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Volloch V, Olsen B, Rits S. Alzheimer's Disease is Driven by Intraneuronally Retained Beta-Amyloid Produced in the AD-Specific, βAPP-Independent Pathway: Current Perspective and Experimental Models for Tomorrow. ANNALS OF INTEGRATIVE MOLECULAR MEDICINE 2020; 2:90-114. [PMID: 32617536 PMCID: PMC7331974 DOI: 10.33597/aimm.02-1007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
A view of the origin and progression of Alzheimer's disease, AD, prevailing until now and formalized as the Amyloid Cascade Hypothesis theory, maintains that the disease is initiated by overproduction of beta-amyloid, Aβ, which is generated solely by the Aβ precursor protein, βAPP, proteolytic pathway and secreted from the cell. Consequent extracellular accumulation of Aβ triggers a cascade of molecular and cellular events leading to neurodegeneration that starts early in life, progresses as one prolonged process, builds up for decades, and culminates in symptomatic manifestations of the disease late in life. In this paradigm, a time window for commencement of therapeutic intervention is small and accessible only early in life. The outlook introduced in the present study is fundamentally different. It posits that the βAPP proteolytic/secretory pathway of Aβ production causes AD in humans no more than it does in either short- or long-lived non-human mammals that share this pathway with humans, accumulate beta-amyloid as they age, but do not develop the disease. Alzheimer's disease, according to this outlook, is driven by an additional powerful AD-specific pathway of Aβ production that operates in affected humans, is completely independent of the βAPP precursor, and is not available in non-human mammals. The role of the βAPP proteolytic pathway in the disease in humans is activation of this additional AD-specific Aβ production pathway. This occurs through accumulation of intracellular Aβ, primarily via ApoE-assisted cellular uptake of secreted beta-amyloid, but also through retention of a fraction of Aβ produced in the βAPP proteolytic pathway. With time, accumulated intracellular Aβ triggers mitochondrial dysfunction. In turn, cellular stresses associated with mitochondrial dysfunction, including ER stress, activate a second, AD-specific, Aβ production pathway: Asymmetric RNA-dependent βAPP mRNA amplification; animal βAPP mRNA is ineligible for this process. In this pathway, every conventionally produced βAPP mRNA molecule serves potentially as a template for production of severely 5'-truncated mRNA encoding not the βAPP but its C99 fragment (hence "asymmetric"), the immediate precursor of Aβ. Thus produced, N-terminal signal peptide-lacking C99 is processed not in the secretory pathway on the plasma membrane, but at the intracellular membrane sites, apparently in a neuron-specific manner. The resulting Aβ is, therefore, not secreted but is retained intraneuronally and accumulates rapidly within the cell. Increased levels of intracellular Aβ augment mitochondrial dysfunction, which, in turn, sustains the activity of the βAPP mRNA amplification pathway. These self-propagating mutual Aβ overproduction/mitochondrial dysfunction feedback cycles constitute a formidable two-stroke engine, an engine that drives Alzheimer's disease. The present outlook envisions Alzheimer's disorder as a two-stage disease. The first stage is a slow process of intracellular beta-amyloid accumulation. It results neither in significant neurodegenerative damage, nor in manifestation of the disease. The second stage commences with the activation of the βAPP mRNA amplification pathway shortly before symptomatic onset of the disease, sharply increases the rate of Aβ generation and the extent of its intraneuronal accumulation, produces significant damages, triggers AD symptoms, and is fast. In this paradigm, the time window of therapeutic intervention is wide open, and preventive treatment can be initiated any time, even late in life, prior to commencement of the second stage of the disease. Moreover, there are good reasons to believe that with a drug blocking the βAPP mRNA amplification pathway, it would be possible not only to preempt the disease but also to stop and to reverse it even when early AD symptoms have already manifested. There are numerous experimental models of AD, all based on a notion of the exceptionality of βAPP proteolytic/secretory pathway in Aβ production in the disease. However, with no drug even remotely effective in Alzheimer's disease, a long list of candidate drugs that succeeded remarkably in animal models, yet failed utterly in human clinical trials of potential AD drugs, attests to the inadequacy of currently employed AD models. The concept of a renewable supply of beta-amyloid, produced in the βAPP mRNA amplification pathway and retained intraneuronally in Alzheimer's disease, explains spectacular failures of both BACE inhibition and Aβ-immunotherapy in human clinical trials. This concept also forms the basis of a new generation of animal and cell-based experimental models of AD, described in the present study. These models incorporate Aβ- or C99-encoding mRNA amplification pathways of Aβ production, as well as intracellular retention of their product, and can support not only further investigation of molecular mechanisms of AD but also screening for and testing of candidate drugs aimed at therapeutic targets suggested by the present study.
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Affiliation(s)
- Vladimir Volloch
- Department of Developmental Biology, Harvard School of Dental Medicine, USA
| | - Bjorn Olsen
- Department of Developmental Biology, Harvard School of Dental Medicine, USA
| | - Sophia Rits
- Division of Molecular Medicine, Children’s Hospital, Boston, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, USA
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2
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Abstract
Amyloid precursor A4 (770 amino acids (aa)) dimerizes and aggregates, as do its C-terminal (99 aa) and amyloid Aβ (40,42 aa Aβ40,Aβ42) fragments. The titled question has been discussed extensively, and here it is addressed further using thermodynamic scaling theory to analyze mutational trends in structural factors and kinetics. Special attention is given to Family Alzheimer's disease mutations in C99 outside Aβ42 centered on Aβ46. The scaling analysis is connected to extensive C99 docking simulations which included membranes ( Sun et al. J. Chem. Inf. Model. 2017 , 57 , 1375 - 1387 ), thereby confirming their C99 results and extending them to A4.
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Affiliation(s)
- James C. Phillips
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, United States
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3
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Bi C, Bi S, Li B. Processing of Mutant β-Amyloid Precursor Protein and the Clinicopathological Features of Familial Alzheimer's Disease. Aging Dis 2019; 10:383-403. [PMID: 31011484 PMCID: PMC6457050 DOI: 10.14336/ad.2018.0425] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 04/25/2018] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is a complex, multifactorial disease involving many pathological mechanisms. Nonetheless, single pathogenic mutations in amyloid precursor protein (APP) or presenilin 1 or 2 can cause AD with almost all of the clinical and neuropathological features, and therefore, we believe an important mechanism of pathogenesis in AD could be revealed from examining pathogenic APP missense mutations. A comprehensive review of the literature, including clinical, neuropathological, cellular and animal model data, was conducted through PubMed and the databases of Alzforum mutations, HGMD, UniProt, and AD&FTDMDB. Pearson correlation analysis combining the clinical and neuropathological data and aspects of mutant APP processing in cellular models was performed. We find that an increase in Aβ42 has a significant positive correlation with the appearance of neurofibrillary tangles (NFTs) and tends to cause an earlier age of AD onset, while an increase in Aβ40 significantly increases the age at death. The increase in the α-carboxyl terminal fragment (CTF) has a significantly negative correlation with the age of AD onset, and β-CTF has a similar effect without statistical significance. Animal models show that intracellular Aβ is critical for memory defects. Based on these results and the fact that amyloid plaque burden correlates much less well with cognitive impairment than do NFT counts, we propose a "snowball hypothesis": the accumulation of intraneuronal NFTs caused by extracellular Aβ42 and the increase in intraneuronal APP proteolytic products (CTFs and Aβs) could cause cellular organelle stress that leads to neurodegeneration in AD, which then resembles the formation of abnormal protein "snowballs" both inside and outside of neurons.
