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Neațu M, Covaliu A, Ioniță I, Jugurt A, Davidescu EI, Popescu BO. Monoclonal Antibody Therapy in Alzheimer's Disease. Pharmaceutics 2023; 16:60. [PMID: 38258071 DOI: 10.3390/pharmaceutics16010060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/22/2023] [Accepted: 12/28/2023] [Indexed: 01/24/2024] Open
Abstract
Alzheimer's disease is a neurodegenerative condition marked by the progressive deterioration of cognitive abilities, memory impairment, and the accumulation of abnormal proteins, specifically beta-amyloid plaques and tau tangles, within the brain. Despite extensive research efforts, Alzheimer's disease remains without a cure, presenting a significant global healthcare challenge. Recently, there has been an increased focus on antibody-based treatments as a potentially effective method for dealing with Alzheimer's disease. This paper offers a comprehensive overview of the current status of research on antibody-based molecules as therapies for Alzheimer's disease. We will briefly mention their mechanisms of action, therapeutic efficacy, and safety profiles while addressing the challenges and limitations encountered during their development. We also highlight some crucial considerations in antibody-based treatment development, including patient selection criteria, dosing regimens, or safety concerns. In conclusion, antibody-based therapies present a hopeful outlook for addressing Alzheimer's disease. While challenges remain, the accumulating evidence suggests that these therapies may offer substantial promise in ameliorating or preventing the progression of this debilitating condition, thus potentially enhancing the quality of life for the millions of individuals and families affected by Alzheimer's disease worldwide.
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Affiliation(s)
- Monica Neațu
- Department of Clinical Neurosciences, "Carol Davila" University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Neurology, Colentina Clinical Hospital, 020125 Bucharest, Romania
| | - Anca Covaliu
- Department of Clinical Neurosciences, "Carol Davila" University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Neurology, Colentina Clinical Hospital, 020125 Bucharest, Romania
| | - Iulia Ioniță
- Department of Clinical Neurosciences, "Carol Davila" University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Neurology, Colentina Clinical Hospital, 020125 Bucharest, Romania
| | - Ana Jugurt
- Department of Clinical Neurosciences, "Carol Davila" University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Neurology, Colentina Clinical Hospital, 020125 Bucharest, Romania
| | - Eugenia Irene Davidescu
- Department of Clinical Neurosciences, "Carol Davila" University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Neurology, Colentina Clinical Hospital, 020125 Bucharest, Romania
| | - Bogdan Ovidiu Popescu
- Department of Clinical Neurosciences, "Carol Davila" University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Neurology, Colentina Clinical Hospital, 020125 Bucharest, Romania
- Department of Cell Biology, Neurosciences and Experimental Myology, "Victor Babeș" National Institute of Pathology, 050096 Bucharest, Romania
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Faresjö R, Sehlin D, Syvänen S. Age, dose, and binding to TfR on blood cells influence brain delivery of a TfR-transported antibody. Fluids Barriers CNS 2023; 20:34. [PMID: 37170266 PMCID: PMC10173660 DOI: 10.1186/s12987-023-00435-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 04/27/2023] [Indexed: 05/13/2023] Open
Abstract
BACKGROUND Transferrin receptor 1 (TfR1) mediated brain delivery of antibodies could become important for increasing the efficacy of emerging immunotherapies in Alzheimer's disease (AD). However, age, dose, binding to TfR1 on blood cells, and pathology could influence the TfR1-mediated transcytosis of TfR1-binders across the blood-brain barrier (BBB). The aim of the study was, therefore, to investigate the impact of these factors on the brain delivery of a bispecific TfR1-transported Aβ-antibody, mAb3D6-scFv8D3, in comparison with the conventional antibody mAb3D6. METHODS Young (3-5 months) and aged (17-20 months) WT and tg-ArcSwe mice (AD model) were injected with 125I-labeled mAb3D6-scFv8D3 or mAb3D6. Three different doses were used in the study, 0.05 mg/kg (low dose), 1 mg/kg (high dose), and 10 mg/kg (therapeutic dose), with equimolar doses for mAb3D6. The dose-corrected antibody concentrations in whole blood, blood cells, plasma, spleen, and brain were evaluated at 2 h post-administration. Furthermore, isolated brains were studied by autoradiography, nuclear track emulsion, and capillary depletion to investigate the intrabrain distribution of the antibodies, while binding to blood cells was studied in vitro using blood isolated from young and aged mice. RESULTS The aged WT and tg-ArcSwe mice showed significantly lower brain concentrations of TfR-binding [125I]mAb3D6-scFv8D3 and higher concentrations in the blood cell fraction compared to young mice. For [125I]mAb3D6, no significant differences in blood or brain delivery were observed between young and aged mice or between genotypes. A low dose of [125I]mAb3D6-scFv8D3 was associated with increased relative parenchymal delivery, as well as increased blood cell distribution. Brain concentrations and relative parenchymal distribution of [125I]mAb3D6-scFv8D6 did not differ between tg-ArcSwe and WT mice at this early time point but were considerably increased compared to those observed for [125I]mAb3D6. CONCLUSION Age-dependent differences in blood and brain concentrations were observed for the bispecific antibody mAb3D6-scFv8D3 but not for the conventional Aβ antibody mAb3D6, indicating an age-related effect on TfR1-mediated brain delivery. The lowest dose of [125I]mAb3D6-scFv8D3 was associated with higher relative BBB penetration but, at the same time, a higher distribution to blood cells. Overall, Aβ-pathology did not influence the early brain distribution of the bispecific antibody. In summary, age and bispecific antibody dose were important factors determining brain delivery, while genotype was not.
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Affiliation(s)
- Rebecca Faresjö
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden.
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Rofo F, Meier SR, Metzendorf NG, Morrison JI, Petrovic A, Syvänen S, Sehlin D, Hultqvist G. A Brain-Targeting Bispecific-Multivalent Antibody Clears Soluble Amyloid-Beta Aggregates in Alzheimer's Disease Mice. Neurotherapeutics 2022; 19:1588-1602. [PMID: 35939261 PMCID: PMC9606191 DOI: 10.1007/s13311-022-01283-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2022] [Indexed: 12/04/2022] Open
Abstract
Amyloid-β (Aβ) oligomers and protofibrils are suggested to be the most neurotoxic Aβ species in Alzheimer's disease (AD). Hence, antibodies with strong and selective binding to these soluble Aβ aggregates are of therapeutic potential. We have recently introduced HexaRmAb158, a multivalent antibody with additional Aβ-binding sites in the form of single-chain fragment variables (scFv) on the N-terminal ends of Aβ protofibril selective antibody (RmAb158). Due to the additional binding sites and the short distance between them, HexaRmAb158 displayed a slow dissociation from protofibrils and strong binding to oligomers in vitro. In the current study, we aimed at investigating the therapeutic potential of this antibody format in vivo using mouse models of AD. To enhance BBB delivery, the transferrin receptor (TfR) binding moiety (scFv8D3) was added, forming the bispecific-multivalent antibody (HexaRmAb158-scFv8D3). The new antibody displayed a weaker TfR binding compared to the previously developed RmAb158-scFv8D3 and was less efficiently transcytosed in a cell-based BBB model. HexaRmAb158 detected soluble Aβ aggregates derived from brains of tg-ArcSwe and AppNL-G-F mice more efficiently compared to RmAb158. When intravenously injected, HexaRmAb158-scFv8D3 was actively transported over the BBB into the brain in vivo. Brain uptake was marginally lower than that of RmAb158-scFv8D3, but significantly higher than observed for conventional IgG antibodies. Both antibody formats displayed similar brain retention (72 h post injection) and equal capacity in clearing soluble Aβ aggregates in tg-ArcSwe mice. In conclusion, we demonstrate a bispecific-multivalent antibody format capable of passing the BBB and targeting a wide-range of sizes of soluble Aβ aggregates.
