1
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Zubčić K, Franić D, Pravica M, Hof PR, Šimić G, Boban M. Effects of heterologous human tau protein expression in yeast models of proteotoxic stress response. CNS Neurosci Ther 2024; 30:e14304. [PMID: 37341072 PMCID: PMC11163194 DOI: 10.1111/cns.14304] [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] [Received: 04/10/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/22/2023] Open
Abstract
BACKGROUND The primary histological characteristic of Alzheimer's disease is the presence of neurofibrillary tangles, which are large aggregates of tau protein. Aging is the primary risk factor for the development of Alzheimer's disease, however, the underlying causes of tau protein aggregation and toxicity are unclear. AIMS Here we investigated tau aggregation and toxicity under the conditions of compromised protein homeostasis. METHODS We used heterologous expression of human tau protein in the unicellular eukaryote yeast Saccharomyces cerevisiae with evolutionarily conserved protein quality control pathways and examined tau-dependent toxicity and aggregation using growth assays, fluorescence microscopy, and a split luciferase-based reporter NanoBiT. RESULTS Tau protein expressed in yeast under mild proteotoxic stress, or in mutants with impaired pathways for proteotoxic stress response, did not lead to synthetic toxicity or the formation of obvious aggregates. Chronologically old cells also did not develop observable tau aggregates. Our examination of tau oligomerization in living cells using NanoBiT reporter suggests that tau does not form significant levels of oligomers under basal conditions or under mild proteotoxic stress. CONCLUSION Together our data suggest that human tau protein does not represent a major burden to the protein quality control system in yeast cells.
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Affiliation(s)
- Klara Zubčić
- Croatian Institute for Brain Research, University of Zagreb School of MedicineZagrebCroatia
| | - Dina Franić
- Croatian Institute for Brain Research, University of Zagreb School of MedicineZagrebCroatia
| | - Mihaela Pravica
- Croatian Institute for Brain Research, University of Zagreb School of MedicineZagrebCroatia
| | - Patrick R. Hof
- Nash Family Department of Neuroscience, Ronald M. Loeb Center for Alzheimer's DiseaseFriedman Brain Institute, Icahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Goran Šimić
- Croatian Institute for Brain Research, University of Zagreb School of MedicineZagrebCroatia
| | - Mirta Boban
- Croatian Institute for Brain Research, University of Zagreb School of MedicineZagrebCroatia
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2
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C9orf72 dipeptides disrupt the nucleocytoplasmic transport machinery and cause TDP-43 mislocalisation to the cytoplasm. Sci Rep 2022; 12:4799. [PMID: 35314728 PMCID: PMC8938440 DOI: 10.1038/s41598-022-08724-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 03/01/2022] [Indexed: 12/03/2022] Open
Abstract
A repeat expansion in C9orf72 is the major cause of both frontotemporal dementia and amyotrophic lateral sclerosis, accounting for approximately 1 in 12 cases of either disease. The expansion is translated to produce five dipeptide repeat proteins (DPRs) which aggregate in patient brain and are toxic in numerous models, though the mechanisms underlying this toxicity are poorly understood. Recent studies highlight nucleocytoplasmic transport impairments as a potential mechanism underlying neurodegeneration in C9orf72-linked disease, although the contribution of DPRs to this remains unclear. We expressed DPRs in HeLa cells, in the absence of repeat RNA. Crucially, we expressed DPRs at repeat-lengths found in patients (> 1000 units), ensuring our findings were relevant to disease. Immunofluorescence imaging was used to investigate the impact of each DPR on the nucleus, nucleocytoplasmic transport machinery and TDP-43 localisation. DPRs impaired the structural integrity of the nucleus, causing nuclear membrane disruption and misshapen nuclei. Ran and RanGAP, two proteins required for nucleocytoplasmic transport, were also mislocalised in DPR-expressing cells. Furthermore, DPRs triggered mislocalisation of TDP-43 to the cytoplasm, and this occurred in the same cells as Ran and RanGAP mislocalisation, suggesting a potential link between DPRs, nucleocytoplasmic transport impairments and TDP-43 pathology.
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3
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Jiang L, Zhang T, Lu K, Qi S. The progress in C9orf72 research: ALS/FTD pathogenesis, functions and structure. Small GTPases 2022; 13:56-76. [PMID: 33663328 PMCID: PMC9707547 DOI: 10.1080/21541248.2021.1892443] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The hexanucleotide repeat (GGGGCC) expansion in C9orf72 is accounted for a large proportion of the genetic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The hypotheses of how the massive G4C2 repeats in C9orf72 destroy the neurons and lead to ALS/FTD are raised and improving. As a multirole player, C9orf72 exerts critical roles in many cellular processes, including autophagy, membrane trafficking, immune response, and so on. Notably, the partners of C9orf72, through which C9orf72 participates in the cell activities, have been identified. Notably, the structures of the C9orf72-SMCR8-WDR41 complex shed light on its activity as GTPase activating proteins (GAP). In this manuscript, we reviewed the latest research progress in the C9orf72-mediated ALS/FTD, the physiological functions of C9orf72, and the putative function models of C9orf72/C9orf72-containing complex.
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Affiliation(s)
- Lan Jiang
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China
| | - Tizhong Zhang
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China
| | - Kefeng Lu
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China
| | - Shiqian Qi
- Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China,CONTACT Shiqian Qi Department of Urology, State Key Laboratory of Biotherapy, West China Hospital, College of Life Sciences, Sichuan University, Chengdu, China.
