1
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Andersen C, Grønnemose AL, Pedersen JN, Nowak JS, Christiansen G, Nielsen J, Mulder FAA, Otzen DE, Jørgensen TJD. Lipid Peroxidation Products HNE and ONE Promote and Stabilize Alpha-Synuclein Oligomers by Chemical Modifications. Biochemistry 2021; 60:3644-3658. [PMID: 34730940 DOI: 10.1021/acs.biochem.1c00478] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The aggregation of α-synuclein (αSN) and increased oxidative stress leading to lipid peroxidation are pathological characteristics of Parkinson's disease (PD). Here, we report that aggregation of αSN in the presence of lipid peroxidation products 4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE) increases the stability and the yield of αSN oligomers (αSO). Further, we show that ONE is more efficient than HNE at inducing αSO. In addition, we demonstrate that the two αSO differ in both size and shape. ONE-αSO are smaller in size than HNE-αSO, except when they are formed at a high molar excess of aldehyde. In both monomeric and oligomeric αSN, His50 is the main target of HNE modification, and HNE-induced oligomerization is severely retarded in the mutant His50Ala αSN. In contrast, ONE-induced aggregation of His50Ala αSN occurs readily, demonstrating the different pathways for inducing αSN aggregation by HNE and ONE. Our results show different morphologies of the HNE-treated and ONE-treated αSO and different roles of His50 in their modification of αSN, but we also observe structural similarities between these αSO and the non-treated αSO, e.g., flexible C-terminus, a folded core composed of the N-terminal and NAC region. Furthermore, HNE-αSO show a similar deuterium uptake as a previously characterized oligomer formed by non-treated αSO, suggesting that the backbone conformational dynamics of their folded cores resemble one another.
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Affiliation(s)
- Camilla Andersen
- iNANO, Gustav Wieds Vej 14, Aarhus University, Aarhus C 8000, Denmark
| | - Anne Louise Grønnemose
- iNANO, Gustav Wieds Vej 14, Aarhus University, Aarhus C 8000, Denmark.,Department of Biochemistry and Molecular Biology, Campusvej 55, University of Southern Denmark, Odense M 5230, Denmark
| | - Jannik N Pedersen
- iNANO, Gustav Wieds Vej 14, Aarhus University, Aarhus C 8000, Denmark
| | - Jan S Nowak
- iNANO, Gustav Wieds Vej 14, Aarhus University, Aarhus C 8000, Denmark
| | | | - Janni Nielsen
- iNANO, Gustav Wieds Vej 14, Aarhus University, Aarhus C 8000, Denmark
| | - Frans A A Mulder
- iNANO, Gustav Wieds Vej 14, Aarhus University, Aarhus C 8000, Denmark.,Department of Chemistry, Langelandsgade 140, Aarhus University, Aarhus C 8000, Denmark
| | - Daniel Erik Otzen
- iNANO, Gustav Wieds Vej 14, Aarhus University, Aarhus C 8000, Denmark.,Department of Molecular Biology and Genetics, Aarhus University, Aarhus C 8000, Denmark
| | - Thomas J D Jørgensen
- Department of Biochemistry and Molecular Biology, Campusvej 55, University of Southern Denmark, Odense M 5230, Denmark
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2
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Mohammad-Beigi H, Aliakbari F, Sahin C, Lomax C, Tawfike A, Schafer NP, Amiri-Nowdijeh A, Eskandari H, Møller IM, Hosseini-Mazinani M, Christiansen G, Ward JL, Morshedi D, Otzen DE. Oleuropein derivatives from olive fruit extracts reduce α-synuclein fibrillation and oligomer toxicity. J Biol Chem 2019; 294:4215-4232. [PMID: 30655291 DOI: 10.1074/jbc.ra118.005723] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 01/09/2019] [Indexed: 11/06/2022] Open
Abstract
Aggregation of α-synuclein (αSN) is implicated in neuronal degeneration in Parkinson's disease and has prompted searches for natural compounds inhibiting αSN aggregation and reducing its tendency to form toxic oligomers. Oil from the olive tree (Olea europaea L.) represents the main source of fat in the Mediterranean diet and contains variable levels of phenolic compounds, many structurally related to the compound oleuropein. Here, using αSN aggregation, fibrillation, size-exclusion chromatography-multiangle light scattering (SEC-MALS)-based assays, and toxicity assays, we systematically screened the fruit extracts of 15 different olive varieties to identify compounds that can inhibit αSN aggregation and oligomer toxicity and also have antioxidant activity. Polyphenol composition differed markedly among varieties. The variety with the most effective antioxidant and aggregation activities, Koroneiki, combined strong inhibition of αSN fibril nucleation and elongation with strong disaggregation activity on preformed fibrils and prevented the formation of toxic αSN oligomers. Fractionation of the Koroneiki extract identified oleuropein aglycone, hydroxyl oleuropein aglycone, and oleuropein as key compounds responsible for the differences in inhibition across the extracts. These phenolic compounds inhibited αSN amyloidogenesis by directing αSN monomers into small αSN oligomers with lower toxicity, thereby suppressing the subsequent fibril growth phase. Our results highlight the molecular consequences of differences in the level of effective phenolic compounds in different olive varieties, insights that have implications for long-term human health.
