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Bai C, Lin D, Mo Y, Lei J, Sun Y, Xie L, Yang X, Wei G. Influence of fullerenol on hIAPP aggregation: amyloid inhibition and mechanistic aspects. Phys Chem Chem Phys 2019; 21:4022-4031. [DOI: 10.1039/c8cp07501h] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
C60(OH)24inhibits hIAPP aggregation by suppressing the fibril-prone structure and destabilizes hIAPP protofibrils by binding to the amyloid core region.
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Affiliation(s)
- Cuiqin Bai
- Department of Physics
- State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Science (Ministry of Education)
- Fudan University
- Shanghai 200433
- People's Republic of China
| | - Dongdong Lin
- Department of Microelectronic Science and Engineering Science Faculty of Science
- Ningbo University
- Ningbo 315211
- P. R. China
| | - Yuxiang Mo
- College of Physical Science and Technology
- Guangxi Normal University
- 15 Yucai Road
- Guilin
- China
| | - Jiangtao Lei
- Department of Physics
- State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Science (Ministry of Education)
- Fudan University
- Shanghai 200433
- People's Republic of China
| | - Yunxiang Sun
- Department of Physics
- State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Science (Ministry of Education)
- Fudan University
- Shanghai 200433
- People's Republic of China
| | - Luogang Xie
- College of Physics and Electronic Engineering
- Zhengzhou University of Light Industry
- Zhengzhou 453002
- People's Republic of China
| | - Xinju Yang
- Department of Physics
- State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Science (Ministry of Education)
- Fudan University
- Shanghai 200433
- People's Republic of China
| | - Guanghong Wei
- Department of Physics
- State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Science (Ministry of Education)
- Fudan University
- Shanghai 200433
- People's Republic of China
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52
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Sun Y, Kakinen A, Xing Y, Pilkington EH, Davis TP, Ke PC, Ding F. Nucleation of β-rich oligomers and β-barrels in the early aggregation of human islet amyloid polypeptide. Biochim Biophys Acta Mol Basis Dis 2018; 1865:434-444. [PMID: 30502402 DOI: 10.1016/j.bbadis.2018.11.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 11/10/2018] [Accepted: 11/26/2018] [Indexed: 10/27/2022]
Abstract
The self-assembly of human islet amyloid polypeptide (hIAPP) into β-sheet rich amyloid aggregates is associated with pancreatic β-cell death in type 2 diabetes (T2D). Prior experimental studies of hIAPP aggregation reported the early accumulation of α-helical intermediates before the rapid conversion into β-sheet rich amyloid fibrils, as also corroborated by our experimental characterizations with transmission electron microscopy and Fourier transform infrared spectroscopy. Although increasing evidence suggests that small oligomers populating early hIAPP aggregation play crucial roles in cytotoxicity, structures of these oligomer intermediates and their conformational conversions remain unknown, hindering our understanding of T2D disease mechanism and therapeutic design targeting these early aggregation species. We further applied large-scale discrete molecule dynamics simulations to investigate the oligomerization of full-length hIAPP, employing multiple molecular systems of increasing number of peptides. We found that the oligomerization process was dynamic, involving frequent inter-oligomeric exchanges. On average, oligomers had more α-helices than β-sheets, consistent with ensemble-based experimental measurements. However, in ~4-6% independent simulations, β-rich oligomers expected as the fibrillization intermediates were observed, especially in the pentamer and hexamer simulations. These β-rich oligomers could adopt β-barrel conformations, recently postulated to be the toxic oligomer species but only observed computationally in the aggregates of short amyloid protein fragments. Free-energy analysis revealed high energies of these β-rich oligomers, supporting the nucleated conformational changes of oligomers in amyloid aggregation. β-barrel oligomers of full-length hIAPP with well-defined three-dimensional structures may play an important pathological role in T2D etiology and may be a therapeutic target for the disease.
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Affiliation(s)
- Yunxiang Sun
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, USA
| | - Aleksandr Kakinen
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Yanting Xing
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, USA
| | - Emily H Pilkington
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia; Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
| | - Thomas P Davis
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia; Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
| | - Pu Chun Ke
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia.
| | - Feng Ding
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, USA.
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53
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Lee YH, Lin Y, Cox SJ, Kinoshita M, Sahoo BR, Ivanova M, Ramamoorthy A. Zinc boosts EGCG's hIAPP amyloid Inhibition both in solution and membrane. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1867:529-536. [PMID: 30468883 DOI: 10.1016/j.bbapap.2018.11.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/14/2018] [Accepted: 11/17/2018] [Indexed: 12/22/2022]
Abstract
Amyloid aggregation of human islet amyloid polypeptide (hIAPP) is linked to insulin-producing islet cell death in type II diabetes. Previous studies have shown that zinc (Zn(II)) and insulin, co-secreted with hIAPP, have an inhibition effect on hIAPP aggregation. Lipid membranes have also been shown to significantly influence the aggregation kinetics of hIAPP. An increasing number of studies report the importance of developing small molecule inhibitors to suppress the hIAPP's aggregation and subsequent toxicity. The ability of epigallocatechin-gallate (EGCG) to inhibit aggregation of a variety of amyloid peptide/proteins initiated numerous studies as well as the development of derivative compounds to potentially treat amyloid diseases. In this study, a combination of Thioflavin-T fluorescence kinetics, transmission electron microscopy, isothermal titration calorimetery, circular dicrosim and nucelar magnetic resonance experiments were used to demonstrate a significant enhancement in EGCG's efficiency when complexed with Zn(II). We demonstrate that the Zn-EGCG complex is able to significantly suppress hIAPP's amyloid aggregation both in presence and absence of lipid membrane. Circular dichroism experiments indicate the formation and stabilization of a helical structure of hIAPP in presence of the EGCG:Zn(II) complex. Our results also reveal the ability of EGCG or EGCG:Zn(II) to efficiently suppress hIAPP's cellular toxicity. We believe that the reported results could be useful to develop strategies to trap hIAPP intermediates for further biophysical and structural studies, and also to devise approaches to abolish amyloid aggregation and cellular toxicity.
