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Song C, Zhang T, Zhang Y. Conformational Essentials Responsible for Neurotoxicity of Aβ42 Aggregates Revealed by Antibodies against Oligomeric Aβ42. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27196751. [PMID: 36235284 PMCID: PMC9570743 DOI: 10.3390/molecules27196751] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/16/2022]
Abstract
Soluble aggregation of amyloid β-peptide 1-42 (Aβ42) and deposition of Aβ42 aggregates are the initial pathological hallmarks of Alzheimer's disease (AD). The bipolar nature of Aβ42 molecule results in its ability to assemble into distinct oligomers and higher aggregates, which may drive some of the phenotypic heterogeneity observed in AD. Agents targeting Aβ42 or its aggregates, such as anti-Aβ42 antibodies, can inhibit the aggregation of Aβ42 and toxicity of Aβ42 aggregates to neural cells to a certain extent. However, the epitope specificity of an antibody affects its binding affinity for different Aβ42 species. Different antibodies target different sites on Aβ42 and thus elicit different neuroprotective or cytoprotective effects. In the present review, we summarize significant information reflected by anti-Aβ42 antibodies in different immunotherapies and propose an overview of the structure (conformation)-toxicity relationship of Aβ42 aggregates. This review aimed to provide a reference for the directional design of antibodies against the most pathogenic conformation of Aβ42 aggregates.
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Affiliation(s)
- Chuli Song
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun 130012, China
| | - Tianyu Zhang
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun 130012, China
| | - Yingjiu Zhang
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun 130012, China
- School of Life Science, Jilin University, Changchun 130012, China
- Correspondence:
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Zhang X, Huai Y, Cai J, Song C, Zhang Y. Novel antibody against oligomeric amyloid-β: Insight into factors for effectively reducing the aggregation and cytotoxicity of amyloid-β aggregates. Int Immunopharmacol 2018; 67:176-185. [PMID: 30553911 DOI: 10.1016/j.intimp.2018.12.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/06/2018] [Accepted: 12/05/2018] [Indexed: 12/27/2022]
Abstract
Amyloid-beta 42 (Aβ42) aggregates represent a prominent histopathological feature in Alzheimer's disease (AD); thus, immunotherapy against oligomeric Aβ42 aggregates is considered to be a potentially safe and specific therapeutic strategy. In this study, we identified an anti-oligomeric Aβ42 aggregate single-chain variable fragment (scFv) antibody, HT6, that is capable of efficiently binding to medium-sized Aβ42 aggregates (mainly 18-45 kDa) in vitro with an equilibrium dissociation constant (KD) of 3.0 × 10-6 M, whether they were derived from Aβ42 monomer, larger Aβ42 oligomers, or even fibrils. This ability allowed scFv HT6 to induce the gradual disassembly of large Aβ42 aggregates into small Aβ42 oligomers while simultaneously effectively inhibiting the further development of Aβ42 aggregates. Moreover, the scFv HT6-targeted conformational region on Aβ42 aggregates was found to be more local and relatively close to the N-terminus of Aβ42; thus, scFv HT6 significantly delayed or even prevented the aggregation of Aβ42 protofibrils, while significantly reducing the cytotoxicity of Aβ42 oligomers. Overall, this study demonstrate that even though the decrease in the cytotoxicity of Aβ42 aggregates might be closely related to the reduction in Aβ42 aggregates and vice versa, the reduction in Aβ42 aggregates might not necessarily be accompanied by or followed by the reduction or even elimination of the cytotoxicity of Aβ42 aggregates. This insight enriches the diversity of anti-oligomeric Aβ42 antibodies, further providing a new understanding into the relationship between their binding pattern to Aβ42 aggregates and the efficacy against their formation, offering a therapeutic strategy to delay the progression of AD.
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Affiliation(s)
- Xiaoning Zhang
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun, China
| | - Yangyang Huai
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun, China
| | - Jing Cai
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun, China; China-Japan Union Hospital of Jilin University, Changchun, China
| | - Chuli Song
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun, China
| | - Yingjiu Zhang
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, Changchun, China; School of Life Science, Jilin University, Changchun, China.
