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Nilsson BL, Celebi Torabfam G, Dias CL. Peptide Self-Assembly into Amyloid Fibrils: Unbiased All-Atom Simulations. J Phys Chem B 2024; 128:3320-3328. [PMID: 38447080 DOI: 10.1021/acs.jpcb.3c07861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Protein self-assembly plays an important role in biological systems, accounting for the formation of mesoscopic structures that can be highly symmetric as in the capsid of viruses or disordered as in molecular condensates or exhibit a one-dimensional fibrillar morphology as in amyloid fibrils. Deposits of the latter in tissues of individuals with degenerative diseases like Alzheimer's and Parkinson's has motivated extensive efforts to understand the sequence of molecular events accounting for their formation. These studies aim to identify on-pathway intermediates that may be the targets for therapeutic intervention. This detailed knowledge of fibril formation remains obscure, in part due to challenges with experimental analyses of these processes. However, important progress is being achieved for short amyloid peptides due to advances in our ability to perform completely unbiased all-atom simulations of the self-assembly process. This perspective discusses recent developments, their implications, and the hurdles that still need to be overcome to further advance the field.
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Affiliation(s)
- Bradley L Nilsson
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States
- Materials Science Program, University of Rochester, Rochester, New York 14627-0216, United States
| | - Gizem Celebi Torabfam
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102-1982, United States
| | - Cristiano L Dias
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102-1982, United States
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2
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Nutini A. Amyloid oligomers and their membrane toxicity - A perspective study. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2024; 187:9-20. [PMID: 38211711 DOI: 10.1016/j.pbiomolbio.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/21/2023] [Accepted: 01/07/2024] [Indexed: 01/13/2024]
Abstract
Amyloidosis is a condition involving a disparate group of pathologies characterized by the extracellular deposition of insoluble fibrils composed of broken-down proteins. These proteins can accumulate locally, causing peculiar symptoms, or in a widespread way, involving many organs and. causing severe systemic failure. The damage that is created is related not only to the accumulation of. amyloid fibrils but above all to the precursor oligomers of the fibrils that manage to enter the cell in a very particular way. This article analyzes the current state of research related to the entry of these oligomers into the cell membrane and the theories related to their toxicity. The paper proposed here not only aims to review the contents in the literature but also proposes a new vision of amyloid toxicity. that could occur in a multiphase process catalyzed by the cell membrane itself. In this process, the denaturation of the lipid bilayer is followed by the stabilization of a pore through energetically favorable self-assembly processes which are achieved through particular oligomeric structures.
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Affiliation(s)
- Alessandro Nutini
- Biology and Biomechanics Dept - Centro Studi Attività Motorie, Italy.
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3
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Zhang R, Jalali S, Dias CL, Haataja MP. Growth kinetics of amyloid-like fibrils: An integrated atomistic simulation and continuum theory approach. PNAS NEXUS 2024; 3:pgae045. [PMID: 38725528 PMCID: PMC11079572 DOI: 10.1093/pnasnexus/pgae045] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 01/19/2024] [Indexed: 05/12/2024]
Abstract
Amyloid fibrils have long been associated with many neurodegenerative diseases. The conventional picture of the formation and proliferation of fibrils from unfolded proteins comprises primary and secondary nucleation of oligomers followed by elongation and fragmentation thereof. In this work, we first employ extensive all-atom molecular dynamics (MD) simulations of short peptides to investigate the governing processes of fibril growth at the molecular scale. We observe that the peptides in the bulk solution can bind onto and subsequently diffuse along the fibril surface, which leads to fibril elongation via either bulk- or surface-mediated docking mechanisms. Then, to guide the quantitative interpretation of these observations and to provide a more comprehensive picture of the growth kinetics of single fibrils, a continuum model which incorporates the key processes observed in the MD simulations is formulated. The model is employed to investigate how relevant physical parameters affect the kinetics of fibril growth and identify distinct growth regimes. In particular, it is shown that fibrils which strongly bind peptides may undergo a transient exponential growth phase in which the entire fibril surface effectively acts as a sink for peptides. We also demonstrate how the relevant model parameters can be estimated from the MD trajectories. Our results provide compelling evidence that the overall fibril growth rates are determined by both bulk and surface peptide fluxes, thereby contributing to a more fundamental understanding of the growth kinetics of amyloid-like fibrils.
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Affiliation(s)
- Ruoyao Zhang
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Sharareh Jalali
- Department of Physics, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Cristiano Luis Dias
- Department of Physics, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - Mikko P Haataja
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
- Princeton Materials Institute, Princeton University, Princeton, NJ 08544, USA
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4
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Okumura H. Perspective for Molecular Dynamics Simulation Studies of Amyloid-β Aggregates. J Phys Chem B 2023; 127:10931-10940. [PMID: 38109338 DOI: 10.1021/acs.jpcb.3c06051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
The cause of Alzheimer's disease is related to aggregates such as oligomers and amyloid fibrils consisting of amyloid-β (Aβ) peptides. Molecular dynamics (MD) simulation studies have been conducted to understand the molecular mechanism of the formation and disruption of Aβ aggregates. In this Perspective, the MD simulation studies are classified into four categories, focusing on the target systems: aggregation of Aβ peptides in bulk solution, Aβ aggregation at the interface, aggregation inhibitor against Aβ peptides, and nonequilibrium MD simulation of Aβ aggregates. MD simulation studies in these categories are first reviewed. Future perspectives in each category are then presented. Finally, the overall perspective is presented on how MD simulations of Aβ aggregates can be utilized for developing Alzheimer's disease treatment.
