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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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Helmold BR, Pauss KE, Ozdinler PH. TDP-43 protein interactome informs about perturbed canonical pathways and may help develop personalized medicine approaches for patients with TDP-43 pathology. Drug Discov Today 2023; 28:103769. [PMID: 37714405 PMCID: PMC10872580 DOI: 10.1016/j.drudis.2023.103769] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 08/22/2023] [Accepted: 09/08/2023] [Indexed: 09/17/2023]
Abstract
Transactive response DNA binding protein of 43 kDa (TDP-43) pathology is a common proteinopathy observed among a broad spectrum of patients with neurodegenerative disease, regardless of the mutation. This suggests that protein-protein interactions of TDP-43 with other proteins may in part be responsible for the pathology. To gain better insights, we investigated TDP-43-binding proteins in each domain and correlated these interactions with canonical pathways. These investigations revealed key cellular events that are involved and are important at each domain and suggested previously identified compounds to modulate key aspects of these canonical pathways. Our approach proposes that personalized medicine approaches, which focus on perturbed cellular mechanisms would be feasible in the near future.
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Affiliation(s)
- Benjamin R Helmold
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave, Chicago, IL, 60611, USA
| | - Kate E Pauss
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave, Chicago, IL, 60611, USA
| | - P Hande Ozdinler
- Department of Neurology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave, Chicago, IL, 60611, USA; Center for Molecular Innovation and Drug Discovery, Center for Developmental Therapeutics, Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60611, USA; Mesulam Center for Cognitive Neurology and Alzheimer's Disease, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Feinberg School of Medicine, Les Turner ALS Center at Northwestern University, Chicago, IL 60611, USA.
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3
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Furukawa Y. A pathological link between dysregulated copper binding in Cu/Zn-superoxide dismutase and amyotrophic lateral sclerosis. J Clin Biochem Nutr 2022; 71:73-77. [PMID: 36213785 PMCID: PMC9519421 DOI: 10.3164/jcbn.22-42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/17/2022] [Indexed: 11/22/2022] Open
Abstract
Mutations in the gene coding Cu/Zn-superoxide dismutase (SOD1) are linked to a familial form of amyotrophic lateral sclerosis (ALS), and its pathological hallmark includes abnormal accumulation of mutant SOD1 proteins in spinal motorneurons. Mutant SOD1 proteins are considered to be susceptible to misfolding, resulting in the accumulation as oligomers/aggregates. While it remains obscure how and why SOD1 becomes misfolded under pathological conditions in vivo, the failure to bind a copper and zinc ion in SOD1 in vitro leads to the significant destabilization of its natively folded structure. Therefore, genetic and pharmacological attempts to promote the metal binding in mutant SOD1 could serve as an effective treatment of ALS. Here, I briefly review the copper and zinc binding process of SOD1 in vivo and discuss a copper chaperone for SOD1 as a potential target for developing ALS therapeutics.
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Molecular and pharmacological chaperones for SOD1. Biochem Soc Trans 2021; 48:1795-1806. [PMID: 32794552 PMCID: PMC7458393 DOI: 10.1042/bst20200318] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/16/2020] [Accepted: 07/17/2020] [Indexed: 12/25/2022]
Abstract
The efficacy of superoxide dismutase-1 (SOD1) folding impacts neuronal loss in motor system neurodegenerative diseases. Mutations can prevent SOD1 post-translational processing leading to misfolding and cytoplasmic aggregation in familial amyotrophic lateral sclerosis (ALS). Evidence of immature, wild-type SOD1 misfolding has also been observed in sporadic ALS, non-SOD1 familial ALS and Parkinson's disease. The copper chaperone for SOD1 (hCCS) is a dedicated and specific chaperone that assists SOD1 folding and maturation to produce the active enzyme. Misfolded or misfolding prone SOD1 also interacts with heat shock proteins and macrophage migration inhibitory factor to aid folding, refolding or degradation. Recognition of specific SOD1 structures by the molecular chaperone network and timely dissociation of SOD1-chaperone complexes are, therefore, important steps in SOD1 processing. Harnessing these interactions for therapeutic benefit is actively pursued as is the modulation of SOD1 behaviour with pharmacological and peptide chaperones. This review highlights the structural and mechanistic aspects of a selection of SOD1-chaperone interactions together with their impact on disease models.
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ATP7A-Regulated Enzyme Metalation and Trafficking in the Menkes Disease Puzzle. Biomedicines 2021; 9:biomedicines9040391. [PMID: 33917579 PMCID: PMC8067471 DOI: 10.3390/biomedicines9040391] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/01/2021] [Accepted: 04/02/2021] [Indexed: 12/12/2022] Open
Abstract
Copper is vital for numerous cellular functions affecting all tissues and organ systems in the body. The copper pump, ATP7A is critical for whole-body, cellular, and subcellular copper homeostasis, and dysfunction due to genetic defects results in Menkes disease. ATP7A dysfunction leads to copper deficiency in nervous tissue, liver, and blood but accumulation in other tissues. Site-specific cellular deficiencies of copper lead to loss of function of copper-dependent enzymes in all tissues, and the range of Menkes disease pathologies observed can now be explained in full by lack of specific copper enzymes. New pathways involving copper activated lysosomal and steroid sulfatases link patient symptoms usually related to other inborn errors of metabolism to Menkes disease. Additionally, new roles for lysyl oxidase in activation of molecules necessary for the innate immune system, and novel adapter molecules that play roles in ERGIC trafficking of brain receptors and other proteins, are emerging. We here summarize the current knowledge of the roles of copper enzyme function in Menkes disease, with a focus on ATP7A-mediated enzyme metalation in the secretory pathway. By establishing mechanistic relationships between copper-dependent cellular processes and Menkes disease symptoms in patients will not only increase understanding of copper biology but will also allow for the identification of an expanding range of copper-dependent enzymes and pathways. This will raise awareness of rare patient symptoms, and thus aid in early diagnosis of Menkes disease patients.