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Affiliation(s)
- Young-Ho Lee
- Institute for Protein research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan; Protein Structure Research Group, Division of Bioconvergence Analysis, Korea Basic Science Institute, Chungcheongbuk-do 28119, South Korea
| | - Yuxi Lin
- Department of Chemistry, Sookmyung Women's University, Cheongpa-ro 47-gil 100, Yongsan-gu, Seoul 04310, South Korea
| | - Sarah J Cox
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Misaki Kinoshita
- Institute for Protein research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
| | - Bikash R Sahoo
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Magdalena Ivanova
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
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54
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Mo Y, Brahmachari S, Lei J, Gilead S, Tang Y, Gazit E, Wei G. The Inhibitory Effect of Hydroxylated Carbon Nanotubes on the Aggregation of Human Islet Amyloid Polypeptide Revealed by a Combined Computational and Experimental Study. ACS Chem Neurosci 2018; 9:2741-2752. [PMID: 29986579 DOI: 10.1021/acschemneuro.8b00166] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Fibrillar deposits formed by the aggregation of the human islet amyloid polypeptide (hIAPP) are the major pathological hallmark of type 2 diabetes mellitus (T2DM). Inhibiting the aggregation of hIAPP is considered the primary therapeutic strategy for the treatment of T2DM. Hydroxylated carbon nanoparticles have received great attention in impeding amyloid protein fibrillation owing to their reduced cytotoxicity compared to the pristine ones. In this study, we investigated the influence of hydroxylated single-walled carbon nanotubes (SWCNT-OHs) on the first step of hIAPP aggregation: dimerization by performing explicit solvent replica exchange molecular dynamics (REMD) simulations. Extensive REMD simulations demonstrate that SWCNT-OHs can dramatically inhibit interpeptide β-sheet formation and completely suppress the previously reported β-hairpin amyloidogenic precursor of hIAPP. On the basis of our simulation results, we proposed that SWCNT-OH can hinder hIAPP fibrillation. This was further confirmed by our systematic turbidity measurements, thioflavin T fluorescence, circular dichroism (CD), transmission electron microscope (TEM), and atomic force microscopy (AFM) experiments. Detailed analyses of hIAPP-SWCNT-OH interactions reveal that hydrogen bonding, van der Waals, and π-stacking interactions between hIAPP and SWCNT-OH significantly weaken the inter- and intrapeptide interactions that are crucial for β-sheet formation. Our collective computational and experimental data reveal not only the inhibitory effect but also the inhibitory mechanism of SWCNT-OH against hIAPP aggregation, thus providing new clues for the development of future drug candidates against T2DM.
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Affiliation(s)
- Yuxiang Mo
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Science (Ministry of Education), Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Fudan University, Shanghai 200433, People’s Republic of China
- College of Physical Science and Technology, Guangxi Normal University, 15 Yucai Road, Guilin 541004, People’s Republic of China
| | - Sayanti Brahmachari
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Jiangtao Lei
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Science (Ministry of Education), Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Fudan University, Shanghai 200433, People’s Republic of China
| | - Sharon Gilead
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Yiming Tang
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Science (Ministry of Education), Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Fudan University, Shanghai 200433, People’s Republic of China
| | - Ehud Gazit
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Guanghong Wei
- State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Science (Ministry of Education), Collaborative Innovation Center of Advanced Microstructures, and Department of Physics, Fudan University, Shanghai 200433, People’s Republic of China
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55
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Wang M, Sun Y, Cao X, Peng G, Javed I, Kakinen A, Davis TP, Lin S, Liu J, Ding F, Ke PC. Graphene quantum dots against human IAPP aggregation and toxicity in vivo. NANOSCALE 2018; 10:19995-20006. [PMID: 30350837 PMCID: PMC6212334 DOI: 10.1039/c8nr07180b] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The development of biocompatible nanomaterials has become a new frontier in the detection, treatment and prevention of human amyloid diseases. Here we demonstrated the use of graphene quantum dots (GQDs) as a potent inhibitor against the in vivo aggregation and toxicity of human islet amyloid polypeptide (IAPP), a hallmark of type 2 diabetes. GQDs initiated contact with IAPP through electrostatic and hydrophobic interactions as well as hydrogen bonding, which subsequently drove the peptide fibrillization off-pathway to eliminate the toxic intermediates. Such interactions, probed in vitro by a thioflavin T kinetic assay, fluorescence quenching, circular dichroism spectroscopy, a cell viability assay and in silico by discrete molecular dynamics simulations, translated to a significant recovery of embryonic zebrafish from the damage elicited by IAPP in vivo, as indicated by improved hatching as well as alleviated reactive oxygen species production, abnormality and mortality of the organism. This study points to the potential of using zero-dimensional nanomaterials for in vivo mitigation of a range of amyloidosis.
