1
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Ho PC, Hsieh TC, Tsai KJ. TDP-43 proteinopathy in frontotemporal lobar degeneration and amyotrophic lateral sclerosis: From pathomechanisms to therapeutic strategies. Ageing Res Rev 2024; 100:102441. [PMID: 39069095 DOI: 10.1016/j.arr.2024.102441] [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: 05/31/2024] [Revised: 07/12/2024] [Accepted: 07/24/2024] [Indexed: 07/30/2024]
Abstract
Proteostasis failure is a common pathological characteristic in neurodegenerative diseases. Revitalizing clearance systems could effectively mitigate these diseases. The transactivation response (TAR) DNA-binding protein 43 (TDP-43) plays a critical role as an RNA/DNA-binding protein in RNA metabolism and synaptic function. Accumulation of TDP-43 aggregates in the central nervous system is a hallmark of frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Autophagy, a major and highly conserved degradation pathway, holds the potential for degrading aggregated TDP-43 and alleviating FTLD/ALS. This review explores the causes of TDP-43 aggregation, FTLD/ALS-related genes, key autophagy factors, and autophagy-based therapeutic strategies targeting TDP-43 proteinopathy. Understanding the underlying pathological mechanisms of TDP-43 proteinopathy can facilitate therapeutic interventions.
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Affiliation(s)
- Pei-Chuan Ho
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Tsung-Chi Hsieh
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Kuen-Jer Tsai
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Research Center of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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2
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Huang WP, Ellis BCS, Hodgson RE, Sanchez Avila A, Kumar V, Rayment J, Moll T, Shelkovnikova TA. Stress-induced TDP-43 nuclear condensation causes splicing loss of function and STMN2 depletion. Cell Rep 2024; 43:114421. [PMID: 38941189 DOI: 10.1016/j.celrep.2024.114421] [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: 01/10/2024] [Revised: 04/04/2024] [Accepted: 06/14/2024] [Indexed: 06/30/2024] Open
Abstract
TDP-43 protein is dysregulated in several neurodegenerative diseases, which often have a multifactorial nature and may have extrinsic stressors as a "second hit." TDP-43 undergoes reversible nuclear condensation in stressed cells including neurons. Here, we demonstrate that stress-inducible nuclear TDP-43 condensates are RNA-depleted, non-liquid assemblies distinct from the known nuclear bodies. Their formation requires TDP-43 oligomerization and ATP and is inhibited by RNA. Using a confocal nanoscanning assay, we find that amyotrophic lateral sclerosis (ALS)-linked mutations alter stress-induced TDP-43 condensation by changing its affinity to liquid-like ribonucleoprotein assemblies. Stress-induced nuclear condensation transiently inactivates TDP-43, leading to loss of interaction with its protein binding partners and loss of function in splicing. Splicing changes are especially prominent and persisting for STMN2 RNA, and STMN2 protein becomes rapidly depleted early during stress. Our results point to early pathological changes to TDP-43 in the nucleus and support therapeutic modulation of stress response in ALS.
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Affiliation(s)
- Wan-Ping Huang
- Sheffield Institute for Translational Neuroscience and Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Brittany C S Ellis
- Sheffield Institute for Translational Neuroscience and Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Rachel E Hodgson
- Sheffield Institute for Translational Neuroscience and Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Anna Sanchez Avila
- Sheffield Institute for Translational Neuroscience and Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Vedanth Kumar
- Sheffield Institute for Translational Neuroscience and Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Jessica Rayment
- Sheffield Institute for Translational Neuroscience and Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Tobias Moll
- Sheffield Institute for Translational Neuroscience and Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Tatyana A Shelkovnikova
- Sheffield Institute for Translational Neuroscience and Neuroscience Institute, University of Sheffield, Sheffield, UK.
