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Tanudisastro HA, Deveson IW, Dashnow H, MacArthur DG. Sequencing and characterizing short tandem repeats in the human genome. Nat Rev Genet 2024; 25:460-475. [PMID: 38366034 DOI: 10.1038/s41576-024-00692-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2023] [Indexed: 02/18/2024]
Abstract
Short tandem repeats (STRs) are highly polymorphic sequences throughout the human genome that are composed of repeated copies of a 1-6-bp motif. Over 1 million variable STR loci are known, some of which regulate gene expression and influence complex traits, such as height. Moreover, variants in at least 60 STR loci cause genetic disorders, including Huntington disease and fragile X syndrome. Accurately identifying and genotyping STR variants is challenging, in particular mapping short reads to repetitive regions and inferring expanded repeat lengths. Recent advances in sequencing technology and computational tools for STR genotyping from sequencing data promise to help overcome this challenge and solve genetically unresolved cases and the 'missing heritability' of polygenic traits. Here, we compare STR genotyping methods, analytical tools and their applications to understand the effect of STR variation on health and disease. We identify emergent opportunities to refine genotyping and quality-control approaches as well as to integrate STRs into variant-calling workflows and large cohort analyses.
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Affiliation(s)
- Hope A Tanudisastro
- Centre for Population Genomics, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- Centre for Population Genomics, Murdoch Children's Research Institute, Melbourne, Victoria, Australia
- Faculty of Medicine and Health, University of New South Wales, Sydney, New South Wales, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Ira W Deveson
- Faculty of Medicine and Health, University of New South Wales, Sydney, New South Wales, Australia
- Genomics and Inherited Disease Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Harriet Dashnow
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA.
| | - Daniel G MacArthur
- Centre for Population Genomics, Garvan Institute of Medical Research, Sydney, New South Wales, Australia.
- Centre for Population Genomics, Murdoch Children's Research Institute, Melbourne, Victoria, Australia.
- Faculty of Medicine and Health, University of New South Wales, Sydney, New South Wales, Australia.
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2
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Cui ZT, Mao ZT, Yang R, Li JJ, Jia SS, Zhao JL, Zhong FT, Yu P, Dong M. Spinocerebellar ataxias: from pathogenesis to recent therapeutic advances. Front Neurosci 2024; 18:1422442. [PMID: 38894941 PMCID: PMC11185097 DOI: 10.3389/fnins.2024.1422442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 05/08/2024] [Indexed: 06/21/2024] Open
Abstract
Spinocerebellar ataxia is a phenotypically and genetically heterogeneous group of autosomal dominant-inherited degenerative disorders. The gene mutation spectrum includes dynamic expansions, point mutations, duplications, insertions, and deletions of varying lengths. Dynamic expansion is the most common form of mutation. Mutations often result in indistinguishable clinical phenotypes, thus requiring validation using multiple genetic testing techniques. Depending on the type of mutation, the pathogenesis may involve proteotoxicity, RNA toxicity, or protein loss-of-function. All of which may disrupt a range of cellular processes, such as impaired protein quality control pathways, ion channel dysfunction, mitochondrial dysfunction, transcriptional dysregulation, DNA damage, loss of nuclear integrity, and ultimately, impairment of neuronal function and integrity which causes diseases. Many disease-modifying therapies, such as gene editing technology, RNA interference, antisense oligonucleotides, stem cell technology, and pharmacological therapies are currently under clinical trials. However, the development of curative approaches for genetic diseases remains a global challenge, beset by technical, ethical, and other challenges. Therefore, the study of the pathogenesis of spinocerebellar ataxia is of great importance for the sustained development of disease-modifying molecular therapies.
