1
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Yi Y, Lim MH. Current understanding of metal-dependent amyloid-β aggregation and toxicity. RSC Chem Biol 2023; 4:121-131. [PMID: 36794021 PMCID: PMC9906324 DOI: 10.1039/d2cb00208f] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/22/2022] [Indexed: 11/23/2022] Open
Abstract
The discovery of effective therapeutics targeting amyloid-β (Aβ) aggregates for Alzheimer's disease (AD) has been very challenging, which suggests its complicated etiology associated with multiple pathogenic elements. In AD-affected brains, highly concentrated metals, such as copper and zinc, are found in senile plaques mainly composed of Aβ aggregates. These metal ions are coordinated to Aβ and affect its aggregation and toxicity profiles. In this review, we illustrate the current view on molecular insights into the assembly of Aβ peptides in the absence and presence of metal ions as well as the effect of metal ions on their toxicity.
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Affiliation(s)
- Yelim Yi
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea
| | - Mi Hee Lim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 Republic of Korea
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2
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Szała-Mendyk B, Molski A. Side Chain Geometry Determines the Fibrillation Propensity of a Minimal Two-Beads-per-Residue Peptide Model. J Phys Chem B 2022; 126:5772-5780. [PMID: 35917439 PMCID: PMC9376954 DOI: 10.1021/acs.jpcb.2c03502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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The molecular mechanism of fibrillation is an important
issue for
understanding peptide aggregation. In our previous work, we demonstrated
that the interchain attraction and intrachain bending stiffness control
the aggregation kinetics and transient aggregate morphologies of a
one-bead-per-residue implicit solvent peptide model. However, that
model did not lead to fibrillation. In this work, we study the molecular
origin of fibril formation using a two-beads-per-residue model, where
one bead represents the backbone residue atoms and the other the side
chain atoms. We show that the side chain geometry determines the fibrillation
propensity that is further modulated by the modified terminal beads.
This allows us to bring out the effects of side chain geometry and
terminal capping on the fibrillation propensity. Our model does not
assume a secondary structure and is, perhaps, the simplest bead-based
chain model leading to fibrillation.
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Affiliation(s)
- Beata Szała-Mendyk
- Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland
| | - Andrzej Molski
- Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland
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3
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Mrdenovic D, Pieta IS, Nowakowski R, Kutner W, Lipkowski J, Pieta P. Amyloid β interaction with model cell membranes – What are the toxicity-defining properties of amyloid β? Int J Biol Macromol 2022; 200:520-531. [DOI: 10.1016/j.ijbiomac.2022.01.117] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 01/10/2022] [Accepted: 01/18/2022] [Indexed: 01/26/2023]
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4
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Tang Y, Zhang D, Gong X, Zheng J. A mechanistic survey of Alzheimer's disease. Biophys Chem 2021; 281:106735. [PMID: 34894476 DOI: 10.1016/j.bpc.2021.106735] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/26/2021] [Accepted: 11/26/2021] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is the most common, age-dependent neurodegenerative disorder. While AD has been intensively studied from different aspects, there is no effective cure for AD, largely due to a lack of a clear mechanistic understanding of AD. In this mini-review, we mainly focus on the discussion and summary of mechanistic causes of Alzheimer's disease (AD). While different AD mechanisms illustrate different molecular and cellular pathways in AD pathogenesis, they do not necessarily exclude each other. Instead, some of them could work together to initiate, trigger, and promote the onset and development of AD. In a broader viewpoint, some AD mechanisms (e.g., amyloid aggregation mechanism, microbial infection/neuroinflammation mechanism, and amyloid cross-seeding mechanism) could also be applicable to other amyloid diseases including type II diabetes, Parkinson's disease, and prion disease. Such common mechanisms for AD and other amyloid diseases explain not only the pathogenesis of individual amyloid diseases, but also the spreading of pathologies between these diseases, which will inspire new strategies for therapeutic intervention and prevention for AD.
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Affiliation(s)
- Yijing Tang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, OH, United States of America
| | - Dong Zhang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, OH, United States of America
| | - Xiong Gong
- Department of Polymer Engineering, The University of Akron, OH, United States of America
| | - Jie Zheng
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, OH, United States of America.
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5
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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: 2] [Impact Index Per Article: 0.7] [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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6
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Sahoo BR, Cox SJ, Ramamoorthy A. High-resolution probing of early events in amyloid-β aggregation related to Alzheimer's disease. Chem Commun (Camb) 2020; 56:4627-4639. [PMID: 32300761 PMCID: PMC7254607 DOI: 10.1039/d0cc01551b] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In Alzheimer's disease (AD), soluble oligomers of amyloid-β (Aβ) are emerging as a crucial entity in driving disease progression as compared to insoluble amyloid deposits. The lacuna in establishing the structure to function relationship for Aβ oligomers prevents the development of an effective treatment for AD. While the transient and heterogeneous properties of Aβ oligomers impose many challenges for structural investigation, an effective use of a combination of NMR techniques has successfully identified and characterized them at atomic-resolution. Here, we review the successful utilization of solution and solid-state NMR techniques to probe the aggregation and structures of small and large oligomers of Aβ. Biophysical studies utilizing the commonly used solution and 19F based NMR experiments to identify the formation of small size early intermediates and to obtain their structures, and dock-lock mechanism of fiber growth at atomic-resolution are discussed. In addition, the use of proton-detected magic angle spinning (MAS) solid-state NMR experiments to obtain high-resolution insights into the aggregation pathways and structures of large oligomers and other aggregates is also presented. We expect these NMR based studies to be valuable for real-time monitoring of the depletion of monomers and the formation of toxic oligomers and high-order aggregates under a variety of conditions, and to solve the high-resolution structures of small and large size oligomers for most amyloid proteins, and therefore to develop inhibitors and drugs.
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Affiliation(s)
- Bikash R Sahoo
- Biophysics Program, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
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7
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Faujan NH, Abedi Karjiban R, Kashaban I, Basri M, Basri H. Computational simulation of palm kernel oil-based esters nano-emulsions aggregation as a potential parenteral drug delivery system. ARAB J CHEM 2019. [DOI: 10.1016/j.arabjc.2015.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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8
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Bode DC, Freeley M, Nield J, Palma M, Viles JH. Amyloid-β oligomers have a profound detergent-like effect on lipid membrane bilayers, imaged by atomic force and electron microscopy. J Biol Chem 2019; 294:7566-7572. [PMID: 30948512 DOI: 10.1074/jbc.ac118.007195] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 03/27/2019] [Indexed: 12/19/2022] Open
Abstract
The ability of amyloid-β peptide (Aβ) to disrupt membrane integrity and cellular homeostasis is believed to be central to Alzheimer's disease pathology. Aβ is reported to have various impacts on the lipid bilayer, but a clearer picture of Aβ influence on membranes is required. Here, we use atomic force and transmission electron microscopies to image the impact of different isolated Aβ assembly types on lipid bilayers. We show that only oligomeric Aβ can profoundly disrupt the bilayer, visualized as widespread lipid extraction and subsequent deposition, which can be likened to an effect expected from the action of a detergent. We further show that Aβ oligomers cause widespread curvature and discontinuities within lipid vesicle membranes. In contrast, this detergent-like effect was not observed for Aβ monomers and fibers, although Aβ fibers did laterally associate and embed into the upper leaflet of the bilayer. The marked impact of Aβ oligomers on membrane integrity identified here reveals a mechanism by which these oligomers may be cytotoxic.
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Affiliation(s)
- David C Bode
- From the School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Mark Freeley
- From the School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Jon Nield
- From the School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Matteo Palma
- From the School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom
| | - John H Viles
- From the School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom
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9
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Martinez Hernandez A, Urbanke H, Gillman AL, Lee J, Ryazanov S, Agbemenyah HY, Benito E, Jain G, Kaurani L, Grigorian G, Leonov A, Rezaei-Ghaleh N, Wilken P, Arce FT, Wagner J, Fuhrmann M, Caruana M, Camilleri A, Vassallo N, Zweckstetter M, Benz R, Giese A, Schneider A, Korte M, Lal R, Griesinger C, Eichele G, Fischer A. The diphenylpyrazole compound anle138b blocks Aβ channels and rescues disease phenotypes in a mouse model for amyloid pathology. EMBO Mol Med 2019; 10:32-47. [PMID: 29208638 PMCID: PMC5760857 DOI: 10.15252/emmm.201707825] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Alzheimer's disease is a devastating neurodegenerative disease eventually leading to dementia. An effective treatment does not yet exist. Here we show that oral application of the compound anle138b restores hippocampal synaptic and transcriptional plasticity as well as spatial memory in a mouse model for Alzheimer's disease, when given orally before or after the onset of pathology. At the mechanistic level, we provide evidence that anle138b blocks the activity of conducting Aβ pores without changing the membrane embedded Aβ-oligomer structure. In conclusion, our data suggest that anle138b is a novel and promising compound to treat AD-related pathology that should be investigated further.
