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Bhole RP, Chikhale RV, Rathi KM. Current biomarkers and treatment strategies in Alzheimer disease: An overview and future perspectives. IBRO Neurosci Rep 2024; 16:8-42. [PMID: 38169888 PMCID: PMC10758887 DOI: 10.1016/j.ibneur.2023.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 11/06/2023] [Accepted: 11/09/2023] [Indexed: 01/05/2024] Open
Abstract
Alzheimer's disease (AD), a progressive degenerative disorder first identified by Alois Alzheimer in 1907, poses a significant public health challenge. Despite its prevalence and impact, there is currently no definitive ante mortem diagnosis for AD pathogenesis. By 2050, the United States may face a staggering 13.8 million AD patients. This review provides a concise summary of current AD biomarkers, available treatments, and potential future therapeutic approaches. The review begins by outlining existing drug targets and mechanisms in AD, along with a discussion of current treatment options. We explore various approaches targeting Amyloid β (Aβ), Tau Protein aggregation, Tau Kinases, Glycogen Synthase kinase-3β, CDK-5 inhibitors, Heat Shock Proteins (HSP), oxidative stress, inflammation, metals, Apolipoprotein E (ApoE) modulators, and Notch signaling. Additionally, we examine the historical use of Estradiol (E2) as an AD therapy, as well as the outcomes of Randomized Controlled Trials (RCTs) that evaluated antioxidants (e.g., vitamin E) and omega-3 polyunsaturated fatty acids as alternative treatment options. Notably, positive effects of docosahexaenoic acid nutriment in older adults with cognitive impairment or AD are highlighted. Furthermore, this review offers insights into ongoing clinical trials and potential therapies, shedding light on the dynamic research landscape in AD treatment.
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Affiliation(s)
- Ritesh P. Bhole
- Department of Pharmaceutical Chemistry, Dr. D. Y. Patil institute of Pharmaceutical Sciences & Research, Pimpri, Pune, India
- Dr. D. Y. Patil Dental College and Hospital, Dr. D. Y. Patil Vidyapeeth, Pimpri, Pune 411018, India
| | | | - Karishma M. Rathi
- Department of Pharmacy Practice, Dr. D. Y. Patil institute of Pharmaceutical Sciences & Research, Pimpri, Pune, India
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2
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Abdul Vahid A, Oliyantakath Hassan MS, Sahayaraj AE, Babu AT, Kizhakkeduth ST, Vijayan V. Modulation of Primary and Secondary Processes in Tau Fibril Formation by Salt-Induced Dynamics. ACS Chem Neurosci 2024; 15:1242-1253. [PMID: 38433380 DOI: 10.1021/acschemneuro.3c00852] [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: 03/05/2024] Open
Abstract
The initial stages of amyloid fibrilization begin with the monomers populating aggregation-prone conformers. Characterization of such aggregation-prone conformers is crucial in the study of neurodegenerative diseases. The current study characterizes the aggregation pathway of two tau protein constructs that have been recently demonstrated to form Alzheimer's (AD) fibril structures with divalent ions and chronic traumatic encephalopathy (CTE) fibril structures with monovalent ions. The results highlight the involvement of identical residues in both the primary and secondary processes of both AD and CTE fibril propagation. Nuclear magnetic resonance relaxation experiments reveal increased flexibility of the motifs 321KCGS within R3 and 364PGGGN within R4 in the presence of MgCl2/NaCl, correlating with faster aggregation kinetics and indicating efficient primary nucleation. Notably, the seeded aggregation kinetics of the tau monomers in the presence and absence of metal ions are strikingly different. This correlates with the overall sign of the 15N-ΔR2 profile specifying the dominant mechanism involved in the process of aggregation.
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Affiliation(s)
- Arshad Abdul Vahid
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM) Vithura, Thiruvananthapuram695551,India
| | | | - Allwin Ebenezer Sahayaraj
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM) Vithura, Thiruvananthapuram695551,India
| | - Ann Teres Babu
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM) Vithura, Thiruvananthapuram695551,India
| | - Safwa T Kizhakkeduth
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM) Vithura, Thiruvananthapuram695551,India
| | - Vinesh Vijayan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM) Vithura, Thiruvananthapuram695551,India
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3
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El Mammeri N, Duan P, Dregni AJ, Hong M. Amyloid fibril structures of tau: Conformational plasticity of the second microtubule-binding repeat. SCIENCE ADVANCES 2023; 9:eadh4731. [PMID: 37450599 PMCID: PMC10348678 DOI: 10.1126/sciadv.adh4731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/14/2023] [Indexed: 07/18/2023]
Abstract
The intrinsically disordered protein tau associates with microtubules in neurons but aggregates into cross-β amyloid fibrils that propagate in neurodegenerative brains. Different tauopathies have different structures for the rigid fibril core. To understand the molecular basis of tau assembly into different polymorphs, here we use solid-state nuclear magnetic resonance (NMR) spectroscopy to determine the structure of a tau protein that includes all microtubule-binding repeats and a proline-rich domain. This P2R tau assembles into well-ordered filaments when induced by heparin. Two- and three-dimensional NMR spectra indicate that R2 and R3 repeats constitute the rigid β-sheet core of the fibril. Unexpectedly, the amino-terminal half of R2 forms a β-arch at ambient temperature (24°C) but a continuous β-strand at 12°C, which dimerizes with the R2 of another protofilament. This temperature-dependent structure indicates that R2 is conformationally more plastic than the R3 domain. The distinct conformational stabilities of different microtubule-binding repeats give insight into the energy landscape of tau fibril formation.
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Affiliation(s)
- Nadia El Mammeri
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, USA
| | - Pu Duan
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, USA
| | - Aurelio J. Dregni
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, USA
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, USA
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4
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El Mammeri N, Gampp O, Duan P, Hong M. Membrane-induced tau amyloid fibrils. Commun Biol 2023; 6:467. [PMID: 37117483 PMCID: PMC10147698 DOI: 10.1038/s42003-023-04847-6] [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: 04/03/2023] [Accepted: 04/17/2023] [Indexed: 04/30/2023] Open
Abstract
The intrinsically disordered protein tau aggregates into β-sheet amyloid fibrils that spread in human brains afflicted with Alzheimer's disease and other neurodegenerative diseases. Tau interaction with lipid membranes might play a role in the formation and spreading of these pathological aggregates. Here we investigate the conformation and assembly of membrane-induced tau aggregates using solid-state NMR and transmission electron microscopy. A tau construct that encompasses the microtubule-binding repeats and a proline-rich domain is reconstituted into cholesterol-containing phospholipid membranes. 2D 13C-13C correlation spectra indicate that tau converted from a random coil to a β-sheet conformation over weeks. Small unilamellar vesicles (SUVs) cause different equilibrium conformations from large unilamellar vesicles (LUVs) and multilamellar vesicles (MLVs). Importantly, SUV-bound tau developed long fibrils that exhibit the characteristic β-sheet chemical shifts of Tyr310 in heparin-fibrillized tau. In comparison, LUVs and MLVs do not induce fibrils but cause different β-sheet aggregates. Lipid-protein correlation spectra indicate that these tau aggregates reside at the membrane-water interface, without inserting into the middle of the lipid bilayer. Removal of cholesterol from the SUVs abolished the fibrils, indicating that both membrane curvature and cholesterol are required for tau fibril formation. These results have implications for how lipid membranes might nucleate tau aggregates.
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Affiliation(s)
- Nadia El Mammeri
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Olivia Gampp
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Pu Duan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.
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5
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Tau-aggregation inhibitors derived from Streptomyces tendae MCCC 1A01534 protect HT22 cells against okadaic acid-induced damage. Int J Biol Macromol 2023; 231:123170. [PMID: 36621732 DOI: 10.1016/j.ijbiomac.2023.123170] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 12/20/2022] [Accepted: 01/03/2023] [Indexed: 01/07/2023]
Abstract
Alzheimer's disease (AD) is an age-related neurodegenerative disease characterized by tau aggregating into neurofibrillary tangles. Targeting tau aggregation is one of the most critical strategies for AD treatment and prevention. Herein, a high-throughput screening of tau-aggregation inhibitors was performed by thioflavin T (ThT) fluorescence assay and tauR3 peptides. According to bioactivity-guided isolation, homoprejadomycin (1) was obtained from the marine bacterium Streptomyces tendae MCCC 1A01534. Two new stable derivatives, 2 and 3, were yielded in a one-step reaction. By ThT assay, transmission electron microscopy, and circular dichroism, we demonstrated that the angucyclinones 2 and 3 inhibited tau aggregation and disaggregated tau fibrils. In the presence of 2, native tauR3 peptides maintained the disorder conformation, whereas the tauR3 aggregates reduced β-sheet structures. And compound 2 was confirmed to inhibit the aggregation of full-length 2N4R tau protein. Furthermore, 2 with low cytotoxicity protected HT22 cells from okadaic acid-induced damage by suppressing tau aggregates. These results indicated that 2 was a promising lead structure with tau therapeutic potency for AD treatment.
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Al-Hilaly YK, Hurt C, Rickard JE, Harrington CR, Storey JMD, Wischik CM, Serpell LC, Siemer AB. Solid-state NMR of paired helical filaments formed by the core tau fragment tau(297-391). Front Neurosci 2022; 16:988074. [PMID: 36570831 PMCID: PMC9774000 DOI: 10.3389/fnins.2022.988074] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 11/23/2022] [Indexed: 12/13/2022] Open
Abstract
Aggregation of the tau protein into fibrillar cross-β aggregates is a hallmark of Alzheimer's diseases (AD) and many other neurodegenerative tauopathies. Recently, several core structures of patient-derived tau paired helical filaments (PHFs) have been solved revealing a structural variability that often correlates with a specific tauopathy. To further characterize the dynamics of these fibril cores, to screen for strain-specific small molecules as potential biomarkers and therapeutics, and to develop strain-specific antibodies, recombinant in-vitro models of tau filaments are needed. We recently showed that a 95-residue fragment of tau (from residue 297 to 391), termed dGAE, forms filaments in vitro in the absence of polyanionic co-factors often used for in vitro aggregation of full-length tau. Tau(297-391) was identified as the proteolytic resistant core of tau PHFs and overlaps with the structures characterized by cryo-electron microscopy in ex vivo PHFs, making it a promising model for the study of AD tau filaments in vitro. In the present study, we used solid-state NMR to characterize tau(297-391) filaments and show that such filaments assembled under non-reducing conditions are more dynamic and less ordered than those made in the presence of the reducing agent DTT. We further report the resonance assignment of tau(297-391)+DTT filaments and compare it to existing core structures of tau.
