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Insight into the Folding and Dimerization Mechanisms of the N-Terminal Domain from Human TDP-43. Int J Mol Sci 2020; 21:ijms21176259. [PMID: 32872449 PMCID: PMC7504384 DOI: 10.3390/ijms21176259] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 08/21/2020] [Accepted: 08/25/2020] [Indexed: 02/06/2023] Open
Abstract
TAR DNA-binding protein 43 (TDP-43) is a 414-residue long nuclear protein whose deposition into intraneuronal insoluble inclusions has been associated with the onset of amyotrophic lateral sclerosis (ALS) and other diseases. This protein is physiologically a homodimer, and dimerization occurs through the N-terminal domain (NTD), with a mechanism on which a full consensus has not yet been reached. Furthermore, it has been proposed that this domain is able to affect the formation of higher molecular weight assemblies. Here, we purified this domain and carried out an unprecedented characterization of its folding/dimerization processes in solution. Exploiting a battery of biophysical approaches, ranging from FRET to folding kinetics, we identified a head-to-tail arrangement of the monomers within the dimer. We found that folding of NTD proceeds through the formation of a number of conformational states and two parallel pathways, while a subset of molecules refold slower, due to proline isomerism. The folded state appears to be inherently prone to form high molecular weight assemblies. Taken together, our results indicate that NTD is inherently plastic and prone to populate different conformations and dimeric/multimeric states, a structural feature that may enable this domain to control the assembly state of TDP-43.
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52
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Bienz M. Head-to-Tail Polymerization in the Assembly of Biomolecular Condensates. Cell 2020; 182:799-811. [PMID: 32822572 DOI: 10.1016/j.cell.2020.07.037] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/15/2020] [Accepted: 07/27/2020] [Indexed: 12/14/2022]
Abstract
Clustering of macromolecules is a fundamental cellular device underlying diverse biological processes that require high-avidity binding to effectors and substrates. Often, this involves a transition between diffuse and locally concentrated molecules akin to biophysical phase separation observable in vitro. One simple mechanistic paradigm underlying physiologically relevant phase transitions in cells is the reversible head-to-tail polymerization of hub proteins into filaments that are cross-linked by dimerization into dynamic three-dimensional molecular condensates. While many diverse folds and motifs can mediate dimerization, only two structurally distinct domains have been discovered so far to undergo head-to-tail polymerization, though these are widespread among all living kingdoms.
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Affiliation(s)
- Mariann Bienz
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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53
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Liu J, Zhou M, Ouyang Y, Du L, Xu L, Li H. Identification of potential biomarkers and their clinical significance in gastric cancer using bioinformatics analysis methods. PeerJ 2020; 8:e9174. [PMID: 33062405 PMCID: PMC7527772 DOI: 10.7717/peerj.9174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/21/2020] [Indexed: 01/07/2023] Open
Abstract
Background Alternative splicing (AS) is an important mechanism for regulating gene expression and proteome diversity. Tumor-alternative splicing can reveal a large class of new splicing-associated potential new antigens that may affect the immune response and can be used for immunotherapy. Methods The RNA-seq transcriptome data and clinical information of stomach adenocarcinoma (STAD) cohort were downloaded from The Cancer Genome Atlas (TCGA) database data portal, and data of splicing events were obtained from the SpliceSeq database. Predicting genes were validated by Asian cancer research group (ACRG) cohort and Oncomine database. RT-qPCR was used to analysis the expression of ECT2 in STAD. Results A total of 32,166 AS events were identified, among which 2,042 AS events were significantly associated with patients survival. Biological pathway analysis indicated that these genes play an important role in regulating gastric cancer-related processes such as GTPase activity and PI3K-Akt signaling pathway. Next, we derived a risk signature, using alternate acceptor, that is an independent prognostic marker. Moreover, high ECT2 expression was associated with poorer prognosis in STAD. Multivariate survival analysis demonstrated that high ECT2 expression was an independent risk factor for overall survival. Gene set enrichment analysis revealed that high ECT2 expression was enriched for hallmarks of malignant tumors. The ACRG cohort and Oncomine also showed that high ECT2 expression was associated with poorer prognosis in gastric cancer patients. Finally, RT-qPCR showed ECT2 expression was higher in STAD compared to the normal tissues. Conclusion This study excavated the alternative splicing events in gastric cancer, and found ECT2 might be a biomarkers for diagnosis and prognosis.
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Affiliation(s)
- Jie Liu
- Gastroenterology, Jining No.1 People's Hospital, Jining, China
| | - Miao Zhou
- Gastroenterology, Jining No.1 People's Hospital, Jining, China
| | - Yangyang Ouyang
- Gastroenterology, Jining No.1 People's Hospital, Jining, China
| | - Laifeng Du
- General Medicine, Jining Prison Hospital, Jining, China
| | - Lingbo Xu
- Obstetrical, Jining No.1 People's Hospital, Jining, China
| | - Hongyun Li
- Gastroenterology, Jining No.1 People's Hospital, Jining, China
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54
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Kim T, Song B, Lee IS. Drosophila Glia: Models for Human Neurodevelopmental and Neurodegenerative Disorders. Int J Mol Sci 2020; 21:E4859. [PMID: 32660023 PMCID: PMC7402321 DOI: 10.3390/ijms21144859] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 06/27/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022] Open
Abstract
Glial cells are key players in the proper formation and maintenance of the nervous system, thus contributing to neuronal health and disease in humans. However, little is known about the molecular pathways that govern glia-neuron communications in the diseased brain. Drosophila provides a useful in vivo model to explore the conserved molecular details of glial cell biology and their contributions to brain function and disease susceptibility. Herein, we review recent studies that explore glial functions in normal neuronal development, along with Drosophila models that seek to identify the pathological implications of glial defects in the context of various central nervous system disorders.
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Affiliation(s)
| | | | - Im-Soon Lee
- Department of Biological Sciences, Center for CHANS, Konkuk University, Seoul 05029, Korea; (T.K.); (B.S.)
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55
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Romano G, Klima R, Feiguin F. TDP-43 prevents retrotransposon activation in the Drosophila motor system through regulation of Dicer-2 activity. BMC Biol 2020; 18:82. [PMID: 32620127 PMCID: PMC7334854 DOI: 10.1186/s12915-020-00816-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/19/2020] [Indexed: 02/06/2023] Open
Abstract
Background Mutations in the small RNA-binding protein TDP-43 lead to the formation of insoluble cytoplasmic aggregates that have been associated with the onset and progression of amyotrophic lateral sclerosis (ALS), a neurodegenerative disorder affecting homeostasis of the motor system which is also characterized by aberrant expression of retrotransposable elements (RTEs). Although the TDP-43 function was shown to be required in the neurons and glia to maintain the organization of neuromuscular synapses and prevent denervation of the skeletal muscles, the molecular mechanisms involved in physiological dysregulation remain elusive. Here, we address this issue using a null mutation of the TDP-43 Drosophila homolog, TBPH. Results Using genome-wide gene expression profiles, we detected a strong upregulation of RTE expression in TBPH-null Drosophila heads, while the genetic rescue of the TDP-43 function reverted these modifications. Furthermore, we found that TBPH modulates the small interfering RNA (siRNA) silencing machinery responsible for RTE repression. Molecularly, we observed that TBPH regulates the expression levels of Dicer-2 by direct protein-mRNA interactions in vivo. Accordingly, the genetic or pharmacological recovery of Dicer-2 activity was sufficient to repress retrotransposon activation and promote motoneuron axonal wrapping and synaptic growth in TBPH-null Drosophila. Conclusions We identified an upregulation of RTE expression in TBPH-null Drosophila heads and demonstrate that defects in the siRNA pathway lead to RTE upregulation and motoneuron degeneration. Our results describe a novel physiological role of endogenous TDP-43 in the prevention of RTE-induced neurological alterations through the modulation of Dicer-2 activity and the siRNA pathway.
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Affiliation(s)
- Giulia Romano
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149, Trieste, Italy
| | - Raffaella Klima
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149, Trieste, Italy
| | - Fabian Feiguin
- International Centre for Genetic Engineering and Biotechnology, Padriciano 99, 34149, Trieste, Italy.
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56
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Jamerlan A, An SSA. The influence of Aβ-dependent and independent pathways on TDP-43 proteinopathy in Alzheimer's disease: a possible connection to LATE-NC. Neurobiol Aging 2020; 95:161-167. [PMID: 32814257 DOI: 10.1016/j.neurobiolaging.2020.06.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 06/22/2020] [Accepted: 06/25/2020] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder that results from the accumulation of plaques by cleaved Aβ42 peptides as well as neurofibrillary tangles of tau proteins. This accumulation triggers a complex cascade of cytotoxic, neuroinflammatory, and oxidative stresses that lead to neuronal death throughout the progression of the disease. Much of research in AD focused on the 2 pathologic proteins. Interestingly, another form of dementia with similar clinical manifestations of AD, but preferentially affected much older individuals, was termed as limbic-predominant age-related transactive response DNA-binding protein 43 (TDP-43) encephalopathy (LATE) and involved the cytotoxic intraneuronal deposition of phosphorylated TDP-43. TDP-43 proteinopathy was also found to be involved in AD pathology leading to the possibility that AD and LATE may share a common upstream etiology. This paper discusses the roles molecular pathways known in AD may have on influencing TDP-43 proteinopathy and the development of AD, LATE, or the 2 being comorbid with each other.
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Affiliation(s)
- Angelo Jamerlan
- Department of Bionano Technology, Gachon University, Seongnam-si, Republic of Korea
| | - Seong Soo A An
- Department of Bionano Technology, Gachon University, Seongnam-si, Republic of Korea.
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57
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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: 59] [Impact Index Per Article: 14.8] [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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58
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Van Pelt KM, Truttmann MC. Caenorhabditis elegans as a model system for studying aging-associated neurodegenerative diseases. TRANSLATIONAL MEDICINE OF AGING 2020; 4:60-72. [PMID: 34327290 PMCID: PMC8317484 DOI: 10.1016/j.tma.2020.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Neurodegenerative diseases (NDs) are a heterogeneous group of aging-associated disorders characterized by the disruption of cellular proteostasis machinery and the misfolding of distinct protein species to form toxic aggregates in neurons. The increasing prevalence of NDs represents a growing healthcare burden worldwide, a concern compounded by the fact that few, if any, treatments exist to target the underlying cause of these diseases. Consequently, the application of a high-throughput, physiologically relevant model system to studies dissecting the molecular mechanisms governing ND pathology is crucial for identifying novel avenues for the development of targeted therapeutics. The nematode Caenorhabditis elegans (C. elegans) has emerged as a powerful tool for the study of disease mechanisms due to its ease of genetic manipulation and swift cultivation, while providing a whole-animal system amendable to numerous molecular and biochemical techniques. To date, numerous C. elegans models have been generated for a variety of NDs, allowing for the large-scale in vivo study of protein-conformation disorders. Furthermore, the comparatively low barriers to entry in the development of transgenic worm models have facilitated the modeling of rare or "orphan" NDs, thereby providing unparalleled insight into the shared mechanisms underlying these pathologies. In this review, we summarize findings from a comprehensive collection of C. elegans neurodegenerative disease models of varying prevalence to emphasize shared mechanisms of proteotoxicity, and highlight the utility of these models in elucidating the molecular basis of ND pathologies.
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Affiliation(s)
- Kate M. Van Pelt
- Cellular & Molecular Biology Program, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Matthias C. Truttmann
- Cellular & Molecular Biology Program, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, 48109, USA
- Geriatrics Center, University of Michigan, Ann Arbor, MI, 48109, USA
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59
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Springhower CE, Rosen MK, Chook YM. Karyopherins and condensates. Curr Opin Cell Biol 2020; 64:112-123. [PMID: 32474299 DOI: 10.1016/j.ceb.2020.04.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/26/2020] [Accepted: 04/04/2020] [Indexed: 01/25/2023]
Abstract
Several aggregation-prone RNA-binding proteins, including FUS, EWS, TAF15, hnRNP A1, hnRNP A2, and TDP-43, are mutated in neurodegenerative diseases. The nuclear-cytoplasmic distribution of these proteins is controlled by proteins in the karyopherin family of nuclear transport factors (Kaps). Recent studies have shown that Kaps not only transport these proteins but also inhibit their self-association/aggregation, acting as molecular chaperones. This chaperone activity is impaired for disease-causing mutants of the RNA-binding proteins. Here, we review physical data on the mechanisms of self-association of several disease-associated RNA-binding proteins, through liquid-liquid phase separation and amyloid fiber formation. In each case, we relate these data to biophysical, biochemical, and cell biological data on the inhibition of self-association by Kaps. Our analyses suggest that Kaps may be effective chaperones because they contain large surfaces with diverse physical properties that enable them to engage multiple different regions of their cargo proteins, blocking self-association.
