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Mukherjee S, Poudyal M, Dave K, Kadu P, Maji SK. Protein misfolding and amyloid nucleation through liquid-liquid phase separation. Chem Soc Rev 2024; 53:4976-5013. [PMID: 38597222 DOI: 10.1039/d3cs01065a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Liquid-liquid phase separation (LLPS) is an emerging phenomenon in cell physiology and diseases. The weak multivalent interaction prerequisite for LLPS is believed to be facilitated through intrinsically disordered regions, which are prevalent in neurodegenerative disease-associated proteins. These aggregation-prone proteins also exhibit an inherent property for phase separation, resulting in protein-rich liquid-like droplets. The very high local protein concentration in the water-deficient confined microenvironment not only drives the viscoelastic transition from the liquid to solid-like state but also most often nucleate amyloid fibril formation. Indeed, protein misfolding, oligomerization, and amyloid aggregation are observed to be initiated from the LLPS of various neurodegeneration-related proteins. Moreover, in these cases, neurodegeneration-promoting genetic and environmental factors play a direct role in amyloid aggregation preceded by the phase separation. These cumulative recent observations ignite the possibility of LLPS being a prominent nucleation mechanism associated with aberrant protein aggregation. The present review elaborates on the nucleation mechanism of the amyloid aggregation pathway and the possible early molecular events associated with amyloid-related protein phase separation. It also summarizes the recent advancement in understanding the aberrant phase transition of major proteins contributing to neurodegeneration focusing on the common disease-associated factors. Overall, this review proposes a generic LLPS-mediated multistep nucleation mechanism for amyloid aggregation and its implication in neurodegeneration.
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Affiliation(s)
- Semanti Mukherjee
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Manisha Poudyal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Kritika Dave
- Sunita Sanghi Centre of Aging and Neurodegenerative Diseases, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Pradeep Kadu
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Samir K Maji
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
- Sunita Sanghi Centre of Aging and Neurodegenerative Diseases, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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2
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Zhao T, Duan S, Li J, Zheng H, Liu C, Zhang H, Luo H, Xu Y. Mapping of repeat-associated non-AUG (RAN) translation knowledge: A bibliometric analysis. Heliyon 2024; 10:e29141. [PMID: 38628764 PMCID: PMC11019168 DOI: 10.1016/j.heliyon.2024.e29141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/08/2024] [Accepted: 04/01/2024] [Indexed: 04/19/2024] Open
Abstract
Over 50 genetic human disorders are attributed to the irregular expansion of microsatellites. These expanded microsatellite sequences can experience bidirectional transcription, leading to new reading frames. Beyond the standard AUG initiation or adjacent start codons, they are translated into proteins characterized by disease-causing amino acid repeats through repeat-associated non-AUG translation. Despite its significance, there's a discernible gap in comprehensive and objective articles on RAN translation. This study endeavors to evaluate and delineate the contemporary landscape and progress of RAN translation research via a bibliometric analysis. We sourced literature on RAN translation from the Web of Science Core Collection. Utilizing two bibliometric analysis tools, CiteSpace and VOSviewer, we gauged individual impacts and interactions by examining annual publications, journals, co-cited journals, countries/regions, institutions, authors, and co-cited authors. Following this, we assessed the co-occurrence and bursts of keywords and co-cited references to pinpoint research hotspots and trending in RAN translation. Between 2011 and 2022, 1317 authors across 359 institutions from 34 countries/regions contributed to 250 publications on RAN translation, spread across 118 academic journals. This article presents a systematic, objective, and comprehensive analysis of the current literature on RAN translation. Our findings emphasize that mechanisms related to C9orf72 ALS/FTD are pivotal topics in the realm of RAN translation, with cellular stress and the utilization of small molecule marking the trending research areas.
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Affiliation(s)
- Taiqi Zhao
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Suying Duan
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Jiaqi Li
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Honglin Zheng
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- The Academy of Medical Sciences of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Chenyang Liu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Hang Zhang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Haiyang Luo
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Institute of Neuroscience, Zhengzhou University, Zhengzhou, Henan, China
| | - Yuming Xu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
- Institute of Neuroscience, Zhengzhou University, Zhengzhou, Henan, China
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3
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Chaisson MJP, Sulovari A, Valdmanis PN, Miller DE, Eichler EE. Advances in the discovery and analyses of human tandem repeats. Emerg Top Life Sci 2023; 7:361-381. [PMID: 37905568 PMCID: PMC10806765 DOI: 10.1042/etls20230074] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 10/18/2023] [Accepted: 10/18/2023] [Indexed: 11/02/2023]
Abstract
Long-read sequencing platforms provide unparalleled access to the structure and composition of all classes of tandemly repeated DNA from STRs to satellite arrays. This review summarizes our current understanding of their organization within the human genome, their importance with respect to disease, as well as the advances and challenges in understanding their genetic diversity and functional effects. Novel computational methods are being developed to visualize and associate these complex patterns of human variation with disease, expression, and epigenetic differences. We predict accurate characterization of this repeat-rich form of human variation will become increasingly relevant to both basic and clinical human genetics.
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Affiliation(s)
- Mark J P Chaisson
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, U.S.A
- The Genomic and Epigenomic Regulation Program, USC Norris Cancer Center, University of Southern California, Los Angeles, CA 90089, U.S.A
| | - Arvis Sulovari
- Computational Biology, Cajal Neuroscience Inc, Seattle, WA 98102, U.S.A
| | - Paul N Valdmanis
- Division of Medical Genetics, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, U.S.A
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, U.S.A
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, U.S.A
| | - Danny E Miller
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, U.S.A
- Brotman Baty Institute for Precision Medicine, University of Washington, Seattle, WA 98195, U.S.A
- Department of Pediatrics, University of Washington, Seattle, WA 98195, U.S.A
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, U.S.A
- Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, U.S.A
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Haga CL, Phinney DG. Strategies for targeting RNA with small molecule drugs. Expert Opin Drug Discov 2023; 18:135-147. [PMID: 35934990 DOI: 10.1080/17460441.2022.2111414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Historically, therapeutic treatment of disease has been restricted to targeting proteins. Of the approximately 20,000 translated human proteins, approximately 1600 are associated with diseases. Strikingly, less than 15% of disease-associated proteins are predicted or known to be 'druggable.' While the concept and narrative of protein druggability continue to evolve with the development of novel technological and pharmacological advances, most of the human proteome remains undrugged. Recent genomic studies indicate that less than 2% of the human genome encodes for proteins, and while as much as 75% of the genome is transcribed, RNA has largely been ignored as a druggable target for therapeutic interventions. AREAS COVERED This review delineates the theory and techniques involved in the development of small molecule inhibitors of RNAs from brute force, high-throughput screening technologies to de novo molecular design using computational machine and deep learning. We will also highlight the potential pitfalls and limitations of targeting RNA with small molecules. EXPERT OPINION Although significant advances have recently been made in developing systems to identify small molecule inhibitors of RNAs, many challenges remain. Focusing on RNA structure and ligand binding sites may help bring drugging RNA in line with traditional protein drug targeting.
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Affiliation(s)
- Christopher L Haga
- Department of Molecular Medicine, UF Scripps Biomedical Research, Jupiter, FL, USA
| | - Donald G Phinney
- Department of Molecular Medicine, UF Scripps Biomedical Research, Jupiter, FL, USA
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Nabariya DK, Heinz A, Derksen S, Krauß S. Intracellular and intercellular transport of RNA organelles in CXG repeat disorders: The strength of weak ties. Front Mol Biosci 2022; 9:1000932. [PMID: 36589236 PMCID: PMC9800848 DOI: 10.3389/fmolb.2022.1000932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 12/06/2022] [Indexed: 12/23/2022] Open
Abstract
RNA is a vital biomolecule, the function of which is tightly spatiotemporally regulated. RNA organelles are biological structures that either membrane-less or surrounded by membrane. They are produced by the all the cells and indulge in vital cellular mechanisms. They include the intracellular RNA granules and the extracellular exosomes. RNA granules play an essential role in intracellular regulation of RNA localization, stability and translation. Aberrant regulation of RNA is connected to disease development. For example, in microsatellite diseases such as CXG repeat expansion disorders, the mutant CXG repeat RNA's localization and function are affected. RNA is not only transported intracellularly but can also be transported between cells via exosomes. The loading of the exosomes is regulated by RNA-protein complexes, and recent studies show that cytosolic RNA granules and exosomes share common content. Intracellular RNA granules and exosome loading may therefore be related. Exosomes can also transfer pathogenic molecules of CXG diseases from cell to cell, thereby driving disease progression. Both intracellular RNA granules and extracellular RNA vesicles may serve as a source for diagnostic and treatment strategies. In therapeutic approaches, pharmaceutical agents may be loaded into exosomes which then transport them to the desired cells/tissues. This is a promising target specific treatment strategy with few side effects. With respect to diagnostics, disease-specific content of exosomes, e.g., RNA-signatures, can serve as attractive biomarker of central nervous system diseases detecting early physiological disturbances, even before symptoms of neurodegeneration appear and irreparable damage to the nervous system occurs. In this review, we summarize the known function of cytoplasmic RNA granules and extracellular vesicles, as well as their role and dysfunction in CXG repeat expansion disorders. We also provide a summary of established protocols for the isolation and characterization of both cytoplasmic and extracellular RNA organelles.
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Affiliation(s)
| | | | | | - Sybille Krauß
- Human Biology/Neurobiology, Institute of Biology, Faculty IV, School of Science and Technology, University of Siegen, Siegen, Germany
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Ly S, Didiot MC, Ferguson CM, Coles AH, Miller R, Chase K, Echeverria D, Wang F, Sadri-Vakili G, Aronin N, Khvorova A. Mutant huntingtin messenger RNA forms neuronal nuclear clusters in rodent and human brains. Brain Commun 2022; 4:fcac248. [PMID: 36458209 PMCID: PMC9707646 DOI: 10.1093/braincomms/fcac248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 07/14/2022] [Accepted: 10/12/2022] [Indexed: 01/25/2023] Open
Abstract
Mutant messenger RNA (mRNA) and protein contribute to the clinical manifestation of many repeat-associated neurological disorders, with the presence of nuclear RNA clusters being a common pathological feature. Yet, investigations into Huntington's disease-caused by a CAG repeat expansion in exon 1 of the huntingtin (HTT) gene-have primarily focused on toxic protein gain-of-function as the primary disease-causing feature. To date, mutant HTT mRNA has not been identified as an in vivo hallmark of Huntington's disease. Here, we report that, in two Huntington's disease mouse models (YAC128 and BACHD-97Q-ΔN17), mutant HTT mRNA is retained in the nucleus. Widespread formation of large mRNA clusters (∼0.6-5 µm3) occurred in 50-75% of striatal and cortical neurons. Cluster formation was independent of age and driven by expanded repeats. Clusters associate with chromosomal transcriptional sites and quantitatively co-localize with the aberrantly processed N-terminal exon 1-intron 1 mRNA isoform, HTT1a. HTT1a mRNA clusters are observed in a subset of neurons from human Huntington's disease post-mortem brain and are likely caused by somatic expansion of repeats. In YAC128 mice, clusters, but not individual HTT mRNA, are resistant to antisense oligonucleotide treatment. Our findings identify mutant HTT/HTT1a mRNA clustering as an early, robust molecular signature of Huntington's disease, providing in vivo evidence that Huntington's disease is a repeat expansion disease with mRNA involvement.
