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Naskar A, Nayak A, Salaikumaran MR, Vishal SS, Gopal PP. Phase separation and pathologic transitions of RNP condensates in neurons: implications for amyotrophic lateral sclerosis, frontotemporal dementia and other neurodegenerative disorders. Front Mol Neurosci 2023; 16:1242925. [PMID: 37720552 PMCID: PMC10502346 DOI: 10.3389/fnmol.2023.1242925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/21/2023] [Indexed: 09/19/2023] Open
Abstract
Liquid-liquid phase separation results in the formation of dynamic biomolecular condensates, also known as membrane-less organelles, that allow for the assembly of functional compartments and higher order structures within cells. Multivalent, reversible interactions between RNA-binding proteins (RBPs), including FUS, TDP-43, and hnRNPA1, and/or RNA (e.g., RBP-RBP, RBP-RNA, RNA-RNA), result in the formation of ribonucleoprotein (RNP) condensates, which are critical for RNA processing, mRNA transport, stability, stress granule assembly, and translation. Stress granules, neuronal transport granules, and processing bodies are examples of cytoplasmic RNP condensates, while the nucleolus and Cajal bodies are representative nuclear RNP condensates. In neurons, RNP condensates promote long-range mRNA transport and local translation in the dendrites and axon, and are essential for spatiotemporal regulation of gene expression, axonal integrity and synaptic function. Mutations of RBPs and/or pathologic mislocalization and aggregation of RBPs are hallmarks of several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and Alzheimer's disease. ALS/FTD-linked mutations of RBPs alter the strength and reversibility of multivalent interactions with other RBPs and RNAs, resulting in aberrant phase transitions. These aberrant RNP condensates have detrimental functional consequences on mRNA stability, localization, and translation, and ultimately lead to compromised axonal integrity and synaptic function in disease. Pathogenic protein aggregation is dependent on various factors, and aberrant dynamically arrested RNP condensates may serve as an initial nucleation step for pathologic aggregate formation. Recent studies have focused on identifying mechanisms by which neurons resolve phase transitioned condensates to prevent the formation of pathogenic inclusions/aggregates. The present review focuses on the phase separation of neurodegenerative disease-linked RBPs, physiological functions of RNP condensates, and the pathologic role of aberrant phase transitions in neurodegenerative disease, particularly ALS/FTD. We also examine cellular mechanisms that contribute to the resolution of aberrant condensates in neurons, and potential therapeutic approaches to resolve aberrantly phase transitioned condensates at a molecular level.
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Affiliation(s)
- Aditi Naskar
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
| | - Asima Nayak
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
| | | | - Sonali S. Vishal
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
| | - Pallavi P. Gopal
- Department of Pathology, Yale School of Medicine, New Haven, CT, United States
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale School of Medicine, New Haven, CT, United States
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5
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Horio T, Ishikura Y, Ohashi R, Shiina N. Regulation of RNG105/caprin1 dynamics by pathogenic cytoplasmic FUS and TDP-43 in neuronal RNA granules modulates synaptic loss. Heliyon 2023; 9:e17065. [PMID: 37484309 PMCID: PMC10361247 DOI: 10.1016/j.heliyon.2023.e17065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 05/25/2023] [Accepted: 06/06/2023] [Indexed: 07/25/2023] Open
Abstract
In neurodegenerative diseases, the condensation of FUS and TDP-43 with RNA granules in neurons is linked to pathology, including synaptic disorders. However, the effects of FUS and TDP-43 on RNA granule factors remain unclear. Here, using primary cultured neurons from the mouse cerebral cortex, we show that excess cytoplasmic FUS and TDP-43 accumulated in dendritic RNA granules, where they increased the dynamics of a scaffold protein RNG105/caprin1 and dissociated it from the granules. This coincided with reduced levels of mRNA and translation around the granules and synaptic loss in dendrites. These defects were suppressed by non-dissociable RNG105, suggesting that RNG105 dissociation mediated the defects. In contrast to the model where FUS and TDP-43 co-aggregate with RNA granule factors to repress their activity, our findings provide a novel pathogenic mechanism whereby FUS and TDP-43 dissociate RNA scaffold proteins from RNA granules which are required for local translation that regulates synapse formation.
