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Tilliole P, Fix S, Godin JD. hnRNPs: roles in neurodevelopment and implication for brain disorders. Front Mol Neurosci 2024; 17:1411639. [PMID: 39086926 PMCID: PMC11288931 DOI: 10.3389/fnmol.2024.1411639] [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: 04/03/2024] [Accepted: 06/17/2024] [Indexed: 08/02/2024] Open
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) constitute a family of multifunctional RNA-binding proteins able to process nuclear pre-mRNAs into mature mRNAs and regulate gene expression in multiple ways. They comprise at least 20 different members in mammals, named from A (HNRNP A1) to U (HNRNP U). Many of these proteins are components of the spliceosome complex and can modulate alternative splicing in a tissue-specific manner. Notably, while genes encoding hnRNPs exhibit ubiquitous expression, increasing evidence associate these proteins to various neurodevelopmental and neurodegenerative disorders, such as intellectual disability, epilepsy, microcephaly, amyotrophic lateral sclerosis, or dementias, highlighting their crucial role in the central nervous system. This review explores the evolution of the hnRNPs family, highlighting the emergence of numerous new members within this family, and sheds light on their implications for brain development.
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Affiliation(s)
- Pierre Tilliole
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, IGBMC, Illkirch, France
- Centre National de la Recherche Scientifique, CNRS, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, INSERM, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
| | - Simon Fix
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, IGBMC, Illkirch, France
- Centre National de la Recherche Scientifique, CNRS, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, INSERM, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
| | - Juliette D. Godin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, IGBMC, Illkirch, France
- Centre National de la Recherche Scientifique, CNRS, UMR7104, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, INSERM, U1258, Illkirch, France
- Université de Strasbourg, Strasbourg, France
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2
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Gedman GL, Kimball TH, Atkinson LL, Factor D, Vojtova G, Farias-Virgens M, Wright TF, White SA. CHIRP-Seq: FoxP2 transcriptional targets in zebra finch brain include numerous speech and language-related genes. RESEARCH SQUARE 2024:rs.3.rs-4542378. [PMID: 38978588 PMCID: PMC11230500 DOI: 10.21203/rs.3.rs-4542378/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Background Vocal learning is a rare, convergent trait that is fundamental to both human speech and birdsong. The Forkhead Box P2 (FoxP2) transcription factor appears necessary for both types of learned signals, as human mutations in FoxP2 result in speech deficits, and disrupting its expression in zebra finches impairs male-specific song learning. In juvenile and adult male finches, striatal FoxP2 mRNA and protein decline acutely within song-dedicated neurons during singing, indicating that its transcriptional targets are also behaviorally regulated. The identities of these targets in songbirds, and whether they differ across sex, development and/or behavioral conditions, are largely unknown. Results Here we used chromatin immunoprecipitation followed by sequencing (ChIP-Seq) to identify genomic sites bound by FoxP2 in male and female, juvenile and adult, and singing and non-singing birds. Our results suggest robust FoxP2 binding concentrated in putative promoter regions of genes. The number of genes likely to be bound by FoxP2 varied across conditions, suggesting specialized roles of the candidate targets related to sex, age, and behavioral state. We validated these binding targets both bioinformatically, with comparisons to previous studies and biochemically, with immunohistochemistry using an antibody for a putative target gene. Gene ontology analyses revealed enrichment for human speech- and language-related functions in males only, consistent with the sexual dimorphism of song learning in this species. Fewer such targets were found in juveniles relative to adults, suggesting an expansion of this regulatory network with maturation. The fewest speech-related targets were found in the singing condition, consistent with the well-documented singing-driven down-regulation of FoxP2 in the songbird striatum. Conclusions Overall, these data provide an initial catalog of the regulatory landscape of FoxP2 in an avian vocal learner, offering dozens of target genes for future study and providing insight into the molecular underpinnings of vocal learning.
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Brandão-Teles C, Antunes ASLM, de Moraes Vrechi TA, Martins-de-Souza D. The Roles of hnRNP Family in the Brain and Brain-Related Disorders. Mol Neurobiol 2024; 61:3578-3595. [PMID: 37999871 DOI: 10.1007/s12035-023-03747-4] [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: 08/31/2023] [Accepted: 10/25/2023] [Indexed: 11/25/2023]
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) belong to a complex family of RNA-binding proteins that are essential to control alternative splicing, mRNA trafficking, synaptic plasticity, stress granule formation, cell cycle regulation, and axonal transport. Over the past decade, hnRNPs have been associated with different brain disorders such as Alzheimer's disease, multiple sclerosis, and schizophrenia. Given their essential role in maintaining cell function and integrity, it is not surprising that dysregulated hnRNP levels lead to neurological implications. This review aims to explore the primary functions of hnRNPs in neurons, oligodendrocytes, microglia, and astrocytes, and their roles in brain disorders. We also discuss proteomics and other technologies and their potential for studying and evaluating hnRNPs in brain disorders, including the discovery of new therapeutic targets and possible pharmacological interventions.
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Affiliation(s)
- Caroline Brandão-Teles
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil.
| | - André S L M Antunes
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Talita Aparecida de Moraes Vrechi
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Daniel Martins-de-Souza
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, Brazil.