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Affiliation(s)
| | | | | | - Andrew H Coles
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Rachael Miller
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Kathryn Chase
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Dimas Echeverria
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Feng Wang
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Ghazaleh Sadri-Vakili
- Mass General Institute for Neurodegenerative Disease, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Neil Aronin
- Correspondence may also be addressed to: Neil Aronin 368 Plantation Street, Albert Sherman Center Worcester, MA 01655, USA. E-mail:
| | - Anastasia Khvorova
- Correspondence to: Anastasia Khvorova 368 Plantation Street, Albert Sherman Center Worcester, MA 01655, USA E-mail:
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7
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Yousuf A, Ahmed N, Qurashi A. Non-canonical DNA/RNA structures associated with the pathogenesis of Fragile X-associated tremor/ataxia syndrome and Fragile X syndrome. Front Genet 2022; 13:866021. [PMID: 36110216 PMCID: PMC9468596 DOI: 10.3389/fgene.2022.866021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 07/22/2022] [Indexed: 11/13/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) and fragile X syndrome (FXS) are primary examples of fragile X-related disorders (FXDs) caused by abnormal expansion of CGG repeats above a certain threshold in the 5′-untranslated region of the fragile X mental retardation (FMR1) gene. Both diseases have distinct clinical manifestations and molecular pathogenesis. FXTAS is a late-adult-onset neurodegenerative disorder caused by a premutation (PM) allele (CGG expansion of 55–200 repeats), resulting in FMR1 gene hyperexpression. On the other hand, FXS is a neurodevelopmental disorder that results from a full mutation (FM) allele (CGG expansions of ≥200 repeats) leading to heterochromatization and transcriptional silencing of the FMR1 gene. The main challenge is to determine how CGG repeat expansion affects the fundamentally distinct nature of FMR1 expression in FM and PM ranges. Abnormal CGG repeat expansions form a variety of non-canonical DNA and RNA structures that can disrupt various cellular processes and cause distinct effects in PM and FM alleles. Here, we review these structures and how they are related to underlying mutations and disease pathology in FXS and FXTAS. Finally, as new CGG expansions within the genome have been identified, it will be interesting to determine their implications in disease pathology and treatment.
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8
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Almehmadi LM, Valsangkar VA, Halvorsen K, Zhang Q, Sheng J, Lednev IK. Surface-enhanced Raman spectroscopy for drug discovery: peptide-RNA binding. Anal Bioanal Chem 2022; 414:6009-6016. [PMID: 35764806 PMCID: PMC9404289 DOI: 10.1007/s00216-022-04190-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 06/06/2022] [Accepted: 06/21/2022] [Indexed: 11/01/2022]
Abstract
The ever-growing demand for new drugs highlights the need to develop novel cost- and time-effective techniques for drug discovery. Surface-enhanced Raman spectroscopy (SERS) is an emerging ultrasensitive and label-free technique that allows for the efficient detection and characterization of molecular interactions. We have recently developed a SERS platform for detecting a single protein molecule linked to a gold substrate (Almehmadi et al. Scientific Reports 2019). In this study, we extended the approach to probe the binding of potential drugs to RNA targets. To demonstrate the proof of concept, two 16-amino acid residue peptides with close primary structures and different binding affinities to the RNA CUG repeat related to myotonic dystrophy were tested. Three-microliter solutions of the RNA repeat with these peptides at nanomolar concentrations were probed using the developed approach, and the binding of only one peptide was demonstrated. The SER spectra exhibited significant fluctuations along with a sudden strong enhancement as spectra were collected consecutively from individual spots. Principal component analysis (PCA) of the SER spectral datasets indicated that free RNA repeats could be differentiated from those complexed with a peptide with 100% accuracy. The developed SERS platform provides a novel opportunity for label-free screening of RNA-binding peptides for drug discovery. Schematic representation of the SERS platform for drug discovery developed in this study.
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Affiliation(s)
- Lamyaa M Almehmadi
- Department of Chemistry, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA.,College of Arts and Science, RNA Institute, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Vibhav A Valsangkar
- Department of Chemistry, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA.,College of Arts and Science, RNA Institute, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Ken Halvorsen
- College of Arts and Science, RNA Institute, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Qiang Zhang
- Department of Chemistry, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Jia Sheng
- Department of Chemistry, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA. .,College of Arts and Science, RNA Institute, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA.
| | - Igor K Lednev
- Department of Chemistry, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA. .,College of Arts and Science, RNA Institute, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA.
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9
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Mishra R, Bansal A, Mishra A. LISTERIN E3 Ubiquitin Ligase and Ribosome-Associated Quality Control (RQC) Mechanism. Mol Neurobiol 2021; 58:6593-6609. [PMID: 34590243 DOI: 10.1007/s12035-021-02564-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 09/12/2021] [Indexed: 01/09/2023]
Abstract
According to cellular demands, ribosomes synthesize and maintain the desired pool of proteins inside the cell. However, sometimes due to defects in ribosomal machinery and faulty mRNAs, these nascent polypeptides are constantly under threat to become non-functional. In such conditions, cells acquire the help of ribosome-associated quality control mechanisms (RQC) to eliminate such aberrant nascent proteins. The primary regulator of RQC is RING domain containing LISTERIN E3 ubiquitin ligase, which is associated with ribosomes and alleviates non-stop proteins-associated stress in cells. Mouse RING finger protein E3 ubiquitin ligase LISTERIN is crucial for embryonic development, and a loss in its function causes neurodegeneration. LISTERIN is overexpressed in the mouse brain and spinal cord regions, and its perturbed functions generate neurological and motor deficits, but the mechanism of the same is unclear. Overall, LISTERIN is crucial for brain health and brain development. The present article systematically describes the detailed nature, molecular functions, and cellular physiological characterization of LISTERIN E3 ubiquitin ligase. Improve comprehension of LISTERIN's neurological roles may uncover pathways linked with neurodegeneration, which in turn might elucidate a promising novel therapeutic intervention against human neurodegenerative diseases.
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Affiliation(s)
- Ribhav Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Karwar, Rajasthan, 342037, India
| | - Anurag Bansal
- Center for Converging Technologies, Jaipur, University of Rajasthan, Jaipur, 302001, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Karwar, Rajasthan, 342037, India.
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Sabater-Arcis M, Bargiela A, Moreno N, Poyatos-Garcia J, Vilchez JJ, Artero R. Musashi-2 contributes to myotonic dystrophy muscle dysfunction by promoting excessive autophagy through miR-7 biogenesis repression. MOLECULAR THERAPY. NUCLEIC ACIDS 2021; 25:652-667. [PMID: 34589284 PMCID: PMC8463325 DOI: 10.1016/j.omtn.2021.08.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 08/10/2021] [Indexed: 02/07/2023]
Abstract
Skeletal muscle symptoms strongly contribute to mortality of myotonic dystrophy type 1 (DM1) patients. DM1 is a neuromuscular genetic disease caused by CTG repeat expansions that, upon transcription, sequester the Muscleblind-like family of proteins and dysregulate alternative splicing of hundreds of genes. However, mis-splicing does not satisfactorily explain muscle atrophy and wasting, and several other contributing factors have been suggested, including hyperactivated autophagy leading to excessive catabolism. MicroRNA (miR)-7 has been demonstrated to be necessary and sufficient to repress the autophagy pathway in cell models of the disease, but the origin of its low levels in DM1 was unknown. We have found that the RNA-binding protein Musashi-2 (MSI2) is upregulated in patient-derived myoblasts and biopsy samples. Because it has been previously reported that MSI2 controls miR-7 biogenesis, we tested the hypothesis that excessive MSI2 was repressing miR-7 maturation. Using gene-silencing strategies (small interfering RNAs [siRNAs] and gapmers) and the small molecule MSI2-inhibitor Ro 08-2750, we demonstrate that reducing MSI2 levels or activity boosts miR-7 expression, represses excessive autophagy, and downregulates atrophy-related genes of the UPS system. We also detect a significant upregulation of MBNL1 upon MSI2 silencing. Taken together, we propose MSI2 as a new therapeutic target to treat muscle dysfunction in DM1.
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Affiliation(s)
- Maria Sabater-Arcis
- Translational Genomics Group, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, 46100 Burjasot, Valencia, Spain
- INCLIVA Biomedical Research Institute, 46100 Burjasot, Valencia, Spain
| | - Ariadna Bargiela
- Translational Genomics Group, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, 46100 Burjasot, Valencia, Spain
- INCLIVA Biomedical Research Institute, 46100 Burjasot, Valencia, Spain
- Corresponding author: Ariadna Bargiela, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Dr. Moliner, 50, 46100 Burjasot, Valencia, Spain.
| | - Nerea Moreno
- Translational Genomics Group, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, 46100 Burjasot, Valencia, Spain
- INCLIVA Biomedical Research Institute, 46100 Burjasot, Valencia, Spain
| | - Javier Poyatos-Garcia
- Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER), Valencia, Spain
- Neuromuscular Research Unit, Neurology Department, Instituto de Investigación Sanitaria la Fe, Hospital Universitari i Politécnic La Fe, 46026 Valencia, Spain
| | - Juan J. Vilchez
- Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER), Valencia, Spain
- Neuromuscular Research Unit, Neurology Department, Instituto de Investigación Sanitaria la Fe, Hospital Universitari i Politécnic La Fe, 46026 Valencia, Spain
| | - Ruben Artero
- Translational Genomics Group, University Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, 46100 Burjasot, Valencia, Spain
- INCLIVA Biomedical Research Institute, 46100 Burjasot, Valencia, Spain
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Bhatti GK, Khullar N, Sidhu IS, Navik US, Reddy AP, Reddy PH, Bhatti JS. Emerging role of non-coding RNA in health and disease. Metab Brain Dis 2021; 36:1119-1134. [PMID: 33881724 PMCID: PMC8058498 DOI: 10.1007/s11011-021-00739-y] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 04/14/2021] [Indexed: 12/12/2022]
Abstract
Human diseases have always been a significant turf of concern since the origin of mankind. It is cardinal to know the cause, treatment, and cure for every disease condition. With the advent and advancement in technology, the molecular arena at the microscopic level to study the mechanism, progression, and therapy is more rational and authentic pave than a macroscopic approach. Non-coding RNAs (ncRNAs) have now emerged as indispensable players in the diagnosis, development, and therapeutics of every abnormality concerning physiology, pathology, genetics, epigenetics, oncology, and developmental diseases. This is a comprehensive attempt to collate all the existing and proven strategies, techniques, mechanisms of genetic disorders including Silver Russell Syndrome, Fascio- scapula humeral muscular dystrophy, cardiovascular diseases (atherosclerosis, cardiac fibrosis, hypertension, etc.), neurodegenerative diseases (Spino-cerebral ataxia type 7, Spino-cerebral ataxia type 8, Spinal muscular atrophy, Opitz-Kaveggia syndrome, etc.) cancers (cervix, breast, lung cancer, etc.), and infectious diseases (viral) studied so far. This article encompasses discovery, biogenesis, classification, and evolutionary prospects of the existence of this junk RNA along with the integrated networks involving chromatin remodelling, dosage compensation, genome imprinting, splicing regulation, post-translational regulation and proteomics. In conclusion, all the major human diseases are discussed with a facilitated technology transfer, advancements, loopholes, and tentative future research prospects have also been proposed.
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Affiliation(s)
- Gurjit Kaur Bhatti
- Department of Medical Lab Technology, University Institute of Applied Health Sciences, Chandigarh University, Mohali, Punjab India
| | - Naina Khullar
- Department of Zoology, Mata Gujri College, Fatehgarh Sahib, Punjab India
| | | | - Uma Shanker Navik
- Department of Pharmacology, Central University of Punjab, Bathinda, India
| | | | - P. Hemachandra Reddy
- Neuroscience & Pharmacology, Texas Tech University Health Sciences Center, Lubbock, TX USA
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX USA
- Departments of Neurology, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX USA
- Public Health Department of Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX USA
- Department of Speech, Language and Hearing Sciences, School Health Professions, Texas Tech University Health Sciences Center, Lubbock, TX USA
- Cell Biology & Biochemistry, Neuroscience & Pharmacology, Neurology, Public Health, School of Health Professions, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX 79430 USA
| | - Jasvinder Singh Bhatti
- Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda, India
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12
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Świtońska-Kurkowska K, Krist B, Delimata J, Figiel M. Juvenile Huntington's Disease and Other PolyQ Diseases, Update on Neurodevelopmental Character and Comparative Bioinformatic Review of Transcriptomic and Proteomic Data. Front Cell Dev Biol 2021; 9:642773. [PMID: 34277598 PMCID: PMC8281051 DOI: 10.3389/fcell.2021.642773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 06/10/2021] [Indexed: 01/18/2023] Open
Abstract
Polyglutamine (PolyQ) diseases are neurodegenerative disorders caused by the CAG repeat expansion mutation in affected genes resulting in toxic proteins containing a long chain of glutamines. There are nine PolyQ diseases: Huntington’s disease (HD), spinocerebellar ataxias (types 1, 2, 3, 6, 7, and 17), dentatorubral-pallidoluysian atrophy (DRPLA), and spinal bulbar muscular atrophy (SBMA). In general, longer CAG expansions and longer glutamine tracts lead to earlier disease presentations in PolyQ patients. Rarely, cases of extremely long expansions are identified for PolyQ diseases, and they consistently lead to juvenile or sometimes very severe infantile-onset polyQ syndromes. In apparent contrast to the very long CAG tracts, shorter CAGs and PolyQs in proteins seems to be the evolutionary factor enhancing human cognition. Therefore, polyQ tracts in proteins can be modifiers of brain development and disease drivers, which contribute neurodevelopmental phenotypes in juvenile- and adult-onset PolyQ diseases. Therefore we performed a bioinformatics review of published RNAseq polyQ expression data resulting from the presence of polyQ genes in search of neurodevelopmental expression patterns and comparison between diseases. The expression data were collected from cell types reflecting stages of development such as iPSC, neuronal stem cell, neurons, but also the adult patients and models for PolyQ disease. In addition, we extended our bioinformatic transcriptomic analysis by proteomics data. We identified a group of 13 commonly downregulated genes and proteins in HD mouse models. Our comparative bioinformatic review highlighted several (neuro)developmental pathways and genes identified within PolyQ diseases and mouse models responsible for neural growth, synaptogenesis, and synaptic plasticity.
