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Roos P, Johannsen P, Lindquist SG, Brown JM, Waldemar G, Duno M, Nielsen TT, Budtz‐Jørgensen E, Gydesen S, Holm IE, Collinge J, Isaacs AM, Nielsen JE, Gade A, Stokholm J, Thusgaard T, Fisher EM, Englund E. Six generations of CHMP2B-mediated Frontotemporal Dementia: Clinical features, predictive testing, progression, and survival. Acta Neurol Scand 2022; 145:529-540. [PMID: 34997757 DOI: 10.1111/ane.13578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 11/04/2021] [Accepted: 11/07/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Chromosome 3-linked frontotemporal dementia (FTD-3) is caused by a c.532-1G > C mutation in the CHMP2B gene. It is extensively studied in a Danish family comprising one of the largest families with an autosomal dominantly inherited frontotemporal dementia (FTD). This retrospective cohort study utilizes demographics to identify risk factors for onset, progression, life expectancy, and death in CHMP2B-mediated FTD. The pedigree of 528 individuals in six generations is provided, and clinical descriptions are presented. Choices of genetic testing are evaluated. MATERIALS AND METHODS Demographic and lifestyle factors were assessed in survival analysis in all identified CHMP2B mutation carriers (44 clinically affected FTD-3 patients and 16 presymptomatic CHMP2B mutation carriers). Predictors of onset and progression included sex, parental disease course, education, and vascular risk factors. Life expectancy was established by matching CHMP2B mutation carriers with average life expectancies in Denmark. RESULTS Disease course was not correlated to parental disease course and seemed unmodified by lifestyle factors. Diagnosis was recognized at an earlier age in members with higher levels of education, probably reflecting an early dysexecutive syndrome, unmasked earlier in people with higher work-related requirements. Carriers of the CHMP2B mutation had a significant reduction in life expectancy of 13 years. Predictive genetic testing was chosen by 20% of at-risk family members. CONCLUSIONS CHMP2B-mediated FTD is substantiated as an autosomal dominantly inherited disease of complete penetrance. The clinical phenotype is a behavioral variant FTD. The disease course is unpredictable, and life expectancy is reduced. The findings may be applicable to other genetic FTD subtypes.
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Affiliation(s)
- Peter Roos
- Danish Dementia Research Centre Department of Neurology Rigshospitalet University of Copenhagen Denmark
| | - Peter Johannsen
- Danish Dementia Research Centre Department of Neurology Rigshospitalet University of Copenhagen Denmark
- Medical & Science Novo Nordisk A/S Søborg Denmark
| | - Suzanne G. Lindquist
- Danish Dementia Research Centre Department of Neurology Rigshospitalet University of Copenhagen Denmark
- Department of Clinical Genetics, Rigshospitalet University of Copenhagen Denmark
| | | | - Gunhild Waldemar
- Danish Dementia Research Centre Department of Neurology Rigshospitalet University of Copenhagen Denmark
| | - Morten Duno
- Department of Clinical Genetics, Rigshospitalet University of Copenhagen Denmark
| | - Troels T. Nielsen
- Danish Dementia Research Centre Department of Neurology Rigshospitalet University of Copenhagen Denmark
| | - Esben Budtz‐Jørgensen
- Section of Biostatistics Department of Public Health University of Copenhagen Denmark
| | | | - Ida E. Holm
- Department of Pathology Aalborg University Hospital Randers Denmark
| | - John Collinge
- MRC Prion Unit at UCL UCL Institute of Prion Diseases Courtauld Building London UK
| | - Adrian M. Isaacs
- Department of Neuromuscular Diseases UCL Institute of Neurology Queen Square London UK
- UK Dementia Research Institute at UCL UCL Institute of Neurology Queen Square London UK
| | - Jørgen E. Nielsen
- Danish Dementia Research Centre Department of Neurology Rigshospitalet University of Copenhagen Denmark
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Udayar V, Chen Y, Sidransky E, Jagasia R. Lysosomal dysfunction in neurodegeneration: emerging concepts and methods. Trends Neurosci 2022; 45:184-199. [PMID: 35034773 PMCID: PMC8854344 DOI: 10.1016/j.tins.2021.12.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 11/23/2021] [Accepted: 12/12/2021] [Indexed: 02/06/2023]
Abstract
The understanding of lysosomes has come a long way since the initial discovery of their role in degrading cellular waste. The lysosome is now recognized as a highly dynamic organelle positioned at the crossroads of cell signaling, transcription, and metabolism. Underscoring its importance is the observation that, in addition to rare monogenic lysosomal storage disorders, genes regulating lysosomal function are implicated in common sporadic neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). Developing therapies for these disorders is particularly challenging, largely due to gaps in knowledge of the underlying molecular and cellular processes. In this review, we discuss technological advances that have propelled deeper understanding of the lysosome in neurodegeneration, from elucidating the functions of lysosome-related disease risk variants at the level of the organelle, cell, and tissue, to the development of disease-specific biological models that recapitulate disease manifestations. Finally, we identify key questions to be addressed to successfully bridge the gap to the clinic.
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Affiliation(s)
- Vinod Udayar
- Roche Pharmaceutical Research and Early Development, Neuroscience and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Yu Chen
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ellen Sidransky
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Ravi Jagasia
- Roche Pharmaceutical Research and Early Development, Neuroscience and Rare Diseases Discovery & Translational Area, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland.
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Clayton EL, Bonnycastle K, Isaacs AM, Cousin MA, Schorge S. A novel synaptopathy-defective synaptic vesicle protein trafficking in the mutant CHMP2B mouse model of frontotemporal dementia. J Neurochem 2022; 160:412-425. [PMID: 34855215 DOI: 10.1111/jnc.15551] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 11/10/2021] [Accepted: 11/18/2021] [Indexed: 12/13/2022]
Abstract
Mutations in the ESCRT-III subunit CHMP2B cause frontotemporal dementia (FTD) and lead to impaired endolysosomal trafficking and lysosomal storage pathology in neurons. We investigated the effect of mutant CHMP2B on synaptic pathology, as ESCRT function was recently implicated in the degradation of synaptic vesicle (SV) proteins. We report here that expression of C-terminally truncated mutant CHMP2B results in a novel synaptopathy. This unique synaptic pathology is characterised by selective retention of presynaptic SV trafficking proteins in aged mutant CHMP2B transgenic mice, despite significant loss of postsynaptic proteins. Furthermore, ultrastructural analysis of primary cortical cultures from transgenic CHMP2B mice revealed a significant increase in the number of presynaptic endosomes, while neurons expressing mutant CHMP2B display defective SV recycling and alterations to functional SV pools. Therefore, we reveal how mutations in CHMP2B affect specific presynaptic proteins and SV recycling, identifying CHMP2B FTD as a novel synaptopathy. This novel synaptopathic mechanism of impaired SV physiology may be a key early event in multiple forms of FTD, since proteins that mediate the most common genetic forms of FTD all localise at the presynapse.