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Affiliation(s)
- Miaoyi Wang
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- College of Environmental Science and Engineering, Biomedical Multidisciplinary Innovation Research Institute, Shanghai East Hospital, Shanghai Institute of Pollution Control and Ecological Security, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yunxiang Sun
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, USA
| | - Xueying Cao
- College of Materials Science and Engineering, Institute for Graphene Applied Technology Innovation, Qingdao University, Qingdao 266071, China
| | - Guotao Peng
- College of Environmental Science and Engineering, Biomedical Multidisciplinary Innovation Research Institute, Shanghai East Hospital, Shanghai Institute of Pollution Control and Ecological Security, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Ibrahim Javed
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Aleksandr Kakinen
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Thomas P. Davis
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
| | - Sijie Lin
- College of Environmental Science and Engineering, Biomedical Multidisciplinary Innovation Research Institute, Shanghai East Hospital, Shanghai Institute of Pollution Control and Ecological Security, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Jingquan Liu
- College of Materials Science and Engineering, Institute for Graphene Applied Technology Innovation, Qingdao University, Qingdao 266071, China
| | - Feng Ding
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, USA
| | - Pu Chun Ke
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
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56
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Giorgetti S, Greco C, Tortora P, Aprile FA. Targeting Amyloid Aggregation: An Overview of Strategies and Mechanisms. Int J Mol Sci 2018; 19:E2677. [PMID: 30205618 PMCID: PMC6164555 DOI: 10.3390/ijms19092677] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/02/2018] [Accepted: 09/05/2018] [Indexed: 12/26/2022] Open
Abstract
Amyloids result from the aggregation of a set of diverse proteins, due to either specific mutations or promoting intra- or extra-cellular conditions. Structurally, they are rich in intermolecular β-sheets and are the causative agents of several diseases, both neurodegenerative and systemic. It is believed that the most toxic species are small aggregates, referred to as oligomers, rather than the final fibrillar assemblies. Their mechanisms of toxicity are mostly mediated by aberrant interactions with the cell membranes, with resulting derangement of membrane-related functions. Much effort is being exerted in the search for natural antiamyloid agents, and/or in the development of synthetic molecules. Actually, it is well documented that the prevention of amyloid aggregation results in several cytoprotective effects. Here, we portray the state of the art in the field. Several natural compounds are effective antiamyloid agents, notably tetracyclines and polyphenols. They are generally non-specific, as documented by their partially overlapping mechanisms and the capability to interfere with the aggregation of several unrelated proteins. Among rationally designed molecules, we mention the prominent examples of β-breakers peptides, whole antibodies and fragments thereof, and the special case of drugs with contrasting transthyretin aggregation. In this framework, we stress the pivotal role of the computational approaches. When combined with biophysical methods, in several cases they have helped clarify in detail the protein/drug modes of interaction, which makes it plausible that more effective drugs will be developed in the future.
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Affiliation(s)
- Sofia Giorgetti
- Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Via Taramelli 3b, 27100 Pavia, Italy.
| | - Claudio Greco
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italy.
| | - Paolo Tortora
- Department of Biotechnologies and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy.
- Milan Center for Neuroscience (Neuro-MI), 20126 Milano, Italy.
| | - Francesco Antonio Aprile
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, UK.
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57
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Qian Z, Zou Y, Zhang Q, Chen P, Ma B, Wei G, Nussinov R. Atomistic-level study of the interactions between hIAPP protofibrils and membranes: Influence of pH and lipid composition. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2018; 1860:1818-1825. [PMID: 29428499 PMCID: PMC6408309 DOI: 10.1016/j.bbamem.2018.02.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 02/01/2018] [Accepted: 02/03/2018] [Indexed: 01/25/2023]
Abstract
The pathology of type 2 diabetes mellitus is associated with the aggregation of human islet amyloid polypeptide (hIAPP) and aggregation-mediated membrane disruption. The interactions of hIAPP aggregates with lipid membrane, as well as the effects of pH and lipid composition at the atomic level, remain elusive. Herein, using molecular dynamics simulations, we investigate the interactions of hIAPP protofibrillar oligomers with lipids, and the membrane perturbation that they induce, when they are partially inserted in an anionic dipalmitoyl-phosphatidylglycerol (DPPG) membrane or a mixed dipalmitoyl-phosphatidylcholine (DPPC)/DPPG (7:3) lipid bilayer under acidic/neutral pH conditions. We observed that the tilt angles and insertion depths of the hIAPP protofibril are strongly correlated with the pH and lipid composition. At neutral pH, the tilt angle and insertion depth of hIAPP protofibrils at a DPPG bilayer reach ~52° and ~1.62 nm with respect to the membrane surface, while they become ~77° and ~1.75 nm at a mixed DPPC/DPPG membrane. The calculated tilt angle of hIAPP at DPPG membrane is consistent with a recent chiral sum frequency generation spectroscopic study. The acidic pH induces a smaller tilt angle of ~40° and a shallower insertion depth (~1.24 nm) of hIAPP at the DPPG membrane surface, mainly due to protonation of His18 near the turn region. These differences mainly result from a combination of distinct electrostatic, van der Waals, hydrogen bonding and salt-bridge interactions between hIAPP and lipid bilayers. The hIAPP-membrane interaction energy analysis reveals that besides charged residues K1, R11 and H18, aromatic residues Phe15 and Phe23 also exhibit strong interactions with lipid bilayers, revealing the crucial role of aromatic residues in stabilizing the membrane-bound hIAPP protofibrils. hIAPP-membrane interactions disturb the lipid ordering and the local bilayer thickness around the peptides. Our results provide atomic-level information of membrane interaction of hIAPP protofibrils, revealing pH-dependent and membrane-modulated hIAPP aggregation at the early stage.
