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Hwang RD, Lu Y, Tang Q, Periz G, Park G, Li X, Xiang Q, Liu Y, Zhang T, Wang J. DBT is a metabolic switch for maintenance of proteostasis under proteasomal impairment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.12.556394. [PMID: 37745492 PMCID: PMC10515868 DOI: 10.1101/2023.09.12.556394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Proteotoxic stress impairs cellular homeostasis and underlies the pathogenesis of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). The proteasomal and autophagic degradation of proteins are two major pathways for protein quality control in the cell. Here, we report a genome-wide CRISPR screen uncovering a major regulator of cytotoxicity resulting from the inhibition of the proteasome. Dihydrolipoamide branched chain transacylase E2 (DBT) was found to be a robust suppressor, the loss of which protects against proteasome inhibition-associated cell death through promoting clearance of ubiquitinated proteins. Loss of DBT altered the metabolic and energetic status of the cell and resulted in activation of autophagy in an AMP-activated protein kinase (AMPK)-dependent mechanism in the presence of proteasomal inhibition. Loss of DBT protected against proteotoxicity induced by ALS-linked mutant TDP-43 in Drosophila and mammalian neurons. DBT is upregulated in the tissues from ALS patients. These results demonstrate that DBT is a master switch in the metabolic control of protein quality control with implications in neurodegenerative diseases.
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2
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Kinger S, Jagtap YA, Kumar P, Choudhary A, Prasad A, Prajapati VK, Kumar A, Mehta G, Mishra A. Proteostasis in neurodegenerative diseases. Adv Clin Chem 2024; 121:270-333. [PMID: 38797543 DOI: 10.1016/bs.acc.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Proteostasis is essential for normal function of proteins and vital for cellular health and survival. Proteostasis encompasses all stages in the "life" of a protein, that is, from translation to functional performance and, ultimately, to degradation. Proteins need native conformations for function and in the presence of multiple types of stress, their misfolding and aggregation can occur. A coordinated network of proteins is at the core of proteostasis in cells. Among these, chaperones are required for maintaining the integrity of protein conformations by preventing misfolding and aggregation and guide those with abnormal conformation to degradation. The ubiquitin-proteasome system (UPS) and autophagy are major cellular pathways for degrading proteins. Although failure or decreased functioning of components of this network can lead to proteotoxicity and disease, like neuron degenerative diseases, underlying factors are not completely understood. Accumulating misfolded and aggregated proteins are considered major pathomechanisms of neurodegeneration. In this chapter, we have described the components of three major branches required for proteostasis-chaperones, UPS and autophagy, the mechanistic basis of their function, and their potential for protection against various neurodegenerative conditions, like Alzheimer's, Parkinson's, and Huntington's disease. The modulation of various proteostasis network proteins, like chaperones, E3 ubiquitin ligases, proteasome, and autophagy-associated proteins as therapeutic targets by small molecules as well as new and unconventional approaches, shows promise.
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Affiliation(s)
- Sumit Kinger
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan, India
| | - Yuvraj Anandrao Jagtap
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan, India
| | - Prashant Kumar
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan, India
| | - Akash Choudhary
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan, India
| | - Amit Prasad
- School of Biosciences and Bioengineering, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh, India
| | - Vijay Kumar Prajapati
- Department of Biochemistry, University of Delhi South Campus, Dhaula Kuan, New Delhi, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore, Madhya Pradesh, India
| | - Gunjan Mehta
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Telangana, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Rajasthan, India.
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3
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Uy G, Farrell LN, Faheem SF, Kinne LE, Adore MG, Im SH, Fairman R. The Effects of poly-GA and poly-PR C9orf72 Dipeptide Repeats on Sleep Patterns in Drosophila melanogaster. MICROPUBLICATION BIOLOGY 2024; 2024:10.17912/micropub.biology.000973. [PMID: 38495583 PMCID: PMC10943360 DOI: 10.17912/micropub.biology.000973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 01/31/2024] [Accepted: 03/01/2024] [Indexed: 03/19/2024]
Abstract
C9orf72 is the most common familial gene associated with amyotrophic lateral sclerosis (ALS). Dipeptide repeats (DPRs) encoded by an expanded nucleotide repeat sequence in the C9orf72 gene were found in the sleep-related neurons of patients, indicating a role of DPRs in ALS-associated sleep disruptions. Poly-GA or poly-PR DPRs were expressed in male Drosophila melanogaster to study their effect on sleep . Poly-PR expression caused sleep disruptions while poly-GA expression did not. This study validates the use of Drosophila as an in vivo model system for exploring the roles of DPRs in perturbing the underlying molecular mechanisms in sleep regulation.
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Affiliation(s)
- Genevieve Uy
- Chemistry, Haverford College, Philadelphia, Pennsylvania, United States
| | - Laura N. Farrell
- Neuroscience, Haverford College, Philadelphia, Pennsylvania, United States
| | - Syeda F. Faheem
- Biology, Haverford College, Philadelphia, Pennsylvania, United States
| | - Lauren E. Kinne
- Biology, Haverford College, Philadelphia, Pennsylvania, United States
| | - Madison G. Adore
- Biology, Haverford College, Philadelphia, Pennsylvania, United States
| | - Seol Hee Im
- Biology, Haverford College, Philadelphia, Pennsylvania, United States
| | - Robert Fairman
- Biology, Haverford College, Philadelphia, Pennsylvania, United States
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4
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Smeele PH, Cesare G, Vaccari T. ALS' Perfect Storm: C9orf72-Associated Toxic Dipeptide Repeats as Potential Multipotent Disruptors of Protein Homeostasis. Cells 2024; 13:178. [PMID: 38247869 PMCID: PMC10813877 DOI: 10.3390/cells13020178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/10/2024] [Accepted: 01/12/2024] [Indexed: 01/23/2024] Open
Abstract
Protein homeostasis is essential for neuron longevity, requiring a balanced regulation between protein synthesis and degradation. The clearance of misfolded and aggregated proteins, mediated by autophagy and the ubiquitin-proteasome systems, maintains protein homeostasis in neurons, which are post-mitotic and thus cannot use cell division to diminish the burden of misfolded proteins. When protein clearance pathways are overwhelmed or otherwise disrupted, the accumulation of misfolded or aggregated proteins can lead to the activation of ER stress and the formation of stress granules, which predominantly attempt to restore the homeostasis by suppressing global protein translation. Alterations in these processes have been widely reported among studies investigating the toxic function of dipeptide repeats (DPRs) produced by G4C2 expansion in the C9orf72 gene of patients with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). In this review, we outline the modalities of DPR-induced disruptions in protein homeostasis observed in a wide range of models of C9orf72-linked ALS/FTD. We also discuss the relative importance of each DPR for toxicity, possible synergies between DPRs, and discuss the possible functional relevance of DPR aggregation to disease pathogenesis. Finally, we highlight the interdependencies of the observed effects and reflect on the importance of feedback and feedforward mechanisms in their contribution to disease progression. A better understanding of DPR-associated disease pathogenesis discussed in this review might shed light on disease vulnerabilities that may be amenable with therapeutic interventions.
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Affiliation(s)
| | | | - Thomas Vaccari
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
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5
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Rothstein JD, Baskerville V, Rapuri S, Mehlhop E, Jafar-Nejad P, Rigo F, Bennett F, Mizielinska S, Isaacs A, Coyne AN. G 2C 4 targeting antisense oligonucleotides potently mitigate TDP-43 dysfunction in human C9orf72 ALS/FTD induced pluripotent stem cell derived neurons. Acta Neuropathol 2023; 147:1. [PMID: 38019311 PMCID: PMC10840905 DOI: 10.1007/s00401-023-02652-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/09/2023] [Accepted: 10/26/2023] [Indexed: 11/30/2023]
Abstract
The G4C2 repeat expansion in the C9orf72 gene is the most common genetic cause of Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Many studies suggest that dipeptide repeat proteins produced from this repeat are toxic, yet, the contribution of repeat RNA toxicity is under investigated and even less is known regarding the pathogenicity of antisense repeat RNA. Recently, two clinical trials targeting G4C2 (sense) repeat RNA via antisense oligonucleotide failed despite a robust decrease in sense-encoded dipeptide repeat proteins demonstrating target engagement. Here, in this brief report, we show that G2C4 antisense, but not G4C2 sense, repeat RNA is sufficient to induce TDP-43 dysfunction in induced pluripotent stem cell (iPSC) derived neurons (iPSNs). Unexpectedly, only G2C4, but not G4C2 sense strand targeting, ASOs mitigate deficits in TDP-43 function in authentic C9orf72 ALS/FTD patient iPSNs. Collectively, our data suggest that the G2C4 antisense repeat RNA may be an important therapeutic target and provide insights into a possible explanation for the recent G4C2 ASO clinical trial failure.
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Affiliation(s)
- Jeffrey D Rothstein
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Victoria Baskerville
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Sampath Rapuri
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Emma Mehlhop
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | | | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA, 92010, USA
| | | | - Sarah Mizielinska
- UK Dementia Research Institute at King's College London, London, UK
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Maurice Wohl Clinical Neuroscience Institute, King's College London, London, UK
| | - Adrian Isaacs
- UK Dementia Research Institute at UCL, London, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
- UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, London, UK
| | - Alyssa N Coyne
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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6
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Zhang Y, Nelson SCK, Viera Ortiz AP, Lee EB, Fairman R. C9orf72 proline-arginine dipeptide repeats disrupt the proteasome and perturb proteolytic activities. J Neuropathol Exp Neurol 2023; 82:901-910. [PMID: 37791472 PMCID: PMC10587997 DOI: 10.1093/jnen/nlad078] [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] [Indexed: 10/05/2023] Open
Abstract
The hexanucleotide G4C2 repeat expansion in C9orf72 is the most frequent genetic cause of familial amyotrophic lateral sclerosis (ALS). Aberrant translation of this hexanucleotide sequence leads to production of 5 dipeptide repeats (DPRs). One of these DPRs is proline-arginine (polyPR), which is found in C9orf72-expanded ALS (C9ALS) patient brain tissue and is neurotoxic across multiple model systems. PolyPR was previously reported to bind and impair proteasomes in vitro. Nevertheless, the clinical relevance of the polyPR-proteasome interaction and its functional consequences in vivo are yet to be established. Here, we aim to confirm and functionally characterize polyPR-induced impairment of proteolysis in C9ALS patient tissue and an in vivo model system. Confocal microscopy and immunofluorescence studies on both human and Drosophila melanogaster brain tissues revealed sequestration of proteasomes by polyPR into inclusion-like bodies. Co-immunoprecipitation in D. melanogaster showed that polyPR strongly binds to the proteasome. In vivo, functional evidence for proteasome impairment is further shown by the accumulation of ubiquitinated proteins along with lysosomal accumulation and hyper-acidification, which can be rescued by a small-molecule proteasomal enhancer. Together, we provide the first clinical report of polyPR-proteasome interactions and offer in vivo evidence proposing polyPR-induced proteolytic dysfunction as a pathogenic mechanism in C9ALS.
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Affiliation(s)
- Yifan Zhang
- Department of Biology, Haverford College, Haverford, Pennsylvania, USA
| | - Sophia C K Nelson
- Department of Biology, Haverford College, Haverford, Pennsylvania, USA
| | - Ashley P Viera Ortiz
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, 613A Stellar Chance Laboratories, Philadelphia, Pennsylvania, USA
| | - Edward B Lee
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, 613A Stellar Chance Laboratories, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Robert Fairman
- Department of Biology, Haverford College, Haverford, Pennsylvania, USA
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7
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Fu RH, Chen HJ, Hong SY. Interaction of the C9orf72-Amyotrophic Lateral Sclerosis-Related Proline-Arginine Dipeptide Repeat Protein with the RNA-Binding Protein NOVA1 Causes Decreased Expression of UNC13A Due to Enhanced Inclusion of Cryptic Exons, Which Is Reversed by Betulin Treatment. Cells 2023; 12:2476. [PMID: 37887320 PMCID: PMC10605128 DOI: 10.3390/cells12202476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/09/2023] [Accepted: 10/13/2023] [Indexed: 10/28/2023] Open
Abstract
C9orf72 mutations are the most common form of familial amyotrophic lateral sclerosis (C9-ALS). It causes the production of proline-arginine dipeptide repeat proteins (PR-DPRs) in motor neurons (MNs), leading to the molecular pathology characteristic of ALS. UNC13A is critical for maintaining the synaptic function of MNs. Most ALS patients have nuclear deletion of the splicing repressor TDP-43 in MNs, which causes inclusion of the cryptic exon (CE) of UNC13A mRNA, resulting in nonsense-mediated mRNA decay and reduced protein expression. Therefore, in this study, we explored the role of PR-DPR in CE inclusion of UNC13A mRNA. Our results showed that PR-DPR (PR50) induced CE inclusion and decreased the protein expression of UNC13A in human neuronal cell lines. We also identified an interaction between the RNA-binding protein NOVA1 and PR50 by yeast two-hybrid screening. NOVA1 expression is known to be reduced in patients with ALS. We found that knockdown of NOVA1 enhanced CE inclusion of UNC13A mRNA. Furthermore, the naturally occurring triterpene betulin can inhibit the interaction between NOVA1 and PR50, thus preventing CE inclusion of UNC13A mRNA and protein reduction in human neuronal cell lines. This study linked PR-DPR with CE inclusion of UNC13A mRNA and developed candidate therapeutic strategies for C9-ALS using betulin.
