1
|
Gucký A, Hamuľaková S. Targeting Biometals in Alzheimer's Disease with Metal Chelating Agents Including Coumarin Derivatives. CNS Drugs 2024; 38:507-532. [PMID: 38829443 PMCID: PMC11182807 DOI: 10.1007/s40263-024-01093-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/29/2024] [Indexed: 06/05/2024]
Abstract
Numerous physiological processes happening in the human body, including cerebral development and function, require the participation of biometal ions such as iron, copper, and zinc. Their dyshomeostasis may, however, contribute to the onset of Alzheimer's disease (AD) and potentially other neurodegenerative diseases. Chelation of biometal ions is therefore a therapeutic strategy against AD. This review provides a survey of natural and synthetic chelating agents that are or could potentially be used to target the metal hypothesis of AD. Since metal dyshomeostasis is not the only pathological aspect of AD, and the nature of this disorder is very complex and multifactiorial, the most efficient therapeutics should target as many neurotoxic factors as possible. Various coumarin derivatives match this description and apart from being able to chelate metal ions, they exhibit the capacity to inhibit cholinesterases (ChEs) and monoamine oxidase B (MAO-B) while also possessing antioxidant, anti-inflammatory, and numerous other beneficial effects. Compounds based on the coumarin scaffold therefore represent a desirable class of anti-AD therapeutics.
Collapse
Affiliation(s)
- Adrián Gucký
- Department of Biochemistry, Institute of Chemical Sciences, Faculty of Science, P. J. Šafárik University in Košice, Moyzesova 11, 040 01, Kosice, Slovak Republic
| | - Slávka Hamuľaková
- Department of Organic Chemistry, Institute of Chemical Sciences, Faculty of Science, P. J. Šafárik University in Košice, Moyzesova 11, 040 01, Kosice, Slovak Republic.
| |
Collapse
|
2
|
Tan RX, Li WH, Pang JM, Zhong SM, Huang XY, Deng JZ, Zhou LY, Wu JQ, Wang XQ. Design, synthesis, and evaluation of 2,2'-bipyridyl derivatives as bifunctional agents against Alzheimer's disease. Mol Divers 2023:10.1007/s11030-023-10651-5. [PMID: 37119457 DOI: 10.1007/s11030-023-10651-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 04/14/2023] [Indexed: 05/01/2023]
Abstract
Alzheimer's disease (AD) is a complex multifactorial neurodegenerative disease. Metal ion dyshomeostasis and Aβ aggregation have been proposed to contribute to AD progression. Metal ions can bind to Aβ and promote Aβ aggregation, and ultimately lead to neuronal death. Bifunctional (metal chelation and Aβ interaction) compounds are showing promise against AD. In this work, eleven new 3,3'-diamino-2,2'-bipyridine derivatives 4a-4k were synthesized, and evaluated as bifunctional agents for AD treatment. In vitro Aβ aggregation inhibition assay confirmed that most of the synthesized compounds exhibited significant self-induced Aβ1-42 aggregation inhibition. Among them, compound 4d displayed the best inhibitory potency of self-induced Aβ1-42 aggregation with IC50 value of 9.4 µM, and it could selectively chelate with Cu2+ and exhibited 66.2% inhibition of Cu2+-induced Aβ1-42 aggregation. Meanwhile, compound 4d showed strong neuroprotective activity against Aβ1-42 and Cu2+-treated Aβ1-42 induced cell damage. Moreover, compound 4d in high dose significantly reversed Aβ-induced memory impairment in mice.
Collapse
Affiliation(s)
- Ren-Xian Tan
- School of Pharmacy, Guangdong Medical University, Dongguan, 523808, Guangdong, China
| | - Wei-Hao Li
- School of Pharmacy, Guangdong Medical University, Dongguan, 523808, Guangdong, China
| | - Jia-Min Pang
- School of Pharmacy, Guangdong Medical University, Dongguan, 523808, Guangdong, China
| | - Si-Min Zhong
- School of Pharmacy, Guangdong Medical University, Dongguan, 523808, Guangdong, China
| | - Xin-Yi Huang
- School of Pharmacy, Guangdong Medical University, Dongguan, 523808, Guangdong, China
| | - Jun-Ze Deng
- School of Pharmacy, Guangdong Medical University, Dongguan, 523808, Guangdong, China
| | - Lu-Yi Zhou
- School of Pharmacy, Guangdong Medical University, Dongguan, 523808, Guangdong, China
| | - Jia-Qiang Wu
- School of Biotechnology and Health Sciences, Wuyi University, Jiangmen, 529020, China
| | - Xiao-Qin Wang
- School of Pharmacy, Guangdong Medical University, Dongguan, 523808, Guangdong, China.
| |
Collapse
|
3
|
Puentes-Díaz N, Chaparro D, Morales-Morales D, Flores-Gaspar A, Alí-Torres J. Role of Metal Cations of Copper, Iron, and Aluminum and Multifunctional Ligands in Alzheimer's Disease: Experimental and Computational Insights. ACS OMEGA 2023; 8:4508-4526. [PMID: 36777601 PMCID: PMC9909689 DOI: 10.1021/acsomega.2c06939] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 12/30/2022] [Indexed: 05/15/2023]
Abstract
Alzheimer's disease (AD) is the most common form of dementia, affecting millions of people around the world. Even though the causes of AD are not completely understood due to its multifactorial nature, some neuropathological hallmarks of its development have been related to the high concentration of some metal cations. These roles include the participation of these metal cations in the production of reactive oxygen species, which have been involved in neuronal damage. In order to avoid the increment in the oxidative stress, multifunctional ligands used to coordinate these metal cations have been proposed as a possible treatment to AD. In this review, we present the recent advances in experimental and computational works aiming to understand the role of two redox active and essential transition-metal cations (Cu and Fe) and one nonbiological metal (Al) and the recent proposals on the development of multifunctional ligands to stop or revert the damaging effects promoted by these metal cations.
Collapse
Affiliation(s)
- Nicolás Puentes-Díaz
- Departamento
de Química, Universidad Nacional
de Colombia−Sede Bogotá, Bogotá 11301, Colombia
| | - Diego Chaparro
- Departamento
de Química, Universidad Nacional
de Colombia−Sede Bogotá, Bogotá 11301, Colombia
- Departamento
de Química, Universidad Militar Nueva
Granada, Cajicá 250240, Colombia
| | - David Morales-Morales
- Instituto
de Química, Universidad Nacional Autónoma de México,
Circuito Exterior, Ciudad Universitaria, Ciudad de México 04510, México
| | - Areli Flores-Gaspar
- Departamento
de Química, Universidad Militar Nueva
Granada, Cajicá 250240, Colombia
- Areli Flores-Gaspar − Departamento de Química,
Universidad Militar Nueva
Granada, Cajicá, 250247, Colombia.
| | - Jorge Alí-Torres
- Departamento
de Química, Universidad Nacional
de Colombia−Sede Bogotá, Bogotá 11301, Colombia
- Jorge Alí-Torres − Departamento de Química, Universidad Nacional de
Colombia, Sede Bogotá,11301, Bogotá, Colombia.
| |
Collapse
|
4
|
Han J, Yoon J, Shin J, Nam E, Qian T, Li Y, Park K, Lee SH, Lim MH. Conformational and functional changes of the native neuropeptide somatostatin occur in the presence of copper and amyloid-β. Nat Chem 2022; 14:1021-1030. [PMID: 35817963 DOI: 10.1038/s41557-022-00984-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 05/26/2022] [Indexed: 11/09/2022]
Abstract
The progression of neurodegenerative disorders can lead to impaired neurotransmission; however, the role of pathogenic factors associated with these diseases and their impact on the structures and functions of neurotransmitters have not been clearly established. Here we report the discovery that conformational and functional changes of a native neuropeptide, somatostatin (SST), occur in the presence of copper ions, metal-free amyloid-β (Aβ) and metal-bound Aβ (metal-Aβ) found as pathological factors in the brains of patients with Alzheimer's disease. These pathological elements induce the self-assembly of SST and, consequently, prevent it from binding to the receptor. In the reverse direction, SST notably modifies the aggregation profiles of Aβ species in the presence of metal ions, attenuating their cytotoxicity and interactions with cell membranes. Our work demonstrates a loss of normal function of SST as a neurotransmitter and a gain of its modulative function against metal-Aβ under pathological conditions.