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Affiliation(s)
- Hisashi Okumura
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Institute for Molecular Science, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Okazaki, Aichi 444-8787, Japan
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5
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Abstract
The formation of amyloid fibrils is a complex phenomenon that remains poorly understood at the atomic scale. Herein, we perform extended unbiased all-atom simulations in explicit solvent of a short amphipathic peptide to shed light on the three mechanisms accounting for fibril formation, namely, nucleation via primary and secondary mechanisms, and fibril growth. We find that primary nucleation takes place via the formation of an intermediate state made of two laminated β-sheets oriented perpendicular to each other. The amyloid fibril spine subsequently emerges from the rotation of these β-sheets to account for peptides that are parallel to each other and perpendicular to the main axis of the fibril. Growth of this spine, in turn, takes place via a dock-and-lock mechanism. We find that peptides dock onto the fibril tip either from bulk solution or after diffusing on the fibril surface. The latter docking pathway contributes significantly to populate the fibril tip with peptides. We also find that side chain interactions drive the motion of peptides in the lock phase during growth, enabling them to adopt the structure imposed by the fibril tip with atomic fidelity. Conversely, the docked peptide becomes trapped in a local free energy minimum when docked-conformations are sampled randomly. Our simulations also highlight the role played by nonpolar fibril surface patches in catalyzing and orienting the formation of small cross-β structures. More broadly, our simulations provide important new insights into the pathways and interactions accounting for primary and secondary nucleation as well as the growth of amyloid fibrils.
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Affiliation(s)
- Sharareh Jalali
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102-1982, United States
| | - Ruoyao Zhang
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Mikko P Haataja
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Princeton Materials Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Cristiano L Dias
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102-1982, United States
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6
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Roy D, Maity NC, Kumar S, Maity A, Ratha BN, Biswas R, Maiti NC, Mandal AK, Bhunia A. Modulatory role of copper on hIAPP aggregation and toxicity in presence of insulin. Int J Biol Macromol 2023; 241:124470. [PMID: 37088193 DOI: 10.1016/j.ijbiomac.2023.124470] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/24/2023] [Accepted: 04/12/2023] [Indexed: 04/25/2023]
Abstract
Aggregation of the human islets amyloid polypeptide, or hIAPP, is linked to β-cell death in type II diabetes mellitus (T2DM). Different pancreatic β-cell environmental variables such as pH, insulin and metal ions play a key role in controlling the hIAPP aggregation. Since insulin and hIAPP are co-secreted, it is known from numerous studies that insulin suppresses hIAPP fibrillation by preventing the initial dimerization process. On the other hand, zinc and copper each have an inhibitory impact on hIAPP fibrillation, but copper promotes the production of toxic oligomers. Interestingly, the insulin oligomeric equilibrium is controlled by the concentration of zinc ions when the effect of insulin and zinc has been tested together. Lower zinc concentrations cause the equilibrium to shift towards the monomer and dimer states of insulin, which bind to monomeric hIAPP and stop it from developing into a fibril. On the other hand, the combined effects of copper and insulin have not yet been done. In this study, we have demonstrated how the presence of copper affects hIAPP aggregation and the toxicity of the resultant conformers with or without insulin. For this purpose, we have used a set of biophysical techniques, including NMR, fluorescence, CD etc., in combination with AFM and cell cytotoxicity assay. In the presence and/or absence of insulin, copper induces hIAPP to form structurally distinct stable toxic oligomers, deterring the fibrillation process. More specifically, the oligomers generated in the presence of insulin have slightly higher toxicity than those formed in the absence of insulin. This research will increase our understanding of the combined modulatory effect of two β-cell environmental factors on hIAPP aggregation.
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Affiliation(s)
- Dipanwita Roy
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata 700091, India
| | - Narayan Chandra Maity
- Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Sector-III, Salt Lake, Kolkata 700106, India
| | - Sourav Kumar
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata 700091, India
| | - Anupam Maity
- Structural Biology and Bioinformatics, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Bhisma N Ratha
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata 700091, India
| | - Ranjit Biswas
- Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Sector-III, Salt Lake, Kolkata 700106, India
| | - Nakul Chandra Maiti
- Structural Biology and Bioinformatics, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Atin Kumar Mandal
- Division of Molecular Medicine, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata, 700091, India
| | - Anirban Bhunia
- Department of Biophysics, Bose Institute, Unified Academic Campus, Salt Lake, Sctor V, Kolkata 700091, India.
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Taylor AIP, Staniforth RA. General Principles Underpinning Amyloid Structure. Front Neurosci 2022; 16:878869. [PMID: 35720732 PMCID: PMC9201691 DOI: 10.3389/fnins.2022.878869] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/11/2022] [Indexed: 12/14/2022] Open
Abstract
Amyloid fibrils are a pathologically and functionally relevant state of protein folding, which is generally accessible to polypeptide chains and differs fundamentally from the globular state in terms of molecular symmetry, long-range conformational order, and supramolecular scale. Although amyloid structures are challenging to study, recent developments in techniques such as cryo-EM, solid-state NMR, and AFM have led to an explosion of information about the molecular and supramolecular organization of these assemblies. With these rapid advances, it is now possible to assess the prevalence and significance of proposed general structural features in the context of a diverse body of high-resolution models, and develop a unified view of the principles that control amyloid formation and give rise to their unique properties. Here, we show that, despite system-specific differences, there is a remarkable degree of commonality in both the structural motifs that amyloids adopt and the underlying principles responsible for them. We argue that the inherent geometric differences between amyloids and globular proteins shift the balance of stabilizing forces, predisposing amyloids to distinct molecular interaction motifs with a particular tendency for massive, lattice-like networks of mutually supporting interactions. This general property unites previously characterized structural features such as steric and polar zippers, and contributes to the long-range molecular order that gives amyloids many of their unique properties. The shared features of amyloid structures support the existence of shared structure-activity principles that explain their self-assembly, function, and pathogenesis, and instill hope in efforts to develop broad-spectrum modifiers of amyloid function and pathology.
