-induced) hypoglycaemia evokes a homeostatic response commonly referred to as the glucose counter-regulatory response. This homeostatic response is of particular importance in Type 1 diabetes in which episodes of hypoglycaemia are common, debilitating and lead to suboptimal control of blood glucose. Glucagon is the principal counterregulatory hormone but for reasons unknown, its secretion during insulin-induced hypoglycaemia is impaired. Pancreatic parasympathetic neurons are distinguishable electrophysiologically from those that control other (e.g. gastric) functions and are controlled by supramedullary inputs from hypothalamic structures such as the perifornical region. During hypoglycaemia, glucose-sensitive, GABAergic neurons in the ventromedial hypothalamus are inhibited leading to disinhibition of perifornical orexin neurons with projections to the DMV which, in turn, leads to increased secretion of glucagon.
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Affiliation(s)
- Anthony J M Verberne
- Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria 3084, Australia.
| | - Bashair M Mussa
- Basic Medical Science Department, College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates
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Mediators of Amylin Action in Metabolic Control. J Clin Med 2022; 11:jcm11082207. [PMID: 35456307 PMCID: PMC9025724 DOI: 10.3390/jcm11082207] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/08/2022] [Accepted: 04/13/2022] [Indexed: 02/06/2023] Open
Abstract
Amylin (also called islet amyloid polypeptide (IAPP)) is a pancreatic beta-cell hormone that is co-secreted with insulin in response to nutrient stimuli. The last 35 years of intensive research have shown that amylin exerts important physiological effects on metabolic control. Most importantly, amylin is a physiological control of meal-ending satiation, and it limits the rate of gastric emptying and reduces the secretion of pancreatic glucagon, in particular in postprandial states. The physiological effects of amylin and its analogs are mediated by direct brain activation, with the caudal hindbrain playing the most prominent role. The clarification of the structure of amylin receptors, consisting of the calcitonin core receptor plus receptor-activity modifying proteins, aided in the development of amylin analogs with a broad pharmacological profile. The general interest in amylin physiology and pharmacology was boosted by the finding that amylin is a sensitizer to the catabolic actions of leptin. Today, amylin derived analogs are considered to be among the most promising approaches for the pharmacotherapy against obesity. At least in conjunction with insulin, amylin analogs are also considered important treatment options in diabetic patients, so that new drugs may soon be added to the only currently approved compound pramlintide (Symlin®). This review provides a brief summary of the physiology of amylin’s mode of actions and its role in the control of the metabolism, in particular energy intake and glucose metabolism.
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Honegger M, Lutz TA, Boyle CN. Hypoglycemia attenuates acute amylin-induced reduction of food intake in male rats. Physiol Behav 2021; 237:113435. [PMID: 33933418 DOI: 10.1016/j.physbeh.2021.113435] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/09/2021] [Accepted: 04/23/2021] [Indexed: 12/17/2022]
Abstract
The ability of amylin to inhibit gastric emptying and glucagon secretion in rats is reduced under hypoglycemic conditions. These effects are considered part of a fail-safe mechanism that prevents amylin from further decreasing nutrient supply when blood glucose levels are low. Because these actions and amylin-induced satiation are mediated by the area postrema (AP), it is plausible that these phenomena are based on the co-sensitivity of AP neurons to amylin and glucose. Using hyperinsulinemic glucose clamps in unrestrained and freely-feeding rats, we investigated whether amylin's ability to inhibit food intake is also reduced by hypoglycemia (HYPO). Following an 18 h fast, rats were infused with insulin and glucose for 45 min to clamp blood glucose at baseline levels (between 90 and 100 mg/dL). HYPO (approximately 55 mg/dL) was induced between 45 and 60 min and then maintained for the remainder of the clamp. Rats were injected with amylin (20 µg/kg) or saline and offered normal chow at 85 min. Food intake was measured at 30 and 60 min after amylin. Control hyperinsulinemic/euglycemic (EU) rats were maintained at approximately 150 mg/dL (which is a physiological periprandial glucose level) before and after amylin injection. Terminal experiments tested the effect of amylin to induce the phosphorylation of ERK, a marker of amylin action in the AP, in EU and HYPO conditions. Amylin significantly reduced 30- and 60-min food intake in EU rats, but the effect at 60-min was attenuated in HYPO rats. Interestingly, glucose infusion rate had to be dramatically reduced at meal onset in saline-treated, but not in amylin-treated, EU or HYPO rats; this suggests that meal-related glucose appearance in the blood was inhibited by amylin under both EU and HYPO. Finally, amylin induced a similar pERK response in the AP in EU and HYPO rats. We conclude that amylin's action to decrease eating is blunted in hypoglycemia, and this effect seems to be downstream from amylin-induced pERK in AP neurons. These data allow us to extend the idea of a hypoglycemic brake on amylin's actions to its food intake-reducing effect, but also demonstrate that amylin can buffer meal-induced glucose appearance at EU and HYPO levels.
