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Herrando-Grabulosa M, Gaja-Capdevila N, Vela JM, Navarro X. Sigma 1 receptor as a therapeutic target for amyotrophic lateral sclerosis. Br J Pharmacol 2020; 178:1336-1352. [PMID: 32761823 DOI: 10.1111/bph.15224] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/13/2020] [Accepted: 07/25/2020] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an adult disease causing a progressive loss of upper and lower motoneurons, muscle paralysis and early death. ALS has a poor prognosis of 3-5 years after diagnosis with no effective cure. The aetiopathogenic mechanisms involved include glutamate excitotoxicity, oxidative stress, protein misfolding, mitochondrial alterations, disrupted axonal transport and inflammation. Sigma non-opioid intracellular receptor 1 (sigma 1 receptor) is a protein expressed in motoneurons, mainly found in the endoplasmic reticulum (ER) on the mitochondria-associated ER membrane (MAM) or in close contact with cholinergic postsynaptic sites. MAMs are sites that allow the assembly of several complexes implicated in essential survival cell functions. The sigma 1 receptor modulates essential mechanisms for motoneuron survival including excitotoxicity, calcium homeostasis, ER stress and mitochondrial dysfunction. This review updates sigma 1 receptor mechanisms and its alterations in ALS, focusing on MAM modulation, which may constitute a novel target for therapeutic strategies. LINKED ARTICLES: This article is part of a themed issue on Neurochemistry in Japan. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.6/issuetoc.
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Affiliation(s)
- Mireia Herrando-Grabulosa
- Institute of Neurosciences, Department Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Núria Gaja-Capdevila
- Institute of Neurosciences, Department Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - José M Vela
- Esteve Pharmaceuticals S.A., Drug Discovery and Preclinical Development, Barcelona, Spain
| | - Xavier Navarro
- Institute of Neurosciences, Department Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Institut Guttmann de Neurorehabilitació, Badalona, Spain
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52
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Suk TR, Rousseaux MWC. The role of TDP-43 mislocalization in amyotrophic lateral sclerosis. Mol Neurodegener 2020; 15:45. [PMID: 32799899 PMCID: PMC7429473 DOI: 10.1186/s13024-020-00397-1] [Citation(s) in RCA: 165] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/07/2020] [Indexed: 02/07/2023] Open
Abstract
Since its discovery as a primary component in cytoplasmic aggregates in post-mortem tissue of patients with Amyotrophic Lateral Sclerosis (ALS), TAR DNA Binding Protein 43 kDa (TDP-43) has remained a central focus to understand the disease. TDP-43 links both familial and sporadic forms of ALS as mutations are causative for disease and cytoplasmic aggregates are a hallmark of nearly all cases, regardless of TDP-43 mutational status. Research has focused on the formation and consequences of cytosolic protein aggregates as drivers of ALS pathology through both gain- and loss-of-function mechanisms. Not only does aggregation sequester the normal function of TDP-43, but these aggregates also actively block normal cellular processes inevitably leading to cellular demise in a short time span. Although there may be some benefit to therapeutically targeting TDP-43 aggregation, this step may be too late in disease development to have substantial therapeutic benefit. However, TDP-43 pathology appears to be tightly linked with its mislocalization from the nucleus to the cytoplasm, making it difficult to decouple the consequences of nuclear-to-cytoplasmic mislocalization from protein aggregation. Studies focusing on the effects of TDP-43 mislocalization have demonstrated both gain- and loss-of-function consequences including altered splicing regulation, over responsiveness to cellular stressors, increases in DNA damage, and transcriptome-wide changes. Additionally, mutations in TARDBP confer a baseline increase in cytoplasmic TDP-43 thus suggesting that small changes in the subcellular localization of TDP-43 could in fact drive early pathology. In this review, we bring forth the theme of protein mislocalization as a key mechanism underlying ALS, by highlighting the importance of maintaining subcellular proteostasis along with the gain- and loss-of-functional consequences when TDP-43 localization is dysregulated. Additional research, focusing on early events in TDP-43 pathogenesis (i.e. to the protein mislocalization stage) will provide insight into disease mechanisms, therapeutic targets, and novel biomarkers for ALS.
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Affiliation(s)
- Terry R. Suk
- University of Ottawa Brain and Mind Research Institute, Ottawa, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Maxime W. C. Rousseaux
- University of Ottawa Brain and Mind Research Institute, Ottawa, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- Eric Poulin Center for Neuromuscular Diseases, Ottawa, Canada
- Ottawa Institute of Systems Biology, Ottawa, Canada
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Wang Y, Liu Y, Nham A, Sherbaf A, Quach D, Yahya E, Ranburger D, Bi X, Baudry M. Calpain-2 as a therapeutic target in repeated concussion-induced neuropathy and behavioral impairment. SCIENCE ADVANCES 2020; 6:6/27/eaba5547. [PMID: 32937436 PMCID: PMC7458466 DOI: 10.1126/sciadv.aba5547] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
Repeated concussion represents a serious health problem as it can result in various brain pathologies, ranging from minor focal tissue injury to severe chronic traumatic encephalopathy. The calcium-dependent protease, calpain, participates in the development of neurodegeneration following concussion, but there is no information regarding the relative contribution of calpain-1 and calpain-2, the major calpain isoforms in the brain. We used a mouse model of repeated concussions, which reproduces most of the behavioral and neuropathological features of the human condition, to address this issue. Deletion of calpain-2 or treatment with a selective calpain-2 inhibitor for 2 weeks prevented most of these neuropathological features. Changes in TAR DNA binding protein 43 (TDP-43) subcellular localization similar to those found in human amyotrophic lateral sclerosis and frontotemporal dementia were also prevented by deletion of calpain-2 or treatment with calpain-2 inhibitor. Our results indicate that a selective calpain-2 inhibitor represents a therapeutic approach for concussion.
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Affiliation(s)
- Yubin Wang
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Yan Liu
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Amy Nham
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Arash Sherbaf
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Diana Quach
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Emad Yahya
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Davis Ranburger
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Xiaoning Bi
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, USA
| | - Michel Baudry
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA.
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Pham J, Keon M, Brennan S, Saksena N. Connecting RNA-Modifying Similarities of TDP-43, FUS, and SOD1 with MicroRNA Dysregulation Amidst A Renewed Network Perspective of Amyotrophic Lateral Sclerosis Proteinopathy. Int J Mol Sci 2020; 21:ijms21103464. [PMID: 32422969 PMCID: PMC7278980 DOI: 10.3390/ijms21103464] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 05/10/2020] [Accepted: 05/11/2020] [Indexed: 12/11/2022] Open
Abstract
Beyond traditional approaches in understanding amyotrophic lateral sclerosis (ALS), multiple recent studies in RNA-binding proteins (RBPs)-including transactive response DNA-binding protein (TDP-43) and fused in sarcoma (FUS)-have instigated an interest in their function and prion-like properties. Given their prominence as hallmarks of a highly heterogeneous disease, this prompts a re-examination of the specific functional interrelationships between these proteins, especially as pathological SOD1-a non-RBP commonly associated with familial ALS (fALS)-exhibits similar properties to these RBPs including potential RNA-regulatory capabilities. Moreover, the cytoplasmic mislocalization, aggregation, and co-aggregation of TDP-43, FUS, and SOD1 can be identified as proteinopathies akin to other neurodegenerative diseases (NDs), eliciting strong ties to disrupted RNA splicing, transport, and stability. In recent years, microRNAs (miRNAs) have also been increasingly implicated in the disease, and are of greater significance as they are the master regulators of RNA metabolism in disease pathology. However, little is known about the role of these proteins and how they are regulated by miRNA, which would provide mechanistic insights into ALS pathogenesis. This review seeks to discuss current developments across TDP-43, FUS, and SOD1 to build a detailed snapshot of the network pathophysiology underlying ALS while aiming to highlight possible novel therapeutic targets to guide future research.
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Affiliation(s)
- Jade Pham
- Faculty of Medicine, The University of New South Wales, Kensington, Sydney, NSW 2033, Australia;
| | - Matt Keon
- Iggy Get Out, Neurodegenerative Disease Section, Darlinghurst, Sydney, NSW 2010, Australia; (M.K.); (S.B.)
| | - Samuel Brennan
- Iggy Get Out, Neurodegenerative Disease Section, Darlinghurst, Sydney, NSW 2010, Australia; (M.K.); (S.B.)
| | - Nitin Saksena
- Iggy Get Out, Neurodegenerative Disease Section, Darlinghurst, Sydney, NSW 2010, Australia; (M.K.); (S.B.)
- Correspondence:
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Weskamp K, Tank EM, Miguez R, McBride JP, Gómez NB, White M, Lin Z, Gonzalez CM, Serio A, Sreedharan J, Barmada SJ. Shortened TDP43 isoforms upregulated by neuronal hyperactivity drive TDP43 pathology in ALS. J Clin Invest 2020; 130:1139-1155. [PMID: 31714900 PMCID: PMC7269575 DOI: 10.1172/jci130988] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 11/06/2019] [Indexed: 12/13/2022] Open
Abstract
Cortical hyperexcitability and mislocalization of the RNA-binding protein TDP43 are highly conserved features in amyotrophic lateral sclerosis (ALS). Nevertheless, the relationship between these phenomena remains poorly defined. Here, we showed that hyperexcitability recapitulates TDP43 pathology by upregulating shortened TDP43 (sTDP43) splice isoforms. These truncated isoforms accumulated in the cytoplasm and formed insoluble inclusions that sequestered full-length TDP43 via preserved N-terminal interactions. Consistent with these findings, sTDP43 overexpression was toxic to mammalian neurons, suggesting neurodegeneration arising from complementary gain- and loss-of-function mechanisms. In humans and mice, sTDP43 transcripts were enriched in vulnerable motor neurons, and we observed a striking accumulation of sTDP43 within neurons and glia of ALS patients. Collectively, these studies uncover a pathogenic role for alternative TDP43 isoforms in ALS, and implicate sTDP43 as a key contributor to the susceptibility of motor neurons in this disorder.
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Affiliation(s)
| | | | | | - Jonathon P. McBride
- Department of Neurology
- Cellular and Molecular Biology Program, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Nicolás B. Gómez
- Department of Neurology
- Cellular and Molecular Biology Program, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Ziqiang Lin
- Department of Basic and Clinical Neuroscience and
| | - Carmen Moreno Gonzalez
- Centre for Craniofacial and Regenerative Biology, King’s College London, London, United Kingdom
| | - Andrea Serio
- Centre for Craniofacial and Regenerative Biology, King’s College London, London, United Kingdom
| | | | - Sami J. Barmada
- Department of Neurology
- Neuroscience Graduate Program, and
- Cellular and Molecular Biology Program, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
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56
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Zhang Z, Tian Y, Ye K. δ-secretase in neurodegenerative diseases: mechanisms, regulators and therapeutic opportunities. Transl Neurodegener 2020; 9:1. [PMID: 31911834 PMCID: PMC6943888 DOI: 10.1186/s40035-019-0179-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 11/26/2019] [Indexed: 11/10/2022] Open
Abstract
Mammalian asparagine endopeptidase (AEP) is a cysteine protease that cleaves its protein substrates on the C-terminal side of asparagine residues. Converging lines of evidence indicate that AEP may be involved in the pathogenesis of several neurological diseases, including Alzheimer's disease, Parkinson's disease, and frontotemporal dementia. AEP is activated in the aging brain, cleaves amyloid precursor protein (APP) and promotes the production of amyloid-β (Aβ). We renamed AEP to δ-secretase to emphasize its role in APP fragmentation and Aβ production. AEP also cleaves other substrates, such as tau, α-synuclein, SET, and TAR DNA-binding protein 43, generating neurotoxic fragments and disturbing their physiological functions. The activity of δ-secretase is tightly regulated at both the transcriptional and posttranslational levels. Here, we review the recent advances in the role of δ-secretase in neurodegenerative diseases, with a focus on its biochemical properties and the transcriptional and posttranslational regulation of its activity, and discuss the clinical implications of δ-secretase as a diagnostic biomarker and therapeutic target for neurodegenerative diseases.