Collapse
Affiliation(s)
- Jiyeon Han
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Jiwon Yoon
- Department of Biological Sciences, KAIST, Daejeon, Republic of Korea
| | - Jeongcheol Shin
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Eunju Nam
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Tongrui Qian
- State Key Laboratory Membrane Biology, Peking University School of Life Sciences, Beijing, China
| | - Yulong Li
- State Key Laboratory Membrane Biology, Peking University School of Life Sciences, Beijing, China.,PKU-IDG/McGovern Institute for Brain Research, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Kiyoung Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
| | - Seung-Hee Lee
- Department of Biological Sciences, KAIST, Daejeon, Republic of Korea.
| | - Mi Hee Lim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
| |
Collapse
|
5
|
Xi Y, Chen Y, Jin Y, Han G, Song M, Song T, Shi Y, Tao L, Huang Z, Zhou J, Ding Y, Zhang H. Versatile nanomaterials for Alzheimer's disease: Pathogenesis inspired disease-modifying therapy. J Control Release 2022; 345:38-61. [DOI: 10.1016/j.jconrel.2022.02.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/25/2022] [Accepted: 02/26/2022] [Indexed: 12/11/2022]
|
6
|
Evidence of cadmium and mercury involvement in the Aβ42 aggregation process. Biophys Chem 2020; 266:106453. [DOI: 10.1016/j.bpc.2020.106453] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/30/2020] [Accepted: 08/02/2020] [Indexed: 12/11/2022]
|
7
|
Metal complexes that bind to the amyloid-β peptide of relevance to Alzheimer’s disease. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213255
expr 886172045 + 931245952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
|
8
|
Gomes LM, Bataglioli JC, Storr T. Metal complexes that bind to the amyloid-β peptide of relevance to Alzheimer’s disease. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213255] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
9
|
Gomes LMF, Bataglioli JC, Jussila AJ, Smith JR, Walsby CJ, Storr T. Modification of Aβ Peptide Aggregation via Covalent Binding of a Series of Ru(III) Complexes. Front Chem 2019; 7:838. [PMID: 31921764 PMCID: PMC6915085 DOI: 10.3389/fchem.2019.00838] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 11/18/2019] [Indexed: 12/31/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia, leading to loss of cognition, and eventually death. The disease is characterized by the formation of extracellular aggregates of the amyloid-beta (Aβ) peptide and neurofibrillary tangles of tau protein inside cells, and oxidative stress. In this study, we investigate a series of Ru(III) complexes (Ru-N) derived from NAMI-A in which the imidazole ligand has been substituted for pyridine derivatives, as potential therapeutics for AD. The ability of the Ru-N series to bind to Aβ was evaluated by NMR and ESI-MS, and their influence on the Aβ peptide aggregation process was investigated via electrophoresis gel/western blot, TEM, turbidity, and Bradford assays. The complexes were shown to bind covalently to the Aβ peptide, likely via a His residue. Upon binding, the complexes promote the formation of soluble high molecular weight aggregates, in comparison to peptide precipitation for peptide alone. In addition, TEM analysis supports both amorphous and fibrillar aggregate morphology for Ru-N treatments, while only large amorphous aggregates are observed for peptide alone. Overall, our results show that the Ru-N complexes modulate Aβ peptide aggregation, however, the change in the size of the pyridine ligand does not substantially alter the Aβ aggregation process.
Collapse
Affiliation(s)
- Luiza M F Gomes
- Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada
| | | | - Allison J Jussila
- Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Jason R Smith
- Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Charles J Walsby
- Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Tim Storr
- Department of Chemistry, Simon Fraser University, Burnaby, BC, Canada
| |
Collapse
|
10
|
Gomes LMF, Mahammed A, Prosser KE, Smith JR, Silverman MA, Walsby CJ, Gross Z, Storr T. A catalytic antioxidant for limiting amyloid-beta peptide aggregation and reactive oxygen species generation. Chem Sci 2018; 10:1634-1643. [PMID: 30842826 PMCID: PMC6369440 DOI: 10.1039/c8sc04660c] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 11/27/2018] [Indexed: 12/29/2022] Open
Abstract
Alzheimer's disease (AD) is a multifaceted disease that is characterized by increased oxidative stress, metal-ion dysregulation, and the formation of intracellular neurofibrillary tangles and extracellular amyloid-β (Aβ) aggregates. In this work we report the large affinity binding of the iron(iii) 2,17-bis-sulfonato-5,10,15-tris(pentafluorophenyl)corrole complex FeL1 to the Aβ peptide (K d ∼ 10-7) and the ability of the bound FeL1 to act as a catalytic antioxidant in both the presence and absence of Cu(ii) ions. Specific findings are that: (a) an Aβ histidine residue binds axially to FeL1; (b) that the resulting adduct is an efficient catalase; (c) this interaction restricts the formation of high molecular weight peptide aggregates. UV-Vis and electron paramagnetic resonance (EPR) studies show that although the binding of FeL1 does not influence the Aβ-Cu(ii) interaction (K d ∼ 10-10), bound FeL1 still acts as an antioxidant thereby significantly limiting reactive oxygen species (ROS) generation from Aβ-Cu. Overall, FeL1 is shown to bind to the Aβ peptide, and modulate peptide aggregation. In addition, FeL1 forms a ternary species with Aβ-Cu(ii) and impedes ROS generation, thus showing the promise of discrete metal complexes to limit the toxicity pathways of the Aβ peptide.
