1
|
McCalpin SD, Khemtemourian L, Suladze S, Ivanova MI, Reif B, Ramamoorthy A. Zinc and pH modulate the ability of insulin to inhibit aggregation of islet amyloid polypeptide. Commun Biol 2024; 7:776. [PMID: 38937578 PMCID: PMC11211420 DOI: 10.1038/s42003-024-06388-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 05/27/2024] [Indexed: 06/29/2024] Open
Abstract
Aggregation of the human islet amyloid polypeptide (hIAPP) contributes to the development and progression of Type 2 Diabetes (T2D). hIAPP aggregates within a few hours at few micromolar concentration in vitro but exists at millimolar concentrations in vivo. Natively occurring inhibitors of hIAPP aggregation might therefore provide a model for drug design against amyloid formation associated with T2D. Here, we describe the combined ability of low pH, zinc, and insulin to inhibit hIAPP fibrillation. Insulin dose-dependently slows hIAPP aggregation near neutral pH but had less effect on the aggregation kinetics at acidic pH. We determine that insulin alters hIAPP aggregation in two manners. First, insulin diverts the aggregation pathway to large nonfibrillar aggregates with ThT-positive molecular structure, rather than to amyloid fibrils. Second, soluble insulin suppresses hIAPP dimer formation, which is an important early aggregation event. Further, we observe that zinc significantly modulates the inhibition of hIAPP aggregation by insulin. We hypothesize that this effect arose from controlling the oligomeric state of insulin and show that hIAPP interacts more strongly with monomeric than oligomeric insulin.
Collapse
Affiliation(s)
- Samuel D McCalpin
- Biophysics Program, University of Michigan, Arbor, MI, 48109, USA
- Department of Chemistry, University of Michigan, Arbor, MI, 48109, USA
| | - Lucie Khemtemourian
- Institute of Chemistry and Biology of Membranes and Nanoobjects (CBMN), CNRS - UMR 5248, Institut Polytechnique Bordeaux, University of Bordeaux, 33600, Pessac, France
| | - Saba Suladze
- Bayerisches NMR Zentrum (BNMRZ) at the Department of Biosciences, School of Natural Sciences, Technische Universität München, Munich, Germany
- Helmholtz-Zentrum München (HMGU), Deutsches Forschungszentrum für Gesundheit und Umwelt, Institute of Structural Biology (STB), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Magdalena I Ivanova
- Biophysics Program, University of Michigan, Arbor, MI, 48109, USA
- Department of Neurology, University of Michigan, Arbor, MI, 48109, USA
- Michigan Neuroscience Institute, University of Michigan, Arbor, MI, 48109, USA
| | - Bernd Reif
- Bayerisches NMR Zentrum (BNMRZ) at the Department of Biosciences, School of Natural Sciences, Technische Universität München, Munich, Germany
- Helmholtz-Zentrum München (HMGU), Deutsches Forschungszentrum für Gesundheit und Umwelt, Institute of Structural Biology (STB), Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Ayyalusamy Ramamoorthy
- Biophysics Program, University of Michigan, Arbor, MI, 48109, USA.
- Department of Chemistry, University of Michigan, Arbor, MI, 48109, USA.
- Department of Neurology, University of Michigan, Arbor, MI, 48109, USA.
- Michigan Neuroscience Institute, University of Michigan, Arbor, MI, 48109, USA.
- Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
- National High Magnetic Field Laboratory, Department of Chemical and Biomedical Engineering, Institute of Molecular Biophysics, Neuroscience, Florida State University, Tallahassee, FL, 32310, USA.
| |
Collapse
|
2
|
Florio D, Luciano P, Di Natale C, Marasco D. The effects of histidine substitution of aromatic residues on the amyloidogenic properties of the fragment 264-277 of nucleophosmin 1. Bioorg Chem 2024; 147:107404. [PMID: 38678777 DOI: 10.1016/j.bioorg.2024.107404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 04/15/2024] [Accepted: 04/25/2024] [Indexed: 05/01/2024]
Abstract
Histidine (His) plays a key role in mediating protein interactions and its unique side chain determines pH responsive self-assembling processes and thus in the formation of nanostructures. In this study, To identify novel self-assembling bioinspired sequences, we analyzed a series of peptide sequences obtained through the point mutation of aromatic residues of 264-277 fragment of nucleophosmin 1 (NPM1) with single and double histidines. Through several orthogonal biophysical techniques and under different pH and ionic strength conditions we evaluated the effects of these substitutions in the amyloidogenic features of derived peptides. The results clearly indicate that both the type of aromatic mutated residue and its position can have different effect on amyloid-like behaviors. They corroborate the crucial role exerted by Tyr271 in the self-assembling process of CTD of NPM1 in AML mutated form and add novel insights in the accurate investigation of how side chain orientations can determine successful design of innovative bioinspired materials.
Collapse
Affiliation(s)
- Daniele Florio
- Department of Pharmacy, University of Naples "Federico II", 80131 Naples, Italy
| | - Paolo Luciano
- Department of Pharmacy, University of Naples "Federico II", 80131 Naples, Italy
| | - Concetta Di Natale
- Department of Ingegneria Chimica, dei Materiali e della Produzione Industriale (DICMAPI), Italy
| | - Daniela Marasco
- Department of Pharmacy, University of Naples "Federico II", 80131 Naples, Italy.
| |
Collapse
|
3
|
Roy D, Maity NC, Kumar S, Maity A, Ratha BN, Biswas R, Maiti NC, Mandal AK, Bhunia A. Modulatory role of copper on hIAPP aggregation and toxicity in presence of insulin. Int J Biol Macromol 2023; 241:124470. [PMID: 37088193 DOI: 10.1016/j.ijbiomac.2023.124470] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/24/2023] [Accepted: 04/12/2023] [Indexed: 04/25/2023]
Abstract
Aggregation of the human islets amyloid polypeptide, or hIAPP, is linked to β-cell death in type II diabetes mellitus (T2DM). Different pancreatic β-cell environmental variables such as pH, insulin and metal ions play a key role in controlling the hIAPP aggregation. Since insulin and hIAPP are co-secreted, it is known from numerous studies that insulin suppresses hIAPP fibrillation by preventing the initial dimerization process. On the other hand, zinc and copper each have an inhibitory impact on hIAPP fibrillation, but copper promotes the production of toxic oligomers. Interestingly, the insulin oligomeric equilibrium is controlled by the concentration of zinc ions when the effect of insulin and zinc has been tested together. Lower zinc concentrations cause the equilibrium to shift towards the monomer and dimer states of insulin, which bind to monomeric hIAPP and stop it from developing into a fibril. On the other hand, the combined effects of copper and insulin have not yet been done. In this study, we have demonstrated how the presence of copper affects hIAPP aggregation and the toxicity of the resultant conformers with or without insulin. For this purpose, we have used a set of biophysical techniques, including NMR, fluorescence, CD etc., in combination with AFM and cell cytotoxicity assay. In the presence and/or absence of insulin, copper induces hIAPP to form structurally distinct stable toxic oligomers, deterring the fibrillation process. More specifically, the oligomers generated in the presence of insulin have slightly higher toxicity than those formed in the absence of insulin. This research will increase our understanding of the combined modulatory effect of two β-cell environmental factors on hIAPP aggregation.
