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Lord A, Philipson O, Klingstedt T, Westermark G, Hammarström P, Nilsson KPR, Nilsson LNG. Observations in APP bitransgenic mice suggest that diffuse and compact plaques form via independent processes in Alzheimer's disease. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2286-98. [PMID: 21514441 DOI: 10.1016/j.ajpath.2011.01.052] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 01/04/2011] [Accepted: 01/13/2011] [Indexed: 11/26/2022]
Abstract
Studies of familial Alzheimer's disease suggest that misfolding and aggregation of amyloid-β (Aβ) peptides initiate the pathogenesis. The Arctic mutation of Aβ precursor protein (APP) results in AD, and Arctic Aβ is more prone to form Aβ protofibrils and extracellular deposits. Herein is demonstrated that the burden of diffuse Aβ deposits but not compact plaques is increased when tg-Swe mice are crossed with tg-ArcSwe mice synthesizing low levels of Arctic Aβ. The diffuse deposits in bitransgenic mice, which contain primarily wild-type Aβ42, accumulate in regions both with and without transgene expression. However, APP processing, when compared with tg-Swe, remains unchanged in young bitransgenic mice, whereas wild-type Aβ42 aggregation is accelerated and fibril architecture is altered in vitro and in vivo when a low level of Arctic Aβ42 is introduced. Thus, the increased number of diffuse deposits is likely due to physical interactions between Arctic Aβ and wild-type Aβ42. The selective increase of a single type of parenchymal Aβ deposit suggests that different pathways lead to formation of diffuse and compact plaques. These findings could have general implications for Alzheimer's disease pathogenesis and particular relevance to patients heterozygous for the Arctic APP mutation. Moreover, it further illustrates how Aβ neuropathologic features can be manipulated in vivo by mechanisms similar to those originally conceptualized in prion research.
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Affiliation(s)
- Anna Lord
- Department of Public Health and Caring Sciences/Molecular Geriatrics, Uppsala University, Uppsala, Sweden
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152
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Roher AE, Maarouf CL, Daugs ID, Kokjohn TA, Hunter JM, Sabbagh MN, Beach TG. Neuropathology and amyloid-β spectrum in a bapineuzumab immunotherapy recipient. J Alzheimers Dis 2011; 24:315-25. [PMID: 21263194 DOI: 10.3233/jad-2011-101809] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The field of Alzheimer's disease (AD) research eagerly awaits the results of a large number of Phase III clinical trials that are underway to investigate the effectiveness of anti-amyloid-β (Aβ) immunotherapy for AD. In this case report, we review the pertinent clinical history, examine the neuropathology, and characterize the Aβ profile of an AD patient who received bapineuzumab immunotherapy. The patient received four bapineuzumab infusions over a 39 week period. During the course of this treatment, there was no remarkable change in cognitive impairment as determined by MMSE scores. Forty-eight days after the fourth bapineuzumab infusion was given, MRI revealed that the patient had developed lacunar infarcts and possible vasogenic edema, probably related to immunotherapy, but a subsequent MRI scan 38 days later demonstrated resolution of vasogenic edema. The patient expired due to acute congestive heart failure complicated by progressive AD and cerebrovascular accident 378 days after the first bapineuzumab infusion and 107 days after the end of therapy. Neuropathological and biochemical analysis did not produce evidence of lasting plaque regression or clearance of Aβ due to immunotherapy. The Aβ species profile of this case was compared with non-immunized AD cases and non-demented controls and found to be similar to non-immunized AD cases. SELDI-TOF mass spectrometric analysis revealed the presence of full-length Aβ₁₋₄₂ and truncated Aβ peptides demonstrating species with and without bapineuzumab specific epitopes. These results suggest that, in this particular case, bapineuzumab immunotherapy neither resulted in detectable clearance of amyloid plaques nor prevented further cognitive impairment.
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Affiliation(s)
- Alex E Roher
- Longtine Center for Neurodegenerative Biochemistry, Banner Sun Health Research Institute, Sun City, AZ 85351, USA.
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153
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Zotova E, Holmes C, Johnston D, Neal JW, Nicoll JAR, Boche D. Microglial alterations in human Alzheimer's disease following Aβ42 immunization. Neuropathol Appl Neurobiol 2011; 37:513-24. [PMID: 21166690 DOI: 10.1111/j.1365-2990.2010.01156.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
AIMS In Alzheimer's disease (AD), microglial activation prompted by the presence of amyloid has been proposed as an important contributor to the neurodegenerative process. Conversely following Aβ immunization, phagocytic microglia have been implicated in plaque removal, potentially a beneficial effect. We have investigated the effects of Aβ42 immunization on microglial activation and the relationship with Aβ42 load in human AD. METHODS Immunostaining against Aβ42 and microglia (CD68 and HLA-DR) was performed in nine immunized AD cases (iAD - AN1792, Elan Pharmaceuticals) and eight unimmunized AD (cAD) cases. RESULTS Although the Aβ42 load (% area stained of total area examined) was lower in the iAD than the cAD cases (P=0.036), the CD68 load was higher (P=0.046). In addition, in the iAD group, the CD68 level correlated with the Aβ42 load, consistent with the immunization upregulating microglial phagocytosis when plaques are present. However, in two long-surviving iAD patients in whom plaques had been extensively cleared, the CD68 load was less than in controls. HLA-DR quantification did not show significant difference implying that the microglial activation may have related specifically to their phagocytic function. CD68 and HLA-DR loads in the pons were similar in both groups, suggesting that the differences in microglial activation in the cortex were due to the presence of AD pathology. CONCLUSION Our findings suggest that Aβ42 immunization modifies the function of microglia by increasing their phagocytic activity and when plaques have been cleared, the level of phagocytosis is decreased below that seen in unimmunized AD.
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MESH Headings
- Aged
- Aged, 80 and over
- Alzheimer Disease/immunology
- Alzheimer Disease/pathology
- Alzheimer Disease/therapy
- Alzheimer Vaccines/immunology
- Amyloid beta-Peptides/immunology
- Amyloid beta-Peptides/therapeutic use
- Amyloid beta-Protein Precursor/metabolism
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Antigens, Differentiation, Myelomonocytic/immunology
- Antigens, Differentiation, Myelomonocytic/metabolism
- Brain/immunology
- Brain/metabolism
- Brain/pathology
- Clinical Trials, Phase I as Topic
- Female
- Humans
- Immunohistochemistry
- Male
- Microglia/immunology
- Microglia/metabolism
- Microscopy, Confocal
- Middle Aged
- Plaque, Amyloid/pathology
- Plaque, Amyloid/therapy
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Affiliation(s)
- E Zotova
- Division of Clinical Neurosciences, School of Medicine, University of Southampton, UK.
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154
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Hsiao YH, Chen PS, Chen SH, Gean PW. The involvement of Cdk5 activator p35 in social isolation-triggered onset of early Alzheimer's disease-related cognitive deficit in the transgenic mice. Neuropsychopharmacology 2011; 36:1848-58. [PMID: 21544067 PMCID: PMC3154103 DOI: 10.1038/npp.2011.69] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epidemiological studies indicate that isolated persons have increased risk of developing Alzheimer's disease (AD). This study investigated the cellular mechanisms of how social isolation influenced amyloid β peptide (Aβ) accumulation and affected the severity of AD-associated cognitive decline in a mouse model of AD. Amyloid precursor protein (APP) and presenilin 1 (PS1) double-transgenic (APP/PS1) mice were placed either in isolation or in group from postnatal day 28 and tested for cognitive performance at the age of 3 months with fear-conditioning paradigms. We found that social isolation accelerated impairment of contextual fear memory in the APP/PS1 mice. The magnitude of long-term potentiation in the hippocampal CA1 neurons was significantly lower in the isolated APP/PS1 mice compared with group APP/PS1 and wild-type mice. Hippocampal level of Aβ was significantly elevated in the isolated APP/PS1 mice, which was accompanied by an increased calpain activity and p25/p35 ratio. In addition, surface expression of GluR1 subunit of AMPA receptor was decreased by social isolation. The association of p35, and α-CaMKII was significantly less in the isolated APP/PS1 mice indicating that their interaction was impaired. These results suggest that social isolation exacerbates memory deficit by increasing Aβ level, leading to the increased calpain activity, conversion of p35 to p25 and decrease in association of p35, α-CaMKII, and GluR1, resulting in the endocytosis of AMPA receptors.
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Affiliation(s)
- Ya-Hsin Hsiao
- Institute of Basic Medical Sciences and Department of Pharmacology, Center for Gene Regulation and Signal Transduction Research, National Cheng-Kung University, Tainan, Taiwan
| | - Po See Chen
- Institute of Basic Medical Sciences and Department of Pharmacology, Center for Gene Regulation and Signal Transduction Research, National Cheng-Kung University, Tainan, Taiwan
| | - Shun-Hua Chen
- Institute of Basic Medical Sciences and Department of Pharmacology, Center for Gene Regulation and Signal Transduction Research, National Cheng-Kung University, Tainan, Taiwan
| | - Po-Wu Gean
- Institute of Basic Medical Sciences and Department of Pharmacology, Center for Gene Regulation and Signal Transduction Research, National Cheng-Kung University, Tainan, Taiwan,Department of Pharmacology, College of Medicine, No.1 University Road, National Cheng-Kung University, Tainan 701, Taiwan, Tel: +886 6 2353535 ext. 5507, Fax: +886 6 2749296, E-mail:
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155
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Cho SH, Sun B, Zhou Y, Kauppinen TM, Halabisky B, Wes P, Ransohoff RM, Gan L. CX3CR1 protein signaling modulates microglial activation and protects against plaque-independent cognitive deficits in a mouse model of Alzheimer disease. J Biol Chem 2011; 286:32713-22. [PMID: 21771791 DOI: 10.1074/jbc.m111.254268] [Citation(s) in RCA: 195] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Aberrant microglial activation has been proposed to contribute to the cognitive decline in Alzheimer disease (AD), but the underlying molecular mechanisms remain enigmatic. Fractalkine signaling, a pathway mediating the communication between microglia and neurons, is deficient in AD brains and down-regulated by amyloid-β. Although fractalkine receptor (CX3CR1) on microglia was found to regulate plaque load, no functional effects have been reported. Our study demonstrates that CX3CR1 deficiency worsens the AD-related neuronal and behavioral deficits. The effects were associated with cytokine production but not with plaque deposition. Ablation of CX3CR1 in mice overexpressing human amyloid precursor protein enhanced Tau pathology and exacerbated the depletion of calbindin in the dentate gyrus. The levels of calbindin in the dentate gyrus correlated negatively with those of tumor necrosis factor α and interleukin 6, suggesting neurotoxic effects of inflammatory factors. Functionally, removing CX3CR1 in human amyloid precursor protein mice worsened the memory retention in passive avoidance and novel object recognition tests, and their memory loss in the novel object recognition test is associated with high levels of interleukin 6. Our findings identify CX3CR1 as a key microglial pathway in protecting against AD-related cognitive deficits that are associated with aberrant microglial activation and elevated inflammatory cytokines.