Collapse
Affiliation(s)
- Luiza M F Gomes
- Department of Chemistry , Simon Fraser University , V5A-1S6 , Burnaby , BC , Canada .
| | - Atif Mahammed
- Schulich Faculty of Chemistry , Technion-Israel Institute of Technology , Haifa , 32000 , Israel .
| | - Kathleen E Prosser
- Department of Chemistry , Simon Fraser University , V5A-1S6 , Burnaby , BC , Canada .
| | - Jason R Smith
- Department of Chemistry , Simon Fraser University , V5A-1S6 , Burnaby , BC , Canada .
| | - Michael A Silverman
- Department of Biological Sciences , Simon Fraser University , V5A-1S6 , Burnaby , BC , Canada
| | - Charles J Walsby
- Department of Chemistry , Simon Fraser University , V5A-1S6 , Burnaby , BC , Canada .
| | - Zeev Gross
- Schulich Faculty of Chemistry , Technion-Israel Institute of Technology , Haifa , 32000 , Israel .
| | - Tim Storr
- Department of Chemistry , Simon Fraser University , V5A-1S6 , Burnaby , BC , Canada .
| |
Collapse
|
11
|
Savelieff MG, Nam G, Kang J, Lee HJ, Lee M, Lim MH. Development of Multifunctional Molecules as Potential Therapeutic Candidates for Alzheimer’s Disease, Parkinson’s Disease, and Amyotrophic Lateral Sclerosis in the Last Decade. Chem Rev 2018; 119:1221-1322. [DOI: 10.1021/acs.chemrev.8b00138] [Citation(s) in RCA: 270] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Masha G. Savelieff
- SciGency Science Communications, Ann Arbor, Michigan 48104, United States
| | - Geewoo Nam
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Juhye Kang
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Hyuck Jin Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Misun Lee
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Mi Hee Lim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| |
Collapse
|
12
|
Soper-Hopper MT, Eschweiler JD, Ruotolo BT. Ion Mobility-Mass Spectrometry Reveals a Dipeptide That Acts as a Molecular Chaperone for Amyloid β. ACS Chem Biol 2017; 12:1113-1120. [PMID: 28240851 DOI: 10.1021/acschembio.7b00045] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Previously, we discovered and structurally characterized a complex between amyloid β 1-40 and the neuropeptide leucine enkephalin. This work identified leucine enkephalin as a potentially useful starting point for the discovery of peptide-related biotherapeutics for Alzheimer's disease. In order to better understand such complexes that are formed in vitro, we describe here the analysis of a series of site-directed amino acid substitution variants of both peptides, covering the leucine enkephalin sequence in its entirety and a large number of selected residues of amyloid β 1-40 (residues: D1, E3, F4, R5, H6, Y10, E11, H13, H14, Q15, K16, E22, K28, and V40). Ion mobility-mass spectrometry measurements and molecular dynamics simulations reveal that the hydrophobic C-terminus of leucine enkephalin (Phe-Leu, FL) is crucial for the formation of peptide complexes. As such, we explore here the interaction of the dipeptide FL with both wildtype and variant forms of amyloid β in order to structurally characterize the complexes formed. We find that FL binds preferentially to amyloid β oligomers and attaches to amyloid β within the region between its N-terminus and its hydrophobic core, most specifically at residues Y10 and Q15. We further show that FL is able to prevent fibril formation.
Collapse
Affiliation(s)
- Molly T. Soper-Hopper
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joseph D. Eschweiler
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brandon T. Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| |
Collapse
|
13
|
Shokrollahi A, Zare E. Determination of acidity constants of bromophenol blue and phenol red indicators by solution scanometric method and comparison with spectrophotometric results. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2016.01.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
14
|
Shokrollahi A, Firoozbakht. F. Determination of the acidity constants of neutral red and bromocresol green by solution scanometric method and comparison with spectrophotometric results. BENI-SUEF UNIVERSITY JOURNAL OF BASIC AND APPLIED SCIENCES 2016. [DOI: 10.1016/j.bjbas.2016.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
15
|
Lee HJ, Kerr RA, Korshavn KJ, Lee J, Kang J, Ramamoorthy A, Ruotolo BT, Lim MH. Effects of hydroxyl group variations on a flavonoid backbone toward modulation of metal-free and metal-induced amyloid-β aggregation. Inorg Chem Front 2016. [DOI: 10.1039/c5qi00219b] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structural variations of a flavonoid framework noticeably tune the interaction and reactivity of flavonoids with metals, Aβ, and metal–Aβ.
Collapse
Affiliation(s)
- Hyuck Jin Lee
- Department of Chemistry
- Ulsan National Institute of Science and Technology (UNIST)
- Ulsan 44919
- Korea
- Department of Chemistry
| | | | | | - Jeeyeon Lee
- Department of Chemistry
- Ulsan National Institute of Science and Technology (UNIST)
- Ulsan 44919
- Korea
| | - Juhye Kang
- Department of Chemistry
- Ulsan National Institute of Science and Technology (UNIST)
- Ulsan 44919
- Korea
| | | | | | - Mi Hee Lim
- Department of Chemistry
- Ulsan National Institute of Science and Technology (UNIST)
- Ulsan 44919
- Korea
| |
Collapse
|
16
|
Li X, Dong X, Liu Y, Meng Y, Zhang Y, Zhang D, Liu C. Ultraviolet irradiation-mediated formation of Aβ42 oligomers and reactive oxygen species in Zn2+-bound Aβ42 aggregates irrespective of the removal of Zn2+. NEW J CHEM 2016. [DOI: 10.1039/c6nj02004f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The controlled UV light exposure converts redox-inert Zn2+-bound Aβ42 aggregates into cytotoxic Aβ42 oligomers and reactive oxygen species.
Collapse
Affiliation(s)
- Xiang Li
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education, and School of Chemistry
- Central China Normal University
- Wuhan 430079
- People's Republic of China
| | - Xiongwei Dong
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education, and School of Chemistry
- Central China Normal University
- Wuhan 430079
- People's Republic of China
| | - Yaojing Liu
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education, and School of Chemistry
- Central China Normal University
- Wuhan 430079
- People's Republic of China
| | - Yan Meng
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education, and School of Chemistry
- Central China Normal University
- Wuhan 430079
- People's Republic of China
| | - Yong Zhang
- School of Chemical and Materials Engineering
- Hubei Polytechnic University
- Huangshi 435003
- People's Republic of China
| | - Dan Zhang
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education, and School of Chemistry
- Central China Normal University
- Wuhan 430079
- People's Republic of China
| | - Changlin Liu
- Key Laboratory of Pesticide & Chemical Biology
- Ministry of Education, and School of Chemistry
- Central China Normal University
- Wuhan 430079
- People's Republic of China
| |
Collapse
|
17
|
Korshavn KJ, Jang M, Kwak YJ, Kochi A, Vertuani S, Bhunia A, Manfredini S, Ramamoorthy A, Lim MH. Reactivity of Metal-Free and Metal-Associated Amyloid-β with Glycosylated Polyphenols and Their Esterified Derivatives. Sci Rep 2015; 5:17842. [PMID: 26657338 PMCID: PMC4674742 DOI: 10.1038/srep17842] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Accepted: 11/05/2015] [Indexed: 12/19/2022] Open
Abstract
Both amyloid-β (Aβ) and transition metal ions are shown to be involved in the pathogenesis of Alzheimer's disease (AD), though the importance of their interactions remains unclear. Multifunctional molecules, which can target metal-free and metal-bound Aβ and modulate their reactivity (e.g., Aβ aggregation), have been developed as chemical tools to investigate their function in AD pathology; however, these compounds generally lack specificity or have undesirable chemical and biological properties, reducing their functionality. We have evaluated whether multiple polyphenolic glycosides and their esterified derivatives can serve as specific, multifunctional probes to better understand AD. The ability of these compounds to interact with metal ions and metal-free/-associated Aβ, and further control both metal-free and metal-induced Aβ aggregation was investigated through gel electrophoresis with Western blotting, transmission electron microscopy, UV-Vis spectroscopy, fluorescence spectroscopy, and NMR spectroscopy. We also examined the cytotoxicity of the compounds and their ability to mitigate the toxicity induced by both metal-free and metal-bound Aβ. Of the polyphenols investigated, the natural product (Verbascoside) and its esterified derivative (VPP) regulate the aggregation and cytotoxicity of metal-free and/or metal-associated Aβ to different extents. Our studies indicate Verbascoside represents a promising structure for further multifunctional tool development against both metal-free Aβ and metal-Aβ.