Collapse
Affiliation(s)
- Dipanwita Roy
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata 700091, India
| | - Narayan Chandra Maity
- Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Sector-III, Salt Lake, Kolkata 700106, India
| | - Sourav Kumar
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata 700091, India
| | - Anupam Maity
- Structural Biology and Bioinformatics, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Bhisma N Ratha
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata 700091, India
| | - Ranjit Biswas
- Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Sector-III, Salt Lake, Kolkata 700106, India
| | - Nakul Chandra Maiti
- Structural Biology and Bioinformatics, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Atin Kumar Mandal
- Division of Molecular Medicine, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata, 700091, India
| | - Anirban Bhunia
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata 700091, India.
| |
Collapse
|
4
|
Saxena V, Steendam R, Jansen TLC. Distinguishing islet amyloid polypeptide fibril structures with infrared isotope-label spectroscopy. J Chem Phys 2022; 156:055101. [DOI: 10.1063/5.0082322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Vishesh Saxena
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Ruben Steendam
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Thomas L. C. Jansen
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| |
Collapse
|
5
|
Pathak BK, Dey S, Mozumder S, Sengupta J. The role of membranes in function and dysfunction of intrinsically disordered amyloidogenic proteins. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 128:397-434. [PMID: 35034725 DOI: 10.1016/bs.apcsb.2021.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Membrane-protein interactions play a major role in human physiology as well as in diseases pathology. Interaction of a protein with the membrane was previously thought to be dependent on well-defined three-dimensional structure of the protein. In recent decades, however, it has become evident that a large fraction of the proteome, particularly in eukaryotes, stays disordered in solution and these proteins are termed as intrinsically disordered proteins (IDPs). Also, a vast majority of human proteomes have been reported to contain substantially long disordered regions, called intrinsically disordered regions (IDRs), in addition to the structurally ordered regions. IDPs exist in an ensemble of conformations and the conformational flexibility enables IDPs to achieve functional diversity. IDPs (and IDRs) are found to be important players in cell signaling, where biological membranes act as anchors for signaling cascades. Therefore, IDPs modulate the membrane architectures, at the same time membrane composition also affects the binding of IDPs. Because of intrinsic disorders, misfolding of IDPs often leads to formation of oligomers, protofibrils and mature fibrils through progressive self-association. Accumulation of amyloid-like aggregates of some of the IDPs is a known causative agent for numerous diseases. In this chapter we highlight recent advances in understanding membrane interactions of some of the intrinsically disordered proteins involved in the pathogenesis of human diseases.
Collapse
Affiliation(s)
- Bani Kumar Pathak
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata, India
| | - Sandip Dey
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata, India
| | - Sukanya Mozumder
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Jayati Sengupta
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India.
| |
Collapse
|
6
|
Babych M, Nguyen PT, Côté-Cyr M, Kihal N, Quittot N, Golizeh M, Sleno L, Bourgault S. Site-Specific Alkylation of the Islet Amyloid Polypeptide Accelerates Self-Assembly and Potentiates Perturbation of Lipid Membranes. Biochemistry 2021; 60:2285-2299. [PMID: 34264642 DOI: 10.1021/acs.biochem.1c00308] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The accumulation of insoluble amyloids in the pancreatic islets is a pathological hallmark of type II diabetes and correlates closely with the loss of β-cell mass. The predominant component of these amyloid deposits is the islet amyloid polypeptide (IAPP). The factors contributing to the conversion of IAPP from a monomeric bioactive peptide hormone into insoluble amyloid fibrils remain partially elusive. In this study, we investigated the effect of the oxidative non-enzymatic post-translational modification induced by the reactive metabolite 4-hydroxynonenal (HNE) on IAPP aggregation and cytotoxicity. Incubation of IAPP with exogenous HNE accelerated its self-assembly into β-sheet fibrils and led to the formation of a Michael adduct on the His-18 side chain. To model this covalent modification, the imidazole N(π) position of histidine was alkylated using a close analogue of HNE, the octyl chain. IAPP lipidated at His-18 showed a hastened random coil-to-β-sheet conformational conversion into fibrillar assemblies with a distinct morphology, a low level of binding to thioflavin T, and a high surface hydrophobicity. Introducing an octyl chain on His-18 enhanced the ability of the peptide to perturb synthetic lipid vesicles, to permeabilize the plasma membrane, and to induce the death of pancreatic β-cells. Alkylated IAPP triggered the self-assembly of unmodified IAPP by prompting primary nucleation and increased its capacity to perturb the plasma membrane, indicating that only a small proportion of the modified peptide is necessary to shift the balance toward the formation of proteotoxic species. This study underlines the importance of studying IAPP post-translational modifications induced by oxidative metabolites in the context of pancreatic amyloids.
Collapse
Affiliation(s)
- Margaryta Babych
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.,Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, http://proteo.ca/en/
| | - Phuong Trang Nguyen
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.,Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, http://proteo.ca/en/
| | - Mélanie Côté-Cyr
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.,Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, http://proteo.ca/en/
| | - Nadjib Kihal
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.,Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, http://proteo.ca/en/
| | - Noé Quittot
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.,Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, http://proteo.ca/en/
| | - Makan Golizeh
- Department of Mathematical and Physical Sciences, Concordia University of Edmonton, Edmonton, AB T5B 4E4, Canada
| | - Lekha Sleno
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada
| | - Steve Bourgault
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.,Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, http://proteo.ca/en/
| |
Collapse
|
7
|
Hanke M, Yang Y, Ji Y, Grundmeier G, Keller A. Nanoscale Surface Topography Modulates hIAPP Aggregation Pathways at Solid-Liquid Interfaces. Int J Mol Sci 2021; 22:ijms22105142. [PMID: 34067963 PMCID: PMC8152259 DOI: 10.3390/ijms22105142] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/07/2021] [Accepted: 05/11/2021] [Indexed: 01/11/2023] Open
Abstract
The effects that solid–liquid interfaces exert on the aggregation of proteins and peptides are of high relevance for various fields of basic and applied research, ranging from molecular biology and biomedicine to nanotechnology. While the influence of surface chemistry has received a lot of attention in this context, the role of surface topography has mostly been neglected so far. In this work, therefore, we investigate the aggregation of the type 2 diabetes-associated peptide hormone hIAPP in contact with flat and nanopatterned silicon oxide surfaces. The nanopatterned surfaces are produced by ion beam irradiation, resulting in well-defined anisotropic ripple patterns with heights and periodicities of about 1.5 and 30 nm, respectively. Using time-lapse atomic force microscopy, the morphology of the hIAPP aggregates is characterized quantitatively. Aggregation results in both amorphous aggregates and amyloid fibrils, with the presence of the nanopatterns leading to retarded fibrillization and stronger amorphous aggregation. This is attributed to structural differences in the amorphous aggregates formed at the nanopatterned surface, which result in a lower propensity for nucleating amyloid fibrillization. Our results demonstrate that nanoscale surface topography may modulate peptide and protein aggregation pathways in complex and intricate ways.
