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Wirths O, Lehnen C, Fricke M, Talucci I, Klafki HW, Morgado B, Lehmann S, Münch C, Liepold T, Wiltfang J, Rostagno A, Ghiso J, Maric HM, Jahn O, Weggen S. Amino-terminally elongated Aβ peptides are generated by the secreted metalloprotease ADAMTS4 and deposit in a subset of Alzheimer's disease brains. Neuropathol Appl Neurobiol 2024; 50:e12991. [PMID: 38867123 DOI: 10.1111/nan.12991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/06/2024] [Accepted: 05/09/2024] [Indexed: 06/14/2024]
Abstract
AIMS The aggregation and deposition of amyloid-β (Aβ) peptides in the brain is thought to be the initial driver in the pathogenesis of Alzheimer's disease (AD). Aside from full-length Aβ peptides starting with an aspartate residue in position 1, both N-terminally truncated and elongated Aβ peptides are produced by various proteases from the amyloid precursor protein (APP) and have been detected in brain tissues and body fluids. Recently, we demonstrated that the particularly abundant N-terminally truncated Aβ4-x peptides are generated by ADAMTS4, a secreted metalloprotease that is exclusively expressed in the oligodendrocyte cell population. In this study, we investigated whether ADAMTS4 might also be involved in the generation of N-terminally elongated Aβ peptides. METHODS We used cell-free and cell-based assays in combination with matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF) and electrochemiluminescence sandwich immunoassays to identify and quantify N-terminally elongated Aβ peptide variants. Antibodies against these Aβ variants were characterised by peptide microarrays and employed for the immunohistochemical analyses of human brain samples. RESULTS In this study, we discovered additional ADAMTS4 cleavage sites in APP. These were located N-terminal to Asp-(1) in the Aβ peptide sequence between residues Glu-(-7) and Ile-(-6) as well as Glu-(-4) and Val-(-3), resulting in the release of N-terminally elongated Aβ-6-x and Aβ-3-x peptides, of which the latter serve as a component in a promising Aβ-based plasma biomarker. Aβ-6/-3-40 peptides were detected in supernatants of various cell lines and in the cerebrospinal fluid (CSF), and ADAMTS4 enzyme activity promoted the release of Aβ-6/-3-x peptides. Furthermore, by immunohistochemistry, a subset of AD cases displayed evidence of extracellular and vascular localization of N-terminally elongated Aβ-6/-3-x peptides. DISCUSSION The current findings implicate ADAMTS4 in both the pathological process of Aβ peptide aggregation and in the early detection of amyloid pathology in AD.
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Affiliation(s)
- Oliver Wirths
- Department of Psychiatry and Psychotherapy, University Medical Center Goettingen (UMG), Georg-August University, Goettingen, Germany
| | - Christina Lehnen
- Department of Psychiatry and Psychotherapy, University Medical Center Goettingen (UMG), Georg-August University, Goettingen, Germany
| | - Merle Fricke
- Department of Psychiatry and Psychotherapy, University Medical Center Goettingen (UMG), Georg-August University, Goettingen, Germany
| | - Ivan Talucci
- Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Wuerzburg, Wuerzburg, Germany
- Department of Neurology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Hans-Wolfgang Klafki
- Department of Psychiatry and Psychotherapy, University Medical Center Goettingen (UMG), Georg-August University, Goettingen, Germany
| | - Barbara Morgado
- Department of Psychiatry and Psychotherapy, University Medical Center Goettingen (UMG), Georg-August University, Goettingen, Germany
| | - Sandra Lehmann
- Department of Neuropathology, Heinrich-Heine University, Duesseldorf, Germany
| | - Carolina Münch
- Department of Neuropathology, Heinrich-Heine University, Duesseldorf, Germany
| | - Thomas Liepold
- Department of Neurology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Jens Wiltfang
- Department of Psychiatry and Psychotherapy, University Medical Center Goettingen (UMG), Georg-August University, Goettingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Goettingen, Germany
- Neurosciences and Signaling Group, Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Agueda Rostagno
- Department of Pathology, New York University Grossman School of Medicine, New York, New York, USA
| | - Jorge Ghiso
- Department of Pathology, New York University Grossman School of Medicine, New York, New York, USA
| | - Hans Michael Maric
- Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Wuerzburg, Wuerzburg, Germany
| | - Olaf Jahn
- Department of Psychiatry and Psychotherapy, University Medical Center Goettingen (UMG), Georg-August University, Goettingen, Germany
- Neuroproteomics Group, Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Science (City Campus), Goettingen, Germany
| | - Sascha Weggen
- Department of Neuropathology, Heinrich-Heine University, Duesseldorf, Germany
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Ekanayake RSK, Streltsov VA, Best SP, Chantler CT. Nanostructure and dynamics of N-truncated copper amyloid-β peptides from advanced X-ray absorption fine structure. IUCRJ 2024; 11:325-346. [PMID: 38602752 PMCID: PMC11067746 DOI: 10.1107/s2052252524001830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 02/26/2024] [Indexed: 04/12/2024]
Abstract
An X-ray absorption spectroscopy (XAS) electrochemical cell was used to collect high-quality XAS measurements of N-truncated Cu:amyloid-β (Cu:Aβ) samples under near-physiological conditions. N-truncated Cu:Aβ peptide complexes contribute to oxidative stress and neurotoxicity in Alzheimer's patients' brains. However, the redox properties of copper in different Aβ peptide sequences are inconsistent. Therefore, the geometry of binding sites for the copper binding in Aβ4-8/12/16 was determined using novel advanced extended X-ray absorption fine structure (EXAFS) analysis. This enables these peptides to perform redox cycles in a manner that might produce toxicity in human brains. Fluorescence XAS measurements were corrected for systematic errors including defective-pixel data, monochromator glitches and dispersion of pixel spectra. Experimental uncertainties at each data point were measured explicitly from the point-wise variance of corrected pixel measurements. The copper-binding environments of Aβ4-8/12/16 were precisely determined by fitting XAS measurements with propagated experimental uncertainties, advanced analysis and hypothesis testing, providing a mechanism to pursue many similarly complex questions in bioscience. The low-temperature XAS measurements here determine that CuII is bound to the first amino acids in the high-affinity amino-terminal copper and nickel (ATCUN) binding motif with an oxygen in a tetragonal pyramid geometry in the Aβ4-8/12/16 peptides. Room-temperature XAS electrochemical-cell measurements observe metal reduction in the Aβ4-16 peptide. Robust investigations of XAS provide structural details of CuII binding with a very different bis-His motif and a water oxygen in a quasi-tetrahedral geometry. Oxidized XAS measurements of Aβ4-12/16 imply that both CuII and CuIII are accommodated in an ATCUN-like binding site. Hypotheses for these CuI, CuII and CuIII geometries were proven and disproven using the novel data and statistical analysis including F tests. Structural parameters were determined with an accuracy some tenfold better than literature claims of past work. A new protocol was also developed using EXAFS data analysis for monitoring radiation damage. This gives a template for advanced analysis of complex biosystems.
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Affiliation(s)
| | - Victor A. Streltsov
- School of Physics, University of Melbourne, Australia
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Australia
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Scheidt HA, Korn A, Schwarze B, Krueger M, Huster D. Conformation of Pyroglutamated Amyloid β (3-40) and (11-40) Fibrils - Extended or Hairpin? J Phys Chem B 2024; 128:1647-1655. [PMID: 38334278 PMCID: PMC10895672 DOI: 10.1021/acs.jpcb.3c07285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/04/2024] [Accepted: 01/30/2024] [Indexed: 02/10/2024]
Abstract
Amyloid β (Aβ) is a hallmark protein of Alzheimer's disease. One physiologically important Aβ variant is formed by initial N-terminal truncation at a glutamic acid position (either E3 or E11), which is subsequently cyclized to a pyroglutamate (either pE3 or pE11). Both forms have been found in high concentrations in the core of amyloid plaques and are likely of high importance in the pathology of Alzheimer's disease. However, the molecular structure of the fibrils of these variants is not entirely clear. Solid-state NMR spectroscopy studies have reported a molecular contact between Gly25 and Ile31, which would disagree with the conventional hairpin model of wildtype (WT-)Aβ1-40 fibrils, most often described in the literature. We investigated the conformation of the monomeric unit of pE3-Aβ3-40 and pE11-Aβ11-40 (and for comparison also wildtype (WT)-Aβ1-40) fibrils to find out whether the hairpin or a newly suggested extended structure dominates the structure of the Aβ monomers in these fibrils. To this end, solid-state NMR spectroscopy was applied probing the inter-residual contacts between Phe19/Leu34, Ala21/Leu34, and especially Gly25/Ile31 using suitable isotopic labeling schemes. In the second part, the flexible turn of the Aβ40 peptides was replaced by a (3-(3-aminomethyl)phenylazo)phenylacetic acid (AMPP)-based photoswitch, which can predefine the peptide conformation to either an extended (trans) or hairpin (cis) conformation. This enables simultaneous spectroscopic assessment of the conformation of the AMPP-photoswitch, allowing in situ structural investigations during fibrillation in contrast to structural techniques such as NMR spectroscopy or cryo-EM, which can only be applied to stable conformers. Both methods confirm an extended structure for the peptidic monomers in fibrils of all investigated Aβ variants. Especially the Gly25/Ile31 contact is a decisive indicator for the extended structure along with the characteristic absorption spectra of trans-AMPP-Aβ.
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Affiliation(s)
- Holger A. Scheidt
- Institute
for Medical Physics and Biophysics, Leipzig
University Härtelstr. 16/18, D-04107 Leipzig, Germany
| | - Alexander Korn
- Institute
for Medical Physics and Biophysics, Leipzig
University Härtelstr. 16/18, D-04107 Leipzig, Germany
| | - Benedikt Schwarze
- Institute
for Medical Physics and Biophysics, Leipzig
University Härtelstr. 16/18, D-04107 Leipzig, Germany
| | - Martin Krueger
- Institute
of Anatomy, Leipzig University, Liebigstr. 13, 04103 Leipzig, Germany
| | - Daniel Huster
- Institute
for Medical Physics and Biophysics, Leipzig
University Härtelstr. 16/18, D-04107 Leipzig, Germany
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van den Berg E, Kersten I, Brinkmalm G, Johansson K, de Kort AM, Klijn CJM, Schreuder FHBM, Gobom J, Stoops E, Portelius E, Gkanatsiou E, Zetterberg H, Blennow K, Kuiperij HB, Verbeek MM. Profiling amyloid-β peptides as biomarkers for cerebral amyloid angiopathy. J Neurochem 2024. [PMID: 38362804 DOI: 10.1111/jnc.16074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/08/2024] [Accepted: 01/24/2024] [Indexed: 02/17/2024]
Abstract
Brain amyloid-β (Aβ) deposits are key pathological hallmarks of both cerebral amyloid angiopathy (CAA) and Alzheimer's disease (AD). Microvascular deposits in CAA mainly consist of the Aβ40 peptide, whereas Aβ42 is the predominant variant in parenchymal plaques in AD. The relevance in pathogenesis and diagnostic accuracy of various other Aβ isoforms in CAA remain understudied. We aimed to investigate the biomarker potential of various Aβ isoforms in cerebrospinal fluid (CSF) to differentiate CAA from AD pathology. We included 25 patients with probable CAA, 50 subjects with a CSF profile indicative of AD pathology (AD-like), and 23 age- and sex-matched controls. CSF levels of Aβ1-34 , Aβ1-37 , Aβ1-38 , Aβ1-39 , Aβ1-40 , and Aβ1-42 were quantified by liquid chromatography mass spectrometry. Lower CSF levels of all six Aβ peptides were observed in CAA patients compared with controls (p = 0.0005-0.03). Except for Aβ1-42 (p = 1.0), all peptides were decreased in CAA compared with AD-like subjects (p = 0.007-0.03). Besides Aβ1-42 , none of the Aβ peptides were decreased in AD-like subjects compared with controls. All Aβ peptides combined differentiated CAA from AD-like subjects better (area under the curve [AUC] 0.84) than individual peptide levels (AUC 0.51-0.75). Without Aβ1-42 in the model (since decreased Aβ1-42 served as AD-like selection criterion), the AUC was 0.78 for distinguishing CAA from AD-like subjects. CAA patients and AD-like subjects showed distinct disease-specific CSF Aβ profiles. Peptides shorter than Aβ1-42 were decreased in CAA patients, but not AD-like subjects, which could suggest different pathological mechanisms between vascular and parenchymal Aβ accumulation. This study supports the potential use of this panel of CSF Aβ peptides to indicate presence of CAA pathology with high accuracy.
