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Chen M, Xu L, Wu Y, Soba P, Hu C. The organization and function of the Golgi apparatus in dendrite development and neurological disorders. Genes Dis 2023; 10:2425-2442. [PMID: 37554209 PMCID: PMC10404969 DOI: 10.1016/j.gendis.2022.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 09/13/2022] [Accepted: 11/05/2022] [Indexed: 12/24/2022] Open
Abstract
Dendrites are specialized neuronal compartments that sense, integrate and transfer information in the neural network. Their development is tightly controlled and abnormal dendrite morphogenesis is strongly linked to neurological disorders. While dendritic morphology ranges from relatively simple to extremely complex for a specified neuron, either requires a functional secretory pathway to continually replenish proteins and lipids to meet dendritic growth demands. The Golgi apparatus occupies the center of the secretory pathway and is regulating posttranslational modifications, sorting, transport, and signal transduction, as well as acting as a non-centrosomal microtubule organization center. The neuronal Golgi apparatus shares common features with Golgi in other eukaryotic cell types but also forms distinct structures known as Golgi outposts that specifically localize in dendrites. However, the organization and function of Golgi in dendrite development and its impact on neurological disorders is just emerging and so far lacks a systematic summary. We describe the organization of the Golgi apparatus in neurons, review the current understanding of Golgi function in dendritic morphogenesis, and discuss the current challenges and future directions.
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Affiliation(s)
- Meilan Chen
- Key Laboratory of Brain, Cognition and Education Sciences, Ministry of Education Institute for Brain, Science and Rehabilitation, South China Normal University, Guangzhou, Guangdong 510631, China
- Department of Ophthalmology, Guangdong Second Provincial General Hospital, Guangzhou, Guangdong 510320, China
| | - Lu Xu
- Key Laboratory of Brain, Cognition and Education Sciences, Ministry of Education Institute for Brain, Science and Rehabilitation, South China Normal University, Guangzhou, Guangdong 510631, China
| | - Yi Wu
- Department of Ophthalmology, Guangdong Second Provincial General Hospital, Guangzhou, Guangdong 510320, China
| | - Peter Soba
- LIMES Institute, Department of Molecular Brain Physiology and Behavior, University of Bonn, Bonn 53115, Germany
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91054, Germany
| | - Chun Hu
- Key Laboratory of Brain, Cognition and Education Sciences, Ministry of Education Institute for Brain, Science and Rehabilitation, South China Normal University, Guangzhou, Guangdong 510631, China
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2
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Koyano S, Yagishita S, Tada M, Doi H, Uchihara T, Tanaka F. Parallel Appearance of Polyglutamine and Transactivation-Responsive DNA-Binding Protein 43 and Their Complementary Subcellular Localization in Brains of Patients With Spinocerebellar Ataxia Type 2. J Neuropathol Exp Neurol 2022; 81:535-544. [PMID: 35511239 DOI: 10.1093/jnen/nlac032] [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] [Indexed: 12/12/2022] Open
Abstract
Spinocerebellar ataxia type 2 (SCA2) is caused by mutations in the ATXN2 gene in which toxic effects are triggered by expanded polyglutamine repeats within ataxin-2. SCA2 is accompanied by motor neuron degeneration as occurs in amyotrophic lateral sclerosis (ALS). We investigated the distribution patterns of ataxin-2 and transactivation-responsive DNA-binding protein 43 (TDP-43), a major disease-related protein in ALS, in the CNS of 3 SCA2 patients. Phosphorylated TDP-43 (pTDP-43)-positive lesions were widely distributed throughout the CNS and generally overlapped with 1C2 (expanded polyglutamine)-immunoreactive lesions. This distribution pattern is different from the pattern in limbic-predominant age-related TDP-43 encephalopathy. In SCA2, double immunostaining of TDP-43 and 1C2 in motor neurons revealed 3 staining patterns: cytoplasmic 1C2 and nuclear TDP-43, nucleocytoplasmic 1C2 and nuclear TDP-43, and nuclear 1C2 and cytoplasmic TDP-43, which reflect the early, active, and final stages of pathological change, respectively. The translocation of TDP-43 from the nucleus to the cytoplasm along with the translocation of 1C2 in the opposite direction indicates that nuclear accumulation of the disease-specific protein ataxin-2 affects the intracellular dynamics of TDP-43. Such a close interrelationship between mutant ataxin-2 and TDP-43 in the cell might account for the similarity of their distribution in the CNS of patients with SCA2.