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Affiliation(s)
| | - Bart Krist
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
| | - Joanna Delimata
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
| | - Maciej Figiel
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
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13
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Chintalaphani SR, Pineda SS, Deveson IW, Kumar KR. An update on the neurological short tandem repeat expansion disorders and the emergence of long-read sequencing diagnostics. Acta Neuropathol Commun 2021; 9:98. [PMID: 34034831 PMCID: PMC8145836 DOI: 10.1186/s40478-021-01201-x] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/17/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Short tandem repeat (STR) expansion disorders are an important cause of human neurological disease. They have an established role in more than 40 different phenotypes including the myotonic dystrophies, Fragile X syndrome, Huntington's disease, the hereditary cerebellar ataxias, amyotrophic lateral sclerosis and frontotemporal dementia. MAIN BODY STR expansions are difficult to detect and may explain unsolved diseases, as highlighted by recent findings including: the discovery of a biallelic intronic 'AAGGG' repeat in RFC1 as the cause of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS); and the finding of 'CGG' repeat expansions in NOTCH2NLC as the cause of neuronal intranuclear inclusion disease and a range of clinical phenotypes. However, established laboratory techniques for diagnosis of repeat expansions (repeat-primed PCR and Southern blot) are cumbersome, low-throughput and poorly suited to parallel analysis of multiple gene regions. While next generation sequencing (NGS) has been increasingly used, established short-read NGS platforms (e.g., Illumina) are unable to genotype large and/or complex repeat expansions. Long-read sequencing platforms recently developed by Oxford Nanopore Technology and Pacific Biosciences promise to overcome these limitations to deliver enhanced diagnosis of repeat expansion disorders in a rapid and cost-effective fashion. CONCLUSION We anticipate that long-read sequencing will rapidly transform the detection of short tandem repeat expansion disorders for both clinical diagnosis and gene discovery.
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Affiliation(s)
- Sanjog R. Chintalaphani
- School of Medicine, University of New South Wales, Sydney, 2052 Australia
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010 Australia
| | - Sandy S. Pineda
- Garvan-Weizmann Centre for Cellular Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010 Australia
- Brain and Mind Centre, University of Sydney, Camperdown, NSW 2050 Australia
| | - Ira W. Deveson
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010 Australia
- Faculty of Medicine, St Vincent’s Clinical School, University of New South Wales, Sydney, NSW 2010 Australia
| | - Kishore R. Kumar
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, NSW 2010 Australia
- Molecular Medicine Laboratory and Neurology Department, Central Clinical School, Concord Repatriation General Hospital, University of Sydney, Concord, NSW 2137 Australia
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14
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Xu K, Li Y, Allen EG, Jin P. Therapeutic Development for CGG Repeat Expansion-Associated Neurodegeneration. Front Cell Neurosci 2021; 15:655568. [PMID: 34054431 PMCID: PMC8149615 DOI: 10.3389/fncel.2021.655568] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 04/12/2021] [Indexed: 12/16/2022] Open
Abstract
Non-coding repeat expansions, such as CGG, GGC, CUG, CCUG, and GGGGCC, have been shown to be involved in many human diseases, particularly neurological disorders. Of the diverse pathogenic mechanisms proposed in these neurodegenerative diseases, dysregulated RNA metabolism has emerged as an important contributor. Expanded repeat RNAs that form particular structures aggregate to form RNA foci, sequestering various RNA binding proteins and consequently altering RNA splicing, transport, and other downstream biological processes. One of these repeat expansion-associated diseases, fragile X-associated tremor/ataxia syndrome (FXTAS), is caused by a CGG repeat expansion in the 5'UTR region of the fragile X mental retardation 1 (FMR1) gene. Moreover, recent studies have revealed abnormal GGC repeat expansion within the 5'UTR region of the NOTCH2NLC gene in both essential tremor (ET) and neuronal intranuclear inclusion disease (NIID). These CGG repeat expansion-associated diseases share genetic, pathological, and clinical features. Identification of the similarities at the molecular level could lead to a better understanding of the disease mechanisms as well as developing novel therapeutic strategies. Here, we highlight our current understanding of the molecular pathogenesis of CGG repeat expansion-associated diseases and discuss potential therapeutic interventions for these neurological disorders.
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Affiliation(s)
- Keqin Xu
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA, United States.,Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Yujing Li
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA, United States
| | - Emily G Allen
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA, United States
| | - Peng Jin
- Department of Human Genetics, School of Medicine, Emory University, Atlanta, GA, United States
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15
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Liu H, Lu YN, Paul T, Periz G, Banco MT, Ferré-D'Amaré AR, Rothstein JD, Hayes LR, Myong S, Wang J. A Helicase Unwinds Hexanucleotide Repeat RNA G-Quadruplexes and Facilitates Repeat-Associated Non-AUG Translation. J Am Chem Soc 2021; 143:7368-7379. [PMID: 33855846 DOI: 10.1021/jacs.1c00131] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The expansion of a hexanucleotide repeat GGGGCC (G4C2) in the C9orf72 gene is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The G4C2 expansion leads to repeat-associated non-AUG (RAN) translation and the production of toxic dipeptide repeat (DPR) proteins, but the mechanisms of RAN translation remain enigmatic. Here, we report that the RNA helicase DHX36 is a robust positive regulator of C9orf72 RAN translation. DHX36 has a high affinity for the G4C2 repeat RNA, preferentially binds to the repeat RNA's G-quadruplex conformation, and efficiently unwinds the G4C2 G-quadruplex structures. Native DHX36 interacts with the G4C2 repeat RNA and is essential for effective RAN translation in the cell. In induced pluripotent stem cells and differentiated motor neurons derived from C9orf72-linked ALS patients, reducing DHX36 significantly decreased the levels of endogenous DPR proteins. DHX36 is also aberrantly upregulated in tissues of C9orf72-linked ALS patients. These results indicate that DHX36 facilitates C9orf72 RAN translation by resolving repeat RNA G-quadruplex structures and may be a potential target for therapeutic intervention.
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Affiliation(s)
- Honghe Liu
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, United States.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Yu-Ning Lu
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, United States.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Tapas Paul
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Goran Periz
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, United States.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Michael T Banco
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, Maryland 20892, United States
| | - Adrian R Ferré-D'Amaré
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, Maryland 20892, United States
| | - Jeffrey D Rothstein
- Brain Science Institute and Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Lindsey R Hayes
- Brain Science Institute and Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Sua Myong
- Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jiou Wang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, United States.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, United States
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16
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Zhou Y, Sood R, Wang Q, Carrington B, Park M, Young AC, Birnbaum D, Liu Z, Ashizawa T, Mullikin JC, Koubeissi MZ, Liu P. Clinical and genomic analysis of a large Chinese family with familial cortical myoclonic tremor with epilepsy and SAMD12 intronic repeat expansion. Epilepsia Open 2021; 6:102-111. [PMID: 33681653 PMCID: PMC7918340 DOI: 10.1002/epi4.12450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 11/07/2020] [Accepted: 11/14/2020] [Indexed: 01/13/2023] Open
Abstract
Objective Our goal was to perform detailed clinical and genomic analysis of a large multigenerational Chinese family with 21 individuals showing symptoms of Familial Cortical Myoclonic Tremor with Epilepsy (FCMTE) that we have followed for over 20 years. Methods Patients were subjected to clinical evaluation, routine EEG, and structural magnetic resonance imaging. Whole exome sequencing, repeat-primed PCR, long-range PCR, and PacBio sequencing were performed to characterize the disease-causing mutation in this family. Results All evaluated patients manifested adult-onset seizures and presented with progressive myoclonic postural tremors starting after the third or fourth decade of life. Seizures typically diminished markedly in frequency with implementation of antiseizure medications but did not completely cease. The electroencephalogram of affected individuals showed generalized or multifocal spikes and slow wave complexes. An expansion of TTTTA motifs with addition of TTTCA motifs in intron 4 of SAMD12 was identified to segregate with the disease phenotype in this family. Furthermore, we found that the mutant allele is unstable and can undergo both contraction and expansion by changes in the number of repeat motifs each time it is passed to the next generation. The size of mutant allele varied from 5 to 5.5 kb with 549-603 copies of TTTTA and 287-343 copies of TTTCA repeat motifs in this family. Significance Our study provides a detailed description of clinical progression of FCMTE symptoms and its management with antiseizure medications. Our method of repeat analysis by PacBio sequencing of long-range PCR products does not require high-quality DNA and hence can be easily applied to other families to elucidate any correlation between the repeat size and phenotypic variables, such as, age of onset, and severity of symptoms.
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Affiliation(s)
- Yongxing Zhou
- Department of NeurologyMedStar St Mary’s Hospital/Georgetown University HospitalMedStar Medical GroupLeonardtownMDUSA
| | - Raman Sood
- Translational and Functional Genomics BranchNational Human Genome Research InstituteNational Institutes of HealthBethesdaMDUSA
| | - Qun Wang
- Epilepsy CenterDepartment of NeurologyBeijing Tiantan HospitalCapital Medical UniversityBeijingChina
- China National Clinical Research Center for Neurological DiseasesBeijingChina
| | - Blake Carrington
- Translational and Functional Genomics BranchNational Human Genome Research InstituteNational Institutes of HealthBethesdaMDUSA
| | - Morgan Park
- NIH Intramural Sequencing CenterNational Human Genome Research InstituteNational Institutes of HealthRockvilleMDUSA
| | - Alice C. Young
- NIH Intramural Sequencing CenterNational Human Genome Research InstituteNational Institutes of HealthRockvilleMDUSA
| | - Daniel Birnbaum
- Department of NeurologyEinstein Medical CenterPhiladelphiaPAUSA
| | - Zhao Liu
- Division of Pediatric NeurologyChildren's Hospital of IllinoisUniversity of Illinois College of MedicineChicagoILUSA
| | - Tetsuo Ashizawa
- Houston Methodist Neurological Institute and Research InstituteHoustonTXUSA
| | - James C. Mullikin
- NIH Intramural Sequencing CenterNational Human Genome Research InstituteNational Institutes of HealthRockvilleMDUSA
| | - Mohamad Z. Koubeissi
- Epilepsy CenterDepartment of NeurologyGeorge Washington UniversityWashingtonDCUSA
| | - Paul Liu
- Translational and Functional Genomics BranchNational Human Genome Research InstituteNational Institutes of HealthBethesdaMDUSA
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17
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Malnar M, Rogelj B. SFPQ regulates the accumulation of RNA foci and dipeptide repeat proteins from the expanded repeat mutation in C9orf72. J Cell Sci 2021; 134:jcs.256602. [PMID: 33495278 PMCID: PMC7904093 DOI: 10.1242/jcs.256602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 01/08/2021] [Indexed: 12/12/2022] Open
Abstract
The expanded GGGGCC repeat mutation in the C9orf72 gene is the most common genetic cause of the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The expansion is transcribed to sense and antisense RNA, which form RNA foci and bind cellular proteins. This mechanism of action is considered cytotoxic. Translation of the expanded RNA transcripts also leads to the accumulation of toxic dipeptide repeat proteins (DPRs). The RNA-binding protein splicing factor proline and glutamine rich (SFPQ), which is being increasingly associated with ALS and FTD pathology, binds to sense RNA foci. Here, we show that SFPQ plays an important role in the C9orf72 mutation. Overexpression of SFPQ resulted in higher numbers of both sense and antisense RNA foci and DPRs in transfected human embryonic kidney (HEK) cells. Conversely, reduced SPFQ levels resulted in lower numbers of RNA foci and DPRs in both transfected HEK cells and C9orf72 mutation-positive patient-derived fibroblasts and lymphoblasts. Therefore, we have revealed a role of SFPQ in regulating the C9orf72 mutation that has implications for understanding and developing novel therapeutic targets for ALS and FTD. This article has an associated First Person interview with the first author of the paper. Summary: Expression level modulation of the core paraspeckle protein SFPQ regulates sense and antisense RNA foci and dipeptide repeat protein accumulation in the C9orf72 mutation; SFPQ could be a therapeutic target in C9orf72 ALS and FTD.
