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The Ubiquitin-Proteasome System and Molecular Chaperone Deregulation in Alzheimer's Disease. Mol Neurobiol 2015; 53:905-931. [PMID: 25561438 DOI: 10.1007/s12035-014-9063-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 12/09/2014] [Indexed: 12/18/2022]
Abstract
One of the shared hallmarks of neurodegenerative diseases is the accumulation of misfolded proteins. Therefore, it is suspected that normal proteostasis is crucial for neuronal survival in the brain and that the malfunction of this mechanism may be the underlying cause of neurodegenerative diseases. The accumulation of amyloid plaques (APs) composed of amyloid-beta peptide (Aβ) aggregates and neurofibrillary tangles (NFTs) composed of misfolded Tau proteins are the defining pathological markers of Alzheimer's disease (AD). The accumulation of these proteins indicates a faulty protein quality control in the AD brain. An impaired ubiquitin-proteasome system (UPS) could lead to negative consequences for protein regulation, including loss of function. Another pivotal mechanism for the prevention of misfolded protein accumulation is the utilization of molecular chaperones. Molecular chaperones, such as heat shock proteins (HSPs) and FK506-binding proteins (FKBPs), are highly involved in protein regulation to ensure proper folding and normal function. In this review, we elaborate on the molecular basis of AD pathophysiology using recent data, with a particular focus on the role of the UPS and molecular chaperones as the defensive mechanism against misfolded proteins that have prion-like properties. In addition, we propose a rational therapy approach based on this mechanism.
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52
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Zou Z, Liu C, Che C, Huang H. Clinical genetics of Alzheimer's disease. BIOMED RESEARCH INTERNATIONAL 2014; 2014:291862. [PMID: 24955352 PMCID: PMC4052685 DOI: 10.1155/2014/291862] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/21/2014] [Indexed: 11/25/2022]
Abstract
Alzheimer's disease (AD) is the most common progressive neurodegenerative disease and the most common form of dementia in the elderly. It is a complex disorder with environmental and genetic components. There are two major types of AD, early onset and the more common late onset. The genetics of early-onset AD are largely understood with mutations in three different genes leading to the disease. In contrast, while susceptibility loci and alleles associated with late-onset AD have been identified using genetic association studies, the genetics of late-onset Alzheimer's disease are not fully understood. Here we review the known genetics of early- and late-onset AD, the clinical features of EOAD according to genotypes, and the clinical implications of the genetics of AD.
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Affiliation(s)
- Zhangyu Zou
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Changyun Liu
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Chunhui Che
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Huapin Huang
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou 350001, China
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53
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Dimitrov M, Alattia JR, Lemmin T, Lehal R, Fligier A, Houacine J, Hussain I, Radtke F, Dal Peraro M, Beher D, Fraering PC. Alzheimer's disease mutations in APP but not γ-secretase modulators affect epsilon-cleavage-dependent AICD production. Nat Commun 2014; 4:2246. [PMID: 23907250 DOI: 10.1038/ncomms3246] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 07/03/2013] [Indexed: 12/29/2022] Open
Abstract
Pathological amino-acid substitutions in the amyloid precursor protein (APP) and chemical γ-secretase modulators affect the processing of APP by the γ-secretase complex and the production of the amyloid-beta peptide Aβ42, the accumulation of which is considered causative of Alzheimer's disease. Here we demonstrate that mutations in the transmembrane domain of APP causing aggressive early-onset familial Alzheimer's disease affect both γ- and ε-cleavage sites, by raising the Aβ42/40 ratio and inhibiting the production of AICD50-99, one of the two physiological APP intracellular domains (ICDs). This is in sharp contrast to γ-secretase modulators, which shift Aβ42 production towards the shorter Aβ38, but unequivocally spare the ε-site and APP- and Notch-ICDs production. Molecular simulations suggest that familial Alzheimer's disease mutations modulate the flexibility of the APP transmembrane domain and the presentation of its γ-site, modifying at the same time, the solvation of the ε-site.
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Affiliation(s)
- Mitko Dimitrov
- Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, CH1015 Lausanne, Switzerland
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54
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Early onset Alzheimer's disease and oxidative stress. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:375968. [PMID: 24669286 PMCID: PMC3942075 DOI: 10.1155/2014/375968] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 11/18/2013] [Indexed: 01/30/2023]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in elderly adults. It is estimated that 10% of the world's population aged more than 60-65 years could currently be affected by AD, and that in the next 20 years, there could be more than 30 million people affected by this pathology. One of the great challenges in this regard is that AD is not just a scientific problem; it is associated with major psychosocial and ethical dilemmas and has a negative impact on national economies. The neurodegenerative process that occurs in AD involves a specific nervous cell dysfunction, which leads to neuronal death. Mutations in APP, PS1, and PS2 genes are causes for early onset AD. Several animal models have demonstrated that alterations in these proteins are able to induce oxidative damage, which in turn favors the development of AD. This paper provides a review of many, although not all, of the mutations present in patients with familial Alzheimer's disease and the association between some of these mutations with both oxidative damage and the development of the pathology.
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55
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Perez-Garmendia R, Gevorkian G. Pyroglutamate-Modified Amyloid Beta Peptides: Emerging Targets for Alzheimer´s Disease Immunotherapy. Curr Neuropharmacol 2014; 11:491-8. [PMID: 24403873 PMCID: PMC3763757 DOI: 10.2174/1570159x11311050004] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 03/16/2013] [Accepted: 03/28/2013] [Indexed: 12/25/2022] Open
Abstract
Extracellular and intraneuronal accumulation of amyloid-beta (Aβ) peptide aggregates in the brain has been hypothesized to play an important role in the neuropathology of Alzheimer’s Disease (AD). The main Aβ variants detected in the human brain are Aβ1-40 and Aβ1-42, however a significant proportion of AD brain Aβ consists also of N-terminal truncated species. Pyroglutamate-modified Aβ peptides have been demonstrated to be the predominant components among all N-terminal truncated Aβ species in AD brains and represent highly desirable and abundant therapeutic targets. The current review describes the properties and localization of two pyroglutamate-modified Aβ peptides, AβN3(pE) and AβN11(pE), in the brain. The role of glutaminyl cyclase (QC) in the formation of these peptides is also addressed. In addition, two potential therapeutic strategies, the inhibition of QC and immunotherapy approaches, and clinical trials aimed to target these important pathological Aβ species are reviewed.
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Affiliation(s)
- Roxanna Perez-Garmendia
- Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico (UNAM), Mexico DF, Mexico
| | - Goar Gevorkian
- Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico (UNAM), Mexico DF, Mexico
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56
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57
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Suárez-Calvet M, Belbin O, Pera M, Badiola N, Magrané J, Guardia-Laguarta C, Muñoz L, Colom-Cadena M, Clarimón J, Lleó A. Autosomal-dominant Alzheimer's disease mutations at the same codon of amyloid precursor protein differentially alter Aβ production. J Neurochem 2013; 128:330-9. [PMID: 24117942 DOI: 10.1111/jnc.12466] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 09/20/2013] [Accepted: 10/24/2013] [Indexed: 02/02/2023]
Abstract
Autosomal-dominant Alzheimer's disease (ADAD) is a genetic disorder caused by mutations in Amyloid Precursor Protein (APP) or Presenilin (PSEN) genes. Studying the mechanisms underlying these mutations can provide insight into the pathways that lead to AD pathology. The majority of biochemical studies on APP mutations to-date have focused on comparing mechanisms between mutations at different codons. It has been assumed that amino acid position is a major determinant of protein dysfunction and clinical phenotype. However, the differential effect of mutations at the same codon has not been sufficiently addressed. In the present study we compared the effects of the aggressive ADAD-associated APP I716F mutation with I716V and I716T on APP processing in human neuroglioma and CHO-K1 cells. All APP I716 mutations increased the ratio of Aβ42/40 and changed the product line preference of γ-secretase towards Aβ38 production. In addition, the APP I716F mutation impaired the ε-cleavage and the fourth cleavage of γ-secretase and led to abnormal APP β-CTF accumulation at the plasma membrane. Taken together, these data indicate that APP mutations at the same codon can induce diverse abnormalities in APP processing, some resembling PSEN1 mutations. These differential effects could explain the clinical differences observed among ADAD patients bearing different APP mutations at the same position. The amyloid precursor protein (APP) I716F mutation is associated with autosomal dominant Alzheimer's disease with the youngest age-at-onset for the APP locus. Here, we describe that this mutation, when compared to two other familial Alzheimer's disease mutations at the same codon (I716V and I716T), interfered distinctly with γ-secretase cleavage. While all three mutations direct γ-secretase cleavage towards the 48→38 production line, the APP I716F mutation also impaired the ε-cleavage and the fourth cleavage of γ-secretase, resembling a PSEN1 mutation. These features may contribute to the aggressiveness of this mutation.