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Affiliation(s)
- Charis E Springhower
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Michael K Rosen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Yuh Min Chook
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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60
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Elliott E, Bailey O, Waldron FM, Hardingham GE, Chandran S, Gregory JM. Therapeutic Targeting of Proteostasis in Amyotrophic Lateral Sclerosis-a Systematic Review and Meta-Analysis of Preclinical Research. Front Neurosci 2020; 14:511. [PMID: 32523508 PMCID: PMC7261930 DOI: 10.3389/fnins.2020.00511] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/24/2020] [Indexed: 12/12/2022] Open
Abstract
Background: Amyotrophic lateral sclerosis (ALS) is a rapidly progressive fatal neurodegenerative condition. There are no effective treatments. The only globally licensed medication, that prolongs life by 2–3 months, was approved by the FDA in 1995. One reason for the absence of effective treatments is disease heterogeneity noting that ALS is clinically heterogeneous and can be considered to exist on a neuropathological spectrum with frontotemporal dementia. Despite this significant clinical heterogeneity, protein misfolding has been identified as a unifying pathological feature in these cases. Based on this shared pathophysiology, we carried out a systematic review and meta-analysis to assess the therapeutic efficacy of compounds that specifically target protein misfolding in preclinical studies of both ALS and FTD. Methods: Three databases: (i) PubMed, (ii) MEDLINE, and (iii) EMBASE were searched. All studies comparing the effect of treatments targeting protein misfolding in pre-clinical ALS or FTD models to a control group were retrieved. Results: Systematic review identified 70 pre-clinical studies investigating the effects of therapies targeting protein misfolding on survival. Meta-analysis revealed that targeting protein misfolding did significantly improve survival compared to untreated controls (p < 0.001, df = 68, α = 0.05, CI 1.05–1.16), with no evidence of heterogeneity between studies (I2 = 0%). Further subgroup analyses, evaluating the effect of timing of these interventions, showed that, only treating prior to symptom onset (n = 33), significantly improved survival (p < 0.001, df = 31, α = 0.05, CI 1.08–1.29), although this likely reflects the inadequate sample size of later time points. Furthermore, arimoclomol was found to significantly reduce secondary outcome measures including: (i) histological outcomes, (ii) behavioral outcomes, and (iii) biochemical outcomes (p < 0.005). Conclusions: This analysis supports the hypothesis that protein misfolding plays an important role in the pathogenesis of ALS and FTD and that targeting protein misfolding, at least in pre-clinical models, can significantly improve survival, especially if such an intervention is administered prior to symptom onset.
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Affiliation(s)
- Elizabeth Elliott
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom.,The Anne Rowling Regenerative Neurology Clinic, The University of Edinburgh, Edinburgh, United Kingdom.,The Euan MacDonald Centre, University of Edinburgh, Edinburgh, United Kingdom.,Edinburgh Neuroscience, The University of Edinburgh, Edinburgh, United Kingdom.,MRC Edinburgh Brain Bank, Academic Department of Neuropathology, The University of Edinburgh, Edinburgh, United Kingdom
| | - Olivia Bailey
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom.,The Anne Rowling Regenerative Neurology Clinic, The University of Edinburgh, Edinburgh, United Kingdom.,The Euan MacDonald Centre, University of Edinburgh, Edinburgh, United Kingdom
| | - Fergal M Waldron
- Ashworth Laboratories, Institute of Evolutionary Biology and Centre for Immunity Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Giles E Hardingham
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom.,The Euan MacDonald Centre, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Siddharthan Chandran
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom.,The Anne Rowling Regenerative Neurology Clinic, The University of Edinburgh, Edinburgh, United Kingdom.,The Euan MacDonald Centre, University of Edinburgh, Edinburgh, United Kingdom.,Edinburgh Neuroscience, The University of Edinburgh, Edinburgh, United Kingdom.,Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom.,Centre for Brain Development and Repair, inStem, Bangalore, India.,MRC Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh, United Kingdom
| | - Jenna M Gregory
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom.,Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom.,The Anne Rowling Regenerative Neurology Clinic, The University of Edinburgh, Edinburgh, United Kingdom.,The Euan MacDonald Centre, University of Edinburgh, Edinburgh, United Kingdom.,Edinburgh Neuroscience, The University of Edinburgh, Edinburgh, United Kingdom.,MRC Edinburgh Brain Bank, Academic Department of Neuropathology, The University of Edinburgh, Edinburgh, United Kingdom.,Edinburgh Pathology, The University of Edinburgh, Edinburgh, United Kingdom
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61
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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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62
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Donde A, Sun M, Jeong YH, Wen X, Ling J, Lin S, Braunstein K, Nie S, Wang S, Chen L, Wong PC. Upregulation of ATG7 attenuates motor neuron dysfunction associated with depletion of TARDBP/TDP-43. Autophagy 2020; 16:672-682. [PMID: 31242080 PMCID: PMC7138241 DOI: 10.1080/15548627.2019.1635379] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 05/29/2019] [Accepted: 06/20/2019] [Indexed: 12/12/2022] Open
Abstract
A shared neuropathological hallmark in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is nuclear clearance and cytoplasmic aggregation of TARDBP/TDP-43 (TAR DNA binding protein). We previously showed that the ability of TARDBP to repress nonconserved cryptic exons was impaired in brains of patients with ALS and FTD, suggesting that its nuclear depletion contributes to neurodegeneration. However, the critical pathways impacted by the failure to repress cryptic exons that may contribute to neurodegeneration remain undefined. Here, we report that transcriptome analysis of TARDBP-deficient neurons revealed downregulation of ATG7, a critical gene required for macroautophagy/autophagy. Mouse and Drosophila models lacking TARDBP/TBPH in motor neurons exhibiting age-dependent neurodegeneration and motor deficits showed reduction of ATG7 and accumulation of SQSTM1/p62 inclusions. Importantly, genetic upregulation of the autophagy pathway improved motor function and survival in TBPH-deficient flies. Together with our observation that ATG7 is reduced in ALS-FTD brain tissues, these findings identify the autophagy pathway as one key effector of nuclear depletion of TARDBP that contributes to neurodegeneration. We thus suggest that the autophagy pathway is a therapeutic target for ALS-FTD and other disorders exhibiting TARDBP pathology.Abbreviations: ALS: amyotrophic lateral sclerosis; ANOVA: analysis of variance; ChAT: choline acetyltransferase; CTSD: cathepsin D; FTD: frontotemporal dementia; LAMP1: lysosomal associated membrane protein 1; NMJ: neuromuscular junction; RBFOX3/NeuN: RNA binding fox-1 homolog 3; SQSTM1: sequestosome 1; TARDBP/TDP-43: TAR DNA binding protein 43.
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Affiliation(s)
- Aneesh Donde
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mingkuan Sun
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yun Ha Jeong
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, Korea
| | - Xinrui Wen
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jonathan Ling
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sophie Lin
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kerstin Braunstein
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shuke Nie
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sheng Wang
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Liam Chen
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Philip C. Wong
- Departments of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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63
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Weskamp K, Tank EM, Miguez R, McBride JP, Gómez NB, White M, Lin Z, Gonzalez CM, Serio A, Sreedharan J, Barmada SJ. Shortened TDP43 isoforms upregulated by neuronal hyperactivity drive TDP43 pathology in ALS. J Clin Invest 2020; 130:1139-1155. [PMID: 31714900 PMCID: PMC7269575 DOI: 10.1172/jci130988] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 11/06/2019] [Indexed: 12/13/2022] Open
Abstract
Cortical hyperexcitability and mislocalization of the RNA-binding protein TDP43 are highly conserved features in amyotrophic lateral sclerosis (ALS). Nevertheless, the relationship between these phenomena remains poorly defined. Here, we showed that hyperexcitability recapitulates TDP43 pathology by upregulating shortened TDP43 (sTDP43) splice isoforms. These truncated isoforms accumulated in the cytoplasm and formed insoluble inclusions that sequestered full-length TDP43 via preserved N-terminal interactions. Consistent with these findings, sTDP43 overexpression was toxic to mammalian neurons, suggesting neurodegeneration arising from complementary gain- and loss-of-function mechanisms. In humans and mice, sTDP43 transcripts were enriched in vulnerable motor neurons, and we observed a striking accumulation of sTDP43 within neurons and glia of ALS patients. Collectively, these studies uncover a pathogenic role for alternative TDP43 isoforms in ALS, and implicate sTDP43 as a key contributor to the susceptibility of motor neurons in this disorder.
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Affiliation(s)
| | | | | | - Jonathon P. McBride
- Department of Neurology
- Cellular and Molecular Biology Program, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Nicolás B. Gómez
- Department of Neurology
- Cellular and Molecular Biology Program, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Ziqiang Lin
- Department of Basic and Clinical Neuroscience and
| | - Carmen Moreno Gonzalez
- Centre for Craniofacial and Regenerative Biology, King’s College London, London, United Kingdom
| | - Andrea Serio
- Centre for Craniofacial and Regenerative Biology, King’s College London, London, United Kingdom
| | | | - Sami J. Barmada
- Department of Neurology
- Neuroscience Graduate Program, and
- Cellular and Molecular Biology Program, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
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64
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Loganathan S, Lehmkuhl EM, Eck RJ, Zarnescu DC. To Be or Not To Be…Toxic-Is RNA Association With TDP-43 Complexes Deleterious or Protective in Neurodegeneration? Front Mol Biosci 2020; 6:154. [PMID: 31998750 PMCID: PMC6965497 DOI: 10.3389/fmolb.2019.00154] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/12/2019] [Indexed: 12/13/2022] Open
Abstract
TAR DNA binding protein (TDP-43) is a nucleic acid binding protein associated with insoluble cytoplasmic aggregates in several neurodegenerative disorders, including 97% of the ALS cases. In healthy individuals, TDP-43 is primarily localized to the nucleus; it can shuttle between the nucleus and the cytoplasm, and is involved in several aspects of RNA processing including transcription, splicing, RNA stability, transport, localization, stress granule (SG) formation, and translation. Upon stress, TDP-43 aggregates in the cytoplasm and associates with several types of RNA and protein assemblies, resulting in nuclear depletion of TDP-43. Under conditions of prolonged stress, cytoplasmic TDP-43 undergoes liquid-liquid phase separation (LLPS) and becomes less mobile. Evidence exists to support a scenario in which insoluble TDP-43 complexes sequester RNA and/or proteins causing disturbances in both ribostasis and proteostasis, which in turn contribute to neurodegeneration. However, the relationship between RNA binding and TDP-43 toxicity remains unclear. Recent studies provide conflicting views on the role of RNA in TDP-43 toxicity, with some finding RNA as a toxic factor whereby RNA binding contributes to TDP-43 toxicity, while others find RNA to be a protective factor that inhibits TDP-43 aggregation. Here we review and discuss these recent reports, which ultimately highlight the importance of understanding the heterogeneity of TDP-43 assemblies and collectively point to solubilizing TDP-43 as a potential therapeutic strategy.
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Affiliation(s)
| | - Erik M Lehmkuhl
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States
| | - Randall J Eck
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States.,Department of Neuroscience, University of Arizona, Tucson, AZ, United States
| | - Daniela C Zarnescu
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States.,Department of Neuroscience, University of Arizona, Tucson, AZ, United States
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65
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Pillai M, Jha SK. Early Metastable Assembly during the Stress-Induced Formation of Worm-like Amyloid Fibrils of Nucleic Acid Binding Domains of TDP-43. Biochemistry 2020; 59:315-328. [PMID: 31898895 DOI: 10.1021/acs.biochem.9b00780] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
TDP-43 protein travels between the cytosol and the nucleus to perform its nucleic acid binding functions through its two tandem RNA recognition motif domains (TDP-43tRRM). When exposed to various environmental stresses, it forms abnormal aggregates in the cytosol of neurons, which are the hallmarks of amyotrophic lateral sclerosis and other TDP-43 proteinopathies. However, the nature of early structural changes upon stress sensing and the consequent steps during the course of aggregation are not well understood. In this study, we show that under low-pH conditions, mimicking starvation stress, TDP-43tRRM undergoes a conformational opening reaction linked to the protonation of buried ionizable residues and grows into a metastable oligomeric assembly (called the "low-pH form" or the "L form"). In the L form, the protein molecules have disrupted tertiary structure, solvent-exposed hydrophobic patches, and mobile side chains but the native-like secondary structure remains intact. The L form structure is held by weak interactions and has a steep dependence on ionic strength. In the presence of as little as 15 mM KCl, it fully misfolds and further oligomerizes to form a β-sheet rich "β form" in at least two distinct steps. The β form has an ordered, stable structure that resembles worm-like amyloid fibrils. The unstructured regions of the protein gain structure during L ⇌ β conversion. Our results suggest that TDP-43tRRM could function as a stress sensor and support a recent model in which stress sensing during neurodegeneration occurs by assembly of proteins into metastable assemblies that are precursors to the solid aggregates.
