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Amyloid β Oligomeric Species Present in the Lag Phase of Amyloid Formation. PLoS One 2015; 10:e0127865. [PMID: 26024352 PMCID: PMC4449029 DOI: 10.1371/journal.pone.0127865] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/20/2015] [Indexed: 12/29/2022] Open
Abstract
Alzheimer's disease (AD)-associated amyloid β peptide (Aβ) is one of the main actors in AD pathogenesis. Aβ is characterized by its high tendency to self-associate, leading to the generation of oligomers and amyloid fibrils. The elucidation of pathways and intermediates is crucial for the understanding of protein assembly mechanisms in general and in conjunction with neurodegenerative diseases, e.g., for the identification of new therapeutic targets. Our study focused on Aβ42 and its oligomeric assemblies in the lag phase of amyloid formation, as studied by sedimentation velocity (SV) centrifugation. The assembly state of Aβ during the lag phase, the time required by an Aβ solution to reach the exponential growth phase of aggregation, was characterized by a dominant monomer fraction below 1 S and a population of oligomeric species between 4 and 16 S. From the oligomer population, two major species close to a 12-mer and an 18-mer with a globular shape were identified. The recurrence of these two species at different initial concentrations and experimental conditions as the smallest assemblies present in solution supports the existence of distinct, energetically favored assemblies in solution. The sizes of the two species suggest an Aβ42 aggregation pathway that is based on a basic hexameric building block. The study demonstrates the potential of SV analysis for the evaluation of protein aggregation pathways.
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52
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Ferreira ST, Lourenco MV, Oliveira MM, De Felice FG. Soluble amyloid-β oligomers as synaptotoxins leading to cognitive impairment in Alzheimer's disease. Front Cell Neurosci 2015; 9:191. [PMID: 26074767 PMCID: PMC4443025 DOI: 10.3389/fncel.2015.00191] [Citation(s) in RCA: 236] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 04/30/2015] [Indexed: 12/22/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia in the elderly, and affects millions of people worldwide. As the number of AD cases continues to increase in both developed and developing countries, finding therapies that effectively halt or reverse disease progression constitutes a major research and public health challenge. Since the identification of the amyloid-β peptide (Aβ) as the major component of the amyloid plaques that are characteristically found in AD brains, a major effort has aimed to determine whether and how Aβ leads to memory loss and cognitive impairment. A large body of evidence accumulated in the past 15 years supports a pivotal role of soluble Aβ oligomers (AβOs) in synapse failure and neuronal dysfunction in AD. Nonetheless, a number of basic questions, including the exact molecular composition of the synaptotoxic oligomers, the identity of the receptor(s) to which they bind, and the signaling pathways that ultimately lead to synapse failure, remain to be definitively answered. Here, we discuss recent advances that have illuminated our understanding of the chemical nature of the toxic species and the deleterious impact they have on synapses, and have culminated in the proposal of an Aβ oligomer hypothesis for Alzheimer’s pathogenesis. We also highlight outstanding questions and challenges in AD research that should be addressed to allow translation of research findings into effective AD therapies.
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Affiliation(s)
- Sergio T Ferreira
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil ; Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
| | - Mychael V Lourenco
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
| | - Mauricio M Oliveira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
| | - Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro Rio de Janeiro, RJ, Brazil
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53
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Porzoor A, Alford B, Hügel HM, Grando D, Caine J, Macreadie I. Anti-amyloidogenic properties of some phenolic compounds. Biomolecules 2015; 5:505-27. [PMID: 25898401 PMCID: PMC4496683 DOI: 10.3390/biom5020505] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/02/2015] [Accepted: 04/03/2015] [Indexed: 12/23/2022] Open
Abstract
A family of 21 polyphenolic compounds consisting of those found naturally in danshen and their analogues were synthesized and subsequently screened for their anti-amyloidogenic activity against the amyloid beta peptide (Aβ42) of Alzheimer’s disease. After 24 h incubation with Aβ42, five compounds reduced thioflavin T (ThT) fluorescence, indicative of their anti-amyloidogenic propensity (p < 0.001). TEM and immunoblotting analysis also showed that selected compounds were capable of hindering fibril formation even after prolonged incubations. These compounds were also capable of rescuing the yeast cells from toxic changes induced by the chemically synthesized Aβ42. In a second assay, a Saccharomyces cerevisiae AHP1 deletant strain transformed with GFP fused to Aβ42 was treated with these compounds and analyzed by flow cytometry. There was a significant reduction in the green fluorescence intensity associated with 14 compounds. We interpret this result to mean that the compounds had an anti-amyloid-aggregation propensity in the yeast and GFP-Aβ42 was removed by proteolysis. The position and not the number of hydroxyl groups on the aromatic ring was found to be the most important determinant for the anti-amyloidogenic properties.