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Affiliation(s)
- Ana Martinez Hernandez
- Department for Epigenetics and Systems Medicine in Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany.,Department for Genes and Behavior, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Hendrik Urbanke
- Department for Epigenetics and Systems Medicine in Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Alan L Gillman
- Department of Bioengineering, Materials Science and Engineering, Department of Mechanical and Aerospace Engineering and Institute of Engineering in Medicine, University of California San Diego, La Jolla, CA, USA
| | - Joon Lee
- Department of Bioengineering, Materials Science and Engineering, Department of Mechanical and Aerospace Engineering and Institute of Engineering in Medicine, University of California San Diego, La Jolla, CA, USA
| | - Sergey Ryazanov
- Department of NMR Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,DFG Research Center Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Hope Y Agbemenyah
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany
| | - Eva Benito
- Department for Epigenetics and Systems Medicine in Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Gaurav Jain
- Department for Epigenetics and Systems Medicine in Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Lalit Kaurani
- DFG Research Center Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Gayane Grigorian
- Department of Cellular Neurobiology, Technical University Braunschweig, Braunschweig, Germany
| | - Andrei Leonov
- Department of NMR Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,DFG Research Center Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Nasrollah Rezaei-Ghaleh
- Department of NMR Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Department of Translational Structural Biology of Dementia, German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - Petra Wilken
- DFG Research Center Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany.,Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany.,Group for Translational Research in Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE) Göttingen, Göttingen, Germany
| | - Fernando Teran Arce
- Department of Bioengineering, Materials Science and Engineering, Department of Mechanical and Aerospace Engineering and Institute of Engineering in Medicine, University of California San Diego, La Jolla, CA, USA
| | - Jens Wagner
- Group for Neuroimmunology and Imaging, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Martin Fuhrmann
- Group for Neuroimmunology and Imaging, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Mario Caruana
- Department of Physiology and Biochemistry, Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Angelique Camilleri
- Department of Physiology and Biochemistry, Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Neville Vassallo
- Department of Physiology and Biochemistry, Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Markus Zweckstetter
- Department of NMR Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,DFG Research Center Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany.,Department of Translational Structural Biology of Dementia, German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany.,Department of Neurology, University Medical Center Göttingen, University of Göttingen, Göttingen, Germany
| | - Roland Benz
- Life Sciences and Chemistry, Jacobs University of Bremen, Bremen, Germany
| | - Armin Giese
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Anja Schneider
- DFG Research Center Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany.,Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany.,Group for Translational Research in Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE) Göttingen, Göttingen, Germany
| | - Martin Korte
- Department of Cellular Neurobiology, Technical University Braunschweig, Braunschweig, Germany .,Helmholtz Center for Infections Research, Braunschweig, Germany
| | - Ratnesh Lal
- Department of Bioengineering, Materials Science and Engineering, Department of Mechanical and Aerospace Engineering and Institute of Engineering in Medicine, University of California San Diego, La Jolla, CA, USA
| | - Christian Griesinger
- Department of NMR Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany .,DFG Research Center Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Gregor Eichele
- Department for Genes and Behavior, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Andre Fischer
- Department for Epigenetics and Systems Medicine in Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany .,Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany
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10
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Rangachari V, Dean DN, Rana P, Vaidya A, Ghosh P. Cause and consequence of Aβ - Lipid interactions in Alzheimer disease pathogenesis. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2018; 1860:1652-1662. [PMID: 29526709 PMCID: PMC6133763 DOI: 10.1016/j.bbamem.2018.03.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 02/28/2018] [Accepted: 03/02/2018] [Indexed: 12/14/2022]
Abstract
Self-templating propagation of protein aggregate conformations is increasingly becoming a significant factor in many neurological diseases. In Alzheimer disease (AD), intrinsically disordered amyloid-β (Aβ) peptides undergo aggregation that is sensitive to environmental conditions. High-molecular weight aggregates of Aβ that form insoluble fibrils are deposited as senile plaques in AD brains. However, low-molecular weight aggregates called soluble oligomers are known to be the primary toxic agents responsible for neuronal dysfunction. The aggregation process is highly stochastic involving both homotypic (Aβ-Aβ) and heterotypic (Aβ with interacting partners) interactions. Two of the important members of interacting partners are membrane lipids and surfactants, to which Aβ shows a perpetual association. Aβ-membrane interactions have been widely investigated for more than two decades, and this research has provided a wealth of information. Although this has greatly enriched our understanding, the objective of this review is to consolidate the information from the literature that collectively showcases the unique phenomenon of lipid-mediated Aβ oligomer generation, which has largely remained inconspicuous. This is especially important because Aβ aggregate "strains" are increasingly becoming relevant in light of the correlations between the structure of aggregates and AD phenotypes. Here, we will focus on aspects of Aβ-lipid interactions specifically from the context of how lipid modulation generates a wide variety of biophysically and biochemically distinct oligomer sub-types. This, we believe, will refocus our thinking on the influence of lipids and open new approaches in delineating the mechanisms of AD pathogenesis. This article is part of a Special Issue entitled: Protein Aggregation and Misfolding at the Cell Membrane Interface edited by Ayyalusamy Ramamoorthy.
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Affiliation(s)
- Vijayaraghavan Rangachari
- Department of Chemistry & Biochemistry, University of Southern Mississippi, Hattiesburg, MS 39406, USA.
| | - Dexter N Dean
- Department of Chemistry & Biochemistry, University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Pratip Rana
- Department of Computer Science, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Ashwin Vaidya
- Department of Mathematical Science, Montclair State University, Montclair, NJ 07043, USA
| | - Preetam Ghosh
- Department of Computer Science, Virginia Commonwealth University, Richmond, VA 23284, USA
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11
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Press-Sandler O, Miller Y. Molecular mechanisms of membrane-associated amyloid aggregation: Computational perspective and challenges. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1889-1905. [DOI: 10.1016/j.bbamem.2018.03.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/07/2018] [Accepted: 03/12/2018] [Indexed: 01/02/2023]
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12
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β-barrel Oligomers as Common Intermediates of Peptides Self-Assembling into Cross-β Aggregates. Sci Rep 2018; 8:10353. [PMID: 29985420 PMCID: PMC6037789 DOI: 10.1038/s41598-018-28649-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 06/22/2018] [Indexed: 12/22/2022] Open
Abstract
Oligomers populated during the early amyloid aggregation process are more toxic than mature fibrils, but pinpointing the exact toxic species among highly dynamic and heterogeneous aggregation intermediates remains a major challenge. β-barrel oligomers, structurally-determined recently for a slow-aggregating peptide derived from αB crystallin, are attractive candidates for exerting amyloid toxicity due to their well-defined structures as therapeutic targets and compatibility to the "amyloid-pore" hypothesis of toxicity. To assess whether β-barrel oligomers are common intermediates to amyloid peptides - a necessary step toward associating β-barrel oligomers with general amyloid cytotoxicity, we computationally studied the oligomerization and fibrillization dynamics of seven well-studied fragments of amyloidogenic proteins with different experimentally-determined aggregation morphologies and cytotoxicity. In our molecular dynamics simulations, β-barrel oligomers were only observed in five peptides self-assembling into the characteristic cross-β aggregates, but not the other two that formed polymorphic β-rich aggregates as reported experimentally. Interestingly, the latter two peptides were previously found nontoxic. Hence, the observed correlation between β-barrel oligomers formation and cytotoxicity supports the hypothesis of β-barrel oligomers as the common toxic intermediates of amyloid aggregation.
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13
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Ge X, Sun Y, Ding F. Structures and dynamics of β-barrel oligomer intermediates of amyloid-beta16-22 aggregation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1687-1697. [PMID: 29550287 DOI: 10.1016/j.bbamem.2018.03.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/06/2018] [Accepted: 03/07/2018] [Indexed: 01/13/2023]
Abstract
Accumulating evidence suggests that soluble oligomers are more toxic than final fibrils of amyloid aggregations. Among the mixture of inter-converting intermediates with continuous distribution of sizes and secondary structures, oligomers in the β-barrel conformation - a common class of protein folds with a closed β-sheet - have been postulated as the toxic species with well-defined three-dimensional structures to perform pathological functions. A common mechanism for amyloid toxicity, therefore, implies that all amyloid peptides should be able to form β-barrel oligomers as the aggregation intermediates. Here, we applied all-atom discrete molecular dynamics (DMD) simulations to evaluate the formation of β-barrel oligomers and characterize their structures and dynamics in the aggregation of a seven-residue amyloid peptide, corresponding to the amyloid core of amyloid-β with a sequence of 16KLVFFAE22 (Aβ16-22). We carried out aggregation simulations with various numbers of peptides to study the size dependence of aggregation dynamics and assembly structures. Consistent with previous computational studies, we observed the formation of β-barrel oligomers in all-atom DMD simulations. Using a network-based approach to automatically identify β-barrel conformations, we systematically characterized β-barrels of various sizes. Our simulations revealed the conformational inter-conversion between β-barrels and double-layer β-sheets due to increased structural strains upon forming a closed β-barrel while maximizing backbone hydrogen bonds. The potential of mean force analysis further characterized the free energy barriers between these two states. The obtained structural and dynamic insights of β-barrel oligomers may help better understand the molecular mechanism of oligomer toxicities and design novel therapeutics targeting the toxic β-barrel oligomers. This article is part of a Special Issue entitled: Protein Aggregation and Misfolding at the Cell Membrane Interface edited by Ayyalusamy Ramamoorthy.
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Affiliation(s)
- Xinwei Ge
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
| | - Yunxiang Sun
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States
| | - Feng Ding
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, United States.
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14
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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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15
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Xiang N, Lyu Y, Zhu X, Narsimhan G. Investigation of the interaction of amyloid β peptide (11–42) oligomers with a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membrane using molecular dynamics simulation. Phys Chem Chem Phys 2018; 20:6817-6829. [PMID: 29299557 DOI: 10.1039/c7cp07148e] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanism of pore formation in model neural cell membranes by β amyloid (Aβ) peptides was investigated using molecular dynamics simulation which indicated that Aβ oligomers of size equal or greater than 3 has a higher tendency for pore formation than monomers and that cholesterol tends to retard Aβ binding and insertion into the membrane.
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Affiliation(s)
- Ning Xiang
- Department of Agricultural and Biological Engineering
- Purdue University
- West Lafayette
- USA
| | - Yuan Lyu
- Department of Agricultural and Biological Engineering
- Purdue University
- West Lafayette
- USA
| | - Xiao Zhu
- ItaP
- Research Computing
- Rosen Center for Advanced Computing
- Purdue University
- West Lafayette
| | - Ganesan Narsimhan
- Department of Agricultural and Biological Engineering
- Purdue University
- West Lafayette
- USA
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16
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Qian Z, Zhang Q, Liu Y, Chen P. Assemblies of amyloid-β30-36 hexamer and its G33V/L34T mutants by replica-exchange molecular dynamics simulation. PLoS One 2017; 12:e0188794. [PMID: 29186195 PMCID: PMC5706729 DOI: 10.1371/journal.pone.0188794] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 11/13/2017] [Indexed: 02/02/2023] Open
Abstract
The aggregation of amyloid-β peptides is associated with the pathogenesis of Alzheimer’s disease, in which the 30–36 fragments play an important part as a fiber-forming hydrophobic region. The fibrillar structure of Aβ30–36 has been detected by means of X-ray diffraction, but its oligomeric structural determination, biophysical characterization, and pathological mechanism remain elusive. In this study, we have investigated the structures of Aβ30–36 hexamer as well as its G33V and L34T mutants in explicit water environment using replica-exchange molecular dynamics (REMD) simulations. Our results show that the wild-type (WT) Aβ30–36 hexamer has a preference to form β-barrel and bilayer β-sheet conformations, while the G33V or L34T mutation disrupts the β-barrel structures: the G33V mutant is homogenized to adopt β-sheet-rich bilayers, and the structures of L34T mutant on the contrary get more diverse. The hydrophobic interaction plays a critical role in the formation and stability of oligomeric assemblies among all the three systems. In addition, the substitution of G33 by V reduces the β-sheet content in the most populated conformations of Aβ30–36 oligomers through a steric effect. The L34T mutation disturbs the interpeptide hydrogen bonding network, and results in the increased coil content and morphological diversity. Our REMD runs provide structural details of WT and G33V/L34T mutant Aβ30–36 oligomers, and molecular insight into the aggregation mechanism, which will be helpful for designing novel inhibitors or amyloid-based materials.
