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Miller ME, Li MH, Baghai A, Peetz VH, Zhyvoloup A, Raleigh DP. Analysis of Sheep and Goat IAPP Provides Insight into IAPP Amyloidogenicity and Cytotoxicity. Biochemistry 2022; 61:2531-2545. [PMID: 36286531 PMCID: PMC11132794 DOI: 10.1021/acs.biochem.2c00470] [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] [Indexed: 11/29/2022]
Abstract
Human islet amyloid polypeptide (hIAPP) plays a role in glucose regulation but forms pancreatic amyloid deposits in type 2 diabetes, and that process contributes to β-cell dysfunction. Not all species develop diabetes, and not all secrete an IAPP that is amyloidogenic in vitro under normal conditions, a perfect correlation currently exists between both. Studies of IAPPs from such organisms can provide clues about the high amyloidogenicity of hIAPP and can inform the design of soluble analogues of hIAPP. Sheep and goat IAPP are among the most divergent from hIAPP, with 13 and 11 substitutions, respectively, including an unusual Tyr to His substitution at the C-terminus. The properties of sheep and goat IAPP were examined in solution and in the presence of anionic vesicles, resulting in no observed amyloid formation, even at increased concentrations. Furthermore, both peptides are considerably less toxic to cultured β-cells than hIAPP. The effect of the Y37H replacements was studied in the context of hIAPP, as was a Y37R substitution. Buffer- and salt-dependent effects were observed. There was little impact on the time to form amyloid in phosphate-buffered saline; however, a significant deceleration was observed in Tris buffer, and amyloid formation was slower in the absence of added salt. The Y37H substitution had little impact on toxicity, while the Y37R replacement led to a 30% decrease in toxicity compared with that of hIAPP. The implications for the amyloidogenicity of hIAPP and the design of soluble analogues of the human peptide are discussed.
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Affiliation(s)
- Matthew E.T. Miller
- Department of Chemistry, Stony Brook University, Nicolls Road, Stony Brook, New York 11790, United States
| | - Ming-Hao Li
- Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, New York 11790, United States
| | - Aria Baghai
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Vincent H. Peetz
- Department of Chemistry, Stony Brook University, Nicolls Road, Stony Brook, New York 11790, United States
| | - Alexander Zhyvoloup
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Daniel P. Raleigh
- Department of Chemistry, Stony Brook University, Nicolls Road, Stony Brook, New York 11790, United States
- Graduate Program in Biochemistry and Structural Biology, Stony Brook University, Stony Brook, New York 11790, United States
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York 11794, United States
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2
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Reselammal DS, Pinhero F, Sharma R, Oliyantakath Hassan MS, Srinivasula SM, Vijayan V. Mapping the Fibril Core of the Prion Subdomain of the Mammalian CPEB3 that is Involved in Long Term Memory Retention. J Mol Biol 2021; 433:167084. [PMID: 34081983 DOI: 10.1016/j.jmb.2021.167084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 11/15/2022]
Abstract
Long-term memory storage is modulated by the prion nature of CPEB3 forming the molecular basis for the maintenance of synaptic facilitation. Here we report that the first prion sub-domain PRD1 of mouse CPEB3 can autonomously form amyloid fibrils in vitro and punctate-like structures in vivo. A ninety-four amino acid sequence within the PRD1 domain, PRD1-core, displays high propensity towards aggregation and associated amyloid characteristics. PRD1-core is characterized using electron microscopy, X-ray diffraction, and solution-state NMR deuterium exchange experiments. Secondary structure elements deduced from solid-state NMR reveal a β-rich core comprising of forty amino acids at the N-terminus of PRD1-core. The synthesized twenty-three amino acid long peptide containing the longest rigid segment (E124-H145) of the PRD1-core rapidly self-aggregates and forms fibrils, indicating a limited aggregation-prone region that could potentially activate the aggregation of the full-length protein. This study provides the first step in identifying the structural trigger for the CPEB3 aggregation process.
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Affiliation(s)
- Dhanya S Reselammal
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum 695551, India
| | - Faina Pinhero
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum 695551, India
| | - Rahul Sharma
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum 695551, India
| | | | - Srinivasa M Srinivasula
- School of Biology, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum 695551, India
| | - Vinesh Vijayan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Trivandrum 695551, India.
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3
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Söldner CA, Sticht H, Horn AH. Molecular Simulations and Alzheimer׳s Disease. SYSTEMS MEDICINE 2021. [DOI: 10.1016/b978-0-12-801238-3.11541-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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4
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Pandey P, Nguyen N, Hansmann UHE. d-Retro Inverso Amylin and the Stability of Amylin Fibrils. J Chem Theory Comput 2020; 16:5358-5368. [PMID: 32667784 DOI: 10.1021/acs.jctc.0c00523] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Motivated by the role that amylin aggregates play in type-II diabetes, we compare the stability of regular amylin fibrils with the stability of fibrils where l-amino acid chains are replaced by d-retro inverso (DRI) amylin, that is, peptides where the sequence of amino acids is reversed, and at the same time, the l-amino acids are replaced by their mirror images. Our molecular dynamics simulations show that despite leading to only a marginal difference in the fibril structure and stability, aggregating DRI-amylin peptides have different patterns of contacts and hydrogen bonding. Because of these differences, DRI-amylin, when interacting with regular (l) amylin, alters the elongation process and lowers the stability of hybrid amylin fibrils. Our results not only suggest the potential use of DRI-amylin as an inhibitor of amylin fibril formation but also point to the possibility of using the insertion of DRI proteins in l-assemblies as a way to probe the role of certain kinds of hydrogen bonds in supramolecular assemblies or aggregates.