- D'Or Institute for Research and Education (IDOR), São Paulo, Brazil.
- Experimental Medicine Research Cluster (EMRC), University of Campinas, Campinas, SP, 13083-862, Brazil.
- INCT in Modelling Human Complex Diseases with 3D Platforms (Model3D), São Paulo, Brazil.
- Conselho Nacional de Desenvolvimento Científico e Tecnológico, Instituto Nacional de Biomarcadores em Neuropsiquiatria, São Paulo, Brazil.
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4
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Tetter S, Arseni D, Murzin AG, Buhidma Y, Peak-Chew SY, Garringer HJ, Newell KL, Vidal R, Apostolova LG, Lashley T, Ghetti B, Ryskeldi-Falcon B. TAF15 amyloid filaments in frontotemporal lobar degeneration. Nature 2024; 625:345-351. [PMID: 38057661 PMCID: PMC10781619 DOI: 10.1038/s41586-023-06801-2] [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: 04/13/2023] [Accepted: 10/30/2023] [Indexed: 12/08/2023]
Abstract
Frontotemporal lobar degeneration (FTLD) causes frontotemporal dementia (FTD), the most common form of dementia after Alzheimer's disease, and is often also associated with motor disorders1. The pathological hallmarks of FTLD are neuronal inclusions of specific, abnormally assembled proteins2. In the majority of cases the inclusions contain amyloid filament assemblies of TAR DNA-binding protein 43 (TDP-43) or tau, with distinct filament structures characterizing different FTLD subtypes3,4. The presence of amyloid filaments and their identities and structures in the remaining approximately 10% of FTLD cases are unknown but are widely believed to be composed of the protein fused in sarcoma (FUS, also known as translocated in liposarcoma). As such, these cases are commonly referred to as FTLD-FUS. Here we used cryogenic electron microscopy (cryo-EM) to determine the structures of amyloid filaments extracted from the prefrontal and temporal cortices of four individuals with FTLD-FUS. Surprisingly, we found abundant amyloid filaments of the FUS homologue TATA-binding protein-associated factor 15 (TAF15, also known as TATA-binding protein-associated factor 2N) rather than of FUS itself. The filament fold is formed from residues 7-99 in the low-complexity domain (LCD) of TAF15 and was identical between individuals. Furthermore, we found TAF15 filaments with the same fold in the motor cortex and brainstem of two of the individuals, both showing upper and lower motor neuron pathology. The formation of TAF15 amyloid filaments with a characteristic fold in FTLD establishes TAF15 proteinopathy in neurodegenerative disease. The structure of TAF15 amyloid filaments provides a basis for the development of model systems of neurodegenerative disease, as well as for the design of diagnostic and therapeutic tools targeting TAF15 proteinopathy.
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Affiliation(s)
| | - Diana Arseni
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | | | - Yazead Buhidma
- Department of Neurodegenerative Diseases, UCL Queen Square Institute of Neurology, London, UK
| | | | - Holly J Garringer
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kathy L Newell
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ruben Vidal
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Liana G Apostolova
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Tammaryn Lashley
- Department of Neurodegenerative Diseases, UCL Queen Square Institute of Neurology, London, UK
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, London, UK
| | - Bernardino Ghetti
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
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5
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Jiang X, Gatt A, Lashley T. HnRNP Pathologies in Frontotemporal Lobar Degeneration. Cells 2023; 12:1633. [PMID: 37371103 DOI: 10.3390/cells12121633] [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: 05/04/2023] [Revised: 06/06/2023] [Accepted: 06/09/2023] [Indexed: 06/29/2023] Open
Abstract
Frontotemporal dementia (FTD) is the second most common form of young-onset (<65 years) dementia. Clinically, it primarily manifests as a disorder of behavioural, executive, and/or language functions. Pathologically, frontotemporal lobar degeneration (FTLD) is the predominant cause of FTD. FTLD is a proteinopathy, and the main pathological proteins identified so far are tau, TAR DNA-binding protein 43 (TDP-43), and fused in sarcoma (FUS). As TDP-43 and FUS are members of the heterogeneous ribonucleic acid protein (hnRNP) family, many studies in recent years have expanded the research on the relationship between other hnRNPs and FTLD pathology. Indeed, these studies provide evidence for an association between hnRNP abnormalities and FTLD. In particular, several studies have shown that multiple hnRNPs may exhibit nuclear depletion and cytoplasmic mislocalisation within neurons in FTLD cases. However, due to the diversity and complex association of hnRNPs, most studies are still at the stage of histological discovery of different hnRNP abnormalities in FTLD. We herein review the latest studies relating hnRNPs to FTLD. Together, these studies outline an important role of multiple hnRNPs in the pathogenesis of FTLD and suggest that future research into FTLD should include the whole spectrum of this protein family.