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Affiliation(s)
- Zhenyu Qian
- Key Laboratory of Exercise and Health Sciences (Ministry of Education) and School of Kinesiology, Shanghai University of Sport, Shanghai, China
- * E-mail: (ZQ); (PC)
| | - Qingwen Zhang
- College of Physical Education and Training, Shanghai University of Sport, Shanghai, China
| | - Yu Liu
- Key Laboratory of Exercise and Health Sciences (Ministry of Education) and School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Peijie Chen
- Key Laboratory of Exercise and Health Sciences (Ministry of Education) and School of Kinesiology, Shanghai University of Sport, Shanghai, China
- * E-mail: (ZQ); (PC)
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17
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Dong X, Sun Y, Wei G, Nussinov R, Ma B. Binding of protofibrillar Aβ trimers to lipid bilayer surface enhances Aβ structural stability and causes membrane thinning. Phys Chem Chem Phys 2017; 19:27556-27569. [PMID: 28979963 PMCID: PMC5647258 DOI: 10.1039/c7cp05959k] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Alzheimer's disease, a common neurodegenerative disease, is characterized by the aggregation of amyloid-β (Aβ) peptides. The interactions of Aβ with membranes cause changes in membrane morphology and ion permeation, which are responsible for its neurotoxicity and can accelerate fibril growth. However, the Aβ-lipid interactions and how these induce membrane perturbation and disruption at the atomic level and the consequences for the Aβ organization are not entirely understood. Here, we perform multiple atomistic molecular dynamics simulations on three protofibrillar Aβ9-40 trimers. Our simulations show that, regardless of the morphologies and the initial orientations of the three different protofibrillar Aβ9-40 trimers, the N-terminal β-sheet of all trimers preferentially binds to the membrane surface. The POPG lipid bilayers enhance the structural stability of protofibrillar Aβ trimers by stabilizing inter-peptide β-sheets and D23-K28 salt-bridges. The interaction causes local membrane thinning. We found that the trimer structure related to Alzheimer's disease brain tissue () is the most stable both in water solution and at membrane surface, and displays slightly stronger membrane perturbation capability. These results provide mechanistic insights into the membrane-enhanced structural stability of protofibrillar Aβ oligomers and the first step of Aβ-induced membrane disruption at the atomic level.
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Affiliation(s)
- Xuewei Dong
- Department of Physics, State Key Laboratory of Surface physics, Key Laboratory for Computational Physical Science (Ministry of Education), Collaborative Innovation Center of Advanced Microstructures (Nanjing), Fudan University, Shanghai 200433, People's Republic of China
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18
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Ngo ST, Hung HM, Tran KN, Nguyen MT. Replica exchange molecular dynamics study of the amyloid beta (11–40) trimer penetrating a membrane. RSC Adv 2017. [DOI: 10.1039/c6ra26461a] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The transmembrane Aβ11–40 trimer is investigated for the first time using REMD and FEP.
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Affiliation(s)
- Son Tung Ngo
- Computational Chemistry Research Group
- Ton Duc Thang University
- Ho Chi Minh City
- Vietnam
- Faculty of Applied Sciences
| | | | - Khoa Nhat Tran
- Department of Biological Sciences
- University of Maryland Baltimore County
- 21250 Baltimore
- USA
| | - Minh Tho Nguyen
- Computational Chemistry Research Group
- Ton Duc Thang University
- Ho Chi Minh City
- Vietnam
- Faculty of Applied Sciences
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19
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Zhang M, Ren B, Chen H, Sun Y, Ma J, Jiang B, Zheng J. Molecular Simulations of Amyloid Structures, Toxicity, and Inhibition. Isr J Chem 2016. [DOI: 10.1002/ijch.201600075] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Mingzhen Zhang
- Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325 USA
| | - Baiping Ren
- Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325 USA
| | - Hong Chen
- Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325 USA
| | - Yan Sun
- Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology Tianjin University Tianjin 300072 P. R. China
| | - Jie Ma
- Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325 USA
- State Key Laboratory of Pollution Control and Resource Reuse School of Environmental Science and Engineering Tongji University Shanghai 200092 P. R. China
| | - Binbo Jiang
- Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325 USA
- College of Chemical and Biological Engineering Zhejiang University Hangzhou Zhejiang 310027 P. R. China
| | - Jie Zheng
- Department of Chemical and Biomolecular Engineering The University of Akron Akron OH 44325 USA
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20
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Gillman AL, Lee J, Ramachandran S, Capone R, Gonzalez T, Wrasidlo W, Masliah E, Lal R. Small molecule NPT-440-1 inhibits ionic flux through Aβ 1-42 pores: Implications for Alzheimer's disease therapeutics. NANOMEDICINE : NANOTECHNOLOGY, BIOLOGY, AND MEDICINE 2016; 12:2331-2340. [PMID: 27335341 PMCID: PMC5116404 DOI: 10.1016/j.nano.2016.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 05/31/2016] [Accepted: 06/04/2016] [Indexed: 12/11/2022]
Abstract
Increased levels of soluble amyloid-beta (Aβ) oligomers are suspected to underlie Alzheimer's disease (AD) pathophysiology. These oligomers have been shown to form multi-subunit Aβ pores in bilayers and induce uncontrolled, neurotoxic, ion flux, particularly calcium ions, across cellular membranes that might underlie cognitive impairment in AD. Small molecule interventions that modulate pore activity could effectively prevent or ameliorate their toxic activity. Here we examined the efficacy of a small molecule, NPT-440-1, on modulating amyloid pore permeability. Co-incubation of B103 rat neuronal cells with NPT-440-1 and Aβ1-42 prevented calcium influx. In purified lipid bilayers, we show that a 10-15min preincubation, prior to membrane introduction, was required to prevent conductance. Thioflavin-T and circular dichroism both suggested a reduction in Aβ1-42 β-sheet content during this incubation period. Combined with previous studies on site-specific amino acid substitutions, these results suggest that pharmacological modulation of Aβ1-42 could prevent amyloid pore-mediated AD pathogenesis.
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Affiliation(s)
- Alan L Gillman
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States
| | - Joon Lee
- Department of Mechanical and Aerospace Engineering University of California, San Diego, La Jolla, CA, United States
| | - Srinivasan Ramachandran
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States; Department of Mechanical and Aerospace Engineering University of California, San Diego, La Jolla, CA, United States
| | - Ricardo Capone
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States
| | - Tania Gonzalez
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States
| | - Wolf Wrasidlo
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States; Neuropore Therapies, Inc., San Diego, CA, United States
| | - Eliezer Masliah
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States.
| | - Ratnesh Lal
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States; Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA, United States; Department of Mechanical and Aerospace Engineering University of California, San Diego, La Jolla, CA, United States.
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21
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Cryo-EM structure of aerolysin variants reveals a novel protein fold and the pore-formation process. Nat Commun 2016; 7:12062. [PMID: 27405240 PMCID: PMC4947156 DOI: 10.1038/ncomms12062] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 05/25/2016] [Indexed: 12/19/2022] Open
Abstract
Owing to their pathogenical role and unique ability to exist both as soluble proteins and transmembrane complexes, pore-forming toxins (PFTs) have been a focus of microbiologists and structural biologists for decades. PFTs are generally secreted as water-soluble monomers and subsequently bind the membrane of target cells. Then, they assemble into circular oligomers, which undergo conformational changes that allow membrane insertion leading to pore formation and potentially cell death. Aerolysin, produced by the human pathogen Aeromonas hydrophila, is the founding member of a major PFT family found throughout all kingdoms of life. We report cryo-electron microscopy structures of three conformational intermediates and of the final aerolysin pore, jointly providing insight into the conformational changes that allow pore formation. Moreover, the structures reveal a protein fold consisting of two concentric β-barrels, tightly kept together by hydrophobic interactions. This fold suggests a basis for the prion-like ultrastability of aerolysin pore and its stoichiometry. Aerolysin is a secreted bacterial pore forming toxin that inserts into the host plasma membrane, potentially leading to cell death. Here the authors present Cryo-EM structures of aerolysin arrested at different stages of the pore formation process that provide insight into the conformational changes that allow pore formation.
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22
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Yan R, Fan Q, Zhou J, Vassar R. Inhibiting BACE1 to reverse synaptic dysfunctions in Alzheimer's disease. Neurosci Biobehav Rev 2016; 65:326-40. [PMID: 27044452 PMCID: PMC4856578 DOI: 10.1016/j.neubiorev.2016.03.025] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 03/25/2016] [Accepted: 03/29/2016] [Indexed: 12/21/2022]
Abstract
Over the past two decades, many studies have identified significant contributions of toxic β-amyloid peptides (Aβ) to the etiology of Alzheimer's disease (AD), which is the most common age-dependent neurodegenerative disease. AD is also recognized as a disease of synaptic failure. Aβ, generated by sequential proteolytic cleavages of amyloid precursor protein (APP) by BACE1 and γ-secretase, is one of major culprits that cause this failure. In this review, we summarize current findings on how BACE1-cleaved APP products impact learning and memory through proteins localized on glutamatergic, GABAergic, and dopaminergic synapses. Considering the broad effects of Aβ on all three types of synapses, BACE1 inhibition emerges as a practical approach for ameliorating Aβ-mediated synaptic dysfunctions. Since BACE1 inhibitory drugs are currently in clinical trials, this review also discusses potential complications arising from BACE1 inhibition. We emphasize that the benefits of BACE1 inhibitory drugs will outweigh the concerns.