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Azoulay-Ginsburg S, Di Salvio M, Weitman M, Afri M, Ribeiro S, Ebbinghaus S, Cestra G, Gruzman A. Chemical chaperones targeted to the endoplasmic reticulum (ER) and lysosome prevented neurodegeneration in a C9orf72 repeat expansion drosophila amyotrophic lateral sclerosis (ALS) model. Pharmacol Rep 2021; 73:536-550. [PMID: 33661518 DOI: 10.1007/s43440-021-00226-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/28/2021] [Accepted: 02/01/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND ALS is an incurable neuromuscular degenerative disorder. A familiar form of the disease (fALS) is related to point mutations. The most common one is an expansion of a noncoding GGGGCC hexanucleotide repeat of the C9orf72 gene on chromosome 9p21. An abnormal translation of the C9orf72 gene generates dipeptide repeat proteins that aggregate in the brain. One of the classical approaches for developing treatment against protein aggregation-related diseases is to use chemical chaperones (CSs). In this work, we describe the development of novel 4-phenylbutyric acid (4-PBA) lysosome/ER-targeted derivatives. We assumed that 4-PBA targeting to specific organelles, where protein degradation takes place, might reduce the 4-PBA effective concentration. METHODS Organic chemistry synthetic methods and solid-phase peptide synthesis (SPPS) were used for preparing the 4-PBA derivatives. The obtained compounds were evaluated in an ALS Drosophila model that expressed C9orf72 repeat expansion, causing eye degeneration. Targeting to lysosome was validated by the 19F-nuclear magnetic resonance (NMR) technique. RESULTS Several synthesized compounds exhibited a significant biological effect by ameliorating the eye degeneration. They blocked the neurodegeneration of fly retina at different efficacy levels. The most active CS was compound 9, which is a peptide derivative and was targeted to ER. Another active compound targeted to lysosome was compound 4. CONCLUSIONS Novel CSs were more effective than 4-PBA; therefore, they might be used as a new class of drug candidates to treat ALS and other protein misfolding disorders.
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Affiliation(s)
| | - Michela Di Salvio
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185, Rome, Italy.,Institute of Molecular Biology and Pathology, National Research Council, Sapienza University of Rome, 00185, Rome, Italy
| | | | - Michal Afri
- Bar-Ilan University, 5290002, Ramat-Gan, Israel
| | - Sara Ribeiro
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, 38106, Braunschweig, Germany
| | - Simon Ebbinghaus
- Institute of Physical and Theoretical Chemistry, TU Braunschweig, 38106, Braunschweig, Germany
| | - Gianluca Cestra
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185, Rome, Italy. .,Institute of Molecular Biology and Pathology, National Research Council, Sapienza University of Rome, 00185, Rome, Italy.
| | - Arie Gruzman
- Bar-Ilan University, 5290002, Ramat-Gan, Israel.
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7
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Amporndanai K, Rogers M, Watanabe S, Yamanaka K, O'Neill PM, Hasnain SS. Novel Selenium-based compounds with therapeutic potential for SOD1-linked amyotrophic lateral sclerosis. EBioMedicine 2020; 59:102980. [PMID: 32862101 PMCID: PMC7456458 DOI: 10.1016/j.ebiom.2020.102980] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 12/13/2022] Open
Abstract
Background Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease as well as Lou Gehrig's disease, is a progressive neurological disorder selectively affecting motor neurons with no currently known cure. Around 20% of the familial ALS cases arise from dominant mutations in the sod1 gene encoding superoxide dismutase1 (SOD1) enzyme. Aggregation of mutant SOD1 in familial cases and of wild-type SOD1 in at least some sporadic ALS cases is one of the known causes of the disease. Riluzole, approved in 1995 and edaravone in 2017 remain the only drugs with limited therapeutic benefits. Methods We have utilised the ebselen template to develop novel compounds that redeem stability of mutant SOD1 dimer and prevent aggregation. Binding modes of compounds have been visualised by crystallography. In vitro neuroprotection and toxicity of lead compounds have been performed in mouse neuronal cells and disease onset delay of ebselen has been demonstrated in transgenic ALS mice model. Finding We have developed a number of ebselen-based compounds with improvements in A4V SOD1 stabilisation and in vitro therapeutic effects with significantly better potency than edaravone. Structure-activity relationship of hits has been guided by high resolution structures of ligand-bound A4V SOD1. We also show clear disease onset delay of ebselen in transgenic ALS mice model holding encouraging promise for potential therapeutic compounds. Interpretation Our finding established the new generation of organo-selenium compounds with better in vitro neuroprotective activity than edaravone. The potential of this class of compounds may offer an alternative therapeutic agent for ALS treatment. The ability of these compounds to target cysteine 111 in SOD may have wider therapeutic applications targeting cysteines of enzymes involved in pathogenic and viral diseases including main protease of SARS-Cov-2 (COVID-19). Funding Project funding was supported by the 10.13039/100000971ALS Association grant (WA1128) and Fostering Joint International Research (19KK0214) from the 10.13039/100009950Ministry of Education, Culture, Sports, Science and Technology (10.13039/501100001700MEXT), Japan.