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Affiliation(s)
- Tomoyo Horio
- Laboratory of Neuronal Cell Biology, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan
- Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8585, Japan
| | - Yui Ishikura
- Laboratory of Neuronal Cell Biology, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan
- Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8585, Japan
| | - Rie Ohashi
- Laboratory of Neuronal Cell Biology, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan
- Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8585, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan
- Life Science Research Center, University of Toyama, Toyama, Toyama 930-0194, Japan
| | - Nobuyuki Shiina
- Laboratory of Neuronal Cell Biology, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan
- Department of Basic Biology, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8585, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan
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8
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Bremer A, Posey AE, Borgia MB, Borcherds WM, Farag M, Pappu RV, Mittag T. Quantifying Coexistence Concentrations in Multi-Component Phase-Separating Systems Using Analytical HPLC. Biomolecules 2022; 12:biom12101480. [PMID: 36291688 PMCID: PMC9599810 DOI: 10.3390/biom12101480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 11/28/2022] Open
Abstract
Over the last decade, evidence has accumulated to suggest that numerous instances of cellular compartmentalization can be explained by the phenomenon of phase separation. This is a process by which a macromolecular solution separates spontaneously into dense and dilute coexisting phases. Semi-quantitative, in vitro approaches for measuring phase boundaries have proven very useful in determining some key features of biomolecular condensates, but these methods often lack the precision necessary for generating quantitative models. Therefore, there is a clear need for techniques that allow quantitation of coexisting dilute and dense phase concentrations of phase-separating biomolecules, especially in systems with more than one type of macromolecule. Here, we report the design and deployment of analytical High-Performance Liquid Chromatography (HPLC) for in vitro separation and quantification of distinct biomolecules that allows us to measure dilute and dense phase concentrations needed to reconstruct coexistence curves in multicomponent mixtures. This approach is label-free, detects lower amounts of material than is accessible with classic UV-spectrophotometers, is applicable to a broad range of macromolecules of interest, is a semi-high-throughput technique, and if needed, the macromolecules can be recovered for further use. The approach promises to provide quantitative insights into the balance of homotypic and heterotypic interactions in multicomponent phase-separating systems.
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Affiliation(s)
- Anne Bremer
- Department of Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Ammon E. Posey
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Madeleine B. Borgia
- Department of Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Wade M. Borcherds
- Department of Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Mina Farag
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Rohit V. Pappu
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
- Correspondence: (R.V.P.); (T.M.)
| | - Tanja Mittag
- Department of Structural Biology, St. Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
- Correspondence: (R.V.P.); (T.M.)
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11
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Kim HJ, Mohassel P, Donkervoort S, Guo L, O'Donovan K, Coughlin M, Lornage X, Foulds N, Hammans SR, Foley AR, Fare CM, Ford AF, Ogasawara M, Sato A, Iida A, Munot P, Ambegaonkar G, Phadke R, O'Donovan DG, Buchert R, Grimmel M, Töpf A, Zaharieva IT, Brady L, Hu Y, Lloyd TE, Klein A, Steinlin M, Kuster A, Mercier S, Marcorelles P, Péréon Y, Fleurence E, Manzur A, Ennis S, Upstill-Goddard R, Bello L, Bertolin C, Pegoraro E, Salviati L, French CE, Shatillo A, Raymond FL, Haack TB, Quijano-Roy S, Böhm J, Nelson I, Stojkovic T, Evangelista T, Straub V, Romero NB, Laporte J, Muntoni F, Nishino I, Tarnopolsky MA, Shorter J, Bönnemann CG, Taylor JP. Heterozygous frameshift variants in HNRNPA2B1 cause early-onset oculopharyngeal muscular dystrophy. Nat Commun 2022; 13:2306. [PMID: 35484142 PMCID: PMC9050844 DOI: 10.1038/s41467-022-30015-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 03/25/2022] [Indexed: 01/05/2023] Open
Abstract