Collapse
Affiliation(s)
- Kyle J. Korshavn
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Milim Jang
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Yeon Ju Kwak
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Akiko Kochi
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Silvia Vertuani
- Department of Life Sciences and Biotechnology, University of Ferrara, I-44121 Ferrara, Italy
| | - Anirban Bhunia
- Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VII(M), Kolkata 700054, India
| | - Stefano Manfredini
- Department of Life Sciences and Biotechnology, University of Ferrara, I-44121 Ferrara, Italy
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
- Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Mi Hee Lim
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| |
Collapse
|
18
|
Malishev R, Nandi S, Kolusheva S, Levi-Kalisman Y, Klärner FG, Schrader T, Bitan G, Jelinek R. Toxicity inhibitors protect lipid membranes from disruption by Aβ42. ACS Chem Neurosci 2015; 6:1860-9. [PMID: 26317327 DOI: 10.1021/acschemneuro.5b00200] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Although the precise molecular factors linking amyloid β-protein (Aβ) to Alzheimer's disease (AD) have not been deciphered, interaction of Aβ with cellular membranes has an important role in the disease. However, most therapeutic strategies targeting Aβ have focused on interfering with Aβ self-assembly rather than with its membrane interactions. Here, we studied the impact of three toxicity inhibitors on membrane interactions of Aβ42, the longer form of Aβ, which is associated most strongly with AD. The inhibitors included the four-residue C-terminal fragment Aβ(39-42), the polyphenol (-)-epigallocatechin-3-gallate (EGCG), and the lysine-specific molecular tweezer, CLR01, all of which previously were shown to disrupt different steps in Aβ42 self-assembly. Biophysical experiments revealed that incubation of Aβ42 with each of the three modulators affected membrane interactions in a distinct manner. Interestingly, EGCG and CLR01 were found to have significant interaction with membranes themselves. However, membrane bilayer disruption was reduced when the compounds were preincubated with Aβ42, suggesting that binding of the assembly modulators to the peptide attenuated their membrane interactions. Importantly, our study reveals that even though the three tested compounds affect Aβ42 assembly differently, membrane interactions were significantly inhibited upon incubation of each compound with Aβ42, suggesting that preventing the interaction of Aβ42 with the membrane contributes substantially to inhibition of its toxicity by each compound. The data suggest that interference with membrane interactions is an important factor for Aβ42 toxicity inhibitors and should be taken into account in potential therapeutic strategies, in addition to disruption or remodeling of amyloid assembly.
Collapse
Affiliation(s)
- Ravit Malishev
- Department
of Chemistry, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Sukhendu Nandi
- Department
of Chemistry, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Sofiya Kolusheva
- Ilse
Katz Institute for Nanotechnology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Yael Levi-Kalisman
- Department
of Chemistry, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Frank-Gerrit Klärner
- Institute
of Organic Chemistry, University of Duisburg-Essen, Essen 45117, Germany
| | - Thomas Schrader
- Institute
of Organic Chemistry, University of Duisburg-Essen, Essen 45117, Germany
| | - Gal Bitan
- Department
of Neurology, David Geffen School of Medicine, Brain Research Institute,
and Molecular Biology Institute, University of California at Los Angeles, Los
Angeles, California 90095, United States
| | - Raz Jelinek
- Department
of Chemistry, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
- Ilse
Katz Institute for Nanotechnology, Ben Gurion University of the Negev, Beer Sheva 84105, Israel
| |
Collapse
|
19
|
Muthuraj B, Layek S, Balaji SN, Trivedi V, Iyer PK. Multiple function fluorescein probe performs metal chelation, disaggregation, and modulation of aggregated Aβ and Aβ-Cu complex. ACS Chem Neurosci 2015; 6:1880-91. [PMID: 26332658 DOI: 10.1021/acschemneuro.5b00205] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
An exceptional probe comprising indole-3-carboxaldehyde fluorescein hydrazone (FI) performs multiple tasks, namely, disaggregating amyloid β (Aβ) aggregates in different biomarker environments such as cerebrospinal fluid (CSF), Aβ1-40 fibrils, β-amyloid lysozyme aggregates (LA), and U87 MG human astrocyte cells. Additionally, the probe FI binds with Cu(2+) ions selectively, disrupts the Aβ aggregates that vary from few nanometers to micrometers, and prevents their reaggregation, thereby performing disaggregation and modulation of amyloid-β in the presence as well as absence of Cu(2+) ion. The excellent selectivity of probe FI for Cu(2+) was effectively utilized to modulate the assembly of metal-induced Aβ aggregates by metal chelation with the "turn-on" fluorescence via spirolactam ring opening of FI as well as the metal-free Aβ fibrils by noncovalent interactions. These results confirm that FI has exceptional ability to perform multifaceted tasks such as metal chelation in intracellular conditions using Aβ lysozyme aggregates in cellular environments by the disruption of β-sheet rich Aβ fibrils into disaggregated forms. Subsequently, it was confirmed that FI had the ability to cross the blood-brain barrier and it also modulated the metal induced Aβ fibrils in cellular environments by "turn-on" fluorescence, which are the most vital properties of a probe or a therapeutic agent. Furthermore, the morphology changes were examined by atomic force microscopy (AFM), polarizable optical microscopy (POM), fluorescence microscopy, and dynamic light scattering (DLS) studies. These results provide very valuable clues on the Aβ (CSF Aβ fibrils, Aβ1-40 fibrils, β-amyloid lysozyme aggregates) disaggregation behavior via in vitro studies, which constitute the first insights into intracellular disaggregation of Aβ by "turn-on" method thereby influencing amyloidogenesis.
Collapse
Affiliation(s)
- B. Muthuraj
- Department of Chemistry, and ‡Department of Biosciences
and Bioengineering, Indian Institute of Technology Guwahati-781039, Assam, India
| | - Sourav Layek
- Department of Chemistry, and ‡Department of Biosciences
and Bioengineering, Indian Institute of Technology Guwahati-781039, Assam, India
| | - S. N. Balaji
- Department of Chemistry, and ‡Department of Biosciences
and Bioengineering, Indian Institute of Technology Guwahati-781039, Assam, India
| | - Vishal Trivedi
- Department of Chemistry, and ‡Department of Biosciences
and Bioengineering, Indian Institute of Technology Guwahati-781039, Assam, India
| | - Parameswar Krishnan Iyer
- Department of Chemistry, and ‡Department of Biosciences
and Bioengineering, Indian Institute of Technology Guwahati-781039, Assam, India
| |
Collapse
|
20
|
Dong X, Zhang Z, Zhao D, Liu Y, Meng Y, Zhang Y, Zhang D, Liu C. Ultraviolet light triggers the conversion of Cu2+-bound Aβ42 aggregates into cytotoxic species in a copper chelation-independent manner. Sci Rep 2015; 5:13897. [PMID: 26350232 PMCID: PMC4563556 DOI: 10.1038/srep13897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 07/10/2015] [Indexed: 12/19/2022] Open
Abstract
Increasing evidence indicates that abnormal Cu2+ binding to Aβ peptides are responsible for the formation of soluble Aβ oligomers and ROS that play essential roles in AD pathogenesis. During studying the Cu2+-chelating treatment of Cu2+-bound Aβ42 aggregates, we found that UV light exposure pronouncedly enhances cytotoxicity of the chelator-treated and -untreated Cu2+-bound Aβ42 aggregates. This stimulated us to thoroughly investigate (1) either the chelation treatment or UV light exposure leads to the increased cytotoxicity of the aggregates, and (2) why the chelator-treated and -untreated Cu2+-bound Aβ42 aggregates exhibit the increased cytotoxicity following UV light exposure if the latter is the case. The data indicated that the controlled UV exposure induced the dissociation of Cu2+-free and -bound Aβ42 aggregates into SDS-stable soluble oligomers and the production of ROS including H2O2 in an UV light intensity- and time-dependent, but Cu2+ chelation-independent manner. Although we can't fully understand the meaning of this finding at the current stage, the fact that the UV illuminated Aβ42 aggregates can efficiently kill HeLa cells implies that the aggregates after UV light exposure could be used to decrease the viability of skin cancer cells through skin administration.