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Affiliation(s)
- Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060 People’s Republic of China
| | - Ye Tian
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060 People’s Republic of China
| | - Keqiang Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322 USA
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Niida-Kawaguchi M, Kakita A, Noguchi N, Kazama M, Masui K, Kato Y, Yamamoto T, Sawada T, Kitagawa K, Watabe K, Shibata N. Soluble iron accumulation induces microglial glutamate release in the spinal cord of sporadic amyotrophic lateral sclerosis. Neuropathology 2019; 40:152-166. [PMID: 31883180 DOI: 10.1111/neup.12632] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 12/14/2022]
Abstract
Previous studies on sporadic amyotrophic lateral sclerosis (SALS) demonstrated iron accumulation in the spinal cord and increased glutamate concentration in the cerebrospinal fluid. To clarify the relationship between the two phenomena, we first performed quantitative and morphological analyses of substances related to iron and glutamate metabolism using spinal cords obtained at autopsy from 12 SALS patients and 12 age-matched control subjects. Soluble iron content determined by the Ferrozine method as well as ferritin (Ft) and glutaminase C (GLS-C) expression levels on Western blots were significantly higher in the SALS group than in the control group, while ferroportin (FPN) levels on Western blots were significantly reduced in the SALS group as compared to the control group. There was no significant difference in aconitase 1 (ACO1) and tumor necrosis factor-alpha (TNFα)-converting enzyme (TACE) levels on Western blots between the two groups. Immunohistochemically, Ft, ACO1, TACE, TNFα, and GLS-C were proven to be selectively expressed in microglia. Immunoreactivities for FPN and hepcidin were localized in neuronal and glial cells. Based on these observations, it is predicted that soluble iron may stimulate microglial glutamate release. To address this issue, cell culture experiments were carried out on a microglial cell line (BV-2). Treatment of BV-2 cells with ferric ammonium citrate (FAC) brought about significant increases in intracellular soluble iron and Ft expression levels and conditioned medium glutamate and TNFα concentrations. Glutamate concentration was also significantly increased in conditioned media of TNFα-treated BV-2 cells. While the FAC-driven increases in glutamate and TNFα release were completely canceled by pretreatment with ACO1 and TACE inhibitors, respectively, the TNFα-driven increase in glutamate release was completely canceled by GLS-C inhibitor pretreatment. Moreover, treatment of BV-2 cells with hepcidin resulted in a significant reduction in FPN expression levels on Western blots of the intracellular total protein extracts. The present results provide in vivo and in vitro evidence that microglial glutamate release in SALS spinal cords is enhanced by intracellular soluble iron accumulation-induced activation of ACO1 and TACE and by increased extracellular TNFα-stimulated GLS-C upregulation, and suggest a positive feedback mechanism to maintain increased intracellular soluble iron levels, involving TNFα, hepcidin, and FPN.
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Affiliation(s)
- Motoko Niida-Kawaguchi
- Division of Pathological Neuroscience, Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Noriko Noguchi
- Department of Medical Life Systems, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, Japan
| | - Miku Kazama
- Faculty of Medicine, Tokyo Women's Medical University, Tokyo, Japan
| | - Kenta Masui
- Division of Pathological Neuroscience, Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan
| | - Yoichiro Kato
- Division of Pathological Neuroscience, Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan
| | - Tomoko Yamamoto
- Division of Pathological Neuroscience, Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan
| | - Tatsuo Sawada
- Division of Pathological Neuroscience, Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan
| | - Kazuo Kitagawa
- Department of Neurology, Tokyo Women's Medical University, Tokyo, Japan
| | - Kazuhiko Watabe
- Department of Medical Technology, Faculty of Health Sciences, Kyorin University, Mitaka, Japan
| | - Noriyuki Shibata
- Division of Pathological Neuroscience, Department of Pathology, Tokyo Women's Medical University, Tokyo, Japan
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Tam OH, Ostrow LW, Gale Hammell M. Diseases of the nERVous system: retrotransposon activity in neurodegenerative disease. Mob DNA 2019; 10:32. [PMID: 31372185 PMCID: PMC6659213 DOI: 10.1186/s13100-019-0176-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/18/2019] [Indexed: 12/13/2022] Open
Abstract
Transposable Elements (TEs) are mobile genetic elements whose sequences constitute nearly half of the human genome. Each TE copy can be present in hundreds to thousands of locations within the genome, complicating the genetic and genomic studies of these highly repetitive sequences. The recent development of better tools for evaluating TE derived sequences in genomic studies has enabled an increasing appreciation for the contribution of TEs to human development and disease. While some TEs have contributed novel and beneficial host functions, this review will summarize the evidence for detrimental TE activity in neurodegenerative disorders. Much of the evidence for pathogenicity implicates endogenous retroviruses (ERVs), a subset of TEs that entered the genome by retroviral infections of germline cells in our evolutionary ancestors and have since been passed down as a substantial fraction of the human genome. Human specific ERVs (HERVs) represent some of the youngest ERVs in the genome, and thus are presumed to retain greater function and resultant pathogenic potential.
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Affiliation(s)
- Oliver H Tam
- 1Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 USA
| | - Lyle W Ostrow
- 2Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Molly Gale Hammell
- 1Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724 USA
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Nishino K, Watanabe S, Shijie J, Murata Y, Oiwa K, Komine O, Endo F, Tsuiji H, Abe M, Sakimura K, Mishra A, Yamanaka K. Mice deficient in the C-terminal domain of TAR DNA-binding protein 43 develop age-dependent motor dysfunction associated with impaired Notch1-Akt signaling pathway. Acta Neuropathol Commun 2019; 7:118. [PMID: 31345270 PMCID: PMC6657153 DOI: 10.1186/s40478-019-0776-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 07/18/2019] [Indexed: 02/06/2023] Open
Abstract
Intracellular mislocalization of TAR DNA-binding protein 43 (TDP-43), a nuclear DNA/RNA-binding protein involved in RNA metabolism, is a pathological hallmark of amyotrophic lateral sclerosis (ALS). Although the aggregation-prone, TDP-43 C-terminal domain is widely considered as a key component of TDP-43 pathology in ALS, recent studies including ours suggest that TDP-43 N-terminal fragments (TDP-∆C) may also contribute to the motor dysfunction in ALS. However, the specific pathological functions of TDP-43 N-terminal fragments in mice have not been elucidated. Here, we established TDP-∆C knock-in mice missing a part of exon 6 of murine Tardbp gene, which encodes the C-terminal region of TDP-43. Homozygous TDP-∆C mice showed embryonic lethality, indicating that the N-terminal domain of TDP-43 alone is not sufficient for normal development. In contrast, heterozygous TDP-∆C mice developed normally but exhibited age-dependent mild motor dysfunction with a loss of C-boutons, large cholinergic synaptic terminals on spinal α-motor neurons. TDP-∆C protein broadly perturbed gene expression in the spinal cords of aged heterozygous TDP-∆C mice, including downregulation of Notch1 mRNA. Moreover, the level of Notch1 mRNA was suppressed both by TDP-43 depletion and TDP-∆C expression in Neuro2a cells. Decreased Notch1 mRNA expression in aged TDP-∆C mice was associated with the age-dependent motor dysfunction and loss of Akt surviving signal. Our findings indicate that the N-terminal region of TDP-43 derived from TDP-∆C induces the age-dependent motor dysfunction associated with impaired Notch1-Akt axis in mice.
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Affiliation(s)
- Kohei Nishino
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Chikusa-ku, Nagoya, Aichi 464-8601 Japan
- Department of Neuroscience and Pathobiology, Graduate School of Medicine, Nagoya University, Nagoya, Aichi 466-8550 Japan
| | - Seiji Watanabe
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Chikusa-ku, Nagoya, Aichi 464-8601 Japan
- Department of Neuroscience and Pathobiology, Graduate School of Medicine, Nagoya University, Nagoya, Aichi 466-8550 Japan
| | - Jin Shijie
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Chikusa-ku, Nagoya, Aichi 464-8601 Japan
- Department of Neuroscience and Pathobiology, Graduate School of Medicine, Nagoya University, Nagoya, Aichi 466-8550 Japan
| | - Yuri Murata
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Chikusa-ku, Nagoya, Aichi 464-8601 Japan
- Department of Neuroscience and Pathobiology, Graduate School of Medicine, Nagoya University, Nagoya, Aichi 466-8550 Japan
| | - Kotaro Oiwa
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Chikusa-ku, Nagoya, Aichi 464-8601 Japan
- Department of Neuroscience and Pathobiology, Graduate School of Medicine, Nagoya University, Nagoya, Aichi 466-8550 Japan
| | - Okiru Komine
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Chikusa-ku, Nagoya, Aichi 464-8601 Japan
- Department of Neuroscience and Pathobiology, Graduate School of Medicine, Nagoya University, Nagoya, Aichi 466-8550 Japan
| | - Fumito Endo
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Chikusa-ku, Nagoya, Aichi 464-8601 Japan
- Department of Neuroscience and Pathobiology, Graduate School of Medicine, Nagoya University, Nagoya, Aichi 466-8550 Japan
| | - Hitomi Tsuiji
- Department of Biomedical Science, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi 467-8603 Japan
| | - Manabu Abe
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, 951-8585 Japan
| | - Kenji Sakimura
- Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, 951-8585 Japan
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan 342011 India
| | - Koji Yamanaka
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Chikusa-ku, Nagoya, Aichi 464-8601 Japan
- Department of Neuroscience and Pathobiology, Graduate School of Medicine, Nagoya University, Nagoya, Aichi 466-8550 Japan
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60
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Extracellular RNAs as Biomarkers of Sporadic Amyotrophic Lateral Sclerosis and Other Neurodegenerative Diseases. Int J Mol Sci 2019; 20:ijms20133148. [PMID: 31252669 PMCID: PMC6651127 DOI: 10.3390/ijms20133148] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 06/21/2019] [Accepted: 06/26/2019] [Indexed: 12/13/2022] Open
Abstract
Recent progress in the research for underlying mechanisms in neurodegenerative diseases, including Alzheimer disease (AD), Parkinson disease (PD), and amyotrophic lateral sclerosis (ALS) has led to the development of potentially effective treatment, and hence increased the need for useful biomarkers that may enable early diagnosis and therapeutic monitoring. The deposition of abnormal proteins is a pathological hallmark of neurodegenerative diseases, including β-amyloid in AD, α-synuclein in PD, and the transactive response DNA/RNA binding protein of 43kDa (TDP-43) in ALS. Furthermore, progression of the disease process accompanies the spreading of abnormal proteins. Extracellular proteins and RNAs, including mRNA, micro RNA, and circular RNA, which are present as a composite of exosomes or other forms, play a role in cell–cell communication, and the role of extracellular molecules in the cell-to-cell spreading of pathological processes in neurodegenerative diseases is now in the spotlight. Therefore, extracellular proteins and RNAs are considered potential biomarkers of neurodegenerative diseases, in particular ALS, in which RNA dysregulation has been shown to be involved in the pathogenesis. Here, we review extracellular proteins and RNAs that have been scrutinized as potential biomarkers of neurodegenerative diseases, and discuss the possibility of extracellular RNAs as diagnostic and therapeutic monitoring biomarkers of sporadic ALS.
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61
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Ragagnin AMG, Shadfar S, Vidal M, Jamali MS, Atkin JD. Motor Neuron Susceptibility in ALS/FTD. Front Neurosci 2019; 13:532. [PMID: 31316328 PMCID: PMC6610326 DOI: 10.3389/fnins.2019.00532] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 05/08/2019] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the death of both upper and lower motor neurons (MNs) in the brain, brainstem and spinal cord. The neurodegenerative mechanisms leading to MN loss in ALS are not fully understood. Importantly, the reasons why MNs are specifically targeted in this disorder are unclear, when the proteins associated genetically or pathologically with ALS are expressed ubiquitously. Furthermore, MNs themselves are not affected equally; specific MNs subpopulations are more susceptible than others in both animal models and human patients. Corticospinal MNs and lower somatic MNs, which innervate voluntary muscles, degenerate more readily than specific subgroups of lower MNs, which remain resistant to degeneration, reflecting the clinical manifestations of ALS. In this review, we discuss the possible factors intrinsic to MNs that render them uniquely susceptible to neurodegeneration in ALS. We also speculate why some MN subpopulations are more vulnerable than others, focusing on both their molecular and physiological properties. Finally, we review the anatomical network and neuronal microenvironment as determinants of MN subtype vulnerability and hence the progression of ALS.