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Affiliation(s)
- Preeti Pandey
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Natalie Nguyen
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Ulrich H E Hansmann
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
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5
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Zhou J, Ruggeri FS, Zimmermann MR, Meisl G, Longo G, Sekatskii SK, Knowles TPJ, Dietler G. Effects of sedimentation, microgravity, hydrodynamic mixing and air-water interface on α-synuclein amyloid formation. Chem Sci 2020; 11:3687-3693. [PMID: 34094057 PMCID: PMC8152616 DOI: 10.1039/d0sc00281j] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/06/2020] [Indexed: 12/28/2022] Open
Abstract
The formation of amyloid fibrils is a characterizing feature of a range of protein misfolding diseases, including Parkinson's disease. The propensity of native proteins to form such amyloid fibril, both in vitro and in vivo, is highly sensitive to the surrounding environment, which can alter the aggregation kinetics and fibrillization mechanisms. Here, we investigate systematically the influence of several representative environmental stimuli on α-synuclein aggregation, including hydrodynamic mixing, the presence of an air-water interface and sedimentation. Our results show that hydrodynamic mixing and interfacial effects are critical in promoting several microscopic steps of α-synuclein aggregation and amyloid fibril formation. The presence of an air-water interface under agitation significantly promoted primary nucleation. Secondary processes were facilitated by hydrodynamic mixing, produced by 3D rotation and shaking either in the presence or in the absence of an air-water interface. Effects of sedimentation, as investigated in a microgravity incubator, of α-synuclein lead only to minor changes on the aggregation kinetics rates in comparison to static conditions. These results forward the understanding of α-synuclein fibrillization, paving the way for the development of high-throughput assays for the screening of pharmacological approaches targeting Parkinson's disease.
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Affiliation(s)
- Jiangtao Zhou
- Laboratory of Physics of Living Matter, École Polytechnique Fédérale de Lausanne (EPFL) CH-1015 Lausanne Switzerland
| | - Francesco S Ruggeri
- Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Manuela R Zimmermann
- Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Georg Meisl
- Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Giovanni Longo
- Istituto di Struttura della Materia, CNR Via del Fosso del Cavaliere 100 Roma 00133 Italy
| | - Sergey K Sekatskii
- Laboratory of Physics of Living Matter, École Polytechnique Fédérale de Lausanne (EPFL) CH-1015 Lausanne Switzerland
| | - Tuomas P J Knowles
- Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Giovanni Dietler
- Laboratory of Physics of Living Matter, École Polytechnique Fédérale de Lausanne (EPFL) CH-1015 Lausanne Switzerland
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6
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Xi W, Vanderford EK, Liao Q, Hansmann UHE. Stability of Aβ-fibril fragments in the presence of fatty acids. Protein Sci 2019; 28:1973-1981. [PMID: 31461191 DOI: 10.1002/pro.3719] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/10/2019] [Accepted: 08/22/2019] [Indexed: 11/07/2022]
Abstract
We consider the effect of lauric acid on the stability of various fibril-like assemblies of Aβ peptides. For this purpose, we have performed molecular dynamics simulations of these assemblies either in complex with lauric acid or without presence of the ligand. While we do not observe a stabilizing effect on Aβ40 -fibrils, we find that addition of lauric acid strengthens the stability of fibrils built from the triple-stranded S-shaped Aβ42 -peptides considered to be more toxic. Or results may help to understand how the specifics of the brain-environment modulate amyloid formation and propagation.
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Affiliation(s)
- Wenhui Xi
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma
| | - Elliott K Vanderford
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma
| | - Qinxin Liao
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Ulrich H E Hansmann
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma
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Moore SJ, Sonar K, Bharadwaj P, Deplazes E, Mancera RL. Characterisation of the Structure and Oligomerisation of Islet Amyloid Polypeptides (IAPP): A Review of Molecular Dynamics Simulation Studies. Molecules 2018; 23:E2142. [PMID: 30149632 PMCID: PMC6225196 DOI: 10.3390/molecules23092142] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 08/21/2018] [Accepted: 08/22/2018] [Indexed: 12/26/2022] Open
Abstract
Human islet amyloid polypeptide (hIAPP) is a naturally occurring, intrinsically disordered protein whose abnormal aggregation into amyloid fibrils is a pathological feature in type 2 diabetes, and its cross-aggregation with amyloid beta has been linked to an increased risk of Alzheimer's disease. The soluble, oligomeric forms of hIAPP are the most toxic to β-cells in the pancreas. However, the structure of these oligomeric forms is difficult to characterise because of their intrinsic disorder and their tendency to rapidly aggregate into insoluble fibrils. Experimental studies of hIAPP have generally used non-physiological conditions to prevent aggregation, and they have been unable to describe its soluble monomeric and oligomeric structure at physiological conditions. Molecular dynamics (MD) simulations offer an alternative for the detailed characterisation of the monomeric structure of hIAPP and its aggregation in aqueous solution. This paper reviews the knowledge that has been gained by the use of MD simulations, and its relationship to experimental data for both hIAPP and rat IAPP. In particular, the influence of the choice of force field and water models, the choice of initial structure, and the configurational sampling method used, are discussed in detail. Characterisation of the solution structure of hIAPP and its mechanism of oligomerisation is important to understanding its cellular toxicity and its role in disease states, and may ultimately offer new opportunities for therapeutic interventions.