Collapse
|
8
|
Templin AT, Mellati M, Meier DT, Esser N, Hogan MF, Castillo JJ, Akter R, Raleigh DP, Zraika S, Hull RL, Kahn SE. Low concentration IL-1β promotes islet amyloid formation by increasing hIAPP release from humanised mouse islets in vitro. Diabetologia 2020; 63:2385-2395. [PMID: 32728889 PMCID: PMC7529980 DOI: 10.1007/s00125-020-05232-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/05/2020] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS Aggregation of the beta cell secretory product human islet amyloid polypeptide (hIAPP) results in islet amyloid deposition, a pathological feature of type 2 diabetes. Amyloid formation is associated with increased levels of islet IL-1β as well as beta cell dysfunction and death, but the mechanisms that promote amyloid deposition in situ remain unclear. We hypothesised that physiologically relevant concentrations of IL-1β stimulate beta cell islet amyloid polypeptide (IAPP) release and promote amyloid formation. METHODS We used a humanised mouse model of endogenous beta cell hIAPP expression to examine whether low (pg/ml) concentrations of IL-1β promote islet amyloid formation in vitro. Amyloid-forming islets were cultured for 48 h in the presence or absence of IL-1β with or without an IL-1β neutralising antibody. Islet morphology was assessed by immunohistochemistry and islet mRNA expression, hormone content and release were also quantified. Cell-free thioflavin T assays were used to monitor hIAPP aggregation kinetics in the presence and absence of IL-1β. RESULTS Treatment with a low concentration of IL-1β (4 pg/ml) for 48 h increased islet amyloid prevalence (93.52 ± 3.89% vs 43.83 ± 9.67% amyloid-containing islets) and amyloid severity (4.45 ± 0.82% vs 2.16 ± 0.50% amyloid area/islet area) in hIAPP-expressing mouse islets in vitro. This effect of IL-1β was reduced when hIAPP-expressing islets were co-treated with an IL-1β neutralising antibody. Cell-free hIAPP aggregation assays showed no effect of IL-1β on hIAPP aggregation in vitro. Low concentration IL-1β did not increase markers of the unfolded protein response (Atf4, Ddit3) or alter proIAPP processing enzyme gene expression (Pcsk1, Pcsk2, Cpe) in hIAPP-expressing islets. However, release of IAPP and insulin were increased over 48 h in IL-1β-treated vs control islets (IAPP 0.409 ± 0.082 vs 0.165 ± 0.051 pmol/5 islets; insulin 87.5 ± 8.81 vs 48.3 ± 17.3 pmol/5 islets), and this effect was blocked by co-treatment with IL-1β neutralising antibody. CONCLUSIONS/INTERPRETATION Under amyloidogenic conditions, physiologically relevant levels of IL-1β promote islet amyloid formation by increasing beta cell release of IAPP. Neutralisation of this effect of IL-1β may decrease the deleterious effects of islet amyloid formation on beta cell function and survival.
Collapse
Affiliation(s)
- Andrew T Templin
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Mahnaz Mellati
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Daniel T Meier
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Nathalie Esser
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Meghan F Hogan
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Joseph J Castillo
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Rehana Akter
- Department of Chemistry, Stony Brook University, Stony Brook, NY, USA
| | - Daniel P Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, NY, USA
| | - Sakeneh Zraika
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Rebecca L Hull
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Steven E Kahn
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA.
| |
Collapse
|
9
|
Wu MH, Chan AC, Tu LH. Role of lysine residue of islet amyloid polypeptide in fibril formation, membrane binding, and inhibitor binding. Biochimie 2020; 177:153-163. [PMID: 32860895 DOI: 10.1016/j.biochi.2020.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/31/2020] [Accepted: 08/18/2020] [Indexed: 12/27/2022]
Abstract
The aggregation of islet amyloid polypeptide (IAPP) is implicated in the pathogenesis of type 2 diabetes (T2D). In T2D, this peptide aggregates to form amyloid fibrils; the mechanism responsible for islet amyloid formation is unclear. However, it is known that the aggregation propensity of IAPP is highly related to its primary sequence. Several residues have been suggested to be critical in modulating IAPP amyloid formation, but role of the sole lysine residue at position 1 (Lys-1) in IAPP has not been discussed. In our previous study, we found that glycated IAPP can form amyloid faster than normal IAPP and induce normal IAPP to expedite the aggregation process. To gain more insight into the contribution of Lys-1 in the kinetics of fibril formation, we synthesized another two IAPP variants, K1E-IAPP and K1Nle-IAPP, in which the Lys residue was mutated to glutamate and norleucine, respectively. Interestingly, we observed that the negative or neutral charged side chain at this position was preferred for amyloid formation. The findings suggested this residue may take part in the inter- or intra-molecular interaction during IAPP aggregation, even though it was proposed not to be in part of fibril core structure. Our data also revealed that the inhibitory mechanism of some inhibitors for IAPP aggregation require reaction with Lys-1. Modifications of Lys-1, such as protein glycation, may affect the effectiveness of the inhibitory action of some potential drugs in the treatment of amyloidosis.
Collapse
Affiliation(s)
- Meng-Hsin Wu
- Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan
| | - Ai-Ci Chan
- Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan
| | - Ling-Hsien Tu
- Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan.
| |
Collapse
|
10
|
Chen YC, Mains RE, Eipper BA, Hoffman BG, Czyzyk TA, Pintar JE, Verchere CB. PAM haploinsufficiency does not accelerate the development of diet- and human IAPP-induced diabetes in mice. Diabetologia 2020; 63:561-576. [PMID: 31984442 PMCID: PMC7864590 DOI: 10.1007/s00125-019-05060-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Accepted: 10/28/2019] [Indexed: 12/17/2022]
Abstract
AIMS/HYPOTHESIS Peptide hormones are first synthesised as larger, inactive precursors that are converted to their active forms by endopeptidase cleavage and post-translational modifications, such as amidation. Recent, large-scale genome-wide studies have suggested that two coding variants of the amidating enzyme, peptidylglycine α-amidating monooxygenase (PAM), are associated with impaired insulin secretion and increased type 2 diabetes risk. We aimed to elucidate the role of PAM in modulating beta cell peptide amidation, beta cell function and the development of diabetes. METHODS PAM transcript and protein levels were analysed in mouse islets following induction of endoplasmic reticulum (ER) or cytokine stress, and PAM expression patterns were examined in human islets. To study whether haploinsufficiency of PAM accelerates the development of diabetes, Pam+/- and Pam+/+ mice were fed a low-fat diet (LFD) or high-fat diet (HFD) and glucose homeostasis was assessed. Since aggregates of the PAM substrate human islet amyloid polypeptide (hIAPP) lead to islet inflammation and beta cell failure, we also investigated whether PAM haploinsufficiency accelerated hIAPP-induced diabetes and islet amyloid formation in Pam+/- and Pam+/+ mice with beta cell expression of hIAPP. RESULTS Immunostaining revealed high expression of PAM in alpha, beta and delta cells in human pancreatic islets. Pam mRNA and PAM protein expression were reduced in mouse islets following administration of an HFD, and in isolated islets following induction of ER stress with thapsigargin, or cytokine stress with IL-1β, IFN-γ and TFN-α. Despite Pam+/- only having 50% PAM expression and enzyme activity as compared with Pam+/+ mice, glucose tolerance and body mass composition were comparable in the two models. After 24 weeks of HFD, both Pam+/- and Pam+/+ mice had insulin resistance and impaired glucose tolerance, but no differences in glucose tolerance, insulin sensitivity or plasma insulin levels were observed in PAM haploinsufficient mice. Islet amyloid formation and beta cell function were also similar in Pam+/- and Pam+/+ mice with beta cell expression of hIAPP. CONCLUSIONS/INTERPRETATION Haploinsufficiency of PAM in mice does not accelerate the development of diet-induced obesity or hIAPP transgene-induced diabetes.
