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Thieu MT, Shin J, Ogawa T, Park EJ, Kwon J, Ha TH, Kim YH, Ahn SJ. Scanning electron microscopy imaging of insulin amyloid fibrils directly grown on silicon substrate: A suggestion for complementary imaging strategy. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Minh Thu Thieu
- Korea Research Institute of Standards and Science (KRISS) Yuseong‐gu, Daejeon Republic of Korea
- Major of Nano Science Korea University of Science and Technology (UST) Yuseong‐gu, Daejeon Republic of Korea
| | - Jihoon Shin
- Core Research Facility & Analysis Center Korea Research Institute of Bioscience and Biotechnology (KRIBB) Yuseong‐gu, Daejeon Republic of Korea
| | - Takashi Ogawa
- Korea Research Institute of Standards and Science (KRISS) Yuseong‐gu, Daejeon Republic of Korea
- Major of Nano Science Korea University of Science and Technology (UST) Yuseong‐gu, Daejeon Republic of Korea
| | - Eun Jin Park
- Core Research Facility & Analysis Center Korea Research Institute of Bioscience and Biotechnology (KRIBB) Yuseong‐gu, Daejeon Republic of Korea
- Department of Nanobiotechnology, KRIBB School of Biotechnology Korea University of Science and Technology (UST) Yuseong‐gu, Daejeon Republic of Korea
| | - Ji‐Hwan Kwon
- Korea Research Institute of Standards and Science (KRISS) Yuseong‐gu, Daejeon Republic of Korea
- Major of Nano Science Korea University of Science and Technology (UST) Yuseong‐gu, Daejeon Republic of Korea
| | - Tai Hwan Ha
- Core Research Facility & Analysis Center Korea Research Institute of Bioscience and Biotechnology (KRIBB) Yuseong‐gu, Daejeon Republic of Korea
- Department of Nanobiotechnology, KRIBB School of Biotechnology Korea University of Science and Technology (UST) Yuseong‐gu, Daejeon Republic of Korea
| | - Young Heon Kim
- Graduate School of Analytical Science and Technology (GRAST) Chungnam National University Yuseong‐gu, Daejeon Republic of Korea
| | - Sang Jung Ahn
- Korea Research Institute of Standards and Science (KRISS) Yuseong‐gu, Daejeon Republic of Korea
- Major of Nano Science Korea University of Science and Technology (UST) Yuseong‐gu, Daejeon Republic of Korea
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McLaren DG, Shah V, Wisniewski T, Ghislain L, Liu C, Zhang H, Saldanha SA. High-Throughput Mass Spectrometry for Hit Identification: Current Landscape and Future Perspectives. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2021; 26:168-191. [PMID: 33482074 DOI: 10.1177/2472555220980696] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
For nearly two decades mass spectrometry has been used as a label-free, direct-detection method for both functional and affinity-based screening of a wide range of therapeutically relevant target classes. Here, we present an overview of several established and emerging mass spectrometry platforms and summarize the unique strengths and performance characteristics of each as they apply to high-throughput screening. Multiple examples from the recent literature are highlighted in order to illustrate the power of each individual technique, with special emphasis given to cases where the use of mass spectrometry was found to be differentiating when compared with other detection formats. Indeed, as many of these examples will demonstrate, the inherent strengths of mass spectrometry-sensitivity, specificity, wide dynamic range, and amenability to complex matrices-can be leveraged to enhance the discriminating power and physiological relevance of assays included in screening cascades. It is our hope that this review will serve as a useful guide to readers of all backgrounds and experience levels on the applicability and benefits of mass spectrometry in the search for hits, leads, and, ultimately, drugs.
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Friedemann M, Tõugu V, Palumaa P. Copper(II) partially protects three histidine residues and the N-terminus of amyloid-β peptide from diethyl pyrocarbonate (DEPC) modification. FEBS Open Bio 2020; 10:1072-1081. [PMID: 32255544 PMCID: PMC7262909 DOI: 10.1002/2211-5463.12857] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 03/09/2020] [Accepted: 03/31/2020] [Indexed: 11/07/2022] Open
Abstract
Diethyl pyrocarbonate (DEPC) has been primarily used as a residue‐specific modifying agent to study the role of His residues in peptide/protein and enzyme function; however, its action is not specific, and several other residues can also be modified. In the current study, we monitored the reaction of DEPC with amyloid‐beta (Aβ) peptides and insulin by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) and determined the modification sites by electrospray ionization quadrupole time‐of‐flight tandem MS (ESI Q‐TOF MS/MS). Our results indicate that five residues in Aβ1–42 are modified in the presence of 30‐fold molar excess of DEPC. After hydroxylamine treatment (which removes modifications from three His residues), two labels remain bound at the peptide N terminus and Lys16. DEPC treatment of Aβ1–42 promotes peptide aggregation, as monitored through the loss of soluble Aβ42 in a semi‐quantitative MALDI‐TOF MS assay. It has been previously proposed that Cu(II) ions protect Aβ1–16 from DEPC modification through binding to His6. We confirmed that Cu(II) ions decrease the stoichiometry of Aβ1–16 modification with the excess of DEPC being lower as compared to the control, which indicates that Cu(II) protects Aβ from DEPC modification. Sequencing of obtained Cu(II)‐protected Aβ1–16 samples showed that Cu(II) does not protect any residues completely, but partially protects all three His residues and the N terminus. Thus, the protection by Cu(II) ions is not related to specific metal binding to a particular residue (e.g. His6), but rather all His residues and the N terminus are involved in binding of Cu(II) ions. These results allow us to elucidate the effect of DEPC modification on amyloidogenity of human Aβ and to speculate about the role of His residues in these processes.