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Affiliation(s)
- Sandra J Moore
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute and Curtin Institute for Computation, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
| | - Krushna Sonar
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute and Curtin Institute for Computation, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
| | - Prashant Bharadwaj
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute and Curtin Institute for Computation, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
- Centre of Excellence for Alzheimer's Disease Research and Care, School of Medical and Health Sciences, 270 Joondalup Drive, Edith Cowan University, Joondalup, WA 6027, Australia.
| | - Evelyne Deplazes
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute and Curtin Institute for Computation, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
| | - Ricardo L Mancera
- School of Pharmacy and Biomedical Sciences, Curtin Health Innovation Research Institute and Curtin Institute for Computation, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
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8
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Carbamylation promotes amyloidogenesis and induces structural changes in Tau-core hexapeptide fibrils. Biochim Biophys Acta Gen Subj 2018; 1862:2590-2604. [PMID: 30071272 DOI: 10.1016/j.bbagen.2018.07.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/10/2018] [Accepted: 07/26/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Carbamylation is a non-enzymatic post-translational modification (PTM), which involves the covalent modification of N-terminus of protein or ε-amino group of Lys. The role of carbamylation in several age-related disorders is well documented, however, the relationship between carbamylation and neurodegenerative disorders including Alzheimer's disease remains uncharted. METHODS In the present study, using aggregation-prone tau-core hexapeptide fragments 306VQIVYK311 (PHF6) and 275VQIINK280 (PHF6*) as models, we have elucidated the effect of carbamylation on aggregation kinetics and the changes occurring in the 3-dimensional architecture of fibrils using biophysical assays and molecular dynamics simulations. RESULTS We found that carbamylation aids in amyloid formation and can convert the unstructured off-pathway aggregates into robust amyloids, which were toxic to cells. Electron microscopy images and molecular dynamics simulations of PHF6 fibrils showed that carbamylated peptides can form excess hydrogen bonds and modulate the pitch length and twist of peptides fibrils. We have also compared N-terminal carbamylation to acetylation and further extended our finding to full length tau that exhibits aggregation upon carbamylation even in the absence of any external inducer. CONCLUSION Our in vitro and in silico results together suggest that carbamylation can modulate the aggregation pathway of the amyloidegenic sequences and cause structural changes in fibril assemblies. GENERAL SIGNIFICANCE Carbamylation acts as a switch, which triggers the aggregation in short amyloidogenic peptide fragments and modulate the structural changes in resulting amyloid fibrils.
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9
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Baram M, Gilead S, Gazit E, Miller Y. Mechanistic perspective and functional activity of insulin in amylin aggregation. Chem Sci 2018; 9:4244-4252. [PMID: 29780554 PMCID: PMC5944211 DOI: 10.1039/c8sc00481a] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/14/2018] [Indexed: 11/21/2022] Open
Abstract
This work provides the first-ever complete atomic model of insulin–amylin aggregates, identifying the specific interactions that stabilize the insulin–amylin complex.
Insulin is a key regulatory polypeptide that is secreted from pancreatic β-cells and has several important effects on the synthesis of lipids, regulation of enzymatic activities, blood glucose levels and the prevention of hyperglycemia. Insulin was demonstrated to self-assemble into ordered amyloid fibrils upon repeated injections, although the possible biological significance of the supramolecular structures is enigmatic. Amylin is also an amyloidogenic polypeptide that is secreted from pancreatic β-cells and plays an important role in glycemic regulation preventing post-prandial spikes in blood glucose levels. These two amyloidogenic proteins are secreted together from the pancreas and have the ability to interact and produce insulin–amylin aggregates. So far, the molecular architecture of insulin–amylin complexes at the atomic resolution has been unknown. The current work identifies for the first time the specific π–π interactions between Y16 in insulin and F19 in amylin that contribute to the stability of the insulin–amylin complex, by using experimental and molecular modeling techniques. We performed additional experiments that verify the functional activity of insulin in amylin aggregation. Our findings illustrate for the first time the specific interactions between insulin and amylin aggregates at the atomic resolution and provide a new mechanistic perspective on the effect of insulin on amylin aggregation and may pave the way towards pharmacological intervention in this process.
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Affiliation(s)
- Michal Baram
- Department of Chemistry , Ben-Gurion University of the Negev , Be'er Sheva 84105 , Israel . .,The Ilse Katz Institute for Nanoscale Science & Technology , Ben-Gurion University of the Negev , Be'er Sheva 84105 , Israel
| | - Sharon Gilead
- Department of Molecular Microbiology and Biotechnology , Tel Aviv University , Tel Aviv 69978 , Israel .
