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He L, Wang X, Zhu D, Zhao C, Du W. Methionine oxidation of amyloid peptides by peroxovanadium complexes: inhibition of fibril formation through a distinct mechanism. Metallomics 2015; 7:1562-72. [DOI: 10.1039/c5mt00133a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Peroxovanadium complexes inhibit the fibril formation of neurodegenerative amyloid peptides by oxidizing methionine residues.
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Affiliation(s)
- Lei He
- Department of Chemistry
- Renmin University of China
- Beijing, China
| | - Xuesong Wang
- Department of Chemistry
- Renmin University of China
- Beijing, China
| | - Dengsen Zhu
- Department of Chemistry
- Renmin University of China
- Beijing, China
| | - Cong Zhao
- Department of Chemistry
- Renmin University of China
- Beijing, China
| | - Weihong Du
- Department of Chemistry
- Renmin University of China
- Beijing, China
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52
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Zhang Y, Yin F, Liu J, Wang Y. Geniposide protects pancreatic INS-1E β cells from hIAPP-induced cell damage: Potential involvement of insulin degrading-enzyme. Cell Biol Int 2014; 39:373-8. [DOI: 10.1002/cbin.10394] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 09/19/2014] [Indexed: 12/19/2022]
Affiliation(s)
- Yonglan Zhang
- College of Pharmacy and Bioengineering; Chongqing University of Technology; Chongqing 400054 China
- Chongqing Key Lab of Catalysis and Functional Organic Molecules; Chongqing Technology and Business University; Chongqing 400067 China
- College of Chemistry and Chemical Engineering; Chongqing University; Chongqing 400030 China
| | - Fei Yin
- College of Pharmacy and Bioengineering; Chongqing University of Technology; Chongqing 400054 China
- Chongqing Key Lab of Catalysis and Functional Organic Molecules; Chongqing Technology and Business University; Chongqing 400067 China
| | - Jianhui Liu
- College of Pharmacy and Bioengineering; Chongqing University of Technology; Chongqing 400054 China
- Chongqing Key Lab of Catalysis and Functional Organic Molecules; Chongqing Technology and Business University; Chongqing 400067 China
| | - Yanwen Wang
- Aquatic and Crop Resource Development; National Research Council of Canada; 5500 University Avenue; Charlottetown PE C1A 4P3 Canada
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53
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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
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Hebda JA, Magzoub M, Miranker AD. Small molecule screening in context: lipid-catalyzed amyloid formation. Protein Sci 2014; 23:1341-8. [PMID: 25043951 DOI: 10.1002/pro.2518] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 07/03/2014] [Accepted: 07/10/2014] [Indexed: 12/20/2022]
Abstract
Islet Amyloid Polypeptide (IAPP) is a 37-residue hormone cosecreted with insulin by the β-cells of the pancreas. Amyloid fiber aggregation of IAPP has been correlated with the dysfunction and death of these cells in type II diabetics. The likely mechanisms by which IAPP gains toxic function include energy independent cell membrane penetration and induction of membrane depolarization. These processes have been correlated with solution biophysical observations of lipid bilayer catalyzed acceleration of amyloid formation. Although the relationship between amyloid formation and toxicity is poorly understood, the fact that conditions promoting one also favor the other suggests related membrane active structural states. Here, a novel high throughput screening protocol is described that capitalizes on this correlation to identify compounds that target membrane active species. Applied to a small library of 960 known bioactive compounds, we are able to report identification of 37 compounds of which 36 were not previously reported as active toward IAPP fiber formation. Several compounds tested in secondary cell viability assays also demonstrate cytoprotective effects. It is a general observation that peptide induced toxicity in several amyloid diseases (such as Alzhiemer's and Parkinson's) involves a membrane bound, preamyloid oligomeric species. Our data here suggest that a screening protocol based on lipid-catalyzed assembly will find mechanistically informative small molecule hits in this subclass of amyloid diseases.
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Affiliation(s)
- James A Hebda
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, 06520-8114
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55
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Hu R, Zhang M, Patel K, Wang Q, Chang Y, Gong X, Zhang G, Zheng J. Cross-sequence interactions between human and rat islet amyloid polypeptides. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:5193-5201. [PMID: 24754490 DOI: 10.1021/la500632d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Human islet amyloid polypeptide (hIAPP) can assemble into toxic oligomers and fibrils, which are associated with cell degeneration and the pathogenesis of type 2 diabetes. Cross-interaction of hIAPP with rat IAPP (rIAPP)--a non-amyloidogenic peptide with high sequence similarity to hIAPP--might influence the aggregation and toxicity of hIAPP. However, the exact role of rIAPP in hIAPP aggregation and toxicity still remains unclear. In this work, we investigated the effect of cross-sequence interactions between full-length hIAPP(1-37) and rIAPP(1-37) on hybrid amyloid structures, aggregation kinetics, and cell toxicity using combined computational and experimental approaches. Experimental results indicate a contrasting role of rIAPP in hIAPP aggregation, in which rIAPP initially inhibits the early aggregation and nuclei formation of hIAPP, but hIAPP seeds can also recruit both hIAPP and rIAPP to form more hybrid fibrils, thus promoting amyloid fibrillation ultimately. The coincubation of hIAPP and rIAPP also decreases cell viability, presumably due to the formation of more toxic hybrid oligomers at the prolonged lag phase. Comparative MD simulations confirm that the cross-sequence interactions between hIAPP and rIAPP stabilize β-sheet structure and thus likely promote their fibrillization. This work provides valuable insights into a critical role of cross-amyloid interactions in protein aggregation.
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Affiliation(s)
- Rundong Hu
- Department of Chemical and Biomolecular Engineering, The University of Akron , Akron, Ohio 44325, United States
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56
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A hIAPP-derived all-d-amino-acid inhibits hIAPP fibrillation efficiently at membrane surface by targeting α-helical oligomeric intermediates. FEBS Lett 2014; 588:884-91. [DOI: 10.1016/j.febslet.2014.02.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 02/05/2014] [Accepted: 02/05/2014] [Indexed: 11/20/2022]
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57
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Abstract
Amylin is a peptide that aggregates into species that are toxic to pancreatic beta cells, leading to type II diabetes. This study has for the first time quantified amylin association and dissociation kinetics (association constant (ka ) = 28.7 ± 5.1 L mol-1 s-1 and dissociation constant (kd ) = 2.8 ± 0.6 ×10-4 s-1) using surface plasmon resonance (SPR). Thus far, techniques used for the sizing of amylin aggregates do not cater for the real-time monitoring of unconstrained amylin in solution. In this regard we evaluated recently innovated nanoparticle tracking analysis (NTA). In addition, both SPR and NTA were used to study the effect of previously synthesized amylin derivatives on amylin aggregation and to evaluate their potential as a cell-free system for screening potential inhibitors of amylin-mediated cytotoxicity. Results obtained from NTA highlighted a predominance of 100-300 nm amylin aggregates and correlation to previously published cytotoxicity results suggests the toxic species of amylin to be 200-300 nm in size. The results seem to indicate that NTA has potential as a new technique to monitor the aggregation potential of amyloid peptides in solution and also to screen potential inhibitors of amylin-mediated cytotoxicity.
