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Chau CC, Maffeo CM, Aksimentiev A, Radford SE, Hewitt EW, Actis P. Single molecule delivery into living cells. Nat Commun 2024; 15:4403. [PMID: 38782907 PMCID: PMC11116494 DOI: 10.1038/s41467-024-48608-3] [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: 02/12/2024] [Accepted: 05/02/2024] [Indexed: 05/25/2024] Open
Abstract
Controlled manipulation of cultured cells by delivery of exogenous macromolecules is a cornerstone of experimental biology. Here we describe a platform that uses nanopipettes to deliver defined numbers of macromolecules into cultured cell lines and primary cells at single molecule resolution. In the nanoinjection platform, the nanopipette is used as both a scanning ion conductance microscope (SICM) probe and an injection probe. The SICM is used to position the nanopipette above the cell surface before the nanopipette is inserted into the cell into a defined location and to a predefined depth. We demonstrate that the nanoinjection platform enables the quantitative delivery of DNA, globular proteins, and protein fibrils into cells with single molecule resolution and that delivery results in a phenotypic change in the cell that depends on the identity of the molecules introduced. Using experiments and computational modeling, we also show that macromolecular crowding in the cell increases the signal-to-noise ratio for the detection of translocation events, thus the cell itself enhances the detection of the molecules delivered.
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Affiliation(s)
- Chalmers C Chau
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
- School of Electronic and Electrical Engineering and Pollard Institute, University of Leeds, Leeds, LS2 9JT, UK
- Bragg Centre for Materials Research, University of Leeds, Leeds, UK
| | - Christopher M Maffeo
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Aleksei Aksimentiev
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Sheena E Radford
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Eric W Hewitt
- School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.
| | - Paolo Actis
- School of Electronic and Electrical Engineering and Pollard Institute, University of Leeds, Leeds, LS2 9JT, UK.
- Bragg Centre for Materials Research, University of Leeds, Leeds, UK.
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2
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Mekonnen G, Djaja N, Yuan X, Myong S. Advanced imaging techniques for studying protein phase separation in living cells and at single-molecule level. Curr Opin Chem Biol 2023; 76:102371. [PMID: 37523989 PMCID: PMC10528199 DOI: 10.1016/j.cbpa.2023.102371] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/04/2023] [Accepted: 06/24/2023] [Indexed: 08/02/2023]
Abstract
Protein-protein and protein-RNA interactions are essential for cell function and survival. These interactions facilitate the formation of ribonucleoprotein complexes and biomolecular condensates via phase separation. Such assembly is involved in transcription, splicing, translation and stress response. When dysregulated, proteins and RNA can undergo irreversible aggregation which can be cytotoxic and pathogenic. Despite technical advances in investigating biomolecular condensates, achieving the necessary spatiotemporal resolution to deduce the parameters that govern their assembly and behavior has been challenging. Many laboratories have applied advanced microscopy methods for imaging condensates. For example, single molecule imaging methods have enabled the detection of RNA-protein interaction, protein-protein interaction, protein conformational dynamics, and diffusional motion of molecules that report on the intrinsic molecular interactions underlying liquid-liquid phase separation. This review will outline advances in both microscopy and spectroscopy techniques which allow single molecule detection and imaging, and how these techniques can be used to probe unique aspects of biomolecular condensates.
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Affiliation(s)
- Gemechu Mekonnen
- Program in Cellular Molecular Developmental Biology and Biophysics, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
| | - Nathalie Djaja
- Program in Cellular Molecular Developmental Biology and Biophysics, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
| | - Xincheng Yuan
- Program in Cellular Molecular Developmental Biology and Biophysics, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA
| | - Sua Myong
- Program in Cellular Molecular Developmental Biology and Biophysics, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA; Department of Biophysics, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA.
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3
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Dimou E, Katsinelos T, Meisl G, Tuck BJ, Keeling S, Smith AE, Hidari E, Lam JYL, Burke M, Lövestam S, Ranasinghe RT, McEwan WA, Klenerman D. Super-resolution imaging unveils the self-replication of tau aggregates upon seeding. Cell Rep 2023; 42:112725. [PMID: 37393617 PMCID: PMC7614924 DOI: 10.1016/j.celrep.2023.112725] [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: 10/31/2022] [Revised: 04/03/2023] [Accepted: 06/14/2023] [Indexed: 07/04/2023] Open
Abstract
Tau is a soluble protein interacting with tubulin to stabilize microtubules. However, under pathological conditions, it becomes hyperphosphorylated and aggregates, a process that can be induced by treating cells with exogenously added tau fibrils. Here, we employ single-molecule localization microscopy to resolve the aggregate species formed in early stages of seeded tau aggregation. We report that entry of sufficient tau assemblies into the cytosol induces the self-replication of small tau aggregates, with a doubling time of 5 h inside HEK cells and 1 day in murine primary neurons, which then grow into fibrils. Seeding occurs in the vicinity of the microtubule cytoskeleton, is accelerated by the proteasome, and results in release of small assemblies into the media. In the absence of seeding, cells still spontaneously form small aggregates at lower levels. Overall, our work provides a quantitative picture of the early stages of templated seeded tau aggregation in cells.