Collapse
MESH Headings
- Amidine-Lyases/genetics
- Amidine-Lyases/physiology
- Animals
- Cells, Cultured
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Disease Progression
- Epistasis, Genetic/physiology
- Female
- Genetic Predisposition to Disease
- Haploinsufficiency
- Humans
- Insulin-Secreting Cells/metabolism
- Insulin-Secreting Cells/pathology
- Islet Amyloid Polypeptide/genetics
- Islet Amyloid Polypeptide/physiology
- Islets of Langerhans/metabolism
- Islets of Langerhans/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Mixed Function Oxygenases/genetics
- Mixed Function Oxygenases/physiology
- Rats
- Rats, Inbred Lew
- Risk Factors
Collapse
Affiliation(s)
- Yi-Chun Chen
- Department of Surgery, University of British Columbia and BC Children's Hospital Research Institute, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA
| | - Betty A Eipper
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT, USA
| | - Brad G Hoffman
- Department of Surgery, University of British Columbia and BC Children's Hospital Research Institute, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada
| | - Traci A Czyzyk
- Division of Cardio-renal and Metabolic Disease, Merck Research Laboratories, San Francisco, CA, USA
| | - John E Pintar
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - C Bruce Verchere
- Department of Surgery, University of British Columbia and BC Children's Hospital Research Institute, 950 West 28th Avenue, Vancouver, BC, V5Z 4H4, Canada.
- Department of Pathology and Laboratory Medicine, University of British Columbia and BC Children's Hospital Research Institute, Vancouver, BC, Canada.
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC, Canada.
| |
Collapse
|
11
|
Lee KH, Zhyvoloup A, Raleigh D. Amyloidogenicity and cytotoxicity of des-Lys-1 human amylin provides insight into amylin self-assembly and highlights the difficulties of defining amyloidogenicity. Protein Eng Des Sel 2019; 32:87-93. [PMID: 31768548 PMCID: PMC6908818 DOI: 10.1093/protein/gzz036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 07/11/2019] [Accepted: 07/31/2019] [Indexed: 12/27/2022] Open
Abstract
The polypeptide amylin is responsible for islet amyloid in type 2 diabetes, a process which contributes to β-cell death in the disease. The role of the N-terminal region of amylin in amyloid formation is relatively unexplored, although removal of the disulfide bridged loop between Cys-2 and Cys-7 accelerates amyloid formation. We examine the des Lys-1 variant of human amylin (h-amylin), a variant which is likely produced in vivo. Lys-1 is a region of high charge density in the h-amylin amyloid fiber. The des Lys-1 polypeptide forms amyloid on the same time scale as wild-type amylin in phosphate buffered saline, but does so more rapidly in Tris. The des Lys-1 variant is somewhat less toxic to cultured INS cells than wild type. The implications for the in vitro mechanism of amyloid formation and for comparative analysis of amyloidogenicity are discussed.
Collapse
Affiliation(s)
- Kyung-Hoon Lee
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11790-3400, USA
| | - Alexander Zhyvoloup
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E6BT, UK, and
| | - Daniel Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11790-3400, USA
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E6BT, UK, and
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY 11790-3400, USA
| |
Collapse
|
12
|
Hsu YH, Chen YW, Wu MH, Tu LH. Protein Glycation by Glyoxal Promotes Amyloid Formation by Islet Amyloid Polypeptide. Biophys J 2019; 116:2304-2313. [PMID: 31155148 DOI: 10.1016/j.bpj.2019.05.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 04/16/2019] [Accepted: 05/14/2019] [Indexed: 01/01/2023] Open
Abstract
Protein glycation, also known as nonenzymatic glycosylation, is a spontaneous post-translational modification that would change the structure and stability of proteins or hormone peptides. Recent studies have indicated that glycation plays a role in type 2 diabetes (T2D) and neurodegenerative diseases. Over the last two decades, many types of advanced glycation end products (AGEs), formed through the reactions of an amino group of proteins with reducing sugars, have been identified and detected in vivo. However, the effect of glycation on protein aggregation has not been fully investigated. In this study, we aim to elucidate the impact of protein glycation on islet amyloid polypeptide (IAPP, also known as amylin) aggregation, which was strongly associated with T2D. We chemically synthesized glycated IAPP (AGE-IAPP) to mimic the consequence of this hormone peptide in a hyperglycemia (high blood sugar) environment. Our data revealed that AGE-IAPP formed amyloid faster than normal IAPP, and higher-molecular-weight AGE-IAPP oligomers were also observed in the early stage of aggregation. Circular dichroism spectra also indicated that AGE-IAPP exhibited faster conformational changes from random coil to its β-sheet fibrillar states. Moreover, AGE-IAPP can induce normal IAPP to expedite its aggregation process, and its fibrils can also act as templates to promote IAPP aggregation. AGE-IAPP, like normal IAPP, is capable of interacting with synthetic membranes and also exhibits cytotoxicity. Our studies demonstrated that glycation modification of IAPP promotes the amyloidogenic properties of IAPP, and it may play a role in accumulating additional amyloid during T2D progression.
