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LoPresti P. Tau in Oligodendrocytes Takes Neurons in Sickness and in Health. Int J Mol Sci 2018; 19:ijms19082408. [PMID: 30111714 PMCID: PMC6121290 DOI: 10.3390/ijms19082408] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/05/2018] [Accepted: 08/06/2018] [Indexed: 12/31/2022] Open
Abstract
Oligodendrocytes (OLGs), the myelin-forming cells of the central nervous system (CNS), are lifelong partners of neurons. They adjust to the functional demands of neurons over the course of a lifetime to meet the functional needs of a healthy CNS. When this functional interplay breaks down, CNS degeneration follows. OLG processes are essential features for OLGs being able to connect with the neurons. As many as fifty cellular processes from a single OLG reach and wrap an equal number of axonal segments. The cellular processes extend to meet and wrap axonal segments with myelin. Further, transport regulation, which is critical for myelination, takes place within the cellular processes. Because the microtubule-associated protein tau plays a crucial role in cellular process extension and myelination, alterations of tau in OLGs have deleterious effects, resulting in neuronal malfunction and CNS degeneration. Here, we review current concepts on the lifelong role of OLGs and myelin for brain health and plasticity. We present key studies of tau in OLGs and select important studies of tau in neurons. The extensive work on tau in neurons has considerably advanced our understanding of how tau promotes either health or disease. Because OLGs are crucial to neuronal health at any age, an understanding of the functions and regulation of tau in OLGs could uncover new therapeutics for selective CNS neurodegenerative diseases.
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Affiliation(s)
- Patrizia LoPresti
- Department of Psychology, University of Illinois at Chicago, 1007 West Harrison Street, Chicago, IL 60607, USA.
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Generation of a human induced pluripotent stem cell-based model for tauopathies combining three microtubule-associated protein TAU mutations which displays several phenotypes linked to neurodegeneration. Alzheimers Dement 2018; 14:1261-1280. [PMID: 30036493 DOI: 10.1016/j.jalz.2018.05.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 04/28/2018] [Accepted: 05/13/2018] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Tauopathies are neurodegenerative diseases characterized by TAU protein-related pathology, including frontotemporal dementia and Alzheimer's disease among others. Mutant TAU animal models are available, but none of them faithfully recapitulates human pathology and are not suitable for drug screening. METHODS To create a new in vitro tauopathy model, we generated a footprint-free triple MAPT-mutant human induced pluripotent stem cell line (N279K, P301L, and E10+16 mutations) using clustered regularly interspaced short palindromic repeats-FokI and piggyBac transposase technology. RESULTS Mutant neurons expressed pathogenic 4R and phosphorylated TAU, endogenously triggered TAU aggregation, and had increased electrophysiological activity. TAU-mutant cells presented deficiencies in neurite outgrowth, aberrant sequence of differentiation to cortical neurons, and a significant activation of stress response pathways. RNA sequencing confirmed stress activation, demonstrated a shift toward GABAergic identity, and an upregulation of neurodegenerative pathways. DISCUSSION In summary, we generated a novel in vitro human induced pluripotent stem cell TAU-mutant model displaying neurodegenerative disease phenotypes that could be used for disease modeling and drug screening.
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53
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Sarkar S. Neurofibrillary tangles mediated human neuronal tauopathies: insights from fly models. J Genet 2018. [DOI: 10.1007/s12041-018-0962-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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54
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Sarkar S. Neurofibrillary tangles mediated human neuronal tauopathies: insights from fly models. J Genet 2018; 97:783-793. [PMID: 30027909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Tauopathies represent a group of neurodegenerative disorder which are characterized by the presence of tau positive specialized argyrophilic and insoluble intraneuronal and glial fibrillar lesions known as neurofibrillary tangles (NFTs). Tau is a neuron specific microtubule binding protein which is required for the integrity and functioning of neuronal cells, and hyperphosphorylation of tau and its subsequent aggregation and paired helical filaments (PHFs) and NFTs has emerged as one of the major pathogenic mechanisms of tauopathies in human and mammalian model systems. Modeling of human tauopathies in Drosophila results in manifestation of associated phenotypes, and a recent study has demonstrated that similar to human and mammalian models, accumulation of insoluble tau aggregates in the form of typical neurotoxic NFTs triggers the pathogenesis of tauopathies in fly models. In view of the availability of remarkable genetic tools, Drosophila tau models could be extremely useful for in-depth analysis of the role of NFTs in neurodegeneration and tau aetiology, and also for the screening of novel gene(s) and molecule(s) which suppress the toxicity of tau aggregates.
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Affiliation(s)
- Surajit Sarkar
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi 110 021, India.
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55
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Sánchez MP, García-Cabrero AM, Sánchez-Elexpuru G, Burgos DF, Serratosa JM. Tau-Induced Pathology in Epilepsy and Dementia: Notions from Patients and Animal Models. Int J Mol Sci 2018; 19:ijms19041092. [PMID: 29621183 PMCID: PMC5979593 DOI: 10.3390/ijms19041092] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 03/23/2018] [Accepted: 04/03/2018] [Indexed: 12/24/2022] Open
Abstract
Patients with dementia present epilepsy more frequently than the general population. Seizures are more common in patients with Alzheimer’s disease (AD), dementia with Lewy bodies (LBD), frontotemporal dementia (FTD) and progressive supranuclear palsy (PSP) than in other dementias. Missense mutations in the microtubule associated protein tau (MAPT) gene have been found to cause familial FTD and PSP, while the P301S mutation in MAPT has been associated with early-onset fast progressive dementia and the presence of seizures. Brains of patients with AD, LBD, FTD and PSP show hyperphosphorylated tau aggregates, amyloid-β plaques and neuropil threads. Increasing evidence suggests the existence of overlapping mechanisms related to the generation of network hyperexcitability and cognitive decline. Neuronal overexpression of tau with various mutations found in FTD with parkinsonism-linked to chromosome 17 (FTDP-17) in mice produces epileptic activity. On the other hand, the use of certain antiepileptic drugs in animal models with AD prevents cognitive impairment. Further efforts should be made to search for plausible common targets for both conditions. Moreover, attempts should also be made to evaluate the use of drugs targeting tau and amyloid-β as suitable pharmacological interventions in epileptic disorders. The diagnosis of dementia and epilepsy in early stages of those diseases may be helpful for the initiation of treatments that could prevent the generation of epileptic activity and cognitive deterioration.
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Affiliation(s)
- Marina P Sánchez
- Laboratory of Neurology, IIS (Instituto Investigación Sanitaria/Health Research Institute)-Jiménez Díaz Foundation, UAM (Universidad Autonoma de Madrid/Autonomous University of Madrid) and Biomedical Research Network Center on Rare Diseases (CIBERER), 28045 Madrid, Spain.
| | - Ana M García-Cabrero
- Laboratory of Neurology, IIS (Instituto Investigación Sanitaria/Health Research Institute)-Jiménez Díaz Foundation, UAM (Universidad Autonoma de Madrid/Autonomous University of Madrid) and Biomedical Research Network Center on Rare Diseases (CIBERER), 28045 Madrid, Spain.
- Department of Immunology and Oncology and Protein Tools Unit, Biotechnology National Center (CNB/CSIC), 28049 Madrid, Spain.
| | - Gentzane Sánchez-Elexpuru
- Laboratory of Neurology, IIS (Instituto Investigación Sanitaria/Health Research Institute)-Jiménez Díaz Foundation, UAM (Universidad Autonoma de Madrid/Autonomous University of Madrid) and Biomedical Research Network Center on Rare Diseases (CIBERER), 28045 Madrid, Spain.
| | - Daniel F Burgos
- Laboratory of Neurology, IIS (Instituto Investigación Sanitaria/Health Research Institute)-Jiménez Díaz Foundation, UAM (Universidad Autonoma de Madrid/Autonomous University of Madrid) and Biomedical Research Network Center on Rare Diseases (CIBERER), 28045 Madrid, Spain.
| | - José M Serratosa
- Laboratory of Neurology, IIS (Instituto Investigación Sanitaria/Health Research Institute)-Jiménez Díaz Foundation, UAM (Universidad Autonoma de Madrid/Autonomous University of Madrid) and Biomedical Research Network Center on Rare Diseases (CIBERER), 28045 Madrid, Spain.
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Kundel F, Tosatto L, Whiten DR, Wirthensohn DC, Horrocks MH, Klenerman D. Shedding light on aberrant interactions - a review of modern tools for studying protein aggregates. FEBS J 2018; 285:3604-3630. [PMID: 29453901 DOI: 10.1111/febs.14409] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/27/2018] [Accepted: 02/12/2018] [Indexed: 12/15/2022]
Abstract
The link between protein aggregation and neurodegenerative disease is well established. However, given the heterogeneity of species formed during the aggregation process, it is difficult to delineate details of the molecular events involved in generating pathological aggregates from those producing soluble monomers. As aberrant aggregates are possible pharmacological targets for the treatment of neurodegenerative diseases, the need to observe and characterise soluble oligomers has pushed traditional biophysical techniques to their limits, leading to the development of a plethora of new tools capable of detecting soluble oligomers with high precision and specificity. In this review, we discuss a range of modern biophysical techniques that have been developed to study protein aggregation, and give an overview of how they have been used to understand, in detail, the aberrant aggregation of amyloidogenic proteins associated with the two most common neurodegenerative disorders, Alzheimer's disease and Parkinson's disease.
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Affiliation(s)
| | - Laura Tosatto
- Centre for Integrative Biology, Università degli Studi di Trento, Italy
| | | | | | | | - David Klenerman
- Department of Chemistry, University of Cambridge, UK.,UK Dementia Research Institute, University of Cambridge, UK
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Sun L, Chen K, Li X, Xiao S. Rapidly Progressive Frontotemporal Dementia Associated with MAPT Mutation G389R. J Alzheimers Dis 2018; 55:777-785. [PMID: 27802239 DOI: 10.3233/jad-160802] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Frontotemporal dementia includes a large spectrum of neurodegenerative disorders. Here, we report the case of a young patient with MAPT mutation G389R, who was 27 years old when he progressively developed severe behavioral disturbances. Initially, he presented with slowly progressive personality change. After 1 year, he exhibited moderate dementia with extrapyramidal and pyramidal symptoms. MRI showed frontotemporal atrophy. He rapidly progressed to severe dementia 3 years after onset. Genetic testing revealed a heterozygous guanine to cytosine mutation at the first base of codon 389 (c.1165G>A) of MAPT, the tau gene, resulting in a glycine to arginine substitution in the patient and two unaffected relatives. We predicted the model of mutant tau protein through I-TASSER software, and speculated the structural change of tau protein caused by mutant site. We also detected the MAPT gene transcript and methylation of samples from peripheral blood leucocytes in an attempt to explain the possible mechanisms of incomplete penetrance, although there were not positive findings. This case is remarkable because of the early onset and rapid progression of the disease.
