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Mangiafico SP, Tuo QZ, Li XL, Liu Y, Haralambous C, Ding XL, Ayton S, Wang Q, Laybutt DR, Chan JY, Zhang X, Kos C, Thomas HE, Loudovaris T, Yang CH, Joannides CN, Lamont BJ, Dai L, He HH, Dong B, Andrikopoulos S, Bush AI, Lei P. Tau suppresses microtubule-regulated pancreatic insulin secretion. Mol Psychiatry 2023; 28:3982-3993. [PMID: 37735502 DOI: 10.1038/s41380-023-02267-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 09/05/2023] [Accepted: 09/11/2023] [Indexed: 09/23/2023]
Abstract
Tau protein is implicated in the pathogenesis of Alzheimer's disease (AD) and other tauopathies, but its physiological function is in debate. Mostly explored in the brain, tau is also expressed in the pancreas. We further explored the mechanism of tau's involvement in the regulation of glucose-stimulated insulin secretion (GSIS) in islet β-cells, and established a potential relationship between type 2 diabetes mellitus (T2DM) and AD. We demonstrate that pancreatic tau is crucial for insulin secretion regulation and glucose homeostasis. Tau levels were found to be elevated in β-islet cells of patients with T2DM, and loss of tau enhanced insulin secretion in cell lines, drosophila, and mice. Pharmacological or genetic suppression of tau in the db/db diabetic mouse model normalized glucose levels by promoting insulin secretion and was recapitulated by pharmacological inhibition of microtubule assembly. Clinical studies further showed that serum tau protein was positively correlated with blood glucose levels in healthy controls, which was lost in AD. These findings present tau as a common therapeutic target between AD and T2DM.
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Affiliation(s)
- Salvatore P Mangiafico
- Department of Medicine, Austin Hospital, University of Melbourne, Heidelberg, VIC, 3084, Australia
| | - Qing-Zhang Tuo
- Department of Neurology and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Xiao-Lan Li
- Department of Neurology and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Yu Liu
- Department of Neurology and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Christian Haralambous
- Department of Medicine, Austin Hospital, University of Melbourne, Heidelberg, VIC, 3084, Australia
| | - Xu-Long Ding
- Department of Neurology and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Scott Ayton
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
| | - Qing Wang
- Department of Neurology and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - D Ross Laybutt
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, NSW, 2010, Australia
| | - Jeng Yie Chan
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, St Vincent's Hospital, Sydney, NSW, 2010, Australia
| | - Xiang Zhang
- Department of Neurology and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Cameron Kos
- St. Vincent's Institute of Medical Research and Department of Medicine, St. Vincent's Hospital, The University of Melbourne, Fitzroy, VIC, 3065, Australia
| | - Helen E Thomas
- St. Vincent's Institute of Medical Research and Department of Medicine, St. Vincent's Hospital, The University of Melbourne, Fitzroy, VIC, 3065, Australia
| | - Thomas Loudovaris
- St. Vincent's Institute of Medical Research and Department of Medicine, St. Vincent's Hospital, The University of Melbourne, Fitzroy, VIC, 3065, Australia
- Institute for Cellular Transplantation, Department of Surgery, College of Medicine, University of Arizona, Tucson, AZ, 85724-5066, USA
| | - Chieh-Hsin Yang
- Department of Medicine, Austin Hospital, University of Melbourne, Heidelberg, VIC, 3084, Australia
| | - Christos N Joannides
- Department of Medicine, Austin Hospital, University of Melbourne, Heidelberg, VIC, 3084, Australia
| | - Benjamin J Lamont
- Department of Medicine, Austin Hospital, University of Melbourne, Heidelberg, VIC, 3084, Australia
| | - Lunzhi Dai
- Department of Neurology and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Hai-Huai He
- Department of Neurology and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Biao Dong
- Department of Neurology and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China
| | - Sofianos Andrikopoulos
- Department of Medicine, Austin Hospital, University of Melbourne, Heidelberg, VIC, 3084, Australia.
| | - Ashley I Bush
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia.
| | - Peng Lei
- Department of Neurology and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, 610041, China.
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia.
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Law AD, Cassar M, Long DM, Chow ES, Giebultowicz JM, Venkataramanan A, Strauss R, Kretzschmar D. FTD-associated mutations in Tau result in a combination of dominant and recessive phenotypes. Neurobiol Dis 2022; 170:105770. [PMID: 35588988 PMCID: PMC9261467 DOI: 10.1016/j.nbd.2022.105770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 04/29/2022] [Accepted: 05/11/2022] [Indexed: 11/26/2022] Open
Abstract
Although mutations in the microtubules-associated protein Tau have long been connected with several neurodegenerative diseases, the underlying molecular mechanisms causing these tauopathies are still not fully understood. Studies in various models suggested that dominant gain-of-function effects underlie the pathogenicity of these mutants; however, there is also evidence that the loss of normal physiological functions of Tau plays a role in tauopathies. Previous studies on Tau in Drosophila involved expressing the human Tau protein in the background of the endogenous Tau gene in addition to inducing high expression levels. To study Tau pathology in more physiological conditions, we recently created Drosophila knock-in models that express either wildtype human Tau (hTauWT) or disease-associated mutant hTau (hTauV337M and hTauK369I) in place of the endogenous Drosophila Tau (dTau). Analyzing these flies as homozygotes, we could therefore detect recessive effects of the mutations while identifying dominant effects in heterozygotes. Using memory, locomotion and sleep assays, we found that homozygous mutant hTau flies showed deficits already when quite young whereas in heterozygous flies, disease phenotypes developed with aging. Homozygotes also revealed an increase in microtubule diameter, suggesting that changes in the cytoskeleton underlie the axonal degeneration we observed in these flies. In contrast, heterozygous mutant hTau flies showed abnormal axonal targeting and no detectable changes in microtubules. However, we previously showed that heterozygosity for hTauV337M interfered with synaptic homeostasis in central pacemaker neurons and we now show that heterozygous hTauK369I flies have decreased levels of proteins involved in the release of synaptic vesicles. Taken together, our results demonstrate that both mutations induce a combination of dominant and recessive disease-related phenotypes that provide behavioral and molecular insights into the etiology of Tauopathies.
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Affiliation(s)
- Alexander D Law
- Oregon Institute of Occupational Health Sciences, 3181 S.W. Sam Jackson Park Road, Portland, OR 97219, USA
| | - Marlène Cassar
- Oregon Institute of Occupational Health Sciences, 3181 S.W. Sam Jackson Park Road, Portland, OR 97219, USA
| | - Dani M Long
- Oregon Institute of Occupational Health Sciences, 3181 S.W. Sam Jackson Park Road, Portland, OR 97219, USA
| | - Eileen S Chow
- Department of Integrative Biology, Oregon State University, Corvallis, OR 97331, USA
| | | | - Anjana Venkataramanan
- Institut für Entwicklungsbiologie und Neurobiologie, Johannes Gutenberg-Universität Mainz, Hanns-Dieter-Hüsch Weg 15, 55128 Mainz, Germany
| | - Roland Strauss
- Institut für Entwicklungsbiologie und Neurobiologie, Johannes Gutenberg-Universität Mainz, Hanns-Dieter-Hüsch Weg 15, 55128 Mainz, Germany
| | - Doris Kretzschmar
- Oregon Institute of Occupational Health Sciences, 3181 S.W. Sam Jackson Park Road, Portland, OR 97219, USA.