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Affiliation(s)
- Merlin Friedemann
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Estonia
| | - Vello Tõugu
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Estonia
| | - Peep Palumaa
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Estonia
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4
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Al-Edresi S, Alsalahat I, Freeman S, Aojula H, Penny J. Resveratrol-mediated cleavage of amyloid β 1-42 peptide: potential relevance to Alzheimer's disease. Neurobiol Aging 2020; 94:24-33. [PMID: 32512325 DOI: 10.1016/j.neurobiolaging.2020.04.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 04/08/2020] [Accepted: 04/10/2020] [Indexed: 11/30/2022]
Abstract
Aggregation of amyloid β1-42 (Aβ1-42) peptide within the brain is considered one of the main causes of the neuropathological changes associated with Alzheimer's disease. Resveratrol is a well-known antioxidant but has also been reported to bind to Aβ1-42 peptide, thereby reducing aggregation. However, little is known of the precise mechanism by which resveratrol reduces Aβ1-42 peptide aggregation. Using the thioflavin-T assay, the ability of resveratrol to reduce the extent of Aβ1-42 peptide aggregation was investigated. The findings of the present study demonstrate that interaction of resveratrol with Aβ1-42 peptide resulted in the cleavage of Aβ1-42 peptide into smaller fragments, as detected by matrix assisted laser desorption ionization-time of flight mass spectrometry. Atomic force microscopy analyses revealed Aβ1-42 peptide, under control conditions, aggregated into oligomers, protofibrils, and fibrils, whereas there was a distinct lack of these structures when Aβ1-42 peptide was incubated with resveratrol. Following 10 days incubation of Aβ1-42 peptide with resveratrol, particles with a mean z-height of 1.940 nm (range 0.675-3.275 nm) were observed, which are characteristic of shorter peptide species. In cell-based studies, resveratrol significantly reduced the cytotoxicity of Aβ1-42 peptide toward SH-SY5Y human neuroblastoma cells, suggesting a protective effect of the polyphenol. We therefore propose a novel mechanism by which resveratrol disrupts Aβ1-42 aggregation by mediating fragmentation of Aβ1-42 into smaller peptides, which have no propensity to aggregate further.
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Affiliation(s)
- Sarmad Al-Edresi
- Division of Pharmacy & Optometry, School of Health Sciences, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK; Faculty of Pharmacy, University of Kufa, Najaf, Iraq.
| | - Izzeddin Alsalahat
- Division of Pharmacy & Optometry, School of Health Sciences, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - Sally Freeman
- Division of Pharmacy & Optometry, School of Health Sciences, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - Harmesh Aojula
- Division of Pharmacy & Optometry, School of Health Sciences, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
| | - Jeffrey Penny
- Division of Pharmacy & Optometry, School of Health Sciences, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, UK
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5
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Machálková M, Schejbal J, Glatz Z, Preisler J. A label-free MALDI TOF MS-based method for studying the kinetics and inhibitor screening of the Alzheimer’s disease drug target β-secretase. Anal Bioanal Chem 2018; 410:7441-7448. [DOI: 10.1007/s00216-018-1354-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/21/2018] [Accepted: 08/30/2018] [Indexed: 01/19/2023]
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6
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Saha I, Singh V, Burra G, Thakur AK. Osmolytes modulate polyglutamine aggregation in a sequence dependent manner. J Pept Sci 2018; 24:e3115. [DOI: 10.1002/psc.3115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 06/18/2018] [Accepted: 06/22/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Itika Saha
- Department of Cellular Biochemistry; Max Planck Institute of Biochemistry; Martinsried Germany
- Department of Biological Sciences and Bioengineering; Indian Institute of Technology Kanpur; Kanpur India
| | - Virender Singh
- Department of Biological Sciences and Bioengineering; Indian Institute of Technology Kanpur; Kanpur India
| | - Gunasekhar Burra
- Department of Biological Sciences and Bioengineering; Indian Institute of Technology Kanpur; Kanpur India
| | - Ashwani Kumar Thakur
- Department of Biological Sciences and Bioengineering; Indian Institute of Technology Kanpur; Kanpur India
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7
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Krishtal J, Bragina O, Metsla K, Palumaa P, Tõugu V. In situ fibrillizing amyloid-beta 1-42 induces neurite degeneration and apoptosis of differentiated SH-SY5Y cells. PLoS One 2017; 12:e0186636. [PMID: 29065138 PMCID: PMC5655426 DOI: 10.1371/journal.pone.0186636] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 10/04/2017] [Indexed: 11/22/2022] Open
Abstract
The progression of Alzheimer’s disease is causatively linked to the accumulation of amyloid-β aggregates in the brain, however, it is not clear how the amyloid aggregates initiate the death of neuronal cells. The in vitro toxic effects of amyloid peptides are most commonly examined using the human neuroblastoma derived SH-SY5Y cell line and here we show that differentiated neuron-like SH-SY5Y cells are more sensitive to amyloid peptides than non-differentiated cells, because the latter lack long neurites. Exogenous soluble amyloid-β 1–42 covered cell bodies and whole neurites in differentiated cells with dense fibrils, causing neurite beading and fragmentation, whereas preformed amyloid-β 1–42 fibrils had no toxic effects. Importantly, spontaneously fibrillizing amyloid-β 1–42 peptide exhibited substantially higher cellular toxicity than amyloid-β 1–40, which did not form fibrils under the experimental conditions. These results support the hypothesis that peptide toxicity is related to the active fibrillization process in the incubation mixture.