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Affiliation(s)
- Ru-Huei Fu
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40402, Taiwan
- Translational Medicine Research Center, China Medical University Hospital, Taichung 40447, Taiwan
- Ph.D. Program for Aging, China Medical University, Taichung 40402, Taiwan
| | - Hui-Jye Chen
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40402, Taiwan
| | - Syuan-Yu Hong
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40402, Taiwan
- Department of Medicine, School of Medicine, China Medical University, Taichung 40447, Taiwan
- Division of Pediatric Neurology, China Medical University Children’s Hospital, Taichung 40447, Taiwan
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8
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Antoniani F, Cimino M, Mediani L, Vinet J, Verde EM, Secco V, Yamoah A, Tripathi P, Aronica E, Cicardi ME, Trotti D, Sterneckert J, Goswami A, Carra S. Loss of PML nuclear bodies in familial amyotrophic lateral sclerosis-frontotemporal dementia. Cell Death Discov 2023; 9:248. [PMID: 37454169 DOI: 10.1038/s41420-023-01547-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 06/20/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD) are two neurodegenerative disorders that share genetic causes and pathogenic mechanisms. The critical genetic players of ALS and FTD are the TARDBP, FUS and C9orf72 genes, whose protein products, TDP-43, FUS and the C9orf72-dipeptide repeat proteins, accumulate in form of cytoplasmic inclusions. The majority of the studies focus on the understanding of how cells control TDP-43 and FUS aggregation in the cytoplasm, overlooking how dysfunctions occurring at the nuclear level may influence the maintenance of protein solubility outside of the nucleus. However, protein quality control (PQC) systems that maintain protein homeostasis comprise a cytoplasmic and a nuclear arm that are interconnected and share key players. It is thus conceivable that impairment of the nuclear arm of the PQC may have a negative impact on the cytoplasmic arm of the PQC, contributing to the formation of the cytoplasmic pathological inclusions. Here we focused on two stress-inducible condensates that act as transient deposition sites for misfolding-prone proteins: Promyelocytic leukemia protein (PML) nuclear bodies (PML-NBs) and cytoplasmic stress granules (SGs). Upon stress, PML-NBs compartmentalize misfolded proteins, including defective ribosomal products (DRiPs), and recruit chaperones and proteasomes to promote their nuclear clearance. SGs transiently sequester aggregation-prone RNA-binding proteins linked to ALS-FTD and mRNAs to attenuate their translation. We report that PML assembly is impaired in the human brain and spinal cord of familial C9orf72 and FUS ALS-FTD cases. We also show that defective PML-NB assembly impairs the compartmentalization of DRiPs in the nucleus, leading to their accumulation inside cytoplasmic SGs, negatively influencing SG dynamics. Although it is currently unclear what causes the decrease of PML-NBs in ALS-FTD, our data highlight the existence of a cross-talk between the cytoplasmic and nuclear PQC systems, whose alteration can contribute to SG accumulation and cytoplasmic protein aggregation in ALS-FTD.
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Affiliation(s)
- Francesco Antoniani
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Marco Cimino
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Laura Mediani
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Jonathan Vinet
- Centro Interdipartimentale Grandi Strumenti (CIGS), University of Modena and Reggio Emilia, Modena, Italy
| | - Enza M Verde
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Valentina Secco
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Alfred Yamoah
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Priyanka Tripathi
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Eleonora Aronica
- Amsterdam UMC location University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Meibergdreef 9, Amsterdam, the Netherlands
| | - Maria E Cicardi
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Davide Trotti
- Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Jared Sterneckert
- Center for Regenerative Therapies TU Dresden, Technische Universität Dresden, Dresden, Germany
- Medical Faculty Carl Gustav Carus of TU Dresden, Dresden, Germany
| | - Anand Goswami
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany.
- Department of Neurology, Center for Motor Neuron Biology and Disease, Columbia University, 10032, New York, NY, USA.
- Department of Neurology, Eleanor and Lou Gehrig ALS Center, Columbia University, 10032, New York, NY, USA.
| | - Serena Carra
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
- Medical Faculty Carl Gustav Carus of TU Dresden, Dresden, Germany.
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9
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Vanecek AS, Mojsilovic-Petrovic J, Kalb RG, Tepe JJ. Enhanced Degradation of Mutant C9ORF72-Derived Toxic Dipeptide Repeat Proteins by 20S Proteasome Activation Results in Restoration of Proteostasis and Neuroprotection. ACS Chem Neurosci 2023. [PMID: 37015082 DOI: 10.1021/acschemneuro.2c00732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023] Open
Abstract
A hexanucleotide repeat expansion (HRE) in an intron of gene C9ORF72 is the most common cause of familial amyotrophic lateral sclerosis and frontotemporal dementia. The HRE undergoes noncanonical translation (repeat-associated non-ATG translation) resulting in the production of five distinct dipeptide repeat (DPR) proteins. Arginine-rich DPR proteins have shown to be toxic to motor neurons, and recent evidence suggests this toxicity is associated with disruption of the ubiquitin-proteasome system. Here we report the ability of known 20S proteasome activator, TCH-165, to enhance the degradation of DPR proteins and overcome proteasome impairment evoked by DPR proteins. Furthermore, the 20S activator protects rodent motor neurons from DPR protein toxicity and restores proteostasis in cortical neuron cultures. This study suggests that 20S proteasome enhancers may have therapeutic efficacy in neurodegenerative diseases that display proteostasis defects.
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Affiliation(s)
- Allison S Vanecek
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Jelena Mojsilovic-Petrovic
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
| | - Robert G Kalb
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
| | - Jetze J Tepe
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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10
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Boeynaems S, Ma XR, Yeong V, Ginell GM, Chen JH, Blum JA, Nakayama L, Sanyal A, Briner A, Haver DV, Pauwels J, Ekman A, Schmidt HB, Sundararajan K, Porta L, Lasker K, Larabell C, Hayashi MAF, Kundaje A, Impens F, Obermeyer A, Holehouse AS, Gitler AD. Aberrant phase separation is a common killing strategy of positively charged peptides in biology and human disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.09.531820. [PMID: 36945394 PMCID: PMC10028949 DOI: 10.1101/2023.03.09.531820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Positively charged repeat peptides are emerging as key players in neurodegenerative diseases. These peptides can perturb diverse cellular pathways but a unifying framework for how such promiscuous toxicity arises has remained elusive. We used mass-spectrometry-based proteomics to define the protein targets of these neurotoxic peptides and found that they all share similar sequence features that drive their aberrant condensation with these positively charged peptides. We trained a machine learning algorithm to detect such sequence features and unexpectedly discovered that this mode of toxicity is not limited to human repeat expansion disorders but has evolved countless times across the tree of life in the form of cationic antimicrobial and venom peptides. We demonstrate that an excess in positive charge is necessary and sufficient for this killer activity, which we name 'polycation poisoning'. These findings reveal an ancient and conserved mechanism and inform ways to leverage its design rules for new generations of bioactive peptides.
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Affiliation(s)
- Steven Boeynaems
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030, USA
- Therapeutic Innovation Center (THINC), Baylor College of Medicine, Houston, TX 77030, USA
- Center for Alzheimer’s and Neurodegenerative Diseases (CAND), Texas Children’s Hospital, Houston, TX 77030, USA
- Dan L Duncan Comprehensive Cancer Center (DLDCCC), Baylor College of Medicine, Houston, TX 77030, USA
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - X. Rosa Ma
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Vivian Yeong
- Department of Chemical Engineering, Columbia University, New York, NY, 10027, USA
| | - Garrett M. Ginell
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
- Center for Biomolecular Condensates, Washington University in St Louis, St. Louis, MO 63130, USA
| | - Jian-Hua Chen
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California, San Francisco, CA 94143, USA
| | - Jacob A. Blum
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lisa Nakayama
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Anushka Sanyal
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Adam Briner
- Clem Jones Centre for Ageing Dementia Research (CJCADR), Queensland Brain Institute (QBI), The University of Queensland, Brisbane, QLD 4072, Australia
| | - Delphi Van Haver
- VIB-UGent Center for Medical Biotechnology, 9000 Gent, Belgium
- VIB Proteomics Core, 9000 Gent, Belgium
- Department of Biochemistry, Ghent University, 9000 Gent, Belgium
| | - Jarne Pauwels
- VIB-UGent Center for Medical Biotechnology, 9000 Gent, Belgium
- VIB Proteomics Core, 9000 Gent, Belgium
- Department of Biochemistry, Ghent University, 9000 Gent, Belgium
| | - Axel Ekman
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California, San Francisco, CA 94143, USA
| | - H. Broder Schmidt
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kousik Sundararajan
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lucas Porta
- Department of Pharmacology, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), Sao Paulo, Brazil
| | - Keren Lasker
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Carolyn Larabell
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Anatomy, University of California, San Francisco, CA 94143, USA
| | - Mirian A. F. Hayashi
- Department of Pharmacology, Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP), Sao Paulo, Brazil
| | - Anshul Kundaje
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Computer Science, Stanford University, Stanford, CA 94305, USA
| | - Francis Impens
- VIB-UGent Center for Medical Biotechnology, 9000 Gent, Belgium
- VIB Proteomics Core, 9000 Gent, Belgium
- Department of Biochemistry, Ghent University, 9000 Gent, Belgium
| | - Allie Obermeyer
- Department of Chemical Engineering, Columbia University, New York, NY, 10027, USA
| | - Alex S. Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
- Center for Biomolecular Condensates, Washington University in St Louis, St. Louis, MO 63130, USA
| | - Aaron D. Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
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11
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Shahpasand-Kroner H, Siddique I, Malik R, Linares GR, Ivanova MI, Ichida J, Weil T, Münch J, Sanchez-Garcia E, Klärner FG, Schrader T, Bitan G. Molecular Tweezers: Supramolecular Hosts with Broad-Spectrum Biological Applications. Pharmacol Rev 2023; 75:263-308. [PMID: 36549866 PMCID: PMC9976797 DOI: 10.1124/pharmrev.122.000654] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 10/14/2022] [Accepted: 10/19/2022] [Indexed: 12/24/2022] Open
Abstract
Lysine-selective molecular tweezers (MTs) are supramolecular host molecules displaying a remarkably broad spectrum of biologic activities. MTs act as inhibitors of the self-assembly and toxicity of amyloidogenic proteins using a unique mechanism. They destroy viral membranes and inhibit infection by enveloped viruses, such as HIV-1 and SARS-CoV-2, by mechanisms unrelated to their action on protein self-assembly. They also disrupt biofilm of Gram-positive bacteria. The efficacy and safety of MTs have been demonstrated in vitro, in cell culture, and in vivo, suggesting that these versatile compounds are attractive therapeutic candidates for various diseases, infections, and injuries. A lead compound called CLR01 has been shown to inhibit the aggregation of various amyloidogenic proteins, facilitate their clearance in vivo, prevent infection by multiple viruses, display potent anti-biofilm activity, and have a high safety margin in animal models. The inhibitory effect of CLR01 against amyloidogenic proteins is highly specific to abnormal self-assembly of amyloidogenic proteins with no disruption of normal mammalian biologic processes at the doses needed for inhibition. Therapeutic effects of CLR01 have been demonstrated in animal models of proteinopathies, lysosomal-storage diseases, and spinal-cord injury. Here we review the activity and mechanisms of action of these intriguing compounds and discuss future research directions. SIGNIFICANCE STATEMENT: Molecular tweezers are supramolecular host molecules with broad biological applications, including inhibition of abnormal protein aggregation, facilitation of lysosomal clearance of toxic aggregates, disruption of viral membranes, and interference of biofilm formation by Gram-positive bacteria. This review discusses the molecular and cellular mechanisms of action of the molecular tweezers, including the discovery of distinct mechanisms acting in vitro and in vivo, and the application of these compounds in multiple preclinical disease models.