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Affiliation(s)
- Hossein Mohammad-Beigi
- From the Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark,
| | - Farhang Aliakbari
- From the Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.,the Departments of Industrial and Environmental Biotechnology and
| | - Cagla Sahin
- From the Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.,the Department of Molecular Biology and Genetics, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
| | - Charlotte Lomax
- the Computational and Analytical Sciences Department, Rothamsted Research, West Common, Harpenden, Herts AL5 2JQ, United Kingdom
| | - Ahmed Tawfike
- the Computational and Analytical Sciences Department, Rothamsted Research, West Common, Harpenden, Herts AL5 2JQ, United Kingdom
| | - Nicholas P Schafer
- From the Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark
| | - Alireza Amiri-Nowdijeh
- Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology, P. O. Box 1417863171, Tehran, Iran
| | - Hoda Eskandari
- From the Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark
| | - Ian Max Møller
- the Department of Molecular Biology and Genetics, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark
| | - Mehdi Hosseini-Mazinani
- Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology, P. O. Box 1417863171, Tehran, Iran
| | - Gunna Christiansen
- the Department of Biomedicine-Medical Microbiology and Immunology, Aarhus University, 8000 Aarhus C, Denmark, and
| | - Jane L Ward
- the Computational and Analytical Sciences Department, Rothamsted Research, West Common, Harpenden, Herts AL5 2JQ, United Kingdom
| | - Dina Morshedi
- the Departments of Industrial and Environmental Biotechnology and
| | - Daniel E Otzen
- From the Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark, .,the Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
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3
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Kurnik M, Sahin C, Andersen CB, Lorenzen N, Giehm L, Mohammad-Beigi H, Jessen CM, Pedersen JS, Christiansen G, Petersen SV, Staal R, Krishnamurthy G, Pitts K, Reinhart PH, Mulder FAA, Mente S, Hirst WD, Otzen DE. Potent α-Synuclein Aggregation Inhibitors, Identified by High-Throughput Screening, Mainly Target the Monomeric State. Cell Chem Biol 2018; 25:1389-1402.e9. [PMID: 30197194 DOI: 10.1016/j.chembiol.2018.08.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/12/2018] [Accepted: 08/06/2018] [Indexed: 12/26/2022]
Abstract
α-Synuclein (αSN) aggregation is central to the etiology of Parkinson's disease (PD). Large-scale screening of compounds to identify aggregation inhibitors is challenged by stochastic αSN aggregation and difficulties in detecting early-stage oligomers (αSOs). We developed a high-throughput screening assay combining SDS-stimulated αSN aggregation with FRET to reproducibly detect initial stages in αSN aggregation. We screened 746,000 compounds, leading to 58 hits that markedly inhibit αSN aggregation and reduce αSOs' membrane permeabilization activity. The most effective aggregation inhibitors were derivatives of (4-hydroxynaphthalen-1-yl)sulfonamide. They interacted strongly with the N-terminal part of monomeric αSN and reduced αSO-membrane interactions, possibly by affecting electrostatic interactions. Several compounds reduced αSO toxicity toward neuronal cell lines. The inhibitors introduced chemical modifications of αSN that were, however, not a prerequisite for inhibitory activity. We also identified several phenyl-benzoxazol compounds that promoted αSN aggregation (proaggregators). These compounds may be useful tools to modulate αSN aggregation in cellula.