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Affiliation(s)
- Jekaterina Krishtal
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
- * E-mail:
| | - Olga Bragina
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Kristel Metsla
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Peep Palumaa
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Vello Tõugu
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
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8
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Pihlasalo S, Deguchi T, Virtamo M, Jacobino J, Chary K, López-Picón FR, Brunhofer-Bolzer G, Huttunen R, Fallarero A, Vuorela P, Härmä H. Luminometric Nanoparticle-Based Assay for High Sensitivity Detection of β-Amyloid Aggregation. Anal Chem 2017; 89:2398-2404. [PMID: 28219250 DOI: 10.1021/acs.analchem.6b04266] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A nanoparticle-based assay utilizing time-resolved luminescence resonance energy transfer (TR-LRET) was developed for the detection of β-amyloid aggregation. The assay is based on the competitive adsorption of the sample and the acceptor-labeled protein to donor europium(III) polystyrene nanoparticles. The performance of the assay was demonstrated by following the fibrillization of β-amyloid peptide 1-42 (Aβ42) as a function of time and by comparing to the reference methods atomic force microscopy (AFM) and thioflavin T (ThT) assay. The fibrillization leads to reduced adsorption of Aβ42 to the nanoparticles increasing the TR-LRET signal. The investigated methods detected fibril formation with equal sensitivities. Eight potential fibrillization inhibitor compounds reported in the literature were tested and the results obtained with each method were compared. It was shown with AFM imaging that the inhibition of fibril formation was not complete with any of the compounds. The developed TR-LRET nanoparticle assay gave corresponding results with the AFM imaging. However, the ThT assay led to contradictory results, as low fluorescence signal was measured in the presence of all tested compounds suggesting inhibition of fibrillization. Our results suggest that the developed TR-LRET nanoparticle assay can be exploited for screening of potential β-amyloid aggregation inhibitors, whereas some of the tested compounds may be measured as false positive inhibitors with the much-utilized ThT assay.
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Affiliation(s)
- Sari Pihlasalo
- Laboratory of Materials Chemistry and Chemical Analysis, Department of Chemistry, University of Turku , Vatselankatu 2, FI-20500 Turku, Finland.,Laboratory of Biophysics, Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku , Tykistökatu 6A, FI-20520 Turku, Finland
| | - Takahiro Deguchi
- Laboratory of Biophysics, Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku , Tykistökatu 6A, FI-20520 Turku, Finland
| | - Maria Virtamo
- Laboratory of Biophysics, Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku , Tykistökatu 6A, FI-20520 Turku, Finland
| | - Jenna Jacobino
- Laboratory of Biophysics, Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku , Tykistökatu 6A, FI-20520 Turku, Finland
| | - Karthik Chary
- Laboratory of Biophysics, Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku , Tykistökatu 6A, FI-20520 Turku, Finland
| | - Francisco R López-Picón
- PET Preclinical Imaging Laboratory, Turku PET Centre, University of Turku , Itäinen Pitkäkatu 4B, FI-20520 Turku, Finland
| | - Gerda Brunhofer-Bolzer
- Department of Medicinal Chemistry, University of Vienna , Althanstrasse 14, A-1090 Vienna, Austria
| | - Roope Huttunen
- Laboratory of Biophysics, Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku , Tykistökatu 6A, FI-20520 Turku, Finland
| | - Adyary Fallarero
- Pharmaceutical Design and Discovery Group (PharmDD), Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki , Viikinkaari 5E, FI-00014 Helsinki, Finland
| | - Pia Vuorela
- Pharmaceutical Design and Discovery Group (PharmDD), Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki , Viikinkaari 5E, FI-00014 Helsinki, Finland
| | - Harri Härmä
- Laboratory of Materials Chemistry and Chemical Analysis, Department of Chemistry, University of Turku , Vatselankatu 2, FI-20500 Turku, Finland.,Laboratory of Biophysics, Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku , Tykistökatu 6A, FI-20520 Turku, Finland
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9
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Bastos P, Trindade F, Leite-Moreira A, Falcão-Pires I, Ferreira R, Vitorino R. Methodological approaches and insights on protein aggregation in biological systems. Expert Rev Proteomics 2016; 14:55-68. [DOI: 10.1080/14789450.2017.1264877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Paulo Bastos
- Department of Medical Sciences, Institute of Biomedicine – iBiMED, University of Aveiro, Aveiro, Portugal
- Department of Chemistry, University of Aveiro, Aveiro, Portugal
| | - Fábio Trindade
- Department of Medical Sciences, Institute of Biomedicine – iBiMED, University of Aveiro, Aveiro, Portugal