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Affiliation(s)
- Afsaneh Porzoor
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
| | - Benjamin Alford
- School of Applied Sciences, RMIT University, Melbourne, Victoria 3000, Australia.
| | - Helmut M Hügel
- School of Applied Sciences, RMIT University, Melbourne, Victoria 3000, Australia.
| | - Danilla Grando
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
| | - Joanne Caine
- Materials Science and Engineering, CSIRO Preventative Health Flagship, 343 Royal Parade, Parkville, Victoria 3052, Australia.
| | - Ian Macreadie
- School of Applied Sciences, RMIT University, Bundoora, Victoria 3083, Australia.
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Zeng Y, Zhang J, Zhu Y, Zhang J, Shen H, Lu J, Pan X, Lin N, Dai X, Zhou M, Chen X. Tripchlorolide improves cognitive deficits by reducing amyloid β and upregulating synapse-related proteins in a transgenic model of Alzheimer's Disease. J Neurochem 2015; 133:38-52. [DOI: 10.1111/jnc.13056] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 01/21/2015] [Accepted: 01/22/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Yuqi Zeng
- Department of Neurology and Geriatrics; Fujian Institute of Geriatrics; Fujian Medical University Union Hospital; Fuzhou China
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Jian Zhang
- Department of Neurology and Geriatrics; Fujian Institute of Geriatrics; Fujian Medical University Union Hospital; Fuzhou China
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Yuangui Zhu
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Jing Zhang
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Hui Shen
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Jianping Lu
- Department of Neurology and Geriatrics; Fujian Institute of Geriatrics; Fujian Medical University Union Hospital; Fuzhou China
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Xiaodong Pan
- Department of Neurology and Geriatrics; Fujian Institute of Geriatrics; Fujian Medical University Union Hospital; Fuzhou China
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Nan Lin
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Xiaoman Dai
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Meng Zhou
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Xiaochun Chen
- Department of Neurology and Geriatrics; Fujian Institute of Geriatrics; Fujian Medical University Union Hospital; Fuzhou China
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
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55
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Wang H. Fragile X mental retardation protein: from autism to neurodegenerative disease. Front Cell Neurosci 2015; 9:43. [PMID: 25729352 PMCID: PMC4325920 DOI: 10.3389/fncel.2015.00043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Accepted: 01/28/2015] [Indexed: 11/13/2022] Open
Affiliation(s)
- Hansen Wang
- Faculty of Medicine, University of Toronto Toronto, ON, Canada
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56
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Viola KL, Klein WL. Amyloid β oligomers in Alzheimer's disease pathogenesis, treatment, and diagnosis. Acta Neuropathol 2015; 129:183-206. [PMID: 25604547 DOI: 10.1007/s00401-015-1386-3] [Citation(s) in RCA: 430] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/11/2015] [Accepted: 01/11/2015] [Indexed: 12/22/2022]
Abstract
Protein aggregation is common to dozens of diseases including prionoses, diabetes, Parkinson's and Alzheimer's. Over the past 15 years, there has been a paradigm shift in understanding the structural basis for these proteinopathies. Precedent for this shift has come from investigation of soluble Aβ oligomers (AβOs), toxins now widely regarded as instigating neuron damage leading to Alzheimer's dementia. Toxic AβOs accumulate in AD brain and constitute long-lived alternatives to the disease-defining Aβ fibrils deposited in amyloid plaques. Key experiments using fibril-free AβO solutions demonstrated that while Aβ is essential for memory loss, the fibrillar Aβ in amyloid deposits is not the agent. The AD-like cellular pathologies induced by AβOs suggest their impact provides a unifying mechanism for AD pathogenesis, explaining why early stage disease is specific for memory and accounting for major facets of AD neuropathology. Alternative ideas for triggering mechanisms are being actively investigated. Some research favors insertion of AβOs into membrane, while other evidence supports ligand-like accumulation at particular synapses. Over a dozen candidate toxin receptors have been proposed. AβO binding triggers a redistribution of critical synaptic proteins and induces hyperactivity in metabotropic and ionotropic glutamate receptors. This leads to Ca(2+) overload and instigates major facets of AD neuropathology, including tau hyperphosphorylation, insulin resistance, oxidative stress, and synapse loss. Because different species of AβOs have been identified, a remaining question is which oligomer is the major pathogenic culprit. The possibility has been raised that more than one species plays a role. Despite some key unknowns, the clinical relevance of AβOs has been established, and new studies are beginning to point to co-morbidities such as diabetes and hypercholesterolemia as etiological factors. Because pathogenic AβOs appear early in the disease, they offer appealing targets for therapeutics and diagnostics. Promising therapeutic strategies include use of CNS insulin signaling enhancers to protect against the presence of toxins and elimination of the toxins through use of highly specific AβO antibodies. An AD-dependent accumulation of AβOs in CSF suggests their potential use as biomarkers and new AβO probes are opening the door to brain imaging. Overall, current evidence indicates that Aβ oligomers provide a substantive molecular basis for the cause, treatment and diagnosis of Alzheimer's disease.
