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Abstract
Individuals carrying an FMR1 expansion between 55 and 200 CGG repeats, are at risk of developing the Fragile X-associated tremor/ataxia syndrome (FXTAS), a late onset neurodegenerative disorder characterized by cerebellar gait ataxia, intentional tremor, neuropathy, parkinsonism, cognitive decline, and psychological disorders, such as anxiety and depression. In addition, brain atrophy, white matter disease, and hyperintensities of the middle cerebellar peduncles can also be present. The neuropathological distinct feature of FXTAS is represented by the presence of eosinophilic intranuclear inclusions in neurons and astrocytes throughout the brain and in other tissues. In this chapter, protocols for available diagnostic tools, in both humans and mice, the clinical features and the basic molecular mechanisms leading to FXTAS and the animal models proposed to study this disorder are discussed.
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102
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Neueder A. RNA-Mediated Disease Mechanisms in Neurodegenerative Disorders. J Mol Biol 2018; 431:1780-1791. [PMID: 30597161 DOI: 10.1016/j.jmb.2018.12.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 12/14/2018] [Accepted: 12/16/2018] [Indexed: 12/16/2022]
Abstract
RNA is accurately entangled in virtually all pathways that maintain cellular homeostasis. To name but a few, RNA is the "messenger" between DNA encoded information and the resulting proteins. Furthermore, RNAs regulate diverse processes by forming DNA::RNA or RNA::RNA interactions. Finally, RNA itself can be the scaffold for ribonucleoprotein complexes, for example, ribosomes or cellular bodies. Consequently, disruption of any of these processes can lead to disease. This review describes known and emerging RNA-based disease mechanisms like interference with regular splicing, the anomalous appearance of RNA-protein complexes and uncommon RNA species, as well as non-canonical translation. Due to the complexity and entanglement of the above-mentioned pathways, only few drugs are available that target RNA-based disease mechanisms. However, advances in our understanding how RNA is involved in and modulates cellular homeostasis might pave the way to novel treatments.
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Affiliation(s)
- Andreas Neueder
- Experimental Neurology, Department of Neurology, Ulm University, 89081 Ulm, Germany.
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103
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Martínez Cerdeño V, Hong T, Amina S, Lechpammer M, Ariza J, Tassone F, Noctor SC, Hagerman P, Hagerman R. Microglial cell activation and senescence are characteristic of the pathology FXTAS. Mov Disord 2018; 33:1887-1894. [PMID: 30537011 DOI: 10.1002/mds.27553] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/15/2018] [Accepted: 09/27/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder associated with premutation alleles of the FMR1 gene. Expansions of more than 200 CGG repeats give rise to fragile X syndrome, the most common inherited form of cognitive impairment. Fragile X-associated tremor/ataxia syndrome is characterized by cerebellar tremor and ataxia, and the presence of ubiquitin-positive inclusions in neurons and astrocytes. It has been previously suggested that fragile X-associated tremor/ataxia syndrome is associated with an inflammatory state based on signs of oxidative stress-mediated damage and iron deposition. OBJECTIVE Determine whether the pathology of fragile X-associated tremor/ataxia syndrome involves microglial activation and an inflammatory state. METHODS Using ionized calcium binding adaptor molecule 1 and cluster differentiation 68 antibodies to label microglia, we examined the number and state of activation of microglial cells in the putamen of 13 fragile X-associated tremor/ataxia syndrome and 9 control postmortem cases. RESULTS Nearly half of fragile X-associated tremor/ataxia syndrome cases (6 of 13) presented with dystrophic senescent microglial cells. In the remaining fragile X-associated tremor/ataxia syndrome cases (7 of 13), the number of microglial cells and their activation state were increased compared to controls. CONCLUSIONS The presence of senescent microglial cells in half of fragile X-associated tremor/ataxia syndrome cases suggests that this indicator could be used, together with the presence of intranuclear inclusions and the presence of iron deposits, as a biomarker to aid in the postmortem diagnosis of fragile X-associated tremor/ataxia syndrome. An increased number and activation indicate that microglial cells play a role in the inflammatory state present in the fragile X-associated tremor/ataxia syndrome brain. Anti-inflammatory treatment of patients with fragile X-associated tremor/ataxia syndrome may be indicated to slow neurodegeneration. © 2018 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Verónica Martínez Cerdeño
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, California, USA.,Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, Sacramento, California, USA.,MIND Institute, UC Davis Medical Center, Sacramento, California, USA
| | - Tiffany Hong
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, California, USA.,Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, Sacramento, California, USA
| | - Sarwat Amina
- Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, Sacramento, California, USA.,MIND Institute, UC Davis Medical Center, Sacramento, California, USA
| | - Mirna Lechpammer
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, California, USA
| | - Jeanelle Ariza
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, California, USA.,Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, Sacramento, California, USA
| | - Flora Tassone
- MIND Institute, UC Davis Medical Center, Sacramento, California, USA.,Department of Biochemistry and Molecular Medicine, UC Davis School of Medicine Sacramento, California, USA
| | - Stephen C Noctor
- MIND Institute, UC Davis Medical Center, Sacramento, California, USA.,Department of Psychiatry and Behavioral Sciences, UC Davis School of Medicine Sacramento, California, USA
| | - Paul Hagerman
- MIND Institute, UC Davis Medical Center, Sacramento, California, USA.,Department of Biochemistry and Molecular Medicine, UC Davis School of Medicine Sacramento, California, USA
| | - Randi Hagerman
- MIND Institute, UC Davis Medical Center, Sacramento, California, USA.,Department of Pediatrics, UC Davis School of Medicine Sacramento, California, USA
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104
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Sawyer IA, Sturgill D, Dundr M. Membraneless nuclear organelles and the search for phases within phases. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 10:e1514. [DOI: 10.1002/wrna.1514] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/20/2018] [Accepted: 09/27/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Iain A. Sawyer
- Department of Cell Biology and Anatomy, Chicago Medical School Rosalind Franklin University of Medicine and Science North Chicago Illinois
- Laboratory of Receptor Biology and Gene Expression National Cancer Institute, National Institutes of Health Bethesda Maryland
| | - David Sturgill
- Laboratory of Receptor Biology and Gene Expression National Cancer Institute, National Institutes of Health Bethesda Maryland
| | - Miroslav Dundr
- Department of Cell Biology and Anatomy, Chicago Medical School Rosalind Franklin University of Medicine and Science North Chicago Illinois
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105
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Bovaird S, Patel D, Padilla JCA, Lécuyer E. Biological functions, regulatory mechanisms, and disease relevance of RNA localization pathways. FEBS Lett 2018; 592:2948-2972. [PMID: 30132838 DOI: 10.1002/1873-3468.13228] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/06/2018] [Accepted: 08/17/2018] [Indexed: 12/12/2022]
Abstract
The asymmetric subcellular distribution of RNA molecules from their sites of transcription to specific compartments of the cell is an important aspect of post-transcriptional gene regulation. This involves the interplay of intrinsic cis-regulatory elements within the RNA molecules with trans-acting RNA-binding proteins and associated factors. Together, these interactions dictate the intracellular localization route of RNAs, whose downstream impacts have wide-ranging implications in cellular physiology. In this review, we examine the mechanisms underlying RNA localization and discuss their biological significance. We also review the growing body of evidence pointing to aberrant RNA localization pathways in the development and progression of diseases.
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Affiliation(s)
- Samantha Bovaird
- Institut de recherches cliniques de Montréal (IRCM), QC, Canada.,Division of Experimental Medicine, Faculty of Medicine, McGill University, Montreal, QC, Canada
| | - Dhara Patel
- Institut de recherches cliniques de Montréal (IRCM), QC, Canada.,Molecular Biology Program, Faculty of Medicine, Université de Montréal, QC, Canada
| | - Juan-Carlos Alberto Padilla
- Institut de recherches cliniques de Montréal (IRCM), QC, Canada.,Division of Experimental Medicine, Faculty of Medicine, McGill University, Montreal, QC, Canada
| | - Eric Lécuyer
- Institut de recherches cliniques de Montréal (IRCM), QC, Canada.,Division of Experimental Medicine, Faculty of Medicine, McGill University, Montreal, QC, Canada.,Molecular Biology Program, Faculty of Medicine, Université de Montréal, QC, Canada.,Department of Biochemistry and Molecular Medicine, Université de Montréal, QC, Canada
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106
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Glineburg MR, Todd PK, Charlet-Berguerand N, Sellier C. Repeat-associated non-AUG (RAN) translation and other molecular mechanisms in Fragile X Tremor Ataxia Syndrome. Brain Res 2018; 1693:43-54. [PMID: 29453961 PMCID: PMC6010627 DOI: 10.1016/j.brainres.2018.02.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/31/2018] [Accepted: 02/02/2018] [Indexed: 11/11/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset inherited neurodegenerative disorder characterized by progressive intention tremor, gait ataxia and dementia associated with mild brain atrophy. The cause of FXTAS is a premutation expansion, of 55 to 200 CGG repeats localized within the 5'UTR of FMR1. These repeats are transcribed in the sense and antisense directions into mutants RNAs, which have increased expression in FXTAS. Furthermore, CGG sense and CCG antisense expanded repeats are translated into novel proteins despite their localization in putatively non-coding regions of the transcript. Here we focus on two proposed disease mechanisms for FXTAS: 1) RNA gain-of-function, whereby the mutant RNAs bind specific proteins and preclude their normal functions, and 2) repeat-associated non-AUG (RAN) translation, whereby translation through the CGG or CCG repeats leads to the production of toxic homopolypeptides, which in turn interfere with a variety of cellular functions. Here, we analyze the data generated to date on both of these potential molecular mechanisms and lay out a path forward for determining which factors drive FXTAS pathogenicity.
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Affiliation(s)
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Veteran's Affairs Medical Center, Ann Arbor, MI 48105, USA
| | - Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Chantal Sellier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France.
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107
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Ravanidis S, Kattan FG, Doxakis E. Unraveling the Pathways to Neuronal Homeostasis and Disease: Mechanistic Insights into the Role of RNA-Binding Proteins and Associated Factors. Int J Mol Sci 2018; 19:ijms19082280. [PMID: 30081499 PMCID: PMC6121432 DOI: 10.3390/ijms19082280] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 07/26/2018] [Accepted: 07/31/2018] [Indexed: 12/13/2022] Open
Abstract
The timing, dosage and location of gene expression are fundamental determinants of brain architectural complexity. In neurons, this is, primarily, achieved by specific sets of trans-acting RNA-binding proteins (RBPs) and their associated factors that bind to specific cis elements throughout the RNA sequence to regulate splicing, polyadenylation, stability, transport and localized translation at both axons and dendrites. Not surprisingly, misregulation of RBP expression or disruption of its function due to mutations or sequestration into nuclear or cytoplasmic inclusions have been linked to the pathogenesis of several neuropsychiatric and neurodegenerative disorders such as fragile-X syndrome, autism spectrum disorders, spinal muscular atrophy, amyotrophic lateral sclerosis and frontotemporal dementia. This review discusses the roles of Pumilio, Staufen, IGF2BP, FMRP, Sam68, CPEB, NOVA, ELAVL, SMN, TDP43, FUS, TAF15, and TIA1/TIAR in RNA metabolism by analyzing their specific molecular and cellular function, the neurological symptoms associated with their perturbation, and their axodendritic transport/localization along with their target mRNAs as part of larger macromolecular complexes termed ribonucleoprotein (RNP) granules.
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Affiliation(s)
- Stylianos Ravanidis
- Basic Sciences Division I, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece.
| | - Fedon-Giasin Kattan
- Basic Sciences Division I, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece.
| | - Epaminondas Doxakis
- Basic Sciences Division I, Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece.
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108
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Abstract
Aging-related neurodegenerative diseases are progressive and fatal neurological diseases that are characterized by irreversible neuron loss and gliosis. With a growing population of aging individuals, there is a pressing need to better understand the basic biology underlying these diseases. Although diverse disease mechanisms have been implicated in neurodegeneration, a common theme of altered RNA processing has emerged as a unifying contributing factor to neurodegenerative disease. RNA processing includes a series of distinct processes, including RNA splicing, transport and stability, as well as the biogenesis of non-coding RNAs. Here, we highlight how some of these mechanisms are altered in neurodegenerative disease, including the mislocalization of RNA-binding proteins and their sequestration induced by microsatellite repeats, microRNA biogenesis alterations and defective tRNA biogenesis, as well as changes to long-intergenic non-coding RNAs. We also highlight potential therapeutic interventions for each of these mechanisms. Summary: In this At a Glance review, Edward Lee and co-authors provide an overview of RNA metabolism defects, including mislocalization of RNA-binding proteins and microRNA biogenesis alterations, that contribute to neurodegenerative disease pathology.
