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Haut F, Argyrousi EK, Arancio O. Re-Arranging the Puzzle between the Amyloid-Beta and Tau Pathology: An APP-Centric Approach. Int J Mol Sci 2023; 25:259. [PMID: 38203429 PMCID: PMC10779219 DOI: 10.3390/ijms25010259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/04/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024] Open
Abstract
After several years of research in the field of Alzheimer's disease (AD), it is still unclear how amyloid-beta (Aβ) and Tau, two key hallmarks of the disease, mediate the neuropathogenic events that lead to AD. Current data challenge the "Amyloid Cascade Hypothesis" that has prevailed in the field of AD, stating that Aβ precedes and triggers Tau pathology that will eventually become the toxic entity in the progression of the disease. This perspective also led the field of therapeutic approaches towards the development of strategies that target Aβ or Tau. In the present review, we discuss recent literature regarding the neurotoxic role of both Aβ and Tau in AD, as well as their physiological function in the healthy brain. Consequently, we present studies suggesting that Aβ and Tau act independently of each other in mediating neurotoxicity in AD, thereafter, re-evaluating the "Amyloid Cascade Hypothesis" that places Tau pathology downstream of Aβ. More recent studies have confirmed that both Aβ and Tau could propagate the disease and induce synaptic and memory impairments via the amyloid precursor protein (APP). This finding is not only interesting from a mechanistic point of view since it provides better insights into the AD pathogenesis but also from a therapeutic point of view since it renders APP a common downstream effector for both Aβ and Tau. Subsequently, therapeutic strategies that act on APP might provide a more viable and physiologically relevant approach for targeting AD.
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Affiliation(s)
- Florence Haut
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, 630 West 168th Street, P&S, New York, NY 10032, USA; (F.H.); (E.K.A.)
| | - Elentina K. Argyrousi
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, 630 West 168th Street, P&S, New York, NY 10032, USA; (F.H.); (E.K.A.)
| | - Ottavio Arancio
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, 630 West 168th Street, P&S, New York, NY 10032, USA; (F.H.); (E.K.A.)
- Department of Medicine, Columbia University, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
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2
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Chen J, Fan A, Li S, Xiao Y, Fu Y, Chen JS, Zi D, Zeng LH, Tan J. APP mediates tau uptake and its overexpression leads to the exacerbated tau pathology. Cell Mol Life Sci 2023; 80:123. [PMID: 37071198 PMCID: PMC11071805 DOI: 10.1007/s00018-023-04774-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 03/11/2023] [Accepted: 03/16/2023] [Indexed: 04/19/2023]
Abstract
Alzheimer's disease (AD), as the most common type of dementia, has two pathological hallmarks, extracellular senile plaques composed of β-amyloid peptides and intracellular neurofibrillary tangles containing phosphorylated-tau protein. Amyloid precursor protein (APP) and tau each play central roles in AD, although how APP and tau interact and synergize in the disease process is largely unknown. Here, we showed that soluble tau interacts with the N-terminal of APP in vitro in cell-free and cell culture systems, which can be further confirmed in vivo in the brain of 3XTg-AD mouse. In addition, APP is involved in the cellular uptake of tau through endocytosis. APP knockdown or N-terminal APP-specific antagonist 6KApoEp can prevent tau uptake in vitro, resulting in an extracellular tau accumulation in cultured neuronal cells. Interestingly, in APP/PS1 transgenic mouse brain, the overexpression of APP exacerbated tau propagation. Moreover, in the human tau transgenic mouse brain, overexpression of APP promotes tau phosphorylation, which is significantly remediated by 6KapoEp. All these results demonstrate the important role of APP in the tauopathy of AD. Targeting the pathological interaction of N-terminal APP with tau may provide an important therapeutic strategy for AD.
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Affiliation(s)
- Jiang Chen
- Key Laboratory of Endemic and Ethnic Diseases, Laboratory of Molecular Biology, Ministry of Education, Guizhou Medical University, Guiyang, 550025, Guizhou, China
| | - Anran Fan
- Guizhou Provincial Key Laboratory for Regenerative Medicine, Stem Cell and Tissue Engineering Research Center, Ministry of Education, Guizhou Medical University, Guiyang, 550025, Guizhou, China
| | - Song Li
- First Affiliated Hospital of Dalian Medical University, Dalian, 116021, Liaoning, China
| | - Yan Xiao
- Key Laboratory of Endemic and Ethnic Diseases, Laboratory of Molecular Biology, Ministry of Education, Guizhou Medical University, Guiyang, 550025, Guizhou, China
| | - Yanlin Fu
- Key Laboratory of Endemic and Ethnic Diseases, Laboratory of Molecular Biology, Ministry of Education, Guizhou Medical University, Guiyang, 550025, Guizhou, China
| | - Jun-Sheng Chen
- Key Laboratory of Endemic and Ethnic Diseases, Laboratory of Molecular Biology, Ministry of Education, Guizhou Medical University, Guiyang, 550025, Guizhou, China
| | - Dan Zi
- Department of Gynecology, Guizhou Provincial People's Hospital, Guiyang, 550025, Guizhou, China
| | - Ling-Hui Zeng
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, 310015, Zhejiang, China
| | - Jun Tan
- Key Laboratory of Endemic and Ethnic Diseases, Laboratory of Molecular Biology, Ministry of Education, Guizhou Medical University, Guiyang, 550025, Guizhou, China.
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, 310015, Zhejiang, China.
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3
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Pal T, Paul R, Paul S. Phenylpropanoids on the Inhibition of β-Amyloid Aggregation and the Movement of These Molecules through the POPC Lipid Bilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:7775-7790. [PMID: 35687701 DOI: 10.1021/acs.langmuir.2c00827] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Alzheimer's disease (AD), caused by Aβ aggregation, is a major concern in medical research. It is a neurodegenerative disorder, leading to a loss of cognitive abilities, which is still claiming the lives of many people all over the world. This poses a challenge before the scientific community to discover effective drugs which can prevent such toxic aggregation. Recent experimental findings suggest the potency of two naturally-occurring phenylpropanoids, Schizotenuin A (SCH) and Lycopic Acid B (LAB) which can effectively combat the deleterious effects of Aβ aggregation, although nothing is known about their mechanism of inhibition. In this work, we deal with an extensive computational study on the inhibitory effects of these inhibitors by using an all-atom molecular dynamics simulation to interpret the underlying mechanism of their inhibitory processes. A series of investigations is carried out while studying the various structural and conformational changes of the peptide chains in the absence and presence of inhibitors. To investigate the details of the interactions between the peptide residues and inhibitors, nonbonding energy calculations, the radial distribution function, the coordination number of water and inhibitor molecules around the peptide residues, and hydrogen-bonding interactions are calculated. The potential of mean force (PMF) is calculated to estimate aggregate formation from their free-energy profiles. It is seen that the hydrophobic core of the KLVFFAE undergoes aggregation and that these inhibitors show great promise in preventing the onset of AD in the future by preventing Aβ aggregation. Also, the translocation studies on these inhibitors through a model POPC lipid bilayer shed light on their permeation properties and biocompatibility.
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Affiliation(s)
- Triasha Pal
- Department of Chemistry, Indian Institute of Technology, Guwahati, Assam, India 781039
| | - Rabindranath Paul
- Department of Chemistry, Indian Institute of Technology, Guwahati, Assam, India 781039
| | - Sandip Paul
- Department of Chemistry, Indian Institute of Technology, Guwahati, Assam, India 781039
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4
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Berrocal M, Mata AM. The Plasma Membrane Ca 2+-ATPase, a Molecular Target for Tau-induced Cytosolic Calcium Dysregulation. Neuroscience 2022; 518:112-118. [PMID: 35469971 DOI: 10.1016/j.neuroscience.2022.04.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/04/2022] [Accepted: 04/18/2022] [Indexed: 11/28/2022]
Abstract
Disruption of calcium (Ca2+) homeostasis is emerging as a prevalent feature of aging and aging-associated neurodegenerative diseases, including Alzheimer's disease (AD), the most common type of tauopathy. This disease is characterized by the combined presence of extracellular neuritic plaques composed by amyloid β-peptides (Aβ) and neurofibrillary tangles of tau. The association of calcium dyshomeostasis with Aβ has been extensively studied, however its link with tau has been less investigated. Thus, this review will concentrate on the functional link between tau and the plasma membrane Ca2+ pump (PMCA) and other membrane proteins involved in the regulation of intracellular calcium and/or its association with neurodegeneration.
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Affiliation(s)
- María Berrocal
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, 06006 Badajoz, Spain; Instituto de Biomarcadores de Patologías Moleculares, Universidad de Extremadura, 06006 Badajoz, Spain
| | - Ana M Mata
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, 06006 Badajoz, Spain; Instituto de Biomarcadores de Patologías Moleculares, Universidad de Extremadura, 06006 Badajoz, Spain.
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5
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Britton RJ, Hutchison JM, Sanders CR. The transmembrane amyloid precursor C99 protein exhibits non-specific interaction with tau. Biochem Biophys Res Commun 2021; 576:48-52. [PMID: 34481234 DOI: 10.1016/j.bbrc.2021.08.075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 08/25/2021] [Indexed: 11/17/2022]
Abstract
Historically, the two most prominent proteins in Alzheimer's disease (AD) research have been the amyloid precursor protein (APP) and the microtubule assembly protein tau. In the classical model for the etiology of AD, amyloid-β (Aβ)-an APP derivative and hyperphosphorylated tau form aggregates in the brain that underlie the pathogenesis of the disease. However, the connection between Aβ and tau pathologies remains unclear. Several studies have provided evidence that the presence of Aβ can induce or enhance neurofibrillary tangle formation by tau. Others have reported a direct interaction between tau and short fragments of the APP transmembrane domain, C99. Structural studies of C99 show that these in vitro tau-binding fragments of C99 are buried in the lipid bilayer and are likely unavailable to bind tau in vivo. Given the importance of APP and tau in AD, we sought to characterize the potential interaction of the Aβ precursor, full length C99, and tau in vitro using NMR spectroscopy. We found that C99 and soluble tau interact only weakly and, most likely, non-specifically.