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Lei P, Ayton S, Bush AI. The essential elements of Alzheimer's disease. J Biol Chem 2020; 296:100105. [PMID: 33219130 PMCID: PMC7948403 DOI: 10.1074/jbc.rev120.008207] [Citation(s) in RCA: 127] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 11/19/2020] [Accepted: 11/20/2020] [Indexed: 02/05/2023] Open
Abstract
Treatments for Alzheimer’s disease (AD) directed against the prominent amyloid plaque neuropathology are yet to be proved effective despite many phase 3 clinical trials. There are several other neurochemical abnormalities that occur in the AD brain that warrant renewed emphasis as potential therapeutic targets for this disease. Among those are the elementomic signatures of iron, copper, zinc, and selenium. Here, we review these essential elements of AD for their broad potential to contribute to Alzheimer’s pathophysiology, and we also highlight more recent attempts to translate these findings into therapeutics. A reinspection of large bodies of discovery in the AD field, such as this, may inspire new thinking about pathogenesis and therapeutic targets.
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Affiliation(s)
- Peng Lei
- Department of Neurology and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, P.R. China; Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.
| | - Scott Ayton
- Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Ashley I Bush
- Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia.
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Kent SA, Spires-Jones TL, Durrant CS. The physiological roles of tau and Aβ: implications for Alzheimer's disease pathology and therapeutics. Acta Neuropathol 2020; 140:417-447. [PMID: 32728795 PMCID: PMC7498448 DOI: 10.1007/s00401-020-02196-w] [Citation(s) in RCA: 197] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/20/2020] [Accepted: 07/20/2020] [Indexed: 01/18/2023]
Abstract
Tau and amyloid beta (Aβ) are the prime suspects for driving pathology in Alzheimer's disease (AD) and, as such, have become the focus of therapeutic development. Recent research, however, shows that these proteins have been highly conserved throughout evolution and may have crucial, physiological roles. Such functions may be lost during AD progression or be unintentionally disrupted by tau- or Aβ-targeting therapies. Tau has been revealed to be more than a simple stabiliser of microtubules, reported to play a role in a range of biological processes including myelination, glucose metabolism, axonal transport, microtubule dynamics, iron homeostasis, neurogenesis, motor function, learning and memory, neuronal excitability, and DNA protection. Aβ is similarly multifunctional, and is proposed to regulate learning and memory, angiogenesis, neurogenesis, repair leaks in the blood-brain barrier, promote recovery from injury, and act as an antimicrobial peptide and tumour suppressor. This review will discuss potential physiological roles of tau and Aβ, highlighting how changes to these functions may contribute to pathology, as well as the implications for therapeutic development. We propose that a balanced consideration of both the physiological and pathological roles of tau and Aβ will be essential for the design of safe and effective therapeutics.
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Affiliation(s)
- Sarah A. Kent
- Translational Neuroscience PhD Programme, Centre for Discovery Brain Sciences and the UK Dementia Research Institute, The University of Edinburgh, 1 George Square, Edinburgh, EH8 9JZ Scotland, UK
| | - Tara L. Spires-Jones
- Centre for Discovery Brain Sciences and the UK Dementia Research Institute, The University of Edinburgh, 1 George Square, Edinburgh, EH8 9JZ Scotland, UK
| | - Claire S. Durrant
- Centre for Discovery Brain Sciences and the UK Dementia Research Institute, The University of Edinburgh, 1 George Square, Edinburgh, EH8 9JZ Scotland, UK
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Drosophila Tau Negatively Regulates Translation and Olfactory Long-Term Memory, But Facilitates Footshock Habituation and Cytoskeletal Homeostasis. J Neurosci 2019; 39:8315-8329. [PMID: 31488613 DOI: 10.1523/jneurosci.0391-19.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 07/24/2019] [Accepted: 08/07/2019] [Indexed: 01/07/2023] Open
Abstract
Although the involvement of pathological tau in neurodegenerative dementias is indisputable, its physiological roles have remained elusive in part because its abrogation has been reported without overt phenotypes in mice and Drosophila This was addressed using the recently described Drosophila tauKO and Mi{MIC} mutants and focused on molecular and behavioral analyses. Initially, we show that Drosophila tau (dTau) loss precipitates dynamic cytoskeletal changes in the adult Drosophila CNS and translation upregulation. Significantly, we demonstrate for the first time distinct roles for dTau in adult mushroom body (MB)-dependent neuroplasticity as its downregulation within α'β'neurons impairs habituation. In accord with its negative regulation of translation, dTau loss specifically enhances protein synthesis-dependent long-term memory (PSD-LTM), but not anesthesia-resistant memory. In contrast, elevation of the protein in the MBs yielded premature habituation and depressed PSD-LTM. Therefore, tau loss in Drosophila dynamically alters brain cytoskeletal dynamics and profoundly affects neuronal proteostasis and plasticity.SIGNIFICANCE STATEMENT We demonstrate that despite modest sequence divergence, the Drosophila tau (dTau) is a true vertebrate tau ortholog as it interacts with the neuronal microtubule and actin cytoskeleton. Novel physiological roles for dTau in regulation of translation, long-term memory, and footshock habituation are also revealed. These emerging insights on tau physiological functions are invaluable for understanding the molecular pathways and processes perturbed in tauopathies.
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Andrés-Benito P, Gelpi E, Povedano M, Santpere G, Ferrer I. Gene Expression Profile in Frontal Cortex in Sporadic Frontotemporal Lobar Degeneration-TDP. J Neuropathol Exp Neurol 2019; 77:608-627. [PMID: 29788265 DOI: 10.1093/jnen/nly037] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Molecular alterations compromising key metabolic pathways are poorly understood in sporadic frontotemporal lobar degeneration with TDP-43 pathology (sFTLD-TDP). Whole-transcriptome array, RT-qPCR validation, gel electrophoresis, and Western blotting, and mitochondrial electron transport chain (ETC) activity were comparatively examined in frontal cortex (area 8) of 16 sFTLD-TDP cases and 14 controls. Assessment of 111 genes by RT-qPCR showed deregulation of 81 genes linked to neurotransmission and synapses, neuronal architecture, cytoskeleton of axons and dendrites, vesicle trafficking, purines, mitochondria, and energy metabolism in sFTLD-TDP. Western blotting studies disclosed downregulation of several mitochondrial subunits encoded by genomic DNA and MT-CO1 encoded by the mitochondrial DNA. Mitochondrial ETC activity of complexes I, IV, and V was decreased in sFTLD-TDP. These findings provide robust information about downregulation of genes involved in vital biochemical pathways and in synaptic neurotransmission which may help to increase understanding about the biochemical substrates of clinical manifestations in sFTLD-TDP.
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Affiliation(s)
- Pol Andrés-Benito
- Neuropathology, Pathologic Anatomy Service, Bellvitge University Hospital, IDIBELL, Hospitalet de Llobregat, Spain.,Biomedical Network Research Center on Neurodegenerative Diseases (CIBERNED), Institute Carlos III, Hospitalet de Llobregat, Spain
| | - Ellen Gelpi
- Neurological Tissue Bank of the Biobanc-Hospital Clínic-Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), Barcelona, Spain.,Institute of Neurology, Medical University of Vienna, Vienna, Austria
| | - Mónica Povedano
- Functional Unit of Amyotrophic Lateral Sclerosis (UFELA), Service of Neurology, Bellvitge University Hospital, Hospitalet de Llobregat, Spain
| | - Gabriel Santpere
- Department of Neurobiology, Yale School of Medicine, New Haven, Connecticut.,Department of Experimental and Health Sciences, IBE, Institute of Evolutionary Biology, Universitat Pompeu Fabra-CSIC, Barcelona, Spain
| | - Isidro Ferrer
- Neuropathology, Pathologic Anatomy Service, Bellvitge University Hospital, IDIBELL, Hospitalet de Llobregat, Spain.,Biomedical Network Research Center on Neurodegenerative Diseases (CIBERNED), Institute Carlos III, Hospitalet de Llobregat, Spain.,Department of Pathology and Experimental Therapeutics, University of Barcelona, Hospitalet de Llobregat, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain
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Joel Z, Izquierdo P, Salih DA, Richardson JC, Cummings DM, Edwards FA. Improving Mouse Models for Dementia. Are All the Effects in Tau Mouse Models Due to Overexpression? COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2019; 83:151-161. [PMID: 30745408 DOI: 10.1101/sqb.2018.83.037531] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mouse models of Alzheimer's disease have commonly used transgenic overexpression of genes involved in production of amyloid β (APP and/or PSEN1/2) or Tau (MAPT) with mutations that result in familial forms of dementia. We discuss possible improvements that may create full models while avoiding the problems of overexpression and report synaptic results in APPKI models. We stress use of inappropriate controls without overexpression of the normal human protein and the mismatch between the learning deficits reported in mice with plaques but no tangles and the human condition. We focus on Tau overexpression, including new data that support previous reports of the grossly nonlinear relationship between Tau overexpression and neurofibrillary tangle load, with a twofold increase in Tau protein, resulting in a 100-fold increase in tangle density. These data also support the hypothesis that a high concentration of soluble Tau, in overexpression models, plays an important direct role in neurodegeneration, rather than only via aggregation. Finally, we hypothesize that there is an optimal concentration range over which Tau can bind to microtubules and a threshold beyond which much of the overexpressed protein is unable to bind. The excess thus causes toxicity in ways not necessarily related to the process in human dementias.