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Affiliation(s)
- Hedieh Shahpasand-Kroner
- Department of Neurology, David Geffen School of Medicine (H.S.-K., I.S., R.M., G.B.), Brain Research Institute (G.B.), and Molecular Biology Institute (G.B.), University of California, Los Angeles, California; Department of Stem Cell Biology & Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (G.R.L., J.I.); Department of Neurology, University of Michigan, Ann Arbor, Michigan (M.I.I.); Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany (T.W., J.M.); and Department of Computational Biochemistry (E.S.-G.) and Faculty of Chemistry (F-G.K., T.S.), University of Duisburg-Essen, Essen, Germany
| | - Ibrar Siddique
- Department of Neurology, David Geffen School of Medicine (H.S.-K., I.S., R.M., G.B.), Brain Research Institute (G.B.), and Molecular Biology Institute (G.B.), University of California, Los Angeles, California; Department of Stem Cell Biology & Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (G.R.L., J.I.); Department of Neurology, University of Michigan, Ann Arbor, Michigan (M.I.I.); Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany (T.W., J.M.); and Department of Computational Biochemistry (E.S.-G.) and Faculty of Chemistry (F-G.K., T.S.), University of Duisburg-Essen, Essen, Germany
| | - Ravinder Malik
- Department of Neurology, David Geffen School of Medicine (H.S.-K., I.S., R.M., G.B.), Brain Research Institute (G.B.), and Molecular Biology Institute (G.B.), University of California, Los Angeles, California; Department of Stem Cell Biology & Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (G.R.L., J.I.); Department of Neurology, University of Michigan, Ann Arbor, Michigan (M.I.I.); Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany (T.W., J.M.); and Department of Computational Biochemistry (E.S.-G.) and Faculty of Chemistry (F-G.K., T.S.), University of Duisburg-Essen, Essen, Germany
| | - Gabriel R Linares
- Department of Neurology, David Geffen School of Medicine (H.S.-K., I.S., R.M., G.B.), Brain Research Institute (G.B.), and Molecular Biology Institute (G.B.), University of California, Los Angeles, California; Department of Stem Cell Biology & Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (G.R.L., J.I.); Department of Neurology, University of Michigan, Ann Arbor, Michigan (M.I.I.); Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany (T.W., J.M.); and Department of Computational Biochemistry (E.S.-G.) and Faculty of Chemistry (F-G.K., T.S.), University of Duisburg-Essen, Essen, Germany
| | - Magdalena I Ivanova
- Department of Neurology, David Geffen School of Medicine (H.S.-K., I.S., R.M., G.B.), Brain Research Institute (G.B.), and Molecular Biology Institute (G.B.), University of California, Los Angeles, California; Department of Stem Cell Biology & Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (G.R.L., J.I.); Department of Neurology, University of Michigan, Ann Arbor, Michigan (M.I.I.); Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany (T.W., J.M.); and Department of Computational Biochemistry (E.S.-G.) and Faculty of Chemistry (F-G.K., T.S.), University of Duisburg-Essen, Essen, Germany
| | - Justin Ichida
- Department of Neurology, David Geffen School of Medicine (H.S.-K., I.S., R.M., G.B.), Brain Research Institute (G.B.), and Molecular Biology Institute (G.B.), University of California, Los Angeles, California; Department of Stem Cell Biology & Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (G.R.L., J.I.); Department of Neurology, University of Michigan, Ann Arbor, Michigan (M.I.I.); Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany (T.W., J.M.); and Department of Computational Biochemistry (E.S.-G.) and Faculty of Chemistry (F-G.K., T.S.), University of Duisburg-Essen, Essen, Germany
| | - Tatjana Weil
- Department of Neurology, David Geffen School of Medicine (H.S.-K., I.S., R.M., G.B.), Brain Research Institute (G.B.), and Molecular Biology Institute (G.B.), University of California, Los Angeles, California; Department of Stem Cell Biology & Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (G.R.L., J.I.); Department of Neurology, University of Michigan, Ann Arbor, Michigan (M.I.I.); Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany (T.W., J.M.); and Department of Computational Biochemistry (E.S.-G.) and Faculty of Chemistry (F-G.K., T.S.), University of Duisburg-Essen, Essen, Germany
| | - Jan Münch
- Department of Neurology, David Geffen School of Medicine (H.S.-K., I.S., R.M., G.B.), Brain Research Institute (G.B.), and Molecular Biology Institute (G.B.), University of California, Los Angeles, California; Department of Stem Cell Biology & Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (G.R.L., J.I.); Department of Neurology, University of Michigan, Ann Arbor, Michigan (M.I.I.); Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany (T.W., J.M.); and Department of Computational Biochemistry (E.S.-G.) and Faculty of Chemistry (F-G.K., T.S.), University of Duisburg-Essen, Essen, Germany
| | - Elsa Sanchez-Garcia
- Department of Neurology, David Geffen School of Medicine (H.S.-K., I.S., R.M., G.B.), Brain Research Institute (G.B.), and Molecular Biology Institute (G.B.), University of California, Los Angeles, California; Department of Stem Cell Biology & Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (G.R.L., J.I.); Department of Neurology, University of Michigan, Ann Arbor, Michigan (M.I.I.); Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany (T.W., J.M.); and Department of Computational Biochemistry (E.S.-G.) and Faculty of Chemistry (F-G.K., T.S.), University of Duisburg-Essen, Essen, Germany
| | - Frank-Gerrit Klärner
- Department of Neurology, David Geffen School of Medicine (H.S.-K., I.S., R.M., G.B.), Brain Research Institute (G.B.), and Molecular Biology Institute (G.B.), University of California, Los Angeles, California; Department of Stem Cell Biology & Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (G.R.L., J.I.); Department of Neurology, University of Michigan, Ann Arbor, Michigan (M.I.I.); Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany (T.W., J.M.); and Department of Computational Biochemistry (E.S.-G.) and Faculty of Chemistry (F-G.K., T.S.), University of Duisburg-Essen, Essen, Germany
| | - Thomas Schrader
- Department of Neurology, David Geffen School of Medicine (H.S.-K., I.S., R.M., G.B.), Brain Research Institute (G.B.), and Molecular Biology Institute (G.B.), University of California, Los Angeles, California; Department of Stem Cell Biology & Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (G.R.L., J.I.); Department of Neurology, University of Michigan, Ann Arbor, Michigan (M.I.I.); Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany (T.W., J.M.); and Department of Computational Biochemistry (E.S.-G.) and Faculty of Chemistry (F-G.K., T.S.), University of Duisburg-Essen, Essen, Germany
| | - Gal Bitan
- Department of Neurology, David Geffen School of Medicine (H.S.-K., I.S., R.M., G.B.), Brain Research Institute (G.B.), and Molecular Biology Institute (G.B.), University of California, Los Angeles, California; Department of Stem Cell Biology & Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (G.R.L., J.I.); Department of Neurology, University of Michigan, Ann Arbor, Michigan (M.I.I.); Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany (T.W., J.M.); and Department of Computational Biochemistry (E.S.-G.) and Faculty of Chemistry (F-G.K., T.S.), University of Duisburg-Essen, Essen, Germany
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12
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Crosstalk between Biomolecular Condensates and Proteostasis. Cells 2022; 11:cells11152415. [PMID: 35954258 PMCID: PMC9368065 DOI: 10.3390/cells11152415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 12/23/2022] Open
Abstract
Proper homeostasis of the proteome, referred to as proteostasis, is maintained by chaperone-dependent refolding of misfolded proteins and by protein degradation via the ubiquitin-proteasome system and the autophagic machinery. This review will discuss a crosstalk between biomolecular condensates and proteostasis, whereby the crowding of proteostasis factors into macromolecular assemblies is often established by phase separation of membraneless biomolecular condensates. Specifically, ubiquitin and other posttranslational modifications come into play as agents of phase separation, essential for the formation of condensates and for ubiquitin-proteasome system activity. Furthermore, an intriguing connection associates malfunction of the same pathways to the accumulation of misfolded and ubiquitinated proteins in aberrant condensates, the formation of protein aggregates, and finally, to the pathogenesis of neurodegenerative diseases. The crosstalk between biomolecular condensates and proteostasis is an emerging theme in cellular and disease biology and further studies will focus on delineating specific molecular pathways involved in the pathogenesis of amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases.
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Neurons undergo pathogenic metabolic reprogramming in models of familial ALS. Mol Metab 2022; 60:101468. [PMID: 35248787 PMCID: PMC8958550 DOI: 10.1016/j.molmet.2022.101468] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 02/25/2022] [Accepted: 02/25/2022] [Indexed: 11/21/2022] Open
Abstract
Objectives Methods Results Conclusions Our work is the first to perform a comprehensive and quantitative analysis of intermediary metabolism in neurons in the setting of fALS causing gene products. Because the cardinal feature of ALS is death of motor neurons, these new studies are directly relevant to the pathogenesis of ALS. Our functional interrogations begin to unpack how metabolic re-wiring is induced by fALS genes and it will be very interesting, in the future, to gain insight in amino acid fueling of the TCA cycle. We suspect pleiotropic effects of amino acid fueling, and this may lead to very targeted therapeutic interventions.
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14
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Chen C, Yamanaka Y, Ueda K, Li P, Miyagi T, Harada Y, Tezuka S, Narumi S, Sugimoto M, Kuroda M, Hayamizu Y, Kanekura K. Phase separation and toxicity of C9orf72 poly(PR) depends on alternate distribution of arginine. J Cell Biol 2021; 220:212626. [PMID: 34499080 PMCID: PMC8438627 DOI: 10.1083/jcb.202103160] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 08/05/2021] [Accepted: 08/19/2021] [Indexed: 12/15/2022] Open
Abstract
Arg (R)-rich dipeptide repeat proteins (DPRs; poly(PR): Pro-Arg and poly(GR): Gly-Arg), encoded by a hexanucleotide expansion in the C9ORF72 gene, induce neurodegeneration in amyotrophic lateral sclerosis (ALS). Although R-rich DPRs undergo liquid-liquid phase separation (LLPS), which affects multiple biological processes, mechanisms underlying LLPS of DPRs remain elusive. Here, using in silico, in vitro, and in cellulo methods, we determined that the distribution of charged Arg residues regulates the complex coacervation with anionic peptides and nucleic acids. Proteomic analyses revealed that alternate Arg distribution in poly(PR) facilitates entrapment of proteins with acidic motifs via LLPS. Transcription, translation, and diffusion of nucleolar nucleophosmin (NPM1) were impaired by poly(PR) with an alternate charge distribution but not by poly(PR) variants with a consecutive charge distribution. We propose that the pathogenicity of R-rich DPRs is mediated by disturbance of proteins through entrapment in the phase-separated droplets via sequence-controlled multivalent protein-protein interactions.
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Affiliation(s)
- Chen Chen
- Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Yoshiaki Yamanaka
- Department of Molecular Pathology, Tokyo Medical University, Tokyo, Japan
| | - Koji Ueda
- Cancer Proteomics Group, Cancer Precision Medicine Center, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Peiying Li
- Center for Biosystems Dynamics Research, RIKEN, Kanagawa, Japan
| | - Tamami Miyagi
- Department of Molecular Pathology, Tokyo Medical University, Tokyo, Japan
| | - Yuichiro Harada
- Department of Molecular Pathology, Tokyo Medical University, Tokyo, Japan
| | - Sayaka Tezuka
- Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Satoshi Narumi
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Masahiro Sugimoto
- Research and Development Center for Minimally Invasive Therapies, Tokyo Medical University, Tokyo, Japan
| | - Masahiko Kuroda
- Department of Molecular Pathology, Tokyo Medical University, Tokyo, Japan
| | - Yuhei Hayamizu
- Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, Tokyo, Japan
| | - Kohsuke Kanekura
- Department of Molecular Pathology, Tokyo Medical University, Tokyo, Japan
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15
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Torres P, Cabral-Miranda F, Gonzalez-Teuber V, Hetz C. Proteostasis deregulation as a driver of C9ORF72 pathogenesis. J Neurochem 2021; 159:941-957. [PMID: 34679204 DOI: 10.1111/jnc.15529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 10/16/2021] [Accepted: 10/18/2021] [Indexed: 12/21/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are two related neurodegenerative disorders that display overlapping features. The hexanucleotide repeat expansion GGGGCC (G4 C2 ) in C9ORF72 gene has been causally linked to both ALS and FTD emergence, thus opening a novel potential therapeutic target for disease intervention. The main driver of C9ORF72 pathology is the disruption of distinct cellular processes involved in the function of the proteostasis network. Here we discuss main findings relating to the induction of neurodegeneration by C9ORF72 mutation and proteostasis deregulation, highlighting the role of the endoplasmic reticulum stress, nuclear transport, and autophagy in the disease process. We further discuss possible points of intervention to target proteostasis mediators to treat C9ORF72-linked ALS/FTD.
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Affiliation(s)
- Paulina Torres
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile.,FONDAP Center for Geroscience, Brain Health, and Metabolism (GERO), Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Science, University of Chile, Santiago, Chile
| | - Felipe Cabral-Miranda
- Instituto de Ciências Biomédicas, Universidade do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Vicente Gonzalez-Teuber
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile.,FONDAP Center for Geroscience, Brain Health, and Metabolism (GERO), Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Science, University of Chile, Santiago, Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile.,FONDAP Center for Geroscience, Brain Health, and Metabolism (GERO), Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Science, University of Chile, Santiago, Chile.,Buck Institute for Research on Aging, Novato, California, USA
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16
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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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17
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Semmelink MFW, Steen A, Veenhoff LM. Measuring and Interpreting Nuclear Transport in Neurodegenerative Disease-The Example of C9orf72 ALS. Int J Mol Sci 2021; 22:9217. [PMID: 34502125 PMCID: PMC8431710 DOI: 10.3390/ijms22179217] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/13/2021] [Accepted: 08/18/2021] [Indexed: 11/25/2022] Open
Abstract
Transport from and into the nucleus is essential to all eukaryotic life and occurs through the nuclear pore complex (NPC). There are a multitude of data supporting a role for nuclear transport in neurodegenerative diseases, but actual transport assays in disease models have provided diverse outcomes. In this review, we summarize how nuclear transport works, which transport assays are available, and what matters complicate the interpretation of their results. Taking a specific type of ALS caused by mutations in C9orf72 as an example, we illustrate these complications, and discuss how the current data do not firmly answer whether the kinetics of nucleocytoplasmic transport are altered. Answering this open question has far-reaching implications, because a positive answer would imply that widespread mislocalization of proteins occurs, far beyond the reported mislocalization of transport reporters, and specific proteins such as FUS, or TDP43, and thus presents a challenge for future research.