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Affiliation(s)
- Meenakshi Pillai
- Physical and Materials Chemistry Division , CSIR-National Chemical Laboratory , Dr. Homi Bhabha Road , Pune 411008 , India.,Academy of Scientific and Innovative Research (AcSIR) , Ghaziabad 201002 , India
| | - Santosh Kumar Jha
- Physical and Materials Chemistry Division , CSIR-National Chemical Laboratory , Dr. Homi Bhabha Road , Pune 411008 , India.,Academy of Scientific and Innovative Research (AcSIR) , Ghaziabad 201002 , India
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66
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Bhopatkar AA, Uversky VN, Rangachari V. Granulins modulate liquid-liquid phase separation and aggregation of the prion-like C-terminal domain of the neurodegeneration-associated protein TDP-43. J Biol Chem 2020; 295:2506-2519. [PMID: 31911437 DOI: 10.1074/jbc.ra119.011501] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/02/2020] [Indexed: 12/13/2022] Open
Abstract
TAR DNA-binding protein 43 (TDP-43) has emerged as a key player in many neurodegenerative pathologies, including frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Hallmarks of both FTLD and ALS are the toxic cytoplasmic inclusions of the prion-like C-terminal fragments of TDP-43 CTD (TDP-43 C-terminal domain), formed upon proteolytic cleavage of full-length TDP-43 in the nucleus and subsequent transport to the cytoplasm. Both full-length TDP-43 and its CTD are also known to form stress granules by coacervating with RNA in the cytoplasm during stress and may be involved in these pathologies. Furthermore, mutations in the PGRN gene, leading to haploinsufficiency and diminished function of progranulin (PGRN) protein, are strongly linked to FTLD and ALS. Recent reports have indicated that proteolytic processing of PGRN to smaller protein modules called granulins (GRNs) contributes to FTLD and ALS progression, with specific GRNs exacerbating TDP-43-induced cytotoxicity. Here we investigated the interactions between the proteolytic products of both TDP-43 and PGRN. Based on structural disorder and charge distributions, we hypothesized that GRN-3 and GRN-5 could interact with the TDP-43 CTD. We show that, under both reducing and oxidizing conditions, GRN-3 and GRN-5 interact with and differentially modulate TDP-43 CTD aggregation and/or liquid-liquid phase separation in vitro GRN-3 promoted insoluble aggregates of the TDP-43 CTD while GRN-5 mediated liquid-liquid phase separation. These results constitute the first observation of an interaction between GRNs and TDP-43, suggesting a mechanism by which attenuated PGRN function could lead to familial FTLD or ALS.
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Affiliation(s)
- Anukool A Bhopatkar
- Department of Chemistry and Biochemistry, School of Mathematics and Natural Sciences, University of Southern Mississippi, Hattiesburg, Mississippi 39406
| | - Vladimir N Uversky
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, Florida 33620; Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
| | - Vijayaraghavan Rangachari
- Department of Chemistry and Biochemistry, School of Mathematics and Natural Sciences, University of Southern Mississippi, Hattiesburg, Mississippi 39406.
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67
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Lee YCG, Ventura IM, Rice GR, Chen DY, Colmenares SU, Long M. Rapid Evolution of Gained Essential Developmental Functions of a Young Gene via Interactions with Other Essential Genes. Mol Biol Evol 2020; 36:2212-2226. [PMID: 31187122 DOI: 10.1093/molbev/msz137] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
New genes are of recent origin and only present in a subset of species in a phylogeny. Accumulated evidence suggests that new genes, like old genes that are conserved across species, can also take on important functions and be essential for the survival and reproductive success of organisms. Although there are detailed analyses of the mechanisms underlying new genes' gaining fertility functions, how new genes rapidly become essential for viability remains unclear. We focused on a young retro-duplicated gene (CG7804, which we named Cocoon) in Drosophila that originated between 4 and 10 Ma. We found that, unlike its evolutionarily conserved parental gene, Cocoon has evolved under positive selection and accumulated many amino acid differences at functional sites from the parental gene. Despite its young age, Cocoon is essential for the survival of Drosophila melanogaster at multiple developmental stages, including the critical embryonic stage, and its expression is essential in different tissues from those of its parental gene. Functional genomic analyses found that Cocoon acquired unique DNA-binding sites and has a contrasting effect on gene expression to that of its parental gene. Importantly, Cocoon binding predominantly locates at genes that have other essential functions and/or have multiple gene-gene interactions, suggesting that Cocoon acquired novel essential function to survival through forming interactions that have large impacts on the gene interaction network. Our study is an important step toward deciphering the evolutionary trajectory by which new genes functionally diverge from parental genes and become essential.
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Affiliation(s)
- Yuh Chwen G Lee
- Department of Ecology and Evolution, The University of Chicago, Chicago, IL.,Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Iuri M Ventura
- Department of Ecology and Evolution, The University of Chicago, Chicago, IL.,CAPES Foundation, Ministry of Education of Brazil, Brasília, DF, Brazil
| | - Gavin R Rice
- Department of Evolution and Ecology, University of California, Davis, Davis, CA.,Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
| | - Dong-Yuan Chen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Serafin U Colmenares
- Division of Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Manyuan Long
- Department of Ecology and Evolution, The University of Chicago, Chicago, IL
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68
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Shenoy J, El Mammeri N, Dutour A, Berbon M, Saad A, Lends A, Morvan E, Grélard A, Lecomte S, Kauffmann B, Theillet FX, Habenstein B, Loquet A. Structural dissection of amyloid aggregates of TDP-43 and its C-terminal fragments TDP-35 and TDP-16. FEBS J 2019; 287:2449-2467. [PMID: 31782904 DOI: 10.1111/febs.15159] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 10/17/2019] [Accepted: 11/27/2019] [Indexed: 12/12/2022]
Abstract
The TAR DNA-binding protein (TDP-43) self-assembles into prion-like aggregates considered to be the structural hallmark of amyotrophic lateral sclerosis and frontotemporal dementia. Here, we use a combination of electron microscopy, X-ray fiber diffraction, Fourier-transform infrared spectroscopy analysis, and solid-state NMR spectroscopy to investigate the molecular organization of different TDP constructs, namely the full-length TDP-43 (1-414), two C-terminal fragments [TDP-35 (90-414) and TDP-16 (267-414)], and a C-terminal truncated fragment (TDP-43 ∆GaroS2), in their fibrillar state. Although the different protein constructs exhibit similar fibril morphology and a typical cross-β signature by X-ray diffraction, solid-state NMR indicates that TDP-43 and TDP-35 share the same polymorphic molecular structure, while TDP-16 encompasses a well-ordered amyloid core. We identified several residues in the so-called C-terminal GaroS2 (368-414) domain that participates in the rigid core of TDP-16 fibrils, underlining its importance during the aggregation process. Our findings demonstrate that C-terminal fragments can adopt a different molecular conformation in isolation or in the context of the full-length assembly, suggesting that the N-terminal domain and RRM domains play an important role in the TDP-43 amyloid transition.
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Affiliation(s)
- Jayakrishna Shenoy
- CBMN (UMR5248), Université de Bordeaux - CNRS - IPB, Institut Européen de Chimie et Biologie, Pessac, France
| | - Nadia El Mammeri
- CBMN (UMR5248), Université de Bordeaux - CNRS - IPB, Institut Européen de Chimie et Biologie, Pessac, France
| | - Antoine Dutour
- CBMN (UMR5248), Université de Bordeaux - CNRS - IPB, Institut Européen de Chimie et Biologie, Pessac, France
| | - Mélanie Berbon
- CBMN (UMR5248), Université de Bordeaux - CNRS - IPB, Institut Européen de Chimie et Biologie, Pessac, France
| | - Ahmad Saad
- CBMN (UMR5248), Université de Bordeaux - CNRS - IPB, Institut Européen de Chimie et Biologie, Pessac, France
| | - Alons Lends
- CBMN (UMR5248), Université de Bordeaux - CNRS - IPB, Institut Européen de Chimie et Biologie, Pessac, France
| | - Estelle Morvan
- Université de Bordeaux, CNRS, INSERM, UMS3033, Institut Européen de Chimie et Biologie (IECB), Pessac, France
| | - Axelle Grélard
- CBMN (UMR5248), Université de Bordeaux - CNRS - IPB, Institut Européen de Chimie et Biologie, Pessac, France
| | - Sophie Lecomte
- CBMN (UMR5248), Université de Bordeaux - CNRS - IPB, Institut Européen de Chimie et Biologie, Pessac, France
| | - Brice Kauffmann
- Université de Bordeaux, CNRS, INSERM, UMS3033, Institut Européen de Chimie et Biologie (IECB), Pessac, France
| | - François-Xavier Theillet
- Institut de Biologie Intégrative de la Cellule, CEA, CNRS, Université Paris Sud, UMR 9198, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Birgit Habenstein
- CBMN (UMR5248), Université de Bordeaux - CNRS - IPB, Institut Européen de Chimie et Biologie, Pessac, France
| | - Antoine Loquet
- CBMN (UMR5248), Université de Bordeaux - CNRS - IPB, Institut Européen de Chimie et Biologie, Pessac, France
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69
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François-Moutal L, Perez-Miller S, Scott DD, Miranda VG, Mollasalehi N, Khanna M. Structural Insights Into TDP-43 and Effects of Post-translational Modifications. Front Mol Neurosci 2019; 12:301. [PMID: 31920533 PMCID: PMC6934062 DOI: 10.3389/fnmol.2019.00301] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/25/2019] [Indexed: 12/12/2022] Open
Abstract
Transactive response DNA binding protein (TDP-43) is a key player in neurodegenerative diseases. In this review, we have gathered and presented structural information on the different regions of TDP-43 with high resolution structures available. A thorough understanding of TDP-43 structure, effect of modifications, aggregation and sites of localization is necessary as we develop therapeutic strategies targeting TDP-43 for neurodegenerative diseases. We discuss how different domains as well as post-translational modification may influence TDP-43 overall structure, aggregation and droplet formation. The primary aim of the review is to utilize structural insights as we develop an understanding of the deleterious behavior of TDP-43 and highlight locations of established and proposed post-translation modifications. TDP-43 structure and effect on localization is paralleled by many RNA-binding proteins and this review serves as an example of how structure may be modulated by numerous compounding elements.
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Affiliation(s)
- Liberty François-Moutal
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
| | - Samantha Perez-Miller
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
| | - David D Scott
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
| | - Victor G Miranda
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
| | - Niloufar Mollasalehi
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States.,Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States
| | - May Khanna
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ, United States.,Center for Innovation in Brain Science, Tucson, AZ, United States
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70
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Chen HJ, Topp SD, Hui HS, Zacco E, Katarya M, McLoughlin C, King A, Smith BN, Troakes C, Pastore A, Shaw CE. RRM adjacent TARDBP mutations disrupt RNA binding and enhance TDP-43 proteinopathy. Brain 2019; 142:3753-3770. [PMID: 31605140 PMCID: PMC6885686 DOI: 10.1093/brain/awz313] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 07/24/2019] [Accepted: 08/16/2019] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) presents with focal muscle weakness due to motor neuron degeneration that becomes generalized, leading to death from respiratory failure within 3-5 years from symptom onset. Despite the heterogeneity of aetiology, TDP-43 proteinopathy is a common pathological feature that is observed in >95% of ALS and tau-negative frontotemporal dementia (FTD) cases. TDP-43 is a DNA/RNA-binding protein that in ALS and FTD translocates from being predominantly nuclear to form detergent-resistant, hyperphosphorylated aggregates in the cytoplasm of affected neurons and glia. Mutations in TARDBP account for 1-4% of all ALS cases and almost all arise in the low complexity C-terminal domain that does not affect RNA binding and processing. Here we report an ALS/FTD kindred with a novel K181E TDP-43 mutation that is located in close proximity to the RRM1 domain. To offer predictive gene testing to at-risk family members, we undertook a series of functional studies to characterize the properties of the mutation. Spectroscopy studies of the K181E protein revealed no evidence of significant misfolding. Although it is unable to bind to or splice RNA, it forms abundant aggregates in transfected cells. We extended our study to include other ALS-linked mutations adjacent to the RRM domains that also disrupt RNA binding and greatly enhance TDP-43 aggregation, forming detergent-resistant and hyperphosphorylated inclusions. Lastly, we demonstrate that K181E binds to, and sequesters, wild-type TDP-43 within nuclear and cytoplasmic inclusions. Thus, we demonstrate that TDP-43 mutations that disrupt RNA binding greatly enhance aggregation and are likely to be pathogenic as they promote wild-type TDP-43 to mislocalize and aggregate acting in a dominant-negative manner. This study highlights the importance of RNA binding to maintain TDP-43 solubility and the role of TDP-43 aggregation in disease pathogenesis.