Collapse
Affiliation(s)
- Xiongwei Dong
- Key Laboratory of Pesticide &Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan 430079, Hubei
| | - Zhe Zhang
- Key Laboratory of Pesticide &Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan 430079, Hubei
| | - Dan Zhao
- Key Laboratory of Pesticide &Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan 430079, Hubei
| | - Yaojing Liu
- Key Laboratory of Pesticide &Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan 430079, Hubei
| | - Yan Meng
- Key Laboratory of Pesticide &Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan 430079, Hubei
| | - Yong Zhang
- School of Chemical and Materials Engineering, Hubei Polytechnic University, Huangshi, 435003 Hubei, China
| | - Dan Zhang
- Key Laboratory of Pesticide &Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan 430079, Hubei
| | - Changlin Liu
- Key Laboratory of Pesticide &Chemical Biology, Ministry of Education, and School of Chemistry, Central China Normal University, Wuhan 430079, Hubei
| |
Collapse
|
21
|
Fosso MY, LeVine H, Green KD, Tsodikov OV, Garneau-Tsodikova S. Effects of structural modifications on the metal binding, anti-amyloid activity, and cholinesterase inhibitory activity of chalcones. Org Biomol Chem 2015; 13:9418-26. [PMID: 26248214 DOI: 10.1039/c5ob01478f] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
As the number of individuals affected with Alzheimer's disease (AD) increases and the availability of drugs for AD treatment remains limited, the need to develop effective therapeutics for AD becomes more and more pressing. Strategies currently pursued include inhibiting acetylcholinesterase (AChE) and targeting amyloid-β (Aβ) peptides and metal-Aβ complexes. This work presents the design, synthesis, and biochemical evaluation of a series of chalcones, and assesses the relationship between their structures and their ability to bind metal ions and/or Aβ species, and inhibit AChE/BChE activity. Several chalcones were found to exhibit potent disaggregation of pre-formed N-biotinyl Aβ1-42 (bioAβ42) aggregates in vitro in the absence and presence of Cu(2+)/Zn(2+), while others were effective at inhibiting the action of AChE.
Collapse
Affiliation(s)
- Marina Y Fosso
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536-0596, USA.
| | | | | | | | | |
Collapse
|
22
|
Jiang N, Wang XB, Li ZR, Li SY, Xie SS, Huang M, Kong LY. Design of a structural framework with potential use to develop balanced multifunctional agents against Alzheimer's disease. RSC Adv 2015. [DOI: 10.1039/c4ra10692j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A series of small molecules had been designed, synthesized, and evaluated as multifunctional ligands against Alzheimer's disease (AD).
Collapse
Affiliation(s)
- Neng Jiang
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Xiao-Bing Wang
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Zhong-Rui Li
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Su-Yi Li
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Sai-Sai Xie
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Ming Huang
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Ling-Yi Kong
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| |
Collapse
|
23
|
DeToma AS, Krishnamoorthy J, Nam Y, Lee HJ, Brender JR, Kochi A, Lee D, Onnis V, Congiu C, Manfredini S, Vertuani S, Balboni G, Ramamoorthy A, Lim MH. Synthetic Flavonoids, Aminoisoflavones: Interaction and Reactivity with Metal-Free and Metal-Associated Amyloid-β Species. Chem Sci 2014; 5:4851-4862. [PMID: 25383163 PMCID: PMC4217218 DOI: 10.1039/c4sc01531b] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Metal ion homeostasis in conjunction with amyloid-β (Aβ) aggregation in the brain has been implicated in Alzheimer's disease (AD) pathogenesis. To uncover the interplay between metal ions and Aβ peptides, synthetic, multifunctional small molecules have been employed to modulate Aβ aggregation in vitro. Naturally occurring flavonoids have emerged as a valuable class of compounds for this purpose due to their ability to modulate both metal-free and metal-induced Aβ aggregation. Although, flavonoids have shown anti-amyloidogenic effects, the structural moieties of flavonoids responsible for such reactivity have not been fully identified. In order to understand the structure-interaction-reactivity relationship within the flavonoid family for metal-free and metal-associated Aβ, we designed, synthesized, and characterized a set of isoflavone derivatives, aminoisoflavones (1-4), that displayed reactivity (i.e., modulation of Aβ aggregation) in vitro. NMR studies revealed a potential binding site for aminoisoflavones between the N-terminal loop and central helix on prefibrillar Aβ different from the non-specific binding observed for other flavonoids. The absence or presence of the catechol group differentiated the binding affinities and enthalpy/entropy balance between aminoisoflavones and Aβ. Furthermore, having a catechol group influenced the binding mode with fibrillar Aβ. Inclusion of additional substituents moderately tuned the impact of aminoisoflavones on Aβ aggregation. Overall, through these studies, we obtained valuable insights on the requirements for parity among metal chelation, intermolecular interactions, and substituent variation for Aβ interaction.