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Affiliation(s)
- Elaine Y Liu
- Translational Neuropathology Research Laboratories, Perelman School of Med. Univ. of Pennsylvania, 613A Stellar Chance Laboratories, Philadelphia, PA 19104, USA
| | - Christopher P Cali
- Translational Neuropathology Research Laboratories, Perelman School of Med. Univ. of Pennsylvania, 613A Stellar Chance Laboratories, Philadelphia, PA 19104, USA
| | - Edward B Lee
- Translational Neuropathology Research Laboratories, Perelman School of Med. Univ. of Pennsylvania, 613A Stellar Chance Laboratories, Philadelphia, PA 19104, USA
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109
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Derbis M, Konieczny P, Walczak A, Sekrecki M, Sobczak K. Quantitative Evaluation of Toxic Polyglycine Biosynthesis and Aggregation in Cell Models Expressing Expanded CGG Repeats. Front Genet 2018; 9:216. [PMID: 29971092 PMCID: PMC6018535 DOI: 10.3389/fgene.2018.00216] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 05/28/2018] [Indexed: 12/23/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder caused by expanded CGG (CGGexp) trinucleotides in the 5′UTR of the FMR1 gene encoding fragile X mental retardation protein (FMRP). The patients, with the number of the repeats ranging from 55 to 200, show specific manifestation of clinical symptoms that include intention tremor, gait ataxia, cognitive deficits, and brain atrophy. Accumulation of toxic polyglycine (FMRpolyG), a by-product of the CGGexp repeat-associated non-ATG (RAN) translation, is considered to be one of the main factors triggering neurodegenerative processes in FXTAS patients. Nevertheless, the nature of the FMRpolyG-induced cell damage, especially in the context of its soluble and inclusion-associated forms, is still elusive. Targeting either biosynthesis, cellular stability or aggregation capacity of toxic FMRpolyG could be considered as a potential therapeutic strategy for FXTAS. Therefore, we tested a variety of quantitative methods based on forced expression of genetic constructs carrying CGGexp repeats in the context of the FMR1 5′UTR fused to GFP, mCherry or Firefly luciferase gene in or out of frame to the polyglycine encoding sequence. We show that FMRpolyG translation either from native or an AUG-induced start codon as well as the translation yield of the FMRP open reading frame equivalent located downstream of the CGGexp element can be effectively estimated using fluorescence microscopy, flow cytometry or luciferase assay. We also quantitatively estimated soluble fraction and insoluble form of FMRpolyG aggregated in foci using an electrophoretic separation of cell lysates and fluorescence microscopy, respectively. Importantly, we show that dependent on a fusion tag, FMRpolyG has a different potential for aggregate formation. Our established protocols enable sensitive tracking of FMRP and FMRpolyG quantitative and qualitative changes after treatment with potential therapeutic agents for FXTAS. Furthermore, they can be modified for application to other RAN translation- and aggregation-related diseases.
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Affiliation(s)
- Magdalena Derbis
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Patryk Konieczny
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Agnieszka Walczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Michal Sekrecki
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
| | - Krzysztof Sobczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, Poland
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110
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Muslimov IA, Eom T, Iacoangeli A, Chuang SC, Hukema RK, Willemsen R, Stefanov DG, Wong RKS, Tiedge H. BC RNA Mislocalization in the Fragile X Premutation. eNeuro 2018; 5:ENEURO.0091-18.2018. [PMID: 29766042 PMCID: PMC5952321 DOI: 10.1523/eneuro.0091-18.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 03/20/2018] [Accepted: 03/27/2018] [Indexed: 12/27/2022] Open
Abstract
Fragile X premutation disorder is caused by CGG triplet repeat expansions in the 5' untranslated region of FMR1 mRNA. The question of how expanded CGG repeats cause disease is a subject of continuing debate. Our work indicates that CGG-repeat structures compete with regulatory BC1 RNA for access to RNA transport factor hnRNP A2. As a result, BC1 RNA is mislocalized in vivo, as its synapto-dendritic presence is severely diminished in brains of CGG-repeat knock-in animals (a premutation mouse model). Lack of BC1 RNA is known to cause seizure activity and cognitive dysfunction. Our working hypothesis thus predicted that absence, or significantly reduced presence, of BC1 RNA in synapto-dendritic domains of premutation animal neurons would engender cognate phenotypic alterations. Testing this prediction, we established epileptogenic susceptibility and cognitive impairments as major phenotypic abnormalities of CGG premutation mice. In CA3 hippocampal neurons of such animals, synaptic release of glutamate elicits neuronal hyperexcitability in the form of group I metabotropic glutamate receptor-dependent prolonged epileptiform discharges. CGG-repeat knock-in animals are susceptible to sound-induced seizures and are cognitively impaired as revealed in the Attentional Set Shift Task. These phenotypic disturbances occur in young-adult premutation animals, indicating that a neurodevelopmental deficit is an early-initial manifestation of the disorder. The data are consistent with the notion that RNA mislocalization can contribute to pathogenesis.
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Affiliation(s)
- Ilham A. Muslimov
- The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, New York 11203
- Department of Physiology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, New York 11203
| | - Taesun Eom
- The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, New York 11203
- Department of Physiology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, New York 11203
| | - Anna Iacoangeli
- The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, New York 11203
- Department of Physiology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, New York 11203
| | - Shih-Chieh Chuang
- The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, New York 11203
- Department of Physiology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, New York 11203
| | - Renate K. Hukema
- Department of Clinical Genetics, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands
| | - Dimitre G. Stefanov
- Statistical Design and Analysis, Research Division, State University of New York Downstate Medical Center, Brooklyn, New York 11203
| | - Robert K. S. Wong
- The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, New York 11203
- Department of Physiology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, New York 11203
- Department of Neurology, State University of New York Downstate Medical Center, Brooklyn, New York 11203
| | - Henri Tiedge
- The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, New York 11203
- Department of Physiology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, New York 11203
- Department of Neurology, State University of New York Downstate Medical Center, Brooklyn, New York 11203
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111
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Angelbello AJ, Chen JL, Childs-Disney JL, Zhang P, Wang ZF, Disney MD. Using Genome Sequence to Enable the Design of Medicines and Chemical Probes. Chem Rev 2018; 118:1599-1663. [PMID: 29322778 DOI: 10.1021/acs.chemrev.7b00504] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Rapid progress in genome sequencing technology has put us firmly into a postgenomic era. A key challenge in biomedical research is harnessing genome sequence to fulfill the promise of personalized medicine. This Review describes how genome sequencing has enabled the identification of disease-causing biomolecules and how these data have been converted into chemical probes of function, preclinical lead modalities, and ultimately U.S. Food and Drug Administration (FDA)-approved drugs. In particular, we focus on the use of oligonucleotide-based modalities to target disease-causing RNAs; small molecules that target DNA, RNA, or protein; the rational repurposing of known therapeutic modalities; and the advantages of pharmacogenetics. Lastly, we discuss the remaining challenges and opportunities in the direct utilization of genome sequence to enable design of medicines.
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Affiliation(s)
- Alicia J Angelbello
- Departments of Chemistry and Neuroscience, The Scripps Research Institute , 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Jonathan L Chen
- Departments of Chemistry and Neuroscience, The Scripps Research Institute , 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Jessica L Childs-Disney
- Departments of Chemistry and Neuroscience, The Scripps Research Institute , 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Peiyuan Zhang
- Departments of Chemistry and Neuroscience, The Scripps Research Institute , 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Zi-Fu Wang
- Departments of Chemistry and Neuroscience, The Scripps Research Institute , 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Matthew D Disney
- Departments of Chemistry and Neuroscience, The Scripps Research Institute , 130 Scripps Way, Jupiter, Florida 33458, United States
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112
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Deregulation of RNA Metabolism in Microsatellite Expansion Diseases. ADVANCES IN NEUROBIOLOGY 2018; 20:213-238. [PMID: 29916021 DOI: 10.1007/978-3-319-89689-2_8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
RNA metabolism impacts different steps of mRNA life cycle including splicing, polyadenylation, nucleo-cytoplasmic export, translation, and decay. Growing evidence indicates that defects in any of these steps lead to devastating diseases in humans. This chapter reviews the various RNA metabolic mechanisms that are disrupted in Myotonic Dystrophy-a trinucleotide repeat expansion disease-due to dysregulation of RNA-Binding Proteins. We also compare Myotonic Dystrophy to other microsatellite expansion disorders and describe how some of these mechanisms commonly exert direct versus indirect effects toward disease pathologies.
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113
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Boivin M, Willemsen R, Hukema RK, Sellier C. Potential pathogenic mechanisms underlying Fragile X Tremor Ataxia Syndrome: RAN translation and/or RNA gain-of-function? Eur J Med Genet 2017; 61:674-679. [PMID: 29223504 DOI: 10.1016/j.ejmg.2017.11.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 09/19/2017] [Accepted: 11/08/2017] [Indexed: 10/18/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is an inherited neurodegenerative disease caused by an expansion of 55-200 CGG repeats located in the FMR1 gene. The main clinical and neuropathological features of FXTAS are progressive intention tremor and gait ataxia associated with brain atrophy, neuronal cell loss and presence of ubiquitin-positive intranuclear inclusions in both neurons and astrocytes. At the molecular level, FXTAS is characterized by increased expression of FMR1 sense and antisense RNA containing expanded CGG or GGC repeats, respectively. Here, we discuss the putative molecular mechanisms underlying FXTAS and notably recent reports that expanded CGG and GGC repeats may be pathogenic through RAN translation into toxic proteins.
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Affiliation(s)
- Manon Boivin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, 3015 CN Rotterdam, The Netherlands
| | - Renate K Hukema
- Department of Clinical Genetics, Erasmus MC, 3015 CN Rotterdam, The Netherlands
| | - Chantal Sellier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France.
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114
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Newman JRB, Conesa A, Mika M, New FN, Onengut-Gumuscu S, Atkinson MA, Rich SS, McIntyre LM, Concannon P. Disease-specific biases in alternative splicing and tissue-specific dysregulation revealed by multitissue profiling of lymphocyte gene expression in type 1 diabetes. Genome Res 2017; 27:1807-1815. [PMID: 29025893 PMCID: PMC5668939 DOI: 10.1101/gr.217984.116] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 09/13/2017] [Indexed: 12/22/2022]
Abstract
Genome-wide association studies (GWAS) have identified multiple, shared allelic associations with many autoimmune diseases. However, the pathogenic contributions of variants residing in risk loci remain unresolved. The location of the majority of shared disease-associated variants in noncoding regions suggests they contribute to risk of autoimmunity through effects on gene expression in the immune system. In the current study, we test this hypothesis by applying RNA sequencing to CD4+, CD8+, and CD19+ lymphocyte populations isolated from 81 subjects with type 1 diabetes (T1D). We characterize and compare the expression patterns across these cell types for three gene sets: all genes, the set of genes implicated in autoimmune disease risk by GWAS, and the subset of these genes specifically implicated in T1D. We performed RNA sequencing and aligned the reads to both the human reference genome and a catalog of all possible splicing events developed from the genome, thereby providing a comprehensive evaluation of the roles of gene expression and alternative splicing (AS) in autoimmunity. Autoimmune candidate genes displayed greater expression specificity in the three lymphocyte populations relative to other genes, with significantly increased levels of splicing events, particularly those predicted to have substantial effects on protein isoform structure and function (e.g., intron retention, exon skipping). The majority of single-nucleotide polymorphisms within T1D-associated loci were also associated with one or more cis-expression quantitative trait loci (cis-eQTLs) and/or splicing eQTLs. Our findings highlight a substantial, and previously underrecognized, role for AS in the pathogenesis of autoimmune disorders and particularly for T1D.
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Affiliation(s)
- Jeremy R B Newman
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32610, USA
| | - Ana Conesa
- Department of Microbiology and Cell Science, Institute for Food and Agricultural Sciences, University of Florida, Gainesville, Florida 32610, USA
- Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
| | - Matthew Mika
- Center for Public Health Genomics and Department of Public Health Sciences, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Felicia N New
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32610, USA
| | - Suna Onengut-Gumuscu
- Center for Public Health Genomics and Department of Public Health Sciences, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Mark A Atkinson
- Diabetes Institute, University of Florida, Gainesville, Florida 32610, USA
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, Florida 32610, USA
| | - Stephen S Rich
- Center for Public Health Genomics and Department of Public Health Sciences, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Lauren M McIntyre
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32610, USA
- Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
| | - Patrick Concannon
- Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, Florida 32610, USA
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115
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Galganski L, Urbanek MO, Krzyzosiak WJ. Nuclear speckles: molecular organization, biological function and role in disease. Nucleic Acids Res 2017; 45:10350-10368. [PMID: 28977640 PMCID: PMC5737799 DOI: 10.1093/nar/gkx759] [Citation(s) in RCA: 298] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/18/2017] [Indexed: 12/13/2022] Open
Abstract
The nucleoplasm is not homogenous; it consists of many types of nuclear bodies, also known as nuclear domains or nuclear subcompartments. These self-organizing structures gather machinery involved in various nuclear activities. Nuclear speckles (NSs) or splicing speckles, also called interchromatin granule clusters, were discovered as sites for splicing factor storage and modification. Further studies on transcription and mRNA maturation and export revealed a more general role for splicing speckles in RNA metabolism. Here, we discuss the functional implications of the localization of numerous proteins crucial for epigenetic regulation, chromatin organization, DNA repair and RNA modification to nuclear speckles. We highlight recent advances suggesting that NSs facilitate integrated regulation of gene expression. In addition, we consider the influence of abundant regulatory and signaling proteins, i.e. protein kinases and proteins involved in protein ubiquitination, phosphoinositide signaling and nucleoskeletal organization, on pre-mRNA synthesis and maturation. While many of these regulatory proteins act within NSs, direct evidence for mRNA metabolism events occurring in NSs is still lacking. NSs contribute to numerous human diseases, including cancers and viral infections. In addition, recent data have demonstrated close relationships between these structures and the development of neurological disorders.
