1
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Naeimi WR, Serio TR. Beyond Amyloid Fibers: Accumulation, Biological Relevance, and Regulation of Higher-Order Prion Architectures. Viruses 2022; 14:v14081635. [PMID: 35893700 PMCID: PMC9332770 DOI: 10.3390/v14081635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/14/2022] [Accepted: 07/23/2022] [Indexed: 12/19/2022] Open
Abstract
The formation of amyloid fibers is associated with a diverse range of disease and phenotypic states. These amyloid fibers often assemble into multi-protofibril, high-order architectures in vivo and in vitro. Prion propagation in yeast, an amyloid-based process, represents an attractive model to explore the link between these aggregation states and the biological consequences of amyloid dynamics. Here, we integrate the current state of knowledge, highlight opportunities for further insight, and draw parallels to more complex systems in vitro. Evidence suggests that high-order fibril architectures are present ex vivo from disease relevant environments and under permissive conditions in vivo in yeast, including but not limited to those leading to prion formation or instability. The biological significance of these latter amyloid architectures or how they may be regulated is, however, complicated by inconsistent experimental conditions and analytical methods, although the Hsp70 chaperone Ssa1/2 is likely involved. Transition between assembly states could form a mechanistic basis to explain some confounding observations surrounding prion regulation but is limited by a lack of unified methodology to biophysically compare these assembly states. Future exciting experimental entryways may offer opportunities for further insight.
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2
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Sharma A, Anand JS, Kumar Y. Immunotherapeutics for AD: A Work in Progress. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2021; 21:752-765. [PMID: 34477533 DOI: 10.2174/1871527320666210903101522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 04/30/2021] [Accepted: 06/25/2021] [Indexed: 11/22/2022]
Abstract
Alzheimer's Disease (AD), often called the 'Plague of the 21st Century,' is a progressive, irreversible neurodegenerative disorder that leads to the degeneration and death of neurons. Multiple factors, such as genetic defects, epigenetic regulations, environmental factors, or cerebrovascular damage, are a manifestation of the neurodegenerative process that begins to occur decades before the onset of disease. To date, no treatment or therapeutic strategy has proven to be potent in inhibiting its progress or reversing the effects of the disease. The ever-increasing numbers and lack of sufficient therapies that can control or reverse the effects of the disease have propelled research in the direction of devising efficient therapeutic strategies for AD. This review comprehensively discusses the active and passive immunotherapies against Amyloid-β and Tau protein, which remain the popular choice of targets for AD therapeutics. Some of the prospective immunotherapies against Aβ plaques have failed due to various reasons. Much of the research is focused on targeting Tau, specifically, targeting the mid-region of extracellular Tau due to their potential to prevent seeding and hence the spread of neurofibrillary tangles (NFTs). Thus, there is a need to thoroughly understand the disease onset mechanisms and discover effective therapeutic strategies.
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Affiliation(s)
- Anuja Sharma
- Department of Biological Sciences and Engineering (BSE), Netaji Subhas University of Technology, New Delhi, 110078, India
| | - Jaspreet Singh Anand
- University College of Medical Sciences (UCMS), University of Delhi, New Delhi, 110095, India
| | - Yatender Kumar
- Department of Biological Sciences and Engineering (BSE), Netaji Subhas University of Technology, New Delhi, 110078, India
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3
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Heo C, Ha T, You C, Huynh T, Lim H, Kim J, Kesama MR, Lee J, Kim TT, Lee YH. Identifying Fibrillization State of Aβ Protein via Near-Field THz Conductance Measurement. ACS NANO 2020; 14:6548-6558. [PMID: 32167289 DOI: 10.1021/acsnano.9b08572] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Progressive Alzheimer's disease is correlated with the oligomerization and fibrillization of the amyloid beta (Aβ) protein. We identify the fibrillization stage of the Aβ protein through label-free near-field THz conductance measurements in a buffer solution. Frequency-dependent conductance was obtained by measuring the differential transmittance of the time-domain spectroscopy in the THz range with a molar concentration of monomer, oligomer, and fibrillar forms of the Aβ protein. Conductance at the lower frequency limit was observed to be high in monomers, reduced in oligomers, and dropped to an insulating state in fibrils and increased proportionally with the Aβ protein concentration. The monotonic decrease in the conductance at low frequency was dominated by a simple Drude component in the monomer with concentration and nonlinear conductance behaviors in the oligomer and fibril. By extracting the structural localization parameter, a dimensionless constant, with the modified Drude-Smith model, we defined a dementia quotient (DQ) value (0 < De < 1) as a discrete metric for a various Aβ proteins at a low concentration of 0.1 μmol/L; DQ = 1.0 ± 0.002 (fibril by full localization, mainly by Smith component), DQ = 0.64 ± 0.013 (oligomer by intermixed localization), and DQ = 0.0 ± 0.000 (monomer by Drude component). DQ values were discretely preserved independent of the molar concentration or buffer variation. This provides plenty of room for the label-free diagnosis of Alzheimer's disease using the near-field THz conductance measurement.
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Affiliation(s)
- Chaejeong Heo
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Institute for Quantum Biophysics (IQB), Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Taewoo Ha
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
| | - Chunjae You
- Institute for Quantum Biophysics (IQB), Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Biophysics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Thuy Huynh
- Institute for Quantum Biophysics (IQB), Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Biophysics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hosub Lim
- Department of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jiwon Kim
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Mallikarjuna Reddy Kesama
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Institute for Quantum Biophysics (IQB), Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jinkee Lee
- Institute for Quantum Biophysics (IQB), Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Mechanical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Teun-Teun Kim
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Suwon 16419, Republic of Korea
- Department of Energy Science and Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
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4
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Falcone E, Ahmed IMM, Oliveri V, Bellia F, Vileno B, El Khoury Y, Hellwig P, Faller P, Vecchio G. Acrolein and Copper as Competitive Effectors of α‐Synuclein. Chemistry 2020; 26:1871-1879. [DOI: 10.1002/chem.201904885] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Indexed: 11/06/2022]
Affiliation(s)
- Enrico Falcone
- Dipartimento di Scienze ChimicheUniversità degli Studi di Catania A. Doria 6 95125 Catania Italy
- Institut de Chimie, UMR 7177CNRSUniversité de Strasbourg 4 Rue Blaise Pascal 67000 Strasbourg France
| | - Ikhlas M. M. Ahmed
- Istituto di CristallografiaConsiglio Nazionale delle Ricerche P. Gaifami 18 95126 Catania Italy
- Dipartimento di Scienze ChimicheUniversità degli Studi di Catania A. Doria 6 95125 Catania Italy
| | - Valentina Oliveri
- Dipartimento di Scienze ChimicheUniversità degli Studi di Catania A. Doria 6 95125 Catania Italy
| | - Francesco Bellia
- Istituto di CristallografiaConsiglio Nazionale delle Ricerche P. Gaifami 18 95126 Catania Italy
| | - Bertrand Vileno
- Institut de Chimie, UMR 7177CNRSUniversité de Strasbourg 4 Rue Blaise Pascal 67000 Strasbourg France
- French EPR Federation of ResearchFédération IR-RPE CNRS 67081 Strasbourg France
| | - Youssef El Khoury
- Laboratoire de bioélectrochimie et spectroscopie, UMR 7140CNRSUniversité de Strasbourg 4 Rue Blaise Pascal 67081 Strasbourg France
| | - Petra Hellwig
- Laboratoire de bioélectrochimie et spectroscopie, UMR 7140CNRSUniversité de Strasbourg 4 Rue Blaise Pascal 67081 Strasbourg France
- Institute for Advanced Study (USIAS)Université de Strasbourg 5 allée du Général Rouvillois 67083 Strasbourg France
| | - Peter Faller
- Institut de Chimie, UMR 7177CNRSUniversité de Strasbourg 4 Rue Blaise Pascal 67000 Strasbourg France
| | - Graziella Vecchio
- Dipartimento di Scienze ChimicheUniversità degli Studi di Catania A. Doria 6 95125 Catania Italy
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5
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Timchenko M, Abdullatypov A, Kihara H, Timchenko A. Effect of Single Amino Acid Substitutions by Asn and Gln on Aggregation Properties of Bence-Jones Protein BIF. Int J Mol Sci 2019; 20:ijms20205197. [PMID: 31635169 PMCID: PMC6834151 DOI: 10.3390/ijms20205197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 10/17/2019] [Accepted: 10/19/2019] [Indexed: 11/24/2022] Open
Abstract
The nature of renal amyloidosis involving Bence-Jones proteins in multiple myeloma is still unclear. The development of amyloidosis in neurodegenerative diseases is often associated with a high content of asparagine and glutamine residues in proteins forming amyloid deposits. To estimate the influence of Asn and Gln residues on the aggregation of Bence-Jones protein BIF, we obtained recombinant BIF and its mutants with the substitution of Tyr187→Asn (Y187N) in α-helix of CL domain, Lys170→Asn (K170N) and Ser157→Gln (S157Q) in CL domain loops, Arg109→Asn in VL-CL linker (R109N) and Asp29→Gln in VL domain loop (D29Q). The morphology of protein aggregates was studied at pH corresponding to the conditions in bloodstream (pH 7.2), distal (pH 6.5) and proximal renal tubules (pH 4.5) by atomic force microscopy (AFM) and small-angle X-ray scattering (SAXS). The Lys170→Asn replacement almost completely inhibits amyloidogenic activity. The Y187N forms fibril-like aggregates at all pH values. The Arg109→Asn replacement resulted in formation of fibril-like structures at pH 7.2 and 6.5 while the substitutions by Gln provoked formation of those structures only at pH 7.2. Therefore, the amyloidogenic properties are highly dependent on the location of Asn or Gln.
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Affiliation(s)
- Maria Timchenko
- Laboratory of NMR of Biosystems, Institute of Theoretical and Experimental Biophysics RAS, Pushchino 142290, Russia.
| | - Azat Abdullatypov
- Laboratory of Biotechnology and Physiology of Phototrophic Organisms, Institute of Basic Biological Problems RAS-a separate subdivision of PSCBR RAS (IBBP RAS), Pushchino 142290, Russia.
| | - Hiroshi Kihara
- Himeji-Hinomoto College, 890 Koro, Kodera-cho, Himeji 679-2151, Russia.
| | - Alexander Timchenko
- Laboratory of Protein Physics, Institute of Protein Research RAS, Pushchino 142290, Russia.
