1
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Siposova K, Huntosova V, Sedlakova D, Macajova M, Bilcik B, Nair AV, Nair S, Hovhannisyan V, Chen SJ, Musatov A. Biocompatible zeolite-dye composites with anti-amyloidogenic properties. Int J Biol Macromol 2023; 251:126331. [PMID: 37579899 DOI: 10.1016/j.ijbiomac.2023.126331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 08/07/2023] [Accepted: 08/11/2023] [Indexed: 08/16/2023]
Abstract
One of the most attractive approaches in biomedicine and pharmacy is the application of multifunctional materials. The mesoporous structure of clinoptilolite (CZ) absorbs various types of substances and can be used as a model for studying the carriers for targeted drug delivery with controlled release. CZ-dye composites are fabricated by incorporation into clinoptilolite pores commonly used dyes, aluminum phthalocyanine, zinc porphine, and hypericin. We examined and compared the effect of pure dyes and CZ-dye composites on insulin amyloidogenesis. The formation of insulin amyloid fibrils and the disassembly of preformed fibrils is significantly affected by any of the three compounds, however, the strongest effect is observed for aluminum phthalocyanine indicating a structurally-dependent anti-amyloidogenic activity of the dyes. The incorporation of dyes into CZ particles resulted in enhanced anti-amyloidogenic activity in comparison to pure CZ particles. The cell metabolic activity, biocompatibility and fluorescence biodistribution of the dyes entrapped in the composites were tested in vitro (U87 MG cells) and in vivo in the quail chorioallantoic membrane model. Considering the photoactive properties of the dyes used, we assume their applicability in photodiagnostics and photodynamic therapy. It can also be expected that their anti-amyloidogenic potential can be enhanced by photodynamic effect.
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Affiliation(s)
- Katarina Siposova
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 04001, Kosice, Slovakia; College of Photonics, National Yang Ming Chiao Tung University, Tainan 711, Taiwan.
| | - Veronika Huntosova
- Center for Interdisciplinary Biosciences, Technology, and Innovation Park, P.J. Safarik University in Kosice, Jesenna 5, 041 54, Kosice, Slovakia.
| | - Dagmar Sedlakova
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 04001, Kosice, Slovakia.
| | - Mariana Macajova
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Dubravska cesta 9, 840 05 Bratislava, Slovakia.
| | - Boris Bilcik
- Institute of Animal Biochemistry and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Dubravska cesta 9, 840 05 Bratislava, Slovakia.
| | | | - Sumesh Nair
- College of Photonics, National Yang Ming Chiao Tung University, Tainan 711, Taiwan
| | | | - Shean-Jen Chen
- College of Photonics, National Yang Ming Chiao Tung University, Tainan 711, Taiwan.
| | - Andrey Musatov
- Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 04001, Kosice, Slovakia.
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2
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Siposova K, Sedlakova D, Musatov A. Monitoring the surface tension by the pendant drop technique for detection of insulin fibrillogenesis. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:4174-4178. [PMID: 34523621 DOI: 10.1039/d1ay01126j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Monitoring the aggregation of amyloid-prone proteins is critical for understanding the mechanism of amyloid fibril formation. Insulin, when dissolved in low pH buffer, has a surface tension of 61-64 mN m-1, as measured by the pendant drop technique. Formation of insulin amyloid fibrils resulted in the increase of the surface tension values up to 71.2-73.5 mN m-1. The kinetics of fibril formation and fibril morphology were validated by ThT fluorescence and AFM, respectively. The results demonstrate that monitoring the surface tension by the pendant drop technique is a valuable tool for the detection of insulin amyloid aggregation.
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Affiliation(s)
- Katarina Siposova
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, Kosice, 040 01, Slovakia.
| | - Dagmar Sedlakova
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, Kosice, 040 01, Slovakia.
| | - Andrey Musatov
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, Kosice, 040 01, Slovakia.
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3
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Jesus CSH, Soares HT, Piedade AP, Cortes L, Serpa C. Using amyloid autofluorescence as a biomarker for lysozyme aggregation inhibition. Analyst 2021; 146:2383-2391. [PMID: 33646214 DOI: 10.1039/d0an02260h] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The assembly of proteins into amyloidogenic aggregates underlies the onset and symptoms of several pathologies, including Alzheimer's disease, Parkinson's disease and type II diabetes. Among the efforts for fighting these diseases, there is a great demand for developing novel, fast and reliable methods for in vitro screening of new drugs that may suppress or reverse amyloidogenesis. Recent studies unravelled a progressive increase in a blue autofluorescence upon amyloid formation originated from many different proteins, including the peptide amyloid-β, lysozyme or insulin. Herein, we propose a drug screening method using this property, avoiding the use of external probe dyes. We demonstrate that the inhibition of lysozyme amyloid formation by means of two known inhibitors, tartrazine and amaranth, can be monitored based on the autofluorescence of lysozyme amyloid aggregates. Our results show that amyloid luminescence is an intrinsic property that can be potentially applied in a screening assay, allowing the ranking of drug efficiency. The assays demonstrated here are fast to perform and suitable for scaling using microplate assays, configuring a new sensitive and economically feasible method.
