251
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Englund H, Sehlin D, Johansson AS, Nilsson LNG, Gellerfors P, Paulie S, Lannfelt L, Pettersson FE. Sensitive ELISA detection of amyloid-beta protofibrils in biological samples. J Neurochem 2007; 103:334-45. [PMID: 17623042 DOI: 10.1111/j.1471-4159.2007.04759.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Amyloid-beta (Abeta) protofibrils are known intermediates of the in vitro Abeta aggregation process and the protofibrillogenic Arctic mutation (APPE693G) provides clinical support for a pathogenic role of Abeta protofibrils in Alzheimer's disease (AD). To verify their in vivo relevance and to establish a quantitative Abeta protofibril immunoassay, Abeta conformation dependent monoclonal antibodies were generated. One of these antibodies, mAb158 (IgG2a), was used in a sandwich ELISA to specifically detect picomolar concentrations of Abeta protofibrils without interference from Abeta monomers or the amyloid precursor protein (APP). The specificity and biological significance of this ELISA was demonstrated using cell cultures and transgenic mouse models expressing human APP containing the Swedish mutation (APPKN670/671ML), or the Swedish and Arctic mutation in combination. The mAb158 sandwich ELISA analysis revealed presence of Abeta protofibrils in both cell and animal models, proving that Abeta protofibrils are formed not only in vitro, but also in vivo. Furthermore, elevated Abeta protofibril levels in the Arctic-Swedish samples emphasize the usefulness of the Arctic mutation as a model of enhanced protofibril formation. This assay provides a novel tool for investigating the role of Abeta protofibrils in AD and has the potential of becoming an important diagnostic assay.
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Affiliation(s)
- Hillevi Englund
- Department of Public Health/Molecular Geriatrics, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
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252
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De Felice FG, Wu D, Lambert MP, Fernandez SJ, Velasco PT, Lacor PN, Bigio EH, Jerecic J, Acton PJ, Shughrue PJ, Chen-Dodson E, Kinney GG, Klein WL. Alzheimer's disease-type neuronal tau hyperphosphorylation induced by A beta oligomers. Neurobiol Aging 2007; 29:1334-47. [PMID: 17403556 PMCID: PMC3142933 DOI: 10.1016/j.neurobiolaging.2007.02.029] [Citation(s) in RCA: 310] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2006] [Revised: 02/26/2007] [Accepted: 02/27/2007] [Indexed: 01/03/2023]
Abstract
Alzheimer's disease (AD) is characterized by presence of extracellular fibrillar A beta in amyloid plaques, intraneuronal neurofibrillary tangles consisting of aggregated hyperphosphorylated tau and elevated brain levels of soluble A beta oligomers (ADDLs). A major question is how these disparate facets of AD pathology are mechanistically related. Here we show that, independent of the presence of fibrils, ADDLs stimulate tau phosphorylation in mature cultures of hippocampal neurons and in neuroblastoma cells at epitopes characteristically hyperphosphorylated in AD. A monoclonal antibody that targets ADDLs blocked their attachment to synaptic binding sites and prevented tau hyperphosphorylation. Tau phosphorylation was blocked by the Src family tyrosine kinase inhibitor, 4-amino-5-(4-chlorophenyl)-7(t-butyl)pyrazol(3,4-D)pyramide (PP1), and by the phosphatidylinositol-3-kinase inhibitor LY294002. Significantly, tau hyperphosphorylation was also induced by a soluble aqueous extract containing A beta oligomers from AD brains, but not by an extract from non-AD brains. A beta oligomers have been increasingly implicated as the main neurotoxins in AD, and the current results provide a unifying mechanism in which oligomer activity is directly linked to tau hyperphosphorylation in AD pathology.