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Scala F, Fusco S, Ripoli C, Piacentini R, Li Puma DD, Spinelli M, Laezza F, Grassi C, D'Ascenzo M. Intraneuronal Aβ accumulation induces hippocampal neuron hyperexcitability through A-type K(+) current inhibition mediated by activation of caspases and GSK-3. Neurobiol Aging 2015; 36:886-900. [PMID: 25541422 PMCID: PMC4801354 DOI: 10.1016/j.neurobiolaging.2014.10.034] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 10/14/2014] [Accepted: 10/24/2014] [Indexed: 11/20/2022]
Abstract
Amyloid β-protein (Aβ) pathologies have been linked to dysfunction of excitability in neurons of the hippocampal circuit, but the molecular mechanisms underlying this process are still poorly understood. Here, we applied whole-cell patch-clamp electrophysiology to primary hippocampal neurons and show that intracellular Aβ42 delivery leads to increased spike discharge and action potential broadening through downregulation of A-type K(+) currents. Pharmacologic studies showed that caspases and glycogen synthase kinase 3 (GSK-3) activation are required for these Aβ42-induced effects. Extracellular perfusion and subsequent internalization of Aβ42 increase spike discharge and promote GSK-3-dependent phosphorylation of the Kv4.2 α-subunit, a molecular determinant of A-type K(+) currents, at Ser-616. In acute hippocampal slices derived from an adult triple-transgenic Alzheimer's mouse model, characterized by endogenous intracellular accumulation of Aβ42, CA1 pyramidal neurons exhibit hyperexcitability accompanied by increased phosphorylation of Kv4.2 at Ser-616. Collectively, these data suggest that intraneuronal Aβ42 accumulation leads to an intracellular cascade culminating into caspases activation and GSK-3-dependent phosphorylation of Kv4.2 channels. These findings provide new insights into the toxic mechanisms triggered by intracellular Aβ42 and offer potentially new therapeutic targets for Alzheimer's disease treatment.
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Affiliation(s)
- Federico Scala
- Institute of Human Physiology, Medical School, Università Cattolica, Rome, Italy
| | - Salvatore Fusco
- Institute of Human Physiology, Medical School, Università Cattolica, Rome, Italy
| | - Cristian Ripoli
- Institute of Human Physiology, Medical School, Università Cattolica, Rome, Italy
| | - Roberto Piacentini
- Institute of Human Physiology, Medical School, Università Cattolica, Rome, Italy
| | | | - Matteo Spinelli
- Institute of Human Physiology, Medical School, Università Cattolica, Rome, Italy
| | - Fernanda Laezza
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
| | - Claudio Grassi
- Institute of Human Physiology, Medical School, Università Cattolica, Rome, Italy.
| | - Marcello D'Ascenzo
- Institute of Human Physiology, Medical School, Università Cattolica, Rome, Italy.
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58
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Pivtoraiko VN, Abrahamson EE, Leurgans SE, DeKosky ST, Mufson EJ, Ikonomovic MD. Cortical pyroglutamate amyloid-β levels and cognitive decline in Alzheimer's disease. Neurobiol Aging 2015; 36:12-9. [PMID: 25048160 PMCID: PMC4268150 DOI: 10.1016/j.neurobiolaging.2014.06.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 06/12/2014] [Accepted: 06/19/2014] [Indexed: 02/02/2023]
Abstract
Posterior cingulate cortex (PCC) accumulates amyloid-β (Aβ) early in Alzheimer's disease (AD). The relative concentrations of full-length Aβ and truncated, pyroglutamate-modified Aβ (NpE3) forms, and their correlations to cognitive dysfunction in AD, are unknown. We quantified AβNpE3-42, AβNpE3-40, Aβ1-42, and Aβ1-40 concentrations in soluble (nonfibrillar) and insoluble (fibrillar) pools in PCC from subjects with an antemortem clinical diagnosis of no cognitive impairment, mild cognitive impairment, or mild-moderate AD. In clinical AD, increased PCC concentrations of Aβ were observed for all Aβ forms in the insoluble pool but only for Aβ1-42 in the soluble pool. Lower Mini-Mental State Exam and episodic memory scores correlated most strongly with higher concentrations of soluble and insoluble Aβ1-42. Greater neuropathology severity by Consortium to Establish a Registry for Alzheimer's Disease and National Institute on Aging-Reagan pathologic criteria was associated with higher concentrations of all measured Aβ forms, except soluble AβNpE3-40. Low concentrations of soluble pyroglutamate Aβ across clinical groups likely reflect its rapid sequestration into plaques, thus, the conversion to fibrillar Aβ may be a therapeutic target.
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Affiliation(s)
| | - Eric E Abrahamson
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA; Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, USA
| | - Sue E Leurgans
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL
| | - Steven T DeKosky
- Department of Neurology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Elliott J Mufson
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Milos D Ikonomovic
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA; Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, USA; Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA.