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Affiliation(s)
- Catarina S H Jesus
- University of Coimbra, CQC, Department of Chemistry, 3004-535 Coimbra, Portugal.
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4
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Huyst AM, Deleu LJ, Luyckx T, Lambrecht MA, Van Camp J, Delcour JA, Van der Meeren P. Influence of hydrophobic interfaces and shear on ovalbumin amyloid-like fibril formation in oil-in-water emulsions. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2020.106327] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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5
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The effect of three polyphenols and some other antioxidant substances on amyloid fibril formation by Human cystatin C. Neurochem Int 2020; 140:104806. [DOI: 10.1016/j.neuint.2020.104806] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/26/2020] [Accepted: 07/07/2020] [Indexed: 01/24/2023]
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6
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Soeda Y, Saito M, Maeda S, Ishida K, Nakamura A, Kojima S, Takashima A. Methylene Blue Inhibits Formation of Tau Fibrils but not of Granular Tau Oligomers: A Plausible Key to Understanding Failure of a Clinical Trial for Alzheimer's Disease. J Alzheimers Dis 2020; 68:1677-1686. [PMID: 30909223 DOI: 10.3233/jad-181001] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease pathology is characterized by extracellular deposits of amyloid-β (Aβ) and intracellular inclusions of hyperphosphorylated tau. Although genetic studies of familial Alzheimer's disease suggest a causal link between Aβ and disease symptoms, the failure of various Aβ-targeted strategies to slow or halt disease progression has led to consideration of the idea that inhibition of tau aggregation might be a more promising therapeutic approach. Methylene blue (MB), which inhibits tau aggregation and rescue memory deficits in a mouse model of tauopathy, however, lacked efficacy in a recent Phase III clinical trial. In order to gain insight into this failure, the present study was designed to examine the mechanism through which MB inhibits tau aggregation. We found that MB inhibits heparin-induced tau aggregation in vitro, as measured by thioflavin T fluorescence. Further, MB reduced the amount of tau in precipitants recovered after ultracentrifugation of the aggregation mixture. Atomic force microscopy revealed that MB reduces the number of tau fibrils but increases the number of granular tau oligomers. The latter result was confirmed by sucrose gradient centrifugation: MB treatment was associated with higher levels of granular tau oligomers (fraction 3) and lower levels of tau fibrils (fractions 5 and 6). We previously demonstrated that the formation of granular tau oligomers, rather than tau fibrils, is essential for neuronal death. Thus, the fact that MB actions are limited to inhibition of tau fibril formation provides a mechanistic explanation for the poor performance of MB in the recent Phase III clinical trial.
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Affiliation(s)
- Yoshiyuki Soeda
- Department of Alzheimer's Disease, Faculty of Life Science, Gakushuin University, Toshima-ku, Tokyo, Japan
| | - Marino Saito
- Department of Alzheimer's Disease, Faculty of Life Science, Gakushuin University, Toshima-ku, Tokyo, Japan
| | - Sumihiro Maeda
- Department of Physiology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Kohki Ishida
- Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo, Japan
| | - Akira Nakamura
- Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo, Japan
| | - Shuichi Kojima
- Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo, Japan
| | - Akihiko Takashima
- Department of Alzheimer's Disease, Faculty of Life Science, Gakushuin University, Toshima-ku, Tokyo, Japan
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7
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Witter S, Samoson A, Vilu R, Witter R. Screening of Nutraceuticals and Plant Extracts for Inhibition of Amyloid-β Fibrillation. J Alzheimers Dis 2020; 73:1003-1012. [DOI: 10.3233/jad-190758] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Steffi Witter
- School of Information Technologies, Department of Health Technologies, Tallinn University of Technology, Tallinn, Estonia
- School of Science, Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Ago Samoson
- School of Information Technologies, Department of Health Technologies, Tallinn University of Technology, Tallinn, Estonia
| | - Raivo Vilu
- Competence Center of Food and Fermentation Technology (TFTAK), Tallinn, Estonia
| | - Raiker Witter
- Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology, Eggenstein-Leopoldshafen, Germany
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8
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Witter S, Witter R, Vilu R, Samoson A. Medical Plants and Nutraceuticals for Amyloid-β Fibrillation Inhibition. J Alzheimers Dis Rep 2018; 2:239-252. [PMID: 30599045 PMCID: PMC6311354 DOI: 10.3233/adr-180066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2018] [Indexed: 11/30/2022] Open
Abstract
Plaque formation due to amyloid-β oligomerization and fibrillation is a key issue for its deposition in the brains of dementia and Alzheimer's disease patients. Related drugs preventing this peptide fibril accumulation bear the potential of considerable medical and social value. In this study, we performed in vitro fibrillation inhibition tests with eight different medical plant extracts and nutraceuticals using fluorescence spectroscopy. Successful inhibition of the following plant extracts and nutraceuticals were obtained: Withania somnifera, Centella asiatica, Bacopa monnieri, and Convolvulus pluricaulis, providing new drug candidates for the prevention and treatment of Alzheimer's disease.