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Affiliation(s)
- Karen Pillay
- Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Patrick Govender
- Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
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58
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He L, Wang X, Zhao C, Zhu D, Du W. Inhibition of human amylin fibril formation by insulin-mimetic vanadium complexes. Metallomics 2014; 6:1087-96. [DOI: 10.1039/c4mt00021h] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Inhibition of human amylin fibril formation by insulin-mimetic vanadium complexes.
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Affiliation(s)
- Lei He
- Department of Chemistry
- Renmin University of China
- Beijing, China
| | - Xuesong Wang
- Department of Chemistry
- Renmin University of China
- Beijing, China
| | - Cong Zhao
- Department of Chemistry
- Renmin University of China
- Beijing, China
| | - Dengsen Zhu
- Department of Chemistry
- Renmin University of China
- Beijing, China
| | - Weihong Du
- Department of Chemistry
- Renmin University of China
- Beijing, China
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59
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Structural similarities and differences between amyloidogenic and non-amyloidogenic islet amyloid polypeptide (IAPP) sequences and implications for the dual physiological and pathological activities of these peptides. PLoS Comput Biol 2013; 9:e1003211. [PMID: 24009497 PMCID: PMC3757079 DOI: 10.1371/journal.pcbi.1003211] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 07/20/2013] [Indexed: 12/22/2022] Open
Abstract
IAPP, a 37 amino-acid peptide hormone belonging to the calcitonin family, is an intrinsically disordered protein that is coexpressed and cosecreted along with insulin by pancreatic islet β-cells in response to meals. IAPP plays a physiological role in glucose regulation; however, in certain species, IAPP can aggregate and this process is linked to β-cell death and Type II Diabetes. Using replica exchange molecular dynamics with extensive sampling (16 replicas per sequence and 600 ns per replica), we investigate the structure of the monomeric state of two species of aggregating peptides (human and cat IAPP) and two species of non-aggregating peptides (pig and rat IAPP). Our simulations reveal that the pig and rat conformations are very similar, and consist of helix-coil and helix-hairpin conformations. The aggregating sequences, on the other hand, populate the same helix-coil and helix-hairpin conformations as the non-aggregating sequence, but, in addition, populate a hairpin structure. Our exhaustive simulations, coupled with available peptide-activity data, leads us to a structure-activity relationship (SAR) in which we propose that the functional role of IAPP is carried out by the helix-coil conformation, a structure common to both aggregating and non-aggregating species. The pathological role of this peptide may have multiple origins, including the interaction of the helical elements with membranes. Nonetheless, our simulations suggest that the hairpin structure, only observed in the aggregating species, might be linked to the pathological role of this peptide, either as a direct precursor to amyloid fibrils, or as part of a cylindrin type of toxic oligomer. We further propose that the helix-hairpin fold is also a possible aggregation prone conformation that would lead normally non-aggregating variants of IAPP to form fibrils under conditions where an external perturbation is applied. The SAR relationship is used to suggest the rational design of therapeutics for treating diabetes. IAPP, a 37 amino-acid peptide hormone belonging to the calcitonin family, is an intrinsically disordered peptide produced along with insulin by pancreatic islet β-cells in response to meals. In its functional form, IAPP acts as a synergic partner of insulin to reduce blood glucose. IAPP can, however, also play a pathological role, contributing to Type II diabetes (T2D). Knowledge of the structural nature of the physiological and pathological forms of IAPP will facilitate the rational design of novel drugs for therapeutic treatment of T2D. However, because IAPP does not fold to a single structure, but rather co-exists between multiple functional (and toxic) structures, it is extremely challenging for experimental methods to gain detailed structural information. Using a computational approach, we were able to obtain detailed structures of four IAPP variants and propose a novel structural hypothesis for the two opposing roles of this peptide.
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60
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Mishra A, Misra A, Vaishnavi TS, Thota C, Gupta M, Ramakumar S, Chauhan VS. Conformationally restricted short peptides inhibit human islet amyloid polypeptide (hIAPP) fibrillization. Chem Commun (Camb) 2013; 49:2688-90. [PMID: 23435449 PMCID: PMC3684849 DOI: 10.1039/c3cc38982k] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Inhibition of human islet amyloid polypeptide (hIAPP) fibrillisation by peptides incorporating a helicogenic amino acid, dehydrophenylalanine: implications for Type-2 diabetes.
hIAPP fibrillization implicated in Type 2 diabetes pathology involves formation of oligomers toxic to insulin producing pancreatic β-cells. We report design, synthesis, 3D structure and functional characterization of dehydrophenylalanine (ΔF) containing peptides which inhibit hIAPP fibrillization. The inhibitor protects β-cells from hIAPP induced toxicity.