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Affiliation(s)
- Lin Sun
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Kathryn Chen
- Department of Psychiatry and Behavioral Sciences, University of Washington, WA, USA
| | - Xia Li
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shifu Xiao
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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58
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DeVos SL, Miller RL, Schoch KM, Holmes BB, Kebodeaux CS, Wegener AJ, Chen G, Shen T, Tran H, Nichols B, Zanardi TA, Kordasiewicz HB, Swayze EE, Bennett CF, Diamond MI, Miller TM. Tau reduction prevents neuronal loss and reverses pathological tau deposition and seeding in mice with tauopathy. Sci Transl Med 2018; 9:9/374/eaag0481. [PMID: 28123067 DOI: 10.1126/scitranslmed.aag0481] [Citation(s) in RCA: 308] [Impact Index Per Article: 51.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 05/13/2016] [Accepted: 11/17/2016] [Indexed: 12/14/2022]
Abstract
Accumulation of hyperphosphorylated tau directly correlates with cognitive decline in Alzheimer's disease and other primary tauopathies. One therapeutic strategy may be to reduce total tau expression. We identified antisense oligonucleotides (ASOs) that selectively decreased human tau mRNA and protein in mice expressing mutant P301S human tau. After reduction of human tau in this mouse model of tauopathy, fewer tau inclusions developed, and preexisting phosphorylated tau and Thioflavin S pathology were reversed. The resolution of tau pathology was accompanied by the prevention of hippocampal volume loss, neuronal death, and nesting deficits. In addition, mouse survival was extended, and pathological tau seeding was reversed. In nonhuman primates, tau ASOs distributed throughout the brain and spinal cord and reduced tau mRNA and protein in the brain, spinal cord, and cerebrospinal fluid. These data support investigation of a tau-lowering therapy in human patients who have tau-positive inclusions even after pathological tau deposition has begun.
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Affiliation(s)
- Sarah L DeVos
- Department of Neurology, Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Rebecca L Miller
- Department of Neurology, Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Kathleen M Schoch
- Department of Neurology, Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Brandon B Holmes
- Department of Neurology, Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Carey S Kebodeaux
- Department of Neurology, Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Amy J Wegener
- Department of Neurology, Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Guo Chen
- Department of Neurology, Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Tao Shen
- Department of Neurology, Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Hien Tran
- Ionis Pharmaceuticals, Carlsbad, CA 90201, USA
| | | | | | | | | | | | - Marc I Diamond
- Center for Alzheimer's and Neurodegenerative Diseases, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Timothy M Miller
- Department of Neurology, Hope Center for Neurological Disorders, Washington University in St. Louis, St. Louis, MO 63110, USA.
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Rey NL, Wesson DW, Brundin P. The olfactory bulb as the entry site for prion-like propagation in neurodegenerative diseases. Neurobiol Dis 2018; 109:226-248. [PMID: 28011307 PMCID: PMC5972535 DOI: 10.1016/j.nbd.2016.12.013] [Citation(s) in RCA: 183] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/13/2016] [Accepted: 12/15/2016] [Indexed: 02/07/2023] Open
Abstract
Olfactory deficits are present in numerous neurodegenerative disorders and are accompanied by pathology in related brain regions. In several of these disorders, olfactory disturbances appear early and are considered as prodromal symptoms of the disease. In addition, pathological protein aggregates affect olfactory regions prior to other regions, suggesting that the olfactory system might be particularly vulnerable to neurodegenerative diseases. Exposed to the external environment, the olfactory epithelium and olfactory bulb allow pathogen and toxin penetration into the brain, a process that has been proposed to play a role in neurodegenerative diseases. Determining whether the olfactory bulb could be a starting point of pathology and of pathology spread is crucial to understanding how neurodegenerative diseases evolve. We argue that pathological changes following environmental insults contribute to the initiation of protein aggregation in the olfactory bulb, which then triggers the spread of the pathology within the brain by a templating mechanism in a prion-like manner. We review the evidence for the early involvement of olfactory structures in neurodegenerative diseases and the relationship between neuropathology and olfactory function. We discuss the vulnerability and putative underlying mechanisms by which pathology could be initiated in the olfactory bulb, from the entry of pathogens (promoted by increased permeability of the olfactory epithelium with aging or inflammation) to the sensitivity of the olfactory system to oxidative stress and inflammation. Finally, we review changes in protein expression and neural excitability triggered by pathogenic proteins that can promote pathogenesis in the olfactory bulb and beyond.
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Affiliation(s)
- Nolwen L Rey
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA.
| | - Daniel W Wesson
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Patrik Brundin
- Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
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Pawlowski M, Lueg G, Gross CC, Johnen A, Krämer J, Weckesser M, Wiendl H, Meuth SG, Duning T. Relevance of raised cerebrospinal fluid monocyte levels in patients with frontotemporal dementia. Neurobiol Aging 2017; 62:45-52. [PMID: 29107846 DOI: 10.1016/j.neurobiolaging.2017.09.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 09/27/2017] [Accepted: 09/29/2017] [Indexed: 12/11/2022]
Abstract
Frontotemporal dementia (FTD) is a heterogeneous neurodegenerative disorder. The contribution of the immune system to its pathogenesis remains incompletely understood. In this study, we performed comprehensive immune cell profiling in the cerebrospinal fluid (CSF) and peripheral blood of patients with FTD. Thirty-two patients with behavioral variant frontotemporal dementia and 25 patients with primary progressive aphasia were included and compared to 14 healthy elderly controls. All patients underwent neuropsychological examination, magnetic resonance imaging, voxel-based diffusion tensor imaging, and peripheral blood and CSF immune cell profiling by multiparameter flow cytometry. The percentage of CSF monocytes was significantly increased specifically in patients with primary progressive aphasia. The proportion of monocytes in the CSF of the total FTD patient group directly correlated with semantic language impairment and microstructural temporal lesions. Increased intrathecal numbers of monocytes suggest a specific response of the innate immune system in a subset of patients with FTD. The findings are of clinical relevance since monocyte levels in the CSF were correlated with typical neuropsychological deficits and microstructural patterns of temporal degeneration.
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Affiliation(s)
| | - Gero Lueg
- Department of Neurology, University Hospital Münster, Münster, Germany
| | - Catharina C Gross
- Department of Neurology, University Hospital Münster, Münster, Germany
| | - Andreas Johnen
- Department of Neurology, University Hospital Münster, Münster, Germany
| | - Julia Krämer
- Department of Neurology, University Hospital Münster, Münster, Germany
| | - Matthias Weckesser
- Department of Nuclear Medicine, University Hospital Münster, Münster, Germany
| | - Heinz Wiendl
- Department of Neurology, University Hospital Münster, Münster, Germany
| | - Sven G Meuth
- Department of Neurology, University Hospital Münster, Münster, Germany
| | - Thomas Duning
- Department of Neurology, University Hospital Münster, Münster, Germany.
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61
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Zempel H, Dennissen FJA, Kumar Y, Luedtke J, Biernat J, Mandelkow EM, Mandelkow E. Axodendritic sorting and pathological missorting of Tau are isoform-specific and determined by axon initial segment architecture. J Biol Chem 2017; 292:12192-12207. [PMID: 28536263 DOI: 10.1074/jbc.m117.784702] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 05/21/2017] [Indexed: 11/06/2022] Open
Abstract
Subcellular mislocalization of the microtubule-associated protein Tau is a hallmark of Alzheimer disease (AD) and other tauopathies. Six Tau isoforms, differentiated by the presence or absence of a second repeat or of N-terminal inserts, exist in the human CNS, but their physiological and pathological differences have long remained elusive. Here, we investigated the properties and distributions of human and rodent Tau isoforms in primary forebrain rodent neurons. We found that the Tau diffusion barrier (TDB), located within the axon initial segment (AIS), controls retrograde (axon-to-soma) and anterograde (soma-to-axon) traffic of Tau. Tau isoforms without the N-terminal inserts were sorted efficiently into the axon. However, the longest isoform (2N4R-Tau) was partially retained in cell bodies and dendrites, where it accelerated spine and dendrite growth. The TDB (located within the AIS) was impaired when AIS components (ankyrin G, EB1) were knocked down or when glycogen synthase kinase-3β (GSK3β; an AD-associated kinase tethered to the AIS) was overexpressed. Using superresolution nanoscopy and live-cell imaging, we observed that microtubules within the AIS appeared highly dynamic, a feature essential for the TDB. Pathomechanistically, amyloid-β insult caused cofilin activation and F-actin remodeling and decreased microtubule dynamics in the AIS. Concomitantly with these amyloid-β-induced disruptions, the AIS/TDB sorting function failed, causing AD-like Tau missorting. In summary, we provide evidence that the human and rodent Tau isoforms differ in axodendritic sorting and amyloid-β-induced missorting and that the axodendritic distribution of Tau depends on AIS integrity.
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Affiliation(s)
- Hans Zempel
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany; CAESAR Research Center, 53175 Bonn, Germany; Max Planck Institute for Metabolism Research, 50931 Cologne, Germany; University of Bonn, 53113 Bonn, Germany.
| | - Frank J A Dennissen
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany; CAESAR Research Center, 53175 Bonn, Germany
| | - Yatender Kumar
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany; Max Planck Institute for Metabolism Research, 50931 Cologne, Germany
| | - Julia Luedtke
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany; CAESAR Research Center, 53175 Bonn, Germany
| | - Jacek Biernat
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany; CAESAR Research Center, 53175 Bonn, Germany
| | - Eva-Maria Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany; CAESAR Research Center, 53175 Bonn, Germany; Max Planck Institute for Metabolism Research, 50931 Cologne, Germany
| | - Eckhard Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany; CAESAR Research Center, 53175 Bonn, Germany; Max Planck Institute for Metabolism Research, 50931 Cologne, Germany.
