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Guha A, Husain MA, Si Y, Nabors LB, Filippova N, Promer G, Smith R, King PH. RNA regulation of inflammatory responses in glia and its potential as a therapeutic target in central nervous system disorders. Glia 2023; 71:485-508. [PMID: 36380708 DOI: 10.1002/glia.24288] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/29/2022] [Accepted: 10/14/2022] [Indexed: 11/17/2022]
Abstract
A major hallmark of neuroinflammation is the activation of microglia and astrocytes with the induction of inflammatory mediators such as IL-1β, TNF-α, iNOS, and IL-6. Neuroinflammation contributes to disease progression in a plethora of neurological disorders ranging from acute CNS trauma to chronic neurodegenerative disease. Posttranscriptional pathways of mRNA stability and translational efficiency are major drivers for the expression of these inflammatory mediators. A common element in this level of regulation centers around the adenine- and uridine-rich element (ARE) which is present in the 3' untranslated region (UTR) of the mRNAs encoding these inflammatory mediators. (ARE)-binding proteins (AUBPs) such as Human antigen R (HuR), Tristetraprolin (TTP) and KH- type splicing regulatory protein (KSRP) are key nodes for directing these posttranscriptional pathways and either promote (HuR) or suppress (TTP and KSRP) glial production of inflammatory mediators. This review will discuss basic concepts of ARE-mediated RNA regulation and its impact on glial-driven neuroinflammatory diseases. We will discuss strategies to target this novel level of gene regulation for therapeutic effect and review exciting preliminary studies that underscore its potential for treating neurological disorders.
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Affiliation(s)
- Abhishek Guha
- Department Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Mohammed Amir Husain
- Department Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Ying Si
- Department Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, USA.,Department Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - L Burt Nabors
- Department Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Natalia Filippova
- Department Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Grace Promer
- Department Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Reed Smith
- Department Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Peter H King
- Department Neurology, The University of Alabama at Birmingham, Birmingham, Alabama, USA.,Department Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA.,Birmingham Department of Veterans Health Care System, Birmingham, Alabama, USA.,Center for Neurodegeneration and Experimental Therapeutics, The University of Alabama at Birmingham, Birmingham, USA
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2
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Jamieson-Lucy AH, Kobayashi M, James Aykit Y, Elkouby YM, Escobar-Aguirre M, Vejnar CE, Giraldez AJ, Mullins MC. A proteomics approach identifies novel resident zebrafish Balbiani body proteins Cirbpa and Cirbpb. Dev Biol 2022; 484:1-11. [PMID: 35065906 PMCID: PMC8967276 DOI: 10.1016/j.ydbio.2022.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 01/11/2022] [Accepted: 01/13/2022] [Indexed: 01/17/2023]
Abstract
The Balbiani body (Bb) is the first marker of polarity in vertebrate oocytes. The Bb is a conserved structure found in diverse animals including insects, fish, amphibians, and mammals. During early zebrafish oogenesis, the Bb assembles as a transient aggregate of mRNA, proteins, and membrane-bound organelles at the presumptive vegetal side of the oocyte. As the early oocyte develops, the Bb appears to grow slowly, until at the end of stage I of oogenesis it disassembles and deposits its cargo of localized mRNAs and proteins. In fish and frogs, this cargo includes the germ plasm as well as gene products required to specify dorsal tissues of the future embryo. We demonstrate that the Bb is a stable, solid structure that forms a size exclusion barrier similar to other biological hydrogels. Despite its central role in oocyte polarity, little is known about the mechanism behind the Bb's action. Analysis of the few known protein components of the Bb is insufficient to explain how the Bb assembles, translocates, and disassembles. We isolated Bbs from zebrafish oocytes and performed mass spectrometry to define the Bb proteome. We successfully identified 77 proteins associated with the Bb sample, including known Bb proteins and novel RNA-binding proteins. In particular, we identified Cirbpa and Cirbpb, which have both an RNA-binding domain and a predicted self-aggregation domain. In stage I oocytes, Cirbpa and Cirbpb localize to the Bb rather than the nucleus (as in somatic cells), indicating that they may have a specialized function in the germ line. Both the RNA-binding domain and the self-aggregation domain are sufficient to localize to the Bb, suggesting that Cirbpa and Cirbpb interact with more than just their mRNA targets within the Bb. We propose that Cirbp proteins crosslink mRNA cargo and proteinaceous components of the Bb as it grows. Beyond Cirbpa and Cirbpb, our proteomics dataset presents many candidates for further study, making it a valuable resource for building a comprehensive mechanism for Bb function at a protein level.
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Affiliation(s)
- Allison H Jamieson-Lucy
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Manami Kobayashi
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Y James Aykit
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Yaniv M Elkouby
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Matias Escobar-Aguirre
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Charles E Vejnar
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Antonio J Giraldez
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Mary C Mullins
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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3
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Chen J, Bassot A, Giuliani F, Simmen T. Amyotrophic Lateral Sclerosis (ALS): Stressed by Dysfunctional Mitochondria-Endoplasmic Reticulum Contacts (MERCs). Cells 2021; 10:cells10071789. [PMID: 34359958 PMCID: PMC8304209 DOI: 10.3390/cells10071789] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/12/2021] [Accepted: 07/13/2021] [Indexed: 02/06/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease for which there is currently no cure. Progress in the characterization of other neurodegenerative mechanisms has shifted the spotlight onto an intracellular structure called mitochondria-endoplasmic reticulum (ER) contacts (MERCs) whose ER portion can be biochemically isolated as mitochondria-associated membranes (MAMs). Within the central nervous system (CNS), these structures control the metabolic output of mitochondria and keep sources of oxidative stress in check via autophagy. The most relevant MERC controllers in the ALS pathogenesis are vesicle-associated membrane protein-associated protein B (VAPB), a mitochondria-ER tether, and the ubiquitin-specific chaperone valosin containing protein (VCP). These two systems cooperate to maintain mitochondrial energy output and prevent oxidative stress. In ALS, mutant VAPB and VCP take a central position in the pathology through MERC dysfunction that ultimately alters or compromises mitochondrial bioenergetics. Intriguingly, both proteins are targets themselves of other ALS mutant proteins, including C9orf72, FUS, or TDP-43. Thus, a new picture emerges, where different triggers cause MERC dysfunction in ALS, subsequently leading to well-known pathological changes including endoplasmic reticulum (ER) stress, inflammation, and motor neuron death.