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Gomes GN, Levine ZA. Defining the Neuropathological Aggresome across in Silico, in Vitro, and ex Vivo Experiments. J Phys Chem B 2021; 125:1974-1996. [PMID: 33464098 PMCID: PMC8362740 DOI: 10.1021/acs.jpcb.0c09193] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The loss of proteostasis over the life course is associated with a wide range of debilitating degenerative diseases and is a central hallmark of human aging. When left unchecked, proteins that are intrinsically disordered can pathologically aggregate into highly ordered fibrils, plaques, and tangles (termed amyloids), which are associated with countless disorders such as Alzheimer's disease, Parkinson's disease, type II diabetes, cancer, and even certain viral infections. However, despite significant advances in protein folding and solution biophysics techniques, determining the molecular cause of these conditions in humans has remained elusive. This has been due, in part, to recent discoveries showing that soluble protein oligomers, not insoluble fibrils or plaques, drive the majority of pathological processes. This has subsequently led researchers to focus instead on heterogeneous and often promiscuous protein oligomers. Unfortunately, significant gaps remain in how to prepare, model, experimentally corroborate, and extract amyloid oligomers relevant to human disease in a systematic manner. This Review will report on each of these techniques and their successes and shortcomings in an attempt to standardize comparisons between protein oligomers across disciplines, especially in the context of neurodegeneration. By standardizing multiple techniques and identifying their common overlap, a clearer picture of the soluble neuropathological aggresome can be constructed and used as a baseline for studying human disease and aging.
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Affiliation(s)
- Gregory-Neal Gomes
- Department of Pathology, Yale School of Medicine, New Haven, CT, 06520, USA
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Zachary A. Levine
- Department of Pathology, Yale School of Medicine, New Haven, CT, 06520, USA
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06511, USA
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9
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Rationally designed peptide-based inhibitor of Aβ42 fibril formation and toxicity: a potential therapeutic strategy for Alzheimer's disease. Biochem J 2020; 477:2039-2054. [PMID: 32427336 PMCID: PMC7293109 DOI: 10.1042/bcj20200290] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/12/2020] [Accepted: 05/18/2020] [Indexed: 12/22/2022]
Abstract
Amyloid beta peptide (Aβ42) aggregation in the brain is thought to be responsible for the onset of Alzheimer's disease, an insidious condition without an effective treatment or cure. Hence, a strategy to prevent aggregation and subsequent toxicity is crucial. Bio-inspired peptide-based molecules are ideal candidates for the inhibition of Aβ42 aggregation, and are currently deemed to be a promising option for drug design. In this study, a hexapeptide containing a self-recognition component unique to Aβ42 was designed to mimic the β-strand hydrophobic core region of the Aβ peptide. The peptide is comprised exclusively of D-amino acids to enhance specificity towards Aβ42, in conjunction with a C-terminal disruption element to block the recruitment of Aβ42 monomers on to fibrils. The peptide was rationally designed to exploit the synergy between the recognition and disruption components, and incorporates features such as hydrophobicity, β-sheet propensity, and charge, that all play a critical role in the aggregation process. Fluorescence assays, native ion-mobility mass spectrometry (IM-MS) and cell viability assays were used to demonstrate that the peptide interacts with Aβ42 monomers and oligomers with high specificity, leading to almost complete inhibition of fibril formation, with essentially no cytotoxic effects. These data define the peptide-based inhibitor as a potentially potent anti-amyloid drug candidate for this hitherto incurable disease.
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10
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Noda K, Tachi Y, Okamoto Y. Structural Characteristics of Monomeric Aβ42 on Fibril in the Early Stage of Secondary Nucleation Process. ACS Chem Neurosci 2020; 11:2989-2998. [PMID: 32794732 DOI: 10.1021/acschemneuro.0c00163] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Amyloid-β (Aβ) aggregates are believed to be one of the main causes of Alzheimer's disease. Aβ peptides form fibrils having cross β-sheet structures mainly through primary nucleation, secondary nucleation, and elongation. In particular, self-catalyzed secondary nucleation is of great interest. Here, we investigate the adsorption of Aβ42 peptides to the Aβ42 fibril to reveal a role of adsorption as a part of secondary nucleation. We performed extensive molecular dynamics simulations based on replica exchange with solute tempering 2 (REST2) to two systems: a monomeric Aβ42 in solution and a complex of an Aβ42 peptide and Aβ42 fibril. Results of our simulations show that the Aβ42 monomer is extended on the fibril. Furthermore, we find that the hairpin structure of the Aβ42 monomer decreases but the helix structure increases by adsorption to the fibril surface. These structural changes are preferable for forming fibril-like aggregates, suggesting that the fibril surface serves as a catalyst in the secondary nucleation process. In addition, the stabilization of the helix structure of the Aβ42 monomer on the fibril indicates that the strategy of a secondary nucleation inhibitor design for Aβ40 can also be used for Aβ42.
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Affiliation(s)
- Kohei Noda
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Yuhei Tachi
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Yuko Okamoto
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
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11
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Ratha BN, Kar RK, Brender JR, Pariary R, Sahoo B, Kalita S, Bhunia A. High-resolution structure of a partially folded insulin aggregation intermediate. Proteins 2020; 88:1648-1659. [PMID: 32683793 DOI: 10.1002/prot.25983] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 06/11/2020] [Accepted: 07/12/2020] [Indexed: 01/01/2023]
Abstract
Insulin has long been served as a model for protein aggregation, both due to the importance of aggregation in the manufacture of insulin and because the structural biology of insulin has been extensively characterized. Despite intensive study, details about the initial triggers for aggregation have remained elusive at the molecular level. We show here that at acidic pH, the aggregation of insulin is likely initiated by a partially folded monomeric intermediate. High-resolution structures of the partially folded intermediate show that it is coarsely similar to the initial monomeric structure but differs in subtle details-the A chain helices on the receptor interface are more disordered and the B chain helix is displaced from the C-terminal A chain helix when compared to the stable monomer. The result of these movements is the creation of a hydrophobic cavity in the center of the protein that may serve as nucleation site for oligomer formation. Knowledge of this transition may aid in the engineering of insulin variants that retain the favorable pharamacokinetic properties of monomeric insulin but are more resistant to aggregation.