| | - Ehud Gazit
- Department of Molecular Microbiology and Biotechnology , Tel Aviv University , Tel Aviv 69978 , Israel . .,Department of Materials Science and Engineering , Iby and Aladar Fleischman Faculty of Engineering , Tel Aviv University , Tel Aviv 69978 , Israel
| | - Yifat Miller
- Department of Chemistry , Ben-Gurion University of the Negev , Be'er Sheva 84105 , Israel . .,The Ilse Katz Institute for Nanoscale Science & Technology , Ben-Gurion University of the Negev , Be'er Sheva 84105 , Israel
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10
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Liu Y, Ren B, Zhang Y, Sun Y, Chang Y, Liang G, Xu L, Zheng J. Molecular simulation aspects of amyloid peptides at membrane interface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1906-1916. [PMID: 29421626 DOI: 10.1016/j.bbamem.2018.02.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 12/13/2022]
Abstract
The interactions of amyloid peptides with cell membranes play an important role in maintaining the integrity and functionality of cell membrane. A thorough molecular-level understanding of the structure, dynamics, and interactions between amyloid peptides and cell membranes is critical to amyloid aggregation and toxicity mechanisms for the bench-to-bedside applications. Here we review the most recent computational studies of amyloid peptides at model cell membranes. Different mechanisms of action of amyloid peptides on/in cell membranes, targeted by different computational techniques at different lengthscales and timescales, are rationally discussed. Finally, we have proposed some new insights into the remaining challenges and perspectives for future studies to improve our understanding of the activity of amyloid peptides associated with protein-misfolding diseases. This article is part of a Special Issue entitled: Protein Aggregation and Misfolding at the Cell Membrane Interface edited by Ayyalusamy Ramamoorthy.
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Affiliation(s)
- Yonglan Liu
- Hunan Key Laboratory of Biomedical Nanomaterials and Devices, College of Life Science and Chemistry, Hunan University of Technology, Zhuzhou 412007, PR China; Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States
| | - Baiping Ren
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States
| | - Yanxian Zhang
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States
| | - Yan Sun
- Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Yung Chang
- R&D Center for Membrane Technology and Department of Chemical EngineeringChung Yuan Christian University, Chung-Li, Taoyuan 320, Taiwan
| | - Guizhao Liang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044, PR China
| | - Lijian Xu
- Hunan Key Laboratory of Biomedical Nanomaterials and Devices, College of Life Science and Chemistry, Hunan University of Technology, Zhuzhou 412007, PR China; Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States.
| | - Jie Zheng
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, United States.
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11
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Folmert K, Broncel M, V Berlepsch H, Ullrich CH, Siegert MA, Koksch B. Inhibition of peptide aggregation by means of enzymatic phosphorylation. Beilstein J Org Chem 2017; 12:2462-2470. [PMID: 28144314 PMCID: PMC5238555 DOI: 10.3762/bjoc.12.240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 11/03/2016] [Indexed: 11/30/2022] Open
Abstract
As is the case in numerous natural processes, enzymatic phosphorylation can be used in the laboratory to influence the conformational populations of proteins. In nature, this information is used for signal transduction or energy transfer, but has also been shown to play an important role in many diseases like tauopathies or diabetes. With the goal of determining the effect of phosphorylation on amyloid fibril formation, we designed a model peptide which combines structural characteristics of α-helical coiled-coils and β-sheets in one sequence. This peptide undergoes a conformational transition from soluble structures into insoluble amyloid fibrils over time and under physiological conditions and contains a recognition motif for PKA (cAMP-dependent protein kinase) that enables enzymatic phosphorylation. We have analyzed the pathway of amyloid formation and the influence of enzymatic phosphorylation on the different states along the conformational transition from random-coil to β-sheet-rich oligomers to protofilaments and on to insoluble amyloid fibrils, and we found a remarkable directing effect from β-sheet-rich structures to unfolded structures in the initial growth phase, in which small oligomers and protofilaments prevail if the peptide is phosphorylated.
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Affiliation(s)
- Kristin Folmert
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | | | - Hans V Berlepsch
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
| | | | - Mary-Ann Siegert
- Department of Organic Chemistry, Technische Universität Berlin, Strasse des 17. Juni 124, 10623 Berlin, Germany
| | - Beate Koksch
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany
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12
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Lee M, Chang HJ, Baek I, Na S. Structural analysis of oligomeric and protofibrillar Aβ amyloid pair structures considering F20L mutation effects using molecular dynamics simulations. Proteins 2016; 85:580-592. [PMID: 28019690 DOI: 10.1002/prot.25232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 11/12/2016] [Accepted: 11/23/2016] [Indexed: 12/20/2022]
Abstract
Aβ amyloid proteins are involved in neuro-degenerative diseases such as Alzheimer's, Parkinson's, and so forth. Because of its structurally stable feature under physiological conditions, Aβ amyloid protein disrupts the normal cell function. Because of these concerns, understanding the structural feature of Aβ amyloid protein in detail is crucial. There have been some efforts on lowering the structural stabilities of Aβ amyloid fibrils by decreasing the aromatic residues characteristic and hydrophobic effect. Yet, there is a lack of understanding of Aβ amyloid pair structures considering those effects. In this study, we provide the structural characteristics of wildtype (WT) and phenylalanine residue mutation to leucine (F20L) Aβ amyloid pair structures using molecular dynamics simulation in detail. We also considered the polymorphic feature of F20L and WT Aβ pair amyloids based on the facing β-strand directions between the amyloid pairs. As a result, we were able to observe the varying effects of mutation, polymorphism, and protofibril lengths on the structural stability of pair amyloids. Furthermore, we have also found that opposite structural stability exists on a certain polymorphic Aβ pair amyloids depending on its oligomeric or protofibrillar state, which can be helpful for understanding the amyloid growth mechanism via repetitive fragmentation and elongation mechanism. Proteins 2017; 85:580-592. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Myeongsang Lee