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Affiliation(s)
- Rhett J Britton
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37240, USA
| | - James M Hutchison
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37240, USA; Chemical and Physical Biology Graduate Program, Vanderbilt University, Nashville, TN, 37240, USA
| | - Charles R Sanders
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37240, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN, 37240, USA; Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
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6
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Bok E, Leem E, Lee BR, Lee JM, Yoo CJ, Lee EM, Kim J. Role of the Lipid Membrane and Membrane Proteins in Tau Pathology. Front Cell Dev Biol 2021; 9:653815. [PMID: 33996814 PMCID: PMC8119898 DOI: 10.3389/fcell.2021.653815] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 04/09/2021] [Indexed: 12/12/2022] Open
Abstract
Abnormal accumulation of misfolded tau aggregates is a pathological hallmark of various tauopathies including Alzheimer’s disease (AD). Although tau is a cytosolic microtubule-associated protein enriched in neurons, it is also found in extracellular milieu, such as interstitial fluid, cerebrospinal fluid, and blood. Accumulating evidence showed that pathological tau spreads along anatomically connected areas in the brain through intercellular transmission and templated misfolding, thereby inducing neurodegeneration and cognitive dysfunction. In line with this, the spatiotemporal spreading of tau pathology is closely correlated with cognitive decline in AD patients. Although the secretion and uptake of tau involve multiple different pathways depending on tau species and cell types, a growing body of evidence suggested that tau is largely secreted in a vesicle-free forms. In this regard, the interaction of vesicle-free tau with membrane is gaining growing attention due to its importance for both of tau secretion and uptake as well as aggregation. Here, we review the recent literature on the mechanisms of the tau-membrane interaction and highlights the roles of lipids and proteins at the membrane in the tau-membrane interaction as well as tau aggregation.
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Affiliation(s)
- Eugene Bok
- Dementia Research Group, Korea Brain Research Institute, Daegu, South Korea
| | - Eunju Leem
- Dementia Research Group, Korea Brain Research Institute, Daegu, South Korea
| | - Bo-Ram Lee
- Dementia Research Group, Korea Brain Research Institute, Daegu, South Korea
| | - Ji Min Lee
- Dementia Research Group, Korea Brain Research Institute, Daegu, South Korea.,School of Life Sciences, Kyungpook National University, Daegu, South Korea
| | - Chang Jae Yoo
- Dementia Research Group, Korea Brain Research Institute, Daegu, South Korea.,Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Eun Mi Lee
- Dementia Research Group, Korea Brain Research Institute, Daegu, South Korea.,Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Jaekwang Kim
- Dementia Research Group, Korea Brain Research Institute, Daegu, South Korea
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7
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Maron R, Armony G, Tsoory M, Wilchek M, Frenkel D, Arnon R. Peptide Interference with APP and Tau Association: Relevance to Alzheimer's Disease Amelioration. Int J Mol Sci 2020; 21:E3270. [PMID: 32380752 PMCID: PMC7246762 DOI: 10.3390/ijms21093270] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 01/02/2023] Open
Abstract
The two major proteins involved in Alzheimer's disease (AD) are the amyloid precursor protein (APP) and Tau. Here, we demonstrate that these two proteins can bind to each other. Four possible peptides APP1 (390-412), APP2 (713-730), Tau1 (19-34) and Tau2 (331-348), were predicted to be involved in this interaction, with actual binding confirmed for APP1 and Tau1. In vivo studies were performed in an Alzheimer Disease animal model-APP double transgenic (Tg) 5xFAD-as well as in 5xFAD crossed with Tau transgenic 5xFADXTau (FT), which exhibit declined cognitive reduction at four months of age. Nasal administration of APP1 and Tau1 mixture, three times a week for four or five months, reduced amyloid plaque burden as well as the level of soluble Aβ 1-42 in the brain. The treatment prevented the deterioration of cognitive functions when initiated at the age of three months, before cognitive deficiency was evident, and also at the age of six months, when such deficiencies are already observed, leading to a full regain of cognitive function.
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Affiliation(s)
- Ruth Maron
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Gad Armony
- Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Michael Tsoory
- Department of Veterinary Resources, Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Meir Wilchek
- Department of Biomolecular Science, Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Dan Frenkel
- Department of Neurobiology, School of Neurobiology, Biochemistry and Biophysics, The George S. Wise Faculty of Life Sciences, Sagol School of Neuroscience Tel Aviv University, Tel Aviv 6997801, Israel;
| | - Ruth Arnon
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel;
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8
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Bee venom phospholipase A2 ameliorates Alzheimer's disease pathology in Aβ vaccination treatment without inducing neuro-inflammation in a 3xTg-AD mouse model. Sci Rep 2018; 8:17369. [PMID: 30478329 PMCID: PMC6255868 DOI: 10.1038/s41598-018-35030-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 10/29/2018] [Indexed: 01/08/2023] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia and is characterized by an imbalance between the production and clearance of amyloid-beta (Aβ) and tau proteins. Although vaccination against Aβ peptide results in a dramatic reduction in Aβ pathology in experimental mouse models, the initial clinical trial for an active Aβ vaccine was halted early due to the development of acute meningoencephalitis in 6% of the immunized patients, which likely involved a T-cell mediated pro-inflammatory response. In this study, we aimed to determine whether bee venom phospholipase A2 (bvPLA2) treatment would induce Tregs and ameliorate AD pathology without unwanted T cell-mediated inflammation. First, we investigated the effects of bvPLA2 on the inflammatory infiltration caused by Aβ vaccination. Inflammatory aggregates of CD3+ T lymphocytes and macrophages were found in the brains and spinal cords of mice treated with Aβ. However, administration of bvPLA2 dramatically eliminated central nervous system inflammation following Aβ immunization. In AD model mice (3xTg-AD mice), bvPLA2 administration significantly ameliorated cognitive deficits and reduced Aβ burdens in the brains of Aβ-vaccinated 3xTg-AD mice. Additionally, we examined brain glucose metabolism using positron emission tomography with 18F-2 fluoro-2-deoxy-d-glucose. Cerebral glucose uptake was considerably higher in the brains of Aβ-vaccinated 3xTg-AD mice that received bvPLA2 than those that did not. The present study suggests that the modulation of Treg populations via bvPLA2 treatment may be a new therapeutic approach to attenuate the progression of AD in conjunction with Aβ vaccination therapy without an adverse inflammatory response.
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9
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Gulisano W, Maugeri D, Baltrons MA, Fà M, Amato A, Palmeri A, D’Adamio L, Grassi C, Devanand D, Honig LS, Puzzo D, Arancio O. Role of Amyloid-β and Tau Proteins in Alzheimer's Disease: Confuting the Amyloid Cascade. J Alzheimers Dis 2018; 64:S611-S631. [PMID: 29865055 PMCID: PMC8371153 DOI: 10.3233/jad-179935] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The "Amyloid Cascade Hypothesis" has dominated the Alzheimer's disease (AD) field in the last 25 years. It posits that the increase of amyloid-β (Aβ) is the key event in AD that triggers tau pathology followed by neuronal death and eventually, the disease. However, therapeutic approaches aimed at decreasing Aβ levels have so far failed, and tau-based clinical trials have not yet produced positive findings. This begs the question of whether the hypothesis is correct. Here we have examined literature on the role of Aβ and tau in synaptic dysfunction, memory loss, and seeding and spreading of AD, highlighting important parallelisms between the two proteins in all of these phenomena. We discuss novel findings showing binding of both Aβ and tau oligomers to amyloid-β protein precursor (AβPP), and the requirement for the presence of this protein for both Aβ and tau to enter neurons and induce abnormal synaptic function and memory. Most importantly, we propose a novel view of AD pathogenesis in which extracellular oligomers of Aβ and tau act in parallel and upstream of AβPP. Such a view will call for a reconsideration of therapeutic approaches directed against Aβ and tau, paving the way to an increased interest toward AβPP, both for understanding the pathogenesis of the disease and elaborating new therapeutic strategies.
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Affiliation(s)
- Walter Gulisano
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy
| | - Daniele Maugeri
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy
| | - Marian A. Baltrons
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, NY, USA
- Department of Biochemistry and Molecular Biology and Institute of Biotechnology and Biomedicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Mauro Fà
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Arianna Amato
- Department of Anaesthesiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Agostino Palmeri
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy
| | - Luciano D’Adamio
- Department of Pharmacology, Physiology and Neuroscience, Rutgers University, Newark, NJ, USA
| | - Claudio Grassi
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - D.P. Devanand
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, NY, USA
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Lawrence S. Honig
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, NY, USA
- Department of Neurology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Daniela Puzzo
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy
| | - Ottavio Arancio
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, NY, USA
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10
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Pentkowski NS, Berkowitz LE, Thompson SM, Drake EN, Olguin CR, Clark BJ. Anxiety-like behavior as an early endophenotype in the TgF344-AD rat model of Alzheimer's disease. Neurobiol Aging 2018; 61:169-176. [PMID: 29107184 PMCID: PMC7944488 DOI: 10.1016/j.neurobiolaging.2017.09.024] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 09/01/2017] [Accepted: 09/23/2017] [Indexed: 12/31/2022]
Abstract
Alzheimer's disease (AD) is characterized by progressive cognitive decline and the presence of aggregates of amyloid beta (plaques) and hyperphosphorylated tau (tangles). Early diagnosis through neuropsychological testing is difficult due to comorbidity of symptoms between AD and other types of dementia. As a result, there is a need to identify the range of behavioral phenotypes expressed in AD. In the present study, we utilized a transgenic rat (TgF344-AD) model that bears the mutated amyloid precursor protein as well as presenilin-1 genes, resulting in progressive plaque and tangle pathogenesis throughout the cortex. We tested young adult male and female TgF344-AD rats in a spatial memory task in the Morris water maze and for anxiety-like behavior in the elevated plus-maze. Results indicated that regardless of sex, TgF344-AD rats exhibited increased anxiety-like behavior in the elevated plus-maze, which occurred without significant deficits in the spatial memory. Together, these results indicate that enhanced anxiety-like behavior represents an early-stage behavioral marker in the TgF344-AD rat model.