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Affiliation(s)
- Bhisma N Ratha
- Department of Biophysics, Bose Institute, Kolkata, India
| | - Rajiv K Kar
- Department of Biophysics, Bose Institute, Kolkata, India
| | - Jeffrey R Brender
- Radiation Biology Branch, National Institutes of Health, Bethesda, Maryland, USA
| | - Ranit Pariary
- Department of Biophysics, Bose Institute, Kolkata, India
| | | | - Sujan Kalita
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, India
| | - Anirban Bhunia
- Department of Biophysics, Bose Institute, Kolkata, India
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12
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Hu ZW, Au DF, Cruceta L, Vugmeyster L, Qiang W. N-Terminal Modified Aβ Variants Enable Modulations to the Structures and Cytotoxicity Levels of Wild-Type Aβ Fibrils through Cross-Seeding. ACS Chem Neurosci 2020; 11:2058-2065. [PMID: 32603584 DOI: 10.1021/acschemneuro.0c00316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Post-translational modifications (PTMs) of β-amyloid (Aβ) peptides are considered as triggering factors in sporadic Alzheimer's disease. However, studies to show the influence of pre-existing PTM-Aβ fibrils on wild-type Aβ peptides, which directly mimic the triggering scenarios, are rare. Here we show that three types of pathologically relevant PTM-Aβ variants with modifications in a particular segment (from D7 to V12) of the primary sequence lead to distinct impacts on the fibrillization of wild-type Aβ peptides. In general, the triggering effects are observed through cross-seeding between the PTM-Aβ seeds and wild-type peptides, which consequently induce modulations in the resultant wild-type fibril structures and elevations in the fibrillar cytotoxicity levels. Modifications with a similar chemical nature, such as the S8-phosphorylation and Y10-nitration, both of which introduce additional side-chain negative charges, show comparable structural-modulation and cytotoxicity-elevation effects. The results imply the biological influences of PTM-Aβ variants on the formation of amyloid deposits through cross-seeded fibrillization.
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Affiliation(s)
- Zhi-Wen Hu
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, New York 13902, United States
| | - Dan Fai Au
- Department of Chemistry, University of Colorado at Denver, Denver, Colorado 80204, United States
| | - Letticia Cruceta
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, New York 13902, United States
| | - Liliya Vugmeyster
- Department of Chemistry, University of Colorado at Denver, Denver, Colorado 80204, United States
| | - Wei Qiang
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, New York 13902, United States
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13
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Penke B, Szűcs M, Bogár F. Oligomerization and Conformational Change Turn Monomeric β-Amyloid and Tau Proteins Toxic: Their Role in Alzheimer's Pathogenesis. Molecules 2020; 25:molecules25071659. [PMID: 32260279 PMCID: PMC7180792 DOI: 10.3390/molecules25071659] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/29/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
The structural polymorphism and the physiological and pathophysiological roles of two important proteins, β-amyloid (Aβ) and tau, that play a key role in Alzheimer's disease (AD) are reviewed. Recent results demonstrate that monomeric Aβ has important physiological functions. Toxic oligomeric Aβ assemblies (AβOs) may play a decisive role in AD pathogenesis. The polymorph fibrillar Aβ (fAβ) form has a very ordered cross-β structure and is assumed to be non-toxic. Tau monomers also have several important physiological actions; however, their oligomerization leads to toxic oligomers (TauOs). Further polymerization results in probably non-toxic fibrillar structures, among others neurofibrillary tangles (NFTs). Their structure was determined by cryo-electron microscopy at atomic level. Both AβOs and TauOs may initiate neurodegenerative processes, and their interactions and crosstalk determine the pathophysiological changes in AD. TauOs (perhaps also AβO) have prionoid character, and they may be responsible for cell-to-cell spreading of the disease. Both extra- and intracellular AβOs and TauOs (and not the previously hypothesized amyloid plaques and NFTs) may represent the novel targets of AD drug research.
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Affiliation(s)
- Botond Penke
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (M.S.); (F.B.)
- Correspondence:
| | - Mária Szűcs
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (M.S.); (F.B.)
| | - Ferenc Bogár
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (M.S.); (F.B.)
- MTA-SZTE Biomimetic Systems Research Group, University of Szeged, H-6720 Szeged, Hungary
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14
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A new Zn(II)-coordination polymer based on m-terphenyl pentacarboxylic acid ligand for photocatalytic methylene blue degradation and protective effect against Alzheimer’s disease by reducing the inflammatory response and oxidative stress in the nerve cells. ARAB J CHEM 2020. [DOI: 10.1016/j.arabjc.2020.02.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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15
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Wille H, Dorosh L, Amidian S, Schmitt-Ulms G, Stepanova M. Combining molecular dynamics simulations and experimental analyses in protein misfolding. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2020; 118:33-110. [PMID: 31928730 DOI: 10.1016/bs.apcsb.2019.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The fold of a protein determines its function and its misfolding can result in loss-of-function defects. In addition, for certain proteins their misfolding can lead to gain-of-function toxicities resulting in protein misfolding diseases such as Alzheimer's, Parkinson's, or the prion diseases. In all of these diseases one or more proteins misfold and aggregate into disease-specific assemblies, often in the form of fibrillar amyloid deposits. Most, if not all, protein misfolding diseases share a fundamental molecular mechanism that governs the misfolding and subsequent aggregation. A wide variety of experimental methods have contributed to our knowledge about misfolded protein aggregates, some of which are briefly described in this review. The misfolding mechanism itself is difficult to investigate, as the necessary timescale and resolution of the misfolding events often lie outside of the observable parameter space. Molecular dynamics simulations fill this gap by virtue of their intrinsic, molecular perspective and the step-by-step iterative process that forms the basis of the simulations. This review focuses on molecular dynamics simulations and how they combine with experimental analyses to provide detailed insights into protein misfolding and the ensuing diseases.
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Affiliation(s)
- Holger Wille
- Department of Biochemistry, University of Alberta, Edmonton, Canada; Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Canada; Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Lyudmyla Dorosh
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada
| | - Sara Amidian
- Department of Biochemistry, University of Alberta, Edmonton, Canada; Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Canada
| | - Gerold Schmitt-Ulms
- Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Maria Stepanova
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada
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16
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Nguyen PH, Sterpone F, Derreumaux P. Aggregation of disease-related peptides. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 170:435-460. [PMID: 32145950 DOI: 10.1016/bs.pmbts.2019.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Protein misfolding and aggregation of amyloid proteins is the fundamental cause of more than 20 diseases. Molecular mechanisms of the self-assembly and the formation of the toxic aggregates are still elusive. Computer simulations have been intensively used to study the aggregation of amyloid peptides of various amino acid lengths related to neurodegenerative diseases. We review atomistic and coarse-grained simulations of short amyloid peptides aimed at determining their transient oligomeric structures and the early and late aggregation steps.
