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Ikeda A, Meng H, Taniguchi D, Mio M, Funayama M, Nishioka K, Yoshida M, Li Y, Yoshino H, Inoshita T, Shiba-Fukushima K, Okubo Y, Sakurai T, Amo T, Aiba I, Saito Y, Saito Y, Murayama S, Atsuta N, Nakamura R, Tohnai G, Izumi Y, Morita M, Tamura A, Kano O, Oda M, Kuwabara S, Yamashita T, Sone J, Kaji R, Sobue G, Imai Y, Hattori N. CHCHD2 P14L, found in amyotrophic lateral sclerosis, exhibits cytoplasmic mislocalization and alters Ca 2+ homeostasis. PNAS NEXUS 2024; 3:pgae319. [PMID: 39131911 PMCID: PMC11316225 DOI: 10.1093/pnasnexus/pgae319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Accepted: 07/22/2024] [Indexed: 08/13/2024]
Abstract
CHCHD2 and CHCHD10, linked to Parkinson's disease and amyotrophic lateral sclerosis-frontotemporal dementia (ALS), respectively, are mitochondrial intermembrane proteins that form a heterodimer. This study aimed to investigate the impact of the CHCHD2 P14L variant, implicated in ALS, on mitochondrial function and its subsequent effects on cellular homeostasis. The missense variant of CHCHD2, P14L, found in a cohort of patients with ALS, mislocalized CHCHD2 to the cytoplasm, leaving CHCHD10 in the mitochondria. Drosophila lacking the CHCHD2 ortholog exhibited mitochondrial degeneration. In contrast, human CHCHD2 P14L, but not wild-type human CHCHD2, failed to suppress this degeneration, suggesting that P14L is a pathogenic variant. The mitochondrial Ca2+ buffering capacity was reduced in Drosophila neurons expressing human CHCHD2 P14L. The altered Ca2+-buffering phenotype was also observed in cultured human neuroblastoma SH-SY5Y cells expressing CHCHD2 P14L. In these cells, transient elevation of cytoplasmic Ca2+ facilitated the activation of calpain and caspase-3, accompanied by the processing and insolubilization of TDP-43. These observations suggest that CHCHD2 P14L causes abnormal Ca2+ dynamics and TDP-43 aggregation, reflecting the pathophysiology of ALS.
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Affiliation(s)
- Aya Ikeda
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Hongrui Meng
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Daisuke Taniguchi
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Muneyo Mio
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Manabu Funayama
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Center for Genomic and Regenerative Medicine, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Kenya Nishioka
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Mari Yoshida
- Department of Neuropathology, Institute for Medical Science of Aging, Aichi Medical University, Nagakute, Aichi 480-1195, Japan
| | - Yuanzhe Li
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Hiroyo Yoshino
- Research Institute for Diseases of Old Age, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Tsuyoshi Inoshita
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Kahori Shiba-Fukushima
- Department of Drug Development for Parkinson's Disease, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Yohei Okubo
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Takashi Sakurai
- Department of Cellular and Molecular Pharmacology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Taku Amo
- Department of Applied Chemistry, National Defense Academy, Yokosuka, Kanagawa 239-8686, Japan
| | - Ikuko Aiba
- Department of Neurology, NHO Higashinagoya National Hospital, Meito-ku, Nagoya, Aichi 465-8620, Japan
| | - Yufuko Saito
- Department of Neurology, NHO Higashinagoya National Hospital, Meito-ku, Nagoya, Aichi 465-8620, Japan
| | - Yuko Saito
- Brain Bank for Aging Research (Department of Neuropathology), Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo 173-0015, Japan
| | - Shigeo Murayama
- Brain Bank for Aging Research (Department of Neuropathology), Tokyo Metropolitan Institute for Geriatrics and Gerontology, Tokyo 173-0015, Japan
- Brain Bank for Neurodevelopmental, Neurological and Psychiatric Disorders, United Graduate School of Child Development, Osaka University, Osaka 565-0871, Japan
| | - Naoki Atsuta
- Department of Neurology, Aichi Medical University School of Medicine, Nagakute, Aichi 480-1195, Japan
| | - Ryoichi Nakamura
- Department of Neurology, Aichi Medical University School of Medicine, Nagakute, Aichi 480-1195, Japan
| | - Genki Tohnai
- Division of ALS Research, Aichi Medical University School of Medicine, Nagakute, Aichi 480-1195, Japan
| | - Yuishin Izumi
- Department of Neurology, Tokushima University Graduate School of Biomedical Sciences, Tokushima 770-8503, Japan
| | - Mitsuya Morita
- Division of Neurology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi 329-0498, Japan
| | - Asako Tamura
- Department of Neurology, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan
| | - Osamu Kano
- Department of Neurology, Toho University Faculty of Medicine, Ota-ku, Tokyo 143-8541, Japan
| | - Masaya Oda
- Department of Neurology, Vihara Hananosato Hospital, Miyoshi, Hiroshima 728-0001, Japan
| | - Satoshi Kuwabara
- Department of Neurology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba 260-8670, Japan
| | - Toru Yamashita
- Department of Neurology, Okayama University Graduate School of Medicine, Kita-ku, Okayama 700-8558, Japan
| | - Jun Sone
- Department of Neuropathology, Institute for Medical Science of Aging, Aichi Medical University, Nagakute, Aichi 480-1195, Japan
| | - Ryuji Kaji
- Department of Clinical Neuroscience, Tokushima University, Tokushima 770-8503, Japan
| | - Gen Sobue
- Aichi Medical University, Nagakute, Aichi 480-1195, Japan
| | - Yuzuru Imai
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Nobutaka Hattori
- Department of Neurology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Department of Research for Parkinson's Disease, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Department of Drug Development for Parkinson's Disease, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
- Neurodegenerative Disorders Collaborative Laboratory, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
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2
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Garcia-Vaquero ML, Heim M, Flix B, Pereira M, Palin L, Marques TM, Pinto FR, de Las Rivas J, Voigt A, Besse F, Gama-Carvalho M. Analysis of asymptomatic Drosophila models for ALS and SMA reveals convergent impact on functional protein complexes linked to neuro-muscular degeneration. BMC Genomics 2023; 24:576. [PMID: 37759179 PMCID: PMC10523761 DOI: 10.1186/s12864-023-09562-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 08/08/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND Spinal Muscular Atrophy (SMA) and Amyotrophic Lateral Sclerosis (ALS) share phenotypic and molecular commonalities, including the fact that they can be caused by mutations in ubiquitous proteins involved in RNA metabolism, namely SMN, TDP-43 and FUS. Although this suggests the existence of common disease mechanisms, there is currently no model to explain the resulting motor neuron dysfunction. In this work we generated a parallel set of Drosophila models for adult-onset RNAi and tagged neuronal expression of the fly orthologues of the three human proteins, named Smn, TBPH and Caz, respectively. We profiled nuclear and cytoplasmic bound mRNAs using a RIP-seq approach and characterized the transcriptome of the RNAi models by RNA-seq. To unravel the mechanisms underlying the common functional impact of these proteins on neuronal cells, we devised a computational approach based on the construction of a tissue-specific library of protein functional modules, selected by an overall impact score measuring the estimated extent of perturbation caused by each gene knockdown. RESULTS Transcriptome analysis revealed that the three proteins do not bind to the same RNA molecules and that only a limited set of functionally unrelated transcripts is commonly affected by their knock-down. However, through our integrative approach we were able to identify a concerted effect on protein functional modules, albeit acting through distinct targets. Most strikingly, functional annotation revealed that these modules are involved in critical cellular pathways for motor neurons, including neuromuscular junction function. Furthermore, selected modules were found to be significantly enriched in orthologues of human neuronal disease genes. CONCLUSIONS The results presented here show that SMA and ALS disease-associated genes linked to RNA metabolism functionally converge on neuronal protein complexes, providing a new hypothesis to explain the common motor neuron phenotype. The functional modules identified represent promising biomarkers and therapeutic targets, namely given their alteration in asymptomatic settings.
