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Lau D, Tang Y, Kenche V, Copie T, Kempe D, Jary E, Graves NJ, Biro M, Masters CL, Dzamko N, Gambin Y, Sierecki E. Single-Molecule Fingerprinting Reveals Different Growth Mechanisms in Seed Amplification Assays for Different Polymorphs of α-Synuclein Fibrils. ACS Chem Neurosci 2024. [PMID: 39197832 DOI: 10.1021/acschemneuro.4c00185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2024] Open
Abstract
α-Synuclein (αSyn) aggregates, detected in the biofluids of patients with Parkinson's disease (PD), have the ability to catalyze their own aggregation, leading to an increase in the number and size of aggregates. This self-templated amplification is used by newly developed assays to diagnose Parkinson's disease and turns the presence of αSyn aggregates into a biomarker of the disease. It has become evident that αSyn can form fibrils with slightly different structures, called "strains" or polymorphs, but little is known about their differential reactivity in diagnostic assays. Here, we compared the properties of two well-described αSyn polymorphs. Using single-molecule techniques, we observed that one of the polymorphs had an increased tendency to undergo secondary nucleation and we showed that this could explain the differences in reactivity observed in in vitro seed amplification assay and cellular assays. Simulations and high-resolution microscopy suggest that a 100-fold difference in the apparent rate of growth can be generated by a surprisingly low number of secondary nucleation "points" (1 every 2000 monomers added by elongation). When both strains are present in the same seeded reaction, secondary nucleation displaces proportions dramatically and causes a single strain to dominate the reaction as the major end product.
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Affiliation(s)
- Derrick Lau
- EMBL Australia Node for Single Molecule Science and School of Biomedical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Yuan Tang
- Brain and Mind Centre and Faculty of Medicine and Health, School of Medical Sciences, University of Sydney, Camperdown, NSW 2050, Australia
| | - Vijaya Kenche
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Thomas Copie
- EMBL Australia Node for Single Molecule Science and School of Biomedical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Daryan Kempe
- EMBL Australia Node for Single Molecule Science and School of Biomedical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Eve Jary
- EMBL Australia Node for Single Molecule Science and School of Biomedical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Noah J Graves
- EMBL Australia Node for Single Molecule Science and School of Biomedical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Maté Biro
- EMBL Australia Node for Single Molecule Science and School of Biomedical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Colin L Masters
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Nicolas Dzamko
- Brain and Mind Centre and Faculty of Medicine and Health, School of Medical Sciences, University of Sydney, Camperdown, NSW 2050, Australia
| | - Yann Gambin
- EMBL Australia Node for Single Molecule Science and School of Biomedical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Emma Sierecki
- EMBL Australia Node for Single Molecule Science and School of Biomedical Sciences, Faculty of Medicine, The University of New South Wales, Sydney, NSW 2052, Australia
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Zampar S, Di Gregorio SE, Grimmer G, Watts JC, Ingelsson M. "Prion-like" seeding and propagation of oligomeric protein assemblies in neurodegenerative disorders. Front Neurosci 2024; 18:1436262. [PMID: 39161653 PMCID: PMC11330897 DOI: 10.3389/fnins.2024.1436262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Accepted: 07/17/2024] [Indexed: 08/21/2024] Open
Abstract
Intra- or extracellular aggregates of proteins are central pathogenic features in most neurodegenerative disorders. The accumulation of such proteins in diseased brains is believed to be the end-stage of a stepwise aggregation of misfolded monomers to insoluble cross-β fibrils via a series of differently sized soluble oligomers/protofibrils. Several studies have shown how α-synuclein, amyloid-β, tau and other amyloidogenic proteins can act as nucleating particles and thereby share properties with misfolded forms, or strains, of the prion protein. Although the roles of different protein assemblies in the respective aggregation cascades remain unclear, oligomers/protofibrils are considered key pathogenic species. Numerous observations have demonstrated their neurotoxic effects and a growing number of studies have indicated that they also possess seeding properties, enabling their propagation within cellular networks in the nervous system. The seeding behavior of oligomers differs between the proteins and is also affected by various factors, such as size, shape and epitope presentation. Here, we are providing an overview of the current state of knowledge with respect to the "prion-like" behavior of soluble oligomers for several of the amyloidogenic proteins involved in neurodegenerative diseases. In addition to providing new insight into pathogenic mechanisms, research in this field is leading to novel diagnostic and therapeutic opportunities for neurodegenerative diseases.