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Affiliation(s)
- Fadi Rofo
- Department of Pharmacy, Uppsala University, 75124, Uppsala, Sweden
| | - Silvio R Meier
- Department of Public Health and Caring Sciences, Uppsala University, 75185, Uppsala, Sweden
| | | | - Jamie I Morrison
- Department of Pharmacy, Uppsala University, 75124, Uppsala, Sweden
| | - Alex Petrovic
- Department of Pharmacy, Uppsala University, 75124, Uppsala, Sweden
| | - Stina Syvänen
- Department of Public Health and Caring Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Dag Sehlin
- Department of Public Health and Caring Sciences, Uppsala University, 75185, Uppsala, Sweden
| | - Greta Hultqvist
- Department of Pharmacy, Uppsala University, 75124, Uppsala, Sweden.
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Santoro A, Grimaldi M, Buonocore M, Stillitano I, Gloria A, Santin M, Bobba F, Sublimi Saponetti M, Ciaglia E, D'Ursi AM. New Aβ(1-42) ligands from anti-amyloid antibodies: Design, synthesis, and structural interaction. Eur J Med Chem 2022; 237:114400. [PMID: 35489223 DOI: 10.1016/j.ejmech.2022.114400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 03/17/2022] [Accepted: 04/15/2022] [Indexed: 11/18/2022]
Abstract
Alzheimer's disease (AD), is the most common neurodegenerative disorder of the aging population resulting in progressive cognitive and functional decline. Accumulation of amyloid plaques around neuronal cells is considered a critical pathogenetic event and, in most cases, a hallmark of the pathology. In the attempt to identify anti-AD drug candidates, hundreds of molecules targeting Aβ peptides have been screened. Peptide molecules have been widely explored, appreciating chemical stability, biocompatibility, and low production cost. More recently, many anti-Aβ(1-42) monoclonal antibodies have been developed, given the excellent potential of immunotherapy for treating or preventing AD. Antibodies are versatile ligands that bind a large variety of molecules with high affinity and specificity; however, their extensive therapeutic application is complex and requires huge economic investments. Novel approaches to identify alternative antibody formats are considered with great interest. In this context, taking advantage of the favorable peptide properties and the availability of Aβ-antibodies structural data, we followed an innovative research approach to identify short peptide sequences on the model of the binding sites of Aβ(1-42)/antibodies. WAibH and SYSTPGK were designed as mimics of solanezumab and aducanumab, respectively. Circular dichroism and nuclear magnetic resonance analysis reveal that the antibody-derived peptides interact with Aβ(1-42) in the soluble monomeric form. Moreover, AFM microscopy imaging shows that WAibH and SYSTPGK are capable of controlling the Aβ(1-42) aggregation. The strategy to identify WAibH and SYSTPGK is innovative and can be widely applied for new anti-Aβ antibody mimicking peptides.
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Affiliation(s)
- Angelo Santoro
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132 - 84084, Fisciano, Salerno, Italy
| | - Manuela Grimaldi
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132 - 84084, Fisciano, Salerno, Italy
| | - Michela Buonocore
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132 - 84084, Fisciano, Salerno, Italy
| | - Ilaria Stillitano
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132 - 84084, Fisciano, Salerno, Italy
| | - Antonio Gloria
- Institute of Polymers, Composites and Biomaterials, National Research Council of Italy, V.le J.F. Kennedy 54 - Pad. 20, Mostra d'Oltremare, 80125, Naples, Italy
| | - Matteo Santin
- Centre for Regenerative Medicine and Devices, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, BN2 4GJ, UK
| | - Fabrizio Bobba
- Department of Physics, University of Salerno, Via Giovanni Paolo II, 132 - 84084, Fisciano, Salerno, Italy
| | - Matilde Sublimi Saponetti
- Department of Physics, University of Salerno, Via Giovanni Paolo II, 132 - 84084, Fisciano, Salerno, Italy
| | - Elena Ciaglia
- Department of Medicine, Surgery and Dentistry Scuola Medica Salernitana, University of Salerno, Via Salvatore Allende, 84081, Baronissi, Salerno, Italy
| | - Anna Maria D'Ursi
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 132 - 84084, Fisciano, Salerno, Italy.
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Stern AM, Liu L, Jin S, Liu W, Meunier AL, Ericsson M, Miller MB, Batson M, Sun T, Kathuria S, Reczek D, Pradier L, Selkoe DJ. OUP accepted manuscript. Brain 2022; 145:2528-2540. [PMID: 35084489 PMCID: PMC9337809 DOI: 10.1093/brain/awac023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 12/01/2021] [Accepted: 12/20/2021] [Indexed: 11/26/2022] Open
Abstract
Aqueously soluble oligomers of amyloid-β peptide may be the principal neurotoxic forms of amyloid-β in Alzheimer’s disease, initiating downstream events that include tau hyperphosphorylation, neuritic/synaptic injury, microgliosis and neuron loss. Synthetic oligomeric amyloid-β has been studied extensively, but little is known about the biochemistry of natural oligomeric amyloid-β in human brain, even though it is more potent than simple synthetic peptides and comprises truncated and modified amyloid-β monomers. We hypothesized that monoclonal antibodies specific to neurotoxic oligomeric amyloid-β could be used to isolate it for further study. Here we report a unique human monoclonal antibody (B24) raised against synthetic oligomeric amyloid-β that potently prevents Alzheimer’s disease brain oligomeric amyloid-β-induced impairment of hippocampal long-term potentiation. B24 binds natural and synthetic oligomeric amyloid-β and a subset of amyloid plaques, but only in the presence of Ca2+. The amyloid-β N terminus is required for B24 binding. Hydroxyapatite chromatography revealed that natural oligomeric amyloid-β is highly avid for Ca2+. We took advantage of the reversible Ca2+-dependence of B24 binding to perform non-denaturing immunoaffinity isolation of oligomeric amyloid-β from Alzheimer’s disease brain-soluble extracts. Unexpectedly, the immunopurified material contained amyloid fibrils visualized by electron microscopy and amenable to further structural characterization. B24-purified human oligomeric amyloid-β inhibited mouse hippocampal long-term potentiation. These findings identify a calcium-dependent method for purifying bioactive brain oligomeric amyloid-β, at least some of which appears fibrillar.
