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Wang X, Hu Y, Xu R. The pathogenic mechanism of TAR DNA-binding protein 43 (TDP-43) in amyotrophic lateral sclerosis. Neural Regen Res 2024; 19:800-806. [PMID: 37843214 PMCID: PMC10664110 DOI: 10.4103/1673-5374.382233] [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: 03/13/2023] [Revised: 06/19/2023] [Accepted: 07/03/2023] [Indexed: 10/17/2023] Open
Abstract
The onset of amyotrophic lateral sclerosis is usually characterized by focal death of both upper and/or lower motor neurons occurring in the motor cortex, basal ganglia, brainstem, and spinal cord, and commonly involves the muscles of the upper and/or lower extremities, and the muscles of the bulbar and/or respiratory regions. However, as the disease progresses, it affects the adjacent body regions, leading to generalized muscle weakness, occasionally along with memory, cognitive, behavioral, and language impairments; respiratory dysfunction occurs at the final stage of the disease. The disease has a complicated pathophysiology and currently, only riluzole, edaravone, and phenylbutyrate/taurursodiol are licensed to treat amyotrophic lateral sclerosis in many industrialized countries. The TAR DNA-binding protein 43 inclusions are observed in 97% of those diagnosed with amyotrophic lateral sclerosis. This review provides a preliminary overview of the potential effects of TAR DNA-binding protein 43 in the pathogenesis of amyotrophic lateral sclerosis, including the abnormalities in nucleoplasmic transport, RNA function, post-translational modification, liquid-liquid phase separation, stress granules, mitochondrial dysfunction, oxidative stress, axonal transport, protein quality control system, and non-cellular autonomous functions (e.g., glial cell functions and prion-like propagation).
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Affiliation(s)
- Xinxin Wang
- Medical College of Nanchang University, Nanchang, Jiangxi Province, China
- Department of Neurology, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, The Clinical College of Nanchang Medical College, Nanchang, Jiangxi Province, China
| | - Yushu Hu
- Medical College of Nanchang University, Nanchang, Jiangxi Province, China
- Department of Neurology, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, The Clinical College of Nanchang Medical College, Nanchang, Jiangxi Province, China
| | - Renshi Xu
- Medical College of Nanchang University, Nanchang, Jiangxi Province, China
- Department of Neurology, Jiangxi Provincial People’s Hospital, The First Affiliated Hospital of Nanchang Medical College, The Clinical College of Nanchang Medical College, Nanchang, Jiangxi Province, China
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2
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Horio T, Ishikura Y, Ohashi R, Shiina N. Regulation of RNG105/caprin1 dynamics by pathogenic cytoplasmic FUS and TDP-43 in neuronal RNA granules modulates synaptic loss. Heliyon 2023; 9:e17065. [PMID: 37484309 PMCID: PMC10361247 DOI: 10.1016/j.heliyon.2023.e17065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 05/25/2023] [Accepted: 06/06/2023] [Indexed: 07/25/2023] Open
Abstract
In neurodegenerative diseases, the condensation of FUS and TDP-43 with RNA granules in neurons is linked to pathology, including synaptic disorders. However, the effects of FUS and TDP-43 on RNA granule factors remain unclear. Here, using primary cultured neurons from the mouse cerebral cortex, we show that excess cytoplasmic FUS and TDP-43 accumulated in dendritic RNA granules, where they increased the dynamics of a scaffold protein RNG105/caprin1 and dissociated it from the granules. This coincided with reduced levels of mRNA and translation around the granules and synaptic loss in dendrites. These defects were suppressed by non-dissociable RNG105, suggesting that RNG105 dissociation mediated the defects. In contrast to the model where FUS and TDP-43 co-aggregate with RNA granule factors to repress their activity, our findings provide a novel pathogenic mechanism whereby FUS and TDP-43 dissociate RNA scaffold proteins from RNA granules which are required for local translation that regulates synapse formation.
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Affiliation(s)
- Tomoyo Horio
- Laboratory of Neuronal Cell Biology, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan
- Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8585, Japan
| | - Yui Ishikura
- Laboratory of Neuronal Cell Biology, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan
- Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8585, Japan
| | - Rie Ohashi
- Laboratory of Neuronal Cell Biology, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan
- Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8585, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan
- Life Science Research Center, University of Toyama, Toyama, Toyama 930-0194, Japan
| | - Nobuyuki Shiina
- Laboratory of Neuronal Cell Biology, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan
- Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8585, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan
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3
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Duan G, Li Y, Ye M, Liu H, Wang N, Luo S. The Regulatory Mechanism of Transthyretin Irreversible Aggregation through Liquid-to-Solid Phase Transition. Int J Mol Sci 2023; 24:ijms24043729. [PMID: 36835140 PMCID: PMC9960511 DOI: 10.3390/ijms24043729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/05/2023] [Accepted: 02/07/2023] [Indexed: 02/17/2023] Open
Abstract
Transthyretin (TTR) aggregation and amyloid formation are associated with several ATTR diseases, such as senile systemic amyloidosis (SSA) and familial amyloid polyneuropathy (FAP). However, the mechanism that triggers the initial pathologic aggregation process of TTR remains largely elusive. Lately, increasing evidence has suggested that many proteins associated with neurodegenerative diseases undergo liquid-liquid phase separation (LLPS) and subsequent liquid-to-solid phase transition before the formation of amyloid fibrils. Here, we demonstrate that electrostatic interactions mediate LLPS of TTR, followed by a liquid-solid phase transition, and eventually the formation of amyloid fibrils under a mildly acidic pH in vitro. Furthermore, pathogenic mutations (V30M, R34T, and K35T) of TTR and heparin promote the process of phase transition and facilitate the formation of fibrillar aggregates. In addition, S-cysteinylation, which is a kind of post-translational modification of TTR, reduces the kinetic stability of TTR and increases the propensity for aggregation, while another modification, S-sulfonation, stabilizes the TTR tetramer and reduces the aggregation rate. Once TTR was S-cysteinylated or S-sulfonated, they dramatically underwent the process of phase transition, providing a foundation for post-translational modifications that could modulate TTR LLPS in the context of pathological interactions. These novel findings reveal molecular insights into the mechanism of TTR from initial LLPS and subsequent liquid-to-solid phase transition to amyloid fibrils, providing a new dimension for ATTR therapy.
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4
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Del Tredici K, Braak H. Neuropathology and neuroanatomy of TDP-43 amyotrophic lateral sclerosis. Curr Opin Neurol 2022; 35:660-671. [PMID: 36069419 DOI: 10.1097/wco.0000000000001098] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
PURPOSE OF REVIEW Intracellular inclusions consisting of the abnormal TDP-43 protein and its nucleocytoplasmic mislocalization in selected cell types are hallmark pathological features of sALS. Descriptive (histological, morphological), anatomical, and molecular studies all have improved our understanding of the neuropathology of sporadic amyotrophic lateral sclerosis (sALS). This review highlights some of the latest developments in the field. RECENT FINDINGS Increasing evidence exists from experimental models for the prion-like nature of abnormal TDP-43, including a strain-effect, and with the help of neuroimaging-based studies, for spreading of disease along corticofugal connectivities in sALS. Progress has also been made with respect to finding and establishing reliable biomarkers (neurofilament levels, diffusor tensor imaging). SUMMARY The latest findings may help to elucidate the preclinical phase of sALS and to define possible mechanisms for delaying or halting disease development and progression.
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Affiliation(s)
- Kelly Del Tredici
- Clinical Neuroanatomy Section, Department of Neurology, Center for Biomedical Research, University of Ulm, Ulm, Germany
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5
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Stress induced TDP-43 mobility loss independent of stress granules. Nat Commun 2022; 13:5480. [PMID: 36123343 PMCID: PMC9485239 DOI: 10.1038/s41467-022-32939-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 08/24/2022] [Indexed: 11/25/2022] Open
Abstract
TAR DNA binding protein 43 (TDP-43) is closely related to the pathogenesis of amyotrophic lateral sclerosis (ALS) and translocates to stress granules (SGs). The role of SGs as aggregation-promoting “crucibles” for TDP-43, however, is still under debate. We analyzed TDP-43 mobility and localization under different stress and recovery conditions using live cell single-molecule tracking and super-resolution microscopy. Besides reduced mobility within SGs, a stress induced decrease of TDP-43 mobility in the cytoplasm and the nucleus was observed. Stress removal led to a recovery of TDP-43 mobility, which strongly depended on the stress duration. ‘Stimulated-emission depletion microscopy’ (STED) and ‘tracking and localization microscopy’ (TALM) revealed not only TDP-43 substructures within stress granules but also numerous patches of slow TDP-43 species throughout the cytoplasm. This work provides insights into the aggregation of TDP-43 in living cells and provide evidence suggesting that TDP-43 oligomerization and aggregation takes place in the cytoplasm separate from SGs. Amyotrophic Lateral Sclerosis related TDP-43 protein translocates to stress granules with a concomitant reduction in mobility. Here, the authors use single molecule tracking and find a stress-induced reduction in TDP-43 mobility also in the cytoplasm potentially relevant for TDP-43 aggregation.
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6
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Rhine K, Al-Azzam N, Yu T, Yeo GW. Aging RNA granule dynamics in neurodegeneration. Front Mol Biosci 2022; 9:991641. [PMID: 36188213 PMCID: PMC9523239 DOI: 10.3389/fmolb.2022.991641] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/22/2022] [Indexed: 12/30/2022] Open
Abstract
Disordered RNA-binding proteins and repetitive RNA sequences are the main genetic causes of several neurodegenerative diseases, including amyotrophic lateral sclerosis and Huntington's disease. Importantly, these components also seed the formation of cytoplasmic liquid-like granules, like stress granules and P bodies. Emerging evidence demonstrates that healthy granules formed via liquid-liquid phase separation can mature into solid- or gel-like inclusions that persist within the cell. These solidified inclusions are a precursor to the aggregates identified in patients, demonstrating that dysregulation of RNA granule biology is an important component of neurodegeneration. Here, we review recent literature highlighting how RNA molecules seed proteinaceous granules, the mechanisms of healthy turnover of RNA granules in cells, which biophysical properties underly a transition to solid- or gel-like material states, and why persistent granules disrupt the cellular homeostasis of neurons. We also identify various methods that will illuminate the contributions of disordered proteins and RNAs to neurodegeneration in ongoing research efforts.