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Affiliation(s)
| | - Laura E Berkowitz
- Department of Psychology, University of New Mexico, Albuquerque, NM, USA
| | - Shannon M Thompson
- Department of Psychology, University of New Mexico, Albuquerque, NM, USA
| | - Emma N Drake
- Department of Psychology, University of New Mexico, Albuquerque, NM, USA
| | - Carlos R Olguin
- Department of Psychology, University of New Mexico, Albuquerque, NM, USA
| | - Benjamin J Clark
- Department of Psychology, University of New Mexico, Albuquerque, NM, USA.
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11
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Puzzo D, Piacentini R, Fá M, Gulisano W, Li Puma DD, Staniszewski A, Zhang H, Tropea MR, Cocco S, Palmeri A, Fraser P, D'Adamio L, Grassi C, Arancio O. LTP and memory impairment caused by extracellular Aβ and Tau oligomers is APP-dependent. eLife 2017; 6. [PMID: 28696204 PMCID: PMC5529106 DOI: 10.7554/elife.26991] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/10/2017] [Indexed: 12/21/2022] Open
Abstract
The concurrent application of subtoxic doses of soluble oligomeric forms of human amyloid-beta (oAβ) and Tau (oTau) proteins impairs memory and its electrophysiological surrogate long-term potentiation (LTP), effects that may be mediated by intra-neuronal oligomers uptake. Intrigued by these findings, we investigated whether oAβ and oTau share a common mechanism when they impair memory and LTP in mice. We found that as already shown for oAβ, also oTau can bind to amyloid precursor protein (APP). Moreover, efficient intra-neuronal uptake of oAβ and oTau requires expression of APP. Finally, the toxic effect of both extracellular oAβ and oTau on memory and LTP is dependent upon APP since APP-KO mice were resistant to oAβ- and oTau-induced defects in spatial/associative memory and LTP. Thus, APP might serve as a common therapeutic target against Alzheimer's Disease (AD) and a host of other neurodegenerative diseases characterized by abnormal levels of Aβ and/or Tau. DOI:http://dx.doi.org/10.7554/eLife.26991.001
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Affiliation(s)
- Daniela Puzzo
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Roberto Piacentini
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Mauro Fá
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, United States
| | - Walter Gulisano
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Domenica D Li Puma
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Agnes Staniszewski
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, United States
| | - Hong Zhang
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, United States
| | - Maria Rosaria Tropea
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Sara Cocco
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Agostino Palmeri
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Paul Fraser
- Tanz Centre for Research in Neurodegenerative Diseases and Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - Luciano D'Adamio
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, United States
| | - Claudio Grassi
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Ottavio Arancio
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New york, United States
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12
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Li X, Lei P, Tuo Q, Ayton S, Li QX, Moon S, Volitakis I, Liu R, Masters CL, Finkelstein DI, Bush AI. Enduring Elevations of Hippocampal Amyloid Precursor Protein and Iron Are Features of β-Amyloid Toxicity and Are Mediated by Tau. Neurotherapeutics 2015; 12:862-73. [PMID: 26260389 PMCID: PMC4604188 DOI: 10.1007/s13311-015-0378-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The amyloid cascade hypothesis of Alzheimer's disease (AD) positions tau protein as a downstream mediator of β-amyloid (Aβ) toxicity This is largely based on genetic cross breeding, which showed that tau ablation in young (3-7-month-old) transgenic mice overexpressing mutant amyloid precursor protein (APP) abolished the phenotype of the APP AD model. This evidence is complicated by the uncertain impact of overexpressing mutant APP, rather than Aβ alone, and for potential interactions between tau and overexpressed APP. Cortical iron elevation is also implicated in AD, and tau promotes iron export by trafficking APP to the neuronal surface. Here, we utilized an alternative model of Aβ toxicity by directly injecting Aβ oligomers into the hippocampus of young and old wild-type and tau knockout mice. We found that ablation of tau protected against Aβ-induced cognitive impairment, hippocampal neuron loss, and iron accumulation. Despite injected human Aβ being eliminated after 5 weeks, enduring changes, including increased APP levels, tau reduction, tau phosphorylation, and iron accumulation, were observed. While the results from our study support the amyloid cascade hypothesis, they also suggest that downstream effectors of Aβ, which propagate toxicity after Aβ has been cleared, may be tractable therapeutic targets.
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Affiliation(s)
- Xuling Li
- Department of Neurology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, 150001, China
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Peng Lei
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052, Victoria, Australia.
| | - Qingzhang Tuo
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052, Victoria, Australia
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Scott Ayton
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Qiao-Xin Li
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Steve Moon
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Irene Volitakis
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Rong Liu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Colin L Masters
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052, Victoria, Australia
| | - David I Finkelstein
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052, Victoria, Australia
| | - Ashley I Bush
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052, Victoria, Australia.
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Tau proteins in the temporal and frontal cortices in patients with vascular dementia. J Neuropathol Exp Neurol 2015; 74:148-57. [PMID: 25575131 DOI: 10.1097/nen.0000000000000157] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
We previously reported that, in the brains of older patients with vascular dementia (VaD), there is a distinctive accumulation of detergent-extractable soluble amyloid-β, with a predominance of Aβ42 species. It is unclear, however, if tau proteins also accumulate in the brains of older VaD subjects. Using antibody-specific immunoassays, we assessed concentrations of total tau (t-tau) and phosphorylated tau protein, measured at 3 phosphorylated sites (i.e. Thr181, Ser202/Thr205, and Ser262), as well as synaptophysin in the temporal and frontal cortices of 18 VaD, 16 Alzheimer disease (AD), and 16 normal age-matched control subjects. There was selective loss of t-tau protein in VaD compared with controls and AD subjects (p < 0.021 and p < 0.001, respectively). In contrast, phosphorylated tau levels were similar to controls in VaD in both regions, but they were increased in the temporal lobes of patients with AD (p < 0.01 and p < 0.0001 for Ser202/Thr205 and Ser262 phosphorylated sites, respectively). The reduced t-tau in the VaD group was unrelated to any low-level neurofibrillary or amyloid pathology or age at death. These findings suggest that breaches of microvascular or microstructural tissue integrity subsequent to ischemic injury in older age may modify tau protein metabolism or phosphorylation and have effects on the burden of neurofibrillary pathology characteristic of AD.
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Abstract
PURPOSE OF REVIEW We reviewed clinical trials on active and passive anti-β-amyloid (Aβ) immunotherapy for the treatment of Alzheimer's disease with a particular focus on monoclonal antibodies against Aβ. RECENT FINDINGS Studies on anti-Alzheimer's disease immunotherapy published in the period from January 2012 to October 2013 were reviewed. SUMMARY Both active and passive anti-Aβ immunotherapies were shown to clear brain Aβ deposits. However, an active anti-Aβ vaccine (AN1792) has been discontinued because it caused meningoencephalitis in 6% of Alzheimer's disease patients treated. Among passive immunotherapeutics, two Phase III clinical trials in mild-to-moderate Alzheimer's disease patients with bapineuzumab, a humanized monoclonal antibody directed at the N-terminal sequence of Aβ, were disappointing. Another antibody, solanezumab, directed at the mid-region of Aβ, failed in two Phase III clinical trials in mild-to-moderate Alzheimer's disease patients. A third Phase III study with solanezumab is ongoing in mildly affected Alzheimer's disease patients based on encouraging results in this subgroup of patients. Second-generation active Aβ vaccines (ACC-001, CAD106, and Affitope AD02) and new passive anti-Aβ immunotherapies (gantenerumab and crenezumab) are being tested in prodromal Alzheimer's disease patients, in presymptomatic individuals with Alzheimer's disease-related mutations, or in asymptomatic individuals at risk of developing Alzheimer's disease to definitely test the Aβ cascade hypothesis of Alzheimer's disease.
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Panza F, Solfrizzi V, Imbimbo BP, Tortelli R, Santamato A, Logroscino G. Amyloid-based immunotherapy for Alzheimer's disease in the time of prevention trials: the way forward. Expert Rev Clin Immunol 2014; 10:405-19. [DOI: 10.1586/1744666x.2014.883921] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Manczak M, Reddy PH. Abnormal interaction of oligomeric amyloid-β with phosphorylated tau: implications to synaptic dysfunction and neuronal damage. J Alzheimers Dis 2014; 36:285-95. [PMID: 23594602 DOI: 10.3233/jad-130275] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative mental illness characterized by memory loss, multiple cognitive impairments, and changes in personality and behavior. The purpose of our study was to determine the interaction between monomeric and oligomeric amyloid-β (Aβ) and phosphorylated tau in AD neurons. Using postmortem brains from AD patients at different stages of disease progression and control subjects, and also from AβPP, AβPPxPS1, and 3xTg-AD mice, we studied the physical interaction between Aβ and phosphorylated tau. Using immunohistological and double-immunofluorescence analyses, we also studied the localization of monomeric and oligomeric Aβ with phosphorylated tau. We found monomeric and oligomeric Aβ interacted with phosphorylated tau in neurons affected by AD. Further, these interactions progressively increased with the disease process. These findings led us to conclude that Aβ interacts with phosphorylated tau and may damage neuronal structure and function, particularly synapses, leading to cognitive decline in AD patients. Our findings suggest that binding sites between Aβ and phosphorylated tau need to be identified and molecules developed to inhibit this interaction.
