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Wang J, Dai L, Chen S, Zhang Z, Fang X, Zhang Z. Protein-protein interactions regulating α-synuclein pathology. Trends Neurosci 2024; 47:209-226. [PMID: 38355325 DOI: 10.1016/j.tins.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/15/2023] [Accepted: 01/21/2024] [Indexed: 02/16/2024]
Abstract
Parkinson's disease (PD) is a neurodegenerative disease characterized by the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the formation of Lewy bodies (LBs). The main proteinaceous component of LBs is aggregated α-synuclein (α-syn). However, the mechanisms underlying α-syn aggregation are not yet fully understood. Converging lines of evidence indicate that, under certain pathological conditions, various proteins can interact with α-syn and regulate its aggregation. Understanding these protein-protein interactions is crucial for unraveling the molecular mechanisms contributing to PD pathogenesis. In this review we provide an overview of the current knowledge on protein-protein interactions that regulate α-syn aggregation. Additionally, we briefly summarize the methods used to investigate the influence of protein-protein interactions on α-syn aggregation and propagation.
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Affiliation(s)
- Jiannan Wang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Lijun Dai
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Sichun Chen
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Zhaohui Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Xin Fang
- Department of Neurology, the First Affiliated Hospital of Nanchang University, Nanchang 330000, China
| | - Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China; TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan 430000, China.
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Leitão ADG, Ahammad RU, Spencer B, Wu C, Masliah E, Rissman RA. Novel systemic delivery of a peptide-conjugated antisense oligonucleotide to reduce α-synuclein in a mouse model of Alzheimer's disease. Neurobiol Dis 2023; 186:106285. [PMID: 37690676 PMCID: PMC10584037 DOI: 10.1016/j.nbd.2023.106285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 08/30/2023] [Accepted: 09/05/2023] [Indexed: 09/12/2023] Open
Abstract
Neurodegenerative disorders of aging are characterized by the progressive accumulation of proteins such as α-synuclein (α-syn) and amyloid beta (Aβ). Misfolded and aggregated α-syn has been implicated in neurological disorders such as Parkinson's disease, and Dementia with Lewy Bodies, but less so in Alzheimer's Disease (AD), despite the fact that accumulation of α-syn has been confirmed in over 50% of postmortem brains neuropathologically diagnosed with AD. To date, no therapeutic strategy has effectively or consistently downregulated α-syn in AD. Here we tested the hypothesis that by using a systemically-delivered peptide (ApoB11) bound to a modified antisense oligonucleotide against α-syn (ASO-α-syn), we can downregulate α-syn expression in an AD mouse model and improve behavioral and neuropathologic phenotypes. Our results demonstrate that monthly systemic treatment with of ApoB11:ASO α-syn beginning at 6 months of age reduces expression of α-synuclein in the brains of 9-month-old AD mice. Downregulation of α-syn led to reduction in Aβ plaque burden, prevented neuronal loss and astrogliosis. Furthermore, we found that AD mice treated with ApoB11:ASO α-syn had greatly improved hippocampal and spatial memory function in comparison to their control counterparts. Collectively, our data supports the reduction of α-syn through use of systemically-delivered ApoB11:ASO α-syn as a promising future disease-modifying therapeutic for AD.
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Affiliation(s)
- André D G Leitão
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America
| | - Rijwan U Ahammad
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America
| | - Brian Spencer
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America
| | - Chengbiao Wu
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America; Alzheimer's Therapeutic Research Institute, Keck School of Medicine of the University of Southern California, San Diego, CA 92121, United States of America
| | - Eliezer Masliah
- Laboratory of Neurogenetics, National Institute of Aging, National Institute of Health, Bethesda, MD 20892, United States of America
| | - Robert A Rissman
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States of America; Alzheimer's Therapeutic Research Institute, Keck School of Medicine of the University of Southern California, San Diego, CA 92121, United States of America; VA San Diego Healthcare System, San Diego, CA 92161, United States of America.
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Leitão AD, Spencer B, Sarsoza F, Ngolab J, Amalraj J, Masliah E, Wu C, Rissman RA. Hippocampal Reduction of α-Synuclein via RNA Interference Improves Neuropathology in Alzheimer's Disease Mice. J Alzheimers Dis 2023; 95:349-361. [PMID: 37522208 PMCID: PMC10578232 DOI: 10.3233/jad-230232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2023] [Indexed: 08/01/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) cases are often characterized by the pathological accumulation of α-synuclein (α-syn) in addition to amyloid-β (Aβ) and tau hallmarks. The role of α-syn has been extensively studied in synucleinopathy disorders, but less so in AD. Recent studies have shown that α-syn may also play a role in AD and its downregulation may be protective against the toxic effects of Aβ accumulation. OBJECTIVE We hypothesized that selectively knocking down α-syn via RNA interference improves the neuropathological and biochemical findings in AD mice. METHODS Here we used amyloid precursor protein transgenic (APP-Tg) mice to model AD and explore pathologic and behavioral phenotypes with knockdown of α-syn using RNA interference. We selectively reduced α-syn levels by stereotaxic bilateral injection of either LV-shRNA α-syn or LV-shRNA-luc (control) into the hippocampus of AD mice. RESULTS We found that downregulation of α-syn results in significant reduction in the number of Aβ plaques. In addition, mice treated with LV-shRNA α-syn had amelioration of abnormal microglial activation (Iba1) and astrocytosis (GFAP) phenotypes in AD mice. CONCLUSION Our data suggests a novel link between Aβ and α-syn pathology as well as a new therapeutic angle for targeting AD.