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3
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Lang R, Hodgson RE, Shelkovnikova TA. TDP-43 in nuclear condensates: where, how, and why. Biochem Soc Trans 2024:BST20231447. [PMID: 38958608 DOI: 10.1042/bst20231447] [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: 04/22/2024] [Revised: 06/12/2024] [Accepted: 06/17/2024] [Indexed: 07/04/2024]
Abstract
TDP-43 is an abundant and ubiquitously expressed nuclear protein that becomes dysfunctional in a spectrum of neurodegenerative diseases. TDP-43's ability to phase separate and form/enter biomolecular condensates of varying size and composition is critical for its functionality. Despite the high density of phase-separated assemblies in the nucleus and the nuclear abundance of TDP-43, our understanding of the condensate-TDP-43 relationship in this cellular compartment is only emerging. Recent studies have also suggested that misregulation of nuclear TDP-43 condensation is an early event in the neurodegenerative disease amyotrophic lateral sclerosis. This review aims to draw attention to the nuclear facet of functional and aberrant TDP-43 condensation. We will summarise the current knowledge on how TDP-43 containing nuclear condensates form and function and how their homeostasis is affected in disease.
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Affiliation(s)
- Ruaridh Lang
- Sheffield Institute for Translational Neuroscience (SITraN) and Neuroscience Institute, University of Sheffield, Sheffield, U.K
| | - Rachel E Hodgson
- Sheffield Institute for Translational Neuroscience (SITraN) and Neuroscience Institute, University of Sheffield, Sheffield, U.K
| | - Tatyana A Shelkovnikova
- Sheffield Institute for Translational Neuroscience (SITraN) and Neuroscience Institute, University of Sheffield, Sheffield, U.K
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4
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Francisco-Velilla R, Abellan S, Embarc-Buh A, Martinez-Salas E. Oligomerization regulates the interaction of Gemin5 with members of the SMN complex and the translation machinery. Cell Death Discov 2024; 10:306. [PMID: 38942768 PMCID: PMC11213948 DOI: 10.1038/s41420-024-02057-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 05/29/2024] [Accepted: 06/04/2024] [Indexed: 06/30/2024] Open
Abstract
RNA-binding proteins are multifunctional molecules impacting on multiple steps of gene regulation. Gemin5 was initially identified as a member of the survival of motor neurons (SMN) complex. The protein is organized in structural and functional domains, including a WD40 repeats domain at the N-terminal region, a tetratricopeptide repeat (TPR) dimerization module at the central region, and a non-canonical RNA-binding site at the C-terminal end. The TPR module allows the recruitment of the endogenous Gemin5 protein in living cells and the assembly of a dimer in vitro. However, the biological relevance of Gemin5 oligomerization is not known. Here we interrogated the Gemin5 interactome focusing on oligomerization-dependent or independent regions. We show that the interactors associated with oligomerization-proficient domains were primarily annotated to ribosome, splicing, translation regulation, SMN complex, and RNA stability. The presence of distinct Gemin5 protein regions in polysomes highlighted differences in translation regulation based on their oligomerization capacity. Furthermore, the association with native ribosomes and negative regulation of translation was strictly dependent on both the WD40 repeats domain and the TPR dimerization moiety, while binding with the majority of the interacting proteins, including SMN, Gemin2, and Gemin4, was determined by the dimerization module. The loss of oligomerization did not perturb the predominant cytoplasmic localization of Gemin5, reinforcing the cytoplasmic functions of this essential protein. Our work highlights a distinctive role of the Gemin5 domains for its functions in the interaction with members of the SMN complex, ribosome association, and RBP interactome.