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Affiliation(s)
- Martin Kurnik
- iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
| | - Cagla Sahin
- iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark; Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus, Denmark
| | | | - Nikolai Lorenzen
- iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
| | - Lise Giehm
- iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
| | - Hossein Mohammad-Beigi
- iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark; Biotechnology Group, Faculty of Chemical Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran, Iran
| | - Christian Moestrup Jessen
- iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Jan Skov Pedersen
- iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | | | | | | | | | - Keith Pitts
- Genentech, 1 DNA Way, South San Francisco, CA 94080, USA
| | - Peter H Reinhart
- Forma Therapeutics, Inc.Institute for Applied Life Sciences, University of Massachusetts Amherst, 240 Thatcher Road, Amherst, MA 01003-9364, USA
| | - Frans A A Mulder
- iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark; Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Scot Mente
- Forma Therapeutics, Inc., 500 Arsenal Street, Suite 100, Watertown, MA 02472, USA
| | | | - Daniel E Otzen
- iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark; Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus, Denmark.
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4
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Mohammad-Beigi H, Morshedi D, Shojaosadati SA, Pedersen JN, Marvian AT, Aliakbari F, Christiansen G, Pedersen JS, Otzen DE. Gallic acid loaded onto polyethylenimine-coated human serum albumin nanoparticles (PEI-HSA-GA NPs) stabilizes α-synuclein in the unfolded conformation and inhibits aggregation. RSC Adv 2016. [DOI: 10.1039/c6ra08502d] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The aggregation of the 140-residue protein α-synuclein (αSN) plays a major role in the pathogenesis of different neurodegenerative disorders such as Parkinson's Disease (PD).
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Affiliation(s)
- Hossein Mohammad-Beigi
- Interdisciplinary Nanoscience Centre (iNANO)
- Aarhus University
- DK – 8000 Aarhus C
- Denmark
- Biotechnology Group
| | - Dina Morshedi
- Department of Industrial and Environmental Biotechnology
- National Institute of Genetic Engineering and Biotechnology
- Tehran
- Iran
| | | | | | - Amir Tayaranian Marvian
- Department of Biomedicine-Medical Microbiology and Immunology
- Aarhus University
- 8000 Aarhus C
- Denmark
| | - Farhang Aliakbari
- Department of Industrial and Environmental Biotechnology
- National Institute of Genetic Engineering and Biotechnology
- Tehran
- Iran
- Student Research Committee and Department of Medical Biotechnology
| | - Gunna Christiansen
- Department of Biomedicine-Medical Microbiology and Immunology
- Aarhus University
- 8000 Aarhus C
- Denmark
| | - Jan Skov Pedersen
- Interdisciplinary Nanoscience Centre (iNANO)
- Aarhus University
- DK – 8000 Aarhus C
- Denmark
- Department of Chemistry
| | - Daniel E. Otzen
- Interdisciplinary Nanoscience Centre (iNANO)
- Aarhus University
- DK – 8000 Aarhus C
- Denmark
- Department of Molecular Biology and Genetics
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5
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Mohammad-Beigi H, Shojaosadati SA, Marvian AT, Pedersen JN, Klausen LH, Christiansen G, Pedersen JS, Dong M, Morshedi D, Otzen DE. Strong interactions with polyethylenimine-coated human serum albumin nanoparticles (PEI-HSA NPs) alter α-synuclein conformation and aggregation kinetics. NANOSCALE 2015; 7:19627-19640. [PMID: 26549058 DOI: 10.1039/c5nr05663b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The interaction between nanoparticles (NPs) and the small intrinsically disordered protein α-synuclein (αSN), whose aggregation is central in the development of Parkinson's disease, is of great relevance in biomedical applications of NPs as drug carriers. Here we showed using a combination of different techniques that αSN interacts strongly with positively charged polyethylenimine-coated human serum albumin (PEI-HSA) NPs, leading to a significant alteration in the αSN secondary structure. In contrast, the weak interactions of αSN with HSA NPs allowed αSN to remain unfolded. These different levels of interactions had different effects on αSN aggregation. While the weakly interacting HSA NPs did not alter the aggregation kinetic parameters of αSN, the rate of primary nucleation increased in the presence of PEI-HSA NPs. The aggregation rate changed in a PEI-HSA NP-concentration dependent and size independent manner and led to fibrils which were covered with small aggregates. Furthermore, PEI-HSA NPs reduced the level of membrane-perturbing oligomers and reduced oligomer toxicity in cell assays, highlighting a potential role for NPs in reducing αSN pathogenicity in vivo. Collectively, our results highlight the fact that a simple modification of NPs can strongly modulate interactions with target proteins, which may have important and positive implications in NP safety.