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Affiliation(s)
- Lukasz Galganski
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Martyna O Urbanek
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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116
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Abstract
Neurodegeneration is a leading cause of death in the developed world and a natural, albeit unfortunate, consequence of longer-lived populations. Despite great demand for therapeutic intervention, it is often the case that these diseases are insufficiently understood at the basic molecular level. What little is known has prompted much hopeful speculation about a generalized mechanistic thread that ties these disparate conditions together at the subcellular level and can be exploited for broad curative benefit. In this review, we discuss a prominent theory supported by genetic and pathological changes in an array of neurodegenerative diseases: that neurons are particularly vulnerable to disruption of RNA-binding protein dosage and dynamics. Here we synthesize the progress made at the clinical, genetic, and biophysical levels and conclude that this perspective offers the most parsimonious explanation for these mysterious diseases. Where appropriate, we highlight the reciprocal benefits of cross-disciplinary collaboration between disease specialists and RNA biologists as we envision a future in which neurodegeneration declines and our understanding of the broad importance of RNA processing deepens.
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Affiliation(s)
- Erin G Conlon
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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117
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Abstract
Sellier et al. (2017) show that translation of expanded CGG repeats in fragile X-associated tremor/ataxia syndrome is initiated at an upstream ACG near-cognate start codon. The resulting polyglycine-containing protein, but not repeat RNA, is pathogenic by disrupting the nuclear lamina.
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Affiliation(s)
- Fen-Biao Gao
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
| | - Joel D Richter
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
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118
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Castro H, Kul E, Buijsen RAM, Severijnen LAWFM, Willemsen R, Hukema RK, Stork O, Santos M. Selective rescue of heightened anxiety but not gait ataxia in a premutation 90CGG mouse model of Fragile X-associated tremor/ataxia syndrome. Hum Mol Genet 2017; 26:2133-2145. [PMID: 28369393 DOI: 10.1093/hmg/ddx108] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/08/2017] [Indexed: 02/02/2023] Open
Abstract
A CGG-repeat expansion in the premutation range in the Fragile X mental retardation 1 gene (FMR1) has been identified as the genetic cause of Fragile X-associated tremor/ataxia syndrome (FXTAS), a late-onset neurodegenerative disorder that manifests with action tremor, gait ataxia and cognitive impairments. In this study, we used a bigenic mouse model, in which expression of a 90CGG premutation tract is activated in neural cells upon doxycycline administration-P90CGG mouse model. We, here, demonstrate the behavioural manifestation of clinically relevant features of FXTAS patients and premutation carrier individuals in this inducible mouse model. P90CGG mice display heightened anxiety, deficits in motor coordination and impaired gait and represent the first FXTAS model that exhibits an ataxia phenotype as observed in patients. The behavioural phenotype is accompanied by the formation of ubiquitin/FMRpolyglycine-positive intranuclear inclusions, as another hallmark of FXTAS, in the cerebellum, hippocampus and amygdala. Strikingly, upon cessation of transgene induction the anxiety phenotype of mice recovers along with a reduction of intranuclear inclusions in dentate gyrus and amygdala. In contrast, motor function deteriorates further and no reduction in intranuclear inclusions can be observed in the cerebellum. Our data thus demonstrate that expression of a 90CGG premutation expansion outside of the FMR1 context is sufficient to evoke an FXTAS-like behavioural phenotype. Brain region-specific neuropathology and (partial) behavioural reversibility make the inducible P90CGG a valuable mouse model for testing pathogenic mechanisms and therapeutic intervention methods.
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Affiliation(s)
- Hoanna Castro
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Emre Kul
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Ronald A M Buijsen
- Department of Clinical Genetics, Erasmus MC, 3000 CA Rotterdam, The Netherlands
| | | | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, 3000 CA Rotterdam, The Netherlands
| | - Renate K Hukema
- Department of Clinical Genetics, Erasmus MC, 3000 CA Rotterdam, The Netherlands
| | - Oliver Stork
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University, 39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg
| | - Mónica Santos
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University, 39120 Magdeburg, Germany
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119
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Man L, Lekovich J, Rosenwaks Z, Gerhardt J. Fragile X-Associated Diminished Ovarian Reserve and Primary Ovarian Insufficiency from Molecular Mechanisms to Clinical Manifestations. Front Mol Neurosci 2017; 10:290. [PMID: 28955201 PMCID: PMC5600956 DOI: 10.3389/fnmol.2017.00290] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 08/28/2017] [Indexed: 12/12/2022] Open
Abstract
Fragile X syndrome (FXS), is caused by a loss-of-function mutation in the FMR1 gene located on the X-chromosome, which leads to the most common cause of inherited intellectual disability in males and the leading single-gene defect associated with autism. A full mutation (FM) is represented by more than 200 CGG repeats within the FMR1 gene, resulting in FXS. A FM is inherited from women carrying a FM or a premutation (PM; 55–200 CGG repeats) allele. PM is associated with phenotypes distinct from those associated with FM. Some manifestations of the PM are unique; fragile-X-associated tremor/ataxia syndrome (FXTAS), and fragile-X-associated primary ovarian insufficiency (FXPOI), while others tend to be non-specific such as intellectual disability. In addition, women carrying a PM may suffer from subfertility or infertility. There is a need to elucidate whether the impairment of ovarian function found in PM carriers arises during the primordial germ cell (PGC) development stage, or due to a rapidly diminishing oocyte pool throughout life or even both. Due to the possibility of expansion into a FM in the next generation, and other ramifications, carrying a PM can have an enormous impact on one’s life; therefore, preconception counseling for couples carrying the PM is of paramount importance. In this review, we will elaborate on the clinical manifestations in female PM carriers and propose the definition of fragile-X-associated diminished ovarian reserve (FXDOR), then we will review recent scientific findings regarding possible mechanisms leading to FXDOR and FXPOI. Lastly, we will discuss counseling, preventative measures and interventions available for women carrying a PM regarding different aspects of their reproductive life, fertility treatment, pregnancy, prenatal testing, contraception and fertility preservation options.
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Affiliation(s)
- Limor Man
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| | - Jovana Lekovich
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| | - Zev Rosenwaks
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
| | - Jeannine Gerhardt
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell MedicineNew York, NY, United States
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120
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Tseng E, Tang HT, AlOlaby RR, Hickey L, Tassone F. Altered expression of the FMR1 splicing variants landscape in premutation carriers. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:1117-1126. [PMID: 28888471 DOI: 10.1016/j.bbagrm.2017.08.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 08/26/2017] [Accepted: 08/26/2017] [Indexed: 01/17/2023]
Abstract
FMR1 premutation carriers (55-200 CGG repeats) are at risk for developing Fragile X-associated Tremor/Ataxia Syndrome (FXTAS), an adult onset neurodegenerative disorder. Approximately 20% of female carriers will develop Fragile X-associated Primary Ovarian Insufficiency (FXPOI), in addition to a number of clinical problems affecting premutation carriers throughout their life span. Marked elevation in FMR1 mRNA levels have been observed with premutation alleles resulting in RNA toxicity, the leading molecular mechanism proposed for the FMR1 associated disorders observed in premutation carriers. The FMR1 gene undergoes alternative splicing and we have recently reported that the relative abundance of all FMR1 mRNA isoforms is significantly increased in premutation carriers. In this study, we characterized the transcriptional FMR1 isoforms distribution pattern in different tissues and identified a total of 49 isoforms, some of which observed only in premutation carriers and which might play a role in the pathogenesis of FXTAS. Further, we investigated the distribution pattern and expression levels of the FMR1 isoforms in asymptomatic premutation carriers and in those with FXTAS and found no significant differences between the two groups. Our findings suggest that the characterization of the expression levels of the different FMR1 isoforms is fundamental for understanding the regulation of the FMR1 gene as imbalance in their expression could lead to an altered functional diversity with neurotoxic consequences. Their characterization will also help to elucidating the mechanism(s) by which "toxic gain of function" of the FMR1 mRNA may play a role in FXTAS and/or in the other FMR1-associated conditions.
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Affiliation(s)
| | - Hiu-Tung Tang
- Biochemistry and Molecular Medicine, UC Davis, Sacramento, CA 95817, USA
| | - Reem Rafik AlOlaby
- Biochemistry and Molecular Medicine, UC Davis, Sacramento, CA 95817, USA
| | - Luke Hickey
- Pacific Biosciences, Inc., Menlo Park, CA 94025, USA
| | - Flora Tassone
- Biochemistry and Molecular Medicine, UC Davis, Sacramento, CA 95817, USA; MIND Institute, UC Davis, Sacramento, CA 95817, USA.
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121
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Hayward BE, Kumari D, Usdin K. Recent advances in assays for the fragile X-related disorders. Hum Genet 2017; 136:1313-1327. [PMID: 28866801 DOI: 10.1007/s00439-017-1840-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 08/24/2017] [Indexed: 12/17/2022]
Abstract
The fragile X-related disorders are a group of three clinical conditions resulting from the instability of a CGG-repeat tract at the 5' end of the FMR1 transcript. Fragile X-associated tremor/ataxia syndrome (FXTAS) and fragile X-associated primary ovarian insufficiency (FXPOI) are disorders seen in carriers of FMR1 alleles with 55-200 repeats. Female carriers of these premutation (PM) alleles are also at risk of having a child who has an FMR1 allele with >200 repeats. Most of these full mutation (FM) alleles are epigenetically silenced resulting in a deficit of the FMR1 gene product, FMRP. This results in fragile X Syndrome (FXS), the most common heritable cause of intellectual disability and autism. The diagnosis and study of these disorders is challenging, in part because the detection of alleles with large repeat numbers has, until recently, been either time-consuming or unreliable. This problem is compounded by the mosaicism for repeat length and/or DNA methylation that is frequently seen in PM and FM carriers. Furthermore, since AGG interruptions in the repeat tract affect the risk that a FM allele will be maternally transmitted, the ability to accurately detect these interruptions in female PM carriers is an additional challenge that must be met. This review will discuss some of the pros and cons of some recently described assays for these disorders, including those that detect FMRP levels directly, as well as emerging technologies that promise to improve the diagnosis of these conditions and to be useful in both basic and translational research settings.
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Affiliation(s)
- Bruce E Hayward
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, Building 8, Room 2A19, National Institutes of Health, 8 Center Drive MSC 0830, Bethesda, MD, 20892, USA
| | - Daman Kumari
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, Building 8, Room 2A19, National Institutes of Health, 8 Center Drive MSC 0830, Bethesda, MD, 20892, USA
| | - Karen Usdin
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, Building 8, Room 2A19, National Institutes of Health, 8 Center Drive MSC 0830, Bethesda, MD, 20892, USA.
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122
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Rohilla KJ, Gagnon KT. RNA biology of disease-associated microsatellite repeat expansions. Acta Neuropathol Commun 2017; 5:63. [PMID: 28851463 PMCID: PMC5574247 DOI: 10.1186/s40478-017-0468-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/22/2017] [Indexed: 12/13/2022] Open
Abstract
Microsatellites, or simple tandem repeat sequences, occur naturally in the human genome and have important roles in genome evolution and function. However, the expansion of microsatellites is associated with over two dozen neurological diseases. A common denominator among the majority of these disorders is the expression of expanded tandem repeat-containing RNA, referred to as xtrRNA in this review, which can mediate molecular disease pathology in multiple ways. This review focuses on the potential impact that simple tandem repeat expansions can have on the biology and metabolism of RNA that contain them and underscores important gaps in understanding. Merging the molecular biology of repeat expansion disorders with the current understanding of RNA biology, including splicing, transcription, transport, turnover and translation, will help clarify mechanisms of disease and improve therapeutic development.
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123
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Robin G, López JR, Espinal GM, Hulsizer S, Hagerman PJ, Pessah IN. Calcium dysregulation and Cdk5-ATM pathway involved in a mouse model of fragile X-associated tremor/ataxia syndrome. Hum Mol Genet 2017; 26:2649-2666. [PMID: 28444183 PMCID: PMC5886271 DOI: 10.1093/hmg/ddx148] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/06/2017] [Accepted: 04/12/2017] [Indexed: 12/30/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurological disorder that affects premutation carriers with 55-200 CGG-expansion repeats (preCGG) in FMR1, presenting with early alterations in neuronal network formation and function that precede neurodegeneration. Whether intranuclear inclusions containing DNA damage response (DDR) proteins are causally linked to abnormal synaptic function, neuronal growth and survival are unknown. In a mouse that harbors a premutation CGG expansion (preCGG), cortical and hippocampal FMRP expression is moderately reduced from birth through adulthood, with greater FMRP reductions in the soma than in the neurite, despite several-fold elevation of Fmr1 mRNA levels. Resting cytoplasmic calcium concentration ([Ca2+]i) in cultured preCGG hippocampal neurons is chronically elevated, 3-fold compared to Wt; elevated ROS and abnormal glutamatergic responses are detected at 14 DIV. Elevated µ-calpain activity and a higher p25/p35 ratio in the cortex of preCGG young adult mice indicate abnormal Cdk5 regulation. In support, the Cdk5 substrate, ATM, is upregulated by 1.5- to 2-fold at P0 and 6 months in preCGG brain, as is p-Ser1981-ATM. Bax:Bcl-2 is 30% higher in preCGG brain, indicating a greater vulnerability to apoptotic activation. Elevated [Ca2+]i, ROS, and DDR signals are normalized with dantrolene. Chronic [Ca2+]i dysregulation amplifies Cdk5-ATM signaling, possibly linking impaired glutamatergic signaling and DDR to neurodegeneration in preCGG brain.