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Affiliation(s)
- Steffi Witter
- Department of Health Technologies, School of Information Technologies, Tallinn University of Technology, Tallinn, Estonia
| | - Raiker Witter
- Department of Health Technologies, School of Information Technologies, Tallinn University of Technology, Tallinn, Estonia
- Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology, Eggenstein-Leopoldshafen, Germany
| | - Raivo Vilu
- Competence Center of Food and Fermentation Technology (TFTAK), Tallinn, Estonia
| | - Ago Samoson
- Department of Health Technologies, School of Information Technologies, Tallinn University of Technology, Tallinn, Estonia
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9
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Wang T, Zhang L, Wang J, Feng Y, Xu E, Mao X, Liu L. Evaluation of the photo-degradation of Alzheimer's amyloid fibrils with a label-free approach. Chem Commun (Camb) 2018; 54:13084-13087. [PMID: 30394470 PMCID: PMC6404227 DOI: 10.1039/c8cc07164k] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Degradation of amyloid-β (Aβ) aggregates has been considered as an attractive therapeutic and preventive strategy against Alzheimer's disease (AD). However, an in situ, real-time, and label-free technique is still lacking to understand the degradation process of Aβ aggregates. In this work, we developed a novel method to quantitatively evaluate the degradation of Aβ fibrils by photoactive meso-tetra(4-sulfonatophenyl)porphyrin under UV irradiation with quartz crystal microbalance (QCM).
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Affiliation(s)
- Tianke Wang
- Institute for Advanced Materials, Jiangsu University, China.
| | - Liwei Zhang
- Institute for Advanced Materials, Jiangsu University, China.
| | - Jie Wang
- Institute for Advanced Materials, Jiangsu University, China.
| | - Yonghai Feng
- Institute for Advanced Materials, Jiangsu University, China.
| | - Enquan Xu
- Institute for Cell Engineering, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore,
| | - Xiaobo Mao
- Institute for Cell Engineering, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore,
| | - Lei Liu
- Institute for Advanced Materials, Jiangsu University, China.
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10
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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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11
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Wang J, Liu L, Ge D, Zhang H, Feng Y, Zhang Y, Chen M, Dong M. Differential Modulating Effect of MoS 2 on Amyloid Peptide Assemblies. Chemistry 2018; 24:3397-3402. [PMID: 29210123 DOI: 10.1002/chem.201704593] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Indexed: 11/11/2022]
Abstract
The abnormal fibrillogenesis of amyloid peptides such as amyloid fibril and senior amyloid plaques, is associated with the pathogenesis of many amyloid diseases. Hence, modulation of amyloid assemblies is related to the possible pathogenesis of some diseases. Some two-dimensional nanomaterials, that is, graphene oxide, tungsten disulfide, exhibit strong modulation effects on the amyloid fibrillogenesis. Herein, the modulation effect of molybdenum disulfide on two amyloid peptide assemblies based on the label-free techniques is presented, including quartz crystal microbalance (QCM), AFM, and CD spectroscopy. MoS2 presents different modulating effects on the assembly of amyloid-β peptide (33-42) [Aβ (33-42)] and amylin (20-29), mainly owing to the distinct affinity between amyloid peptides and MoS2 . This is to our knowledge the first report of MoS2 as a modulator for amyloid aggregation. It enriches the variety of 2D nanomodulators of amyloid fibrillogenesis and explains the mechanism for the self-assembly of amyloid peptides, and expands the applications of MoS2 in biology.