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Affiliation(s)
- Miriam Honegger
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich (UZH), 8057 Zurich, Switzerland
| | - Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich (UZH), 8057 Zurich, Switzerland; Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Christina N Boyle
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich (UZH), 8057 Zurich, Switzerland.
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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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Ling W, Huang YM, Qiao YC, Zhang XX, Zhao HL. Human Amylin: From Pathology to Physiology and Pharmacology. Curr Protein Pept Sci 2019; 20:944-957. [DOI: 10.2174/1389203720666190328111833] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 03/12/2019] [Accepted: 03/15/2019] [Indexed: 12/18/2022]
Abstract
The histopathological hallmark of type 2 diabetes is islet amyloid implicated in the developing treatment options. The major component of human islet amyloid is 37 amino acid peptide known as amylin or islet amyloid polypeptide (IAPP). Amylin is an important hormone that is co-localized, copackaged, and co-secreted with insulin from islet β cells. Physiologically, amylin regulates glucose homeostasis by inhibiting insulin and glucagon secretion. Furthermore, amylin modulates satiety and inhibits gastric emptying via the central nervous system. Normally, human IAPP is soluble and natively unfolded in its monomeric state. Pathologically, human IAPP has a propensity to form oligomers and aggregate. The oligomers show misfolded α-helix conformation and can further convert themselves to β-sheet-rich fibrils as amyloid deposits. The pathological findings and physiological functions of amylin have led to the introduction of pramlintide, an amylin analog, for the treatment of diabetes. The history of amylin’s discovery is a representative example of how a pathological finding can translate into physiological exploration and lead to pharmacological intervention. Understanding the importance of transitioning from pathology to physiology and pharmacology can provide novel insight into diabetes mellitus and Alzheimer's disease.
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Affiliation(s)
- Wei Ling
- Center for Diabetic Systems Medicine, Guangxi Key Laboratory of Excellence, Guilin Medical University, Guilin 541004, China
| | - Yan-Mei Huang
- Center for Diabetic Systems Medicine, Guangxi Key Laboratory of Excellence, Guilin Medical University, Guilin 541004, China
| | - Yong-Chao Qiao
- Department of Laboratory, the Affiliated Hospital of Guilin Medical University, Guilin 541004, China
| | - Xiao-Xi Zhang
- Center for Diabetic Systems Medicine, Guangxi Key Laboratory of Excellence, Guilin Medical University, Guilin 541004, China
| | - Hai-Lu Zhao
- Center for Diabetic Systems Medicine, Guangxi Key Laboratory of Excellence, Guilin Medical University, Guilin 541004, China
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Lu L, Deng Y, Li X, Li H, Karniadakis GE. Understanding the Twisted Structure of Amyloid Fibrils via Molecular Simulations. J Phys Chem B 2018; 122:11302-11310. [PMID: 30106299 DOI: 10.1021/acs.jpcb.8b07255] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Accumulation and aggregation of amyloid are associated with the pathogenesis of many human diseases, such as Alzheimer's disease and Type 2 diabetes mellitus. Therefore, a quantitative understanding of the molecular mechanisms causing different aggregated structures and biomechanical properties of amyloid fibrils could shed some light into the progression of these diseases. In this work, we develop coarse-grained molecular dynamics (CGMD) models to simulate the dynamic self-assembly of two types of amyloids (amylin and amyloid β (Aβ)). We investigate the structural and mechanical properties of different types of aggregated amyloid fibrils. Our simulations demonstrate that amyloid fibrils could result from longitudinal growth of protofilament bundles, confirming one of the hypotheses on the fibril formation. In addition, we find that the persistence length of amylin fibrils increases concurrently with their pitch length, suggesting that the bending stiffness of amylin fibrils becomes larger when the amylin fibrils are less twisted. Similar results are observed for Aβ fibrils. These findings quantify the connection between the structural and the biomechanical properties of the fibrils. The CGMD models developed in this work can be potentially used to examine efficacy of anti-aggregation drugs, which could help in developing new treatments.