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Affiliation(s)
- Shigeru Koyano
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan.,Laboratory of Structural Neuropathology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.,Department of Neurology, Yokohama Minami Kyosai Hospital, Yokohama, Kanagawa, Japan
| | - Saburo Yagishita
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan.,Laboratory of Structural Neuropathology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Mikiko Tada
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Hiroshi Doi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Toshiki Uchihara
- Laboratory of Structural Neuropathology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.,Neurology Clinic with Neuromorphomics Laboratory, Nitobe-Memorial Nakano General Hospital, Tokyo, Japan
| | - Fumiaki Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
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3
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Couratier P, Lautrette G, Luna JA, Corcia P. Phenotypic variability in amyotrophic lateral sclerosis. Rev Neurol (Paris) 2021; 177:536-543. [PMID: 33902945 DOI: 10.1016/j.neurol.2021.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/14/2021] [Accepted: 03/16/2021] [Indexed: 10/21/2022]
Abstract
Clinically, ALS phenotypes depend on the areas of the body that are affected, the different degrees of involvement of upper and lower motor neurons, the degrees of involvement of other systems, particularly cognition and behavior, and rates of progression. Phenotypic variability of ALS is characteristic and can be declined on the distribution of motor manifestations but also on the presence of extra-motor signs present in a variable manner in ALS patients. Neuropathologically, ALS is defined by the loss of UMN and LMN and the presence of two representative motor neuronal cytoplasmic inclusions, Bunina bodies and 43kDa Transactivation Response DNA Binding Protein (TDP-43) - positive cytoplasmic inclusions. The distribution of cytopathology and neuronal loss in patients is variable and this variability is directly related to phenotypic variability. Key regulators of phenotypic variability in ALS have not been determined. The functional decrement of TDP-43, and region-specific neuronal susceptibility to ALS, may be involved. Due to the selective vulnerability among different neuronal systems, lesions are multicentric, region-oriented, and progress at different rates. They may vary from patient to patient, which may be linked to the clinicopathological variability across patients.
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Affiliation(s)
- P Couratier
- Service de neurologie, centre de référence maladies rares SLA et autres maladies du neurone moteur, CHU de Limoges, Limoges, France; Inserm, IRD, U1094 Tropical Neuroepidemiology, Institute of Epidemiology and Tropical Neurology, GEIST, université de Limoges, CHU de Limoges, Limoges, France; Fédération des Centres SLA de Limoges et Tours, Litorals, Limoges, France.