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Affiliation(s)
- Zhenyu Qian
- Key Laboratory of Exercise and Health Sciences (Ministry of Education) and School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China; Department of Physics, State Key Laboratory of Surface physics, Key Laboratory for Computational Physical Science (Ministry of Education), and Collaborative Innovation Center of Advanced Microstructures (Nanjing), Fudan University, Shanghai 200433, China
| | - Yu Zou
- College of Physical Education and Training, Shanghai University of Sport, Shanghai 200438, China
| | - Qingwen Zhang
- College of Physical Education and Training, Shanghai University of Sport, Shanghai 200438, China
| | - Peijie Chen
- Key Laboratory of Exercise and Health Sciences (Ministry of Education) and School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, United States
| | - Guanghong Wei
- Department of Physics, State Key Laboratory of Surface physics, Key Laboratory for Computational Physical Science (Ministry of Education), and Collaborative Innovation Center of Advanced Microstructures (Nanjing), Fudan University, Shanghai 200433, China.
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, United States; Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Sackler Institute of Molecular Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
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58
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Analysis of multiply charged monomers and dimers of human islet amyloid polypeptide by collision-induced dissociation with electrospray ionization mass spectrometry. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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59
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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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60
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Das P, Matysiak S, Mittal J. Looking at the Disordered Proteins through the Computational Microscope. ACS CENTRAL SCIENCE 2018; 4:534-542. [PMID: 29805999 PMCID: PMC5968442 DOI: 10.1021/acscentsci.7b00626] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Indexed: 05/04/2023]
Abstract
Intrinsically disordered proteins (IDPs) have attracted wide interest over the past decade due to their surprising prevalence in the proteome and versatile roles in cell physiology and pathology. A large selection of IDPs has been identified as potential targets for therapeutic intervention. Characterizing the structure-function relationship of disordered proteins is therefore an essential but daunting task, as these proteins can adapt transient structure, necessitating a new paradigm for connecting structural disorder to function. Molecular simulation has emerged as a natural complement to experiments for atomic-level characterizations and mechanistic investigations of this intriguing class of proteins. The diverse range of length and time scales involved in IDP function requires performing simulations at multiple levels of resolution. In this Outlook, we focus on summarizing available simulation methods, along with a few interesting example applications. We also provide an outlook on how these simulation methods can be further improved in order to provide a more accurate description of IDP structure, binding, and assembly.
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Affiliation(s)
- Payel Das
- IBM Thomas J.
Watson Research Center, Yorktown Heights, New York 10598, United States
- E-mail:
| | - Silvina Matysiak
- Fischell
Department of Bioengineering, University
of Maryland, College Park, Maryland 20742, United States
| | - Jeetain Mittal
- Department
of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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61
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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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62
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Ge X, Sun Y, Ding F. Structures and dynamics of β-barrel oligomer intermediates of amyloid-beta16-22 aggregation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1687-1697. [PMID: 29550287 DOI: 10.1016/j.bbamem.2018.03.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/06/2018] [Accepted: 03/07/2018] [Indexed: 01/13/2023]
Abstract
Accumulating evidence suggests that soluble oligomers are more toxic than final fibrils of amyloid aggregations. Among the mixture of inter-converting intermediates with continuous distribution of sizes and secondary structures, oligomers in the β-barrel conformation - a common class of protein folds with a closed β-sheet - have been postulated as the toxic species with well-defined three-dimensional structures to perform pathological functions. A common mechanism for amyloid toxicity, therefore, implies that all amyloid peptides should be able to form β-barrel oligomers as the aggregation intermediates. Here, we applied all-atom discrete molecular dynamics (DMD) simulations to evaluate the formation of β-barrel oligomers and characterize their structures and dynamics in the aggregation of a seven-residue amyloid peptide, corresponding to the amyloid core of amyloid-β with a sequence of 16KLVFFAE22 (Aβ16-22). We carried out aggregation simulations with various numbers of peptides to study the size dependence of aggregation dynamics and assembly structures. Consistent with previous computational studies, we observed the formation of β-barrel oligomers in all-atom DMD simulations. Using a network-based approach to automatically identify β-barrel conformations, we systematically characterized β-barrels of various sizes. Our simulations revealed the conformational inter-conversion between β-barrels and double-layer β-sheets due to increased structural strains upon forming a closed β-barrel while maximizing backbone hydrogen bonds. The potential of mean force analysis further characterized the free energy barriers between these two states. The obtained structural and dynamic insights of β-barrel oligomers may help better understand the molecular mechanism of oligomer toxicities and design novel therapeutics targeting the toxic β-barrel oligomers. 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)
- Xinwei Ge
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
| | - Yunxiang Sun
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
| | - Feng Ding
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States.
