1
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García Morato J, Gloeckner CJ, Kahle PJ. Proteomics elucidating physiological and pathological functions of TDP-43. Proteomics 2023; 23:e2200410. [PMID: 37671599 DOI: 10.1002/pmic.202200410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 08/02/2023] [Accepted: 08/10/2023] [Indexed: 09/07/2023]
Abstract
Trans-activation response DNA binding protein of 43 kDa (TDP-43) regulates a great variety of cellular processes in the nucleus and cytosol. In addition, a defined subset of neurodegenerative diseases is characterized by nuclear depletion of TDP-43 as well as cytosolic mislocalization and aggregation. To perform its diverse functions TDP-43 can associate with different ribonucleoprotein complexes. Combined with transcriptomics, MS interactome studies have unveiled associations between TDP-43 and the spliceosome machinery, polysomes and RNA granules. Moreover, the highly dynamic, low-valency interactions regulated by its low-complexity domain calls for innovative proximity labeling methodologies. In addition to protein partners, the analysis of post-translational modifications showed that they may play a role in the nucleocytoplasmic shuttling, RNA binding, liquid-liquid phase separation and protein aggregation of TDP-43. Here we review the various TDP-43 ribonucleoprotein complexes characterized so far, how they contribute to the diverse functions of TDP-43, and roles of post-translational modifications. Further understanding of the fluid dynamic properties of TDP-43 in ribonucleoprotein complexes, RNA granules, and self-assemblies will advance the understanding of RNA processing in cells and perhaps help to develop novel therapeutic approaches for TDPopathies.
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Affiliation(s)
- Jorge García Morato
- Laboratory of Functional Neurogenetics, Department of Neurodegeneration, German Center of Neurodegenerative Diseases and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Christian Johannes Gloeckner
- Research Group Functional Neuroproteomics, German Center of Neurodegenerative Diseases, Tübingen, Germany
- Core Facility for Medical Bioanalytics, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Philipp J Kahle
- Laboratory of Functional Neurogenetics, Department of Neurodegeneration, German Center of Neurodegenerative Diseases and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Department of Biochemistry, University of Tübingen, Tübingen, Germany
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2
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Ortiz GG, Ramírez-Jirano J, Arizaga RL, Delgado-Lara DLC, Torres-Sánchez ED. Frontotemporal-TDP and LATE Neurocognitive Disorders: A Pathophysiological and Genetic Approach. Brain Sci 2023; 13:1474. [PMID: 37891841 PMCID: PMC10605418 DOI: 10.3390/brainsci13101474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/07/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023] Open
Abstract
Frontotemporal lobar degeneration (FTLD) belongs to a heterogeneous group of highly complex neurodegenerative diseases and represents the second cause of presenile dementia in individuals under 65. Frontotemporal-TDP is a subgroup of frontotemporal dementia characterized by the aggregation of abnormal protein deposits, predominantly transactive response DNA-binding protein 43 (TDP-43), in the frontal and temporal brain regions. These deposits lead to progressive degeneration of neurons resulting in cognitive and behavioral impairments. Limbic age-related encephalopathy (LATE) pertains to age-related cognitive decline primarily affecting the limbic system, which is crucial for memory, emotions, and learning. However, distinct, emerging research suggests a potential overlap in pathogenic processes, with some cases of limbic encephalopathy displaying TDP-43 pathology. Genetic factors play a pivotal role in both disorders. Mutations in various genes, such as progranulin (GRN) and chromosome 9 open reading frame 72 (C9orf72), have been identified as causative in frontotemporal-TDP. Similarly, specific genetic variants have been associated with an increased risk of developing LATE. Understanding these genetic links provides crucial insights into disease mechanisms and the potential for targeted therapies.
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Affiliation(s)
- Genaro Gabriel Ortiz
- Department of Philosophical and Methodological Disciplines, University Health Sciences Center, University of Guadalajara, Guadalajara 44340, Jalisco, Mexico;
- Postgraduate Gerontology Program, University Health Sciences Center, University of Guadalajara, Guadalajara 44340, Jalisco, Mexico
| | - Javier Ramírez-Jirano
- Neurosciences Division, Western Biomedical Research Center, Mexican Social Security Institute, IMSS, Guadalajara 44340, Jalisco, Mexico;
| | - Raul L. Arizaga
- Public Health Department, School of Medicine, University of Buenos Aires, Buenos Aires C1121ABG, Argentina;
| | - Daniela L. C. Delgado-Lara
- Department of Philosophical and Methodological Disciplines, University Health Sciences Center, University of Guadalajara, Guadalajara 44340, Jalisco, Mexico;
- Departamento Académico de Formación Universitaria, Ciencias de la Salud, Universidad Autónoma de Guadalajara, Zapopan 45129, Jalisco, Mexico
| | - Erandis D. Torres-Sánchez
- Department of Medical and Life Sciences, University Center of la Cienega, University of Guadalajara, Ocotlan 47820, Jalisco, Mexico
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3
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Brunette S, Sharma A, Bell R, Puente L, Megeney LA. Caspase 3 exhibits a yeast metacaspase proteostasis function that protects mitochondria from toxic TDP43 aggregates. MICROBIAL CELL (GRAZ, AUSTRIA) 2023; 10:157-169. [PMID: 37545643 PMCID: PMC10399456 DOI: 10.15698/mic2023.08.801] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 06/22/2023] [Accepted: 06/27/2023] [Indexed: 08/08/2023]
Abstract
Caspase 3 activation is a hallmark of cell death and there is a strong correlation between elevated protease activity and evolving pathology in neurodegenerative disease, such as amyotrophic lateral sclerosis (ALS). At the cellular level, ALS is characterized by protein aggregates and inclusions, comprising the RNA binding protein TDP-43, which are hypothesized to trigger pathogenic activation of caspase 3. However, a growing body of evidence indicates this protease is essential for ensuring cell viability during growth, differentiation and adaptation to stress. Here, we explored whether caspase 3 acts to disperse toxic protein aggregates, a proteostasis activity first ascribed to the distantly related yeast metacaspase ScMCA1. We demonstrate that human caspase 3 can functionally substitute for the ScMCA1 and limit protein aggregation in yeast, including TDP-43 inclusions. Proteomic analysis revealed that disrupting caspase 3 in the same yeast substitution model resulted in detrimental TDP-43/mitochondrial protein associations. Similarly, suppression of caspase 3, in either murine or human skeletal muscle cells, led to accumulation of TDP-43 aggregates and impaired mitochondrial function. These results suggest that caspase 3 is not inherently pathogenic, but may act as a compensatory proteostasis factor, to limit TDP-43 protein inclusions and protect organelle function in aggregation related degenerative disease.
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Affiliation(s)
- Steve Brunette
- Regenerative Medicine Program, Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, ON K1H 8L6, Canada
| | - Anupam Sharma
- Regenerative Medicine Program, Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, ON K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Ryan Bell
- Regenerative Medicine Program, Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, ON K1H 8L6, Canada
| | - Lawrence Puente
- Regenerative Medicine Program, Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, ON K1H 8L6, Canada
| | - Lynn A Megeney
- Regenerative Medicine Program, Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, ON K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Medicine, University of Ottawa, Ottawa, ON, Canada
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4
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Arnold FJ, Nguyen AD, Bedlack RS, Bennett CL, La Spada AR. Intercellular transmission of pathogenic proteins in ALS: Exploring the pathogenic wave. Neurobiol Dis 2023:106218. [PMID: 37394036 DOI: 10.1016/j.nbd.2023.106218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 06/16/2023] [Accepted: 06/28/2023] [Indexed: 07/04/2023] Open
Abstract
In patients with amyotrophic lateral sclerosis (ALS), disease symptoms and pathology typically spread in a predictable spatiotemporal pattern beginning at a focal site of onset and progressing along defined neuroanatomical tracts. Like other neurodegenerative diseases, ALS is characterized by the presence of protein aggregates in postmortem patient tissue. Cytoplasmic, ubiquitin-positive aggregates of TDP-43 are observed in approximately 97% of sporadic and familial ALS patients, while SOD1 inclusions are likely specific to cases of SOD1-ALS. Additionally, the most common subtype of familial ALS, caused by a hexanucleotide repeat expansion in the first intron of the C9orf72 gene (C9-ALS), is further characterized by the presence of aggregated dipeptide repeat proteins (DPRs). As we will describe, cell-to-cell propagation of these pathological proteins tightly correlates with the contiguous spread of disease. While TDP-43 and SOD1 are capable of seeding protein misfolding and aggregation in a prion-like manner, C9orf72 DPRs appear to induce (and transmit) a 'disease state' more generally. Multiple mechanisms of intercellular transport have been described for all of these proteins, including anterograde and retrograde axonal transport, extracellular vesicle secretion, and macropinocytosis. In addition to neuron-to-neuron transmission, transmission of pathological proteins occurs between neurons and glia. Given that the spread of ALS disease pathology corresponds with the spread of symptoms in patients, the various mechanisms by which ALS-associated protein aggregates propagate through the central nervous system should be closely examined.
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Affiliation(s)
- F J Arnold
- Department of Pathology and Laboratory Medicine, University of California, Irvine, Irvine, CA, USA; Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA
| | - A D Nguyen
- Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA
| | - R S Bedlack
- Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA
| | - C L Bennett
- Department of Pathology and Laboratory Medicine, University of California, Irvine, Irvine, CA, USA; Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA.
| | - A R La Spada
- Department of Pathology and Laboratory Medicine, University of California, Irvine, Irvine, CA, USA; Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA; Departments of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA; Department of Neurology, University of California, Irvine, Irvine, CA, USA; Department of Biological Chemistry, University of California, Irvine, Irvine, CA, USA; UCI Center for Neurotherapeutics, University of California, Irvine, Irvine, CA 92697, USA.
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5
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Fogarty MJ. Loss of larger hypoglossal motor neurons in aged Fischer 344 rats. Respir Physiol Neurobiol 2023:104092. [PMID: 37331418 DOI: 10.1016/j.resp.2023.104092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/06/2023] [Accepted: 06/15/2023] [Indexed: 06/20/2023]
Abstract
The intrinsic (longitudinal, transversalis and verticalis) and extrinsic (genioglossus, styloglossus, hyoglossus and geniohyoid) tongue muscles are innervated by hypoglossal motor neurons (MNs). Tongue muscle activations occur during many behaviors: maintaining upper airway patency, chewing, swallowing, vocalization, vomiting, coughing, sneezing and grooming/sexual activities. In the tongues of the elderly, reduced oral motor function and strength contribute to increased risk of obstructive sleep apnoea. Tongue muscle atrophy and weakness is also described in rats, yet hypoglossal MN numbers are unknown. In young (6-months, n=10) and old (24-months, n=8) female and male Fischer 344 (F344) rats, stereological assessment of hypoglossal MN numbers and surface areas were performed on 16µm Nissl-stained brainstem cryosections. We observed a robust loss of ~15% of hypoglossal MNs and a modest ~8% reduction in their surface areas with age. In the larger size tertile of hypoglossal MNs, age-associated loss of hypoglossal MNs approached ~30% These findings uncover a potential neurogenic locus of pathology for age-associated tongue dysfunctions.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905.