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Affiliation(s)
- Fernanda G. De Felice
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois, 60208 USA
- Instituto de Bioquíica Médica, Programa de Bioquímica e Biofísica Celular, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21944-590, Brazil
| | - Diana Wu
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois, 60208 USA
| | - Mary P. Lambert
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois, 60208 USA
| | - Sara J. Fernandez
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois, 60208 USA
| | - Pauline T. Velasco
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois, 60208 USA
| | - Pascale N. Lacor
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois, 60208 USA
| | - Eileen H. Bigio
- Neuropathology Core, Cognitive Neurology and Alzheimer’s Disease Center, Northwestern Feinberg School of Medicine, Chicago, IL 60611 USA
| | - Jasna Jerecic
- Acumen Pharmaceuticals, Inc., South San Francisco, CA 94080 USA
| | - Paul J. Acton
- Merck Research Laboratories, Department of Alzheimer’s Research, West Point, PA 19486 USA
| | - Paul J. Shughrue
- Merck Research Laboratories, Department of Alzheimer’s Research, West Point, PA 19486 USA
| | - Elizabeth Chen-Dodson
- Merck Research Laboratories, Department of Alzheimer’s Research, West Point, PA 19486 USA
| | - Gene G. Kinney
- Merck Research Laboratories, Department of Alzheimer’s Research, West Point, PA 19486 USA
| | - William L. Klein
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois, 60208 USA
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253
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Emadi S, Barkhordarian H, Wang MS, Schulz P, Sierks MR. Isolation of a human single chain antibody fragment against oligomeric alpha-synuclein that inhibits aggregation and prevents alpha-synuclein-induced toxicity. J Mol Biol 2007; 368:1132-44. [PMID: 17391701 PMCID: PMC2235820 DOI: 10.1016/j.jmb.2007.02.089] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Revised: 02/19/2007] [Accepted: 02/26/2007] [Indexed: 12/25/2022]
Abstract
Protein misfolding and aggregation are pathological aspects of numerous neurodegenerative diseases. Aggregates of alpha-synuclein are major components of the Lewy bodies and Lewy neurites associated with Parkinson's Disease (PD). A natively unfolded protein, alpha-synuclein can adopt different aggregated morphologies, including oligomers, protofibrils and fibrils. The small oligomeric aggregates have been shown to be particularly toxic. Antibodies that neutralize the neurotoxic aggregates without interfering with beneficial functions of monomeric alpha-synuclein can be useful therapeutics. We were able to isolate single chain antibody fragments (scFvs) from a phage displayed antibody library against the target antigen morphology using a novel biopanning technique that utilizes atomic force microscopy (AFM) to image and immobilize specific morphologies of alpha-synuclein. The scFv described here binds only to an oligomeric form of alpha-synuclein and inhibits both aggregation and toxicity of alpha-synuclein in vitro. This scFv can have potential therapeutic value in controlling misfolding and aggregation of alpha-synuclein in vivo when expressed intracellularly in dopaminergic neurons as an intrabody.
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Affiliation(s)
- Sharareh Emadi
- Department of Chemical and Materials Engineering, Arizona State University, Tempe, AZ 85287-6006, USA
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254
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Lacor PN, Buniel MC, Furlow PW, Sanz Clemente A, Velasco PT, Wood M, Viola KL, Klein WL. Abeta oligomer-induced aberrations in synapse composition, shape, and density provide a molecular basis for loss of connectivity in Alzheimer's disease. J Neurosci 2007; 27:796-807. [PMID: 17251419 PMCID: PMC6672917 DOI: 10.1523/jneurosci.3501-06.2007] [Citation(s) in RCA: 924] [Impact Index Per Article: 54.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The basis for memory loss in early Alzheimer's disease (AD) seems likely to involve synaptic damage caused by soluble Abeta-derived oligomers (ADDLs). ADDLs have been shown to build up in the brain and CSF of AD patients and are known to interfere with mechanisms of synaptic plasticity, acting as gain-of-function ligands that attach to synapses. Because of the correlation between AD dementia and synaptic degeneration, we investigated here the ability of ADDLs to affect synapse composition, structure, and abundance. Using highly differentiated cultures of hippocampal neurons, a preferred model for studies of synapse cell biology, we found that ADDLs bound to neurons with specificity, attaching to presumed excitatory pyramidal neurons but not GABAergic neurons. Fractionation of ADDLs bound to forebrain synaptosomes showed association with postsynaptic density complexes containing NMDA receptors, consistent with observed attachment of ADDLs to dendritic spines. During binding to hippocampal neurons, ADDLs promoted a rapid decrease in membrane expression of memory-related receptors (NMDA and EphB2). Continued exposure resulted in abnormal spine morphology, with induction of long thin spines reminiscent of the morphology found in mental retardation, deafferentation, and prionoses. Ultimately, ADDLs caused a significant decrease in spine density. Synaptic deterioration, which was accompanied by decreased levels of the spine cytoskeletal protein drebrin, was blocked by the Alzheimer's therapeutic drug Namenda. The observed disruption of dendritic spines links ADDLs to a major facet of AD pathology, providing strong evidence that ADDLs in AD brain cause neuropil damage believed to underlie dementia.