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Affiliation(s)
| | - Salvador Abellan
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049, Madrid, Spain
| | - Azman Embarc-Buh
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049, Madrid, Spain
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5
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Scherer NM, Maurel C, Graus M, McAlary L, Richter G, Radford RW, Hogan A, Don E, Lee A, Yerbury J, Francois M, Chung R, Morsch M. RNA-binding properties orchestrate TDP-43 homeostasis through condensate formation in vivo. Nucleic Acids Res 2024; 52:5301-5319. [PMID: 38381071 PMCID: PMC11109982 DOI: 10.1093/nar/gkae112] [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: 06/23/2023] [Revised: 01/12/2024] [Accepted: 02/06/2024] [Indexed: 02/22/2024] Open
Abstract
Insoluble cytoplasmic aggregate formation of the RNA-binding protein TDP-43 is a major hallmark of neurodegenerative diseases including Amyotrophic Lateral Sclerosis. TDP-43 localizes predominantly in the nucleus, arranging itself into dynamic condensates through liquid-liquid phase separation (LLPS). Mutations and post-translational modifications can alter the condensation properties of TDP-43, contributing to the transition of liquid-like biomolecular condensates into solid-like aggregates. However, to date it has been a challenge to study the dynamics of this process in vivo. We demonstrate through live imaging that human TDP-43 undergoes nuclear condensation in spinal motor neurons in a living animal. RNA-binding deficiencies as well as post-translational modifications can lead to aberrant condensation and altered TDP-43 compartmentalization. Single-molecule tracking revealed an altered mobility profile for RNA-binding deficient TDP-43. Overall, these results provide a critically needed in vivo characterization of TDP-43 condensation, demonstrate phase separation as an important regulatory mechanism of TDP-43 accessibility, and identify a molecular mechanism of how functional TDP-43 can be regulated.
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Affiliation(s)
- Natalie M Scherer
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Cindy Maurel
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Matthew S Graus
- The David Richmond Laboratory for Cardio-Vascular Development: gene regulation and editing, Centenary Institute, The University of Sydney, School of Medical Sciences, Sydney, NSW 2006, Australia
- Genome Imaging Centre, Centenary Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Luke McAlary
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Grant Richter
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Rowan A W Radford
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Alison Hogan
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Emily K Don
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Albert Lee
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Justin Yerbury
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Mathias Francois
- The David Richmond Laboratory for Cardio-Vascular Development: gene regulation and editing, Centenary Institute, The University of Sydney, School of Medical Sciences, Sydney, NSW 2006, Australia
- Genome Imaging Centre, Centenary Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Roger S Chung
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Marco Morsch
- Faculty of Medicine, Health & Human Sciences, Macquarie Medical School, MND Research Centre, Macquarie University, Sydney, NSW 2109, Australia
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6
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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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7
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Hruska-Plochan M, Wiersma VI, Betz KM, Mallona I, Ronchi S, Maniecka Z, Hock EM, Tantardini E, Laferriere F, Sahadevan S, Hoop V, Delvendahl I, Pérez-Berlanga M, Gatta B, Panatta M, van der Bourg A, Bohaciakova D, Sharma P, De Vos L, Frontzek K, Aguzzi A, Lashley T, Robinson MD, Karayannis T, Mueller M, Hierlemann A, Polymenidou M. A model of human neural networks reveals NPTX2 pathology in ALS and FTLD. Nature 2024; 626:1073-1083. [PMID: 38355792 PMCID: PMC10901740 DOI: 10.1038/s41586-024-07042-7] [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: 09/28/2021] [Accepted: 01/08/2024] [Indexed: 02/16/2024]
Abstract
Human cellular models of neurodegeneration require reproducibility and longevity, which is necessary for simulating age-dependent diseases. Such systems are particularly needed for TDP-43 proteinopathies1, which involve human-specific mechanisms2-5 that cannot be directly studied in animal models. Here, to explore the emergence and consequences of TDP-43 pathologies, we generated induced pluripotent stem cell-derived, colony morphology neural stem cells (iCoMoNSCs) via manual selection of neural precursors6. Single-cell transcriptomics and comparison to independent neural stem cells7 showed that iCoMoNSCs are uniquely homogenous and self-renewing. Differentiated iCoMoNSCs formed a self-organized multicellular system consisting of synaptically connected and electrophysiologically active neurons, which matured into long-lived functional networks (which we designate iNets). Neuronal and glial maturation in iNets was similar to that of cortical organoids8. Overexpression of wild-type TDP-43 in a minority of neurons within iNets led to progressive fragmentation and aggregation of the protein, resulting in a partial loss of function and neurotoxicity. Single-cell transcriptomics revealed a novel set of misregulated RNA targets in TDP-43-overexpressing neurons and in patients with TDP-43 proteinopathies exhibiting a loss of nuclear TDP-43. The strongest misregulated target encoded the synaptic protein NPTX2, the levels of which are controlled by TDP-43 binding on its 3' untranslated region. When NPTX2 was overexpressed in iNets, it exhibited neurotoxicity, whereas correcting NPTX2 misregulation partially rescued neurons from TDP-43-induced neurodegeneration. Notably, NPTX2 was consistently misaccumulated in neurons from patients with amyotrophic lateral sclerosis and frontotemporal lobar degeneration with TDP-43 pathology. Our work directly links TDP-43 misregulation and NPTX2 accumulation, thereby revealing a TDP-43-dependent pathway of neurotoxicity.
