1
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Roham PH, Save SN, Sharma S. Human islet amyloid polypeptide: A therapeutic target for the management of type 2 diabetes mellitus. J Pharm Anal 2022; 12:556-569. [PMID: 36105173 PMCID: PMC9463490 DOI: 10.1016/j.jpha.2022.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/21/2022] [Accepted: 04/01/2022] [Indexed: 12/22/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) and other metabolic disorders are often silent and go unnoticed in patients because of the lack of suitable prognostic and diagnostic markers. The current therapeutic regimens available for managing T2DM do not reverse diabetes; instead, they delay the progression of diabetes. Their efficacy (in principle) may be significantly improved if implemented at earlier stages. The misfolding and aggregation of human islet amyloid polypeptide (hIAPP) or amylin has been associated with a gradual decrease in pancreatic β-cell function and mass in patients with T2DM. Hence, hIAPP has been recognized as a therapeutic target for managing T2DM. This review summarizes hIAPP's role in mediating dysfunction and apoptosis in pancreatic β-cells via induction of endoplasmic reticulum stress, oxidative stress, mitochondrial dysfunction, inflammatory cytokine secretion, autophagy blockade, etc. Furthermore, it explores the possibility of using intermediates of the hIAPP aggregation pathway as potential drug targets for T2DM management. Finally, the effects of common antidiabetic molecules and repurposed drugs; other hIAPP mimetics and peptides; small organic molecules and natural compounds; nanoparticles, nanobodies, and quantum dots; metals and metal complexes; and chaperones that have demonstrated potential to inhibit and/or reverse hIAPP aggregation and can, therefore, be further developed for managing T2DM have been discussed. Misfolded species of hIAPP form toxic oligomers in pancreatic β-cells. hIAPP amyloids has been detected in the pancreas of about 90% subjects with T2DM. Inhibitors of hIAPP aggregation can help manage T2DM.
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2
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Kahn SE, Chen YC, Esser N, Taylor AJ, van Raalte DH, Zraika S, Verchere CB. The β Cell in Diabetes: Integrating Biomarkers With Functional Measures. Endocr Rev 2021; 42:528-583. [PMID: 34180979 PMCID: PMC9115372 DOI: 10.1210/endrev/bnab021] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Indexed: 02/08/2023]
Abstract
The pathogenesis of hyperglycemia observed in most forms of diabetes is intimately tied to the islet β cell. Impairments in propeptide processing and secretory function, along with the loss of these vital cells, is demonstrable not only in those in whom the diagnosis is established but typically also in individuals who are at increased risk of developing the disease. Biomarkers are used to inform on the state of a biological process, pathological condition, or response to an intervention and are increasingly being used for predicting, diagnosing, and prognosticating disease. They are also proving to be of use in the different forms of diabetes in both research and clinical settings. This review focuses on the β cell, addressing the potential utility of genetic markers, circulating molecules, immune cell phenotyping, and imaging approaches as biomarkers of cellular function and loss of this critical cell. Further, we consider how these biomarkers complement the more long-established, dynamic, and often complex measurements of β-cell secretory function that themselves could be considered biomarkers.
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Affiliation(s)
- Steven E Kahn
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, 98108 WA, USA
| | - Yi-Chun Chen
- BC Children's Hospital Research Institute and Centre for Molecular Medicine and Therapeutics, Vancouver, BC, V5Z 4H4, Canada.,Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, V5Z 4H4, Canada.,Department of Surgery, University of British Columbia, Vancouver, BC, V5Z 4H4, Canada
| | - Nathalie Esser
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, 98108 WA, USA
| | - Austin J Taylor
- BC Children's Hospital Research Institute and Centre for Molecular Medicine and Therapeutics, Vancouver, BC, V5Z 4H4, Canada.,Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, V5Z 4H4, Canada.,Department of Surgery, University of British Columbia, Vancouver, BC, V5Z 4H4, Canada
| | - Daniël H van Raalte
- Department of Internal Medicine, Amsterdam University Medical Center (UMC), Vrije Universiteit (VU) University Medical Center, 1007 MB Amsterdam, The Netherlands.,Department of Experimental Vascular Medicine, Amsterdam University Medical Center (UMC), Academic Medical Center, 1007 MB Amsterdam, The Netherlands
| | - Sakeneh Zraika
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, 98108 WA, USA
| | - C Bruce Verchere
- BC Children's Hospital Research Institute and Centre for Molecular Medicine and Therapeutics, Vancouver, BC, V5Z 4H4, Canada.,Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, V5Z 4H4, Canada.,Department of Surgery, University of British Columbia, Vancouver, BC, V5Z 4H4, Canada
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3
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Nguyen PH, Ramamoorthy A, Sahoo BR, Zheng J, Faller P, Straub JE, Dominguez L, Shea JE, Dokholyan NV, De Simone A, Ma B, Nussinov R, Najafi S, Ngo ST, Loquet A, Chiricotto M, Ganguly P, McCarty J, Li MS, Hall C, Wang Y, Miller Y, Melchionna S, Habenstein B, Timr S, Chen J, Hnath B, Strodel B, Kayed R, Lesné S, Wei G, Sterpone F, Doig AJ, Derreumaux P. Amyloid Oligomers: A Joint Experimental/Computational Perspective on Alzheimer's Disease, Parkinson's Disease, Type II Diabetes, and Amyotrophic Lateral Sclerosis. Chem Rev 2021; 121:2545-2647. [PMID: 33543942 PMCID: PMC8836097 DOI: 10.1021/acs.chemrev.0c01122] [Citation(s) in RCA: 368] [Impact Index Per Article: 122.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein misfolding and aggregation is observed in many amyloidogenic diseases affecting either the central nervous system or a variety of peripheral tissues. Structural and dynamic characterization of all species along the pathways from monomers to fibrils is challenging by experimental and computational means because they involve intrinsically disordered proteins in most diseases. Yet understanding how amyloid species become toxic is the challenge in developing a treatment for these diseases. Here we review what computer, in vitro, in vivo, and pharmacological experiments tell us about the accumulation and deposition of the oligomers of the (Aβ, tau), α-synuclein, IAPP, and superoxide dismutase 1 proteins, which have been the mainstream concept underlying Alzheimer's disease (AD), Parkinson's disease (PD), type II diabetes (T2D), and amyotrophic lateral sclerosis (ALS) research, respectively, for many years.
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Affiliation(s)
- Phuong H Nguyen
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Bikash R Sahoo
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Jie Zheng
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Peter Faller
- Institut de Chimie, UMR 7177, CNRS-Université de Strasbourg, 4 rue Blaise Pascal, 67000 Strasbourg, France
| | - John E Straub
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Laura Dominguez
- Facultad de Química, Departamento de Fisicoquímica, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - Nikolay V Dokholyan
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
- Department of Chemistry, and Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Alfonso De Simone
- Department of Life Sciences, Imperial College London, London SW7 2AZ, U.K
- Molecular Biology, University of Naples Federico II, Naples 80138, Italy
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Saeed Najafi
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - Son Tung Ngo
- Laboratory of Theoretical and Computational Biophysics & Faculty of Applied Sciences, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
| | - Antoine Loquet
- Institute of Chemistry & Biology of Membranes & Nanoobjects, (UMR5248 CBMN), CNRS, Université Bordeaux, Institut Européen de Chimie et Biologie, 33600 Pessac, France
| | - Mara Chiricotto
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester M13 9PL, U.K
| | - Pritam Ganguly
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - James McCarty
- Chemistry Department, Western Washington University, Bellingham, Washington 98225, United States
| | - Mai Suan Li
- Institute for Computational Science and Technology, SBI Building, Quang Trung Software City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City 700000, Vietnam
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Carol Hall
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Yiming Wang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Yifat Miller
- Department of Chemistry and The Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
| | | | - Birgit Habenstein
- Institute of Chemistry & Biology of Membranes & Nanoobjects, (UMR5248 CBMN), CNRS, Université Bordeaux, Institut Européen de Chimie et Biologie, 33600 Pessac, France
| | - Stepan Timr
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Jiaxing Chen
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
| | - Brianna Hnath
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rakez Kayed
- Mitchell Center for Neurodegenerative Diseases, and Departments of Neurology, Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Sylvain Lesné
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Guanghong Wei
- Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Science, Multiscale Research Institute of Complex Systems, Fudan University, Shanghai 200438, China
| | - Fabio Sterpone
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Andrew J Doig
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, U.K
| | - Philippe Derreumaux
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
- Laboratory of Theoretical Chemistry, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
- Faculty of Pharmacy, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
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4
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Bishoyi AK, Roham PH, Rachineni K, Save S, Hazari MA, Sharma S, Kumar A. Human islet amyloid polypeptide (hIAPP) - a curse in type II diabetes mellitus: insights from structure and toxicity studies. Biol Chem 2020; 402:133-153. [PMID: 33544470 DOI: 10.1515/hsz-2020-0174] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/11/2020] [Indexed: 12/13/2022]
Abstract
The human islet amyloid polypeptide (hIAPP) or amylin, a neuroendocrine peptide hormone, is known to misfold and form amyloidogenic aggregates that have been observed in the pancreas of 90% subjects with Type 2 Diabetes Mellitus (T2DM). Under normal physiological conditions, hIAPP is co-stored and co-secreted with insulin; however, under chronic hyperglycemic conditions associated with T2DM, the overexpression of hIAPP occurs that has been associated with the formation of amyloid deposits; as well as the death and dysfunction of pancreatic β-islets in T2DM. Hitherto, various biophysical and structural studies have shown that during this process of aggregation, the peptide conformation changes from random structure to helix, then to β-sheet, subsequently to cross β-sheets, which finally form left-handed helical aggregates. The intermediates, formed during this process, have been shown to induce higher cytotoxicity in the β-cells by inducing cell membrane disruption, endoplasmic reticulum stress, mitochondrial dysfunction, oxidative stress, islet inflammation, and DNA damage. As a result, several research groups have attempted to target both hIAPP aggregation phenomenon and the destabilization of preformed fibrils as a therapeutic intervention for T2DM management. In this review, we have summarized structural aspects of various forms of hIAPP viz. monomer, oligomers, proto-filaments, and fibrils of hIAPP. Subsequently, cellular toxicity caused by toxic conformations of hIAPP has been elaborated upon. Finally, the need for performing structural and toxicity studies in vivo to fill in the gap between the structural and cellular aspects has been discussed.
