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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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Ingram HB, Fox AH. Unveiling the intricacies of paraspeckle formation and function. Curr Opin Cell Biol 2024; 90:102399. [PMID: 39033706 DOI: 10.1016/j.ceb.2024.102399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/19/2024] [Accepted: 06/25/2024] [Indexed: 07/23/2024]
Abstract
Paraspeckle nuclear bodies form when the NEAT1 long noncoding RNA is transcribed and bound by multiple RNA-binding proteins. First described 20 years ago, in recent years a growing appreciation of paraspeckle dynamics has led to new understandings, in both structure and function. Structurally, paraspeckles form via distinct physico-chemical domains arising from the composition of key proteins, recruited to different parts of NEAT1. These domains interact, creating a core-shell structured paraspeckle via microphase separation. Functionally, many environmental, chemical, and mechanical triggers can alter paraspeckle abundance, with important consequences depending on the cell type, developmental stage, and trigger identity. Underpinning these insights are new tools for paraspeckle research, including screening assays, proximity-based identification tools, and RNA processing modulators. A picture is emerging of paraspeckles as gene regulatory condensates in many healthy and disease settings. Critically, however, paraspeckle functional importance is generally most apparent when cells and organisms face external stressors.
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Affiliation(s)
- Hayley B Ingram
- School of Human Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Archa H Fox
- School of Human Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia.
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Shelkovnikova TA, Hautbergue GM. RNP granules in ALS and neurodegeneration: From multifunctional membraneless organelles to therapeutic opportunities. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2024; 176:455-479. [PMID: 38802180 DOI: 10.1016/bs.irn.2024.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) and related neurodegenerative diseases are characterised by dysfunction of a host of RNA-binding proteins (RBPs) and a severely disrupted RNA metabolism. Recently, RBP-harbouring phase-separated complexes, ribonucleoprotein (RNP) granules, have come into the limelight as "crucibles" of neuronal pathology in ALS. RNP granules are indispensable for the multitude of regulatory processes underlying cellular RNA metabolism and serve as critical organisers of cellular biochemistry. Neurons, highly specialised cells, heavily rely on RNP granules for efficient trafficking, signalling and stress responses. Multiple RNP granule components, primarily RBPs such as TDP-43 and FUS, are affected by ALS mutations. However, even in the absence of mutations, RBP proteinopathies represent pathophysiological hallmarks of ALS. Given the high local concentrations of RBPs and RNAs, their weakened or enhanced interactions within RNP granules disrupt their homeostasis. Thus, the physiological process of phase separation and RNP granule formation, vital for maintaining the high-functioning state of neuronal cells, becomes their Achilles heel. Here, we will review the recent literature on the causes and consequences of abnormal RNP granule functioning in ALS and related disorders. In particular, we will summarise the evidence for the network-level dysfunction of RNP granules in these conditions and discuss considerations for therapeutic interventions to target RBPs, RNP granules and their network as a whole.
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Affiliation(s)
- Tatyana A Shelkovnikova
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom; Neuroscience Institute, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom.
| | - Guillaume M Hautbergue
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield, United Kingdom; Neuroscience Institute, University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom; Healthy Lifespan Institute (HELSI), University of Sheffield, Firth Court, Western Bank, Sheffield, United Kingdom.
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Pal S, Nare Z, Rao VA, Smith BO, Morrison I, Fitzgerald EA, Scott A, Bingham MJ, Pesnot T. Accelerating BRPF1b hit identification with BioPhysical and Active Learning Screening (BioPALS). ChemMedChem 2024; 19:e202300590. [PMID: 38372199 DOI: 10.1002/cmdc.202300590] [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: 10/29/2023] [Revised: 01/25/2024] [Accepted: 02/12/2024] [Indexed: 02/20/2024]
Abstract
We report the development of BioPhysical and Active Learning Screening (BioPALS); a rapid and versatile hit identification protocol combining AI-powered virtual screening with a GCI-driven biophysical confirmation workflow. Its application to the BRPF1b bromodomain afforded a range of novel micromolar binders with favorable ADMET properties. In addition to the excellent in silico/in vitro confirmation rate demonstrated with BRPF1b, binding kinetics were determined, and binding topologies predicted for all hits. BioPALS is a lean, data-rich, and standardized approach to hit identification applicable to a wide range of biological targets.