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Affiliation(s)
- Phuong H Nguyen
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, Paris, France; Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Fabio Sterpone
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, Paris, France; Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Philippe Derreumaux
- Laboratory of Theoretical Chemistry, Ton Duc Thang University, Ho Chi Minh City, Vietnam; Faculty of Pharmacy, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
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17
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Computational studies of protein aggregation mediated by amyloid: Fibril elongation and secondary nucleation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 170:461-504. [DOI: 10.1016/bs.pmbts.2019.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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18
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Penke B, Bogár F, Paragi G, Gera J, Fülöp L. Key Peptides and Proteins in Alzheimer's Disease. Curr Protein Pept Sci 2019; 20:577-599. [PMID: 30605056 DOI: 10.2174/1389203720666190103123434] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 12/03/2018] [Accepted: 12/27/2018] [Indexed: 02/02/2023]
Abstract
Alzheimer's Disease (AD) is a form of progressive dementia involving cognitive impairment, loss of learning and memory. Different proteins (such as amyloid precursor protein (APP), β- amyloid (Aβ) and tau protein) play a key role in the initiation and progression of AD. We review the role of the most important proteins and peptides in AD pathogenesis. The structure, biosynthesis and physiological role of APP are shortly summarized. The details of trafficking and processing of APP to Aβ, the cytosolic intracellular Aβ domain (AICD) and small soluble proteins are shown, together with other amyloid-forming proteins such as tau and α-synuclein (α-syn). Hypothetic physiological functions of Aβ are summarized. The mechanism of conformational change, the formation and the role of neurotoxic amyloid oligomeric (oAβ) are shown. The fibril formation process and the co-existence of different steric structures (U-shaped and S-shaped) of Aβ monomers in mature fibrils are demonstrated. We summarize the known pathogenic and non-pathogenic mutations and show the toxic interactions of Aβ species after binding to cellular receptors. Tau phosphorylation, fibrillation, the molecular structure of tau filaments and their toxic effect on microtubules are shown. Development of Aβ and tau imaging in AD brain and CSF as well as blood biomarkers is shortly summarized. The most probable pathomechanisms of AD including the toxic effects of oAβ and tau; the three (biochemical, cellular and clinical) phases of AD are shown. Finally, the last section summarizes the present state of Aβ- and tau-directed therapies and future directions of AD research and drug development.
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Affiliation(s)
- Botond Penke
- Department of Medical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dom square 8, Szeged, H-6720, Hungary
| | - Ferenc Bogár
- Department of Medical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dom square 8, Szeged, H-6720, Hungary.,MTA-SZTE Biomimetic Systems Research Group, University of Szeged, H-6720 Szeged, Dom square 8, Hungary
| | - Gábor Paragi
- MTA-SZTE Biomimetic Systems Research Group, University of Szeged, H-6720 Szeged, Dom square 8, Hungary.,Institute of Physics, University of Pécs, H-7624 Pecs, Ifjusag utja 6, Hungary
| | - János Gera
- Department of Medical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dom square 8, Szeged, H-6720, Hungary
| | - Lívia Fülöp
- Department of Medical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dom square 8, Szeged, H-6720, Hungary
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19
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Cline EN, Bicca MA, Viola KL, Klein WL. The Amyloid-β Oligomer Hypothesis: Beginning of the Third Decade. J Alzheimers Dis 2019; 64:S567-S610. [PMID: 29843241 PMCID: PMC6004937 DOI: 10.3233/jad-179941] [Citation(s) in RCA: 520] [Impact Index Per Article: 104.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The amyloid-β oligomer (AβO) hypothesis was introduced in 1998. It proposed that the brain damage leading to Alzheimer’s disease (AD) was instigated by soluble, ligand-like AβOs. This hypothesis was based on the discovery that fibril-free synthetic preparations of AβOs were potent CNS neurotoxins that rapidly inhibited long-term potentiation and, with time, caused selective nerve cell death (Lambert et al., 1998). The mechanism was attributed to disrupted signaling involving the tyrosine-protein kinase Fyn, mediated by an unknown toxin receptor. Over 4,000 articles concerning AβOs have been published since then, including more than 400 reviews. AβOs have been shown to accumulate in an AD-dependent manner in human and animal model brain tissue and, experimentally, to impair learning and memory and instigate major facets of AD neuropathology, including tau pathology, synapse deterioration and loss, inflammation, and oxidative damage. As reviewed by Hayden and Teplow in 2013, the AβO hypothesis “has all but supplanted the amyloid cascade.” Despite the emerging understanding of the role played by AβOs in AD pathogenesis, AβOs have not yet received the clinical attention given to amyloid plaques, which have been at the core of major attempts at therapeutics and diagnostics but are no longer regarded as the most pathogenic form of Aβ. However, if the momentum of AβO research continues, particularly efforts to elucidate key aspects of structure, a clear path to a successful disease modifying therapy can be envisioned. Ensuring that lessons learned from recent, late-stage clinical failures are applied appropriately throughout therapeutic development will further enable the likelihood of a successful therapy in the near-term.
