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Tettevi EJ, Kuevi DNO, Sumabe BK, Simpong DL, Maina MB, Dongdem JT, Osei-Atweneboana MY, Ocloo A. In Silico Identification of a Potential TNF-Alpha Binder Using a Structural Similarity: A Potential Drug Repurposing Approach to the Management of Alzheimer's Disease. Biomed Res Int 2024; 2024:9985719. [PMID: 38221912 PMCID: PMC10787656 DOI: 10.1155/2024/9985719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 11/25/2023] [Accepted: 12/13/2023] [Indexed: 01/16/2024]
Abstract
Introduction Alzheimer's disease (AD) is a neurodegenerative disorder with no conclusive remedy. Yohimbine, found in Rauwolfia vomitoria, may reduce brain inflammation by targeting tumour necrosis factor-alpha (TNFα), implicated in AD pathogenesis. Metoserpate, a synthetic compound, may inhibit TNFα. The study is aimed at assessing the potential utility of repurposing metoserpate for TNFα inhibition to reduce neuronal damage and inflammation in AD. The development of safe and effective treatments for AD is crucial to address the growing burden of the disease, which is projected to double over the next two decades. Methods Our study repurposed an FDA-approved drug as TNFα inhibitor for AD management using structural similarity studies, molecular docking, and molecular dynamics simulations. Yohimbine was used as a reference compound. Molecular docking used SeeSAR, and molecular dynamics simulation used GROMACS. Results Metoserpate was selected from 10 compounds similar to yohimbine based on pharmacokinetic properties and FDA approval status. Molecular docking and simulation studies showed a stable interaction between metoserpate and TNFα over 100 ns (100000 ps). This suggests a reliable and robust interaction between the protein and ligand, supporting the potential utility of repurposing metoserpate for TNFα inhibition in AD treatment. Conclusion Our study has identified metoserpate, a previously FDA-approved antihypertensive agent, as a promising candidate for inhibiting TNFα in the management of AD.
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Affiliation(s)
- Edward Jenner Tettevi
- Department of Biochemistry, Cell and Molecular Biology, School of Biological Science, University of Ghana, Legon, Accra, P.O. Box LG 25, Ghana
- West African Centre for Cell Biology of Infectious Pathogens, School of Biological Science, University of Ghana, Legon, Accra, P.O. Box LG 25, Ghana
- Biomedical and Public Health Research Unit, Council for Scientific and Industrial Research-Water Research Institute, Accra, P.O. Box M 32, Ghana
| | - Deryl Nii Okantey Kuevi
- Biomedical and Public Health Research Unit, Council for Scientific and Industrial Research-Water Research Institute, Accra, P.O. Box M 32, Ghana
| | - Balagra Kasim Sumabe
- Biomedical and Public Health Research Unit, Council for Scientific and Industrial Research-Water Research Institute, Accra, P.O. Box M 32, Ghana
| | - David Larbi Simpong
- Department of Medical Laboratory Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana
| | - Mahmoud B. Maina
- Serpell Laboratory, Sussex Neuroscience, School of Life Sciences, University of Sussex, UK
- Biomedical Science Research and Training Centre, College of Medical Sciences, Yobe State University, Damaturu, Nigeria
| | - Julius T. Dongdem
- Department of Biochemistry and Molecular Medicine, School of Medicine, University for Development Studies, Tamale Campus, Ghana
| | - Mike Y. Osei-Atweneboana
- Biomedical and Public Health Research Unit, Council for Scientific and Industrial Research-Water Research Institute, Accra, P.O. Box M 32, Ghana
- CSIR-College of Science and Technology, 2nd CSIR Close, Airport Residential Area, Behind Golden Tulip Hotel, Greater Accra Region, Ghana
| | - Augustine Ocloo
- Department of Biochemistry, Cell and Molecular Biology, School of Biological Science, University of Ghana, Legon, Accra, P.O. Box LG 25, Ghana
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Maina MB, Al-Hilaly YK, Serpell LC. Dityrosine cross-linking and its potential roles in Alzheimer's disease. Front Neurosci 2023; 17:1132670. [PMID: 37034163 PMCID: PMC10075315 DOI: 10.3389/fnins.2023.1132670] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 03/01/2023] [Indexed: 04/11/2023] Open