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Affiliation(s)
- Emma L Clayton
- Department of Pharmacology, UCL School of Pharmacy, London, UK
- Currently at UK Dementia Research Institute at King's College London, London, UK
| | - Katherine Bonnycastle
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, Scotland
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, Scotland
| | - Adrian M Isaacs
- UK Dementia Research Institute at UCL, London, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, Scotland
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, Scotland
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Chandrasekaran A, Dittlau KS, Corsi GI, Haukedal H, Doncheva NT, Ramakrishna S, Ambardar S, Salcedo C, Schmidt SI, Zhang Y, Cirera S, Pihl M, Schmid B, Nielsen TT, Nielsen JE, Kolko M, Kobolák J, Dinnyés A, Hyttel P, Palakodeti D, Gorodkin J, Muddashetty RS, Meyer M, Aldana BI, Freude KK. Astrocytic reactivity triggered by defective autophagy and metabolic failure causes neurotoxicity in frontotemporal dementia type 3. Stem Cell Reports 2021; 16:2736-2751. [PMID: 34678206 PMCID: PMC8581052 DOI: 10.1016/j.stemcr.2021.09.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 12/24/2022] Open
Abstract
Frontotemporal dementia type 3 (FTD3), caused by a point mutation in the charged multivesicular body protein 2B (CHMP2B), affects mitochondrial ultrastructure and the endolysosomal pathway in neurons. To dissect the astrocyte-specific impact of mutant CHMP2B expression, we generated astrocytes from human induced pluripotent stem cells (hiPSCs) and confirmed our findings in CHMP2B mutant mice. Our data provide mechanistic insights into how defective autophagy causes perturbed mitochondrial dynamics with impaired glycolysis, increased reactive oxygen species, and elongated mitochondrial morphology, indicating increased mitochondrial fusion in FTD3 astrocytes. This shift in astrocyte homeostasis triggers a reactive astrocyte phenotype and increased release of toxic cytokines, which accumulate in nuclear factor kappa b (NF-κB) pathway activation with increased production of CHF, LCN2, and C3 causing neurodegeneration. FTD3 iPSC-derived astrocytes display impaired autophagy Impaired autophagy affects mitochondria turnover, glucose hypometabolism and TCA cycle FTD3 astrocytes contribute to reactive gliosis by increased C3, LCN2, IL6, and IL8 Reactive astrocyte phenotypes are present in both in vitro and in vivo models
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Affiliation(s)
- Abinaya Chandrasekaran
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | - Katarina Stoklund Dittlau
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | - Giulia I Corsi
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark; Center for Non-coding RNA in Technology and Health, University of Copenhagen, Frederiksberg 1871, Denmark
| | - Henriette Haukedal
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | - Nadezhda T Doncheva
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark; Center for Non-coding RNA in Technology and Health, University of Copenhagen, Frederiksberg 1871, Denmark; Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen 2200, Denmark
| | - Sarayu Ramakrishna
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore 560065, India; The University of Trans-Disciplinary Health Sciences and Technology, Bangalore 560064, India
| | - Sheetal Ambardar
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore 560065, India; National Center for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, India
| | - Claudia Salcedo
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Sissel I Schmidt
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, 5000 Odense, Denmark
| | - Yu Zhang
- Department of Experimental Medical Science, Wallenberg Center for Molecular Medicine and Lund Stem Cell Center, Lund University, Lund 22184, Sweden
| | - Susanna Cirera
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | - Maria Pihl
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | | | - Troels Tolstrup Nielsen
- Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen 2100, Denmark
| | - Jørgen E Nielsen
- Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen 2100, Denmark
| | - Miriam Kolko
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark; Department of Ophthalmology, Copenhagen University Hospital, Rigshospitalet, Copenhagen 2100, Denmark
| | | | | | - Poul Hyttel
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark
| | - Dasaradhi Palakodeti
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore 560065, India
| | - Jan Gorodkin
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark; Center for Non-coding RNA in Technology and Health, University of Copenhagen, Frederiksberg 1871, Denmark
| | - Ravi S Muddashetty
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore 560065, India
| | - Morten Meyer
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, 5000 Odense, Denmark; Department of Neurology, Odense University Hospital, 5000 Odense, Denmark
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Kristine K Freude
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg 1870, Denmark.
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Root J, Merino P, Nuckols A, Johnson M, Kukar T. Lysosome dysfunction as a cause of neurodegenerative diseases: Lessons from frontotemporal dementia and amyotrophic lateral sclerosis. Neurobiol Dis 2021; 154:105360. [PMID: 33812000 PMCID: PMC8113138 DOI: 10.1016/j.nbd.2021.105360] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 03/16/2021] [Accepted: 03/29/2021] [Indexed: 12/11/2022] Open
Abstract
Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are fatal neurodegenerative disorders that are thought to exist on a clinical and pathological spectrum. FTD and ALS are linked by shared genetic causes (e.g. C9orf72 hexanucleotide repeat expansions) and neuropathology, such as inclusions of ubiquitinated, misfolded proteins (e.g. TAR DNA-binding protein 43; TDP-43) in the CNS. Furthermore, some genes that cause FTD or ALS when mutated encode proteins that localize to the lysosome or modulate endosome-lysosome function, including lysosomal fusion, cargo trafficking, lysosomal acidification, autophagy, or TFEB activity. In this review, we summarize evidence that lysosomal dysfunction, caused by genetic mutations (e.g. C9orf72, GRN, MAPT, TMEM106B) or toxic-gain of function (e.g. aggregation of TDP-43 or tau), is an important pathogenic disease mechanism in FTD and ALS. Further studies into the normal function of many of these proteins are required and will help uncover the mechanisms that cause lysosomal dysfunction in FTD and ALS. Mutations or polymorphisms in genes that encode proteins important for endosome-lysosome function also occur in other age-dependent neurodegenerative diseases, including Alzheimer's (e.g. APOE, PSEN1, APP) and Parkinson's (e.g. GBA, LRRK2, ATP13A2) disease. A more complete understanding of the common and unique features of lysosome dysfunction across the spectrum of neurodegeneration will help guide the development of therapies for these devastating diseases.
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Affiliation(s)
- Jessica Root
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta 30322, Georgia; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta 30322, Georgia
| | - Paola Merino
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta 30322, Georgia; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta 30322, Georgia
| | - Austin Nuckols
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta 30322, Georgia; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta 30322, Georgia
| | - Michelle Johnson
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta 30322, Georgia; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta 30322, Georgia
| | - Thomas Kukar
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta 30322, Georgia; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta 30322, Georgia; Department of Neurology, Emory University, School of Medicine, Atlanta 30322, Georgia.
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6
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Häkkinen S, Chu SA, Lee SE. Neuroimaging in genetic frontotemporal dementia and amyotrophic lateral sclerosis. Neurobiol Dis 2020; 145:105063. [PMID: 32890771 DOI: 10.1016/j.nbd.2020.105063] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/30/2020] [Accepted: 08/26/2020] [Indexed: 02/06/2023] Open
Abstract
Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) have a strong clinical, genetic and pathological overlap. This review focuses on the current understanding of structural, functional and molecular neuroimaging signatures of genetic FTD and ALS. We overview quantitative neuroimaging studies on the most common genes associated with FTD (MAPT, GRN), ALS (SOD1), and both (C9orf72), and summarize visual observations of images reported in the rarer genes (CHMP2B, TARDBP, FUS, OPTN, VCP, UBQLN2, SQSTM1, TREM2, CHCHD10, TBK1).