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Affiliation(s)
- Andrew M Stern
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women’s Hospital, 60 Fenwood Road Rm 10002Q, Boston, MA 02115, USA
| | - Lei Liu
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women’s Hospital, 60 Fenwood Road Rm 10002Q, Boston, MA 02115, USA
| | - Shanxue Jin
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women’s Hospital, 60 Fenwood Road Rm 10002Q, Boston, MA 02115, USA
| | - Wen Liu
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women’s Hospital, 60 Fenwood Road Rm 10002Q, Boston, MA 02115, USA
| | - Angela L Meunier
- Ann Romney Center for Neurologic Diseases, Department of Neurology, Brigham and Women’s Hospital, 60 Fenwood Road Rm 10002Q, Boston, MA 02115, USA
| | - Maria Ericsson
- Harvard Medical School Electron Microscopy Facility, Goldenson Building 323, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Michael B Miller
- Division of Neuropathology, Department of Pathology, Brigham and Women’s Hospital, 75 Francis St, Boston, MA 02115, USA
| | - Megan Batson
- Sanofi Corporation, 49 New York Avenue, Framingham, MA 01701, USA
| | - Tingwan Sun
- Sanofi Corporation, 49 New York Avenue, Framingham, MA 01701, USA
| | - Sagar Kathuria
- Sanofi Corporation, 49 New York Avenue, Framingham, MA 01701, USA
| | - David Reczek
- Sanofi Corporation, 49 New York Avenue, Framingham, MA 01701, USA
| | - Laurent Pradier
- Sanofi Corporation, 49 New York Avenue, Framingham, MA 01701, USA
| | - Dennis J Selkoe
- Correspondence to: Dennis J. Selkoe Ann Romney Center for Neurologic Diseases Department of Neurology, Brigham and Women’s Hospital 60 Fenwood Road Rm 10002Q Boston, MA 02115, USA E-mail:
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Hermans SJ, Nero TL, Morton CJ, Gooi JH, Crespi GAN, Hancock NC, Gao C, Ishii K, Markulić J, Parker MW. Structural biology of cell surface receptors implicated in Alzheimer’s disease. Biophys Rev 2021; 14:233-255. [DOI: 10.1007/s12551-021-00903-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 11/02/2021] [Indexed: 02/06/2023] Open
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Pao PJ, Hsu MF, Chiang MH, Chen CT, Lee CC, Wang AHJ. Structural basis of an epitope tagging system derived from Haloarcula marismortui bacteriorhodopsin I D94N and its monoclonal antibody GD-26. FEBS J 2021; 289:730-747. [PMID: 34499806 PMCID: PMC9292375 DOI: 10.1111/febs.16184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 07/12/2021] [Accepted: 09/06/2021] [Indexed: 02/05/2023]
Abstract
Specific antibody interactions with short peptides have made epitope tagging systems a vital tool employed in virtually all fields of biological research. Here, we present a novel epitope tagging system comprised of a monoclonal antibody named GD‐26, which recognises the TD peptide (GTGATPADD) derived from Haloarcula marismortui bacteriorhodopsin I (HmBRI) D94N mutant. The crystal structure of the antigen‐binding fragment (Fab) of GD‐26 complexed with the TD peptide was determined to a resolution of 1.45 Å. The TD peptide was found to adopt a 310 helix conformation within the binding cleft, providing a characteristic peptide structure for recognition by GD‐26 Fab. Based on the structure information, polar and nonpolar forces collectively contribute to the strong binding. Attempts to engineer the TD peptide show that the proline residue is crucial for the formation of the 310 helix in order to fit into the binding cleft. Isothermal calorimetry (ITC) reported a dissociation constant KD of 12 ± 2.8 nm, indicating a strong interaction between the TD peptide and GD‐26 Fab. High specificity of GD‐26 IgG to the TD peptide was demonstrated by western blotting, ELISA and immunofluorescence as only TD‐tagged proteins were detected, suggesting the effectiveness of the GD‐26/TD peptide tagging system. In addition to already‐existing epitope tags such as the FLAG tag and the ALFA tag adopting either extended or α‐helix conformations, the unique 310 helix conformation of the TD peptide together with the corresponding monoclonal antibody GD‐26 offers a novel tagging option for research.
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Affiliation(s)
- Po-Jung Pao
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Min-Feng Hsu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Ming-Hui Chiang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chun-Ting Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Cheng-Chung Lee
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Andrew H-J Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
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Yang T, Dang Y, Ostaszewski B, Mengel D, Steffen V, Rabe C, Bittner T, Walsh DM, Selkoe DJ. Target engagement in an alzheimer trial: Crenezumab lowers amyloid β oligomers in cerebrospinal fluid. Ann Neurol 2019; 86:215-224. [PMID: 31168802 PMCID: PMC6771589 DOI: 10.1002/ana.25513] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 05/29/2019] [Accepted: 05/29/2019] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Oligomeric forms of amyloid β protein (oAβ) are believed to be principally responsible for neurotoxicity in Alzheimer disease (AD), but it is not known whether anti-Aβ antibodies are capable of lowering oAβ levels in humans. METHODS We developed an ultrasensitive immunoassay and used it to measure oAβ in cerebrospinal fluid (CSF) from 104 AD subjects participating in the ABBY and BLAZE phase 2 trials of the anti-Aβ antibody crenezumab. Patients received subcutaneous (SC) crenezumab (300mg) or placebo every 2 weeks, or intravenous (IV) crenezumab (15mg/kg) or placebo every 4 weeks for 68 weeks. Ninety-eight of the 104 patients had measurable baseline oAβ levels, and these were compared to levels at week 69 in placebo (n = 28), SC (n = 35), and IV (n = 35) treated patients. RESULTS Among those receiving crenezumab, 89% of SC and 86% of IV patients had lower levels of oAβ at week 69 versus baseline. The difference in the proportion of patients with decreasing levels was significant for both treatment arms: p = 0.0035 for SC and p = 0.01 for IV crenezumab versus placebo. The median percentage change was -48% in the SC arm and -43% in the IV arm. No systematic change was observed in the placebo group, with a median change of -13% and equivalent portions with negative and positive change. INTERPRETATION Crenezumab lowered CSF oAβ levels in the large majority of treated patients tested. These results support engagement of the principal pathobiological target in AD and identify CSF oAβ as a novel pharmacodynamic biomarker for use in trials of anti-Aβ agents. ANN NEUROL 2019;86:215-224.
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Affiliation(s)
- Ting Yang
- Ann Romney Center for Neurologic Diseases, Department of NeurologyBrigham and Women's Hospital and Harvard Medical SchoolBostonMA
| | - Yifan Dang
- Ann Romney Center for Neurologic Diseases, Department of NeurologyBrigham and Women's Hospital and Harvard Medical SchoolBostonMA
| | - Beth Ostaszewski
- Ann Romney Center for Neurologic Diseases, Department of NeurologyBrigham and Women's Hospital and Harvard Medical SchoolBostonMA
| | - David Mengel
- Ann Romney Center for Neurologic Diseases, Department of NeurologyBrigham and Women's Hospital and Harvard Medical SchoolBostonMA
| | - Verena Steffen
- Genentech (a member of the Roche Group)South San FranciscoCA
| | - Christina Rabe
- Genentech (a member of the Roche Group)South San FranciscoCA
| | - Tobias Bittner
- Genentech (a member of the Roche Group)South San FranciscoCA
| | - Dominic M. Walsh
- Ann Romney Center for Neurologic Diseases, Department of NeurologyBrigham and Women's Hospital and Harvard Medical SchoolBostonMA
| | - Dennis J. Selkoe
- Ann Romney Center for Neurologic Diseases, Department of NeurologyBrigham and Women's Hospital and Harvard Medical SchoolBostonMA
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Agrawal N, Skelton AA. Structure and Function of Alzheimer’s Amyloid βeta Proteins from Monomer to Fibrils: A Mini Review. Protein J 2019; 38:425-434. [DOI: 10.1007/s10930-019-09854-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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10
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Functional detection of botulinum neurotoxin serotypes A to F by monoclonal neoepitope-specific antibodies and suspension array technology. Sci Rep 2019; 9:5531. [PMID: 30940836 PMCID: PMC6445094 DOI: 10.1038/s41598-019-41722-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/15/2019] [Indexed: 12/26/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are the most potent toxins known and cause the life threatening disease botulism. Sensitive and broad detection is extremely challenging due to the toxins’ high potency and molecular heterogeneity with several serotypes and more than 40 subtypes. The toxicity of BoNT is mediated by enzymatic cleavage of different synaptic proteins involved in neurotransmitter release at serotype-specific cleavage sites. Hence, active BoNTs can be monitored and distinguished in vitro by detecting their substrate cleavage products. In this work, we developed a comprehensive panel of monoclonal neoepitope antibodies (Neo-mAbs) highly specific for the newly generated N- and/or C-termini of the substrate cleavage products of BoNT serotypes A to F. The Neo-mAbs were implemented in a set of three enzymatic assays for the simultaneous detection of two BoNT serotypes each by monitoring substrate cleavage on colour-coded magnetic Luminex-beads. For the first time, all relevant serotypes could be detected in parallel by a routine in vitro activity assay in spiked serum and food samples yielding excellent detection limits in the range of the mouse bioassay or better (0.3–80 pg/mL). Therefore, this work represents a major step towards the replacement of the mouse bioassay for botulism diagnostics.