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Affiliation(s)
- Emma van den Berg
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Iris Kersten
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Gunnar Brinkmalm
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Kjell Johansson
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Anna M de Kort
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Catharina J M Klijn
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Floris H B M Schreuder
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Johan Gobom
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | | | - Erik Portelius
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Eleni Gkanatsiou
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Henrik Zetterberg
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- UK Dementia Research Institute at UCL, London, UK
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK
- Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China
- Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kaj Blennow
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - H Bea Kuiperij
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marcel M Verbeek
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
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5
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Klafki HW, Wirths O, Jahn O, Morgado B, Esselmann H, Wiltfang J. Blood plasma biomarkers for Alzheimer's disease: Aβ1-42/1-40 vs. AβX-42/X-40. Clin Chem Lab Med 2024; 62:e56-e57. [PMID: 37775501 DOI: 10.1515/cclm-2023-0990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 09/21/2023] [Indexed: 10/01/2023]
Affiliation(s)
- Hans-Wolfgang Klafki
- Department of Psychiatry and Psychotherapy, University Medical Center, Goettingen, Georg-August-University, Goettingen, Germany
| | - Oliver Wirths
- Department of Psychiatry and Psychotherapy, University Medical Center, Goettingen, Georg-August-University, Goettingen, Germany
| | - Olaf Jahn
- Department of Psychiatry and Psychotherapy, University Medical Center, Goettingen, Georg-August-University, Goettingen, Germany
| | - Barbara Morgado
- Department of Psychiatry and Psychotherapy, University Medical Center, Goettingen, Georg-August-University, Goettingen, Germany
| | - Hermann Esselmann
- Department of Psychiatry and Psychotherapy, University Medical Center, Goettingen, Georg-August-University, Goettingen, Germany
| | - Jens Wiltfang
- Department of Psychiatry and Psychotherapy, University Medical Center, Goettingen, Georg-August-University, Goettingen, Germany
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Kandi S, Cline EN, Rivera BM, Viola KL, Zhu J, Condello C, LeDuc RD, Klein WL, Kelleher NL, Patrie SM. Amyloid β Proteoforms Elucidated by Quantitative LC/MS in the 5xFAD Mouse Model of Alzheimer's Disease. J Proteome Res 2023; 22:3475-3488. [PMID: 37847596 PMCID: PMC10840081 DOI: 10.1021/acs.jproteome.3c00353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
Numerous Aβ proteoforms, identified in the human brain, possess differential neurotoxic and aggregation propensities. These proteoforms contribute in unknown ways to the conformations and resultant pathogenicity of oligomers, protofibrils, and fibrils in Alzheimer's disease (AD) manifestation owing to the lack of molecular-level specificity to the exact chemical composition of underlying protein products with widespread interrogating techniques, like immunoassays. We evaluated Aβ proteoform flux using quantitative top-down mass spectrometry (TDMS) in a well-studied 5xFAD mouse model of age-dependent Aβ-amyloidosis. Though the brain-derived Aβ proteoform landscape is largely occupied by Aβ1-42, 25 different forms of Aβ with differential solubility were identified. These proteoforms fall into three natural groups defined by hierarchical clustering of expression levels in the context of mouse age and proteoform solubility, with each group sharing physiochemical properties associated with either N/C-terminal truncations or both. Overall, the TDMS workflow outlined may hold tremendous potential for investigating proteoform-level relationships between insoluble fibrils and soluble Aβ, including low-molecular-weight oligomers hypothesized to serve as the key drivers of neurotoxicity. Similarly, the workflow may also help to validate the utility of AD-relevant animal models to recapitulate amyloidosis mechanisms or possibly explain disconnects observed in therapeutic efficacy in animal models vs humans.
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Affiliation(s)
- Soumya Kandi
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Erika N Cline
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Department of Neurobiology, Northwestern University, Evanston, Illinois 60208, United States
| | - Brianna M Rivera
- Institute for Neurodegenerative Diseases, UCSF Weill Institute for Neurosciences, University of California, San Francisco, California 94158, United States
| | - Kirsten L Viola
- Department of Neurobiology, Northwestern University, Evanston, Illinois 60208, United States
| | - Jiuhe Zhu
- Department of Neurobiology, Northwestern University, Evanston, Illinois 60208, United States
| | - Carlo Condello
- Institute for Neurodegenerative Diseases, UCSF Weill Institute for Neurosciences, University of California, San Francisco, California 94158, United States
- Department of Neurology, UCSF Weill Institute for Neurosciences, University of California, San Francisco, California 94158, United States
| | - Richard D LeDuc
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - William L Klein
- Department of Neurobiology, Northwestern University, Evanston, Illinois 60208, United States
| | - Neil L Kelleher
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Steven M Patrie
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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Canepa E, Parodi-Rullan R, Vazquez-Torres R, Gamallo-Lana B, Guzman-Hernandez R, Lemon NL, Angiulli F, Debure L, Ilies MA, Østergaard L, Wisniewski T, Gutiérrez-Jiménez E, Mar AC, Fossati S. FDA-approved carbonic anhydrase inhibitors reduce amyloid β pathology and improve cognition, by ameliorating cerebrovascular health and glial fitness. Alzheimers Dement 2023; 19:5048-5073. [PMID: 37186121 PMCID: PMC10600328 DOI: 10.1002/alz.13063] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/09/2023] [Accepted: 03/09/2023] [Indexed: 05/17/2023]
Abstract
INTRODUCTION Cerebrovascular pathology is an early and causal hallmark of Alzheimer's disease (AD), in need of effective therapies. METHODS Based on the success of our previous in vitro studies, we tested for the first time in a model of AD and cerebral amyloid angiopathy (CAA), the carbonic anhydrase inhibitors (CAIs) methazolamide and acetazolamide, Food and Drug Administration-approved against glaucoma and high-altitude sickness. RESULTS Both CAIs reduced cerebral, vascular, and glial amyloid beta (Aβ) accumulation and caspase activation, diminished gliosis, and ameliorated cognition in TgSwDI mice. The CAIs also improved microvascular fitness and induced protective glial pro-clearance pathways, resulting in the reduction of Aβ deposition. Notably, we unveiled that the mitochondrial carbonic anhydrase-VB (CA-VB) is upregulated in TgSwDI brains, CAA and AD+CAA human subjects, and in endothelial cells upon Aβ treatment. Strikingly, CA-VB silencing specifically reduces Aβ-mediated endothelial apoptosis. DISCUSSION This work substantiates the potential application of CAIs in clinical trials for AD and CAA.
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Affiliation(s)
- Elisa Canepa
- Alzheimer’s Center at Temple, Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Rebecca Parodi-Rullan
- Alzheimer’s Center at Temple, Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Rafael Vazquez-Torres
- Alzheimer’s Center at Temple, Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Begona Gamallo-Lana
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Roberto Guzman-Hernandez
- Alzheimer’s Center at Temple, Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Nicole L. Lemon
- Alzheimer’s Center at Temple, Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Federica Angiulli
- Alzheimer’s Center at Temple, Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Ludovic Debure
- Department on Neurology, Center for Cognitive Neurology, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Marc A. Ilies
- Department of Pharmaceutical Sciences and Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Temple University, Philadelphia, PA, 19140, USA
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, 8200 Aarhus, Denmark
| | - Thomas Wisniewski
- Department on Neurology, Center for Cognitive Neurology, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Eugenio Gutiérrez-Jiménez
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, 8200 Aarhus, Denmark
| | - Adam C. Mar
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Silvia Fossati
- Alzheimer’s Center at Temple, Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
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Singh R, Hussain J, Kaur A, Jamdare BG, Pathak D, Garg K, Kaur R, Shankar S, Sunkaria A. The hidden players: Shedding light on the significance of post-translational modifications and miRNAs in Alzheimer's disease development. Ageing Res Rev 2023; 90:102002. [PMID: 37423542 DOI: 10.1016/j.arr.2023.102002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/29/2023] [Accepted: 07/03/2023] [Indexed: 07/11/2023]
Abstract
Alzheimer's disease (AD) is the most prevalent, expensive, lethal, and burdening neurodegenerative disease of this century. The initial stages of this disease are characterized by a reduced ability to encode and store new memories. Subsequent cognitive and behavioral deterioration occurs during the later stages. Abnormal cleavage of amyloid precursor protein (APP) resulting in amyloid-beta (Aβ) accumulation along with hyperphosphorylation of tau protein are the two characteristic hallmarks of AD. Recently, several post-translational modifications (PTMs) have been identified on both Aβ as well as tau proteins. However, a complete understanding of how different PTMs influence the structure and function of proteins in both healthy and diseased conditions is still lacking. It has been speculated that these PTMs might play vital roles in the progression of AD. In addition, several short non-coding microRNA (miRNA) sequences have been found to be deregulated in the peripheral blood of Alzheimer patients. The miRNAs are single-stranded RNAs that control gene expression by causing mRNA degradation, deadenylation, or translational repression and have been implicated in the regulation of several neuronal and glial activities. The lack of comprehensive understanding regarding disease mechanisms, biomarkers, and therapeutic targets greatly hampers the development of effective strategies for early diagnosis and the identification of viable therapeutic targets. Moreover, existing treatment options for managing the disease have proven to be ineffective and provide only temporary relief. Therefore, understanding the role of miRNAs and PTMs in AD can provide valuable insights into disease mechanisms, aid in the identification of biomarkers, facilitate the discovery of novel therapeutic targets, and inspire innovative treatments for this challenging condition.
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Affiliation(s)
- Ravinder Singh
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, Punjab, India
| | - Julfequar Hussain
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, Punjab, India
| | - Amandeep Kaur
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, Punjab, India
| | - Balaji Gokul Jamdare
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, Punjab, India
| | - Deepti Pathak
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, Punjab, India
| | - Kanchan Garg
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, Punjab, India
| | - Ramanpreet Kaur
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, Punjab, India
| | - Shivani Shankar
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, Punjab, India
| | - Aditya Sunkaria
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, Punjab, India.
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Ikegawa M, Kakuda N, Miyasaka T, Toyama Y, Nirasawa T, Minta K, Hanrieder J. Mass Spectrometry Imaging in Alzheimer's Disease. Brain Connect 2023; 13:319-333. [PMID: 36905365 PMCID: PMC10494909 DOI: 10.1089/brain.2022.0057] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023] Open
Abstract
Introduction: Amyloid-beta (Aβ) pathology is the precipitating histopathological characteristic of Alzheimer's disease (AD). Although the formation of amyloid plaques in human brains is suggested to be a key factor in initiating AD pathogenesis, it is still not fully understood the upstream events that lead to Aβ plaque formation and its metabolism inside the brains. Methods: Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) has been successfully introduced to study AD pathology in brain tissue both in AD mouse models and human samples. By using MALDI-MSI, a highly selective deposition of Aβ peptides in AD brains with a variety of cerebral amyloid angiopathy (CAA) involvement was observed. Results: MALDI-MSI visualized depositions of shorter peptides in AD brains; Aβ1-36 to Aβ1-39 were quite similarly distributed with Aβ1-40 as a vascular pattern, and deposition of Aβ1-42 and Aβ1-43 was visualized with a distinct senile plaque pattern distributed in parenchyma. Moreover, how MALDI-MSI covered in situ lipidomics of plaque pathology has been reviewed, which is of interest as aberrations in neuronal lipid biochemistry have been implicated in AD pathogenesis. Discussion: In this study, we introduce the methodological concepts and challenges of MALDI-MSI for the studies of AD pathogenesis. Diverse Aβ isoforms including various C- and N-terminal truncations in AD and CAA brain tissues will be visualized. Despite the close relationship between vascular and plaque Aβ deposition, the current strategy will define cross talk between neurodegenerative and cerebrovascular processes at the level of Aβ metabolism.
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Affiliation(s)
- Masaya Ikegawa
- Department of Life and Medical Systems, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Nobuto Kakuda
- Department of Life and Medical Systems, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Tomohiro Miyasaka
- Department of Life and Medical Systems, Doshisha University, Kyotanabe, Kyoto, Japan
| | - Yumiko Toyama
- Department of Life and Medical Systems, Doshisha University, Kyotanabe, Kyoto, Japan
| | | | - Karolina Minta
- Department of Psychiatry and Neurochemistry, Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Department of Neurodegenerative Disease, Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Jörg Hanrieder
- Department of Psychiatry and Neurochemistry, Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Department of Neurodegenerative Disease, Queen Square Institute of Neurology, University College London, London, United Kingdom
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10
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Bader AS, Gnädig MU, Fricke M, Büschgens L, Berger LJ, Klafki HW, Meyer T, Jahn O, Weggen S, Wirths O. Brain Region-Specific Differences in Amyloid-β Plaque Composition in 5XFAD Mice. Life (Basel) 2023; 13:life13041053. [PMID: 37109582 PMCID: PMC10145597 DOI: 10.3390/life13041053] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/11/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023] Open
Abstract
Senile plaques consisting of amyloid-beta (Aβ) peptides are a major pathological hallmark of Alzheimer's disease (AD). Aβ peptides are heterogeneous regarding the exact length of their amino- and carboxy-termini. Aβ1-40 and Aβ1-42 are often considered to represent canonical "full-length" Aβ species. Using immunohistochemistry, we analyzed the distribution of Aβ1-x, Aβx-42 and Aβ4-x species in amyloid deposits in the subiculum, hippocampus and cortex in 5XFAD mice during aging. Overall plaque load increased in all three brain regions, with the subiculum being the area with the strongest relative plaque coverage. In the subiculum, but not in the other brain regions, the Aβ1-x load peaked at an age of five months and decreased thereafter. In contrast, the density of plaques positive for N-terminally truncated Aβ4-x species increased continuously over time. We hypothesize that ongoing plaque remodeling takes place, leading to a conversion of deposited Aβ1-x peptides into Aβ4-x peptides in brain regions with a high Aβ plaque burden.