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Affiliation(s)
- Aseem Mishra
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
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61
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Pillay K, Govender P. A direct fluorescence-based technique for cellular localization of amylin. Biotechnol Appl Biochem 2013; 60:384-92. [DOI: 10.1002/bab.1113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 03/11/2013] [Indexed: 01/03/2023]
Affiliation(s)
- Karen Pillay
- School of Life Sciences; University of KwaZulu-Natal; South Africa
| | - Patrick Govender
- School of Life Sciences; University of KwaZulu-Natal; South Africa
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62
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Yan LM, Velkova A, Tatarek-Nossol M, Rammes G, Sibaev A, Andreetto E, Kracklauer M, Bakou M, Malideli E, Göke B, Schirra J, Storr M, Kapurniotu A. Selektiv N-methylierte lösliche IAPP-Mimetika als potente IAPP-Rezeptoragonisten und nanomolare Inhibitoren der Selbstassoziation von IAPP und Aβ40. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201302840] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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63
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Yan LM, Velkova A, Tatarek-Nossol M, Rammes G, Sibaev A, Andreetto E, Kracklauer M, Bakou M, Malideli E, Göke B, Schirra J, Storr M, Kapurniotu A. Selectively N-methylated soluble IAPP mimics as potent IAPP receptor agonists and nanomolar inhibitors of cytotoxic self-assembly of both IAPP and Aβ40. Angew Chem Int Ed Engl 2013; 52:10378-83. [PMID: 23956012 DOI: 10.1002/anie.201302840] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 06/08/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Li-Mei Yan
- Division of Peptide Biochemistry, Technische Universität München, Emil-Erlenmeyer-Forum 5, 85354 Freising (Germany) http://pbch.wzw.tum.de/
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64
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Zhang M, Mao X, Yu Y, Wang CX, Yang YL, Wang C. Nanomaterials for reducing amyloid cytotoxicity. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:3780-801. [PMID: 23722464 DOI: 10.1002/adma.201301210] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Indexed: 05/20/2023]
Abstract
This review is intended to reflect the recent progress on therapeutic applications of nanomaterials in amyloid diseases. The progress on anti-amyloid functions of various nanomaterials including inorganic nanoparticles, polymeric nanoparticles, carbon nanomaterials and biomolecular aggregates, is reviewed and discussed. The main functionalization strategies for general nanoparticle modifications are reviewed for potential applications of targeted therapeutics. The interaction mechanisms between amyloid peptides and nanomaterials are discussed from the perspectives of dominant interactions and kinetics. The encapsulation of anti-amyloid drugs, targeted drug delivery, controlled drug release and drug delivery crossing blood brain barrier by application of nanomaterials would also improve the therapeutics of amyloid diseases.
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Affiliation(s)
- Min Zhang
- National Center for Nanoscience and Technology, Beijing 100190, China
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65
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Amylin uncovered: a review on the polypeptide responsible for type II diabetes. BIOMED RESEARCH INTERNATIONAL 2013; 2013:826706. [PMID: 23607096 PMCID: PMC3626316 DOI: 10.1155/2013/826706] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 02/21/2013] [Indexed: 11/17/2022]
Abstract
Amylin is primarily responsible for classifying type II diabetes as an amyloid (protein misfolding) disease as it has great potential to aggregate into toxic nanoparticles, thereby resulting in loss of pancreatic β-cells. Although type II diabetes is on the increase each year, possibly due to bad eating habits of modern society, research on the culprit for this disease is still in its early days. In addition, unlike the culprit for Alzheimer's disease, amyloid β-peptide, amylin has failed to receive attention worthy of being featured in an abundance of review articles. Thus, the aim of this paper is to shine the spotlight on amylin in an attempt to put it onto the top of researchers' to-do list since the secondary complications of type II diabetes have far-reaching and severe consequences on public health both in developing and fully developed countries alike. This paper will cover characteristics of the amylin aggregates, mechanisms of toxicity, and a particular focus on inhibitors of toxicity and techniques used to assess these inhibitors.
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66
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He L, Wang X, Zhao C, Wang H, Du W. Ruthenium complexes as novel inhibitors of human islet amyloid polypeptide fibril formation. Metallomics 2013; 5:1599-603. [DOI: 10.1039/c3mt00146f] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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67
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Chatterjee J, Rechenmacher F, Kessler H. N-methylation of peptides and proteins: an important element for modulating biological functions. Angew Chem Int Ed Engl 2012; 52:254-69. [PMID: 23161799 DOI: 10.1002/anie.201205674] [Citation(s) in RCA: 330] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Indexed: 11/06/2022]
Abstract
N-Methylation is one of the simplest chemical modifications often occurring in peptides and proteins of prokaryotes and higher eukaryotes. Over years of evolution, nature has employed N-methylation of peptides as an ingenious technique to modulate biological function, often as a mode of survival through the production of antibiotics. This small structural change can not only mobilize large protein complexes (as in the histone methylation), but also inhibits the action of enzymes by selective recognition of protein-protein interaction surfaces. In recent years through the advancement in synthetic approaches, the potential of N-methylation has begun to be revealed, not only in modulating biological activity and selectivity as well as pharmacokinetic properties of peptides, but also in delivering novel drugs. Herein, we summarize the current knowledge of the versatility of N-methylation in modulating biological, structural, and pharmacokinetic properties of peptides.
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Affiliation(s)
- Jayanta Chatterjee
- Genome biology unit, European Molecular Biology Laboratory, Heidelberg, Germany
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68
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Chatterjee J, Rechenmacher F, Kessler H. N-Methylierung von Peptiden und Proteinen: ein wichtiges Element für die Regulation biologischer Funktionen. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201205674] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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69
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Andreasen M, Nielsen SB, Mittag T, Bjerring M, Nielsen JT, Zhang S, Nielsen EH, Jeppesen M, Christiansen G, Besenbacher F, Dong M, Nielsen NC, Skrydstrup T, Otzen DE. Modulation of fibrillation of hIAPP core fragments by chemical modification of the peptide backbone. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:274-85. [DOI: 10.1016/j.bbapap.2011.10.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 10/14/2011] [Accepted: 10/24/2011] [Indexed: 11/30/2022]
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70
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Doran TM, Kamens AJ, Byrnes NK, Nilsson BL. Role of amino acid hydrophobicity, aromaticity, and molecular volume on IAPP(20-29) amyloid self-assembly. Proteins 2012; 80:1053-65. [DOI: 10.1002/prot.24007] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 11/12/2011] [Accepted: 11/18/2011] [Indexed: 01/22/2023]
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71
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Srinivasan A. Experimental inhibition of peptide fibrillogenesis by synthetic peptides, carbohydrates and drugs. Subcell Biochem 2012; 65:271-94. [PMID: 23225008 DOI: 10.1007/978-94-007-5416-4_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Peptide fibrillogenesis generally begins by the transformation of normally soluble proteins into elongated aggregates which are called as amyloid. These fibrils mainly consist of ß-sheets. They share certain common characteristics such as a cross-ß x-ray diffraction pattern, association with other common proteins and typical staining by the dye Congo Red. The individual form of the deposit consists of a disease-specific peptide/protein. The disease-specific protein serves as the basis for the classification of the amyloids. The association of fibril-forming peptides/proteins with diseases makes them primary disease-targets. Understanding the molecular interactions involved in the fibril formation becomes the foremost requirement to characterize the target. Interference with these interactions of ß-sheets in vitro prevents and sometimes reverses the fibril assembly. A small molecule capable of interfering with the formation of fibril could have therapeutic applications in these diseases. This anti-aggregation approach appears to be a viable treatment option. A search for such a molecule is pursued actively world over. All types of compounds and approaches to slow down or prevent the aggregation process have been described in the literature. These efforts are reviewed in this chapter.