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Affiliation(s)
| | | | - Liesbeth M. Veenhoff
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands; (M.F.W.S.); (A.S.)
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18
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Leskelä S, Hoffmann D, Rostalski H, Huber N, Wittrahm R, Hartikainen P, Korhonen V, Leinonen V, Hiltunen M, Solje E, Remes AM, Haapasalo A. FTLD Patient-Derived Fibroblasts Show Defective Mitochondrial Function and Accumulation of p62. Mol Neurobiol 2021; 58:5438-5458. [PMID: 34328616 PMCID: PMC8599259 DOI: 10.1007/s12035-021-02475-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/25/2021] [Indexed: 11/25/2022]
Abstract
Frontotemporal lobar degeneration (FTLD) is a clinically, genetically, and neuropathologically heterogeneous group of neurodegenerative syndromes, leading to progressive cognitive dysfunction and frontal and temporal atrophy. C9orf72 hexanucleotide repeat expansion (C9-HRE) is the most common genetic cause of FTLD, but pathogenic mechanisms underlying FTLD are not fully understood. Here, we compared cellular features and functional properties, especially related to protein degradation pathways and mitochondrial function, of FTLD patient–derived skin fibroblasts from C9-HRE carriers and non-carriers and healthy donors. Fibroblasts from C9-HRE carriers were found to produce RNA foci, but no dipeptide repeat proteins, and they showed unchanged levels of C9orf72 mRNA transcripts. The main protein degradation pathways, the ubiquitin–proteasome system and autophagy, did not show alterations between the fibroblasts from C9-HRE-carrying and non-carrying FTLD patients and compared to healthy controls. An increase in the number and size of p62-positive puncta was evident in fibroblasts from both C9-HRE carriers and non-carriers. In addition, several parameters of mitochondrial function, namely, basal and maximal respiration and respiration linked to ATP production, were significantly reduced in the FTLD patient–derived fibroblasts from both C9-HRE carriers and non-carriers. Our findings suggest that FTLD patient–derived fibroblasts, regardless of whether they carry the C9-HRE expansion, show unchanged proteasomal and autophagic function, but significantly impaired mitochondrial function and increased accumulation of p62 when compared to control fibroblasts. These findings suggest the possibility of utilizing FTLD patient–derived fibroblasts as a platform for biomarker discovery and testing of drugs targeted to specific cellular functions, such as mitochondrial respiration.
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Affiliation(s)
- Stina Leskelä
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, 70211, Kuopio, Finland
| | - Dorit Hoffmann
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, 70211, Kuopio, Finland
| | - Hannah Rostalski
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, 70211, Kuopio, Finland
| | - Nadine Huber
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, 70211, Kuopio, Finland
| | - Rebekka Wittrahm
- Institute of Biomedicine, University of Eastern Finland, Yliopistonranta 1E, 70211, Kuopio, Finland
| | - Päivi Hartikainen
- Neuro Center, Neurology, Kuopio University Hospital, 70029, Kuopio, Finland
| | - Ville Korhonen
- Neuro Center, Neurosurgery, Kuopio University Hospital, 70029, Kuopio, Finland
- Institute of Clinical Medicine - Neurosurgery, University of Eastern Finland, Yliopistonranta 1C, 70211, Kuopio, Finland
| | - Ville Leinonen
- Neuro Center, Neurosurgery, Kuopio University Hospital, 70029, Kuopio, Finland
- Institute of Clinical Medicine - Neurosurgery, University of Eastern Finland, Yliopistonranta 1C, 70211, Kuopio, Finland
| | - Mikko Hiltunen
- Institute of Biomedicine, University of Eastern Finland, Yliopistonranta 1E, 70211, Kuopio, Finland
| | - Eino Solje
- Neuro Center, Neurology, Kuopio University Hospital, 70029, Kuopio, Finland
- Institute of Clinical Medicine - Neurology, University of Eastern Finland, Yliopistonranta 1C, 70211, Kuopio, Finland
| | - Anne M Remes
- Unit of Clinical Neuroscience, Neurology, University of Oulu, P.O. Box 8000, 90014, Oulu, Finland
- MRC Oulu, Oulu University Hospital, P.O. Box 8000, 90014, Oulu, Finland
| | - Annakaisa Haapasalo
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Neulaniementie 2, 70211, Kuopio, Finland.
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19
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Pikatza-Menoio O, Elicegui A, Bengoetxea X, Naldaiz-Gastesi N, López de Munain A, Gerenu G, Gil-Bea FJ, Alonso-Martín S. The Skeletal Muscle Emerges as a New Disease Target in Amyotrophic Lateral Sclerosis. J Pers Med 2021; 11:671. [PMID: 34357138 PMCID: PMC8307751 DOI: 10.3390/jpm11070671] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/09/2021] [Accepted: 07/14/2021] [Indexed: 01/02/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder that leads to progressive degeneration of motor neurons (MNs) and severe muscle atrophy without effective treatment. Most research on ALS has been focused on the study of MNs and supporting cells of the central nervous system. Strikingly, the recent observations of pathological changes in muscle occurring before disease onset and independent from MN degeneration have bolstered the interest for the study of muscle tissue as a potential target for delivery of therapies for ALS. Skeletal muscle has just been described as a tissue with an important secretory function that is toxic to MNs in the context of ALS. Moreover, a fine-tuning balance between biosynthetic and atrophic pathways is necessary to induce myogenesis for muscle tissue repair. Compromising this response due to primary metabolic abnormalities in the muscle could trigger defective muscle regeneration and neuromuscular junction restoration, with deleterious consequences for MNs and thereby hastening the development of ALS. However, it remains puzzling how backward signaling from the muscle could impinge on MN death. This review provides a comprehensive analysis on the current state-of-the-art of the role of the skeletal muscle in ALS, highlighting its contribution to the neurodegeneration in ALS through backward-signaling processes as a newly uncovered mechanism for a peripheral etiopathogenesis of the disease.
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Affiliation(s)
- Oihane Pikatza-Menoio
- Neuromuscular Diseases Group, Neurosciences Area, Biodonostia Health Research Institute, 20014 Donostia/San Sebastián, Spain; (O.P.-M.); (A.E.); (X.B.); (N.N.-G.); (A.L.d.M.); (G.G.); (F.J.G.-B.)
- CIBERNED, Carlos III Institute, Spanish Ministry of Economy & Competitiveness, 28031 Madrid, Spain
| | - Amaia Elicegui
- Neuromuscular Diseases Group, Neurosciences Area, Biodonostia Health Research Institute, 20014 Donostia/San Sebastián, Spain; (O.P.-M.); (A.E.); (X.B.); (N.N.-G.); (A.L.d.M.); (G.G.); (F.J.G.-B.)
- CIBERNED, Carlos III Institute, Spanish Ministry of Economy & Competitiveness, 28031 Madrid, Spain
| | - Xabier Bengoetxea
- Neuromuscular Diseases Group, Neurosciences Area, Biodonostia Health Research Institute, 20014 Donostia/San Sebastián, Spain; (O.P.-M.); (A.E.); (X.B.); (N.N.-G.); (A.L.d.M.); (G.G.); (F.J.G.-B.)
| | - Neia Naldaiz-Gastesi
- Neuromuscular Diseases Group, Neurosciences Area, Biodonostia Health Research Institute, 20014 Donostia/San Sebastián, Spain; (O.P.-M.); (A.E.); (X.B.); (N.N.-G.); (A.L.d.M.); (G.G.); (F.J.G.-B.)
- CIBERNED, Carlos III Institute, Spanish Ministry of Economy & Competitiveness, 28031 Madrid, Spain
| | - Adolfo López de Munain
- Neuromuscular Diseases Group, Neurosciences Area, Biodonostia Health Research Institute, 20014 Donostia/San Sebastián, Spain; (O.P.-M.); (A.E.); (X.B.); (N.N.-G.); (A.L.d.M.); (G.G.); (F.J.G.-B.)
- CIBERNED, Carlos III Institute, Spanish Ministry of Economy & Competitiveness, 28031 Madrid, Spain
- Department of Neurology, Donostialdea Integrated Health Organization, Osakidetza Basque Health Service, 20014 Donostia/San Sebastián, Spain
- Department of Neurosciences, Faculty of Medicine and Nursery, University of the Basque Country UPV-EHU, 20014 Donostia/San Sebastián, Spain
| | - Gorka Gerenu
- Neuromuscular Diseases Group, Neurosciences Area, Biodonostia Health Research Institute, 20014 Donostia/San Sebastián, Spain; (O.P.-M.); (A.E.); (X.B.); (N.N.-G.); (A.L.d.M.); (G.G.); (F.J.G.-B.)
- CIBERNED, Carlos III Institute, Spanish Ministry of Economy & Competitiveness, 28031 Madrid, Spain
- Department of Physiology, University of the Basque Country UPV-EHU, 48940 Leioa, Spain
| | - Francisco Javier Gil-Bea
- Neuromuscular Diseases Group, Neurosciences Area, Biodonostia Health Research Institute, 20014 Donostia/San Sebastián, Spain; (O.P.-M.); (A.E.); (X.B.); (N.N.-G.); (A.L.d.M.); (G.G.); (F.J.G.-B.)
- CIBERNED, Carlos III Institute, Spanish Ministry of Economy & Competitiveness, 28031 Madrid, Spain
| | - Sonia Alonso-Martín
- Neuromuscular Diseases Group, Neurosciences Area, Biodonostia Health Research Institute, 20014 Donostia/San Sebastián, Spain; (O.P.-M.); (A.E.); (X.B.); (N.N.-G.); (A.L.d.M.); (G.G.); (F.J.G.-B.)
- CIBERNED, Carlos III Institute, Spanish Ministry of Economy & Competitiveness, 28031 Madrid, Spain
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20
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Wysocka A, Palasz E, Steczkowska M, Niewiadomska G. Dangerous Liaisons: Tau Interaction with Muscarinic Receptors. Curr Alzheimer Res 2021; 17:224-237. [PMID: 32329686 PMCID: PMC7509759 DOI: 10.2174/1567205017666200424134311] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 02/05/2020] [Accepted: 03/25/2020] [Indexed: 11/22/2022]
Abstract
The molecular processes underlying neurodegenerative diseases (such as Alzheimer's Disease - AD) remain poorly understood. There is also an imperative need for disease-modifying therapies in AD since the present treatments, acetylcholinesterase inhibitors and NMDA antagonists, do not halt its progression. AD and other dementias present unique pathological features such as that of microtubule associated protein tau metabolic regulation. Tau has numerous binding partners, including signaling molecules, cytoskeletal elements and lipids, which suggests that it is a multifunctional protein. AD has also been associated with severe loss of cholinergic markers in the brain and such loss may be due to the toxic interaction of tau with cholinergic muscarinic receptors. By using specific antagonists of muscarinic receptors it was found in vitro that extracellular tau binds to M1 and M3 receptors and which the increase of intracellular calcium found in neuronal cells upon tau-binding. However, so far, the significance of tau signaling through muscarinic receptor in vivo in tauopathic models remains uncertain. The data reviewed in the present paper highlight the significant effect of M1 receptor/tau interaction in exacerbating tauopathy related pathological features and suggest that selective M1 agonists may serve as a prototype for future therapeutic development toward modification of currently intractable neurodegenerative diseases, such as tauopathies.
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Affiliation(s)
- Adrianna Wysocka
- Neurobiology Center, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Ewelina Palasz
- Department of Applied Physiology, Mossakowski Medical Research Center, 02-093 Warsaw, Poland
| | - Marta Steczkowska
- Department of Applied Physiology, Mossakowski Medical Research Center, 02-093 Warsaw, Poland
| | - Grazyna Niewiadomska
- Neurobiology Center, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
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21
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Expression of C9orf72 hexanucleotide repeat expansion leads to formation of RNA foci and dipeptide repeat proteins but does not influence autophagy or proteasomal function in neuronal cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119021. [PMID: 33775797 DOI: 10.1016/j.bbamcr.2021.119021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 03/06/2021] [Accepted: 03/22/2021] [Indexed: 12/22/2022]
Abstract
C9orf72 hexanucleotide repeat expansion (HRE) is the major genetic cause underpinning frontotemporal lobar degeneration (FLTD) and amyotrophic lateral sclerosis (ALS). C9orf72 HRE-associated pathogenesis involves both loss-of-function, through reduced C9orf72 levels, and gain-of-function mechanisms, including formation of RNA foci and generation of dipeptide repeat (DPR) proteins. In addition, dysfunctional protein degradation pathways, i.e. autophagy and ubiquitin-proteasome system (UPS), are suggested. Our aim was to study the gain-of-function mechanisms in the context of the function of protein degradation pathways as well as the regulation of the DPR proteins through these pathways. To this end, we expressed the pathological HRE in neuronal N2a cells and mouse primary cortical neurons. Protein degradation pathways were modulated to induce or block autophagy or to inhibit UPS. In addition, proteasomal activity was assessed. The C9orf72 HRE-expressing N2a cells and neurons were confirmed to produce RNA foci and DPR proteins, predominantly the Poly-GP proteins. However, the presence of these pathological hallmarks did not result in alterations in autophagy or proteasomal activity in either of the studied cell types. In N2a cells, Poly-GP proteins appeared in soluble forms and Lactacystin-mediated UPS inhibition increased their levels, indicating proteasomal regulation. Similar effects were not observed in cortical neurons, where the Poly-GP proteins formed also higher molecular weight forms. These results suggest a cell type-specific morphology and regulation of the DPR proteins. Further studies in other model systems may shed additional light onto the effects of the C9orf72 HRE on cellular protein degradation pathways and the regulation of the DPR protein levels.