These authors contributed equally to this work.
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4
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Ramic M, Andrade NS, Rybin MJ, Esanov R, Wahlestedt C, Benatar M, Zeier Z. Epigenetic Small Molecules Rescue Nucleocytoplasmic Transport and DNA Damage Phenotypes in C9ORF72 ALS/FTD. Brain Sci 2021; 11:brainsci11111543. [PMID: 34827542 PMCID: PMC8616043 DOI: 10.3390/brainsci11111543] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/11/2021] [Accepted: 11/18/2021] [Indexed: 01/04/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disease with available treatments only marginally slowing progression or improving survival. A hexanucleotide repeat expansion mutation in the C9ORF72 gene is the most commonly known genetic cause of both sporadic and familial cases of ALS and frontotemporal dementia (FTD). The C9ORF72 expansion mutation produces five dipeptide repeat proteins (DPRs), and while the mechanistic determinants of DPR-mediated neurotoxicity remain incompletely understood, evidence suggests that disruption of nucleocytoplasmic transport and increased DNA damage contributes to pathology. Therefore, characterizing these disturbances and determining the relative contribution of different DPRs is needed to facilitate the development of novel therapeutics for C9ALS/FTD. To this end, we generated a series of nucleocytoplasmic transport “biosensors”, composed of the green fluorescent protein (GFP), fused to different classes of nuclear localization signals (NLSs) and nuclear export signals (NESs). Using these biosensors in conjunction with automated microscopy, we investigated the role of the three most neurotoxic DPRs (PR, GR, and GA) on seven nuclear import and two export pathways. In addition to other DPRs, we found that PR had pronounced inhibitory effects on the classical nuclear export pathway and several nuclear import pathways. To identify compounds capable of counteracting the effects of PR on nucleocytoplasmic transport, we developed a nucleocytoplasmic transport assay and screened several commercially available compound libraries, totaling 2714 compounds. In addition to restoring nucleocytoplasmic transport efficiencies, hits from the screen also counteract the cytotoxic effects of PR. Selected hits were subsequently tested for their ability to rescue another C9ALS/FTD phenotype—persistent DNA double strand breakage. Overall, we found that DPRs disrupt multiple nucleocytoplasmic transport pathways and we identified small molecules that counteract these effects—resulting in increased viability of PR-expressing cells and decreased DNA damage markers in patient-derived motor neurons. Several HDAC inhibitors were validated as hits, supporting previous studies that show that HDAC inhibitors confer therapeutic effects in neurodegenerative models.
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Affiliation(s)
- Melina Ramic
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Nadja S. Andrade
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Matthew J. Rybin
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Rustam Esanov
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Claes Wahlestedt
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
| | - Michael Benatar
- Department of Neurology, University of Miami Miller School of Medicine, 1120 NW 14th St., Miami, FL 33136, USA;
| | - Zane Zeier
- Center for Therapeutic Innovation, Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, 1501 NW 10th Ave, Miami, FL 33136, USA; (M.R.); (N.S.A.); (M.J.R.); (R.E.); (C.W.)
- Correspondence: ; Tel.: +1-305-243-1367
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5
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The nuclear ubiquitin ligase adaptor SPOP is a conserved regulator of C9orf72 dipeptide toxicity. Proc Natl Acad Sci U S A 2021; 118:2104664118. [PMID: 34593637 DOI: 10.1073/pnas.2104664118] [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] [Accepted: 08/06/2021] [Indexed: 12/29/2022] Open
Abstract
A hexanucleotide repeat expansion in the C9orf72 gene is the most common cause of inherited amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Unconventional translation of the C9orf72 repeat produces dipeptide repeat proteins (DPRs). Previously, we showed that the DPRs PR50 and GR50 are highly toxic when expressed in Caenorhabditis elegans, and this toxicity depends on nuclear localization of the DPR. In an unbiased genome-wide RNA interference (RNAi) screen for suppressors of PR50 toxicity, we identified 12 genes that consistently suppressed either the developmental arrest and/or paralysis phenotype evoked by PR50 expression. All of these genes have vertebrate homologs, and 7 of 12 contain predicted nuclear localization signals. One of these genes was spop-1, the C. elegans homolog of SPOP, a nuclear localized E3 ubiquitin ligase adaptor only found in metazoans. SPOP is also required for GR50 toxicity and functions in a genetic pathway that includes cul-3, which is the canonical E3 ligase partner for SPOP Genetic or pharmacological inhibition of SPOP in mammalian primary spinal cord motor neurons suppressed DPR toxicity without affecting DPR expression levels. Finally, we find that knockdown of bromodomain proteins in both C. elegans and mammalian neurons, which are known SPOP ubiquitination targets, suppresses the protective effect of SPOP inhibition. Together, these data suggest a model in which SPOP promotes the DPR-dependent ubiquitination and degradation of BRD proteins. We speculate the pharmacological manipulation of this pathway, which is currently underway for multiple cancer subtypes, could also represent an entry point for therapeutic intervention to treat C9orf72 FTD/ALS.