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Affiliation(s)
- Eleni Dimou
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK; UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Hills Road, Cambridge CB2 0AH, UK.
| | - Taxiarchis Katsinelos
- UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Hills Road, Cambridge CB2 0AH, UK; MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Georg Meisl
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Benjamin J Tuck
- UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Hills Road, Cambridge CB2 0AH, UK
| | - Sophie Keeling
- UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Hills Road, Cambridge CB2 0AH, UK
| | - Annabel E Smith
- UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Hills Road, Cambridge CB2 0AH, UK
| | - Eric Hidari
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK; UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Hills Road, Cambridge CB2 0AH, UK
| | - Jeff Y L Lam
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK; UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Hills Road, Cambridge CB2 0AH, UK
| | - Melanie Burke
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK; UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Hills Road, Cambridge CB2 0AH, UK
| | - Sofia Lövestam
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Rohan T Ranasinghe
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK; UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Hills Road, Cambridge CB2 0AH, UK
| | - William A McEwan
- UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Hills Road, Cambridge CB2 0AH, UK
| | - David Klenerman
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK; UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Hills Road, Cambridge CB2 0AH, UK.
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4
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Moore K, Sengupta U, Puangmalai N, Bhatt N, Kayed R. Polymorphic Alpha-Synuclein Oligomers: Characterization and Differential Detection with Novel Corresponding Antibodies. Mol Neurobiol 2023; 60:2691-2705. [PMID: 36707462 PMCID: PMC9883140 DOI: 10.1007/s12035-023-03211-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 01/04/2023] [Indexed: 01/29/2023]
Abstract
The pathological hallmark of many neurodegenerative diseases is the accumulation of characteristic proteinaceous aggregates. Parkinson's disease and dementia with Lewy bodies can be characterized as synucleinopathies due to the abnormal accumulation of the protein alpha-synuclein (α-Syn). Studies have shown amyloidogenic proteins such as α-Syn and tau can exist as polymorphic aggregates, a theory widely studied mostly in their fibrillar morphology. It is now well understood that an intermediate state of aggregates, oligomers, are the most toxic species. We have shown α-Syn, when modified by different physiological inducers, result in distinct oligomeric conformations of α-Syn. Polymorphic α-Syn oligomers exhibit distinct properties such as aggregate size, conformation, and differentially interact with tau. In this study, we confirm α-Syn oligomeric polymorphs furthermore using in-house novel α-Syn toxic conformation monoclonal antibodies (SynTCs). It is unclear the biological relevance of α-Syn oligomeric polymorphisms. Utilizing a combination of biochemical, biophysical, and cell-based assays, we characterize α-Syn oligomeric polymorphs. We found α-Syn oligomeric polymorphs exhibit distinct immunoreactivity and SynTCs exhibit differential selectivity and binding affinity for α-Syn species. Isothermal titration calorimetry experiments suggest distinct α-Syn:SynTC binding enthalpies in a species-specific manner. Additionally, we found SynTCs differentially reduce α-Syn oligomeric polymorph-mediated neurotoxicity and propagation in primary cortical neurons in a polymorph-specific manner. These studies demonstrate the biological significance of polymorphic α-Syn oligomers along with the importance of polymorph-specific antibodies that target toxic α-Syn aggregates. Monoclonal antibodies that can target the conformational heterogeneity of α-Syn oligomeric species and reduce their mediated toxicity have promising immunotherapeutic potential.
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Affiliation(s)
- Kenya Moore
- Mitchell Center for Neurodegenerative Disease, University of Texas Medical Branch, Galveston, TX, USA
- Department of Neurology, Neuroscience and Cell Biology, Medical Research Building Room 10.138C, University of Texas Medical Branch, 301 University Blvd, Galveston, TX, 77555-1045, USA
| | - Urmi Sengupta
- Mitchell Center for Neurodegenerative Disease, University of Texas Medical Branch, Galveston, TX, USA
- Department of Neurology, Neuroscience and Cell Biology, Medical Research Building Room 10.138C, University of Texas Medical Branch, 301 University Blvd, Galveston, TX, 77555-1045, USA
| | - Nicha Puangmalai
- Mitchell Center for Neurodegenerative Disease, University of Texas Medical Branch, Galveston, TX, USA
- Department of Neurology, Neuroscience and Cell Biology, Medical Research Building Room 10.138C, University of Texas Medical Branch, 301 University Blvd, Galveston, TX, 77555-1045, USA
| | - Nemil Bhatt
- Mitchell Center for Neurodegenerative Disease, University of Texas Medical Branch, Galveston, TX, USA
- Department of Neurology, Neuroscience and Cell Biology, Medical Research Building Room 10.138C, University of Texas Medical Branch, 301 University Blvd, Galveston, TX, 77555-1045, USA
| | - Rakez Kayed
- Mitchell Center for Neurodegenerative Disease, University of Texas Medical Branch, Galveston, TX, USA.