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Affiliation(s)
- Marina L Garcia-Vaquero
- BioISI - Institute for Biosystems and Integrative Sciences, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
- Department of Medicine and Cytometry General Service-15 Nucleus, Cancer Research Centre (IBMCC/CSIC/USAL/IBSAL), CIBERONC, 16 37007, Salamanca, Spain
| | - Marjorie Heim
- Institut de Biologie Valrose, Université Côte d'Azur, CNRS, 06108, Nice, Inserm, France
| | - Barbara Flix
- Department of Neurology, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany
| | - Marcelo Pereira
- BioISI - Institute for Biosystems and Integrative Sciences, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
| | - Lucile Palin
- Institut de Biologie Valrose, Université Côte d'Azur, CNRS, 06108, Nice, Inserm, France
| | - Tânia M Marques
- BioISI - Institute for Biosystems and Integrative Sciences, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
| | - Francisco R Pinto
- BioISI - Institute for Biosystems and Integrative Sciences, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
| | - Javier de Las Rivas
- Cancer Research Center (CiC-IBMCC, CSIC/USAL/IBSAL), Consejo Superior de Investigaciones Científicas (CSIC) and University of Salamanca (USAL), 37007, Salamanca, Spain
| | - Aaron Voigt
- Department of Neurology, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany
- JARA-BRAIN Institute Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbH RWTH Aachen University, 52074, Aachen, Germany
| | - Florence Besse
- Institut de Biologie Valrose, Université Côte d'Azur, CNRS, 06108, Nice, Inserm, France
| | - Margarida Gama-Carvalho
- BioISI - Institute for Biosystems and Integrative Sciences, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal.
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3
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Lo Piccolo L, Umegawachi T, Yeewa R, Potikanond S, Nimlamool W, Prachayasittikul V, Gotoh Y, Yoshida H, Yamaguchi M, Jantrapirom S. A Novel Drosophila-based Drug Repurposing Platform Identified Fingolimod As a Potential Therapeutic for TDP-43 Proteinopathy. Neurotherapeutics 2023; 20:1330-1346. [PMID: 37493896 PMCID: PMC10480388 DOI: 10.1007/s13311-023-01406-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2023] [Indexed: 07/27/2023] Open
Abstract
Pathogenic changes to TAR DNA-binding protein 43 (TDP-43) leading to alteration of its homeostasis are a common feature shared by several progressive neurodegenerative diseases for which there is no effective therapy. Here, we developed Drosophila lines expressing either wild type TDP-43 (WT) or that carrying an Amyotrophic Lateral Sclerosis /Frontotemporal Lobar Degeneration-associating G384C mutation that recapitulate several aspects of the TDP-43 pathology. To identify potential therapeutics for TDP-43-related diseases, we implemented a drug repurposing strategy that involved three consecutive steps. Firstly, we evaluated the improvement of eclosion rate, followed by the assessment of locomotive functions at early and late developmental stages. Through this approach, we successfully identified fingolimod, as a promising candidate for modulating TDP-43 toxicity. Fingolimod exhibited several beneficial effects in both WT and mutant models of TDP-43 pathology, including post-transcriptional reduction of TDP-43 levels, rescue of pupal lethality, and improvement of locomotor dysfunctions. These findings provide compelling evidence for the therapeutic potential of fingolimod in addressing TDP-43 pathology, thereby strengthening the rationale for further investigation and consideration of clinical trials. Furthermore, our study demonstrates the utility of our Drosophila-based screening pipeline in identifying novel therapeutics for TDP-43-related diseases. These findings encourage further scale-up screening endeavors using this platform to discover additional compounds with therapeutic potential for TDP-43 pathology.
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Affiliation(s)
- Luca Lo Piccolo
- Center of Multidisciplinary Technology for Advanced Medicine (CMUTEAM), Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Faculty of Medicine, Musculoskeletal Science and Translational Research Centre (MSTR), Chiang Mai University, Chiang Mai, Thailand
| | | | - Ranchana Yeewa
- Center of Multidisciplinary Technology for Advanced Medicine (CMUTEAM), Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Saranyapin Potikanond
- Department of Pharmacology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Wutigri Nimlamool
- Department of Pharmacology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Virapong Prachayasittikul
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Chiang Mai, Thailand
| | - Yusuke Gotoh
- Platform Technology Research Unit, Sumitomo Pharma Co., Ltd, Kyoto, Japan
| | - Hideki Yoshida
- Department of Applied Biology, Kyoto Institute of Technology, Kyoto, Japan
| | | | - Salinee Jantrapirom
- Department of Pharmacology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
- Drosophila Centre for Human Diseases and Drug Discovery (DHD), Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
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4
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De Marchi F, Franjkic T, Schito P, Russo T, Nimac J, Chami AA, Mele A, Vidatic L, Kriz J, Julien JP, Apic G, Russell RB, Rogelj B, Cannon JR, Baralle M, Agosta F, Hecimovic S, Mazzini L, Buratti E, Munitic I. Emerging Trends in the Field of Inflammation and Proteinopathy in ALS/FTD Spectrum Disorder. Biomedicines 2023; 11:1599. [PMID: 37371694 PMCID: PMC10295684 DOI: 10.3390/biomedicines11061599] [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: 04/28/2023] [Revised: 05/27/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Proteinopathy and neuroinflammation are two main hallmarks of neurodegenerative diseases. They also represent rare common events in an exceptionally broad landscape of genetic, environmental, neuropathologic, and clinical heterogeneity present in patients. Here, we aim to recount the emerging trends in amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD) spectrum disorder. Our review will predominantly focus on neuroinflammation and systemic immune imbalance in ALS and FTD, which have recently been highlighted as novel therapeutic targets. A common mechanism of most ALS and ~50% of FTD patients is dysregulation of TAR DNA-binding protein 43 (TDP-43), an RNA/DNA-binding protein, which becomes depleted from the nucleus and forms cytoplasmic aggregates in neurons and glia. This, in turn, via both gain and loss of function events, alters a variety of TDP-43-mediated cellular events. Experimental attempts to target TDP-43 aggregates or manipulate crosstalk in the context of inflammation will be discussed. Targeting inflammation, and the immune system in general, is of particular interest because of the high plasticity of immune cells compared to neurons.
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Affiliation(s)
- Fabiola De Marchi
- Department of Neurology and ALS Centre, University of Piemonte Orientale, Maggiore Della Carità Hospital, Corso Mazzini 18, 28100 Novara, Italy; (F.D.M.); (A.M.)
| | - Toni Franjkic
- Laboratory for Molecular Immunology, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia;
- Metisox, Cambridge CB24 9NL, UK;
| | - Paride Schito
- Department of Neurology & Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy; (P.S.); (T.R.)
| | - Tommaso Russo
- Department of Neurology & Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy; (P.S.); (T.R.)
| | - Jerneja Nimac
- Department of Biotechnology, Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia; (J.N.); (B.R.)