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Affiliation(s)
- Seo-Hyun Cho
- Gladstone Institute of Neurological Disease, University of California, San Francisco, California 94158, USA
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156
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Caviness JN, Lue LF, Beach TG, Hentz JG, Adler CH, Sue L, Sadeghi R, Driver-Dunckley E, Evidente VG, Sabbagh MN, Shill HA, Walker DG. Parkinson's disease, cortical dysfunction, and alpha-synuclein. Mov Disord 2011; 26:1436-42. [PMID: 21542019 DOI: 10.1002/mds.23697] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 01/30/2011] [Accepted: 02/07/2011] [Indexed: 11/08/2022] Open
Abstract
The ability to understand how Parkinson's disease neurodegeneration leads to cortical dysfunction will be critical for developing therapeutic advances in Parkinson's disease dementia. The overall purpose of this project was to study the small-amplitude cortical myoclonus in Parkinson's disease as an in vivo model of focal cortical dysfunction secondary to Parkinson's disease neurodegeneration. The objectives were to test the hypothesis that cortical myoclonus in Parkinson's disease is linked to abnormal levels of α-synuclein in the primary motor cortex and to define its relationship to various biochemical, clinical, and pathological measures. The primary motor cortex was evaluated for 11 Parkinson's disease subjects with and 8 without electrophysiologically confirmed cortical myoclonus (the Parkinson's disease + myoclonus group and the Parkinson's disease group, respectively) who had premortem movement and cognitive testing. Similarly assessed 9 controls were used for comparison. Measurements for α-synuclein, Aβ-42 peptide, and other biochemical measures were made in the primary motor cortex. A 36% increase in α-synuclein was found in the motor cortex of Parkinson's disease + myoclonus cases when compared with Parkinson's disease without myoclonus. This occurred without significant differences in insoluble α-synuclein, phosphorylated to total α-synuclein ratio, or Aβ-42 peptide levels. Higher total motor cortex α-synuclein levels significantly correlated with the presence of cortical myoclonus but did not correlate with multiple clinical or pathological findings. These results suggest an association between elevated α-synuclein and the dysfunctional physiology arising from the motor cortex in Parkinson's disease + myoclonus cases. Alzheimer's disease pathology was not associated with cortical myoclonus in Parkinson's disease. Cortical myoclonus arising from the motor cortex is a model to study cortical dysfunction in Parkinson's disease.
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Affiliation(s)
- John N Caviness
- Department of Neurology, Mayo Clinic, Scottsdale, Arizona, USA.
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157
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Kim C, Srivastava S, Rice M, Godenschwege TA, Bentley B, Ravi S, Shao S, Woodard CT, Schwartz LM. Expression of human amyloid precursor protein in the skeletal muscles of Drosophila results in age- and activity-dependent muscle weakness. BMC PHYSIOLOGY 2011; 11:7. [PMID: 21518451 PMCID: PMC3112101 DOI: 10.1186/1472-6793-11-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 04/25/2011] [Indexed: 12/16/2022]
Abstract
BACKGROUND One of the hallmarks of Alzheimer's disease, and several other degenerative disorders such as Inclusion Body Myositis, is the abnormal accumulation of amyloid precursor protein (APP) and its proteolytic amyloid peptides. To better understand the pathological consequences of inappropriate APP expression on developing tissues, we generated transgenic flies that express wild-type human APP in the skeletal muscles, and then performed anatomical, electrophysiological, and behavioral analysis of the adults. RESULTS We observed that neither muscle development nor animal longevity was compromised in these transgenic animals. However, human APP expressing adults developed age-dependent defects in both climbing and flying. We could advance or retard the onset of symptoms by rearing animals in vials with different surface properties, suggesting that human APP expression-mediated behavioral defects are influenced by muscle activity. Muscles from transgenic animals did not display protein aggregates or structural abnormalities at the light or transmission electron microscopic levels. In agreement with genetic studies performed with developing mammalian myoblasts, we observed that co-expression of the ubiquitin E3 ligase Parkin could ameliorate human APP-induced defects. CONCLUSIONS These data suggest that: 1) ectopic expression of human APP in fruit flies leads to age- and activity-dependent behavioral defects without overt changes to muscle development or structure; 2) environmental influences can greatly alter the phenotypic consequences of human APP toxicity; and 3) genetic modifiers of APP-induced pathology can be identified and analyzed in this model.
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Affiliation(s)
- Chul Kim
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, MA 01003, USA
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158
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Zong Y, Wang H, Dong W, Quan X, Zhu H, Xu Y, Huang L, Ma C, Qin C. miR-29c regulates BACE1 protein expression. Brain Res 2011; 1395:108-15. [PMID: 21565331 DOI: 10.1016/j.brainres.2011.04.035] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 04/12/2011] [Accepted: 04/19/2011] [Indexed: 01/07/2023]
Abstract
Recently, BACE1 expression was shown to be regulated by microRNAs, small endogenous RNA molecules that regulate protein expression through sequence-specific interaction with messenger RNA. Here, we showed that microRNA-29c (miR-29c), a miRNA that is enriched in the brain and highly expressed in the APPswe/PSΔE9 mouse lowers BACE1 protein in vitro and in transgenic miR-29c mice. In silico analysis identified two putative target sites in the BACE1 mRNA for the miR-29c family. We chose SH-SY5Y, HEK-293T cell lines and miR-29c transgenic mice for these studies to validate our hypothesis. Significantly, over-expression of miR-29c in SH-SY5Y, HEK-293T cell lines and miR-29c transgenic mice downregulated BACE1 protein levels. Our findings suggest that miR-29c may be an endogenous regulator of BACE1 protein expression.
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Affiliation(s)
- Yuanyuan Zong
- Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), No. 5, Panjiayuan, Nanli, Chaoyang District, Beijing 10021, PR China
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159
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Alzheimer's disease drug candidates stabilize A-β protein native structure by interacting with the hydrophobic core. Biophys J 2011; 100:1076-82. [PMID: 21320453 DOI: 10.1016/j.bpj.2010.12.3741] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 12/15/2010] [Accepted: 12/22/2010] [Indexed: 02/07/2023] Open
Abstract
Deposition of amyloid fibrils, consisting primarily of Aβ(40) and Aβ(42) peptides, in the extracellular space in the brain is a major characteristic of Alzheimer's disease (AD). We recently developed new (to our knowledge) drug candidates for AD that inhibit the fibril formation of Aβ peptides and eliminate their neurotoxicity. We performed all-atom molecular-dynamics simulations on the Aβ(42) monomer at its α-helical conformation and a pentamer fibril fragment of Aβ(42) peptide with or without LRL and fluorene series compounds to investigate the mechanism of inhibition. The results show that the active drug candidates, LRL22 (EC(50) = 0.734 μM) and K162 (EC(50) = 0.080 μM), stabilize hydrophobic core I of Aβ(42) peptide (residues 17-21) to its α-helical conformation by interacting specifically in this region. The nonactive drug candidates, LRL27 (EC(50) > 10 μM) and K182 (EC(50) > 5 μM), have little to no similar effect. This explains the different behavior of the drug candidates in experiments. Of more importance, this phenomenon indicates that hydrophobic core I of the Aβ(42) peptide plays a major mechanistic role in the formation of amyloid fibrils, and paves the way for the development of new drugs against AD.
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160
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Sepulveda-Falla D, Matschke J, Bernreuther C, Hagel C, Puig B, Villegas A, Garcia G, Zea J, Gomez-Mancilla B, Ferrer I, Lopera F, Glatzel M. Deposition of hyperphosphorylated tau in cerebellum of PS1 E280A Alzheimer's disease. Brain Pathol 2011; 21:452-63. [PMID: 21159009 DOI: 10.1111/j.1750-3639.2010.00469.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Early-onset familial Alzheimer's disease (AD) caused by presenilin-1 mutation E280A (PS1-E280A) presents wide clinical and neuropathological variabilities. We characterized clinically and neuropathologically PS1-E280A focusing in cerebellar involvement and compared it with early-onset sporadic Alzheimer's disease (EOSAD). Twelve E280A brains and 12 matched EOSAD brains were analyzed for beta-amyloid and hyperphosphorylated tau (pTau) morphology, beta-amyloid subspecies 1-40, 1-42 levels, pTau levels, and expression of stress kinases in frontal cortex and cerebellum. The data were correlated to clinical and genetic findings. We observed higher beta-amyloid load, beta-amyloid 1-42 and pTau concentrations in frontal cortex of PS1-E280A compared with EOSAD. High beta-amyloid load was found in the cerebellum of PS1-E280A and EOSAD patients. In PS1-E280A, beta-amyloid localized to the molecular and Purkinje cell layers, whereas EOSAD showed them in Purkinje and granular cell layers. Surprisingly, 11 out of 12 PS1-E280A patients showed deposition of pTau in the cerebellum. Also, seven out of 12 PS1-E280A patients presented cerebellar ataxia. We conclude that deposition of beta-amyloid in the cerebellum is prominent in early-onset AD irrespective of genetic or sporadic origin. The presence of pTau in cerebellum in PS1-E280A underscores the relevance of cerebellar involvement in AD and might be correlated to clinical phenotype.
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Affiliation(s)
- Diego Sepulveda-Falla
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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161
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Cissé M, Halabisky B, Harris J, Devidze N, Dubal DB, Sun B, Orr A, Lotz G, Kim DH, Hamto P, Ho K, Yu GQ, Mucke L. Reversing EphB2 depletion rescues cognitive functions in Alzheimer model. Nature 2011; 469:47-52. [PMID: 21113149 PMCID: PMC3030448 DOI: 10.1038/nature09635] [Citation(s) in RCA: 321] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Accepted: 11/08/2010] [Indexed: 12/11/2022]
Abstract
Amyloid-β oligomers may cause cognitive deficits in Alzheimer's disease by impairing neuronal NMDA-type glutamate receptors, whose function is regulated by the receptor tyrosine kinase EphB2. Here we show that amyloid-β oligomers bind to the fibronectin repeats domain of EphB2 and trigger EphB2 degradation in the proteasome. To determine the pathogenic importance of EphB2 depletions in Alzheimer's disease and related models, we used lentiviral constructs to reduce or increase neuronal expression of EphB2 in memory centres of the mouse brain. In nontransgenic mice, knockdown of EphB2 mediated by short hairpin RNA reduced NMDA receptor currents and impaired long-term potentiation in the dentate gyrus, which are important for memory formation. Increasing EphB2 expression in the dentate gyrus of human amyloid precursor protein transgenic mice reversed deficits in NMDA receptor-dependent long-term potentiation and memory impairments. Thus, depletion of EphB2 is critical in amyloid-β-induced neuronal dysfunction. Increasing EphB2 levels or function could be beneficial in Alzheimer's disease.