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Affiliation(s)
- Gaëlle Robin
- Department Molecular Biosciences, School of Veterinary Medicine, Davis, CA, USA
| | - José R. López
- Department Molecular Biosciences, School of Veterinary Medicine, Davis, CA, USA
| | - Glenda M. Espinal
- Department of Biochemistry and Molecular Medicine, UC Davis, Davis, CA 95616, USA
| | - Susan Hulsizer
- Department Molecular Biosciences, School of Veterinary Medicine, Davis, CA, USA
| | - Paul J. Hagerman
- Department of Biochemistry and Molecular Medicine, UC Davis, Davis, CA 95616, USA
- Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, Sacramento, CA 95817, USA
| | - Isaac N. Pessah
- Department Molecular Biosciences, School of Veterinary Medicine, Davis, CA, USA
- Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, Sacramento, CA 95817, USA
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124
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Urbanek MO, Krzyzosiak WJ. Discriminating RNA variants with single-molecule allele-specific FISH. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 773:230-241. [DOI: 10.1016/j.mrrev.2016.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 09/12/2016] [Accepted: 09/13/2016] [Indexed: 10/21/2022]
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125
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Wheeler A, Raspa M, Hagerman R, Mailick M, Riley C. Implications of the FMR1 Premutation for Children, Adolescents, Adults, and Their Families. Pediatrics 2017; 139:S172-S182. [PMID: 28814538 PMCID: PMC5621635 DOI: 10.1542/peds.2016-1159d] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/24/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Given the nature of FMR1 gene expansions, most biological mothers, and often multiple other family members of children with fragile X syndrome (FXS), will have a premutation, which may increase individual and family vulnerabilities. This article summarizes important gaps in knowledge and notes potential implications for pediatric providers with regard to developmental and medical risks for children and adolescents with an FMR1 premutation, including possible implications into adulthood. METHODS A structured electronic literature search was conducted on FMR1 pre- and full mutations, yielding a total of 306 articles examined. Of these, 116 focused primarily on the premutation and are included in this review. RESULTS Based on the literature review, 5 topic areas are discussed: genetics and epidemiology; phenotypic characteristics of individuals with the premutation; implications for carrier parents of children with FXS; implications for the extended family; and implications for pediatricians. CONCLUSIONS Although the premutation phenotype is typically less severe in clinical presentation than in FXS, premutation carriers are much more common and are therefore more likely to be seen in a typical pediatric practice. In addition, there is a wide range of medical, cognitive/developmental, and psychiatric associated features that individuals with a premutation are at increased risk for having, which underscores the importance of awareness on the part of pediatricians in identifying and monitoring premutation carriers and recognizing the impact this identification may have on family members.
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Affiliation(s)
- Anne Wheeler
- RTI International, Research Triangle Park, North Carolina;
| | - Melissa Raspa
- RTI International, Research Triangle Park, North Carolina
| | - Randi Hagerman
- MIND Institute, University of California at Davis, Sacramento, California
| | - Marsha Mailick
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin; and
| | - Catharine Riley
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia
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126
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Morriss GR, Cooper TA. Protein sequestration as a normal function of long noncoding RNAs and a pathogenic mechanism of RNAs containing nucleotide repeat expansions. Hum Genet 2017; 136:1247-1263. [PMID: 28484853 DOI: 10.1007/s00439-017-1807-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 04/28/2017] [Indexed: 12/12/2022]
Abstract
An emerging class of long noncoding RNAs (lncRNAs) function as decoy molecules that bind and sequester proteins thereby inhibiting their normal functions. Titration of proteins by lncRNAs has wide-ranging effects affecting nearly all steps in gene expression. While decoy lncRNAs play a role in normal physiology, RNAs expressed from alleles containing nucleotide repeat expansions can be pathogenic due to protein sequestration resulting in disruption of normal functions. This review focuses on commonalities between decoy lncRNAs that regulate gene expression by competitive inhibition of protein function through sequestration and specific examples of nucleotide repeat expansion disorders mediated by toxic RNA that sequesters RNA-binding proteins and impedes their normal functions. Understanding how noncoding RNAs compete with various RNA and DNA molecules for binding of regulatory proteins will provide insight into how similar mechanisms contribute to disease pathogenesis.
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Affiliation(s)
- Ginny R Morriss
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Thomas A Cooper
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.
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127
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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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128
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Urbanek MO, Michalak M, Krzyzosiak WJ. 2D and 3D FISH of expanded repeat RNAs in human lymphoblasts. Methods 2017; 120:49-57. [PMID: 28404480 DOI: 10.1016/j.ymeth.2017.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/09/2017] [Accepted: 04/05/2017] [Indexed: 12/18/2022] Open
Abstract
The first methods for visualizing RNAs within cells were designed for simple imaging of specific transcripts in cells or tissues and since then significant technical advances have been made in this field. Today, high-resolution images can be obtained, enabling visualization of single transcript molecules, quantitative analyses of images, and precise localization of RNAs within cells as well as co-localization of transcripts with specific proteins or other molecules. In addition, tracking of RNA dynamics within single cell has become possible. RNA imaging techniques have been utilized for investigating the role of mutant RNAs in a number of human disorders caused by simple microsatellite expansions. These diseases include myotonic dystrophy type 1 and 2, amyotrophic lateral sclerosis/frontotemporal dementia, fragile X-associated tremor/ataxia syndrome, and Huntington's disease. Mutant RNAs with expanded repeats tend to aggregate predominantly within cell nuclei, forming structures called RNA foci. In this study, we demonstrate methods for fluorescent visualization of RNAs in both fixed and living cells using the example of RNAs containing various expanded repeat tracts (CUG, CCUG, GGGGCC, CGG, and CAG) from experiment design to image analysis. We describe in detail 2D and 3D fluorescence in situ hybridization (FISH) protocols for imaging expanded repeats RNAs, and we review briefly live imaging techniques used to characterize RNA foci formed by mutant RNAs. These methods could be used to image the entire cellular pathway of RNAs, from transcription to degradation.
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Affiliation(s)
- Martyna O Urbanek
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland
| | - Michal Michalak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland.
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129
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Weber SC. Sequence-encoded material properties dictate the structure and function of nuclear bodies. Curr Opin Cell Biol 2017; 46:62-71. [PMID: 28343140 DOI: 10.1016/j.ceb.2017.03.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 02/13/2017] [Accepted: 03/07/2017] [Indexed: 12/21/2022]
Abstract
Concomitant with packaging the genome, the cell nucleus must also spatially organize the nucleoplasm. This complex mixture of proteins and nucleic acids partitions into a variety of phase-separated, membraneless organelles called nuclear bodies. Significant progress has been made in understanding the relationship between the material properties of nuclear bodies and their structural and functional consequences. Furthermore, the molecular basis of these condensed phases is beginning to emerge. Here, I review the latest work in this exciting field, highlighting recent advances and new challenges.
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Affiliation(s)
- Stephanie C Weber
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada.
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130
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Ariza J, Rogers H, Hartvigsen A, Snell M, Dill M, Judd D, Hagerman P, Martínez-Cerdeño V. Iron accumulation and dysregulation in the putamen in fragile X-associated tremor/ataxia syndrome. Mov Disord 2017; 32:585-591. [PMID: 28233916 DOI: 10.1002/mds.26902] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 11/07/2016] [Accepted: 12/07/2016] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Fragile X-associated tremor/ataxia syndrome is an adult-onset disorder associated with premutation alleles of the FMR1 gene. This disorder is characterized by progressive action tremor, gait ataxia, and cognitive decline. Fragile X-associated tremor/ataxia syndrome pathology includes dystrophic white matter and intranuclear inclusions in neurons and astrocytes. We previously demonstrated that the transport of iron into the brain is altered in fragile X-associated tremor/ataxia syndrome; therefore, we also expect an alteration of iron metabolism in brain areas related to motor control. Iron is essential for cell metabolism, but uncomplexed iron leads to oxidative stress and contributes to the development of neurodegenerative diseases. We investigated a potential iron modification in the putamen - a structure that participates in motor learning and performance - in fragile X-associated tremor/ataxia syndrome. METHODS We used samples of putamen obtained from 9 fragile X-associated tremor/ataxia syndrome and 9 control cases to study iron localization using Perl's method, and iron-binding proteins using immunostaining. RESULTS We found increased iron deposition in neuronal and glial cells in the putamen in fragile X-associated tremor/ataxia syndrome. We also found a generalized decrease in the amount of the iron-binding proteins transferrin and ceruloplasmin, and decreased number of neurons and glial cells that contained ceruloplasmin. However, we found increased levels of iron, transferrin, and ceruloplasmin in microglial cells, indicating an attempt by the immune system to remove the excess iron. CONCLUSIONS Overall, found a deficit in proteins that eliminate extra iron from the cells with a concomitant increase in the deposit of cellular iron in the putamen in Fragile X-associated tremor/ataxia syndrome. © 2017 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Jeanelle Ariza
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, and the Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, Sacramento, California
| | - Hailee Rogers
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, and the Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, Sacramento, California
| | - Anna Hartvigsen
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, and the Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, Sacramento, California
| | - Melissa Snell
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, and the Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, Sacramento, California
| | - Michael Dill
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, and the Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, Sacramento, California
| | - Derek Judd
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, and the Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, Sacramento, California
| | - Paul Hagerman
- MIND Institute, UC Davis Medical Center, Sacramento, California.,Department of Biochemistry and Molecular Medicine, UC Davis School of Medicine, Sacramento, California
| | - Verónica Martínez-Cerdeño
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, and the Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, Sacramento, California.,MIND Institute, UC Davis Medical Center, Sacramento, California
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131
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Zhang N, Ashizawa T. RNA toxicity and foci formation in microsatellite expansion diseases. Curr Opin Genet Dev 2017; 44:17-29. [PMID: 28208060 DOI: 10.1016/j.gde.2017.01.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 01/04/2017] [Accepted: 01/18/2017] [Indexed: 12/11/2022]
Abstract
More than 30 incurable neurological and neuromuscular diseases are caused by simple microsatellite expansions consisted of 3-6 nucleotides. These repeats can occur in non-coding regions and often result in a dominantly inherited disease phenotype that is characteristic of a toxic RNA gain-of-function. The expanded RNA adopts unusual secondary structures, sequesters various RNA binding proteins to form insoluble nuclear foci, and causes cellular defects at a multisystem level. Nuclear foci are dynamic in size, shape and colocalization of RNA binding proteins in different expansion diseases and tissue types. This review sets to provide new insights into the disease mechanisms of RNA toxicity and foci modulation, in light of recent advancement on bi-directional transcription, antisense RNA, repeat-associated non-ATG translation and beyond.
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Affiliation(s)
- Nan Zhang
- Neurosciences Research Program, Houston Methodist Research Institute, Houston, TX 77030, United States; Division of Cell and Molecular Biology, South Kensington Campus, Imperial College London, London SW7 2AZ, UK
| | - Tetsuo Ashizawa
- Neurosciences Research Program, Houston Methodist Research Institute, Houston, TX 77030, United States.
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132
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Sellier C, Buijsen RAM, He F, Natla S, Jung L, Tropel P, Gaucherot A, Jacobs H, Meziane H, Vincent A, Champy MF, Sorg T, Pavlovic G, Wattenhofer-Donze M, Birling MC, Oulad-Abdelghani M, Eberling P, Ruffenach F, Joint M, Anheim M, Martinez-Cerdeno V, Tassone F, Willemsen R, Hukema RK, Viville S, Martinat C, Todd PK, Charlet-Berguerand N. Translation of Expanded CGG Repeats into FMRpolyG Is Pathogenic and May Contribute to Fragile X Tremor Ataxia Syndrome. Neuron 2017; 93:331-347. [PMID: 28065649 PMCID: PMC5263258 DOI: 10.1016/j.neuron.2016.12.016] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 10/06/2016] [Accepted: 12/02/2016] [Indexed: 11/26/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder caused by a limited expansion of CGG repeats in the 5′ UTR of FMR1. Two mechanisms are proposed to cause FXTAS: RNA gain-of-function, where CGG RNA sequesters specific proteins, and translation of CGG repeats into a polyglycine-containing protein, FMRpolyG. Here we developed transgenic mice expressing CGG repeat RNA with or without FMRpolyG. Expression of FMRpolyG is pathogenic, while the sole expression of CGG RNA is not. FMRpolyG interacts with the nuclear lamina protein LAP2β and disorganizes the nuclear lamina architecture in neurons differentiated from FXTAS iPS cells. Finally, expression of LAP2β rescues neuronal death induced by FMRpolyG. Overall, these results suggest that translation of expanded CGG repeats into FMRpolyG alters nuclear lamina architecture and drives pathogenesis in FXTAS. CGG repeats in the 5′ UTR of FMR1 are translated through initiation to an ACG codon Translation of CGG repeats in the polyglycine protein, FMRpolyG, is toxic in mice FMRpolyG binds and disrupts protein of the nuclear lamina
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Affiliation(s)
- Chantal Sellier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France.
