1
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Tsekrekou M, Giannakou M, Papanikolopoulou K, Skretas G. Protein aggregation and therapeutic strategies in SOD1- and TDP-43- linked ALS. Front Mol Biosci 2024; 11:1383453. [PMID: 38855322 PMCID: PMC11157337 DOI: 10.3389/fmolb.2024.1383453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 05/02/2024] [Indexed: 06/11/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with severe socio-economic impact. A hallmark of ALS pathology is the presence of aberrant cytoplasmic inclusions composed of misfolded and aggregated proteins, including both wild-type and mutant forms. This review highlights the critical role of misfolded protein species in ALS pathogenesis, particularly focusing on Cu/Zn superoxide dismutase (SOD1) and TAR DNA-binding protein 43 (TDP-43), and emphasizes the urgent need for innovative therapeutic strategies targeting these misfolded proteins directly. Despite significant advancements in understanding ALS mechanisms, the disease remains incurable, with current treatments offering limited clinical benefits. Through a comprehensive analysis, the review focuses on the direct modulation of the misfolded proteins and presents recent discoveries in small molecules and peptides that inhibit SOD1 and TDP-43 aggregation, underscoring their potential as effective treatments to modify disease progression and improve clinical outcomes.
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Affiliation(s)
- Maria Tsekrekou
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece
| | - Maria Giannakou
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Katerina Papanikolopoulou
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Centre “Alexander Fleming”, Vari, Greece
- ResQ Biotech, Patras Science Park, Rio, Greece
| | - Georgios Skretas
- Institute of Chemical Biology, National Hellenic Research Foundation, Athens, Greece
- ResQ Biotech, Patras Science Park, Rio, Greece
- Institute for Bio-innovation, Biomedical Sciences Research Centre “Alexander Fleming”, Vari, Greece
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2
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Tammara V, Das A. Governing dynamics and preferential binding of the AXH domain influence the aggregation pathway of Ataxin-1. Proteins 2023; 91:380-394. [PMID: 36208132 DOI: 10.1002/prot.26436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 08/30/2022] [Accepted: 09/30/2022] [Indexed: 11/05/2022]
Abstract
The present state of understanding the mechanism of Spinocerebellar Ataxia-1, a fatal neurodegenerative disease linked to the protein Ataxin-1 (ATXN1), is baffled by a set of self-contradictory, and hence, inconclusive observations. This fallacy poses a bottleneck to the effective designing of curable drugs as the field is currently missing the specific druggable site. To understand the fundamentals of pathogenesis, we tried to decipher the intricacies of the extremely complicated landscape by targeting the relevant species that supposedly dictate the structure-function paradigm. The atomic-level description and characterization of the dynamism of the systems reveal the existence of structural polymorphism in all the leading stakeholders of the overall system. The very existence of conformational heterogeneity in every species creates numerous possible combinations of favorable interactions because of the variability in segmental cross-talks and hence claims its role in the choice of routes between functional activity and dysfunctional disease-causing aggregation. Despite this emergent configurational diversity, there is a common mode of operative intermolecular forces that dictates the extent of stability of all the multimeric complexes due to the localized population of a specific type of residue. The present research proposes a dynamic switch mechanism between aggregability and functional activity, based on the logical interpretation of the estimated variables, which is practically dictated by the effective concentration of the interacting species involved in the cell.
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Affiliation(s)
- Vaishnavi Tammara
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune, Maharashtra, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Atanu Das
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune, Maharashtra, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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3
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Nordström U, Lang L, Ekhtiari Bidhendi E, Zetterström P, Oliveberg M, Danielsson J, Andersen PM, Marklund SL. Mutant SOD1 aggregates formed in vitro and in cultured cells are polymorphic and differ from those arising in the CNS. J Neurochem 2023; 164:77-93. [PMID: 36326589 PMCID: PMC10099669 DOI: 10.1111/jnc.15718] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 10/28/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022]
Abstract
Mutations in the human Superoxide dismutase 1 (hSOD1) gene are well-established cause of the motor neuron disease ALS. Patients and transgenic (Tg) ALS model mice carrying mutant variants develop hSOD1 aggregates in the CNS. We have identified two hSOD1 aggregate strains, which both transmit spreading template-directed aggregation and premature fatal paralysis when inoculated into adult transgenic mice. This prion-like spread of aggregation could be a primary disease mechanism in SOD1-induced ALS. Human SOD1 aggregation has been studied extensively both in cultured cells and under various conditions in vitro. To determine how the structure of aggregates formed in these model systems related to disease-associated aggregates in the CNS, we used a binary epitope-mapping assay to examine aggregates of hSOD1 variants G93A, G85R, A4V, D90A, and G127X formed in vitro, in four different cell lines and in the CNS of Tg mice. We found considerable variability between replicate sets of in vitro-generated aggregates. In contrast, there was a high similarity between replicates of a given hSOD1 mutant in a given cell line, but pronounced variations between different hSOD1 mutants and different cell lines in both structures and amounts of aggregates formed. The aggregates formed in vitro or in cultured cells did not replicate the aggregate strains that arise in the CNS. Our findings suggest that the distinct aggregate morphologies in the CNS could result from a micro-environment with stringent quality control combined with second-order selection by spreading ability. Explorations of pathogenesis and development of therapeutics should be conducted in models that replicate aggregate structures forming in the CNS.
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Affiliation(s)
- Ulrika Nordström
- Department of Clinical Science, Neurosciences, Umeå University, Umeå, Sweden
| | - Lisa Lang
- Department of Biochemistry and Biophysics, Arrhenius Laboratories of Natural Sciences, Stockholm University, Stockholm, Sweden
| | - Elaheh Ekhtiari Bidhendi
- Department of Clinical Science, Neurosciences, Umeå University, Umeå, Sweden.,Department of Medical Biosciences, Clinical Chemistry, Umeå University, Umeå, Sweden
| | - Per Zetterström
- Department of Medical Biosciences, Clinical Chemistry, Umeå University, Umeå, Sweden
| | - Mikael Oliveberg
- Department of Biochemistry and Biophysics, Arrhenius Laboratories of Natural Sciences, Stockholm University, Stockholm, Sweden
| | - Jens Danielsson
- Department of Biochemistry and Biophysics, Arrhenius Laboratories of Natural Sciences, Stockholm University, Stockholm, Sweden
| | - Peter M Andersen
- Department of Clinical Science, Neurosciences, Umeå University, Umeå, Sweden
| | - Stefan L Marklund
- Department of Medical Biosciences, Clinical Chemistry, Umeå University, Umeå, Sweden
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4
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Bian X, Zhuang X, Xing J, Liu S, Liu Z, Song F. Native Mass Spectrometry Coupled to Spectroscopic Methods to Investigate the Effect of Soybean Isoflavones on Structural Stability and Aggregation of Zinc Deficient and Metal-Free Superoxide Dismutase. Molecules 2022; 27:7303. [PMID: 36364128 PMCID: PMC9654870 DOI: 10.3390/molecules27217303] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/23/2022] [Accepted: 10/24/2022] [Indexed: 12/26/2023] Open
Abstract
The deficiency or wrong combination of metal ions in Cu, Zn-superoxide dismutase (SOD1), is regarded as one of the main factors causing the aggregation of SOD1 and then inducing amyotrophic lateral sclerosis (ALS). A ligands-targets screening process based on native electrospray ionization ion mobility mass spectrometry (ESI-IMS-MS) was established in this study. Four glycosides including daidzin, sophoricoside, glycitin, and genistin were screened out from seven soybean isoflavone compounds and were found to interact with zinc-deficient or metal-free SOD1. The structure and conformation stability of metal-free and zinc-deficient SOD1 and their complexes with the four glycosides was investigated by collision-induced dissociation (CID) and collision-induced unfolding (CIU). The four glycosides could strongly bind to the metal-free and copper recombined SOD1 and enhance the folding stability of these proteins. Additionally, the ThT fluorescence assay showed that these glycosides could inhibit the toxic aggregation of the zinc-deficient or metal-free SOD1. The competitive interaction experiments together with molecular docking indicate that glycitin, which showed the best stabilizing effects, binds with SOD1 between β-sheet 6 and loop IV. In short, this study provides good insight into the relationship between inhibitors and different SOD1s.