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Affiliation(s)
- Ajit Kumar Bishoyi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
| | - Pratiksha H Roham
- Department of Biotechnology, Savitribai Phule Pune University (Formerly University of Pune), Ganeshkhind, Pune, 411007, Maharashtra, India
| | - Kavitha Rachineni
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
| | - Shreyada Save
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
| | - M Asrafuddoza Hazari
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
| | - Shilpy Sharma
- Department of Biotechnology, Savitribai Phule Pune University (Formerly University of Pune), Ganeshkhind, Pune, 411007, Maharashtra, India
| | - Ashutosh Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
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5
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Berardet C, Kaffy J, Halgand F, Van der Rest G, Ongeri S, Taverna M. Evidence for different in vitro oligomerization behaviors of synthetic hIAPP obtained from different sources. Anal Bioanal Chem 2020; 412:3103-3111. [PMID: 32211924 DOI: 10.1007/s00216-020-02560-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/07/2020] [Accepted: 02/28/2020] [Indexed: 12/15/2022]
Abstract
Type 2 diabetes is characterized by the aggregation of human islet amyloid polypeptide (hIAPP), from monomer to amyloid deposits that are made of insoluble fibrils. Discrepancies concerning the nature of formed species or oligomerization kinetics among reported in vitro studies on hIAPP aggregation process have been highlighted. In this work, we investigated if the sample itself could be at the origin of those observed differences. To this aim, four hIAPP samples obtained from three different sources or suppliers have been analyzed and compared by ThT fluorescence spectroscopy and by two recently developed techniques, capillary electrophoresis (CE), and ESI-IMS-QToF-MS. Lots provided by the same supplier were shown to be very similar whatever the analytical technique used to characterize them. In contrast, several critical differences could be pointed out for hIAPP provided by different suppliers. We demonstrated that in several samples, some oligomerized peptides (e.g., dimer) were already present upon reception. Purity was also different, and the proneness of the peptide solution to form fibrils in vitro within 24 h could vary considerably from one sample source to another but not from lot to lot of the same source. All those results demonstrate that the initial state of conformation, oligomerization, and quality of the hIAPP can greatly impact the aggregation kinetics, and thus the information provided by these in vitro tests. Finally, a careful selection of the peptide batch and source is mandatory to perform relevant in vitro studies on hIAPP oligomerization and to screen new molecules modulating this pathological process. Graphical abstract.
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Affiliation(s)
- Corentin Berardet
- CNRS, Institut Galien Paris Sud, Université Paris-Saclay, 92296, Châtenay-Malabry, France.,CNRS, BioCIS, FLUOPEPIT, Université Paris-Saclay, 92290, Châtenay-Malabry, France
| | - Julia Kaffy
- CNRS, BioCIS, FLUOPEPIT, Université Paris-Saclay, 92290, Châtenay-Malabry, France
| | - Frédéric Halgand
- Institut de Chimie Physique, UMR 8000, Réactivité des Ions, Spectrométrie de Masse, Analyse et Spectroscopies (RISMAS), CNRS, University Paris-Sud, University Paris-Saclay, Rue Henri Becquerel, Bâtiment 201 P2, 91405, Orsay, France
| | - Guillaume Van der Rest
- Institut de Chimie Physique, UMR 8000, Réactivité des Ions, Spectrométrie de Masse, Analyse et Spectroscopies (RISMAS), CNRS, University Paris-Sud, University Paris-Saclay, Rue Henri Becquerel, Bâtiment 201 P2, 91405, Orsay, France
| | - Sandrine Ongeri
- CNRS, BioCIS, FLUOPEPIT, Université Paris-Saclay, 92290, Châtenay-Malabry, France
| | - Myriam Taverna
- CNRS, Institut Galien Paris Sud, Université Paris-Saclay, 92296, Châtenay-Malabry, France. .,Institut Universitaire de France, Paris, France.
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6
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DeLisle CF, Malooley AL, Banerjee I, Lorieau JL. Pro-islet amyloid polypeptide in micelles contains a helical prohormone segment. FEBS J 2020; 287:4440-4457. [PMID: 32077246 DOI: 10.1111/febs.15253] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 01/17/2020] [Accepted: 02/18/2020] [Indexed: 12/31/2022]
Abstract
Pro-islet amyloid polypeptide (proIAPP) is the prohormone precursor molecule to IAPP, also known as amylin. IAPP is a calcitonin family peptide hormone that is cosecreted with insulin, and largely responsible for hunger satiation and metabolic homeostasis. Amyloid plaques containing mixtures of mature IAPP and misprocessed proIAPP deposit on, and destroy pancreatic β-cell membranes, and they are recognized as a clinical hallmark of type 2 diabetes mellitus. In order to better understand the interaction with cellular membranes, we solved the solution NMR structure of proIAPP bound to dodecylphosphocholine micelles at pH 4.5. We show that proIAPP is a dynamic molecule with four α-helices. The first two helices are contained within the mature IAPP sequence, while the second two helices are part of the C-terminal prohormone segment (Cpro). We mapped the membrane topology of the amphipathic helices by paramagnetic relaxation enhancement, and we used CD and diffusion-ordered spectroscopy to identify environmental factors that impact proIAPP membrane affinity. We discuss how our structural results relate to prohormone processing based on the varied pH environments and lipid compositions of organelle membranes within the regulated secretory pathway, and the likelihood of Cpro survival for cosecretion with IAPP. DATABASE: The assigned resonances have been deposited in the Biological Magnetic Resonance Bank (BMRB) with accession numbers 50007 and 50019 for proIAPP and Cpro, respectively. The lowest energy structures have been deposited in the Protein Data Bank (PDB) with access codes 6UCJ and 6UCK.
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Affiliation(s)
- Charles F DeLisle
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, USA
| | | | - Indrani Banerjee
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, USA
| | - Justin L Lorieau
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL, USA
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7
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Grandl G, Novikoff A, DiMarchi R, Tschöp MH, Müller TD. Gut Peptide Agonism in the Treatment of Obesity and Diabetes. Compr Physiol 2019; 10:99-124. [PMID: 31853954 DOI: 10.1002/cphy.c180044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Obesity is a global healthcare challenge that gives rise to devastating diseases such as the metabolic syndrome, type-2 diabetes (T2D), and a variety of cardiovascular diseases. The escalating prevalence of obesity has led to an increased interest in pharmacological options to counteract excess weight gain. Gastrointestinal hormones such as glucagon, amylin, and glucagon-like peptide-1 (GLP-1) are well recognized for influencing food intake and satiety, but the therapeutic potential of these native peptides is overall limited by a short half-life and an often dose-dependent appearance of unwanted effects. Recent clinical success of chemically optimized GLP-1 mimetics with improved pharmacokinetics and sustained action has propelled pharmacological interest in using bioengineered gut hormones to treat obesity and diabetes. In this article, we summarize the basic biology and signaling mechanisms of selected gut peptides and discuss how they regulate systemic energy and glucose metabolism. Subsequently, we focus on the design and evaluation of unimolecular drugs that combine the beneficial effects of selected gut hormones into a single entity to optimize the beneficial impact on systems metabolism. © 2020 American Physiological Society. Compr Physiol 10:99-124, 2020.