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Affiliation(s)
- Audrey M G Ragagnin
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Sina Shadfar
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Marta Vidal
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Md Shafi Jamali
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Julie D Atkin
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
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Gentile F, Scarlino S, Falzone YM, Lunetta C, Tremolizzo L, Quattrini A, Riva N. The Peripheral Nervous System in Amyotrophic Lateral Sclerosis: Opportunities for Translational Research. Front Neurosci 2019; 13:601. [PMID: 31293369 PMCID: PMC6603245 DOI: 10.3389/fnins.2019.00601] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/27/2019] [Indexed: 12/11/2022] Open
Abstract
Although amyotrophic lateral sclerosis (ALS) has been considered as a disorder of the motor neuron (MN) cell body, recent evidences show the non-cell-autonomous pathogenic nature of the disease. Axonal degeneration, loss of peripheral axons and destruction of nerve terminals are early events in the disease pathogenic cascade, anticipating MN degeneration, and the onset of clinical symptoms. Therefore, although ALS and peripheral axonal neuropathies should be differentiated in clinical practice, they also share damage to common molecular pathways, including axonal transport, RNA metabolism and proteostasis. Thus, an extensive evaluation of the molecular events occurring in the peripheral nervous system (PNS) could be fundamental to understand the pathogenic mechanisms of ALS, favoring the discovery of potential disease biomarkers, and new therapeutic targets.
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Affiliation(s)
- Francesco Gentile
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology - San Raffaele Scientific Institute, Milan, Italy
| | - Stefania Scarlino
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology - San Raffaele Scientific Institute, Milan, Italy
| | - Yuri Matteo Falzone
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology - San Raffaele Scientific Institute, Milan, Italy.,Department of Neurology, San Raffaele Scientific Institute, Milan, Italy
| | | | - Lucio Tremolizzo
- Neurology Unit, ALS Clinic, San Gerardo Hospital, University of Milano-Bicocca, Monza, Italy
| | - Angelo Quattrini
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology - San Raffaele Scientific Institute, Milan, Italy
| | - Nilo Riva
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology - San Raffaele Scientific Institute, Milan, Italy.,Department of Neurology, San Raffaele Scientific Institute, Milan, Italy
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63
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Liu CH, Rasband MN. Axonal Spectrins: Nanoscale Organization, Functional Domains and Spectrinopathies. Front Cell Neurosci 2019; 13:234. [PMID: 31191255 PMCID: PMC6546920 DOI: 10.3389/fncel.2019.00234] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 05/09/2019] [Indexed: 11/13/2022] Open
Abstract
Spectrin cytoskeletons are found in all metazoan cells, and their physical interactions between actin and ankyrins establish a meshwork that provides cellular structural integrity. With advanced super-resolution microscopy, the intricate spatial organization and associated functional properties of these cytoskeletons can now be analyzed with unprecedented clarity. Long neuronal processes like peripheral sensory and motor axons may be subject to intense mechanical forces including bending, stretching, and torsion. The spectrin-based cytoskeleton is essential to protect axons against these mechanical stresses. Additionally, spectrins are critical for the assembly and maintenance of axonal excitable domains including the axon initial segment and the nodes of Ranvier (NoR). These sites facilitate rapid and efficient action potential initiation and propagation in the nervous system. Recent studies revealed that pathogenic spectrin variants and diseases that protealyze and breakdown spectrins are associated with congenital neurological disorders and nervous system injury. Here, we review recent studies of spectrins in the nervous system and focus on their functions in axonal health and disease.
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Affiliation(s)
- Cheng-Hsin Liu
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States
| | - Matthew Neil Rasband
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
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64
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TDP-43 induces mitochondrial damage and activates the mitochondrial unfolded protein response. PLoS Genet 2019; 15:e1007947. [PMID: 31100073 PMCID: PMC6524796 DOI: 10.1371/journal.pgen.1007947] [Citation(s) in RCA: 144] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 01/08/2019] [Indexed: 02/07/2023] Open
Abstract
Mutations in or dys-regulation of the TDP-43 gene have been associated with TDP-43 proteinopathy, a spectrum of neurodegenerative diseases including Frontotemporal Lobar Degeneration (FTLD) and Amyotrophic Lateral Sclerosis (ALS). The underlying molecular and cellular defects, however, remain unclear. Here, we report a systematic study combining analyses of patient brain samples with cellular and animal models for TDP-43 proteinopathy. Electron microscopy (EM) analyses of patient samples revealed prominent mitochondrial impairment, including abnormal cristae and a loss of cristae; these ultrastructural changes were consistently observed in both cellular and animal models of TDP-43 proteinopathy. In these models, increased TDP-43 expression induced mitochondrial dysfunction, including decreased mitochondrial membrane potential and elevated production of reactive oxygen species (ROS). TDP-43 expression suppressed mitochondrial complex I activity and reduced mitochondrial ATP synthesis. Importantly, TDP-43 activated the mitochondrial unfolded protein response (UPRmt) in both cellular and animal models. Down-regulating mitochondrial protease LonP1 increased mitochondrial TDP-43 levels and exacerbated TDP-43-induced mitochondrial damage as well as neurodegeneration. Together, our results demonstrate that TDP-43 induced mitochondrial impairment is a critical aspect in TDP-43 proteinopathy. Our work has not only uncovered a previously unknown role of LonP1 in regulating mitochondrial TDP-43 levels, but also advanced our understanding of the pathogenic mechanisms for TDP-43 proteinopathy. Our study suggests that blocking or reversing mitochondrial damage may provide a potential therapeutic approach to these devastating diseases. TDP-43 proteinopathy is a group of fatal neurological diseases. Here, we report a systematic examination of the role of mitochondrial damage in TDP-43 proteinopathy using patient brain tissues, as well as cellular and animal models. Our data show that TDP-43 induces severe mitochondrial damage, accompanied by activation of UPRmt in both cellular and animal models of TDP-43 proteinopathy. LonP1, one of the key mitochondrial proteases in UPRmt, protects against TDP-43 induced cytotoxicity and neurodegeneration. Our study uncovers LonP1 as a modifier gene for TDP-43 proteinopathy and suggests protecting against or reversing mitochondrial damage as a potential therapeutic approach to these neurodegenerative disorders.
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65
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Berning BA, Walker AK. The Pathobiology of TDP-43 C-Terminal Fragments in ALS and FTLD. Front Neurosci 2019; 13:335. [PMID: 31031584 PMCID: PMC6470282 DOI: 10.3389/fnins.2019.00335] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/22/2019] [Indexed: 12/11/2022] Open
Abstract
During neurodegenerative disease, the multifunctional RNA-binding protein TDP-43 undergoes a vast array of post-translational modifications, including phosphorylation, acetylation, and cleavage. Many of these alterations may directly contribute to the pathogenesis of TDP-43 proteinopathies, which include most forms of amyotrophic lateral sclerosis (ALS) and approximately half of all frontotemporal dementia, pathologically identified as frontotemporal lobar degeneration (FTLD) with TDP-43 pathology. However, the relative contributions of the various TDP-43 post-translational modifications to disease remain unclear, and indeed some may be secondary epiphenomena rather than disease-causative. It is therefore critical to determine the involvement of each modification in disease processes to allow the design of targeted treatments. In particular, TDP-43 C-terminal fragments (CTFs) accumulate in the brains of people with ALS and FTLD and are therefore described as a neuropathological signature of these diseases. Remarkably, these TDP-43 CTFs are rarely observed in the spinal cord, even in ALS which involves dramatic degeneration of spinal motor neurons. Therefore, TDP-43 CTFs are not produced non-specifically in the course of all forms of TDP-43-related neurodegeneration, but rather variably arise due to additional factors influenced by regional heterogeneity in the central nervous system. In this review, we summarize how TDP-43 CTFs are generated and degraded by cells, and critique evidence from studies of TDP-43 CTF pathology in human disease tissues, as well as cell and animal models, to analyze the pathophysiological relevance of TDP-43 CTFs to ALS and FTLD. Numerous studies now indicate that, although TDP-43 CTFs are prevalent in ALS and FTLD brains, disease-related pathology is only variably reproduced in TDP-43 CTF cell culture models. Furthermore, TDP-43 CTF expression in both transgenic and viral-mediated in vivo models largely fails to induce motor or behavioral dysfunction reminiscent of human disease. We therefore conclude that although TDP-43 CTFs are a hallmark of TDP-43-related neurodegeneration in the brain, they are not a primary cause of ALS or FTLD.
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Affiliation(s)
- Britt A. Berning
- Neurodegeneration Pathobiology Laboratory, Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia
| | - Adam K. Walker
- Neurodegeneration Pathobiology Laboratory, Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, North Ryde, NSW, Australia
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CREDO: Highly confident disease-relevant A-to-I RNA-editing discovery in breast cancer. Sci Rep 2019; 9:5064. [PMID: 30911020 PMCID: PMC6433923 DOI: 10.1038/s41598-019-41294-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 02/25/2019] [Indexed: 12/19/2022] Open
Abstract
Adenosine-to-Inosine (A-to-I) RNA editing is the most prevalent post-transcriptional modification of RNA molecules. Researchers have attempted to find reliable RNA editing using next generation sequencing (NGS) data. However, most of these attempts suffered from a high rate of false positives, and they did not consider the clinical relevance of the identified RNA editing, for example, in disease progression. We devised an effective RNA-editing discovery pipeline called CREDO, which includes novel statistical filtering modules based on integration of DNA- and RNA-seq data from matched tumor-normal tissues. CREDO was compared with three other RNA-editing discovery pipelines and found to give significantly fewer false positives. Application of CREDO to breast cancer data from the Cancer Genome Atlas (TCGA) project discovered highly confident RNA editing with clinical relevance to cancer progression in terms of patient survival. RNA-editing detection using DNA- and RNA-seq data from matched tumor-normal tissues should be more routinely performed as multiple omics data are becoming commonly available from each patient sample. We believe CREDO is an effective and reliable tool for this problem.
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Sinigaglia K, Wiatrek D, Khan A, Michalik D, Sambrani N, Sedmík J, Vukić D, O'Connell MA, Keegan LP. ADAR RNA editing in innate immune response phasing, in circadian clocks and in sleep. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:356-369. [DOI: 10.1016/j.bbagrm.2018.10.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 10/12/2018] [Accepted: 10/27/2018] [Indexed: 01/24/2023]
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Prasad A, Bharathi V, Sivalingam V, Girdhar A, Patel BK. Molecular Mechanisms of TDP-43 Misfolding and Pathology in Amyotrophic Lateral Sclerosis. Front Mol Neurosci 2019; 12:25. [PMID: 30837838 PMCID: PMC6382748 DOI: 10.3389/fnmol.2019.00025] [Citation(s) in RCA: 402] [Impact Index Per Article: 80.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 01/21/2019] [Indexed: 12/11/2022] Open
Abstract
TAR DNA binding protein 43 (TDP-43) is a versatile RNA/DNA binding protein involved in RNA-related metabolism. Hyper-phosphorylated and ubiquitinated TDP-43 deposits act as inclusion bodies in the brain and spinal cord of patients with the motor neuron diseases: amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). While the majority of ALS cases (90-95%) are sporadic (sALS), among familial ALS cases 5-10% involve the inheritance of mutations in the TARDBP gene and the remaining (90-95%) are due to mutations in other genes such as: C9ORF72, SOD1, FUS, and NEK1 etc. Strikingly however, the majority of sporadic ALS patients (up to 97%) also contain the TDP-43 protein deposited in the neuronal inclusions, which suggests of its pivotal role in the ALS pathology. Thus, unraveling the molecular mechanisms of the TDP-43 pathology seems central to the ALS therapeutics, hence, we comprehensively review the current understanding of the TDP-43's pathology in ALS. We discuss the roles of TDP-43's mutations, its cytoplasmic mis-localization and aberrant post-translational modifications in ALS. Also, we evaluate TDP-43's amyloid-like in vitro aggregation, its physiological vs. pathological oligomerization in vivo, liquid-liquid phase separation (LLPS), and potential prion-like propagation propensity of the TDP-43 inclusions. Finally, we describe the various evolving TDP-43-induced toxicity mechanisms, such as the impairment of endocytosis and mitotoxicity etc. and also discuss the emerging strategies toward TDP-43 disaggregation and ALS therapeutics.