Collapse
Affiliation(s)
- Yi-Hsuan Hsu
- Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan
| | - Yun-Wen Chen
- Department of Pharmacology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Meng-Hsin Wu
- Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan
| | - Ling-Hsien Tu
- Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan.
| |
Collapse
|
13
|
Bower RL, Yule L, Rees TA, Deganutti G, Hendrikse ER, Harris PWR, Kowalczyk R, Ridgway Z, Wong AG, Swierkula K, Raleigh DP, Pioszak AA, Brimble MA, Reynolds CA, Walker CS, Hay DL. Molecular Signature for Receptor Engagement in the Metabolic Peptide Hormone Amylin. ACS Pharmacol Transl Sci 2018; 1:32-49. [PMID: 32219203 DOI: 10.1021/acsptsci.8b00002] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Indexed: 11/30/2022]
Abstract
The pancreatic peptide hormone, amylin, plays a critical role in the control of appetite, and synergizes with other key metabolic hormones such as glucagon-like peptide 1 (GLP-1). There is opportunity to develop potent and long-acting analogues of amylin or hybrids between these and GLP-1 mimetics for treating obesity. To achieve this, interrogation of how the 37 amino acid amylin peptide engages with its complex receptor system is required. We synthesized an extensive library of peptides to profile the human amylin sequence, determining the role of its disulfide loop, amidated C-terminus and receptor "capture" and "activation" regions in receptor signaling. We profiled four signaling pathways with different ligands at multiple receptor subtypes, in addition to exploring selectivity determinants between related receptors. Distinct roles for peptide subregions in receptor binding and activation were identified, resulting in peptides with greater activity than the native sequence. Enhanced peptide activity was preserved in the brainstem, the major biological target for amylin. Interpretation of our data using full-length active receptor models supported by molecular dynamics, metadynamics, and supervised molecular dynamics simulations guided the synthesis of a potent dual agonist of GLP-1 and amylin receptors. The data offer new insights into the function of peptide amidation, how allostery drives peptide-receptor interactions, and provide a valuable resource for the development of novel amylin agonists for treating diabetes and obesity.
Collapse
Affiliation(s)
- Rebekah L Bower
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Lauren Yule
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Tayla A Rees
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Giuseppe Deganutti
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K
| | - Erica R Hendrikse
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Paul W R Harris
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Renata Kowalczyk
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Zachary Ridgway
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Amy G Wong
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Katarzyna Swierkula
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K
| | - Daniel P Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States.,Department of Structural and Molecular Biology, University College London, London WC1E 6BT, U.K
| | - Augen A Pioszak
- Department of Biochemistry and Molecular Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, United States
| | - Margaret A Brimble
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Christopher A Reynolds
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, U.K
| | - Christopher S Walker
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| | - Debbie L Hay
- School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand.,School of Biological Sciences, School of Chemical Sciences, and Maurice Wilkins Centre, The University of Auckland, Auckland, 1010, New Zealand
| |
Collapse
|
14
|
Quittot N, Sebastiao M, Al-Halifa S, Bourgault S. Kinetic and Conformational Insights into Islet Amyloid Polypeptide Self-Assembly Using a Biarsenical Fluorogenic Probe. Bioconjug Chem 2018; 29:517-527. [DOI: 10.1021/acs.bioconjchem.7b00827] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Noé Quittot
- Department of Chemistry, Quebec Network
for Research on Protein Function, Engineering and Applications, PROTEO, University of Québec in Montreal, C.P. 8888, Succursale Centre-Ville, Montreal, Québec H3C 3P8, Canada
| | - Mathew Sebastiao
- Department of Chemistry, Quebec Network
for Research on Protein Function, Engineering and Applications, PROTEO, University of Québec in Montreal, C.P. 8888, Succursale Centre-Ville, Montreal, Québec H3C 3P8, Canada
| | - Soultan Al-Halifa
- Department of Chemistry, Quebec Network
for Research on Protein Function, Engineering and Applications, PROTEO, University of Québec in Montreal, C.P. 8888, Succursale Centre-Ville, Montreal, Québec H3C 3P8, Canada
| | - Steve Bourgault
- Department of Chemistry, Quebec Network
for Research on Protein Function, Engineering and Applications, PROTEO, University of Québec in Montreal, C.P. 8888, Succursale Centre-Ville, Montreal, Québec H3C 3P8, Canada
| |
Collapse
|
15
|
Ho JJ, Ghosh A, Zhang TO, Zanni MT. Heterogeneous Amyloid β-Sheet Polymorphs Identified on Hydrogen Bond Promoting Surfaces Using 2D SFG Spectroscopy. J Phys Chem A 2018; 122:1270-1282. [DOI: 10.1021/acs.jpca.7b11934] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Jia-Jung Ho
- University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Ayanjeet Ghosh
- University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Tianqi O. Zhang
- University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Martin T. Zanni
- University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| |
Collapse
|
16
|
Maj M, Lomont JP, Rich KL, Alperstein AM, Zanni MT. Site-specific detection of protein secondary structure using 2D IR dihedral indexing: a proposed assembly mechanism of oligomeric hIAPP. Chem Sci 2018; 9:463-474. [PMID: 29619202 PMCID: PMC5868010 DOI: 10.1039/c7sc03789a] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/02/2017] [Indexed: 12/19/2022] Open
Abstract
Human islet amyloid polypeptide (hIAPP) aggregates into fibrils through oligomers that have been postulated to contain α-helices as well as β-sheets. We employ a site-specific isotope labeling strategy that is capable of detecting changes in dihedral angles when used in conjunction with 2D IR spectroscopy. The method is analogous to the chemical shift index used in NMR spectroscopy for assigning protein secondary structure. We introduce isotope labels at two neighbouring residues, which results in an increased intensity and positive frequency shift if those residues are α-helical versus a negative frequency shift in β-sheets and turns. The 2D IR dihedral index approach is demonstrated for hIAPP in micelles for which the polypeptide structure is known, using pairs of 13C18O isotope labels L12A13 and L16V17, along with single labeled control experiments. Applying the approach to aggregation experiments performed in buffer, we show that about 27-38% of hIAPP peptides adopt an α-helix secondary structure in the monomeric state at L12A13, prior to aggregation, but not at L16V17 residues. At L16V17, the kinetics are described solely by the monomer and fiber conformations, but at L12A13 the kinetics exhibit a third state that is created by an oligomeric intermediate. Control experiments performed with a single isotope label at A13 exhibit two-state kinetics, indicating that a previously unknown change in dihedral angle occurs at L12A13 as hIAPP transitions from the intermediate to fiber structures. We propose a mechanism for aggregation, in which helices seed oligomer formation via structures analogous to leucine rich repeat proteins.
Collapse
Affiliation(s)
- Michał Maj
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706-1396 , USA .
| | - Justin P Lomont
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706-1396 , USA .
| | - Kacie L Rich
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706-1396 , USA .
| | - Ariel M Alperstein
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706-1396 , USA .
| | - Martin T Zanni
- Department of Chemistry , University of Wisconsin-Madison , Madison , Wisconsin 53706-1396 , USA .
| |
Collapse
|
17
|
Khemtemourian L, Guillemain G, Foufelle F, Killian JA. Residue specific effects of human islet polypeptide amyloid on self-assembly and on cell toxicity. Biochimie 2017; 142:22-30. [DOI: 10.1016/j.biochi.2017.07.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/29/2017] [Indexed: 12/24/2022]
|
18
|
Young LM, Tu LH, Raleigh DP, Ashcroft AE, Radford SE. Understanding co-polymerization in amyloid formation by direct observation of mixed oligomers. Chem Sci 2017; 8:5030-5040. [PMID: 28970890 PMCID: PMC5613229 DOI: 10.1039/c7sc00620a] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/03/2017] [Indexed: 12/15/2022] Open
Abstract
Although amyloid assembly in vitro is commonly investigated using single protein sequences, fibril formation in vivo can be more heterogeneous, involving co-assembly of proteins of different length, sequence and/or post-translational modifications. Emerging evidence suggests that co-polymerization can alter the rate and/or mechanism of aggregation and can contribute to pathogenicity. Electrospray ionization-ion mobility spectrometry-mass spectrometry (ESI-IMS-MS) is uniquely suited to the study of these heterogeneous ensembles. Here, ESI-IMS-MS combined with analysis of fibrillation rates using thioflavin T (ThT) fluorescence, is used to track the course of aggregation of variants of islet-amyloid polypeptide (IAPP) in isolation and in pairwise mixtures. We identify a sub-population of extended monomers as the key precursors of amyloid assembly, and reveal that the fastest aggregating sequence in peptide mixtures determines the lag time of fibrillation, despite being unable to cross-seed polymerization. The results demonstrate that co-polymerization of IAPP sequences radically alters the rate of amyloid assembly by altering the conformational properties of the mixed oligomers that form.