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Affiliation(s)
- Jie Wang
- Institute for Advanced Materials, Jiangsu University, 212013 Xuefu Road No. 301, Zhenjiang city, Jinagsu Province, P.R. China.,Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000, Aarhus C, Denmark
| | - Lei Liu
- Institute for Advanced Materials, Jiangsu University, 212013 Xuefu Road No. 301, Zhenjiang city, Jinagsu Province, P.R. China
| | - Daohan Ge
- School of Mechanical Engineering, Micro/nano Science and Technology Center, Jiangsu University, 212013 Xuefu Road No. 301, Zhenjiang city, Jinagsu Province, P.R. China
| | - Hongxing Zhang
- Institute for Advanced Materials, Jiangsu University, 212013 Xuefu Road No. 301, Zhenjiang city, Jinagsu Province, P.R. China
| | - Yonghai Feng
- Institute for Advanced Materials, Jiangsu University, 212013 Xuefu Road No. 301, Zhenjiang city, Jinagsu Province, P.R. China
| | - Yibang Zhang
- Zhang Department of Pharmaceutics, School of Pharmacy, Jiangsu University, 212013 Xuefu Road No. 301, Zhenjiang city, Jinagsu Province, P.R. China
| | - Menglin Chen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000, Aarhus C, Denmark
| | - Mingdong Dong
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, 8000, Aarhus C, Denmark
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12
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13
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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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14
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Anti-Prion Screening for Acridine, Dextran, and Tannic Acid using Real Time-Quaking Induced Conversion: A Comparison with PrPSc-Infected Cell Screening. PLoS One 2017; 12:e0170266. [PMID: 28095474 PMCID: PMC5240994 DOI: 10.1371/journal.pone.0170266] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 12/30/2016] [Indexed: 11/19/2022] Open
Abstract
Prion propagation is mediated by the structural alteration of normal prion protein (PrPC) to generate pathogenic prion protein (PrPSc). To date, compounds for the inhibition of prion propagation have mainly been screened using PrPSc-infected cells. Real time-quaking-induced conversion (RT-QuIC) is one alternative screening method. In this study, we assessed the propagation inhibition effects of known anti-prion compounds using RT-QuIC and compared the results with those from a PrPSc-infected cell assay. Compounds were applied to RT-QuIC reactions at 0 h or 22 h after prion propagation to determine whether they inhibited propagation or reduced amplified aggregates. RT-QuIC reactions in presence of acridine, dextran sulfate sodium (DSS), and tannic acid inhibited seeded aggregation with sporadic Creutzfeldt-Jakob disease at 0 h. After treatment at 22 h, amplified fluorescence was decreased in wells treated with either acridine or tannic acid. Compound activities were verified by western blot of RT-QuIC products and in a dye-independent conversion assay, the Multimer Detection System. Protease K-resistant PrPSc fragments (PrPres) were reduced by DSS and tannic acid in the PrPSc-infected cell assay. Importantly, these inhibitory effects were similar despite different treatment times (0 h versus 3 days). Consequentially, RT-QuIC enabled the more specific classification of compounds according to action (i.e., inhibition of prion propagation versus reduction of amplified aggregates). RT-QuIC addresses the limitations of cell-based screening methods and can be used to further aid our understanding of the mechanisms of action of anti-prion compounds.
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15
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Schlein M. Insulin Formulation Characterization-the Thioflavin T Assays. AAPS JOURNAL 2016; 19:397-408. [PMID: 28000098 DOI: 10.1208/s12248-016-0028-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/08/2016] [Indexed: 11/30/2022]
Abstract
The insulin molecule was discovered in 1921. Shortly thereafter, its propensity towards amyloid fibril formation, fibrillation, was observed and described in the literature as a "precipitate." In the past decades, the increased incidence of type 2 diabetes has reached global epidemic proportions. This has emphasized the demands for both insulin production and the development of modern insulin products for unmet medical needs. Bringing such new insulin drug products to the market for the benefit of patients requires that many CMC-related processes are understood, described, and controlled. One potential undesired process is insulin fibril formation. The compound thioflavin T (ThT) is known as a fluorescent probe for amyloid fibrils. As such, ThT is utilized in a versatile research assay in microtiter plate format, the ThT assay. This review will describe an experimental set-up using not only a ThT microtiter plate assay but also two orthogonal methods. The use of the ThT assay in research and characterization of insulin analogues, as well as formulations of insulin, is described by cases drawn from the scientific literature and patents. The ThT assay is compared to other physical stability tests and in conclusion the advantages and limitations of the assay are compared.
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Affiliation(s)
- Morten Schlein
- Injectable Formulation Research, Global Research, Novo Nordisk A/S, Novo Nordisk Park H6.S.09.1, DK2760, Maaloev, Denmark.