- Department of Mechanical Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Hyun Joon Chang
- Department of Mechanical Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Inchul Baek
- Department of Mechanical Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Sungsoo Na
- Department of Mechanical Engineering, Korea University, Seoul, 02841, Republic of Korea
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13
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Zhang M, Ren B, Chen H, Sun Y, Ma J, Jiang B, Zheng J. Molecular Simulations of Amyloid Structures, Toxicity, and Inhibition. Isr J Chem 2016. [DOI: 10.1002/ijch.201600075] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Mingzhen Zhang
- Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325 USA
| | - Baiping Ren
- Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325 USA
| | - Hong Chen
- Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325 USA
| | - Yan Sun
- Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology Tianjin University Tianjin 300072 P. R. China
| | - Jie Ma
- Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325 USA
- State Key Laboratory of Pollution Control and Resource Reuse School of Environmental Science and Engineering Tongji University Shanghai 200092 P. R. China
| | - Binbo Jiang
- Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325 USA
- College of Chemical and Biological Engineering Zhejiang University Hangzhou Zhejiang 310027 P. R. China
| | - Jie Zheng
- Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325 USA
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14
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Economou NJ, Giammona MJ, Do TD, Zheng X, Teplow DB, Buratto SK, Bowers MT. Amyloid β-Protein Assembly and Alzheimer's Disease: Dodecamers of Aβ42, but Not of Aβ40, Seed Fibril Formation. J Am Chem Soc 2016; 138:1772-5. [PMID: 26839237 DOI: 10.1021/jacs.5b11913] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Evidence suggests that oligomers of the 42-residue form of the amyloid β-protein (Aβ), Aβ42, play a critical role in the etiology of Alzheimer's disease (AD). Here we use high resolution atomic force microscopy to directly image populations of small oligomers of Aβ42 that occur at the earliest stages of aggregation. We observe features that can be attributed to a monomer and to relatively small oligomers, including dimers, hexamers, and dodecamers. We discovered that Aβ42 hexamers and dodecamers quickly become the dominant oligomers after peptide solubilization, even at low (1 μM) concentrations and short (5 min) incubation times. Soon after (≥10 min), dodecamers are observed to seed the formation of extended, linear preprotofibrillar β-sheet structures. The preprotofibrils are a single Aβ42 layer in height and can extend several hundred nanometers in length. To our knowledge this is the first report of structures of this type. In each instance the preprotofibril is associated off center with a single layer of a dodecamer. Protofibril formation continues at longer times, but is accompanied by the formation of large, globular aggregates. Aβ40, by contrast, does not significantly form the hexamer or dodecamer but instead produces a mixture of smaller oligomers. These species lead to the formation of a branched chain-like network rather than discrete structures.
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Affiliation(s)
- Nicholas J Economou
- Department of Chemistry and Biochemistry, University of California , Santa Barbara, California 93106, United States
| | - Maxwell J Giammona
- Department of Chemistry and Biochemistry, University of California , Santa Barbara, California 93106, United States
| | - Thanh D Do
- Department of Chemistry and Biochemistry, University of California , Santa Barbara, California 93106, United States
| | - Xueyun Zheng
- Department of Chemistry and Biochemistry, University of California , Santa Barbara, California 93106, United States
| | - David B Teplow
- Department of Neurology, David Geffen School of Medicine at UCLA; Mary S. Easton Center for Alzheimer's Disease Research at UCLA; and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
| | - Steven K Buratto
- Department of Chemistry and Biochemistry, University of California , Santa Barbara, California 93106, United States
| | - Michael T Bowers
- Department of Chemistry and Biochemistry, University of California , Santa Barbara, California 93106, United States
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15
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Jeong HR, An SSA. Causative factors for formation of toxic islet amyloid polypeptide oligomer in type 2 diabetes mellitus. Clin Interv Aging 2015; 10:1873-9. [PMID: 26604727 PMCID: PMC4655906 DOI: 10.2147/cia.s95297] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Human islet amyloid polypeptide (h-IAPP) is a peptide hormone that is synthesized and cosecreted with insulin from insulin-secreting pancreatic β-cells. Recently, h-IAPP was proposed to be the main component responsible for the cytotoxic pancreatic amyloid deposits in patients with type 2 diabetes mellitus (T2DM). Since the causative factors of IAPP (or amylin) oligomer aggregation are not fully understood, this review will discuss the various forms of h-IAPP aggregation. Not all forms of IAPP aggregates trigger the destruction of β-cell function and loss of β-cell mass; however, toxic oligomers do trigger these events. Once these toxic oligomers form under abnormal metabolic conditions in T2DM, they can lead to cell disruption by inducing cell membrane destabilization. In this review, the various factors that have been shown to induce toxic IAPP oligomer formation will be presented, as well as the potential mechanism of oligomer and fibril formation from pro-IAPPs. Initially, pro-IAPPs undergo enzymatic reactions to produce the IAPP monomers, which can then develop into oligomers and fibrils. By this mechanism, toxic oligomers could be generated by diverse pathway components. Thus, the interconnections between factors that influence amyloid aggregation (eg, absence of PC2 enzyme, deamidation, reduction of disulfide bonds, environmental factors in the cell, genetic mutations, copper metal ions, and heparin) will be presented. Hence, this review will aid in understanding the fundamental causative factors contributing to IAPP oligomer formation and support studies for investigating novel T2DM therapeutic approaches, such as the development of inhibitory agents for preventing oligomerization at the early stages of diabetic pathology.