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63
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Dong X, Qiao Q, Qian Z, Wei G. Recent computational studies of membrane interaction and disruption of human islet amyloid polypeptide: Monomers, oligomers and protofibrils. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018. [PMID: 29530482 DOI: 10.1016/j.bbamem.2018.03.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The amyloid deposits of human islet amyloid polypeptide (hIAPP) are found in type 2 diabetes patients. hIAPP monomer is intrinsically disordered in solution, whereas it can form amyloid fibrils both in vivo and in vitro. Extensive evidence suggests that hIAPP causes the disruption of cellular membrane, and further induces cytotoxicity and the death of islet β-cells in pancreas. The presence of membrane also accelerates the hIAPP fibril formation. hIAPP oligomers and protofibrils in the early stage of aggregation were reported to be the most cytotoxic, disrupting the membrane integrity and giving rise to the pathological process. The detailed molecular mechanisms of hIAPP-membrane interactions and membrane disruption are complex and remain mostly unknown. Here in this review, we focus on recent computational studies that investigated the interactions of full length and fragmentary hIAPP monomers, oligomers and protofibrils with anionic, zwitterionic and mixed anionic-zwitterionic lipid bilayers. We mainly discuss the binding orientation of monomers at membrane surface, the conformational ensemble and the oligomerization of hIAPP inside membranes, the effect of lipid composition on hIAPP oligomers/protofibrils-membrane interactions, and the hIAPP-induced membrane perturbation. This review provides mechanistic insights into the interactions between hIAPP and lipid bilayers with different lipid composition at an atomistic level, which is helpful to understand the hIAPP cytotoxicity mediated by membrane. 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)
- Xuewei Dong
- Department of Physics, State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Science (Ministry of Education), Collaborative Innovation Center of Advanced Microstructures (Nanjing), Fudan University, Shanghai 200433, China
| | - Qin Qiao
- Digital Medical Research Center, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China; Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention, Shanghai 200032, China.
| | - Zhenyu Qian
- Key Laboratory of Exercise and Health Sciences (Ministry of Education) and School of Kinesiology, Shanghai University of Sport, Shanghai 200438, China
| | - Guanghong Wei
- Department of Physics, State Key Laboratory of Surface Physics, Key Laboratory for Computational Physical Science (Ministry of Education), Collaborative Innovation Center of Advanced Microstructures (Nanjing), Fudan University, Shanghai 200433, China.
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64
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IAPP/amylin and β-cell failure: implication of the risk factors of type 2 diabetes. Diabetol Int 2018; 9:143-157. [PMID: 30603362 DOI: 10.1007/s13340-018-0347-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 01/21/2018] [Indexed: 12/12/2022]
Abstract
In type 2 diabetes (T2D), the most significant pathological change in pancreatic islets is amyloid deposits, of which a major component is islet amyloid polypeptide (IAPP), also called amylin. IAPP is expressed in β-cells and co-secreted with insulin. Together with the inhibitory effects of synthetic human IAPP (hIAPP) on insulin secretion, our studies, using hIAPP transgenic mice, in which glucose-stimulated insulin secretion was moderately reduced without amyloid deposit, and hIAPP gene-transfected β-cell lines, in which insulin secretion was markedly impaired without amyloid, predicted that soluble hIAPP-related molecules would exert cytotoxicity on β-cells. Human IAPP is one of the most aggregation-prone peptides that interact with cell membranes. While it is widely reported that soluble hIAPP oligomers promote cytotoxicity, this is still a hypothesis since the mechanisms are not yet fully defined. Several hIAPP transgenic mouse models did not develop diabetes; however, in models with backgrounds characterized for diabetic phenotypes, β-cell function and glucose tolerance did worsen, compared to those in non-transgenic models with similar backgrounds. Together with these findings, many studies on metabolic and molecular disorders induced by risk factors of T2D suggest that in T2D subjects, toxic IAPP oligomers accumulate in β-cells, impair their function, and reduce mass through disruption of cell membranes, resulting in β-cell failure. IAPP might be central to β-cell failure in T2D. Anti-amyloid aggregation therapeutics will be developed to create treatments with more durable and beneficial effects on β-cell function.
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65
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Epigallocatechin gallate (EGCG) reduces the intensity of pancreatic amyloid fibrils in human islet amyloid polypeptide (hIAPP) transgenic mice. Sci Rep 2018; 8:1116. [PMID: 29348618 PMCID: PMC5773570 DOI: 10.1038/s41598-017-18807-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 12/15/2017] [Indexed: 01/27/2023] Open
Abstract
The formation of amyloid fibrils by human islet amyloid polypeptide protein (hIAPP) has been implicated in pancreas dysfunction and diabetes. However, efficient treatment options to reduce amyloid fibrils in vivo are still lacking. Therefore, we tested the effect of epigallocatechin gallate (EGCG) on fibril formation in vitro and in vivo. To determine the binding of hIAPP and EGCG, in vitro interaction studies were performed. To inhibit amyloid plaque formation in vivo, homozygous (tg/tg), hemizygous (wt/tg), and control mice (wt/wt) were treated with EGCG. EGCG bound to hIAPP in vitro and induced formation of amorphous aggregates instead of amyloid fibrils. Amyloid fibrils were detected in the pancreatic islets of tg/tg mice, which was associated with disrupted islet structure and diabetes. Although pancreatic amyloid fibrils could be detected in wt/tg mice, these animals were non-diabetic. EGCG application decreased amyloid fibril intensity in wt/tg mice, however it was ineffective in tg/tg animals. Our data indicate that EGCG inhibits amyloid fibril formation in vitro and reduces fibril intensity in non-diabetic wt/tg mice. These results demonstrate a possible in vivo effectiveness of EGCG on amyloid formation and suggest an early therapeutical application.
