1
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Song J. Molecular Mechanisms of Phase Separation and Amyloidosis of ALS/FTD-linked FUS and TDP-43. Aging Dis 2024; 15:2084-2112. [PMID: 38029395 PMCID: PMC11346406 DOI: 10.14336/ad.2023.1118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/18/2023] [Indexed: 12/01/2023] Open
Abstract
FUS and TDP-43, two RNA-binding proteins from the heterogeneous nuclear ribonucleoprotein family, have gained significant attention in the field of neurodegenerative diseases due to their association with amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD). They possess folded domains for binding ATP and various nucleic acids including DNA and RNA, as well as substantial intrinsically disordered regions (IDRs) including prion-like domains (PLDs) and RG-/RGG-rich regions. They play vital roles in various cellular processes, including transcription, splicing, microRNA maturation, RNA stability and transport and DNA repair. In particular, they are key components for forming ribonucleoprotein granules and stress granules (SGs) through homotypic or heterotypic liquid-liquid phase separation (LLPS). Strikingly, liquid-like droplets formed by FUS and TDP-43 may undergo aging to transform into less dynamic assemblies such as hydrogels, inclusions, and amyloid fibrils, which are the pathological hallmarks of ALS and FTD. This review aims to synthesize and consolidate the biophysical knowledge of the sequences, structures, stability, dynamics, and inter-domain interactions of FUS and TDP-43 domains, so as to shed light on the molecular mechanisms underlying their liquid-liquid phase separation (LLPS) and amyloidosis. The review further delves into the mechanisms through which ALS-causing mutants of the well-folded hPFN1 disrupt the dynamics of LLPS of FUS prion-like domain, providing key insights into a potential mechanism for misfolding/aggregation-prone proteins to cause neurodegenerative diseases and aging by gain of functions. With better understanding of different biophysical aspects of FUS and TDP-43, the ultimate goal is to develop drugs targeting LLPS and amyloidosis, which could mediate protein homeostasis within cells and lead to new treatments for currently intractable diseases, particularly neurodegenerative diseases such as ALS, FTD and aging. However, the study of membrane-less organelles and condensates is still in its infancy and therefore the review also highlights key questions that require future investigation.
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2
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Kisby GE, Wilson DM, Spencer PS. Introducing the Role of Genotoxicity in Neurodegenerative Diseases and Neuropsychiatric Disorders. Int J Mol Sci 2024; 25:7221. [PMID: 39000326 PMCID: PMC11241460 DOI: 10.3390/ijms25137221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 06/21/2024] [Accepted: 06/27/2024] [Indexed: 07/16/2024] Open
Abstract
Decades of research have identified genetic and environmental factors involved in age-related neurodegenerative diseases and, to a lesser extent, neuropsychiatric disorders. Genomic instability, i.e., the loss of genome integrity, is a common feature among both neurodegenerative (mayo-trophic lateral sclerosis, Parkinson's disease, Alzheimer's disease) and psychiatric (schizophrenia, autism, bipolar depression) disorders. Genomic instability is associated with the accumulation of persistent DNA damage and the activation of DNA damage response (DDR) pathways, as well as pathologic neuronal cell loss or senescence. Typically, DDR signaling ensures that genomic and proteomic homeostasis are maintained in both dividing cells, including neural progenitors, and post-mitotic neurons. However, dysregulation of these protective responses, in part due to aging or environmental insults, contributes to the progressive development of neurodegenerative and/or psychiatric disorders. In this Special Issue, we introduce and highlight the overlap between neurodegenerative diseases and neuropsychiatric disorders, as well as the emerging clinical, genomic, and molecular evidence for the contributions of DNA damage and aberrant DNA repair. Our goal is to illuminate the importance of this subject to uncover possible treatment and prevention strategies for relevant devastating brain diseases.
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Affiliation(s)
- Glen E. Kisby
- Department of Biomedical Sciences, College of Osteopathic Medicine of Pacific Northwest, Western University of Health Sciences, Lebanon, OR 97355, USA
| | - David M. Wilson
- Biomedical Research Institute, BIOMED, Hasselt University, 3500 Hasselt, Belgium;
| | - Peter S. Spencer
- Department of Neurology, School of Medicine, Oregon Institute of Occupational Health Sciences, Oregon Health & Sciences University (OHSU), Portland, OR 97239, USA
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3
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Jagaraj CJ, Shadfar S, Kashani SA, Saravanabavan S, Farzana F, Atkin JD. Molecular hallmarks of ageing in amyotrophic lateral sclerosis. Cell Mol Life Sci 2024; 81:111. [PMID: 38430277 PMCID: PMC10908642 DOI: 10.1007/s00018-024-05164-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/21/2024] [Accepted: 02/06/2024] [Indexed: 03/03/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, severely debilitating and rapidly progressing disorder affecting motor neurons in the brain, brainstem, and spinal cord. Unfortunately, there are few effective treatments, thus there remains a critical need to find novel interventions that can mitigate against its effects. Whilst the aetiology of ALS remains unclear, ageing is the major risk factor. Ageing is a slowly progressive process marked by functional decline of an organism over its lifespan. However, it remains unclear how ageing promotes the risk of ALS. At the molecular and cellular level there are specific hallmarks characteristic of normal ageing. These hallmarks are highly inter-related and overlap significantly with each other. Moreover, whilst ageing is a normal process, there are striking similarities at the molecular level between these factors and neurodegeneration in ALS. Nine ageing hallmarks were originally proposed: genomic instability, loss of telomeres, senescence, epigenetic modifications, dysregulated nutrient sensing, loss of proteostasis, mitochondrial dysfunction, stem cell exhaustion, and altered inter-cellular communication. However, these were recently (2023) expanded to include dysregulation of autophagy, inflammation and dysbiosis. Hence, given the latest updates to these hallmarks, and their close association to disease processes in ALS, a new examination of their relationship to pathophysiology is warranted. In this review, we describe possible mechanisms by which normal ageing impacts on neurodegenerative mechanisms implicated in ALS, and new therapeutic interventions that may arise from this.
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Affiliation(s)
- Cyril Jones Jagaraj
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Sina Shadfar
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Sara Assar Kashani
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Sayanthooran Saravanabavan
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Fabiha Farzana
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Julie D Atkin
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia.
- La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne, VIC, 3086, Australia.
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4
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Demongin C, Tranier S, Joshi V, Ceschi L, Desforges B, Pastré D, Hamon L. RNA and the RNA-binding protein FUS act in concert to prevent TDP-43 spatial segregation. J Biol Chem 2024; 300:105716. [PMID: 38311174 PMCID: PMC10912363 DOI: 10.1016/j.jbc.2024.105716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 01/15/2024] [Accepted: 01/19/2024] [Indexed: 02/10/2024] Open
Abstract
FUS and TDP-43 are two self-adhesive aggregation-prone mRNA-binding proteins whose pathological mutations have been linked to neurodegeneration. While TDP-43 and FUS form reversible mRNA-rich compartments in the nucleus, pathological mutations promote their respective cytoplasmic aggregation in neurons with no apparent link between the two proteins except their intertwined function in mRNA processing. By combining analyses in cellular context and at high resolution in vitro, we unraveled that TDP-43 is specifically recruited in FUS assemblies to form TDP-43-rich subcompartments but without reciprocity. The presence of mRNA provides an additional scaffold to promote the mixing between TDP-43 and FUS. Accordingly, we also found that the pathological truncated form of TDP-43, TDP-25, which has an impaired RNA-binding ability, no longer mixes with FUS. Together, these results suggest that the binding of FUS along nascent mRNAs enables TDP-43, which is highly aggregation-prone, to mix with FUS phase to form mRNA-rich subcompartments. A functional link between FUS and TDP-43 may explain their common implication in amyotrophic lateral sclerosis.