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Affiliation(s)
- Christopher Bi
- Washington Institute for Health Sciences, Arlington, VA 22203, USA
| | - Stephanie Bi
- Washington Institute for Health Sciences, Arlington, VA 22203, USA
| | - Bin Li
- Washington Institute for Health Sciences, Arlington, VA 22203, USA
- Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington DC 20057, USA
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4
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Chen W, Gamache E, Rosenman DJ, Xie J, Lopez MM, Li YM, Wang C. Familial Alzheimer's mutations within APPTM increase Aβ42 production by enhancing accessibility of ε-cleavage site. Nat Commun 2015; 5:3037. [PMID: 24390130 DOI: 10.1038/ncomms4037] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 11/29/2013] [Indexed: 02/08/2023] Open
Abstract
The high Aβ42/Aβ40 production ratio is a hallmark of familial Alzheimer's disease, which can be caused by mutations in the amyloid precursor protein (APP). The C-terminus of Aβ is generated by γ-secretase cleavage within the transmembrane domain of APP (APPTM), a process that is primed by an initial ε-cleavage at either T48 or L49, resulting in subsequent production of Aβ42 or Aβ40, respectively. Here we solve the dimer structures of wild-type APPTM (AAPTM WT) and mutant APPTM (FAD mutants V44M) with solution NMR. The right-handed APPTM helical dimer is mediated by GXXXA motif. From the NMR structural and dynamic data, we show that the V44M and V44A mutations can selectively expose the T48 site by weakening helical hydrogen bonds and increasing hydrogen-deuterium exchange rate (kex). We propose a structural model in which FAD mutations (V44M and V44A) can open the T48 site γ-secretase for the initial ε-cleavage, and consequently shift cleavage preference towards Aβ42.
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Affiliation(s)
- Wen Chen
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
| | - Eric Gamache
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
| | - David J Rosenman
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
| | - Jian Xie
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
| | - Maria M Lopez
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
| | - Yue-Ming Li
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York 10065, USA
| | - Chunyu Wang
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180, USA
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5
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Hubin E, Deroo S, Schierle GK, Kaminski C, Serpell L, Subramaniam V, van Nuland N, Broersen K, Raussens V, Sarroukh R. Two distinct β-sheet structures in Italian-mutant amyloid-beta fibrils: a potential link to different clinical phenotypes. Cell Mol Life Sci 2015; 72:4899-913. [PMID: 26190022 PMCID: PMC4648968 DOI: 10.1007/s00018-015-1983-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 06/06/2015] [Accepted: 07/02/2015] [Indexed: 12/22/2022]
Abstract
Most Alzheimer’s disease (AD) cases are late-onset and characterized by the aggregation and deposition of the amyloid-beta (Aβ) peptide in extracellular plaques in the brain. However, a few rare and hereditary Aβ mutations, such as the Italian Glu22-to-Lys (E22K) mutation, guarantee the development of early-onset familial AD. This type of AD is associated with a younger age at disease onset, increased β-amyloid accumulation, and Aβ deposition in cerebral blood vessel walls, giving rise to cerebral amyloid angiopathy (CAA). It remains largely unknown how the Italian mutation results in the clinical phenotype that is characteristic of CAA. We therefore investigated how this single point mutation may affect the aggregation of Aβ1–42 in vitro and structurally characterized the resulting fibrils using a biophysical approach. This paper reports that wild-type and Italian-mutant Aβ both form fibrils characterized by the cross-β architecture, but with distinct β-sheet organizations, resulting in differences in thioflavin T fluorescence and solvent accessibility. E22K Aβ1–42 oligomers and fibrils both display an antiparallel β-sheet structure, in comparison with the parallel β-sheet structure of wild-type fibrils, characteristic of most amyloid fibrils described in the literature. Moreover, we demonstrate structural plasticity for Italian-mutant Aβ fibrils in a pH-dependent manner, in terms of their underlying β-sheet arrangement. These findings are of interest in the ongoing debate that (1) antiparallel β-sheet structure might represent a signature for toxicity, which could explain the higher toxicity reported for the Italian mutant, and that (2) fibril polymorphism might underlie differences in disease pathology and clinical manifestation.
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Affiliation(s)
- Ellen Hubin
- Nanobiophysics Group, Faculty of Science and Technology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, 7500 AE, Enschede, The Netherlands.,Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium.,Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium
| | - Stéphanie Deroo
- Laboratory of Structure and Function of Biological Membrane, Faculté des Sciences, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles (ULB), Campus de la Plaine CP 206/02, Boulevard du Triomphe, 1050, Brussels, Belgium
| | - Gabriele Kaminksi Schierle
- Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge, CB2 3RA, UK
| | - Clemens Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge, CB2 3RA, UK
| | - Louise Serpell
- School of Life Sciences, University of Sussex, Falmer, East Sussex, BN1 9QG, UK
| | - Vinod Subramaniam
- Nanobiophysics Group, Faculty of Science and Technology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, 7500 AE, Enschede, The Netherlands.,FOM Institute AMOLF, Science Park 104, 1098 XG, Amsterdam, The Netherlands
| | - Nico van Nuland
- Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium.,Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium
| | - Kerensa Broersen
- Nanobiophysics Group, Faculty of Science and Technology, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, 7500 AE, Enschede, The Netherlands.
| | - Vincent Raussens
- Laboratory of Structure and Function of Biological Membrane, Faculté des Sciences, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles (ULB), Campus de la Plaine CP 206/02, Boulevard du Triomphe, 1050, Brussels, Belgium
| | - Rabia Sarroukh
- Laboratory of Structure and Function of Biological Membrane, Faculté des Sciences, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles (ULB), Campus de la Plaine CP 206/02, Boulevard du Triomphe, 1050, Brussels, Belgium.
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6
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García-Ayllón MS, Campanari ML, Montenegro MF, Cuchillo-Ibáñez I, Belbin O, Lleó A, Tsim K, Vidal CJ, Sáez-Valero J. Presenilin-1 influences processing of the acetylcholinesterase membrane anchor PRiMA. Neurobiol Aging 2014; 35:1526-36. [PMID: 24612677 DOI: 10.1016/j.neurobiolaging.2014.01.147] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Revised: 01/26/2014] [Accepted: 01/30/2014] [Indexed: 01/13/2023]
Abstract
Presenilin-1 (PS1) is the catalytic component of the γ-secretase complex. In this study, we explore if PS1 participates in the processing of the cholinergic acetylcholinesterase (AChE). The major AChE variant expressed in the brain is a tetramer (G(4)) bound to a proline-rich membrane anchor (PRiMA). Overexpression of the transmembrane PRiMA protein in Chinese hamster ovary cells expressing AChE and treated with the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester have enabled us to study whether, through its γ-secretase activity, PS1 participates in the processing of PRiMA-linked AChE. γ-Secretase inhibition led to a notable increase in the level of PRiMA-linked AChE, suggesting that γ-secretase is involved in the cleavage of PRiMA. We demonstrate that cleavage of PRiMA by γ-secretase results in a C-terminal PRiMA fragment. Immunofluorescence labeling allowed us to identify this PRiMA fragment in the nucleus. Moreover, we have determined changes in the proportion of the raft-residing AChE-PRiMA in a PS1 conditional knockout mouse. Our results are of interest as both enzymes have therapeutic relevance for Alzheimer's disease.