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Affiliation(s)
- Zi-Ting Cui
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Zong-Tao Mao
- Department of Plastic and Reconstructive Surgery, The First Hospital of Jilin University, Changchun, China
| | - Rong Yang
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Jia-Jia Li
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Shan-Shan Jia
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Jian-Li Zhao
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Fang-Tian Zhong
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Peng Yu
- Department of Ophthalmology, the Second Hospital of Jilin University, Changchun, China
| | - Ming Dong
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
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3
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Morikawa T, Miura S, Uchiyama Y, Hiruki S, Sun Y, Fujioka R, Shibata H. Hexanucleotide repeat expansion in SCA36 reduces the expression of genes involved in ribosome biosynthesis and protein translation. J Hum Genet 2024:10.1038/s10038-024-01260-7. [PMID: 38811808 DOI: 10.1038/s10038-024-01260-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 05/15/2024] [Accepted: 05/21/2024] [Indexed: 05/31/2024]
Abstract
Hereditary spinocerebellar ataxia (SCA) is a group of clinically and genetically heterogeneous inherited disorders characterized by slowly progressive cerebellar ataxia. We ascertained a Japanese pedigree with autosomal dominant SCA comprising four family members, including two patients. We identified a GGCCTG repeat expansion of intron 1 in the NOP56 gene by Southern blotting, resulting in a molecular diagnosis of SCA36. RNA sequencing using peripheral blood revealed that the expression of genes involved in ribosomal organization and translation was decreased in patients carrying the GGCCTG repeat expansion. Genes involved in pathways associated with ribosomal organization and translation were enriched and differentially expressed in the patients. We propose a novel hypothesis that the GGCCTG repeat expansion contributes to the pathogenesis of SCA36 by causing a global disruption of translation resulting from ribosomal dysfunction.
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Affiliation(s)
- Takuya Morikawa
- Division of Genomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Shiroh Miura
- Department of Neurology and Geriatric Medicine, Ehime University Graduate School of Medicine, Shitsukawa, Toon, 791-0295, Japan
| | - Yusuke Uchiyama
- Department of Radiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
| | - Shigeyoshi Hiruki
- Division of Genomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Yinrui Sun
- Division of Genomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Ryuta Fujioka
- Department of Food and Nutrition, Beppu University Junior College, 82, Kitaishigaki, Oita, 874-8501, Japan
| | - Hiroki Shibata
- Division of Genomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
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4
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Kumar M, Sahni S, A V, Kumar D, Kushwah N, Goel D, Kapoor H, Srivastava AK, Faruq M. Molecular clues unveiling spinocerebellar ataxia type-12 pathogenesis. iScience 2024; 27:109768. [PMID: 38711441 PMCID: PMC11070597 DOI: 10.1016/j.isci.2024.109768] [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: 07/27/2023] [Revised: 01/31/2024] [Accepted: 04/15/2024] [Indexed: 05/08/2024] Open
Abstract
Spinocerebellar Ataxia type-12 (SCA12) is a neurodegenerative disease caused by tandem CAG repeat expansion in the 5'-UTR/non-coding region of PPP2R2B. Molecular pathology of SCA12 has not been studied in the context of CAG repeats, and no appropriate models exist. We found in human SCA12-iPSC-derived neuronal lineage that expanded CAG in PPP2R2B transcript forms nuclear RNA foci and were found to sequester variety of proteins. Further, the ectopic expression of transcript containing varying length of CAG repeats exhibits non-canonical repeat-associated non-AUG (RAN) translation in multiple frames in HEK293T cells, which was further validated in patient-derived neural stem cells using specific antibodies. mRNA sequencing of the SCA12 and control neurons have shown a network of crucial transcription factors affecting neural fate, in addition to alteration of various signaling pathways involved in neurodevelopment. Altogether, this study identifies the molecular signatures of SCA12 disorder using patient-derived neuronal cell lines.