- Graduate School of Biomedicine, Faculty of Medicine, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Anna A. Chami
- CERVO Research Centre, Laval University, Quebec City, QC G1J 2G3, Canada; (A.A.C.); (J.K.); (J.-P.J.)
| | - Angelica Mele
- Department of Neurology and ALS Centre, University of Piemonte Orientale, Maggiore Della Carità Hospital, Corso Mazzini 18, 28100 Novara, Italy; (F.D.M.); (A.M.)
| | - Lea Vidatic
- Laboratory for Neurodegenerative Disease Research, Division of Molecular Medicine, Ruder Boskovic Institute, 10000 Zagreb, Croatia; (L.V.); (S.H.)
| | - Jasna Kriz
- CERVO Research Centre, Laval University, Quebec City, QC G1J 2G3, Canada; (A.A.C.); (J.K.); (J.-P.J.)
| | - Jean-Pierre Julien
- CERVO Research Centre, Laval University, Quebec City, QC G1J 2G3, Canada; (A.A.C.); (J.K.); (J.-P.J.)
| | | | | | - Boris Rogelj
- Department of Biotechnology, Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia; (J.N.); (B.R.)
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Jason R. Cannon
- School of Health Sciences, Purdue University, West Lafayette, IN 47907, USA;
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | | | - Federica Agosta
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy;
| | - Silva Hecimovic
- Laboratory for Neurodegenerative Disease Research, Division of Molecular Medicine, Ruder Boskovic Institute, 10000 Zagreb, Croatia; (L.V.); (S.H.)
| | - Letizia Mazzini
- Department of Neurology and ALS Centre, University of Piemonte Orientale, Maggiore Della Carità Hospital, Corso Mazzini 18, 28100 Novara, Italy; (F.D.M.); (A.M.)
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34149 Trieste, Italy
| | - Ivana Munitic
- Laboratory for Molecular Immunology, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia;
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Diaz-Garcia S, Ko VI, Vazquez-Sanchez S, Chia R, Arogundade OA, Rodriguez MJ, Traynor BJ, Cleveland D, Ravits J. Nuclear depletion of RNA-binding protein ELAVL3 (HuC) in sporadic and familial amyotrophic lateral sclerosis. Acta Neuropathol 2021; 142:985-1001. [PMID: 34618203 PMCID: PMC8568872 DOI: 10.1007/s00401-021-02374-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 11/07/2022]
Abstract
Amyotrophic lateral sclerosis is a progressive fatal neurodegenerative disease caused by loss of motor neurons and characterized neuropathologically in almost all cases by nuclear depletion and cytoplasmic aggregation of TDP-43, a nuclear RNA-binding protein (RBP). We identified ELAVL3 as one of the most downregulated genes in our transcriptome profiles of laser captured microdissection of motor neurons from sporadic ALS nervous systems and the most dysregulated of all RBPs. Neuropathological characterizations showed ELAVL3 nuclear depletion in a great percentage of remnant motor neurons, sometimes accompanied by cytoplasmic accumulations. These abnormalities were common in sporadic cases with and without intermediate expansions in ATXN2 and familial cases carrying mutations in C9orf72 and SOD1. Depletion of ELAVL3 occurred at both the RNA and protein levels and a short protein isoform was identified, but it is not related to a TDP-43-dependent cryptic exon in intron 3. Strikingly, ELAVL3 abnormalities were more frequent than TDP-43 abnormalities and occurred in motor neurons still with normal nuclear TDP-43 present, but all neurons with abnormal TDP-43 also had abnormal ELAVL3. In a neuron-like cell culture model using SH-SY5Y cells, ELAVL3 mislocalization occurred weeks before TDP-43 abnormalities were seen. We interrogated genetic databases, but did not identify association of ELAVL3 genetic structure with ALS. Taken together, these findings suggest that ELAVL3 is an important RBP in ALS pathogenesis acquired early and the neuropathological data suggest that it is involved by loss of function rather than cytoplasmic toxicity.
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Affiliation(s)
- Sandra Diaz-Garcia
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093-0670 USA
| | - Vivian I. Ko
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093-0670 USA
| | - Sonia Vazquez-Sanchez
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0670 USA
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA USA
| | - Ruth Chia
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892-3707 USA
| | | | - Maria J. Rodriguez
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093-0670 USA
| | - Bryan J. Traynor
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892-3707 USA
| | - Don Cleveland
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0670 USA
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA USA
| | - John Ravits
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093-0670 USA
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6
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Cragnaz L, Spinelli G, De Conti L, Bureau EA, Brownlees J, Feiguin F, Romano V, Skoko N, Klima R, Kettleborough CA, Baralle FE, Baralle M. Thioridazine reverts the phenotype in cellular and Drosophila models of amyotrophic lateral sclerosis by enhancing TDP-43 aggregate clearance. Neurobiol Dis 2021; 160:105515. [PMID: 34571136 DOI: 10.1016/j.nbd.2021.105515] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 08/06/2021] [Accepted: 09/21/2021] [Indexed: 01/22/2023] Open
Abstract
Brain inclusions mainly composed of misfolded and aggregated TAR DNA binding protein 43 (TDP-43), are characteristic hallmarks of amyotrophic lateral sclerosis (ALS). Irrespective of the role played by the inclusions, their reduction represents an important therapeutic pathway that is worth exploring. Their removal can either lead to the recovery of TDP-43 function by removing the self-templating conformers that sequester the protein in the inclusions, and/or eliminate any potential intrinsic toxicity of the aggregates. The search for curative therapies has been hampered by the lack of ALS models for use in high-throughput screening. We adapted, optimised, and extensively characterised our previous ALS cellular model for such use. The model demonstrated efficient aggregation of endogenous TDP-43, and concomitant loss of its splicing regulation function. We provided a proof-of-principle for its eventual use in high-throughput screening using compounds of the tricyclic family and showed that recovery of TDP-43 function can be achieved by the enhanced removal of TDP-43 aggregates by these compounds. We observed that the degradation of the aggregates occurs independent of the autophagy pathway beyond autophagosome-lysosome fusion, but requires a functional proteasome pathway. The in vivo translational effect of the cellular model was tested with two of these compounds in a Drosophila model expressing a construct analogous to the cellular model, where thioridazine significantly improved the locomotive defect. Our findings have important implications as thioridazine cleared TDP-43 aggregates and recovered TDP-43 functionality. This study also highlights the importance of a two-stage, in vitro and in vivo model system to cross-check the search for small molecules that can clear TDP-43 aggregates in TDP-43 proteinopathies.
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Affiliation(s)
- Lucia Cragnaz
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34149 Trieste, Italy
| | - Greta Spinelli
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34149 Trieste, Italy
| | - Laura De Conti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34149 Trieste, Italy
| | - Emilie A Bureau
- LifeArc, Accelerator Building, Open Innovation Campus, Stevenage SG1 2FX, United Kingdom
| | - Janet Brownlees
- LifeArc, Accelerator Building, Open Innovation Campus, Stevenage SG1 2FX, United Kingdom
| | - Fabian Feiguin
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34149 Trieste, Italy; Department of Life and Environmental Sciences, University of Cagliari, 09042 Monserrato, Cagliari, Italy
| | - Valentina Romano
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34149 Trieste, Italy
| | - Natasa Skoko
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34149 Trieste, Italy
| | - Raffaella Klima
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34149 Trieste, Italy
| | | | - Francisco E Baralle
- Fondazione Italiana Fegato-Onlus, Bldg. Q, AREA Science Park, ss14, Km 163.5, Basovizza, 34149 Trieste, Italy
| | - Marco Baralle
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34149 Trieste, Italy.
