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Uversky VN, Eliezer D. Biophysics of Parkinson's disease: structure and aggregation of alpha-synuclein. Curr Protein Pept Sci 2009; 10:483-99. [PMID: 19538146 PMCID: PMC3786709 DOI: 10.2174/138920309789351921] [Citation(s) in RCA: 243] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 02/05/2009] [Indexed: 12/21/2022]
Abstract
Parkinson's disease (PD) is a slowly progressive movement disorder that results from the loss of dopaminergic neurons in the substantia nigra, a small area of cells in the mid-brain. PD is a multifactorial disorder with unknown etiology, in which both genetic and environmental factors play important roles. Substantial evidence links alpha-synuclein, a small highly conserved presynaptic protein with unknown function, to both familial and sporadic PD. Rare familial cases of PD are associated with missense point mutations in alpha-synuclein, or with the hyper-expression of the wild type protein due to its gene duplication/triplication. Furthermore, alpha-synuclein was identified as the major component of amyloid fibrils found in Lewy body and Lewy neurites, the characteristic proteinaceous deposits that are the diagnostic hallmarks of PD. alpha-Synuclein is abundant in various regions of the brain and has two closely related homologs, beta-synuclein and gamma-synuclein. When isolated in solution, the protein is intrinsically disordered, but in the presence of lipid surfaces alpha-synuclein adopts a highly helical structure that is believed to mediate its normal function(s). A number of different conformational states of alpha-synuclein have been observed. Besides the membrane-bound form, other critical conformations include a partially-folded state that is a key intermediate in aggregation and fibrillation, various oligomeric species, and fibrillar and amorphous aggregates. A number of intrinsic and extrinsic factors that either accelerate or inhibit the rate of alpha-synuclein aggregation and fibrillation in vitro are known. There is a strong correlation between the conformation of alpha-synuclein (induced by various factors) and its rate of fibrillation. The aggregation process appears to be branched, with one pathway leading to fibrils and another to oligomeric intermediates that may ultimately form amorphous deposits. The molecular basis of Parkinson's disease appears to be tightly coupled to the aggregation of alpha-synuclein and the factors that affect its conformation. This review focuses on the contributions of Prof. Anthony L. Fink to the field and presents some recent developments in this exciting area.
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Affiliation(s)
- Vladimir N. Uversky
- Institite for Intrinsically Disordered Protein Research, Center for Computational Biology and Bioinformatics, Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Institute for Biological Instrumentation, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
| | - David Eliezer
- Department of Biochemistry and Program in Structural Biology, Weill Cornell Medical College, New York, New York 10021, USA
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102
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Sanchez-Ortiz E, Hahm BK, Armstrong DL, Rossie S. Protein phosphatase 5 protects neurons against amyloid-beta toxicity. J Neurochem 2009; 111:391-402. [PMID: 19686245 DOI: 10.1111/j.1471-4159.2009.06337.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyloid-beta (Abeta) is thought to promote neuronal cell loss in Alzheimer's disease, in part through the generation of reactive oxygen species (ROS) and subsequent activation of mitogen-activated protein kinase (MAPK) pathways. Protein phosphatase 5 (PP5) is a ubiquitously expressed serine/threonine phosphatase which has been implicated in several cell stress response pathways and shown to inactivate MAPK pathways through key dephosphorylation events. Therefore, we examined whether PP5 protects dissociated embryonic rat cortical neurons in vitro from cell death evoked by Abeta. As predicted, neurons in which PP5 expression was decreased by small-interfering RNA treatment were more susceptible to Abeta toxicity. In contrast, over-expression of PP5, but not the inactive mutant, PP5(H304Q), prevented MAPK phosphorylation and neurotoxicity induced by Abeta. PP5 also prevented cell death caused by direct treatment with H(2)O(2), but did not prevent Abeta-induced production of ROS. Thus, the neuroprotective effect of PP5 requires its phosphatase activity and lies downstream of Abeta-induced generation of ROS. In summary, our data indicate that PP5 plays a pivotal neuroprotective role against cell death induced by Abeta and oxidative stress. Consequently, PP5 might be an effective therapeutic target in Alzheimer's disease and other neurodegenerative disorders in which oxidative stress is implicated.
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Affiliation(s)
- Efrain Sanchez-Ortiz
- Department of Biochemistry and Purdue Cancer Center, Purdue University, West Lafayette, Indiana 47907, USA
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103
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Sciarabba M, Serrao G, Bauer D, Arnaboldi F, Borghese N. Automatic detection of neurons in large cortical slices. J Neurosci Methods 2009; 182:123-40. [DOI: 10.1016/j.jneumeth.2009.05.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 05/14/2009] [Accepted: 05/27/2009] [Indexed: 11/26/2022]
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104
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Garcia-Alloza M, Subramanian M, Thyssen D, Borrelli LA, Fauq A, Das P, Golde TE, Hyman BT, Bacskai BJ. Existing plaques and neuritic abnormalities in APP:PS1 mice are not affected by administration of the gamma-secretase inhibitor LY-411575. Mol Neurodegener 2009; 4:19. [PMID: 19419556 PMCID: PMC2687427 DOI: 10.1186/1750-1326-4-19] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 05/06/2009] [Indexed: 11/10/2022] Open
Abstract
The gamma-secretase complex is a major therapeutic target for the prevention and treatment of Alzheimer's disease. Previous studies have shown that treatment of young APP mice with specific inhibitors of gamma-secretase prevented formation of new plaques. It has not yet been shown directly whether existing plaques would be affected by gamma-secretase inhibitor treatment. Similarly, alterations in neuronal morphology in the immediate vicinity of plaques represent a plaque-specific neurotoxic effect. Reversal of these alterations is an important endpoint of successful therapy whether or not a treatment affects plaque size. In the present study we used longitudinal imaging in vivo with multiphoton microscopy to study the effects of the orally active gamma-secretase inhibitor LY-411575 in 10-11 month old APP:PS1 mice with established amyloid pathology and neuritic abnormalities. Neurons expressed YFP allowing fluorescent detection of morphology whereas plaques were labelled with methoxy-XO4. The same identified neurites and plaques were followed in weekly imaging sessions in living mice treated daily (5 mg/kg) for 3 weeks with the compound. Although LY-411575 reduced Abeta levels in plasma and brain, it did not have an effect on the size of existing plaques. There was also no effect on the abnormal neuritic curvature near plaques, or the dystrophies in very close proximity to senile plaques. Our results suggest that therapeutics aimed at inhibition of Abeta generation are less effective for reversal of existing plaques than for prevention of new plaque formation and have no effect on the plaque-mediated neuritic abnormalities, at least under these conditions where Abeta production is suppressed but not completely blocked. Therefore, a combination therapy of Abeta suppression with agents that increase clearance of amyloid and/or prevent neurotoxicity might be needed for a more effective treatment in patients with pre-existing pathology.
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Affiliation(s)
- Monica Garcia-Alloza
- MassGeneral Institute for Neurodegenerative Diseases, Massachusetts General Hospital, 114 16th Street, Charlestown, MA 02129, USA.
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105
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Faure A, Verret L, Bozon B, El Tannir El Tayara N, Ly M, Kober F, Dhenain M, Rampon C, Delatour B. Impaired neurogenesis, neuronal loss, and brain functional deficits in the APPxPS1-Ki mouse model of Alzheimer's disease. Neurobiol Aging 2009; 32:407-18. [PMID: 19398247 DOI: 10.1016/j.neurobiolaging.2009.03.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 03/17/2009] [Accepted: 03/18/2009] [Indexed: 12/18/2022]
Abstract
Amyloid-β peptide species accumulating in the brain of patients with Alzheimer's disease are assumed to have a neurotoxic action and hence to be key actors in the physiopathology of this neurodegenerative disease. We have studied a new mouse mutant (APPxPS1-Ki) line developing both early-onset brain amyloid-β deposition and, in contrast to most of transgenic models, subsequent neuronal loss. In 6-month-old mice, we observed cell layer atrophies in the hippocampus, together with a dramatic decrease in neurogenesis and a reduced brain blood perfusion as measured in vivo by magnetic resonance imaging. In these mice, neurological impairments and spatial hippocampal dependent memory deficits were also substantiated and worsened with aging. We described here a phenotype of APPxPS1-Ki mice that summarizes several neuroanatomical alterations and functional deficits evocative of the human pathology. Such a transgenic model that displays strong face validity might be highly beneficial to future research on AD physiopathogeny and therapeutics.
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Affiliation(s)
- A Faure
- CNRS, Lab NAMC, UMR8620, Université Paris Sud, 91405, Orsay, France.
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106
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Chiang HC, Iijima K, Hakker I, Zhong Y. Distinctive roles of different beta-amyloid 42 aggregates in modulation of synaptic functions. FASEB J 2009; 23:1969-77. [PMID: 19255256 DOI: 10.1096/fj.08-121152] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To determine how endogenously secreted beta-amyloid 42 (Abeta42) aggregates regulate synaptic functions, we examined effects of Abeta42 at the neuromuscular junction of Drosophila larvae. Voltage-clamp recordings of synaptic transmission and optical analysis of vesicle recycling at presynaptic terminals show that expression of Abeta42 in neurons leads to a reduction of neurotransmitter release. However, expression of Abeta42 in postsynaptic muscle cells enhanced neurotransmitter release. Both effects are neutralized by Abeta antibody, suggesting a role for secreted Abeta42 peptides. Application of exogenously prepared Abeta42 oligomers leads to a reduction in synaptic responses, whereas mixed Abeta42 aggregates with mainly fibrils elicit an opposite effect by increasing synaptic transmission. Further analysis of long-term depression (LTD) confirms differential effects of different Abeta42 aggregates. Taken together, our data suggest that Abeta42 is secreted from neurons primarily as oligomers that inhibit neurotransmitter release and exert no effect on LTD. Whereas larger-sized aggregates, possibly fibrils, are major components secreted from muscle cells, which enhance synaptic transmission and LTD. Thus, different types of cells may secrete distinct forms of Abeta42 aggregates, leading to different modulation of synaptic functions.
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Affiliation(s)
- Hsueh-Cheng Chiang
- Cold Spring Harbor Laboratory, P.O. Box 100, Cold Spring Harbor, NY 11724, USA
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107
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Affiliation(s)
- Bruce A Yankner
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA.