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Affiliation(s)
- Gerald Grandl
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Aaron Novikoff
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Richard DiMarchi
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
| | - Matthias H Tschöp
- German Center for Diabetes Research (DZD), Neuherberg, Germany.,Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München - German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany.,Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany
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8
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IAPP in type II diabetes: Basic research on structure, molecular interactions, and disease mechanisms suggests potential intervention strategies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018. [DOI: 10.1016/j.bbamem.2018.02.020] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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9
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Bliss ES, Whiteside E. The Gut-Brain Axis, the Human Gut Microbiota and Their Integration in the Development of Obesity. Front Physiol 2018; 9:900. [PMID: 30050464 PMCID: PMC6052131 DOI: 10.3389/fphys.2018.00900] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/21/2018] [Indexed: 12/17/2022] Open
Abstract
Obesity is a global epidemic, placing socioeconomic strain on public healthcare systems, especially within the so-called Western countries, such as Australia, United States, United Kingdom, and Canada. Obesity results from an imbalance between energy intake and energy expenditure, where energy intake exceeds expenditure. Current non-invasive treatments lack efficacy in combating obesity, suggesting that obesity is a multi-faceted and more complex disease than previously thought. This has led to an increase in research exploring energy homeostasis and the discovery of a complex bidirectional communication axis referred to as the gut-brain axis. The gut-brain axis is comprised of various neurohumoral components that allow the gut and brain to communicate with each other. Communication occurs within the axis via local, paracrine and/or endocrine mechanisms involving a variety of gut-derived peptides produced from enteroendocrine cells (EECs), including glucagon-like peptide 1 (GLP1), cholecystokinin (CCK), peptide YY3-36 (PYY), pancreatic polypeptide (PP), and oxyntomodulin. Neural networks, such as the enteric nervous system (ENS) and vagus nerve also convey information within the gut-brain axis. Emerging evidence suggests the human gut microbiota, a complex ecosystem residing in the gastrointestinal tract (GIT), may influence weight-gain through several inter-dependent pathways including energy harvesting, short-chain fatty-acids (SCFA) signalling, behaviour modifications, controlling satiety and modulating inflammatory responses within the host. Hence, the gut-brain axis, the microbiota and the link between these elements and the role each plays in either promoting or regulating energy and thereby contributing to obesity will be explored in this review.
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Affiliation(s)
- Edward S. Bliss
- School of Health and Wellbeing, University of Southern Queensland, Toowoomba, QLD, Australia
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10
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Abdelwhab SM, Shehata OZ, El Magd YA, Kamal A. Serum amylin level in Behçet’s disease and relation to parameters of metabolic syndrome and disease activity. EGYPTIAN RHEUMATOLOGY AND REHABILITATION 2018. [DOI: 10.4103/err.err_42_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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11
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Raleigh D, Zhang X, Hastoy B, Clark A. The β-cell assassin: IAPP cytotoxicity. J Mol Endocrinol 2017; 59:R121-R140. [PMID: 28811318 DOI: 10.1530/jme-17-0105] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 08/15/2017] [Indexed: 12/28/2022]
Abstract
Islet amyloid polypeptide (IAPP) forms cytotoxic oligomers and amyloid fibrils in islets in type 2 diabetes (T2DM). The causal factors for amyloid formation are largely unknown. Mechanisms of molecular folding and assembly of human IAPP (hIAPP) into β-sheets, oligomers and fibrils have been assessed by detailed biophysical studies of hIAPP and non-fibrillogenic, rodent IAPP (rIAPP); cytotoxicity is associated with the early phases (oligomers/multimers) of fibrillogenesis. Interaction with synthetic membranes promotes β-sheet assembly possibly via a transient α-helical molecular conformation. Cellular hIAPP cytotoxicity can be activated from intracellular or extracellular sites. In transgenic rodents overexpressing hIAPP, intracellular pro-apoptotic signals can be generated at different points in β-cell protein synthesis. Increased cellular trafficking of proIAPP, failure of the unfolded protein response (UPR) or excess trafficking of misfolded peptide via the degradation pathways can induce apoptosis; these data indicate that defects in intracellular handling of hIAPP can induce cytotoxicity. However, there is no evidence for IAPP overexpression in T2DM. Extracellular amyloidosis is directly related to the degree of β-cell apoptosis in islets in T2DM. IAPP fragments, fibrils and multimers interact with membranes causing disruption in vivo and in vitro These findings support a role for extracellular IAPP in β-sheet conformation in cytotoxicity. Inhibitors of fibrillogenesis are useful tools to determine the aberrant mechanisms that result in hIAPP molecular refolding and islet amyloidosis. However, currently, their role as therapeutic agents remains uncertain.
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Affiliation(s)
- Daniel Raleigh
- Department of ChemistryStony Brook University, Stony Brook, New York, USA
- Research Department of Structural and Molecule BiologyUniversity College London, London, UK
| | - Xiaoxue Zhang
- Department of ChemistryStony Brook University, Stony Brook, New York, USA
| | - Benoît Hastoy
- Oxford Centre for Diabetes Endocrinology and MetabolismUniversity of Oxford, Oxford, UK
| | - Anne Clark
- Oxford Centre for Diabetes Endocrinology and MetabolismUniversity of Oxford, Oxford, UK
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Guardado-Mendoza R, Chávez AO, Jiménez-Ceja LM, Hansis-Diarte A, DeFronzo RA, Folli F, Tripathy D. Islet amyloid polypeptide response to maximal hyperglycemia and arginine is altered in impaired glucose tolerance and type 2 diabetes mellitus. Acta Diabetol 2017; 54:53-61. [PMID: 27624579 DOI: 10.1007/s00592-016-0904-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 08/18/2016] [Indexed: 12/29/2022]
Abstract
AIMS Pancreatic islet amyloid deposition is a characteristic feature of type 2 diabetes mellitus (T2DM). Islet amyloid polypeptide (IAPP) is co-secreted with insulin, but its secretion profile and relationship to insulin and C-peptide in response to glucose and non-glucose stimuli has not been clearly defined. METHODS Forty subjects (13 NGT, 12 IGT and 15 T2DM) participated in an OGTT and two-step hyperglycemic (225 and 400 mg/dl) clamp (80 min/step) followed by an IV arginine bolus. Acute insulin (AIR), C-peptide (ACPR) and IAPP (AIAR) responses during each hyperglycemic step and following arginine (AIRArg) were assessed. RESULTS AIR and ACPR during both hyperglycemic steps and after arginine progressively decreased from NGT to IGT to T2DM. Fasting IAPP concentrations were higher in T2DM compared to NGT and IGT subjects. The acute IAPP0-10 was markedly decreased only in T2DM, while the acute IAPP80-90 response during the second step (80-160 min) of hyperglycemic clamp and in response to arginine was markedly impaired in both IGT and T2DM. The ratio of IAPP/C-peptide during the first (225 mg/dl) and second step (400 mg/dl), and in response to arginine, was decreased in T2DM versus both NGT and IGT (p < 0.01). The acute IAPP0-10 correlated with ACPR0-10 (r = 0.665, p < 0.001) and AIR0-10 (r = 0.543, p < 0.001). CONCLUSIONS Basal IAPP secretion is higher in T2DM and IGT versus NGT but is reduced in response to hyperglycemia and arginine. The IAPP/C-peptide ratio is reduced with prolonged and more severe hyperglycemia in T2DM individuals. CLINICAL TRIAL REGISTRATION NCT00845182.
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Affiliation(s)
- Rodolfo Guardado-Mendoza
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA
- Division of Health Sciences, Department of Medicine and Nutrition, University of Guanajuato, Guanajuato, Mexico
- Departamento de Investigación, Hospital Regional de Alta Especialidad del Bajío, Guanajuato, Mexico
| | - Alberto O Chávez
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA
| | - Lilia M Jiménez-Ceja
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA
- Division of Health Sciences, Department of Medicine and Nutrition, University of Guanajuato, Guanajuato, Mexico
- Departamento de Investigación, Hospital Regional de Alta Especialidad del Bajío, Guanajuato, Mexico
| | - Andrea Hansis-Diarte
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA
| | - Ralph A DeFronzo
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA
- Audie L Murphy VA Hospital, South Texas Veteran Health Care System, San Antonio, TX, USA
| | - Franco Folli
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA
| | - Devjit Tripathy
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA.
- Audie L Murphy VA Hospital, South Texas Veteran Health Care System, San Antonio, TX, USA.
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13
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Delong T, Wiles TA, Baker RL, Bradley B, Barbour G, Reisdorph R, Armstrong M, Powell RL, Reisdorph N, Kumar N, Elso CM, DeNicola M, Bottino R, Powers AC, Harlan DM, Kent SC, Mannering SI, Haskins K. Pathogenic CD4 T cells in type 1 diabetes recognize epitopes formed by peptide fusion. Science 2016; 351:711-4. [PMID: 26912858 DOI: 10.1126/science.aad2791] [Citation(s) in RCA: 350] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
T cell-mediated destruction of insulin-producing β cells in the pancreas causes type 1 diabetes (T1D). CD4 T cell responses play a central role in β cell destruction, but the identity of the epitopes recognized by pathogenic CD4 T cells remains unknown. We found that diabetes-inducing CD4 T cell clones isolated from nonobese diabetic mice recognize epitopes formed by covalent cross-linking of proinsulin peptides to other peptides present in β cell secretory granules. These hybrid insulin peptides (HIPs) are antigenic for CD4 T cells and can be detected by mass spectrometry in β cells. CD4 T cells from the residual pancreatic islets of two organ donors who had T1D also recognize HIPs. Autoreactive T cells targeting hybrid peptides may explain how immune tolerance is broken in T1D.