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Affiliation(s)
- Hye Rin Jeong
- Department of Bionano Technology, Gachon Medical Research Institute, Gachon University, Gyeonggi-do, Republic of Korea
| | - Seong Soo A An
- Department of Bionano Technology, Gachon Medical Research Institute, Gachon University, Gyeonggi-do, Republic of Korea
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16
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Zhang M, Hu R, Chen H, Chang Y, Ma J, Liang G, Mi J, Wang Y, Zheng J. Polymorphic cross-seeding amyloid assemblies of amyloid-β and human islet amyloid polypeptide. Phys Chem Chem Phys 2015; 17:23245-56. [PMID: 26283068 DOI: 10.1039/c5cp03329b] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Epidemiological studies have shown that the development of Alzheimer's disease (AD) is associated with type 2 diabetes (T2D), but it still remains unclear how AD and T2D are connected. Heterologous cross-seeding between the causative peptides of Aβ and hIAPP may represent a molecular link between AD and T2D. Here, we computationally modeled and simulated a series of cross-seeding double-layer assemblies formed by Aβ and hIAPP peptides using all-atom and coarse-gained molecular dynamics (MD) simulations. The cross-seeding Aβ-hIAPP assemblies showed a wide range of polymorphic structures via a combination of four β-sheet-to-β-sheet interfaces and two packing orientations, focusing on a comparison of different matches of β-sheet layers. Two cross-seeding Aβ-hIAPP assemblies with different interfacial β-sheet packings exhibited high structural stability and favorable interfacial interactions in both oligomeric and fibrillar states. Both Aβ-hIAPP assemblies displayed interfacial dehydration to different extents, which in turn promoted Aβ-hIAPP association depending on interfacial polarity and geometry. Furthermore, computational mutagenesis studies revealed that disruption of interfacial salt bridges largely disfavor the β-sheet-to-β-sheet association, highlighting the importance of salt bridges in the formation of cross-seeding assemblies. This work provides atomic-level information on the cross-seeding interactions between Aβ and hIAPP, which may be involved in the interplay between these two disorders.
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Affiliation(s)
- Mingzhen Zhang
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, USA.
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17
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Zhang M, Hu R, Chen H, Gong X, Zhou F, Zhang L, Zheng J. Polymorphic Associations and Structures of the Cross-Seeding of Aβ1–42 and hIAPP1–37 Polypeptides. J Chem Inf Model 2015; 55:1628-39. [DOI: 10.1021/acs.jcim.5b00166] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
| | | | | | | | - Feimeng Zhou
- Department
of Chemistry and Biochemistry, California State University, Los Angeles, Los Angeles, California 90032, United States
| | - Li Zhang
- Department
of Geriatric Neurology, Nanjing Brain Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu 210029, China
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18
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Alred EJ, Scheele EG, Berhanu WM, Hansmann UHE. Stability of Iowa mutant and wild type Aβ-peptide aggregates. J Chem Phys 2015; 141:175101. [PMID: 25381547 DOI: 10.1063/1.4900892] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Recent experiments indicate a connection between the structure of amyloid aggregates and their cytotoxicity as related to neurodegenerative diseases. Of particular interest is the Iowa Mutant, which causes early-onset of Alzheimer's disease. While wild-type Amyloid β-peptides form only parallel beta-sheet aggregates, the mutant also forms meta-stable antiparallel beta sheets. Since these structural variations may cause the difference in the pathological effects of the two Aβ-peptides, we have studied in silico the relative stability of the wild type and Iowa mutant in both parallel and antiparallel forms. We compare regular molecular dynamics simulations with such where the viscosity of the samples is reduced, which, we show, leads to higher sampling efficiency. By analyzing and comparing these four sets of all-atom molecular dynamics simulations, we probe the role of the various factors that could lead to the structural differences. Our analysis indicates that the parallel forms of both wild type and Iowa mutant aggregates are stable, while the antiparallel aggregates are meta-stable for the Iowa mutant and not stable for the wild type. The differences result from the direct alignment of hydrophobic interactions in the in-register parallel oligomers, making them more stable than the antiparallel aggregates. The slightly higher thermodynamic stability of the Iowa mutant fibril-like oligomers in its parallel organization over that in antiparallel form is supported by previous experimental measurements showing slow inter-conversion of antiparallel aggregates into parallel ones. Knowledge of the mechanism that selects between parallel and antiparallel conformations and determines their relative stability may open new avenues for the development of therapies targeting familial forms of early-onset Alzheimer's disease.
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Affiliation(s)
- Erik J Alred
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Emily G Scheele
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Workalemahu M Berhanu
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Ulrich H E Hansmann
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA
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19
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Alred EJ, Phillips M, Berhanu WM, Hansmann UHE. On the lack of polymorphism in Aβ-peptide aggregates derived from patient brains. Protein Sci 2015; 24:923-35. [PMID: 25739352 DOI: 10.1002/pro.2668] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 02/11/2015] [Accepted: 02/15/2015] [Indexed: 11/09/2022]
Abstract
The amyloid beta (Aβ) oligomers and fibrils that are found in neural tissues of patients suffering from Alzheimer's disease may either cause or contribute to the pathology of the disease. In vitro, these Aβ-aggregates are characterized by structural polymorphism. However, recent solid state NMR data of fibrils acquired post mortem from the brains of two Alzheimer's patients indicate presence of only a single, patient-specific structure. Using enhanced molecular dynamic simulations we investigate the factors that modulate the stability of Aβ-fibrils. We find characteristic differences in molecular flexibility, dynamics of interactions, and structural behavior between the brain-derived Aβ-fibril structure and in vitro models. These differences may help to explain the lack of polymorphism in fibrils collected from patient brains, and have to be taken into account when designing aggregation inhibitors and imaging agents for Alzheimer's disease.