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Affiliation(s)
| | | | | | | | - Basant K. Patel
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Sangareddy, India
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Killing Two Angry Birds with One Stone: Autophagy Activation by Inhibiting Calpains in Neurodegenerative Diseases and Beyond. BIOMED RESEARCH INTERNATIONAL 2019; 2019:4741252. [PMID: 30895192 PMCID: PMC6393885 DOI: 10.1155/2019/4741252] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/27/2019] [Indexed: 12/21/2022]
Abstract
Proteolytic machineries execute vital cellular functions and their disturbances are implicated in diverse medical conditions, including neurodegenerative diseases. Interestingly, calpains, a class of Ca2+-dependent regulatory proteases, can modulate the degradational system of autophagy by cleaving proteins involved in this pathway. Moreover, both machineries are common players in many molecular pathomechanisms and have been targeted individually or together, as a therapeutic strategy in experimental setups. In this review, we briefly introduce calpains and autophagy, with their roles in health and disease, and focus on their direct pathologically relevant interplay in neurodegeneration and beyond. The modulation of calpain activity may comprise a promising treatment approach to attenuate the deregulation of these two essential mechanisms.
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Abstract
Calpains are signaling proteases that have relatively little sequence specificity but some preferences for certain residues on either side of the scissile bond. As with most proteases, they mainly cut unstructured or extended regions of their target proteins. The tendency for concentrated calpain to rapidly autoproteolyze when activated by calcium complicates the kinetic assessment of calpain activity. As calpain autoproteolyzes, the amount of fully active enzyme continuously decreases until all of the calpain molecules have been cut and their activity reduced to a tiny fraction of the starting rate. To accurately measure calpain kinetics, only the initial rate of substrate hydrolysis, where autoproteolysis is minimal, can be used. To accomplish this, a method for rapid, quantifiable determination of substrate cleavage is required. Many of the existing assays are lacking in their sensitivity to accurately quantify calpain activity within this timeframe. However, the FRET peptide substrates developed by Cuerrier et al. have been shown to have sufficiently high affinity between substrate and enzyme to accurately measure the initial enzyme reaction velocity at substrate concentrations above the Km value. With a suitably sensitive fluorimeter, sufficient data can be obtained to evaluate calpain kinetics and inhibition. Here we describe a facile, reliable calpain assay based on the continuous monitoring of FRET fluorescence from the highly sensitive calpain-specific substrate, (EDANS)-EPLFAERK-(DABCYL). We illustrate some difficulties associated with determining kinetic constants of whole calpains that are simultaneously undergoing autoproteolysis and how the assay can be used to help characterize calpain-specific inhibitors. We also present a variation of this fluorescence-based assay for high-throughput screening using the calpain protease core and a fluorescence plate reader.
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Affiliation(s)
| | - Peter L Davies
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
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72
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Aizawa H, Yamashita T, Kato H, Kimura T, Kwak S. Impaired Nucleoporins Are Present in Sporadic Amyotrophic Lateral Sclerosis Motor Neurons that Exhibit Mislocalization of the 43-kDa TAR DNA-Binding Protein. J Clin Neurol 2019; 15:62-67. [PMID: 30618218 PMCID: PMC6325357 DOI: 10.3988/jcn.2019.15.1.62] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/20/2018] [Accepted: 08/23/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE Disruption of nucleoporins has been reported in the motor neurons of patients with sporadic amyotrophic lateral sclerosis (sALS). However, the precise changes in the morphology of nucleoporins associated with the pathology of the 43-kDa TAR DNA-binding protein (TDP-43) in the disease process remain unknown. We investigated the expression of nucleoporins that constitute the nuclear pore complex (NPC) in spinal motor neurons that exhibit sALS in relation to TDP-43 pathology, which is a reliable neuropathological hallmark of sALS. METHODS Paraffin-embedded sections of the lumbar spinal cord were obtained for immunofluorescence analysis from seven control subjects and six sALS patients. Anti-TDP-43 antibody, anti-nucleoporin p62 (NUP62) antibody, and anti-karyopherin beta 1 (KPNB1) antibody were applied as primary antibodies, and then visualized using appropriate secondary antibodies. The sections were then examined under a fluorescence microscope. RESULTS NUP62 and KPNB1 immunoreactivity appeared as a smooth round rim bordering the nuclear margin in normal spinal motor neurons that exhibited nuclear TDP-43 immunoreactivity. sALS spinal motor neurons with apparent TDP-43 mislocalization demonstrated irregular, disrupted nuclear staining for NUP62 or KPNB1. Some atrophic sALS spinal motor neurons with TDP-43 mislocalization presented no NUP62 immunoreactivity. CONCLUSIONS Our findings suggest a close relationship between NPC alterations and TDP-43 pathology in the degenerative process of the motor neurons of sALS patients.
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Affiliation(s)
- Hitoshi Aizawa
- Department of Neurology, Tokyo Medical University, Tokyo, Japan.
| | - Takenari Yamashita
- Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Haruhisa Kato
- Department of Neurology, Tokyo Medical University, Tokyo, Japan
| | - Takashi Kimura
- Department of Neurology, Asahikawa Medical Center, National Hospital Organization, Asahikawa, Japan
| | - Shin Kwak
- Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Hosaka T, Yamashita T, Teramoto S, Hirose N, Tamaoka A, Kwak S. ADAR2-dependent A-to-I RNA editing in the extracellular linear and circular RNAs. Neurosci Res 2018; 147:48-57. [PMID: 30448461 DOI: 10.1016/j.neures.2018.11.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 11/11/2018] [Accepted: 11/13/2018] [Indexed: 12/13/2022]
Abstract
Currently, no reliable biomarkers of amyotrophic lateral sclerosis (ALS) exist. In sporadic ALS, RNA editing at the glutamine/arginine site of GluA2 mRNA is specifically reduced in the motor neurons due to the downregulation of adenosine deaminase acting on RNA 2 (ADAR2). Furthermore, TDP-43 pathology, the pathological hallmark of ALS, is observed in the ADAR2-lacking motor neurons in ALS patients and conditional ADAR2 knockout mice, suggesting a pivotal role of ADAR2 downregulation in the ALS pathogenesis. Extracellular RNAs were shown to represent potential disease biomarkers and the editing efficiencies at their ADAR2-dependent sites may reflect cellular ADAR2 activity, suggesting that these RNAs isolated from the body fluids may represent the biomarkers of ALS. We searched for ADAR2-dependent sites in the mouse motor neurons and human-derived cultured cells and found 10 sites in five host RNAs expressed in SH-SY5Y cells and their culture medium. Of these, the arginine/glycine site of SON mRNA was newly identified as an ADAR2-dependent site. Furthermore, we detected a circular RNA with an ADAR2-dependent site in the SH-SY5Y cells and their culture medium. Therefore, the changes in the editing efficiencies at the identified host RNA sites isolated from the body fluids may represent potential biomarkers of ALS.
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Affiliation(s)
- Takashi Hosaka
- Department of Neurology, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, 305-8575, Japan; Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Takenari Yamashita
- Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan; Department of Pathophysiology, Tokyo Medical University, Tokyo, 160-8402, Japan
| | - Sayaka Teramoto
- Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Naoki Hirose
- Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Akira Tamaoka
- Department of Neurology, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, 305-8575, Japan
| | - Shin Kwak
- Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.
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Steinacker P, Barschke P, Otto M. Biomarkers for diseases with TDP-43 pathology. Mol Cell Neurosci 2018; 97:43-59. [PMID: 30399416 DOI: 10.1016/j.mcn.2018.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 10/26/2018] [Accepted: 10/29/2018] [Indexed: 01/01/2023] Open
Abstract
The discovery that aggregated transactive response DNA-binding protein 43 kDa (TDP-43) is the major component of pathological ubiquitinated inclusions in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) caused seminal progress in the unveiling of the genetic bases and molecular characteristics of these now so-called TDP-43 proteinopathies. Substantial increase in the knowledge of clinic-pathological coherencies, especially for FTLD variants, could be made in the last decade, but also revealed a considerable complexity of TDP-43 pathology and often a poor correlation of clinical and molecular disease characteristics. To date, an underlying TDP-43 pathology can be predicted only for patients with mutations in the genes C9orf72 and GRN, but is dependent on neuropathological verification in patients without family history, which represent the majority of cases. As etiology-specific therapies for neurodegenerative proteinopathies are emerging, methods to forecast TDP-43 pathology at patients' lifetime are highly required. Here, we review the current status of research pursued to identify specific indicators to predict or exclude TDP-43 pathology in the ALS-FTLD spectrum disorders and findings on candidates for prognosis and monitoring of disease progression in TDP-43 proteinopathies with a focus on TDP-43 with its pathological forms, neurochemical and imaging biomarkers.
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Affiliation(s)
| | - Peggy Barschke
- Department of Neurology, University of Ulm, Ulm, Germany
| | - Markus Otto
- Department of Neurology, University of Ulm, Ulm, Germany.
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Kitamura A, Iwasaki N, Kinjo M. Molecular chaperone HSP70 prevents formation of inclusion bodies of the 25-kDa C-terminal fragment of TDP-43 by preventing aggregate accumulation. Cell Stress Chaperones 2018; 23:1177-1183. [PMID: 30099725 PMCID: PMC6237682 DOI: 10.1007/s12192-018-0930-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/08/2018] [Accepted: 05/25/2018] [Indexed: 01/12/2023] Open
Abstract
Transactive response DNA/RNA-binding protein 43-kDa (TDP-43) C-terminal fragments, such as a 25-kDa fragment (TDP-25), have been identified as a ubiquitinated and phosphorylated components of inclusion bodies (IBs) in motor neurons from amyotrophic lateral sclerosis patients. Cells contain proteins that function as molecular chaperones and prevent aggregate formation of misfolded and aggregation-prone proteins. Recently, we reported that heat shock protein (HSP)70, an abundant molecular chaperone, binds to TDP-25 in an ATP-dependent manner; however, whether HSP70 can prevent the formation of TDP-25-related IBs remains unknown. Here, we showed that HSP70 prevented TDP-25 aggregation according to green fluorescent protein-tagged TDP-25 (G-TDP-25) colocalization in the cytoplasm with mCherry-tagged HSP70 (HSP70-R). The mobile fraction of HSP70-R in the cytoplasmic IBs associated with G-TDP-25 increased relative to that of G-TDP-25, suggesting that HSP70 strongly bound to G-TDP-25 in the IBs, whereas a portion remained dissociated from the IBs. Importantly, the proportion of G-TDP-25 IBs was significantly decreased by HSP70-R overexpression; however, G-TDP-25 levels in the insoluble fraction remained unchanged by HSP70-R overexpression, suggesting that G-TDP-25 formed aggregated species that cannot be dissolved, even in the presence of strong detergents. These results indicated that HSP70 prevented the accumulation of G-TDP-25 aggregates in cytoplasmic IBs, but was insufficient for G-TDP-25 disassembly and solubilization.