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Affiliation(s)
- Silvia Zampar
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - Sonja E. Di Gregorio
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - Gustavo Grimmer
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - Joel C. Watts
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Martin Ingelsson
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
- Department of Public Health/Geriatrics, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
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3
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Uckelmann M, Levina V, Taveneau C, Ng XH, Pandey V, Martinez J, Mendiratta S, Houx J, Boudes M, Venugopal H, Trépout S, Zhang Q, Flanigan S, Li M, Sierecki E, Gambin Y, Das PP, Bell O, de Marco A, Davidovich C. Dynamic PRC1-CBX8 stabilizes a porous structure of chromatin condensates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.08.539931. [PMID: 38405976 PMCID: PMC10888862 DOI: 10.1101/2023.05.08.539931] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
The compaction of chromatin is a prevalent paradigm in gene repression. Chromatin compaction is commonly thought to repress transcription by restricting chromatin accessibility. However, the spatial organisation and dynamics of chromatin compacted by gene-repressing factors are unknown. Using cryo-electron tomography, we solved the three-dimensional structure of chromatin condensed by the Polycomb Repressive Complex 1 (PRC1) in a complex with CBX8. PRC1-condensed chromatin is porous and stabilised through multivalent dynamic interactions of PRC1 with chromatin. Mechanistically, positively charged residues on the internally disordered regions (IDRs) of CBX8 mask negative charges on the DNA to stabilize the condensed state of chromatin. Within condensates, PRC1 remains dynamic while maintaining a static chromatin structure. In differentiated mouse embryonic stem cells, CBX8-bound chromatin remains accessible. These findings challenge the idea of rigidly compacted polycomb domains and instead provides a mechanistic framework for dynamic and accessible PRC1-chromatin condensates.
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Charles-Achille S, Janot JM, Cayrol B, Balme S. Influence of Seed structure on Volume distribution of α-Synuclein Oligomer at Early Stages of Aggregation using nanopipette. Chembiochem 2024; 25:e202300748. [PMID: 38240074 DOI: 10.1002/cbic.202300748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/18/2024] [Indexed: 02/04/2024]
Abstract
Understanding α-synuclein aggregation is crucial in the context of Parkinson's disease. The objective of this study was to investigate the influence of aggregation induced by preformed seeding on the volume of oligomers during the early stages, using a label-free, single-molecule characterization approach. By utilizing nanopipettes of varying sizes, the volume of the oligomers can be calculated from the amplitude of the current blockade and pipette geometry. Further investigation of the aggregates formed over time in the presence of added seeds revealed an acceleration in the formation of large aggregates and the existence of multiple distinct populations of oligomers. Additionally, we observed that spontaneously formed seeds inhibited the formation of smaller oligomers, in contrast to the effect of HNE seeds. These results suggest that the seeds play a crucial role in the formation of oligomers and their sizes during the early stages of aggregation, whereas the classical thioflavin T assay remains negative.
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Affiliation(s)
- Saly Charles-Achille
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095, Montpellier cedex 5, France
| | - Jean-Marc Janot
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095, Montpellier cedex 5, France
| | - Bastien Cayrol
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, 34000, Montpellier, France
| | - Sebastien Balme
- PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD, 34000, Montpellier, France
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Gilboa T, Swank Z, Thakur R, Gould RA, Ooi KH, Norman M, Flynn EA, Deveney BT, Chen A, Borberg E, Kuzkina A, Ndayisaba A, Khurana V, Weitz DA, Walt DR. Toward the quantification of α-synuclein aggregates with digital seed amplification assays. Proc Natl Acad Sci U S A 2024; 121:e2312031121. [PMID: 38194461 PMCID: PMC10801878 DOI: 10.1073/pnas.2312031121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 11/22/2023] [Indexed: 01/11/2024] Open
Abstract
The quantification and characterization of aggregated α-synuclein in clinical samples offer immense potential toward diagnosing, treating, and better understanding neurodegenerative synucleinopathies. Here, we developed digital seed amplification assays to detect single α-synuclein aggregates by partitioning the reaction into microcompartments. Using pre-formed α-synuclein fibrils as reaction seeds, we measured aggregate concentrations as low as 4 pg/mL. To improve our sensitivity, we captured aggregates on antibody-coated magnetic beads before running the amplification reaction. By first characterizing the pre-formed fibrils with transmission electron microscopy and size exclusion chromatography, we determined the specific aggregates targeted by each assay platform. Using brain tissue and cerebrospinal fluid samples collected from patients with Parkinson's Disease and multiple system atrophy, we demonstrated that the assay can detect endogenous pathological α-synuclein aggregates. Furthermore, as another application for these assays, we studied the inhibition of α-synuclein aggregation in the presence of small-molecule inhibitors and used a custom image analysis pipeline to quantify changes in aggregate growth and filament morphology.