Collapse
Affiliation(s)
- Alaina S. DeToma
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | - Janarthanan Krishnamoorthy
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
- Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | - Younwoo Nam
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109-2216, USA
- Department of Fine Chemistry, Seoul National University of Science and Technology, Seoul, Korea
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| | - Hyuck Jin Lee
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| | - Jeffrey R. Brender
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
- Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | - Akiko Kochi
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| | - Dongkuk Lee
- Department of Fine Chemistry, Seoul National University of Science and Technology, Seoul, Korea
| | - Valentina Onnis
- Department of Life Sciences and Biotechnology, University of Ferrara, I-44121 Ferrara, Italy
| | - Cenzo Congiu
- Department of Life Sciences and Biotechnology, University of Ferrara, I-44121 Ferrara, Italy
| | - Stefano Manfredini
- Department of Life and Environment Sciences, Pharmaceutical, Pharmacological and Nutraceutical Sciences Unit, University of Cagliari, I-09124 Cagliari, Italy
| | - Silvia Vertuani
- Department of Life and Environment Sciences, Pharmaceutical, Pharmacological and Nutraceutical Sciences Unit, University of Cagliari, I-09124 Cagliari, Italy
| | - Gianfranco Balboni
- Department of Life Sciences and Biotechnology, University of Ferrara, I-44121 Ferrara, Italy
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
- Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | - Mi Hee Lim
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109-2216, USA
- Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| |
Collapse
|
24
|
Sharma AK, Kim J, Prior JT, Hawco NJ, Rath NP, Kim J, Mirica LM. Small bifunctional chelators that do not disaggregate amyloid β fibrils exhibit reduced cellular toxicity. Inorg Chem 2014; 53:11367-76. [PMID: 25333939 PMCID: PMC4220862 DOI: 10.1021/ic500926c] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Indexed: 01/22/2023]
Abstract
Multifunctional metal chelators that can modulate the amyloid β (Aβ) peptide aggregation and its interaction with metal ions such as copper and zinc hold considerable promise as therapeutic agents for Alzheimer's disease (AD). However, specific rather than systemic metal chelation by these compounds is needed in order to limit any side effects. Reported herein are two novel small bifunctional chelators, 2-[2-hydroxy-4-(diethylamino)phenyl]benzothiazole (L1) and 2-(2-hydroxy-3-methoxyphenyl)benzothiazole (L2), in which the metal-binding donor atoms are integrated within a molecular framework derived from the amyloid-binding fluorescent dye thioflavin T (ThT). The metal-binding properties of L1 and L2 were probed by pH spectrophotometric titrations to determine their pKa values and the corresponding metal complex stability constants, and the isolated metal complexes were structurally characterized. The amyloid-fibril-binding properties of L1 and L2 were investigated by fluorescence titrations and ThT competition assays. Interestingly, L1 and L2 do not lead to the formation of neurotoxic Aβ42 oligomers in the presence or absence of metal ions, as observed by native gel electrophoresis, Western blotting, and transmission electron microscopy. In addition, L1 and L2 were able to reduce the cell toxicity of preformed Aβ42 oligomers and of the copper-stabilized Aβ42 oligomers. Given their ability to reduce the toxicity of soluble Aβ42 and Cu-Aβ42 species, L1 and L2 are promising lead compounds for the development of chemical agents that can control the neurotoxicity of soluble Aβ42 species in AD.
Collapse
Affiliation(s)
- Anuj K. Sharma
- Department of Chemistry, Washington University, One Brookings Drive, St. Louis, Missouri 63130-4899, United States
| | - Jaekwang Kim
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63108, United States
| | - John T. Prior
- Department of Chemistry, Washington University, One Brookings Drive, St. Louis, Missouri 63130-4899, United States
| | - Nicholas J. Hawco
- Department of Chemistry, Washington University, One Brookings Drive, St. Louis, Missouri 63130-4899, United States
| | - Nigam P. Rath
- Department
of Chemistry and Biochemistry, University
of Missouri—St. Louis, One University Boulevard, St. Louis, Missouri 63121-4400, United States
| | - Jungsu Kim
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63108, United States
| | - Liviu M. Mirica
- Department of Chemistry, Washington University, One Brookings Drive, St. Louis, Missouri 63130-4899, United States
| |
Collapse
|
25
|
Porter MR, Kochi A, Karty JA, Lim MH, Zaleski JM. Chelation-induced diradical formation as an approach to modulation of the amyloid-β aggregation pathway. Chem Sci 2014; 6:1018-1026. [PMID: 29560189 PMCID: PMC5811126 DOI: 10.1039/c4sc01979b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 10/30/2014] [Indexed: 11/21/2022] Open
Abstract
Current approaches toward modulation of metal-induced Aβ aggregation pathways involve the development of small molecules that bind metal ions, such as Cu(ii) and Zn(ii), and interact with Aβ. For this effort, we present the enediyne-containing ligand (Z)-N,N'-bis[1-pyridin-2-yl-meth(E)-ylidene]oct-4-ene-2,6-diyne-1,8-diamine (PyED), which upon chelation of Cu(ii) and Zn(ii) undergoes Bergman-cyclization to yield diradical formation. The ability of this chelation-triggered diradical to modulate Aβ aggregation is evaluated relative to the non-radical generating control pyridine-2-ylmethyl-(2-{[(pyridine-2-ylmethylene)-amino]-methyl}-benzyl)-amine (PyBD). Variable-pH, ligand UV-vis titrations reveal pKa = 3.81(2) for PyBD, indicating it exists mainly in the neutral form at experimental pH. Lipinski's rule parameters and evaluation of blood-brain barrier (BBB) penetration potential by the PAMPA-BBB assay suggest that PyED may be CNS+ and penetrate the BBB. Both PyED and PyBD bind Zn(ii) and Cu(ii) as illustrated by bathochromic shifts of their UV-vis features. Speciation diagrams indicate that Cu(ii)-PyBD is the major species at pH 6.6 with a nanomolar Kd, suggesting the ligand may be capable of interacting with Cu(ii)-Aβ species. In the presence of Aβ40/42 under hyperthermic conditions (43 °C), the radical-generating PyED demonstrates markedly enhanced activity (2-24 h) toward the modulation of Aβ species as determined by gel electrophoresis. Correspondingly, transmission electron microscopy images of these samples show distinct morphological changes to the fibril structure that are most prominent for Cu(ii)-Aβ cases. The loss of CO2 from the metal binding region of Aβ in MALDI-TOF mass spectra further suggests that metal-ligand-Aβ interaction with subsequent radical formation may play a role in the aggregation pathway modulation.
Collapse
Affiliation(s)
- Meghan R Porter
- Department of Chemistry , Indiana University , Bloomington , Indiana 47405 , USA .
| | - Akiko Kochi
- Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , USA.,Department of Chemistry , Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798 , Korea .
| | - Jonathan A Karty
- Department of Chemistry , Indiana University , Bloomington , Indiana 47405 , USA .
| | - Mi Hee Lim
- Department of Chemistry , Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798 , Korea . .,Life Sciences Institute , University of Michigan , Ann Arbor , Michigan 48109 , USA
| | - Jeffrey M Zaleski
- Department of Chemistry , Indiana University , Bloomington , Indiana 47405 , USA .