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Affiliation(s)
- Suvi Häkkinen
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Stephanie A Chu
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Suzee E Lee
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
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Fenoglio C, Scarpini E, Serpente M, Galimberti D. Role of Genetics and Epigenetics in the Pathogenesis of Alzheimer's Disease and Frontotemporal Dementia. J Alzheimers Dis 2019; 62:913-932. [PMID: 29562532 PMCID: PMC5870004 DOI: 10.3233/jad-170702] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alzheimer’s disease (AD) and frontotemporal dementia (FTD) represent the first cause of dementia in senile and pre-senile population, respectively. A percentage of cases have a genetic cause, inherited with an autosomal dominant pattern of transmission. The majority of cases, however, derive from complex interactions between a number of genetic and environmental factors. Gene variants may act as risk or protective factors. Their combination with a variety of environmental exposures may result in increased susceptibility to these diseases or may influence their course. The scenario is even more complicated considering the effect of epigenetics, which encompasses mechanisms able to alter the expression of genes without altering the DNA sequence. In this review, an overview of the current genetic and epigenetic progresses in AD and FTD will be provided, with particular focus on 1) causative genes, 2) genetic risk factors and disease modifiers, and 3) epigenetics, including methylation, non-coding RNAs and chromatin remodeling.
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Affiliation(s)
- Chiara Fenoglio
- Department of Pathophysiology and Transplantation, University of Milan, Centro Dino Ferrari, Fondazione Cá Granda, IRCCS Ospedale Maggiore Policlinico, Milan, Italy
| | - Elio Scarpini
- Department of Pathophysiology and Transplantation, University of Milan, Centro Dino Ferrari, Fondazione Cá Granda, IRCCS Ospedale Maggiore Policlinico, Milan, Italy
| | - Maria Serpente
- Department of Pathophysiology and Transplantation, University of Milan, Centro Dino Ferrari, Fondazione Cá Granda, IRCCS Ospedale Maggiore Policlinico, Milan, Italy
| | - Daniela Galimberti
- Department of Pathophysiology and Transplantation, University of Milan, Centro Dino Ferrari, Fondazione Cá Granda, IRCCS Ospedale Maggiore Policlinico, Milan, Italy
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Clayton EL, Milioto C, Muralidharan B, Norona FE, Edgar JR, Soriano A, Jafar-nejad P, Rigo F, Collinge J, Isaacs AM. Frontotemporal dementia causative CHMP2B impairs neuronal endolysosomal traffic-rescue by TMEM106B knockdown. Brain 2018; 141:3428-3442. [PMID: 30496365 PMCID: PMC6262218 DOI: 10.1093/brain/awy284] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 09/19/2018] [Accepted: 09/23/2018] [Indexed: 12/12/2022] Open
Abstract
Mutations in the endosome-associated protein CHMP2B cause frontotemporal dementia and lead to lysosomal storage pathology in neurons. We here report that physiological levels of mutant CHMP2B causes reduced numbers and significantly impaired trafficking of endolysosomes within neuronal dendrites, accompanied by increased dendritic branching. Mechanistically, this is due to the stable incorporation of mutant CHMP2B onto neuronal endolysosomes, which we show renders them unable to traffic within dendrites. This defect is due to the inability of mutant CHMP2B to recruit the ATPase VPS4, which is required for release of CHMP2B from endosomal membranes. Strikingly, both impaired trafficking and the increased dendritic branching were rescued by treatment with antisense oligonucleotides targeting the well validated frontotemporal dementia risk factor TMEM106B, which encodes an endolysosomal protein. This indicates that reducing TMEM106B levels can restore endosomal health in frontotemporal dementia. As TMEM106B is a risk factor for frontotemporal dementia caused by both C9orf72 and progranulin mutations, and antisense oligonucleotides are showing promise as therapeutics for neurodegenerative diseases, our data suggests a potential new strategy for treating the wide range of frontotemporal dementias associated with endolysosomal dysfunction.
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Affiliation(s)
- Emma L Clayton
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, UK
| | - Carmelo Milioto
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
- UK Dementia Research Institute at UCL, UCL Institute of Neurology, Queen Square, London, UK
| | - Bhavana Muralidharan
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
- UK Dementia Research Institute at UCL, UCL Institute of Neurology, Queen Square, London, UK
| | - Frances E Norona
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
| | - James R Edgar
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | | | | | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, California, USA
| | - John Collinge
- MRC Prion Unit at UCL, Institute of Prion Diseases, Queen Square, London, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
- UK Dementia Research Institute at UCL, UCL Institute of Neurology, Queen Square, London, UK
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Vandal SE, Zheng X, Ahmad ST. Molecular Genetics of Frontotemporal Dementia Elucidated by Drosophila Models-Defects in Endosomal⁻Lysosomal Pathway. Int J Mol Sci 2018; 19:ijms19061714. [PMID: 29890743 PMCID: PMC6032313 DOI: 10.3390/ijms19061714] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 01/31/2023] Open
Abstract
Frontotemporal dementia (FTD) is the second most common senile neurodegenerative disease. FTD is a heterogeneous disease that can be classified into several subtypes. A mutation in CHMP2B locus (CHMP2Bintron5), which encodes a component of endosomal sorting complex required for transport-III (ESCRT-III), is associated with a rare hereditary subtype of FTD linked to chromosome 3 (FTD-3). ESCRT is involved in critical cellular processes such as multivesicular body (MVB) formation during endosomal–lysosomal pathway and autophagy. ESCRT mutants causes diverse physiological defects primarily due to accumulation of endosomes and defective MVBs resulting in misregulation of signaling pathways. Charged multivesicular body protein 2B (CHMP2B) is important for neuronal physiology which especially rely on precise regulation of protein homeostasis due to their post-mitotic status. Drosophila has proven to be an excellent model for charaterization of mechanistic underpinning of neurodegenerative disorders including FTD. In this review, current understanding of various FTD-related mutations is discussed with a focus on Drosophila models of CHMP2Bintron5-associated FTD.
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Affiliation(s)
- Sarah E Vandal
- Department of Biology, Colby College, 5720 Mayflower Hill, Waterville, ME 04901, USA.
| | - Xiaoyue Zheng
- Department of Biology, Colby College, 5720 Mayflower Hill, Waterville, ME 04901, USA.
| | - S Tariq Ahmad
- Department of Biology, Colby College, 5720 Mayflower Hill, Waterville, ME 04901, USA.
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Serpente M, Galimberti D. Autosomal Dominant Frontotemporal Lobar Degeneration: From Genotype to Phenotype. NEURODEGENER DIS 2018. [DOI: 10.1007/978-3-319-72938-1_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Young JJ, Lavakumar M, Tampi D, Balachandran S, Tampi RR. Frontotemporal dementia: latest evidence and clinical implications. Ther Adv Psychopharmacol 2018; 8:33-48. [PMID: 29344342 PMCID: PMC5761910 DOI: 10.1177/2045125317739818] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 09/26/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Frontotemporal dementia (FTD) describes a cluster of neurocognitive syndromes that present with impairment of executive functioning, changes in behavior, and a decrease in language proficiency. FTD is the second most common form of dementia in those younger than 65 years and is expected to increase in prevalence as the population ages. This goal in our review is to describe advances in the understanding of neurobiological pathology, classification, assessment, and treatment of FTD syndromes. METHODS PubMed was searched to obtain reviews and studies that pertain to advancements in genetics, neurobiology, neuroimaging, classification, and treatment of FTD syndromes. Articles were chosen with a predilection to more recent preclinical/clinical trials and systematic reviews. RESULTS Recent reviews and trials indicate a significant advancement in the understanding of molecular and neurobiological clinical correlates to variants of FTD. Genetic and histopathologic markers have only recently been discovered in the past decade. Current therapeutic modalities are limited, with most studies reporting improvement in symptoms with nonpharmacological interventions. However, a small number of studies have reported improvement of behavioral symptoms with selective serotonin reuptake inhibitor (SSRI) treatment. Stimulants may help with disinhibition, apathy, and risk-taking behavior. Memantine and cholinesterase inhibitors have not demonstrated efficacy in ameliorating FTD symptoms. Antipsychotics have been used to treat agitation and psychosis, but safety concerns and side effect profiles limit utilization in the general FTD population. Nevertheless, recent breakthroughs in the understanding of FTD pathology have led to developments in pharmacological interventions that focus on producing treatments with autoimmune, genetic, and molecular targets. CONCLUSION FTD is an underdiagnosed group of neurological syndromes comprising multiple variants with distinct neurobiological profiles and presentations. Recent advances suggest there is an array of potential novel therapeutic targets, although data concerning their effectiveness are still preliminary or preclinical. Further studies are required to develop pharmacological interventions, as there are currently no US Food and Drug administration approved treatments to manage FTD syndromes.