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59
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Qi Y, Klyubin I, Harney SC, Hu N, Cullen WK, Grant MK, Steffen J, Wilson EN, Do Carmo S, Remy S, Fuhrmann M, Ashe KH, Cuello AC, Rowan MJ. Longitudinal testing of hippocampal plasticity reveals the onset and maintenance of endogenous human Aß-induced synaptic dysfunction in individual freely behaving pre-plaque transgenic rats: rapid reversal by anti-Aß agents. Acta Neuropathol Commun 2014; 2:175. [PMID: 25540024 PMCID: PMC4293804 DOI: 10.1186/s40478-014-0175-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 12/04/2014] [Indexed: 11/26/2022] Open
Abstract
Long before synaptic loss occurs in Alzheimer’s disease significant harbingers of disease may be detected at the functional level. Here we examined if synaptic long-term potentiation is selectively disrupted prior to extracellular deposition of Aß in a very complete model of Alzheimer’s disease amyloidosis, the McGill-R-Thy1-APP transgenic rat. Longitudinal studies in freely behaving animals revealed an age-dependent, relatively rapid-onset and persistent inhibition of long-term potentiation without a change in baseline synaptic transmission in the CA1 area of the hippocampus. Thus the ability of a standard 200 Hz conditioning protocol to induce significant NMDA receptor-dependent short- and long-term potentiation was lost at about 3.5 months of age and this deficit persisted for at least another 2–3 months, when plaques start to appear. Consistent with in vitro evidence for a causal role of a selective reduction in NMDA receptor-mediated synaptic currents, the deficit in synaptic plasticity in vivo was associated with a reduction in the synaptic burst response to the conditioning stimulation and was overcome using stronger 400 Hz stimulation. Moreover, intracerebroventricular treatment for 3 days with an N-terminally directed monoclonal anti- human Aß antibody, McSA1, transiently reversed the impairment of synaptic plasticity. Similar brief treatment with the BACE1 inhibitor LY2886721 or the γ-secretase inhibitor MRK-560 was found to have a comparable short-lived ameliorative effect when tracked in individual rats. These findings provide strong evidence that endogenously generated human Aß selectively disrupts the induction of long-term potentiation in a manner that enables potential therapeutic options to be assessed longitudinally at the pre-plaque stage of Alzheimer’s disease amyloidosis.
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60
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Ghilan M, Bostrom CA, Hryciw BN, Simpson JM, Christie BR, Gil-Mohapel J. YAC128 Huntington׳s disease transgenic mice show enhanced short-term hippocampal synaptic plasticity early in the course of the disease. Brain Res 2014; 1581:117-28. [DOI: 10.1016/j.brainres.2014.06.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 05/02/2014] [Accepted: 06/07/2014] [Indexed: 01/31/2023]
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Chang L, Li F, Chen X, Xu S, Wang C, Chen H, Wang Q. Effects of acidic oligosaccharide sugar chain on amyloid oligomer-induced impairment of synaptic plasticity in rats. Metab Brain Dis 2014; 29:683-90. [PMID: 24723110 DOI: 10.1007/s11011-014-9521-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 02/26/2014] [Indexed: 10/25/2022]
Abstract
Soluble amyloid-β protein (Aβ) oligomers have been recognized to be early and key intermediates in Alzheimer's disease-related synaptic dysfunction. In this study, using in vitro electrophysiology, we investigated interactions of the acidic oligosaccharide sugar chain (AOSC), a marine-derived acidic oligosaccharide, with oligomeric Aβ. We found that the inhibition of long-term potentiation (LTP) induced by Aβ oligomers can be dose dependently reversed by the application of AOSC, whereas AOSC alone did not alter normal LTP induction. Interestingly, treatment with Aβ monomers with or without AOSC did not affect LTP induction. Additionally, when fresh-made Aβ was co-incubated with AOSC before in vitro testing, there was no impairment of LTP induction. The results from Western blots demonstrated that AOSC prevent the aggregation of Aβ oligomers. These findings indicate that AOSC may reverse Aβ oligomer-mediated cytotoxicity by directly disrupting the amyloid oligomer aggregation, and this action is concentration dependent. Thus, we propose that AOSC might be a potential therapeutic drug for Alzheimer's disease due to its protection against oligomeric Aβ-induced dysfunction of synaptic plasticity.