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Affiliation(s)
- André D.G. Leitão
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Brian Spencer
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Floyd Sarsoza
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- VA San Diego Healthcare System, La Jolla, CA, USA
| | - Jennifer Ngolab
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Jessica Amalraj
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | | | - Chengbiao Wu
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Robert A. Rissman
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
- Department of Physiology and Neuroscience, Alzheimer’s Therapeutic Research Institute of the Keck School of Medicine of the University of Southern California, San Diego, CA, USA
- VA San Diego Healthcare System, La Jolla, CA, USA
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4
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Chau E, Kim JR. α-synuclein-assisted oligomerization of β-amyloid (1-42). Arch Biochem Biophys 2022; 717:109120. [PMID: 35041853 PMCID: PMC8818042 DOI: 10.1016/j.abb.2022.109120] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/24/2021] [Accepted: 01/12/2022] [Indexed: 11/02/2022]
Abstract
Alzheimer's disease (AD) and Parkinson's disease (PD) are the two most common neurodegenerative disorders, characterized by aggregation of amyloid polypeptides, β-amyloid (Aβ) and α-synuclein (αS), respectively. Aβ and αS follow similar aggregation pathways, starting from monomers, to soluble toxic oligomeric assemblies, and to insoluble fibrils. Various studies have suggested overlaps in the pathologies of AD and PD, and have shown Aβ-αS interactions. Unfortunately, whether these protein-protein interactions lead to self- and co-assembly of Aβ and αS into oligomers - a potentially toxic synergistic mechanism - is poorly understood. Among the various Aβ isoforms, interactions of Aβ containing 42 amino acids (Aβ (1-42), referred to as Aβ42) with αS are of most direct relevance due to the high aggregation propensity and the strong toxic effect of this Aβ isoform. In this study, we carefully determined molecular consequences of interactions between Aβ42 and αS in their respective monomeric, oligomeric, and fibrillar forms using a comprehensive set of experimental tools. We show that the three αS conformers, namely, monomers, oligomers and fibrils interfered with fibrillization of Aβ42. Specifically, αS monomers and oligomers promoted oligomerization and stabilization of soluble Aβ42, possibly via direct binding or co-assembly, while αS fibrils hindered soluble Aβ42 species from converting into insoluble aggregates by the formation of large oligomers. We also provide evidence that the interactions with αS were mediated by various parts of Aβ42, depending on Aβ42 and αS conformers. Furthermore, we compared similarities and dissimilarities between Aβ42-αS and Aβ40-αS interactions. Overall, the present study provides a comprehensive depiction of the molecular interplay between Aβ42 and αS, providing insight into its synergistic toxic mechanism.
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Affiliation(s)
- Edward Chau
- Department of Chemical and Biomolecular Engineering, New York University, 6 MetroTech Center, Brooklyn, NY, 11201, USA
| | - Jin Ryoun Kim
- Department of Chemical and Biomolecular Engineering, New York University, 6 MetroTech Center, Brooklyn, NY, 11201, USA.
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Kargar F, Emadi S, Fazli H. Dimerization of Aβ40 inside dipalmitoylphosphatidylcholine bilayer and its effect on bilayer integrity: Atomistic simulation at three temperatures. Proteins 2020; 88:1540-1552. [PMID: 32557766 DOI: 10.1002/prot.25972] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 04/28/2020] [Accepted: 06/07/2020] [Indexed: 11/10/2022]
Abstract
Amyloid-beta (Aβ) protein is related to Alzheimer disease (AD), and various experiments have shown that oligomers as small as dimers are cytotoxic. Recent studies have concluded that interactions of Aβ with neuronal cell membranes lead to disruption of membrane integrity and toxicity and they play a key role in the development of AD. Molecular dynamics (MD) simulations have been used to investigate Aβ in aqueous solution and membranes. We have previously studied monomeric Aβ40 embedded in dipalmitoylphosphatidylcholine (DPPC) membrane using MD simulations. Here, we explore interactions of two Aβ40 peptides in DPPC bilayer and its consequences on dimer distribution in a lipid bilayer and on the secondary structure of the peptides. We explored that N-terminals played an important role in dimeric Aβ peptide aggregations and Aβ-bilayer interactions, while C-terminals bound peptides to bilayer like anchors. We did not observe exiting of peptides in our simulations although we observed insertion of peptides into the core of bilayer in some of our simulations. So it seems that the presence of Aβ on membrane surface increases its aggregation rate, and as diffusion occurs in two dimensions, it can increase the probability of interpeptide interactions. We found that dimeric Aβ, like monomeric one, had the ability to cause structural destabilization of DPPC membrane, which in turn might ultimately lead to cell death in an in vivo system. This information could have important implications for understanding the affinity of Aβ oligomers (here dimer) for membranes and the mechanism of Aβ oligomer toxicity in AD.
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Affiliation(s)
- Faezeh Kargar
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
| | - Saeed Emadi
- Department of Biological Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
| | - Hossein Fazli
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran.,Department of Biological Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
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6
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Saravanan KM, Zhang H, Zhang H, Xi W, Wei Y. On the Conformational Dynamics of β-Amyloid Forming Peptides: A Computational Perspective. Front Bioeng Biotechnol 2020; 8:532. [PMID: 32656188 PMCID: PMC7325929 DOI: 10.3389/fbioe.2020.00532] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 05/04/2020] [Indexed: 12/12/2022] Open
Abstract
Understanding the conformational dynamics of proteins and peptides involved in important functions is still a difficult task in computational structural biology. Because such conformational transitions in β-amyloid (Aβ) forming peptides play a crucial role in many neurological disorders, researchers from different scientific fields have been trying to address issues related to the folding of Aβ forming peptides together. Many theoretical models have been proposed in the recent years for studying Aβ peptides using mathematical, physicochemical, and molecular dynamics simulation, and machine learning approaches. In this article, we have comprehensively reviewed the developmental advances in the theoretical models for Aβ peptide folding and interactions, particularly in the context of neurological disorders. Furthermore, we have extensively reviewed the advances in molecular dynamics simulation as a tool used for studying the conversions between polymorphic amyloid forms and applications of using machine learning approaches in predicting Aβ peptides and aggregation-prone regions in proteins. We have also provided details on the theoretical advances in the study of Aβ peptides, which would enhance our understanding of these peptides at the molecular level and eventually lead to the development of targeted therapies for certain acute neurological disorders such as Alzheimer's disease in the future.