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Affiliation(s)
- Clément Demongin
- SABNP, Univ Evry, INSERM, U1204, Université Paris-Saclay, Evry, France
| | - Samuel Tranier
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Vandana Joshi
- SABNP, Univ Evry, INSERM, U1204, Université Paris-Saclay, Evry, France
| | - Léa Ceschi
- SABNP, Univ Evry, INSERM, U1204, Université Paris-Saclay, Evry, France
| | | | - David Pastré
- SABNP, Univ Evry, INSERM, U1204, Université Paris-Saclay, Evry, France
| | - Loic Hamon
- SABNP, Univ Evry, INSERM, U1204, Université Paris-Saclay, Evry, France.
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5
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Dey B, Kumar A, Patel AB. Pathomechanistic Networks of Motor System Injury in Amyotrophic Lateral Sclerosis. Curr Neuropharmacol 2024; 22:1778-1806. [PMID: 37622689 PMCID: PMC11284732 DOI: 10.2174/1570159x21666230824091601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/25/2023] [Accepted: 06/06/2023] [Indexed: 08/26/2023] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is the most common, adult-onset, progressive motor neurodegenerative disorder that results in death within 3 years of the clinical diagnosis. Due to the clinicopathological heterogeneity, any reliable biomarkers for diagnosis or prognosis of ALS have not been identified till date. Moreover, the only three clinically approved treatments are not uniformly effective in slowing the disease progression. Over the last 15 years, there has been a rapid advancement in research on the complex pathomechanistic landscape of ALS that has opened up new avenues for successful clinical translation of targeted therapeutics. Multiple studies suggest that the age-dependent interaction of risk-associated genes with environmental factors and endogenous modifiers is critical to the multi-step process of ALS pathogenesis. In this review, we provide an updated discussion on the dysregulated cross-talk between intracellular homeostasis processes, the unique molecular networks across selectively vulnerable cell types, and the multisystemic nature of ALS pathomechanisms. Importantly, this work highlights the alteration in epigenetic and epitranscriptomic landscape due to gene-environment interactions, which have been largely overlooked in the context of ALS pathology. Finally, we suggest that precision medicine research in ALS will be largely benefitted from the stratification of patient groups based on the clinical phenotype, onset and progression, genome, exposome, and metabolic identities.
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Affiliation(s)
- Bedaballi Dey
- CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad 500007, Telangana, India
- AcSIR-Academy of Scientific and Innovative Research, Ghaziabad 201002, Uttar Pradesh, India
| | - Arvind Kumar
- CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad 500007, Telangana, India
- AcSIR-Academy of Scientific and Innovative Research, Ghaziabad 201002, Uttar Pradesh, India
| | - Anant Bahadur Patel
- CSIR-Centre for Cellular and Molecular Biology (CSIR-CCMB), Hyderabad 500007, Telangana, India
- AcSIR-Academy of Scientific and Innovative Research, Ghaziabad 201002, Uttar Pradesh, India
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6
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García Morato J, Gloeckner CJ, Kahle PJ. Proteomics elucidating physiological and pathological functions of TDP-43. Proteomics 2023; 23:e2200410. [PMID: 37671599 DOI: 10.1002/pmic.202200410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 08/02/2023] [Accepted: 08/10/2023] [Indexed: 09/07/2023]
Abstract
Trans-activation response DNA binding protein of 43 kDa (TDP-43) regulates a great variety of cellular processes in the nucleus and cytosol. In addition, a defined subset of neurodegenerative diseases is characterized by nuclear depletion of TDP-43 as well as cytosolic mislocalization and aggregation. To perform its diverse functions TDP-43 can associate with different ribonucleoprotein complexes. Combined with transcriptomics, MS interactome studies have unveiled associations between TDP-43 and the spliceosome machinery, polysomes and RNA granules. Moreover, the highly dynamic, low-valency interactions regulated by its low-complexity domain calls for innovative proximity labeling methodologies. In addition to protein partners, the analysis of post-translational modifications showed that they may play a role in the nucleocytoplasmic shuttling, RNA binding, liquid-liquid phase separation and protein aggregation of TDP-43. Here we review the various TDP-43 ribonucleoprotein complexes characterized so far, how they contribute to the diverse functions of TDP-43, and roles of post-translational modifications. Further understanding of the fluid dynamic properties of TDP-43 in ribonucleoprotein complexes, RNA granules, and self-assemblies will advance the understanding of RNA processing in cells and perhaps help to develop novel therapeutic approaches for TDPopathies.
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Affiliation(s)
- Jorge García Morato
- Laboratory of Functional Neurogenetics, Department of Neurodegeneration, German Center of Neurodegenerative Diseases and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Christian Johannes Gloeckner
- Research Group Functional Neuroproteomics, German Center of Neurodegenerative Diseases, Tübingen, Germany
- Core Facility for Medical Bioanalytics, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Philipp J Kahle
- Laboratory of Functional Neurogenetics, Department of Neurodegeneration, German Center of Neurodegenerative Diseases and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Department of Biochemistry, University of Tübingen, Tübingen, Germany
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7
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Kour S, Fortuna T, Anderson EN, Mawrie D, Bilstein J, Sivasubramanian R, Ward C, Roy R, Rajasundaram D, Sterneckert J, Pandey UB. Drosha-dependent microRNAs modulate FUS-mediated neurodegeneration in vivo. Nucleic Acids Res 2023; 51:11258-11276. [PMID: 37791873 PMCID: PMC10639082 DOI: 10.1093/nar/gkad774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 08/03/2023] [Accepted: 09/12/2023] [Indexed: 10/05/2023] Open
Abstract
Mutations in the Fused in Sarcoma (FUS) gene cause the familial and progressive form of amyotrophic lateral sclerosis (ALS). FUS is a nuclear RNA-binding protein involved in RNA processing and the biogenesis of a specific set of microRNAs. Here we report that Drosha and two previously uncharacterized Drosha-dependent miRNAs are strong modulators of FUS expression and prevent the cytoplasmic segregation of insoluble mutant FUS in vivo. We demonstrate that depletion of Drosha mitigates FUS-mediated degeneration, survival and motor defects in Drosophila. Mutant FUS strongly interacts with Drosha and causes its cytoplasmic mis-localization into the insoluble FUS inclusions. Reduction in Drosha levels increases the solubility of mutant FUS. Interestingly, we found two Drosha dependent microRNAs, miR-378i and miR-6832-5p, which differentially regulate the expression, solubility and cytoplasmic aggregation of mutant FUS in iPSC neurons and mammalian cells. More importantly, we report different modes of action of these miRNAs against mutant FUS. Whereas miR-378i may regulate mutant FUS inclusions by preventing G3BP-mediated stress granule formation, miR-6832-5p may affect FUS expression via other proteins or pathways. Overall, our research reveals a possible association between ALS-linked FUS mutations and the Drosha-dependent miRNA regulatory circuit, as well as a useful perspective on potential ALS treatment via microRNAs.
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Affiliation(s)
- Sukhleen Kour
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Tyler Fortuna
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Eric N Anderson
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Darilang Mawrie
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Jessica Bilstein
- Center for Regenerative Therapies TU Dresden (CRTD), Technische Universität (TU) Dresden, Dresden, 01307, Germany
| | - Ramakrishnan Sivasubramanian
- Center for Regenerative Therapies TU Dresden (CRTD), Technische Universität (TU) Dresden, Dresden, 01307, Germany
| | - Caroline Ward
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Rishit Roy
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
| | - Dhivyaa Rajasundaram
- Department of Pediatrics, Division of Health Informatics, Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Jared Sterneckert
- Center for Regenerative Therapies TU Dresden (CRTD), Technische Universität (TU) Dresden, Dresden, 01307, Germany
- Medical Faculty Carl Gustav Carus of TU Dresden, Dresden, 01307, Germany
| | - Udai Bhan Pandey
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
- Children's Neuroscience Institute, Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center, Pittsburgh, PA 15224, USA
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8
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Taylor M, Marx O, Norris A. TDP-1 and FUST-1 co-inhibit exon inclusion and control fertility together with transcriptional regulation. Nucleic Acids Res 2023; 51:9610-9628. [PMID: 37587694 PMCID: PMC10570059 DOI: 10.1093/nar/gkad665] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/20/2023] [Accepted: 08/09/2023] [Indexed: 08/18/2023] Open
Abstract
Gene expression is a multistep process and crosstalk among regulatory layers plays an important role in coordinating gene expression. To identify functionally relevant gene expression coordination, we performed a systematic reverse-genetic interaction screen in C. elegans, combining RNA binding protein (RBP) and transcription factor (TF) mutants to generate over 100 RBP;TF double mutants. We identified many unexpected double mutant phenotypes, including two strong genetic interactions between the ALS-related RBPs, fust-1 and tdp-1, and the homeodomain TF ceh-14. Losing any one of these genes alone has no effect on the health of the organism. However, fust-1;ceh-14 and tdp-1;ceh-14 double mutants both exhibit strong temperature-sensitive fertility defects. Both double mutants exhibit defects in gonad morphology, sperm function, and oocyte function. RNA-Seq analysis of double mutants identifies ceh-14 as the main controller of transcript levels, while fust-1 and tdp-1 control splicing through a shared role in exon inhibition. A skipped exon in the polyglutamine-repeat protein pqn-41 is aberrantly included in tdp-1 mutants, and genetically forcing this exon to be skipped in tdp-1;ceh-14 double mutants rescues their fertility. Together our findings identify a novel shared physiological role for fust-1 and tdp-1 in promoting C. elegans fertility and a shared molecular role in exon inhibition.