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Affiliation(s)
- Maria Manczak
- Neurogenetics Laboratory, Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006, USA
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Leroy K, Ando K, Laporte V, Dedecker R, Suain V, Authelet M, Héraud C, Pierrot N, Yilmaz Z, Octave JN, Brion JP. Lack of tau proteins rescues neuronal cell death and decreases amyloidogenic processing of APP in APP/PS1 mice. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:1928-40. [PMID: 23026200 DOI: 10.1016/j.ajpath.2012.08.012] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 07/04/2012] [Accepted: 08/09/2012] [Indexed: 12/12/2022]
Abstract
Lack of tau expression has been reported to protect against excitotoxicity and to prevent memory deficits in mice expressing mutant amyloid precursor protein (APP) identified in familial Alzheimer disease. In APP mice, mutant presenilin 1 (PS1) enhances generation of Aβ42 and inhibits cell survival pathways. It is unknown whether the deficient phenotype induced by concomitant expression of mutant PS1 is rescued by absence of tau. In this study, we have analyzed the effect of tau deletion in mice expressing mutant APP and PS1. Although APP/PS1/tau(+/+) mice had a reduced survival, developed spatial memory deficits at 6 months and motor impairments at 12 months, these deficits were rescued in APP/PS1/tau(-/-) mice. Neuronal loss and synaptic loss in APP/PS1/tau(+/+) mice were rescued in the APP/PS1/tau(-/-) mice. The amyloid plaque burden was decreased by roughly 50% in the cortex and the spinal cord of the APP/PS1/tau(-/-) mice. The levels of soluble and insoluble Aβ40 and Aβ42, and the Aβ42/Aβ40 ratio were reduced in APP/PS1/tau(-/-) mice. Levels of phosphorylated APP, of β-C-terminal fragments (CTFs), and of β-secretase 1 (BACE1) were also reduced, suggesting that β-secretase cleavage of APP was reduced in APP/PS1/tau(-/-) mice. Our results indicate that tau deletion had a protective effect against amyloid induced toxicity even in the presence of mutant PS1 and reduced the production of Aβ.
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Affiliation(s)
- Karelle Leroy
- Laboratory of Histology, Neuroanatomy, and Neuropathology, Université Libre de Bruxelles, 808 Route de Lennik, Brussels, Belgium
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18
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Panza F, Frisardi V, Solfrizzi V, Imbimbo BP, Logroscino G, Santamato A, Greco A, Seripa D, Pilotto A. Immunotherapy for Alzheimer's disease: from anti-β-amyloid to tau-based immunization strategies. Immunotherapy 2012; 4:213-38. [PMID: 22339463 DOI: 10.2217/imt.11.170] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The exact mechanisms leading to Alzheimer's disease (AD) are largely unknown, limiting the identification of effective disease-modifying therapies. The two principal neuropathological hallmarks of AD are extracellular β-amyloid (Aβ), peptide deposition (senile plaques) and intracellular neurofibrillary tangles containing hyperphosphorylated tau protein. During the last decade, most of the efforts of the pharmaceutical industry were directed against the production and accumulation of Aβ. The most innovative of the pharmacological approaches was the stimulation of Aβ clearance from the brain of AD patients via the administration of Aβ antigens (active vaccination) or anti-Aβ antibodies (passive vaccination). Several active and passive anti-Aβ vaccines are under clinical investigation. Unfortunately, the first active vaccine (AN1792, consisting of preaggregate Aβ and an immune adjuvant, QS-21) was abandoned because it caused meningoencephalitis in approximately 6% of treated patients. Anti-Aβ monoclonal antibodies (bapineuzumab and solanezumab) are now being developed. The clinical results of the initial studies with bapineuzumab were equivocal in terms of cognitive benefit. The occurrence of vasogenic edema after bapineuzumab, and more rarely brain microhemorrhages (especially in Apo E ε4 carriers), has raised concerns on the safety of these antibodies directed against the N-terminus of the Aβ peptide. Solanezumab, a humanized anti-Aβ monoclonal antibody directed against the midregion of the Aβ peptide, was shown to neutralize soluble Aβ species. Phase II studies showed a good safety profile of solanezumab, while studies on cerebrospinal and plasma biomarkers documented good signals of pharmacodynamic activity. Although some studies suggested that active immunization may be effective against tau in animal models of AD, very few studies regarding passive immunization against tau protein are currently available. The results of the large, ongoing Phase III trials with bapineuzumab and solanezumab will tell us if monoclonal anti-Aβ antibodies may slow down the rate of deterioration of AD. Based on the new diagnostic criteria of AD and on recent major failures of anti-Aβ drugs in mild-to-moderate AD patients, one could argue that clinical trials on potential disease-modifying drugs, including immunological approaches, should be performed in the early stages of AD.
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Affiliation(s)
- Francesco Panza
- Geriatric Unit & Gerontology-Geriatric Research Laboratory, IRCCS Casa Sollievo della Sofferenza, Foggia, Italy.
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19
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Tau deficiency induces parkinsonism with dementia by impairing APP-mediated iron export. Nat Med 2012; 18:291-5. [PMID: 22286308 DOI: 10.1038/nm.2613] [Citation(s) in RCA: 446] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 11/29/2011] [Indexed: 12/11/2022]
Abstract
The microtubule-associated protein tau has risk alleles for both Alzheimer's disease and Parkinson's disease and mutations that cause brain degenerative diseases termed tauopathies. Aggregated tau forms neurofibrillary tangles in these pathologies, but little is certain about the function of tau or its mode of involvement in pathogenesis. Neuronal iron accumulation has been observed pathologically in the cortex in Alzheimer's disease, the substantia nigra (SN) in Parkinson's disease and various brain regions in the tauopathies. Here we report that tau-knockout mice develop age-dependent brain atrophy, iron accumulation and SN neuronal loss, with concomitant cognitive deficits and parkinsonism. These changes are prevented by oral treatment with a moderate iron chelator, clioquinol. Amyloid precursor protein (APP) ferroxidase activity couples with surface ferroportin to export iron, but its activity is inhibited in Alzheimer's disease, thereby causing neuronal iron accumulation. In primary neuronal culture, we found loss of tau also causes iron retention, by decreasing surface trafficking of APP. Soluble tau levels fall in affected brain regions in Alzheimer's disease and tauopathies, and we found a similar decrease of soluble tau in the SN in both Parkinson's disease and the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model. These data suggest that the loss of soluble tau could contribute to toxic neuronal iron accumulation in Alzheimer's disease, Parkinson's disease and tauopathies, and that it can be rescued pharmacologically.
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Armstrong RA. The pathogenesis of Alzheimer's disease: a reevaluation of the "amyloid cascade hypothesis". Int J Alzheimers Dis 2011; 2011:630865. [PMID: 21331369 PMCID: PMC3038555 DOI: 10.4061/2011/630865] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 01/04/2011] [Indexed: 12/27/2022] Open
Abstract
The most influential theory to explain the pathogenesis of Alzheimer's disease (AD) has been the "Amyloid Cascade Hypothesis" (ACH) first formulated in 1992. The ACH proposes that the deposition of β-amyloid (Aβ) is the initial pathological event in AD leading to the formation of senile plaques (SPs) and then to neurofibrillary tangles (NFTs) death of neurons, and ultimately dementia. This paper examines two questions regarding the ACH: (1) is there a relationship between the pathogenesis of SPs and NFTs, and (2) what is the relationship of these lesions to disease pathogenesis? These questions are examined in relation to studies of the morphology and molecular determinants of SPs and NFTs, the effects of gene mutation, degeneration induced by head injury, the effects of experimentally induced brain lesions, transgenic studies, and the degeneration of anatomical pathways. It was concluded that SPs and NFTs develop independently and may be the products rather than the causes of neurodegeneration in AD. A modification to the ACH is proposed which may better explain the pathogenesis of AD, especially of late-onset cases of the disease.
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Medeiros R, Baglietto-Vargas D, LaFerla FM. The role of tau in Alzheimer's disease and related disorders. CNS Neurosci Ther 2010; 17:514-24. [PMID: 20553310 DOI: 10.1111/j.1755-5949.2010.00177.x] [Citation(s) in RCA: 177] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Tau, the microtubule-associated protein, forms insoluble filaments that accumulate as neurofibrillary tangles in Alzheimer's disease (AD) and related tauopathies. Under physiological conditions, tau regulates the assembly and maintenance of the structural stability of microtubules. In the diseased brain, however, tau becomes abnormally hyperphosphorylated, which ultimately causes the microtubules to disassemble, and the free tau molecules aggregate into paired helical filaments. A large body of evidence suggests that tau hyperphosphorylation results from perturbation of cellular signaling, mainly through imbalance in the activities of different protein kinases and phosphatases. In AD, it appears that ß-amyloid peptide (Aß) plays a pivotal role in triggering this imbalance. In this review, we summarize our current understanding of the role of tau in AD and other tauopathies, and highlight key issues that need to be addressed to improve the success of developing novel therapies.
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Affiliation(s)
- Rodrigo Medeiros
- Department of Neurobiology and Behavior and Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
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22
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Amyloid-beta and tau synergistically impair the oxidative phosphorylation system in triple transgenic Alzheimer's disease mice. Proc Natl Acad Sci U S A 2009; 106:20057-62. [PMID: 19897719 DOI: 10.1073/pnas.0905529106] [Citation(s) in RCA: 517] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by amyloid-beta (Abeta)-containing plaques, neurofibrillary tangles, and neuron and synapse loss. Tangle formation has been reproduced in P301L tau transgenic pR5 mice, whereas APP(sw)PS2(N141I) double-transgenic APP152 mice develop Abeta plaques. Cross-breeding generates triple transgenic ((triple)AD) mice that combine both pathologies in one model. To determine functional consequences of the combined Abeta and tau pathologies, we performed a proteomic analysis followed by functional validation. Specifically, we obtained vesicular preparations from (triple)AD mice, the parental strains, and nontransgenic mice, followed by the quantitative mass-tag labeling proteomic technique iTRAQ and mass spectrometry. Within 1,275 quantified proteins, we found a massive deregulation of 24 proteins, of which one-third were mitochondrial proteins mainly related to complexes I and IV of the oxidative phosphorylation system (OXPHOS). Notably, deregulation of complex I was tau dependent, whereas deregulation of complex IV was Abeta dependent, both at the protein and activity levels. Synergistic effects of Abeta and tau were evident in 8-month-old (triple)AD mice as only they showed a reduction of the mitochondrial membrane potential at this early age. At the age of 12 months, the strongest defects on OXPHOS, synthesis of ATP, and reactive oxygen species were exhibited in the (triple)AD mice, again emphasizing synergistic, age-associated effects of Abeta and tau in perishing mitochondria. Our study establishes a molecular link between Abeta and tau protein in AD pathology in vivo, illustrating the potential of quantitative proteomics.