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Affiliation(s)
- Marc Suárez-Calvet
- Department of Neurology, Memory Disorders Unit, Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Alzheimer Laboratory, Neurology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
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58
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Hausner L, Tschäpe JA, Schmitt HP, Hentschel F, Hartmann T, Frölich L. Clinical characterization of a presenilin 1 mutation (F177S) in a family with very early‐onset Alzheimer's disease in the third decade of life. Alzheimers Dement 2013; 10:e27-39. [DOI: 10.1016/j.jalz.2013.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 01/09/2013] [Accepted: 02/06/2013] [Indexed: 10/26/2022]
Affiliation(s)
- Lucrezia Hausner
- Department of Geriatric Psychiatry, Central Institute of Mental Health, Medical Faculty MannheimUniversity of HeidelbergHeidelbergGermany
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty MannheimUniversity of HeidelbergHeidelbergGermany
| | - Jakob A. Tschäpe
- Department of Neurodegeneration and NeurobiologySaarland UniversitySaarbrueckkenGermany
- Department of NeurologySaarland UniversitySaarbrueckkenGermany
| | | | - Frank Hentschel
- Department of Neuroradiology, Central Institute of Mental Health, Medical Faculty MannheimUniversity of HeidelbergHeidelbergGermany
| | - Tobias Hartmann
- Department of Neurodegeneration and NeurobiologySaarland UniversitySaarbrueckkenGermany
- Department of NeurologySaarland UniversitySaarbrueckkenGermany
| | - Lutz Frölich
- Department of Geriatric Psychiatry, Central Institute of Mental Health, Medical Faculty MannheimUniversity of HeidelbergHeidelbergGermany
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59
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Lin S, Liu H, Kanawati B, Liu L, Dong J, Li M, Huang J, Schmitt-Kopplin P, Cai Z. Hippocampal metabolomics using ultrahigh-resolution mass spectrometry reveals neuroinflammation from Alzheimer's disease in CRND8 mice. Anal Bioanal Chem 2013; 405:5105-17. [PMID: 23494273 DOI: 10.1007/s00216-013-6825-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 02/02/2013] [Accepted: 02/06/2013] [Indexed: 12/24/2022]
Abstract
In the wake of genomics, metabolomics characterizes the small molecular metabolites revealing the phenotypes induced by gene mutants. To address the metabolic signatures in the hippocampus of the amyloid-beta (Aβ) peptides produced in transgenic (Tg) CRND8 mice, high-field ion cyclotron resonance-Fourier transform mass spectrometry supported by LC-LTQ-Orbitrap was introduced to profile the extracted metabolites. More than 10,000 ions were detected in the mass profile for each sample. Subsequently, peak alignment and the 80% rule followed by feature selection based on T score computation were performed. The putative identification was also conducted using the highly accurate masses with isotopic distribution by interfacing the MassTRIX database as well as MS/MS fragmentation generated in the LTQ-Orbitrap after chromatographic separation. Consequently, 58 differentiating masses were tentatively identified while up to 44 differentiating elemental compositions could not be biologically annotated in the databases. Nonetheless, of the putatively annotated masses, eicosanoids in arachidonic acid metabolism, fatty acid beta-oxidation disorders as well as disturbed glucose metabolism were highlighted as metabolic traits of Aβ toxicity in Tg CRND8 mice. Furthermore, a web-based bioinformatic tool was used for simulation of the metabolic pathways. As a result of the obtained metabolic signatures, the arachidonic acid metabolism dominates the metabolic perturbation in hippocampal tissues of Tg CRND8 mice compared to non-Tg littermates, indicating that Aβ toxicity functions neuroinflammation in hippocampal tissue and new theranostic opportunities might be offered by characterization of altered arachidonic acid metabolism for Alzheimer's disease.
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Affiliation(s)
- Shuhai Lin
- Department of Chemistry, Hong Kong Baptist University, Hong Kong, SAR, China
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60
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Pester O, Barrett PJ, Hornburg D, Hornburg P, Pröbstle R, Widmaier S, Kutzner C, Dürrbaum M, Kapurniotu A, Sanders CR, Scharnagl C, Langosch D. The backbone dynamics of the amyloid precursor protein transmembrane helix provides a rationale for the sequential cleavage mechanism of γ-secretase. J Am Chem Soc 2013; 135:1317-29. [PMID: 23265086 PMCID: PMC3560327 DOI: 10.1021/ja3112093] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The etiology of Alzheimer's disease depends on the relative abundance of different amyloid-β (Aβ) peptide species. These peptides are produced by sequential proteolytic cleavage within the transmembrane helix of the 99 residue C-terminal fragment of the amyloid precursor protein (C99) by the intramembrane protease γ-secretase. Intramembrane proteolysis is thought to require local unfolding of the substrate helix, which has been proposed to be cleaved as a homodimer. Here, we investigated the backbone dynamics of the substrate helix. Amide exchange experiments of monomeric recombinant C99 and of synthetic transmembrane domain peptides reveal that the N-terminal Gly-rich homodimerization domain exchanges much faster than the C-terminal cleavage region. MD simulations corroborate the differential backbone dynamics, indicate a bending motion at a diglycine motif connecting dimerization and cleavage regions, and detect significantly different H-bond stabilities at the initial cleavage sites. Our results are consistent with the following hypotheses about cleavage of the substrate: First, the GlyGly hinge may precisely position the substrate within γ-secretase such that its catalytic center must start proteolysis at the known initial cleavage sites. Second, the ratio of cleavage products formed by subsequent sequential proteolysis could be influenced by differential extents of solvation and by the stabilities of H-bonds at alternate initial sites. Third, the flexibility of the Gly-rich domain may facilitate substrate movement within the enzyme during sequential proteolysis. Fourth, dimerization may affect substrate processing by decreasing the dynamics of the dimerization region and by increasing that of the C-terminal part of the cleavage region.
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Affiliation(s)
- Oxana Pester
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Paul J. Barrett
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, Tennessee USA 37232-8725
| | - Daniel Hornburg
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Philipp Hornburg
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Rasmus Pröbstle
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Simon Widmaier
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Christoph Kutzner
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Milena Dürrbaum
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
| | - Aphrodite Kapurniotu
- Fachgebiet Peptidbiochemie, Technische Universität München, Emil-Erlenmeyer-Forum 5, 85354 Freising, Germany
| | - Charles R. Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, Tennessee USA 37232-8725
| | - Christina Scharnagl
- Fakultät für Physik E14, Technische Universität München, Maximus-von-Imhof-Forum 4, 85354 Freising, Germany
| | - Dieter Langosch
- Lehrstuhl Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, and Munich Center For Integrated Protein Science (CIPS), Germany
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61
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Malyshev I. The Role of HSP70 in the Protection of: (A) The Brain in Alzheimer’s Disease and (B) The Heart in Cardiac Surgery. IMMUNITY, TUMORS AND AGING: THE ROLE OF HSP70 2013. [DOI: 10.1007/978-94-007-5943-5_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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62
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Esselens C, Sannerud R, Gallardo R, Baert V, Kaden D, Serneels L, De Strooper B, Rousseau F, Multhaup G, Schymkowitz J, Langedijk JPM, Annaert W. Peptides based on the presenilin-APP binding domain inhibit APP processing and Aβ production through interfering with the APP transmembrane domain. FASEB J 2012; 26:3765-78. [PMID: 22661005 DOI: 10.1096/fj.11-201368] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Presenilins (PSENs) form the catalytic component of the γ-secretase complex, responsible for intramembrane proteolysis of amyloid precursor protein (APP) and Notch, among many other membrane proteins. Previously, we identified a PSEN1-binding domain in APP, encompassing half of the transmembrane domain following the amyloid β (Aβ) sequence. Based on this, we designed peptides mimicking this interaction domain with the aim to selectively block APP processing and Aβ generation through interfering with enzyme-substrate binding. We identified a peptide sequence that, when fused to a virally derived translocation peptide, significantly lowered Aβ production (IC(50): 317 nM) in cell-free and cell-based assays using APP-carboxy terminal fragment as a direct γ-secretase substrate. Being derived from the APP sequence, this inhibitory peptide did not affect NotchΔE γ-cleavage, illustrating specificity and potential therapeutic value. In cell-based assays, the peptide strongly suppressed APP shedding, demonstrating that it exerts the inhibitory effect already upstream of γ-secretase, most likely through steric hindrance.
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Affiliation(s)
- Cary Esselens
- Laboratory for Membrane Trafficking, Center for Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium
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63
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Weggen S, Beher D. Molecular consequences of amyloid precursor protein and presenilin mutations causing autosomal-dominant Alzheimer's disease. ALZHEIMERS RESEARCH & THERAPY 2012; 4:9. [PMID: 22494386 PMCID: PMC3334542 DOI: 10.1186/alzrt107] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Mutations in both the amyloid precursor protein (APP) and the presenilin (PSEN) genes cause familial Alzheimer's disease (FAD) with autosomal dominant inheritance and early onset of disease. The clinical course and neuropathology of FAD and sporadic Alzheimer's disease are highly similar, and patients with FAD constitute a unique population in which to conduct treatment and, in particular, prevention trials with novel pharmaceutical entities. It is critical, therefore, to exactly defi ne the molecular consequences of APP and PSEN FAD mutations. Both APP and PSEN mutations drive amyloidosis in FAD patients through changes in the brain metabolism of amyloid-β (Aβ) peptides that promote the formation of pathogenic aggregates. APP mutations do not seem to impair the physiological functions of APP. In contrast, it has been proposed that PSEN mutations compromise γ-secretase-dependent and -independent functions of PSEN. However, PSEN mutations have mostly been studied in model systems that do not accurately refl ect the genetic background in FAD patients. In this review, we discuss the reported cellular phenotypes of APP and PSEN mutations, the current understanding of their molecular mechanisms, the need to generate faithful models of PSEN mutations, and the potential bias of APP and PSEN mutations on therapeutic strategies that target Aβ.
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Affiliation(s)
- Sascha Weggen
- Department of Neuropathology, Heinrich-Heine-University, Moorenstrasse 5, D-40225 Düsseldorf, Germany.
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64
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Moraes CF, Lins TC, Carmargos EF, Naves JOS, Pereira RW, Nóbrega OT. Lessons from genome-wide association studies findings in Alzheimer's disease. Psychogeriatrics 2012; 12:62-73. [PMID: 22416831 DOI: 10.1111/j.1479-8301.2011.00378.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disorder with a complex genetic background. Recent genome-wide association studies (GWAS) have placed important new contributors into the genetic framework of early- and late-onset forms of this dementia. Besides confirming the major role of classic allelic variants (e.g. apolipoprotein E) in the development of AD, GWAS have thus far implicated over 20 single nucleotide polymorphisms in AD. In this review, we summarize the findings of 16 AD-based GWAS performed to date whose public registries are available at the National Human Genome Research Institute, with an emphasis on understanding whether the polymorphic markers under consideration support functional implications to the pathophysiological role of the major genetic risk factors unraveled by GWAS.