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Affiliation(s)
- Morgan Taylor
- Southern Methodist University, Dallas, TX 75205, USA
| | - Olivia Marx
- Southern Methodist University, Dallas, TX 75205, USA
| | - Adam Norris
- Southern Methodist University, Dallas, TX 75205, USA
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9
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Thompson VF, Wieland DR, Mendoza-Leon V, Janis HI, Lay MA, Harrell LM, Schwartz JC. Binding of the nuclear ribonucleoprotein family member FUS to RNA prevents R-loop RNA:DNA hybrid structures. J Biol Chem 2023; 299:105237. [PMID: 37690693 PMCID: PMC10556777 DOI: 10.1016/j.jbc.2023.105237] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 08/17/2023] [Accepted: 08/25/2023] [Indexed: 09/12/2023] Open
Abstract
The protein FUS (FUSed in sarcoma) is a metazoan RNA-binding protein that influences RNA production by all three nuclear polymerases. FUS also binds nascent transcripts, RNA processing factors, RNA polymerases, and transcription machinery. Here, we explored the role of FUS binding interactions for activity during transcription. In vitro run-off transcription assays revealed FUS-enhanced RNA produced by a non-eukaryote polymerase. The activity also reduced the formation of R-loops between RNA products and their DNA template. Analysis by domain mutation and deletion indicated RNA-binding was required for activity. We interpret that FUS binds and sequesters nascent transcripts to prevent R-loops from forming with nearby DNA. DRIP-seq analysis showed that a knockdown of FUS increased R-loop enrichment near expressed genes. Prevention of R-loops by FUS binding to nascent transcripts has the potential to affect transcription by any RNA polymerase, highlighting the broad impact FUS can have on RNA metabolism in cells and disease.
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Affiliation(s)
- Valery F Thompson
- Department of Pharmacology, University of Arizona, Tucson, Arizona, USA; University of Arizona Cancer Center, Tucson, Arizona, USA
| | - Daniel R Wieland
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Vivian Mendoza-Leon
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Helen I Janis
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Michelle A Lay
- Department of Pharmacology, University of Arizona, Tucson, Arizona, USA; University of Arizona Cancer Center, Tucson, Arizona, USA; Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Lucas M Harrell
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Jacob C Schwartz
- Department of Pharmacology, University of Arizona, Tucson, Arizona, USA; University of Arizona Cancer Center, Tucson, Arizona, USA.
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10
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Gimenez J, Spalloni A, Cappelli S, Ciaiola F, Orlando V, Buratti E, Longone P. TDP-43 Epigenetic Facets and Their Neurodegenerative Implications. Int J Mol Sci 2023; 24:13807. [PMID: 37762112 PMCID: PMC10530927 DOI: 10.3390/ijms241813807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 07/31/2023] [Accepted: 08/09/2023] [Indexed: 09/29/2023] Open
Abstract
Since its initial involvement in numerous neurodegenerative pathologies in 2006, either as a principal actor or as a cofactor, new pathologies implicating transactive response (TAR) DNA-binding protein 43 (TDP-43) are regularly emerging also beyond the neuronal system. This reflects the fact that TDP-43 functions are particularly complex and broad in a great variety of human cells. In neurodegenerative diseases, this protein is often pathologically delocalized to the cytoplasm, where it irreversibly aggregates and is subjected to various post-translational modifications such as phosphorylation, polyubiquitination, and cleavage. Until a few years ago, the research emphasis has been focused particularly on the impacts of this aggregation and/or on its widely described role in complex RNA splicing, whether related to loss- or gain-of-function mechanisms. Interestingly, recent studies have strengthened the knowledge of TDP-43 activity at the chromatin level and its implication in the regulation of DNA transcription and stability. These discoveries have highlighted new features regarding its own transcriptional regulation and suggested additional mechanistic and disease models for the effects of TPD-43. In this review, we aim to give a comprehensive view of the potential epigenetic (de)regulations driven by (and driving) this multitask DNA/RNA-binding protein.
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Affiliation(s)
- Juliette Gimenez
- Molecular Neurobiology Laboratory, Experimental Neuroscience, IRCCS Fondazione Santa Lucia (FSL), 00143 Rome, Italy; (A.S.); (P.L.)
| | - Alida Spalloni
- Molecular Neurobiology Laboratory, Experimental Neuroscience, IRCCS Fondazione Santa Lucia (FSL), 00143 Rome, Italy; (A.S.); (P.L.)
| | - Sara Cappelli
- Molecular Pathology Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), 34149 Trieste, Italy; (S.C.); (E.B.)
| | - Francesca Ciaiola
- Molecular Neurobiology Laboratory, Experimental Neuroscience, IRCCS Fondazione Santa Lucia (FSL), 00143 Rome, Italy; (A.S.); (P.L.)
- Department of Systems Medicine, University of Roma Tor Vergata, 00133 Rome, Italy
| | - Valerio Orlando
- KAUST Environmental Epigenetics Program, Biological Environmental Sciences and Engineering Division BESE, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia;
| | - Emanuele Buratti
- Molecular Pathology Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), 34149 Trieste, Italy; (S.C.); (E.B.)
| | - Patrizia Longone
- Molecular Neurobiology Laboratory, Experimental Neuroscience, IRCCS Fondazione Santa Lucia (FSL), 00143 Rome, Italy; (A.S.); (P.L.)
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11
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Krupp S, Hubbard I, Tam O, Hammell GM, Dubnau J. TDP-43 pathology in Drosophila induces glial-cell type specific toxicity that can be ameliorated by knock-down of SF2/SRSF1. PLoS Genet 2023; 19:e1010973. [PMID: 37747929 PMCID: PMC10553832 DOI: 10.1371/journal.pgen.1010973] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 10/05/2023] [Accepted: 09/13/2023] [Indexed: 09/27/2023] Open
Abstract
Accumulation of cytoplasmic inclusions of TAR-DNA binding protein 43 (TDP-43) is seen in both neurons and glia in a range of neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD) and Alzheimer's disease (AD). Disease progression involves non-cell autonomous interactions among multiple cell types, including neurons, microglia and astrocytes. We investigated the effects in Drosophila of inducible, glial cell type-specific TDP-43 overexpression, a model that causes TDP-43 protein pathology including loss of nuclear TDP-43 and accumulation of cytoplasmic inclusions. We report that TDP-43 pathology in Drosophila is sufficient to cause progressive loss of each of the 5 glial sub-types. But the effects on organismal survival were most pronounced when TDP-43 pathology was induced in the perineural glia (PNG) or astrocytes. In the case of PNG, this effect is not attributable to loss of the glial population, because ablation of these glia by expression of pro-apoptotic reaper expression has relatively little impact on survival. To uncover underlying mechanisms, we used cell-type-specific nuclear RNA sequencing to characterize the transcriptional changes induced by pathological TDP-43 expression. We identified numerous glial cell-type specific transcriptional changes. Notably, SF2/SRSF1 levels were found to be decreased in both PNG and in astrocytes. We found that further knockdown of SF2/SRSF1 in either PNG or astrocytes lessens the detrimental effects of TDP-43 pathology on lifespan, but extends survival of the glial cells. Thus TDP-43 pathology in astrocytes or PNG causes systemic effects that shorten lifespan and SF2/SRSF1 knockdown rescues the loss of these glia, and also reduces their systemic toxicity to the organism.