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Takata K, Kitamura Y, Nakata Y, Matsuoka Y, Tomimoto H, Taniguchi T, Shimohama S. Involvement of WAVE accumulation in Abeta/APP pathology-dependent tangle modification in Alzheimer's disease. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:17-24. [PMID: 19497998 DOI: 10.2353/ajpath.2009.080908] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Synaptic deficits are closely correlated with cognitive dysfunction in Alzheimer's disease (AD), and synaptic integrity is regulated by the actin cytoskeleton. We demonstrated here that the Wiskott-Aldrich syndrome protein family verprolin-homologous protein (WAVE), a key molecule for actin assembly, co-aggregated with both hyperphosphorylated tau and phosphorylated collapsin response mediator protein 2 (CRMP2) in neurofibrillary tangles and abnormal neurites of the AD brain. Although phosphorylated CRMP2 accumulation was induced in the brains of JNPL3 mice, WAVE accumulation was not detected in the brains of either JNPL3 or Tg2576 mice that developed neurofibrillary tangles and amyloid-beta (Abeta) plaques, respectively. Interestingly, both phosphorylated CRMP2 accumulation and WAVE accumulation were recapitulated in the brains of 3xTg-AD mice that developed neurofibrillary tangles and Abeta plaques. In addition, we found an interaction between WAVE, CRMP2, and hyperphosphorylated tau in the cytosolic fraction of the AD brain. Taken together, WAVE accumulation may require both Abeta/amyloid precursor protein and tau pathologies, and an interaction between WAVE, CRMP2, and hyperphosphorylated tau may be involved in this process. Thus, WAVE accumulation may be involved in Abeta/amyloid precursor protein mediated-tangle modification, suggesting a possible correlation between WAVE accumulation and synaptic deficits induced by disturbances in actin assembly in AD brains.
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Affiliation(s)
- Kazuyuki Takata
- Department of Neurobiology and 21st Century COE Program, Kyoto Pharmaceutical University, Misasagi, Kyoto, Japan
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24
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The difference in gliosis induced by β-amyloid and Tau treatments in astrocyte cultures derived from senescence accelerated and normal mouse strains. Biogerontology 2009; 10:695-710. [DOI: 10.1007/s10522-009-9217-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 02/03/2009] [Indexed: 12/27/2022]
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Sotiropoulos I, Catania C, Riedemann T, Fry JP, Breen KC, Michaelidis TM, Almeida OFX. Glucocorticoids trigger Alzheimer disease-like pathobiochemistry in rat neuronal cells expressing human tau. J Neurochem 2008; 107:385-97. [PMID: 18691381 DOI: 10.1111/j.1471-4159.2008.05613.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Amyloid precursor protein (APP) mis-processing and aberrant tau hyperphosphorylation are causally related to the pathogenesis and neurodegenerative processes that characterize Alzheimer's disease (AD). Abnormal APP metabolism leads to the generation of neurotoxic amyloid beta (Abeta), whereas tau hyperphosphorylation culminates in cytoskeletal disturbances, neuronal dysfunction and death. Many AD patients hypersecrete glucocorticoids (GC) while neuronal structure, function and survival are adversely influenced by elevated GC levels. We report here that a rat neuronal cell line (PC12) engineered to express the human ortholog of the tau protein (PC12-htau) becomes more vulnerable to the toxic effects of either Abeta or GC treatment. Importantly, APP metabolism in GC-treated PC12-htau cells is selectively shifted towards increased production of the pro-amyloidogenic peptide C99. Further, GC treatment results in hyperphosphorylation of human tau at AD-relevant sites, through the cyclin-dependent kinase 5 (E.C. 2.7.11.26) and GSK3 (E.C. 2.7.11.22) protein kinases. Pulse-chase experiments revealed that GC treatment increased the stability of tau protein rather than its de novo synthesis. GC treatment also induced accumulation of transiently expressed EGFP-tau in the neuronal perikarya. Together with previous evidence showing that Abeta can activate cyclin-dependent kinase 5 and GSK3, these results uncover a potential mechanism through which GC may contribute to AD neuropathology.
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Wang JZ, Liu F. Microtubule-associated protein tau in development, degeneration and protection of neurons. Prog Neurobiol 2008; 85:148-75. [PMID: 18448228 DOI: 10.1016/j.pneurobio.2008.03.002] [Citation(s) in RCA: 286] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 12/29/2007] [Accepted: 03/13/2008] [Indexed: 12/11/2022]
Abstract
As a principal neuronal microtubule-associated protein, tau has been recognized to play major roles in promoting microtubule assembly and stabilizing the microtubules and to maintain the normal morphology of the neurons. Recent studies suggest that tau, upon alternative mRNA splicing and multiple posttranslational modifications, may participate in the regulations of intracellular signal transduction, development and viability of the neurons. Furthermore, tau gene mutations, aberrant mRNA splicing and abnormal posttranslational modifications, such as hyperphosphorylation, have also been found in a number of neurodegenerative disorders, collectively known as tauopathies. Therefore, changes in expression of the tau gene, alternative splicing of its mRNA and its posttranslational modification can modulate the normal architecture and functions of neurons as well as in a situation of tauopathies, such as Alzheimer's disease. The primary aim of this review is to summarize the latest developments and perspectives in our understanding about the roles of tau, especially hyperphosphorylation, in the development, degeneration and protection of neurons.
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Affiliation(s)
- Jian-Zhi Wang
- Pathophysiology Department, Hubei Provincial Key Laboratory of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China.
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Li Y, Liu T, Peng Y, Yuan C, Guo A. Specific functions of Drosophila amyloid precursor-like protein in the development of nervous system and nonneural tissues. ACTA ACUST UNITED AC 2005; 61:343-58. [PMID: 15389603 DOI: 10.1002/neu.20048] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Drosophila amyloid precursor-like protein (APPL) is expressed extensively in the nervous system soon after neuronal differentiation. By utilizing different transgenic flies, we studied the physiological function of two APPL protein forms, membrane-bound form (mAPPL) and secreted form (sAPPL), in neural development. We found that neither deletion nor overexpression of APPL protein altered the gross structure of mushroom bodies in the adult brain. No changes were detected in cell types and their relative ration in embryo-derived cultures from all APPL mutants. However, the neurite length was significantly increased in mutants overexpressing mAPPL. In addition, mutants lacking sAPPL had numerous neurite branches with abnormal lamellate membrane structures (LMSs) and blebs, while no apoptosis was detected in these neurons. The abnormal neurite morphology was most likely due to the disorganization of the cytoskeleton, as shown by double staining of actin filaments and microtubules. Electrophysiologically, A-type K+ current was significantly enhanced, and spontaneous excitatory postsynaptic potentials (sEPSPs) were greatly increased in APPL mutants lacking sAPPL. Moreover, panneural overexpression of different forms of APPL protein generated different defects of wings and cuticle in adult flies. Taken together, our results suggest that both mAPPL and sAPPL play essential roles in the development of the central nervous system and nonneural tissues.
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Affiliation(s)
- Yan Li
- Laboratory of Visual Information Processing, Center for Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, ChaoYang Dist., 15 DaTun Rd, Beijing 100101, People's Republic of China
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Schönheit B, Zarski R, Ohm TG. Spatial and temporal relationships between plaques and tangles in Alzheimer-pathology. Neurobiol Aging 2004; 25:697-711. [PMID: 15165691 DOI: 10.1016/j.neurobiolaging.2003.09.009] [Citation(s) in RCA: 180] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2002] [Revised: 07/29/2003] [Accepted: 09/17/2003] [Indexed: 11/17/2022]
Abstract
One histological hallmark in Alzheimer's disease is the tangle. The other is the plaque. A widely discussed hypothesis is the "amyloid cascade" assuming that tangle formation is a direct consequence of amyloid plaque formation. The aim of this study was to examine plaques and tangles in a highly defined neuronal circuitry in order to determine their detailed spatial and temporal relationships. We investigated serial sections of the whole hippocampal formation of brains with early Braak-stages (0-III) for tangles only, i.e. one case at stage 0, six at stage I, six at stage II, and nine at stage III. Most cases displayed both plaques and tangles. Four cases of stages 0 and I, three cases with stage II, and even one with stage III, however, did not display plaques. In turn, no plaque was found in the absence of tangles. The spatial relationship indicates that plaques lay in the terminal fields of tangle-bearing neurons. Our analysis suggests that tangles either antecede plaques or--less likely--are independently formed.
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Affiliation(s)
- Bärbel Schönheit
- Department of Clinical Cell and Neurobiology, Institute of Anatomy, Charité, 10098 Berlin, Germany
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Kovacs GG, Zerbi P, Voigtländer T, Strohschneider M, Trabattoni G, Hainfellner JA, Budka H. The prion protein in human neurodegenerative disorders. Neurosci Lett 2002; 329:269-72. [PMID: 12183028 DOI: 10.1016/s0304-3940(02)00668-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We evaluate cellular prion protein (PrP(C)) immunoreactivity (IR) in Alzheimer's, Parkinson's, diffuse Lewy body, and motor neuron diseases (MND), progressive supranuclear palsy, and multiple system atrophy. We use immunohistochemistry for PrP, including five monoclonal antibodies against different epitopes and three different pretreatments, alpha-synuclein, phosphorylated tau, beta-amyloid, and ubiquitin. Disease-specific inclusions are devoid of PrP(C) IR. Using double immunofluorescence and confocal laser microscopy we observe focal overlapping of PrP(C) with tau and with alpha-synuclein in early, but not in fully developed inclusions. However, PrP(C) IR neurons may contain abnormal tau or alpha-synuclein aggregates. Additionally, we observe a loss of PrP(C) IR in anterior horn neurons in MND. Our results suggest that expression of PrP(C) reflects a general response to cellular stress rather than specific co-operation in aggregation of other proteins.