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Affiliation(s)
- Manish Kumar
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR -IGIB), Mall Road, Delhi 110007, India
- CSIR-HRDC Campus, Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Shweta Sahni
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR -IGIB), Mall Road, Delhi 110007, India
- Department of Neurology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Vivekanand A
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR -IGIB), Mall Road, Delhi 110007, India
- CSIR-HRDC Campus, Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Deepak Kumar
- Division of Genomics and Molecular Medicine, CSIR - Institute of Genomics and Integrative Biology (IGIB), New Delhi 110007, India
- Department of Zoology, University of Allahabad, Prayagraj, Uttar Pradesh 211002, India
| | - Neetu Kushwah
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR -IGIB), Mall Road, Delhi 110007, India
| | - Divya Goel
- Department of Pharmacology, School of Pharmaceutical Education & Research (SPER), Jamia Hamdard, New Delhi 110062, India
| | - Himanshi Kapoor
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR -IGIB), Mall Road, Delhi 110007, India
| | - Achal K. Srivastava
- Department of Neurology, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Mohammed Faruq
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology (CSIR -IGIB), Mall Road, Delhi 110007, India
- CSIR-HRDC Campus, Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
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5
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Pilotto F, Del Bondio A, Puccio H. Hereditary Ataxias: From Bench to Clinic, Where Do We Stand? Cells 2024; 13:319. [PMID: 38391932 PMCID: PMC10886822 DOI: 10.3390/cells13040319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/24/2024] Open
Abstract
Cerebellar ataxias are a wide heterogeneous group of movement disorders. Within this broad umbrella of diseases, there are both genetics and sporadic forms. The clinical presentation of these conditions can exhibit a diverse range of symptoms across different age groups, spanning from pure cerebellar manifestations to sensory ataxia and multisystemic diseases. Over the last few decades, advancements in our understanding of genetics and molecular pathophysiology related to both dominant and recessive ataxias have propelled the field forward, paving the way for innovative therapeutic strategies aimed at preventing and arresting the progression of these diseases. Nevertheless, the rarity of certain forms of ataxia continues to pose challenges, leading to limited insights into the etiology of the disease and the identification of target pathways. Additionally, the lack of suitable models hampers efforts to comprehensively understand the molecular foundations of disease's pathophysiology and test novel therapeutic interventions. In the following review, we describe the epidemiology, symptomatology, and pathological progression of hereditary ataxia, including both the prevalent and less common forms of these diseases. Furthermore, we illustrate the diverse molecular pathways and therapeutic approaches currently undergoing investigation in both pre-clinical studies and clinical trials. Finally, we address the existing and anticipated challenges within this field, encompassing both basic research and clinical endeavors.
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Affiliation(s)
- Federica Pilotto
- Institut Neuromyogène, Pathophysiology and Genetics of Neuron and Muscle, Inserm U1315, CNRS-Université Claude Bernard Lyon 1 UMR5261, 69008 Lyon, France
| | - Andrea Del Bondio
- Institut Neuromyogène, Pathophysiology and Genetics of Neuron and Muscle, Inserm U1315, CNRS-Université Claude Bernard Lyon 1 UMR5261, 69008 Lyon, France
| | - Hélène Puccio
- Institut Neuromyogène, Pathophysiology and Genetics of Neuron and Muscle, Inserm U1315, CNRS-Université Claude Bernard Lyon 1 UMR5261, 69008 Lyon, France
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Maltby CJ, Krans A, Grudzien SJ, Palacios Y, Muiños J, Suárez A, Asher M, Khurana V, Barmada SJ, Dijkstra AA, Todd PK. AAGGG repeat expansions trigger RFC1-independent synaptic dysregulation in human CANVAS Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.13.571345. [PMID: 38168171 PMCID: PMC10760133 DOI: 10.1101/2023.12.13.571345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a late onset, recessively inherited neurodegenerative disorder caused by biallelic, non-reference pentameric AAGGG(CCCTT) repeat expansions within the second intron of replication factor complex subunit 1 (RFC1). To investigate how these repeats cause disease, we generated CANVAS patient induced pluripotent stem cell (iPSC) derived neurons (iNeurons) and utilized calcium imaging and transcriptomic analysis to define repeat-elicited gain-of-function and loss-of-function contributions to neuronal toxicity. AAGGG repeat expansions do not alter neuronal RFC1 splicing, expression, or DNA repair pathway functions. In reporter assays, AAGGG repeats are translated into pentapeptide repeat proteins that selectively accumulate in CANVAS patient brains. However, neither these proteins nor repeat RNA foci were detected in iNeurons, and overexpression of these repeats in isolation did not induce neuronal toxicity. CANVAS iNeurons exhibit defects in neuronal development and diminished synaptic connectivity that is rescued by CRISPR deletion of a single expanded allele. These phenotypic deficits were not replicated by knockdown of RFC1 in control neurons and were not rescued by ectopic expression of RFC1. These findings support a repeat-dependent but RFC1-independent cause of neuronal dysfunction in CANVAS, with important implications for therapeutic development in this currently untreatable condition.
