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Zhang Y, Wang Y, Liu Y, Wei G, Ding F, Sun Y. Molecular Insights into the Misfolding and Dimerization Dynamics of the Full-Length α-Synuclein from Atomistic Discrete Molecular Dynamics Simulations. ACS Chem Neurosci 2022; 13:3126-3137. [PMID: 36278939 PMCID: PMC9797213 DOI: 10.1021/acschemneuro.2c00531] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The misfolding and pathological aggregation of α-synuclein forming insoluble amyloid deposits is associated with Parkinson's disease, the second most common neurodegenerative disease in the world population. Characterizing the self-assembly mechanism of α-synuclein is critical for discovering treatments against synucleinopathies. The intrinsically disordered property, high degrees of freedom, and macroscopic timescales of conformational conversion make its characterization extremely challenging in vitro and in silico. Here, we systematically investigated the dynamics of monomer misfolding and dimerization of the full-length α-synuclein using atomistic discrete molecular dynamics simulations. Our results suggested that both α-synuclein monomers and dimers mainly adopted unstructured formations with partial helices around the N-terminus (residues 8-32) and various β-sheets spanning the residues 35-56 (N-terminal tail) and residues 61-95 (NAC region). The C-terminus mostly assumed an unstructured formation wrapping around the lateral surface and the elongation edge of the β-sheet core formed by an N-terminal tail and NAC regions. Dimerization enhanced the β-sheet formation along with a decrease in the unstructured content. The inter-peptide β-sheets were mainly formed by the N-terminal tail and NACore (residues 68-78) regions, suggesting that these two regions played critical roles in the amyloid aggregation of α-synuclein. Interactions of the C-terminus with the N-terminal tail and the NAC region were significantly suppressed in the α-synuclein dimer, indicating that the interaction of the C-terminus with the N-terminal tail and NAC regions could prevent α-synuclein aggregation. These results on the structural ensembles and early aggregation dynamics of α-synuclein will help understand the nucleation and fibrillization of α-synuclein.
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Affiliation(s)
- Yu Zhang
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Ying Wang
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Yuying Liu
- Department of Physics, Ningbo University, Ningbo 315211, China
| | - Guanghong Wei
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Feng Ding
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, USA
| | - Yunxiang Sun
- Department of Physics, Ningbo University, Ningbo 315211, China
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29634, USA
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2
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Excitation energy migration to study protein oligomerization and amyloid formation. Biophys Chem 2021; 281:106719. [PMID: 34864229 DOI: 10.1016/j.bpc.2021.106719] [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: 10/04/2021] [Revised: 11/08/2021] [Accepted: 11/10/2021] [Indexed: 11/22/2022]
Abstract
Excitation energy migration via homo-FRET (Förster resonance energy transfer) is a unique variant of traditional FRET that involves a non-radiative energy transfer between the dipoles of two or more chemical identical fluorophores in close proximity and with an overlap between its excitation and emission spectra. Such energy migrations between chemically identical fluorophores within the Förster distance having their dipoles oriented over a wide angular spread results in the depolarization of fluorescence anisotropy depending on the local density of the fluorophores. Therefore, this methodology can be employed to study protein oligomerization and amyloid fibril formation. The conceptual framework involves extracting structural information by identifying proximal and distal locations in supramolecular assemblies by monitoring the efficiency of homo-FRET between fluorophore-conjugated protein molecules within these supramolecular assemblies. This review highlights two such cases in which excitation energy migration via homo-FRET was used to characterize the formation of membrane-mediated β-sheet rich oligomers of the prion protein as well as to construct a site-specific 2D-proximity correlation map to probe inter-residue proximities within the highly organized amyloid fibrils of α-synuclein. Energy migration studies will find applications in studying a wide range of biomolecular assemblies such as lipid-protein complexes, oligomers, amyloids, and phase-separated condensates.