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Affiliation(s)
- Youssra K. Al-Hilaly
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, United Kingdom,Chemistry Department, College of Science, Mustansiriyah University, Baghdad, Iraq
| | - Connor Hurt
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Janet E. Rickard
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Charles R. Harrington
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,TauRx Therapeutics Ltd., Aberdeen, United Kingdom
| | - John M. D. Storey
- TauRx Therapeutics Ltd., Aberdeen, United Kingdom,Department of Chemistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Claude M. Wischik
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,TauRx Therapeutics Ltd., Aberdeen, United Kingdom
| | - Louise C. Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, United Kingdom
| | - Ansgar B. Siemer
- Department of Physiology and Neuroscience, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States,*Correspondence: Ansgar B. Siemer,
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7
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Shapeshifting tau: from intrinsically disordered to paired-helical filaments. Essays Biochem 2022; 66:1001-1011. [PMID: 36373666 PMCID: PMC9760425 DOI: 10.1042/ebc20220150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/25/2022] [Accepted: 10/26/2022] [Indexed: 11/16/2022]
Abstract
Tau is an intrinsically disordered protein that has the ability to self-assemble to form paired helical and straight filaments in Alzheimer's disease, as well as the ability to form additional distinct tau filaments in other tauopathies. In the presence of microtubules, tau forms an elongated form associated with tubulin dimers via a series of imperfect repeats known as the microtubule binding repeats. Tau has recently been identified to have the ability to phase separate in vitro and in cells. The ability of tau to adopt a wide variety of conformations appears fundamental both to its biological function and also its association with neurodegenerative diseases. The recently highlighted involvement of low-complexity domains in liquid-liquid phase separation provides a critical link between the soluble function and the insoluble dysfunctional properties of tau.
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8
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Matlahov I, Boatz JC, C.A. van der Wel P. Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils. J Struct Biol X 2022; 6:100077. [PMID: 36419510 PMCID: PMC9677204 DOI: 10.1016/j.yjsbx.2022.100077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 09/20/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022] Open
Abstract
Mutant huntingtin exon 1 fibrils feature a broad range of molecular dynamics. Molecular motion is coupled to water dynamics outside the fiber core. Dynamics-based spectral editing ssNMR reveals mobile non-core residues. Intermediate-motion selection via dipolar dephasing of rigid sites. Semi-mobile glutamines outside the fiber core observed and identified.
Many amyloid-forming proteins, which are normally intrinsically disordered, undergo a disorder-to-order transition to form fibrils with a rigid β-sheet core flanked by disordered domains. Solid-state NMR (ssNMR) and cryogenic electron microscopy (cryoEM) excel at resolving the rigid structures within amyloid cores but studying the dynamically disordered domains remains challenging. This challenge is exemplified by mutant huntingtin exon 1 (HttEx1), which self-assembles into pathogenic neuronal inclusions in Huntington disease (HD). The mutant protein’s expanded polyglutamine (polyQ) segment forms a fibril core that is rigid and sequestered from the solvent. Beyond the core, solvent-exposed surface residues mediate biological interactions and other properties of fibril polymorphs. Here we deploy magic angle spinning ssNMR experiments to probe for semi-rigid residues proximal to the fibril core and examine how solvent dynamics impact the fibrils’ segmental dynamics. Dynamic spectral editing (DYSE) 2D ssNMR based on a combination of cross-polarization (CP) ssNMR with selective dipolar dephasing reveals the weak signals of solvent-mobilized glutamine residues, while suppressing the normally strong background of rigid core signals. This type of ‘intermediate motion selection’ (IMS) experiment based on cross-polarization (CP) ssNMR, is complementary to INEPT- and CP-based measurements that highlight highly flexible or highly rigid protein segments, respectively. Integration of the IMS-DYSE element in standard CP-based ssNMR experiments permits the observation of semi-rigid residues in a variety of contexts, including in membrane proteins and protein complexes. We discuss the relevance of semi-rigid solvent-facing residues outside the fibril core to the latter’s detection with specific dyes and positron emission tomography tracers.
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9
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Zeng Z, Fichou Y, Vigers M, Tsay K, Han S. Illuminating the Structural Basis of Tau Aggregation by Intramolecular Distance Tracking: A Perspective on Methods. J Phys Chem B 2022; 126:6384-6395. [PMID: 35994024 DOI: 10.1021/acs.jpcb.2c02022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The aggregation of the tau protein is central to several neurodegenerative diseases, collectively known as tauopathies. High-resolution views of tau tangles accumulated under pathological conditions in post-mortem brains have been revealed recently by cryogenic electron microscopy. One of the striking discoveries was that fibril folds are unique to and homogeneous within one disease family, but typically different between different tauopathies. It is widely believed that seeded aggregation can achieve structural propagation of tau fibrils and generate pathological fibril structures. However, direct molecular level measurement of structural evolution during aggregation is missing. Here, we discuss our perspective on the biophysical approaches that can contribute to the ongoing debate regarding the prion-like propagation of tau and the role of cofactors. We discuss the unique potential of double electron-electron resonance (DEER)-based intramolecular distance measurement, sensitive to two to several nanometers distances. DEER can track the structural evolution of tau along the course of aggregation from the completely disordered state, to partially ordered and highly ordered fibril states, and has the potential to be a key tool to elucidate the disease-specific tau aggregation pathways.
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Affiliation(s)
- Zhikai Zeng
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Yann Fichou
- CNRS, Chemistry and Biology of Membranes and Nanoobjects (CBMN) UMR 5348, Institut Europeen de Chimie et Biologie (IECB), University of Bordeaux, 33600 Pessac, France
| | - Michael Vigers
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Karen Tsay
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States.,Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
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10
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Hu J, Zhao Y, Li Y. Rationally designed amyloid inhibitors based on amyloid-related structural studies. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.06.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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11
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Landrieu I, Dupré E, Sinnaeve D, El Hajjar L, Smet-Nocca C. Deciphering the Structure and Formation of Amyloids in Neurodegenerative Diseases With Chemical Biology Tools. Front Chem 2022; 10:886382. [PMID: 35646824 PMCID: PMC9133342 DOI: 10.3389/fchem.2022.886382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/20/2022] [Indexed: 11/24/2022] Open
Abstract
Protein aggregation into highly ordered, regularly repeated cross-β sheet structures called amyloid fibrils is closely associated to human disorders such as neurodegenerative diseases including Alzheimer's and Parkinson's diseases, or systemic diseases like type II diabetes. Yet, in some cases, such as the HET-s prion, amyloids have biological functions. High-resolution structures of amyloids fibrils from cryo-electron microscopy have very recently highlighted their ultrastructural organization and polymorphisms. However, the molecular mechanisms and the role of co-factors (posttranslational modifications, non-proteinaceous components and other proteins) acting on the fibril formation are still poorly understood. Whether amyloid fibrils play a toxic or protective role in the pathogenesis of neurodegenerative diseases remains to be elucidated. Furthermore, such aberrant protein-protein interactions challenge the search of small-molecule drugs or immunotherapy approaches targeting amyloid formation. In this review, we describe how chemical biology tools contribute to new insights on the mode of action of amyloidogenic proteins and peptides, defining their structural signature and aggregation pathways by capturing their molecular details and conformational heterogeneity. Challenging the imagination of scientists, this constantly expanding field provides crucial tools to unravel mechanistic detail of amyloid formation such as semisynthetic proteins and small-molecule sensors of conformational changes and/or aggregation. Protein engineering methods and bioorthogonal chemistry for the introduction of protein chemical modifications are additional fruitful strategies to tackle the challenge of understanding amyloid formation.
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Affiliation(s)
- Isabelle Landrieu
- University Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, Lille, France
- CNRS EMR9002 Integrative Structural Biology, Lille, France
| | - Elian Dupré
- University Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, Lille, France
- CNRS EMR9002 Integrative Structural Biology, Lille, France
| | - Davy Sinnaeve
- University Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, Lille, France
- CNRS EMR9002 Integrative Structural Biology, Lille, France
| | - Léa El Hajjar
- University Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, Lille, France
- CNRS EMR9002 Integrative Structural Biology, Lille, France
| | - Caroline Smet-Nocca
- University Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, Lille, France
- CNRS EMR9002 Integrative Structural Biology, Lille, France
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Kitoka K, Skrabana R, Gasparik N, Hritz J, Jaudzems K. NMR Studies of Tau Protein in Tauopathies. Front Mol Biosci 2021; 8:761227. [PMID: 34859051 PMCID: PMC8632555 DOI: 10.3389/fmolb.2021.761227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/25/2021] [Indexed: 11/13/2022] Open
Abstract
Tauopathies, including Alzheimer's disease (AD), are the most troublesome of all age-related chronic conditions, as there are no well-established disease-modifying therapies for their prevention and treatment. Spatio-temporal distribution of tau protein pathology correlates with cognitive decline and severity of the disease, therefore, tau protein has become an appealing target for therapy. Current knowledge of the pathological effects and significance of specific species in the tau aggregation pathway is incomplete although more and more structural and mechanistic insights are being gained using biophysical techniques. Here, we review the application of NMR to structural studies of various tau forms that appear in its aggregation process, focusing on results obtained from solid-state NMR. Furthermore, we discuss implications from these studies and their prospective contribution to the development of new tauopathy therapies.
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Affiliation(s)
- Kristine Kitoka
- Laboratory of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, Latvia
| | - Rostislav Skrabana
- Institute of Neuroimmunology, Slovak Academy of Sciences, Bratislava, Slovakia
- AXON Neuroscience R&D Services SE, Bratislava, Slovakia
| | - Norbert Gasparik
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Faculty of Science, National Centre for Biomolecular Research, Masaryk University, Brno, Czech Republic
| | - Jozef Hritz
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Kristaps Jaudzems
- Laboratory of Physical Organic Chemistry, Latvian Institute of Organic Synthesis, Riga, Latvia
- Faculty of Chemistry, University of Latvia, Riga, Latvia
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13
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Target-binding behavior of IDPs via pre-structured motifs. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 183:187-247. [PMID: 34656329 DOI: 10.1016/bs.pmbts.2021.07.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Pre-Structured Motifs (PreSMos) are transient secondary structures observed in many intrinsically disordered proteins (IDPs) and serve as protein target-binding hot spots. The prefix "pre" highlights that PreSMos exist a priori in the target-unbound state of IDPs as the active pockets of globular proteins pre-exist before target binding. Therefore, a PreSMo is an "active site" of an IDP; it is not a spatial pocket, but rather a secondary structural motif. The classical and perhaps the most effective approach to understand the function of a protein has been to determine and investigate its structure. Ironically or by definition IDPs do not possess structure (here structure refers to tertiary structure only). Are IDPs then entirely structureless? The PreSMos provide us with an atomic-resolution answer to this question. For target binding, IDPs do not rely on the spatial pockets afforded by tertiary or higher structures. Instead, they utilize the PreSMos possessing particular conformations that highly presage the target-bound conformations. PreSMos are recognized or captured by targets via conformational selection (CS) before their conformations eventually become stabilized via structural induction into more ordered bound structures. Using PreSMos, a number of, if not all, IDPs can bind targets following a sequential pathway of CS followed by an induced fit (IF). This chapter presents several important PreSMos implicated in cancers, neurodegenerative diseases, and other diseases along with discussions on their conformational details that mediate target binding, a structural rationale for unstructured proteins.