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Affiliation(s)
- Junsheng Chen
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G2H7, Canada; (J.C.); (A.B.)
| | - Arthur Bassot
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G2H7, Canada; (J.C.); (A.B.)
| | - Fabrizio Giuliani
- Department of Medicine (Neurology), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G2H7, Canada;
| | - Thomas Simmen
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G2H7, Canada; (J.C.); (A.B.)
- Correspondence: ; Tel.: +1-780-492-1546
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4
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Buratti E. Trends in Understanding the Pathological Roles of TDP-43 and FUS Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1281:243-267. [PMID: 33433879 DOI: 10.1007/978-3-030-51140-1_15] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Following the discovery of TDP-43 and FUS involvement in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar dementia (FTLD), the major challenge in the field has been to understand their physiological functions, both in normal and disease conditions. The hope is that this knowledge will improve our understanding of disease and lead to the development of effective therapeutic options. Initially, the focus has been directed at characterizing the role of these proteins in the control of RNA metabolism, because the main function of TDP-43 and FUS is to bind coding and noncoding RNAs to regulate their life cycle within cells. As a result, we now have an in-depth picture of the alterations that occur in RNA metabolism following their aggregation in various ALS/FTLD models and, to a somewhat lesser extent, in patients' brains. In parallel, progress has been made with regard to understanding how aggregation of these proteins occurs in neurons, how it can spread in different brain regions, and how these changes affect various metabolic cellular pathways to result in neuronal death. The aim of this chapter will be to provide a general overview of the trending topics in TDP-43 and FUS investigations and to highlight what might represent the most promising avenues of research in the years to come.
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Affiliation(s)
- Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.
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5
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Chen H, Kankel MW, Su SC, Han SWS, Ofengeim D. Exploring the genetics and non-cell autonomous mechanisms underlying ALS/FTLD. Cell Death Differ 2018; 25:648-662. [PMID: 29459769 DOI: 10.1038/s41418-018-0060-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 12/11/2022] Open
Abstract
Although amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, was first described in 1874, a flurry of genetic discoveries in the last 10 years has markedly increased our understanding of this disease. These findings have not only enhanced our knowledge of mechanisms leading to ALS, but also have revealed that ALS shares many genetic causes with another neurodegenerative disease, frontotemporal lobar dementia (FTLD). In this review, we survey how recent genetic studies have bridged our mechanistic understanding of these two related diseases and how the genetics behind ALS and FTLD point to complex disorders, implicating non-neuronal cell types in disease pathophysiology. The involvement of non-neuronal cell types is consistent with a non-cell autonomous component in these diseases. This is further supported by studies that identified a critical role of immune-associated genes within ALS/FTLD and other neurodegenerative disorders. The molecular functions of these genes support an emerging concept that various non-autonomous functions are involved in neurodegeneration. Further insights into such a mechanism(s) will ultimately lead to a better understanding of potential routes of therapeutic intervention. Facts ALS and FTLD are severe neurodegenerative disorders on the same disease spectrum. Multiple cellular processes including dysregulation of RNA homeostasis, imbalance of proteostasis, contribute to ALS/FTLD pathogenesis. Aberrant function in non-neuronal cell types, including microglia, contributes to ALS/FTLD. Strong neuroimmune and neuroinflammatory components are associated with ALS/FTLD patients. Open Questions Why can patients with similar mutations have different disease manifestations, i.e., why do C9ORF72 mutations lead to motor neuron loss in some patients while others exhibit loss of neurons in the frontotemporal lobe? Do ALS causal mutations result in microglial dysfunction and contribute to ALS/FTLD pathology? How do microglia normally act to mitigate neurodegeneration in ALS/FTLD? To what extent do cellular signaling pathways mediate non-cell autonomous communications between distinct central nervous system (CNS) cell types during disease? Is it possible to therapeutically target specific cell types in the CNS?
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Affiliation(s)
- Hongbo Chen
- Department of Pediatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.,Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA, 02115, USA
| | - Mark W Kankel
- Biogen Inc., 225 Binney Street, Cambridge, MA, 02142, USA
| | - Susan C Su
- Biogen Inc., 225 Binney Street, Cambridge, MA, 02142, USA
| | - Steve W S Han
- Biogen Inc., 225 Binney Street, Cambridge, MA, 02142, USA.,Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.,GSK, Upper Providence, PA, 19426, USA
| | - Dimitry Ofengeim
- Biogen Inc., 225 Binney Street, Cambridge, MA, 02142, USA. .,Sanofi Neuroscience, Framingham, MA, USA.
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6
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The Emerging Role of the Major Histocompatibility Complex Class I in Amyotrophic Lateral Sclerosis. Int J Mol Sci 2017; 18:ijms18112298. [PMID: 29104236 PMCID: PMC5713268 DOI: 10.3390/ijms18112298] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 10/16/2017] [Accepted: 10/26/2017] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting upper and lower motoneurons (MNs). The etiology of the disease is still unknown for most patients with sporadic ALS, while in 5–10% of the familial cases, several gene mutations have been linked to the disease. Mutations in the gene encoding Cu, Zn superoxide dismutase (SOD1), reproducing in animal models a pathological scenario similar to that found in ALS patients, have allowed for the identification of mechanisms relevant to the ALS pathogenesis. Among them, neuroinflammation mediated by glial cells and systemic immune activation play a key role in the progression of the disease, through mechanisms that can be either neuroprotective or neurodetrimental depending on the type of cells and the MN compartment involved. In this review, we will examine and discuss the involvement of major histocompatibility complex class I (MHCI) in ALS concerning its function in the adaptive immunity and its role in modulating the neural plasticity in the central and peripheral nervous system. The evidence indicates that the overexpression of MHCI into MNs protect them from astrocytes’ toxicity in the central nervous system (CNS) and promote the removal of degenerating motor axons accelerating collateral reinnervation of muscles.