| | - Ronald A M Buijsen
- Department of Clinical Genetics, Erasmus MC, 3015 Rotterdam, the Netherlands
| | - Fang He
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Veteran Association Health System, Ann Arbor, MI 48105, USA; Department of Biological and Health Sciences, Texas A&M University - Kingsville, Kingsville, TX 78363, USA
| | - Sam Natla
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Laura Jung
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Philippe Tropel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Angeline Gaucherot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Hugues Jacobs
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France; PHENOMIN, Institut Clinique de la Souris (ICS), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Hamid Meziane
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France; PHENOMIN, Institut Clinique de la Souris (ICS), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Alexandre Vincent
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Marie-France Champy
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France; PHENOMIN, Institut Clinique de la Souris (ICS), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Tania Sorg
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France; PHENOMIN, Institut Clinique de la Souris (ICS), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Guillaume Pavlovic
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France; PHENOMIN, Institut Clinique de la Souris (ICS), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Marie Wattenhofer-Donze
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France; PHENOMIN, Institut Clinique de la Souris (ICS), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Marie-Christine Birling
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France; PHENOMIN, Institut Clinique de la Souris (ICS), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Mustapha Oulad-Abdelghani
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Pascal Eberling
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Frank Ruffenach
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Mathilde Joint
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Mathieu Anheim
- Department of Neurology, University Hospital of Strasbourg, Hôpital de Hautepierre, 67200 Strasbourg, France
| | - Veronica Martinez-Cerdeno
- Department of Pathology and Laboratory Medicine, University of California, Davis, Sacramento, CA 95817, USA; Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, Sacramento, CA 95817, USA; M.I.N.D. Institute, University of California, Davis, Health System, Sacramento, CA 95817, USA
| | - Flora Tassone
- M.I.N.D. Institute, University of California, Davis, Health System, Sacramento, CA 95817, USA
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, 3015 Rotterdam, the Netherlands
| | - Renate K Hukema
- Department of Clinical Genetics, Erasmus MC, 3015 Rotterdam, the Netherlands
| | - Stéphane Viville
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France; Laboratoire de Diagnostic Génétique, UF3472 - Infertilité, Nouvel Hôpital Civil, 1 place de l'Hôpital, 67091 Strasbourg, France; IPPTS, 3 rue Koeberlé, 67000 Strasbourg, France
| | | | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Veteran Association Health System, Ann Arbor, MI 48105, USA
| | - Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, 67400 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67400 Illkirch, France.
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133
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Miranda DR, Wong M, Romer SH, McKee C, Garza-Vasquez G, Medina AC, Bahn V, Steele AD, Talmadge RJ, Voss AA. Progressive Cl- channel defects reveal disrupted skeletal muscle maturation in R6/2 Huntington's mice. J Gen Physiol 2016; 149:55-74. [PMID: 27899419 PMCID: PMC5217084 DOI: 10.1085/jgp.201611603] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 10/03/2016] [Accepted: 11/16/2016] [Indexed: 12/14/2022] Open
Abstract
The R6/2 mouse model of Huntington’s disease exhibits reduced skeletal muscle ClC-1 currents. Miranda et al. investigate early stages of disease in these mice and find an early and progressive disruption of ClC-1 as well as altered muscle maturation based on myosin heavy chain isoform expression. Huntington’s disease (HD) patients suffer from progressive and debilitating motor dysfunction. Previously, we discovered reduced skeletal muscle chloride channel (ClC-1) currents, inwardly rectifying potassium (Kir) channel currents, and membrane capacitance in R6/2 transgenic HD mice. The ClC-1 loss-of-function correlated with increased aberrant mRNA processing and decreased levels of full-length ClC-1 mRNA (Clcn1 gene). Physiologically, the resulting muscle hyperexcitability may help explain involuntary contractions of HD. In this study, the onset and progression of these defects are investigated in R6/2 mice, ranging from 3 wk old (presymptomatic) to 9–13 wk old (late-stage disease), and compared with age-matched wild-type (WT) siblings. The R6/2 ClC-1 current density and level of aberrantly spliced Clcn1 mRNA remain constant with age. In contrast, the ClC-1 current density increases, and the level of aberrantly spliced Clcn1 mRNA decreases with age in WT mice. The R6/2 ClC-1 properties diverge from WT before the onset of motor symptoms, which occurs at 5 wk of age. The relative decrease in R6/2 muscle capacitance also begins in 5-wk-old mice and is independent of fiber atrophy. Kir current density is consistently lower in R6/2 compared with WT muscle. The invariable R6/2 ClC-1 properties suggest a disruption in muscle maturation, which we confirm by measuring elevated levels of neonatal myosin heavy chain (MyHC) in late-stage R6/2 skeletal muscle. Similar changes in ClC-1 and MyHC isoforms in the more slowly developing Q175 HD mice suggest an altered maturational state is relevant to adult-onset HD. Finally, we find nuclear aggregates of muscleblind-like protein 1 without predominant CAG repeat colocalization in R6/2 muscle. This is unlike myotonic dystrophy, another trinucleotide repeat disorder with similar ClC-1 defects, and suggests a novel mechanism of aberrant mRNA splicing in HD. These early and progressive skeletal muscle defects reveal much needed peripheral biomarkers of disease progression and better elucidate the mechanism underlying HD myopathy.
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Affiliation(s)
- Daniel R Miranda
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768.,Department of Biological Sciences, Wright State University, Dayton, OH 45435
| | - Monica Wong
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768
| | - Shannon H Romer
- Department of Biological Sciences, Wright State University, Dayton, OH 45435
| | - Cynthia McKee
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768
| | - Gabriela Garza-Vasquez
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768
| | - Alyssa C Medina
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768
| | - Volker Bahn
- Department of Biological Sciences, Wright State University, Dayton, OH 45435
| | - Andrew D Steele
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768
| | - Robert J Talmadge
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768
| | - Andrew A Voss
- Department of Biological Sciences, Wright State University, Dayton, OH 45435
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134
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La Rosa P, Bielli P, Compagnucci C, Cesari E, Volpe E, Farioli Vecchioli S, Sette C. Sam68 promotes self-renewal and glycolytic metabolism in mouse neural progenitor cells by modulating Aldh1a3 pre-mRNA 3'-end processing. eLife 2016; 5. [PMID: 27845622 PMCID: PMC5122457 DOI: 10.7554/elife.20750] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/14/2016] [Indexed: 12/20/2022] Open
Abstract
The balance between self-renewal and differentiation of neural progenitor cells (NPCs) dictates neurogenesis and proper brain development. We found that the RNA- binding protein Sam68 (Khdrbs1) is strongly expressed in neurogenic areas of the neocortex and supports the self-renewing potential of mouse NPCs. Knockout of Khdrbs1 constricted the pool of proliferating NPCs by accelerating their cell cycle exit and differentiation into post-mitotic neurons. Sam68 function was linked to regulation of Aldh1a3 pre-mRNA 3'-end processing. Binding of Sam68 to an intronic polyadenylation site prevents its recognition and premature transcript termination, favoring expression of a functional enzyme. The lower ALDH1A3 expression and activity in Khdrbs1-/- NPCs results in reduced glycolysis and clonogenicity, thus depleting the embryonic NPC pool and limiting cortical expansion. Our study identifies Sam68 as a key regulator of NPC self-renewal and establishes a novel link between modulation of ALDH1A3 expression and maintenance of high glycolytic metabolism in the developing cortex. DOI:http://dx.doi.org/10.7554/eLife.20750.001 Neurons develop from cells called neural progenitors. These cells can either divide to produce more progenitor cells or develop into specific types of neurons. These two activities – known as self-renewal and differentiation – must be balanced to produce the right number of specialized neurons, without depleting the pool of progenitor cells. The self-renewal and differentiation of progenitor cells is balanced by essentially regulating which genes are active, or expressed, within the cells. In the first step of gene expression, the genetic instructions are copied to form a molecule of pre-messenger RNA (or pre-mRNA for short). Each pre-mRNA molecule is then processed to produce a final product that can be translated into protein. Importantly, two copies of the same pre-mRNA may sometimes be processed in different ways, which allows multiple proteins to be produced from a single gene. RNA-binding proteins control pre-mRNA processing. The expression of one such protein, called Sam68, oscillates during the development of the nervous system, such that its expression peaks when there is intense production of new neurons and then declines. However, it was not known whether Sam68 actually helps neurons to develop. La Rosa et al. have now analysed the role of Sam68 in the developing brain of mice. The experiments confirmed that Sam68 is highly expressed in neural progenitor cells and showed that its levels dictate the cell’s fate: high expression encourages a cell to self-renew, while low expression triggers it to develop into a specialized neuron. Further investigation revealed that Sam68 works by promoting the expression of a metabolic enzyme called Aldehyde Dehydrogenase 1A3 or ALDH1A3. This enzyme promotes the release of energy from molecules of glucose via a process known as anaerobic glycolysis. La Rosa et al. found that cells that lack Sam68 make a truncated version of the pre-mRNA encoding ALDH1A3. This truncated pre-mRNA encodes a shortened version of the enzyme that is inactive. Further experiments confirmed that Sam68 normally prevents this from happening by binding to the pre-mRNA and processing it to produce the full-length, working version of the ALDH1A3 enzyme. Also, La Rosa et al. found that progenitor cells need working ALDH1A3 to keep them dividing, and to stop them from developing into specialized neurons too soon. Finally, because the processing of pre-RNA plays a major role in brain development, problems with this process often lead to intellectual disabilities and neurodegenerative diseases, such as autism spectrum disorder and amyotrophic lateral sclerosis. The next step following on from these new findings will be to investigate whether defects in Sam68 contribute to such conditions and, if so, to look for ways to counteract these defects. DOI:http://dx.doi.org/10.7554/eLife.20750.002
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Affiliation(s)
- Piergiorgio La Rosa
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, Rome, Italy
| | - Pamela Bielli
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, Rome, Italy
| | - Claudia Compagnucci
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, Rome, Italy
| | - Eleonora Cesari
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, Rome, Italy
| | - Elisabetta Volpe
- Laboratory of Neuroimmunology, Fondazione Santa Lucia, Rome, Italy
| | | | - Claudio Sette
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.,Laboratory of Neuroembryology, Fondazione Santa Lucia, Rome, Italy
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135
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Yang WY, He F, Strack RL, Oh SY, Frazer M, Jaffrey SR, Todd PK, Disney MD. Small Molecule Recognition and Tools to Study Modulation of r(CGG)(exp) in Fragile X-Associated Tremor Ataxia Syndrome. ACS Chem Biol 2016; 11:2456-65. [PMID: 27276216 DOI: 10.1021/acschembio.6b00147] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
RNA transcripts containing expanded nucleotide repeats cause many incurable diseases via various mechanisms. One such disorder, fragile X-associated tremor ataxia syndrome (FXTAS), is caused by a noncoding r(CGG) repeat expansion (r(CGG)(exp)) that (i) sequesters proteins involved in RNA metabolism in nuclear foci, causing dysregulation of alternative pre-mRNA splicing, and (ii) undergoes repeat associated non-ATG translation (RANT), which produces toxic homopolymeric proteins without using a start codon. Here, we describe the design of two small molecules that inhibit both modes of toxicity and the implementation of various tools to study perturbation of these cellular events. Competitive Chemical Cross Linking and Isolation by Pull Down (C-Chem-CLIP) established that compounds bind r(CGG)(exp) and defined small molecule occupancy of r(CGG)(exp) in cells, the first approach to do so. Using an RNA GFP mimic, r(CGG)(exp)-Spinach2, we observe that our optimal designed compound binds r(CGG)(exp) and affects RNA localization by disrupting preformed RNA foci. These events correlate with an improvement of pre-mRNA splicing defects caused by RNA gain of function. In addition, the compounds reduced levels of toxic homopolymeric proteins formed via RANT. Polysome profiling studies showed that small molecules decreased loading of polysomes onto r(CGG)(exp), explaining decreased translation.
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Affiliation(s)
- Wang-Yong Yang
- Departments
of Chemistry and Neuroscience, The Scripps Research Institute, 130
Scripps Way, Jupiter, Florida 33458, United States
| | - Fang He
- Department
of Neurology, University of Michigan, 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, Michigan 48109-2200, United States
| | - Rita L. Strack
- Department
of Pharmacology, Weill Medical College of Cornell University, 1300
York Avenue, Box 70, New York, New York 10065, United States
| | - Seok Yoon Oh
- Department
of Neurology, University of Michigan, 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, Michigan 48109-2200, United States
| | - Michelle Frazer
- Department
of Neurology, University of Michigan, 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, Michigan 48109-2200, United States
| | - Samie R. Jaffrey
- Department
of Pharmacology, Weill Medical College of Cornell University, 1300
York Avenue, Box 70, New York, New York 10065, United States
| | - Peter K. Todd
- Department
of Neurology, University of Michigan, 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, Michigan 48109-2200, United States
| | - Matthew D. Disney
- Departments
of Chemistry and Neuroscience, The Scripps Research Institute, 130
Scripps Way, Jupiter, Florida 33458, United States
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136
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Jazurek M, Ciesiolka A, Starega-Roslan J, Bilinska K, Krzyzosiak WJ. Identifying proteins that bind to specific RNAs - focus on simple repeat expansion diseases. Nucleic Acids Res 2016; 44:9050-9070. [PMID: 27625393 PMCID: PMC5100574 DOI: 10.1093/nar/gkw803] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 09/01/2016] [Indexed: 12/11/2022] Open
Abstract
RNA–protein complexes play a central role in the regulation of fundamental cellular processes, such as mRNA splicing, localization, translation and degradation. The misregulation of these interactions can cause a variety of human diseases, including cancer and neurodegenerative disorders. Recently, many strategies have been developed to comprehensively analyze these complex and highly dynamic RNA–protein networks. Extensive efforts have been made to purify in vivo-assembled RNA–protein complexes. In this review, we focused on commonly used RNA-centric approaches that involve mass spectrometry, which are powerful tools for identifying proteins bound to a given RNA. We present various RNA capture strategies that primarily depend on whether the RNA of interest is modified. Moreover, we briefly discuss the advantages and limitations of in vitro and in vivo approaches. Furthermore, we describe recent advances in quantitative proteomics as well as the methods that are most commonly used to validate robust mass spectrometry data. Finally, we present approaches that have successfully identified expanded repeat-binding proteins, which present abnormal RNA–protein interactions that result in the development of many neurological diseases.