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72
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Huggins KNL, Bisaglia M, Bubacco L, Tatarek-Nossol M, Kapurniotu A, Andersen NH. Designed hairpin peptides interfere with amyloidogenesis pathways: fibril formation and cytotoxicity inhibition, interception of the preamyloid state. Biochemistry 2011; 50:8202-12. [PMID: 21848289 DOI: 10.1021/bi200760h] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Hairpin peptides bearing cross-strand Trp-Trp and Tyr-Tyr pairs at non-H-bonded strand sites modulate the aggregation of two unrelated amyloidogenic systems, human pancreatic amylin (hAM) and α-synuclein (α-syn), associated with type II diabetes and Parkinson's disease, respectively. In the case of hAM, we have previously reported that inhibition of amyloidogenesis is observed as an increase in the lag time to amyloid formation and a diminished thioflavin (ThT) fluorescence response. In this study, a reduced level of hAM fibril formation is confirmed by transmission electron microscopy imaging. Several of the hairpins tested were significantly more effective inhibitors than rat amylin. Moreover, a marked inhibitory effect on hAM-associated cytotoxicity by the more potent hairpin peptide is demonstrated. In the case of α-syn, the dominant effect of active hairpins was, besides a weakened ThT fluorescence response, the earlier appearance of insoluble aggregates that do not display amyloid characteristics with the few fibrils observed having abnormal morphology. We attribute the alteration of the α-synuclein aggregation pathway observed to the capture of a preamyloid state and diversion to nonamyloidogenic aggregates. These β-hairpins represent a new class of amyloid inhibitors that bear no sequence similarity to the amyloid-producing polypeptides that are inhibited. A mechanistic rationale for these effects is proposed.
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Affiliation(s)
- Kelly N L Huggins
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
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73
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Andreetto E, Yan LM, Caporale A, Kapurniotu A. Dissecting the role of single regions of an IAPP mimic and IAPP in inhibition of Aβ40 amyloid formation and cytotoxicity. Chembiochem 2011; 12:1313-22. [PMID: 21630409 DOI: 10.1002/cbic.201100192] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Indexed: 01/11/2023]
Abstract
Alzheimer's disease (AD) and type 2 diabetes (T2D) are linked to the self-association of β-amyloid peptide (Aβ) and islet amyloid polypeptide (IAPP), respectively. We have shown that IAPP-GI, a soluble IAPP analogue and mimic of nonamyloidogenic and nontoxic IAPP, binds Aβ with high affinity and blocks its cytotoxic self-assembly and fibrillogenesis. We have also shown that IAPP and Aβ interact with each other into nonfibrillar and nontoxic heterocomplexes that suppress cytotoxic self-association by both polypeptides. The Aβ-IAPP interaction might thus be a molecular link between AD and T2D. We studied the role of individual IAPP-GI and IAPP regions in their inhibitory function on Aβ40 self-association and cytotoxicity. We found that the presence of the two hot-spot regions of the Aβ-IAPP interaction interface in IAPP(8-28) is not sufficient for inhibitory function and that, in addition to IAPP(8-28), the presence of the N-terminal region IAPP(1-7) is absolutely required. By contrast, the C-terminal region, IAPP(30-37), is not required although its presence together with IAPP(1-7) in IAPP-GI results in a marked enhancement of the inhibitory effect as compared to IAPP(1-28)-GI. We suggest that the inhibitory effect of IAPP-GI and IAPP on Aβ40 fibrillogenesis and cell toxicity is mediated primarily by interactions involving the hot regions of the Aβ-IAPP interaction interface and the N terminus of IAPP while a concerted and likely structure-stabilizing action of the N- and C-terminal IAPP regions potentiates this effect. These results identify important molecular determinants of the amyloid suppressing function of the Aβ40-IAPP interaction and could contribute to the design of novel inhibitors of Aβ40 aggregation and cell degeneration.
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Affiliation(s)
- Erika Andreetto
- Division of Peptide Biochemistry, Technische Universität München, Freising-Weihenstephan, Germany
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74
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Dupuis NF, Wu C, Shea JE, Bowers MT. The amyloid formation mechanism in human IAPP: dimers have β-strand monomer-monomer interfaces. J Am Chem Soc 2011; 133:7240-3. [PMID: 21517093 DOI: 10.1021/ja1081537] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Early oligomerization of human IAPP (hIAPP) is responsible for β-cell death in the pancreas and is increasingly considered a primary pathological process linked to Type II Diabetes (T2D). Yet, the assembly mechanism remains poorly understood, largely due to the inability of conventional techniques to probe distributions or detailed structures of early oligomeric species. Here, we describe the first experimental data on the isolated and unmodified dimers of human (hIAPP) and nonamyloidogenic rat IAPP (rIAPP). The experiments reveal that the human IAPP dimers are more extended than those formed by rat IAPP and likely descend from extended monomers. Independent all-atom molecular dynamics simulations show that rIAPP forms compact helix and coil rich dimers, whereas hIAPP forms β-strand rich dimers that are generally more extended. Also, the simulations reveal that the monomer-monomer interfaces of the hIAPP dimers are dominated by β-strands and that β-strands can recruit coil or helix structured regions during the dimerization process. Our β-rich interface contrasts with an N-terminal helix-to-helix interface proposed in the literature but is consistent with existing experimental data on the self-interaction pattern of hIAPP, mutation effects, and inhibition effects of the N-methylation in the mutation region.
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Affiliation(s)
- Nicholas F Dupuis
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, USA
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75
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Berhanu WM, Masunov AE. Molecular dynamic simulation of wild type and mutants of the polymorphic amyloid NNQNTF segments of elk prion: structural stability and thermodynamic of association. Biopolymers 2011; 95:573-90. [PMID: 21384336 DOI: 10.1002/bip.21611] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 02/02/2011] [Accepted: 02/05/2011] [Indexed: 02/04/2023]
Abstract
A hexapeptide with amino acid sequence NNQNTF from the elk prion protein forms amyloid fibrils. Here we use molecular dynamic simulations of the oligomers and their single point glycine mutants to study their stability. In an effort to probe the structural stability and association thermodynamic in a realistic environment, all wildtype of NNQNTF polymorphic forms with different size and their corresponding double layer 5 strands single point glycine mutants were subjected to a total of 500 ns of explicit-solvent molecular dynamics (MD) simulation. Our results show that the structural stability of the NNQNTF oligomers increases with increasing the number of β-strands for double layers. Our results also demonstrated that hydrophobic interaction is the principle driving force to stabilize the adjacent β-strands while the steric zipper is responsible for holding the neighboring β-sheet layers together. We used MM-PBSA approach free energy calculations to determine the role of nonpolar effects, electrostatics and entropy in binding. Nonpolar effects remained consistently more favorable in wild type and mutants reinforcing the importance of hydrophobic effects in protein-protein binding. While entropy systematically opposed binding in all cases, there was no observed trend in the entropy difference between wildtype and glycine mutant. Free energy decomposition shows residues situated at the interface were found to make favorable contributions to the peptide-peptide association. The study of the wild type and mutants in an explicit solvent may provide valuable insight for amyloid aggregation inhibitor design efforts.