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Affiliation(s)
- Xinwa Jiang
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Ariana Gatt
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Tammaryn Lashley
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London WC1N 1PJ, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
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Honda H, Yoshimura M, Arahata H, Yagita K, Sadashima S, Hamasaki H, Shijo M, Koyama S, Noguchi H, Sasagasako N. Mutated FUS in familial amyotrophic lateral sclerosis involves multiple hnRNPs in the formation of neuronal cytoplasmic inclusions. J Neuropathol Exp Neurol 2023; 82:231-241. [PMID: 36592411 DOI: 10.1093/jnen/nlac124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Fused in sarcoma (FUS), coded by FUS, is a heterogeneous nuclear ribonucleoprotein (hnRNP). FUS mutations are among the major mutations in familial amyotrophic lateral sclerosis (ALS-FUS: ALS6). The pathological hallmarks of ALS-FUS are FUS-positive neuronal cytoplasmic inclusions (NCI). We examined various hnRNPs in FUS NCIs in the hippocampus in ALS-FUS cases with different FUS mutations (Case 1, H517P; Case 2, R521C). We also examined TDP43-positive NCIs in sporadic ALS hippocampi. Immunohistochemistry was performed using primary antibodies against FUS, p-TDP43, TDP43, hnRNPA1, hnRNPD, PCBP1, PCBP2, and p62. Numerous FUS inclusions were found in the hippocampal granule and pyramidal cell layers. Double immunofluorescence revealed colocalization of FUS and p-TDP43, and FUS and PCBP2 (p-TDP43/FUS: 64.3%, PCBP2/FUS: 23.9%). Colocalization of FUS and PCBP1, however, was rare (PCBP1/FUS: 7.6%). In the hippocampi of patients with sporadic ALS, no colocalization was observed between TDP43-positive inclusions and other hnRNPs. This is the first study to show that FUS inclusions colocalize with other hnRNPs, such as TDP43, PCBP2, and PCBP1. These findings suggest that in ALS-FUS, FUS inclusions are the initiators, followed by alterations of multiple other hnRNPs, resulting in impaired RNA metabolism.
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Affiliation(s)
- Hiroyuki Honda
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Motoi Yoshimura
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.,Department of Neurology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hajime Arahata
- Division of Neurology, Department of Neurology, Neuro Muscular Center, National Omuta Hospital, Fukuoka, Japan
| | - Kaoru Yagita
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shoko Sadashima
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.,Department of Neurology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hideomi Hamasaki
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masahiro Shijo
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Sachiko Koyama
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hideko Noguchi
- Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Naokazu Sasagasako
- Division of Neurology, Department of Neurology, Neuro Muscular Center, National Omuta Hospital, Fukuoka, Japan
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7
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Montalbano M, Jaworski E, Garcia S, Ellsworth A, McAllen S, Routh A, Kayed R. Tau Modulates mRNA Transcription, Alternative Polyadenylation Profiles of hnRNPs, Chromatin Remodeling and Spliceosome Complexes. Front Mol Neurosci 2021; 14:742790. [PMID: 34924950 PMCID: PMC8678415 DOI: 10.3389/fnmol.2021.742790] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 11/09/2021] [Indexed: 11/13/2022] Open
Abstract
Tau protein is a known contributor in several neurodegenerative diseases, including Alzheimer’s disease (AD) and frontotemporal dementia (FTD). It is well-established that tau forms pathological aggregates and fibrils in these diseases. Tau has been observed within the nuclei of neurons, but there is a gap in understanding regarding the mechanism by which tau modulates transcription. We are interested in the P301L mutation of tau, which has been associated with FTD and increased tau aggregation. Our study utilized tau-inducible HEK (iHEK) cells to reveal that WT and P301L tau distinctively alter the transcription and alternative polyadenylation (APA) profiles of numerous nuclear precursors mRNAs, which then translate to form proteins involved in chromatin remodeling and splicing. We isolated total mRNA before and after over-expressing tau and then performed Poly(A)-ClickSeq (PAC-Seq) to characterize mRNA expression and APA profiles. We characterized changes in Gene Ontology (GO) pathways using EnrichR and Gene Set Enrichment Analysis (GSEA). We observed that P301L tau up-regulates genes associated with reactive oxygen species responsiveness as well as genes involved in dendrite, microtubule, and nuclear body/speckle formation. The number of genes regulated by WT tau is greater than the mutant form, which indicates that the P301L mutation causes loss-of-function at the transcriptional level. WT tau up-regulates genes contributing to cytoskeleton-dependent intracellular transport, microglial activation, microtubule and nuclear chromatin organization, formation of nuclear bodies and speckles. Interestingly, both WT and P301L tau commonly down-regulate genes responsible for ubiquitin-proteosome system. In addition, WT tau significantly down-regulates several genes implicated in chromatin remodeling and nucleosome organization. Although there are limitations inherent to the model systems used, this study will improve understanding regarding the nuclear impact of tau at the transcriptional and post-transcriptional level. This study also illustrates the potential impact of P301L tau on the human brain genome during early phases of pathogenesis.