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Affiliation(s)
| | | | | | - Wenhui Xi
- Center for High Performance Computing, Joint Engineering Research Center for Health Big Data Intelligent Analysis Technology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Yanjie Wei
- Center for High Performance Computing, Joint Engineering Research Center for Health Big Data Intelligent Analysis Technology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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7
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Saranya V, Mary PV, Vijayakumar S, Shankar R. The hazardous effects of the environmental toxic gases on amyloid beta-peptide aggregation: A theoretical perspective. Biophys Chem 2020; 263:106394. [PMID: 32480019 DOI: 10.1016/j.bpc.2020.106394] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/12/2020] [Accepted: 05/12/2020] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is one of the leading causes of dementia in elderly people. It has been well documented that the exposure to environmental toxins such as CO, CO2, SO2 and NO2 that are present in the air is considered as a hallmark for the progression of Alzheimer's disease. However, their actual mechanism by which environmental toxin triggers the aggregation of Aβ42 peptide at the molecular and atomic levels remain unknown. In this study, molecular dynamics simulation was carried out to study the aggregation mechanism of the Aβ42 peptide due to its interaction of toxic gas (CO, CO2, SO2 and NO2). During the 400 ns simulation, all the Aβ42 interacted toxic gas (CO, CO2, SO2, and NO2) complexes have smaller Root Mean Square Deviation values when compared to the Aβ42 peptide, which shows that the interaction of toxic gases (CO, CO2, SO2, and NO2) would increase the Aβ42 peptide structural stability. The radius of gyration analysis also supports that Aβ42 interacted CO2 and SO2 complexes have the minimum value in the range of 0.95 nm and 1.5 nm. It is accounted that the Aβ42 interacted CO2 and SO2 complexes have a greater compact structure in comparison to Aβ42 interacted CO and NO2 complexes. Furthermore, all the Aβ42 interacted toxic gas (CO, CO2, SO2, and NO2) complexes exhibited an enhanced secondary structural probability for coil and turn regions with a reduced α-helix probability, which indicates that the interaction of toxic gases may enhance the toxicity and aggregation of Aβ42.
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Affiliation(s)
- Vasudevan Saranya
- Molecular Simulation Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046, India
| | - Pitchumani Violet Mary
- Department of Physics, Sri Shakthi Institute of Engineering and Technology, Coimbatore 641 062, India
| | | | - Ramasamy Shankar
- Molecular Simulation Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046, India.
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8
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Candreva J, Chau E, Rice ME, Kim JR. Interactions between Soluble Species of β-Amyloid and α-Synuclein Promote Oligomerization while Inhibiting Fibrillization. Biochemistry 2019; 59:425-435. [PMID: 31854188 DOI: 10.1021/acs.biochem.9b00655] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aggregations of β-amyloid (Aβ) and α-synuclein (αS) into oligomeric and fibrillar assemblies are the pathological hallmarks of Alzheimer's and Parkinson's diseases, respectively. Although Aβ and αS affect different regions of the brain and are separated at the cellular level, there is evidence of their eventual interaction in the pathology of both disorders. Characterization of interactions of Aβ and αS at various stages of their aggregation pathways could reveal mechanisms and therapeutic targets for the prevention and cure of these neurodegenerative diseases. In this study, we comprehensively examined the interactions and their molecular manifestations using an array of characterization tools. We show for the first time that αS monomers and oligomers, but not αS fibrils, inhibit Aβ fibrillization while promoting oligomerization of Aβ monomers and stabilizing preformed Aβ oligomers via coassembly, as judged by Thioflavin T fluorescence, transmission electron microscopy, and SDS- and native-PAGE with fluorescently labeled peptides/proteins. In contrast, soluble Aβ species, such as monomers and oligomers, aggregate into fibrils, when incubated alone under the otherwise same condition. Our study provides evidence that the interactions with αS soluble species, responsible for the effects, are mediated primarily by the C-terminus of Aβ, when judged by competitive immunoassays using antibodies recognizing various fragments of Aβ. We also show that the C-terminus of Aβ is a primary site for its interaction with αS fibrils. Collectively, these data demonstrate aggregation state-specific interactions between αS and Aβ and offer insight into a molecular basis of synergistic biological effects between the two polypeptides.
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Affiliation(s)
- Jason Candreva
- Department of Chemical and Biomolecular Engineering , New York University , 6 MetroTech Center , Brooklyn , New York 11201 , United States
| | - Edward Chau
- Department of Chemical and Biomolecular Engineering , New York University , 6 MetroTech Center , Brooklyn , New York 11201 , United States
| | - Margaret E Rice
- Departments of Neurosurgery, and Neuroscience and Physiology , New York University School of Medicine , New York , New York 10016 , United States
| | - Jin Ryoun Kim
- Department of Chemical and Biomolecular Engineering , New York University , 6 MetroTech Center , Brooklyn , New York 11201 , United States
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9
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Mandler M, Rockenstein E, Overk C, Mante M, Florio J, Adame A, Kim C, Santic R, Schneeberger A, Mattner F, Schmidhuber S, Galabova G, Spencer B, Masliah E, Rissman RA. Effects of single and combined immunotherapy approach targeting amyloid β protein and α-synuclein in a dementia with Lewy bodies-like model. Alzheimers Dement 2019; 15:1133-1148. [PMID: 31378574 DOI: 10.1016/j.jalz.2019.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/22/2019] [Accepted: 02/25/2019] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Immunotherapeutic approaches targeting amyloid β (Aβ) protein and tau in Alzheimer's disease and α-synuclein (α-syn) in Parkinson's disease are being developed for treating dementia with Lewy bodies. However, it is unknown if single or combined immunotherapies targeting Aβ and/or α-syn may be effective. METHODS Amyloid precursor protein/α-syn tg mice were immunized with AFFITOPEs® (AFF) peptides specific to Aβ (AD02) or α-syn (PD-AFF1) and the combination. RESULTS AD02 more effectively reduced Aβ and pTau burden; however, the combination exhibited some additive effects. Both AD02 and PD-AFF1 effectively reduced α-syn, ameliorated degeneration of pyramidal neurons, and reduced neuroinflammation. PD-AFF1 more effectively ameliorated cholinergic and dopaminergic fiber loss; the combined immunization displayed additive effects. AD02 more effectively improved buried pellet test behavior, whereas PD-AFF1 more effectively improved horizontal beam test; the combined immunization displayed additive effects. DISCUSSION Specific active immunotherapy targeting Aβ and/or α-syn may be of potential interest for the treatment of dementia with Lewy bodies.