Collapse
Affiliation(s)
- Lydia M Young
- Astbury Centre for Structural Molecular Biology , School of Molecular and Cellular Biology , University of Leeds , Leeds LS2 9JT , UK .
| | - Ling-Hsien Tu
- Department of Chemistry , Stony Brook University , Stony Brook , New York 11794-3400 , USA
- Genomics Research Center , Academia Sinica , 128 Academia , Taipei 11529 , Taiwan
| | - Daniel P Raleigh
- Department of Chemistry , Stony Brook University , Stony Brook , New York 11794-3400 , USA
| | - Alison E Ashcroft
- Astbury Centre for Structural Molecular Biology , School of Molecular and Cellular Biology , University of Leeds , Leeds LS2 9JT , UK .
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology , School of Molecular and Cellular Biology , University of Leeds , Leeds LS2 9JT , UK .
| |
Collapse
|
19
|
Tracking the amyloidogenic core of IAPP amyloid fibrils: Insights from micro-Raman spectroscopy. J Struct Biol 2017; 199:140-152. [PMID: 28602716 DOI: 10.1016/j.jsb.2017.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/19/2017] [Accepted: 06/03/2017] [Indexed: 12/14/2022]
Abstract
Human islet amyloid polypeptide (hIAPP) is the major protein component of extracellular amyloid deposits, located in the islets of Langerhans, a hallmark of type II diabetes. The underlying mechanisms of IAPP aggregation have not yet been clearly defined, although the highly amyloidogenic sequence of the protein has been extensively studied. Several segments have been highlighted as aggregation-prone regions (APRs), with much attention focused on the central 8-17 and 20-29 stretches. In this work, we employ micro-Raman spectroscopy to identify specific regions that are contributing to or are excluded from the amyloidogenic core of IAPP amyloid fibrils. Our results demonstrate that both the N-terminal region containing a conserved disulfide bond between Cys residues at positions 2 and 7, and the C-terminal region containing the only Tyr residue are excluded from the amyloid core. Finally, by performing detailed aggregation assays and molecular dynamics simulations on a number of IAPP variants, we demonstrate that point mutations within the central APRs contribute to the reduction of the overall amyloidogenic potential of the protein but do not completely abolish the formation of IAPP amyloid fibrils.
Collapse
|
20
|
Tran L, Ha-Duong T. Effect of Post-Translational Amidation on Islet Amyloid Polypeptide Conformational Ensemble: Implications for Its Aggregation Early Steps. Int J Mol Sci 2016; 17:ijms17111896. [PMID: 27854243 PMCID: PMC5133895 DOI: 10.3390/ijms17111896] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/02/2016] [Accepted: 11/09/2016] [Indexed: 12/21/2022] Open
Abstract
The human islet amyloid polypeptide (hIAPP) is an intrinsically disordered protein that can self-assemble into fibrillar aggregates that play a key role in the pathogenesis of the type II diabetes mellitus. hIAPP can transiently adopt α-helix and β-strand conformations that could be important intermediate species on the fibrillization pathway. However, experimental studies of the monomeric peptide conformations are limited due to its high aggregation propensity, and the early steps of the hIAPP association are not clearly characterized. In particular, the question of whether the aggregation-prone conformation is α-helical or β-strand-rich is still debated. In this study, combining extensive all-atom molecular dynamics (MD) and replica exchange molecular dynamics (REMD) simulations in explicit water, we shed some light on the differences between the amidated and non-amidated hIAPP conformational ensembles. Our study shows that, when compared to the amidated monomer, the non-amidation of hIAPP induces a significantly lower propensity to form β-strands, especially aggregation-prone β-hairpins. Since the fibrillization of the non-amidated hIAPP is significantly slower than that of the amidated peptide, this indicates that the early steps of the peptide oligomerization involve the association of β-hairpins or β-strands structures.
Collapse
Affiliation(s)
- Linh Tran
- BioCIS, Université Paris-Sud, CNRS, Université Paris-Saclay, 92290 Châtenay-Malabry, France.
| | - Tâp Ha-Duong
- BioCIS, Université Paris-Sud, CNRS, Université Paris-Saclay, 92290 Châtenay-Malabry, France.
| |
Collapse
|
21
|
Zhang X, Liu J, Huang L, Yang X, Petersen RB, Sun Y, Gong H, Zheng L, Huang K. How the imidazole ring modulates amyloid formation of islet amyloid polypeptide: A chemical modification study. Biochim Biophys Acta Gen Subj 2016; 1860:719-26. [DOI: 10.1016/j.bbagen.2016.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 12/18/2015] [Accepted: 01/13/2016] [Indexed: 11/25/2022]
|
22
|
Akter R, Cao P, Noor H, Ridgway Z, Tu LH, Wang H, Wong AG, Zhang X, Abedini A, Schmidt AM, Raleigh DP. Islet Amyloid Polypeptide: Structure, Function, and Pathophysiology. J Diabetes Res 2015; 2016:2798269. [PMID: 26649319 PMCID: PMC4662979 DOI: 10.1155/2016/2798269] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/24/2015] [Indexed: 01/29/2023] Open
Abstract
The hormone islet amyloid polypeptide (IAPP, or amylin) plays a role in glucose homeostasis but aggregates to form islet amyloid in type-2 diabetes. Islet amyloid formation contributes to β-cell dysfunction and death in the disease and to the failure of islet transplants. Recent work suggests a role for IAPP aggregation in cardiovascular complications of type-2 diabetes and hints at a possible role in type-1 diabetes. The mechanisms of IAPP amyloid formation in vivo or in vitro are not understood and the mechanisms of IAPP induced β-cell death are not fully defined. Activation of the inflammasome, defects in autophagy, ER stress, generation of reactive oxygen species, membrane disruption, and receptor mediated mechanisms have all been proposed to play a role. Open questions in the field include the relative importance of the various mechanisms of β-cell death, the relevance of reductionist biophysical studies to the situation in vivo, the molecular mechanism of amyloid formation in vitro and in vivo, the factors which trigger amyloid formation in type-2 diabetes, the potential role of IAPP in type-1 diabetes, the development of clinically relevant inhibitors of islet amyloidosis toxicity, and the design of soluble, bioactive variants of IAPP for use as adjuncts to insulin therapy.