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62
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Faulty RNA splicing: consequences and therapeutic opportunities in brain and muscle disorders. Hum Genet 2017; 136:1215-1235. [DOI: 10.1007/s00439-017-1802-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 04/13/2017] [Indexed: 12/12/2022]
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63
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64
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Raefsky SM, Mattson MP. Adaptive responses of neuronal mitochondria to bioenergetic challenges: Roles in neuroplasticity and disease resistance. Free Radic Biol Med 2017; 102:203-216. [PMID: 27908782 PMCID: PMC5209274 DOI: 10.1016/j.freeradbiomed.2016.11.045] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 11/27/2016] [Indexed: 01/04/2023]
Abstract
An important concept in neurobiology is "neurons that fire together, wire together" which means that the formation and maintenance of synapses is promoted by activation of those synapses. Very similar to the effects of the stress of exercise on muscle cells, emerging findings suggest that neurons respond to activity by activating signaling pathways (e.g., Ca2+, CREB, PGC-1α, NF-κB) that stimulate mitochondrial biogenesis and cellular stress resistance. These pathways are also activated by aerobic exercise and food deprivation, two bioenergetic challenges of fundamental importance in the evolution of the brains of all mammals, including humans. The metabolic 'switch' in fuel source from liver glycogen store-derived glucose to adipose cell-derived fatty acids and their ketone metabolites during fasting and sustained exercise, appears to be a pivotal trigger of both brain-intrinsic and peripheral organ-derived signals that enhance learning and memory and underlying synaptic plasticity and neurogenesis. Brain-intrinsic extracellular signals include the excitatory neurotransmitter glutamate and the neurotrophic factor BDNF, and peripheral signals may include the liver-derived ketone 3-hydroxybutyrate and the muscle cell-derived protein irisin. Emerging findings suggest that fasting, exercise and an intellectually challenging lifestyle can protect neurons against the dysfunction and degeneration that they would otherwise suffer in acute brain injuries (stroke and head trauma) and neurodegenerative disorders including Alzheimer's, Parkinson's and Huntington's disease. Among the prominent intracellular responses of neurons to these bioenergetic challenges are up-regulation of antioxidant defenses, autophagy/mitophagy and DNA repair. A better understanding of such fundamental hormesis-based adaptive neuronal response mechanisms is expected to result in the development and implementation of novel interventions to promote optimal brain function and healthy brain aging.
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Affiliation(s)
- Sophia M Raefsky
- Laboratory of Neurosciences, National Institute on Aging, Baltimore, MD 21224, United States
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging, Baltimore, MD 21224, United States; Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States.
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65
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Monti C, Colugnat I, Lopiano L, Chiò A, Alberio T. Network Analysis Identifies Disease-Specific Pathways for Parkinson's Disease. Mol Neurobiol 2016; 55:370-381. [PMID: 28004338 DOI: 10.1007/s12035-016-0326-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 11/29/2016] [Indexed: 12/13/2022]
Abstract
Neurodegenerative diseases are characterized by the progressive loss of specific neurons in selected regions of the central nervous system. The main clinical manifestation (movement disorders, cognitive impairment, and/or psychiatric disturbances) depends on the neuron population being primarily affected. Parkinson's disease is a common movement disorder, whose etiology remains mostly unknown. Progressive loss of dopaminergic neurons in the substantia nigra causes an impairment of the motor control. Some of the pathogenetic mechanisms causing the progressive deterioration of these neurons are not specific for Parkinson's disease but are shared by other neurodegenerative diseases, like Alzheimer's disease and amyotrophic lateral sclerosis. Here, we performed a meta-analysis of the literature of all the quantitative proteomic investigations of neuronal alterations in different models of Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis to distinguish between general and Parkinson's disease-specific pattern of neurodegeneration. Then, we merged proteomics data with genetics information from the DisGeNET database. The comparison of gene and protein information allowed us to identify 25 proteins involved uniquely in Parkinson's disease and we verified the alteration of one of them, i.e., transaldolase 1 (TALDO1), in the substantia nigra of 5 patients. By using open-source bioinformatics tools, we identified the biological processes specifically affected in Parkinson's disease, i.e., proteolysis, mitochondrion organization, and mitophagy. Eventually, we highlighted four cellular component complexes mostly involved in the pathogenesis: the proteasome complex, the protein phosphatase 2A, the chaperonins CCT complex, and the complex III of the respiratory chain.
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Affiliation(s)
- Chiara Monti
- Laboratory of Biochemistry and Functional Proteomics, Department of Science and High Technology, University of Insubria, via Manara,7, I-21052, Busto Arsizio, VA, Italy.,Center of Neuroscience, University of Insubria, Busto Arsizio, Italy
| | - Ilaria Colugnat
- Laboratory of Biochemistry and Functional Proteomics, Department of Science and High Technology, University of Insubria, via Manara,7, I-21052, Busto Arsizio, VA, Italy
| | - Leonardo Lopiano
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy
| | - Adriano Chiò
- 'Rita Levi Montalcini' Department of Neuroscience, University of Turin, Turin, Italy
| | - Tiziana Alberio
- Laboratory of Biochemistry and Functional Proteomics, Department of Science and High Technology, University of Insubria, via Manara,7, I-21052, Busto Arsizio, VA, Italy. .,Center of Neuroscience, University of Insubria, Busto Arsizio, Italy.
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66
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Arendt T, Stieler JT, Holzer M. Tau and tauopathies. Brain Res Bull 2016; 126:238-292. [DOI: 10.1016/j.brainresbull.2016.08.018] [Citation(s) in RCA: 333] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/31/2016] [Accepted: 08/31/2016] [Indexed: 12/11/2022]
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67
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Xiao T, Jiao B, Zhang W, Pan C, Wei J, Liu X, Zhou Y, Zhou L, Tang B, Shen L. Identification of CHCHD10 Mutation in Chinese Patients with Alzheimer Disease. Mol Neurobiol 2016; 54:5243-5247. [PMID: 27578015 DOI: 10.1007/s12035-016-0056-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Accepted: 08/15/2016] [Indexed: 01/27/2023]
Abstract
CHCHD10 gene has been identified to be associated with frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Considering the clinical phenotype and pathology characterization were overlapped between FTD and Alzheimer disease (AD), and so far, no systematic analysis of CHCHD10 mutation was conducted in patients with AD in Asian population. Therefore, we screened of all exons in CHCHD10 in a cohort of 484 AD patients (60 with family history) from Mainland China. A heterozygous variant p.A35D (c.104C>A), previously reported in a patient with FTD in Italian population, was identified in a female patient with sporadic LOAD. The age at onset of mutation carrier was 86, presented as typical amnestic dementia. The mutation was found to be deleterious according to in silico predictions and excluded in 500 ethnically and geographically matched controls. Our finding revealed the clinical manifestations of variant p.A35D (c.104C>A) in a LOAD case and indicated that CHCHD10 mutation was presented in different types of dementia.
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Affiliation(s)
- Tingting Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Bin Jiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Weiwei Zhang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Chuzheng Pan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Jingya Wei
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Xiaoyan Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Yafang Zhou
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
| | - Lin Zhou
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China.,State Key Laboratory of Medical Genetics, Changsha, China
| | - Lu Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China. .,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China. .,State Key Laboratory of Medical Genetics, Changsha, China.
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68
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Bodea L, Eckert A, Ittner LM, Piguet O, Götz J. Tau physiology and pathomechanisms in frontotemporal lobar degeneration. J Neurochem 2016; 138 Suppl 1:71-94. [PMID: 27306859 PMCID: PMC5094566 DOI: 10.1111/jnc.13600] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 01/31/2016] [Accepted: 02/24/2016] [Indexed: 12/27/2022]
Abstract
Frontotemporal lobar degeneration (FTLD) has been associated with toxic intracellular aggregates of hyperphosphorylated tau (FTLD-tau). Moreover, genetic studies identified mutations in the MAPT gene encoding tau in familial cases of the disease. In this review, we cover a range of aspects of tau function, both in the healthy and diseased brain, discussing several in vitro and in vivo models. Tau structure and function in the healthy brain is presented, accentuating its distinct compartmentalization in neurons and its role in microtubule stabilization and axonal transport. Furthermore, tau-driven pathology is discussed, introducing current concepts and the underlying experimental evidence. Different aspects of pathological tau phosphorylation, the protein's genomic and domain organization as well as its spreading in disease, together with MAPT-associated mutations and their respective models are presented. Dysfunction related to other post-transcriptional modifications and their effect on normal neuronal functions such as cell cycle, epigenetics and synapse dynamics are also discussed, providing a mechanistic explanation for the observations made in FTLD-tau cases, with the possibility for therapeutic intervention. In this review, we cover aspects of tau function, both in the healthy and diseased brain, referring to different in vitro and in vivo models. In healthy neurons, tau is compartmentalized, with higher concentrations found in the distal part of the axon. Cargo molecules are sensitive to this gradient. A disturbed tau distribution, as found in frontotemporal lobar degeneration (FTLD-tau), has severe consequences for cellular physiology: tau accumulates in the neuronal soma and dendrites, leading among others to microtubule depolymerization and impaired axonal transport. Tau forms insoluble aggregates that sequester additional molecules stalling cellular physiology. Neuronal communication is gradually lost as toxic tau accumulates in dendritic spines with subsequent degeneration of synapses and synaptic loss. Thus, by providing a mechanistic explanation for the observations made in FTLD-tau cases, arises a possibility for therapeutic interventions. This article is part of the Frontotemporal Dementia special issue.
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Affiliation(s)
- Liviu‐Gabriel Bodea
- Clem Jones Centre for Ageing Dementia ResearchQueensland Brain InstituteThe University of QueenslandBrisbaneQLDAustralia
| | - Anne Eckert
- Neurobiology LaboratoryPsychiatric University Clinics BaselUniversity of BaselBaselSwitzerland
| | - Lars Matthias Ittner
- Dementia Research UnitSchool of Medical SciencesFaculty of MedicineUniversity of New South WalesSydneyNSWAustralia
| | | | - Jürgen Götz
- Clem Jones Centre for Ageing Dementia ResearchQueensland Brain InstituteThe University of QueenslandBrisbaneQLDAustralia
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69
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Lee SH, Le Pichon CE, Adolfsson O, Gafner V, Pihlgren M, Lin H, Solanoy H, Brendza R, Ngu H, Foreman O, Chan R, Ernst JA, DiCara D, Hotzel I, Srinivasan K, Hansen DV, Atwal J, Lu Y, Bumbaca D, Pfeifer A, Watts RJ, Muhs A, Scearce-Levie K, Ayalon G. Antibody-Mediated Targeting of Tau In Vivo Does Not Require Effector Function and Microglial Engagement. Cell Rep 2016; 16:1690-1700. [PMID: 27475227 DOI: 10.1016/j.celrep.2016.06.099] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 05/27/2016] [Accepted: 06/29/2016] [Indexed: 02/03/2023] Open
Abstract
The spread of tau pathology correlates with cognitive decline in Alzheimer's disease. In vitro, tau antibodies can block cell-to-cell tau spreading. Although mechanisms of anti-tau function in vivo are unknown, effector function might promote microglia-mediated clearance. In this study, we investigated whether antibody effector function is required for targeting tau. We compared efficacy in vivo and in vitro of two versions of the same tau antibody, with and without effector function, measuring tau pathology, neuron health, and microglial function. Both antibodies reduced accumulation of tau pathology in Tau-P301L transgenic mice and protected cultured neurons against extracellular tau-induced toxicity. Only the full-effector antibody enhanced tau uptake in cultured microglia, which promoted release of proinflammatory cytokines. In neuron-microglia co-cultures, only effectorless anti-tau protected neurons, suggesting full-effector tau antibodies can induce indirect toxicity via microglia. We conclude that effector function is not required for efficacy, and effectorless tau antibodies may represent a safer approach to targeting tau.