| |
Collapse
|
26
|
Savelieff MG, DeToma AS, Derrick JS, Lim MH. The ongoing search for small molecules to study metal-associated amyloid-β species in Alzheimer's disease. Acc Chem Res 2014; 47:2475-82. [PMID: 25080056 DOI: 10.1021/ar500152x] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The development of a cure for Alzheimer's disease (AD) has been impeded by an inability to pinpoint the root cause of this disorder. Although numerous potential pathological factors have been indicated, acting either individually or mutually, the molecular mechanisms leading to disease onset and progression have not been clear. Amyloid-β (Aβ), generated from proteolytic processing of the amyloid precursor protein (APP), and its aggregated forms, particularly oligomers, are suggested as key pathological features in AD-affected brains. Historically, highly concentrated metals are found colocalized within Aβ plaques. Metal binding to Aβ (metal-Aβ) generates/stabilizes potentially toxic Aβ oligomers, and produces reactive oxygen species (ROS) in vitro (redox active metal ions; plausible contribution to oxidative stress). Consequently, clarification of the relationship between Aβ, metal ions, and toxicity, including oxidative stress via metal-Aβ, can lead to a deeper understanding of AD development. To probe the involvement of metal-Aβ in AD pathogenesis, rationally designed and naturally occurring molecules have been examined as chemical tools to target metal-Aβ species, modulate the interaction between the metal and Aβ, and subsequently redirect their aggregation into nontoxic, off-pathway unstructured aggregates. These ligands are also capable of attenuating the generation of redox active metal-Aβ-induced ROS to mitigate oxidative stress. One rational design concept, the incorporation approach, installs a metal binding site into a framework known to interact with Aβ. This approach affords compounds with the simultaneous ability to chelate metal ions and interact with Aβ. Natural products capable of Aβ interaction have been investigated for their influence on metal-induced Aβ aggregation and have inspired the construction of synthetic analogues. Systematic studies of these synthetic or natural molecules could uncover relationships between chemical structures, metal/Aβ/metal-Aβ interactions, and inhibition of Aβ/metal-Aβ reactivity (i.e., aggregation modes of Aβ/metal-Aβ; associated ROS production), suggesting mechanisms to refine the design strategy. Interdisciplinary investigations have demonstrated that the designed molecules and natural products control the aggregation pathways of metal-Aβ species transforming their size/conformation distribution. The aptitude of these molecules to impact metal-Aβ aggregation pathways, either via inhibition of Aβ aggregate formation, most importantly of oligomers, or disaggregation of preformed fibrils, could originate from their formation of complexes with metal-Aβ. Potentially, these molecules could direct metal-Aβ size/conformational states into alternative nontoxic unstructured oligomers, and control the geometry at the Aβ-ligated metal center for limited ROS formation to lessen the overall toxicity induced by metal-Aβ. Complexation between small molecules and Aβ/metal-Aβ has been observed by nuclear magnetic resonance spectroscopy (NMR) and ion mobility-mass spectrometry (IM-MS) pointing to molecular level interactions, validating the design strategy. In addition, these molecules exhibit other attractive properties, such as antioxidant capacity, prevention of ROS production, potential blood-brain barrier (BBB) permeability, and reduction of Aβ-/metal-Aβ-induced cytotoxicity, making them desirable tools for unraveling AD complexity. In this Account, we summarize the recent development of small molecules, via both rational design and the selection and modification of natural products, as tools for investigating metal-Aβ complexes, to advance our understanding of their relation to AD pathology.
Collapse
Affiliation(s)
| | | | | | - Mi Hee Lim
- Department
of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| |
Collapse
|
27
|
Gomes LMF, Vieira RP, Jones MR, Wang MCP, Dyrager C, Souza-Fagundes EM, Da Silva JG, Storr T, Beraldo H. 8-Hydroxyquinoline Schiff-base compounds as antioxidants and modulators of copper-mediated Aβ peptide aggregation. J Inorg Biochem 2014; 139:106-16. [PMID: 25019963 DOI: 10.1016/j.jinorgbio.2014.04.011] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 04/15/2014] [Accepted: 04/15/2014] [Indexed: 12/20/2022]
Abstract
One of the hallmarks of Alzheimer's disease (AD) in the brain are amyloid-β (Aβ) plaques, and metal ions such as copper(II) and zinc(II) have been shown to play a role in the aggregation and toxicity of the Aβ peptide, the major constituent of these extracellular aggregates. Metal binding agents can promote the disaggregation of Aβ plaques, and have shown promise as AD therapeutics. Herein, we describe the syntheses and characterization of an acetohydrazone (8-H2QH), a thiosemicarbazone (8-H2QT), and a semicarbazone (8-H2QS) derived from 8-hydroxyquinoline. The three compounds are shown to be neutral at pH7.4, and are potent antioxidants as measured by a Trolox Equivalent Antioxidant Capacity (TEAC) assay. The ligands form complexes with Cu(II), 8-H2QT in a 1:1 metal:ligand ratio, and 8-H2QH and 8-H2QS in a 1:2 metal:ligand ratio. A preliminary aggregation inhibition assay using the Aβ1-40 peptide showed that 8-H2QS and 8-H2QH inhibit peptide aggregation in the presence of Cu(II). Native gel electrophoresis/Western blot and TEM images were obtained to give a more detailed picture of the extent and pathways of Aβ aggregation using the more neurotoxic Aβ1-42 in the presence and absence of Cu(II), 8-H2QH, 8-H2QS and the drug candidate PBT2. An increase in the formation of oligomeric species is evident in the presence of Cu(II). However, in the presence of ligands and Cu(II), the results match those for the peptide alone, suggesting that the ligands function by sequestering Cu(II) and limiting oligomer formation in this assay.
Collapse
Affiliation(s)
- Luiza M F Gomes
- Departamento de Química, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil; Department of Chemistry, Simon Fraser University, V5A-1S6 Burnaby, BC, Canada
| | - Rafael P Vieira
- Departamento de Química, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil; Department of Chemistry, Simon Fraser University, V5A-1S6 Burnaby, BC, Canada
| | - Michael R Jones
- Department of Chemistry, Simon Fraser University, V5A-1S6 Burnaby, BC, Canada
| | - Michael C P Wang
- Department of Chemistry, Simon Fraser University, V5A-1S6 Burnaby, BC, Canada
| | - Christine Dyrager
- Department of Chemistry, Simon Fraser University, V5A-1S6 Burnaby, BC, Canada
| | - Elaine M Souza-Fagundes
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil
| | - Jeferson G Da Silva
- Departamento de Química, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil
| | - Tim Storr
- Department of Chemistry, Simon Fraser University, V5A-1S6 Burnaby, BC, Canada.
| | - Heloisa Beraldo
- Departamento de Química, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil.
| |
Collapse
|
28
|
Sheynis T, Friediger A, Xue WF, Hellewell AL, Tipping KW, Hewitt EW, Radford SE, Jelinek R. Aggregation modulators interfere with membrane interactions of β2-microglobulin fibrils. Biophys J 2014; 105:745-55. [PMID: 23931322 DOI: 10.1016/j.bpj.2013.06.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 05/20/2013] [Accepted: 06/04/2013] [Indexed: 10/26/2022] Open
Abstract
Amyloid fibril accumulation is a pathological hallmark of several devastating disorders, including Alzheimer's disease, prion diseases, type II diabetes, and others. Although the molecular factors responsible for amyloid pathologies have not been deciphered, interactions of misfolded proteins with cell membranes appear to play important roles in these disorders. Despite increasing evidence for the involvement of membranes in amyloid-mediated cytotoxicity, the pursuit for therapeutic strategies has focused on preventing self-assembly of the proteins comprising the amyloid plaques. Here we present an investigation of the impact of fibrillation modulators upon membrane interactions of β2-microglobulin (β2m) fibrils. The experiments reveal that polyphenols (epigallocatechin gallate, bromophenol blue, and resveratrol) and glycosaminoglycans (heparin and heparin disaccharide) differentially affect membrane interactions of β2m fibrils measured by dye-release experiments, fluorescence anisotropy of labeled lipid, and confocal and cryo-electron microscopies. Interestingly, whereas epigallocatechin gallate and heparin prevent membrane damage as judged by these assays, the other compounds tested had little, or no, effect. The results suggest a new dimension to the biological impact of fibrillation modulators that involves interference with membrane interactions of amyloid species, adding to contemporary strategies for combating amyloid diseases that focus on disruption or remodeling of amyloid aggregates.
Collapse
Affiliation(s)
- Tania Sheynis
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Pan LF, Wang XB, Xie SS, Li SY, Kong LY. Multitarget-directed resveratrol derivatives: anti-cholinesterases, anti-β-amyloid aggregation and monoamine oxidase inhibition properties against Alzheimer's disease. MEDCHEMCOMM 2014. [DOI: 10.1039/c3md00376k] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Resveratrol derivatives were designed and synthesized as multitarget-directed agents for treating AD, and 6r was a balanced inhibitor toward all the tested targets.