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Affiliation(s)
- Angelika Sabine Bader
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, 37075 Göttingen, Germany
| | - Marius-Uwe Gnädig
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, 37075 Göttingen, Germany
| | - Merle Fricke
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, 37075 Göttingen, Germany
| | - Luca Büschgens
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, 37075 Göttingen, Germany
| | - Lena Josefine Berger
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, 37075 Göttingen, Germany
| | - Hans-Wolfgang Klafki
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, 37075 Göttingen, Germany
| | - Thomas Meyer
- Department of Psychosomatic Medicine and Psychotherapy, University Medical Center (UMG), Georg-August-University, 37075 Göttingen, Germany
| | - Olaf Jahn
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, 37075 Göttingen, Germany
- Neuroproteomics Group, Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, 37075 Göttingen, Germany
| | - Sascha Weggen
- Department of Neuropathology, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Oliver Wirths
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, 37075 Göttingen, Germany
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11
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Liepold T, Klafki HW, Kumar S, Walter J, Wirths O, Wiltfang J, Jahn O. Matrix Development for the Detection of Phosphorylated Amyloid-β Peptides by MALDI-TOF-MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:505-512. [PMID: 36706152 PMCID: PMC9983008 DOI: 10.1021/jasms.2c00270] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/20/2022] [Accepted: 01/18/2023] [Indexed: 06/18/2023]
Abstract
Amyloid-β (Aβ) peptides, including post-translationally modified variants thereof, are believed to play a key role in the onset and progression of Alzheimer's disease. Suggested modified Aβ species with potential disease relevance include Aβ peptides phosphorylated at serine in position eight (pSer8-Aβ) or 26 (pSer26-Aβ). However, the published studies on those Aβ peptides essentially relied on antibody-based approaches. Thus, complementary analyses by mass spectrometry, as shown for other modified Aβ variants, will be necessary not only to unambiguously verify the existence of phosphorylated Aβ species in brain samples but also to reveal their exact identity as to phosphorylation sites and potential terminal truncations. With the aim of providing a novel tool for addressing this still-unresolved issue, we developed a customized matrix formulation, referred to as TOPAC, that allows for improved detection of synthetic phosphorylated Aβ species by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. When TOPAC was compared with standard matrices, we observed higher signal intensities but minimal methionine oxidation and phosphate loss for intact pSer8-Aβ(1-40) and pSer26-Aβ(1-40). Similarly, TOPAC also improved the mass spectrometric detection and sequencing of the proteolytic cleavage products pSer8-Aβ(1-16) and pSer26-Aβ(17-28). We expect that TOPAC will facilitate future efforts to detect and characterize endogenous phosphorylated Aβ species in biological samples and that it may also find its use in phospho-proteomic approaches apart from applications in the Aβ field.
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Affiliation(s)
- Thomas Liepold
- Neuroproteomics
Group, Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, 37075 Goettingen, Germany
| | - Hans-Wolfgang Klafki
- Department
of Psychiatry and Psychotherapy, University Medical Center Goettingen, Georg-August-University, 37075 Goettingen, Germany
| | - Sathish Kumar
- Department
of Neurology, University of Bonn, 53127 Bonn, Germany
| | - Jochen Walter
- Department
of Neurology, University of Bonn, 53127 Bonn, Germany
| | - Oliver Wirths
- Department
of Psychiatry and Psychotherapy, University Medical Center Goettingen, Georg-August-University, 37075 Goettingen, Germany
| | - Jens Wiltfang
- Department
of Psychiatry and Psychotherapy, University Medical Center Goettingen, Georg-August-University, 37075 Goettingen, Germany
| | - Olaf Jahn
- Neuroproteomics
Group, Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, 37075 Goettingen, Germany
- Department
of Psychiatry and Psychotherapy, University Medical Center Goettingen, Georg-August-University, 37075 Goettingen, Germany
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12
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Is plasma amyloid-β 1–42/1–40 a better biomarker for Alzheimer’s disease than AβX–42/X–40? Fluids Barriers CNS 2022; 19:96. [DOI: 10.1186/s12987-022-00390-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 10/20/2022] [Indexed: 12/04/2022] Open
Abstract
Abstract
Background
A reduced amyloid-β (Aβ)42/40 peptide ratio in blood plasma represents a peripheral biomarker of the cerebral amyloid pathology observed in Alzheimer’s disease brains. The magnitude of the measurable effect in plasma is smaller than in cerebrospinal fluid, presumably due to dilution by Aβ peptides originating from peripheral sources. We hypothesized that the observable effect in plasma can be accentuated to some extent by specifically measuring Aβ1–42 and Aβ1–40 instead of AβX–42 and AβX–40.
Methods
We assessed the plasma AβX–42/X–40 and Aβ1–42/1–40 ratios in an idealized clinical sample by semi-automated Aβ immunoprecipitation followed by closely related sandwich immunoassays. The amyloid-positive and amyloid-negative groups (dichotomized according to Aβ42/40 in cerebrospinal fluid) were compared regarding the median difference, mean difference, standardized effect size (Cohen’s d) and receiver operating characteristic curves. For statistical evaluation, we applied bootstrapping.
Results
The median Aβ1–42/1–40 ratio was 20.86% lower in amyloid-positive subjects than in the amyloid-negative group, while the median AβX–42/X–40 ratio was only 15.56% lower. The relative mean difference between amyloid-positive and amyloid-negative subjects was −18.34% for plasma Aβ1–42/1–40 compared to −15.50% for AβX–42/X–40. Cohen’s d was 1.73 for Aβ1–42/1–40 and 1.48 for plasma AβX–42/X–40. Unadjusted p-values < 0.05 were obtained after .632 bootstrapping for all three parameters. Receiver operating characteristic analysis indicated very similar areas under the curves for plasma Aβ1–42/1–40 and AβX–42/X–40.
Conclusions
Our findings support the hypothesis that the relatively small difference in the plasma Aβ42/40 ratio between subjects with and without evidence of brain amyloidosis can be accentuated by specifically measuring Aβ1–42/1–40 instead of AβX–42/X–40. A simplified theoretical model explaining this observation is presented.
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13
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An atlas of amyloid aggregation: the impact of substitutions, insertions, deletions and truncations on amyloid beta fibril nucleation. Nat Commun 2022; 13:7084. [PMID: 36400770 PMCID: PMC9674652 DOI: 10.1038/s41467-022-34742-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 11/04/2022] [Indexed: 11/19/2022] Open
Abstract
Multiplexed assays of variant effects (MAVEs) guide clinical variant interpretation and reveal disease mechanisms. To date, MAVEs have focussed on a single mutation type-amino acid (AA) substitutions-despite the diversity of coding variants that cause disease. Here we use Deep Indel Mutagenesis (DIM) to generate a comprehensive atlas of diverse variant effects for a disease protein, the amyloid beta (Aβ) peptide that aggregates in Alzheimer's disease (AD) and is mutated in familial AD (fAD). The atlas identifies known fAD mutations and reveals that many variants beyond substitutions accelerate Aβ aggregation and are likely to be pathogenic. Truncations, substitutions, insertions, single- and internal multi-AA deletions differ in their propensity to enhance or impair aggregation, but likely pathogenic variants from all classes are highly enriched in the polar N-terminal region of Aβ. This comparative atlas highlights the importance of including diverse mutation types in MAVEs and provides important mechanistic insights into amyloid nucleation.
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14
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Oumata N, Lu K, Teng Y, Cavé C, Peng Y, Galons H, Roques BP. Molecular mechanisms in Alzheimer's disease and related potential treatments such as structural target convergence of antibodies and simple organic molecules. Eur J Med Chem 2022; 240:114578. [PMID: 35841881 DOI: 10.1016/j.ejmech.2022.114578] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 06/25/2022] [Accepted: 06/26/2022] [Indexed: 12/12/2022]
Abstract
The amyloid cascade is the most frequently accepted hypothesis of Alzheimer's Disease (AD). According to this hypothesis, the formation of plaques precedes the appearance of fibrillary tangles. Therapeutic agents able to inhibit the formation of plaques are therefore considered as potential disease-modifying treatments (DMT) that could prevent or limit the progression of AD. Plaques are deposits formed by aggregates of amyloid-β (Aβ)-peptides. These peptides are metabolites of amyloid precursor protein (APP) first mediated by two enzymes: β-secretase 1 (BACE1) and γ-secretase. Molecular identification of these two enzymes has stimulated the development of their inhibitors. The clinical testing of these two classes of molecules has not been successful to date. The oligomerization of Aβ-peptides into plaques is now targeted by immunological approaches such as antibodies and vaccines. Structural consideration of the Aβ-peptide sequence led to the launch of the antibody Aducanumab. Several other antibodies are in late clinical phases. Progress in the understanding of the effects of N-truncated Aβ-peptides such as pE3-42, formed by the action of recently well characterized enzymes (aminopeptidase A, dipeptidylpeptidase-4 and glutaminyl cyclase) suggests that oligomerization can be limited either by enzyme inhibitors or antibody approaches. This strategy associating two structurally interconnected mechanisms is focused in this review.
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Affiliation(s)
- Nassima Oumata
- Unité de Technologies Chimiques et Biologiques pour la Santé, Université Paris Cité INSERM U1267, CNRS UMR 8258, 4 Avenue de l'Observatoire, Paris, 75006, France
| | - Kui Lu
- Tianjin International Cooperation Research Centre of Food Nutrition/Safety and Medicinal Chemistry, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Yuou Teng
- Tianjin International Cooperation Research Centre of Food Nutrition/Safety and Medicinal Chemistry, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Christian Cavé
- UMR CNRS 8076 BioCIS, Faculty of Pharmacy, University Paris-Saclay, France
| | - Yu Peng
- Tianjin International Cooperation Research Centre of Food Nutrition/Safety and Medicinal Chemistry, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Hervé Galons
- Unité de Technologies Chimiques et Biologiques pour la Santé, Université Paris Cité INSERM U1267, CNRS UMR 8258, 4 Avenue de l'Observatoire, Paris, 75006, France; Tianjin International Cooperation Research Centre of Food Nutrition/Safety and Medicinal Chemistry, Tianjin University of Science & Technology, Tianjin, 300457, China.
| | - Bernard P Roques
- Unité de Technologies Chimiques et Biologiques pour la Santé, Université Paris Cité INSERM U1267, CNRS UMR 8258, 4 Avenue de l'Observatoire, Paris, 75006, France.
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15
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N-terminally truncated Aβ4-x proteoforms and their relevance for Alzheimer's pathophysiology. Transl Neurodegener 2022; 11:30. [PMID: 35641972 PMCID: PMC9158284 DOI: 10.1186/s40035-022-00303-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 04/21/2022] [Indexed: 01/22/2023] Open
Abstract
Background The molecular heterogeneity of Alzheimer’s amyloid-β (Aβ) deposits extends well beyond the classic Aβ1-40/Aβ1-42 dichotomy, substantially expanded by multiple post-translational modifications that increase the proteome diversity. Numerous truncated fragments consistently populate the brain Aβ peptidome, and their homeostatic regulation and potential contribution to disease pathogenesis are largely unknown. Aβ4-x peptides have been reported as major components of plaque cores and the limited studies available indicate their relative abundance in Alzheimer’s disease (AD). Methods Immunohistochemistry was used to assess the topographic distribution of Aβ4-x species in well-characterized AD cases using custom-generated monoclonal antibody 18H6—specific for Aβ4-x species and blind for full-length Aβ1-40/Aβ1-42—in conjunction with thioflavin-S and antibodies recognizing Aβx-40 and Aβx-42 proteoforms. Circular dichroism, thioflavin-T binding, and electron microscopy evaluated the biophysical and aggregation/oligomerization properties of full-length and truncated synthetic homologues, whereas stereotaxic intracerebral injections of monomeric and oligomeric radiolabeled homologues in wild-type mice were used to evaluate their brain clearance characteristics. Results All types of amyloid deposits contained the probed Aβ epitopes, albeit expressed in different proportions. Aβ4-x species showed preferential localization within thioflavin-S-positive cerebral amyloid angiopathy and cored plaques, strongly suggesting poor clearance characteristics and consistent with the reduced solubility and enhanced oligomerization of their synthetic homologues. In vivo clearance studies demonstrated a fast brain efflux of N-terminally truncated and full-length monomeric forms whereas their oligomeric counterparts—particularly of Aβ4-40 and Aβ4-42—consistently exhibited enhanced brain retention. Conclusions The persistence of aggregation-prone Aβ4-x proteoforms likely contributes to the process of amyloid formation, self-perpetuating the amyloidogenic loop and exacerbating amyloid-mediated pathogenic pathways.