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Affiliation(s)
| | | | | | | | | | - Han Lin
- Genentech, South San Francisco, CA 94080, USA
| | | | | | - Hai Ngu
- Genentech, South San Francisco, CA 94080, USA
| | | | - Ruby Chan
- Genentech, South San Francisco, CA 94080, USA
| | | | | | | | | | | | | | - Yanmei Lu
- Genentech, South San Francisco, CA 94080, USA
| | | | | | | | | | | | - Gai Ayalon
- Genentech, South San Francisco, CA 94080, USA.
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70
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Regan P, Whitcomb DJ, Cho K. Physiological and Pathophysiological Implications of Synaptic Tau. Neuroscientist 2016; 23:137-151. [DOI: 10.1177/1073858416633439] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Tauopathies encompass a broad range of neurodegenerative diseases featuring extensive neuronal death and cognitive decline. However, research over the past 30 years has failed to significantly advance our understanding of how tau causes dementia, limiting the design of rational therapeutics. It has become evident that we need to expand our understanding of tau in physiology, in order to delineate how tau may contribute to pathology. This review discusses recent evidence that has uncovered a novel aspect of tau function, based on its previously uncharacterized localization to the synapse. Here, multiple streams of evidence support a critical role for synaptic tau in the regulation of synapse physiology. In particular, long-term depression, a form of synaptic weakening, is dependent on the presence of tau in hippocampal neurons. The regulation of tau by specific phosphorylation events downstream of GSK-3β activation appears to be integral to this signaling role. We also describe how the regulation of synapse physiology by tau and its phosphorylation may inform our understanding of tauopathies and comorbid diseases. This work should provide a platform for future tau biology research in addition to therapeutic design.
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Affiliation(s)
- Philip Regan
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology (HW-LINE), Bristol, UK
| | - Daniel J. Whitcomb
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology (HW-LINE), Bristol, UK
- Centre for Synaptic Plasticity, Faculty of Health Sciences, University of Bristol, Bristol, UK
| | - Kwangwook Cho
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology (HW-LINE), Bristol, UK
- Centre for Synaptic Plasticity, Faculty of Health Sciences, University of Bristol, Bristol, UK
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71
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Berryessa CM. Behavioral and neural impairments of frontotemporal dementia: Potential implications for criminal responsibility and sentencing. INTERNATIONAL JOURNAL OF LAW AND PSYCHIATRY 2016; 46:1-6. [PMID: 27039661 DOI: 10.1016/j.ijlp.2016.02.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Individuals in the early stages of the behavioral variant of frontotemporal dementia (bvFTD), a progressive neurodegenerative disorder marked by atrophy to the brain's frontal regions, exhibit severe disturbances to social and moral processing and decision-making after the onset of the disorder. These behavioral impairments, underlain by the neural deficits associated with the disorder, can often lead individuals with bvFTD to criminally offend. As such, behavioral and frontotemporal lobe abnormalities exhibited by offenders with bvFTD potentially represent several complex challenges for the legal system. This paper examines some of the ways in which the behavioral and neural impairments associated with bvFTD may influence issues surrounding the criminal responsibility, specifically legal insanity, and sentencing of offenders with bvFTD in the U.S. legal system. As there is very little literature in these areas concerning bvFTD, the existing academic dialogue on psychopathy, a disorder with similar behavioral symptoms and neural deficits, is used to frame the discussion on these issues.
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Affiliation(s)
- Colleen M Berryessa
- Department of Criminology, University of Pennsylvania, 483 McNeil Building, 3718 Locust Walk, Philadelphia, PA 19104, USA.
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72
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Hasegawa M. Molecular Mechanisms in the Pathogenesis of Alzheimer's disease and Tauopathies-Prion-Like Seeded Aggregation and Phosphorylation. Biomolecules 2016; 6:biom6020024. [PMID: 27136595 PMCID: PMC4919919 DOI: 10.3390/biom6020024] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 04/19/2016] [Accepted: 04/22/2016] [Indexed: 12/14/2022] Open
Abstract
Neurofibrillary tau pathology (tangles and threads) and extracellular amyloid-β (Aβ) pathology are defining features of Alzheimer’s disease. For 25 years, most research has focused on the amyloid hypothesis of AD pathogenesis and progression. But, because of failures in clinical trials of Aβ-targeted therapies and the new concept of prion-like propagation of intracellular abnormal proteins, tau has come back into the spotlight as a candidate therapeutic target in AD. Tau pathologies are found in a range of neurodegenerative disorders, but extensive analyses of pathological tau in diseased brains has demonstrated that the abnormal tau protein in each disease is structurally distinct, supporting the idea that progression of the diverse but characteristic tau pathologies occurs through prion-like seed-dependent aggregation. Therefore, intervention in the conversion of normal tau to abnormal forms and in cell-to-cell transmission of tau may be the key to development of disease-modifying therapies for AD and other dementing disorders.
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Affiliation(s)
- Masato Hasegawa
- Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science; Setagaya-ku 156-8506, Japan.
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73
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Koss DJ, Robinson L, Drever BD, Plucińska K, Stoppelkamp S, Veselcic P, Riedel G, Platt B. Mutant Tau knock-in mice display frontotemporal dementia relevant behaviour and histopathology. Neurobiol Dis 2016; 91:105-23. [PMID: 26949217 DOI: 10.1016/j.nbd.2016.03.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 02/26/2016] [Accepted: 03/02/2016] [Indexed: 10/22/2022] Open
Abstract
Models of Tau pathology related to frontotemporal dementia (FTD) are essential to determine underlying neurodegenerative pathologies and resulting tauopathy relevant behavioural changes. However, existing models are often limited in their translational value due to Tau overexpression, and the frequent occurrence of motor deficits which prevent comprehensive behavioural assessments. In order to address these limitations, a forebrain-specific (CaMKIIα promoter), human mutated Tau (hTauP301L+R406W) knock-in mouse was generated out of the previously characterised PLB1Triple mouse, and named PLB2Tau. After confirmation of an additional hTau species (~60kDa) in forebrain samples, we identified age-dependent progressive Tau phosphorylation which coincided with the emergence of FTD relevant behavioural traits. In line with the non-cognitive symptomatology of FTD, PLB2Tau mice demonstrated early emerging (~6months) phenotypes of heightened anxiety in the elevated plus maze, depressive/apathetic behaviour in a sucrose preference test and generally reduced exploratory activity in the absence of motor impairments. Investigations of cognitive performance indicated prominent dysfunctions in semantic memory, as assessed by social transmission of food preference, and in behavioural flexibility during spatial reversal learning in a home cage corner-learning task. Spatial learning was only mildly affected and task-specific, with impairments at 12months of age in the corner learning but not in the water maze task. Electroencephalographic (EEG) investigations indicated a vigilance-stage specific loss of alpha power during wakefulness at both parietal and prefrontal recording sites, and site-specific EEG changes during non-rapid eye movement sleep (prefrontal) and rapid eye movement sleep (parietal). Further investigation of hippocampal electrophysiology conducted in slice preparations indicated a modest reduction in efficacy of synaptic transmission in the absence of altered synaptic plasticity. Together, our data demonstrate that the transgenic PLB2Tau mouse model presents with a striking behavioural and physiological face validity relevant for FTD, driven by the low level expression of mutant FTD hTau.
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Affiliation(s)
- David J Koss
- School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Lianne Robinson
- School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Benjamin D Drever
- School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Kaja Plucińska
- School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Sandra Stoppelkamp
- School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Peter Veselcic
- School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Gernot Riedel
- School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
| | - Bettina Platt
- School of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
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74
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Maeda S, Djukic B, Taneja P, Yu GQ, Lo I, Davis A, Craft R, Guo W, Wang X, Kim D, Ponnusamy R, Gill TM, Masliah E, Mucke L. Expression of A152T human tau causes age-dependent neuronal dysfunction and loss in transgenic mice. EMBO Rep 2016; 17:530-51. [PMID: 26931567 PMCID: PMC4818780 DOI: 10.15252/embr.201541438] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 01/13/2016] [Indexed: 11/24/2022] Open
Abstract
A152T‐variant human tau (hTau‐A152T) increases risk for tauopathies, including Alzheimer's disease. Comparing mice with regulatable expression of hTau‐A152T or wild‐type hTau (hTau‐WT), we find age‐dependent neuronal loss, cognitive impairments, and spontaneous nonconvulsive epileptiform activity primarily in hTau‐A152T mice. However, overexpression of either hTau species enhances neuronal responses to electrical stimulation of synaptic inputs and to an epileptogenic chemical. hTau‐A152T mice have higher hTau protein/mRNA ratios in brain, suggesting that A152T increases production or decreases clearance of hTau protein. Despite their functional abnormalities, aging hTau‐A152T mice show no evidence for accumulation of insoluble tau aggregates, suggesting that their dysfunctions are caused by soluble tau. In human amyloid precursor protein (hAPP) transgenic mice, co‐expression of hTau‐A152T enhances risk of early death and epileptic activity, suggesting copathogenic interactions between hTau‐A152T and amyloid‐β peptides or other hAPP metabolites. Thus, the A152T substitution may augment risk for neurodegenerative diseases by increasing hTau protein levels, promoting network hyperexcitability, and synergizing with the adverse effects of other pathogenic factors.