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22
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Kim JH, Lee J, Choi WH, Park S, Park SH, Lee JH, Lim SM, Mun JY, Cho HS, Han D, Suh YH, Lee MJ. CHIP-mediated hyperubiquitylation of tau promotes its self-assembly into the insoluble tau filaments. Chem Sci 2021; 12:5599-5610. [PMID: 34168795 PMCID: PMC8179656 DOI: 10.1039/d1sc00586c] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/05/2021] [Indexed: 01/08/2023] Open
Abstract
The tau protein is a highly soluble and natively unfolded protein. Under pathological conditions, tau undergoes multiple post-translational modifications (PTMs) and conformational changes to form insoluble filaments, which are the proteinaceous signatures of tauopathies. To dissect the crosstalk among tau PTMs during the aggregation process, we phosphorylated and ubiquitylated recombinant tau in vitro using GSK3β and CHIP, respectively. The resulting phospho-ub-tau contained conventional polyubiquitin chains with lysine 48 linkages, sufficient for proteasomal degradation, whereas unphosphorylated ub-tau species retained only one-three ubiquitin moieties. Mass-spectrometric analysis of in vitro reconstituted phospho-ub-tau revealed seven additional ubiquitylation sites, some of which are known to stabilize tau protofilament stacking in the human brain with tauopathy. When the ubiquitylation reaction was prolonged, phospho-ub-tau transformed into insoluble hyperubiquitylated tau species featuring fibrillar morphology and in vitro seeding activity. We developed a small-molecule inhibitor of CHIP through biophysical screening; this effectively suppressed tau ubiquitylation in vitro and delayed its aggregation in cultured cells including primary cultured neurons. Our biochemical findings point to a "multiple-hit model," where sequential events of tau phosphorylation and hyperubiquitylation function as a key driver of the fibrillization process, thus indicating that targeting tau ubiquitylation may be an effective strategy to alleviate the course of tauopathies.
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Affiliation(s)
- Ji Hyeon Kim
- Department of Biomedical Sciences, Seoul National University Graduate School Seoul 03080 Korea +82 2-744-4534 +82 2-740-8254
| | - Jeeyoung Lee
- Department of Biomedical Sciences, Seoul National University Graduate School Seoul 03080 Korea +82 2-744-4534 +82 2-740-8254
| | - Won Hoon Choi
- Department of Biomedical Sciences, Seoul National University Graduate School Seoul 03080 Korea +82 2-744-4534 +82 2-740-8254
| | - Seoyoung Park
- Department of Biochemistry & Molecular Biology, Neuroscience Research Institute, Seoul National University College of Medicine Seoul 03080 Korea
| | - Seo Hyeong Park
- Department of Biomedical Sciences, Seoul National University Graduate School Seoul 03080 Korea +82 2-744-4534 +82 2-740-8254
| | - Jung Hoon Lee
- Department of Biochemistry & Molecular Biology, Neuroscience Research Institute, Seoul National University College of Medicine Seoul 03080 Korea
| | - Sang Min Lim
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology Seoul 02792 Korea
| | - Ji Young Mun
- Neural Circuit Research Group, Korea Brain Research Institute Daegu 41062 Korea
| | - Hyun-Soo Cho
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University Seoul 03722 Korea
| | - Dohyun Han
- Proteomics Core Facility, Biomedical Research Institute, Seoul National University Hospital Seoul 03080 Korea
| | - Young Ho Suh
- Department of Biomedical Sciences, Seoul National University Graduate School Seoul 03080 Korea +82 2-744-4534 +82 2-740-8254
- Department of Biochemistry & Molecular Biology, Neuroscience Research Institute, Seoul National University College of Medicine Seoul 03080 Korea
| | - Min Jae Lee
- Department of Biomedical Sciences, Seoul National University Graduate School Seoul 03080 Korea +82 2-744-4534 +82 2-740-8254
- Department of Biochemistry & Molecular Biology, Neuroscience Research Institute, Seoul National University College of Medicine Seoul 03080 Korea
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Mechanisms of repeat-associated non-AUG translation in neurological microsatellite expansion disorders. Biochem Soc Trans 2021; 49:775-792. [PMID: 33729487 PMCID: PMC8106499 DOI: 10.1042/bst20200690] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/20/2021] [Accepted: 02/23/2021] [Indexed: 02/08/2023]
Abstract
Repeat-associated non-AUG (RAN) translation was discovered in 2011 in spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1). This non-canonical form of translation occurs in all reading frames from both coding and non-coding regions of sense and antisense transcripts carrying expansions of trinucleotide to hexanucleotide repeat sequences. RAN translation has since been reported in 7 of the 53 known microsatellite expansion disorders which mainly present with neurodegenerative features. RAN translation leads to the biosynthesis of low-complexity polymeric repeat proteins with aggregating and cytotoxic properties. However, the molecular mechanisms and protein factors involved in assembling functional ribosomes in absence of canonical AUG start codons remain poorly characterised while secondary repeat RNA structures play key roles in initiating RAN translation. Here, we briefly review the repeat expansion disorders, their complex pathogenesis and the mechanisms of physiological translation initiation together with the known factors involved in RAN translation. Finally, we discuss research challenges surrounding the understanding of pathogenesis and future directions that may provide opportunities for the development of novel therapeutic approaches for this group of incurable neurodegenerative diseases.
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24
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What Can Machine Learning Approaches in Genomics Tell Us about the Molecular Basis of Amyotrophic Lateral Sclerosis? J Pers Med 2020; 10:jpm10040247. [PMID: 33256133 PMCID: PMC7712791 DOI: 10.3390/jpm10040247] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/21/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is the most common late-onset motor neuron disorder, but our current knowledge of the molecular mechanisms and pathways underlying this disease remain elusive. This review (1) systematically identifies machine learning studies aimed at the understanding of the genetic architecture of ALS, (2) outlines the main challenges faced and compares the different approaches that have been used to confront them, and (3) compares the experimental designs and results produced by those approaches and describes their reproducibility in terms of biological results and the performances of the machine learning models. The majority of the collected studies incorporated prior knowledge of ALS into their feature selection approaches, and trained their machine learning models using genomic data combined with other types of mined knowledge including functional associations, protein-protein interactions, disease/tissue-specific information, epigenetic data, and known ALS phenotype-genotype associations. The importance of incorporating gene-gene interactions and cis-regulatory elements into the experimental design of future ALS machine learning studies is highlighted. Lastly, it is suggested that future advances in the genomic and machine learning fields will bring about a better understanding of ALS genetic architecture, and enable improved personalized approaches to this and other devastating and complex diseases.
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Rostalski H, Hietanen T, Leskelä S, Behánová A, Abdollahzadeh A, Wittrahm R, Mäkinen P, Huber N, Hoffmann D, Solje E, Remes AM, Natunen T, Takalo M, Tohka J, Hiltunen M, Haapasalo A. BV-2 Microglial Cells Overexpressing C9orf72 Hexanucleotide Repeat Expansion Produce DPR Proteins and Show Normal Functionality but No RNA Foci. Front Neurol 2020; 11:550140. [PMID: 33123074 PMCID: PMC7573144 DOI: 10.3389/fneur.2020.550140] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022] Open
Abstract
Hexanucleotide repeat expansion (HRE) in the chromosome 9 open-reading frame 72 (C9orf72) gene is the most common genetic cause underpinning frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). It leads to the accumulation of toxic RNA foci and various dipeptide repeat (DPR) proteins into cells. These C9orf72 HRE-specific hallmarks are abundant in neurons. So far, the role of microglia, the immune cells of the brain, in C9orf72 HRE-associated FTLD/ALS is unclear. In this study, we overexpressed C9orf72 HRE of a pathological length in the BV-2 microglial cell line and used biochemical methods and fluorescence imaging to investigate its effects on their phenotype, viability, and functionality. We found that BV-2 cells expressing the C9orf72 HRE presented strong expression of specific DPR proteins but no sense RNA foci. Transiently increased levels of cytoplasmic TAR DNA-binding protein 43 (TDP-43), slightly altered levels of p62 and lysosome-associated membrane protein (LAMP) 2A, and reduced levels of polyubiquitinylated proteins, but no signs of cell death were detected in HRE overexpressing cells. Overexpression of the C9orf72 HRE did not affect BV-2 cell phagocytic activity or response to an inflammatory stimulus, nor did it shift their RNA profile toward disease-associated microglia. These findings suggest that DPR proteins do not affect microglial cell viability or functionality in BV-2 cells. However, additional studies in other models are required to further elucidate the role of C9orf72 HRE in microglia.
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Affiliation(s)
- Hannah Rostalski
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Tomi Hietanen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Stina Leskelä
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Andrea Behánová
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Ali Abdollahzadeh
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Rebekka Wittrahm
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Petra Mäkinen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Nadine Huber
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Dorit Hoffmann
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Eino Solje
- Institute of Clinical Medicine-Neurology, University of Eastern Finland, Kuopio, Finland.,Neuro Center, Neurology, Kuopio University Hospital, Kuopio, Finland
| | - Anne M Remes
- Unit of Clinical Neuroscience, Neurology, University of Oulu, Oulu, Finland.,Medical Research Center (MRC) Oulu, Oulu University Hospital, Oulu, Finland
| | - Teemu Natunen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Mari Takalo
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Jussi Tohka
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Mikko Hiltunen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Annakaisa Haapasalo
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
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26
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Le Gall L, Anakor E, Connolly O, Vijayakumar UG, Duddy WJ, Duguez S. Molecular and Cellular Mechanisms Affected in ALS. J Pers Med 2020; 10:E101. [PMID: 32854276 PMCID: PMC7564998 DOI: 10.3390/jpm10030101] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/17/2020] [Accepted: 08/22/2020] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a terminal late-onset condition characterized by the loss of upper and lower motor neurons. Mutations in more than 30 genes are associated to the disease, but these explain only ~20% of cases. The molecular functions of these genes implicate a wide range of cellular processes in ALS pathology, a cohesive understanding of which may provide clues to common molecular mechanisms across both familial (inherited) and sporadic cases and could be key to the development of effective therapeutic approaches. Here, the different pathways that have been investigated in ALS are summarized, discussing in detail: mitochondrial dysfunction, oxidative stress, axonal transport dysregulation, glutamate excitotoxicity, endosomal and vesicular transport impairment, impaired protein homeostasis, and aberrant RNA metabolism. This review considers the mechanistic roles of ALS-associated genes in pathology, viewed through the prism of shared molecular pathways.
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Affiliation(s)
- Laura Le Gall
- Northern Ireland Center for Stratified/Personalised Medicine, Biomedical Sciences Research Institute, Ulster University, Derry-Londonderry BT47, UK; (L.L.G.); (E.A.); (O.C.); (U.G.V.); (W.J.D.)
- NIHR Biomedical Research Centre, University College London, Great Ormond Street Institute of Child Health and Great Ormond Street Hospital NHS Trust, London WC1N 1EH, UK
| | - Ekene Anakor
- Northern Ireland Center for Stratified/Personalised Medicine, Biomedical Sciences Research Institute, Ulster University, Derry-Londonderry BT47, UK; (L.L.G.); (E.A.); (O.C.); (U.G.V.); (W.J.D.)
| | - Owen Connolly
- Northern Ireland Center for Stratified/Personalised Medicine, Biomedical Sciences Research Institute, Ulster University, Derry-Londonderry BT47, UK; (L.L.G.); (E.A.); (O.C.); (U.G.V.); (W.J.D.)
| | - Udaya Geetha Vijayakumar
- Northern Ireland Center for Stratified/Personalised Medicine, Biomedical Sciences Research Institute, Ulster University, Derry-Londonderry BT47, UK; (L.L.G.); (E.A.); (O.C.); (U.G.V.); (W.J.D.)
| | - William J. Duddy
- Northern Ireland Center for Stratified/Personalised Medicine, Biomedical Sciences Research Institute, Ulster University, Derry-Londonderry BT47, UK; (L.L.G.); (E.A.); (O.C.); (U.G.V.); (W.J.D.)
| | - Stephanie Duguez
- Northern Ireland Center for Stratified/Personalised Medicine, Biomedical Sciences Research Institute, Ulster University, Derry-Londonderry BT47, UK; (L.L.G.); (E.A.); (O.C.); (U.G.V.); (W.J.D.)