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Affiliation(s)
- Erik J Alred
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma, 73019
| | - Malachi Phillips
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma, 73019
| | - Workalemahu M Berhanu
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma, 73019
| | - Ulrich H E Hansmann
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma, 73019
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20
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21
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Zhang M, Hu R, Chen H, Chang Y, Gong X, Liu F, Zheng J. Interfacial interaction and lateral association of cross-seeding assemblies between hIAPP and rIAPP oligomers. Phys Chem Chem Phys 2015; 17:10373-82. [DOI: 10.1039/c4cp05658b] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cross-sequence interactions between different amyloid peptides are important not only for fundamental understanding of amyloid aggregation and polymorphism mechanisms, but also for probing a potential molecular link between different amyloid diseases.
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Affiliation(s)
- Mingzhen Zhang
- Department of Chemical and Biomolecular Engineering
- The University of Akron
- Akron
- USA
| | - Rundong Hu
- Department of Chemical and Biomolecular Engineering
- The University of Akron
- Akron
- USA
| | - Hong Chen
- Department of Chemical and Biomolecular Engineering
- The University of Akron
- Akron
- USA
| | - Yung Chang
- R&D Center for Membrane Technology and Department of Chemical Engineering
- Chung Yuan University
- Taoyuan 320
- Taiwan
| | - Xiong Gong
- College of Polymer Science and Polymer Engineering
- The University of Akron
- Akron
- USA
| | - Fufeng Liu
- Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering (Ministry of Education)
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
- China
| | - Jie Zheng
- Department of Chemical and Biomolecular Engineering
- The University of Akron
- Akron
- USA
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22
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Tomasello MF, Sinopoli A, Pappalardo G. On the Environmental Factors Affecting the Structural and Cytotoxic Properties of IAPP Peptides. J Diabetes Res 2015; 2015:918573. [PMID: 26582441 PMCID: PMC4637107 DOI: 10.1155/2015/918573] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/05/2015] [Indexed: 12/18/2022] Open
Abstract
Pancreatic islets in type 2 diabetes mellitus (T2DM) patients are characterized by reduced β-cells mass and diffuse extracellular amyloidosis. Amyloid deposition involves the islet amyloid polypeptide (IAPP), a neuropancreatic hormone cosecreted with insulin by β-cells. IAPP is physiologically involved in glucose homeostasis, but it may turn toxic to β-cells owing to its tendency to misfold giving rise to oligomers and fibrils. The process by which the unfolded IAPP starts to self-assemble and the overall factors promoting this conversion are poorly understood. Other open questions are related to the nature of the IAPP toxic species and how exactly β-cells die. Over the last decades, there has been growing consensus about the notion that early molecular assemblies, notably small hIAPP oligomers, are the culprit of β-cells decline. Numerous environmental factors might affect the conformational, aggregation, and cytotoxic properties of IAPP. Herein we review recent progress in the field, focusing on the influences that membranes, pH, and metal ions may have on the conformational conversion and cytotoxicity of full-length IAPP as well as peptide fragments thereof. Current theories proposed for the mechanisms of toxicity will be also summarized together with an outline of the underlying molecular links between IAPP and amyloid beta (Aβ) misfolding.
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Affiliation(s)
| | - Alessandro Sinopoli
- International PhD Program in Translational Biomedicine, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Giuseppe Pappalardo
- CNR Institute of Biostructures and Bioimaging, Via P. Gaifami 18, 95126 Catania, Italy
- *Giuseppe Pappalardo:
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23
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Wineman-Fisher V, Atsmon-Raz Y, Miller Y. Orientations of residues along the β-arch of self-assembled amylin fibril-like structures lead to polymorphism. Biomacromolecules 2014; 16:156-65. [PMID: 25420121 DOI: 10.1021/bm501326y] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Amylin is an endocrine hormone peptide that consists of 37 residues and is the main component of extracellular amyloid deposits found in the pancreas of most type 2 diabetes patients. Amylin peptides are self-assembled to form oligomers and fibrils. So far, four different molecular structures of the self-assembled amylin fibrils have been observed experimentally: two ssNMR models and two crystal models. This study reveals, for the first time, that there are four self-assembled amylin forms that differ in the orientations of the side chains along the β-arch and are all derived from the two ssNMR models. The two ssNMR models are composed of these four different self-assembled forms of amylin, and the two crystal models are composed of two different self-assembled forms of amylin. This study illustrates at the atomic level the differences among the four experimental models and proposes eight new models of self-assembled amylin that are also composed of the four different self-assembled forms of amylin. Our results show polymorphism of the self-assembled fibril-like amylin, with a slight preference of some of the newly constructed models over the experimental models. Finally, we propose that two different self-assembled fibril-like forms of amylin can interact to form a new fibril-like amylin. We investigated this argument and found that some fibril-like amylin prefers to interact to form stable fibril-like structures, whereas others disfavor it. Our work provides new insights that may suggest strategies for future pharmacological studies that aim to find ways to ameliorate the interactions between polymorphic oligomers and fibrils of amylin.