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Affiliation(s)
- Riqiang Yan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
| | - Qingyuan Fan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - John Zhou
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Robert Vassar
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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23
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Structure of amyloid oligomers and their mechanisms of toxicities: Targeting amyloid oligomers using novel therapeutic approaches. Eur J Med Chem 2016; 114:41-58. [DOI: 10.1016/j.ejmech.2016.02.065] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 02/25/2016] [Accepted: 02/25/2016] [Indexed: 01/22/2023]
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24
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Do TD, LaPointe NE, Nelson R, Krotee P, Hayden EY, Ulrich B, Quan S, Feinstein SC, Teplow DB, Eisenberg D, Shea JE, Bowers MT. Amyloid β-Protein C-Terminal Fragments: Formation of Cylindrins and β-Barrels. J Am Chem Soc 2016; 138:549-57. [PMID: 26700445 DOI: 10.1021/jacs.5b09536] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In order to evaluate potential therapeutic targets for treatment of amyloidoses such as Alzheimer's disease (AD), it is essential to determine the structures of toxic amyloid oligomers. However, for the amyloid β-protein peptide (Aβ), thought to be the seminal neuropathogenetic agent in AD, its fast aggregation kinetics and the rapid equilibrium dynamics among oligomers of different size pose significant experimental challenges. Here we use ion-mobility mass spectrometry, in combination with electron microscopy, atomic force microscopy, and computational modeling, to test the hypothesis that Aβ peptides can form oligomeric structures resembling cylindrins and β-barrels. These structures are hypothesized to cause neuronal injury and death through perturbation of plasma membrane integrity. We show that hexamers of C-terminal Aβ fragments, including Aβ(24-34), Aβ(25-35) and Aβ(26-36), have collision cross sections similar to those of cylindrins. We also show that linking two identical fragments head-to-tail using diglycine increases the proportion of cylindrin-sized oligomers. In addition, we find that larger oligomers of these fragments may adopt β-barrel structures and that β-barrels can be formed by folding an out-of-register β-sheet, a common type of structure found in amyloid proteins.
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Affiliation(s)
- Thanh D Do
- Department of Chemistry and Biochemistry and ‡Department of Physics, ¶Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California , Santa Barbara, California 93106, United States.,Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, and ∥Department of Neurology, David Geffen School of Medicine at UCLA, ∇Mary S. Easton Center for Alzheimer's Disease Research at UCLA, and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
| | - Nichole E LaPointe
- Department of Chemistry and Biochemistry and ‡Department of Physics, ¶Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California , Santa Barbara, California 93106, United States.,Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, and ∥Department of Neurology, David Geffen School of Medicine at UCLA, ∇Mary S. Easton Center for Alzheimer's Disease Research at UCLA, and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
| | - Rebecca Nelson
- Department of Chemistry and Biochemistry and ‡Department of Physics, ¶Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California , Santa Barbara, California 93106, United States.,Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, and ∥Department of Neurology, David Geffen School of Medicine at UCLA, ∇Mary S. Easton Center for Alzheimer's Disease Research at UCLA, and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
| | - Pascal Krotee
- Department of Chemistry and Biochemistry and ‡Department of Physics, ¶Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California , Santa Barbara, California 93106, United States.,Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, and ∥Department of Neurology, David Geffen School of Medicine at UCLA, ∇Mary S. Easton Center for Alzheimer's Disease Research at UCLA, and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
| | - Eric Y Hayden
- Department of Chemistry and Biochemistry and ‡Department of Physics, ¶Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California , Santa Barbara, California 93106, United States.,Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, and ∥Department of Neurology, David Geffen School of Medicine at UCLA, ∇Mary S. Easton Center for Alzheimer's Disease Research at UCLA, and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
| | - Brittany Ulrich
- Department of Chemistry and Biochemistry and ‡Department of Physics, ¶Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California , Santa Barbara, California 93106, United States.,Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, and ∥Department of Neurology, David Geffen School of Medicine at UCLA, ∇Mary S. Easton Center for Alzheimer's Disease Research at UCLA, and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
| | - Sarah Quan
- Department of Chemistry and Biochemistry and ‡Department of Physics, ¶Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California , Santa Barbara, California 93106, United States.,Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, and ∥Department of Neurology, David Geffen School of Medicine at UCLA, ∇Mary S. Easton Center for Alzheimer's Disease Research at UCLA, and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
| | - Stuart C Feinstein
- Department of Chemistry and Biochemistry and ‡Department of Physics, ¶Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California , Santa Barbara, California 93106, United States.,Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, and ∥Department of Neurology, David Geffen School of Medicine at UCLA, ∇Mary S. Easton Center for Alzheimer's Disease Research at UCLA, and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
| | - David B Teplow
- Department of Chemistry and Biochemistry and ‡Department of Physics, ¶Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California , Santa Barbara, California 93106, United States.,Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, and ∥Department of Neurology, David Geffen School of Medicine at UCLA, ∇Mary S. Easton Center for Alzheimer's Disease Research at UCLA, and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
| | - David Eisenberg
- Department of Chemistry and Biochemistry and ‡Department of Physics, ¶Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California , Santa Barbara, California 93106, United States.,Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, and ∥Department of Neurology, David Geffen School of Medicine at UCLA, ∇Mary S. Easton Center for Alzheimer's Disease Research at UCLA, and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry and ‡Department of Physics, ¶Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California , Santa Barbara, California 93106, United States.,Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, and ∥Department of Neurology, David Geffen School of Medicine at UCLA, ∇Mary S. Easton Center for Alzheimer's Disease Research at UCLA, and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
| | - Michael T Bowers
- Department of Chemistry and Biochemistry and ‡Department of Physics, ¶Neuroscience Research Institute and Department of Molecular, Cellular and Developmental Biology, University of California , Santa Barbara, California 93106, United States.,Departments of Chemistry and Biochemistry and Biological Chemistry, Howard Hughes Medical Institute, UCLA-DOE Institute for Genomics and Proteomics, and ∥Department of Neurology, David Geffen School of Medicine at UCLA, ∇Mary S. Easton Center for Alzheimer's Disease Research at UCLA, and Brain Research Institute and Molecular Biology Institute, University of California , 635 Charles Young Drive South, Los Angeles, California 90095, United States
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25
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Jang H, Arce FT, Lee J, Gillman AL, Ramachandran S, Kagan BL, Lal R, Nussinov R. Computational Methods for Structural and Functional Studies of Alzheimer's Amyloid Ion Channels. Methods Mol Biol 2016; 1345:251-68. [PMID: 26453217 PMCID: PMC7511997 DOI: 10.1007/978-1-4939-2978-8_16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Aggregation can be studied by a range of methods, experimental and computational. Aggregates form in solution, across solid surfaces, and on and in the membrane, where they may assemble into unregulated leaking ion channels. Experimental probes of ion channel conformations and dynamics are challenging. Atomistic molecular dynamics (MD) simulations are capable of providing insight into structural details of amyloid ion channels in the membrane at a resolution not achievable experimentally. Since data suggest that late stage Alzheimer's disease involves formation of toxic ion channels, MD simulations have been used aiming to gain insight into the channel shapes, morphologies, pore dimensions, conformational heterogeneity, and activity. These can be exploited for drug discovery. Here we describe computational methods to model amyloid ion channels containing the β-sheet motif at atomic scale and to calculate toxic pore activity in the membrane.
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Affiliation(s)
- Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, 1050 Boyles Street, Frederick, MD, 21702, USA.
| | - Fernando Teran Arce
- Department of Bioengineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Mechanical and Aerospace Engineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Joon Lee
- Department of Mechanical and Aerospace Engineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Alan L Gillman
- Department of Bioengineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Srinivasan Ramachandran
- Department of Bioengineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Mechanical and Aerospace Engineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Bruce L Kagan
- Department of Psychiatry, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, 90024, USA
| | - Ratnesh Lal
- Department of Bioengineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Mechanical and Aerospace Engineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, 1050 Boyles Street, Frederick, MD, 21702, USA.
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel.
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26
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Gilbert RJC. Protein-lipid interactions and non-lamellar lipidic structures in membrane pore formation and membrane fusion. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:487-99. [PMID: 26654785 DOI: 10.1016/j.bbamem.2015.11.026] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 10/23/2015] [Accepted: 11/30/2015] [Indexed: 12/27/2022]
Abstract
Pore-forming proteins and peptides act on their targeted lipid bilayer membranes to increase permeability. This approach to the modulation of biological function is relevant to a great number of living processes, including; infection, parasitism, immunity, apoptosis, development and neurodegeneration. While some pore-forming proteins/peptides assemble into rings of subunits to generate discrete, well-defined pore-forming structures, an increasing number is recognised to form pores via mechanisms which co-opt membrane lipids themselves. Among these, membrane attack complex-perforin/cholesterol-dependent cytolysin (MACPF/CDC) family proteins, Bax/colicin family proteins and actinoporins are especially prominent and among the mechanisms believed to apply are the formation of non-lamellar (semi-toroidal or toroidal) lipidic structures. In this review I focus on the ways in which lipids contribute to pore formation and contrast this with the ways in which lipids are co-opted also in membrane fusion and fission events. A variety of mechanisms for pore formation that involve lipids exists, but they consistently result in stable hybrid proteolipidic structures. These structures are stabilised by mechanisms in which pore-forming proteins modify the innate capacity of lipid membranes to respond to their environment, changing shape and/or phase and binding individual lipid molecules directly. In contrast, and despite the diversity in fusion protein types, mechanisms for membrane fusion are rather similar to each other, mapping out a pathway from pairs of separated compartments to fully confluent fused membranes. Fusion proteins generate metastable structures along the way which, like long-lived proteolipidic pore-forming complexes, rely on the basic physical properties of lipid bilayers. Membrane fission involves similar intermediates, in the reverse order. I conclude by considering the possibility that at least some pore-forming and fusion proteins are evolutionarily related homologues. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale.
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Affiliation(s)
- Robert J C Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.