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Affiliation(s)
- Juan Joseph Young
- Department of Psychiatry, MetroHealth Medical Center, Cleveland, OH, USA Case Western Reserve University, Cleveland, OH, USA
| | - Mallika Lavakumar
- Department of Psychiatry, MetroHealth Medical Center, Cleveland, OH, USA Case Western Reserve University, Cleveland, OH, USA
| | - Deena Tampi
- Mercy Regional Medical Center, 3700 Kolbe Rd, Lorain, OH 44053, USA
| | - Silpa Balachandran
- Department of Psychiatry, MetroHealth Medical Center, Cleveland, OH, USA Case Western Reserve University, Cleveland, OH, USA
| | - Rajesh R Tampi
- MetroHealth Medical Center, Case Western Reserve University School of Medicine, 2500 MetroHealth Drive, Cleveland, OH 44109, USA
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13
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Clayton EL, Mancuso R, Nielsen TT, Mizielinska S, Holmes H, Powell N, Norona F, Larsen JO, Milioto C, Wilson KM, Lythgoe MF, Ourselin S, Nielsen JE, Johannsen P, Holm I, Collinge J, Oliver PL, Gomez-Nicola D, Isaacs AM. Early microgliosis precedes neuronal loss and behavioural impairment in mice with a frontotemporal dementia-causing CHMP2B mutation. Hum Mol Genet 2017; 26:873-887. [PMID: 28093491 PMCID: PMC5409096 DOI: 10.1093/hmg/ddx003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 01/03/2017] [Indexed: 01/13/2023] Open
Abstract
Frontotemporal dementia (FTD)-causing mutations in the CHMP2B gene lead to the generation of mutant C-terminally truncated CHMP2B. We report that transgenic mice expressing endogenous levels of mutant CHMP2B developed late-onset brain volume loss associated with frank neuronal loss and FTD-like changes in social behaviour. These data are the first to show neurodegeneration in mice expressing mutant CHMP2B and indicate that our mouse model is able to recapitulate neurodegenerative changes observed in FTD. Neuroinflammation has been increasingly implicated in neurodegeneration, including FTD. Therefore, we investigated neuroinflammation in our CHMP2B mutant mice. We observed very early microglial proliferation that develops into a clear pro-inflammatory phenotype at late stages. Importantly, we also observed a similar inflammatory profile in CHMP2B patient frontal cortex. Aberrant microglial function has also been implicated in FTD caused by GRN, MAPT and C9orf72 mutations. The presence of early microglial changes in our CHMP2B mutant mice indicates neuroinflammation may be a contributing factor to the neurodegeneration observed in FTD.
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Affiliation(s)
- Emma L Clayton
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Renzo Mancuso
- Biological Sciences, University of Southampton, Southampton General Hospital, South Laboratory and Pathology Block, Tremona Road, Southampton SO166YD, UK
| | - Troels Tolstrup Nielsen
- Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Denmark
| | - Sarah Mizielinska
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Holly Holmes
- Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Nicholas Powell
- Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, 72 Huntley Street, London WC1E 6DD, UK.,Faculty of Health and Medical Sciences, Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Frances Norona
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Jytte Overgaard Larsen
- Translational Imaging Group, Centre for Medical Image Computing (CMIC), University College London, UK
| | - Carmelo Milioto
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Katherine M Wilson
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Mark F Lythgoe
- Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Sebastian Ourselin
- Faculty of Health and Medical Sciences, Department of Neuroscience and Pharmacology, Panum Institute, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Jörgen E Nielsen
- Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Denmark.,Section of Neurogenetics, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Peter Johannsen
- Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Denmark
| | - Ida Holm
- Laboratory for Experimental Neuropathology, Department of Pathology, Randers Hospital, DK-8930 Randers NØ, Denmark.,Institute of Clinical Medicine, Aarhus University, DK-8000 Aarhus C, Denmark
| | - John Collinge
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.,MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | | | - Peter L Oliver
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Diego Gomez-Nicola
- Biological Sciences, University of Southampton, Southampton General Hospital, South Laboratory and Pathology Block, Tremona Road, Southampton SO166YD, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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14
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Rostgaard N, Roos P, Budtz-Jørgensen E, Johannsen P, Waldemar G, Nørremølle A, Lindquist SG, Gydesen S, Brown JM, Collinge J, Isaacs AM, Nielsen TT, Nielsen JE. TMEM106B and ApoE polymorphisms in CHMP2B-mediated frontotemporal dementia (FTD-3). Neurobiol Aging 2017; 59:221.e1-221.e7. [PMID: 28888721 DOI: 10.1016/j.neurobiolaging.2017.06.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 06/24/2017] [Accepted: 06/30/2017] [Indexed: 12/12/2022]
Abstract
Single-nucleotide polymorphisms in the TMEM106B gene have been identified as a risk factor in frontotemporal dementia (FTD). The major allele of SNP rs3173615 is a risk factor in sporadic FTD, whereas the minor allele seems protective in GRN- and C9orf72-mediated FTD. The role of apolipoprotein E (ApoE) in FTD is uncertain, though an established risk factor in Alzheimer's disease. In a unique Danish family, inherited FTD is caused by a mutation in the CHMP2B gene located on chromosome 3 (FTD-3). In this family, both risk factors TMEM106B and ApoE were analyzed and correlated to age at onset (AAO) and progression in terms of age at institutionalization (AAI) and age at death (AAD). Although TMEM106B and CHMP2B share cellular function in that both localize to endolysosomes, TMEM106B genotypes appeared to have no influence on the clinical disease course. ApoE ε4 was found to be a protective factor with later AAO and AAI, whereas ε2 seemed to aggravate the disease with earlier AAO and AAD. These results indicate ApoE ε2 as a risk factor in FTD-3 and suggest a protective role of ε4.