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Affiliation(s)
- Sumihiro Maeda
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Biljana Djukic
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | - Praveen Taneja
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | - Gui-Qiu Yu
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | - Iris Lo
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | - Allyson Davis
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | - Ryan Craft
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | - Weikun Guo
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | - Xin Wang
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | - Daniel Kim
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | | | - T Michael Gill
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | - Eliezer Masliah
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA Department of Pathology, University of California, San Diego, La Jolla, CA, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
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75
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Valera E, Spencer B, Masliah E. Immunotherapeutic Approaches Targeting Amyloid-β, α-Synuclein, and Tau for the Treatment of Neurodegenerative Disorders. Neurotherapeutics 2016; 13:179-89. [PMID: 26494242 PMCID: PMC4720672 DOI: 10.1007/s13311-015-0397-z] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Disease-modifying alternatives are sorely needed for the treatment of neurodegenerative disorders, a group of diseases that afflict approximately 50 million Americans annually. Immunotherapy is one of the most developed approaches in this direction. Vaccination against amyloid-β, α-synuclein, or tau has been extensively explored, specially as the discovery that these proteins may propagate cell-to-cell and be accessible to antibodies when embedded into the plasma membrane or in the extracellular space. Likewise, the use of passive immunization approaches with specific antibodies against abnormal conformations of these proteins has also yielded promising results. The clinical development of immunotherapies for Alzheimer’s disease, Parkinson’s disease, frontotemporal dementia, dementia with Lewy bodies, and other neurodegenerative disorders is a field in constant evolution. Results to date suggest that immunotherapy is a promising therapeutic approach for neurodegenerative diseases that progress with the accumulation and prion-like propagation of toxic protein aggregates. Here we provide an overview of the most novel and relevant immunotherapeutic advances targeting amyloid-β in Alzheimer’s disease, α-synuclein in Alzheimer’s disease and Parkinson’s disease, and tau in Alzheimer’s disease and frontotemporal dementia.
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Affiliation(s)
- Elvira Valera
- grid.266100.30000000121074242Department of Neurosciences, University of California, La Jolla, San Diego, CA 92093 USA
| | - Brian Spencer
- grid.266100.30000000121074242Department of Neurosciences, University of California, La Jolla, San Diego, CA 92093 USA
| | - Eliezer Masliah
- grid.266100.30000000121074242Department of Neurosciences, University of California, La Jolla, San Diego, CA 92093 USA
- grid.266100.30000000121074242Department of Pathology, University of California, La Jolla, San Diego, CA 92093 USA
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76
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Walter J. The Triggering Receptor Expressed on Myeloid Cells 2: A Molecular Link of Neuroinflammation and Neurodegenerative Diseases. J Biol Chem 2015; 291:4334-41. [PMID: 26694609 DOI: 10.1074/jbc.r115.704981] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The triggering receptor expressed on myeloid cells (TREM) 2 is a member of the immunoglobulin superfamily of receptors and mediates signaling in immune cells via engagement of its co-receptor DNAX-activating protein of 12 kDa (DAP12). Homozygous mutations in TREM2 or DAP12 cause Nasu-Hakola disease, which is characterized by bone abnormalities and dementia. Recently, a variant of TREM2 has also been associated with an increased risk for Alzheimer disease. The selective expression of TREM2 on immune cells and its association with different forms of dementia indicate a contribution of this receptor in common pathways of neurodegeneration.
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Affiliation(s)
- Jochen Walter
- From the Department of Neurology, University of Bonn, 53127 Bonn, Germany
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77
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Xu L, Ryu J, Nguyen JV, Arena J, Rha E, Vranis P, Hitt D, Marsh-Armstrong N, Koliatsos VE. Evidence for accelerated tauopathy in the retina of transgenic P301S tau mice exposed to repetitive mild traumatic brain injury. Exp Neurol 2015; 273:168-76. [DOI: 10.1016/j.expneurol.2015.08.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 07/01/2015] [Accepted: 08/18/2015] [Indexed: 12/14/2022]
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78
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Tau Hyperphosphorylation and Oxidative Stress, a Critical Vicious Circle in Neurodegenerative Tauopathies? OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:151979. [PMID: 26576216 PMCID: PMC4630413 DOI: 10.1155/2015/151979] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/08/2015] [Indexed: 12/14/2022]
Abstract
Hyperphosphorylation and aggregation of the microtubule-associated protein tau in brain, are pathological hallmarks of a large family of neurodegenerative disorders, named tauopathies, which include Alzheimer's disease. It has been shown that increased phosphorylation of tau destabilizes tau-microtubule interactions, leading to microtubule instability, transport defects along microtubules, and ultimately neuronal death. However, although mutations of the MAPT gene have been detected in familial early-onset tauopathies, causative events in the more frequent sporadic late-onset forms and relationships between tau hyperphosphorylation and neurodegeneration remain largely elusive. Oxidative stress is a further pathological hallmark of tauopathies, but its precise role in the disease process is poorly understood. Another open question is the source of reactive oxygen species, which induce oxidative stress in brain neurons. Mitochondria have been classically viewed as a major source for oxidative stress, but microglial cells were recently identified as reactive oxygen species producers in tauopathies. Here we review the complex relationships between tau pathology and oxidative stress, placing emphasis on (i) tau protein function, (ii) origin and consequences of reactive oxygen species production, and (iii) links between tau phosphorylation and oxidative stress. Further, we go on to discuss the hypothesis that tau hyperphosphorylation and oxidative stress are two key components of a vicious circle, crucial in neurodegenerative tauopathies.
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79
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Inducible Expression of a Truncated Form of Tau in Oligodendrocytes Elicits Gait Abnormalities and a Decrease in Myelin: Implications for Selective CNS Degenerative Diseases. Neurochem Res 2015; 40:2188-99. [DOI: 10.1007/s11064-015-1707-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 08/14/2015] [Accepted: 08/19/2015] [Indexed: 12/25/2022]
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80
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Im SY, Kim YE, Kim YJ. Genetics of Progressive Supranuclear Palsy. J Mov Disord 2015; 8:122-9. [PMID: 26413239 PMCID: PMC4572662 DOI: 10.14802/jmd.15033] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 08/21/2015] [Accepted: 08/24/2015] [Indexed: 12/21/2022] Open
Abstract
Progressive supranuclear palsy (PSP) is a neurodegenerative syndrome that is clinically characterized by progressive postural instability, supranuclear gaze palsy, parkinsonism and cognitive decline. Pathologically, diagnosis of PSP is based on characteristic features, such as neurofibrillary tangles, neutrophil threads, tau-positive astrocytes and their processes in basal ganglia and brainstem, and the accumulation of 4 repeat tau protein. PSP is generally recognized as a sporadic disorder; however, understanding of genetic background of PSP has been expanding rapidly. Here we review relevant publications to outline the genetics of PSP. Although only small number of familial PSP cases have been reported, the recognition of familial PSP has been increasing. In some familial cases of clinically probable PSP, PSP pathologies were confirmed based on NINDS neuropathological diagnostic criteria. Several mutations in MAPT, the gene that causes a form of familial frontotemporal lobar degeneration with tauopathy, have been identified in both sporadic and familial PSP cases. The H1 haplotype of MAPT is a risk haplotype for PSP, and within H1, a sub-haplotype (H1c) is associated with PSP. A recent genome-wide association study on autopsyproven PSP revealed additional PSP risk alleles in STX6 and EIF2AK3. Several heredodegenerative parkinsonian disorders are referred to as PSP-look-alikes because their clinical phenotype, but not their pathology, mimics PSP. Due to the fast development of genomics and bioinformatics, more genetic factors related to PSP are expected to be discovered. Undoubtedly, these studies will provide a better understanding of the pathogenesis of PSP and clues for developing therapeutic strategies.
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Affiliation(s)
- Sun Young Im
- Department of Neurology, Hallym University College of Medicine, Anyang, Korea
| | - Young Eun Kim
- Department of Neurology, Hallym University College of Medicine, Anyang, Korea
| | - Yun Joong Kim
- Department of Neurology, Hallym University College of Medicine, Anyang, Korea ; ILSONG Institute of Life Science, Hallym University, Anyang, Korea ; Hallym Institute of Translational Genomics & Bioinformatics, Anyang, Korea
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81
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Gentier RJ, van Leeuwen FW. Misframed ubiquitin and impaired protein quality control: an early event in Alzheimer's disease. Front Mol Neurosci 2015; 8:47. [PMID: 26388726 PMCID: PMC4557111 DOI: 10.3389/fnmol.2015.00047] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/18/2015] [Indexed: 12/21/2022] Open
Abstract
Amyloid β (Aβ) plaque formation is a prominent cellular hallmark of Alzheimer's disease (AD). To date, immunization trials in AD patients have not been effective in terms of curing or ameliorating dementia. In addition, γ-secretase inhibitor strategies await clinical improvements in AD. These approaches were based upon the idea that autosomal dominant mutations in amyloid precursor protein (APP) and Presenilin 1 (PS1) genes are predictive for treatment of all AD patients. However most AD patients are of the sporadic form which partly explains the failures to treat this multifactorial disease. The major risk factor for developing sporadic AD (SAD) is aging whereas the Apolipoprotein E polymorphism (ε4 variant) is the most prominent genetic risk factor. Other medium-risk factors such as triggering receptor expressed on myeloid cells 2 (TREM2) and nine low risk factors from Genome Wide Association Studies (GWAS) were associated with AD. Recently, pooled GWAS studies identified protein ubiquitination as one of the key modulators of AD. In addition, a brain site specific strategy was used to compare the proteomes of AD patients by an Ingenuity Pathway Analysis. This strategy revealed numerous proteins that strongly interact with ubiquitin (UBB) signaling, and pointing to a dysfunctional ubiquitin proteasome system (UPS) as a causal factor in AD. We reported that DNA-RNA sequence differences in several genes including ubiquitin do occur in AD, the resulting misframed protein of which accumulates in the neurofibrillary tangles (NFTs). This suggests again a functional link between neurodegeneration of the AD type and loss of protein quality control by the UPS. Progress in this field is discussed and modulating the activity of the UPS opens an attractive avenue of research towards slowing down the development of AD and ameliorating its effects by discovering prime targets for AD therapeutics.
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Affiliation(s)
- Romina J. Gentier
- Department of Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht UniversityMaastricht, Netherlands
| | - Fred W. van Leeuwen
- Department of Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht UniversityMaastricht, Netherlands
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82
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Caillet-Boudin ML, Buée L, Sergeant N, Lefebvre B. Regulation of human MAPT gene expression. Mol Neurodegener 2015; 10:28. [PMID: 26170022 PMCID: PMC4499907 DOI: 10.1186/s13024-015-0025-8] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 06/30/2015] [Indexed: 12/12/2022] Open
Abstract
The number of known pathologies involving deregulated Tau expression/metabolism is increasing. Indeed, in addition to tauopathies, which comprise approximately 30 diseases characterized by neuronal aggregation of hyperphosphorylated Tau in brain neurons, this protein has also been associated with various other pathologies such as cancer, inclusion body myositis, and microdeletion/microduplication syndromes, suggesting its possible function in peripheral tissues. In addition to Tau aggregation, Tau deregulation can occur at the expression and/or splicing levels, as has been clearly demonstrated in some of these pathologies. Here, we aim to review current knowledge regarding the regulation of human MAPT gene expression at the DNA and RNA levels to provide a better understanding of its possible deregulation. Several aspects, including repeated motifs, CpG island/methylation, and haplotypes at the DNA level, as well as the key regions involved in mRNA expression and stability and the splicing patterns of different mRNA isoforms at the RNA level, will be discussed.