- Department of Neurology, Neuroscience and Cell Biology, Medical Research Building Room 10.138C, University of Texas Medical Branch, 301 University Blvd, Galveston, TX, 77555-1045, USA.
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5
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Gong J, Jin Z, Chen H, He J, Zhang Y, Yang X. Super-resolution fluorescence microscopic imaging in pathogenesis and drug treatment of neurological disease. Adv Drug Deliv Rev 2023; 196:114791. [PMID: 37004939 DOI: 10.1016/j.addr.2023.114791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/16/2023] [Accepted: 03/19/2023] [Indexed: 04/03/2023]
Abstract
Since super-resolution fluorescence microscopic technology breaks the diffraction limit that has existed for a long time in optical imaging, it can observe the process of synapses formed between nerve cells and the protein aggregation related to neurological disease. Thus, super-resolution fluorescence microscopic imaging has significantly impacted several industries, including drug development and pathogenesis research, and it is anticipated that it will significantly alter the future of life science research. Here, we focus on several typical super-resolution fluorescence microscopic technologies, introducing their benefits and drawbacks, as well as applications in several common neurological diseases, in the hope that their services will be expanded and improved in the pathogenesis and drug treatment of neurological diseases.
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6
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Estaun-Panzano J, Arotcarena ML, Bezard E. Monitoring α-synuclein aggregation. Neurobiol Dis 2023; 176:105966. [PMID: 36527982 PMCID: PMC9875312 DOI: 10.1016/j.nbd.2022.105966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Synucleinopathies, including Parkinson's disease (PD), dementia with Lewy Bodies (DLB), and multiple system atrophy (MSA), are characterized by the misfolding and subsequent aggregation of alpha-synuclein (α-syn) that accumulates in cytoplasmic inclusions bodies in the cells of affected brain regions. Since the seminal report of likely-aggregated α-syn presence within the Lewy bodies by Spillantini et al. in 1997, the keyword "synuclein aggregation" has appeared in over 6000 papers (Source: PubMed October 2022). Studying, observing, describing, and quantifying α-syn aggregation is therefore of paramount importance, whether it happens in tubo, in vitro, in post-mortem samples, or in vivo. The past few years have witnessed tremendous progress in understanding aggregation mechanisms and identifying various polymorphs. In this context of growing complexity, it is of utmost importance to understand what tools we possess, what exact information they provide, and in what context they may be applied. Nonetheless, it is also crucial to rationalize the relevance of the information and the limitations of these methods for gauging the final result. In this review, we present the main techniques that have shaped the current views about α-syn structure and dynamics, with particular emphasis on the recent breakthroughs that may change our understanding of synucleinopathies.
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Affiliation(s)
| | | | - Erwan Bezard
- Univ. Bordeaux, CNRS, IMN, UMR 5293, F-33000 Bordeaux, France; Motac Neuroscience Ltd, Manchester, United Kingdom.
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7
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Dissecting aggregation and seeding dynamics of α-Syn polymorphs using the phasor approach to FLIM. Commun Biol 2022; 5:1345. [PMID: 36477485 PMCID: PMC9729209 DOI: 10.1038/s42003-022-04289-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
Synucleinopathies are a heterogenous group of neurodegenerative diseases characterized by the progressive accumulation of pathological α-synuclein (α-Syn). The importance of structural polymorphism of α-Syn assemblies for distinct synucleinopathies and their progression is increasingly recognized. However, the underlying mechanisms are poorly understood. Here we use fluorescence lifetime imaging microscopy (FLIM) to investigate seeded aggregation of α-Syn in a biosensor cell line. We show that conformationally distinct α-Syn polymorphs exhibit characteristic fluorescence lifetimes. FLIM further revealed that α-Syn polymorphs were differentially processed by cellular clearance pathways, yielding fibrillar species with increased seeding capacity. Thus, FLIM is not only a powerful tool to distinguish different amyloid structures, but also to monitor the dynamic process of amyloid remodeling by the cellular environment. Our data suggest that the accumulation of highly seeding competent degradation products for particular polymorphs may account for accelerated disease progression in some patients.