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Julian MC, Rabia LA, Desai AA, Arsiwala A, Gerson JE, Paulson HL, Kane RS, Tessier PM. Nature-inspired design and evolution of anti-amyloid antibodies. J Biol Chem 2019; 294:8438-8451. [PMID: 30918024 DOI: 10.1074/jbc.ra118.004731] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 03/21/2019] [Indexed: 12/17/2022] Open
Abstract
Antibodies that recognize amyloidogenic aggregates with high conformational and sequence specificity are important for detecting and potentially treating a wide range of neurodegenerative disorders, including Alzheimer's and Parkinson's diseases. However, these types of antibodies are challenging to generate because of the large size, hydrophobicity, and heterogeneity of protein aggregates. To address this challenge, we developed a method for generating antibodies specific for amyloid aggregates. First, we grafted amyloidogenic peptide segments from the target polypeptide [Alzheimer's amyloid-β (Aβ) peptide] into the complementarity-determining regions (CDRs) of a stable antibody scaffold. Next, we diversified the grafted and neighboring CDR sites using focused mutagenesis to sample each WT or grafted residue, as well as one to five of the most commonly occurring amino acids at each site in human antibodies. Finally, we displayed these antibody libraries on the surface of yeast cells and selected antibodies that strongly recognize Aβ-amyloid fibrils and only weakly recognize soluble Aβ. We found that this approach enables the generation of monovalent and bivalent antibodies with nanomolar affinity for Aβ fibrils. These antibodies display high conformational and sequence specificity as well as low levels of nonspecific binding and recognize a conformational epitope at the extreme N terminus of human Aβ. We expect that this systematic approach will be useful for generating antibodies with conformational and sequence specificity against a wide range of peptide and protein aggregates associated with neurodegenerative disorders.
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Affiliation(s)
- Mark C Julian
- Isermann Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Lilia A Rabia
- Isermann Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180; Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, Michigan 48109; Department of Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109; Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109
| | - Alec A Desai
- Department of Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109; Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109
| | - Ammar Arsiwala
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Julia E Gerson
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, Michigan 48109; Department of Protein Folding Disease Initiative, University of Michigan, Ann Arbor, Michigan 48109; Department of Michigan Alzheimer's Disease Center, University of Michigan, Ann Arbor, Michigan 48109
| | - Ravi S Kane
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Peter M Tessier
- Isermann Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180; Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, Michigan 48109; Department of Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109; Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109; Department of Protein Folding Disease Initiative, University of Michigan, Ann Arbor, Michigan 48109; Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109.
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12
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Kozin SA, Barykin EP, Mitkevich VA, Makarov AA. Anti-amyloid Therapy of Alzheimer's Disease: Current State and Prospects. BIOCHEMISTRY (MOSCOW) 2018; 83:1057-1067. [PMID: 30472944 DOI: 10.1134/s0006297918090079] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Drug development for the treatment of Alzheimer's disease (AD) has been for a long time focused on agents that were expected to support endogenous β-amyloid (Aβ) in a monomeric state and destroy soluble Aβ oligomers and insoluble Aβ aggregates. However, this strategy has failed over the last 20 years and was eventually abandoned. In this review, we propose a new approach to the anti-amyloid AD therapy based on the latest achievements in understanding molecular causes of cerebral amyloidosis in AD animal models.
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Affiliation(s)
- S A Kozin
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - E P Barykin
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - V A Mitkevich
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia.
| | - A A Makarov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia.
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13
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Fang XT, Hultqvist G, Meier SR, Antoni G, Sehlin D, Syvänen S. High detection sensitivity with antibody-based PET radioligand for amyloid beta in brain. Neuroimage 2018; 184:881-888. [PMID: 30300753 DOI: 10.1016/j.neuroimage.2018.10.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/04/2018] [Indexed: 11/17/2022] Open
Abstract
PET imaging of amyloid-beta (Aβ) deposits in brain has become an important aid in Alzheimer's disease diagnosis, and an inclusion criterion for patient enrolment into clinical trials of new anti-Aβ treatments. Available PET radioligands visualizing Aβ bind to insoluble fibrils, i.e. Aβ plaques. Levels of prefibrillar Aβ forms, e.g. soluble oligomers and protofibrils, correlate better than plaques with disease severity and these soluble species are the neurotoxic form of Aβ leading to neurodegeneration. The goal was to create an antibody-based radioligand, recognizing not only fibrillary Aβ, but also smaller and still soluble aggregates. We designed and expressed a small recombinant bispecific antibody construct, di-scFv 3D6-8D3, targeting the Aβ N-terminus and the transferrin receptor (TfR). Natively expressed at the blood-brain barrier (BBB), TfR could thus be used as a brain-blood shuttle. Di-scFv 3D6-8D3 bound to Aβ1-40 with high affinity and to TfR with moderate affinity. Di-scFv [124I]3D6-8D3 was injected in two transgenic mouse models overexpressing human Aβ and wild-type control mice and PET scanned at 14, 24 or 72 h after injection. Di-scFv [124I]3D6-8D3 was retained in brain of transgenic animals while it was cleared from wild-type lacking Aβ. This difference was observed from 24 h onwards, and at 72 h, 18 months old transgenic animals, with high load of Aβ pathology, displayed SUVR of 2.2-3.5 in brain while wild-type showed ratios close to unity. A subset of the mice were also scanned with [11C]PIB. Again wt mice displayed ratios of unity while transgenes showed slightly, non-significantly, elevated SUVR of 1.2, indicating improved sensitivity with novel di-scFv [124I]3D6-8D3 compared with [11C]PIB. Brain concentrations of di-scFv [124I]3D6-8D3 correlated with soluble Aβ (p < 0.0001) but not with total Aβ, i.e. plaque load (p = 0.34). We have successfully created a small bispecific antibody-based radioligand capable of crossing the BBB, subsequently binding to and visualizing intrabrain Aβ in vivo. The radioligand displayed better sensitivity compared with [11C]PIB, and brain concentrations correlated with soluble neurotoxic Aβ aggregates.