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Affiliation(s)
- Xinyu Bian
- State Key Laboratory of Electroanalytical Chemistry & Jilin Province Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230029, China
| | - Xiaoyu Zhuang
- Experiment Center for Science and Technology, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Junpeng Xing
- State Key Laboratory of Electroanalytical Chemistry & Jilin Province Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Shu Liu
- State Key Laboratory of Electroanalytical Chemistry & Jilin Province Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230029, China
| | - Zhiqiang Liu
- State Key Laboratory of Electroanalytical Chemistry & Jilin Province Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230029, China
| | - Fengrui Song
- State Key Laboratory of Electroanalytical Chemistry & Jilin Province Key Laboratory of Chinese Medicine Chemistry and Mass Spectrometry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
- School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230029, China
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5
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Wang LQ, Ma Y, Yuan HY, Zhao K, Zhang MY, Wang Q, Huang X, Xu WC, Dai B, Chen J, Li D, Zhang D, Wang Z, Zou L, Yin P, Liu C, Liang Y. Cryo-EM structure of an amyloid fibril formed by full-length human SOD1 reveals its conformational conversion. Nat Commun 2022; 13:3491. [PMID: 35715417 PMCID: PMC9205981 DOI: 10.1038/s41467-022-31240-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 06/09/2022] [Indexed: 11/23/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease. Misfolded Cu, Zn-superoxide dismutase (SOD1) has been linked to both familial and sporadic ALS. SOD1 fibrils formed in vitro share toxic properties with ALS inclusions. Here we produced cytotoxic amyloid fibrils from full-length apo human SOD1 under reducing conditions and determined the atomic structure using cryo-EM. The SOD1 fibril consists of a single protofilament with a left-handed helix. The fibril core exhibits a serpentine fold comprising N-terminal segment (residues 3–55) and C-terminal segment (residues 86–153) with an intrinsic disordered segment. The two segments are zipped up by three salt bridge pairs. By comparison with the structure of apo SOD1 dimer, we propose that eight β-strands (to form a β-barrel) and one α-helix in the subunit of apo SOD1 convert into thirteen β-strands stabilized by five hydrophobic cavities in the SOD1 fibril. Our data provide insights into how SOD1 converts between structurally and functionally distinct states. Misfolded SOD1 has been linked to both familial and sporadic ALS. Here the authors have determined the cryo-EM structure of SOD1 fibrils, providing insights into the conversion of SOD1 from its immature form into an aggregated form during pathogenesis of ALS.
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Affiliation(s)
- Li-Qiang Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, China.,Wuhan University Shenzhen Research Institute, 518057, Shenzhen, China
| | - Yeyang Ma
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 201210, Shanghai, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Han-Ye Yuan
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, China.,Wuhan University Shenzhen Research Institute, 518057, Shenzhen, China
| | - Kun Zhao
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 201210, Shanghai, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Mu-Ya Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, China.,Wuhan University Shenzhen Research Institute, 518057, Shenzhen, China
| | - Qiang Wang
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, 430070, Wuhan, China
| | - Xi Huang
- Department of Neurology, the Second Clinical Medical College, Jinan University (Shenzhen People's Hospital), 518020, Shenzhen, China
| | - Wen-Chang Xu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, China
| | - Bin Dai
- Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Jie Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, China.,Wuhan University Shenzhen Research Institute, 518057, Shenzhen, China
| | - Dan Li
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Institutes, Shanghai Jiao Tong University, 200030, Shanghai, China.,Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Delin Zhang
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, 430070, Wuhan, China
| | - Zhengzhi Wang
- School of Civil Engineering, Wuhan University, 430072, Wuhan, China
| | - Liangyu Zou
- Department of Neurology, the Second Clinical Medical College, Jinan University (Shenzhen People's Hospital), 518020, Shenzhen, China
| | - Ping Yin
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, 430070, Wuhan, China
| | - Cong Liu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 201210, Shanghai, China.
| | - Yi Liang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, China. .,Wuhan University Shenzhen Research Institute, 518057, Shenzhen, China.
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6
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Bian X, Zhuang X, Zheng Z, Liu S, Liu Z, Song F. Unfolding and aggregation of oxidized metal-deficient superoxide dismutase and isoflavone inhibition based on ion mobility mass spectrometry and ThT fluorescence assay. Arch Biochem Biophys 2022; 727:109306. [DOI: 10.1016/j.abb.2022.109306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 11/02/2022]
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7
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Ziaunys M, Mikalauskaite K, Veiveris D, Sakalauskas A, Smirnovas V. Superoxide dismutase-1 alters the rate of prion protein aggregation and resulting fibril conformation. Arch Biochem Biophys 2022; 715:109096. [PMID: 34848178 DOI: 10.1016/j.abb.2021.109096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 11/02/2022]
Abstract
The assembly of amyloidogenic proteins into highly-structured fibrillar aggregates is related to the onset and progression of several amyloidoses, including neurodegenerative Alzheimer's or Parkinson's diseases. Despite years of research and a general understanding of the process of such aggregate formation, there are currently still very few drugs and treatment modalities available. One of the factors that is relatively insufficiently understood is the cross-interaction between different amyloid-forming proteins. In recent years, it has been shown that several of these proteins or their aggregates can alter each other's fibrillization properties, however, there are still many unknowns in the amyloid interactome. In this work, we examine the interaction between amyloid disease-related prion protein and superoxide dismutase-1. We show that not only does superoxide dismutase-1 increase the lag time of prion protein fibril formation, but it also changes the conformation of the resulting aggregates.
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Affiliation(s)
- Mantas Ziaunys
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania.
| | - Kamile Mikalauskaite
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Dominykas Veiveris
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Andrius Sakalauskas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Vytautas Smirnovas
- Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
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8
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Baumer KM, Cook CD, Zahler CT, Beard AA, Chen Z, Koone JC, Dashnaw CM, Villacob RA, Solouki T, Wood JL, Borchelt DR, Shaw BF. Supercharging Prions via Amyloid‐Selective Lysine Acetylation. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Katelyn M. Baumer
- Department of Chemistry and Biochemistry Baylor University Waco TX USA
| | | | - Collin T. Zahler
- Department of Chemistry and Biochemistry Baylor University Waco TX USA
| | | | - Zhijuan Chen
- Department of Neuroscience University of Florida Gainesville FL USA
| | - Jordan C. Koone
- Department of Chemistry and Biochemistry Baylor University Waco TX USA
| | - Chad M. Dashnaw
- Department of Chemistry and Biochemistry Baylor University Waco TX USA
| | - Raul A. Villacob
- Department of Chemistry and Biochemistry Baylor University Waco TX USA
| | - Touradj Solouki
- Department of Chemistry and Biochemistry Baylor University Waco TX USA
| | - John L. Wood
- Department of Chemistry and Biochemistry Baylor University Waco TX USA
| | | | - Bryan F. Shaw
- Department of Chemistry and Biochemistry Baylor University Waco TX USA
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9
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Baumer KM, Cook CD, Zahler CT, Beard AA, Chen Z, Koone JC, Dashnaw CM, Villacob RA, Solouki T, Wood JL, Borchelt DR, Shaw BF. Supercharging Prions via Amyloid-Selective Lysine Acetylation. Angew Chem Int Ed Engl 2021; 60:15069-15079. [PMID: 33876528 DOI: 10.1002/anie.202103548] [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: 03/11/2021] [Indexed: 11/10/2022]
Abstract
Repulsive electrostatic forces between prion-like proteins are a barrier against aggregation. In neuropharmacology, however, a prion's net charge (Z) is not a targeted parameter. Compounds that selectively boost prion Z remain unreported. Here, we synthesized compounds that amplified the negative charge of misfolded superoxide dismutase-1 (SOD1) by acetylating lysine-NH3 + in amyloid-SOD1, without acetylating native-SOD1. Compounds resembled a "ball and chain" mace: a rigid amyloid-binding "handle" (benzothiazole, stilbene, or styrylpyridine); an aryl ester "ball"; and a triethylene glycol chain connecting ball to handle. At stoichiometric excess, compounds acetylated up to 9 of 11 lysine per misfolded subunit (ΔZfibril =-8100 per 103 subunits). Acetylated amyloid-SOD1 seeded aggregation more slowly than unacetylated amyloid-SOD1 in vitro and organotypic spinal cord (these effects were partially due to compound binding). Compounds exhibited reactivity with other amyloid and non-amyloid proteins (e.g., fibrillar α-synuclein was peracetylated; serum albumin was partially acetylated; carbonic anhydrase was largely unacetylated).
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Affiliation(s)
- Katelyn M Baumer
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Christopher D Cook
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Collin T Zahler
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Alexandra A Beard
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Zhijuan Chen
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Jordan C Koone
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Chad M Dashnaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Raul A Villacob
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Touradj Solouki
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - John L Wood
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - David R Borchelt
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Bryan F Shaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
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10
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Ayers JI, Xu G, Dillon K, Lu Q, Chen Z, Beckman J, Moreno-Romero AK, Zamora DL, Galaleldeen A, Borchelt DR. Variation in the vulnerability of mice expressing human superoxide dismutase 1 to prion-like seeding: a study of the influence of primary amino acid sequence. Acta Neuropathol Commun 2021; 9:92. [PMID: 34016165 PMCID: PMC8139116 DOI: 10.1186/s40478-021-01191-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/03/2021] [Indexed: 11/24/2022] Open
Abstract
Misfolded forms of superoxide dismutase 1 (SOD1) with mutations associated with familial amyotrophic lateral sclerosis (fALS) exhibit prion characteristics, including the ability to act as seeds to accelerate motor neuron disease in mouse models. A key feature of infectious prion seeding is that the efficiency of transmission is governed by the primary sequence of prion protein (PrP). Isologous seeding, where the sequence of the PrP in the seed matches that of the host, is generally much more efficient than when there is a sequence mis-match. Here, we used paradigms in which mutant SOD1 seeding homogenates were injected intraspinally in newborn mice or into the sciatic nerve of adult mice, to assess the influence of SOD1 primary sequence on seeding efficiency. We observed a spectrum of seeding efficiencies depending upon both the SOD1 expressed by mice injected with seeds and the origin of the seed preparations. Mice expressing WT human SOD1 or the disease variant G37R were resistant to isologous seeding. Mice expressing G93A SOD1 were also largely resistant to isologous seeding, with limited success in one line of mice that express at low levels. By contrast, mice expressing human G85R-SOD1 were highly susceptible to isologous seeding but resistant to heterologous seeding by homogenates from paralyzed mice over-expressing mouse SOD1-G86R. In other seeding experiments with G85R SOD1:YFP mice, we observed that homogenates from paralyzed animals expressing the H46R or G37R variants of human SOD1 were less effective than seeds prepared from mice expressing the human G93A variant. These sequence mis-match effects were less pronounced when we used purified recombinant SOD1 that had been fibrilized in vitro as the seeding preparation. Collectively, our findings demonstrate diversity in the abilities of ALS variants of SOD1 to initiate or sustain prion-like propagation of misfolded conformations that produce motor neuron disease.
