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Mason AJ, Hurst I, Malik R, Siddique I, Solomonov I, Sagi I, Klärner FG, Schrader T, Bitan G. Different Inhibitors of Aβ42-Induced Toxicity Have Distinct Metal-Ion Dependency. ACS Chem Neurosci 2020; 11:2243-2255. [PMID: 32559370 DOI: 10.1021/acschemneuro.0c00192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Oligomers of amyloid β-protein (Aβ) are thought to be the proximal toxic agents initiating the neuropathologic process in Alzheimer's disease (AD). Therefore, targeting the self-assembly and oligomerization of Aβ has been an important strategy for designing AD therapeutics. In parallel, research into the metallobiology of AD has shown that Zn2+ can strongly modulate the aggregation of Aβ in vitro and both promote and inhibit the neurotoxicity of Aβ, depending on the experimental conditions. Thus, successful inhibitors of Aβ self-assembly may have to inhibit the toxicity not only of Aβ oligomers themselves but also of Aβ-Zn2+ complexes. However, there has been relatively little research investigating the effects of Aβ self-assembly and toxicity inhibitors in the presence of Zn2+. Our group has characterized previously a series of Aβ42 C-terminal fragments (CTFs), some of which have been shown to inhibit Aβ oligomerization and neurotoxicity. Here, we asked whether three CTFs shown to be potent inhibitors of Aβ42 toxicity maintained their activity in the presence of Zn2+. Biophysical analysis showed that the CTFs had different effects on oligomer, β-sheet, and fibril formation by Aβ42-Zn2+ complexes. However, cell viability experiments in differentiated PC-12 cells incubated with Aβ42-Zn2+ complexes in the absence or presence of these CTFs showed that the CTFs completely lost their inhibitory activity in the presence of Zn2+ even when applied at 10-fold excess relative to Aβ42. In light of these results, we tested another inhibitor, the molecular tweezer CLR01, which coincidentally had been shown to have a high affinity for Zn2+, suggesting that it could disrupt both Aβ42 oligomerization and Aβ42-Zn2+ complexation. Indeed, we found that CLR01 effectively inhibited the toxicity of Aβ42-Zn2+ complexes. Moreover, it did so at a lower concentration than needed for inhibiting the toxicity of Aβ42 alone. In agreement with these results, CLR01 inhibited β-sheet and fibril formation in Aβ42-Zn2+ complexes. Our data suggest that, for the development of efficient therapeutic agents, inhibitors of Aβ self-assembly and toxicity should be examined in the presence of relevant metal ions and that molecular tweezers may be particularly attractive candidates for therapy development.
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Affiliation(s)
- Ashley J. Mason
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, United States
| | - Ian Hurst
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, United States
| | - Ravinder Malik
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, United States
| | - Ibrar Siddique
- Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California 90095, United States
| | - Inna Solomonov
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Irit Sagi
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, 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, University of California at Los Angeles, Los Angeles, California 90095, United States
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Armiento V, Spanopoulou A, Kapurniotu A. Peptide-Based Molecular Strategies To Interfere with Protein Misfolding, Aggregation, and Cell Degeneration. Angew Chem Int Ed Engl 2020; 59:3372-3384. [PMID: 31529602 PMCID: PMC7064928 DOI: 10.1002/anie.201906908] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Indexed: 12/31/2022]
Abstract
Protein misfolding into amyloid fibrils is linked to more than 40 as yet incurable cell- and neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and type 2 diabetes. So far, however, only one of the numerous anti-amyloid molecules has reached patients. This Minireview gives an overview of molecular strategies and peptide chemistry "tools" to design, develop, and discover peptide-based molecules as anti-amyloid drug candidates. We focus on two major inhibitor rational design strategies: 1) the oldest and most common strategy, based on molecular recognition elements of amyloid self-assembly, and 2) a more recent approach, based on cross-amyloid interactions. We discuss why peptide-based amyloid inhibitors, in particular their advanced generations, can be promising leads or candidates for anti-amyloid drugs as well as valuable tools for deciphering amyloid-mediated cell damage and its link to disease pathogenesis.