Abstract
Oxidative stress is a significant source of damage that accumulates during aging and contributes to Alzheimer's disease (AD) pathogenesis. Oxidation of proteins can give rise to covalent links between adjacent tyrosines known as dityrosine (DiY) cross-linking, amongst other modifications, and this observation suggests that DiY could serve as a biomarker of accumulated oxidative stress over the lifespan. Many studies have focused on understanding the contribution of DiY to AD pathogenesis and have revealed that DiY crosslinks can be found in both Aβ and tau deposits - the two key proteins involved in the formation of amyloid plaques and tau tangles, respectively. However, there is no consensus yet in the field on the impact of DiY on Aβ and tau function, aggregation, and toxicity. Here we review the current understanding of the role of DiY on Aβ and tau gathered over the last 20 years since the first observation, and discuss the effect of this modification for Aβ and tau aggregation, and its potential as a biomarker for AD.
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Affiliation(s)
- Mahmoud B. Maina
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, United Kingdom
- Biomedical Science Research and Training Centre, College of Medical Sciences, Yobe State University, Damaturu, Nigeria
| | - Youssra K. Al-Hilaly
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, United Kingdom
- Department of Chemistry, College of Science, Mustansiriyah University, Baghdad, Iraq
| | - Louise C. Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, United Kingdom
- *Correspondence: Louise C. Serpell,
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3
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Maina MB, Al-Hilaly YK, Oakley S, Burra G, Khanom T, Biasetti L, Mengham K, Marshall K, Harrington CR, Wischik CM, Serpell LC. Dityrosine Cross-links are Present in Alzheimer's Disease-derived Tau Oligomers and Paired Helical Filaments (PHF) which Promotes the Stability of the PHF-core Tau (297-391) In Vitro. J Mol Biol 2022; 434:167785. [PMID: 35961386 DOI: 10.1016/j.jmb.2022.167785] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 08/02/2022] [Accepted: 08/03/2022] [Indexed: 11/30/2022]
Abstract
A characteristic hallmark of Alzheimer's Disease (AD) is the pathological aggregation and deposition of tau into paired helical filaments (PHF) in neurofibrillary tangles (NFTs). Oxidative stress is an early event during AD pathogenesis and is associated with tau-mediated AD pathology. Oxidative environments can result in the formation of covalent dityrosine crosslinks that can increase protein stability and insolubility. Dityrosine cross-linking has been shown in Aβ plaques in AD and α-synuclein aggregates in Lewy bodies in ex vivo tissue sections, and this modification may increase the insolubility of these aggregates and their resistance to degradation. Using the PHF-core tau fragment (residues 297 - 391) as a model, we have previously demonstrated that dityrosine formation traps tau assemblies to reduce further elongation. However, it is unknown whether dityrosine crosslinks are found in tau deposits in vivo in AD and its relevance to disease mechanism is unclear. Here, using transmission electron microscope (TEM) double immunogold-labelling, we reveal that neurofibrillary NFTs in AD are heavily decorated with dityrosine crosslinks alongside tau. Single immunogold-labelling TEM and fluorescence spectroscopy revealed the presence of dityrosine on AD brain-derived tau oligomers and fibrils. Using the tau (297-391) PHF-core fragment as a model, we further showed that prefibrillar tau species are more amenable to dityrosine crosslinking than tau fibrils. Dityrosine formation results in heat and SDS stability of oxidised prefibrillar and fibrillar tau assemblies. This finding has implications for understanding the mechanism governing the insolubility and toxicity of tau assemblies in vivo.