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Affiliation(s)
- Sarah Krupp
- Program in Neuroscience, Department of Neurobiology and Behavior, Stony Brook University, New York, United States of America
| | - Isabel Hubbard
- Program in Neuroscience, Department of Neurobiology and Behavior, Stony Brook University, New York, United States of America
| | - Oliver Tam
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Gale M. Hammell
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Josh Dubnau
- Program in Neuroscience, Department of Neurobiology and Behavior, Stony Brook University, New York, United States of America
- Department of Anesthesiology, Stony Brook School of Medicine, New York, United States of America
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12
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Jung KH, Sun J, Hsiung CH, Lance Lian X, Liu Y, Zhang X. Nuclear bodies protect phase separated proteins from degradation in stressed proteome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.537522. [PMID: 37131610 PMCID: PMC10153235 DOI: 10.1101/2023.04.19.537522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
RNA-binding proteins (RBPs) containing intrinsically disordered domains undergo liquid-liquid phase separation to form nuclear bodies under stress conditions. This process is also connected to the misfolding and aggregation of RBPs, which are associated with a series of neurodegenerative diseases. However, it remains elusive how folding states of RBPs changes upon the formation and maturation of nuclear bodies. Here, we describe SNAP-tag based imaging methods to visualize the folding states of RBPs in live cells via time-resolved quantitative microscopic analyses of their micropolarity and microviscosity. Using these imaging methods in conjunction with immunofluorescence imaging, we demonstrate that RBPs, represented by TDP-43, initially enters the PML nuclear bodies in its native state upon transient proteostasis stress, albeit it begins to misfolded during prolonged stress. Furthermore, we show that heat shock protein 70 co-enters the PML nuclear bodies to prevent the degradation of TDP-43 from the proteotoxic stress, thus revealing a previously unappreciated protective role of the PML nuclear bodies in the prevention of stress-induced degradation of TDP-43. In summary, our imaging methods described in the manuscript, for the first time, reveal the folding states of RBPs, which were previously challenging to study with conventional methods in nuclear bodies of live cells. This study uncovers the mechanistic correlations between the folding states of a protein and functions of nuclear bodies, in particular PML bodies. We envision that the imaging methods can be generally applied to elucidating the structural aspects of other proteins that exhibit granular structures under biological stimulus.
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Affiliation(s)
- Kwan Ho Jung
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The Huck Institute of Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
| | - Jiarui Sun
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The Huck Institute of Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
| | - Chia-Heng Hsiung
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The Huck Institute of Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
- Present address: Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, 600 Dunyu Road, Hangzhou 310030, Zhejiang Province, China; Westlake Laboratory of Life Sciences and Biomedicine; 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
- Department of Biomedical Engineering, The Huck Institute of Life Sciences, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
| | - Xiaojun Lance Lian
- Department of Biomedical Engineering, The Huck Institute of Life Sciences, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
| | - Yu Liu
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, China
| | - Xin Zhang
- Department of Chemistry, Department of Biochemistry and Molecular Biology, The Huck Institute of Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
- Present address: Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, 600 Dunyu Road, Hangzhou 310030, Zhejiang Province, China; Westlake Laboratory of Life Sciences and Biomedicine; 18 Shilongshan Road, Hangzhou 310024, Zhejiang Province, China
- Department of Biomedical Engineering, The Huck Institute of Life Sciences, Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, 16802, United States
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13
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Taylor M, Marx O, Norris A. TDP-1 and FUST-1 co-inhibit exon inclusion and control fertility together with transcriptional regulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.18.537345. [PMID: 37131843 PMCID: PMC10153140 DOI: 10.1101/2023.04.18.537345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Gene expression is a multistep, carefully controlled process, and crosstalk between regulatory layers plays an important role in coordinating gene expression. To identify functionally relevant coordination between transcriptional and post-transcriptional gene regulation, we performed a systematic reverse-genetic interaction screen in C. elegans . We combined RNA binding protein (RBP) and transcription factor (TF) mutants, creating over 100 RBP; TF double mutants. This screen identified a variety of unexpected double mutant phenotypes, including two strong genetic interactions between the ALS-related RBPs, fust-1 and tdp-1 , and the homeodomain TF ceh-14 . Losing any one of these genes alone has no significant effect on the health of the organism. However, fust-1; ceh-14 and tdp-1; ceh-14 double mutants both exhibit strong temperature-sensitive fertility defects. Both double mutants exhibit defects in gonad morphology, sperm function, and oocyte function. RNA-seq analysis of double mutants identifies ceh-14 as the main controller of transcript levels, while fust-1 and tdp-1 control splicing through a shared role in exon inhibition. We identify a cassette exon in the polyglutamine-repeat protein pqn-41 which tdp-1 inhibits. Loss of tdp-1 causes the pqn-41 exon to be aberrantly included, and forced skipping of this exon in tdp-1; ceh-14 double mutants rescues fertility. Together our findings identify a novel shared physiological role for fust-1 and tdp-1 in promoting C. elegans fertility in a ceh-14 mutant background and reveal a shared molecular function of fust-1 and tdp-1 in exon inhibition.
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14
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Bernal AF, Mota N, Pamplona R, Area-Gomez E, Portero-Otin M. Hakuna MAM-Tata: Investigating the role of mitochondrial-associated membranes in ALS. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166716. [PMID: 37044239 DOI: 10.1016/j.bbadis.2023.166716] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 04/03/2023] [Indexed: 04/14/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease leading to selective and progressive motor neuron (MN) death. Despite significant heterogeneity in pathogenic and clinical terms, MN demise ultimately unifies patients. Across the many disturbances in neuronal biology present in the disease and its models, two common trends are loss of calcium homeostasis and dysregulations in lipid metabolism. Since both mitochondria and endoplasmic reticulum (ER) are essential in these functions, their intertwin through the so-called mitochondrial-associated membranes (MAMs) should be relevant in this disease. In this review, we present a short overview of MAMs functional aspects and how its dysfunction could explain a substantial part of the cellular disarrangements in ALS's natural history. MAMs are hubs for lipid synthesis, integrating glycerophospholipids, sphingolipids, and cholesteryl ester metabolism. These lipids are essential for membrane biology, so there should be a close coupling to cellular energy demands, a role that MAMs may partially fulfill. Not surprisingly, MAMs are also host part of calcium signaling to mitochondria, so their impairment could lead to mitochondrial dysfunction, affecting oxidative phosphorylation and enhancing the vulnerability of MNs. We present data supporting that MAMs' maladaptation could be essential to MNs' vulnerability in ALS.
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Affiliation(s)
- Anna Fernàndez Bernal
- Metabolic Pathophysiology Research Group, Department of Experimental Medicine, University of Lleida-IRBLleida, Edifici Biomedicina I, Avda Rovira Roure 80, E25196 Lleida, Spain.
| | - Natàlia Mota
- Metabolic Pathophysiology Research Group, Department of Experimental Medicine, University of Lleida-IRBLleida, Edifici Biomedicina I, Avda Rovira Roure 80, E25196 Lleida, Spain.
| | - Reinald Pamplona
- Metabolic Pathophysiology Research Group, Department of Experimental Medicine, University of Lleida-IRBLleida, Edifici Biomedicina I, Avda Rovira Roure 80, E25196 Lleida, Spain.
| | - Estela Area-Gomez
- Centro de Investigaciones Biológicas Margarita Salas CSIC, C. Ramiro de Maeztu, 9, 28040 Madrid, Spain.
| | - Manuel Portero-Otin
- Metabolic Pathophysiology Research Group, Department of Experimental Medicine, University of Lleida-IRBLleida, Edifici Biomedicina I, Avda Rovira Roure 80, E25196 Lleida, Spain.