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Affiliation(s)
| | - Vera I Wiersma
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Katharina M Betz
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- SIB Swiss Institute of Bioinformatics, University of Zurich, Zurich, Switzerland
| | - Izaskun Mallona
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- SIB Swiss Institute of Bioinformatics, University of Zurich, Zurich, Switzerland
| | - Silvia Ronchi
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
- MaxWell Biosystems AG, Zurich, Switzerland
| | - Zuzanna Maniecka
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Eva-Maria Hock
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Elena Tantardini
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Florent Laferriere
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Sonu Sahadevan
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Vanessa Hoop
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Igor Delvendahl
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | | | - Beatrice Gatta
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Martina Panatta
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | | | - Dasa Bohaciakova
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University Brno, Brno, Czech Republic
| | - Puneet Sharma
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
- NCCR RNA and Disease Technology Platform, Bern, Switzerland
| | - Laura De Vos
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
| | - Karl Frontzek
- Institute of Neuropathology, University of Zurich, Zurich, Switzerland
| | - Adriano Aguzzi
- Institute of Neuropathology, University of Zurich, Zurich, Switzerland
| | - Tammaryn Lashley
- Queen Square Brain Bank for Neurological diseases, Department of Movement Disorders, UCL Institute of Neurology, London, UK
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK
| | - Mark D Robinson
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- SIB Swiss Institute of Bioinformatics, University of Zurich, Zurich, Switzerland
| | | | - Martin Mueller
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Andreas Hierlemann
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
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8
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Dos Passos PM, Hemamali EH, Mamede LD, Hayes LR, Ayala YM. RNA-mediated ribonucleoprotein assembly controls TDP-43 nuclear retention. PLoS Biol 2024; 22:e3002527. [PMID: 38422113 DOI: 10.1371/journal.pbio.3002527] [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: 08/22/2023] [Revised: 03/12/2024] [Accepted: 01/29/2024] [Indexed: 03/02/2024] Open
Abstract
TDP-43 is an essential RNA-binding protein strongly implicated in the pathogenesis of neurodegenerative disorders characterized by cytoplasmic aggregates and loss of nuclear TDP-43. The protein shuttles between nucleus and cytoplasm, yet maintaining predominantly nuclear TDP-43 localization is important for TDP-43 function and for inhibiting cytoplasmic aggregation. We previously demonstrated that specific RNA binding mediates TDP-43 self-assembly and biomolecular condensation, requiring multivalent interactions via N- and C-terminal domains. Here, we show that these complexes play a key role in TDP-43 nuclear retention. TDP-43 forms macromolecular complexes with a wide range of size distribution in cells and we find that defects in RNA binding or inter-domain interactions, including phase separation, impair the assembly of the largest species. Our findings suggest that recruitment into these macromolecular complexes prevents cytoplasmic egress of TDP-43 in a size-dependent manner. Our observations uncover fundamental mechanisms controlling TDP-43 cellular homeostasis, whereby regulation of RNA-mediated self-assembly modulates TDP-43 nucleocytoplasmic distribution. Moreover, these findings highlight pathways that may be implicated in TDP-43 proteinopathies and identify potential therapeutic targets.