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Affiliation(s)
- Mahmoud B Maina
- Sussex Neuroscience, School of Life Sciences, University of Sussex UK; Biomedical Science Research and Training Centre, Yobe State University, Nigeria. https://twitter.com/mahmoudbukar
| | - Youssra K Al-Hilaly
- Sussex Neuroscience, School of Life Sciences, University of Sussex UK; Chemistry Department, College of Sciences, Mustansiriyah University, Baghdad, Iraq
| | - Sebastian Oakley
- Sussex Neuroscience, School of Life Sciences, University of Sussex UK
| | - Gunasekhar Burra
- Sussex Neuroscience, School of Life Sciences, University of Sussex UK; Analytical Development Biologics, Biopharmaceutical Development, Syngene International Limited, Biocon Park, Bommasandra Jigani Link Road, Bangalore 560009, India
| | - Tahmida Khanom
- Sussex Neuroscience, School of Life Sciences, University of Sussex UK
| | - Luca Biasetti
- Sussex Neuroscience, School of Life Sciences, University of Sussex UK
| | - Kurtis Mengham
- Sussex Neuroscience, School of Life Sciences, University of Sussex UK
| | - Karen Marshall
- Sussex Neuroscience, School of Life Sciences, University of Sussex UK
| | - Charles R Harrington
- Institute of Medical Sciences, University of Aberdeen, UK; TauRx Therapeutics Ltd, Aberdeen, UK
| | - Claude M Wischik
- Institute of Medical Sciences, University of Aberdeen, UK; TauRx Therapeutics Ltd, Aberdeen, UK
| | - Louise C Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex UK.
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Maina MB, Ahmad U, Ibrahim HA, Hamidu SK, Nasr FE, Salihu AT, Abushouk AI, Abdurrazak M, Awadelkareem MA, Amin A, Imam A, Akinrinade ID, Yakubu AH, Azeez IA, Mohammed YG, Adamu AA, Ibrahim HB, Bukar AM, Yaro AU, Goni BW, Prieto-Godino LL, Baden T. Two decades of neuroscience publication trends in Africa. Nat Commun 2021; 12:3429. [PMID: 34103514 PMCID: PMC8187719 DOI: 10.1038/s41467-021-23784-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 05/11/2021] [Indexed: 12/12/2022] Open
Abstract
Neuroscience research in Africa remains sparse. Devising new policies to boost Africa's neuroscience landscape is imperative, but these must be based on accurate data on research outputs which is largely lacking. Such data must reflect the heterogeneity of research environments across the continent's 54 countries. Here, we analyse neuroscience publications affiliated with African institutions between 1996 and 2017. Of 12,326 PubMed indexed publications, 5,219 show clear evidence that the work was performed in Africa and led by African-based researchers - on average ~5 per country and year. From here, we extract information on journals and citations, funding, international coauthorships and techniques used. For reference, we also extract the same metrics from 220 randomly selected publications each from the UK, USA, Australia, Japan and Brazil. Our dataset provides insights into the current state of African neuroscience research in a global context.
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Affiliation(s)
- M B Maina
- School of Life Sciences, University of Sussex, Brighton, UK.
- Biomedical Science Research and Training Centre, College of Medical Sciences, Yobe State University, Damaturu, Nigeria.
- TReND in Africa (www.TReNDinAfrica.org), Brighton, UK.