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Affiliation(s)
- Mirjana Malnar
- Department of Biotechnology, Jožef Stefan Institute, 1000 Ljubljana, Slovenia.,Graduate School of Biomedicine, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Boris Rogelj
- Department of Biotechnology, Jožef Stefan Institute, 1000 Ljubljana, Slovenia .,Biomedical Research Institute, 1000 Ljubljana, Slovenia.,Faculty of Chemistry and Chemical Engineering, University of Ljubljana, 1000 Ljubljana, Slovenia
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18
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Mahadevan R, Bhoyar RC, Viswanathan N, Rajagopal RE, Essaki B, Suroliya V, Chelladurai R, Sankaralingam S, Shanmugam G, Vayanakkan S, Shamim U, Mathur A, Jain A, Imran M, Faruq M, Scaria V, Sivasubbu S, Kalyanaraman S. Genomic analysis of patients in a South Indian Community with autosomal dominant cortical tremor, myoclonus and epilepsy suggests a founder repeat expansion mutation in the SAMD12 gene. Brain Commun 2021; 3:fcaa214. [PMID: 33501421 PMCID: PMC7811760 DOI: 10.1093/braincomms/fcaa214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 10/15/2020] [Accepted: 10/25/2020] [Indexed: 12/11/2022] Open
Abstract
Autosomal Dominant Cortical Tremor, Myoclonus and Epilepsy is a non-progressive disorder characterized by distal tremors. Autosomal Dominant Cortical Tremor, Myoclonus and Epilepsy has been reported globally with different genetic predispositions of autosomal dominant inheritance with a high degree of penetrance. In south India, Autosomal Dominant Cortical Tremor, Myoclonus and Epilepsy has been reported in a large cohort of 48 families, in which the genetic defect was not identified. This report pertains to the whole-genome analysis of four individuals followed by repeat-primed PCR for 102 patients from a familial cohort of 325 individuals. All the patients underwent extensive clinical evaluation including neuropsychological examinations. The whole-genome sequencing was done for two affected and two unaffected individuals, belonging to two different families. The whole-genome sequencing analysis revealed the repeat expansion of TTTTA and TTTCA in intron 4 of the SAMD12 gene located on chromosome 8 in the patients affected with Autosomal Dominant Cortical Tremor, Myoclonus and Epilepsy, whereas the unaffected family members were negative for the similar expansion. Further, the repeat-primed PCR analysis of 102 patients showed the expansion of the TTTCA repeats in the intron 4 of SAMD12 gene. All patients registered for this study belong to a single community called “Nadar” whose nativity is confined to the southern districts of India, with reported unique genetic characteristics. This is the largest and most comprehensive single report on clinically and genetically characterized Autosomal Dominant Cortical Tremor, Myoclonus and Epilepsy patients belonging to a unique ethnic group worldwide.
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Affiliation(s)
- Radha Mahadevan
- Department of Neurology, Tirunelveli Medical College, Tirunelveli 627011, Tamil Nadu, India
| | - Rahul C Bhoyar
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | | | - Raskin Erusan Rajagopal
- Multidisciplinary Research Unit, Tirunelveli Medical College, Tirunelveli 627011, Tamil Nadu, India
| | - Bobby Essaki
- Department of Neurology, Tirunelveli Medical College, Tirunelveli 627011, Tamil Nadu, India
| | - Varun Suroliya
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Rachel Chelladurai
- Department of Neurology, Tirunelveli Medical College, Tirunelveli 627011, Tamil Nadu, India
| | | | | | | | - Uzma Shamim
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Aradhana Mathur
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Abhinav Jain
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Mohamed Imran
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Mohammed Faruq
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Vinod Scaria
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Sridhar Sivasubbu
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR-IGIB), Delhi 110025, India
| | - Shantaraman Kalyanaraman
- Multidisciplinary Research Unit, Tirunelveli Medical College, Tirunelveli 627011, Tamil Nadu, India
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19
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Shibata T, Nagano K, Ueyama M, Ninomiya K, Hirose T, Nagai Y, Ishikawa K, Kawai G, Nakatani K. Small molecule targeting r(UGGAA) n disrupts RNA foci and alleviates disease phenotype in Drosophila model. Nat Commun 2021; 12:236. [PMID: 33431896 PMCID: PMC7801683 DOI: 10.1038/s41467-020-20487-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/04/2020] [Indexed: 12/14/2022] Open
Abstract
Synthetic small molecules modulating RNA structure and function have therapeutic potential for RNA diseases. Here we report our discovery that naphthyridine carbamate dimer (NCD) targets disease-causing r(UGGAA)n repeat RNAs in spinocerebellar ataxia type 31 (SCA31). Structural analysis of the NCD-UGGAA/UGGAA complex by nuclear magnetic resonance (NMR) spectroscopy clarifies the mode of binding that recognizes four guanines in the UGGAA/UGGAA pentad by hydrogen bonding with four naphthyridine moieties of two NCD molecules. Biological studies show that NCD disrupts naturally occurring RNA foci built on r(UGGAA)n repeat RNA known as nuclear stress bodies (nSBs) by interfering with RNA–protein interactions resulting in the suppression of nSB-mediated splicing events. Feeding NCD to larvae of the Drosophila model of SCA31 alleviates the disease phenotype induced by toxic r(UGGAA)n repeat RNA. These studies demonstrate that small molecules targeting toxic repeat RNAs are a promising chemical tool for studies on repeat expansion diseases. Synthetic small molecules modulating RNA structure and function have therapeutic potential for RNA diseases. Here the authors show the mechanism by which a small molecule targets the disease-causing r(UGGAA)n repeat RNAs in spinocerebellar ataxia type 31.
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Affiliation(s)
- Tomonori Shibata
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research (ISIR), Osaka University, Ibaraki, Japan
| | - Konami Nagano
- Department of Life and Environmental Sciences, Faculty of Engineering, Chiba Institute of Technology, Chiba, Japan
| | - Morio Ueyama
- Department of Neurotherapeutics, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kensuke Ninomiya
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Tetsuro Hirose
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
| | - Yoshitaka Nagai
- Department of Neurotherapeutics, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kinya Ishikawa
- Center for Personalized Medicine for Healthy Aging, Tokyo Medical and Dental University, Tokyo, Japan
| | - Gota Kawai
- Department of Life and Environmental Sciences, Faculty of Engineering, Chiba Institute of Technology, Chiba, Japan
| | - Kazuhiko Nakatani
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research (ISIR), Osaka University, Ibaraki, Japan.
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20
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21
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Donaldson J, Powell S, Rickards N, Holmans P, Jones L. What is the Pathogenic CAG Expansion Length in Huntington's Disease? J Huntingtons Dis 2021; 10:175-202. [PMID: 33579866 PMCID: PMC7990448 DOI: 10.3233/jhd-200445] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Huntington's disease (HD) (OMIM 143100) is caused by an expanded CAG repeat tract in the HTT gene. The inherited CAG length is known to expand further in somatic and germline cells in HD subjects. Age at onset of the disease is inversely correlated with the inherited CAG length, but is further modulated by a series of genetic modifiers which are most likely to act on the CAG repeat in HTT that permit it to further expand. Longer repeats are more prone to expansions, and this expansion is age dependent and tissue-specific. Given that the inherited tract expands through life and most subjects develop disease in mid-life, this implies that in cells that degenerate, the CAG length is likely to be longer than the inherited length. These findings suggest two thresholds- the inherited CAG length which permits further expansion, and the intracellular pathogenic threshold, above which cells become dysfunctional and die. This two-step mechanism has been previously proposed and modelled mathematically to give an intracellular pathogenic threshold at a tract length of 115 CAG (95% confidence intervals 70- 165 CAG). Empirically, the intracellular pathogenic threshold is difficult to determine. Clues from studies of people and models of HD, and from other diseases caused by expanded repeat tracts, place this threshold between 60- 100 CAG, most likely towards the upper part of that range. We assess this evidence and discuss how the intracellular pathogenic threshold in manifest disease might be better determined. Knowing the cellular pathogenic threshold would be informative for both understanding the mechanism in HD and deploying treatments.
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Affiliation(s)
- Jasmine Donaldson
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK
| | - Sophie Powell
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK
| | - Nadia Rickards
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK
| | - Peter Holmans
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK
| | - Lesley Jones
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK
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22
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Advani VM, Ivanov P. Stress granule subtypes: an emerging link to neurodegeneration. Cell Mol Life Sci 2020; 77:4827-4845. [PMID: 32500266 PMCID: PMC7668291 DOI: 10.1007/s00018-020-03565-0] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 05/17/2020] [Accepted: 05/26/2020] [Indexed: 12/13/2022]
Abstract
Stress Granules (SGs) are membraneless cytoplasmic RNA granules, which contain translationally stalled mRNAs, associated translation initiation factors and multiple RNA-binding proteins (RBPs). They are formed in response to various stresses and contribute to reprogramming of cellular metabolism to aid cell survival. Because of their cytoprotective nature, association with translation regulation and cell signaling, SGs are an essential component of the integrated stress response pathway, a complex adaptive program central to stress management. Recent advances in SG biology unambiguously demonstrate that SGs are heterogeneous in their RNA and protein content leading to the idea that various SG subtypes exist. These SG variants are formed in cell type- and stress-specific manners and differ in their composition, dynamics of assembly and disassembly, and contribution to cell viability. As aberrant SG dynamics contribute to the formation of pathological persistent SGs that are implicated in neurodegenerative diseases, the biology of different SG subtypes may be directly implicated in neurodegeneration. Here, we will discuss mechanisms of SG formation, their subtypes, and potential contribution to health and disease.
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Affiliation(s)
- Vivek M Advani
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA.
- Department of Medicine, Harvard Medical School, Boston, MA, USA.
| | - Pavel Ivanov
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital, Boston, MA, USA.
- Department of Medicine, Harvard Medical School, Boston, MA, USA.
- Harvard Initiative for RNA Medicine, Boston, MA, USA.
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23
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Schwartz JL, Jones KL, Yeo GW. Repeat RNA expansion disorders of the nervous system: post-transcriptional mechanisms and therapeutic strategies. Crit Rev Biochem Mol Biol 2020; 56:31-53. [PMID: 33172304 PMCID: PMC8192115 DOI: 10.1080/10409238.2020.1841726] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Dozens of incurable neurological disorders result from expansion of short repeat sequences in both coding and non-coding regions of the transcriptome. Short repeat expansions underlie microsatellite repeat expansion (MRE) disorders including myotonic dystrophy (DM1, CUG50–3,500 in DMPK; DM2, CCTG75–11,000 in ZNF9), fragile X tremor ataxia syndrome (FXTAS, CGG50–200 in FMR1), spinal bulbar muscular atrophy (SBMA, CAG40–55 in AR), Huntington’s disease (HD, CAG36–121 in HTT), C9ORF72-amyotrophic lateral sclerosis (ALS)/frontotemporal dementia (FTD and C9-ALS/FTD, GGGGCC in C9ORF72), and many others, like ataxias. Recent research has highlighted several mechanisms that may contribute to pathology in this heterogeneous class of neurological MRE disorders – bidirectional transcription, intranuclear RNA foci, and repeat associated non-AUG (RAN) translation – which are the subject of this review. Additionally, many MRE disorders share similar underlying molecular pathologies that have been recently targeted in experimental and preclinical contexts. We discuss the therapeutic potential of versatile therapeutic strategies that may selectively target disrupted RNA-based processes and may be readily adaptable for the treatment of multiple MRE disorders. Collectively, the strategies under consideration for treatment of multiple MRE disorders include reducing levels of toxic RNA, preventing RNA foci formation, and eliminating the downstream cellular toxicity associated with peptide repeats produced by RAN translation. While treatments are still lacking for the majority of MRE disorders, several promising therapeutic strategies have emerged and will be evaluated within this review.
