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Li B, Zhao A, Tian T, Yang X. Mechanobiological insight into brain diseases based on mechanosensitive channels: Common mechanisms and clinical potential. CNS Neurosci Ther 2024; 30:e14809. [PMID: 38923822 PMCID: PMC11197048 DOI: 10.1111/cns.14809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/15/2024] [Accepted: 06/02/2024] [Indexed: 06/28/2024] Open
Abstract
BACKGROUND As physical signals, mechanical cues regulate the neural cells in the brain. The mechanosensitive channels (MSCs) perceive the mechanical cues and transduce them by permeating specific ions or molecules across the plasma membrane, and finally trigger a series of intracellular bioelectrical and biochemical signals. Emerging evidence supports that wide-distributed, high-expressed MSCs like Piezo1 play important roles in several neurophysiological processes and neurological disorders. AIMS To systematically conclude the functions of MSCs in the brain and provide a novel mechanobiological perspective for brain diseases. METHOD We summarized the mechanical cues and MSCs detected in the brain and the research progress on the functional roles of MSCs in physiological conditions. We then concluded the pathological activation and downstream pathways triggered by MSCs in two categories of brain diseases, neurodegenerative diseases and place-occupying damages. Finally, we outlined the methods for manipulating MSCs and discussed their medical potential with some crucial outstanding issues. RESULTS The MSCs present underlying common mechanisms in different brain diseases by acting as the "transportation hubs" to transduce the distinct signal patterns: the upstream mechanical cues and the downstream intracellular pathways. Manipulating the MSCs is feasible to alter the complicated downstream processes, providing them promising targets for clinical treatment. CONCLUSIONS Recent research on MSCs provides a novel insight into brain diseases. The common mechanisms mediated by MSCs inspire a wide range of therapeutic potentials targeted on MSCs in different brain diseases.
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Affiliation(s)
- Bolong Li
- Shenzhen Key Laboratory of Translational Research for Brain Diseases, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdongChina
- College of Life SciencesUniversity of Chinese Academy of ScienceBeijingChina
| | - An‐ran Zhao
- Shenzhen Key Laboratory of Translational Research for Brain Diseases, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdongChina
- College of Life SciencesUniversity of Chinese Academy of ScienceBeijingChina
- Faculty of Life and Health SciencesShenzhen University of Advanced TechnologyShenzhenGuangdongChina
| | - Tian Tian
- Shenzhen Key Laboratory of Translational Research for Brain Diseases, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdongChina
- Faculty of Life and Health SciencesShenzhen University of Advanced TechnologyShenzhenGuangdongChina
| | - Xin Yang
- Shenzhen Key Laboratory of Translational Research for Brain Diseases, the Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdongChina
- Faculty of Life and Health SciencesShenzhen University of Advanced TechnologyShenzhenGuangdongChina
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do Nascimento Amorim MDS, Silva França ÁR, Santos-Oliveira R, Rodrigues Sanches J, Marinho Melo T, Araújo Serra Pinto B, Barbosa LRS, Alencar LMR. Atomic Force Microscopy Applied to the Study of Tauopathies. ACS Chem Neurosci 2024; 15:699-715. [PMID: 38305187 DOI: 10.1021/acschemneuro.3c00819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024] Open
Abstract
Atomic force microscopy (AFM) is a scanning probe microscopy technique which has a physical principle, the measurement of interatomic forces between a very thin tip and the surface of a sample, allowing the obtaining of quantitative data at the nanoscale, contributing to the surface study and mechanical characterization. Due to its great versatility, AFM has been used to investigate the structural and nanomechanical properties of several inorganic and biological materials, including neurons affected by tauopathies. Tauopathies are neurodegenerative diseases featured by aggregation of phosphorylated tau protein inside neurons, leading to functional loss and progressive neurotoxicity. In the broad universe of neurodegenerative diseases, tauopathies comprise the most prevalent, with Alzheimer's disease as its main representative. This review highlights the use of AFM as a suitable research technique for the study of cellular damages in tauopathies, even in early stages, allowing elucidation of pathogenic mechanisms of these diseases.