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27
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Flores BN, Li X, Malik AM, Martinez J, Beg AA, Barmada SJ. An Intramolecular Salt Bridge Linking TDP43 RNA Binding, Protein Stability, and TDP43-Dependent Neurodegeneration. Cell Rep 2020; 27:1133-1150.e8. [PMID: 31018129 PMCID: PMC6499398 DOI: 10.1016/j.celrep.2019.03.093] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 01/28/2019] [Accepted: 03/25/2019] [Indexed: 12/13/2022] Open
Abstract
The majority of individuals with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) exhibit neuronal cytoplasmic inclusions rich in the RNA binding protein TDP43. Even so, the relation between the RNA binding properties of TDP43 and neurodegeneration remains obscure. Here, we show that engineered mutations disrupting a salt bridge between the RNA recognition motifs of TDP43 interfere with RNA binding and eliminate the recognition of native TDP43 substrates. The same mutations dramatically destabilize TDP43, alter its subcellular localization, and abrogate TDP43-dependent neuro-degeneration. Worms harboring homologous TDP-1 mutations phenocopy knockout strains, confirming the necessity of salt bridge residues for TDP43 function. Moreover, the accumulation of functional TDP43, but not RNA binding-deficient variants, disproportionately affects transcripts encoding ribo-some and oxidative phosphorylation components. These studies demonstrate the significance of the salt bridge in sustaining TDP43 stability and RNA binding properties, factors that are crucial for neurodegeneration arising from TDP43 deposition in ALS and FTD. Flores et al. uncover essential roles for an intramolecular salt bridge in the function of TDP43, an RNA binding protein implicated in neurodegenerative diseases. Salt bridge interruption attenuates TDP43 RNA binding affinity and specificity, destabilizes the protein, and prevents TDP43-mediated neurotoxicity arising from misprocessing of ribosomal and mitochondrial transcripts.
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Affiliation(s)
- Brittany N Flores
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI 48104, USA; Department of Neurology, University of Michigan, Ann Arbor, MI 48104, USA
| | - Xingli Li
- Department of Neurology, University of Michigan, Ann Arbor, MI 48104, USA
| | - Ahmed M Malik
- Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48104, USA; Neuroscience Graduate Program, Department of Pharmacology, University of Michigan, Ann Arbor, MI 48104, USA
| | - Jose Martinez
- Neuroscience Graduate Program, Department of Pharmacology, University of Michigan, Ann Arbor, MI 48104, USA
| | - Asim A Beg
- Neuroscience Graduate Program, Department of Pharmacology, University of Michigan, Ann Arbor, MI 48104, USA
| | - Sami J Barmada
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI 48104, USA; Department of Neurology, University of Michigan, Ann Arbor, MI 48104, USA; Neuroscience Graduate Program, Department of Pharmacology, University of Michigan, Ann Arbor, MI 48104, USA.
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28
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Limanaqi F, Busceti CL, Biagioni F, Cantini F, Lenzi P, Fornai F. Cell-Clearing Systems Bridging Repeat Expansion Proteotoxicity and Neuromuscular Junction Alterations in ALS and SBMA. Int J Mol Sci 2020; 21:ijms21114021. [PMID: 32512809 PMCID: PMC7312203 DOI: 10.3390/ijms21114021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/29/2020] [Accepted: 06/03/2020] [Indexed: 12/12/2022] Open
Abstract
The coordinated activities of autophagy and the ubiquitin proteasome system (UPS) are key to preventing the aggregation and toxicity of misfold-prone proteins which manifest in a number of neurodegenerative disorders. These include proteins which are encoded by genes containing nucleotide repeat expansions. In the present review we focus on the overlapping role of autophagy and the UPS in repeat expansion proteotoxicity associated with chromosome 9 open reading frame 72 (C9ORF72) and androgen receptor (AR) genes, which are implicated in two motor neuron disorders, amyotrophic lateral sclerosis (ALS) and spinal-bulbar muscular atrophy (SBMA), respectively. At baseline, both C9ORF72 and AR regulate autophagy, while their aberrantly-expanded isoforms may lead to a failure in both autophagy and the UPS, further promoting protein aggregation and toxicity within motor neurons and skeletal muscles. Besides proteotoxicity, autophagy and UPS alterations are also implicated in neuromuscular junction (NMJ) alterations, which occur early in both ALS and SBMA. In fact, autophagy and the UPS intermingle with endocytic/secretory pathways to regulate axonal homeostasis and neurotransmission by interacting with key proteins which operate at the NMJ, such as agrin, acetylcholine receptors (AChRs), and adrenergic beta2 receptors (B2-ARs). Thus, alterations of autophagy and the UPS configure as a common hallmark in both ALS and SBMA disease progression. The findings here discussed may contribute to disclosing overlapping molecular mechanisms which are associated with a failure in cell-clearing systems in ALS and SBMA.
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Affiliation(s)
- Fiona Limanaqi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy; (F.L.); (F.C.); (P.L.)
| | | | - Francesca Biagioni
- I.R.C.C.S. Neuromed, Via Atinense, 18, 86077 Pozzilli, Italy; (C.L.B.); (F.B.)
| | - Federica Cantini
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy; (F.L.); (F.C.); (P.L.)
| | - Paola Lenzi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy; (F.L.); (F.C.); (P.L.)
| | - Francesco Fornai
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy; (F.L.); (F.C.); (P.L.)
- I.R.C.C.S. Neuromed, Via Atinense, 18, 86077 Pozzilli, Italy; (C.L.B.); (F.B.)
- Correspondence:
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29
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Puleo N, Lamitina T. The conserved multi-functional nuclear protein dss-1/Sem1 is required for C9orf72-associated ALS/FTD dipeptide toxicity. MICROPUBLICATION BIOLOGY 2020; 2020. [PMID: 32550521 PMCID: PMC7266659 DOI: 10.17912/micropub.biology.000262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Noah Puleo
- University of Pittsburgh, Depts. of Pediatrics and Cell Biology
| | - Todd Lamitina
- University of Pittsburgh, Depts. of Pediatrics and Cell Biology
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30
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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: 77] [Impact Index Per Article: 19.3] [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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31
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Glial Cells-The Strategic Targets in Amyotrophic Lateral Sclerosis Treatment. J Clin Med 2020; 9:jcm9010261. [PMID: 31963681 PMCID: PMC7020059 DOI: 10.3390/jcm9010261] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/13/2020] [Accepted: 01/16/2020] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurological disease, which is characterized by the degeneration of motor neurons in the motor cortex and the spinal cord and subsequently by muscle atrophy. To date, numerous gene mutations have been linked to both sporadic and familial ALS, but the effort of many experimental groups to develop a suitable therapy has not, as of yet, proven successful. The original focus was on the degenerating motor neurons, when researchers tried to understand the pathological mechanisms that cause their slow death. However, it was soon discovered that ALS is a complicated and diverse pathology, where not only neurons, but also other cell types, play a crucial role via the so-called non-cell autonomous effect, which strongly deteriorates neuronal conditions. Subsequently, variable glia-based in vitro and in vivo models of ALS were established and used for brand-new experimental and clinical approaches. Such a shift towards glia soon bore its fruit in the form of several clinical studies, which more or less successfully tried to ward the unfavourable prognosis of ALS progression off. In this review, we aimed to summarize current knowledge regarding the involvement of each glial cell type in the progression of ALS, currently available treatments, and to provide an overview of diverse clinical trials covering pharmacological approaches, gene, and cell therapies.
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Primary Neurons and Differentiated NSC-34 Cells Are More Susceptible to Arginine-Rich ALS Dipeptide Repeat Protein-Associated Toxicity than Non-Differentiated NSC-34 and CHO Cells. Int J Mol Sci 2019; 20:ijms20246238. [PMID: 31835664 PMCID: PMC6941034 DOI: 10.3390/ijms20246238] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 12/02/2019] [Accepted: 12/09/2019] [Indexed: 12/14/2022] Open
Abstract
A repeat expansion mutation in the C9orf72 gene is the most common known genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). In this study, using multiple cell-based assay systems, we reveal both increased dipeptide repeat protein (DRP) toxicity in primary neurons and in differentiated neuronal cell lines. Using flow cytometry and confocal laser scanning microscopy of cells treated with fluorescein isothiocyanate (FITC)-labeled DRPs, we confirm that poly-glycine-arginine (GR) and poly-proline-arginine (PR) DRPs entered cells more readily than poly-glycine-proline (GP) and poly-proline-alanine (PA) DRPs. Our findings suggest that the toxicity of C9-DRPs may be influenced by properties associated with differentiated and aging motor neurons. Further, our findings provide sensitive cell-based assay systems to test phenotypic rescue ability of potential interventions.
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33
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Hui KK, Chen YK, Endo R, Tanaka M. Translation from the Ribosome to the Clinic: Implication in Neurological Disorders and New Perspectives from Recent Advances. Biomolecules 2019; 9:E680. [PMID: 31683805 PMCID: PMC6920867 DOI: 10.3390/biom9110680] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 10/27/2019] [Accepted: 10/29/2019] [Indexed: 12/12/2022] Open
Abstract
De novo protein synthesis by the ribosome and its multitude of co-factors must occur in a tightly regulated manner to ensure that the correct proteins are produced accurately at the right time and, in some cases, also in the proper location. With novel techniques such as ribosome profiling and cryogenic electron microscopy, our understanding of this basic biological process is better than ever and continues to grow. Concurrently, increasing attention is focused on how translational regulation in the brain may be disrupted during the progression of various neurological disorders. In fact, translational dysregulation is now recognized as the de facto pathogenic cause for some disorders. Novel mechanisms including ribosome stalling, ribosome-associated quality control, and liquid-liquid phase separation are closely linked to translational regulation, and may thus be involved in the pathogenic process. The relationships between translational dysregulation and neurological disorders, as well as the ways through which we may be able to reverse those detrimental effects, will be examined in this review.
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Affiliation(s)
- Kelvin K Hui
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan.
| | - Yi-Kai Chen
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan.
| | - Ryo Endo
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan.
| | - Motomasa Tanaka
- Laboratory for Protein Conformation Diseases, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan.
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34
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C9orf72 Proteins Regulate Autophagy and Undergo Autophagosomal or Proteasomal Degradation in a Cell Type-Dependent Manner. Cells 2019; 8:cells8101233. [PMID: 31658762 PMCID: PMC6829620 DOI: 10.3390/cells8101233] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/08/2019] [Accepted: 10/10/2019] [Indexed: 12/11/2022] Open
Abstract
Dysfunctional autophagy or ubiquitin-proteasome system (UPS) are suggested to underlie abnormal protein aggregation in neurodegenerative diseases. Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS)-associated C9orf72 is implicated in autophagy, but whether it activates or inhibits autophagy is partially controversial. Here, we utilized knockdown or overexpression of C9orf72 in mouse N2a neuroblastoma cells or cultured neurons to elucidate the potential role of C9orf72 proteins in autophagy and UPS. Induction of autophagy in C9orf72 knockdown N2a cells led to decreased LC3BI to LC3BII conversion, p62 degradation, and formation of LC3-containing autophagosomes, suggesting compromised autophagy. Proteasomal activity was slightly decreased. No changes in autophagy nor proteasomal activity in C9orf72-overexpressing N2a cells were observed. However, in these cells, autophagy induction by serum starvation or rapamycin led to significantly decreased C9orf72 levels. The decreased levels of C9orf72 in serum-starved N2a cells were restored by the proteasomal inhibitor lactacystin, but not by the autophagy inhibitor bafilomycin A1 (BafA1) treatment. These data suggest that C9orf72 undergoes proteasomal degradation in N2a cells during autophagy. Lactacystin significantly elevated C9orf72 levels in N2a cells and neurons, further suggesting UPS-mediated regulation. In rapamycin and BafA1-treated neurons, C9orf72 levels were significantly increased. Altogether, these findings corroborate the previously suggested regulatory role for C9orf72 in autophagy and suggest cell type-dependent regulation of C9orf72 levels via UPS and/or autophagy.
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Abstract
The discovery that repeat expansions in the C9orf72 gene are a frequent cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) has revolutionized our understanding of these diseases. Substantial headway has been made in characterizing C9orf72-mediated disease and unravelling its underlying aetiopathogenesis. Three main disease mechanisms have been proposed: loss of function of the C9orf72 protein and toxic gain of function from C9orf72 repeat RNA or from dipeptide repeat proteins produced by repeat-associated non-ATG translation. Several downstream processes across a range of cellular functions have also been implicated. In this article, we review the pathological and mechanistic features of C9orf72-associated FTD and ALS (collectively termed C9FTD/ALS), the model systems used to study these conditions, and the probable initiators of downstream disease mechanisms. We suggest that a combination of upstream mechanisms involving both loss and gain of function and downstream cellular pathways involving both cell-autonomous and non-cell-autonomous effects contributes to disease progression.
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Affiliation(s)
- Rubika Balendra
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK.,Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, UCL, London, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK. .,UK Dementia Research Institute at UCL, UCL Institute of Neurology, London, UK.