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7
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Kong HE, Zhao J, Xu S, Jin P, Jin Y. Fragile X-Associated Tremor/Ataxia Syndrome: From Molecular Pathogenesis to Development of Therapeutics. Front Cell Neurosci 2017; 11:128. [PMID: 28529475 PMCID: PMC5418347 DOI: 10.3389/fncel.2017.00128] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/18/2017] [Indexed: 12/31/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder caused by a premutation CGG repeat expansion (55-200 repeats) within the 5' UTR of the fragile X gene (FMR1). FXTAS is characterized by intension tremor, cerebellar ataxia, progressive neurodegeneration, parkinsonism and cognitive decline. The development of transgenic mouse and Drosophila melanogaster models carrying an expanded CGG repeat has yielded valuable insight into the pathophysiology of FXTAS. To date, we know of two main molecular mechanisms of this disorder: (1) a toxic gain of function of the expanded CGG-repeat FMR1 mRNA, which results in the binding/sequestration of the CGG-binding proteins; and (2) CGG repeat-associated non-AUG-initiated (RAN) translation, which generates a polyglycine peptide toxic to cells. Besides these CGG-mediated mechanisms, recent studies have shed light on additional mechanisms of pathogenesis, such as the antisense transcript ASFMR1, mitochondrial dysfunction, DNA damage from R-loop formation and 5-hydroxymethylcytosine (5hmC)-mediated epigenetic modulation. Here we summarize the recent progress towards understanding the etiology of FXTAS and provide an overview of potential treatment strategies.
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Affiliation(s)
- Ha Eun Kong
- Department of Human Genetics, School of Medicine, Emory UniversityAtlanta, GA, USA
| | - Juan Zhao
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South UniversityChangsha, China
| | - Shunliang Xu
- Department of Neurology, 2nd Hospital of Shandong UniversityJinan, China
| | - Peng Jin
- Department of Human Genetics, School of Medicine, Emory UniversityAtlanta, GA, USA
| | - Yan Jin
- Department of Ophthalmology, Second Hospital, Jilin UniversityChangchun, China
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8
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Abstract
Frontotemporal dementia (FTD) is a heterogeneous disorder with distinct clinical phenotypes associated with multiple neuropathologic entities. Presently, the term FTD encompasses clinical disorders that include changes in behavior, language, executive control, and often motor symptoms. The core FTD spectrum disorders include behavioral variant FTD, nonfluent/agrammatic variant primary progressive aphasia, and semantic variant PPA. Related FTD disorders include frontotemporal dementia with motor neuron disease, progressive supranuclear palsy syndrome, and corticobasal syndrome. In this article, the authors discuss the clinical presentation, diagnostic criteria, neuropathology, genetics, and treatments of these disorders.
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Affiliation(s)
- Nicholas T Olney
- Department of Neurology, UCSF Memory and Aging Center, San Francisco, CA, USA.
| | - Salvatore Spina
- Department of Neurology, UCSF Memory and Aging Center, San Francisco, CA, USA
| | - Bruce L Miller
- Department of Neurology, UCSF Memory and Aging Center, San Francisco, CA, USA; UCSF School of Medicine, San Francisco, CA, USA
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9
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Jun MH, Ryu HH, Jun YW, Liu T, Li Y, Lim CS, Lee YS, Kaang BK, Jang DJ, Lee JA. Sequestration of PRMT1 and Nd1-L mRNA into ALS-linked FUS mutant R521C-positive aggregates contributes to neurite degeneration upon oxidative stress. Sci Rep 2017; 7:40474. [PMID: 28094300 PMCID: PMC5240339 DOI: 10.1038/srep40474] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 12/06/2016] [Indexed: 12/16/2022] Open
Abstract
Mutations in fused in sarcoma (FUS), a DNA/RNA binding protein, are associated with familial amyotrophic lateral sclerosis (ALS). However, little is known about how ALS-causing mutations alter protein-protein and protein-RNA complexes and contribute to neurodegeneration. In this study, we identified protein arginine methyltransferase 1 (PRMT1) as a protein that more avidly associates with ALS-linked FUS-R521C than with FUS-WT (wild type) or FUS-P525L using co-immunoprecipitation and LC-MS analysis. Abnormal association between FUS-R521C and PRMT1 requires RNA, but not methyltransferase activity. PRMT1 was sequestered into cytosolic FUS-R521C-positive stress granule aggregates. Overexpression of PRMT1 rescued neurite degeneration caused by FUS-R521C upon oxidative stress, while loss of PRMT1 further accumulated FUS-positive aggregates and enhanced neurite degeneration. Furthermore, the mRNA of Nd1-L, an actin-stabilizing protein, was sequestered into the FUS-R521C/PRMT1 complex. Nd1-L overexpression rescued neurite shortening caused by FUS-R521C upon oxidative stress, while loss of Nd1-L further exacerbated neurite shortening. Altogether, these data suggest that the abnormal stable complex of FUS-R521C/PRMT1/Nd1-L mRNA could contribute to neurodegeneration upon oxidative stress. Overall, our study provides a novel pathogenic mechanism of the FUS mutation associated with abnormal protein-RNA complexes upon oxidative stress in ALS and provides insight into possible therapeutic targets for this pathology.