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Affiliation(s)
- Thomas Delong
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Denver, Anschutz Medical Campus, Aurora, CO 80045, USA.
| | - Timothy A Wiles
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Rocky L Baker
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Brenda Bradley
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Gene Barbour
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Richard Reisdorph
- Pharmaceutical Sciences, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Michael Armstrong
- Pharmaceutical Sciences, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Roger L Powell
- Pharmaceutical Sciences, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Nichole Reisdorph
- Pharmaceutical Sciences, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Nitesh Kumar
- Immunology and Diabetes Unit, St. Vincent's Institute of Medical Research, 9 Princes Street, Fitzroy, Victoria 3065, Australia
| | - Colleen M Elso
- Immunology and Diabetes Unit, St. Vincent's Institute of Medical Research, 9 Princes Street, Fitzroy, Victoria 3065, Australia
| | - Megan DeNicola
- Department of Medicine, Diabetes Division, Diabetes Center of Excellence, University of Massachusetts Medical School, Worcester, MA, USA
| | - Rita Bottino
- Institute of Cellular Therapeutics, Allegheny-Singer Research Institute, Allegheny Health Network, Pittsburgh, PA, USA
| | - Alvin C Powers
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, and Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN, USA. VA Tennessee Valley Healthcare System, Nashville, TN, USA
| | - David M Harlan
- Department of Medicine, Diabetes Division, Diabetes Center of Excellence, University of Massachusetts Medical School, Worcester, MA, USA
| | - Sally C Kent
- Department of Medicine, Diabetes Division, Diabetes Center of Excellence, University of Massachusetts Medical School, Worcester, MA, USA
| | - Stuart I Mannering
- Immunology and Diabetes Unit, St. Vincent's Institute of Medical Research, 9 Princes Street, Fitzroy, Victoria 3065, Australia. University of Melbourne, Department of Medicine, St. Vincent's Hospital, Fitzroy, Victoria 3065, Australia
| | - Kathryn Haskins
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Denver, Anschutz Medical Campus, Aurora, CO 80045, USA.
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14
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Wang J, Xiao R. G protein-coupled receptors in energy homeostasis. SCIENCE CHINA-LIFE SCIENCES 2014; 57:672-80. [PMID: 24969703 DOI: 10.1007/s11427-014-4694-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 06/13/2014] [Indexed: 12/25/2022]
Abstract
G-protein coupled receptors (GPCRs) compromise the largest membrane protein superfamily which play vital roles in physiological and pathophysiological processes including energy homeostasis. Moreover, they also represent the up-to-date most successful drug target. The gut hormone GPCRs, such as glucagon receptor and GLP-1 receptor, have been intensively studied for their roles in metabolism and respective drugs have developed for the treatment of metabolic diseases such as type 2 diabetes (T2D). Along with the advances of biomedical research, more GPCRs have been found to play important roles in the regulation of energy homeostasis from nutrient sensing, appetite control to glucose and fatty acid metabolism with various mechanisms. The investigation of their biological functions will not only improve our understanding of how our body keeps the balance of energy intake and expenditure, but also highlight the possible drug targets for the treatment of metabolic diseases. The present review summarizes GPCRs involved in the energy control with special emphasis on their pathophysiological roles in metabolic diseases and hopefully triggers more intensive and systematic investigations in the field so that a comprehensive network control of energy homeostasis will be revealed, and better drugs will be developed in the foreseeable future.
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Affiliation(s)
- Jue Wang
- Institute of Molecular Medicine, Peking University, Beijing, 100871, China,
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15
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Abstract
Over the past 30 years, it has been established that hormones produced by the gut, pancreas, and adipose tissue are key players in the control of body weight. These hormones act through a complex neuroendocrine system, including the hypothalamus, to regulate metabolism and energy homeostasis. In obesity, this homeostatic balance is disrupted, either through alterations in the levels of these hormones or through resistance to their actions. Alterations in gut hormone secretion following gastric bypass surgery are likely to underlie the dramatic and persistent loss of weight following this procedure, as well as the observed amelioration in type 2 diabetes mellitus. Medications based on the gut hormone GLP-1 are currently in clinical use to treat type 2 diabetes mellitus and have been shown to produce weight loss. Further therapies for obesity based on other gut hormones are currently in development.
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Affiliation(s)
- Rebecca Scott
- Division of Diabetes, Endocrinology, Metabolism, Hammersmith Hospital, Imperial College London, London, United Kingdom.
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16
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Watve M, Bodas A, Diwekar M. Altered autonomic inputs as a cause of pancreatic β-cell amyloid. Med Hypotheses 2013; 82:49-53. [PMID: 24321738 DOI: 10.1016/j.mehy.2013.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/03/2013] [Indexed: 01/09/2023]
Abstract
A partial loss of β-cell mass and β-cell dysfunction in Type 2 Diabetes Mellitus (T2DM) is associated with amyloid deposition but whether it is causal or consequential is debated. Although the in vitro polymerization of amylin has been studied in detail, the exact trigger for the mechanism in vivo has not been identified. One suggestion is that an increased load on β-cells results in inefficient handling of proteins leading to misfolding and aggregation, but this hypothesis is faced with certain paradoxes. We suggest an alternative mechanism based on the assumption that polymerization is a spontaneous process. The concentration of the polypeptide in β-cell granules is shown to be sufficient to allow polymerization. However if the rate of turnover in normal cells is greater than the rate of polymerization, amyloid deposition will not be observed. If this is true, it follows that amyloid deposition could be a result of increased retention time of amylin in the β-cell granules. In T2D, the sympathetic inputs are known to increase which could result in suppression of the secretion process. The increase in the retention time due to this suppression can allow polymerization. In addition to this in a prediabetic state parasympathetic stimulation increases β-cell proliferation. This reduces the insulin demand per cell thereby increasing the mean retention time. Thus a combination of contrasting actions of sympathetic and parasympathetic systems could lead to increase in the amyloid deposition. We suggest testable predictions of the alternative hypotheses and the lines of research needed to test them.
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Affiliation(s)
- Milind Watve
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
| | - Arushi Bodas
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Manawa Diwekar
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
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17
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Abstract
Gut microbiota is an assortment of microorganisms inhabiting the length and width of the mammalian gastrointestinal tract. The composition of this microbial community is host specific, evolving throughout an individual's lifetime and susceptible to both exogenous and endogenous modifications. Recent renewed interest in the structure and function of this "organ" has illuminated its central position in health and disease. The microbiota is intimately involved in numerous aspects of normal host physiology, from nutritional status to behavior and stress response. Additionally, they can be a central or a contributing cause of many diseases, affecting both near and far organ systems. The overall balance in the composition of the gut microbial community, as well as the presence or absence of key species capable of effecting specific responses, is important in ensuring homeostasis or lack thereof at the intestinal mucosa and beyond. The mechanisms through which microbiota exerts its beneficial or detrimental influences remain largely undefined, but include elaboration of signaling molecules and recognition of bacterial epitopes by both intestinal epithelial and mucosal immune cells. The advances in modeling and analysis of gut microbiota will further our knowledge of their role in health and disease, allowing customization of existing and future therapeutic and prophylactic modalities.
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Affiliation(s)
- Inna Sekirov
- Michael Smith Laboratories, Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada
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18
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Davalli AM, Perego L, Bertuzzi F, Finzi G, La Rosa S, Blau A, Placidi C, Nano R, Gregorini L, Perego C, Capella C, Folli F. Disproportionate hyperproinsulinemia, beta-cell restricted prohormone convertase 2 deficiency, and cell cycle inhibitors expression by human islets transplanted into athymic nude mice: insights into nonimmune-mediated mechanisms of delayed islet graft failure. Cell Transplant 2009; 17:1323-36. [PMID: 19364070 DOI: 10.3727/096368908787648137] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
To learn more about nonimmune-mediated islet graft failure, we transplanted different preparations (preps) of isolated human islets under the kidney capsule of streptozotocin (STZ)-diabetic nude mice. One month after the implantation of 1,000 or 2,000 islets, grafts were harvested for morphological, immunohistochemical, and ultrastructural analysis. Only a single islet prep cured the diabetes out of all the recipients, while the remaining preps showed only partial function after the implantation of 2,000 islets. Transplanted mice showed high circulating proinsulin levels but, with the exclusion of those bearing curative grafts, relatively low mature insulin levels. Engrafted beta-cells showed positive carboxypeptidase E (CPE) and prohormone convertase 1 (PC1) staining, while prohormone convertase 2 (PC2) was undetectable. In contrast, PC2 was abundantly expressed by engrafted alpha-cells. Moreover, engrafted beta-cells did not show evidence of replication, and preapoptotic beta-cells, with intra- and extracellular amyloid deposition, were detected with electron microscopy. Cell cycle inhibitors p16(INK4), p21(WAF1), and p27(Kip1) were abundantly expressed in the islet grafts and showed a predominant nuclear localization. In conclusion, diabetic nude mice transplanted with human islets showed disproportionate hyperproinsulinemia and graft evidence of beta-cell restricted PC2 depletion, amyloid deposition and beta-cell death, and lack of beta-cell replication with nuclear translocation of p27(Kip1) and p21(WAF1) that together may contribute to delayed graft failure.
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Affiliation(s)
- Alberto M Davalli
- Department of Medicine, Unit of Endocrinology and Metabolic Diseases, San Raffaele Hospital, Milan, Italy.