Collapse
Affiliation(s)
- Rehana Akter
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Ping Cao
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Harris Noor
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Zachary Ridgway
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Ling-Hsien Tu
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Hui Wang
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Amy G. Wong
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Xiaoxue Zhang
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Andisheh Abedini
- Diabetes Research Program, NYU School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Ann Marie Schmidt
- Diabetes Research Program, NYU School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Daniel P. Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
- Research Department of Structural and Molecule Biology, University College London, Gower Street, London WC1E 6BT, UK
| |
Collapse
|
23
|
Wang H, Ridgway Z, Cao P, Ruzsicska B, Raleigh DP. Analysis of the ability of pramlintide to inhibit amyloid formation by human islet amyloid polypeptide reveals a balance between optimal recognition and reduced amyloidogenicity. Biochemistry 2015; 54:6704-11. [PMID: 26407043 DOI: 10.1021/acs.biochem.5b00567] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The hormone human islet amyloid polypeptide (hIAPP or amylin) plays a role in glucose metabolism, but forms amyloid in the pancreas in type 2 diabetes (T2D) and is associated with β-cell death and dysfunction in the disease. Inhibitors of islet amyloid have therapeutic potential; however, there are no clinically approved inhibitors, and the mode of action of existing inhibitors is not well understood. Rat IAPP (rIAPP) differs from hIAPP at six positions, does not form amyloid, and is an inhibitor of amyloid formation by hIAPP. Five of the six differences are located within the segment of residues 20-29, and three of them are Pro residues, which are well-known disruptors of β-sheet structure. rIAPP is thus a natural example of a "β-breaker inhibitor", a molecule that combines a recognition element with an entity that inhibits β-sheet formation. Pramlintide (PM) is a peptide drug approved for use as an adjunct to insulin therapy for treatment of diabetes. PM was developed by introducing the three Pro substitutions found in rIAPP into hIAPP. Thus, it more closely resembles the human peptide than does rIAPP. Here we examine and compare the ability of rIAPP, PM, and a set of designed analogues of hIAPP to inhibit amyloid formation by hIAPP, to elucidate the factors that lead to effective peptide-based inhibitors. Our results reveal, for this class of molecules, a balance between the reduced amyloidogenicity of the inhibitory sequence on one hand and its ability to recognize hIAPP on the other.
Collapse
Affiliation(s)
- Hui Wang
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States
| | - Zachary Ridgway
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States
| | - Ping Cao
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States.,Structural Biology Program, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine , New York, New York 10016, United States
| | - Bela Ruzsicska
- Institute for Chemical Biology and Drug Discovery, Stony Brook University , Stony Brook, New York 11794-3400, United States
| | - Daniel P Raleigh
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States.,Institute for Chemical Biology and Drug Discovery, Stony Brook University , Stony Brook, New York 11794-3400, United States.,Graduate Program in Biochemistry and Structural Biology, Graduate Program in Biophysics, Stony Brook University , Stony Brook, New York 11794-3400, United States.,Research Department of Structural and Molecular Biology, University College London , Gower Street, London WC1E 6BT, U.K
| |
Collapse
|
24
|
Young LM, Mahood RA, Saunders JC, Tu LH, Raleigh DP, Radford SE, Ashcroft AE. Insights into the consequences of co-polymerisation in the early stages of IAPP and Aβ peptide assembly from mass spectrometry. Analyst 2015; 140:6990-9. [PMID: 26193839 PMCID: PMC4626081 DOI: 10.1039/c5an00865d] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The precise molecular mechanisms by which different peptides and proteins assemble into highly ordered amyloid deposits remain elusive. The fibrillation of human amylin (also known as islet amyloid polypeptide, hIAPP) and the amyloid-beta peptide (Aβ-40) are thought to be pathogenic factors in Type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD), respectively. Amyloid diseases may involve co-aggregation of different protein species, in addition to the self-assembly of single precursor sequences. Here we investigate the formation of heterogeneous pre-fibrillar, oligomeric species produced by the co-incubation of hIAPP and Aβ-40 using electrospray ionisation-ion mobility spectrometry-mass spectrometry (ESI-IMS-MS)-based methods. Conformational properties and gas-phase stabilities of amyloid oligomers formed from hIAPP or Aβ40 alone, and from a 1 : 1 mixture of hIAPP and Aβ40 monomers, were determined and compared. We show that co-assembly of the two sequences results in hetero-oligomers with distinct properties and aggregation kinetics properties compared with the homo-oligomers present in solution. The observations may be of key significance to unravelling the mechanisms of amyloid formation in vivo and elucidating how different sequences and/or assembly conditions can result in different fibril structures and/or pathogenic outcomes.
Collapse
Affiliation(s)
- Lydia M. Young
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK
| | - Rachel A. Mahood
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK
| | - Janet C. Saunders
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK
| | - Ling-Hsien Tu
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, USA
| | - Daniel P. Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, USA
- Research Department of Structural and Molecule Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Sheena E. Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK
| | - Alison E. Ashcroft
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, LS2 9JT, UK
| |
Collapse
|
25
|
Brender JR, Krishnamoorthy J, Sciacca MFM, Vivekanandan S, D'Urso L, Chen J, La Rosa C, Ramamoorthy A. Probing the sources of the apparent irreproducibility of amyloid formation: drastic changes in kinetics and a switch in mechanism due to micellelike oligomer formation at critical concentrations of IAPP. J Phys Chem B 2015; 119:2886-96. [PMID: 25645610 DOI: 10.1021/jp511758w] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The aggregation of amyloidogenic proteins is infamous for being highly chaotic, with small variations in conditions sometimes leading to large changes in aggregation rates. Using the amyloidogenic protein IAPP (islet amyloid polypeptide protein, also known as amylin) as an example, we show that a part of this phenomenon may be related to the formation of micellelike oligomers at specific critical concentrations and temperatures. We show that pyrene fluorescence can sensitively detect micellelike oligomer formation by IAPP and discriminate between micellelike oligomers from fibers and monomers, making pyrene one of the few chemical probes specific to a prefibrillar oligomer. We further show that oligomers of this type reversibly form at critical concentrations in the low micromolar range and at specific critical temperatures. Micellelike oligomer formation has several consequences for amyloid formation by IAPP. First, the kinetics of fiber formation increase substantially as the critical concentration is approached but are nearly independent of concentration below it, suggesting a direct role for the oligomers in fiber formation. Second, the critical concentration is strongly correlated with the propensity to form amyloid: higher critical concentrations are observed for both IAPP variants with lower amyloidogenicity and for native IAPP at acidic pH in which aggregation is greatly slowed. Furthermore, using the DEST NMR technique, we show that the pathway of amyloid formation switches as the critical point is approached, with self-interactions primarily near the N-terminus below the critical temperature and near the central region above the critical temperature, reconciling two apparently conflicting views of the initiation of IAPP aggregation.