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6
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Lafarga V, Sirozh O, Díaz-López I, Galarreta A, Hisaoka M, Zarzuela E, Boskovic J, Jovanovic B, Fernandez-Leiro R, Muñoz J, Stoecklin G, Ventoso I, Fernandez-Capetillo O. Widespread displacement of DNA- and RNA-binding factors underlies toxicity of arginine-rich cell-penetrating peptides. EMBO J 2021; 40:e103311. [PMID: 33978236 DOI: 10.15252/embj.2019103311] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 04/13/2021] [Accepted: 04/20/2021] [Indexed: 11/09/2022] Open
Abstract
Due to their capability to transport chemicals or proteins into target cells, cell-penetrating peptides (CPPs) are being developed as therapy delivery tools. However, and despite their interesting properties, arginine-rich CPPs often show toxicity for reasons that remain poorly understood. Using a (PR)n dipeptide repeat that has been linked to amyotrophic lateral sclerosis (ALS) as a model of an arginine-rich CPP, we here show that the presence of (PR)n leads to a generalized displacement of RNA- and DNA-binding proteins from chromatin and mRNA. Accordingly, any reaction involving nucleic acids, such as RNA transcription, translation, splicing and degradation, or DNA replication and repair, is impaired by the presence of the CPPs. Interestingly, the effects of (PR)n are fully mimicked by protamine, a small arginine-rich protein that displaces histones from chromatin during spermatogenesis. We propose that widespread coating of nucleic acids and consequent displacement of RNA- and DNA-binding factors from chromatin and mRNA accounts for the toxicity of arginine-rich CPPs, including those that have been recently associated with the onset of ALS.
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Affiliation(s)
- Vanesa Lafarga
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Oleksandra Sirozh
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Irene Díaz-López
- Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), Departamento de Biología Molecular, Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Antonio Galarreta
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Misaru Hisaoka
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, National Center for Tumor Diseases (NCT), Heidelberg, Germany
| | - Eduardo Zarzuela
- ProteoRed-ISCIII, Proteomics Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Jasminka Boskovic
- Electron Microscopy Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Bogdan Jovanovic
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, National Center for Tumor Diseases (NCT), Heidelberg, Germany
| | - Rafael Fernandez-Leiro
- Genomic Integrity and Structural Biology Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Jaime Muñoz
- ProteoRed-ISCIII, Proteomics Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Georg Stoecklin
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, National Center for Tumor Diseases (NCT), Heidelberg, Germany
| | - Iván Ventoso
- Centro de Biología Molecular 'Severo Ochoa' (CSIC-UAM), Departamento de Biología Molecular, Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Oscar Fernandez-Capetillo
- Genomic Instability Group, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.,Science for Life Laboratory, Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
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7
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Solomon DA, Smikle R, Reid MJ, Mizielinska S. Altered Phase Separation and Cellular Impact in C9orf72-Linked ALS/FTD. Front Cell Neurosci 2021; 15:664151. [PMID: 33967699 PMCID: PMC8096919 DOI: 10.3389/fncel.2021.664151] [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] [Received: 02/04/2021] [Accepted: 03/19/2021] [Indexed: 12/21/2022] Open
Abstract
Since the discovery of the C9orf72 repeat expansion mutation as causative for chromosome 9-linked amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in 2011, a multitude of cellular pathways have been implicated. However, evidence has also been accumulating for a key mechanism of cellular compartmentalization—phase separation. Liquid-liquid phase separation (LLPS) is fundamental for the formation of membraneless organelles including stress granules, the nucleolus, Cajal bodies, nuclear speckles and the central channel of the nuclear pore. Evidence has now accumulated showing that the formation and function of these membraneless organelles is impaired by both the toxic arginine rich dipeptide repeat proteins (DPRs), translated from the C9orf72 repeat RNA transcript, and the repeat RNA itself. Both the arginine rich DPRs and repeat RNA themselves undergo phase separation and disrupt the physiological phase separation of proteins involved in the formation of these liquid-like organelles. Hence abnormal phase separation may explain a number of pathological cellular phenomena associated with C9orf72-ALS/FTD. In this review article, we will discuss the principles of phase separation, phase separation of the DPRs and repeat RNA themselves and how they perturb LLPS associated with membraneless organelles and the functional consequences of this. We will then discuss how phase separation may impact the major pathological feature of C9orf72-ALS/FTD, TDP-43 proteinopathy, and how LLPS may be targeted therapeutically in disease.
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Affiliation(s)
- Daniel A Solomon
- UK Dementia Research Institute at King's College London, London, United Kingdom.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Rebekah Smikle
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Matthew J Reid
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Sarah Mizielinska
- UK Dementia Research Institute at King's College London, London, United Kingdom.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
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8
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Peggion C, Massimino ML, Stella R, Bortolotto R, Agostini J, Maldi A, Sartori G, Tonello F, Bertoli A, Lopreiato R. Nucleolin Rescues TDP-43 Toxicity in Yeast and Human Cell Models. Front Cell Neurosci 2021; 15:625665. [PMID: 33912014 PMCID: PMC8072491 DOI: 10.3389/fncel.2021.625665] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/18/2021] [Indexed: 12/12/2022] Open
Abstract
TDP-43 is a nuclear protein involved in pivotal processes, extensively studied for its implication in neurodegenerative disorders. TDP-43 cytosolic inclusions are a common neuropathologic hallmark in amyotrophic lateral sclerosis (ALS) and related diseases, and it is now established that TDP-43 misfolding and aggregation play a key role in their etiopathology. TDP-43 neurotoxic mechanisms are not yet clarified, but the identification of proteins able to modulate TDP-43-mediated damage may be promising therapeutic targets for TDP-43 proteinopathies. Here we show by the use of refined yeast models that the nucleolar protein nucleolin (NCL) acts as a potent suppressor of TDP-43 toxicity, restoring cell viability. We provide evidence that NCL co-expression is able to alleviate TDP-43-induced damage also in human cells, further supporting its beneficial effects in a more consistent pathophysiological context. Presented data suggest that NCL could promote TDP-43 nuclear retention, reducing the formation of toxic cytosolic TDP-43 inclusions.