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16
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Abstract
Amyloid-β (Aβ) peptides are involved in Alzheimer's disease (AD) development. The interactions of these peptides with copper and zinc ions also seem to be crucial for this pathology. Although Cu(II) and Zn(II) ions binding by Aβ peptides has been scrupulously investigated, surprisingly, this phenomenon has not been so thoroughly elucidated for N-truncated Aβ4-x-probably the most common version of this biomolecule. This negligence also applies to mixed Cu-Zn complexes. From the structural in silico analysis presented in this work, it appears that there are two possible mixed Cu-Zn(Aβ4-x) complexes with different stoichiometries and, consequently, distinct properties. The Cu-Zn(Aβ4-x) complex with 1:1:1 stoichiometry may have a neuroprotective superoxide dismutase-like activity. On the other hand, another mixed 2:1:2 Cu-Zn(Aβ4-x) complex is perhaps a seed for toxic oligomers. Hence, this work proposes a novel research direction for our better understanding of AD development.
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17
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Parodi-Rullán RM, Javadov S, Fossati S. Dissecting the Crosstalk between Endothelial Mitochondrial Damage, Vascular Inflammation, and Neurodegeneration in Cerebral Amyloid Angiopathy and Alzheimer's Disease. Cells 2021; 10:cells10112903. [PMID: 34831125 PMCID: PMC8616424 DOI: 10.3390/cells10112903] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/22/2021] [Accepted: 10/24/2021] [Indexed: 12/25/2022] Open
Abstract
Alzheimer’s disease (AD) is the most prevalent cause of dementia and is pathologically characterized by the presence of parenchymal senile plaques composed of amyloid β (Aβ) and intraneuronal neurofibrillary tangles of hyperphosphorylated tau protein. The accumulation of Aβ also occurs within the cerebral vasculature in over 80% of AD patients and in non-demented individuals, a condition called cerebral amyloid angiopathy (CAA). The development of CAA is associated with neurovascular dysfunction, blood–brain barrier (BBB) leakage, and persistent vascular- and neuro-inflammation, eventually leading to neurodegeneration. Although pathologically AD and CAA are well characterized diseases, the chronology of molecular changes that lead to their development is still unclear. Substantial evidence demonstrates defects in mitochondrial function in various cells of the neurovascular unit as well as in the brain parenchyma during the early stages of AD and CAA. Dysfunctional mitochondria release danger-associated molecular patterns (DAMPs) that activate a wide range of inflammatory pathways. In this review, we gather evidence to postulate a crucial role of the mitochondria, specifically of cerebral endothelial cells, as sensors and initiators of Aβ-induced vascular inflammation. The activated vasculature recruits circulating immune cells into the brain parenchyma, leading to the development of neuroinflammation and neurodegeneration in AD and CAA.
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Affiliation(s)
- Rebecca M. Parodi-Rullán
- Alzheimer’s Center at Temple, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA;
| | - Sabzali Javadov
- Department of Physiology, University of Puerto Rico School of Medicine, San Juan, PR 00921, USA;
| | - Silvia Fossati
- Alzheimer’s Center at Temple, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA;
- Correspondence: ; Tel.: +1-215-707-6046
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18
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Bayer TA. N-Truncated Aβ Starting at Position Four-Biochemical Features, Preclinical Models, and Potential as Drug Target in Alzheimer's Disease. Front Aging Neurosci 2021; 13:710579. [PMID: 34489680 PMCID: PMC8417877 DOI: 10.3389/fnagi.2021.710579] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 07/29/2021] [Indexed: 12/21/2022] Open
Abstract
The discussion of whether amyloid plaque Aβ is a valid drug target to fight Alzheimer’s disease (AD) has been a matter of scientific dispute for decades. This question can only be settled by successful clinical trials and the approval of disease-modifying drugs. However, many clinical trials with antibodies against different regions of the amyloid Aβ peptide have been discontinued, as they did not meet the clinical endpoints required. Recently, passive immunization of AD patients with Donanemab, an antibody directed against the N-terminus of pyroglutamate Aβ, showed beneficial effects in a phase II trial, supporting the concept that N-truncated Aβ is a relevant target for AD therapy. There is long-standing evidence that N-truncated Aβ variants are the main variants found in amyloid plaques besides full-length Aβ1–42, t, therefore their role in triggering AD pathology and as targets for drug development are of interest. While the contribution of pyroglutamate Aβ3–42 to AD pathology has been well studied in the past, the potential role of Aβ4–42 has been largely neglected. The present review will therefore focus on Aβ4–42 as a possible drug target based on human and mouse pathology, in vitro and in vivo toxicity, and anti-Aβ4-X therapeutic effects in preclinical models.
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Affiliation(s)
- Thomas A Bayer
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center Göttingen (UMG), Georg-August-University, Göttingen, Germany
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19
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Abidi SMS, Dar AI, Acharya A. Multifunctional Gold Nanoparticle-Conjugated Cellulose Nanoonions Alleviate Aβ42 Fibrillation-Induced Toxicity via Regulation of Oxidative Stress and Ion Homeostasis. Biomacromolecules 2021; 22:2419-2435. [PMID: 33945268 DOI: 10.1021/acs.biomac.1c00228] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Inhibition of hen egg white lysozyme (HEWL) and Aβ42 fibrillation have been established as the main models for the treatment of systemic lysozyme amyloidosis and Alzheimer's disease (AD), respectively. Several antiamyloidogenic nanomaterials have been developed over the period; however, their intracellular mechanism of action is still not well understood. In this context, plant-based, gold-conjugated, injectable, hydrophilic cellulose nanoonions (CNOs), viz., DH-CNO (∼60 ± 5 nm) and LC-CNO (∼55 ± 12 nm), were developed from their respective hydrophobic cellulose nanocrystals (DH-CNC and LC-CNC) using a single-step chemical template-mediated process. This unique nanocellulose architecture was chemically and morphologically characterized by various spectroscopic and microscopic techniques. Further, the different biophysical studies documented marked the inhibition/disintegration potential of gold-conjugated LC-CNO against HEWL and Aβ42 peptide aggregation. It was further observed that inhibition of protein fibrillation could be achieved within ∼10 min when the same materials were used under photoirradiation conditions. In vitro protein aggregation studies using HEK293 cells suggested that gold-conjugated LC-CNO could effectively reduce the cellular toxicity via regulation of oxidative stress and ion homeostasis. The outcome of the present study will help in designing cellulose-based novel functional nanochaperones against various neurodegenerative diseases.
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Affiliation(s)
- Syed M S Abidi
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India.,Academy of Scientific & Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh201002, India
| | - Aqib Iqbal Dar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India.,Academy of Scientific & Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh201002, India
| | - Amitabha Acharya
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India.,Academy of Scientific & Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh201002, India
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20
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Mukherjee S, Perez KA, Lago LC, Klatt S, McLean CA, Birchall IE, Barnham KJ, Masters CL, Roberts BR. Quantification of N-terminal amyloid-β isoforms reveals isomers are the most abundant form of the amyloid-β peptide in sporadic Alzheimer's disease. Brain Commun 2021; 3:fcab028. [PMID: 33928245 PMCID: PMC8062259 DOI: 10.1093/braincomms/fcab028] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/09/2021] [Accepted: 01/15/2021] [Indexed: 12/30/2022] Open
Abstract
Plaques that characterize Alzheimer’s disease accumulate over 20 years as a result of decreased clearance of amyloid-β peptides. Such long-lived peptides are subjected to multiple post-translational modifications, in particular isomerization. Using liquid chromatography ion mobility separations mass spectrometry, we characterized the most common isomerized amyloid-β peptides present in the temporal cortex of sporadic Alzheimer’s disease brains. Quantitative assessment of amyloid-β N-terminus revealed that > 80% of aspartates (Asp-1 and Asp-7) in the N-terminus was isomerized, making isomerization the most dominant post-translational modification of amyloid-β in Alzheimer’s disease brain. Total amyloid-β1–15 was ∼85% isomerized at Asp-1 and/or Asp-7 residues, with only 15% unmodified amyloid-β1–15 left in Alzheimer’s disease. While amyloid-β4–15 the next most abundant N-terminus found in Alzheimer’s disease brain, was only ∼50% isomerized at Asp-7 in Alzheimer’s disease. Further investigations into different biochemically defined amyloid-β-pools indicated a distinct pattern of accumulation of extensively isomerized amyloid-β in the insoluble fibrillar plaque and membrane-associated pools, while the extent of isomerization was lower in peripheral membrane/vesicular and soluble pools. This pattern correlated with the accumulation of aggregation-prone amyloid-β42 in Alzheimer’s disease brains. Isomerization significantly alters the structure of the amyloid-β peptide, which not only has implications for its degradation, but also for oligomer assembly, and the binding of therapeutic antibodies that directly target the N-terminus, where these modifications are located.
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Affiliation(s)
- Soumya Mukherjee
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Keyla A Perez
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Larissa C Lago
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Stephan Klatt
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Catriona A McLean
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia.,Department of Anatomical Pathology, Alfred Hospital, Prahran, VIC 3004, Australia
| | - Ian E Birchall
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Kevin J Barnham
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Colin L Masters
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Blaine R Roberts
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia.,Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
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21
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The Aggregation Pattern of Aβ
1–40
is Altered by the Presence of
N
‐Truncated Aβ
4–40
and/or Cu
II
in a Similar Way through Ionic Interactions. Chemistry 2021; 27:2798-2809. [DOI: 10.1002/chem.202004484] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Indexed: 12/19/2022]
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22
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Scheidt HA, Das A, Korn A, Krueger M, Maiti S, Huster D. Structural characteristics of oligomers formed by pyroglutamate-modified amyloid β peptides studied by solid-state NMR. Phys Chem Chem Phys 2020; 22:16887-16895. [PMID: 32666970 DOI: 10.1039/d0cp02307h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Neuronal plaques of amyloid β (Aβ) peptides of varying length carrying different posttranslational modifications represent a molecular hallmark of Alzheimer's disease. It is believed that transient oligomeric Aβ assemblies associating in early fibrillation events represent particularly cytotoxic peptide aggregates. Also, N-terminally truncated (in position 3 or 11) and pyroglutamate modified peptides exhibited an increased toxicity compared to the wildtype. In the current study, the molecular structure of oligomeric species of pGlu3-Aβ(3-40) and pGlu11-Aβ(11-40) was investigated using solid-state NMR spectroscopy. On the secondary structure level, for both modified peptides a large similarity between oligomers and mature fibrils of the modified peptides was found mainly based on 13C NMR chemical shift data. Some smaller structural differences were detected in the vicinity of the respective modification site. Also, the crucial early folding molecular contact between residues Phe19 and Leu34 could be observed for the oligomers of both modified peptide species. Therefore, it has to be concluded that the major secondary structure elements of Aβ are already present in oligomers of pGlu3-Aβ(3-40) and pGlu11-Aβ(11-40). These posttranslationally modified peptides arrange in a similar fashion as observed for wild type Aβ(1-40).