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Affiliation(s)
- Akira Kitamura
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo, 001-0021, Japan
| | - Nodoka Iwasaki
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo, 001-0021, Japan
| | - Masataka Kinjo
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo, 001-0021, Japan.
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de la Fuente S, Sansa A, Periyakaruppiah A, Garcera A, Soler RM. Calpain Inhibition Increases SMN Protein in Spinal Cord Motoneurons and Ameliorates the Spinal Muscular Atrophy Phenotype in Mice. Mol Neurobiol 2018; 56:4414-4427. [PMID: 30327977 PMCID: PMC6505520 DOI: 10.1007/s12035-018-1379-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/01/2018] [Indexed: 01/07/2023]
Abstract
Spinal muscular atrophy (SMA), a leading genetic cause of infant death, is caused by the loss of survival motor neuron 1 (SMN1) gene. SMA is characterized by the degeneration and loss of spinal cord motoneurons (MNs), muscular atrophy, and weakness. SMN2 is the centromeric duplication of the SMN gene, whose numbers of copies determine the intracellular levels of SMN protein and define the disease onset and severity. It has been demonstrated that elevating SMN levels can be an important strategy in treating SMA and can be achieved by several mechanisms, including promotion of protein stability. SMN protein is a direct target of the calcium-dependent protease calpain and induces its proteolytic cleavage in muscle cells. In this study, we examined the involvement of calpain in SMN regulation on MNs. In vitro experiments showed that calpain activation induces SMN cleavage in CD1 and SMA mouse spinal cord MNs. Additionally, calpain 1 knockdown or inhibition increased SMN level and prevent neurite degeneration in these cells. We examined the effects of calpain inhibition on the phenotype of two severe SMA mouse models. Treatment with the calpain inhibitor, calpeptin, significantly improved the lifespan and motor function of these mice. Our observations show that calpain regulates SMN level in MNs and calpeptin administration improves SMA phenotype demonstrating the potential utility of calpain inhibitors in SMA therapy.
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Affiliation(s)
- Sandra de la Fuente
- Unitat de Senyalització Neuronal, Department Medicina Experimental, Universitat de Lleida-IRBLleida, Rovira Roure 80, 25198, Lleida, Spain
| | - Alba Sansa
- Unitat de Senyalització Neuronal, Department Medicina Experimental, Universitat de Lleida-IRBLleida, Rovira Roure 80, 25198, Lleida, Spain
| | - Ambika Periyakaruppiah
- Unitat de Senyalització Neuronal, Department Medicina Experimental, Universitat de Lleida-IRBLleida, Rovira Roure 80, 25198, Lleida, Spain
| | - Ana Garcera
- Unitat de Senyalització Neuronal, Department Medicina Experimental, Universitat de Lleida-IRBLleida, Rovira Roure 80, 25198, Lleida, Spain
| | - Rosa M Soler
- Unitat de Senyalització Neuronal, Department Medicina Experimental, Universitat de Lleida-IRBLleida, Rovira Roure 80, 25198, Lleida, Spain.
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Gatsiou A, Vlachogiannis N, Lunella FF, Sachse M, Stellos K. Adenosine-to-Inosine RNA Editing in Health and Disease. Antioxid Redox Signal 2018; 29:846-863. [PMID: 28762759 DOI: 10.1089/ars.2017.7295] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
SIGNIFICANCE Adenosine deamination in transcriptome results in the formation of inosine, a process that is called A-to-I RNA editing. Adenosine deamination is one of the more than 140 described RNA modifications. A-to-I RNA editing is catalyzed by adenosine deaminase acting on RNA (ADAR) enzymes and is essential for life. Recent Advances: Accumulating evidence supports a critical role of RNA editing in all aspects of RNA metabolism, including mRNA stability, splicing, nuclear export, and localization, as well as in recoding of proteins. These advances have significantly enhanced the understanding of mechanisms involved in development and in homeostasis. Furthermore, recent studies have indicated that RNA editing may be critically involved in cancer, aging, neurological, autoimmune, or cardiovascular diseases. CRITICAL ISSUES This review summarizes recent and significant achievements in the field of A-to-I RNA editing and discusses the importance and translational value of this RNA modification for gene expression, cellular, and organ function, as well as for disease development. FUTURE DIRECTIONS Elucidation of the exact RNA editing-dependent mechanisms in a single-nucleotide level may pave the path toward the development of novel therapeutic strategies focusing on modulation of ADAR function in the disease context. Antioxid. Redox Signal. 29, 846-863.
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Affiliation(s)
- Aikaterini Gatsiou
- 1 Institute of Cardiovascular Regeneration, Center of Molecular Medicine, JW Goethe University Frankfurt , Frankfurt, Germany .,2 Department of Biosciences, JW Goethe University Frankfurt , Frankfurt, Germany .,3 Department of Cardiology, Center of Internal Medicine, JW Goethe University Frankfurt , Frankfurt, Germany .,4 German Center of Cardiovascular Research (DZHK) , Rhein-Main Partner Site, Frankfurt, Germany
| | - Nikolaos Vlachogiannis
- 5 Rheumatology Unit, First Department of Propaedeutic Internal Medicine and Joint Rheumatology Academic Program, School of Medicine, National and Kapodistrian University of Athens , Athens, Greece
| | - Federica Francesca Lunella
- 1 Institute of Cardiovascular Regeneration, Center of Molecular Medicine, JW Goethe University Frankfurt , Frankfurt, Germany .,2 Department of Biosciences, JW Goethe University Frankfurt , Frankfurt, Germany .,3 Department of Cardiology, Center of Internal Medicine, JW Goethe University Frankfurt , Frankfurt, Germany .,4 German Center of Cardiovascular Research (DZHK) , Rhein-Main Partner Site, Frankfurt, Germany
| | - Marco Sachse
- 1 Institute of Cardiovascular Regeneration, Center of Molecular Medicine, JW Goethe University Frankfurt , Frankfurt, Germany .,3 Department of Cardiology, Center of Internal Medicine, JW Goethe University Frankfurt , Frankfurt, Germany .,4 German Center of Cardiovascular Research (DZHK) , Rhein-Main Partner Site, Frankfurt, Germany
| | - Konstantinos Stellos
- 1 Institute of Cardiovascular Regeneration, Center of Molecular Medicine, JW Goethe University Frankfurt , Frankfurt, Germany .,3 Department of Cardiology, Center of Internal Medicine, JW Goethe University Frankfurt , Frankfurt, Germany .,4 German Center of Cardiovascular Research (DZHK) , Rhein-Main Partner Site, Frankfurt, Germany
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Tan XL, Sun M, Brady RD, Liu S, Llanos R, Cheung S, Wright DK, Casillas-Espinosa PM, Sashindranath M, O'Brien TJ, McDonald SJ, Turner BJ, Shultz SR. Transactive Response DNA-Binding Protein 43 Abnormalities after Traumatic Brain Injury. J Neurotrauma 2018; 36:87-99. [PMID: 29901412 DOI: 10.1089/neu.2017.5491] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Initial studies have found some evidence for transactive response DNA-binding protein 43 (TDP-43) abnormalities after traumatic brain injury (TBI), and the presence of protein inclusions consisting of TDP-43 are a pathological hallmark of amyotrophic lateral sclerosis (ALS), a condition associated with TBI. However, no study has characterized changes in TDP-43 phosphorylation, mislocalization, and fragmentation (i.e., abnormalities linked to hallmark TDP-43 pathology) after TBI, and how these relate to functional outcomes. Further, how TBI affects an individual with a known predisposition to TDP-43 pathology is unknown. Therefore, this study examined the effects of TBI on TDP-43 post-translational processing, localization, and behavioral outcomes in wild-type (WT) mice and mutant TDP-43A315T mice (i.e., mice predisposed to TDP-43 pathology) at 24 h and 1 week after TBI. Post-mortem brain tissue from human patients with acute TBI was also examined. Western blots found that WT mice given TBI had increased TDP-43 phosphorylation, mislocalization, and fragmentation compared with sham-injured WT mice. The TDP-43A315T mice given a TBI had exacerbated TDP-43 abnormalities, worse cell death, and cognitive deficits compared with all other groups. In the human TBI patients, the only significant finding was increased nuclear accumulation of phosphorylated TDP-43 fragments. The discrepancy between the robust mouse findings and the largely non-significant human findings may be due to factors including heterogeneity in clinical TBI, the small group sizes, and temporal complexities with TDP-43 abnormalities. These findings indicate that TBI can induce a number of TDP-43 abnormalities that may contribute to the neurological consequences of TBI, though further research is still needed.
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Affiliation(s)
- Xin Lin Tan
- 1 Department of Medicine, The University of Melbourne , Parkville, Victoria, Australia
| | - Mujun Sun
- 1 Department of Medicine, The University of Melbourne , Parkville, Victoria, Australia
| | - Rhys D Brady
- 1 Department of Medicine, The University of Melbourne , Parkville, Victoria, Australia
- 2 Department of Neuroscience, Monash University , Melbourne, Victoria, Australia
| | - Shijie Liu
- 2 Department of Neuroscience, Monash University , Melbourne, Victoria, Australia
| | - Roxana Llanos
- 3 Life and Environmental Sciences, Deakin University , Burwood, Victoria, Australia
| | - Steve Cheung
- 3 Life and Environmental Sciences, Deakin University , Burwood, Victoria, Australia
| | - David K Wright
- 2 Department of Neuroscience, Monash University , Melbourne, Victoria, Australia
| | - Pablo M Casillas-Espinosa
- 1 Department of Medicine, The University of Melbourne , Parkville, Victoria, Australia
- 2 Department of Neuroscience, Monash University , Melbourne, Victoria, Australia
| | - Maithili Sashindranath
- 4 Australian Center for Blood Disease, Monash University , Melbourne, Victoria, Australia
| | - Terence J O'Brien
- 1 Department of Medicine, The University of Melbourne , Parkville, Victoria, Australia
- 2 Department of Neuroscience, Monash University , Melbourne, Victoria, Australia
| | - Stuart J McDonald
- 5 Physiology, Anatomy, and Microbiology, La Trobe University , Bundoora, Victoria, Australia
| | - Bradley J Turner
- 6 The Florey Institute of Neuroscience and Mental Health , Parkville, Victoria, Australia
| | - Sandy R Shultz
- 1 Department of Medicine, The University of Melbourne , Parkville, Victoria, Australia
- 2 Department of Neuroscience, Monash University , Melbourne, Victoria, Australia
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Yamashita T, Kwak S. Cell death cascade and molecular therapy in ADAR2-deficient motor neurons of ALS. Neurosci Res 2018; 144:4-13. [PMID: 29944911 DOI: 10.1016/j.neures.2018.06.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 05/19/2018] [Accepted: 06/14/2018] [Indexed: 02/06/2023]
Abstract
TAR DNA-binding protein (TDP-43) pathology in the motor neurons is the most reliable pathological hallmark of amyotrophic lateral sclerosis (ALS), and motor neurons bearing TDP-43 pathology invariably exhibit failure in RNA editing at the GluA2 glutamine/arginine (Q/R) site due to down-regulation of adenosine deaminase acting on RNA 2 (ADAR2). Conditional ADAR2 knockout (AR2) mice display ALS-like phenotype, including progressive motor dysfunction due to loss of motor neurons. Motor neurons devoid of ADAR2 express Q/R site-unedited GluA2, and AMPA receptors with unedited GluA2 in their subunit assembly are abnormally permeable to Ca2+, which results in progressive neuronal death. Moreover, analysis of AR2 mice has demonstrated that exaggerated Ca2+ influx through the abnormal AMPA receptors overactivates calpain, a Ca2+-dependent protease, that cleaves TDP-43 into aggregation-prone fragments, which serve as seeds for TDP-43 pathology. Activated calpain also disrupts nucleo-cytoplasmic transport and gene expression by cleaving molecules involved in nucleocytoplasmic transport, including nucleoporins. These lines of evidence prompted us to develop molecular targeting therapy for ALS by normalization of disrupted intracellular environment due to ADAR2 down-regulation. In this review, we have summarized the work from our group on the cell death cascade in sporadic ALS and discussed a potential therapeutic strategy for ALS.