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Affiliation(s)
- Nina Rostgaard
- Danish Dementia Research Centre, Department of Neurology, Rigshospitalet, University of Copenhagen, Section 6911, Copenhagen, Denmark
| | - Peter Roos
- Danish Dementia Research Centre, Department of Neurology, Rigshospitalet, University of Copenhagen, Section 6911, Copenhagen, Denmark.
| | | | - Peter Johannsen
- Danish Dementia Research Centre, Department of Neurology, Rigshospitalet, University of Copenhagen, Section 6911, Copenhagen, Denmark
| | - Gunhild Waldemar
- Danish Dementia Research Centre, Department of Neurology, Rigshospitalet, University of Copenhagen, Section 6911, Copenhagen, Denmark
| | - Anne Nørremølle
- Section of Neurogenetics, Institute of Cellular and Molecular Medicine, The Panum Institute, University of Copenhagen, Copenhagen N, Denmark
| | - Suzanne G Lindquist
- Danish Dementia Research Centre, Department of Neurology, Rigshospitalet, University of Copenhagen, Section 6911, Copenhagen, Denmark; Department of Clinical Genetics, Rigshospitalet, University of Copenhagen, Section 4062, Copenhagen, Denmark
| | - Susanne Gydesen
- Department of Psychiatry, Community Mental Health Services in Region Zealand, Nykøbing Sjælland, Denmark
| | - Jeremy M Brown
- Department of Neurology, Addenbrooke's Hospital, Cambridge, UK
| | - John Collinge
- MRC Prion Unit, Institute of Neurology, London, UK; Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK; UK Dementia Research Institute at UCL, UCL Institute of Neurology, London, UK
| | | | - Troels T Nielsen
- Danish Dementia Research Centre, Department of Neurology, Rigshospitalet, University of Copenhagen, Section 6911, Copenhagen, Denmark
| | - Jørgen E Nielsen
- Danish Dementia Research Centre, Department of Neurology, Rigshospitalet, University of Copenhagen, Section 6911, Copenhagen, Denmark; Section of Neurogenetics, Institute of Cellular and Molecular Medicine, The Panum Institute, University of Copenhagen, Copenhagen N, Denmark
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15
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Clayton EL, Mizielinska S, Edgar JR, Nielsen TT, Marshall S, Norona FE, Robbins M, Damirji H, Holm IE, Johannsen P, Nielsen JE, Asante EA, Collinge J, Isaacs AM. Frontotemporal dementia caused by CHMP2B mutation is characterised by neuronal lysosomal storage pathology. Acta Neuropathol 2015; 130:511-23. [PMID: 26358247 PMCID: PMC4575387 DOI: 10.1007/s00401-015-1475-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/01/2015] [Accepted: 09/02/2015] [Indexed: 12/13/2022]
Abstract
Mutations in the charged multivesicular body protein 2B (CHMP2B) cause frontotemporal dementia (FTD). We report that mice which express FTD-causative mutant CHMP2B at physiological levels develop a novel lysosomal storage pathology characterised by large neuronal autofluorescent aggregates. The aggregates are an early and progressive pathology that occur at 3 months of age and increase in both size and number over time. These autofluorescent aggregates are not observed in mice expressing wild-type CHMP2B, or in non-transgenic controls, indicating that they are a specific pathology caused by mutant CHMP2B. Ultrastructural analysis and immuno- gold labelling confirmed that they are derived from the endolysosomal system. Consistent with these findings, CHMP2B mutation patient brains contain morphologically similar autofluorescent aggregates. These aggregates occur significantly more frequently in human CHMP2B mutation brain than in neurodegenerative disease or age-matched control brains. These data suggest that lysosomal storage pathology is the major neuronal pathology in FTD caused by CHMP2B mutation. Recent evidence suggests that two other genes associated with FTD, GRN and TMEM106B are important for lysosomal function. Our identification of lysosomal storage pathology in FTD caused by CHMP2B mutation now provides evidence that endolysosomal dysfunction is a major degenerative pathway in FTD.
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Affiliation(s)
- Emma L Clayton
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Sarah Mizielinska
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - James R Edgar
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Troels Tolstrup Nielsen
- Neurogenetics Research Laboratory, Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Sarah Marshall
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Frances E Norona
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Miranda Robbins
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Hana Damirji
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Ida E Holm
- Laboratory for Experimental Neuropathology, Department of Pathology, Randers Hospital, 8930, Randers NØ, Denmark
- Institute of Clinical Medicine, Aarhus University, 8000, Aarhus C, Denmark
| | - Peter Johannsen
- Memory Clinic, Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen E Nielsen
- Neurogenetics Research Laboratory, Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Memory Clinic, Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Cellular and Molecular Medicine, Section of Neurogenetics, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Emmanuel A Asante
- MRC Prion Unit, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - John Collinge
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- MRC Prion Unit, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK.
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16
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Cai Y, An SSA, Kim S. Mutations in presenilin 2 and its implications in Alzheimer's disease and other dementia-associated disorders. Clin Interv Aging 2015; 10:1163-72. [PMID: 26203236 PMCID: PMC4507455 DOI: 10.2147/cia.s85808] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia. Mutations in the genes encoding presenilin 1 (PSEN1), presenilin 2 (PSEN2), and amyloid precursor protein have been identified as the main genetic causes of familial AD. To date, more than 200 mutations have been described worldwide in PSEN1, which is highly homologous with PSEN2, while mutations in PSEN2 have been rarely reported. We performed a systematic review of studies describing the mutations identified in PSEN2. Most PSEN2 mutations were detected in European and in African populations. Only two were found in Korean populations. Interestingly, PSEN2 mutations appeared not only in AD patients but also in patients with other disorders, including frontotemporal dementia, dementia with Lewy bodies, breast cancer, dilated cardiomyopathy, and Parkinson's disease with dementia. Here, we have summarized the PSEN2 mutations and the potential implications of these mutations in dementia-associated disorders.
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Affiliation(s)
- Yan Cai
- Department of Bionano Technology, Gachon Medical Research Institute, Gachon University, Seongnam-si, Gyeonggi-do, South Korea
| | - Seong Soo A An
- Department of Bionano Technology, Gachon Medical Research Institute, Gachon University, Seongnam-si, Gyeonggi-do, South Korea
| | - SangYun Kim
- Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam-si, Gyeonggi-do, South Korea
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17
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Frontotemporal Lobar Degeneration: Genetics and Clinical Phenotypes. NEURODEGENER DIS 2014. [DOI: 10.1007/978-1-4471-6380-0_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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18
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Cheruiyot A, Lee JA, Gao FB, Ahmad ST. Expression of mutant CHMP2B, an ESCRT-III component involved in frontotemporal dementia, causes eye deformities due to Notch misregulation in Drosophila. FASEB J 2013; 28:667-75. [PMID: 24158394 DOI: 10.1096/fj.13-234138] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Endosomal sorting complexes required for transport (ESCRTs) mediate sorting of ubiquitinated membrane proteins into multivesicular bodies en route to lysosomes for degradation. A mutation in CHMP2B (CHMP2B(Intron5), an ESCRT-III component) that is associated with a hereditary form of frontotemporal dementia (FTD3) disrupts the endosomal-lysosomal pathway and causes accumulation of autophagosomes and multilamellar structures. We previously demonstrated that expression of CHMP2B(Intron5) in the Drosophila eye using GMR-Gal4 causes misregulation of the Toll receptor pathway. Here, we show that ectopic expression of CHMP2B(Intron5) using eyeless-Gal4 (ey>CHMP2B(Intron5)), a driver with different spatiotemporal expression attributes than GMR-Gal4 in the Drosophila eye, causes eye deformities when compared to expression of wild-type CHMP2B (CHMP2B(WT)) and the Drosophila homologue of CHMP2B (CG4618). In addition, ey>CHMP2B(Intron5) flies showed defects in photoreceptor cell patterning and phototactic behavior. Furthermore, ey>CHMP2B(Intron5) flies showed accumulation of Notch in enlarged endosomes and up-regulation of Notch activity. Partial loss of Notch activity in ey>CHMP2B(Intron5) flies significantly rescued eye deformities, photoreceptor patterning defect, and phototactic behavior defect, indicating that these defects are primarily due to Notch misregulation. These results demonstrate that CHMP2B(Intron5) preferentially affects different receptor signaling pathways in a cellular and developmental context-dependent manner.
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Affiliation(s)
- Abigael Cheruiyot
- 2Department of Biology, Colby College, 5720 Mayflower Hill Dr., Waterville, ME 04901, USA.