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7
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Rajič Bumber J, Pilipović K, Janković T, Dolenec P, Gržeta N, Križ J, Župan G. Repetitive Traumatic Brain Injury Is Associated With TDP-43 Alterations, Neurodegeneration, and Glial Activation in Mice. J Neuropathol Exp Neurol 2021; 80:2-14. [PMID: 33212475 DOI: 10.1093/jnen/nlaa130] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Increasing evidence points to a relationship between repetitive mild traumatic brain injury (mTBI), the Tar DNA binding protein 43 (TDP-43) pathology and some neurodegenerative diseases, but the underlying pathophysiological mechanisms are still unknown. We examined TDP-43 regulation, neurodegeneration, and glial responses following repetitive mTBI in nontransgenic mice and in animals with overexpression of human mutant TDP-43 protein (TDP-43G348C). In the frontal cortices of the injured nontransgenic animals, early TDP-43 cytoplasmatic translocation and overexpression of the protein and its pathological forms were detected. In the injured animals of both genotypes, neurodegeneration and pronounced glial activity were detected in the optic tract. In TDP-43G348C mice, these changes were significantly higher at day 7 after the last mTBI compared with the values in the nontransgenic animals. Results of this study suggest that the changes in the TDP-43 regulation in the frontal cortices of the nontransgenic animals were a transient stress response to the brain injury. Repetitive mTBI did not produce additional TDP-43 dysregulation or neurodegeneration or pronounced gliosis in the frontal cortex of TDP-43G348C mice. Our research also suggests that overexpression of mutated human TDP-43 possibly predisposes the brain to more intense neurodegeneration and glial activation in the optic tract after repetitive mTBI.
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Affiliation(s)
- Jelena Rajič Bumber
- From the Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Kristina Pilipović
- From the Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Tamara Janković
- From the Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Petra Dolenec
- From the Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Nika Gržeta
- From the Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Jasna Križ
- Department of Psychiatry and Neuroscience, Faculty of Medicine, University of Laval, Quebec, QC, Canada
| | - Gordana Župan
- From the Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
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8
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Layalle S, They L, Ourghani S, Raoul C, Soustelle L. Amyotrophic Lateral Sclerosis Genes in Drosophila melanogaster. Int J Mol Sci 2021; 22:ijms22020904. [PMID: 33477509 PMCID: PMC7831090 DOI: 10.3390/ijms22020904] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating adult-onset neurodegenerative disease characterized by the progressive degeneration of upper and lower motoneurons. Most ALS cases are sporadic but approximately 10% of ALS cases are due to inherited mutations in identified genes. ALS-causing mutations were identified in over 30 genes with superoxide dismutase-1 (SOD1), chromosome 9 open reading frame 72 (C9orf72), fused in sarcoma (FUS), and TAR DNA-binding protein (TARDBP, encoding TDP-43) being the most frequent. In the last few decades, Drosophila melanogaster emerged as a versatile model for studying neurodegenerative diseases, including ALS. In this review, we describe the different Drosophila ALS models that have been successfully used to decipher the cellular and molecular pathways associated with SOD1, C9orf72, FUS, and TDP-43. The study of the known fruit fly orthologs of these ALS-related genes yielded significant insights into cellular mechanisms and physiological functions. Moreover, genetic screening in tissue-specific gain-of-function mutants that mimic ALS-associated phenotypes identified disease-modifying genes. Here, we propose a comprehensive review on the Drosophila research focused on four ALS-linked genes that has revealed novel pathogenic mechanisms and identified potential therapeutic targets for future therapy.
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Affiliation(s)
- Sophie Layalle
- The Neuroscience Institute of Montpellier, INSERM, University of Montpellier, 34091 Montpellier, France; (S.L.); (L.T.); (S.O.)
| | - Laetitia They
- The Neuroscience Institute of Montpellier, INSERM, University of Montpellier, 34091 Montpellier, France; (S.L.); (L.T.); (S.O.)
| | - Sarah Ourghani
- The Neuroscience Institute of Montpellier, INSERM, University of Montpellier, 34091 Montpellier, France; (S.L.); (L.T.); (S.O.)
| | - Cédric Raoul
- The Neuroscience Institute of Montpellier, INSERM, University of Montpellier, 34091 Montpellier, France; (S.L.); (L.T.); (S.O.)
- Laboratory of Neurobiology, Kazan Federal University, 420008 Kazan, Russia
- Correspondence: (C.R.); (L.S.)
| | - Laurent Soustelle
- The Neuroscience Institute of Montpellier, INSERM, University of Montpellier, 34091 Montpellier, France; (S.L.); (L.T.); (S.O.)
- Correspondence: (C.R.); (L.S.)
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9
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Buratti E. Trends in Understanding the Pathological Roles of TDP-43 and FUS Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1281:243-267. [PMID: 33433879 DOI: 10.1007/978-3-030-51140-1_15] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Following the discovery of TDP-43 and FUS involvement in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar dementia (FTLD), the major challenge in the field has been to understand their physiological functions, both in normal and disease conditions. The hope is that this knowledge will improve our understanding of disease and lead to the development of effective therapeutic options. Initially, the focus has been directed at characterizing the role of these proteins in the control of RNA metabolism, because the main function of TDP-43 and FUS is to bind coding and noncoding RNAs to regulate their life cycle within cells. As a result, we now have an in-depth picture of the alterations that occur in RNA metabolism following their aggregation in various ALS/FTLD models and, to a somewhat lesser extent, in patients' brains. In parallel, progress has been made with regard to understanding how aggregation of these proteins occurs in neurons, how it can spread in different brain regions, and how these changes affect various metabolic cellular pathways to result in neuronal death. The aim of this chapter will be to provide a general overview of the trending topics in TDP-43 and FUS investigations and to highlight what might represent the most promising avenues of research in the years to come.
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Affiliation(s)
- Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.
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10
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McAlary L, Chew YL, Lum JS, Geraghty NJ, Yerbury JJ, Cashman NR. Amyotrophic Lateral Sclerosis: Proteins, Proteostasis, Prions, and Promises. Front Cell Neurosci 2020; 14:581907. [PMID: 33328890 PMCID: PMC7671971 DOI: 10.3389/fncel.2020.581907] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is characterized by the progressive degeneration of the motor neurons that innervate muscle, resulting in gradual paralysis and culminating in the inability to breathe or swallow. This neuronal degeneration occurs in a spatiotemporal manner from a point of onset in the central nervous system (CNS), suggesting that there is a molecule that spreads from cell-to-cell. There is strong evidence that the onset and progression of ALS pathology is a consequence of protein misfolding and aggregation. In line with this, a hallmark pathology of ALS is protein deposition and inclusion formation within motor neurons and surrounding glia of the proteins TAR DNA-binding protein 43, superoxide dismutase-1, or fused in sarcoma. Collectively, the observed protein aggregation, in conjunction with the spatiotemporal spread of symptoms, strongly suggests a prion-like propagation of protein aggregation occurs in ALS. In this review, we discuss the role of protein aggregation in ALS concerning protein homeostasis (proteostasis) mechanisms and prion-like propagation. Furthermore, we examine the experimental models used to investigate these processes, including in vitro assays, cultured cells, invertebrate models, and murine models. Finally, we evaluate the therapeutics that may best prevent the onset or spread of pathology in ALS and discuss what lies on the horizon for treating this currently incurable disease.
