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Gomez N, Hsieh C, Li X, Dykstra M, Waksmacki J, Altheim C, Bechar Y, Klim J, Zaepfel B, Rothstein J, Tank EE, Barmada SJ. Counter-regulation of RNA stability by UPF1 and TDP43. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.31.578310. [PMID: 38352350 PMCID: PMC10862862 DOI: 10.1101/2024.01.31.578310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
RNA quality control is crucial for proper regulation of gene expression. Disruption of nonsense mediated mRNA decay (NMD), the primary RNA decay pathway responsible for the degradation of transcripts containing premature termination codons (PTCs), can disrupt development and lead to multiple diseases in humans and other animals. Similarly, therapies targeting NMD may have applications in hematological, neoplastic and neurological disorders. As such, tools capable of accurately quantifying NMD status could be invaluable for investigations of disease pathogenesis and biomarker identification. Toward this end, we assemble, validate, and apply a next-generation sequencing approach (NMDq) for identifying and measuring the abundance of PTC-containing transcripts. After validating NMDq performance and confirming its utility for tracking RNA surveillance, we apply it to determine pathway activity in two neurodegenerative diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) characterized by RNA misprocessing and abnormal RNA stability. Despite the genetic and pathologic evidence implicating dysfunctional RNA metabolism, and NMD in particular, in these conditions, we detected no significant differences in PTC-encoding transcripts in ALS models or disease. Contrary to expectations, overexpression of the master NMD regulator UPF1 had little effect on the clearance of transcripts with PTCs, but rather restored RNA homeostasis through differential use and decay of alternatively poly-adenylated isoforms. Together, these data suggest that canonical NMD is not a significant contributor to ALS/FTD pathogenesis, and that UPF1 promotes neuronal survival by regulating transcripts with abnormally long 3'UTRs.
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2
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Romo L, Findlay SD, Burge CB. Regulatory features aid interpretation of 3'UTR variants. Am J Hum Genet 2024; 111:350-363. [PMID: 38237594 PMCID: PMC10870128 DOI: 10.1016/j.ajhg.2023.12.017] [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: 08/01/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 01/30/2024] Open
Abstract
Our ability to determine the clinical impact of variants in 3' untranslated regions (UTRs) of genes remains poor. We provide a thorough analysis of 3' UTR variants from several datasets. Variants in putative regulatory elements, including RNA-binding protein motifs, eCLIP peaks, and microRNA sites, are up to 16 times more likely than variants not in these elements to have gene expression and phenotype associations. Variants in regulatory motifs result in allele-specific protein binding in cell lines and allele-specific gene expression differences in population studies. In addition, variants in shared regions of alternatively polyadenylated isoforms and those proximal to polyA sites are more likely to affect gene expression and phenotype. Finally, pathogenic 3' UTR variants in ClinVar are up to 20 times more likely than benign variants to fall in a regulatory site. We incorporated these findings into RegVar, a software tool that interprets regulatory elements and annotations for any 3' UTR variant and predicts whether the variant is likely to affect gene expression or phenotype. This tool will help prioritize variants for experimental studies and identify pathogenic variants in individuals.
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Affiliation(s)
- Lindsay Romo
- Harvard Medical Genetics Training Program, Boston Children's Hospital, Boston, MA 02115, USA.
| | - Scott D Findlay
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Christopher B Burge
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
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3
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Zecca C, Tortelli R, Carrera P, Dell'Abate MT, Logroscino G, Ferrari M. Genotype-phenotype correlation in the spectrum of frontotemporal dementia-parkinsonian syndromes and advanced diagnostic approaches. Crit Rev Clin Lab Sci 2022; 60:171-188. [PMID: 36510705 DOI: 10.1080/10408363.2022.2150833] [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: 12/15/2022]
Abstract
The term frontotemporal dementia (FTD) refers to a group of progressive neurodegenerative disorders characterized mainly by atrophy of the frontal and anterior temporal lobes. Based on clinical presentation, three main clinical syndromes have traditionally been described: behavioral variant frontotemporal dementia (bvFTD), non-fluent/agrammatic primary progressive aphasia (nfPPA), and semantic variant PPA (svPPA). However, over the last 20 years, it has been recognized that cognitive phenotypes often overlap with motor phenotypes, either motor neuron diseases or parkinsonian signs and/or syndromes like progressive supranuclear palsy (PSP) and cortico-basal syndrome (CBS). Furthermore, FTD-related genes are characterized by genetic pleiotropy and can cause, even in the same family, pure motor phenotypes, findings that underlie the clinical continuum of the spectrum, which has pure cognitive and pure motor phenotypes as the extremes. The genotype-phenotype correlation of the spectrum, FTD-motor neuron disease, has been well defined and extensively investigated, while the continuum, FTD-parkinsonism, lacks a comprehensive review. In this narrative review, we describe the current knowledge about the genotype-phenotype correlation of the spectrum, FTD-parkinsonism, focusing on the phenotypes that are less frequent than bvFTD, namely nfPPA, svPPA, PSP, CBS, and cognitive-motor overlapping phenotypes (i.e. PPA + PSP). From a pathological point of view, they are characterized mainly by the presence of phosphorylated-tau inclusions, either 4 R or 3 R. The genetic correlate of the spectrum can be heterogeneous, although some variants seem to lead preferentially to specific clinical syndromes. Furthermore, we critically review the contribution of genome-wide association studies (GWAS) and next-generation sequencing (NGS) in disentangling the complex heritability of the FTD-parkinsonism spectrum and in defining the genotype-phenotype correlation of the entire clinical scenario, owing to the ability of these techniques to test multiple genes, and so to allow detailed investigations of the overlapping phenotypes. Finally, we conclude with the importance of a detailed genetic characterization and we offer to patients and families the chance to be included in future randomized clinical trials focused on autosomal dominant forms of FTLD.
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Affiliation(s)
- Chiara Zecca
- Department of Clinical Research in Neurology, Center for Neurodegenerative Diseases and the Aging Brain, University of Bari "Aldo Moro", Pia Fondazione Card G. Panico Hospital, Tricase, Italy
| | - Rosanna Tortelli
- Neuroscience and Rare Diseases Discovery and Translational Area, Roche Pharma Research and Early Development, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Paola Carrera
- Unit of Genomics for Human Disease Diagnosis and Clinical Molecular Biology Laboratory, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Maria Teresa Dell'Abate
- Department of Clinical Research in Neurology, Center for Neurodegenerative Diseases and the Aging Brain, University of Bari "Aldo Moro", Pia Fondazione Card G. Panico Hospital, Tricase, Italy
| | - Giancarlo Logroscino
- Department of Clinical Research in Neurology, Center for Neurodegenerative Diseases and the Aging Brain, University of Bari "Aldo Moro", Pia Fondazione Card G. Panico Hospital, Tricase, Italy.,Department of Basic Medicine Sciences, Neuroscience, and Sense Organs, University of Bari "Aldo Moro", Bari, Italy
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4
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Park SK, Park S, Liebman SW. TDP-43 Toxicity in Yeast Is Associated with a Reduction in Autophagy, and Deletions of TIP41 and PBP1 Counteract These Effects. Viruses 2022; 14:2264. [PMID: 36298819 PMCID: PMC9607128 DOI: 10.3390/v14102264] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/12/2022] [Accepted: 10/13/2022] [Indexed: 11/27/2022] Open
Abstract
When human TDP-43 is overexpressed in yeast it is toxic and forms cytoplasmic aggregates. The mechanism of this toxicity is unknown. Genetic screens for TDP-43 toxicity modifiers in the yeast system previously identified proteins, including PBP1, that enhance TDP-43 toxicity. The determination in yeast that deletion of PBP1 reduces TDP-43 toxicity while overexpression enhances toxicity, led to the discovery that its human homolog, ATXN2, is associated with ALS risk. Thus, the yeast system has relevance to human disease. We now show that deletion of a new yeast gene, tip41Δ, likewise suppresses TDP-43 toxicity. We also found that TDP-43 overexpression and toxicity is associated with reduced autophagy. This is consistent with findings in other systems that increasing autophagy reduces TDP-43 toxicity and is in contrast to a report of enhanced autophagy when TDP-43 was overexpressed in yeast. Interestingly, we found that deletions of PBP1 and TIP41, which reduced TDP-43 toxicity, eliminated TDP-43's inhibition of autophagy. This suggests that toxicity of TDP-43 expressed in yeast is in part due to its inhibition of autophagy and that deletions of PBP1 and TIP41 may reduce TDP-43 toxicity by preventing TDP-43 from inhibiting autophagy.
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Affiliation(s)
| | | | - Susan W. Liebman
- Department of Pharmacology, University of Nevada, Reno, NV 89557, USA
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5
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Milicevic K, Rankovic B, Andjus PR, Bataveljic D, Milovanovic D. Emerging Roles for Phase Separation of RNA-Binding Proteins in Cellular Pathology of ALS. Front Cell Dev Biol 2022; 10:840256. [PMID: 35372329 PMCID: PMC8965147 DOI: 10.3389/fcell.2022.840256] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 01/24/2022] [Indexed: 12/11/2022] Open
Abstract
Liquid-liquid phase separation (LLPS) is emerging as a major principle for the mesoscale organization of proteins, RNAs, and membrane-bound organelles into biomolecular condensates. These condensates allow for rapid cellular responses to changes in metabolic activities and signaling. Nowhere is this regulation more important than in neurons and glia, where cellular physiology occurs simultaneously on a range of time- and length-scales. In a number of neurodegenerative diseases, such as Amyotrophic Lateral Sclerosis (ALS), misregulation of biomolecular condensates leads to the formation of insoluble aggregates—a pathological hallmark of both sporadic and familial ALS. Here, we summarize how the emerging knowledge about the LLPS of ALS-related proteins corroborates with their aggregation. Understanding the mechanisms that lead to protein aggregation in ALS and how cells respond to these aggregates promises to open new directions for drug development.