| | - U Ahmad
- Medical Genetics Laboratory, Genetics and Regenerative Medicine Research Centre, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
- Department of Anatomy, Faculty of Basic Medical Sciences, Bauchi State University, PMB 65, Gadau, Nigeria
| | - H A Ibrahim
- College of Medicine, Misr University for Science and Technology, Giza, Egypt
| | - S K Hamidu
- TReND in Africa (www.TReNDinAfrica.org), Brighton, UK
- Department of Human Anatomy, Faculty of Basic Medical Sciences, Gombe State University, Gombe, Nigeria
| | - F E Nasr
- TReND in Africa (www.TReNDinAfrica.org), Brighton, UK
- Faculty of Science, Alexandria University, Alexandria, Egypt
| | - A T Salihu
- Non-invasive Brain Stimulation and Neuroplasticity Laboratory, Department of Physiotherapy, School of Primary and Allied Healthcare, Faculty of Medicine Nursing and Health Sciences, Monash University, Melbourne, Australia
- Department of Physiotherapy, Hasiya Bayero Paediatric Hospital, Kano, Nigeria
| | - A I Abushouk
- Harvard Medical School, Harvard University, Boston, MA, USA
- Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - M Abdurrazak
- Sheka Primary Health Care Kumbotso, Kano, Nigeria
| | - M A Awadelkareem
- TReND in Africa (www.TReNDinAfrica.org), Brighton, UK
- Faculty of Medical Laboratory Sciences, Al-Neelain University, Khartoum, Sudan
- UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
- Department of Neuroscience Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - A Amin
- TReND in Africa (www.TReNDinAfrica.org), Brighton, UK
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Department of Physiology, Faculty of Basic Medical Sciences, University of Ilorin, Ilorin, Nigeria
| | - A Imam
- Department of Anatomy, Faculty of Basic Medical Sciences, University of Ilorin, Ilorin, Nigeria
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - I D Akinrinade
- TReND in Africa (www.TReNDinAfrica.org), Brighton, UK
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - A H Yakubu
- TReND in Africa (www.TReNDinAfrica.org), Brighton, UK
- Faculty of Pharmacy, University of Maiduguri, Maiduguri, Nigeria
| | - I A Azeez
- Department of Neuroscience Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Department of Veterinary Anatomy, Faculty of Veterinary Medicine, University of Jos, Jos, Nigeria
| | - Y G Mohammed
- TReND in Africa (www.TReNDinAfrica.org), Brighton, UK
- Department of Human Anatomy, Faculty of Basic Medical Sciences, Gombe State University, Gombe, Nigeria
- Department of Biology, Neurobiology group, University of Konstanz, Baden Wurttemberg, Germany
| | - A A Adamu
- Department of Physiotherapy, Aminu Kano Teaching Hospital, Kano, Nigeria
| | - H B Ibrahim
- Department of Pharmacy, Federal Medical Centre, Katsina, Nigeria
| | - A M Bukar
- Centre for Visual Computing, University of Bradford, Bradford, UK
| | - A U Yaro
- College of Medical Sciences, University of Maiduguri, Maiduguri, Nigeria
| | - B W Goni
- Department of Medicine, Yobe State University Teaching Hospital Damaturu PMB 1072, Damaturu, Yobe State, Nigeria
| | - L L Prieto-Godino
- TReND in Africa (www.TReNDinAfrica.org), Brighton, UK.
- Francis Crick Institute, London, UK.
| | - T Baden
- School of Life Sciences, University of Sussex, Brighton, UK.
- TReND in Africa (www.TReNDinAfrica.org), Brighton, UK.
- Institute of Ophthalmic Research, University of Tübingen, Tübingen, Germany.
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5
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Maina MB, Al-Hilaly YK, Burra G, Rickard JE, Harrington CR, Wischik CM, Serpell LC. Oxidative Stress Conditions Result in Trapping of PHF-Core Tau (297-391) Intermediates. Cells 2021; 10:cells10030703. [PMID: 33809978 PMCID: PMC8005035 DOI: 10.3390/cells10030703] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/12/2021] [Accepted: 03/15/2021] [Indexed: 01/23/2023] Open
Abstract
The self-assembly of tau into paired helical filaments (PHFs) in neurofibrillary tangles (NFTs) is a significant event in Alzheimer's disease (AD) pathogenesis. Numerous post-translational modifications enhance or inhibit tau assembly into NFTs. Oxidative stress, which accompanies AD, induces multiple post-translational modifications in proteins, including the formation of dityrosine (DiY) cross-links. Previous studies have revealed that metal-catalysed oxidation (MCO) using Cu2+ and H2O2 leads to the formation of DiY cross-links in two misfolding proteins, Aβ and α-synuclein, associated with AD and Parkinson's disease respectively. The effect of MCO on tau remains unknown. Here, we examined the effect of MCO and ultra-violet oxidation to study the influence of DiY cross-linking on the self-assembly of the PHF-core tau fragment. We report that DiY cross-linking facilitates tau assembly into tau oligomers that fail to bind thioflavin S, lack β-sheet structure and prevents their elongation into filaments. At a higher concentration, Cu2+ (without H2O2) also facilitates the formation of these tau oligomers. The DiY cross-linked tau oligomers do not cause cell death. Our findings suggest that DiY cross-linking of pre-assembled tau promotes the formation of soluble tau oligomers that show no acute impact on cell viability.