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Affiliation(s)
- Mauro Montalbano
- Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, TX, United States.,Departments of Neurology, Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX, United States
| | - Elizabeth Jaworski
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States
| | - Stephanie Garcia
- Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, TX, United States.,Departments of Neurology, Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX, United States
| | - Anna Ellsworth
- Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, TX, United States.,Departments of Neurology, Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX, United States
| | - Salome McAllen
- Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, TX, United States.,Departments of Neurology, Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX, United States
| | - Andrew Routh
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States.,Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, United States
| | - Rakez Kayed
- Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, TX, United States.,Departments of Neurology, Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX, United States
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8
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Knock-Down of Heterogeneous Nuclear Ribonucleoprotein A1 Results in Neurite Damage, Altered Stress Granule Biology, and Cellular Toxicity in Differentiated Neuronal Cells. eNeuro 2021; 8:ENEURO.0350-21.2021. [PMID: 34697074 PMCID: PMC8607908 DOI: 10.1523/eneuro.0350-21.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/29/2021] [Accepted: 10/18/2021] [Indexed: 12/13/2022] Open
Abstract
Heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) is an RNA binding protein (RBP) that is localized within neurons and plays crucial roles in RNA metabolism. Its importance in neuronal functioning is underscored from the study of its pathogenic features in many neurodegenerative diseases where neuronal hnRNP A1 is mislocalized from the nucleus to the cytoplasm resulting in loss of hnRNP A1 function. Here, we model hnRNP A1 loss-of-function by siRNA-mediated knock-down in differentiated Neuro-2a cells. Through RNA sequencing (RNA-seq) followed by gene ontology (GO) analyses, we show that hnRNP A1 is involved in important biological processes, including RNA metabolism, neuronal function, neuronal morphology, neuronal viability, and stress granule (SG) formation. We further confirmed several of these roles by showing that hnRNP A1 knock-down results in a reduction of neurite outgrowth, increase in cell cytotoxicity and changes in SG formation. In summary, these findings indicate that hnRNP A1 loss-of-function contributes to neuronal dysfunction and cell death and implicates hnRNP A1 dysfunction in the pathogenesis of neurodegenerative diseases.
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9
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Mann JR, Donnelly CJ. RNA modulates physiological and neuropathological protein phase transitions. Neuron 2021; 109:2663-2681. [PMID: 34297914 PMCID: PMC8434763 DOI: 10.1016/j.neuron.2021.06.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/21/2021] [Accepted: 06/16/2021] [Indexed: 12/24/2022]
Abstract
Aggregation of RNA-binding proteins (RBPs) is a pathological hallmark of neurodegenerative disorders like amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). In these diseases, TDP-43 and FUS RBPs are depleted from the nuclear compartment, where they are normally localized, and found within cytoplasmic inclusions in degenerating regions of affected individuals' postmortem tissue. The mechanisms responsible for aggregation of these proteins has remained elusive, but recent studies suggest liquid-liquid phase separation (LLPS) might serve as a critical nucleation step in formation of pathological inclusions. The process of phase separation also underlies the formation and maintenance of several functional membraneless organelles (MLOs) throughout the cell, some of which contain TDP-43, FUS, and other disease-linked RBPs. One common ligand of disease-linked RBPs, RNA, is a major component of MLOs containing RBPs and has been demonstrated to be a strong modulator of RBP phase transitions. Although early evidence suggested a largely synergistic effect of RNA on RBP phase separation and MLO assembly, recent work indicates that RNA can also antagonize RBP phase behavior under certain physiological and pathological conditions. In this review, we describe the mechanisms underlying RNA-mediated phase transitions of RBPs and examine the molecular properties of these interactions, such as RNA length, sequence, and secondary structure, that mediate physiological or pathological LLPS.
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Affiliation(s)
- Jacob R Mann
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15213, USA; LiveLikeLouCenter for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA 15213, USA; Center for Protein Conformational Diseases, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Christopher J Donnelly
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; LiveLikeLouCenter for ALS Research, University of Pittsburgh Brain Institute, Pittsburgh, PA 15213, USA; Center for Protein Conformational Diseases, University of Pittsburgh, Pittsburgh, PA 15213, USA; Pittsburgh Institute for Neurodegeneration, University of Pittsburgh, Pittsburgh PA 15213.
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10
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Sternburg EL, Gruijs da Silva LA, Dormann D. Post-translational modifications on RNA-binding proteins: accelerators, brakes, or passengers in neurodegeneration? Trends Biochem Sci 2021; 47:6-22. [PMID: 34366183 DOI: 10.1016/j.tibs.2021.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/09/2021] [Accepted: 07/19/2021] [Indexed: 02/07/2023]
Abstract
RNA-binding proteins (RBPs) are critical players in RNA expression and metabolism, thus, the proper regulation of this class of proteins is critical for cellular health. Regulation of RBPs often occurs through post-translational modifications (PTMs), which allow the cell to quickly and efficiently respond to cellular and environmental stimuli. PTMs have recently emerged as important regulators of RBPs implicated in neurodegenerative disorders, in particular amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Here, we summarize how disease-associated PTMs influence the biophysical properties, molecular interactions, subcellular localization, and function of ALS/FTD-linked RBPs, such as FUS and TDP-43. We will discuss how PTMs are believed to play pathological, protective, or ambiguous roles in these neurodegenerative disorders.