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Adelino Leite-Moreira
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Inês Falcão-Pires
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Rita Ferreira
- Department of Chemistry, Mass Spectrometry Center, QOPNA, University of Aveiro, Aveiro, Portugal
| | - Rui Vitorino
- Department of Medical Sciences, Institute of Biomedicine – iBiMED, University of Aveiro, Aveiro, Portugal
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Ghosh P, Vaidya A, Kumar A, Rangachari V. Determination of critical nucleation number for a single nucleation amyloid-β aggregation model. Math Biosci 2016; 273:70-9. [PMID: 26774039 DOI: 10.1016/j.mbs.2015.12.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/14/2015] [Indexed: 10/22/2022]
Abstract
Aggregates of amyloid-β (Aβ) peptide are known to be the key pathological agents in Alzheimer disease (AD). Aβ aggregates to form large, insoluble fibrils that deposit as senile plaques in AD brains. The process of aggregation is nucleation-dependent in which the formation of a nucleus is the rate-limiting step, and controls the physiochemical fate of the aggregates formed. Therefore, understanding the properties of nucleus and pre-nucleation events will be significant in reducing the existing knowledge-gap in AD pathogenesis. In this report, we have determined the plausible range of critical nucleation number (n(*)), the number of monomers associated within the nucleus for a homogenous aggregation model with single unique nucleation event, by two independent methods: A reduced-order stability analysis and ordinary differential equation based numerical analysis, supported by experimental biophysics. The results establish that the most likely range of n(*) is between 7 and 14 and within, this range, n(*) = 12 closely supports the experimental data. These numbers are in agreement with those previously reported, and importantly, the report establishes a new modeling framework using two independent approaches towards a convergent solution in modeling complex aggregation reactions. Our model also suggests that the formation of large protofibrils is dependent on the nature of n(*), further supporting the idea that pre-nucleation events are significant in controlling the fate of larger aggregates formed. This report has re-opened an old problem with a new perspective and holds promise towards revealing the molecular events in amyloid pathologies in the future.
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Affiliation(s)
- Preetam Ghosh
- Department of Computer Science, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Ashwin Vaidya
- Department of Mathematical Science, Montclair State University, Montclair, New Jersey, USA
| | - Amit Kumar
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi, USA ; Department of Protein Evolution, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
| | - Vijayaraghavan Rangachari
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi, USA .
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11
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Radko SP, Khmeleva SA, Suprun EV, Kozin SA, Bodoev NV, Makarov AA, Archakov AI, Shumyantseva VV. [Physico-chemical methods for studing β-amyloid aggregation]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2015; 61:203-18. [PMID: 25978387 DOI: 10.18097/pbmc20156102203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Alzheimer's disease is the most prevalent neurodegenerative pathology. According to the amyloid cascade hypothesis, a key event of the Alzheimer's disease pathogenesis is a transition of the β-amyloid peptide (Аβ) from the monomeric form to the aggregated state. The mechanism of Аβ aggregation is intensively studied in vitro, by means of synthetic peptides and various physico-chemical methods allowing evaluation of size, molecular structure, and morphology of the formed aggregates. The paper reviews both the well-known and recently introduced physico-chemical methods for analysis of Аβ aggregation, including microscopу, optical and fluorescent methods, method of electron paramagnetic resonance, electrochemical and electrophoretic methods, gel-filtration, and mass spectrometric methods. Merits and drawbacks of the methods are discussed. The unique possibility to simultaneously observe Аβ monomers as well oligomers and large aggregates by means of atomic force microscopy or fluorescence correlation spectroscopy is emphasized. The high detection sensitivity of the latter method, monitoring the aggregation process in Аβ solutions at low peptide concentrations is underlined. Among mass spectrometric methods, the ion mobility mass spectrometry is marked out as a method enabling to obtain information about both the spectrum of Аβ oligomers and their structure. It is pointed out that the use of several methods giving the complementary data about Аβ aggregates is the best experimental approach to studying the process of b-amyloid peptide aggregation in vitro.