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6
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Jeon YM, Kwon Y, Lee S, Kim HJ. Potential roles of the endoplasmic reticulum stress pathway in amyotrophic lateral sclerosis. Front Aging Neurosci 2023; 15:1047897. [PMID: 36875699 PMCID: PMC9974850 DOI: 10.3389/fnagi.2023.1047897] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 01/16/2023] [Indexed: 02/17/2023] Open
Abstract
The endoplasmic reticulum (ER) is a major organelle involved in protein quality control and cellular homeostasis. ER stress results from structural and functional dysfunction of the organelle, along with the accumulation of misfolded proteins and changes in calcium homeostasis, it leads to ER stress response pathway such as unfolded protein response (UPR). Neurons are particularly sensitive to the accumulation of misfolded proteins. Thus, the ER stress is involved in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, prion disease and motor neuron disease (MND). Recently, the complex involvement of ER stress pathways has been demonstrated in experimental models of amyotrophic lateral sclerosis (ALS)/MND using pharmacological and genetic manipulation of the unfolded protein response (UPR), an adaptive response to ER stress. Here, we aim to provide recent evidence demonstrating that the ER stress pathway is an essential pathological mechanism of ALS. In addition, we also provide therapeutic strategies that can help treat diseases by targeting the ER stress pathway.
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Affiliation(s)
- Yu-Mi Jeon
- Dementia Research Group, Korea Brain Research Institute, Daegu, Republic of Korea
| | - Younghwi Kwon
- Dementia Research Group, Korea Brain Research Institute, Daegu, Republic of Korea
| | - Shinrye Lee
- Dementia Research Group, Korea Brain Research Institute, Daegu, Republic of Korea
| | - Hyung-Jun Kim
- Dementia Research Group, Korea Brain Research Institute, Daegu, Republic of Korea.,Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea
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7
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Zhou Z, Fan Y, Zong R, Tan K. The mitochondrial unfolded protein response: A multitasking giant in the fight against human diseases. Ageing Res Rev 2022; 81:101702. [PMID: 35908669 DOI: 10.1016/j.arr.2022.101702] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 07/15/2022] [Accepted: 07/26/2022] [Indexed: 02/06/2023]
Abstract
Mitochondria, which serve as the energy factories of cells, are involved in cell differentiation, calcium homeostasis, amino acid and fatty acid metabolism and apoptosis. In response to environmental stresses, mitochondrial homeostasis is regulated at both the organelle and molecular levels to effectively maintain the number and function of mitochondria. The mitochondrial unfolded protein response (UPRmt) is an adaptive intracellular stress mechanism that responds to stress signals by promoting the transcription of genes encoding mitochondrial chaperones and proteases. The mechanism of the UPRmt in Caenorhabditis elegans (C. elegans) has been clarified over time, and the main regulatory factors include ATFS-1, UBL-5 and DVE-1. In mammals, the activation of the UPRmt involves eIF2α phosphorylation and the uORF-regulated expression of CHOP, ATF4 and ATF5. Several additional factors, such as SIRT3 and HSF1, are also involved in regulating the UPRmt. A deep and comprehensive exploration of the UPRmt can provide new directions and strategies for the treatment of human diseases, including aging, neurodegenerative diseases, cardiovascular diseases and diabetes. In this review, we mainly discuss the function of UPRmt, describe the regulatory mechanisms of UPRmt in C. elegans and mammals, and summarize the relationship between UPRmt and various human diseases.
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Affiliation(s)
- Zixin Zhou
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Province Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China; State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, University of Chinese Academy of Sciences, Beijing, China
| | - Yumei Fan
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Province Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China
| | - Ruikai Zong
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Province Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China
| | - Ke Tan
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Province Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China.
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8
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Garg DK, Bhat R. Modulation of assembly of TDP-43 low-complexity domain by heparin: From droplets to amyloid fibrils. Biophys J 2022; 121:2568-2582. [PMID: 35644946 PMCID: PMC9300664 DOI: 10.1016/j.bpj.2022.05.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 09/03/2021] [Accepted: 05/25/2022] [Indexed: 11/02/2022] Open
Abstract
TAR DNA-binding protein 43 (TDP-43) is an RNA-regulating protein that carries out many cellular functions through liquid-liquid phase separation (LLPS). The LLPS of TDP-43 is mediated by its C-terminal low-complexity domain (TDP43-LCD) corresponding to the region 267-414. In neurodegenerative disorders amyotrophic lateral sclerosis and frontotemporal dementia, pathological inclusions of the TDP-43 are found that are rich in the C-terminal fragments of ∼25 and ∼35 kDa, of which TDP43-LCD is a part. Thus, understanding the assembly process of TDP43-LCD is essential, given its involvement in the formation of both functional liquid-like assemblies and solid- or gel-like pathological aggregates. Here, we show that the solution pH and salt modulate TDP43-LCD LLPS. A gradual reduction in the pH below its isoelectric point of 9.8 results in a monotonic decrease of TDP43-LCD LLPS due to charge-charge repulsion between monomers, while at pH 6 and below no LLPS was observed. The addition of heparin to TDP43-LCD solution at pH 6, at a 1:2 heparin-to-TDP43-LCD molar ratio, promotes TDP43-LCD LLPS, while at higher concentration, it disrupts LLPS through a reentrant phase transition. Upon incubation at pH 6, TDP43-LCD undergoes gelation without phase separation. However, in the reentrant regime in the presence of a high heparin concentration, it forms thick amyloid aggregates that are significantly more SDS resistant than the gel. The results indicate that the material nature of the TDP43-LCD assembly products can be modulated by heparin which is significant in the context of liquid-to-solid phase transition observed in TDP-43 proteinopathies. Our findings are also crucial in relation to similar transitions that could occur due to alteration in the molecular level interactions among various multivalent biomolecules involving other LCDs and RNAs.
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Affiliation(s)
| | - Rajiv Bhat
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India.
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9
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Sharma A, Dey P. Novel insights into the structural changes induced by disease-associated mutations in TDP-43: a computational approach. J Biomol Struct Dyn 2022:1-11. [PMID: 35751132 DOI: 10.1080/07391102.2022.2092551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Over the last two decades, the pathogenic aggregation of TAR DNA-binding protein 43 (TDP-43) is found to be strongly associated with several fatal neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTD), etc. While the mutations and truncation in TDP-43 protein have been suggested to be responsible for TDP-43 pathogenesis by accelerating the aggregation process, the effects of these mutations on the bio-mechanism of pathological TDP-43 protein remained poorly understood. Investigating this at the molecular level, we formulized an integrated workflow of molecular dynamic simulation and machine learning models (MD-ML). By performing an extensive structural analysis of three disease-related mutations (i.e., I168A, D169G, and I168A-D169G) in the conserved RNA recognition motifs (RRM1) of TDP-43, we observed that the I168A-D169G double mutant delineates the highest packing of the protein inner core as compared to the other mutations, which may indicate more stability and higher chances of pathogenesis. Moreover, through our MD-ML workflow, we identified the biological descriptors of TDP-43 which includes the interacting residue pairs and individual protein residues that influence the stability of the protein and could be experimentally evaluated to develop potential therapeutic strategies.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Abhibhav Sharma
- School of Computer and System Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Pinki Dey
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
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10
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Zhao C, Liao Y, Rahaman A, Kumar V. Towards Understanding the Relationship Between ER Stress and Unfolded Protein Response in Amyotrophic Lateral Sclerosis. Front Aging Neurosci 2022; 14:892518. [PMID: 35783140 PMCID: PMC9248913 DOI: 10.3389/fnagi.2022.892518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Biological stress due to the aberrant buildup of misfolded/unfolded proteins in the endoplasmic reticulum (ER) is considered a key reason behind many human neurodegenerative diseases. Cells adapted to ER stress through the activation of an integrated signal transduction pathway known as the unfolded protein response (UPR). Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by degeneration of the motor system. It has largely been known that ER stress plays an important role in the pathogenesis of ALS through the dysregulation of proteostasis. Moreover, accumulating evidence indicates that ER stress and UPR are important players in TDP-43 pathology. In this mini-review, the complex interplay between ER stress and the UPR in ALS and TDP-43 pathology will be explored by taking into account the studies from in vitro and in vivo models of ALS. We also discuss therapeutic strategies to control levels of ER stress and UPR signaling components that have contrasting effects on ALS pathogenesis.
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Affiliation(s)
- Chenxuan Zhao
- School of Engineering, College of Technology and Business, Guangzhou, China
| | - Yong Liao
- Center of Scientific Research, Maoming People’s Hospital, Maoming, China
- *Correspondence: Yong Liao Vijay Kumar
| | - Abdul Rahaman
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Vijay Kumar
- Amity Institute of Neuropsychology & Neurosciences (AINN), Amity University, Noida, India
- *Correspondence: Yong Liao Vijay Kumar
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Moretto E, Stuart S, Surana S, Vargas JNS, Schiavo G. The Role of Extracellular Matrix Components in the Spreading of Pathological Protein Aggregates. Front Cell Neurosci 2022; 16:844211. [PMID: 35573838 PMCID: PMC9100790 DOI: 10.3389/fncel.2022.844211] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 03/08/2022] [Indexed: 11/23/2022] Open
Abstract
Several neurodegenerative diseases are characterized by the accumulation of aggregated misfolded proteins. These pathological agents have been suggested to propagate in the brain via mechanisms similar to that observed for the prion protein, where a misfolded variant is transferred from an affected brain region to a healthy one, thereby inducing the misfolding and/or aggregation of correctly folded copies. This process has been characterized for several proteins, such as α-synuclein, tau, amyloid beta (Aβ) and less extensively for huntingtin and TDP-43. α-synuclein, tau, TDP-43 and huntingtin are intracellular proteins, and their aggregates are located in the cytosol or nucleus of neurons. They have been shown to spread between cells and this event occurs, at least partially, via secretion of these protein aggregates in the extracellular space followed by re-uptake. Conversely, Aβ aggregates are found mainly extracellularly, and their spreading occurs in the extracellular space between brain regions. Due to the inherent nature of their spreading modalities, these proteins are exposed to components of the extracellular matrix (ECM), including glycans, proteases and core matrix proteins. These ECM components can interact with or process pathological misfolded proteins, potentially changing their properties and thus regulating their spreading capabilities. Here, we present an overview of the documented roles of ECM components in the spreading of pathological protein aggregates in neurodegenerative diseases with the objective of identifying the current gaps in knowledge and stimulating further research in the field. This could potentially lead to the identification of druggable targets to slow down the spreading and/or progression of these pathologies.