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Affiliation(s)
- Kevin Rhine
- Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, CA, United States
- Stem Cell Program, University of California, San Diego, San Diego, CA, United States
- Institute for Genomic Medicine, University of California, San Diego, San Diego, CA, United States
| | - Norah Al-Azzam
- Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, CA, United States
- Stem Cell Program, University of California, San Diego, San Diego, CA, United States
- Institute for Genomic Medicine, University of California, San Diego, San Diego, CA, United States
- Neurosciences Graduate Program, University of California, San Diego, San Diego, CA, United States
| | - Tao Yu
- Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, CA, United States
- Stem Cell Program, University of California, San Diego, San Diego, CA, United States
- Institute for Genomic Medicine, University of California, San Diego, San Diego, CA, United States
| | - Gene W. Yeo
- Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, CA, United States
- Stem Cell Program, University of California, San Diego, San Diego, CA, United States
- Institute for Genomic Medicine, University of California, San Diego, San Diego, CA, United States
- Neurosciences Graduate Program, University of California, San Diego, San Diego, CA, United States
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7
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Cao MC, Scotter EL. Novel and known transcriptional targets of ALS/FTD protein TDP-43: Meta-analysis and interactive graphical database. Dis Model Mech 2022; 15:276263. [PMID: 35946434 PMCID: PMC9509890 DOI: 10.1242/dmm.049418] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 07/26/2022] [Indexed: 11/20/2022] Open
Abstract
TDP-43 proteinopathy is the major pathology in amyotrophic lateral sclerosis (ALS) and tau-negative frontotemporal dementia (FTD). Mounting evidence implicates loss of normal TDP-43 RNA processing function as a key pathomechanism. However, the RNA targets of TDP-43 differ by report, and have never been formally collated or compared between models and disease, hampering understanding of TDP-43 function. Here, we conducted re-analysis and meta-analysis of publicly available RNA-sequencing datasets from six TDP-43-knockdown models, and TDP-43-immunonegative neuronal nuclei from ALS/ FTD brain, to identify differentially expressed genes (DEGs) and exon usage (DEU) events. There was little overlap in DEGs between knockdown models, but PFKP, STMN2, CFP, KIAA1324 and TRHDE were common targets and were also differentially expressed in TDP-43-immunonegative neurons. DEG enrichment analysis revealed diverse biological pathways including immune and synaptic functions. Common DEU events in human datasets included well-known targets POLDIP3 and STMN2, and novel targets EXD3, MMAB, DLG5 and GOSR2. Our interactive database https://phpstack-449938-2576646.cloudwaysapps.com/ allows further exploration of TDP-43 DEG and DEU targets. Together, these data identify TDP-43 targets that can be exploited therapeutically or to validate loss-of-function processes.
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Affiliation(s)
- Maize C Cao
- School of Biological Sciences and Centre for Brain Research, University of Auckland, Auckland, New Zealand. 3A Symonds Street, Auckland 1010, New Zealand
| | - Emma L Scotter
- School of Biological Sciences and Centre for Brain Research, University of Auckland, Auckland, New Zealand. 3A Symonds Street, Auckland 1010, New Zealand
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8
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Paron F, Barattucci S, Cappelli S, Romano M, Berlingieri C, Stuani C, Laurents D, Mompeán M, Buratti E. Unravelling the toxic effects mediated by the neurodegenerative disease-associated S375G mutation of TDP-43 and its S375E phosphomimetic variant. J Biol Chem 2022; 298:102252. [PMID: 35835219 PMCID: PMC9364110 DOI: 10.1016/j.jbc.2022.102252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 06/23/2022] [Accepted: 06/25/2022] [Indexed: 12/05/2022] Open
Abstract
TAR DNA-binding protein 43 (TDP-43) is a nucleic acid–binding protein found in the nucleus that accumulates in the cytoplasm under pathological conditions, leading to proteinopathies, such as frontotemporal dementia and ALS. An emerging area of TDP-43 research is represented by the study of its post-translational modifications, the way they are connected to disease-associated mutations, and what this means for pathological processes. Recently, we described a novel mutation in TDP-43 in an early onset ALS case that was affecting a potential phosphorylation site in position 375 (S375G). A preliminary characterization showed that both the S375G mutation and its phosphomimetic variant, S375E, displayed altered nuclear–cytoplasmic distribution and cellular toxicity. To better investigate these effects, here we established cell lines expressing inducible WT, S375G, and S375E TDP-43 variants. Interestingly, we found that these mutants do not seem to affect well-studied aspects of TDP-43, such as RNA splicing or autoregulation, or protein conformation, dynamics, or aggregation, although they do display dysmorphic nuclear shape and cell cycle alterations. In addition, RNA-Seq analysis of these cell lines showed that although the disease-associated S375G mutation and its phosphomimetic S375E variant regulate distinct sets of genes, they have a common target in mitochondrial apoptotic genes. Taken together, our data strongly support the growing evidence that alterations in TDP-43 post-translational modifications can play a potentially important role in disease pathogenesis and provide a further link between TDP-43 pathology and mitochondrial health.
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Affiliation(s)
- Francesca Paron
- Molecular Pathology, International Centre for Genetic and Engineering Biotechnology (ICGEB), Trieste, Italy
| | - Simone Barattucci
- Molecular Pathology, International Centre for Genetic and Engineering Biotechnology (ICGEB), Trieste, Italy
| | - Sara Cappelli
- Molecular Pathology, International Centre for Genetic and Engineering Biotechnology (ICGEB), Trieste, Italy
| | - Maurizio Romano
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Christian Berlingieri
- Molecular Pathology, International Centre for Genetic and Engineering Biotechnology (ICGEB), Trieste, Italy
| | - Cristiana Stuani
- Molecular Pathology, International Centre for Genetic and Engineering Biotechnology (ICGEB), Trieste, Italy
| | - Douglas Laurents
- "Rocasolano" Institute for Physical Chemistry, Spanish National Research Council, Serrano 119, 28006, Madrid, Spain
| | - Miguel Mompeán
- "Rocasolano" Institute for Physical Chemistry, Spanish National Research Council, Serrano 119, 28006, Madrid, Spain
| | - Emanuele Buratti
- Molecular Pathology, International Centre for Genetic and Engineering Biotechnology (ICGEB), Trieste, Italy.
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9
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Johnson MA, Nuckols TA, Merino P, Bagchi P, Nandy S, Root J, Taylor G, Seyfried NT, Kukar T. Proximity-based labeling reveals DNA damage-induced phosphorylation of fused in sarcoma (FUS) causes distinct changes in the FUS protein interactome. J Biol Chem 2022; 298:102135. [PMID: 35709984 PMCID: PMC9372748 DOI: 10.1016/j.jbc.2022.102135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 05/13/2022] [Accepted: 05/14/2022] [Indexed: 01/18/2023] Open
Abstract
Accumulation of cytoplasmic inclusions containing fused in sarcoma (FUS), an RNA/DNA-binding protein, is a common hallmark of frontotemporal lobar degeneration and amyotrophic lateral sclerosis neuropathology. We have previously shown that DNA damage can trigger the cytoplasmic accumulation of N-terminally phosphorylated FUS. However, the functional consequences of N-terminal FUS phosphorylation are unknown. To gain insight into this question, we utilized proximity-dependent biotin labeling via ascorbate peroxidase 2 aired with mass spectrometry to investigate whether N-terminal phosphorylation alters the FUS protein-protein interaction network (interactome), and subsequently, FUS function. We report the first analysis comparing the interactomes of three FUS variants: homeostatic wildtype FUS (FUS WT), phosphomimetic FUS (FUS PM; a proxy for N-terminally phosphorylated FUS), and the toxic FUS proline 525 to leucine mutant (FUS P525L) that causes juvenile amyotrophic lateral sclerosis. We found that the phosphomimetic FUS interactome is uniquely enriched for a group of cytoplasmic proteins that mediate mRNA metabolism and translation, as well as nuclear proteins involved in the spliceosome and DNA repair functions. Furthermore, we identified and validated the RNA-induced silencing complex RNA helicase MOV10 as a novel interacting partner of FUS. Finally, we provide functional evidence that N-terminally phosphorylated FUS may disrupt homeostatic translation and steady-state levels of specific mRNA transcripts. Taken together, these results highlight phosphorylation as a unique modulator of the interactome and function of FUS.
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Affiliation(s)
- Michelle A. Johnson
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Thomas A. Nuckols
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Paola Merino
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Pritha Bagchi
- Emory Integrated Proteomics Core, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Srijita Nandy
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Jessica Root
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Georgia Taylor
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Nicholas T. Seyfried
- Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA,Emory Integrated Proteomics Core, Emory University, School of Medicine, Atlanta, Georgia, USA,Department of Neurology, Emory University, School of Medicine, Atlanta, Georgia, USA,Department of Biochemistry, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Thomas Kukar
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA,Department of Neurology, Emory University, School of Medicine, Atlanta, Georgia, USA,For correspondence: Thomas Kukar
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10
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Pushpalatha KV, Solyga M, Nakamura A, Besse F. RNP components condense into repressive RNP granules in the aging brain. Nat Commun 2022; 13:2782. [PMID: 35589695 PMCID: PMC9120078 DOI: 10.1038/s41467-022-30066-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 04/11/2022] [Indexed: 12/21/2022] Open
Abstract
Cytoplasmic RNP condensates enriched in mRNAs and proteins are found in various cell types and associated with both buffering and regulatory functions. While a clear link has been established between accumulation of aberrant RNP aggregates and progression of aging-related neurodegenerative diseases, the impact of physiological aging on neuronal RNP condensates has never been explored. Through high-resolution imaging, we uncover that RNP components progressively cluster into large yet dynamic granules in the aging Drosophila brain. We further show that age-dependent clustering is caused by an increase in the stoichiometry of the conserved helicase Me31B/DDX6, and requires PKA kinase activity. Finally, our functional analysis reveals that mRNA species recruited to RNP condensates upon aging exhibit age-dependent translational repression, indicating that co-clustering of selected mRNAs and translation regulators into repressive condensates may contribute to the specific post-transcriptional changes in gene expression observed in the course of aging. Aberrant RNA condensates are a hallmark of age-related neurodegenerative diseases. Here, the authors show that RNA condensation increases in aging Drosophila brains, triggering translation repression.
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Affiliation(s)
| | - Mathilde Solyga
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Akira Nakamura
- Department of Germline Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan.,Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Florence Besse
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France.
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11
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Bjork RT, Mortimore NP, Loganathan S, Zarnescu DC. Dysregulation of Translation in TDP-43 Proteinopathies: Deficits in the RNA Supply Chain and Local Protein Production. Front Neurosci 2022; 16:840357. [PMID: 35321094 PMCID: PMC8935057 DOI: 10.3389/fnins.2022.840357] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/09/2022] [Indexed: 12/19/2022] Open
Abstract
Local control of gene expression provides critical mechanisms for regulating development, maintenance and plasticity in the nervous system. Among the strategies known to govern gene expression locally, mRNA transport and translation have emerged as essential for a neuron’s ability to navigate developmental cues, and to establish, strengthen and remove synaptic connections throughout lifespan. Substantiating the role of RNA processing in the nervous system, several RNA binding proteins have been implicated in both developmental and age dependent neurodegenerative disorders. Of these, TDP-43 is an RNA binding protein that has emerged as a common denominator in amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD) and related disorders due to the identification of causative mutations altering its function and its accumulation in cytoplasmic aggregates observed in a significant fraction of ALS/FTD cases, regardless of etiology. TDP-43 is involved in multiple aspects of RNA processing including splicing, transport and translation. Given that one of the early events in disease pathogenesis is mislocalization from the nucleus to the cytoplasm, several studies have focused on elucidating the pathogenic role of TDP-43 in cytoplasmic translation. Here we review recent findings describing TDP-43 translational targets and potential mechanisms of translation dysregulation in TDP-43 proteinopathies across multiple experimental models including cultured cells, flies, mice and patient derived neurons.