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Affiliation(s)
- Luke McAlary
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Yee Lian Chew
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Jeremy Stephen Lum
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Nicholas John Geraghty
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Justin John Yerbury
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Neil R. Cashman
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
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11
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Otte CG, Fortuna TR, Mann JR, Gleixner AM, Ramesh N, Pyles NJ, Pandey UB, Donnelly CJ. Optogenetic TDP-43 nucleation induces persistent insoluble species and progressive motor dysfunction in vivo. Neurobiol Dis 2020; 146:105078. [PMID: 32927062 DOI: 10.1016/j.nbd.2020.105078] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 07/22/2020] [Accepted: 09/05/2020] [Indexed: 12/11/2022] Open
Abstract
TDP-43 is a predominantly nuclear DNA/RNA binding protein that is often mislocalized into insoluble cytoplasmic inclusions in post-mortem patient tissue in a variety of neurodegenerative disorders including Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal dementia (FTD). The underlying causes of TDP-43 proteinopathies remain unclear, but recent studies indicate the formation of these protein assemblies is driven by aberrant phase transitions of RNA deficient TDP-43. Technical limitations have prevented our ability to understand how TDP-43 proteinopathy relates to disease pathogenesis. Current animal models of TDP-43 proteinopathy often rely on overexpression of wild-type TDP-43 to non-physiological levels that may initiate neurotoxicity through nuclear gain of function mechanisms, or by the expression of disease-causing mutations found in only a fraction of ALS patients. New technologies allowing for light-responsive control of subcellular protein crowding provide a promising approach to drive intracellular protein aggregation, as we have previously demonstrated in vitro. Here we present a model for the optogenetic induction of TDP-43 proteinopathy in Drosophila that recapitulates key features of patient pathology, including detergent insoluble cytoplamsic inclusions and progressive motor dysfunction.
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Affiliation(s)
- Charlton G Otte
- Physician Scientist Training Program, University of Pittsburgh School of Medicine, United States of America; Department of Neurobiology, University of Pittsburgh School of Medicine, United States of America; LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, United States of America
| | - Tyler R Fortuna
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, United States of America
| | - Jacob R Mann
- Center for Neuroscience, University of Pittsburgh, United States of America; Department of Neurobiology, University of Pittsburgh School of Medicine, United States of America; Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, United States of America; Center for Protein Conformational Diseases, University of Pittsburgh, United States of America; LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, United States of America
| | - Amanda M Gleixner
- Department of Neurobiology, University of Pittsburgh School of Medicine, United States of America; Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, United States of America; Center for Protein Conformational Diseases, University of Pittsburgh, United States of America; LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, United States of America
| | - Nandini Ramesh
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, United States of America
| | - Noah J Pyles
- Physician Scientist Training Program, University of Pittsburgh School of Medicine, United States of America; Department of Neurobiology, University of Pittsburgh School of Medicine, United States of America; LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, United States of America
| | - Udai B Pandey
- Center for Neuroscience, University of Pittsburgh, United States of America; Center for Protein Conformational Diseases, University of Pittsburgh, United States of America; Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, United States of America
| | - Christopher J Donnelly
- Physician Scientist Training Program, University of Pittsburgh School of Medicine, United States of America; Center for Neuroscience, University of Pittsburgh, United States of America; Department of Neurobiology, University of Pittsburgh School of Medicine, United States of America; Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, United States of America; Center for Protein Conformational Diseases, University of Pittsburgh, United States of America; LiveLikeLou Center for ALS Research, University of Pittsburgh Brain Institute, United States of America.
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12
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Zhang K, Coyne AN, Lloyd TE. Drosophila models of amyotrophic lateral sclerosis with defects in RNA metabolism. Brain Res 2018; 1693:109-120. [PMID: 29752901 DOI: 10.1016/j.brainres.2018.04.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 04/27/2018] [Accepted: 04/28/2018] [Indexed: 12/12/2022]
Abstract
The fruit fly Drosophila Melanogaster has been widely used to study neurodegenerative diseases. The conservation of nervous system biology coupled with the rapid life cycle and powerful genetic tools in the fly have enabled the identification of novel therapeutic targets that have been validated in vertebrate model systems and human patients. A recent example is in the study of the devastating motor neuron degenerative disease amyotrophic lateral sclerosis (ALS). Mutations in genes that regulate RNA metabolism are a major cause of inherited ALS, and functional analysis of these genes in the fly nervous system has shed light on how mutations cause disease. Importantly, unbiased genetic screens have identified key pathways that contribute to ALS pathogenesis such as nucleocytoplasmic transport and stress granule assembly. In this review, we will discuss the utilization of Drosophila models of ALS with defects in RNA metabolism.
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Affiliation(s)
- Ke Zhang
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Alyssa N Coyne
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Thomas E Lloyd
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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13
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Langellotti S, Romano G, Feiguin F, Baralle FE, Romano M. RhoGAPp190: A potential player in tbph-mediated neurodegeneration in Drosophila. PLoS One 2018; 13:e0195845. [PMID: 29652933 PMCID: PMC5898758 DOI: 10.1371/journal.pone.0195845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 04/01/2018] [Indexed: 12/13/2022] Open
Abstract
TDP-43 is an ubiquitous and highly conserved ribonucleoprotein involved in several cellular processes including pre-mRNA splicing, transcription, mRNA stability and transport. Notwithstanding the evidence of TDP-43 involvement in the pathogenesis of different neurodegenerative disorders (i.e. ALS and FTLD), the underlying mechanisms are still unclear. Given the high degree of functional similarity between the human and fly orthologs of TDP-43, Drosophila melanogaster is a simple and useful model to study the pathophysiological role of this protein in vivo. It has been demonstrated that the depletion of the TDP-43 fly ortholog (tbph) induces deficient locomotive behaviors and reduces life span and anatomical defects at the neuromuscular junction. In this study, using the known binding specificity of TDP-43/tbph for (UG) repeated sequences, we performed a bioinformatic screening for fly genes with at least 6 (TG) repeats in a row within the 3'-UTR regions in order to identify the genes that might be regulated by this factor. Among these genes, we were able to identify RhoGAPp190 as a potential target of the tbph-mediated neurodegeneration. RhoGAPp190 is a negative regulator of Drosophila RhoA, a GTPase protein implicated in the fine modulation of critical cellular processes including axon branch stability and motor axon defasciculation at muscle level and cognitive processes. We were able to demonstrate that the RhoGAPp190 expression is upregulated in a tbph-null fly model, providing evidence that this deregulation is associated to tbph silencing. Our results introduce RhoGAPp190 as a novel potential mediator in the complex scenario of events resulting from in vivo tbph loss-of-function.