| | - G Lautrette
- Service de neurologie, centre de référence maladies rares SLA et autres maladies du neurone moteur, CHU de Limoges, Limoges, France; Fédération des Centres SLA de Limoges et Tours, Litorals, Limoges, France
| | - J A Luna
- Inserm, IRD, U1094 Tropical Neuroepidemiology, Institute of Epidemiology and Tropical Neurology, GEIST, université de Limoges, CHU de Limoges, Limoges, France
| | - P Corcia
- Fédération des Centres SLA de Limoges et Tours, Litorals, Limoges, France; Centre de référence maladies rares SLA et autres maladies du neurone moteur, CHU Bretonneau, Tours, France
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4
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Schellino R, Boido M, Vercelli A. The Dual Nature of Onuf's Nucleus: Neuroanatomical Features and Peculiarities, in Health and Disease. Front Neuroanat 2020; 14:572013. [PMID: 33013330 PMCID: PMC7500142 DOI: 10.3389/fnana.2020.572013] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 08/19/2020] [Indexed: 12/13/2022] Open
Abstract
Onuf's nucleus is a small group of neurons located in the ventral horns of the sacral spinal cord. The motor neurons (MNs) of Onuf's nucleus innervate striated voluntary muscles of the pelvic floor and are histologically and biochemically comparable to the other somatic spinal MNs. However, curiously, these neurons also show some autonomic-like features as, for instance, they receive a strong peptidergic innervation. The review provides an overview of the histological, biochemical, metabolic, and gene expression peculiarities of Onuf's nucleus. Moreover, it describes the aging-related pathologies as well as several traumatic and neurodegenerative disorders in which its neurons are involved: indeed, Onuf's nucleus is affected in Parkinson's disease (PD) and Shy-Drager Syndrome (SDS), whereas it is spared in Amyotrophic Lateral Sclerosis (ALS), Spinal Muscular Atrophy (SMA), Duchenne Muscular Dystrophy (DMD). We summarize here the milestone studies that have contributed to clarifying the nature of Onuf's neurons and in understanding what makes them either vulnerable or resistant to damage. Altogether, these works can offer the possibility to develop new therapeutic strategies for counteracting neurodegeneration.
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Affiliation(s)
- Roberta Schellino
- Department of Neuroscience Rita Levi Montalcini, University of Turin, Turin, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, Turin, Italy
| | - Marina Boido
- Department of Neuroscience Rita Levi Montalcini, University of Turin, Turin, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, Turin, Italy.,National Institute of Neuroscience, Turin, Italy
| | - Alessandro Vercelli
- Department of Neuroscience Rita Levi Montalcini, University of Turin, Turin, Italy.,Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, Turin, Italy.,National Institute of Neuroscience, Turin, Italy
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Park JH, Chung CG, Seo J, Lee BH, Lee YS, Kweon JH, Lee SB. C9orf72-Associated Arginine-Rich Dipeptide Repeat Proteins Reduce the Number of Golgi Outposts and Dendritic Branches in Drosophila Neurons. Mol Cells 2020; 43:821-830. [PMID: 32975212 PMCID: PMC7528685 DOI: 10.14348/molcells.2020.0130] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/13/2020] [Accepted: 08/30/2020] [Indexed: 12/11/2022] Open
Abstract
Altered dendritic morphology is frequently observed in various neurological disorders including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), but the cellular and molecular basis underlying these pathogenic dendritic abnormalities remains largely unclear. In this study, we investigated dendritic morphological defects caused by dipeptide repeat protein (DPR) toxicity associated with G4C2 expansion mutation of C9orf72 (the leading genetic cause of ALS and FTD) in Drosophila neurons and characterized the underlying pathogenic mechanisms. Among the five DPRs produced by repeat-associated non-ATG translation of G4C2 repeats, we found that arginine-rich DPRs (PR and GR) led to the most significant reduction in dendritic branches and plasma membrane (PM) supply in Class IV dendritic arborization (C4 da) neurons. Furthermore, expression of PR and GR reduced the number of Golgi outposts (GOPs) in dendrites. In Drosophila brains, expression of PR, but not GR, led to a significant reduction in the mRNA level of CrebA, a transcription factor regulating the formation of GOPs. Overexpressing CrebA in PR-expressing C4 da neurons mitigated PM supply defects and restored the number of GOPs, but the number of dendritic branches remained unchanged, suggesting that other molecules besides CrebA may be involved in dendritic branching. Taken together, our results provide valuable insight into the understanding of dendritic pathology associated with C9-ALS/FTD.