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11
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Koo BK, Munroe W, Gralla EB, Valentine JS, Whitelegge JP. A Novel SOD1 Intermediate Oligomer, Role of Free Thiols and Disulfide Exchange. Front Neurosci 2021; 14:619279. [PMID: 33679289 PMCID: PMC7930385 DOI: 10.3389/fnins.2020.619279] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/24/2020] [Indexed: 11/16/2022] Open
Abstract
Wild-type human SOD1 forms a highly conserved intra-molecular disulfide bond between C57-C146, and in its native state is greatly stabilized by binding one copper and one zinc atom per monomer rendering the protein dimeric. Loss of copper extinguishes dismutase activity and destabilizes the protein, increasing accessibility of the disulfide with monomerization accompanying disulfide reduction. A further pair of free thiols exist at C6 and C111 distant from metal binding sites, raising the question of their function. Here we investigate their role in misfolding of SOD1 along a pathway that leads to formation of amyloid fibrils. We present the seeding reaction of a mutant SOD1 lacking free sulfhydryl groups (AS-SOD1) to exclude variables caused by these free cysteines. Completely reduced fibril seeds decreasing the kinetic barrier to cleave the highly conserved intramolecular disulfide bond, and accelerating SOD1 reduction and initiation of fibrillation. Presence or absence of the pair of free thiols affects kinetics of fibrillation. Previously, we showed full maturation with both Cu and Zn prevents this behavior while lack of Cu renders sensitivity to fibrillation, with presence of the native disulfide bond modulating this propensity much more strongly than presence of Zn or dimerization. Here we further investigate the role of reduction of the native C57-C146 disulfide bond in fibrillation of wild-type hSOD1, firstly through removal of free thiols by paired mutations C6A, C111S (AS-SOD1), and secondly in seeded fibrillation reactions modulated by reductant tris (2-carboxyethyl) phosphine (TCEP). Fibrillation of AS-SOD1 was dependent upon disulfide reduction and showed classic lag and exponential growth phases compared with wild-type hSOD1 whose fibrillation trajectories were typically somewhat perturbed. Electron microscopy showed that AS-SOD1 formed classic fibrils while wild-type fibrillation reactions showed the presence of smaller “sausage-like” oligomers in addition to fibrils, highlighting the potential for mixed disulfides involving C6/C111 to disrupt efficient fibrillation. Seeding by addition of sonicated fibrils lowered the TCEP concentration needed for fibrillation in both wild-type and AS-SOD1 providing evidence for template-driven structural disturbance that elevated susceptibility to reduction and thus propensity to fibrillate.
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Affiliation(s)
- Bon-Kyung Koo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
| | - William Munroe
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
| | - Edith B Gralla
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
| | - Joan Selverstone Valentine
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
| | - Julian P Whitelegge
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States.,The Pasarow Mass Spectrometry Laboratory, David Geffen School of Medicine, NPI-Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, United States
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12
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McAlary L, Chew YL, Lum JS, Geraghty NJ, Yerbury JJ, Cashman NR. Amyotrophic Lateral Sclerosis: Proteins, Proteostasis, Prions, and Promises. Front Cell Neurosci 2020; 14:581907. [PMID: 33328890 PMCID: PMC7671971 DOI: 10.3389/fncel.2020.581907] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is characterized by the progressive degeneration of the motor neurons that innervate muscle, resulting in gradual paralysis and culminating in the inability to breathe or swallow. This neuronal degeneration occurs in a spatiotemporal manner from a point of onset in the central nervous system (CNS), suggesting that there is a molecule that spreads from cell-to-cell. There is strong evidence that the onset and progression of ALS pathology is a consequence of protein misfolding and aggregation. In line with this, a hallmark pathology of ALS is protein deposition and inclusion formation within motor neurons and surrounding glia of the proteins TAR DNA-binding protein 43, superoxide dismutase-1, or fused in sarcoma. Collectively, the observed protein aggregation, in conjunction with the spatiotemporal spread of symptoms, strongly suggests a prion-like propagation of protein aggregation occurs in ALS. In this review, we discuss the role of protein aggregation in ALS concerning protein homeostasis (proteostasis) mechanisms and prion-like propagation. Furthermore, we examine the experimental models used to investigate these processes, including in vitro assays, cultured cells, invertebrate models, and murine models. Finally, we evaluate the therapeutics that may best prevent the onset or spread of pathology in ALS and discuss what lies on the horizon for treating this currently incurable disease.
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Affiliation(s)
- Luke McAlary
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Yee Lian Chew
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Jeremy Stephen Lum
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Nicholas John Geraghty
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Justin John Yerbury
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Neil R. Cashman
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
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13
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Niu B, Mackness BC, Zitzewitz JA, Matthews CR, Gross ML. Trifluoroethanol Partially Unfolds G93A SOD1 Leading to Protein Aggregation: A Study by Native Mass Spectrometry and FPOP Protein Footprinting. Biochemistry 2020; 59:3650-3659. [PMID: 32924445 DOI: 10.1021/acs.biochem.0c00425] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Misfolding of Cu, Zn superoxide dismutase (SOD1) variants may lead to protein aggregation and ultimately amyotrophic lateral sclerosis (ALS). The mechanism and protein conformational changes during this process are complex and remain unclear. To study SOD1 variant aggregation at the molecular level and in solution, we chemically induced aggregation of a mutant variant (G93A SOD1) with trifluoroethanol (TFE) and used both native mass spectrometry (MS) to analyze the intact protein and fast photochemical oxidation of proteins (FPOP) to characterize the structural changes induced by TFE. We found partially unfolded G93A SOD1 monomers prior to oligomerization and identified regions of the N-terminus, C-terminus, and strands β5, β6 accountable for the partial unfolding. We propose that exposure of hydrophobic interfaces of these unstructured regions serves as a precursor to aggregation. Our results provide a possible mechanism and molecular basis for ALS-linked SOD1 misfolding and aggregation.
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Affiliation(s)
- Ben Niu
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Brian C Mackness
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, United States
| | - Jill A Zitzewitz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, United States
| | - C Robert Matthews
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, United States
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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14
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McAlary L, Yerbury JJ, Cashman NR. The prion-like nature of amyotrophic lateral sclerosis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 175:261-296. [PMID: 32958236 DOI: 10.1016/bs.pmbts.2020.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The misfolding, aggregation, and deposition of specific proteins is the key hallmark of most progressive neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis (ALS). ALS is characterized by the rapid and progressive degenerations of motor neurons in the spinal cord and motor cortex, resulting in paralysis of those who suffer from it. Pathologically, there are three major aggregating proteins associated with ALS, including TAR DNA-binding protein of 43kDa (TDP-43), superoxide dismutase-1 (SOD1), and fused in sarcoma (FUS). While there are ALS-associated mutations found in each of these proteins, the most prevalent aggregation pathology is that of wild-type TDP-43 (97% of cases), with the remaining split between mutant forms of SOD1 (~2%) and FUS (~1%). Considering the progressive nature of ALS and its association with the aggregation of specific proteins, a growing notion is that the spread of pathology and symptoms can be explained by a prion-like mechanism. Prion diseases are a group of highly infectious neurodegenerative disorders caused by the misfolding, aggregation, and spread of a transmissible conformer of prion protein (PrP). Pathogenic PrP is capable of converting healthy PrP into a toxic form through template-directed misfolding. Application of this finding to other neurodegenerative disorders, and in particular ALS, has revolutionized our understanding of cause and progression of these disorders. In this chapter, we first provide a background on ALS pathology and genetic origin. We then detail and discuss the evidence supporting a prion-like propagation of protein misfolding and aggregation in ALS with a particular focus on SOD1 and TDP-43 as these are the most well-established models in the field.
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Affiliation(s)
- L McAlary
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia; Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - J J Yerbury
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia; Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - N R Cashman
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.
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15
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Musteikyte G, Ziaunys M, Smirnovas V. Methylene blue inhibits nucleation and elongation of SOD1 amyloid fibrils. PeerJ 2020; 8:e9719. [PMID: 32864220 PMCID: PMC7430317 DOI: 10.7717/peerj.9719] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/23/2020] [Indexed: 12/14/2022] Open
Abstract
Protein aggregation into highly-structured amyloid fibrils is linked to several neurodegenerative diseases. Such fibril formation by superoxide dismutase I (SOD1) is considered to be related to amyotrophic lateral sclerosis, a late-onset and fatal disorder. Despite much effort and the discovery of numerous anti-amyloid compounds, no effective cure or treatment is currently available. Methylene blue (MB), a phenothiazine dye, has been shown to modulate the aggregation of multiple amyloidogenic proteins. In this work we show its ability to inhibit both the spontaneous amyloid aggregation of SOD1 as well as elongation of preformed fibrils.