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Affiliation(s)
- Holger A Scheidt
- Institute for Medical Physics and Biophysics, Leipzig University Härtelstr. 16-18, D-04107 Leipzig, Germany.
| | - Anirban Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
| | - Alexander Korn
- Institute for Medical Physics and Biophysics, Leipzig University Härtelstr. 16-18, D-04107 Leipzig, Germany.
| | - Martin Krueger
- Institute of Anatomy, Leipzig University, Liebigstraße 13, 04103 Leipzig, Germany
| | - Sudipta Maiti
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Leipzig University Härtelstr. 16-18, D-04107 Leipzig, Germany. and Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
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23
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Evaluation of on-line solid-phase extraction capillary electrophoresis-mass spectrometry with a nanoliter valve for the analysis of peptide biomarkers. Anal Chim Acta 2020; 1140:1-9. [PMID: 33218471 DOI: 10.1016/j.aca.2020.09.036] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/11/2020] [Accepted: 09/18/2020] [Indexed: 11/20/2022]
Abstract
On-line solid-phase extraction capillary electrophoresis-mass spectrometry (SPE-CE-MS) is a powerful technique for high throughput sample clean-up and analyte preconcentration, separation, detection, and characterization. The most typical design due to its simplicity and low cost is unidirectional SPE-CE-MS. However, in this configuration, the sample volumes introduced by pressure depend on the dimensions of the separation capillary and some matrix components could be irreversibly adsorbed in its inner walls. Furthermore, in many cases, the requirements of on-line preconcentration are incompatible with the background electrolyte necessary for an efficient separation and sensitive MS detection. Here, we present SPE-CE-MS with a nanoliter valve (nvSPE-CE-MS) to overcome these drawbacks while keeping the design simple. The nvSPE-CE-MS system is operated with a single CE instrument and two capillaries for independent and orthogonal SPE preconcentration and CE separation, which are interfaced through an external and electrically isolated valve with a 20 nL sample loop. The instrumental setup is proved for the analysis of opioid and amyloid beta peptide biomarkers in standards and plasma samples. NvSPE-CE-MS allowed decreasing the limits of detection (LODs) 200 times with regard to CE-MS. Compared to unidirectional SPE-CE-MS, peak efficiencies were better and repeatabilities similar, but total analysis times longer and LODs for standards slightly higher due to the heart-cut operation and the limited volume of the valve loop. This small difference on the LODs for standards was compensated for plasma samples by the improved tolerance of nvSPE-CE-MS to complex sample matrices. In view of these results, the presented setup can be regarded as a promising versatile alternative to avoid complicated matrix samples entering the separation capillary in SPE-CE-MS.
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24
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Mital M, Szutkowski K, Bossak-Ahmad K, Skrobecki P, Drew SC, Poznański J, Zhukov I, Frączyk T, Bal W. The Palladium(II) Complex of A β4-16 as Suitable Model for Structural Studies of Biorelevant Copper(II) Complexes of N-Truncated Beta-Amyloids. Int J Mol Sci 2020; 21:E9200. [PMID: 33276669 PMCID: PMC7731285 DOI: 10.3390/ijms21239200] [Citation(s) in RCA: 2] [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: 11/12/2020] [Revised: 11/26/2020] [Accepted: 11/30/2020] [Indexed: 11/16/2022] Open
Abstract
The Aβ4-42 peptide is a major beta-amyloid species in the human brain, forming toxic aggregates related to Alzheimer's Disease. It also strongly chelates Cu(II) at the N-terminal Phe-Arg-His ATCUN motif, as demonstrated in Aβ4-16 and Aβ4-9 model peptides. The resulting complex resists ROS generation and exchange processes and may help protect synapses from copper-related oxidative damage. Structural characterization of Cu(II)Aβ4-x complexes by NMR would help elucidate their biological function, but is precluded by Cu(II) paramagneticism. Instead we used an isostructural diamagnetic Pd(II)-Aβ4-16 complex as a model. To avoid a kinetic trapping of Pd(II) in an inappropriate transient structure, we designed an appropriate pH-dependent synthetic procedure for ATCUN Pd(II)Aβ4-16, controlled by CD, fluorescence and ESI-MS. Its assignments and structure at pH 6.5 were obtained by TOCSY, NOESY, ROESY, 1H-13C HSQC and 1H-15N HSQC NMR experiments, for natural abundance 13C and 15N isotopes, aided by corresponding experiments for Pd(II)-Phe-Arg-His. The square-planar Pd(II)-ATCUN coordination was confirmed, with the rest of the peptide mostly unstructured. The diffusion rates of Aβ4-16, Pd(II)-Aβ4-16 and their mixture determined using PGSE-NMR experiment suggested that the Pd(II) complex forms a supramolecular assembly with the apopeptide. These results confirm that Pd(II) substitution enables NMR studies of structural aspects of Cu(II)-Aβ complexes.
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Affiliation(s)
- Mariusz Mital
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Kosma Szutkowski
- NanoBioMedical Centre, Adam Mickiewicz University, 61-614 Poznań, Poland;
| | - Karolina Bossak-Ahmad
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Piotr Skrobecki
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Simon C. Drew
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Jarosław Poznański
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Igor Zhukov
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Tomasz Frączyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warszawa, Poland; (M.M.); (K.B.-A.); (P.S.); (S.C.D.); (J.P.)
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25
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Stefaniak E, Pushie MJ, Vaerewyck C, Corcelli D, Griggs C, Lewis W, Kelley E, Maloney N, Sendzik M, Bal W, Haas KL. Exploration of the Potential Role for Aβ in Delivery of Extracellular Copper to Ctr1. Inorg Chem 2020; 59:16952-16966. [PMID: 33211469 DOI: 10.1021/acs.inorgchem.0c02100] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyloid beta (Aβ) peptides are notorious for their involvement in Alzheimer's disease (AD), by virtue of their propensity to aggregate to form oligomers, fibrils, and eventually plaques in the brain. Nevertheless, they appear to be essential for correct neurophysiology on the synaptic level and may have additional functions including antimicrobial activity, sealing the blood-brain barrier, promotion of recovery from brain injury, and even tumor suppression. Aβ peptides are also avid copper chelators, and coincidentally copper is significantly dysregulated in the AD brain. Copper (Cu) is released in significant amounts during calcium signaling at the synaptic membrane. Aβ peptides may have a role in maintaining synaptic Cu homeostasis, including as a scavenger for redox-active Cu and as a chaperone for clearing Cu from the synaptic cleft. Here, we employed the Aβ1-16 and Aβ4-16 peptides as well-established non-aggregating models of major Aβ species in healthy and AD brains, and the Ctr1-14 peptide as a model for the extracellular domain of the human cellular copper transporter protein (Ctr1). With these model peptides and a number of spectroscopic techniques, we investigated whether the Cu complexes of Aβ peptides could provide Ctr1 with either Cu(II) or Cu(I). We found that Aβ1-16 fully and rapidly delivered Cu(II) to Ctr1-14 along the affinity gradient. Such delivery was only partial for the Aβ4-16/Ctr1-14 pair, in agreement with the higher complex stability for the former peptide. Moreover, the reaction was very slow and took ca. 40 h to reach equilibrium under the given experimental conditions. In either case of Cu(II) exchange, no intermediate (ternary) species were present in detectable amounts. In contrast, both Aβ species released Cu(I) to Ctr1-14 rapidly and in a quantitative fashion, but ternary intermediate species were detected in the analysis of XAS data. The results presented here are the first direct evidence of a Cu(I) and Cu(II) transfer between the human Ctr1 and Aβ model peptides. These results are discussed in terms of the fundamental difference between the peptides' Cu(II) complexes (pleiotropic ensemble of open structures of Aβ1-16 vs the rigid closed-ring system of amino-terminal Cu/Ni binding Aβ4-16) and the similarity of their Cu(I) complexes (both anchored at the tandem His13/His14, bis-His motif). These results indicate that Cu(I) may be more feasible than Cu(II) as the cargo for copper clearance from the synaptic cleft by Aβ peptides and its delivery to Ctr1. The arguments in favor of Cu(I) include the fact that cellular Cu export and uptake proteins (ATPase7A/B and Ctr1, respectively) specifically transport Cu(I), the abundance of extracellular ascorbate reducing agent in the brain, and evidence of a potential associative (hand-off) mechanism of Cu(I) transfer that may mirror the mechanisms of intracellular Cu chaperone proteins.
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Affiliation(s)
- Ewelina Stefaniak
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States.,Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - M Jake Pushie
- Department of Surgery, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Catherine Vaerewyck
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - David Corcelli
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Chloe Griggs
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Whitney Lewis
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Emma Kelley
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Noreen Maloney
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Madison Sendzik
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Kathryn L Haas
- Department of Chemistry and Physics, Saint Mary's College, Notre Dame, Indiana 46556, United States
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26
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Parodi‐Rullán R, Ghiso J, Cabrera E, Rostagno A, Fossati S. Alzheimer's amyloid β heterogeneous species differentially affect brain endothelial cell viability, blood-brain barrier integrity, and angiogenesis. Aging Cell 2020; 19:e13258. [PMID: 33155752 PMCID: PMC7681048 DOI: 10.1111/acel.13258] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/02/2020] [Accepted: 09/19/2020] [Indexed: 01/05/2023] Open
Abstract
Impaired clearance in the Alzheimer's Disease (AD) brain is key in the formation of Aβ parenchymal plaques and cerebrovascular deposits known as cerebral amyloid angiopathy (CAA), present in >80% of AD patients and ~50% of non-AD elderly subjects. Aβ deposits are highly heterogeneous, containing multiple fragments mostly derived from catabolism of Aβ40/Aβ42, which exhibit dissimilar aggregation properties. Remarkably, the role of these physiologically relevant Aβ species in cerebrovascular injury and their impact in vascular pathology is unknown. We sought to understand how heterogeneous Aβ species affect cerebral endothelial health and assess whether their diverse effects are associated with the peptides aggregation propensities. We analyzed cerebral microvascular endothelial cell (CMEC) viability, blood-brain barrier (BBB) permeability, and angiogenesis, all relevant aspects of brain microvascular dysfunction. We found that Aβ peptides and fragments exerted differential effects on cerebrovascular pathology. Peptides forming mostly oligomeric structures induced CMEC apoptosis, whereas fibrillar aggregates increased BBB permeability without apoptotic effects. Interestingly, all Aβ species tested inhibited angiogenesis in vitro. These data link the biological effects of the heterogeneous Aβ peptides to their primary structure and aggregation, strongly suggesting that the composition of amyloid deposits influences clinical aspects of the AD vascular pathology. As the presence of predominant oligomeric structures in proximity of the vessel walls may lead to CMEC death and induction of microhemorrhages, fibrillar amyloid is likely responsible for increased BBB permeability and associated neurovascular dysfunction. These results have the potential to unveil more specific therapeutic targets and clarify the multifactorial nature of AD.
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Affiliation(s)
- Rebecca Parodi‐Rullán
- Alzheimer's Center at Temple Lewis Katz School of Medicine Temple University Philadelphia PA USA
| | - Jorge Ghiso
- Department of Pathology New York University School of Medicine New York NY USA
- Department of Psychiatry New York University School of Medicine New York NY USA
| | - Erwin Cabrera
- Department of Pathology New York University School of Medicine New York NY USA
| | - Agueda Rostagno
- Department of Pathology New York University School of Medicine New York NY USA
| | - Silvia Fossati
- Alzheimer's Center at Temple Lewis Katz School of Medicine Temple University Philadelphia PA USA
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27
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Kumar S, Lemere CA, Walter J. Phosphorylated Aβ peptides in human Down syndrome brain and different Alzheimer's-like mouse models. Acta Neuropathol Commun 2020; 8:118. [PMID: 32727580 PMCID: PMC7388542 DOI: 10.1186/s40478-020-00959-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 05/30/2020] [Indexed: 12/12/2022] Open
Abstract
The deposition of neurotoxic amyloid-β (Aβ) peptides in extracellular plaques in the brain parenchyma is one of the most prominent neuropathological features of Alzheimer's disease (AD), and considered to be closely related to the pathogenesis of this disease. A number of recent studies demonstrate the heterogeneity in the composition of Aβ deposits in AD brains, due to the occurrence of elongated, truncated and post-translationally modified Aβ peptides that have peculiar characteristics in aggregation behavior and biostability. Importantly, the detection of modified Aβ species has been explored to characterize distinct stages of AD, with phosphorylated Aβ being present in the clinical phase of AD. People with Down syndrome (DS) develop AD pathology by 40 years of age likely due to the overproduction of Aβ caused by the additional copy of the gene encoding the amyloid precursor protein on chromosome 21. In the current study, we analysed the deposition of phosphorylated and non-phosphorylated Aβ species in human DS, AD, and control brains. In addition, deposition of these Aβ species was analysed in brains of a series of established transgenic AD mouse models using phosphorylation-state specific Aβ antibodies. Significant amounts of Aβ phosphorylated at serine residue 8 (pSer8Aβ) and unmodified Aβ were detected in the brains of DS and AD cases. The brains of different transgenic mouse models with either only human mutant amyloid precursor protein (APP), or combinations of human mutant APP, Presenilin (PS), and tau transgenes showed distinct age-dependent and spatiotemporal deposition of pSer8Aβ in extracellular plaques and within the vasculature. Together, these results demonstrate the deposition of phosphorylated Aβ species in DS brains, further supporting the similarity of Aβ deposition in AD and DS. Thus, the detection of phosphorylated and other modified Aβ species could contribute to the understanding and dissection of the complexity in the age-related and spatiotemporal deposition of Aβ variants in AD and DS as well as in distinct mouse models.