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108
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Garcia-Alloza M, Borrelli LA, Hyman BT, Bacskai BJ. Antioxidants have a rapid and long-lasting effect on neuritic abnormalities in APP:PS1 mice. Neurobiol Aging 2009; 31:2058-68. [PMID: 19124175 DOI: 10.1016/j.neurobiolaging.2008.11.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 09/23/2008] [Accepted: 11/08/2008] [Indexed: 01/10/2023]
Abstract
Senile plaques are a major pathological hallmark of Alzheimer's disease (AD). Compelling evidence suggests that senile plaques lead to structural alterations of neuronal processes and that local toxicity may be mediated by increased oxidative stress. Anti-oxidant therapy can alleviate the neuronal abnormalities in APP mice, but the time-course of this beneficial effect is unknown. We used multiphoton microscopy to assess in vivo the characteristics of antioxidant treatment on senile plaques and neurites in AD model mice (APPswe/PS1dE9). We observed that α-phenyl-N-tert-butyl nitrone (PBN), Ginkgo biloba extract (EGb 761) and Trolox had no effect on the size of existing senile plaques. However, all anti-oxidants had a straightening effect on curved neurites. This effect was detected as soon as 4 days after commencing the treatment, and was maintained after 1 month of daily treatment, with no further increase in the effect. The straightening of neurites persisted 15 days after stopping the treatment. These data indicate that neuronal plasticity is fast and still active in adult animals, and suggest that amelioration of the neuritic distortions associated with senile plaques with antioxidants is both rapid and long lasting.
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Affiliation(s)
- Monica Garcia-Alloza
- Massachusetts General Hospital, Department of Neurology/Alzheimer's Disease Research Laboratory, 114 16th Street, Charlestown, MA 02129, USA
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109
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Hong DP, Fink AL, Uversky VN. Smoking and Parkinson's disease: does nicotine affect alpha-synuclein fibrillation? BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1794:282-90. [PMID: 19013262 DOI: 10.1016/j.bbapap.2008.09.026] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Revised: 09/09/2008] [Accepted: 09/29/2008] [Indexed: 11/19/2022]
Abstract
alpha-synuclein is a small presynaptic protein (14,460 D) that is abundantly distributed in the brain. Although, its function is unknown, the aggregated form of alpha-synuclein is a pathological hallmark of several neurodegenerative diseases, including Parkinson's disease (PD). Epidemiological studies have shown that smoking can lessen the incidence of Parkinson's disease, indicating that smoke may contain chemicals that are neuro-protective. The fibrillation of alpha-synuclein was studied in relation to five different compounds found in cigarette smoke: anabasine, cotinine, hydroquinone, nicotine and nornicotine. Thioflavin T assays, gel electrophoresis, size exclusion chromatography-high performance liquid chromatography (SEC-HPLC) and atomic force microscopy (AFM) were utilized to monitor the rate of alpha-synuclein fibrillation and the inhibitory effects of the cigarette smoke components. We show that nicotine and hydroquinone inhibit alpha-synuclein fibril formation in a concentration-dependent manner, with nicotine being more effective. The SEC-HPLC data show that nicotine and hydroquinone stabilize soluble oligomers. The morphology of the oligomers stabilized by nicotine was evaluated by AFM, which showed the presence of three stable oligomers with an average height of 16 nm, 10 nm and 4 nm. Comparable results were obtained for the effect of the cigarette smoke components on the A53T mutant fibrillation. These results show that nicotine and hydroquinone inhibit alpha-synuclein fibrillation and stabilize soluble oligomeric forms. This information can be used to understand the molecular mechanism of the nicotine and hydroquinone action to develop therapeutic solutions for PD.
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Affiliation(s)
- Dong-Pyo Hong
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, California 95064, USA
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110
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Structural characteristics of alpha-synuclein oligomers stabilized by the flavonoid baicalein. J Mol Biol 2008; 383:214-23. [PMID: 18775438 DOI: 10.1016/j.jmb.2008.08.039] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Accepted: 08/15/2008] [Indexed: 11/23/2022]
Abstract
The flavonoid baicalein inhibits fibrillation of alpha-synuclein, which is a major component of Lewy bodies in Parkinson's disease. It has been known that baicalein induces the formation of alpha-synuclein oligomers and consequently prevents their fibrillation. In order to evaluate the structural properties of baicalein-stabilized oligomers, we purified oligomer species by HPLC and examined their stability and structure by CD, Fourier transform infrared spectroscopy, size exclusion chromatography HPLC, small-angle X-ray scattering, and atomic force microscopy. Baicalein-stabilized oligomers are beta-sheet-enriched according to CD and Fourier transform infrared spectroscopy analyses. They did not form fibrils even after very prolonged incubation. From small-angle X-ray scattering data and atomic force microscopy images, the oligomers were characterized as quite compact globular species. Oligomers were extremely stable, with a GdmCl C(m)=3.3 M. This high stability explains the previously observed inhibition properties of baicalein against alpha-synuclein fibrillation. These baicalein-stabilized oligomers, added to the solution of aggregating alpha-synuclein, were able to noticeably inhibit its fibrillation. After prolonged coincubation, short fibrils were formed, suggesting an effective interaction of oligomers with monomeric alpha-synuclein. Membrane permeability tests suggested that the baicalein-stabilized oligomers had a mild effect on the integrity of the membrane surface. This effect was rather similar to that of the monomeric protein, suggesting that targeted stabilization of certain alpha-synuclein oligomers might offer a potential strategy for the development of novel Parkinson's disease therapies.
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111
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Rocher AB, Kinson MS, Luebke JI. Significant structural but not physiological changes in cortical neurons of 12-month-old Tg2576 mice. Neurobiol Dis 2008; 32:309-18. [PMID: 18721884 DOI: 10.1016/j.nbd.2008.07.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Revised: 06/26/2008] [Accepted: 07/25/2008] [Indexed: 11/29/2022] Open
Abstract
Amyloid-beta (Abeta) plays a key role in the etiology of Alzheimer's disease, and pyramidal cell dendrites exposed to Abeta exhibit dramatic structural alterations, including reduced dendritic spine densities. To determine whether such structural alterations lead to electrophysiological changes, whole-cell patch clamp recordings with biocytin filling were used to assess both the electrophysiological and morphological properties of layer 3 pyramidal cells in frontal cortical slices prepared from 12-month-old Tg2576 amyloid precursor protein (APP) mutant vs. wild-type (Wt) mice. Tg2576 cells exhibited significantly increased dendritic lengths and volumes and decreased spine densities, while the total number of spines was not different from Wt. Tg2576 and Wt cells did not differ with regard to passive membrane, action potential firing or glutamatergic spontaneous excitatory postsynaptic current properties. Thus, overexpression of mutated APP in young Tg2576 mice leads to significant changes in neuronal morphological properties which do not have readily apparent functional consequences.
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Affiliation(s)
- Anne B Rocher
- Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA 02118, USA
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112
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Inglis A, Cruz L, Roe DL, Stanley HE, Rosene DL, Urbanc B. Automated identification of neurons and their locations. J Microsc 2008; 230:339-52. [PMID: 18503659 DOI: 10.1111/j.1365-2818.2008.01992.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Individual locations of many neuronal cell bodies (>10(4)) are needed to enable statistically significant measurements of spatial organization within the brain such as nearest-neighbour and microcolumnarity measurements. In this paper, we introduce an Automated Neuron Recognition Algorithm (ANRA) which obtains the (x, y) location of individual neurons within digitized images of Nissl-stained, 30 microm thick, frozen sections of the cerebral cortex of the Rhesus monkey. Identification of neurons within such Nissl-stained sections is inherently difficult due to the variability in neuron staining, the overlap of neurons, the presence of partial or damaged neurons at tissue surfaces, and the presence of non-neuron objects, such as glial cells, blood vessels, and random artefacts. To overcome these challenges and identify neurons, ANRA applies a combination of image segmentation and machine learning. The steps involve active contour segmentation to find outlines of potential neuron cell bodies followed by artificial neural network training using the segmentation properties (size, optical density, gyration, etc.) to distinguish between neuron and non-neuron segmentations. ANRA positively identifies 86 +/- 5% neurons with 15 +/- 8% error (mean +/- SD) on a wide range of Nissl-stained images, whereas semi-automatic methods obtain 80 +/- 7%/17 +/- 12%. A further advantage of ANRA is that it affords an unlimited increase in speed from semi-automatic methods, and is computationally efficient, with the ability to recognize approximately 100 neurons per minute using a standard personal computer. ANRA is amenable to analysis of huge photo-montages of Nissl-stained tissue, thereby opening the door to fast, efficient and quantitative analysis of vast stores of archival material that exist in laboratories and research collections around the world.
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Affiliation(s)
- A Inglis
- Center for Polymer Studies, Department of Physics, Boston University, Boston, MA 02215, USA.
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113
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Paulson JB, Ramsden M, Forster C, Sherman MA, McGowan E, Ashe KH. Amyloid plaque and neurofibrillary tangle pathology in a regulatable mouse model of Alzheimer's disease. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 173:762-72. [PMID: 18669616 DOI: 10.2353/ajpath.2008.080175] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Transgenic mouse models that independently express mutations in amyloid precursor protein (APP) and tau have proven useful for the study of the neurological consequences of amyloid-beta (Abeta) plaque and neurofibrillary tangle pathologies. Studies using these mice have yielded essential discoveries with regard to specific aspects of neuronal dysfunction and degeneration that characterize the brain during Alzheimer's disease (AD) and other age-dependent tauopathies. Most recent transgenic studies have focused on the creation of regulatable models that allow the temporal control of transgene expression. To study a more complete model of AD pathology, we designed a new regulatable transgenic mouse that harbors both APP and tau transgenes. Here, we present a novel transgenic mouse model, rTg3696AB, which expresses human APP(NLI) and tau(P301L) driven by the CaMKII promoter system. Subsequent generation of Abeta and 4R0N tau in the brain resulted in the development of three neuropathological features of AD: Abeta plaques, neurofibrillary tangles, and neurodegeneration. Importantly, transgene expression in these mice is regulatable, permitting temporal control of gene expression and the investigation of transgene suppression.
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Affiliation(s)
- Jennifer B Paulson
- Department of Neurology, University of Minnesota Medical School, 420 Delaware St. SE, Minneapolis, MN 55127, USA
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114
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Abstract
Aggregation and subsequent development of protein deposition diseases originate from conformational changes in corresponding amyloidogenic proteins. The accumulated data support the model where protein fibrillogenesis proceeds via the formation of a relatively unfolded amyloidogenic conformation, which shares many structural properties with the pre-molten globule state, a partially folded intermediate first found during the equilibrium and kinetic (un)folding studies of several globular proteins and later described as one of the structural forms of natively unfolded proteins. The flexibility of this structural form is essential for the conformational rearrangements driving the formation of the core cross-beta structure of the amyloid fibril. Obviously, molecular mechanisms describing amyloidogenesis of ordered and natively unfolded proteins are different. For ordered protein to fibrillate, its unique and rigid structure has to be destabilized and partially unfolded. On the other hand, fibrillogenesis of a natively unfolded protein involves the formation of partially folded conformation; i.e., partial folding rather than unfolding. In this review recent findings are surveyed to illustrate some unique features of the natively unfolded proteins amyloidogenesis.