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Affiliation(s)
- Greta Musteikyte
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom.,Life Sciences Center, Institute of Biotechnology, Vilnius University, Vilnius, Lithuania
| | - Mantas Ziaunys
- Life Sciences Center, Institute of Biotechnology, Vilnius University, Vilnius, Lithuania
| | - Vytautas Smirnovas
- Life Sciences Center, Institute of Biotechnology, Vilnius University, Vilnius, Lithuania
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16
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Le Gall L, Anakor E, Connolly O, Vijayakumar UG, Duddy WJ, Duguez S. Molecular and Cellular Mechanisms Affected in ALS. J Pers Med 2020; 10:E101. [PMID: 32854276 PMCID: PMC7564998 DOI: 10.3390/jpm10030101] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/17/2020] [Accepted: 08/22/2020] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a terminal late-onset condition characterized by the loss of upper and lower motor neurons. Mutations in more than 30 genes are associated to the disease, but these explain only ~20% of cases. The molecular functions of these genes implicate a wide range of cellular processes in ALS pathology, a cohesive understanding of which may provide clues to common molecular mechanisms across both familial (inherited) and sporadic cases and could be key to the development of effective therapeutic approaches. Here, the different pathways that have been investigated in ALS are summarized, discussing in detail: mitochondrial dysfunction, oxidative stress, axonal transport dysregulation, glutamate excitotoxicity, endosomal and vesicular transport impairment, impaired protein homeostasis, and aberrant RNA metabolism. This review considers the mechanistic roles of ALS-associated genes in pathology, viewed through the prism of shared molecular pathways.
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Affiliation(s)
- Laura Le Gall
- Northern Ireland Center for Stratified/Personalised Medicine, Biomedical Sciences Research Institute, Ulster University, Derry-Londonderry BT47, UK; (L.L.G.); (E.A.); (O.C.); (U.G.V.); (W.J.D.)
- NIHR Biomedical Research Centre, University College London, Great Ormond Street Institute of Child Health and Great Ormond Street Hospital NHS Trust, London WC1N 1EH, UK
| | - Ekene Anakor
- Northern Ireland Center for Stratified/Personalised Medicine, Biomedical Sciences Research Institute, Ulster University, Derry-Londonderry BT47, UK; (L.L.G.); (E.A.); (O.C.); (U.G.V.); (W.J.D.)
| | - Owen Connolly
- Northern Ireland Center for Stratified/Personalised Medicine, Biomedical Sciences Research Institute, Ulster University, Derry-Londonderry BT47, UK; (L.L.G.); (E.A.); (O.C.); (U.G.V.); (W.J.D.)
| | - Udaya Geetha Vijayakumar
- Northern Ireland Center for Stratified/Personalised Medicine, Biomedical Sciences Research Institute, Ulster University, Derry-Londonderry BT47, UK; (L.L.G.); (E.A.); (O.C.); (U.G.V.); (W.J.D.)
| | - William J. Duddy
- Northern Ireland Center for Stratified/Personalised Medicine, Biomedical Sciences Research Institute, Ulster University, Derry-Londonderry BT47, UK; (L.L.G.); (E.A.); (O.C.); (U.G.V.); (W.J.D.)
| | - Stephanie Duguez
- Northern Ireland Center for Stratified/Personalised Medicine, Biomedical Sciences Research Institute, Ulster University, Derry-Londonderry BT47, UK; (L.L.G.); (E.A.); (O.C.); (U.G.V.); (W.J.D.)
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17
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Malik R, Corrales C, Linsenmeier M, Alalami H, Sepanj N, Bitan G. Examination of SOD1 aggregation modulators and their effect on SOD1 enzymatic activity as a proxy for potential toxicity. FASEB J 2020; 34:11957-11969. [PMID: 32701214 DOI: 10.1096/fj.202000948r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 06/17/2020] [Accepted: 06/24/2020] [Indexed: 01/08/2023]
Abstract
Small-molecule inhibitors of abnormal protein self-assembly are promising candidates for developing therapy against proteinopathies. Such compounds have been examined primarily as inhibitors of amyloid β-protein (Aβ), whereas testing of inhibitors of other amyloidogenic proteins has lagged behind. An important issue with screening compound libraries is that although an inhibitor suitable for therapy must be both effective and nontoxic, typical screening focuses on efficacy, whereas safety typically is tested at a later stage using cells and/or animals. In addition, typical thioflavin T (ThT)-fluorescence-based screens use the final fluorescence value as a readout, potentially missing important kinetic information. Here, we examined potential inhibitors of superoxide dismutase 1 (SOD1) using ThT-fluorescence including the different phases of fluorescence change and added a parallel screen of SOD1 activity as a potential proxy for compound toxicity. Some compounds previously reported to inhibit other amyloidogenic proteins also inhibited SOD1 aggregation at low micromolar concentrations, whereas others were ineffective. Analysis of the lag phase and exponential slope added important information that could help exclude false-positive or false-negative results. SOD1 was highly resistant to inhibition of its activity, and therefore, did not have the necessary sensitivity to serve as a proxy for examining potential toxicity.
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Affiliation(s)
- Ravinder Malik
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA, USA
| | - Christian Corrales
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA, USA
| | - Miriam Linsenmeier
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA, USA
| | - Huda Alalami
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA, USA
| | - Niki Sepanj
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA, USA
| | - Gal Bitan
- Department of Neurology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, CA, USA.,Brain Research Institute, University of California at Los Angeles, Los Angeles, CA, USA.,Molecular Biology Institute, University of California at Los Angeles, Los Angeles, CA, USA
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18
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Nucleation and kinetics of SOD1 aggregation in human cells for ALS1. Mol Cell Biochem 2020; 466:117-128. [PMID: 32056106 DOI: 10.1007/s11010-020-03693-y] [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: 03/11/2019] [Accepted: 01/29/2020] [Indexed: 01/09/2023]
Abstract
Aberrant structural formations of Cu/Zn superoxide dismutase enzyme (SOD1) are the probable mechanism by which circumscribed mutations in the SOD1 gene cause familial amyotrophic lateral sclerosis (ALS1). SOD1 forms aberrant structures which can proceed by nucleation to insoluble aggregates. Here, the SOD1 aggregation reaction was investigated predominantly by time-course studies on ALS1 variants G85R, G37R, D101G, and D101N in human embryonic kidney cells (HEK293FT), with analysis by detergent ultracentrifugation extractions and high-resolution PAGE methodologies. Nucleation was found to be pseudo-zeroth order and dependent on time and concentration at constant 37.0 °C and pH 7.4. The predominant subsets of the total SOD1 expression set which comprised the nucleation phase were both soluble and insoluble inactive monomers, trimers, and hexamers with reduced intra-disulfide bonds. Superoxide exposure via paraquat initiated the formation of SOD1 trimers in untransfected SH-SY5Y cells and increased the aggregation propensity of G85R in HEK293FT. These data show the kinetic formation of aberrant SOD1 subsets implicated in ALS1 and indicate that superoxide substrate may initiate its radical polymerization. In an instance of the utility of methodological reductionism in molecular theory: though many ALS1 variants retain their global enzymatic activity, the SOD1 subsets most implicated in causing ALS1 do not retain their specific activity.
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19
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Baumer KM, Koone JC, Shaw BF. Kinetic Variability in Seeded Formation of ALS-Linked SOD1 Fibrils Across Multiple Generations. ACS Chem Neurosci 2020; 11:304-313. [PMID: 31895541 DOI: 10.1021/acschemneuro.9b00464] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The unseeded aggregation of superoxide dismutase-1 (SOD1) into amyloid-like fibrils occurs stochastically in vitro and in vivo, that is, isolated populations of SOD1 proteins (within microplate wells or living cells) self-assemble into amyloid at rates that span a probability distribution. This stochasticity has been attributed to variable degrees of monomer depletion by competing pathways of amorphous and fibrillar aggregation (inter alia). Here, microplate-based thioflavin-T (ThT) fluorescence assays were performed at high iteration (∼300) to establish whether this observed stochasticity persists when progenitor ("parent") SOD1 fibrils are used to seed the formation of multiple generations of progeny fibrils (daughter, granddaughter, and great-granddaughter fibrils). Populations of progenitor fibrils formed stochastically at different rates and fluorescence intensity, however, progeny fibrils formed at more similar rates regardless of the formation rate of the progenitor fibril. For example, populations of progenitor fibrils that formed with a lag time of ∼30 h or ∼15 h both produced progeny fibrils with lag times of ∼8 h. Likewise, populations of progenitor fibrils with high or low maximum fluorescence (e.g., ∼450 or ∼75 A.U.) both produced progeny fibrils with more similar maximum fluorescence (∼125 A.U.). The rate of propagation was found to be more dependent on monomer concentration than seed concentration. These results can be rationalized by classical rate laws for primary nucleation and monomer-dependent secondary nucleation. We also find that the seeding propensity of some "families" of in vitro grown fibrils exhibit a finite lifetime (similar to that observed in the seeding of small molecule crystals and colloids). The single biological takeaway of this study is that the concentration of native SOD1 in a cell can have a stronger effect on rates of seeded aggregation than the concentration of prion-like seed that infected the cell.