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Affiliation(s)
- Edoardo Moretto
- Institute of Neuroscience, National Research Council, CNR, Milan, Italy
- UK Dementia Research Institute, University College London, London, United Kingdom
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, United Kingdom
- *Correspondence: Edoardo Moretto,
| | - Skye Stuart
- UK Dementia Research Institute, University College London, London, United Kingdom
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Sunaina Surana
- UK Dementia Research Institute, University College London, London, United Kingdom
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, United Kingdom
- UCL Queen Square Motor Neuron Disease Centre, University College London, London, United Kingdom
| | - Jose Norberto S. Vargas
- UK Dementia Research Institute, University College London, London, United Kingdom
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, United Kingdom
- UCL Queen Square Motor Neuron Disease Centre, University College London, London, United Kingdom
| | - Giampietro Schiavo
- UK Dementia Research Institute, University College London, London, United Kingdom
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London, United Kingdom
- UCL Queen Square Motor Neuron Disease Centre, University College London, London, United Kingdom
- Giampietro Schiavo,
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12
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Shadfar S, Brocardo M, Atkin JD. The Complex Mechanisms by Which Neurons Die Following DNA Damage in Neurodegenerative Diseases. Int J Mol Sci 2022; 23:ijms23052484. [PMID: 35269632 PMCID: PMC8910227 DOI: 10.3390/ijms23052484] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 02/12/2022] [Accepted: 02/17/2022] [Indexed: 01/18/2023] Open
Abstract
Human cells are exposed to numerous exogenous and endogenous insults every day. Unlike other molecules, DNA cannot be replaced by resynthesis, hence damage to DNA can have major consequences for the cell. The DNA damage response contains overlapping signalling networks that repair DNA and hence maintain genomic integrity, and aberrant DNA damage responses are increasingly described in neurodegenerative diseases. Furthermore, DNA repair declines during aging, which is the biggest risk factor for these conditions. If unrepaired, the accumulation of DNA damage results in death to eliminate cells with defective genomes. This is particularly important for postmitotic neurons because they have a limited capacity to proliferate, thus they must be maintained for life. Neuronal death is thus an important process in neurodegenerative disorders. In addition, the inability of neurons to divide renders them susceptible to senescence or re-entry to the cell cycle. The field of cell death has expanded significantly in recent years, and many new mechanisms have been described in various cell types, including neurons. Several of these mechanisms are linked to DNA damage. In this review, we provide an overview of the cell death pathways induced by DNA damage that are relevant to neurons and discuss the possible involvement of these mechanisms in neurodegenerative conditions.
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Affiliation(s)
- Sina Shadfar
- Centre for Motor Neuron Disease Research, Macquarie Medical School, Macquarie University, Sydney, NSW 2109, Australia; (S.S.); (M.B.)
| | - Mariana Brocardo
- Centre for Motor Neuron Disease Research, Macquarie Medical School, Macquarie University, Sydney, NSW 2109, Australia; (S.S.); (M.B.)
| | - Julie D. Atkin
- Centre for Motor Neuron Disease Research, Macquarie Medical School, Macquarie University, Sydney, NSW 2109, Australia; (S.S.); (M.B.)
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne, VIC 3086, Australia
- Correspondence:
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13
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De Marco G, Lomartire A, Manera U, Canosa A, Grassano M, Casale F, Fuda G, Salamone P, Rinaudo MT, Colombatto S, Moglia C, Chiò A, Calvo A. Effects of intracellular calcium accumulation on proteins encoded by the major genes underlying amyotrophic lateral sclerosis. Sci Rep 2022; 12:395. [PMID: 35013445 PMCID: PMC8748718 DOI: 10.1038/s41598-021-04267-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 12/16/2021] [Indexed: 12/12/2022] Open
Abstract
The aetiology of Amyotrophic Lateral Sclerosis (ALS) is still poorly understood. The discovery of genetic forms of ALS pointed out the mechanisms underlying this pathology, but also showed how complex these mechanisms are. Excitotoxicity is strongly suspected to play a role in ALS pathogenesis. Excitotoxicity is defined as neuron damage due to excessive intake of calcium ions (Ca2+) by the cell. This study aims to find a relationship between the proteins coded by the most relevant genes associated with ALS and intracellular Ca2+ accumulation. In detail, the profile of eight proteins (TDP-43, C9orf72, p62/sequestosome-1, matrin-3, VCP, FUS, SOD1 and profilin-1), was analysed in three different cell types induced to raise their cytoplasmic amount of Ca2+. Intracellular Ca2+ accumulation causes a decrease in the levels of TDP-43, C9orf72, matrin3, VCP, FUS, SOD1 and profilin-1 and an increase in those of p62/sequestosome-1. These events are associated with the proteolytic action of two proteases, calpains and caspases, as well as with the activation of autophagy. Interestingly, Ca2+ appears to both favour and hinder autophagy. Understanding how and why calpain-mediated proteolysis and autophagy, which are physiological processes, become pathological may elucidate the mechanisms responsible for ALS and help discover new therapeutic targets.
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Affiliation(s)
- Giovanni De Marco
- Department of Neuroscience, ALS Centre, "Rita Levi Montalcini", University of Turin, Via Cherasco 15, 10126, Turin, Italy. .,Neurology Unit 1, Azienda Ospedaliero-Universitaria Città della Salute e della Scienza di Torino, Via Cherasco 15, 10126, Turin, Italy.
| | - Annarosa Lomartire
- Department of Neuroscience, ALS Centre, "Rita Levi Montalcini", University of Turin, Via Cherasco 15, 10126, Turin, Italy
| | - Umberto Manera
- Department of Neuroscience, ALS Centre, "Rita Levi Montalcini", University of Turin, Via Cherasco 15, 10126, Turin, Italy
| | - Antonio Canosa
- Department of Neuroscience, ALS Centre, "Rita Levi Montalcini", University of Turin, Via Cherasco 15, 10126, Turin, Italy.,Neurology Unit 1, Azienda Ospedaliero-Universitaria Città della Salute e della Scienza di Torino, Via Cherasco 15, 10126, Turin, Italy
| | - Maurizio Grassano
- Department of Neuroscience, ALS Centre, "Rita Levi Montalcini", University of Turin, Via Cherasco 15, 10126, Turin, Italy
| | - Federico Casale
- Department of Neuroscience, ALS Centre, "Rita Levi Montalcini", University of Turin, Via Cherasco 15, 10126, Turin, Italy
| | - Giuseppe Fuda
- Department of Neuroscience, ALS Centre, "Rita Levi Montalcini", University of Turin, Via Cherasco 15, 10126, Turin, Italy
| | - Paolina Salamone
- Department of Neuroscience, ALS Centre, "Rita Levi Montalcini", University of Turin, Via Cherasco 15, 10126, Turin, Italy.,Neurology Unit 1, Azienda Ospedaliero-Universitaria Città della Salute e della Scienza di Torino, Via Cherasco 15, 10126, Turin, Italy
| | - Maria Teresa Rinaudo
- Department of Oncology, University of Turin, via Michelangelo 27/b, 10126, Turin, Italy
| | - Sebastiano Colombatto
- Department of Oncology, University of Turin, via Michelangelo 27/b, 10126, Turin, Italy
| | - Cristina Moglia
- Department of Neuroscience, ALS Centre, "Rita Levi Montalcini", University of Turin, Via Cherasco 15, 10126, Turin, Italy.,Neurology Unit 1, Azienda Ospedaliero-Universitaria Città della Salute e della Scienza di Torino, Via Cherasco 15, 10126, Turin, Italy
| | - Adriano Chiò
- Department of Neuroscience, ALS Centre, "Rita Levi Montalcini", University of Turin, Via Cherasco 15, 10126, Turin, Italy.,Neurology Unit 1, Azienda Ospedaliero-Universitaria Città della Salute e della Scienza di Torino, Via Cherasco 15, 10126, Turin, Italy.,Neuroscience Institute of Turin (NIT), Via Verdi, 8, 10124, Turin, Italy.,Institute of Cognitive Sciences and Technologies, C.N.R., Via S. Martino della Battaglia, 44, 00185, Rome, Italy
| | - Andrea Calvo
- Department of Neuroscience, ALS Centre, "Rita Levi Montalcini", University of Turin, Via Cherasco 15, 10126, Turin, Italy.,Neurology Unit 1, Azienda Ospedaliero-Universitaria Città della Salute e della Scienza di Torino, Via Cherasco 15, 10126, Turin, Italy.,Neuroscience Institute of Turin (NIT), Via Verdi, 8, 10124, Turin, Italy
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14
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de Mena L, Lopez-Scarim J, Rincon-Limas DE. TDP-43 and ER Stress in Neurodegeneration: Friends or Foes? Front Mol Neurosci 2021; 14:772226. [PMID: 34759799 PMCID: PMC8573113 DOI: 10.3389/fnmol.2021.772226] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 09/30/2021] [Indexed: 02/05/2023] Open
Abstract
Nuclear depletion, abnormal modification, and cytoplasmic aggregation of TAR DNA-binding protein 43 (TDP-43) are linked to a group of fatal neurodegenerative diseases called TDP-43 proteinopathies, which include amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Although our understanding of the physiological function of TDP-43 is rapidly advancing, the molecular mechanisms associated with its pathogenesis remain poorly understood. Accumulating evidence suggests that endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) are important players in TDP-43 pathology. However, while neurons derived from autopsied ALS and FTLD patients revealed TDP-43 deposits in the ER and displayed UPR activation, data originated from in vitro and in vivo TDP-43 models produced contradictory results. In this review, we will explore the complex interplay between TDP-43 pathology, ER stress, and the UPR by breaking down the evidence available in the literature and addressing the reasons behind these discrepancies. We also highlight underexplored areas and key unanswered questions in the field. A better synchronization and integration of methodologies, models, and mechanistic pathways will be crucial to discover the true nature of the TDP-43 and ER stress relationship and, ultimately, to uncover the full therapeutic potential of the UPR.
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Affiliation(s)
- Lorena de Mena
- Department of Neurology, McKnight Brain Institute, and Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
| | - Joshua Lopez-Scarim
- Department of Neurology, McKnight Brain Institute, and Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
| | - Diego E Rincon-Limas
- Department of Neurology, McKnight Brain Institute, and Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States.,Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, United States.,Genetics Institute, University of Florida, Gainesville, FL, United States
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15
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Suzuki H, Matsuoka M. Proline-arginine poly-dipeptide encoded by the C9orf72 repeat expansion inhibits adenosine deaminase acting on RNA. J Neurochem 2021; 158:753-765. [PMID: 34081786 DOI: 10.1111/jnc.15445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/25/2021] [Accepted: 05/31/2021] [Indexed: 12/20/2022]
Abstract
A GGGGCC hexanucleotide repeat expansion in the C9orf72 gene is linked to the pathogenesis of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (C9-ALS/FTD). Unconventional translation of the hexanucleotide repeat expansion generates five dipeptide repeat proteins (DPRs). The molecular mechanism underlying the DPR-linked neurotoxicity is under investigation. In this study, using cell-based models, we show that poly-proline-arginine DPR (poly-PR), the most neurotoxic DPR in vitro, binds to adenosine deaminase acting on RNA (ADAR)1p110 and ADAR2 and inhibits their RNA editing activity. We further show that poly-PR impairs cellular stress response that is mediated by ADAR1p110. These results together suggest that the poly-PR-mediated inhibition of the ADAR activity contributes to C9-ALS/FTD-linked neurotoxicity.
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Affiliation(s)
- Hiroaki Suzuki
- Department of Pharmacology, School of Medicine, Tokyo Medical University, Tokyo, Japan
| | - Masaaki Matsuoka
- Department of Pharmacology, School of Medicine, Tokyo Medical University, Tokyo, Japan
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16
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Chhangani D, Martín-Peña A, Rincon-Limas DE. Molecular, functional, and pathological aspects of TDP-43 fragmentation. iScience 2021; 24:102459. [PMID: 34013172 PMCID: PMC8113996 DOI: 10.1016/j.isci.2021.102459] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Transactive response DNA binding protein 43 (TDP-43) is a DNA/RNA binding protein involved in transcriptional regulation and RNA processing. It is linked to sporadic and familial amyotrophic lateral sclerosis and frontotemporal lobar degeneration. TDP-43 is predominantly nuclear, but it translocates to the cytoplasm under pathological conditions. Cytoplasmic accumulation, phosphorylation, ubiquitination and truncation of TDP-43 are the main hallmarks of TDP-43 proteinopathies. Among these processes, the pathways leading to TDP-43 fragmentation remain poorly understood. We review here the molecular and biochemical properties of several TDP-43 fragments, the mechanisms and factors mediating their production, and their potential role in disease progression. We also address the presence of TDP-43 C-terminal fragments in several neurological disorders, including Alzheimer's disease, and highlight their respective implications. Finally, we discuss features of animal models expressing TDP-43 fragments as well as recent therapeutic strategies to approach TDP-43 truncation.