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Affiliation(s)
- Lu Lu
- Division of Applied Mathematics , Brown University , Providence , Rhode Island 02912 , United States
| | - Yixiang Deng
- School of Engineering , Brown University , Providence , Rhode Island 02912 , United States
| | - Xuejin Li
- Division of Applied Mathematics , Brown University , Providence , Rhode Island 02912 , United States
| | - He Li
- Division of Applied Mathematics , Brown University , Providence , Rhode Island 02912 , United States
| | - George Em Karniadakis
- Division of Applied Mathematics , Brown University , Providence , Rhode Island 02912 , United States
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Abstract
Obesity-related co-morbidities decrease life quality, reduce working ability and lead to early death. The total amount of dietary fat consumption may be the most potent food-related risk factor for weight gain. In this respect, dietary intake of high-caloric, high-fat diets due to chronic over-eating and sedentary lifestyle lead to increased storage of triglycerides not only in adipose tissue but also ectopically in other tissues . Increased plasma concentrations of non-esterified free fatty acids and lipid-overloaded hypertrophic adipocytes may cause insulin resistance in an inflammation-independent manner. Even in the absence of metabolic disorders, mismatch between fatty acid uptake and utilization leads to the accumulation of toxic lipid species resulting in organ dysfunction. Lipid-induced apoptosis, ceramide accumulation, reactive oxygen species overproduction, endoplasmic reticulum stress, and mitochondrial dysfunction may play role in the pathogenesis of lipotoxicity. The hypothalamus senses availability of circulating levels of glucose, lipids and amino acids, thereby modifies feeding according to the levels of those molecules. However, the hypothalamus is also similarly vulnerable to lipotoxicity as the other ectopic lipid accumulated tissues. Chronic overnutrition most likely provides repetitive and persistent signals that up-regulate inhibitor of nuclear factor kappa B kinase beta subunit/nuclear factor kappa B (IKKβ/NF-κB) in the hypothalamus before the onset of obesity. However, the mechanisms by which high-fat diet induced peripheral signals affect the hypothalamic arcuate nucleus remain largely unknown. In this chapter, besides lipids and leptin, the role of glucose and insulin on specialized fuel-sensing neurons of hypothalamic neuronal circuits has been debated.
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Amylin-mediated control of glycemia, energy balance, and cognition. Physiol Behav 2016; 162:130-40. [PMID: 26922873 DOI: 10.1016/j.physbeh.2016.02.034] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/20/2016] [Accepted: 02/22/2016] [Indexed: 12/26/2022]
Abstract
Amylin, a peptide hormone produced in the pancreas and in the brain, has well-established physiological roles in glycemic regulation and energy balance control. It improves postprandial blood glucose levels by suppressing gastric emptying and glucagon secretion; these beneficial effects have led to the FDA-approved use of the amylin analog pramlintide in the treatment of diabetes mellitus. Amylin also acts centrally as a satiation signal, reducing food intake and body weight. The ability of amylin to promote negative energy balance, along with its unique capacity to cooperatively facilitate or enhance the intake- and body weight-suppressive effects of other neuroendocrine signals like leptin, have made amylin a leading target for the development of novel pharmacotherapies for the treatment of obesity. In addition to these more widely studied effects, a growing body of literature suggests that amylin may play a role in processes related to cognition, including the neurodegeneration and cognitive deficits associated with Alzheimer's disease (AD). Although the function of amylin in AD is still unclear, intriguing recent reports indicate that amylin may improve cognitive ability and reduce hallmarks of neurodegeneration in the brain. The frequent comorbidity of diabetes mellitus and obesity, as well as the increased risk for and occurrence of AD associated with these metabolic diseases, suggests that amylin-based pharmaceutical strategies may provide multiple therapeutic benefits. This review will discuss the known effects of amylin on glycemic regulation, energy balance control, and cognitive/motivational processes. Particular focus will be devoted to the current and/or potential future clinical use of amylin pharmacotherapies for the treatment of diseases in each of these realms.