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Affiliation(s)
- Xiaotian T Fang
- Department of Public Health and Caring Sciences / Geriatrics, Uppsala University, Uppsala, Sweden.
| | - Greta Hultqvist
- Department of Public Health and Caring Sciences / Geriatrics, Uppsala University, Uppsala, Sweden; Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Silvio R Meier
- Department of Public Health and Caring Sciences / Geriatrics, Uppsala University, Uppsala, Sweden
| | - Gunnar Antoni
- Department of Medicinal Chemistry, Preclinical PET Platform, Uppsala University, Uppsala, Sweden; PET Centre, Uppsala University Hospital, Uppsala, Sweden
| | - Dag Sehlin
- Department of Public Health and Caring Sciences / Geriatrics, Uppsala University, Uppsala, Sweden
| | - Stina Syvänen
- Department of Public Health and Caring Sciences / Geriatrics, Uppsala University, Uppsala, Sweden
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14
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Jiang X, Cao Y, Han W. In Silico Study of Recognition between Aβ 40 and Aβ 40 Fibril Surfaces: An N-Terminal Helical Recognition Motif and Its Implications for Inhibitor Design. ACS Chem Neurosci 2018; 9:935-944. [PMID: 29281261 DOI: 10.1021/acschemneuro.7b00359] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The recent finding that the surface of amyloid-β (Aβ) fibril can recruit Aβ peptides and convert them into toxic oligomers has rendered fibril surfaces attractive as inhibition targets. Through extensive simulations with hybrid-resolution and all-atom models, we have investigated how Aβ1-40 recognizes its own fibril surfaces. These calculations give a ∼2.6-5.6 μM half-saturation concentration of Aβ on the surface (cf. experimental value ∼6 μM). Aβ was found to preferentially bind to region 16-24 of Aβ40 fibrils through both electrostatic and van der Waals forces. Both terminal regions of Aβ contribute significantly to binding energetics. A helical binding pose of the N-terminal region of Aβ (Aβ3-14) not seen before is highly preferred on the fibril surface. Aβ3-14 in a helical form can arrange side chains with similar properties on the same sides of the helix and maximize complementary interactions with side chain arrays characteristic of amyloid fibrils. Helix formation on a fibril surface implies a helix-mediated mechanism for Aβ oligomerization catalyzed by fibrils. We propose an Aβ3-14 analogue that can exhibit enhanced helical character and interactions with Aβ fibrils and may thus be used as a template with which to pursue potent inhibitors of Aβ-fibril interactions.
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Affiliation(s)
- Xuehan Jiang
- Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Yang Cao
- Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Wei Han
- Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
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15
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Structural and kinetic basis for the selectivity of aducanumab for aggregated forms of amyloid-β. Sci Rep 2018; 8:6412. [PMID: 29686315 PMCID: PMC5913127 DOI: 10.1038/s41598-018-24501-0] [Citation(s) in RCA: 156] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/05/2018] [Indexed: 12/21/2022] Open
Abstract
Aducanumab, a human-derived antibody targeting amyloid-β (Aβ), is in Phase 3 clinical trials for the treatment of Alzheimer’s disease. Biochemical and structural analyses show that aducanumab binds a linear epitope formed by amino acids 3–7 of the Aβ peptide. Aducanumab discriminates between monomers and oligomeric or fibrillar aggregates based on weak monovalent affinity, fast binding kinetics and strong avidity for epitope-rich aggregates. Direct comparative studies with analogs of gantenerumab, bapineuzumab and solanezumab demonstrate clear differentiation in the binding properties of these antibodies. The crystal structure of the Fab fragment of aducanumab bound to its epitope peptide reveals that aducanumab binds to the N terminus of Aβ in an extended conformation, distinct from those seen in structures with other antibodies that target this immunodominant epitope. Aducanumab recognizes a compact epitope that sits in a shallow pocket on the antibody surface. In silico analyses suggest that aducanumab interacts weakly with the Aβ monomer and may accommodate a variety of peptide conformations, further supporting its selectivity for Aβ aggregates. Our studies provide a structural rationale for the low affinity of aducanumab for non-pathogenic monomers and its greater selectivity for aggregated forms than is seen for other Aβ-targeting antibodies.
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16
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Sumner IL, Edwards RA, Asuni AA, Teeling JL. Antibody Engineering for Optimized Immunotherapy in Alzheimer's Disease. Front Neurosci 2018; 12:254. [PMID: 29740272 PMCID: PMC5924811 DOI: 10.3389/fnins.2018.00254] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/03/2018] [Indexed: 12/17/2022] Open
Abstract
There are nearly 50 million people with Alzheimer's disease (AD) worldwide and currently no disease modifying treatment is available. AD is characterized by deposits of Amyloid-β (Aβ), neurofibrillary tangles, and neuroinflammation, and several drug discovery programmes studies have focussed on Aβ as therapeutic target. Active immunization and passive immunization against Aβ leads to the clearance of deposits in humans and transgenic mice expressing human Aβ but have failed to improve memory loss. This review will discuss the possible explanations for the lack of efficacy of Aβ immunotherapy, including the role of a pro-inflammatory response and subsequent vascular side effects, the binding site of therapeutic antibodies and the timing of the treatment. We further discuss how antibodies can be engineered for improved efficacy.
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Affiliation(s)
- Isabelle L Sumner
- Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Ross A Edwards
- Biological Sciences, University of Southampton, Southampton, United Kingdom
| | | | - Jessica L Teeling
- Biological Sciences, University of Southampton, Southampton, United Kingdom
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17
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18
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Rajasekhar K, Govindaraju T. Current progress, challenges and future prospects of diagnostic and therapeutic interventions in Alzheimer's disease. RSC Adv 2018; 8:23780-23804. [PMID: 35540246 PMCID: PMC9081849 DOI: 10.1039/c8ra03620a] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/04/2018] [Indexed: 01/04/2023] Open
Abstract
The diverse pathological mechanisms and their implications for the development of effective diagnostic and therapeutic interventions in Alzheimer's disease are presented with current progress, challenges and future prospects.
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Affiliation(s)
- K. Rajasekhar
- Bioorganic Chemistry Laboratory
- New Chemistry Unit
- Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR)
- Bengaluru 560064
- India
| | - Thimmaiah Govindaraju
- Bioorganic Chemistry Laboratory
- New Chemistry Unit
- Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR)
- Bengaluru 560064
- India
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19
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Zhao J, Nussinov R, Ma B. Mechanisms of recognition of amyloid-β (Aβ) monomer, oligomer, and fibril by homologous antibodies. J Biol Chem 2017; 292:18325-18343. [PMID: 28924036 DOI: 10.1074/jbc.m117.801514] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/26/2017] [Indexed: 12/31/2022] Open
Abstract
Alzheimer's disease is one of the most devastating neurodegenerative diseases without effective therapies. Immunotherapy is a promising approach, but amyloid antibody structural information is limited. Here we simulate the recognition of monomeric, oligomeric, and fibril amyloid-β (Aβ) by three homologous antibodies (solanezumab, crenezumab, and their chimera, CreneFab). Solanezumab only binds the monomer, whereas crenezumab and CreneFab can recognize different oligomerization states; however, the structural basis for this observation is not understood. We successfully identified stable complexes of crenezumab with Aβ pentamer (oligomer model) and 16-mer (fibril model). It is noteworthy that solanezumab targets Aβ residues 16-26 preferentially in the monomeric state; conversely, crenezumab consistently targets residues 13-16 in different oligomeric states. Unlike the buried monomeric peptide in solanezumab's complementarity-determining region, crenezumab binds the oligomer's lateral and edge residues. Surprisingly, crenezumab's complementarity-determining region loops can effectively bind the Aβ fibril lateral surface around the same 13-16 region. The constant domain influences antigen recognition through entropy redistribution. Different constant domain residues in solanezumab/crenezumab/chimera influence the binding of Aβ aggregates. Collectively, we provide molecular insight into the recognition mechanisms facilitating antibody design.