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Zhang Y, Huai Y, Zhang X, Song C, Cai J, Zhang Y. The Mode of Action of an Anti-Oligomeric Amyloid β-Protein Antibody Affects its Protective Efficacy. Neurotox Res 2018; 35:304-317. [PMID: 30229545 DOI: 10.1007/s12640-018-9955-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 09/06/2018] [Accepted: 09/07/2018] [Indexed: 12/22/2022]
Abstract
The process of developing antibody drugs for Alzheimer's disease therapy has been both long and difficult; however, recent advances suggest that antibodies against neurotoxic Αβ42 can suppress the progression of AD, especially on its early stage. Here, we obtained and characterized a novel anti-oligomeric Aβ42 aggregate scFv antibody, HT7, which could induce the significant disaggregation of Aβ42 aggregates through the release of stable and non-cytotoxic hexameric complexes that were composed of three scFv HT7s and one Aβ42 trimer, the latter being found to serve as the assembled subunit within larger Aβ42 aggregates in addition to existing freely between the cells. The docking model of the scFv HT7-Aβ42 complex revealed that only the N-terminal peptide of the Aβ42 molecule was bound into the groove between the VH and VL domains of scFv HT7. Thus, it was suggested that the hydrophobic interaction between the C-terminal peptides of Aβ42 molecules maintained the stability of the Aβ42 trimers or the Aβ42 trimer subunits. The saturation of Aβ42 trimer subunits by scFv HT7 and the subsequent dissociation of the scFv HT7-saturated Aβ42 trimer subunits from larger Aβ42 aggregates constituted the primary mechanisms underlying the high efficacy of scFv HT7. Our findings revealed that it was not sufficient for an anti-oligomeric Aβ42 antibody to exhibit high specificity and high affinity to the oligomeric Aβ42 aggregates in order to promote Aβ42 aggregate clearance and neutralize their cytotoxic effects. Here, for the first time, we proposed a "post-saturation dissociation" mechanism of Aβ42 oligomeric subunits for effective anti-Aβ42 antibodies.
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Affiliation(s)
- Yunlong Zhang
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, 2699 Qian-Jin Street, Changchun, 130012, Jilin, China
| | - Yangyang Huai
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, 2699 Qian-Jin Street, Changchun, 130012, Jilin, China
| | - Xiaoning Zhang
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, 2699 Qian-Jin Street, Changchun, 130012, Jilin, China
| | - Chuli Song
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, 2699 Qian-Jin Street, Changchun, 130012, Jilin, China
| | - Jing Cai
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, 2699 Qian-Jin Street, Changchun, 130012, Jilin, China.,China-Japan Union Hospital of Jilin University, Changchun, China
| | - Yingjiu Zhang
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, Jilin University, 2699 Qian-Jin Street, Changchun, 130012, Jilin, China. .,School of Life Science, Jilin University, Changchun, China.
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The protective effects and underlying mechanism of an anti-oligomeric Aβ42 single-chain variable fragment antibody. Neuropharmacology 2015; 99:387-95. [PMID: 26256421 DOI: 10.1016/j.neuropharm.2015.07.038] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 07/21/2015] [Accepted: 07/31/2015] [Indexed: 01/17/2023]
Abstract
Oligomeric Aβ42 aggregates have been identified as one of the major neurotoxic components of Alzheimer's disease (AD). Immunotherapy targeted against these Aβ42 aggregates has been proposed as an appropriate therapeutic approach for the treatment of AD. Here, we report an anti-oligomeric Aβ42 single-chain variable fragment (scFv) antibody, named MO6, obtained from the human antibody library of a healthy donor. ScFv MO6 specifically recognized and bound to the oligomeric Aβ42 (Aβ42 oligomers and immature protofibrils; 18-37 kDa), and reduced their levels mainly by blocking their formation, although scFv MO6 also induced disaggregation of Aβ42 aggregates. More importantly, scFv MO6 ameliorated or attenuated Aβ42-induced cytotoxicity and increased cell viability by up to 33%. Furthermore, scFv MO6 efficiently passed through an in vitro blood-brain barrier (BBB) model with a delivery efficiency of 66% after 60 min post-administration. ScFv MO6 is a monovalent antibody with an affinity constant (KD) of 5.2×10(-6) M for Aβ42 oligomers. Molecular docking simulations of Aβ42 to scFv MO6 revealed that the approach and specific binding of scFv MO6 to oligomeric Aβ42 aggregates was achieved by conformational recognition and directed induction, which resulted in a more dynamic adaptation of Aβ42 to scFv MO6, occurring mainly in the N-terminal (3-4), middle (12-19) and C-terminal (34-42) regions of Aβ42. This binding mode of scFv MO6 to Aβ42 explains its protective effects against oligomeric Aβ42. Our findings may be applied for the design of a smaller antibody specific for Aβ42 oligermers.