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Affiliation(s)
- Mi-Hee Jun
- Department of Biotechnology, College of Life Science and Nanotechnology, Hannam University, Daejeon 34053, South Korea
| | - Hyun-Hee Ryu
- Department of Biotechnology, College of Life Science and Nanotechnology, Hannam University, Daejeon 34053, South Korea
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, South Korea
- Department of Life Science, Chung-Ang University, Seoul, 06974, South Korea
| | - Yong-Woo Jun
- Department of Applied Biology, College of Ecology and Environmental Science, Kyungpook National University, Sangju 37224, South Korea
| | - Tongtong Liu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yan Li
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Chae-Seok Lim
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea
| | - Yong-Seok Lee
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, South Korea
| | - Bong-Kiun Kaang
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, South Korea
| | - Deok-Jin Jang
- Department of Applied Biology, College of Ecology and Environmental Science, Kyungpook National University, Sangju 37224, South Korea
| | - Jin-A Lee
- Department of Biotechnology, College of Life Science and Nanotechnology, Hannam University, Daejeon 34053, South Korea
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10
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Ratti A, Buratti E. Physiological functions and pathobiology of TDP-43 and FUS/TLS proteins. J Neurochem 2016; 138 Suppl 1:95-111. [PMID: 27015757 DOI: 10.1111/jnc.13625] [Citation(s) in RCA: 252] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/19/2016] [Accepted: 03/22/2016] [Indexed: 12/12/2022]
Abstract
The multiple roles played by RNA binding proteins in neurodegeneration have become apparent following the discovery of TAR DNA binding protein 43 kDa (TDP-43) and fused in sarcoma/translocated in liposarcoma (FUS/TLS) involvement in amyotrophic lateral sclerosis and frontotemporal lobar dementia. In these two diseases, the majority of patients display the presence of aggregated forms of one of these proteins in their brains. The study of their functional properties currently represents a very promising target for developing the effective therapeutic options that are still lacking. This aim, however, must be preceded by an accurate evaluation of TDP-43 and FUS/TLS biological functions, both in physiological and disease conditions. Recent findings have uncovered several aspects of RNA metabolism that can be affected by misregulation of these two proteins. Progress has also been made in starting to understand how the aggregation of these proteins occurs and spreads from cell to cell. The aim of this review will be to provide a general overview of TDP-43 and FUS/TLS proteins and to highlight their physiological functions. At present, the emerging picture is that TDP-43 and FUS/TLS control several aspects of an mRNA's life, but they can also participate in DNA repair processes and in non-coding RNA metabolism. Although their regulatory activities are similar, they regulate mainly distinct RNA targets and show different pathogenetic mechanisms in amyotrophic lateral sclerosis/frontotemporal lobar dementia diseases. The identification of key events in these processes represents today the best chance of finding targetable options for therapeutic approaches that might actually make a difference at the clinical level. The two major RNA Binding Proteins involved in Amyotrophic Lateral Sclerosisi and Frontotemporal Dementia are TDP-43 and FUST/TLS. Both proteins are involved in regulating all aspects of RNA and RNA life cycle within neurons, from transcription, processing, and transport/stability to the formation of cytoplasmic and nuclear stress granules. For this reason, the aberrant aggregation of these factors during disease can impair multiple RNA metabolic pathways and eventually lead to neuronal death/inactivation. The purpose of this review is to provide an up-to-date perspective on what we know about this issue at the molecular level. This article is part of the Frontotemporal Dementia special issue.
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Affiliation(s)
- Antonia Ratti
- Department of Pathophysiology and Transplantation, 'Dino Ferrari' Center - Università degli Studi di Milano, Milan, Italy.,Department of Neurology and Laboratory of Neuroscience, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
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11
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Hyperactive somatostatin interneurons contribute to excitotoxicity in neurodegenerative disorders. Nat Neurosci 2016; 19:557-559. [PMID: 26900927 PMCID: PMC4811704 DOI: 10.1038/nn.4257] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/27/2016] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are overlapping neurodegenerative disorders whose pathogenesis remains largely unknown. Here using TDP-43A315T mice, an ALS and FTD model with profound cortical pathology, we demonstrated that hyperactive somatostatin interneurons disinhibited layer 5 pyramidal neurons (L5-PN) and contributed to their excitotoxicity. Focal ablation of somatostatin interneurons efficiently restored normal excitability of L5-PN and alleviated neurodegeneration, suggesting a novel therapeutic target for ALS and FTD.
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12
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Abstract
Amyotrophic lateral sclerosis (ALS), also called Lou Gehrig's disease, is a fatal neuromuscular disorder characterized by degeneration of motor neurons and by skeletal muscle atrophy. Although the death of motor neurons is a pathological hallmark of ALS, the potential role of other organs in disease progression remains to be elucidated. Skeletal muscle and bone are the two largest organs in the human body. They are responsible not only for locomotion but also for maintaining whole body normal metabolism and homeostasis. Patients with ALS display severe muscle atrophy, which may reflect intrinsic defects in mitochondrial respiratory function and calcium (Ca) signaling in muscle fibers, in addition to the role of axonal withdrawal associated with ALS progression. Incidence of fractures is high in ALS patients, indicating there are potential bone defects in individuals with this condition. There is a lifelong interaction between skeletal muscle and bone. The severe muscle degeneration that occurs during ALS progression may potentially have a significant impact on bone function, and the defective bone may also contribute significantly to neuromuscular degeneration in the course of the disease. Due to the nature of the rapid and severe neuromuscular symptoms, a majority of studies on ALS have focused on neurodegeneration. Just a few studies have explored the possible contribution of muscle defects, even fewer on bone defects, and fewer still on possible muscle-bone crosstalk in ALS. This review article discusses current studies on bone defects and potential defects in muscle-bone crosstalk in ALS.