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Affiliation(s)
- Lan Chang
- Zhejiang Provincial Key Laboratory of Pathophysiology, Medical School, Ningbo University, Ningbo, 315211, China,
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Mattsson N, Insel PS, Nosheny R, Tosun D, Trojanowski JQ, Shaw LM, Jack CR, Donohue MC, Weiner MW. Emerging β-amyloid pathology and accelerated cortical atrophy. JAMA Neurol 2014; 71:725-34. [PMID: 24781145 DOI: 10.1001/jamaneurol.2014.446] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE The effect of β-amyloid (Aβ) accumulation on regional structural brain changes in early stages of Alzheimer disease (AD) is not well understood. OBJECTIVE To test the hypothesis that the development of Aβ pathology is related to increased regional atrophy in the brains of cognitively normal (CN) persons. DESIGN, SETTING, AND PARTICIPANTS Longitudinal clinicobiomarker cohort study involving 47 CN control subjects and 15 patients with AD dementia. All participants underwent repeated cerebrospinal fluid Aβ42 and structural magnetic resonance imaging measurements for up to 4 years. Cognitively normal controls were classified using the longitudinal cerebrospinal fluid Aβ42 data and included 13 stable Aβ negative (normal baseline Aβ42 levels, with less than the median reduction over time), 13 declining Aβ negative (normal baseline Aβ42 levels, with greater than the median reduction over time), and 21 Aβ positive (pathologic baseline Aβ42 levels). All 15 patients with AD dementia were Aβ positive. MAIN OUTCOMES AND MEASURES Group effects on regional gray matter volumes at baseline and over time, tested by linear mixed-effects models. RESULTS Baseline gray matter volumes were similar among the CN Aβ groups, but atrophy rates were increased in frontoparietal regions in the declining Aβ-negative and Aβ-positive groups and in amygdala and temporal regions in the Aβ-positive group. Aβ-positive patients with AD dementia had further increased atrophy rates in hippocampus and temporal and cingulate regions. CONCLUSIONS AND RELEVANCE Emerging Aβ pathology is coupled to increased frontoparietal (but not temporal) atrophy rates. Atrophy rates peak early in frontoparietal regions but accelerate in hippocampus, temporal, and cingulate regions as the disease progresses to dementia. Early-stage Aβ pathology may have mild effects on local frontoparietal cortical integrity while effects in temporal regions appear later and accelerate, leading to the atrophy pattern typically seen in AD.
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Affiliation(s)
- Niklas Mattsson
- Department of Veterans Affairs Medical Center, Center for Imaging of Neurodegenerative Diseases, San Francisco, California2Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Möl
| | - Philip S Insel
- Department of Veterans Affairs Medical Center, Center for Imaging of Neurodegenerative Diseases, San Francisco, California3Department of Radiology and Biomedical Imaging, University of California, San Francisco
| | - Rachel Nosheny
- Department of Veterans Affairs Medical Center, Center for Imaging of Neurodegenerative Diseases, San Francisco, California
| | - Duygu Tosun
- Department of Veterans Affairs Medical Center, Center for Imaging of Neurodegenerative Diseases, San Francisco, California3Department of Radiology and Biomedical Imaging, University of California, San Francisco
| | - John Q Trojanowski
- Department of Pathology and Laboratory Medicine, Institute on Aging, Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Leslie M Shaw
- Department of Pathology and Laboratory Medicine, Institute on Aging, Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | | | - Michael C Donohue
- Division of Biostatistics and Bioinformatics, Department of Family and Preventive Medicine, University of California, San Diego, La Jolla
| | - Michael W Weiner
- Department of Veterans Affairs Medical Center, Center for Imaging of Neurodegenerative Diseases, San Francisco, California3Department of Radiology and Biomedical Imaging, University of California, San Francisco
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Goure WF, Krafft GA, Jerecic J, Hefti F. Targeting the proper amyloid-beta neuronal toxins: a path forward for Alzheimer's disease immunotherapeutics. ALZHEIMERS RESEARCH & THERAPY 2014; 6:42. [PMID: 25045405 PMCID: PMC4100318 DOI: 10.1186/alzrt272] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Levels of amyloid-beta monomer and deposited amyloid-beta in the Alzheimer’s
disease brain are orders of magnitude greater than soluble amyloid-beta oligomer
levels. Monomeric amyloid-beta has no known direct toxicity. Insoluble fibrillar
amyloid-beta has been proposed to be an in vivo mechanism for removal of
soluble amyloid-beta and exhibits relatively low toxicity. In contrast, soluble
amyloid-beta oligomers are widely reported to be the most toxic amyloid-beta form,
both causing acute synaptotoxicity and inducing neurodegenerative processes. None of
the amyloid-beta immunotherapies currently in clinical development selectively target
soluble amyloid-beta oligomers, and their lack of efficacy is not unexpected
considering their selectivity for monomeric or fibrillar amyloid-beta (or both)
rather than soluble amyloid-beta oligomers. Because they exhibit acute,
memory-compromising synaptic toxicity and induce chronic neurodegenerative toxicity
and because they exist at very low in vivo levels in the Alzheimer’s
disease brain, soluble amyloid-beta oligomers constitute an optimal immunotherapeutic
target that should be pursued more aggressively.