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Affiliation(s)
- Connor J. Maltby
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI, USA
| | - Samantha J. Grudzien
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Yomira Palacios
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Postbaccalaureate Research Education Program, University of Michigan, Ann Arbor, MI, USA
| | - Jessica Muiños
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- UM SMART Undergraduate Summer Program, University of Michigan, Ann Arbor, MI, USA
| | - Andrea Suárez
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Postbaccalaureate Research Education Program, University of Michigan, Ann Arbor, MI, USA
| | - Melissa Asher
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Vikram Khurana
- Department of Neurology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Sami J. Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Anke A. Dijkstra
- Department of Pathology, Amsterdam UMC, Amsterdam Neuroscience, Amsterdam, The Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Peter K. Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI, USA
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7
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Nikom D, Zheng S. Alternative splicing in neurodegenerative disease and the promise of RNA therapies. Nat Rev Neurosci 2023; 24:457-473. [PMID: 37336982 DOI: 10.1038/s41583-023-00717-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2023] [Indexed: 06/21/2023]
Abstract
Alternative splicing generates a myriad of RNA products and protein isoforms of different functions from a single gene. Dysregulated alternative splicing has emerged as a new mechanism broadly implicated in the pathogenesis of neurodegenerative diseases such as Alzheimer disease, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson disease and repeat expansion diseases. Understanding the mechanisms and functional outcomes of abnormal splicing in neurological disorders is vital in developing effective therapies to treat mis-splicing pathology. In this Review, we discuss emerging research and evidence of the roles of alternative splicing defects in major neurodegenerative diseases and summarize the latest advances in RNA-based therapeutic strategies to target these disorders.
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Affiliation(s)
- David Nikom
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, USA
- Center for RNA Biology and Medicine, University of California, Riverside, Riverside, CA, USA
| | - Sika Zheng
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, USA.
- Center for RNA Biology and Medicine, University of California, Riverside, Riverside, CA, USA.
- Division of Biomedical Sciences, University of California, Riverside, Riverside, CA, USA.
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8
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Chang YS, Hsu MH, Chung CC, Chen HD, Tu SJ, Lee YT, Yen JC, Liu TC, Chang JG. Comprehensive Analysis and Drug Modulation of Human Endogenous Retrovirus in Hepatocellular Carcinomas. Cancers (Basel) 2023; 15:3664. [PMID: 37509325 PMCID: PMC10377948 DOI: 10.3390/cancers15143664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/12/2023] [Accepted: 07/16/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND Human endogenous retroviruses (HERVs) play an important role in the development of cancer and many diseases. Here, we comprehensively explored the impact of HERVs on hepatocellular carcinomas (HCCs). METHODS We employed Telescope to identify HERVs and quantify their expression in the total RNA sequencing data obtained from 254 HCC samples, comprising 254 tumor tissues and 34 matched normal tissues. RESULTS In total, 3357 locus-specific activations of HERVs were differentially expressed, and 180 were correlated with patient survival. Using these 180 HERVs for classification, we found four subgroups with survival correlation. Higher expression levels of the 180 HERVs were correlated with poorer survival, while age, AFP, some mutations, and copy and structural variants differed among subgroups. The differential expression of host genes in high expression of these 180 HERVs primarily involved the activation of pathways related to immunity and infection, lipid and atherosclerosis, MAPK and NF-kB signaling, and cytokine-cytokine receptor interactions. Conversely, there was a suppression of pathways associated with RNA processing, including nucleocytoplasmic transport, surveillance and ribosome biogenesis, and transcriptional misregulation in cancer pathways. Almost all genes involved in HERV activation restriction, KRAB zinc finger proteins, RNA nucleocytoplasmic transport, stemness, HLA and antigen processing and presentation, and immune checkpoints were overexpressed in cancerous tissues, and many over-expressed HERV-related nearby genes were correlated with high HERV activation and poor survival. Twenty-three immune and stromal cells showed higher expression in non-cancerous than cancerous tissues, and seven were correlated with HERV activation. Small-molecule modulation of alternative splicing (AS) altered the expression of survival-related HERVs and their activation-related genes, as well as nearby genes. CONCLUSION Comprehensive and integrated approaches for evaluating HERV expression and their correlation with specific pathways have the potential to provide new companion diagnostics and therapeutic strategies for HCC.