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Affiliation(s)
- Deepak Chhangani
- Department of Neurology, McKnight Brain Institute, and Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32611, USA
| | - Alfonso Martín-Peña
- Department of Neurology, McKnight Brain Institute, and Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32611, USA
| | - Diego E Rincon-Limas
- Department of Neurology, McKnight Brain Institute, and Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL 32611, USA.,Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL 32611, USA.,Genetics Institute, University of Florida, Gainesville, FL 32611, USA
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17
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Harley J, Clarke BE, Patani R. The Interplay of RNA Binding Proteins, Oxidative Stress and Mitochondrial Dysfunction in ALS. Antioxidants (Basel) 2021; 10:antiox10040552. [PMID: 33918215 PMCID: PMC8066094 DOI: 10.3390/antiox10040552] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/26/2021] [Accepted: 03/31/2021] [Indexed: 12/12/2022] Open
Abstract
RNA binding proteins fulfil a wide number of roles in gene expression. Multiple mechanisms of RNA binding protein dysregulation have been implicated in the pathomechanisms of several neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). Oxidative stress and mitochondrial dysfunction also play important roles in these diseases. In this review, we highlight the mechanistic interplay between RNA binding protein dysregulation, oxidative stress and mitochondrial dysfunction in ALS. We also discuss different potential therapeutic strategies targeting these pathways.
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Affiliation(s)
- Jasmine Harley
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK;
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Benjamin E. Clarke
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK;
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Correspondence: (B.E.C.); (R.P.)
| | - Rickie Patani
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK;
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- National Hospital for Neurology and Neurosurgery, University College London NHS, London WC1N 3BG, UK
- Correspondence: (B.E.C.); (R.P.)
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18
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Lucini CB, Braun RJ. Mitochondrion-Dependent Cell Death in TDP-43 Proteinopathies. Biomedicines 2021; 9:376. [PMID: 33918437 PMCID: PMC8066287 DOI: 10.3390/biomedicines9040376] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/25/2021] [Accepted: 04/01/2021] [Indexed: 12/11/2022] Open
Abstract
In the last decade, pieces of evidence for TDP-43-mediated mitochondrial dysfunction in neurodegenerative diseases have accumulated. In patient samples, in vitro and in vivo models have shown mitochondrial accumulation of TDP-43, concomitantly with hallmarks of mitochondrial destabilization, such as increased production of reactive oxygen species (ROS), reduced level of oxidative phosphorylation (OXPHOS), and mitochondrial membrane permeabilization. Incidences of TDP-43-dependent cell death, which depends on mitochondrial DNA (mtDNA) content, is increased upon ageing. However, the molecular pathways behind mitochondrion-dependent cell death in TDP-43 proteinopathies remained unclear. In this review, we discuss the role of TDP-43 in mitochondria, as well as in mitochondrion-dependent cell death. This review includes the recent discovery of the TDP-43-dependent activation of the innate immunity cyclic GMP-AMP synthase/stimulator of interferon genes (cGAS/STING) pathway. Unravelling cell death mechanisms upon TDP-43 accumulation in mitochondria may open up new opportunities in TDP-43 proteinopathy research.
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Affiliation(s)
- Chantal B. Lucini
- Research Area Neurodegenerative Diseases, Center for Biosciences, Faculty of Medicine/Dental Medicine, Danube Private University, 3500 Krems an der Donau, Austria
| | - Ralf J. Braun
- Research Area Neurodegenerative Diseases, Center for Biosciences, Faculty of Medicine/Dental Medicine, Danube Private University, 3500 Krems an der Donau, Austria
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19
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Dafinca R, Barbagallo P, Talbot K. The Role of Mitochondrial Dysfunction and ER Stress in TDP-43 and C9ORF72 ALS. Front Cell Neurosci 2021; 15:653688. [PMID: 33867942 PMCID: PMC8047135 DOI: 10.3389/fncel.2021.653688] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/10/2021] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of the motor system with complex determinants, including genetic and non-genetic factors. Despite this heterogeneity, a key pathological signature is the mislocalization and aggregation of specific proteins in the cytoplasm, suggesting that convergent pathogenic mechanisms focusing on disturbances in proteostasis are important in ALS. In addition, many cellular processes have been identified as potentially contributing to disease initiation and progression, such as defects in axonal transport, autophagy, nucleocytoplasmic transport, ER stress, calcium metabolism, the unfolded protein response and mitochondrial function. Here we review the evidence from in vitro and in vivo models of C9ORF72 and TDP-43-related ALS supporting a central role in pathogenesis for endoplasmic reticulum stress, which activates an unfolded protein response (UPR), and mitochondrial dysfunction. Disruption in the finely tuned signaling between the ER and mitochondria through calcium ions may be a crucial trigger of mitochondrial deficits and initiate an apoptotic signaling cascade, thus acting as a point of convergence for multiple upstream disturbances of cellular homeostasis and constituting a potentially important therapeutic target.
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20
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Halloran M, Ragagnin AMG, Vidal M, Parakh S, Yang S, Heng B, Grima N, Shahheydari H, Soo KY, Blair I, Guillemin GJ, Sundaramoorthy V, Atkin JD. Amyotrophic lateral sclerosis-linked UBQLN2 mutants inhibit endoplasmic reticulum to Golgi transport, leading to Golgi fragmentation and ER stress. Cell Mol Life Sci 2020; 77:3859-3873. [PMID: 31802140 PMCID: PMC11105036 DOI: 10.1007/s00018-019-03394-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 10/28/2019] [Accepted: 11/22/2019] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are fatal neurodegenerative diseases that are related genetically and pathologically. Mutations in the UBQLN2 gene, encoding the ubiquitin-like protein ubiquilin2, are associated with familial ALS/FTD, but the pathophysiological mechanisms remain unclear. Here, we demonstrate that ALS/FTD UBQLN2 mutants P497H and P506T inhibit protein transport from the endoplasmic reticulum (ER) to the Golgi apparatus in neuronal cells. In addition, we observed that Sec31-positive ER exit sites are clustered in UBQLN2T487I patient spinal cord tissues. Both the ER-Golgi intermediate (ERGIC) compartment and the Golgi become disorganised and fragmented. This activates ER stress and inhibits ER-associated degradation. Hence, this study highlights perturbations in secretory protein trafficking and ER homeostasis as pathogenic mechanisms associated with ALS/FTD-associated forms of UBQLN2.
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Affiliation(s)
- Mark Halloran
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Audrey M G Ragagnin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Marta Vidal
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Sonam Parakh
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Shu Yang
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Benjamin Heng
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Natalie Grima
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Hamideh Shahheydari
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Kai-Ying Soo
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Ian Blair
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Gilles J Guillemin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Vinod Sundaramoorthy
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Julie D Atkin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia.
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne, Australia.
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21
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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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22
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Chami AA, Beltran S, Corcia P, Andres CR, Laumonnier F, Blasco H, Vourc'H P. A novel mutation in the cleavage site N291 of TDP-43 protein in a familial case of amyotrophic lateral sclerosis. Amyotroph Lateral Scler Frontotemporal Degener 2020; 21:463-466. [PMID: 32301341 DOI: 10.1080/21678421.2020.1752243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Cytoplasmic aggregation of TAR-DNA binding protein (TDP-43) in Amyotrophic Lateral Sclerosis (ALS) and fronto-temporal lobar dementia (FTLD) is associated with post-translational modifications (PTM) and delocalization. Studies on postmortem brains of ALS and FTLD patients showed the existence of TDP-43 fragments that end at position N291. We report a new heterozygous mutation p.N291H in a familial case of ALS. Expression of the mutant protein in cell lines and primary motor neurons induces aggregate formation in the cytoplasm and reduces cell viability. The discovery of mutations at cleavage sites in TDP-43 in patients, which we reviewed here, is valuable for understanding the true role of the various TDP-43 fragments identified in patients and thus, for developing effective targeted therapies for ALS and FTLD treatment.
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Affiliation(s)
- Anna A Chami
- UMR 1253, iBRAIN, Université de Tours, Inserm, Tours, France
| | - Stéphane Beltran
- UMR 1253, iBRAIN, Université de Tours, Inserm, Tours, France.,CHU de Tours, Service de Neurologie, Tours, France
| | - Philippe Corcia
- UMR 1253, iBRAIN, Université de Tours, Inserm, Tours, France.,CHU de Tours, Service de Neurologie, Tours, France
| | - Christian R Andres
- UMR 1253, iBRAIN, Université de Tours, Inserm, Tours, France.,CHU de Tours, Service de Biochimie et Biologie Moléculaire, Tours, France
| | | | - Hélène Blasco
- UMR 1253, iBRAIN, Université de Tours, Inserm, Tours, France.,CHU de Tours, Service de Biochimie et Biologie Moléculaire, Tours, France
| | - Patrick Vourc'H
- UMR 1253, iBRAIN, Université de Tours, Inserm, Tours, France.,CHU de Tours, Service de Biochimie et Biologie Moléculaire, Tours, France
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23
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Girdhar A, Bharathi V, Tiwari VR, Abhishek S, Deeksha W, Mahawar US, Raju G, Singh SK, Prabusankar G, Rajakumara E, Patel BK. Computational insights into mechanism of AIM4-mediated inhibition of aggregation of TDP-43 protein implicated in ALS and evidence for in vitro inhibition of liquid-liquid phase separation (LLPS) of TDP-432C-A315T by AIM4. Int J Biol Macromol 2020; 147:117-130. [DOI: 10.1016/j.ijbiomac.2020.01.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/04/2020] [Accepted: 01/04/2020] [Indexed: 12/12/2022]
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24
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François-Moutal L, Perez-Miller S, Scott DD, Miranda VG, Mollasalehi N, Khanna M. Structural Insights Into TDP-43 and Effects of Post-translational Modifications. Front Mol Neurosci 2019; 12:301. [PMID: 31920533 PMCID: PMC6934062 DOI: 10.3389/fnmol.2019.00301] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/25/2019] [Indexed: 12/12/2022] Open
Abstract
Transactive response DNA binding protein (TDP-43) is a key player in neurodegenerative diseases. In this review, we have gathered and presented structural information on the different regions of TDP-43 with high resolution structures available. A thorough understanding of TDP-43 structure, effect of modifications, aggregation and sites of localization is necessary as we develop therapeutic strategies targeting TDP-43 for neurodegenerative diseases. We discuss how different domains as well as post-translational modification may influence TDP-43 overall structure, aggregation and droplet formation. The primary aim of the review is to utilize structural insights as we develop an understanding of the deleterious behavior of TDP-43 and highlight locations of established and proposed post-translation modifications. TDP-43 structure and effect on localization is paralleled by many RNA-binding proteins and this review serves as an example of how structure may be modulated by numerous compounding elements.