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Affiliation(s)
- Caterina Peggion
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Roberto Stella
- Food Safety Division, Department of Chemistry, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | - Raissa Bortolotto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Jessica Agostini
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Arianna Maldi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Geppo Sartori
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Alessandro Bertoli
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,CNR - Neuroscience Institute, Padova, Italy.,Padova Neuroscience Center, University of Padova, Padova, Italy
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9
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Wang JC, Ramaswami G, Geschwind DH. Gene co-expression network analysis in human spinal cord highlights mechanisms underlying amyotrophic lateral sclerosis susceptibility. Sci Rep 2021; 11:5748. [PMID: 33707641 PMCID: PMC7970949 DOI: 10.1038/s41598-021-85061-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 01/14/2021] [Indexed: 12/23/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease defined by motor neuron (MN) loss. Multiple genetic risk factors have been identified, implicating RNA and protein metabolism and intracellular transport, among other biological mechanisms. To achieve a systems-level understanding of the mechanisms governing ALS pathophysiology, we built gene co-expression networks using RNA-sequencing data from control human spinal cord samples, identifying 13 gene co-expression modules, each of which represents a distinct biological process or cell type. Analysis of four RNA-seq datasets from a range of ALS disease-associated contexts reveal dysregulation in numerous modules related to ribosomal function, wound response, and leukocyte activation, implicating astrocytes, oligodendrocytes, endothelia, and microglia in ALS pathophysiology. To identify potentially causal processes, we partitioned heritability across the genome, finding that ALS common genetic risk is enriched within two specific modules, SC.M4, representing genes related to RNA processing and gene regulation, and SC.M2, representing genes related to intracellular transport and autophagy and enriched in oligodendrocyte markers. Top hub genes of this latter module include ALS-implicated risk genes such as KPNA3, TMED2, and NCOA4, the latter of which regulates ferritin autophagy, implicating this process in ALS pathophysiology. These unbiased, genome-wide analyses confirm the utility of a systems approach to understanding the causes and drivers of ALS.
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Affiliation(s)
- Jerry C Wang
- Program in Neurogenetics, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Gokul Ramaswami
- Program in Neurogenetics, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Daniel H Geschwind
- Program in Neurogenetics, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA. .,Center for Autism Research and Treatment, Semel Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA. .,Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA. .,Institute for Precision Health, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.
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10
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Jagaraj CJ, Parakh S, Atkin JD. Emerging Evidence Highlighting the Importance of Redox Dysregulation in the Pathogenesis of Amyotrophic Lateral Sclerosis (ALS). Front Cell Neurosci 2021; 14:581950. [PMID: 33679322 PMCID: PMC7929997 DOI: 10.3389/fncel.2020.581950] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 12/21/2020] [Indexed: 12/20/2022] Open
Abstract
The cellular redox state, or balance between cellular oxidation and reduction reactions, serves as a vital antioxidant defence system that is linked to all important cellular activities. Redox regulation is therefore a fundamental cellular process for aerobic organisms. Whilst oxidative stress is well described in neurodegenerative disorders including amyotrophic lateral sclerosis (ALS), other aspects of redox dysfunction and their contributions to pathophysiology are only just emerging. ALS is a fatal neurodegenerative disease affecting motor neurons, with few useful treatments. Hence there is an urgent need to develop more effective therapeutics in the future. Here, we discuss the increasing evidence for redox dysregulation as an important and primary contributor to ALS pathogenesis, which is associated with multiple disease mechanisms. Understanding the connection between redox homeostasis, proteins that mediate redox regulation, and disease pathophysiology in ALS, may facilitate a better understanding of disease mechanisms, and lead to the design of better therapeutic strategies.
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Affiliation(s)
- Cyril Jones Jagaraj
- Department of Biomedical Sciences, Macquarie University Centre for MND Research, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Sonam Parakh
- Department of Biomedical Sciences, Macquarie University Centre for MND Research, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Julie D Atkin
- Department of Biomedical Sciences, Macquarie University Centre for MND Research, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, Australia
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11
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Bitetto G, Di Fonzo A. Nucleo-cytoplasmic transport defects and protein aggregates in neurodegeneration. Transl Neurodegener 2020; 9:25. [PMID: 32616075 PMCID: PMC7333321 DOI: 10.1186/s40035-020-00205-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 06/01/2020] [Indexed: 02/06/2023] Open
Abstract
In the ongoing process of uncovering molecular abnormalities in neurodegenerative diseases characterized by toxic protein aggregates, nucleo-cytoplasmic transport defects have an emerging role. Several pieces of evidence suggest a link between neuronal protein inclusions and nuclear pore complex (NPC) damage. These processes lead to oxidative stress, inefficient transcription, and aberrant DNA/RNA maintenance. The clinical and neuropathological spectrum of NPC defects is broad, ranging from physiological aging to a suite of neurodegenerative diseases. A better understanding of the shared pathways among these conditions may represent a significant step toward dissecting their underlying molecular mechanisms, opening the way to a real possibility of identifying common therapeutic targets.