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15
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Lépine S, Castellanos-Montiel MJ, Durcan TM. TDP-43 dysregulation and neuromuscular junction disruption in amyotrophic lateral sclerosis. Transl Neurodegener 2022; 11:56. [PMID: 36575535 PMCID: PMC9793560 DOI: 10.1186/s40035-022-00331-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/29/2022] [Indexed: 12/28/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a disease characterized by upper and lower motor neuron (MN) loss with a signature feature of cytoplasmic aggregates containing TDP-43, which are detected in nearly all patients. Mutations in the gene that encodes TDP-43 (TARBDP) are known to result in both familial and sporadic ALS. In ALS, disruption of neuromuscular junctions (NMJs) constitutes a critical event in disease pathogenesis, leading to denervation atrophy, motor impairments and disability. Morphological defects and impaired synaptic transmission at NMJs have been reported in several TDP-43 animal models and in vitro, linking TDP-43 dysregulation to the loss of NMJ integrity in ALS. Through the lens of the dying-back and dying-forward hypotheses of ALS, this review discusses the roles of TDP-43 related to synaptic function, with a focus on the potential molecular mechanisms occurring within MNs, skeletal muscles and glial cells that may contribute to NMJ disruption in ALS.
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Affiliation(s)
- Sarah Lépine
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada ,grid.14709.3b0000 0004 1936 8649Faculty of Medicine and Health Sciences, McGill University, 3605 De La Montagne, Montreal, QC H3G 2M1 Canada
| | - Maria José Castellanos-Montiel
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada
| | - Thomas Martin Durcan
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada
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16
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Multiple roles for the cytoskeleton in ALS. Exp Neurol 2022; 355:114143. [PMID: 35714755 PMCID: PMC10163623 DOI: 10.1016/j.expneurol.2022.114143] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 06/05/2022] [Accepted: 06/08/2022] [Indexed: 11/20/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease caused by more than sixty genes identified through classic linkage analysis and new sequencing methods. Yet no clear mechanism of onset, cure, or effective treatment is known. Popular discourse classifies the proteins encoded from ALS-related genes into four disrupted processes: proteostasis, mitochondrial function and ROS, nucleic acid regulation, and cytoskeletal dynamics. Surprisingly, the mechanisms detailing the contribution of the neuronal cytoskeletal in ALS are the least explored, despite involvement in these cell processes. Eight genes directly regulate properties of cytoskeleton function and are essential for the health and survival of motor neurons, including: TUBA4A, SPAST, KIF5A, DCTN1, NF, PRPH, ALS2, and PFN1. Here we review the properties and studies exploring the contribution of each of these genes to ALS.
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17
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Konopka A, Atkin JD. DNA Damage, Defective DNA Repair, and Neurodegeneration in Amyotrophic Lateral Sclerosis. Front Aging Neurosci 2022; 14:786420. [PMID: 35572138 PMCID: PMC9093740 DOI: 10.3389/fnagi.2022.786420] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 03/07/2022] [Indexed: 12/16/2022] Open
Abstract
DNA is under constant attack from both endogenous and exogenous sources, and when damaged, specific cellular signalling pathways respond, collectively termed the “DNA damage response.” Efficient DNA repair processes are essential for cellular viability, although they decline significantly during aging. Not surprisingly, DNA damage and defective DNA repair are now increasingly implicated in age-related neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). ALS affects both upper and lower motor neurons in the brain, brainstem and spinal cord, leading to muscle wasting due to denervation. DNA damage is increasingly implicated in the pathophysiology of ALS, and interestingly, the number of DNA damage or repair proteins linked to ALS is steadily growing. This includes TAR DNA binding protein 43 (TDP-43), a DNA/RNA binding protein that is present in a pathological form in almost all (97%) cases of ALS. Hence TDP-43 pathology is central to neurodegeneration in this condition. Fused in Sarcoma (FUS) bears structural and functional similarities to TDP-43 and it also functions in DNA repair. Chromosome 9 open reading frame 72 (C9orf72) is also fundamental to ALS because mutations in C9orf72 are the most frequent genetic cause of both ALS and related condition frontotemporal dementia, in European and North American populations. Genetic variants encoding other proteins involved in the DNA damage response (DDR) have also been described in ALS, including FUS, SOD1, SETX, VCP, CCNF, and NEK1. Here we review recent evidence highlighting DNA damage and defective DNA repair as an important mechanism linked to neurodegeneration in ALS.
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Affiliation(s)
- Anna Konopka
- Centre for Motor Neuron Disease Research, Faculty of Medicine, Macquarie Medical School, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
- *Correspondence: Anna Konopka,
| | - Julie D. Atkin
- Centre for Motor Neuron Disease Research, Faculty of Medicine, Macquarie Medical School, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
- Julie D. Atkin,
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18
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Provasek VE, Mitra J, Malojirao VH, Hegde ML. DNA Double-Strand Breaks as Pathogenic Lesions in Neurological Disorders. Int J Mol Sci 2022; 23:ijms23094653. [PMID: 35563044 PMCID: PMC9099445 DOI: 10.3390/ijms23094653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 04/19/2022] [Accepted: 04/19/2022] [Indexed: 02/07/2023] Open
Abstract
The damage and repair of DNA is a continuous process required to maintain genomic integrity. DNA double-strand breaks (DSBs) are the most lethal type of DNA damage and require timely repair by dedicated machinery. DSB repair is uniquely important to nondividing, post-mitotic cells of the central nervous system (CNS). These long-lived cells must rely on the intact genome for a lifetime while maintaining high metabolic activity. When these mechanisms fail, the loss of certain neuronal populations upset delicate neural networks required for higher cognition and disrupt vital motor functions. Mammalian cells engage with several different strategies to recognize and repair chromosomal DSBs based on the cellular context and cell cycle phase, including homologous recombination (HR)/homology-directed repair (HDR), microhomology-mediated end-joining (MMEJ), and the classic non-homologous end-joining (NHEJ). In addition to these repair pathways, a growing body of evidence has emphasized the importance of DNA damage response (DDR) signaling, and the involvement of heterogeneous nuclear ribonucleoprotein (hnRNP) family proteins in the repair of neuronal DSBs, many of which are linked to age-associated neurological disorders. In this review, we describe contemporary research characterizing the mechanistic roles of these non-canonical proteins in neuronal DSB repair, as well as their contributions to the etiopathogenesis of selected common neurological diseases.
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Affiliation(s)
- Vincent E. Provasek
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX 77030, USA; (V.E.P.); (V.H.M.)
- College of Medicine, Texas A&M University, College Station, TX 77843, USA
| | - Joy Mitra
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX 77030, USA; (V.E.P.); (V.H.M.)
- Correspondence: (J.M.); (M.L.H.)
| | - Vikas H. Malojirao
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX 77030, USA; (V.E.P.); (V.H.M.)
| | - Muralidhar L. Hegde
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX 77030, USA; (V.E.P.); (V.H.M.)
- College of Medicine, Texas A&M University, College Station, TX 77843, USA
- Department of Neurosciences, Weill Cornell Medical College, New York, NY 11021, USA
- Correspondence: (J.M.); (M.L.H.)