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Affiliation(s)
- Mahmoud B. Maina
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK; (M.B.M.); (Y.K.A.-H.); (G.B.)
- College of Medical Sciences, Yobe State University, Damaturu P.M.B. 1144, Nigeria
| | - Youssra K. Al-Hilaly
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK; (M.B.M.); (Y.K.A.-H.); (G.B.)
- Chemistry Department, College of Sciences, Mustansiriyah University, Baghdad, Iraq
| | - Gunasekhar Burra
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK; (M.B.M.); (Y.K.A.-H.); (G.B.)
- Analytical Research and Development, Pharma Division, Biological E. Limited, Genome Valley, IKP-Shameerpet, Hyderabad 500 078, Telangana, India
| | - Janet E. Rickard
- Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZP, UK; (J.E.R.); (C.R.H.); (C.M.W.)
| | - Charles R. Harrington
- Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZP, UK; (J.E.R.); (C.R.H.); (C.M.W.)
- TauRx Therapeutics Ltd., Aberdeen AB24 5RP, UK
| | - Claude M. Wischik
- Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZP, UK; (J.E.R.); (C.R.H.); (C.M.W.)
- TauRx Therapeutics Ltd., Aberdeen AB24 5RP, UK
| | - Louise C. Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK; (M.B.M.); (Y.K.A.-H.); (G.B.)
- Correspondence:
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6
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Burra G, Maina MB, Serpell LC, Thakur AK. Nucleation-dependent Aggregation Kinetics of Yeast Sup35 Fragment GNNQQNY. J Mol Biol 2020; 433:166732. [PMID: 33279578 DOI: 10.1016/j.jmb.2020.166732] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 11/25/2020] [Accepted: 11/30/2020] [Indexed: 10/22/2022]
Abstract
An N-terminal hepta-peptide sequence of yeast prion protein Sup35 with the sequence GNNQQNY is widely used as a model system for amyloid fibril formation. In this study, we used a reproducible solubilisation protocol that allows the generation of a homogenous monomeric solution of GNNQQNY to uncover the molecular details of its self-assembly mechanism. The aggregation kinetics data show that the GNNQQNY sequence follows nucleation-dependent aggregation kinetics with a critical nucleus of size ~7 monomers and that the efficiency of nucleation were found to be inversely related to the reaction temperature. The nucleus reduces the thermodynamic energy barrier by acting as a template for further self-assembly and results in highly ordered amyloid fibrils. The fibers grown at different temperatures showed similar Thioflavin T fluorescence, Congo-red binding and β-sheet rich structures displaying a characteristic cross-β diffraction pattern. These aggregates also share morphological and structural identity with those reported earlier. The mature GNNQQNY fibers did not exert significant oxidative stress or cytotoxicity upon incubating with differentiated SHSY5Y cells. To our knowledge, this is the first study to experimentally validate previous nucleus size predictions based on theoretical and molecular dynamics simulations. These findings provide the basis for understanding the kinetics and thermodynamics of amyloid nucleation and elongation of amyloidogenic proteins/peptides associated with many systemic and neurodegenerative diseases.