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Affiliation(s)
- Han-Jou Chen
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 125 Coldharbour Lane, Camberwell, SE5 9NU, London, UK
- York Biomedical Research Institute, Department of Biology, University of York, Wentworth Way, YO10 5DD, York, UK
| | - Simon D Topp
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 125 Coldharbour Lane, Camberwell, SE5 9NU, London, UK
| | - Ho Sang Hui
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 125 Coldharbour Lane, Camberwell, SE5 9NU, London, UK
| | - Elsa Zacco
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 125 Coldharbour Lane, Camberwell, SE5 9NU, London, UK
| | - Malvika Katarya
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 125 Coldharbour Lane, Camberwell, SE5 9NU, London, UK
| | - Conor McLoughlin
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 125 Coldharbour Lane, Camberwell, SE5 9NU, London, UK
| | - Andrew King
- MRC London Neurodegenerative Diseases Brain Bank, De Crespigny Park, SE5 8AF, London, UK
| | - Bradley N Smith
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 125 Coldharbour Lane, Camberwell, SE5 9NU, London, UK
| | - Claire Troakes
- MRC London Neurodegenerative Diseases Brain Bank, De Crespigny Park, SE5 8AF, London, UK
| | - Annalisa Pastore
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 125 Coldharbour Lane, Camberwell, SE5 9NU, London, UK
| | - Christopher E Shaw
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 125 Coldharbour Lane, Camberwell, SE5 9NU, London, UK
- Centre for Brain Research, University of Auckland, Auckland, New Zealand
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71
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Schmidt HB, Barreau A, Rohatgi R. Phase separation-deficient TDP43 remains functional in splicing. Nat Commun 2019; 10:4890. [PMID: 31653829 PMCID: PMC6814767 DOI: 10.1038/s41467-019-12740-2] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 09/27/2019] [Indexed: 12/12/2022] Open
Abstract
Intrinsically disordered regions (IDRs) are often fast-evolving protein domains of low sequence complexity that can drive phase transitions and are commonly found in many proteins associated with neurodegenerative diseases, including the RNA processing factor TDP43. Yet, how phase separation contributes to the physiological functions of TDP43 in cells remains enigmatic. Here, we combine systematic mutagenesis guided by evolutionary sequence analysis with a live-cell reporter assay of TDP43 phase dynamics to identify regularly-spaced hydrophobic motifs separated by flexible, hydrophilic segments in the IDR as a key determinant of TDP43 phase properties. This heuristic framework allows customization of the material properties of TDP43 condensates to determine effects on splicing function. Remarkably, even a mutant that fails to phase-separate at physiological concentrations can still efficiently mediate the splicing of a quantitative, single-cell splicing reporter and endogenous targets. This suggests that the ability of TDP43 to phase-separate is not essential for its splicing function.
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Affiliation(s)
| | - Ariana Barreau
- Department of Biochemistry, Stanford School of Medicine, Stanford, CA, 94305, USA
| | - Rajat Rohatgi
- Department of Biochemistry, Stanford School of Medicine, Stanford, CA, 94305, USA.
- Department of Medicine, Stanford School of Medicine, Stanford, CA, 94305, USA.
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72
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Vega MV, Nigro A, Luti S, Capitini C, Fani G, Gonnelli L, Boscaro F, Chiti F. Isolation and characterization of soluble human full‐length TDP‐43 associated with neurodegeneration. FASEB J 2019; 33:10780-10793. [DOI: 10.1096/fj.201900474r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Mirella Vivoli Vega
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Alessia Nigro
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Simone Luti
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Claudia Capitini
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Giulia Fani
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Leonardo Gonnelli
- Centro di Ricerca di Risonanze Magnetiche (CERM)University of FlorenceFlorenceItaly
| | | | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
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73
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Makokha GN, Abe-Chayama H, Chowdhury S, Hayes CN, Tsuge M, Yoshima T, Ishida Y, Zhang Y, Uchida T, Tateno C, Akiyama R, Chayama K. Regulation of the Hepatitis B virus replication and gene expression by the multi-functional protein TARDBP. Sci Rep 2019; 9:8462. [PMID: 31186504 PMCID: PMC6560085 DOI: 10.1038/s41598-019-44934-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 12/12/2018] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) infects the liver and is a key risk factor for hepatocellular carcinoma. Identification of host factors that support viral replication is important to understand mechanisms of viral replication and to develop new therapeutic strategies. We identified TARDBP as a host factor that regulates HBV. Silencing or knocking out the protein in HBV infected cells severely impaired the production of viral replicative intermediates, mRNAs, proteins, and virions, whereas ectopic expression of TARDBP rescued production of these products. Mechanistically, we found that the protein binds to the HBV core promoter, as shown by chromatin precipitation as well as mutagenesis and protein-DNA interaction assays. Using LC-MS/MS analysis, we also found that TARDBP binds to a number of other proteins known to support the HBV life cycle, including NPM1, PARP1, Hsp90, HNRNPC, SFPQ, PTBP1, HNRNPK, and PUF60. Interestingly, given its key role as a regulator of RNA splicing, we found that TARDBP has an inhibitory role on pregenomic RNA splicing, which might help the virus to export its non-canonical RNAs from the nucleus without being subjected to unwanted splicing, even though mRNA nuclear export is normally closely tied to RNA splicing. Taken together, our results demonstrate that TARDBP is involved in multiple steps of HBV replication via binding to both HBV DNA and RNA. The protein's broad interactome suggests that TARDBP may function as part of a RNA-binding scaffold involved in HBV replication and that the interaction between these proteins might be a target for development of anti-HBV drugs.
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Affiliation(s)
- Grace Naswa Makokha
- Department of Gastroenterology and Metabolism, Institute of Biomedical and Health Science, Hiroshima, Japan
- Liver Research Project Center, Hiroshima, Japan
| | - Hiromi Abe-Chayama
- Department of Gastroenterology and Metabolism, Institute of Biomedical and Health Science, Hiroshima, Japan
- Liver Research Project Center, Hiroshima, Japan
- Center for Medical Specialist Graduate Education and Research, Hiroshima, Japan
| | - Sajeda Chowdhury
- Department of Gastroenterology and Metabolism, Institute of Biomedical and Health Science, Hiroshima, Japan
- Liver Research Project Center, Hiroshima, Japan
| | - C Nelson Hayes
- Department of Gastroenterology and Metabolism, Institute of Biomedical and Health Science, Hiroshima, Japan
- Liver Research Project Center, Hiroshima, Japan
| | - Masataka Tsuge
- Department of Gastroenterology and Metabolism, Institute of Biomedical and Health Science, Hiroshima, Japan
- Liver Research Project Center, Hiroshima, Japan
- Natural Science Center for Basic Research and Development, Hiroshima, Japan
| | - Tadahiko Yoshima
- Liver Research Project Center, Hiroshima, Japan
- Laboratory for Digestive Diseases, RIKEN Center for Integrative Medical Sciences Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima-shi, 734-8551, Japan
| | - Yuji Ishida
- PhoenixBio Co., Ltd., 3-4-1 Kagamiyama, Higashihiroshima, 739-0046, Japan
| | - Yizhou Zhang
- Department of Gastroenterology and Metabolism, Institute of Biomedical and Health Science, Hiroshima, Japan
- Liver Research Project Center, Hiroshima, Japan
| | - Takuro Uchida
- Department of Gastroenterology and Metabolism, Institute of Biomedical and Health Science, Hiroshima, Japan
- Liver Research Project Center, Hiroshima, Japan
| | - Chise Tateno
- PhoenixBio Co., Ltd., 3-4-1 Kagamiyama, Higashihiroshima, 739-0046, Japan
| | - Rie Akiyama
- Department of Gastroenterology and Metabolism, Institute of Biomedical and Health Science, Hiroshima, Japan
- Liver Research Project Center, Hiroshima, Japan
| | - Kazuaki Chayama
- Department of Gastroenterology and Metabolism, Institute of Biomedical and Health Science, Hiroshima, Japan.
- Liver Research Project Center, Hiroshima, Japan.
- Laboratory for Digestive Diseases, RIKEN Center for Integrative Medical Sciences Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima-shi, 734-8551, Japan.
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74
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French RL, Grese ZR, Aligireddy H, Dhavale DD, Reeb AN, Kedia N, Kotzbauer PT, Bieschke J, Ayala YM. Detection of TAR DNA-binding protein 43 (TDP-43) oligomers as initial intermediate species during aggregate formation. J Biol Chem 2019; 294:6696-6709. [PMID: 30824544 PMCID: PMC6497947 DOI: 10.1074/jbc.ra118.005889] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 02/27/2019] [Indexed: 12/14/2022] Open
Abstract
Aggregates of the RNA-binding protein TDP-43 (TAR DNA-binding protein) are a hallmark of the overlapping neurodegenerative disorders amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. The process of TDP-43 aggregation remains poorly understood, and whether it includes formation of intermediate complexes is unknown. Here, we analyzed aggregates derived from purified TDP-43 under semidenaturing conditions, identifying distinct oligomeric complexes at the initial time points before the formation of large aggregates. We found that this early oligomerization stage is primarily driven by TDP-43's RNA-binding region. Specific binding to GU-rich RNA strongly inhibited both TDP-43 oligomerization and aggregation, suggesting that RNA interactions are critical for maintaining TDP-43 solubility. Moreover, we analyzed TDP-43 liquid-liquid phase separation and detected similar detergent-resistant oligomers upon maturation of liquid droplets into solid-like fibrils. These results strongly suggest that the oligomers form during the early steps of TDP-43 misfolding. Importantly, the ALS-linked TDP-43 mutations A315T and M337V significantly accelerate aggregation, rapidly decreasing the monomeric population and shortening the oligomeric phase. We also show that aggregates generated from purified TDP-43 seed intracellular aggregation detected by established TDP-43 pathology markers. Remarkably, cytoplasmic aggregate seeding was detected earlier for the A315T and M337V variants and was 50% more widespread than for WT TDP-43 aggregates. We provide evidence for an initial step of TDP-43 self-assembly into intermediate oligomeric complexes, whereby these complexes may provide a scaffold for aggregation. This process is altered by ALS-linked mutations, underscoring the role of perturbations in TDP-43 homeostasis in protein aggregation and ALS-FTD pathogenesis.
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Affiliation(s)
- Rachel L French
- From the Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University, St. Louis, Missouri 63103
| | - Zachary R Grese
- From the Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University, St. Louis, Missouri 63103
| | - Himani Aligireddy
- From the Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University, St. Louis, Missouri 63103
| | - Dhruva D Dhavale
- the Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63110, and
| | - Ashley N Reeb
- From the Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University, St. Louis, Missouri 63103
| | - Niraja Kedia
- the MRC Prion Unit, University College London, London W1W 7FF, United Kingdom
| | - Paul T Kotzbauer
- the Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63110, and
| | - Jan Bieschke
- the MRC Prion Unit, University College London, London W1W 7FF, United Kingdom
| | - Yuna M Ayala
- From the Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University, St. Louis, Missouri 63103,
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75
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Mitra J, Guerrero EN, Hegde PM, Liachko NF, Wang H, Vasquez V, Gao J, Pandey A, Taylor JP, Kraemer BC, Wu P, Boldogh I, Garruto RM, Mitra S, Rao KS, Hegde ML. Motor neuron disease-associated loss of nuclear TDP-43 is linked to DNA double-strand break repair defects. Proc Natl Acad Sci U S A 2019; 116:4696-4705. [PMID: 30770445 PMCID: PMC6410842 DOI: 10.1073/pnas.1818415116] [Citation(s) in RCA: 184] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Genome damage and their defective repair have been etiologically linked to degenerating neurons in many subtypes of amyotrophic lateral sclerosis (ALS) patients; however, the specific mechanisms remain enigmatic. The majority of sporadic ALS patients feature abnormalities in the transactivation response DNA-binding protein of 43 kDa (TDP-43), whose nucleo-cytoplasmic mislocalization is characteristically observed in spinal motor neurons. While emerging evidence suggests involvement of other RNA/DNA binding proteins, like FUS in DNA damage response (DDR), the role of TDP-43 in DDR has not been investigated. Here, we report that TDP-43 is a critical component of the nonhomologous end joining (NHEJ)-mediated DNA double-strand break (DSB) repair pathway. TDP-43 is rapidly recruited at DSB sites to stably interact with DDR and NHEJ factors, specifically acting as a scaffold for the recruitment of break-sealing XRCC4-DNA ligase 4 complex at DSB sites in induced pluripotent stem cell-derived motor neurons. shRNA or CRISPR/Cas9-mediated conditional depletion of TDP-43 markedly increases accumulation of genomic DSBs by impairing NHEJ repair, and thereby, sensitizing neurons to DSB stress. Finally, TDP-43 pathology strongly correlates with DSB repair defects, and damage accumulation in the neuronal genomes of sporadic ALS patients and in Caenorhabditis elegans mutant with TDP-1 loss-of-function. Our findings thus link TDP-43 pathology to impaired DSB repair and persistent DDR signaling in motor neuron disease, and suggest that DSB repair-targeted therapies may ameliorate TDP-43 toxicity-induced genome instability in motor neuron disease.