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Affiliation(s)
- Erika N Cline
- Department of Neurobiology, Cognitive Neurology and Alzheimer's Disease Center, International Institute for Nanotechnology, and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - Maíra Assunção Bicca
- Department of Neurobiology, Cognitive Neurology and Alzheimer's Disease Center, International Institute for Nanotechnology, and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - Kirsten L Viola
- Department of Neurobiology, Cognitive Neurology and Alzheimer's Disease Center, International Institute for Nanotechnology, and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - William L Klein
- Department of Neurobiology, Cognitive Neurology and Alzheimer's Disease Center, International Institute for Nanotechnology, and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
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20
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Bunce SJ, Wang Y, Stewart KL, Ashcroft AE, Radford SE, Hall CK, Wilson AJ. Molecular insights into the surface-catalyzed secondary nucleation of amyloid-β 40 (Aβ 40) by the peptide fragment Aβ 16-22. SCIENCE ADVANCES 2019; 5:eaav8216. [PMID: 31245536 PMCID: PMC6588359 DOI: 10.1126/sciadv.aav8216] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 05/15/2019] [Indexed: 05/15/2023]
Abstract
Understanding the structural mechanism by which proteins and peptides aggregate is crucial, given the role of fibrillar aggregates in debilitating amyloid diseases and bioinspired materials. Yet, this is a major challenge as the assembly involves multiple heterogeneous and transient intermediates. Here, we analyze the co-aggregation of Aβ40 and Aβ16-22, two widely studied peptide fragments of Aβ42 implicated in Alzheimer's disease. We demonstrate that Aβ16-22 increases the aggregation rate of Aβ40 through a surface-catalyzed secondary nucleation mechanism. Discontinuous molecular dynamics simulations allowed aggregation to be tracked from the initial random coil monomer to the catalysis of nucleation on the fibril surface. Together, the results provide insight into how dynamic interactions between Aβ40 monomers/oligomers on the surface of preformed Aβ16-22 fibrils nucleate Aβ40 amyloid assembly. This new understanding may facilitate development of surfaces designed to enhance or suppress secondary nucleation and hence to control the rates and products of fibril assembly.
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Affiliation(s)
- Samuel J. Bunce
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Yiming Wang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, USA
| | - Katie L. Stewart
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Alison E. Ashcroft
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Sheena E. Radford
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
- Corresponding author. (S.E.R.); (C.K.H.); (A.J.W.)
| | - Carol K. Hall
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, USA
- Corresponding author. (S.E.R.); (C.K.H.); (A.J.W.)
| | - Andrew J. Wilson
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
- Corresponding author. (S.E.R.); (C.K.H.); (A.J.W.)
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21
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Brender JR, Ghosh A, Kotler SA, Krishnamoorthy J, Bera S, Morris V, Sil TB, Garai K, Reif B, Bhunia A, Ramamoorthy A. Probing transient non-native states in amyloid beta fiber elongation by NMR. Chem Commun (Camb) 2019; 55:4483-4486. [PMID: 30917192 DOI: 10.1039/c9cc01067j] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Using NMR to probe transient binding of Aβ1-40 monomers to fibers, we find partially bound conformations with the highest degree of interaction near F19-K28 and a lesser degree of interaction near the C-terminus (L34-G37). This represents a shift away from the KLVFFA recognition sequence (residues 16-21) currently used for inhibitor design.
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22
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Hao X, Zheng J, Sun Y, Dong X. Seeding and Cross-Seeding Aggregations of Aβ 40 and Its N-Terminal-Truncated Peptide Aβ 11-40. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:2821-2831. [PMID: 30681866 DOI: 10.1021/acs.langmuir.8b03599] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In the amyloid plaques of Alzheimer's disease (AD) patients, a large number of N-terminal-truncated amyloid β (Aβ) peptides such as Aβ11-40 have been identified in addition to the full-length Aβ peptides. However, little is known about the roles of the N-terminal-truncated peptides in AD pathological process. Herein, seeding and cross-seeding aggregations of Aβ40 and its N-terminal-truncated Aβ11-40 were investigated in the solution and on the surfaces of chips with immobilized seeds by extensive biophysical and biological analyses. The results showed that Aβ40 and Aβ11-40 aggregates could seed both homologous and heterologous aggregations of the two monomers. However, the capability and characteristics of the seeding (homologous aggregation) and cross-seeding (heterologous aggregation) were significantly different. Aβ40 seeds showed stronger acceleration effects on the aggregations than Aβ11-40 seeds and induced β-sheet-rich fibrous aggregates of similar cytotoxicities for the two monomers. This indicates that Aβ40 and Aβ11-40 had similar aggregation pathways in the seeding and cross-seeding on Aβ40 seeds. By contrast, Aβ11-40 seeds led to different aggregation pathways of Aβ40 and Aβ11-40. Pure Aβ11-40 aggregates had higher toxicity than Aβ40 aggregates, and as seeds, Aβ11-40 seeds induced Aβ40 to form aggregates of higher cytotoxicity. However, homologous Aβ11-40 aggregates induced by Aβ11-40 seeds showed lower cytotoxicity than pure Aβ11-40 aggregates. The results suggest that Aβ11-40 plays an important role in the pathological process of AD.
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Affiliation(s)
- Xiuping Hao
- 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
| | - Jie Zheng
- Department of Chemical and Biomolecular Engineering , The University of Akron , Akron , Ohio 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
| | - Xiaoyan Dong
- 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
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23
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Abstract
The long lag times and subsequent rapid growth of Alzheimer's Aβ42 fibrils can be explained by a secondary nucleation step, in which existing fibril surfaces are able to nucleate the formation of new fibrils via an autocatalytic process. The molecular mechanism of secondary nucleation, however, is still unknown. Here we investigate the first step, namely, adsorption of the Aβ42 peptide monomers onto the fibril surface. Using long all-atom molecular simulations and an enhanced sampling scheme, we are able to generate a diverse ensemble of binding events. The resulting thermodynamics of adsorption are consistent with experiment as well as with the requirements for effective autocatalysis determined from coarse-grained simulations. We identify the key interactions stabilizing the adsorbed state, which are predominantly polar in nature, and relate them to the effects of known disease-causing mutations.