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Affiliation(s)
- S P Radko
- Institute of Biomedical Chemistry, Moscow, Russia; Engelhardt Institute of Molecular Biology, Moscow, Russia
| | - S A Khmeleva
- Institute of Biomedical Chemistry, Moscow, Russia
| | - E V Suprun
- Institute of Biomedical Chemistry, Moscow, Russia
| | - S A Kozin
- Engelhardt Institute of Molecular Biology, Moscow, Russia
| | - N V Bodoev
- Institute of Biomedical Chemistry, Moscow, Russia
| | - A A Makarov
- Engelhardt Institute of Molecular Biology, Moscow, Russia
| | - A I Archakov
- Institute of Biomedical Chemistry, Moscow, Russia
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12
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Yi X, Feng C, Hu S, Li H, Wang J. Surface plasmon resonance biosensors for simultaneous monitoring of amyloid-beta oligomers and fibrils and screening of select modulators. Analyst 2015; 141:331-6. [PMID: 26613550 DOI: 10.1039/c5an01864a] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Oligomeric amyloid-beta (Aβ) peptides are considered as the most toxic species in Alzheimer's disease (AD). Monitoring of the Aβ aggregation profiles is critical for elucidating the oligomer toxicity and may serve as a therapeutic target for AD. By immobilizing the capture antibodies of A11 and OC that are specific to the oligomers and fibrils, respectively, in separate fluidic channels, a novel surface plasmon resonance (SPR) biosensor was designed for monitoring the oligomeric and fibrillar species of Aβ(1-42) simultaneously. The influence of curcumin, Cu(2+) and methylene blue on the amount of toxic oligomers and fibrils was evaluated. The half maximal inhibitory concentration (IC50) of curcumin and methylene blue was determined. The formation of Aβ fibrils was also validated by the thioflavin T (ThT) fluorescence assay. The results demonstrate the utility of SPR as an analytical tool for rapid and comprehensive monitoring of Aβ aggregation and screening of Aβ modulators.
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Affiliation(s)
- Xinyao Yi
- College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, P. R. China 410083.
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13
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Wang M, Li C, Lin CY. The Contributions of Segmental and Suprasegmental Information in Reading Chinese Characters Aloud. PLoS One 2015; 10:e0142060. [PMID: 26551251 PMCID: PMC4638349 DOI: 10.1371/journal.pone.0142060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 10/17/2015] [Indexed: 11/24/2022] Open
Abstract
The Chinese writing system provides an excellent case for testing the contribution of segmental and suprasegmental information in reading words aloud within the same language. In logographic Chinese characters, neither segmental nor tonal information is explicitly represented, whereas in Pinyin, an alphabetic transcription of the character, both are explicitly represented. Two primed naming experiments were conducted in which the targets were always written characters. When logographic characters served as the primes (Experiment 1), syllable segmental and tonal information appeared to be represented and encoded as an integral unit which in turn facilitated target character naming. When Pinyin served as the primes (Experiment 2), the explicit phonetic representation facilitated encoding of both segmental and suprasegmental information, but with later access to suprasegmental information. In addition, Chinese speakers were faster to name characters than Pinyin in a simple naming task (Experiment 3), suggesting that Pinyin may be read via a phonological assembly route, whereas characters may be read via a lexical route. Taken together, our findings point to the need to consider the contributions of both segmental and suprasegmental information and the time course in the well-established models for reading aloud, as well as the cognitive mechanisms underlying the reading aloud of logographic characters versus alphabetic Pinyin script.
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Affiliation(s)
- Min Wang
- Department of Human Development and Quantitative Methodology, University of Maryland, College Park, Maryland, United States of America
- * E-mail:
| | - Chuchu Li
- Department of Human Development and Quantitative Methodology, University of Maryland, College Park, Maryland, United States of America
| | - Candise Y. Lin
- Department of Psychology and Program in Hearing and Communication Neuroscience, University of Southern California, Los Angeles, California, United States of America
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14
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Radko SP, Khmeleva SA, Suprun EV, Kozin SA, Bodoev NV, Makarov AA, Archakov AI, Shumyantseva VV. Physico-chemical methods for studying amyloid-β aggregation. BIOCHEMISTRY MOSCOW-SUPPLEMENT SERIES B-BIOMEDICAL CHEMISTRY 2015. [DOI: 10.1134/s1990750815030075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Friedemann M, Helk E, Tiiman A, Zovo K, Palumaa P, Tõugu V. Effect of methionine-35 oxidation on the aggregation of amyloid-β peptide. Biochem Biophys Rep 2015; 3:94-99. [PMID: 29124171 PMCID: PMC5668694 DOI: 10.1016/j.bbrep.2015.07.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 07/22/2015] [Accepted: 07/28/2015] [Indexed: 01/12/2023] Open
Abstract
Aggregation of Aβ peptides into amyloid plaques is considered to trigger the Alzheimer’s disease (AD), however the mechanism behind the AD onset has remained elusive. It is assumed that the insoluble Aβ aggregates enhance oxidative stress (OS) by generating free radicals with the assistance of bound copper ions. The aim of our study was to establish the role of Met35 residue in the oxidation and peptide aggregation processes. Met35 can be readily oxidized by H2O2. The fibrillization of Aβ with Met35 oxidized to sulfoxide was three times slower compared to that of the regular peptide. The fibrils of regular and oxidized peptides looked similar under transmission electron microscopy. The relatively small inhibitory effect of methionine oxidation on the fibrillization suggests that the possible variation in the Met oxidation state should not affect the in vivo plaque formation. The peptide oxidation pattern was more complex when copper ions were present: addition of one oxygen atom was still the fastest process, however, it was accompanied by multiple unspecific modifications of peptide residues. Addition of copper ions to the Aβ with oxidized Met35 in the presence of H2O2, resulted a similar pattern of nonspecific modifications, suggesting that the one-electron oxidation processes in the peptide molecule do not depend on the oxidation state of Met35 residue. Thus, it can be concluded that Met35 residue is not a part of the radical generating mechanism of Aβ–Cu(II) complex. Aβ peptides with oxidized Met35 residue fibrillize three times slower than the reduced peptide. Met35 is the only residue in Aβ peptide that is oxidized by H2O2 in the absent of copper ions. In the presence of copper ions as catalyst multiple unspecific oxidative processes occur in Aβ. Previous oxidation of Met35 does not affect the unspecific oxidation in the presence of copper ions.