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Affiliation(s)
- Moustapha Cissé
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
- Department of Neurology, University of California, San Francisco, California 94158, USA
| | - Brian Halabisky
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
- Department of Neurology, University of California, San Francisco, California 94158, USA
| | - Julie Harris
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
- Department of Neurology, University of California, San Francisco, California 94158, USA
| | - Nino Devidze
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
| | - Dena B. Dubal
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
- Department of Neurology, University of California, San Francisco, California 94158, USA
| | - Binggui Sun
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
- Department of Neurology, University of California, San Francisco, California 94158, USA
| | - Anna Orr
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
- Department of Neurology, University of California, San Francisco, California 94158, USA
| | - Gregor Lotz
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
- Department of Neurology, University of California, San Francisco, California 94158, USA
| | - Daniel H. Kim
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
| | - Patricia Hamto
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
| | - Kaitlyn Ho
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
| | - Gui-Qiu Yu
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, San Francisco, California 94158, USA
- Department of Neurology, University of California, San Francisco, California 94158, USA
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162
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Kandimalla RJL, S P, BK B, Wani WY, Sharma DR, Grover V, Bhardwaj N, Jain K, Gill KD. Cerebrospinal fluid profile of amyloid β42 (Aβ42), hTau and ubiquitin in North Indian Alzheimer's disease patients. Neurosci Lett 2011; 487:134-8. [DOI: 10.1016/j.neulet.2010.06.075] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 06/03/2010] [Accepted: 06/28/2010] [Indexed: 10/19/2022]
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163
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Troy CM, Akpan N, Jean YY. Regulation of Caspases in the Nervous System. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 99:265-305. [DOI: 10.1016/b978-0-12-385504-6.00007-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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164
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Schaeffer EL, Figueiro M, Gattaz WF. Insights into Alzheimer disease pathogenesis from studies in transgenic animal models. Clinics (Sao Paulo) 2011; 66 Suppl 1:45-54. [PMID: 21779722 PMCID: PMC3118437 DOI: 10.1590/s1807-59322011001300006] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 03/16/2011] [Indexed: 01/16/2023] Open
Abstract
Alzheimer disease is the most common cause of dementia among the elderly, accounting for ~60-70% of all cases of dementia. The neuropathological hallmarks of Alzheimer disease are senile plaques (mainly containing p-amyloid peptide derived from amyloid precursor protein) and neurofibrillary tangles (containing hyperphosphorylated Tau protein), along with neuronal loss. At present there is no effective treatment for Alzheimer disease. Given the prevalence and poor prognosis of the disease, the development of animal models has been a research priority to understand pathogenic mechanisms and to test therapeutic strategies. Most cases of Alzheimer disease occur sporadically in people over 65 years old, and are not genetically inherited. Roughly 5% of patients with Alzheimer disease have familial Alzheimer disease--that is, related to a genetic predisposition, including mutations in the amyloid precursor protein, presenilin 1, and presenilin 2 genes. The discovery of genes for familial Alzheimer disease has allowed transgenic models to be generated through the overexpression of the amyloid precursor protein and/or presenilins harboring one or several mutations found in familial Alzheimer disease. Although none of these models fully replicates the human disease, they have provided valuable insights into disease mechanisms as well as opportunities to test therapeutic approaches. This review describes the main transgenic mouse models of Alzheimer disease which have been adopted in Alzheimer disease research, and discusses the insights into Alzheimer disease pathogenesis from studies in such models. In summary, the Alzheimer disease mouse models have been the key to understanding the roles of soluble b-amyloid oligomers in disease pathogenesis, as well as of the relationship between p-amyloid and Tau pathologies.
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Affiliation(s)
- Evelin L Schaeffer
- Laboratory of Neuroscience, Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, Brazil.
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Basi GS, Hemphill S, Brigham EF, Liao A, Aubele DL, Baker J, Barbour R, Bova M, Chen XH, Dappen MS, Eichenbaum T, Goldbach E, Hawkinson J, Lawler-Herbold R, Hu K, Hui T, Jagodzinski JJ, Keim PS, Kholodenko D, Latimer LH, Lee M, Marugg J, Mattson MN, McCauley S, Miller JL, Motter R, Mutter L, Neitzel ML, Ni H, Nguyen L, Quinn K, Ruslim L, Semko CM, Shapiro P, Smith J, Soriano F, Szoke B, Tanaka K, Tang P, Tucker JA, Ye XM, Yu M, Wu J, Xu YZ, Garofalo AW, Sauer JM, Konradi AW, Ness D, Shopp G, Pleiss MA, Freedman SB, Schenk D. Amyloid precursor protein selective gamma-secretase inhibitors for treatment of Alzheimer's disease. ALZHEIMERS RESEARCH & THERAPY 2010; 2:36. [PMID: 21190552 PMCID: PMC3031881 DOI: 10.1186/alzrt60] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 12/16/2010] [Accepted: 12/29/2010] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Inhibition of gamma-secretase presents a direct target for lowering Aβ production in the brain as a therapy for Alzheimer's disease (AD). However, gamma-secretase is known to process multiple substrates in addition to amyloid precursor protein (APP), most notably Notch, which has limited clinical development of inhibitors targeting this enzyme. It has been postulated that APP substrate selective inhibitors of gamma-secretase would be preferable to non-selective inhibitors from a safety perspective for AD therapy. METHODS In vitro assays monitoring inhibitor potencies at APP γ-site cleavage (equivalent to Aβ40), and Notch ε-site cleavage, in conjunction with a single cell assay to simultaneously monitor selectivity for inhibition of Aβ production vs. Notch signaling were developed to discover APP selective gamma-secretase inhibitors. In vivo efficacy for acute reduction of brain Aβ was determined in the PDAPP transgene model of AD, as well as in wild-type FVB strain mice. In vivo selectivity was determined following seven days x twice per day (b.i.d.) treatment with 15 mg/kg/dose to 1,000 mg/kg/dose ELN475516, and monitoring brain Aβ reduction vs. Notch signaling endpoints in periphery. RESULTS The APP selective gamma-secretase inhibitors ELN318463 and ELN475516 reported here behave as classic gamma-secretase inhibitors, demonstrate 75- to 120-fold selectivity for inhibiting Aβ production compared with Notch signaling in cells, and displace an active site directed inhibitor at very high concentrations only in the presence of substrate. ELN318463 demonstrated discordant efficacy for reduction of brain Aβ in the PDAPP compared with wild-type FVB, not observed with ELN475516. Improved in vivo safety of ELN475516 was demonstrated in the 7d repeat dose study in wild-type mice, where a 33% reduction of brain Aβ was observed in mice terminated three hours post last dose at the lowest dose of inhibitor tested. No overt in-life or post-mortem indications of systemic toxicity, nor RNA and histological end-points indicative of toxicity attributable to inhibition of Notch signaling were observed at any dose tested. CONCLUSIONS The discordant in vivo activity of ELN318463 suggests that the potency of gamma-secretase inhibitors in AD transgenic mice should be corroborated in wild-type mice. The discovery of ELN475516 demonstrates that it is possible to develop APP selective gamma-secretase inhibitors with potential for treatment for AD.
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Affiliation(s)
- Guriqbal S Basi
- Elan Pharmaceuticals, Inc, 180 Oyster Point Blvd, S, San Francisco, CA 94080, USA.
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Kalifa S, Polston EK, Allard JS, Manaye KF. Distribution patterns of cannabinoid CB1 receptors in the hippocampus of APPswe/PS1ΔE9 double transgenic mice. Brain Res 2010; 1376:94-100. [PMID: 21192920 DOI: 10.1016/j.brainres.2010.12.061] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 12/02/2010] [Accepted: 12/19/2010] [Indexed: 10/18/2022]
Abstract
Cannabinoids have neuroprotective effects that are exerted primarily through cannabinoid CB1 receptors in the brain. This study characterized CB1 receptor distribution in the double transgenic (dtg) APP(swe)/PS1(ΔE9) mouse model for Alzheimer's disease. Immunohistochemical labeling of CB1 protein in non-transgenic mice revealed that CB1 was highly expressed in the hippocampus, with the greatest density of CB1 protein observed in the combined hippocampal subregions CA2 and CA3 (CA2/3). CB1 immunoreactivity in the CA1 and CA2/3 hippocampal regions was significantly decreased in the dtg APP(swe)/PS1(ΔE9) mice compared to non-transgenic littermates. Reduced CB1 expression in dtg APP(swe)/PS1(ΔE9) mice was associated with astroglial proliferation and elevated expression of the cytokines inducible nitric oxide synthase and tumor necrosis factor alpha. This finding suggests an anti-inflammatory effect of cannabinoids that is mediated by CB1 receptor, particularly in the CA2/3 region of the hippocampus. Furthermore, the study suggests a decreased CB1 receptor expression may result in diminished anti-inflammatory processes, exacerbating the neuropathology associated with Alzheimer's disease.
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Affiliation(s)
- Sara Kalifa
- Department of Physiology and Biophysics, Howard University, Washington, DC 20059, USA
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167
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Harris JA, Devidze N, Verret L, Ho K, Halabisky B, Thwin MT, Kim D, Hamto P, Lo I, Yu GQ, Palop JJ, Masliah E, Mucke L. Transsynaptic progression of amyloid-β-induced neuronal dysfunction within the entorhinal-hippocampal network. Neuron 2010; 68:428-41. [PMID: 21040845 PMCID: PMC3050043 DOI: 10.1016/j.neuron.2010.10.020] [Citation(s) in RCA: 245] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2010] [Indexed: 12/14/2022]
Abstract
The entorhinal cortex (EC) is one of the earliest affected, most vulnerable brain regions in Alzheimer's disease (AD), which is associated with amyloid-β (Aβ) accumulation in many brain areas. Selective overexpression of mutant amyloid precursor protein (APP) predominantly in layer II/III neurons of the EC caused cognitive and behavioral abnormalities characteristic of mouse models with widespread neuronal APP overexpression, including hyperactivity, disinhibition, and spatial learning and memory deficits. APP/Aβ overexpression in the EC elicited abnormalities in synaptic functions and activity-related molecules in the dentate gyrus and CA1 and epileptiform activity in parietal cortex. Soluble Aβ was observed in the dentate gyrus, and Aβ deposits in the hippocampus were localized to perforant pathway terminal fields. Thus, APP/Aβ expression in EC neurons causes transsynaptic deficits that could initiate the cortical-hippocampal network dysfunction in mouse models and human patients with AD.
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Affiliation(s)
- Julie A. Harris
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Nino Devidze
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Laure Verret
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Kaitlyn Ho
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Brian Halabisky
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Myo T. Thwin
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Daniel Kim
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Patricia Hamto
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Iris Lo
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Gui-Qiu Yu
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Jorge J. Palop
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Eliezer Masliah
- Departments of Neurosciences, University of California, San Diego, San Diego, CA 92093, USA
- Department of Pathology, University of California, San Diego, San Diego, CA 92093, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
- Department of Neurology, University of California, San Francisco, CA 94158, USA
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Panza F, Frisardi V, Imbimbo BP, D’Onofrio G, Pietrarossa G, Seripa D, Pilotto A, Solfrizzi V. Bapineuzumab: anti-β-amyloid monoclonal antibodies for the treatment of Alzheimer’s disease. Immunotherapy 2010; 2:767-82. [DOI: 10.2217/imt.10.80] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
In the last decade, new therapeutic approaches targeting β-amyloid (Aβ) have been discovered and developed with the hope of modifying the natural history of Alzheimer’s disease (AD). The most revolutionary of these approaches consists in the removal of brain Aβ via anti-Aβ antibodies. After an active vaccine (AN1792) was discontinued in 2002 due to occurrence of meningoencephalitis in approximately 6% of patients, several other second-generation active Aβ vaccines and passive Aβ immunotherapies have been developed and are under clinical investigation with the aim of accelerating Aβ clearance from the brain of AD patients. The most advanced of these immunological approaches is bapineuzumab, which is composed of humanized anti-Aβ monoclonal antibodies that has been tested in two Phase II trials. Bapineuzumab has been shown to reduce Aβ burden in the brain of AD patients. However, its preliminary cognitive efficacy appears uncertain, particularly in ApoE ε4 carriers, and vasogenic edema may limit its clinical use. The results of four ongoing large Phase III trials on bapineuzumab will provide answers regarding whether passive anti-Aβ immunization is able to alter the course of this devastating disease.