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Affiliation(s)
- Katarina Milicevic
- Center for Laser Microscopy, Faculty of Biology, Institute of Physiology and Biochemistry “Ivan Djaja”, University of Belgrade, Belgrade, Serbia
| | - Branislava Rankovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Pavle R. Andjus
- Center for Laser Microscopy, Faculty of Biology, Institute of Physiology and Biochemistry “Ivan Djaja”, University of Belgrade, Belgrade, Serbia
| | - Danijela Bataveljic
- Center for Laser Microscopy, Faculty of Biology, Institute of Physiology and Biochemistry “Ivan Djaja”, University of Belgrade, Belgrade, Serbia
- *Correspondence: Danijela Bataveljic, ; Dragomir Milovanovic,
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
- *Correspondence: Danijela Bataveljic, ; Dragomir Milovanovic,
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6
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Shevchuk DV, Abramova AA, Zakharova MN. The Role of Inflammasomes in the Pathogenesis of Neurodegenerative Diseases. NEUROCHEM J+ 2022; 16. [PMCID: PMC9575632 DOI: 10.1134/s1819712422030114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Abstract—Protein misfolding and accumulation of protein aggregates is a distinctive feature of most neurodegenerative diseases. They lead to disruption of cellular homeostasis, loss of synaptic connections, and therefore cellular apoptosis. It has been demonstrated that some innate immune responses play an important role in the emergence and progression of neurodegenerative diseases. Inflammasomes are components of innate immunity that play a major role in the maintenance of chronic inflammation. Inflammasomes function as intracellular sensors, detecting both exogenous and endogenous stimuli. They also take part in caspase-1 activation and the synthesis of pro-inflammatory cytokines. In the central nervous system (CNS), inflammasomes are predominantly expressed by microglia, the key cells of innate immunity responsible for activation and maintenance of inflammation. In addition to microglia, inflammasomes can be expressed and activated by astrocytes and neurons, as well as infiltrating myeloid cells. Understanding the mechanisms of activation and functioning of inflammasomes is crucial for the development of novel drugs targeted at modulation of the immune response associated with their excessive activation. This review provides up-to-date information on the inflammasome structure and mechanisms of action, the role of protein misfolding, aggregation and the influence of these factors on inflammasome activation, as well as potential therapeutic targets in neurodegenerative diseases.
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7
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Duran-Aniotz C, Orellana P, Leon Rodriguez T, Henriquez F, Cabello V, Aguirre-Pinto MF, Escobedo T, Takada LT, Pina-Escudero SD, Lopez O, Yokoyama JS, Ibanez A, Parra MA, Slachevsky A. Systematic Review: Genetic, Neuroimaging, and Fluids Biomarkers for Frontotemporal Dementia Across Latin America Countries. Front Neurol 2021; 12:663407. [PMID: 34248820 PMCID: PMC8263937 DOI: 10.3389/fneur.2021.663407] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 05/27/2021] [Indexed: 11/13/2022] Open
Abstract
Frontotemporal dementia (FTD) includes a group of clinically, genetically, and pathologically heterogeneous neurodegenerative disorders, affecting the fronto-insular-temporal regions of the brain. Clinically, FTD is characterized by progressive deficits in behavior, executive function, and language and its diagnosis relies mainly on the clinical expertise of the physician/consensus group and the use of neuropsychological tests and/or structural/functional neuroimaging, depending on local availability. The modest correlation between clinical findings and FTD neuropathology makes the diagnosis difficult using clinical criteria and often leads to underdiagnosis or misdiagnosis, primarily due to lack of recognition or awareness of FTD as a disease and symptom overlap with psychiatric disorders. Despite advances in understanding the underlying neuropathology of FTD, accurate and sensitive diagnosis for this disease is still lacking. One of the major challenges is to improve diagnosis in FTD patients as early as possible. In this context, biomarkers have emerged as useful methods to provide and/or complement clinical diagnosis for this complex syndrome, although more evidence is needed to incorporate most of them into clinical practice. However, most biomarker studies have been performed using North American or European populations, with little representation of the Latin American and the Caribbean (LAC) region. In the LAC region, there are additional challenges, particularly the lack of awareness and knowledge about FTD, even in specialists. Also, LAC genetic heritage and cultures are complex, and both likely influence clinical presentations and may modify baseline biomarker levels. Even more, due to diagnostic delay, the clinical presentation might be further complicated by both neurological and psychiatric comorbidity, such as vascular brain damage, substance abuse, mood disorders, among others. This systematic review provides a brief update and an overview of the current knowledge on genetic, neuroimaging, and fluid biomarkers for FTD in LAC countries. Our review highlights the need for extensive research on biomarkers in FTD in LAC to contribute to a more comprehensive understanding of the disease and its associated biomarkers. Dementia research is certainly reduced in the LAC region, highlighting an urgent need for harmonized, innovative, and cross-regional studies with a global perspective across multiple areas of dementia knowledge.
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Affiliation(s)
- Claudia Duran-Aniotz
- Latin American Institute for Brain Health (BrainLat), Universidad Adolfo Ibanez, Santiago, Chile
- Center for Social and Cognitive Neuroscience (CSCN), School of Psychology, Universidad Adolfo Ibanez, Santiago, Chile
| | - Paulina Orellana
- Latin American Institute for Brain Health (BrainLat), Universidad Adolfo Ibanez, Santiago, Chile
- Center for Social and Cognitive Neuroscience (CSCN), School of Psychology, Universidad Adolfo Ibanez, Santiago, Chile
| | - Tomas Leon Rodriguez
- Trinity College, Global Brain Health Institute, Dublin, Ireland
- Memory and Neuropsychiatric Clinic (CMYN) Neurology Department, Hospital del Salvador and Faculty of Medicine, University of Chile, Santiago, Chile
| | - Fernando Henriquez
- Neuropsychology and Clinical Neuroscience Laboratory (LANNEC), Physiopathology Department - Institute of Biomedical Sciences (ICBM), Neuroscience and East Neuroscience Departments, Faculty of Medicine, University of Chile, Santiago, Chile
- Geroscience Center for Brain Health and Metabolism (GERO), Santiago, Chile
| | - Victoria Cabello
- Neuropsychology and Clinical Neuroscience Laboratory (LANNEC), Physiopathology Department - Institute of Biomedical Sciences (ICBM), Neuroscience and East Neuroscience Departments, Faculty of Medicine, University of Chile, Santiago, Chile
- Geroscience Center for Brain Health and Metabolism (GERO), Santiago, Chile
| | | | - Tamara Escobedo
- Latin American Institute for Brain Health (BrainLat), Universidad Adolfo Ibanez, Santiago, Chile
- Center for Social and Cognitive Neuroscience (CSCN), School of Psychology, Universidad Adolfo Ibanez, Santiago, Chile
| | - Leonel T. Takada
- Cognitive and Behavioral Neurology Unit - Department of Neurology, University of São Paulo, São Paulo, Brazil
| | - Stefanie D. Pina-Escudero
- Global Brain Health Institute (GBHI), University of California San Francisco (UCSF), San Francisco, CA, United States
- UCSF Department of Neurology, Memory and Aging Center, UCSF, San Francisco, CA, United States
| | - Oscar Lopez
- Department of Neurology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jennifer S. Yokoyama
- Global Brain Health Institute (GBHI), University of California San Francisco (UCSF), San Francisco, CA, United States
- UCSF Department of Neurology, Memory and Aging Center, UCSF, San Francisco, CA, United States
| | - Agustin Ibanez
- Latin American Institute for Brain Health (BrainLat), Universidad Adolfo Ibanez, Santiago, Chile
- Center for Social and Cognitive Neuroscience (CSCN), School of Psychology, Universidad Adolfo Ibanez, Santiago, Chile
- Trinity College, Global Brain Health Institute, Dublin, Ireland
- Global Brain Health Institute (GBHI), University of California San Francisco (UCSF), San Francisco, CA, United States
- Cognitive Neuroscience Center (CNC), Universidad de San Andrés, & National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - Mario A. Parra
- School of Psychological Sciences and Health, University of Strathclyde, Glasgow, United Kingdom
| | - Andrea Slachevsky
- Memory and Neuropsychiatric Clinic (CMYN) Neurology Department, Hospital del Salvador and Faculty of Medicine, University of Chile, Santiago, Chile
- Neuropsychology and Clinical Neuroscience Laboratory (LANNEC), Physiopathology Department - Institute of Biomedical Sciences (ICBM), Neuroscience and East Neuroscience Departments, Faculty of Medicine, University of Chile, Santiago, Chile
- Geroscience Center for Brain Health and Metabolism (GERO), Santiago, Chile
- Cognitive and Behavioral Neurology Unit - Department of Neurology, University of São Paulo, São Paulo, Brazil
- Department of Neurology and Psychiatry, Clínica Alemana-Universidad del Desarrollo, Santiago, Chile
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8
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Leoni TB, González-Salazar C, Rezende TJR, Hernández ALC, Mattos AHB, Coimbra Neto AR, da Graça FF, Gonçalves JPN, Martinez ARM, Taniguti L, Kitajima JP, Kok F, Rogério F, da Silva AMS, de Oliveira ALR, Zanoteli E, Nucci A, França MC. A Novel Multisystem Proteinopathy Caused by a Missense ANXA11 Variant. Ann Neurol 2021; 90:239-252. [PMID: 34048612 DOI: 10.1002/ana.26136] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Protein misfolding plays a central role not only in amyotrophic lateral sclerosis (ALS), but also in other conditions, such as frontotemporal dementia (FTD), inclusion body myopathy (hIBM) or Paget's disease of bone. The concept of multisystem proteinopathies (MSP) was created to account for those rare families that segregate at least 2 out of these 4 conditions in the same pedigree. The calcium-dependent phospholipid-binding protein annexin A11 was recently associated to ALS in European pedigrees. Herein, we describe in detail 3 Brazilian families presenting hIBM (isolated or in combination with ALS/FTD) caused by the novel p.D40Y change in the gene encoding annexin A11 (ANXA11). METHODS We collected clinical, genetic, pathological and skeletal muscle imaging from 11 affected subjects. Neuroimaging was also obtained from 8 patients and 8 matched controls. RESULTS Clinico-radiological phenotype of this novel hIBM reveals a slowly progressive predominant limb-girdle syndrome, but with frequent axial (ptosis/dropped head) and distal (medial gastrocnemius) involvement as well. Muscle pathology identified numerous rimmed vacuoles with positive annexin A11, TDP-43 and p62 inclusions, but no inflammation. Central nervous system was also involved: two patients had FTD, but diffusion tensor imaging uncovered multiple areas of cerebral white matter damage in the whole group (including the corticospinal tracts and frontal subcortical regions). INTERPRETATION These findings expand the phenotypic spectrum related to ANXA11. This gene should be considered the cause of a novel multisystem proteinopathy (MSP type 6), rather than just ALS. ANN NEUROL 2021;90:239-252.