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Affiliation(s)
- Erin L Sternburg
- Johannes Gutenberg-Universität (JGU) Mainz, Faculty of Biology, Mainz, Germany
| | - Lara A Gruijs da Silva
- Johannes Gutenberg-Universität (JGU) Mainz, Faculty of Biology, Mainz, Germany; Graduate School of Systemic Neurosciences (GSN), Munich, Germany
| | - Dorothee Dormann
- Johannes Gutenberg-Universität (JGU) Mainz, Faculty of Biology, Mainz, Germany; Institute of Molecular Biology (IMB), Mainz, Germany.
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11
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Baade I, Hutten S, Sternburg EL, Pörschke M, Hofweber M, Dormann D, Kehlenbach RH. The RNA-binding protein FUS is chaperoned and imported into the nucleus by a network of import receptors. J Biol Chem 2021; 296:100659. [PMID: 33857479 PMCID: PMC8131929 DOI: 10.1016/j.jbc.2021.100659] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 03/31/2021] [Accepted: 04/09/2021] [Indexed: 12/11/2022] Open
Abstract
Fused in sarcoma (FUS) is a predominantly nuclear RNA-binding protein with key functions in RNA processing and DNA damage repair. Defects in nuclear import of FUS have been linked to severe neurodegenerative diseases; hence, it is of great interest to understand this process and how it is dysregulated in disease. Transportin-1 (TNPO1) and the closely related transportin-2 have been identified as major nuclear import receptors of FUS. They bind to the C-terminal nuclear localization signal of FUS and mediate the protein's nuclear import and at the same time also suppress aberrant phase transitions of FUS in the cytoplasm. Whether FUS can utilize other nuclear transport receptors for the purpose of import and chaperoning has not been examined so far. Here, we show that FUS directly binds to different import receptors in vitro. FUS formed stable complexes not only with TNPO1 but also with transportin-3, importin β, importin 7, or the importin β/7 heterodimer. Binding of these alternative import receptors required arginine residues within FUS-RG/RGG motifs and was weakened by arginine methylation. Interaction with these importins suppressed FUS phase separation and reduced its sequestration into stress granules. In a permeabilized cell system, we further showed that transportin-3 had the capacity to import FUS into the nucleus, albeit with lower efficiency than TNPO1. Our data suggest that aggregation-prone RNA-binding proteins such as FUS may utilize a network of importins for chaperoning and import, similar to histones and ribosomal proteins.
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Affiliation(s)
- Imke Baade
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Saskia Hutten
- BioMedical Center (BMC), Cell Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Erin L Sternburg
- BioMedical Center (BMC), Cell Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Marius Pörschke
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Mario Hofweber
- BioMedical Center (BMC), Cell Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Dorothee Dormann
- BioMedical Center (BMC), Cell Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, GZMB, Georg-August-University Göttingen, Göttingen, Germany.
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Low YH, Asi Y, Foti SC, Lashley T. Heterogeneous Nuclear Ribonucleoproteins: Implications in Neurological Diseases. Mol Neurobiol 2021; 58:631-646. [PMID: 33000450 PMCID: PMC7843550 DOI: 10.1007/s12035-020-02137-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/17/2020] [Indexed: 12/13/2022]
Abstract
Heterogenous nuclear ribonucleoproteins (hnRNPs) are a complex and functionally diverse family of RNA binding proteins with multifarious roles. They are involved, directly or indirectly, in alternative splicing, transcriptional and translational regulation, stress granule formation, cell cycle regulation, and axonal transport. It is unsurprising, given their heavy involvement in maintaining functional integrity of the cell, that their dysfunction has neurological implications. However, compared to their more established roles in cancer, the evidence of hnRNP implication in neurological diseases is still in its infancy. This review aims to consolidate the evidences for hnRNP involvement in neurological diseases, with a focus on spinal muscular atrophy (SMA), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), multiple sclerosis (MS), congenital myasthenic syndrome (CMS), and fragile X-associated tremor/ataxia syndrome (FXTAS). Understanding more about hnRNP involvement in neurological diseases can further elucidate the pathomechanisms involved in these diseases and perhaps guide future therapeutic advances.
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Affiliation(s)
- Yi-Hua Low
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Disorders, UCL Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
- Duke-NUS Medical School, Singapore, Singapore
| | - Yasmine Asi
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Disorders, UCL Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Sandrine C Foti
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Disorders, UCL Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Tammaryn Lashley
- The Queen Square Brain Bank for Neurological Disorders, Department of Clinical and Movement Disorders, UCL Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK.
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, UK.