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Affiliation(s)
- Vladimir N Uversky
- Department of Biochemistry and Molecular Biology, Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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115
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Lee JS, Um E, Park JK, Park CB. Microfluidic self-assembly of insulin monomers into amyloid fibrils on a solid surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:7068-7071. [PMID: 18549255 DOI: 10.1021/la800907c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We report the self-assembly of insulin monomers into amyloid fibrils within microchannels. To demonstrate the microfluidic amyloid formation and fibril growth on a solid surface, we seeded the internal surfaces of the microchannels with insulin monomers via N-hydroxysuccinimide ester activation and continuously flushed a fresh insulin solution through the microchannels. According to our analysis using optical and fluorescence microscopy, insulin amyloid preferentially formed in the center of the microchannels and, after reaching a certain density, spread to the side walls of the microchannels. By using ex situ atomic force microscopy, we observed the growth of amyloid fibrils inside the microchannels, which occurred at a much higher rate than that in bulk systems. After 12 h of incubation, insulin formed amyloid spherulites having "Maltese cross" extinction patterns within the microchannels according to the polarized microscopic analysis. Microfluidic amyloid formation enabled low consumption of reagents, reduction of incubation time, and simultaneous observation of amyloid formation under different conditions. This work will contribute to the rapid analysis of amyloid formation associated with many protein misfolding diseases.
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Affiliation(s)
- Joon Seok Lee
- Department of Materials Science and Engineering, and Department of Bio and Brain Engineering, KAIST, 335 Gwahangno, Daejeon 305-701, Republic of Korea
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116
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Cassel JC, Mathis C, Majchrzak M, Moreau PH, Dalrymple-Alford JC. Coexisting cholinergic and parahippocampal degeneration: a key to memory loss in dementia and a challenge for transgenic models? NEURODEGENER DIS 2008; 5:304-17. [PMID: 18520165 DOI: 10.1159/000135615] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Accepted: 10/31/2007] [Indexed: 12/25/2022] Open
Abstract
One century after Alzheimer's initial report, a variety of animal models of Alzheimer's disease (AD) are being used to mimic one or more pathological signs viewed as critical for the evolution of cognitive decline in dementia. Among the most common are, (a) traditional lesion models aimed at reproducing the degeneration of one of two key brain regions affected in AD, namely the cholinergic basal forebrain (CBF) and the transentorhinal region, and (b) transgenic mouse models aimed at reproducing AD histopathological hallmarks, namely amyloid plaques and neurofibrillary tangles. These models have provided valuable insights into the development and consequences of the pathology, but they have not consistently reproduced the severity of memory deficits exhibited in AD. The reasons for this lack of correspondence with the severity of expected deficits may include the limited replication of multiple neuropathology in potentially key brain regions. A recent lesion model in the rat found that severe memory impairment was obtained only when the two traditional lesions were combined together (i.e. conjoint CBF and entorhinal cortex lesions), indicative of a dramatic impact on cognitive function when there is coexisting, rather than isolated, damage in these two brain regions. It is proposed that combining AD transgenic mouse models with additional experimental damage to both the CBF and entorhinal regions might provide a unique opportunity to further understand the evolution of the disease and improve treatments of severe cognitive dysfunction in neurodegenerative dementias.
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Affiliation(s)
- Jean-Christophe Cassel
- LINC UMR 7191, Université Louis Pasteur, CNRS, Institut Fédératif de Recherche IFR 37, GDR CNRS 2905, Strasbourg, France.
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117
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Wirths O, Breyhan H, Schäfer S, Roth C, Bayer TA. Deficits in working memory and motor performance in the APP/PS1ki mouse model for Alzheimer's disease. Neurobiol Aging 2008; 29:891-901. [PMID: 17215062 DOI: 10.1016/j.neurobiolaging.2006.12.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Revised: 11/23/2006] [Accepted: 12/11/2006] [Indexed: 10/23/2022]
Abstract
The APP/PS1ki mouse model for Alzheimer's disease (AD) exhibits robust brain and spinal cord axonal degeneration and hippocampal CA1 neuron loss starting at 6 months of age. It expresses human mutant APP751 with the Swedish and London mutations together with two FAD-linked knocked-in mutations (PS1 M233T and PS1 L235P) in the murine PS1 gene. The present report covers a phenotypical analysis of this model using either behavioral tests for working memory and motor performance, as well as an analysis of weight development and body shape. At the age of 6 months, a dramatic, age-dependent change in all of these properties and characteristics was observed, accompanied by a significantly reduced ability to perform working memory and motor tasks. The APP/PS1ki mice were smaller and showed development of a thoracolumbar kyphosis, together with an incremental loss of body weight. While 2-month-old APP/PS1ki mice were inconspicuous in all of these tasks and properties, there is a massive age-related impairment in all tested behavioral paradigms. We have previously reported robust axonal degeneration in brain and spinal cord, as well as abundant hippocampal CA1 neuron loss starting at 6 months of age in the APP/PS1ki mouse model, which coincides with the onset of motor and memory deficits described in the present report.
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Affiliation(s)
- Oliver Wirths
- Department of Psychiatry, University of Goettingen, von-Siebold-Str. 5, D-37075 Goettingen, Germany.
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118
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Cotel MC, Bayer TA, Wirths O. Age-dependent loss of dentate gyrus granule cells in APP/PS1KI mice. Brain Res 2008; 1222:207-13. [PMID: 18585693 DOI: 10.1016/j.brainres.2008.05.052] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Revised: 05/14/2008] [Accepted: 05/17/2008] [Indexed: 12/16/2022]
Abstract
Loss of neurons in the hippocampus and other brain regions is, besides the occurrence of plaques and tangles, a neuropathological feature of Alzheimer's disease (AD). In recent years a plethora of transgenic mouse models overexpressing mutant amyloid precursor protein (APP) has been developed, which represent valuable research tools. Whereas extracellular plaque pathology is a common feature of these models, neuronal loss is a rather rare characteristic. In the present study, we quantified the number of neurons in the dentate gyrus granule layer (GCL) in 2- and 12-month-old APP/PS1KI mice, a mouse model that has been previously shown to have significant loss of neurons in the CA1 layer of the hippocampus. Stereological analysis revealed a strongly significant decrease of GCLs in aged APP/PS1KI mice, compared to age-matched PS1KI control animals (-44%), however, the volume of the GCL was not different.
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Affiliation(s)
- Marie-Caroline Cotel
- Division of Molecular Psychiatry and Alzheimer Ph.D. Graduate School, Department of Psychiatry, University of Goettingen, von-Siebold-Strasse 5, Goettingen, Germany
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119
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Radde R, Duma C, Goedert M, Jucker M. The value of incomplete mouse models of Alzheimer's disease. Eur J Nucl Med Mol Imaging 2008; 35 Suppl 1:S70-4. [PMID: 18270700 DOI: 10.1007/s00259-007-0704-y] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
To study Alzheimer's disease (AD), a variety of mouse models has been generated through the overexpression of the amyloid precursor protein and/or the presenilins harboring one or several mutations found in familial AD. With aging, these mice develop several lesions similar to those of AD, including diffuse and neuritic amyloid deposits, cerebral amyloid angiopathy, dystrophic neurites and synapses, and amyloid-associated neuroinflammation. Other characteristics of AD, such as neurofibrillary tangles and nerve cell loss, are not satisfactorily reproduced in these models. Mouse models that recapitulate only specific aspects of AD pathogenesis are of great advantage when deciphering the complexity of the disease and can contribute substantially to diagnostic and therapeutic innovations. Incomplete mouse models have been key to the development of Abeta42-targeted therapies, as well as to the current understanding of the interrelationship between cerebral beta-amyloidosis and tau neurofibrillary lesions, and are currently being used to develop novel diagnostic agents for in vivo imaging.
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Affiliation(s)
- Rebecca Radde
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Otfried-Müller Strasse 27, Tübingen, Germany.
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120
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Abstract
Aging is accompanied by cognitive decline in a major segment of the population and is the primary risk factor for Alzheimer's disease and other prevalent neurodegenerative disorders. Despite this central role in disease pathogenesis and morbidity, the aging of the brain has not been well understood at a molecular level. This review seeks to integrate what is known about age-related cognitive and neuroanatomical changes with recent advances in understanding basic molecular mechanisms that underlie aging. An important issue is how normal brain aging transitions to pathological aging, giving rise to neurodegenerative disorders. Toxic protein aggregates have been identified as potential contributory factors, including amyloid beta-protein in Alzheimer's disease, tau in frontotemporal dementia, and alpha-synuclein in Parkinson's disease. However, current models of pathogenesis do not explain the origin of the common sporadic forms of these diseases or address the critical nexus between aging and disease. This review discusses potential approaches to unifying the systems biology of the aging brain with the pathogenesis of neurodegeneration.
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Affiliation(s)
- Bruce A Yankner
- Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.
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121
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Kumar-Singh S. Cerebral amyloid angiopathy: pathogenetic mechanisms and link to dense amyloid plaques. GENES BRAIN AND BEHAVIOR 2008; 7 Suppl 1:67-82. [PMID: 18184371 DOI: 10.1111/j.1601-183x.2007.00380.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Cerebral amyloid angiopathy (CAA) of the amyloid-beta (Abeta) type is the most common form of sporadic CAA and is now also accepted as an early and integral part of Alzheimer's disease (AD) pathogenesis. Cerebral amyloid angiopathy is a risk factor for haemorrhagic stroke and is believed to independently contribute to dementia. Rare forms of hereditary cerebral amyloidosis caused by mutations within the Abeta domain of amyloid precursor protein (APP) have been identified, where mutant Abeta preferably deposits in vessels because of a decreased fibrillogenic potential and/or increased vasotopicity. A review of factors involved in CAA caused by wild-type Abeta suggests that increased Abeta levels in brain without an increased Abeta42/Abeta40 ratio is one of the most important prerequisites for vascular amyloidosis. This is exemplified by CAA observed in APP duplication and Down's syndrome patients, neprilysin polymorphism patients and knockout mice and Swedish APP (KM670/671NL) mice. Select presenilin mutations also lead to a prominent CAA, and importantly, presenilin mutations are shown to have varied effects on the production of Abeta40, the predominant amyloid found in CAA. Conversely, APP mutations such as Austrian APP (T714I) drastically decrease Abeta40 production and are deficient in CAA. Apolipoprotein E-epsilon4 is also shown to be a risk factor for CAA, and this might be because of its specific role in the aggregation of Abeta40. Recent data also suggest that dense-core senile plaques in humans and dense plaques in transgenic mice, composed predominantly of Abeta40, associate with vessels. This review highlights some of these aspects of genetics and biochemistry of CAA and pathological descriptions linked to a prominent CAA and/or dense plaques in humans and relevant mouse models and discusses how this knowledge has led to a better understanding of the processes involved in vascular amyloidosis, and in causing dementia, and thus has important therapeutic implications.