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Affiliation(s)
- Workalemahu M Berhanu
- NanoScience Technology Center, Department of Chemistry, University of Central Florida, Orlando, FL 32826, USA
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76
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Hu J, Yu YP, Cui W, Fang CL, Wu WH, Zhao YF, Li YM. Cyclen-hybrid compound captures copper to protect INS-1 cells from islet amyloid polypeptide cytotoxicity by inhibiting and lysing effects. Chem Commun (Camb) 2010; 46:8023-5. [PMID: 20856987 DOI: 10.1039/c0cc02555k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Human islet amyloid polypeptide (hIAPP) deposit is the hallmark of type 2 diabetes pathology. Here, we report that apo-cyclen, attached to a specific hIAPP recognition motif (NYGAIL), captured copper ions and became proteolytically active. This cyclen-NYGAIL-copper complex was able to interfere with hIAPP aggregation and cleave hIAPP. These activities rescued INS-1 cells from hIAPP induced cytotoxicity.
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Affiliation(s)
- Jia Hu
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
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77
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Hernández D, Lindsay KB, Nielsen L, Mittag T, Bjerglund K, Friis S, Mose R, Skrydstrup T. Further studies toward the stereocontrolled synthesis of silicon-containing peptide mimics. J Org Chem 2010; 75:3283-93. [PMID: 20423092 DOI: 10.1021/jo100301n] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Further studies are reported on the utilization of the versatile reaction between chiral sulfinimines and alkyldiphenylsilyl lithium reagents with the goal of preparing a wide range of silanediol-based protease inhibitors. In particular, focus has been placed to demonstrate how a number of genetically encoded amino acid side chains such as serine, threonine, tyrosine, lysine, proline, arginine, aspartate and asparagine might be incorporated into the overall approach. Efforts to apply this synthetic methodology for accessing biologically relevant silanediol dipeptide mimics are also described. This includes the synthesis of a potential inhibitor of the human neutrophil elastase, as well as a diphenylsilane mimic of a hexapeptide fragment of the human islet amyloid polypeptide.
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Affiliation(s)
- Dácil Hernández
- Center for Insoluble Protein Structures, Department of Chemistry and Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
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78
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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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79
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In vitro ADMET and physicochemical investigations of poly-N-methylated peptides designed to inhibit Aβ aggregation. Bioorg Med Chem 2010; 18:5896-902. [DOI: 10.1016/j.bmc.2010.06.087] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 06/24/2010] [Accepted: 06/28/2010] [Indexed: 11/23/2022]
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80
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Sellin D, Yan LM, Kapurniotu A, Winter R. Suppression of IAPP fibrillation at anionic lipid membranes via IAPP-derived amyloid inhibitors and insulin. Biophys Chem 2010; 150:73-9. [DOI: 10.1016/j.bpc.2010.01.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 01/20/2010] [Accepted: 01/21/2010] [Indexed: 12/01/2022]
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81
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Brender JR, Hartman K, Nanga RPR, Popovych N, de la Salud Bea R, Vivekanandan S, Marsh ENG, Ramamoorthy A. Role of zinc in human islet amyloid polypeptide aggregation. J Am Chem Soc 2010; 132:8973-83. [PMID: 20536124 PMCID: PMC2904811 DOI: 10.1021/ja1007867] [Citation(s) in RCA: 190] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Human Islet Amyloid Polypeptide (hIAPP) is a highly amyloidogenic protein found in islet cells of patients with type II diabetes. Because hIAPP is highly toxic to beta-cells under certain conditions, it has been proposed that hIAPP is linked to the loss of beta-cells and insulin secretion in type II diabetics. One of the interesting questions surrounding this peptide is how the toxic and aggregation prone hIAPP peptide can be maintained in a safe state at the high concentrations that are found in the secretory granule where it is stored. We show here zinc, which is found at millimolar concentrations in the secretory granule, significantly inhibits hIAPP amyloid fibrillogenesis at concentrations similar to those found in the extracellular environment. Zinc has a dual effect on hIAPP fibrillogenesis: it increases the lag-time for fiber formation and decreases the rate of addition of hIAPP to existing fibers at lower concentrations, while having the opposite effect at higher concentrations. Experiments at an acidic pH which partially neutralizes the change in charge upon zinc binding show inhibition is largely due to an electrostatic effect at His18. High-resolution structures of hIAPP determined from NMR experiments confirm zinc binding to His18 and indicate zinc induces localized disruption of the secondary structure of IAPP in the vicinity of His18 of a putative helical intermediate of IAPP. The inhibition of the formation of aggregated and toxic forms of hIAPP by zinc provides a possible mechanism between the recent discovery of linkage between deleterious mutations in the SLC30A8 zinc transporter, which transports zinc into the secretory granule, and type II diabetes.
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Affiliation(s)
- Jeffrey R. Brender
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Kevin Hartman
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | | | - Natalya Popovych
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Roberto de la Salud Bea
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Subramanian Vivekanandan
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - E. Neil G. Marsh
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
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82
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Muthusamy K, Albericio F, Arvidsson PI, Govender P, Kruger HG, Maguire GEM, Govender T. Microwave assisted SPPS of amylin and its toxicity of the pure product to RIN-5F cells. Biopolymers 2010; 94:323-30. [PMID: 20069542 DOI: 10.1002/bip.21370] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The 37-amino acid polypeptide islet amyloid polypeptide (IAPP), or amylin, is found as amyloid aggregates in the islets of Langerhans in patients with type II diabetes. Herein, we report an efficient microwave assisted solid phase peptide synthesis of amylin (IAPP). The most efficient synthesis used double and triple couplings and 10 equiv. of amino acids. Double couplings were used for most amino acids, whereas triple couplings were utilized for amino acids in selected regions. The most effective method for formation of the disulfide bond in amylin was found to be iodine oxidation. The highest purity amylin was obtained when the crude peptide was purified with HPLC before formation of the disulfide bond. The cytotoxicity of the synthesized amylin product to RIN-5F cells was determined. The synthesized amylin exhibits an exponential increase of cytotoxicity at concentrations >35 microM. Transmission electron microscope studies of a sample of amylin shows that insoluble amyloid fibrils spontaneously formed when 45 microM solution of synthesized amylin was incubated in a suitable buffer for 6 h.