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Affiliation(s)
- Giacomo Bitetto
- IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Alessio Di Fonzo
- IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Via Francesco Sforza 35, 20122, Milan, Italy.
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12
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Chernoff YO, Grizel AV, Rubel AA, Zelinsky AA, Chandramowlishwaran P, Chernova TA. Application of yeast to studying amyloid and prion diseases. ADVANCES IN GENETICS 2020; 105:293-380. [PMID: 32560789 PMCID: PMC7527210 DOI: 10.1016/bs.adgen.2020.01.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyloids are fibrous cross-β protein aggregates that are capable of proliferation via nucleated polymerization. Amyloid conformation likely represents an ancient protein fold and is linked to various biological or pathological manifestations. Self-perpetuating amyloid-based protein conformers provide a molecular basis for transmissible (infectious or heritable) protein isoforms, termed prions. Amyloids and prions, as well as other types of misfolded aggregated proteins are associated with a variety of devastating mammalian and human diseases, such as Alzheimer's, Parkinson's and Huntington's diseases, transmissible spongiform encephalopathies (TSEs), amyotrophic lateral sclerosis (ALS) and transthyretinopathies. In yeast and fungi, amyloid-based prions control phenotypically detectable heritable traits. Simplicity of cultivation requirements and availability of powerful genetic approaches makes yeast Saccharomyces cerevisiae an excellent model system for studying molecular and cellular mechanisms governing amyloid formation and propagation. Genetic techniques allowing for the expression of mammalian or human amyloidogenic and prionogenic proteins in yeast enable researchers to capitalize on yeast advantages for characterization of the properties of disease-related proteins. Chimeric constructs employing mammalian and human aggregation-prone proteins or domains, fused to fluorophores or to endogenous yeast proteins allow for cytological or phenotypic detection of disease-related protein aggregation in yeast cells. Yeast systems are amenable to high-throughput screening for antagonists of amyloid formation, propagation and/or toxicity. This review summarizes up to date achievements of yeast assays in application to studying mammalian and human disease-related aggregating proteins, and discusses both limitations and further perspectives of yeast-based strategies.
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Affiliation(s)
- Yury O Chernoff
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States; Laboratory of Amyloid Biology, St. Petersburg State University, St. Petersburg, Russia.
| | - Anastasia V Grizel
- Laboratory of Amyloid Biology, St. Petersburg State University, St. Petersburg, Russia
| | - Aleksandr A Rubel
- Laboratory of Amyloid Biology, St. Petersburg State University, St. Petersburg, Russia; Department of Genetics and Biotechnology, St. Petersburg State University, St. Petersburg, Russia; Sirius University of Science and Technology, Sochi, Russia
| | - Andrew A Zelinsky
- Laboratory of Amyloid Biology, St. Petersburg State University, St. Petersburg, Russia
| | | | - Tatiana A Chernova
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, United States
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13
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Fallini C, Khalil B, Smith CL, Rossoll W. Traffic jam at the nuclear pore: All roads lead to nucleocytoplasmic transport defects in ALS/FTD. Neurobiol Dis 2020; 140:104835. [PMID: 32179176 DOI: 10.1016/j.nbd.2020.104835] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/25/2020] [Accepted: 03/12/2020] [Indexed: 02/06/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal late-onset neurodegenerative disease that specifically affects the function and survival of spinal and cortical motor neurons. ALS shares many genetic, clinical, and pathological characteristics with frontotemporal dementia (FTD), and these diseases are now recognized as presentations of a disease spectrum known as ALS/FTD. The molecular determinants of neuronal loss in ALS/FTD are still debated, but the recent discovery of nucleocytoplasmic transport defects as a common denominator of most if not all forms of ALS/FTD has dramatically changed our understanding of the pathogenic mechanisms of this disease. Loss of nuclear pores and nucleoporin aggregation, altered nuclear morphology, and impaired nuclear transport are some of the most prominent features that have been identified using a variety of animal, cellular, and human models of disease. Here, we review the experimental evidence linking nucleocytoplasmic transport defects to the pathogenesis of ALS/FTD and propose a unifying view on how these defects may lead to a vicious cycle that eventually causes neuronal death.
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Affiliation(s)
- Claudia Fallini
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI 02881, USA; Department of Cell and Molecular Biology, University of Rhode Island, Kingston, RI 02881, USA; Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA.
| | - Bilal Khalil
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Courtney L Smith
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Wilfried Rossoll
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.