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14
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Phyo P, Zhao X, Templeton AC, Xu W, Cheung JK, Su Y. Understanding molecular mechanisms of biologics drug delivery and stability from NMR spectroscopy. Adv Drug Deliv Rev 2021; 174:1-29. [PMID: 33609600 DOI: 10.1016/j.addr.2021.02.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/20/2021] [Accepted: 02/07/2021] [Indexed: 02/06/2023]
Abstract
Protein therapeutics carry inherent limitations of membrane impermeability and structural instability, despite their predominant role in the modern pharmaceutical market. Effective formulations are needed to overcome physiological and physicochemical barriers, respectively, for improving bioavailability and stability. Knowledge of membrane affinity, cellular internalization, encapsulation, and release of drug-loaded carrier vehicles uncover the structural basis for designing and optimizing biopharmaceuticals with enhanced delivery efficiency and therapeutic efficacy. Understanding stabilizing and destabilizing interactions between protein drugs and formulation excipients provide fundamental mechanisms for ensuring the stability and quality of biological products. This article reviews the molecular studies of biologics using solution and solid-state NMR spectroscopy on structural attributes pivotal to drug delivery and stability. In-depth investigation of the structure-function relationship of drug delivery systems based on cell-penetrating peptides, lipid nanoparticles and polymeric colloidal, and biophysical and biochemical stability of peptide, protein, monoclonal antibody, and vaccine, as the integrative efforts on drug product design, will be elaborated.
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Affiliation(s)
- Pyae Phyo
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Xi Zhao
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Allen C Templeton
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Wei Xu
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Jason K Cheung
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Yongchao Su
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States.
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15
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Dregni AJ, Wang HK, Wu H, Duan P, Jin J, DeGrado WF, Hong M. Inclusion of the C-Terminal Domain in the β-Sheet Core of Heparin-Fibrillized Three-Repeat Tau Protein Revealed by Solid-State Nuclear Magnetic Resonance Spectroscopy. J Am Chem Soc 2021; 143:7839-7851. [PMID: 33983722 PMCID: PMC8283780 DOI: 10.1021/jacs.1c03314] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Many neurodegenerative diseases such as Alzheimer's disease are characterized by pathological β-sheet filaments of the tau protein, which spread in a prion-like manner in patient brains. To date, high-resolution structures of tau filaments obtained from patient brains show that the β-sheet core only includes portions of the microtubule-binding repeat domains and excludes the C-terminal residues, indicating that the C-terminus is dynamically disordered. Here, we use solid-state NMR spectroscopy to identify the β-sheet core of full-length 0N3R tau fibrillized using heparin. Assignment of 13C and 15N chemical shifts of the rigid core of the protein revealed a single predominant β-sheet conformation, which spans not only the R3, R4, R' repeats but also the entire C-terminal domain (CT) of the protein. This massive β-sheet core qualitatively differs from all other tau fibril structures known to date. Using long-range correlation NMR experiments, we found that the R3 and R4 repeats form a β-arch, similar to that seen in some of the brain-derived tau fibrils, but the R1 and R3 domains additionally stack against the CT, reminiscent of previously reported transient interactions of the CT with the microtubule-binding repeats. This expanded β-sheet core structure suggests that the CT may have a protective effect against the formation of pathological tau fibrils by shielding the amyloidogenic R3 and R4 domains, preventing side-on nucleation. Truncation and post-translational modification of the CT in vivo may thus play an important role in the progression of tauopathies.
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Affiliation(s)
- Aurelio J. Dregni
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Harrison K. Wang
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Haifan Wu
- Department of Pharmaceutical Chemistry, 555 Mission Bay Blvd. South, CVRB, Room 452V, University of California, San Francisco, CA 94158-9001
| | - Pu Duan
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Jia Jin
- Department of Pharmaceutical Chemistry, 555 Mission Bay Blvd. South, CVRB, Room 452V, University of California, San Francisco, CA 94158-9001
| | - William F. DeGrado
- Department of Pharmaceutical Chemistry, 555 Mission Bay Blvd. South, CVRB, Room 452V, University of California, San Francisco, CA 94158-9001
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
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16
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Jayan P, Vahid AA, Kizhakkeduth ST, Muhammed SOH, Shibina AB, Vijayan V. Direct Observation of the Self-Aggregation of R3R4 Bi-repeat of Tau Protein. Chembiochem 2021; 22:2093-2097. [PMID: 33826208 DOI: 10.1002/cbic.202100013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/04/2021] [Indexed: 11/06/2022]
Abstract
Different cryo-EM derived atomic models of in vivo tau filaments from patients with tauopathies consisted of R3 and R4 repeats of the microtubule-binding domain. In comparison, only the R3 repeat forms the core of the heparin-induced fibrils of the three repeat tau isoforms. For developing therapeutics, it is desirable to have an in vitro tau aggregation system producing fibrils corresponding to the disease morphology. Here we report the self-aggregation of truncated tau segment R3R4 peptide without requiring heparin for aggregation induction. We used NMR spectroscopy and other biophysical methods to monitor the self-aggregation of R3R4. We identified the hexapeptide region in R3 and β-turn region in R4 as the aggregation initiating region of the protein. The solid-state NMR of self-aggregated R3R4 fibrils demonstrated that in addition to R3 residues, residues of R4 were also part of the fibril filaments. The presence of both R3 and R4 residues in the aggregation process and the core of fibril filaments suggest that the aggregation of R3R4 might resemble the in vivo aggregation process.
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Affiliation(s)
- Parvathy Jayan
- School of Chemistry, IISER Thiruvananthapuram, Maruthamala P.O, Thiruvananthapuram, Kerala, India
| | - Arshad A Vahid
- School of Chemistry, IISER Thiruvananthapuram, Maruthamala P.O, Thiruvananthapuram, Kerala, India
| | - Safwa T Kizhakkeduth
- School of Chemistry, IISER Thiruvananthapuram, Maruthamala P.O, Thiruvananthapuram, Kerala, India
| | - Shafeek O H Muhammed
- School of Chemistry, IISER Thiruvananthapuram, Maruthamala P.O, Thiruvananthapuram, Kerala, India
| | - Ajmala B Shibina
- School of Chemistry, IISER Thiruvananthapuram, Maruthamala P.O, Thiruvananthapuram, Kerala, India
| | - Vinesh Vijayan
- School of Chemistry, IISER Thiruvananthapuram, Maruthamala P.O, Thiruvananthapuram, Kerala, India
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17
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Zeng Y, Yang J, Zhang B, Gao M, Su Z, Huang Y. The structure and phase of tau: from monomer to amyloid filament. Cell Mol Life Sci 2021; 78:1873-1886. [PMID: 33078207 PMCID: PMC11073437 DOI: 10.1007/s00018-020-03681-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 09/20/2020] [Accepted: 10/07/2020] [Indexed: 12/12/2022]
Abstract
Tau is a microtubule-associated protein involved in regulation of assembly and spatial organization of microtubule in neurons. However, in pathological conditions, tau monomers assemble into amyloid filaments characterized by the cross-β structures in a number of neurodegenerative diseases known as tauopathies. In this review, we summarize recent progression on the characterization of structures of tau monomer and filament, as well as the dynamic liquid droplet assembly. Our aim is to reveal how post-translational modifications, amino acid mutations, and interacting molecules modulate the conformational ensemble of tau monomer, and how they accelerate or inhibit tau assembly into aggregates. Structure-based aggregation inhibitor design is also discussed in the context of dynamics and heterogeneity of tau structures.
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Affiliation(s)
- Yifan Zeng
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan, China
- Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, China
| | - Jing Yang
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan, China
- Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, China
| | - Bailing Zhang
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan, China
- Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, China
| | - Meng Gao
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan, China
- Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, China
| | - Zhengding Su
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan, China
- Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, China
| | - Yongqi Huang
- Key Laboratory of Industrial Fermentation (Ministry of Education), Hubei University of Technology, Wuhan, China.
- Hubei Key Laboratory of Industrial Microbiology, Hubei University of Technology, Wuhan, China.
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18
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Yang J, Agnihotri MV, Huseby CJ, Kuret J, Singer SJ. A theoretical study of polymorphism in VQIVYK fibrils. Biophys J 2021; 120:1396-1416. [PMID: 33571490 DOI: 10.1016/j.bpj.2021.01.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 01/07/2021] [Accepted: 01/11/2021] [Indexed: 02/06/2023] Open
Abstract
The VQIVYK fragment from the Tau protein, also known as PHF6, is essential for aggregation of Tau into neurofibrillary lesions associated with neurodegenerative diseases. VQIVYK itself forms amyloid fibrils composed of paired β-sheets. Therefore, the full Tau protein and VQIVYK fibrils have been intensively investigated. A central issue in these studies is polymorphism, the ability of a protein to fold into more than one structure. Using all-atom molecular simulations, we generate five stable polymorphs of VQIVYK fibrils, establish their relative free energy with umbrella sampling methods, and identify the side chain interactions that provide stability. The two most stable polymorphs, which have nearly equal free energy, are formed by interdigitation of the mostly hydrophobic VIY "face" sides of the β-sheets. Another stable polymorph is formed by interdigitation of the QVK "back" sides. When we turn to examine structures from cryo-electron microscopy experiments on Tau filaments taken from diseased patients or generated in vitro, we find that the pattern of side chain interactions found in the two most stable face-to-face as well as the back-to-back polymorphs are recapitulated in amyloid structures of the full protein. Thus, our studies suggest that the interactions stabilizing PHF6 fibrils explain the amyloidogenicity of the VQIVYK motif within the full Tau protein and provide justification for the use of VQIVYK fibrils as a test bed for the design of molecules that identify or inhibit amyloid structures.
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Affiliation(s)
- Jaehoon Yang
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio
| | - Mithila V Agnihotri
- Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, Ohio
| | - Carol J Huseby
- Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, Ohio
| | - Jeff Kuret
- Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, Ohio; Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, Ohio.
| | - Sherwin J Singer
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio; Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, Ohio.