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Affiliation(s)
- Simona Langellotti
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Giulia Romano
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Fabian Feiguin
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | - Maurizio Romano
- Department of Life Sciences, University of Trieste, Trieste, Italy
- * E-mail:
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14
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Appocher C, Mohagheghi F, Cappelli S, Stuani C, Romano M, Feiguin F, Buratti E. Major hnRNP proteins act as general TDP-43 functional modifiers both in Drosophila and human neuronal cells. Nucleic Acids Res 2017; 45:8026-8045. [PMID: 28575377 PMCID: PMC5570092 DOI: 10.1093/nar/gkx477] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 05/16/2017] [Indexed: 12/13/2022] Open
Abstract
Nuclear factor TDP-43 is known to play an important role in several neurodegenerative pathologies. In general, TDP-43 is an abundant protein within the eukaryotic nucleus that binds to many coding and non-coding RNAs and influence their processing. Using Drosophila, we have performed a functional screening to establish the ability of major hnRNP proteins to affect TDP-43 overexpression/depletion phenotypes. Interestingly, we observed that lowering hnRNP and TDP-43 expression has a generally harmful effect on flies locomotor abilities. In parallel, our study has also identified a distinct set of hnRNPs that is capable of powerfully rescuing TDP-43 toxicity in the fly eye (Hrb27c, CG42458, Glo and Syp). Most importantly, removing the human orthologs of Hrb27c (DAZAP1) in human neuronal cell lines can correct several pre-mRNA splicing events altered by TDP-43 depletion. Moreover, using RNA sequencing analysis we show that DAZAP1 and TDP-43 can co-regulate an extensive number of biological processes and molecular functions potentially important for the neuron/motor neuron pathophysiology. Our results suggest that changes in hnRNP expression levels can significantly modulate TDP-43 functions and affect pathological outcomes.
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Affiliation(s)
- Chiara Appocher
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34149 Trieste, Italy
| | - Fatemeh Mohagheghi
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34149 Trieste, Italy
| | - Sara Cappelli
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34149 Trieste, Italy
| | - Cristiana Stuani
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34149 Trieste, Italy
| | - Maurizio Romano
- Department of Life Sciences, University of Trieste, Via A. Valerio 28, 34127 Trieste, Italy
| | - Fabian Feiguin
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34149 Trieste, Italy
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34149 Trieste, Italy
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15
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Byrne DJ, Harmon MJ, Simpson JC, Blackstone C, O'Sullivan NC. Roles for the VCP co-factors Npl4 and Ufd1 in neuronal function in Drosophila melanogaster. J Genet Genomics 2017; 44:493-501. [PMID: 29037990 PMCID: PMC5666124 DOI: 10.1016/j.jgg.2017.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 06/02/2017] [Accepted: 06/19/2017] [Indexed: 12/18/2022]
Abstract
The VCP-Ufd1-Npl4 complex regulates proteasomal processing within cells by delivering ubiquitinated proteins to the proteasome for degradation. Mutations in VCP are associated with two neurodegenerative diseases, amyotrophic lateral sclerosis (ALS) and inclusion body myopathy with Paget's disease of the bone and frontotemporal dementia (IBMPFD), and extensive study has revealed crucial functions of VCP within neurons. By contrast, little is known about the functions of Npl4 or Ufd1 in vivo. Using neuronal-specific knockdown of Npl4 or Ufd1 in Drosophila melanogaster, we infer that Npl4 contributes to microtubule organization within developing motor neurons. Moreover, Npl4 RNAi flies present with neurodegenerative phenotypes including progressive locomotor deficits, reduced lifespan and increased accumulation of TAR DNA-binding protein-43 homolog (TBPH). Knockdown, but not overexpression, of TBPH also exacerbates Npl4 RNAi-associated adult-onset neurodegenerative phenotypes. In contrast, we find that neuronal knockdown of Ufd1 has little effect on neuromuscular junction (NMJ) organization, TBPH accumulation or adult behaviour. These findings suggest the differing neuronal functions of Npl4 and Ufd1 in vivo.
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Affiliation(s)
- Dwayne J Byrne
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Mark J Harmon
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Jeremy C Simpson
- UCD School of Biology and Environmental Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Craig Blackstone
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin 4, Ireland.
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16
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Osuru HP, Pramoonjago P, Abhyankar MM, Swanson E, Roker LA, Cathro H, Reddi PP. Immunolocalization of TAR DNA-binding protein of 43 kDa (TDP-43) in mouse seminiferous epithelium. Mol Reprod Dev 2017; 84:675-685. [PMID: 28600885 DOI: 10.1002/mrd.22851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 12/13/2022]
Abstract
TAR DNA-binding protein of 43 kDa (TDP-43) is an evolutionarily conserved, ubiquitously expressed, multi-functional DNA/RNA-binding protein with roles in gene transcription, mRNA splicing, stability, transport, micro RNA biogenesis, and suppression of transposons. Aberrant expression of TDP-43 in testis and sperm was recently shown to be associated with male infertility, which highlights the need to understand better the expression of TDP-43 in the testis. We previously cloned TDP-43 from a mouse testis cDNA library, and showed that it functions as a transcriptional repressor and regulates the precise spatiotemporal expression of the Acrv1 gene, which encodes the acrosomal protein SP-10, during spermatogenesis. Here, we performed immunoblotting and immunohistochemistry of the mouse testis using four separate antibodies recognizing the amino and carboxyl termini of TDP-43. TDP-43 is present in the nuclei of germ cells as well as Sertoli cells. TDP-43 expression begins in type B/intermediate spermatogonia, peaks in preleptotene spermatocytes, and becomes undetectable in leptotene and zygotene spermatocytes. Pachytene spermatocytes and early round spermatids again express TDP-43, but its abundance diminishes later in spermatids (at steps 5-8). Interestingly, two of the four antibodies showed TDP-43 expression in spermatids at steps 9-10, which coincides with the initial phase of the histone-to-protamine transition. Immunoreactivity patterns observed in the study suggest that TDP-43 assumes different conformational states at different stages of spermatogenesis. TDP-43 pathology has been extensively studied in the context of neurodegenerative diseases; its role in spermatogenesis warrants further detailed investigation of the involvement of TDP-43 in male infertility.
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Affiliation(s)
- Hari Prasad Osuru
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Patcharin Pramoonjago
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Mayuresh M Abhyankar
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Eric Swanson
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - LaToya Ann Roker
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Helen Cathro
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Prabhakara P Reddi
- Department of Comparative Biosciences, University of Illinois at Urbana Champaign, Urbana, Illinois
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17
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Liu YJ, Tsai PY, Chern Y. Energy Homeostasis and Abnormal RNA Metabolism in Amyotrophic Lateral Sclerosis. Front Cell Neurosci 2017; 11:126. [PMID: 28522961 PMCID: PMC5415567 DOI: 10.3389/fncel.2017.00126] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 04/18/2017] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease that is clinically characterized by progressive muscle weakness and impaired voluntary movement due to the loss of motor neurons in the brain, brain stem and spinal cord. To date, no effective treatment is available. Ample evidence suggests that impaired RNA homeostasis and abnormal energy status are two major pathogenesis pathways in ALS. In the present review article, we focus on recent studies that report molecular insights of both pathways, and discuss the possibility that energy dysfunction might negatively regulate RNA homeostasis via the impairment of cytoplasmic-nuclear shuttling in motor neurons and subsequently contribute to the development of ALS.
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Affiliation(s)
- Yu-Ju Liu
- Division of Neuroscience, Institute of Biomedical Sciences, Academia SinicaTaipei, Taiwan
| | - Po-Yi Tsai
- Division of Neuroscience, Institute of Biomedical Sciences, Academia SinicaTaipei, Taiwan
| | - Yijuang Chern
- Division of Neuroscience, Institute of Biomedical Sciences, Academia SinicaTaipei, Taiwan
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18
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Could Sirtuin Activities Modify ALS Onset and Progression? Cell Mol Neurobiol 2016; 37:1147-1160. [PMID: 27942908 DOI: 10.1007/s10571-016-0452-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 11/30/2016] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a complex etiology. Sirtuins have been implicated as disease-modifying factors in several neurological disorders, and in the past decade, attempts have been made to check if manipulating Sirtuin activities and levels could confer benefit in terms of neuroprotection and survival in ALS models. The efforts have largely focused on mutant SOD1, and while limited in scope, the results were largely positive. Here, the body of work linking Sirtuins with ALS is reviewed, with discussions on how Sirtuins and their activities may impact on the major etiological mechanisms of ALS. Moving forward, it is important that the potentially beneficial effect of Sirtuins in ALS disease onset and progression are assessed in ALS models with TDP-43, FUS, and C9orf72 mutations.