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Affiliation(s)
- Liberty François-Moutal
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
| | - Samantha Perez-Miller
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
| | - David D Scott
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
| | - Victor G Miranda
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
| | - Niloufar Mollasalehi
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States.,Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States
| | - May Khanna
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
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25
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C9-ALS/FTD-linked proline-arginine dipeptide repeat protein associates with paraspeckle components and increases paraspeckle formation. Cell Death Dis 2019; 10:746. [PMID: 31582731 PMCID: PMC6776546 DOI: 10.1038/s41419-019-1983-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 08/29/2019] [Accepted: 09/16/2019] [Indexed: 12/12/2022]
Abstract
A GGGGCC hexanucleotide repeat expansion in the C9ORF72 gene has been identified as the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. The repeat expansion undergoes unconventional translation to produce five dipeptide repeat proteins (DPRs). Although DPRs are thought to be neurotoxic, the molecular mechanism underlying the DPR-caused neurotoxicity has not been fully elucidated. The current study shows that poly-proline-arginine (poly-PR), the most toxic DPR in vitro, binds to and up-regulates nuclear paraspeckle assembly transcript 1 (NEAT1) that plays an essential role as a scaffold non-coding RNA during the paraspeckle formation. The CRISPR-assisted up-regulation of endogenous NEAT1 causes neurotoxicity. We also show that the poly-PR modulates the function of several paraspeckle-localizing heterogeneous nuclear ribonucleoproteins. Furthermore, dysregulated expression of TAR DNA-binding protein 43 (TDP-43) up-regulates NEAT1 expression and induces neurotoxicity. These results suggest that the increase in the paraspeckle formation may be involved in the poly-PR- and TDP-43-mediated neurotoxicity.
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Sugai A, Kato T, Koyama A, Koike Y, Konno T, Ishihara T, Onodera O. Non-genetically modified models exhibit TARDBP mRNA increase due to perturbed TDP-43 autoregulation. Neurobiol Dis 2019; 130:104534. [PMID: 31310801 DOI: 10.1016/j.nbd.2019.104534] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 06/22/2019] [Accepted: 07/12/2019] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by accumulation of fragmented insoluble TDP-43 and loss of TDP-43 from the nucleus. Increased expression of exogenous TARDBP (encoding TDP-43) induces TDP-43 pathology and cytotoxicity, suggesting the involvement of aberrant expression of TDP-43 in the pathogenesis of ALS. In normal conditions, however, the amount of TDP-43 is tightly regulated by the autoregulatory mechanism involving alternative splicing of TARDBP mRNA. To investigate the influence of autoregulation dysfunction, we inhibited the splicing of cryptic intron 6 using antisense oligonucleotides in vivo. This inhibition doubled the Tardbp mRNA expression, increased the fragmented insoluble TDP-43, and reduced the number of motor neurons in the mouse spinal cord. In human induced pluripotent stem cell-derived neurons, the splicing inhibition of intron 6 increased TARDBP mRNA and decreased nuclear TDP-43. These non-genetically modified models exhibiting rise in the TARDBP mRNA levels suggest that TDP-43 autoregulation turbulence might be linked to the pathogenesis of ALS.
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Affiliation(s)
- Akihiro Sugai
- Department of Neurology, Clinical Neuroscience Branch, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Taisuke Kato
- Department of System Pathology for Neurological Disorders, Brain Science Branch, Center for Bioresource-based Research, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Akihide Koyama
- Division of Legal Medicine, Graduate School of Medicine and Dental Science, Niigata University, Niigata 951-8585, Japan
| | - Yuka Koike
- Department of Neurology, Clinical Neuroscience Branch, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Takuya Konno
- Department of Neurology, Clinical Neuroscience Branch, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Tomohiko Ishihara
- Department of Molecular Neuroscience, Resource Branch for Brain Disease Research, Center for Bioresource-based Research, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Osamu Onodera
- Department of Neurology, Clinical Neuroscience Branch, Brain Research Institute, Niigata University, Niigata 951-8585, Japan.
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27
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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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28
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Chi H, Chang HY, Sang TK. Neuronal Cell Death Mechanisms in Major Neurodegenerative Diseases. Int J Mol Sci 2018; 19:E3082. [PMID: 30304824 PMCID: PMC6213751 DOI: 10.3390/ijms19103082] [Citation(s) in RCA: 210] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/03/2018] [Accepted: 10/05/2018] [Indexed: 12/14/2022] Open
Abstract
Neuronal cell death in the central nervous system has always been a challenging process to decipher. In normal physiological conditions, neuronal cell death is restricted in the adult brain, even in aged individuals. However, in the pathological conditions of various neurodegenerative diseases, cell death and shrinkage in a specific region of the brain represent a fundamental pathological feature across different neurodegenerative diseases. In this review, we will briefly go through the general pathways of cell death and describe evidence for cell death in the context of individual common neurodegenerative diseases, discussing our current understanding of cell death by connecting with renowned pathogenic proteins, including Tau, amyloid-beta, alpha-synuclein, huntingtin and TDP-43.
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Affiliation(s)
- Hao Chi
- Institute of Biotechnology, National Tsing Hua University, Hsinchu City 30013, Taiwan.
| | - Hui-Yun Chang
- Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu City 30013, Taiwan.
| | - Tzu-Kang Sang
- Institute of Biotechnology, National Tsing Hua University, Hsinchu City 30013, Taiwan.
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29
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Suzuki H, Shibagaki Y, Hattori S, Matsuoka M. The proline-arginine repeat protein linked to C9-ALS/FTD causes neuronal toxicity by inhibiting the DEAD-box RNA helicase-mediated ribosome biogenesis. Cell Death Dis 2018; 9:975. [PMID: 30250194 PMCID: PMC6155127 DOI: 10.1038/s41419-018-1028-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/16/2018] [Accepted: 09/04/2018] [Indexed: 12/31/2022]
Abstract
A GGGGCC repeat expansion in the C9ORF72 gene has been identified as the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. The repeat expansion undergoes unconventional translation to produce dipeptide repeat (DPR) proteins. Although it has been reported that DPR proteins cause neurotoxicity, the underlying mechanism has not been fully elucidated. In this study, we have first confirmed that proline-arginine repeat protein (poly-PR) reduces levels of ribosomal RNA and causes neurotoxicity and found that the poly-PR-induced neurotoxicity is repressed by the acceleration of ribosomal RNA synthesis. These results suggest that the poly-PR-induced inhibition of ribosome biogenesis contributes to the poly-PR-induced neurotoxicity. We have further identified DEAD-box RNA helicases as poly-PR-binding proteins, the functions of which are inhibited by poly-PR. The enforced reduction in the expression of DEAD-box RNA helicases causes impairment of ribosome biogenesis and neuronal cell death. These results together suggest that poly-PR causes neurotoxicity by inhibiting the DEAD-box RNA helicase-mediated ribosome biogenesis.
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Affiliation(s)
- Hiroaki Suzuki
- Department of Pharmacology, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, 160-8402, Japan
| | - Yoshio Shibagaki
- Division of Biochemistry, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Seisuke Hattori
- Division of Biochemistry, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Masaaki Matsuoka
- Department of Pharmacology, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, 160-8402, Japan.
- Department of Dermatological Neuroscience, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo, 160-8402, Japan.
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30
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Hans F, Eckert M, von Zweydorf F, Gloeckner CJ, Kahle PJ. Identification and characterization of ubiquitinylation sites in TAR DNA-binding protein of 43 kDa (TDP-43). J Biol Chem 2018; 293:16083-16099. [PMID: 30120199 DOI: 10.1074/jbc.ra118.003440] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 08/14/2018] [Indexed: 12/13/2022] Open
Abstract
TAR DNA-binding protein of 43 kDa (TDP-43) forms pathological aggregates in neurodegenerative diseases, particularly in certain forms of frontotemporal dementia and amyotrophic lateral sclerosis. Pathological modifications of TDP-43 include proteolytic fragmentation, phosphorylation, and ubiquitinylation. A pathognomonic TDP-43 C-terminal fragment (CTF) spanning amino acids 193-414 contains only four lysine residues that could be potentially ubiquitinylated. Here, serial mutagenesis of these four lysines to arginine revealed that not a single residue is responsible for the ubiquitinylation of mCherry-tagged CTF. Removal of all four lysines was necessary to suppress ubiquitinylation. Interestingly, Lys-408 substitution enhanced the pathological phosphorylation of the immediately adjacent serine residues 409/410 in the context of mCherry-CTF. Thus, Lys-408 ubiquitinylation appears to hinder Ser-409/410 phosphorylation in TDP-43 CTF. However, we did not observe the same effect for full-length TDP-43. We extended the mutagenesis study to full-length TDP-43 and performed MS. Ubiquitinylated lysine residues were identified in the nuclear localization sequence (NLS; Lys-84 and Lys-95) and RNA-binding region (mostly Lys-160, Lys-181, and Lys-263). Mutagenesis of Lys-84 confirmed its importance as the major determinant for nuclear import, whereas Lys-95 mutagenesis did not significantly affect TDP-43's nucleo-cytoplasmic distribution, solubility, aggregation, and RNA-processing activities. Nevertheless, the K95A mutant had significantly reduced Ser-409/410 phosphorylation, emphasizing the suspected interplay between TDP-43 ubiquitinylation and phosphorylation. Collectively, our analysis of TDP-43 ubiquitinylation sites indicates that the NLS residues Lys-84 and Lys-95 have more prominent roles in TDP-43 function than the more C-terminal lysines and suggests a link between specific ubiquitinylation events and pathological TDP-43 phosphorylation.
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Affiliation(s)
- Friederike Hans
- From the German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen and.,the Hertie Institute for Clinical Brain Research, Department of Neurodegeneration, and
| | - Marita Eckert
- From the German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen and.,the Hertie Institute for Clinical Brain Research, Department of Neurodegeneration, and
| | - Felix von Zweydorf
- From the German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen and
| | - Christian Johannes Gloeckner
- From the German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen and.,the Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, 72076 Tübingen, Germany
| | - Philipp J Kahle
- From the German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen and .,the Hertie Institute for Clinical Brain Research, Department of Neurodegeneration, and
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31
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Raloxifene, a promising estrogen replacement, limits TDP-25 cell death by enhancing autophagy and suppressing apoptosis. Brain Res Bull 2018; 140:281-290. [DOI: 10.1016/j.brainresbull.2018.05.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/29/2018] [Accepted: 05/21/2018] [Indexed: 12/11/2022]
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32
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Vogt MA, Ehsaei Z, Knuckles P, Higginbottom A, Helmbrecht MS, Kunath T, Eggan K, Williams LA, Shaw PJ, Wurst W, Floss T, Huber AB, Taylor V. TDP-43 induces p53-mediated cell death of cortical progenitors and immature neurons. Sci Rep 2018; 8:8097. [PMID: 29802307 PMCID: PMC5970242 DOI: 10.1038/s41598-018-26397-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 05/09/2018] [Indexed: 12/13/2022] Open
Abstract
TAR DNA-binding protein 43 (TDP-43) is a key player in neurodegenerative diseases including frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Accumulation of TDP-43 is associated with neuronal death in the brain. How increased and disease-causing mutant forms of TDP-43 induce cell death remains unclear. Here we addressed the role of TDP-43 during neural development and show that reduced TDP-43 causes defects in neural stem/progenitor cell proliferation but not cell death. However, overexpression of wild type and TDP-43A315T proteins induce p53-dependent apoptosis of neural stem/progenitors and human induced pluripotent cell (iPS)-derived immature cortical neurons. We show that TDP-43 induces expression of the proapoptotic BH3-only genes Bbc3 and Bax, and that p53 inhibition rescues TDP-43 induced cell death of embryonic mouse, and human cortical neurons, including those derived from TDP-43G298S ALS patient iPS cells. Hence, an increase in wild type and mutant TDP-43 induces p53-dependent cell death in neural progenitors developing neurons and this can be rescued. These findings may have important implications for accumulated or mutant TDP-43 induced neurodegenerative diseases.