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Affiliation(s)
- Jingsong Zhou
- Department of Physiology, Kansas City University of Medicine and Biosciences, 1750 Independence Ave., Kansas City, MO, 64106, USA,
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13
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Lourenco GF, Janitz M, Huang Y, Halliday GM. Long noncoding RNAs in TDP-43 and FUS/TLS-related frontotemporal lobar degeneration (FTLD). Neurobiol Dis 2015. [DOI: 10.1016/j.nbd.2015.07.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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14
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Deng J, Yang M, Chen Y, Chen X, Liu J, Sun S, Cheng H, Li Y, Bigio EH, Mesulam M, Xu Q, Du S, Fushimi K, Zhu L, Wu JY. FUS Interacts with HSP60 to Promote Mitochondrial Damage. PLoS Genet 2015; 11:e1005357. [PMID: 26335776 PMCID: PMC4559378 DOI: 10.1371/journal.pgen.1005357] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/12/2015] [Indexed: 12/13/2022] Open
Abstract
FUS-proteinopathies, a group of heterogeneous disorders including ALS-FUS and FTLD-FUS, are characterized by the formation of inclusion bodies containing the nuclear protein FUS in the affected patients. However, the underlying molecular and cellular defects remain unclear. Here we provide evidence for mitochondrial localization of FUS and its induction of mitochondrial damage. Remarkably, FTLD-FUS brain samples show increased FUS expression and mitochondrial defects. Biochemical and genetic data demonstrate that FUS interacts with a mitochondrial chaperonin, HSP60, and that FUS translocation to mitochondria is, at least in part, mediated by HSP60. Down-regulating HSP60 reduces mitochondrially localized FUS and partially rescues mitochondrial defects and neurodegenerative phenotypes caused by FUS expression in transgenic flies. This is the first report of direct mitochondrial targeting by a nuclear protein associated with neurodegeneration, suggesting that mitochondrial impairment may represent a critical event in different forms of FUS-proteinopathies and a common pathological feature for both ALS-FUS and FTLD-FUS. Our study offers a potential explanation for the highly heterogeneous nature and complex genetic presentation of different forms of FUS-proteinopathies. Our data also suggest that mitochondrial damage may be a target in future development of diagnostic and therapeutic tools for FUS-proteinopathies, a group of devastating neurodegenerative diseases. Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) are two groups of common and devastating neurodegenerative diseases, characterized by losses of selected groups of neurons. Mutations in the FUS gene have been associated with ALS, whereas inclusion bodies containing the FUS protein have been discovered in both ALS and FTLD patients. However, the underlying pathogenic mechanisms of FUS in these diseases remain unclear. Here, we demonstrate that wild-type or ALS-associated mutant FUS can interact with mitochondrial chaperonin HSP60 and that HSP60 mediates FUS localization to mitochondria, leading to mitochondrial damage. Mitochondrial impairment may be an early event in FUS proteinopathies and represent a potential therapeutic target for treating these fatal diseases.
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Affiliation(s)
- Jianwen Deng
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Mengxue Yang
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Department of Neurology, Center for Genetic Medicine, Lurie Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Yanbo Chen
- Department of Neurology, Center for Genetic Medicine, Lurie Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Science and Peking Union Medical College, Tsinghua University, Beijing, China
| | - Xiaoping Chen
- Department of Neurology, Center for Genetic Medicine, Lurie Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Jianghong Liu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Shufeng Sun
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Haipeng Cheng
- Department of Neurology, Center for Genetic Medicine, Lurie Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Yang Li
- Department of Neurology, Center for Genetic Medicine, Lurie Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
| | - Eileen H. Bigio
- Department of Pathology & Neurology, The Cognitive Neurology& Alzheimer's Disease Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Marsel Mesulam
- Department of Pathology & Neurology, The Cognitive Neurology& Alzheimer's Disease Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Qi Xu
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Science and Peking Union Medical College, Tsinghua University, Beijing, China
| | - Sidan Du
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
| | - Kazuo Fushimi
- Department of Neurology, Center for Genetic Medicine, Lurie Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Li Zhu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- * E-mail: (LZ); (JYW)
| | - Jane Y. Wu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- Department of Neurology, Center for Genetic Medicine, Lurie Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
- * E-mail: (LZ); (JYW)
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15
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Schachtner LT, Sola IE, Forand D, Antonacci S, Postovit AJ, Mortimer NT, Killian DJ, Olesnicky EC. Drosophila Shep and C. elegans SUP-26 are RNA-binding proteins that play diverse roles in nervous system development. Dev Genes Evol 2015; 225:319-30. [PMID: 26271810 DOI: 10.1007/s00427-015-0514-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 08/03/2015] [Indexed: 12/14/2022]
Abstract
The Caenorhabditis elegans gene sup-26 encodes a well-conserved RNA-recognition motif-containing RNA-binding protein (RBP) that functions in dendrite morphogenesis of the PVD sensory neuron. The Drosophila ortholog of sup-26, alan shepard (shep), is expressed throughout the nervous system and has been shown to regulate neuronal remodeling during metamorphosis. Here, we extend these studies to show that sup-26 and shep are required for the development of diverse cell types within the nematode and fly nervous systems during embryonic and larval stages. We ascribe roles for sup-26 in regulating dendrite number and the expression of genes involved in mechanosensation within the nematode peripheral nervous system. We also find that in Drosophila, shep regulates dendrite length and branch order of nociceptive neurons, regulates the organization of neuronal clusters of the peripheral nervous system and the organization of axons within the ventral nerve cord. Taken together, our results suggest that shep/sup-26 orthologs play diverse roles in neural development across animal species. Moreover, we discuss potential roles for shep/sup-26 orthologs in the human nervous system.
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Affiliation(s)
- Logan T Schachtner
- Department of Biology, University of Colorado at Colorado Springs, 1420 Austin Bluffs Parkway, Colorado Springs, CO, 80918, USA
| | - Ismail E Sola
- Department of Biology, University of Colorado at Colorado Springs, 1420 Austin Bluffs Parkway, Colorado Springs, CO, 80918, USA
| | - Daniel Forand
- Department of Biology, University of Colorado at Colorado Springs, 1420 Austin Bluffs Parkway, Colorado Springs, CO, 80918, USA
| | - Simona Antonacci
- Department of Molecular Biology, Colorado College, 14 East Cache La Poudre Street, Colorado Springs, CO, 80903, USA
| | - Adam J Postovit
- Department of Biology, University of Colorado at Colorado Springs, 1420 Austin Bluffs Parkway, Colorado Springs, CO, 80918, USA
| | - Nathan T Mortimer
- Department of Biological Sciences, University of Denver, Denver, CO, 80208, USA.,School of Biological Sciences, Illinois State University, Normal, IL, 61790, USA
| | - Darrell J Killian
- Department of Molecular Biology, Colorado College, 14 East Cache La Poudre Street, Colorado Springs, CO, 80903, USA.
| | - Eugenia C Olesnicky
- Department of Biology, University of Colorado at Colorado Springs, 1420 Austin Bluffs Parkway, Colorado Springs, CO, 80918, USA.