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Affiliation(s)
- Tauana Bernardes Leoni
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Carelis González-Salazar
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | | | - Ana Luisa C Hernández
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | | | | | - Felipe Franco da Graça
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | | | - Alberto R M Martinez
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | | | | | - Fernando Kok
- Mendelics Genomic Analyses, São Paulo, Brazil.,Department of Neurology, School of Medicine, University of São Paulo (USP), São Paulo, Brazil
| | - Fábio Rogério
- Department of Pathology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | | | | | - Edmar Zanoteli
- Department of Neurology, School of Medicine, University of São Paulo (USP), São Paulo, Brazil
| | - Anamarli Nucci
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Marcondes C França
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
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9
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Dominguez J, Yu JT, Tan YJ, Ng A, De Guzman MF, Natividad B, Daroy ML, Cano J, Yu J, Lian MM, Zeng L, Lim WK, Foo JN, Ng ASL. Novel Optineurin Frameshift Insertion in a Family With Frontotemporal Dementia and Parkinsonism Without Amyotrophic Lateral Sclerosis. Front Neurol 2021; 12:645913. [PMID: 34093394 PMCID: PMC8170397 DOI: 10.3389/fneur.2021.645913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/12/2021] [Indexed: 12/30/2022] Open
Abstract
Frontotemporal Dementia (FTD) is a common cause of Young Onset Dementia and has diverse clinical manifestations involving behavior, executive function, language and motor function, including parkinsonism. Up to 50% of FTD patients report a positive family history, supporting a strong genetic basis, particularly in cases with both FTD and amyotrophic lateral sclerosis (FTD-ALS). Mutations in three genes are associated with the majority of familial FTD (fFTD) cases - microtubule associated protein tau gene (MAPT), granulin precursor (GRN), and hexanucleotide repeat expansions in chromosome 9 open reading frame 72- SMCR8complex subunit (C9orf72) while mutations in other genes such as optineurin (OPTN) have rarely been reported. Mutations in OPTN have been reported mostly in familial and sporadic cases of ALS, or in rare cases of FTD-ALS, but not in association with pure or predominant FTD and/or parkinsonian phenotype. Here, we report for the first time, a family from the Philippines with four members harboring a novel frameshift insertion at OPTN (Chr 10:13166090 G>GA) p.Lys328GluTer11, three of whom presented with FTD-related phenotypes. Additionally, one sibling heterozygous for the frameshift insertion had a predominantly parkinsonian phenotype resembling corticobasal syndrome, but it remains to be determined if this phenotype is related to the frameshift insertion. Notably, none of the affected members showed any evidence of motor neuron disease or ALS at the time of writing, both clinically and on electrophysiological testing, expanding the phenotypic spectrum of OPTN mutations. Close follow-up of mutation carriers for the development of new clinical features and wider investigation of additional family members with further genetic analyses will be conducted to investigate the possibility of other genetic modifiers in this family which could explain phenotypic heterogeneity.
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Affiliation(s)
- Jacqueline Dominguez
- Institute for Neurosciences, St. Luke's Medical Center, Quezon City, Philippines
| | - Jeryl Tan Yu
- Institute for Neurosciences, St. Luke's Medical Center, Quezon City, Philippines
| | - Yi Jayne Tan
- Department of Neurology, National Neuroscience Institute, Singapore, Singapore
| | - Arlene Ng
- Institute for Neurosciences, St. Luke's Medical Center, Quezon City, Philippines
| | - Ma Fe De Guzman
- Research and Biotechnology Division, St Luke's Medical Centre, Quezon, Philippines
| | - Boots Natividad
- Research and Biotechnology Division, St Luke's Medical Centre, Quezon, Philippines
| | - Ma Luisa Daroy
- Research and Biotechnology Division, St Luke's Medical Centre, Quezon, Philippines
| | - Jemellee Cano
- Institute for Neurosciences, St. Luke's Medical Center, Quezon City, Philippines
| | - Justine Yu
- Institute for Neurosciences, St. Luke's Medical Center, Quezon City, Philippines
| | - Michelle M Lian
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Li Zeng
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, Singapore.,Neuroscience and Behavioural Disorders Programme, Duke-NUS Medical School, Singapore, Singapore
| | - Weng Khong Lim
- Singhealth Duke-NUS Institute of Precision Medicine, Singapore, Singapore.,Cancer & Stem Cell Biology Program, Duke-NUS Medical School, Singapore, Singapore
| | - Jia Nee Foo
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.,Human Genetics, Genome Institute of Singapore, ASTAR, Singapore, Singapore
| | - Adeline S L Ng
- Department of Neurology, National Neuroscience Institute, Singapore, Singapore.,Neuroscience and Behavioural Disorders Programme, Duke-NUS Medical School, Singapore, Singapore
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10
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van Rooij J, Mol MO, Melhem S, van der Wal P, Arp P, Paron F, Donker Kaat L, Seelaar H, Miedema SSM, Oshima T, Eggen BJL, Uitterlinden A, van Meurs J, van Kesteren RE, Smit AB, Buratti E, van Swieten JC. Somatic TARDBP variants as a cause of semantic dementia. Brain 2021; 143:3827-3841. [PMID: 33155043 PMCID: PMC7805802 DOI: 10.1093/brain/awaa317] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/13/2020] [Accepted: 08/06/2020] [Indexed: 12/12/2022] Open
Abstract
The aetiology of late-onset neurodegenerative diseases is largely unknown. Here we investigated whether de novo somatic variants for semantic dementia can be detected, thereby arguing for a more general role of somatic variants in neurodegenerative disease. Semantic dementia is characterized by a non-familial occurrence, early onset (<65 years), focal temporal atrophy and TDP-43 pathology. To test whether somatic variants in neural progenitor cells during brain development might lead to semantic dementia, we compared deep exome sequencing data of DNA derived from brain and blood of 16 semantic dementia cases. Somatic variants observed in brain tissue and absent in blood were validated using amplicon sequencing and digital PCR. We identified two variants in exon one of the TARDBP gene (L41F and R42H) at low level (1-3%) in cortical regions and in dentate gyrus in two semantic dementia brains, respectively. The pathogenicity of both variants is supported by demonstrating impaired splicing regulation of TDP-43 and by altered subcellular localization of the mutant TDP-43 protein. These findings indicate that somatic variants may cause semantic dementia as a non-hereditary neurodegenerative disease, which might be exemplary for other late-onset neurodegenerative disorders.
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Affiliation(s)
- Jeroen van Rooij
- Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Merel O Mol
- Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Shamiram Melhem
- Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Pelle van der Wal
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Pascal Arp
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Francesca Paron
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Laura Donker Kaat
- Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Harro Seelaar
- Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Suzanne S M Miedema
- Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, The Netherlands
| | - Takuya Oshima
- Department of Biomedical Sciences of Cells and Systems, section Molecular Neurobiology, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands
| | - Bart J L Eggen
- Department of Biomedical Sciences of Cells and Systems, section Molecular Neurobiology, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands
| | - André Uitterlinden
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Joyce van Meurs
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Ronald E van Kesteren
- Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, The Netherlands
| | - August B Smit
- Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, The Netherlands
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - John C van Swieten
- Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands
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11
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Ma P, Li Y, Wang H, Mao B. Haploinsufficiency of the TDP43 ubiquitin E3 ligase RNF220 leads to ALS-like motor neuron defects in the mouse. J Mol Cell Biol 2021; 13:374-382. [PMID: 33386850 PMCID: PMC8373269 DOI: 10.1093/jmcb/mjaa072] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 09/16/2020] [Accepted: 10/04/2020] [Indexed: 11/14/2022] Open
Abstract
TDP43 pathology is seen in a large majority of amyotrophic lateral sclerosis (ALS) cases, suggesting a central pathogenic role of this regulatory protein. Clarifying the molecular mechanism controlling TDP43 stability and subcellular location might provide important insights into ALS therapy. The ubiquitin E3 ligase RNF220 is involved in different neural developmental processes through various molecular targets in the mouse. Here, we report that the RNF220+/− mice showed progressively decreasing mobility to different extents, some of which developed typical ALS pathological characteristics in spinal motor neurons, including TDP43 cytoplasmic accumulation, atrocytosis, muscle denervation, and atrophy. Mechanistically, RNF220 interacts with TDP43 in vitro and in vivo and promotes its polyubiquitination and proteasomal degradation. In conclusion, we propose that RNF220 might be a modifier of TDP43 function in vivo and contribute to TDP43 pathology in neurodegenerative disease like ALS.