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Affiliation(s)
- Maria do Socorro do Nascimento Amorim
- Laboratory of Biophysics and Nanosystems, Department of Physics, Federal University of Maranhão, Campus Bacanga, São Luís 65080-805, Maranhão, Brazil
| | - Álefe Roger Silva França
- Laboratory of Biophysics and Nanosystems, Department of Physics, Federal University of Maranhão, Campus Bacanga, São Luís 65080-805, Maranhão, Brazil
| | - Ralph Santos-Oliveira
- Nuclear Engineering Institute, Brazilian Nuclear Energy Commission, Rio de Janeiro 21941906, Brazil
- Laboratory of Nanoradiopharmacy, Rio de Janeiro State University, Rio de Janeiro 23070200, Brazil
| | - Jonas Rodrigues Sanches
- Laboratory of Experimental Physiology, Department of Physiological Sciences, Federal University of Maranhão, Campus Bacanga, São Luís, 65080-805, Maranhão, Brazil
| | - Thamys Marinho Melo
- Laboratory of Experimental Physiology, Department of Physiological Sciences, Federal University of Maranhão, Campus Bacanga, São Luís, 65080-805, Maranhão, Brazil
| | - Bruno Araújo Serra Pinto
- Laboratory of Experimental Physiology, Department of Physiological Sciences, Federal University of Maranhão, Campus Bacanga, São Luís, 65080-805, Maranhão, Brazil
| | - Leandro R S Barbosa
- Department of General Physics, Institute of Physics, University of São Paulo, São Paulo 05508-000, SP, Brazil
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, SP, Brazil
| | - Luciana Magalhães Rebelo Alencar
- Laboratory of Biophysics and Nanosystems, Department of Physics, Federal University of Maranhão, Campus Bacanga, São Luís 65080-805, Maranhão, Brazil
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Ganegamage S, Ramirez E, Alnakhala H, Tripathi A, Nguyen CCD, Zami A, Ostafe R, Tian S, Dettmer U, Fortin JS. 1,4-Diurea- and 1,4-Dithiourea-Substituted Aromatic Derivatives Selectively Inhibit α-Synuclein Oligomer Formation In Vitro. ACS OMEGA 2024; 9:1216-1229. [PMID: 38222653 PMCID: PMC10785335 DOI: 10.1021/acsomega.3c07453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 01/16/2024]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease, affecting the elderly population worldwide. In PD, the misfolding of α-synuclein (α-syn) results in the formation of inclusions referred to as Lewy bodies (LB) in midbrain neurons of the substantia nigra and other specific brain localizations, which is associated with neurodegeneration. There are no approved strategies to reduce the formation of LB in the neurons of patients with PD. Our drug discovery program focuses on the synthesis of urea and thiourea compounds coupled with aminoindole moieties to abrogate α-syn aggregation and to slow down the progression of PD. We synthesized several urea and thiourea analogues with a central 1,4-phenyl diurea/thiourea linkage and evaluated their effectiveness in reducing α-syn aggregation with a special focus on the selective inhibition of oligomer formation among other proteins. We utilized biophysical methods such as thioflavin T (ThT) fluorescence assays, transmission electron microscopy (TEM), photoinduced cross-linking of unmodified proteins (PICUP), as well as M17D intracellular inclusion cell-based assays to evaluate the antiaggregation properties and cellular protection of our best compounds. Our results identified compound 1 as the best compound in reducing α-syn fibril formation via ThT assays. The antioligomer formation of compound 1 was subsequently superseded by compound 2. Both compounds selectively curtailed the oligomer formation of α-syn but not tau 4R isoforms (0N4R, 2N4R) or p-tau (isoform 1N4R). Compounds 1 and 2 failed to abrogate tau 0N3R fibril formation by ThT and atomic force microscopy. Compound 2 was best at reducing the formation of recombinant α-syn fibrils by TEM. In contrast to compound 2, compound 1 reduced the formation of α-syn inclusions in M17D neuroblastoma cells in a dose-dependent manner. Compound 1 may provide molecular scaffolds for the optimization of symmetric molecules for its α-syn antiaggregation activity with potential therapeutic applications and development of small molecules in PD.