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19
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Nicolas G, Sévigny M, Lecoquierre F, Marguet F, Deschênes A, del Pelaez MC, Feuillette S, Audebrand A, Lecourtois M, Rousseau S, Richard AC, Cassinari K, Deramecourt V, Duyckaerts C, Boland A, Deleuze JF, Meyer V, Clarimon Echavarria J, Gelpi E, Akiyama H, Hasegawa M, Kawakami I, Wong TH, Van Rooij JGJ, Van Swieten JC, Campion D, Dutchak PA, Wallon D, Lavoie-Cardinal F, Laquerrière A, Rovelet-Lecrux A, Sephton CF. A postzygotic de novo NCDN mutation identified in a sporadic FTLD patient results in neurochondrin haploinsufficiency and altered FUS granule dynamics. Acta Neuropathol Commun 2022; 10:20. [PMID: 35151370 PMCID: PMC8841087 DOI: 10.1186/s40478-022-01314-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 01/18/2022] [Indexed: 12/19/2022] Open
Abstract
Frontotemporal dementia (FTD) is a heterogeneous clinical disorder characterized by progressive abnormalities in behavior, executive functions, personality, language and/or motricity. A neuropathological subtype of FTD, frontotemporal lobar degeneration (FTLD)-FET, is characterized by protein aggregates consisting of the RNA-binding protein fused in sarcoma (FUS). The cause of FTLD-FET is not well understood and there is a lack of genetic evidence to aid in the investigation of mechanisms of the disease. The goal of this study was to identify genetic variants contributing to FTLD-FET and to investigate their effects on FUS pathology. We performed whole-exome sequencing on a 50-year-old FTLD patient with ubiquitin and FUS-positive neuronal inclusions and unaffected parents, and identified a de novo postzygotic nonsense variant in the NCDN gene encoding Neurochondrin (NCDN), NM_014284.3:c.1206G > A, p.(Trp402*). The variant was associated with a ~ 31% reduction in full-length protein levels in the patient’s brain, suggesting that this mutation leads to NCDN haploinsufficiency. We examined the effects of NCDN haploinsufficiency on FUS and found that depleting primary cortical neurons of NCDN causes a reduction in the total number of FUS-positive cytoplasmic granules. Moreover, we found that these granules were significantly larger and more highly enriched with FUS. We then examined the effects of a loss of FUS function on NCDN in neurons and found that depleting cells of FUS leads to a decrease in NCDN protein and mRNA levels. Our study identifies the NCDN protein as a likely contributor of FTLD-FET pathophysiology. Moreover, we provide evidence for a negative feedback loop of toxicity between NCDN and FUS, where loss of NCDN alters FUS cytoplasmic dynamics, which in turn has an impact on NCDN expression.
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20
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TDP-43 pathology: from noxious assembly to therapeutic removal. Prog Neurobiol 2022; 211:102229. [DOI: 10.1016/j.pneurobio.2022.102229] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 12/08/2021] [Accepted: 01/26/2022] [Indexed: 02/08/2023]
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21
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Wang H, Kodavati M, Britz GW, Hegde ML. DNA Damage and Repair Deficiency in ALS/FTD-Associated Neurodegeneration: From Molecular Mechanisms to Therapeutic Implication. Front Mol Neurosci 2021; 14:784361. [PMID: 34975400 PMCID: PMC8716463 DOI: 10.3389/fnmol.2021.784361] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/25/2021] [Indexed: 02/03/2023] Open
Abstract
Emerging studies reveal that neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), are commonly linked to DNA damage accumulation and repair deficiency. Neurons are particularly vulnerable to DNA damage due to their high metabolic activity, relying primarily on oxidative phosphorylation, which leads to increased reactive oxygen species (ROS) generation and subsequent DNA damage. Efficient and timely repair of such damage is critical for guarding the integrity of genomic DNA and for cell survival. Several genes predominantly associated with RNA/DNA metabolism have been implicated in both ALS and FTD, suggesting that the two diseases share a common underlying pathology with varied clinical manifestations. Recent studies reveal that many of the gene products, including RNA/DNA binding proteins (RBPs) TDP-43 and FUS are involved in diverse DNA repair pathways. A key question in the etiology of the ALS/FTD spectrum of neurodegeneration is the mechanisms and pathways involved in genome instability caused by dysfunctions/mutations of those RBP genes and their consequences in the central nervous system. The understanding of such converging molecular mechanisms provides insights into the underlying etiology of the rapidly progressing neurodegeneration in ALS/FTD, while also revealing novel DNA repair target avenues for therapeutic development. In this review, we summarize the common mechanisms of neurodegeneration in ALS and FTD, with a particular emphasis on the DNA repair defects induced by ALS/FTD causative genes. We also highlight the consequences of DNA repair defects in ALS/FTD and the therapeutic potential of DNA damage repair-targeted amelioration of neurodegeneration.
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Affiliation(s)
- Haibo Wang
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
- Department of Neuroscience Research at Neurological Surgery, Weill Medical College, New York, NY, United States
| | - Manohar Kodavati
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
| | - Gavin W. Britz
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
- Department of Neuroscience Research at Neurological Surgery, Weill Medical College, New York, NY, United States
| | - Muralidhar L. Hegde
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, United States
- Department of Neuroscience Research at Neurological Surgery, Weill Medical College, New York, NY, United States
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22
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Ma X, Ying Y, Xie H, Liu X, Wang X, Li J. The Regulatory Role of RNA Metabolism Regulator TDP-43 in Human Cancer. Front Oncol 2021; 11:755096. [PMID: 34778070 PMCID: PMC8581290 DOI: 10.3389/fonc.2021.755096] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 10/08/2021] [Indexed: 12/26/2022] Open
Abstract
TAR-DNA-binding protein-43 (TDP-43) is a member of hnRNP family and acts as both RNA and DNA binding regulator, mediating RNA metabolism and transcription regulation in various diseases. Currently, emerging evidence gradually elucidates the crucial role of TDP-43 in human cancers like it is previously widely researched in neurodegeneration diseases. A series of RNA metabolism events, including mRNA alternative splicing, transport, stability, miRNA processing, and ncRNA regulation, are all confirmed to be closely involved in various carcinogenesis and tumor progressions, which are all partially regulated and interacted by TDP-43. Herein we conducted the first overall review about TDP-43 and cancers to systematically summarize the function and precise mechanism of TDP-43 in different human cancers. We hope it would provide basic knowledge and concepts for tumor target therapy and biomarker diagnosis in the future.
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Affiliation(s)
- Xueyou Ma
- Department of Urology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Cancer Center, Zhejiang University, Hangzhou, China
| | - Yufan Ying
- Department of Urology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Cancer Center, Zhejiang University, Hangzhou, China
| | - Haiyun Xie
- Department of Urology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Cancer Center, Zhejiang University, Hangzhou, China
| | - Xiaoyan Liu
- Department of Pathology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiao Wang
- Department of Urology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Cancer Center, Zhejiang University, Hangzhou, China
| | - Jiangfeng Li
- Department of Urology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Cancer Center, Zhejiang University, Hangzhou, China
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23
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Thompson AG, Oeckl P, Feneberg E, Bowser R, Otto M, Fischer R, Kessler B, Turner MR. Advancing mechanistic understanding and biomarker development in amyotrophic lateral sclerosis. Expert Rev Proteomics 2021; 18:977-994. [PMID: 34758687 DOI: 10.1080/14789450.2021.2004890] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Proteomic analysis has contributed significantly to the study of the neurodegenerative disease amyotrophic lateral sclerosis (ALS). It has helped to define the pathological change common to nearly all cases, namely intracellular aggregates of phosphorylated TDP-43, shifting the focus of pathogenesis in ALS toward RNA biology. Proteomics has also uniquely underpinned the delineation of disease mechanisms in model systems and has been central to recent advances in human ALS biomarker development. AREAS COVERED The contribution of proteomics to understanding the cellular pathological changes, disease mechanisms, and biomarker development in ALS are covered. EXPERT OPINION Proteomics has delivered unique insights into the pathogenesis of ALS and advanced the goal of objective measurements of disease activity to improve therapeutic trials. Further developments in sensitivity and quantification are expected, with application to the presymptomatic phase of human disease offering the hope of prevention strategies.