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Affiliation(s)
- Pengcheng Ma
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Yuwei Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, China
| | - Huishan Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, China
| | - Bingyu Mao
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, China
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12
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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: 50] [Impact Index Per Article: 12.5] [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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13
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Paez-Colasante X, Figueroa-Romero C, Rumora AE, Hur J, Mendelson FE, Hayes JM, Backus C, Taubman GF, Heinicke L, Walter NG, Barmada SJ, Sakowski SA, Feldman EL. Cytoplasmic TDP43 Binds microRNAs: New Disease Targets in Amyotrophic Lateral Sclerosis. Front Cell Neurosci 2020; 14:117. [PMID: 32477070 PMCID: PMC7235295 DOI: 10.3389/fncel.2020.00117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/14/2020] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive, fatal, and incurable neurodegenerative disease. Recent studies suggest that dysregulation of gene expression by microRNAs (miRNAs) may play an important role in ALS pathogenesis. The reversible nature of this dysregulation makes miRNAs attractive pharmacological targets and a potential therapeutic avenue. Under physiological conditions, miRNA biogenesis, which begins in the nucleus and includes further maturation in the cytoplasm, involves trans-activation response element DNA/RNA-binding protein of 43 kDa (TDP43). However, TDP43 mutations or stress trigger TDP43 mislocalization and inclusion formation, a hallmark of most ALS cases, that may lead to aberrant protein/miRNA interactions in the cytoplasm. Herein, we demonstrated that TDP43 exhibits differential binding affinity for select miRNAs, which prompted us to profile miRNAs that preferentially bind cytoplasmic TDP43. Using cellular models expressing TDP43 variants and miRNA profiling analyses, we identified differential levels of 65 cytoplasmic TDP43-associated miRNAs. Of these, approximately 30% exhibited levels that differed by more than 3-fold in the cytoplasmic TDP43 models relative to our control model. The hits included both novel miRNAs and miRNAs previously associated with ALS that potentially regulate several predicted genes and pathways that may be important for pathogenesis. Accordingly, these findings highlight specific miRNAs that may shed light on relevant disease pathways and could represent potential biomarkers and reversible treatment targets for ALS.
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Affiliation(s)
| | | | - Amy E. Rumora
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Junguk Hur
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States
| | - Faye E. Mendelson
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - John M. Hayes
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Carey Backus
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | | | - Laurie Heinicke
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI, United States
| | - Nils G. Walter
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI, United States
| | - Sami J. Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Stacey A. Sakowski
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Eva L. Feldman
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
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14
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Newell K, Paron F, Mompean M, Murrell J, Salis E, Stuani C, Pattee G, Romano M, Laurents D, Ghetti B, Buratti E. Dysregulation of TDP-43 intracellular localization and early onset ALS are associated with a TARDBP S375G variant. Brain Pathol 2018; 29:397-413. [PMID: 30461104 PMCID: PMC6875182 DOI: 10.1111/bpa.12680] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 11/12/2018] [Indexed: 02/06/2023] Open
Abstract
We investigated the Central Nervous System (CNS) and skeletal muscle tissue from A woman was clinically diagnosed with amyotrophic lateral sclerosis (ALS) at the age of 22. Neuropathologic evaluation showed upper and lower motor neuron loss, corticospinal tract degeneration and skeletal muscle denervation. Analysis of the patient's Deoxyribonucleic acid (DNA) revealed a AGT>GGT change resulting in an S375G substitution in the C-terminal region of TDP-43. This variant was previously reported as being benign. Considering the early onset and severity of the disease in this patient, we tested the effects of this genetic variant on TDP-43 localization, pre-mRNA splicing activity and toxicity, in parallel with the effects on known neighboring disease-associated mutations. In cell lines, expressed in culture, S375G TDP-43 appeared to be more significantly localized in the nucleus and to exert higher toxicity than wild-type TDP-43. Strikingly, a phosphomimic mutant at the same residue (S375E) showed a strong tendency to accumulate in the cytoplasm, especially under stress conditions, and molecular dynamics simulations suggest that phosphorylation of this residue can disrupt TDP-43 intermolecular interactions. The results of the current study highlight the importance of phosphorylation and regulation of TDP-43 nuclear-cytoplasmic shuttling/redistribution, in relation to the pathogenetic mechanisms involved in different forms of ALS.
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Affiliation(s)
- Kathy Newell
- University of Kansas School of Medicine, Pathology & Laboratory Medicine, Kansas City, MO
| | - Francesca Paron
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Miguel Mompean
- University of Castile-La Mancha, Instituto Regional de Investigación Científica Aplicada (IRICA), Ciudad Real, Spain
| | - Jill Murrell
- Indiana University School of Medicine, Pathology & Laboratory Medicine, Indianapolis, IN
| | - Elisa Salis
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Cristiana Stuani
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Gary Pattee
- University of Nebraska Medical Center, Lincoln, NE
| | - Maurizio Romano
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Douglas Laurents
- Instituto de Química Física "Rocasolano", Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Bernardino Ghetti
- Indiana University School of Medicine, Pathology & Laboratory Medicine, Indianapolis, IN
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
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15
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Sharkey LM, Safren N, Pithadia AS, Gerson JE, Dulchavsky M, Fischer S, Patel R, Lantis G, Ashraf N, Kim JH, Meliki A, Minakawa EN, Barmada SJ, Ivanova MI, Paulson HL. Mutant UBQLN2 promotes toxicity by modulating intrinsic self-assembly. Proc Natl Acad Sci U S A 2018; 115:E10495-E10504. [PMID: 30333186 PMCID: PMC6217421 DOI: 10.1073/pnas.1810522115] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
UBQLN2 is one of a family of proteins implicated in ubiquitin-dependent protein quality control and integrally tied to human neurodegenerative disease. Whereas wild-type UBQLN2 accumulates in intraneuronal deposits in several common age-related neurodegenerative diseases, mutations in the gene encoding this protein result in X-linked amyotrophic lateral sclerosis/frontotemporal dementia associated with TDP43 accumulation. Using in vitro protein analysis, longitudinal fluorescence imaging and cellular, neuronal, and transgenic mouse models, we establish that UBQLN2 is intrinsically prone to self-assemble into higher-order complexes, including liquid-like droplets and amyloid aggregates. UBQLN2 self-assembly and solubility are reciprocally modulated by the protein's ubiquitin-like and ubiquitin-associated domains. Moreover, a pathogenic UBQLN2 missense mutation impairs droplet dynamics and favors amyloid-like aggregation associated with neurotoxicity. These data emphasize the critical link between UBQLN2's role in ubiquitin-dependent pathways and its propensity to self-assemble and aggregate in neurodegenerative diseases.
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Affiliation(s)
- Lisa M Sharkey
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200
- Protein Folding Disease Initiative, University of Michigan, Ann Arbor, MI 48109-2200
| | - Nathaniel Safren
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200
| | - Amit S Pithadia
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200
| | - Julia E Gerson
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200
| | - Mark Dulchavsky
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200
| | - Svetlana Fischer
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200
| | - Ronak Patel
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200
| | - Gabrielle Lantis
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200
| | - Naila Ashraf
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200
| | - John H Kim
- Biophysics Program, University of Michigan, Ann Arbor, MI 48109-2200
| | - Alia Meliki
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200
| | - Eiko N Minakawa
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo 187-8502, Japan
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200;
- Protein Folding Disease Initiative, University of Michigan, Ann Arbor, MI 48109-2200
| | - Magdalena I Ivanova
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200;
- Protein Folding Disease Initiative, University of Michigan, Ann Arbor, MI 48109-2200
- Biophysics Program, University of Michigan, Ann Arbor, MI 48109-2200
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200;
- Protein Folding Disease Initiative, University of Michigan, Ann Arbor, MI 48109-2200
- Michigan Alzheimer's Disease Center, University of Michigan, Ann Arbor, MI 48109-2200
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16
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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: 49] [Impact Index Per Article: 8.2] [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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17
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TDP43 nuclear export and neurodegeneration in models of amyotrophic lateral sclerosis and frontotemporal dementia. Sci Rep 2018; 8:4606. [PMID: 29545601 PMCID: PMC5854632 DOI: 10.1038/s41598-018-22858-w] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 03/02/2018] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are progressive neurodegenerative disorders marked in most cases by the nuclear exclusion and cytoplasmic deposition of the RNA binding protein TDP43. We previously demonstrated that ALS-associated mutant TDP43 accumulates within the cytoplasm, and that TDP43 mislocalization predicts neurodegeneration. Here, we sought to prevent neurodegeneration in ALS/FTD models using selective inhibitor of nuclear export (SINE) compounds that target exportin-1 (XPO1). SINE compounds modestly extend cellular survival in neuronal ALS/FTD models and mitigate motor symptoms in an in vivo rat ALS model. At high doses, SINE compounds block nuclear egress of an XPO1 cargo reporter, but not at lower concentrations that were associated with neuroprotection. Neither SINE compounds nor leptomycin B, a separate XPO1 inhibitor, enhanced nuclear TDP43 levels, while depletion of XPO1 or other exportins had little effect on TDP43 localization, suggesting that no single exporter is necessary for TDP43 export. Supporting this hypothesis, we find overexpression of XPO1, XPO7 and NXF1 are each sufficient to promote nuclear TDP43 egress. Taken together, our results indicate that redundant pathways regulate TDP43 nuclear export, and that therapeutic prevention of cytoplasmic TDP43 accumulation in ALS/FTD may be enhanced by targeting several overlapping mechanisms.