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Affiliation(s)
| | - Vincenza Frisardi
- Department of Geriatrics, Center for Aging Brain, Memory Unit, University of Bari, Bari, Italy
| | - Bruno P Imbimbo
- Research & Development Department, Chiesi Farmaceutici, Parma, Italy
| | - Grazia D’Onofrio
- Geriatric Unit & Gerontology-Geriatric Research Laboratory, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | | | - Davide Seripa
- Geriatric Unit & Gerontology-Geriatric Research Laboratory, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Alberto Pilotto
- Geriatric Unit & Gerontology-Geriatric Research Laboratory, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Vincenzo Solfrizzi
- Department of Geriatrics, Center for Aging Brain, Memory Unit, University of Bari, Bari, Italy
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169
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Probst GD, Bowers S, Sealy JM, Stupi B, Dressen D, Jagodzinska BM, Aquino J, Gailunas A, Truong AP, Tso L, Xu YZ, Hom RK, John V, Tung JS, Pleiss MA, Tucker JA, Konradi AW, Sham HL, Jagodzinski J, Toth G, Brecht E, Yao N, Pan H, Lin M, Artis DR, Ruslim L, Bova MP, Sinha S, Yednock TA, Gauby S, Zmolek W, Quinn KP, Sauer JM. Design and synthesis of hydroxyethylamine (HEA) BACE-1 inhibitors: Structure–activity relationship of the aryl region. Bioorg Med Chem Lett 2010; 20:6034-9. [DOI: 10.1016/j.bmcl.2010.08.070] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 08/11/2010] [Accepted: 08/12/2010] [Indexed: 11/29/2022]
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Abstract
IMPORTANCE OF THE FIELD Alzheimer's disease is the leading cause of dementia in the elderly, and there is no disease-modifying therapy yet available. Immunotherapy directed against the beta-amyloid peptide may be capable of slowing the rate of disease progression. Bapineuzumab, an anti-beta-amyloid monoclonal antibody, will be the first such agent to emerge from Phase III clinical trials. AREAS COVERED IN THIS REVIEW The primary literature on bapineuzumab from 2009 and 2010 is reviewed in its entirety, along with the literature on AN1792, a first-generation anti-beta-amyloid vaccine, from 2003 to 2009. Other Alzheimer's disease immunotherapeutics currently in development, according to www.clinicaltrials.gov , are also discussed. WHAT THE READER WILL GAIN In addition to a critical appraisal of the Phase II trial results for bapineuzumab, this review considers the broader field of immunotherapy for Alzheimer's disease as a whole, including the challenges ahead. TAKE HOME MESSAGE Bapineuzumab appears capable of reducing the cerebral beta-amyloid peptide burden in patients with Alzheimer's disease. However, particularly in APOE 4 carriers, its ability to slow disease progression remains uncertain, and vasogenic edema - a dose-limiting and potentially severe adverse reaction - may limit its clinical applicability.
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Affiliation(s)
- Geoffrey A Kerchner
- Stanford University School of Medicine, Stanford Center for Memory Disorders, 300 Pasteur Drive, Room A343, Stanford, CA 94305-5235, USA
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171
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Hurtado DE, Molina-Porcel L, Iba M, Aboagye AK, Paul SM, Trojanowski JQ, Lee VMY. A{beta} accelerates the spatiotemporal progression of tau pathology and augments tau amyloidosis in an Alzheimer mouse model. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 177:1977-88. [PMID: 20802182 DOI: 10.2353/ajpath.2010.100346] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Senile plaques formed by β-amyloid peptides (Aβ) and neurofibrillary tangles (NFTs) formed by hyperphosphorylated tau, a microtubule-associated protein, are the hallmark lesions of Alzheimer's disease (AD) in addition to loss of neurons. While several transgenic (Tg) mouse models have recapitulated aspects of AD-like Aβ and tau pathologies, a spatiotemporal mapping paradigm for progressive NFT accumulation is urgently needed to stage disease progression in AD mouse models. Braak and co-workers developed an effective and widely used NFT staging paradigm for human AD brains. The creation of a Braak-like spatiotemporal staging scheme for tau pathology in mouse models would facilitate mechanistic studies of AD-like tau pathology. Such a scheme would also enhance the reproducibility of preclinical AD therapeutic studies. Thus, we developed a novel murine model of Aβ and tau pathologies and devised a spatiotemporal scheme to stage the emergence and accumulation of NFTs with advancing age. Notably, the development of NFTs followed a spatiotemporal Braak-like pattern similar to that observed in authentic AD. More significantly, the presence of Aβ accelerated NFT formation and enhanced tau amyloidosis; however, tau pathology did not have the same effect on Aβ pathology. This novel NFT staging scheme provides new insights into the mechanisms of tau pathobiology, and we speculate that this scheme will prove useful for other basic and translational studies of AD mouse models.
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Affiliation(s)
- David E Hurtado
- Department of Pathology, Laboratory Medicine, Center for Neurodegenerative Disease Research, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-4283, USA
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172
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Wang L, Sato H, Zhao S, Tooyama I. Deposition of lactoferrin in fibrillar-type senile plaques in the brains of transgenic mouse models of Alzheimer's disease. Neurosci Lett 2010; 481:164-7. [PMID: 20599473 DOI: 10.1016/j.neulet.2010.06.079] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Revised: 06/11/2010] [Accepted: 06/25/2010] [Indexed: 11/28/2022]
Abstract
We and others have previously reported that lactoferrin (LF), which acts as both an iron-binding protein and an inflammatory modulator, is strongly up-regulated in the brains of patients with Alzheimer's disease (AD). We have also studied the expression and localization of LF mRNA in the brain cortices of patients with AD. In this study, we investigated immunohistochemically the localization of LF in the brains of APP-transgenic mice, representing a model of AD. No LF immunoreactivity was detected in the brains of the wild-type mice. In the transgenic AD mice, LF deposition was detected in the brains. Double-immunofluorescence staining with antibodies directed against the amyloid-beta peptide (Abeta) and LF localized the LF depositions to amyloid deposits (senile plaques) and regions of amyloid angiopathy. Senile plaque formation precedes LF deposition in AD. In the transgenic mice aged <18 months, most of senile plaques were negative for LF. LF deposits appeared weakly at about 18 months of age in these mice. Both the intensity and number of LF-positive depositions in the transgenic mice increased with age. Double-staining for LF and thioflavin-S revealed that LF accumulated in thioflavin-S-positive, fibrillar-type senile plaques. The up-regulation of LF in the brains of both AD patients and the transgenic mouse model of AD provides evidence of an important role for LF in AD-affected brain tissues.
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Affiliation(s)
- Ligang Wang
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu 520-2192, Japan
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173
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L-3-n-butylphthalide improves cognitive impairment and reduces amyloid-beta in a transgenic model of Alzheimer's disease. J Neurosci 2010; 30:8180-9. [PMID: 20554868 DOI: 10.1523/jneurosci.0340-10.2010] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Alzheimer's disease (AD) is an age-related, progressive neurodegenerative disorder that occurs gradually and results in memory, behavior, and personality changes. L-3-n-butylphthalide (L-NBP), an extract from seeds of Apium graveolens Linn (Chinese celery), has been demonstrated to have neuroprotective effects on ischemic, vascular dementia, and amyloid-beta (Abeta)-infused animal models. In the current study, we examined the effects of L-NBP on learning and memory in a triple-transgenic AD mouse model (3xTg-AD) that develops both plaques and tangles with aging, as well as cognitive deficits. Ten-month-old 3xTg-AD mice were given 15 mg/kg L-NBP by oral gavage for 18 weeks. L-NBP treatment significantly improved learning deficits, as well as long-term spatial memory, compared with vehicle control treatment. L-NBP treatment significantly reduced total cerebral Abeta plaque deposition and lowered Abeta levels in brain homogenates but had no effect on fibrillar Abeta plaques, suggesting preferential removal of diffuse Abeta deposits. Furthermore, we found that L-NBP markedly enhanced soluble amyloid precursor protein secretion (alphaAPPs), alpha-secretase, and PKCalpha expression but had no effect on steady-state full-length APP. Thus, L-NBP may direct APP processing toward a non-amyloidogenic pathway and preclude Abeta formation in the 3xTg-AD mice. The effect of l-NBP on regulating APP processing was further confirmed in neuroblastoma SK-N-SH cells overexpressing wild-type human APP(695) (SK-N-SH APPwt). L-NBP treatment in 3xTg-AD mice also reduced glial activation and oxidative stress compared with control treatment. L-NBP shows promising preclinical potential as a multitarget drug for the prevention and/or treatment of Alzheimer's disease.
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174
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Boche D, Donald J, Love S, Harris S, Neal JW, Holmes C, Nicoll JAR. Reduction of aggregated Tau in neuronal processes but not in the cell bodies after Abeta42 immunisation in Alzheimer's disease. Acta Neuropathol 2010; 120:13-20. [PMID: 20532897 DOI: 10.1007/s00401-010-0705-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 05/24/2010] [Accepted: 05/25/2010] [Indexed: 10/19/2022]
Abstract
Alzheimer's disease (AD) pathology is characterised by aggregation in the brain of amyloid-beta (Abeta) peptide and hyperphosphorylated tau (phospho-tau), although how these proteins interact in disease pathogenesis is unclear. Abeta immunisation results in removal of Abeta from the brain but cognitive decline continues to progress, possibly due to persistent phospho-tau. We quantified phospho-tau and Abeta42 in the brains of 10 AD patients (iAD) who were actively immunised with Abeta42 (AN1792, Elan Pharmaceuticals) compared with 28 unimmunised AD cases (cAD). The phospho-tau load was lower in the iAD than the cAD group in the cerebral cortex (cAD 1.08% vs. iAD 0.72%, P = 0.048), CA1 hippocampus (cAD 2.26% vs. iAD 1.05%; P = 0.001), subiculum (cAD 1.60% vs. iAD 0.31%; P = 0.001) and entorhinal cortex (cAD 1.10% vs. iAD 0.18%; P < 0.001). Assessment of the localisation within neurons of phospho-tau indicated that the Abeta immunotherapy-associated reduction was confined to neuronal processes, i.e. neuropil threads and dystrophic neurites. However, the phospho-tau accumulation in the neuronal cell bodies, contributing to neurofibrillary tangles, appeared not to be affected. In showing that Abeta immunisation can influence phospho-tau pathology, we confirm the position of Abeta as a target for modifying tau accumulation in AD and demonstrate a link between these proteins. However, the continuing progression of cognitive decline in AD patients after Abeta immunisation may be explained by its lack of apparent effect on tangles.