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Affiliation(s)
- Zelah Joel
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, United Kingdom
| | - Pablo Izquierdo
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, United Kingdom
| | - Dervis A Salih
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, United Kingdom
| | - Jill C Richardson
- Neurosciences Therapeutic Area, GlaxoSmithKline R&D, Stevenage, SG1 2NY, United Kingdom
| | - Damian M Cummings
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, United Kingdom
| | - Frances A Edwards
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, United Kingdom
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Gonçalves RA, Wijesekara N, Fraser PE, De Felice FG. The Link Between Tau and Insulin Signaling: Implications for Alzheimer's Disease and Other Tauopathies. Front Cell Neurosci 2019; 13:17. [PMID: 30804755 PMCID: PMC6371747 DOI: 10.3389/fncel.2019.00017] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 01/16/2019] [Indexed: 01/27/2023] Open
Abstract
The microtubule-associated protein tau (MAPT) is mainly identified as a tubulin binding protein essential for microtubule dynamics and assembly and for neurite outgrowth. However, several other possible functions for Tau remains to be investigated. Insulin signaling is important for synaptic plasticity and memory formation and therefore is essential for proper brain function. Tau has recently been characterized as an important regulator of insulin signaling, with evidence linking Tau to brain and peripheral insulin resistance and beta cell dysfunction. In line with this notion, the hypothesis of Tau pathology as a key trigger of impaired insulin sensitivity and secretion has emerged. Conversely, insulin resistance can also favor Tau dysfunction, resulting in a vicious cycle of these events. In this review article, we discuss recent evidence linking Tau pathology, insulin resistance and insulin deficiency. We further highlight the deleterious consequences of Tau pathology-induced insulin resistance to the brain and/or peripheral tissues, suggesting that these are key events mediating cognitive decline in Alzheimer’s disease (AD) and other tauopathies.
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Affiliation(s)
- Rafaella Araujo Gonçalves
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada.,Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - Nadeeja Wijesekara
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - Paul E Fraser
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Fernanda G De Felice
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada.,Department of Psychiatry, Queen's University, Kingston, ON, Canada.,Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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9
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Lane DJ, Ayton S, Bush AI. Iron and Alzheimer’s Disease: An Update on Emerging Mechanisms. J Alzheimers Dis 2018; 64:S379-S395. [DOI: 10.3233/jad-179944] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Darius J.R. Lane
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Scott Ayton
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Ashley I. Bush
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience & Mental Health, The University of Melbourne, Parkville, VIC, Australia
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Abstract
PURPOSE OF REVIEW The purpose of this review is to provide an update on the role of tau beyond the stabilization of microtubules and on the clinical, pathological, diagnostic and therapeutic aspects of tauopathies. RECENT FINDINGS Beyond its function as a microtubule-associated tau protein, tau is also involved in gene regulation, signal transduction and metabolism. Experimental models allow for the development of new diagnostic and therapeutic tools. Tauopathies encompass different disorders that may manifest with various clinical syndromes. Differential diagnosis with other proteinopathies is still challenging. Cerebrospinal fluid biomarkers and radiotracers were extensively studied in the last year. Although diagnostic accuracy remains deceiving in non-Alzheimer's disease tauopathies, positron emission tomography tau tracers could be used to monitor disease progression. SUMMARY Despite the advent of novel therapeutic approaches and the increasing number of clinical trials in tauopathies, accurate clinical diagnosis is still an unmet need and better tau biomarkers are still desperately needed. Although primary taupathies are rare and heterogeneous disorders, their combined prevalence and the importance of tau disorder in Alzheimer's disease and secondary tauopathies makes research on tauopathy a priority - because it could benefit many patients.
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Tang X, Jiao L, Zheng M, Yan Y, Nie Q, Wu T, Wan X, Zhang G, Li Y, Wu S, Jiang B, Cai H, Xu P, Duan J, Lin X. Tau Deficiency Down-Regulated Transcription Factor Orthodenticle Homeobox 2 Expression in the Dopaminergic Neurons in Ventral Tegmental Area and Caused No Obvious Motor Deficits in Mice. Neuroscience 2018; 373:52-59. [PMID: 29337233 PMCID: PMC5819331 DOI: 10.1016/j.neuroscience.2018.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/22/2017] [Accepted: 01/03/2018] [Indexed: 12/24/2022]
Abstract
Tau protein participates in microtubule stabilization, axonal transport, and protein trafficking. Loss of normal tau function will exert a negative effect. However, current knowledge on the impact of tau deficiency on the motor behavior and related neurobiological changes is controversial. In this study, we examined motor functions and analyzed several proteins implicated in the maintenance of midbrain dopaminergic (DA) neurons (mDANs) function of adult and aged tau+/+, tau+/-, tau-/- mice. We found tau deficiency could not induce significant motor disorders. However, we discovered lower expression levels of transcription factors Orthodenticle homeobox 2 (OTX2) of mDANs in older aged mice. Compared with age-matched tau+/+ mice, there were 54.1% lower (p = 0.0192) OTX2 protein (OTX2-fluorescence intensity) in VTA DA neurons of tau+/- mice and 43.6% lower (p = 0.0249) OTX2 protein in VTA DA neurons of tau-/- mice at 18 months old. Combined with the relevant reports, our results suggested that tau deficiency alone might not be enough to mimic the pathology of Parkinson's disease. However, OTX2 down-regulation indicates that mDANs of tau-deficient mice will be more sensitive to toxic damage from MPTP.
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Affiliation(s)
- Xiaolu Tang
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Luyan Jiao
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Meige Zheng
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Yan Yan
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Qi Nie
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Ting Wu
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Xiaomei Wan
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Guofeng Zhang
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Yonglin Li
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Song Wu
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Bin Jiang
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Huaibin Cai
- Transgenics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Pingyi Xu
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangdong 510120, China.
| | - Jinhai Duan
- Department of Neurology & Guangdong Institute of Geriatrics, Guangdong General Hospital, #106, Zhongshan 2nd Road, Guanzhou 510080, China.
| | - Xian Lin
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China; Department of Anatomy & Research Center for Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China.
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Lei P, Ayton S, Appukuttan AT, Moon S, Duce JA, Volitakis I, Cherny R, Wood SJ, Greenough M, Berger G, Pantelis C, McGorry P, Yung A, Finkelstein DI, Bush AI. Lithium suppression of tau induces brain iron accumulation and neurodegeneration. Mol Psychiatry 2017; 22:396-406. [PMID: 27400857 DOI: 10.1038/mp.2016.96] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/25/2016] [Accepted: 05/09/2016] [Indexed: 02/05/2023]
Abstract
Lithium is a first-line therapy for bipolar affective disorder. However, various adverse effects, including a Parkinson-like hand tremor, often limit its use. The understanding of the neurobiological basis of these side effects is still very limited. Nigral iron elevation is also a feature of Parkinsonian degeneration that may be related to soluble tau reduction. We found that magnetic resonance imaging T2 relaxation time changes in subjects commenced on lithium therapy were consistent with iron elevation. In mice, lithium treatment lowers brain tau levels and increases nigral and cortical iron elevation that is closely associated with neurodegeneration, cognitive loss and parkinsonian features. In neuronal cultures lithium attenuates iron efflux by lowering tau protein that traffics amyloid precursor protein to facilitate iron efflux. Thus, tau- and amyloid protein precursor-knockout mice were protected against lithium-induced iron elevation and neurotoxicity. These findings challenge the appropriateness of lithium as a potential treatment for disorders where brain iron is elevated (for example, Alzheimer's disease), and may explain lithium-associated motor symptoms in susceptible patients.