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Ratti A, Buratti E. Physiological functions and pathobiology of TDP-43 and FUS/TLS proteins. J Neurochem 2016; 138 Suppl 1:95-111. [PMID: 27015757 DOI: 10.1111/jnc.13625] [Citation(s) in RCA: 252] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/19/2016] [Accepted: 03/22/2016] [Indexed: 12/12/2022]
Abstract
The multiple roles played by RNA binding proteins in neurodegeneration have become apparent following the discovery of TAR DNA binding protein 43 kDa (TDP-43) and fused in sarcoma/translocated in liposarcoma (FUS/TLS) involvement in amyotrophic lateral sclerosis and frontotemporal lobar dementia. In these two diseases, the majority of patients display the presence of aggregated forms of one of these proteins in their brains. The study of their functional properties currently represents a very promising target for developing the effective therapeutic options that are still lacking. This aim, however, must be preceded by an accurate evaluation of TDP-43 and FUS/TLS biological functions, both in physiological and disease conditions. Recent findings have uncovered several aspects of RNA metabolism that can be affected by misregulation of these two proteins. Progress has also been made in starting to understand how the aggregation of these proteins occurs and spreads from cell to cell. The aim of this review will be to provide a general overview of TDP-43 and FUS/TLS proteins and to highlight their physiological functions. At present, the emerging picture is that TDP-43 and FUS/TLS control several aspects of an mRNA's life, but they can also participate in DNA repair processes and in non-coding RNA metabolism. Although their regulatory activities are similar, they regulate mainly distinct RNA targets and show different pathogenetic mechanisms in amyotrophic lateral sclerosis/frontotemporal lobar dementia diseases. The identification of key events in these processes represents today the best chance of finding targetable options for therapeutic approaches that might actually make a difference at the clinical level. The two major RNA Binding Proteins involved in Amyotrophic Lateral Sclerosisi and Frontotemporal Dementia are TDP-43 and FUST/TLS. Both proteins are involved in regulating all aspects of RNA and RNA life cycle within neurons, from transcription, processing, and transport/stability to the formation of cytoplasmic and nuclear stress granules. For this reason, the aberrant aggregation of these factors during disease can impair multiple RNA metabolic pathways and eventually lead to neuronal death/inactivation. The purpose of this review is to provide an up-to-date perspective on what we know about this issue at the molecular level. This article is part of the Frontotemporal Dementia special issue.
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Affiliation(s)
- Antonia Ratti
- Department of Pathophysiology and Transplantation, 'Dino Ferrari' Center - Università degli Studi di Milano, Milan, Italy.,Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
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Langellotti S, Romano V, Romano G, Klima R, Feiguin F, Cragnaz L, Romano M, Baralle FE. A novel Drosophila model of TDP-43 proteinopathies: N-terminal sequences combined with the Q/N domain induce protein functional loss and locomotion defects. Dis Model Mech 2016; 9:659-69. [PMID: 27101846 PMCID: PMC4920146 DOI: 10.1242/dmm.023382] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 04/20/2016] [Indexed: 12/12/2022] Open
Abstract
Transactive response DNA-binding protein 43 kDa (TDP-43, also known as TBPH in Drosophila melanogaster and TARDBP in mammals) is the main protein component of the pathological inclusions observed in neurons of patients affected by different neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and fronto-temporal lobar degeneration (FTLD). The number of studies investigating the molecular mechanisms underlying neurodegeneration is constantly growing; however, the role played by TDP-43 in disease onset and progression is still unclear. A fundamental shortcoming that hampers progress is the lack of animal models showing aggregation of TDP-43 without overexpression. In this manuscript, we have extended our cellular model of aggregation to a transgenic Drosophila line. Our fly model is not based on the overexpression of a wild-type TDP-43 transgene. By contrast, we engineered a construct that includes only the specific TDP-43 amino acid sequences necessary to trigger aggregate formation and capable of trapping endogenous Drosophila TDP-43 into a non-functional insoluble form. Importantly, the resulting recombinant product lacks functional RNA recognition motifs (RRMs) and, thus, does not have specific TDP-43-physiological functions (i.e. splicing regulation ability) that might affect the animal phenotype per se. This novel Drosophila model exhibits an evident degenerative phenotype with reduced lifespan and early locomotion defects. Additionally, we show that important proteins involved in neuromuscular junction function, such as syntaxin (SYX), decrease their levels as a consequence of TDP-43 loss of function implying that the degenerative phenotype is a consequence of TDP-43 sequestration into the aggregates. Our data lend further support to the role of TDP-43 loss-of-function in the pathogenesis of neurodegenerative disorders. The novel transgenic Drosophila model presented in this study will help to gain further insight into the molecular mechanisms underlying neurodegeneration and will provide a valuable system to test potential therapeutic agents to counteract disease. Summary: An engineered TDP-43 construct can be used to induce TDP-43 aggregation in Drosophila, providing a model that could be useful for characterization of pathogenetic mechanisms and drug screening.