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Affiliation(s)
- William F Goure
- Acumen Pharmaceuticals, Inc., 4453 North First Street, #360, Livermore, CA 94551, USA
| | - Grant A Krafft
- Acumen Pharmaceuticals, Inc., 4453 North First Street, #360, Livermore, CA 94551, USA
| | - Jasna Jerecic
- Acumen Pharmaceuticals, Inc., 4453 North First Street, #360, Livermore, CA 94551, USA
| | - Franz Hefti
- Acumen Pharmaceuticals, Inc., 4453 North First Street, #360, Livermore, CA 94551, USA
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Sitkiewicz E, Kłoniecki M, Poznański J, Bal W, Dadlez M. Factors Influencing Compact–Extended Structure Equilibrium in Oligomers of Aβ1–40 Peptide—An Ion Mobility Mass Spectrometry Study. J Mol Biol 2014; 426:2871-85. [DOI: 10.1016/j.jmb.2014.05.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 05/08/2014] [Accepted: 05/15/2014] [Indexed: 12/15/2022]
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65
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Sitkiewicz E, Olędzki J, Poznański J, Dadlez M. Di-tyrosine cross-link decreases the collisional cross-section of aβ peptide dimers and trimers in the gas phase: an ion mobility study. PLoS One 2014; 9:e100200. [PMID: 24945725 PMCID: PMC4063900 DOI: 10.1371/journal.pone.0100200] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 05/22/2014] [Indexed: 01/04/2023] Open
Abstract
Oligomeric forms of Aβ peptide are most likely the main synaptotoxic and neurotoxic agent in Alzheimer’s disease. Toxicity of various Aβ oligomeric forms has been confirmed in vivo and also in vitro. However, in vitro preparations were found to be orders of magnitude less toxic than oligomers obtained from in vivo sources. This difference can be explained by the presence of a covalent cross-link, which would stabilize the oligomer. In the present work, we have characterized the structural properties of Aβ dimers and trimers stabilized by di- and tri-tyrosine cross-links. Using ion mobility mass spectrometry we have compared the collisional cross-section of non-cross-linked and cross-linked species. We have found that the presence of cross-links does not generate new unique forms but rather shifts the equilibrium towards more compact oligomer types that can also be detected for non-cross-linked peptide. In consequence, more extended forms, probable precursors of off-pathway oligomeric species, become relatively destabilized in cross-linked oligomers and the pathway of oligomer evolution becomes redirected towards fibrillar structures.
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Affiliation(s)
- Ewa Sitkiewicz
- Institute of Biochemistry and Biophysics, Polish Academy of Science, Warszawa, Poland
| | - Jacek Olędzki
- Institute of Biochemistry and Biophysics, Polish Academy of Science, Warszawa, Poland
| | - Jarosław Poznański
- Institute of Biochemistry and Biophysics, Polish Academy of Science, Warszawa, Poland
| | - Michał Dadlez
- Institute of Biochemistry and Biophysics, Polish Academy of Science, Warszawa, Poland
- Institute of Genetics and Biotechnology, Biology Department, Warsaw University, Warszawa, Poland
- * E-mail:
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Liu MG, Chen J. Preclinical research on pain comorbidity with affective disorders and cognitive deficits: Challenges and perspectives. Prog Neurobiol 2014; 116:13-32. [DOI: 10.1016/j.pneurobio.2014.01.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 12/31/2013] [Accepted: 01/02/2014] [Indexed: 12/12/2022]
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Dal Prà I, Chiarini A, Gui L, Chakravarthy B, Pacchiana R, Gardenal E, Whitfield JF, Armato U. Do astrocytes collaborate with neurons in spreading the "infectious" aβ and Tau drivers of Alzheimer's disease? Neuroscientist 2014; 21:9-29. [PMID: 24740577 DOI: 10.1177/1073858414529828] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Evidence has begun emerging for the "contagious" and destructive Aβ42 (amyloid-beta42) oligomers and phosphorylated Tau oligomers as drivers of sporadic Alzheimer's disease (AD), which advances along a pathway starting from the brainstem or entorhinal cortex and leading to cognition-related upper cerebral cortex regions. Seemingly, Aβ42 oligomers trigger the events generating the neurotoxic Tau oligomers, which may even by themselves spread the characteristic AD neuropathology. It has been assumed that only neurons make and spread these toxic drivers, whereas their associated astrocytes are just janitorial bystanders/scavengers. But this view is likely to radically change since normal human astrocytes freshly isolated from adult cerebral cortex can be induced by exogenous Aβ25-35, an Aβ42 proxy, to make and secrete increased amounts of endogenous Aβ42. Thus, it would seem that the steady slow progression of AD neuropathology along specific cognition-relevant brain networks is driven by both Aβ42 and phosphorylated Tau oligomers that are variously released from increasing numbers of "contagion-stricken" members of tightly coupled neuron-astrocyte teams. Hence, we surmise that stopping the oversecretion and spread of the two kinds of "contagious" oligomers by such team members, perhaps via a specific CaSR (Ca(2+)-sensing receptor) antagonist like NPS 2143, might effectively treat AD.