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Affiliation(s)
- P Lei
- Department of Neurology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Sichuan, China.,Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - S Ayton
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - A T Appukuttan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - S Moon
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - J A Duce
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia.,Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, West Yorkshire, UK
| | - I Volitakis
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - R Cherny
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - S J Wood
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Parkville, VIC, Australia.,School of Psychology, University of Birmingham, Birmingham, UK
| | - M Greenough
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - G Berger
- ORYGEN Research Centre, University of Melbourne and Melbourne Health, Parkville, VIC, Australia.,Department of Child and Adolescent Psychiatry, University of Zürich, Zurich, Switzerland
| | - C Pantelis
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia.,Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Parkville, VIC, Australia.,Centre for Neural Engineering, Department of Electrical and Electronic Engineering, University of Melbourne, Parkville, VIC, Australia
| | - P McGorry
- ORYGEN Research Centre, University of Melbourne and Melbourne Health, Parkville, VIC, Australia
| | - A Yung
- Institute of Brain, Behaviour and Mental Health, University of Manchester and Greater Manchester West NHS Mental Health Trust, Manchester, UK
| | - D I Finkelstein
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - A I Bush
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
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13
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Papegaey A, Eddarkaoui S, Deramecourt V, Fernandez-Gomez FJ, Pantano P, Obriot H, Machala C, Anquetil V, Camuzat A, Brice A, Maurage CA, Le Ber I, Duyckaerts C, Buée L, Sergeant N, Buée-Scherrer V. Reduced Tau protein expression is associated with frontotemporal degeneration with progranulin mutation. Acta Neuropathol Commun 2016; 4:74. [PMID: 27435172 PMCID: PMC4952067 DOI: 10.1186/s40478-016-0345-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 07/10/2016] [Indexed: 12/12/2022] Open
Abstract
Reduction of Tau protein expression was described in 2003 by Zhukareva et al. in a variant of frontotemporal lobar degeneration (FTLD) referred to as diagnosis of dementia lacking distinctive histopathology, then re-classified as FTLD with ubiquitin inclusions. However, the analysis of Tau expression in FTLD has not been reconsidered since then. Knowledge of the molecular basis of protein aggregates and genes that are mutated in the FTLD spectrum would enable to determine whether the “Tau-less” is a separate pathological entity or if it belongs to an existing subclass of FTLD. To address this question, we have analyzed Tau expression in the frontal brain areas from control, Alzheimer’s disease and FTLD cases, including FTLD- Tau (MAPT), FTLD-TDP (sporadic, FTLD-TDP-GRN, FTLD-TDP-C9ORF72) and sporadic FTLD-FUS, using western blot and 2D-DIGE (Two-Dimensional fluorescence Difference Gel Electrophoresis) approaches. Surprisingly, we found that most of the FTLD-TDP-GRN brains are characterized by a huge reduction of Tau protein expression without any decrease in Tau mRNA levels. Interestingly, only cases affected by point mutations, rather than cases with total deletion of one GRN allele, seem to be affected by this reduction of Tau protein expression. Moreover, proteomic analysis highlighted correlations between reduced Tau protein level, synaptic impairment and massive reactive astrogliosis in these FTLD-GRN cases. Consistent with a recent study, our data also bring new insights regarding the role of progranulin in neurodegeneration by suggesting its involvement in lysosome and synaptic regulation. Together, our results demonstrate a strong association between progranulin deficiency and reduction of Tau protein expression that could lead to severe neuronal and glial dysfunctions. Our study also indicates that this FTLD-TDP-GRN subgroup could be part as a distinct entity of FTLD classification.
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Lopes S, Lopes A, Pinto V, Guimarães MR, Sardinha VM, Duarte‐Silva S, Pinheiro S, Pizarro J, Oliveira JF, Sousa N, Leite‐Almeida H, Sotiropoulos I. Absence of Tau triggers age-dependent sciatic nerve morphofunctional deficits and motor impairment. Aging Cell 2016; 15:208-16. [PMID: 26748966 PMCID: PMC4783352 DOI: 10.1111/acel.12391] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2015] [Indexed: 11/29/2022] Open
Abstract
Dementia is the cardinal feature of Alzheimer's disease (AD), yet the clinical symptoms of this disorder also include a marked loss of motor function. Tau abnormal hyperphosphorylation and malfunction are well‐established key events in AD neuropathology but the impact of the loss of normal Tau function in neuronal degeneration and subsequent behavioral deficits is still debated. While Tau reduction has been increasingly suggested as therapeutic strategy against neurodegeneration, particularly in AD, there is controversial evidence about whether loss of Tau progressively impacts on motor function arguing about damage of CNS motor components. Using a variety of motor‐related tests, we herein provide evidence of an age‐dependent motor impairment in Tau−/− animals that is accompanied by ultrastructural and functional impairments of the efferent fibers that convey motor‐related information. Specifically, we show that the sciatic nerve of old (17–22‐months) Tau−/− mice displays increased degenerating myelinated fibers and diminished conduction properties, as compared to age‐matched wild‐type (Tau+/+) littermates and younger (4–6 months) Tau−/− and Tau+/+ mice. In addition, the sciatic nerves of Tau−/− mice exhibit a progressive hypomyelination (assessed by g‐ratio) specifically affecting large‐diameter, motor‐related axons in old animals. These findings suggest that loss of Tau protein may progressively impact on peripheral motor system.