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Affiliation(s)
- Reed T. Bjork
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States
- Neuroscience Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ, United States
| | - Nicholas P. Mortimore
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States
| | | | - Daniela C. Zarnescu
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States
- *Correspondence: Daniela C. Zarnescu,
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12
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High content screening and proteomic analysis identify a kinase inhibitor that rescues pathological phenotypes in a patient-derived model of Parkinson's disease. NPJ Parkinsons Dis 2022; 8:15. [PMID: 35149677 PMCID: PMC8837749 DOI: 10.1038/s41531-022-00278-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 01/12/2022] [Indexed: 11/30/2022] Open
Abstract
Combining high throughput screening approaches with induced pluripotent stem cell (iPSC)-based disease modeling represents a promising unbiased strategy to identify therapies for neurodegenerative disorders. Here we applied high content imaging on iPSC-derived neurons from patients with familial Parkinson’s disease bearing the G209A (p.A53T) α-synuclein (αSyn) mutation and launched a screening campaign on a small kinase inhibitor library. We thus identified the multi-kinase inhibitor BX795 that at a single dose effectively restores disease-associated neurodegenerative phenotypes. Proteomics profiling mapped the molecular pathways underlying the protective effects of BX795, comprising a cohort of 118 protein-mediators of the core biological processes of RNA metabolism, protein synthesis, modification and clearance, and stress response, all linked to the mTORC1 signaling hub. In agreement, expression of human p.A53T-αSyn in neuronal cells affected key components of the mTORC1 pathway resulting in aberrant protein synthesis that was restored in the presence of BX795 with concurrent facilitation of autophagy. Taken together, we have identified a promising small molecule with neuroprotective actions as candidate therapeutic for PD and other protein conformational disorders.
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13
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Valori CF, Neumann M. Contribution of RNA/DNA Binding Protein Dysfunction in Oligodendrocytes in the Pathogenesis of the Amyotrophic Lateral Sclerosis/Frontotemporal Lobar Degeneration Spectrum Diseases. Front Neurosci 2021; 15:724891. [PMID: 34539339 PMCID: PMC8440855 DOI: 10.3389/fnins.2021.724891] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 07/31/2021] [Indexed: 12/19/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) are two incurable neurodegenerative disorders, often considered as the extreme manifestations of a disease spectrum, as they share similar pathomechanisms. In support of this, pathological aggregation of the RNA/DNA binding proteins trans-activation response element DNA-binding protein 43 (TDP-43) or fused in sarcoma (FUS) is the pathological hallmark found in neurons and glial cells of subsets of patients affected by either condition (i.e., ALS/FTLD—TDP-43 or ALS/FTLD—FUS, respectively). Among glia, oligodendrocytes are the most abundant population, designated to ensheath the axons with myelin and to provide them with metabolic and trophic support. In this minireview, we recapitulate the neuropathological evidence for oligodendroglia impairment in ALS/FTLD. We then debate how TDP-43 and FUS target oligodendrocyte transcripts, thereby controlling their homeostatic abilities toward the axons. Finally, we discuss cellular and animal models aimed at investigating the functional consequences of manipulating TDP-43 and FUS in oligodendrocytes in vivo. Taken together, current data provide increasing evidence for an important role of TDP-43 and FUS-mediated oligodendroglia dysfunction in the pathogenesis of ALS/FTLD. Thus, targeting disrupted oligodendroglial functions may represent a new treatment approach for these conditions.
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Affiliation(s)
- Chiara F Valori
- Molecular Neuropathology of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases, Tübingen, Germany
| | - Manuela Neumann
- Molecular Neuropathology of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases, Tübingen, Germany.,Department of Neuropathology, University Hospital of Tübingen, Tübingen, Germany
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14
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Disease Mechanisms and Therapeutic Approaches in C9orf72 ALS-FTD. Biomedicines 2021; 9:biomedicines9060601. [PMID: 34070550 PMCID: PMC8229688 DOI: 10.3390/biomedicines9060601] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 01/15/2023] Open
Abstract
A hexanucleotide repeat expansion mutation in the first intron of C9orf72 is the most common known genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Since the discovery in 2011, numerous pathogenic mechanisms, including both loss and gain of function, have been proposed. The body of work overall suggests that toxic gain of function arising from bidirectionally transcribed repeat RNA is likely to be the primary driver of disease. In this review, we outline the key pathogenic mechanisms that have been proposed to date and discuss some of the novel therapeutic approaches currently in development.
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15
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Velázquez-Cruz A, Baños-Jaime B, Díaz-Quintana A, De la Rosa MA, Díaz-Moreno I. Post-translational Control of RNA-Binding Proteins and Disease-Related Dysregulation. Front Mol Biosci 2021; 8:658852. [PMID: 33987205 PMCID: PMC8111222 DOI: 10.3389/fmolb.2021.658852] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/22/2021] [Indexed: 12/20/2022] Open
Abstract
Cell signaling mechanisms modulate gene expression in response to internal and external stimuli. Cellular adaptation requires a precise and coordinated regulation of the transcription and translation processes. The post-transcriptional control of mRNA metabolism is mediated by the so-called RNA-binding proteins (RBPs), which assemble with specific transcripts forming messenger ribonucleoprotein particles of highly dynamic composition. RBPs constitute a class of trans-acting regulatory proteins with affinity for certain consensus elements present in mRNA molecules. However, these regulators are subjected to post-translational modifications (PTMs) that constantly adjust their activity to maintain cell homeostasis. PTMs can dramatically change the subcellular localization, the binding affinity for RNA and protein partners, and the turnover rate of RBPs. Moreover, the ability of many RBPs to undergo phase transition and/or their recruitment to previously formed membrane-less organelles, such as stress granules, is also regulated by specific PTMs. Interestingly, the dysregulation of PTMs in RBPs has been associated with the pathophysiology of many different diseases. Abnormal PTM patterns can lead to the distortion of the physiological role of RBPs due to mislocalization, loss or gain of function, and/or accelerated or disrupted degradation. This Mini Review offers a broad overview of the post-translational regulation of selected RBPs and the involvement of their dysregulation in neurodegenerative disorders, cancer and other pathologies.
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Affiliation(s)
- Alejandro Velázquez-Cruz
- Instituto de Investigaciones Químicas, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain
| | - Blanca Baños-Jaime
- Instituto de Investigaciones Químicas, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain
| | - Antonio Díaz-Quintana
- Instituto de Investigaciones Químicas, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain
| | - Miguel A De la Rosa
- Instituto de Investigaciones Químicas, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain
| | - Irene Díaz-Moreno
- Instituto de Investigaciones Químicas, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Seville, Spain
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16
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Krishnamurthy K, Pasinelli P. Synaptic dysfunction in amyotrophic lateral sclerosis/frontotemporal dementia: Therapeutic strategies and novel biomarkers. J Neurosci Res 2021; 99:1499-1503. [PMID: 33729613 DOI: 10.1002/jnr.24824] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/17/2021] [Accepted: 02/18/2021] [Indexed: 12/12/2022]
Affiliation(s)
- Karthik Krishnamurthy
- Department of Neuroscience, Jefferson Weinberg ALS Center, Vickie & Jack Farber Institute for Neuroscience, Jefferson University, Philadelphia, PA, USA
| | - Piera Pasinelli
- Department of Neuroscience, Jefferson Weinberg ALS Center, Vickie & Jack Farber Institute for Neuroscience, Jefferson University, Philadelphia, PA, USA
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17
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Low YH, Asi Y, Foti SC, Lashley T. Heterogeneous Nuclear Ribonucleoproteins: Implications in Neurological Diseases. Mol Neurobiol 2021; 58:631-646. [PMID: 33000450 PMCID: PMC7843550 DOI: 10.1007/s12035-020-02137-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/17/2020] [Indexed: 12/13/2022]
Abstract
Heterogenous nuclear ribonucleoproteins (hnRNPs) are a complex and functionally diverse family of RNA binding proteins with multifarious roles. They are involved, directly or indirectly, in alternative splicing, transcriptional and translational regulation, stress granule formation, cell cycle regulation, and axonal transport. It is unsurprising, given their heavy involvement in maintaining functional integrity of the cell, that their dysfunction has neurological implications. However, compared to their more established roles in cancer, the evidence of hnRNP implication in neurological diseases is still in its infancy. This review aims to consolidate the evidences for hnRNP involvement in neurological diseases, with a focus on spinal muscular atrophy (SMA), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), multiple sclerosis (MS), congenital myasthenic syndrome (CMS), and fragile X-associated tremor/ataxia syndrome (FXTAS). Understanding more about hnRNP involvement in neurological diseases can further elucidate the pathomechanisms involved in these diseases and perhaps guide future therapeutic advances.
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Affiliation(s)
- Yi-Hua Low
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Disorders, UCL Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
- Duke-NUS Medical School, Singapore, Singapore
| | - Yasmine Asi
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Disorders, UCL Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Sandrine C Foti
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Disorders, UCL Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Tammaryn Lashley
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Disorders, UCL Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK.
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK.
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18
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Johnson MA, Deng Q, Taylor G, McEachin ZT, Chan AWS, Root J, Bassell GJ, Kukar T. Divergent FUS phosphorylation in primate and mouse cells following double-strand DNA damage. Neurobiol Dis 2020; 146:105085. [PMID: 32950644 PMCID: PMC8064403 DOI: 10.1016/j.nbd.2020.105085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 09/10/2020] [Accepted: 09/15/2020] [Indexed: 12/15/2022] Open
Abstract
Fused in sarcoma (FUS) is a RNA/DNA protein involved in multiple nuclear and cytoplasmic functions including transcription, splicing, mRNA trafficking, and stress granule formation. To accomplish these many functions, FUS must shuttle between cellular compartments in a highly regulated manner. When shuttling is disrupted, FUS abnormally accumulates into cytoplasmic inclusions that can be toxic. Disrupted shuttling of FUS into the nucleus is a hallmark of ~10% of frontotemporal lobar degeneration (FTLD) cases, the neuropathology that underlies frontotemporal dementia (FTD). Multiple pathways are known to disrupt nuclear/cytoplasmic shuttling of FUS. In earlier work, we discovered that double-strand DNA breaks (DSBs) trigger DNA-dependent protein kinase (DNA-PK) to phosphorylate FUS (p-FUS) at N-terminal residues leading to the cytoplasmic accumulation of FUS. Therefore, DNA damage may contribute to the development of FTLD pathology with FUS inclusions. In the present study, we examined how DSBs effect FUS phosphorylation in various primate and mouse cellular models. All cell lines derived from human and non-human primates exhibit N-terminal FUS phosphorylation following calicheamicin γ1 (CLM) induced DSBs. In contrast, we were unable to detect FUS phosphorylation in mouse-derived primary neurons or immortalized cell lines regardless of CLM treatment, duration, or concentration. Despite DNA damage induced by CLM treatment, we find that mouse cells do not phosphorylate FUS, likely due to reduced levels and activity of DNA-PK compared to human cells. Taken together, our work reveals that mouse-derived cellular models regulate FUS in an anomalous manner compared to primate cells. This raises the possibility that mouse models may not fully recapitulate the pathogenic cascades that lead to FTLD with FUS pathology.