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18
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Nan Y, Wang S, Jia W. Caspase independent cleavages of TDP-43 generates 35kD fragment that cause apoptosis of breast cancer cells. Biochem Biophys Res Commun 2018; 497:51-57. [PMID: 29421661 DOI: 10.1016/j.bbrc.2018.01.190] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 01/31/2018] [Indexed: 10/18/2022]
Abstract
Transactive response DNA-binding protein 43kD (TDP-43) is a major component of tau-negative and ubiquitin-positive inclusions that characterize ALS (amyotrophic lateral sclerosis) and FTLD (frontotemporal lobar degeneration). Due to its central role in neurodegenerative disease pathogenesis, most research recently has focused on its role associated with neurodegeneration disease, research on neuron and glial cell showed that pathological TDP-43 is associated with cell apoptosis which lead to loss of functional neurons and glial cells. However, little is known about its role on cancer cells, here we report a 35kD fragment of TDP-43 also plays a key role in apoptosis of breast cancer cells, and may be served as a potential therapeutic target to cure cancer.
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Affiliation(s)
- Yinan Nan
- International Department, China-Japan Friendship Hospital, Beijing, China
| | - Shaoqing Wang
- Traditional Chinese Medicine Department, Beijing Tiantan Hospital, Beijing, China
| | - William Jia
- Brain Research Centre, University of British Columbia, Vancouver, Canada.
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19
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Weskamp K, Barmada SJ. TDP43 and RNA instability in amyotrophic lateral sclerosis. Brain Res 2018; 1693:67-74. [PMID: 29395044 DOI: 10.1016/j.brainres.2018.01.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/09/2018] [Accepted: 01/12/2018] [Indexed: 12/13/2022]
Abstract
The nuclear RNA-binding protein TDP43 is integrally involved in RNA processing. In accord with this central function, TDP43 levels are tightly regulated through a negative feedback loop, in which TDP43 recognizes its own RNA transcript, destabilizes it, and reduces new TDP43 protein production. In the neurodegenerative disorder amyotrophic lateral sclerosis (ALS), cytoplasmic mislocalization and accumulation of TDP43 disrupt autoregulation; conversely, inefficient TDP43 autoregulation can lead to cytoplasmic TDP43 deposition and subsequent neurodegeneration. Because TDP43 plays a multifaceted role in maintaining RNA metabolism, its mislocalization and accumulation interrupt several RNA processing pathways that in turn affect RNA stability and gene expression. TDP43-mediated disruption of these pathways-including alternative mRNA splicing, non-coding RNA processing, and RNA granule dynamics-may directly or indirectly contribute to ALS pathogenesis. Therefore, strategies that restore effective TDP43 autoregulation may ultimately prevent neurodegeneration in ALS and related disorders.
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Affiliation(s)
- Kaitlin Weskamp
- Neuroscience Graduate Program and Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI, United States
| | - Sami J Barmada
- Neuroscience Graduate Program and Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI, United States.
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20
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Overexpression of the essential Sis1 chaperone reduces TDP-43 effects on toxicity and proteolysis. PLoS Genet 2017; 13:e1006805. [PMID: 28531192 PMCID: PMC5460882 DOI: 10.1371/journal.pgen.1006805] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 06/06/2017] [Accepted: 05/05/2017] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by selective loss of motor neurons with inclusions frequently containing the RNA/DNA binding protein TDP-43. Using a yeast model of ALS exhibiting TDP-43 dependent toxicity, we now show that TDP-43 overexpression dramatically alters cell shape and reduces ubiquitin dependent proteolysis of a reporter construct. Furthermore, we show that an excess of the Hsp40 chaperone, Sis1, reduced TDP-43’s effect on toxicity, cell shape and proteolysis. The strength of these effects was influenced by the presence of the endogenous yeast prion, [PIN+]. Although overexpression of Sis1 altered the TDP-43 aggregation pattern, we did not detect physical association of Sis1 with TDP-43, suggesting the possibility of indirect effects on TDP-43 aggregation. Furthermore, overexpression of the mammalian Sis1 homologue, DNAJB1, relieves TDP-43 mediated toxicity in primary rodent cortical neurons, suggesting that Sis1 and its homologues may have neuroprotective effects in ALS. Many neurodegenerative diseases are associated with aggregation of specific proteins. Thus we are interested in factors that influence the aggregation and how the aggregated proteins are associated with pathology. Here, we study a protein called TDP-43 that is frequently aggregated in the neurons of patients with amyotrophic lateral sclerosis (ALS). TDP-43 aggregates and is toxic when expressed in yeast, providing a useful model for ALS. Remarkably, a protein that modified TDP-43 toxicity in yeast successfully predicted a new ALS susceptibility gene in humans. We now report a new modifier of TDP-43 toxicity, Sis1. We show that expression of TDP-43 in yeast inhibits degradation of damaged protein, while overexpression of Sis1 restores degradation. Thus suggests a link between protein degradation and TDP-43 toxicity. Furthermore we show that a mammalian protein similar to Sis1 reduces TDP-43 toxicity in primary rodent neurons. This identifies the mammalian Sis1-like gene as a new ALS therapeutic target and possible susceptibility gene.
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21
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Bhandare VV, Ramaswamy A. The proteinopathy of D169G and K263E mutants at the RNA Recognition Motif (RRM) domain of tar DNA-binding protein (tdp43) causing neurological disorders: A computational study. J Biomol Struct Dyn 2017; 36:1075-1093. [DOI: 10.1080/07391102.2017.1310670] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
| | - Amutha Ramaswamy
- Centre for Bioinformatics, Pondicherry University, Pondicherry 605014, India
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22
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Chiang CH, Grauffel C, Wu LS, Kuo PH, Doudeva LG, Lim C, Shen CKJ, Yuan HS. Structural analysis of disease-related TDP-43 D169G mutation: linking enhanced stability and caspase cleavage efficiency to protein accumulation. Sci Rep 2016; 6:21581. [PMID: 26883171 PMCID: PMC4756693 DOI: 10.1038/srep21581] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 01/25/2016] [Indexed: 12/12/2022] Open
Abstract
The RNA-binding protein TDP-43 forms intracellular inclusions in amyotrophic lateral sclerosis (ALS). While TDP-43 mutations have been identified in ALS patients, how these mutations are linked to ALS remains unclear. Here we examined the biophysical properties of six ALS-linked TDP-43 mutants and found that one of the mutants, D169G, had higher thermal stability than wild-type TDP-43 and that it was cleaved by caspase 3 more efficiently, producing increased levels of the C-terminal 35 kD fragments (TDP-35) in vitro and in neuroblastoma cells. The crystal structure of the TDP-43 RRM1 domain containing the D169G mutation in complex with DNA along with molecular dynamics simulations reveal that the D169G mutation induces a local conformational change in a β turn and increases the hydrophobic interactions in the RRM1 core, thus enhancing the thermal stability of the RRM1 domain. Our results provide the first crystal structure of TDP-43 containing a disease-linked D169G mutation and a disease-related mechanism showing that D169G mutant is more susceptible to proteolytic cleavage by caspase 3 into the pathogenic C-terminal 35-kD fragments due to its increased stability in the RRM1 domain. Modulation of TDP-43 stability and caspase cleavage efficiency could present an avenue for prevention and treatment of TDP-43-linked neurodegeneration.
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Affiliation(s)
- Chien-Hao Chiang
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan.,Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsin Chu, 30013, Taiwan
| | - Cédric Grauffel
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan
| | - Lien-Szu Wu
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Pan-Hsien Kuo
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
| | | | - Carmay Lim
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan
| | | | - Hanna S Yuan
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
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Tang AY. RNA processing-associated molecular mechanisms of neurodegenerative diseases. J Appl Genet 2015; 57:323-33. [DOI: 10.1007/s13353-015-0330-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 11/22/2015] [Accepted: 11/26/2015] [Indexed: 12/13/2022]
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Amelioration of toxicity in neuronal models of amyotrophic lateral sclerosis by hUPF1. Proc Natl Acad Sci U S A 2015; 112:7821-6. [PMID: 26056265 DOI: 10.1073/pnas.1509744112] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Over 30% of patients with amyotrophic lateral sclerosis (ALS) exhibit cognitive deficits indicative of frontotemporal dementia (FTD), suggesting a common pathogenesis for both diseases. Consistent with this hypothesis, neuronal and glial inclusions rich in TDP43, an essential RNA-binding protein, are found in the majority of those with ALS and FTD, and mutations in TDP43 and a related RNA-binding protein, FUS, cause familial ALS and FTD. TDP43 and FUS affect the splicing of thousands of transcripts, in some cases triggering nonsense-mediated mRNA decay (NMD), a highly conserved RNA degradation pathway. Here, we take advantage of a faithful primary neuronal model of ALS and FTD to investigate and characterize the role of human up-frameshift protein 1 (hUPF1), an RNA helicase and master regulator of NMD, in these disorders. We show that hUPF1 significantly protects mammalian neurons from both TDP43- and FUS-related toxicity. Expression of hUPF2, another essential component of NMD, also improves survival, whereas inhibiting NMD prevents rescue by hUPF1, suggesting that hUPF1 acts through NMD to enhance survival. These studies emphasize the importance of RNA metabolism in ALS and FTD, and identify a uniquely effective therapeutic strategy for these disorders.