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Affiliation(s)
- S Kumar-Singh
- Neurodegenerative Brain Diseases Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerpen, Belgium.
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122
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Limited clearance of pre-existing amyloid plaques after intracerebral injection of Abeta antibodies in two mouse models of Alzheimer disease. J Neuropathol Exp Neurol 2008; 67:30-40. [PMID: 18091561 DOI: 10.1097/nen.0b013e31815f38d2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Recent studies have demonstrated the potential utility of antibodies for the treatment of Alzheimer disease (AD). In transgenic mouse models of AD, peripheral and intracerebral administration of Abeta-specific antibodies reduces amyloid burdens to varied extents. The mechanism may involve clearance of pre-existing amyloid plaques or prevention of new amyloid formation. Here, we have used two transgenic models, the inducible CamKII-ttAxtetAPP/swe/ind (Line 107) and the APPswe/PS1dE9 (Line 85), to test the ability of intracerebral injection of Abeta antibodies to clear amyloid. Because the production of Abeta peptides in the Line 107 model is inducible, whereas production in Line 85 mice is constitutive, we could study the effects of antibody on pre-existing plaques versus continuous plaque formation. In Line 85, injection of antibody resulted in modest but statistically significant reductions in amyloid burden (average, 14%-16%). However, injected antibodies had no effect on amyloid burden in Line 107 under conditions in which the production of Abeta was suppressed, indicating that pre-existing plaques are not rapidly cleared. These results indicate that intracerebral injection of Abeta antibodies produces modest reductions in amyloid deposition in these two models and that the mechanism may involve prevention of amyloid formation rather than clearance of pre-existing plaques.
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123
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Cruz L, Urbanc B, Inglis A, Rosene DL, Stanley HE. Generating a model of the three-dimensional spatial distribution of neurons using density maps. Neuroimage 2008; 40:1105-15. [PMID: 18291677 DOI: 10.1016/j.neuroimage.2007.12.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Revised: 12/22/2007] [Accepted: 12/27/2007] [Indexed: 11/27/2022] Open
Abstract
Microcolumns are a vertical arrangement of neocortical neurons that may constitute a fundamental computational ensemble but have been difficult to study morphologically because of the challenges of determining the three-dimensional (3D) spatial arrangements of individual neurons in the ensemble. Previously, a statistical density map method was developed to characterize microcolumns using two-dimensional (2D) coordinates of neurons from thin tissue sections. Here we extend this approach to derive the relationship between these 2D density maps and the actual 3D properties of microcolumns by creating a theoretical 3D model of cortical neurons. In seven steps, we transform a 3D initial arrangement of neurons from a crystalline lattice, with distances and neuron numbers approximating the idealized cortical microcolumn as assayed by our 2D density map analysis, into a model whose neuronal locations represent a plausible 3D arrangement of neurons in the brain. Because we constrain the transformations on the 3D model by the 2D density map properties, the transformed 3D model will exhibit properties that are consistent with experimental findings regarding microcolumnar anatomy in the brain. Moreover, because our methodology only requires the x,y locations of neurons from thin sections, it is readily accessible to any set of input data regardless of preparation or staining, from human or animals. By generating 3D model neuronal arrangements and comparing between control, aged, and diseased brain, our method can be used to test hypotheses about the effects of neurological diseases as well as normal aging on the 3D structure of microcolumns in the brain.
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Affiliation(s)
- Luis Cruz
- Center for Polymer Studies and Department of Physics, Boston University, Boston, MA 02215, USA.
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124
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Ciccocioppo F, Lanuti P, Marchisio M, Gambi F, Santavenere E, Pierdomenico L, Bascelli A, Velluto L, Gambi D, Miscia S. Expression and Phosphorylation of Protein Kinase C Isoforms in Aβ1–42 Activated T Lymphocytes from Alzheimer's Disease. Int J Immunopathol Pharmacol 2008; 21:23-33. [DOI: 10.1177/039463200802100104] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The protein kinase C (PKC) family of enzymes is a regulator of transmembrane signal transduction. There is evidence demonstrating altered activity of some PKC isoforms (PKC-α, PKC-δ and PKC-ζ) in the neurons of brains of Alzheimer's Disease (AD) sufferers, but little is known about their involvement in the intracellular machinery of amyloid β protein-reactive T lymphocytes in AD. By applying a modified “split-well culture system” for Aβ1–42 reactivity, we carried out flow cytometry analysis and biochemical investigations on the possible involvement of PKC-α, PKC-δ and PKC-ζ in the signalling system activated in Aβ-reactive T cells purified from peripheral blood mononucleate cells (PBMC) from healthy subjects and patients with AD. Flow cytometry analysis of Aβ1–42 activated T lymphocytes in the majority of AD patients highlighted a distinct cellular cluster highly expressing phospho-PKC-δ (P-PKC-δ), while most full-blown AD patients highly expressed two distinct P-PKC-δ and phospho-PKC-ζ (P-PKC-ζ) bright sub-populations. The same investigation performed in freshly purified peripheral T lymphocytes, did not highlight any subpopulation, suggesting that the detection of P-PKC-δ and P-PKC-ζ bright subpopulations is specifically linked to Aβ1–42 activated T lymphocytes. The data presented here, therefore, suggest possible novel hallmarks to discriminate between healthy elderly subjects and beginning or full-blown Alzheimer's Disease patients.
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Affiliation(s)
- F. Ciccocioppo
- Cell Signalling Unit, Department of Biomorphology, “G d'Annunzio” University of Chieti-Pescara, Chieti
- Center for Ageing Sciences (Ce.S.I.), “Università G. d'Annunzio” Foundation, Chieti
| | - P. Lanuti
- Cell Signalling Unit, Department of Biomorphology, “G d'Annunzio” University of Chieti-Pescara, Chieti
- Center for Ageing Sciences (Ce.S.I.), “Università G. d'Annunzio” Foundation, Chieti
| | - M. Marchisio
- Cell Signalling Unit, Department of Biomorphology, “G d'Annunzio” University of Chieti-Pescara, Chieti
- Center for Ageing Sciences (Ce.S.I.), “Università G. d'Annunzio” Foundation, Chieti
| | - F. Gambi
- Department of Oncology and Neuroscience, “G. d'Annunzio” University of Chieti-Pescara, Chieti, Italy
| | - E. Santavenere
- Cell Signalling Unit, Department of Biomorphology, “G d'Annunzio” University of Chieti-Pescara, Chieti
| | - L. Pierdomenico
- Cell Signalling Unit, Department of Biomorphology, “G d'Annunzio” University of Chieti-Pescara, Chieti
- Center for Ageing Sciences (Ce.S.I.), “Università G. d'Annunzio” Foundation, Chieti
| | - A. Bascelli
- Cell Signalling Unit, Department of Biomorphology, “G d'Annunzio” University of Chieti-Pescara, Chieti
- Center for Ageing Sciences (Ce.S.I.), “Università G. d'Annunzio” Foundation, Chieti
| | - L. Velluto
- Center for Ageing Sciences (Ce.S.I.), “Università G. d'Annunzio” Foundation, Chieti
- Department of Oncology and Neuroscience, “G. d'Annunzio” University of Chieti-Pescara, Chieti, Italy
| | - D. Gambi
- Center for Ageing Sciences (Ce.S.I.), “Università G. d'Annunzio” Foundation, Chieti
- Department of Oncology and Neuroscience, “G. d'Annunzio” University of Chieti-Pescara, Chieti, Italy
| | - S. Miscia
- Cell Signalling Unit, Department of Biomorphology, “G d'Annunzio” University of Chieti-Pescara, Chieti
- Center for Ageing Sciences (Ce.S.I.), “Università G. d'Annunzio” Foundation, Chieti
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125
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Li G, Jack CR, Yang XF, Yang ES. Diet supplement CoQ10 delays brain atrophy in aged transgenic mice with mutations in the amyloid precursor protein: an in vivo volume MRI study. Biofactors 2008; 32:169-78. [PMID: 19096113 DOI: 10.1002/biof.5520320120] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We tested the hypotheses that supplemental intake of the diet supplement Coenzyme Q10 (CoQ10) could delay brain atrophy in double transgenic amyloid precursor protein (APP) / presenilin 1 (PS1), single transgenic APP and PS1 as well as wild type mice by volume MR image in vivo. One hundred and twelve mice (28 APP/PS1, 28 APP, 28 PS1 and 28 wild types) were studied. Half of each genotype group (n = 14 per group) was treated with CoQ10 2400 mg/kg/day, and the other half with placebo for 60 days. Magnetic resonance (MR) images were used to obtain the volumes of the hemispheres and hippocampi. APP / PS1, APP, PS1 and wild type mice treated with CoQ10 exhibited significantly less atrophy in hemisphere and hippocampus than those receiving placebo. The neuro-protective effect of the CoQ10 on hemispheric volume, and hippocampal volume was related to genotype; greater in APP/PS1 than APP and PS1 mice and less in wild type mice. Our result indicated that CoQ10 may have therapeutic potential in the prevention and treatment of MCI and AD.
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Affiliation(s)
- Geng Li
- Hong Kong Applied Science and Technology Research Institute Company Limited, Hong Kong, HKSAR, China.
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126
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Duyckaerts C, Potier MC, Delatour B. Alzheimer disease models and human neuropathology: similarities and differences. Acta Neuropathol 2008; 115:5-38. [PMID: 18038275 PMCID: PMC2100431 DOI: 10.1007/s00401-007-0312-8] [Citation(s) in RCA: 276] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2007] [Revised: 10/13/2007] [Accepted: 10/14/2007] [Indexed: 12/02/2022]
Abstract
Animal models aim to replicate the symptoms, the lesions or the cause(s) of Alzheimer disease. Numerous mouse transgenic lines have now succeeded in partially reproducing its lesions: the extracellular deposits of Abeta peptide and the intracellular accumulation of tau protein. Mutated human APP transgenes result in the deposition of Abeta peptide, similar but not identical to the Abeta peptide of human senile plaque. Amyloid angiopathy is common. Besides the deposition of Abeta, axon dystrophy and alteration of dendrites have been observed. All of the mutations cause an increase in Abeta 42 levels, except for the Arctic mutation, which alters the Abeta sequence itself. Overexpressing wild-type APP alone (as in the murine models of human trisomy 21) causes no Abeta deposition in most mouse lines. Doubly (APP x mutated PS1) transgenic mice develop the lesions earlier. Transgenic mice in which BACE1 has been knocked out or overexpressed have been produced, as well as lines with altered expression of neprilysin, the main degrading enzyme of Abeta. The APP transgenic mice have raised new questions concerning the mechanisms of neuronal loss, the accumulation of Abeta in the cell body of the neurons, inflammation and gliosis, and the dendritic alterations. They have allowed some insight to be gained into the kinetics of the changes. The connection between the symptoms, the lesions and the increase in Abeta oligomers has been found to be difficult to unravel. Neurofibrillary tangles are only found in mouse lines that overexpress mutated tau or human tau on a murine tau -/- background. A triply transgenic model (mutated APP, PS1 and tau) recapitulates the alterations seen in AD but its physiological relevance may be discussed. A number of modulators of Abeta or of tau accumulation have been tested. A transgenic model may be analyzed at three levels at least (symptoms, lesions, cause of the disease), and a reading key is proposed to summarize this analysis.