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Affiliation(s)
- Michelle A Johnson
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Qiudong Deng
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Georgia Taylor
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Zachary T McEachin
- Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America; Department of Cell Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Laboratory of Translational Cell Biology, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Anthony W S Chan
- Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America; Department of Human Genetics, Emory University, School of Medicine, Atlanta, GA, United States of America; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, 954 Gatewood Rd, NE, Atlanta, GA, United States of America
| | - Jessica Root
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Gary J Bassell
- Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America; Department of Cell Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Laboratory of Translational Cell Biology, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Thomas Kukar
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America; Department of Neurology, Emory University, School of Medicine, Atlanta, GA, United States of America.
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19
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Solomon DA, Mitchell JC, Salcher-Konrad MT, Vance CA, Mizielinska S. Review: Modelling the pathology and behaviour of frontotemporal dementia. Neuropathol Appl Neurobiol 2020; 45:58-80. [PMID: 30582188 DOI: 10.1111/nan.12536] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/16/2018] [Indexed: 12/11/2022]
Abstract
Frontotemporal dementia (FTD) encompasses a collection of clinically and pathologically diverse neurological disorders. Clinical features of behavioural and language dysfunction are associated with neurodegeneration, predominantly of frontal and temporal cortices. Over the past decade, there have been significant advances in the understanding of the genetic aetiology and neuropathology of FTD which have led to the creation of various disease models to investigate the molecular pathways that contribute to disease pathogenesis. The generation of in vivo models of FTD involves either targeting genes with known disease-causative mutations such as GRN and C9orf72 or genes encoding proteins that form the inclusions that characterize the disease pathologically, such as TDP-43 and FUS. This review provides a comprehensive summary of the different in vivo model systems used to understand pathomechanisms in FTD, with a focus on disease models which reproduce aspects of the wide-ranging behavioural phenotypes seen in people with FTD. We discuss the emerging disease pathways that have emerged from these in vivo models and how this has shaped our understanding of disease mechanisms underpinning FTD. We also discuss the challenges of modelling the complex clinical symptoms shown by people with FTD, the confounding overlap with features of motor neuron disease, and the drive to make models more disease-relevant. In summary, in vivo models can replicate many pathological and behavioural aspects of clinical FTD, but robust and thorough investigations utilizing shared features and variability between disease models will improve the disease-relevance of findings and thus better inform therapeutic development.
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Affiliation(s)
- D A Solomon
- UK Dementia Research Institute, King's College London, London, Camberwell, UK.,Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - J C Mitchell
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - M-T Salcher-Konrad
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - C A Vance
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - S Mizielinska
- UK Dementia Research Institute, King's College London, London, Camberwell, UK.,Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
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20
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Neumann M, Mackenzie IRA. Review: Neuropathology of non-tau frontotemporal lobar degeneration. Neuropathol Appl Neurobiol 2020; 45:19-40. [PMID: 30357887 DOI: 10.1111/nan.12526] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 09/29/2018] [Indexed: 12/12/2022]
Abstract
Frontotemporal dementia (FTD) is a heterogeneous clinical syndrome associated with frontotemporal lobar degeneration (FTLD) as a relatively consistent neuropathological hallmark feature. However, the discoveries in the past decade of many of the relevant pathological proteins aggregating in human FTD brains in addition to several new FTD causing gene mutations underlined that FTD is a diverse condition on the neuropathological and genetic basis. This resulted in a novel molecular classification of these conditions based on the predominant protein abnormality and allows most cases of FTD to be placed now into one of three broad molecular subgroups; FTLD with tau, TAR DNA-binding protein 43 or FET protein accumulation (FTLD-tau, FTLD-TDP and FTLD-FET respectively). This review will provide an overview of the molecular neuropathology of non-tau FTLD, insights into disease mechanisms gained from the study of human post mortem tissue as well as discussion of current controversies in the field.
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Affiliation(s)
- M Neumann
- Department of Neuropathology, University Hospital of Tübingen, Tübingen, Germany.,Molecular Neuropathology of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - I R A Mackenzie
- Department of Pathology, University of British Columbia and Vancouver General Hospital, Vancouver, BC, Canada
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21
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Collins M, Li Y, Bowser R. RBM45 associates with nuclear stress bodies and forms nuclear inclusions during chronic cellular stress and in neurodegenerative diseases. Acta Neuropathol Commun 2020; 8:91. [PMID: 32586379 PMCID: PMC7318465 DOI: 10.1186/s40478-020-00965-y] [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: 06/11/2020] [Accepted: 06/11/2020] [Indexed: 12/12/2022] Open
Abstract
The RNA binding protein (RBP) RBM45 forms nuclear and cytoplasmic inclusions in neurons and glia in amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration with TDP-43 proteinopathy (FTLD-TDP), and Alzheimer's disease (AD). The normal functions of RBM45 are poorly understood, as are the mechanisms by which it forms inclusions in disease. To better understand the normal and pathological functions of RBM45, we evaluated whether the protein functions via association with several membraneless organelles and whether such an association could promote the formation of nuclear RBM45 inclusions. Under basal conditions, RBM45 is diffusely distributed throughout the nucleus and does not localize to membraneless organelles, including nuclear speckles, Cajal bodies, or nuclear gems. During cellular stress, however, nuclear RBM45 undergoes a reversible, RNA-binding dependent incorporation into nuclear stress bodies (NSBs). Chronic stress leads to the persistent association of RBM45 with NSBs and the irreversible accumulation of nuclear RBM45 inclusions. We also quantified the cell type- and disease-specific patterns of RBM45 pathology in ALS, FTLD-TDP, and AD. RBM45 nuclear and cytoplasmic inclusions are found in both neurons and glia in ALS, FTLD-TDP, and AD but are absent in non-neurologic disease controls. Across neurodegenerative diseases, RBM45 nuclear inclusion pathology occurs more frequently than cytoplasmic RBM45 inclusion pathology and exhibits cell type-specific variation. Collectively, our results define new stress-associated functions of RBM45, a mechanism for nuclear RBM45 inclusion formation, a role for NSBs in the pathogenesis of ALS, FTLD-TDP, and AD, and further underscore the importance of protein self-association to both the normal and pathological functions of RBPs in these diseases.
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22
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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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23
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Hock EM, Maniecka Z, Hruska-Plochan M, Reber S, Laferrière F, Sahadevan M K S, Ederle H, Gittings L, Pelkmans L, Dupuis L, Lashley T, Ruepp MD, Dormann D, Polymenidou M. Hypertonic Stress Causes Cytoplasmic Translocation of Neuronal, but Not Astrocytic, FUS due to Impaired Transportin Function. Cell Rep 2020; 24:987-1000.e7. [PMID: 30044993 DOI: 10.1016/j.celrep.2018.06.094] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 05/14/2018] [Accepted: 06/22/2018] [Indexed: 12/20/2022] Open
Abstract
The primarily nuclear RNA-binding protein FUS (fused in sarcoma) forms pathological cytoplasmic inclusions in a subset of early-onset amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) patients. In response to cellular stress, FUS is recruited to cytoplasmic stress granules, which are hypothesized to act as precursors of pathological inclusions. We monitored the stress-induced nucleocytoplasmic shuttling of endogenous FUS in an ex vivo mouse CNS model and human neural networks. We found that hyperosmolar, but not oxidative, stress induced robust cytoplasmic translocation of neuronal FUS, with transient nuclear clearance and loss of function. Surprisingly, this reaction is independent of stress granule formation and the molecular pathways activated by hyperosmolarity. Instead, it represents a mechanism mediated by cytoplasmic redistribution of Transportin 1/2 and is potentiated by transcriptional inhibition. Importantly, astrocytes, which remain unaffected in ALS/FTD-FUS, are spared from this stress reaction that may signify the initial event in the development of FUS pathology.
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Affiliation(s)
- Eva-Maria Hock
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Life Science Zurich Graduate School, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Zuzanna Maniecka
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Life Science Zurich Graduate School, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Marian Hruska-Plochan
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Stefan Reber
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Florent Laferrière
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Sonu Sahadevan M K
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Life Science Zurich Graduate School, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Helena Ederle
- BioMedical Center (BMC), Ludwig-Maximiians-University Munich, 82152 Planegg-Martinsried, Germany; Graduate School of Systemic Neurosciences (GSN), 82152 Planegg-Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Lauren Gittings
- Queen Square Brain Bank for Neurological Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 1PJ, UK
| | - Lucas Pelkmans
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Luc Dupuis
- Faculty of Medicine, INSERM UMR-S1118 and Fédération de Médecine Translationnelle, Université de Strasbourg, Strasbourg, France
| | - Tammaryn Lashley
- Queen Square Brain Bank for Neurological Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 1PJ, UK
| | - Marc-David Ruepp
- UK Dementia Research Institute Centre at King's College London, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, 125 Coldharbour Lane, London SE5 9NU, UK
| | - Dorothee Dormann
- BioMedical Center (BMC), Ludwig-Maximiians-University Munich, 82152 Planegg-Martinsried, Germany; Graduate School of Systemic Neurosciences (GSN), 82152 Planegg-Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Magdalini Polymenidou
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Life Science Zurich Graduate School, University of Zurich and ETH Zurich, Zurich, Switzerland.
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24
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Pushpalatha KV, Besse F. Local Translation in Axons: When Membraneless RNP Granules Meet Membrane-Bound Organelles. Front Mol Biosci 2019; 6:129. [PMID: 31824961 PMCID: PMC6882739 DOI: 10.3389/fmolb.2019.00129] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/06/2019] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic cell compartmentalization relies on long-known membrane-delimited organelles, as well as on more recently discovered membraneless macromolecular condensates. How these two types of organelles interact to regulate cellular functions is still largely unclear. In this review, we highlight how membraneless ribonucleoprotein (RNP) organelles, enriched in RNAs and associated regulatory proteins, cooperate with membrane-bound organelles for tight spatio-temporal control of gene expression in the axons of neuronal cells. Specifically, we present recent evidence that motile membrane-bound organelles are used as vehicles by RNP cargoes, promoting the long-range transport of mRNA molecules to distal axons. As demonstrated by recent work, membrane-bound organelles also promote local protein synthesis, by serving as platforms for the local translation of mRNAs recruited to their outer surface. Furthermore, dynamic and specific association between RNP cargoes and membrane-bound organelles is mediated by bi-partite adapter molecules that interact with both types of organelles selectively, in a regulated-manner. Maintaining such a dynamic interplay is critical, as alterations in this process are linked to neurodegenerative diseases. Together, emerging studies thus point to the coordination of membrane-bound and membraneless organelles as an organizing principle underlying local cellular responses.
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Affiliation(s)
| | - Florence Besse
- Université Côte d'Azur, CNRS, Inserm, Institut de Biology Valrose, Nice, France
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25
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Fernandopulle M, Wang G, Nixon-Abell J, Qamar S, Balaji V, Morihara R, St George-Hyslop PH. Inherited and Sporadic Amyotrophic Lateral Sclerosis and Fronto-Temporal Lobar Degenerations arising from Pathological Condensates of Phase Separating Proteins. Hum Mol Genet 2019; 28:R187-R196. [PMID: 31595953 PMCID: PMC6872449 DOI: 10.1093/hmg/ddz162] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 12/11/2022] Open
Abstract
Recent work on the biophysics of proteins with low complexity, intrinsically disordered domains that have the capacity to form biological condensates has profoundly altered the concepts about the pathogenesis of inherited and sporadic neurodegenerative disorders associated with pathological accumulation of these proteins. In the present review, we use the FUS, TDP-43 and A11 proteins as examples to illustrate how missense mutations and aberrant post-translational modifications of these proteins cause amyotrophic lateral sclerosis (ALS) and fronto-temporal lobar degeneration (FTLD).