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Affiliation(s)
- Gabor G Kovacs
- Institute of Neurology, University of Vienna, and Austrian Reference Centre for Human Prion Diseases, AKH 4J, Währinger Gürtel 18-20, PO Box 48, A-1097 Vienna, Austria
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30
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Torreilles F, Touchon J. Pathogenic theories and intrathecal analysis of the sporadic form of Alzheimer's disease. Prog Neurobiol 2002; 66:191-203. [PMID: 11943451 DOI: 10.1016/s0301-0082(01)00030-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Alzheimer's disease (AD) is an age-dependent dementia characterized by progressive loss of cognitive functions and by characteristic pathological changes in the brain: the formation of aggregates extracellularly by beta-amyloid (Abeta) peptide and intracellularly by tau proteins. The disease presents several major diagnostic difficulties: (1) AD develops slowly; (2) analysis of damaged brain tissues is difficult, requiring a biopsy which poses ethical problems; (3) no biochemical markers are available for the diagnosis and monitoring of the disease progression. Since the cerebrospinal fluid (CSF) is in contact with the extracellular space of the brain, many studies have tried to correlate the levels of the intrathecal peptides and amino acids and the development of dementia. The present review analyzes the main results of intrathecal content analyses in light of pathogenic theories proposed to explain the damage associated with AD and observed in the brain of patients by postmortem examination.
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Affiliation(s)
- François Torreilles
- CNRS UMR 5094, Institut de Biotechnologie et Pharmacologie, UFR Pharmacie, 15 Avenue Charles Flahault, 34093 Montpellier Cedex 5, France.
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31
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Hellström-Lindahl E. Modulation of beta-amyloid precursor protein processing and tau phosphorylation by acetylcholine receptors. Eur J Pharmacol 2000; 393:255-63. [PMID: 10771022 DOI: 10.1016/s0014-2999(00)00028-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Neurofibrillary lesions and senile plaques that are composed mainly of hyperphosphorylated tau protein and the amyloid-beta peptide derived from the amyloid precursor protein, respectively, are classical hallmarks of Alzheimer's disease. A number of studies strongly suggests that amyloid-beta formation and amyloid depositions are linked to the pathogenesis of Alzheimer's disease. Recent findings suggest that very low concentrations of the amyloid-beta can inhibit various cholinergic neurotransmitter functions independently of apparent neurotoxicity. Many factors have been shown to influence the processing of amyloid precursor protein, including activation of muscarinic and nicotinic receptors. This review focus on some recent studies concerning the regulation of amyloid precursor protein processing and modulation of tau phosphorylation by acetylcholine receptor stimulation and how cholinergic deficits and amyloid-beta might be related to one another.
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Affiliation(s)
- E Hellström-Lindahl
- Department of Clinical Neuroscience, Occupational Therapy and Elderly Care Research, Division of Molecular Neuropharmacology, Karolinska Institutet, Huddinge University Hospital, Sweden.
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32
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Grant SM, Morinville A, Maysinger D, Szyf M, Cuello AC. Phosphorylation of mitogen-activated protein kinase is altered in neuroectodermal cells overexpressing the human amyloid precursor protein 751 isoform. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1999; 72:115-20. [PMID: 10529469 DOI: 10.1016/s0169-328x(99)00157-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The aberrant expression or processing of the amyloid precursor protein (APP) is the only known genetic basis for presenile familial Alzheimer's disease, and the molecular connection between APP and tau has been perplexing. Attention has focused on proline-directed serine/threonine kinases as mediating the cytoskeletal modifications of Alzheimer's disease, and we show that overexpression of APP can influence the activation of a candidate kinase, the mitogen-activated protein kinase (MAPK). In murine embryonal carcinoma cells stably transfected with the human 751 isoform of APP, we observed steady-state hyperactivation of p42(MAPK) concomitant with APP overexpression 3 days after neuroectodermal differentiation. In more mature differentiated cells, immunocytochemical analysis revealed enhanced basal somatic and nuclear immunoreactivity for phosphorylated MAPK coupled with an attenuated phosphorylation response to growth factor stimulation. Our results suggest that APP can influence the MAPK signaling pathway in such a way that the absolute and time-dependent activation required for discrimination of the appropriate downstream response are compromised. Such an effect would have important consequences for the functioning of cells coincidentally expressing both proteins, a situation that occurs in neuronal populations vulnerable to Alzheimer's disease pathology.
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Affiliation(s)
- S M Grant
- Department of Pharmacology and Therapeutics, McGill University, 3655 Drummond Street, Room 1325, Montreal, QC, Canada
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33
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Torroja L, Chu H, Kotovsky I, White K. Neuronal overexpression of APPL, the Drosophila homologue of the amyloid precursor protein (APP), disrupts axonal transport. Curr Biol 1999; 9:489-92. [PMID: 10322116 DOI: 10.1016/s0960-9822(99)80215-2] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The two pathological hallmarks of Alzheimer's disease, amyloid plaques and neurofibrillary tangles, involve two apparently unrelated proteins, the amyloid precursor protein (APP) and Tau. Although it is known that aberrant processing of APP is associated with Alzheimer's disease, the definitive role of APP in neurons is not yet clear. Tau regulates microtubule stabilization and assembly in axons and is, thus, an essential component of the microtubule-associated organelle transport machinery. Although several groups have reported physical interaction between APP and Tau, and induction of Tau phosphorylation by APP and beta-amyloid peptide, the functional connection between APP and Tau is unclear. To explore the possibility that the functions of these two proteins may somehow converge on the same cellular process, we overexpressed APPL, the Drosophila homologue of APP, along with Tau in Drosophila neurons. Panneural coexpression of APPL and Tau resulted in adults that, upon eclosion, failed to expand wings and harden the cuticle, which is suggestive of neuroendocrine dysfunction. We analyzed axonal transport when Tau and APPL were coexpressed and found that transport of axonal cargo was disrupted, as evidenced by increased retention of synaptic proteins in axons and scarcity of neuropeptide-containing vesicles in the distal processes of peptidergic neurons. In an independent approach, we demonstrated genetic interaction and phenotypic similarity between APPL overexpression and mutations in the Kinesin heavy chain (Khc) gene, the product of which is a motor for anterograde vesicle trafficking.
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Affiliation(s)
- L Torroja
- Department of Biology, Center for Complex Systems, MS 008, Brandeis University Waltham, Massachusetts, 02454, USA
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34
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Jung SS, Gauthier S, Cashman NR. Beta-amyloid precursor protein is detectable on monocytes and is increased in Alzheimer's disease. Neurobiol Aging 1999; 20:249-57. [PMID: 10588572 DOI: 10.1016/s0197-4580(99)00051-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Using the anti-beta-amyloid precursor protein (betaAPP) monoclonal antibodies 4G8, 6E10 and 22C11 and flow cytometry, we report that human circulating peripheral blood monocytes display surface immunoreactivity for betaAPP. In contrast, circulating lymphocytes do not possess cell surface betaAPP immunoreactivity, despite similar levels of betaAPP expression. Immunoblotting analysis showed that monocytes, but not lymphocytes, possess an 82 kDa C-terminal betaAPP fragment consistent with a processed transmembrane species. Monocyte surface betaAPP was upregulated approximately threefold by activation with lipopolysaccharide and interferon-gamma, activation did not produce detectable betaAPP on the cell surface of lymphocytes. Surface betaAPP immunoreactivity was reduced in a normal aged population compared to normal young controls (Young = 81.07 +/- 13.67 mean fluorescence units, Aged = 36.74 +/- 3.81, p < 0.01), but was significantly increased in AD subjects compared to age-matched healthy controls (AD = 60.31 +/- 7.42, p < 0.05). Our data suggest that a proportion of peripheral A beta may be derived from monocyte/macrophages, and that defects in brain cell processing of betaAPP in AD may be shared by this readily accessible peripheral cell.
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Affiliation(s)
- S S Jung
- Department of Microbiology & Immunology, Montréal Neurological Institute, McGill University, PQ, Canada
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35
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Marcon G, Giaccone G, Canciani B, Cajola L, Rossi G, De Gioia L, Salmona M, Bugiani O, Tagliavini F. A betaPP peptide carboxyl-terminal to Abeta is neurotoxic. THE AMERICAN JOURNAL OF PATHOLOGY 1999; 154:1001-7. [PMID: 10233838 PMCID: PMC1866553 DOI: 10.1016/s0002-9440(10)65352-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/23/1998] [Indexed: 11/21/2022]
Abstract
Extracellular Abeta-amyloid and intraneuronal paired helical filaments (PHFs) composed of tau protein are the neuropathological hallmark of Alzheimer's disease. Abeta is a 39- to 43-residue peptide derived by cleavage of a 695- to 770-amino-acid membrane-associate glycoprotein (termed beta-protein precursor, betaPP). Following the observation that an antiserum to an epitope located between residues 713 and 723 of betaPP770 (ie, the transmembrane region of the betaPP distal to Abeta) labels PHFs and that a synthetic peptide homologous to residues 713 to 730 of betaPP770 (betaPP713-730) is highly fibrillogenic and interacts with tau in vitro, it has been hypothesized that betaPP fragments other than Abeta may feature in the pathogenesis of Alzheimer's disease concurring with neuronal degeneration. To investigate this issue, we have analyzed the effects of the exposure of primary neuronal cultures to the synthetic peptide betaPP713-730. Cultures were prepared from rat hippocampus on embryonic day 17 and incubated with the peptide at 2.5 to 30 micromol/L concentration for 1 to 4 days. Cell viability was compared with that of control cultures exposed to a scrambled sequence of the peptide. A 4-day exposure to 20 micromol/L betaPP713-730 resulted in almost complete neuronal loss, whereas no changes were observed with the scrambled peptide. Degenerating neurons showed DNA fragmentation by agarose gel electrophoresis and apoptotic changes by light and electron microscopy. These findings support the view that betaPP sequences other than Abeta may play a role in nerve cell degeneration in Alzheimer's disease.