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8
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Danial JSH, Lam JYL, Wu Y, Woolley M, Dimou E, Cheetham MR, Emin D, Klenerman D. Constructing a cost-efficient, high-throughput and high-quality single-molecule localization microscope for super-resolution imaging. Nat Protoc 2022; 17:2570-2619. [PMID: 36002768 DOI: 10.1038/s41596-022-00730-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 05/24/2022] [Indexed: 11/09/2022]
Abstract
Single-molecule localization microscopy (SMLM) leverages the power of modern optics to unleash ultra-precise structural nanoscopy of complex biological machines in their native environments as well as ultra-sensitive and high-throughput medical diagnostics with the sensitivity of a single molecule. To achieve this remarkable speed and resolution, SMLM setups are either built by research laboratories with strong expertise in optical engineering or commercially sold at a hefty price tag. The inaccessibility of SMLM to life scientists for technical or financial reasons is detrimental to the progress of biological and biomedical discoveries reliant on super-resolution imaging. In this work, we present the NanoPro, an economic, high-throughput, high-quality and easy-to-assemble SMLM for super-resolution imaging. We show that our instrument performs similarly to the most expensive, best-in-class commercial microscopes and rivals existing open-source microscopes at a lower price and construction complexity. To facilitate its wide adoption, we compiled a step-by-step protocol, accompanied by extensive illustrations, to aid inexperienced researchers in constructing the NanoPro as well as assessing its performance by imaging ground-truth samples as small as 20 nm. The detailed visual instructions make it possible for students with little expertise in microscopy engineering to construct, validate and use the NanoPro in <1 week, provided that all components are available.
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Affiliation(s)
- John S H Danial
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK.
- UK Dementia Research Institute, University of Cambridge, Cambridge, UK.
| | - Jeff Y L Lam
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- UK Dementia Research Institute, University of Cambridge, Cambridge, UK
| | - Yunzhao Wu
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- UK Dementia Research Institute, University of Cambridge, Cambridge, UK
| | - Matthew Woolley
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Eleni Dimou
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- UK Dementia Research Institute, University of Cambridge, Cambridge, UK
| | - Matthew R Cheetham
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- UK Dementia Research Institute, University of Cambridge, Cambridge, UK
| | - Derya Emin
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
- UK Dementia Research Institute, University of Cambridge, Cambridge, UK
| | - David Klenerman
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK.
- UK Dementia Research Institute, University of Cambridge, Cambridge, UK.
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Direct observation of heterogeneous formation of amyloid spherulites in real-time by super-resolution microscopy. Commun Biol 2022; 5:850. [PMID: 35987792 PMCID: PMC9392779 DOI: 10.1038/s42003-022-03810-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 08/05/2022] [Indexed: 12/14/2022] Open
Abstract
Protein misfolding in the form of fibrils or spherulites is involved in a spectrum of pathological abnormalities. Our current understanding of protein aggregation mechanisms has primarily relied on the use of spectrometric methods to determine the average growth rates and diffraction-limited microscopes with low temporal resolution to observe the large-scale morphologies of intermediates. We developed a REal-time kinetics via binding and Photobleaching LOcalization Microscopy (REPLOM) super-resolution method to directly observe and quantify the existence and abundance of diverse aggregate morphologies of human insulin, below the diffraction limit and extract their heterogeneous growth kinetics. Our results revealed that even the growth of microscopically identical aggregates, e.g., amyloid spherulites, may follow distinct pathways. Specifically, spherulites do not exclusively grow isotropically but, surprisingly, may also grow anisotropically, following similar pathways as reported for minerals and polymers. Combining our technique with machine learning approaches, we associated growth rates to specific morphological transitions and provided energy barriers and the energy landscape at the level of single aggregate morphology. Our unifying framework for the detection and analysis of spherulite growth can be extended to other self-assembled systems characterized by a high degree of heterogeneity, disentangling the broad spectrum of diverse morphologies at the single-molecule level. Real-time super-resolution microscopy analysis reveals the growth kinetics, morphology, and abundance of human insulin amyloid spherulites with different growth pathways.
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Meisl G, Xu CK, Taylor JD, Michaels TCT, Levin A, Otzen D, Klenerman D, Matthews S, Linse S, Andreasen M, Knowles TPJ. Uncovering the universality of self-replication in protein aggregation and its link to disease. SCIENCE ADVANCES 2022; 8:eabn6831. [PMID: 35960802 PMCID: PMC9374340 DOI: 10.1126/sciadv.abn6831] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Fibrillar protein aggregates are a hallmark of a range of human disorders, from prion diseases to dementias, but are also encountered in several functional contexts. Yet, the fundamental links between protein assembly mechanisms and their functional or pathological roles have remained elusive. Here, we analyze the aggregation kinetics of a large set of proteins that self-assemble by a nucleated-growth mechanism, from those associated with disease, over those whose aggregates fulfill functional roles in biology, to those that aggregate only under artificial conditions. We find that, essentially, all such systems, regardless of their biological role, are capable of self-replication. However, for aggregates that have evolved to fulfill a structural role, the rate of self-replication is too low to be significant on the biologically relevant time scale. By contrast, all disease-related proteins are able to self-replicate quickly compared to the time scale of the associated disease. Our findings establish the ubiquity of self-replication and point to its potential importance across aggregation-related disorders.