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27
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Bhowmik D, Mote KR, MacLaughlin CM, Biswas N, Chandra B, Basu JK, Walker GC, Madhu PK, Maiti S. Cell-Membrane-Mimicking Lipid-Coated Nanoparticles Confer Raman Enhancement to Membrane Proteins and Reveal Membrane-Attached Amyloid-β Conformation. ACS NANO 2015; 9:9070-7. [PMID: 26391443 DOI: 10.1021/acsnano.5b03175] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Identifying the structures of membrane bound proteins is critical to understanding their function in healthy and diseased states. We introduce a surface enhanced Raman spectroscopy technique which can determine the conformation of membrane-bound proteins, at low micromolar concentrations, and also in the presence of a substantial membrane-free fraction. Unlike conventional surface enhanced Raman spectroscopy, our approach does not require immobilization of molecules, as it uses spontaneous binding of proteins to lipid bilayer-encapsulated Ag nanoparticles. We apply this technique to probe membrane-attached oligomers of Amyloid-β40 (Aβ40), whose conformation is keenly sought in the context of Alzheimer's disease. Isotope-shifts in the Raman spectra help us obtain secondary structure information at the level of individual residues. Our results show the presence of a β-turn, flanked by two β-sheet regions. We use solid-state NMR data to confirm the presence of the β-sheets in these regions. In the membrane-attached oligomer, we find a strongly contrasting and near-orthogonal orientation of the backbone H-bonds compared to what is found in the mature, less-toxic Aβ fibrils. Significantly, this allows a "porin" like β-barrel structure, providing a structural basis for proposed mechanisms of Aβ oligomer toxicity.
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Affiliation(s)
- Debanjan Bhowmik
- Department of Chemical Sciences, Tata Institute of Fundamental Research , Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Kaustubh R Mote
- TIFR Centre for Interdisciplinary Sciences , 21 Brundavan Colony, Narsinghi, Hyderabad 500075, India
| | - Christina M MacLaughlin
- Department of Chemistry, Lash Miller Laboratories, University of Toronto , Toronto, ON M5S 3H6, Canada
| | - Nupur Biswas
- Department of Physics, Indian Institute of Science , Bengaluru 560012, India
| | - Bappaditya Chandra
- Department of Chemical Sciences, Tata Institute of Fundamental Research , Homi Bhabha Road, Colaba, Mumbai 400005, India
| | - Jaydeep K Basu
- Department of Physics, Indian Institute of Science , Bengaluru 560012, India
| | - Gilbert C Walker
- Department of Chemistry, Lash Miller Laboratories, University of Toronto , Toronto, ON M5S 3H6, Canada
| | - Perunthiruthy K Madhu
- Department of Chemical Sciences, Tata Institute of Fundamental Research , Homi Bhabha Road, Colaba, Mumbai 400005, India
- TIFR Centre for Interdisciplinary Sciences , 21 Brundavan Colony, Narsinghi, Hyderabad 500075, India
| | - Sudipta Maiti
- Department of Chemical Sciences, Tata Institute of Fundamental Research , Homi Bhabha Road, Colaba, Mumbai 400005, India
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28
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Zhao LN, Zheng J, Chew LY, Mu Y. An Investigation on the Fundamental Interaction between Abeta Peptides and the AT-Rich DNA. J Phys Chem B 2015; 119:8247-59. [PMID: 26086541 DOI: 10.1021/acs.jpcb.5b00957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
DNA damage is ubiquitous in all mammalian cells with the occurrence of more than 60,000 times per day per cell. In particular, DNA damage in neurons is found to accumulate with age and has been suggested to interfere with the synthesis of functional proteins. Moreover, recent studies have found through transgenic mice that human amyloid precursor protein causes an increase in DNA double-strand breaks (DSBs) with the effect of a prolongation in DNA repair. It is surmised that amyloid β (Aβ) exacerbates the DNA DSBs in neurons, possibly engendering neuronal dysfunction as a result. However, a good understanding on the holistic interaction mechanisms and the manner in which Aβ intertwines with DNA damage is still in its infancy. In our study, we found that DNA with an AT-rich sequence has a very low binding affinity toward Aβ by means of molecular dynamics simulation. While we have pursued a particular sequence of DNA in this study, other DNA sequences are expected to affect the interaction and binding affinity between DNA and Aβ, and will be pursued in our further research. Nonetheless, we have uncovered favorable interaction between the positively charged side chain of Aβ and the two ends of DNA. The latest experiment reveals that many of the double-stranded breaks in neurons can be fixed via DNA repair mechanisms but not in the case that Aβs are present. It is found that the increased numbers of DSBs prevail in active neurons. Here, on the basis of the favorable interaction between Aβ and the two ends of DNA, we propose the possibility that Aβ prevents DNA repair via binding directly to the break ends of the DNA, which further exacerbates DNA damage. Moreover, we have found that the base pair oxygen of the DNA has a greater preference to form hydrogen bonds than the backbone oxygen with Aβ at the two ends. Thus, we postulate that Aβ could serve to prevent the repair of AT-rich DNA, and it is unlikely to cause its breakage or affect its binding toward histone. Another important observation from our study is that AT-rich DNA has very little or no influence on Aβ oligomerization. Finally, even though we do not observe any dramatic DNA conformational change in the presence of Aβ, we do observe an increase in diversity of the DNA structural parameters such as groove width, local base step, and torsional angles in lieu of Aβ interactions.
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Affiliation(s)
- Li Na Zhao
- †School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore.,‡School of Computer Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore.,§Bioinformatics Institute, 30 Biopolis Street, Singapore 138671
| | - Jie Zheng
- ‡School of Computer Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore.,∥Genome Institute of Singapore, A* STAR, 60 Biopolis Street, Singapore 138672
| | - Lock Yue Chew
- †School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore.,⊥Complexity Institute, Nanyang Technological University, 18 Nanyang Drive, Singapore
| | - Yuguang Mu
- #School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore
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29
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Cheon M, Hall CK, Chang I. Structural Conversion of Aβ17-42 Peptides from Disordered Oligomers to U-Shape Protofilaments via Multiple Kinetic Pathways. PLoS Comput Biol 2015; 11:e1004258. [PMID: 25955249 PMCID: PMC4425657 DOI: 10.1371/journal.pcbi.1004258] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 03/29/2015] [Indexed: 11/18/2022] Open
Abstract
Discovering the mechanisms by which proteins aggregate into fibrils is an essential first step in understanding the molecular level processes underlying neurodegenerative diseases such as Alzheimer's and Parkinson's. The goal of this work is to provide insights into the structural changes that characterize the kinetic pathways by which amyloid-β peptides convert from monomers to oligomers to fibrils. By applying discontinuous molecular dynamics simulations to PRIME20, a force field designed to capture the chemical and physical aspects of protein aggregation, we have been able to trace out the entire aggregation process for a system containing 8 Aβ17-42 peptides. We uncovered two fibrillization mechanisms that govern the structural conversion of Aβ17-42 peptides from disordered oligomers into protofilaments. The first mechanism is monomeric conversion templated by a U-shape oligomeric nucleus into U-shape protofilament. The second mechanism involves a long-lived and on-pathway metastable oligomer with S-shape chains, having a C-terminal turn, en route to the final U-shape protofilament. Oligomers with this C-terminal turn have been regarded in recent experiments as a major contributing element to cell toxicity in Alzheimer's disease. The internal structures of the U-shape protofilaments from our PRIME20/DMD simulation agree well with those from solid state NMR experiments. The approach presented here offers a simple molecular-level framework to describe protein aggregation in general and to visualize the kinetic evolution of a putative toxic element in Alzheimer's disease in particular.
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Affiliation(s)
- Mookyung Cheon
- Center for Proteome Biophysics, Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Carol K. Hall
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail: (CKH); (IC)
| | - Iksoo Chang
- Center for Proteome Biophysics, Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
- * E-mail: (CKH); (IC)
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30
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31
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Zhang M, Zhao J, Zheng J. Molecular understanding of a potential functional link between antimicrobial and amyloid peptides. SOFT MATTER 2014; 10:7425-7451. [PMID: 25105988 DOI: 10.1039/c4sm00907j] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Antimicrobial and amyloid peptides do not share common sequences, typical secondary structures, or normal biological activity but both the classes of peptides exhibit membrane-disruption ability to induce cell toxicity. Different membrane-disruption mechanisms have been proposed for antimicrobial and amyloid peptides, individually, some of which are not exclusive to either peptide type, implying that certain common principles may govern the folding and functions of different cytolytic peptides and associated membrane disruption mechanisms. Particularly, some antimicrobial and amyloid peptides have been identified to have dual complementary amyloid and antimicrobial properties, suggesting a potential functional link between amyloid and antimicrobial peptides. Given that some similar structural and membrane-disruption characteristics exist between the two classes of peptides, this review summarizes major findings, recent advances, and future challenges related to antimicrobial and amyloid peptides and strives to illustrate the similarities, differences, and relationships in the sequences, structures, and membrane interaction modes between amyloid and antimicrobial peptides, with a special focus on direct interactions of the peptides with the membranes. We hope that this review will stimulate further research at the interface of antimicrobial and amyloid peptides - which has been studied less intensively than either type of peptides - to decipher a possible link between both amyloid pathology and antimicrobial activity, which can guide drug design and peptide engineering to influence peptide-membrane interactions important in human health and diseases.
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Affiliation(s)
- Mingzhen Zhang
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, USA.
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32
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Jang H, Arce FT, Ramachandran S, Kagan BL, Lal R, Nussinov R. Disordered amyloidogenic peptides may insert into the membrane and assemble into common cyclic structural motifs. Chem Soc Rev 2014; 43:6750-64. [PMID: 24566672 PMCID: PMC4143503 DOI: 10.1039/c3cs60459d] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Aggregation of disordered amyloidogenic peptides into oligomers is the causative agent of amyloid-related diseases. In solution, disordered protein states are characterized by heterogeneous ensembles. Among these, β-rich conformers self-assemble via a conformational selection mechanism to form energetically-favored cross-β structures, regardless of their precise sequences. These disordered peptides can also penetrate the membrane, and electrophysiological data indicate that they form ion-conducting channels. Based on these and additional data, including imaging and molecular dynamics simulations of a range of amyloid peptides, Alzheimer's amyloid-β (Aβ) peptide, its disease-related variants with point mutations and N-terminal truncated species, other amyloidogenic peptides, as well as a cytolytic peptide and a synthetic gel-forming peptide, we suggest that disordered amyloidogenic peptides can also present a common motif in the membrane. The motif consists of curved, moon-like β-rich oligomers associated into annular organizations. The motif is favored in the lipid bilayer since it permits hydrophobic side chains to face and interact with the membrane and the charged/polar residues to face the solvated channel pores. Such channels are toxic since their pores allow uncontrolled leakage of ions into/out of the cell, destabilizing cellular ionic homeostasis. Here we detail Aβ, whose aggregation is associated with Alzheimer's disease (AD) and for which there are the most abundant data. AD is a protein misfolding disease characterized by a build-up of Aβ peptide as senile plaques, neurodegeneration, and memory loss. Excessively produced Aβ peptides may directly induce cellular toxicity, even without the involvement of membrane receptors through Aβ peptide-plasma membrane interactions.