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Affiliation(s)
- Magdalena Jazurek
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Adam Ciesiolka
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Julia Starega-Roslan
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Katarzyna Bilinska
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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Loesch DZ, Annesley SJ, Trost N, Bui MQ, Lay ST, Storey E, De Piazza SW, Sanislav O, Francione LM, Hammersley EM, Tassone F, Francis D, Fisher PR. Novel Blood Biomarkers Are Associated with White Matter Lesions in Fragile X- Associated Tremor/Ataxia Syndrome. NEURODEGENER DIS 2016; 17:22-30. [PMID: 27602566 PMCID: PMC10964908 DOI: 10.1159/000446803] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/13/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The need for accessible cellular biomarkers of neurodegeneration in carriers of the fragile X mental retardation 1 (FMR1) premutation (PM) alleles. OBJECTIVE To assess the mitochondrial status and respiration in blood lymphoblasts from PM carriers manifesting the fragile X-associated tremor/ataxia syndrome (FXTAS) and non-FXTAS carriers, and their relationship with the brain white matter lesions. METHODS Oxygen consumption rates (OCR) and ATP synthesis using a Seahorse XFe24 Extracellular Flux Analyser, and steady-state parameters of mitochondrial function were assessed in cultured lymphoblasts from 16 PM males (including 11 FXTAS patients) and 9 matched controls. The regional white matter hyperintensity (WMH) scores were obtained from MRI. RESULTS Mitochondrial respiratory activity was significantly elevated in lymphoblasts from PM carriers compared with controls, with a 2- to 3-fold increase in basal and maximum OCR attributable to complex I activity, and ATP synthesis, accompanied by unaltered mitochondrial mass and membrane potential. The changes, which were more advanced in FXTAS patients, were significantly associated with the WMH scores in the supratentorial regions. CONCLUSION The dramatic increase in mitochondrial activity in lymphoblasts from PM carriers may represent either the early stages of disease (specific alterations in short-lived blood cells) or an activation of the lymphocytes under pathological situations. These changes may provide early, convenient blood biomarkers of clinical involvements.
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Affiliation(s)
- Danuta Z. Loesch
- Department of Psychology and Counselling, School of Psychology and Public Health, Melbourne, Vic., Australia
| | - Sarah J. Annesley
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, College of Science Health and Engineering, La Trobe University, Melbourne, Vic., Australia
| | - Nicholas Trost
- Medical Imaging Department, St Vincent's Hospital, Melbourne, Vic., Australia
| | - Minh Q. Bui
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Vic., Australia
| | - Sui T. Lay
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, College of Science Health and Engineering, La Trobe University, Melbourne, Vic., Australia
| | - Elsdon Storey
- Department of Medicine (Neuroscience), Monash University (Alfred Hospital Campus), Melbourne, Vic., Australia
| | - Shawn W. De Piazza
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, College of Science Health and Engineering, La Trobe University, Melbourne, Vic., Australia
| | - Oana Sanislav
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, College of Science Health and Engineering, La Trobe University, Melbourne, Vic., Australia
| | - Lisa M. Francione
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, College of Science Health and Engineering, La Trobe University, Melbourne, Vic., Australia
| | - Eleanor M. Hammersley
- Department of Psychology and Counselling, School of Psychology and Public Health, Melbourne, Vic., Australia
| | | | - David Francis
- Cytomolecular Diagnostic Research, Victorian Clinical Genetic Services, Murdoch Institute, Royal Children's Hospital, Melbourne, Vic., Australia
| | - Paul R. Fisher
- Discipline of Microbiology, Department of Physiology Anatomy and Microbiology, School of Life Sciences, College of Science Health and Engineering, La Trobe University, Melbourne, Vic., Australia
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138
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Alaqeel AM, Abou Al-Shaar H, Shariff RK, Albakr A. The role of RNA metabolism in neurological diseases. Balkan J Med Genet 2016; 18:5-14. [PMID: 27785391 PMCID: PMC5026263 DOI: 10.1515/bjmg-2015-0080] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Neurodegenerative disorders are commonly encountered in medical practices. Such diseases can lead to major morbidity and mortality among the affected individuals. The molecular pathogenesis of these disorders is not yet clear. Recent literature has revealed that mutations in RNA-binding proteins are a key cause of several human neuronal-based diseases. This review discusses the role of RNA metabolism in neurological diseases with specific emphasis on roles of RNA translation and microRNAs in neurodegeneration, RNA-mediated toxicity, repeat expansion diseases and RNA metabolism, molecular pathogenesis of amyotrophic lateral sclerosis and frontotemporal dementia, and neurobiology of survival motor neuron (SMN) and spinal muscular atrophy.
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Affiliation(s)
- A M Alaqeel
- Department of Neurosurgery, University of Calgary, Calgary, Alberta, Canada; Division of Neurosurgery, Department of Surgery, King Saud University, Riyadh, Saudi Arabia
| | - H Abou Al-Shaar
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - R K Shariff
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - A Albakr
- Division of Neurosurgery, Department of Surgery, King Saud University, Riyadh, Saudi Arabia
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139
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Kumari D, Usdin K. Sustained expression of FMR1 mRNA from reactivated fragile X syndrome alleles after treatment with small molecules that prevent trimethylation of H3K27. Hum Mol Genet 2016; 25:3689-3698. [PMID: 27378697 DOI: 10.1093/hmg/ddw215] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 05/20/2016] [Accepted: 06/29/2016] [Indexed: 11/14/2022] Open
Abstract
Expansion of a CGG-repeat tract in the 5'-untranslated region of the FMR1 gene to >200 repeats results in epigenetic silencing of the gene by a mechanism that is still unknown. FMR1 gene silencing results in fragile X syndrome (FXS), the most common heritable cause of intellectual disability. We have previously shown that reactivation of the FMR1 gene in FXS cells with 5-azadeoxycytidine (AZA) leads to the transient recruitment of EZH2, the polycomb repressive complex 2 (PRC2) component responsible for H3K27 trimethylation, and that this recruitment depends on the presence of the FMR1 transcript. However, whether H3K27 trimethylation was essential for FMR1 re-silencing was not known. We show here that EZH2 inhibitors increased FMR1 expression and significantly delayed re-silencing of the FMR1 gene in AZA-treated FXS cells. This delay occurred despite the fact that EZH2 inhibition did not prevent the return of DNA methylation. Treatment with compound 1a, a small molecule that targets CGG-repeats in the FMR1 mRNA, also resulted in sustained expression of the FMR1 gene in AZA-treated cells. This effect of 1a was also associated with a decrease in the levels of H3K27 trimethylation but not DNA methylation. Thus, our data show that EZH2 plays a critical role in the FMR1 gene silencing process and that its inhibition can prolong expression of the FMR1 gene even in the presence of its transcript.
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Affiliation(s)
- Daman Kumari
- Section on Genomic Structure and Function, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Karen Usdin
- Section on Genomic Structure and Function, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
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140
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Song G, Napoli E, Wong S, Hagerman R, Liu S, Tassone F, Giulivi C. Altered redox mitochondrial biology in the neurodegenerative disorder fragile X-tremor/ataxia syndrome: use of antioxidants in precision medicine. Mol Med 2016; 22:548-559. [PMID: 27385396 DOI: 10.2119/molmed.2016.00122] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 06/23/2016] [Indexed: 11/06/2022] Open
Abstract
A 55-200 expansion of the CGG nucleotide repeat in the 5'-UTR of the fragile X mental retardation 1 gene (FMR1) is the hallmark of the triplet nucleotide disease known as the "premutation" as opposed to those with >200 repeats, known as the full mutation or fragile X syndrome. Originally, premutation carriers were thought to be free of phenotypic traits; however, some are diagnosed with emotional and neurocognitive issues and, later in life, with the neurodegenerative disease fragile X-associated tremor/ataxia syndrome (FXTAS). Considering that mitochondrial dysfunction has been observed in fibroblasts and post-mortem brain samples from carriers of the premutation, we hypothesized that mitochondrial dysfunction-derived ROS may result in cumulative oxidative-nitrative damage. Fibroblasts from premutation carriers (n=31, all FXTAS-free except 8), compared to age- and sex-matched controls (n=25), showed increased mitochondrial ROS production, impaired Complex I activity, lower expression of MIA40 (rate-limiting step of the redox-regulated mitochondrial-disulfide-relay-system), increased mtDNA deletions, and increased biomarkers of lipid and protein oxidative-nitrative damage. Most of the outcomes were more pronounced in FXTAS-affected individuals. Significant recovery of mitochondrial mass and/or function was obtained with superoxide or hydroxyl radicals' scavengers, a glutathione peroxidase analog, or by overexpressing MIA40. The effects of ethanol (a hydroxyl radical scavenger) were deleterious, while others (by N-acetyl-cysteine, quercetin and epigallocatechin-3-gallate) were outcome- and/or carrier-specifics. The use of antioxidants in the context of precision medicine is discussed with the goal of improving mitochondrial function in carriers with the potential of decreasing the morbidity and/or delaying FXTAS onset.
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Affiliation(s)
- Gyu Song
- Department of Molecular Biosciences, School of Veterinary Medicine, Davis, CA 95616
| | - Eleonora Napoli
- Department of Molecular Biosciences, School of Veterinary Medicine, Davis, CA 95616
| | - Sarah Wong
- Department of Molecular Biosciences, School of Veterinary Medicine, Davis, CA 95616
| | - Randi Hagerman
- Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, CA 95817.,Department of Pediatrics, University of California Davis Medical Center, Sacramento CA 95817
| | - Siming Liu
- Department of Molecular Biosciences, School of Veterinary Medicine, Davis, CA 95616
| | - Flora Tassone
- Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, CA 95817.,Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, CA 95817
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, Davis, CA 95616.,Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, CA 95817
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141
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Foote MM, Careaga M, Berman RF. What has been learned from mouse models of the Fragile X Premutation and Fragile X-associated tremor/ataxia syndrome? Clin Neuropsychol 2016; 30:960-72. [PMID: 27355912 DOI: 10.1080/13854046.2016.1158254] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To describe in this review how research using mouse models developed to study the Fragile X premutation (PM) and Fragile X-associated tremor/ataxia syndrome (FXTAS) have contributed to understanding these disorders. PM carriers bear an expanded CGG trinucleotide repeat on the Fragile X Mental Retardation 1 (FMR1) gene, and are at risk for developing the late onset neurodegenerative disorder FXTAS. CONCLUSIONS Much has been learned about these genetic disorders from the development and study of mouse models. This includes new insights into the early cellular and molecular events that occur in PM carriers and in FXTAS, the presence of multiorgan pathology beyond the CNS, immunological dysregulation, unexpected synthesis of a potentially toxic peptide in FXTAS (i.e., FMRpolyG), and evidence that the disease process may be halted or reversed by appropriate molecular therapies given early in the course of disease.
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Affiliation(s)
- Molly M Foote
- a Department of Neurological Surgery , University of California Davis , Davis , CA , USA
| | - Milo Careaga
- b Department of Psychiatry and UC Davis M.I.N.D. Institute , University of California Davis , Davis , CA , USA
| | - Robert F Berman
- c Department of Neurological Surgery and the UC Davis M.I.N.D. Institute , University of California Davis , Davis , CA , USA
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142
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Napoli E, Song G, Schneider A, Hagerman R, Eldeeb MAAA, Azarang A, Tassone F, Giulivi C. Warburg effect linked to cognitive-executive deficits in FMR1 premutation. FASEB J 2016; 30:3334-3351. [PMID: 27335370 DOI: 10.1096/fj.201600315r] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 06/14/2016] [Indexed: 11/11/2022]
Abstract
A 55-200 CGG repeat expansion in the 5'-UTR of the fragile X mental retardation 1 (FMR1) gene is known as a premutation. Some carriers are affected by the neurodegenerative disorder fragile X-associated tremor/ataxia syndrome (FXTAS), primary ovarian insufficiency, and neurobehavioral impairments. Based on the mitochondrial dysfunction observed in fibroblasts and brain samples from carriers, as well as in neurons and brains from a mouse model of the premutation, we evaluated the presence of the Warburg effect in peripheral blood mononuclear cells (PBMCs) from 30 premutation carriers with either a rebalance of the metabolism [increasing glycolysis while decreasing oxidative phosphorylation (oxphos)] or a metabolic amplification (increasing glycolysis while maintaining/increasing oxphos). Deficits in oxphos-more pronounced in FXTAS-affected subjects-were accompanied by a shift toward glycolysis, suggesting increased glycolysis despite aerobic conditions. Differential proteomics extended these findings, unveiling a decreased antioxidant response, translation, and disrupted extracellular matrix and cytoskeleton organization with activation of prosenescence pathways. Lower bioenergetics segregated with increased incidence of low executive function, tremors, below-average IQ, and FXTAS. The combination of functional and proteomic data unveiled new mechanisms related to energy production in the premutation, showing the potential of being applicable to other psychiatric disorders to identify endophenotype-specific responses relevant to neurobiology.-Napoli, E., Song, G., Schneider, A., Hagerman, R., Eldeeb, M. A. A. A., Azarang, A., Tassone, F., Giulivi, C. Warburg effect linked to cognitive-executive deficits in FMR1 premutation.