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Islam T, Gharibyan AL, Golchin SA, Pettersson N, Brännström K, Hedberg I, Virta MM, Olofsson L, Olofsson A. Apolipoprotein E impairs amyloid-β fibril elongation and maturation. FEBS J 2019; 287:1208-1219. [PMID: 31571352 DOI: 10.1111/febs.15075] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/18/2019] [Accepted: 09/27/2019] [Indexed: 01/01/2023]
Abstract
Alzheimer's disease (AD) is strongly linked to amyloid depositions of the Aβ peptide (Aβ). The lipid-binding protein apolipoprotein E (ApoE) has been found to interfere with Aβ amyloid formation and to exert a strong clinical impact to the pathology of AD. The APOE gene exists in three allelic isoforms represented by APOE ε2, APOE ε3, and APOE ε4. Carriers of the APOE ε4 variant display a gene dose-dependent increased risk of developing the disease. Aβ amyloids are formed via a nucleation-dependent mechanism where free monomers are added onto a nucleus in a template-dependent manner. Using a combination of surface plasmon resonance and thioflavin-T assays, we here show that ApoE can target the process of fibril elongation and that its interference effectively prevents amyloid maturation. We expose a complex equilibrium where the concentration of ApoE, Aβ monomers, and the amount of already formed Aβ fibrils will affect the relative proportion and formation rate of mature amyloids versus alternative assemblies. The result illustrates a mechanism which may affect both the clearance rate of Aβ assemblies in vivo and the population of cytotoxic Aβ assemblies.
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Affiliation(s)
- Tohidul Islam
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | - Anna L Gharibyan
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | - Solmaz A Golchin
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | - Nina Pettersson
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | | | - Isabell Hedberg
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | - Merit-Miriam Virta
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | - Linnea Olofsson
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | - Anders Olofsson
- Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
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7
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Oliveri V. Toward the discovery and development of effective modulators of α-synuclein amyloid aggregation. Eur J Med Chem 2019; 167:10-36. [PMID: 30743095 DOI: 10.1016/j.ejmech.2019.01.045] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 01/21/2019] [Accepted: 01/21/2019] [Indexed: 12/17/2022]
Abstract
A host of human diseases, including Parkinson's disease and Dementia with Lewy bodies, are suspected to be directly linked to protein aggregation. Amyloid protein aggregates and oligomeric intermediates of α-synuclein are observed in synucleinopathies and considered to be mediators of cellular toxicity. Hence, α-synuclein has seen as one of the leading and most compelling targets and is receiving a great deal of attention from researchers. Nevertheless, there is no neuroprotective approach directed toward Parkinson's disease or other synucleinopathies so far. In this review, we summarize the available data concerning inhibitors of α-synuclein aggregation and their advancing towards clinical use. The compounds are grouped according to their chemical structures, providing respective insights into their mechanism of action, pharmacology, and pharmacokinetics. Overall, shared structure-activity elements are emerging, as well as specific binding modes related to the ability of the modulators to establish hydrophobic and hydrogen bonds interactions with the protein. Some molecules with encouraging in vivo data support the possibility of translation to the clinic.
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Affiliation(s)
- Valentina Oliveri
- Dipartimento di Scienze Chimiche, Università degli Studi di Catania, viale A. Doria 6, 95125, Catania, Italy.
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8
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Strømland Ø, Handegård ØS, Govasli ML, Wen H, Halskau Ø. Peptides derived from α-lactalbumin membrane binding helices oligomerize in presence of lipids and disrupt bilayers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1029-1039. [PMID: 28069414 DOI: 10.1016/j.bbamem.2017.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 12/02/2016] [Accepted: 01/04/2017] [Indexed: 11/16/2022]
Abstract
Helix A and -C of α-lactalbumin, a loosely folded amphitropic protein, perturb lipid monolayers by the formation of amyloid pore-like structures. To investigate whether these helices are able to disrupt fully formed bilayers, we designed peptides comprised of Helix A and -C, and investigated their membrane-perturbing properties. The peptides, designated A-Cage-C and A-Lnk-C, were prepared with tryptophan sites in the helical and the spacer segments in order to monitor which part were involved in membrane association under given conditions. The peptides associate with and disrupt negatively charged bilayers in a pH-dependent manner and α-helical tendencies increased upon membrane association. Both helices and the spacer segment were involved in membrane binding in the case of A-Lnk-C, and there are indications that the two helixes act in synergy to affect the membrane. However, the helices and the spacer segment could not intercalate when present as A-Cage-C at neutral conditions. At acidic pH, both helices could intercalate, but not the central spacer segment. AFM performed on bilayers under aqueous conditions revealed oligomers formed by the peptides. The presence of bilayers and acidic pHs were both drivers for the formation of these, suggestive of models for peptide oligomerization where segments of the peptide are stacked in an electrostatically favorable manner by the surface. Of the two peptides, A-Lnk-C was the more prolific oligomerizer, and also formed amyloid-fibril like structures at acidic pH and elevated concentrations. Our results suggest the peptides perturb membranes not through pore-like structures, but possibly by a thinning mechanism.
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Affiliation(s)
- Øyvind Strømland
- Department of Molecular Biology, University of Bergen, Thormøhlensgt. 55, 5008 Bergen, Norway
| | - Ørjan S Handegård
- Department of Molecular Biology, University of Bergen, Thormøhlensgt. 55, 5008 Bergen, Norway
| | - Morten L Govasli
- Department of Molecular Biology, University of Bergen, Thormøhlensgt. 55, 5008 Bergen, Norway
| | - Hanzhen Wen
- Department of Molecular Biology, University of Bergen, Thormøhlensgt. 55, 5008 Bergen, Norway
| | - Øyvind Halskau
- Department of Molecular Biology, University of Bergen, Thormøhlensgt. 55, 5008 Bergen, Norway.
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9
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Kisilevsky R, Raimondi S, Bellotti V. Historical and Current Concepts of Fibrillogenesis and In vivo Amyloidogenesis: Implications of Amyloid Tissue Targeting. Front Mol Biosci 2016; 3:17. [PMID: 27243018 PMCID: PMC4860540 DOI: 10.3389/fmolb.2016.00017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 04/21/2016] [Indexed: 12/22/2022] Open
Abstract
Historical and current concepts of in vitro fibrillogenesis are considered in the light of disorders in which amyloid is deposited at anatomic sites remote from the site of synthesis of the corresponding precursor protein. These clinical conditions set constraints on the interpretation of information derived from in vitro fibrillogenesis studies. They suggest that in addition to kinetic and thermodynamic factors identified in vitro, fibrillogenesis in vivo is determined by site specific factors most of which have yet to be identified.
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Affiliation(s)
- Robert Kisilevsky
- Department of Pathology and Molecular Medicine, Queen's University Kingston, ON, Canada
| | - Sara Raimondi
- Unit of Biochemistry, Department of Molecular Medicine, University of Pavia Pavia, Italy
| | - Vittorio Bellotti
- Unit of Biochemistry, Department of Molecular Medicine, University of PaviaPavia, Italy; Wolfson Drug Discovery Unit, Division of Medicine, Centre for Amyloidosis and Acute Phase Proteins, University College LondonLondon, UK
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10
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Roche J, Shen Y, Lee JH, Ying J, Bax A. Monomeric Aβ(1-40) and Aβ(1-42) Peptides in Solution Adopt Very Similar Ramachandran Map Distributions That Closely Resemble Random Coil. Biochemistry 2016; 55:762-75. [PMID: 26780756 PMCID: PMC4750080 DOI: 10.1021/acs.biochem.5b01259] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
The
pathogenesis of Alzheimer’s disease is characterized
by the aggregation and fibrillation of amyloid peptides Aβ1–40 and Aβ1–42 into amyloid
plaques. Despite strong potential therapeutic interest, the structural
pathways associated with the conversion of monomeric Aβ peptides
into oligomeric species remain largely unknown. In particular, the
higher aggregation propensity and associated toxicity of Aβ1–42 compared to that of Aβ1–40 are poorly understood. To explore in detail the structural propensity
of the monomeric Aβ1–40 and Aβ1–42 peptides in solution, we recorded a large set of nuclear magnetic
resonance (NMR) parameters, including chemical shifts, nuclear Overhauser
effects (NOEs), and J couplings. Systematic comparisons
show that at neutral pH the Aβ1–40 and Aβ1–42 peptides populate almost indistinguishable coil-like
conformations. Nuclear Overhauser effect spectra collected at very
high resolution remove assignment ambiguities and show no long-range
NOE contacts. Six sets of backbone J couplings (3JHNHα, 3JC′C′, 3JC′Hα, 1JHαCα, 2JNCα, and 1JNCα) recorded
for Aβ1–40 were used as input for the recently
developed MERA Ramachandran map analysis, yielding residue-specific
backbone ϕ/ψ torsion angle distributions that closely
resemble random coil distributions, the absence of a significantly
elevated propensity for β-conformations in the C-terminal region
of the peptide, and a small but distinct propensity for αL at K28. Our results suggest that the self-association of
Aβ peptides into toxic oligomers is not driven by elevated propensities
of the monomeric species to adopt β-strand-like conformations.
Instead, the accelerated disappearance of Aβ NMR signals in
D2O over H2O, particularly pronounced for Aβ1–42, suggests that intermolecular interactions between
the hydrophobic regions of the peptide dominate the aggregation process.