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Affiliation(s)
- Joshua L Schwartz
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Krysten Leigh Jones
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
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24
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Skariah G, Todd PK. Translational control in aging and neurodegeneration. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1628. [PMID: 32954679 DOI: 10.1002/wrna.1628] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/19/2020] [Accepted: 09/07/2020] [Indexed: 12/13/2022]
Abstract
Protein metabolism plays central roles in age-related decline and neurodegeneration. While a large body of research has explored age-related changes in protein degradation, alterations in the efficiency and fidelity of protein synthesis with aging are less well understood. Age-associated changes occur in both the protein synthetic machinery (ribosomal proteins and rRNA) and within regulatory factors controlling translation. At the same time, many of the interventions that prolong lifespan do so in part by pre-emptively decreasing protein synthesis rates to allow better harmonization to age-related declines in protein catabolism. Here we review the roles of translation regulation in aging, with a specific focus on factors implicated in age-related neurodegeneration. We discuss how emerging technologies such as ribosome profiling and superior mass spectrometric approaches are illuminating age-dependent mRNA-specific changes in translation rates across tissues to reveal a critical interplay between catabolic and anabolic pathways that likely contribute to functional decline. These new findings point to nodes in posttranscriptional gene regulation that both contribute to aging and offer targets for therapy. This article is categorized under: Translation > Translation Regulation Translation > Ribosome Biogenesis Translation > Translation Mechanisms.
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Affiliation(s)
- Geena Skariah
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
- Ann Arbor VA Healthcare System, Department of Veterans Affairs, Ann Arbor, Michigan, USA
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25
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Course MM, Gudsnuk K, Smukowski SN, Winston K, Desai N, Ross JP, Sulovari A, Bourassa CV, Spiegelman D, Couthouis J, Yu CE, Tsuang DW, Jayadev S, Kay MA, Gitler AD, Dupre N, Eichler EE, Dion PA, Rouleau GA, Valdmanis PN. Evolution of a Human-Specific Tandem Repeat Associated with ALS. Am J Hum Genet 2020; 107:445-460. [PMID: 32750315 DOI: 10.1016/j.ajhg.2020.07.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/08/2020] [Indexed: 12/12/2022] Open
Abstract
Tandem repeats are proposed to contribute to human-specific traits, and more than 40 tandem repeat expansions are known to cause neurological disease. Here, we characterize a human-specific 69 bp variable number tandem repeat (VNTR) in the last intron of WDR7, which exhibits striking variability in both copy number and nucleotide composition, as revealed by long-read sequencing. In addition, greater repeat copy number is significantly enriched in three independent cohorts of individuals with sporadic amyotrophic lateral sclerosis (ALS). Each unit of the repeat forms a stem-loop structure with the potential to produce microRNAs, and the repeat RNA can aggregate when expressed in cells. We leveraged its remarkable sequence variability to align the repeat in 288 samples and uncover its mechanism of expansion. We found that the repeat expands in the 3'-5' direction, in groups of repeat units divisible by two. The expansion patterns we observed were consistent with duplication events, and a replication error called template switching. We also observed that the VNTR is expanded in both Denisovan and Neanderthal genomes but is fixed at one copy or fewer in non-human primates. Evaluating the repeat in 1000 Genomes Project samples reveals that some repeat segments are solely present or absent in certain geographic populations. The large size of the repeat unit in this VNTR, along with our multiplexed sequencing strategy, provides an unprecedented opportunity to study mechanisms of repeat expansion, and a framework for evaluating the roles of VNTRs in human evolution and disease.
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26
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Wan N, Chen Z, Wan L, Tang B, Jiang H. MR Imaging of SCA3/MJD. Front Neurosci 2020; 14:749. [PMID: 32848545 PMCID: PMC7417615 DOI: 10.3389/fnins.2020.00749] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/25/2020] [Indexed: 12/15/2022] Open
Abstract
Spinocerebellar ataxia type 3/Machado-Joseph disease (SCA3/MJD) is a progressive autosomal dominantly inherited cerebellar ataxia characterized by the aggregation of polyglutamine-expanded protein within neuronal nuclei in the brain, which can lead to brain damage that precedes the onset of clinical manifestations. Magnetic resonance imaging (MRI) techniques such as morphometric MRI, diffusion tensor imaging (DTI), functional magnetic resonance imaging (fMRI), and magnetic resonance spectroscopy (MRS) have gained increasing attention as non-invasive and quantitative methods for the assessment of structural and functional alterations in clinical SCA3/MJD patients as well as preclinical carriers. Morphometric MRI has demonstrated typical patterns of atrophy or volume loss in the cerebellum and brainstem with extensive lesions in some supratentorial areas. DTI has detected widespread microstructural alterations in brain white matter, which indicate disrupted brain anatomical connectivity. Task-related fMRI has presented unusual brain activation patterns within the cerebellum and some extracerebellar tissue, reflecting the decreased functional connectivity of these brain regions in SCA3/MJD subjects. MRS has revealed abnormal neurochemical profiles, such as the levels or ratios of N-acetyl aspartate, choline, and creatine, in both clinical cases and preclinical cases before the alterations in brain anatomical structure. Moreover, a number of studies have reported correlations of MR imaging alterations with clinical and genetic features. The utility of these MR imaging techniques can help to identify preclinical SCA3/MJD carriers, monitor disease progression, evaluate response to therapeutic interventions, and illustrate the pathophysiological mechanisms underlying the occurrence, development, and prognosis of SCA3/MJD.
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Affiliation(s)
- Na Wan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Zhao Chen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
| | - Linlin Wan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
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27
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He F, Flores BN, Krans A, Frazer M, Natla S, Niraula S, Adefioye O, Barmada SJ, Todd PK. The carboxyl termini of RAN translated GGGGCC nucleotide repeat expansions modulate toxicity in models of ALS/FTD. Acta Neuropathol Commun 2020; 8:122. [PMID: 32753055 PMCID: PMC7401224 DOI: 10.1186/s40478-020-01002-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 07/22/2020] [Indexed: 12/13/2022] Open
Abstract
An intronic hexanucleotide repeat expansion in C9ORF72 causes familial and sporadic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). This repeat is thought to elicit toxicity through RNA mediated protein sequestration and repeat-associated non-AUG (RAN) translation of dipeptide repeat proteins (DPRs). We generated a series of transgenic Drosophila models expressing GGGGCC (G4C2) repeats either inside of an artificial intron within a GFP reporter or within the 5' untranslated region (UTR) of GFP placed in different downstream reading frames. Expression of 484 intronic repeats elicited minimal alterations in eye morphology, viability, longevity, or larval crawling but did trigger RNA foci formation, consistent with prior reports. In contrast, insertion of repeats into the 5' UTR elicited differential toxicity that was dependent on the reading frame of GFP relative to the repeat. Greater toxicity correlated with a short and unstructured carboxyl terminus (C-terminus) in the glycine-arginine (GR) RAN protein reading frame. This change in C-terminal sequence triggered nuclear accumulation of all three RAN DPRs. A similar differential toxicity and dependence on the GR C-terminus was observed when repeats were expressed in rodent neurons. The presence of the native C-termini across all three reading frames was partly protective. Taken together, these findings suggest that C-terminal sequences outside of the repeat region may alter the behavior and toxicity of dipeptide repeat proteins derived from GGGGCC repeats.
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28
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Mystery of Expansion: DNA Metabolism and Unstable Repeats. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1241:101-124. [PMID: 32383118 DOI: 10.1007/978-3-030-41283-8_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The mammalian genome mostly contains repeated sequences. Some of these repeats are in the regulatory elements of genes, and their instability, particularly the propensity to change the repeat unit number, is responsible for 36 well-known neurodegenerative human disorders. The mechanism of repeat expansion has been an unsolved question for more than 20 years. There are a few hypotheses describing models of mutation development. Every hypothesis is based on assumptions about unusual secondary structures that violate DNA metabolism processes in the cell. Some models are based on replication errors, and other models are based on mismatch repair or base excision repair errors. Additionally, it has been shown that epigenetic regulation of gene expression can influence the probability and frequency of expansion. In this review, we consider the molecular bases of repeat expansion disorders and discuss possible mechanisms of repeat expansion during cell metabolism.
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29
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Short Tandem Repeat-Enriched Architectural RNAs in Nuclear Bodies: Functions and Associated Diseases. Noncoding RNA 2020; 6:ncrna6010006. [PMID: 32093161 PMCID: PMC7151548 DOI: 10.3390/ncrna6010006] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 01/31/2020] [Accepted: 02/19/2020] [Indexed: 12/16/2022] Open
Abstract
Nuclear bodies are membraneless, phase-separated compartments that concentrate specific proteins and RNAs in the nucleus. They are believed to serve as sites for the modification, sequestration, and storage of specific factors, and to act as organizational hubs of chromatin structure to control gene expression and cellular function. Architectural (arc) RNA, a class of long noncoding RNA (lncRNA), plays essential roles in the formation of nuclear bodies. Herein, we focus on specific arcRNAs containing short tandem repeat-enriched sequences and introduce their biological functions and recently elucidated underlying molecular mechanism. In various neurodegenerative diseases, abnormal nuclear and cytoplasmic bodies are built on disease-causing RNAs or toxic RNAs with aberrantly expanded short tandem repeat-enriched sequences. We discuss the possible analogous functions of natural arcRNAs and toxic RNAs with short tandem repeat-enriched sequences. Finally, we describe the technical utility of short tandem repeat-enriched arcRNAs as a model for exploring the structures and functions of nuclear bodies, as well as the pathogenic mechanisms of neurodegenerative diseases.
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30
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Yu S, Li F, Huang X, Dong C, Ren J. In Situ Study of Interactions between Endogenous c-myc mRNA with CRDBP in a Single Living Cell by Combining Fluorescence Cross-Correlation Spectroscopy with Molecular Beacons. Anal Chem 2020; 92:2988-2996. [DOI: 10.1021/acs.analchem.9b03934] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Shengrong Yu
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Fucai Li
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Xiangyi Huang
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Chaoqing Dong
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Jicun Ren
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
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31
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Sawada J, Katayama T, Tokashiki T, Kikuchi S, Kano K, Takahashi K, Saito T, Adachi Y, Okamoto Y, Yoshimura A, Takashima H, Hasebe N. The First Case of Spinocerebellar Ataxia Type 8 in Monozygotic Twins. Intern Med 2020; 59:277-283. [PMID: 31554751 PMCID: PMC7008061 DOI: 10.2169/internalmedicine.2905-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Spinocerebellar ataxia type 8 (SCA8) is a rare hereditary cerebellar ataxia showing mainly pure cerebellar ataxia. We herein report cases of SCA8 in Japanese monozygotic twins that presented with nystagmus, dysarthria, and limb and truncal ataxia. Their ATXN8OS CTA/CTG repeats were 25/97. They showed similar manifestations, clinical courses, and cerebellar atrophy on magnetic resonance imaging. Some of their pedigrees had nystagmus but not ataxia. These are the first monozygotic twins with SCA8 to be reported anywhere in the world. Although not all subjects with the ATXN8OS CTG expansion develop cerebellar ataxia, these cases suggest the pathogenesis of ATXN8OS repeat expansions in hereditary cerebellar ataxia.