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16
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Porter T, Bharadwaj P, Groth D, Paxman A, Laws SM, Martins RN, Verdile G. The Effects of Latrepirdine on Amyloid-β Aggregation and Toxicity. J Alzheimers Dis 2016; 50:895-905. [PMID: 26836170 PMCID: PMC4927897 DOI: 10.3233/jad-150790] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Latrepirdine (Dimebon) has been demonstrated to be a neuroprotective and cognition improving agent in neurodegenerative diseases that feature protein aggregation and deposition, such as Alzheimer's disease (AD). The accumulation of amyloid-β (Aβ) protein aggregates is a key event in the neurodegenerative process in AD. This study explores if latrepirdine modulation of protein aggregation contributes to its neuroprotective mechanism of action. Assessment of neuronal cell death showed that there was a significant reduction in lactate dehydrogenase release at an equimolar ratio of Aβ:latrepirdine and with lower concentrations of latrepirdine. The ability of latrepirdine to alter the formation of Aβ42 aggregates was assessed by thioflavin-T fluorescence, western immunoblotting and atomic force microscopy (AFM). Despite showing a reduction in thioflavin-T fluorescence with latrepirdine treatment, indicating a decrease in aggregation, immunoblotting and AFM showed a modest increase in both the formation and size of Aβ aggregates. The discrepancies between thioflavin-T and the other assays are consistent with previous evidence that cyclic molecules can interfere with thioflavin-T binding of amyloid protein preparations. The ability of latrepirdine to modulate Aβ aggregation appears to be independent of its neuroprotective effects, and is unlikely to be a mechanism by which latrepirdine offers protection. This study investigates the effect of latrepirdine on Aβ aggregation, and presents evidence suggesting that caution should be applied in the use of thioflavin-T fluorescence based assays as a method for screening compounds for protein aggregation altering properties.
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Affiliation(s)
- Tenielle Porter
- School of Biomedical Sciences, CHIRI Biosciences Research Precinct, Faculty of Health Sciences, Curtin University, Western Australia, Australia.,Centre of Excellence for Alzheimer's Disease Research and Care, School of Medical Sciences, Edith Cowan University, Western Australia, Australia
| | - Prashant Bharadwaj
- School of Biomedical Sciences, CHIRI Biosciences Research Precinct, Faculty of Health Sciences, Curtin University, Western Australia, Australia.,Centre of Excellence for Alzheimer's Disease Research and Care, School of Medical Sciences, Edith Cowan University, Western Australia, Australia
| | - David Groth
- School of Biomedical Sciences, CHIRI Biosciences Research Precinct, Faculty of Health Sciences, Curtin University, Western Australia, Australia.,School of Psychiatry and Clinical Neuroscience, University of Western Australia, Western Australia, Australia
| | - Adrian Paxman
- School of Biomedical Sciences, CHIRI Biosciences Research Precinct, Faculty of Health Sciences, Curtin University, Western Australia, Australia
| | - Simon M Laws
- Centre of Excellence for Alzheimer's Disease Research and Care, School of Medical Sciences, Edith Cowan University, Western Australia, Australia
| | - Ralph N Martins
- Centre of Excellence for Alzheimer's Disease Research and Care, School of Medical Sciences, Edith Cowan University, Western Australia, Australia.,School of Psychiatry and Clinical Neuroscience, University of Western Australia, Western Australia, Australia.,The Sir James McCusker Alzheimer's Disease Research Unit, Hollywood Private Hospital, Western Australia, Australia
| | - Giuseppe Verdile
- School of Biomedical Sciences, CHIRI Biosciences Research Precinct, Faculty of Health Sciences, Curtin University, Western Australia, Australia.,Centre of Excellence for Alzheimer's Disease Research and Care, School of Medical Sciences, Edith Cowan University, Western Australia, Australia.,School of Psychiatry and Clinical Neuroscience, University of Western Australia, Western Australia, Australia.,The Sir James McCusker Alzheimer's Disease Research Unit, Hollywood Private Hospital, Western Australia, Australia
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17
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EPPS rescues hippocampus-dependent cognitive deficits in APP/PS1 mice by disaggregation of amyloid-β oligomers and plaques. Nat Commun 2015; 6:8997. [PMID: 26646366 PMCID: PMC4686862 DOI: 10.1038/ncomms9997] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 10/23/2015] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by the transition of amyloid-β (Aβ) monomers into toxic oligomers and plaques. Given that Aβ abnormality typically precedes the development of clinical symptoms, an agent capable of disaggregating existing Aβ aggregates may be advantageous. Here we report that a small molecule, 4-(2-hydroxyethyl)-1-piperazinepropanesulphonic acid (EPPS), binds to Aβ aggregates and converts them into monomers. The oral administration of EPPS substantially reduces hippocampus-dependent behavioural deficits, brain Aβ oligomer and plaque deposits, glial γ-aminobutyric acid (GABA) release and brain inflammation in an Aβ-overexpressing, APP/PS1 transgenic mouse model when initiated after the development of severe AD-like phenotypes. The ability of EPPS to rescue Aβ aggregation and behavioural deficits provides strong support for the view that the accumulation of Aβ is an important mechanism underlying AD. Amyloid-beta deposits are a pathological hallmark of Alzheimer's disease, and have previously been targeted in immunisation therapies. Here, the authors show that oral administration of the small molecule EPPS reduces Aß plaque and oligomer load in APP/PS1 mice and improves learning and memory performance.