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Affiliation(s)
- Georg Meisl
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Catherine K. Xu
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Jonathan D. Taylor
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Thomas C. T. Michaels
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Aviad Levin
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Daniel Otzen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, Aarhus DK-8000, Denmark
| | - David Klenerman
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
- U.K. Dementia Research Institute, University of Cambridge, Cambridge CB2 0XY, UK
| | - Steve Matthews
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Sara Linse
- Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
- Corresponding author. (S.L.); (M.A.); (T.P.J.K.)
| | - Maria Andreasen
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Aarhus DK-8000, Denmark
- Corresponding author. (S.L.); (M.A.); (T.P.J.K.)
| | - Tuomas P. J. Knowles
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
- Cavendish Laboratory, University of Cambridge, 19 JJ Thomson Avenue, Cambridge CB3 0HE, UK
- Corresponding author. (S.L.); (M.A.); (T.P.J.K.)
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11
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Correia da Silva D, Valentão P, Andrade PB, Pereira DM. A Pipeline for Natural Small Molecule Inhibitors of Endoplasmic Reticulum Stress. Front Pharmacol 2022; 13:956154. [PMID: 35935873 PMCID: PMC9354955 DOI: 10.3389/fphar.2022.956154] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 06/21/2022] [Indexed: 01/22/2024] Open
Abstract
The homeostasis of eukaryotic cells is inseverable of that of the endoplasmic reticulum (ER). The main function of this organelle is the synthesis and folding of a significant portion of cellular proteins, while it is also the major calcium reservoir of the cell. Upon unresolved ER stress, a set of stress response signaling pathways that are collectively labeled as the unfolded protein response (UPR) is activated. Prolonged or intense activation of this molecular machinery may be deleterious. It is known that compromised ER homeostasis, and consequent UPR activation, characterizes the pathogenesis of neurodegenerative diseases. In an effort to discover new small molecules capable of countering ER stress, we subjected a panel of over 100 natural molecules to a battery of assays designed to evaluate several hallmarks of ER stress. The protective potential of these compounds against ER stress was evaluated at the levels of calcium homeostasis, key gene and protein expression, and levels of protein aggregation in fibroblasts. The most promising compounds were subsequently tested in neuronal cells. This framework resulted in the identification of several bioactive molecules capable of countering ER stress and deleterious events associated to it. Delphinidin stands out as the most promising candidate against neurodegeneration. This compound significantly inhibited the expression of UPR biomarkers, and displayed a strong potential to inhibit protein aggregation in the two aforementioned cell models. Our results indicate that natural products may be a valuable resource in the development of an effective therapeutic strategy against ER stress-related diseases.
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Affiliation(s)
| | | | | | - David M. Pereira
- REQUIMTE/LAQV, Laboratório de Farmacognosia, Departamento de Química, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
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12
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Meisl G, Knowles TPJ, Klenerman D. Mechanistic Models of Protein Aggregation Across Length-Scales and Time-Scales: From the Test Tube to Neurodegenerative Disease. Front Neurosci 2022; 16:909861. [PMID: 35844223 PMCID: PMC9281552 DOI: 10.3389/fnins.2022.909861] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/31/2022] [Indexed: 11/29/2022] Open
Abstract
Through advances in the past decades, the central role of aberrant protein aggregation has been established in many neurodegenerative diseases. Crucially, however, the molecular mechanisms that underlie aggregate proliferation in the brains of affected individuals are still only poorly understood. Under controlled in vitro conditions, significant progress has been made in elucidating the molecular mechanisms that take place during the assembly of purified protein molecules, through advances in both experimental methods and the theories used to analyse the resulting data. The determination of the aggregation mechanism for a variety of proteins revealed the importance of intermediate oligomeric species and of the interactions with promotors and inhibitors. Such mechanistic insights, if they can be achieved in a disease-relevant system, provide invaluable information to guide the design of potential cures to these devastating disorders. However, as experimental systems approach the situation present in real disease, their complexity increases substantially. Timescales increase from hours an aggregation reaction takes in vitro, to decades over which the process takes place in disease, and length-scales increase to the dimension of a human brain. Thus, molecular level mechanistic studies, like those that successfully determined mechanisms in vitro, have only been applied in a handful of living systems to date. If their application can be extended to further systems, including patient data, they promise powerful new insights. Here we present a review of the existing strategies to gain mechanistic insights into the molecular steps driving protein aggregation and discuss the obstacles and potential paths to achieving their application in disease. First, we review the experimental approaches and analysis techniques that are used to establish the aggregation mechanisms in vitro and the insights that have been gained from them. We then discuss how these approaches must be modified and adapted to be applicable in vivo and review the existing works that have successfully applied mechanistic analysis of protein aggregation in living systems. Finally, we present a broad mechanistic classification of in vivo systems and discuss what will be required to further our understanding of aggregate formation in living systems.