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19
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Andronesi OC, Nicholson K, Jafari-Khouzani K, Bogner W, Wang J, Chan J, Macklin EA, Levine-Weinberg M, Breen C, Schwarzschild MA, Cudkowicz M, Rosen BR, Paganoni S, Ratai EM. Imaging Neurochemistry and Brain Structure Tracks Clinical Decline and Mechanisms of ALS in Patients. Front Neurol 2020; 11:590573. [PMID: 33343494 PMCID: PMC7744722 DOI: 10.3389/fneur.2020.590573] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 11/03/2020] [Indexed: 12/27/2022] Open
Abstract
Background: Oxidative stress and protein aggregation are key mechanisms in amyotrophic lateral sclerosis (ALS) disease. Reduced glutathione (GSH) is the most important intracellular antioxidant that protects neurons from reactive oxygen species. We hypothesized that levels of GSH measured by MR spectroscopic imaging (MRSI) in the motor cortex and corticospinal tract are linked to clinical trajectory of ALS patients. Objectives: Investigate the value of GSH imaging to probe clinical decline of ALS patients in combination with other neurochemical and structural parameters. Methods: Twenty-four ALS patients were imaged at 3 T with an advanced MR protocol. Mapping GSH levels in the brain is challenging, and for this purpose, we used an optimized spectral-edited 3D MRSI sequence with real-time motion and field correction to image glutathione and other brain metabolites. In addition, our imaging protocol included (i) an adiabatic T1ρ sequence to image macromolecular fraction of brain parenchyma, (ii) diffusion tensor imaging (DTI) for white matter tractography, and (iii) high-resolution anatomical imaging. Results: We found GSH in motor cortex (r = −0.431, p = 0.04) and corticospinal tract (r = −0.497, p = 0.016) inversely correlated with time between diagnosis and imaging. N-Acetyl-aspartate (NAA) in motor cortex inversely correlated (r = −0.416, p = 0.049), while mean water diffusivity (r = 0.437, p = 0.033) and T1ρ (r = 0.482, p = 0.019) positively correlated with disease progression measured by imputed change in revised ALS Functional Rating Scale. There is more decrease in the motor cortex than in the white matter for GSH compared to NAA, glutamate, and glutamine. Conclusions: Our study suggests that a panel of biochemical and structural imaging biomarkers defines a brain endophenotype, which can be used to time biological events and clinical progression in ALS patients. Such a quantitative brain endophenotype may stratify ALS patients into more homogeneous groups for therapeutic interventions compared to clinical criteria.
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Affiliation(s)
- Ovidiu C Andronesi
- Department of Radiology, A. A. Martinos Center for Biomedical Imaging, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States
| | - Katharine Nicholson
- Neurological Clinical Research Institute (NCRI), Massachusetts General Hospital, Boston, MA, United States
| | - Kourosh Jafari-Khouzani
- Department of Radiology, A. A. Martinos Center for Biomedical Imaging, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States
| | - Wolfgang Bogner
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Jing Wang
- Department of Radiology, A. A. Martinos Center for Biomedical Imaging, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States.,Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - James Chan
- Biostatistics Center, Massachusetts General Hospital, Boston, MA, United States
| | - Eric A Macklin
- Biostatistics Center, Massachusetts General Hospital, Boston, MA, United States
| | - Mark Levine-Weinberg
- Neurological Clinical Research Institute (NCRI), Massachusetts General Hospital, Boston, MA, United States
| | - Christopher Breen
- Neurological Clinical Research Institute (NCRI), Massachusetts General Hospital, Boston, MA, United States
| | | | - Merit Cudkowicz
- Neurological Clinical Research Institute (NCRI), Massachusetts General Hospital, Boston, MA, United States
| | - Bruce R Rosen
- Department of Radiology, A. A. Martinos Center for Biomedical Imaging, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States
| | - Sabrina Paganoni
- Neurological Clinical Research Institute (NCRI), Massachusetts General Hospital, Boston, MA, United States.,Spaulding Rehabilitation Hospital, Boston, MA, United States
| | - Eva-Maria Ratai
- Department of Radiology, A. A. Martinos Center for Biomedical Imaging, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States
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20
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Solid-state NMR investigation of the involvement of the P2 region in tau amyloid fibrils. Sci Rep 2020; 10:21210. [PMID: 33273615 PMCID: PMC7712923 DOI: 10.1038/s41598-020-78161-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/20/2020] [Indexed: 11/08/2022] Open
Abstract
The aggregation of hyperphosphorylated tau into amyloid fibrils is closely linked to the progression of Alzheimer's disease. To gain insight into the link between amyloid structure and disease, the three-dimensional structure of tau fibrils has been studied using solid-state NMR (ssNMR) and cryogenic electron microscopy (cryo-EM). The proline-rich region of tau remains poorly defined in the context of tau amyloid structures, despite the clustering of several phosphorylation sites, which have been associated with Alzheimer's disease. In order to gain insight into the contribution of the proline-rich region P2 of tau to amyloid fibrils, we studied in vitro aggregated amyloid fibrils of tau constructs, which contain both the proline-rich region P2 and the pseudo-repeats. Using ssNMR we show that the sequence [Formula: see text], the most hydrophobic patch within the P2 region, loses its flexibility upon formation of amyloid fibrils. The data suggest a contribution of the P2 region to tau amyloid fibril formation, which might account for some of the unassigned electron density in cryo-EM studies of tau fibrils and could be modulated by tau phosphorylation at the disease-associated AT180 epitope T231/S235.
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21
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Enhanced Water Solubility and Oral Bioavailability of Paclitaxel Crystal Powders through an Innovative Antisolvent Precipitation Process: Antisolvent Crystallization Using Ionic Liquids as Solvent. Pharmaceutics 2020; 12:pharmaceutics12111008. [PMID: 33105832 PMCID: PMC7690586 DOI: 10.3390/pharmaceutics12111008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/14/2020] [Accepted: 10/18/2020] [Indexed: 11/29/2022] Open
Abstract
Paclitaxel (PTX) is a poor water-soluble antineoplastic drug with significant antitumor activity. However, its low bioavailability is a major obstacle for its biomedical applications. Thus, this experiment is designed to prepare PTX crystal powders through an antisolvent precipitation process using 1-hexyl-3-methylimidazolium bromide (HMImBr) as solvent and water as an antisolvent. The factors influencing saturation solubility of PTX crystal powders in water in water were optimized using a single-factor design. The optimum conditions for the antisolvent precipitation process were as follows: 50 mg/mL concentration of the PTX solution, 25 °C temperature, and 1:7 solvent-to-antisolvent ratio. The PTX crystal powders were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, high-performance liquid chromatography–mass spectrometry, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Raman spectroscopy, solid-state nuclear magnetic resonance, and dissolution and oral bioavailability studies. Results showed that the chemical structure of PTX crystal powders were unchanged; however, precipitation of the crystalline structure changed. The dissolution test showed that the dissolution rate and solubility of PTX crystal powders were nearly 3.21-folds higher compared to raw PTX in water, and 1.27 times higher in artificial gastric juice. Meanwhile, the bioavailability of PTX crystal increased 10.88 times than raw PTX. These results suggested that PTX crystal powders might have potential value to become a new oral PTX formulation with high bioavailability.
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22
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Townsend D, Fullwood NJ, Yates EA, Middleton DA. Aggregation Kinetics and Filament Structure of a Tau Fragment Are Influenced by the Sulfation Pattern of the Cofactor Heparin. Biochemistry 2020; 59:4003-4014. [PMID: 32954725 PMCID: PMC7584336 DOI: 10.1021/acs.biochem.0c00443] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 09/11/2020] [Indexed: 01/16/2023]
Abstract
A pathological signature of Alzheimer's disease (AD) is the formation of neurofibrillary tangles comprising filamentous aggregates of the microtubule associated protein tau. Tau self-assembly is accelerated by polyanions including heparin, an analogue of heparan sulfate. Tau filaments colocalize with heparan sulfate proteoglycans (HSPGs) in vivo, and HSPGs may also assist the transcellular propagation of tau aggregates. Here, we investigate the role of the sulfate moieties of heparin in the aggregation of a recombinant tau fragment Δtau187, comprising residues 255-441 of the C-terminal microtubule-binding domain. The effects that the selective removal of the N-, 2-O-, and 6-O-sulfate groups from heparin have on the kinetics of tau aggregation, aggregate morphology, and protein structure and dynamics were examined. Aggregation kinetics monitored by thioflavin T (ThT) fluorescence revealed that aggregation is considerably slower in the presence of 2-O-desulfated heparin than with N- or 6-O-desulfated heparin. Transmission electron microscopy revealed that tau filaments induced by 2-O-desulfated heparin were more slender than filaments formed in the presence of intact heparin or 6-O-desulfated heparin. The 2-O-desulfated heparin-induced filaments had more extensive regions of flexibility than the other filaments, according to circular dichroism and solid-state NMR spectroscopy. These results indicate that the sulfation pattern of heparin regulates tau aggregation, not purely though electrostatic forces but also through conformational perturbations of heparin when the 2-O-sulfate is removed. These findings may have implications for the progression of AD, as the sulfation pattern of GAGs is known to change during the aging process, which is the main risk factor for the disease.
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Affiliation(s)
- David Townsend
- Department
of Chemistry, University of Lancaster, Lancaster LA1 4YB, U.K.
| | - Nigel J. Fullwood
- Division
of Biomedical and Life Sciences, University
of Lancaster, Lancaster LA1 4YG, U.K.
| | - Edwin A. Yates
- Department
of Biochemistry and Systems Biology, Institute of Systems, Molecular
and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K.
| | - David A. Middleton
- Department
of Chemistry, University of Lancaster, Lancaster LA1 4YB, U.K.
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23
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Fields CR, Dicke SS, Petti MK, Zanni MT, Lomont JP. A Different hIAPP Polymorph Is Observed in Human Serum Than in Aqueous Buffer: Demonstration of a New Method for Studying Amyloid Fibril Structure Using Infrared Spectroscopy. J Phys Chem Lett 2020; 11:6382-6388. [PMID: 32706257 PMCID: PMC7968077 DOI: 10.1021/acs.jpclett.0c01345] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
There is enormous interest in measuring amyloid fibril structures, but most structural studies measure fibril formation in vitro using aqueous buffer. Ideally, one would like to measure fibril structure and mechanism under more physiological conditions. Toward this end, we have developed a method for studying amyloid fibril structure in human serum. Our approach uses isotope labeling, antibody depletion of the most abundant proteins (albumin and IgG), and infrared spectroscopy to measure aggregation in human serum with reduced protein content. Reducing the nonamyloid protein content enables the measurements by decreasing background signals but retains the full composition of salts, sugars, metal ions, etc. that are naturally present but usually missing from in vitro studies. We demonstrate the method by measuring the two-dimensional infrared (2D IR) spectra of isotopically labeled human islet amyloid polypeptide (hIAPP or amylin). We find that the fibril structure of hIAPP formed in serum differs from that formed via aggregation in aqueous buffer at residues Gly24 and Ala25, which reside in the putative "amyloidogenic core" or FGAIL region of the sequence. The spectra are consistent with extended parallel stacks of strands consistent with β-sheet-like structure, rather than a partially disordered loop that forms in aqueous buffer. These experiments provide a new method for using infrared spectroscopy to monitor the structure of proteins under physiological conditions and reveal the formation of a significantly different polymorph structure in the most important region of hIAPP.