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Affiliation(s)
- Takenari Yamashita
- Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Shin Kwak
- Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan; Department of Neurology, Tokyo Medical University, 6-7-1, Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan.
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80
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Gao J, Wang L, Huntley ML, Perry G, Wang X. Pathomechanisms of TDP-43 in neurodegeneration. J Neurochem 2018; 146:10.1111/jnc.14327. [PMID: 29486049 PMCID: PMC6110993 DOI: 10.1111/jnc.14327] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 02/08/2018] [Accepted: 02/20/2018] [Indexed: 12/11/2022]
Abstract
Neurodegeneration, a term that refers to the progressive loss of structure and function of neurons, is a feature of many neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). There is no cure or treatment available that can prevent or reverse neurodegenerative conditions. The causes of neurodegeneration in these diseases remain largely unknown; yet, an extremely small proportion of these devastating diseases are associated with genetic mutations in proteins involved in a wide range of cellular pathways and processes. Over the past decade, it has become increasingly clear that the most notable neurodegenerative diseases, such as ALS, FTLD, and AD, share a common prominent pathological feature known as TAR DNA-binding protein 43 (TDP-43) proteinopathy, which is usually characterized by the presence of aberrant phosphorylation, ubiquitination, cleavage and/or nuclear depletion of TDP-43 in neurons and glial cells. The role of TDP-43 as a neurotoxicity trigger has been well documented in different in vitro and in vivo experimental models. As such, the investigation of TDP-43 pathomechanisms in various major neurodegenerative diseases is on the rise. Here, after a discussion of stages of TDP-43 proteinopathy during disease progression in various major neurodegenerative diseases, we review previous and most recent studies about the potential pathomechanisms with a particular emphasis on ALS, FTLD, and AD, and discuss the possibility of targeting TDP-43 as a common therapeutic approach to treat neurodegenerative diseases.
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Affiliation(s)
- Ju Gao
- Departments of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Luwen Wang
- Departments of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Mikayla L. Huntley
- Departments of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - George Perry
- College of Sciences, University of Texas at San Antonio, San Antonio, Texas, USA
| | - Xinglong Wang
- Departments of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
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Abstract
INTRODUCTION Nuclear factor TDP-43 is a ubiquitously expressed RNA binding protein that plays a key causative role in several neurodegenerative diseases, especially in the ALS/FTD spectrum. In addition, its aberrant aggregation and expression has been recently observed in other type of diseases, such as myopathies and Niemann-Pick C, a lysosomal storage disease. Areas covered: This review aims to specifically cover the post-translational modifications (PTMs) that can affect TDP-43 function and cellular status both in health and disease. To this date, these include phosphorylation, formation of C-terminal fragments, disulfide bridge formation, ubiquitination, acetylation, and sumoylation. Recently published articles on these subjects have been reviewed in this manuscript. Expert opinion: Targeting aberrant TDP-43 expression in neurodegenerative diseases is a very challenging task due to the fact that both its overexpression and downregulation are considerably toxic to cells. This characteristic makes it difficult to therapeutically target this protein in a generalized manner. An alternative approach could be the identification of specific aberrant PTMs that promote its aggregation or toxicity, and developing novel therapeutic approaches toward their selective modification.
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Affiliation(s)
- Emanuele Buratti
- a Department of Molecular Pathology , International Centre for Genetic Engineering and Biotechnology (ICGEB) , Trieste , Italy
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82
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Feneberg E, Gray E, Ansorge O, Talbot K, Turner MR. Towards a TDP-43-Based Biomarker for ALS and FTLD. Mol Neurobiol 2018; 55:7789-7801. [PMID: 29460270 PMCID: PMC6132775 DOI: 10.1007/s12035-018-0947-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 01/31/2018] [Indexed: 12/12/2022]
Abstract
TDP-43 accumulates in nerve cells of nearly all cases of amyotrophic lateral sclerosis (ALS; the commonest form of motor neuron disease) and in the majority of Tau-negative frontotemporal lobar degeneration (FTLD). There is currently no biochemical test or marker of disease activity for ALS or FTLD, and the clinical diagnosis depends on the opinion of an experienced neurologist. TDP-43 has a key role in the pathogenesis of ALS/FTLD. Measuring TDP-43 in easily accessible biofluids, such as blood or cerebrospinal fluid, might reduce diagnostic delay and offer a readout for use in future drug trials. However, attempts at measuring disease-specific forms of TDP-43 in peripheral biofluids of ALS and FTLD patients have not yielded consistent results, and only some of the pathological biochemical features of TDP-43 found in human brain tissue have been detected in clinical biofluids to date. Reflecting on the molecular pathology of TDP-43, this review provides a critical overview on biofluid studies and future directions to develop a TDP-43-based clinical biomarker for ALS and FTLD.
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Affiliation(s)
- Emily Feneberg
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK. .,John Radcliffe Hospital, West Wing Level 6, Oxford, OX3 9DU, UK.
| | - Elizabeth Gray
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Olaf Ansorge
- Neuropathology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Martin R Turner
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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83
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Filippini A, Bonini D, Giacopuzzi E, La Via L, Gangemi F, Colombi M, Barbon A. Differential Enzymatic Activity of Rat ADAR2 Splicing Variants Is Due to Altered Capability to Interact with RNA in the Deaminase Domain. Genes (Basel) 2018; 9:genes9020079. [PMID: 29419780 PMCID: PMC5852575 DOI: 10.3390/genes9020079] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/19/2018] [Accepted: 01/19/2018] [Indexed: 12/17/2022] Open
Abstract
In mammals, adenosine (A) to inosine (I) RNA editing is performed by adenosine deaminases acting on RNA (ADAR), ADAR1 and ADAR2 enzymes, encoded by mRNAs that might undergo splicing process. In rat, two splicing events produce several isoforms of ADAR2, called ADAR2a, ADAR2b, ADAR2e, and ADAR2f, but only ADAR2a and ADAR2b are translated into an active protein. In particular, they differ for ten amino acids located in the catalytic domain of ADAR2b. Here, we focused on these two isoforms, analyzing the splicing pattern and their different function during rat neuronal maturation. We found an increase of editing levels in cortical neurons overexpressing ADAR2a compared to those overexpressing ADAR2b. These results indicate ADAR2a isoform as the most active one, as reported for the homologous human short variant. Furthermore, we showed that the differential editing activity is not due to a different dimerization of the two isoforms; it seems to be linked to the ten amino acids loop of ADAR2b that might interfere with RNA binding, occupying the space volume in which the RNA should be present in case of binding. These data might shed light on the complexity of ADAR2 regulations.
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Affiliation(s)
- Alice Filippini
- Division of Biology and Genetics-Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
| | - Daniela Bonini
- Division of Biology and Genetics-Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
| | - Edoardo Giacopuzzi
- Division of Biology and Genetics-Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
| | - Luca La Via
- Division of Biology and Genetics-Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
| | - Fabrizio Gangemi
- Division of Physics, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
| | - Marina Colombi
- Division of Biology and Genetics-Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
| | - Alessandro Barbon
- Division of Biology and Genetics-Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
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84
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An easy-to-use FRET protein substrate to detect calpain cleavage in vitro and in vivo. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:221-230. [DOI: 10.1016/j.bbamcr.2017.10.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 10/10/2017] [Accepted: 10/30/2017] [Indexed: 01/06/2023]
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85
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Gu J, Wu F, Xu W, Shi J, Hu W, Jin N, Qian W, Wang X, Iqbal K, Gong CX, Liu F. TDP-43 suppresses tau expression via promoting its mRNA instability. Nucleic Acids Res 2017; 45:6177-6193. [PMID: 28335005 PMCID: PMC5449590 DOI: 10.1093/nar/gkx175] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 03/06/2017] [Indexed: 12/12/2022] Open
Abstract
In the brains of individuals with Alzheimer's disease (AD) and chronic traumatic encephalopathy, tau pathology is accompanied usually by intracellular aggregation of transactive response DNA-binding protein 43 (TDP-43). However, the role of TDP-43 in tau pathogenesis is not understood. Here, we investigated the role of TDP-43 in tau expression in vitro and in vivo. We found that TDP-43 suppressed tau expression by promoting its mRNA instability through the UG repeats of its 3΄-untranslated region (3΄-UTR). The C-terminal region of TDP-43 was required for this function. Neurodegenerative diseases-causing TDP-43 mutations affected tau mRNA instability differentially, in that some promoted and others did not significantly affect tau mRNA instability. The expression levels of tau and TDP-43 were inverse in the frontal cortex and the cerebellum. Accompanied with cytoplasmic accumulation of TDP-43, tau expression was elevated in TDP-43M337V transgenic mouse brains. The level of TDP-43, which is decreased in AD brains, was found to correlate negatively with the tau level in human brain. Our findings indicate that TDP-43 suppresses tau expression by promoting the instability of its mRNA. Down-regulation of TDP-43 may be involved in the tau pathology in AD and related neurodegenerative disorders.
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Affiliation(s)
- Jianlan Gu
- Key Laboratory of Neuroregeneration of Jiangsu and ministry of education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
- Department of Biochemistry and molecular biology, School of Medicine, Nantong University, Nantong, Jiangsu 226001, China
| | - Feng Wu
- Key Laboratory of Neuroregeneration of Jiangsu and ministry of education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
| | - Wen Xu
- Key Laboratory of Neuroregeneration of Jiangsu and ministry of education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
| | - Jianhua Shi
- Key Laboratory of Neuroregeneration of Jiangsu and ministry of education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
| | - Wen Hu
- Key Laboratory of Neuroregeneration of Jiangsu and ministry of education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
| | - Nana Jin
- Key Laboratory of Neuroregeneration of Jiangsu and ministry of education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Wei Qian
- Key Laboratory of Neuroregeneration of Jiangsu and ministry of education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
- Department of Biochemistry and molecular biology, School of Medicine, Nantong University, Nantong, Jiangsu 226001, China
| | - Xinglong Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Khalid Iqbal
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
| | - Cheng-Xin Gong
- Key Laboratory of Neuroregeneration of Jiangsu and ministry of education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
| | - Fei Liu
- Key Laboratory of Neuroregeneration of Jiangsu and ministry of education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA
- To whom correspondence should be addressed. Tel: +1 718 494 5263; Fax: +1 718 494 1080;
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86
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Calpain-Dependent Degradation of Nucleoporins Contributes to Motor Neuron Death in a Mouse Model of Chronic Excitotoxicity. J Neurosci 2017; 37:8830-8844. [PMID: 28821644 DOI: 10.1523/jneurosci.0730-17.2017] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 08/02/2017] [Accepted: 08/09/2017] [Indexed: 01/07/2023] Open
Abstract
Glutamate-mediated excitotoxicity induces neuronal death by altering various intracellular signaling pathways and is implicated as a common pathogenic pathway in many neurodegenerative diseases. In the case of motor neuron disease, there is significant evidence to suggest that the overactivation of AMPA receptors due to deficiencies in the expression and function of glial glutamate transporters GLT1 and GLAST plays an important role in the mechanisms of neuronal death. However, a causal role for glial glutamate transporter dysfunction in motor neuron death remains unknown. Here, we developed a new animal model of excitotoxicity by conditionally deleting astroglial glutamate transporters GLT1 and GLAST in the spinal cords of mice (GLAST+/-/GLT1-cKO). GLAST+/-/GLT1-cKO mice (both sexes) exhibited nuclear irregularity and calpain-mediated degradation of nuclear pore complexes (NPCs), which are responsible for nucleocytoplasmic transport. These abnormalities were associated with progressive motor neuron loss, severe paralysis, and shortened lifespan. The nuclear export inhibitor KPT-350 slowed but did not prevent motor neuron death, whereas long-term treatment of the AMPA receptor antagonist perampanel and the calpain inhibitor SNJ-1945 had more persistent beneficial effects. Thus, NPC degradation contributes to AMPA receptor-mediated excitotoxic motor neuronal death, and preventing NPC degradation has robust protective effects. Normalization of NPC function could be a novel therapeutic strategy for neurodegenerative disorders in which AMPA receptor-mediated excitotoxicity is a contributory factor.SIGNIFICANCE STATEMENT Despite glial glutamate transporter dysfunction leading to excitotoxicity has been documented in many neurological diseases, it remains unclear whether its dysfunction is a primary cause or secondary outcome of neuronal death at disease state. Here we show the combined loss of glial glutamate transporters GLT1 and GLAST in spinal cord caused motor neuronal death and hindlimb paralysis. Further, our novel mutant exhibits the nuclear irregularities and calpain-mediated progressive nuclear pore complex degradation. Our study reveals that glial glutamate transporter dysfunction is sufficient to cause motor neuronal death in vivo.