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Ferrie JJ, Lengyel-Zhand Z, Janssen B, Lougee MG, Giannakoulias S, Hsieh CJ, Pagar VV, Weng CC, Xu H, Graham TJA, Lee VMY, Mach RH, Petersson EJ. Identification of a nanomolar affinity α-synuclein fibril imaging probe by ultra-high throughput in silico screening. Chem Sci 2020; 11:12746-12754. [PMID: 33889379 PMCID: PMC8047729 DOI: 10.1039/d0sc02159h] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022] Open
Abstract
Small molecules that bind with high affinity and specificity to fibrils of the α-synuclein (αS) protein have the potential to serve as positron emission tomography (PET) imaging probes to aid in the diagnosis of Parkinson's disease and related synucleinopathies. To identify such molecules, we employed an ultra-high throughput in silico screening strategy using idealized pseudo-ligands termed exemplars to identify compounds for experimental binding studies. For the top hit from this screen, we used photo-crosslinking to confirm its binding site and studied the structure-activity relationship of its analogs to develop multiple molecules with nanomolar affinity for αS fibrils and moderate specificity for αS over Aβ fibrils. Lastly, we demonstrated the potential of the lead analog as an imaging probe by measuring binding to αS-enriched homogenates from mouse brain tissue using a radiolabeled analog of the identified molecule. This study demonstrates the validity of our powerful new approach to the discovery of PET probes for challenging molecular targets.
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Affiliation(s)
- John J Ferrie
- Department of Chemistry , University of Pennsylvania , 231 South 34th Street , Philadelphia , PA 19104 , USA .
| | - Zsofia Lengyel-Zhand
- Department of Radiology , Perelman School of Medicine , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , USA
| | - Bieneke Janssen
- Department of Radiology , Perelman School of Medicine , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , USA
| | - Marshall G Lougee
- Department of Chemistry , University of Pennsylvania , 231 South 34th Street , Philadelphia , PA 19104 , USA .
| | - Sam Giannakoulias
- Department of Chemistry , University of Pennsylvania , 231 South 34th Street , Philadelphia , PA 19104 , USA .
| | - Chia-Ju Hsieh
- Department of Radiology , Perelman School of Medicine , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , USA
| | - Vinayak Vishnu Pagar
- Department of Chemistry , University of Pennsylvania , 231 South 34th Street , Philadelphia , PA 19104 , USA .
| | - Chi-Chang Weng
- Department of Radiology , Perelman School of Medicine , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , USA
| | - Hong Xu
- Center for Neurodegenerative Disease Research , University of Pennsylvania , 3600 Spruce Street , Philadelphia , PA 19104 , USA
| | - Thomas J A Graham
- Department of Radiology , Perelman School of Medicine , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , USA
| | - Virginia M-Y Lee
- Center for Neurodegenerative Disease Research , University of Pennsylvania , 3600 Spruce Street , Philadelphia , PA 19104 , USA
| | - Robert H Mach
- Department of Radiology , Perelman School of Medicine , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , USA
| | - E James Petersson
- Department of Chemistry , University of Pennsylvania , 231 South 34th Street , Philadelphia , PA 19104 , USA .