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Affiliation(s)
- María-Salud García-Ayllón
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Sant Joan d'Alacant, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Unidad de Investigación, Hospital General Universitario de Elche, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana (FISABIO), Elche, Spain
| | - María-Letizia Campanari
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Sant Joan d'Alacant, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - María-Fernanda Montenegro
- Departamento de Bioquímica y Biología Molecular-A, Universidad de Murcia, Regional Campus of International Excellence "Campus Mare Nostrum", Murcia, Spain
| | - Inmaculada Cuchillo-Ibáñez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Sant Joan d'Alacant, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Olivia Belbin
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Memory Unit, Neurology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Alberto Lleó
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Memory Unit, Neurology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Karl Tsim
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Cecilio J Vidal
- Departamento de Bioquímica y Biología Molecular-A, Universidad de Murcia, Regional Campus of International Excellence "Campus Mare Nostrum", Murcia, Spain
| | - Javier Sáez-Valero
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Sant Joan d'Alacant, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
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7
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Findeis MA, Schroeder F, McKee TD, Yager D, Fraering PC, Creaser SP, Austin WF, Clardy J, Wang R, Selkoe D, Eckman CB. Discovery of a novel pharmacological and structural class of gamma secretase modulators derived from the extract of Actaea racemosa. ACS Chem Neurosci 2012. [PMID: 23205187 DOI: 10.1021/cn3000857] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
A screen of a library of synthetic drugs and natural product extracts identified a botanical extract that modulates the processing of amyloid precursor protein (APP) in cultured cells to produce a lowered ratio of amyloid-beta peptide (1-42) (Aβ42) relative to Aβ40. This profile is of interest as a potential treatment for Alzheimer's disease. The extract, from the black cohosh plant (Actaea racemosa), was subjected to bioassay guided fractionation to isolate active components. Using a combination of normal-phase and reverse-phase chromatography, a novel triterpene monoglycoside, 1, was isolated. This compound was found to have an IC(50) of 100 nM for selectively reducing the production of amyloidogenic Aβ42 while having a much smaller effect on the production of Aβ40 (IC(50) 6.3 μM) in cultured cells overexpressing APP. Using IP-MS methods, this compound was found to modulate the pool of total Aβ produced by reducing the proportion of Aβ42 while increasing the relative amounts of shorter and less amyloidogenic Aβ37 and Aβ39. Concentrations of 1 sufficient to lower levels of Aβ42 substantially (up to 10 μM) did not significantly affect the processing of Notch or other aspects of APP processing. When 1 (10 μg) was administered to CD-1 normal mice intracerebroventricularly, the level of Aβ42 in brain was reduced. Assays for off-target pharmacology and the absence of overt signs of toxicity in mice dosed with compound 1 suggest a comparatively selective pharmacology for this triterpenoid. Compound 1 represents a new lead for the development of potential treatments for Alzheimer's disease via modulation of gamma-secretase.
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Affiliation(s)
- Mark A. Findeis
- Satori Pharmaceuticals, Incorporated, Cambridge, Massachusetts, United States
| | - Frank Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, United States
| | - Timothy D. McKee
- Satori Pharmaceuticals, Incorporated, Cambridge, Massachusetts, United States
| | - Debra Yager
- Mayo Clinic, Jacksonville, Florida, United States
| | - Patrick C. Fraering
- Harvard Medical School, Center for Neurologic Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States
| | - Steffen P. Creaser
- Satori Pharmaceuticals, Incorporated, Cambridge, Massachusetts, United States
| | - Wesley F. Austin
- Satori Pharmaceuticals, Incorporated, Cambridge, Massachusetts, United States
| | - Jon Clardy
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States
| | - Rong Wang
- Department of Genetics and Genomic Science, Mount Sinai School of Medicine, New York, New York, United States
| | - Dennis Selkoe
- Harvard Medical School, Center for Neurologic Diseases, Brigham & Women’s Hospital, Boston, Massachusetts, United States
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8
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Chen WT, Hong CJ, Lin YT, Chang WH, Huang HT, Liao JY, Chang YJ, Hsieh YF, Cheng CY, Liu HC, Chen YR, Cheng IH. Amyloid-beta (Aβ) D7H mutation increases oligomeric Aβ42 and alters properties of Aβ-zinc/copper assemblies. PLoS One 2012; 7:e35807. [PMID: 22558227 PMCID: PMC3340413 DOI: 10.1371/journal.pone.0035807] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 03/22/2012] [Indexed: 12/13/2022] Open
Abstract
Amyloid precursor protein (APP) mutations associated with familial Alzheimer's disease (AD) usually lead to increases in amyloid β-protein (Aβ) levels or aggregation. Here, we identified a novel APP mutation, located within the Aβ sequence (AβD7H), in a Taiwanese family with early onset AD and explored the pathogenicity of this mutation. Cellular and biochemical analysis reveal that this mutation increased Aβ production, Aβ42/40 ratio and prolonged Aβ42 oligomer state with higher neurotoxicity. Because the D7H mutant Aβ has an additional metal ion-coordinating residue, histidine, we speculate that this mutation may promote susceptibility of Aβ to ion. When co-incubated with Zn2+ or Cu2+, AβD7H aggregated into low molecular weight oligomers. Together, the D7H mutation could contribute to AD pathology through a “double punch” effect on elevating both Aβ production and oligomerization. Although the pathogenic nature of this mutation needs further confirmation, our findings suggest that the Aβ N-terminal region potentially modulates APP processing and Aβ aggregation, and further provides a genetic indication of the importance of Zn2+ and Cu2+ in the etiology of AD.
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Affiliation(s)
- Wei-Ting Chen
- Institute of Brain Science, National Yang Ming University, Taipei, Taiwan
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan
| | - Chen-Jee Hong
- Institute of Brain Science, National Yang Ming University, Taipei, Taiwan
- Division of Psychiatry, National Yang Ming University, Taipei, Taiwan
- Institute of Clinical Medicine, National Yang Ming University, Taipei, Taiwan
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Ya-Tzu Lin
- Institute of Brain Science, National Yang Ming University, Taipei, Taiwan
| | - Wen-Han Chang
- Institute of Brain Science, National Yang Ming University, Taipei, Taiwan
| | - He-Ting Huang
- Institute of Brain Science, National Yang Ming University, Taipei, Taiwan
| | - Jhih-Ying Liao
- Institute of Brain Science, National Yang Ming University, Taipei, Taiwan
| | - Yu-Jen Chang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Yi-Fang Hsieh
- Institute of Brain Science, National Yang Ming University, Taipei, Taiwan
| | - Chih-Ya Cheng
- Institute of Clinical Medicine, National Yang Ming University, Taipei, Taiwan
| | - Hsiu-Chih Liu
- Division of Neurology, National Yang Ming University, Taipei, Taiwan
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Yun-Ru Chen
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
- * E-mail: (IHC); (YRC)
| | - Irene H. Cheng
- Institute of Brain Science, National Yang Ming University, Taipei, Taiwan
- Brain Research Center, National Yang Ming University, Taipei, Taiwan
- * E-mail: (IHC); (YRC)
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9
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β-Secretases, Alzheimer's Disease, and Down Syndrome. Curr Gerontol Geriatr Res 2012; 2012:362839. [PMID: 22481915 PMCID: PMC3299320 DOI: 10.1155/2012/362839] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 12/05/2011] [Indexed: 01/01/2023] Open
Abstract
Individuals with Down Syndrome (DS), or trisomy 21, develop Alzheimer's disease (AD) pathology by approximately 40 years of age. Chromosome 21 harbors several genes implicated in AD, including the amyloid precursor protein and one homologue of the β-site APP cleaving enzyme, BACE2. Processing of the amyloid precursor protein by β-secretase (BACE) is the rate-limiting step in the production of the pathogenic Aβ peptide. Increased amounts of APP in the DS brain result in increased amounts of Aβ and extracellular plaque formation beginning early in life. BACE dysregulation potentially represents an overlapping biological mechanism with sporadic AD and a common therapeutic target. As the lifespan for those with DS continues to increase, age-related concerns such as obesity, depression, and AD are of growing concern. The ability to prevent or delay the progression of neurodegenerative diseases will promote healthy aging and improve quality of life for those with DS.