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Affiliation(s)
- Clayton F Moraes
- Geriatric Service, Hospital of the Catholic University of Brasília, Graduate Program in Medical Sciences, University of Brasília, Brasília - DF, Brazil
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65
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Lu JX, Yau WM, Tycko R. Evidence from solid-state NMR for nonhelical conformations in the transmembrane domain of the amyloid precursor protein. Biophys J 2011; 100:711-719. [PMID: 21281586 DOI: 10.1016/j.bpj.2010.12.3696] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 10/22/2010] [Accepted: 12/08/2010] [Indexed: 02/03/2023] Open
Abstract
The amyloid precursor protein (APP) is subject to proteolytic processing by γ-secretase within neuronal membranes, leading to Alzheimer's disease-associated β-amyloid peptide production by cleavage near the midpoint of the single transmembrane (TM) segment of APP. Conformational properties of the TM segment may affect its susceptibility to γ-secretase cleavage, but these properties have not been established definitively, especially in bilayer membranes with physiologically relevant lipid compositions. In this article, we report an investigation of the APP-TM conformation, using (13)C chemical shifts obtained with two-dimensional solid-state NMR spectroscopy as site-specific conformational probes. We find that the APP-TM conformation is not a simple α-helix, particularly at 37°C in multilamellar vesicles with compositions that mimic the composition of neuronal cell membranes. Instead, we observe a mixture of helical and nonhelical conformations at the N- and C-termini and in the vicinity of the γ-cleavage site. Conformational plasticity of the TM segment of APP may be an important factor in the γ-secretase cleavage mechanism.
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Affiliation(s)
- Jun-Xia Lu
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland.
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66
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Wang H, Barreyro L, Provasi D, Djemil I, Torres-Arancivia C, Filizola M, Ubarretxena-Belandia I. Molecular determinants and thermodynamics of the amyloid precursor protein transmembrane domain implicated in Alzheimer's disease. J Mol Biol 2011; 408:879-95. [PMID: 21440556 DOI: 10.1016/j.jmb.2011.03.028] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 03/03/2011] [Accepted: 03/14/2011] [Indexed: 01/02/2023]
Abstract
The deposition of toxic amyloid-β (Aβ) peptide aggregates in the brain is a hallmark of Alzheimer's disease. The intramembrane proteolysis by γ-secretase of the amyloid precursor protein β-carboxy-terminal fragment (APP-βCTF) constitutes the final step in the production of Aβ peptides. Mounting evidence suggests that APP-βCTF is a transmembrane domain (TMD) dimer, and that dimerization might modulate the production of Aβ species that are prone to aggregation and are therefore most toxic. We combined experimental and computational approaches to study the molecular determinants and thermodynamics of APP-βCTF dimerization, and we produced a unifying structural model that reconciles much of the published data. Using a cell assay that exploits a dimerization-dependent activator of transcription, we identified specific dimerization-affecting mutations located mostly at the N-terminus of the TMD of APP-βCTF. The ability of selected mutants to affect the dimerization of full-length APP-βCTF was confirmed by fluorescence resonance energy transfer experiments. Free-energy estimates of the wild type and mutants of the TMD of APP-βCTF derived from enhanced molecular dynamics simulations showed that the dimeric state is composed of different arrangements, in which either (709)GXXXA(713) or (700)GXXXG(704)GXXXG(708) interaction motifs can engage in symmetric or asymmetric associations. Mutations along the TMD of APP-βCTF were found to modulate the relative free energy of the dimeric configurations and to differently affect the distribution of interfaces within the dimeric state. This observation might have important biological implications, since dimers with a different arrangement of the transmembrane helices are likely to be recognized differently by γ-secretase and to lead to a variation in Aβ levels.
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Affiliation(s)
- Hao Wang
- Department of Structural and Chemical Biology, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA
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67
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Giaccone G, Morbin M, Moda F, Botta M, Mazzoleni G, Uggetti A, Catania M, Moro ML, Redaelli V, Spagnoli A, Rossi RS, Salmona M, Di Fede G, Tagliavini F. Neuropathology of the recessive A673V APP mutation: Alzheimer disease with distinctive features. Acta Neuropathol 2010; 120:803-12. [PMID: 20842367 DOI: 10.1007/s00401-010-0747-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 09/02/2010] [Accepted: 09/05/2010] [Indexed: 11/25/2022]
Abstract
Mutations of three different genes, encoding β-amyloid precursor protein (APP), presenilin 1 and presenilin 2 are associated with familial Alzheimer's disease (AD). Recently, the APP mutation A673V has been identified that stands out from all the genetic defects previously reported in these three genes, since it causes the disease only in the homozygous state (Di Fede et al. in Science 323:1473-1477, 2009). We here provide the detailed neuropathological picture of the proband of this family, who was homozygous for the APP A673V mutation and recently came to death. The brain has been studied by histological and immunohistochemical techniques, at the optical and ultrastructural levels. Cerebral Aβ accumulation and tau pathology were severe and extensive. Peculiar features were the configuration of the Aβ deposits that were of large size, mostly perivascular and exhibited a close correspondence between the pattern elicited by amyloid stainings and the labeling obtained with immunoreagents specific for Aβ40 or Aβ42. Moreover, Aβ deposition spared the neostriatum while deeply affecting the cerebellum, and therefore was not in compliance with the hierarchical topographical sequence of involvement documented in sporadic AD. Therefore, the neuropathological picture of familial AD caused by the APP recessive mutation A673V presents distinctive characteristics compared to sporadic AD or familial AD inherited as a dominant trait. Main peculiar features are the morphology, structural properties and composition of the Aβ deposits as well as their topographic distribution in the brain.
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Affiliation(s)
- Giorgio Giaccone
- Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
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68
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Anti-11[E]-pyroglutamate-modified amyloid β antibodies cross-react with other pathological Aβ species: relevance for immunotherapy. J Neuroimmunol 2010; 229:248-55. [PMID: 20864186 DOI: 10.1016/j.jneuroim.2010.08.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 08/24/2010] [Accepted: 08/26/2010] [Indexed: 12/15/2022]
Abstract
N-truncated/modified forms of amyloid beta (Aß) peptide are found in diffused and dense core plaques in Alzheimer's disease (AD) and Down's syndrome patients as well as animal models of AD, and represent highly desirable therapeutic targets. In the present study we have focused on N-truncated/modified Aβ peptide bearing amino-terminal pyroglutamate at position 11 (AβN11(pE)). We identified two B-cell epitopes recognized by rabbit anti-AβN11(pE) polyclonal antibodies. Interestingly, rabbit anti-AβN11(pE) polyclonal antibodies bound also to full-length Aβ1-42 and N-truncated/modified AβN3(pE), suggesting that the three peptides may share a common B-cell epitope. Importantly, rabbit anti-AβN11(pE) antibodies bound to naturally occurring Aβ aggregates present in brain samples from AD patients. These results are potentially important for developing novel immunogens for targeting N-truncated/modified Aβ aggregates as well, since the most commonly used immunogens in the majority of vaccine studies have been shown to induce antibodies that recognize the N-terminal immunodominant epitope (EFRH) of the full length Aβ, which is absent in N-amino truncated peptides.
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69
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Jaworski T, Kügler S, Van Leuven F. Modeling of tau-mediated synaptic and neuronal degeneration in Alzheimer's disease. Int J Alzheimers Dis 2010; 2010. [PMID: 20862366 PMCID: PMC2938448 DOI: 10.4061/2010/573138] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 07/09/2010] [Indexed: 12/22/2022] Open
Abstract
Patients suffering from Alzheimer's disease (AD) are typified and diagnosed postmortem by the combined accumulations of extracellular amyloid plaques and of intracellular tauopathy, consisting of neuropil treads and neurofibrillary tangles in the somata. Both hallmarks are inseparable and remain diagnostic as described by Alois Alzheimer more than a century ago. Nevertheless, these pathological features are largely abandoned as being the actual pathogenic or neurotoxic factors. The previous, almost exclusive experimental attention on amyloid has shifted over the last 10 years in two directions. Firstly, from the “concrete” deposits of amyloid plaques to less well-defined soluble or pseudosoluble oligomers of the amyloid peptides, ranging from dimers to dodecamers and even larger aggregates. A second shift in research focus is from amyloid to tauopathy, and to their mutual relation. The role of Tau in the pathogenesis and disease progression is appreciated as leading to synaptic and neuronal loss, causing cognitive deficits and dementia. Both trends are incorporated in a modified amyloid cascade hypothesis, briefly discussed in this paper that is mainly concerned with the second aspect, that is, protein Tau and its associated fundamental questions.
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Affiliation(s)
- Tomasz Jaworski
- Experimental Genetics Group, Department of Human Genetics, KULeuven-Campus Gasthuisberg ON1-06.602, Herestraat 49, 3000 Leuven, Belgium
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70
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Munter LM, Botev A, Richter L, Hildebrand PW, Althoff V, Weise C, Kaden D, Multhaup G. Aberrant amyloid precursor protein (APP) processing in hereditary forms of Alzheimer disease caused by APP familial Alzheimer disease mutations can be rescued by mutations in the APP GxxxG motif. J Biol Chem 2010; 285:21636-43. [PMID: 20452985 PMCID: PMC2898405 DOI: 10.1074/jbc.m109.088005] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 05/07/2010] [Indexed: 01/01/2023] Open
Abstract
The identification of hereditary familial Alzheimer disease (FAD) mutations in the amyloid precursor protein (APP) and presenilin-1 (PS1) corroborated the causative role of amyloid-beta peptides with 42 amino acid residues (Abeta42) in the pathogenesis of AD. Although most FAD mutations are known to increase Abeta42 levels, mutations within the APP GxxxG motif are known to lower Abeta42 levels by attenuating transmembrane sequence dimerization. Here, we show that aberrant Abeta42 levels of FAD mutations can be rescued by GxxxG mutations. The combination of the APP-GxxxG mutation G33A with APP-FAD mutations yielded a constant 60% decrease of Abeta42 levels and a concomitant 3-fold increase of Abeta38 levels compared with the Gly(33) wild-type as determined by ELISA. In the presence of PS1-FAD mutations, the effects of G33A were attenuated, apparently attributable to a different mechanism of PS1-FAD mutants compared with APP-FAD mutants. Our results contribute to a general understanding of the mechanism how APP is processed by the gamma-secretase module and strongly emphasize the potential of the GxxxG motif in the prevention of sporadic AD as well as FAD.