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Affiliation(s)
- Jun Sawada
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
| | - Takayuki Katayama
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
| | - Takashi Tokashiki
- Department of Neurology, National Hospital Organization Okinawa Hospital, Japan
| | - Shiori Kikuchi
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
| | - Kohei Kano
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
| | - Kae Takahashi
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
| | - Tsukasa Saito
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
| | - Yoshiki Adachi
- Department of Neurology, National Hospital Organization Matsue Medical Center, Japan
| | - Yuji Okamoto
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Japan
| | - Akiko Yoshimura
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Japan
| | - Naoyuki Hasebe
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
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32
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Mori S, Honda H, Ishii T, Yoshimura M, Sasagasako N, Suzuki SO, Taniwaki T, Iwaki T. Expanded polyglutamine impairs normal nuclear distribution of fused in sarcoma and poly (rC)‐binding protein 1 in Huntington's disease. Neuropathology 2019; 39:358-367. [DOI: 10.1111/neup.12600] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 07/25/2019] [Accepted: 08/08/2019] [Indexed: 12/14/2022]
Affiliation(s)
- Shinichiro Mori
- Department of NeuropathologyGraduate School of Medical Sciences, Kyushu University Fukuoka Japan
- Department of Neurology, Division of Respirology, Neurology and Rheumatology, Department of MedicineKurume University School of Medicine Kurume Japan
| | - Hiroyuki Honda
- Department of NeuropathologyGraduate School of Medical Sciences, Kyushu University Fukuoka Japan
| | - Takashi Ishii
- Department of BiochemistryFukuoka Dental College Fukuoka Japan
| | - Motoi Yoshimura
- Department of NeuropathologyGraduate School of Medical Sciences, Kyushu University Fukuoka Japan
| | - Naokazu Sasagasako
- Department of NeurologyNeuro‐Muscular Center, National Omuta Hospital Omuta Japan
| | - Satoshi O. Suzuki
- Department of NeuropathologyGraduate School of Medical Sciences, Kyushu University Fukuoka Japan
| | - Takayuki Taniwaki
- Department of Neurology, Division of Respirology, Neurology and Rheumatology, Department of MedicineKurume University School of Medicine Kurume Japan
| | - Toru Iwaki
- Department of NeuropathologyGraduate School of Medical Sciences, Kyushu University Fukuoka Japan
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33
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Peng H, Liang X, Long Z, Chen Z, Shi Y, Xia K, Meng L, Tang B, Qiu R, Jiang H. Gene-Related Cerebellar Neurodegeneration in SCA3/MJD: A Case-Controlled Imaging-Genetic Study. Front Neurol 2019; 10:1025. [PMID: 31616370 PMCID: PMC6768953 DOI: 10.3389/fneur.2019.01025] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 09/09/2019] [Indexed: 11/30/2022] Open
Abstract
Background: Spinocerebellar ataxia type 3/Machado-Joseph disease (SCA3/MJD) is one of the nine polyglutamine (polyQ) diseases and is caused by a CAG repeat expansion within the coding sequence of the ATXN3 gene. Few multimodal imaging analyses of the macro- and micro-structural changes have been performed. Methods: In the present study, we recruited 31 genetically-confirmed symptomatic SCA3/MJD patients and 31 healthy subjects as controls for a multimodal neuroimaging study using structural magnetic resonance imaging (sMRI), proton magnetic resonance spectroscopy (1H-MRS) and diffusion tensor imaging (DTI). Results: The SCA3/MJD patients displayed a significantly reduced of gray matter volume in the cerebellum, pons, midbrain and medulla, as well as inferior frontal gyrus and insula, and left superior frontal gyrus. The total International Cooperative Ataxia Rating Scale (ICARS) score was inversely correlated with the gray matter volume in the cerebellar culmen, pons and midbrain. The numbers of CAG repeats in the expanded alleles were inversely correlated with the gray matter in the cerebellar culmen. NAA/Cr and NAA/Cho ratio in the middle cerebellar peduncles, dentate nucleus, cerebellar vermis, and thalamus in the SCA3/MJD patients were significantly reduced when compared to that in the normal controls, suggesting neurochemical alterations in cerebellum in the SCA3/MJD patients. Tract-Based Spatial Statistics (TBSS) analysis revealed significant lower volume and mean FA values of the cerebellar peduncles, which inversely correlated with the total scores of ICARS in our patients. Conclusions: In this study, we demonstrated cerebellar degeneration in SCA3/MJD based on tissue volume, neurochemistry, and tissue microstructure. Moreover, the associations between the clinical measures, cerebellar degeneration and genetic variation support a distinct genotype-phenotype relationship in SCA3/MJD.
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Affiliation(s)
- Huirong Peng
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Xiaochun Liang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Zhe Long
- Department of Neurology, Second Xiangya Hospital, Central South University, Changsha, China
| | - Zhao Chen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Yuting Shi
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Kun Xia
- Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Li Meng
- Department of Radiology, Xiangya Hospital, Central South University, Changsha, China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,Laboratory of Medical Genetics, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Diseases, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China.,Parkinson's Disease Center, Beijing Institute for Brain Disorders, Beijing, China.,Collaborative Innovation Center for Brain Science, Shanghai, China.,Collaborative Innovation Center for Genetics and Development, Shanghai, China
| | - Rong Qiu
- School of Information Science and Engineering, Central South University, Changsha, China
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,Laboratory of Medical Genetics, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Diseases, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China.,Department of Neurology, Xinjiang Medical University, Urumchi, China
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34
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Goodman LD, Bonini NM. Repeat-associated non-AUG (RAN) translation mechanisms are running into focus for GGGGCC-repeat associated ALS/FTD. Prog Neurobiol 2019; 183:101697. [PMID: 31550516 DOI: 10.1016/j.pneurobio.2019.101697] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 08/31/2019] [Accepted: 09/17/2019] [Indexed: 12/12/2022]
Abstract
Many human diseases are associated with the expansion of repeat sequences within the genes. It has become clear that expressed disease transcripts bearing such long repeats can undergo translation, even in the absence of a canonical AUG start codon. Termed "RAN translation" for repeat associated non-AUG translation, this process is becoming increasingly prominent as a contributor to these disorders. Here we discuss mechanisms and variables that impact translation of the repeat sequences associated with the C9orf72 gene. Expansions of a G4C2 repeat within intron 1 of this gene are associated with the motor neuron disease ALS and dementia FTD, which comprise a clinical and pathological spectrum. RAN translation of G4C2 repeat expansions has been studied in cells in culture (ex vivo) and in the fly in vivo. Cellular states that lead to RAN translation, like stress, may be critical contributors to disease progression. Greater elucidation of the mechanisms that impact this process and the factors contributing will lead to greater understanding of the repeat expansion diseases, to the potential development of novel approaches to therapeutics, and to a greater understanding of how these players impact biological processes in the absence of disease.
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Affiliation(s)
- Lindsey D Goodman
- Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nancy M Bonini
- Neuroscience Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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35
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Wang ET, Treacy D, Eichinger K, Struck A, Estabrook J, Olafson H, Wang TT, Bhatt K, Westbrook T, Sedehizadeh S, Ward A, Day J, Brook D, Berglund JA, Cooper T, Housman D, Thornton C, Burge C. Transcriptome alterations in myotonic dystrophy skeletal muscle and heart. Hum Mol Genet 2019; 28:1312-1321. [PMID: 30561649 DOI: 10.1093/hmg/ddy432] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/30/2018] [Accepted: 12/10/2018] [Indexed: 11/12/2022] Open
Abstract
Myotonic dystrophy (dystrophia myotonica, DM) is a multi-systemic disease caused by expanded CTG or CCTG microsatellite repeats. Characterized by symptoms in muscle, heart and central nervous system, among others, it is one of the most variable diseases known. A major pathogenic event in DM is the sequestration of muscleblind-like proteins by CUG or CCUG repeat-containing RNAs transcribed from expanded repeats, and differences in the extent of MBNL sequestration dependent on repeat length and expression level may account for some portion of the variability. However, many other cellular pathways are reported to be perturbed in DM, and the severity of specific disease symptoms varies among individuals. To help understand this variability and facilitate research into DM, we generated 120 RNASeq transcriptomes from skeletal and heart muscle derived from healthy and DM1 biopsies and autopsies. A limited number of DM2 and Duchenne muscular dystrophy samples were also sequenced. We analyzed splicing and gene expression, identified tissue-specific changes in RNA processing and uncovered transcriptome changes strongly correlating with muscle strength. We created a web resource at http://DMseq.org that hosts raw and processed transcriptome data and provides a lightweight, responsive interface that enables browsing of processed data across the genome.
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Affiliation(s)
- Eric T Wang
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.,Koch Institute, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Molecular Genetics & Microbiology, University of Florida, Gainesville, FL, USA.,Center for NeuroGenetics, University of Florida, Gainesville, FL, USA.,University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Daniel Treacy
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Katy Eichinger
- Department of Neurology, University of Rochester, Rochester, NY, USA
| | - Adam Struck
- Department of Biochemistry, University of Oregon, Eugene, OR, USA
| | - Joseph Estabrook
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.,Koch Institute, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Molecular Genetics & Microbiology, University of Florida, Gainesville, FL, USA.,Center for NeuroGenetics, University of Florida, Gainesville, FL, USA.,University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Hailey Olafson
- Department of Molecular Genetics & Microbiology, University of Florida, Gainesville, FL, USA.,Center for NeuroGenetics, University of Florida, Gainesville, FL, USA.,University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Thomas T Wang
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kirti Bhatt
- Department of Neurology, University of Rochester, Rochester, NY, USA
| | - Tony Westbrook
- School of Life Sciences, Queen's Medical Center, University of Nottingham, Nottingham, UK
| | - Sam Sedehizadeh
- School of Life Sciences, Queen's Medical Center, University of Nottingham, Nottingham, UK
| | - Amanda Ward
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA
| | - John Day
- Department of Neurology, Stanford University, Palo Alto, CA, USA
| | - David Brook
- School of Life Sciences, Queen's Medical Center, University of Nottingham, Nottingham, UK
| | - J Andrew Berglund
- Department of Molecular Genetics & Microbiology, University of Florida, Gainesville, FL, USA.,Center for NeuroGenetics, University of Florida, Gainesville, FL, USA.,University of Florida Genetics Institute, University of Florida, Gainesville, FL, USA.,Department of Biochemistry, University of Oregon, Eugene, OR, USA
| | - Thomas Cooper
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA.,Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - David Housman
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.,Koch Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Charles Thornton
- Department of Neurology, University of Rochester, Rochester, NY, USA
| | - Christopher Burge
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.,Koch Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
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36
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Rodriguez CM, Todd PK. New pathologic mechanisms in nucleotide repeat expansion disorders. Neurobiol Dis 2019; 130:104515. [PMID: 31229686 DOI: 10.1016/j.nbd.2019.104515] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 06/07/2019] [Accepted: 06/19/2019] [Indexed: 12/14/2022] Open
Abstract
Tandem microsatellite repeats are common throughout the human genome and intrinsically unstable, exhibiting expansions and contractions both somatically and across generations. Instability in a small subset of these repeats are currently linked to human disease, although recent findings suggest more disease-causing repeats await discovery. These nucleotide repeat expansion disorders (NREDs) primarily affect the nervous system and commonly lead to neurodegeneration through toxic protein gain-of-function, protein loss-of-function, and toxic RNA gain-of-function mechanisms. However, the lines between these categories have blurred with recent findings of unconventional Repeat Associated Non-AUG (RAN) translation from putatively non-coding regions of the genome. Here we review two emerging topics in NREDs: 1) The mechanisms by which RAN translation occurs and its role in disease pathogenesis and 2) How nucleotide repeats as RNA and translated proteins influence liquid-liquid phase separation, membraneless organelle dynamics, and nucleocytoplasmic transport. We examine these topics with a particular eye on two repeats: the CGG repeat expansion responsible for Fragile X syndrome and Fragile X-associated Tremor Ataxia Syndrome (FXTAS) and the intronic GGGGCC repeat expansion in C9orf72, the most common inherited cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Our thesis is that these emerging disease mechanisms can inform a broader understanding of the native roles of microsatellites in cellular function and that aberrations in these native processes provide clues to novel therapeutic strategies for these currently untreatable disorders.
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Affiliation(s)
- C M Rodriguez
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; Department of Genetics, Stanford University, Stanford, CA, USA
| | - P K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA; VA Ann Arbor Healthcare System, Ann Arbor, MI, USA.