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Affiliation(s)
- Ya-Sian Chang
- Center for Precision Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- Epigenome Research Center, China Medical University Hospital, Taichung 40447, Taiwan
- Department of Laboratory Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- School of Medicine, China Medical University, Taichung 40402, Taiwan
| | - Ming-Hon Hsu
- Center for Precision Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- Epigenome Research Center, China Medical University Hospital, Taichung 40447, Taiwan
- Department of Laboratory Medicine, China Medical University Hospital, Taichung 40447, Taiwan
| | - Chin-Chun Chung
- Center for Precision Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- Epigenome Research Center, China Medical University Hospital, Taichung 40447, Taiwan
| | - Hong-Da Chen
- Center for Precision Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- Epigenome Research Center, China Medical University Hospital, Taichung 40447, Taiwan
- Department of Laboratory Medicine, China Medical University Hospital, Taichung 40447, Taiwan
| | - Siang-Jyun Tu
- Center for Precision Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- Epigenome Research Center, China Medical University Hospital, Taichung 40447, Taiwan
- Department of Laboratory Medicine, China Medical University Hospital, Taichung 40447, Taiwan
| | - Ya-Ting Lee
- Center for Precision Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- Epigenome Research Center, China Medical University Hospital, Taichung 40447, Taiwan
| | - Ju-Chen Yen
- Center for Precision Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- Epigenome Research Center, China Medical University Hospital, Taichung 40447, Taiwan
| | - Ta-Chih Liu
- Department of Hematology-Oncology, Chang Bing Show Chwan Memorial Hospital, Changhua 50544, Taiwan
| | - Jan-Gowth Chang
- Center for Precision Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- Epigenome Research Center, China Medical University Hospital, Taichung 40447, Taiwan
- Department of Laboratory Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- School of Medicine, China Medical University, Taichung 40402, Taiwan
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9
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Cuccurullo C, Striano P, Coppola A. Familial Adult Myoclonus Epilepsy: A Non-Coding Repeat Expansion Disorder of Cerebellar-Thalamic-Cortical Loop. Cells 2023; 12:1617. [PMID: 37371086 DOI: 10.3390/cells12121617] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/07/2023] [Accepted: 06/09/2023] [Indexed: 06/29/2023] Open
Abstract
Familial adult myoclonus Epilepsy (FAME) is a non-coding repeat expansion disorder that has been reported under different acronyms and initially linked to four main loci: FAME1 (8q23.3-q24.1), FAME 2 (2p11.1-q12.1), FAME3 (5p15.31-p15.1), and FAME4 (3q26.32-3q28). To date, it is known that the genetic mechanism underlying FAME consists of the expansion of similar non-coding pentanucleotide repeats, TTTCA and TTTTA, in different genes. FAME is characterized by cortical tremor and myoclonus usually manifesting within the second decade of life, and infrequent seizures by the third or fourth decade. Cortical tremor is the core feature of FAME and is considered part of a spectrum of cortical myoclonus. Neurophysiological investigations as jerk-locked back averaging (JLBA) and corticomuscular coherence analysis, giant somatosensory evoked potentials (SEPs), and the presence of long-latency reflex I (or C reflex) at rest support cortical tremor as the result of the sensorimotor cortex hyperexcitability. Furthermore, the application of transcranial magnetic stimulation (TMS) protocols in FAME patients has recently shown that inhibitory circuits are also altered within the primary somatosensory cortex and the concomitant involvement of subcortical networks. Moreover, neuroimaging studies and postmortem autoptic studies indicate cerebellar alterations and abnormal functional connectivity between the cerebellum and cerebrum in FAME. Accordingly, the pathophysiological mechanism underlying FAME has been hypothesized to reside in decreased sensorimotor cortical inhibition through dysfunction of the cerebellar-thalamic-cortical loop, secondary to primary cerebellar pathology. In this context, the non-coding pentameric expansions have been proposed to cause cerebellar damage through an RNA-mediated toxicity mechanism. The elucidation of the underlying pathological mechanisms of FAME paves the way to novel therapeutic possibilities, such as RNA-targeting treatments, possibly applicable to other neurodegenerative non-coding disorders.