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Affiliation(s)
- Lisa-Marie Munter
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany and
| | - Anne Botev
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany and
| | - Luise Richter
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany and
| | - Peter W. Hildebrand
- the Institut für Medizinische Physik und Biophysik, Charité, 10117 Berlin, Germany
| | - Veit Althoff
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany and
| | - Christoph Weise
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany and
| | - Daniela Kaden
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany and
| | - Gerd Multhaup
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany and
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71
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Gouras GK, Tampellini D, Takahashi RH, Capetillo-Zarate E. Intraneuronal beta-amyloid accumulation and synapse pathology in Alzheimer's disease. Acta Neuropathol 2010; 119:523-41. [PMID: 20354705 PMCID: PMC3183823 DOI: 10.1007/s00401-010-0679-9] [Citation(s) in RCA: 240] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 03/23/2010] [Accepted: 03/23/2010] [Indexed: 01/01/2023]
Abstract
The aberrant accumulation of aggregated beta-amyloid peptides (Abeta) as plaques is a hallmark of Alzheimer's disease (AD) neuropathology and reduction of Abeta has become a leading direction of emerging experimental therapies for the disease. The mechanism(s) whereby Abeta is involved in the pathophysiology of the disease remain(s) poorly understood. Initially fibrils, and subsequently oligomers of extracellular Abeta have been viewed as the most important pathogenic form of Abeta in AD. More recently, the intraneuronal accumulation of Abeta has been described in the brain, although technical considerations and its relevance in AD have made this a controversial topic. Here, we review the emerging evidence linking intraneuronal Abeta accumulation to the development of synaptic pathology and plaques in AD, and discuss the implications of intraneuronal beta-amyloid for AD pathology, biology, diagnosis and therapy.
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Affiliation(s)
- Gunnar K Gouras
- Department for Neurology and Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA.
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72
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Page RM, Gutsmiedl A, Fukumori A, Winkler E, Haass C, Steiner H. Beta-amyloid precursor protein mutants respond to gamma-secretase modulators. J Biol Chem 2010; 285:17798-810. [PMID: 20348104 DOI: 10.1074/jbc.m110.103283] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pathogenic generation of the 42-amino acid variant of the amyloid beta-peptide (Abeta) by beta- and gamma-secretase cleavage of the beta-amyloid precursor protein (APP) is believed to be causative for Alzheimer disease (AD). Lowering of Abeta(42) production by gamma-secretase modulators (GSMs) is a hopeful approach toward AD treatment. The mechanism of GSM action is not fully understood. Moreover, whether GSMs target the Abeta domain is controversial. To further our understanding of the mode of action of GSMs and the cleavage mechanism of gamma-secretase, we analyzed mutations located at different positions of the APP transmembrane domain around or within the Abeta domain regarding their response to GSMs. We found that Abeta(42)-increasing familial AD mutations of the gamma-secretase cleavage site domain responded robustly to Abeta(42)-lowering GSMs, especially to the potent compound GSM-1, irrespective of the amount of Abeta(42) produced. We thus expect that familial AD patients carrying mutations at the gamma-secretase cleavage sites of APP should respond to GSM-based therapeutic approaches. Systematic phenylalanine-scanning mutagenesis of this region revealed a high permissiveness to GSM-1 and demonstrated a complex mechanism of GSM action as other Abeta species (Abeta(41), Abeta(39)) could also be lowered besides Abeta(42). Moreover, certain mutations simultaneously increased Abeta(42) and the shorter peptide Abeta(38), arguing that the proposed precursor-product relationship of these Abeta species is not general. Finally, mutations of residues in the proposed GSM-binding site implicated in Abeta(42) generation (Gly-29, Gly-33) and potentially in GSM-binding (Lys-28) were also responsive to GSMs, a finding that may question APP substrate targeting of GSMs.
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Affiliation(s)
- Richard M Page
- German Center for Neurodegenerative Diseases DZNE)and Adolf-Butenandt-Institute, Biochemistry, Ludwig-Maximilians-University, 80336 Munich, Germany
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73
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Bayer TA, Wirths O. Intracellular accumulation of amyloid-Beta - a predictor for synaptic dysfunction and neuron loss in Alzheimer's disease. Front Aging Neurosci 2010; 2:8. [PMID: 20552046 PMCID: PMC2879032 DOI: 10.3389/fnagi.2010.00008] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Accepted: 02/12/2010] [Indexed: 11/15/2022] Open
Abstract
Despite of long-standing evidence that beta-amyloid (Abeta) peptides have detrimental effects on synaptic function, the relationship between Abeta, synaptic and neuron loss is largely unclear. During the last years there is growing evidence that early intraneuronal accumulation of Abeta peptides is one of the key events leading to synaptic and neuronal dysfunction. Many studies have been carried out using transgenic mouse models of Alzheimer's disease (AD) which have been proven to be valuable model systems in modern AD research. The present review discusses the impact of intraneuronal Abeta accumulation on synaptic impairment and neuron loss and provides an overview of currently available AD mouse models showing these pathological alterations.
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Affiliation(s)
- Thomas A. Bayer
- Division of Molecular Psychiatry and Alzheimer Ph.D. Graduate School, Department of Psychiatry, University of GöttingenGöttingen, Germany
| | - Oliver Wirths
- Division of Molecular Psychiatry and Alzheimer Ph.D. Graduate School, Department of Psychiatry, University of GöttingenGöttingen, Germany
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74
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Pirici D, Van Cauwenberghe C, Van Broeckhoven C, Kumar-Singh S. Fractal analysis of amyloid plaques in Alzheimer's disease patients and mouse models. Neurobiol Aging 2009; 32:1579-87. [PMID: 20015575 DOI: 10.1016/j.neurobiolaging.2009.10.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 10/01/2009] [Accepted: 10/18/2009] [Indexed: 12/30/2022]
Abstract
The varied morphological and biochemical forms in which amyloid deposits in brain of Alzheimer's disease (AD) patients are complex and their mechanisms of formation are not completely understood. Here we investigated the ability of fractal dimension (FD) to differentiate between the textures of commonly observed amyloid plaques in sporadic and familial AD patients and aged-control individuals as well as in transgenic mouse models of amyloidosis. Studying more than 6000 amyloid plaques immunostained for total Aβ (Aβt), Aβ40 or Aβ42, we show here that Aβ40 FD could efficiently differentiate between (i) AD patients and aged-control individuals (P<0.001); (ii) sporadic and familial AD due to presenilin-1 or APP (A692G) mutations (P<0.001); and (iii) three transgenic mouse models of different genotypes (P<0.001). Furthermore, while diffuse and dense-core plaques present in humans and transgenic mice had comparable FDs, both Aβt and Aβ42 FD could also differentiate diffuse plaques from other plaque types in both species (P<0.001). Our data suggest that plaque FD could be a valuable tool for objective, computer-oriented AD diagnosis as well as for genotype-phenotype correlations of AD.
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Affiliation(s)
- Daniel Pirici
- Neurodegenerative Brain Diseases Group, Department of Molecular Genetics, VIB, Antwerpen, Belgium
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75
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Jaworski T, Dewachter I, Lechat B, Croes S, Termont A, Demedts D, Borghgraef P, Devijver H, Filipkowski RK, Kaczmarek L, Kügler S, Van Leuven F. AAV-tau mediates pyramidal neurodegeneration by cell-cycle re-entry without neurofibrillary tangle formation in wild-type mice. PLoS One 2009; 4:e7280. [PMID: 19794916 PMCID: PMC2748684 DOI: 10.1371/journal.pone.0007280] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 08/28/2009] [Indexed: 12/21/2022] Open
Abstract
In Alzheimer's disease tauopathy is considered secondary to amyloid, and the duality obscures their relation and the definition of their respective contributions.Transgenic mouse models do not resolve this problem conclusively, i.e. the relative hierarchy of amyloid and tau pathology depends on the actual model and the genes expressed or inactivated. Here, we approached the problem in non-transgenic models by intracerebral injection of adeno-associated viral vectors to express protein tau or amyloid precursor protein in the hippocampus in vivo. AAV-APP mutant caused neuronal accumulation of amyloid peptides, and eventually amyloid plaques at 6 months post-injection, but with only marginal hippocampal cell-death. In contrast, AAV-Tau, either wild-type or mutant P301L, provoked dramatic degeneration of pyramidal neurons in CA1/2 and cortex within weeks. Tau-mediated neurodegeneration proceeded without formation of large fibrillar tau-aggregates or tangles, but with increased expression of cell-cycle markers.We present novel AAV-based models, which demonstrate that protein tau mediates pyramidal neurodegeneration in vivo. The data firmly support the unifying hypothesis that post-mitotic neurons are forced to re-enter the cell-cycle in primary and secondary tauopathies, including Alzheimer's disease.