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16
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Szafranski K, Abraham KJ, Mekhail K. Non-coding RNA in neural function, disease, and aging. Front Genet 2015; 6:87. [PMID: 25806046 PMCID: PMC4353379 DOI: 10.3389/fgene.2015.00087] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 02/18/2015] [Indexed: 12/03/2022] Open
Abstract
Declining brain and neurobiological function is arguably one of the most common features of human aging. The study of conserved aging processes as well as the characterization of various neurodegenerative diseases using different genetic models such as yeast, fly, mouse, and human systems is uncovering links to non-coding RNAs. These links implicate a variety of RNA-regulatory processes, including microRNA function, paraspeckle formation, RNA–DNA hybrid regulation, nucleolar RNAs and toxic RNA clearance, amongst others. Here we highlight these connections and reveal over-arching themes or questions related to recently appreciated roles of non-coding RNA in neural function and dysfunction across lifespan.
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Affiliation(s)
- Kirk Szafranski
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - Karan J Abraham
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - Karim Mekhail
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto Toronto, ON, Canada ; Canada Research Chairs Program, Faculty of Medicine, University of Toronto Toronto, ON, Canada
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17
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Galloway JN, Shaw C, Yu P, Parghi D, Poidevin M, Jin P, Nelson DL. CGG repeats in RNA modulate expression of TDP-43 in mouse and fly models of fragile X tremor ataxia syndrome. Hum Mol Genet 2014; 23:5906-15. [PMID: 24986919 DOI: 10.1093/hmg/ddu314] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Determining the molecular mechanism(s) leading to Purkinje neuron loss in the neurodegenerative disorder fragile X-associated tremor/ataxia syndrome (FXTAS) is limited by the complex morphology of this cell type. Purkinje neurons are notoriously difficult to isolate and maintain in culture presenting considerable difficultly to identify molecular changes in response to expanded CGG repeat (rCGG)-containing mRNA that induces neurotoxicity in FXTAS. Several studies have uncovered a number of RNA-binding proteins involved in translation that aberrantly interact with the CGG-containing RNA; however, whether these interactions alter the translational profile of cells has not been investigated. Here we employ bacTRAP translational profiling to demonstrate that Purkinje neurons ectopically expressing 90 CGG repeats exhibit a dramatic change in their translational profile even prior to the onset of rCGG-induced phenotypes. This approach identified ∼500 transcripts that are differentially associated with ribosomes in r(CGG)₉₀-expressing mice. Functional annotation cluster analysis revealed broad ontologies enriched in the r(CGG)₉₀ list, including RNA binding and response to stress. Intriguingly, a transcript for the Tardbp gene, implicated in a number of other neurodegenerative disorders, exhibits altered association with ribosomes in the presence of r(CGG)₉₀ repeats. We therefore tested and showed that reduced association of Tardbp mRNA with the ribosomes results in a loss of TDP-43 protein expression in r(CGG)₉₀-expressing Purkinje neurons. Furthermore, we showed that TDP-43 could modulate the rCGG repeat-mediated toxicity in a Drosophila model that we developed previously. These findings together suggest that translational dysregulation may be an underlying mechanism of rCGG-induced neurotoxicity in FXTAS.
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Affiliation(s)
| | - Chad Shaw
- Department of Human and Molecular Genetics and
| | - Peng Yu
- Department of Human and Molecular Genetics and
| | - Deena Parghi
- Department of Pathology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA and
| | - Mickael Poidevin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Peng Jin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - David L Nelson
- Interdepartmental Program in Cell and Molecular Biology, Department of Human and Molecular Genetics and
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18
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Honda D, Ishigaki S, Iguchi Y, Fujioka Y, Udagawa T, Masuda A, Ohno K, Katsuno M, Sobue G. The ALS/FTLD-related RNA-binding proteins TDP-43 and FUS have common downstream RNA targets in cortical neurons. FEBS Open Bio 2013; 4:1-10. [PMID: 24319651 PMCID: PMC3851184 DOI: 10.1016/j.fob.2013.11.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 11/11/2013] [Accepted: 11/11/2013] [Indexed: 12/12/2022] Open
Abstract
TDP-43 and FUS are linked to amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), and loss of function of either protein contributes to these neurodegenerative conditions. To elucidate the TDP-43- and FUS-regulated pathophysiological RNA metabolism cascades, we assessed the differential gene expression and alternative splicing profiles related to regulation by either TDP-43 or FUS in primary cortical neurons. These profiles overlapped by >25% with respect to gene expression and >9% with respect to alternative splicing. The shared downstream RNA targets of TDP-43 and FUS may form a common pathway in the neurodegenerative processes of ALS/FTLD.
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Key Words
- ALS
- ALS, amyotrophic lateral sclerosis
- Cugbp1, CUG triplet repeat, RNA-binding protein 1
- DAVID, Database for Annotation, Visualization and Integrated Discovery
- FTLD
- FTLD, frontotemporal lobar degeneration
- FUS
- FUS, fused in sarcoma
- GFAP, glial fibrillary acidic protein
- GO, Gene Ontology
- LTP, long-term potentiation
- RIN, RNA integrity numbers
- RMA, robust multichip average
- RRMs, RNA recognition motifs
- SBMA, spinal and bulbar muscular atrophy
- TDP-43
- TDP-43, transactive response (TAR) DNA-binding protein 43
- TGF, transforming growth factor
- Transcriptome
- hnRNAPs, heterogeneous ribonucleoproteins
- shCont, shRNA/control
- shCugbp1, shRNA/Cugbp1
- shFUS, shRNA/FUS
- shTDP, shRNA/TDP-43
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Affiliation(s)
- Daiyu Honda
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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19
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Shelkovnikova TA, Robinson HK, Connor-Robson N, Buchman VL. Recruitment into stress granules prevents irreversible aggregation of FUS protein mislocalized to the cytoplasm. Cell Cycle 2013; 12:3194-202. [PMID: 24013423 PMCID: PMC3865015 DOI: 10.4161/cc.26241] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Fused in sarcoma (FUS) belongs to the group of RNA-binding proteins implicated as underlying factors in amyotrophic lateral sclerosis (ALS) and certain other neurodegenerative diseases. Multiple FUS gene mutations have been linked to hereditary forms, and aggregation of FUS protein is believed to play an important role in pathogenesis of these diseases. In cultured cells, FUS variants with disease-associated amino acid substitutions or short deletions affecting nuclear localization signal (NLS) and causing cytoplasmic mislocalization can be sequestered into stress granules (SGs). We demonstrated that disruption of motifs responsible for RNA recognition and binding not only prevents SG recruitment, but also dramatically increases the protein propensity to aggregate in the cell cytoplasm with formation of juxtanuclear structures displaying typical features of aggresomes. Functional RNA-binding domains from TAR DNA-binding protein of 43 kDa (TDP-43) fused to highly aggregation-prone C-terminally truncated FUS protein restored the ability to enter SGs and prevented aggregation of the chimeric protein. Truncated FUS was also able to trap endogenous FUS molecules in the cytoplasmic aggregates. Our data indicate that RNA binding and recruitment to SGs protect cytoplasmic FUS from aggregation, and loss of this protection may trigger its pathological aggregation in vivo.