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Affiliation(s)
- Claudia Cuccurullo
- Department of Neuroscience, Reproductive Sciences and Odontostomatology, Federico II University of Naples, 80131 Naples, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, 16126 Genova, Italy
| | - Antonietta Coppola
- Department of Neuroscience, Reproductive Sciences and Odontostomatology, Federico II University of Naples, 80131 Naples, Italy
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10
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Quek RT, Hardy KS, Walker SG, Nguyen DT, de Almeida
Magalhães T, Salic A, Gopalakrishnan SM, Silver PA, Mitchison TJ. Screen for Modulation of Nucleocapsid Protein Condensation Identifies Small Molecules with Anti-Coronavirus Activity. ACS Chem Biol 2023; 18:583-594. [PMID: 36795767 PMCID: PMC9942534 DOI: 10.1021/acschembio.2c00908] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/03/2023] [Indexed: 02/17/2023]
Abstract
Biomolecular condensates formed by liquid-liquid phase separation have been implicated in multiple diseases. Modulation of condensate dynamics by small molecules has therapeutic potential, but so far, few condensate modulators have been disclosed. The SARS-CoV-2 nucleocapsid (N) protein forms phase-separated condensates that are hypothesized to play critical roles in viral replication, transcription, and packaging, suggesting that N condensation modulators might have anti-coronavirus activity across multiple strains and species. Here, we show that N proteins from all seven human coronaviruses (HCoVs) vary in their tendency to undergo phase separation when expressed in human lung epithelial cells. We developed a cell-based high-content screening platform and identified small molecules that both promote and inhibit condensation of SARS-CoV-2 N. Interestingly, these host-targeted small molecules exhibited condensate-modulatory effects across all HCoV Ns. Some have also been reported to exhibit antiviral activity against SARS-CoV-2, HCoV-OC43, and HCoV-229E viral infections in cell culture. Our work reveals that the assembly dynamics of N condensates can be regulated by small molecules with therapeutic potential. Our approach allows for screening based on viral genome sequences alone and might enable rapid paths to drug discovery with value for confronting future pandemics.
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Affiliation(s)
- Rui Tong Quek
- Department of Systems Biology, Harvard
Medical School, Boston, Massachusetts 02115, United
States
- Wyss Institute for Biologically Inspired Engineering,
Harvard University, Boston, Massachusetts 02115,
United States
| | - Kierra S. Hardy
- Department of Systems Biology, Harvard
Medical School, Boston, Massachusetts 02115, United
States
- Wyss Institute for Biologically Inspired Engineering,
Harvard University, Boston, Massachusetts 02115,
United States
| | - Stephen G. Walker
- Drug Discovery Science and Technology,
AbbVie Inc., North Chicago, Illinois 60064, United
States
| | - Dan T. Nguyen
- Department of Systems Biology, Harvard
Medical School, Boston, Massachusetts 02115, United
States
- Wyss Institute for Biologically Inspired Engineering,
Harvard University, Boston, Massachusetts 02115,
United States
| | | | - Adrian Salic
- Department of Cell Biology, Harvard
Medical School, Boston, Massachusetts 02115, United
States
| | | | - Pamela A. Silver
- Department of Systems Biology, Harvard
Medical School, Boston, Massachusetts 02115, United
States
- Wyss Institute for Biologically Inspired Engineering,
Harvard University, Boston, Massachusetts 02115,
United States
| | - Timothy J. Mitchison
- Department of Systems Biology, Harvard
Medical School, Boston, Massachusetts 02115, United
States
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11
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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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12
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ATTCT and ATTCC repeat expansions in the ATXN10 gene affect disease penetrance of spinocerebellar ataxia type 10. HGG ADVANCES 2022; 3:100137. [PMID: 36092952 PMCID: PMC9460507 DOI: 10.1016/j.xhgg.2022.100137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 08/11/2022] [Indexed: 11/21/2022] Open
Abstract