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Affiliation(s)
- Tomasz Jaworski
- Experimental Genetics Group, Department of Human Genetics, KULeuven-Campus, Leuven, Belgium
| | - Ilse Dewachter
- Experimental Genetics Group, Department of Human Genetics, KULeuven-Campus, Leuven, Belgium
| | - Benoit Lechat
- Experimental Genetics Group, Department of Human Genetics, KULeuven-Campus, Leuven, Belgium
| | - Sophie Croes
- Experimental Genetics Group, Department of Human Genetics, KULeuven-Campus, Leuven, Belgium
| | - Annelies Termont
- Experimental Genetics Group, Department of Human Genetics, KULeuven-Campus, Leuven, Belgium
| | - David Demedts
- Experimental Genetics Group, Department of Human Genetics, KULeuven-Campus, Leuven, Belgium
| | - Peter Borghgraef
- Experimental Genetics Group, Department of Human Genetics, KULeuven-Campus, Leuven, Belgium
| | - Herman Devijver
- Experimental Genetics Group, Department of Human Genetics, KULeuven-Campus, Leuven, Belgium
| | | | - Leszek Kaczmarek
- Lab of Molecular Neurobiology, Nencki Institute, Warszawa, Poland
| | - Sebastian Kügler
- Center of Molecular Physiology of the Brain (CMPB), Department of Neurology, University Medicine Göttingen, Göttingen, Germany
| | - Fred Van Leuven
- Experimental Genetics Group, Department of Human Genetics, KULeuven-Campus, Leuven, Belgium
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76
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Sarsoza F, Saing T, Kayed R, Dahlin R, Dick M, Broadwater-Hollifield C, Mobley S, Lott I, Doran E, Gillen D, Anderson-Bergman C, Cribbs DH, Glabe C, Head E. A fibril-specific, conformation-dependent antibody recognizes a subset of Abeta plaques in Alzheimer disease, Down syndrome and Tg2576 transgenic mouse brain. Acta Neuropathol 2009; 118:505-17. [PMID: 19360426 PMCID: PMC2737113 DOI: 10.1007/s00401-009-0530-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Revised: 03/11/2009] [Accepted: 03/29/2009] [Indexed: 12/20/2022]
Abstract
Beta-amyloid (Abeta) is thought to be a key contributor to the pathogenesis of Alzheimer disease (AD) in the general population and in adults with Down syndrome (DS). Different assembly states of Abeta have been identified that may be neurotoxic. Abeta oligomers can assemble into soluble prefibrillar oligomers, soluble fibrillar oligomers and insoluble fibrils. Using a novel antibody, OC, recognizing fibrils and soluble fibrillar oligomers, we characterized fibrillar Abeta deposits in AD and DS cases. We further compared human specimens to those obtained from the Tg2576 mouse model of AD. Our results show that accumulation of fibrillar immunoreactivity is significantly increased in AD relative to nondemented aged subjects and those with select cognitive impairments (p < 0.0001). Further, there was a significant correlation between the extent of frontal cortex fibrillar deposit accumulation and dementia severity (MMSE r = -0.72). In DS, we observe an early age of onset and age-dependent accumulation of fibrillar OC immunoreactivity with little pathology in similarly aged non-DS individuals. Tg2576 mice show fibrillar accumulation that can be detected as young as 6 months. Interestingly, fibril-specific immunoreactivity was observed in diffuse, thioflavine S-negative Abeta deposits in addition to more mature neuritic plaques. These results suggest that fibrillar deposits are associated with disease in both AD and in adults with DS and their distribution within early Abeta pathology associated with diffuse plaques and correlation with MMSE suggest that these deposits may not be as benign as previously thought.
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Affiliation(s)
- Floyd Sarsoza
- Institute for Brain Aging and Dementia, University of California, Irvine, CA 92697 USA
| | - Tommy Saing
- Institute for Brain Aging and Dementia, University of California, Irvine, CA 92697 USA
| | - Rakez Kayed
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697 USA
| | - Robert Dahlin
- Institute for Brain Aging and Dementia, University of California, Irvine, CA 92697 USA
| | - Malcolm Dick
- Institute for Brain Aging and Dementia, University of California, Irvine, CA 92697 USA
| | | | - Scott Mobley
- Institute for Brain Aging and Dementia, University of California, Irvine, CA 92697 USA
| | - Ira Lott
- Institute for Brain Aging and Dementia, University of California, Irvine, CA 92697 USA
- Department of Neurology, University of California, Irvine, CA 92697 USA
- Department of Pediatrics, University of California, Irvine, CA 92697 USA
| | - Eric Doran
- Institute for Brain Aging and Dementia, University of California, Irvine, CA 92697 USA
- Department of Pediatrics, University of California, Irvine, CA 92697 USA
| | - Daniel Gillen
- Institute for Brain Aging and Dementia, University of California, Irvine, CA 92697 USA
- Department of Statistics, University of California, Irvine, CA 92697 USA
| | - Clifford Anderson-Bergman
- Institute for Brain Aging and Dementia, University of California, Irvine, CA 92697 USA
- Department of Statistics, University of California, Irvine, CA 92697 USA
| | - David H. Cribbs
- Institute for Brain Aging and Dementia, University of California, Irvine, CA 92697 USA
- Department of Neurology, University of California, Irvine, CA 92697 USA
| | - Charles Glabe
- Institute for Brain Aging and Dementia, University of California, Irvine, CA 92697 USA
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697 USA
| | - Elizabeth Head
- Institute for Brain Aging and Dementia, University of California, Irvine, CA 92697 USA
- Department of Neurology, University of California, Irvine, CA 92697 USA
- Department of Molecular and Biomedical Pharmacology, Sanders-Brown Center on Aging, University of Kentucky, 203 Sanders-Brown Building, 800 South Limestone Street, Lexington, KY 40536 USA
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77
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Acero G, Manoutcharian K, Vasilevko V, Munguia ME, Govezensky T, Coronas G, Luz-Madrigal A, Cribbs DH, Gevorkian G. Immunodominant epitope and properties of pyroglutamate-modified Abeta-specific antibodies produced in rabbits. J Neuroimmunol 2009; 213:39-46. [PMID: 19545911 PMCID: PMC2725226 DOI: 10.1016/j.jneuroim.2009.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 05/29/2009] [Accepted: 06/02/2009] [Indexed: 02/06/2023]
Abstract
N-truncated and N-modified forms of amyloid beta (Abeta) peptide are found in diffused and dense core plaques in Alzheimer's disease (AD) and Down's syndrome patients as well as transgenic mouse models of AD. Although the pathological significance of these shortened forms Abeta is not completely understood, previous studies have demonstrated that these peptides are significantly more resistant to degradation, aggregate more rapidly in vitro and exhibit similar or, in some cases, increased toxicity in hippocampal neuronal cultures compared to the full length peptides. In the present study we further investigated the mechanisms of toxicity of one of the most abundant N-truncated/modified Abeta peptide bearing amino-terminal pyroglutamate at position 3 (AbetaN3(pE)). We demonstrated that AbetaN3(pE) oligomers induce phosphatidyl serine externalization and membrane damage in SH-SY5Y cells. Also, we produced AbetaN3(pE)-specific polyclonal antibodies in rabbit and identified an immunodominant epitope recognized by anti-AbetaN3(pE) antibodies. Our results are important for developing new immunotherapeutic compounds specifically targeting AbetaN3(pE) aggregates since the most commonly used immunogens in the majority of vaccines for AD have been shown to induce antibodies that recognize the N-terminal immunodominant epitope (EFRH) of the full length Abeta, which is absent in N-amino truncated peptides.
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Affiliation(s)
- G Acero
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), AP 70228, Cuidad Universitaria, México DF, 04510, Mexico
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78
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Kumar-Singh S. Hereditary and sporadic forms of abeta-cerebrovascular amyloidosis and relevant transgenic mouse models. Int J Mol Sci 2009; 10:1872-1895. [PMID: 19468344 PMCID: PMC2680652 DOI: 10.3390/ijms10041872] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 04/14/2009] [Accepted: 04/20/2009] [Indexed: 12/28/2022] Open
Abstract
Cerebral amyloid angiopathy (CAA) refers to the specific deposition of amyloid fibrils in the leptomeningeal and cerebral blood vessel walls, often causing secondary vascular degenerative changes. Although many kinds of peptides are known to be deposited as vascular amyloid, amyloid-beta (Abeta)-CAA is the most common type associated with normal aging, sporadic CAA, Alzheimer's disease (AD) and Down's syndrome. Moreover, Abeta-CAA is also associated with rare hereditary cerebrovascular amyloidosis due to mutations within the Abeta domain of the amyloid precursor protein (APP) such as Dutch and Flemish APP mutations. Genetics and clinicopathological studies on these familial diseases as well as sporadic conditions have already shown that CAA not only causes haemorrhagic and ischemic strokes, but also leads to progressive dementia. Transgenic mouse models based on familial AD mutations have also successfully reproduced many of the features found in human disease, providing us with important insights into the pathogenesis of CAA. Importantly, such studies have pointed out that specific vastopic Abeta variants or an unaltered Abeta42/Abeta40 ratio favor vascular Abeta deposition over parenchymal plaques, but higher than critical levels of Abeta40 are also observed to be anti-amyloidogenic. These data would be important in the development of therapies targeting amyloid in vessels.
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Affiliation(s)
- Samir Kumar-Singh
- Neurodegenerative Brain Diseases Group, VIB Department of Molecular Genetics, University of Antwerp, Antwerpen - CDE, Universiteitsplein 1, B-2610, Antwerpen, Belgium; E-Mail:
; Tel. +3232651002; Fax: +3232651012
- Laboratory of Neurogenetics, Institute Born Bunge, University of Antwerp, Antwerpen, Belgium
- University of Antwerp, Antwerpen, Belgium
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79
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Boonen RA, van Tijn P, Zivkovic D. Wnt signaling in Alzheimer's disease: up or down, that is the question. Ageing Res Rev 2009; 8:71-82. [PMID: 19101658 DOI: 10.1016/j.arr.2008.11.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2008] [Revised: 11/26/2008] [Accepted: 11/26/2008] [Indexed: 12/27/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder, neuropathologically characterized by amyloid-beta (Abeta) plaques and hyperphosphorylated tau accumulation. AD occurs sporadically (SAD), or is caused by hereditary missense mutations in the amyloid precursor protein (APP) or presenilin-1 and -2 (PSEN1 and PSEN2) genes, leading to early-onset familial AD (FAD). Accumulating evidence points towards a role for altered Wnt/beta-catenin-dependent signaling in the etiology of both forms of AD. Presenilins are involved in modulating beta-catenin stability; therefore FAD-linked PSEN-mediated effects can deregulate the Wnt pathway. Genetic variations in the low-density lipoprotein receptor-related protein 6 and apolipoprotein E in AD have been associated with reduced Wnt signaling. In addition, tau phosphorylation is mediated by glycogen synthase kinase-3 (GSK-3), a key antagonist of the Wnt pathway. In this review, we discuss Wnt/beta-catenin signaling in both SAD and FAD, and recapitulate which of its aberrant functions may be critical for (F)AD pathogenesis. We discuss the intriguing possibility that Abeta toxicity may downregulate the Wnt/beta-catenin pathway, thereby upregulating GSK-3 and consequent tau hyperphosphorylation, linking Abeta and tangle pathology. The currently available evidence implies that disruption of tightly regulated Wnt signaling may constitute a key pathological event in AD. In this context, drug targets aimed at rescuing Wnt signaling may prove to be a constructive therapeutic strategy for AD.