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Nguyen L, Cleary JD, Ranum LPW. Repeat-Associated Non-ATG Translation: Molecular Mechanisms and Contribution to Neurological Disease. Annu Rev Neurosci 2019; 42:227-247. [PMID: 30909783 DOI: 10.1146/annurev-neuro-070918-050405] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Microsatellite mutations involving the expansion of tri-, tetra-, penta-, or hexanucleotide repeats cause more than 40 different neurological disorders. Although, traditionally, the position of the repeat within or outside of an open reading frame has been used to focus research on disease mechanisms involving protein loss of function, protein gain of function, or RNA gain of function, the discoveries of bidirectional transcription and repeat-associated non-ATG (RAN) have blurred these distinctions. Here we review what is known about RAN proteins in disease, the mechanisms by which they are produced, and the novel therapeutic opportunities they provide.
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Affiliation(s)
- Lien Nguyen
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610, USA;
| | - John Douglas Cleary
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610, USA;
| | - Laura P W Ranum
- Center for NeuroGenetics, Department of Molecular Genetics and Microbiology, Genetics Institute, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610, USA;
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38
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Sparber P, Filatova A, Khantemirova M, Skoblov M. The role of long non-coding RNAs in the pathogenesis of hereditary diseases. BMC Med Genomics 2019; 12:42. [PMID: 30871545 PMCID: PMC6416829 DOI: 10.1186/s12920-019-0487-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Background Thousands of long non-coding RNA (lncRNA) genes are annotated in the human genome. Recent studies showed the key role of lncRNAs in a variety of fundamental cellular processes. Dysregulation of lncRNAs can drive tumorigenesis and they are now considered to be a promising therapeutic target in cancer. However, how lncRNAs contribute to the development of hereditary diseases in human is still mostly unknown. Results This review is focused on hereditary diseases in the pathogenesis of which long non-coding RNAs play an important role. Conclusions Fundamental research in the field of molecular genetics of lncRNA is necessary for a more complete understanding of their significance. Future research will help translate this knowledge into clinical practice which will not only lead to an increase in the diagnostic rate but also in the future can help with the development of etiotropic treatments for hereditary diseases.
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Affiliation(s)
- Peter Sparber
- Research Center for Medical Genetics, Moscow, Russia.
| | | | - Mira Khantemirova
- Novosibirsk State University, Novosibirsk, Russia.,Institute of Cytology and Genetics SB RAS, Novosibirsk, Russia
| | - Mikhail Skoblov
- Research Center for Medical Genetics, Moscow, Russia.,School of Biomedicine, Far Eastern Federal University, Vladivostok, Russia
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Lei XX, Liu Q, Lu Q, Huang Y, Zhou XQ, Sun HY, Wu LW, Cui LY, Zhang X. TTTCA repeat expansion causes familial cortical myoclonic tremor with epilepsy. Eur J Neurol 2018; 26:513-518. [PMID: 30351492 DOI: 10.1111/ene.13848] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 10/12/2018] [Indexed: 01/28/2023]
Abstract
BACKGROUND AND PURPOSE The aim was to investigate whether abnormal TTTTA and TTTCA repeat expansions in introns of SAMD12, TNRC6A and RAPGEF2 are involved in the pathogenesis of familial cortical myoclonic tremor with epilepsy (FCMTE). METHODS Five families diagnosed with FCMTE were included in the current genetic analysis. Whole-exome sequencing was performed in selected patients of each family. TTTTA and TTTCA expansions were examined by repeat-primed polymerase chain reaction. The clinical features of FCMTE were elicited as defined by the common genetic mechanism of 14 patients. RESULTS Abnormal TTTCA expansion was identified and co-segregated in all five FCMTE families, four inserted in SAMD12 and one in RAPGEF2. The insertion of expanded TTTCA was not found in 116 control alleles. TTTTA expansion in SAMD12 was detected in 90.9% (10/11) of patients or mutation carriers; TTTTA expansion in RAPGEF2 was not found. The onset age of myoclonic tremor was 27.4 ± 5.9 (19-37) and epilepsy usually presented around age 34. Focal and generalized seizures were witnessed with various origins recorded by electroencephalogram. Cognitive deficits were not common within the first 3 years after epilepsy onset. Emotional instability was reported by most patients. No patients showed any cerebellar deficits. Valproate added with clonazepam is effective in controlling seizures but cannot guarantee a complete remission of tremor. Repeat length showed intergenerational instability and was inversely correlated with age at onset of myoclonic tremor and epilepsy. CONCLUSIONS TTTCA expansion insertion is associated with FCMTE in Chinese families. The homogenous genetic mechanism allowed for a higher precision of FCMTE description.
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Affiliation(s)
- X X Lei
- Department of Neurology and Laboratory of Clinical Genetics, Peking Union Medical College Hospital (PUMCH), CAMS and PUMC, Beijing, China.,McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS) and Peking Union Medical College (PUMC), Beijing, China
| | - Q Liu
- Department of Neurology and Laboratory of Clinical Genetics, Peking Union Medical College Hospital (PUMCH), CAMS and PUMC, Beijing, China.,Neuroscience Center, Chinese Academy of Medical Sciences, Beijing, China
| | - Q Lu
- Department of Neurology and Laboratory of Clinical Genetics, Peking Union Medical College Hospital (PUMCH), CAMS and PUMC, Beijing, China
| | - Y Huang
- Department of Neurology and Laboratory of Clinical Genetics, Peking Union Medical College Hospital (PUMCH), CAMS and PUMC, Beijing, China
| | - X Q Zhou
- Department of Neurology and Laboratory of Clinical Genetics, Peking Union Medical College Hospital (PUMCH), CAMS and PUMC, Beijing, China
| | - H Y Sun
- Department of Neurology and Laboratory of Clinical Genetics, Peking Union Medical College Hospital (PUMCH), CAMS and PUMC, Beijing, China
| | - L W Wu
- Department of Neurology and Laboratory of Clinical Genetics, Peking Union Medical College Hospital (PUMCH), CAMS and PUMC, Beijing, China
| | - L Y Cui
- Department of Neurology and Laboratory of Clinical Genetics, Peking Union Medical College Hospital (PUMCH), CAMS and PUMC, Beijing, China.,Neuroscience Center, Chinese Academy of Medical Sciences, Beijing, China
| | - X Zhang
- Department of Neurology and Laboratory of Clinical Genetics, Peking Union Medical College Hospital (PUMCH), CAMS and PUMC, Beijing, China.,McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS) and Peking Union Medical College (PUMC), Beijing, China.,Neuroscience Center, Chinese Academy of Medical Sciences, Beijing, China
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Hofmann JW, Seeley WW, Huang EJ. RNA Binding Proteins and the Pathogenesis of Frontotemporal Lobar Degeneration. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2018; 14:469-495. [PMID: 30355151 DOI: 10.1146/annurev-pathmechdis-012418-012955] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Frontotemporal dementia is a group of early onset dementia syndromes linked to underlying frontotemporal lobar degeneration (FTLD) pathology that can be classified based on the formation of abnormal protein aggregates involving tau and two RNA binding proteins, TDP-43 and FUS. Although elucidation of the mechanisms leading to FTLD pathology is in progress, recent advances in genetics and neuropathology indicate that a majority of FTLD cases with proteinopathy involving RNA binding proteins show highly congruent genotype-phenotype correlations. Specifically, recent studies have uncovered the unique properties of the low-complexity domains in RNA binding proteins that can facilitate liquid-liquid phase separation in the formation of membraneless organelles. Furthermore, there is compelling evidence that mutations in FTLD genes lead to dysfunction in diverse cellular pathways that converge on the endolysosomal pathway, autophagy, and neuroinflammation. Together, these results provide key mechanistic insights into the pathogenesis and potential therapeutic targets of FTLD.
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Affiliation(s)
- Jeffrey W Hofmann
- Department of Pathology, University of California, San Francisco, California 94143, USA;
| | - William W Seeley
- Department of Pathology, University of California, San Francisco, California 94143, USA; .,Department of Neurology, University of California, San Francisco, California 94148, USA
| | - Eric J Huang
- Department of Pathology, University of California, San Francisco, California 94143, USA; .,Pathology Service 113B, Veterans Affairs Medical Center, San Francisco, California 94121, USA
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41
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Konopka A, Atkin JD. The Emerging Role of DNA Damage in the Pathogenesis of the C9orf72 Repeat Expansion in Amyotrophic Lateral Sclerosis. Int J Mol Sci 2018; 19:ijms19103137. [PMID: 30322030 PMCID: PMC6213462 DOI: 10.3390/ijms19103137] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/09/2018] [Accepted: 10/09/2018] [Indexed: 02/07/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, rapidly progressing neurodegenerative disease affecting motor neurons, and frontotemporal dementia (FTD) is a behavioural disorder resulting in early-onset dementia. Hexanucleotide (G4C2) repeat expansions in the gene encoding chromosome 9 open reading frame 72 (C9orf72) are the major cause of familial forms of both ALS (~40%) and FTD (~20%) worldwide. The C9orf72 repeat expansion is known to form abnormal nuclei acid structures, such as hairpins, G-quadruplexes, and R-loops, which are increasingly associated with human diseases involving microsatellite repeats. These configurations form during normal cellular processes, but if they persist they also damage DNA, and hence are a serious threat to genome integrity. It is unclear how the repeat expansion in C9orf72 causes ALS, but recent evidence implicates DNA damage in neurodegeneration. This may arise from abnormal nucleic acid structures, the greatly expanded C9orf72 RNA, or by repeat-associated non-ATG (RAN) translation, which generates toxic dipeptide repeat proteins. In this review, we detail recent advances implicating DNA damage in C9orf72-ALS. Furthermore, we also discuss increasing evidence that targeting these aberrant C9orf72 confirmations may have therapeutic value for ALS, thus revealing new avenues for drug discovery for this disorder.
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Affiliation(s)
- Anna Konopka
- Centre for MND Research, Department of Biomedical Sciences, Faculty of Medicine & Health Sciences, Macquarie University, Sydney, NSW 2109, Australia.
| | - Julie D Atkin
- Centre for MND Research, Department of Biomedical Sciences, Faculty of Medicine & Health Sciences, Macquarie University, Sydney, NSW 2109, Australia.
- La Trobe Institute for Molecular Science, Melbourne, VIC 3086, Australia.
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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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43
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Donlic A, Hargrove AE. Targeting RNA in mammalian systems with small molecules. WILEY INTERDISCIPLINARY REVIEWS. RNA 2018; 9:e1477. [PMID: 29726113 PMCID: PMC6002909 DOI: 10.1002/wrna.1477] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/06/2018] [Accepted: 03/06/2018] [Indexed: 12/18/2022]
Abstract
The recognition of RNA functions beyond canonical protein synthesis has challenged the central dogma of molecular biology. Indeed, RNA is now known to directly regulate many important cellular processes, including transcription, splicing, translation, and epigenetic modifications. The misregulation of these processes in disease has led to an appreciation of RNA as a therapeutic target. This potential was first recognized in bacteria and viruses, but discoveries of new RNA classes following the sequencing of the human genome have invigorated exploration of its disease-related functions in mammals. As stable structure formation is evolving as a hallmark of mammalian RNAs, the prospect of utilizing small molecules to specifically probe the function of RNA structural domains and their interactions is gaining increased recognition. To date, researchers have discovered bioactive small molecules that modulate phenotypes by binding to expanded repeats, microRNAs, G-quadruplex structures, and RNA splice sites in neurological disorders, cancers, and other diseases. The lessons learned from achieving these successes both call for additional studies and encourage exploration of the plethora of mammalian RNAs whose precise mechanisms of action remain to be elucidated. Efforts toward understanding fundamental principles of small molecule-RNA recognition combined with advances in methodology development should pave the way toward targeting emerging RNA classes such as long noncoding RNAs. Together, these endeavors can unlock the full potential of small molecule-based probing of RNA-regulated processes and enable us to discover new biology and underexplored avenues for therapeutic intervention in human disease. This article is categorized under: RNA Methods > RNA Analyses In Vitro and In Silico RNA Interactions with Proteins and Other Molecules > Small Molecule-RNA Interactions RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Anita Donlic
- Department of Chemistry, Duke University, Durham, North Carolina
| | - Amanda E Hargrove
- Department of Chemistry, Duke University, Durham, North Carolina
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina
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44
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Pan F, Man VH, Roland C, Sagui C. Structure and Dynamics of DNA and RNA Double Helices Obtained from the CCG and GGC Trinucleotide Repeats. J Phys Chem B 2018; 122:4491-4512. [PMID: 29617130 DOI: 10.1021/acs.jpcb.8b01658] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Expansions of both GGC and CCG sequences lead to a number of expandable, trinucleotide repeat (TR) neurodegenerative diseases. Understanding of these diseases involves, among other things, the structural characterization of the atypical DNA and RNA secondary structures. We have performed molecular dynamics simulations of (GCC) n and (GGC) n homoduplexes in order to characterize their conformations, stability, and dynamics. Each TR has two reading frames, which results in eight nonequivalent RNA/DNA homoduplexes, characterized by CpG or GpC steps between the Watson-Crick base pairs. Free energy maps for the eight homoduplexes indicate that the C-mismatches prefer anti-anti conformations, while G-mismatches prefer anti-syn conformations. Comparison between three modifications of the DNA AMBER force field shows good agreement for the mismatch free energy maps. The mismatches in DNA-GCC (but not CCG) are extrahelical, forming an extended e-motif. The mismatched duplexes exhibit characteristic sequence-dependent step twist, with strong variations in the G-rich sequences and the e-motif. The distribution of Na+ is highly localized around the mismatches, especially G-mismatches. In the e-motif, there is strong Na+ binding by two G(N7) atoms belonging to the pseudo GpC step created when cytosines are extruded and by extrahelical cytosines. Finally, we used a novel technique based on fast melting by means of an infrared laser pulse to classify the relative stability of the different DNA-CCG and -GGC homoduplexes.