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Affiliation(s)
- Sofia Lopes
- Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Campus Gualtar 4710‐057 Braga Portugal
- ICVS/3B's – PT Government Associate Laboratory Braga/Guimarães Portugal
| | - André Lopes
- Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Campus Gualtar 4710‐057 Braga Portugal
- ICVS/3B's – PT Government Associate Laboratory Braga/Guimarães Portugal
| | - Vítor Pinto
- Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Campus Gualtar 4710‐057 Braga Portugal
- ICVS/3B's – PT Government Associate Laboratory Braga/Guimarães Portugal
| | - Marco R. Guimarães
- Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Campus Gualtar 4710‐057 Braga Portugal
- ICVS/3B's – PT Government Associate Laboratory Braga/Guimarães Portugal
| | - Vanessa Morais Sardinha
- Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Campus Gualtar 4710‐057 Braga Portugal
- ICVS/3B's – PT Government Associate Laboratory Braga/Guimarães Portugal
| | - Sara Duarte‐Silva
- Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Campus Gualtar 4710‐057 Braga Portugal
- ICVS/3B's – PT Government Associate Laboratory Braga/Guimarães Portugal
| | - Sara Pinheiro
- Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Campus Gualtar 4710‐057 Braga Portugal
- ICVS/3B's – PT Government Associate Laboratory Braga/Guimarães Portugal
| | - João Pizarro
- Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Campus Gualtar 4710‐057 Braga Portugal
- ICVS/3B's – PT Government Associate Laboratory Braga/Guimarães Portugal
| | - João Filipe Oliveira
- Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Campus Gualtar 4710‐057 Braga Portugal
- ICVS/3B's – PT Government Associate Laboratory Braga/Guimarães Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Campus Gualtar 4710‐057 Braga Portugal
- ICVS/3B's – PT Government Associate Laboratory Braga/Guimarães Portugal
| | - Hugo Leite‐Almeida
- Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Campus Gualtar 4710‐057 Braga Portugal
- ICVS/3B's – PT Government Associate Laboratory Braga/Guimarães Portugal
| | - Ioannis Sotiropoulos
- Life and Health Sciences Research Institute (ICVS) School of Health Sciences University of Minho Campus Gualtar 4710‐057 Braga Portugal
- ICVS/3B's – PT Government Associate Laboratory Braga/Guimarães Portugal
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Sancesario GM, Bernardini S. How many biomarkers to discriminate neurodegenerative dementia? Crit Rev Clin Lab Sci 2015; 52:314-26. [PMID: 26292074 DOI: 10.3109/10408363.2015.1051658] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A number of cerebrospinal fluid (CSF) biomarkers are currently used for the diagnosis of dementia. Opposite changes in the level of amyloid-β(1-42) versus total tau and phosphorylated-tau181 in the CSF reflect the specific pathology of Alzheimer's disease (AD) in the brain. This panel of biomarkers has proven to be effective to differentiate AD from controls and from the major types of neurodegenerative dementia, and to evaluate the progression from mild cognitive impairment to AD. In the absence of specific biomarkers reflecting the pathologies of the other most common forms of dementia, such as Lewy Body disease, Frontotemporal lobar degeneration, Creutzfeldt-Jakob disease, etc., the evaluation of biomarkers of AD pathology is used, attempting to exclude rather than to confirm AD. Other biomarkers included in the common clinical practice do not clearly relate to the underlying pathology: progranulin (PGRN) is a selective marker of frontotemporal dementia with mutations in the PGRN gene; the 14-3-3 protein is a highly sensitive and specific marker for Creutzfeldt-Jakob disease, but has to be used carefully in differentiating rapid progressive dementia; and α-synuclein is an emerging candidate biomarker of the different forms of synucleinopathy. This review summarizes several biomarkers of neurodegenerative dementia validated based on the neuropathological processes occurring in brain tissue. Notwithstanding the paucity of pathologically validated biomarkers and their high analytical variability, the combinations of these biomarkers may well represent a key and more precise analytical and diagnostic tool in the complex plethora of degenerative dementia.
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Affiliation(s)
- Giulia M Sancesario
- a Department of Clinical and Behavioural Neurology , Santa Lucia Foundation, IRCCS , Rome , Italy and
| | - Sergio Bernardini
- b Department of Experimental Medicine and Surgery , Tor Vergata University of Rome , Rome , Italy
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16
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Aberrant Wnt signaling pathway in medial temporal lobe structures of Alzheimer’s disease. J Neural Transm (Vienna) 2015; 122:1303-18. [PMID: 25680440 DOI: 10.1007/s00702-015-1375-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 02/03/2015] [Indexed: 01/13/2023]
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Abstract
No disease modifying therapy exists for Alzheimer's disease (AD). The growing burden of this disease to our society necessitates continued investment in drug development. Over the last decade, multiple phase 3 clinical trials testing drugs that were designed to target established disease mechanisms of AD have all failed to benefit patients. There is, therefore, a need for new treatment strategies. Changes to the transition metals, zinc, copper, and iron, in AD impact on the molecular mechanisms of disease, and targeting these metals might be an alternative approach to treat the disease. Here we review how metals feature in molecular mechanisms of AD, and we describe preclinical and clinical data that demonstrate the potential for metal-based drug therapy.
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Affiliation(s)
- Scott Ayton
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052 VIC Australia
| | - Peng Lei
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052 VIC Australia
| | - Ashley I. Bush
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, 3052 VIC Australia
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18
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Lei P, Ayton S, Moon S, Zhang Q, Volitakis I, Finkelstein DI, Bush AI. Motor and cognitive deficits in aged tau knockout mice in two background strains. Mol Neurodegener 2014; 9:29. [PMID: 25124182 PMCID: PMC4141346 DOI: 10.1186/1750-1326-9-29] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 08/10/2014] [Indexed: 11/13/2022] Open
Abstract
Background We recently reported that Parkinsonian and dementia phenotypes emerge between 7-12 months of age in tau-/- mice on a Bl6/129sv mixed background. These observations were partially replicated by another group using pure Bl6 background tau-/- mice, but notably they did not observe a cognitive phenotype. A third group using Bl6 background tau-/- mice found cognitive impairment at 20-months of age. Results To reconcile the observations, here we considered the genetic, dietary and environmental variables in both studies, and performed an extended set of behavioral studies on 12-month old tau+/+, tau+/-, and tau-/- mice comparing Bl6/129sv to Bl6 backgrounds. We found that tau-/- in both backgrounds exhibited reduced tyrosine hydroxylase-positive nigral neuron and impaired motor function in all assays used, which was ameliorated by oral treatment with L-DOPA, and not confounded by changes in body weight. Tau-/- in the C57BL6/SV129 background exhibited deficits in the Y-maze cognition task, but the mice on the Bl6 background did not. Conclusions These results validate our previous report on the neurodegenerative phenotypes of aged tau-/- mice, and show that genetic background may impact the extent of cognitive impairment in these mice. Therefore excessive lowering of tau should be avoided in therapeutic strategies for AD.
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Affiliation(s)
| | | | | | | | | | | | - Ashley I Bush
- Oxidation Biology Unit, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, Victoria, Australia.
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19
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Ayton S, Lei P, Bush AI. Metallostasis in Alzheimer's disease. Free Radic Biol Med 2013; 62:76-89. [PMID: 23142767 DOI: 10.1016/j.freeradbiomed.2012.10.558] [Citation(s) in RCA: 247] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 10/30/2012] [Accepted: 10/30/2012] [Indexed: 12/22/2022]
Abstract
2012 has been another year in which multiple large-scale clinical trials for Alzheimer's disease (AD) have failed to meet their clinical endpoints. With the social and financial burden of this disease increasing every year, the onus is now on the field of AD researchers to investigate alternative ideas to deliver outcomes for patients. Although several major clinical trials targeting Aβ have failed, three smaller clinical trials targeting metal interactions with Aβ have all shown benefit for patients. Here we review the genetic, pathological, biochemical, and pharmacological evidence that underlies the metal hypothesis of AD. The AD-affected brain suffers from metallostasis, or fatigue of metal trafficking, resulting in redistribution of metals into inappropriate compartments. The metal hypothesis is built upon a triad of transition elements: iron, copper, and zinc. The hypothesis has matured from early investigations showing amyloidogenic and oxidative stress consequences of these metals; recently, disease-related proteins, APP, tau, and presenilin, have been shown to have major roles in metal regulation, which provides insight into the pathway of neurodegeneration in AD and illuminates potential new therapeutic avenues.
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Affiliation(s)
- Scott Ayton
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Peng Lei
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Ashley I Bush
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC 3010, Australia.
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Hare D, Ayton S, Bush A, Lei P. A delicate balance: Iron metabolism and diseases of the brain. Front Aging Neurosci 2013; 5:34. [PMID: 23874300 PMCID: PMC3715022 DOI: 10.3389/fnagi.2013.00034] [Citation(s) in RCA: 275] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/25/2013] [Indexed: 12/12/2022] Open
Abstract
Iron is the most abundant transition metal within the brain, and is vital for a number of cellular processes including neurotransmitter synthesis, myelination of neurons, and mitochondrial function. Redox cycling between ferrous and ferric iron is utilized in biology for various electron transfer reactions essential to life, yet this same chemistry mediates deleterious reactions with oxygen that induce oxidative stress. Consequently, there is a precise and tightly controlled mechanism to regulate iron in the brain. When iron is dysregulated, both conditions of iron overload and iron deficiencies are harmful to the brain. This review focuses on how iron metabolism is maintained in the brain, and how an alteration to iron and iron metabolism adversely affects neurological function.