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80
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Sevalle J, Amoyel A, Robert P, Fournié-Zaluski MC, Roques B, Checler F. Aminopeptidase A contributes to the N-terminal truncation of amyloid beta-peptide. J Neurochem 2009; 109:248-56. [PMID: 19187443 DOI: 10.1111/j.1471-4159.2009.05950.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Several lines of data previously indicated that N-terminally truncated forms of amyloid-beta (Abeta) peptides are likely the earliest and more abundant species immunohistochemically detectable in Alzheimer's disease-affected brains. It is noteworthy that the free N-terminal residue of full-length Abeta (fl-Abeta) is an aspartyl residue, suggesting that Abeta could be susceptible to exopeptidasic attack by aminopeptidase A (APA)-like proteases. In this context, we have examined whether APA could target Abeta peptides in both cell-free and cellular models. We first show that the general aminopeptidase inhibitor amastatin as well as two distinct aminopeptidase A inhibitors EC33 and pl302 both significantly increase the recovery of genuine fl-Abeta peptides generated by cells over-expressing Swedish-mutated beta amyloid precursor protein (APP) while the aminopeptidase N blocker pl250 did not modify fl-Abeta recovery. In agreement with this observation, we establish that over-expressed APA drastically reduces, in a calcium dependent manner, fl-Abeta but not APP IntraCellular Domain in a cell-free model of Abeta production. In agreement with the above data, we show that recombinant APA degrades fl-Abeta in a pl302-sensitive manner. Interestingly, we also show that EC33 and pl302 lower staurosporine-stimulated activation of caspase-3 in wild-type fibroblasts but not in betaAPP/beta-amyloid precursor protein-like protein 2 (APLP2) double knockout fibroblasts, suggesting that protecting endogenous fl-Abeta physiological production triggers neuroprotective phenotype. By contrast, EC33 does not modify staurosporine-induced caspase-3 activation in wild-type and Swedish-mutated betaAPP-HEK293 expressing cells that display exacerbated production of Abeta. Overall, our data establish that APA contributes to the N-terminal truncation of Abeta and suggest that this cleavage is likely abrogating a protective function associated with physiological but not supraphysiological levels of genuine fl-Abeta peptides.
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Affiliation(s)
- Jean Sevalle
- Institut de Pharmacologie Moléculaire et Cellulaire and Institut de NeuroMédecine Moléculaire, UMR6097 CNRS/UNSA, Equipe labellisée Fondation pour la Recherche Médicale, Sophia-Antipolis, Valbonne, France
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81
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Van Broeck B, Vanhoutte G, Cuijt I, Pereson S, Joris G, Timmermans JP, Van der Linden A, Van Broeckhoven C, Kumar-Singh S. Reduced brain volumes in mice expressing APP-Austrian mutation but not in mice expressing APP-Swedish-Austrian mutations. Neurosci Lett 2008; 447:143-7. [PMID: 18840503 DOI: 10.1016/j.neulet.2008.09.073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 09/09/2008] [Accepted: 09/17/2008] [Indexed: 11/19/2022]
Abstract
We previously described two transgenic mouse lines expressing sub-endogenous levels of the 'Austrian' APP-T714I mutation (driven by the prenatally active PDGF-beta promoter; APP-Au mice) and showing intraneuronal Abeta pathology and reduced brain volumes on MRI at 12 and 20 months of age. To further investigate whether reduced brain sizes were caused by neurodegeneration or a neurodevelopmental defect, we now measured brain volumes as early as postnatal day 10. At this age, a distinguishable reduction in brain volumes was absent, indicating that brain volume deficits in APP-Au mice are not caused by a neurodevelopmental defect. To further study the association between intraneuronal Abeta and reduced brain volumes, we further generated and analyzed an APP transgenic mouse model expressing both Austrian and Swedish (K670N/M671L) mutations (APP-SwAu mice). APP-Swedish mutation is known to lead to altered APP processing in the secretory pathway, precluding its later processing in endosomal-lysosomal compartments, the site of intraneuronal Abeta accumulation. Also, to have higher levels of transgene expression only after birth, a murine Thy-1 promoter was utilized for APP-SwAu mouse lines. Despite having five times higher transgene APP levels compared to APP-Au mice, APP-SwAu mice showed significantly lower intraneuronal Abeta levels in the absence of reduced brain volumes, suggesting that intraneuronal Abeta accumulation is related to reduced brain volumes in APP-Au mice. These data also provide a first in vivo indication of altered processing of APP-Swedish at sub-endogenous levels, an effect not observed in mouse models expressing the APP-Swedish mutation in high amounts.
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Affiliation(s)
- Bianca Van Broeck
- Neurodegenerative Brain Diseases Group, Department of Molecular Genetics, VIB, Antwerpen, Belgium
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82
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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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83
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Gorman PM, Kim S, Guo M, Melnyk RA, McLaurin J, Fraser PE, Bowie JU, Chakrabartty A. Dimerization of the transmembrane domain of amyloid precursor proteins and familial Alzheimer's disease mutants. BMC Neurosci 2008; 9:17. [PMID: 18234110 PMCID: PMC2266763 DOI: 10.1186/1471-2202-9-17] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Accepted: 01/30/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Amyloid precursor protein (APP) is enzymatically cleaved by gamma-secretase to form two peptide products, either Abeta40 or the more neurotoxic Abeta42. The Abeta42/40 ratio is increased in many cases of familial Alzheimer's disease (FAD). The transmembrane domain (TM) of APP contains the known dimerization motif GXXXA. We have investigated the dimerization of both wild type and FAD mutant APP transmembrane domains. RESULTS Using synthetic peptides derived from the APP-TM domain, we show that this segment is capable of forming stable transmembrane dimers. A model of a dimeric APP-TM domain reveals a putative dimerization interface, and interestingly, majority of FAD mutations in APP are localized to this interface region. We find that FAD-APP mutations destabilize the APP-TM dimer and increase the population of APP peptide monomers. CONCLUSION The dissociation constants are correlated to both the Abeta42/Abeta40 ratio and the mean age of disease onset in AD patients. We also show that these TM-peptides reduce Abeta production and Abeta42/Abeta40 ratios when added to HEK293 cells overexpressing the Swedish FAD mutation and gamma-secretase components, potentially revealing a new class of gamma-secretase inhibitors.
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Affiliation(s)
- Paul M Gorman
- Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Toronto, Ontario, M5G 2M9, Canada.
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84
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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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85
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Filley CM, Rollins YD, Anderson CA, Arciniegas DB, Howard KL, Murrell JR, Boyer PJ, Kleinschmidt-DeMasters BK, Ghetti B. The Genetics of Very Early Onset Alzheimer Disease. Cogn Behav Neurol 2007; 20:149-56. [PMID: 17846513 DOI: 10.1097/wnn.0b013e318145a8c8] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE This study was undertaken to clarify the genetics of very early onset Alzheimer disease (VEOAD), defined as AD beginning before age 35. BACKGROUND Early onset AD (EOAD) is defined by onset of symptoms before age 65, and affected individuals may harbor a mutation in presenilin 1 (PSEN1), presenilin 2 (PSEN2), or amyloid precursor protein. VEOAD is exceedingly rare, and PSEN1 mutations have been implicated. We encountered a man with phenotypic frontotemporal dementia beginning at age 32 and a strong family history of an autosomal dominant dementia who was found at autopsy to have AD. METHODS Histologic and genetic analyses of the patient's brain were undertaken, and a review of all published VEOAD cases was performed. RESULTS Histologic findings were diagnostic of advanced stage AD. Genetic evaluation of brain tissue identified an intronic PSEN1 polymorphism; no known pathogenic mutation was found. Literature review (1934 to 2007) disclosed 101 cases of VEOAD; the youngest age of dementia onset was 24 years. In all cases in which definitive genetic analysis was available, either a PSEN1 mutation or linkage to chromosome 14 was found. CONCLUSIONS VEOAD can present with atypical clinical features, including findings suggestive of frontotemporal dementia. All reported cases of VEOAD with conclusive genetic analysis seem to be associated with PSEN1 mutations. Genetic testing in adults younger than 35 with dementia can identify the genetic defect and assist in diagnosis and family counseling.
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Affiliation(s)
- Christopher M Filley
- Department of Neurology, University of Colorado School of Medicine, Denver, CO, USA.
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86
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Van Broeck B, Van Broeckhoven C, Kumar-Singh S. Current insights into molecular mechanisms of Alzheimer disease and their implications for therapeutic approaches. NEURODEGENER DIS 2007; 4:349-65. [PMID: 17622778 DOI: 10.1159/000105156] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Accepted: 12/12/2006] [Indexed: 01/13/2023] Open
Abstract
During the last 10 years, a lot of progress has been made in unraveling the pathogenic cascade leading to Alzheimer disease (AD). According to the most widely accepted hypothesis, production and aggregation of the amyloid beta (Abeta) peptide plays a key role in AD, and thus therapeutic interference with these processes is the subject of intense research. However, some important aspects of the disease mechanism are not yet fully understood. There is no consensus as yet on whether the disease acts through a loss- (LOF) or a gain-of-function (GOF) mechanism. While for many years, an increased production of Abeta42 was considered to be the prime culprit for the initiation of the disease process, and accordingly Abeta42 is elevated by AD-related presenilin(PS) mutations, recent data strongly suggest that PS mutations also lead to a LOF of PS towards a plethora of its substrates including amyloid precursor protein. How this PS LOF, especially decreased Abeta40 secretion due to mutant PS, impacts on the disease pathogenesis is yet to be elucidated. Secondly, vascular abnormalities--frequently observed to co-occur with AD--might also play a critical role in the initiation and aggravation of AD pathology given that the elimination of Abeta through a vascular route is an important brain Abeta clearance mechanism and its failure leads to formation of vascular amyloidosis and dense-core plaques. In this review, we will first focus on the important issue of a LOF versus a GOF mechanism for AD due to mutant PS, as well as on the possible role of vascular damage and reduced perfusion in AD. Special emphasis will be given to some of the AD mouse models that have helped to gain insights into the disease mechanism. Secondly, considering these mechanistic insights, we will discuss some therapeutic strategies which are currently in clinical or preclinical trials for AD.