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Affiliation(s)
- Gunasekhar Burra
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India; Sussex Neuroscience, School of Life Sciences, University of Sussex, UK.
| | - Mahmoud B Maina
- Sussex Neuroscience, School of Life Sciences, University of Sussex, UK; College of Medical Sciences, Yobe State University, Nigeria
| | - Louise C Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, UK
| | - Ashwani K Thakur
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, India.
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7
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Oakley SS, Maina MB, Marshall KE, Al-Hilaly YK, Harrington CR, Wischik CM, Serpell LC. Tau Filament Self-Assembly and Structure: Tau as a Therapeutic Target. Front Neurol 2020; 11:590754. [PMID: 33281730 PMCID: PMC7688747 DOI: 10.3389/fneur.2020.590754] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 09/04/2020] [Indexed: 12/12/2022] Open
Abstract
Tau plays an important pathological role in a group of neurodegenerative diseases called tauopathies, including Alzheimer's disease, Pick's disease, chronic traumatic encephalopathy and corticobasal degeneration. In each disease, tau self-assembles abnormally to form filaments that deposit in the brain. Tau is a natively unfolded protein that can adopt distinct structures in different pathological disorders. Cryo-electron microscopy has recently provided a series of structures for the core of the filaments purified from brain tissue from patients with different tauopathies and revealed that they share a common core region, while differing in their specific conformation. This structurally resolvable part of the core is contained within a proteolytically stable core region from the repeat domain initially isolated from AD tau filaments. Tau has recently become an important target for therapy. Recent work has suggested that the prevention of tau self-assembly may be effective in slowing the progression of Alzheimer's disease and other tauopathies. Here we review the work that explores the importance of tau filament structures and tau self-assembly mechanisms, as well as examining model systems that permit the exploration of the mode of action of potential inhibitors.
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Affiliation(s)
- Sebastian S Oakley
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Mahmoud B Maina
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom.,College of Medical Sciences, Yobe State University, Damaturu, Nigeria
| | - Karen E Marshall
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Youssra K Al-Hilaly
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom.,Chemistry Department, College of Science, Mustansiriyah University, Baghdad, Iraq
| | - Charlie R Harrington
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, United Kingdom.,TauRx Therapeutics Ltd., Aberdeen, United Kingdom
| | - Claude M Wischik
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, United Kingdom.,TauRx Therapeutics Ltd., Aberdeen, United Kingdom
| | - Louise C Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
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8
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Maina MB, Bailey LJ, Doherty AJ, Serpell LC. The Involvement of Aβ42 and Tau in Nucleolar and Protein Synthesis Machinery Dysfunction. Front Cell Neurosci 2018; 12:220. [PMID: 30123109 PMCID: PMC6086011 DOI: 10.3389/fncel.2018.00220] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/09/2018] [Indexed: 01/29/2023] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia and is distinguished from other dementias by observation of extracellular Amyloid-β (Aβ) plaques and intracellular neurofibrillary tangles, comprised of fibrils of Aβ and tau protein, respectively. At early stages, AD is characterized by minimal neurodegeneration, oxidative stress, nucleolar stress, and altered protein synthesis machinery. It is generally believed that Aβ oligomers are the neurotoxic species and their levels in the AD brain correlate with the severity of dementia suggesting that they play a critical role in the pathogenesis of the disease. Here, we show that the incubation of differentiated human neuroblastoma cells (SHSY5Y) with freshly prepared Aβ42 oligomers initially resulted in oxidative stress and subtle nucleolar stress in the absence of DNA damage or cell death. The presence of exogenous Aβ oligomers resulted in altered nuclear tau levels as well as phosphorylation state, leading to altered distribution of nucleolar tau associated with nucleolar stress. These markers of cellular dysfunction worsen over time alongside a reduction in ribosomal RNA synthesis and processing, a decrease in global level of newly synthesized RNA and reduced protein synthesis. The interplay between Aβ and tau in AD remains intriguing and Aβ toxicity has been linked to tau phosphorylation and changes in localization. These findings provide evidence for the involvement of Aβ42 effects on nucleolar tau and protein synthesis machinery dysfunction in cultured cells. Protein synthesis dysfunction is observed in mild cognitive impairment and early AD in the absence of significant neuronal death.