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Affiliation(s)
- Kangsa Amporndanai
- Molecular Biophysics Group, Department of Biochemistry and System Biology, Institute of System, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Michael Rogers
- Department of Chemistry, Faculty of Science and Engineering, University of Liverpool, Liverpool, L69 7ZD, United Kingdom
| | - Seiji Watanabe
- Department of Neuroscience & Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan; Department of Neuroscience and Pathobiology, Nagoya University Graduate School of Medicine, Aichi, 466-8550, Japan
| | - Koji Yamanaka
- Department of Neuroscience & Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan; Department of Neuroscience and Pathobiology, Nagoya University Graduate School of Medicine, Aichi, 466-8550, Japan
| | - Paul M O'Neill
- Department of Chemistry, Faculty of Science and Engineering, University of Liverpool, Liverpool, L69 7ZD, United Kingdom
| | - S Samar Hasnain
- Molecular Biophysics Group, Department of Biochemistry and System Biology, Institute of System, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
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8
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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: 65] [Impact Index Per Article: 16.3] [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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9
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Ge Y, Wang L, Li D, Zhao C, Li J, Liu T. Exploring the Extended Biological Functions of the Human Copper Chaperone of Superoxide Dismutase 1. Protein J 2020; 38:463-471. [PMID: 31140034 DOI: 10.1007/s10930-019-09824-9] [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] [Indexed: 12/27/2022]
Abstract
The human copper chaperone of SOD1 (designated as CCS) was discovered more than two decades ago. It is an important copper binding protein and a homolog of Saccharomyces cerevisiae LYS7. To date, no studies have systematically or specifically elaborated on the functional development of CCS. This review summarizes the essential information about CCS, such as its localization, 3D structure, and copper binding ability. An emphasis is placed on its interacting protein partners and its biological functions in vivo and in vitro. Three-dimensional structural analysis revealed that CCS is composed of three domains. Its primary molecular function is the delivery of copper to SOD1 and activation of SOD1. It has also been reported to bind to XIAP, Mia40, and X11α, and other proteins. Through these protein partners, CCS is implicated in several vital biological processes in vivo, such as copper homeostasis, apoptosis, angiogenesis and oxidative stress. This review is anticipated to assist scientists in systematically understanding the latest research developments of CCS for facilitating the development of new therapeutics targeting CCS in the future.
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Affiliation(s)
- Yan Ge
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168 Huaguan Road, Chenghua District, Chengdu, 610052, China.,International Phage Drug Research Center, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China
| | - Lu Wang
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168 Huaguan Road, Chenghua District, Chengdu, 610052, China. .,International Phage Drug Research Center, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China.
| | - Duanhua Li
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168 Huaguan Road, Chenghua District, Chengdu, 610052, China.,International Phage Drug Research Center, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China
| | - Chen Zhao
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168 Huaguan Road, Chenghua District, Chengdu, 610052, China.,International Phage Drug Research Center, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China
| | - Jinjun Li
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168 Huaguan Road, Chenghua District, Chengdu, 610052, China.,International Phage Drug Research Center, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China
| | - Tao Liu
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, Chengdu University, No. 168 Huaguan Road, Chenghua District, Chengdu, 610052, China.,International Phage Drug Research Center, Sichuan Industrial Institute of Antibiotics, Chengdu University, Chengdu, China
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10
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Chantadul V, Wright GSA, Amporndanai K, Shahid M, Antonyuk SV, Washbourn G, Rogers M, Roberts N, Pye M, O'Neill PM, Hasnain SS. Ebselen as template for stabilization of A4V mutant dimer for motor neuron disease therapy. Commun Biol 2020; 3:97. [PMID: 32139772 PMCID: PMC7058017 DOI: 10.1038/s42003-020-0826-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/13/2020] [Indexed: 11/09/2022] Open
Abstract
Mutations to the gene encoding superoxide dismutase-1 (SOD1) were the first genetic elements discovered that cause motor neuron disease (MND). These mutations result in compromised SOD1 dimer stability, with one of the severest and most common mutations Ala4Val (A4V) displaying a propensity to monomerise and aggregate leading to neuronal death. We show that the clinically used ebselen and related analogues promote thermal stability of A4V SOD1 when binding to Cys111 only. We have developed a A4V SOD1 differential scanning fluorescence-based assay on a C6S mutation background that is effective in assessing suitability of compounds. Crystallographic data show that the selenium atom of these compounds binds covalently to A4V SOD1 at Cys111 at the dimer interface, resulting in stabilisation. This together with chemical amenability for hit expansion of ebselen and its on-target SOD1 pharmacological chaperone activity holds remarkable promise for structure-based therapeutics for MND using ebselen as a template.
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Affiliation(s)
- Varunya Chantadul
- Faculty of Health and Life Sciences, Molecular Biophysics Group, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
- Faculty of Dentistry, Department of Anatomy, Mahidol University, Bangkok, 10400, Thailand
| | - Gareth S A Wright
- Faculty of Health and Life Sciences, Molecular Biophysics Group, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Kangsa Amporndanai
- Faculty of Health and Life Sciences, Molecular Biophysics Group, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Munazza Shahid
- Department of Chemistry and Chemical Engineering, Lahore University of Management Sciences, Punjab, 54792, Pakistan
| | - Svetlana V Antonyuk
- Faculty of Health and Life Sciences, Molecular Biophysics Group, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Gina Washbourn
- Faculty of Science and Engineering, Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Michael Rogers
- Faculty of Science and Engineering, Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Natalie Roberts
- Faculty of Science and Engineering, Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Matthew Pye
- Faculty of Science and Engineering, Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - Paul M O'Neill
- Faculty of Science and Engineering, Department of Chemistry, University of Liverpool, Liverpool, L69 7ZD, UK
| | - S Samar Hasnain
- Faculty of Health and Life Sciences, Molecular Biophysics Group, Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK.