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Yonemoto IT, Kroon GJA, Dyson HJ, Balch WE, Kelly JW. Amylin proprotein processing generates progressively more amyloidogenic peptides that initially sample the helical state. Biochemistry 2008; 47:9900-10. [PMID: 18710262 DOI: 10.1021/bi800828u] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Human amylin, or islet amyloid polypeptide, is a peptide cosecreted with insulin by the beta cells of the pancreatic islets of Langerhans. The 37-residue, C-terminally amidated human amylin peptide derives from a proprotein that undergoes disulfide bond formation in the endoplasmic reticulum and is then subjected to four enzymatic processing events in the immature secretory granule. Human amylin forms both intracellular and extracellular amyloid deposits in the pancreas of most type II diabetic subjects, likely reflecting compromised secretory cell function. In addition, amylin processing intermediates, postulated to initiate intracellular amyloidogenesis, have been reported as components of intracellular amyloid in beta cells. We investigated the amyloidogenicity of amylin and its processing intermediates in vitro. Chaotrope-denatured amylin and amylin processing intermediates were subjected to size exclusion chromatography, affording high concentrations of monomeric peptides. NMR studies reveal that human amylin samples helical conformations. Under conditions mimicking the immature secretory granule (37 degrees C, pH 6), amylin forms amyloid aggregates more rapidly than its processing intermediates, and more rapidly than its reduced counterparts. Our studies also show that the amyloidogenicity of amylin and its processing intermediates is negatively correlated with net charge and charge at the C-terminus. Although our conditions may not precisely reflect those of amyloidogenesis in vivo, the lower amyloidogenicity of the processing intermediates relative to amylin suggests their presence in intracellular amyloid deposits in the increasingly stressed beta cells of diabetic subjects may be a consequence of general defects in protein homeostasis control known to occur in diabetes rather than serving as amyloid initiators.
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Affiliation(s)
- Isaac T Yonemoto
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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20
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Real-time monitoring of apoptosis by caspase-3-like protease induced FRET reduction triggered by amyloid aggregation. EXPERIMENTAL DIABETES RESEARCH 2008; 2008:865850. [PMID: 18566681 PMCID: PMC2426809 DOI: 10.1155/2008/865850] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 04/23/2008] [Indexed: 01/09/2023]
Abstract
Amyloid formation is cytotoxic and can activate the caspase cascade. Here, we monitor caspase-3-like activity as reduction of fluorescence resonance energy transfer (FRET) using the contstruct pFRET2-DEVD containing enhanced cyan fluorescent protin (EYFP) linked by the caspase-3 specific cleavage site residues DEVD. Beta-TC-6 cells were transfected, and the fluoorescence was measured at 440 nm excitation and 535 nm (EYFP) and 480 nm (ECFP) emission wavelength. Cells were incubated with recombinant pro lset Amyloid Polypeptide (rec prolAPP) or the processing metabolites of prolAPP; the N-terminal flanking peptide withIAPP (recN+IAPP); IAPP with the C-terminal flanking peptied (recIAPP+C) and lslet Amyloid Polypeptide (recIAPP) . Peptides were added in solubilized from (50 microM) or as performed amyloid-like fibrils, or as a combination of these. FRET was measured and incubation with a mixture of solubilized peptide and performed fibrils resulted in loss of FRET and apoptosis was determined to occure in cells incubated with recproIAPP (49%), recN+IAPP (46%), recIAPP (72%) and recIAPP+C (59%). These results show that proIAPP and the processing intermediates reside the same cell toxic capacity as IAPP, and they can all have a central role in the reduction of beta-cell number in type 2 diabetes.
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21
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Paulsson JF, Andersson A, Westermark P, Westermark GT. Intracellular amyloid-like deposits contain unprocessed pro-islet amyloid polypeptide (proIAPP) in beta cells of transgenic mice overexpressing the gene for human IAPP and transplanted human islets. Diabetologia 2006; 49:1237-46. [PMID: 16570161 DOI: 10.1007/s00125-006-0206-7] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2005] [Accepted: 12/23/2005] [Indexed: 10/24/2022]
Abstract
AIMS/HYPOTHESIS Islet amyloid is a frequent finding in the islets of Langerhans of individuals with type 2 diabetes. The main amyloid constituent is the beta cell-derived polypeptide hormone islet amyloid polypeptide (IAPP). In general, amyloid refers to an extracellular deposit of a congophilic material, but intracellular amyloid is seen in some beta cells of transgenic mice expressing the gene for human IAPP and in human islets transplanted into nude mice. The aim of this study was to immunohistochemically characterise the intracellular amyloid. METHODS Antisera against the N- and C-terminal processing sites of proIAPP (which were therefore specific for proIAPP), the C-terminal flanking peptide and mature IAPP were used for immunoelectron microscopy. RESULTS Fibrillar aggregates were seen in the halo region of the secretory granules in some beta cells in human IAPP transgenic mice. These aggregates were labelled with proIAPP-specific antisera. Also, proIAPP reactivity was more widespread in the intracellular amyloid-like aggregates in beta cells of transgenic mice than in human islet transplants, in which the intracellular amyloid-like deposits were larger, but the proIAPP labelling was restricted to small spots within the amyloid deposits. CONCLUSIONS/INTERPRETATION We suggest that proIAPP forms the first amyloid fibrils and that this can occur already in the secretory granules of the beta cells. The proIAPP-derived fibrils can act as seed for further amyloid formation, now made up by IAPP. The observed difference between human islet transplants and human IAPP transgenic animals may reflect differences in stages of amyloid development.
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Affiliation(s)
- J F Paulsson
- Division of Cell Biology, Diabetes Research Centre, Linköping University, Linköping, Sweden
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22
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Bronský J, Průsa R, Nevoral J. The role of amylin and related peptides in osteoporosis. Clin Chim Acta 2006; 373:9-16. [PMID: 16797521 DOI: 10.1016/j.cca.2006.05.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2006] [Revised: 05/02/2006] [Accepted: 05/05/2006] [Indexed: 12/18/2022]
Abstract
Osteoporosis is a systemic skeletal disorder that remains a major public health problem due to significant fracture-associated morbidity and mortality. Because it has been shown that individuals having type I diabetes mellitus also suffer from osteopenia or osteoporosis, there is probably a pathophysiological mechanism that links pancreatic beta cell insufficiency with inappropriate bone formation. Many factors have been suggested, including amylin, a product of pancreatic beta cells with structural and functional similarity to calcitonin. Amylin has been shown to stimulate bone development via action on osteoblasts and osteoclasts. Recently, amylin receptors have been identified as complexed calcitonin receptor with receptor activity modifying proteins. Moreover, a synthetic amylin analogue (pramlintide) has been developed for clinical use. These findings including results from in vitro animal and human studies suggest a role for amylin as a potential diagnostic and therapeutical tool in patients with various bone diseases including osteoporosis. However, other structurally and functionally related hormones that affect bone metabolism should also be taken in account including calcitonin, calcitonin gene-related peptide and adrenomedullin.
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Affiliation(s)
- Jirí Bronský
- Department of Clinical Biochemistry and Pathobiochemistry, 2nd Medical Faculty, Charles University and Faculty Hospital Motol, V Uvalu 84, 150 06 Prague 5, Czech Republic.
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Jeha GS, Heptulla RA. Newer therapeutic options for children with diabetes mellitus: theoretical and practical considerations. Pediatr Diabetes 2006; 7:122-38. [PMID: 16629719 DOI: 10.1111/j.1399-543x.2006.00159.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Recent studies in adult patients with type 1 diabetes mellitus (T1DM) and T2DM have examined the potential utility, benefits, and side effects of agents that augment insulin secretion after oral ingestion of nutrients in comparison with intravenous nutrient delivery, the so-called incretins. Two families of incretin-like substances are now approved for use in adults. Glucagon-like peptide-1 (GLP-1) or agents that bind to its receptor (exenatide, Byetta) or agents that inhibit its destruction [dipeptidyl peptidase-IV (DPP-IV) inhibitors, Vildagliptin] improve insulin secretion, delay gastric emptying, and suppress glucagon secretion while decreasing food intake without increasing hypoglycemia. Pramlintide, a synthetic amylin analog, also decreases glucagon secretion and delays gastric emptying, improves hemoglobin A1c (HbA1C), and facilitates weight reduction without causing hypoglycemia. We review the historical discovery of these agents, their physiology [corrected] and their current applications. Remarkably, only one or two studies have been reported in children. Pediatricians caring for children with T1DM and T2DM should become familiar with these agents and investigate their applicability, as they seem likely to enhance our therapeutic armamentarium to treat children with diabetes mellitus.