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Affiliation(s)
- Michael Fernandopulle
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK, CB2 0XY
| | - GuoZhen Wang
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK, CB2 0XY
| | - Jonathon Nixon-Abell
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK, CB2 0XY
| | - Seema Qamar
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK, CB2 0XY
| | - Varun Balaji
- Tanz Centre for Research in Neurodegenerative Diseases, and Departments of Medicine, University of Toronto, Toronto, Ontario, Canada, M5S 3H2
| | - Ryuta Morihara
- Tanz Centre for Research in Neurodegenerative Diseases, and Departments of Medicine, University of Toronto, Toronto, Ontario, Canada, M5S 3H2
| | - Peter H St George-Hyslop
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK, CB2 0XY
- Tanz Centre for Research in Neurodegenerative Diseases, and Departments of Medicine, University of Toronto, Toronto, Ontario, Canada, M5S 3H2
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26
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Zhang C, Rabouille C. Membrane-Bound Meet Membraneless in Health and Disease. Cells 2019; 8:cells8091000. [PMID: 31470564 PMCID: PMC6770257 DOI: 10.3390/cells8091000] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/26/2019] [Accepted: 08/27/2019] [Indexed: 12/12/2022] Open
Abstract
Membraneless organelles (MLOs) are defined as cellular structures that are not sealed by a lipidic membrane and are shown to form by phase separation. They exist in both the nucleus and the cytoplasm that is also heavily populated by numerous membrane-bound organelles. Even though the name membraneless suggests that MLOs are free of membrane, both membrane and factors regulating membrane trafficking steps are emerging as important components of MLO formation and function. As a result, we name them biocondensates. In this review, we examine the relationships between biocondensates and membrane. First, inhibition of membrane trafficking in the early secretory pathway leads to the formation of biocondensates (P-bodies and Sec bodies). In the same vein, stress granules have a complex relationship with the cyto-nuclear transport machinery. Second, membrane contributes to the regulated formation of phase separation in the cells and we will present examples including clustering at the plasma membrane and at the synapse. Finally, the whole cell appears to transit from an interphase phase-separated state to a mitotic diffuse state in a DYRK3 dependent manner. This firmly establishes a crosstalk between the two types of cell organization that will need to be further explored.
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Affiliation(s)
- Chujun Zhang
- Hubrecht Institute of the Royal Netherlands Academy of Arts and Sciences, and University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands
| | - Catherine Rabouille
- Hubrecht Institute of the Royal Netherlands Academy of Arts and Sciences, and University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands.
- Department of Biomedical Science of Cells and Systems, University Medical Center Groningen, 9713 AV Groningen, The Netherlands.
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27
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Abstract
The discovery that repeat expansions in the C9orf72 gene are a frequent cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) has revolutionized our understanding of these diseases. Substantial headway has been made in characterizing C9orf72-mediated disease and unravelling its underlying aetiopathogenesis. Three main disease mechanisms have been proposed: loss of function of the C9orf72 protein and toxic gain of function from C9orf72 repeat RNA or from dipeptide repeat proteins produced by repeat-associated non-ATG translation. Several downstream processes across a range of cellular functions have also been implicated. In this article, we review the pathological and mechanistic features of C9orf72-associated FTD and ALS (collectively termed C9FTD/ALS), the model systems used to study these conditions, and the probable initiators of downstream disease mechanisms. We suggest that a combination of upstream mechanisms involving both loss and gain of function and downstream cellular pathways involving both cell-autonomous and non-cell-autonomous effects contributes to disease progression.
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Affiliation(s)
- Rubika Balendra
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK.,Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, UCL, London, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK. .,UK Dementia Research Institute at UCL, UCL Institute of Neurology, London, UK.
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28
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Stackpole EE, Akins MR, Ivshina M, Murthy AC, Fawzi NL, Fallon JR. EGFP insertional mutagenesis reveals multiple FXR2P fibrillar states with differing ribosome association in neurons. Biol Open 2019; 8:8/8/bio046383. [PMID: 31434643 PMCID: PMC6737979 DOI: 10.1242/bio.046383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
RNA-binding proteins (RBPs) function in higher-order assemblages such as RNA granules to regulate RNA localization and translation. The Fragile X homolog FXR2P is an RBP essential for formation of neuronal Fragile X granules that associate with axonal mRNA and ribosomes in the intact brain. However, the FXR2P domains important for assemblage formation in a cellular system are unknown. Here we used an EGFP insertional mutagenesis approach to probe for FXR2P intrinsic features that influence its structural states. We tested 18 different in-frame FXR2PEGFP fusions in neurons and found that the majority did not impact assemblage formation. However, EGFP insertion within a 23 amino acid region of the low complexity (LC) domain induced FXR2PEGFP assembly into two distinct fibril states that were observed in isolation or in highly-ordered bundles. FXR2PEGFP fibrils exhibited different developmental timelines, ultrastructures and ribosome associations. Formation of both fibril types was dependent on an intact RNA-binding domain. These results suggest that restricted regions of the LC domain, together with the RNA-binding domain, may be important for FXR2P structural state organization in neurons. Summary: A mutagenesis study reveals that the higher-order structural states of the RBP FXR2P in neurons can be regulated by manipulation of the LC and RNA-binding domains.
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Affiliation(s)
- Emily E Stackpole
- Department of Neuroscience, Brown University, Providence, RI 02912, USA
| | - Michael R Akins
- Department of Biology, Drexel University, Philadelphia, PA 19104, USA
| | - Maria Ivshina
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Anastasia C Murthy
- Graduate Program in Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, USA.,Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI 02912, USA
| | - Nicolas L Fawzi
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI 02912, USA
| | - Justin R Fallon
- Department of Neuroscience, Brown University, Providence, RI 02912, USA
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29
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Formicola N, Vijayakumar J, Besse F. Neuronal ribonucleoprotein granules: Dynamic sensors of localized signals. Traffic 2019; 20:639-649. [PMID: 31206920 DOI: 10.1111/tra.12672] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/03/2019] [Accepted: 06/11/2019] [Indexed: 12/14/2022]
Abstract
Membrane-less organelles, because of their capacity to dynamically, selectively and reversibly concentrate molecules, are very well adapted for local information processing and rapid response to environmental fluctuations. These features are particularly important in the context of neuronal cells, where synapse-specific activation, or localized extracellular cues, induce signaling events restricted to specialized axonal or dendritic subcompartments. Neuronal ribonucleoprotein (RNP) particles, or granules, are nonmembrane bound macromolecular condensates that concentrate specific sets of mRNAs and regulatory proteins, promoting their long-distance transport to axons or dendrites. Neuronal RNP granules also have a dual function in regulating the translation of associated mRNAs: while preventing mRNA translation at rest, they fuel local protein synthesis upon activation. As revealed by recent work, rapid and reversible switches between these two functional modes are triggered by modifications of the networks of interactions underlying RNP granule assembly. Such flexible properties also come with a cost, as neuronal RNP granules are prone to transition into pathological aggregates in response to mutations, aging, or cellular stresses, further emphasizing the need to better understand the mechanistic principles governing their dynamic assembly and regulation in living systems.
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30
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Piatnitskaia S, Takahashi M, Kitaura H, Katsuragi Y, Kakihana T, Zhang L, Kakita A, Iwakura Y, Nawa H, Miura T, Ikeuchi T, Hara T, Fujii M. USP10 is a critical factor for Tau-positive stress granule formation in neuronal cells. Sci Rep 2019; 9:10591. [PMID: 31332267 PMCID: PMC6646309 DOI: 10.1038/s41598-019-47033-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 07/08/2019] [Indexed: 12/31/2022] Open
Abstract
Tau aggregates in neurons of brain lesions is a hallmark pathology of tauopathies, including Alzheimer’s disease (AD). Recent studies suggest that the RNA-binding protein TIA1 initiates Tau aggregation by inducing the formation of stress granules (SGs) containing Tau. SGs are stress-inducible cytoplasmic protein aggregates containing many RNA-binding proteins that has been implicated as an initial site of multiple pathogenic protein aggregates in several neurodegenerative diseases. In this study, we found that ubiquitin-specific protease 10 (USP10) is a critical factor for the formation of Tau/TIA1/USP10-positive SGs. Proteasome inhibition or TIA1-overexpression in HT22 neuronal cells induced the formation of TIA1/Tau-positive SGs, and the formations were severely attenuated by depletion of USP10. In addition, the overexpression of USP10 without stress stimuli in HT22 cells induced TIA1/Tau/USP10-positive SGs in a deubiquitinase-independent manner. In AD brain lesions, USP10 was colocalized with Tau aggregates in the cell body of neurons. The present findings suggest that USP10 plays a key role in the initiation of pathogenic Tau aggregation in AD through SG formation.
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Affiliation(s)
- Svetlana Piatnitskaia
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, 951-8510, Japan
| | - Masahiko Takahashi
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, 951-8510, Japan
| | - Hiroki Kitaura
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Yoshinori Katsuragi
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, 951-8510, Japan
| | - Taichi Kakihana
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, 951-8510, Japan
| | - Lu Zhang
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Yuriko Iwakura
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Hiroyuki Nawa
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Takeshi Miura
- Department of Molecular Genetics, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Takeshi Ikeuchi
- Department of Molecular Genetics, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Toshifumi Hara
- Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, Nagoya, Japan
| | - Masahiro Fujii
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, 951-8510, Japan.
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31
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Ferrari R, Manzoni C, Hardy J. Genetics and molecular mechanisms of frontotemporal lobar degeneration: an update and future avenues. Neurobiol Aging 2019; 78:98-110. [PMID: 30925302 DOI: 10.1016/j.neurobiolaging.2019.02.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 01/21/2019] [Accepted: 02/06/2019] [Indexed: 12/11/2022]
Abstract
Frontotemporal lobar degeneration (FTLD) is the second most common form of dementia after Alzheimer's disease. The study and the dissection of FTLD is complex due to its clinical, pathological, and genetic heterogeneity. In this review, we survey the state-of-the-art genetics of familial FTLD and recapitulate our current understanding of the genetic architecture of sporadic FTLD by summarizing results of genome-wide association studies performed in FTLD to date. We then discuss the challenges of translating these heterogeneous genetic features into the understanding of the molecular underpinnings of FTLD pathogenesis. We particularly highlight a number of susceptibility processes that appear to be conserved across familial and sporadic cases (e.g., and the cellular waste disposal pathways, and immune system signaling) and finally describe cutting-edge approaches, based on mathematical prediction tools, highlighting novel intriguing risk pathways such as DNA damage response as an emerging theme in FTLD.