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Affiliation(s)
| | - Patrick Oeckl
- Department of Neurology, University of Ulm, Ulm, Germany.,German Center for Neurodegenerative Diseases (Dzne e.V.), Ulm, Germany
| | - Emily Feneberg
- Department of Neurology, Klinikum Rechts der Isar, Technical University Munich, Munich, Germany
| | - Robert Bowser
- Departments of Neurology and Translational Neuroscience, Barrow Neurological Institute, Phoenix, Arizona, USA
| | - Markus Otto
- Department of Neurology, University of Ulm, Ulm, Germany.,Department of Neurology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Roman Fischer
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Benedikt Kessler
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Martin R Turner
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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24
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Jia W, Kim SH, Scalf MA, Tonzi P, Millikin RJ, Guns WM, Liu L, Mastrocola AS, Smith LM, Huang TT, Tibbetts RS. Fused in sarcoma regulates DNA replication timing and kinetics. J Biol Chem 2021; 297:101049. [PMID: 34375640 PMCID: PMC8403768 DOI: 10.1016/j.jbc.2021.101049] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 07/12/2021] [Accepted: 08/03/2021] [Indexed: 11/17/2022] Open
Abstract
Fused in sarcoma (FUS) encodes an RNA-binding protein with diverse roles in transcriptional activation and RNA splicing. While oncogenic fusions of FUS and transcription factor DNA-binding domains are associated with soft tissue sarcomas, dominant mutations in FUS can cause amyotrophic lateral sclerosis. FUS has also been implicated in genome maintenance. However, the underlying mechanisms of its actions in genome stability are unknown. Here, we applied gene editing, functional reconstitution, and integrated proteomics and transcriptomics to illuminate roles for FUS in DNA replication and repair. Consistent with a supportive role in DNA double-strand break repair, FUS-deficient cells exhibited subtle alterations in the recruitment and retention of double-strand break-associated factors, including 53BP1 and BRCA1. FUS-/- cells also exhibited reduced proliferative potential that correlated with reduced speed of replication fork progression, diminished loading of prereplication complexes, enhanced micronucleus formation, and attenuated expression and splicing of S-phase-associated genes. Finally, FUS-deficient cells exhibited genome-wide alterations in DNA replication timing that were reversed upon re-expression of FUS complementary DNA. We also showed that FUS-dependent replication domains were enriched in transcriptionally active chromatin and that FUS was required for the timely replication of transcriptionally active DNA. These findings suggest that alterations in DNA replication kinetics and programming contribute to genome instability and functional defects in FUS-deficient cells.
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Affiliation(s)
- Weiyan Jia
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Sang Hwa Kim
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Mark A Scalf
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Peter Tonzi
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Health, New York, New York, USA
| | - Robert J Millikin
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - William M Guns
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Lu Liu
- Department of Biostatistics and Medical Informatics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Adam S Mastrocola
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Lloyd M Smith
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Tony T Huang
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Health, New York, New York, USA
| | - Randal S Tibbetts
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA.
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25
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Ahmed NS, Harrell LM, Wieland DR, Lay MA, Thompson VF, Schwartz JC. Fusion protein EWS-FLI1 is incorporated into a protein granule in cells. RNA (NEW YORK, N.Y.) 2021; 27:rna.078827.121. [PMID: 34035145 PMCID: PMC8284321 DOI: 10.1261/rna.078827.121] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 05/18/2021] [Indexed: 05/15/2023]
Abstract
Ewing sarcoma is driven by fusion proteins containing a low complexity (LC) domain that is intrinsically disordered and a powerful transcriptional regulator. The most common fusion protein found in Ewing sarcoma, EWS-FLI1, takes its LC domain from the RNA-binding protein EWSR1 (Ewing Sarcoma RNA-binding protein 1) and a DNA-binding domain from the transcription factor FLI1 (Friend Leukemia Virus Integration 1). EWS-FLI1 can bind RNA polymerase II (RNA Pol II) and self-assemble through its low-complexity (LC) domain. The ability of RNA-binding proteins like EWSR1 to self-assemble or phase separate in cells has raised questions about the contribution of this process to EWS-FLI1 activity. We examined EWSR1 and EWS-FLI1 activity in Ewing sarcoma cells by siRNA-mediated knockdown and RNA-seq analysis. More transcripts were affected by the EWSR1 knockdown than expected and these included many EWS-FLI1 regulated genes. We reevaluated physical interactions between EWS-FLI1, EWSR1, and RNA Pol II, and employed a cross-linking based strategy to investigate protein assemblies associated with the proteins. The LC domain of EWS-FLI1 was required for the assemblies observed to form in cells. These results offer new insights into a protein assembly that may enable EWS-FLI1 to bind its wide network of protein partners and contribute to regulation of gene expression in Ewing sarcoma.
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Affiliation(s)
- Nasiha S Ahmed
- Department of Molecular and Cellular Biology, The University of Arizona, Tucson, AZ 85719
| | - Lucas M Harrell
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ 85719
| | - Daniel R Wieland
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ 85719
| | - Michelle A Lay
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ 85719
| | - Valery F Thompson
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ 85719
| | - Jacob C Schwartz
- Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ 85719
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26
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Soldatov VO, Kukharsky MS, Belykh AE, Sobolev AM, Deykin AV. Retinal Damage in Amyotrophic Lateral Sclerosis: Underlying Mechanisms. Eye Brain 2021; 13:131-146. [PMID: 34012311 PMCID: PMC8128130 DOI: 10.2147/eb.s299423] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 03/04/2021] [Indexed: 01/04/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease resulting in a gradual loss of motor neuron function. Although ophthalmic complaints are not presently considered a classic symptom of ALS, retinal changes such as thinning, axonal degeneration and inclusion bodies have been found in many patients. Retinal abnormalities observed in postmortem human tissues and animal models are similar to spinal cord changes in ALS. These findings are not dramatically unexpected because retina shares an ontogenetic relationship with the brain, and many genes are associated both with neurodegeneration and retinal diseases. Experimental studies have demonstrated that ALS affects many “vulnerable points” of the retina. Aggregate deposition, impaired nuclear protein import, endoplasmic reticulum stress, glutamate excitotoxicity, vascular regression, and mitochondrial dysfunction are factors suspected as being the main cause of motor neuron damage in ALS. Herein, we show that all of these pathways can affect retinal cells in the same way as motor neurons. Furthermore, we suppose that understanding the patterns of neuro-ophthalmic interaction in ALS can help in the diagnosis and treatment of this disease.
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Affiliation(s)
- Vladislav O Soldatov
- Core Facility Centre, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia.,Department of Pharmacology and Clinical Pharmacology, Belgorod State National Research University, Belgorod, Russia
| | - Michail S Kukharsky
- Department of General and Cell Biology, Faculty of Medical Biology, Pirogov Russian National Research Medical University, Moscow, Russia.,Laboratory of Genetic Modelling of Neurodegenerative Processes, Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Russia
| | - Andrey E Belykh
- Department of Pathophysiology, Kursk State Medical University, Kursk, Russia
| | - Andrey M Sobolev
- Laboratory of Genetic Modelling of Neurodegenerative Processes, Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Russia
| | - Alexey V Deykin
- Department of Pharmacology and Clinical Pharmacology, Belgorod State National Research University, Belgorod, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
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27
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Ainslie A, Huiting W, Barazzuol L, Bergink S. Genome instability and loss of protein homeostasis: converging paths to neurodegeneration? Open Biol 2021; 11:200296. [PMID: 33878947 PMCID: PMC8059563 DOI: 10.1098/rsob.200296] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Genome instability and loss of protein homeostasis are hallmark events of age-related diseases that include neurodegeneration. Several neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis are characterized by protein aggregation, while an impaired DNA damage response (DDR) as in many genetic DNA repair disorders leads to pronounced neuropathological features. It remains unclear to what degree these cellular events interconnect with each other in the development of neurological diseases. This review highlights how the loss of protein homeostasis and genome instability influence one other. We will discuss studies that illustrate this connection. DNA damage contributes to many neurodegenerative diseases, as shown by an increased level of DNA damage in patients, possibly due to the effects of protein aggregates on chromatin, the sequestration of DNA repair proteins and novel putative DNA repair functions. Conversely, genome stability is also important for protein homeostasis. For example, gene copy number variations and the loss of key DDR components can lead to marked proteotoxic stress. An improved understanding of how protein homeostasis and genome stability are mechanistically connected is needed and promises to lead to the development of novel therapeutic interventions.