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Affiliation(s)
- Pascale N. Lacor
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208
| | - Maria C. Buniel
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208
| | - Paul W. Furlow
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208
| | - Antonio Sanz Clemente
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208
| | - Pauline T. Velasco
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208
| | - Margaret Wood
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208
| | - Kirsten L. Viola
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208
| | - William L. Klein
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208
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255
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De Felice FG, Velasco PT, Lambert MP, Viola K, Fernandez SJ, Ferreira ST, Klein WL. Abeta oligomers induce neuronal oxidative stress through an N-methyl-D-aspartate receptor-dependent mechanism that is blocked by the Alzheimer drug memantine. J Biol Chem 2007; 282:11590-601. [PMID: 17308309 DOI: 10.1074/jbc.m607483200] [Citation(s) in RCA: 663] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Oxidative stress is a major aspect of Alzheimer disease (AD) pathology. We have investigated the relationship between oxidative stress and neuronal binding of Abeta oligomers (also known as ADDLs). ADDLs are known to accumulate in brain tissue of AD patients and are considered centrally related to pathogenesis. Using hippocampal neuronal cultures, we found that ADDLs stimulated excessive formation of reactive oxygen species (ROS) through a mechanism requiring N-methyl-d-aspartate receptor (NMDA-R) activation. ADDL binding to neurons was reduced and ROS formation was completely blocked by an antibody to the extracellular domain of the NR1 subunit of NMDA-Rs. In harmony with a steric inhibition of ADDL binding by NR1 antibodies, ADDLs that were bound to detergent-extracted synaptosomal membranes co-immunoprecipitated with NMDA-R subunits. The NR1 antibody did not affect ROS formation induced by NMDA, showing that NMDA-Rs themselves remained functional. Memantine, an open channel NMDA-R antagonist prescribed as a memory-preserving drug for AD patients, completely protected against ADDL-induced ROS formation, as did other NMDA-R antagonists. Memantine and the anti-NR1 antibody also attenuated a rapid ADDL-induced increase in intraneuronal calcium, which was essential for stimulated ROS formation. These results show that ADDLs bind to or in close proximity to NMDA-Rs, triggering neuronal damage through NMDA-R-dependent calcium flux. This response provides a pathologically specific mechanism for the therapeutic action of memantine, indicates a role for ROS dysregulation in ADDL-induced cognitive impairment, and supports the unifying hypothesis that ADDLs play a central role in AD pathogenesis.
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Affiliation(s)
- Fernanda G De Felice
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208, USA
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256
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Wu Y, Wu Z, Butko P, Christen Y, Lambert MP, Klein WL, Link CD, Luo Y. Amyloid-beta-induced pathological behaviors are suppressed by Ginkgo biloba extract EGb 761 and ginkgolides in transgenic Caenorhabditis elegans. J Neurosci 2007; 26:13102-13. [PMID: 17167099 PMCID: PMC6674971 DOI: 10.1523/jneurosci.3448-06.2006] [Citation(s) in RCA: 278] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Amyloid-beta (Abeta) toxicity has been postulated to initiate synaptic loss and subsequent neuronal degeneration seen in Alzheimer's disease (AD). We previously demonstrated that the standardized Ginkgo biloba extract EGb 761, commonly used to enhance memory and by AD patients for dementia, inhibits Abeta-induced apoptosis in neuroblastoma cells. In this study, we use EGb 761 and its single constituents to associate Abeta species with Abeta-induced pathological behaviors in a model organism, Caenorhabditis elegans. We report that EGb 761 and one of its components, ginkgolide A, alleviates Abeta-induced pathological behaviors, including paralysis, and reduces chemotaxis behavior and 5-HT hypersensitivity in a transgenic C. elegans. We also show that EGb 761 inhibits Abeta oligomerization and Abeta deposits in the worms. Moreover, reducing oxidative stress is not the mechanism by which EGb 761 and ginkgolide A suppress Abeta-induced paralysis because the antioxidant L-ascorbic acid reduced intracellular levels of hydrogen peroxide to the same extent as EGb 761, but was not nearly as effective in suppressing paralysis in the transgenic C. elegans. These findings suggest that (1) EGb 761 suppresses Abeta-related pathological behaviors, (2) the protection against Abeta toxicity by EGb 761 is mediated primarily by modulating Abeta oligomeric species, and (3) ginkgolide A has therapeutic potential for prevention and treatment of AD.
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Affiliation(s)
- Yanjue Wu
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
| | - Zhixin Wu
- Departments of Biological Sciences and
| | - Peter Butko
- Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, Mississippi 39406
| | | | - Mary P. Lambert
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208, and
| | - William L. Klein
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208, and
| | - Christopher D. Link
- Institute for Behavioral Genetics, University of Colorado, Boulder, Colorado 80309
| | - Yuan Luo
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201
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257
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Molecules that Disrupt Memory Circuits in Alzheimer’s Disease: The Attack on Synapses by Aβ Oligomers (ADDLs). MEMORIES: MOLECULES AND CIRCUITS 2007. [DOI: 10.1007/978-3-540-45702-2_11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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