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Zhang Y, Sun Y, Huai Y, Zhang YJ. Functional Characteristics and Molecular Mechanism of a New scFv Antibody Against Aβ42 Oligomers and Immature Protofibrils. Mol Neurobiol 2014; 52:1269-1281. [DOI: 10.1007/s12035-014-8910-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Accepted: 09/28/2014] [Indexed: 11/30/2022]
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Guo W, Sha S, Jiang T, Xing X, Cao Y. A new DNA vaccine fused with the C3d-p28 induces a Th2 immune response against amyloid-beta. Neural Regen Res 2014; 8:2581-90. [PMID: 25206569 PMCID: PMC4145937 DOI: 10.3969/j.issn.1673-5374.2013.27.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Accepted: 08/02/2013] [Indexed: 01/11/2023] Open
Abstract
To enhance anti-amyloid-beta (Aβ) antibody generation and induce a Th2 immune response, we constructed a new DNA vaccine p(Aβ3–10)10-C3d-p28.3 encoding ten repeats of Aβ3–10 and three copies of C3d-p28 as a molecular adjuvant. In this study, we administered this adjuvant cularly to female C57BL/6J mice at 8–10 weeks of age. Enzyme linked immunosorbent assay was used to detect the titer of serum anti-Aβ antibody, isotypes, and cytokines in splenic T cells. A 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was used to detect the prolifera-tion rate of splenic T cells. Brain sections from a 12-month-old APP/PS1 transgenic mouse were used for detecting the binding capacities of anti-Aβ antibodies to Aβ plaques. The p(Aβ3–10)10-C3d-p28.3 vaccine induced high titers of anti-amyloid-β antibodies, which bound to Aβ plaques in APP/PS1 transgenic mouse brain tissue, demonstrating that the vaccine is effective against plaques in a mouse model of Alzheimer's disease. Moreover, the vaccine elicited a predo-minantly IgG1 humoral response and low levels of interferon-γ in ex vivo cultured splenocytes, dicating that the vaccine could shift the cellular immune response towards a Th2 phenotype. This indicated that the vaccine did not elicit a detrimental immune response and had a favorable safety profile. Our results indicate that the p(Aβ3–10)10-C3d-p28.3 vaccine is a promising immunothe-peutic option for Aβ vaccination in Alzheimer's disease.
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Affiliation(s)
- Wanshu Guo
- Department of Neurology, First Affiliated Hospital of China Medical University, Shenyang 110001, Liaoning Province, China
| | - Sha Sha
- Department of Neurology, First Affiliated Hospital of China Medical University, Shenyang 110001, Liaoning Province, China
| | - Tongzi Jiang
- Department of Neurology, First People's Hospital of Shenyang City, Shenyang 110041, Liaoning Province, China
| | - Xiaona Xing
- Department of Neurology, First Affiliated Hospital of China Medical University, Shenyang 110001, Liaoning Province, China
| | - Yunpeng Cao
- Department of Neurology, First Affiliated Hospital of China Medical University, Shenyang 110001, Liaoning Province, China
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