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175
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Sun B, Halabisky B, Zhou Y, Palop JJ, Yu G, Mucke L, Gan L. Imbalance between GABAergic and Glutamatergic Transmission Impairs Adult Neurogenesis in an Animal Model of Alzheimer's Disease. Cell Stem Cell 2010; 5:624-33. [PMID: 19951690 DOI: 10.1016/j.stem.2009.10.003] [Citation(s) in RCA: 160] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 08/24/2009] [Accepted: 10/07/2009] [Indexed: 12/11/2022]
Abstract
Adult neurogenesis regulates plasticity and function in the hippocampus, which is critical for memory and vulnerable to Alzheimer's disease (AD). Promoting neurogenesis may improve hippocampal function in AD brains. However, how amyloid beta (Abeta), the key AD pathogen, affects the development and function of adult-born neurons remains unknown. Adult-born granule cells (GCs) in human amyloid precursor protein (hAPP) transgenic mice, an AD model, showed greater dendritic length, spine density, and functional responses than did controls early in development, but were impaired morphologically and functionally during later maturation. Early inhibition of GABA(A) receptors to suppress GABAergic signaling or late inhibition of calcineurin to enhance glutamatergic signaling normalized the development of adult-born GCs in hAPP mice with high Abeta levels. Abeta-induced increases in GABAergic neurotransmission or an imbalance between GABAergic and glutamatergic neurotransmission may contribute to impaired neurogenesis in AD.
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Affiliation(s)
- Binggui Sun
- Gladstone Institute of Neurological Disease, University of California, San Francisco, 94158, USA
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176
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Dickstein DL, Walsh J, Brautigam H, Stockton SD, Gandy S, Hof PR. Role of vascular risk factors and vascular dysfunction in Alzheimer's disease. ACTA ACUST UNITED AC 2010; 77:82-102. [PMID: 20101718 DOI: 10.1002/msj.20155] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Recent findings indicate that vascular risk factors and neurovascular dysfunction play integral roles in the pathogenesis of Alzheimer's disease. In addition to aging, the most common risk factors for Alzheimer's disease are apolipoprotein e4 allele, hypertension, hypotension, diabetes, and hypercholesterolemia. All of these can be characterized by vascular pathology attributed to conditions such as cerebral amyloid angiopathy and subsequent blood-brain barrier dysfunction. Many epidemiological, clinical, and pharmacotherapeutic studies have assessed the associations between such risk factors and Alzheimer's disease and have found positive associations between hypertension, hypotension, and diabetes mellitus. However, there are still many conflicting results from these population-based studies, and they should be interpreted carefully. Recognition of these factors and the mechanisms by which they contribute to Alzheimer's disease will be beneficial in the current treatment regimens for Alzheimer's disease and in the development of future therapies. Here we discuss vascular factors with respect to Alzheimer's disease and dementia and review the factors that give rise to vascular dysfunction and contribute to Alzheimer's disease.
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Affiliation(s)
- Dara L Dickstein
- Department of Neuroscience and Kastor Neurobiology of Aging Laboratories, Mount Sinai School of Medicine, New York, NY, USA.
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Mc Donald JM, Savva GM, Brayne C, Welzel AT, Forster G, Shankar GM, Selkoe DJ, Ince PG, Walsh DM. The presence of sodium dodecyl sulphate-stable Abeta dimers is strongly associated with Alzheimer-type dementia. ACTA ACUST UNITED AC 2010; 133:1328-41. [PMID: 20403962 DOI: 10.1093/brain/awq065] [Citation(s) in RCA: 211] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The molecular pathways leading to Alzheimer-type dementia are not well understood, but the amyloid beta-protein is believed to be centrally involved. The quantity of amyloid beta-protein containing plaques does not correlate well with clinical status, suggesting that if amyloid beta-protein is pathogenic it involves soluble non-plaque material. Using 43 brains from the Newcastle cohort of the population-representative Medical Research Council Cognitive Function and Ageing Study, we examined the relationship between biochemically distinct forms of amyloid beta-protein and the presence of Alzheimer-type dementia. Cortical samples were serially extracted with Tris-buffered saline, Tris-buffered saline containing 1% TX-100 and with 88% formic acid and extracts analysed for amyloid beta-protein by immunoprecipitation/western blotting. The cohort was divisible into those with dementia at death with (n = 14) or without (n = 10) significant Alzheimer-type pathology, and those who were not demented (n = 19). Amyloid beta-protein monomer in extracts produced using Tris-buffered saline and Tris-buffered saline containing 1% TX-100 were strongly associated with Alzheimer type dementia (P < 0.001) and sodium dodecyl sulphate-stable amyloid beta-protein dimer was detected specifically and sensitively in Tris-buffered saline, Tris-buffered saline containing 1% TX-100 and formic acid extracts of Alzheimer brain. Amyloid beta-protein monomer in the formic acid fraction closely correlated with diffuse and neuritic plaque burden, but was not specific for dementia. These findings support the hypothesis that soluble amyloid beta-protein is a major correlate of dementia associated with Alzheimer-type pathology and is likely to be intimately involved in the pathogenesis of cognitive failure.
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Affiliation(s)
- Jessica M Mc Donald
- Laboratory for Neurodegenerative Research, School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin 4, Republic of Ireland
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178
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Arslanova D, Yang T, Xu X, Wong ST, Augelli-Szafran CE, Xia W. Phenotypic analysis of images of zebrafish treated with Alzheimer's gamma-secretase inhibitors. BMC Biotechnol 2010; 10:24. [PMID: 20307292 PMCID: PMC2851663 DOI: 10.1186/1472-6750-10-24] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 03/22/2010] [Indexed: 11/16/2022] Open
Abstract
Background Several γ-secretase inhibitors (GSI) are in clinical trials for the treatment of Alzheimer's disease (AD). This enzyme mediates the proteolytic cleavage of amyloid precursor protein (APP) to generate amyloid β protein, Aβ, the pathogenic protein in AD. The γ-secretase also cleaves Notch to generate Notch Intracellular domain (NICD), the signaling molecule that is implicated in tumorigenesis. Results We have developed a method to examine live zebrafish that were each treated with γ-secretase inhibitors (GSI), DAPT {N- [N-(3,5-Difluorophenacetyl-L-alanyl)]-S-phenylglycine t-Butyl Ester}, Gleevec, or fragments of Gleevec. These compounds were first tested in a cell-based assay and the effective concentrations of these compounds that blocked Aβ generation were quantitated. The mortality of zebrafish, as a result of exposure to different doses of compound, was assessed, and any apoptotic processes were examined by TUNEL staining. We then used conventional and automatic microscopes to acquire images of zebrafish and applied algorithms to automate image composition and processing. Zebrafish were treated in 96- or 384-well plates, and the phenotypes were analyzed at 2, 3 and 5 days post fertilization (dpf). We identified that AD95, a fragment of Gleevec, effectively blocks Aβ production and causes specific phenotypes that were different from those treated with DAPT. Finally, we validated the specificity of two Notch phenotypes (pigmentation and the curvature of tail/trunk) induced by DAPT in a dose-dependent manner. These phenotypes were examined in embryos treated with GSIs or AD95 at increasing concentrations. The expression levels of Notch target gene her6 were also measured by in situ hybridization and the co-relationship between the levels of Notch inhibition by DAPT and AD95 and the severity of phenotypes were determined. Conclusion The results reported here of the effects on zebrafish suggest that this newly developed method may be used to screen novel GSIs and other leads for a variety of therapeutic indications.
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Affiliation(s)
- Dilyara Arslanova
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Harvard University, Boston, MA, USA
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Amyloid beta induces the morphological neurodegenerative triad of spine loss, dendritic simplification, and neuritic dystrophies through calcineurin activation. J Neurosci 2010; 30:2636-49. [PMID: 20164348 DOI: 10.1523/jneurosci.4456-09.2010] [Citation(s) in RCA: 293] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Amyloid beta (Abeta)-containing plaques are surrounded by dystrophic neurites in the Alzheimer's disease (AD) brain, but whether and how plaques induce these neuritic abnormalities remain unknown. We tested the hypothesis that soluble oligomeric assemblies of Abeta, which surround plaques, induce calcium-mediated secondary cascades that lead to dystrophic changes in local neurites. We show that soluble Abeta oligomers lead to activation of the calcium-dependent phosphatase calcineurin (CaN) (PP2B), which in turn activates the transcriptional factor nuclear factor of activated T cells (NFAT). Activation of these signaling pathways, even in the absence of Abeta, is sufficient to produce a virtual phenocopy of Abeta-induced dystrophic neurites, dendritic simplification, and dendritic spine loss in both neurons in culture and in the adult mouse brain. Importantly, the morphological deficits in the vicinity of Abeta deposits in a mouse model of AD are ameliorated by CaN inhibition, supporting the hypothesis that CaN-NFAT are aberrantly activated by Abeta and that CaN-NFAT activation is responsible for disruption of neuronal structure near plaques. In accord with this, we also detect increased levels of an active form of CaN and NFATc4 in the nuclear fraction from the cortex of patients with AD. Thus, Abeta appears to mediate the neurodegeneration of AD, at least in part, by activation of CaN and subsequent NFAT-mediated downstream cascades.
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180
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España J, Giménez-Llort L, Valero J, Miñano A, Rábano A, Rodriguez-Alvarez J, LaFerla FM, Saura CA. Intraneuronal beta-amyloid accumulation in the amygdala enhances fear and anxiety in Alzheimer's disease transgenic mice. Biol Psychiatry 2010; 67:513-21. [PMID: 19664757 DOI: 10.1016/j.biopsych.2009.06.015] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Revised: 06/18/2009] [Accepted: 06/19/2009] [Indexed: 10/20/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is characterized by progressive memory decline and neuropsychiatric symptoms. Despite common emotional symptoms in AD such as anxiety and fear are associated with a more rapid cognitive decline, the pathological mechanisms involved in these behavioral changes remain largely elusive. In this study, we examined the pathological mechanisms of emotional behavior in well-established AD transgenic mice expressing human mutant beta-amyloid (Abeta) precursor protein (APP(Ind) and APP(Sw,Ind)) and tau (3xTg-AD). METHODS We evaluated unconditioned and conditioned fear-induced freezing behavior and spatial memory in APP(Ind), APP(Sw,Ind), and 3xTg-AD transgenic mice. The Abeta and tau pathologies and signaling pathways involved in emotional processing were studied by immunohistochemistry and immunoblotting analyses. RESULTS The APP(Ind)/APP(Sw,Ind) and 3xTg-AD transgenic mice displayed at early ages enhanced innate and conditioned fear symptoms and spatial memory deficits coinciding with enhanced accumulation of Abeta in gamma-aminobutyric acid (GABA)ergic and glutamatergic neurons, respectively, of the basolateral amygdala (BLA). Similarly, the number of neurons with intraneuronal Abeta40 and Abeta42 was significantly increased in the BLA of human AD brains. Fear responses might reflect an influence of anxiety, because the anxiolytic compounds valproate, diazepam, and buspirone reduced efficiently unconditioned and conditioned fear responses in APP transgenic mice. In addition, phosphorylation of extracellular signal-regulated kinase (ERK)1/2, which is critical for acquisition and consolidation of fear conditioning, was increased in the amygdala of APP transgenic mice after cued conditioning. CONCLUSIONS We propose a deleterious role of intraneuronal Abeta on amygdala-dependent emotional responses by affecting the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling pathway.