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Affiliation(s)
- Susantha
K. Ganegamage
- Department
of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana 47907, United States
| | - Eduardo Ramirez
- Department
of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana 47907, United States
| | - Heba Alnakhala
- Ann
Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women’s Hospital and Harvard Medical
School, Boston, Massachusetts 02115, United States
| | - Arati Tripathi
- Ann
Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women’s Hospital and Harvard Medical
School, Boston, Massachusetts 02115, United States
| | - Cuong Calvin Duc Nguyen
- Department
of Chemistry, College of Sciences, Purdue
University, West Lafayette, Indiana 47907, United States
| | - Ashique Zami
- Purdue
Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, Indiana 47907, United States
| | - Raluca Ostafe
- Purdue
Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, Indiana 47907, United States
| | - Shiliang Tian
- Department
of Chemistry, College of Sciences, Purdue
University, West Lafayette, Indiana 47907, United States
| | - Ulf Dettmer
- Ann
Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women’s Hospital and Harvard Medical
School, Boston, Massachusetts 02115, United States
| | - Jessica S. Fortin
- Department
of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana 47907, United States
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Winkler R, Ciria M, Ahmad M, Plank H, Marcuello C. A Review of the Current State of Magnetic Force Microscopy to Unravel the Magnetic Properties of Nanomaterials Applied in Biological Systems and Future Directions for Quantum Technologies. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2585. [PMID: 37764614 PMCID: PMC10536909 DOI: 10.3390/nano13182585] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023]
Abstract
Magnetism plays a pivotal role in many biological systems. However, the intensity of the magnetic forces exerted between magnetic bodies is usually low, which demands the development of ultra-sensitivity tools for proper sensing. In this framework, magnetic force microscopy (MFM) offers excellent lateral resolution and the possibility of conducting single-molecule studies like other single-probe microscopy (SPM) techniques. This comprehensive review attempts to describe the paramount importance of magnetic forces for biological applications by highlighting MFM's main advantages but also intrinsic limitations. While the working principles are described in depth, the article also focuses on novel micro- and nanofabrication procedures for MFM tips, which enhance the magnetic response signal of tested biomaterials compared to commercial nanoprobes. This work also depicts some relevant examples where MFM can quantitatively assess the magnetic performance of nanomaterials involved in biological systems, including magnetotactic bacteria, cryptochrome flavoproteins, and magnetic nanoparticles that can interact with animal tissues. Additionally, the most promising perspectives in this field are highlighted to make the reader aware of upcoming challenges when aiming toward quantum technologies.
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Affiliation(s)
- Robert Winkler
- Christian Doppler Laboratory—DEFINE, Graz University of Technology, 8010 Graz, Austria; (R.W.); (H.P.)
| | - Miguel Ciria
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain;
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Margaret Ahmad
- Photobiology Research Group, IBPS, UMR8256 CNRS, Sorbonne Université, 75005 Paris, France;
| | - Harald Plank
- Christian Doppler Laboratory—DEFINE, Graz University of Technology, 8010 Graz, Austria; (R.W.); (H.P.)
- Graz Centre for Electron Microscopy, 8010 Graz, Austria
- Institute of Electron Microscopy, Graz University of Technology, 8010 Graz, Austria
| | - Carlos Marcuello
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain;
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
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Xin Y, Piskunen P, Suma A, Li C, Ijäs H, Ojasalo S, Seitz I, Kostiainen MA, Grundmeier G, Linko V, Keller A. Environment-Dependent Stability and Mechanical Properties of DNA Origami Six-Helix Bundles with Different Crossover Spacings. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2107393. [PMID: 35363419 DOI: 10.1002/smll.202107393] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 03/14/2022] [Indexed: 05/25/2023]
Abstract
The internal design of DNA nanostructures defines how they behave in different environmental conditions, such as endonuclease-rich or low-Mg2+ solutions. Notably, the inter-helical crossovers that form the core of such DNA objects have a major impact on their mechanical properties and stability. Importantly, crossover design can be used to optimize DNA nanostructures for target applications, especially when developing them for biomedical environments. To elucidate this, two otherwise identical DNA origami designs are presented that have a different number of staple crossovers between neighboring helices, spaced at 42- and 21- basepair (bp) intervals, respectively. The behavior of these structures is then compared in various buffer conditions, as well as when they are exposed to enzymatic digestion by DNase I. The results show that an increased number of crossovers significantly improves the nuclease resistance of the DNA origami by making it less accessible to digestion enzymes but simultaneously lowers its stability under Mg2+ -free conditions by reducing the malleability of the structures. Therefore, these results represent an important step toward rational, application-specific DNA nanostructure design.