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Affiliation(s)
- Raffaele Ferrari
- Department of Neurodegenerative Disease, University College London, Institute of Neurology, London, UK.
| | - Claudia Manzoni
- Department of Neurodegenerative Disease, University College London, Institute of Neurology, London, UK; School of Pharmacy, University of Reading, Reading, UK
| | - John Hardy
- Department of Neurodegenerative Disease, University College London, Institute of Neurology, London, UK
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32
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Borroni B, Alberici A, Buratti E. Review: Molecular pathology of frontotemporal lobar degenerations. Neuropathol Appl Neurobiol 2019; 45:41-57. [DOI: 10.1111/nan.12534] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 12/04/2018] [Indexed: 02/07/2023]
Affiliation(s)
- B. Borroni
- Neurology Clinic; Department of Clinical and Experimental Sciences; University of Brescia; Brescia Italy
| | - A. Alberici
- Neurology Clinic; Department of Clinical and Experimental Sciences; University of Brescia; Brescia Italy
| | - E. Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB); Trieste Italy
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33
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Newell K, Paron F, Mompean M, Murrell J, Salis E, Stuani C, Pattee G, Romano M, Laurents D, Ghetti B, Buratti E. Dysregulation of TDP-43 intracellular localization and early onset ALS are associated with a TARDBP S375G variant. Brain Pathol 2018; 29:397-413. [PMID: 30461104 PMCID: PMC6875182 DOI: 10.1111/bpa.12680] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 11/12/2018] [Indexed: 02/06/2023] Open
Abstract
We investigated the Central Nervous System (CNS) and skeletal muscle tissue from A woman was clinically diagnosed with amyotrophic lateral sclerosis (ALS) at the age of 22. Neuropathologic evaluation showed upper and lower motor neuron loss, corticospinal tract degeneration and skeletal muscle denervation. Analysis of the patient's Deoxyribonucleic acid (DNA) revealed a AGT>GGT change resulting in an S375G substitution in the C-terminal region of TDP-43. This variant was previously reported as being benign. Considering the early onset and severity of the disease in this patient, we tested the effects of this genetic variant on TDP-43 localization, pre-mRNA splicing activity and toxicity, in parallel with the effects on known neighboring disease-associated mutations. In cell lines, expressed in culture, S375G TDP-43 appeared to be more significantly localized in the nucleus and to exert higher toxicity than wild-type TDP-43. Strikingly, a phosphomimic mutant at the same residue (S375E) showed a strong tendency to accumulate in the cytoplasm, especially under stress conditions, and molecular dynamics simulations suggest that phosphorylation of this residue can disrupt TDP-43 intermolecular interactions. The results of the current study highlight the importance of phosphorylation and regulation of TDP-43 nuclear-cytoplasmic shuttling/redistribution, in relation to the pathogenetic mechanisms involved in different forms of ALS.
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Affiliation(s)
- Kathy Newell
- University of Kansas School of Medicine, Pathology & Laboratory Medicine, Kansas City, MO
| | - Francesca Paron
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Miguel Mompean
- University of Castile-La Mancha, Instituto Regional de Investigación Científica Aplicada (IRICA), Ciudad Real, Spain
| | - Jill Murrell
- Indiana University School of Medicine, Pathology & Laboratory Medicine, Indianapolis, IN
| | - Elisa Salis
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Cristiana Stuani
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Gary Pattee
- University of Nebraska Medical Center, Lincoln, NE
| | - Maurizio Romano
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Douglas Laurents
- Instituto de Química Física "Rocasolano", Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Bernardino Ghetti
- Indiana University School of Medicine, Pathology & Laboratory Medicine, Indianapolis, IN
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
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34
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Nötzel M, Rosso G, Möllmert S, Seifert A, Schlüßler R, Kim K, Hermann A, Guck J. Axonal Transport, Phase-Separated Compartments, and Neuron Mechanics - A New Approach to Investigate Neurodegenerative Diseases. Front Cell Neurosci 2018; 12:358. [PMID: 30356682 PMCID: PMC6189317 DOI: 10.3389/fncel.2018.00358] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 09/24/2018] [Indexed: 01/07/2023] Open
Abstract
Many molecular and cellular pathogenic mechanisms of neurodegenerative diseases have been revealed. However, it is unclear what role a putatively impaired neuronal transport with respect to altered mechanical properties of neurons play in the initiation and progression of such diseases. The biochemical aspects of intracellular axonal transport, which is important for molecular movements through the cytoplasm, e.g., mitochondrial movement, has already been studied. Interestingly, transport deficiencies are associated with the emergence of the affliction and potentially linked to disease transmission. Transport along the axon depends on the normal function of the neuronal cytoskeleton, which is also a major contributor to neuronal mechanical properties. By contrast, little attention has been paid to the mechanical properties of neurons and axons impaired by neurodegeneration, and of membraneless, phase-separated organelles such as stress granules (SGs) within neurons. Mechanical changes may indicate cytoskeleton reorganization and function, and thus give information about the transport and other system impairment. Nowadays, several techniques to investigate cellular mechanical properties are available. In this review, we discuss how select biophysical methods to probe material properties could contribute to the general understanding of mechanisms underlying neurodegenerative diseases.
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Affiliation(s)
- Martin Nötzel
- Biotechnology Center, Dresden University of Technology, Dresden, Germany
| | - Gonzalo Rosso
- Biotechnology Center, Dresden University of Technology, Dresden, Germany
| | - Stephanie Möllmert
- Biotechnology Center, Dresden University of Technology, Dresden, Germany
| | - Anne Seifert
- Department of Neurology, Technische Universität Dresden, Dresden, Germany
- Center for Regenerative Therapies (CRTD), Technische Universität Dresden, Dresden, Germany
- German Center for Neurodegenerative Diseases, Dresden, Germany
| | - Raimund Schlüßler
- Biotechnology Center, Dresden University of Technology, Dresden, Germany
| | - Kyoohyun Kim
- Biotechnology Center, Dresden University of Technology, Dresden, Germany
| | - Andreas Hermann
- Department of Neurology, Technische Universität Dresden, Dresden, Germany
- Center for Regenerative Therapies (CRTD), Technische Universität Dresden, Dresden, Germany
- German Center for Neurodegenerative Diseases, Dresden, Germany
| | - Jochen Guck
- Biotechnology Center, Dresden University of Technology, Dresden, Germany
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35
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Kato M, McKnight SL. A Solid-State Conceptualization of Information Transfer from Gene to Message to Protein. Annu Rev Biochem 2018; 87:351-390. [DOI: 10.1146/annurev-biochem-061516-044700] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this review, we describe speculative ideas and early stage research concerning the flow of genetic information from the nuclear residence of genes to the disparate, cytoplasmic sites of protein synthesis. We propose that this process of information transfer is meticulously guided by transient structures formed from protein segments of low sequence complexity/intrinsic disorder. These low complexity domains are ubiquitously associated with regulatory proteins that control gene expression and RNA biogenesis, but they are also found in the central channel of nuclear pores, the nexus points of intermediate filament assembly, and the locations of action of other well-studied cellular proteins and pathways. Upon being organized into localized cellular positions via mechanisms utilizing properly folded protein domains, thereby facilitating elevated local concentration, certain low complexity domains adopt cross-β interactions that are both structurally specific and labile to disassembly. These weakly tethered assemblies, we propose, are built to relay the passage of genetic information from one site to another within a cell, ensuring that the process is of extreme fidelity.
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Affiliation(s)
- Masato Kato
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9152, USA
| | - Steven L. McKnight
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9152, USA
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36
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Ederle H, Funk C, Abou-Ajram C, Hutten S, Funk EBE, Kehlenbach RH, Bailer SM, Dormann D. Nuclear egress of TDP-43 and FUS occurs independently of Exportin-1/CRM1. Sci Rep 2018; 8:7084. [PMID: 29728564 PMCID: PMC5935713 DOI: 10.1038/s41598-018-25007-5] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 04/13/2018] [Indexed: 12/11/2022] Open
Abstract
TDP-43 and FUS are nuclear proteins with multiple functions in mRNA processing. They play key roles in ALS (amyotrophic lateral sclerosis) and FTD (frontotemporal dementia), where they are partially lost from the nucleus and aggregate in the cytoplasm of neurons and glial cells. Defects in nucleocytoplasmic transport contribute to this pathology, hence nuclear import of both proteins has been studied in detail. However, their nuclear export routes remain poorly characterized and it is unclear whether aberrant nuclear export contributes to TDP-43 or FUS pathology. Here we show that predicted nuclear export signals in TDP-43 and FUS are non-functional and that both proteins are exported independently of the export receptor CRM1/Exportin-1. Silencing of Exportin-5 or the mRNA export factor Aly/REF, as well as mutations that abrogate RNA-binding do not impair export of TDP-43 and FUS. However, artificially enlarging TDP-43 or FUS impairs their nuclear egress, suggesting that they could leave the nucleus by passive diffusion. Finally, we found that inhibition of transcription causes accelerated nuclear egress of TDP-43, suggesting that newly synthesized RNA retains TDP-43 in the nucleus, limiting its egress into the cytoplasm. Our findings implicate reduced nuclear retention as a possible factor contributing to mislocalization of TDP-43 in ALS/FTD.
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Affiliation(s)
- Helena Ederle
- BioMedical Center (BMC), Cell Biology, Ludwig-Maximilians-University Munich, 82152, Planegg-Martinsried, Germany
- Graduate School of Systemic Neurosciences (GSN), 82152, Planegg-Martinsried, Germany
| | - Christina Funk
- Institute for Interfacial Engineering and Plasma Technology IGVP, University of Stuttgart, 70569, Stuttgart, Germany
- Frauenhofer Institute for Interfacial Engineering and Biotechnology, 70569, Stuttgart, Germany
| | - Claudia Abou-Ajram
- BioMedical Center (BMC), Cell Biology, Ludwig-Maximilians-University Munich, 82152, Planegg-Martinsried, Germany
| | - Saskia Hutten
- BioMedical Center (BMC), Cell Biology, Ludwig-Maximilians-University Munich, 82152, Planegg-Martinsried, Germany
| | - Eva B E Funk
- BioMedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, 81377, Munich, Germany
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Humboldtallee 23, 37073, Göttingen, Germany
| | - Susanne M Bailer
- Institute for Interfacial Engineering and Plasma Technology IGVP, University of Stuttgart, 70569, Stuttgart, Germany
- Frauenhofer Institute for Interfacial Engineering and Biotechnology, 70569, Stuttgart, Germany
| | - Dorothee Dormann
- BioMedical Center (BMC), Cell Biology, Ludwig-Maximilians-University Munich, 82152, Planegg-Martinsried, Germany.
- Graduate School of Systemic Neurosciences (GSN), 82152, Planegg-Martinsried, Germany.
- Munich Cluster for Systems Neurology (SyNergy), 81377, Munich, Germany.
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37
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St George-Hyslop P, Lin JQ, Miyashita A, Phillips EC, Qamar S, Randle SJ, Wang G. The physiological and pathological biophysics of phase separation and gelation of RNA binding proteins in amyotrophic lateral sclerosis and fronto-temporal lobar degeneration. Brain Res 2018; 1693:11-23. [PMID: 29723523 PMCID: PMC6018615 DOI: 10.1016/j.brainres.2018.04.036] [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: 02/20/2018] [Revised: 04/27/2018] [Accepted: 04/28/2018] [Indexed: 12/12/2022]
Abstract
Some intrinsically disordered proteins undergo reversible phase separation/gelation. Reversible phase separation/gelation underpins function of membraneless organelles. fALS-FUS mutations increase propensity of FUS to form highly stable condensates. Changes in arginine methylation and FUS chaperones in FTLD-FUS have similar effects. Stable fibrillar condensates sequester cargo and impair RNP granule function.