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28
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Dinkel F, Trujillo-Rodriguez D, Villegas A, Streffer J, Mercken M, Lopera F, Glatzel M, Sepulveda-Falla D. Decreased Deposition of Beta-Amyloid 1-38 and Increased Deposition of Beta-Amyloid 1-42 in Brain Tissue of Presenilin-1 E280A Familial Alzheimer's Disease Patients. Front Aging Neurosci 2020; 12:220. [PMID: 32848702 PMCID: PMC7399638 DOI: 10.3389/fnagi.2020.00220] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/22/2020] [Indexed: 01/01/2023] Open
Abstract
Familial Alzheimer's Disease (FAD) caused by Presenilin-1 (PS1) mutations is characterized by early onset, cognitive impairment, and dementia. Impaired gamma secretase function favors production of longer beta-amyloid species in PS1 FAD. The PS1 E280A mutation is the largest FAD kindred under study. Here, we studied beta-amyloid deposits in PS1 E280A FAD brains in comparison to sporadic Alzheimer's disease (SAD). We analyzed cortices and cerebellum from 10 FAD and 10 SAD brains using immunohistochemistry to determine total beta-amyloid, hyperphosphorylated tau (pTau), and specific beta-amyloid peptides 1-38, 1-40, 1-42, and 1-43. Additionally, we studied beta-amyloid subspecies by ELISA, and vessel pathology was detected with beta-amyloid 1-42 and truncated pyroglutamylated beta-amyloid antibodies. There were no significant differences in total beta-amyloid signal between SAD and FAD. Beta-amyloid 1-38 and 1-43 loads were increased, and 1-42 loads were decreased in frontal cortices of SAD when compared to FAD. Beta-amyloid species assessment by ELISA resembled our findings by immunohistochemical analysis. Differences in beta-amyloid 1-38 and 1-42 levels between SAD and FAD were evidenced by using beta-amyloid length-specific antibodies, reflecting a gamma secretase-dependent shift in beta-amyloid processing in FAD cases. The use of beta-amyloid length-specific antibodies for postmortem assessment of beta-amyloid pathology can differentiate between SAD and PS1 FAD cases and it can be useful for identification of SAD cases potentially affected with gamma secretase dysfunction.
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Affiliation(s)
- Felix Dinkel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf - UKE, Hamburg, Germany
| | | | - Andres Villegas
- Neuroscience Group of Antioquia, Faculty of Medicine, University of Antioquia, Medellín, Colombia
| | - Johannes Streffer
- Johnson & Johnson Pharmaceutical Research and Development, Janssen Pharmaceutica, Beerse, Belgium
| | - Marc Mercken
- Johnson & Johnson Pharmaceutical Research and Development, Janssen Pharmaceutica, Beerse, Belgium
| | - Francisco Lopera
- Neuroscience Group of Antioquia, Faculty of Medicine, University of Antioquia, Medellín, Colombia
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf - UKE, Hamburg, Germany
| | - Diego Sepulveda-Falla
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf - UKE, Hamburg, Germany
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29
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Zampar S, Klafki HW, Sritharen K, Bayer TA, Wiltfang J, Rostagno A, Ghiso J, Miles LA, Wirths O. N-terminal heterogeneity of parenchymal and vascular amyloid-β deposits in Alzheimer's disease. Neuropathol Appl Neurobiol 2020; 46:673-685. [PMID: 32497293 PMCID: PMC8082844 DOI: 10.1111/nan.12637] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/24/2020] [Indexed: 02/06/2023]
Abstract
Aims: The deposition of amyloid-β (Aβ) peptides in the form of extracellular plaques in the brain represents one of the classical hallmarks of Alzheimer’s disease (AD). In addition to ‘full-length’ Aβ starting with aspartic acid (Asp-1), considerable amounts of various shorter, N-terminally truncated Aβ peptides have been identified by mass spectrometry in autopsy samples from individuals with AD. Methods: Selectivity of several antibodies detecting full-length, total or N-terminally truncated Aβ species has been characterized with capillary isoelectric focusing assays using a set of synthetic Aβ peptides comprising different N-termini. We further assessed the N-terminal heterogeneity of extracellular and vascular Aβ peptide deposits in the human brain by performing immunohistochemical analyses using sporadic AD cases with antibodies targeting different N-terminal residues, including the biosimilar antibodies Bapineuzumab and Crenezumab. Results: While antibodies selectively recognizing Aβ1–x showed a much weaker staining of extracellular plaques and tended to accentuate cerebrovascular amyloid deposits, antibodies detecting Aβ starting with phenylalanine at position 4 of the Aβ sequence showed abundant amyloid plaque immunoreactivity in the brain parenchyma. The biosimilar antibody Bapineuzumab recognized Aβ starting at Asp-1 and demonstrated abundant immunoreactivity in AD brains. Discussion: In contrast to other studied Aβ1–x-specific antibodies, Bapineuzumab displayed stronger immunoreactivity on fixed tissue samples than with sodium dodecyl sulfate-denatured samples on Western blots. This suggests conformational preferences of this antibody. The diverse composition of plaques and vascular deposits stresses the importance of understanding the roles of various Aβ variants during disease development and progression in order to generate appropriate target-developed therapies.
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Affiliation(s)
- S Zampar
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Göttingen, Germany
| | - H W Klafki
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Göttingen, Germany
| | - K Sritharen
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Göttingen, Germany
| | - T A Bayer
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Göttingen, Germany
| | - J Wiltfang
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Göttingen, Germany.,Neurosciences and Signaling Group, Department of Medical Sciences, Institute of Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal.,German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany
| | - A Rostagno
- Departments of, Pathology, New York University School of Medicine, New York, NY, USA
| | - J Ghiso
- Departments of, Pathology, New York University School of Medicine, New York, NY, USA.,Department of, Psychiatry, New York University School of Medicine, New York, NY, USA
| | - L A Miles
- St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia
| | - O Wirths
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Göttingen, Germany
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30
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Karkisaval AG, Rostagno A, Azimov R, Ban DK, Ghiso J, Kagan BL, Lal R. Ion channel formation by N-terminally truncated Aβ (4-42): relevance for the pathogenesis of Alzheimer's disease. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2020; 29:102235. [PMID: 32531337 DOI: 10.1016/j.nano.2020.102235] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 05/27/2020] [Accepted: 05/29/2020] [Indexed: 11/17/2022]
Abstract
Aβ deposition is a pathological hallmark of Alzheimer's disease (AD). Besides the full-length amyloid forming peptides (Aβ1-40 and Aβ1-42), biochemical analyses of brain deposits have identified a variety of N- and C-terminally truncated Aβ variants in sporadic and familial AD patients. However, their relevance for AD pathogenesis remains largely understudied. We demonstrate that Aβ4-42 exhibits a high tendency to form β-sheet structures leading to fast self-aggregation and formation of oligomeric assemblies. Atomic force microscopy and electrophysiological studies reveal that Aβ4-42 forms highly stable ion channels in lipid membranes. These channels that are blocked by monoclonal antibodies specifically recognizing the N-terminus of Aβ4-42. An Aβ variant with a double truncation at phenylalanine-4 and leucine 34, (Aβ4-34), exhibits unstable channel formation capability. Taken together the results presented herein highlight the potential benefit of C-terminal proteolytic cleavage and further support an important pathogenic role for N-truncated Aβ species in AD pathophysiology.
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Affiliation(s)
- Abhijith G Karkisaval
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, 92092, USA
| | - Agueda Rostagno
- Department of Pathology, New York University Grossman School of Medicine, 550 First Avenue, New York, NY, 10016, USA
| | - Rustam Azimov
- Department of Psychiatry, Geffen School of Medicine, University of California, Los Angeles, California 90095, USA; Semel Neuropsychiatric for Neuroscience & Human Behavior, University of California, Los Angeles, California 90095, United States
| | - Deependra K Ban
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, 92092, USA
| | - Jorge Ghiso
- Department of Pathology, New York University Grossman School of Medicine, 550 First Avenue, New York, NY, 10016, USA; Department of Psychiatry, New York University Grossman School of Medicine, 550 First Avenue, New York, NY, 10016, USA.
| | - Bruce L Kagan
- Department of Psychiatry, Geffen School of Medicine, University of California, Los Angeles, California 90095, USA; Semel Neuropsychiatric for Neuroscience & Human Behavior, University of California, Los Angeles, California 90095, United States.
| | - Ratnesh Lal
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, 92092, USA; Department of Bioengineering, University of California San Diego, La Jolla, California, 92092, USA; Materials Science and Engineering, University of California San Diego, La Jolla, California, 92092, USA.
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31
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Hornung K, Zampar S, Engel N, Klafki H, Liepold T, Bayer TA, Wiltfang J, Jahn O, Wirths O. N-Terminal Truncated Aβ4-42 Is a Substrate for Neprilysin Degradation in vitro and in vivo. J Alzheimers Dis 2020; 67:849-858. [PMID: 30664509 DOI: 10.3233/jad-181134] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In sporadic Alzheimer's disease (AD), an imbalance between production and clearance of amyloid-β (Aβ) peptides seems to account for enhanced Aβ accumulation. The metalloprotease neprilysin (NEP) is an important Aβ degrading enzyme as shown by a variety of in vitro and in vivo studies. While the degradation of full-length Aβ peptides such as Aβ1-40 and Aβ1-42 is well established, it is less clear whether NEP is also capable of degrading N-terminally truncated Aβ species such as the common variant Aβ4-42. In the present report, we confirmed the degradation of Aβ4-x species by neprilysin using in vitro digestion and subsequent analysis using gel-based assays and mass spectrometry. By crossing Tg4-42 mice expressing only Aβ4-42 peptides with homozygous NEP-knock-out mice (NEP-/-), we were able to demonstrate that NEP deficiency increased hippocampal intraneuronal Aβ levels and aggravated neuron loss in the Tg4-42 transgenic mouse model of AD.
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Affiliation(s)
- Karen Hornung
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Goettingen, Germany
| | - Silvia Zampar
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Goettingen, Germany
| | - Nadine Engel
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Goettingen, Germany
| | - Hans Klafki
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Goettingen, Germany
| | - Thomas Liepold
- Max Planck Institute of Experimental Medicine, Proteomics Group, Goettingen, Germany
| | - Thomas A Bayer
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Goettingen, Germany
| | - Jens Wiltfang
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Goettingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), Goettingen, Germany.,Department of iBiMED, Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Olaf Jahn
- Max Planck Institute of Experimental Medicine, Proteomics Group, Goettingen, Germany
| | - Oliver Wirths
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, Goettingen, Germany
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Sotolongo K, Ghiso J, Rostagno A. Nrf2 activation through the PI3K/GSK-3 axis protects neuronal cells from Aβ-mediated oxidative and metabolic damage. ALZHEIMERS RESEARCH & THERAPY 2020; 12:13. [PMID: 31931869 PMCID: PMC6958642 DOI: 10.1186/s13195-019-0578-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 12/30/2019] [Indexed: 01/08/2023]
Abstract
Background Mounting evidence points to a crucial role of amyloid-β (Aβ) in the pathophysiology of Alzheimer’s disease (AD), a disorder in which brain glucose hypometabolism, downregulation of central elements of phosphorylation pathways, reduced ATP levels, and enhanced oxidative damage coexist, and sometimes precede, synaptic alterations and clinical manifestations. Since the brain has limited energy storage capacity, mitochondria play essential roles in maintaining the high levels of energy demand, but, as major consumers of oxygen, these organelles are also the most important generators of reactive oxygen species (ROS). Thus, it is not surprising that mitochondrial dysfunction is tightly linked to synaptic loss and AD pathophysiology. In spite of their relevance, the mechanistic links among ROS homeostasis, metabolic alterations, and cell bioenergetics, particularly in relation to Aβ, still remain elusive. Methods We have used classic biochemical and immunocytochemical approaches together with the evaluation of real-time changes in global energy metabolism in a Seahorse Metabolic Analyzer to provide insights into the detrimental role of oligAβ in SH-SY5Y and primary neurons testing their pharmacologic protection by small molecules. Results Our findings indicate that oligomeric Aβ induces a dramatic increase in ROS production and severely affects neuronal metabolism and bioenergetics. Assessment of global energy metabolism in real time demonstrated Aβ-mediated reduction in oxygen consumption affecting basal and maximal respiration and causing decreased ATP production. Pharmacologic targeting of Aβ-challenged neurons with a set of small molecules of known antioxidant and cytoprotective activity prevented the metabolic/bioenergetic changes induced by the peptide, fully restoring mitochondrial function while inducing an antioxidant response that counterbalanced the ROS production. Search for a mechanistic link among the protective small molecules tested identified the transcription factor Nrf2—compromised by age and downregulated in AD and transgenic models—as their main target and the PI3K/GSK-3 axis as the central pathway through which the compounds elicit their Aβ protective action. Conclusions Our study provides insights into the complex molecular mechanisms triggered by oligAβ which profoundly affect mitochondrial performance and argues for the inclusion of small molecules targeting the PI3K/GSK-3 axis and Nrf2-mediated pathways as part of the current or future combinatorial therapies.