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Johnson MA, Deng Q, Taylor G, McEachin ZT, Chan AWS, Root J, Bassell GJ, Kukar T. Divergent FUS phosphorylation in primate and mouse cells following double-strand DNA damage. Neurobiol Dis 2020; 146:105085. [PMID: 32950644 PMCID: PMC8064403 DOI: 10.1016/j.nbd.2020.105085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 09/10/2020] [Accepted: 09/15/2020] [Indexed: 12/15/2022] Open
Abstract
Fused in sarcoma (FUS) is a RNA/DNA protein involved in multiple nuclear and cytoplasmic functions including transcription, splicing, mRNA trafficking, and stress granule formation. To accomplish these many functions, FUS must shuttle between cellular compartments in a highly regulated manner. When shuttling is disrupted, FUS abnormally accumulates into cytoplasmic inclusions that can be toxic. Disrupted shuttling of FUS into the nucleus is a hallmark of ~10% of frontotemporal lobar degeneration (FTLD) cases, the neuropathology that underlies frontotemporal dementia (FTD). Multiple pathways are known to disrupt nuclear/cytoplasmic shuttling of FUS. In earlier work, we discovered that double-strand DNA breaks (DSBs) trigger DNA-dependent protein kinase (DNA-PK) to phosphorylate FUS (p-FUS) at N-terminal residues leading to the cytoplasmic accumulation of FUS. Therefore, DNA damage may contribute to the development of FTLD pathology with FUS inclusions. In the present study, we examined how DSBs effect FUS phosphorylation in various primate and mouse cellular models. All cell lines derived from human and non-human primates exhibit N-terminal FUS phosphorylation following calicheamicin γ1 (CLM) induced DSBs. In contrast, we were unable to detect FUS phosphorylation in mouse-derived primary neurons or immortalized cell lines regardless of CLM treatment, duration, or concentration. Despite DNA damage induced by CLM treatment, we find that mouse cells do not phosphorylate FUS, likely due to reduced levels and activity of DNA-PK compared to human cells. Taken together, our work reveals that mouse-derived cellular models regulate FUS in an anomalous manner compared to primate cells. This raises the possibility that mouse models may not fully recapitulate the pathogenic cascades that lead to FTLD with FUS pathology.
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Affiliation(s)
- Michelle A Johnson
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Qiudong Deng
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Georgia Taylor
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Zachary T McEachin
- Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America; Department of Cell Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Laboratory of Translational Cell Biology, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Anthony W S Chan
- Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America; Department of Human Genetics, Emory University, School of Medicine, Atlanta, GA, United States of America; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, 954 Gatewood Rd, NE, Atlanta, GA, United States of America
| | - Jessica Root
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Gary J Bassell
- Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America; Department of Cell Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Laboratory of Translational Cell Biology, Emory University, School of Medicine, Atlanta, GA, United States of America
| | - Thomas Kukar
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, GA, United States of America; Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, GA, United States of America; Department of Neurology, Emory University, School of Medicine, Atlanta, GA, United States of America.
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The role of hnRNPs in frontotemporal dementia and amyotrophic lateral sclerosis. Acta Neuropathol 2020; 140:599-623. [PMID: 32748079 PMCID: PMC7547044 DOI: 10.1007/s00401-020-02203-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 12/12/2022]
Abstract
Dysregulated RNA metabolism is emerging as a crucially important mechanism underpinning the pathogenesis of frontotemporal dementia (FTD) and the clinically, genetically and pathologically overlapping disorder of amyotrophic lateral sclerosis (ALS). Heterogeneous nuclear ribonucleoproteins (hnRNPs) comprise a family of RNA-binding proteins with diverse, multi-functional roles across all aspects of mRNA processing. The role of these proteins in neurodegeneration is far from understood. Here, we review some of the unifying mechanisms by which hnRNPs have been directly or indirectly linked with FTD/ALS pathogenesis, including their incorporation into pathological inclusions and their best-known roles in pre-mRNA splicing regulation. We also discuss the broader functionalities of hnRNPs including their roles in cryptic exon repression, stress granule assembly and in co-ordinating the DNA damage response, which are all emerging pathogenic themes in both diseases. We then present an integrated model that depicts how a broad-ranging network of pathogenic events can arise from declining levels of functional hnRNPs that are inadequately compensated for by autoregulatory means. Finally, we provide a comprehensive overview of the most functionally relevant cellular roles, in the context of FTD/ALS pathogenesis, for hnRNPs A1-U.
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15
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Hutten S, Dormann D. Nucleocytoplasmic transport defects in neurodegeneration — Cause or consequence? Semin Cell Dev Biol 2020; 99:151-162. [DOI: 10.1016/j.semcdb.2019.05.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 05/21/2019] [Accepted: 05/21/2019] [Indexed: 12/12/2022]
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Gittings LM, Foti SC, Benson BC, Gami-Patel P, Isaacs AM, Lashley T. Heterogeneous nuclear ribonucleoproteins R and Q accumulate in pathological inclusions in FTLD-FUS. Acta Neuropathol Commun 2019; 7:18. [PMID: 30755280 PMCID: PMC6371513 DOI: 10.1186/s40478-019-0673-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 02/03/2019] [Indexed: 12/14/2022] Open
Abstract
Frontotemporal lobar degeneration (FTLD) is pathologically subdivided based on the presence of particular pathological proteins that are identified in inclusion bodies observed post-mortem. The FTLD-FUS subgroup is defined by the presence of the fused in sarcoma protein (FUS) in pathological inclusions. FUS is a heterogeneous nuclear ribonucleoprotein (hnRNP) protein and a member of the FET (FUS, EWS, TAF15) protein family. It shuttles between the nucleus and cytoplasm, and has been implicated in many cellular functions including translation, splicing, and RNA transport. EWS, TAF15 and the nuclear import receptor transportin have been shown to co-accumulate with FUS in neuronal inclusions specifically in FTLD-FUS, with transportin-positive inclusions most frequently observed. Here, we report the identification of hnRNP R and hnRNP Q in neuronal cytoplasmic and intranuclear inclusions in the frontal cortex and hippocampus of FTLD-FUS patients, as frequently as transportin. hnRNP R and hnRNP Q were not found in the characteristic pathological inclusions observed in FTLD-TDP (subtypes A-C). Additionally, we studied the expression of hnRNP R in the frontal and temporal cortices from patients with FTLD and found significantly increased expression of the heterogeneous nuclear ribonucleoprotein R in several FTLD disease groups. Our identification of the frequent presence of hnRNP R and hnRNP Q in FTLD-FUS inclusions suggests a potential role for these hnRNPs in FTLD-FUS pathogenesis and supports the role of dysfunctional RNA metabolism in FTLD.