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Abstract
Despite improvements in the pharmacodynamics of injectable insulin and better insulin delivery systems, glucose control remains suboptimal in the majority of individuals with Type 1 diabetes. Profound defects in the physiological processes that normally maintain glucose homeostasis contribute to the difficulty in achieving glycaemic targets. Non-insulin-based adjunct treatments offer a potential means of complementing intensive insulin therapy in Type 1 diabetes through addressing some of the physiological disturbances that result from endogenous β-cell destruction, particularly through preservation of β-cell mass and prevention of apoptosis, and suppression of α-cell glucagon release in the postprandial state. The former approach applies most readily to newly diagnosed C-peptide-positive Type 1 diabetes, while the latter to established C-peptide-negative Type 1 diabetes. This review focuses primarily on the clinical trial data available on the use of non-insulin-based therapies in longer-duration Type 1 diabetes. We conclude that metformin may prove useful in macrovascular disease reduction, while pramlintide, glucagon-like peptide-1 agonists, dipeptidyl peptidase-4 inhibitors and leptin co-therapies may reduce HbA(1c) , glucose variability, postprandial glucose excursions and body weight. These early studies are encouraging and offer novel and potentially very effective approaches to the treatment of Type 1 diabetes, but the evidence is largely restricted to small, often uncontrolled trials. As such, these therapies cannot be currently recommended for routine clinical practice. There is a clear need to support large, multi-centre randomized controlled trials designed to establish whether adjunct insulin therapy has a place in the modern management of Type 1 diabetes.
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Affiliation(s)
- P George
- Medical Research Institute, University of Dundee, Ninewells Hospital and Medical School
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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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A Single Pseudoproline and Microwave Solid Phase Peptide Synthesis Facilitates an Efficient Synthesis of Human Amylin 1–37. Int J Pept Res Ther 2012. [DOI: 10.1007/s10989-012-9325-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Bailey RJ, Walker CS, Ferner AH, Loomes KM, Prijic G, Halim A, Whiting L, Phillips ARJ, Hay DL. Pharmacological characterization of rat amylin receptors: implications for the identification of amylin receptor subtypes. Br J Pharmacol 2012; 166:151-67. [PMID: 22014233 DOI: 10.1111/j.1476-5381.2011.01717.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
Abstract
BACKGROUND AND PURPOSE Amylin (Amy) is an important glucoregulatory peptide and AMY receptors are clinical targets for diabetes and obesity. Human (h) AMY receptor subtypes are complexes of the calcitonin (CT) receptor with receptor activity-modifying proteins (RAMPs); their rodent counterparts have not been characterized. To allow identification of the most clinically relevant receptor subtype, the elucidation of rat (r) AMY receptor pharmacology is necessary. EXPERIMENTAL APPROACH Receptors were transiently transfected into COS-7 cells and cAMP responses measured in response to different agonists, with or without antagonists. Competition binding experiments were performed to determine rAmy affinity. KEY RESULTS rCT was the most potent agonist of rCT((a)) receptors, whereas rAmy was most potent at rAMY(1(a)) and rAMY(3(a)) receptors. rAmy bound to these receptors with high affinity. Rat α-calcitonin gene-related peptide (CGRP) was equipotent to rAmy at both AMY receptors. Rat adrenomedullin (AM) and rAM2/intermedin activated all three receptors but were most effective at rAMY(3(a)) . AC187, AC413 and sCT(8-32) were potent antagonists at all three receptors. rαCGRP(8-37) displayed selectivity for rAMY receptors over rCT((a)) receptors. rAMY(8-37) was a weak antagonist but was more effective at rAMY(1(a)) than rAMY(3(a)) . CONCLUSIONS AND IMPLICATIONS AMY receptors were generated by co-expression of rCT((a)) with rRAMP1 or 3, forming rAMY(1(a)) and rAMY(3(a)) receptors, respectively. CGRP was more potent at rAMY than at hAMY receptors. No antagonist tested was able to differentiate the rAMY receptor subtypes. The data emphasize the need for and provide a useful resource for developing new CT or AMY receptor ligands as pharmacological tools or potential clinical candidates.