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Affiliation(s)
- Julien Roche
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0510, United States
| | - Yang Shen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0510, United States
| | - Jung Ho Lee
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0510, United States
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0510, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0510, United States
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11
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Lo CJ, Wang CC, Huang HB, Chang CF, Shiao MS, Chen YC, Lin TH. The Arctic mutation accelerates Aβ aggregation in SDS through reducing the helical propensity of residues 15-25. Amyloid 2015; 22:8-18. [PMID: 25376379 DOI: 10.3109/13506129.2014.980943] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mutations within the β-amyloid peptide (Aβ) sequence that cause early onset familial Alzheimer's disease (FAD) have been shown to promote Aβ aggregation. How these FAD-related mutants increase the aggregative ability of Aβ is not fully understood. Here, we characterized the effect of the Arctic variant (E22G) on the conformational stability of Aβ using various forms of spectroscopy and kinetic analyses, including nuclear magnetic resonance (NMR), circular dichroism (CD) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM). The E22G mutation in the Arctic variant reduced the α-helical propensity and conformational stability of Aβ on residues 15-25. This mutation also caused an increase in both α-helix-to-β-strand conversion and fibril nucleation rates. Our results suggest that the α-helical propensity of residues 15-25 may play a determinant role in the aggregative ability of Aβ. This may provide a structural basis for understanding the molecular mechanism of Aβ aggregation.
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Affiliation(s)
- Chi-Jen Lo
- Institute of Biochemistry & Molecular Biology, National Yang-Ming University , Taipei, Taiwan , ROC
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12
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A content and structural assessment of oxidative motifs across a diverse set of life forms. Comput Biol Med 2014; 53:179-89. [PMID: 25151511 DOI: 10.1016/j.compbiomed.2014.07.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/14/2014] [Accepted: 07/16/2014] [Indexed: 11/24/2022]
Abstract
Exposure to weightlessness (microgravity) or other protein stresses are detrimental to animal and human protein tissue health. Protein damage has been associated with stress and is linked to aging and the onset of diseases such as Alzheimer׳s, Parkinson׳s, sepsis, and others. Protein stresses may cause alterations to physical protein structure, altering its functional identity. Alterations from stresses such as microgravity may be responsible for forms of muscle atrophy (as noted in returning astronauts), however, protein stresses come from other sources as well. Oxidative carbonylation is a protein stress which is a driving force behind protein decay and is attracted to protein segments enriched in R, K, P, T, E and S residues. Since mitochondria apply oxidative processes to produce ATP, their proteins may be placed in the same danger as those that are exposed to stresses. However, they do not appear to be impacted in the same way. Across 14 diverse organisms, we evaluate the coverage of motifs which are high in the amino acids thought to be affected by protein stresses such as oxidation. For this study, we study RKPT and PEST motifs which are both responsible for attracting forms of oxidation across mitochondrial and non-mitochondrial proteins. We show that mitochondrial proteins have fewer of these oxidative sites compared to non-mitochondrial proteins. Additionally, we analyze the oxidative regions to determine that their motifs preferentially tend to make up the connection points between the four kinds of structures of folded proteins (helices, turns, sheets, and coils).
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13
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Shin B, Oh H, Park SM, Han HE, Ye M, Song WK, Park WJ. Intracellular cleavage of amyloid β by a viral protease NIa prevents amyloid β-mediated cytotoxicity. PLoS One 2014; 9:e98650. [PMID: 24915567 PMCID: PMC4051590 DOI: 10.1371/journal.pone.0098650] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 05/06/2014] [Indexed: 11/19/2022] Open
Abstract
Nuclear inclusion a (NIa) of turnip mosaic virus is a cytosolic protease that cleaves amyloid β (Aβ) when heterologously overexpressed. Lentivirus-mediated expression of NIa in the brains of APP(sw)/PS1 mice significantly reduces cerebral Aβ levels and plaque depositions, and improves behavioral deficits. Here, the effects of NIa and neprilysin (NEP), a well-known Aβ-cleaving protease, on oligomeric Aβ-induced cell death were evaluated. NIa cleaved monomeric and oligomeric Aβ at a similar rate, whereas NEP only cleaved monomeric Aβ. Oligomeric Aβ-induced cytotoxicity and mitochondrial dysfunction were significantly ameliorated by NIa, but not by NEP. Endocytosed fluorescently-labeled Aβ localized to mitochondria, and this was significantly reduced by NIa, but not by NEP. These data suggest that NIa may exerts its protective roles by degrading Aβ and thus preventing mitochondrial deposition of Aβ.
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Affiliation(s)
- Baehyun Shin
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Hyejin Oh
- Bio Imaging and Cell Dynamics Research Center, School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Sang Min Park
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Hye-Eun Han
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Michael Ye
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Woo Keun Song
- Bio Imaging and Cell Dynamics Research Center, School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Woo Jin Park
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
- * E-mail:
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14
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Jha A, Narayan S, Udgaonkar JB, Krishnamoorthy G. Solvent-induced tuning of internal structure in a protein amyloid protofibril. Biophys J 2013; 103:797-806. [PMID: 22947941 DOI: 10.1016/j.bpj.2012.07.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 07/06/2012] [Accepted: 07/11/2012] [Indexed: 10/28/2022] Open
Abstract
An important goal in studies of protein aggregation is to obtain an understanding of the structural diversity that is characteristic of amyloid fibril and protofibril structures at the molecular level. In this study, what to our knowledge are novel assays based on time-resolved fluorescence anisotropy decay and dynamic quenching measurements of a fluorophore placed at different specific locations in the primary structure of a small protein, barstar, have been used to determine the extent to which the protein sequence participates in the structural core of protofibrils. The fluorescence measurements reveal the structural basis of how modulating solvent polarity results in the tuning of the protofibril conformation from a pair of parallel β-sheets in heat-induced protofibrils to a single parallel β-sheet in trifluorethanol-induced protofibrils. In trifluorethanol-induced protofibrils, the single β-sheet is shown to be built up from in-register β-strands formed by nearly the entire protein sequence, while in heat-induced protofibrils, the pair of β-sheets motif is built up from β-strands formed by only the last two-third of the protein sequence.
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Affiliation(s)
- Anjali Jha
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India
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15
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Binolfi A, Quintanar L, Bertoncini CW, Griesinger C, Fernández CO. Bioinorganic chemistry of copper coordination to alpha-synuclein: Relevance to Parkinson's disease. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2012.05.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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16
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Youmans KL, Wolozin B. TDP-43: a new player on the AD field? Exp Neurol 2012; 237:90-5. [PMID: 22691390 DOI: 10.1016/j.expneurol.2012.05.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 05/17/2012] [Accepted: 05/27/2012] [Indexed: 12/20/2022]
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17
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von Bernhardi R, Eugenín J. Alzheimer's disease: redox dysregulation as a common denominator for diverse pathogenic mechanisms. Antioxid Redox Signal 2012; 16:974-1031. [PMID: 22122400 DOI: 10.1089/ars.2011.4082] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia and a progressive neurodegeneration that appears to result from multiple pathogenic mechanisms (including protein misfolding/aggregation, involved in both amyloid β-dependent senile plaques and tau-dependent neurofibrillary tangles), metabolic and mitochondrial dysfunction, excitoxicity, calcium handling impairment, glial cell dysfunction, neuroinflammation, and oxidative stress. Oxidative stress, which could be secondary to several of the other pathophysiological mechanisms, appears to be a major determinant of the pathogenesis and progression of AD. The identification of oxidized proteins common for mild cognitive impairment and AD suggests that key oxidation pathways are triggered early and are involved in the initial progression of the neurodegenerative process. Abundant data support that oxidative stress, also considered as a main factor for aging, the major risk factor for AD, can be a common key element capable of articulating the divergent nature of the proposed pathogenic factors. Pathogenic mechanisms influence each other at different levels. Evidence suggests that it will be difficult to define a single-target therapy resulting in the arrest of progression or the improvement of AD deterioration. Since oxidative stress is present from early stages of disease, it appears as one of the main targets to be included in a clinical trial. Exploring the articulation of AD pathogenic mechanisms by oxidative stress will provide clues for better understanding the pathogenesis and progression of this dementing disorder and for the development of effective therapies to treat this disease.
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Affiliation(s)
- Rommy von Bernhardi
- Department of Neurology, Pontificia Universidad Católica de Chile, Santiago, Chile
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18
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Ding Y, Ko MH, Pehar M, Kotch F, Peters NR, Luo Y, Salamat SM, Puglielli L. Biochemical inhibition of the acetyltransferases ATase1 and ATase2 reduces β-secretase (BACE1) levels and Aβ generation. J Biol Chem 2012; 287:8424-33. [PMID: 22267734 PMCID: PMC3318698 DOI: 10.1074/jbc.m111.310136] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The cellular levels of β-site APP cleaving enzyme 1 (BACE1), the rate-limiting enzyme for the generation of the Alzheimer disease (AD) amyloid β-peptide (Aβ), are tightly regulated by two ER-based acetyl-CoA:lysine acetyltransferases, ATase1 and ATase2. Here we report that both acetyltransferases are expressed in neurons and glial cells, and are up-regulated in the brain of AD patients. We also report the identification of first and second generation compounds that inhibit ATase1/ATase2 and down-regulate the expression levels as well as activity of BACE1. The mechanism of action involves competitive and non-competitive inhibition as well as generation of unstable intermediates of the ATases that undergo degradation.
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Affiliation(s)
- Yun Ding
- Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
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19
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Tomidokoro Y, Rostagno A, Neubert TA, Lu Y, Rebeck GW, Frangione B, Greenberg SM, Ghiso J. Iowa variant of familial Alzheimer's disease: accumulation of posttranslationally modified AbetaD23N in parenchymal and cerebrovascular amyloid deposits. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 176:1841-54. [PMID: 20228223 PMCID: PMC2843474 DOI: 10.2353/ajpath.2010.090636] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/04/2009] [Indexed: 12/30/2022]
Abstract
Mutations within the amyloid-beta (Abeta) sequence, especially those clustered at residues 21-23, which are linked to early onset familial Alzheimer's disease (AD), are primarily associated with cerebral amyloid angiopathy (CAA). The basis for this predominant vascular amyloid burden and the differential clinical phenotypes of cerebral hemorrhage/stroke in some patients and dementia in others remain unknown. The AbetaD23N Iowa mutation is associated with progressive AD-like dementia, often without clinically manifested intracerebral hemorrhage. Neuropathologically, the disease is characterized by predominant preamyloid deposits, severe CAA, and abundant neurofibrillary tangles in the presence of remarkably few mature plaques. Biochemical analyses using a combination of immunoprecipitation, mass spectrometry, amino acid sequence, and Western blot analysis performed after sequential tissue extractions to separately isolate soluble components, preamyloid, and fibrillar amyloid species indicated that the Iowa deposits are complex mixtures of mutated and nonmutated Abeta molecules. These molecules exhibited various degrees of solubility, were highly heterogeneous at both the N- and C-termini, and showed partial aspartate isomerization at positions 1, 7, and 23. This collection of Abeta species-the Iowa brain Abeta peptidome-contained clear imprints of amyloid clearance mechanisms yet highlighted the unique neuropathological features shared by a non-Abeta cerebral amyloidosis, familial Danish dementia, in which neurofibrillary tangles coexist with extensive pre-amyloid deposition in the virtual absence of fibrillar lesions. These data therefore challenge the importance of neuritic plaques as the sole contributors for the development of dementia.