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Key Words
- AD, Alzheimer's disease
- Alzheimer's disease
- Aβ, Alzheimer's amyloid peptide
- Copper(II)ion
- HFIP, 1,1,1,3,3,3-hexafluoro-2-propanol
- Methionine oxidation
- OS, oxidative stress
- ROS, reactive oxygen species
- ThT, Thioflavin T
- β-amyloid
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Affiliation(s)
- Merlin Friedemann
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Eneken Helk
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Ann Tiiman
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Kairit Zovo
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Peep Palumaa
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Vello Tõugu
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
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16
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More SS, Vince R. Hyperspectral imaging signatures detect amyloidopathy in Alzheimer's mouse retina well before onset of cognitive decline. ACS Chem Neurosci 2015; 6:306-15. [PMID: 25354367 DOI: 10.1021/cn500242z] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Amyloidopathic disorders such as Alzheimer's disease present symptomology years after the entrenchment of amyloidogenic imbalance. The pathologic α-helix → β-strand conversion of amyloid β(1-42) and amyloid β(1-40) peptides causes neuronal death in the vicinity. Symptomology often presents only after significant neurodegeneration. This thus warrants early detection of amyloidopathy in Alzheimer's disease. Nonexistent modalities for direct identification and quantitation of soluble amyloid aggregates or (proto)fibrils forced us to undertake the development of a spectrophotometric technique to support ongoing drug design. Key requirements were independence from the need for extraneous staining, unambiguous amyloid aggregate detection, and minimal influence of interpretative errors. A Cytoviva instrument pivotal to this study captures scattering of light of visible-near-infrared (VNIR, 400-1000 nm) wavelengths within each pixel of the microscopic view field. We thus assembled a scattering intensity pattern database that provided "signatures" of amyloid aggregates. Comparison of unknown samples against this database enabled direct detection of amyloid aggregates. The technique was found useful for monitoring retinal and brain amyloidopathy in an ongoing preclinical anti-AD study, attesting to the technique's sensitivity and specificity. Interestingly, the technique was found applicable not just to excised brain tissue but also to isolated mouse retina. With the retina being heralded widely as a (diagnostic) extension of the CNS and retinal amyloidopathy occurring well before that in the brain, this development raises a possibility for the first direct retinal imaging diagnosis of early asymptomatic Alzheimer's disease.
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Affiliation(s)
- Swati S. More
- Center
for Drug Design, University of Minnesota, 516 Delaware Street S.E., Minneapolis, Minnesota 55455, United States
| | - Robert Vince
- Center
for Drug Design, University of Minnesota, 516 Delaware Street S.E., Minneapolis, Minnesota 55455, United States
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17
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Abstract
Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles. Nowadays mass spectrometry-based approaches play a pivotal role in both detection and characterization of proteins. Here we describe two applications to study insoluble proteins: (a) hydrogen/deuterium exchange combined with mass spectrometry to analyze structural properties of amyloid fibrils and (b) the screening for inhibitors of the aggregation process by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
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Affiliation(s)
- Sílvia Bronsoms
- Servei de Proteòmica i Biologia Estructural, Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), 08193, Barcelona, Spain,
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18
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Sun S, Kennedy RT. Droplet electrospray ionization mass spectrometry for high throughput screening for enzyme inhibitors. Anal Chem 2014; 86:9309-14. [PMID: 25137241 PMCID: PMC4165461 DOI: 10.1021/ac502542z] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 08/19/2014] [Indexed: 12/20/2022]
Abstract
High throughput screening (HTS) is important for identifying molecules with desired properties. Mass spectrometry (MS) is potentially powerful for label-free HTS due to its high sensitivity, speed, and resolution. Segmented flow, where samples are manipulated as droplets separated by an immiscible fluid, is an intriguing format for high throughput MS because it can be used to reliably and precisely manipulate nanoliter volumes and can be directly coupled to electrospray ionization (ESI) MS for rapid analysis. In this study, we describe a "MS Plate Reader" that couples standard multiwell plate HTS workflow to droplet ESI-MS. The MS plate reader can reformat 3072 samples from eight 384-well plates into nanoliter droplets segmented by an immiscible oil at 4.5 samples/s and sequentially analyze them by MS at 2 samples/s. Using the system, a label-free screen for cathepsin B modulators against 1280 chemicals was completed in 45 min with a high Z-factor (>0.72) and no false positives (24 of 24 hits confirmed). The assay revealed 11 structures not previously linked to cathepsin inhibition. For even larger scale screening, reformatting and analysis could be conducted simultaneously, which would enable more than 145,000 samples to be analyzed in 1 day.