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Affiliation(s)
- Tatyana A Shelkovnikova
- School of Biosciences; Cardiff University; Cardiff, UK; Institute of Physiologically Active Compounds Russian Academy of Sciences; Moscow Region, Russian Federation
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20
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van Blitterswijk M, Baker MC, Bieniek KF, Knopman DS, Josephs KA, Boeve B, Caselli R, Wszolek ZK, Petersen R, Graff-Radford NR, Boylan KB, Dickson DW, Rademakers R. Profilin-1 mutations are rare in patients with amyotrophic lateral sclerosis and frontotemporal dementia. Amyotroph Lateral Scler Frontotemporal Degener 2013; 14:463-9. [PMID: 23634771 PMCID: PMC3923463 DOI: 10.3109/21678421.2013.787630] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mutations in profilin-1 (PFN1) have recently been identified in patients with amyotrophic lateral sclerosis (ALS). Because of the considerable overlap between ALS and the common subtype of frontotemporal dementia, which is characterized by transactive response DNA-binding protein 43 pathology (FTLD-TDP), we tested cohorts of ALS and FTLD-TDP patients for PFN1 mutations. DNA was obtained from 342 ALS patients and 141 FTLD-TDP patients at our outpatient clinic and brain bank for neurodegenerative diseases at the Mayo Clinic Florida, Jacksonville, USA. We screened these patients for mutations in coding regions of PFN1 by Sanger sequencing. Subsequently, we used TaqMan genotyping assays to investigate the identified variant in 1167 control subjects. From the results, one variant, p.E117G, was detected in one ALS patient, one FTLD-TDP patient, and two control subjects. The mutation frequency of patients versus control subjects was not significantly different (p-value = 0.36). Moreover, PFN1 and TDP-43 staining of autopsy material did not differ between patients with or without this variant. In conclusion, the p.E117G variant appears to represent a benign polymorphism. PFN1 mutations, in general, are rare in ALS and FTLD-TDP patients.
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Affiliation(s)
| | | | | | | | | | - Bradley Boeve
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | | | | | | | | | | | | | - Rosa Rademakers
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
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21
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Rieder LE, Staber CJ, Hoopengardner B, Reenan RA. Tertiary structural elements determine the extent and specificity of messenger RNA editing. Nat Commun 2013; 4:2232. [PMID: 23903876 DOI: 10.1038/ncomms3232] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 07/02/2013] [Indexed: 02/03/2023] Open
Abstract
The specificity and extent of RNA editing by ADAR enzymes is determined largely by local primary sequence and secondary structural imperfections in duplex RNA. Here we surgically alter conserved cis elements associated with a cluster of ADAR modification sites within the endogenous Drosophila paralytic transcript. In addition to the local requirement for a central imperfect RNA duplex containing the modified adenosines, we demonstrate that a secondary RNA duplex containing splicing signals strongly modulates RNA editing. A subtle non-coding mutation, extending base pairing of this accessory helix, confers significant phenotypic consequences via effects on splicing. Through mutation/counter-mutation, we also uncover and functionally replace a highly conserved intronic long-range tertiary pseudoknot that is absolutely required for deamination of one particular adenosine in the central duplex. Our results demonstrate that complex RNA tertiary structures, which may be difficult to predict computationally, form in vivo and can regulate RNA-editing events.
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Affiliation(s)
- Leila E Rieder
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, Rhode Island 02912, USA
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22
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Miyazaki K, Yamashita T, Morimoto N, Sato K, Mimoto T, Kurata T, Ikeda Y, Abe K. Early and selective reduction of NOP56 (Asidan) and RNA processing proteins in the motor neuron of ALS model mice. Neurol Res 2013; 35:744-54. [PMID: 23582672 DOI: 10.1179/1743132813y.0000000196] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE There is increasing evidence to support that altered RNA processing is implicated in the pathogenesis of motor neuron degeneration of amyotrophic lateral sclerosis (ALS). We evaluate the expression of three RNA processing-related proteins in ALS model mice in this study. METHODS We analyzed expression and distribution patterns of three RNA processing-related proteins, nucleolar protein (NOP) 56 (identified as causative gene for spinocerebellar ataxia (SCA) 36, nicknamed Asidan), TDP-43, and fused in sarcoma/translocated in liposarcoma (FUS) in lumbar and cervical cords, hypoglossal nucleus, cerebral motor cortex, and cerebellum of transgenic (Tg) SOD1 G93A ALS model mice throughout the course of motor neuron degeneration. RESULTS Compared to age-matched wild type (WT) mice, Tg mice showed progressive reduction of NOP56 levels in the large motor neurons of lumbar and cervical cords from the early-symptomatic stage (14 weeks of age) to the end stage of the disease (18 weeks). TDP-43 and FUS protein levels showed a later decrease in the nucleus of large motor neuron at 18 weeks (end stage of the disease). These changes were not observed in the primary motor cortex of the cerebrum as well as molecular and granular layers and Purkinje cells in the cerebellum. DISCUSSION The present study suggests a progressive loss of these three nuclear proteins and subsequent RNA processing problems including a novel gene relating to ALS (NOP56) under the motor neuron degeneration.