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Affiliation(s)
- Miriam A Vogt
- Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058, Basel, Switzerland.,Ludwig-Maximilians University Munich, Feodor-Lynen-Strasse 17, 81377, München, Germany
| | - Zahra Ehsaei
- Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058, Basel, Switzerland
| | - Philip Knuckles
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058, Basel, Switzerland
| | - Adrian Higginbottom
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385A Glossop Road, Sheffield, S10 2HQ, UK
| | | | - Tilo Kunath
- MRC Centre for Regenerative Medicine, The University of Edinburgh, 5 Little France Drive, Edinburgh, EH16 4UU, UK
| | - Kevin Eggan
- Harvard Stem Cell Institute, Harvard University, Howard Hughes Medical Institute, 7 Divinity Avenue, Cambridge, MA, 02138, USA
| | - Luis A Williams
- Harvard Stem Cell Institute, Harvard University, Howard Hughes Medical Institute, 7 Divinity Avenue, Cambridge, MA, 02138, USA
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385A Glossop Road, Sheffield, S10 2HQ, UK
| | - Wolfgang Wurst
- Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
| | - Thomas Floss
- Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
| | - Andrea B Huber
- Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany.,ETH Zurich, Department of Biosystems Science and Engineering, Mattenstrasse 26, 4058, Basel, Switzerland
| | - Verdon Taylor
- Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058, Basel, Switzerland.
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33
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Sun L, Zhang K, Zhai W, Li H, Shen H, Yu Z, Chen G. TAR DNA Binding Protein-43 Loss of Function Induced by Phosphorylation at S409/410 Blocks Autophagic Flux and Participates in Secondary Brain Injury After Intracerebral Hemorrhage. Front Cell Neurosci 2018; 12:79. [PMID: 29623031 PMCID: PMC5874314 DOI: 10.3389/fncel.2018.00079] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 03/07/2018] [Indexed: 11/13/2022] Open
Abstract
This study aimed to determine the role of TAR DNA binding protein-43 (TDP-43) in intracerebral hemorrhage (ICH)-induced secondary brain injury (SBI) and its underlying mechanisms. After ICH, expression of TDP-43 in the nucleus was significantly decreased, and its expression in the cytoplasm increased both in vivo and in vitro, which indicates that TDP-43 translocates from the nucleus to the cytoplasm during SBI after ICH. In addition, mutations at S409/410 of TDP-43 could inhibit its phosphorylation, attenuate nuclear loss, and abolish the increase in neuronal apoptosis in the subcortex. Inhibition of TDP-43 phosphorylation attenuated ICH-induced downregulation of mTOR activity and dynactin1 expression, which may relieve blocking of autophagosome-lysosome fusion and the increase of autophagosomal and lysosomal biogenesis induced by ICH. However, knockdown of TDP-43 could worsen ICH-induced SBI. Furthermore, TDP-43 could be dephosphorylated by calcineurin (CN), and CN activity was increased by OxyHb treatment. In conclusion, this study demonstrated that TDP-43 loss-of-function by phosphorylation at S409/410 may block autophagosome-lysosome fusion and induce elevation of LC3II and p62 levels by inhibiting the activity of mTOR and expression of dynactin1. This mechanism may play an important role in ICH-induced SBI, and TDP-43 may be a potential therapeutic target.
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Affiliation(s)
- Liang Sun
- Department of Neurosurgery, Huai'an First People's Hospital, Nanjing Medical University, Huai'an, China.,Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Kai Zhang
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Weiwei Zhai
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Haiying Li
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Haitao Shen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Zhengquan Yu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Gang Chen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, China
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34
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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: 135] [Impact Index Per Article: 22.5] [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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35
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Zeineddine R, Farrawell NE, Lambert-Smith IA, Yerbury JJ. Addition of exogenous SOD1 aggregates causes TDP-43 mislocalisation and aggregation. Cell Stress Chaperones 2017; 22:893-902. [PMID: 28560609 PMCID: PMC5655364 DOI: 10.1007/s12192-017-0804-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 04/24/2017] [Accepted: 04/28/2017] [Indexed: 12/11/2022] Open
Abstract
ALS is characterised by a focal onset of motor neuron loss, followed by contiguous outward spreading of pathology throughout the nervous system, resulting in paralysis and death generally within a few years after diagnosis. The aberrant release and uptake of toxic proteins including SOD1 and TDP-43 and their subsequent propagation, accumulation and deposition in motor neurons may explain such a pattern of pathology. Previous work has suggested that the internalization of aggregates triggers stress granule formation. Given the close association of stress granules and TDP-43, we wondered whether internalisation of SOD1 aggregates stimulated TDP-43 cytosolic aggregate structures. Addition of recombinant mutant G93A SOD1 aggregates to NSC-34 cells was found to trigger a rapid shift of TDP-43 to the cytoplasm where it was still accumulated after 48 h. In addition, SOD1 aggregates also triggered cleavage of TDP-43 into fragments including a 25 kDa fragment. Collectively, this study suggests a role for protein aggregate uptake in TDP-43 pathology.
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Affiliation(s)
- Rafaa Zeineddine
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
- School of Biological Sciences, Science Medicine and Health Faculty, University of Wollongong, Wollongong, NSW, Australia
| | - Natalie E Farrawell
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
- School of Biological Sciences, Science Medicine and Health Faculty, University of Wollongong, Wollongong, NSW, Australia
| | - Isabella A Lambert-Smith
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
- School of Biological Sciences, Science Medicine and Health Faculty, University of Wollongong, Wollongong, NSW, Australia
| | - Justin J Yerbury
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.
- School of Biological Sciences, Science Medicine and Health Faculty, University of Wollongong, Wollongong, NSW, Australia.
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36
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Zhuang J, Wen X, Zhang YQ, Shan Q, Zhang ZF, Zheng GH, Fan SH, Li MQ, Wu DM, Hu B, Lu J, Zheng YL. TDP-43 upregulation mediated by the NLRP3 inflammasome induces cognitive impairment in 2 2',4,4'-tetrabromodiphenyl ether (BDE-47)-treated mice. Brain Behav Immun 2017; 65:99-110. [PMID: 28532818 DOI: 10.1016/j.bbi.2017.05.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/10/2017] [Accepted: 05/19/2017] [Indexed: 10/19/2022] Open
Abstract
It is now commonly known that exposure to polybrominated diphenyl ethers (PBDEs) may cause neurotoxicity and cognitive deficits in children as well as adults, but the underlying mechanisms are still not clear. In the present study, we aimed to elucidate the potential underlying mechanism of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47)-induced neurotoxicity and cognitive impairment. Our results showed that BDE-47-treated mice exhibited impaired cognition and robust upregulation of nuclear TDP-43 in the hippocampus. Hippocampus-specific TDP-43 knockdown attenuated hippocampal apoptosis, restored synaptic protein levels and thus improved cognitive dysfunction in BDE-47-treated mice. Furthermore, our data demonstrated that NLRP3 inflammasome activation played a distinct role in the upregulation of nuclear TDP-43 by downregulating Parkin in the hippocampus of BDE-47-treated mice. Knocking down NLRP3 in the hippocampus or inhibiting caspase 1 activity in BDE-47-treated mice effectively increased Parkin expression in the hippocampus, which decreased the levels of nuclear TDP-43 and ultimately abrogated TDP-43-induced neurotoxic effects. Taken together, our data indicate that TDP-43 upregulation mediated by NLRP3 inflammasome activation via Parkin downregulation in the hippocampus induces cognitive decline in BDE-47-treated mice, and suggest that inhibition of NLRP3 or TDP-43 may be a potential strategy for the prevention or treatment of cognitive impairment in BDE-47-induced neurotoxicity and brain diseases.
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Affiliation(s)
- Juan Zhuang
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, Jiangsu Province, PR China; Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China; Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around Hongze Lake, School of Life Science, Huaiyin Normal University, 111 Changjiang Road, Huaian 223300, Jiangsu Province, PR China
| | - Xin Wen
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Yan-Qiu Zhang
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, Jiangsu Province, PR China
| | - Qun Shan
- School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, Jiangsu Province, PR China; Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Zi-Feng Zhang
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Gui-Hong Zheng
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Shao-Hua Fan
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Meng-Qiu Li
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Dong-Mei Wu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Bin Hu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China
| | - Jun Lu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China.
| | - Yuan-Lin Zheng
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, 101 Shanghai Road, Xuzhou 221116, Jiangsu Province, PR China.
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Wobst HJ, Delsing L, Brandon NJ, Moss SJ. Truncation of the TAR DNA-binding protein 43 is not a prerequisite for cytoplasmic relocalization, and is suppressed by caspase inhibition and by introduction of the A90V sequence variant. PLoS One 2017; 12:e0177181. [PMID: 28510586 PMCID: PMC5433705 DOI: 10.1371/journal.pone.0177181] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 04/23/2017] [Indexed: 12/12/2022] Open
Abstract
The RNA-binding and -processing protein TAR DNA-binding protein 43 (TDP-43) is heavily linked to the underlying causes and pathology of neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration. In these diseases, TDP-43 is mislocalized, hyperphosphorylated, ubiquitinated, aggregated and cleaved. The importance of TDP-43 cleavage in the disease pathogenesis is still poorly understood. Here we detail the use of D-sorbitol as an exogenous stressor that causes TDP-43 cleavage in HeLa cells, resulting in a 35 kDa truncated product that accumulates in the cytoplasm within one hour of treatment. We confirm that the formation of this 35 kDa cleavage product is mediated by the activation of caspases. Inhibition of caspases blocks the cleavage of TDP-43, but does not prevent the accumulation of full-length protein in the cytoplasm. Using D-sorbitol as a stressor and caspase activator, we also demonstrate that the A90V variant of TDP-43, which lies adjacent to the caspase cleavage site within the nuclear localization sequence of TDP-43, confers partial resistance against caspase-mediated generation of the 35 kDa cleavage product.
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Affiliation(s)
- Heike J. Wobst
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Tufts University, Boston, MA, United States of America
| | - Louise Delsing
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Tufts University, Boston, MA, United States of America
- AstraZeneca, Discovery Science, Innovative Medicines and Early Development Biotech Unit, Mölndal, Sweden
| | - Nicholas J. Brandon
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Tufts University, Boston, MA, United States of America
- AstraZeneca, Neuroscience, Innovative Medicines and Early Development, Waltham, MA, United States of America
| | - Stephen J. Moss
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Tufts University, Boston, MA, United States of America
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States of America
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38
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Webster CP, Smith EF, Shaw PJ, De Vos KJ. Protein Homeostasis in Amyotrophic Lateral Sclerosis: Therapeutic Opportunities? Front Mol Neurosci 2017; 10:123. [PMID: 28512398 PMCID: PMC5411428 DOI: 10.3389/fnmol.2017.00123] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 04/11/2017] [Indexed: 12/11/2022] Open
Abstract
Protein homeostasis (proteostasis), the correct balance between production and degradation of proteins, is essential for the health and survival of cells. Proteostasis requires an intricate network of protein quality control pathways (the proteostasis network) that work to prevent protein aggregation and maintain proteome health throughout the lifespan of the cell. Collapse of proteostasis has been implicated in the etiology of a number of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), the most common adult onset motor neuron disorder. Here, we review the evidence linking dysfunctional proteostasis to the etiology of ALS and discuss how ALS-associated insults affect the proteostasis network. Finally, we discuss the potential therapeutic benefit of proteostasis network modulation in ALS.