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10
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Quintero-Monzon O, Martin MM, Fernandez MA, Cappello CA, Krzysiak AJ, Osenkowski P, Wolfe MS. Dissociation between the processivity and total activity of γ-secretase: implications for the mechanism of Alzheimer's disease-causing presenilin mutations. Biochemistry 2011; 50:9023-35. [PMID: 21919498 PMCID: PMC3205908 DOI: 10.1021/bi2007146] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The amyloid β-peptide (Aβ), strongly implicated in the pathogenesis of Alzheimer's disease (AD), is produced from the amyloid β-protein precursor (APP) through consecutive proteolysis by β- and γ-secretases. The latter protease contains presenilin as the catalytic component of a membrane-embedded aspartyl protease complex. Missense mutations in presenilin are associated with early-onset familial AD, and these mutations generally both decrease Aβ production and increase the ratio of the aggregation-prone 42-residue form (Aβ42) to the 40-residue form (Aβ40). The connection between these two effects is not understood. Besides Aβ40 and Aβ42, γ-secretase produces a range of Aβ peptides, the result of initial cutting at the ε site to form Aβ48 or Aβ49 and subsequent trimming every three or four residues. Thus, γ-secretase displays both overall proteolytic activity (ε cutting) and processivity (trimming) toward its substrate APP. Here we tested whether a decrease in total activity correlates with decreased processivity using wild-type and AD-mutant presenilin-containing protease complexes. Changes in pH, temperature, and salt concentration that reduced the overall activity of the wild-type enzyme did not consistently result in increased proportions of longer Aβ peptides. Low salt concentrations and acidic pH were notable exceptions that subtly alter the proportion of individual Aβ peptides, suggesting that the charged state of certain residues may influence processivity. Five different AD mutant complexes, representing a broad range of effects on overall activity, Aβ42:Aβ40 ratios, and ages of disease onset, were also tested, revealing again that changes in total activity and processivity can be dissociated. Factors that control initial proteolysis of APP at the ε site apparently differ significantly from factors affecting subsequent trimming and the distribution of Aβ peptides.
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Affiliation(s)
| | | | - Marty A. Fernandez
- Center for Neurologic Diseases, Harvard Medical School and Brigham and Women’s Hospital, 77 Avenue Louis Pasteur, Boston, Massachusetts, 02115, USA
| | - Christina A. Cappello
- Center for Neurologic Diseases, Harvard Medical School and Brigham and Women’s Hospital, 77 Avenue Louis Pasteur, Boston, Massachusetts, 02115, USA
| | - Amanda J. Krzysiak
- Center for Neurologic Diseases, Harvard Medical School and Brigham and Women’s Hospital, 77 Avenue Louis Pasteur, Boston, Massachusetts, 02115, USA
| | - Pamela Osenkowski
- Center for Neurologic Diseases, Harvard Medical School and Brigham and Women’s Hospital, 77 Avenue Louis Pasteur, Boston, Massachusetts, 02115, USA
| | - Michael S. Wolfe
- Center for Neurologic Diseases, Harvard Medical School and Brigham and Women’s Hospital, 77 Avenue Louis Pasteur, Boston, Massachusetts, 02115, USA
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11
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Uemura K, Farner KC, Nasser-Ghodsi N, Jones P, Berezovska O. Reciprocal relationship between APP positioning relative to the membrane and PS1 conformation. Mol Neurodegener 2011; 6:15. [PMID: 21310068 PMCID: PMC3046905 DOI: 10.1186/1750-1326-6-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Accepted: 02/10/2011] [Indexed: 11/20/2022] Open
Abstract
Background Several familial Alzheimer disease (FAD) mutations within the transmembrane region of the amyloid precursor protein (APP) increase the Aβ42/40 ratio without increasing total Aβ production. In the present study, we analyzed the impact of FAD mutations and γ-secretase modulators (GSMs) that alter the Aβ42/40 ratio on APP C-terminus (CT) positioning relative to the membrane, reasoning that changes in the alignment of the APP intramembranous domain and presenilin 1 (PS1) may impact the PS1/γ-secretase cleavage site on APP. Results By using a Förster resonance energy transfer (FRET)-based technique, fluorescent lifetime imaging microscopy (FLIM), we show that Aβ42/40 ratio-modulating factors which target either APP substrate or PS1/γ-secretase affect proximity of the APP-CT to the membrane and change PS1 conformation. Conclusions Thus, we propose that there is a reciprocal relationship between APP-CT positioning relative to the membrane and PS1 conformation, suggesting that factors that modulate either APP positioning in the membrane or PS1 conformation could be exploited therapeutically.
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Affiliation(s)
- Kengo Uemura
- Alzheimer Research Unit, MassGeneral Institute for Neurodegenerative Diseases, Massachusetts General Hospital, Charlestown, MA 02129, USA.
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12
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Hsu MJ, Sheu JR, Lin CH, Shen MY, Hsu CY. Mitochondrial mechanisms in amyloid beta peptide-induced cerebrovascular degeneration. Biochim Biophys Acta Gen Subj 2010; 1800:290-6. [DOI: 10.1016/j.bbagen.2009.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 08/06/2009] [Accepted: 08/11/2009] [Indexed: 01/19/2023]
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13
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Tian Y, Bassit B, Chau D, Li YM. An APP inhibitory domain containing the Flemish mutation residue modulates gamma-secretase activity for Abeta production. Nat Struct Mol Biol 2010; 17:151-8. [PMID: 20062056 DOI: 10.1038/nsmb.1743] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Accepted: 11/17/2009] [Indexed: 11/09/2022]
Abstract
Gamma-secretase is an aspartyl protease that cleaves multiple substrates within their transmembrane domains. Gamma-secretase processes the amyloid precursor protein (APP) to generate gamma-amyloid (Agamma) peptides associated with Alzheimer's disease. Here, we show that APP possesses a substrate inhibitory domain (ASID) that negatively modulates gamma-secretase activity for Agamma production by binding to an allosteric site within the gamma-secretase complex. Alteration of this ASID by deletion or mutation, as is seen with the Flemish mutation (A21G), reduces its inhibitory potency and promotes Agamma production. Notably, peptides derived from ASID show selective inhibition of gamma-secretase activity for Agamma production over Notch1 processing. Therefore, this mode of regulation represents an unprecedented mechanism for modulating gamma-secretase, providing insight into the molecular basis of Alzheimer's disease pathogenesis and a potential strategy for the development of therapeutics.
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Affiliation(s)
- Yuan Tian
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
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14
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Tomita T. Peptides inhibiting specific cleaving activities of presenilins. Expert Opin Ther Pat 2008. [DOI: 10.1517/13543776.18.9.1097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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15
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Yin YI, Bassit B, Zhu L, Yang X, Wang C, Li YM. γ-Secretase Substrate Concentration Modulates the Aβ42/Aβ40 Ratio. J Biol Chem 2007; 282:23639-44. [PMID: 17556361 DOI: 10.1074/jbc.m704601200] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutation of the amyloid precursor protein (APP), presenilin-1, or presenilin-2 results in the development of early onset autosomal dominant forms of Alzheimer disease (AD). These mutations lead to an increased Abeta42/Abeta40 ratio that correlates with the onset of disease. However, it remains unknown how these mutations affect gamma-secretase, a protease that generates the termini of Abeta40 and Abeta42. Here we have determined the reaction mechanism of gamma-secretase with wild type and three mutated APP substrates. Our findings indicate that despite the overall outcome of an increased Abeta42/Abeta40 ratio, these mutations each display rather distinct reactivity to gamma-secretase. Intriguingly, we found that the ratio of Abeta42/Abeta40 is variable with substrate concentration; increased substrate concentrations result in higher ratios of Abeta42/Abeta40. Moreover, we demonstrated that reduction of gamma-secretase substrate concentration by BACE1 inhibition in cells decreased the Abeta42/Abeta40 ratio. This study indicates that biological factors affecting targets such as BACE1 and APP, which ultimately cause an increased concentration of gamma-secretase substrate, can augment the Abeta42/Abeta40 ratio and may play a causative role in sporadic AD. Therefore, strategies lowering the Abeta42/Abeta40 ratio through partial reduction of gamma-secretase substrate production may introduce a practical therapeutic modality for treatment of AD.
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Affiliation(s)
- Ye Ingrid Yin
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021 and Department of Biology, Rensselaer Polytechnic Institute, Troy, New York 12180
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16
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Abstract
The concept of disease in geriatric psychiatry has to keep up with the rapid expansion in knowledge about the putative etiology of various diseases of interest. This article reviews the new knowledge that has been acquired about dementia. The proposed classification system has two axes: one for clinical manifestations and the other for etiology. Implementing this nomenclature will allow rapid adaptation of new knowledge for causation while at the same time communicating information on the clinical state. This should improve our ability to incorporate and communicate new knowledge in a dynamic format. In turn, this strategy should improve our ability to discern particular features of a disease and refine our notion of its clinical presentation and lead toward novel and improved treatments for our patients.