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Affiliation(s)
- Yasushi Tomidokoro
- Department of Pathology and Psychiatry, New York University School of Medicine, New York, NY 10016, USA
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20
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Machová E, Rudajev V, Smycková H, Koivisto H, Tanila H, Dolezal V. Functional cholinergic damage develops with amyloid accumulation in young adult APPswe/PS1dE9 transgenic mice. Neurobiol Dis 2010; 38:27-35. [PMID: 20053373 DOI: 10.1016/j.nbd.2009.12.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Revised: 12/03/2009] [Accepted: 12/26/2009] [Indexed: 10/20/2022] Open
Abstract
We investigated the functional characteristics of pre- and postsynaptic cholinergic transmission in APPswe/PS1dE9 double transgenic mice at a young age (7-10 weeks) before the onset of amyloid plaque formation and at adult age (5-6 months) at its onset. We compared brain slices from cerebral cortex and hippocampus with amyloid deposits to slices from striatum with no amyloid plaques by 6 months of age. In young transgenic mice we found no impairments of preformed and newly synthesized [(3)H]-ACh release, indicating intact releasing machinery and release turnover, respectively. Adult transgenic mice displayed a significant increase in preformed [(3)H]-ACh release in cortex but a decrease in hippocampus and striatum. The extent of presynaptic muscarinic autoregulation was unchanged. Evoked release of newly synthesized [(3)H]-ACh was significantly reduced in the cortex and hippocampus but unchanged in the striatum. Carbachol-induced G-protein activation in cortical membranes displayed decreased potency but normal efficacy in adult animals and no changes in young animals. These results indicate that functional pre- and postsynaptic cholinergic deficits are not present in APPswe/PS1dE9 transgenic mice before 10 weeks of age, but develop along with beta-amyloid accumulation in the brain.
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Affiliation(s)
- Eva Machová
- Institute of Physiology CAS, Vídenská 1083, 14220 Prague 4, Czech Republic
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21
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Maji SK, Ogorzalek Loo RR, Inayathullah M, Spring SM, Vollers SS, Condron MM, Bitan G, Loo JA, Teplow DB. Amino acid position-specific contributions to amyloid beta-protein oligomerization. J Biol Chem 2009; 284:23580-91. [PMID: 19567875 PMCID: PMC2749133 DOI: 10.1074/jbc.m109.038133] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Indexed: 12/21/2022] Open
Abstract
Understanding the structural and assembly dynamics of the amyloid beta-protein (Abeta) has direct relevance to the development of therapeutic agents for Alzheimer disease. To elucidate these dynamics, we combined scanning amino acid substitution with a method for quantitative determination of the Abeta oligomer frequency distribution, photo-induced cross-linking of unmodified proteins (PICUP), to perform "scanning PICUP." Tyr, a reactive group in PICUP, was substituted at position 1, 10, 20, 30, or 40 (for Abeta40) or 42 (for Abeta42). The effects of these substitutions were probed using circular dichroism spectroscopy, thioflavin T binding, electron microscopy, PICUP, and mass spectrometry. All peptides displayed a random coil --> alpha/beta --> beta transition, but substitution-dependent alterations in assembly kinetics and conformer complexity were observed. Tyr(1)-substituted homologues of Abeta40 and Abeta42 assembled the slowest and yielded unusual patterns of oligomer bands in gel electrophoresis experiments, suggesting oligomer compaction had occurred. Consistent with this suggestion was the observation of relatively narrow [Tyr(1)]Abeta40 fibrils. Substitution of Abeta40 at the C terminus decreased the population conformational complexity and substantially extended the highest order of oligomers observed. This latter effect was observed in both Abeta40 and Abeta42 as the Tyr substitution position number increased. The ability of a single substitution (Tyr(1)) to alter Abeta assembly kinetics and the oligomer frequency distribution suggests that the N terminus is not a benign peptide segment, but rather that Abeta conformational dynamics and assembly are affected significantly by the competition between the N and C termini to form a stable complex with the central hydrophobic cluster.
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Affiliation(s)
| | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine
- Molecular Biology Institute
| | | | | | | | | | - Gal Bitan
- From the Department of Neurology and
- Molecular Biology Institute
- Brain Research Institute, and
| | - Joseph A. Loo
- Department of Biological Chemistry, David Geffen School of Medicine
- Molecular Biology Institute
- Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095
| | - David B. Teplow
- From the Department of Neurology and
- Molecular Biology Institute
- Brain Research Institute, and
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22
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Reelin and apoE actions on signal transduction, synaptic function and memory formation. ACTA ACUST UNITED AC 2009; 4:259-70. [DOI: 10.1017/s1740925x09990184] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Low-density-lipoprotein receptors (LDLRs) are an evolutionarily ancient surface protein family with the ability to activate a diversity of extracellular signals across the cellular membrane in the adult central nervous system (CNS). Their intimate roles in modulating synaptic plasticity and their necessity in hippocampal-dependent learning and memory have only recently come to light. Two known LDLR ligands, specifically apolipoprotein E (apoE) and reelin, have been the most widely investigated in this regard. Most of our understanding of synaptic plasticity comes from investigation of both pre- and postsynaptic alterations. Therefore, it is interesting to note that neurons and glia that do not contribute to the synaptic junction in question can secrete signaling molecules that affect synaptic plasticity. Notably, reelin and apoE have been shown to modulate hippocampal long-term potentiation in general, and affect NMDA receptor and AMPA receptor regulation specifically. Furthermore, these receptors and signaling molecules have significant roles in neuronal degenerative diseases such as Alzheimer's disease. The recent production of recombinant proteins, knockout and transgenic mice for receptors and ligands and the development of human ApoE targeted replacement mice have significantly expanded our understanding of the roles LDLRs and their ligands have in certain disease states and the accompanying initiation of specific signaling pathways. This review describes the role LDLRs, apoE and reelin have in the regulation of hippocampal synaptic plasticity.
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Swerdlow RH, Khan SM. The Alzheimer's disease mitochondrial cascade hypothesis: an update. Exp Neurol 2009; 218:308-15. [PMID: 19416677 PMCID: PMC2710413 DOI: 10.1016/j.expneurol.2009.01.011] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 01/15/2009] [Indexed: 10/21/2022]
Abstract
In 2004 we proposed the mitochondrial cascade hypothesis of sporadic Alzheimer's disease (AD). Our hypothesis assumed sporadic and autosomal dominant AD are not etiologically homogeneous, considered evidence that AD pathology is not brain-limited, and incorporated aging theory. The mitochondrial cascade hypothesis asserted: (1) inheritance determines mitochondrial baseline function and durability; (2) mitochondrial durability influences how mitochondria change with age; and (3) when mitochondrial change reaches a threshold, AD histopathology and symptoms ensue. We now review the reasoning used to formulate the hypothesis, discuss pertinent interim data, and update its tenants. Readers are invited to consider the conceptual strengths and weaknesses of this hypothesis.
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Affiliation(s)
- Russell H Swerdlow
- Department of Neurology, University of Kansas School of Medicine, Kansas City, USA.
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24
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Sondag CM, Dhawan G, Combs CK. Beta amyloid oligomers and fibrils stimulate differential activation of primary microglia. J Neuroinflammation 2009; 6:1. [PMID: 19123954 PMCID: PMC2632990 DOI: 10.1186/1742-2094-6-1] [Citation(s) in RCA: 174] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Accepted: 01/05/2009] [Indexed: 12/31/2022] Open
Abstract
Background Beta amyloid (Aβ) peptides are the major constituents of the senile plaques present in Alzheimer's diseased brain. Pathogenesis has been associated with the aggregated form of the peptide as these fibrils are the conformation readily found in the plaques. However, recent studies have shown that the nonaggregated, soluble assemblies of Aβ have the potential to stimulate neuronal dysfunction and may play a prominent role in the pathogenesis of Alzheimer's disease. Methods Soluble, synthetic Aβ1–42 oligomers were prepared producing mainly dimer-trimer conformations as assessed by SDS-PAGE. Similar analysis demonstrated fibril preparations to produce large insoluble aggregates unable to migrate out of the stacking portion of the gels. These peptide preparations were used to stimulate primary murine microglia and cortical neuron cultures. Microglia were analyzed for changes in signaling response and secretory phenotype via Western analysis and ELISA. Viability was examined by quantifying lactate dehydrogenase release from the cultures. Results Aβ oligomers and fibrils were used to stimulate microglia for comparison. Both the oligomers and fibrils stimulated proinflammatory activation of primary microglia but the specific conformation of the peptide determined the activation profile. Oligomers stimulated increased levels of active, phosphorylated Lyn and Syk kinase as well as p38 MAP kinase compared to fibrils. Moreover, oligomers stimulated a differential secretory profile for interleukin 6, monocyte chemoattractant protein-1 and keratinocyte chemoattractant when compared to fibrils. Finally, soluble oligomers stimulated death of cultured cortical neurons that was exacerbated by the presence of microglia. Conclusion These data suggest that fibrils and oligomers stimulate unique signaling responses in microglia leading to discrete secretory changes and effects on neuron survival. This suggests that inflammation changes during disease may be the consequence of unique peptide-stimulated events and each conformation may represent an individual anti-inflammatory therapeutic target.
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Affiliation(s)
- Cindy M Sondag
- Department of Pharmacology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA.