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18
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Šneideris T, Baranauskienė L, Cannon JG, Rutkienė R, Meškys R, Smirnovas V. Looking for a generic inhibitor of amyloid-like fibril formation among flavone derivatives. PeerJ 2015; 3:e1271. [PMID: 26421240 PMCID: PMC4586895 DOI: 10.7717/peerj.1271] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 09/04/2015] [Indexed: 01/08/2023] Open
Abstract
A range of diseases is associated with amyloid fibril formation. Despite different proteins being responsible for each disease, all of them share similar features including beta-sheet-rich secondary structure and fibril-like protein aggregates. A number of proteins can form amyloid-like fibrils in vitro, resembling structural features of disease-related amyloids. Given these generic structural properties of amyloid and amyloid-like fibrils, generic inhibitors of fibril formation would be of interest for treatment of amyloid diseases. Recently, we identified five outstanding inhibitors of insulin amyloid-like fibril formation among the pool of 265 commercially available flavone derivatives. Here we report testing of these five compounds and of epi-gallocatechine-3-gallate (EGCG) on aggregation of alpha-synuclein and beta-amyloid. We used a Thioflavin T (ThT) fluorescence assay, relying on halftimes of aggregation as the measure of inhibition. This method avoids large numbers of false positive results. Our data indicate that four of the five flavones and EGCG inhibit alpha-synuclein aggregation in a concentration-dependent manner. However none of these derivatives were able to increase halftimes of aggregation of beta-amyloid.
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Affiliation(s)
- Tomas Šneideris
- Department of Biothermodynamics and Drug Design, Vilnius University Institute of Biotechnology , Vilnius , Lithuania
| | - Lina Baranauskienė
- Department of Biothermodynamics and Drug Design, Vilnius University Institute of Biotechnology , Vilnius , Lithuania
| | - Jonathan G Cannon
- Department of Natural Sciences and Engineering, Middle Georgia State University , Cochran, GA , USA
| | - Rasa Rutkienė
- Department of Molecular Microbiology and Biotechnology, Vilnius University Institute of Biochemistry , Vilnius , Lithuania
| | - Rolandas Meškys
- Department of Molecular Microbiology and Biotechnology, Vilnius University Institute of Biochemistry , Vilnius , Lithuania
| | - Vytautas Smirnovas
- Department of Biothermodynamics and Drug Design, Vilnius University Institute of Biotechnology , Vilnius , Lithuania
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19
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Nasir I, Linse S, Cabaleiro-Lago C. Fluorescent filter-trap assay for amyloid fibril formation kinetics in complex solutions. ACS Chem Neurosci 2015; 6:1436-44. [PMID: 25946560 PMCID: PMC4599436 DOI: 10.1021/acschemneuro.5b00104] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Indexed: 12/15/2022] Open
Abstract
Amyloid fibrils are the most distinct components of the plaques associated with various neurodegenerative diseases. Kinetic studies of amyloid fibril formation shed light on the microscopic mechanisms that underlie this process as well as the contributions of internal and external factors to the interplay between different mechanistic steps. Thioflavin T is a widely used noncovalent fluorescent probe for monitoring amyloid fibril formation; however, it may suffer from limitations due to the unspecific interactions between the dye and the additives. Here, we present the results of a filter-trap assay combined with the detection of fluorescently labeled amyloid β (Aβ) peptide. The filter-trap assay separates formed aggregates based on size, and the fluorescent label attached to Aβ allows for their detection. The times of half completion of the process (t1/2) obtained by the filter-trap assay are comparable to values from the ThT assay. High concentrations of human serum albumin (HSA) and carboxyl-modified polystyrene nanoparticles lead to an elevated ThT signal, masking a possible fibril formation event. The filter-trap assay allows fibril formation to be studied in the presence of those substances and shows that Aβ fibril formation is kinetically inhibited by HSA and that the amount of fibrils formed are reduced. In contrast, nanoparticles exhibit a dual-behavior governed by their concentration.
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Affiliation(s)
- Irem Nasir
- Department of Biochemistry
and Structural Biology, Center for Molecular Protein Science, Lund University, P.O.
Box 124, SE 221 00, Lund, Sweden
| | - Sara Linse
- Department of Biochemistry
and Structural Biology, Center for Molecular Protein Science, Lund University, P.O.
Box 124, SE 221 00, Lund, Sweden
| | - Celia Cabaleiro-Lago
- Department of Biochemistry
and Structural Biology, Center for Molecular Protein Science, Lund University, P.O.