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Affiliation(s)
- K Ranga Rama Krishnan
- Department of Psychiatry and Behavioral, Duke University Medical Center, Durham, NC 27710, USA.
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17
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Zhu S, Hsu AP, Vacek MM, Zheng L, Schäffer AA, Dale JK, Davis J, Fischer RE, Straus SE, Boruchov D, Saulsbury FT, Lenardo MJ, Puck JM. Genetic alterations in caspase-10 may be causative or protective in autoimmune lymphoproliferative syndrome. Hum Genet 2006; 119:284-94. [PMID: 16446975 DOI: 10.1007/s00439-006-0138-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2005] [Accepted: 01/04/2006] [Indexed: 11/26/2022]
Abstract
Autoimmune lymphoproliferative syndrome (ALPS) is characterized by lymphadenopathy, elevated numbers of T cells with alphabeta-T cell receptors but neither CD4 nor CD8 co-receptors, and impaired lymphocyte apoptosis in vitro. Defects in the Fas receptor are the most common cause of ALPS (ALPS Ia), but in rare cases other apoptosis proteins have been implicated, including caspase-10 (ALPS II). We investigated the role of variants of caspase-10 in ALPS. Of 32 unrelated probands with ALPS who did not have Fas defects, two were heterozygous for the caspase-10 missense mutation I406L. Like the previously reported ALPS II-associated mutation L285F, I406L impaired apoptosis when transfected alone and dominantly inhibited apoptosis mediated by wild type caspase-10 in a co-transfection assay. Other variants in caspase-10, V410I and Y446C, were found in 3.4 and 1.6% of chromosomes in Caucasians, and in 0.5 and <0.5% of African Americans, respectively. In contrast to L285F and I406L, these variants had no dominant negative effect in co-transfection assays into the H9 lymphocytic cell line. We found healthy individuals homozygous for V410I, challenging the earlier suggestion that homozygosity for V410I alone causes ALPS. Moreover, an association analysis suggested protection from severe disease by caspase-10 V410I in 63 families with ALPS Ia due to dominant Fas mutations (P<0.05). Thus, different genetic variations in caspase-10 can produce contrasting phenotypic effects.
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Affiliation(s)
- Shigui Zhu
- Genetics and Molecular Biology Branch, National Human Genome Research Institute, NIH, DHHS, Bethesda, MD 20892, USA
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18
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19
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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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20
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Abstract
Cerebral amyloid angiopathy (CAA) is the result of the deposition of an amyloidogenic protein in cortical and leptomeningeal vessels. The most common type of CAA is caused by amyloid beta-protein (Abeta), which is particularly associated with Alzheimer's disease (AD). Excessive Abeta-CAA formation can be caused by several mutations in the Abeta precursor protein and presenilin genes. The origin of Abeta in CAA is likely to be neuronal, although cerebrovascular cells or the circulation cannot be excluded as a source. Despite the apparent similarity, the pathogenesis of CAA appears to differ from that of senile plaques in several aspects, including the mechanism of Abeta-induced cellular toxicity, the extent of inflammatory reaction and the role of oxidative stress. Therefore, therapeutic strategies for AD should, at least in part, also target CAA. Moreover, CAA and cerebrovascular disease (CVD) may set a lower threshold for AD-like changes to cause dementia and may even cause dementia on its own, since patients with AD and CAA and/or CVD appear to be more cognitively impaired than patients with only AD. In conclusion, the precise impact of CAA on AD or dementia remains unclear, however, its role may have been underestimated in the past, and more extensive studies of in vitro and in vivo models for CAA will be needed to elucidate the importance of CAA-specific approaches in designing intervention strategies for AD.
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Affiliation(s)
- Annemieke A M Rensink
- Department of Neurology, Laboratory of Pediatrics and Neurology, University Medical Center, 319, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
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21
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Schroeter EH, Ilagan MXG, Brunkan AL, Hecimovic S, Li YM, Xu M, Lewis HD, Saxena MT, De Strooper B, Coonrod A, Tomita T, Iwatsubo T, Moore CL, Goate A, Wolfe MS, Shearman M, Kopan R. A presenilin dimer at the core of the gamma-secretase enzyme: insights from parallel analysis of Notch 1 and APP proteolysis. Proc Natl Acad Sci U S A 2003; 100:13075-80. [PMID: 14566063 PMCID: PMC240747 DOI: 10.1073/pnas.1735338100] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Notch receptors and the amyloid precursor protein are type I membrane proteins that are proteolytically cleaved within their transmembrane domains by a presenilin (PS)-dependent gamma-secretase activity. In both proteins, two peptide bonds are hydrolyzed: one near the inner leaflet and the other in the middle of the transmembrane domain. Under saturating conditions the substrates compete with each other for proteolysis, but not for binding to PS. At least some Alzheimer's disease-causing PS mutations reside in proteins possessing low catalytic activity. We demonstrate (i) that differentially tagged PS molecules coimmunoprecipitate, and (ii) that PS N-terminal fragment dimers exist by using a photoaffinity probe based on a transition state analog gamma-secretase inhibitor. We propose that gamma-secretase contains a PS dimer in its catalytic core, that binding of substrate is at a site separate from the active site, and that substrate is cleaved at the interface of two PS molecules.
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Affiliation(s)
- Eric H. Schroeter
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Ma. Xenia G. Ilagan
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Anne L. Brunkan
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Silva Hecimovic
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Yue-ming Li
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Min Xu
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Huw D. Lewis
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Meera T. Saxena
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Bart De Strooper
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Archie Coonrod
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Taisuke Tomita
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Takeshi Iwatsubo
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Chad L. Moore
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Alison Goate
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Michael S. Wolfe
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Mark Shearman
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
| | - Raphael Kopan
- Departments of Molecular Biology and Pharmacology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110; Department of Biological Chemistry, Merck Research Laboratories, West Point, PA 19486-0004; Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan; Department of Biochemistry and Molecular Biology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Harlow, Essex CM20 2QR, United Kingdom; Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115; Department of Pharmaceutical Sciences, University of Tennessee, Memphis, TN 38163; and Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Katholieke Universiteit and Flanders Interuniversity Institute for Biotechnology, VIB4 Leuven, Belgium
- To whom correspondence should be addressed. E-mail:
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22
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Morelli L, Llovera R, Ibendahl S, Castaño EM. The degradation of amyloid beta as a therapeutic strategy in Alzheimer's disease and cerebrovascular amyloidoses. Neurochem Res 2002; 27:1387-99. [PMID: 12512943 DOI: 10.1023/a:1021679817756] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The deposition of 4-kDa amyloid beta peptide in the brain is a prominent feature of several human diseases. Such process is heterogeneous in terms of causative factors, biochemical phenotype, localization and clinical manifestations. Amyloid beta accumulates in the neuropil or within the walls of cerebral vessels, and associates with dementia or stroke, both hereditary and sporadic. Amyloid beta is normally released by cells as soluble monomeric-dimeric species yet, under pathological conditions, it self-aggregates as soluble oligomers or insoluble fibrils that may be toxic to neurons and vascular cells. Lowering amyloid beta levels may be achieved by inhibiting its generation from the amyloid beta-precursor protein or by promoting its clearance by transport or degradation. We will summarize recent findings on brain proteases capable of degrading amyloid beta with a special focus on those enzymes for which there is genetic, transgenic or biochemical evidence suggesting that they may participate in the proteolysis of amyloid beta in vivo. We will also put in perspective their possible utilization as therapeutic agents in amyloid beta diseases.