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Affiliation(s)
- Eleonora Napoli
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Gyu Song
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Andrea Schneider
- Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis, Davis, California, USA; Department of Pediatrics, University of California Davis Medical Center, Sacramento California, USA; and
| | - Randi Hagerman
- Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis, Davis, California, USA; Department of Pediatrics, University of California Davis Medical Center, Sacramento California, USA; and
| | - Marwa Abd Al Azaim Eldeeb
- Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis, Davis, California, USA
| | - Atoosa Azarang
- Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis, Davis, California, USA
| | - Flora Tassone
- Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California, Davis, Davis, California, USA; Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, California, USA
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, California, USA; Department of Pediatrics, University of California Davis Medical Center, Sacramento California, USA; and
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143
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Molecular Pathophysiology of Fragile X-Associated Tremor/Ataxia Syndrome and Perspectives for Drug Development. THE CEREBELLUM 2016; 15:599-610. [DOI: 10.1007/s12311-016-0800-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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144
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Urbanek MO, Jazurek M, Switonski PM, Figura G, Krzyzosiak WJ. Nuclear speckles are detention centers for transcripts containing expanded CAG repeats. Biochim Biophys Acta Mol Basis Dis 2016; 1862:1513-20. [PMID: 27239700 DOI: 10.1016/j.bbadis.2016.05.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/18/2016] [Accepted: 05/26/2016] [Indexed: 12/13/2022]
Abstract
The human genetic disorders caused by CAG repeat expansions in the translated sequences of various genes are called polyglutamine (polyQ) diseases because of the cellular "toxicity" of the mutant proteins. The contribution of mutant transcripts to the pathogenesis of these diseases is supported by several observations obtained from cellular models of these disorders. Here, we show that the common feature of cell lines modeling polyQ diseases is the formation of nuclear CAG RNA foci. We performed qualitative and quantitative analyses of these foci in numerous cellular models endogenously and exogenously expressing mutant transcripts by fluorescence in situ hybridization (FISH). We compared the CAG RNA foci of polyQ diseases with the CUG foci of myotonic dystrophy type 1 and found substantial differences in their number and morphology. Smaller differences within the polyQ disease group were also revealed and included a positive correlation between the foci number and the CAG repeat length. We show that expanded CAA repeats, also encoding glutamine, did not trigger RNA foci formation and foci formation is independent of the presence of mutant polyglutamine protein. Using FISH combined with immunofluorescence, we demonstrated partial co-localization of CAG repeat foci with MBNL1 alternative splicing factor, which explains the mild deregulation of MBNL1-dependent genes. We also showed that foci reside within nuclear speckles in diverse cell types: fibroblasts, lymphoblasts, iPS cells and neuronal progenitors and remain dependent on integrity of these nuclear structures.
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Affiliation(s)
- Martyna O Urbanek
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland
| | - Magdalena Jazurek
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland
| | - Pawel M Switonski
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland
| | - Grzegorz Figura
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland.
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Napoli E, Ross-Inta C, Song G, Wong S, Hagerman R, Gane LW, Smilowitz JT, Tassone F, Giulivi C. Premutation in the Fragile X Mental Retardation 1 (FMR1) Gene Affects Maternal Zn-milk and Perinatal Brain Bioenergetics and Scaffolding. Front Neurosci 2016; 10:159. [PMID: 27147951 PMCID: PMC4835505 DOI: 10.3389/fnins.2016.00159] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 03/29/2016] [Indexed: 12/12/2022] Open
Abstract
Fragile X premutation alleles have 55–200 CGG repeats in the 5′ UTR of the FMR1 gene. Altered zinc (Zn) homeostasis has been reported in fibroblasts from >60 years old premutation carriers, in which Zn supplementation significantly restored Zn-dependent mitochondrial protein import/processing and function. Given that mitochondria play a critical role in synaptic transmission, brain function, and cognition, we tested FMRP protein expression, brain bioenergetics, and expression of the Zn-dependent synaptic scaffolding protein SH3 and multiple ankyrin repeat domains 3 (Shank3) in a knock-in (KI) premutation mouse model with 180 CGG repeats. Mitochondrial outcomes correlated with FMRP protein expression (but not FMR1 gene expression) in KI mice and human fibroblasts from carriers of the pre- and full-mutation. Significant deficits in brain bioenergetics, Zn levels, and Shank3 protein expression were observed in the Zn-rich regions KI hippocampus and cerebellum at PND21, with some of these effects lasting into adulthood (PND210). A strong genotype × age interaction was observed for most of the outcomes tested in hippocampus and cerebellum, whereas in cortex, age played a major role. Given that the most significant effects were observed at the end of the lactation period, we hypothesized that KI milk might have a role at compounding the deleterious effects on the FMR1 genetic background. A higher gene expression of ZnT4 and ZnT6, Zn transporters abundant in brain and lactating mammary glands, was observed in the latter tissue of KI dams. A cross-fostering experiment allowed improving cortex bioenergetics in KI pups nursing on WT milk. Conversely, WT pups nursing on KI milk showed deficits in hippocampus and cerebellum bioenergetics. A highly significant milk type × genotype interaction was observed for all three-brain regions, being cortex the most influenced. Finally, lower milk-Zn levels were recorded in milk from lactating women carrying the premutation as well as other Zn-related outcomes (Zn-dependent alkaline phosphatase activity and lactose biosynthesis—whose limiting step is the Zn-dependent β-1,4-galactosyltransferase). In premutation carriers, altered Zn homeostasis, brain bioenergetics and Shank3 levels could be compounded by Zn-deficient milk, increasing the risk of developing emotional and neurological/cognitive problems and/or FXTAS later in life.
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Affiliation(s)
- Eleonora Napoli
- Department of Molecular Biosciences, School of Veterinary Medicine Davis, CA, USA
| | - Catherine Ross-Inta
- Department of Molecular Biosciences, School of Veterinary Medicine Davis, CA, USA
| | - Gyu Song
- Department of Molecular Biosciences, School of Veterinary Medicine Davis, CA, USA
| | - Sarah Wong
- Department of Molecular Biosciences, School of Veterinary Medicine Davis, CA, USA
| | - Randi Hagerman
- Medical Investigations of Neurodevelopmental Disorders Institute, University of California, DavisDavis, CA, USA; Department of Pediatrics, University of California Davis Medical CenterSacramento, CA, USA
| | - Louise W Gane
- Medical Investigations of Neurodevelopmental Disorders Institute, University of California, Davis Davis, CA, USA
| | - Jennifer T Smilowitz
- Department of Food Science and Technology and Foods for Health Institute, University of California, Davis Davis, CA, USA
| | - Flora Tassone
- Medical Investigations of Neurodevelopmental Disorders Institute, University of California, DavisDavis, CA, USA; Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, DavisDavis, CA, USA
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary MedicineDavis, CA, USA; Medical Investigations of Neurodevelopmental Disorders Institute, University of California, DavisDavis, CA, USA
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Conca Dioguardi C, Uslu B, Haynes M, Kurus M, Gul M, Miao DQ, De Santis L, Ferrari M, Bellone S, Santin A, Giulivi C, Hoffman G, Usdin K, Johnson J. Granulosa cell and oocyte mitochondrial abnormalities in a mouse model of fragile X primary ovarian insufficiency. Mol Hum Reprod 2016; 22:384-96. [PMID: 26965313 DOI: 10.1093/molehr/gaw023] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/04/2016] [Indexed: 11/13/2022] Open
Abstract
STUDY HYPOTHESIS We hypothesized that the mitochondria of granulosa cells (GC) and/or oocytes might be abnormal in a mouse model of fragile X premutation (FXPM). STUDY FINDING Mice heterozygous and homozygous for the FXPM have increased death (atresia) of large ovarian follicles, fewer corpora lutea with a gene dosage effect manifesting in decreased litter size(s). Furthermore, granulosa cells (GC) and oocytes of FXPM mice have decreased mitochondrial content, structurally abnormal mitochondria, and reduced expression of critical mitochondrial genes. Because this mouse allele produces the mutant Fragile X mental retardation 1 (Fmr1) transcript and reduced levels of wild-type (WT) Fmr1 protein (FMRP), but does not produce a Repeat Associated Non-ATG Translation (RAN)-translation product, our data lend support to the idea that Fmr1 mRNA with large numbers of CGG-repeats is intrinsically deleterious in the ovary. WHAT IS KNOWN ALREADY Mitochondrial dysfunction has been detected in somatic cells of human and mouse FX PM carriers and mitochondria are essential for oogenesis and ovarian follicle development, FX-associated primary ovarian insufficiency (FXPOI) is seen in women with FXPM alleles. These alleles have 55-200 CGG repeats in the 5' UTR of an X-linked gene known as FMR1. The molecular basis of the pathology seen in this disorder is unclear but is thought to involve either some deleterious consequence of overexpression of RNA with long CGG-repeat tracts or of the generation of a repeat-associated non-AUG translation (RAN translation) product that is toxic. STUDY DESIGN, SAMPLES/MATERIALS, METHODS Analysis of ovarian function in a knock-in FXPM mouse model carrying 130 CGG repeats was performed as follows on WT, PM/+, and PM/PM genotypes. Histomorphometric assessment of follicle and corpora lutea numbers in ovaries from 8-month-old mice was executed, along with litter size analysis. Mitochondrial DNA copy number was quantified in oocytes and GC using quantitative PCR, and cumulus granulosa mitochondrial content was measured by flow cytometric analysis after staining of cells with Mitotracker dye. Transmission electron micrographs were prepared of GC within small growing follicles and mitochondrial architecture was compared. Quantitative RT-PCR analysis of key genes involved in mitochondrial structure and recycling was performed. MAIN RESULTS AND THE ROLE OF CHANCE A defect was found in follicle survival at the large antral stage in PM/+ and PM/PM mice. Litter size was significantly decreased in PM/PM mice, and corpora lutea were significantly reduced in mice of both mutant genotypes. Mitochondrial DNA copy number was significantly decreased in GC and metaphase II eggs in mutants. Flow cytometric analysis revealed that PM/+ and PM/PM animals lack the cumulus GC that harbor the greatest mitochondrial content as found in wild-type animals. Electron microscopic evaluation of GC of small growing follicles revealed mitochondrial structural abnormalities, including disorganized and vacuolar cristae. Finally, aberrant mitochondrial gene expression was detected. Mitofusin 2 (Mfn2) and Optic atrophy 1 (Opa1), genes involved in mitochondrial fusion and structure, respectively, were significantly decreased in whole ovaries of both mutant genotypes. Mitochondrial fission factor 1 (Mff1) was significantly decreased in PM/+ and PM/PM GC and eggs compared with wild-type controls. LIMITATIONS, REASONS FOR CAUTION Data from the mouse model used for these studies should be viewed with some caution when considering parallels to the human FXPOI condition. WIDER IMPLICATIONS OF THE FINDINGS Our data lend support to the idea that Fmr1 mRNA with large numbers of CGG-repeats is intrinsically deleterious in the ovary. FXPM disease states, including FXPOI, may share mitochondrial dysfunction as a common underlying mechanism. LARGE SCALE DATA Not applicable. STUDY FUNDING AND COMPETING INTERESTS Studies were supported by NIH R21 071873 (J.J./G.H), The Albert McKern Fund for Perinatal Research (J.J.), NIH Intramural Funds (K.U.), and a TUBITAK Research Fellowship Award (B.U.). No conflict(s) of interest or competing interest(s) are noted.