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Affiliation(s)
- Sandeep Pal
- Concept Life Sciences, Frith Knoll Road, Chapel-en-le-Frith, SK23 0PG, High Peak, UK
| | - Zandile Nare
- Concept Life Sciences, Frith Knoll Road, Chapel-en-le-Frith, SK23 0PG, High Peak, UK
| | - Vincenzo A Rao
- Concept Life Sciences, Frith Knoll Road, Chapel-en-le-Frith, SK23 0PG, High Peak, UK
| | - Brian O Smith
- University of Glasgow, School of Molecular Biosciences, College of Medical Veterinary and Life Sciences, G12 8QQ, Glasgow, UK
| | - Ian Morrison
- Concept Life Sciences, Frith Knoll Road, Chapel-en-le-Frith, SK23 0PG, High Peak, UK
| | | | - Andrew Scott
- Concept Life Sciences, Frith Knoll Road, Chapel-en-le-Frith, SK23 0PG, High Peak, UK
| | - Matilda J Bingham
- Concept Life Sciences, Frith Knoll Road, Chapel-en-le-Frith, SK23 0PG, High Peak, UK
| | - Thomas Pesnot
- Concept Life Sciences, Frith Knoll Road, Chapel-en-le-Frith, SK23 0PG, High Peak, UK
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Shivakumar KM, Mahendran G, Brown JA. Locked Nucleic Acid Oligonucleotides Facilitate RNA•LNA-RNA Triple-Helix Formation and Reduce MALAT1 Levels. Int J Mol Sci 2024; 25:1630. [PMID: 38338910 PMCID: PMC10855403 DOI: 10.3390/ijms25031630] [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: 12/01/2023] [Revised: 01/25/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and multiple endocrine neoplasia-β (MENβ) are two long noncoding RNAs upregulated in multiple cancers, marking these RNAs as therapeutic targets. While traditional small-molecule and antisense-based approaches are effective, we report a locked nucleic acid (LNA)-based approach that targets the MALAT1 and MENβ triple helices, structures comprised of a U-rich internal stem-loop and an A-rich tract. Two LNA oligonucleotides resembling the A-rich tract (i.e., A9GCA4) were examined: an LNA (L15) and a phosphorothioate LNA (PS-L15). L15 binds tighter than PS-L15 to the MALAT1 and MENβ stem loops, although both L15 and PS-L15 enable RNA•LNA-RNA triple-helix formation. Based on UV thermal denaturation assays, both LNAs selectively stabilize the Hoogsteen interface by 5-13 °C more than the Watson-Crick interface. Furthermore, we show that L15 and PS-L15 displace the A-rich tract from the MALAT1 and MENβ stem loop and methyltransferase-like protein 16 (METTL16) from the METTL16-MALAT1 triple-helix complex. Human colorectal carcinoma (HCT116) cells transfected with LNAs have 2-fold less MALAT1 and MENβ. This LNA-based approach represents a potential therapeutic strategy for the dual targeting of MALAT1 and MENβ.
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Affiliation(s)
| | | | - Jessica A. Brown
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; (K.M.S.); (G.M.)
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Obuse C, Hirose T. Functional domains of nuclear long noncoding RNAs: Insights into gene regulation and intracellular architecture. Curr Opin Cell Biol 2023; 85:102250. [PMID: 37806294 DOI: 10.1016/j.ceb.2023.102250] [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: 05/17/2023] [Revised: 08/12/2023] [Accepted: 09/07/2023] [Indexed: 10/10/2023]
Abstract
Recent functional research on long noncoding RNAs (lncRNAs) has revealed their significant regulatory roles in gene expression and intracellular architecture. Well-characterized examples of such lncRNAs include Xist and NEAT1_2, which play critical roles in heterochromatin formation of inactive X-chromosomes and paraspeckle assembly, in mammalian cells. Both lncRNAs possess modular domain structures with multiple functionally distinct domains that serve as platforms for specific RNA-binding proteins (RBPs), which dictate the function of each lncRNA. Some of these RBPs bind characteristic RNA structures, which can be targeted by small chemical compounds that modulate lncRNA function by perturbing the interaction of RBPs with the RNA structures. Therefore, RNA structures hidden in lncRNAs represent a novel and potent type of therapeutic target.
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Affiliation(s)
- Chikashi Obuse
- Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan; Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita 565-0871, Japan
| | - Tetsuro Hirose
- Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan; Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan; Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita 565-0871, Japan.
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