Box 124, SE 221 00, Lund, Sweden
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20
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Malisauskas R, Botyriute A, Cannon JG, Smirnovas V. Flavone derivatives as inhibitors of insulin amyloid-like fibril formation. PLoS One 2015; 10:e0121231. [PMID: 25799281 PMCID: PMC4370379 DOI: 10.1371/journal.pone.0121231] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 01/12/2015] [Indexed: 11/18/2022] Open
Abstract
Several natural and synthetic flavone derivatives have been reported to inhibit formation of amyloid fibrils or to remodel existing fibrils. These studies suggest that the numbers and positions of hydroxyl groups on the flavone rings determine their effectiveness as amyloid inhibitors. In many studies the primary method for determining the effectiveness of inhibition is measuring Thioflavin T (ThT) fluorescence. This method demonstrably results in a number of false positives for inhibition. We studied the effects of 265 commercially available flavone derivatives on insulin fibril formation. We enhanced the effectiveness of ThT fluorescence measurements by fitting kinetic curves to obtain halftime of aggregation (t50). Maximal values of ThT fluorescence varied two fold or more in one third of all cases, but this did not correlate with changes in t50. Changes in t50 values were more accurate measures of inhibition of amyloid formation. We showed that without a change in an assay, but just by observing complete kinetic curves it is possible to eliminate numbers of false positive and sometimes even false negative results. Examining the data from all 265 flavones we confirmed previous observations that identified the importance of hydroxyl groups for inhibition. Our evidence suggests the importance of hydroxyl groups at locations 5, 6, 7, and 4', and the absence of a hydroxyl group at location 3, for inhibiting amyloid formation. However, the main conclusion is that the positions are not additive. The structures and their effects must be thought of in the context of the whole molecule.
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Affiliation(s)
- Ricardas Malisauskas
- Department of Biothermodynamics and Drug Design, Vilnius University Institute of Biotechnology, Vilnius, Lithuania
- Department of Chemistry and Bioengineering, Vilnius Gediminas Technical University, Vilnius, Lithuania
| | - Akvile Botyriute
- Department of Biothermodynamics and Drug Design, Vilnius University Institute of Biotechnology, Vilnius, Lithuania
| | - Jonathan G. Cannon
- Department of Natural Sciences and Engineering, Middle Georgia State College, Cochran, Georgia, USA
| | - Vytautas Smirnovas
- Department of Biothermodynamics and Drug Design, Vilnius University Institute of Biotechnology, Vilnius, Lithuania
- * E-mail:
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21
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Effect of acidic and basic pH on Thioflavin T absorbance and fluorescence. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2015; 44:249-61. [PMID: 25794693 DOI: 10.1007/s00249-015-1019-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 02/22/2015] [Accepted: 03/06/2015] [Indexed: 12/19/2022]
Abstract
Thioflavin T (ThT) is a fluorescent dye able to enhance significantly its fluorescence quantum yield upon binding to protein amyloids. ThT assay is widely used to detect and quantify amyloids in a variety of conditions, including solutions with different pH levels. In the present work, the effect of acidic and basic pH on the conformation of the ThT molecule and its absorption and fluorescence properties was studied. The results show that both acidic and basic pH decrease significantly the intensity of ThT absorption in the visible region and fluorescence emission intensity. Low pHs induce an immediate "all-or-nothing" decrease in the ThT signal, while in alkaline solutions the ThT signal decreases gradually over time. pH-induced signal quenching is less in the presence of glycerol or protein aggregates. Two different mechanisms are responsible for the ThT signal quenching-the ThT hydroxylation at basic pH and protonation of the nitrogen atom of the dimethylamino group at acidic pH. ThT assays should be carefully carried out at basic or acidic pH as strong pH dependence of ThT could be responsible for misinterpretation and false positive/negative experimental results. The potential unsuitability of ThT as a probe in solutions with high pH (>9) has been shown.
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22
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Wang Y, Modena MM, Platen M, Schaap IAT, Burg TP. Label-Free Measurement of Amyloid Elongation by Suspended Microchannel Resonators. Anal Chem 2015; 87:1821-8. [DOI: 10.1021/ac503845f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Yu Wang
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Mario Matteo Modena
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Mitja Platen
- Third
Institute of Physics, University of Goettingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Iwan Alexander Taco Schaap
- Third
Institute of Physics, University of Goettingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37073 Göttingen, Germany
| | - Thomas Peter Burg
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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23
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Caputo N, Jackson MA, Castle JR, El Youssef J, Bakhtiani PA, Bergstrom CP, Carroll JM, Breen ME, Leonard GL, David LL, Roberts CT, Ward WK. Biochemical stabilization of glucagon at alkaline pH. Diabetes Technol Ther 2014; 16:747-58. [PMID: 24968220 PMCID: PMC4201307 DOI: 10.1089/dia.2014.0047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND For patients with type 1 diabetes mellitus, a bihormonal artificial endocrine pancreas system utilizing glucagon and insulin has been found to stabilize glycemic control. However, commercially available formulations of glucagon cannot currently be used in such systems because of physical instability characterized by aggregation and chemical degradation. Storing glucagon at pH 10 blocks protein aggregation but results in chemical degradation. Reductions in pH minimize chemical degradation, but even small reductions increase protein aggregation. We hypothesized that common pharmaceutical excipients accompanied by a new excipient would inhibit glucagon aggregation at an alkaline pH. METHODS AND RESULTS As measured by tryptophan intrinsic fluorescence shift and optical density at 630 nm, protein aggregation was indeed minimized when glucagon was formulated with curcumin and albumin. This formulation also reduced chemical degradation, measured by liquid chromatography with mass spectrometry. Biological activity was retained after aging for 7 days in an in vitro cell-based bioassay and also in Yorkshire swine. CONCLUSIONS Based on these findings, a formulation of glucagon stabilized with curcumin, polysorbate-80, l-methionine, and albumin at alkaline pH in glycine buffer may be suitable for extended use in a portable pump in the setting of a bihormonal artificial endocrine pancreas.