Many RNA binding proteins, including FUS, contain moderately repetitive, low complexity, intrinsically disordered domains. These sequence motifs have recently been found to underpin reversible liquid: liquid phase separation and gelation of these proteins, permitting them to reversibly transition from a monodispersed state to liquid droplet- or hydrogel-like states. This function allows the proteins to serve as scaffolds for the formation of reversible membraneless intracellular organelles such as nucleoli, stress granules and neuronal transport granules. Using FUS as an example, this review examines the biophysics of this physiological process, and reports on how mutations and changes in post-translational state alter phase behaviour, and lead to neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration.
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Affiliation(s)
- Peter St George-Hyslop
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK; Tanz Centre for Research in Neurodegenerative Diseases, and Departments of Medicine, Medical Biophysics and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 3H2, Canada.
| | - Julie Qiaojin Lin
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Akinori Miyashita
- Tanz Centre for Research in Neurodegenerative Diseases, and Departments of Medicine, Medical Biophysics and Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 3H2, Canada
| | - Emma C Phillips
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
| | - Seema Qamar
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
| | - Suzanne J Randle
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
| | - GuoZhen Wang
- Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0XY, UK
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38
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Synaptic Paths to Neurodegeneration: The Emerging Role of TDP-43 and FUS in Synaptic Functions. Neural Plast 2018; 2018:8413496. [PMID: 29755516 PMCID: PMC5925147 DOI: 10.1155/2018/8413496] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 02/08/2018] [Accepted: 02/27/2018] [Indexed: 12/13/2022] Open
Abstract
TAR DNA-binding protein-43 KDa (TDP-43) and fused in sarcoma (FUS) as the defining pathological hallmarks for amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), coupled with ALS-FTD-causing mutations in both genes, indicate that their dysfunctions damage the motor system and cognition. On the molecular level, TDP-43 and FUS participate in the biogenesis and metabolism of coding and noncoding RNAs as well as in the transport and translation of mRNAs as part of cytoplasmic mRNA-ribonucleoprotein (mRNP) granules. Intriguingly, many of the RNA targets of TDP-43 and FUS are involved in synaptic transmission and plasticity, indicating that synaptic dysfunction could be an early event contributing to motor and cognitive deficits in ALS and FTD. Furthermore, the ability of the low-complexity prion-like domains of TDP-43 and FUS to form liquid droplets suggests a potential mechanism for mRNP assembly and conversion. This review will discuss the role of TDP-43 and FUS in RNA metabolism, with an emphasis on the involvement of this process in synaptic function and neuroprotection. This will be followed by a discussion of the potential phase separation mechanism for forming RNP granules and pathological inclusions.
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Neuronal RNP granules: from physiological to pathological assemblies. Biol Chem 2018; 399:623-635. [DOI: 10.1515/hsz-2018-0141] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 03/30/2018] [Indexed: 12/11/2022]
Abstract
Abstract
Neuronal cells rely on macro- and micro-cellular compartmentalization to rapidly process information, and respond locally to external stimuli. Such a cellular organization is achieved via the assembly of neuronal ribonucleoprotein (RNP) granules, dynamic membrane-less organelles enriched in RNAs and associated regulatory proteins. In this review, we discuss how these high-order structures transport mRNAs to dendrites and axons, and how they contribute to the spatio-temporal regulation of localized mRNA translation. We also highlight how recent biophysical studies have shed light on the mechanisms underlying neuronal RNP granule dynamic assembly, remodeling and maturation, in both physiological and pathological contexts.
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40
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41
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Uversky VN. The roles of intrinsic disorder-based liquid-liquid phase transitions in the "Dr. Jekyll-Mr. Hyde" behavior of proteins involved in amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Autophagy 2017; 13:2115-2162. [PMID: 28980860 DOI: 10.1080/15548627.2017.1384889] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Pathological developments leading to amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) are associated with misbehavior of several key proteins, such as SOD1 (superoxide dismutase 1), TARDBP/TDP-43, FUS, C9orf72, and dipeptide repeat proteins generated as a result of the translation of the intronic hexanucleotide expansions in the C9orf72 gene, PFN1 (profilin 1), GLE1 (GLE1, RNA export mediator), PURA (purine rich element binding protein A), FLCN (folliculin), RBM45 (RNA binding motif protein 45), SS18L1/CREST, HNRNPA1 (heterogeneous nuclear ribonucleoprotein A1), HNRNPA2B1 (heterogeneous nuclear ribonucleoprotein A2/B1), ATXN2 (ataxin 2), MAPT (microtubule associated protein tau), and TIA1 (TIA1 cytotoxic granule associated RNA binding protein). Although these proteins are structurally and functionally different and have rather different pathological functions, they all possess some levels of intrinsic disorder and are either directly engaged in or are at least related to the physiological liquid-liquid phase transitions (LLPTs) leading to the formation of various proteinaceous membrane-less organelles (PMLOs), both normal and pathological. This review describes the normal and pathological functions of these ALS- and FTLD-related proteins, describes their major structural properties, glances at their intrinsic disorder status, and analyzes the involvement of these proteins in the formation of normal and pathological PMLOs, with the ultimate goal of better understanding the roles of LLPTs and intrinsic disorder in the "Dr. Jekyll-Mr. Hyde" behavior of those proteins.
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Affiliation(s)
- Vladimir N Uversky
- a Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute , Morsani College of Medicine , University of South Florida , Tampa , FL , USA.,b Institute for Biological Instrumentation of the Russian Academy of Sciences , Pushchino, Moscow region , Russia
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42
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Stress Granules Contain Rbfox2 with Cell Cycle-related mRNAs. Sci Rep 2017; 7:11211. [PMID: 28894257 PMCID: PMC5593835 DOI: 10.1038/s41598-017-11651-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/25/2017] [Indexed: 01/02/2023] Open
Abstract
Rbfox RNA-binding proteins play important roles in the regulation of alternative pre-mRNA splicing, but their role in other gene regulatory mechanisms is not well understood. Here, we show that Rbfox2 is a novel constituent of cytoplasmic stress granules, the translational silencing machinery assembled in response to cellular stress. We also show that the RNA binding activity of the Rbfox family protein is crucial for its localization into stress granules. To investigate the role of Rbfox2 in stress granules we used RNA-immunoprecipitation sequencing to identify cytoplasmic transcriptome-wide targets of Rbfox2. We report that a subset of cell cycle-related genes including retinoblastoma 1 is the target of Rbfox2 in cytoplasmic stress granules, and Rbfox2 regulates the retinoblastoma 1 mRNA and protein expression levels during and following stress exposure. Our study proposes a novel function for Rbfox2 in cytoplasmic stress granules.
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43
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Platelet phosphorylated TDP-43: an exploratory study for a peripheral surrogate biomarker development for Alzheimer's disease. Future Sci OA 2017; 3:FSO238. [PMID: 29134122 PMCID: PMC5674277 DOI: 10.4155/fsoa-2017-0090] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 07/28/2017] [Indexed: 12/13/2022] Open
Abstract
Aim: Alzheimer's disease (AD) and other forms of dementia create a noncurable disease population in world's societies. To develop a blood-based biomarker is important so that the remedial or disease-altering therapeutic intervention for AD patients would be available at the early stage. Materials & methods: TDP-43 levels were analyzed in postmortem brain tissue and platelets of AD and control subjects. Results: We observed an increased TDP-43 (<60%) in postmortem AD brain regions and similar trends were also observed in patient's platelets. Conclusion: Platelet TDP-43 could be used as a surrogate biomarker that is measurable, reproducible and sensitive for screening the patients with some early clinical signs of AD and can be used to monitor disease prognosis. In this study, we explore to identify an Alzheimer's disease (AD)-selective phospho-specific antibody that recognizes the diseased form of TDP-43 protein in patient's blood-derived platelets. Our results suggest that selective antiphosphorylated TDP-43 antibody discriminates AD from non-demented controls and patients with amyotrophic lateral sclerosis. Therefore, platelet screening with a selective antibody could potentially be a useful tool for diagnostic purposes for AD.
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44
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Monahan Z, Ryan VH, Janke AM, Burke KA, Rhoads SN, Zerze GH, O'Meally R, Dignon GL, Conicella AE, Zheng W, Best RB, Cole RN, Mittal J, Shewmaker F, Fawzi NL. Phosphorylation of the FUS low-complexity domain disrupts phase separation, aggregation, and toxicity. EMBO J 2017; 36:2951-2967. [PMID: 28790177 PMCID: PMC5641905 DOI: 10.15252/embj.201696394] [Citation(s) in RCA: 474] [Impact Index Per Article: 67.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 07/06/2017] [Accepted: 07/07/2017] [Indexed: 12/13/2022] Open
Abstract
Neuronal inclusions of aggregated RNA‐binding protein fused in sarcoma (FUS) are hallmarks of ALS and frontotemporal dementia subtypes. Intriguingly, FUS's nearly uncharged, aggregation‐prone, yeast prion‐like, low sequence‐complexity domain (LC) is known to be targeted for phosphorylation. Here we map in vitro and in‐cell phosphorylation sites across FUS LC. We show that both phosphorylation and phosphomimetic variants reduce its aggregation‐prone/prion‐like character, disrupting FUS phase separation in the presence of RNA or salt and reducing FUS propensity to aggregate. Nuclear magnetic resonance spectroscopy demonstrates the intrinsically disordered structure of FUS LC is preserved after phosphorylation; however, transient domain collapse and self‐interaction are reduced by phosphomimetics. Moreover, we show that phosphomimetic FUS reduces aggregation in human and yeast cell models, and can ameliorate FUS‐associated cytotoxicity. Hence, post‐translational modification may be a mechanism by which cells control physiological assembly and prevent pathological protein aggregation, suggesting a potential treatment pathway amenable to pharmacologic modulation.
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Affiliation(s)
- Zachary Monahan
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University, Bethesda, MD, USA
| | - Veronica H Ryan
- Neuroscience Graduate Program, Brown University, Providence, RI, USA
| | - Abigail M Janke
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI, USA
| | - Kathleen A Burke
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI, USA
| | - Shannon N Rhoads
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University, Bethesda, MD, USA
| | - Gül H Zerze
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, USA
| | - Robert O'Meally
- Johns Hopkins Mass Spectrometry and Proteomic Facility, Johns Hopkins University, Baltimore, MD, USA
| | - Gregory L Dignon
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, USA
| | - Alexander E Conicella
- Graduate Program in Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
| | - Wenwei Zheng
- Laboratory of Chemical Physics, National Institutes of Health, Bethesda, MD, USA
| | - Robert B Best
- Laboratory of Chemical Physics, National Institutes of Health, Bethesda, MD, USA
| | - Robert N Cole
- Johns Hopkins Mass Spectrometry and Proteomic Facility, Johns Hopkins University, Baltimore, MD, USA
| | - Jeetain Mittal
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA, USA
| | - Frank Shewmaker
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University, Bethesda, MD, USA
| | - Nicolas L Fawzi
- Neuroscience Graduate Program, Brown University, Providence, RI, USA .,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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45
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Haass C, Neumann M. Frontotemporal dementia: from molecular mechanisms to therapy. J Neurochem 2017; 138 Suppl 1:3-5. [PMID: 27502123 DOI: 10.1111/jnc.13619] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 03/11/2016] [Accepted: 03/12/2016] [Indexed: 12/14/2022]
Abstract
Frontotemporal dementia (FTD) is a heterogeneous clinical syndrome characterized by frontotemporal lobar degeneration (FTLD). Neuropathologically, FTLD is characterized by abnormal protein deposits and almost all cases can now be classified into three major molecular subgroups based on specific accumulating proteins with the most common being FTLD-tau and FTLD-TDP (accounting for ~40% and 50%, respectively) and FTLD-FET (accounting for ~5-10%). In this special issue, the molecular and genetic basics as well as clinical approaches and therapeutics are reviewed in a series of articles. This article is part of the Frontotemporal Dementia special issue.