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Affiliation(s)
- Shuwen Sun
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Robert T. Kennedy
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department
of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
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19
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Veloso AJ, Chow AM, Ganesh HVS, Li N, Dhar D, Wu DCH, Mikhaylichenko S, Brown IR, Kerman K. Electrochemical Immunosensors for Effective Evaluation of Amyloid-Beta Modulators on Oligomeric and Fibrillar Aggregation Processes. Anal Chem 2014; 86:4901-9. [DOI: 10.1021/ac500424t] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
| | - Ari M. Chow
- Centre
for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Hashwin V. S. Ganesh
- Centre
for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Nan Li
- Department
of Physical and Environmental Sciences and
| | - Devjani Dhar
- Department
of Physical and Environmental Sciences and
| | | | | | - Ian R. Brown
- Centre
for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Kagan Kerman
- Department
of Physical and Environmental Sciences and
- Centre
for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
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20
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Stoilova T, Colombo L, Forloni G, Tagliavini F, Salmona M. A new face for old antibiotics: tetracyclines in treatment of amyloidoses. J Med Chem 2013; 56:5987-6006. [PMID: 23611039 DOI: 10.1021/jm400161p] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The use of tetracyclines has declined because of the appearance of resistant bacterial strains. However, the indications of nonantimicrobial activities of these drugs have considerably raised interest and triggered clinical trials for a number of different pathologies. About 10 years ago we first reported that tetracyclines inhibited the aggregation of prion protein fragments and Alzheimer's β peptides, destabilizing their aggregates and promoting their degradation by proteases. On the basis of these observations, the antiamyloidogenic effects of tetracyclines on a variety of amyloidogenic proteins were studied and confirmed by independent research groups. In this review we comment on the data available on their antiamyloidogenic activity in preclinical and clinical studies. We also put forward that the beneficial effects of these drugs are a result of a peculiar pleiotropic action, comprising their interaction with oligomers and disruption of fibrils, as well as their antioxidant, anti-inflammatory, antiapoptotic, and matrix metalloproteinase inhibitory activities.
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Affiliation(s)
- Tatiana Stoilova
- IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Via Giuseppe La Masa 19, 20156 Milano, Italy
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21
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Tiiman A, Noormägi A, Friedemann M, Krishtal J, Palumaa P, Tõugu V. Effect of agitation on the peptide fibrillization: Alzheimer's amyloid-β peptide 1-42 but not amylin and insulin fibrils can grow under quiescent conditions. J Pept Sci 2013; 19:386-91. [PMID: 23609985 DOI: 10.1002/psc.2513] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 03/11/2013] [Indexed: 11/08/2022]
Abstract
Many peptides and proteins can form fibrillar aggregates in vitro, but only a limited number of them are forming pathological amyloid structures in vivo. We studied the fibrillization of four peptides--Alzheimer's amyloid-β (Aβ) 1-40 and 1-42, amylin and insulin. In all cases, intensive mechanical agitation of the solution initiated fast fibrillization. However, when the mixing was stopped during the fibril growth phase, the fibrillization of amylin and insulin was practically stopped, and the rate for Aβ40 substantially decreased, whereas the fibrillization of Aβ42 peptide continued to proceed with almost the same rate as in the agitated conditions. The reason for the different sensitivity of the in vitro fibrillization of these peptides towards agitation in the fibril growth phase remains elusive.
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Affiliation(s)
- Ann Tiiman
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, Tallinn, 12618, Estonia.
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22
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Chan FTS, Kaminski Schierle GS, Kumita JR, Bertoncini CW, Dobson CM, Kaminski CF. Protein amyloids develop an intrinsic fluorescence signature during aggregation. Analyst 2013; 138:2156-62. [PMID: 23420088 PMCID: PMC5360231 DOI: 10.1039/c3an36798c] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report observations of an intrinsic fluorescence in the visible range, which develops during the aggregation of a range of polypeptides, including the disease-related human peptides amyloid-β(1-40) and (1-42), lysozyme and tau. Characteristic fluorescence properties such as the emission lifetime and spectra were determined experimentally. This intrinsic fluorescence is independent of the presence of aromatic side-chain residues within the polypeptide structure. Rather, it appears to result from electronic levels that become available when the polypeptide chain folds into a cross-β sheet scaffold similar to what has been reported to take place in crystals. We use these findings to quantify protein aggregation in vitro by fluorescence imaging in a label-free manner.