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Affiliation(s)
- Laura Morelli
- Instituto de Química y Fisicoquímica Biológicas (IQUIFIB), CONICET, Cátedra de Química Biológica Patológica, Departamento de Química Biológica, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
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23
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Robinson SR, Bishop GM. Abeta as a bioflocculant: implications for the amyloid hypothesis of Alzheimer's disease. Neurobiol Aging 2002; 23:1051-72. [PMID: 12470802 DOI: 10.1016/s0197-4580(01)00342-6] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Research into Alzheimer's disease (AD) has been guided by the view that deposits of fibrillar amyloid-beta peptide (Abeta) are neurotoxic and are largely responsible for the neurodegeneration that accompanies the disease. This 'amyloid hypothesis' has claimed support from a wide range of molecular, genetic and animal studies. We critically review these observations and highlight inconsistencies between the predictions of the amyloid hypothesis and the published data. We show that the data provide equal support for a 'bioflocculant hypothesis', which posits that Abeta is normally produced to bind neurotoxic solutes (such as metal ions), while the precipitation of Abeta into plaques may be an efficient means of presenting these toxins to phagocytes. We conclude that if the deposition of Abeta represents a physiological response to injury then therapeutic treatments aimed at reducing the availability of Abeta may hasten the disease process and associated cognitive decline in AD.
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Affiliation(s)
- Stephen R Robinson
- Department of Psychology, Monash University, Clayton, Vic. 3800, Australia.
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24
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Abstract
Familial conformational diseases occur when a mutation alters the conformation of a protein resulting in abnormal intermolecular interactions, protein aggregation, and consequent tissue damage. The molecular mechanisms of conformational disease are best understood for the serine protease inhibitor (serpin) superfamily of proteins. The serpinopathies include alpha(1)-antitrypsin (SERPINA1) deficiency and the newly characterized familial encephalopathy with neuroserpin inclusion bodies (FENIB) resulting from mutations in the neuroserpin (SERPINI1) gene. This review discusses how insights gained from the study of the serpins may be used to guide our research into other common diseases such as Alzheimer disease, Huntington disease, and Parkinson disease.
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Affiliation(s)
- Damian C Crowther
- University of Cambridge Neurology Unit, Cambridge Institute for Medical Research, Cambridge, UK
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25
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Lichtenthaler SF, Beher D, Grimm HS, Wang R, Shearman MS, Masters CL, Beyreuther K. The intramembrane cleavage site of the amyloid precursor protein depends on the length of its transmembrane domain. Proc Natl Acad Sci U S A 2002; 99:1365-70. [PMID: 11805291 PMCID: PMC122196 DOI: 10.1073/pnas.032395699] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Proteolytic processing of the amyloid precursor protein by beta-secretase generates C99, which subsequently is cleaved by gamma-secretase, yielding the amyloid beta peptide (A beta). This gamma-cleavage occurs within the transmembrane domain (TMD) of C99 and is similar to the intramembrane cleavage of Notch. However, Notch and C99 differ in their site of intramembrane cleavage. The main gamma-cleavage of C99 occurs in the middle of the TMD, whereas the cleavage of Notch occurs close to the C-terminal end of the TMD, making it unclear whether both are cleaved by the same protease. To investigate whether gamma-cleavage always occurs in the middle of the TMD of C99 or may also occur at the end of the TMD, we generated C99-mutants with an altered length of the TMD and analyzed their gamma-cleavage in COS7 cells. The C terminus of A beta and thus the site of gamma-cleavage were determined by using monoclonal antibodies and mass spectrometry. Compared with C99-wild type (wt), most mutants with an altered length of the TMD changed the cleavage site of gamma-secretase, whereas control mutants with mutations outside the TMD did not. Thus, the length of the whole TMD is a major determinant for the cleavage site of gamma-secretase. Moreover, the C99-mutants were not only cleaved at one site but at two sites within their TMD. One cleavage site was located around the middle of the TMD, regardless of its actual length. An additional cleavage occurred within the N-terminal half of their TMD and thus at the opposite side of the Notch cleavage site.
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Affiliation(s)
- Stefan F Lichtenthaler
- Massachusetts General Hospital/Harvard Medical School, Wellman Building, 50 Blossom Street, Boston, MA 02114, USA.
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26
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Abstract
The amyloid beta-peptide (Abeta) is a principal component of the cerebral plaques found in the brains of patients with Alzeheimer's disease (AD). This insoluble 40- to 42-amino acid peptide is formed by the cleavage of the Abeta precursor protein (APP). The three proteases that cleave APP, alpha-, beta-, and gamma-secretases, have been implicated in the etiology of AD. beta-Secretase is a membrane-anchored protein with clear homology to soluble aspartyl proteases, and alpha-secretase displays characteristics of certain membrane-tethered metalloproteases. gamma-Secretase is apparently an oligomeric complex that includes the presenilins, which may be the catalytic component of this protease. Identification of the alpha-, beta-, and gamma-secretases provides potential targets for designing new drugs to treat AD.
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Affiliation(s)
- W P Esler
- Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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27
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Wolfe MS. Secretase targets for Alzheimer's disease: identification and therapeutic potential. J Med Chem 2001; 44:2039-60. [PMID: 11405641 DOI: 10.1021/jm0004897] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M S Wolfe
- Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
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28
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Iwata H, Tomita T, Maruyama K, Iwatsubo T. Subcellular compartment and molecular subdomain of beta-amyloid precursor protein relevant to the Abeta 42-promoting effects of Alzheimer mutant presenilin 2. J Biol Chem 2001; 276:21678-85. [PMID: 11283011 DOI: 10.1074/jbc.m007989200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Increased production of amyloid beta peptides ending at position 42 (Abeta42) is one of the pathogenic phenotypes caused by mutant forms of presenilins (PS) linked to familial Alzheimer's disease. To identify the subcellular compartment(s) in which familial Alzheimer's disease mutant PS2 (mt PS2) affects the gamma-cleavage of betaAPP to increase Abeta42, we co-expressed the C-terminal 99-amino acid fragment of betaAPP (C100) tagged with sorting signals to the endoplasmic reticulum (C100/ER) or to the trans-Golgi network (C100/TGN) together with mt PS2 in N2a cells. C100/TGN co-transfected with mt PS2 increased levels or ratios of intracellular as well as secreted Abeta42 at similar levels to those with C100 without signals (C100/WT), whereas C100/ER yielded a negligible level of Abeta, which was not affected by co-transfection of mt PS2. To identify the molecular subdomain of betaAPP required for the effects of mt PS2, we next co-expressed C100 variously truncated at the C-terminal cytoplasmic domain together with mt PS2. All types of C-terminally truncated C100 variants including that lacking the entire cytoplasmic domain yielded the secreted form of Abeta at levels comparable with those from C100/WT, and co-transfection of mt PS2 increased the secretion of Abeta42. These results suggest that (i) late intracellular compartments including TGN are the major sites in which Abeta42 is produced and up-regulated by mt PS2 and that (ii) the anterior half of C100 lacking the entire cytoplasmic domain is sufficient for the overproduction of Abeta42 caused by mt PS2.
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Affiliation(s)
- H Iwata
- Department of Neuropathology, Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1 Hongo Bunkyoku, Tokyo 113-0033, Japan
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29
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Abstract
The extracellular deposition of short amyloid peptides in the brain of patients is thought to be a central event in the pathogenesis of Alzheimer's Disease. The generation of the amyloid peptide occurs via a regulated cascade of cleavage events in its precursor protein, A beta PP. At least three enzymes are responsible for A beta PP proteolysis and have been tentatively named alpha-, beta- and gamma-secretases. The recent identification of several of these secretases is a major leap in the understanding how these secretases regulate amyloid peptide formation. Members of the ADAM family of metalloproteases are involved in the non-amyloidogenic alpha-secretase pathway. The amyloidogenic counterpart pathway is initiated by the recently cloned novel aspartate protease named BACE. The available data are conclusive and crown BACE as the long-sought beta-secretase. This enzyme is a prime candidate drug target for the development of therapy aiming to lower the amyloid burden in the disease. Finally, the gamma-secretases are intimately linked to the function of the presenilins. These multi-transmembrane domain proteins remain intriguing study objects. The hypothesis that the presenilins constitute a complete novel type of protease family, and are cleaving A beta PP within the transmembrane region, remains an issue of debate. Several questions remain unanswered and direct proof that they exert catalytic activity is still lacking. The subcellular localization of presenilins in neurons, their integration in functional multiprotein complexes and the recent identification of additional modulators of gamma-secretase, like nicastrin, indicate already that several players are involved. Nevertheless, the rapidly increasing knowledge in this area is already paving the road towards selective inhibitors of this secretase as well. It is hoped that such drugs, possibly in concert with the experimental vaccination therapies that are currently tested, will lead to a cure of this inexorable disease.