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Affiliation(s)
- Hossein Mohammad-Beigi
- Interdisciplinary Nanoscience Centre (iNANO) and Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 14, DK - 8000 Aarhus C, Denmark. and Biotechnology Group, Faculty of Chemical Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran, Iran
| | - Seyed Abbas Shojaosadati
- Biotechnology Group, Faculty of Chemical Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran, Iran
| | | | - Jannik Nedergaard Pedersen
- Interdisciplinary Nanoscience Centre (iNANO) and Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 14, DK - 8000 Aarhus C, Denmark.
| | - Lasse Hyldgaard Klausen
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK - 8000 Aarhus C, Denmark
| | - Gunna Christiansen
- Department of Biomedicine-Medical Microbiology and Immunology, Aarhus University, 8000 Aarhus C, Denmark
| | - Jan Skov Pedersen
- Interdisciplinary Nanoscience Centre (iNANO) and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, DK - 8000 Aarhus C, Denmark
| | - Mingdong Dong
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, DK - 8000 Aarhus C, Denmark
| | - Dina Morshedi
- Department of Industrial and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology, P.O. Box: 1417863171, Tehran, Iran.
| | - Daniel E Otzen
- Interdisciplinary Nanoscience Centre (iNANO) and Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 14, DK - 8000 Aarhus C, Denmark.
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6
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Paslawski W, Andreasen M, Nielsen SB, Lorenzen N, Thomsen K, Kaspersen JD, Pedersen JS, Otzen DE. High stability and cooperative unfolding of α-synuclein oligomers. Biochemistry 2014; 53:6252-63. [PMID: 25216651 DOI: 10.1021/bi5007833] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Many neurodegenerative diseases are linked with formation of amyloid aggregates. It is increasingly accepted that not the fibrils but rather oligomeric species are responsible for degeneration of neuronal cells. Strong evidence suggests that in Parkinson's disease (PD), cytotoxic α-synuclein (αSN) oligomers are key to pathogenicity. Nevertheless, insight into the oligomers' molecular properties remains scarce. Here we show that αSN oligomers, despite a large amount of disordered structure, are remarkably stable against extreme pH, temperature, and even molar amounts of chemical denaturants, though they undergo cooperative unfolding at higher denaturant concentrations. Mutants found in familial PD lead to slightly larger oligomers whose stabilities are very similar to that of wild-type αSN. Isolated oligomers do not revert to monomers but predominantly form larger aggregates consisting of stacked oligomers, suggesting that they are off-pathway relative to the process of fibril formation. We also demonstrate that 4-(dicyanovinyl)julolidine (DCVJ) can be used as a specific probe for detection of αSN oligomers. The high stability of the αSN oligomer indicates that therapeutic strategies should aim to prevent the formation of or passivate rather than dissociate this cytotoxic species.
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Affiliation(s)
- Wojciech Paslawski
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University , Gustav Wieds Vej 14, DK - 8000 Aarhus C, Denmark
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7
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Lorenzen N, Nielsen SB, Buell AK, Kaspersen JD, Arosio P, Vad BS, Paslawski W, Christiansen G, Valnickova-Hansen Z, Andreasen M, Enghild JJ, Pedersen JS, Dobson CM, Knowles TPJ, Otzen DE. The role of stable α-synuclein oligomers in the molecular events underlying amyloid formation. J Am Chem Soc 2014; 136:3859-68. [PMID: 24527756 DOI: 10.1021/ja411577t] [Citation(s) in RCA: 186] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Studies of proteins' formation of amyloid fibrils have revealed that potentially cytotoxic oligomers frequently accumulate during fibril formation. An important question in the context of mechanistic studies of this process is whether or not oligomers are intermediates in the process of amyloid fibril formation, either as precursors of fibrils or as species involved in the fibril elongation process or instead if they are associated with an aggregation process that is distinct from that generating mature fibrils. Here we describe and characterize in detail two well-defined oligomeric species formed by the protein α-synuclein (αSN), whose aggregation is strongly implicated in the development of Parkinson's disease (PD). The two types of oligomers are both formed under conditions where amyloid fibril formation is observed but differ in molecular weight by an order of magnitude. Both possess a degree of β-sheet structure that is intermediate between that of the disordered monomer and the fully structured amyloid fibrils, and both have the capacity to permeabilize vesicles in vitro. The smaller oligomers, estimated to contain ∼30 monomers, are more numerous under the conditions used here than the larger ones, and small-angle X-ray scattering data suggest that they are ellipsoidal with a high degree of flexibility at the interface with solvent. This oligomer population is unable to elongate fibrils and indeed results in an inhibition of the kinetics of amyloid formation in a concentration-dependent manner.