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Affiliation(s)
- Christopher P Webster
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - Emma F Smith
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - Kurt J De Vos
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
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39
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Suzuki H, Matsuoka M. hnRNPA1 autoregulates its own mRNA expression to remain non-cytotoxic. Mol Cell Biochem 2016; 427:123-131. [PMID: 28000042 DOI: 10.1007/s11010-016-2904-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 12/03/2016] [Indexed: 01/03/2023]
Abstract
Heterogeneous nuclear ribonucleoprotein (hnRNP)A1, a member of the hnRNP family, is involved in a variety of RNA metabolisms. The hnRNPA1 expression is altered in some human diseases and mutations of the hnRNPA1 gene cause amyotrophic lateral sclerosis and multisystem proteinopathy. It has been therefore assumed that the dysregulation of hnRNPA1 is linked to the pathogenesis of the diseases. However, the mechanism underlying the regulation of the hnRNPA1 expression remains unknown. In this study, using cell-based models, we have found that hnRNPA1 negatively regulates its own mRNA expression by inhibiting the intron10 splicing of hnRNPA1 pre-mRNA. This mechanism likely serves as an autoregulation of the hnRNPA1 expression. We have also found that a low-grade excess of hnRNPA1 expression causes cytotoxicity by activating the mitochondrial apoptosis pathway. Collectively, these data suggest that the level of hnRNPA1 is strictly controlled to be within a certain range by the mRNA autoregulation in the physiological condition so that the cytotoxicity-causative alteration of hnRNPA1 expression does not take place.
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Affiliation(s)
- Hiroaki Suzuki
- Department of Pharmacology, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-Ku, Tokyo, 160-8402, Japan
| | - Masaaki Matsuoka
- Department of Pharmacology, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-Ku, Tokyo, 160-8402, Japan. .,Department of Dermatological Neuroscience, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-Ku, Tokyo, 160-8402, Japan.
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40
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Nagahara Y, Shimazawa M, Ohuchi K, Ito J, Takahashi H, Tsuruma K, Kakita A, Hara H. GPNMB ameliorates mutant TDP-43-induced motor neuron cell death. J Neurosci Res 2016; 95:1647-1665. [PMID: 27935101 DOI: 10.1002/jnr.23999] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/15/2016] [Accepted: 11/21/2016] [Indexed: 12/11/2022]
Abstract
Glycoprotein nonmetastatic melanoma protein B (GPNMB) aggregates are observed in the spinal cord of amyotrophic lateral sclerosis (ALS) patients, but the detailed localization is still unclear. Mutations of transactive response DNA binding protein 43kDa (TDP-43) are associated with neurodegenerative diseases including ALS. In this study, we evaluated the localization of GPNMB aggregates in the spinal cord of ALS patients and the effect of GPNMB against mutant TDP-43 induced motor neuron cell death. GPNMB aggregates were not localized in the glial fibrillary acidic protein (GFAP)-positive astrocyte and ionized calcium binding adaptor molecule-1 (Iba1)-positive microglia. GPNMB aggregates were localized in the microtubule-associated protein 2 (MAP-2)-positive neuron and neurofilament H non-phosphorylated (SMI-32)-positive neuron, and these were co-localized with TDP-43 aggregates in the spinal cord of ALS patients. Mock or TDP-43 (WT, M337V, and A315T) plasmids were transfected into mouse motor neuron cells (NSC34). The expression level of GPNMB was increased by transfection of mutant TDP-43 plasmids. Recombinant GPNMB ameliorated motor neuron cell death induced by transfection of mutant TDP-43 plasmids and serum-free stress. Furthermore, the expression of phosphorylated ERK1/2 and phosphorylated Akt were decreased by this stress, and these expressions were increased by recombinant GPNMB. These results indicate that GPNMB has protective effects against mutant TDP-43 stress via activating the ERK1/2 and Akt pathways, and GPNMB may be a therapeutic target for TDP-43 proteinopathy in familial and sporadic ALS. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Yuki Nagahara
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Masamitsu Shimazawa
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Kazuki Ohuchi
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Junko Ito
- Department of Pathology, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Hitoshi Takahashi
- Department of Pathology, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Kazuhiro Tsuruma
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, University of Niigata, Niigata, Japan
| | - Hideaki Hara
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
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41
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Mouhid Al-Achbili L, Moreno-Ortega AJ, Matías-Guiu J, Cano-Abad MF, Ruiz-Nuño A. ITH33/IQM9.21 provides neuroprotection in a novel ALS model based on TDP-43 and Na +/Ca 2+ overload induced by VTD. Neurosci Lett 2016; 633:28-32. [PMID: 27619542 DOI: 10.1016/j.neulet.2016.09.009] [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: 07/05/2016] [Revised: 08/30/2016] [Accepted: 09/07/2016] [Indexed: 12/11/2022]
Abstract
Therapeutic options for amyotrophic lateral sclerosis (ALS) are scarce and controversial. Although the aetiology of neuronal vulnerability is unknown, growing evidence supports a complex network in which multiple toxicity pathways, rather than a single mechanism, are involved in the pathogenesis of ALS. However, most cellular models only explain single pathogenic mechanisms. The present study proposes the two main cytotoxic mechanisms: (1) veratridine (VTD), which induced Na+ and Ca2+ overload; and (2) the TARD DNA-binding protein 43 (TDP-43) in NSC-34 cell line as an in vitro model of ALS. The study was carried out by MTT as an indirect measurement of cell viability and by flow cytometry to determine cell death stages. The impact of Ca2+ overload combined with TDP-43 overexpression increased early apoptosis of NSC-34 cells. Furthermore, we found that ITH33/IQM9.21 (ITH33) exerted a neuroprotective effect in this model by reducing activation of the apoptotic pathway. Therefore, treatment with VTD in TDP-43 overexpressing NSC-34 cells is a good in vitro ALS model that makes it possible to test new neuroprotective compounds such as ITH33.
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Affiliation(s)
- Lamia Mouhid Al-Achbili
- Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Ana J Moreno-Ortega
- Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Servicio de Farmacología Clínica, Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Madrid, Universidad Autónoma de Madrid, Madrid, Spain
| | - Jorge Matías-Guiu
- Servicio de Neurología, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain; Instituto de Neurociencias, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - María F Cano-Abad
- Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Servicio de Farmacología Clínica, Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Madrid, Universidad Autónoma de Madrid, Madrid, Spain.
| | - Ana Ruiz-Nuño
- Instituto-Fundación Teófilo Hernando, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Servicio de Farmacología Clínica, Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Madrid, Universidad Autónoma de Madrid, Madrid, Spain.
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42
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Suzuki H, Matsuoka M. The Lysosomal Trafficking Transmembrane Protein 106B Is Linked to Cell Death. J Biol Chem 2016; 291:21448-21460. [PMID: 27563066 DOI: 10.1074/jbc.m116.737171] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Revised: 08/24/2016] [Indexed: 12/12/2022] Open
Abstract
A common genetic variation in the transmembrane protein 106B (TMEM106B) gene has been suggested to be a risk factor for frontotemporal lobar degeneration (FTLD) with inclusions of transactive response DNA-binding protein-43 (TDP-43) (FTLD-TDP), the most common pathological subtype in FTLD. Furthermore, previous studies have shown that TMEM106B levels are up-regulated in the brains of FTLD-TDP patients, although the significance of this finding remains unknown. In this study, we show that the overexpression of TMEM106B and its N-terminal fragments induces cell death, enhances oxidative stress-induced cytotoxicity, and causes the cleavage of TDP-43, which represents TDP-43 pathology, using cell-based models. TMEM106B-induced death is mediated by the caspase-dependent mitochondrial cell death pathways and possibly by the lysosomal cell death pathway. These findings suggest that the up-regulation of TMEM106B may increase the risk of FTLD by directly causing neurotoxicity and a pathological phenotype linked to FTLD-TDP.
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Affiliation(s)
| | - Masaaki Matsuoka
- From the Departments of Pharmacology and .,Dermatological Neuroscience, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo 160-8402, Japan
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43
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Ding X, Ma M, Teng J, Teng RKF, Zhou S, Yin J, Fonkem E, Huang JH, Wu E, Wang X. Exposure to ALS-FTD-CSF generates TDP-43 aggregates in glioblastoma cells through exosomes and TNTs-like structure. Oncotarget 2016; 6:24178-91. [PMID: 26172304 PMCID: PMC4695178 DOI: 10.18632/oncotarget.4680] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 06/12/2015] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) represent a continuum of devastating neurodegenerative diseases, characterized by transactive response DNA-binding protein of 43 kDa (TDP-43) aggregates accumulation throughout the nervous system. Despite rapidly emerging evidence suggesting the hypothesis of 'prion-like propagation' of TDP-43 positive inclusion in the regional spread of ALS symptoms, whether and how TDP-43 aggregates spread between cells is not clear. Herein, we established a cerebrospinal fluid (CSF)-cultured cell model to dissect mechanisms governing TDP-43 aggregates formation and propagation. Remarkably, intracellular TDP-43 mislocalization and aggregates were induced in the human glioma U251 cells following exposure to ALS-FTD-CSF but not ALS-CSF and normal control (NC) -CSF for 21 days. The exosomes derived from ALS-FTD-CSF were enriched in TDP-43 C-terminal fragments (CTFs). Incubation of ALS-FTD-CSF induced the increase of mislocated TDP-43 positive exosomes in U251 cells. We further demonstrated that exposure to ALS-FTD-CSF induced the generations of tunneling nanotubes (TNTs)-like structure and exosomes at different stages, which mediated the propagation of TDP-43 aggregates in the cultured U251 cells. Moreover, immunoblotting analyses revealed that abnormal activations of apoptosis and autophagy were induced in U251 cells, following incubation of ALS-CSF and ALS-FTD-CSF. Taken together, our data provide direct evidence that ALS-FTD-CSF has prion-like transmissible properties. TNTs-like structure and exosomes supply the routes for the transfer of TDP-43 aggregates, and selective inhibition of their over-generations may interrupt the progression of TDP-43 proteinopathy.