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Affiliation(s)
- Charles Duyckaerts
- Laboratoire de Neuropathologie Raymond Escourolle, Hôpital de La Salpêtrière, 47 Boulevard de l'Hôpital, 75651, Paris Cedex 13, France.
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127
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Rak M, Del Bigio MR, Mai S, Westaway D, Gough K. Dense-core and diffuse Abeta plaques in TgCRND8 mice studied with synchrotron FTIR microspectroscopy. Biopolymers 2007; 87:207-17. [PMID: 17680701 DOI: 10.1002/bip.20820] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Plaques composed of the Abeta peptide are the main pathological feature of Alzheimer's disease. Dense-core plaques are fibrillar deposits of Abeta, showing all the classical properties of amyloid including beta-sheet secondary structure, while diffuse plaques are amorphous deposits. We studied both plaque types, using synchrotron infrared (IR) microspectroscopy, a technique that allows the chemical composition and average protein secondary structure to be investigated in situ. We examined plaques in hippocampal, cortical and caudal tissue from 5- to 21-month-old TgCRND8 mice, a transgenic model expressing doubly mutant amyloid precursor protein, and displaying impaired hippocampal function and robust pathology from an early age. Spectral analysis confirmed that the congophilic plaque cores were composed of protein in a beta-sheet conformation. The amide I maximum of plaque cores was at 1623 cm(-1), and unlike for in vitro Abeta fibrils, the high-frequency (1680-1690 cm(-1)) component attributed to antiparallel beta-sheet was not observed. A significant elevation in phospholipids was found around dense-core plaques in TgCRND8 mice ranging in age from 5 to 21 months. In contrast, diffuse plaques were not associated with IR detectable changes in protein secondary structure or relative concentrations of any other tissue components.
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Affiliation(s)
- Margaret Rak
- Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
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128
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Lesné S, Kotilinek L, Ashe KH. Plaque-bearing mice with reduced levels of oligomeric amyloid-beta assemblies have intact memory function. Neuroscience 2007; 151:745-9. [PMID: 18155846 DOI: 10.1016/j.neuroscience.2007.10.054] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2007] [Revised: 10/19/2007] [Accepted: 11/27/2007] [Indexed: 11/17/2022]
Abstract
The amyloid-beta (Abeta) protein exists in the aging mammalian brain in diverse assembly states, including amyloid plaques and soluble Abeta oligomers. Both forms of Abeta have been shown to impair neuronal function, but their precise roles in Alzheimer's disease (AD) -associated memory loss remain unclear. Both types of Abeta are usually present at the same time in the brain, which has made it difficult to evaluate the effects of plaques and oligomers individually on memory function. Recently, a particular oligomeric Abeta assembly, Abeta 56, was found to impair memory function in the absence of amyloid plaques. Until now it has not been possible to determine the effects of plaques, in the absence of Abeta oligomers, on memory function. We have identified Tg2576 mice with plaques but markedly reduced levels of Abeta oligomers, which enabled us to study the effects of plaques alone on memory function. We found that animals with amyloid plaques have normal memory function throughout an episode of reduced Abeta oligomers, which occurs during a period of accelerated amyloid plaque formation. These observations support the importance of Abeta oligomers in memory loss and indicate that, at least initially, amyloid plaques do not impair memory.
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Affiliation(s)
- S Lesné
- Department of Neurology, MMC 295, 420 Delaware Street Southeast, University of Minnesota, Minneapolis, MN 55455, USA
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129
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The place of choline acetyltransferase activity measurement in the "cholinergic hypothesis" of neurodegenerative diseases. Neurochem Res 2007; 33:318-27. [PMID: 17940885 DOI: 10.1007/s11064-007-9497-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Accepted: 08/29/2007] [Indexed: 01/06/2023]
Abstract
The so-called "cholinergic hypothesis" assumes that degenerative dysfunction of the cholinergic system originating in the basal forebrain and innervating several cortical regions and the hippocampus, is related to memory impairment and neurodegeneration found in several forms of dementia and in brain aging. Biochemical methods measuring the activity of the key enzyme for acetylcholine synthesis, choline acetyltransferase, have been used for many years as a reliable marker of the integrity or the damage of the cholinergic pathways. Stereologic counting of the basal forebrain cholinergic cell bodies, has been additionally used to assess neurodegenerative changes of the forebrain cholinergic system. While initially believed to mark relatively early stages of disease, cholinergic dysfunction is at present considered to occur in advanced dementia of Alzheimer's type, while its involvement in mild and prodromal stages of the disease has been questioned. The issue is relevant to better understand the neuropathological basis of the diseases, but it is also of primary importance for therapy. During the last few years, indeed, cholinergic replacement therapies, mainly based on the use of acetylcholinesterase inhibitors to increase synaptic availability of acetylcholine, have been exploited on the assumption that they could ameliorate the progression of the dementia from its initial stages. In the present paper, we review data from human studies, as well as from animal models of Alzheimer's and Down's diseases, focusing on different ways to evaluate cholinergic dysfunction, also in relation to the time point at which these dysfunctions can be demonstrated, and on some discrepancy arising from the use of different methodological approaches. The reviewed literature, as well as some recent data from our laboratories on a mouse model of Down's syndrome, stress the importance of performing biochemical evaluation of choline acetyltransferase activity to assess cholinergic dysfunction both in humans and in animal models.
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130
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Tenner AJ, Fonseca MI. The Double-Edged Flower: Roles of Complement Protein C1q in Neurodegenerative Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 586:153-76. [PMID: 16893071 DOI: 10.1007/0-387-34134-x_11] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A role for the complement cascade in AD neuropathology was hypothesized over a decade ago, and the results of a significant number of in vitro studies are consistent with the involvement of this pathway in AD pathogenesis (reviewed in). Since C1q is colocalized with thioflavine-positive plaques and the C5b-9 complement membrane attack complex is detected in AD brain at autopsy, it is reasonable to hypothesize that complement activation has a role in the manifestation of AD either by its lytic capacity or as a trigger of glial infiltration and initiation of potentially damaging inflammation. The observed diminished glial activation and reduced loss of neuronal integrity in a murine model overexpressing mutant human APP but lacking the ability to activate the classical complement cascade provide the first direct evidence for a detrimental role of C1q, and presumably activation of the classical complement pathway in an animal model of AD. Research is now focused on generating mouse models that more closely mimic the human disease, so that the role of complement activation and inflammation on the behavioral/learning and memory dysfunction that occurs in this disease can be assessed. In addition, candidate therapies such as targeted inhibition of complement activation will need to be tested in these animal models as a step toward treatment of humans with the disease. However, it is important that the potential for a protective effect of C1q early on in disease progression should not be overlooked. Rather, strategies that enhance or mimic the protective effects of C1q as well as strategies that inhibit the detrimental processes should be fully investigated.
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Affiliation(s)
- Andrea J Tenner
- Department of Molecular Biology, Center for Immunology, University of California, Irvine, CA 92697, USA
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131
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Dong H, Martin MV, Chambers S, Csernansky JG. Spatial relationship between synapse loss and beta-amyloid deposition in Tg2576 mice. J Comp Neurol 2007; 500:311-21. [PMID: 17111375 PMCID: PMC1661843 DOI: 10.1002/cne.21176] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Although there is evidence that beta-amyloid impairs synaptic function, the relationship between beta-amyloid and synapse loss is not well understood. In this study we assessed synapse density within the hippocampus and the entorhinal cortex of Tg2576 mice at 6-18 months of age using stereological methods at both the light and electron microscope levels. Under light microscopy we failed to find overall decreases in the density of synaptophysin-positive boutons in any brain areas selected, but bouton density was significantly decreased within 200 mum of compact beta-amyloid plaques in the outer molecular layer of the dentate gyrus and Layers II and III of the entorhinal cortex at 15-18 months of age in Tg 2576 mice. Under electron microscopy, we found overall decreases in synapse density in the outer molecular layer of the dentate gyrus at both 6-9 and 15-18 months of age, and in Layers II and III of the entorhinal cortex at 15-18 months of age in Tg 2576 mice. However, we did not find overall changes in synapse density in the stratum radiatum of the CA1 subfield. Furthermore, in the two former brain areas we found a correlation between lower synapse density and greater proximity to beta-amyloid plaques. These results provide the first quantitative morphological evidence at the ultrastructure level of a spatial relationship between beta-amyloid plaques and synapse loss within the hippocampus and the entorhinal cortex of Tg2576 mice.
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Affiliation(s)
- Hongxin Dong
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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132
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The amyloid beta ion channel hypothesis of Alzheimer's disease. Neuropsychiatr Dis Treat 2007; 3:597-612. [PMID: 19300589 PMCID: PMC2656296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alzheimer's disease (AD) is a leading cause of chronic dementia in the US. Its incidence is increasing with an attendant increase in associated health care costs. Since its first description in a patient by Dr. Alois Alzheimer over a century ago, a large body of biomedical literature has established a detailed clinical and molecular profile of this disorder. Amyloid beta peptide (Abeta; a 39-42 amino acid molecule) is the major component of senile plaques, the lesions that are one of the pathologic hallmarks of AD (Wong et al 1985). Although many aspects of the biology of amyloid beta have been investigated, several fundamental questions about how this peptide causes AD neuropathology remain unanswered. The key question is: How is Abeta toxic to cerebral neurons? Because plaques are extra-neuronal deposits, it is difficult to imagine a structural basis for their toxicity. As an interesting contrast the other pathognomonic feature of AD, neurofibrillary tangles, are intra-axonal structural anomalies that are composed of the hyperphosphorylated microtubule associated (MAP) protein, tau. This review will assess the current thinking that relates to a recent hypothesis of Abeta toxicity. In 1992, Hardy and Higgins reported findings that suggested a new and intriguing possibility. These authors found that Abeta peptides disrupt Ca(2+) homeostasis in neurons and increase intracellular Ca(2+) [Ca(2+)](i). This was corroborated by Mattson and his colleagues who demonstrated that Abeta exposure to human cortical neurons raised [Ca2(+)](i) (Mattson, Cheng et al 1992); (Hardy and Higgins 1992). Finally, Nelson Arispe's group at the NIH specifically investigated the possibility that Abeta peptides might function like Ca(2+) ion channels (Arispe et al 1993). This and several subsequent studies have laid the foundation for a novel idea: "Abeta peptides are, in part, toxic to neurons because they form aberrant ion channels in neuronal membranes and thereby disrupt neuronal homeostasis". In this review we shall critically examine this theory in light of classic and contemporary literature.