Spinocerebellar ataxia type 10 (SCA10) is an autosomal-dominant disorder caused by an expanded pentanucleotide repeat in the ATXN10 gene. This repeat expansion, when fully penetrant, has a size of 850–4,500 repeats. It has been shown that the repeat composition can be a modifier of disease, e.g., seizures. Here, we describe a Mexican kindred in which we identified both pure (ATTCT)n and mixed (ATTCT)n-(ATTCC)n expansions in the same family. We used amplification-free targeted sequencing and optical genome mapping to decipher the composition of these repeat expansions. We found a considerable degree of mosaicism of the repeat expansion. This mosaicism was confirmed in skin fibroblasts from individuals with ATXN10 expansions with RNAScope in situ hybridization. All affected family members with the mixed ATXN10 repeat expansion showed typical clinical signs of spinocerebellar ataxia and epilepsy. In contrast, individuals with the pure ATXN10 expansion present with Parkinson's disease or are unaffected, even in individuals more than 20 years older than the average age at onset for SCA10. Our findings suggest that the pure (ATTCT)n expansion is non-pathogenic, while repeat interruptions, e.g., (ATTCC)n, are necessary to cause SCA10. This mechanism has been recently described for several other repeat expansions including SCA31 (BEAN1), SCA37 (DAB1), and three loci for benign adult familial myoclonic epilepsy BAFME (SAMD12, TNRC6A, RAPGEF2). Therefore, long-read sequencing and optical genome mapping of the entire genomic structure of repeat expansions are critical for clinical practice and genetic counseling, as variations in the repeat can affect disease penetrance, symptoms, and disease trajectory.
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13
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Cohen O, Ram Y, Hadany L, Geffen E, Gafny S. The effect of habitat and climatic on microsatellite diversity and allele length variation. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.893856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Microsatellite loci have been shown to vary according to environment. We studied allelic length variation and diversity in eight microsatellite loci along a sharp climatic and habitat gradient in Israel, using the eastern spadefoot toad (Pelobates syriacus) as our model system. We found a gradual increase in allele lengths from north to south. We used a distance-based redundancy analysis (dbRDA) to associate between allele length and habitat and climatic measures and found that geography and annual climate explained the significant variation in allele length. We also used additional measurements pertaining to demography, heterozygosity and allelic diversity to explore four different hypotheses that might explain the variations in allele length. Our results suggest that the changes we observed in allele lengths may not be purely random but could be influenced by the differential mutation rate and/or local environmental conditions operating at the different locations.
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14
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Kelley CP, Haerle MC, Wang ET. Negative autoregulation mitigates collateral RNase activity of repeat-targeting CRISPR-Cas13d in mammalian cells. Cell Rep 2022; 40:111226. [PMID: 35977479 PMCID: PMC9809062 DOI: 10.1016/j.celrep.2022.111226] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/29/2022] [Accepted: 07/26/2022] [Indexed: 01/05/2023] Open
Abstract
CRISPR-Cas13 RNA endonucleases show promise for programmable RNA knockdown. However, sequence-specific binding of Cas13 unleashes non-specific bystander RNA cleavage, or collateral activity, raising concerns for experiments and therapeutic applications. Although robust in cell-free and bacterial environments, collateral activity in mammalian cells remains disputed. We investigate Cas13d collateral activity in a therapeutic context for myotonic dystrophy type 1, caused by a transcribed CTG repeat expansion. We find that, when targeting CUGn RNA in mammalian cells, Cas13d depletes endogenous and transgenic RNAs, interferes with critical cellular processes, and activates stress response and apoptosis. Collateral effects also occur when targeting abundant endogenous transcripts. To minimize collateral activity for repeat-targeting approaches, we introduce GENO, an adeno-associated virus-compatible strategy that leverages guide RNA processing to control Cas13d expression. We argue that thorough assessment of collateral activity is necessary when applying Cas13 in mammalian cells and that GENO illustrates advantages of compact regulatory systems for Cas-based gene therapies.