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Affiliation(s)
- Katelyn M Baumer
- Department of Chemistry and Biochemistry , Baylor University , Waco , Texas 76706 , United States
| | - Jordan C Koone
- Department of Chemistry and Biochemistry , Baylor University , Waco , Texas 76706 , United States
| | - Bryan F Shaw
- Department of Chemistry and Biochemistry , Baylor University , Waco , Texas 76706 , United States
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20
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Crown A, McAlary L, Fagerli E, Brown H, Yerbury JJ, Galaleldeen A, Cashman NR, Borchelt DR, Ayers JI. Tryptophan residue 32 in human Cu-Zn superoxide dismutase modulates prion-like propagation and strain selection. PLoS One 2020; 15:e0227655. [PMID: 31999698 PMCID: PMC6991973 DOI: 10.1371/journal.pone.0227655] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/21/2019] [Indexed: 12/14/2022] Open
Abstract
Mutations in Cu/Zn superoxide dismutase 1 (SOD1) associated with familial amyotrophic lateral sclerosis cause the protein to aggregate via a prion-like process in which soluble molecules are recruited to aggregates by conformational templating. These misfolded SOD1 proteins can propagate aggregation-inducing conformations across cellular membranes. Prior studies demonstrated that mutation of a Trp (W) residue at position 32 to Ser (S) suppresses the propagation of misfolded conformations between cells, whereas other studies have shown that mutation of Trp 32 to Phe (F), or Cys 111 to Ser, can act in cis to attenuate aggregation of mutant SOD1. By expressing mutant SOD1 fused with yellow fluorescent protein (YFP), we compared the relative ability of these mutations to modulate the formation of inclusions by ALS-mutant SOD1 (G93A and G85R). Only mutation of Trp 32 to Ser persistently reduced the formation of the amorphous inclusions that form in these cells, consistent with the idea that a Ser at position 32 inhibits templated propagation of aggregation prone conformations. To further test this idea, we produced aggregated fibrils of recombinant SOD1-W32S in vitro and injected them into the spinal cords of newborn mice expressing G85R-SOD1: YFP. The injected mice developed an earlier onset paralysis with a frequency similar to mice injected with WT SOD1 fibrils, generating a strain of misfolded SOD1 that produced highly fibrillar inclusion pathology. These findings suggest that the effect of Trp 32 in modulating the propagation of misfolded SOD1 conformations may be dependent upon the “strain” of the conformer that is propagating.
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Affiliation(s)
- Anthony Crown
- Center for Translational Research in Neurodegenerative Disease, SantaFe HealthCare Alzheimer’s Disease Research Center, Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida, United States of America
| | - Luke McAlary
- Molecular Horizons and School of Chemistry & Molecular Bioscience, University of Wollongong, New South Wales, Australia
- Illawarra Health and Medical Research Institute, School of Chemistry & Molecular Bioscience, University of Wollongong, New South Wales, Australia
| | - Eric Fagerli
- Center for Translational Research in Neurodegenerative Disease, SantaFe HealthCare Alzheimer’s Disease Research Center, Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida, United States of America
| | - Hilda Brown
- Center for Translational Research in Neurodegenerative Disease, SantaFe HealthCare Alzheimer’s Disease Research Center, Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida, United States of America
| | - Justin J. Yerbury
- Molecular Horizons and School of Chemistry & Molecular Bioscience, University of Wollongong, New South Wales, Australia
- Illawarra Health and Medical Research Institute, School of Chemistry & Molecular Bioscience, University of Wollongong, New South Wales, Australia
| | - Ahmad Galaleldeen
- Department of Biological Sciences, St. Mary’s University, San Antonio, Texas, United States of America
| | - Neil R. Cashman
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada
| | - David R. Borchelt
- Center for Translational Research in Neurodegenerative Disease, SantaFe HealthCare Alzheimer’s Disease Research Center, Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida, United States of America
| | - Jacob I. Ayers
- Center for Translational Research in Neurodegenerative Disease, SantaFe HealthCare Alzheimer’s Disease Research Center, Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida, United States of America
- Institute for Neurodegenerative Disease, University of California, San Francisco, California, United States of America
- * E-mail:
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21
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Abstract
Few proteins have come under such intense scrutiny as superoxide dismutase-1 (SOD1). For almost a century, scientists have dissected its form, function and then later its malfunction in the neurodegenerative disease amyotrophic lateral sclerosis (ALS). We now know SOD1 is a zinc and copper metalloenzyme that clears superoxide as part of our antioxidant defence and respiratory regulation systems. The possibility of reduced structural integrity was suggested by the first crystal structures of human SOD1 even before deleterious mutations in the sod1 gene were linked to the ALS. This concept evolved in the intervening years as an impressive array of biophysical studies examined the characteristics of mutant SOD1 in great detail. We now recognise how ALS-related mutations perturb the SOD1 maturation processes, reduce its ability to fold and reduce its thermal stability and half-life. Mutant SOD1 is therefore predisposed to monomerisation, non-canonical self-interactions, the formation of small misfolded oligomers and ultimately accumulation in the tell-tale insoluble inclusions found within the neurons of ALS patients. We have also seen that several post-translational modifications could push wild-type SOD1 down this toxic pathway. Recently we have come to view ALS as a prion-like disease where both the symptoms, and indeed SOD1 misfolding itself, are transmitted to neighbouring cells. This raises the possibility of intervention after the initial disease presentation. Several small-molecule and biologic-based strategies have been devised which directly target the SOD1 molecule to change the behaviour thought to be responsible for ALS. Here we provide a comprehensive review of the many biophysical advances that sculpted our view of SOD1 biology and the recent work that aims to apply this knowledge for therapeutic outcomes in ALS.
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22
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McAlary L, Plotkin SS, Yerbury JJ, Cashman NR. Prion-Like Propagation of Protein Misfolding and Aggregation in Amyotrophic Lateral Sclerosis. Front Mol Neurosci 2019; 12:262. [PMID: 31736708 PMCID: PMC6838634 DOI: 10.3389/fnmol.2019.00262] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/14/2019] [Indexed: 01/26/2023] Open
Abstract
The discovery that prion protein can misfold into a pathological conformation that encodes structural information capable of both propagation and inducing severe neuropathology has revolutionized our understanding of neurodegenerative disease. Many neurodegenerative diseases with a protein misfolding component are now classified as “prion-like” owing to the propagation of both symptoms and protein aggregation pathology in affected individuals. The neuromuscular disorder amyotrophic lateral sclerosis (ALS) is characterized by protein inclusions formed by either TAR DNA-binding protein of 43 kDa (TDP-43), Cu/Zn superoxide dismutase (SOD1), or fused in sarcoma (FUS), in both upper and lower motor neurons. Evidence from in vitro, cell culture, and in vivo studies has provided strong evidence to support the involvement of a prion-like mechanism in ALS. In this article, we review the evidence suggesting that prion-like propagation of protein aggregation is a primary pathomechanism in ALS, focusing on the key proteins and genes involved in disease (TDP-43, SOD1, FUS, and C9orf72). In each case, we discuss the evidence ranging from biophysical studies to in vivo examinations of prion-like spreading. We suggest that the idiopathic nature of ALS may stem from its prion-like nature and that elucidation of the specific propagating protein assemblies is paramount to developing effective therapies.
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Affiliation(s)
- Luke McAlary
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Steven S Plotkin
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada.,Genome Sciences and Technology Program, University of British Columbia, Vancouver, BC, Canada
| | - Justin J Yerbury
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia.,Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Neil R Cashman
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
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23
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Experimental Mutations in Superoxide Dismutase 1 Provide Insight into Potential Mechanisms Involved in Aberrant Aggregation in Familial Amyotrophic Lateral Sclerosis. G3-GENES GENOMES GENETICS 2019; 9:719-728. [PMID: 30622123 PMCID: PMC6404617 DOI: 10.1534/g3.118.200787] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mutations in more than 80 different positions in superoxide dismutase 1 (SOD1) have been associated with amyotrophic lateral sclerosis (fALS). There is substantial evidence that a common consequence of these mutations is to induce the protein to misfold and aggregate. How these mutations perturb native structure to heighten the propensity to misfold and aggregate is unclear. In the present study, we have mutagenized Glu residues at positions 40 and 133 that are involved in stabilizing the β-barrel structure of the native protein and a critical Zn binding domain, respectively, to examine how specific mutations may cause SOD1 misfolding and aggregation. Mutations associated with ALS as well as experimental mutations were introduced into these positions. We used an assay in which mutant SOD1 was fused to yellow fluorescent protein (SOD1:YFP) to visualize the formation of cytosolic inclusions by mutant SOD1. We then used existing structural data on SOD1, to predict how different mutations might alter local 3D conformation. Our findings reveal an association between mutant SOD1 aggregation and amino acid substitutions that are predicted to introduce steric strain, sometimes subtly, in the 3D conformation of the peptide backbone.
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24
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Huda N, Hossain M, Bhuyan AK. Complete observation of all structural, conformational, and fibrillation transitions of monomeric globular proteins at submicellar sodium dodecyl sulfate concentrations. Biopolymers 2019; 110:e23255. [PMID: 30633322 DOI: 10.1002/bip.23255] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/18/2018] [Accepted: 12/21/2018] [Indexed: 11/06/2022]
Abstract
Although considerable information is available regarding protein-sodium dodecyl sulfate (SDS) interactions, it is still unclear as to how much SDS is needed to denature proteins. The role of protein charge and micellar surfactant concentration on amyloid fibrillation is also unclear. This study reports on equilibrium measurements of SDS interaction with six model proteins and analyzes the results to obtain a general understanding of conformational breakdown, reorganization and restructuring of secondary structure, and entry into the amyloid fibrillar state. Significantly, all of these responses are entirely resolved at much lower than the critical micellar concentration (CMC) of SDS. Electrostatic interaction of the dodecyl sulfate anion (DS- ) with positive surface potential on the protein can completely unfold both secondary and tertiary structures, which is followed by protein chain restructuration to α-helices. All SDS-denatured proteins contain more α-helices than the corresponding native state. SDS interaction stochastically drives proteins to the aggregated fibrillar state.