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Affiliation(s)
- D I Dominguez
- Flanders Interuniversitary Institute for Biotechnology and K.U. Leuven, Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Gasthuisberg, B-3000 Leuven, Belgium
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30
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Moore CL, Diehl TS, Selkoe DJ, Wolfe MS. Toward the characterization and identification of gamma-secretases using transition-state analogue inhibitors. Ann N Y Acad Sci 2001; 920:197-205. [PMID: 11193150 DOI: 10.1111/j.1749-6632.2000.tb06922.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The amyloid-beta protein (A beta), strongly implicated in the etiology of Alzheimer's disease (AD), is formed from the amyloid-beta precursor protein (APP) through sequential proteolysis by beta- and gamma-secretases. Cleavage by gamma-secretase takes place within the middle of the single transmembrane region of APP and results primarily in 40- and 42-amino acid A beta C-terminal variants, A beta 40 and A beta 42. The latter form of A beta is highly fibrillogenic, is invariably elevated in autosomal-dominant forms of AD, and is the major A beta component found presymptomatically in cerebral deposits. Thus, blocking production of A beta in general and A beta 42 in particular is considered an important therapeutic goal. We have developed transition-state analogue inhibitors of gamma-secretase as molecular probes for characterizing the active site of this enzyme, as pharmacological tools for understanding its role in biology, and as affinity labels toward its definitive identification. Specifically, we found that: (1) difluoro ketone and difluoro alcohol peptidomimetics are effective inhibitors of gamma-secretase activity in APP-transfected cells, strongly suggesting an aspartyl protease mechanism; (2) gamma-secretases that form A beta 40 and A beta 42 are pharmacologically distinct but are nevertheless closely similar; (3) large hydrophobic P1 substituents increase the inhibitory potency of these peptidomimetics, suggesting a large complementary S1 pocket for gamma-secretases; (4) A beta 42 production is increased several fold over control by these gamma-secretase inhibitors after replacement with inhibitor-free media; (5) a bromoacetamide derivative of one of these analogues continues to inhibit total A beta and A beta 42 production hours after replacement with compound-free media and should help identify the target(s) of these protease transition-state mimics.
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Affiliation(s)
- C L Moore
- Department of Pharmaceutical Sciences, University of Tennessee, Memphis, Tennessee 38163, USA
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31
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Abstract
Several processes are implicated in the neuropathology of Alzheimer's disease (AD), such as the deposition of amyloid, the formation of paired helical filaments and the proinflammatory activation of microglial and astroglial cells. Proinflammatory activation of glial cells has been a focus of research for a mere ten years now. However, the availability of and broad experience with anti-inflammatory drugs has led to several ongoing clinical trials to verify the capacity of anti-inflammatory drugs to ameliorate the deterioration in AD. The enzymatic cleavage of the amyloid-precursor-protein or the hyperphosphorylation of tau as well as the subsequent aggregation of the resulting products are further targets for drugs intended to delay the neuropathological destruction observed in AD.
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Affiliation(s)
- M H Hüll
- Dept. of Psychiatry, University of Freiburg, Germany
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32
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Affiliation(s)
- M S Wolfe
- Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
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33
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Moore CL, Leatherwood DD, Diehl TS, Selkoe DJ, Wolfe MS. Difluoro ketone peptidomimetics suggest a large S1 pocket for Alzheimer's gamma-secretase: implications for inhibitor design. J Med Chem 2000; 43:3434-42. [PMID: 10978191 DOI: 10.1021/jm000100f] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The final step in the generation of the amyloid-beta protein (Abeta), implicated in the etiology of Alzheimer's disease, is proteolysis within the transmembrane region of the amyloid precursor protein (APP) by gamma-secretase. Although considered an important target for therapeutic design, gamma-secretase has been neither well-characterized nor definitively identified. Previous studies in our laboratory using substrate-based difluoro ketone and difluoro alcohol transition-state analogue inhibitors suggest that gamma-secretase is an aspartyl protease with loose sequence specificity. To further characterize the active site of gamma-secretase, we prepared a series of difluoro ketone peptide analogues with varying steric bulkiness in the P1 position and tested the ability of these compounds to inhibit Abeta production in APP-transfected cells. Incorporation of bulky, aliphatic P1 side chains, such as sec-butyl or cyclohexylmethyl, led to increased gamma-secretase inhibitory potency, suggesting a large S1 pocket to accommodate these substituents and providing further evidence for loose sequence specificity. The cyclohexylmethyl P1 substituent allowed N-terminal truncation to a low-molecular-weight compound (<600 Da) that effectively blocked Abeta production (IC(50) approximately 5 microM). This finding suggests that optimal S1 binding may allow the development of potent inhibitors with ideal pharmaceutical properties. Moreover, a difluoro alcohol analogue with a cyclohexylmethyl P1 substituent was equipotent with its difluoro ketone counterpart, providing strong evidence that gamma-secretase is an aspartyl protease. All new analogues inhibited total Abeta and Abeta(42) production with the same rank order of potency and increased Abeta(42) production at low concentrations, providing further evidence for distinct gamma-secretases that are nevertheless closely similar with respect to active site topology and mechanism.
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Affiliation(s)
- C L Moore
- Department of Pharmaceutical Sciences, University of Tennessee, Memphis, Tennessee 38163, USA
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34
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Janus C, Chishti MA, Westaway D. Transgenic mouse models of Alzheimer's disease. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1502:63-75. [PMID: 10899432 DOI: 10.1016/s0925-4439(00)00033-8] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- C Janus
- Centre for Research in Neurodegenerative Diseases, University of Toronto, Ont., Canada
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35
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Abstract
Normal ageing and Alzheimer's disease (AD) have many features in common and, in many respects, both conditions only differ by quantitative criteria. A variety of genetic, medical and environmental factors modulate the ageing-related processes leading the brain into the devastation of AD. In accordance with the concept that AD is a metabolic disease, these risk factors deteriorate the homeostasis of the Ca(2+)-energy-redox triangle and disrupt the cerebral reserve capacity under metabolic stress. The major genetic risk factors (APP and presenilin mutations, Down's syndrome, apolipoprotein E4) are associated with a compromise of the homeostatic triangle. The pathophysiological processes leading to this vulnerability remain elusive at present, while mitochondrial mutations can be plausibly integrated into the metabolic scenario. The metabolic leitmotif is particularly evident with medical risk factors which are associated with an impaired cerebral perfusion, such as cerebrovascular diseases including stroke, cardiovascular diseases, hypo- and hypertension. Traumatic brain injury represents another example due to the persistent metabolic stress following the acute event. Thyroid diseases have detrimental sequela for cerebral metabolism as well. Furthermore, major depression and presumably chronic stress endanger susceptible brain areas mediated by a host of hormonal imbalances, particularly the HPA-axis dysregulation. Sociocultural and lifestyle factors like education, physical activity, diet and smoking may also modulate the individual risk affecting both reserve capacity and vulnerability. The pathophysiological relevance of trace metals, including aluminum and iron, is highly controversial; at any rate, they may adversely affect cellular defences, antioxidant competence in particular. The relative contribution of these factors, however, is as individual as the pattern of the factors. In familial AD, the genetic factors clearly drive the sequence of events. A strong interaction of fat metabolism and apoE polymorphism is suggested by intercultural epidemiological findings. In cultures, less plagued by the 'blessings' of the 'cafeteria diet-sedentary' Western lifestyle, apoE4 appears to be not a risk factor for AD. This intriguing evidence suggests that, analogous to cardiovascular diseases, apoE4 requires a hyperlipidaemic lifestyle to manifest as AD risk factor. Overall, the etiology of AD is a key paradigm for a gene-environment interaction. Copyright 2000 John Wiley & Sons, Ltd.