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Affiliation(s)
- Ilaria Dal Prà
- Department of Life & Reproduction Sciences, The University of Verona Medical School, Verona, Italy
| | - Anna Chiarini
- Department of Life & Reproduction Sciences, The University of Verona Medical School, Verona, Italy
| | - Li Gui
- Department of Neurology, Southwest Hospital, Third Military Medical University, Chongqing, China
| | | | - Raffaella Pacchiana
- Department of Life & Reproduction Sciences, The University of Verona Medical School, Verona, Italy
| | - Emanuela Gardenal
- Department of Life & Reproduction Sciences, The University of Verona Medical School, Verona, Italy
| | | | - Ubaldo Armato
- Department of Life & Reproduction Sciences, The University of Verona Medical School, Verona, Italy
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68
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Hottman DA, Li L. Protein prenylation and synaptic plasticity: implications for Alzheimer's disease. Mol Neurobiol 2014; 50:177-85. [PMID: 24390573 DOI: 10.1007/s12035-013-8627-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 12/20/2013] [Indexed: 12/11/2022]
Abstract
Protein prenylation is an important lipid posttranslational modification of proteins. It includes protein farnesylation and geranylgeranylation, in which the 15-carbon farnesyl pyrophosphate or 20-carbon geranylgeranyl pyrophosphate is attached to the C-terminus of target proteins, catalyzed by farnesyl transferase or geranylgeranyl transferases, respectively. Protein prenylation facilitates the anchoring of proteins into the cell membrane and mediates protein-protein interactions. Among numerous proteins that undergo prenylation, small GTPases represent the largest group of prenylated proteins. Small GTPases are involved in regulating a plethora of cellular functions including synaptic plasticity. The prenylation status of small GTPases determines the subcellular locations and functions of the proteins. Dysregulation or dysfunction of small GTPases leads to the development of different types of disorders. Emerging evidence indicates that prenylated proteins, in particular small GTPases, may play important roles in the pathogenesis of Alzheimer's disease. This review focuses on the prenylation of Ras and Rho subfamilies of small GTPases and its relation to synaptic plasticity and Alzheimer's disease.
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Affiliation(s)
- David A Hottman
- Department of Experimental and Clinical Pharmacology, University of Minnesota, 2001 6th St SE, MTRF 4-208, Minneapolis, MN, 55455, USA
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69
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Tan MGK, Lee C, Lee JH, Francis PT, Williams RJ, Ramírez MJ, Chen CP, Wong PTH, Lai MKP. Decreased rabphilin 3A immunoreactivity in Alzheimer's disease is associated with Aβ burden. Neurochem Int 2014; 64:29-36. [PMID: 24200817 DOI: 10.1016/j.neuint.2013.10.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 10/12/2013] [Accepted: 10/28/2013] [Indexed: 11/22/2022]
Abstract
Synaptic dysfunction, together with neuritic plaques, neurofibrillary tangles and cholinergic neuron loss is an established finding in the Alzheimer's disease (AD) neocortex. The synaptopathology of AD is known to involve both pre- and postsynaptic components. However, the status of rabphilin 3A (RPH3A), which interacts with the SNARE complex and regulates synaptic vesicle exocytosis and Ca(2+)-triggered neurotransmitter release, is at present unclear. In this study, we measured RPH3A and its ligand Rab3A as well as several SNARE proteins in postmortem neocortex of patients with AD, and found specific reductions of RPH3A immunoreactivity compared with aged controls. RPH3A loss correlated with dementia severity, cholinergic deafferentation, and increased β-amyloid (Aβ) concentrations. Furthermore, RPH3A expression is selectively downregulated in cultured neurons treated with Aβ25-35 peptides. Our data suggest that presynaptic SNARE dysfunction forms part of the synaptopathology of AD.
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Affiliation(s)
- Michelle G K Tan
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Clinical Research, Singapore General Hospital, Singapore
| | - Chingli Lee
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Jasinda H Lee
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Paul T Francis
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK
| | - Robert J Williams
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - María J Ramírez
- Department of Pharmacology, School of Medicine, Centre for Applied Medical Research, University of Navarra, Pamplona, Spain
| | - Christopher P Chen
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Memory, Aging and Cognition Centre (MACC), National University Health System, Singapore
| | - Peter T-H Wong
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Memory, Aging and Cognition Centre (MACC), National University Health System, Singapore
| | - Mitchell K P Lai
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Memory, Aging and Cognition Centre (MACC), National University Health System, Singapore.