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Abstract
The degeneration of motor neurons in amyotrophic lateral sclerosis (ALS) inevitably causes paralysis and death within a matter of years. Mounting genetic and functional evidence suggest that abnormalities in RNA processing and metabolism underlie motor neuron loss in sporadic and familial ALS. Abnormal localization and aggregation of essential RNA-binding proteins are fundamental pathological features of sporadic ALS, and mutations in genes encoding RNA processing enzymes cause familial disease. Also, expansion mutations occurring in the noncoding region of C9orf72-the most common cause of inherited ALS-result in nuclear RNA foci, underscoring the link between abnormal RNA metabolism and neurodegeneration in ALS. This review summarizes the current understanding of RNA dysfunction in ALS, and builds upon this knowledge base to identify converging mechanisms of neurodegeneration in ALS. Potential targets for therapy development are highlighted, with particular emphasis on early and conserved pathways that lead to motor neuron loss in ALS.
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Affiliation(s)
- Sami J Barmada
- Department of Neurology, University of Michigan, 109 Zina Pitcher Place, 5015 Biomedical Sciences Research Building, SSPC 2200, Ann Arbor, MI, 48109, USA,
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26
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Buratti E. Functional Significance of TDP-43 Mutations in Disease. ADVANCES IN GENETICS 2015; 91:1-53. [DOI: 10.1016/bs.adgen.2015.07.001] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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27
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Barmada SJ, Serio A, Arjun A, Bilican B, Daub A, Ando DM, Tsvetkov A, Pleiss M, Li X, Peisach D, Shaw C, Chandran S, Finkbeiner S. Autophagy induction enhances TDP43 turnover and survival in neuronal ALS models. Nat Chem Biol 2014; 10:677-85. [PMID: 24974230 PMCID: PMC4106236 DOI: 10.1038/nchembio.1563] [Citation(s) in RCA: 331] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 05/19/2014] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) have distinct clinical features but a common pathology—cytoplasmic inclusions rich in TDP43. Rare TDP43 mutations cause ALS or FTD, but abnormal TDP43 levels and localization may cause disease even if TDP43 lacks a mutation. Here we showed that individual neurons vary in their ability to clear TDP43 and are exquisitely sensitive to TDP43 levels. To measure TDP43 clearance, we developed and validated a single-cell optical method that overcomes the confounding effects of aggregation and toxicity, and discovered that pathogenic mutations significantly shorten TDP43 half-life. Novel compounds that stimulate autophagy improved TDP43 clearance and localization, and enhanced survival in primary murine neurons and in human stem cell–derived neurons and astrocytes harboring mutant TDP43. These findings indicate that the levels and localization of TDP43 critically determine neurotoxicity and show that autophagy induction mitigates neurodegeneration by acting directly on TDP43 clearance.
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Affiliation(s)
- Sami J Barmada
- 1] Gladstone Institute of Neurologic Disease, San Francisco, California, USA. [2] Department of Neurology, University of California-San Francisco Medical Center, San Francisco, California, USA. [3] Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Andrea Serio
- 1] Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Scotland, UK. [2] Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, Scotland, UK. [3] Departments of Materials and Bioengineering, and Institute for Biomedical Engineering, Imperial College, London, UK
| | - Arpana Arjun
- Gladstone Institute of Neurologic Disease, San Francisco, California, USA
| | - Bilada Bilican
- 1] Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Scotland, UK. [2] Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, Scotland, UK
| | - Aaron Daub
- Gladstone Institute of Neurologic Disease, San Francisco, California, USA
| | - D Michael Ando
- 1] Gladstone Institute of Neurologic Disease, San Francisco, California, USA. [2] Biomedical Sciences Graduate Program, University of California-San Francisco, San Francisco, California, USA
| | - Andrey Tsvetkov
- 1] Gladstone Institute of Neurologic Disease, San Francisco, California, USA. [2] Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, Texas, USA
| | - Michael Pleiss
- Keck Program in Brain Cell Engineering, Gladstone Institutes, San Francisco, California, USA
| | - Xingli Li
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Daniel Peisach
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Siddharthan Chandran
- 1] Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Scotland, UK. [2] Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, Scotland, UK
| | - Steven Finkbeiner
- 1] Gladstone Institute of Neurologic Disease, San Francisco, California, USA. [2] Department of Neurology, University of California-San Francisco Medical Center, San Francisco, California, USA. [3] Biomedical Sciences Graduate Program, University of California-San Francisco, San Francisco, California, USA. [4] Keck Program in Brain Cell Engineering, Gladstone Institutes, San Francisco, California, USA. [5] Department of Physiology, University of California-San Francisco, San Francisco, California, USA. [6] Taube-Koret Center for Neurodegenerative Disease Research, San Francisco, California, USA. [7] Hellman Family Foundation Alzheimer's Disease Research Program, San Francisco, California, USA. [8] Roddenberry Stem Cell Program, San Francisco, California, USA
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28
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Dysregulated microRNAs in amyotrophic lateral sclerosis microglia modulate genes linked to neuroinflammation. Cell Death Dis 2013; 4:e959. [PMID: 24336079 PMCID: PMC3877562 DOI: 10.1038/cddis.2013.491] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 11/07/2013] [Accepted: 11/08/2013] [Indexed: 12/22/2022]
Abstract
MicroRNAs (miRNAs) regulate gene expression at post-transcriptional level and are key modulators of immune system, whose dysfunction contributes to the progression of neuroinflammatory diseaseas such as amyotrophic lateral sclerosis (ALS), the most widespread motor neuron disorder. ALS is a non-cell-autonomous disease targeting motor neurons and neighboring glia, with microgliosis directly contributing to neurodegeneration. As limited information exists on miRNAs dysregulations in ALS, we examined this topic in primary microglia from superoxide dismutase 1-G93A mouse model. We compared miRNAs transcriptional profiling of non-transgenic and ALS microglia in resting conditions and after inflammatory activation by P2X7 receptor agonist. We identified upregulation of selected immune-enriched miRNAs, recognizing miR-22, miR-155, miR-125b and miR-146b among the most highly modulated. We proved that miR-365 and miR-125b interfere, respectively, with the interleukin-6 and STAT3 pathway determining increased tumor necrosis factor alpha (TNFα) transcription. As TNFα directly upregulated miR-125b, and inhibitors of miR-365/miR-125b reduced TNFα transcription, we recognized the induction of miR-365 and miR-125b as a vicious gateway culminating in abnormal TNFα release. These results strengthen the impact of miRNAs in modulating inflammatory genes linked to ALS and identify specific miRNAs as pathogenetic mechanisms in the disease.
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29
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Kobeleva X, Petri S. Barriers to novel therapeutics in amyotrophic lateral sclerosis. Neurodegener Dis Manag 2013. [DOI: 10.2217/nmt.13.66] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SUMMARY Amyotrophic lateral sclerosis is a devastating neurodegenerative condition primarily involving the motor system in the cerebral cortex, brain stem and spinal cord, but can, in later disease stages, also affect distinct extramotor brain regions. In this article, we discuss the prevalent barriers, including clinical and genetic variability of amyotrophic lateral sclerosis, frailty of the current mouse model and inadequateness of clinical trials, in the search for novel therapeutics. Approaches in terms of understanding the pathogenesis, and the search for biomarkers to initiate early or even presymptomatic treatment and monitor treatment effects are highlighted.
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Affiliation(s)
- Xenia Kobeleva
- Department of Neurology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Susanne Petri
- Department of Neurology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
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30
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Moujalled D, James JL, Parker SJ, Lidgerwood GE, Duncan C, Meyerowitz J, Nonaka T, Hasegawa M, Kanninen KM, Grubman A, Liddell JR, Crouch PJ, White AR. Kinase Inhibitor Screening Identifies Cyclin-Dependent Kinases and Glycogen Synthase Kinase 3 as Potential Modulators of TDP-43 Cytosolic Accumulation during Cell Stress. PLoS One 2013; 8:e67433. [PMID: 23840699 PMCID: PMC3694067 DOI: 10.1371/journal.pone.0067433] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 05/21/2013] [Indexed: 12/13/2022] Open
Abstract
Abnormal processing of TAR DNA binding protein 43 (TDP-43) has been identified as a major factor in neuronal degeneration during amyotrophic lateral sclerosis (ALS) or frontotemporal lobar degeneration (FTLD). It is unclear how changes to TDP-43, including nuclear to cytosolic translocation and subsequent accumulation, are controlled in these diseases. TDP-43 is a member of the heterogeneous ribonucleoprotein (hnRNP) RNA binding protein family and is known to associate with cytosolic RNA stress granule proteins in ALS and FTLD. hnRNP trafficking and accumulation is controlled by the action of specific kinases including members of the mitogen-activated protein kinase (MAPK) pathway. However, little is known about how kinase pathways control TDP-43 movement and accumulation. In this study, we used an in vitro model of TDP-43-positve stress granule formation to screen for the effect of kinase inhibitors on TDP-43 accumulation. We found that while a number of kinase inhibitors, particularly of the MAPK pathways modulated both TDP-43 and the global stress granule marker, human antigen R (HuR), multiple inhibitors were more specific to TDP-43 accumulation, including inhibitors of cyclin-dependent kinases (CDKs) and glycogen synthase kinase 3 (GSK3). Close correlation was observed between effects of these inhibitors on TDP-43, hnRNP K and TIAR, but often with different effects on HuR accumulation. This may indicate a potential interaction between TDP-43, hnRNP K and TIAR. CDK inhibitors were also found to reverse pre-formed TDP-43-positive stress granules and both CDK and GSK3 inhibitors abrogated the accumulation of C-terminal TDP-43 (219–414) in transfected cells. Further studies are required to confirm the specific kinases involved and whether their action is through phosphorylation of the TDP-43 binding partner hnRNP K. This knowledge provides a valuable insight into the mechanisms controlling abnormal cytoplasmic TDP-43 accumulation and may herald new opportunities for kinase modulation-based therapeutic intervention in ALS and FTLD.