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Affiliation(s)
- Joy Mitra
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030
| | - Erika N Guerrero
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030
- Center for Neuroscience, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, City of Knowledge, Panama, Republic of Panama
- Department of Biotechnology, Acharya Nagarjuna University, Guntur 522510, India
| | - Pavana M Hegde
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030
| | - Nicole F Liachko
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, WA 98104
| | - Haibo Wang
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030
- Institute of Academic Medicine, Houston Methodist Research Institute, Houston, TX 77030
| | - Velmarini Vasquez
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030
- Center for Neuroscience, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, City of Knowledge, Panama, Republic of Panama
- Department of Biotechnology, Acharya Nagarjuna University, Guntur 522510, India
| | - Junling Gao
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555
| | - Arvind Pandey
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030
| | - J Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN 38105
- Howard Hughes Medical Institute, St. Jude Children's Research Hospital, Chevy Chase, MD 20815
| | - Brian C Kraemer
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108
- Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington, Seattle, WA 98104
| | - Ping Wu
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555
| | - Istvan Boldogh
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555
| | - Ralph M Garruto
- Department of Anthropology, Binghamton University, State University of New York, Binghamton, NY 13902;
- Department of Biological Sciences, Binghamton University, State University of New York, Binghamton, NY 13902
| | - Sankar Mitra
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030
- Department of Radiation Oncology, Weill Medical College, New York, NY 10065
| | - K S Rao
- Center for Neuroscience, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, City of Knowledge, Panama, Republic of Panama
| | - Muralidhar L Hegde
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030;
- Institute of Academic Medicine, Houston Methodist Research Institute, Houston, TX 77030
- Department of Radiation Oncology, Weill Medical College, New York, NY 10065
- Houston Methodist Neurological Institute, Houston Methodist Research Institute, Houston, TX 77030
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76
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Bose P, Armstrong GAB, Drapeau P. Neuromuscular junction abnormalities in a zebrafish loss-of-function model of TDP-43. J Neurophysiol 2018; 121:285-297. [PMID: 30461368 DOI: 10.1152/jn.00265.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Almost 90% of amyotrophic lateral sclerosis (ALS) cases are characterized by the presence of aggregates of insoluble, misfolded cytoplasmic TAR DNA binding protein of 43 kDa (TDP-43). Distal axonopathy with impaired neuromuscular junctions (NMJs) before motor neuron degeneration or clinical onset of symptoms has been hypothesized as an early pathology in ALS. However, synaptic defects at the NMJ caused by TDP-43 mutations have not been characterized. In this study, we examined a previously reported zebrafish line expressing the tardbpY220X/Y220X variant, which results in an unstable and degraded protein. These tardbp-/- larvae, however, mature normally due to the upregulated expression of an alternative splice variant of the tardbp paralog tardbp-like, or tardbpl. We generated a mutant line with a CRISPR/Cas9-mediated 5-base pair deletion encompassing the ATG start codon of tardbpl and in-crossed these with tardbp-/- mutants to obtain tardbp-/- and tardbpl-/- double mutants, herein referred to as hom/hom. We subsequently characterized morphological, coiling, locomotor, synaptic, and NMJ structural abnormalities in the hom/hom mutants and in their genotypic controls. We observed that hom/hom mutants displayed gross morphological defects, early lethality, reduced locomotor function, aberrant quantal transmission, and perturbed synapse architecture at the NMJ. We further employed pharmacological manipulations in an effort to rescue phenotypic defects and observed that tardbp+/-; tardbpl-/- (herein referred to as het/hom) mutants, but not hom/hom mutants, were sensitive to chronic treatments of BAY K 8644, an L-type calcium channel agonist. This result highlights the importance of partial vs. complete loss of allelic functions of TDP-43. NEW & NOTEWORTHY This study highlights the importance of partial vs. complete loss of allelic functions of TDP-43 in a zebrafish loss of function model, thus making it an attractive tool for drug screening approaches.
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Affiliation(s)
- Poulomee Bose
- Department of Neuroscience, Centre de Recherche du Centre Hospitalier de l'Université de Montréal , Montreal, Quebec , Canada
| | - Gary A B Armstrong
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University , Montreal, Quebec , Canada
| | - Pierre Drapeau
- Department of Neuroscience, Centre de Recherche du Centre Hospitalier de l'Université de Montréal , Montreal, Quebec , Canada
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77
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Lee YC, Huang WC, Lin JH, Kao TJ, Lin HC, Lee KH, Lin HC, Shen CKJ, Chang WC, Huang CC. Znf179 E3 ligase-mediated TDP-43 polyubiquitination is involved in TDP-43- ubiquitinated inclusions (UBI) (+)-related neurodegenerative pathology. J Biomed Sci 2018; 25:76. [PMID: 30404641 PMCID: PMC6223059 DOI: 10.1186/s12929-018-0479-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 10/24/2018] [Indexed: 12/13/2022] Open
Abstract
Background The brain predominantly expressed RING finger protein, Znf179, is known to be important for embryonic neuronal differentiation during brain development. Downregulation of Znf179 has been observed in motor neurons of adult mouse models for amyotrophic lateral sclerosis (ALS), yet the molecular function of Znf179 in neurodegeneration has never been previously described. Znf179 contains the classical C3HC4 RING finger domain, and numerous proteins containing C3HC4 RING finger domain act as E3 ubiquitin ligases. Hence, we are interested to identify whether Znf179 possesses E3 ligase activity and its role in ALS neuropathy. Methods We used in vivo and in vitro ubiquitination assay to examine the E3 ligase autoubiquitination activity of Znf179 and its effect on 26S proteasome activity. To search for the candidate substrates of Znf179, we immunoprecipitated Znf179 and subjected to mass spectrometry (MS) analysis to identify its interacting proteins. We found that ALS/ FTLD-U (frontotemporal lobar degeneration (FTLD) with ubiquitin inclusions)-related neurodegenerative TDP-43 protein is the E3 ligase substrate of Znf179. To further clarify the role of E3 ubiquitin ligase Znf179 in neurodegenerative TDP-43-UBI (ubiquitinated inclusions) (+) proteinopathy, the effect of Znf179-mediated TDP-43 polyubiquitination on TDP-43 protein stability, aggregate formation and nucleus/cytoplasm mislocalization were evaluated in vitro cell culture system and in vivo animal model. Results Here we report that Znf179 is a RING E3 ubiquitin ligase which possesses autoubiquitination feature and regulates 26S proteasome activity through modulating the protein expression levels of 19S/20S proteasome subunits. Our immunoprecipitation assay and MS analysis results revealed that the neuropathological TDP-43 protein is one of its E3 ligase substrate. Znf179 interactes with TDP-43 protein and mediates polyubiquitination of TDP-43 in vitro and in vivo. In neurodegenerative TDP-43 proteinopathy, we found that Znf179-mediated polyubiquitination of TDP-43 accelerates its protein turnover rate and attenuates insoluble pathologic TDP-43 aggregates, while knockout of Znf179 in mouse brain results in accumulation of insoluble TDP-43 and cytosolic TDP-43 inclusions in cortex, hippocampus and midbrain regions. Conclusions Here we unveil the important role for the novel E3 ligase Znf179 in TDP-43-mediated neuropathy, and provide a potential therapeutic strategy for combating ALS/ FTLD-U neurodegenerative pathologies. Electronic supplementary material The online version of this article (10.1186/s12929-018-0479-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yi-Chao Lee
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology/Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, 115, Taiwan
| | - Wan-Chen Huang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 115, Taiwan
| | - Jiann-Her Lin
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology/Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, 115, Taiwan.,Department of Neurosurgery, Taipei Medical University, Taipei, Taiwan.,Division of Neurosurgery, Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Tzu-Jen Kao
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology/Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, 115, Taiwan
| | - Hui-Ching Lin
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, 112, Taiwan
| | - Kuen-Haur Lee
- Graduate Institute of Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, 115, Taiwan
| | - Hsin-Chuan Lin
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan
| | | | - Wen-Chang Chang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan
| | - Chi-Chen Huang
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology/Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, 115, Taiwan.
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78
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Standardized phytotherapic extracts rescue anomalous locomotion and electrophysiological responses of TDP-43 Drosophila melanogaster model of ALS. Sci Rep 2018; 8:16002. [PMID: 30375462 PMCID: PMC6207707 DOI: 10.1038/s41598-018-34452-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 10/18/2018] [Indexed: 12/12/2022] Open
Abstract
Findings from studies using animal models expressing amyotrophic lateral sclerosis (ALS) mutations in RNA-binding proteins, such as Transactive Response DNA-binding protein-43 (TDP-43), indicate that this protein, which is involved in multiple functions, including transcriptional regulation and pre-mRNA splicing, represents a key candidate in ALS development. This study focuses on characterizing, in a Drosophila genetic model of ALS (TDP-43), the effects of Mucuna pruriens (Mpe) and Withania somnifera (Wse). Electrophysiological and behavioural data in TDP-43 mutant flies revealed anomalous locomotion (i.e. impaired climbing with unexpected hyperactivity) and sleep dysregulation. These features, in agreement with previous findings with a different ALS model, were at least partially, rescued by treatment with Mpe and Wse. In addition, electrophysiological recordings from dorsal longitudinal muscle fibers and behavioral observations of TDP-43 flies exposed to the volatile anaesthetics, diethyl ether or chloroform, showed paradoxical responses, which were normalized upon Mpe or Wse treatment. Hence, given the involvement of some potassium channels in the effects of anaesthetics, our results also hint toward a possible dysregulation of some potassium channels in the ALS-TDP-43 Drosophila model, that might shed new light on future therapeutic strategies pertaining to ALS.
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79
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Zacco E, Martin SR, Thorogate R, Pastore A. The RNA-Recognition Motifs of TAR DNA-Binding Protein 43 May Play a Role in the Aberrant Self-Assembly of the Protein. Front Mol Neurosci 2018; 11:372. [PMID: 30356856 PMCID: PMC6190850 DOI: 10.3389/fnmol.2018.00372] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/20/2018] [Indexed: 12/12/2022] Open
Abstract
The TAR DNA-binding protein 43 (TDP-43) is a nucleic acid-binding protein implicated in gene regulation and RNA processing and shuffling. It is a ribonuclear protein that carries out most of its functions by binding specific nucleic acid sequences with its two RNA-recognition motifs, RRM1 and RRM2. TDP-43 has been identified in toxic cytosolic inclusions in neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U). The unstructured C-terminus has prion-like behavior and has been considered the driver of the aberrant self-assembly of TDP-43. In this work, we set out to test the hypothesis that the RNA-binding domains could also play a role in protein aggregation. This knowledge could be of important value for understanding TDP-43 aberrant, disease-leading behavior and, in the future, inform the design of small molecules that could prevent or slow down protein aggregation by exploiting the RNA-binding properties of the protein. We investigated the behavior of the two tandem RRM domains separately and linked together and studied their self-assembly properties and RNA-binding ability with a number of biophysical techniques. The picture that emerges from our study suggests that this region of the protein plays an important and so far unexplored role in the aggregation of this protein.
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Affiliation(s)
- Elsa Zacco
- UK Dementia Research Institute, King's College London, London, United Kingdom.,The Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | | | - Richard Thorogate
- London Centre for Nanotechnology, Faculty of Mathematical and Physical Sciences, University College London, London, United Kingdom
| | - Annalisa Pastore
- UK Dementia Research Institute, King's College London, London, United Kingdom.,The Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
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80
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Miguel L, Avequin T, Pons M, Frebourg T, Campion D, Lecourtois M. FTLD/ALS-linked TDP-43 mutations do not alter TDP-43's ability to self-regulate its expression in Drosophila. Brain Res 2018; 1695:1-9. [PMID: 29778779 DOI: 10.1016/j.brainres.2018.05.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 05/16/2018] [Accepted: 05/17/2018] [Indexed: 10/16/2022]
Abstract
TDP-43 is a major disease-causing protein in amyotrophic lateral sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD). Today, >50 missense mutations in the TARDBP/TDP-43 gene have been described in patients with FTLD/ALS. However, the functional consequences of FTLD/ALS-linked TDP-43 mutations are not fully elucidated. In the physiological state, TDP-43 expression is tightly regulated through an autoregulatory negative feedback loop. Maintaining normal TDP-43 protein levels is critical for proper physiological functions of the cells. In the present study, we investigated whether the FTLD/ALS-associated mutations could interfere with TDP-43 protein's capacity to modulate its own protein levels using Drosophila as an experimental model. Our data show that FTLD/ALS-associated mutant proteins regulate TDP-43 production with the same efficiency as the wild-type form of the protein. Thus, FTLD/ALS-linked TDP-43 mutations do not alter TDP-43's ability to self-regulate its expression and consequently of the homeostasis of TDP-43 protein levels.