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Affiliation(s)
- R J Bailey
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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Brainstem sensing of meal-related signals in energy homeostasis. Neuropharmacology 2012; 63:31-45. [DOI: 10.1016/j.neuropharm.2012.03.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 03/12/2012] [Accepted: 03/23/2012] [Indexed: 11/15/2022]
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Abstract
Amylin's best investigated function is to reduce eating via a meal size effect by promoting meal-ending satiation. This effect seems to depend on an activation of specific area postrema neurons. Brain areas that convey the neural signal to the forebrain include the nucleus of the solitary tract and the lateral parabrachial nucleus. Acute application of amylin modulates the activity of hypothalamic areas involved in the control of eating, namely, the lateral hypothalamic area and possibly the ventromedial hypothalamic nucleus. Amylin also interacts with other satiating signals, such as cholecystokinin, presumably in the brainstem. Interestingly, amylin also exhibits characteristics of adiposity signals; plasma levels of amylin are higher in obese individuals, chronic infusion of amylin into the brain reduces body weight gain and adiposity, and infusion of amylin antagonists increases adiposity. Furthermore, amylin maintains energy expenditure at higher levels than would be expected considering its body weight-lowering effect. However, much less is known (e.g., site of action, signaling pathways, differential activation of brain sites, and, most importantly, physiological relevance) with respect to its role as adiposity signal and regulator of energy expenditure than about its satiating action. Notwithstanding, and perhaps because amylin resistance does not seem to be a general and prohibitive concomitant of obesity, animal data and recent clinical data in humans indicate that amylin is a very promising candidate for the treatment of obesity. Amylin seems to be particularly effective when combined with other hormones such as leptin.
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Affiliation(s)
- Thomas Alexander Lutz
- Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology, University of Zurich, Switzerland.
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Lutz TA. Steve Woods's contribution to research on amylin's eating inhibitory effect. Physiol Behav 2011; 103:25-30. [DOI: 10.1016/j.physbeh.2010.10.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 10/15/2010] [Accepted: 10/20/2010] [Indexed: 10/18/2022]
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Lutz TA. The role of amylin in the control of energy homeostasis. Am J Physiol Regul Integr Comp Physiol 2010; 298:R1475-84. [PMID: 20357016 DOI: 10.1152/ajpregu.00703.2009] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amylin is an important player in the control of nutrient fluxes. Amylin reduces eating via a meal size effect by promoting meal-ending satiation. This effect seems to depend on a direct action in the area postrema (AP), which is an area rich in amylin receptors. Subsequent to the activation of AP neurons, the neural signal is conveyed to the forebrain via relays involving the nucleus of the solitary tract (NTS) and the lateral parabrachial nucleus (lPBN) to the lateral hypothalamic area (LHA) and other hypothalamic nuclei. While the NTS and lPBN seem to be necessary for amylin's eating inhibitory effect, the role of the LHA has not yet been fully investigated. Amylin may also act as an adiposity signal. Plasma levels of amylin are higher in obese individuals, and chronic infusion of amylin into the brain reduces body weight gain and adiposity; chronic infusion of an amylin receptor antagonist into the brain increases body adiposity. Amylin increases energy expenditure in rats; this effect occurs under various experimental conditions after peripheral and central administration. Together, these animal data, but also clinical data in humans, indicate that amylin is a promising candidate for the treatment of obesity; effects are most pronounced when amylin is combined with leptin. Finally, recent findings indicate that amylin acts as a neurotrophic factor in specific brain stem areas. Whether this effect may be relevant under physiological conditions requires further studies.
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Affiliation(s)
- Thomas A Lutz
- Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland.