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25
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Rodziewicz-Motowidło S, Czaplewska P, Sikorska E, Spodzieja M, Kołodziejczyk AS. The Arctic mutation alters helix length and type in the 11-28 beta-amyloid peptide monomer-CD, NMR and MD studies in an SDS micelle. J Struct Biol 2008; 164:199-209. [PMID: 18765285 DOI: 10.1016/j.jsb.2008.07.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 07/11/2008] [Accepted: 07/29/2008] [Indexed: 11/30/2022]
Abstract
The beta-amyloid (Abeta) is the major peptide constituent of neuritic plaques in Alzheimer's disease, and its aggregation is believed to play a central role in the pathogenesis of the disease. Naturally occurring mutations resulting in changes in the Abeta sequence (pos. 21-23) are associated with familial Alzheimer's-like diseases with extensive cerebrovascular pathology. It has been demonstrated that such mutations alter the aggregation ability of Abeta and its neurotoxicity. Among the five mutations at positions 21-23 there is one with distinct clinical characteristics and a potentially distinct pathogenic mechanism-the Arctic (E22G) mutation. We have examined the structures of fragment 11-28 of the native peptide and its E22G variant. This fragment was chosen because it has been shown to be a good model for conformational and aggregation studies as it contains the hydrophobic core responsible for aggregation and the residues critical to alpha-secretase cleavage of APP. The detailed structure of the two peptides was determined using CD, 2D NMR and molecular dynamics techniques under water-SDS micelle conditions. Our studies indicated the existence of partially alpha- and 3(10)-helical conformations in the native and mutated peptide, respectively.
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26
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Rahimi F, Shanmugam A, Bitan G. Structure-function relationships of pre-fibrillar protein assemblies in Alzheimer's disease and related disorders. Curr Alzheimer Res 2008; 5:319-41. [PMID: 18537546 DOI: 10.2174/156720508784533358] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Several neurodegenerative diseases, including Alzheimer's, Parkinson's, Huntington's and prion diseases, are characterized pathognomonically by the presence of intra- and/or extracellular lesions containing proteinaceous aggregates, and by extensive neuronal loss in selective brain regions. Related non-neuropathic systemic diseases, e.g., light-chain and senile systemic amyloidoses, and other organ-specific diseases, such as dialysis-related amyloidosis and type-2 diabetes mellitus, also are characterized by deposition of aberrantly folded, insoluble proteins. It is debated whether the hallmark pathologic lesions are causative. Substantial evidence suggests that these aggregates are the end state of aberrant protein folding whereas the actual culprits likely are transient, pre-fibrillar assemblies preceding the aggregates. In the context of neurodegenerative amyloidoses, the proteinaceous aggregates may eventuate as potentially neuroprotective sinks for the neurotoxic, oligomeric protein assemblies. The pre-fibrillar, oligomeric assemblies are believed to initiate the pathogenic mechanisms that lead to synaptic dysfunction, neuronal loss, and disease-specific regional brain atrophy. The amyloid beta-protein (Abeta), which is believed to cause Alzheimer's disease (AD), is considered an archetypal amyloidogenic protein. Intense studies have led to nominal, functional, and structural descriptions of oligomeric Abeta assemblies. However, the dynamic and metastable nature of Abeta oligomers renders their study difficult. Different results generated using different methodologies under different experimental settings further complicate this complex area of research and identification of the exact pathogenic assemblies in vivo seems daunting. Here we review structural, functional, and biological experiments used to produce and study pre-fibrillar Abeta assemblies, and highlight similar studies of proteins involved in related diseases. We discuss challenges that contemporary researchers are facing and future research prospects in this demanding yet highly important field.
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Affiliation(s)
- F Rahimi
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095-7334, USA
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27
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Scheinost J, Wang H, Boldt G, Offer J, Wentworth P. Cholesterolseco-Sterol-Induced Aggregation of Methylated Amyloid-β Peptides—Insights into Aldehyde-Initiated Fibrillization of Amyloid-β. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200705922] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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28
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Scheinost J, Wang H, Boldt G, Offer J, Wentworth P. Cholesterolseco-Sterol-Induced Aggregation of Methylated Amyloid-β PeptidesâInsights into Aldehyde-Initiated Fibrillization of Amyloid-β. Angew Chem Int Ed Engl 2008; 47:3919-22. [DOI: 10.1002/anie.200705922] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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29
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Rodziewicz-Motowidło S, Juszczyk P, Kołodziejczyk AS, Sikorska E, Skwierawska A, Oleszczuk M, Grzonka Z. Conformational solution studies of the SDS micelle-bound 11-28 fragment of two Alzheimer's β-amyloid variants (E22K and A21G) using CD, NMR, and MD techniques. Biopolymers 2007; 87:23-39. [PMID: 17534931 DOI: 10.1002/bip.20768] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The beta-amyloid (Abeta) is the major peptide constituent of neuritic plaques in Alzheimer's disease (AD) and its aggregation is believed to play a central role in the pathogenesis of the disease. Naturally occurring mutations resulting in changes in the Abeta sequence (pos. 21-23) are associated with familial AD-like diseases with extensive cerebrovascular pathology. It was proved that the mutations alter the aggregation ability of Abeta and its neurotoxicity. Among five mutations at positions 21-23 there are two mutations with distinct clinical characteristics and potentially distinct pathogenic mechanism-the Italian (E22K) and the Flemish (A21G) mutations. In our studies we have examined the structures of the 11-28 fragment of the Italian and Flemish Abeta variants. The fragment was chosen because it has been shown to be the most important for amyloid fibril formation. The detailed structure of both variants Abeta(11-28) was determined using CD, 2D NMR, and molecular dynamics techniques under water-SDS micelle conditions. The NMR analysis revealed two distinct sets of proton resonances for the peptides. The studies of both peptides pointed out the existence of well-defined alpha-helical conformation in the Italian mutant, whereas the Flemish was found to be unstructured with the possibility of a bent structure in the central part of the peptide.
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30
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Englund H, Sehlin D, Johansson AS, Nilsson LNG, Gellerfors P, Paulie S, Lannfelt L, Pettersson FE. Sensitive ELISA detection of amyloid-beta protofibrils in biological samples. J Neurochem 2007; 103:334-45. [PMID: 17623042 DOI: 10.1111/j.1471-4159.2007.04759.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Amyloid-beta (Abeta) protofibrils are known intermediates of the in vitro Abeta aggregation process and the protofibrillogenic Arctic mutation (APPE693G) provides clinical support for a pathogenic role of Abeta protofibrils in Alzheimer's disease (AD). To verify their in vivo relevance and to establish a quantitative Abeta protofibril immunoassay, Abeta conformation dependent monoclonal antibodies were generated. One of these antibodies, mAb158 (IgG2a), was used in a sandwich ELISA to specifically detect picomolar concentrations of Abeta protofibrils without interference from Abeta monomers or the amyloid precursor protein (APP). The specificity and biological significance of this ELISA was demonstrated using cell cultures and transgenic mouse models expressing human APP containing the Swedish mutation (APPKN670/671ML), or the Swedish and Arctic mutation in combination. The mAb158 sandwich ELISA analysis revealed presence of Abeta protofibrils in both cell and animal models, proving that Abeta protofibrils are formed not only in vitro, but also in vivo. Furthermore, elevated Abeta protofibril levels in the Arctic-Swedish samples emphasize the usefulness of the Arctic mutation as a model of enhanced protofibril formation. This assay provides a novel tool for investigating the role of Abeta protofibrils in AD and has the potential of becoming an important diagnostic assay.
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Affiliation(s)
- Hillevi Englund
- Department of Public Health/Molecular Geriatrics, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
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31
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Heo C, Chang KA, Choi HS, Kim HS, Kim S, Liew H, Kim JA, Yu E, Ma J, Suh YH. Effects of the monomeric, oligomeric, and fibrillar Abeta42 peptides on the proliferation and differentiation of adult neural stem cells from subventricular zone. J Neurochem 2007; 102:493-500. [PMID: 17403034 DOI: 10.1111/j.1471-4159.2007.04499.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The incidence of amyloid plaques, composed mainly of beta-amyloid peptides (Abeta), does not correlate well with the severity of neurodegeneration in patients with Alzheimer's disease (AD). The effects of Abeta(42) on neurons or neural stem cells (NSCs) in terms of the aggregated form remain controversial. We prepared three forms of oligomeric, fibrillar, and monomeric Abeta(42) peptides and investigated their effects on the proliferation and neural differentiation of adult NSCs, according to the degree of aggregation or concentration. A low micromolar concentration (1 micromol/L) of oligomeric Abeta(42) increased the proliferation of adult NSCs remarkably in a neurosphere assay. It also enhanced the neuronal differentiation of adult NSCs and their ability to migrate. These results provide us with valuable information regarding the effects of Abeta(42) on NSCs in the brains of patients with AD.
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Affiliation(s)
- Chaejeong Heo
- Department of Pharmacology, College of Medicine, National Creative Research Initiative Center for Alzheimer's Dementia, Neuroscience Research Institute, MRC, Seoul National University, Seoul, South Korea
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32
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Machová E, Jakubík J, Michal P, Oksman M, Iivonen H, Tanila H, Dolezal V. Impairment of muscarinic transmission in transgenic APPswe/PS1dE9 mice. Neurobiol Aging 2006; 29:368-78. [PMID: 17140703 DOI: 10.1016/j.neurobiolaging.2006.10.029] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 09/20/2006] [Accepted: 10/30/2006] [Indexed: 02/07/2023]
Abstract
We assessed the integrity of cholinergic neurotransmission in parietal cortex of young adult (7 months) and aged (17 months) transgenic APPswe/PS1dE9 female mice compared to littermate controls. Choline acetyltransferase and acetylcholinesterase activity declined age-dependently in both genotypes, whereas both age- and genotype-dependent decline was found in butyrylcholinesterase activity, vesicular acetylcholine transporter density, muscarinic receptors and carbachol stimulated binding of GTP gamma S in membranes as a functional indicator of muscarinic receptor coupling to G-proteins. Notably, vesicular acetylcholine transporter levels and muscarinic receptor-G-protein coupling were impaired in transgenic mice already at the age of 7 months compared to wild type littermates. Thus, brain amyloid accumulation in this mouse model is accompanied by a serious deterioration of muscarinic transmission already before the mice manifest significant cognitive deficits.