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Affiliation(s)
- Laetitia Miguel
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France
| | - Tracey Avequin
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France
| | - Marine Pons
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France
| | - Thierry Frebourg
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France; Department of Genetics, Rouen University Hospital, 76301 Rouen, France
| | - Dominique Campion
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France; Centre Hospitalier du Rouvray, Sotteville-Lès-Rouen, France
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81
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Saldi TK, Gonzales P, Garrido-Lecca A, Dostal V, Roberts CM, Petrucelli L, Link CD. The Caenorhabditis elegans Ortholog of TDP-43 Regulates the Chromatin Localization of the Heterochromatin Protein 1 Homolog HPL-2. Mol Cell Biol 2018; 38:e00668-17. [PMID: 29760282 PMCID: PMC6048318 DOI: 10.1128/mcb.00668-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 02/04/2018] [Accepted: 05/01/2018] [Indexed: 12/13/2022] Open
Abstract
TDP-1 is the Caenorhabditis elegans ortholog of mammalian TDP-43, which is strongly implicated in the etiology of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). We discovered that deletion of the tdp-1 gene results in enhanced nuclear RNA interference (RNAi). As nuclear RNAi in C. elegans involves chromatin changes moderated by HPL-2, a homolog of heterochromatin protein 1 (HP1), we investigated the interaction of TDP-1 and HPL-2. We found that TDP-1 and HPL-2 interact directly and that loss of TDP-1 dramatically alters the chromatin association of HPL-2. We showed previously that deletion of the tdp-1 gene results in transcriptional alterations and the accumulation of double-stranded RNA (dsRNA). These molecular changes are replicated in an hpl-2 deletion strain, consistent with HPL-2 acting in consort with TDP-1 to modulate these aspects of RNA metabolism. Our observations identify novel mechanisms by which HP1 homologs can be recruited to chromatin and by which nuclear depletion of human TDP-43 may lead to changes in RNA metabolism that are relevant to disease.
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Affiliation(s)
- Tassa K Saldi
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Patrick Gonzales
- Integrative Physiology, University of Colorado, Boulder, Colorado, USA
| | - Alfonso Garrido-Lecca
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Vishantie Dostal
- Integrative Physiology, University of Colorado, Boulder, Colorado, USA
| | | | | | - Christopher D Link
- Integrative Physiology, University of Colorado, Boulder, Colorado, USA
- Institute for Behavioral Genetics, University of Colorado, Boulder, Colorado, USA
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82
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McClory SP, Lynch KW, Ling JP. HnRNP L represses cryptic exons. RNA (NEW YORK, N.Y.) 2018; 24:761-768. [PMID: 29581412 PMCID: PMC5959245 DOI: 10.1261/rna.065508.117] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 03/21/2018] [Indexed: 05/14/2023]
Abstract
The fidelity of RNA splicing is regulated by a network of splicing enhancers and repressors, although the rules that govern this process are not yet fully understood. One mechanism that contributes to splicing fidelity is the repression of nonconserved cryptic exons by splicing factors that recognize dinucleotide repeats. We previously identified that TDP-43 and PTBP1/PTBP2 are capable of repressing cryptic exons utilizing UG and CU repeats, respectively. Here we demonstrate that hnRNP L (HNRNPL) also represses cryptic exons by utilizing exonic CA repeats, particularly near the 5'SS. We hypothesize that hnRNP L regulates CA repeat repression for both cryptic exon repression and developmental processes such as T cell differentiation.
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Affiliation(s)
- Sean P McClory
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059, USA
| | - Kristen W Lynch
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059, USA
| | - Jonathan P Ling
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196, USA
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83
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Vogt MA, Ehsaei Z, Knuckles P, Higginbottom A, Helmbrecht MS, Kunath T, Eggan K, Williams LA, Shaw PJ, Wurst W, Floss T, Huber AB, Taylor V. TDP-43 induces p53-mediated cell death of cortical progenitors and immature neurons. Sci Rep 2018; 8:8097. [PMID: 29802307 PMCID: PMC5970242 DOI: 10.1038/s41598-018-26397-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 05/09/2018] [Indexed: 12/13/2022] Open
Abstract
TAR DNA-binding protein 43 (TDP-43) is a key player in neurodegenerative diseases including frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Accumulation of TDP-43 is associated with neuronal death in the brain. How increased and disease-causing mutant forms of TDP-43 induce cell death remains unclear. Here we addressed the role of TDP-43 during neural development and show that reduced TDP-43 causes defects in neural stem/progenitor cell proliferation but not cell death. However, overexpression of wild type and TDP-43A315T proteins induce p53-dependent apoptosis of neural stem/progenitors and human induced pluripotent cell (iPS)-derived immature cortical neurons. We show that TDP-43 induces expression of the proapoptotic BH3-only genes Bbc3 and Bax, and that p53 inhibition rescues TDP-43 induced cell death of embryonic mouse, and human cortical neurons, including those derived from TDP-43G298S ALS patient iPS cells. Hence, an increase in wild type and mutant TDP-43 induces p53-dependent cell death in neural progenitors developing neurons and this can be rescued. These findings may have important implications for accumulated or mutant TDP-43 induced neurodegenerative diseases.
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Affiliation(s)
- Miriam A Vogt
- Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058, Basel, Switzerland.,Ludwig-Maximilians University Munich, Feodor-Lynen-Strasse 17, 81377, München, Germany
| | - Zahra Ehsaei
- Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058, Basel, Switzerland
| | - Philip Knuckles
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058, Basel, Switzerland
| | - Adrian Higginbottom
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385A Glossop Road, Sheffield, S10 2HQ, UK
| | | | - Tilo Kunath
- MRC Centre for Regenerative Medicine, The University of Edinburgh, 5 Little France Drive, Edinburgh, EH16 4UU, UK
| | - Kevin Eggan
- Harvard Stem Cell Institute, Harvard University, Howard Hughes Medical Institute, 7 Divinity Avenue, Cambridge, MA, 02138, USA
| | - Luis A Williams
- Harvard Stem Cell Institute, Harvard University, Howard Hughes Medical Institute, 7 Divinity Avenue, Cambridge, MA, 02138, USA
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, 385A Glossop Road, Sheffield, S10 2HQ, UK
| | - Wolfgang Wurst
- Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
| | - Thomas Floss
- Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
| | - Andrea B Huber
- Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany.,ETH Zurich, Department of Biosystems Science and Engineering, Mattenstrasse 26, 4058, Basel, Switzerland
| | - Verdon Taylor
- Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058, Basel, Switzerland.
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84
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A Docosahexaenoic Acid-Derived Pro-resolving Agent, Maresin 1, Protects Motor Neuron Cells Death. Neurochem Res 2018; 43:1413-1423. [DOI: 10.1007/s11064-018-2556-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 05/10/2018] [Accepted: 05/17/2018] [Indexed: 12/19/2022]
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85
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TDP-43 regulation of stress granule dynamics in neurodegenerative disease-relevant cell types. Sci Rep 2018; 8:7551. [PMID: 29765078 PMCID: PMC5953947 DOI: 10.1038/s41598-018-25767-0] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 04/27/2018] [Indexed: 12/24/2022] Open
Abstract
Stress granules (SGs) are cytoplasmic foci that form in response to various external stimuli and are essential to cell survival following stress. SGs are studied in several diseases, including ALS and FTD, which involve the degeneration of motor and cortical neurons, respectively, and are now realized to be linked pathogenically by TDP-43, originally discovered as a component of ubiquitin-positive aggregates within patients’ neurons and some glial cells. So far, studies to undercover the role of TDP-43 in SGs have used primarily transformed cell lines, and thus rely on the extrapolation of the mechanisms to cell types affected in ALS/FTD, potentially masking cell specific effects. Here, we investigate SG dynamics in primary motor and cortical neurons as well as astrocytes. Our data suggest a cell and stress specificity and demonstrate a requirement for TDP-43 for efficient SG dynamics. In addition, based on our in vitro approach, our data suggest that aging may be an important modifier of SG dynamics which could have relevance to the initiation and/or progression of age-related neurodegenerative diseases.
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86
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Langellotti S, Romano G, Feiguin F, Baralle FE, Romano M. RhoGAPp190: A potential player in tbph-mediated neurodegeneration in Drosophila. PLoS One 2018; 13:e0195845. [PMID: 29652933 PMCID: PMC5898758 DOI: 10.1371/journal.pone.0195845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 04/01/2018] [Indexed: 12/13/2022] Open
Abstract
TDP-43 is an ubiquitous and highly conserved ribonucleoprotein involved in several cellular processes including pre-mRNA splicing, transcription, mRNA stability and transport. Notwithstanding the evidence of TDP-43 involvement in the pathogenesis of different neurodegenerative disorders (i.e. ALS and FTLD), the underlying mechanisms are still unclear. Given the high degree of functional similarity between the human and fly orthologs of TDP-43, Drosophila melanogaster is a simple and useful model to study the pathophysiological role of this protein in vivo. It has been demonstrated that the depletion of the TDP-43 fly ortholog (tbph) induces deficient locomotive behaviors and reduces life span and anatomical defects at the neuromuscular junction. In this study, using the known binding specificity of TDP-43/tbph for (UG) repeated sequences, we performed a bioinformatic screening for fly genes with at least 6 (TG) repeats in a row within the 3'-UTR regions in order to identify the genes that might be regulated by this factor. Among these genes, we were able to identify RhoGAPp190 as a potential target of the tbph-mediated neurodegeneration. RhoGAPp190 is a negative regulator of Drosophila RhoA, a GTPase protein implicated in the fine modulation of critical cellular processes including axon branch stability and motor axon defasciculation at muscle level and cognitive processes. We were able to demonstrate that the RhoGAPp190 expression is upregulated in a tbph-null fly model, providing evidence that this deregulation is associated to tbph silencing. Our results introduce RhoGAPp190 as a novel potential mediator in the complex scenario of events resulting from in vivo tbph loss-of-function.
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Affiliation(s)
- Simona Langellotti
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Giulia Romano
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Fabian Feiguin
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | | | - Maurizio Romano
- Department of Life Sciences, University of Trieste, Trieste, Italy
- * E-mail:
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87
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Kitamura A, Shibasaki A, Takeda K, Suno R, Kinjo M. Analysis of the substrate recognition state of TDP-43 to single-stranded DNA using fluorescence correlation spectroscopy. Biochem Biophys Rep 2018; 14:58-63. [PMID: 29872735 PMCID: PMC5986658 DOI: 10.1016/j.bbrep.2018.03.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 03/28/2018] [Accepted: 03/30/2018] [Indexed: 11/15/2022] Open
Abstract
Normal function and abnormal aggregation of transactivation response (TAR) DNA/RNA-binding protein 43 kDa (TDP-43) are directly associated with the lethal genetic diseases: cystic fibrosis, amyotrophic lateral sclerosis (ALS), and frontotemporal lobar degeneration (FTLD). The binding of TDP-43 to single-stranded DNA (ssDNA) or RNA is involved in transcriptional repression, regulation of RNA splicing, and RNA stabilization. Equilibrium dissociation constants (Kd) of TDP-43 and ssDNA or RNA have been determined using various methods; however, methods that can measure Kd with high sensitivity in a short time using a small amount of TDP-43 in solution would be advantageous. Here, in order to determine the Kd of TDP-43 and fluorescence-labeled ssDNA as well as the binding stoichiometry, we use fluorescence correlation spectroscopy (FCS), which detects the slowed diffusion of molecular interactions in solution with single-molecule sensitivity, in addition to electrophoretic mobility shift assay (EMSA). Using tandem affinity chromatography of TDP-43 dually tagged with glutathione-S-transferase and poly-histidine tags, highly purified protein was obtained. FCS successfully detected specific interaction between purified TDP-43 and TG ssDNA repeats, with a Kd in the nanomolar range. The Kd of the TDP-43 mutant was not different from the wild type, although mutant oligomers, which did not bind ssDNA, were observed. Analysis of the fluorescence brightness per dimerized TDP-43/ssDNA complex was used to evaluate their binding stoichiometry. The results suggest that an assay combining FCS and EMSA can precisely analyze ssDNA recognition mechanisms, and that FCS may be applied for the rapid and quantitative determination of the interaction strength between TDP-43 and ssDNA or RNA. These methods will aid in the elucidation of the substrate recognition mechanism of ALS- and FTLD-associated variants of TDP-43. The dissociation constant (Kd) of TDP-43 and single stranded DNA was determined. Wild type and amyotrophic lateral sclerosis mutant TDP-43 had similar Kd values. Stoichiometric analysis suggests that TDP-43 dimers bind to two molecules of ssDNA.