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Borroni B, Alberici A, Buratti E. Review: Molecular pathology of frontotemporal lobar degenerations. Neuropathol Appl Neurobiol 2019; 45:41-57. [DOI: 10.1111/nan.12534] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 12/04/2018] [Indexed: 02/07/2023]
Affiliation(s)
- B. Borroni
- Neurology Clinic; Department of Clinical and Experimental Sciences; University of Brescia; Brescia Italy
| | - A. Alberici
- Neurology Clinic; Department of Clinical and Experimental Sciences; University of Brescia; Brescia Italy
| | - E. Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB); Trieste Italy
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Kahl A, Blanco I, Jackman K, Baskar J, Milaganur Mohan H, Rodney-Sandy R, Zhang S, Iadecola C, Hochrainer K. Cerebral ischemia induces the aggregation of proteins linked to neurodegenerative diseases. Sci Rep 2018; 8:2701. [PMID: 29426953 PMCID: PMC5807442 DOI: 10.1038/s41598-018-21063-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 01/29/2018] [Indexed: 12/21/2022] Open
Abstract
Protein aggregation critically affects cell viability in neurodegenerative diseases, but whether this also occurs in ischemic brain injury remains elusive. Prior studies report the post-ischemic aggregation of ubiquitin, small ubiquitin-related modifier (SUMO) and ribosomes, however whether other proteins are also affected is unknown. Here we employed a proteomic approach to identify the insoluble, aggregated proteome after cerebral ischemia. Mice underwent transient middle cerebral artery occlusion or sham-surgery. After 1-hour reperfusion, prior to apparent brain injury, mice were sacrificed and detergent-insoluble proteins were obtained and identified by nanoLC-MS/MS. Naturally existing insoluble proteins were determined in sham controls and aggregated proteins after cerebral ischemia/reperfusion were identified. Selected aggregated proteins found by proteomics were biochemically verified and aggregation propensities were studied during ischemia with or without reperfusion. We found that ischemia/reperfusion induces the aggregation of RNA-binding and heat-shock proteins, ubiquitin, SUMO and other proteins involved in cell signalling. RNA-binding proteins constitute the largest group of aggregating proteins in ischemia. These include TDP43, FUS, hnRNPA1, PSF/SFPQ and p54/NONO, all of which have been linked to neurodegeneration associated with amyotrophic lateral sclerosis and frontotemporal dementia. The aggregation of neurodegeneration-related disease proteins in cerebral ischemia unveils a previously unappreciated molecular overlap between neurodegenerative diseases and ischemic stroke.
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Affiliation(s)
- Anja Kahl
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY10065, USA
| | - Ismary Blanco
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY10065, USA
| | - Katherine Jackman
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY10065, USA
| | - Juhi Baskar
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY10065, USA
| | - Harihar Milaganur Mohan
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY10065, USA
| | - Reunet Rodney-Sandy
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY10065, USA
| | - Sheng Zhang
- Institute of Biotechnology and Life Sciences Biotechnologies, Cornell University, Ithaca, NY14853, USA
| | - Costantino Iadecola
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY10065, USA
| | - Karin Hochrainer
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY10065, USA.
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Davidson YS, Robinson AC, Flood L, Rollinson S, Benson BC, Asi YT, Richardson A, Jones M, Snowden JS, Pickering-Brown S, Lashley T, Mann DMA. Heterogeneous ribonuclear protein E2 (hnRNP E2) is associated with TDP-43-immunoreactive neurites in Semantic Dementia but not with other TDP-43 pathological subtypes of Frontotemporal Lobar Degeneration. Acta Neuropathol Commun 2017; 5:54. [PMID: 28666471 PMCID: PMC5493127 DOI: 10.1186/s40478-017-0454-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 06/14/2017] [Indexed: 02/07/2023] Open
Abstract
Frontotemporal Lobar Degeneration (FTLD) encompasses certain related neurodegenerative disorders which alter personality and cognition. Heterogeneous ribonuclear proteins (hnRNPs) maintain RNA metabolism and changes in their function may underpin the pathogenesis of FTLD. Immunostaining for hnRNP E2 was performed on sections of frontal and temporal cortex with hippocampus from 80 patients with FTLD, stratified by pathology into FTLD-tau and FTLD-TDP type A, B and C subtypes, and by genetics into patients with C9orf72 expansions, MAPT or GRN mutations, or those with no known mutation, and on 10 healthy controls. Semi-quantitative analysis assessed hnRNP staining in frontal and temporal cortex, and in dentate gyrus (DG) of hippocampus, in the different pathology and genetic groups. We find that hnRNP E2 immunostaining detects the TDP-43 positive dystrophic neurites (DN) within frontal and temporal cortex, and the neuronal cytoplasmic inclusions (NCI) seen in DG granule cells, characteristic of patients with Semantic Dementia (SD) and type C TDP-43 pathology, but did not detect TDP-43 or tau inclusions in any of the other pathological or genetic variants of FTLD. Double immunofluorescence for hnRNP E2 and TDP-43 showed most TDP-43 immunopositive DN to contain hnRNP E2. Present findings indicate an association between TDP-43 and hnRNP E2 which might underlie the pathogenetic mechanism of this form of FTLD.