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Affiliation(s)
- Anna Ainslie
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands.,Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Wouter Huiting
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Lara Barazzuol
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands.,Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Steven Bergink
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
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28
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Abstract
Recent advancements in detection methods have made protein condensates, also called granules, a major area of study, but tools to characterize these assemblies need continued development to keep up with evolving paradigms. We have optimized a protocol to separate condensates from cells using chemical cross-linking followed by size-exclusion chromatography (SEC). After SEC fractionation, the samples can be characterized by a variety of approaches including enzyme-linked immunosorbent assay, dynamic light scattering, electron microscopy, and mass spectrometry. The protocol described here has been optimized for cultured mammalian cells and E. coli expressing recombinant proteins. Since the lysates are fractionated by size, this protocol can be modified to study other large protein assemblies, including the nuclear pore complex, and for other tissues or organisms. © 2021 Wiley Periodicals LLC. Basic Protocol 1: SEC separation of cross-linked mammalian cell lysates Alternate Protocol: Preparation of non-crosslinked mammalian cells Basic Protocol 2: SEC separation of E. coli lysate Support Protocol 1: Detecting protein of interest by ELISA Support Protocol 2: TCA precipitation of SEC fractions.
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Affiliation(s)
- Rachel A. Victor
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85745, USA
| | - Valery F. Thompson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85745, USA
| | - Jacob C. Schwartz
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85745, USA
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29
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Buratti E. Trends in Understanding the Pathological Roles of TDP-43 and FUS Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1281:243-267. [PMID: 33433879 DOI: 10.1007/978-3-030-51140-1_15] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Following the discovery of TDP-43 and FUS involvement in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar dementia (FTLD), the major challenge in the field has been to understand their physiological functions, both in normal and disease conditions. The hope is that this knowledge will improve our understanding of disease and lead to the development of effective therapeutic options. Initially, the focus has been directed at characterizing the role of these proteins in the control of RNA metabolism, because the main function of TDP-43 and FUS is to bind coding and noncoding RNAs to regulate their life cycle within cells. As a result, we now have an in-depth picture of the alterations that occur in RNA metabolism following their aggregation in various ALS/FTLD models and, to a somewhat lesser extent, in patients' brains. In parallel, progress has been made with regard to understanding how aggregation of these proteins occurs in neurons, how it can spread in different brain regions, and how these changes affect various metabolic cellular pathways to result in neuronal death. The aim of this chapter will be to provide a general overview of the trending topics in TDP-43 and FUS investigations and to highlight what might represent the most promising avenues of research in the years to come.
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Affiliation(s)
- Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.
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30
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Scarola M, Comisso E, Rosso M, Del Sal G, Schneider C, Schoeftner S, Benetti R. FUS-dependent loading of SUV39H1 to OCT4 pseudogene-lncRNA programs a silencing complex with OCT4 promoter specificity. Commun Biol 2020; 3:632. [PMID: 33128015 PMCID: PMC7603346 DOI: 10.1038/s42003-020-01355-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 10/01/2020] [Indexed: 11/16/2022] Open
Abstract
The resurrection of pseudogenes during evolution produced lncRNAs with new biological function. Here we show that pseudogene-evolution created an Oct4 pseudogene lncRNA that is able to direct epigenetic silencing of the parental Oct4 gene via a 2-step, lncRNA dependent mechanism. The murine Oct4 pseudogene 4 (mOct4P4) lncRNA recruits the RNA binding protein FUS to allow the binding of the SUV39H1 HMTase to a defined mOct4P4 lncRNA sequence element. The mOct4P4-FUS-SUV39H1 silencing complex holds target site specificity for the parental Oct4 promoter and interference with individual components results in loss of Oct4 silencing. SUV39H1 and FUS do not bind parental Oct4 mRNA, confirming the acquisition of a new biological function by the mOct4P4 lncRNA. Importantly, all features of mOct4P4 function are recapitulated by the human hOCT4P3 pseudogene lncRNA, indicating evolutionary conservation. Our data highlight the biological relevance of rapidly evolving lncRNAs that infiltrate into central epigenetic regulatory circuits in vertebrate cells.
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Affiliation(s)
- Michele Scarola
- Laboratorio Nazionale-Consorzio Interuniversitario per le Biotecnologie, Laboratorio Nazionale (LNCIB), Padriciano 99, 34149, Trieste, Italy
- Dipartimento di Area Medica (DAME), Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Elisa Comisso
- Laboratorio Nazionale-Consorzio Interuniversitario per le Biotecnologie, Laboratorio Nazionale (LNCIB), Padriciano 99, 34149, Trieste, Italy
- Dipartimento di Area Medica (DAME), Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Massimo Rosso
- Laboratorio Nazionale-Consorzio Interuniversitario per le Biotecnologie, Laboratorio Nazionale (LNCIB), Padriciano 99, 34149, Trieste, Italy
- Dipartimento di Science della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy
| | - Giannino Del Sal
- Laboratorio Nazionale-Consorzio Interuniversitario per le Biotecnologie, Laboratorio Nazionale (LNCIB), Padriciano 99, 34149, Trieste, Italy
- Dipartimento di Science della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy
| | - Claudio Schneider
- Laboratorio Nazionale-Consorzio Interuniversitario per le Biotecnologie, Laboratorio Nazionale (LNCIB), Padriciano 99, 34149, Trieste, Italy
- Dipartimento di Area Medica (DAME), Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy
| | - Stefan Schoeftner
- Laboratorio Nazionale-Consorzio Interuniversitario per le Biotecnologie, Laboratorio Nazionale (LNCIB), Padriciano 99, 34149, Trieste, Italy.
- Dipartimento di Science della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy.
| | - Roberta Benetti
- Laboratorio Nazionale-Consorzio Interuniversitario per le Biotecnologie, Laboratorio Nazionale (LNCIB), Padriciano 99, 34149, Trieste, Italy.
- Dipartimento di Area Medica (DAME), Università degli Studi di Udine, p.le Kolbe 4, 33100, Udine, Italy.
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31
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Suk TR, Rousseaux MWC. The role of TDP-43 mislocalization in amyotrophic lateral sclerosis. Mol Neurodegener 2020; 15:45. [PMID: 32799899 PMCID: PMC7429473 DOI: 10.1186/s13024-020-00397-1] [Citation(s) in RCA: 176] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/07/2020] [Indexed: 02/07/2023] Open
Abstract
Since its discovery as a primary component in cytoplasmic aggregates in post-mortem tissue of patients with Amyotrophic Lateral Sclerosis (ALS), TAR DNA Binding Protein 43 kDa (TDP-43) has remained a central focus to understand the disease. TDP-43 links both familial and sporadic forms of ALS as mutations are causative for disease and cytoplasmic aggregates are a hallmark of nearly all cases, regardless of TDP-43 mutational status. Research has focused on the formation and consequences of cytosolic protein aggregates as drivers of ALS pathology through both gain- and loss-of-function mechanisms. Not only does aggregation sequester the normal function of TDP-43, but these aggregates also actively block normal cellular processes inevitably leading to cellular demise in a short time span. Although there may be some benefit to therapeutically targeting TDP-43 aggregation, this step may be too late in disease development to have substantial therapeutic benefit. However, TDP-43 pathology appears to be tightly linked with its mislocalization from the nucleus to the cytoplasm, making it difficult to decouple the consequences of nuclear-to-cytoplasmic mislocalization from protein aggregation. Studies focusing on the effects of TDP-43 mislocalization have demonstrated both gain- and loss-of-function consequences including altered splicing regulation, over responsiveness to cellular stressors, increases in DNA damage, and transcriptome-wide changes. Additionally, mutations in TARDBP confer a baseline increase in cytoplasmic TDP-43 thus suggesting that small changes in the subcellular localization of TDP-43 could in fact drive early pathology. In this review, we bring forth the theme of protein mislocalization as a key mechanism underlying ALS, by highlighting the importance of maintaining subcellular proteostasis along with the gain- and loss-of-functional consequences when TDP-43 localization is dysregulated. Additional research, focusing on early events in TDP-43 pathogenesis (i.e. to the protein mislocalization stage) will provide insight into disease mechanisms, therapeutic targets, and novel biomarkers for ALS.
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Affiliation(s)
- Terry R. Suk
- University of Ottawa Brain and Mind Research Institute, Ottawa, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Maxime W. C. Rousseaux
- University of Ottawa Brain and Mind Research Institute, Ottawa, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
- Eric Poulin Center for Neuromuscular Diseases, Ottawa, Canada
- Ottawa Institute of Systems Biology, Ottawa, Canada
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