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Affiliation(s)
- Karen Muthusamy
- School of Biochemistry, University of KwaZulu Natal, South Africa
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83
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Design and study of peptide-based inhibitors of amylin cytotoxicity. Bioorg Med Chem Lett 2010; 20:1360-2. [DOI: 10.1016/j.bmcl.2010.01.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2009] [Revised: 12/25/2009] [Accepted: 01/04/2010] [Indexed: 11/22/2022]
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84
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Sciacca MFM, Pappalardo M, Attanasio F, Milardi D, La Rosa C, Grasso DM. Are fibrilgrowth and membrane damage linked processes? An experimental and computational study of IAPP12–18and IAPP21–27peptides. NEW J CHEM 2010. [DOI: 10.1039/b9nj00253g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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85
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Pathuri G, Agashe HB, Awasthi V, Gali H. Radiosynthesis and in vivoevaluation of a F-18-labeled pancreatic islet amyloid inhibitor. J Labelled Comp Radiopharm 2010. [DOI: 10.1002/jlcr.1748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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86
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Abstract
The aggregation of numerous peptides or proteins has been linked to the onset of disease, including Abeta (amyloid beta-peptide) in AD (Alzheimer's disease), asyn (alpha-synuclein) in Parkinson's disease and amylin in Type 2 diabetes. Diverse amyloidogenic proteins can often be cut down to an SRE (self-recognition element) of as few as five residues that retains the ability to aggregate. SREs can be used as a starting point for aggregation inhibitors. In particular, N-methylated SREs can bind to a target on one side, but have hydrogen-bonding blocked on their methylated face, interfering with further assembly. We applied this strategy to develop Abeta toxicity inhibitors. Our compounds, and a range of compounds from the literature, were compared under the same conditions, using biophysical and toxicity assays. Two N-methylated D-peptide inhibitors with unnatural side chains were the most effective and can reverse Abeta-induced inhibition of LTP (long-term potentiation) at concentrations as low as 10 nM. An SRE in asyn (VAQKTV) was identified using solid-state NMR. When VAQKTV was N-methylated, it was able to disrupt asyn aggregation. N-methylated derivatives of the SRE of amylin are also able to inhibit amylin aggregation.
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87
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Amyloid inhibitors enhance survival of cultured human islets. Biochim Biophys Acta Gen Subj 2009; 1790:566-74. [PMID: 19264107 DOI: 10.1016/j.bbagen.2009.02.013] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 02/17/2009] [Accepted: 02/20/2009] [Indexed: 12/22/2022]
Abstract
BACKGROUND Amyloid fibrils created by misfolding and aggregation of proteins are a major pathological feature in a variety of degenerative diseases. Therapeutic approaches including amyloid vaccines and anti-aggregation compounds in models of amyloidosis point to an important role for amyloid in disease pathogenesis. Amyloid deposits derived from the beta-cell peptide islet amyloid polypeptide (IAPP or amylin) are a characteristic of type 2 diabetes and may contribute to loss of beta-cells in this disease. METHODS We developed a cellular model of rapid amyloid deposition using cultured human islets and observed a correlation between fibril accumulation and beta-cell death. A series of overlapping peptides derived from IAPP was generated. RESULTS A potent inhibitor (ANFLVH) of human IAPP aggregation was identified. This inhibitory peptide prevented IAPP fibril formation in vitro and in human islet cultures leading to a striking increase in islet cell viability. CONCLUSIONS These findings indicate an important contribution of IAPP aggregation to beta-cell death in situ and point to therapeutic applications for inhibitors of IAPP aggregation in enhancing beta-cell survival. GENERAL SIGNIFICANCE Anti-amyloid compounds could potentially reduce the loss of beta-cell mass in type 2 diabetes and maintain healthy human islet cultures for beta-cell replacement therapies.
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88
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Zhou N, Chen Z, Zhang D, Li G. Electrochemical Assay of Human Islet Amyloid Polypeptide and Its Aggregation. SENSORS 2008; 8:5987-5995. [PMID: 27873853 PMCID: PMC3705543 DOI: 10.3390/s8095987] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 09/11/2008] [Accepted: 09/22/2008] [Indexed: 12/29/2022]
Abstract
Square wave voltammetry is used in this work to detect human islet amyloid polypeptide (hIAPP) by using the oxidized signal of the tyrosine residue in hIAPP. A detection limit of 1×10-6 M for hIAPP has been obtained. A kinetic study of the aggregation process has been carried out according to the relationship between the anodic peak current in the square wave voltammograms of hIAPP and the incubation period. The results show that the nucleation starts in the first hour of incubation and then, during the next two hours, aggregation may occur rapidly. hIAPP can therefore be monitored with a label-free electrochemical method with low detection limit and high sensitivity. This electrochemical method can be also utilized to study the kinetics of hIAPP aggregation, and it may be also employed to study the conformational changes of the polypeptide.
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Affiliation(s)
- Nandi Zhou
- Laboratory of Biosensing Technology, School of Life Science, Shanghai University, Shanghai 200444, P.R. China
- Department of Biochemistry and National Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, P.R. China
| | - Zhenyu Chen
- Laboratory of Biosensing Technology, School of Life Science, Shanghai University, Shanghai 200444, P.R. China
| | - Dongmei Zhang
- Department of Biochemistry and National Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, P.R. China
| | - Genxi Li
- Laboratory of Biosensing Technology, School of Life Science, Shanghai University, Shanghai 200444, P.R. China.
- Department of Biochemistry and National Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, P.R. China.