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Affiliation(s)
| | - Edward Rockenstein
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Cassia Overk
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Michael Mante
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Jazmin Florio
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Anthony Adame
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Changyoun Kim
- Division of Neuroscience and Laboratory of Neurogenetics, National Institute on Aging, NIH, Bethesda, MD, USA
| | | | | | | | | | | | - Brian Spencer
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Eliezer Masliah
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; Division of Neuroscience and Laboratory of Neurogenetics, National Institute on Aging, NIH, Bethesda, MD, USA; Department of Pathology, University of California, San Diego, La Jolla, CA, USA
| | - Robert A Rissman
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; VA San Diego Healthcare System, La Jolla, CA, USA.
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Sivanesam K, Andersen N. Pre-structured hydrophobic peptide β-strands: A universal amyloid trap? Arch Biochem Biophys 2019; 664:51-61. [PMID: 30707943 PMCID: PMC7094768 DOI: 10.1016/j.abb.2019.01.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 01/28/2019] [Accepted: 01/28/2019] [Indexed: 01/21/2023]
Abstract
Amyloid fibril formation has long been studied because of the variety of proteins that are capable of adopting this structure despite sharing little sequence homology. This makes amyloid fibrils a challenging focus for inhibition studies because the peptides and proteins that form amyloid fibrils cannot be targeted based on a sequence motif. Most peptide inhibitors that target specific amyloidogenic proteins rely heavily on sequence recognition to ensure that the inhibitory peptide is able to bind its target. This approach is limited to targeting one amyloidogenic protein at a time. However, there is increasing evidence of cross-reactivity between amyloid-forming polypeptides. It has therefore become more useful to study the similarities between these proteins that goes beyond their sequence homology. Indeed, the observation that amyloidogenic proteins adopt similar secondary structures along the pathway to fibril formation opens the way to an interesting investigation: the development of inhibitors that could be universal amyloid traps. The review below will analyze two specific amyloidogenic proteins, α-synuclein and human amylin, and introduce a small number of peptides that have been shown to be capable of inhibiting the amyloidogenesis of both of these very dissimilar polypeptides. Some of the inhibitory peptide motifs may indeed, be applicable to Aβ and other amyloidogenic systems.
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11
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Semenyuk P, Muronetz V. Protein Interaction with Charged Macromolecules: From Model Polymers to Unfolded Proteins and Post-Translational Modifications. Int J Mol Sci 2019; 20:E1252. [PMID: 30871103 PMCID: PMC6429204 DOI: 10.3390/ijms20051252] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/05/2019] [Accepted: 03/07/2019] [Indexed: 12/18/2022] Open
Abstract
Interaction of proteins with charged macromolecules is involved in many processes in cells. Firstly, there are many naturally occurred charged polymers such as DNA and RNA, polyphosphates, sulfated glycosaminoglycans, etc., as well as pronouncedly charged proteins such as histones or actin. Electrostatic interactions are also important for "generic" proteins, which are not generally considered as polyanions or polycations. Finally, protein behavior can be altered due to post-translational modifications such as phosphorylation, sulfation, and glycation, which change a local charge of the protein region. Herein we review molecular modeling for the investigation of such interactions, from model polyanions and polycations to unfolded proteins. We will show that electrostatic interactions are ubiquitous, and molecular dynamics simulations provide an outstanding opportunity to look inside binding and reveal the contribution of electrostatic interactions. Since a molecular dynamics simulation is only a model, we will comprehensively consider its relationship with the experimental data.
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Affiliation(s)
- Pavel Semenyuk
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia.
| | - Vladimir Muronetz
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia.
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119234 Moscow, Russia.
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12
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Herrera-Zúñiga LD, Millán-Pacheco C, Viniegra-González G, Villegas E, Arregui L, Rojo-Domínguez A. Molecular dynamics on laccase from Trametes versicolor to examine thermal stability induced by salt bridges. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2018.10.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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13
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Iljina M, Dear AJ, Garcia GA, De S, Tosatto L, Flagmeier P, Whiten DR, Michaels TCT, Frenkel D, Dobson CM, Knowles TPJ, Klenerman D. Quantifying Co-Oligomer Formation by α-Synuclein. ACS NANO 2018; 12:10855-10866. [PMID: 30371053 PMCID: PMC6262461 DOI: 10.1021/acsnano.8b03575] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Small oligomers of the protein α-synuclein (αS) are highly cytotoxic species associated with Parkinson's disease (PD). In addition, αS can form co-aggregates with its mutational variants and with other proteins such as amyloid-β (Aβ) and tau, which are implicated in Alzheimer's disease. The processes of self-oligomerization and co-oligomerization of αS are, however, challenging to study quantitatively. Here, we have utilized single-molecule techniques to measure the equilibrium populations of oligomers formed in vitro by mixtures of wild-type αS with its mutational variants and with Aβ40, Aβ42, and a fragment of tau. Using a statistical mechanical model, we find that co-oligomer formation is generally more favorable than self-oligomer formation at equilibrium. Furthermore, self-oligomers more potently disrupt lipid membranes than do co-oligomers. However, this difference is sometimes outweighed by the greater formation propensity of co-oligomers when multiple proteins coexist. Our results suggest that co-oligomer formation may be important in PD and related neurodegenerative diseases.