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11
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Semmler S, Gagné M, Garg P, Pickles SR, Baudouin C, Hamon-Keromen E, Destroismaisons L, Khalfallah Y, Chaineau M, Caron E, Bayne AN, Trempe JF, Cashman NR, Star AT, Haqqani AS, Durcan TM, Meiering EM, Robertson J, Grandvaux N, Plotkin SS, McBride HM, Vande Velde C. TNF receptor-associated factor 6 interacts with ALS-linked misfolded superoxide dismutase 1 and promotes aggregation. J Biol Chem 2020; 295:3808-3825. [PMID: 32029478 DOI: 10.1074/jbc.ra119.011215] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/17/2020] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease, characterized by the selective loss of motor neurons leading to paralysis. Mutations in the gene encoding superoxide dismutase 1 (SOD1) are the second most common cause of familial ALS, and considerable evidence suggests that these mutations result in an increase in toxicity due to protein misfolding. We previously demonstrated in the SOD1G93A rat model that misfolded SOD1 exists as distinct conformers and forms deposits on mitochondrial subpopulations. Here, using SOD1G93A rats and conformation-restricted antibodies specific for misfolded SOD1 (B8H10 and AMF7-63), we identified the interactomes of the mitochondrial pools of misfolded SOD1. This strategy identified binding proteins that uniquely interacted with either AMF7-63 or B8H10-reactive SOD1 conformers as well as a high proportion of interactors common to both conformers. Of this latter set, we identified the E3 ubiquitin ligase TNF receptor-associated factor 6 (TRAF6) as a SOD1 interactor, and we determined that exposure of the SOD1 functional loops facilitates this interaction. Of note, this conformational change was not universally fulfilled by all SOD1 variants and differentiated TRAF6 interacting from TRAF6 noninteracting SOD1 variants. Functionally, TRAF6 stimulated polyubiquitination and aggregation of the interacting SOD1 variants. TRAF6 E3 ubiquitin ligase activity was required for the former but was dispensable for the latter, indicating that TRAF6-mediated polyubiquitination and aggregation of the SOD1 variants are independent events. We propose that the interaction between misfolded SOD1 and TRAF6 may be relevant to the etiology of ALS.
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Affiliation(s)
- Sabrina Semmler
- Department of Neurology and Neurosurgery, McGill University, Montréal, Quebec H3A 2B4, Canada.,Centre de Recherche du Centre Hospitalier de Université de Montréal, Montréal, Quebec H2X 0A9, Canada
| | - Myriam Gagné
- Centre de Recherche du Centre Hospitalier de Université de Montréal, Montréal, Quebec H2X 0A9, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Quebec H3T 1J4, Canada
| | - Pranav Garg
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Sarah R Pickles
- Centre de Recherche du Centre Hospitalier de Université de Montréal, Montréal, Quebec H2X 0A9, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Quebec H3T 1J4, Canada
| | - Charlotte Baudouin
- Centre de Recherche du Centre Hospitalier de Université de Montréal, Montréal, Quebec H2X 0A9, Canada.,Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Emeline Hamon-Keromen
- Centre de Recherche du Centre Hospitalier de Université de Montréal, Montréal, Quebec H2X 0A9, Canada.,Université Pierre et Marie Curie, 75005 Paris, France
| | - Laurie Destroismaisons
- Centre de Recherche du Centre Hospitalier de Université de Montréal, Montréal, Quebec H2X 0A9, Canada
| | - Yousra Khalfallah
- Centre de Recherche du Centre Hospitalier de Université de Montréal, Montréal, Quebec H2X 0A9, Canada.,Department of Neurosciences, Université de Montréal, Montréal, Quebec H3T 1J4, Canada
| | - Mathilde Chaineau
- Department of Neurology and Neurosurgery, McGill University, Montréal, Quebec H3A 2B4, Canada.,Montreal Neurological Institute, McGill University, Montréal, Quebec H3A 2B4, Canada
| | - Elise Caron
- Centre de Recherche du Centre Hospitalier de Université de Montréal, Montréal, Quebec H2X 0A9, Canada
| | - Andrew N Bayne
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec H3A 2B4, Canada
| | - Jean-François Trempe
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec H3A 2B4, Canada
| | - Neil R Cashman
- Department of Medicine (Neurology), University of British Columbia and Vancouver Coastal Health Research Institute, Brain Research Centre, Vancouver, British Columbia V6T 2B5, Canada
| | - Alexandra T Star
- Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada
| | - Arsalan S Haqqani
- Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada
| | - Thomas M Durcan
- Department of Neurology and Neurosurgery, McGill University, Montréal, Quebec H3A 2B4, Canada.,Montreal Neurological Institute, McGill University, Montréal, Quebec H3A 2B4, Canada
| | - Elizabeth M Meiering
- Department of Chemistry, Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Janice Robertson
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario M5T 0S8, Canada
| | - Nathalie Grandvaux
- Centre de Recherche du Centre Hospitalier de Université de Montréal, Montréal, Quebec H2X 0A9, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Quebec H3T 1J4, Canada
| | - Steven S Plotkin
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Heidi M McBride
- Department of Neurology and Neurosurgery, McGill University, Montréal, Quebec H3A 2B4, Canada.,Montreal Neurological Institute, McGill University, Montréal, Quebec H3A 2B4, Canada
| | - Christine Vande Velde
- Centre de Recherche du Centre Hospitalier de Université de Montréal, Montréal, Quebec H2X 0A9, Canada .,Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Quebec H3T 1J4, Canada.,Department of Neurosciences, Université de Montréal, Montréal, Quebec H3T 1J4, Canada
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12
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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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13
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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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14
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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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15
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Skopp A, Boyd SD, Ullrich MS, Liu L, Winkler DD. Copper-zinc superoxide dismutase (Sod1) activation terminates interaction between its copper chaperone (Ccs) and the cytosolic metal-binding domain of the copper importer Ctr1. Biometals 2019; 32:695-705. [PMID: 31292775 PMCID: PMC6647829 DOI: 10.1007/s10534-019-00206-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/03/2019] [Indexed: 11/17/2022]
Abstract
Copper-zinc superoxide dismutase (Sod1) is a critical antioxidant enzyme that rids the cell of reactive oxygen through the redox cycling of a catalytic copper ion provided by its copper chaperone (Ccs). Ccs must first acquire this copper ion, directly or indirectly, from the influx copper transporter, Ctr1. The three proteins of this transport pathway ensure careful trafficking of copper ions from cell entry to target delivery, but the intricacies remain undefined. Biochemical examination of each step in the pathway determined that the activation of the target (Sod1) regulates the Ccs·Ctr1 interaction. Ccs stably interacts with the cytosolic C-terminal tail of Ctr1 (Ctr1c) in a copper-dependent manner. This interaction becomes tripartite upon the addition of an engineered immature form of Sod1 creating a stable Cu(I)-Ctr1c·Ccs·Sod1 heterotrimer in solution. This heterotrimer can also be made by the addition of a preformed Sod1·Ccs heterodimer to Cu(I)-Ctr1c, suggestive of multiple routes to the same destination. Only complete Sod1 activation (i.e. active site copper delivery and intra-subunit disulfide bond formation) breaks the Sod1·Ccs·Ctr1c complex. The results provide a new and extended view of the Sod1 activation pathway(s) originating at cellular copper import.