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87
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Osuru HP, Pramoonjago P, Abhyankar MM, Swanson E, Roker LA, Cathro H, Reddi PP. Immunolocalization of TAR DNA-binding protein of 43 kDa (TDP-43) in mouse seminiferous epithelium. Mol Reprod Dev 2017; 84:675-685. [PMID: 28600885 DOI: 10.1002/mrd.22851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 12/13/2022]
Abstract
TAR DNA-binding protein of 43 kDa (TDP-43) is an evolutionarily conserved, ubiquitously expressed, multi-functional DNA/RNA-binding protein with roles in gene transcription, mRNA splicing, stability, transport, micro RNA biogenesis, and suppression of transposons. Aberrant expression of TDP-43 in testis and sperm was recently shown to be associated with male infertility, which highlights the need to understand better the expression of TDP-43 in the testis. We previously cloned TDP-43 from a mouse testis cDNA library, and showed that it functions as a transcriptional repressor and regulates the precise spatiotemporal expression of the Acrv1 gene, which encodes the acrosomal protein SP-10, during spermatogenesis. Here, we performed immunoblotting and immunohistochemistry of the mouse testis using four separate antibodies recognizing the amino and carboxyl termini of TDP-43. TDP-43 is present in the nuclei of germ cells as well as Sertoli cells. TDP-43 expression begins in type B/intermediate spermatogonia, peaks in preleptotene spermatocytes, and becomes undetectable in leptotene and zygotene spermatocytes. Pachytene spermatocytes and early round spermatids again express TDP-43, but its abundance diminishes later in spermatids (at steps 5-8). Interestingly, two of the four antibodies showed TDP-43 expression in spermatids at steps 9-10, which coincides with the initial phase of the histone-to-protamine transition. Immunoreactivity patterns observed in the study suggest that TDP-43 assumes different conformational states at different stages of spermatogenesis. TDP-43 pathology has been extensively studied in the context of neurodegenerative diseases; its role in spermatogenesis warrants further detailed investigation of the involvement of TDP-43 in male infertility.
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Affiliation(s)
- Hari Prasad Osuru
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Patcharin Pramoonjago
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Mayuresh M Abhyankar
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Eric Swanson
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - LaToya Ann Roker
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Helen Cathro
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Prabhakara P Reddi
- Department of Comparative Biosciences, University of Illinois at Urbana Champaign, Urbana, Illinois
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88
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Smith EF, Shaw PJ, De Vos KJ. The role of mitochondria in amyotrophic lateral sclerosis. Neurosci Lett 2017; 710:132933. [PMID: 28669745 DOI: 10.1016/j.neulet.2017.06.052] [Citation(s) in RCA: 313] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 06/27/2017] [Indexed: 12/11/2022]
Abstract
Mitochondria are unique organelles that are essential for a variety of cellular processes including energy metabolism, calcium homeostasis, lipid biosynthesis, and apoptosis. Mitochondrial dysfunction is a prevalent feature of many neurodegenerative diseases including motor neuron disorders such as amyotrophic lateral sclerosis (ALS). Disruption of mitochondrial structure, dynamics, bioenergetics and calcium buffering has been extensively reported in ALS patients and model systems and has been suggested to be directly involved in disease pathogenesis. Here we review the alterations in mitochondrial parameters in ALS and examine the common pathways to dysfunction.
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Affiliation(s)
- Emma F Smith
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, S10 2HQ, UK
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, S10 2HQ, UK
| | - Kurt J De Vos
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, S10 2HQ, UK.
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89
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Kitamura A, Yuno S, Muto H, Kinjo M. Different aggregation states of a nuclear localization signal-tagged 25-kDa C-terminal fragment of TAR RNA/DNA-binding protein 43 kDa. Genes Cells 2017; 22:521-534. [PMID: 28497562 DOI: 10.1111/gtc.12495] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 03/27/2017] [Indexed: 12/14/2022]
Abstract
The mechanism and cause of motor neuronal cell death in amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disorder, are unknown; gain of function of oligomers and aggregation of misfolded proteins, including carboxyl-terminal fragments (CTFs) of TAR RNA/DNA-binding protein 43 kDa (TDP-43), have been proposed as important causative factors in the onset of ALS. We recently reported that a nuclear localization signal (NLS)-tagged 25-kDa CTF of TDP-43 (TDP25) could decrease the cell-death proportion compared with that promoted by TDP25. Here, we show oligomeric states of NLS-TDP25 and its detailed localization property using super-resolution fluorescence microscopy, FRET, fluorescence recovery after photobleaching, and fluorescence correlation spectroscopy analysis. NLS-TDP25 efficiently formed a nucleolar cap structure via RNA binding in the presence of actinomycin D, but TDP25 did not. Although cytoplasmic inclusion bodies including TDP25 had a disordered and immobile structure, NLS-TDP25 in the nucleolus was ordered and dynamic. In the diffuse state, TDP25 formed fewer oligomers and interacted with the molecular chaperone, HSP70; however, NLS-TDP25 formed oligomers. These results suggested that NLS-tagged TDP25 can change its structure to use ordered oligomeric but nontoxic state. Moreover, the structure of ordered oligomers as well as nuclear sequestration may be important in mediating cytotoxicity in ALS pathology.
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Affiliation(s)
- Akira Kitamura
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Sachiko Yuno
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Hideki Muto
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Masataka Kinjo
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
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90
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Amici DR, Pinal-Fernandez I, Mázala DAG, Lloyd TE, Corse AM, Christopher-Stine L, Mammen AL, Chin ER. Calcium dysregulation, functional calpainopathy, and endoplasmic reticulum stress in sporadic inclusion body myositis. Acta Neuropathol Commun 2017; 5:24. [PMID: 28330496 PMCID: PMC5363023 DOI: 10.1186/s40478-017-0427-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 03/12/2017] [Indexed: 01/08/2023] Open
Abstract
Sporadic inclusion body myositis (IBM) is the most common primary myopathy in the elderly, but its pathoetiology is still unclear. Perturbed myocellular calcium (Ca2+) homeostasis can exacerbate many of the factors proposed to mediate muscle degeneration in IBM, such as mitochondrial dysfunction, protein aggregation, and endoplasmic reticulum stress. Ca2+ dysregulation may plausibly be initiated in IBM by immune-mediated membrane damage and/or abnormally accumulating proteins, but no studies to date have investigated Ca2+ regulation in IBM patients. We first investigated protein expression via immunoblot in muscle biopsies from IBM, dermatomyositis, and non-myositis control patients, identifying several differentially expressed Ca2+-regulatory proteins in IBM. Next, we investigated the Ca2+-signaling transcriptome by RNA-seq, finding 54 of 183 (29.5%) genes from an unbiased list differentially expressed in IBM vs. controls. Using an established statistical approach to relate genes with causal transcription networks, Ca2+ abundance was considered a significant upstream regulator of observed whole-transcriptome changes. Post-hoc analyses of Ca2+-regulatory mRNA and protein data indicated a lower protein to transcript ratio in IBM vs. controls, which we hypothesized may relate to increased Ca2+-dependent proteolysis and decreased protein translation. Supporting this hypothesis, we observed robust (4-fold) elevation in the autolytic activation of a Ca2+-activated protease, calpain-1, as well as increased signaling for translational attenuation (eIF2α phosphorylation) downstream of the unfolded protein response. Finally, in IBM samples we observed mRNA and protein under-expression of calpain-3, the skeletal muscle-specific calpain, which broadly supports proper Ca2+ homeostasis. Together, these data provide novel insight into mechanisms by which intracellular Ca2+ regulation is perturbed in IBM and offer evidence of pathological downstream effects.
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91
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Han Y, Lin CY, Niu L. Functional Roles of the Edited Isoform of GluA2 in GluA2-Containing AMPA Receptor Channels. Biochemistry 2017; 56:1620-1631. [DOI: 10.1021/acs.biochem.6b01041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Yan Han
- Department of Chemistry and
Center for Neuroscience Research, University at Albany, State University of New York, Albany, New York 12222, United Stated
| | - Chi-Yen Lin
- Department of Chemistry and
Center for Neuroscience Research, University at Albany, State University of New York, Albany, New York 12222, United Stated
| | - Li Niu
- Department of Chemistry and
Center for Neuroscience Research, University at Albany, State University of New York, Albany, New York 12222, United Stated
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92
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Altered Intracellular Milieu of ADAR2-Deficient Motor Neurons in Amyotrophic Lateral Sclerosis. Genes (Basel) 2017; 8:genes8020060. [PMID: 28208729 PMCID: PMC5333049 DOI: 10.3390/genes8020060] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/25/2017] [Accepted: 01/26/2017] [Indexed: 12/12/2022] Open
Abstract
Transactive response DNA-binding protein (TDP-43) pathology, and failure of A-to-I conversion (RNA editing) at the glutamine/arginine (Q/R) site of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor subunit GluA2, are etiology-linked molecular abnormalities that concomitantly occur in the motor neurons of most patients with amyotrophic lateral sclerosis (ALS). Adenosine deaminase acting on RNA 2 (ADAR2) specifically catalyzes GluA2 Q/R site-RNA editing. Furthermore, conditional ADAR2 knockout mice (AR2) exhibit a progressive ALS phenotype with TDP-43 pathology in the motor neurons, which is the most reliable pathological marker of ALS. Therefore, the evidence indicates that ADAR2 downregulation is a causative factor in ALS, and AR2 mice exhibit causative molecular changes that occur in ALS. We discuss the contributors to ADAR2 downregulation and TDP-43 pathology in AR2 mouse motor neurons. We describe mechanisms of exaggerated Ca2+ influx amelioration via AMPA receptors, which is neuroprotective in ADAR2-deficient motor neurons with normalization of TDP-43 pathology in AR2 mice. Development of drugs to treat diseases requires appropriate animal models and a sensitive method of evaluating efficacy. Therefore, normalization of disrupted intracellular environments resulting from ADAR2 downregulation may be a therapeutic target for ALS. We discuss the development of targeted therapy for ALS using the AR2 mouse model.
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93
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Yamashita T, Aizawa H, Teramoto S, Akamatsu M, Kwak S. Calpain-dependent disruption of nucleo-cytoplasmic transport in ALS motor neurons. Sci Rep 2017; 7:39994. [PMID: 28045133 PMCID: PMC5206745 DOI: 10.1038/srep39994] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 11/30/2016] [Indexed: 12/11/2022] Open
Abstract
Nuclear dysfunction in motor neurons has been hypothesized to be a principal cause of amyotrophic lateral sclerosis (ALS) pathogenesis. Here, we investigated the mechanism by which the nuclear pore complex (NPC) is disrupted in dying motor neurons in a mechanistic ALS mouse model (adenosine deaminase acting on RNA 2 (ADAR2) conditional knockout (AR2) mice) and in ALS patients. We showed that nucleoporins (Nups) that constituted the NPC were cleaved by activated calpain via a Ca2+-permeable AMPA receptor-mediated mechanism in dying motor neurons lacking ADAR2 expression in AR2 mice. In these neurons, nucleo-cytoplasmic transport was disrupted, and the level of the transcript elongation enzyme RNA polymerase II phosphorylated at Ser2 was significantly decreased. Analogous changes were observed in motor neurons lacking ADAR2 immunoreactivity in sporadic ALS patients. Therefore, calpain-dependent NPC disruption may participate in ALS pathogenesis, and inhibiting Ca2+-mediated cell death signals may be a therapeutic strategy for ALS.