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Affiliation(s)
- Krystal Sotolongo
- Department of Pathology, New York University School of Medicine, 550 First Avenue, New York, NY, 10016, USA
| | - Jorge Ghiso
- Department of Pathology, New York University School of Medicine, 550 First Avenue, New York, NY, 10016, USA. .,Department of Psychiatry, New York University School of Medicine, 550 First Avenue, New York, NY, 10016, USA.
| | - Agueda Rostagno
- Department of Pathology, New York University School of Medicine, 550 First Avenue, New York, NY, 10016, USA.
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Volloch V, Olsen B, Rits S. Alzheimer's Disease is Driven by Intraneuronally Retained Beta-Amyloid Produced in the AD-Specific, βAPP-Independent Pathway: Current Perspective and Experimental Models for Tomorrow. ANNALS OF INTEGRATIVE MOLECULAR MEDICINE 2020; 2:90-114. [PMID: 32617536 PMCID: PMC7331974 DOI: 10.33597/aimm.02-1007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
A view of the origin and progression of Alzheimer's disease, AD, prevailing until now and formalized as the Amyloid Cascade Hypothesis theory, maintains that the disease is initiated by overproduction of beta-amyloid, Aβ, which is generated solely by the Aβ precursor protein, βAPP, proteolytic pathway and secreted from the cell. Consequent extracellular accumulation of Aβ triggers a cascade of molecular and cellular events leading to neurodegeneration that starts early in life, progresses as one prolonged process, builds up for decades, and culminates in symptomatic manifestations of the disease late in life. In this paradigm, a time window for commencement of therapeutic intervention is small and accessible only early in life. The outlook introduced in the present study is fundamentally different. It posits that the βAPP proteolytic/secretory pathway of Aβ production causes AD in humans no more than it does in either short- or long-lived non-human mammals that share this pathway with humans, accumulate beta-amyloid as they age, but do not develop the disease. Alzheimer's disease, according to this outlook, is driven by an additional powerful AD-specific pathway of Aβ production that operates in affected humans, is completely independent of the βAPP precursor, and is not available in non-human mammals. The role of the βAPP proteolytic pathway in the disease in humans is activation of this additional AD-specific Aβ production pathway. This occurs through accumulation of intracellular Aβ, primarily via ApoE-assisted cellular uptake of secreted beta-amyloid, but also through retention of a fraction of Aβ produced in the βAPP proteolytic pathway. With time, accumulated intracellular Aβ triggers mitochondrial dysfunction. In turn, cellular stresses associated with mitochondrial dysfunction, including ER stress, activate a second, AD-specific, Aβ production pathway: Asymmetric RNA-dependent βAPP mRNA amplification; animal βAPP mRNA is ineligible for this process. In this pathway, every conventionally produced βAPP mRNA molecule serves potentially as a template for production of severely 5'-truncated mRNA encoding not the βAPP but its C99 fragment (hence "asymmetric"), the immediate precursor of Aβ. Thus produced, N-terminal signal peptide-lacking C99 is processed not in the secretory pathway on the plasma membrane, but at the intracellular membrane sites, apparently in a neuron-specific manner. The resulting Aβ is, therefore, not secreted but is retained intraneuronally and accumulates rapidly within the cell. Increased levels of intracellular Aβ augment mitochondrial dysfunction, which, in turn, sustains the activity of the βAPP mRNA amplification pathway. These self-propagating mutual Aβ overproduction/mitochondrial dysfunction feedback cycles constitute a formidable two-stroke engine, an engine that drives Alzheimer's disease. The present outlook envisions Alzheimer's disorder as a two-stage disease. The first stage is a slow process of intracellular beta-amyloid accumulation. It results neither in significant neurodegenerative damage, nor in manifestation of the disease. The second stage commences with the activation of the βAPP mRNA amplification pathway shortly before symptomatic onset of the disease, sharply increases the rate of Aβ generation and the extent of its intraneuronal accumulation, produces significant damages, triggers AD symptoms, and is fast. In this paradigm, the time window of therapeutic intervention is wide open, and preventive treatment can be initiated any time, even late in life, prior to commencement of the second stage of the disease. Moreover, there are good reasons to believe that with a drug blocking the βAPP mRNA amplification pathway, it would be possible not only to preempt the disease but also to stop and to reverse it even when early AD symptoms have already manifested. There are numerous experimental models of AD, all based on a notion of the exceptionality of βAPP proteolytic/secretory pathway in Aβ production in the disease. However, with no drug even remotely effective in Alzheimer's disease, a long list of candidate drugs that succeeded remarkably in animal models, yet failed utterly in human clinical trials of potential AD drugs, attests to the inadequacy of currently employed AD models. The concept of a renewable supply of beta-amyloid, produced in the βAPP mRNA amplification pathway and retained intraneuronally in Alzheimer's disease, explains spectacular failures of both BACE inhibition and Aβ-immunotherapy in human clinical trials. This concept also forms the basis of a new generation of animal and cell-based experimental models of AD, described in the present study. These models incorporate Aβ- or C99-encoding mRNA amplification pathways of Aβ production, as well as intracellular retention of their product, and can support not only further investigation of molecular mechanisms of AD but also screening for and testing of candidate drugs aimed at therapeutic targets suggested by the present study.
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Affiliation(s)
- Vladimir Volloch
- Department of Developmental Biology, Harvard School of Dental Medicine, USA
| | - Bjorn Olsen
- Department of Developmental Biology, Harvard School of Dental Medicine, USA
| | - Sophia Rits
- Division of Molecular Medicine, Children’s Hospital, Boston, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, USA
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Wirths O, Zampar S. Emerging roles of N- and C-terminally truncated Aβ species in Alzheimer’s disease. Expert Opin Ther Targets 2019; 23:991-1004. [DOI: 10.1080/14728222.2019.1702972] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Oliver Wirths
- Department of Psychiatry and Psychotherapy, Molecular Psychiatry, University Medical Center (UMG), Georg-August-University, Göttingen, Germany
| | - Silvia Zampar
- Department of Psychiatry and Psychotherapy, Molecular Psychiatry, University Medical Center (UMG), Georg-August-University, Göttingen, Germany
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Kirabali T, Rigotti S, Siccoli A, Liebsch F, Shobo A, Hock C, Nitsch RM, Multhaup G, Kulic L. The amyloid-β degradation intermediate Aβ34 is pericyte-associated and reduced in brain capillaries of patients with Alzheimer's disease. Acta Neuropathol Commun 2019; 7:194. [PMID: 31796114 PMCID: PMC6892233 DOI: 10.1186/s40478-019-0846-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 11/13/2019] [Indexed: 02/07/2023] Open
Abstract
An impairment of amyloid β-peptide (Aβ) clearance is suggested to play a key role in the pathogenesis of sporadic Alzheimer’s disease (AD). Amyloid degradation is mediated by various mechanisms including fragmentation by enzymes like neprilysin, matrix metalloproteinases (MMPs) and a recently identified amyloidolytic activity of β-site amyloid precursor protein cleaving enzyme 1 (BACE1). BACE1 cleavage of Aβ40 and Aβ42 results in the formation of a common Aβ34 intermediate which was found elevated in cerebrospinal fluid levels of patients at the earliest disease stages. To further investigate the role of Aβ34 as a marker for amyloid clearance in AD, we performed a systematic and comprehensive analysis of Aβ34 immunoreactivity in hippocampal and cortical post-mortem brain tissue from AD patients and non-demented elderly individuals. In early Braak stages, Aβ34 was predominantly detectable in a subset of brain capillaries associated with pericytes, while in later disease stages, in clinically diagnosed AD, this pericyte-associated Aβ34 immunoreactivity was largely lost. Aβ34 was also detected in isolated human cortical microvessels associated with brain pericytes and its levels correlated with Aβ40, but not with Aβ42 levels. Moreover, a significantly decreased Aβ34/Aβ40 ratio was observed in microvessels from AD patients in comparison to non-demented controls suggesting a reduced proteolytic degradation of Aβ40 to Aβ34 in AD. In line with the hypothesis that pericytes at the neurovascular unit are major producers of Aβ34, biochemical studies in cultured human primary pericytes revealed a time and dose dependent increase of Aβ34 levels upon treatment with recombinant Aβ40 peptides while Aβ34 production was impaired when Aβ40 uptake was reduced or BACE1 activity was inhibited. Collectively, our findings indicate that Aβ34 is generated by a novel BACE1-mediated Aβ clearance pathway in pericytes of brain capillaries. As amyloid clearance is significantly reduced in AD, impairment of this pathway might be a major driver of the pathogenesis in sporadic AD.
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Stefaniak E, Bal W. Cu II Binding Properties of N-Truncated Aβ Peptides: In Search of Biological Function. Inorg Chem 2019; 58:13561-13577. [PMID: 31304745 DOI: 10.1021/acs.inorgchem.9b01399] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
As life expectancy increases, the number of people affected by progressive and irreversible dementia, Alzheimer's Disease (AD), is predicted to grow. No drug designs seem to be working in humans, apparently because the origins of AD have not been identified. Invoking amyloid cascade, metal ions, and ROS production hypothesis of AD, herein we share our point of view on Cu(II) binding properties of Aβ4-x, the most prevalent N-truncated Aβ peptide, currently known as the main constituent of amyloid plaques. The capability of Aβ4-x to rapidly take over copper from previously tested Aβ1-x peptides and form highly stable complexes, redox unreactive and resistant to copper exchange reactions, prompted us to propose physiological roles for these peptides. We discuss the new findings on the reactivity of Cu(II)Aβ4-x with coexisting biomolecules in the context of synaptic cleft; we suggest that the role of Aβ4-x peptides is to quench Cu(II) toxicity in the brain and maintain neurotransmission.
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Affiliation(s)
- Ewelina Stefaniak
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
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Walter S, Jumpertz T, Hüttenrauch M, Ogorek I, Gerber H, Storck SE, Zampar S, Dimitrov M, Lehmann S, Lepka K, Berndt C, Wiltfang J, Becker-Pauly C, Beher D, Pietrzik CU, Fraering PC, Wirths O, Weggen S. The metalloprotease ADAMTS4 generates N-truncated Aβ4-x species and marks oligodendrocytes as a source of amyloidogenic peptides in Alzheimer's disease. Acta Neuropathol 2019; 137:239-257. [PMID: 30426203 DOI: 10.1007/s00401-018-1929-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 10/17/2018] [Accepted: 11/04/2018] [Indexed: 02/06/2023]
Abstract
Brain accumulation and aggregation of amyloid-β (Aβ) peptides is a critical step in the pathogenesis of Alzheimer's disease (AD). Full-length Aβ peptides (mainly Aβ1-40 and Aβ1-42) are produced through sequential proteolytic cleavage of the amyloid precursor protein (APP) by β- and γ-secretases. However, studies of autopsy brain samples from AD patients have demonstrated that a large fraction of insoluble Aβ peptides are truncated at the N-terminus, with Aβ4-x peptides being particularly abundant. Aβ4-x peptides are highly aggregation prone, but their origin and any proteases involved in their generation are unknown. We have identified a recognition site for the secreted metalloprotease ADAMTS4 (a disintegrin and metalloproteinase with thrombospondin motifs 4) in the Aβ peptide sequence, which facilitates Aβ4-x peptide generation. Inducible overexpression of ADAMTS4 in HEK293 cells resulted in the secretion of Aβ4-40 but unchanged levels of Aβ1-x peptides. In the 5xFAD mouse model of amyloidosis, Aβ4-x peptides were present not only in amyloid plaque cores and vessel walls, but also in white matter structures co-localized with axonal APP. In the ADAMTS4-/- knockout background, Aβ4-40 levels were reduced confirming a pivotal role of ADAMTS4 in vivo. Surprisingly, in the adult murine brain, ADAMTS4 was exclusively expressed in oligodendrocytes. Cultured oligodendrocytes secreted a variety of Aβ species, but Aβ4-40 peptides were absent in cultures derived from ADAMTS4-/- mice indicating that the enzyme was essential for Aβ4-x production in this cell type. These findings establish an enzymatic mechanism for the generation of Aβ4-x peptides. They further identify oligodendrocytes as a source of these highly amyloidogenic Aβ peptides.