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Affiliation(s)
- Jeong Hyang Park
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 4988, Korea
- These authors contributed equally to this work
| | - Chang Geon Chung
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 4988, Korea
- These authors contributed equally to this work
| | - Jinsoo Seo
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 4988, Korea
| | - Byung-Hoon Lee
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 4988, Korea
- Department of New Biology, DGIST, Daegu 42988, Korea
| | - Young-Sam Lee
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 4988, Korea
- Department of New Biology, DGIST, Daegu 42988, Korea
- Well Aging Research Center, Division of Biotechnology, DGIST, Daegu 2988, Korea
| | - Jung Hyun Kweon
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
| | - Sung Bae Lee
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 4988, Korea
- Well Aging Research Center, Division of Biotechnology, DGIST, Daegu 2988, Korea
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Herzog JJ, Xu W, Deshpande M, Rahman R, Suib H, Rodal AA, Rosbash M, Paradis S. TDP-43 dysfunction restricts dendritic complexity by inhibiting CREB activation and altering gene expression. Proc Natl Acad Sci U S A 2020; 117:11760-11769. [PMID: 32393629 PMCID: PMC7260973 DOI: 10.1073/pnas.1917038117] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are two related neurodegenerative diseases that present with similar TDP-43 pathology in patient tissue. TDP-43 is an RNA-binding protein which forms aggregates in neurons of ALS and FTD patients as well as in a subset of patients diagnosed with other neurodegenerative diseases. Despite our understanding that TDP-43 is essential for many aspects of RNA metabolism, it remains obscure how TDP-43 dysfunction contributes to neurodegeneration. Interestingly, altered neuronal dendritic morphology is a common theme among several neurological disorders and is thought to precede neurodegeneration. We previously found that both TDP-43 overexpression (OE) and knockdown (KD) result in reduced dendritic branching of cortical neurons. In this study, we used TRIBE (targets of RNA-binding proteins identified by editing) as an approach to identify signaling pathways that regulate dendritic branching downstream of TDP-43. We found that TDP-43 RNA targets are enriched for pathways that signal to the CREB transcription factor. We further found that TDP-43 dysfunction inhibits CREB activation and CREB transcriptional output, and restoring CREB signaling rescues defects in dendritic branching. Finally, we demonstrate, using RNA sequencing, that TDP-43 OE and KD cause similar changes in the abundance of specific messenger RNAs, consistent with their ability to produce similar morphological defects. Our data therefore provide a mechanism by which TDP-43 dysfunction interferes with dendritic branching, and may define pathways for therapeutic intervention in neurodegenerative diseases.
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Affiliation(s)
- Josiah J Herzog
- Department of Biology, Brandeis University, Waltham, MA 02453
- Volen Center for Complex Systems, Brandeis University, Waltham, MA 02453
| | - Weijin Xu
- Department of Biology, Brandeis University, Waltham, MA 02453
- Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02453
| | - Mugdha Deshpande
- Department of Biology, Brandeis University, Waltham, MA 02453
- Volen Center for Complex Systems, Brandeis University, Waltham, MA 02453
| | - Reazur Rahman
- Department of Biology, Brandeis University, Waltham, MA 02453
- Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02453
| | - Hannah Suib
- Department of Biology, Brandeis University, Waltham, MA 02453
- Volen Center for Complex Systems, Brandeis University, Waltham, MA 02453
| | - Avital A Rodal
- Department of Biology, Brandeis University, Waltham, MA 02453
| | - Michael Rosbash
- Department of Biology, Brandeis University, Waltham, MA 02453;
- Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02453
| | - Suzanne Paradis
- Department of Biology, Brandeis University, Waltham, MA 02453;
- Volen Center for Complex Systems, Brandeis University, Waltham, MA 02453
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7