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Affiliation(s)
| | - Luc Buée
- Univ. Lille, UMR-S 1172, Inserm, CHU, 59000, Lille, France
| | | | - Bruno Lefebvre
- Univ. Lille, UMR-S 1172, Inserm, CHU, 59000, Lille, France
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83
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Distinct Neurodegenerative Changes in an Induced Pluripotent Stem Cell Model of Frontotemporal Dementia Linked to Mutant TAU Protein. Stem Cell Reports 2015; 5:83-96. [PMID: 26143746 PMCID: PMC4618448 DOI: 10.1016/j.stemcr.2015.06.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Revised: 06/08/2015] [Accepted: 06/08/2015] [Indexed: 01/06/2023] Open
Abstract
Frontotemporal dementia (FTD) is a frequent form of early-onset dementia and can be caused by mutations in MAPT encoding the microtubule-associated protein TAU. Because of limited availability of neural cells from patients' brains, the underlying mechanisms of neurodegeneration in FTD are poorly understood. Here, we derived induced pluripotent stem cells (iPSCs) from individuals with FTD-associated MAPT mutations and differentiated them into mature neurons. Patient iPSC-derived neurons demonstrated pronounced TAU pathology with increased fragmentation and phospho-TAU immunoreactivity, decreased neurite extension, and increased but reversible oxidative stress response to inhibition of mitochondrial respiration. Furthermore, FTD neurons showed an activation of the unfolded protein response, and a transcriptome analysis demonstrated distinct, disease-associated gene expression profiles. These findings indicate distinct neurodegenerative changes in FTD caused by mutant TAU and highlight the unique opportunity to use neurons differentiated from patient-specific iPSCs to identify potential targets for drug screening purposes and therapeutic intervention.
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84
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Jeffrey M, Piccardo P, Ritchie DL, Ironside JW, Green AJE, McGovern G. A Naturally Occurring Bovine Tauopathy Is Geographically Widespread in the UK. PLoS One 2015; 10:e0129499. [PMID: 26091261 PMCID: PMC4474601 DOI: 10.1371/journal.pone.0129499] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 05/08/2015] [Indexed: 01/09/2023] Open
Abstract
Many human neurodegenerative diseases are associated with hyperphosphorylation and widespread intra-neuronal and glial associated aggregation of the microtubule associated protein tau. In contrast, animal tauopathies are not reported with only senescent animals showing inconspicuous tau labelling of fine processes albeit significant tau aggregation may occur in some experimental animal disease. Since 1986, an idiopathic neurological condition of adult cattle has been recognised in the UK as a sub-set of cattle slaughtered as suspect bovine spongiform encephalopathy cases. This disorder is characterised by brainstem neuronal chromatolysis and degeneration with variable hippocampal sclerosis and spongiform change. Selected cases of idiopathic brainstem neuronal chromatolysis (IBNC) were identified from archive material and characterised using antibodies specific to several tau hyperphosphorylation sites or different isoforms of the tau microtubule binding region. Labelling was also carried out for alpha synuclein, ubiquitin, TDP43, Aβ 1-42, Aβ 1-40. Widespread tau labelling was identified in all IBNC brains examined and with each of seven tau antibodies recognising different hyperphosphorylated sites. Labelling with each antibody was associated with dendrites, neuronal perikarya and glia. Thus IBNC is a sporadic, progressive neurological disease predominantly affecting aged cattle that occurs throughout the UK and is associated with hyperphosphorylation of tau, a rare example of a naturally-occurring tauopathy in a non-primate species. Secondary accumulation of alpha synuclein and ubiquitin was also present. The neuropathology does not precisely correspond with any human tauopathy. The cause of IBNC remains undetermined but environmental factors and exposure to agrochemicals needs to be considered in future aetiological investigations.
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Affiliation(s)
- Martin Jeffrey
- Animal and Plant Health Agency, Lasswade Veterinary Laboratory, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, Scotland
| | - Pedro Piccardo
- Laboratory of Bacterial and TSE-agents, Food and Drug Administration, Rockville, Maryland, United States of America
| | - Diane L. Ritchie
- National CJD Research & Surveillance Unit, Centre for Clinical Brain Sciences, School of Clinical Sciences, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, United Kingdom
| | - James W. Ironside
- National CJD Research & Surveillance Unit, Centre for Clinical Brain Sciences, School of Clinical Sciences, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, United Kingdom
| | - Alison J. E. Green
- National CJD Research & Surveillance Unit, Centre for Clinical Brain Sciences, School of Clinical Sciences, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, United Kingdom
| | - Gillian McGovern
- Animal and Plant Health Agency, Lasswade Veterinary Laboratory, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, Scotland
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85
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Basiri K, Ansari B, Meamar R. Frontotemporal dementia parkinsonism: Clinical findings in a large Iranian family. Adv Biomed Res 2015; 4:37. [PMID: 25789263 PMCID: PMC4358030 DOI: 10.4103/2277-9175.151242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 09/01/2014] [Indexed: 11/04/2022] Open
Abstract
Frontotemporal dementia (FTD) is a group of neurodegenerative disorders characterized by atrophy of the frontal and temporal lobes. Clinical features suggestive of FTD include pre-senile onset before the age of 65, behavioral changes, social and interpersonal disinhibition, fluent and nonfluent aphasia, and loss of insight. FTD and parkinsonism linked to chromosome 17 (FTDP-17) was defined during the International Consensus Conference in Ann Arbor, Michigan in 1996. FTDP-17 is an autosomally dominant inherited condition. Most genotypic alterations do not correlate with clinical phenotypes. However, mutations affecting exon 10 splicing are associated with parkinsonism. In the present study, a male case with FTDP who presented with insidious onset of speech difficulty at a young age that was associated with signs of parkinsonism and a positive family history of FTD with MAPT gene mutation at exon 13 has been reported.
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Affiliation(s)
- Keivan Basiri
- Department of Neurology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Behnaz Ansari
- Department of Neurology, Isfahan University of Medical Sciences, Isfahan, Iran
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86
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Ghetti B, Oblak AL, Boeve BF, Johnson KA, Dickerson BC, Goedert M. Invited review: Frontotemporal dementia caused by microtubule-associated protein tau gene (MAPT) mutations: a chameleon for neuropathology and neuroimaging. Neuropathol Appl Neurobiol 2015; 41:24-46. [PMID: 25556536 PMCID: PMC4329416 DOI: 10.1111/nan.12213] [Citation(s) in RCA: 310] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 12/29/2014] [Indexed: 12/12/2022]
Abstract
Hereditary frontotemporal dementia associated with mutations in the microtubule-associated protein tau gene (MAPT) is a protean disorder. Three neuropathologic subtypes can be recognized, based on the presence of inclusions made of tau isoforms with three and four repeats, predominantly three repeats and mostly four repeats. This is relevant for establishing a correlation between structural magnetic resonance imaging and positron emission tomography using tracers specific for aggregated tau. Longitudinal studies will be essential to determine the evolution of anatomical alterations from the asymptomatic stage to the various phases of disease following the onset of symptoms.
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Affiliation(s)
- B Ghetti
- Department of Pathology and Laboratory Medicine, Indiana University School of MedicineIndianapolis, USA
| | - A L Oblak
- Department of Pathology and Laboratory Medicine, Indiana University School of MedicineIndianapolis, USA
| | - B F Boeve
- Department of Neurology, Mayo ClinicRochester, USA
| | - K A Johnson
- Department of Radiology, Massachusetts General Hospital and Harvard Medical SchoolBoston, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical SchoolBoston, USA
| | - B C Dickerson
- Department of Neurology, Massachusetts General Hospital and Harvard Medical SchoolBoston, USA
| | - M Goedert
- Medical Research Council, Laboratory of Molecular BiologyCambridge, UK
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87
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The calcium-binding protein EFhd2 modulates synapse formation in vitro and is linked to human dementia. J Neuropathol Exp Neurol 2015; 73:1166-82. [PMID: 25383639 PMCID: PMC4238966 DOI: 10.1097/nen.0000000000000138] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
EFhd2 is a calcium-binding adaptor protein that has been found to be associated with pathologically aggregated tau in the brain in Alzheimer disease and in a mouse model of frontotemporal dementia. EFhd2 has cell type-specific functions, including the modulation of intracellular calcium responses, actin dynamics, and microtubule transport. Here we report that EFhd2 protein and mRNA levels are reduced in human frontal cortex tissue affected by different types of dementia with and without tau pathology. We show that EFhd2 is mainly a neuronal protein in the brain and is abundant in the forebrain. Using short hairpin RNA-mediated knockdown of EFhd2 expression in cultured cortical neurons, we demonstrate that loss of EFhd2 affects the number of synapses developed in vitro whereas it does not alter neurite outgrowth per se. Our data suggest that EFhd2 is involved in the control of synapse development and maintenance through means other than affecting neurite development. The changes in expression levels observed in human dementias might, therefore, play a significant role in disease onset and progression of dementia, which is characterized by the loss of synapses.
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88
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Gramaglia C, Cantello R, Terazzi E, Carecchio M, D'Alfonso S, Chieppa N, Ressico F, Rizza MC, Zeppegno P. Early onset frontotemporal dementia with psychiatric presentation due to the C9ORF72 hexanucleotide repeat expansion: a case report. BMC Neurol 2014; 14:228. [PMID: 25433797 PMCID: PMC4264324 DOI: 10.1186/s12883-014-0228-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 11/18/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Frontotemporal dementia (FTD) may present with psychiatric symptoms, usually together with neurological ones and in cases with a family history of dementia. We describe the case of an FTD behavioural variant with a psychiatric presentation and a normal neurological examination, due to a C9Orf72 gene mutation. CASE PRESENTATION The patient was a 57 years-old Caucasian woman with a recent onset of bizarre behaviours and mystic delusions. She had a negative clinical history for previous psychiatric disorders and treatments and this was her first admission to a Psychiatry Ward. A careful assessment was performed including, beyond psychiatric evaluation, the following: blood sampling, neurological examination (including electroencephalogram, electroencephalogram with zygomatic electrodes, Positron Emission Tomography, Cerebrospinal Fluid Analysis), carotid artery Doppler ultrasound, brain Magnetic Resonance Imaging - angio Magnetic Resonance Imaging. Blood sampling for the genetic assessment of mutations associated to primary dementias was performed as well: the genes investigated were FUS, C9Orf72, PSEN-1, PSEN-2. CONCLUSIONS Serological tests were negative, neurological examination was normal, instrumental examinations showed theta waves in the posterior temporal areas bilaterally and frontotemporal cortical atrophy bilaterally. The genetic assessment of mutations associated revealed she carried a GGGGCC hexanucleotide repeat expansion (at least 80 repeats) in C9Orf72 intron 1. Patients carrying the C9Orf72 mutation are likely to receive a psychiatric diagnosis (mainly mood disorder or schizophrenia) prior to correct diagnosis; this may be particularly problematic for those patients with no neurological signs to orientate diagnosis. Understanding the manner in which such FTD variant may present as a psychiatric syndrome, with a negative neurological examination, is essential to provide the best treatment for patients, as soon as possible, especially when the behavioural anomalies interfere with their care.