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Affiliation(s)
- Christian Haass
- BioMedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE) Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Manuela Neumann
- Department for Neuropathology, University Hospital of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE) Tübingen, Tübingen, Germany
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46
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Scekic-Zahirovic J, Oussini HE, Mersmann S, Drenner K, Wagner M, Sun Y, Allmeroth K, Dieterlé S, Sinniger J, Dirrig-Grosch S, René F, Dormann D, Haass C, Ludolph AC, Lagier-Tourenne C, Storkebaum E, Dupuis L. Motor neuron intrinsic and extrinsic mechanisms contribute to the pathogenesis of FUS-associated amyotrophic lateral sclerosis. Acta Neuropathol 2017; 133:887-906. [PMID: 28243725 PMCID: PMC5427169 DOI: 10.1007/s00401-017-1687-9] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/08/2017] [Accepted: 02/16/2017] [Indexed: 12/11/2022]
Abstract
Motor neuron-extrinsic mechanisms have been shown to participate in the pathogenesis of ALS-SOD1, one familial form of amyotrophic lateral sclerosis (ALS). It remains unclear whether such mechanisms contribute to other familial forms, such as TDP-43 and FUS-associated ALS. Here, we characterize a single-copy mouse model of ALS-FUS that conditionally expresses a disease-relevant truncating FUS mutant from the endogenous murine Fus gene. We show that these mice, but not mice heterozygous for a Fus null allele, develop similar pathology as ALS-FUS patients and a mild motor neuron phenotype. Most importantly, CRE-mediated rescue of the Fus mutation within motor neurons prevented degeneration of motor neuron cell bodies, but only delayed appearance of motor symptoms. Indeed, we observed downregulation of multiple myelin-related genes, and increased numbers of oligodendrocytes in the spinal cord supporting their contribution to behavioral deficits. In all, we show that mutant FUS triggers toxic events in both motor neurons and neighboring cells to elicit motor neuron disease.
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47
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Sudhakaran IP, Ramaswami M. Long-term memory consolidation: The role of RNA-binding proteins with prion-like domains. RNA Biol 2017; 14:568-586. [PMID: 27726526 PMCID: PMC5449092 DOI: 10.1080/15476286.2016.1244588] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 09/07/2016] [Accepted: 09/29/2016] [Indexed: 12/23/2022] Open
Abstract
Long-term and short-term memories differ primarily in the duration of their retention. At a molecular level, long-term memory (LTM) is distinguished from short-term memory (STM) by its requirement for new gene expression. In addition to transcription (nuclear gene expression) the translation of stored mRNAs is necessary for LTM formation. The mechanisms and functions for temporal and spatial regulation of mRNAs required for LTM is a major contemporary problem, of interest from molecular, cell biological, neurobiological and clinical perspectives. This review discusses primary evidence in support for translational regulatory events involved in LTM and a model in which different phases of translation underlie distinct phases of consolidation of memories. However, it focuses largely on mechanisms of memory persistence and the role of prion-like domains in this defining aspect of long-term memory. We consider primary evidence for the concept that Cytoplasmic Polyadenylation Element Binding (CPEB) protein enables the persistence of formed memories by transforming in prion-like manner from a soluble monomeric state to a self-perpetuating and persistent polymeric translationally active state required for maintaining persistent synaptic plasticity. We further discuss prion-like domains prevalent on several other RNA-binding proteins involved in neuronal translational control underlying LTM. Growing evidence indicates that such RNA regulatory proteins are components of mRNP (RiboNucleoProtein) granules. In these proteins, prion-like domains, being intrinsically disordered, could mediate weak transient interactions that allow the assembly of RNP granules, a source of silenced mRNAs whose translation is necessary for LTM. We consider the structural bases for RNA granules formation as well as functions of disordered domains and discuss how these complicate the interpretation of existing experimental data relevant to general mechanisms by which prion-domain containing RBPs function in synapse specific plasticity underlying LTM.
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Affiliation(s)
- Indulekha P. Sudhakaran
- National Center for Biological Sciences, TIFR, Bangalore, India
- Manipal University, Manipal, India
| | - Mani Ramaswami
- National Center for Biological Sciences, TIFR, Bangalore, India
- School of Genetics and Microbiology and School of Natural Sciences, Smurfit Institute of Genetics and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
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48
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Ederle H, Dormann D. TDP-43 and FUS en route from the nucleus to the cytoplasm. FEBS Lett 2017; 591:1489-1507. [PMID: 28380257 DOI: 10.1002/1873-3468.12646] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 03/24/2017] [Accepted: 04/02/2017] [Indexed: 12/13/2022]
Abstract
Misfolded or mislocalized RNA-binding proteins (RBPs) and, consequently, altered mRNA processing, can cause neuronal dysfunction, eventually leading to neurodegeneration. Two prominent examples are the RBPs TAR DNA-binding protein of 43 kDa (TDP-43) and fused in sarcoma (FUS), which form pathological messenger ribonucleoprotein aggregates in patients suffering from amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), two devastating neurodegenerative disorders. Here, we review the multiple functions of TDP-43 and FUS in mRNA processing, both in the nucleus and in the cytoplasm. We discuss how TDP-43 and FUS may exit the nucleus and how defects in both nuclear and cytosolic mRNA processing events, and possibly nuclear export defects, may contribute to neurodegeneration and ALS/FTD pathogenesis.
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Affiliation(s)
- Helena Ederle
- BioMedical Center (BMC), Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany.,Graduate School of Systemic Neurosciences (GSN), Planegg-Martinsried, Germany
| | - Dorothee Dormann
- BioMedical Center (BMC), Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany.,Graduate School of Systemic Neurosciences (GSN), Planegg-Martinsried, Germany.,Munich Cluster for Systems Neurology (SyNergy), Germany
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49
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Lu Y, Lim L, Song J. RRM domain of ALS/FTD-causing FUS characteristic of irreversible unfolding spontaneously self-assembles into amyloid fibrils. Sci Rep 2017; 7:1043. [PMID: 28432364 PMCID: PMC5430844 DOI: 10.1038/s41598-017-01281-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/24/2017] [Indexed: 12/22/2022] Open
Abstract
526-residue FUS functions to self-assemble into reversible droplets/hydrogels, which could be further solidified into pathological fibrils. FUS is intrinsically prone to aggregation, composed of N-terminal low-sequence complexity (LC); RNA-recognition motif (RRM) and C-terminal LC domains. Intriguingly, previous in vivo studies revealed that its RRM is required for manifesting FUS cytotoxicity but the underlying mechanism remains unknown. Here, we characterized solution conformations of FUS and its five differentially dissected fragments, followed by detailed investigations on thermal unfolding, NMR dynamics and self-assembly of RRM. The results decipher: (1) the N- and C-terminal LC domains are intrinsically disordered, while RRM is folded. Intriguingly, well-dispersed HSQC peaks of RRM disappear in the full-length FUS, reminiscent of the previous observation on TDP-43. (2) FUS RRM is characteristic of irreversible unfolding. “Model-free” analysis of NMR relaxation data decodes that RRM has high ps-ns conformational dynamics even over some residues within secondary structure regions. (3) RRM spontaneously self-assembles into amyloid fibrils. Therefore, in addition to the well-established prion-like region, FUS RRM is also prone to self-assembly to form amyloid fibrils. Taken together, FUS RRM appears to play a crucial role in exaggerating the physiological/reversible self-assembly into pathological/irreversible fibrillization, thus contributing to manifestation of FUS cytotoxicity.
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Affiliation(s)
- Yimei Lu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 10 Kent Ridge Crescent, 119260, Singapore, Singapore
| | - Liangzhong Lim
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 10 Kent Ridge Crescent, 119260, Singapore, Singapore
| | - Jianxing Song
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 10 Kent Ridge Crescent, 119260, Singapore, Singapore.
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50
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Lo Piccolo L, Yamaguchi M. RNAi of arcRNA hsrω affects sub-cellular localization of Drosophila FUS to drive neurodiseases. Exp Neurol 2017; 292:125-134. [PMID: 28342748 DOI: 10.1016/j.expneurol.2017.03.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 03/01/2017] [Accepted: 03/21/2017] [Indexed: 02/08/2023]
Abstract
Defective RNA metabolism is common pathogenic mechanisms involved in neurological disorders. Indeed, a conspicuous feature of some neurodegenerative diseases is the loss of nuclear activities of RNA-binding proteins (RBPs) like Fused in sarcoma (FUS) and eventually, their accumulation in cytoplasmic proteinaceous inclusions. Long non-coding RNAs (lncRNAs) are emerging as important regulators of tissue physiology and disease processes, including neurological disorders. A subset of these lncRNAs is the core of nuclear bodies (NBs), which are the sites of RNA processing and sequestration of specific ribonucleoproteins (RNPs) complexes. In Drosophila melanogaster the lncRNA hsrω is the architectural RNA (arcRNA) of the NB omega speckles (ω-speckles). Here, we show that the neuron-specific and motor neuron-specific knockdown of hsrω impairs locomotion in larval and adult flies and induces anatomical defects in presynaptic terminals of motor neurons, suggesting a novel role of arcRNA hsrω in development of neuromuscular junctions. Since RBPs are recognized as important regulators of neuronal activities, to examine the molecular mechanism of such neurodegeneration, we analysed interaction between hsrω and Drosophila orthologue of human FUS (dFUS). Strictly, we found that dFUS genetically and physically interacts with the arcRNA hsrω. Moreover, we revealed that a fine regulation of gene expression occurs between hsrω and dFUS and surprisingly, we uncover that depletion of hsrω affects the sub-cellular compartmentalization of dFUS thus, enhancing its cytoplasmic localization and inducing its loss of nuclear function. The model we propose shows the role of arcRNA in diseases affecting the nervous system and in particular it elucidates the molecular mechanism underlying the loss of dFUS nuclear function in the absence of its mutations. Our new findings could provide new insights into the pathogenesis of neurodegenerative disease dependent on mis-function or mis-localization of aggregation prone RNA binding proteins like FUS in Amyotrophic Lateral Sclerosis.
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Affiliation(s)
- Luca Lo Piccolo
- Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
| | - Masamitsu Yamaguchi
- Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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