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Affiliation(s)
- Patricia M Dos Passos
- Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - Erandika H Hemamali
- Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - Lohany D Mamede
- Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - Lindsey R Hayes
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Yuna M Ayala
- Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
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9
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Gkekas I, Vagiona AC, Pechlivanis N, Kastrinaki G, Pliatsika K, Iben S, Xanthopoulos K, Psomopoulos FE, Andrade-Navarro MA, Petrakis S. Intranuclear inclusions of polyQ-expanded ATXN1 sequester RNA molecules. Front Mol Neurosci 2023; 16:1280546. [PMID: 38125008 PMCID: PMC10730666 DOI: 10.3389/fnmol.2023.1280546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 11/16/2023] [Indexed: 12/23/2023] Open
Abstract
Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant neurodegenerative disease caused by a trinucleotide (CAG) repeat expansion in the ATXN1 gene. It is characterized by the presence of polyglutamine (polyQ) intranuclear inclusion bodies (IIBs) within affected neurons. In order to investigate the impact of polyQ IIBs in SCA1 pathogenesis, we generated a novel protein aggregation model by inducible overexpression of the mutant ATXN1(Q82) isoform in human neuroblastoma SH-SY5Y cells. Moreover, we developed a simple and reproducible protocol for the efficient isolation of insoluble IIBs. Biophysical characterization showed that polyQ IIBs are enriched in RNA molecules which were further identified by next-generation sequencing. Finally, a protein interaction network analysis indicated that sequestration of essential RNA transcripts within ATXN1(Q82) IIBs may affect the ribosome resulting in error-prone protein synthesis and global proteome instability. These findings provide novel insights into the molecular pathogenesis of SCA1, highlighting the role of polyQ IIBs and their impact on critical cellular processes.
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Affiliation(s)
- Ioannis Gkekas
- Centre for Research and Technology Hellas, Institute of Applied Biosciences, Thessaloniki, Greece
- Laboratory of Pharmacology, School of Pharmacy, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | | | - Nikolaos Pechlivanis
- Centre for Research and Technology Hellas, Institute of Applied Biosciences, Thessaloniki, Greece
| | - Georgia Kastrinaki
- Aerosol and Particle Technology Laboratory, Centre for Research and Technology Hellas, Chemical Process and Energy Resources Institute, Thessaloniki, Greece
| | - Katerina Pliatsika
- Centre for Research and Technology Hellas, Institute of Applied Biosciences, Thessaloniki, Greece
- Laboratory of Pharmacology, School of Pharmacy, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Sebastian Iben
- Department of Dermatology and Allergic Diseases, University of Ulm, Ulm, Germany
| | - Konstantinos Xanthopoulos
- Centre for Research and Technology Hellas, Institute of Applied Biosciences, Thessaloniki, Greece
- Laboratory of Pharmacology, School of Pharmacy, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Fotis E. Psomopoulos
- Centre for Research and Technology Hellas, Institute of Applied Biosciences, Thessaloniki, Greece
| | | | - Spyros Petrakis
- Centre for Research and Technology Hellas, Institute of Applied Biosciences, Thessaloniki, Greece
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10
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Song J. Molecular mechanisms of phase separation and amyloidosis of ALS/FTD-linked FUS and TDP-43. Aging Dis 2023:AD.2023.1118. [PMID: 38029395 DOI: 10.14336/ad.2023.1118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [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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11
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Linsenmeier M, Faltova L, Morelli C, Capasso Palmiero U, Seiffert C, Küffner AM, Pinotsi D, Zhou J, Mezzenga R, Arosio P. The interface of condensates of the hnRNPA1 low-complexity domain promotes formation of amyloid fibrils. Nat Chem 2023; 15:1340-1349. [PMID: 37749234 PMCID: PMC10533390 DOI: 10.1038/s41557-023-01289-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 07/05/2023] [Indexed: 09/27/2023]