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Affiliation(s)
- Akira Kitamura
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo 001-0021, Japan
| | - Ai Shibasaki
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo 001-0021, Japan
| | - Kayo Takeda
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo 001-0021, Japan
| | - Ryoji Suno
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto 605-8501, Japan
| | - Masataka Kinjo
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo 001-0021, Japan
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88
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Gao J, Wang L, Huntley ML, Perry G, Wang X. Pathomechanisms of TDP-43 in neurodegeneration. J Neurochem 2018; 146:10.1111/jnc.14327. [PMID: 29486049 PMCID: PMC6110993 DOI: 10.1111/jnc.14327] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 02/08/2018] [Accepted: 02/20/2018] [Indexed: 12/11/2022]
Abstract
Neurodegeneration, a term that refers to the progressive loss of structure and function of neurons, is a feature of many neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). There is no cure or treatment available that can prevent or reverse neurodegenerative conditions. The causes of neurodegeneration in these diseases remain largely unknown; yet, an extremely small proportion of these devastating diseases are associated with genetic mutations in proteins involved in a wide range of cellular pathways and processes. Over the past decade, it has become increasingly clear that the most notable neurodegenerative diseases, such as ALS, FTLD, and AD, share a common prominent pathological feature known as TAR DNA-binding protein 43 (TDP-43) proteinopathy, which is usually characterized by the presence of aberrant phosphorylation, ubiquitination, cleavage and/or nuclear depletion of TDP-43 in neurons and glial cells. The role of TDP-43 as a neurotoxicity trigger has been well documented in different in vitro and in vivo experimental models. As such, the investigation of TDP-43 pathomechanisms in various major neurodegenerative diseases is on the rise. Here, after a discussion of stages of TDP-43 proteinopathy during disease progression in various major neurodegenerative diseases, we review previous and most recent studies about the potential pathomechanisms with a particular emphasis on ALS, FTLD, and AD, and discuss the possibility of targeting TDP-43 as a common therapeutic approach to treat neurodegenerative diseases.
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Affiliation(s)
- Ju Gao
- Departments of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Luwen Wang
- Departments of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Mikayla L. Huntley
- Departments of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - George Perry
- College of Sciences, University of Texas at San Antonio, San Antonio, Texas, USA
| | - Xinglong Wang
- Departments of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
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89
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Wang A, Conicella AE, Schmidt HB, Martin EW, Rhoads SN, Reeb AN, Nourse A, Ramirez Montero D, Ryan VH, Rohatgi R, Shewmaker F, Naik MT, Mittag T, Ayala YM, Fawzi NL. A single N-terminal phosphomimic disrupts TDP-43 polymerization, phase separation, and RNA splicing. EMBO J 2018; 37:embj.201797452. [PMID: 29438978 PMCID: PMC5830921 DOI: 10.15252/embj.201797452] [Citation(s) in RCA: 252] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Revised: 10/20/2017] [Accepted: 12/30/2017] [Indexed: 12/12/2022] Open
Abstract
TDP‐43 is an RNA‐binding protein active in splicing that concentrates into membraneless ribonucleoprotein granules and forms aggregates in amyotrophic lateral sclerosis (ALS) and Alzheimer's disease. Although best known for its predominantly disordered C‐terminal domain which mediates ALS inclusions, TDP‐43 has a globular N‐terminal domain (NTD). Here, we show that TDP‐43 NTD assembles into head‐to‐tail linear chains and that phosphomimetic substitution at S48 disrupts TDP‐43 polymeric assembly, discourages liquid–liquid phase separation (LLPS) in vitro, fluidizes liquid–liquid phase separated nuclear TDP‐43 reporter constructs in cells, and disrupts RNA splicing activity. Finally, we present the solution NMR structure of a head‐to‐tail NTD dimer comprised of two engineered variants that allow saturation of the native polymerization interface while disrupting higher‐order polymerization. These data provide structural detail for the established mechanistic role of the well‐folded TDP‐43 NTD in splicing and link this function to LLPS. In addition, the fusion‐tag solubilized, recombinant form of TDP‐43 full‐length protein developed here will enable future phase separation and in vitro biochemical assays on TDP‐43 function and interactions that have been hampered in the past by TDP‐43 aggregation.
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Affiliation(s)
- Ailin Wang
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI, USA
| | - Alexander E Conicella
- Graduate Program in Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
| | | | - Erik W Martin
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Shannon N Rhoads
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University, Bethesda, MD, USA
| | - Ashley N Reeb
- Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, USA
| | - Amanda Nourse
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Daniel Ramirez Montero
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI, USA
| | - Veronica H Ryan
- Neuroscience Graduate Program, Brown University, Providence, RI, USA
| | - Rajat Rohatgi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA.,Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Frank Shewmaker
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University, Bethesda, MD, USA
| | - Mandar T Naik
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI, USA
| | - Tanja Mittag
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Yuna M Ayala
- Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, USA
| | - Nicolas L Fawzi
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI, USA .,Graduate Program in Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
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90
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Bräuer S, Zimyanin V, Hermann A. Prion-like properties of disease-relevant proteins in amyotrophic lateral sclerosis. J Neural Transm (Vienna) 2018; 125:591-613. [PMID: 29417336 DOI: 10.1007/s00702-018-1851-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 01/30/2018] [Indexed: 02/07/2023]
Abstract
The hallmark of age-related neurodegenerative diseases is the appearance of cellular protein deposits and spreading of this pathology throughout the central nervous system. Growing evidence has shown the involvement and critical role of proteins with prion-like properties in the formation of these characteristic cellular aggregates. Prion-like domains of such proteins with their proposed function in the organization of membraneless organelles are prone for misfolding and promoting further aggregation. Spreading of these toxic aggregates between cells and across tissues can explain the progression of clinical phenotypes and pathology in a stereotypical manner, characteristic for almost every neurodegenerative disease. Here, we want to review the current evidence for the role of prion-like mechanisms in classical neurodegenerative diseases and ALS in particular. We will also discuss an intriguingly central role of the protein TDP-43 in the majority of cases of this devastating disease.
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Affiliation(s)
- S Bräuer
- Department of Neurology, Technische Universität Dresden, Fetscherstraße 74, 01307, Dresden, Germany
- Department of Neurology, Städtisches Klinikum Dresden, 01129, Dresden, Germany
| | - V Zimyanin
- Department of Neurology, Technische Universität Dresden, Fetscherstraße 74, 01307, Dresden, Germany
| | - A Hermann
- Department of Neurology, Technische Universität Dresden, Fetscherstraße 74, 01307, Dresden, Germany.
- Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden and German Center for Neurodegenerative Diseases (DZNE), 01307, Dresden, Germany.
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91
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Pons M, Miguel L, Miel C, Avequin T, Juge F, Frebourg T, Campion D, Lecourtois M. Splicing factors act as genetic modulators of TDP-43 production in a new autoregulatory TDP-43 Drosophila model. Hum Mol Genet 2018; 26:3396-3408. [PMID: 28854702 DOI: 10.1093/hmg/ddx229] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 06/09/2017] [Indexed: 01/24/2023] Open
Abstract
TDP-43 is a critical RNA-binding factor associated with RNA metabolism. In the physiological state, maintaining normal TDP-43 protein levels is critical for proper physiological functions of the cells. As such, TDP-43 expression is tightly regulated through an autoregulatory negative feedback loop. TDP-43 is a major disease-causing protein in Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD). Several studies argue for a pathogenic role of elevated TDP-43 levels in these disorders. Modulating the cycle of TDP-43 production might therefore provide a new therapeutic strategy. In this study, we developed a new transgenic Drosophila model mimicking the TDP-43 autoregulatory feedback loop in order to identify genetic modulators of TDP-43 protein steady-state levels in vivo. First, we showed that our TDP-43_TDPBR Drosophila model recapitulates key features of the TDP-43 autoregulatory processes previously described in mammalian and cellular models, namely alternative splicing events, differential usage of polyadenylation sites, nuclear retention of the transcript and a decrease in steady-state mRNA levels. Using this new Drosophila model, we identified several splicing factors, including SF2, Rbp1 and Sf3b1, as genetic modulators of TDP-43 production. Interestingly, our data indicate that these three RNA-binding proteins regulate TDP-43 protein production, at least in part, by controlling mRNA steady-state levels.
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Affiliation(s)
- Marine Pons
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France
| | - Laetitia Miguel
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France
| | - Camille Miel
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France
| | - Tracey Avequin
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France
| | | | - Thierry Frebourg
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France.,Department of Genetics, Rouen University Hospital, 76301 Rouen, France
| | - Dominique Campion
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France.,Centre Hospitalier du Rouvray, Sotteville-Lès-Rouen, France
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92
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Shenouda M, Zhang AB, Weichert A, Robertson J. Mechanisms Associated with TDP-43 Neurotoxicity in ALS/FTLD. ADVANCES IN NEUROBIOLOGY 2018; 20:239-263. [PMID: 29916022 DOI: 10.1007/978-3-319-89689-2_9] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The discovery of TDP-43 as a major disease protein in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) was first made in 2006. Prior to 2006 there were only 11 publications related to TDP-43, now there are over 2000, indicating the importance of TDP-43 to unraveling the complex molecular mechanisms that underpin the pathogenesis of ALS/FTLD. Subsequent to this discovery, TDP-43 pathology was also found in other neurodegenerative diseases, including Alzheimer's disease, the significance of which is still in the early stages of exploration. TDP-43 is a predominantly nuclear DNA/RNA-binding protein, one of a number of RNA-binding proteins that are now known to be linked with ALS/FTLD, including Fused in Sarcoma (FUS), heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1), and heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1). However, what sets TDP-43 apart is the vast number of cases in which TDP-43 pathology is present, providing a point of convergence, the understanding of which could lead to broadly applicable therapeutics. Here we will focus on TDP-43 in ALS/FTLD, its nuclear and cytoplasmic functions, and consequences should these functions go awry.
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Affiliation(s)
- Marc Shenouda
- Tanz Centre for Research in Neurodegenerative Diseases and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5T 2S8, Canada
| | - Ashley B Zhang
- Tanz Centre for Research in Neurodegenerative Diseases and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5T 2S8, Canada
| | - Anna Weichert
- Tanz Centre for Research in Neurodegenerative Diseases and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5T 2S8, Canada
| | - Janice Robertson
- Tanz Centre for Research in Neurodegenerative Diseases and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5T 2S8, Canada.
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93
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Abstract
Mutations in the profilin 1 (PFN1) gene have been identified as a cause of familial amyotrophic lateral sclerosis (ALS), and neuropathological studies indicate that TDP-43 is accumulated in brains of patients with PFN1 mutation. Here, we investigated the role of PFN1 mutations in the formation of prion-like abnormal TDP-43. Expression of PFN1 with pathogenic mutations resulted in the formation of cytoplasmic aggregates positive for p62 and ubiquitin, and these aggregates sequestered endogenous TDP-43. TDP-43 accumulation was facilitated in the presence of proteasome or lysosome inhibitor. Co-expression of mutant PFN1 and TDP-43 increased the levels of detergent-insoluble and phosphorylated TDP-43, and this increase required the C-terminal region of TDP-43. Moreover, detergent-insoluble fractions prepared from cells expressing ALS-linked mutant PFN1 induced seed-dependent accumulation of TDP-43. These findings indicate that expression of PFN1 mutants induces accumulation of TDP-43, and promotes conversion of normal TDP-43 into an abnormal form. These results provide new insight into the mechanisms of TDP-43 proteinopathies and other diseases associated with amyloid-like protein deposition.
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Affiliation(s)
- Yoshinori Tanaka
- a Dementia Research Project, Tokyo Metropolitan Institute of Medical Science , Tokyo , Japan
| | - Masato Hasegawa
- a Dementia Research Project, Tokyo Metropolitan Institute of Medical Science , Tokyo , Japan
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94
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Abstract
Neurodegeneration is a leading cause of death in the developed world and a natural, albeit unfortunate, consequence of longer-lived populations. Despite great demand for therapeutic intervention, it is often the case that these diseases are insufficiently understood at the basic molecular level. What little is known has prompted much hopeful speculation about a generalized mechanistic thread that ties these disparate conditions together at the subcellular level and can be exploited for broad curative benefit. In this review, we discuss a prominent theory supported by genetic and pathological changes in an array of neurodegenerative diseases: that neurons are particularly vulnerable to disruption of RNA-binding protein dosage and dynamics. Here we synthesize the progress made at the clinical, genetic, and biophysical levels and conclude that this perspective offers the most parsimonious explanation for these mysterious diseases. Where appropriate, we highlight the reciprocal benefits of cross-disciplinary collaboration between disease specialists and RNA biologists as we envision a future in which neurodegeneration declines and our understanding of the broad importance of RNA processing deepens.
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Affiliation(s)
- Erin G Conlon
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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95
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Uchino A, Ogino M, Takahashi-Fujigasaki J, Oonuma S, Kanazawa N, Kajita S, Ichinoe M, Hasegawa M, Nishiyama K, Murayama S. Pathological and immunoblot analysis of phosphorylated TDP-43 in sporadic amyotrophic lateral sclerosis with pallido-nigro-luysian degeneration. Neuropathology 2017; 38:171-178. [PMID: 28906030 DOI: 10.1111/neup.12430] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 08/21/2017] [Accepted: 08/21/2017] [Indexed: 12/12/2022]
Abstract
Transactivation response DNA-binding protein 43 kDa (TDP-43) is a key protein of sporadic amyotrophic lateral sclerosis (ALS), and phosphorylated form of TDP-43 (p-TDP-43) is a major pathological protein that accumulates in sporadic ALS. p-TDP-43 is found not only in primary motor neurons, but often propagates to non-motor systems as well. However, pallido-nigro-luysian (PNL) degeneration (PNLD) is rarely associated with ALS. We describe here a 68-year-old ALS patient presenting severe PNLD. He had difficulty walking due to poor movement of his right leg, and was diagnosed as having Parkinson's disease because of akinesia. About 2 years after onset, weakness of his left hand and leg led to a diagnosis of ALS. Tube feeding and non-invasive positive-pressure ventilation were initiated. He died of respiratory failure at the age of 71. There was no family history of either neurological disorders or dementia. Neuropathological examination revealed severe loss of neurons and gliosis in the PNL system in addition to the upper and lower motor neuron system. p-TDP-43 pathology was widespread in the PNL and motor neuron systems and also in the amygdala and hippocampus where no significant gliosis or neuronal loss was detected. Synuclein pathology was not observed in the investigated areas. Immunoblot analysis of p-TDP-43 C-terminal fragments showed a type B band pattern consistent with sporadic ALS. This is the first case of ALS with PNLD, in which p-TDP-43 distribution was widespread in the hippocampal formation (Nishihira type 2 and Brettschneider stage 4), and the type B immunoblot pattern was confirmed. Our case indicated that the PNL system can be involved in the disease process in sporadic ALS cases, although rarely. We also reviewed previous autopsy cases of ALS with PNLD to clarify the clinicopathological features.