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Affiliation(s)
- Caitlyn R Fields
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Sidney S Dicke
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Megan K Petti
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Martin T Zanni
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Justin P Lomont
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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24
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Liu H, Zhong H, Xu Z, Zhang Q, Shah SJA, Liu H, Yao X. The misfolding mechanism of the key fragment R3 of tau protein: a combined molecular dynamics simulation and Markov state model study. Phys Chem Chem Phys 2020; 22:10968-10980. [DOI: 10.1039/c9cp06954b] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
All-atom molecular dynamics (MD) simulation combined with Markov state model (MSM) were used to uncover the structural characteristics and misfolding mechanism of the key R3 fragment of tau protein at the atomic level.
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Affiliation(s)
- Hongli Liu
- School of Pharmacy
- Lanzhou University
- Lanzhou 730000
- China
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy
| | - Haiyang Zhong
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry
- Lanzhou University
- Lanzhou 730000
- China
| | - Zerong Xu
- School of Pharmacy
- Lanzhou University
- Lanzhou 730000
- China
| | | | | | - Huanxiang Liu
- School of Pharmacy
- Lanzhou University
- Lanzhou 730000
- China
| | - Xiaojun Yao
- State Key Laboratory of Applied Organic Chemistry and Department of Chemistry
- Lanzhou University
- Lanzhou 730000
- China
- State Key Laboratory of Quality Research in Chinese Medicine
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25
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Yang X, Williams JK, Yan R, Mouradian MM, Baum J. Increased Dynamics of α-Synuclein Fibrils by β-Synuclein Leads to Reduced Seeding and Cytotoxicity. Sci Rep 2019; 9:17579. [PMID: 31772376 PMCID: PMC6879756 DOI: 10.1038/s41598-019-54063-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 10/29/2019] [Indexed: 12/16/2022] Open
Abstract
Alpha-synuclein (αS) fibrils are toxic to cells and contribute to the pathogenesis and progression of Parkinson's disease and other synucleinopathies. β-Synuclein (βS), which co-localizes with αS, has been shown to provide a neuroprotective effect, but the molecular mechanism by which this occurs remains elusive. Here we show that αS fibrils formed in the presence of βS are less cytotoxic, exhibit reduced cell seeding capacity and are more resistant to fibril shedding compared to αS fibrils alone. Using solid-state NMR, we found that the overall structure of the core of αS fibrils when co-incubated with βS is minimally perturbed, however, the dynamics of Lys and Thr residues, located primarily in the imperfect KTKEGV repeats of the αS N-terminus, are increased. Our results suggest that amyloid fibril dynamics may play a key role in modulating toxicity and seeding. Thus, enhancing the dynamics of amyloid fibrils may be a strategy for future therapeutic targeting of neurodegenerative diseases.
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Affiliation(s)
- Xue Yang
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854, USA
| | - Jonathan K Williams
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854, USA
| | - Run Yan
- RWJMS Institute for Neurological Therapeutics, Rutgers Biomedical and Health Sciences, and Department of Neurology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, 08854, USA
| | - M Maral Mouradian
- RWJMS Institute for Neurological Therapeutics, Rutgers Biomedical and Health Sciences, and Department of Neurology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, 08854, USA
| | - Jean Baum
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854, USA.
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26
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The Role of Protein Misfolding and Tau Oligomers (TauOs) in Alzheimer's Disease (AD). Int J Mol Sci 2019; 20:ijms20194661. [PMID: 31547024 PMCID: PMC6802364 DOI: 10.3390/ijms20194661] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 11/25/2022] Open
Abstract
Although the causative role of the accumulation of amyloid β 1–42 (Aβ42) deposits in the pathogenesis of Alzheimer’s disease (AD) has been under debate for many years, it is supposed that the toxicity soluble oligomers of Tau protein (TauOs) might be also the pathogenic factor acting on the initial stages of this disease. Therefore, we performed a thorough search for literature pertaining to our investigation via the MEDLINE/PubMed database. It was shown that soluble TauOs, especially granular forms, may be the most toxic form of this protein. Hyperphosphorylated TauOs can reduce the number of synapses by missorting into axonal compartments of neurons other than axon. Furthermore, soluble TauOs may be also responsible for seeding Tau pathology within AD brains, with probable link to AβOs toxicity. Additionally, the concentrations of TauOs in the cerebrospinal fluid (CSF) and plasma of AD patients were higher than in non-demented controls, and revealed a negative correlation with mini-mental state examination (MMSE) scores. It was postulated that adding the measurements of TauOs to the panel of CSF biomarkers could improve the diagnosis of AD.
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Jaroniec CP. Two decades of progress in structural and dynamic studies of amyloids by solid-state NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 306:42-47. [PMID: 31311708 PMCID: PMC6703944 DOI: 10.1016/j.jmr.2019.07.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 06/22/2019] [Accepted: 07/08/2019] [Indexed: 05/09/2023]
Abstract
In this perspective article I briefly highlight the rapid progress made over the past two decades in atomic level structural and dynamic studies of amyloids, which are representative of non-crystalline biomacromolecular assemblies, by magic-angle spinning solid-state NMR spectroscopy. Given new and continuing developments in solid-state NMR instrumentation and methodology, ongoing research in this area promises to contribute to an improved understanding of amyloid structure, polymorphism, interactions, assembly mechanisms, and biological function and toxicity.
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Affiliation(s)
- Christopher P Jaroniec
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA.
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In vitro 0N4R tau fibrils contain a monomorphic β-sheet core enclosed by dynamically heterogeneous fuzzy coat segments. Proc Natl Acad Sci U S A 2019; 116:16357-16366. [PMID: 31358628 DOI: 10.1073/pnas.1906839116] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Misfolding of the microtubule-binding protein tau into filamentous aggregates is characteristic of many neurodegenerative diseases such as Alzheimer's disease and progressive supranuclear palsy. Determining the structures and dynamics of these tau fibrils is important for designing inhibitors against tau aggregation. Tau fibrils obtained from patient brains have been found by cryo-electron microscopy to adopt disease-specific molecular conformations. However, in vitro heparin-fibrillized 2N4R tau, which contains all four microtubule-binding repeats (4R), was recently found to adopt polymorphic structures. Here we use solid-state NMR spectroscopy to investigate the global fold and dynamics of heparin-fibrillized 0N4R tau. A single set of 13C and 15N chemical shifts was observed for residues in the four repeats, indicating a single β-sheet conformation for the fibril core. This rigid core spans the R2 and R3 repeats and adopts a hairpin-like fold that has similarities to but also clear differences from any of the polymorphic 2N4R folds. Obtaining a homogeneous fibril sample required careful purification of the protein and removal of any proteolytic fragments. A variety of experiments and polarization transfer from water and mobile side chains indicate that 0N4R tau fibrils exhibit heterogeneous dynamics: Outside the rigid R2-R3 core, the R1 and R4 repeats are semirigid even though they exhibit β-strand character and the proline-rich domains undergo large-amplitude anisotropic motions, whereas the two termini are nearly isotropically flexible. These results have significant implications for the structure and dynamics of 4R tau fibrils in vivo.
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29
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Cieplak AS. Tau Inclusions in Alzheimer's, Chronic Traumatic Encephalopathy and Pick's Disease. A Speculation on How Differences in Backbone Polarization Underlie Divergent Pathways of Tau Aggregation. Front Neurosci 2019; 13:488. [PMID: 31156372 PMCID: PMC6530265 DOI: 10.3389/fnins.2019.00488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/29/2019] [Indexed: 12/13/2022] Open
Abstract
Tau-related dementias appear to involve specific to each disease aggregation pathways and morphologies of filamentous tau assemblies. To understand etiology of these differences, here we elucidate molecular mechanism of formation of tau PHFs based on the PMO theory of misfolding and aggregation of pleiomorphic proteins associated with neurodegenerative diseases. In this model, fibrillization of tau is initiated by the coupled binding and folding of the MTB domains that yields antiparallel homodimers, in analogy to folding of split inteins. The free energy of binding is minimized when the antiparallel alignment brings about backbone-backbone H-bonding between the MTBD segments of similar “strand” propensities. To assess these propensities, a function of the NMR shielding tensors of the Cα atoms is introduced as the folding potential function FPi; the Cα tensors are obtained by the quantum mechanical modeling of protein secondary structure (GIAO//B3LYP/D95**). The calculated FPi plots show that the “strand” propensities of the MBTD segments, and hence the homodimer's register, can be affected by the relatively small changes in the environment's pH, as a result of protonation of MBTD's conserved histidines. The assembly of the antiparallel tau dimers into granular aggregates and their subsequent conversion into the parallel cross-β structure of paired helical filaments is expected to follow the same path as the previously described fibrillization of Aβ. Consequently, the core structure of the nascent tau fibril is determined by the register of the tau homodimer. This model accounts for the reported differences in (i) fibril-core structure of in vivo and in vitro filaments, (ii) cross-seeding of isoforms, (iii) effects of reducing/non-reducing conditions, (iv) effects of PHF6 mutations, and (v) homologs' aggregation properties. The proposed model also suggests that in contrast to Alzheimer's and chronic traumatic encephalopathy disease, the assembly of tau prions in Pick's disease would be facilitated by a moderate drop in pH that accompanies e.g., transit in the endosomal system, inflammation response or an ischemic injury.
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Affiliation(s)
- Andrzej Stanisław Cieplak
- Department of Chemistry, Bilkent University, Ankara, Turkey.,Department of Chemistry, Yale University, New Haven, CT, United States.,Department of Chemistry, Brandeis University, Waltham, MA, United States
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30
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Abstract
Tau is a microtubule-associated protein involved in the regulation of axonal microtubules in neurons. In pathological conditions, it forms fibrils that are molecular hallmarks of neurological disorders known as tauopathies. In the last 2 years, cryo-EM has given unprecedented high-resolution views of Tau in both physiological and pathological conditions. We review here these new findings and put them into the context of the knowledge about Tau before this structural breakthrough. The first structures of Tau fibrils, a molecular hallmark of Alzheimer's disease (AD), were based on fibrils from the brain of an individual with AD and, along with similar patient-derived structures, have set the gold standard for the field. Cryo-EM structures of Tau fibers in three distinct diseases, AD, Pick's disease, and chronic traumatic encephalopathy, represent the end points of Tau's molecular trajectory. We propose that the recent Tau structures may call for a re-examination of databases that link different Tau variants to various forms of dementia. We also address the question of how this structural information may link Tau's functional and pathological aspects. Because this structural information on Tau was obtained in a very short period, the new structures should be viewed in light of earlier structural observations and past and present functional data to shed additional light on Tau function and dysfunction.