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Landeck N, Strathearn KE, Ysselstein D, Buck K, Dutta S, Banerjee S, Lv Z, Hulleman JD, Hindupur J, Lin LK, Padalkar S, Stanciu LA, Lyubchenko YL, Kirik D, Rochet JC. Two C-terminal sequence variations determine differential neurotoxicity between human and mouse α-synuclein. Mol Neurodegener 2020; 15:49. [PMID: 32900375 PMCID: PMC7487555 DOI: 10.1186/s13024-020-00380-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/18/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND α-Synuclein (aSyn) aggregation is thought to play a central role in neurodegenerative disorders termed synucleinopathies, including Parkinson's disease (PD). Mouse aSyn contains a threonine residue at position 53 that mimics the human familial PD substitution A53T, yet in contrast to A53T patients, mice show no evidence of aSyn neuropathology even after aging. Here, we studied the neurotoxicity of human A53T, mouse aSyn, and various human-mouse chimeras in cellular and in vivo models, as well as their biochemical properties relevant to aSyn pathobiology. METHODS Primary midbrain cultures transduced with aSyn-encoding adenoviruses were analyzed immunocytochemically to determine relative dopaminergic neuron viability. Brain sections prepared from rats injected intranigrally with aSyn-encoding adeno-associated viruses were analyzed immunohistochemically to determine nigral dopaminergic neuron viability and striatal dopaminergic terminal density. Recombinant aSyn variants were characterized in terms of fibrillization rates by measuring thioflavin T fluorescence, fibril morphologies via electron microscopy and atomic force microscopy, and protein-lipid interactions by monitoring membrane-induced aSyn aggregation and aSyn-mediated vesicle disruption. Statistical tests consisted of ANOVA followed by Tukey's multiple comparisons post hoc test and the Kruskal-Wallis test followed by a Dunn's multiple comparisons test or a two-tailed Mann-Whitney test. RESULTS Mouse aSyn was less neurotoxic than human aSyn A53T in cell culture and in rat midbrain, and data obtained for the chimeric variants indicated that the human-to-mouse substitutions D121G and N122S were at least partially responsible for this decrease in neurotoxicity. Human aSyn A53T and a chimeric variant with the human residues D and N at positions 121 and 122 (respectively) showed a greater propensity to undergo membrane-induced aggregation and to elicit vesicle disruption. Differences in neurotoxicity among the human, mouse, and chimeric aSyn variants correlated weakly with differences in fibrillization rate or fibril morphology. CONCLUSIONS Mouse aSyn is less neurotoxic than the human A53T variant as a result of inhibitory effects of two C-terminal amino acid substitutions on membrane-induced aSyn aggregation and aSyn-mediated vesicle permeabilization. Our findings highlight the importance of membrane-induced self-assembly in aSyn neurotoxicity and suggest that inhibiting this process by targeting the C-terminal domain could slow neurodegeneration in PD and other synucleinopathy disorders.
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Affiliation(s)
- Natalie Landeck
- Brain Repair and Imaging in Neural Systems, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Katherine E. Strathearn
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN USA
- Present address: Fujifilm Irvine Scientific, Santa Ana, CA USA
| | - Daniel Ysselstein
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN USA
- Present address: Northwestern University Feinberg School of Medicine, Chicago, IL USA
| | - Kerstin Buck
- Brain Repair and Imaging in Neural Systems, Department of Experimental Medical Science, Lund University, Lund, Sweden
- Present address: AbbVie Deutschland GmbH & Co KG, Ludwigshafen, Germany
| | - Sayan Dutta
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN USA
| | - Siddhartha Banerjee
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE USA
| | - Zhengjian Lv
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE USA
- Present address: Bruker Nanosurfaces Division, Goleta, Santa Barbara, CA USA
| | - John D. Hulleman
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN USA
- Present address: Departments of Ophthalmology and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX USA
| | - Jagadish Hindupur
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN USA
- Present address: Liveon Biolabs Pvt. Ltd., Tumakuru, Karnataka India
| | - Li-Kai Lin
- School of Materials Engineering, Purdue University, West Lafayette, IN USA
| | - Sonal Padalkar
- School of Materials Engineering, Purdue University, West Lafayette, IN USA
- Present address: Department of Mechanical Engineering, Iowa State University, Ames, IA USA
| | - Lia A. Stanciu
- School of Materials Engineering, Purdue University, West Lafayette, IN USA
| | - Yuri L. Lyubchenko
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE USA
| | - Deniz Kirik
- Brain Repair and Imaging in Neural Systems, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Jean-Christophe Rochet
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN USA
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN USA