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133
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Garcia-Alloza M, Dodwell SA, Meyer-Luehmann M, Hyman BT, Bacskai BJ. Plaque-derived oxidative stress mediates distorted neurite trajectories in the Alzheimer mouse model. J Neuropathol Exp Neurol 2006; 65:1082-9. [PMID: 17086105 DOI: 10.1097/01.jnen.0000240468.12543.af] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Alzheimer disease (AD) is characterized both by senile plaques and neurodegeneration, although the details of the relationship between the 2 are not well understood. We postulated that oxidative stress resulting from senile plaques may mediate plaques' effects on local neuronal processes. Using multiphoton microscopy, we directly demonstrate the generation of reactive oxygen species by senile plaques. After screening of several natural antioxidants ex vivo, we assessed in vivo the effect of 2 orally administered antioxidants in APPswe/PS1d9 transgenic mice. Both Ginkgo biloba extract and vitamin E reduced the oxidative stress resulting from senile plaques in vivo as monitored with intracranial imaging. Both treatments also lead to a progressive reversal of the structural changes in dystrophic neurites associated with senile plaques. These results suggest a causal relationship between plaque-associated oxidative stress and neuritic alterations and demonstrate for the first time that the focal neurotoxicity associated with the senile plaques of AD is partially reversible with antioxidant therapies. The quantitative ex vivo screen combined with in vivo monitoring of efficacy should lead to more effective clinical therapies for the prevention of oxidative stress and neurotoxicity in AD.
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Affiliation(s)
- Monica Garcia-Alloza
- Department of Neurology/Alzheimer's Disease Research Laboratory, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
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134
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Ohno M, Cole SL, Yasvoina M, Zhao J, Citron M, Berry R, Disterhoft JF, Vassar R. BACE1 gene deletion prevents neuron loss and memory deficits in 5XFAD APP/PS1 transgenic mice. Neurobiol Dis 2006; 26:134-45. [PMID: 17258906 PMCID: PMC1876698 DOI: 10.1016/j.nbd.2006.12.008] [Citation(s) in RCA: 228] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 11/29/2006] [Accepted: 12/06/2006] [Indexed: 10/23/2022] Open
Abstract
Evidence suggests that beta-amyloid (Abeta) peptide triggers a pathogenic cascade leading to neuronal loss in Alzheimer's disease (AD). However, the causal link between Abeta and neuron death in vivo remains unclear since most animal models fail to recapitulate the dramatic cell loss observed in AD. We have recently developed transgenic mice that overexpress human APP and PS1 with five familial AD mutations (5XFAD mice) and exhibit robust neuron death. Here, we demonstrate that genetic deletion of the beta-secretase (BACE1) not only abrogates Abeta generation and blocks amyloid deposition but also prevents neuron loss found in the cerebral cortex and subiculum, brain regions manifesting the most severe amyloidosis in 5XFAD mice. Importantly, BACE1 gene deletion also rescues memory deficits in 5XFAD mice. Our findings provide strong evidence that Abeta ultimately is responsible for neuron death in AD and validate the therapeutic potential of BACE1-inhibiting approaches for the treatment of AD.
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Affiliation(s)
- Masuo Ohno
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611-3008, USA.
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135
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Uversky VN, Kabanov AV, Lyubchenko YL. Nanotools for megaproblems: probing protein misfolding diseases using nanomedicine modus operandi. J Proteome Res 2006; 5:2505-22. [PMID: 17022621 PMCID: PMC1880889 DOI: 10.1021/pr0603349] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Misfolding and self-assembly of proteins in nanoaggregates of different sizes and morphologies (nanoensembles, primary nanofilaments, nanorings, filaments, protofibrils, fibrils, etc.) is a common theme unifying a number of human pathologies termed protein misfolding diseases. Recent studies highlight increasing recognition of the public health importance of protein misfolding diseases, including various neurodegenerative disorders and amyloidoses. It is understood now that the first essential elements in the vast majority of neurodegenerative processes are misfolded and aggregated proteins. Altogether, the accumulation of abnormal protein nanoensembles exerts toxicity by disrupting intracellular transport, overwhelming protein degradation pathways, and/or disturbing vital cell functions. In addition, the formation of inclusion bodies is known to represent a major problem in the production of recombinant therapeutic proteins. Formulation of these therapeutic proteins into delivery systems and their in vivo delivery are often complicated by protein association. Thus, protein folding abnormalities and subsequent events underlie a multitude of human pathologies and difficulties with protein therapeutic applications. The field of medicine therefore can be greatly advanced by establishing a fundamental understanding of key factors leading to misfolding and self-assembly responsible for various protein folding pathologies. This article overviews protein misfolding diseases and outlines some novel and advanced nanotechnologies, including nanoimaging techniques, nanotoolboxes and nanocontainers, complemented by appropriate ensemble techniques, all focused on the ultimate goal to establish etiology and to diagnose, prevent, and cure these devastating disorders.
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Affiliation(s)
- Vladimir N Uversky
- Center for Computational Biology and Bioinformatics, Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
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136
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Abstract
Two-photon microscopy (TPM) has become an increasingly important tool for imaging the structure and function of brain cells in living animals. TPM imaging studies of neuronal structures over intervals ranging from seconds to years have begun to provide important insights into the structural plasticity of synapses and the modulating effects of experience in the intact brain. TPM has also started to reveal how neuronal connections are altered in animal models of neurodegeneration, acute brain injury, and cerebrovascular disease. Here, we review some of these studies with special emphasis on the degree of structural dynamism of postsynaptic dendritic spines in the adult mouse brain as well as synaptic pathology in mouse models of Alzheimer's disease and cerebral ischemia. We also discuss technical considerations that are critical for the acquisition and interpretation of data from TPM in vivo.
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Affiliation(s)
- Jaime Grutzendler
- />Northwestern University, 303 East Chicago Avenue, Ward Building 10-132, 60611 Chicago, IL
| | - Wen-Biao Gan
- />Skirball Institute of Biomolecular Medicine, Department of Physiology and Neuroscience, New York University School of Medicine, 540 First Avenue, 10016 New York, NY
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137
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Oakley H, Cole SL, Logan S, Maus E, Shao P, Craft J, Guillozet-Bongaarts A, Ohno M, Disterhoft J, Van Eldik L, Berry R, Vassar R. Intraneuronal beta-amyloid aggregates, neurodegeneration, and neuron loss in transgenic mice with five familial Alzheimer's disease mutations: potential factors in amyloid plaque formation. J Neurosci 2006; 26:10129-40. [PMID: 17021169 PMCID: PMC6674618 DOI: 10.1523/jneurosci.1202-06.2006] [Citation(s) in RCA: 2297] [Impact Index Per Article: 127.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mutations in the genes for amyloid precursor protein (APP) and presenilins (PS1, PS2) increase production of beta-amyloid 42 (Abeta42) and cause familial Alzheimer's disease (FAD). Transgenic mice that express FAD mutant APP and PS1 overproduce Abeta42 and exhibit amyloid plaque pathology similar to that found in AD, but most transgenic models develop plaques slowly. To accelerate plaque development and investigate the effects of very high cerebral Abeta42 levels, we generated APP/PS1 double transgenic mice that coexpress five FAD mutations (5XFAD mice) and additively increase Abeta42 production. 5XFAD mice generate Abeta42 almost exclusively and rapidly accumulate massive cerebral Abeta42 levels. Amyloid deposition (and gliosis) begins at 2 months and reaches a very large burden, especially in subiculum and deep cortical layers. Intraneuronal Abeta42 accumulates in 5XFAD brain starting at 1.5 months of age (before plaques form), is aggregated (as determined by thioflavin S staining), and occurs within neuron soma and neurites. Some amyloid deposits originate within morphologically abnormal neuron soma that contain intraneuronal Abeta. Synaptic markers synaptophysin, syntaxin, and postsynaptic density-95 decrease with age in 5XFAD brain, and large pyramidal neurons in cortical layer 5 and subiculum are lost. In addition, levels of the activation subunit of cyclin-dependent kinase 5, p25, are elevated significantly at 9 months in 5XFAD brain, although an upward trend is observed by 3 months of age, before significant neurodegeneration or neuron loss. Finally, 5XFAD mice have impaired memory in the Y-maze. Thus, 5XFAD mice rapidly recapitulate major features of AD amyloid pathology and may be useful models of intraneuronal Abeta42-induced neurodegeneration and amyloid plaque formation.
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Affiliation(s)
| | | | | | - Erika Maus
- Departments of Cell and Molecular Biology and
| | - Pei Shao
- Departments of Cell and Molecular Biology and
| | | | | | - Masuo Ohno
- Physiology, The Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - John Disterhoft
- Physiology, The Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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138
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Lyubchenko YL, Sherman S, Shlyakhtenko LS, Uversky VN. Nanoimaging for protein misfolding and related diseases. J Cell Biochem 2006; 99:52-70. [PMID: 16823798 PMCID: PMC1557678 DOI: 10.1002/jcb.20989] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Misfolding and aggregation of proteins is a common thread linking a number of important human health problems. The misfolded and aggregated proteins are inducers of cellular stress and activators of immunity in neurodegenerative diseases. They might possess clear cytotoxic properties, being responsible for the dysfunction and loss of cells in the affected organs. Despite the crucial importance of protein misfolding and abnormal interactions, very little is currently known about the molecular mechanism underlying these processes. Factors that lead to protein misfolding and aggregation in vitro are poorly understood, not to mention the complexities involved in the formation of protein nanoparticles with different morphologies (e.g., the nanopores) in vivo. A better understanding of the molecular mechanisms of misfolding and aggregation might facilitate development of the rational approaches to prevent pathologies mediated by protein misfolding. The conventional tools currently available to researchers can only provide an averaged picture of a living system, whereas much of the subtle or short-lived information is lost. We believe that the existing and emerging nanotools might help solving these problems by opening the entirely novel pathways for the development of early diagnostic and therapeutic approaches. This article summarizes recent advances of the nanoscience in detection and characterization of misfolded protein conformations. Based on these findings, we outline our view on the nanoscience development towards identification intracellular nanomachines and/or multicomponent complexes critically involved in protein misfolding.