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19
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Isaacs AM, Johannsen P, Holm I, Nielsen JE. Frontotemporal dementia caused by CHMP2B mutations. Curr Alzheimer Res 2011; 8:246-51. [PMID: 21222599 PMCID: PMC3182073 DOI: 10.2174/156720511795563764] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 11/30/2010] [Indexed: 01/13/2023]
Abstract
CHMP2B mutations are a rare cause of autosomal dominant frontotemporal dementia (FTD). The best studied example is frontotemporal dementia linked to chromosome 3 (FTD-3) which occurs in a large Danish family, with a further CHMP2B mutation identified in an unrelated Belgian familial FTD patient. These mutations lead to C-terminal truncations of the CHMP2B protein and we will review recent advances in our understanding of the molecular effects of these mutant truncated proteins on vesicular fusion events within the endosome-lysosome and autophagy degradation pathways. We will also review the clinical features of FTD caused by CHMP2B truncation mutations as well as new brain imaging and neuropathological findings. Finally, we collate the current data on CHMP2B missense mutations, which have been reported in FTD and motor neuron disease.
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Affiliation(s)
- A M Isaacs
- Department of Neurodegenerative Disease, VCL Institute of Neurology, Queen Square, London, UK.
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20
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Novel types of frontotemporal lobar degeneration: beyond tau and TDP-43. J Mol Neurosci 2011; 45:402-8. [PMID: 21603977 DOI: 10.1007/s12031-011-9551-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 05/09/2011] [Indexed: 12/30/2022]
Abstract
Most cases of frontotemporal lobar degeneration (FTLD) are characterized by the abnormal accumulation of either the microtubule-associated protein tau or the transactive response DNA-binding protein with M(r) 43 kDa, TDP-43 (FTLD-tau and FTLD-TDP, respectively). However, there remain ∼10% of cases, composed of a heterogenous collection of uncommon disorders, for which the molecular basis remains uncertain. In this review, we describe the characteristic genetic, clinical, and pathological features of the major tau/TDP-negative FTLD subtypes, with focus on recent advances in our understanding of their molecular basis. This includes the discovery that the pathological changes in atypical FTLD with ubiquitinated inclusions, neuronal intermediate filament inclusion disease, and basophilic inclusion body disease are immunoreactive for the fused in sarcoma (FUS) protein, resulting in the creation of a new molecular subgroup (FTLD-FUS), and studies clarifying the functional consequences of pathogenic CHMP2B mutations.
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Goldman JS, Rademakers R, Huey ED, Boxer AL, Mayeux R, Miller BL, Boeve BF. An algorithm for genetic testing of frontotemporal lobar degeneration. Neurology 2011; 76:475-83. [PMID: 21282594 DOI: 10.1212/wnl.0b013e31820a0d13] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE To derive an algorithm for genetic testing of patients with frontotemporal lobar degeneration (FTLD). METHODS A literature search was performed to review the clinical and pathologic phenotypes and family history associated with each FTLD gene. RESULTS Based on the literature review, an algorithm was developed to allow clinicians to use the clinical and neuroimaging phenotypes of the patient and the family history and autopsy information to decide whether or not genetic testing is warranted, and if so, the order for appropriate tests. CONCLUSIONS Recent findings in genetics, pathology, and imaging allow clinicians to use the clinical presentation of the patient with FTLD to inform genetic testing decisions.
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Affiliation(s)
- J S Goldman
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, 630 W. 168th St., Box 16, New York, NY 10032, USA.
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22
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The role of ESCRT proteins in fusion events involving lysosomes, endosomes and autophagosomes. Biochem Soc Trans 2011; 38:1469-73. [PMID: 21118109 DOI: 10.1042/bst0381469] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
ESCRT (endosomal sorting complex required for transport) proteins were originally identified for their role in delivering endocytosed proteins to the intraluminal vesicles of late-endosomal structures termed multivesicular bodies. Multivesicular bodies then fuse with lysosomes, leading to degradation of the internalized proteins. Four ESCRT complexes interact to concentrate cargo on the endosomal membrane, induce membrane curvature to form an intraluminal bud and finally pinch off the bud through a membrane-scission event to produce the intraluminal vesicle. Recent work suggests that ESCRT proteins are also required downstream of these events to enable fusion of multivesicular bodies with lysosomes. Autophagy is a related pathway required for the degradation of organelles, long-lived proteins and protein aggregates which also converges on lysosomes. The proteins or organelle to be degraded are encapsulated by an autophagosome that fuses either directly with a lysosome or with an endosome to form an amphisome, which then fuses with a lysosome. A common machinery is beginning to emerge that regulates fusion events in the multivesicular body and autophagy pathways, and we focus in the present paper on the role of ESCRT proteins. These fusion events have been implicated in diseases including frontotemporal dementia, Alzheimer's disease, lysosomal storage disorders, myopathies and bacterial pathogen invasion, and therefore further examination of the mechanisms involved may lead to new insight into disease pathogenesis and treatments.
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Kaivorinne AL, Krüger J, Udd B, Majamaa K, Remes AM. Mutations in CHMP2B are not a cause of frontotemporal lobar degeneration in Finnish patients. Eur J Neurol 2011; 17:1393-5. [PMID: 20412296 DOI: 10.1111/j.1468-1331.2010.03028.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Frontotemporal lobar degeneration (FTLD) is a genetically complex disorder. The majority of mutations linked to FTLD families are found in the microtubule-associated protein tau (MAPT) and progranulin (PGRN) genes. Mutations in the chromatin-modifying protein 2B gene (CHMP2B) have been identified in a few families. However, CHMP2B has been showed to be a rare cause of FTLD. Our aim was to determine the frequency of CHMP2B mutations in a clinical series of patients with FTLD in Northern Finland. PATIENTS AND METHODS We examined 72 (36 men) Finnish patients with FTLD. The mean age at onset was 58.9 (range 43–80). Symptoms of motor neuron disease (FTLDMND) were present in 12 patients (17%). Positive family history was detected in 28% of the patients. Mutations in MAPT and PGRN were excluded from these patients. All exons and exon–intron boundaries of the CHMP2B gene were sequenced. RESULTS No pathogenic CHMP2B mutations were found. A rare polymorphism in the non-coding region of exon 1 (rs36098294) and three other previously reported polymorphisms were detected. CONCLUSIONS Our results confirm that mutations in CHMP2B are not a common cause of FTLD. MAPT and PGRN mutations are also rare in Finnish population, suggesting that other, still unknown genetic factors may play a role in the pathogenesis of FTLD in Finnish population.
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Affiliation(s)
- A-L Kaivorinne
- Department of Clinical Medicine, Neurology, University of Oulu, Oulu, Finland
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24
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Neurology in the European Journal of Neurology. Eur J Neurol 2010. [DOI: 10.1111/j.1468-1331.2010.03248.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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25
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Ferrari R, Kapogiannis D, Huey ED, Grafman J, Hardy J, Momeni P. Novel missense mutation in charged multivesicular body protein 2B in a patient with frontotemporal dementia. Alzheimer Dis Assoc Disord 2010; 24:397-401. [PMID: 20592581 PMCID: PMC2974047 DOI: 10.1097/wad.0b013e3181df20c7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Frontotemporal dementia (FTD) is the second major cause of dementia in persons below the age of 65 years after Alzheimer disease. FTD is clinically, pathologically, and genetically heterogeneous and has been associated with mutations in different genes located on chromosomes 17, 9, and 3. In our study we report a novel heterozygous g.26218G>A variant in exon 6 of charged multivesicular body protein 2B (CHMP2B), predicted to cause the amino acid change p.Ser187Asn, in one patient diagnosed with FTD. We were not able to determine the mode of inheritance of the mutation as we did not have access to the genetically informative family members of the proband; those who were screened did not carry the variant. We did not find this variant in 273 White controls although we did find it in 6 of 94 African-American controls. Most of the mutations in CHMP2B which are considered pathogenic lead to partial deletion of the C-terminus region of CHMP2B protein. Based on previous reports and on our current data, missense mutations in this gene seem unlikely to be pathogenic. The pathogenicity of CHMP2B mutations requires further investigation.