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Affiliation(s)
- Noorul Huda
- School of Chemistry, University of Hyderabad, Hyderabad, India
| | - Mujahid Hossain
- School of Chemistry, University of Hyderabad, Hyderabad, India
| | - Abani K Bhuyan
- School of Chemistry, University of Hyderabad, Hyderabad, India
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25
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Abdolvahabi A, Rasouli S, Croom CM, Plewman DL. High-Throughput Microplate-Based Fluorescence Assays for Studying Stochastic Aggregation of Superoxide Dismutase-1. Methods Mol Biol 2019; 1873:93-108. [PMID: 30341605 DOI: 10.1007/978-1-4939-8820-4_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Investigating in vitro kinetics of superoxide dismutase-1 (SOD1) aggregation with high-throughput microplate-based assays provides valuable information regarding SOD1 pathogenesis in amyotrophic lateral sclerosis (ALS) and opens venues for the development of effective therapies. In this chapter, we first explain the step-by-step purification and demetallation of wild-type (WT) and ALS-variant SOD1 proteins from Saccharomyces cerevisiae (baker's yeast). We then describe the methodology for a microplate-based fluorescence assay that is used to study real-time kinetics of metal-free (apo)-SOD1 aggregation. This technique is highly sensitive, semiautomated, requires minimum modifications to protein, and produces a plethora of data in a short period of time. We also describe a new approach for extracting clinically relevant information from SOD1 aggregation data using Kaplan-Meier estimators.
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Affiliation(s)
- Alireza Abdolvahabi
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA.
| | - Sanaz Rasouli
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
- Institute of Biomedical Studies, Baylor University, Waco, TX, USA
| | - Corbin M Croom
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Devon L Plewman
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
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26
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Pokrishevsky E, McAlary L, Farrawell NE, Zhao B, Sher M, Yerbury JJ, Cashman NR. Tryptophan 32-mediated SOD1 aggregation is attenuated by pyrimidine-like compounds in living cells. Sci Rep 2018; 8:15590. [PMID: 30349065 PMCID: PMC6197196 DOI: 10.1038/s41598-018-32835-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 09/14/2018] [Indexed: 12/19/2022] Open
Abstract
Over 160 mutations in superoxide dismutase 1 (SOD1) are associated with familial amyotrophic lateral sclerosis (fALS), where the main pathological feature is deposition of SOD1 into proteinaceous cytoplasmic inclusions. We previously showed that the tryptophan residue at position 32 (W32) mediates the prion-like propagation of SOD1 misfolding in cells, and that a W32S substitution blocks this phenomenon. Here, we used in vitro protein assays to demonstrate that a W32S substitution in SOD1-fALS mutants significantly diminishes their propensity to aggregate whilst paradoxically decreasing protein stability. We also show SOD1-W32S to be resistant to seeded aggregation, despite its high abundance of unfolded protein. A cell-based aggregation assay demonstrates that W32S substitution significantly mitigates inclusion formation. Furthermore, this assay reveals that W32 in SOD1 is necessary for the formation of a competent seed for aggregation under these experimental conditions. Following the observed importance of W32 for aggregation, we established that treatment of living cells with the W32-interacting 5-Fluorouridine (5-FUrd), and its FDA approved analogue 5-Fluorouracil (5-FU), substantially attenuate inclusion formation similarly to W32S substitution. Altogether, we highlight W32 as a significant contributor to SOD1 aggregation, and propose that 5-FUrd and 5-FU present promising lead drug candidates for the treatment of SOD1-associated ALS.
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Affiliation(s)
- Edward Pokrishevsky
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, V6T 2B5, Canada
| | - Luke McAlary
- Faculty of Science Medicine and Health, University of Wollongong, Wollongong, NSW, 2522, Australia.,Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Natalie E Farrawell
- Faculty of Science Medicine and Health, University of Wollongong, Wollongong, NSW, 2522, Australia.,Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Beibei Zhao
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, V6T 2B5, Canada
| | - Mine Sher
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, V6T 2B5, Canada
| | - Justin J Yerbury
- Faculty of Science Medicine and Health, University of Wollongong, Wollongong, NSW, 2522, Australia. .,Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia.
| | - Neil R Cashman
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, V6T 2B5, Canada.
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27
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Jarand CW, Reed WF. On the Reproducibility of Early-Stage Thermally Induced and Contact-Stir-Induced Protein Aggregation. J Phys Chem B 2018; 122:9361-9372. [PMID: 30226382 DOI: 10.1021/acs.jpcb.8b07820] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Is aggregation kinetics for a protein under given conditions reproducible? Is aggregation inherently deterministic, stochastic, or even chaotic? Because protein aggregation in ex vivo formulations is complex, with many origins and manifestations, the question of aggregation reproducibility for a given protein, formulation, and stressor is of both fundamental and practical significance. This work concerns temperature-induced and contact-stir-induced aggregation of bovine serum albumin (BSA) and a monoclonal antibody (mAbX). It assesses reproducibility via early-stage aggregation rates (ARs) from light scattering. "Global stressors" affect the entire protein population, for example, temperature. "Local stressors" affect only a partial population at a given instant, for example, stirring. The instrumental error distribution (IED) allows stochasticity to be identified for AR distributions (ARDs) broader than IED. For ARD at the limit of the IED, the behavior is "minimally stochastic" or "operationally deterministic." A stochastic index is defined in terms of the ratio of the standard deviation (SD) of log(AR) data and the SD of IED. Thermal aggregation was operationally deterministic for BSA and mAbX, although significant lot-to-lot variations for BSA were found. ARD from contact-stir-stress was stochastic for BSA and mAb. Despite this, log(AR) decreases logarithmically with rpm. These trends may hold for other global and local stressors.
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Affiliation(s)
- Curtis W Jarand
- Physics Department , Tulane University , New Orleans , Louisiana 70118 , United States
| | - Wayne F Reed
- Physics Department , Tulane University , New Orleans , Louisiana 70118 , United States
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28
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Atlasi RS, Malik R, Corrales CI, Tzeplaeff L, Whitelegge JP, Cashman NR, Bitan G. Investigation of Anti-SOD1 Antibodies Yields New Structural Insight into SOD1 Misfolding and Surprising Behavior of the Antibodies Themselves. ACS Chem Biol 2018; 13:2794-2807. [PMID: 30110532 DOI: 10.1021/acschembio.8b00729] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mutations in Cu/Zn-superoxide dismutase (SOD1) gene are linked to 10-20% of familial amyotrophic lateral sclerosis (fALS) cases. The mutations cause misfolding and self-assembly of SOD1 into toxic oligomers and aggregates, resulting in motor neuron degeneration. The molecular mechanisms underlying SOD1 aggregation and toxicity are unclear. Characterization of misfolded SOD1 is particularly challenging because of its metastable nature. Antibodies against misfolded SOD1 are useful tools for this purpose, provided their specificity and selectivity are well-characterized. Here, we characterized three recently introduced antimisfolded SOD1 antibodies and compared them with two commercial, antimisfolded SOD1 antibodies raised against the fALS-linked variant G93A-SOD1. As controls, we compared the reactivity of these antibodies to two polyclonal anti-SOD1 antibodies expected to be insensitive to misfolding. We asked to what extent the antibodies could distinguish between WT and variant SOD1 and between native and misfolded conformations. WT, G93A-SOD1, or E100K-SOD1 were incubated under aggregation-promoting conditions and monitored using thioflavin-T fluorescence, electron microscopy, and dot blots. WT and G93A-SOD1 also were analyzed using native-PAGE/Western blot. The new antimisfolded SOD1 and the commercial antibody B8H10 showed variable reactivity using dot blots but generally showed maximum reactivity at the time misfolded SOD1 oligomers were expected to be most abundant. In contrast, only B8H10 and the control antibodies were reactive in Western blots. Unexpectedly, the polyclonal antibodies showed strong preference for the misfolded form of G93A-SOD1 in dot blots. Surprisingly, antimisfolded SOD1 antibody C4F6 was specific for the apo form of G93A-SOD1 but insensitive to misfolding. Antibody 10C12 showed preference for early misfolded structures, whereas 3H1 bound preferentially to late structures. These new antibodies allow distinction between putative early- and late-forming prefibrillar SOD1 oligomers.