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Patil SM, Xu S, Sheftic SR, Alexandrescu AT. Dynamic alpha-helix structure of micelle-bound human amylin. J Biol Chem 2009; 284:11982-91. [PMID: 19244249 DOI: 10.1074/jbc.m809085200] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Amylin is an endocrine hormone that regulates metabolism. In patients afflicted with type 2 diabetes, amylin is found in fibrillar deposits in the pancreas. Membranes are thought to facilitate the aggregation of amylin, and membrane-bound oligomers may be responsible for the islet beta-cell toxicity that develops during type 2 diabetes. To better understand the structural basis for the interactions between amylin and membranes, we determined the NMR structure of human amylin bound to SDS micelles. The first four residues in the structure are constrained to form a hairpin loop by the single disulfide bond in amylin. The last nine residues near the C terminus are unfolded. The core of the structure is an alpha-helix that runs from about residues 5-28. A distortion or kink near residues 18-22 introduces pliancy in the angle between the N- and C-terminal segments of the alpha-helix. Mobility, as determined by (15)N relaxation experiments, increases from the N to the C terminus and is strongly correlated with the accessibility of the polypeptide to spin probes in the solution phase. The spin probe data suggest that the segment between residues 5 and 17 is positioned within the hydrophobic lipid environment, whereas the amyloidogenic segment between residues 20 and 29 is at the interface between the lipid and solvent. This orientation may direct the aggregation of amylin on membranes, whereas coupling between the two segments may mediate the transition to a toxic structure.
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Affiliation(s)
- Sharadrao M Patil
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269-3125, USA
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Su H, He M, Li H, Liu Q, Wang J, Wang Y, Gao W, Zhou L, Liao J, Young AA, Wang MW. Boc5, a non-peptidic glucagon-like Peptide-1 receptor agonist, invokes sustained glycemic control and weight loss in diabetic mice. PLoS One 2008; 3:e2892. [PMID: 18682834 PMCID: PMC2483413 DOI: 10.1371/journal.pone.0002892] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Accepted: 07/15/2008] [Indexed: 12/25/2022] Open
Abstract
Background Our recent discovery of the substituted cyclobutane Boc5, one of the first non-peptidic agonists at glucagon-like peptide-1 receptors, offers the potential of combining oral availability with full agonism capable of eliciting antidiabetic and antiobesity effects. The present study was aimed at determining the in vivo pharmacologic properties of Boc5 in both normal and diabetic mice following chronic administration, with emphasis on glycemic control and weight loss. Methodology/Principal Findings C57BL/6J and db/db mice were treated daily with Boc5 for 4 weeks and a range of pharmacologic parameters, including hemoglobin A1c, intraperitoneal glucose tolerance, insulin tolerance, fasting insulin and leptin levels, food intake, body weight and fat mass, were assessed before and after the treatment. Effects on food intake, gastric emptying, and insulinogenic index were also investigated in animals acutely administered with Boc5. Boc5 (3 mg) was able to induce a durable restoration of glycemic control (normalization of both hemoglobin A1c and intraperitoneal glucose tolerance) in db/db mice, following 4 weeks of daily administration. As with peptidic glucagon-like peptide-1 receptor agonists, its glycemic benefit and weight (fat) loss were associated with dose-dependent effects that included reduction in food intake, slowing of gastric emptying (both of which reduce nutrient-drive at β-cells), stimulation of insulin secretion (which was glucose-dependent), and elevation in insulin sensitivity. There was little effect on normal mice treated in the same manner. Conclusions/Significance Our findings suggest that Boc5 is the only non-peptidic molecule reported thus far to simultaneously activate this spectrum of antidiabetic effects.