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Affiliation(s)
- Yvonne S Davidson
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Salford Royal Hospital, M6 8HD, Salford, UK
| | - Andrew C Robinson
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Salford Royal Hospital, M6 8HD, Salford, UK
| | - Louis Flood
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Salford Royal Hospital, M6 8HD, Salford, UK
| | - Sara Rollinson
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, A V Hill Building, Manchester, M13 9PT, UK
| | - Bridget C Benson
- Institute of Neurology, Queen Square Brain Bank for Neurological Disorders, Department of Molecular Neuroscience, University College London, 1 Wakefield St, London, WC1N 1PJ, UK
| | - Yasmine T Asi
- Institute of Neurology, Queen Square Brain Bank for Neurological Disorders, Department of Molecular Neuroscience, University College London, 1 Wakefield St, London, WC1N 1PJ, UK
| | - Anna Richardson
- Cerebral Function Unit, Greater Manchester Neurosciences Centre, Salford Royal Hospital, Stott Lane, M6 8HD, Salford, UK
| | - Matthew Jones
- Cerebral Function Unit, Greater Manchester Neurosciences Centre, Salford Royal Hospital, Stott Lane, M6 8HD, Salford, UK
| | - Julie S Snowden
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Salford Royal Hospital, M6 8HD, Salford, UK
- Cerebral Function Unit, Greater Manchester Neurosciences Centre, Salford Royal Hospital, Stott Lane, M6 8HD, Salford, UK
| | - Stuart Pickering-Brown
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, A V Hill Building, Manchester, M13 9PT, UK
| | - Tammaryn Lashley
- Institute of Neurology, Queen Square Brain Bank for Neurological Disorders, Department of Molecular Neuroscience, University College London, 1 Wakefield St, London, WC1N 1PJ, UK
| | - David M A Mann
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Salford Royal Hospital, M6 8HD, Salford, UK.
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Davidson YS, Flood L, Robinson AC, Nihei Y, Mori K, Rollinson S, Richardson A, Benson BC, Jones M, Snowden JS, Pickering-Brown S, Haass C, Lashley T, Mann DMA. Heterogeneous ribonuclear protein A3 (hnRNP A3) is present in dipeptide repeat protein containing inclusions in Frontotemporal Lobar Degeneration and Motor Neurone disease associated with expansions in C9orf72 gene. Acta Neuropathol Commun 2017; 5:31. [PMID: 28431575 PMCID: PMC5399321 DOI: 10.1186/s40478-017-0437-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 04/12/2017] [Indexed: 12/12/2022] Open
Abstract
Frontotemporal Lobar Degeneration (FTLD) encompasses certain related neurodegenerative disorders which alter behaviour, personality and language. Heterogeneous ribonuclear proteins (hnRNPs) maintain RNA metabolism and changes in their function may underpin the pathogenesis of FTLD. Immunostaining for hnRNP A1, A2/B1 and A3 was performed on sections of temporal cortex with hippocampus from 61 patients with FTLD, stratified by pathological hallmarks into FTLD-tau and FTLD-TDP type A, B and C subtypes, and by genetics into patients with C9orf72 expansions, MAPT or GRN mutations, or those without known mutation. Four patients with Motor Neurone Disease (MND) with C9orf72 expansions and 10 healthy controls were also studied. Semi-quantitative analysis assessed hnRNP staining intensity in dentate gyrus (DG) and CA4 region of hippocampus, and temporal cortex (Tcx) in the different pathological and genetic groups. Immunostaining for hnRNP A1, A2/B1 and A3 revealed no consistent changes in pattern or amount of physiological staining across any of the pathological or genetic groups. No immunostaining of any inclusions resembling TDP-43 immunoreactive neuronal cytoplasmic inclusions or dystrophic neurites, was seen in either Tcx or DG of the hippocampus in any of the FTLD cases investigated for hnRNP A1, A2/B1 and A3. However, immunostaining for hnRNP A3 showed that inclusion bodies, resembling those TDP-43 negative, p62-immunopositive structures containing dipeptide repeat proteins (DPR) were variably observed in hippocampus and cerebellum. The proportion of cases showing hnRNP A3-immunoreactive DPR, and the number of hnRNP A3-positive inclusions within cases, was significantly greater in DG than in cells of CA4 region and cerebellum, but the latter was significantly less in all three regions compared to that detected by p62 immunostaining.
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