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Affiliation(s)
- Kurt Heininger
- Department of Neurology, Heinrich Heine University, Düsseldorf, Germany
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36
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Ancolio K, Dumanchin C, Barelli H, Warter JM, Brice A, Campion D, Frébourg T, Checler F. Unusual phenotypic alteration of beta amyloid precursor protein (betaAPP) maturation by a new Val-715 --> Met betaAPP-770 mutation responsible for probable early-onset Alzheimer's disease. Proc Natl Acad Sci U S A 1999; 96:4119-24. [PMID: 10097173 PMCID: PMC22430 DOI: 10.1073/pnas.96.7.4119] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have identified a novel beta amyloid precursor protein (betaAPP) mutation (V715M-betaAPP770) that cosegregates with early-onset Alzheimer's disease (AD) in a pedigree. Unlike other familial AD-linked betaAPP mutations reported to date, overexpression of V715M-betaAPP in human HEK293 cells and murine neurons reduces total Abeta production and increases the recovery of the physiologically secreted product, APPalpha. V715M-betaAPP significantly reduces Abeta40 secretion without affecting Abeta42 production in HEK293 cells. However, a marked increase in N-terminally truncated Abeta ending at position 42 (x-42Abeta) is observed, whereas its counterpart x-40Abeta is not affected. These results suggest that, in some cases, familial AD may be associated with a reduction in the overall production of Abeta but may be caused by increased production of truncated forms of Abeta ending at the 42 position.
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Affiliation(s)
- K Ancolio
- Institut de Pharmacologie Moléculaire et Cellulaire du Centre National de la Recherche Scientifique, UPR 411, 660 Route des Lucioles, Sophia Antipolis, 06560 Valbonne, France
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37
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Affiliation(s)
- K S Kosik
- Department of Neurology, Harvard Medical School and Brigham and Women's Hospital, 77 Avenue Louis Pasteur, Boston MA 02115, USA.
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38
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Lichtenthaler SF, Wang R, Grimm H, Uljon SN, Masters CL, Beyreuther K. Mechanism of the cleavage specificity of Alzheimer's disease gamma-secretase identified by phenylalanine-scanning mutagenesis of the transmembrane domain of the amyloid precursor protein. Proc Natl Acad Sci U S A 1999; 96:3053-8. [PMID: 10077635 PMCID: PMC15893 DOI: 10.1073/pnas.96.6.3053] [Citation(s) in RCA: 177] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Proteolytic processing of the amyloid precursor protein by beta-secretase yields A4CT (C99), which is cleaved further by the as yet unknown gamma-secretase, yielding the beta-amyloid (Abeta) peptide with 40 (Abeta40) or 42 residues (Abeta42). Because the position of gamma-secretase cleavage is crucial for the pathogenesis of Alzheimer's disease, we individually replaced all membrane-domain residues of A4CT outside the Abeta domain with phenylalanine, stably transfected the constructs in COS7 cells, and determined the effect of these mutations on the cleavage specificity of gamma-secretase (Abeta42/Abeta40 ratio). Compared with wild-type A4CT, mutations at Val-44, Ile-47, and Val-50 led to decreased Abeta42/Abeta40 ratios, whereas mutations at Thr-43, Ile-45, Val-46, Leu-49, and Met-51 led to increased Abeta42/Abeta40 ratios. A massive effect was observed for I45F (34-fold increase) making this construct important for the generation of animal models for Alzheimer's disease. Unlike the other mutations, A4CT-V44F was processed mainly to Abeta38, as determined by mass spectrometry. Our data provide a detailed model for the active site of gamma-secretase: gamma-secretase interacts with A4CT by binding to one side of the alpha-helical transmembrane domain of A4CT. Mutations in the transmembrane domain of A4CT interfere with the interaction between gamma-secretase and A4CT and, thus, alter the cleavage specificity of gamma-secretase.
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Affiliation(s)
- S F Lichtenthaler
- Center for Molecular Biology, University of Heidelberg, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
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39
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Luo JJ, Wallace W, Riccioni T, Ingram DK, Roth GS, Kusiak JW. Death of PC12 cells and hippocampal neurons induced by adenoviral-mediated FAD human amyloid precursor protein gene expression. J Neurosci Res 1999; 55:629-42. [PMID: 10082085 DOI: 10.1002/(sici)1097-4547(19990301)55:5<629::aid-jnr10>3.0.co;2-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We used adenoviral-mediated gene transfer of human amyloid precursor proteins (h-APPs) to evaluate the role of various h-APPs in causing neuronal cell death. We were able to infect PC12 cells with very high efficiency because approximately 90% of the cells were cytochemically positive for beta-galactosidase activity when an adenoviral vector containing LacZ cDNA was used to infect cells. Cells infected with adenovirus containing h-APP cDNA showed high-level transcription and expression of h-APP as measured by reverse transcriptase-polymerase chain reaction and Western immunoblot analyses, respectively. Intracellular and extracellular levels of h-APP were elevated approximately 17-and 24-fold in cultures infected with recombinant adenovirus containing wild-type mutant and 13- and 17-fold with V642F mutant. No elevation in h-APP was seen in cultures infected with antisense h-APP or null adenovirus. H-APP levels were maximal 3 days after infection. Overexpression of V642F mutant h-APP in PC12 cells and hippocampal neurons resulted in about a twofold increase in death compared with overexpression of wild-type h-APP. These results demonstrate the usefulness of recombinant adenoviral mediated gene transfer in cell culture studies and suggest that overexpression of a familial Alzheimer's disease mutant APP may be toxic to neuronal cells.
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Affiliation(s)
- J J Luo
- Molecular Neurobiology Unit, Laboratory of Biological Chemistry, National Institute on Aging, Baltimore, Maryland 21224, USA.
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40
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Kouchi Z, Sorimachi H, Suzuki K, Ishiura S. Proteasome inhibitors induce the association of Alzheimer's amyloid precursor protein with Hsc73. Biochem Biophys Res Commun 1999; 254:804-10. [PMID: 9920821 DOI: 10.1006/bbrc.1998.9977] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Amyloid precursor protein (APP) is a secretory membrane-bound protein that undergoes restrictive proteolysis and degradation with a short life span in the constitutive secretory pathway or in the endosomal/lysosomal compartment. The degradation machinery, including cellular trafficking and the restrictive cleavage of APP, is poorly understood. To gain further insight into the intracellular degradation mechanism of APP, we searched for effector proteins that interact with APP. We found that a cytosolic molecular chaperon, Hsc73, effectively interacts with the cytoplasmic domain of APP in the presence of proteasome inhibitors. Hsc73 binds to the cytoplasmic domain near the post-transmembrane region of APP and not to the KFERQ-related sequence, KFFEQ, at the C-terminal tail that is assumed to be the selective targeting signal for lysosomal proteolysis. The amounts of Hsc73 that bind to several APP species such as those found in pathological Familial Alzheimer's disease (FAD), Swedish, or Dutch type mutation, are almost identical, suggesting that an abnormal conformation around the secretory cleavage site or a pathological imbalance in APP processing are not irrelevant to the efficiency of Hsc73 binding.
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Affiliation(s)
- Z Kouchi
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
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41
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Abstract
The significance of amyloid beta protein, especially those ending at the 42nd residue (Abeta42), in the pathogenesis of familial Alzheimer's disease (FAD) linked to the mutations of presenilins, was examined by transfection studies using cultured cells and immunohistochemical analysis of autopsied brains. The levels of Abeta42 secreted from cells transfected with mutant presenilins linked to FAD, as well as the Abeta42 burden in the cortices of patients with presenilin mutation were elevated. Thus, mutations in presenilin genes may enhance the production and deposition of Abeta42 in the brains, thereby leading to Alzheimer's disease.
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Affiliation(s)
- T Iwatsubo
- Department of Neuropathology and Neuroscience, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
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