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Affiliation(s)
- Haoran Su
- The National Center for Drug Screening, Shanghai, China
| | - Min He
- The National Center for Drug Screening, Shanghai, China
| | - Hongmei Li
- The National Center for Drug Screening, Shanghai, China
| | - Qing Liu
- The National Center for Drug Screening, Shanghai, China
- The State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Jia Wang
- The National Center for Drug Screening, Shanghai, China
| | - Yiqian Wang
- The National Center for Drug Screening, Shanghai, China
| | - Weiwei Gao
- The National Center for Drug Screening, Shanghai, China
| | - Ling Zhou
- The National Center for Drug Screening, Shanghai, China
| | - Jiayu Liao
- The National Center for Drug Screening, Shanghai, China
| | | | - Ming-Wei Wang
- The National Center for Drug Screening, Shanghai, China
- The State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- * E-mail:
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Bello NT, Kemm MH, Moran TH. Salmon calcitonin reduces food intake through changes in meal sizes in male rhesus monkeys. Am J Physiol Regul Integr Comp Physiol 2008; 295:R76-81. [PMID: 18480241 DOI: 10.1152/ajpregu.90327.2008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Amylinergic mechanisms are believed to be involved in the control of appetite. This study examined the effects of the amylin agonist, salmon calcitonin, on food intake and meal patterns in adult male rhesus monkeys. Fifteen minutes before the onset of their 6-h daily feeding period, monkeys received intramuscular injections of various doses of salmon calcitonin (0.032, 0.056, 0.1, 0.32, and 1 microg/kg) or saline. Salmon calcitonin dose dependently reduced total daily and hourly food intake, with significant decreases at the 0.1, 0.32, and 1 microg/kg doses. Daily food intake was reduced by approximately 35%, 62%, and 96%, at these doses, respectively. An analysis of meal patterns revealed that size of the first meal was significantly reduced across the dose range of 0.056 to 1 microg/kg, while average meal size was reduced with the 0.32 and 1 microg/kg doses. Meal number was only affected at the 1 microg/kg dose. Repeated 5-day administration of the 0.1 microg/kg dose resulted in a reduction in daily food intake only on injection day 2, while significant reductions in food intake were observed on all five injection days with a 0.32 microg/kg dose. Daily food intake was also reduced for 1 day after the termination of the 5-day injections of the 0.32 microg/kg salmon calcitonin dose. These sustained reductions in intake were expressed through decreases in meal size. These data demonstrate that salmon calcitonin acutely and consistently decreases food intake mainly through reductions in meal sizes in nonhuman primates.
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Affiliation(s)
- Nicholas T Bello
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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Michel S, Becskei C, Erguven E, Lutz TA, Riediger T. Diet-derived nutrients modulate the effects of amylin on c-Fos expression in the area postrema and on food intake. Neuroendocrinology 2007; 86:124-35. [PMID: 17703089 DOI: 10.1159/000107579] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 07/13/2007] [Indexed: 11/19/2022]
Abstract
The pancreatic hormone amylin decreases food intake via activation of area postrema (AP) neurons. We investigated whether amylin's potency to reduce food intake and to induce c-Fos expression in the AP/nucleus of the solitary tract region is affected by the feeding conditions and specifically by the macronutrient composition of the diet. Whereas a low dose of amylin (5 microg/kg s.c.) induced very little c-Fos expression in ad libitum chow fed rats, it caused a strong c-Fos expression in 24-hour food-deprived rats and in rats that received a nutrient-deficient non-caloric mash (NCM; vanilla-flavoured cellulose) 24 h before injection. To reveal the contribution of single nutrients to the low c-Fos expression after chow feeding, amylin-induced c-Fos was analyzed after feeding NCM that was selectively supplemented with glucose, fat (lard), or protein (casein), matching the intake of these nutrients of chow-fed rats. While the rats fed NCM supplemented with glucose or fat displayed an equally strong amylin-induced activation as fasted rats or rats fed plain NCM, a significantly lower c-Fos expression was observed in rats fed a protein-supplemented NCM or a NCM containing all three nutrients. In line with this lower activation, the same dose of amylin failed to reduce food intake in NCM/protein-fed rats, while amylin caused a reduction in feeding when animals received NCM, NCM/glucose, or NCM/fat. Interestingly, amylin effectively reduced food intake in ad libitum chow fed rats despite the low level of amylin-induced c-Fos expression in the AP under these conditions. We conclude that the anorectic potential of amylin may be attenuated by diet-derived proteins, whereas this effect appears to be overridden when the amount of carbohydrates/fat is high relative to the protein content, such as, e.g., in standard chow.
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Affiliation(s)
- Signe Michel
- Institute of Veterinary Physiology, University of Zürich, Zürich, Switzerland
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