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Affiliation(s)
- Dominic Hare
- The Florey Institute of Neuroscience and Mental Health, University of MelbourneVIC, Australia
- Elemental Bio-imaging Facility, University of TechnologySydney, NSW, Australia
| | - Scott Ayton
- The Florey Institute of Neuroscience and Mental Health, University of MelbourneVIC, Australia
| | - Ashley Bush
- The Florey Institute of Neuroscience and Mental Health, University of MelbourneVIC, Australia
| | - Peng Lei
- The Florey Institute of Neuroscience and Mental Health, University of MelbourneVIC, Australia
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Irwin DJ, Trojanowski JQ, Grossman M. Cerebrospinal fluid biomarkers for differentiation of frontotemporal lobar degeneration from Alzheimer's disease. Front Aging Neurosci 2013; 5:6. [PMID: 23440936 PMCID: PMC3578350 DOI: 10.3389/fnagi.2013.00006] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Accepted: 02/05/2013] [Indexed: 12/12/2022] Open
Abstract
Accurate ante mortem diagnosis in frontotemporal lobar degeneration (FTLD) is crucial to the development and implementation of etiology-based therapies. Several neurodegenerative disease-associated proteins, including the major protein constituents of inclusions in Alzheimer's disease (AD) associated with amyloid-beta (Aβ(1-42)) plaque and tau neurofibrillary tangle pathology, can be measured in cerebrospinal fluid (CSF) for diagnostic applications. Comparative studies using autopsy-confirmed samples suggest that CSF total-tau (t-tau) and Aβ(1-42) levels can accurately distinguish FTLD from AD, with a high t-tau to Aβ(1-42) ratio diagnostic of AD; however, there is also an urgent need for FTLD-specific biomarkers. These analytes will require validation in large autopsy-confirmed cohorts and face challenges of standardization of within- and between-laboratory sources of error. In addition, CSF biomarkers with prognostic utility and longitudinal study of CSF biomarker levels over the course of disease are also needed. Current goals in the field include identification of analytes that are easily and reliably measured and can be used alone or in a multi-modal approach to provide an accurate prediction of underlying neuropathology for use in clinical trials of disease modifying treatments in FTLD. To achieve these goals it will be of the utmost importance to view neurodegenerative disease, including FTLD, as a clinicopathological entity, rather than exclusively a clinical syndrome.
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Affiliation(s)
- David J Irwin
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Alzheimer's Disease Core Center, Institute on Aging, University of Pennsylvania Philadelphia, PA, USA ; Department of Neurology, Center for Frontotemporal Dementia, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
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23
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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: 440] [Impact Index Per Article: 36.7] [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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Abstract
AbstractAlzheimer’s disease (AD) and frontotemporal lobar degeneration (FTLD) represent an important differential diagnostic problem in clinical practice. The identification for new biomarkers that would help establishing the diagnosis and primary cause of the dementia is therefore highly relevant. The aim of this study was to investigate the diagnostic accuracy of three potential CSF biomarkers, total tau protein (t-tau), tau protein phosphorylated at threonine 181 (p-tau181), and tau protein phosphorylated at serine 199 (p-tau199) in the differential diagnosis of AD and FTLD patients in relatively young age groups. The concentrations of the three CSF biomarkers were measured in 25 FTLD patients, 27 AD patients, and 25 non-demented (ND) subjects. The CSF concentrations of all three markers were significantly higher in AD than in FTLD cases (p < 0.001) or ND controls (p < 0.001). No difference was observed in FTLD compared to the ND group, except for p-tau181 (p = 0.028). When sensitivity was set at 85% or higher, specificity in differentiation between FTLD and AD patients reached 40% for t-tau, 37.5% for p-tau181 and 56% for p-tau199. Improvement of the diagnostic accuracy upon logistic regression analysis with t-tau and p-tau199 as independent variables showed that 22 out of 25 FTLD patients could be correctly classified. In conclusion, none of the markers per se fulfilled the criteria for the „ideal“ marker (sensitivity and specificity higher than 85%). However, combination of t-tau and p-tau199 classified correctly 88% of FTLD patients, thus largely satisfying practical requirements.
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van Eersel J, Bi M, Ke YD, Hodges JR, Xuereb JH, Gregory GC, Halliday GM, Götz J, Kril JJ, Ittner LM. Phosphorylation of soluble tau differs in Pick's disease and Alzheimer's disease brains. J Neural Transm (Vienna) 2009; 116:1243-51. [PMID: 19693433 DOI: 10.1007/s00702-009-0293-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 08/03/2009] [Indexed: 11/28/2022]
Abstract
Frontotemporal lobar degeneration (FTLD) is a common cause of presenile dementia characterised by behavioural and language disturbances. Pick's disease (PiD) is a subtype of FTLD, which presents with intraneuronal inclusions consisting of hyperphosphorylated tau protein aggregates. Although Alzheimer's disease (AD) is also characterised by tau lesions, these are both histologically and biochemically distinct from the tau aggregates found in PiD. What determines the distinct characteristics of these tau lesions is unknown. As phosphorylated, soluble tau has been suggested to be the precursor of tau aggregates, we compared both the level and phosphorylation profile of tau in tissue extracts of AD and PiD brains to determine whether the differences in the tau lesions are reflected by differences in soluble tau. Levels of soluble tau were decreased in AD but not PiD. In addition, soluble tau was phosphorylated to a greater extent in AD than in PiD and displayed a different phosphorylation profile in the two disorders. Consistently, tau kinases were activated to different degrees in AD compared with PiD. Such differences in solubility and phosphorylation may contribute, at least in part, to the formation of distinct tau deposits, but may also have implications for the clinical differences between AD and PiD.
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Affiliation(s)
- Janet van Eersel
- Discipline of Pathology, The University of Sydney, Sydney, NSW, 2006, Australia
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Sergeant N, Bretteville A, Hamdane M, Caillet-Boudin ML, Grognet P, Bombois S, Blum D, Delacourte A, Pasquier F, Vanmechelen E, Schraen-Maschke S, Buée L. Biochemistry of Tau in Alzheimer's disease and related neurological disorders. Expert Rev Proteomics 2008; 5:207-24. [PMID: 18466052 DOI: 10.1586/14789450.5.2.207] [Citation(s) in RCA: 215] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Microtubule-associated Tau proteins belong to a family of factors that polymerize tubulin dimers and stabilize microtubules. Tau is strongly expressed in neurons, localized in the axon and is essential for neuronal plasticity and network. From the very beginning of Tau discovery, proteomics methods have been essential to the knowledge of Tau biochemistry and biology. In this review, we have summarized the main contributions of several proteomic methods in the understanding of Tau, including expression, post-translational modifications and structure, in both physiological and pathophysiological aspects. Finally, recent advances in proteomics technology are essential to develop further therapeutic targets and early predictive and discriminative diagnostic assays for Alzheimer's disease and related disorders.
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Sutherland GT, Nowak G, Halliday GM, Kril JJ. Tau isoform expression in frontotemporal dementia without tau deposition. J Clin Neurosci 2007; 14:1182-5. [DOI: 10.1016/j.jocn.2006.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 10/13/2006] [Accepted: 10/18/2006] [Indexed: 11/27/2022]
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Alberici A, Armani M, Paterlini A, Benussi L, Nicosia F, Ghidoni R, Signorini S, Cotelli M, Frisoni GB, Geroldi C, Trevisan CP, Growdon JH, Borroni B, Padovani A, Rossini PM, Binetti G. Tau missing from CSF. J Neurol 2007; 254:107-9. [PMID: 17277912 DOI: 10.1007/s00415-006-0282-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Accepted: 04/27/2006] [Indexed: 11/27/2022]
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Ginsberg SD, Che S, Counts SE, Mufson EJ. Shift in the ratio of three-repeat tau and four-repeat tau mRNAs in individual cholinergic basal forebrain neurons in mild cognitive impairment and Alzheimer's disease. J Neurochem 2006; 96:1401-8. [PMID: 16478530 DOI: 10.1111/j.1471-4159.2005.03641.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Molecular mechanisms underlying tauopathy remain undetermined. In the current study, single cell gene expression profiling was coupled with custom-designed cDNA array analysis to evaluate tau expression and other cytoskeletal elements within individual neuronal populations in patients with no cognitive impairment (NCI), mild cognitive impairment (MCI), and Alzheimer's disease (AD). Results revealed a shift in the ratio of three-repeat tau (3Rtau) to four-repeat tau (4Rtau) mRNAs within individual human cholinergic basal forebrain (CBF) neurons within nucleus basalis (NB) and CA1 hippocampal neurons during the progression of AD, but not during normal aging. A shift in 3Rtau to 4Rtau may precipitate a cascade of events in the selective vulnerability of neurons, ultimately leading to frank neurofibrillary tangle (NFT) formation in tauopathies including AD.