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14
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Hayes LR, Duan L, Bowen K, Kalab P, Rothstein JD. C9orf72 arginine-rich dipeptide repeat proteins disrupt karyopherin-mediated nuclear import. eLife 2020; 9:e51685. [PMID: 32119645 PMCID: PMC7051184 DOI: 10.7554/elife.51685] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 02/17/2020] [Indexed: 12/13/2022] Open
Abstract
Disruption of nucleocytoplasmic transport is increasingly implicated in the pathogenesis of neurodegenerative diseases, including ALS caused by a C9orf72 hexanucleotide repeat expansion. However, the mechanism(s) remain unclear. Karyopherins, including importin β and its cargo adaptors, have been shown to co-precipitate with the C9orf72 arginine-containing dipeptide repeat proteins (R-DPRs), poly-glycine arginine (GR) and poly-proline arginine (PR), and are protective in genetic modifier screens. Here, we show that R-DPRs interact with importin β, disrupt its cargo loading, and inhibit nuclear import of importin β, importin α/β, and transportin cargoes in permeabilized mouse neurons and HeLa cells, in a manner that can be rescued by RNA. Although R-DPRs induce widespread protein aggregation in this in vitro system, transport disruption is not due to nucleocytoplasmic transport protein sequestration, nor blockade of the phenylalanine-glycine (FG)-rich nuclear pore complex. Our results support a model in which R-DPRs interfere with cargo loading on karyopherins.
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Affiliation(s)
- Lindsey R Hayes
- Department of Neurology, Johns Hopkins University School of MedicineBaltimoreUnited States
- Brain Science Institute, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Lauren Duan
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins UniversityBaltimoreUnited States
| | - Kelly Bowen
- Department of Neurology, Johns Hopkins University School of MedicineBaltimoreUnited States
- Brain Science Institute, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Petr Kalab
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins UniversityBaltimoreUnited States
| | - Jeffrey D Rothstein
- Department of Neurology, Johns Hopkins University School of MedicineBaltimoreUnited States
- Brain Science Institute, Johns Hopkins University School of MedicineBaltimoreUnited States
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15
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Zhao C, Devlin AC, Chouhan AK, Selvaraj BT, Stavrou M, Burr K, Brivio V, He X, Mehta AR, Story D, Shaw CE, Dando O, Hardingham GE, Miles GB, Chandran S. Mutant C9orf72 human iPSC-derived astrocytes cause non-cell autonomous motor neuron pathophysiology. Glia 2019; 68:1046-1064. [PMID: 31841614 PMCID: PMC7078830 DOI: 10.1002/glia.23761] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 11/24/2019] [Accepted: 11/25/2019] [Indexed: 12/12/2022]
Abstract
Mutations in C9orf72 are the most common genetic cause of amyotrophic lateral sclerosis (ALS). Accumulating evidence implicates astrocytes as important non‐cell autonomous contributors to ALS pathogenesis, although the potential deleterious effects of astrocytes on the function of motor neurons remains to be determined in a completely humanized model of C9orf72‐mediated ALS. Here, we use a human iPSC‐based model to study the cell autonomous and non‐autonomous consequences of mutant C9orf72 expression by astrocytes. We show that mutant astrocytes both recapitulate key aspects of C9orf72‐related ALS pathology and, upon co‐culture, cause motor neurons to undergo a progressive loss of action potential output due to decreases in the magnitude of voltage‐activated Na+ and K+ currents. Importantly, CRISPR/Cas‐9 mediated excision of the C9orf72 repeat expansion reverses these phenotypes, confirming that the C9orf72 mutation is responsible for both cell‐autonomous astrocyte pathology and non‐cell autonomous motor neuron pathophysiology.
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Affiliation(s)
- Chen Zhao
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Anna-Claire Devlin
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife, UK
| | - Amit K Chouhan
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife, UK
| | - Bhuvaneish T Selvaraj
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK.,Dementia Research Institute at the University of Edinburgh, Edinburgh, UK
| | - Maria Stavrou
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK.,Dementia Research Institute at the University of Edinburgh, Edinburgh, UK
| | - Karen Burr
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK.,Dementia Research Institute at the University of Edinburgh, Edinburgh, UK
| | - Veronica Brivio
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife, UK
| | - Xin He
- Dementia Research Institute at the University of Edinburgh, Edinburgh, UK.,Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Arpan R Mehta
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK.,Dementia Research Institute at the University of Edinburgh, Edinburgh, UK
| | - David Story
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK.,Dementia Research Institute at the University of Edinburgh, Edinburgh, UK
| | - Christopher E Shaw
- MRC Centre for Neurodegeneration Research, King's College London, Institute of Psychiatry, London, UK.,Dementia Research Institute at Kings College London, Maurice Wohl Clinical Neuroscience Institute, London, UK
| | - Owen Dando
- Dementia Research Institute at the University of Edinburgh, Edinburgh, UK.,Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Giles E Hardingham
- Dementia Research Institute at the University of Edinburgh, Edinburgh, UK.,Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Gareth B Miles
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife, UK
| | - Siddharthan Chandran
- Euan MacDonald Centre for MND Research, The University of Edinburgh, Edinburgh, UK.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK.,Dementia Research Institute at the University of Edinburgh, Edinburgh, UK.,Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
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16
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Dickson DW, Baker MC, Jackson JL, DeJesus-Hernandez M, Finch NA, Tian S, Heckman MG, Pottier C, Gendron TF, Murray ME, Ren Y, Reddy JS, Graff-Radford NR, Boeve BF, Petersen RC, Knopman DS, Josephs KA, Petrucelli L, Oskarsson B, Sheppard JW, Asmann YW, Rademakers R, van Blitterswijk M. Extensive transcriptomic study emphasizes importance of vesicular transport in C9orf72 expansion carriers. Acta Neuropathol Commun 2019; 7:150. [PMID: 31594549 PMCID: PMC6781370 DOI: 10.1186/s40478-019-0797-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 08/24/2019] [Indexed: 12/12/2022] Open