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Affiliation(s)
- Mahmoud B Maina
- School of Life Sciences, University of Sussex, Brighton, United Kingdom.,Department of Human Anatomy, College of Medical Sciences, Gombe State University, Gombe, Nigeria
| | - Laura J Bailey
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Aidan J Doherty
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Louise C Serpell
- School of Life Sciences, University of Sussex, Brighton, United Kingdom
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Maina MB, Bailey LJ, Wagih S, Biasetti L, Pollack SJ, Quinn JP, Thorpe JR, Doherty AJ, Serpell LC. The involvement of tau in nucleolar transcription and the stress response. Acta Neuropathol Commun 2018; 6:70. [PMID: 30064522 PMCID: PMC6066928 DOI: 10.1186/s40478-018-0565-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 06/30/2018] [Indexed: 12/16/2022] Open
Abstract
Tau is known for its pathological role in neurodegenerative diseases, including Alzheimer's disease (AD) and other tauopathies. Tau is found in many subcellular compartments such as the cytosol and the nucleus. Although its normal role in microtubule binding is well established, its nuclear role is still unclear. Here, we reveal that tau localises to the nucleolus in undifferentiated and differentiated neuroblastoma cells (SHSY5Y), where it associates with TIP5, a key player in heterochromatin stability and ribosomal DNA (rDNA) transcriptional repression. Immunogold labelling on human brain sample confirms the physiological relevance of this finding by showing tau within the nucleolus colocalises with TIP5. Depletion of tau results in an increase in rDNA transcription with an associated decrease in heterochromatin and DNA methylation, suggesting that under normal conditions tau is involved in silencing of the rDNA. Cellular stress induced by glutamate causes nucleolar stress associated with the redistribution of nucleolar non-phosphorylated tau, in a similar manner to fibrillarin, and nuclear upsurge of phosphorylated tau (Thr231) which doesn't colocalise with fibrillarin or nucleolar tau. This suggests that stress may impact on different nuclear tau species. In addition to involvement in rDNA transcription, nucleolar non-phosphorylated tau also undergoes stress-induced redistribution similar to many nucleolar proteins.
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MESH Headings
- Brain/metabolism
- Brain/ultrastructure
- Cell Differentiation/physiology
- Cell Line, Tumor
- Cell Nucleolus/drug effects
- Cell Nucleolus/metabolism
- Cell Nucleolus/ultrastructure
- Chromosomal Proteins, Non-Histone/metabolism
- Chromosomal Proteins, Non-Histone/ultrastructure
- DNA, Ribosomal/genetics
- DNA, Ribosomal/metabolism
- Excitatory Amino Acid Agonists/pharmacology
- Gene Expression Regulation, Neoplastic/drug effects
- Gene Expression Regulation, Neoplastic/genetics
- Glutamic Acid/pharmacology
- Heterochromatin/physiology
- Histones/metabolism
- Humans
- Immunoprecipitation
- Microscopy, Confocal
- Microscopy, Electron
- Neuroblastoma/pathology
- Neuroblastoma/ultrastructure
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Protein Transport/drug effects
- RNA, Messenger
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Transcription, Genetic/drug effects
- Transfection
- tau Proteins/genetics
- tau Proteins/metabolism
- tau Proteins/ultrastructure
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Affiliation(s)
- Mahmoud B Maina
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
- Department of Human Anatomy, College of Medical Science, Gombe State University, Gombe, Nigeria
| | - Laura J Bailey
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, BN1 9RQ, UK
| | - Sherin Wagih
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - Luca Biasetti
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - Saskia J Pollack
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - James P Quinn
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - Julian R Thorpe
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - Aidan J Doherty
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, BN1 9RQ, UK
| | - Louise C Serpell
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK.
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