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Affiliation(s)
- Diane Moujalled
- Department of Pathology, The University of Melbourne, Victoria, Australia and Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Janine L. James
- Department of Pathology, The University of Melbourne, Victoria, Australia and Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Sarah J. Parker
- Department of Pathology, The University of Melbourne, Victoria, Australia and Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Grace E. Lidgerwood
- Department of Pathology, The University of Melbourne, Victoria, Australia and Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Clare Duncan
- Department of Pathology, The University of Melbourne, Victoria, Australia and Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Jodi Meyerowitz
- Department of Pathology, The University of Melbourne, Victoria, Australia and Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Takashi Nonaka
- Department of Neuropathology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan
| | - Masato Hasegawa
- Department of Neuropathology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan
| | - Katja M. Kanninen
- A.I. Virtanen Institute for Molecular Sciences, Laboratory of Molecular Brain Research, University of Eastern Finland, Kuopio, Finland
| | - Alexandra Grubman
- Department of Pathology, The University of Melbourne, Victoria, Australia and Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Jeffrey R. Liddell
- Department of Pathology, The University of Melbourne, Victoria, Australia and Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Peter J. Crouch
- Department of Pathology, The University of Melbourne, Victoria, Australia and Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Anthony R. White
- Department of Pathology, The University of Melbourne, Victoria, Australia and Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
- * E-mail:
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31
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Jiang LL, Che MX, Zhao J, Zhou CJ, Xie MY, Li HY, He JH, Hu HY. Structural transformation of the amyloidogenic core region of TDP-43 protein initiates its aggregation and cytoplasmic inclusion. J Biol Chem 2013; 288:19614-24. [PMID: 23689371 DOI: 10.1074/jbc.m113.463828] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
TDP-43 (TAR DNA-binding protein of 43 kDa) is a major deposited protein in amyotrophic lateral sclerosis and frontotemporal dementia with ubiquitin. A great number of genetic mutations identified in the flexible C-terminal region are associated with disease pathologies. We investigated the molecular determinants of TDP-43 aggregation and its underlying mechanisms. We identified a hydrophobic patch (residues 318-343) as the amyloidogenic core essential for TDP-43 aggregation. Biophysical studies demonstrated that the homologous peptide formed a helix-turn-helix structure in solution, whereas it underwent structural transformation from an α-helix to a β-sheet during aggregation. Mutation or deletion of this core region significantly reduced the aggregation and cytoplasmic inclusions of full-length TDP-43 (or TDP-35 fragment) in cells. Thus, structural transformation of the amyloidogenic core initiates the aggregation and cytoplasmic inclusion formation of TDP-43. This particular core region provides a potential therapeutic target to design small-molecule compounds for mitigating TDP-43 proteinopathies.
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Affiliation(s)
- Lei-Lei Jiang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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32
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Bhardwaj A, Myers MP, Buratti E, Baralle FE. Characterizing TDP-43 interaction with its RNA targets. Nucleic Acids Res 2013; 41:5062-74. [PMID: 23519609 PMCID: PMC3643599 DOI: 10.1093/nar/gkt189] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
One of the most important functional features of nuclear factor TDP-43 is its ability to bind UG-repeats with high efficiency. Several cross-linking and immunoprecipitation (CLIP) and RNA immunoprecipitation-sequencing (RIP-seq) analyses have indicated that TDP-43 in vivo can also specifically bind loosely conserved UG/GU-rich repeats interspersed by other nucleotides. These sequences are predominantly localized within long introns and in the 3′UTR of various genes. Most importantly, some of these sequences have been found to exist in the 3′UTR region of TDP-43 itself. In the TDP-43 3′UTR context, the presence of these UG-like sequences is essential for TDP-43 to autoregulate its own levels through a negative feedback loop. In this work, we have compared the binding of TDP-43 with these types of sequences as opposed to perfect UG-stretches. We show that the binding affinity to the UG-like sequences has a dissociation constant (Kd) of ∼110 nM compared with a Kd of 8 nM for straight UGs, and have mapped the region of contact between protein and RNA. In addition, our results indicate that the local concentration of UG dinucleotides in the CLIP sequences is one of the major factors influencing the interaction of these RNA sequences with TDP-43.
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Affiliation(s)
- Amit Bhardwaj
- International Centre for Genetic Engineering and Biotechnology (ICGEB), 34012 Trieste, Italy
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33
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Roberson ED. Mouse models of frontotemporal dementia. Ann Neurol 2013; 72:837-49. [PMID: 23280835 DOI: 10.1002/ana.23722] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 07/05/2012] [Accepted: 07/30/2012] [Indexed: 12/14/2022]
Abstract
The pace of discovery in frontotemporal dementia (FTD) has accelerated dramatically with the discovery of new genetic causes and pathological substrates of the disease. MAPT/tau, GRN/progranulin, and C9ORF72 have emerged as common FTD genes, and TARDBP/TDP-43, VCP, FUS, and CHMP2B have been identified as less common genetic causes. TDP-43 and FUS have joined tau as common neuropathological substrates of the disease. Mouse models provide an important tool for understanding the role of these molecules in FTD pathogenesis. Here, we review recent progress with mouse models based on tau, TDP-43, progranulin, VCP, and CHMP2B. We also consider future prospects for FTD models, including developing new models to address unanswered questions. There are also opportunities for capitalizing on conservation of the salience network, which is selectively vulnerable in FTD, and the availability of FTD-related behavioral paradigms to analyze mouse models of the disease.
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Affiliation(s)
- Erik D Roberson
- Departments of Neurology and Neurobiology, Center for Neurodegeneration and Experimental Therapeutics, University of Alabama, Birmingham, AL 35294, USA.
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34
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Youmans KL, Wolozin B. TDP-43: a new player on the AD field? Exp Neurol 2012; 237:90-5. [PMID: 22691390 DOI: 10.1016/j.expneurol.2012.05.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 05/17/2012] [Accepted: 05/27/2012] [Indexed: 12/20/2022]
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35
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Yu Z, Fan D, Gui B, Shi L, Xuan C, Shan L, Wang Q, Shang Y, Wang Y. Neurodegeneration-associated TDP-43 interacts with fragile X mental retardation protein (FMRP)/Staufen (STAU1) and regulates SIRT1 expression in neuronal cells. J Biol Chem 2012; 287:22560-72. [PMID: 22584570 DOI: 10.1074/jbc.m112.357582] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Despite the identification of the 43 kDa transactive response DNA-binding protein (TDP-43) as a major pathological signatory protein in a wide range of neurodegenerative diseases, the mechanistic role of TDP-43 in neurodegenerative disorders is still poorly understood. Here, we report that TDP-43 is physically associated with fragile X mental retardation protein (FMRP) and Staufen (STAU1) to form a functional complex. Differential microarray analysis revealed that the expression of a collection of functionally important genes including Sirtuin (SIRT1) is regulated by this complex. RNA-immunoprecipitation (RIP) and RNA pull-down assays demonstrated that TDP-43/FMRP/STAU1 specifically binds to the 3'-UTR of SIRT1 mRNA, and that knockdown the expression of any one of these three proteins resulted in the reduction of SIRT1 mRNA and protein. SIRT1 is implicated in double-stranded DNA break repair and is required for cell survival. Indeed, depletion of TDP-43/FMRP/STAU1 sensitizes cells to apoptosis and DNA damages. Collectively, our results revealed a molecular mechanism for the cellular function of TDP-43 and might shed new light on the understanding of the mechanistic role of TDP-43 in neurodegenerative diseases.
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Affiliation(s)
- Zhipeng Yu
- The Third Hospital, Peking University, Beijing 100191, China
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36
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Budini M, Romano V, Avendaño-Vázquez SE, Bembich S, Buratti E, Baralle FE. Role of selected mutations in the Q/N rich region of TDP-43 in EGFP-12xQ/N-induced aggregate formation. Brain Res 2012; 1462:139-50. [PMID: 22406069 DOI: 10.1016/j.brainres.2012.02.031] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 02/02/2012] [Accepted: 02/03/2012] [Indexed: 02/08/2023]
Abstract
The overview of TDP 43 functions immediately disclose a number of open questions regarding its pathological role. The formation of TDP-43 aggregates is one of the major distinguishing features of TDP-43 proteinopathies, especially in patients affected by Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Lobar degeneration (FTLD). At the moment, however, very little is known regarding the biological processes that underlie TDP-43 aggregation and, most importantly, its potential consequences on cellular metabolism. For these reasons, it is particularly important to further investigate this process in order to gain a better understanding of the pathology and to develop novel therapeutic effectors. In this report, we focus on a series of missense mutations associated with disease in the 342-366 region of this protein to examine their ability to affect RNA splicing regulation and to induce aggregate formation. In particular, aggregate formation was assessed in a novel system capable of inducing TDP-43 aggregation in experimental cell lines and primary neuronal cultures. The results of this analysis showed that the presence of two of these missense mutations in the 342-366 region (G348V and N352S) could differentially affect the levels and appearance of TDP-43 aggregation with respect to the wild-type protein. This article is part of a Special Issue entitled RNA-Binding Proteins.