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Affiliation(s)
- Bianca Van Broeck
- Neurodegenerative Brain Diseases Group, Department of Molecular Genetics, VIB, University of Antwerp, Universiteitsplein I, BE-2610 Antwerp, Belgium
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87
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Van Broeck B, Vanhoutte G, Pirici D, Van Dam D, Wils H, Cuijt I, Vennekens K, Zabielski M, Michalik A, Theuns J, De Deyn PP, Van der Linden A, Van Broeckhoven C, Kumar-Singh S. Intraneuronal amyloid beta and reduced brain volume in a novel APP T714I mouse model for Alzheimer's disease. Neurobiol Aging 2006; 29:241-52. [PMID: 17112635 DOI: 10.1016/j.neurobiolaging.2006.10.016] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Revised: 09/18/2006] [Accepted: 10/04/2006] [Indexed: 11/30/2022]
Abstract
Transgenic mouse models of Alzheimer's disease (AD) expressing high levels of amyloid precursor protein (APP) with familial AD (FAD) mutations have proven to be extremely useful in understanding pathogenic processes of AD especially those that involve amyloidogenesis. We earlier described Austrian APP T714I pathology that leads to one of the earliest AD age-at-onsets with abundant intracellular and extracellular amyloid deposits in brain. The latter strikingly was non-fibrillar diffuse amyloid, composed of N-truncated A beta 42 in absence of A beta 40. In vitro, this mutation leads to one of the highest A beta 42/A beta 40 ratios among all FAD mutations. We generated an APP T714I transgenic mouse model that despite having 10 times lower transgene than endogenous murine APP deposited intraneuronal A beta in brain by 6 months of age. Accumulations increased with age, and this was paralleled by decreased brain sizes on volumetric MRI, compared to age-matched and similar transgene-expressing APP wild-type mice, although, with these levels of transgenic expression we did not detect neuronal loss or significant memory impairment. Immunohistochemical studies revealed that the majority of the intraneuronal A beta deposits colocalized with late endosomal markers, although some A beta inclusions were also positive for lysosomal and Golgi markers. These data support earlier observations of A beta accumulation in the endosomal-lysosomal pathway and the hypothesis that intraneuronal accumulation of A beta could be an important factor in the AD pathogenesis.
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Affiliation(s)
- Bianca Van Broeck
- Neurodegenerative Brain Diseases Group, Department of Molecular Genetics, VIB, Universiteitsplein 1, BE-2610 Antwerpen, Belgium
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88
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Theuns J, Marjaux E, Vandenbulcke M, Van Laere K, Kumar-Singh S, Bormans G, Brouwers N, Van den Broeck M, Vennekens K, Corsmit E, Cruts M, De Strooper B, Van Broeckhoven C, Vandenberghe R. Alzheimer dementia caused by a novel mutation located in the APP C-terminal intracytosolic fragment. Hum Mutat 2006; 27:888-96. [PMID: 16917905 DOI: 10.1002/humu.20402] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Since the first report showing that Alzheimer disease (AD) might be caused by mutations in the amyloid precursor protein gene (APP), 20 different missense mutations have been reported. The majority of early-onset AD mutations alter processing of APP increasing relative levels of Abeta42 peptide, either by increasing Abeta42 or decreasing Abeta40 peptide levels or both. In a diagnostic setting using direct sequence analysis, we identified in one patient with familial early-onset AD a novel mutation in APP (c.2172G>C), predicting a K724N substitution in the intracytosolic fragment. The mutation is located downstream of the epsilon-cleavage site of APP and is the furthermost C-terminal mutation reported to date. In vitro expression of APP K724N cDNA showed an increase in Abeta42 and a decrease in Abeta40 levels resulting in a near three-fold increase of the Abeta42/Abeta40 ratio. Further, in vivo amyloid positron emission tomography (PET) imaging revealed significantly increased cortical amyloid deposits, supporting that in human this novel APP mutation is likely causing disease.
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Affiliation(s)
- J Theuns
- Neurodegenerative Brain Diseases Group, Department of Molecular Genetics, Flanders Interuniversity Institute for Biotechnology, Belgium
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89
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Kumar-Singh S, Theuns J, Van Broeck B, Pirici D, Vennekens K, Corsmit E, Cruts M, Dermaut B, Wang R, Van Broeckhoven C. Mean age-of-onset of familial alzheimer disease caused by presenilin mutations correlates with both increased Abeta42 and decreased Abeta40. Hum Mutat 2006; 27:686-95. [PMID: 16752394 DOI: 10.1002/humu.20336] [Citation(s) in RCA: 236] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The varied ways in which mutations in presenilins (PSEN1 and PSEN2) affect amyloid b precursor protein (APP) processing in causing early-onset familial Alzheimer disease (FAD) are complex and not yet properly understood. Nonetheless, one useful diagnostic marker is an increased ratio of Ab42 to Ab40 (Ab42/Ab40) in patients' brain and biological fluids as well as in transgenic mice and cells. We studied Ab and APP processing for a set of nine clinical PSEN mutations on a novel and highly reproducible enzyme-linked immunosorbent assay (ELISA)-based in vitro method and also sought correlation with brain Ab analyzed by image densitometry and mass spectrometry. All mutations significantly increased Ab42/Ab40 in vitro by significantly decreasing Ab40 with accumulation of APP C-terminal fragments, a sign of decreased PSEN activity. A significant increase in absolute levels of Ab42 was observed for only half of the mutations tested. We also showed that age-of-onset of PSEN1-linked FAD correlated inversely with Ab42/Ab40 (r = -0.89; P = 0.001) and absolute levels of Ab42 (r = -0.83; P = 0.006), but directly with Ab40 levels (r = 0.69; P = 0.035). These changes also partly correlated with brain Ab42 and Ab40 levels. Together, our data suggested that Ab40 might be protective by perhaps sequestering the more toxic Ab42 and facilitating its clearance. Also, the in vitro method we describe here is a valid tool for assaying the pathogenic potential of clinical PSEN mutations in a molecular diagnostic setting.
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Affiliation(s)
- Samir Kumar-Singh
- Neurodegenerative Brain Diseases Group, Department of Molecular Genetics, Flanders Interuniversity Institute of Biotechnology, University of Antwerp, Antwerpen, Belgium.
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Papassotiropoulos A, Fountoulakis M, Dunckley T, Stephan DA, Reiman EM. Genetics, transcriptomics, and proteomics of Alzheimer's disease. J Clin Psychiatry 2006; 67:652-70. [PMID: 16669732 PMCID: PMC2259384 DOI: 10.4088/jcp.v67n0418] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To provide an updated overview of the methods used in genetic, transcriptomic, and proteomic studies in Alzheimer's disease and to demonstrate the importance of those methods for the improvement of the current diagnostic and therapeutic possibilities. DATA SOURCES MEDLINE-based search of 233 peer-reviewed articles published between 1975 and 2006. DATA SYNTHESIS Alzheimer's disease is a genetically heterogeneous disorder. Rare mutations in the amyloid precursor protein, presenilin 1, and presenilin 2 genes have shown the importance of the amyloid metabolism for its development. In addition, converging evidence from population-based genetic studies, gene expression studies, and protein profile studies in the brain and in the cerebrospinal fluid suggest the existence of several pathogenetic pathways such as amyloid precursor protein processing, beta-amyloid degradation, tau phosphorylation, proteolysis, protein misfolding, neuroinflammation, oxidative stress, and lipid metabolism. CONCLUSIONS The development of high-throughput genotyping methods and of elaborated statistical analyses will contribute to the identification of genetic risk profiles related to the development and course of this devastating disease. The integration of knowledge derived from genetic, transcriptomic, and proteomic studies will greatly advance our understanding of the causes of Alzheimer's disease, improve our capability of establishing an early diagnosis, help define disease subgroups, and ultimately help to pave the road toward improved and tailored treatments.
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91
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Dermaut B, Kumar-Singh S, Rademakers R, Theuns J, Cruts M, Van Broeckhoven C. Tau is central in the genetic Alzheimer–frontotemporal dementia spectrum. Trends Genet 2005; 21:664-72. [PMID: 16221505 DOI: 10.1016/j.tig.2005.09.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Revised: 08/11/2005] [Accepted: 09/27/2005] [Indexed: 11/28/2022]
Abstract
In contrast to the common and genetically complex senile form of Alzheimer's disease (AD), the molecular genetic dissection of inherited presenile dementias has given important mechanistic insights into the pathogenesis of degenerative brain disease. Here, we focus on recent genotype-phenotype correlative studies in presenile AD and the frontotemporal dementia (FTD) complex of disorders. Together, these studies suggest that AD and FTD are linked in a genetic spectrum of presenile degenerative brain disorders in which tau appears to be the central player.