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Affiliation(s)
- Judit España
- Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Spain
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181
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Yang T, Arslanova D, Xu X, Li YM, Xia W. In vivo manifestation of Notch related phenotypes in zebrafish treated with Alzheimer's amyloid reducing gamma-secretase inhibitors. J Neurochem 2010; 113:1200-9. [PMID: 20345767 DOI: 10.1111/j.1471-4159.2010.06681.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Gamma-secretase is responsible for the final cleavage of amyloid precursor protein to generate the amyloid-beta protein, the major component of plaques in the brains of Alzheimer's disease patients. gamma-Secretase inhibitors (GSI) have been explored for therapeutic inhibition of amyloid beta protein generation, but mechanistic toxicity has been documented because of its blockage of gamma-secretase cleavage of several dozens of substrates including Notch. This becomes the primary obstacle for most inhibitors during the pre-clinical development and the main concern for several compounds in the clinical trials. To predict potential side effects related to Notch signaling, we examined global effect of GSIs in vertebrate animal zebrafish. We have used two potent GSIs (GSI A and GSI 18) with a sub-microM effective concentration for 50% amyloid beta protein inhibition (EC(50)). Zebrafish embryos were treated with GSI A, 18 or a well characterized GSI N-[N-(3,5-difluorophenacetyl-L-alanyl)]-S-phenylglycine t-butyl ester (DAPT), and transparent animals were examined for up to 7 days. GSI A had less abnormal phenotype in zebrafish, compared to GSI 18-treated embryos that displayed curved tails, a loss of pigmentation, and reduced swim bladder and heart rate. To understand mechanistic effect at the molecular level, we examined Notch signaling in these GSI-treated zebrafish. Notch phenotypes were observed in embryos treated with 50 and 10 microM GSI 18, but not with 10 microM GSI A. In accordance, in situ hybridization with a probe against Notch target gene her6 showed a weaker staining in embryos treated with 10 microM GSI 18 than those treated with 10 microM GSI A. In conclusion, phenotypic profile in whole animals offers important information on Notch related pathways and provides prediction of safe compounds during early development stages of therapeutic GSIs.
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Affiliation(s)
- Ting Yang
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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182
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Mori T, Koyama N, Arendash GW, Horikoshi-Sakuraba Y, Tan J, Town T. Overexpression of human S100B exacerbates cerebral amyloidosis and gliosis in the Tg2576 mouse model of Alzheimer's disease. Glia 2010; 58:300-14. [PMID: 19705461 DOI: 10.1002/glia.20924] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Alzheimer's disease (AD) is the most common progressive dementia and is pathologically characterized by brain deposition of amyloid-beta (Abeta) peptide as senile plaques. Inflammatory and immune response pathways are chronically activated in AD patient brains at low levels, and likely play a role in disease progression. Like microglia, activated astrocytes produce numerous acute-phase reactants and proinflammatory molecules in the AD brain. One such molecule, S100B, is highly expressed by reactive astrocytes in close vicinity of beta-amyloid deposits. We have previously shown that augmented and prolonged activation of astrocytes has a detrimental impact on neuronal survival. Furthermore, we have implicated astrocyte-derived S100B as a candidate molecule responsible for this deleterious effect. To evaluate a putative relationship between S100B and AD pathogenesis, we crossed transgenic mice overexpressing human S100B (TghuS100B mice) with the Tg2576 mouse model of AD, and examined AD-like pathology. Brain parenchymal and cerebral vascular beta-amyloid deposits and Abeta levels were increased in bigenic Tg2576-huS100B mice. These effects were associated with increased cleavage of the beta-C-terminal fragment of amyloid precursor protein (APP), elevation of the N-terminal APP cleavage product (soluble APPbeta), and activation of beta-site APP cleaving enzyme 1. In addition, double transgenic mice showed augmented reactive astrocytosis and microgliosis, high levels of S100 expression, and increased levels of proinflammatory cytokines as early as 7-9 months of age. These results provide evidence that (over)-expression of S100B acts to accelerate AD-like pathology, and suggest that inhibiting astrocytic activation by blocking S100B biosynthesis may be a promising therapeutic strategy to delay AD progression..
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Affiliation(s)
- Takashi Mori
- Department of Medical Science, Saitama Medical Center and University, Kawagoe, Saitama, Japan.
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183
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Philipson O, Lord A, Gumucio A, O'Callaghan P, Lannfelt L, Nilsson LNG. Animal models of amyloid-beta-related pathologies in Alzheimer's disease. FEBS J 2010; 277:1389-409. [PMID: 20136653 DOI: 10.1111/j.1742-4658.2010.07564.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In the early 1990s, breakthrough discoveries on the genetics of Alzheimer's disease led to the identification of missense mutations in the amyloid-beta precursor protein gene. Research findings quickly followed, giving insights into molecular pathogenesis and possibilities for the development of new types of animal models. The complete toolbox of transgenic techniques, including pronuclear oocyte injection and homologous recombination, has been applied in the Alzheimer's disease field, to produce overexpressors, knockouts, knockins and regulatable transgenics. Transgenic models have dramatically advanced our understanding of pathogenic mechanisms and allowed therapeutic approaches to be tested. Following a brief introduction to Alzheimer's disease, various nontransgenic and transgenic animal models are described in terms of their values and limitations with respect to pathogenic, therapeutic and functional understandings of the human disease.
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Affiliation(s)
- Ola Philipson
- Department of Public Health and Caring Sciences/Molecular Geriatrics, Uppsala University, Sweden
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184
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Fish oil enhances anti-amyloidogenic properties of green tea EGCG in Tg2576 mice. Neurosci Lett 2010; 471:134-8. [PMID: 20096749 DOI: 10.1016/j.neulet.2010.01.026] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 01/12/2010] [Accepted: 01/13/2010] [Indexed: 02/08/2023]
Abstract
Extracellular plaques of beta-amyloid (Abeta) peptides are implicated in Alzheimer's Disease (AD) pathogenesis. Abeta formation is precluded by alpha-secretase, which cleaves within the Abeta domain of APP generating soluble APP-alpha (sAPP-alpha). Thus, alpha-secretase upregulation may be a target AD therapy. We previously showed green tea derived EGCG increased sAPP-alpha in AD mouse models. However, the comparable effective dose of EGCG in humans may exceed clinical convenience and/or safety. Epidemiological studies suggested fish oil consumption is associated with reduced dementia risk. Here we investigated whether oral co-treatment with fish oil (8mg/kg/day) and EGCG (62.5mg/kg/day or 12.5mg/kg/day) would reduce AD-like pathology in Tg2576 mice. In vitro co-treatment of N2a cells with fish oil and EGCG enhanced sAPP-alpha production compared to either compound alone (P<0.001). Fish oil enhanced bioavailability of EGCG versus EGCG treatment alone (P<0.001). Fish oil and EGCG had a synergetic effect on inhibition of cerebral Abeta deposits (P<0.001) suggesting moderate supplementation with EGCG and fish oil having significant therapeutic potential for the treatment of AD.
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185
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Harris JA, Devidze N, Halabisky B, Lo I, Thwin MT, Yu GQ, Bredesen DE, Masliah E, Mucke L. Many neuronal and behavioral impairments in transgenic mouse models of Alzheimer's disease are independent of caspase cleavage of the amyloid precursor protein. J Neurosci 2010; 30:372-81. [PMID: 20053918 PMCID: PMC3064502 DOI: 10.1523/jneurosci.5341-09.2010] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 11/02/2009] [Indexed: 11/21/2022] Open
Abstract
Previous studies suggested that cleavage of the amyloid precursor protein (APP) at aspartate residue 664 by caspases may play a key role in the pathogenesis of Alzheimer's disease. Mutation of this site (D664A) prevents caspase cleavage and the generation of the C-terminal APP fragments C31 and Jcasp, which have been proposed to mediate amyloid-beta (Abeta) neurotoxicity. Here we compared human APP transgenic mice with (B254) and without (J20) the D664A mutation in a battery of tests. Before Abeta deposition, hAPP-B254 and hAPP-J20 mice had comparable hippocampal levels of Abeta(1-42). At 2-3 or 5-7 months of age, hAPP-B254 and hAPP-J20 mice had similar abnormalities relative to nontransgenic mice in spatial and nonspatial learning and memory, elevated plus maze performance, electrophysiological measures of synaptic transmission and plasticity, and levels of synaptic activity-related proteins. Thus, caspase cleavage of APP at position D664 and generation of C31 do not play a critical role in the development of these abnormalities.
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Affiliation(s)
- Julie A. Harris
- Gladstone Institute of Neurological Disease and
- Department of Neurology, University of California, San Francisco, San Francisco, California 94158
| | | | - Brian Halabisky
- Gladstone Institute of Neurological Disease and
- Department of Neurology, University of California, San Francisco, San Francisco, California 94158
| | - Iris Lo
- Gladstone Institute of Neurological Disease and
| | | | - Gui-Qiu Yu
- Gladstone Institute of Neurological Disease and
| | - Dale E. Bredesen
- Department of Neurology, University of California, San Francisco, San Francisco, California 94158
- Buck Institute for Age Research, Novato, California 94945, and
| | - Eliezer Masliah
- Departments of Neurosciences and Pathology, University of California, San Diego, San Diego, California 92093
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease and
- Department of Neurology, University of California, San Francisco, San Francisco, California 94158
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186
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Tizon B, Ribe EM, Mi W, Troy CM, Levy E. Cystatin C protects neuronal cells from amyloid-beta-induced toxicity. J Alzheimers Dis 2010; 19:885-94. [PMID: 20157244 PMCID: PMC2889175 DOI: 10.3233/jad-2010-1291] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Multiple studies suggest that cystatin C (CysC) has a role in Alzheimer's disease (AD) and a decrease in CysC secretion is linked to the disease in patients with a polymorphism in the CysC gene. CysC binds amyloid-beta (Abeta) and inhibits formation of Abeta fibrils and oligomers both in vitro and in mouse models of amyloid deposition. Here we studied the effect of CysC on cultured primary hippocampal neurons and a neuronal cell line exposed to either oligomeric or fibrillar cytotoxic forms of Abeta. The extracellular addition of the secreted human CysC together with preformed either oligomeric or fibrillar Abeta increased cell survival. While CysC inhibits Abeta aggregation, it does not dissolve preformed Abeta fibrils or oligomers. Thus, CysC has multiple protective effects in AD, by preventing the formation of the toxic forms of Abeta and by direct protection of neuronal cells from Abeta toxicity. Therapeutic manipulation of CysC levels, resulting in slightly higher concentrations than physiological could protect neuronal cells from cell death in AD.