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Affiliation(s)
- Mathias M J Bellaiche
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases , National Institutes of Health , Bethesda , Maryland 20892-0520 , United States
- Department of Chemistry , University of Cambridge , Lensfield Road, Cambridge CB2 1EW , United Kingdom
| | - Robert B Best
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases , National Institutes of Health , Bethesda , Maryland 20892-0520 , United States
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24
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Carballo-Pacheco M, Ismail AE, Strodel B. On the Applicability of Force Fields To Study the Aggregation of Amyloidogenic Peptides Using Molecular Dynamics Simulations. J Chem Theory Comput 2018; 14:6063-6075. [PMID: 30336669 DOI: 10.1021/acs.jctc.8b00579] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular dynamics simulations play an essential role in understanding biomolecular processes such as protein aggregation at temporal and spatial resolutions which are not attainable by experimental methods. For a correct modeling of protein aggregation, force fields must accurately represent molecular interactions. Here, we study the effect of five different force fields on the oligomer formation of Alzheimer's Aβ16-22 peptide and two of its mutants: Aβ16-22(F19V,F20V), which does not form fibrils, and Aβ16-22(F19L) which forms fibrils faster than the wild type. We observe that while oligomer formation kinetics depends strongly on the force field, structural properties, such as the most relevant protein-protein contacts, are similar between them. The oligomer formation kinetics obtained with different force fields differ more from each other than the kinetics between aggregating and nonaggregating peptides simulated with a single force field. We discuss the difficulties in comparing atomistic simulations of amyloid oligomer formation with experimental observables.
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Affiliation(s)
- Martín Carballo-Pacheco
- Institute of Complex Systems: Structural Biochemistry (ICS-6) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany.,AICES Graduate School , RWTH Aachen University , Schinkelstraße 2 , 52062 Aachen , Germany
| | - Ahmed E Ismail
- AICES Graduate School , RWTH Aachen University , Schinkelstraße 2 , 52062 Aachen , Germany.,Aachener Verfahrenstechnik, Faculty of Mechanical Engineering , RWTH Aachen University , Schinkelstraße 2 , 52062 Aachen , Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6) , Forschungszentrum Jülich GmbH , 52425 Jülich , Germany.,Institute of Theoretical and Computational Chemistry , Heinrich Heine University Düsseldorf , Universitätstrasse 1 , 40225 Düsseldorf , Germany
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25
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Törnquist M, Michaels TCT, Sanagavarapu K, Yang X, Meisl G, Cohen SIA, Knowles TPJ, Linse S. Secondary nucleation in amyloid formation. Chem Commun (Camb) 2018; 54:8667-8684. [PMID: 29978862 DOI: 10.1039/c8cc02204f] [Citation(s) in RCA: 272] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Nucleation of new peptide and protein aggregates on the surfaces of amyloid fibrils of the same peptide or protein has emerged in the past two decades as a major pathway for both the generation of molecular species responsible for cellular toxicity and for the autocatalytic proliferation of peptide and protein aggregates. A key question in current research is the molecular mechanism and driving forces governing such processes, known as secondary nucleation. In this context, the analogies with other self-assembling systems for which monomer-dependent secondary nucleation has been studied for more than a century provide a valuable source of inspiration. Here, we present a short overview of this background and then review recent results regarding secondary nucleation of amyloid-forming peptides and proteins, focusing in particular on the amyloid β peptide (Aβ) from Alzheimer's disease, with some examples regarding α-synuclein from Parkinson's disease. Monomer-dependent secondary nucleation of Aβ was discovered using a combination of kinetic experiments, global analysis, seeding experiments and selective isotope-enrichment, which pinpoint the monomer as the origin of new aggregates in a fibril-catalyzed reaction. Insights into driving forces are gained from variations of solution conditions, temperature and peptide sequence. Selective inhibition of secondary nucleation is explored as an effective means to limit oligomer production and toxicity. We also review experiments aimed at finding interaction partners of oligomers generated by secondary nucleation in an ongoing aggregation process. At the end of this feature article we bring forward outstanding questions and testable mechanistic hypotheses regarding monomer-dependent secondary nucleation in amyloid formation.
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Affiliation(s)
- Mattias Törnquist
- Lund University, Department of Biochemistry and Structural Biology, Chemical Centre, PO Box 124, SE221 00 Lund, Sweden.
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26
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Recent Advances by In Silico and In Vitro Studies of Amyloid-β 1-42 Fibril Depicted a S-Shape Conformation. Int J Mol Sci 2018; 19:ijms19082415. [PMID: 30115846 PMCID: PMC6121414 DOI: 10.3390/ijms19082415] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 08/09/2018] [Accepted: 08/10/2018] [Indexed: 12/19/2022] Open
Abstract
The amyloid-β 1-42 (Aβ1-42) peptide is produced by proteolytic cleavage of the amyloid precursor protein (APP) by sequential reactions that are catalyzed by γ and β secretases. Aβ1-42, together with the Tau protein are two principal hallmarks of Alzheimer's disease (AD) that are related to disease genesis and progression. Aβ1-42 possesses a higher aggregation propensity, and it is able to form fibrils via nucleated fibril formation. To date, there are compounds available that prevent Aβ1-42 aggregation, but none have been successful in clinical trials, possibly because the Aβ1-42 structure and aggregation mechanisms are not thoroughly understood. New molecules have been designed, employing knowledge of the Aβ1-42 structure and are based on preventing or breaking the ionic interactions that have been proposed for formation of the Aβ1-42 fibril U-shaped structure. Recently, a new Aβ1-42 fibril S-shaped structure was reported that, together with its aggregation and catalytic properties, could be helpful in the design of new inhibitor molecules. Therefore, in silico and in vitro methods have been employed to analyze the Aβ1-42 fibril S-shaped structure and its aggregation to obtain more accurate Aβ1-42 oligomerization data for the design and evaluation of new molecules that can prevent the fibrillation process.