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Affiliation(s)
- Raffaele Ferrari
- Texas Tech University, Health Sciences Center, Dept. of Internal Medicine, 3601 4 street, Lubbock, TX, 79430, USA
- Department of Molecular Neuroscience and Reta Lila Weston Laboratories, Institute of Neurology, UCL, 9th Floor, Queen Square House Queen Square, London WC1N 3BG England
| | - Dimitrios Kapogiannis
- Cognitive Neuroscience Section, National Institute of Neurological Disorders and Stroke Bldg. 10 room 7D43, MSC 1440 NIH Bethesda, Maryland 20892-1440, USA
| | - Edward D. Huey
- Cognitive Neuroscience Section, National Institute of Neurological Disorders and Stroke Bldg. 10 room 7D43, MSC 1440 NIH Bethesda, Maryland 20892-1440, USA
- Litwin-Zucker Center for Research on Alzheimer’s Disease and Memory Disorders, North Shore/Long Island Jewish Healthcare System, 350 Community Drive, Manhasset, NY 11030-3816, USA
| | - Jordan Grafman
- Cognitive Neuroscience Section, National Institute of Neurological Disorders and Stroke Bldg. 10 room 7D43, MSC 1440 NIH Bethesda, Maryland 20892-1440, USA
| | - John Hardy
- Laboratory of Neurogenetics, building 35, National Institute on Aging, National Institute of Health, Bethesda, Maryland
- Department of Molecular Neuroscience and Reta Lila Weston Laboratories, Institute of Neurology, UCL, 9th Floor, Queen Square House Queen Square, London WC1N 3BG England
| | - Parastoo Momeni
- Texas Tech University, Health Sciences Center, Dept. of Internal Medicine, 3601 4 street, Lubbock, TX, 79430, USA
- Texas Tech University, Health Sciences Center, Department of Pharmacology and Neuroscience, 3601 4 street, Lubbock, TX, 79430, USA
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Urwin H, Josephs KA, Rohrer JD, Mackenzie IR, Neumann M, Authier A, Seelaar H, Van Swieten JC, Brown JM, Johannsen P, Nielsen JE, Holm IE, Dickson DW, Rademakers R, Graff-Radford NR, Parisi JE, Petersen RC, Hatanpaa KJ, White III CL, Weiner MF, Geser F, Van Deerlin VM, Trojanowski JQ, Miller BL, Seeley WW, van der Zee J, Kumar-Singh S, Engelborghs S, De Deyn PP, Van Broeckhoven C, Bigio EH, Deng HX, Halliday GM, Kril JJ, Munoz DG, Mann DM, Pickering-Brown SM, Doodeman V, Adamson G, Ghazi-Noori S, Fisher EMC, Holton JL, Revesz T, Rossor MN, Collinge J, Mead S, Isaacs AM. FUS pathology defines the majority of tau- and TDP-43-negative frontotemporal lobar degeneration. Acta Neuropathol 2010; 120:33-41. [PMID: 20490813 PMCID: PMC2887939 DOI: 10.1007/s00401-010-0698-6] [Citation(s) in RCA: 185] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 04/20/2010] [Accepted: 05/08/2010] [Indexed: 12/12/2022]
Abstract
Through an international consortium, we have collected 37 tau- and TAR DNA-binding protein 43 (TDP-43)-negative frontotemporal lobar degeneration (FTLD) cases, and present here the first comprehensive analysis of these cases in terms of neuropathology, genetics, demographics and clinical data. 92% (34/37) had fused in sarcoma (FUS) protein pathology, indicating that FTLD-FUS is an important FTLD subtype. This FTLD-FUS collection specifically focussed on aFTLD-U cases, one of three recently defined subtypes of FTLD-FUS. The aFTLD-U subtype of FTLD-FUS is characterised clinically by behavioural variant frontotemporal dementia (bvFTD) and has a particularly young age of onset with a mean of 41 years. Further, this subtype had a high prevalence of psychotic symptoms (36% of cases) and low prevalence of motor symptoms (3% of cases). We did not find FUS mutations in any aFTLD-U case. To date, the only subtype of cases reported to have ubiquitin-positive but tau-, TDP-43- and FUS-negative pathology, termed FTLD-UPS, is the result of charged multivesicular body protein 2B gene (CHMP2B) mutation. We identified three FTLD-UPS cases, which are negative for CHMP2B mutation, suggesting that the full complement of FTLD pathologies is yet to be elucidated.
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Affiliation(s)
- Hazel Urwin
- MRC Prion Unit, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | | | - Jonathan D. Rohrer
- Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Ian R. Mackenzie
- Department of Pathology and Laboratory Medicine, Vancouver General Hospital, University of British Columbia, Vancouver, BC Canada
| | - Manuela Neumann
- Institute of Neuropathology, University Hospital of Zurich, Zurich, Switzerland
| | - Astrid Authier
- MRC Prion Unit, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Harro Seelaar
- Department of Neurology, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - John C. Van Swieten
- Department of Neurology, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jeremy M. Brown
- Department of Neurology, Addenbrooke’s Hospital, Cambridge, UK
| | - Peter Johannsen
- Memory Disorders Research Unit, Department of Neurology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Jorgen E. Nielsen
- Memory Disorders Research Unit, Department of Neurology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
- Department of Cellular and Molecular Medicine, Section of Neurogenetics, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Ida E. Holm
- Department of Pathology, Randers Hospital, Randers and Laboratory for Experimental Neuropathology, Danish Neuroscience Center, Aarhus University Hospital, Aarhus, Denmark
| | | | | | - Rosa Rademakers
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL USA
| | | | - Joseph E. Parisi
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN USA
| | | | - Kimmo J. Hatanpaa
- Department of Pathology, University of Texas Southwestern Medical School, Dallas, TX USA
| | - Charles L. White III
- Department of Pathology, University of Texas Southwestern Medical School, Dallas, TX USA
| | - Myron F. Weiner
- Departments of Psychiatry and Neurology, University of Texas Southwestern Medical School, Dallas, TX USA
| | - Felix Geser
- Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, USA
| | - Vivianna M. Van Deerlin
- Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, USA
| | - John Q. Trojanowski
- Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, USA
| | - Bruce L. Miller
- UCSF Department of Neurology, Memory and Aging Center, San Francisco, CA USA
| | - William W. Seeley
- UCSF Department of Neurology, Memory and Aging Center, San Francisco, CA USA
| | - Julie van der Zee
- VIB Department of Molecular Genetics, Neurodegenerative Brain Diseases Group, Antwerpen, Belgium
- Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium
| | - Samir Kumar-Singh
- VIB Department of Molecular Genetics, Neurodegenerative Brain Diseases Group, Antwerpen, Belgium
- Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium
| | - Sebastiaan Engelborghs
- Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium
- Department of Neurology, Memory Clinic, ZNA Middelheim, Antwerpen, Belgium
| | - Peter P. De Deyn
- Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium
- Department of Neurology, Memory Clinic, ZNA Middelheim, Antwerpen, Belgium
| | - Christine Van Broeckhoven
- VIB Department of Molecular Genetics, Neurodegenerative Brain Diseases Group, Antwerpen, Belgium
- Institute Born-Bunge, University of Antwerp, Antwerpen, Belgium
| | - Eileen H. Bigio
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL USA
| | - Han-Xiang Deng
- Department of Neurology and Clinical Neurosciences, Feinberg School of Medicine, Northwestern University, Chicago, IL USA
| | - Glenda M. Halliday
- Prince of Wales Medical Research Institute, University of New South Wales, Sydney, NSW Australia
| | - Jillian J. Kril
- Disciplines of Medicine and Pathology, University of Sydney, Sydney, NSW Australia
| | - David G. Munoz