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Affiliation(s)
- Marija Iljina
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Alexander J. Dear
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
- Department
of Chemistry, Centre for Misfolding Diseases, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Gonzalo A. Garcia
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Suman De
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Laura Tosatto
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Patrick Flagmeier
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
- Department
of Chemistry, Centre for Misfolding Diseases, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Daniel R. Whiten
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Thomas C. T. Michaels
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Daan Frenkel
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Christopher M. Dobson
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
- Department
of Chemistry, Centre for Misfolding Diseases, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Tuomas P. J. Knowles
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
- Department
of Chemistry, Centre for Misfolding Diseases, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
- E-mail:
| | - David Klenerman
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
- UK
Dementia Research Institute, University of Cambridge, Cambridge CB2 0XY, United Kingdom
- E-mail:
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14
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Jana AK, Batkulwar KB, Kulkarni MJ, Sengupta N. Glycation induces conformational changes in the amyloid-β peptide and enhances its aggregation propensity: molecular insights. Phys Chem Chem Phys 2018; 18:31446-31458. [PMID: 27827482 DOI: 10.1039/c6cp05041g] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The cytotoxicity of the amyloid beta (Aβ) peptide, implicated in the pathogenesis of Alzheimer's disease (AD), can be enhanced by its post-translational glycation, a series of non-enzymatic reactions with reducing sugars and reactive dicarbonyls. However, little is known about the underlying mechanisms that potentially enhance the cytotoxicity of the advanced glycation modified Aβ. In this work, fully atomistic molecular dynamics (MD) simulations are exploited to obtain direct molecular insights into the process of early Aβ self-assembly in the presence and absence of glycated lysine residues. Analyses of data exceeding cumulative timescales of 1 microsecond for each system reveal that glycation results in a stronger enthalpy of association between Aβ monomers and lower conformational entropy, in addition to a sharp overall increase in the beta-sheet content. Further analyses reveal that the enhanced interactions originate, in large part, due to markedly stronger, as well as new, inter-monomer salt bridging propensities in the glycated variety. Interestingly, these conformational and energetic effects are broadly reflected in preformed protofibrillar forms of Aβ small oligomers modified with glycation. Our combined results imply that glycation consolidates Aβ self-assembly regardless of its point of occurrence in the pathway. They provide a basis for further mechanistic studies and therapeutic endeavors that could potentially result in novel ways of combating AGE related AD progression.
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Affiliation(s)
- Asis K Jana
- Physical Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India and Academy of Scientific and Innovative Research (AcSIR), New Delhi, India
| | - Kedar B Batkulwar
- Academy of Scientific and Innovative Research (AcSIR), New Delhi, India and Biochemical Sciences Division, CSIR-National Chemical Laboratory, Pune 411008, India.
| | - Mahesh J Kulkarni
- Academy of Scientific and Innovative Research (AcSIR), New Delhi, India and Biochemical Sciences Division, CSIR-National Chemical Laboratory, Pune 411008, India.
| | - Neelanjana Sengupta
- Dept. of Biological Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741 246, W. Bengal, India.
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15
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Coskuner-Weber O, Uversky VN. Insights into the Molecular Mechanisms of Alzheimer's and Parkinson's Diseases with Molecular Simulations: Understanding the Roles of Artificial and Pathological Missense Mutations in Intrinsically Disordered Proteins Related to Pathology. Int J Mol Sci 2018; 19:E336. [PMID: 29364151 PMCID: PMC5855558 DOI: 10.3390/ijms19020336] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 01/14/2018] [Accepted: 01/16/2018] [Indexed: 12/18/2022] Open
Abstract
Amyloid-β and α-synuclein are intrinsically disordered proteins (IDPs), which are at the center of Alzheimer's and Parkinson's disease pathologies, respectively. These IDPs are extremely flexible and do not adopt stable structures. Furthermore, both amyloid-β and α-synuclein can form toxic oligomers, amyloid fibrils and other type of aggregates in Alzheimer's and Parkinson's diseases. Experimentalists face challenges in investigating the structures and thermodynamic properties of these IDPs in their monomeric and oligomeric forms due to the rapid conformational changes, fast aggregation processes and strong solvent effects. Classical molecular dynamics simulations complement experiments and provide structural information at the atomic level with dynamics without facing the same experimental limitations. Artificial missense mutations are employed experimentally and computationally for providing insights into the structure-function relationships of amyloid-β and α-synuclein in relation to the pathologies of Alzheimer's and Parkinson's diseases. Furthermore, there are several natural genetic variations that play a role in the pathogenesis of familial cases of Alzheimer's and Parkinson's diseases, which are related to specific genetic defects inherited in dominant or recessive patterns. The present review summarizes the current understanding of monomeric and oligomeric forms of amyloid-β and α-synuclein, as well as the impacts of artificial and pathological missense mutations on the structural ensembles of these IDPs using molecular dynamics simulations. We also emphasize the recent investigations on residual secondary structure formation in dynamic conformational ensembles of amyloid-β and α-synuclein, such as β-structure linked to the oligomerization and fibrillation mechanisms related to the pathologies of Alzheimer's and Parkinson's diseases. This information represents an important foundation for the successful and efficient drug design studies.
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Affiliation(s)
- Orkid Coskuner-Weber
- Türkisch-Deutsche Universität, Theoretical and Computational Biophysics Group, Molecular Biotechnology, Sahinkaya Caddesi, No. 86, Beykoz, Istanbul 34820, Turkey.
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
- Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia.