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Affiliation(s)
- Jun Zhao
- From the Cancer and Inflammation Program, NCI-Frederick, Frederick, Maryland 21702
| | - Ruth Nussinov
- the Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, NCI-Frederick, Frederick, Maryland 21702, and.,the Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Buyong Ma
- the Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, NCI-Frederick, Frederick, Maryland 21702, and
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20
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Teplyakov A, Obmolova G, Gilliland GL. A coiled conformation of amyloid-β recognized by antibody C706. ALZHEIMERS RESEARCH & THERAPY 2017; 9:66. [PMID: 28830506 PMCID: PMC5568176 DOI: 10.1186/s13195-017-0296-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 08/03/2017] [Indexed: 01/23/2023]
Abstract
Background β-Amyloid (Aβ) peptide is believed to play a pivotal role in the development of Alzheimer’s disease. Passive immunization with anti-Aβ monoclonal antibodies may facilitate the clearance of Aβ in the brain and may thus prevent the downstream pathology. Antibodies targeting the immunodominant N-terminal epitope of Aβ and capable of binding both the plaques and soluble species have been most efficacious in animal models. Structural studies of such antibodies with bound Aβ peptides provided the basis for understanding the mechanisms of action and the differences in potency. To gain further insight into the structural determinants of antigen recognition and the preferential Aβ conformations, we determined the crystal structure of murine antibody C706 in complex with the N-terminal Aβ 1–16 peptide sequence. Methods The antigen-binding fragment of C706 was expressed in HEK293 cells and was crystallized in complex with the Aβ peptide. The X-ray structure was determined at 1.9-Å resolution. Results The binding epitope of C706 is centered on residues Arg5 and His6, which provide the majority of interactions. Unlike most antibodies, C706 recognizes a coiled rather than extended conformation of Aβ. Conclusions Comparison with other antibodies targeting the N-terminal section of Aβ suggests that the conformation of the bound peptide may be linked to the immunization protocol and may reflect the preference for the extended conformation in the context of a longer Aβ peptide as opposed to the coiled conformation in the isolated short peptide.
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Affiliation(s)
- Alexey Teplyakov
- Janssen Research and Development, LLC, 1400 McKean Road, Spring House, PA, 19477, USA.
| | - Galina Obmolova
- Janssen Research and Development, LLC, 1400 McKean Road, Spring House, PA, 19477, USA
| | - Gary L Gilliland
- Janssen Research and Development, LLC, 1400 McKean Road, Spring House, PA, 19477, USA
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21
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Piechotta A, Parthier C, Kleinschmidt M, Gnoth K, Pillot T, Lues I, Demuth HU, Schilling S, Rahfeld JU, Stubbs MT. Structural and functional analyses of pyroglutamate-amyloid-β-specific antibodies as a basis for Alzheimer immunotherapy. J Biol Chem 2017. [PMID: 28623233 DOI: 10.1074/jbc.m117.777839] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Alzheimer disease is associated with deposition of the amyloidogenic peptide Aβ in the brain. Passive immunization using Aβ-specific antibodies has been demonstrated to reduce amyloid deposition both in vitro and in vivo Because N-terminally truncated pyroglutamate (pE)-modified Aβ species (AβpE3) exhibit enhanced aggregation potential and propensity to form toxic oligomers, they represent particularly attractive targets for antibody therapy. Here we present three separate monoclonal antibodies that specifically recognize AβpE3 with affinities of 1-10 nm and inhibit AβpE3 fibril formation in vitro. In vivo application of one of these resulted in improved memory in AβpE3 oligomer-treated mice. Crystal structures of Fab-AβpE3 complexes revealed two distinct binding modes for the peptide. Juxtaposition of pyroglutamate pE3 and the F4 side chain (the "pEF head") confers a pronounced bulky hydrophobic nature to the AβpE3 N terminus that might explain the enhanced aggregation properties of the modified peptide. The deep burial of the pEF head by two of the antibodies explains their high target specificity and low cross-reactivity, making them promising candidates for the development of clinical antibodies.
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Affiliation(s)
- Anke Piechotta
- Probiodrug AG, Weinbergweg 22, 06120 Halle (Saale), Germany; Institute of Biotechnology, Martin Luther University, 06108 Halle-Wittenberg, Germany; Department of Molecular Drug Biochemistry and Therapy, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | - Christoph Parthier
- Institute of Biotechnology, Martin Luther University, 06108 Halle-Wittenberg, Germany
| | - Martin Kleinschmidt
- Probiodrug AG, Weinbergweg 22, 06120 Halle (Saale), Germany; Department of Molecular Drug Biochemistry and Therapy, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | - Kathrin Gnoth
- Probiodrug AG, Weinbergweg 22, 06120 Halle (Saale), Germany; Department of Molecular Drug Biochemistry and Therapy, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | | | - Inge Lues
- Probiodrug AG, Weinbergweg 22, 06120 Halle (Saale), Germany
| | - Hans-Ulrich Demuth
- Probiodrug AG, Weinbergweg 22, 06120 Halle (Saale), Germany; Department of Molecular Drug Biochemistry and Therapy, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | - Stephan Schilling
- Probiodrug AG, Weinbergweg 22, 06120 Halle (Saale), Germany; Department of Molecular Drug Biochemistry and Therapy, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | - Jens-Ulrich Rahfeld
- Probiodrug AG, Weinbergweg 22, 06120 Halle (Saale), Germany; Department of Molecular Drug Biochemistry and Therapy, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany.
| | - Milton T Stubbs
- Institute of Biotechnology, Martin Luther University, 06108 Halle-Wittenberg, Germany.
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22
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Potocnakova L, Bhide M, Pulzova LB. An Introduction to B-Cell Epitope Mapping and In Silico Epitope Prediction. J Immunol Res 2016; 2016:6760830. [PMID: 28127568 PMCID: PMC5227168 DOI: 10.1155/2016/6760830] [Citation(s) in RCA: 192] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/21/2016] [Accepted: 12/13/2016] [Indexed: 01/09/2023] Open
Abstract
Identification of B-cell epitopes is a fundamental step for development of epitope-based vaccines, therapeutic antibodies, and diagnostic tools. Epitope-based antibodies are currently the most promising class of biopharmaceuticals. In the last decade, in-depth in silico analysis and categorization of the experimentally identified epitopes stimulated development of algorithms for epitope prediction. Recently, various in silico tools are employed in attempts to predict B-cell epitopes based on sequence and/or structural data. The main objective of epitope identification is to replace an antigen in the immunization, antibody production, and serodiagnosis. The accurate identification of B-cell epitopes still presents major challenges for immunologists. Advances in B-cell epitope mapping and computational prediction have yielded molecular insights into the process of biorecognition and formation of antigen-antibody complex, which may help to localize B-cell epitopes more precisely. In this paper, we have comprehensively reviewed state-of-the-art experimental methods for B-cell epitope identification, existing databases for epitopes, and novel in silico resources and prediction tools available online. We have also elaborated new trends in the antibody-based epitope prediction. The aim of this review is to assist researchers in identification of B-cell epitopes.
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Affiliation(s)
- Lenka Potocnakova
- Laboratory of Biomedical Microbiology and Immunology, Department of Microbiology and Immunology, The University of Veterinary Medicine and Pharmacy in Kosice, 041 81 Kosice, Slovakia
| | - Mangesh Bhide
- Laboratory of Biomedical Microbiology and Immunology, Department of Microbiology and Immunology, The University of Veterinary Medicine and Pharmacy in Kosice, 041 81 Kosice, Slovakia
- Institute of Neuroimmunology of Slovak Academy of Sciences, 845 10 Bratislava, Slovakia
| | - Lucia Borszekova Pulzova
- Laboratory of Biomedical Microbiology and Immunology, Department of Microbiology and Immunology, The University of Veterinary Medicine and Pharmacy in Kosice, 041 81 Kosice, Slovakia
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23
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Ma B, Zhao J, Nussinov R. Conformational selection in amyloid-based immunotherapy: Survey of crystal structures of antibody-amyloid complexes. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1860:2672-81. [PMID: 27266343 PMCID: PMC5610039 DOI: 10.1016/j.bbagen.2016.05.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/05/2016] [Accepted: 05/31/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND The dominant feature in neurodegenerative diseases is protein aggregations that lead to neuronal loss. Immunotherapies using antibodies or antibody fragments to target the aggregations are a highly perused approach. The molecular mechanisms underlying the amyloid-based immunotherapy are complex. Deciphering the properties of amyloidogenic proteins responsible for these diseases is essential to obtain insights into antibody recognition of the amyloid antigens. SCOPE OF REVIEW We systematically explore all available crystal structures of antibody-amyloid complexes related to neurodegenerative diseases, including antibodies that recognize the Aβ peptide, tau protein, prion protein, alpha-synuclein, huntingtin protein (mHTT), and polyglutamine. MAJOR CONCLUSIONS We found that antibodies mostly use the conformational selection mechanism to recognize the highly flexible amyloid antigens. In particular, solanezumab bound to Aβ12-28 tripeptide motif conformation (F19F20A21), which is shared with the Aβ42 fibril. This motif, which is trapped by the antibody, may provide the missing link in amyloid formation. Water molecules often bridge between the antibody and amyloid, contributing to the recognition. GENERAL SIGNIFICANCE This paper provides the structural basis for antibody recognition of amyloidogenic proteins. The analysis and discussion of known structures are expected to help in the design and optimization of antibodies in neurodegenerative diseases. This article is part of a Special Issue entitled "System Genetics" Guest Editor: Dr. Yudong Cai and Dr. Tao Huang.