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Affiliation(s)
- Amélie Skopp
- Department of Biological Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Stefanie D Boyd
- Department of Biological Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Morgan S Ullrich
- Department of Biological Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Li Liu
- Department of Biological Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Duane D Winkler
- Department of Biological Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA.
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16
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Switching on Endogenous Metal Binding Proteins in Parkinson's Disease. Cells 2019; 8:cells8020179. [PMID: 30791479 PMCID: PMC6406413 DOI: 10.3390/cells8020179] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 01/26/2019] [Accepted: 02/05/2019] [Indexed: 12/28/2022] Open
Abstract
The formation of cytotoxic intracellular protein aggregates is a pathological signature of multiple neurodegenerative diseases. The principle aggregating protein in Parkinson’s disease (PD) and atypical Parkinson’s diseases is α-synuclein (α-syn), which occurs in neural cytoplasmic inclusions. Several factors have been found to trigger α-syn aggregation, including raised calcium, iron, and copper. Transcriptional inducers have been explored to upregulate expression of endogenous metal-binding proteins as a potential neuroprotective strategy. The vitamin-D analogue, calcipotriol, induced increased expression of the neuronal vitamin D-dependent calcium-binding protein, calbindin-D28k, and this significantly decreased the occurrence of α-syn aggregates in cells with transiently raised intracellular free Ca, thereby increasing viability. More recently, the induction of endogenous expression of the Zn and Cu binding protein, metallothionein, by the glucocorticoid analogue, dexamethasone, gave a specific reduction in Cu-dependent α-syn aggregates. Fe accumulation has long been associated with PD. Intracellularly, Fe is regulated by interactions between the Fe storage protein ferritin and Fe transporters, such as poly(C)-binding protein 1. Analysis of the transcriptional regulation of Fe binding proteins may reveal potential inducers that could modulate Fe homoeostasis in disease. The current review highlights recent studies that suggest that transcriptional inducers may have potential as novel mechanism-based drugs against metal overload in PD.
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17
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Sala FA, Wright GSA, Antonyuk SV, Garratt RC, Hasnain SS. Molecular recognition and maturation of SOD1 by its evolutionarily destabilised cognate chaperone hCCS. PLoS Biol 2019; 17:e3000141. [PMID: 30735496 PMCID: PMC6383938 DOI: 10.1371/journal.pbio.3000141] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 02/21/2019] [Accepted: 01/22/2019] [Indexed: 11/19/2022] Open
Abstract
Superoxide dismutase-1 (SOD1) maturation comprises a string of posttranslational modifications which transform the nascent peptide into a stable and active enzyme. The successive folding, metal ion binding, and disulphide acquisition steps in this pathway can be catalysed through a direct interaction with the copper chaperone for SOD1 (CCS). This process confers enzymatic activity and reduces access to noncanonical, aggregation-prone states. Here, we present the functional mechanisms of human copper chaperone for SOD1 (hCCS)-catalysed SOD1 activation based on crystal structures of reaction precursors, intermediates, and products. Molecular recognition of immature SOD1 by hCCS is driven by several interface interactions, which provide an extended surface upon which SOD1 folds. Induced-fit complexation is reliant on the structural plasticity of the immature SOD1 disulphide sub-loop, a characteristic which contributes to misfolding and aggregation in neurodegenerative disease. Complexation specifically stabilises the SOD1 disulphide sub-loop, priming it and the active site for copper transfer, while delaying disulphide formation and complex dissociation. Critically, a single destabilising amino acid substitution within the hCCS interface reduces hCCS homodimer affinity, creating a pool of hCCS available to interact with immature SOD1. hCCS substrate specificity, segregation between solvent and biological membranes, and interaction transience are direct results of this substitution. In this way, hCCS-catalysed SOD1 maturation is finessed to minimise copper wastage and reduce production of potentially toxic SOD1 species.