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Affiliation(s)
- Georg Meisl
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Tuomas P. J. Knowles
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, United Kingdom
| | - David Klenerman
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- UK Dementia Research Institute, University of Cambridge, Cambridge, United Kingdom
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13
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Sahoo S, Padhy AA, Kumari V, Mishra P. Role of Ubiquitin-Proteasome and Autophagy-Lysosome Pathways in α-Synuclein Aggregate Clearance. Mol Neurobiol 2022; 59:5379-5407. [PMID: 35699874 DOI: 10.1007/s12035-022-02897-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 05/21/2022] [Indexed: 11/26/2022]
Abstract
Synuclein aggregation in neuronal cells is the primary underlying cause of synucleinopathies. Changes in gene expression patterns, structural modifications, and altered interactions with other cellular proteins often trigger aggregation of α-synuclein, which accumulates as oligomers or fibrils in Lewy bodies. Although fibrillar forms of α-synuclein are primarily considered pathological, recent studies have revealed that even the intermediate states of aggregates are neurotoxic, complicating the development of therapeutic interventions. Autophagy and ubiquitin-proteasome pathways play a significant role in maintaining the soluble levels of α-synuclein inside cells; however, the heterogeneous nature of the aggregates presents a significant bottleneck to its degradation by these cellular pathways. With studies focused on identifying the proteins that modulate synuclein aggregation and clearance, detailed mechanistic insights are emerging about the individual and synergistic effects of these degradation pathways in regulating soluble α-synuclein levels. In this article, we discuss the impact of α-synuclein aggregation on autophagy-lysosome and ubiquitin-proteasome pathways and the therapeutic strategies that target various aspects of synuclein aggregation or degradation via these pathways. Additionally, we also highlight the natural and synthetic compounds that have shown promise in alleviating the cellular damage caused due to synuclein aggregation.
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Affiliation(s)
- Subhashree Sahoo
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Amrita Arpita Padhy
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Varsha Kumari
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Parul Mishra
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India.
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14
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Awa S, Suzuki G, Masuda-Suzukake M, Nonaka T, Saito M, Hasegawa M. Phosphorylation of endogenous α-synuclein induced by extracellular seeds initiates at the pre-synaptic region and spreads to the cell body. Sci Rep 2022; 12:1163. [PMID: 35064139 PMCID: PMC8782830 DOI: 10.1038/s41598-022-04780-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 12/30/2021] [Indexed: 11/16/2022] Open
Abstract
Accumulation of phosphorylated α-synuclein aggregates has been implicated in several diseases, such as Parkinson's disease (PD) and dementia with Lewy bodies (DLB), and is thought to spread in a prion-like manner. Elucidating the mechanisms of prion-like transmission of α-synuclein is important for the development of therapies for these diseases, but little is known about the details. Here, we injected α-synuclein fibrils into the brains of wild-type mice and examined the early phase of the induction of phosphorylated α-synuclein accumulation. We found that phosphorylated α-synuclein appeared within a few days after the intracerebral injection. It was observed initially in presynaptic regions and subsequently extended its localization to axons and cell bodies. These results suggest that extracellular α-synuclein fibrils are taken up into the presynaptic region and seed-dependently convert the endogenous normal α-synuclein that is abundant there to an abnormal phosphorylated form, which is then transported through the axon to the cell body.
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Affiliation(s)
- Shiori Awa
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.,Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan.,Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Genjiro Suzuki
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.
| | - Masami Masuda-Suzukake
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takashi Nonaka
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Minoru Saito
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan.,Department of Correlative Study in Physics and Chemistry, Graduate School of Integrated Basic Sciences, Nihon University, Tokyo, Japan
| | - Masato Hasegawa
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.
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15
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Kaur A, Adair LD, Ball SR, New EJ, Sunde M. A Fluorescent Sensor for Quantitative Super‐Resolution Imaging of Amyloid Fibril Assembly**. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202112832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Amandeep Kaur
- School of Medical Sciences Faculty of Medicine and Health The University of Sydney Sydney NSW 2006 Australia
- The University of Sydney Nano Institute The University of Sydney Sydney NSW 2006 Australia
| | - Liam D. Adair
- School of Chemistry The University of Sydney Sydney NSW 2006 Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science The University of Sydney Sydney NSW 2006 Australia
| | - Sarah R. Ball
- School of Medical Sciences Faculty of Medicine and Health The University of Sydney Sydney NSW 2006 Australia
| | - Elizabeth J. New
- The University of Sydney Nano Institute The University of Sydney Sydney NSW 2006 Australia
- School of Chemistry The University of Sydney Sydney NSW 2006 Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science The University of Sydney Sydney NSW 2006 Australia
| | - Margaret Sunde
- School of Medical Sciences Faculty of Medicine and Health The University of Sydney Sydney NSW 2006 Australia
- The University of Sydney Nano Institute The University of Sydney Sydney NSW 2006 Australia
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16
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Kaur A, Adair LD, Ball SR, New EJ, Sunde M. A Fluorescent Sensor for Quantitative Super-resolution Imaging of Amyloid Fibril Assembly. Angew Chem Int Ed Engl 2021; 61:e202112832. [PMID: 34935241 DOI: 10.1002/anie.202112832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Indexed: 11/07/2022]
Abstract
Many soluble proteins can self-assemble into macromolecular structures called amyloids, a subset of which are implicated in a range of neurodegenerative disorders. The nanoscale size and structural heterogeneity of prefibrillar and early aggregates, as well as mature amyloid fibrils, pose significant challenges for the quantification of amyloid species, identification of their cellular interaction partners and for elucidation of the molecular basis for cytotoxicity. We report a fluorescent amyloid sensor AmyBlink-1 and its application in super-resolution imaging of amyloid structures. AmyBlink-1 exhibits a 5-fold increase in ratio of the green (thioflavin T) to red (Alexa Fluor 647) emission intensities upon interaction with amyloid fibrils. Using AmyBlink-1 , we performed nanoscale imaging of four different types of amyloid fibrils, achieving a resolution of ~30 nm. AmyBlink-1 enables nanoscale visualization and subsequent quantification of morphological features, such as the length and skew of individual amyloid aggregates formed at different times along the amyloid assembly pathway.