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Affiliation(s)
- E Machová
- Department of Neurochemistry, Institute of Physiology CAS, Vídenská 1083, 14220 Prague 4, Czech Republic
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33
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Rebeck GW, LaDu MJ, Estus S, Bu G, Weeber EJ. The generation and function of soluble apoE receptors in the CNS. Mol Neurodegener 2006; 1:15. [PMID: 17062143 PMCID: PMC1635701 DOI: 10.1186/1750-1326-1-15] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Accepted: 10/24/2006] [Indexed: 01/11/2023] Open
Abstract
More than a decade has passed since apolipoprotein E4 (APOE-ε4) was identified as a primary risk factor for Alzheimer 's disease (AD), yet researchers are even now struggling to understand how the apolipoprotein system integrates into the puzzle of AD etiology. The specific pathological actions of apoE4, methods of modulating apolipoprotein E4-associated risk, and possible roles of apoE in normal synaptic function are still being debated. These critical questions will never be fully answered without a complete understanding of the life cycle of the apolipoprotein receptors that mediate the uptake, signaling, and degradation of apoE. The present review will focus on apoE receptors as modulators of apoE actions and, in particular, explore the functions of soluble apoE receptors, a field almost entirely overlooked until now.
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Affiliation(s)
- G William Rebeck
- Department of Neuroscience, Georgetown University, Washington DC, USA
| | - Mary Jo LaDu
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, USA
| | - Steven Estus
- Department of Physiology, University of Kentucky, Lexington, USA
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, USA
| | - Guojun Bu
- Department of Pediatrics, Washington University, St. Louis, USA
- Department of Cell Biology and Physiology, Washington University, St. Louis, USA
- Hope Center for Neurological Disorders, Washington University, St. Louis, USA
| | - Edwin J Weeber
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, USA
- Department of Pharmacology, Vanderbilt University, Nashville, USA
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, USA
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Characterization of Interactions Between Misfolding Proteins and Molecular Chaperones by NMR Spectroscopy. Top Curr Chem (Cham) 2006. [DOI: 10.1007/128_066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Narayanan S, Kamps B, Boelens WC, Reif B. αB-crystallin competes with Alzheimer's disease β-amyloid peptide for peptide-peptide interactions and induces oxidation of Abeta-Met35. FEBS Lett 2006; 580:5941-6. [PMID: 17046756 DOI: 10.1016/j.febslet.2006.09.063] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 08/17/2006] [Accepted: 09/22/2006] [Indexed: 01/28/2023]
Abstract
Alzheimer's disease (AD) is associated with plaque deposition in the brain of AD patients. The major component of the aggregate is a 39-42 long peptide termed beta-amyloid (Abeta). Except for Abeta, plaques contain several other components which co-precipitate together with Abeta. One such component is the small heat shock protein (sHSP) alphaB-crystallin. Instead of preventing the cell from the neurotoxicity of Abeta, alphaB-crystallin induces an increased neurotoxicity. We find - using solution state NMR spectroscopy - that alphaB-crystallin competes efficiently for Abeta monomer-monomer interactions. Interactions between Abeta and alphaB-crystallin involve the hydrophobic core residues 17-21 as well as residues 31-32 of Abeta, and thus the same chemical groups which are important for Abeta aggregation. In the presence of alphaB-crystallin, Met35 in Abeta becomes efficiently oxidized. In order to quantify the redox properties of the different complexes consisting of Abeta/alphaB-crystallin/copper, we suggest an NMR assay which allows to estimate the electrochemical properties indirectly by monitoring the rate of glutathion (GSH) auto-oxidation. The oxidation of the side chain Met35 in Abeta might account for the increased neurotoxicity and the inability of Abeta to form fibrillar structures, which has been observed previously in the presence of alphaB-crystallin [Stege, G.J. et al. (1999) The molecular chaperone alphaB-crystallin enhances amyloid-beta neurotoxicity. Biochem. Biophys. Res. Commun. 262, 152-156.].
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Affiliation(s)
- Saravanakumar Narayanan
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse, 10, 13125 Berlin, Germany
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36
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Monien BH, Apostolova LG, Bitan G. Early diagnostics and therapeutics for Alzheimer's disease--how early can we get there? Expert Rev Neurother 2006; 6:1293-306. [PMID: 17009917 PMCID: PMC2715564 DOI: 10.1586/14737175.6.9.1293] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Alzheimer's disease (AD) is a major threat for the rapidly aging world population. AD is the leading cause of dementia and a major cause of death in developed countries. The disease puts a tremendous practical, emotional and financial burden on individuals and governments. Clinicians and researchers in the AD field face great challenges: the pathophysiological processes that cause AD are not well understood, definite diagnosis of AD requires autopsy, and therapeutic options are limited to treating the symptoms rather than the cause of the disease. Nevertheless, new insights into the earliest events that lead to development of AD increase hope that reliable diagnostics and efficacious therapies may emerge.
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Affiliation(s)
- Bernhard H Monien
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, Neuroscience Research Building 1, Room 455, 635 Charles E. Young Drive South, Los Angeles, CA 90095-7334, USA, Tel.: +1 310 206 2300, Fax: +1 310 206 1700,
| | - Liana G Apostolova
- Tichi Wilkerson-Kassel Dementia Scholar, UCLA Alzheimer’s Disease Center, 10911 Weyburn Ave., 2nd Floor, Los Angeles, CA 90095-7226, USA, Tel.: +1 310 794 2551, Fax: +1 310 794 3148,
| | - Gal Bitan
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, Neuroscience Research Building 1, Room 451, 635 Charles E. Young Drive South, Los Angeles, CA 90095-7334, USA, Tel.: +1 310 206 2082, Fax: +1 310 206 1700,
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37
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Knobloch M, Konietzko U, Krebs DC, Nitsch RM. Intracellular Abeta and cognitive deficits precede beta-amyloid deposition in transgenic arcAbeta mice. Neurobiol Aging 2006; 28:1297-306. [PMID: 16876915 DOI: 10.1016/j.neurobiolaging.2006.06.019] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2006] [Revised: 06/07/2006] [Accepted: 06/15/2006] [Indexed: 12/31/2022]
Abstract
The brain pathology of Alzheimer's disease is characterized by abnormally aggregated Abeta in extracellular beta-amyloid plaques and along blood vessel walls, but the relation to intracellular Abeta remains unclear. To address the role of intracellular Abeta deposition in vivo, we expressed human APP with the combined Swedish and Arctic mutations in mice (arcAbeta mice). Intracellular punctate deposits of Abeta occurred concomitantly with robust cognitive impairments at the age of 6 months before the onset of beta-amyloid plaque formation and cerebral beta-amyloid angiopathy. beta-Amyloid plaques from arcAbeta mice had distinct dense-core morphologies with blood vessels appearing as seeding origins, suggesting reduced clearance of Abeta across blood vessels in arcAbeta mice. The co-incidence of intracellular Abeta deposits with behavioral deficits support an early role of intracellular Abeta in the pathophysiological cascade leading to beta-amyloid formation and functional impairment.
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Affiliation(s)
- Marlen Knobloch
- Division of Psychiatry Research, University of Zurich, August Forel-Str. 1, 8008 Zurich, Switzerland
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38
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Ghiso J, Rostagno A, Tomidokoro Y, Lashley T, Bojsen-Møller M, Braendgaard H, Plant G, Holton J, Lal R, Revesz T, Frangione B. Genetic alterations of the BRI2 gene: familial British and Danish dementias. Brain Pathol 2006; 16:71-9. [PMID: 16612984 PMCID: PMC8095812 DOI: 10.1111/j.1750-3639.2006.tb00563.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Classic arguments sustaining the importance of amyloid in the pathogenesis of dementia are usually centered on amyloid beta (Abeta) and its role in neuronal loss characteristic of Alzheimer disease, the most common form of human cerebral amyloidosis. Two non-Abeta cerebral amyloidoses, familial British and Danish dementias, share many aspects of Alzheimer disease, including the presence of neurofibrillary tangles, parenchymal pre-amyloid and amyloid deposits, cerebral amyloid angiopathy, and a widespread inflammatory response. Both early-onset conditions are linked to specific mutations in the BRI2 gene, causing the generation of longer-than-normal protein products and the release of 2 de novo created peptides ABri and ADan, the main components of amyloid fibrils in these inherited dementias. Although the molecular mechanisms and signal transduction pathways elicited by the amyloid deposits and their relation to cognitive impairment remain to be clarified, new evidence indicates that, independent of the differences in their primary structures, Abeta, ABri, and ADan subunits are able to form morphologically compatible ion-channel-like structures and elicit single ion-channel currents in reconstituted lipid membranes. These findings reaffirm the notion that non-Abeta amyloidosis constitute suitable alternative models to study the role of amyloid deposition in the mechanism of neuronal cell death.
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Affiliation(s)
- J Ghiso
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
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39
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Lazo ND, Grant MA, Condron MC, Rigby AC, Teplow DB. On the nucleation of amyloid beta-protein monomer folding. Protein Sci 2005; 14:1581-96. [PMID: 15930005 PMCID: PMC2253382 DOI: 10.1110/ps.041292205] [Citation(s) in RCA: 273] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Neurotoxic assemblies of the amyloid beta-protein (Abeta) have been linked strongly to the pathogenesis of Alzheimer's disease (AD). Here, we sought to monitor the earliest step in Abeta assembly, the creation of a folding nucleus, from which oligomeric and fibrillar assemblies emanate. To do so, limited proteolysis/mass spectrometry was used to identify protease-resistant segments within monomeric Abeta(1-40) and Abeta(1-42). The results revealed a 10-residue, protease-resistant segment, Ala21-Ala30, in both peptides. Remarkably, the homologous decapeptide, Abeta(21-30), displayed identical protease resistance, making it amenable to detailed structural study using solution-state NMR. Structure calculations revealed a turn formed by residues Val24-Lys28. Three factors contribute to the stability of the turn, the intrinsic propensities of the Val-Gly-Ser-Asn and Gly-Ser-Asn-Lys sequences to form a beta-turn, long-range Coulombic interactions between Lys28 and either Glu22 or Asp23, and hydrophobic interaction between the isopropyl and butyl side chains of Val24 and Lys28, respectively. We postulate that turn formation within the Val24-Lys28 region of Abeta nucleates the intramolecular folding of Abeta monomer, and from this step, subsequent assembly proceeds. This model provides a mechanistic basis for the pathologic effects of amino acid substitutions at Glu22 and Asp23 that are linked to familial forms of AD or cerebral amyloid angiopathy. Our studies also revealed that common C-terminal peptide segments within Abeta(1-40) and Abeta(1-42) have distinct structures, an observation of relevance for understanding the strong disease association of increased Abeta(1-42) production. Our results suggest that therapeutic approaches targeting the Val24-Lys28 turn or the Abeta(1-42)-specific C-terminal fold may hold promise.