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Affiliation(s)
- Guy Lippens
- From the Laboratoire d'Ingénierie des Systèmes Biologiques (LISBP), Université de Toulouse, CNRS, INRA, INSA, 135 avenue de Rangueil, 31077 Toulouse Cedex 04, France and
| | - Benoît Gigant
- the Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France
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31
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Kumar H, Udgaonkar JB. Mechanistic approaches to understand the prion-like propagation of aggregates of the human tau protein. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:922-932. [PMID: 30986567 DOI: 10.1016/j.bbapap.2019.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 12/13/2022]
Abstract
The dynamic nature of the tau protein under physiological conditions is likely to be critical for it to perform its diverse functions inside a cell. Under some conditions, this intrinsically disordered protein assembles into pathogenic aggregates that are self-perpetuating, toxic and infectious in nature. The role of liquid-liquid phase separation in the initiation of the aggregation reaction remains to be delineated. Depending on the nature of the aggregate, its structure, and its localization, neurodegenerative disorders with diverse clinical features are manifested. The prion-like mechanism by which these aggregates propagate and spread across the brain is not well understood. Various factors (PTMs, mutations) have been strongly associated with the pathological aggregates of tau. However, little is known about how these factors modulate the pathological properties linked to aggregation. This review describes the current progress towards understanding the mechanism of propagation of tau aggregates.
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Affiliation(s)
- Harish Kumar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Jayant B Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India; Indian Institute of Science Education and Research, Pune 411008, India.
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32
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Electrostatics of Tau Protein by Molecular Dynamics. Biomolecules 2019; 9:biom9030116. [PMID: 30909607 PMCID: PMC6468555 DOI: 10.3390/biom9030116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 03/19/2019] [Accepted: 03/20/2019] [Indexed: 12/25/2022] Open
Abstract
Tau is a microtubule-associated protein that promotes microtubule assembly and stability. This protein is implicated in several neurodegenerative diseases, including Alzheimer’s. To date, the three-dimensional (3D) structure of tau has not been fully solved, experimentally. Even the most recent information is sometimes controversial in regard to how this protein folds, interacts, and behaves. Predicting the tau structure and its profile sheds light on the knowledge about its properties and biological function, such as the binding to microtubules (MT) and, for instance, the effect on ionic conductivity. Our findings on the tau structure suggest a disordered protein, with discrete portions of well-defined secondary structure, mostly at the microtubule binding region. In addition, the first molecular dynamics simulation of full-length tau along with an MT section was performed, unveiling tau structure when associated with MT and interaction sites. Electrostatics and conductivity were also examined to understand how tau affects the ions in the intracellular fluid environment. Our results bring a new insight into tau and tubulin MT proteins, their characteristics, and the structure–function relationship.
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33
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Selenko P. Quo Vadis Biomolecular NMR Spectroscopy? Int J Mol Sci 2019; 20:ijms20061278. [PMID: 30875725 PMCID: PMC6472163 DOI: 10.3390/ijms20061278] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 02/06/2023] Open
Abstract
In-cell nuclear magnetic resonance (NMR) spectroscopy offers the possibility to study proteins and other biomolecules at atomic resolution directly in cells. As such, it provides compelling means to complement existing tools in cellular structural biology. Given the dominance of electron microscopy (EM)-based methods in current structure determination routines, I share my personal view about the role of biomolecular NMR spectroscopy in the aftermath of the revolution in resolution. Specifically, I focus on spin-off applications that in-cell NMR has helped to develop and how they may provide broader and more generally applicable routes for future NMR investigations. I discuss the use of ‘static’ and time-resolved solution NMR spectroscopy to detect post-translational protein modifications (PTMs) and to investigate structural consequences that occur in their response. I argue that available examples vindicate the need for collective and systematic efforts to determine post-translationally modified protein structures in the future. Furthermore, I explain my reasoning behind a Quinary Structure Assessment (QSA) initiative to interrogate cellular effects on protein dynamics and transient interactions present in physiological environments.
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Affiliation(s)
- Philipp Selenko
- Weizmann Institute of Science, Department of Biological Regulation, 234 Herzl Street, Rehovot 76100, Israel.
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34
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Fichou Y, Al-Hilaly YK, Devred F, Smet-Nocca C, Tsvetkov PO, Verelst J, Winderickx J, Geukens N, Vanmechelen E, Perrotin A, Serpell L, Hanseeuw BJ, Medina M, Buée L, Landrieu I. The elusive tau molecular structures: can we translate the recent breakthroughs into new targets for intervention? Acta Neuropathol Commun 2019; 7:31. [PMID: 30823892 PMCID: PMC6397507 DOI: 10.1186/s40478-019-0682-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 02/20/2019] [Indexed: 12/11/2022] Open
Abstract
Insights into tau molecular structures have advanced significantly in recent years. This field has been the subject of recent breakthroughs, including the first cryo-electron microscopy structures of tau filaments from Alzheimer’s and Pick’s disease inclusions, as well as the structure of the repeat regions of tau bound to microtubules. Tau structure covers various species as the tau protein itself takes many forms. We will here address a range of studies that help to define the many facets of tau protein structures and how they translate into pathogenic forms. New results shed light on previous data that need now to be revisited in order to up-date our knowledge of tau molecular structure. Finally, we explore how these data can contribute the important medical aspects of this research - diagnosis and therapeutics.
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35
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Zhang W, Falcon B, Murzin AG, Fan J, Crowther RA, Goedert M, Scheres SH. Heparin-induced tau filaments are polymorphic and differ from those in Alzheimer's and Pick's diseases. eLife 2019; 8:43584. [PMID: 30720432 PMCID: PMC6375701 DOI: 10.7554/elife.43584] [Citation(s) in RCA: 263] [Impact Index Per Article: 52.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 01/31/2019] [Indexed: 12/17/2022] Open
Abstract
Assembly of microtubule-associated protein tau into filamentous inclusions underlies a range of neurodegenerative diseases. Tau filaments adopt different conformations in Alzheimer’s and Pick’s diseases. Here, we used cryo- and immuno- electron microscopy to characterise filaments that were assembled from recombinant full-length human tau with four (2N4R) or three (2N3R) microtubule-binding repeats in the presence of heparin. 2N4R tau assembles into multiple types of filaments, and the structures of three types reveal similar ‘kinked hairpin’ folds, in which the second and third repeats pack against each other. 2N3R tau filaments are structurally homogeneous, and adopt a dimeric core, where the third repeats of two tau molecules pack in a parallel manner. The heparin-induced tau filaments differ from those of Alzheimer’s or Pick’s disease, which have larger cores with different repeat compositions. Our results illustrate the structural versatility of amyloid filaments, and raise questions about the relevance of in vitro assembly.
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Affiliation(s)
- Wenjuan Zhang
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Benjamin Falcon
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Alexey G Murzin
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Juan Fan
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Michel Goedert
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
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36
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Demers JP, Fricke P, Shi C, Chevelkov V, Lange A. Structure determination of supra-molecular assemblies by solid-state NMR: Practical considerations. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:51-78. [PMID: 30527136 DOI: 10.1016/j.pnmrs.2018.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/15/2018] [Accepted: 06/15/2018] [Indexed: 05/26/2023]
Abstract
In the cellular environment, biomolecules assemble in large complexes which can act as molecular machines. Determining the structure of intact assemblies can reveal conformations and inter-molecular interactions that are only present in the context of the full assembly. Solid-state NMR (ssNMR) spectroscopy is a technique suitable for the study of samples with high molecular weight that allows the atomic structure determination of such large protein assemblies under nearly physiological conditions. This review provides a practical guide for the first steps of studying biological supra-molecular assemblies using ssNMR. The production of isotope-labeled samples is achievable via several means, which include recombinant expression, cell-free protein synthesis, extraction of assemblies directly from cells, or even the study of assemblies in whole cells in situ. Specialized isotope labeling schemes greatly facilitate the assignment of chemical shifts and the collection of structural data. Advanced strategies such as mixed, diluted, or segmental subunit labeling offer the possibility to study inter-molecular interfaces. Detailed and practical considerations are presented with respect to first setting up magic-angle spinning (MAS) ssNMR experiments, including the selection of the ssNMR rotor, different methods to best transfer the sample and prepare the rotor, as well as common and robust procedures for the calibration of the instrument. Diagnostic spectra to evaluate the resolution and sensitivity of the sample are presented. Possible improvements that can reduce sample heterogeneity and improve the quality of ssNMR spectra are reviewed.
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Affiliation(s)
- Jean-Philippe Demers
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany; Laboratory of Cell Biology, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Pascal Fricke
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Chaowei Shi
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Veniamin Chevelkov
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Adam Lange
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany; Institut für Biologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.
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37
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Dan A, Chen HF. Secondary structures transition of tau protein with intrinsically disordered proteins specific force field. Chem Biol Drug Des 2018; 93:242-253. [PMID: 30259679 DOI: 10.1111/cbdd.13407] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/13/2018] [Accepted: 09/15/2018] [Indexed: 02/06/2023]
Abstract
Microtubule-associated Tau protein plays a key role in assembling microtubule and modulating the functional organization of the neuron and developing axonal morphology, growth, and polarity. The pathological Tau can aggregate into cross-beta amyloid as one of the hallmarks for Alzheimer's disease (AD). Therefore, one of the top priorities in AD research is to figure out the structural model of Tau aggregation and to screen the inhibitors. The latest generation intrinsically disordered protein specific force field ff14IDPSFF significantly improved the distributions of heterogeneous conformations for intrinsically disordered proteins (IDPs). Here, the molecular dynamics (MD) simulations with three force fields of ff14SB, ff14IDPs, and ff14IDPSFF were employed to investigate the secondary structures transition of Tau (267-312) fragment. The results indicate that ff14IDPSFF can generate more heterogeneous conformers, and the predicted secondary structural distribution is closer to that of the experimental observation. In addition, predicted secondary chemical shifts from ff14IDPSFF are the most approach to those of experiment. Secondary structures transition kinetics for Tau(267-312) with ff14IDPSFF shows that the secondary structures were gradually transformed from α-helix to β-strand and the β-strand located at the regions of the residues 274-280 and residues 305-311. Besides, the driving force for the secondary structures transition of Tau(267-312) is mainly hydrophobic interactions which located at hexa-peptides 275 VQIINK280 and 306 VQIVYK311 . Secondary structure transition of Tau protein can give insight into the aggregation mechanism for AD.