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36
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L3MBTL1 regulates ALS/FTD-associated proteotoxicity and quality control. Nat Neurosci 2019; 22:875-886. [PMID: 31061493 PMCID: PMC6588399 DOI: 10.1038/s41593-019-0384-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 03/13/2019] [Indexed: 12/13/2022]
Abstract
Misfolded protein toxicity and failure of protein quality control
underlie neurodegenerative diseases including amyotrophic lateral sclerosis
(ALS) and frontotemporal dementia (FTD). Here, we identified Lethal(3)malignant
brain tumor-like protein 1 (L3MBTL1) as a previously unknown regulator of
protein quality control, the loss of which protected against the proteotoxicity
of mutant SOD1 or C9orf72 dipeptide repeat proteins. L3MBTL1 acts by regulating
p53-dependent quality control systems that degrade misfolded proteins. SET
domain-containing protein 8 (SETD8), a L3MBTL1-associatd p53-binding protein,
also regulated clearance of misfolded proteins and was increased by
proteotoxicity-associated stresses in mammalian cells. Both L3MBTL1 and SETD8
were up-regulated in the central nervous systems of mouse models of ALS and
human ALS/FTD patients. The role of L3MBTL1 in protein quality control is
conserved from C. elegans to mammalian neurons. These results
indicate a previously unrecognized pathway in both normal stress response and
proteotoxicity-associated neurodegenerative diseases.
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37
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White MR, Mitrea DM, Zhang P, Stanley CB, Cassidy DE, Nourse A, Phillips AH, Tolbert M, Taylor JP, Kriwacki RW. C9orf72 Poly(PR) Dipeptide Repeats Disturb Biomolecular Phase Separation and Disrupt Nucleolar Function. Mol Cell 2019; 74:713-728.e6. [PMID: 30981631 DOI: 10.1016/j.molcel.2019.03.019] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 02/12/2019] [Accepted: 03/18/2019] [Indexed: 12/11/2022]
Abstract
Repeat expansion in the C9orf72 gene is the most common cause of the neurodegenerative disorder amyotrophic lateral sclerosis (C9-ALS) and is linked to the unconventional translation of five dipeptide-repeat polypeptides (DPRs). The two enriched in arginine, poly(GR) and poly(PR), infiltrate liquid-like nucleoli, co-localize with the nucleolar protein nucleophosmin (NPM1), and alter the phase separation behavior of NPM1 in vitro. Here, we show that poly(PR) DPRs bind tightly to a long acidic tract within the intrinsically disordered region of NPM1, altering its phase separation with nucleolar partners to the extreme of forming large, soluble complexes that cause droplet dissolution in vitro. In cells, poly(PR) DPRs disperse NPM1 from nucleoli and entrap rRNA in static condensates in a DPR-length-dependent manner. We propose that R-rich DPR toxicity involves disrupting the role of phase separation by NPM1 in organizing ribosomal proteins and RNAs within the nucleolus.
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Affiliation(s)
- Michael R White
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Diana M Mitrea
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Peipei Zhang
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Christopher B Stanley
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Devon E Cassidy
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Amanda Nourse
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Molecular Interaction Analysis Shared Resource, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Aaron H Phillips
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Michele Tolbert
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - J Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Howard Hughes Medical Institute, Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Richard W Kriwacki
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN 38105, USA.
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38
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Weskamp K, Safren N, Miguez R, Barmada S. Monitoring Neuronal Survival via Longitudinal Fluorescence Microscopy. J Vis Exp 2019. [PMID: 30735193 DOI: 10.3791/59036] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Standard cytotoxicity assays, which require the collection of lysates or fixed cells at multiple time points, have limited sensitivity and capacity to assess factors that influence neuronal fate. These assays require the observation of separate populations of cells at discrete time points. As a result, individual cells cannot be followed prospectively over time, severely limiting the ability to discriminate whether subcellular events, such as puncta formation or protein mislocalization, are pathogenic drivers of disease, homeostatic responses, or merely coincidental phenomena. Single-cell longitudinal microscopy overcomes these limitations, allowing the researcher to determine differences in survival between populations and draw causal relationships with enhanced sensitivity. This video guide will outline a representative workflow for experiments measuring single-cell survival of rat primary cortical neurons expressing a fluorescent protein marker. The viewer will learn how to achieve high-efficiency transfections, collect and process images enabling the prospective tracking of individual cells, and compare the relative survival of neuronal populations using Cox proportional hazards analysis.
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Affiliation(s)
- Kaitlin Weskamp
- Department of Neurology, University of Michigan School of Medicine; Neuroscience Graduate Program, University of Michigan School of Medicine
| | - Nathaniel Safren
- Department of Neurology, University of Michigan School of Medicine
| | - Roberto Miguez
- Department of Neurology, University of Michigan School of Medicine
| | - Sami Barmada
- Department of Neurology, University of Michigan School of Medicine; Neuroscience Graduate Program, University of Michigan School of Medicine;
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Molecular Mechanisms of Neurodegeneration Related to C9orf72 Hexanucleotide Repeat Expansion. Behav Neurol 2019; 2019:2909168. [PMID: 30774737 PMCID: PMC6350563 DOI: 10.1155/2019/2909168] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/28/2018] [Accepted: 09/18/2018] [Indexed: 12/11/2022] Open
Abstract
Two clinically distinct diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), have recently been classified as two extremes of the FTD/ALS spectrum. The neuropathological correlate of FTD is frontotemporal lobar degeneration (FTLD), characterized by tau-, TDP-43-, and FUS-immunoreactive neuronal inclusions. An earlier discovery that a hexanucleotide repeat expansion mutation in chromosome 9 open reading frame 72 (C9orf72) gene causes ALS and FTD established a special subtype of ALS and FTLD with TDP-43 pathology (C9FTD/ALS). Normal individuals carry 2–10 hexanucleotide GGGGCC repeats in the C9orf72 gene, while more than a few hundred repeats represent a risk for ALS and FTD. The proposed molecular mechanisms by which C9orf72 repeat expansions induce neurodegenerative changes are C9orf72 loss-of-function through haploinsufficiency, RNA toxic gain-of-function, and gain-of-function through the accumulation of toxic dipeptide repeat proteins. However, many more cellular processes are affected by pathological processes in C9FTD/ALS, including nucleocytoplasmic transport, RNA processing, normal function of nucleolus, formation of membraneless organelles, translation, ubiquitin proteasome system, Notch signalling pathway, granule transport, and normal function of TAR DNA-binding protein 43 (TDP-43). Although the exact molecular mechanisms through which C9orf72 repeat expansions account for neurodegeneration have not been elucidated, some potential therapeutics, such as antisense oligonucleotides targeting hexanucleotide GGGGCC repeats in mRNA, were successful in preclinical trials and are awaiting phase 1 clinical trials. In this review, we critically discuss each proposed mechanism and provide insight into the most recent studies aiming to elucidate the molecular underpinnings of C9FTD/ALS.
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40
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Latina V, Caioli S, Zona C, Ciotti MT, Borreca A, Calissano P, Amadoro G. NGF-Dependent Changes in Ubiquitin Homeostasis Trigger Early Cholinergic Degeneration in Cellular and Animal AD-Model. Front Cell Neurosci 2018; 12:487. [PMID: 30618634 PMCID: PMC6300588 DOI: 10.3389/fncel.2018.00487] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/29/2018] [Indexed: 01/20/2023] Open
Abstract
Basal forebrain cholinergic neurons (BFCNs) depend on nerve growth factor (NGF) for their survival/differentiation and innervate cortical and hippocampal regions involved in memory/learning processes. Cholinergic hypofunction and/or degeneration early occurs at prodromal stages of Alzheimer's disease (AD) neuropathology in correlation with synaptic damages, cognitive decline and behavioral disability. Alteration(s) in ubiquitin-proteasome system (UPS) is also a pivotal AD hallmark but whether it plays a causative, or only a secondary role, in early synaptic failure associated with disease onset remains unclear. We previously reported that impairment of NGF/TrkA signaling pathway in cholinergic-enriched septo-hippocampal primary neurons triggers "dying-back" degenerative processes which occur prior to cell death in concomitance with loss of specific vesicle trafficking proteins, including synapsin I, SNAP-25 and α-synuclein, and with deficit in presynaptic excitatory neurotransmission. Here, we show that in this in vitro neuronal model: (i) UPS stimulation early occurs following neurotrophin starvation (-1 h up to -6 h); (ii) NGF controls the steady-state levels of these three presynaptic proteins by acting on coordinate mechanism(s) of dynamic ubiquitin-C-terminal hydrolase 1 (UCHL-1)-dependent (mono)ubiquitin turnover and UPS-mediated protein degradation. Importantly, changes in miniature excitatory post-synaptic currents (mEPSCs) frequency detected in -6 h NGF-deprived primary neurons are strongly reverted by acute inhibition of UPS and UCHL-1, indicating that NGF tightly controls in vitro the presynaptic efficacy via ubiquitination-mediated pathway(s). Finally, changes in synaptic ubiquitin and selective reduction of presynaptic markers are also found in vivo in cholinergic nerve terminals from hippocampi of transgenic Tg2576 AD mice, even from presymptomatic stages of neuropathology (1-month-old). By demonstrating a crucial role of UPS in the dysregulation of NGF/TrkA signaling on properties of cholinergic synapses, these findings from two well-established cellular and animal AD models provide novel therapeutic targets to contrast early cognitive and synaptic dysfunction associated to selective degeneration of BFCNs occurring in incipient early/middle-stage of disease.
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Affiliation(s)
| | | | - Cristina Zona
- IRCCS Santa Lucia Foundation, Rome, Italy
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | | | - Antonella Borreca
- Institute of Cellular Biology and Neurobiology – National Research Council, Rome, Italy
| | | | - Giuseppina Amadoro
- European Brain Research Institute, Rome, Italy
- Institute of Translational Pharmacology – National Research Council, Rome, Italy
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41
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Glineburg MR, Todd PK, Charlet-Berguerand N, Sellier C. Repeat-associated non-AUG (RAN) translation and other molecular mechanisms in Fragile X Tremor Ataxia Syndrome. Brain Res 2018; 1693:43-54. [PMID: 29453961 PMCID: PMC6010627 DOI: 10.1016/j.brainres.2018.02.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/31/2018] [Accepted: 02/02/2018] [Indexed: 11/11/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset inherited neurodegenerative disorder characterized by progressive intention tremor, gait ataxia and dementia associated with mild brain atrophy. The cause of FXTAS is a premutation expansion, of 55 to 200 CGG repeats localized within the 5'UTR of FMR1. These repeats are transcribed in the sense and antisense directions into mutants RNAs, which have increased expression in FXTAS. Furthermore, CGG sense and CCG antisense expanded repeats are translated into novel proteins despite their localization in putatively non-coding regions of the transcript. Here we focus on two proposed disease mechanisms for FXTAS: 1) RNA gain-of-function, whereby the mutant RNAs bind specific proteins and preclude their normal functions, and 2) repeat-associated non-AUG (RAN) translation, whereby translation through the CGG or CCG repeats leads to the production of toxic homopolypeptides, which in turn interfere with a variety of cellular functions. Here, we analyze the data generated to date on both of these potential molecular mechanisms and lay out a path forward for determining which factors drive FXTAS pathogenicity.
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Affiliation(s)
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Veteran's Affairs Medical Center, Ann Arbor, MI 48105, USA
| | - Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Chantal Sellier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France.
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42
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Malik AM, Miguez RA, Li X, Ho YS, Feldman EL, Barmada SJ. Matrin 3-dependent neurotoxicity is modified by nucleic acid binding and nucleocytoplasmic localization. eLife 2018; 7:e35977. [PMID: 30015619 PMCID: PMC6050042 DOI: 10.7554/elife.35977] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 07/01/2018] [Indexed: 12/12/2022] Open
Abstract
Abnormalities in nucleic acid processing are associated with the development of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Mutations in Matrin 3 (MATR3), a poorly understood DNA- and RNA-binding protein, cause familial ALS/FTD, and MATR3 pathology is a feature of sporadic disease, suggesting that MATR3 dysfunction is integrally linked to ALS pathogenesis. Using a rat primary neuron model to assess MATR3-mediated toxicity, we noted that neurons were bidirectionally vulnerable to MATR3 levels, with pathogenic MATR3 mutants displaying enhanced toxicity. MATR3's zinc finger domains partially modulated toxicity, but elimination of its RNA recognition motifs had no effect on survival, instead facilitating its self-assembly into liquid-like droplets. In contrast to other RNA-binding proteins associated with ALS, cytoplasmic MATR3 redistribution mitigated neurodegeneration, suggesting that nuclear MATR3 mediates toxicity. Our findings offer a foundation for understanding MATR3-related neurodegeneration and how nucleic acid binding functions, localization, and pathogenic mutations drive sporadic and familial disease.