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Affiliation(s)
- Valentina Armiento
- Division of Peptide BiochemistryTUM School of Life SciencesTechnische Universität MünchenEmil-Erlenmeyer-Forum 585354FreisingGermany
| | - Anna Spanopoulou
- Division of Peptide BiochemistryTUM School of Life SciencesTechnische Universität MünchenEmil-Erlenmeyer-Forum 585354FreisingGermany
- Current address: Coriolis Pharma Research GmbHFraunhoferstrasse 18B82152PlaneggGermany
| | - Aphrodite Kapurniotu
- Division of Peptide BiochemistryTUM School of Life SciencesTechnische Universität MünchenEmil-Erlenmeyer-Forum 585354FreisingGermany
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Armiento V, Spanopoulou A, Kapurniotu A. Peptid‐basierte molekulare Strategien zum Einsatz bei Proteinfehlfaltung, Proteinaggregation und Zelldegeneration. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201906908] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Valentina Armiento
- Fachgebiet PeptidbiochemieTUM School of Life SciencesTechnische Universität München Emil-Erlenmeyer-Forum 5 85354 Freising Deutschland
| | - Anna Spanopoulou
- Fachgebiet PeptidbiochemieTUM School of Life SciencesTechnische Universität München Emil-Erlenmeyer-Forum 5 85354 Freising Deutschland
- Aktuelle Adresse: Coriolis Pharma Research GmbH Fraunhoferstraße 18B 82152 Planegg Deutschland
| | - Aphrodite Kapurniotu
- Fachgebiet PeptidbiochemieTUM School of Life SciencesTechnische Universität München Emil-Erlenmeyer-Forum 5 85354 Freising Deutschland
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Li H, Rahimi F, Bitan G. Modulation of Amyloid β-Protein (Aβ) Assembly by Homologous C-Terminal Fragments as a Strategy for Inhibiting Aβ Toxicity. ACS Chem Neurosci 2016; 7:845-56. [PMID: 27322435 DOI: 10.1021/acschemneuro.6b00154] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Self-assembly of amyloid β-protein (Aβ) into neurotoxic oligomers and fibrillar aggregates is a key process thought to be the proximal event leading to development of Alzheimer's disease (AD). Therefore, numerous attempts have been made to develop reagents that disrupt this process and prevent the formation of the toxic oligomers and aggregates. An attractive strategy for developing such reagents is to use peptides derived from Aβ based on the assumption that such peptides would bind to full-length Aβ, interfere with binding of additional full-length molecules, and thereby prevent formation of the toxic species. Guided by this rationale, most of the studies in the last two decades have focused on preventing formation of the core cross-β structure of Aβ amyloid fibrils using β-sheet-breaker peptides derived from the central hydrophobic cluster of Aβ. Though this approach is effective in inhibiting fibril formation, it is generally inefficient in preventing Aβ oligomerization. An alternative approach is to use peptides derived from the C-terminus of Aβ, which mediates both oligomerization and fibrillogenesis. This approach has been explored by several groups, including our own, and led to the discovery of several lead peptides with moderate to high inhibitory activity. Interestingly, the mechanisms of these inhibitory effects have been found to be diverse, and only in a small percentage of cases involved interference with β-sheet formation. Here, we review the strategy of using C-terminal fragments of Aβ as modulators of Aβ assembly and discuss the relevant challenges, therapeutic potential, and mechanisms of action of such fragments.
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Affiliation(s)
- Huiyuan Li
- West Virginia University, Morgantown, West Virginia 26506, United States
| | - Farid Rahimi
- Biomedical
Science and Biochemistry, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Gal Bitan
- Department
of Neurology, David Geffen School of Medicine, Brain Research Institute,
and Molecular Biology Institute, University of California at Los Angeles, Neuroscience Research Building 1, Room 451 635 Charles E. Young Drive
South, Los Angeles, California 90095-7334, United States
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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.
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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
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Synthetic and structural routes for the rational conversion of peptides into small molecules. Methods Mol Biol 2015; 1268:159-93. [PMID: 25555725 DOI: 10.1007/978-1-4939-2285-7_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The demand for modified peptides with improved stability profiles and pharmacokinetic properties is driving extensive research effort in this field. The conversion of peptides into organic molecules, as traditional drugs, is a long and puzzled way. Many and versatile approaches have been described for designing peptide mimetics: the substitution of natural residues with modified amino acids and the rigidification and modification of the backbone are the main structural and chemical routes walked in medicinal chemistry. All of these strategies have been successfully applied to obtain active new compounds in molecular biology, drug discovery and design. Here we propose a panoramic review of the most common methods for the preparation of modified peptides and the most interesting findings of the last decade.
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Fu Z, Aucoin D, Ahmed M, Ziliox M, Van Nostrand WE, Smith SO. Capping of aβ42 oligomers by small molecule inhibitors. Biochemistry 2014; 53:7893-903. [PMID: 25422864 PMCID: PMC4278677 DOI: 10.1021/bi500910b] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Aβ42 peptides associate into soluble oligomers and protofibrils in the process of forming the amyloid fibrils associated with Alzheimer's disease. The oligomers have been reported to be more toxic to neurons than fibrils, and have been targeted by a wide range of small molecule and peptide inhibitors. With single touch atomic force microscopy (AFM), we show that monomeric Aβ42 forms two distinct types of oligomers, low molecular weight (MW) oligomers with heights of 1-2 nm and high MW oligomers with heights of 3-5 nm. In both cases, the oligomers are disc-shaped with diameters of ~10-15 nm. The similar diameters suggest that the low MW species stack to form the high MW oligomers. The ability of Aβ42 inhibitors to interact with these oligomers is probed using atomic force microscopy and NMR spectroscopy. We show that curcumin and resveratrol bind to the N-terminus (residues 5-20) of Aβ42 monomers and cap the height of the oligomers that are formed at 1-2 nm. A second class of inhibitors, which includes sulindac sulfide and indomethacin, exhibit very weak interactions across the Aβ42 sequence and do not block the formation of the high MW oligomers. The correlation between N-terminal interactions and capping of the height of the Aβ oligomers provides insights into the mechanism of inhibition and the pathway of Aβ aggregation.
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Affiliation(s)
- Ziao Fu
- Department of Biochemistry and Cell Biology, Stony Brook University , Stony Brook, New York 11794-5215, United States
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