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27
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Jiang X, Cao Y, Han W. In Silico Study of Recognition between Aβ 40 and Aβ 40 Fibril Surfaces: An N-Terminal Helical Recognition Motif and Its Implications for Inhibitor Design. ACS Chem Neurosci 2018; 9:935-944. [PMID: 29281261 DOI: 10.1021/acschemneuro.7b00359] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The recent finding that the surface of amyloid-β (Aβ) fibril can recruit Aβ peptides and convert them into toxic oligomers has rendered fibril surfaces attractive as inhibition targets. Through extensive simulations with hybrid-resolution and all-atom models, we have investigated how Aβ1-40 recognizes its own fibril surfaces. These calculations give a ∼2.6-5.6 μM half-saturation concentration of Aβ on the surface (cf. experimental value ∼6 μM). Aβ was found to preferentially bind to region 16-24 of Aβ40 fibrils through both electrostatic and van der Waals forces. Both terminal regions of Aβ contribute significantly to binding energetics. A helical binding pose of the N-terminal region of Aβ (Aβ3-14) not seen before is highly preferred on the fibril surface. Aβ3-14 in a helical form can arrange side chains with similar properties on the same sides of the helix and maximize complementary interactions with side chain arrays characteristic of amyloid fibrils. Helix formation on a fibril surface implies a helix-mediated mechanism for Aβ oligomerization catalyzed by fibrils. We propose an Aβ3-14 analogue that can exhibit enhanced helical character and interactions with Aβ fibrils and may thus be used as a template with which to pursue potent inhibitors of Aβ-fibril interactions.
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Affiliation(s)
- Xuehan Jiang
- Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Yang Cao
- Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Wei Han
- Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
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28
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Abstract
The aggregation of the Aβ peptide (Aβ1-42) to form fibrils is a key feature of Alzheimer's disease. The mechanism is thought to be a nucleation stage followed by an elongation process. The elongation stage involves the consecutive addition of monomers to one end of the growing fibril. The aggregation process proceeds in a stop-and-go fashion and may involve off-pathway aggregates, complicating experimental and computational studies. Here we present exploration of a well-defined region in the free and potential energy landscapes for the Aβ17-42 pentamer. We find that the ideal aggregation process agrees with the previously reported dock-lock mechanism. We also analyze a large number of additional stable structures located on the multifunnel energy landscape, which constitute kinetic traps. The key contributors to the formation of such traps are misaligned strong interactions, for example the stacking of F19 and F20, as well as entropic contributions. Our results suggest that folding templates for aggregation are a necessity and that aggregation studies could employ such species to obtain a more detailed description of the process.
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Affiliation(s)
- Konstantin Röder
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , United Kingdom
| | - David J Wales
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge , CB2 1EW , United Kingdom
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29
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Weber OC, Uversky VN. How accurate are your simulations? Effects of confined aqueous volume and AMBER FF99SB and CHARMM22/CMAP force field parameters on structural ensembles of intrinsically disordered proteins: Amyloid-β 42 in water. INTRINSICALLY DISORDERED PROTEINS 2017; 5:e1377813. [PMID: 30250773 DOI: 10.1080/21690707.2017.1377813] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/04/2017] [Accepted: 09/06/2017] [Indexed: 12/14/2022]
Abstract
Amyloid-β42 (Aβ42) is an intrinsically disordered peptide intimately related to the pathogenesis of several neurodegenerative diseases. Molecular dynamics (MD) simulations are extensively utilized in the characterization of the structures and conformational dynamics of intrinsically disordered proteins (IDPs) including Aβ42, with AMBER and CHARMM parameters being commonly used in these studies. Recently, comparison of the effects of force field parameters on the Aβ42 structures has started to gain significant attention. In this study, the structures of Aβ42 are simulated using AMBER FF99SB and CHARMM22/CMAP parameters via replica exchange MD simulations utilizing a widely used clustering algorithm. These analyses show that the structural properties (extent and positioning of the elements of secondary and tertiary structure), radius of gyration values, number and position of salt bridges are extremely dependent on the chosen force field parameters notably with the usage of clustering algorithms. For example, predicted secondary structure elements, which are of the great importance for better understanding of the molecular mechanisms of neurodegenerative diseases, deviate enormously in models generated using currently available force field parameters for proteins. Based on the derived models, chemical shift values are calculated and compared to the experimentally determined data. This comparison revealed that although both force field parameters yield results in agreement with experiments, the obtained structural properties were rather different using a clustering algorithm. In other words, these results show that the predicted structures depend heavily on the force field parameters. Importantly, since none of the force field parameters currently utilized in MD studies were developed specifically taking into account the disordered nature of IDPs, these findings clearly indicate that new force field parameters have to be developed for IDPs considering their rapid flexibility and dynamics with high amplitude. Furthermore, molecular simulations of IDPs are typically conducted using one water volume. We show that the confined aqueous volume impacts the predicted structural properties of Aβ42 in water. Although up to date, confined aqueous volume effects have been ignored in the MD simulations of IDPs in water, our data indicate that these effects have to be taken into account in predicting the structural and thermodynamic properties of disordered proteins in solution.
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Affiliation(s)
- Orkid Coskuner Weber
- Department of Chemistry and Neurosciences Institute, The University of Texas at San Antonio, San Antonio, TX, USA.,Institut für Physikalische Chemie, Universität zu Köln, Köln, Germany.,Molecular Biotechnology Division, Turkisch-Deutsche Universität, Istanbul Turkey
| | - Vladimir N Uversky
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
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30
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Abstract
We present a theoretical model for the nucleation of amyloid fibrils. In our model we use helix-coil theory to describe the equilibrium between a soluble native state and an aggregation-prone unfolded state. We then extend the theory to include oligomers with β-sheet cores and calculate the free energy of these states using estimates for the energies of H-bonds, steric zipper interactions, and the conformational entropy cost of forming secondary structure. We find that states with fewer than ~10 β-strands are unstable relative to the dissociated state and three β-strands is the highest free energy state. We then use a modified version of Classical Nucleation Theory to compute the nucleation rate of fibrils from a supersaturated solution of monomers, dimers, and trimers. The nucleation rate has a non-monotonic dependence on denaturant concentration reflecting the competing effects of destabilizing the fibril and increasing the concentration of unfolded monomers. We estimate heterogeneous nucleation rates and discuss the application of our model to secondary nucleation.
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Affiliation(s)
- Lingyun Zhang
- Department of Physics, Kansas State University, Manhattan, KS 66506, USA
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jeremy D Schmit
- Department of Physics, Kansas State University, Manhattan, KS 66506, USA
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