Missense variants in RNA-binding proteins (RBPs) underlie a spectrum of disease phenotypes, including amyotrophic lateral sclerosis, frontotemporal dementia, and inclusion body myopathy. Here, we present ten independent families with a severe, progressive muscular dystrophy, reminiscent of oculopharyngeal muscular dystrophy (OPMD) but of much earlier onset, caused by heterozygous frameshift variants in the RBP hnRNPA2/B1. All disease-causing frameshift mutations abolish the native stop codon and extend the reading frame, creating novel transcripts that escape nonsense-mediated decay and are translated to produce hnRNPA2/B1 protein with the same neomorphic C-terminal sequence. In contrast to previously reported disease-causing missense variants in HNRNPA2B1, these frameshift variants do not increase the propensity of hnRNPA2 protein to fibrillize. Rather, the frameshift variants have reduced affinity for the nuclear import receptor karyopherin β2, resulting in cytoplasmic accumulation of hnRNPA2 protein in cells and in animal models that recapitulate the human pathology. Thus, we expand the phenotypes associated with HNRNPA2B1 to include an early-onset form of OPMD caused by frameshift variants that alter its nucleocytoplasmic transport dynamics. Missense variants in RNA-binding proteins underlie many diseases. Here the authors report an oculopharyngeal muscular dystrophy caused by heterozygous frameshift mutations in HNRNPA2B1 that alter its nucleocytoplasmic transport dynamics and result in cytoplasmic accumulation of hnRNPA2 protein.
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Affiliation(s)
- Hong Joo Kim
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Payam Mohassel
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Sandra Donkervoort
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Lin Guo
- Department of Biochemistry & Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States.,Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Kevin O'Donovan
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Maura Coughlin
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Xaviere Lornage
- Département Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Institut National de la Santé et de la Recherche Médicale U1258, Centre National de la Recherche Scientifique UMR7104, Université de Strasbourg, Illkirch, France
| | - Nicola Foulds
- Wessex Clinical Genetics Services, Princess Anne Hospital, Academic Unit of Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, England
| | - Simon R Hammans
- Wessex Neurological Centre, University Hospital Southampton, Southampton, UK
| | - A Reghan Foley
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Charlotte M Fare
- Department of Biochemistry & Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States
| | - Alice F Ford
- Department of Biochemistry & Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States
| | - Masashi Ogasawara
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), 4-1-1 Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan.,Medical Genome Center, NCNP, Kodaira, Tokyo, Japan
| | - Aki Sato
- Department of Neurology, Niigata City General Hospital, Niigata, Japan
| | | | - Pinki Munot
- The Dubowitz Neuromuscular Centre, NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, University College London, & Great Ormond Street Hospital Trust, London, UK
| | - Gautam Ambegaonkar
- Department of Paediatric Neurology, Cambridge University Hospital NHS Trust, Addenbrookes Hospital, Cambridge, CB2 0QQ, UK
| | - Rahul Phadke
- Division of Neuropathology, University College London Hospitals NHS Foundation Trust National Hospital for Neurology and Neurosurgery London, UK and Division of Neuropathology, UCL Institute of Neurology, Dubowitz Neuromuscular Centre, London, UK
| | - Dominic G O'Donovan
- Department of Histopathology Box 235, Level 5 John Bonnett Clinical Laboratories Addenbrooke's Hospital, Cambridge, UK
| | - Rebecca Buchert
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | - Mona Grimmel
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | - Ana Töpf
- John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Irina T Zaharieva
- The Dubowitz Neuromuscular Centre, NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, University College London, & Great Ormond Street Hospital Trust, London, UK
| | - Lauren Brady
- Division of Neuromuscular & Neurometabolic Disorders, Department of Pediatrics, McMaster University, Hamilton Health Sciences Centre, Hamilton, ON, Canada
| | - Ying Hu
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Thomas E Lloyd
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Andrea Klein