Collapse
Affiliation(s)
- Jeffrey R Brender
- Biophysics, University of Michigan , Ann Arbor, Michigan 48109-1055, United States
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Tu LH, Young LM, Wong AG, Ashcroft AE, Radford SE, Raleigh DP. Mutational analysis of the ability of resveratrol to inhibit amyloid formation by islet amyloid polypeptide: critical evaluation of the importance of aromatic-inhibitor and histidine-inhibitor interactions. Biochemistry 2015; 54:666-76. [PMID: 25531836 PMCID: PMC4310630 DOI: 10.1021/bi501016r] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The process of amyloid formation by the normally soluble hormone islet amyloid polypeptide (IAPP) contributes to β-cell death in type 2 diabetes and in islet transplants. There are no clinically approved inhibitors of islet amyloidosis, and the mode of action of existing inhibitors is not well-understood. Resveratrol, a natural polyphenol, has been reported to inhibit amyloid formation by IAPP and by the Alzheimer's disease Aβ peptide. The mechanism of action of this compound is not known, nor is its mode of interaction with IAPP. In this study, we use a series of IAPP variants to examine possible interactions between resveratrol and IAPP. Fluorescence assays, transmission electron microscopy, and mass spectrometry demonstrate that resveratrol is much less effective as an inhibitor of IAPP amyloid formation than the polyphenol (-)-epigallocatechin 3-gallate (EGCG) and, unlike EGCG, does not significantly disaggregate preformed IAPP amyloid fibrils. Resveratrol is also shown to interfere with thioflavin-T assays. His-18 mutants, a truncation mutant, mutants of each of the aromatic residues, and mutants of Arg-11 of IAPP were examined. Mutation of His to Gln or Leu weakens the ability of resveratrol to inhibit amyloid formation by IAPP, as do mutations of Arg-11, Phe-15, or Tyr-37 to Leu, and truncation to form the variant Ac 8-37-IAPP, which removes the first seven residues to eliminate Lys-1 and the N-terminal amino group. In contrast, replacement of Phe-23 with Leu has a smaller effect. The data highlight Phe-15, His-18, and Tyr-37 as being important for IAPP-resveratrol interactions and are consistent with a potential role of the N-terminus and Arg-11 in polypeptide-resveratrol interactions.
Collapse
Affiliation(s)
- Ling-Hsien Tu
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States
| | | | | | | | | | | |
Collapse
|
27
|
Andreasen M, Skeby KK, Zhang S, Nielsen EH, Klausen LH, Frahm H, Christiansen G, Skrydstrup T, Dong M, Schiøtt B, Otzen D. The Importance of Being Capped: Terminal Capping of an Amyloidogenic Peptide Affects Fibrillation Propensity and Fibril Morphology. Biochemistry 2014; 53:6968-80. [DOI: 10.1021/bi500674u] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maria Andreasen
- Interdisciplinary
Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus, Denmark
- Center
for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience
Center (iNANO) at the Department of Molecular Biology, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark
| | - Katrine Kirkeby Skeby
- Center
for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience
Center (iNANO) at the Department of Chemistry, Aarhus University, Langelandsgade
140, DK-8000 Aarhus, Denmark
| | - Shuai Zhang
- Interdisciplinary
Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus, Denmark
| | - Erik Holm Nielsen
- Interdisciplinary
Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus, Denmark
- Center
for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience
Center (iNANO) at the Department of Chemistry, Aarhus University, Langelandsgade
140, DK-8000 Aarhus, Denmark
| | - Lasse Hyldgaard Klausen
- Interdisciplinary
Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus, Denmark
| | - Heidi Frahm
- Interdisciplinary
Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus, Denmark
- Center
for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience
Center (iNANO) at the Department of Molecular Biology, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark
| | - Gunna Christiansen
- Department
of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, DK-8000 Aarhus, Denmark
| | - Troels Skrydstrup
- Interdisciplinary
Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus, Denmark
- Center
for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience
Center (iNANO) at the Department of Chemistry, Aarhus University, Langelandsgade
140, DK-8000 Aarhus, Denmark
| | - Mingdong Dong
- Interdisciplinary
Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus, Denmark
| | - Birgit Schiøtt
- Center
for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience
Center (iNANO) at the Department of Chemistry, Aarhus University, Langelandsgade
140, DK-8000 Aarhus, Denmark
| | - Daniel Otzen
- Interdisciplinary
Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus, Denmark
- Center
for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience
Center (iNANO) at the Department of Molecular Biology, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark
| |
Collapse
|
28
|
Wang H, Abedini A, Ruzsicska B, Raleigh DP. Rationally designed, nontoxic, nonamyloidogenic analogues of human islet amyloid polypeptide with improved solubility. Biochemistry 2014; 53:5876-84. [PMID: 25140605 PMCID: PMC4172205 DOI: 10.1021/bi500592p] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
![]()
Human
islet amyloid polypeptide (hIAPP or amylin) is a polypeptide
hormone produced in the pancreatic β-cells that plays a role
in glycemic control. hIAPP is deficient in type 1 and type 2 diabetes
and is a promising adjunct to insulin therapy. However, hIAPP rapidly
forms amyloid, and its strong tendency to aggregate limits its usefulness.
The process of hIAPP amyloid formation is toxic to cultured β-cells
and islets, and islet amyloid formation in vivo has
been linked to β-cell death and islet graft failure. An analogue
of hIAPP with a weakened tendency to aggregate, denoted pramlintide
(PM), has been approved for clinical applications, but suffers from
poor solubility, particularly at physiological pH, and its unfavorable
solubility profile prevents coformulation with insulin. We describe
a strategy for rationally designing analogues
of hIAPP with improved properties; key proline mutations are combined
with substitutions that increase the net charge of the molecule. An
H18R/G24P/I26P triple mutant and an H18R/A25P/S28P/S29P quadruple
mutant are significantly more soluble at neutral pH than hIAPP or
PM. They are nonamyloidogenic and are not toxic to rat INS β-cells.
The approach is not limited
to these examples; additional analogues can be designed using this
strategy. To illustrate this point, we show that an S20R/G24P/I26P
triple mutant and an H18R/I26P double mutant are nonamyloidogenic
and significantly more soluble than human IAPP or PM. These analogues
and second-generation derivatives are potential candidates for the
coformulation
of IAPP with insulin and other polypeptides.
Collapse
Affiliation(s)
- Hui Wang
- Department of Chemistry, State University of New York at Stony Brook , Stony Brook, New York 11794-3400, United States
| | | | | | | |
Collapse
|
29
|
Lednev IK. Amyloid fibrils: the eighth wonder of the world in protein folding and aggregation. Biophys J 2014; 106:1433-5. [PMID: 24703304 DOI: 10.1016/j.bpj.2014.02.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 01/31/2014] [Accepted: 02/04/2014] [Indexed: 10/25/2022] Open
Affiliation(s)
- Igor K Lednev
- Department of Chemistry, University at Albany, State University of New York, Albany, New York.
| |
Collapse
|