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Affiliation(s)
- Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, United States.
| | - Jun Zhao
- Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, United States
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, United States; Sackler Inst. of Molecular Medicine, Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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24
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Zhao J, Ma B, Nussinov R. Compilation and Analysis of Enzymes, Engineered Antibodies, and Nanoparticles Designed to Interfere with Amyloid-β Aggregation. Isr J Chem 2016. [DOI: 10.1002/ijch.201600093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jun Zhao
- Cancer and Inflammation Program; National Cancer Institute; Frederick Maryland 21702 USA
| | - Buyong Ma
- Basic Science Program; Leidos Biomedical Research, Inc.; Cancer and Inflammation Program; National Cancer Institute; Frederick Maryland 21702 USA
| | - Ruth Nussinov
- Basic Science Program; Leidos Biomedical Research, Inc.; Cancer and Inflammation Program; National Cancer Institute; Frederick Maryland 21702 USA
- Sackler Institute of Molecular Medicine; Department of Human Genetics and Molecular Medicine; Sackler School of Medicine; Tel Aviv University; Tel Aviv 69978 Israel
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25
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Szczepankiewicz O, Linse B, Meisl G, Thulin E, Frohm B, Frigerio CS, Colvin MT, Jacavone AC, Griffin RG, Knowles T, Walsh DM, Linse S. N-Terminal Extensions Retard Aβ42 Fibril Formation but Allow Cross-Seeding and Coaggregation with Aβ42. J Am Chem Soc 2015; 137:14673-85. [PMID: 26535489 PMCID: PMC5412961 DOI: 10.1021/jacs.5b07849] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyloid β-protein (Aβ) sequence length variants with varying aggregation propensity coexist in vivo, where coaggregation and cross-catalysis phenomena may affect the aggregation process. Until recently, naturally occurring amyloid β-protein (Aβ) variants were believed to begin at or after the canonical β-secretase cleavage site within the amyloid β-protein precursor. However, N-terminally extended forms of Aβ (NTE-Aβ) were recently discovered and may contribute to Alzheimer's disease. Here, we have used thioflavin T fluorescence to study the aggregation kinetics of Aβ42 variants with N-terminal extensions of 5-40 residues, and transmission electron microscopy to analyze the end states. We find that all variants form amyloid fibrils of similar morphology as Aβ42, but the half-time of aggregation (t1/2) increases exponentially with extension length. Monte Carlo simulations of model peptides suggest that the retardation is due to an underlying general physicochemical effect involving reduced frequency of productive molecular encounters. Indeed, global kinetic analyses reveal that NTE-Aβ42s form fibrils via the same mechanism as Aβ42, but all microscopic rate constants (primary and secondary nucleation, elongation) are reduced for the N-terminally extended variants. Still, Aβ42 and NTE-Aβ42 coaggregate to form mixed fibrils and fibrils of either Aβ42 or NTE-Aβ42 catalyze aggregation of all monomers. NTE-Aβ42 monomers display reduced aggregation rate with all kinds of seeds implying that extended termini interfere with the ability of monomers to nucleate or elongate. Cross-seeding or coaggregation may therefore represent an important contribution in the in vivo formation of assemblies believed to be important in disease.
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Affiliation(s)
- Olga Szczepankiewicz
- Department of Biochemistry and Structural Biology, Lund University, P O Box 124, 221 00 Lund, Sweden
| | - Björn Linse
- Department of Biochemistry and Structural Biology, Lund University, P O Box 124, 221 00 Lund, Sweden
| | - Georg Meisl
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Eva Thulin
- Department of Biochemistry and Structural Biology, Lund University, P O Box 124, 221 00 Lund, Sweden
| | - Birgitta Frohm
- Department of Biochemistry and Structural Biology, Lund University, P O Box 124, 221 00 Lund, Sweden
| | - Carlo Sala Frigerio
- Laboratory for Neurodegenerative Research, Conway Institute of Biomedical and Biomolecular Research, University College Dublin, Belfield, Dublin 4, Republic of Ireland
| | - Michael T. Colvin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Angela C. Jacavone
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Robert G. Griffin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Tuomas Knowles
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Dominic M. Walsh
- Laboratory for Neurodegenerative Research, Conway Institute of Biomedical and Biomolecular Research, University College Dublin, Belfield, Dublin 4, Republic of Ireland
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Sara Linse
- Department of Biochemistry and Structural Biology, Lund University, P O Box 124, 221 00 Lund, Sweden
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Bouter Y, Lopez Noguerola JS, Tucholla P, Crespi GAN, Parker MW, Wiltfang J, Miles LA, Bayer TA. Abeta targets of the biosimilar antibodies of Bapineuzumab, Crenezumab, Solanezumab in comparison to an antibody against N‑truncated Abeta in sporadic Alzheimer disease cases and mouse models. Acta Neuropathol 2015; 130:713-29. [PMID: 26467270 DOI: 10.1007/s00401-015-1489-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/05/2015] [Accepted: 10/05/2015] [Indexed: 01/01/2023]
Abstract
Solanezumab and Crenezumab are two humanized antibodies targeting Amyloid-β (Aβ) which are currently tested in multiple clinical trials for the prevention of Alzheimer's disease. However, there is a scientific discussion ongoing about the target engagement of these antibodies. Here, we report the immunohistochemical staining profiles of biosimilar antibodies of Solanezumab, Crenezumab and Bapineuzumab in human formalin-fixed, paraffin-embedded tissue and human fresh frozen tissue. Furthermore, we performed a direct comparative immunohistochemistry analysis of the biosimilar versions of the humanized antibodies in different mouse models including 5XFAD, Tg4-42, TBA42, APP/PS1KI, 3xTg. The staining pattern with these humanized antibodies revealed a surprisingly similar profile. All three antibodies detected plaques, cerebral amyloid angiopathy and intraneuronal Aβ in a similar fashion. Remarkably, Solanezumab showed a strong binding affinity to plaques. We also reaffirmed that Bapineuzumab does not recognize N-truncated or modified Aβ, while Solanezumab and Crenezumab do detect N-terminally modified Aβ peptides Aβ4-42 and pyroglutamate Aβ3-42. In addition, we compared the results with the staining pattern of the mouse NT4X antibody that recognizes specifically Aβ4-42 and pyroglutamate Aβ3-42, but not full-length Aβ1-42. In contrast to the biosimilar antibodies of Solanezumab, Crenezumab and Bapineuzumab, the murine NT4X antibody shows a unique target engagement. NT4X does barely cross-react with amyloid plaques in human tissue. It does, however, detect cerebral amyloid angiopathy in human tissue. In Alzheimer mouse models, NT4X detects intraneuronal Aβ and plaques comparable to the humanized antibodies. In conclusion, the biosimilar antibodies Solanezumab, Crenezumab and Bapineuzumab strongly react with amyloid plaques, which are in contrast to the NT4X antibody that hardly recognizes plaques in human tissue. Therefore, NT4X is the first of a new class of therapeutic antibodies.