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Affiliation(s)
| | | | | | | | | | - Neil R. Cashman
- Department of Neurology, University of British Columbia (UBC), Vancouver, British Columbia V6T 2B5, Canada
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29
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Rasouli S, Abdolvahabi A, Croom CM, Plewman DL, Shi Y, Shaw BF. Glycerolipid Headgroups Control Rate and Mechanism of Superoxide Dismutase-1 Aggregation and Accelerate Fibrillization of Slowly Aggregating Amyotrophic Lateral Sclerosis Mutants. ACS Chem Neurosci 2018; 9:1743-1756. [PMID: 29649360 DOI: 10.1021/acschemneuro.8b00086] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Interactions between superoxide dismutase-1 (SOD1) and lipid membranes might be directly involved in the toxicity and intercellular propagation of aggregated SOD1 in amyotrophic lateral sclerosis (ALS), but the chemical details of lipid-SOD1 interactions and their effects on SOD1 aggregation remain unclear. This paper determined the rate and mechanism of nucleation of fibrillar apo-SOD1 catalyzed by liposomal surfaces with identical hydrophobic chains (RCH2(O2C18H33)2), but headgroups of different net charge and hydrophobicity (i.e., R(CH2)N+(CH3)3, RPO4-(CH2)2N+(CH3)3, and RPO4-). Under semiquiescent conditions (within a 96 well microplate, without a gyrating bead), the aggregation of apo-SOD1 into thioflavin-T-positive (ThT(+)) amyloid fibrils did not occur over 120 h in the absence of liposomal surfaces. Anionic liposomes triggered aggregation of apo-SOD1 into ThT(+) amyloid fibrils; cationic liposomes catalyzed fibrillization but at slower rates and across a narrower lipid concentration; zwitterionic liposomes produced nonfibrillar (amorphous) aggregates. The inability of zwitterionic liposomes to catalyze fibrillization and the dependence of fibrillization rate on anionic lipid concentration suggests that membranes catalyze SOD1 fibrillization by a primary nucleation mechanism. Membrane-catalyzed fibrillization was also examined for eight ALS variants of apo-SOD1, including G37R, G93R, D90A, and E100G apo-SOD1 that nucleate slower than or equal to WT SOD1 in lipid-free, nonquiescent amyloid assays. All ALS variants (with one exception) nucleated faster than WT SOD1 in the presence of anionic liposomes, wherein the greatest acceleratory effects were observed among variants with lower net negative surface charge (G37R, G93R, D90A, E100G). The exception was H46R apo-SOD1, which did not form ThT(+) species.
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Affiliation(s)
- Sanaz Rasouli
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76706, United States
- Institute of Biomedical Studies, Baylor University, Waco, Texas 76706, United States
| | - Alireza Abdolvahabi
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Corbin M. Croom
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Devon L. Plewman
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Yunhua Shi
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Bryan F. Shaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76706, United States
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30
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Abu-Hamad S, Kahn J, Leyton-Jaimes MF, Rosenblatt J, Israelson A. Misfolded SOD1 Accumulation and Mitochondrial Association Contribute to the Selective Vulnerability of Motor Neurons in Familial ALS: Correlation to Human Disease. ACS Chem Neurosci 2017; 8:2225-2234. [PMID: 28715630 DOI: 10.1021/acschemneuro.7b00140] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder, with a 10% genetic linkage, of which 20% of these cases may be attributed to mutations in superoxide dismutase (SOD1). Specific mutations in SOD1 have been associated with disease duration, which can be highly variable ranging from a life expectancy of 3 to beyond 10 years. SOD1 neurotoxicity has been attributed to aberrant accumulation of misfolded SOD1, which in its soluble form binds to intracellular organelles disrupting their function or forms insoluble toxic aggregates. To understand whether these biophysical properties of the mutant protein may influence disease onset and duration, we generated 19 point mutations in the SOD1 gene, based on available clinical data of disease onset and progression from patients. By overexpressing these mutants in motor-neuron-like NSC-34 cells, we demonstrate a variability in misfolding capacity between the different mutants with a correlation between the degree of protein misfolding and mutation severity. We also show a clear variation of the different SOD1 mutants to associate with mitochondrial-enriched fractions with a correlation between mutation severity and this association. In summary, these findings reveal a correlation between the accumulation of misfolded SOD1 species and their mitochondrial association with disease duration but not with disease onset, and they have implications for the potential therapeutic role of suppressing the accumulation of misfolded SOD1.
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Affiliation(s)
- Salah Abu-Hamad
- Department
of Physiology and Cell Biology, Faculty of Health Sciences, ‡Department of Industrial
Engineering and Management, and §The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel
| | - Joy Kahn
- Department
of Physiology and Cell Biology, Faculty of Health Sciences, ‡Department of Industrial
Engineering and Management, and §The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel
| | - Marcel F. Leyton-Jaimes
- Department
of Physiology and Cell Biology, Faculty of Health Sciences, ‡Department of Industrial
Engineering and Management, and §The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel
| | - Jonathan Rosenblatt
- Department
of Physiology and Cell Biology, Faculty of Health Sciences, ‡Department of Industrial
Engineering and Management, and §The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel
| | - Adrian Israelson
- Department
of Physiology and Cell Biology, Faculty of Health Sciences, ‡Department of Industrial
Engineering and Management, and §The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, P.O.B. 653, Beer Sheva 84105, Israel
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31
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Rasouli S, Abdolvahabi A, Croom CM, Plewman DL, Shi Y, Ayers JI, Shaw BF. Lysine acylation in superoxide dismutase-1 electrostatically inhibits formation of fibrils with prion-like seeding. J Biol Chem 2017; 292:19366-19380. [PMID: 28974578 DOI: 10.1074/jbc.m117.805283] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/28/2017] [Indexed: 11/06/2022] Open
Abstract
The acylation of lysine residues in superoxide dismutase-1 (SOD1) has been previously shown to decrease its rate of nucleation and elongation into amyloid-like fibrils linked to amyotrophic lateral sclerosis. The chemical mechanism underlying this effect is unclear, i.e. hydrophobic/steric effects versus electrostatic effects. Moreover, the degree to which the acylation might alter the prion-like seeding of SOD1 in vivo has not been addressed. Here, we acylated a fraction of lysine residues in SOD1 with groups of variable hydrophobicity, charge, and conformational entropy. The effect of each acyl group on the rate of SOD1 fibril nucleation and elongation were quantified in vitro with thioflavin-T (ThT) fluorescence, and we performed 594 iterate aggregation assays to obtain statistically significant rates. The effect of the lysine acylation on the prion-like seeding of SOD1 was assayed in spinal cord extracts of transgenic mice expressing a G85R SOD1-yellow fluorescent protein construct. Acyl groups with >2 carboxylic acids diminished self-assembly into ThT-positive fibrils and instead promoted the self-assembly of ThT-negative fibrils and amorphous complexes. The addition of ThT-negative, acylated SOD1 fibrils to organotypic spinal cord failed to produce the SOD1 inclusion pathology that typically results from the addition of ThT-positive SOD1 fibrils. These results suggest that chemically increasing the net negative surface charge of SOD1 via acylation can block the prion-like propagation of oligomeric SOD1 in spinal cord.
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Affiliation(s)
- Sanaz Rasouli
- From the Department of Chemistry and Biochemistry and.,the Institute of Biomedical Studies, Baylor University, Waco, Texas 76706 and
| | | | | | | | - Yunhua Shi
- From the Department of Chemistry and Biochemistry and
| | - Jacob I Ayers
- the Department of Neuroscience, University of Florida, Gainesville, Florida 32611
| | - Bryan F Shaw
- From the Department of Chemistry and Biochemistry and
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32
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Constantinescu P, Brown RA, Wyatt AR, Ranson M, Wilson MR. Amorphous protein aggregates stimulate plasminogen activation, leading to release of cytotoxic fragments that are clients for extracellular chaperones. J Biol Chem 2017; 292:14425-14437. [PMID: 28710283 DOI: 10.1074/jbc.m117.786657] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/09/2017] [Indexed: 01/12/2023] Open
Abstract
The misfolding of proteins and their accumulation in extracellular tissue compartments as insoluble amyloid or amorphous protein aggregates are a hallmark feature of many debilitating protein deposition diseases such as Alzheimer's disease, prion diseases, and type II diabetes. The plasminogen activation system is best known as an extracellular fibrinolytic system but was previously reported to also be capable of degrading amyloid fibrils. Here we show that amorphous protein aggregates interact with tissue-type plasminogen activator and plasminogen, via an exposed lysine-dependent mechanism, to efficiently generate plasmin. The insoluble aggregate-bound plasmin is shielded from inhibition by α2-antiplasmin and degrades amorphous protein aggregates to release smaller, soluble but relatively hydrophobic fragments of protein (plasmin-generated protein fragments (PGPFs)) that are cytotoxic. In vitro, both endothelial and microglial cells bound and internalized PGPFs before trafficking them to lysosomes. Clusterin and α2-macroglobulin bound to PGPFs to significantly ameliorate their toxicity. On the basis of these findings, we hypothesize that, as part of the in vivo extracellular proteostasis system, the plasminogen activation system may work synergistically with extracellular chaperones to safely clear large and otherwise pathological protein aggregates from the body.