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Affiliation(s)
- Stephen D Ginsberg
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York 10962, USA.
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30
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Mackenzie IR, Baker M, West G, Woulfe J, Qadi N, Gass J, Cannon A, Adamson J, Feldman H, Lindholm C, Melquist S, Pettman R, Sadovnick AD, Dwosh E, Whiteheart SW, Hutton M, Pickering-Brown SM. A family with tau-negative frontotemporal dementia and neuronal intranuclear inclusions linked to chromosome 17. ACTA ACUST UNITED AC 2006; 129:853-67. [PMID: 16401619 DOI: 10.1093/brain/awh724] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Over 30 different mutations have now been identified in MAPt that cause frontotemporal dementia (FTD). However, there are several families with FTD that show definite linkage to the region on chromosome 17 that contains MAPt, in which no mutation(s) has been identified. Although these families could have a complex mutation of the MAPt locus that has evaded detection it is also possible that another gene in this region is associated with FTD. This possibility is supported by neuropathological findings in these families, which consist of neuronal inclusions that are immunoreactive for ubiquitin (ub-ir) but not for tau. In addition to neuronal cytoplasmic inclusions, several chromosome 17-linked families are reported to have ub-ir neuronal intranuclear inclusions (NII); a finding which is uncommon in sporadic FTD. Here, we describe detailed clinical and neuropathological findings in a new large, multigenerational family with autosomal dominant FTD and autopsy proven tau-negative, ub-ir neuronal cytoplasmic and intranuclear inclusions. We have demonstrated that this family is linked to a 19.06 cM region of chromosome 17q21 with a maximum multipoint LOD score of 3.911 containing MAPt. By combining the results of our genetic analysis with those previously published for other families with similar pathology, we have further refined the minimal region to a 3.53 cM region of chromosome 17q21. We did not identify point mutations in MAPt by direct sequencing or any gross MAPt gene alterations using fluorescent in situ hybridization. In addition, tau protein extracted from members of this family was unremarkable in size and quantity as assessed by western blotting. Neuropathological characterization of the ub-ir NII in this family shows that they are positive for promyelocytic leukaemia protein (PML) and SUMO-1 that suggests that these inclusions form in the nuclear body and suggests a possible mechanism of neurodegeneration in tau-negative FTD linked to chromosome 17q21.
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Affiliation(s)
- Ian R Mackenzie
- Department of Pathology, University of British Columbia, Vancouver, Canada
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31
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Abstract
Developments in molecular neuropathology have led to protein-based classification systems for neurodegenerative disorders. Key proteins include alpha-synuclein, amyloid and tau. Alternative mRNA splicing and post-translational change, induced by a bewildering variety of protein modifying processes such as phosphorylation and ubiquitination, have generated insights into new mechanisms of selective neuronal degeneration. The task now is to bring these developments in protein chemistry to the clinic, to try to determine whether this biochemical diversity can help in explaining the phenotypic variability that is so typical of neurodegeneration in general. In this review, we will explore the clinicopathological diversity of the tau-related disorders with specific reference to three of the most common tauopathies, frontotemporal dementia (familial and sporadic), progressive supranuclear palsy and corticobasal degeneration.
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Affiliation(s)
- B Murray
- Department of Neurology, Mater Misericordiae University Hospital, Eccles Street, Dublin 7, Ireland.
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Dermaut B, Kumar-Singh S, Rademakers R, Theuns J, Cruts M, Van Broeckhoven C. Tau is central in the genetic Alzheimer–frontotemporal dementia spectrum. Trends Genet 2005; 21:664-72. [PMID: 16221505 DOI: 10.1016/j.tig.2005.09.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Revised: 08/11/2005] [Accepted: 09/27/2005] [Indexed: 11/28/2022]
Abstract
In contrast to the common and genetically complex senile form of Alzheimer's disease (AD), the molecular genetic dissection of inherited presenile dementias has given important mechanistic insights into the pathogenesis of degenerative brain disease. Here, we focus on recent genotype-phenotype correlative studies in presenile AD and the frontotemporal dementia (FTD) complex of disorders. Together, these studies suggest that AD and FTD are linked in a genetic spectrum of presenile degenerative brain disorders in which tau appears to be the central player.
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Affiliation(s)
- Bart Dermaut
- Department of Molecular Genetics (VIB 8), Flanders Interuniversity Institute for Biotechnology, Neurodegenerative Brain Diseases Group, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, B-2610 Antwerpen, Belgium
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33
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Grossman M, Farmer J, Leight S, Work M, Moore P, Van Deerlin V, Pratico D, Clark CM, Coslett HB, Chatterjee A, Gee J, Trojanowski JQ, Lee VMY. Cerebrospinal fluid profile in frontotemporal dementia and Alzheimer's disease. Ann Neurol 2005; 57:721-9. [PMID: 15852395 DOI: 10.1002/ana.20477] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We assessed cerebrospinal fluid (CSF) levels of tau and other biomarkers of neurodegenerative disease. CSF tau levels vary widely in reports of frontotemporal dementia (FTD). CSF samples were assayed for tau, amyloid beta1-42 (A1-42), and the isoprostane 8,12-iso-iPF2a-VI (iP) prospectively in 64 patients with FTD, retrospectively in 26 autopsied cases with FTD or Alzheimer's disease (AD), and in 13 healthy seniors. To validate our observations in vivo, we correlated CSF tau levels with cortical atrophy in 17 FTD patients using voxel-based morphometry analyses of high-resolution magnetic resonance imaging. CSF levels of tau, Abeta1-42, and iP differed significantly in FTD compared with AD. Individual patient analyses showed that 34% of FD patients had significantly low levels of CSF tau, although this was never seen in AD. A discriminant analysis based on CSF levels of tau, Abeta1-42, and iP was able to classify 88.5% of these patients in a manner that corresponds to their clinical or autopsy diagnosis. Magnetic resonance imaging studies showed that CSF tau levels correlate significantly with right frontal and left temporal cortical atrophy, brain regions known to be atrophic in patients with autopsy-proved FTD. We conclude that CSF tau levels are significantly reduced in many patients with FTD.
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Affiliation(s)
- Murray Grossman
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-4283, USA.