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Affiliation(s)
- G Marcon
- Division of Neuropathology, Istituto Nazionale Neurologico Carlo Besta, Italy
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36
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Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder with a deadly outcome. AD is the leading cause of senile dementia and although the pathogenesis of this disorder is not known, various hypotheses have been developed based on experimental data accumulated since the initial description of this disease by Alois Alzheimer about 90 years ago. Most approaches to explain the pathogenesis of AD focus on its two histopathological hallmarks, the amyloid beta protein- (A(beta)-) loaded senile plaques and the neurofibrillary tangles, which consist of the filament protein tau. Various lines of genetic evidence support a central role of A(beta) in the pathogenesis of AD and an increasing number of studies show that oxidation reactions occur in AD and that A(beta) may be one molecular link between oxidative stress and AD-associated neuronal cell death. A(beta) itself can be neurotoxic and can induce oxidative stress in cultivated neurons. A(beta) is, therefore, one player in the concert of oxidative reactions that challenge neurons besides inflammatory reactions which are also associated with the AD pathology. Consequently, antioxidant approaches for the prevention and therapy of AD are of central interest. Experimental as well as clinical data show that lipophilic antioxidants, such as vitamin E and estrogens, are neuroprotective and may help patients suffering from AD. While an additional intensive elucidation of the cellular and molecular events of neuronal cell death in AD will, ultimately, lead to novel drug targets, various antioxidants are already available for a further exploitation of their preventive and therapeutic potential. reserved
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Affiliation(s)
- C Behl
- Max Planck Institute of Psychiatry, Munich, Germany.
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37
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Smith MA, Perry G. What are the facts and artifacts of the pathogenesis and etiology of Alzheimer disease? J Chem Neuroanat 1998; 16:35-41. [PMID: 9924971 DOI: 10.1016/s0891-0618(98)00061-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Over the past decade, an increased clinical awareness, together with advances in biochemical, cellular, and molecular analyses, have catapulted the study of Alzheimer disease to the forefront of biomedical research. During this time, a great number of theories, regarding disease pathogenesis, have come and gone but several have persisted. Here, we critically evaluate these theories in an attempt to delineate the facts from the artifacts.
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Affiliation(s)
- M A Smith
- Case Western Reserve University, Institute of Pathology, Cleveland, OH 44106, USA
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38
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Ohshita T, Nakatani A, Hiroi Y. Purification by column chromatographies of beta-amyloid precursor proteins and their association with other 95 kDa protein in rat brain. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 1998; 716:107-18. [PMID: 9824223 DOI: 10.1016/s0378-4347(98)00320-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Beta-amyloid precursor proteins (APPs) in the subcellular fractions of the homogenate of rat brain were detected immunologically. They were found to be localized in both the cytosol and microsome fractions in generally equal amounts. APPs were purified from the cytosol fraction of rat brain by column chromatography in a DEAE-anion-exchanger, Blue-Sepharose, Ni-charged chelating Sepharose, and Sephacryl S-300 columns. They migrated at about 400 kDa or above in a final gel filtration column with trypsin inhibitor activity. They gave two broad protein bands of 80 and 100 kDa and several other protein bands in sodium dodecyl sulfate-polyacryl amide gel electrophoresis (SDS-PAGE). The 80 and 100 kDa bands were highly concentrated during purification. They gave the same amino terminal sequence and were identified as rat APPs without an amino terminal signal sequence. These results suggest that rat brain APPs form a complex with themselves or with other proteins and contain APP isoforms including a serine protease inhibitor domain, APP770 or APP751, or both. An antibody produced by a rabbit immunized with the final preparation of APPs reacted with a 95 kDa protein band which migrated between the 80 and 100 kDa bands of APPs in SDS-PAGE, but it did not react with the bands of APPs. The 80 and 100 kDa APP bands were coprecipitated with a 95 kDa antigen protein band by reacting this antibody with the partially purified APPs. We conclude that APPs in the rat brain are associated directly or indirectly with another protein to yield the 95 kDa band demonstrated by SDS-PAGE.
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Affiliation(s)
- T Ohshita
- School of Food and Nutrition, Shokei Junior College, Kumamoto, Japan
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39
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Affiliation(s)
- M A Smith
- Institute of Pathology, Case Western Reserve University, Cleveland, Ohio 44106, USA
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40
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Smith MA, Harris PL, Sayre LM, Perry G. Iron accumulation in Alzheimer disease is a source of redox-generated free radicals. Proc Natl Acad Sci U S A 1997; 94:9866-8. [PMID: 9275217 PMCID: PMC23283 DOI: 10.1073/pnas.94.18.9866] [Citation(s) in RCA: 942] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Damage from free radicals has been demonstrated in susceptible neuronal populations in cases of Alzheimer disease. In this study, we investigated whether iron, a potent source of the highly reactive hydroxyl radical that is generated by the Fenton reaction with H2O2, might contribute to the source of radicals in Alzheimer disease. We found, using a modified histochemical technique that relies on the formation of mixed valence iron complexes, that redox-active iron is associated with the senile plaques and neurofibrillary tangles-the pathological hallmark lesions of this disease. This lesion-associated iron is able to participate in in situ oxidation and readily catalyzes an H2O2-dependent oxidation. Furthermore, removal of iron was completely effected using deferoxamine, after which iron could be rebound to the lesions. Characterization of the iron-binding site suggests that binding is dependent on available histidine residues and on protein conformation. Taken together, these findings indicate that iron accumulation could be an important contributor toward the oxidative damage of Alzheimer disease.
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Affiliation(s)
- M A Smith
- Institute of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA.
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41
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Paik SR, Lee JH, Kim DH, Chang CS, Kim J. Aluminum-induced structural alterations of the precursor of the non-A beta component of Alzheimer's disease amyloid. Arch Biochem Biophys 1997; 344:325-34. [PMID: 9264546 DOI: 10.1006/abbi.1997.0207] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The precursor of the non-A beta component of Alzheimer's disease amyloid (NACP) is a presynaptic protein whose function has been suspected to be tightly involved in neuronal biogenesis including synaptic regulations. NACP was suggested to seed the neuritic plaque formation in the presence of A beta during the development of Alzheimer's disease (AD). Recombinant NACP purified through heat treatment, DEAE-Sephacel anion-exchange, Sephacryl S-200 size-exclusion, and S-Sepharose cation-exchange chromatography steps appeared as a single band on SDS-PAGE with Mr of 19 kDa. Its N-terminal amino acid sequence clearly confirmed that the protein was NACP. Interestingly, however, the protein was split into a doublet on a nondenaturing (ND)-PAGE with equal intensities. The doublet was located slightly above a 45-kDa marker protein on a 12.5% ND-PAGE. In addition, the size of NACP was more carefully estimated as 53 kDa with high-performance gel-permeation chromatography using a TSK G3000sw size-exclusion column. Recently, Lansbury and his colleagues (Biochemistry 35, 13709-13715) have reported that NACP exists as an elongated "natively unfolded" structure which would make the protein more actively involved in protein-protein interactions and Kim (Mol. Cells 7, 78-83) has also shown that the natively unfolded protein is extremely sensitive to proteases. Here, we report that the structure of NACP could be altered by certain environmental factors. Aluminum, a suspected risk factor for AD, converged the doublet of NACP into a singlet with slightly lower mobility on ND-PAGE. Spectroscopic analysis employing uv absorption, intrinsic fluorescence, and circular dichroism indicated that NACP experienced the structural alterations in the presence of aluminum such as the secondary structure transition to generate about 33% alpha-helix. This altered structure of NACP became resistant to proteases such as trypsin, alpha-chymotrypsin, and calpain. Therefore, it is suggested that aluminum, which influences two pathologically critical processes in AD such as the protein turnover and the protein aggregation via the structural modifications, could participate in the disease.
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Affiliation(s)
- S R Paik
- Department of Biochemistry, College of Medicine, Inha University, Nam-Ku, Inchon, Korea.
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42
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Henry A, Masters CL, Beyreuther K, Cappai R. Expression of human amyloid precursor protein ectodomains in Pichia pastoris: analysis of culture conditions, purification, and characterization. Protein Expr Purif 1997; 10:283-91. [PMID: 9226725 DOI: 10.1006/prep.1997.0748] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have examined the use of the yeast Pichia pastoris for expression of the human amyloid precursor protein (APP). The ectodomains of the isoforms APP695, APP751, and APP770 were expressed in both P. pastoris protease-deficient strain SMD1163 and wild-type strain GS115, using the secretion vector pHIL-S1. Expression of recombinant APP in each of these strains produced intact recombinant protein, together with a small number of breakdown products. The levels of these breakdown products were not significantly altered by expression in the protease-deficient strain compared with wild-type GS115. The effects of induction time and medium composition on recombinant APP stability were also examined. After optimization of expression and culture conditions, baffled shaker flask cultures of clones selected for high expression routinely yielded 13-24 mg/liter recombinant protein following a two-step purification procedure. The recombinant isoforms possessed the heparin binding, metal binding, and Kunitz-type protease inhibitor properties of human brain-derived APP. These data indicate that P. pastoris is an appropriate laboratory-scale expression system for production of sufficient quantities of recombinant APP for use in biological studies.