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89
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Camus MS, Dos Santos S, Chandravarkar A, Mandal B, Schmid AW, Tuchscherer G, Mutter M, Lashuel HA. Switch-Peptides: Design and Characterization of Controllable Super-Amyloid-Forming Host-Guest Peptides as Tools for Identifying Anti-Amyloid Agents. Chembiochem 2008; 9:2104-12. [DOI: 10.1002/cbic.200800245] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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90
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Lopes DHJ, Smirnovas V, Winter R. Islet amyloid polypeptide and high hydrostatic pressure: towards an understanding of the fibrillization process. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/121/11/112002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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91
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Tartaglia GG, Pawar AP, Campioni S, Dobson CM, Chiti F, Vendruscolo M. Prediction of Aggregation-Prone Regions in Structured Proteins. J Mol Biol 2008; 380:425-36. [DOI: 10.1016/j.jmb.2008.05.013] [Citation(s) in RCA: 378] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2008] [Revised: 05/02/2008] [Accepted: 05/08/2008] [Indexed: 11/17/2022]
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92
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Radovan D, Smirnovas V, Winter R. Effect of pressure on islet amyloid polypeptide aggregation: revealing the polymorphic nature of the fibrillation process. Biochemistry 2008; 47:6352-60. [PMID: 18498175 DOI: 10.1021/bi800503j] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Type II diabetes mellitus is a disease which is characterized by peripheral insulin resistance coupled with a progressive loss of insulin secretion that is associated with a decrease in pancreatic islet beta-cell mass and the deposition of amyloid in the extracellular matrix of beta-cells, which lead to islet cell death. The principal component of the islet amyloid is a pancreatic hormone called islet amyloid polypeptide (IAPP). High-pressure coupled with FT-IR spectroscopic and AFM studies were carried out to elucidate further information about the aggregation pathway as well as the aggregate structures of IAPP. To this end, a comparative fibrillation study of IAPP fragments was carried out as well. As high hydrostatic pressure (HHP) is acting to weaken or even prevent hydrophobic self-organization and electrostatic interactions, application of HHP has been used as a measure to reveal the importance of these interactions in the fibrillation process of IAPP and its fragments. IAPP preformed fibrils exhibit a strong polymorphism with heterogeneous structures, a large population of which are rather sensitive to high hydrostatic pressure, thus indicating a high percentage of ionic and hydrophobic interactions and loose packing of these species. Conversely, fragments 1-19 and 1-29 are resistant to pressure treatment, suggesting more densely packed aggregate structures with less void volume and strong cooperative hydrogen bonding. Furthermore, the FT-IR data indicate that fragment 1-29 has intermolecular beta-sheet conformational properties different from those of fragment 1-19, the latter exhibiting polymorphic behavior with more disordered structures and less strongly hydrogen bonded fibrillar assemblies. The data also suggest that hydrophobic interactions and/or less efficient packing of amino acids 30-37 region leads to the marked pressure sensitivity observed for full-length IAPP.
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Affiliation(s)
- Diana Radovan
- Department of Chemistry, Physical Chemistry I-Biophysical Chemistry, Dortmund University of Technology, D-44227 Dortmund, Germany
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93
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Zhang S, Liu H, Yu H, Cooper GJS. Fas-associated death receptor signaling evoked by human amylin in islet beta-cells. Diabetes 2008; 57:348-56. [PMID: 17977957 DOI: 10.2337/db07-0849] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Aggregation of human amylin (hA) into beta-sheet-containing oligomers is linked to islet beta-cell dysfunction and the pathogenesis of type 2 diabetes. Here, we investigated possible contributions of Fas-associated death-receptor signaling to the mechanism of hA-evoked beta-cell apoptosis. RESEARCH DESIGN AND METHODS We measured responses to hA in isolated mouse islets and two insulinoma cell lines, wherein we measured Fas/Fas ligand (FasL) and Fas-associated death domain (FADD) expression by quantitative RT-PCR, Western blotting, and immunofluorescence staining. We used two anti-Fas/FasL blocking antibodies and the Fas/FasL antagonist Kp7-6 to probe roles of Fas interactions in the regulation of apoptosis in hA-treated beta-cells and measured Kp7-6-mediated effects on beta-sheet formation and aggregation using circular dichroism and thioflavin-T binding. RESULTS hA treatment stimulated Fas and FADD expression in beta-cells. Both blocking antibodies suppressed hA-evoked apoptosis but did not modify its aggregation. Therefore, Fas receptor interactions played a critical role in induction of this pathway. Interestingly, hA-evoked beta-cell apoptosis was suppressed and rescued by Kp7-6, which also impaired hA beta-sheet formation. CONCLUSIONS This is the first report linking hA-evoked induction and activation of Fas and FADD to beta-cell apoptosis. We have identified a Fas/FasL antagonist, Kp7-6, as a potent inhibitor of hA aggregation and related beta-cell death. These results also support an interaction between hA and Fas on the surface of apoptotic beta-cells. Increased expression and activation of Fas in beta-cells could constitute a molecular event common to the pathogenesis of both type 1 and type 2 diabetes, although the mode of pathway activation may differ between these common forms of diabetes.
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Affiliation(s)
- Shaoping Zhang
- School of Biological Sciences, University of Auckland, Level 4, 3A Symonds St., Private Bag 92019, Auckland 1142, New Zealand
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94
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Wu C, Wang Z, Lei H, Zhang W, Duan Y. Dual binding modes of Congo red to amyloid protofibril surface observed in molecular dynamics simulations. J Am Chem Soc 2007; 129:1225-32. [PMID: 17263405 DOI: 10.1021/ja0662772] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Congo red has been used to identify amyloid fibrils in tissues for more than 80 years and is also a weak inhibitor to both amyloid-beta fibril formation and toxicity. However, the specificity of the binding and its inhibition mechanism remain unclear. Using all-atom molecular dynamics simulations with the explicit solvent model, we have identified and characterized two specific binding modes of Congo red molecules to a protofibril formed by an amyloidogenic fragment (GNNQQNY) of the yeast prion protein Sup35. The observation of dual-mode was consistent with the experimentally observed dual-mode binding to Abeta fibrils by a series of compounds similar to Congo red. In the primary mode, Congo red bound to a regular groove formed by the first three residues (GNN) of the beta-strands along the beta-sheet extension direction. Comparative simulations demonstrated that Thioflavin T also bound to the grooves on KLVFFAE protofibril surface. Because of the ubiquitous long grooves on the amyloid fibril surface, we propose that this binding interaction could be a general recognition mode of amyloid fibrils by Congo red, Thioflavin T, and other long flat molecules. In the secondary mode, Congo red bound parallel to the beta-strands on the edge or in the middle of a beta-sheet. The primary binding mode of Congo red and GNNQQNY protofibril was more stable than the secondary mode by -5.7 kcal/mol as estimated by the MM-GBSA method. Detailed analysis suggests that the hydrophobic interactions play important roles for burial of the hydrophobic part of the Congo red molecules. Two potential inhibition mechanisms of disrupting beta-sheet stacking were inferred from the primary mode, which could be exploited for the development of non-peptidic amyloid-specific inhibitors.