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66
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Jamal S, Kumari A, Singh A, Goyal S, Grover A. Conformational Ensembles of α-Synuclein Derived Peptide with Different Osmolytes from Temperature Replica Exchange Sampling. Front Neurosci 2017; 11:684. [PMID: 29270108 PMCID: PMC5725442 DOI: 10.3389/fnins.2017.00684] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 11/22/2017] [Indexed: 11/13/2022] Open
Abstract
Intrinsically disordered proteins (IDP) are a class of proteins that do not have a stable three-dimensional structure and can adopt a range of conformations playing various vital functional role. Alpha-synuclein is one such IDP which can aggregate into toxic protofibrils and has been associated largely with Parkinson's disease (PD) along with other neurodegenerative diseases. Osmolytes are small organic compounds that can alter the environment around the proteins by acting as denaturants or protectants for the proteins. In the present study, we have conducted a series of replica exchange molecular dynamics simulations to explore the role of osmolytes, urea which is a denaturant and TMAO (trimethylamine N-oxide), a protecting osmolyte, in aggregation and conformations of the synuclein peptide. We observed that both the osmolytes have significantly distinct impacts on the peptide and led to transitions of the conformations of the peptide from one state to other. Our findings highlighted that urea attenuated peptide aggregation and resulted in the formation of extended peptide structures whereas TMAO led to compact and folded forms of the peptide.
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Affiliation(s)
- Salma Jamal
- Department of Bioscience and Biotechnology, Banasthali University, Tonk, India
| | - Anchala Kumari
- Department of Biotechnology, TERI School of Advanced Studies, New Delhi, India
| | - Aditi Singh
- Department of Biotechnology, TERI School of Advanced Studies, New Delhi, India
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Sukriti Goyal
- Department of Bioscience and Biotechnology, Banasthali University, Tonk, India
| | - Abhinav Grover
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
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67
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Zhou S, Liu X, An X, Yao X, Liu H. Molecular Dynamics Simulation Study on the Binding and Stabilization Mechanism of Antiprion Compounds to the "Hot Spot" Region of PrP C. ACS Chem Neurosci 2017; 8:2446-2456. [PMID: 28795797 DOI: 10.1021/acschemneuro.7b00214] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Structural transitions in the prion protein from the cellular form, PrPC, into the pathological isoform, PrPSc, are regarded as the main cause of the transmissible spongiform encephalopathies, also known as prion diseases. Hence, discovering and designing effective antiprion drugs that can inhibit PrPC to PrPSc conversion is regarded as a promising way to cure prion disease. Among several strategies to inhibit PrPC to PrPSc conversion, stabilizing the native PrPC via specific binding is believed to be one of the valuable approaches and many antiprion compounds have been reported based on this strategy. However, the detailed mechanism to stabilize the native PrPC is still unknown. As such, to unravel the stabilizing mechanism of these compounds to PrPC is valuable for the further design and discovery of antiprion compounds. In this study, by molecular dynamics simulation method, we investigated the stabilizing mechanism of several antiprion compounds on PrPC that were previously reported to have specific binding to the "hot spot" region of PrPC. Our simulation results reveal that the stabilization mechanism of specific binding compounds can be summarized as (I) to stabilize both the flexible C-terminal of α2 and the hydrophobic core, such as BMD42-29 and GN8; (II) to stabilize the hydrophobic core, such as J1 and GJP49; (III) to stabilize the overall structure of PrPC by high binding affinity, as NPR-056. In addition, as indicated by the H-bond analysis and decomposition analysis of binding free energy, the residues N159 and Q160 play an important role in the specific binding of the studied compounds and all these compounds interact with PrPC in a similar way with the key interacting residues L130 in the β1 strand, P158, N159, Q160, etc. in the α1-β2 loop, and H187, T190, T191, etc. in the α2 C-terminus although the compounds have large structural difference. As a whole, our obtained results can provide some insights into the specific binding mechanism of main antiprion compounds to the "hot spot" region of PrPC at the molecular level and also provide guidance for effective antiprion drug design in the future.