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Affiliation(s)
- A Henry
- Department of Pathology, University of Melbourne, Parkville, Victoria, Australia
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43
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Seilheimer B, Bohrmann B, Bondolfi L, Müller F, Stüber D, Döbeli H. The toxicity of the Alzheimer's beta-amyloid peptide correlates with a distinct fiber morphology. J Struct Biol 1997; 119:59-71. [PMID: 9216088 DOI: 10.1006/jsbi.1997.3859] [Citation(s) in RCA: 187] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In an attempt to elucidate the relationship among aggregation properties, fiber morphology, and cellular toxicity several beta-amyloid peptides (A beta) were prepared according to a standardized procedure. Peptides either carried mutations inside the membrane anchor segment around amino acid position 35 or their carboxy terminus was shortened from 42 to 41, 40, or 39 amino acids. The time-dependent self-assembly of monomeric A beta into fibers was simultaneously monitored by electron microscopy, circular dichroism spectroscopy, analytical ultracentrifugation, and A beta-mediated cellular toxicity using the reduction of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) to measure cell viability. The transition of A beta monomers into fibers was analyzed by more than 600 electron micrographs. Distinct morphological changes from seed-like structures to immature and mature fibers were observed. Seeds were of spherical appearance. Immature fibers were typically elongated structures with a rough surface and with varying thickness depending on the A beta sequence. Mature fibers were characterized by a periodic variation of their thickness along the fiber axis. The proportion of these different structures and the total amount of aggregated A beta was amino acid sequence-dependent. Wild-type A beta 1-42 and its oxidized derivative carrying a methionine sulfoxide residue at position 35 showed the highest rate of fiber formation and exerted toxic activity in the MTT assay at very low nanomolar concentrations. The fibers formed by these two peptides were predominantly of the mature type. In contrast, carboxyl-terminus truncated peptides A beta 1-41, A beta 1-40, and A beta 1-39 or most A beta 1-42 derivatives mutated around amino acid position 35 showed a reduced aggregation rate, the immature fibers predominated, and the toxicity was orders of magnitude lower. Thus, a correlation can be drawn among the chemical structure, aggregation properties, fiber morphology, and cellular toxicity.
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44
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Delacourte A, Buée L. Normal and pathological Tau proteins as factors for microtubule assembly. INTERNATIONAL REVIEW OF CYTOLOGY 1997; 171:167-224. [PMID: 9066128 DOI: 10.1016/s0074-7696(08)62588-7] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Tau proteins are microtubule-associated proteins. They regulate the dynamics of the microtubule network, especially involved in the axonal transport and neuronal plasticity. Tau proteins belong to a family of developmentally regulated isoforms generated by alternative splicing and phosphorylation. This generates several Tau variants that interact with tubulin and other proteins. Therefore, Tau proteins are influenced by many physiological regulations. Tau proteins are also powerful markers of the neuronal physiological state. Their degree of phosphorylation is a good marker of cell integrity. It is heavily disturbed in numerous neurodegenerative disorders, leading to a collapse of the microtubule network and the presence of intraneuronal lesions resulting from Tau aggregation. However, different biochemical and immunological patterns of pathological Tau proteins found among neurodegenerative disorders are useful markers for the understanding of the role of Tau protein isoforms and the diagnosis of these pathological conditions.
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45
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46
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Philippe B, Brion JP, Coppens E, Octave JN. Generation of a monoclonal antibody to the carboxy-terminal domain of tau by immunization with the amino-terminal domain of the amyloid precursor protein. J Neurosci Res 1996; 46:709-19. [PMID: 8978505 DOI: 10.1002/jnr.490460602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A fusion protein between beta-galactosidase and the amino-terminal domain of amyloid precursor protein (APP) was used as an immunogen for the production of monoclonal antibodies. One of these antibodies, the 5D12 monoclonal antibody, labeled the neurofibrillary tangles (NFT) by immunohistochemistry, as well as isolated paired helical filaments (PHF) in electron microscopy. In immunoassay, the ascitic fluid produced by the 5D12 clone was demonstrated to contain a high titer of antibodies to heat-stable microtubule associated proteins (MAPs). By immunoblotting, the proteins recognized in heat-stable MAPs were found to correspond to tau proteins. The 5D12 antibody recognized normal tau isolated from rat and human brain homogenates, and PHF-tau isolated from the brain of patients with Alzheimer's disease (AD). By immunoblotting, the 5D12 antibody also recognized the full-length recombinant tau protein but not the fusion protein used as an immunogen. The immunoreactivity of the 5D12 antibody with tau was completely abolished when the half-carboxy domain of tau, containing the tubulin-binding repeats, was removed. This study demonstrates that the use of the amino-terminal domain of APP as an immunogen led to the generation of a monoclonal antibody to the half-carboxy domain of tau.
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Affiliation(s)
- B Philippe
- Laboratoire de Neurochimie, Université Catholique de Louvain, Brussels, Belgium
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47
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Blennow K, Cowburn RF. The neurochemistry of Alzheimer's disease. ACTA NEUROLOGICA SCANDINAVICA. SUPPLEMENTUM 1996; 168:77-86. [PMID: 8997425 DOI: 10.1111/j.1600-0404.1996.tb00378.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The last 15-20 years have seen a wealth of studies to characterize the neurochemical abnormalities of Alzheimer's disease, in particular those involving the beta-amyloid and tau proteins, as well as more recently, apolipoprotein E4. This article provides a summary of the evidence for the involvement of these proteins in Alzheimer's disease pathogenesis based on postmortem brain and CSF studies.
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Affiliation(s)
- K Blennow
- Department of Clinical Neuroscience, University of Göteborg, Mölndal Hospital, Sweden
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48
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Jung SS, Nalbantoglu J, Cashman NR. Alzheimer's beta-amyloid precursor protein is expressed on the surface of immediately ex vivo brain cells: a flow cytometric study. J Neurosci Res 1996; 46:336-48. [PMID: 8933373 DOI: 10.1002/(sici)1097-4547(19961101)46:3<336::aid-jnr7>3.0.co;2-l] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Beta-amyloid precursor protein (beta APP) is ubiquitously expressed, but deposition of the beta APP proteolytic fragment A beta is virtually restricted to the brain, suggesting cell-specific processing of this molecule. Our laboratory has investigated expression of beta APP in mechanically dissociated, unfixed, immediately ex vivo cells from various mouse and rat organs by flow cytometry. Epitopes of predicted extracellular domains of beta APP recognized by the N-terminal 22C11 monoclonal antibody (mAb) and the juxtamembrane 4G8 mAb were not detectable on the surface of lymphoid cells, hepatocytes, or kidney cells. In contrast, surface 22C11 and 4G8 beta APP immunoreactivity was abundant on intact (propidium iodide-excluding) dissociated brain cells. The predicted C-terminal intracellular beta APP determinant recognized by the mAb Jonas was not detectable on the surface of intact brain cells, but was present in ethanol-permeabilized cells, consistent with a transmembrane configuration of beta APP in brain cells. Trypsinization of intact brain cells abolished cell surface immunoreactivity for 22C11, which was then reestablished by short-term culture. Augmentation of 22C11 and 4G8 surface immunoreactivity occurred when brain cells were cultured short-term in phenylarsine oxide, a general endocytosis inhibitor. By double staining protocols of brain cells with mAbs directed against beta APP ectodomain epitopes and the neuronal surface proteins Thy-1 or neural cell adhesion molecule (NCAM), we observed that all Thy-1+ and NCAM+ cells (approximately 50%) were immunoreactive for surface beta APP, but that some beta APP+ cells (approximately 20%) were negative for these neuronal markers. Our data suggest that neurons and a subpopulation of other brain cells, unlike peripheral cells, can support beta APP as a type 1 intrinsic membrane molecule with an intact ectodomain, and that beta APP surface abundance is regulated by an equilibrium between membranes vesicle insertion and endocytotic internalization. Transmembrane beta APP holoprotein may be a critical determinant of brain-predominant processing of beta APP to A beta, and may participate in a receptor/transducer function unique to brain cells.
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Affiliation(s)
- S S Jung
- Department of Microbiology and Immunology, McGill University, Montréal Neurological Institute, Canada
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49
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Forloni G, Tagliavini F, Bugiani O, Salmona M. Amyloid in Alzheimer's disease and prion-related encephalopathies: studies with synthetic peptides. Prog Neurobiol 1996; 49:287-315. [PMID: 8888112 DOI: 10.1016/0301-0082(96)00013-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Deposition of amyloid-beta protein (beta A) in brain parenchyma and vessel walls is a major pathological feature of Alzheimer's disease (AD). In prion-related encephalopathies (PRE), too, an altered form of prion protein (PrPsc) forms amyloid fibrils and accumulates in the brain. In both conditions the amyloid deposition is accompanied by nerve cell loss, whose pathogenesis and molecular basis are not understood. Neuropathological, genetic and biochemical studies indicate a central role of beta A in the AD pathogenesis. Synthetic peptides homologous to beta A and its fragments contribute to investigate the mechanisms of beta A deposit formation and the role played by beta A in AD pathogenesis. The physicochemical studies on the beta-sheet conformation and self-aggregation properties of beta A peptides indicate the conditions and the factors influencing the formation of beta A deposits. The neurotoxic activity of beta A and its fragments support the causal relationship between beta A deposits and the neuropathological events in AD. Numerous studies were performed to clarify the mechanism of neuronal death induced by exposure to beta A peptides. A similar approach has been used to investigate the role of PrPsc in PRE; in these diseases, the association between accumulation of PrPsc and neuropathology is evident and numerous data indicate that PrPsc itself might be the infectious agent responsible for disease transmission. Thus, PrP peptides were used to investigate the pathogenic role of PrPsc in PRE and the conformational change responsible for the conversion PrPc to PrPsc that makes the molecule apparently infectious. In particular, we synthesized a peptide homologous to residues 106-126, an integral part of all abnormal PrP isoforms that accumulate in the brain of subjects' PRE. This peptide is fibrillogenic, has secondary structure largely composed of beta-sheet and proteinase-resistant properties, is neurotoxic and induces astrogliosis. In this review, we summarize and compare the data obtained with beta A and PrP peptides and analyze the significance in terms of amyloidogenic proteins and neurodegeneration.
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Affiliation(s)
- G Forloni
- Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
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50
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Smith MA, Sayre LM, Monnier VM, Perry G. Oxidative posttranslational modifications in Alzheimer disease. A possible pathogenic role in the formation of senile plaques and neurofibrillary tangles. MOLECULAR AND CHEMICAL NEUROPATHOLOGY 1996; 28:41-8. [PMID: 8871940 DOI: 10.1007/bf02815203] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The distinctive pathological lesions of Alzheimer disease (AD), senile plaques, and neurofibrillary tangles comprise aggregates of insoluble fibrillar protein. We and other investigators recently demonstrated that several mechanisms related to oxidative stress and free-radical reactions could play a crucial role in the pathogenesis of AD and, specifically, in the formation of senile plaques and neurofibrillary tangles (NFT).
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Affiliation(s)
- M A Smith
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
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