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Affiliation(s)
- Simona Langellotti
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste I-34149, Italy
| | - Valentina Romano
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste I-34149, Italy
| | - Giulia Romano
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste I-34149, Italy
| | - Raffaella Klima
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste I-34149, Italy
| | - Fabian Feiguin
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste I-34149, Italy
| | - Lucia Cragnaz
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste I-34149, Italy
| | - Maurizio Romano
- Department of Life Sciences, University of Trieste, Via A. Valerio 28, Trieste 34127, Italy
| | - Francisco E Baralle
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, Trieste I-34149, Italy
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Lim L, Wei Y, Lu Y, Song J. ALS-Causing Mutations Significantly Perturb the Self-Assembly and Interaction with Nucleic Acid of the Intrinsically Disordered Prion-Like Domain of TDP-43. PLoS Biol 2016; 14:e1002338. [PMID: 26735904 PMCID: PMC4703307 DOI: 10.1371/journal.pbio.1002338] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 11/25/2015] [Indexed: 12/13/2022] Open
Abstract
TAR-DNA-binding protein-43 (TDP-43) C-terminus encodes a prion-like domain widely presented in RNA-binding proteins, which functions to form dynamic oligomers and also, amazingly, hosts most amyotrophic lateral sclerosis (ALS)-causing mutations. Here, as facilitated by our previous discovery, by circular dichroism (CD), fluorescence and nuclear magnetic resonance (NMR) spectroscopy, we have successfully determined conformations, dynamics, and self-associations of the full-length prion-like domains of the wild type and three ALS-causing mutants (A315E, Q331K, and M337V) in both aqueous solutions and membrane environments. The study decodes the following: (1) The TDP-43 prion-like domain is intrinsically disordered only with some nascent secondary structures in aqueous solutions, but owns the capacity to assemble into dynamic oligomers rich in β-sheet structures. By contrast, despite having highly similar conformations, three mutants gained the ability to form amyloid oligomers. The wild type and three mutants all formed amyloid fibrils after incubation as imaged by electron microscopy. (2) The interaction with nucleic acid enhances the self-assembly for the wild type but triggers quick aggregation for three mutants. (3) A membrane-interacting subdomain has been identified over residues Met311-Gln343 indispensable for TDP-43 neurotoxicity, which transforms into a well-folded Ω-loop-helix structure in membrane environments. Furthermore, despite having very similar membrane-embedded conformations, three mutants will undergo further self-association in the membrane environment. Our study implies that the TDP-43 prion-like domain appears to have an energy landscape, which allows the assembly of the wild-type sequence into dynamic oligomers only under very limited condition sets, and ALS-causing point mutations are sufficient to remodel it to more favor the amyloid formation or irreversible aggregation, thus supporting the emerging view that the pathologic aggregation may occur via the exaggeration of functionally important assemblies. Furthermore, the coupled capacity of TDP-43 in aggregation and membrane interaction may critically account for its high neurotoxicity, and therefore its decoupling may represent a promising therapeutic strategy to treat TDP-43 causing neurodegenerative diseases. The prion-like domain of TDP-43 appears to have an energy landscape that allows oligomerisation only under very limited conditions; however, TDP-43 mutations that cause amyotrophic lateral sclerosis are sufficient to remodel the protein in favor of amyloid formation. Amyotrophic lateral sclerosis (ALS) is the most prevalent fatal motor neuron disease. It was identified ~140 years ago, but the exact mechanism underlying the disease has still not been well defined. TAR-DNA-binding protein-43 (TDP-43) was identified as the major component of the proteinaceous inclusions present in ~97% ALS and ~45% frontotemporal dementia (FTD) patients, and has also been observed in an increasing spectrum of other neurodegenerative disorders, including Alzheimer disease. The TDP-43 C-terminus is a key domain—it encodes a prion-like domain and, crucially, hosts almost all ALS-causing mutations. Here we have successfully determined the conformations, dynamics, and self-associations of the prion-like domains of both wild type and three ALS-causing mutants in both aqueous solutions and membrane environments. The study suggests that the TDP-43 prion-like domain appears to have a unique energy landscape, which allows the assembly of the wild-type sequence into specific oligomers only under very limited conditions. Intriguingly, ALS-causing point mutations remodel the energy landscape to favor amyloid formation or irreversible aggregation, thus supporting the emerging view that pathologic aggregation may occur via the exaggeration of functionally important assemblies. Furthermore, the coupled capacity of TDP-43 in aggregation and membrane interaction may partly account for its high neurotoxicity; decoupling these may therefore represent a promising therapeutic strategy to treat TDP-43-mediated neurodegenerative diseases.
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Affiliation(s)
- Liangzhong Lim
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
| | - Yuanyuan Wei
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore
| | - Yimei Lu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
| | - Jianxing Song
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore
- * E-mail:
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Cragnaz L, Klima R, De Conti L, Romano G, Feiguin F, Buratti E, Baralle M, Baralle FE. An age-related reduction of brain TBPH/TDP-43 levels precedes the onset of locomotion defects in a Drosophila ALS model. Neuroscience 2015; 311:415-21. [PMID: 26518462 DOI: 10.1016/j.neuroscience.2015.10.037] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/19/2015] [Accepted: 10/21/2015] [Indexed: 11/27/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. The average age of onset of both sporadic and familial cases is 50-60 years of age. The presence of cytoplasmic inclusions of the RNA-binding protein TAR DNA-binding protein-43 (TDP-43) in the affected neurons is seen in 95% of the ALS cases, which results in TDP-43 nuclear clearance and loss of function. The Drosophila melanogaster ortholog of TDP-43 (TBPH) shares many characteristics with the human protein. Using a TDP-43 aggregation inducer previously developed in human cells, we created a transgenic fly that shows an adult locomotive defect. Phenotype onset correlates with a physiologically age-related drop of TDP-43/TBPH mRNA and protein levels, seen both in mice and flies. Artificial reduction of mRNA levels, in vivo, anticipates the locomotion defect to the larval stage. Our study links, for the first time, aggregation and the age-related, evolutionary conserved reduction of TDP-43/TBPH levels with the onset of an ALS-like locomotion defect in a Drosophila model. A similar process might trigger the human disease.
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Affiliation(s)
- L Cragnaz
- ICGEB - International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - R Klima
- ICGEB - International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - L De Conti
- ICGEB - International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - G Romano
- ICGEB - International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - F Feiguin
- ICGEB - International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - E Buratti
- ICGEB - International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - M Baralle
- ICGEB - International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy
| | - F E Baralle
- ICGEB - International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149 Trieste, Italy.
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Tao Z, Wang H, Xia Q, Li K, Li K, Jiang X, Xu G, Wang G, Ying Z. Nucleolar stress and impaired stress granule formation contribute to C9orf72 RAN translation-induced cytotoxicity. Hum Mol Genet 2015; 24:2426-41. [PMID: 25575510 DOI: 10.1093/hmg/ddv005] [Citation(s) in RCA: 178] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 01/06/2015] [Indexed: 12/14/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are the two common neurodegenerative diseases that have been associated with the GGGGCC·GGCCCC repeat RNA expansion in a noncoding region of C9orf72. It has been previously reported that unconventional repeat-associated non-ATG (RAN) translation of GGGGCC·GGCCCC repeats produces five types of dipeptide-repeat proteins (referred to as RAN proteins): poly-glycine-alanine (GA), poly-glycine-proline (GP), poly-glycine-arginine (GR), poly-proline-arginine (PR) and poly-proline-alanine (PA). Although protein aggregates of RAN proteins have been found in patients, it is unclear whether RAN protein aggregation induces neurotoxicity. In the present study, we aimed to understand the biological properties of all five types of RAN proteins. Surprisingly, our results showed that none of these RAN proteins was aggregate-prone in our cellular model and that the turnover of these RAN proteins was not affected by the ubiquitin-proteasome system or autophagy. Moreover, poly-GR and poly-PR, but not poly-GA, poly-GP or poly-PA, localized to the nucleolus and induced the translocation of the key nucleolar component nucleophosmin, leading to nucleolar stress and cell death. This poly-GR- and poly-PR-mediated defect in nucleolar function was associated with the suppression of ribosomal RNA synthesis and the impairment of stress granule formation. Taken together, the results of the present study suggest a simple model of the molecular mechanisms underlying RAN translation-mediated cytotoxicity in C9orf72-linked ALS/FTD in which nucleolar stress, but not protein aggregation, is the primary contributor to C9orf72-linked neurodegeneration.
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Affiliation(s)
- Zhouteng Tao
- Laboratory of Molecular Neuropathology, Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences
| | - Hongfeng Wang
- Laboratory of Molecular Neuropathology, Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences
| | - Qin Xia
- Laboratory of Molecular Neuropathology, Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences
| | - Ke Li
- Laboratory of Molecular Neuropathology, Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences
| | - Kai Li
- Department of Pharmacology, College of Pharmaceutical Sciences
| | - Xiaogang Jiang
- Department of Pharmacology, College of Pharmaceutical Sciences
| | - Guoqiang Xu
- Laboratory of Chemical Biology, Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences
| | - Guanghui Wang
- Laboratory of Molecular Neuropathology, Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences, Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230027, China
| | - Zheng Ying
- Laboratory of Molecular Neuropathology, Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215021, China and
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