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16
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Liu X, Shi D, Zhou S, Liu H, Liu H, Yao X. Molecular dynamics simulations and novel drug discovery. Expert Opin Drug Discov 2017; 13:23-37. [DOI: 10.1080/17460441.2018.1403419] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Xuewei Liu
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou, China
| | - Danfeng Shi
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry, Lanzhou University, Lanzhou, China
| | | | - Hongli Liu
- 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
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17
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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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18
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Menon S, Sengupta N. Influence of Hyperglycemic Conditions on Self-Association of the Alzheimer's Amyloid β (Aβ 1-42) Peptide. ACS OMEGA 2017; 2:2134-2147. [PMID: 30023655 PMCID: PMC6044820 DOI: 10.1021/acsomega.7b00018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 05/08/2017] [Indexed: 06/08/2023]
Abstract
Clinical studies have identified a correlation between type-2 diabetes mellitus and cognitive decrements en route to the onset of Alzheimer's disease (AD). Recent studies have established that post-translational modifications of the amyloid β (Aβ) peptide occur under hyperglycemic conditions; particularly, the process of glycation exacerbates its neurotoxicity and accelerates AD progression. In view of the assertion that macromolecular crowding has an altering effect on protein self-assembly, it is crucial to characterize the effects of hyperglycemic conditions via crowding on Aβ self-assembly. Toward this purpose, fully atomistic molecular dynamics simulations were performed to study the effects of glucose crowding on Aβ dimerization, which is the smallest known neurotoxic species. The dimers formed in the glucose-crowded environment were found to have weaker associations as compared to that of those formed in water. Binding free energy calculations show that the reduced binding strength of the dimers can be mainly attributed to the overall weakening of the dispersion interactions correlated with substantial loss of interpeptide contacts in the hydrophobic patches of the Aβ units. Analysis to discern the differential solvation pattern in the glucose-crowded and pure water systems revealed that glucose molecules cluster around the protein, at a distance of 5-7 Å, which traps the water molecules in close association with the protein surface. This preferential exclusion of glucose molecules and resulting hydration of the Aβ peptides has a screening effect on the hydrophobic interactions, which in turn diminishes the binding strength of the resulting dimers. Our results imply that physical effects attributed to crowded hyperglycemic environments are incapable of solely promoting Aβ self-assembly, indicating that further mechanistic studies are required to provide insights into the self-assembly of post-translationally modified Aβ peptides, known to possess aggravated toxicity, under these conditions.
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Affiliation(s)
- Sneha Menon
- Physical
Chemistry Division, CSIR-National Chemical
Laboratory, Dr. Homi
Bhabha Road, Pune 411008, India
- Academy
of Scientific and Innovative Research (AcSIR), Training and Development Complex, CSIR Campus,
CSIR Road, Chennai 600113, India
| | - Neelanjana Sengupta
- Department
of Biological Sciences, Indian Institute
of Science Education and Research (IISER) Kolkata, Mohanpur 741246, West Bengal, India
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19
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Das P, Chacko AR, Belfort G. Alzheimer's Protective Cross-Interaction between Wild-Type and A2T Variants Alters Aβ 42 Dimer Structure. ACS Chem Neurosci 2017; 8:606-618. [PMID: 28292185 DOI: 10.1021/acschemneuro.6b00357] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Whole genome sequencing has recently revealed the protective effect of a single A2T mutation in heterozygous carriers against Alzheimer's disease (AD) and age-related cognitive decline. The impact of the protective cross-interaction between the wild-type (WT) and A2T variants on the dimer structure is therefore of high interest, as the Aβ dimers are the smallest known neurotoxic species. Toward this goal, extensive atomistic replica exchange molecular dynamics simulations of the solvated WT homo- and A2T hetero- Aβ1-42 dimers have been performed, resulting into a total of 51 μs of sampling for each system. Weakening of a set of transient, intrachain contacts formed between the central and C-terminal hydrophobic residues is observed in the heterodimeric system. The majority of the heterodimers with reduced interaction between central and C-terminal regions lack any significant secondary structure and display a weak interchain interface. Interestingly, the A2T N-terminus, particularly residue F4, is frequently engaged in tertiary and quaternary interactions with central and C-terminal hydrophobic residues in those distinct structures, leading to hydrophobic burial. This atypical involvement of the N-terminus within A2T heterodimer revealed in our simulations implies possible interference on Aβ42 aggregation and toxic oligomer formation, which is consistent with experiments. In conclusion, the present study provides detailed structural insights onto A2T Aβ42 heterodimer, which might provide molecular insights onto the AD protective effect of the A2T mutation in the heterozygous state.
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Affiliation(s)
- Payel Das
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
| | - Anita R. Chacko
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
| | - Georges Belfort
- Howard
P. Isermann Department of Chemical and Biological Engineering, and
Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, United States
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20
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Abstract
The investigation of intrinsically disordered proteins (IDPs) is a new frontier in structural and molecular biology that requires a new paradigm to connect structural disorder to function. Molecular dynamics simulations and statistical thermodynamics potentially offer ideal tools for atomic-level characterizations and thermodynamic descriptions of this fascinating class of proteins that will complement experimental studies. However, IDPs display sensitivity to inaccuracies in the underlying molecular mechanics force fields. Thus, achieving an accurate structural characterization of IDPs via simulations is a challenge. It is also daunting to perform a configuration-space integration over heterogeneous structural ensembles sampled by IDPs to extract, in particular, protein configurational entropy. In this review, we summarize recent efforts devoted to the development of force fields and the critical evaluations of their performance when applied to IDPs. We also survey recent advances in computational methods for protein configurational entropy that aim to provide a thermodynamic link between structural disorder and protein activity.