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89
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Lost after translation: missorting of Tau protein and consequences for Alzheimer disease. Trends Neurosci 2014; 37:721-32. [PMID: 25223701 DOI: 10.1016/j.tins.2014.08.004] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 08/08/2014] [Accepted: 08/12/2014] [Indexed: 12/19/2022]
Abstract
Tau is a microtubule-associated-protein that is sorted into neuronal axons in physiological conditions. In Alzheimer disease (AD) and other tauopathies, Tau sorting mechanisms fail and Tau becomes missorted into the somatodendritic compartment. In AD, aberrant amyloid-β (Aβ) production might trigger Tau missorting. The physiological axonal sorting of Tau depends on the developmental stage of the neuron, the phosphorylation state of Tau and the microtubule cytoskeleton. Disease-associated missorting of Tau is connected to increased phosphorylation and aggregation of Tau, and impaired microtubule interactions. Disease-causing mechanisms involve impaired transport, aberrant kinase activation, non-physiological interactions of Tau, and prion-like spreading. In this review we focus on the physiological and pathological (mis)sorting of Tau, the underlying mechanisms, and effects in disease.
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90
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Jellinger KA, Attems J. Challenges of multimorbidity of the aging brain: a critical update. J Neural Transm (Vienna) 2014; 122:505-21. [DOI: 10.1007/s00702-014-1288-x] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 07/24/2014] [Indexed: 12/11/2022]
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91
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Scholz T, Mandelkow E. Transport and diffusion of Tau protein in neurons. Cell Mol Life Sci 2014; 71:3139-50. [PMID: 24687422 PMCID: PMC11113808 DOI: 10.1007/s00018-014-1610-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 02/20/2014] [Accepted: 03/13/2014] [Indexed: 12/11/2022]
Abstract
In highly polarized and elongated cells such as neurons, Tau protein must enter and move down the axon to fulfill its biological task of stabilizing axonal microtubules. Therefore, cellular systems for distributing Tau molecules are needed. This review discusses different mechanisms that have been proposed to contribute to the dispersion of Tau molecules in neurons. They include (1) directed transport along microtubules as cargo of tubulin complexes and/or motor proteins, (2) diffusion, either through the cytosolic space or along microtubules, and (3) mRNA-based mechanisms such as transport of Tau mRNA into axons and local translation. Diffusion along the microtubule lattice or through the cytosol appear to be the major mechanisms for axonal distribution of Tau protein in the short-to-intermediate range over distances of up to a millimetre. The high diffusion coefficients ensure that Tau can distribute evenly throughout the axonal volume as well as along microtubules. Motor protein-dependent transport of Tau dominates over longer distances and time scales. At low near-physiological levels, Tau is co-transported along with short microtubules from cell bodies into axons by cytoplasmic dynein and kinesin family members at rates of slow axonal transport.
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Affiliation(s)
- Tim Scholz
- Institute for Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625, Hannover, Germany,
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92
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Regulation of autophagy by mTOR-dependent and mTOR-independent pathways: autophagy dysfunction in neurodegenerative diseases and therapeutic application of autophagy enhancers. Biochem Soc Trans 2014; 41:1103-30. [PMID: 24059496 DOI: 10.1042/bst20130134] [Citation(s) in RCA: 269] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autophagy is an intracellular degradation pathway essential for cellular and energy homoeostasis. It functions in the clearance of misfolded proteins and damaged organelles, as well as recycling of cytosolic components during starvation to compensate for nutrient deprivation. This process is regulated by mTOR (mammalian target of rapamycin)-dependent and mTOR-independent pathways that are amenable to chemical perturbations. Several small molecules modulating autophagy have been identified that have potential therapeutic application in diverse human diseases, including neurodegeneration. Neurodegeneration-associated aggregation-prone proteins are predominantly degraded by autophagy and therefore stimulating this process with chemical inducers is beneficial in a wide range of transgenic disease models. Emerging evidence indicates that compromised autophagy contributes to the aetiology of various neurodegenerative diseases related to protein conformational disorders by causing the accumulation of mutant proteins and cellular toxicity. Combining the knowledge of autophagy dysfunction and the mechanism of drug action may thus be rational for designing targeted therapy. The present review describes the cellular signalling pathways regulating mammalian autophagy and highlights the potential therapeutic application of autophagy inducers in neurodegenerative disorders.
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93
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Majid T, Ali YO, Venkitaramani DV, Jang MK, Lu HC, Pautler RG. In vivo axonal transport deficits in a mouse model of fronto-temporal dementia. NEUROIMAGE-CLINICAL 2014; 4:711-7. [PMID: 24936422 PMCID: PMC4053640 DOI: 10.1016/j.nicl.2014.02.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Revised: 02/12/2014] [Accepted: 02/14/2014] [Indexed: 11/16/2022]
Abstract
Background Axonal transport is vital for neurons and deficits in this process have been previously reported in a few mouse models of Alzheimer's disease prior to the appearance of plaques and tangles. However, it remains to be determined whether axonal transport is defective prior to the onset of neurodegeneration. The rTg4510 mouse, a fronto-temporal dementia and parkinsonism-17 (FTDP-17) tauopathy model, over-express tau-P301L mutation found in familial forms of FTDP-17, in the forebrain driven by the calcium–calmodulin kinase II promoter. This mouse model exhibits tau pathology, neurodegeneration in the forebrain, and associated behavioral deficits beginning at 4–5 months of age. Animal model rTg4510 transgenic mice were used in these studies. Mice were given 2 μL of MnCl2 in each nostril 1 h prior to Magnetic Resonance Imaging (MRI). Following MnCl2 nasal lavage, mice were imaged using Manganese enhanced Magnetic Resonance Imaging (MEMRI) Protocol with TE = 8.5 ms, TR = 504 ms, FOV = 3.0 cm, matrix size = 128 × 128 × 128, number of cycles = 15 with each cycle taking approximately 2 min, 9 s, and 24 ms using Paravision software (BrukerBioSpin, Billerica, MA). During imaging, body temperature was maintained at 37.0 °C using an animal heating system (SA Instruments, Stony Brook, NY). Data analysis Resulting images were analyzed using Paravision software. Regions of interest (ROI) within the olfactory neuronal layer (ONL) and the water phantom consisting of one pixel (ONL) and 9 pixels (water) were selected and copied across each of the 15 cycles. Signal intensities (SI) of ONL and water phantom ROIs were measured. SI values obtained for ONL were then normalized the water phantom SI values. The correlation between normalized signal intensity in the ONL and time were assessed using Prism (GraphPad Software, San Diego, CA). Results Using the MEMRI technique on 1.5, 3, 5, and 10-month old rTg4510 mice and littermate controls, we found significant axonal transport deficits present in the rTg4510 mice beginning at 3 months of age in an age-dependent manner. Using linear regression analysis, we measured rates of axonal transport at 1.5, 3, 5, and 10 months of age in rTg4510 and WT mice. Axonal transport rates were observed in rTg4510 mice at 48% of WT levels at 3 months, 40% of WT levels at 5 months, and 30% of WT levels at 10 months of age. In order to determine the point at which tau appears in the cortex, we probed for phosphorylated tau levels, and found that pSer262 is present at 3 months of age, not earlier at 1.5 months of age, but observed no pathological tau species until 6 months of age, months after the onset of the transport deficits. In addition, we saw localization of tau in the ONL at 6 months of age. Discussion In our study, we identified the presence of age-dependent axonal transport deficits beginning at 3 months of age in rTg4510 mice. We correlated these deficits at 3 months to the presence of hyperphosphorylated tau in the brain and the presence within the olfactory epithelium. We observed tau pathology not only in the soma of these neurons but also within the axons and processes of these neurons. Our characterization of axonal transport in this tauopathy model provides a functional time point that can be used for future therapeutic interventions. We used MEMRI to define axonal transport rate changes in the rTg4510 mouse. We observed significant hyperphosphorylated tau starting at 3 months of age. We found an age-dependent decline in axonal transport rates. Declines in axonal transport correlated with increases in hyperphosphorylated tau.
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Affiliation(s)
- Tabassum Majid
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, USA ; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, USA
| | - Yousuf O Ali
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA ; The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA
| | - Deepa V Venkitaramani
- Institute for Applied Cancer Science, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Ming-Kuei Jang
- Institute for Applied Cancer Science, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA
| | - Hui-Chen Lu
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA ; The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, USA ; Developmental Biology Program, Baylor College of Medicine, Houston, TX, USA ; Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Robia G Pautler
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, USA ; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, USA ; Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
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94
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Hernández I, Mauleón A, Rosense-Roca M, Alegret M, Vinyes G, Espinosa A, Sotolongo-Grau O, Becker JT, Valero S, Tarraga L, López OL, Ruiz A, Boada M. Identification of misdiagnosed fronto-temporal dementia using APOE genotype and phenotype-genotype correlation analyses. Curr Alzheimer Res 2014; 11:182-91. [PMID: 24359501 PMCID: PMC4079551 DOI: 10.2174/1567205010666131212120443] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 11/04/2013] [Accepted: 11/08/2013] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Postmortem and genetic studies of clinically diagnosed Frontotemporal dementia (FTD) patients suggest that a number of clinically diagnosed FTD patients are actually "frontal variants" of Alzheimer's disease (fvAD). The purpose of this study was to evaluate this hypothesis by combining neuropathological data, genetic association studies of APOE, phenotype-APOE genotype correlations and discriminant analysis techniques. METHODS Neuropathological information on 24 FTD cases, genetic association studies of APOE (168 FTD, 3083 controls and 2528 AD), phenotypegenotype correlations and discriminant techniques (LDA, logistic regression and decision trees) were combined to identify fvAD patients within a clinical FTD series. RESULTS Four of 24 FTLD patients (16.6%) met criteria for definite AD. By comparing allele and genotype frequencies of APOE in controls, FTD and AD groups and by applying the Hardy- Weinberg equilibrium law (HWE), we inferred a consistent (17.2%) degree of AD contamination in clinical FTD. A penetrance analysis for APOE ε4 genotype in the FTD series identified 14 features for discrimination analysis. These features were compared between clinical AD (n=332) and clinical FTD series (n=168) and classifiers were constructed usinglinear discriminant analysis logistic regression or decision tree techniques. The classifier had 92.8% sensitivity to FTD and 93.4% sensitivity to AD relative to neuropathology (global AUC=0.939, p<<0.001). We identified 30 potential fvAD cases (17.85%) in the clinical FTD sample. CONCLUSION The APOE locus association in clinical FTD might be entirely explained by the existence of "hidden" fvAD cases within an FTD sample. The degree of fvAD contamination can be inferred from APOE genotypes.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Mercè Boada
- Fundacio ACE, Marques de Sentmenat, 57, 08029 Barcelona (Spain).