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Affiliation(s)
- Takenari Yamashita
- Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hitoshi Aizawa
- Department of Neurology, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo 160-0023, Japan
| | - Sayaka Teramoto
- Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Megumi Akamatsu
- Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shin Kwak
- Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.,Clinical Research Center for Medicine, International University of Health and Welfare, 6-1-14 Konodai, Ichikawa, Chiba 272-0827, Japan
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94
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Watanabe S, Ilieva H, Tamada H, Nomura H, Komine O, Endo F, Jin S, Mancias P, Kiyama H, Yamanaka K. Mitochondria-associated membrane collapse is a common pathomechanism in SIGMAR1- and SOD1-linked ALS. EMBO Mol Med 2016; 8:1421-1437. [PMID: 27821430 PMCID: PMC5167132 DOI: 10.15252/emmm.201606403] [Citation(s) in RCA: 179] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 09/21/2016] [Accepted: 09/27/2016] [Indexed: 01/11/2023] Open
Abstract
A homozygous mutation in the gene for sigma 1 receptor (Sig1R) is a cause of inherited juvenile amyotrophic lateral sclerosis (ALS16). Sig1R localizes to the mitochondria-associated membrane (MAM), which is an interface of mitochondria and endoplasmic reticulum. However, the role of the MAM in ALS is not fully elucidated. Here, we identified a homozygous p.L95fs mutation of Sig1R as a novel cause of ALS16. ALS-linked Sig1R variants were unstable and incapable of binding to inositol 1,4,5-triphosphate receptor type 3 (IP3R3). The onset of mutant Cu/Zn superoxide dismutase (SOD1)-mediated ALS disease in mice was accelerated when Sig1R was deficient. Moreover, either deficiency of Sig1R or accumulation of mutant SOD1 induced MAM disruption, resulting in mislocalization of IP3R3 from the MAM, calpain activation, and mitochondrial dysfunction. Our findings indicate that a loss of Sig1R function is causative for ALS16, and collapse of the MAM is a common pathomechanism in both Sig1R- and SOD1-linked ALS Furthermore, our discovery of the selective enrichment of IP3R3 in motor neurons suggests that integrity of the MAM is crucial for the selective vulnerability in ALS.
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Affiliation(s)
- Seiji Watanabe
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi, Japan
| | - Hristelina Ilieva
- Houston Methodist Hospital, Houston, TX, USA
- Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
| | - Hiromi Tamada
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Hanae Nomura
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi, Japan
| | - Okiru Komine
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi, Japan
| | - Fumito Endo
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi, Japan
| | - Shijie Jin
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi, Japan
| | - Pedro Mancias
- Department of Pediatrics, The University of Texas Medical School at Houston, Houston, TX, USA
| | - Hiroshi Kiyama
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Koji Yamanaka
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi, Japan
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95
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Ono Y, Saido TC, Sorimachi H. Calpain research for drug discovery: challenges and potential. Nat Rev Drug Discov 2016; 15:854-876. [PMID: 27833121 DOI: 10.1038/nrd.2016.212] [Citation(s) in RCA: 186] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Calpains are a family of proteases that were scientifically recognized earlier than proteasomes and caspases, but remain enigmatic. However, they are known to participate in a multitude of physiological and pathological processes, performing 'limited proteolysis' whereby they do not destroy but rather modulate the functions of their substrates. Calpains are therefore referred to as 'modulator proteases'. Multidisciplinary research on calpains has begun to elucidate their involvement in pathophysiological mechanisms. Therapeutic strategies targeting malfunctions of calpains have been developed, driven primarily by improvements in the specificity and bioavailability of calpain inhibitors. Here, we review the calpain superfamily and calpain-related disorders, and discuss emerging calpain-targeted therapeutic strategies.
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Affiliation(s)
- Yasuko Ono
- Calpain Project, Department of Advanced Science for Biomolecules, Tokyo Metropolitan Institute of Medical Science (IGAKUKEN), 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hiroyuki Sorimachi
- Calpain Project, Department of Advanced Science for Biomolecules, Tokyo Metropolitan Institute of Medical Science (IGAKUKEN), 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
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96
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Filippini A, Bonini D, La Via L, Barbon A. The Good and the Bad of Glutamate Receptor RNA Editing. Mol Neurobiol 2016; 54:6795-6805. [DOI: 10.1007/s12035-016-0201-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 10/11/2016] [Indexed: 12/15/2022]
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97
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Vintilescu CR, Afreen S, Rubino AE, Ferreira A. The Neurotoxic TAU 45-230 Fragment Accumulates in Upper and Lower Motor Neurons in Amyotrophic Lateral Sclerosis Subjects. Mol Med 2016; 22:477-486. [PMID: 27496042 PMCID: PMC5072411 DOI: 10.2119/molmed.2016.00095] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 07/23/2016] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive and lethal neurodegenerative disease characterized by the loss of upper and lower motor neurons leading to muscle paralysis in affected individuals. Numerous mechanisms have been implicated in the death of these neurons. However, the pathobiology of this disease has not been completely elucidated. In the present study, we investigated to what extent tau cleavage and the generation of the neurotoxic tau45-230 fragment is associated with ALS. Quantitative Western blot analysis indicated that high levels of tau45-230 accumulated in lumbar and cervical spinal cord specimens obtained from ALS subjects. This neurotoxic tau fragment was also detected in ALS upper motor neurons located in the precentral gyrus. Our results also showed that tau45-230 aggregates were present in the spinal cord of ALS patients. On the other hand, this neurotoxic fragment was not generated in a mouse model of a familial form of this disease. Together, these results suggest a potential role for this neurotoxic tau fragment in the mechanisms leading to the degeneration of motor neurons in the context of sporadic ALS.
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Affiliation(s)
- Claudia R Vintilescu
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, IL 60611
| | - Sana Afreen
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, IL 60611
| | - Ashlee E Rubino
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, IL 60611
| | - Adriana Ferreira
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, IL 60611
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98
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Periyakaruppiah A, de la Fuente S, Arumugam S, Bahí N, Garcera A, Soler RM. Autophagy modulators regulate survival motor neuron protein stability in motoneurons. Exp Neurol 2016; 283:287-97. [PMID: 27373203 DOI: 10.1016/j.expneurol.2016.06.032] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 06/06/2016] [Accepted: 06/28/2016] [Indexed: 12/31/2022]
Affiliation(s)
- Ambika Periyakaruppiah
- Unitat de Senyalització Neuronal, Dep. Medicina Experimental, Universitat de Lleida-IRBLLEIDA, Rovira Roure 80, 25198 Lleida, Spain
| | - Sandra de la Fuente
- Unitat de Senyalització Neuronal, Dep. Medicina Experimental, Universitat de Lleida-IRBLLEIDA, Rovira Roure 80, 25198 Lleida, Spain
| | - Saravanan Arumugam
- Unitat de Senyalització Neuronal, Dep. Medicina Experimental, Universitat de Lleida-IRBLLEIDA, Rovira Roure 80, 25198 Lleida, Spain
| | - Núria Bahí
- Unitat de Senyalització Neuronal, Dep. Medicina Experimental, Universitat de Lleida-IRBLLEIDA, Rovira Roure 80, 25198 Lleida, Spain
| | - Ana Garcera
- Unitat de Senyalització Neuronal, Dep. Medicina Experimental, Universitat de Lleida-IRBLLEIDA, Rovira Roure 80, 25198 Lleida, Spain
| | - Rosa M Soler
- Unitat de Senyalització Neuronal, Dep. Medicina Experimental, Universitat de Lleida-IRBLLEIDA, Rovira Roure 80, 25198 Lleida, Spain.
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99
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Akamatsu M, Yamashita T, Hirose N, Teramoto S, Kwak S. The AMPA receptor antagonist perampanel robustly rescues amyotrophic lateral sclerosis (ALS) pathology in sporadic ALS model mice. Sci Rep 2016; 6:28649. [PMID: 27350567 PMCID: PMC4923865 DOI: 10.1038/srep28649] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/06/2016] [Indexed: 02/08/2023] Open
Abstract
Both TDP-43 pathology and failure of RNA editing of AMPA receptor subunit GluA2, are etiology-linked molecular abnormalities that concomitantly occur in the motor neurons of the majority of patients with amyotrophic lateral sclerosis (ALS). AR2 mice, in which an RNA editing enzyme adenosine deaminase acting on RNA 2 (ADAR2) is conditionally knocked out in the motor neurons, exhibit a progressive ALS phenotype with TDP-43 pathology in the motor neurons through a Ca2+-permeable AMPA receptor-mediated mechanism. Therefore, amelioration of the increased Ca2+ influx by AMPA receptor antagonists may be a potential ALS therapy. Here, we showed that orally administered perampanel, a selective, non-competitive AMPA receptor antagonist significantly prevented the progression of the ALS phenotype and normalized the TDP-43 pathology-associated death of motor neurons in the AR2 mice. Given that perampanel is an approved anti-epileptic drug, perampanel is a potential candidate ALS drug worthy of a clinical trial.
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Affiliation(s)
- Megumi Akamatsu
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Department of Neuropathology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Takenari Yamashita
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Department of Neuropathology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Naoki Hirose
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Department of Neuropathology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Sayaka Teramoto
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Department of Neuropathology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shin Kwak
- Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan.,Clinical Research Center for Medicine, International University of Health and Welfare, Ichikawa, Chiba, Japan
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100
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Manghera M, Ferguson-Parry J, Douville RN. TDP-43 regulates endogenous retrovirus-K viral protein accumulation. Neurobiol Dis 2016; 94:226-36. [PMID: 27370226 DOI: 10.1016/j.nbd.2016.06.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 05/30/2016] [Accepted: 06/27/2016] [Indexed: 12/12/2022] Open
Abstract
The concomitant expression of neuronal TAR DNA binding protein 43 (TDP-43) and human endogenous retrovirus-K (ERVK) is a hallmark of ALS. Since the involvement of TDP-43 in retrovirus replication remains controversial, we sought to evaluate whether TDP-43 exerts an effect on ERVK expression. In this study, TDP-43 bound the ERVK promoter in the context of inflammation or proteasome inhibition, with no effect on ERVK transcription. However, over-expression of ALS-associated aggregating forms of TDP-43, but not wild-type TDP-43, significantly enhanced ERVK viral protein accumulation. Human astrocytes and neurons further demonstrated cell-type specific differences in their ability to express and clear ERVK proteins during inflammation and proteasome inhibition. Astrocytes, but not neurons, were able to clear excess ERVK proteins through stress granule formation and autophagy. In vitro findings were validated in autopsy motor cortex tissue from patients with ALS and neuro-normal controls. We further confirmed marked enhancement of ERVK in cortical neurons of patients with ALS. Despite evidence of enhanced stress granule and autophagic response in ALS cortical neurons, these cells failed to clear excess ERVK protein accumulation. This highlights how multiple cellular pathways, in conjunction with disease-associated mutations, can converge to modulate the expression and clearance of viral gene products from genomic elements such as ERVK. In ALS, ERVK protein aggregation is a novel aspect of TDP-43 misregulation contributing towards the pathology of this neurodegenerative disease.
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Affiliation(s)
- Mamneet Manghera
- Department of Biology, University of Winnipeg, 599 Portage Avenue, Winnipeg, Manitoba R3B 2G3, Canada
| | - Jennifer Ferguson-Parry
- Department of Biology, University of Winnipeg, 599 Portage Avenue, Winnipeg, Manitoba R3B 2G3, Canada
| | - Renée N Douville
- Department of Biology, University of Winnipeg, 599 Portage Avenue, Winnipeg, Manitoba R3B 2G3, Canada; Department of Immunology, University of Manitoba, 750 McDermot Avenue, Winnipeg, Manitoba R3E 0T5, Canada.
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