Abstract
The majority of the clinico-pathological variability observed in patients harboring a repeat expansion in the C9orf72-SMCR8 complex subunit (C9orf72) remains unexplained. This expansion, which represents the most common genetic cause of frontotemporal lobar degeneration (FTLD) and motor neuron disease (MND), results in a loss of C9orf72 expression and the generation of RNA foci and dipeptide repeat (DPR) proteins. The C9orf72 protein itself plays a role in vesicular transport, serving as a guanine nucleotide exchange factor that regulates GTPases. To further elucidate the mechanisms underlying C9orf72-related diseases and to identify potential disease modifiers, we performed an extensive RNA sequencing study. We included individuals for whom frontal cortex tissue was available: FTLD and FTLD/MND patients with (n = 34) or without (n = 44) an expanded C9orf72 repeat as well as control subjects (n = 24). In total, 6706 genes were differentially expressed between these groups (false discovery rate [FDR] < 0.05). The top gene was C9orf72 (FDR = 1.41E-14), which was roughly two-fold lower in C9orf72 expansion carriers than in (disease) controls. Co-expression analysis revealed groups of correlated genes (modules) that were enriched for processes such as protein folding, RNA splicing, synaptic signaling, metabolism, and Golgi vesicle transport. Within our cohort of C9orf72 expansion carriers, machine learning uncovered interesting candidates associated with clinico-pathological features, including age at onset (vascular endothelial growth factor A [VEGFA]), C9orf72 expansion size (cyclin dependent kinase like 1 [CDKL1]), DPR protein levels (eukaryotic elongation factor 2 kinase [EEF2K]), and survival after onset (small G protein signaling modulator 3 [SGSM3]). Given the fact that we detected a module involved in vesicular transport in addition to a GTPase activator (SGSM3) as a potential modifier, our findings seem to suggest that the presence of a C9orf72 repeat expansion might hamper vesicular transport and that genes affecting this process may modify the phenotype of C9orf72-linked diseases.
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Affiliation(s)
- Dennis W. Dickson
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Matthew C. Baker
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Jazmyne L. Jackson
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | | | - NiCole A. Finch
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Shulan Tian
- Department of Health Sciences Research, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 USA
| | - Michael G. Heckman
- Division of Biomedical Statistics and Informatics, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Cyril Pottier
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Tania F. Gendron
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Melissa E. Murray
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Yingxue Ren
- Department of Health Sciences Research, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Joseph S. Reddy
- Department of Health Sciences Research, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | | | - Bradley F. Boeve
- Department of Neurology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 USA
| | - Ronald C. Petersen
- Department of Neurology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 USA
| | - David S. Knopman
- Department of Neurology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 USA
| | - Keith A. Josephs
- Department of Neurology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905 USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Björn Oskarsson
- Department of Neurology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - John W. Sheppard
- Gianforte School of Computing, Montana State University, 357 Barnard Hall, Bozeman, MT 59717 USA
| | - Yan W. Asmann
- Department of Health Sciences Research, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Rosa Rademakers
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Marka van Blitterswijk
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
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17
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Goodman LD, Prudencio M, Kramer NJ, Martinez-Ramirez LF, Srinivasan AR, Lan M, Parisi MJ, Zhu Y, Chew J, Cook CN, Berson A, Gitler AD, Petrucelli L, Bonini NM. Toxic expanded GGGGCC repeat transcription is mediated by the PAF1 complex in C9orf72-associated FTD. Nat Neurosci 2019; 22:863-874. [PMID: 31110321 PMCID: PMC6535128 DOI: 10.1038/s41593-019-0396-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 03/26/2019] [Indexed: 02/06/2023]
Abstract
An expanded GGGGCC hexanucleotide of more than 30 repeats (termed (G4C2)30+) within C9orf72 is the most prominent mutation in familial frontotemporal degeneration (FTD) and amyotrophic lateral sclerosis (ALS) (termed C9+). Through an unbiased large-scale screen of (G4C2)49-expressing Drosophila we identify the CDC73/PAF1 complex (PAF1C), a transcriptional regulator of RNA polymerase II, as a suppressor of G4C2-associated toxicity when knocked-down. Depletion of PAF1C reduces RNA and GR dipeptide production from (G4C2)30+ transgenes. Notably, in Drosophila, the PAF1C components Paf1 and Leo1 appear to be selective for the transcription of long, toxic repeat expansions, but not shorter, nontoxic expansions. In yeast, PAF1C components regulate the expression of both sense and antisense repeats. PAF1C is upregulated following (G4C2)30+ expression in flies and mice. In humans, PAF1 is also upregulated in C9+-derived cells, and its heterodimer partner, LEO1, binds C9+ repeat chromatin. In C9+ FTD, PAF1 and LEO1 are upregulated and their expression positively correlates with the expression of repeat-containing C9orf72 transcripts. These data indicate that PAF1C activity is an important factor for transcription of the long, toxic repeat in C9+ FTD.
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Affiliation(s)
- Lindsey D Goodman
- Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Nicholas J Kramer
- Neuroscience Graduate Program, Stanford University School of Medicine, Stanford, CA, USA
| | | | | | - Matthews Lan
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael J Parisi
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Yongqing Zhu
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jeannie Chew
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Casey N Cook
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Amit Berson
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Aaron D Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Nancy M Bonini
- Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA.