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Affiliation(s)
- George S Jeha
- Department of Pediatrics, Division of Pediatric Endocrinology [corrected] and Metabolism, Texas Children's Hospital, Baylor College of Medicine, Houston, TX 77030, USA
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25
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Höppener JWM, Lips CJM. Role of islet amyloid in type 2 diabetes mellitus. Int J Biochem Cell Biol 2006; 38:726-36. [PMID: 16459127 DOI: 10.1016/j.biocel.2005.12.009] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2005] [Revised: 12/05/2005] [Accepted: 12/12/2005] [Indexed: 01/09/2023]
Abstract
Diabetes mellitus is one of the most common metabolic diseases worldwide and its prevalence is rapidly increasing. Due to its chronic nature (diabetes mellitus can be treated but as yet not cured) and its serious complications, it is one of the most expensive diseases with regard to total health care costs per patient. The elevated blood glucose levels in diabetes mellitus are caused by a defect in production and/or secretion of the polypeptide hormone insulin, which normally promotes glucose-uptake in cells. Insulin is produced by the pancreatic 'beta-cells' in the 'islets of Langerhans', which lie distributed within the exocrine pancreatic tissue. In type 2 diabetes mellitus, the initial defect in the pathogenesis of the disease in most of the patients is believed to be 'insulin resistance'. Hyperglycemia (clinically overt diabetes mellitus) will not develop as long as the body is able to produce enough insulin to compensate for the reduced insulin action. When this compensation fails ('beta-cell failure') blood glucose levels will become too high. In this review, we discuss one of the mechanisms that have been implicated in the development of beta-cell failure, i.e. amyloid formation in the pancreatic islets. This islet amyloid is a characteristic histopathological feature of type 2 diabetes mellitus and both in vitro and in vivo studies have revealed that its formation causes death of islet beta-cells. Being a common pathogenic factor in an otherwise heterogeneous disease, islet amyloidosis is an attractive novel target for therapeutic intervention in type 2 diabetes mellitus.
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Affiliation(s)
- Jo W M Höppener
- Department of Metabolic and Endocrine Diseases, University Medical Center Utrecht, The Netherlands.
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26
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Paulsson JF, Westermark GT. Aberrant processing of human proislet amyloid polypeptide results in increased amyloid formation. Diabetes 2005; 54:2117-25. [PMID: 15983213 DOI: 10.2337/diabetes.54.7.2117] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The amyloid present in the islets of Langerhans in type 2 diabetes is polymerized islet amyloid polypeptide (IAPP). The precursor protein proIAPP is posttranslationally modified, a process involving the removal of NH2- and COOH-terminal flanking peptides. This step is performed by the prohormone convertases PC2 and PC1/3. PC2 processes proIAPP preferably at the NH2-terminal processing site, and PC1/3 processes proIAPP exclusively at the COOH-terminal site. Little is known regarding the exact circumstances leading to islet amyloid formation. In this study, we have examined the possible significance of aberrant processing of proIAPP on amyloid formation in several in vitro cellular systems. In our studies, human (h)-proIAPP was transfected into beta-TC-6 cells expressing both prohormone convertases and in which proIAPP is processed into IAPP. Additionally, h-proIAPP was transfected into three different pituitary-derived cell lines with different prohormone convertase profiles: AtT-20 cells (deficient in PC2), GH3 cells (deficient in PC1/3), and GH4C1 cells (deficient in both convertases). We followed the processing of h-proIAPP with antibodies specific for the respective cleavage sites and stained the cells with Congo red to verify the accumulation of amyloid. Incomplete processing of h-proIAPP that occurs in AtT-20 and GH4C1 cells resulted in the formation of intracellular amyloid. No amyloid developed in beta-TC-6 and GH3 cells lines with full processing of proIAPP. An intracellular increase in proIAPP and/or its metabolic products may thus promote intracellular amyloid formation, thereby causing cell death. When extracellularly exposed, this amyloid might act as template for continuing amyloid formation from processed IAPP released from the surrounding beta-cells.
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Affiliation(s)
- Johan F Paulsson
- Deparment of Biomedicine and Surgery, Division of Cell Biology, Linköping University, SE 581 85 Linköping, Sweden
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Lopes DHJ, Colin C, Degaki TL, de Sousa ACV, Vieira MNN, Sebollela A, Martinez AMB, Bloch C, Ferreira ST, Sogayar MC. Amyloidogenicity and cytotoxicity of recombinant mature human islet amyloid polypeptide (rhIAPP). J Biol Chem 2004; 279:42803-10. [PMID: 15292167 DOI: 10.1074/jbc.m406108200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pancreatic amyloid plaques formed by the pancreatic islet amyloid polypeptide (IAPP) are present in more than 95% of type II diabetes mellitus patients, and their abundance correlates with the severity of the disease. IAPP is currently considered the most amyloidogenic peptide known, but the molecular bases of its aggregation are still incompletely understood. Detailed characterization of the mechanisms of amyloid formation requires large quantities of pure material. Thus, availability of recombinant IAPP in sufficient amounts for such studies constitutes an important step toward elucidation of the mechanisms of amyloidogenicity. Here, we report, for the first time, the successful expression, purification and characterization of the amyloidogenicity and cytotoxicity of recombinant human mature IAPP. This approach is likely to be useful for the production of other amyloidogenic peptides or proteins that are difficult to obtain by chemical synthesis.
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MESH Headings
- Amino Acid Sequence
- Amyloid/chemistry
- Amyloid/metabolism
- Base Sequence
- Cells, Cultured
- Cloning, Molecular
- DNA, Complementary/metabolism
- Dose-Response Relationship, Drug
- Electrophoresis, Polyacrylamide Gel
- Escherichia coli/metabolism
- Glycine/analogs & derivatives
- Glycine/chemistry
- Humans
- Islet Amyloid Polypeptide
- Microscopy, Electron
- Microscopy, Fluorescence
- Molecular Sequence Data
- Mutation
- Peptides/chemistry
- Protein Structure, Tertiary
- Recombinant Fusion Proteins/chemistry
- Recombinant Proteins/chemistry
- Reverse Transcriptase Polymerase Chain Reaction
- Spectrometry, Fluorescence
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Time Factors
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Affiliation(s)
- Dahabada H J Lopes
- Departamento de Bioquímica Médica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brazil
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28
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Bronský J, Průsa R. Amylin fasting plasma levels are decreased in patients with osteoporosis. Osteoporos Int 2004; 15:243-7. [PMID: 14605801 DOI: 10.1007/s00198-003-1538-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2002] [Accepted: 10/02/2003] [Indexed: 12/18/2022]
Abstract
Amylin is a polypeptide hormone produced in pancreatic beta-cells that belongs to the family of calcitonin gene-related peptides. There is a 20% sequence homology between amylin and calcitonin and 44% homology with calcitonin gene-related peptide. Amylin and its fragments stimulate the proliferation of osteoblasts, inhibit bone resorption, and increase bone density and the amount of bone mass. We measured amylin total and unreduced amylin fasting plasma levels in patients with osteoporosis ( n=28; 3 men, 25 women; mean age 65 years), type 2 diabetes mellitus ( n=10; 5 men, 5 women; 64 years), and in the control group ( n=24; 11 men, 13 women; 53 years) using an ELISA kit with immunofluorescent detection (Linco). Amylin total plasma levels in patients with osteoporosis were 3.33+/-0.46 pmol/l (mean+/-SEM), in patients with type 2 diabetes 6.29+/-1.47 pmol/l (mean+/-SEM), and in the control group 8.48+/-3.12 pmol/l (mean+/-SEM). Mean plasma levels were lower in patients with osteoporosis than in patients with type 2 diabetes and in the control group. Unreduced amylin plasma levels in patients with osteoporosis ( n=28) were 2.51+/-0.87 pmol/l (mean+/-SEM), in patients with type 2 diabetes ( n=10) 4.15+/-0.95 pmol/l (mean+/-SEM) and in the control group ( n=5) 13.50+/-3.94 pmol/l (mean+/-SEM). Plasma levels were significantly lower in patients with osteoporosis than in patients with type 2 diabetes ( P<0.01) and in the control group ( P<0.001). Amylin plasma levels are decreased in patients with osteoporosis. Amylin deficiency in these patients may contribute to the development of osteoporosis. Amylin should be investigated in relation to the pharmacological treatment of osteoporosis.
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Affiliation(s)
- J Bronský
- Department of Clinical Biochemistry and Pathobiochemistry, 2nd Medical Faculty, Charles University and Faculty Hospital Motol, V Uvalu 84, 150 06, Prague, Czech Republic.
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29
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Andrikopoulos S, Hull RL, Verchere CB, Wang F, Wilbur SM, Wight TN, Marzban L, Kahn SE. Extended life span is associated with insulin resistance in a transgenic mouse model of insulinoma secreting human islet amyloid polypeptide. Am J Physiol Endocrinol Metab 2004; 286:E418-24. [PMID: 14613923 DOI: 10.1152/ajpendo.00137.2003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pancreatic amyloid is found in patients with insulinomas and type 2 diabetes. To study mechanisms of islet amyloidogenesis, we produced transgenic mice expressing the unique component of human islet amyloid, human islet amyloid polypeptide (hIAPP). These mice develop islet amyloid after 12 mo of high-fat feeding. To determine whether we could accelerate the rate of islet amyloid formation, we crossbred our hIAPP transgenic animals with RIP-Tag mice that develop islet tumors and die at 12 wk of age from hypoglycemia. At 12 wk of age, this new line of hIAPPxRIP-Tag mice was heavier (29.7 +/- 1.0 vs. 25.0 +/- 1.3 g, P < 0.05) and had increased plasma glucose levels (4.6 +/- 0.4 vs. 2.9 +/- 0.6 mmol/l, P < 0.05) compared with littermate RIP-Tag mice. However, the hIAPPxRIP-Tag mice did not display islet amyloid or amyloid fibrils despite high circulating hIAPP levels (24.6 +/- 7.0 pmol/l). Interestingly, hIAPPxRIP-Tag mice had a longer life span than RIP-Tag mice (121 +/- 8 vs. 102 +/- 5 days, P < 0.05). This increase in life span in hIAPPxRIP-Tag was positively correlated with body weight (r = 0.48, P < 0.05) and was associated with decreased insulin sensitivity compared with RIP-Tag mice. hIAPPxRIP-Tag mice did not develop amyloid during their 4-mo life span, suggesting that increased hIAPP secretion is insufficient for islet amyloid formation within such a short time. However, hIAPPxRIP-Tag mice did have an increase in life span that was associated with insulin resistance, suggesting that hIAPP has extrapancreatic effects, possibly on peripheral glucose metabolism.