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Affiliation(s)
- Hyunbum Jang
- Cancer and Inflammation Program, National Cancer Institute at Frederick, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, U.S.A
| | - Fernando Teran Arce
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, U.S.A
| | - Srinivasan Ramachandran
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, U.S.A
| | - Bruce L. Kagan
- Department of Psychiatry, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, California 90024, U.S.A
| | - Ratnesh Lal
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, U.S.A
| | - Ruth Nussinov
- Cancer and Inflammation Program, National Cancer Institute at Frederick, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, U.S.A
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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33
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Kotler SA, Walsh P, Brender JR, Ramamoorthy A. Differences between amyloid-β aggregation in solution and on the membrane: insights into elucidation of the mechanistic details of Alzheimer's disease. Chem Soc Rev 2014; 43:6692-700. [PMID: 24464312 PMCID: PMC4110197 DOI: 10.1039/c3cs60431d] [Citation(s) in RCA: 301] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The association of the amyloid-β (Aβ) peptide with cellular membranes is hypothesized to be the underlying phenomenon of neurotoxicity in Alzheimer's disease. Misfolding of proteins and peptides, as is the case with Aβ, follows a progression from a monomeric state, through intermediates, ending at long, unbranched amyloid fibers. This tutorial review offers a perspective on the association of toxic Aβ structures with membranes as well as details of membrane-associated mechanisms of toxicity.
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Affiliation(s)
- Samuel A Kotler
- Biophysics and Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, MI 48109-1055, USA.
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34
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Zhao J, Hu R, Sciacca MFM, Brender JR, Chen H, Ramamoorthy A, Zheng J. Non-selective ion channel activity of polymorphic human islet amyloid polypeptide (amylin) double channels. Phys Chem Chem Phys 2014; 16:2368-77. [PMID: 24352606 DOI: 10.1039/c3cp53345j] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fundamental understanding of ion channel formation by amyloid peptides, which is strongly linked to cell toxicity, is very critical for (pre)clinical treatment of neurodegenerative diseases. Here, we combine atomistic simulations and experiments to demonstrate a broad range of conformational states of hIAPP double channels in lipid membranes. All individual channels display high selectivity for Cl(-) ions over cations, but the co-existence of polymorphic double channels of different conformations and orientations with different populations determines the non-ionic selectivity nature of the channels, which is different from the typical amyloid-β channels that exhibit Ca(2+) selective ion-permeable characteristics. This work provides a more complete physicochemical mechanism of amyloid-channel-induced toxicity.
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Affiliation(s)
- Jun Zhao
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA.
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35
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Di Scala C, Chahinian H, Yahi N, Garmy N, Fantini J. Interaction of Alzheimer's β-amyloid peptides with cholesterol: mechanistic insights into amyloid pore formation. Biochemistry 2014; 53:4489-502. [PMID: 25000142 DOI: 10.1021/bi500373k] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Brain cholesterol plays a critical role in Alzheimer's disease and other neurodegenerative diseases. The molecular mechanisms linking cholesterol to neurotoxicity have remained elusive for a long time, but recent data have allowed the identification of functional cholesterol-binding domains in several amyloidogenic proteins involved in neurodegenerative diseases, including Alzheimer's disease. In this review, we analyze the cholesterol binding properties of β-amyloid (Aβ) peptides and the impact of these interactions on amyloid pore formation. We show that although the cholesterol-binding domains of Aβ peptides and of transmembrane precursor C99 are partially overlapping, they involve distinct amino acid residues, so that cholesterol has a greater affinity for Aβ than for C99. Synthetic 22-35 and 25-35 fragments of Aβ retained the ability of the full-length peptide 1-42 to bind cholesterol and to form zinc-sensitive, calcium-permeable amyloid pores in cultured neural cells. Studies with mutant peptides allowed the identification of key residues involved in cholesterol binding and channel formation. Cholesterol promoted the insertion of Aβ in the plasma membrane, induced α-helical structuration, and forced the peptide to adopt a tilted topology that favored the oligomerization process. Bexarotene, an amphipathic drug currently considered as a potential candidate medication for the treatment of neurodegenerative diseases, competed with cholesterol for binding to Aβ and prevented oligomeric channel formation. These studies indicate that it is possible to prevent the generation of neurotoxic oligomers by targeting the cholesterol-binding domain of Aβ peptides. This original strategy could be used for the treatment of Alzheimer's and other neurodegenerative diseases that involve cholesterol-dependent toxic oligomers.
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Affiliation(s)
- Coralie Di Scala
- EA-4674, Faculté des Sciences de Saint-Jérôme, Aix-Marseille Université , 13013 Marseille, France
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36
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Poojari C, Xiao D, Batista VS, Strodel B. Membrane permeation induced by aggregates of human islet amyloid polypeptides. Biophys J 2014; 105:2323-32. [PMID: 24268144 DOI: 10.1016/j.bpj.2013.09.045] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 09/12/2013] [Accepted: 09/30/2013] [Indexed: 01/23/2023] Open
Abstract
Several neurodegenerative diseases such as Alzheimer's and Parkinson's diseases as well as nonneuropathic diseases such as type II diabetes and atrial amyloidosis are associated with aggregation of amyloid polypeptides into fibrillar structures, or plaques. In this study, we use molecular dynamics simulations to test the stability and orientation of membrane-embedded aggregates of the human islet amyloid polypeptide (hIAPP) implicated in type II diabetes. We find that in both monolayers and bilayers of dipalmitoylphosphatidylglycerol (DPPG) hIAPP trimers and tetramers remain inside the membranes and preserve their β-sheet secondary structure. Lipid bilayer-inserted hIAPP trimers and tetramers orient inside DPPG at 60° relative to the membrane/water interface and lead to water permeation and Na(+) intrusion, consistent with ion-toxicity in islet β-cells. In particular, hIAPP trimers form a water-filled β-sandwich that induce water permeability comparable with channel-forming proteins, such as aquaporins and gramicidin-A. The predicted disruptive orientation is consistent with the amphiphilic properties of the hIAPP aggregates and could be probed by chiral sum frequency generation (SFG) spectroscopy, as predicted by the simulated SFG spectra.
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Affiliation(s)
- Chetan Poojari
- Forschungszentrum Jülich GmbH, Institute of Complex Systems: Structural Biochemistry (ICS-6), 52425 Jülich, Germany
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37
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Lee J, Gillman AL, Jang H, Ramachandran S, Kagan BL, Nussinov R, Teran Arce F. Role of the fast kinetics of pyroglutamate-modified amyloid-β oligomers in membrane binding and membrane permeability. Biochemistry 2014; 53:4704-14. [PMID: 24950761 PMCID: PMC4215883 DOI: 10.1021/bi500587p] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
![]()
Membrane
permeability to ions and small molecules is believed to
be a critical step in the pathology of Alzheimer’s disease
(AD). Interactions of oligomers formed by amyloid-β (Aβ)
peptides with the plasma cell membrane are believed to play a fundamental
role in the processes leading to membrane permeability. Among the
family of Aβs, pyroglutamate (pE)-modified Aβ peptides
constitute the most abundant oligomeric species in the brains of AD
patients. Although membrane permeability mechanisms have been studied
for full-length Aβ1–40/42 peptides, these
have not been sufficiently characterized for the more abundant AβpE3–42 fragment. Here we have compared the adsorbed
and membrane-inserted oligomeric species of AβpE3–42 and Aβ1–42 peptides. We find lower concentrations
and larger dimensions for both species of membrane-associated AβpE3–42 oligomers. The larger dimensions are attributed
to the faster self-assembly kinetics of AβpE3–42, and the lower concentrations are attributed to weaker interactions
with zwitterionic lipid headgroups. While adsorbed oligomers produced
little or no significant membrane structural damage, increased membrane
permeabilization to ionic species is understood in terms of enlarged
membrane-inserted oligomers. Membrane-inserted AβpE3–42 oligomers were also found to modify the mechanical properties of
the membrane. Taken together, our results suggest that membrane-inserted
oligomers are the primary species responsible for membrane permeability.
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Affiliation(s)
- Joon Lee
- Department of Bioengineering, University of California at San Diego , La Jolla, California 92093, United States
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38
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Gillman AL, Jang H, Lee J, Ramachandran S, Kagan B, Nussinov R, Teran Arce F. Activity and architecture of pyroglutamate-modified amyloid-β (AβpE3-42) pores. J Phys Chem B 2014; 118:7335-44. [PMID: 24922585 PMCID: PMC4096221 DOI: 10.1021/jp5040954] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 06/10/2014] [Indexed: 12/17/2022]
Abstract
Among the family of Aβ peptides, pyroglutamate-modified Aβ (AβpE) peptides are particularly associated with cytotoxicity in Alzheimer's disease (AD). They represent the dominant fraction of Aβ oligomers in the brains of AD patients, but their accumulation in the brains of elderly individuals with normal cognition is significantly lower. Accumulation of AβpE plaques precedes the formation of plaques of full-length Aβ (Aβ1-40/42). Most of these properties appear to be associated with the higher hydrophobicity of AβpE as well as an increased resistance to enzymatic degradation. However, the important question of whether AβpE peptides induce pore activity in lipid membranes and their potential toxicity compared with other Aβ pores is still open. Here we examine the activity of AβpE pores in anionic membranes using planar bilayer electrical recording and provide their structures using molecular dynamics simulations. We find that AβpE pores spontaneously induce ionic current across the membrane and have some similar properties to the other previously studied pores of the Aβ family. However, there are also some significant differences. The onset of AβpE3-42 pore activity is generally delayed compared with Aβ1-42 pores. However, once formed, AβpE3-42 pores produce increased ion permeability of the membrane, as indicated by a greater occurrence of higher conductance electrical events. Structurally, the lactam ring of AβpE peptides induces a change in the conformation of the N-terminal strands of the AβpE3-42 pores. While the N-termini of wild-type Aβ1-42 peptides normally reside in the bulk water region, the N-termini of AβpE3-42 peptides tend to reside in the hydrophobic lipid core. These studies provide a first step to an understanding of the enhanced toxicity attributed to AβpE peptides.