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Crespi GAN, Hermans SJ, Parker MW, Miles LA. Molecular basis for mid-region amyloid-β capture by leading Alzheimer's disease immunotherapies. Sci Rep 2015; 5:9649. [PMID: 25880481 PMCID: PMC4549621 DOI: 10.1038/srep09649] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 03/12/2015] [Indexed: 12/24/2022] Open
Abstract
Solanezumab (Eli Lilly) and crenezumab (Genentech) are the leading clinical antibodies targeting Amyloid-β (Aβ) to be tested in multiple Phase III clinical trials for the prevention of Alzheimer's disease in at-risk individuals. Aβ capture by these clinical antibodies is explained here with the first reported mid-region Aβ-anti-Aβ complex crystal structure. Solanezumab accommodates a large Aβ epitope (960 Å(2) buried interface over residues 16 to 26) that forms extensive contacts and hydrogen bonds to the antibody, largely via main-chain Aβ atoms and a deeply buried Phe19-Phe20 dipeptide core. The conformation of Aβ captured is an intermediate between observed sheet and helical forms with intramolecular hydrogen bonds stabilising residues 20-26 in a helical conformation. Remarkably, Aβ-binding residues are almost perfectly conserved in crenezumab. The structure explains the observed shared cross reactivity of solanezumab and crenezumab with proteins abundant in plasma that exhibit this Phe-Phe dipeptide.
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MESH Headings
- Alzheimer Disease/therapy
- Amyloid beta-Peptides/chemistry
- Amyloid beta-Peptides/immunology
- Amyloid beta-Peptides/metabolism
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Monoclonal, Humanized/chemistry
- Antibodies, Monoclonal, Humanized/immunology
- Antibodies, Monoclonal, Humanized/therapeutic use
- Binding Sites
- Crystallography, X-Ray
- Dipeptides/blood
- Dipeptides/immunology
- Humans
- Hydrogen Bonding
- Immunotherapy
- Molecular Dynamics Simulation
- Protein Structure, Tertiary
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Affiliation(s)
- Gabriela A. N. Crespi
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, Victoria 3065, Australia
| | - Stefan J. Hermans
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, Victoria 3065, Australia
| | - Michael W. Parker
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, Victoria 3065, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Luke A. Miles
- ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, Victoria 3065, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
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Yang T, O'Malley TT, Kanmert D, Jerecic J, Zieske LR, Zetterberg H, Hyman BT, Walsh DM, Selkoe DJ. A highly sensitive novel immunoassay specifically detects low levels of soluble Aβ oligomers in human cerebrospinal fluid. ALZHEIMERS RESEARCH & THERAPY 2015; 7:14. [PMID: 25802556 PMCID: PMC4369838 DOI: 10.1186/s13195-015-0100-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 01/22/2015] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Amyloid β-protein oligomers play a key role in Alzheimer's disease (AD), but well-validated assays that routinely detect them in cerebrospinal fluid (CSF) are just emerging. We sought to confirm and extend a recent study using the Singulex Erenna platform that reported increased mean CSF oligomer levels in AD. METHODS We tested four antibody pairs and chose one pair that was particularly sensitive, using 1C22, our new oligomer-selective monoclonal antibody, for capture. We applied this new assay to extracts of human brain and CSF. RESULTS A combination of 1C22 for capture and 3D6 for detection yielded an Erenna immunoassay with a lower limit of quantification of approximately 0.15 pg/ml that was highly selective for oligomers over monomers and detected a wide size-range of oligomers. Most CSFs we tested had detectable oligomer levels but with a large overlap between AD and controls and a trend for higher mean levels in mild cognitive impairment (MCI) than controls. CONCLUSION Aβ oligomers are detectable in most human CSFs, but AD and controls overlap. MCI CSFs may have a modest elevation in mean value by this assay.
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Affiliation(s)
- Ting Yang
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School Boston, 77 Avenue Louis Pasteur, Harvard Institute Medical, Room 730, Boston, MA 02115 USA
| | - Tiernan T O'Malley
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School Boston, 77 Avenue Louis Pasteur, Harvard Institute Medical, Room 730, Boston, MA 02115 USA
| | - Daniel Kanmert
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School Boston, 77 Avenue Louis Pasteur, Harvard Institute Medical, Room 730, Boston, MA 02115 USA
| | - Jasna Jerecic
- Acumen Pharmaceuticals, Inc., 9816 Easton Drive, Beverly Hills, CA 90210 USA
| | - Lynn R Zieske
- Singulex, Inc., 1701 Harbor Bay Parkway, Suite 200, Alameda, CA USA
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, S-431 80 Mölndal, Sweden ; UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | | | - Dominic M Walsh
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School Boston, 77 Avenue Louis Pasteur, Harvard Institute Medical, Room 730, Boston, MA 02115 USA
| | - Dennis J Selkoe
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School Boston, 77 Avenue Louis Pasteur, Harvard Institute Medical, Room 730, Boston, MA 02115 USA
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Watt AD, Crespi GAN, Down RA, Ascher DB, Gunn A, Perez KA, McLean CA, Villemagne VL, Parker MW, Barnham KJ, Miles LA. Anti-Aβ antibody target engagement: a response to Siemers et al. Acta Neuropathol 2014; 128:611-4. [PMID: 25120193 DOI: 10.1007/s00401-014-1333-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 08/07/2014] [Indexed: 10/24/2022]
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Welzel AT, Maggio JE, Shankar GM, Walker DE, Ostaszewski BL, Li S, Klyubin I, Rowan MJ, Seubert P, Walsh DM, Selkoe DJ. Secreted amyloid β-proteins in a cell culture model include N-terminally extended peptides that impair synaptic plasticity. Biochemistry 2014; 53:3908-21. [PMID: 24840308 PMCID: PMC4070750 DOI: 10.1021/bi5003053] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
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Evidence
for a central role of amyloid β-protein (Aβ) in the genesis
of Alzheimer’s disease (AD) has led to
advanced human trials of Aβ-lowering agents. The “amyloid
hypothesis” of AD postulates deleterious effects of small,
soluble forms of Aβ on synaptic form and function. Because selectively
targeting synaptotoxic forms of soluble Aβ could be therapeutically
advantageous, it is important to understand the full range of soluble
Aβ derivatives. We previously described a Chinese hamster ovary (CHO) cell line (7PA2 cells) that stably expresses mutant human amyloid precursor protein (APP). Here, we extend this work by purifying an sodium dodecyl sulfate
(SDS)-stable, ∼8 kDa Aβ species
from the 7PA2 medium. Mass spectrometry confirmed its identity as
a noncovalently bonded Aβ40 homodimer that impaired hippocampal
long-term potentiation (LTP) in vivo. We further report the detection
of Aβ-containing fragments of APP in the 7PA2 medium that extend
N-terminal from Asp1 of Aβ. These N-terminally extended Aβ-containing
monomeric fragments are distinct from soluble Aβ oligomers formed
from Aβ1-40/42 monomers and are bioactive synaptotoxins secreted
by 7PA2 cells. Importantly, decreasing β-secretase processing
of APP elevated these alternative synaptotoxic APP fragments. We conclude
that certain synaptotoxic Aβ-containing species can arise from
APP processing events N-terminal to the classical β-secretase
cleavage site.
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