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Affiliation(s)
- Kazunori Miyazaki
- Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science, Shikata-cho, Okayama, Japan
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23
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Bae JS, Simon NG, Menon P, Vucic S, Kiernan MC. The puzzling case of hyperexcitability in amyotrophic lateral sclerosis. J Clin Neurol 2013; 9:65-74. [PMID: 23626643 PMCID: PMC3633193 DOI: 10.3988/jcn.2013.9.2.65] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 08/24/2012] [Accepted: 08/24/2012] [Indexed: 12/11/2022] Open
Abstract
The development of hyperexcitability in amyotrophic lateral sclerosis (ALS) is a well-known phenomenon. Despite controversy as to the underlying mechanisms, cortical hyperexcitability appears to be closely related to the interplay between excitatory corticomotoneurons and inhibitory interneurons. Hyperexcitability is not a static phenomenon but rather shows a pattern of progression in a spatiotemporal aspect. Cortical hyperexcitability may serve as a trigger to the development of anterior horn cell degeneration through a 'dying forward' process. Hyperexcitability appears to develop during the early disease stages and gradually disappears in the advanced stages of the disease, linked to the destruction of corticomotorneuronal pathways. As such, a more precise interpretation of these unique processes may provide new insight regarding the pathophysiology of ALS and its clinical features. Recently developed technologies such as threshold tracking transcranial magnetic stimulation and automated nerve excitability tests have provided some clues about underlying pathophysiological processes linked to hyperexcitability. Additionally, these novel techniques have enabled clinicians to use the specific finding of hyperexcitability as a useful diagnostic biomarker, enabling clarification of various ALS-mimic syndromes, and the prediction of disease development in pre-symptomatic carriers of familial ALS. In terms of nerve excitability tests for peripheral nerves, an increase in persistent Na+ conductances has been identified as a major determinant of peripheral hyperexcitability in ALS, inversely correlated with the survival in ALS. As such, the present Review will focus primarily on the puzzling theory of hyperexcitability in ALS and summarize clinical and pathophysiological implications for current and future ALS research.
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Affiliation(s)
- Jong Seok Bae
- Department of Neurology, College of Medicine, Inje University, Busan, Korea. ; Neuroscience Research Australia, Sydney, Australia
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24
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Shodai A, Morimura T, Ido A, Uchida T, Ayaki T, Takahashi R, Kitazawa S, Suzuki S, Shirouzu M, Kigawa T, Muto Y, Yokoyama S, Takahashi R, Kitahara R, Ito H, Fujiwara N, Urushitani M. Aberrant assembly of RNA recognition motif 1 links to pathogenic conversion of TAR DNA-binding protein of 43 kDa (TDP-43). J Biol Chem 2013; 288:14886-905. [PMID: 23558684 DOI: 10.1074/jbc.m113.451849] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Aggregation of TAR DNA-binding protein of 43 kDa (TDP-43) is a pathological signature of amyotrophic lateral sclerosis (ALS). Although accumulating evidence suggests the involvement of RNA recognition motifs (RRMs) in TDP-43 proteinopathy, it remains unclear how native TDP-43 is converted to pathogenic forms. To elucidate the role of homeostasis of RRM1 structure in ALS pathogenesis, conformations of RRM1 under high pressure were monitored by NMR. We first found that RRM1 was prone to aggregation and had three regions showing stable chemical shifts during misfolding. Moreover, mass spectrometric analysis of aggregated RRM1 revealed that one of the regions was located on protease-resistant β-strands containing two cysteines (Cys-173 and Cys-175), indicating that this region served as a core assembly interface in RRM1 aggregation. Although a fraction of RRM1 aggregates comprised disulfide-bonded oligomers, the substitution of cysteine(s) to serine(s) (C/S) resulted in unexpected acceleration of amyloid fibrils of RRM1 and disulfide-independent aggregate formation of full-length TDP-43. Notably, TDP-43 aggregates with RRM1-C/S required the C terminus, and replicated cytopathologies of ALS, including mislocalization, impaired RNA splicing, ubiquitination, phosphorylation, and motor neuron toxicity. Furthermore, RRM1-C/S accentuated inclusions of familial ALS-linked TDP-43 mutants in the C terminus. The relevance of RRM1-C/S-induced TDP-43 aggregates in ALS pathogenesis was verified by immunolabeling of inclusions of ALS patients and cultured cells overexpressing the RRM1-C/S TDP-43 with antibody targeting misfolding-relevant regions. Our results indicate that cysteines in RRM1 crucially govern the conformation of TDP-43, and aberrant self-assembly of RRM1 at amyloidogenic regions contributes to pathogenic conversion of TDP-43 in ALS.
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Affiliation(s)
- Akemi Shodai
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu 520-2192, Japan
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25
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Tauffenberger A, Chitramuthu BP, Bateman A, Bennett HPJ, Parker JA. Reduction of polyglutamine toxicity by TDP-43, FUS and progranulin in Huntington's disease models. Hum Mol Genet 2012; 22:782-94. [PMID: 23172908 DOI: 10.1093/hmg/dds485] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The DNA/RNA binding proteins TAR DNA-binding protein 43 (TDP-43) and fused-in-sarcoma (FUS) are genetically linked to amyotrophic lateral sclerosis and frontotemporal lobar dementia, while the inappropriate cytoplasmic accumulations of TDP-43 and FUS are observed in a growing number of late-onset pathologies including spinocerebellar ataxia 3, Alzheimer's and Huntington's diseases (HD). To investigate if TDP-43 and FUS contribute to neurodegenerative phenotypes, we turned to a genetically accessible Caenorhabditis elegans model of polyglutamine toxicity. In C. elegans, we observe that genetic loss-of-function mutations for nematode orthologs of TDP-43 or FUS reduced behavioral defects and neurodegeneration caused by huntingtin exon-1 with expanded polyglutamines. Furthermore, using striatal cells from huntingtin knock-in mice we observed that small interfering ribonucleic acid (siRNA) against TDP-43 or FUS reduced cell death caused by mutant huntingtin. Moreover, we found that TDP-43 and the survival factor progranulin (PGRN) genetically interact to regulate polyglutamine toxicity in C. elegans and mammalian cells. Altogether our data point towards a conserved function for TDP-43 and FUS in promoting polyglutamine toxicity and that delivery of PGRN may have therapeutic benefits.
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