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Sorrentino ZA, Giasson BI. The emerging role of α-synuclein truncation in aggregation and disease. J Biol Chem 2020; 295:10224-10244. [PMID: 32424039 DOI: 10.1074/jbc.rev120.011743] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 05/13/2020] [Indexed: 12/21/2022] Open
Abstract
α-Synuclein (αsyn) is an abundant brain neuronal protein that can misfold and polymerize to form toxic fibrils coalescing into pathologic inclusions in neurodegenerative diseases, including Parkinson's disease, Lewy body dementia, and multiple system atrophy. These fibrils may induce further αsyn misfolding and propagation of pathologic fibrils in a prion-like process. It is unclear why αsyn initially misfolds, but a growing body of literature suggests a critical role of partial proteolytic processing resulting in various truncations of the highly charged and flexible carboxyl-terminal region. This review aims to 1) summarize recent evidence that disease-specific proteolytic truncations of αsyn occur in Parkinson's disease, Lewy body dementia, and multiple system atrophy and animal disease models; 2) provide mechanistic insights on how truncation of the amino and carboxyl regions of αsyn may modulate the propensity of αsyn to pathologically misfold; 3) compare experiments evaluating the prion-like properties of truncated forms of αsyn in various models with implications for disease progression; 4) assess uniquely toxic properties imparted to αsyn upon truncation; and 5) discuss pathways through which truncated αsyn forms and therapies targeted to interrupt them. Cumulatively, it is evident that truncation of αsyn, particularly carboxyl truncation that can be augmented by dysfunctional proteostasis, dramatically potentiates the propensity of αsyn to pathologically misfold into uniquely toxic fibrils with modulated prion-like seeding activity. Therapeutic strategies and experimental paradigms should operate under the assumption that truncation of αsyn is likely occurring in both initial and progressive disease stages, and preventing truncation may be an effective preventative strategy against pathologic inclusion formation.
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Affiliation(s)
- Zachary A Sorrentino
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida, USA.,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Benoit I Giasson
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida, USA .,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, Florida, USA.,McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
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Majumdar A, Das D, Madhu P, Avni A, Mukhopadhyay S. Excitation Energy Migration Unveils Fuzzy Interfaces within the Amyloid Architecture. Biophys J 2020; 118:2621-2626. [PMID: 32402242 DOI: 10.1016/j.bpj.2020.04.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/14/2020] [Accepted: 04/17/2020] [Indexed: 12/25/2022] Open
Abstract
Amyloid fibrils are highly ordered nanoscopic protein aggregates comprising a cross-β amyloid core and are associated with deadly human diseases. Structural studies have revealed the supramolecular architecture of a variety of disease-associated amyloids. However, the critical role of transient intermolecular interactions between the disordered polypeptide segments of protofilaments in directing the supramolecular structure and nanoscale morphology remains elusive. Here, we present a unique case to demonstrate that interchain excitation energy migration via intermolecular homo-Förster resonance energy transfer can decipher the architecture of amyloid fibrils of human α-synuclein. Site-specific homo-Förster resonance energy transfer efficiencies measured by fluorescence depolarization allowed us to construct a two-dimensional proximity correlation map that defines the supramolecular packing of α-synuclein within the fibrils. These studies captured unique heteroterminal cross talks between the fuzzy interprotofilament interfaces of the parallel-in-register amyloid spines. Our results will find applications in discerning the broader role of protein disorder and fuzziness in steering the distinct polymorphic amyloids that exhibit strain-specific disease phenotypes.
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Affiliation(s)
- Anupa Majumdar
- Centre for Protein Science, Design and Engineering, Mohali, Punjab, India; Department of Biological Sciences, Mohali, Punjab, India
| | - Debapriya Das
- Centre for Protein Science, Design and Engineering, Mohali, Punjab, India; Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Punjab, India
| | - Priyanka Madhu
- Centre for Protein Science, Design and Engineering, Mohali, Punjab, India; Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Punjab, India
| | - Anamika Avni
- Centre for Protein Science, Design and Engineering, Mohali, Punjab, India; Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Punjab, India
| | - Samrat Mukhopadhyay
- Centre for Protein Science, Design and Engineering, Mohali, Punjab, India; Department of Biological Sciences, Mohali, Punjab, India; Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Punjab, India.