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Affiliation(s)
- Yuri L Lyubchenko
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska 68198-6025, USA.
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139
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Radde R, Bolmont T, Kaeser SA, Coomaraswamy J, Lindau D, Stoltze L, Calhoun ME, Jäggi F, Wolburg H, Gengler S, Haass C, Ghetti B, Czech C, Hölscher C, Mathews PM, Jucker M. Abeta42-driven cerebral amyloidosis in transgenic mice reveals early and robust pathology. EMBO Rep 2006; 7:940-6. [PMID: 16906128 PMCID: PMC1559665 DOI: 10.1038/sj.embor.7400784] [Citation(s) in RCA: 708] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Revised: 07/11/2006] [Accepted: 07/17/2006] [Indexed: 02/08/2023] Open
Abstract
We have generated a novel transgenic mouse model on a C57BL/6J genetic background that coexpresses KM670/671NL mutated amyloid precursor protein and L166P mutated presenilin 1 under the control of a neuron-specific Thy1 promoter element (APPPS1 mice). Cerebral amyloidosis starts at 6-8 weeks and the ratio of human amyloid (A)beta42 to Abeta40 is 1.5 and 5 in pre-depositing and amyloid-depositing mice, respectively. Consistent with this ratio, extensive congophilic parenchymal amyloid but minimal amyloid angiopathy is observed. Amyloid-associated pathologies include dystrophic synaptic boutons, hyperphosphorylated tau-positive neuritic structures and robust gliosis, with neocortical microglia number increasing threefold from 1 to 8 months of age. Global neocortical neuron loss is not apparent up to 8 months of age, but local neuron loss in the dentate gyrus is observed. Because of the early onset of amyloid lesions, the defined genetic background of the model and the facile breeding characteristics, APPPS1 mice are well suited for studying therapeutic strategies and the pathomechanism of amyloidosis by cross-breeding to other genetically engineered mouse models.
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Affiliation(s)
- Rebecca Radde
- Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, Otfried-Müller Strasse 27, D-72076 Tübingen, Germany
| | - Tristan Bolmont
- Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, Otfried-Müller Strasse 27, D-72076 Tübingen, Germany
| | - Stephan A Kaeser
- Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, Otfried-Müller Strasse 27, D-72076 Tübingen, Germany
| | - Janaky Coomaraswamy
- Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, Otfried-Müller Strasse 27, D-72076 Tübingen, Germany
| | - Dennis Lindau
- Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, Otfried-Müller Strasse 27, D-72076 Tübingen, Germany
| | - Lars Stoltze
- Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, Otfried-Müller Strasse 27, D-72076 Tübingen, Germany
| | - Michael E Calhoun
- Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, Otfried-Müller Strasse 27, D-72076 Tübingen, Germany
| | - Fabienne Jäggi
- Department of Neuropathology, Institute of Pathology, University of Basel, CH-4003 Basel, Switzerland
| | - Hartwig Wolburg
- Department of Pathology, University of Tübingen, D-72076 Tübingen, Germany
| | - Simon Gengler
- School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, UK
| | - Christian Haass
- Department of Biochemistry, Adolf Butenandt Institute, D-80336 Munich, Germany
| | - Bernardino Ghetti
- Department of Pathology and Laboratory Medicine, Indiana School of Medicine, Indianapolis, Indiana 46202, USA
| | - Christian Czech
- Department of Pharma Research Biology Discovery, F. Hoffmann-LaRoche Ltd, CH-4070 Basel, Switzerland
| | - Christian Hölscher
- School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, UK
| | - Paul M Mathews
- Nathan Kline Institute, New York University School of Medicine, Orangeburg, New York 10962, USA
| | - Mathias Jucker
- Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, Otfried-Müller Strasse 27, D-72076 Tübingen, Germany
- Department of Neuropathology, Institute of Pathology, University of Basel, CH-4003 Basel, Switzerland
- Tel: +49 7071 29 86863; Fax: +49 7071 29 4521; E-mail:
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140
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Lee HG, Zhu X, Takeda A, Perry G, Smith MA. Emerging evidence for the neuroprotective role of α-synuclein. Exp Neurol 2006; 200:1-7. [PMID: 16780837 DOI: 10.1016/j.expneurol.2006.04.024] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Revised: 04/26/2006] [Accepted: 04/28/2006] [Indexed: 12/21/2022]
Affiliation(s)
- Hyoung-gon Lee
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
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141
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Matsui T, Ramasamy K, Ingelsson M, Fukumoto H, Conrad C, Frosch MP, Irizarry MC, Yuan J, Hyman BT. Coordinated Expression of Caspase 8, 3 and 7 mRNA in Temporal Cortex of Alzheimer Disease: Relationship to Formic Acid Extractable Aβ42 Levels. J Neuropathol Exp Neurol 2006; 65:508-15. [PMID: 16772874 DOI: 10.1097/01.jnen.0000229238.05748.12] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Recent studies support the hypothesis that Alzheimer disease (AD)-associated amyloid-beta protein (Abeta) may induce apoptosis mediated by a caspase cascade. To assess whether mRNA levels of caspase-3, 7, 8 and 9 change in AD brain, and whether these changes correlate with neurofibrillary tangles, Abeta40 or Abeta42 protein levels or senile plaques, 25 AD and 21 non-demented control brains were examined. Elevated mRNA levels of caspases-7 and 8 measured by a quantitative PCR method were observed in the AD temporal neocortex as compared to the control brains. No significant differences were noticed in levels of caspases-3 or 9 between AD and control brains. Multiple regression analysis demonstrated that, within subjects, the mRNA levels of caspase-8 strongly correlated with both caspse-3 and caspase-7 independently of postmortem interval. Further, there was a strong positive correlation of caspase-8 levels with formic acid extractable Abeta42 levels. Our results suggest that the transcriptional activation of key components of the apoptotic cascade correlates with accumulation of Abeta 42. Thus, a principal caspase pathway from caspase-8 to caspase-3 and/or 7 may contribute to neuron loss in AD brain.
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Affiliation(s)
- Toshifumi Matsui
- Alzheimer Research Unit, Mass General Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
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142
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Qin S, Colin C, Hinners I, Gervais A, Cheret C, Mallat M. System Xc- and apolipoprotein E expressed by microglia have opposite effects on the neurotoxicity of amyloid-beta peptide 1-40. J Neurosci 2006; 26:3345-56. [PMID: 16554485 PMCID: PMC6674113 DOI: 10.1523/jneurosci.5186-05.2006] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Because senile plaques in Alzheimer's disease (AD) contain reactive microglia in addition to potentially neurotoxic aggregates of amyloid-beta (Abeta), we examined the influence of microglia on the viability of rodent neurons in culture exposed to aggregated Abeta 1-40. Microglia enhanced the toxicity of Abeta by releasing glutamate through the cystine-glutamate antiporter system Xc-. This may be relevant to Abeta toxicity in AD, because the system Xc(-)-specific xCT gene is expressed not only in cultured microglia but also in reactive microglia within or surrounding amyloid plaques in transgenic mice expressing mutant human amyloid precursor protein or in wild-type mice injected with Abeta. Inhibition of NMDA receptors or system Xc- prevented the microglia-enhanced neurotoxicity of Abeta but also unmasked a neuroprotective effect of microglia mediated by microglial secretion of apolipoprotein E (apoE) in the culture medium. Immunodepletion of apoE or targeted inactivation of the apoE gene in microglia abrogated neuroprotection by microglial conditioned medium, whereas supplementation by human apoE isoforms restored protection, which was potentiated by the presence of microglia-derived cofactors. These results suggest that inhibition of microglial system Xc- might be of therapeutic value in the treatment of AD. Its inhibition not only prevents glutamate excitotoxicity but also facilitates neuroprotection by apoE.
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143
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Wearne SL, Rodriguez A, Ehlenberger DB, Rocher AB, Henderson SC, Hof PR. New techniques for imaging, digitization and analysis of three-dimensional neural morphology on multiple scales. Neuroscience 2006; 136:661-80. [PMID: 16344143 DOI: 10.1016/j.neuroscience.2005.05.053] [Citation(s) in RCA: 240] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 05/17/2005] [Accepted: 05/19/2005] [Indexed: 01/15/2023]
Abstract
Cognitive impairment in normal aging and neurodegenerative diseases is accompanied by altered morphologies on multiple scales. Understanding of the role of these structural changes in producing functional deficits in brain aging and neuropsychiatric disorders requires accurate three-dimensional representations of neuronal morphology, and realistic biophysical modeling that can directly relate structural changes to altered neuronal firing patterns. To date however, tools capable of resolving, digitizing and analyzing neuronal morphology on both local and global scales, and with sufficient throughput and automation, have been lacking. The precision of existing image analysis-based morphometric tools is restricted at the finest scales, where resolution of fine dendritic features and spine geometry is limited by the skeletonization methods used, and by quantization errors arising from insufficient imaging resolution. We are developing techniques for imaging, reconstruction and analysis of neuronal morphology that capture both local and global structural variation. To minimize quantization error and evaluate more precisely the fine geometry of dendrites and spines, we introduce a new shape analysis technique, the Rayburst sampling algorithm that uses the original grayscale data rather than the segmented images for precise, continuous radius estimation, and multidirectional radius sampling to represent non-circular branch cross-sections and anisotropic structures such as dendritic spine heads, with greater accuracy. We apply the Rayburst technique to 3D neuronal shape analysis at different scales. We reconstruct and digitize entire neurons from stacks of laser-scanning microscopy images, as well as globally complex structures such as multineuron networks and microvascular networks. We also introduce imaging techniques necessary to recover detailed information on three-dimensional mass distribution and surface roughness of amyloid beta plaques from human Alzheimer's disease patients and from the Tg2576 mouse that expresses the "Swedish" mutation of the amyloid precursor protein. By providing true three-dimensional morphometry of complex histologic structures on multiple scales, the tools described in this report will enable multiscale biophysical modeling studies capable of testing potential mechanisms by which altered dendritic structure, spine geometry and network branching patterns that occur in normal aging and in many brain disorders, determine deficits of functions such as working memory and cognition.
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MESH Headings
- Aged
- Aged, 80 and over
- Alzheimer Disease/genetics
- Alzheimer Disease/pathology
- Animals
- Cell Size
- Diagnostic Imaging
- Disease Models, Animal
- Female
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Hippocampus/pathology
- Humans
- Imaging, Three-Dimensional
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Microscopy, Confocal/methods
- Microscopy, Electron, Scanning/methods
- Models, Anatomic
- Neurons/metabolism
- Neurons/pathology
- Neurons/ultrastructure
- Plaque, Amyloid/ultrastructure
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Affiliation(s)
- S L Wearne
- Computational Neurobiology and Imaging Center, Mount Sinai School of Medicine, New York, NY 10029-6574, USA.