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Affiliation(s)
- Shuangyan Zhou
- School of Pharmacy, Lanzhou University, Lanzhou 730000, China
| | - Xuewei Liu
- State Key Laboratory of Applied Organic Chemistry and
Department of Chemistry, Lanzhou University, Lanzhou 730000, China
| | - Xiaoli An
- State Key Laboratory of Applied Organic Chemistry and
Department of Chemistry, Lanzhou University, Lanzhou 730000, China
| | - Xiaojun Yao
- State Key Laboratory of Applied Organic Chemistry and
Department of Chemistry, Lanzhou University, Lanzhou 730000, China
- State Key Laboratory of Quality Research
in Chinese Medicine, Macau Institute for Applied Research in Medicine
and Health, Macau University of Science and Technology, Taipa, Macau, China
| | - Huanxiang Liu
- School of Pharmacy, Lanzhou University, Lanzhou 730000, China
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68
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Sun Y, Wang B, Ge X, Ding F. Distinct oligomerization and fibrillization dynamics of amyloid core sequences of amyloid-beta and islet amyloid polypeptide. Phys Chem Chem Phys 2017; 19:28414-28423. [PMID: 29038815 PMCID: PMC5657190 DOI: 10.1039/c7cp05695h] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A direct observation of amyloid aggregation from isolated peptides to cross-β fibrils is crucial for understanding the nucleation-dependence process, but the corresponding macroscopic timescales impose a major computational challenge. Using rapid all-atom discrete molecular dynamics simulations, we capture the oligomerization and fibrillization dynamics of the amyloid core sequences of amyloid-β (Aβ) in Alzheimer's disease and islet amyloid polypeptide (IAPP) in type-2 diabetes, namely Aβ16-22 and IAPP22-28. Both peptides and their mixture spontaneously assemble into cross-β aggregates in silico, but follow distinct pathways. Aβ16-22 is highly aggregation-prone with a funneled free energy basin toward multi-layer β-sheet aggregates. IAPP22-28, on the other hand, features the accumulation of unstructured oligomers before the nucleation of β-sheets and growth into double-layer β-sheet aggregates. In the presence of Aβ16-22, the aggregation of IAPP22-28 is promoted by forming co-aggregated multi-layer β-sheets. Our study offers a detailed molecular insight to the long-postulated oligomerization-nucleation process in the amyloid aggregations.
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Affiliation(s)
- Yunxiang Sun
- Department of Physics and Astronomy, Clemson University, Clemson, SC, USA.
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69
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Zou Y, Qian Z, Sun Y, Wei G, Zhang Q. Orcein-Related Small Molecule O4 Destabilizes hIAPP Protofibrils by Interacting Mostly with the Amyloidogenic Core Region. J Phys Chem B 2017; 121:9203-9212. [DOI: 10.1021/acs.jpcb.7b08652] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | - Yunxiang Sun
- State
Key Laboratory of Surface Physics, Key Laboratory for Computational
Physical Sciences (MOE), and Department of Physics, Fudan University, 220
Handan Road, Shanghai 200433, China
| | - Guanghong Wei
- State
Key Laboratory of Surface Physics, Key Laboratory for Computational
Physical Sciences (MOE), and Department of Physics, Fudan University, 220
Handan Road, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
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70
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Christensen M, Skeby KK, Schiøtt B. Identification of Key Interactions in the Initial Self-Assembly of Amylin in a Membrane Environment. Biochemistry 2017; 56:4884-4894. [PMID: 28786287 DOI: 10.1021/acs.biochem.7b00344] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Islet amyloid polypeptide, also known as amylin, forms aggregates that reduce the amount of insulin-producing cells in patients with type II diabetes mellitus. Much remains unknown about the process of aggregation and cytotoxicity, but it is known that certain cell membrane components can alter the rate of aggregation. Using atomistic molecular dynamics simulations combined with the highly mobile membrane mimetic model incorporating enhanced sampling of lipid diffusion, we investigate interaction of amylin peptides with the membrane components as well as the self-assembly of amylin. Consistent with experimental evidence, we find that an initial membrane-bound α-helical state folds into stable β-sheet structures upon self-assembly. Our results suggest the following mechanism for the initial phase of amylin self-assembly. The peptides move around on the membrane with the positively charged N-terminus interacting with the negatively charged lipid headgroups. When the peptides start to interact, they partly unfold and break some of the contacts with the membrane. The initial interactions between the peptides are dominated by aromatic and hydrophobic interactions. Oligomers are formed showing both intra- and interpeptide β-sheets, initially with interactions mainly in the C-terminal domain of the peptides. Decreasing the pH to 5.5 is known to inhibit amyloid formation. At low pH, His18 is protonated, adding a fourth positive charge at the peptide. With His18 protonated, no oligomerization is observed in the simulations. The additional charge gives a strong midpoint anchoring of the peptides to negatively charged membrane components, and the peptides experience additional interpeptide repulsion, thereby preventing interactions.
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Affiliation(s)
- Mikkel Christensen
- Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark.,Sino-Danish Center for Education and Research , Beijing, China
| | - Katrine K Skeby
- Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark
| | - Birgit Schiøtt
- Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark
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71
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Structural Properties of Human IAPP Dimer in Membrane Environment Studied by All-Atom Molecular Dynamics Simulations. Sci Rep 2017; 7:7915. [PMID: 28801684 PMCID: PMC5554177 DOI: 10.1038/s41598-017-08504-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 07/12/2017] [Indexed: 12/27/2022] Open
Abstract
The aggregation of human islet amyloid polypeptide (hIAPP) can damage the membrane of the β-cells in the pancreatic islets and induce type 2 diabetes (T2D). Growing evidences indicated that the major toxic species are small oligomers of IAPP. Due to the fast aggregation nature, it is hard to characterize the structures of IAPP oligomers by experiments, especially in the complex membrane environment. On the other side, molecular dynamics simulation can provide atomic details of the structure and dynamics of the aggregation of IAPP. In this study, all-atom bias-exchange metadynamics (BE-Meta) and unbiased molecular dynamics simulations were employed to study the structural properties of IAPP dimer in the membranes environments. A number of intermediates, including α-helical states, β-sheet states, and fully disordered states, are identified. The formation of N-terminal β-sheet structure is prior to the C-terminal β-sheet structure towards the final fibril-like structures. The α-helical intermediates have lower propensity in the dimeric hIAPP and are off-pathway intermediates. The simulations also demonstrate that the β-sheet intermediates induce more perturbation on the membrane than the α-helical and disordered states and thus pose higher disruption ability.