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Affiliation(s)
- Song-Ho Chong
- Department of Chemistry, Sookmyung Women's University, Yongsan-Ku, Seoul 04310, Korea;
| | - Prathit Chatterjee
- Department of Chemistry, Sookmyung Women's University, Yongsan-Ku, Seoul 04310, Korea;
| | - Sihyun Ham
- Department of Chemistry, Sookmyung Women's University, Yongsan-Ku, Seoul 04310, Korea;
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21
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Zhang Y, Hashemi M, Lv Z, Lyubchenko YL. Self-assembly of the full-length amyloid Aβ42 protein in dimers. NANOSCALE 2016; 8:18928-18937. [PMID: 27714140 PMCID: PMC5114164 DOI: 10.1039/c6nr06850b] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The self-assembly of amyloid (Aβ) proteins into nano-aggregates is a hallmark of Alzheimer's disease (AD) development, yet the mechanism of how disordered monomers assemble into aggregates remains elusive. Here, we applied long-time molecular dynamics simulations to fully characterize the assembly of Aβ42 monomers into dimers. Monomers undergo conformational changes during their interaction, but the resulting dimer structures do not resemble those found in fibril structures. To identify natural conformations of dimers among a set of simulated ones, validation approaches were developed and applied, and a subset of dimer conformations were characterized. These dimers do not contain long β-strands that are usually found in fibrils. The dimers are stabilized primarily by interactions within the central hydrophobic regions and the C-terminal regions, with a contribution from local hydrogen bonding. The dimers are dynamic, as evidenced by the existence of a set of conformations and by the quantitative analyses of the dimer dissociation process.
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Affiliation(s)
- Yuliang Zhang
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 69198, USA.
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22
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Atsmon-Raz Y, Miller Y. Non-Amyloid-β Component of Human α-Synuclein Oligomers Induces Formation of New Aβ Oligomers: Insight into the Mechanisms That Link Parkinson's and Alzheimer's Diseases. ACS Chem Neurosci 2016; 7:46-55. [PMID: 26479553 DOI: 10.1021/acschemneuro.5b00204] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Parkinson's disease (PD) is characterized by the formation of Lewy bodies (LBs), of which their major component is the non-amyloid-β component (NAC) of α-synuclein (AS). Clinical studies have identified a link between PD and Alzheimer's disease (AD), but the question of why PD patients are at risk to develop various types of dementia, such as AD, is still elusive. In vivo studies have shown that Aβ can act as a seed for NAC/AS aggregation, promoting NAC/AS aggregation and thus contributing to the etiology of PD. However, the mechanisms by which NAC/AS oligomers interact with Aβ oligomers are still elusive. This work presents the interactions between NAC oligomers and Aβ oligomers at atomic resolution by applying extensive molecular dynamics simulations for an ensemble of cross-seeded NAC-Aβ(1-42) oligomers. The main conclusions of this study are as follows: first, the cross-seeded NAC-Aβ(1-42) oligomers represent polymorphic states, yet NAC oligomers prefer to interact with Aβ(1-42) oligomers to form double-layer over single-layer conformations due to electrostatic/hydrophobic interactions; second, among the single-layer conformations, the NAC oligomers induce formation of new β-strands in Aβ(1-42) oligomers, thus leading to new Aβ oligomer structures; and third, NAC oligomers stabilize the cross-β structure of Aβ oligomers, i.e., yielding compact Aβ fibril-like structures.
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Affiliation(s)
- Yoav Atsmon-Raz
- Department of Chemistry, ‡Ilse Katz Institute for Nanoscale
Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Yifat Miller
- Department of Chemistry, ‡Ilse Katz Institute for Nanoscale
Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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23
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Menon S, Sengupta N. Perturbations in inter-domain associations may trigger the onset of pathogenic transformations in PrP(C): insights from atomistic simulations. MOLECULAR BIOSYSTEMS 2016; 11:1443-53. [PMID: 25855580 DOI: 10.1039/c4mb00689e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Conversion of the predominantly α-helical cellular prion protein (PrP(C)) to the misfolded β-sheet enriched Scrapie form (PrP(Sc)) is a critical event in prion pathogenesis. However, the conformational triggers that lead to the isoform conversion (PrP(C) to PrP(Sc)) remain obscure, and conjectures about the role of unusually hydrophilic, short helix H1 of the C-terminal globular domain in the transition are varied. Helix H1 is anchored to helix H3 via a few stabilizing polar interactions. We have employed fully atomistic molecular dynamics simulations to study the effects triggered by a minor perturbation in the network of these non-bonded interactions in PrP(C). The elimination of just one of the key H1-H3 hydrogen bonds led to a cascade of conformational changes that are consistent with those observed in partially unfolded intermediates of PrP(C), with pathogenic mutations and in low pH environments. Our analyses reveal that the perturbation results in the enhanced conformational flexibility of the protein. The resultant enhancement in the dynamics leads to overall increased solvent exposure of the hydrophobic core residues and concomitant disruption of the H1-H3 inter-domain salt bridge network. This study lends credence to the hypothesis that perturbing the cooperativity of the stabilizing interactions in the PrP(C) globular domain can critically affect its dynamics and may lead to structural transitions of pathological relevance.
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Affiliation(s)
- Sneha Menon
- Physical Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India.
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24
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Valera E, Spencer B, Masliah E. Immunotherapeutic Approaches Targeting Amyloid-β, α-Synuclein, and Tau for the Treatment of Neurodegenerative Disorders. Neurotherapeutics 2016; 13:179-89. [PMID: 26494242 PMCID: PMC4720672 DOI: 10.1007/s13311-015-0397-z] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Disease-modifying alternatives are sorely needed for the treatment of neurodegenerative disorders, a group of diseases that afflict approximately 50 million Americans annually. Immunotherapy is one of the most developed approaches in this direction. Vaccination against amyloid-β, α-synuclein, or tau has been extensively explored, specially as the discovery that these proteins may propagate cell-to-cell and be accessible to antibodies when embedded into the plasma membrane or in the extracellular space. Likewise, the use of passive immunization approaches with specific antibodies against abnormal conformations of these proteins has also yielded promising results. The clinical development of immunotherapies for Alzheimer’s disease, Parkinson’s disease, frontotemporal dementia, dementia with Lewy bodies, and other neurodegenerative disorders is a field in constant evolution. Results to date suggest that immunotherapy is a promising therapeutic approach for neurodegenerative diseases that progress with the accumulation and prion-like propagation of toxic protein aggregates. Here we provide an overview of the most novel and relevant immunotherapeutic advances targeting amyloid-β in Alzheimer’s disease, α-synuclein in Alzheimer’s disease and Parkinson’s disease, and tau in Alzheimer’s disease and frontotemporal dementia.