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Affiliation(s)
- Nikolai Lorenzen
- Department of Molecular Biology, Center for Insoluble Protein Structures (inSPIN) and §Department of Chemistry, Interdisciplinary Nanoscience Center (iNANO), Aarhus University , Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
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8
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Andreasen M, Nielsen SB, Runager K, Christiansen G, Nielsen NC, Enghild JJ, Otzen DE. Polymorphic fibrillation of the destabilized fourth fasciclin-1 domain mutant A546T of the Transforming growth factor-β-induced protein (TGFBIp) occurs through multiple pathways with different oligomeric intermediates. J Biol Chem 2012; 287:34730-42. [PMID: 22893702 DOI: 10.1074/jbc.m112.379552] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the transforming growth factor β-induced protein (TGFBIp) are linked to the development of corneal dystrophies in which abnormal protein deposition in the cornea leads to a loss of corneal transparency and ultimately blindness. Different mutations give rise to phenotypically distinct corneal dystrophies. Most mutations are located in the fourth fasciclin-1 domain (FAS1-4). The amino acid substitution A546T in the FAS1-4 domain is linked to the development of lattice corneal dystrophy with amyloid deposits in the superficial and deep stroma, classifying it as an amyloid disease. Here we provide a detailed description of the fibrillation of the isolated FAS1-4 domain carrying the A546T substitution. The A546T substitution leads to a significant destabilization of FAS1-4 and induces a partially folded structure with increased surface exposure of hydrophobic patches. The mutation also leads to two distinct fibril morphologies. Long straight fibrils composed of pure β-sheet structure are formed at lower concentrations, whereas short and curly fibrils containing a mixture of α-helical and β-sheet structures are formed at higher concentrations. The formation of short and curly fibrils is preceded by the formation of a small number of oligomeric species with high membrane permeabilization potential and rapid fibril formation. The long straight fibrils are formed more slowly and through progressively bigger oligomers that lose their membrane permeabilization potential as fibrillation proceeds beyond the lag phase. These different fibril classes and associated biochemical differences may lead to different clinical symptoms associated with the mutation.
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Affiliation(s)
- Maria Andreasen
- Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus, Denmark
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9
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Giehm L, Svergun DI, Otzen DE, Vestergaard B. Low-resolution structure of a vesicle disrupting α-synuclein oligomer that accumulates during fibrillation. Proc Natl Acad Sci U S A 2011; 108:3246-51. [PMID: 21300904 PMCID: PMC3044375 DOI: 10.1073/pnas.1013225108] [Citation(s) in RCA: 188] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
One of the major hallmarks of Parkinson disease is aggregation of the protein α-synuclein (αSN). Aggregate cytotoxicity has been linked to an oligomeric species formed at early stages in the aggregation process. Here we follow the fibrillation process of αSN in solution over time using small angle X-ray scattering and resolve four major coexisting species in the fibrillation process, namely monomer, dimer, fibril and an oligomer. By ab initio modeling to fit the data, we obtain a low-resolution structure of a symmetrical and slender αSN fibril in solution, consisting of a repeating unit with a maximal distance of 900 Å and a diameter of ∼180 Å. The same approach shows the oligomer to be shaped like a wreath, with a central channel and with dimensions corresponding to the width of the fibril. The structure, accumulation and decay of this oligomer is consistent with an on-pathway role for the oligomer in the fibrillation process. We propose an oligomer-driven αSN fibril formation mechanism, where the fibril is built from the oligomers. The wreath-shaped structure of the oligomer highlights its potential cytotoxicity by simple membrane permeabilization. This is confirmed by the ability of the purified oligomer to disrupt liposomes. Our results provide the first structural description in solution of a potentially cytotoxic oligomer, which accumulates during the fibrillation of αSN.