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Affiliation(s)
- Amandeep Kaur
- University of Sydney, School.of Medical Sciences, University of Sydney, 2006, Sydney, AUSTRALIA
| | - Liam D Adair
- The University of Sydney, School of Chemistry, AUSTRALIA
| | - Sarah R Ball
- The University of Sydney, School of Medical Sciences, AUSTRALIA
| | | | - Margaret Sunde
- The University of Sydney, School of Medical Sciences, AUSTRALIA
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17
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Guzzo A, Delarue P, Rojas A, Nicolaï A, Maisuradze GG, Senet P. Missense Mutations Modify the Conformational Ensemble of the α-Synuclein Monomer Which Exhibits a Two-Phase Characteristic. Front Mol Biosci 2021; 8:786123. [PMID: 34912851 PMCID: PMC8667727 DOI: 10.3389/fmolb.2021.786123] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 10/25/2021] [Indexed: 12/15/2022] Open
Abstract
α-Synuclein is an intrinsically disordered protein occurring in different conformations and prone to aggregate in β-sheet structures, which are the hallmark of the Parkinson disease. Missense mutations are associated with familial forms of this neuropathy. How these single amino-acid substitutions modify the conformations of wild-type α-synuclein is unclear. Here, using coarse-grained molecular dynamics simulations, we sampled the conformational space of the wild type and mutants (A30P, A53P, and E46K) of α-synuclein monomers for an effective time scale of 29.7 ms. To characterize the structures, we developed an algorithm, CUTABI (CUrvature and Torsion based of Alpha-helix and Beta-sheet Identification), to identify residues in the α-helix and β-sheet from Cα-coordinates. CUTABI was built from the results of the analysis of 14,652 selected protein structures using the Dictionary of Secondary Structure of Proteins (DSSP) algorithm. DSSP results are reproduced with 93% of success for 10 times lower computational cost. A two-dimensional probability density map of α-synuclein as a function of the number of residues in the α-helix and β-sheet is computed for wild-type and mutated proteins from molecular dynamics trajectories. The density of conformational states reveals a two-phase characteristic with a homogeneous phase (state B, β-sheets) and a heterogeneous phase (state HB, mixture of α-helices and β-sheets). The B state represents 40% of the conformations for the wild-type, A30P, and E46K and only 25% for A53T. The density of conformational states of the B state for A53T and A30P mutants differs from the wild-type one. In addition, the mutant A53T has a larger propensity to form helices than the others. These findings indicate that the equilibrium between the different conformations of the α-synuclein monomer is modified by the missense mutations in a subtle way. The α-helix and β-sheet contents are promising order parameters for intrinsically disordered proteins, whereas other structural properties such as average gyration radius, Rg, or probability distribution of Rg cannot discriminate significantly the conformational ensembles of the wild type and mutants. When separated in states B and HB, the distributions of Rg are more significantly different, indicating that global structural parameters alone are insufficient to characterize the conformational ensembles of the α-synuclein monomer.
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Affiliation(s)
- Adrien Guzzo
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université de Bourgogne Franche-Comté, Dijon, France
| | - Patrice Delarue
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université de Bourgogne Franche-Comté, Dijon, France
| | - Ana Rojas
- Schrödinger, Inc., New York, NY, United States
| | - Adrien Nicolaï
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université de Bourgogne Franche-Comté, Dijon, France
| | - Gia G Maisuradze
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, United States
| | - Patrick Senet
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université de Bourgogne Franche-Comté, Dijon, France.,Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, United States
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18
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Sawner AS, Ray S, Yadav P, Mukherjee S, Panigrahi R, Poudyal M, Patel K, Ghosh D, Kummerant E, Kumar A, Riek R, Maji SK. Modulating α-Synuclein Liquid-Liquid Phase Separation. Biochemistry 2021; 60:3676-3696. [PMID: 34431665 DOI: 10.1021/acs.biochem.1c00434] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Liquid-liquid phase separation (LLPS) is a crucial phenomenon for the formation of functional membraneless organelles. However, LLPS is also responsible for protein aggregation in various neurodegenerative diseases such as amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease (PD). Recently, several reports, including ours, have shown that α-synuclein (α-Syn) undergoes LLPS and a subsequent liquid-to-solid phase transition, which leads to amyloid fibril formation. However, how the environmental (and experimental) parameters modulate the α-Syn LLPS remains elusive. Here, we show that in vitro α-Syn LLPS is strongly dependent on the presence of salts, which allows charge neutralization at both terminal segments of protein and therefore promotes hydrophobic interactions supportive for LLPS. Using various purification methods and experimental conditions, we showed, depending upon conditions, α-Syn undergoes either spontaneous (instantaneous) or delayed LLPS. Furthermore, we delineate that the kinetics of liquid droplet formation (i.e., the critical concentration and critical time) is relative and can be modulated by the salt/counterion concentration, pH, presence of surface, PD-associated multivalent cations, and N-terminal acetylation, which are all known to regulate α-Syn aggregation in vitro. Together, our observations suggest that α-Syn LLPS and subsequent liquid-to-solid phase transition could be pathological, which can be triggered only under disease-associated conditions (high critical concentration and/or conditions promoting α-Syn self-assembly). This study will significantly improve our understanding of the molecular mechanisms of α-Syn LLPS and the liquid-to-solid transition.