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Affiliation(s)
- Yang Xin
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098, Paderborn, Germany
| | - Petteri Piskunen
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, Aalto, 00076, Finland
| | - Antonio Suma
- Dipartimento di Fisica, Università di Bari and Sezione INFN di Bari, Bari, 70126, Italy
| | - Changyong Li
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098, Paderborn, Germany
| | - Heini Ijäs
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, Aalto, 00076, Finland
| | - Sofia Ojasalo
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, Aalto, 00076, Finland
| | - Iris Seitz
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, Aalto, 00076, Finland
| | - Mauri A Kostiainen
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, Aalto, 00076, Finland
| | - Guido Grundmeier
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098, Paderborn, Germany
| | - Veikko Linko
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, Aalto, 00076, Finland
| | - Adrian Keller
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098, Paderborn, Germany
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Hornakova L, Sinsky J, Janubova M, Mederlyova A, Paulenka Ivanovova N, Piestansky J, Kovac A, Galba J, Skrabana R, Cehlar O. Interaction kinetics reveal distinct properties of conformational ensembles of three-repeat and four-repeat tau proteins. FEBS Lett 2022; 596:1178-1189. [PMID: 35322890 DOI: 10.1002/1873-3468.14339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/23/2022] [Accepted: 03/10/2022] [Indexed: 11/06/2022]
Abstract
Tau protein is an intrinsically disordered protein. Its physiological state is best described as a conformational ensemble (CE) of metastable structures interconverting on the local and molecular scale. The monoclonal antibody DC39C recognizes a linear C-terminal tau epitope, and as the tau interaction partner, its binding parameters report about tau CE. Association kinetics of DC39C binding, together with crosslinking mass spectrometry, show differences in the accessibility of the C-terminus in CEs of tau isoforms. Furthermore, removal of the C-terminus accelerated the aggregation kinetics of three-repeat tau proteins. Our results suggest a novel mechanism of splicing-driven regulation of the tau C-terminal domain with consequences on the specific roles of tau isoforms in microtubule assembly and pathological aggregation.
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Affiliation(s)
- Lenka Hornakova
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska cesta 9, 84510, Bratislava, Slovak Republic.,Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Ilkovicova 6, 84215, Bratislava, Slovak Republic.,Institute of Medical Chemistry, Biochemistry and Clinical Biochemistry, Medical Faculty, Comenius University, Sasinkova 2, 811 08, Bratislava, Slovak Republic
| | - Jakub Sinsky
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska cesta 9, 84510, Bratislava, Slovak Republic
| | - Maria Janubova
- Axon Neuroscience R&D Services SE, Dvorakovo Nabrezie 10, 81102, Bratislava, Slovak Republic.,Institute of Medical Chemistry, Biochemistry and Clinical Biochemistry, Medical Faculty, Comenius University, Sasinkova 2, 811 08, Bratislava, Slovak Republic
| | - Anna Mederlyova
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska cesta 9, 84510, Bratislava, Slovak Republic
| | | | - Juraj Piestansky
- Axon Neuroscience R&D Services SE, Dvorakovo Nabrezie 10, 81102, Bratislava, Slovak Republic.,Department of Pharmaceutical Analysis and Nuclear Pharmacy, Faculty of Pharmacy, Comenius University, Odbojarov 10, 83232, Bratislava, Slovak Republic.,Toxicological and Antidoping Center, Faculty of Pharmacy, Comenius University in Bratislava, Odbojarov 10, 832 32, Bratislava, Slovakia
| | - Andrej Kovac
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska cesta 9, 84510, Bratislava, Slovak Republic.,Axon Neuroscience R&D Services SE, Dvorakovo Nabrezie 10, 81102, Bratislava, Slovak Republic
| | - Jaroslav Galba