- Division of Neuropaediatrics, Development and Rehabilitation, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.,Pediatric Neurology, University Children's Hospital Basel, University of Basel, Basel, Switzerland
| | - Maja Steinlin
- Division of Neuropaediatrics, Development and Rehabilitation, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Alice Kuster
- Department of Neurometabolism, University Hospital of Nantes, Nantes, France
| | - Sandra Mercier
- CHU Nantes, Service de génétique médicale, Centre de Référence des Maladies Neuromusculaires AOC, 44000, Nantes, France.,Université de Nantes, CNRS, INSERM, l'institut du thorax, 44000, Nantes, France
| | - Pascale Marcorelles
- Service d'anatomopathologie, CHU Brest and EA 4685 LIEN, Université de Bretagne Occidentale, Brest, France
| | - Yann Péréon
- CHU de Nantes, Centre de Référence des Maladies Neuromusculaires, Filnemus, Euro-NMD, Hôtel-Dieu, Nantes, France
| | - Emmanuelle Fleurence
- Etablissement de Santé pour Enfants et Adolescents de la région Nantaise, Nantes, France
| | - Adnan Manzur
- The Dubowitz Neuromuscular Centre, NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, University College London, & Great Ormond Street Hospital Trust, London, UK
| | - Sarah Ennis
- Human Genetics and Genomic Medicine, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Rosanna Upstill-Goddard
- Human Genetics and Genomic Medicine, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Luca Bello
- Department of Neurosciences, DNS, University of Padova, Padova, Italy
| | - Cinzia Bertolin
- Clinical Genetics Unit, Department of Women and Children's Health, University of Padova, IRP Città della Speranza, Padova, Italy
| | - Elena Pegoraro
- Department of Neurosciences, DNS, University of Padova, Padova, Italy
| | - Leonardo Salviati
- Clinical Genetics Unit, Department of Women and Children's Health, CIR-Myo Myology Center, University of Padova, IRP Città della Speranza, Padova, Italy
| | | | - Andriy Shatillo
- Institute of Neurology, Psychiatry and Narcology of NAMS of Ukraine, Kharkiv, Ukraine
| | - F Lucy Raymond
- Cambridge Institute of Medical Research, University of Cambridge, Cambridge, UK
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | - Susana Quijano-Roy
- Neuromuscular Unit, Pediatric Neurology and ICU Department, Raymond Poincaré Hospital (UVSQ), AP-HP Université Paris-Saclay, Garches, France
| | - Johann Böhm
- Département Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Institut National de la Santé et de la Recherche Médicale U1258, Centre National de la Recherche Scientifique UMR7104, Université de Strasbourg, Illkirch, France
| | - Isabelle Nelson
- Sorbonne Université, INSERM, Centre of Research in Myology, UMRS974, Paris, France
| | - Tanya Stojkovic
- APHP, Centre de Référence des Maladies Neuromusculaires Nord/Est/Ile de France, Institut de Myologie, Sorbonne Université, Hôpital Pitié-Salpêtrière, Paris, France
| | - Teresinha Evangelista
- Unité de Morphologie Neuromusculaire, Institut de Myologie, Sorbonne Université, Hôpital Pitié-Salpêtrière, Paris, France
| | - Volker Straub
- John Walton Muscular Dystrophy Research Centre, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Norma B Romero
- APHP, Centre de Référence des Maladies Neuromusculaires Nord/Est/Ile de France, Institut de Myologie, Sorbonne Université, Hôpital Pitié-Salpêtrière, Paris, France.,Unité de Morphologie Neuromusculaire, Institut de Myologie, Sorbonne Université, Hôpital Pitié-Salpêtrière, Paris, France
| | - Jocelyn Laporte
- Département Médecine Translationnelle et Neurogénétique, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Institut National de la Santé et de la Recherche Médicale U1258, Centre National de la Recherche Scientifique UMR7104, Université de Strasbourg, Illkirch, France
| | - Francesco Muntoni
- The Dubowitz Neuromuscular Centre, NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, University College London, & Great Ormond Street Hospital Trust, London, UK
| | - Ichizo Nishino
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), 4-1-1 Ogawahigashi, Kodaira, Tokyo, 187-8502, Japan.,Medical Genome Center, NCNP, Kodaira, Tokyo, Japan
| | - Mark A Tarnopolsky
- Division of Neuromuscular & Neurometabolic Disorders, Department of Pediatrics, McMaster University, Hamilton Health Sciences Centre, Hamilton, ON, Canada
| | - James Shorter
- Department of Biochemistry & Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States
| | - Carsten G Bönnemann
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States.
| | - J Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, United States. .,Howard Hughes Medical Institute, Chevy Chase, MD, United States.
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