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Affiliation(s)
- Tal Gilboa
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
- Harvard Medical School, Boston, MA02115
| | - Zoe Swank
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
- Harvard Medical School, Boston, MA02115
| | - Rohan Thakur
- John A. Paulson School of Engineering & Applied Sciences, Harvard University, Cambridge, MA02138
- Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Russell A. Gould
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
| | - Kean Hean Ooi
- Department of Medical Sciences, Harvard Medical School, Boston, MA02115
| | - Maia Norman
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
- Harvard Medical School, Boston, MA02115
- Physician Scientist Training Program, Massachusetts General Hospital/McLean Residency in Adult Psychiatry, Boston, MA02114
| | - Elizabeth A. Flynn
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
| | - Brendan T. Deveney
- John A. Paulson School of Engineering & Applied Sciences, Harvard University, Cambridge, MA02138
| | - Anqi Chen
- John A. Paulson School of Engineering & Applied Sciences, Harvard University, Cambridge, MA02138
| | - Ella Borberg
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
- Harvard Medical School, Boston, MA02115
| | - Anastasia Kuzkina
- Harvard Medical School, Boston, MA02115
- Department of Neurology, Brigham and Women’s Hospital, Boston, MA02115
| | - Alain Ndayisaba
- Harvard Medical School, Boston, MA02115
- Department of Neurology, Brigham and Women’s Hospital, Boston, MA02115
| | - Vikram Khurana
- Harvard Medical School, Boston, MA02115
- Department of Neurology, Brigham and Women’s Hospital, Boston, MA02115
- Harvard Stem Cell Institute, Cambridge, MA02138
- Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA02142
| | - David A. Weitz
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
- John A. Paulson School of Engineering & Applied Sciences, Harvard University, Cambridge, MA02138
- Department of Physics, Harvard University, Cambridge, MA02138
| | - David R. Walt
- Department of Pathology, Brigham and Women’s Hospital, Boston, MA02115
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115
- Harvard Medical School, Boston, MA02115
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Moderne M, Abrao-Nemeir I, Meyer N, Du J, Charles-Achille S, Janot JM, Torrent J, Lepoitevin M, Balme S. Combining iontronic, chromatography and nanopipette for Aβ42 aggregates detection and separation. Anal Chim Acta 2023; 1275:341587. [PMID: 37524475 DOI: 10.1016/j.aca.2023.341587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/13/2023] [Accepted: 07/04/2023] [Indexed: 08/02/2023]
Abstract
In this work, we aim to capture, detect and analysis at single molecule level Aβ42 aggregates. To this end, two strategies of track-etched nanopore membranes functionalization were investigated. The first one uses an aptamer and requires only three steps, whereas the second strategy uses Lecanemab antibodies and requires six steps. Out of the two presented strategies, the second one was found to be the most suitable to detect Aβ42 aggregates using a quick current-voltage readout. The resulting single nanopore was then upscale to multipore membranes to capture the Aβ42 aggregates before analysis through them through a single-molecule approach. By comparing the species present in the retentate and filtrate, we confirmed the membrane's affinity for the larger Aβ42 aggregates present in the sample. We found that chromatographic membranes combined with an ionic diode for binary on/off readout are powerful tools for detecting rare biomarkers before single molecule analysis.
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Affiliation(s)
- Mathilde Moderne
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095, Montpellier, Cedex 5, France
| | - Imad Abrao-Nemeir
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095, Montpellier, Cedex 5, France
| | - Nathan Meyer
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095, Montpellier, Cedex 5, France; INM, University of Montpellier, INSERM, Montpellier, France
| | - Jun Du
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095, Montpellier, Cedex 5, France
| | - Saly Charles-Achille
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095, Montpellier, Cedex 5, France
| | - Jean-Marc Janot
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095, Montpellier, Cedex 5, France
| | - Joan Torrent
- INM, University of Montpellier, INSERM, Montpellier, France
| | - Mathilde Lepoitevin
- Institut des Matériaux Poreux de Paris (IMAP), UMR 8004 CNRS, Ecole Normale Supérieure de Paris, Ecole Supérieure de Physique et de Chimie Industrielles de Paris, PSL Université, 75005, Paris, France
| | - Sebastien Balme
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095, Montpellier, Cedex 5, France.