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Takeda T, Kitagawa K, Arai K. Phenotypic variability and its pathological basis in amyotrophic lateral sclerosis. Neuropathology 2019; 40:40-56. [PMID: 31802540 DOI: 10.1111/neup.12606] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 12/19/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is characterized by its inherent clinicopathological variability. The concurrence of upper and lower motor neuron signs is a common feature in the majority of patients with ALS. However, some patients manifest an atypical clinical course, with only upper or lower motor neuron signs, or various extra-motor symptoms including cognitive dysfunction, parkinsonism, autonomic dysfunction, or ophthalmoparesis. This variability indicates different manifestations of ALS and is reflected by ALS pathology spreading into the central nervous system. The presence of cytoplasmic inclusions positive for transactivation response DNA-binding protein 43 kDa (TDP-43) is a key feature in ALS. Loss of TDP-43 from the nucleus and its subsequent aggregation in the cytoplasm may occur in susceptible regions and may be associated with neuronal loss. However, in some regions, there is no apparent neuronal loss while TDP-43 accumulation is evident; in contrast, in other regions, neuronal loss is apparent without any evidence of TDP-43 accumulation. Therefore, in addition to TDP-43 dysfunction, underlying region-specific cellular vulnerability may exist in the upper and lower motor neurons and frontotemporal system in patients with ALS. The microscopic discrepancy and selective vulnerability may be linked to the macroscopic propensities of the sites of onset, and may also determine the direction and rate of progression of the lesions. Thus, there may be multicentric sites of onset, region-oriented disease development, and different speeds of disease progression across patients with ALS. ALS lesions occur in motor-related areas but may spread to neighboring areas. However, since lesions may spread in a discontinuous manner, and the dynamics of disease propagation have not been able to be identified, it remains controversial whether the stepwise appearance of TDP-43-positive inclusions is based on direct cell-to-cell protein propagation. Further understanding of the phenotypic variability of ALS and its pathological basis may serve as a guide for investigating the underlying pathogenesis of ALS.
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Affiliation(s)
- Takahiro Takeda
- Department of Neurology, National Hospital Organization Chibahigashi National Hospital, Chiba, Japan.,Department of Neurology, Tokyo Women's Medical University, Tokyo, Japan
| | - Kazuo Kitagawa
- Department of Neurology, Tokyo Women's Medical University, Tokyo, Japan
| | - Kimihito Arai
- Department of Neurology, National Hospital Organization Chibahigashi National Hospital, Chiba, Japan
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8
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Using Automated Live Cell Imaging to Reveal Early Changes during Human Motor Neuron Degeneration. eNeuro 2018; 5:eN-MNT-0001-18. [PMID: 29971247 PMCID: PMC6026021 DOI: 10.1523/eneuro.0001-18.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 04/27/2018] [Accepted: 05/12/2018] [Indexed: 01/23/2023] Open
Abstract
Human neurons expressing mutations associated with neurodegenerative disease are becoming more widely available. Hence, developing assays capable of accurately detecting changes that occur early in the disease process and identifying therapeutics able to slow these changes should become ever more important. Using automated live-cell imaging, we studied human motor neurons in the process of dying following neurotrophic factor withdrawal. We tracked different neuronal features, including cell body size, neurite length, and number of nodes. In particular, measuring the number of nodes in individual neurons proved to be an accurate predictor of relative health. Importantly, intermediate phenotypes were defined and could be used to distinguish between agents that could fully restore neurons and neurites and those only capable of maintaining neuronal cell bodies. Application of live-cell imaging to disease modeling has the potential to uncover new classes of therapeutic molecules that intervene early in disease progression.