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Affiliation(s)
- Noel D Lazo
- Department of Neurology, David Geffen School of Medicine at UCLA, 710 Westwood Plaza (Reed C119A), Los Angeles, CA 90095, USA
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40
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Tomidokoro Y, Lashley T, Rostagno A, Neubert TA, Bojsen-Møller M, Braendgaard H, Plant G, Holton J, Frangione B, Révész T, Ghiso J. Familial Danish dementia: co-existence of Danish and Alzheimer amyloid subunits (ADan AND A{beta}) in the absence of compact plaques. J Biol Chem 2005; 280:36883-94. [PMID: 16091362 DOI: 10.1074/jbc.m504038200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Familial Danish dementia is an early onset autosomal dominant neurodegenerative disorder linked to a genetic defect in the BRI2 gene and clinically characterized by dementia and ataxia. Cerebral amyloid and preamyloid deposits of two unrelated molecules (Danish amyloid (ADan) and beta-amyloid (Abeta)), the absence of compact plaques, and neurofibrillary degeneration indistinguishable from that observed in Alzheimer disease (AD) are the main neuropathological features of the disease. Biochemical analysis of extracted amyloid and preamyloid species indicates that as the solubility of the deposits decreases, the heterogeneity and complexity of the extracted peptides exponentially increase. Nonfibrillar deposits were mainly composed of intact ADan-(1-34) and its N-terminally modified (pyroglutamate) counterpart together with Abeta-(1-42) and Abeta-(4-42) in approximately 1:1 mixture. The post-translational modification, glutamate to pyroglutamate, was not present in soluble circulating ADan. In the amyloid fractions, ADan was heavily oligomerized and highly heterogeneous at the N and C terminus, and, when intact, its N terminus was post-translationally modified (pyroglutamate), whereas Abeta was mainly Abeta-(4-42). In all cases, the presence of Abeta-(X-40) was negligible, a surprising finding in view of the prevalence of Abeta40 in vascular deposits observed in sporadic and familial AD, Down syndrome, and normal aging. Whether the presence of the two amyloid subunits is imperative for the disease phenotype or just reflects a conformational mimicry remains to be elucidated; nonetheless, a specific interaction between ADan oligomers and Abeta molecules was demonstrated in vitro by ligand blot analysis using synthetic peptides. The absence of compact plaques in the presence of extensive neuro fibrillar degeneration strongly suggests that compact plaques, fundamental lesions for the diagnosis of AD, are not essential for the mechanism of dementia.
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Affiliation(s)
- Yasushi Tomidokoro
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
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41
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White JA, Manelli AM, Holmberg KH, Van Eldik LJ, Ladu MJ. Differential effects of oligomeric and fibrillar amyloid-β1–42 on astrocyte-mediated inflammation. Neurobiol Dis 2005; 18:459-65. [PMID: 15755672 DOI: 10.1016/j.nbd.2004.12.013] [Citation(s) in RCA: 164] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Revised: 10/19/2004] [Accepted: 12/22/2004] [Indexed: 12/31/2022] Open
Abstract
Activated glia, as a result of chronic inflammation, are associated with amyloid-beta peptide (Abeta) deposits in the brain of Alzheimer's disease (AD) patients. In vitro, glia are activated by Abeta inducing secretion of pro-inflammatory molecules. Recent studies have focused on soluble oligomers (or protofibrils) of Abeta as the toxic species in AD. In the present study, using rat astrocyte cultures, oligomeric Abeta induced initial high levels of IL-1beta decreasing over time and, in contrast, fibrillar Abeta increased IL-1beta levels over time. In addition, oligomeric Abeta, but not fibrillar Abeta, induced high levels of iNOS, NO, and TNF-alpha. Our results suggest that oligomers induced a profound, early inflammatory response, whereas fibrillar Abeta showed less increase of pro-inflammatory molecules, consistent with a more chronic form of inflammation.
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Affiliation(s)
- Jill A White
- Department of Medicine, Division of Geriatrics, Evanston Northwestern Healthcare Research Institute, Evanston, IL 60201, USA
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42
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Abstract
During the course of Alzheimer's disease (AD), neurons undergo extensive remodeling, contributing to the loss of function observed in the disease. Many brain regions in patients with AD show changes in axonal and dendritic fields, dystrophic neurites, synapse loss, and neuron loss. Accumulation of amyloid-beta protein, a pathological hallmark of the disease, contributes to many of these alterations of neuronal structure. Areas of the brain displaying a high degree of plasticity are particularly vulnerable to degeneration in Alzheimer's disease. This article describes neuronal changes that occur in AD, reviews evidence that amyloid-beta contributes to these changes, and finally discusses the recovery of amyloid-induced changes in the brains of transgenic mice, lending hope to the idea that therapeutic strategies which reduce amyloid-beta production will lead to functional recovery in patients with AD.
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Affiliation(s)
- Tara L Spires
- Department of Neurology, Alzheimer's Disease Research Laboratory, Massachusetts General Hospital, Charlestown, MA 02129, USA.
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43
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Päiviö A, Nordling E, Kallberg Y, Thyberg J, Johansson J. Stabilization of discordant helices in amyloid fibril-forming proteins. Protein Sci 2004; 13:1251-9. [PMID: 15096631 PMCID: PMC2286751 DOI: 10.1110/ps.03442404] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Several proteins and peptides that can convert from alpha-helical to beta-sheet conformation and form amyloid fibrils, including the amyloid beta-peptide (Abeta) and the prion protein, contain a discordant alpha-helix that is composed of residues that strongly favor beta-strand formation. In their native states, 37 of 38 discordant helices are now found to interact with other protein segments or with lipid membranes, but Abeta apparently lacks such interactions. The helical propensity of the Abeta discordant region (K16LVFFAED23) is increased by introducing V18A/F19A/F20A replacements, and this is associated with reduced fibril formation. Addition of the tripeptide KAD or phospho-L-serine likewise increases the alpha-helical content of Abeta(12-28) and reduces aggregation and fibril formation of Abeta(1-40), Abeta(12-28), Abeta(12-24), and Abeta(14-23). In contrast, tripeptides with all-neutral, all-acidic or all-basic side chains, as well as phosphoethanolamine, phosphocholine, and phosphoglycerol have no significant effects on Abeta secondary structure or fibril formation. These data suggest that in free Abeta, the discordant alpha-helix lacks stabilizing interactions (likely as a consequence of proteolytic removal from a membrane-associated precursor protein) and that stabilization of this helix can reduce fibril formation.
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Affiliation(s)
- Anna Päiviö
- Department of Molecular Biosciences, Swedish University of Agricultural Sciences, The Biomedical Centre, S-751 23 Uppsala, Sweden
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44
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Klein WL, Stine WB, Teplow DB. Small assemblies of unmodified amyloid beta-protein are the proximate neurotoxin in Alzheimer's disease. Neurobiol Aging 2004; 25:569-80. [PMID: 15172732 DOI: 10.1016/j.neurobiolaging.2004.02.010] [Citation(s) in RCA: 360] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2003] [Revised: 02/04/2004] [Accepted: 02/12/2004] [Indexed: 11/22/2022]
Abstract
Pioneering work in the 1950s by Christian Anfinsen on the folding of ribonuclease has shown that the primary structure of a protein "encodes" all of the information necessary for a nascent polypeptide to fold into its native, physiologically active, three-dimensional conformation (for his classic review, see [Science 181 (1973) 223]). In Alzheimer's disease (AD), the amyloid beta-protein (Abeta) appears to play a seminal role in neuronal injury and death. Recent data have suggested that the proximate effectors of neurotoxicity are oligomeric Abeta assemblies. A fundamental question, of relevance both to the development of therapeutic strategies for AD and to understanding basic laws of protein folding, is how Abeta assembly state correlates with biological activity. Evidence suggests, as argued by Anfinsen, that the formation of toxic Abeta structures is an intrinsic feature of the peptide's amino acid sequence-one requiring no post-translational modification or invocation of peptide-associated enzymatic activity.
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Affiliation(s)
- W L Klein
- Department of Neurobiology and Physiology, Cognitive Neurology and Alzheimer's Disease Center, Northwestern University Institute for Neuroscience, Evanston, IL, USA
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45
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Ghiso J, Shayo M, Calero M, Ng D, Tomidokoro Y, Gandy S, Rostagno A, Frangione B. Systemic catabolism of Alzheimer's Abeta40 and Abeta42. J Biol Chem 2004; 279:45897-908. [PMID: 15322125 DOI: 10.1074/jbc.m407668200] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
To better understand the physiologic excretion and/or catabolism of circulating peripheral amyloid beta (Abeta), we labeled human Abeta40 (monomeric, with predominant unordered structure) and Abeta42 (mixture of monomers and oligomers in approximately 50:50 ratio, rich in beta-sheet conformation) with either Na(125)I or (125)I-tyramine cellobiose, also known as the cell-trapping ligand procedure, testing their blood clearance and organ uptake in B6SJLF1/J mice. Irrespective of the labeling protocol, the peptide conformation, and the degree of oligomerization, both Abeta40 and Abeta42 showed a short half-life of 2.5-3.0 min. The liver was the major organ responsible for plasma clearance, accounting for >60% of the peptide uptake, followed by the kidney. In vivo, hepatocytes captured >90% of the radiolabeled peptides which, after endocytosis, were preferentially catabolized and excreted into the bile. Biliary excretion of intact as well as partially degraded Abeta species became obviously relevant at doses above 10 microg. The use of biotin-labeled Abeta allowed the visualization of the interaction with HepG2 cells in culture, whereas competitive inhibition experiments with unlabeled Abeta demonstrated the specificity of the binding. The capability of the liver to uptake, catabolize, and excrete large doses of Abeta, several orders of magnitude above its physiologic concentration, may explain not only the femtomolar plasma levels of Abeta but the little fluctuation observed with age and disease stages.