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Affiliation(s)
- Elvira Valera
- grid.266100.30000000121074242Department of Neurosciences, University of California, La Jolla, San Diego, CA 92093 USA
| | - Brian Spencer
- grid.266100.30000000121074242Department of Neurosciences, University of California, La Jolla, San Diego, CA 92093 USA
| | - Eliezer Masliah
- grid.266100.30000000121074242Department of Neurosciences, University of California, La Jolla, San Diego, CA 92093 USA
- grid.266100.30000000121074242Department of Pathology, University of California, La Jolla, San Diego, CA 92093 USA
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25
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Baweja L, Balamurugan K, Subramanian V, Dhawan A. Effect of graphene oxide on the conformational transitions of amyloid beta peptide: A molecular dynamics simulation study. J Mol Graph Model 2015; 61:175-85. [PMID: 26275931 DOI: 10.1016/j.jmgm.2015.07.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 07/20/2015] [Accepted: 07/22/2015] [Indexed: 01/04/2023]
Abstract
The interactions between nanomaterials (NMs) and amyloid proteins are central to the nanotechnology-based diagnostics and therapy in neurodegenerative disorders such as Alzheimer's and Parkinson's. Graphene oxide (GO) and its derivatives have shown to modulate the aggregation pattern of disease causing amyloid beta (Aβ) peptide. However, the mechanism is still not well understood. Using molecular dynamics simulations, the effect of graphene oxide (GO) and reduced graphene oxide (rGO) having carbon:oxygen ratio of 4:1 and 10:1, respectively, on the conformational transitions (alpha-helix to beta-sheet) and the dynamics of the peptide was investigated. GO and rGO decreased the beta-strand propensity of amino acid residues in Aβ. The peptide displayed different modes of adsorption on GO and rGO. The adsorption on GO was dominated by electrostatic interactions, whereas on rGO, both van der Waals and electrostatic interactions contributed in the adsorption of the peptide. Our study revealed that the slight increase in the hydrophobic patches on rGO made it more effective inhibitor of conformational transitions in the peptide. Alpha helix-beta sheet transition in Aβ peptide could be one of the plausible mechanism by which graphene oxide may inhibit amyloid fibrillation.
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Affiliation(s)
- Lokesh Baweja
- Institute of Life Sciences, School of Science and Technology, Ahmedabad University, University Road, Ahmedabad 380009, Gujarat, India; Academy of Scientific and Innovative Research, Anusandhan Bhavan, 2 Rafi Marg, New Delhi 110001, India; CSIR-Indian Institute of Toxicology Research, Mahatma Gandhi Road, P.O. Box. 80, Lucknow 226001, Uttar Pradesh, India
| | - Kanagasabai Balamurugan
- CSIR-Central Leather Research Institute, Sardar Patel Road, Adyar, Chennai 600020, Tamil Nadu, India
| | - Venkatesan Subramanian
- Academy of Scientific and Innovative Research, Anusandhan Bhavan, 2 Rafi Marg, New Delhi 110001, India; CSIR-Central Leather Research Institute, Sardar Patel Road, Adyar, Chennai 600020, Tamil Nadu, India
| | - Alok Dhawan
- Academy of Scientific and Innovative Research, Anusandhan Bhavan, 2 Rafi Marg, New Delhi 110001, India; CSIR-Indian Institute of Toxicology Research, Mahatma Gandhi Road, P.O. Box. 80, Lucknow 226001, Uttar Pradesh, India.
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26
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Kitajima Y, Hori K, Konishi K, Tani M, Tomioka H, Akashi N, Hosoi M, Inamoto A, Hasegawa S, Kikuchi N, Takahashi A, Hachisu M. A Review of the Role of Anticholinergic Activity in Lewy Body Disease and Delirium. NEURODEGENER DIS 2015; 15:162-7. [PMID: 26138494 DOI: 10.1159/000381522] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We have previously proposed a hypothesis in which we argue that anticholinergic activity (AA) appears endogenously in Alzheimer's disease (AD). Acetylcholine (ACh) controls both cognitive function and inflammation. Consequently, when the downregulation of ACh reaches critical levels, the inflammatory system is upregulated and proinflammatory cytokines with AA appear. However, factors other than downregulation of ACh can produce AA; even if ACh downregulation does not reach critical levels, AA can still appear if one of these other AA-producing factors is added. These factors can include neurocognitive disorders other than AD, such as delirium and Lewy body disease (LBD). In delirium, ACh downregulation fails to reach critical levels, but AA appears due to the use of medicines, physical illnesses or mental stress (termed 'AA inserts'). In LBD, we speculate that AA appears endogenously, even in the absence of severe cognitive dysfunction, for 2 reasons. One reason is that patterns of ACh deterioration are different in LBD from those in AD, with synergistic actions between amyloid and α-synuclein thought to cause additional or severe symptoms that accelerate the disease course. The second reason is that AA occurs through disinhibition by reduced cortisol levels that result from severe autonomic parasympathetic dysfunction in LBD.
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Affiliation(s)
- Yuka Kitajima
- Department of Anesthesiology, School of Medicine, Juntendo University, Tokyo, Japan
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