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Affiliation(s)
- Fiona T. S. Chan
- Department of Chemical Engineering and Biotechnology, University of
Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA, UK
| | - Gabriele S. Kaminski Schierle
- Department of Chemical Engineering and Biotechnology, University of
Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA, UK
| | - Janet R. Kumita
- Department of Chemistry, University of Cambridge, Lensfield Road,
Cambridge CB2 1EW, UK
| | - Carlos W. Bertoncini
- Institute for Research in Biomedicine, Baldiri Reixac 10, 08028,
Barcelona, Spain
| | - Christopher M. Dobson
- Department of Chemistry, University of Cambridge, Lensfield Road,
Cambridge CB2 1EW, UK
| | - Clemens F. Kaminski
- Department of Chemical Engineering and Biotechnology, University of
Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA, UK
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23
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Jameson LP, Dzyuba SV. Aza-BODIPY: improved synthesis and interaction with soluble Aβ1-42 oligomers. Bioorg Med Chem Lett 2013; 23:1732-5. [PMID: 23416005 PMCID: PMC3662365 DOI: 10.1016/j.bmcl.2013.01.065] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 01/07/2013] [Accepted: 01/16/2013] [Indexed: 01/26/2023]
Abstract
Dye-binding assays that are used to evaluate anti-aggregation ability of small molecule inhibitors towards amyloids are known to be prone to false-positive effects due to spectral overlaps between the dye and the inhibitor. Aza-BODIPY dye, which has both excitation and emission maxima above 600nm, exhibits a significant increase in its fluorescence intensity in the presence of soluble oligomers of Aβ1-42. These results indicate that aza-BODIPY could serve as a near-IR probe for detecting conformational changes of Aβ1-42 soluble oligomers in vitro, and it should eliminate false-positive effects that are associated with currently utilized thioflavin T-based dyes. In addition, a facile synthesis of aza-BODIPY has been developed, which might further expand the applications of this dye.
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Affiliation(s)
- Laramie P. Jameson
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76129, USA
| | - Sergei V. Dzyuba
- Department of Chemistry, Texas Christian University, Fort Worth, TX 76129, USA
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24
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Jameson LP, Smith NW, Dzyuba SV. Dye-binding assays for evaluation of the effects of small molecule inhibitors on amyloid (aβ) self-assembly. ACS Chem Neurosci 2012; 3:807-19. [PMID: 23173064 DOI: 10.1021/cn300076x] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 08/06/2012] [Indexed: 01/07/2023] Open
Abstract
Dye-binding assays, such as those utilizing Congo red and thioflavin T, are among the most widely used tools to probe the aggregation of amyloidogenic biomolecules and for the evaluation of small molecule inhibitors of amyloid aggregation and fibrillization. A number of recent reports have indicated that these dye-binding assays could be prone to false positive effects when assessing inhibitors' potential toward Aβ peptides, species involved in Alzheimer's disease. Specifically, this review focuses on the application of thioflavin T for determining the efficiency of small molecule inhibitors of Aβ aggregation and addresses potential reasons that might be associated with the false positive effects in an effort to increase reliability of dye-binding assays.
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Affiliation(s)
- Laramie P. Jameson
- Department of Chemistry, Texas Christian University, Fort Worth, Texas 76129, United States
| | - Nicholas W. Smith
- Department of Chemistry, Texas Christian University, Fort Worth, Texas 76129, United States
| | - Sergei V. Dzyuba
- Department of Chemistry, Texas Christian University, Fort Worth, Texas 76129, United States
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25
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Noormägi A, Primar K, Tõugu V, Palumaa P. Interference of low-molecular substances with the thioflavin-T fluorescence assay of amyloid fibrils. J Pept Sci 2011; 18:59-64. [PMID: 22083646 DOI: 10.1002/psc.1416] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 08/11/2011] [Accepted: 08/18/2011] [Indexed: 12/31/2022]
Abstract
Abnormal fibrillization of amyloidogenic peptides/proteins has been linked to various neurodegenerative diseases such as Alzheimer's and Parkinson's disease as well as with type-II diabetes mellitus. The kinetics of protein fibrillization is commonly studied by using a fluorescent dye Thioflavin T (ThT) that binds to protein fibrils and exerts increased fluorescence intensity in bound state. Recently, it has been demonstrated that several low-molecular weight compounds like Basic Blue 41, Basic Blue 12, Azure C, and Tannic acid interfere with the fluorescence of ThT bound to Alzheimers' amyloid-β fibrils and cause false positive results during the screening of fibrillization inhibitors. In the current study, we demonstrated that the same selected substances also decrease the fluorescence signal of ThT bound to insulin fibrils already at submicromolar or micromolar concentrations. Kinetic experiments show that unlike to true inhibitors, these compounds did neither decrease the fibrillization rate nor increase the lag-period. Absence of soluble insulin in the end of the experiment confirmed that these compounds do not disaggregate the insulin fibrils and, thus, are not fibrillization inhibitors at concentrations studied. Our results show that interference with ThT test is a general phenomenon and more attention has to be paid to interpretation of kinetic results of protein fibrillization obtained by using fluorescent dyes.
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Affiliation(s)
- Andra Noormägi
- Department of Gene Technology, Tallinn University of Technology, Akadeemia 15, 12618, Tallinn, Estonia
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26
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Tõugu V, Tiiman A, Palumaa P. Interactions of Zn(ii) and Cu(ii) ions with Alzheimer's amyloid-beta peptide. Metal ion binding, contribution to fibrillization and toxicity. Metallomics 2011; 3:250-61. [DOI: 10.1039/c0mt00073f] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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