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Abrao-Nemeir I, Meyer N, Nouvel A, Charles-Achille S, Janot JM, Torrent J, Balme S. Aβ42 fibril and non-fibril oligomers characterization using a nanopipette. Biophys Chem 2023; 300:107076. [PMID: 37480837 DOI: 10.1016/j.bpc.2023.107076] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/03/2023] [Accepted: 07/11/2023] [Indexed: 07/24/2023]
Abstract
The Aβ42 aggregates with different structures and morphology was investigated through a single molecule label-free technique. To this end, the quartz nanopipettes were functionalized with polyethylene glycol. The set of Aβ42- epigallocatechin-3-gallate fibrils with length (from 85 nm to 250 nm) obtained by sonication was detected. The comparison of experimental and computed value of the amplitude of relative current blockade using a geometrical model show that for fibrils longer than 80 nm, the discriminating parameter is their diameter. Then, non-fibril oligomers obtain from Aβ42(Osaka) aggregation at different time seed was investigated. The analysis of the amplitude of relative current blockade shows that detected oligomers are smaller than 30 nm regardless the aggregation time. In addition, the wide distributions of the dwell time suggests the polymorph character of the sample.
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Affiliation(s)
- Imad Abrao-Nemeir
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Nathan Meyer
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France; INM, University of Montpellier, INSERM, Montpellier, France
| | - Alexis Nouvel
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Saly Charles-Achille
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Jean-Marc Janot
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Joan Torrent
- INM, University of Montpellier, INSERM, Montpellier, France
| | - Sebastien Balme
- Institut Européen des Membranes, UMR5635 University of Montpellier ENCSM CNRS, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France.
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Meng F, Kim JY, Gopich IV, Chung HS. Single-molecule FRET and molecular diffusion analysis characterize stable oligomers of amyloid-β 42 of extremely low population. PNAS NEXUS 2023; 2:pgad253. [PMID: 37564361 PMCID: PMC10411938 DOI: 10.1093/pnasnexus/pgad253] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 07/12/2023] [Accepted: 07/21/2023] [Indexed: 08/12/2023]
Abstract
Soluble oligomers produced during protein aggregation have been thought to be toxic species causing various diseases. Characterization of these oligomers is difficult because oligomers are a heterogeneous mixture, which is not readily separable, and may appear transiently during aggregation. Single-molecule spectroscopy can provide valuable information by detecting individual oligomers, but there have been various problems in determining the size and concentration of oligomers. In this work, we develop and use a method that analyzes single-molecule fluorescence burst data of freely diffusing molecules in solution based on molecular diffusion theory and maximum likelihood method. We demonstrate that the photon count rate, diffusion time, population, and Förster resonance energy transfer (FRET) efficiency can be accurately determined from simulated data and the experimental data of a known oligomerization system, the tetramerization domain of p53. We used this method to characterize the oligomers of the 42-residue amyloid-β (Aβ42) peptide. Combining peptide incubation in a plate reader and single-molecule free-diffusion experiments allows for the detection of stable oligomers appearing at various stages of aggregation. We find that the average size of these oligomers is 70-mer and their overall population is very low, less than 1 nM, in the early and middle stages of aggregation of 1 µM Aβ42 peptide. Based on their average size and long diffusion time, we predict the oligomers have a highly elongated rod-like shape.
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Affiliation(s)
- Fanjie Meng
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Jae-Yeol Kim
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Irina V Gopich
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Hoi Sung Chung
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
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Awasthi S, Ying C, Li J, Mayer M. Simultaneous Determination of the Size and Shape of Single α-Synuclein Oligomers in Solution. ACS NANO 2023. [PMID: 37327131 DOI: 10.1021/acsnano.3c01393] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Soluble oligomers of amyloid-forming proteins are implicated as toxic species in the context of several neurodegenerative diseases. Since the size and shape of these oligomers influence their toxicity, their biophysical characterization is essential for a better understanding of the structure-toxicity relationship. Amyloid oligomers are difficult to characterize by conventional approaches due to their heterogeneity in size and shape, their dynamic aggregation process, and their low abundance. This work demonstrates that resistive pulse measurements using polymer-coated solid-state nanopores enable single-particle-level characterization of the size and shape of individual αSyn oligomers in solution within minutes. A comparison of the resulting size distribution with single-particle analysis by transmission electron microscopy and mass photometry reveals good agreement with superior resolution by nanopore-based characterization. Moreover, nanopore-based analysis has the capability to combine rapid size analysis with an approximation of the oligomer shape. Applying this shape approximation to putatively toxic oligomeric species that range in size from 18 ± 7 aggregated monomers (10S) to 29 ± 10 aggregated monomers (15S) and in concentration from picomolar to nanomolar revealed oligomer shapes that agree well with previous estimates by cryo-EM with the added advantage that nanopore-based analysis occurs rapidly, in solution, and has the potential to become a widely accessible technique.
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Affiliation(s)
- Saurabh Awasthi
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Cuifeng Ying
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
| | - Jiali Li
- University of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Michael Mayer
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, CH-1700 Fribourg, Switzerland
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