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Affiliation(s)
- Belen Tizon
- Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Elena M. Ribe
- Departments of Pathology, Cell Biology and Neurology, Taub Center for the Study of Alzheimer's Disease and the Aging Brain, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Weiqian Mi
- Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Carol M. Troy
- Departments of Pathology, Cell Biology and Neurology, Taub Center for the Study of Alzheimer's Disease and the Aging Brain, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Efrat Levy
- Departments of Pharmacology and Psychiatry, New York University School of Medicine, Orangeburg, NY 10962, USA
- Nathan S. Kline Institute, Orangeburg, NY 10962, USA
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187
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Sealy JM, Truong AP, Tso L, Probst GD, Aquino J, Hom RK, Jagodzinska BM, Dressen D, Wone DW, Brogley L, John V, Tung JS, Pleiss MA, Tucker JA, Konradi AW, Dappen MS, Toth G, Pan H, Ruslim L, Miller J, Bova MP, Sinha S, Quinn KP, Sauer JM. Design and synthesis of cell potent BACE-1 inhibitors: Structure–activity relationship of P1′ substituents. Bioorg Med Chem Lett 2009; 19:6386-91. [DOI: 10.1016/j.bmcl.2009.09.061] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2009] [Revised: 09/14/2009] [Accepted: 09/16/2009] [Indexed: 11/16/2022]
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188
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Biochemical and immunohistochemical analysis of an Alzheimer's disease mouse model reveals the presence of multiple cerebral Abeta assembly forms throughout life. Neurobiol Dis 2009; 36:293-302. [PMID: 19660551 DOI: 10.1016/j.nbd.2009.07.021] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 07/07/2009] [Accepted: 07/25/2009] [Indexed: 11/23/2022] Open
Abstract
The amyloid beta-protein (Abeta) is believed to play a causal role in Alzheimer's disease, however, the mechanism by which Abeta mediates its effect and the assembly form(s) of Abeta responsible remain unclear. Several APP transgenic mice have been shown to accumulate Abeta and to develop cognitive deficits. We have studied one such model, the J20 mouse. Using an immunoprecipitation/Western blotting technique we find an age-dependent increase in Abeta monomer and SDS-stable dimer. But prior to the earliest detection of Abeta dimers, immunohistochemical analysis revealed an increase in oligomer immunoreactivity that was coincident with reduced hippocampal MAP2 and synaptophysin staining. Moreover, biochemical fractionation and ELISA analysis revealed evidence of TBS and triton-insoluble sedimentable Abeta aggregates at the earliest ages studied. These data demonstrate the presence of multiple assembly forms of Abeta throughout the life of J20 mice and highlight the difficulty in attributing synaptotoxicity to a single Abeta species.
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189
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Abstract
To investigate the role of human apolipoprotein E (apoE) on Abeta deposition in vivo, we crossed PDAPP mice lacking mouse Apoe to targeted replacement mice expressing human apoE (PDAPP/TRE2, PDAPP/TRE3, or PDAPP/TRE4). We then measured the levels of apoE protein and Abeta peptides in plasma, CSF, and brain homogenates in these mice at different ages. We also quantified the amount of brain Abeta and amyloid burden in 18-month-old mice. In young PDAPP/TRE4 mice that were analyzed at an age before brain Abeta deposition, we observed a significant decrease in the levels of apoE in CSF and brain when compared with age-matched mice expressing either human E2 or E3. The brain levels of Abeta42 in PDAPP/TRE4 mice were substantially elevated even at this very early time point. In older PDAPP/TRE4 mice, the levels of insoluble apoE protein increased in parallel to the dramatic rise in brain Abeta burden, and the majority of apoE was associated with Abeta. In TRE4 only mice, we also observed a significant decrease in the level of apoE in brain homogenates. Since the relative level of apoE mRNA was equivalent in PDAPP/TRE and TRE only mice, it appears that post-translational mechanisms influence the levels of apoE protein in brain (E4 < E3 << E2), resulting in early and dramatic apoE isoform-dependent effects on brain Abeta levels (E4 >> E3 > E2) that increase with age. Therapeutic strategies aimed at increasing the soluble levels of apoE protein, regardless of isoform, may effectively prevent and (or) treat Alzheimer's disease.
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190
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Suppression of amyloid deposition leads to long-term reductions in Alzheimer's pathologies in Tg2576 mice. J Neurosci 2009; 29:4964-71. [PMID: 19369565 DOI: 10.1523/jneurosci.4560-08.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In amyloid precursor protein (APP) models of amyloid deposition, the amount of amyloid deposits increase with mouse age. At a first approximation, the extent of amyloid accumulation may either reflect small excesses of production over clearance that accumulate over time or, alternatively, indicate a steady-state equilibrium at that age, reflecting the instantaneous excess of production over clearance, which increases as the organism ages. To discriminate between these options, we reversibly suppressed amyloid deposition in Tg2576 mice with the anti-Abeta antibody 2H6, starting at 8 months, just before the first histological deposits can be discerned. Six months later, we stopped the suppression and monitored the progression of amyloid accumulation in control APP mice and suppressed APP mice over the next 3 months. The accumulation hypothesis would predict that the rate of amyloid from 14 to 17 months would be similar in the suppressed and control mice, while the equilibrium hypothesis would predict that the increase would be faster in the suppressed group, possibly catching up completely with the control mice. The results strongly support the accumulation hypothesis, with no evidence of the suppressed mice catching up with the control mice as predicted by equilibrium models. If anything, there was a slower rate of increase in the suppressed APP mice than the control mice, suggesting that a slow seeding mechanism likely precedes a rapid fibrillogenesis in determining the extent of amyloid deposition.
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191
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Macrophage-mediated degradation of beta-amyloid via an apolipoprotein E isoform-dependent mechanism. J Neurosci 2009; 29:3603-12. [PMID: 19295164 DOI: 10.1523/jneurosci.5302-08.2009] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Recent studies suggest that bone marrow-derived macrophages can effectively reduce beta-amyloid (Abeta) deposition in brain. To further elucidate the mechanisms by which macrophages degrade Abeta, we cultured murine macrophages on top of Abeta plaque-bearing brain sections from transgenic mice expressing PDAPP [human amyloid precursor protein (APP) with the APP(717V>F) mutation driven by the platelet-derived growth factor promoter]. Using this ex vivo assay, we found that macrophages from wild-type mice very efficiently degrade both soluble and insoluble Abeta in a time-dependent manner and markedly eliminate thioflavine-S positive amyloid deposits. Because macrophages express and secrete apolipoprotein E (apoE), we compared the efficiency of Abeta degradation by macrophages prepared from apoE-deficient mice or mice expressing human apoE2, apoE3, or apoE4. Macrophages expressing apoE2 were more efficient at degrading Abeta than apoE3-expressing, apoE4-expressing, or apoE-deficient macrophages. Moreover, macrophage-induced degradation of Abeta was effectively blocked by an anti-apoE antibody and receptor-associated protein, an antagonist of the low-density lipoprotein (LDL) receptor family, suggesting involvement of LDL receptors. Measurement of matrix metalloproteinase-9 (MMP-9) activity in the media from human apoE-expressing macrophages cocultured with Abeta-containing brain sections revealed greater levels of MMP-9 activity in apoE2-expressing than in either apoE3- or apoE4-expressing macrophages. Differences in MMP-9 activity appear to contribute to the isoform-specific differences in Abeta degradation by macrophages. These apoE isoform-dependent effects of macrophages on Abeta degradation suggest a novel "peripheral" mechanism for Abeta clearance from brain that may also, in part, explain the isoform-dependent effects of apoE in determining the genetic risk for Alzheimer's disease.
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192
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Xia W, Yang T, Shankar G, Smith IM, Shen Y, Walsh DM, Selkoe DJ. A specific enzyme-linked immunosorbent assay for measuring beta-amyloid protein oligomers in human plasma and brain tissue of patients with Alzheimer disease. ACTA ACUST UNITED AC 2009; 66:190-9. [PMID: 19204155 DOI: 10.1001/archneurol.2008.565] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
OBJECTIVE To examine in vivo levels of beta-amyloid (Abeta) oligomers (oAbeta) vs monomeric Abeta in plasma and brain tissue of patients with sporadic and familial Alzheimer disease (AD) using a new enzyme-linked immunosorbent assay (ELISA) specific for oAbeta. DESIGN To establish the oAbeta ELISA, the same N-terminal Abeta antibody was used for antigen capture and detection. Plasma and postmortem brain tissue from patients with AD and control subjects were systematically analyzed by conventional monomeric Abeta and new oAbeta ELISAs. SUBJECTS We measured oAbeta species in plasma samples from 36 patients with clinically well-characterized AD and 10 control subjects. In addition, postmortem samples were obtained from brain autopsies of 9 patients with verified AD and 7 control subjects. MAIN OUTCOME MEASURES Oligomeric Abeta and 4 monomeric Abeta species in plasma samples from patients with AD and control subjects were measured by ELISA. RESULTS The specificity of the oAbeta ELISA was validated with a disulfide-crossed-linked, synthetic Abeta(1-40)Ser26Cys dimer that was specifically detected before but not after the dissociation of the dimers in beta-mercaptoethanol. Plasma assays showed that relative oAbeta levels were closely associated with relative Abeta(42) monomer levels across all of the subjects. Analysis of sequential plasma samples from a subset of the patients with AD, including a patient with AD caused by a presenilin mutation, revealed decreases in both oAbeta and Abeta(42) monomer levels over a 1- to 2-year period. In brain tissue from 9 patients with AD and 7 control subjects, both oAbeta and monomeric Abeta(42) levels were consistently higher in the AD cases. CONCLUSIONS An oAbeta-specific ELISA reveals a tight link between oAbeta and Abeta(42) monomer levels in plasma and brain. Both forms can decline over time in plasma, presumably reflecting their increasing insolubility in the brain.
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Affiliation(s)
- Weiming Xia
- Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, HIM 616, 77 Ave Louis Pasteur, Boston, MA 02115, USA.
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193
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Lord A, Englund H, Söderberg L, Tucker S, Clausen F, Hillered L, Gordon M, Morgan D, Lannfelt L, Pettersson FE, Nilsson LNG. Amyloid-beta protofibril levels correlate with spatial learning in Arctic Alzheimer's disease transgenic mice. FEBS J 2009; 276:995-1006. [PMID: 19215301 DOI: 10.1111/j.1742-4658.2008.06836.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Oligomeric assemblies of amyloid-beta (Abeta) are suggested to be central in the pathogenesis of Alzheimer's disease because levels of soluble Abeta correlate much better with the extent of cognitive dysfunctions than do senile plaque counts. Moreover, such Abeta species have been shown to be neurotoxic, to interfere with learned behavior and to inhibit the maintenance of hippocampal long-term potentiation. The tg-ArcSwe model (i.e. transgenic mice with the Arctic and Swedish Alzheimer mutations) expresses elevated levels of Abeta protofibrils in the brain, making tg-ArcSwe a highly suitable model for investigating the pathogenic role of these Abeta assemblies. In the present study, we estimated Abeta protofibril levels in the brain and cerebrospinal fluid of tg-ArcSwe mice, and also assessed their role with respect to cognitive functions. Protofibril levels, specifically measured with a sandwich ELISA, were found to be elevated in young tg-ArcSwe mice compared to several transgenic models lacking the Arctic mutation. In aged tg-ArcSwe mice with considerable plaque deposition, Abeta protofibrils were approximately 50% higher than in younger mice, whereas levels of total Abeta were exponentially increased. Young tg-ArcSwe mice showed deficits in spatial learning, and individual performances in the Morris water maze were correlated inversely with levels of Abeta protofibrils, but not with total Abeta levels. We conclude that Abeta protofibrils accumulate in an age-dependent manner in tg-ArcSwe mice, although to a far lesser extent than total Abeta. Our findings suggest that increased levels of Abeta protofibrils could result in spatial learning impairment.