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Affiliation(s)
- Alan L. Gillman
- Department
of Bioengineering, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
| | - Hyunbum Jang
- Cancer
and Inflammation Program, National Cancer Institute at Frederick,
Leidos Biomedical Research, Inc., Frederick
National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Joon Lee
- Department
of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Srinivasan Ramachandran
- Department
of Bioengineering, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
- Department
of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Bruce
L. Kagan
- Department
of Psychiatry, David Geffen School of Medicine, Semel Institute for
Neuroscience and Human Behavior, University
of California, 760 Westwood
Plaza, Los Angeles, California 90024, United States
| | - Ruth Nussinov
- Cancer
and Inflammation Program, National Cancer Institute at Frederick,
Leidos Biomedical Research, Inc., Frederick
National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
- Department
of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Fernando Teran Arce
- Department
of Bioengineering, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
- Department
of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
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39
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Pobandt T, Knecht V. Free energy of lipid bilayer defects affected by Alzheimer's disease-associated amyloid-β42 monomers. J Phys Chem B 2014; 118:3507-16. [PMID: 24597727 DOI: 10.1021/jp410477x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Experimental evidence suggests that the amyloid β-peptide (Aβ) associated with Alzheimer's disease strongly disturbs the integrity of lipid bilayers and cell membranes, as a possible origin of the toxicity of this peptide. Here, we have used molecular dynamics simulations to compute the free energy of membrane pores in the presence and absence of Aβ. The validation of our approach included the calculation of lipid flip-flop waiting times, which were found to agree well with recent experiments, in contrast with an earlier simulation study that apparently overestimated these waiting times. We find that, compared with peptide-free lipid bilayers, attached Aβ42 peptides (i) increase the order parameters of the lipid tails but (ii) decrease the effective width of the hydrophobic region, (iii) reduce the free energy and thus enlarge the density of membrane pores, and (iv) increase the lifetime of pores. A detailed understanding of the interaction of Aβ42 with lipid bilayer membranes may assist in the design of therapeutical strategies against Alzheimer's disease.
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Affiliation(s)
- Tobias Pobandt
- Theory & Bio-Systems, Max Planck Institute of Colloids and Interfaces , Science Park Golm, D-14424 Potsdam, Germany
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40
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Cellular membrane fluidity in amyloid precursor protein processing. Mol Neurobiol 2014; 50:119-29. [PMID: 24553856 DOI: 10.1007/s12035-014-8652-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 01/23/2014] [Indexed: 12/20/2022]
Abstract
The senile plaque is a pathologic hallmark of Alzheimer's disease (AD). Amyloid-β peptide (Aβ), the main constituent of senile plaques, is neurotoxic especially in its oligomeric form. Aβ is derived from the sequential cleavage of amyloid precursor protein (APP) by β- and γ-secretases in the amyloidogenic pathway. Alternatively, APP can be cleaved by α-secretases within the Aβ domain to produce neurotrophic and neuroprotective α-secretase-cleaved soluble APP (sAPPα) in the nonamyloidogenic pathway. Since APP and α-, β-, and γ-secretases are membrane proteins, APP processing should be highly dependent on the membrane composition and the biophysical properties of cellular membrane. In this review, we discuss the role of the biophysical properties of cellular membrane in APP processing, especially the effects of phospholipases A(2) (PLA(2)s), fatty acids, cholesterol, and Aβ on membrane fluidity in relation to their effects on APP processing.
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41
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Zhang H, Griggs A, Rochet JC, Stanciu LA. In vitro study of α-synuclein protofibrils by cryo-EM suggests a Cu(2+)-dependent aggregation pathway. Biophys J 2014; 104:2706-13. [PMID: 23790379 DOI: 10.1016/j.bpj.2013.04.050] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 04/16/2013] [Accepted: 04/23/2013] [Indexed: 01/25/2023] Open
Abstract
The aggregation of α-synuclein is thought to play a role in the death of dopamine neurons in Parkinson's disease (PD). Alpha-synuclein transitions itself through an aggregation pathway consisting of pathogenic species referred to as protofibrils (or oligomer), which ultimately convert to mature fibrils. The structural heterogeneity and instability of protofibrils has significantly impeded advance related to the understanding of their structural characteristics and the amyloid aggregation mystery. Here, we report, to our knowledge for the first time, on α-synuclein protofibril structural characteristics with cryo-electron microscopy. Statistical analysis of annular protofibrils revealed a constant wall thickness as a common feature. The visualization of the assembly steps enabled us to propose a novel, to our knowledge, mechanisms for α-synuclein aggregation involving ring-opening and protofibril-protofibril interaction events. The ion channel-like protofibrils and their membrane permeability have also been found in other amyloid diseases, suggesting a common molecular mechanism of pathological aggregation. Our direct visualization of the aggregation pathway of α-synuclein opens up fresh opportunities to advance the understanding of protein aggregation mechanisms relevant to many amyloid diseases. In turn, this information would enable the development of additional therapeutic strategies aimed at suppressing toxic protofibrils of amyloid proteins involved in neurological disorders.
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Affiliation(s)
- Hangyu Zhang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana, USA
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Kim Y, Li W, Shin S, Lee M. Development of toroidal nanostructures by self-assembly: rational designs and applications. Acc Chem Res 2013; 46:2888-97. [PMID: 24053785 DOI: 10.1021/ar400027c] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Toroidal nanostructures are symmetrical ring-shaped structures with a central internal pore. Interestingly, in nature, many transmembrane proteins such as β-barrels and α-helical bundles have toroidal shapes. Because of this similarity, toroidal nanostructures can provide a template for the development of transmembrane channels. However, because of the lack of guiding principles for the construction of toroids, researchers have not widely studied the self-assembly of toroidal nanostructures as compared with the work on other supramolecular architectures. In this Account, we describe our recent efforts to construct toroidal nanostructures through the self-assembly of rationally designed building blocks. In one strategy for building these structures, we induce interfacial curvatures within the building blocks. When we laterally graft a bulky hydrophilic segment onto a p-oligophenyl rod or β-sheet peptides, the backbones of the self-assembled structures can bend in response to the steric effect of these large side groups, driving the p-oligophenyl rod or β-sheet peptides to form nanosized toriods. In another strategy, we can build toroids from bent-shaped building blocks by stacking the macrocycles. Aromatic segments with an internal angle of 120° can associate with each other in aqueous solution to form a hexameric macrocycle. Then these macrocycles can stack on top of each other via hydrophobic and π-π interactions and form highly uniform toroidal nanostructures. We provide many examples that illustrate these guiding principles for constructing toroidal nanostructures in aqueous solution. Efforts to create toroidal nanostructures through the self-assembly of elaborately designed molecular modules provide a fundamental approach toward the development of artificial transmembrane channels. Among the various toroids that we developed, a few nanostructures can insert into lipid membranes and allow limited transport in vesicles.
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Affiliation(s)
- Yongju Kim
- State Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
| | - Wen Li
- State Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
| | - Suyong Shin
- Department of Chemistry, Seoul National University, Seoul 151-747, Korea
| | - Myongsoo Lee
- State Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
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Poojari C, Strodel B. Stability of transmembrane amyloid β-peptide and membrane integrity tested by molecular modeling of site-specific Aβ42 mutations. PLoS One 2013; 8:e78399. [PMID: 24244308 PMCID: PMC3820573 DOI: 10.1371/journal.pone.0078399] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 09/11/2013] [Indexed: 11/20/2022] Open
Abstract
Interactions of the amyloid β-protein (Aβ) with neuronal cell membranes, leading to the disruption of membrane integrity, are considered to play a key role in the development of Alzheimer’s disease. Natural mutations in Aβ42, such as the Arctic mutation (E22G) have been shown to increase Aβ42 aggregation and neurotoxicity, leading to the early-onset of Alzheimer’s disease. A correlation between the propensity of Aβ42 to form protofibrils and its effect on neuronal dysfunction and degeneration has been established. Using rational mutagenesis of the Aβ42 peptide it was further revealed that the aggregation of different Aβ42 mutants in lipid membranes results in a variety of polymorphic aggregates in a mutation dependent manner. The mutant peptides also have a variable ability to disrupt bilayer integrity. To further test the connection between Aβ42 mutation and peptide–membrane interactions, we perform molecular dynamics simulations of membrane-inserted Aβ42 variants (wild-type and E22G, D23G, E22G/D23G, K16M/K28M and K16M/E22G/D23G/K28M mutants) as β-sheet monomers and tetramers. The effects of charged residues on transmembrane Aβ42 stability and membrane integrity are analyzed at atomistic level. We observe an increased stability for the E22G Aβ42 peptide and a decreased stability for D23G compared to wild-type Aβ42, while D23G has the largest membrane-disruptive effect. These results support the experimental observation that the altered toxicity arising from mutations in Aβ is not only a result of the altered aggregation propensity, but also originates from modified Aβ interactions with neuronal membranes.
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Affiliation(s)
- Chetan Poojari
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich GmbH, Jülich, Germany
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- * E-mail:
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Gupta K, Jang H, Harlen K, Puri A, Nussinov R, Schneider JP, Blumenthal R. Mechanism of membrane permeation induced by synthetic β-hairpin peptides. Biophys J 2013; 105:2093-103. [PMID: 24209854 PMCID: PMC3824417 DOI: 10.1016/j.bpj.2013.09.040] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/23/2013] [Accepted: 09/26/2013] [Indexed: 11/16/2022] Open
Abstract
We have investigated the membrane destabilizing properties of synthetic amphiphilic cationic peptides, MAX1 and MAX35, which have the propensity to form β-hairpin structures under certain conditions, and a control non-β-hairpin-forming peptide MAX8V16E. All three peptides bind to liposomes containing a mixture of zwitterionic POPC and negatively charged POPS lipids as determined by Zeta potential measurements. Circular dichroism measurements indicated folding of MAX1 and MAX35 in the presence of the POPC/POPS liposomes, whereas no such folding was observed with MAX8V16E. There was no binding or folding of these peptides to liposomes containing only POPC. MAX1 and MAX35 induced release of contents from negatively charged liposomes, whereas MAX8V16E failed to promote solute release under identical conditions. Thus, MAX1 and MAX35 bind to, and fold at the surface of negatively charged liposomes adopting a lytic conformation. We ruled out leaky fusion as a mechanism of release by including 2 mol % PEG-PE in the liposomes, which inhibits aggregation/fusion but not folding of MAX or MAX-induced leakage. Using a concentration-dependent quenching probe (calcein), we determined that MAX-induced leakage of liposome contents was an all-or-none process. At MAX1 concentrations, which cause release of ~50% of the liposomes that contain small (R(h) <1.5 nm) markers, only ~15% of those liposomes release a fluorescent dextran of 40 kDa. A multimeric model of the pore is presented based on these results. Atomistic molecular dynamics simulations show that barrels consisting of 10 β-hairpin MAX1 and MAX35 peptides are relatively more stable than MAX8V16E barrels in the bilayer, suggesting that barrels of this size are responsible for the peptides lytic action.