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72
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Velander P, Wu L, Henderson F, Zhang S, Bevan DR, Xu B. Natural product-based amyloid inhibitors. Biochem Pharmacol 2017; 139:40-55. [PMID: 28390938 DOI: 10.1016/j.bcp.2017.04.004] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 04/03/2017] [Indexed: 11/26/2022]
Abstract
Many chronic human diseases, including multiple neurodegenerative diseases, are associated with deleterious protein aggregates, also called protein amyloids. One common therapeutic strategy is to develop protein aggregation inhibitors that can slow down, prevent, or remodel toxic amyloids. Natural products are a major class of amyloid inhibitors, and several dozens of natural product-based amyloid inhibitors have been identified and characterized in recent years. These plant- or microorganism-extracted compounds have shown significant therapeutic potential from in vitro studies as well as in vivo animal tests. Despite the technical challenges of intrinsic disordered or partially unfolded amyloid proteins that are less amenable to characterizations by structural biology, a significant amount of research has been performed, yielding biochemical and pharmacological insights into how inhibitors function. This review aims to summarize recent progress in natural product-based amyloid inhibitors and to analyze their mechanisms of inhibition in vitro. Major classes of natural product inhibitors and how they were identified are described. Our analyses comprehensively address the molecular interactions between the inhibitors and relevant amyloidogenic proteins. These interactions are delineated at molecular and atomic levels, which include covalent, non-covalent, and metal-mediated mechanisms. In vivo animal studies and clinical trials have been summarized as an extension. To enhance natural product bioavailability in vivo, emerging work using nanocarriers for delivery has also been described. Finally, issues and challenges as well as future development of such inhibitors are envisioned.
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Affiliation(s)
- Paul Velander
- Department of Biochemistry, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA
| | - Ling Wu
- Department of Biochemistry, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA
| | - Frances Henderson
- Department of Biochemistry, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA
| | - Shijun Zhang
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - David R Bevan
- Department of Biochemistry, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA; Center for Drug Discovery, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA; School of Neuroscience, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA
| | - Bin Xu
- Department of Biochemistry, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA; Center for Drug Discovery, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA; School of Neuroscience, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA; Translational Obesity Research Center, Virginia Polytechnic Institute & State University, Blacksburg, VA 24061, USA.
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73
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Zhou S, Wang Q, Ren M, Zhang A, Liu H, Yao X. Molecular dynamics simulation on the inhibition mechanism of peptide-based inhibitor of islet amyloid polypeptide (IAPP) to islet amyloid polypeptide (IAPP22-28) oligomers. Chem Biol Drug Des 2017; 90:31-39. [DOI: 10.1111/cbdd.12924] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 11/18/2016] [Accepted: 11/27/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Shuangyan Zhou
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry; Lanzhou University; Lanzhou China
- School of Pharmacy; Lanzhou University; Lanzhou China
| | - Qianqian Wang
- State Key Laboratory of Quality Research in Chinese Medicine; Macau Institute for Applied Research in Medicine and Health; Macau University of Science and Technology; Taipa Macau China
| | - Mengdan Ren
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry; Lanzhou University; Lanzhou China
| | - Ai Zhang
- School of Pharmacy; Lanzhou University; Lanzhou China
| | - Huanxiang Liu
- School of Pharmacy; Lanzhou University; Lanzhou China
| | - Xiaojun Yao
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry; Lanzhou University; Lanzhou China
- State Key Laboratory of Quality Research in Chinese Medicine; Macau Institute for Applied Research in Medicine and Health; Macau University of Science and Technology; Taipa Macau China
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74
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Guo J, Sun W, Li L, Liu F, Lu W. Brazilin inhibits fibrillogenesis of human islet amyloid polypeptide, disassembles mature fibrils, and alleviates cytotoxicity. RSC Adv 2017. [DOI: 10.1039/c7ra05742c] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Inhibitory effect of brazilin on the fibrillogenesis of hIAPP was explored using biochemical, biophysical, cytobiological and molecular simulation experiments. Brazilin was a potential compound for therapeutic treatment of type II diabetes mellitus.
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Affiliation(s)
- Jingjing Guo
- Department of Biochemical Engineering
- Key Laboratory of Systems Bioengineering of Ministry of Education
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
| | - Wanqi Sun
- Department of Chemical and Biological Engineering
- The University of Alabama
- Tuscaloosa
- USA
| | - Li Li
- College of Marine and Environmental Sciences
- Tianjin University of Science & Technology
- Tianjin 300457
- P. R. China
| | - Fufeng Liu
- Department of Biochemical Engineering
- Key Laboratory of Systems Bioengineering of Ministry of Education
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
| | - Wenyu Lu
- Department of Biochemical Engineering
- Key Laboratory of Systems Bioengineering of Ministry of Education
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300072
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