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Affiliation(s)
| | | | | | - Marie Ranson
- From the Illawarra Health and Medical Research Institute, Proteostasis and Disease Research Centre, and the School of Biological Sciences, University of Wollongong, Northfields Avenue, Wollongong, New South Wales 2522, Australia
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33
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Abdolvahabi A, Shi Y, Rasouli S, Croom CM, Aliyan A, Martí AA, Shaw BF. Kaplan-Meier Meets Chemical Kinetics: Intrinsic Rate of SOD1 Amyloidogenesis Decreased by Subset of ALS Mutations and Cannot Fully Explain Age of Disease Onset. ACS Chem Neurosci 2017; 8:1378-1389. [PMID: 28290665 DOI: 10.1021/acschemneuro.7b00029] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Over 150 mutations in SOD1 (superoxide dismutase-1) cause amyotrophic lateral sclerosis (ALS), presumably by accelerating SOD1 amyloidogenesis. Like many nucleation processes, SOD1 fibrillization is stochastic (in vitro), which inhibits the determination of aggregation rates (and obscures whether rates correlate with patient phenotypes). Here, we diverged from classical chemical kinetics and used Kaplan-Meier estimators to quantify the probability of apo-SOD1 fibrillization (in vitro) from ∼103 replicate amyloid assays of wild-type (WT) SOD1 and nine ALS variants. The probability of apo-SOD1 fibrillization (expressed as a Hazard ratio) is increased by certain ALS-linked SOD1 mutations but is decreased or remains unchanged by other mutations. Despite this diversity, Hazard ratios of fibrillization correlated linearly with (and for three mutants, approximately equaled) Hazard ratios of patient survival (R2 = 0.67; Pearson's r = 0.82). No correlation exists between Hazard ratios of fibrillization and age of initial onset of ALS (R2 = 0.09). Thus, Hazard ratios of fibrillization might explain rates of disease progression but not onset. Classical kinetic metrics of fibrillization, i.e., mean lag time and propagation rate, did not correlate as strongly with phenotype (and ALS mutations did not uniformly accelerate mean rate of nucleation or propagation). A strong correlation was found, however, between mean ThT fluorescence at lag time and patient survival (R2 = 0.93); oligomers of SOD1 with weaker fluorescence correlated with shorter survival. This study suggests that SOD1 mutations trigger ALS by altering a property of SOD1 or its oligomers other than the intrinsic rate of amyloid nucleation (e.g., oligomer stability; rates of intercellular propagation; affinity for membrane surfaces; and maturation rate).
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Affiliation(s)
- Alireza Abdolvahabi
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Yunhua Shi
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Sanaz Rasouli
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76706, United States
- Institute of Biomedical Studies, Baylor University, Waco, Texas 76706, United States
| | - Corbin M. Croom
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Amir Aliyan
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Angel A. Martí
- Department of Chemistry, Rice University, Houston, Texas 77005, United States
- Department of Bioengineering, Rice University, Houston, Texas 77005, United States
| | - Bryan F. Shaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76706, United States
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34
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Yoshimura Y, Holmberg MA, Kukic P, Andersen CB, Mata-Cabana A, Falsone SF, Vendruscolo M, Nollen EAA, Mulder FAA. MOAG-4 promotes the aggregation of α-synuclein by competing with self-protective electrostatic interactions. J Biol Chem 2017; 292:8269-8278. [PMID: 28336532 DOI: 10.1074/jbc.m116.764886] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 03/01/2017] [Indexed: 11/06/2022] Open
Abstract
Aberrant protein aggregation underlies a variety of age-related neurodegenerative disorders, including Alzheimer's and Parkinson's diseases. Little is known, however, about the molecular mechanisms that modulate the aggregation process in the cellular environment. Recently, MOAG-4/SERF has been identified as a class of evolutionarily conserved proteins that positively regulates aggregate formation. Here, by using nuclear magnetic resonance (NMR) spectroscopy, we examine the mechanism of action of MOAG-4 by characterizing its interaction with α-synuclein (α-Syn). NMR chemical shift perturbations demonstrate that a positively charged segment of MOAG-4 forms a transiently populated α-helix that interacts with the negatively charged C terminus of α-Syn. This process interferes with the intramolecular interactions between the N- and C-terminal regions of α-Syn, resulting in the protein populating less compact forms and aggregating more readily. These results provide a compelling example of the complex competition between molecular and cellular factors that protect against protein aggregation and those that promote it.
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Affiliation(s)
- Yuichi Yoshimura
- Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Mats A Holmberg
- University of Groningen, University Medical Centre Groningen, European Research Institute for the Biology of Aging, 9700 AD Groningen, The Netherlands
| | - Predrag Kukic
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Camilla B Andersen
- Interdisciplinary Nanoscience Center (iNANO) and Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Alejandro Mata-Cabana
- University of Groningen, University Medical Centre Groningen, European Research Institute for the Biology of Aging, 9700 AD Groningen, The Netherlands
| | - S Fabio Falsone
- Institute of Pharmaceutical Sciences, University of Graz, Schubertstr. 1, 8010 Graz, Austria
| | - Michele Vendruscolo
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Ellen A A Nollen
- University of Groningen, University Medical Centre Groningen, European Research Institute for the Biology of Aging, 9700 AD Groningen, The Netherlands
| | - Frans A A Mulder
- Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
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35
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Abdolvahabi A, Shi Y, Rasouli S, Croom CM, Chuprin A, Shaw BF. How Do Gyrating Beads Accelerate Amyloid Fibrillization? Biophys J 2017; 112:250-264. [PMID: 28122213 PMCID: PMC5266089 DOI: 10.1016/j.bpj.2016.12.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/22/2016] [Accepted: 12/05/2016] [Indexed: 01/21/2023] Open
Abstract
The chemical and physical mechanisms by which gyrating beads accelerate amyloid fibrillization in microtiter plate assays are unclear. Identifying these mechanisms will help optimize high-throughput screening assays for molecules and mutations that modulate aggregation and might explain why different research groups report different rates of aggregation for identical proteins. This article investigates how the rate of superoxide dismutase-1 (SOD1) fibrillization is affected by 12 different beads with a wide range of hydrophobicity, mass, stiffness, and topology but identical diameter. All assays were performed on D90A apo-SOD1, which is a stable and wild-type-like variant of SOD1. The most significant and uniform correlation between any material property of each bead and that bead's effect on SOD1 fibrillization rate was with regard to bead mass. A linear correlation existed between bead mass and rate of fibril elongation (R2 = 0.7): heavier beads produced faster rates and shorter fibrils. Nucleation rates (lag time) also correlated with bead mass, but only for non-polymeric beads (i.e., glass, ceramic, metallic). The effect of bead mass on fibrillization correlated (R2 = 0.96) with variations in buoyant forces and contact forces (between bead and microplate well), and was not an artifact of residual momentum during intermittent gyration. Hydrophobic effects were observed, but only for polymeric beads: lag times correlated negatively with contact angle of water and degree of protein adhesion (surface adhesion and hydrophobic effects were negligible for non-polymeric beads). These results demonstrate that contact forces (alone) explain kinetic variation among non-polymeric beads, whereas surface hydrophobicity and contact forces explain kinetic variation among polymeric beads. This study also establishes conditions for high-throughput amyloid assays of SOD1 that enable the control over fibril morphologies and produce eightfold faster lag times and fourfold less stochasticity than in previous studies.
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Affiliation(s)
| | - Yunhua Shi
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas
| | - Sanaz Rasouli
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas; Institute of Biomedical Studies, Baylor University, Waco, Texas
| | - Corbin M Croom
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas
| | - Aleksandra Chuprin
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas
| | - Bryan F Shaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas.
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McAlary L, Aquilina JA, Yerbury JJ. Susceptibility of Mutant SOD1 to Form a Destabilized Monomer Predicts Cellular Aggregation and Toxicity but Not In vitro Aggregation Propensity. Front Neurosci 2016; 10:499. [PMID: 27867347 PMCID: PMC5095133 DOI: 10.3389/fnins.2016.00499] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 10/20/2016] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the rapid and progressive degeneration of upper and lower motor neurons in the spinal cord, brain stem and motor cortex. The first gene linked to ALS was the gene encoding the free radical scavenging enzyme superoxide dismutase-1 (SOD1) that currently has over 180, mostly missense, ALS-associated mutations identified. SOD1-associated fALS patients show remarkably broad mean survival times (<1 year to ~17 years death post-diagnosis) that are mutation dependent. A hallmark of SOD1-associated ALS is the deposition of SOD1 into large insoluble aggregates in motor neurons. This is thought to be a consequence of mutation induced structural destabilization and/or oxidative damage leading to the misfolding and aggregation of SOD1 into a neurotoxic species. Here we aim to understand the relationship between SOD1 variant toxicity, structural stability, and aggregation propensity using a combination of cell culture and purified protein assays. Cell based assays indicated that aggregation of SOD1 variants correlate closely to cellular toxicity. However, the relationship between cellular toxicity and disease severity was less clear. We next utilized mass spectrometry to interrogate the structural consequences of metal loss and disulfide reduction on fALS-associated SOD1 variant structure. All variants showed evidence of unfolded, intermediate, and compact conformations, with SOD1G37R, SOD1G93A and SOD1V148G having the greatest abundance of intermediate and unfolded SOD1. SOD1G37R was an informative outlier as it had a high propensity to unfold and form oligomeric aggregates, but it did not aggregate to the same extent as SOD1G93A and SOD1V148G in in vitro aggregation assays. Furthermore, seeding the aggregation of DTT/EDTA-treated SOD1G37R with preformed SOD1G93A fibrils elicited minimal aggregation response, suggesting that the arginine substitution at position-37 blocks the templating of SOD1 onto preformed fibrils. We propose that this difference may be explained by multiple strains of SOD1 aggregate and this may also help explain the slow disease progression observed in patients with SOD1G37R.
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Affiliation(s)
- Luke McAlary
- Lab 210, Illawarra Health and Medical Research InstituteWollongong, NSW, Australia; Science Medicine and Health Faculty, School of Biological Sciences, University of WollongongWollongong, NSW, Australia
| | - J Andrew Aquilina
- Science Medicine and Health Faculty, School of Biological Sciences, University of Wollongong Wollongong, NSW, Australia
| | - Justin J Yerbury
- Lab 210, Illawarra Health and Medical Research InstituteWollongong, NSW, Australia; Science Medicine and Health Faculty, School of Biological Sciences, University of WollongongWollongong, NSW, Australia
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