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Affiliation(s)
- Carola Conca Dioguardi
- Department of Obstetrics, Gynecology, & Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA Division of Reproductive Endocrinology and Infertility, Yale School of Medicine, New Haven, CT, USA Vita-Salute San Raffaele University/IRCCS San Raffaele Hospital, Milan, Italy
| | - Bahar Uslu
- Department of Obstetrics, Gynecology, & Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA Division of Reproductive Endocrinology and Infertility, Yale School of Medicine, New Haven, CT, USA
| | - Monique Haynes
- Department of Obstetrics, Gynecology, & Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA Division of Reproductive Endocrinology and Infertility, Yale School of Medicine, New Haven, CT, USA
| | - Meltem Kurus
- Department of Histology & Embryology, Izmir Katip Celebi University School of Medicine, Izmir, Turkey
| | - Mehmet Gul
- Department of Histology & Embryology, Inonu University School of Medicine, Malatya, Turkey
| | - De-Qiang Miao
- Department of Obstetrics, Gynecology, & Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA Division of Reproductive Endocrinology and Infertility, Yale School of Medicine, New Haven, CT, USA
| | - Lucia De Santis
- Department of Obstetrics & Gynecology, IVF Unit, Vita-Salute San Raffaele University/IRCCS San Raffaele Hospital, Milan, Italy
| | - Maurizio Ferrari
- Laboratory of Clinical Molecular Biology and Cytogenetics, Vita-Salute San Raffaele University/IRCCS San Raffaele Hospital, Milan, Italy
| | - Stefania Bellone
- Department of Obstetrics, Gynecology, & Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA Division of Gynecologic Oncology, Yale School of Medicine, New Haven, CT, USA
| | - Alessandro Santin
- Department of Obstetrics, Gynecology, & Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA Division of Gynecologic Oncology, Yale School of Medicine, New Haven, CT, USA
| | - Cecilia Giulivi
- Department of Molecular Biosciences, M.I.N.D. Institute, University of California-Davis, Davis, CA, USA
| | - Gloria Hoffman
- Department of Biology, Morgan State University, Baltimore, MD, USA
| | - Karen Usdin
- Laboratory of Cellular and Molecular Biology, NIH/NIDDK, Bethesda, MD, USA
| | - Joshua Johnson
- Department of Obstetrics, Gynecology, & Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA Division of Reproductive Endocrinology and Infertility, Yale School of Medicine, New Haven, CT, USA
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147
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Proteostasis and RNA Binding Proteins in Synaptic Plasticity and in the Pathogenesis of Neuropsychiatric Disorders. Neural Plast 2016; 2016:3857934. [PMID: 26904297 PMCID: PMC4745388 DOI: 10.1155/2016/3857934] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/30/2015] [Indexed: 12/30/2022] Open
Abstract
Decades of research have demonstrated that rapid alterations in protein abundance are required for synaptic plasticity, a cellular correlate for learning and memory. Control of protein abundance, known as proteostasis, is achieved across a complex neuronal morphology that includes a tortuous axon as well as an extensive dendritic arbor supporting thousands of individual synaptic compartments. To regulate the spatiotemporal synthesis of proteins, neurons must efficiently coordinate the transport and metabolism of mRNAs. Among multiple levels of regulation, transacting RNA binding proteins (RBPs) control proteostasis by binding to mRNAs and mediating their transport and translation in response to synaptic activity. In addition to synthesis, protein degradation must be carefully balanced for optimal proteostasis, as deviations resulting in excess or insufficient abundance of key synaptic factors produce pathologies. As such, mutations in components of the proteasomal or translational machinery, including RBPs, have been linked to the pathogenesis of neurological disorders such as Fragile X Syndrome (FXS), Fragile X Tremor Ataxia Syndrome (FXTAS), and Autism Spectrum Disorders (ASD). In this review, we summarize recent scientific findings, highlight ongoing questions, and link basic molecular mechanisms to the pathogenesis of common neuropsychiatric disorders.
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Elizur SE, Dratviman-Storobinsky O, Derech-Haim S, Lebovitz O, Dor J, Orvieto R, Cohen Y. FMR6 may play a role in the pathogenesis of fragile X-associated premature ovarian insufficiency. Gynecol Endocrinol 2016; 32:334-7. [PMID: 26652047 DOI: 10.3109/09513590.2015.1116508] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The aim of this study was to evaluate whether long noncoding RNA accumulation play a role in the pathophysiology of fragile X-associated premature ovarian insufficiency (FXPOI). The study population consisted of 22 consecutive fragile X mental retardation 1 (FMR1) premutation carriers (CGGn 55-199 repeats) undergoing in vitro fertilization and pre-implantation genetic diagnosis (IVF-PGD) treatment. The control group consists of 11 patients, with <55 CGG repeats, undergoing IVF-ICSI for male factor infertility, matched by age, treated in the same period. After oocyte retrieval, granulosa cells from follicular fluid were washed and stored at -80 °C. RNA was transcribed to generate cDNA and the RNA levels were measured using RT-PCR. Transcripts levels in granulosa cells of long noncoding RNA's FMR4 and FMR6 were measured. In FMR1 premutation carriers there was a significant nonlinear association between the number of CGG repeats and the levels of FMR6 (p = 0.03), but not FMR4. The highest level of FMR6 was seen in women with mid-size CGG repeats (80-120). In addition, a significant negative linear correlation was observed between the number of oocytes retrieved and the RNA levels in granulosa cells of FMR6 (r = -0.53, p = 0.01) but not FMR4. Our study supports previous findings suggesting RNA toxic gain-of-function as one of the possible pathophysiologic mechanisms underlying FXPOI.
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Affiliation(s)
- Shai E Elizur
- a IVF Unit, Department of Obstetrics and Gynecology , Chaim Sheba Medical Center , (Tel Hashomer) , Ramat Gan , Israel and
- b Sackler Faculty of Medicine , Tel Aviv University , Tel Aviv , Israel
| | - Olga Dratviman-Storobinsky
- a IVF Unit, Department of Obstetrics and Gynecology , Chaim Sheba Medical Center , (Tel Hashomer) , Ramat Gan , Israel and
- b Sackler Faculty of Medicine , Tel Aviv University , Tel Aviv , Israel
| | - Sanaz Derech-Haim
- a IVF Unit, Department of Obstetrics and Gynecology , Chaim Sheba Medical Center , (Tel Hashomer) , Ramat Gan , Israel and
- b Sackler Faculty of Medicine , Tel Aviv University , Tel Aviv , Israel
| | - Oshrit Lebovitz
- a IVF Unit, Department of Obstetrics and Gynecology , Chaim Sheba Medical Center , (Tel Hashomer) , Ramat Gan , Israel and
- b Sackler Faculty of Medicine , Tel Aviv University , Tel Aviv , Israel
| | - Jehoshua Dor
- a IVF Unit, Department of Obstetrics and Gynecology , Chaim Sheba Medical Center , (Tel Hashomer) , Ramat Gan , Israel and
- b Sackler Faculty of Medicine , Tel Aviv University , Tel Aviv , Israel
| | - Raoul Orvieto
- a IVF Unit, Department of Obstetrics and Gynecology , Chaim Sheba Medical Center , (Tel Hashomer) , Ramat Gan , Israel and
- b Sackler Faculty of Medicine , Tel Aviv University , Tel Aviv , Israel
| | - Yoram Cohen
- a IVF Unit, Department of Obstetrics and Gynecology , Chaim Sheba Medical Center , (Tel Hashomer) , Ramat Gan , Israel and
- b Sackler Faculty of Medicine , Tel Aviv University , Tel Aviv , Israel
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149
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The Working Modules of Long Noncoding RNAs in Cancer Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 927:49-67. [PMID: 27376731 DOI: 10.1007/978-981-10-1498-7_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
It is clear that RNA is more than just a messenger between gene and protein. The mammalian genome is pervasively transcribed, giving rise to tens of thousands of noncoding transcripts, especially long noncoding RNAs (lncRNAs). Whether all of these large transcripts are functional remains to be elucidated, but it is evident that there are many lncRNAs that seem not to be the "noise" of the transcriptome. Recent studies have set out to decode the regulatory role and functional diversity of lncRNAs in human physiological and pathological processes, and accumulating evidence suggests that most of the functional lncRNAs achieve their biological functions by controlling gene expression. In this chapter, we will organize these studies to provide a detailed description of the involvement of lncRNAs in the major steps of gene expression that include epigenetic regulation, RNA transcription, posttranscriptional RNA processing, protein translation, and posttranslational protein modification and highlight the molecular mechanisms through which lncRNAs function, involving the interactions between lncRNAs and other biological macromolecules.
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150
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Buijsen RAM, Visser JA, Kramer P, Severijnen EAWFM, Gearing M, Charlet-Berguerand N, Sherman SL, Berman RF, Willemsen R, Hukema RK. Presence of inclusions positive for polyglycine containing protein, FMRpolyG, indicates that repeat-associated non-AUG translation plays a role in fragile X-associated primary ovarian insufficiency. Hum Reprod 2015; 31:158-68. [PMID: 26537920 DOI: 10.1093/humrep/dev280] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/15/2015] [Indexed: 12/11/2022] Open
Abstract
STUDY QUESTION Does repeat-associated non-AUG (RAN) translation play a role in fragile X-associated primary ovarian insufficiency (FXPOI), leading to the presence of polyglycine containing protein (FMRpolyG)-positive inclusions in ovarian tissue? SUMMARY ANSWER Ovaries of a woman with FXPOI and of an Fmr1 premutation (PM) mouse model (exCGG-KI) contain intranuclear inclusions that stain positive for both FMRpolyG and ubiquitin. WHAT IS KNOWN ALREADY Women who carry the FMR1 PM are at 20-fold increased risk to develop primary ovarian insufficiency (FXPOI). A toxic RNA gain-of-function has been suggested as the underlying mechanism since the PM results in increased levels of mRNA containing an expanded repeat, but reduced protein levels of fragile X mental retardation protein (FMRP). Recently, RAN translation has been shown to occur from FMR1 mRNA that contains PM repeat expansions, leading to FMRpolyG inclusions in brain and non-CNS tissues of fragile X-associated tremor/ataxia syndrome (FXTAS) patients. STUDY DESIGN, SIZE, DURATION Ovaries of a woman with FXPOI and women without PM (controls), and ovaries from wild-type and exCGG-KI mice were analyzed by immunohistochemistry for the presence of inclusions that stained for ubiquitin and FMRpolyG . The ovaries from wild-type and exCGG-KI mice were further characterized for the number of follicles, Fmr1 mRNA levels and FMRP protein expression. The presence of inclusions was also analyzed in pituitaries of a man with FXTAS and the exCGG-KI mice. PARTICIPANTS/MATERIALS, SETTING, METHODS Human ovaries from a woman with FXPOI and two control subjects and pituitaries from a man with FXTAS and a control subjects were fixed in 4% formalin. Ovaries and pituitaries of wild-type and exCGG mice were fixed in Bouin's fluid or 4% paraformaldehyde. Immunohistochemistry was performed on the human and mouse samples using FMRpolyG, ubiquitin and Fmrp antibodies. Fmr1 mRNA and protein expression were determined in mouse ovaries by quantitative RT-PCR and Western blot analysis. Follicle numbers in mouse ovaries were determined in serial sections by microscopy. MAIN RESULTS AND THE ROLE OF CHANCE FMRpolyG-positive inclusions were present in ovarian stromal cells of a woman with FXPOI but not in the ovaries of control subjects. The FMRpolyG-positive inclusions colocalized with ubiquitin-positive inclusions. Similar inclusions were also observed in the pituitary of a man with FXTAS but not in control subjects. Similarly, ovaries of 40-week-old exCGG-KI mice, but not wild-type mice, contained numerous inclusions in the stromal cells that stained for both FMRpolyG- and ubiquitin, while the ovaries of 20-week-old exCGG-KI contained fewer inclusions. At 40 weeks ovarian Fmr1 mRNA expression was increased by 5-fold in exCGG-KI mice compared with wild-type mice, while Fmrp expression was reduced by 2-fold. With respect to ovarian function in exCGG-KI mice: (i) although the number of healthy growing follicles did not differ between wild-type and exCGG-KI mice, the number of atretic large antral follicles was increased by nearly 9-fold in 40-week old exCGG-KI mice (P < 0.001); (ii) at 40 weeks of age only 50% of exCGG-KI mice had recent ovulations compared with 89% in wild-type mice (P = 0.07) and (iii) those exCGG-KI mice with recent ovulations tended to have a reduced number of fresh corpora lutea (4.8 ± 1.74 versus 8.50 ± 0.98, exCGG-KI versus wild-type mice, respectively, P = 0.07). LIMITATIONS, REASONS FOR CAUTION Although FMRpolyG-positive inclusions were detected in ovaries of both a woman with FXPOI and a mouse model of the FMR1 PM, we only analyzed one ovary from a FXPOI subject. Caution is needed to extrapolate these results to all women with the FMR1 PM. Furthermore, the functional consequence of FMRpolyG-positive inclusions in the ovaries for reproduction remains to be determined. WIDER IMPLICATIONS OF THE FINDINGS Our results suggest that a dysfunctional hypothalamic-pituitary-gonadal-axis may contribute to FXPOI in FMR1 PM carriers. STUDY FUNDING/COMPETING INTERESTS This study was supported by grants from NFXF, ZonMW, the Netherlands Brain Foundation and NIH. The authors have no conflict of interest to declare.
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Affiliation(s)
- R A M Buijsen
- Department of Clinical Genetics, Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands
| | - J A Visser
- Department of Internal Medicine, Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands
| | - P Kramer
- Department of Internal Medicine, Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands
| | - E A W F M Severijnen
- Department of Clinical Genetics, Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands
| | - M Gearing
- Department of Pathology, Emory University School of Medicine, Atlanta, GA, USA
| | - N Charlet-Berguerand
- Department of Neurobiology and Genetics, IGBMC, INSERM U964, CNRS UMR7104, University of Strasbourg, Illkirch, France
| | - S L Sherman
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - R F Berman
- Department of Neurological Surgery, UC Davis, Davis 95618, CA, USA
| | - R Willemsen
- Department of Clinical Genetics, Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands
| | - R K Hukema
- Department of Clinical Genetics, Erasmus Medical Center, 3015 CE Rotterdam, The Netherlands
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