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Tibshirani M, Zhao B, Gentil BJ, Minotti S, Marques C, Keith J, Rogaeva E, Zinman L, Rouaux C, Robertson J, Durham HD. Dysregulation of chromatin remodelling complexes in amyotrophic lateral sclerosis. Hum Mol Genet 2018; 26:4142-4152. [PMID: 28973294 DOI: 10.1093/hmg/ddx301] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 07/21/2017] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis is a fatal neurodegenerative disease with paralysis resulting from dysfunction and loss of motor neurons. A common neuropathological finding is attrition of motor neuron dendrites, which make central connections vital to motor control. The chromatin remodelling complex, neuronal Brahma-related gene 1 (Brg1)-associated factor complex (nBAF), is critical for neuronal differentiation, dendritic extension and synaptic function. We have identified loss of the crucial nBAF subunits Brg1, Brg1-associated factor 53b and calcium responsive transactivator in cultured motor neurons expressing FUS or TAR-DNA Binding Protein 43 (TDP-43) mutants linked to familial ALS. When plasmids encoding wild-type or mutant human FUS or TDP-43 were expressed in motor neurons of dissociated spinal cord cultures prepared from E13 mice, mutant proteins in particular accumulated in the cytoplasm. Immunolabelling of nBAF subunits was reduced in proportion to loss of nuclear FUS or TDP-43 and depletion of Brg1 was associated with nuclear retention of Brg1 mRNA. Dendritic attrition (loss of intermediate and terminal dendritic branches) occurred in motor neurons expressing mutant, but not wild-type, FUS or TDP-43. This attrition was delayed by ectopic over-expression of Brg1 and was reproduced by inhibiting Brg1 activity either through genetic manipulation or treatment with the chemical inhibitor, (E)-1-(2-Hydroxyphenyl)-3-((1R, 4R)-5-(pyridin-2-yl)-2, 5-diazabicyclo[2.2.1]heptan-2-yl)prop-2-en-1-one, demonstrating the importance of Brg1 to maintenance of dendritic architecture. Loss of nBAF subunits was also documented in spinal motor neurons in autopsy tissue from familial amyotrophic sclerosis (chromosome 9 open reading frame 72 with G4C2 nucleotide expansion) and from sporadic cases with no identified mutation, pointing to dysfunction of nBAF chromatin remodelling in multiple forms of ALS.
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Affiliation(s)
- Michael Tibshirani
- Department of Neurology and Neurosurgery and the Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B3, Canada
| | - Beibei Zhao
- Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, ON M5T 2S8, Canada
| | - Benoit J Gentil
- Department of Neurology and Neurosurgery and the Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B3, Canada
| | - Sandra Minotti
- Department of Neurology and Neurosurgery and the Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B3, Canada
| | - Christine Marques
- Inserm U1118, Faculté de Médecine, Université de Strasbourg, 67 085 Strasbourg Cedex, France
| | - Julia Keith
- Department of Laboratory Medicine and Pathobiology, Sunnybrook Health Sciences Center, University of Toronto, Toronto, ON M4N 3M5, Canada
| | - Ekaterina Rogaeva
- Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, ON M5T 2S8, Canada
| | - Lorne Zinman
- Department of Laboratory Medicine and Pathobiology, Sunnybrook Health Sciences Center, University of Toronto, Toronto, ON M4N 3M5, Canada
| | - Caroline Rouaux
- Inserm U1118, Faculté de Médecine, Université de Strasbourg, 67 085 Strasbourg Cedex, France
| | - Janice Robertson
- Tanz Centre for Research in Neurodegenerative Disease, University of Toronto, Toronto, ON M5T 2S8, Canada.,Department of Laboratory Medicine and Pathobiology, Sunnybrook Health Sciences Center, University of Toronto, Toronto, ON M4N 3M5, Canada
| | - Heather D Durham
- Department of Neurology and Neurosurgery and the Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B3, Canada
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Uematsu M, Nakamura A, Ebashi M, Hirokawa K, Takahashi R, Uchihara T. Brainstem tau pathology in Alzheimer's disease is characterized by increase of three repeat tau and independent of amyloid β. Acta Neuropathol Commun 2018; 6:1. [PMID: 29298724 PMCID: PMC5753447 DOI: 10.1186/s40478-017-0501-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 11/29/2017] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Alzheimer-type neuropil threads (NTs) and neurofibrillary tangles (NFTs) are comprised of either 4 repeat (4R)-tau, 3 repeat (3R)-tau, or a mixture of both. In the hippocampus, the number of NFTs, and the proportion of 3R tau progressively increases. If this preferential accumulation of 3R tau also occurs in the brainstem, it may be fundamentally related to progression of Alzheimer pathology. METHODS Midbrain and pontine sections of brainstems from 23 cases (Braak-NFT stages I/II: 8, III/IV: 8, and V/VI: 7) were double immunofluorolabeled for 4R and 3R tau. High-resolution (0.645 μm/pixel), in-focus snapshots were tiled to cover entire brain sections using a virtual slide system. Each lesion was classified by size (NT < 200 μm2 < NFT) and staining profile (3R/4R). In addition, the localization and quantity of amyloid β (Aβ) deposits were examined in adjacent sections for comparison with tau. RESULTS The data sets obtained from approximately 286 gigabytes of image files consisted of 847,763 NTs and 7859 NFTs. The proportion of 3R tau-positive NTs and NFTs in the midbrain, and 3R tau-positive NTs in the pons gradually increased with advancing NFT stages, while the proportion of 3R tau-positive NFTs in the pons was already elevated at early stages. Aβ deposits were absent at NFT stages I/II, and when present at later stages, their regional distribution was different from that of tau. These observations suggest that a progressive increase in the proportion of 3R tau occurs independently of Aβ deposits. CONCLUSIONS This is the first quantitative analysis of NFTs and NTs in the human brainstem. We demonstrate that the proportion of 3R tau in the brainstem neurofibrillary changes increases with disease progression. Because this phenomenon is shared between the brainstem and the hippocampus, this increase may be fundamental to the pathogenesis of Alzheimer disease.