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7
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Pan B, Rhoades E, Petersson EJ. Chemoenzymatic Semisynthesis of Phosphorylated α-Synuclein Enables Identification of a Bidirectional Effect on Fibril Formation. ACS Chem Biol 2020; 15:640-645. [PMID: 32065743 DOI: 10.1021/acschembio.9b01038] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Post-translational modifications (PTMs) impact the pathological aggregation of α-synuclein (αS), a hallmark of Parkinson's disease (PD). Here, we synthesize αS phosphorylated at tyrosine 39 (pY39) through a novel route using in vitro enzymatic phosphorylation of a fragment followed by ligation to form the full-length protein. We can execute this synthesis in combination with unnatural amino acid mutagenesis to include two fluorescent labels for Förster resonance energy transfer (FRET) studies. We determine the effect of pY39 on the aggregation of αS and compare our authentically phosphorylated material to the corresponding glutamate 39 "phosphomimetic." Intriguingly, we find that αS-pY39 can either accelerate or decelerate aggregation, depending on the fraction of phosphorylated protein. The αS-E39 mutant can qualitatively reproduce some, but not all, of these effects. FRET measurements and analysis of existing structures of αS help to provide an explanation for this phenomenon. Our results have important implications for the treatment of PD patients with tyrosine kinase inhibitors and highlight the importance of validating phosphomimetics through studies of authentic PTMs.
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Affiliation(s)
- Buyan Pan
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Elizabeth Rhoades
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - E. James Petersson
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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Sorrentino ZA, Xia Y, Gorion KM, Hass E, Giasson BI. Carboxy-terminal truncations of mouse α-synuclein alter aggregation and prion-like seeding. FEBS Lett 2020; 594:1271-1283. [PMID: 31912891 DOI: 10.1002/1873-3468.13728] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 12/19/2019] [Accepted: 01/02/2020] [Indexed: 12/22/2022]
Abstract
α-synuclein (αsyn) forms pathologic inclusions in several neurodegenerative diseases termed synucleinopathies. The inclusions are comprised of αsyn fibrils harboring prion-like properties. Prion-like activity of αsyn has been studied by intracerebral injection of fibrils into mice, where the presence of a species barrier requires the use of mouse αsyn. Post-translational modifications to αsyn such as carboxy (C)-terminal truncation occur in synucleinopathies, and their implications for prion-like aggregation and seeding are under investigation. Herein, C-truncated forms of αsyn found in human disease are recapitulated in mouse αsyn to study their seeding activity in vitro, in HEK293T cells, in neuronal-glial culture, and in nontransgenic mice. The results show that C-truncation of mouse αsyn accelerates aggregation of αsyn but alters prion-like seeding of inclusion formation.
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Affiliation(s)
- Zachary A Sorrentino
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, USA.,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Yuxing Xia
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, USA.,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Kimberly-Marie Gorion
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, USA.,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Ethan Hass
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, USA.,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Benoit I Giasson
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, USA.,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA.,McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, USA
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Sequence- and seed-structure-dependent polymorphic fibrils of alpha-synuclein. Biochim Biophys Acta Mol Basis Dis 2019; 1865:1410-1420. [PMID: 30790619 DOI: 10.1016/j.bbadis.2019.02.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 01/08/2019] [Accepted: 02/14/2019] [Indexed: 12/15/2022]
Abstract
Synucleinopathies comprise a diverse group of neurodegenerative diseases including Parkinson's disease (PD), dementia with Lewy bodies, and multiple system atrophy. These share a common pathological feature, the deposition of alpha-synuclein (a-syn) in neurons or oligodendroglia. A-syn is highly conserved in vertebrates, but the primary sequence of mouse a-syn differs from that of human at seven positions. However, structural differences of their aggregates remain to be fully characterized. In this study, we found that human and mouse a-syn aggregated in vitro formed morphologically distinct amyloid fibrils exhibiting twisted and straight structures, respectively. Furthermore, we identified different protease-resistant core regions, long and short, in human and mouse a-syn aggregates. Interestingly, among the seven unconserved amino acids, only A53T substitution, one of the familial PD mutations, was responsible for structural conversion to the straight-type. Finally, we checked whether the structural differences are transmissible by seeding and found that human a-syn seeded with A53T aggregates formed straight-type fibrils with short protease-resistant cores. These results suggest that a-syn aggregates form sequence-dependent polymorphic fibrils upon spontaneous aggregation but become seed structure-dependent upon seeding.
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