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Tripchlorolide improves age-associated cognitive deficits by reversing hippocampal synaptic plasticity impairment and NMDA receptor dysfunction in SAMP8 mice. Behav Brain Res 2014; 258:8-18. [DOI: 10.1016/j.bbr.2013.10.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 09/29/2013] [Accepted: 10/03/2013] [Indexed: 02/02/2023]
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72
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An K, Klyubin I, Kim Y, Jung JH, Mably AJ, O'Dowd ST, Lynch T, Kanmert D, Lemere CA, Finan GM, Park JW, Kim TW, Walsh DM, Rowan MJ, Kim JH. Exosomes neutralize synaptic-plasticity-disrupting activity of Aβ assemblies in vivo. Mol Brain 2013; 6:47. [PMID: 24284042 PMCID: PMC4222117 DOI: 10.1186/1756-6606-6-47] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 10/31/2013] [Indexed: 12/28/2022] Open
Abstract
Background Exosomes, small extracellular vesicles of endosomal origin, have been suggested to be involved in both the metabolism and aggregation of Alzheimer’s disease (AD)-associated amyloid β-protein (Aβ). Despite their ubiquitous presence and the inclusion of components which can potentially interact with Aβ, the role of exosomes in regulating synaptic dysfunction induced by Aβ has not been explored. Results We here provide in vivo evidence that exosomes derived from N2a cells or human cerebrospinal fluid can abrogate the synaptic-plasticity-disrupting activity of both synthetic and AD brain-derived Aβ. Mechanistically, this effect involves sequestration of synaptotoxic Aβ assemblies by exosomal surface proteins such as PrPC rather than Aβ proteolysis. Conclusions These data suggest that exosomes can counteract the inhibitory action of Aβ, which contributes to perpetual capability for synaptic plasticity.
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Affiliation(s)
- Kyongman An
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, Gyungbuk 790-784, Korea.
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Hong X, Liu J, Zhu G, Zhuang Y, Suo H, Wang P, Huang D, Xu J, Huang Y, Yu M, Bian M, Sheng Z, Fei J, Song H, Behnisch T, Huang F. Parkin overexpression ameliorates hippocampal long-term potentiation and β-amyloid load in an Alzheimer's disease mouse model. Hum Mol Genet 2013; 23:1056-72. [PMID: 24105468 DOI: 10.1093/hmg/ddt501] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by a severe decline of memory performance. A widely studied AD mouse model is the APPswe/PSEN1ΔE9 (APP/PS1) strain, as mice exhibit amyloid plaques as well as impaired memory capacities. To test whether restoring synaptic plasticity and decreasing β-amyloid load by Parkin could represent a potential therapeutic target for AD, we crossed APP/PS1 transgenic mice with transgenic mice overexpressing the ubiquitin ligase Parkin and analyzed offspring properties. Overexpression of Parkin in APP/PS1 transgenic mice restored activity-dependent synaptic plasticity and rescued behavioral abnormalities. Moreover, overexpression of Parkin was associated with down-regulation of APP protein expression, decreased β-amyloid load and reduced inflammation. Our data suggest that Parkin could be a promising target for AD therapy.
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Affiliation(s)
- Xiaoqi Hong
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Shanghai Medical College, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
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Wu WH, Liu Q, Sun X, Yu JS, Zhao DS, Yu YP, Luo JJ, Hu J, Yu ZW, Zhao YF, Li YM. Fibrillar seeds alleviate amyloid-β cytotoxicity by omitting formation of higher-molecular-weight oligomers. Biochem Biophys Res Commun 2013; 439:321-6. [PMID: 24012671 DOI: 10.1016/j.bbrc.2013.08.088] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 08/28/2013] [Indexed: 11/20/2022]
Abstract
Amyloid-β (Aβ) peptides can exist in distinct forms including monomers, oligomers and fibrils, consisting of increased numbers of monomeric units. Among these, Aβ oligomers are implicated as the primary toxic species as pointed by multiple lines of evidence. It has been suggested that toxicity could be rendered by the soluble higher-molecular-weight (high-n) Aβ oligomers. Yet, the most culpable form in the pathogenesis of Alzheimer's disease (AD) remains elusive. Moreover, the potential interaction among the insoluble fibrils that have been excluded from the responsible aggregates in AD development, Aβ monomers and high-n oligomers is undetermined. Here, we report that insoluble Aβ fibrillar seeds can interact with Aβ monomers at the stoichiometry of 1:2 (namely, each Aβ molecule of seed can bind to two Aβ monomers at a time) facilitating the fibrillization by omitting the otherwise mandatory formation of the toxic high-n oligomers during the fibril maturation. As a result, the addition of exogenous Aβ fibrillar seeds is seen to rescue neuronal cells from Aβ cytotoxicity presumably exerted by high-n oligomers, suggesting an unexpected protective role of Aβ fibrillar seeds.
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Affiliation(s)
- Wei-hui Wu
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, PR China; Institute of Chemical Defence, Beijing 102205, PR China
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Hefti F, Goure WF, Jerecic J, Iverson KS, Walicke PA, Krafft GA. The case for soluble Aβ oligomers as a drug target in Alzheimer's disease. Trends Pharmacol Sci 2013; 34:261-6. [DOI: 10.1016/j.tips.2013.03.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 03/08/2013] [Accepted: 03/12/2013] [Indexed: 10/27/2022]
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