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144
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Ramsden M, Kotilinek L, Forster C, Paulson J, McGowan E, SantaCruz K, Guimaraes A, Yue M, Lewis J, Carlson G, Hutton M, Ashe KH. Age-dependent neurofibrillary tangle formation, neuron loss, and memory impairment in a mouse model of human tauopathy (P301L). J Neurosci 2006; 25:10637-47. [PMID: 16291936 PMCID: PMC6725849 DOI: 10.1523/jneurosci.3279-05.2005] [Citation(s) in RCA: 482] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Here, we describe the generation of a novel transgenic mouse model of human tauopathy. The rTg(tau(P301L))4510 mouse expresses the P301L mutation in tau (4R0N) associated with frontotemporal dementia and parkinsonism linked to chromosome 17. Transgene expression was driven by a forebrain-specific Ca(2+) calmodulin kinase II promoter system resulting in high levels of expression in the hippocampus and neocortex. Importantly, transgene expression in this model is induced via the tetracycline-operon responsive element and is suppressed after treatment with doxycycline. Continued transgene expression in rTg(tau(P301L))4510 mice results in age-dependent development of many salient characteristics of hereditary human dementia. From an early age, immunohistochemical studies demonstrated abnormal biochemical processing of tau and the presence of pathological conformation- and phosphorylation-dependent epitopes. Neurofibrillary tangle (NFT) pathology was first observed in the neocortex and progressed into the hippocampus and limbic structures with increasing age. Consistent with the formation of NFTs, immunoblots indicated an age-dependent transition of accumulating tau species from Sarkosyl soluble 55 kDa to insoluble hyperphosphorylated 64 kDa. Ultrastructural analysis revealed the presence of straight tau filaments. Furthermore, the effects of tau(P301L) expression on spatial reference memory were longitudinally tested using the Morris water maze. Compared with nontransgenic age-matched control littermates, rTg(tau(P301L))4510 mice developed significant cognitive impairments from 4 months of age. Memory deficits were accompanied by gross forebrain atrophy and a prominent loss of neurons, most strikingly in hippocampal subdivision CA1. Collectively, these data describe a novel transgenic mouse that closely mimics human tauopathy and may represent an important model for the future study of tau-related neurodegenerative disease.
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Affiliation(s)
- Martin Ramsden
- Department of Neurology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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145
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Boldron C, Van der Auwera I, Deraeve C, Gornitzka H, Wera S, Pitié M, Van Leuven F, Meunier B. Preparation of cyclo-phen-type ligands: chelators of metal ions as potential therapeutic agents in the treatment of neurodegenerative diseases. Chembiochem 2006; 6:1976-80. [PMID: 16208731 DOI: 10.1002/cbic.200500220] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Christophe Boldron
- Laboratoire de Chimie de Coordination du CNRS, 205 route de Narbonne, 31077 Toulouse Cedex 4, France
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146
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Abstract
As the scope of the problem of Alzheimer's disease (AD) grows due to an aging population, research into the devastating condition has taken on added urgency. Rare inherited forms of AD provide insight into the molecular pathways leading to degeneration and have made possible the development of transgenic animal models. Several of these models are based on the overexpression of amyloid precursor protein (APP), presenilins, or tau to cause production and accumulation of amyloid-beta into plaques or hyperphosphorylated tau into neurofibrillary tangles. Producing these characteristic neuropathological lesions in animals causes progressive neurodegeneration and in some cases similar behavioral disruptions to those seen in AD patients. Knockout models of proteins involved in AD have also been generated to explore the native functions of these genes and examine whether pathogenesis is due to loss of function or toxic gain of function in these systems. Although none of the transgenic lines models the human condition exactly, the ability to study similar pathological processes in living animals have provided numerous insights into disease mechanisms and opportunities to test therapeutic agents. This chapter reviews animal models of AD and their contributions to developing therapeutic approaches for AD.
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Affiliation(s)
- Tara L Spires
- Harvard Medical School, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
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147
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He Y, Sun SH, Chen RW, Guo YJ, He XW, Huang L, Chen ZH, Shi K, Zhu WJ. Effects of Epitopes Combination and Adjuvants on Immune Responses to Anti-Alzheimer Disease DNA Vaccines in Mice. Alzheimer Dis Assoc Disord 2005; 19:171-7. [PMID: 16327342 DOI: 10.1097/01.wad.0000189031.58450.5a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Alzheimer disease (AD) is a neurodegenerative disorder characterized by neuropathological hallmarks including deposits of the beta-amyloid peptide (AssP). Studies have shown that immunization with Abeta42 peptide reduces both the spatial memory impairments and Alzheimer disease-like neuropathologic changes in Alzheimer disease transgenic mice, but can cause side effect of a cell-mediated autoimmune meningoencephalitis. Recently, some studies showed that DNA vaccination could be used to generate an antibody response to Abeta without the adverse cell-mediated immune effect. In the current study, we generate four DNA vaccine plasmids (pV-GE1, pV-GE2, pV-GE3, and pV-GE4) against Alzheimer disease by separately fusing Abeta epitope sequences (coding for EFGH, DAEFGH, EFGH+EFGH, and EFGH+DAEFGH) with IgG heavy chain coding region of mouse. Meanwhile, the full-length gene Abeta encoding plasmid (pV-Abeta), empty vector (pVAX) and synthetic AssP were also included as control. The sera of BALB/c mice immunized via intramuscular with plasmids and peptide were tested by indirect ELISA for auto-AssP immunoreactivity. The results showed that all the DNA vaccine plasmids induced AssP-specific antibodies; moreover pV-GE2 and pV-Abeta constructs elicited higher antibody titers than other constructs (P < 0.05). To further enhance the immune response, GM-CSF encoding plasmid (pGM-CSF) and purified BCG-DNA were used as molecular adjuvants. BCG-DNA could enhance humoral and cellular immune responses simultaneously and did not alter the phenotype of the immune responses, whereas pGM-CSF showed no obvious effect on immune response. These results suggest that this immunization strategy of using Abeta epitope encoding plasmid plus BCG-DNA adjuvant may serve as the basis for developing anti-Alzheimer disease vaccines.
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Affiliation(s)
- Ying He
- Department of Medical Genetics, College of Basic Medical Sciences, Second Military Medical University, Shanghai, PR China
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148
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Brasnjevic I, Steinbusch HWM, Schmitz C. Altered gene expression and neuropathology in Alzheimer's disease. Neurobiol Aging 2005; 27:1081-3. [PMID: 16111786 DOI: 10.1016/j.neurobiolaging.2005.05.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2005] [Accepted: 05/02/2005] [Indexed: 11/21/2022]
Affiliation(s)
- Ivona Brasnjevic
- Department of Psychiatry and Neuropsychology, Division of Cellular Neuroscience, Maastricht University, Universiteitssingel 50, 6200 MD Maastricht, The Netherlands
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149
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Spires TL, Meyer-Luehmann M, Stern EA, McLean PJ, Skoch J, Nguyen PT, Bacskai BJ, Hyman BT. Dendritic spine abnormalities in amyloid precursor protein transgenic mice demonstrated by gene transfer and intravital multiphoton microscopy. J Neurosci 2005; 25:7278-87. [PMID: 16079410 PMCID: PMC1820616 DOI: 10.1523/jneurosci.1879-05.2005] [Citation(s) in RCA: 412] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 06/13/2005] [Accepted: 07/01/2005] [Indexed: 12/16/2022] Open
Abstract
Accumulation of amyloid-beta (Abeta) into senile plaques in Alzheimer's disease (AD) is a hallmark neuropathological feature of the disorder, which likely contributes to alterations in neuronal structure and function. Recent work has revealed changes in neurite architecture associated with plaques and functional changes in cortical signaling in amyloid precursor protein (APP) expressing mouse models of AD. Here we developed a method using gene transfer techniques to introduce green fluorescent protein (GFP) into neurons, allowing the investigation of neuronal processes in the vicinity of plaques. Multiphoton imaging of GFP-labeled neurons in living Tg2576 APP mice revealed disrupted neurite trajectories and reductions in dendritic spine density compared with age-matched control mice. A profound deficit in spine density (approximately 50%) extends approximately 20 mum from plaque edges. Importantly, a robust decrement (approximately 25%) also occurs on dendrites not associated with plaques, suggesting widespread loss of postsynaptic apparatus. Plaques and dendrites remained stable over the course of weeks of imaging. Postmortem analysis of axonal immunostaining and colocalization of synaptophysin and postsynaptic density 95 protein staining around plaques indicate a parallel loss of presynaptic and postsynaptic partners. These results show considerable changes in dendrites and dendritic spines in APP transgenic mice, demonstrating a dramatic synaptotoxic effect of dense-cored plaques. Decreased spine density will likely contribute to altered neural system function and behavioral impairments observed in Tg2576 mice.
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Affiliation(s)
- Tara L Spires
- Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
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150
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Kumar-Singh S, Pirici D, McGowan E, Serneels S, Ceuterick C, Hardy J, Duff K, Dickson D, Van Broeckhoven C. Dense-core plaques in Tg2576 and PSAPP mouse models of Alzheimer's disease are centered on vessel walls. THE AMERICAN JOURNAL OF PATHOLOGY 2005; 167:527-43. [PMID: 16049337 PMCID: PMC1603563 DOI: 10.1016/s0002-9440(10)62995-1] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/26/2005] [Indexed: 10/18/2022]
Abstract
Occurrence of amyloid beta (Abeta) dense-core plaques in the brain is one of the chief hallmarks of Alzheimer's disease (AD). It is not yet clear what factors are responsible for the aggregation of Abeta in the formation of these plaques. Using Tg2576 and PSAPP mouse models that exhibit age-related development of amyloid plaques similar to that observed in AD, we showed that approximately 95% of dense plaques in Tg2576 and approximately 85% in PSAPP mice are centered on vessel walls or in the immediate perivascular regions. Stereoscopy and simulation studies focusing on smaller plaques suggested that vascular associations for both Tg2576 and PSAPP mice were dramatically higher than those encountered by chance alone. We further identified ultrastructural microvascular abnormalities occurring in association with dense plaques. Although occurrence of gross cerebral hemorrhage was infrequent, we identified considerable infiltration of the serum proteins immunoglobulin and albumin in association with dense plaques. Together with earlier evidence of vascular clearance of Abeta, our data suggest that perturbed vascular transport and/or perivascular enrichment of Abeta leads to the formation of vasocentric dense plaques in Tg2576 and PSAPP mouse models of AD.
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Affiliation(s)
- Samir Kumar-Singh
- Department of Molecular Genetics VIB8, Neurodegenerative Brain Diseases Research Group, Molecular Neuropathology Project, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium.
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