- Department of Pathology, Saint Michael’s Hospital, University of Toronto, Toronto, ON Canada
| | - David M. Mann
- Clinical Neuroscience Research Group, School of Translational Medicine, Greater Manchester Neurosciences Centre, University of Manchester, Salford, UK
| | - Stuart M. Pickering-Brown
- Clinical Neurosciences Research Group, Faculty of Human and Medical Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT UK
| | - Valerie Doodeman
- Department of Clinical Genetics, VU University Medical Center, Amsterdam, The Netherlands
| | - Gary Adamson
- MRC Prion Unit, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Shabnam Ghazi-Noori
- MRC Prion Unit, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Elizabeth M. C. Fisher
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Janice L. Holton
- Department of Neuropathology, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Tamas Revesz
- Department of Neuropathology, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Martin N. Rossor
- Dementia Research Centre, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - John Collinge
- MRC Prion Unit, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Simon Mead
- MRC Prion Unit, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
| | - Adrian M. Isaacs
- MRC Prion Unit, UCL Institute of Neurology, Queen Square, London, WC1N 3BG UK
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Abstract
Behavioral changes and cognitive decline are the core clinical manifestations in the behavioral variant of frontotemporal dementia (bv-FTD). The behavioral changes may include characteristic stereotypic movements. These movements, although without clear purpose, are not involuntary. Involuntary movements are usually not seen in FTD.Two patients with involuntary choreoathetoid movements but otherwise presenting a bv-FTD-phenotype were referred and Huntington's disease (HD) was suspected. The diagnoses of bv-FTD were made after comprehensive assessment and exclusion of other diagnoses, including HD and Huntington's disease-like (HDL) phenotypes. Although a definite diagnosis will require neuropathological confirmation, we conclude that a HDL phenotype may be part of the clinical spectrum of the bv-FTD phenotype.
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Urwin H, Authier A, Nielsen JE, Metcalf D, Powell C, Froud K, Malcolm DS, Holm I, Johannsen P, Brown J, Fisher EMC, van der Zee J, Bruyland M, Van Broeckhoven C, Collinge J, Brandner S, Futter C, Isaacs AM. Disruption of endocytic trafficking in frontotemporal dementia with CHMP2B mutations. Hum Mol Genet 2010; 19:2228-38. [PMID: 20223751 PMCID: PMC2865375 DOI: 10.1093/hmg/ddq100] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mutations in CHMP2B cause frontotemporal dementia (FTD) in a large Danish pedigree, which is termed FTD linked to chromosome 3 (FTD-3), and also in an unrelated familial FTD patient. CHMP2B is a component of the ESCRT-III complex, which is required for function of the multivesicular body (MVB), an endosomal structure that fuses with the lysosome to degrade endocytosed proteins. We report a novel endosomal pathology in CHMP2B mutation-positive patient brains and also identify and characterize abnormal endosomes in patient fibroblasts. Functional studies demonstrate a specific disruption of endosome–lysosome fusion but not protein sorting by the MVB. We provide evidence for a mechanism for impaired endosome–lysosome fusion whereby mutant CHMP2B constitutively binds to MVBs and prevents recruitment of proteins necessary for fusion to occur, such as Rab7. The fusion of endosomes with lysosomes is required for neuronal function and the data presented therefore suggest a pathogenic mechanism for FTD caused by CHMP2B mutations.
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Affiliation(s)
- Hazel Urwin
- MRC Prion Unit, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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Ahmad ST, Sweeney ST, Lee JA, Sweeney NT, Gao FB. Genetic screen identifies serpin5 as a regulator of the toll pathway and CHMP2B toxicity associated with frontotemporal dementia. Proc Natl Acad Sci U S A 2009; 106:12168-73. [PMID: 19581577 PMCID: PMC2715505 DOI: 10.1073/pnas.0903134106] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Indexed: 12/22/2022] Open
Abstract
Frontotemporal dementia (FTD) is the most common form of dementia before 60 years of age. Rare pathogenic mutations in CHMP2B, which encodes a component of the endosomal sorting complex required for transport (ESCRT-III), are associated with FTD linked to chromosome 3 (FTD3). Animal models of FTD3 have not yet been reported, and what signaling pathways are misregulated by mutant CHMP2B in vivo is unknown. Here we report the establishment of a Drosophila model of FTD3 and show the genetic interactions between mutant CHMP2B and other components of ESCRT. Through an unbiased genome-wide screen, we identified 29 modifier loci and found that serpin5 (Spn5), a largely uncharacterized serine protease inhibitor, suppresses the melanization phenotype induced by mutant CHMP2B in the fly eye. We also found that Spn5 is a negative regulator of the Toll pathway and functions extracellularly, likely by blocking the proteolytic activation of Spaetzle, the Toll receptor ligand. Moreover, Spn5 inhibited activation of the Toll pathway by mutant CHMP2B. Our findings identify Spn5 as a regulator of the Toll pathway and CHMP2B toxicity and show that the Toll pathway is a major signaling pathway misregulated by mutant CHMP2B in vivo. This fly model will be useful to further dissect genetic pathways that are potentially relevant to the pathogenesis and treatment of FTD.
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Affiliation(s)
- S. Tariq Ahmad
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
| | - Sean T. Sweeney
- Department of Biology, University of York, P.O. Box 373, York YO10 5YW, United Kingdom; and
| | - Jin-A Lee
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
| | - Neal T. Sweeney
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
- Neuroscience Graduate Program, University of California, San Francisco, CA 94158
| | - Fen-Biao Gao
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
- Neuroscience Graduate Program, University of California, San Francisco, CA 94158
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Eskildsen SF, Østergaard LR, Rodell AB, Østergaard L, Nielsen JE, Isaacs AM, Johannsen P. Cortical volumes and atrophy rates in FTD-3 CHMP2B mutation carriers and related non-carriers. Neuroimage 2009; 45:713-21. [DOI: 10.1016/j.neuroimage.2008.12.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Revised: 11/06/2008] [Accepted: 12/08/2008] [Indexed: 01/08/2023] Open
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Abstract
Mutations in the CHMP2B (charged multivesicular body protein 2B) gene that lead to C-terminal truncations of the protein can cause frontotemporal dementia. CHMP2B is a member of ESCRT-III (endosomal sorting complex required for transport III), which is required for formation of the multivesicular body, a late endosomal structure that fuses with the lysosome to degrade endocytosed proteins. Overexpression of mutant C-terminally truncated CHMP2B proteins produces an enlarged endosomal phenotype in PC12 and human neuroblastoma cells, which is likely to be due to a dominant-negative effect on endosomal function. Disruption of normal endosomal trafficking is likely to affect the transport of neuronal growth factors and autophagic clearance of proteins, both of which could contribute to neurodegeneration in frontotemporal dementia.
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