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Affiliation(s)
- Feng Pan
- Department of Physics , North Carolina State University , Raleigh , North Carolina 27695-8202 , United States
| | - Viet Hoang Man
- Department of Physics , North Carolina State University , Raleigh , North Carolina 27695-8202 , United States
| | - Christopher Roland
- Department of Physics , North Carolina State University , Raleigh , North Carolina 27695-8202 , United States
| | - Celeste Sagui
- Department of Physics , North Carolina State University , Raleigh , North Carolina 27695-8202 , United States
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45
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Cheng W, Wang S, Mestre AA, Fu C, Makarem A, Xian F, Hayes LR, Lopez-Gonzalez R, Drenner K, Jiang J, Cleveland DW, Sun S. C9ORF72 GGGGCC repeat-associated non-AUG translation is upregulated by stress through eIF2α phosphorylation. Nat Commun 2018; 9:51. [PMID: 29302060 PMCID: PMC5754368 DOI: 10.1038/s41467-017-02495-z] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 12/01/2017] [Indexed: 01/04/2023] Open
Abstract
Hexanucleotide repeat expansion in C9ORF72 is the most frequent cause of both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Here we demonstrate that the repeat-associated non-AUG (RAN) translation of (GGGGCC) n -containing RNAs into poly-dipeptides can initiate in vivo without a 5'-cap. The primary RNA substrate for RAN translation of C9ORF72 sense repeats is shown to be the spliced first intron, following its excision from the initial pre-mRNA and transport to the cytoplasm. Cap-independent RAN translation is shown to be upregulated by various stress stimuli through phosphorylation of the α subunit of eukaryotic initiation factor-2 (eIF2α), the core event of an integrated stress response (ISR). Compounds inhibiting phospho-eIF2α-signaling pathways are shown to suppress RAN translation. Since the poly-dipeptides can themselves induce stress, these findings support a feedforward loop with initial repeat-mediated toxicity enhancing RAN translation and subsequent production of additional poly-dipeptides through ISR, thereby promoting progressive disease.
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Affiliation(s)
- Weiwei Cheng
- Department of Pathology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Shaopeng Wang
- Department of Pathology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Alexander A Mestre
- Department of Pathology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Chenglai Fu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Andres Makarem
- Department of Pathology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Fengfan Xian
- Department of Pathology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Lindsey R Hayes
- Brain Science Institute and Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Rodrigo Lopez-Gonzalez
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Kevin Drenner
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, 92093, USA
| | - Jie Jiang
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, 92093, USA
| | - Don W Cleveland
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, 92093, USA
| | - Shuying Sun
- Department of Pathology and Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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Abstract
This review by Kearse and Wilusz discusses the profound impact of non-AUG start codons in eukaryotic translation. It describes how misregulation of non-AUG initiation events contributes to multiple human diseases, including cancer and neurodegeneration, and how modulation of non-AUG usage may represent a novel therapeutic strategy. Although it was long thought that eukaryotic translation almost always initiates at an AUG start codon, recent advancements in ribosome footprint mapping have revealed that non-AUG start codons are used at an astonishing frequency. These non-AUG initiation events are not simply errors but instead are used to generate or regulate proteins with key cellular functions; for example, during development or stress. Misregulation of non-AUG initiation events contributes to multiple human diseases, including cancer and neurodegeneration, and modulation of non-AUG usage may represent a novel therapeutic strategy. It is thus becoming increasingly clear that start codon selection is regulated by many trans-acting initiation factors as well as sequence/structural elements within messenger RNAs and that non-AUG translation has a profound impact on cellular states.
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Affiliation(s)
- Michael G Kearse
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, 19104 USA
| | - Jeremy E Wilusz
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, 19104 USA
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47
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Intrinsic Disorder in Proteins with Pathogenic Repeat Expansions. Molecules 2017; 22:molecules22122027. [PMID: 29186753 PMCID: PMC6149999 DOI: 10.3390/molecules22122027] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 11/18/2017] [Accepted: 11/21/2017] [Indexed: 11/18/2022] Open
Abstract
Intrinsically disordered proteins and proteins with intrinsically disordered regions have been shown to be highly prevalent in disease. Furthermore, disease-causing expansions of the regions containing tandem amino acid repeats often push repetitive proteins towards formation of irreversible aggregates. In fact, in disease-relevant proteins, the increased repeat length often positively correlates with the increased aggregation efficiency and the increased disease severity and penetrance, being negatively correlated with the age of disease onset. The major categories of repeat extensions involved in disease include poly-glutamine and poly-alanine homorepeats, which are often times located in the intrinsically disordered regions, as well as repeats in non-coding regions of genes typically encoding proteins with ordered structures. Repeats in such non-coding regions of genes can be expressed at the mRNA level. Although they can affect the expression levels of encoded proteins, they are not translated as parts of an affected protein and have no effect on its structure. However, in some cases, the repetitive mRNAs can be translated in a non-canonical manner, generating highly repetitive peptides of different length and amino acid composition. The repeat extension-caused aggregation of a repetitive protein may represent a pivotal step for its transformation into a proteotoxic entity that can lead to pathology. The goals of this article are to systematically analyze molecular mechanisms of the proteinopathies caused by the poly-glutamine and poly-alanine homorepeat expansion, as well as by the polypeptides generated as a result of the microsatellite expansions in non-coding gene regions and to examine the related proteins. We also present results of the analysis of the prevalence and functional roles of intrinsic disorder in proteins associated with pathological repeat expansions.
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48
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Kiliszek A, Blaszczyk L, Kierzek R, Rypniewski W. Stabilization of RNA hairpins using non-nucleotide linkers and circularization. Nucleic Acids Res 2017; 45:e92. [PMID: 28334744 PMCID: PMC5449636 DOI: 10.1093/nar/gkx122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 02/09/2017] [Indexed: 12/21/2022] Open
Abstract
An RNA hairpin is an essential structural element of RNA. Hairpins play crucial roles in gene expression and intermolecular recognition but are also involved in the pathogenesis of some congenital diseases. Structural studies of the hairpin motifs are impeded by their thermodynamic instability, as they tend to unfold to form duplexes, especially at high concentrations required for crystallography or nuclear magnetic resonance spectroscopy. We have elaborated techniques to stabilize the RNA hairpins by linking the free ends of the RNA strand at the base of the hairpin stem. One method involves stilbene diether or hexaethylene glycol linkers and circularization by T4 RNA ligase. Another method uses click chemistry to stitch the RNA ends with a triazole linker. Both techniques are efficient and easy to perform. They should be useful in making stable, biologically relevant RNA constructs for structural studies.
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Affiliation(s)
- Agnieszka Kiliszek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Leszek Blaszczyk
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Ryszard Kierzek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Wojciech Rypniewski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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Seixas AI, Loureiro JR, Costa C, Ordóñez-Ugalde A, Marcelino H, Oliveira CL, Loureiro JL, Dhingra A, Brandão E, Cruz VT, Timóteo A, Quintáns B, Rouleau GA, Rizzu P, Carracedo Á, Bessa J, Heutink P, Sequeiros J, Sobrido MJ, Coutinho P, Silveira I. A Pentanucleotide ATTTC Repeat Insertion in the Non-coding Region of DAB1, Mapping to SCA37, Causes Spinocerebellar Ataxia. Am J Hum Genet 2017; 101:87-103. [PMID: 28686858 DOI: 10.1016/j.ajhg.2017.06.007] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 06/13/2017] [Indexed: 01/01/2023] Open
Abstract
Advances in human genetics in recent years have largely been driven by next-generation sequencing (NGS); however, the discovery of disease-related gene mutations has been biased toward the exome because the large and very repetitive regions that characterize the non-coding genome remain difficult to reach by that technology. For autosomal-dominant spinocerebellar ataxias (SCAs), 28 genes have been identified, but only five SCAs originate from non-coding mutations. Over half of SCA-affected families, however, remain without a genetic diagnosis. We used genome-wide linkage analysis, NGS, and repeat analysis to identify an (ATTTC)n insertion in a polymorphic ATTTT repeat in DAB1 in chromosomal region 1p32.2 as the cause of autosomal-dominant SCA; this region has been previously linked to SCA37. The non-pathogenic and pathogenic alleles have the configurations [(ATTTT)7-400] and [(ATTTT)60-79(ATTTC)31-75(ATTTT)58-90], respectively. (ATTTC)n insertions are present on a distinct haplotype and show an inverse correlation between size and age of onset. In the DAB1-oriented strand, (ATTTC)n is located in 5' UTR introns of cerebellar-specific transcripts arising mostly during human fetal brain development from the usage of alternative promoters, but it is maintained in the adult cerebellum. Overexpression of the transfected (ATTTC)58 insertion, but not (ATTTT)n, leads to abnormal nuclear RNA accumulation. Zebrafish embryos injected with RNA of the (AUUUC)58 insertion, but not (AUUUU)n, showed lethal developmental malformations. Together, these results establish an unstable repeat insertion in DAB1 as a cause of cerebellar degeneration; on the basis of the genetic and phenotypic evidence, we propose this mutation as the molecular basis for SCA37.
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Thornton CA, Wang E, Carrell EM. Myotonic dystrophy: approach to therapy. Curr Opin Genet Dev 2017; 44:135-140. [PMID: 28376341 PMCID: PMC5447481 DOI: 10.1016/j.gde.2017.03.007] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 02/25/2017] [Accepted: 03/13/2017] [Indexed: 01/16/2023]
Abstract
Myotonic dystrophy (DM) is a dominantly-inherited genetic disorder affecting skeletal muscle, heart, brain, and other organs. DM type 1 is caused by expansion of a CTG triplet repeat in DMPK, whereas DM type 2 is caused by expansion of a CCTG tetramer repeat in CNBP. In both cases the DM mutations lead to expression of dominant-acting RNAs. Studies of RNA toxicity have now revealed novel mechanisms and new therapeutic targets. Preclinical data have suggested that RNA dominance is responsive to therapeutic intervention and that DM therapy can be approached at several different levels. Here we review recent efforts to alleviate RNA toxicity in DM.
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Affiliation(s)
- Charles A Thornton
- Department of Neurology, University of Rochester, Rochester 14642, NY, United States.
| | - Eric Wang
- Department of Molecular Genetics & Microbiology, Center for NeuroGenetics, University of Florida, Gainesville, FL, United States
| | - Ellie M Carrell
- Department of Neurology, University of Rochester, Rochester 14642, NY, United States
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