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Mott RT, Dickson DW, Trojanowski JQ, Zhukareva V, Lee VM, Forman M, Van Deerlin V, Ervin JF, Wang DS, Schmechel DE, Hulette CM. Neuropathologic, biochemical, and molecular characterization of the frontotemporal dementias. J Neuropathol Exp Neurol 2005; 64:420-8. [PMID: 15892300 DOI: 10.1093/jnen/64.5.420] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The frontotemporal dementias (FTDs) are a heterogeneous group of neurodegenerative disorders that are characterized clinically by dementia, personality changes, language impairment, and occasionally extrapyramidal movement disorders. Historically, the diagnosis and classification of FTDs has been fraught with difficulties, especially with regard to establishing a consensus on the neuropathologic diagnosis. Recently, an international group of scientists participated in a consensus conference to develop such neuropathologic criteria. They recommended a diagnostic classification scheme that incorporated a biochemical analysis of the insoluble tau isoform composition, as well as ubiquitin immunohistochemistry. The use and reliability of this classification system has yet to be examined. In this study, we evaluated 21 cases of FTD. Using traditional histochemical stains and tau protein and ubiquitin immunohistochemistry, we separated each case into one of the following categories: classic Pick disease (PiD; n = 7), corticobasal degeneration (CBD; n = 5), dementia lacking distinctive histopathologic features (DLDH; n = 4), progressive supranuclear palsy (PSP; n = 2), frontotemporal lobar degeneration with motor neuron disease or motor neuron disease-type inclusions (FTLD-MND/MNI; n = 2), and neurofibrillary tangle dementia (NFTD; n = 1). Additionally, we independently categorized each case by the insoluble tau isoform pattern, including 3R (n = 5), 4R (n = 7), 3R/4R (n = 3), and no insoluble tau (n = 6). As suggested by the proposed diagnostic scheme, we found that the insoluble tau isoform patterns correlated strongly with the independently derived histopathologic diagnoses (p < 0.001). The data show that cases containing predominantly 3R tau were classic PiD (100%). Cases with predominantly 4R tau were either CBD (71%) or PSP (29%). Cases with both 3R and 4R tau were either a combination of PiD and Alzheimer disease (67%) or NFTD (33%). Finally, cases with no insoluble tau were either DLDH (67%) or FTLD-MND/MNI (33%). To further characterize these cases, we also performed quantitative Western blots for soluble tau, APOE genotyping, and, in selected cases, tau gene sequencing. We show that soluble tau is reduced in DLDH and FTLD-MND/MNI and that APOE4 is overrepresented in PiD and DLDH. We also identified a new family with the R406W mutation and pathology consistent with NFTD. This study validates the recently proposed diagnostic criteria and forms a framework for further refinement of this classification scheme.
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Affiliation(s)
- Ryan T Mott
- Department of Pathology (Neuropathology), Duke University Medical Center, Durham, North Carolina 27710, USA
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Sergeant N, Delacourte A, Buée L. Tau protein as a differential biomarker of tauopathies. Biochim Biophys Acta Mol Basis Dis 2005; 1739:179-97. [PMID: 15615637 DOI: 10.1016/j.bbadis.2004.06.020] [Citation(s) in RCA: 197] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Accepted: 06/16/2004] [Indexed: 01/01/2023]
Abstract
Microtubule-associated Tau proteins are the basic component of intraneuronal and glial inclusions observed in many neurological disorders, the so-called tauopathies. Many etiological factors, phosphorylation, splicing, and mutations, relate Tau proteins to neurodegeneration. Molecular analysis has revealed that hyperphosphorylation and abnormal phosphorylation might be one of the important events in the process leading to tau intracellular aggregation. Specific set of pathological tau proteins exhibiting a typical biochemical pattern, and a different regional and laminar distribution, could characterize five main classes of tauopathies. A direct correlation has been established between the regional brain distribution of tau pathology and clinical symptoms; for instance progressive involvement of neocortical areas is well correlated to the severity of dementia in Alzheimer's disease, overall suggesting that pathological tau proteins are reliable marker of the neurodegenerative process. Recent discovery of tau gene mutations in frontotemporal dementia with parkinsonism linked to chromosome 17 has reinforced the predominant role attributed to tau proteins in the pathogenesis of neurodegenerative disorders, and underlined the fact that distinct sets of tau isoforms expressed in different neuronal populations could lead to different pathologies. Overall, a better knowledge of the etiological factors responsible for the aggregation of tau proteins in brain diseases is essential for development of future differential diagnosis and therapeutic strategies. They would hopefully find their application against Alzheimer's disease but also in all neurological disorders for which a dysfunction of Tau biology has been identified.
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D'Souza I, Schellenberg GD. Regulation of tau isoform expression and dementia. Biochim Biophys Acta Mol Basis Dis 2005; 1739:104-15. [PMID: 15615630 DOI: 10.1016/j.bbadis.2004.08.009] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Accepted: 08/24/2004] [Indexed: 10/26/2022]
Abstract
In the central nervous system (CNS), aberrant changes in tau mRNA splicing and consequently in protein isoform ratios cause abnormal aggregation of tau and neurodegeneration. Pathological tau causes neuronal loss in Alzheimer's disease (AD) and a diverse group of disorders called the frontotemporal dementias (FTD), which are two of the most common forms of dementia and afflict more than 10% of the elderly population. Autosomal dominant mutations in the tau gene cause frontotemporal dementia with parkinsonism-chromosome 17 type (FTDP-17). Just over half the mutations affect tau protein function and decrease its affinity for microtubules (MTs) or increase self-aggregation. The remaining mutations occur within exon 10 (E10) and intron 10 sequences and alter complex regulation of E10 splicing by multiple mechanisms. FTDP-17 splicing mutations disturb the normally balanced levels of distinct protein isoforms that result in altered biochemical and structural properties of tau. In addition to FTDP-17, altered tau isoform levels are also pathogenically associated with other FTD disorders such as progressive supranuclear palsy (PSP), corticobasal degeneration and Pick's disease; however, the mechanisms remain undefined and mutations in tau have not been detected. FTDP-17 highlights the association between splicing mutations and the pronounced variability in pathology as well as phenotype that is characteristic of inherited disorders.
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Affiliation(s)
- Ian D'Souza
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle Division, 1660 S. Columbian Way, Seattle, WA 98108, USA
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37
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Giasson BI, Lee VMY, Trojanowski JQ. Animal models of neurodegenerative dementing disorders other than Alzheimer's disease. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.cnr.2004.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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38
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Rademakers R, Cruts M, van Broeckhoven C. The role of tau (MAPT) in frontotemporal dementia and related tauopathies. Hum Mutat 2004; 24:277-95. [PMID: 15365985 DOI: 10.1002/humu.20086] [Citation(s) in RCA: 226] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Tau is a multifunctional protein that was originally identified as a microtubule-associated protein. In patients diagnosed with frontotemporal dementia and parkinsonism linked to chromosome 17, mutations in the gene encoding tau (MAPT) have been identified that disrupt the normal binding of tau to tubulin resulting in pathological deposits of hyperphosphorylated tau. Abnormal filamentous tau deposits have been reported as a pathological characteristic in several other neurodegenerative diseases, including frontotemporal dementia, Pick Disease, Alzheimer disease, argyrophilic grain disease, progressive supranuclear palsy, and corticobasal degeneration. In the last five years, extensive research has identified 34 different pathogenic MAPT mutations in 101 families worldwide. In vitro, cell-free and transfected cell studies have provided valuable information on tau dysfunction and transgenic mice carrying human MAPT mutations are being generated to study the influence of MAPT mutations in vivo. This mutation update describes the considerable differences in clinical and pathological presentation of patients with MAPT mutations and summarizes the effect of the different mutations on tau functioning. In addition, the role of tau as a genetic susceptibility factor is discussed, together with the genetic evidence for additional causal genes for tau-positive as well as tau-negative dementia.
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Affiliation(s)
- R Rademakers
- Department of Molecular Genetics, Neurogenetics Group, Flanders Interuniversity Institute for Biotechnology, University of Antwerp, Antwerpen, Belgium
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39
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Abstract
Aging is the major risk factor for numerous brain diseases. This is especially true for Alzheimer's disease (AD), a peculiar neurodegenerative disorder in that it results from the synergy of two simultaneous but distinct degenerating processes: A beta and tau pathologies. For AD, and for most neurodegenerative disorders, aggregation of full length or truncated proteins, in neurons or glial cells, or in the parenchyma, is central, but still a mystery. In addition, the late onset of these pathologies links them to ageing processes. Cause or consequence? Experimental models, that allow us to dissect these pathophysiological defects, are presented.
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Affiliation(s)
- André Delacourte
- INSERM U422, Institut de Médecine Prédictive et Recherche Thérapeutique, Place de Verdun, 59045 Lille, France
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