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11
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Fogarty MJ, Mu EWH, Lavidis NA, Noakes PG, Bellingham MC. Motor Areas Show Altered Dendritic Structure in an Amyotrophic Lateral Sclerosis Mouse Model. Front Neurosci 2017; 11:609. [PMID: 29163013 PMCID: PMC5672020 DOI: 10.3389/fnins.2017.00609] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/18/2017] [Indexed: 12/11/2022] Open
Abstract
Objective: Motor neurons (MNs) die in amyotrophic lateral sclerosis (ALS), a clinically heterogeneous neurodegenerative disease of unknown etiology. In human or rodent studies, MN loss is preceded by increased excitability. As increased neuronal excitability correlates with structural changes in dendritic arbors and spines, we have examined longitudinal changes in dendritic structure in vulnerable neuron populations in a mouse model of familial ALS. Methods: We used a modified Golgi-Cox staining method to determine the progressive changes in dendritic structure of hippocampal CA1 pyramidal neurons, striatal medium spiny neurons, and resistant (trochlear, IV) or susceptible (hypoglossal, XII; lumbar) MNs from brainstem and spinal cord of mice over-expressing the human SOD1G93A (SOD1) mutation, in comparison to wild-type (WT) mice, at four postnatal (P) ages of 8–15, 28–35, 65–75, and 120 days. Results: In SOD1 mice, dendritic changes occur at pre-symptomatic ages in both XII and spinal cord lumbar MNs. Spine loss without dendritic changes was present in striatal neurons from disease onset. Spine density increases were present at all ages studied in SOD1 XII MNs. Spine density increased in neonatal lumbar MNs, before decreasing to control levels by P28-35 and was decreased by P120. SOD1 XII MNs and lumbar MNs, but not trochlear MNs showed vacuolization from the same time-points. Trochlear MN dendrites were unchanged. Interpretation: Dendritic structure and spine alterations correlate with the neuro-motor phenotype in ALS and with cognitive and extra-motor symptoms seen in patients. Prominent early changes in dendritic arbors and spines occur in susceptible cranial and spinal cord MNs, but are absent in MNs resistant to loss in ALS.