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Affiliation(s)
- Sofianos Andrikopoulos
- Department of Medicine, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, Washington, USA
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30
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Clark A, Nilsson MR. Islet amyloid: a complication of islet dysfunction or an aetiological factor in Type 2 diabetes? Diabetologia 2004; 47:157-69. [PMID: 14722650 DOI: 10.1007/s00125-003-1304-4] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2003] [Revised: 11/04/2003] [Indexed: 12/30/2022]
Abstract
The role of islet amyloidosis in the onset and progression of Type 2 diabetes remains obscure. Islet amyloid polypeptide is a 37 amino-acid, beta-cell peptide which is co-stored and co-released with insulin. Human islet amyloid polypeptide refolds to a beta-conformation and oligomerises to form insoluble fibrils; proline substitutions in rodent islet amyloid polypeptide prevent this molecular transition. Pro-islet amyloid polypeptide (67 amino acids in man) is processed in secretory granules. Refolding of islet amyloid polypeptide may be prevented by intragranular heterodimer formation with insulin (but not proinsulin). Diabetes-associated abnormal proinsulin processing could contribute to de-stabilisation of granular islet amyloid polypeptide. Increased pro-islet amyloid polypeptide secretion as a consequence of islet dysfunction could promote fibrillogenesis; the propeptide forms fibrils and binds to basement membrane glycosamino-glycans. Islet amyloid polypeptide gene polymorphisms are not universally associated with Type 2 diabetes. Transgenic mice expressing human islet amyloid polypeptide gene have increased islet amyloid polypeptide concentrations but develop islet amyloid only against a background of obesity and/or high fat diet. In transgenic mice, obese monkeys and cats, initially small perivascular deposits progressively increase to occupy 80% islet mass; the severity of amyloidosis in animal models is related to the onset of hyperglycaemia, suggesting that islet amyloid and the associated destruction of islet cells cause diabetes. In human diabetes, islet amyloid can affect less than 1% or up to 80% of islets indicating that islet amyloidosis largely results from diabetes-related pathologies and is not an aetiological factor for hyperglycaemia. However, the associated progressive beta-cell destruction leads to severe islet dysfunction and insulin requirement.
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Affiliation(s)
- A Clark
- Diabetes Research Laboratories, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, UK.
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31
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Kayton ML, Costouros NG, Lorang D, Alexander HR, Hewitt SM, Cochran C, Shalev A, Harlan D, Skarulis MC, Gorden P, Libutti SK. Peak stimulated insulin secretion is associated with specific changes in gene expression profiles in sporadic insulinomas. Surgery 2004; 134:982-7; discussion 987-8. [PMID: 14668731 DOI: 10.1016/j.surg.2003.07.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND The molecular pathways that are responsible for pathologic insulin secretion by insulinomas have not been characterized. We studied gene expression profiles from insulinomas and determined associations between these changes and preoperative peak serum insulin levels. METHODS Ten patients with insulinomas underwent calcium-stimulated arteriography and surgical resection. Tumor RNA was isolated; corresponding complementary DNA was hybridized to 10K human complementary DNA arrays. Pooled human islet cell complementary DNA served as the control. Cluster analysis of gene expression and analysis of expression ratios was performed. RESULTS Nineteen genes were up-regulated at least 3-fold in insulinomas compared with controls, which included the genes for islet amyloid polypeptide and proprotein convertase type 2. Cluster analysis revealed 2 groups of patients with insulinoma and with distinct patterns of gene expression. Mean peak serum insulin values between groups were 196 and 1100 (U/mL (P<.05), which demonstrates a significant difference in insulin response to calcium stimulation between these 2 groups. CONCLUSION We show that genes that are relevant to the pathogenesis of hyperinsulinemia are expressed preferentially in insulinomas. In addition, patients with a distinct and common pattern of gene expression had significantly higher stimulated insulin secretion levels. The study of these genes may help to identify the biochemical pathways that are responsible for pathologic insulin secretion.
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Affiliation(s)
- Mark L Kayton
- Surgery Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Building 10, 10 Center Drive, Bethesda, MD 20892, USA
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32
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Marzban L, Trigo-Gonzalez G, Zhu X, Rhodes CJ, Halban PA, Steiner DF, Verchere CB. Role of beta-cell prohormone convertase (PC)1/3 in processing of pro-islet amyloid polypeptide. Diabetes 2004; 53:141-8. [PMID: 14693708 DOI: 10.2337/diabetes.53.1.141] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Islet amyloid polypeptide (IAPP) (amylin), the major component of islet amyloid, is produced by cleavage at the COOH- and NH(2)-termini of its precursor, proIAPP, likely by the beta-cell prohormone convertases (PC) 1/3 and PC2. Mice lacking PC2 can process proIAPP at its COOH- but not its NH(2)-terminal cleavage site, suggesting that PC1/3 is capable of initiating proIAPP cleavage at its COOH-terminus. To determine the precise role of PC1/3 in proIAPP processing, Western blot analysis was performed on islets isolated from mice lacking PC1/3 (PC1/3(-/-)). These islets contained not only fully processed IAPP as in PC1/3(+/+) islets, but also elevated levels of a COOH-terminally unprocessed intermediate form, suggesting impaired processing at the COOH-terminus. Next, GH3 cells that do not normally express proIAPP or detectable levels of PC1/3 or PC2 were cotransduced with adenoviruses expressing rat proIAPP and either PC2 or PC1/3. As expected, in GH3 cells transduced to express only proIAPP, no processing was observed. Coexpression of proIAPP and PC2 resulted in production of mature IAPP, whereas in cells that coexpressed proIAPP and PC1/3 only a 6-kDa intermediate was produced. We conclude that PC1/3 is important for processing of proIAPP at the COOH-terminus, but in its absence, PC2 can initiate complete processing of proIAPP to IAPP by cleaving the precursor at either its NH(2)- or COOH-terminal cleavage sites.
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Affiliation(s)
- Lucy Marzban
- Department of Pathology and Laboratory Medicine & British Columbia Research Institute for Children's and Women's Health, University of British Columbia, Vancouver, British Columbia, Canada
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33
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Scrocchi LA, Chen Y, Wang F, Han K, Ha K, Wu L, Fraser PE. Inhibitors of islet amyloid polypeptide fibrillogenesis, and the treatment of type-2 diabetes. Int J Pept Res Ther 2003. [DOI: 10.1007/s10989-004-2423-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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34
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Scrocchi LA, Chen Y, Wang F, Han K, Ha K, Wu L, Fraser PE. Inhibitors of islet amyloid polypeptide fibrillogenesis, and the treatment of type-2 diabetes. ACTA ACUST UNITED AC 2003. [DOI: 10.1007/bf02442587] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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35
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Hull RL, Andrikopoulos S, Verchere CB, Vidal J, Wang F, Cnop M, Prigeon RL, Kahn SE. Increased dietary fat promotes islet amyloid formation and beta-cell secretory dysfunction in a transgenic mouse model of islet amyloid. Diabetes 2003; 52:372-9. [PMID: 12540610 DOI: 10.2337/diabetes.52.2.372] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Transgenic mice expressing the amyloidogenic human islet amyloid polypeptide (hIAPP) in their islet beta-cells are a model of islet amyloid formation as it occurs in type 2 diabetes. Our hIAPP transgenic mice developed islet amyloid when fed a breeder chow but not regular chow. Because the breeder chow contained increased amounts of fat, we hypothesized that increased dietary fat enhances islet amyloid formation. To test this hypothesis, we fed male hIAPP transgenic and nontransgenic control mice diets containing 15% (low fat), 30% (medium fat), or 45% (high fat) of calories derived from fat for 12 months, and we measured islet amyloid, islet endocrine cell composition, and beta-cell function. Increased dietary fat in hIAPP transgenic mice was associated with a dose-dependent increase in both the prevalence (percentage of islets containing amyloid deposits; 34 +/- 8, 45 +/- 8, and 58 +/- 10%, P < 0.05) and severity (percentage of islet area occupied by amyloid; 0.8 +/- 0.5, 1.0 +/- 0.5, and 4.6 +/- 2.5%, P = 0.05) of islet amyloid. In addition, in these hIAPP transgenic mice, there was a dose-dependent decrease in the proportion of islet area comprising beta-cells, with no significant change in islet size. In contrast, nontransgenic mice adapted to diet-induced obesity by increasing their islet size more than twofold. Increased dietary fat was associated with impaired insulin secretion in hIAPP transgenic (P = 0.05) but not nontransgenic mice. In summary, dietary fat enhances both the prevalence and severity of islet amyloid and leads to beta-cell loss and impaired insulin secretion. Because both morphologic and functional defects are present in hIAPP transgenic mice, this would suggest that the effect of dietary fat to enhance islet amyloid formation might play a role in the pathogenesis of the islet lesion of type 2 diabetes in humans.