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Affiliation(s)
- Xuebing Ding
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Mingming Ma
- Department of Neurology, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China.,Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, USA
| | - Junfang Teng
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Robert K F Teng
- College of Engineering, California State University, Los Angeles, CA, USA
| | - Shuang Zhou
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, USA
| | - Jingzheng Yin
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Ekokobe Fonkem
- Scott & White Neuroscience Institute, Texas A & M Health Science Center, College of Medicine, Temple, TX, USA
| | - Jason H Huang
- Scott & White Neuroscience Institute, Texas A & M Health Science Center, College of Medicine, Temple, TX, USA
| | - Erxi Wu
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, USA
| | - Xuejing Wang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
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44
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Cascella R, Capitini C, Fani G, Dobson CM, Cecchi C, Chiti F. Quantification of the Relative Contributions of Loss-of-function and Gain-of-function Mechanisms in TAR DNA-binding Protein 43 (TDP-43) Proteinopathies. J Biol Chem 2016; 291:19437-48. [PMID: 27445339 DOI: 10.1074/jbc.m116.737726] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin positive inclusions (FTLD-U) are two clinically distinct neurodegenerative conditions sharing a similar histopathology characterized by the nuclear clearance of TDP-43 and its associated deposition into cytoplasmic inclusions in different areas of the central nervous system. Given the concomitant occurrence of TDP-43 nuclear depletion and cytoplasmic accumulation, it has been proposed that TDP-43 proteinopathies originate from either a loss-of-function (LOF) mechanism, a gain-of-function (GOF) process, or both. We have addressed this issue by transfecting murine NSC34 and N2a cells with siRNA for endogenous murine TDP-43 and with human recombinant TDP-43 inclusion bodies (IBs). These two strategies allowed the depletion of nuclear TDP-43 and the accumulation of cytoplasmic TDP-43 aggregates to occur separately and independently. Endogenous and exogenous TDP-43 were monitored and quantified using both immunofluorescence and Western blotting analysis, and nuclear functional TDP-43 was measured by monitoring the sortilin 1 mRNA splicing activity. Various degrees of TDP-43 cytoplasmic accumulation and nuclear TDP-43 depletion were achieved and the resulting cellular viability was evaluated, leading to a quantitative global analysis on the relative effects of LOF and GOF on the overall cytotoxicity. These were found to be ∼55% and 45%, respectively, in both cell lines and using both readouts of cell toxicity, showing that these two mechanisms are likely to contribute apparently equally to the pathologies of ALS and FTLD-U.
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Affiliation(s)
- Roberta Cascella
- From the Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, V.le GB Morgagni 50, 50134 Florence, Italy and
| | - Claudia Capitini
- From the Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, V.le GB Morgagni 50, 50134 Florence, Italy and
| | - Giulia Fani
- From the Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, V.le GB Morgagni 50, 50134 Florence, Italy and
| | - Christopher M Dobson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW United Kingdom
| | - Cristina Cecchi
- From the Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, V.le GB Morgagni 50, 50134 Florence, Italy and
| | - Fabrizio Chiti
- From the Section of Biochemistry, Department of Experimental and Clinical Biomedical Sciences, University of Florence, V.le GB Morgagni 50, 50134 Florence, Italy and
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45
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Mass spectrometric analysis of accumulated TDP-43 in amyotrophic lateral sclerosis brains. Sci Rep 2016; 6:23281. [PMID: 26980269 PMCID: PMC4793195 DOI: 10.1038/srep23281] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 03/03/2016] [Indexed: 12/12/2022] Open
Abstract
TDP-43 is the major disease-associated protein involved in the pathogenesis and progression of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin-positive inclusions linked to TDP-43 pathology (FTLD-TDP). Abnormal phosphorylation, truncation and cytoplasmic mis-localization are known to be the characteristics for the aggregated forms of TDP-43, and gain of toxic abnormal TDP-43 or loss of function of physiological TDP-43 have been suggested as the cause of neurodegeneration. However, most of the post-translational modifications or truncation sites in the abnormal TDP-43 in brains of patients remain to be identified by protein chemical analysis. In this study, we carried out a highly sensitive liquid chromatography-mass spectrometry analysis of Sarkosyl-insoluble pathological TDP-43 from brains of ALS patients and identified several novel phosphorylation sites, deamidation sites, and cleavage sites. Almost all modifications were localized in the Gly-rich C-terminal half. Most of the cleavage sites identified in this study are novel and are located in N-terminal half, suggesting that these sites may be more accessible to proteolytic enzymes. The data obtained in this study provide a foundation for the molecular mechanisms of TDP-43 aggregation and ALS pathogenesis.
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46
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Chiang CH, Grauffel C, Wu LS, Kuo PH, Doudeva LG, Lim C, Shen CKJ, Yuan HS. Structural analysis of disease-related TDP-43 D169G mutation: linking enhanced stability and caspase cleavage efficiency to protein accumulation. Sci Rep 2016; 6:21581. [PMID: 26883171 PMCID: PMC4756693 DOI: 10.1038/srep21581] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 01/25/2016] [Indexed: 12/12/2022] Open
Abstract
The RNA-binding protein TDP-43 forms intracellular inclusions in amyotrophic lateral sclerosis (ALS). While TDP-43 mutations have been identified in ALS patients, how these mutations are linked to ALS remains unclear. Here we examined the biophysical properties of six ALS-linked TDP-43 mutants and found that one of the mutants, D169G, had higher thermal stability than wild-type TDP-43 and that it was cleaved by caspase 3 more efficiently, producing increased levels of the C-terminal 35 kD fragments (TDP-35) in vitro and in neuroblastoma cells. The crystal structure of the TDP-43 RRM1 domain containing the D169G mutation in complex with DNA along with molecular dynamics simulations reveal that the D169G mutation induces a local conformational change in a β turn and increases the hydrophobic interactions in the RRM1 core, thus enhancing the thermal stability of the RRM1 domain. Our results provide the first crystal structure of TDP-43 containing a disease-linked D169G mutation and a disease-related mechanism showing that D169G mutant is more susceptible to proteolytic cleavage by caspase 3 into the pathogenic C-terminal 35-kD fragments due to its increased stability in the RRM1 domain. Modulation of TDP-43 stability and caspase cleavage efficiency could present an avenue for prevention and treatment of TDP-43-linked neurodegeneration.
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Affiliation(s)
- Chien-Hao Chiang
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan.,Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsin Chu, 30013, Taiwan
| | - Cédric Grauffel
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan
| | - Lien-Szu Wu
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Pan-Hsien Kuo
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
| | | | - Carmay Lim
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan
| | | | - Hanna S Yuan
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
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47
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Interaction of RNA with a C-terminal fragment of the amyotrophic lateral sclerosis-associated TDP43 reduces cytotoxicity. Sci Rep 2016; 6:19230. [PMID: 26757674 PMCID: PMC4725827 DOI: 10.1038/srep19230] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 12/01/2015] [Indexed: 12/12/2022] Open
Abstract
A hallmark of amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease, is formation of inclusion bodies (IBs) from misfolded proteins in neuronal cells. TAR RNA/DNA-binding protein 43 kDa (TDP43) is an ALS-causative protein forming IBs in ALS patients. The relation between localization of the IBs and neurotoxicity remains largely unknown. We characterized aggregation of fluorescently tagged TDP43 and its carboxyl-terminal fragments (CTFs) by analytical fluorescence imaging techniques. Quantitative time-lapse analysis in individual live cells showed that fluorescent-protein-tagged TDP43 was cleaved and a 35 kDa TDP43 CTF (TDP35) formed ubiquitin (Ub)-negative cytoplasmic IBs. Although TDP35 formed mildly toxic Ub-negative IBs in the cytoplasm, TDP25, another type of a TDP43 CTF, efficiently formed sufficiently toxic Ub-positive IBs. One- or two-color fluorescence correlation spectroscopy (FCS/FCCS) revealed that coaggregation of TDP25 with TDP43 was initiated by depletion of the RNA that binds to TDP25. Moreover, nuclear localization tagging TDP25 reduced the rate of neuronal cell death. These observations point to the need to elucidate the novel sequestration mechanism and details of the toxicity of the misfolded and aggregation-prone TDP43 CTFs (as well as the RNA binding and nuclear retention) in order to identify possible preventive interventions against ALS.
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Hu Y, Ge W, Wang X, Sutendra G, Zhao K, Dedeić Z, Slee EA, Baer C, Lu X. Caspase cleavage of iASPP potentiates its ability to inhibit p53 and NF-κB. Oncotarget 2015; 6:42478-90. [PMID: 26646590 PMCID: PMC4767446 DOI: 10.18632/oncotarget.6478] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 11/25/2015] [Indexed: 12/14/2022] Open
Abstract
An intriguing biological question relating to cell signaling is how the inflammatory mediator NF-kB and the tumour suppressor protein p53 can be induced by similar triggers, like DNA damage or infection, yet have seemingly opposing or sometimes cooperative biological functions. For example, the NF-κB subunit RelA/p65 has been shown to inhibit apoptosis, whereas p53 induces apoptosis. One potential explanation may be their co-regulation by common cellular factors: inhibitor of Apoptosis Stimulating p53 Protein (iASPP) is one such common regulator of both RelA/p65 and p53. Here we show that iASPP is a novel substrate of caspases in response to apoptotic stimuli. Caspase cleaves the N-terminal region of iASPP at SSLD294 resulting in a prominent 80kDa fragment of iASPP. This caspase cleavage site is conserved in various species from zebrafish to Homo sapiens. The 80kDa fragment of iASPP translocates from the cytoplasm to the nucleus via the RaDAR nuclear import pathway, independent of p53. The 80kDa iASPP fragment can bind and inhibit p53 or RelA/p65 more efficiently than full-length iASPP. Overall, these data reveal a potential novel regulation of p53 and RelA/p65 activities in response to apoptotic stimuli.
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Affiliation(s)
- Ying Hu
- The School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
- Ludwig Institute for Cancer Research Ltd., Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Wenjie Ge
- The School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Xingwen Wang
- The School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Gopinath Sutendra
- Ludwig Institute for Cancer Research Ltd., Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Kunming Zhao
- The School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Zinaida Dedeić
- Ludwig Institute for Cancer Research Ltd., Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Elizabeth A. Slee
- Ludwig Institute for Cancer Research Ltd., Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Caroline Baer
- Ludwig Institute for Cancer Research Ltd., Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Xin Lu
- Ludwig Institute for Cancer Research Ltd., Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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Shrestha A, Megeney LA. Yeast proteinopathy models: a robust tool for deciphering the basis of neurodegeneration. MICROBIAL CELL 2015; 2:458-465. [PMID: 28357271 PMCID: PMC5354604 DOI: 10.15698/mic2015.12.243] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein quality control or proteostasis is an essential determinant of basic cell health and aging. Eukaryotic cells have evolved a number of proteostatic mechanisms to ensure that proteins retain functional conformation, or are rapidly degraded when proteins misfold or self-aggregate. Disruption of proteostasis is now widely recognized as a key feature of aging related illness, specifically neurodegenerative disease. For example, Alzheimer’s disease, Huntington’s disease, Parkinson’s disease and Amyotrophic Lateral Sclerosis (ALS) each target and afflict distinct neuronal cell subtypes, yet this diverse array of human pathologies share the defining feature of aberrant protein aggregation within the affected cell population. Here, we review the use of budding yeast as a robust proxy to study the intersection between proteostasis and neurodegenerative disease. The humanized yeast model has proven to be an amenable platform to identify both, conserved proteostatic mechanisms across eukaryotic phyla and novel disease specific molecular dysfunction. Moreover, we discuss the intriguing concept that yeast specific proteins may be utilized as bona fide therapeutic agents, to correct proteostasis errors across various forms of neurodegeneration.
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Affiliation(s)
- Amit Shrestha
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Sprott Centre for Stem Cell Research, The Ottawa Hospital, Ottawa, Ontario, Canada. ; Department of Cellular and Molecular Medicine University of Ottawa, Ottawa, Ontario, Canada
| | - Lynn A Megeney
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Sprott Centre for Stem Cell Research, The Ottawa Hospital, Ottawa, Ontario, Canada. ; Department of Cellular and Molecular Medicine University of Ottawa, Ottawa, Ontario, Canada ; Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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