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Affiliation(s)
- Matthew J Fogarty
- Faculty of Medicine, School of Biomedical Sciences, University of Queensland, St Lucia, QLD, Australia
| | - Erica W H Mu
- Faculty of Medicine, School of Biomedical Sciences, University of Queensland, St Lucia, QLD, Australia
| | - Nickolas A Lavidis
- Faculty of Medicine, School of Biomedical Sciences, University of Queensland, St Lucia, QLD, Australia
| | - Peter G Noakes
- Faculty of Medicine, School of Biomedical Sciences, University of Queensland, St Lucia, QLD, Australia.,Queensland Brain Institute, University of Queensland, St Lucia, QLD, Australia
| | - Mark C Bellingham
- Faculty of Medicine, School of Biomedical Sciences, University of Queensland, St Lucia, QLD, Australia
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Gentil BJ, Tibshirani M, Durham HD. Neurofilament dynamics and involvement in neurological disorders. Cell Tissue Res 2015; 360:609-20. [PMID: 25567110 DOI: 10.1007/s00441-014-2082-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 11/19/2014] [Indexed: 12/21/2022]
Abstract
Neurons are extremely polarised cells in which the cytoskeleton, composed of microtubules, microfilaments and neurofilaments, plays a crucial role in maintaining structure and function. Neurofilaments, the 10-nm intermediate filaments of neurons, provide structure and mechanoresistance but also provide a scaffolding for the organization of the nucleus and organelles such as mitochondria and ER. Disruption of neurofilament organization and expression or metabolism of neurofilament proteins is characteristic of certain neurological syndromes including Amyotrophic Lateral Sclerosis, Charcot-Marie-Tooth sensorimotor neuropathies and Giant Axonal Neuropathy. Microfluorometric live imaging techniques have been instrumental in revealing the dynamics of neurofilament assembly and transport and their functions in organizing intracellular organelle networks. The insolubility of neurofilament proteins has limited identifying interactors by conventional biochemical techniques but yeast two-hybrid experiments have revealed new roles for oligomeric, nonfilamentous structures including vesicular trafficking. Although having long half-lives, new evidence points to degradation of subunits by the ubiquitin-proteasome system as a mechanism of normal turnover. Although certain E3-ligases ubiquitinating neurofilament proteins have been identified, the overall process of neurofilament degradation is not well understood. We review these mechanisms of neurofilament homeostasis and abnormalities in motor neuron and peripheral nerve disorders. Much remains to discover about the disruption of processes that leads to their pathological aggregation and accumulation and the relevance to pathogenesis. Understanding these mechanisms is crucial for identifying novel therapeutic strategies.
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Affiliation(s)
- Benoit J Gentil
- Department of Neurology/Neurosurgery and Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada,
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TDP-43 pathology and neuronal loss in amyotrophic lateral sclerosis spinal cord. Acta Neuropathol 2014; 128:423-37. [PMID: 24916269 DOI: 10.1007/s00401-014-1299-6] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 05/20/2014] [Accepted: 05/20/2014] [Indexed: 12/27/2022]
Abstract
We examined the phosphorylated 43-kDa TAR DNA-binding protein (pTDP-43) inclusions as well as neuronal loss in full-length spinal cords and five selected regions of the central nervous system from 36 patients with amyotrophic lateral sclerosis (ALS) and 10 age-matched normal controls. The most severe neuronal loss and pTDP-43 lesions were seen in lamina IX motor nuclei columns 4, 6, and 8 of lower cervical segments and in columns 9-11 of lumbosacral segments. Severity of pTDP-43 pathology and neuronal loss correlated closely with gray and white matter oligodendroglial involvement and was linked to onset of disease, with severe involvement of columns 4, 6, and 8 of upper extremity onset cases and severe involvement of columns of 9, 10, and 11 in cases with lower extremity onset. Severe TDP-43 lesions and neuronal loss were observed in stage 4 cases and sometimes included Onuf's nucleus. Notably, three cases displayed pTDP-43 aggregates in the midbrain oculomotor nucleus, which we had not seen previously even in cases with advanced (i.e., stage 4) pathology. pTDP-43 aggregates were observed in neurons of Clarke's column in 30.6 % of cases but rarely in the intermediolateral nucleus (IML). Gray matter oligodendroglial pTDP-43 inclusions were present in areas devoid of neuronal pTDP-43 aggregates and neuronal loss. Taken together, our findings indicate that (1) the dorsolateral motor nuclei columns of the cervical and lumbosacral anterior horn may be the earliest foci of pTDP-43 pathology in the spinal cord, (2) gray matter oligodendroglial involvement is an early event in the ALS disease process that possibly heralds subsequent involvement of neurons by pTDP-43 pathology, and (3) in some very advanced cases, there is oculomotor nucleus involvement, which may constitute an additional neuropathological stage (designated here as stage 5) of pTDP-43 pathology in ALS.
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