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Affiliation(s)
- Anna Lord
- Department of Public Health and Caring Sciences/Molecular Geriatrics, Uppsala University, Sweden
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194
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Blanchard J, Decorte L, Noguès X, Micheau J. Characterization of cognition alteration across the course of the disease in APP751SL mice with parallel estimation of cerebral Abeta deposition. Behav Brain Res 2009; 201:147-57. [PMID: 19428628 DOI: 10.1016/j.bbr.2009.02.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Accepted: 02/04/2009] [Indexed: 11/26/2022]
Abstract
Current transgenic mouse models of Alzheimer disease constitute a relevant tool to examine the relationships between neuropathological lesions, neurodegeneration and clinical syndromes. Nevertheless, addressing the relation between Abeta deposition and cognition deterioration requires careful adjustment for age to decipher underlying mechanisms of impairments and identify potential therapeutic targets. In the present work we have carried out a detailed behavioral analysis of the APP(751SL) transgenic mouse model testing 6 age-points (from 2 to 19-20 months) and estimating in parallel the cerebral Abeta deposition. The immunohistochemistry study indicated a fast progression of Abeta(17-24) staining in several brain structures that reached for most of them, a maximal level at 7-8 months of age. Behavioral experiments showed that APP(751SL) mice displayed alterations in some general functions (muscular strength, motor activity) whereas other functions are preserved (anxiety, exploration). Acquisition and extinction of an appetitive operant conditioning were used to assess early learning deficits. Hippocampal but not dorso-lateral striatal lesion was shown to delay extinction. Although some learning deficits were detected at 5-6 months in the acquisition of the operant conditioning task, more robust impairments in extinction were observed in 7-8-month-old mice. Indeed, spatial memory deficit was associated to a selective hippocampal CA1 impairment of learning-induced Zif268 activation. Because this mouse model displayed gradual memory deficits it gives the opportunity to investigate the temporal progression of molecular and cellular mechanisms that induce cognitive decline.
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Affiliation(s)
- Julie Blanchard
- Centre for Integrative and Cognitive Neuroscience, University of Bordeaux, CNRS UMR 5228, Talence, France
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195
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Hemizygous minipigs produced by random gene insertion and handmade cloning express the Alzheimer’s disease-causing dominant mutation APPsw. Transgenic Res 2009; 18:545-58. [DOI: 10.1007/s11248-009-9245-4] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Accepted: 01/09/2009] [Indexed: 10/21/2022]
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196
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Sabbagh MN, Walker DG, Reid RT, Stadnick T, Anand K, Lue LF. Absence of effect of chronic nicotine administration on amyloid beta peptide levels in transgenic mice overexpressing mutated human APP (Sw, Ind). Neurosci Lett 2008; 448:217-20. [DOI: 10.1016/j.neulet.2008.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 10/01/2008] [Accepted: 10/01/2008] [Indexed: 11/26/2022]
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197
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Sun B, Zhou Y, Halabisky B, Lo I, Cho SH, Mueller-Steiner S, Devidze N, Wang X, Grubb A, Gan L. Cystatin C-cathepsin B axis regulates amyloid beta levels and associated neuronal deficits in an animal model of Alzheimer's disease. Neuron 2008; 60:247-57. [PMID: 18957217 DOI: 10.1016/j.neuron.2008.10.001] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 09/23/2008] [Accepted: 10/07/2008] [Indexed: 12/19/2022]
Abstract
Impaired degradation of amyloid beta (Abeta) peptides could lead to Abeta accumulation, an early trigger of Alzheimer's disease (AD). How Abeta-degrading enzymes are regulated remains largely unknown. Cystatin C (CysC, CST3) is an endogenous inhibitor of cysteine proteases, including cathepsin B (CatB), a recently discovered Abeta-degrading enzyme. A CST3 polymorphism is associated with an increased risk of late-onset sporadic AD. Here, we identified CysC as the key inhibitor of CatB-induced Abeta degradation in vivo. Genetic ablation of CST3 in hAPP-J20 mice significantly lowered soluble Abeta levels, the relative abundance of Abeta1-42, and plaque load. CysC removal also attenuated Abeta-associated cognitive deficits and behavioral abnormalities and restored synaptic plasticity in the hippocampus. Importantly, the beneficial effects of CysC reduction were abolished on a CatB null background, providing direct evidence that CysC regulates soluble Abeta and Abeta-associated neuronal deficits through inhibiting CatB-induced Abeta degradation.
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Affiliation(s)
- Binggui Sun
- Gladstone Institute of Neurological Disease, University of California San Francisco, San Francisco, CA 94158, USA
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198
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Yang T, Arslanova D, Gu Y, Augelli-Szafran C, Xia W. Quantification of gamma-secretase modulation differentiates inhibitor compound selectivity between two substrates Notch and amyloid precursor protein. Mol Brain 2008; 1:15. [PMID: 18983676 PMCID: PMC2637266 DOI: 10.1186/1756-6606-1-15] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Accepted: 11/04/2008] [Indexed: 11/23/2022] Open
Abstract
Background Deposition of amyloid-β protein (Aβ) is a major pathological hallmark of Alzheimer's disease (AD). Aβ is generated from γ-secretase cleavage of amyloid precursor protein (APP). In addition to APP, γ-secretase also cleaves other type I integral membrane proteins, including the Notch receptor, a key molecule involved in embryonic development. Results To explore selective γ-secretase inhibitors, a combination of five methods was used to systematically determine these inhibitors' profiles on the γ-secretase cleavage of APP and Notch. When two potent γ-secretase inhibitors, compound E (cpd E) and DAPT, were used in a conventional in vitro γ-secretase activity assay, cpd E completely blocked Aβ generation from the cleavage of substrate APP C100, but only had a minor effect on Notch cleavage and NICD generation. Next, cpd E and DAPT were applied to HEK293 cells expressing a truncated Notch substrate NotchΔE. Both cpd E and DAPT were more potent in blocking Aβ generation than NICD generation. Third, a reporter construct was created that carried the NICD targeting promoter with three Su(H) binding sequences followed by the luciferase gene. We found that the inhibition of NICD generation by cpd E and DAPT was consistent with the reduced expression of luciferase gene driven by this Notch targeting promoter. Fourth, levels of "Notch-Aβ-like" (Nβ*) peptide derived from two previously reported chimeric APP with its transmembrane domain or the juxtamembrane portion replaced by the Notch sequence were quantified. Measurement of Nβ* peptides by ELISA confirmed that EC50's of cpd E were much higher for Nβ* than Aβ. Finally, the expression levels of Notch target gene her6 in cpd E or DAPT-treated zebrafish were correlated with the degree of tail curvature due to defective somitogenesis, a well characterized Notch phenotype in zebrafish. Conclusion Our ELISA-based quantification of Aβ and Nβ* in combination with the test in zebrafish provides a novel approach for efficient cell-based screening and in vivo validation of APP selective γ-secretase inhibitors.
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Affiliation(s)
- Ting Yang
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard University, Boston, MA, USA.
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199
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Boche D, Zotova E, Weller RO, Love S, Neal JW, Pickering RM, Wilkinson D, Holmes C, Nicoll JAR. Consequence of Abeta immunization on the vasculature of human Alzheimer's disease brain. ACTA ACUST UNITED AC 2008; 131:3299-310. [PMID: 18953056 DOI: 10.1093/brain/awn261] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A major feature of Alzheimer's disease is the accumulation of amyloid-beta peptide (Abeta) in the brain both in the form of plaques in the cerebral cortex and in blood vessel as cerebral amyloid angiopathy (CAA). Experimental models and human clinical trials have shown that accumulation of Abeta plaques can be reversed by immunotherapy. In this study, we hypothesized that Abeta in plaques is solubilized by antibodies generated by immunization and drains via the perivascular pathway, detectable as an increase in cerebrovascular Abeta. We have performed a follow up study of Alzheimer's disease patients immunized against Abeta42. Neuropathological examination was performed on nine patients who died between four months and five years after their first immunization. Immunostaining for Abeta40 and Abeta42 was quantified and compared with that in unimmunized Alzheimer's disease controls (n = 11). Overall, compared with these controls, the group of immunized patients had approximately 14 times as many blood vessels containing Abeta42 in the cerebral cortex (P<0.001) and seven times more in the leptomeninges (P = 0.013); among the affected blood vessels in the immunized cases, most of them had full thickness and full circumference involvement of the vessel wall in the cortex (P = 0.001), and in the leptomeninges (P = 0.015). There was also a significantly higher level of cerebrovascular Abeta40 in the immunized cases than in the unimmunized cases (cortex: P = 0.009 and leptomeninges: P = 0.002). In addition, the immunized patients showed a higher density of cortical microhaemorrhages and microvascular lesions than the unimmunized controls, though none had major CAA-related intracerebral haemorrhages. The changes in cerebral vascular Abeta load did not appear to substantially influence the structural proteins of the blood vessels. Unlike most of the immunized patients, two of the longest survivors, four to five years after first immunization, had virtually complete absence of both plaques and CAA, raising the possibility that, given time, Abeta is eventually cleared from the cerebral vasculature. The findings are consistent with the hypothesis that Abeta immunization results in solubilization of plaque Abeta42 which, at least in part, exits the brain via the perivascular pathway, causing a transient increase in the severity of CAA. The extent to which these vascular alterations following Abeta immunization in Alzheimer's disease are reflected in changes in cognitive function remains to be determined.
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Affiliation(s)
- D Boche
- Division of Clinical Neurosciences, University of Southampton, Southampton General Hospital, Southampton, UK.
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200
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Miklossy J, Qing H, Radenovic A, Kis A, Vileno B, Làszló F, Miller L, Martins RN, Waeber G, Mooser V, Bosman F, Khalili K, Darbinian N, McGeer PL. Beta amyloid and hyperphosphorylated tau deposits in the pancreas in type 2 diabetes. Neurobiol Aging 2008; 31:1503-15. [PMID: 18950899 DOI: 10.1016/j.neurobiolaging.2008.08.019] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2008] [Revised: 08/23/2008] [Accepted: 08/25/2008] [Indexed: 01/21/2023]
Abstract
Strong epidemiologic evidence suggests an association between Alzheimer disease (AD) and type 2 diabetes. To determine if amyloid beta (Abeta) and hyperphosphorylated tau occurs in type 2 diabetes, pancreas tissues from 21 autopsy cases (10 type 2 diabetes and 11 controls) were analyzed. APP and tau mRNAs were identified in human pancreas and in cultured insulinoma beta cells (INS-1) by RT-PCR. Prominent APP and tau bands were detected by Western blotting in pancreatic extracts. Aggregated Abeta, hyperphosphorylated tau, ubiquitin, apolipoprotein E, apolipoprotein(a), IB1/JIP-1 and JNK1 were detected in Langerhans islets in type 2 diabetic patients. Abeta was co-localized with amylin in islet amyloid deposits. In situ beta sheet formation of islet amyloid deposits was shown by infrared microspectroscopy (SIRMS). LPS increased APP in non-neuronal cells as well. We conclude that Abeta deposits and hyperphosphorylated tau are also associated with type 2 diabetes, highlighting common pathogenetic features in neurodegenerative disorders, including AD and type 2 diabetes and suggesting that Abeta deposits and hyperphosphorylated tau may also occur in other organs than the brain.
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Affiliation(s)
- Judith Miklossy
- Kinsmen Laboratory of Neurological Research, University of British Columbia, Vancouver, BC, Canada.
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