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Affiliation(s)
- Fernanda A. Sala
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, Brazil
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - Gareth S. A. Wright
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Svetlana V. Antonyuk
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Richard C. Garratt
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - S. Samar Hasnain
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
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18
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Polykretis P, Cencetti F, Donati C, Luchinat E, Banci L. Cadmium effects on superoxide dismutase 1 in human cells revealed by NMR. Redox Biol 2019; 21:101102. [PMID: 30654299 PMCID: PMC6348768 DOI: 10.1016/j.redox.2019.101102] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/29/2018] [Accepted: 01/07/2019] [Indexed: 11/24/2022] Open
Abstract
Cadmium is a toxic pollutant that in recent decades has become more widespread in the environment due to anthropogenic activities, significantly increasing the risk of exposure. Concurrently, a continually growing body of research has begun to enumerate the harmful effects that this heavy metal has on human health. Consequently, additional research is required to better understand the mechanism and effects of cadmium at the molecular level. The main mechanism of cadmium toxicity is based on the indirect induction of severe oxidative stress, through several processes that unbalance the anti-oxidant cellular defence system, including the displacement of metals such as zinc from its native binding sites. Such mechanism was thought to alter the in vivo enzymatic activity of SOD1, one of the main antioxidant proteins of many tissues, including the central nervous system. SOD1 misfolding and aggregation is correlated with cytotoxicity in neurodegenerative diseases such as amyotrophic lateral sclerosis. We assessed the effect of cadmium on SOD1 folding and maturation pathway directly in human cells through in-cell NMR. Cadmium does not directly bind intracellular SOD1, instead causes the formation of its intramolecular disulfide bond in the zinc-bound form. Metallothionein overexpression is strongly induced by cadmium, reaching NMR-detectable levels. The intracellular availability of zinc modulates both SOD1 oxidation and metallothionein overexpression, strengthening the notion that zinc-loaded metallothioneins help maintaining the redox balance under cadmium-induced acute stress. Cadmium does not bind to superoxide dismutase 1 (SOD1) in human cells. In defect of zinc, cadmium causes the premature oxidation of SOD1. Cadmium induces the overexpression of metallothioneins to levels detectable by NMR. Zinc modulates metallothionein expression and attenuates SOD1 oxidation.
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Affiliation(s)
- Panagis Polykretis
- Magnetic Resonance Center - CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Francesca Cencetti
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Viale Morgagni 50, 50134 Florence, Italy
| | - Chiara Donati
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Viale Morgagni 50, 50134 Florence, Italy
| | - Enrico Luchinat
- Magnetic Resonance Center - CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy; Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Viale Morgagni 50, 50134 Florence, Italy.
| | - Lucia Banci
- Magnetic Resonance Center - CERM, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy; Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy.
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19
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Boyd SD, Calvo JS, Liu L, Ullrich MS, Skopp A, Meloni G, Winkler DD. The yeast copper chaperone for copper-zinc superoxide dismutase (CCS1) is a multifunctional chaperone promoting all levels of SOD1 maturation. J Biol Chem 2018; 294:1956-1966. [PMID: 30530491 DOI: 10.1074/jbc.ra118.005283] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 11/30/2018] [Indexed: 11/06/2022] Open
Abstract
Copper (Cu) is essential for the survival of aerobic organisms through its interaction with molecular oxygen (O2). However, Cu's chemical properties also make it toxic, requiring specific cellular mechanisms for Cu uptake and handling, mediated by Cu chaperones. CCS1, the budding yeast (S. cerevisiae) Cu chaperone for Cu-zinc (Zn) superoxide dismutase (SOD1) activates by directly promoting both Cu delivery and disulfide formation in SOD1. The complete mechanistic details of this transaction along with recently proposed molecular chaperone-like functions for CCS1 remain undefined. Here, we present combined structural, spectroscopic, kinetic, and thermodynamic data that suggest a multifunctional chaperoning role(s) for CCS1 during SOD1 activation. We observed that CCS1 preferentially binds a completely immature form of SOD1 and that the SOD1·CCS1 interaction promotes high-affinity Zn(II) binding in SOD1. Conserved aromatic residues within the CCS1 C-terminal domain are integral in these processes. Previously, we have shown that CCS1 delivers Cu(I) to an entry site at the SOD1·CCS1 interface upon binding. We show here that Cu(I) is transferred from CCS1 to the entry site and then to the SOD1 active site by a thermodynamically driven affinity gradient. We also noted that efficient transfer from the entry site to the active site is entirely dependent upon the oxidation of the conserved intrasubunit disulfide bond in SOD1. Our results herein provide a solid foundation for proposing a complete molecular mechanism for CCS1 activity and reclassification as a first-of-its-kind "dual chaperone."
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Affiliation(s)
| | - Jenifer S Calvo
- Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080
| | - Li Liu
- From the Departments of Biological Sciences and
| | | | | | - Gabriele Meloni
- Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080
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20
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Boyd SD, Liu L, Bulla L, Winkler DD. Quantifying the Interaction between Copper-Zinc Superoxide Dismutase (Sod1) and its Copper Chaperone (Ccs1). ACTA ACUST UNITED AC 2018; 11. [PMID: 29950795 PMCID: PMC6018003 DOI: 10.4172/jpb.1000473] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Immature copper-zinc superoxide dismutase (Sod1) is activated by its copper chaperone (Ccs1). Ccs1 delivers a single copper ion and catalyzes oxidation of an intra-subunit disulfide bond within each Sod1 monomer through a mechanistically ambiguous process. Here, we use residue specific fluorescent labeling of immature Sod1 to quantitate the thermodynamics of the Sod1•Ccs1 interaction while determining a more complete view of Ccs1 function. Ccs1 preferentially binds a completely immature form of Sod1 that is metal deficient and disulfide reduced (E, E-Sod1SH). However, binding induces structural changes that promote high-affinity zinc binding by the Ccs1-bound Sod1 molecule. This adds further support to the notion that Ccs1 likely plays dual chaperoning roles during the Sod1 maturation process. Further analysis reveals that in addition to the copper-dependent roles during Sod1 activation, the N- and C-terminal domains of Ccs1 also have synergistic roles in securing both Sod1 recognition and its own active conformation. These results provide new and measurable analyses of the molecular determinants guiding Ccs1-mediated Sod1 activation.