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Affiliation(s)
- Kshitij Gupta
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Hyunbum Jang
- Basic Science Program, SAIC-Frederick, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Kevin Harlen
- Peptide Design and Materials Section, Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Anu Puri
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Ruth Nussinov
- Basic Science Program, SAIC-Frederick, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Joel P. Schneider
- Peptide Design and Materials Section, Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, Maryland
| | - Robert Blumenthal
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland
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45
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Jang H, Arce FT, Ramachandran S, Kagan BL, Lal R, Nussinov R. Familial Alzheimer's disease Osaka mutant (ΔE22) β-barrels suggest an explanation for the different Aβ1-40/42 preferred conformational states observed by experiment. J Phys Chem B 2013; 117:11518-29. [PMID: 24000923 PMCID: PMC3946471 DOI: 10.1021/jp405389n] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An unusual ΔE693 mutation in the amyloid precursor protein (APP) producing a β-amyloid (Aβ) peptide lacking glutamic acid at position 22 (Glu22) was recently discovered, and dabbed the Osaka mutant (ΔE22). Previously, several point mutations in the Aβ peptide involving Glu22 substitutions were identified and implicated in the early onset of familial Alzheimer's disease (FAD). Despite the absence of Glu22, the Osaka mutant is also associated with FAD, showing a recessive inheritance in families affected by the disease. To see whether this aggregation-prone Aβ mutant could directly relate to the Aβ ion channel-mediated mechanism as observed for the wild type (WT) Aβ peptide in AD pathology, we modeled Osaka mutant β-barrels in a lipid bilayer. Using molecular dynamics (MD) simulations, two conformer ΔE22 barrels with the U-shaped monomer conformation derived from NMR-based WT Aβ fibrils were simulated in explicit lipid environment. Here, we show that the ΔE22 barrels obtain the lipid-relaxed β-sheet channel topology, indistinguishable from the WT Aβ1-42 barrels, as do the outer and pore dimensions of octadecameric (18-mer) ΔE22 barrels. Although the ΔE22 barrels lose the cationic binding site in the pore which is normally provided by the negatively charged Glu22 side chains, the mutant pores gain a new cationic binding site by Glu11 at the lower bilayer leaflet, and exhibit ion fluctuations similar to the WT barrels. Of particular interest, this deletion mutant suggests that toxic WT Aβ1-42 would preferentially adopt a less C-terminal turn similar to that observed for Aβ17-42, and explains why the solid state NMR data for Aβ1-40 point to a more C-terminal turn conformation. The observed ΔE22 barrels conformational preferences also suggest an explanation for the lower neurotoxicity in rat primary neurons as compared to WT Aβ1-42.
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Affiliation(s)
- Hyunbum Jang
- Basic Science Program, SAIC-Frederick, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, USA
| | - Fernando Teran Arce
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Srinivasan Ramachandran
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Bruce L. Kagan
- Department of Psychiatry, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, California 90024, USA
| | - Ratnesh Lal
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, USA
| | - Ruth Nussinov
- Basic Science Program, SAIC-Frederick, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, USA
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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Peters C, Fernandez-Perez EJ, Burgos CF, Espinoza MP, Castillo C, Urrutia JC, Streltsov VA, Opazo C, Aguayo LG. Inhibition of amyloid beta-induced synaptotoxicity by a pentapeptide derived from the glycine zipper region of the neurotoxic peptide. Neurobiol Aging 2013; 34:2805-14. [PMID: 23855983 DOI: 10.1016/j.neurobiolaging.2013.06.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 05/29/2013] [Accepted: 06/04/2013] [Indexed: 10/26/2022]
Abstract
A major characteristic of Alzheimer's disease is the presence of amyloid beta (Aβ) oligomers and aggregates in the brain. Aβ oligomers interact with the neuronal membrane inducing perforations, causing an influx of calcium ions and increasing the release of synaptic vesicles that leads to a delayed synaptic failure by vesicle depletion. Here, we identified a neuroprotective pentapeptide anti-Aβ compound having the sequence of the glycine zipper region of the C-terminal of Aβ (G33LMVG37). Docking and Förster resonance energy transfer experiments showed that G33LMVG37 interacts with Aβ at the C-terminal region, which is important for Aβ association and insertion into the lipid membrane. Furthermore, this pentapeptide interfered with Aβ aggregation, association, and perforation of the plasma membrane. The synaptotoxicity induced by Aβ after acute and chronic applications were abolished by G33LMVG37. These results provide a novel rationale for drug development against Alzheimer's disease.
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Affiliation(s)
- Christian Peters
- Laboratory of Neurophysiology, Department of Physiology, University of Concepción, Concepción, Chile; Laboratory of Neurobiometals, Department of Physiology, University of Concepción, Concepción, Chile
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47
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Jang H, Connelly L, Arce FT, Ramachandran S, Lal R, Kagan BL, Nussinov R. Alzheimer's disease: which type of amyloid-preventing drug agents to employ? Phys Chem Chem Phys 2013; 15:8868-77. [PMID: 23450150 PMCID: PMC3663909 DOI: 10.1039/c3cp00017f] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The current paradigm in the amyloid hypothesis brands small β-amyloid (Aβ) oligomers as the toxic species in Alzheimer's disease (AD). These oligomers are fibril-like; contain β-sheet structure, and present exposed hydrophobic surface. Oligomers with this motif are capable of penetrating the cell membrane, gathering to form toxic ion channels. Current agents suppressing precursor Aβ cleavage have only met partial success; and to date, those targeting the peptides and their assemblies in the aqueous environment of the extracellular space largely fail in clinical trials. One possible reason is failure to reach membrane-embedded targets of disease-'infected' cells. Here we provide an overview, point to the need to account for the lipid environment when aiming to prevent the formation of toxic channels, and propose a combination therapy to target the species spectrum.
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Affiliation(s)
- Hyunbum Jang
- Center for Cancer Research, Nanobiology Program, Basic Science Program, SAIC-Frederick, Inc., National Cancer Institute, Frederick, Maryland 21702, USA
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48
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Prada I, Furlan R, Matteoli M, Verderio C. Classical and unconventional pathways of vesicular release in microglia. Glia 2013; 61:1003-17. [PMID: 23625857 DOI: 10.1002/glia.22497] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 02/22/2013] [Indexed: 12/30/2022]
Abstract
Emerging evidence indicates that activation of microglia, the immune cells of the brain, is strictly associated to both secretion of soluble molecules and release of extracellular membrane vesicles (EMVs) into the pericellular space. Through these processes, microglia heavily influence brain cell functions, either propagating inflammation and causing damage to neurons or playing a supportive, neuroprotective role. In this review, we highlight the emerging concepts related to vesicular mechanisms of secretion operating in microglial cells, with the aim of dissecting how microglia communicate with other cell types within the brain microenvironment in health and disease.
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Affiliation(s)
- Ilaria Prada
- Humanitas Clinical and Research Center, Rozzano (MI), Italy
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49
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Yu X, Wang Q, Pan Q, Zhou F, Zheng J. Molecular interactions of Alzheimer amyloid-β oligomers with neutral and negatively charged lipid bilayers. Phys Chem Chem Phys 2013; 15:8878-89. [PMID: 23493873 DOI: 10.1039/c3cp44448a] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Interaction of p3 (Aβ(17-42)) peptides with cell membranes is crucial for the understanding of amyloid toxicity associated with Alzheimer's disease (AD). Such p3-membrane interactions are considered to induce the disruption of membrane permeability and integrity, but the exact mechanisms of how p3 aggregates, particularly small p3 oligomers, induce receptor-independent membrane disruption are not yet completely understood. Here, we investigate the adsorption, orientation, and surface interaction of the p3 pentamer with lipid bilayers composed of both pure zwitterionic POPC (palmitoyl-oleoyl-phosphatidylcholine) and mixed anionic POPC-POPG (palmitoyl-oleoyl-phosphatidylglycerol) (3 : 1) lipids using explicit-solvent molecular dynamics (MD) simulations. MD simulation results show that the p3 pentamer has much stronger interactions with mixed POPC-POPG lipids than pure POPC lipids, consistent with experimental observation that Aβ adsorption and fibrillation are enhanced on anionic lipid bilayers. Although electrostatic interactions are main attractive forces to drive the p3 pentamer to adsorb on the bilayer surface, the adsorption of the p3 pentamer on the lipid bilayer with C-terminal β-strands facing toward the bilayer surface is a net outcome of different competitions between p3 peptides-lipid bilayer and ions-p3-bilayer interactions. More importantly, Ca(2+) ions are found to form ionic bridges to associate negatively charged residues of p3 with anionic headgroups of the lipid bilayer, resulting in Aβ-Ca(2+)-PO4(-) complexes. Intensive Ca(2+) bound to the lipid bilayer and Ca(2+) ionic bridges may lead to Ca(2+) hemostasis responsible for neuronal dysfunction and death. This work provides insights into the mutual structure, dynamics, and interactions of both Aβ peptides and lipid bilayers at the atomic level, which expand our understanding of the complex behavior of amyloid-induced membrane disruption.
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Affiliation(s)
- Xiang Yu
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA
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50
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Sirangelo I, Irace G, Balestrieri ML. Amyloid toxicity and platelet-activating factor signaling. J Cell Physiol 2013; 228:1143-8. [DOI: 10.1002/jcp.24284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 11/07/2012] [Indexed: 01/08/2023]
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