Collapse
Affiliation(s)
- Long-Fei Pan
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Xiao-Bing Wang
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Sai-Sai Xie
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Su-Yi Li
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Ling-Yi Kong
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| |
Collapse
|
30
|
Lee S, Zheng X, Krishnamoorthy J, Savelieff MG, Park HM, Brender JR, Kim JH, Derrick JS, Kochi A, Lee HJ, Kim C, Ramamoorthy A, Bowers MT, Lim MH. Rational design of a structural framework with potential use to develop chemical reagents that target and modulate multiple facets of Alzheimer's disease. J Am Chem Soc 2013; 136:299-310. [PMID: 24397771 DOI: 10.1021/ja409801p] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Alzheimer's disease (AD) is characterized by multiple, intertwined pathological features, including amyloid-β (Aβ) aggregation, metal ion dyshomeostasis, and oxidative stress. We report a novel compound (ML) prototype of a rationally designed molecule obtained by integrating structural elements for Aβ aggregation control, metal chelation, reactive oxygen species (ROS) regulation, and antioxidant activity within a single molecule. Chemical, biochemical, ion mobility mass spectrometric, and NMR studies indicate that the compound ML targets metal-free and metal-bound Aβ (metal-Aβ) species, suppresses Aβ aggregation in vitro, and diminishes toxicity induced by Aβ and metal-treated Aβ in living cells. Comparison of ML to its structural moieties (i.e., 4-(dimethylamino)phenol (DAP) and (8-aminoquinolin-2-yl)methanol (1)) for reactivity with Aβ and metal-Aβ suggests the synergy of incorporating structural components for both metal chelation and Aβ interaction. Moreover, ML is water-soluble and potentially brain permeable, as well as regulates the formation and presence of free radicals. Overall, we demonstrate that a rational structure-based design strategy can generate a small molecule that can target and modulate multiple factors, providing a new tool to uncover and address AD complexity.
Collapse
Affiliation(s)
- Sanghyun Lee
- Life Sciences Institute, University of Michigan , Ann Arbor, Michigan 48109-2216, United States
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Savelieff MG, Liu Y, Senthamarai RRP, Korshavn KJ, Lee HJ, Ramamoorthy A, Lim MH. A small molecule that displays marked reactivity toward copper- versus zinc-amyloid-β implicated in Alzheimer's disease. Chem Commun (Camb) 2013; 50:5301-3. [PMID: 24326305 DOI: 10.1039/c3cc48473d] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Alzheimer's disease (AD) is a complex, multifactorial, neurodegenerative disease that poses tremendous difficulties in pinpointing its precise etiology. A toolkit, which specifically targets and modulates suggested key players, may elucidate their roles in disease onset and progression. We report high-resolution insights on the activity of a small molecule (L2-NO) which exhibits reactivity toward Cu(II)-amyloid-β (Aβ) over Zn(II)-Aβ.
Collapse
Affiliation(s)
- Masha G Savelieff
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | | | | | | | | | | | | |
Collapse
|
32
|
Liu Y, Kochi A, Pithadia AS, Lee S, Nam Y, Beck MW, He X, Lee D, Lim MH. Tuning Reactivity of Diphenylpropynone Derivatives with Metal-Associated Amyloid-β Species via Structural Modifications. Inorg Chem 2013; 52:8121-30. [DOI: 10.1021/ic400851w] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
| | | | | | | | - Younwoo Nam
- Department of Fine Chemistry, Seoul National University of Science and Technology, Seoul 139-743, Korea
| | | | | | - Dongkuk Lee
- Department of Fine Chemistry, Seoul National University of Science and Technology, Seoul 139-743, Korea
| | | |
Collapse
|
33
|
Soper MT, DeToma AS, Hyung SJ, Lim MH, Ruotolo BT. Amyloid-β-neuropeptide interactions assessed by ion mobility-mass spectrometry. Phys Chem Chem Phys 2013; 15:8952-61. [PMID: 23612608 PMCID: PMC3664942 DOI: 10.1039/c3cp50721a] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Recently, small peptides have been shown to modulate aggregation and toxicity of the amyloid-β protein (Aβ). As such, these new scaffolds may help discover a new class of biotherapeutics useful in the treatment of Alzheimer's disease. Many of these inhibitory peptide sequences have been derived from natural sources or from Aβ itself (e.g., C-terminal Aβ fragments). In addition, much earlier work indicates that tachykinins, a broad class of neuropeptides, display neurotrophic properties, presumably through direct interactions with either Aβ or its receptors. Based on this work, we undertook a limited screen of neuropeptides using ion mobility-mass spectrometry to search for similar such peptides with direct Aβ binding properties. Our results reveal that the neuropeptides leucine enkephalin (LE) and galanin interact with both the monomeric and small oligomeric forms of Aβ(1-40) to create a range of complexes having diverse stoichiometries, while some tachyknins (i.e., substance P) do not. LE interacts with Aβ more strongly than galanin, and we utilized ion mobility-mass spectrometry, molecular dynamics simulations, gel electrophoresis/Western blot, and transmission electron microscopy to study the influence of this peptide on the structure of Aβ monomer, small Aβ oligomers, as well as the eventual formation of Aβ fibrils. We find that LE binds selectively within a region of Aβ between its N-terminal tail and hydrophobic core. Furthermore, our data indicate that LE modulates fibril generation, producing shorter fibrillar aggregates when added in stoichiometric excess relative to Aβ.
Collapse
Affiliation(s)
- Molly T. Soper
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Alaina S. DeToma
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Suk-Joon Hyung
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Mi Hee Lim
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
- Life Science Institute, University of Michigan, Ann Arbor, MI 48109
| | | |
Collapse
|
34
|
Insights into antiamyloidogenic properties of the green tea extract (-)-epigallocatechin-3-gallate toward metal-associated amyloid-β species. Proc Natl Acad Sci U S A 2013; 110:3743-8. [PMID: 23426629 DOI: 10.1073/pnas.1220326110] [Citation(s) in RCA: 186] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Despite the significance of Alzheimer's disease, the link between metal-associated amyloid-β (metal-Aβ) and disease etiology remains unclear. To elucidate this relationship, chemical tools capable of specifically targeting and modulating metal-Aβ species are necessary, along with a fundamental understanding of their mechanism at the molecular level. Herein, we investigated and compared the interactions and reactivities of the green tea extract, (-)-epigallocatechin-3-gallate [(2R,3R)-5,7-dihydroxy-2-(3,4,5-trihydroxyphenyl)-3,4-dihydro-2H-1-benzopyran-3-yl 3,4,5-trihydroxybenzoate; EGCG], with metal [Cu(II) and Zn(II)]-Aβ and metal-free Aβ species. We found that EGCG interacted with metal-Aβ species and formed small, unstructured Aβ aggregates more noticeably than in metal-free conditions in vitro. In addition, upon incubation with EGCG, the toxicity presented by metal-free Aβ and metal-Aβ was mitigated in living cells. To understand this reactivity at the molecular level, structural insights were obtained by ion mobility-mass spectrometry (IM-MS), 2D NMR spectroscopy, and computational methods. These studies indicated that (i) EGCG was bound to Aβ monomers and dimers, generating more compact peptide conformations than those from EGCG-untreated Aβ species; and (ii) ternary EGCG-metal-Aβ complexes were produced. Thus, we demonstrate the distinct antiamyloidogenic reactivity of EGCG toward metal-Aβ species with a structure-based mechanism.
Collapse
|