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18
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Nguyen L, Cleary JD, Ranum LPW. Repeat-Associated Non-ATG Translation: Molecular Mechanisms and Contribution to Neurological Disease. Annu Rev Neurosci 2019; 42:227-247. [PMID: 30909783 DOI: 10.1146/annurev-neuro-070918-050405] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Microsatellite mutations involving the expansion of tri-, tetra-, penta-, or hexanucleotide repeats cause more than 40 different neurological disorders. Although, traditionally, the position of the repeat within or outside of an open reading frame has been used to focus research on disease mechanisms involving protein loss of function, protein gain of function, or RNA gain of function, the discoveries of bidirectional transcription and repeat-associated non-ATG (RAN) have blurred these distinctions. Here we review what is known about RAN proteins in disease, the mechanisms by which they are produced, and the novel therapeutic opportunities they provide.
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Affiliation(s)
- Lien Nguyen
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610, USA;
| | - John Douglas Cleary
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610, USA;
| | - Laura P W Ranum
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610, USA;
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19
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Di Gregorio SE, Duennwald ML. ALS Yeast Models-Past Success Stories and New Opportunities. Front Mol Neurosci 2018; 11:394. [PMID: 30425620 PMCID: PMC6218427 DOI: 10.3389/fnmol.2018.00394] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 10/10/2018] [Indexed: 12/11/2022] Open
Abstract
In the past two decades, yeast models have delivered profound insights into basic mechanisms of protein misfolding and the dysfunction of key cellular pathways associated with amyotrophic lateral sclerosis (ALS). Expressing ALS-associated proteins, such as superoxide dismutase (SOD1), TAR DNA binding protein 43 (TDP-43) and Fused in sarcoma (FUS), in yeast recapitulates major hallmarks of ALS pathology, including protein aggregation, mislocalization and cellular toxicity. Results from yeast have consistently been recapitulated in other model systems and even specimens from human patients, thus providing evidence for the power and validity of ALS yeast models. Focusing on impaired ribonucleic acid (RNA) metabolism and protein misfolding and their cytotoxic consequences in ALS, we summarize exemplary discoveries that originated from work in yeast. We also propose previously unexplored experimental strategies to modernize ALS yeast models, which will help to decipher the basic pathomechanisms underlying ALS and thus, possibly contribute to finding a cure.
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Affiliation(s)
- Sonja E Di Gregorio
- Schulich School of Medicine and Dentistry, Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - Martin L Duennwald
- Schulich School of Medicine and Dentistry, Pathology and Laboratory Medicine, Western University, London, ON, Canada
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20
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Hartmann H, Hornburg D, Czuppa M, Bader J, Michaelsen M, Farny D, Arzberger T, Mann M, Meissner F, Edbauer D. Proteomics and C9orf72 neuropathology identify ribosomes as poly-GR/PR interactors driving toxicity. Life Sci Alliance 2018; 1:e201800070. [PMID: 30456350 PMCID: PMC6238541 DOI: 10.26508/lsa.201800070] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 04/27/2018] [Accepted: 04/28/2018] [Indexed: 11/25/2022] Open
Abstract
Proteomics and neuropathological validation show that aberrant poly-GR/PR proteins in C9orf72 ALS/FTD bind STAU2 and ribosomes and inhibit translation. Frontotemporal dementia and amyotrophic lateral sclerosis patients with C9orf72 mutation show cytoplasmic poly-GR and poly-PR aggregates. Short poly-(Gly-Arg) and poly-(Pro-Arg) (poly-GR/PR) repeats localizing to the nucleolus are toxic in various model systems, but no interactors have been validated in patients. Here, the neuronal interactomes of cytoplasmic GFP-(GR)149 and nucleolar (PR)175-GFP revealed overlapping RNA-binding proteins, including components of stress granules, nucleoli, and ribosomes. Overexpressing the poly-GR/PR interactors STAU1/2 and YBX1 caused cytoplasmic aggregation of poly-GR/PR in large stress granule–like structures, whereas NPM1 recruited poly-GR into the nucleolus. Poly-PR expression reduced ribosome levels and translation consistent with reduction of synaptic proteins detected by proteomics. Surprisingly, truncated GFP-(GR)53, but not GFP-(GR)149, localized to the nucleolus and reduced ribosome levels and translation similar to poly-PR, suggesting that impaired ribosome biogenesis may be driving the acute toxicity observed in vitro. In patients, only ribosomes and STAU2 co-aggregated with poly-GR/PR. Partial sequestration of ribosomes may chronically impair protein synthesis even in the absence of nucleolar localization and contribute to pathogenesis.
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Affiliation(s)
| | | | - Mareike Czuppa
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Jakob Bader
- Max Planck Institute for Biochemistry, Martinsried, Germany
| | - Meike Michaelsen
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Daniel Farny
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Thomas Arzberger
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Center for Neuropathology and Prion Research, Ludwig-Maximilians-University Munich, Munich, Germany.,Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Matthias Mann
- Max Planck Institute for Biochemistry, Martinsried, Germany.,Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Felix Meissner
- Max Planck Institute for Biochemistry, Martinsried, Germany
| | - Dieter Edbauer
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Ludwig-Maximilians-University Munich, Munich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
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