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Affiliation(s)
- Mauricio Budini
- International Centre for Genetic Engineering and Biotechnology (ICGEB) 34012 Trieste, Italy
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37
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Postel-Vinay S, Véron AS, Tirode F, Pierron G, Reynaud S, Kovar H, Oberlin O, Lapouble E, Ballet S, Lucchesi C, Kontny U, González-Neira A, Picci P, Alonso J, Patino-Garcia A, de Paillerets BB, Laud K, Dina C, Froguel P, Clavel-Chapelon F, Doz F, Michon J, Chanock SJ, Thomas G, Cox DG, Delattre O. Common variants near TARDBP and EGR2 are associated with susceptibility to Ewing sarcoma. Nat Genet 2012; 44:323-7. [PMID: 22327514 DOI: 10.1038/ng.1085] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 12/22/2011] [Indexed: 01/23/2023]
Abstract
Ewing sarcoma, a pediatric tumor characterized by EWSR1-ETS fusions, is predominantly observed in populations of European ancestry. We performed a genome-wide association study (GWAS) of 401 French individuals with Ewing sarcoma, 684 unaffected French individuals and 3,668 unaffected individuals of European descent and living in the United States. We identified candidate risk loci at 1p36.22, 10q21 and 15q15. We replicated these loci in two independent sets of cases and controls. Joint analysis identified associations with rs9430161 (P = 1.4 × 10(-20); odds ratio (OR) = 2.2) located 25 kb upstream of TARDBP, rs224278 (P = 4.0 × 10(-17); OR = 1.7) located 5 kb upstream of EGR2 and, to a lesser extent, rs4924410 at 15q15 (P = 6.6 × 10(-9); OR = 1.5). The major risk haplotypes were less prevalent in Africans, suggesting that these loci could contribute to geographical differences in Ewing sarcoma incidence. TARDBP shares structural similarities with EWSR1 and FUS, which encode RNA binding proteins, and EGR2 is a target gene of EWSR1-ETS. Variants at these loci were associated with expression levels of TARDBP, ADO (encoding cysteamine dioxygenase) and EGR2.
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38
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Budini M, Buratti E, Stuani C, Guarnaccia C, Romano V, De Conti L, Baralle FE. Cellular model of TAR DNA-binding protein 43 (TDP-43) aggregation based on its C-terminal Gln/Asn-rich region. J Biol Chem 2012; 287:7512-25. [PMID: 22235134 DOI: 10.1074/jbc.m111.288720] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
TDP-43 is one of the major components of the neuronal and glial inclusions observed in several neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration. These characteristic aggregates are a "landmark" of the disease, but their role in the pathogenesis is still obscure. In previous works, we have shown that the C-terminal Gln/Asn-rich region (residues 321-366) of TDP-43 is involved in the interaction of this protein with other members of the heterogeneous nuclear ribonucleoprotein protein family. Furthermore, we have shown that the interaction through this region is important for TDP-43 splicing inhibition of cystic fibrosis transmembrane regulator exon 9, and there were indications that it was involved in the aggregation process. Our experiments show that in cell lines and primary rat neuronal cultures, the introduction of tandem repeats carrying the 331-369-residue Gln/Asn region from TDP-43 can trigger the formation of phosphorylated and ubiquitinated aggregates that recapitulate many but not all the characteristics observed in patients. These results establish a much needed cell-based TDP-43 aggregation model useful to investigate the mechanisms involved in the formation of inclusions and the gain- and loss-of-function consequences of TDP-43 aggregation within cells. In addition, it will be a powerful tool to test novel therapeutic strategies/effectors aimed at preventing/reducing this phenomenon.
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Affiliation(s)
- Mauricio Budini
- International Centre for Genetic Engineering and Biotechnology, 34012 Trieste, Italy
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39
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Buratti E, Baralle FE. TDP-43: new aspects of autoregulation mechanisms in RNA binding proteins and their connection with human disease. FEBS J 2011; 278:3530-8. [DOI: 10.1111/j.1742-4658.2011.08257.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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40
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Meyerowitz J, Parker SJ, Vella LJ, Ng DC, Price KA, Liddell JR, Caragounis A, Li QX, Masters CL, Nonaka T, Hasegawa M, Bogoyevitch MA, Kanninen KM, Crouch PJ, White AR. C-Jun N-terminal kinase controls TDP-43 accumulation in stress granules induced by oxidative stress. Mol Neurodegener 2011; 6:57. [PMID: 21819629 PMCID: PMC3162576 DOI: 10.1186/1750-1326-6-57] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 08/08/2011] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND TDP-43 proteinopathies are characterized by loss of nuclear TDP-43 expression and formation of C-terminal TDP-43 fragmentation and accumulation in the cytoplasm. Recent studies have shown that TDP-43 can accumulate in RNA stress granules (SGs) in response to cell stresses and this could be associated with subsequent formation of TDP-43 ubiquinated protein aggregates. However, the initial mechanisms controlling endogenous TDP-43 accumulation in SGs during chronic disease are not understood. In this study we investigated the mechanism of TDP-43 processing and accumulation in SGs in SH-SY5Y neuronal-like cells exposed to chronic oxidative stress. Cell cultures were treated overnight with the mitochondrial inhibitor paraquat and examined for TDP-43 and SG processing. RESULTS We found that mild stress induced by paraquat led to formation of TDP-43 and HuR-positive SGs, a proportion of which were ubiquitinated. The co-localization of TDP-43 with SGs could be fully prevented by inhibition of c-Jun N-terminal kinase (JNK). JNK inhibition did not prevent formation of HuR-positive SGs and did not prevent diffuse TDP-43 accumulation in the cytosol. In contrast, ERK or p38 inhibition prevented formation of both TDP-43 and HuR-positive SGs. JNK inhibition also inhibited TDP-43 SG localization in cells acutely treated with sodium arsenite and reduced the number of aggregates per cell in cultures transfected with C-terminal TDP-43 162-414 and 219-414 constructs. CONCLUSIONS Our studies are the first to demonstrate a critical role for kinase control of TDP-43 accumulation in SGs and may have important implications for development of treatments for FTD and ALS, targeting cell signal pathway control of TDP-43 aggregation.
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Affiliation(s)
- Jodi Meyerowitz
- Department of Pathology, The University of Melbourne, Victoria, 3010, Australia.
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41
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TDP-43 functions and pathogenic mechanisms implicated in TDP-43 proteinopathies. Trends Mol Med 2011; 17:659-67. [PMID: 21783422 DOI: 10.1016/j.molmed.2011.06.004] [Citation(s) in RCA: 167] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 06/20/2011] [Indexed: 12/13/2022]
Abstract
Given the critical role for TDP-43 in diverse neurodegenerative diseases including amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD-TDP), there has been a recent surge in efforts to understand the normal functions of TDP-43 and the molecular basis of dysregulation that occurs in TDP-43 proteinopathies. Here, we highlight recent findings examining TDP-43 molecular functions with particular emphasis on stress-mediated regulation of TDP-43 localization, putative downstream TDP-43 target genes and RNAs, as well as TDP-43 interacting proteins, all of which represent viable points of therapeutic intervention for ALS, FTLD-TDP and related proteinopathies. Finally, we review current mouse models of TDP-43 and discuss their similarities and potential relevance to human TDP-43 proteinopathies including ALS and FTLD-TDP.
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42
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Drepper C, Sendtner M. A new postal code for dendritic mRNA transport in neurons. EMBO Rep 2011; 12:614-6. [PMID: 21681203 DOI: 10.1038/embor.2011.119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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43
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Budini M, Buratti E. TDP-43 autoregulation: implications for disease. J Mol Neurosci 2011; 45:473-9. [PMID: 21681666 DOI: 10.1007/s12031-011-9573-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 06/06/2011] [Indexed: 12/13/2022]
Abstract
TDP-43 is a nuclear protein that has been shown to play a central role in RNA metabolism. In recent years, this protein has become very important in the study of neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration (FTLD). These diseases share, as common feature, the presence of abnormally aggregated, posttranslationally modified, and mislocalized TDP-43 in the cell cytoplasm of both neurons and glial cells. A major question in TDP-43 research is represented by the investigation of the mechanism(s) that trigger this process and its potential consequences. Regarding the first issue, it is likely that relative protein expression levels might play an important role as has been demonstrated for many protein aggregation processes. In fact, the eventual misregulation of TDP-43 expression leading to enhanced protein production might well correlate with enhanced aggregation, and thus results in increasingly harmful gain- or loss-of-function effects on cellular metabolism. For this reason, it is important to determine the mechanisms that act to regulate TDP-43 levels within the cell. In normal conditions, it is now clear that TDP-43 can modulate its own protein levels through a negative feedback loop triggered by binding to its own RNA in the 3'UTR region leading to mRNA degradation. This work discusses how an eventual disruption of this mechanism might affect TDP-43 pathology, focusing in particular on its association with stress granules and intrinsic aggregation properties.
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Affiliation(s)
- Mauricio Budini
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34012, Trieste, Italy
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44
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Hasegawa M, Nonaka T, Tsuji H, Tamaoka A, Yamashita M, Kametani F, Yoshida M, Arai T, Akiyama H. Molecular dissection of TDP-43 proteinopathies. J Mol Neurosci 2011; 45:480-5. [PMID: 21678031 DOI: 10.1007/s12031-011-9571-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Accepted: 06/02/2011] [Indexed: 12/12/2022]
Abstract
TDP-43 has been identified as a major component of ubiquitin-positive tau-negative cytoplasmic inclusions in frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U) and in amyotrophic lateral sclerosis (ALS). We raised antibodies to phosphopeptides representing 36 out of 64 candidate phosphorylation sites of human TDP-43 and showed that the antibodies to pS379, pS403/404, pS409, pS410 and pS409/410 labeled the inclusions, but not the nuclei. Immunoblot analyses demonstrated that the antibodies recognized TDP-43 at ~45 kDa, smearing substances and 18-26 kDa C-terminal fragments. Furthermore, the band patterns of the C-terminal fragments differed between neuropathological subtypes, but were indistinguishable between brain regions and spinal cord in each individual patient. Protease treatment of Sarkosyl-insoluble TDP-43 suggests that the different band patterns of the C-terminal fragments reflect different conformations of abnormal TDP-43 molecules between the diseases. These results suggest that molecular species of abnormal TDP-43 are different between the diseases and that they propagate from affected cells to other cells during disease progression and determine the clinicopathological phenotypes of the diseases.
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Affiliation(s)
- Masato Hasegawa
- Department of Neuropathology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan.
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