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Affiliation(s)
- Akiko Uchino
- Department of Neurology, Kitasato Institute Hospital Kitasato University, Tokyo, Japan.,Department of Neuropathology (Brain Bank for Aging Research), Tokyo Metropolitan Geriatric Hospital & Institute of Gerontology, Tokyo, Japan
| | - Mieko Ogino
- School of Medicine, Office of Medical Education, International University of Health and Welfare, Chiba, Japan
| | - Junko Takahashi-Fujigasaki
- Department of Neuropathology (Brain Bank for Aging Research), Tokyo Metropolitan Geriatric Hospital & Institute of Gerontology, Tokyo, Japan
| | - Saori Oonuma
- Department of Neurology, Sagamihara National Hospital, Kanagawa, Japan
| | - Naomi Kanazawa
- Department of Neurology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Sabine Kajita
- Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Masaaki Ichinoe
- Department of Pathology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Masato Hasegawa
- Department of Dementia and Higher Brain Function, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kazutoshi Nishiyama
- Department of Neurology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Shigeo Murayama
- Department of Neurology and Neuropathology (Brain Bank for Aging Research), Tokyo Metropolitan Geriatric Hospital & Institute of Gerontology, Tokyo, Japan
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96
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Biology and Pathobiology of TDP-43 and Emergent Therapeutic Strategies. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a024554. [PMID: 27920024 DOI: 10.1101/cshperspect.a024554] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cytoplasmic TDP-43 mislocalization and aggregation is a pathological hallmark of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. TDP-43 is an RNA-binding protein (RBP) with a prion-like domain (PrLD) that promotes TDP-43 misfolding. PrLDs possess compositional similarity to canonical prion domains of various yeast proteins, including Sup35. Strikingly, disease-causing TDP-43 mutations reside almost exclusively in the PrLD and can enhance TDP-43 misfolding and toxicity. Another ∼70 human RBPs harbor PrLDs, including FUS, TAF15, EWSR1, hnRNPA1, and hnRNPA2, which have surfaced in the etiology of neurodegenerative diseases. Importantly, PrLDs enable RBP function and mediate phase transitions that partition functional ribonucleoprotein compartments. This PrLD activity, however, renders RBPs prone to populating deleterious oligomers or self-templating fibrils that might spread disease, and disease-linked PrLD mutations can exacerbate this risk. Several strategies have emerged to counter TDP-43 proteinopathies, including engineering enhanced protein disaggregases based on Hsp104.
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97
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Restoration of Motor Defects Caused by Loss of Drosophila TDP-43 by Expression of the Voltage-Gated Calcium Channel, Cacophony, in Central Neurons. J Neurosci 2017; 37:9486-9497. [PMID: 28847811 DOI: 10.1523/jneurosci.0554-17.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 08/17/2017] [Accepted: 08/19/2017] [Indexed: 01/08/2023] Open
Abstract
Defects in the RNA-binding protein, TDP-43, are known to cause a variety of neurodegenerative diseases, including amyotrophic lateral sclerosis and frontotemporal lobar dementia. A variety of experimental systems have shown that neurons are sensitive to TDP-43 expression levels, yet the specific functional defects resulting from TDP-43 dysregulation have not been well described. Using the Drosophila TDP-43 ortholog TBPH, we previously showed that TBPH-null animals display locomotion defects as third instar larvae. Furthermore, loss of TBPH caused a reduction in cacophony, a Type II voltage-gated calcium channel, expression and that genetically restoring cacophony in motor neurons in TBPH mutant animals was sufficient to rescue the locomotion defects. In the present study, we examined the relative contributions of neuromuscular junction physiology and the motor program to the locomotion defects and identified subsets of neurons that require cacophony expression to rescue the defects. At the neuromuscular junction, we showed mEPP amplitudes and frequency require TBPH. Cacophony expression in motor neurons rescued mEPP frequency but not mEPP amplitude. We also showed that TBPH mutants displayed reduced motor neuron bursting and coordination during crawling and restoring cacophony selectively in two pairs of cells located in the brain, the AVM001b/2b neurons, also rescued the locomotion and motor defects, but not the defects in neuromuscular junction physiology. These results suggest that the behavioral defects associated with loss of TBPH throughout the nervous system can be associated with defects in a small number of genes in a limited number of central neurons, rather than peripheral defects.SIGNIFICANCE STATEMENT TDP-43 dysfunction is a common feature in neurodegenerative diseases, including amyotrophic lateral sclerosis, frontotemporal lobar dementia, and Alzheimer's disease. Loss- and gain-of-function models have shown that neurons are sensitive to TDP-43 expression levels, but the specific defects caused by TDP-43 loss of function have not been described in detail. A Drosophila loss-of-function model displays pronounced locomotion defects that can be reversed by restoring the expression levels of a voltage-gated calcium channel, cacophony. We show these defects can be rescued by expression of cacophony in motor neurons and by expression in two pairs of neurons in the brain. These data suggest that loss of TDP-43 can disrupt the central circuitry of the CNS, opening up identification of alternative therapeutic targets for TDP-43 proteinopathies.
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98
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Jiang LL, Xue W, Hong JY, Zhang JT, Li MJ, Yu SN, He JH, Hu HY. The N-terminal dimerization is required for TDP-43 splicing activity. Sci Rep 2017; 7:6196. [PMID: 28733604 PMCID: PMC5522446 DOI: 10.1038/s41598-017-06263-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 06/08/2017] [Indexed: 12/12/2022] Open
Abstract
TDP-43 is a nuclear factor that functions in promoting pre-mRNA splicing. Deletion of the N-terminal domain (NTD) and nuclear localization signal (NLS) (i.e., TDP-35) results in mislocalization to cytoplasm and formation of inclusions. However, how the NTD functions in TDP-43 activity and proteinopathy remains largely unknown. Here, we studied the structure and function of the NTD in inclusion formation and pre-mRNA splicing of TDP-43 by using biochemical and biophysical approaches. We found that TDP-43 NTD forms a homodimer in solution in a concentration-dependent manner, and formation of intermolecular disulfide results in further tetramerization. Based on the NMR structure of TDP-43 NTD, the dimerization interface centered on Leu71 and Val72 around the β7-strand was defined by mutagenesis and size-exclusion chromatography. Cell experiments revealed that the N-terminal dimerization plays roles in protecting TDP-43 against formation of cytoplasmic inclusions and enhancing pre-mRNA splicing activity of TDP-43 in nucleus. This study may provide mechanistic insights into the physiological function of TDP-43 and its related proteinopathies.
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Affiliation(s)
- Lei-Lei Jiang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, P.R. China
| | - Wei Xue
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, P.R. China
| | - Jun-Ye Hong
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, P.R. China
| | - Jun-Ting Zhang
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai, 200433, P.R. China
| | - Min-Jun Li
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 239 Zhangheng Road, Shanghai, 201204, P.R. China
| | - Shao-Ning Yu
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai, 200433, P.R. China
| | - Jian-Hua He
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 239 Zhangheng Road, Shanghai, 201204, P.R. China
| | - Hong-Yu Hu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, P.R. China.
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99
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Mompeán M, Romano V, Pantoja-Uceda D, Stuani C, Baralle FE, Buratti E, Laurents DV. Point mutations in the N-terminal domain of transactive response DNA-binding protein 43 kDa (TDP-43) compromise its stability, dimerization, and functions. J Biol Chem 2017; 292:11992-12006. [PMID: 28566288 PMCID: PMC5512090 DOI: 10.1074/jbc.m117.775965] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 05/25/2017] [Indexed: 12/14/2022] Open
Abstract
Transactive response DNA-binding protein 43 (TDP-43) performs multiple tasks in mRNA processing, transport, and translational regulation, but it also forms aggregates implicated in amyotrophic lateral sclerosis. TDP-43's N-terminal domain (NTD) is important for these activities and dysfunctions; however, there is an open debate about whether or not it adopts a specifically folded, stable structure. Here, we studied NTD mutations designed to destabilize its structure utilizing NMR and fluorescence spectroscopies, analytical ultracentrifugation, splicing assays, and cell microscopy. The substitutions V31R and T32R abolished TDP-43 activity in splicing and aggregation processes, and even the rather mild L28A mutation severely destabilized the NTD, drastically reducing TDP-43's in vitro splicing activity and inducing aberrant localization and aggregation in cells. These findings strongly support the idea that a stably folded NTD is essential for correct TDP-43 function. The stably folded NTD also promotes dimerization, which is pertinent to the protein's activities and pathological aggregation, and we present an atomic-level structural model for the TDP-43 dimer based on NMR data. Leu-27 is evolutionarily well conserved even though it is exposed in the monomeric NTD. We found here that Leu-27 is buried in the dimer and that the L27A mutation promotes monomerization. In conclusion, our study sheds light on the structural and biological properties of the TDP-43 NTD, indicating that the NTD must be stably folded for TDP-43's physiological functions, and has implications for understanding the mechanisms promoting the pathological aggregation of this protein.
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Affiliation(s)
- Miguel Mompeán
- Instituto de Química Física "Rocasolano," Consejo Superior de Investigaciones Científicas, Serrano 119, E-28006 Madrid, Spain
| | - Valentina Romano
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, I-34149 Trieste, Italy
| | - David Pantoja-Uceda
- Instituto de Química Física "Rocasolano," Consejo Superior de Investigaciones Científicas, Serrano 119, E-28006 Madrid, Spain
| | - Cristiana Stuani
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, I-34149 Trieste, Italy
| | - Francisco E Baralle
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, I-34149 Trieste, Italy
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, I-34149 Trieste, Italy.
| | - Douglas V Laurents
- Instituto de Química Física "Rocasolano," Consejo Superior de Investigaciones Científicas, Serrano 119, E-28006 Madrid, Spain.
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100
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Hanspal MA, Dobson CM, Yerbury JJ, Kumita JR. The relevance of contact-independent cell-to-cell transfer of TDP-43 and SOD1 in amyotrophic lateral sclerosis. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2762-2771. [PMID: 28711596 PMCID: PMC6565888 DOI: 10.1016/j.bbadis.2017.07.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 06/22/2017] [Accepted: 07/11/2017] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease involving the formation of cytoplasmic aggregates by proteins including TDP-43 and SOD1, in affected cells in the central nervous system (CNS). Pathology spreads from an initial site of onset to contiguous anatomical regions. There is evidence that for disease-associated proteins, including TDP-43 and SOD1, non-native protein conformers can promote misfolding of the natively folded counterparts, and cell-to-cell transfer of pathological aggregates may underlie the spread of the disease throughout the CNS. A variety of studies have demonstrated that SOD1 is released by neuron-like cells into the surrounding culture medium, either in their free state or encapsulated in extracellular vesicles such as exosomes. Extracellular SOD1 can then be internalised by naïve cells incubated in this conditioned medium, leading to the misfolding and aggregation of endogenous intracellular SOD1; an effect that propagates over serial passages. A similar phenomenon has also been observed with other proteins associated with protein misfolding and progressive neurological disorders, including tau, α-synuclein and both mammalian and yeast prions. Conditioned media experiments using TDP-43 have been less conclusive, with evidence for this protein undergoing intercellular transfer being less straightforward. In this review, we describe the properties of TDP-43 and SOD1 and look at the evidence for their respective abilities to participate in cell-to-cell transfer via conditioned medium, and discuss how variations in the nature of cell-to-cell transfer suggests that a number of different mechanisms are involved in the spreading of pathology in ALS. Protein aggregates transfer between cells in motor neuron disease. Cell contact-independent mechanisms may be a route of transfer. SOD1 undergoes cell-to-cell transfer via conditioned medium in cell culture. It is still unclear whether TDP-43 consistently undergoes cell-to-cell transfer Differences between the two proteins may explain this observation.
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Affiliation(s)
- Maya A Hanspal
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Christopher M Dobson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Justin J Yerbury
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, NSW 2522, Australia.
| | - Janet R Kumita
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
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