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Affiliation(s)
- Ahmed M Malik
- Medical Scientist Training ProgramUniversity of MichiganAnn ArborUnited States
- Neuroscience Graduate ProgramUniversity of MichiganAnn ArborUnited States
| | - Roberto A Miguez
- Department of NeurologyUniversity of MichiganAnn ArborUnited States
| | - Xingli Li
- Department of NeurologyUniversity of MichiganAnn ArborUnited States
| | - Ye-Shih Ho
- Institute of Environmental Health SciencesWayne State UniversityDetroitUnited States
| | - Eva L Feldman
- Neuroscience Graduate ProgramUniversity of MichiganAnn ArborUnited States
- Department of NeurologyUniversity of MichiganAnn ArborUnited States
- Program for Neurology Research and DiscoveryUniversity of MichiganAnn ArborUnited States
| | - Sami J Barmada
- Neuroscience Graduate ProgramUniversity of MichiganAnn ArborUnited States
- Department of NeurologyUniversity of MichiganAnn ArborUnited States
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43
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Park S, Lee JH, Jeon JH, Lee MJ. Degradation or aggregation: the ramifications of post-translational modifications on tau. BMB Rep 2018; 51:265-273. [PMID: 29661268 PMCID: PMC6033068 DOI: 10.5483/bmbrep.2018.51.6.077] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Indexed: 01/06/2023] Open
Abstract
Tau protein is encoded in the microtubule-associated protein tau (MAPT) gene and contributes to the stability of microtubules in axons. Despite of its basic isoelectric point and high solubility, tau is often found in intraneuronal filamentous inclusions such as paired helical filaments (PHFs), which are the primary constituent of neurofibrillary tangles (NFTs). This pathological feature is the nosological entity termed "tauopathies" which notably include Alzheimer's disease (AD). A proteinaceous signature of all tauopathies is hyperphosphorylation of the accumulated tau, which has been extensively studied as a major pharmacological target for AD therapy. However, in addition to phosphorylation events, tau undergoes a number of diverse posttranslational modifications (PTMs) which appear to be controlled by complex crosstalk. It remains to be elucidated which of the PTMs or their combinations have pro-aggregation or anti-aggregation properties. In this review, we outline the consequences of and communications between several key PTMs of tau, such as acetylation, phosphorylation, and ubiquitination, focusing on their roles in aggregation and degradation. We place emphasis on the structure of tau protofilaments from the human AD brain, which may be good targets to modulate etiological PTMs which cause tau aggregation. [BMB Reports 2018; 51(6): 265-273].
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Affiliation(s)
- Seoyoung Park
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 03080,
Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 03080,
Korea
| | - Jung Hoon Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 03080,
Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 03080,
Korea
| | - Jun Hyoung Jeon
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 03080,
Korea
| | - Min Jae Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 03080,
Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 03080,
Korea
- Department of Biomedical Sciences, Seoul National University Graduate School, Seoul 03080,
Korea
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44
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Walker C, El-Khamisy SF. Perturbed autophagy and DNA repair converge to promote neurodegeneration in amyotrophic lateral sclerosis and dementia. Brain 2018; 141:1247-1262. [PMID: 29584802 PMCID: PMC5917746 DOI: 10.1093/brain/awy076] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 01/16/2018] [Accepted: 02/09/2018] [Indexed: 12/13/2022] Open
Abstract
Maintaining genomic stability constitutes a major challenge facing cells. DNA breaks can arise from direct oxidative damage to the DNA backbone, the inappropriate activities of endogenous enzymes such as DNA topoisomerases, or due to transcriptionally-derived RNA/DNA hybrids (R-loops). The progressive accumulation of DNA breaks has been linked to several neurological disorders. Recently, however, several independent studies have implicated nuclear and mitochondrial genomic instability, perturbed co-transcriptional processing, and impaired cellular clearance pathways as causal and intertwined mechanisms underpinning neurodegeneration. Here, we discuss this emerging paradigm in the context of amyotrophic lateral sclerosis and frontotemporal dementia, and outline how this knowledge paves the way to novel therapeutic interventions.
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Affiliation(s)
- Callum Walker
- Krebs Institute, Department of Molecular biology and biotechnology, University of Sheffield, UK
- The Institute of Cancer Research, London, UK
| | - Sherif F El-Khamisy
- Krebs Institute, Department of Molecular biology and biotechnology, University of Sheffield, UK
- Center for Genomics, Helmy Institute for Medical Sciences, Zewail City of Science and Technology, Giza, Egypt
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45
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Maurel C, Dangoumau A, Marouillat S, Brulard C, Chami A, Hergesheimer R, Corcia P, Blasco H, Andres CR, Vourc'h P. Causative Genes in Amyotrophic Lateral Sclerosis and Protein Degradation Pathways: a Link to Neurodegeneration. Mol Neurobiol 2018; 55:6480-6499. [PMID: 29322304 DOI: 10.1007/s12035-017-0856-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 12/20/2017] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a disease caused by the degeneration of motor neurons (MNs) leading to progressive muscle weakness and atrophy. Several molecular pathways have been implicated, such as glutamate-mediated excitotoxicity, defects in cytoskeletal dynamics and axonal transport, disruption of RNA metabolism, and impairments in proteostasis. ALS is associated with protein accumulation in the cytoplasm of cells undergoing neurodegeneration, which is a hallmark of the disease. In this review, we focus on mechanisms of proteostasis, particularly protein degradation, and discuss how they are related to the genetics of ALS. Indeed, the genetic bases of the disease with the implication of more than 30 genes associated with familial ALS to date, together with the important increase in understanding of endoplasmic reticulum (ER) stress, proteasomal degradation, and autophagy, allow researchers to better understand the mechanisms underlying the selective death of motor neurons in ALS. It is clear that defects in proteostasis are involved in this type of cellular degeneration, but whether or not these mechanisms are primary causes or merely consequential remains to be clearly demonstrated. Novel cellular and animal models allowing chronic expression of mutant proteins, for example, are required. Further studies linking genetic discoveries in ALS to mechanisms of protein clearance will certainly be crucial in order to accelerate translational and clinical research towards new therapeutic targets and strategies.
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Affiliation(s)
- C Maurel
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - A Dangoumau
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - S Marouillat
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - C Brulard
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - A Chami
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - R Hergesheimer
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - P Corcia
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Neurologie, CHRU de Tours, 37044, Tours, France
| | - H Blasco
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France
| | - C R Andres
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France
| | - P Vourc'h
- UMR INSERM U1253, Université de Tours, 37032, Tours, France.
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France.
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46
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Al-Ramahi I, Giridharan SSP, Chen YC, Patnaik S, Safren N, Hasegawa J, de Haro M, Wagner Gee AK, Titus SA, Jeong H, Clarke J, Krainc D, Zheng W, Irvine RF, Barmada S, Ferrer M, Southall N, Weisman LS, Botas J, Marugan JJ. Inhibition of PIP4Kγ ameliorates the pathological effects of mutant huntingtin protein. eLife 2017; 6:29123. [PMID: 29256861 PMCID: PMC5743427 DOI: 10.7554/elife.29123] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 11/13/2017] [Indexed: 12/15/2022] Open
Abstract
The discovery of the causative gene for Huntington’s disease (HD) has promoted numerous efforts to uncover cellular pathways that lower levels of mutant huntingtin protein (mHtt) and potentially forestall the appearance of HD-related neurological defects. Using a cell-based model of pathogenic huntingtin expression, we identified a class of compounds that protect cells through selective inhibition of a lipid kinase, PIP4Kγ. Pharmacological inhibition or knock-down of PIP4Kγ modulates the equilibrium between phosphatidylinositide (PI) species within the cell and increases basal autophagy, reducing the total amount of mHtt protein in human patient fibroblasts and aggregates in neurons. In two Drosophila models of Huntington’s disease, genetic knockdown of PIP4K ameliorated neuronal dysfunction and degeneration as assessed using motor performance and retinal degeneration assays respectively. Together, these results suggest that PIP4Kγ is a druggable target whose inhibition enhances productive autophagy and mHtt proteolysis, revealing a useful pharmacological point of intervention for the treatment of Huntington’s disease, and potentially for other neurodegenerative disorders.
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Affiliation(s)
- Ismael Al-Ramahi
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Baylor College of Medicine, Texas Medical Center, Houston, United States
| | | | - Yu-Chi Chen
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Samarjit Patnaik
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Nathaniel Safren
- Department of Neurology, University of Michigan, Ann Arbor, United States
| | - Junya Hasegawa
- Department of Cell and Developmental Biology, Life Sciences Institute, University of Michigan, Ann Arbor, United States
| | - Maria de Haro
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Baylor College of Medicine, Texas Medical Center, Houston, United States
| | - Amanda K Wagner Gee
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Steven A Titus
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Hyunkyung Jeong
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Jonathan Clarke
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Dimitri Krainc
- The Ken and Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Wei Zheng
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Robin F Irvine
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Sami Barmada
- Department of Neurology, University of Michigan, Ann Arbor, United States
| | - Marc Ferrer
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Noel Southall
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
| | - Lois S Weisman
- Department of Cell and Developmental Biology, Life Sciences Institute, University of Michigan, Ann Arbor, United States
| | - Juan Botas
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Baylor College of Medicine, Texas Medical Center, Houston, United States
| | - Juan Jose Marugan
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, United States
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47
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Kapur M, Monaghan CE, Ackerman SL. Regulation of mRNA Translation in Neurons-A Matter of Life and Death. Neuron 2017; 96:616-637. [PMID: 29096076 DOI: 10.1016/j.neuron.2017.09.057] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 09/20/2017] [Accepted: 09/28/2017] [Indexed: 12/14/2022]
Abstract
Dynamic regulation of mRNA translation initiation and elongation is essential for the survival and function of neural cells. Global reductions in translation initiation resulting from mutations in the translational machinery or inappropriate activation of the integrated stress response may contribute to pathogenesis in a subset of neurodegenerative disorders. Aberrant proteins generated by non-canonical translation initiation may be a factor in the neuron death observed in the nucleotide repeat expansion diseases. Dysfunction of central components of the elongation machinery, such as the tRNAs and their associated enzymes, can cause translational infidelity and ribosome stalling, resulting in neurodegeneration. Taken together, dysregulation of mRNA translation is emerging as a unifying mechanism underlying the pathogenesis of many neurodegenerative disorders.
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Affiliation(s)
- Mridu Kapur
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Caitlin E Monaghan
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA.
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48
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Nassif M, Woehlbier U, Manque PA. The Enigmatic Role of C9ORF72 in Autophagy. Front Neurosci 2017; 11:442. [PMID: 28824365 PMCID: PMC5541066 DOI: 10.3389/fnins.2017.00442] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/19/2017] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by the loss of motor neurons resulting in a progressive and irreversible muscular paralysis. Advances in large-scale genetics and genomics have revealed intronic hexanucleotide repeat expansions in the gene encoding C9ORF72 as a main genetic cause of ALS and frontotemporal dementia (FTD), the second most common cause of early-onset dementia after Alzheimer's disease. Novel insights regarding the underlying pathogenic mechanisms of C9ORF72 seem to suggest a synergy of loss and gain of toxic function during disease. C9ORF72, thus far, has been found to be involved in homeostatic cellular pathways, such as actin dynamics, regulation of membrane trafficking, and macroautophagy. All these pathways have been found compromised in the pathogenesis of ALS. In this review, we aim to summarize recent findings on the function of C9ORF72, particularly in the macroautophagy pathway, hinting at a requirement to maintain the fine balance of macroautophagy to prevent neurodegeneration.
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Affiliation(s)
- Melissa Nassif
- Faculty of Science, Center for Integrative Biology, Universidad MayorSantiago, Chile.,Faculty of Science, Center for Genomics and Bioinformatics, Universidad MayorSantiago, Chile
| | - Ute Woehlbier
- Faculty of Science, Center for Integrative Biology, Universidad MayorSantiago, Chile.,Faculty of Science, Center for Genomics and Bioinformatics, Universidad MayorSantiago, Chile
| | - Patricio A Manque
- Faculty of Science, Center for Integrative Biology, Universidad MayorSantiago, Chile.,Faculty of Science, Center for Genomics and Bioinformatics, Universidad MayorSantiago, Chile
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49
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Budini M, Buratti E, Morselli E, Criollo A. Autophagy and Its Impact on Neurodegenerative Diseases: New Roles for TDP-43 and C9orf72. Front Mol Neurosci 2017; 10:170. [PMID: 28611593 PMCID: PMC5447761 DOI: 10.3389/fnmol.2017.00170] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 05/15/2017] [Indexed: 12/12/2022] Open
Abstract
Autophagy is a catabolic mechanism where intracellular material is degraded by vesicular structures called autophagolysosomes. Autophagy is necessary to maintain the normal function of the central nervous system (CNS), avoiding the accumulation of misfolded and aggregated proteins. Consistently, impaired autophagy has been associated with the pathogenesis of various neurodegenerative diseases. The proteins TAR DNA-binding protein-43 (TDP-43), which regulates RNA processing at different levels, and chromosome 9 open reading frame 72 (C9orf72), probably involved in membrane trafficking, are crucial in the development of neurodegenerative diseases such as Amyotrophic lateral sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD). Additionally, recent studies have identified a role for these proteins in the control of autophagy. In this manuscript, we review what is known regarding the autophagic mechanism and discuss the involvement of TDP-43 and C9orf72 in autophagy and their impact on neurodegenerative diseases.
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Affiliation(s)
- Mauricio Budini
- Dentistry Faculty, Institute in Dentistry Sciences, University of ChileSantiago, Chile
| | - Emanuele Buratti
- International Centre for Genetic Engineering and BiotechnologyTrieste, Italy
| | - Eugenia Morselli
- Department of Physiology, Faculty of Biological Sciences, Pontificia Universidad Católica de ChileSantiago, Chile
| | - Alfredo Criollo
- Dentistry Faculty, Institute in Dentistry Sciences, University of ChileSantiago, Chile.,Advanced Center for Chronic DiseasesSantiago, Chile
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