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95
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Iovino M, Pfisterer U, Holton JL, Lashley T, Swingler RJ, Calo L, Treacy R, Revesz T, Parmar M, Goedert M, Muqit MMK, Spillantini MG. The novel MAPT mutation K298E: mechanisms of mutant tau toxicity, brain pathology and tau expression in induced fibroblast-derived neurons. Acta Neuropathol 2014; 127:283-95. [PMID: 24292008 PMCID: PMC3895181 DOI: 10.1007/s00401-013-1219-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 11/15/2013] [Indexed: 11/28/2022]
Abstract
Frontotemporal lobar degeneration (FTLD) consists of a group of neurodegenerative diseases characterized by behavioural and executive impairment, language disorders and motor dysfunction. About 20-30% of cases are inherited in a dominant manner. Mutations in the microtubule-associated protein tau gene (MAPT) cause frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17T). Here we report a novel MAPT mutation (K298E) in exon 10 in a patient with FTDP-17T. Neuropathological studies of post-mortem brain showed widespread neuronal loss and gliosis and abundant deposition of hyperphosphorylated tau in neurons and glia. Molecular studies demonstrated that the K298E mutation affects both protein function and alternative mRNA splicing. Fibroblasts from a skin biopsy of the proband taken at post-mortem were directly induced into neurons (iNs) and expressed both 3-repeat and 4-repeat tau isoforms. As well as contributing new knowledge on MAPT mutations in FTDP-17T, this is the first example of the successful generation of iNs from skin cells retrieved post-mortem.
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Affiliation(s)
- Mariangela Iovino
- Cambridge Centre for Brain Repair, University of Cambridge, Cambridge, UK
| | - Ulrich Pfisterer
- Department of Experimental Medical Science and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Janice L. Holton
- Queen Square Brain Bank for Neurological Disorders, Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
| | - Tammaryn Lashley
- Queen Square Brain Bank for Neurological Disorders, Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
| | - Robert J. Swingler
- Department of Neurology, Ninewells Hospital, College of Medicine, Nursing and Dentistry, University of Dundee, Dundee, UK
| | - Laura Calo
- Cambridge Centre for Brain Repair, University of Cambridge, Cambridge, UK
| | - Rebecca Treacy
- Genetics Laboratories, Molecular Genetics, Addenbrooke’s Treatment Centre, Addenbrooke’s Hospital, Cambridge, UK
| | - Tamas Revesz
- Queen Square Brain Bank for Neurological Disorders, Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
| | - Malin Parmar
- Department of Experimental Medical Science and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Michel Goedert
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, UK
| | - Miratul M. K. Muqit
- Department of Neurology, Ninewells Hospital, College of Medicine, Nursing and Dentistry, University of Dundee, Dundee, UK
- Medical Research Council Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK
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96
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Affiliation(s)
- Karen Chiang
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093; ,
| | - Edward H. Koo
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093; ,
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Tau pathology is present in vivo and develops in vitro in sensory neurons from human P301S tau transgenic mice: a system for screening drugs against tauopathies. J Neurosci 2014; 33:18175-89. [PMID: 24227726 DOI: 10.1523/jneurosci.4933-12.2013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Intracellular tau aggregates are the neuropathological hallmark of several neurodegenerative diseases, including Alzheimer's disease, progressive supranuclear palsy, and cases of frontotemporal dementia, but the link between these aggregates and neurodegeneration remains unclear. Neuronal models recapitulating the main features of tau pathology are necessary to investigate the molecular mechanisms of tau malfunction, but current models show little and inconsistent spontaneous tau aggregation. We show that dorsal root ganglion (DRG) neurons in transgenic mice expressing human P301S tau (P301S-htau) develop tau pathology similar to that found in brain and spinal cord and a significant reduction in mechanosensation occurs before detectable fibrillar tau formation. DRG neuronal cultures established from adult P301S-htau mice at different ages retained the pattern of aberrant tau found in vivo. Moreover, htau became progressively hyperphosphorylated over 2 months in vitro beginning with nonsymptomatic neurons, while hyperphosphorylated P301S-htau-positive neurons from 5-month-old mice cultured for 2 months died preferentially. P301S-htau-positive neurons grew aberrant axons, including spheroids, typically found in human tauopathies. Neurons cultured at advanced stages of tau pathology showed a 60% decrease in the fraction of moving mitochondria. SEG28019, a novel O-GlcNAcase inhibitor, reduced steady-state pSer396/pSer404 phosphorylation over 7 weeks in a significant proportion of DRG neurons showing for the first time the possible beneficial effect of prolonged dosing of O-GlcNAcase inhibitor in vitro. Our system is unique in that fibrillar tau forms without external manipulation and provides an important new tool for understanding the mechanisms of tau dysfunction and for screening of compounds for treatment of tauopathies.
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98
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Inclusion body formation, macroautophagy, and the role of HDAC6 in neurodegeneration. Acta Neuropathol 2013; 126:793-807. [PMID: 23912309 DOI: 10.1007/s00401-013-1158-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 07/23/2013] [Indexed: 12/25/2022]
Abstract
The failure to clear misfolded or aggregated proteins from the cytoplasm of nerve cells and glia is a common pathogenic event in a variety of neurodegenerative disorders. This might be causally related to defects in the major proteolytic systems, i.e., the ubiquitin-proteasomal system and the autophagic pathway. Large protein aggregates and defective organelles are excluded from the proteasome. They can be degraded only by macroautophagy, which is a highly selective process. It requires p62 to act as a bridge connecting ubiquitinated protein aggregates and autophagosomes, and the tubulin deacetylase histone deacetylase 6 (HDAC6). HDAC6 has recently been identified as a constituent in Lewy bodies of Parkinson disease and glial cytoplasmic inclusions of multiple system atrophy. It is considered a sensor of proteasomal inhibition and a cellular stress surveillance factor, and plays a central role in autophagy by controlling the fusion process of autophagosomes with lysosomes. Upon proteasomal inhibition, HDAC6 is relocated and recruited to polyubiquitin-positive aggresomes. Tubulin acetylation is a major consequence of HDAC6 inhibition, and HDAC6 inhibition restores microtubule (MT)-dependent transport mechanisms in neurons. This suggests the involvement of HDAC6 in neurodegenerative diseases. Furthermore, the protein tau seems to be a substrate for HDAC6. Tau acetylation impairs MT assembly and promotes tau fibrillization in vitro. It has been suggested that acetylation and phosphorylation of tau at multiples sites may act synergistically in the pathogenesis of tau fibrillization. In this review, we will survey the process of aggresome formation, macroautophagy and the role of autophagosomal proteins and HDAC6 in inclusion body formation.
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99
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A novel MAPT mutation, G55R, in a frontotemporal dementia patient leads to altered Tau function. PLoS One 2013; 8:e76409. [PMID: 24086739 PMCID: PMC3785453 DOI: 10.1371/journal.pone.0076409] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 08/26/2013] [Indexed: 11/19/2022] Open
Abstract
Over two dozen mutations in the gene encoding the microtubule associated protein tau cause a variety of neurodegenerative dementias known as tauopathies, including frontotemporal dementia (FTD), PSP, CBD and Pick's disease. The vast majority of these mutations map to the C-terminal region of tau possessing microtubule assembly and microtubule dynamics regulatory activities as well as the ability to promote pathological tau aggregation. Here, we describe a novel and non-conservative tau mutation (G55R) mapping to an alternatively spliced exon encoding part of the N-terminal region of the protein in a patient with the behavioral variant of FTD. Although less well understood than the C-terminal region of tau, the N-terminal region can influence both MT mediated effects as well as tau aggregation. The mutation changes an uncharged glycine to a basic arginine in the midst of a highly conserved and very acidic region. In vitro, 4-repeat G55R tau nucleates microtubule assembly more effectively than wild-type 4-repeat tau; surprisingly, this effect is tau isoform specific and is not observed in a 3-repeat G55R tau versus 3-repeat wild-type tau comparison. In contrast, the G55R mutation has no effect upon the abilities of tau to regulate MT growing and shortening dynamics or to aggregate. Additionally, the mutation has no effect upon kinesin translocation in a microtubule gliding assay. Together, (i) we have identified a novel tau mutation mapping to a mutation deficient region of the protein in a bvFTD patient, and (ii) the G55R mutation affects the ability of tau to nucleate microtubule assembly in vitro in a 4-repeat tau isoform specific manner. This altered capability could markedly affect in vivo microtubule function and neuronal cell biology. We consider G55R to be a candidate mutation for bvFTD since additional criteria required to establish causality are not yet available for assessment.
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Mandelkow EM, Mandelkow E. Biochemistry and cell biology of tau protein in neurofibrillary degeneration. Cold Spring Harb Perspect Med 2013; 2:a006247. [PMID: 22762014 DOI: 10.1101/cshperspect.a006247] [Citation(s) in RCA: 526] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Tau represents the subunit protein of one of the major hallmarks of Alzheimer disease (AD), the neurofibrillary tangles, and is therefore of major interest as an indicator of disease mechanisms. Many of the unusual properties of Tau can be explained by its nature as a natively unfolded protein. Examples are the large number of structural conformations and biochemical modifications (phosphorylation, proteolysis, glycosylation, and others), the multitude of interaction partners (mainly microtubules, but also other cytoskeletal proteins, kinases, and phosphatases, motor proteins, chaperones, and membrane proteins). The pathological aggregation of Tau is counterintuitive, given its high solubility, but can be rationalized by short hydrophobic motifs forming β structures. The aggregation of Tau is toxic in cell and animal models, but can be reversed by suppressing expression or by aggregation inhibitors. This review summarizes some of the structural, biochemical, and cell biological properties of Tau and Tau fibers. Further aspects of Tau as a diagnostic marker and therapeutic target, its involvement in other Tau-based diseases, and its histopathology are covered by other chapters in this volume.
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Affiliation(s)
- Eva-Maria Mandelkow
- Max-Planck Unit for Structural Molecular Biology, c/o DESY, 22607 Hamburg, Germany; DZNE, German Center for Neurodegenerative Diseases, and CAESAR Research Center, 53175 Bonn, Germany.
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