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Affiliation(s)
- Ajay Singh Sawner
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Soumik Ray
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Preeti Yadav
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Semanti Mukherjee
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Rajlaxmi Panigrahi
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Manisha Poudyal
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Komal Patel
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Dhiman Ghosh
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Eric Kummerant
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Ashutosh Kumar
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
| | - Roland Riek
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Samir K Maji
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India
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19
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Unzipping the Secrets of Amyloid Disassembly by the Human Disaggregase. Cells 2021; 10:cells10102745. [PMID: 34685723 PMCID: PMC8534776 DOI: 10.3390/cells10102745] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/08/2021] [Accepted: 10/08/2021] [Indexed: 01/08/2023] Open
Abstract
Neurodegenerative diseases (NDs) are increasingly positioned as leading causes of global deaths. The accelerated aging of the population and its strong relationship with neurodegeneration forecast these pathologies as a huge global health problem in the upcoming years. In this scenario, there is an urgent need for understanding the basic molecular mechanisms associated with such diseases. A major molecular hallmark of most NDs is the accumulation of insoluble and toxic protein aggregates, known as amyloids, in extracellular or intracellular deposits. Here, we review the current knowledge on how molecular chaperones, and more specifically a ternary protein complex referred to as the human disaggregase, deals with amyloids. This machinery, composed of the constitutive Hsp70 (Hsc70), the class B J-protein DnaJB1 and the nucleotide exchange factor Apg2 (Hsp110), disassembles amyloids of α-synuclein implicated in Parkinson’s disease as well as of other disease-associated proteins such as tau and huntingtin. We highlight recent studies that have led to the dissection of the mechanism used by this chaperone system to perform its disaggregase activity. We also discuss whether this chaperone-mediated disassembly mechanism could be used to solubilize other amyloidogenic substrates. Finally, we evaluate the implications of the chaperone system in amyloid clearance and associated toxicity, which could be critical for the development of new therapies.
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20
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Klenerman D, Sanchez SE, Whiten DR, Meisl G, Ruggeri FS, Hidari E. Alpha synuclein only forms fibrils in vitro when larger than its critical size of 70 monomers. Chembiochem 2021; 22:2867-2871. [PMID: 34383993 PMCID: PMC8518629 DOI: 10.1002/cbic.202100285] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/10/2021] [Indexed: 12/03/2022]
Abstract
The aggregation of α‐synuclein into small soluble aggregates and then fibrils is important in the development and spreading of aggregates through the brain in Parkinson's disease. Fibrillar aggregates can grow by monomer addition and then break into fragments that could spread into neighboring cells. The rate constants for fibril elongation and fragmentation have been measured but it is not known how large an aggregate needs to be before fibril formation is thermodynamically favorable. This critical size is an important parameter controlling at what stage in an aggregation reaction fibrils can form and replicate. We determined this value to be approximately 70 monomers using super‐resolution and atomic force microscopy imaging of individual α‐synuclein aggregates formed in solution over long time periods. This represents the minimum size for a stable α‐synuclein fibril and we hypothesis the formation of aggregates of this size in a cell represents a tipping point at which rapid replication occurs.
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Affiliation(s)
- David Klenerman
- University of Cambridge, Department of Chemistry, Lensfield Road, CB2 1EW, Cambridge, UNITED KINGDOM
| | | | - Daniel R Whiten
- Kolling Institute of Medical Research, Kolling Institute, AUSTRALIA
| | - Georg Meisl
- University of Cambridge, Chemistry, UNITED KINGDOM
| | - Francesco Simone Ruggeri
- Wageningen UR PRI: Wageningen University and Research Wageningen Plant Research, organic and physical chemistry Laboratories, NETHERLANDS
| | - Eric Hidari
- University of Cambridge, Chemistry, UNITED KINGDOM
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