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Affiliation(s)
- Stefanie D Boyd
- Department of Biological Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Li Liu
- Department of Biological Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Lee Bulla
- Department of Biological Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Duane D Winkler
- Department of Biological Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
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21
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Manjula R, Wright GSA, Strange RW, Padmanabhan B. Assessment of ligand binding at a site relevant to
SOD
1 oxidation and aggregation. FEBS Lett 2018; 592:1725-1737. [DOI: 10.1002/1873-3468.13055] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Ramu Manjula
- Department of Biophysics National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
| | - Gareth S. A. Wright
- Molecular Biophysics Group Institute of Integrative Biology Faculty of Health and Life Sciences University of Liverpool UK
| | | | - Balasundaram Padmanabhan
- Department of Biophysics National Institute of Mental Health and Neurosciences (NIMHANS) Bangalore India
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22
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The cysteine-reactive small molecule ebselen facilitates effective SOD1 maturation. Nat Commun 2018; 9:1693. [PMID: 29703933 PMCID: PMC5923229 DOI: 10.1038/s41467-018-04114-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 04/04/2018] [Indexed: 11/20/2022] Open
Abstract
Superoxide dismutase-1 (SOD1) mutants, including those with unaltered enzymatic activity, are known to cause amyotrophic lateral sclerosis (ALS). Several destabilizing factors contribute to pathogenicity including a reduced ability to complete the normal maturation process which comprises folding, metal cofactor acquisition, intra-subunit disulphide bond formation and dimerization. Immature SOD1 forms toxic oligomers and characteristic large insoluble aggregates within motor system cells. Here we report that the cysteine-reactive molecule ebselen efficiently confers the SOD1 intra-subunit disulphide and directs correct SOD1 folding, depopulating the globally unfolded precursor associated with aggregation and toxicity. Assisted formation of the unusual SOD1 cytosolic disulphide bond could have potential therapeutic applications. In less reducing environments, ebselen forms a selenylsulphide with Cys111 and restores the monomer–dimer equilibrium of A4V SOD1 to wild-type. Ebselen is therefore a potent bifunctional pharmacological chaperone for SOD1 that combines properties of the SOD1 chaperone hCCS and the recently licenced antioxidant drug, edaravone. Mutations in superoxide dismutase-1 (SOD1) cause amyotrophic lateral sclerosis (ALS). Here the authors present the SOD1 crystal structure bound to the small cysteine-reactive molecule ebselen and show that ebselen is a chaperone for SOD1.
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23
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Wright GSA, Saeki A, Hikima T, Nishizono Y, Hisano T, Kamaya M, Nukina K, Nishitani H, Nakamura H, Yamamoto M, Antonyuk SV, Hasnain SS, Shiro Y, Sawai H. Architecture of the complete oxygen-sensing FixL-FixJ two-component signal transduction system. Sci Signal 2018; 11:11/525/eaaq0825. [PMID: 29636388 DOI: 10.1126/scisignal.aaq0825] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The symbiotic nitrogen-fixing bacterium Bradyrhizobium japonicum is critical to the agro-industrial production of soybean because it enables the production of high yields of soybeans with little use of nitrogenous fertilizers. The FixL and FixJ two-component system (TCS) of this bacterium ensures that nitrogen fixation is only stimulated under conditions of low oxygen. When it is not bound to oxygen, the histidine kinase FixL undergoes autophosphorylation and transfers phosphate from adenosine triphosphate (ATP) to the response regulator FixJ, which, in turn, stimulates the expression of genes required for nitrogen fixation. We purified full-length B. japonicum FixL and FixJ proteins and defined their structures individually and in complex using small-angle x-ray scattering, crystallographic, and in silico modeling techniques. Comparison of active and inactive forms of FixL suggests that intramolecular signal transduction is driven by local changes in the sensor domain and in the coiled-coil region connecting the sensor and histidine kinase domains. We also found that FixJ exhibits conformational plasticity not only in the monomeric state but also in tetrameric complexes with FixL during phosphotransfer. This structural characterization of a complete TCS contributes both a mechanistic and evolutionary understanding to TCS signal relay, specifically in the context of the control of nitrogen fixation in root nodules.
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Affiliation(s)
- Gareth S A Wright
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, UK
| | - Akane Saeki
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Takaaki Hikima
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Yoko Nishizono
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Tamao Hisano
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Misaki Kamaya
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Kohei Nukina
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Hideo Nishitani
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan
| | - Hiro Nakamura
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Masaki Yamamoto
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Svetlana V Antonyuk
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, UK
| | - S Samar Hasnain
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, UK
| | - Yoshitsugu Shiro
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan. .,RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Hitomi Sawai
- Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Ako, Hyogo 678-1297, Japan. .,RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
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Effects of maturation on the conformational free-energy landscape of SOD1. Proc Natl Acad Sci U S A 2018; 115:E2546-E2555. [PMID: 29483249 DOI: 10.1073/pnas.1721022115] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating fatal syndrome characterized by very rapid degeneration of motor neurons. A leading hypothesis is that ALS is caused by toxic protein misfolding and aggregation, as also occurs in many other neurodegenerative disorders, such as prion, Alzheimer's, Parkinson's, and Huntington's diseases. A prominent cause of familial ALS is mutations in the protein superoxide dismutase (SOD1), which promote the formation of misfolded SOD1 conformers that are prone to aberrant interactions both with each other and with other cellular components. We have shown previously that immature SOD1, lacking bound Cu and Zn metal ions and the intrasubunit disulfide bond (apoSOD12SH), has a rugged free-energy surface (FES) and exchanges with four other conformations (excited states) that have millisecond lifetimes and sparse populations on the order of a few percent. Here, we examine further states of SOD1 along its maturation pathway, as well as those off-pathway resulting from metal loss that have been observed in proteinaceous inclusions. Metallation and disulfide bond formation lead to structural transformations including local ordering of the electrostatic loop and native dimerization that are observed in rare conformers of apoSOD12SH; thus, SOD1 maturation may occur via a population-switch mechanism whereby posttranslational modifications select for preexisting structures on the FES. Metallation and oxidation of SOD1 stabilize the native, mature conformation and decrease the number of detected excited conformational states, suggesting that it is the immature forms of the protein that contribute to misfolded conformations in vivo rather than the highly stable enzymatically active dimer.