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Affiliation(s)
- Aohuan Dan
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, SJTU-Yale Joint Center for Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Hai-Feng Chen
- State Key Laboratory of Microbial Metabolism, Department of Bioinformatics and Biostatistics, SJTU-Yale Joint Center for Biostatistics, National Experimental Teaching Center for Life Sciences and Biotechnology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Center for Bioinformation Technology, Shanghai, China
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38
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Kumar H, Udgaonkar JB. Mechanistic and Structural Origins of the Asymmetric Barrier to Prion-like Cross-Seeding between Tau-3R and Tau-4R. J Mol Biol 2018; 430:5304-5312. [PMID: 30267747 DOI: 10.1016/j.jmb.2018.09.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/04/2018] [Accepted: 09/12/2018] [Indexed: 01/19/2023]
Abstract
The spread and deposition of infectious fibrillar protein aggregates in the brain via a prion-like mechanism is a critical component in the patho-physiology of various neurodegenerative diseases, including the tauopathies. In tauopathies, two isoforms of tau, containing three and four microtubule binding repeats, are found to aggregate, and the type of isoform present in aggregates determines the type of tauopathy. Cross-seeding between the two tau isoforms is limited by an asymmetric barrier similar to the species barrier that restricts prion transmission across species, whose origin has remained unclear. In this study, the growth of the tau fibrils is shown to be describable by a two-step Michaelis-Menten-like model. Delineation of the mechanism as a Michaelis-Menten-like mechanism has enabled a quantitative understanding of the asymmetric seeding barrier that exists between two isoforms of tau, tau-K18 and tau-K19 (which differ in containing four and three microtubule binding repeats, respectively), wherein tau-K18 fibrils cannot seed tau-K19 monomer. Furthermore, high-resolution structural analysis of the two isoforms shows that the structural core is more ordered in tau-K19 than in tau-K18. Hence, the current work provides kinetic and structural rationales for asymmetric seeding barriers in general and for the two tau isoforms in particular.
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Affiliation(s)
- Harish Kumar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Jayant B Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India.
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Conformational heterogeneity of tau: Implication on intrinsic disorder, acid stability and fibrillation in Alzheimer's disease. Biophys Chem 2018; 241:27-37. [PMID: 30081240 DOI: 10.1016/j.bpc.2018.07.005] [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: 06/12/2018] [Revised: 07/17/2018] [Accepted: 07/24/2018] [Indexed: 11/20/2022]
Abstract
The self-assembly of intrinsically disordered protein tau into paired helical filament forms one of the hallmarks of Alzheimer's disease. However, the facets of innately disordered structure of tau and its conversion to a β-sheet-rich fibril during several tauopathies are poorly understood. Here, we provide a direct insight into the ensemble of highly heterogeneous conformational families of tau at physiological pH, by nano-electrospray mass spectrometry coupled with ion mobility. The average collision cross section of the most unfolded conformer was higher by >2 fold than that of the most folded one. Acidic pH largely induced unfolding in tau, obliterating the compact conformers completely. The highly unfolded conformers were the key species bestowing the unusual solubility to tau at low pH, with limited contribution from intramolecular long-range interfaces giving rise to ordered conformers. Contrarily, alkaline pH shifted tau towards folded conformations due to charge neutralization, keeping the overall random coil architecture intact. Intriguingly, the heparin-induced in vitro aggregation propensity of the protein attenuated at both acidic and alkaline pH, illustrating the significance of altered conformations in pathological functions of tau. Our observations at low pH indicate that a reorganization of the intricate network of momentary long-range contacts in tau might have implication in its aggregation pathology. Disease-modifying therapies for Alzheimer's disease targeting either to disrupt the essential fibril-forming interaction at third microtubule-binding repeat of tau or to perturb specific binding interaction of tau with endogenous polyanionic species might be of high benefit.
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40
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Amyloid by Design: Intrinsic Regulation of Microbial Amyloid Assembly. J Mol Biol 2018; 430:3631-3641. [PMID: 30017921 DOI: 10.1016/j.jmb.2018.07.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/01/2018] [Accepted: 07/09/2018] [Indexed: 12/14/2022]
Abstract
The term amyloid has historically been used to describe fibrillar aggregates formed as the result of protein misfolding and that are associated with a range of diseases broadly termed amyloidoses. The discovery of "functional amyloids" expanded the amyloid umbrella to encompass aggregates structurally similar to disease-associated amyloids but that engage in a variety of biologically useful tasks without incurring toxicity. The mechanisms by which functional amyloid systems ensure nontoxic assembly has provided insights into potential therapeutic strategies for treating amyloidoses. Some of the most-studied functional amyloids are ones produced by bacteria. Curli amyloids are extracellular fibers made by enteric bacteria that function to encase and protect bacterial communities during biofilm formation. Here we review recent studies highlighting microbial functional amyloid assembly systems that are tailored to enable the assembly of non-toxic amyloid aggregates.
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41
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Smolek T, Jadhav S, Brezovakova V, Cubinkova V, Valachova B, Novak P, Zilka N. First-in-Rat Study of Human Alzheimer's Disease Tau Propagation. Mol Neurobiol 2018; 56:621-631. [PMID: 29770957 DOI: 10.1007/s12035-018-1102-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 05/01/2018] [Indexed: 10/16/2022]
Abstract
One of the key features of misfolded tau in human neurodegenerative disorders is its propagation from one brain area into many others. In the last decade, in vivo tau spreading has been replicated in several mouse transgenic models expressing mutated human tau as well as in normal non-transgenic mice. In this study, we demonstrate for the first time that insoluble tau isolated from human AD brain induces full-blown neurofibrillary pathology in a sporadic rat model of tauopathy expressing non-mutated truncated tau protein. By using specific monoclonal antibodies, we were able to monitor the spreading of tau isolated from human brain directly in the rat hippocampus. We found that exogenous human AD tau was able to spread from the area of injection and induce tau pathology. Interestingly, solubilisation of insoluble AD tau completely abolished the capability of tau protein to induce and spread of neurofibrillary pathology in the rat brain. Our results show that exogenous tau is able to induce and drive neurofibrillary pathology in rat model for human tauopathy in a similar way as it was described in various mouse transgenic models. Rat tau spreading model has many advantages over mouse and other organisms including size and complexity, and thus is highly suitable for identification of pathogenic mechanism of tau spreading.
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Affiliation(s)
- Tomas Smolek
- Institute of Neuroimmunology, Slovak Academy of Sciences, Centre of Excellence for Alzheimer's Disease and Related Disorders, Dubravska 9, 845 10, Bratislava, Slovak Republic.,Axon Neuroscience R&D Services SE, Dvořákovo nábrežie 10, Bratislava, Slovak Republic
| | - Santosh Jadhav
- Institute of Neuroimmunology, Slovak Academy of Sciences, Centre of Excellence for Alzheimer's Disease and Related Disorders, Dubravska 9, 845 10, Bratislava, Slovak Republic.,Axon Neuroscience R&D Services SE, Dvořákovo nábrežie 10, Bratislava, Slovak Republic
| | - Veronika Brezovakova
- Institute of Neuroimmunology, Slovak Academy of Sciences, Centre of Excellence for Alzheimer's Disease and Related Disorders, Dubravska 9, 845 10, Bratislava, Slovak Republic
| | - Veronika Cubinkova
- Institute of Neuroimmunology, Slovak Academy of Sciences, Centre of Excellence for Alzheimer's Disease and Related Disorders, Dubravska 9, 845 10, Bratislava, Slovak Republic.,Axon Neuroscience R&D Services SE, Dvořákovo nábrežie 10, Bratislava, Slovak Republic
| | - Bernadeta Valachova
- Institute of Neuroimmunology, Slovak Academy of Sciences, Centre of Excellence for Alzheimer's Disease and Related Disorders, Dubravska 9, 845 10, Bratislava, Slovak Republic
| | - Petr Novak
- Institute of Neuroimmunology, Slovak Academy of Sciences, Centre of Excellence for Alzheimer's Disease and Related Disorders, Dubravska 9, 845 10, Bratislava, Slovak Republic.,Axon Neuroscience CRM Services SE, Dvořákovo nábrežie 10, Bratislava, Slovak Republic
| | - Norbert Zilka
- Institute of Neuroimmunology, Slovak Academy of Sciences, Centre of Excellence for Alzheimer's Disease and Related Disorders, Dubravska 9, 845 10, Bratislava, Slovak Republic. .,Axon Neuroscience R&D Services SE, Dvořákovo nábrežie 10, Bratislava, Slovak Republic.
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Chukwu JE, Pedersen JT, Pedersen LØ, Volbracht C, Sigurdsson EM, Kong XP. Tau Antibody Structure Reveals a Molecular Switch Defining a Pathological Conformation of the Tau Protein. Sci Rep 2018; 8:6209. [PMID: 29670132 PMCID: PMC5906480 DOI: 10.1038/s41598-018-24276-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/06/2018] [Indexed: 01/24/2023] Open
Abstract
Tau antibodies have shown therapeutic potential for Alzheimer's disease and several are in clinical trials. As a microtubule-associated protein, tau relies on dynamic phosphorylation for its normal functions. In tauopathies, it becomes hyperphosphorylated and aggregates into toxic assemblies, which collectively lead to neurodegeneration. Of the phospho-epitopes, the region around Ser396 has received particular attention because of its prominence and stability in tauopathies. Here we report the first structure of a monoclonal tau antibody in complex with the pathologically important phospho-Ser396 residue. Its binding region reveals tau residues Tyr394 to phospho-Ser396 stabilized in a β-strand conformation that is coordinated by a phospho-specific antigen binding site. These details highlight a molecular switch that defines this prominent conformation of tau and ways to target it. Overall, the structure of the antibody-antigen complex clarifies why certain phosphorylation sites in tau are more closely linked to neurodegeneration than others.
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Affiliation(s)
- Jessica E Chukwu
- Departments of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Jan T Pedersen
- Neurodegeneration, H. Lundbeck A/S, DK-2500, Valby, Denmark
| | | | | | - Einar M Sigurdsson
- Neuroscience & Physiology, & Psychiatry, New York University School of Medicine, New York, NY, USA.
| | - Xiang-Peng Kong
- Departments of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA.
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Jangholi A, Ashrafi-Kooshk MR, Arab SS, Karima S, Poorebrahim M, Ghadami SA, Moosavi-Movahedi AA, Khodarahmi R. Can any “non-specific charge modification within microtubule binding domains of Tau” be a prerequisite of the protein amyloid aggregation? An in vitro study on the 1N4R isoform. Int J Biol Macromol 2018; 109:188-204. [DOI: 10.1016/j.ijbiomac.2017.12.071] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 12/07/2017] [Accepted: 12/11/2017] [Indexed: 01/26/2023]
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Abstract
A pathway from the natively unfolded microtubule-associated protein Tau to a highly structured amyloid fibril underlies human Tauopathies. This ordered assembly causes disease and represents the gain of toxic function. In recent years, evidence has accumulated to suggest that Tau inclusions form first in a small number of brain cells, from where they propagate to other regions, resulting in neurodegeneration and disease. Propagation of pathology is often called prion-like, which refers to the capacity of an assembled protein to induce the same abnormal conformation in a protein of the same kind, initiating a self-amplifying cascade. In addition, prion-like encompasses the release of protein aggregates from brain cells and their uptake by neighboring cells. In mice, the intracerebral injection of Tau inclusions induces the ordered assembly of monomeric Tau, followed by its spreading to distant brain regions. Conformational differences between Tau aggregates from transgenic mouse brain and in vitro assembled recombinant protein account for the greater seeding potency of brain aggregates. Short fibrils constitute the major species of seed-competent Tau in the brains of transgenic mice. The existence of multiple human Tauopathies with distinct fibril morphologies has led to the suggestion that different molecular conformers (or strains) of aggregated Tau exist.