Abstract
The maturation of liquid-like protein condensates into amyloid fibrils has been associated with several neurodegenerative diseases. However, the molecular mechanisms underlying this liquid-to-solid transition have remained largely unclear. Here we analyse the amyloid formation mediated by condensation of the low-complexity domain of hnRNPA1, a protein involved in amyotrophic lateral sclerosis. We show that phase separation and fibrillization are connected but distinct processes that are modulated by different regions of the protein sequence. By monitoring the spatial and temporal evolution of amyloid formation we demonstrate that the formation of fibrils does not occur homogeneously inside the droplets but is promoted at the interface of the condensates. We further show that coating the interface of the droplets with surfactant molecules inhibits fibril formation. Our results reveal that the interface of biomolecular condensates of hnRNPA1 promotes fibril formation, therefore suggesting interfaces as a potential novel therapeutic target against the formation of aberrant amyloids mediated by condensation.
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Affiliation(s)
- Miriam Linsenmeier
- Department of Chemistry and Applied Sciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, Switzerland
| | - Lenka Faltova
- Department of Chemistry and Applied Sciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, Switzerland
| | - Chiara Morelli
- Department of Chemistry and Applied Sciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, Switzerland
| | - Umberto Capasso Palmiero
- Department of Chemistry and Applied Sciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, Switzerland
| | - Charlotte Seiffert
- Department of Chemistry and Applied Sciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, Switzerland
| | - Andreas M Küffner
- Department of Chemistry and Applied Sciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, Switzerland
| | - Dorothea Pinotsi
- Scientific Center for Optical and Electron Microscopy, ETH Zurich, Zurich, Switzerland
| | - Jiangtao Zhou
- Department for Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Raffaele Mezzenga
- Department for Health Sciences and Technology, Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Paolo Arosio
- Department of Chemistry and Applied Sciences, Institute for Chemical and Bioengineering, ETH Zurich, Zurich, Switzerland.
- Bringing Materials to Life Initiative, ETH Zurich, Zurich, Switzerland.
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Dos Passos PM, Hemamali EH, Mamede LD, Hayes LR, Ayala YM. RNA-mediated ribonucleoprotein assembly controls TDP-43 nuclear retention. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.06.552215. [PMID: 37609278 PMCID: PMC10441353 DOI: 10.1101/2023.08.06.552215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
TDP-43 is an essential RNA-binding protein strongly implicated in the pathogenesis of neurodegenerative disorders characterized by cytoplasmic aggregates and loss of nuclear TDP-43. The protein shuttles between nucleus and cytoplasm, yet maintaining predominantly nuclear TDP-43 localization is important for TDP-43 function and for inhibiting cytoplasmic aggregation. We previously demonstrated that specific RNA binding mediates TDP-43 self-assembly and biomolecular condensation, requiring multivalent interactions via N- and C-terminal domains. Here, we show that these complexes play a key role in TDP-43 nuclear retention. TDP-43 forms macromolecular complexes with a wide range of size distribution in cells and we find that defects in RNA binding or inter-domain interactions, including phase separation, impair the assembly of the largest species. Our findings suggest that recruitment into these macromolecular complexes prevents cytoplasmic egress of TDP-43 in a size-dependent manner. Our observations uncover fundamental mechanisms controlling TDP-43 cellular homeostasis, whereby regulation of RNA-mediated self-assembly modulates TDP-43 nucleocytoplasmic distribution. Moreover, these findings highlight pathways that may be implicated in TDP-43 proteinopathies and identify potential therapeutic targets.
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