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Affiliation(s)
- Rebecca L Hull
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle 98108, USA.
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36
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Scrocchi LA, Chen Y, Waschuk S, Wang F, Cheung S, Darabie AA, McLaurin J, Fraser PE. Design of peptide-based inhibitors of human islet amyloid polypeptide fibrillogenesis. J Mol Biol 2002; 318:697-706. [PMID: 12054816 DOI: 10.1016/s0022-2836(02)00164-x] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human islet amyloid polypeptide (IAPP) is the major component of amyloid deposits found in the pancreas of over 90% of all cases of type-2 diabetes. We have generated a series of overlapping hexapeptides to target an amyloidogenic region of IAPP (residues 20-29) and examined their effects on fibril assembly. Peptide fragments corresponding to SNNFGA (residues 20-25) and GAILSST (residues 24-29) were strong inhibitors of the beta-sheet transition and amyloid aggregation. Circular dichroism indicated that even at 1:1 molar ratios, these peptides maintained full-length IAPP (1-37) in a largely random coil conformation. Negative stain electron microscopy revealed that co-incubation of these peptides with IAPP resulted in the formation of only semi-fibrous aggregates and loss of the typical high density and morphology of IAPP fibrils. This inhibitory activity, particularly for the SNNFGA sequence, also correlated with a reduction in IAPP-induced cytotoxicity as determined by cell culture studies. In contrast, the peptide NFGAIL (residues 22-27) enhanced IAPP fibril formation. Conversion to the amyloidogenic beta-sheet was immediate and the accompanying fibrils were more dense and complex than IAPP alone. The remaining peptide fragments either had no detectable effects or were only weakly inhibitory. Specificity of peptide activity was illustrated by the fragments, SSNNFG and AILSST. These differed from the most active inhibitors by only a single amino acid residue but delayed the random-to-beta conformational change only when used at higher molar ratios. This study has identified internal IAPP peptide fragments which can regulate fibrillogenesis and may be of therapeutic use for the treatment of type-2 diabetes.
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Affiliation(s)
- Louise A Scrocchi
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Tanz Neuroscience Building, 6 Queen's Park Crescent West, Toronto, Ontario, Canada M5S 3H2.
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37
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Jaikaran ET, Clark A. Islet amyloid and type 2 diabetes: from molecular misfolding to islet pathophysiology. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1537:179-203. [PMID: 11731221 DOI: 10.1016/s0925-4439(01)00078-3] [Citation(s) in RCA: 223] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Islet amyloid polypeptide (IAPP, amylin) is secreted from pancreatic islet beta-cells and converted to amyloid deposits in type 2 diabetes. Conversion from soluble monomer, IAPP 1-37, to beta-sheet fibrils involves changes in the molecular conformation, cellular biochemistry and diabetes-related factors. In addition to the recognised amyloidogenic region, human IAPP (hIAPP) 20-29, the peptides human or rat IAPP 30-37 and 8-20, assume beta-conformation and form fibrils. These three amyloidogenic regions of hIAPP can be modelled as a folding intermediate with an intramolecular beta-sheet. A hypothesis is proposed for co-secretion of proIAPP with proinsulin in diabetes and formation of a 'nidus' adjacent to islet capillaries for subsequent accumulation of secreted IAPP to form the deposit. Although intracellular fibrils have been identified in experimental systems, extracellular deposition predominates in animal models and man. Extensive fibril accumulations replace islet cells. The molecular species of IAPP that is cytotoxic remains controversial. However, since fibrils form invaginations in cell membranes, small non-toxic IAPP fibrillar or amorphous accumulations could affect beta-cell stimulus-secretion coupling. The level of production of hIAPP is important but not a primary factor in islet amyloidosis; there is little evidence for inappropriate IAPP hypersecretion in type 2 diabetes and amyloid formation is generated in transgenic mice overexpressing the gene for human IAPP only against a background of obesity. Animal models of islet amyloidosis suggest that diabetes is induced by the deposits whereas in man, fibril formation appears to result from diabetes-associated islet dysfunction. Islet secretory failure results from progressive amyloidosis which provides a target for new therapeutic interventions.
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Affiliation(s)
- E T Jaikaran
- Diabetes Research Laboratories, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Infirmary, Woodstock Road, Oxford, UK
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38
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Park K, Verchere CB. Identification of a heparin binding domain in the N-terminal cleavage site of pro-islet amyloid polypeptide. Implications for islet amyloid formation. J Biol Chem 2001; 276:16611-6. [PMID: 11145957 DOI: 10.1074/jbc.m008423200] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Islet amyloid deposits are a characteristic pathologic lesion of the pancreas in type 2 diabetes and are composed primarily of the islet beta cell peptide islet amyloid polypeptide (IAPP or amylin) as well as the basement membrane heparan sulfate proteoglycan perlecan. Impaired processing of the IAPP precursor has been implicated in the mechanism of islet amyloid formation. The N- and C-terminal cleavage sites where pro-IAPP is processed by prohormone convertases contain a series of basic amino acid residues that we hypothesized may interact with heparan sulfate proteoglycans. This possibility was tested using affinity chromatography by applying synthetic fragments of pro-IAPP to heparin-agarose and heparan sulfate-Sepharose. An N-terminal human pro-IAPP fragment (residues 1-30) was retained by both heparin-agarose and heparan sulfate-Sepharose, eluting at 0.18 m NaCl at pH 7.5. Substitution of alanine residues for two basic residues in the N-terminal cleavage site abolished heparin and heparan sulfate binding activity. At pH 5.5, the affinity of the wild-type peptide for heparin/heparan sulfate was increased, implying a role for histidine residues at positions 6 and 28 of pro-IAPP. A C-terminal pro-IAPP fragment (residues 41-67) had no specific affinity for either heparin or heparan sulfate, and the N- or C-terminal fragments had only weak affinity for chondroitin sulfate. These data suggest that monomeric N-terminal human pro-IAPP contains a heparin binding domain that is lost during normal processing of pro-IAPP.
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Affiliation(s)
- K Park
- Department of Pathology and Laboratory Medicine and the British Columbia Research Institute for Children's and Women's Health, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
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39
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Park K, Verchere CB. Identification of a Heparin Binding Domain in the N-terminal Cleavage Site of Pro-islet Amyloid Polypeptide. J Biol Chem 2001. [DOI: 10.1074/jbc.m008423200%20m008423200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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40
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Wang J, Xu J, Finnerty J, Furuta M, Steiner DF, Verchere CB. The prohormone convertase enzyme 2 (PC2) is essential for processing pro-islet amyloid polypeptide at the NH2-terminal cleavage site. Diabetes 2001; 50:534-9. [PMID: 11246872 DOI: 10.2337/diabetes.50.3.534] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Impaired processing of pro-islet amyloid polypeptide (proIAPP), the precursor of the beta-cell peptide islet amyloid polypeptide (IAPP) (amylin), has been implicated in islet amyloid formation in type 2 diabetes. The prohormone convertase enzymes PC3 (also known as PC1) and PC2 are localized to beta-cell secretory granules with proIAPP and proinsulin and are responsible for proinsulin processing. To determine whether PC2 might be essential for proIAPP processing, we performed Western blot analysis of freshly isolated islets from normal mice and mice lacking active PC2. As expected, the primary species of IAPP immunoreactivity in islets from wild-type mice was fully processed (4-kDa) IAPP, with only small amounts of the 8-kDa precursor (unprocessed proIAPP) present. Islets from heterozygous PC2 null mice were identical to wild-type animals, suggesting that half the normal complement of PC2 is sufficient for normal proIAPP processing. By contrast, in islets from homozygous PC2 null mice, the predominant IAPP-immunoreactive form was of intermediate size (approximately 6 kDa), with no detectable mature IAPP and slightly elevated amounts of the 8-kDa precursor form present. Thus, in the absence of PC2, proIAPP processing appears to be blocked at the level of a proIAPP conversion intermediate. Immunofluorescence of pancreas sections and immunoblotting using antisera raised to the NH2- and COOH-terminal flanking regions of mouse proIAPP demonstrated that the 6-kDa intermediate form was an NH2-terminally extended proIAPP conversion intermediate (processed only at the COOH-terminus). These data indicate that PC2 is essential for processing of proIAPP at the NH2-terminal cleavage site in vivo and that PC3 is likely only capable of processing proIAPP at the COOH-terminal cleavage site.
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Affiliation(s)
- J Wang
- Department of Pathology and Laboratory Medicine and the British Columbia Research Institute for Children's and Women's Health, University of British Columbia, Vancouver, Canada
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