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Affiliation(s)
- Bart Dermaut
- Department of Molecular Genetics (VIB 8), Flanders Interuniversity Institute for Biotechnology, Neurodegenerative Brain Diseases Group, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, B-2610 Antwerpen, Belgium
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92
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Lindberg C, Selenica MLB, Westlind-Danielsson A, Schultzberg M. Beta-amyloid protein structure determines the nature of cytokine release from rat microglia. J Mol Neurosci 2005; 27:1-12. [PMID: 16055942 DOI: 10.1385/jmn:27:1:001] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Accepted: 01/22/2005] [Indexed: 12/18/2022]
Abstract
Activated microglia represent a major source of inflammatory factors in Alzheimer's disease and a possible source of cytotoxic factors. beta-Amyloid (Abeta) peptide, the predominant component in amyloid plaques, has been shown to activate microglia and stimulate their production of inflammatory factors. The present study was performed to analyze the responses of microglia to different forms of Abeta, with regard to release of the proinflammatory cytokines interleukin-1alpha (IL-1alpha), IL-1beta, tumor necrosis factor-alpha (TNF-alpha), IL-6, and interferon-gamma (IFN-gamma), as well as the IL-1 receptor antagonist (IL-1ra). Primary cultures of microglia from rat neonatal cerebral cortex were incubated with freshly dissolved Abeta1-40 or Abeta1-42, Abeta1-40 fibrils, Abeta1-40 betaamy balls, or vehicle. Abeta1-40 fibrils did not significantly stimulate any of these cytokines. Freshly dissolved Abeta1-40 resulted in a marked increase in the release of IL-1beta, and freshly dissolved Abeta1-42 significantly stimulated both IL-1alpha and IFN-gamma secretion. The Abeta1-40 betaamy balls stimulated the secretion of IL-1alpha and IL-1beta. Incubation with Abeta peptides did not affect the secretion of IL-1ra, IL-6, or TNF-alpha. In the case of IL-1beta, the response is correlated with the presence of Abeta peptide as monomers and oligomers.
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Affiliation(s)
- Catharina Lindberg
- Neurotec Department, Division of Experimental Geriatrics, Karolinska Institutet, Novum, SE-141 86 Stockholm, Sweden.
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93
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Schoonenboom NS, Mulder C, Van Kamp GJ, Mehta SP, Scheltens P, Blankenstein MA, Mehta PD. Amyloid beta 38, 40, and 42 species in cerebrospinal fluid: more of the same? Ann Neurol 2005; 58:139-42. [PMID: 15984010 DOI: 10.1002/ana.20508] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Various C-terminally truncated amyloid beta peptides (Abeta) are linked to Alzheimer's disease (AD) pathogenesis. Cerebrospinal fluid (CSF) concentrations of Abeta38, Abeta40, and Abeta42 were measured by enzyme-linked immunosorbent assay in 30 patients with AD and 26 control subjects. CSF Abeta42 levels was decreased in patients with AD, whereas CSF Abeta38 and Abeta40 levels were similar in patients with AD and control subjects. All three Abeta peptides were interrelated, particularly CSF Abeta38 and Abeta40. Diagnostic accuracy of CSF Abeta42 concentrations was not improved by applying the ratios of CSF Abeta42 to Abeta38 or Abeta40.
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Affiliation(s)
- Niki S Schoonenboom
- Alzheimer Center and Department of Neurology, VU University Medical Center, Amsterdam, the Netherlands.
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94
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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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95
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Crowther DC, Kinghorn KJ, Miranda E, Page R, Curry JA, Duthie FAI, Gubb DC, Lomas DA. Intraneuronal Aβ, non-amyloid aggregates and neurodegeneration in a Drosophila model of Alzheimer’s disease. Neuroscience 2005; 132:123-35. [PMID: 15780472 DOI: 10.1016/j.neuroscience.2004.12.025] [Citation(s) in RCA: 258] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2004] [Indexed: 11/18/2022]
Abstract
We have developed models of Alzheimer's disease in Drosophila melanogaster by expressing the Abeta peptides that accumulate in human disease. Expression of wild-type and Arctic mutant (Glu22Gly) Abeta(1-42) peptides in Drosophila neural tissue results in intracellular Abeta accumulation followed by non-amyloid aggregates that resemble diffuse plaques. These histological changes are associated with progressive locomotor deficits and vacuolation of the brain and premature death of the flies. The severity of the neurodegeneration is proportional to the propensity of the expressed Abeta peptide to form oligomers. The fly phenotype is rescued by treatment with Congo Red that reduces Abeta aggregation in vitro. Our model demonstrates that intracellular accumulation and non-amyloid aggregates of Abeta are sufficient to cause the neurodegeneration of Alzheimer's disease. Moreover it provides a platform to dissect the pathways of neurodegeneration in Alzheimer's disease and to develop novel therapeutic interventions.
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Affiliation(s)
- D C Crowther
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 2XY, UK.
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96
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97
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Willem M, Dewachter I, Smyth N, Van Dooren T, Borghgraef P, Haass C, Van Leuven F. beta-site amyloid precursor protein cleaving enzyme 1 increases amyloid deposition in brain parenchyma but reduces cerebrovascular amyloid angiopathy in aging BACE x APP[V717I] double-transgenic mice. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 165:1621-31. [PMID: 15509532 PMCID: PMC1618675 DOI: 10.1016/s0002-9440(10)63419-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The generation of amyloid peptides (Abeta) from the amyloid precursor protein (APP) is initiated by beta-secretase (BACE), whereas subsequent gamma-secretase cleavage mediated by presenilin-1, produces Abeta peptides mainly of 40 or 42 amino acids long. In addition, alternative beta'-cleavage of APP at position 11 of the amyloid sequence results in N-truncated Abeta(11-40/42) peptides, but the functional significance or pathological impact is unknown. Here we demonstrate that in the brain of BACE x APP[V717I] double-transgenic mice, amyloidogenic processing at both Asp1 and Glu11 is increased resulting in more and different Abeta species and APP C-terminal fragments. Pathologically, BACE significantly increased the number of diffuse and senile amyloid plaques in old double-transgenic mice. Unexpectedly, vascular amyloid deposition was dramatically lower in the same BACE x APP[V717I] double-transgenic mice, relative to sex- and age-matched APP[V717I] single-transgenic mice in the same genetic background. The tight inverse relation of vascular amyloid to the levels of the less soluble N-terminally truncated Abeta peptides is consistent with the hypothesis that vascular amyloid deposition depends on drainage of excess tissue Abeta. This provides biochemical evidence in vivo for the preferential contribution of N-truncated Abeta to parenchymal amyloid deposition in contrast to vascular amyloid pathology.
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Affiliation(s)
- Michael Willem
- Experimental Genetics Group, LEGT_EGG, K.U. Leuven, Campus Gasthuisberg O and N 06, B-3000, Leuven, Belgium
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98
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Hecimovic S, Wang J, Dolios G, Martinez M, Wang R, Goate AM. Mutations in APP have independent effects on Aβ and CTFγ generation. Neurobiol Dis 2004; 17:205-18. [PMID: 15474359 DOI: 10.1016/j.nbd.2004.04.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2003] [Revised: 04/02/2004] [Accepted: 04/15/2004] [Indexed: 11/26/2022] Open
Abstract
Understanding the molecular mechanism of beta-amyloid (Abeta) generation is crucial for Alzheimer's disease pathogenesis as well as for normal APP function. The transmembrane domain (TM) of APP appears to undergo presenilin-dependent gamma-secretase cleavage at two topologically distinct sites: a site in the middle of the TM domain that is crucial for the generation of Abeta-peptides, and a site close to the cytoplasmic border (S3-like/epsilon site) of the TM domain that leads to production of the APP intracellular domain (CTFgamma/AICD). We demonstrate that, in contrast to the unique effect of familial Alzheimer's disease (FAD) mutations in APP on Abeta42 production, some but not all FAD mutations also affect CTFgamma generation. Furthermore, changes in total CTFgamma levels do not correlate with either an increase or a decrease of any Abeta species, and inhibition of Abeta-peptide formation starting from position +1 (Abeta1-x) does not affect CTFgamma production. These results suggest that cleavage at the gamma40/42- and the S3-like sites can be dissociated, and that APP signaling and Abeta production are not tightly linked.
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Affiliation(s)
- Silva Hecimovic
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
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99
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Duyckaerts C. Looking for the link between plaques and tangles. Neurobiol Aging 2004; 25:735-9; discussion 743-6. [PMID: 15165696 DOI: 10.1016/j.neurobiolaging.2003.12.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2003] [Accepted: 12/10/2003] [Indexed: 11/16/2022]
Affiliation(s)
- Charles Duyckaerts
- Laboratoire de Neuropathologie Escourolle, Hôpital de La Salpêtrière, 47 Boulevard de l'Hôpital, 75651 Paris Cedex 13, France.
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100
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Bornebroek M, De Jonghe C, Haan J, Kumar-Singh S, Younkin S, Roos R, Van Broeckhoven C. Hereditary cerebral hemorrhage with amyloidosis Dutch type (AbetaPP 693): decreased plasma amyloid-beta 42 concentration. Neurobiol Dis 2004; 14:619-23. [PMID: 14678776 DOI: 10.1016/j.nbd.2003.08.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D) is a rare autosomal dominant disorder caused by an amyloid-beta precursor protein (AbetaPP) 693 mutation that clinically leads to recurrent hemorrhagic strokes and dementia. The disease is pathologically characterised by the deposition of Abeta in cerebral blood vessels and as plaques in the brain parenchyma. This study measured the Abeta40 and Abeta42 concentration in plasma of Dutch AbetaPP693 mutation carriers and controls. We found that the Abeta40 concentration was not different between AbetaPP693 mutation carriers and controls. However, the Abeta42 concentration was significantly decreased in the mutation carriers. No correlation exists between the APOE(epsilon)4 allele and the plasma of Abeta40 and Abeta42 levels in HCHWA-D patients. This finding contrasted with the increased concentrations found in Alzheimer's disease. Therefore it is suggested that the Dutch AbetaPP693 mutation located within the Abeta coding region of the AbetaPP gene has a different effect not only on clinical and pathological expression but also on Abeta processing.
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Affiliation(s)
- Marjolijn Bornebroek
- Department of Neurology K5Q, Leiden University Medical Center, P.O. Box 9600, 2300 RC, Leiden, The Netherlands.
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