- Axon Neuroscience R&D Services SE, Dvorakovo Nabrezie 10, 81102, Bratislava, Slovak Republic.,Biomedical Research Center of the Slovak Academy of Sciences, Dubravska cesta 9, 84510, Bratislava, Slovakia
| | - Rostislav Skrabana
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska cesta 9, 84510, Bratislava, Slovak Republic.,Axon Neuroscience R&D Services SE, Dvorakovo Nabrezie 10, 81102, Bratislava, Slovak Republic
| | - Ondrej Cehlar
- Institute of Neuroimmunology, Slovak Academy of Sciences, Dubravska cesta 9, 84510, Bratislava, Slovak Republic
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Banerjee S, Ghosh A. Structurally Distinct Polymorphs of Tau Aggregates Revealed by Nanoscale Infrared Spectroscopy. J Phys Chem Lett 2021; 12:11035-11041. [PMID: 34747175 PMCID: PMC8967399 DOI: 10.1021/acs.jpclett.1c02660] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Aggregation of the tau protein plays a central role in several neurodegenerative diseases collectively known as tauopathies, including Alzheimer's and Parkinson's disease. Tau misfolds into fibrillar β sheet structures that constitute the paired helical filaments found in neurofibrillary tangles. It is known that there can be significant structural heterogeneities in tau aggregates associated with different diseases. However, while structures of mature fibrils have been studied, the structural distributions in early-stage tau aggregates is not well-understood. In the present study, we use atomic force microscopy-IR to investigate nanoscale spectra of individual tau fibrils at different stages of aggregation and demonstrate the presence of multiple fibrillar polymorphs that exhibit different secondary structures. We further show that mature fibrils contain significant amounts of antiparallel β sheets. Our results are the very first application of nanoscale infrared spectroscopy to tau aggregates and underscore the promise of spatially resolved infrared spectroscopy for investigating protein aggregation.
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Affiliation(s)
| | - Ayanjeet Ghosh
- Corresponding Author Ayanjeet Ghosh - Department of Chemistry and Biochemistry, The University of Alabama, 1007E Shelby Hall, Tuscaloosa, AL 35401, USA.
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Structural mapping techniques distinguish the surfaces of fibrillar 1N3R and 1N4R human tau. J Biol Chem 2021; 297:101252. [PMID: 34592311 PMCID: PMC8551503 DOI: 10.1016/j.jbc.2021.101252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 09/21/2021] [Accepted: 09/24/2021] [Indexed: 12/02/2022] Open
Abstract
The rigid core of intracellular tau filaments from Alzheimer's disease (AD), Pick's disease (PiD), and Corticobasal disease (CBD) brains has been shown to differ in their cryo-EM atomic structure. Despite providing critical information on the intimate arrangement of a fraction of htau molecule within the fibrillar scaffold, the cryo-EM studies neither yield a complete picture of tau fibrillar assemblies structure nor contribute insights into the surfaces that define their interactions with numerous cellular components. Here, using proteomic approaches such as proteolysis and molecular covalent painting, we mapped the exposed amino acid stretches at the surface and those constituting the fibrillar core of in vitro-assembled fibrils of human htau containing one N-terminal domain and three (1N3R) or four (1N4R) C-terminal microtubule-binding repeat domains as a result of alternative splicing. Using limited proteolysis, we identified the proteolytic fragments composing the molecular “bar-code” for each type of fibril. Our results are in agreement with structural data reported for filamentous tau from AD, PiD, and CBD cases predigested with the protease pronase. Finally, we report two amino acid stretches, exposed to the solvent in 1N4R not in 1N3R htau, which distinguish the surfaces of these two kinds of fibrils. Our findings open new perspectives for the design of highly specific ligands with diagnostic and therapeutic potential.
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