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Affiliation(s)
- Michel Goedert
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom;
| | - David S Eisenberg
- Department of Biological Chemistry and Howard Hughes Medical Institute, University of California, Los Angeles, California 90095
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45
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Multivalent cross-linking of actin filaments and microtubules through the microtubule-associated protein Tau. Nat Commun 2017; 8:1981. [PMID: 29215007 PMCID: PMC5719408 DOI: 10.1038/s41467-017-02230-8] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 11/15/2017] [Indexed: 11/17/2022] Open
Abstract
Microtubule-associated proteins regulate microtubule dynamics, bundle actin filaments, and cross-link actin filaments with microtubules. In addition, aberrant interaction of the microtubule-associated protein Tau with filamentous actin is connected to synaptic impairment in Alzheimer’s disease. Here we provide insight into the nature of interaction between Tau and actin filaments. We show that Tau uses several short helical segments to bind in a dynamic, multivalent process to the hydrophobic pocket between subdomains 1 and 3 of actin. Although a single Tau helix is sufficient to bind to filamentous actin, at least two, flexibly linked helices are required for actin bundling. In agreement with a structural model of Tau repeat sequences in complex with actin filaments, phosphorylation at serine 262 attenuates binding of Tau to filamentous actin. Taken together the data demonstrate that bundling of filamentous actin and cross-linking of the cellular cytoskeleton depend on the metamorphic and multivalent nature of microtubule-associated proteins. The microtubule associated protein Tau also interacts with filamentous actin. Here the authors combine biophysical experiments and NMR studies to characterize the structural changes that occur in Tau upon binding to filamentous actin and show that phosphorylation of serine 262 attenuates actin binding of Tau.
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Discovery and characterization of stable and toxic Tau/phospholipid oligomeric complexes. Nat Commun 2017; 8:1678. [PMID: 29162800 PMCID: PMC5698329 DOI: 10.1038/s41467-017-01575-4] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 09/29/2017] [Indexed: 11/13/2022] Open
Abstract
The microtubule-associated protein Tau plays a central role in the pathogenesis of Alzheimer’s disease. Although Tau interaction with membranes is thought to affect some of its physiological functions and its aggregation properties, the sequence determinants and the structural and functional consequences of such interactions remain poorly understood. Here, we report that the interaction of Tau with vesicles results in the formation of highly stable protein/phospholipid complexes. These complexes are toxic to primary hippocampal cultures and are detected by MC-1, an antibody recognizing pathological Tau conformations. The core of these complexes is comprised of the PHF6* and PHF6 hexapeptide motifs, the latter in a β-strand conformation. Studies using Tau-derived peptides enabled the design of mutants that disrupt Tau interactions with phospholipids without interfering with its ability to form fibrils, thus providing powerful tools for uncoupling these processes and investigating the role of membrane interactions in regulating Tau function, aggregation and toxicity. The Alzheimer protein Tau interacts with biological membranes, but the role of these interactions in regulating Tau function in health and disease remains unexplored. Here, the authors report on the discovery and characterization of neurotoxic oligomeric protein/phospholipid complexes.
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Jiji AC, Arshad A, Dhanya SR, Shabana PS, Mehjubin CK, Vijayan V. Zn2+
Interrupts R4-R3 Association Leading to Accelerated Aggregation of Tau Protein. Chemistry 2017; 23:16976-16979. [DOI: 10.1002/chem.201704555] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Indexed: 01/06/2023]
Affiliation(s)
- A. C. Jiji
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM); Maruthamala P.O; Thiruvananthapuram-695551 Kerala India
| | - A. Arshad
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM); Maruthamala P.O; Thiruvananthapuram-695551 Kerala India
| | - S. R. Dhanya
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM); Maruthamala P.O; Thiruvananthapuram-695551 Kerala India
| | - P. S. Shabana
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM); Maruthamala P.O; Thiruvananthapuram-695551 Kerala India
| | - C. K. Mehjubin
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM); Maruthamala P.O; Thiruvananthapuram-695551 Kerala India
| | - Vinesh Vijayan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM); Maruthamala P.O; Thiruvananthapuram-695551 Kerala India
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Cieplak AS. Protein folding, misfolding and aggregation: The importance of two-electron stabilizing interactions. PLoS One 2017; 12:e0180905. [PMID: 28922400 PMCID: PMC5603215 DOI: 10.1371/journal.pone.0180905] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 06/22/2017] [Indexed: 12/17/2022] Open
Abstract
Proteins associated with neurodegenerative diseases are highly pleiomorphic and may adopt an all-α-helical fold in one environment, assemble into all-β-sheet or collapse into a coil in another, and rapidly polymerize in yet another one via divergent aggregation pathways that yield broad diversity of aggregates’ morphology. A thorough understanding of this behaviour may be necessary to develop a treatment for Alzheimer’s and related disorders. Unfortunately, our present comprehension of folding and misfolding is limited for want of a physicochemical theory of protein secondary and tertiary structure. Here we demonstrate that electronic configuration and hyperconjugation of the peptide amide bonds ought to be taken into account to advance such a theory. To capture the effect of polarization of peptide linkages on conformational and H-bonding propensity of the polypeptide backbone, we introduce a function of shielding tensors of the Cα atoms. Carrying no information about side chain-side chain interactions, this function nonetheless identifies basic features of the secondary and tertiary structure, establishes sequence correlates of the metamorphic and pH-driven equilibria, relates binding affinities and folding rate constants to secondary structure preferences, and manifests common patterns of backbone density distribution in amyloidogenic regions of Alzheimer’s amyloid β and tau, Parkinson’s α-synuclein and prions. Based on those findings, a split-intein like mechanism of molecular recognition is proposed to underlie dimerization of Aβ, tau, αS and PrPC, and divergent pathways for subsequent association of dimers are outlined; a related mechanism is proposed to underlie formation of PrPSc fibrils. The model does account for: (i) structural features of paranuclei, off-pathway oligomers, non-fibrillar aggregates and fibrils; (ii) effects of incubation conditions, point mutations, isoform lengths, small-molecule assembly modulators and chirality of solid-liquid interface on the rate and morphology of aggregation; (iii) fibril-surface catalysis of secondary nucleation; and (iv) self-propagation of infectious strains of mammalian prions.
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Affiliation(s)
- Andrzej Stanisław Cieplak
- Department of Chemistry, Bilkent University, Ankara, Turkey
- Department of Chemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, United States of America
- * E-mail:
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Wang T, Jo H, DeGrado WF, Hong M. Water Distribution, Dynamics, and Interactions with Alzheimer's β-Amyloid Fibrils Investigated by Solid-State NMR. J Am Chem Soc 2017; 139:6242-6252. [PMID: 28406028 PMCID: PMC5808936 DOI: 10.1021/jacs.7b02089] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Water is essential for protein folding and assembly of amyloid fibrils. Internal water cavities have been proposed for several amyloid fibrils, but no direct structural and dynamical data have been reported on the water dynamics and site-specific interactions of water with the fibrils. Here we use solid-state NMR spectroscopy to investigate the water interactions of several Aβ40 fibrils. 1H spectral lineshapes, T2 relaxation times, and two-dimensional (2D) 1H-13C correlation spectra show that there are five distinct water pools: three are peptide-bound water, while two are highly dynamic water that can be assigned to interfibrillar water and bulk-like matrix water. All these water pools are associated with the fibrils on the nanometer scale. Water-transferred 2D correlation spectra allow us to map out residue-specific hydration and give evidence for the presence of a water pore in the center of the three-fold symmetric wild-type Aβ40 fibril. In comparison, the loop residues and the intramolecular strand-strand interface have low hydration, excluding the presence of significant water cavities in these regions. The Osaka Aβ40 mutant shows lower hydration and more immobilized water than wild-type Aβ40, indicating the influence of peptide structure on the dynamics and distribution of hydration water. Finally, the highly mobile interfibrillar and matrix water exchange with each other on the time scale of seconds, suggesting that fibril bundling separates these two water pools, and water molecules must diffuse along the fibril axis before exchanging between these two environments. These results provide insights and experimental constraints on the spatial distribution and dynamics of water pools in these amyloid fibrils.
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Affiliation(s)
- Tuo Wang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Hyunil Jo
- Department of Pharmaceutical Chemistry and Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California 94143, United States
| | - William F. DeGrado
- Department of Pharmaceutical Chemistry and Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, California 94143, United States
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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50
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Grohe K, Movellan KT, Vasa SK, Giller K, Becker S, Linser R. Non-equilibrium hydrogen exchange for determination of H-bond strength and water accessibility in solid proteins. JOURNAL OF BIOMOLECULAR NMR 2017; 68:7-17. [PMID: 28393279 DOI: 10.1007/s10858-017-0110-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 04/02/2017] [Indexed: 06/07/2023]
Abstract
We demonstrate measurement of non-equilibrium backbone amide hydrogen-deuterium exchange rates (HDX) for solid proteins. The target of this study are the slowly exchanging residues in solid samples, which are associated with stable secondary-structural elements of proteins. These hydrogen exchange processes escape methods measuring equilibrium exchange rates of faster processes. The method was applied to a micro-crystalline preparation of the SH3 domain of chicken α-spectrin. Therefore, from a 100% back-exchanged micro-crystalline protein preparation, the supernatant buffer was exchanged by a partially deuterated buffer to reach a final protonation level of approximately 20% before packing the sample in a 1.3 mm rotor. Tracking of the HN peak intensities for 2 weeks reports on site-specific hydrogen bond strength and also likely reflects water accessibility in a qualitative manner. H/D exchange can be directly determined for hydrogen-bonded amides using 1H detection under fast magic angle spinning. This approach complements existing methods and provides the means to elucidate interesting site-specific characteristics for protein functionality in the solid state.
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Affiliation(s)
- Kristof Grohe
- Department Chemie und Pharmazie, Ludwig-Maximilians-Universität München, 81377, Munich, Germany
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Kumar Tekwani Movellan
- Department Chemie und Pharmazie, Ludwig-Maximilians-Universität München, 81377, Munich, Germany
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Suresh Kumar Vasa
- Department Chemie und Pharmazie, Ludwig-Maximilians-Universität München, 81377, Munich, Germany
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Karin Giller
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Stefan Becker
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Rasmus Linser
- Department Chemie und Pharmazie, Ludwig-Maximilians-Universität München, 81377, Munich, Germany.
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.
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