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Affiliation(s)
- Vered Wineman-Fisher
- Department of Chemistry and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer-Sheva 84105, Israel
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24
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Batzli KM, Love BJ. Agitation of amyloid proteins to speed aggregation measured by ThT fluorescence: a call for standardization. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 48:359-64. [PMID: 25579934 DOI: 10.1016/j.msec.2014.09.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/11/2014] [Indexed: 10/24/2022]
Abstract
This retrospective study of protein aggregation measured by Thioflavin T (ThT) fluorescence assay in published literature has assessed protein sensitivity to denaturing conditions that include elevated temperatures, fluctuations in pH, and concentration and, in particular, agitation to induce amyloid structure formation. The dynamic tracking of fluorescence shows a sigmoidal evolution as aggregates form; the resulting kinetics of association have been analyzed to explore the range of aggregation behavior which occurs based on environmental parameters. Comparisons between the experimental results of different groups have been historically difficult due to subtleties of experimental procedures including denaturing temperature, protein type and concentration, formulation differences, and how agitation is achieved. While it is clear that agitation has a strong influence on the driving force for aggregation, the use of magnetic stirring bar or shaker table rotational speed is insufficient to characterize the degree of turbulence produced during shear. The pathway forward in resolving dependence of aggregate formation on shear may require alternative methodologies or better standardization of the experimental protocols.
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Affiliation(s)
- Kiersten M Batzli
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Brian J Love
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Macromolecular Science and Engineering Research Center, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering and Biologic and Materials Sciences (Dentistry), University of Michigan, Ann Arbor, MI 48109, USA.
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25
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Berhanu WM, Hansmann UHE. Stability of amyloid oligomers. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2014; 96:113-41. [PMID: 25443956 DOI: 10.1016/bs.apcsb.2014.06.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Molecular simulations are now commonly used to complement experimental techniques in investigating amyloids and their role in human diseases. In this chapter, we will summarize techniques and approaches often used in amyloid simulations and will present recent success stories. Our examples will be focused on lessons learned from molecular dynamics simulations in aqueous environments that start from preformed aggregates. These studies explore the limitations that arise from the choice of force field, the role of mutations in the growth of amyloid aggregates, segmental polymorphism, and the importance of cross-seeding. Furthermore, they give evidence for potential toxicity mechanisms. We finally discuss the role of molecular simulations in the search for aggregation inhibitors.
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Affiliation(s)
- Workalemahu M Berhanu
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| | - Ulrich H E Hansmann
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, Oklahoma, USA.
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26
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Zhang M, Hu R, Liang G, Chang Y, Sun Y, Peng Z, Zheng J. Structural and Energetic Insight into the Cross-Seeding Amyloid Assemblies of Human IAPP and Rat IAPP. J Phys Chem B 2014; 118:7026-36. [DOI: 10.1021/jp5022246] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Mingzhen Zhang
- Department
of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Rundong Hu
- Department
of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Guizhao Liang
- Key
Laboratory of Biorheological Science and Technology, Ministry of Education,
Bioengineering College, Chongqing University, Chongqing 400044, China
| | - Yung Chang
- R&D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan University, Chung Li, Taoyuan 320, Taiwan
| | - Yan Sun
- Department
of Biochemical Engineering and Key Laboratory of Systems Bioengineering
of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Collaborative
Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
| | - Zhenmeng Peng
- Department
of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Jie Zheng
- Department
of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
- Collaborative
Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
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27
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Morriss-Andrews A, Shea JE. Simulations of Protein Aggregation: Insights from Atomistic and Coarse-Grained Models. J Phys Chem Lett 2014; 5:1899-908. [PMID: 26273871 DOI: 10.1021/jz5006847] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
This Perspective highlights recent computational approaches to protein aggregation, from coarse-grained models to atomistic simulations, using the islet amyloid polypeptide (IAPP) as a case study. We review salient open questions where simulations can make an impact, discuss the successes and challenges met by simulations, and explore new directions.
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Affiliation(s)
- Alex Morriss-Andrews
- Department of Chemistry and Biochemistry and Department of Physics, University of California, Santa Barbara, California 93106-9510, United States
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry and Department of Physics, University of California, Santa Barbara, California 93106-9510, United States
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28
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Berhanu WM, Hansmann UHE. Inter-species cross-seeding: stability and assembly of rat-human amylin aggregates. PLoS One 2014; 9:e97051. [PMID: 24810618 PMCID: PMC4014569 DOI: 10.1371/journal.pone.0097051] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 03/28/2014] [Indexed: 12/14/2022] Open
Abstract
Diseases such as type 2 diabetes, Alzheimer's and Parkinson's share as common feature the accumulation of mis-folded disease-specific protein aggregates into fibrillar structures, or plaques. These fibrils may either be toxic by themselves, or act as reservoirs for smaller cytotoxic oligomers. This suggests to investigate molecules as potential therapeutics that either reduce fibril formation or increase fibril stability. One example is rat amylin, which can inhibit aggregation of human amylin, a hallmark of type 2 diabetes. In the present paper, we use molecular dynamics to compare the stability of various preformed aggregates, built out of either human amylin, rat amylin, or mixtures of both. We considered two types of fibril-like oligomers: a single-layer in-register conformation, and a double-layer conformation in which the first U-shaped layer consists of rat amylin and the second layer of human amylin. Our results explain the weak amyloid-inhibiting properties of rat amylin and suggest that membrane leakage due to pore formation is responsible for the toxicity of rat amylin observed in a recent experiment. Together, our results put in question the use of rat amylin or the similar FDA approved drug pramlintide as an inhibitor of human amylin aggregation. They also point to mixed human-rat amylin fibril-like oligomers as possible model-systems for studies of amyloid formation that involve cross-species transmission.
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Affiliation(s)
- Workalemahu M. Berhanu
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, United States of America
| | - Ulrich H. E. Hansmann
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, United States of America
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