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Affiliation(s)
- Chun Wu
- UC Davis Genome Center and Department of Applied Science, University of California, Davis, California 95616, USA
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95
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Yan LM, Velkova A, Tatarek-Nossol M, Andreetto E, Kapurniotu A. Ein IAPP-Mimetikum blockiert die zytotoxische Aggregation von Aβ – die Kreuzunterdrückung der Amyloidtoxizität von Aβ und IAPP deutet auf einen molekularen Zusammenhang zwischen Alzheimer-Krankheit und Typ-II-Diabetes hin. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200604056] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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96
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Yan LM, Velkova A, Tatarek-Nossol M, Andreetto E, Kapurniotu A. IAPP Mimic Blocks Aβ Cytotoxic Self-Assembly: Cross-Suppression of Amyloid Toxicity of Aβ and IAPP Suggests a Molecular Link between Alzheimer's Disease and Type II Diabetes. Angew Chem Int Ed Engl 2007; 46:1246-52. [PMID: 17203498 DOI: 10.1002/anie.200604056] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Li-Mei Yan
- Laboratory of Bioorganic and Medicinal Chemistry, Institute of Biochemistry, University Hospital of the RWTH Aachen, Pauwelsstrasse 30, 52074 Aachen, Germany
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97
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Wu C, Lei H, Wang Z, Zhang W, Duan Y. Phenol red interacts with the protofibril-like oligomers of an amyloidogenic hexapeptide NFGAIL through both hydrophobic and aromatic contacts. Biophys J 2006; 91:3664-72. [PMID: 16935948 PMCID: PMC1630471 DOI: 10.1529/biophysj.106.081877] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Amyloid-associated diseases affect millions of people worldwide. Phenol red exhibits modest inhibition toward fibril formation of human Islet amyloid polypeptide (hIAPP) and its toxicity, which is associated with type II diabetes mellitus. However, the molecular level mechanisms of interactions remain elusive. The binding of phenol red molecules to the protofibrils of an amyloidogenic fragment (NFGAIL) of hIAPP has been investigated by molecular dynamics simulations with explicit solvent. The phenol red molecules were observed to bind primarily along either beta-sheet stacking or beta-strand directions. Through its three aromatic rings, the phenol red molecule preferentially interacted with the hydrophobic side chains of Phe, Leu, and Ile; and the polar sulfone and hydroxyl groups were mainly exposed in solvent. Thus, phenol red improves the solubility of the early protofibrils and represses further growth. Interestingly, there was no obvious preference toward the aromatic Phe residue in comparison to the hydrophobic Leu or Ile residues. The lack of binding along the hydrogen bond direction indicates that phenol red does not directly block the beta-sheet extension. Further free energy analysis suggested that a phenol red analog may potentially improve the binding affinity.
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Affiliation(s)
- Chun Wu
- Genome Center and Department of Applied Science, University of California, Davis, California 95616, USA
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98
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Yan LM, Tatarek-Nossol M, Velkova A, Kazantzis A, Kapurniotu A. Design of a mimic of nonamyloidogenic and bioactive human islet amyloid polypeptide (IAPP) as nanomolar affinity inhibitor of IAPP cytotoxic fibrillogenesis. Proc Natl Acad Sci U S A 2006; 103:2046-51. [PMID: 16467158 PMCID: PMC1413694 DOI: 10.1073/pnas.0507471103] [Citation(s) in RCA: 206] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2005] [Indexed: 12/12/2022] Open
Abstract
Protein aggregation into cytotoxic oligomers and fibrils in vivo is linked to cell degeneration and the pathogenesis of >25 uncurable diseases, whereas the high aggregation propensity and insolubility of several bioactive polypeptides and proteins in vitro prevent their therapeutic use. Aggregation of human islet amyloid polypeptide (IAPP) into pancreatic amyloid is strongly associated with the pathogenesis of type II diabetes. IAPP is a 37-residue polypeptide that acts as a neuroendocrine regulator of glucose homeostasis. However, IAPP misfolds and self-associates into cytotoxic aggregates and fibrils even at nanomolar concentrations. Because IAPP aggregation causes beta-cell death and prohibits therapeutic application of IAPP in diabetes, we pursued a minimalistic chemical design approach to generate a molecular mimic of a nonamyloidogenic and bioactive IAPP conformation that would still be able to associate with IAPP and thus inhibit its fibrillogenesis and cytotoxicity. We show that the double N-methylated full length IAPP analog [(N-Me)G24, (N-Me)I26]-IAPP (IAPP-GI) is a highly soluble, nonamyloidogenic, and noncytotoxic IAPP molecular mimic and an IAPP receptor agonist. Moreover, IAPP-GI binds IAPP with low nanomolar affinity and completely blocks IAPP cytotoxic self-assembly and fibrillogenesis with activity in the low nanomolar concentration range. Importantly, IAPP-GI dissociates cytotoxic IAPP oligomers and fibrils and is able to reverse their cytotoxicity. Bifunctional soluble IAPP mimics that combine bioactivity with the ability to block and reverse IAPP cytotoxic self-assembly are promising candidates for the treatment of diabetes. Moreover, our amyloid disease inhibitor design concept may be applicable to other protein aggregation diseases.
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Affiliation(s)
- Li-Mei Yan
- Laboratory of Bioorganic and Medicinal Chemistry, Institute of Biochemistry, University Hospital of the Rheinisch–Westfälische Technische Hochschule Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany
| | - Marianna Tatarek-Nossol
- Laboratory of Bioorganic and Medicinal Chemistry, Institute of Biochemistry, University Hospital of the Rheinisch–Westfälische Technische Hochschule Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany
| | - Aleksandra Velkova
- Laboratory of Bioorganic and Medicinal Chemistry, Institute of Biochemistry, University Hospital of the Rheinisch–Westfälische Technische Hochschule Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany
| | - Athanasios Kazantzis
- Laboratory of Bioorganic and Medicinal Chemistry, Institute of Biochemistry, University Hospital of the Rheinisch–Westfälische Technische Hochschule Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany
| | - Aphrodite Kapurniotu
- Laboratory of Bioorganic and Medicinal Chemistry, Institute of Biochemistry, University Hospital of the Rheinisch–Westfälische Technische Hochschule Aachen, Pauwelstrasse 30, D-52074 Aachen, Germany
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