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Affiliation(s)
- Nicholas Caputo
- Harold Schnitzer Diabetes Health Center, Oregon Health and Science University, Portland, Oregon
| | - Melanie A. Jackson
- School of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Jessica R. Castle
- Harold Schnitzer Diabetes Health Center, Oregon Health and Science University, Portland, Oregon
- School of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Joseph El Youssef
- Harold Schnitzer Diabetes Health Center, Oregon Health and Science University, Portland, Oregon
- School of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Parkash A. Bakhtiani
- Harold Schnitzer Diabetes Health Center, Oregon Health and Science University, Portland, Oregon
- School of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Colin P. Bergstrom
- School of Medicine, Oregon Health and Science University, Portland, Oregon
| | - Julie M. Carroll
- Oregon National Primate Research Center, Oregon Health and Science University, Portland, Oregon
| | - Matthew E. Breen
- Harold Schnitzer Diabetes Health Center, Oregon Health and Science University, Portland, Oregon
| | - Gerald L. Leonard
- Harold Schnitzer Diabetes Health Center, Oregon Health and Science University, Portland, Oregon
| | - Larry L. David
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon
| | - Charles T. Roberts
- School of Medicine, Oregon Health and Science University, Portland, Oregon
- Oregon National Primate Research Center, Oregon Health and Science University, Portland, Oregon
| | - W. Kenneth Ward
- Harold Schnitzer Diabetes Health Center, Oregon Health and Science University, Portland, Oregon
- School of Medicine, Oregon Health and Science University, Portland, Oregon
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24
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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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25
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Liu S, Yang H, Wan L, Cheng J, Lu X. Penetratin-mediated delivery enhances the antitumor activity of the cationic antimicrobial peptide Magainin II. Cancer Biother Radiopharm 2013; 28:289-97. [PMID: 23286306 DOI: 10.1089/cbr.2012.1328] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cationic antimicrobial peptides (CAPs) with antitumor activity have potential for use as novel antitumor agents because of their lower risk for induction of resistance. Of these peptides, magainin II (MG2) exhibited cytotoxicity in tumor cells only at high concentrations, likely due to the inefficiency of MG2 in cell membrane binding and cell entry. Conjugation to a cell-penetrating peptide (CPP) might enhance the cytotoxicity of MG2 in tumor cells. Here, we constructed a fusion peptide MG2A by conjugating MG2 to the N-terminus of the CPP penetratin (Antp). It was found that the fusion peptide MG2A is more potent than unconjugated MG2 at tumor cell killing. The IC50s of MG2A for the tumor cells tested were at least 30 times lower than the IC50s of unconjugated MG2. These data indicate that conjugation to Antp significantly enhanced the cytotoxicity of MG2 in tumor cells. Moreover, the IC50s of MG2A for tumor cells are within 2 to 3 μM, which are about three to five times lower than the IC50 for normal cells. Furthermore, chondroitin sulfate (CS) was found to be overexpressed on the surface of the tested tumor cells, and the cytotoxicity of MG2A could be inhibited by the addition of exogenous CS. These results suggest that binding of Antp to CS on tumor cells might be one important cause for the selective cytotoxicity of MG2A in tumor cells. Taken together, conjugation of MG2 to Antp can significantly enhance its antitumor activity, and the fusion of CAP to Antp might be an alternative for cancer-targeted therapy.
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Affiliation(s)
- Shan Liu
- Key Lab of Transplant Engineering and Immunology, Ministry of Health, West China Hospital, Sichuan University , Chengdu 610041, China
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26
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Liu L, Shao Y, Peng J, Liu H, Zhang L. Selective recognition of ds-DNA cavities by a molecular rotor: switched fluorescence of thioflavin T. MOLECULAR BIOSYSTEMS 2013; 9:2512-9. [DOI: 10.1039/c3mb70201d] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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27
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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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