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Affiliation(s)
- Jorge Ghiso
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA.
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46
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Herzig MC, Winkler DT, Burgermeister P, Pfeifer M, Kohler E, Schmidt SD, Danner S, Abramowski D, Stürchler-Pierrat C, Bürki K, van Duinen SG, Maat-Schieman MLC, Staufenbiel M, Mathews PM, Jucker M. Aβ is targeted to the vasculature in a mouse model of hereditary cerebral hemorrhage with amyloidosis. Nat Neurosci 2004; 7:954-60. [PMID: 15311281 DOI: 10.1038/nn1302] [Citation(s) in RCA: 290] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Accepted: 07/12/2004] [Indexed: 11/09/2022]
Abstract
The E693Q mutation in the amyloid beta precursor protein (APP) leads to cerebral amyloid angiopathy (CAA), with recurrent cerebral hemorrhagic strokes and dementia. In contrast to Alzheimer disease (AD), the brains of those affected by hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D) show few parenchymal amyloid plaques. We found that neuronal overexpression of human E693Q APP in mice (APPDutch mice) caused extensive CAA, smooth muscle cell degeneration, hemorrhages and neuroinflammation. In contrast, overexpression of human wild-type APP (APPwt mice) resulted in predominantly parenchymal amyloidosis, similar to that seen in AD. In APPDutch mice and HCHWA-D human brain, the ratio of the amyloid-beta40 peptide (Abeta40) to Abeta42 was significantly higher than that seen in APPwt mice or AD human brain. Genetically shifting the ratio of AbetaDutch40/AbetaDutch42 toward AbetaDutch42 by crossing APPDutch mice with transgenic mice producing mutated presenilin-1 redistributed the amyloid pathology from the vasculature to the parenchyma. The understanding that different Abeta species can drive amyloid pathology in different cerebral compartments has implications for current anti-amyloid therapeutic strategies. This HCHWA-D mouse model is the first to develop robust CAA in the absence of parenchymal amyloid, highlighting the key role of neuronally produced Abeta to vascular amyloid pathology and emphasizing the differing roles of Abeta40 and Abeta42 in vascular and parenchymal amyloid pathology.
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Affiliation(s)
- Martin C Herzig
- Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, D-72076 Tübingen, Germany
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47
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Bitan G, Teplow DB. Rapid photochemical cross-linking--a new tool for studies of metastable, amyloidogenic protein assemblies. Acc Chem Res 2004; 37:357-64. [PMID: 15196045 DOI: 10.1021/ar000214l] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Amyloidoses comprise a class of diseases characterized pathologically by the presence of deposits of fibrillar, aberrantly folded proteins, known as amyloids. Historically, these deposits were considered the key factors causing disease. However, recent evidence suggests that soluble protein oligomers, which are precursors for amyloid fibrils, are the primary toxic effectors responsible for the disease process. Understanding the mechanism by which these oligomers exert their toxicity requires knowledge of the structure, kinetics, and thermodynamics of their formation and conversion into larger assemblies. Such studies have been difficult due to the metastable nature of the oligomers. For the amyloid beta-protein (Abeta), a consensus about the size and relative abundance of small oligomers has not been achieved. We describe here the application of the method Photoinduced Cross-Linking of Unmodified Proteins (PICUP) to the study of Abeta oligomerization. This approach distinguishes oligomerization patterns of amyloidogenic and nonamyloidogenic proteins, allows quantification of each component in oligomer mixtures, and provides a means of correlating primary structure modifications with assembly characteristics. PICUP thus is a powerful tool for the investigation of small, metastable protein oligomers. The method provides essential insights into the factors that control the assembly of pathogenic protein oligomers, facilitating efforts toward the development of therapeutic agents.
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Affiliation(s)
- Gal Bitan
- Center for Neurologic Diseases, Brigham and Women's Hospital and Department of Neurology, Harvard Medical School, Boston, MA 02115, USA.
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48
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Srinivasan R, Jones EM, Liu K, Ghiso J, Marchant RE, Zagorski MG. pH-dependent amyloid and protofibril formation by the ABri peptide of familial British dementia. J Mol Biol 2003; 333:1003-23. [PMID: 14583196 DOI: 10.1016/j.jmb.2003.09.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The ABri is a 34 residue peptide that is the major component of amyloid deposits in familial British dementia. In the amyloid deposits, the ABri peptide adopts aggregated beta-pleated sheet structures, similar to those formed by the Abeta peptide of Alzheimer's disease and other amyloid forming proteins. As a first step toward elucidating the molecular mechanisms of the beta-amyloidosis, we explored the ability of the environmental variables (pH and peptide concentration) to promote beta-sheet fibril structures for synthetic ABri peptides. The secondary structures and fibril morphology were characterized in parallel using circular dichroism, atomic force microscopy, negative stain electron microscopy, Congo red, and thioflavin-T fluorescence spectroscopic techniques. As seen with other amyloid proteins, the ABri fibrils had characteristic binding with Congo red and thioflavin-T, and the relative amounts of beta-sheet and amyloid fibril-like structures are influenced strongly by pH. In the acidic pH range 3.1-4.3, the ABri peptide adopts almost exclusively random structure and a predominantly monomeric aggregation state, on the basis of analytical ultracentrifugation measurements. At neutral pH, 7.1-7.3, the ABri peptide had limited solubility and produced spherical and amorphous aggregates with predominantly beta-sheet secondary structure, whereas at slightly acidic pH, 4.9, spherical aggregates, intermediate-sized protofibrils, and larger-sized mature amyloid fibrils were detected by atomic force microscopy. With aging at pH 4.9, the protofibrils underwent further association and eventually formed mature fibrils. The presence of small amounts of aggregated peptide material or seeds encourage fibril formation at neutral pH, suggesting that generation of such seeds in vivo could promote amyloid formation. At slightly basic pH, 9.0, scrambling of the Cys5-Cys22 disulfide bond occurred, which could lead to the formation of covalently linked aggregates. The presence of the protofibrils and the enhanced aggregation at slightly acidic pH is consistent with the behavior of other amyloid-forming proteins, which supports the premise that a common mechanism may be involved in protein misfolding and beta-amyloidosis.
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Affiliation(s)
- Rekha Srinivasan
- Department of Chemistry, Case Western Reserve University, 2074 Adelbert Road, Millis Science Center, Cleveland, OH 44106-7078, USA
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Caughey B, Lansbury PT. Protofibrils, pores, fibrils, and neurodegeneration: separating the responsible protein aggregates from the innocent bystanders. Annu Rev Neurosci 2003; 26:267-98. [PMID: 12704221 DOI: 10.1146/annurev.neuro.26.010302.081142] [Citation(s) in RCA: 1263] [Impact Index Per Article: 60.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many neurodegenerative diseases, including Alzheimer's and Parkinson's and the transmissible spongiform encephalopathies (prion diseases), are characterized at autopsy by neuronal loss and protein aggregates that are typically fibrillar. A convergence of evidence strongly suggests that protein aggregation is neurotoxic and not a product of cell death. However, the identity of the neurotoxic aggregate and the mechanism by which it disables and eventually kills a neuron are unknown. Both biophysical studies aimed at elucidating the precise mechanism of in vitro aggregation and animal modeling studies support the emerging notion that an ordered prefibrillar oligomer, or protofibril, may be responsible for cell death and that the fibrillar form that is typically observed at autopsy may actually be neuroprotective. A subpopulation of protofibrils may function as pathogenic amyloid pores. An analogous mechanism may explain the neurotoxicity of the prion protein; recent data demonstrates that the disease-associated, infectious form of the prion protein differs from the neurotoxic species. This review focuses on recent experimental studies aimed at identification and characterization of the neurotoxic protein aggregates.
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Affiliation(s)
- Byron Caughey
- NIAID, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana, USA.
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Jiang Y, Li H, Zhu L, Zhou JM, Perrett S. Amyloid nucleation and hierarchical assembly of Ure2p fibrils. Role of asparagine/glutamine repeat and nonrepeat regions of the prion domains. J Biol Chem 2003; 279:3361-9. [PMID: 14610069 DOI: 10.1074/jbc.m310494200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The yeast prion protein Ure2 forms amyloid-like filaments in vivo and in vitro. This ability depends on the N-terminal prion domain, which contains Asn/Gln repeats, a motif thought to cause human disease by forming stable protein aggregates. The Asn/Gln region of the Ure2p prion domain extends to residue 89, but residues 15-42 represent an island of "normal" random sequence, which is highly conserved in related species and is relatively hydrophobic. We compare the time course of structural changes monitored by thioflavin T (ThT) binding fluorescence and atomic force microscopy for Ure2 and a series of prion domain mutants under a range of conditions. Atomic force microscopy height images at successive time points during a single growth experiment showed the sequential appearance of at least four fibril types that could be readily differentiated by height (5, 8, 12, or 9 nm), morphology (twisted or smooth), and/or time of appearance (early or late in the plateau phase of ThT binding). The Ure2 dimer (h = 2.6 +/- 0.5 nm) and granular particles corresponding to higher order oligomers (h = 4-12 nm) could also be detected. The mutants 15Ure2 and Delta 15-42Ure2 showed the same time-dependent variation in fibril types but with an increased lag time detected by ThT binding compared with wild-type Ure2. In addition, Delta 15-42Ure2 showed reduced binding to ThT. The results imply a role of the conserved region in both amyloid nucleation and formation of the binding surface recognized by ThT. Further, Ure2 amyloid formation is a multistep process via a series of fibrillar intermediates.
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Affiliation(s)
- Yi Jiang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China
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