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25
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Luchinat E, Barbieri L, Banci L. A molecular chaperone activity of CCS restores the maturation of SOD1 fALS mutants. Sci Rep 2017; 7:17433. [PMID: 29234142 PMCID: PMC5727297 DOI: 10.1038/s41598-017-17815-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 11/30/2017] [Indexed: 02/07/2023] Open
Abstract
Superoxide dismutase 1 (SOD1) is an important metalloprotein for cellular oxidative stress defence, that is mutated in familiar variants of Amyotrophic Lateral Sclerosis (fALS). Some mutations destabilize the apo protein, leading to the formation of misfolded, toxic species. The Copper Chaperone for SOD1 (CCS) transiently interacts with SOD1 and promotes its correct maturation by transferring copper and catalyzing disulfide bond formation. By in vitro and in-cell NMR, we investigated the role of the SOD-like domain of CCS (CCS-D2). We showed that CCS-D2 forms a stable complex with zinc-bound SOD1 in human cells, that has a twofold stabilizing effect: it both prevents the accumulation of unstructured mutant SOD1 and promotes zinc binding. We further showed that CCS-D2 interacts with apo-SOD1 in vitro, suggesting that in cells CCS stabilizes mutant apo-SOD1 prior to zinc binding. Such molecular chaperone function of CCS-D2 is novel and its implications in SOD-linked fALS deserve further investigation.
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Affiliation(s)
- Enrico Luchinat
- Magnetic Resonance Centre (CERM), University of Florence, 50019, Sesto Fiorentino, Italy.,Department of Biomedical, Clinical and Experimental Sciences, University of Florence, 50134, Florence, Italy
| | - Letizia Barbieri
- Magnetic Resonance Centre (CERM), University of Florence, 50019, Sesto Fiorentino, Italy.,Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP), 50019, Sesto Fiorentino, Italy
| | - Lucia Banci
- Magnetic Resonance Centre (CERM), University of Florence, 50019, Sesto Fiorentino, Italy. .,Department of Chemistry, University of Florence, 50019, Sesto Fiorentino, Florence, Italy.
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Srinivasan E, Rajasekaran R. Deciphering the loss of metal binding due to mutation D83G of human SOD1 protein causing FALS disease. Int J Biol Macromol 2017; 107:521-529. [PMID: 28899654 DOI: 10.1016/j.ijbiomac.2017.09.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 09/07/2017] [Accepted: 09/08/2017] [Indexed: 01/23/2023]
Abstract
Mutations in Cu/Zn superoxide dismutase 1 (SOD1) protein are found to be the causative factor, behind the majority of familial amyotrophic later sclerosis (FALS) cases. The mutations particularly on the metal (Zn) binding residues are found to increase the disease onset in the individuals suffering from FALS, while the presence of the metal ion (Zn) is essential for the catalytic activity and retaining the protein stability. Thus in our study, we focused on one such metal binding mutant (D83G) and assessed the impact of the mutation on protein structure and function. The influence of mutation was examined dynamically, using discrete molecular dynamics on both the native and mutant SOD1 protein respectively. Accordingly, the variation in conformational stability, residual flexibility and protein compactness along with the change in conformational free energy were monitored over the entire dynamic period. Moreover, the motion of native and mutant SOD1 was also observed via the essential dynamics. Besides, the disparity in Zn ion binding was inspected through distance analysis and steered molecular dynamics, correspondingly. Therefore, the study provides a better understanding over the profound effect of mutation on SOD1, both structurally and functionally, using computational approaches.
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Affiliation(s)
- E Srinivasan
- Bioinformatics lab, Department of Biotechnology, School of Biosciences and Technology, VIT University, Vellore - 632014, Tamil Nadu, India
| | - R Rajasekaran
- Bioinformatics lab, Department of Biotechnology, School of Biosciences and Technology, VIT University, Vellore - 632014, Tamil Nadu, India.
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27
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Insights into the mechanisms of copper dyshomeostasis in amyotrophic lateral sclerosis. Expert Rev Mol Med 2017; 19:e7. [PMID: 28597807 DOI: 10.1017/erm.2017.9] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a severe neuromuscular disease characterised by a progressive loss of motor neurons that usually results in paralysis and death within 2 to 5 years after disease onset. The pathophysiological mechanisms involved in ALS remain largely unknown and to date there is no effective treatment for this disease. Here, we review clinical and experimental evidence suggesting that dysregulation of copper homeostasis in the central nervous system is a crucial underlying event in motor neuron degeneration and ALS pathophysiology. We also review and discuss novel approaches seeking to target copper delivery to treat ALS. These novel approaches may be clinically relevant not only for ALS but also for other neurological disorders with abnormal copper homeostasis, such as Parkinson's, Huntington's and Prion diseases.
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28
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Enge TG, Ecroyd H, Jolley DF, Yerbury JJ, Dosseto A. Longitudinal assessment of metal concentrations and copper isotope ratios in the G93A SOD1 mouse model of amyotrophic lateral sclerosis. Metallomics 2017; 9:161-174. [DOI: 10.1039/c6mt00270f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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29
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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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