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Affiliation(s)
- Lise Giehm
- Department of Medicinal Chemistry and Department of Analytical Chemistry and Pharmaceutics, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark
- Department of Life Sciences, Aalborg University, Sohngaardsholmsvej 49, 9000 Aalborg; and
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory, Hamburg Outstation, Notkestrasse 85, 22603 Hamburg, Germany
| | - Daniel E. Otzen
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark
- Department of Life Sciences, Aalborg University, Sohngaardsholmsvej 49, 9000 Aalborg; and
| | - Bente Vestergaard
- Department of Medicinal Chemistry and Department of Analytical Chemistry and Pharmaceutics, Faculty of Pharmaceutical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
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10
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Giehm L, Lorenzen N, Otzen DE. Assays for α-synuclein aggregation. Methods 2010; 53:295-305. [PMID: 21163351 DOI: 10.1016/j.ymeth.2010.12.008] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 12/08/2010] [Accepted: 12/08/2010] [Indexed: 01/06/2023] Open
Abstract
This review describes different ways to achieve and monitor reproducible aggregation of α-synuclein, a key protein in the development of Parkinson's disease. For most globular proteins, aggregation is promoted by partially denaturing conditions which compromise the native state without destabilizing the intermolecular contacts required for accumulation of regular amyloid structure. As a natively disordered protein, α-synuclein can fibrillate under physiological conditions and this process is actually stimulated by conditions that promote structure formation, such as low pH, ions, polyamines, anionic surfactants, fluorinated alcohols and agitation. Reproducibility is a critical issue since α-synuclein shows erratic fibrillation behavior on its own. Agitation in combination with glass beads significantly reduces the variability of aggregation time curves, but the most reproducible aggregation is achieved by sub-micellar concentrations of SDS, which promote the rapid formation of small clusters of α-synuclein around shared micelles. Although the fibrils produced this way have a different appearance and secondary structure, they are rich in cross-β structure and are amenable to high-throughput screening assays. Although such assays at best provide a very simplistic recapitulation of physiological conditions, they allow the investigator to focus on well-defined molecular events and may provide the opportunity to identify, e.g. small molecule inhibitors of aggregation that affect these steps. Subsequent experiments in more complex cellular and whole-organism environments can then validate whether there is any relation between these molecular interactions and the broader biological context.
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Affiliation(s)
- Lise Giehm
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology, Gustav Wieds Vej 10C, DK - 8000 Aarhus C, Denmark
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11
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Strategies to increase the reproducibility of protein fibrillization in plate reader assays. Anal Biochem 2010; 400:270-81. [PMID: 20149780 DOI: 10.1016/j.ab.2010.02.001] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2009] [Revised: 02/01/2010] [Accepted: 02/03/2010] [Indexed: 11/24/2022]
Abstract
There is great interest in developing reproducible high-throughput screens to identify small molecular inhibitors of protein fibrillization and aggregation for possible therapy against deposition diseases such as Alzheimer's and Parkinson's (PD). We have made a methodical analysis of factors increasing the reproducibility of the fibrillization of alpha-synuclein (alphaSN), a 140-amino-acid protein implicated in PD and notorious for its erratic fibrillization behavior. Salts and polyanionic polymers do not significantly improve the quality of the assay. However, an orbital agitation mode in the plate reader is a crucial first step toward reproducible alphaSN fibrillization. Higher reproducibility is achieved by the addition of glass beads, as evaluated by the percentage standard deviation of the nucleation and elongation rate constants and the end-stage fluorescence intensity of the fibril-binding dye thioflavin T (ThT). The highest reproducibility is obtained by either seeding the solution with preformed fibrils or by adding submicellar amounts of sodium dodecyl sulfate (SDS), where we obtain percentage standard deviations of 3-4% on the end ThT level. We conclude that there are multiple ways to achieve satisfactory levels of reproducibility, although the different conditions used to induce aggregation may lead to different fibrillization pathways.
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Abstract
The highly toxic A beta (25-35) is a peculiar peptide that differs from all the other commonly studied beta-amyloid peptides because of its extremely rapid aggregation properties and enhanced neurotoxicity. We investigated A beta (25-35) aggregation in H2O at pH 3.0 and at pH 7.4 by means of in-solution analyses. Adopting UV spectroscopy, Congo red spectrophotometry and thioflavin T fluorimetry, we were able to quantify, in water, the very fast assembling time necessary for A beta (25-35) to form stable insoluble aggregates and their ability to seed or not seed fibril growth. Our quantitative results, which confirm a very rapid assembly leading to stable insoluble aggregates of A beta (25-35) only when incubated at pH 7.4, might be helpful for designing novel aggregation inhibitors and to shed light on the in vivo environment in which fibril formation takes place.
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