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Bossak-Ahmad K, Mital M, Płonka D, Drew SC, Bal W. Oligopeptides Generated by Neprilysin Degradation of β-Amyloid Have the Highest Cu(II) Affinity in the Whole Aβ Family. Inorg Chem 2018; 58:932-943. [PMID: 30582328 DOI: 10.1021/acs.inorgchem.8b03051] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The catabolism of β-amyloid (Aβ) is carried out by numerous endopeptidases including neprilysin, which hydrolyzes peptide bonds preceding positions 4, 10, and 12 to yield Aβ4-9 and a minor Aβ12- x species. Alternative processing of the amyloid precursor protein by β-secretase also generates the Aβ11- x species. All these peptides contain a Xxx-Yyy-His sequence, also known as an ATCUN or NTS motif, making them strong chelators of Cu(II) ions. We synthesized the corresponding peptides, Phe-Arg-His-Asp-Ser-Gly-OH (Aβ4-9), Glu-Val-His-His-Gln-Lys-am (Aβ11-16), Val-His-His-Gln-Lys-am (Aβ12-16), and pGlu-Val-His-His-Gln-Lys-am (pAβ11-16), and investigated their Cu(II) binding properties using potentiometry, and UV-vis, circular dichroism, and electron paramagnetic resonance spectroscopies. We found that the three peptides with unmodified N-termini formed square-planar Cu(II) complexes at pH 7.4 with analogous geometries but significantly varied Kd values of 6.6 fM (Aβ4-9), 9.5 fM (Aβ12-16), and 1.8 pM (Aβ11-16). Cyclization of the N-terminal Glu11 residue to the pyroglutamate species pAβ11-16 dramatically reduced the affinity (5.8 nM). The Cu(II) affinities of Aβ4-9 and Aβ12-16 are the highest among the Cu(II) complexes of Aβ peptides. Using fluorescence spectroscopy, we demonstrated that the Cu(II) exchange between the Phe-Arg-His and Val-His-His motifs is very slow, on the order of days. These results are discussed in terms of the relevance of Aβ4-9, a major Cu(II) binding Aβ fragment generated by neprilysin, as a possible Cu(II) carrier in the brain.
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Affiliation(s)
- Karolina Bossak-Ahmad
- Institute of Biochemistry and Biophysics , Polish Academy of Sciences , 02-106 Warsaw , Poland
| | - Mariusz Mital
- Institute of Biochemistry and Biophysics , Polish Academy of Sciences , 02-106 Warsaw , Poland
| | - Dawid Płonka
- Institute of Biochemistry and Biophysics , Polish Academy of Sciences , 02-106 Warsaw , Poland
| | - Simon C Drew
- Institute of Biochemistry and Biophysics , Polish Academy of Sciences , 02-106 Warsaw , Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics , Polish Academy of Sciences , 02-106 Warsaw , Poland
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Liu J, Zhang W, Tao Y, Li LY. Induction of Beta-amyloid Protein by Sevoflurane Is Associated with Cognitive Impairment During Anesthesia in Aged Rats. INT J PHARMACOL 2018. [DOI: 10.3923/ijp.2018.1080.1086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Dunys J, Valverde A, Checler F. Are N- and C-terminally truncated Aβ species key pathological triggers in Alzheimer's disease? J Biol Chem 2018; 293:15419-15428. [PMID: 30143530 DOI: 10.1074/jbc.r118.003999] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The histopathology of Alzheimer's disease (AD) is characterized by neuronal loss, neurofibrillary tangles, and senile plaque formation. The latter results from an exacerbated production (familial AD cases) or altered degradation (sporadic cases) of 40/42-amino acid-long β-amyloid peptides (Aβ peptides) that are produced by sequential cleavages of Aβ precursor protein (βAPP) by β- and γ-secretases. The amyloid cascade hypothesis proposes a key role for the full-length Aβ42 and the Aβ40/42 ratio in AD etiology, in which soluble Aβ oligomers lead to neurotoxicity, tau hyperphosphorylation, aggregation, and, ultimately, cognitive defects. However, following this postulate, during the last decade, several clinical approaches aimed at decreasing full-length Aβ42 production or neutralizing it by immunotherapy have failed to reduce or even stabilize AD-related decline. Thus, the Aβ peptide (Aβ40/42)-centric hypothesis is probably a simplified view of a much more complex situation involving a multiplicity of APP fragments and Aβ catabolites. Indeed, biochemical analyses of AD brain deposits and fluids have unraveled an Aβ peptidome consisting of additional Aβ-related species. Such Aβ catabolites could be due to either primary enzymatic cleavages of βAPP or secondary processing of Aβ itself by exopeptidases. Here, we review the diversity of N- and C-terminally truncated Aβ peptides and their biosynthesis and outline their potential function/toxicity. We also highlight their potential as new pharmaceutical targets and biomarkers.
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Affiliation(s)
- Julie Dunys
- From the Université Côte d'Azur, INSERM, CNRS, IPMC, Team labeled "Laboratory of Excellence (LABEX) Distalz," 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France
| | - Audrey Valverde
- From the Université Côte d'Azur, INSERM, CNRS, IPMC, Team labeled "Laboratory of Excellence (LABEX) Distalz," 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France
| | - Frédéric Checler
- From the Université Côte d'Azur, INSERM, CNRS, IPMC, Team labeled "Laboratory of Excellence (LABEX) Distalz," 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France
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Sumner IL, Edwards RA, Asuni AA, Teeling JL. Antibody Engineering for Optimized Immunotherapy in Alzheimer's Disease. Front Neurosci 2018; 12:254. [PMID: 29740272 PMCID: PMC5924811 DOI: 10.3389/fnins.2018.00254] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/03/2018] [Indexed: 12/17/2022] Open
Abstract
There are nearly 50 million people with Alzheimer's disease (AD) worldwide and currently no disease modifying treatment is available. AD is characterized by deposits of Amyloid-β (Aβ), neurofibrillary tangles, and neuroinflammation, and several drug discovery programmes studies have focussed on Aβ as therapeutic target. Active immunization and passive immunization against Aβ leads to the clearance of deposits in humans and transgenic mice expressing human Aβ but have failed to improve memory loss. This review will discuss the possible explanations for the lack of efficacy of Aβ immunotherapy, including the role of a pro-inflammatory response and subsequent vascular side effects, the binding site of therapeutic antibodies and the timing of the treatment. We further discuss how antibodies can be engineered for improved efficacy.
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Affiliation(s)
- Isabelle L Sumner
- Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Ross A Edwards
- Biological Sciences, University of Southampton, Southampton, United Kingdom
| | | | - Jessica L Teeling
- Biological Sciences, University of Southampton, Southampton, United Kingdom
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Sgarlata C, Arena G, Bonomo RP, Giuffrida A, Tabbì G. Simple and mixed complexes of copper(II) with 8-hydroxyquinoline derivatives and amino acids: Characterization in solution and potential biological implications. J Inorg Biochem 2018; 180:89-100. [DOI: 10.1016/j.jinorgbio.2017.12.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/01/2017] [Accepted: 12/04/2017] [Indexed: 12/12/2022]
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Fang G, Wang H, Bian Z, Sun J, Liu A, Fang H, Liu B, Yao Q, Wu Z. Recent development of boronic acid-based fluorescent sensors. RSC Adv 2018; 8:29400-29427. [PMID: 35548017 PMCID: PMC9084483 DOI: 10.1039/c8ra04503h] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 08/08/2018] [Indexed: 11/21/2022] Open
Abstract
As Lewis acids, boronic acids can bind with 1,2- or 1,3-diols in aqueous solution reversibly and covalently to form five or six cyclic esters, thus resulting in significant fluorescence changes. Based on this phenomenon, boronic acid compounds have been well developed as sensors to recognize carbohydrates or other substances. Several reviews in this area have been reported before, however, novel boronic acid-based fluorescent sensors have emerged in large numbers in recent years. This paper reviews new boron-based sensors from the last five years that can detect carbohydrates such as glucose, ribose and sialyl Lewis A/X, and other substances including catecholamines, reactive oxygen species, and ionic compounds. And emerging electrochemically related fluorescent sensors and functionalized boronic acid as new materials including nanoparticles, smart polymer gels, and quantum dots were also involved. By summarizing and discussing these newly developed sensors, we expect new inspiration in the design of boronic acid-based fluorescent sensors. As Lewis acids, boronic acids can bind with 1,2- or 1,3-diols in aqueous solution reversibly and covalently to form five or six cyclic esters, thus resulting in significant fluorescence changes.![]()
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Affiliation(s)
- Guiqian Fang
- School of Medicine and Life Sciences
- University of Jinan-Shandong Academy of Medical Sciences
- Jinan 250200
- China
- Institute of Materia Medica
| | - Hao Wang
- School of Medicine and Life Sciences
- University of Jinan-Shandong Academy of Medical Sciences
- Jinan 250200
- China
- Institute of Materia Medica
| | - Zhancun Bian
- School of Medicine and Life Sciences
- University of Jinan-Shandong Academy of Medical Sciences
- Jinan 250200
- China
- Institute of Materia Medica
| | - Jie Sun
- School of Medicine and Life Sciences
- University of Jinan-Shandong Academy of Medical Sciences
- Jinan 250200
- China
- Institute of Materia Medica
| | - Aiqin Liu
- School of Medicine and Life Sciences
- University of Jinan-Shandong Academy of Medical Sciences
- Jinan 250200
- China
- Institute of Materia Medica
| | - Hao Fang
- Department of Medicinal Chemistry
- School of Pharmaceutical Sciences
- Shandong University
- Jinan
- China
| | - Bo Liu
- School of Medicine and Life Sciences
- University of Jinan-Shandong Academy of Medical Sciences
- Jinan 250200
- China
- Institute of Materia Medica
| | - Qingqiang Yao
- School of Medicine and Life Sciences
- University of Jinan-Shandong Academy of Medical Sciences
- Jinan 250200
- China
- Institute of Materia Medica
| | - Zhongyu Wu
- School of Medicine and Life Sciences
- University of Jinan-Shandong Academy of Medical Sciences
- Jinan 250200
- China
- Institute of Materia Medica
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Abstract
Amyloid β (Aβ) is the major constituent of the brain deposits found in parenchymal plaques and cerebral blood vessels of patients with Alzheimer's disease (AD). Besides classic full-length peptides, biochemical analyses of brain deposits have revealed high degree of Aβ heterogeneity likely resulting from the action of multiple proteolytic enzymes. This chapter describes a sequential extraction protocol allowing the differential fractionation of soluble and deposited Aβ species taking advantage of their differential solubility properties. Soluble Aβ is extracted by water-based buffers like phosphate-buffered saline-PBS-whereas pre-fibrillar and fibrillar deposits, usually poorly soluble in PBS, are extractable in detergent containing solutions or more stringent conditions as formic acid. The extraction procedure is followed by the biochemical identification of the extracted Aβ species using Western blot and a targeted proteomic analysis which combines immunoprecipitation with MALDI-ToF mass spectrometry. This approach revealed the presence of numerous C- and N-terminal truncated Aβ species in addition to Aβ1-40/42. Notably, the more soluble C-terminal cleaved fragments constitute a main part of PBS homogenates. On the contrary, N-terminal truncated species typically require more stringent conditions for the extraction in agreement with their lower solubility and enhanced aggregability. Detailed assessment of the molecular diversity of Aβ species composing interstitial fluid and amyloid deposits at different disease stages, as well as the evaluation of the truncation profile during various pharmacologic approaches will provide a comprehensive understanding of the still undefined contribution of Aβ truncations to AD pathogenesis and their potential as novel therapeutic targets.
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Affiliation(s)
- Agueda Rostagno
- Department of Pathology, New York University School of Medicine, New York, NY, USA
| | - Thomas A Neubert
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, NY, USA
| | - Jorge Ghiso
- Department of Pathology, New York University School of Medicine, New York, NY, USA.
- Department of Psychiatry, New York University School of Medicine, New York, NY, USA.
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45
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Scheidt HA, Adler J, Zeitschel U, Höfling C, Korn A, Krueger M, Roßner S, Huster D. Pyroglutamate-Modified Amyloid β (11- 40) Fibrils Are More Toxic than Wildtype Fibrils but Structurally Very Similar. Chemistry 2017; 23:15834-15838. [DOI: 10.1002/chem.201703909] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Holger A. Scheidt
- Institute for Medical Physics and Biophysics; Leipzig University; Härtelstr. 16-18 04107 Leipzig Germany
| | - Juliane Adler
- Institute for Medical Physics and Biophysics; Leipzig University; Härtelstr. 16-18 04107 Leipzig Germany
| | - Ulrike Zeitschel
- Paul Flechsig Institute for Brain Research; Leipzig University; Liebigstr. 19 04103 Leipzig Germany
| | - Corinna Höfling
- Paul Flechsig Institute for Brain Research; Leipzig University; Liebigstr. 19 04103 Leipzig Germany
| | - Alexander Korn
- Institute for Medical Physics and Biophysics; Leipzig University; Härtelstr. 16-18 04107 Leipzig Germany
| | - Martin Krueger
- Institute of Anatomy; Leipzig University; Eilenburger Str. 14-15 04317 Leipzig Germany
| | - Steffen Roßner
- Paul Flechsig Institute for Brain Research; Leipzig University; Liebigstr. 19 04103 Leipzig Germany
| | - Daniel Huster
- Institute for Medical Physics and Biophysics; Leipzig University; Härtelstr. 16-18 04107 Leipzig Germany
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