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Affiliation(s)
- Chase P Kelley
- Department of Molecular Genetics & Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL 32608, USA; Genetics and Genomics Graduate Program, University of Florida, Gainesville, FL 32608, USA
| | - Maja C Haerle
- Department of Molecular Genetics & Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL 32608, USA
| | - Eric T Wang
- Department of Molecular Genetics & Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL 32608, USA; Myology Institute, University of Florida, Gainesville, FL 32608, USA.
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15
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Li M, Liu F, Hao X, Fan Y, Li J, Hu Z, Shi J, Fan L, Zhang S, Ma D, Guo M, Xu Y, Shi C. Rare KCND3 Loss-of-Function Mutation Associated With the SCA19/22. Front Mol Neurosci 2022; 15:919199. [PMID: 35813061 PMCID: PMC9261871 DOI: 10.3389/fnmol.2022.919199] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 05/19/2022] [Indexed: 12/15/2022] Open
Abstract
Spinocerebellar ataxia 19/22 (SCA19/22) is a rare neurodegenerative disorder caused by mutations of the KCND3 gene, which encodes the Kv4. 3 protein. Currently, only 22 KCND3 single-nucleotide mutation sites of SCA19/22 have been reported worldwide, and detailed pathogenesis remains unclear. In this study, Sanger sequencing was used to screen 115 probands of cerebellar ataxia families in 67 patients with sporadic cerebellar ataxia and 200 healthy people to identify KCND3 mutations. Mutant gene products showed pathogenicity damage, and the polarity was changed. Next, we established induced pluripotent stem cells (iPSCs) derived from SCA19/22 patients. Using a transcriptome sequencing technique, we found that protein processing in the endoplasmic reticulum was significantly enriched in SCA19/22-iPS-derived neurons and was closely related to endoplasmic reticulum stress (ERS) and apoptosis. In addition, Western blotting of the SCA19/22-iPS-derived neurons showed a reduction in Kv4.3; but, activation of transcription factor 4 (ATF4) and C/EBP homologous protein was increased. Therefore, the c.1130 C>T (p.T377M) mutation of the KCND3 gene may mediate misfold and aggregation of Kv4.3, which activates the ERS and further induces neuron apoptosis involved in SCA19/22.
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Affiliation(s)
- Mengjie Li
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Fen Liu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Xiaoyan Hao
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Yu Fan
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Jiadi Li
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Zhengwei Hu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Jingjing Shi
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Department of Cell Biology and Medical Genetics, Basic Medical College of Zhengzhou University, Zhengzhou, China
| | - Liyuan Fan
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Shuo Zhang
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, China
| | - Dongrui Ma
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Mengnan Guo
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Yuming Xu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Department of Cell Biology and Medical Genetics, Basic Medical College of Zhengzhou University, Zhengzhou, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Institute of Neuroscience, Zhengzhou University, Zhengzhou, China
- The Henan Medical Key Laboratory of Hereditary Neurodegenerative Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- The Key Laboratory of Cerebrovascular Diseases Prevention and Treatment, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Changhe Shi
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Henan Key Laboratory of Cerebrovascular Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- Institute of Neuroscience, Zhengzhou University, Zhengzhou, China
- The Henan Medical Key Laboratory of Hereditary Neurodegenerative Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- The Key Laboratory of Cerebrovascular Diseases Prevention and Treatment, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
- *Correspondence: Changhe Shi
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16
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Pozojevic J, von Holt BH, Westenberger A. Factors influencing reduced penetrance and variable expressivity in X-linked dystonia-parkinsonism. MED GENET-BERLIN 2022; 34:97-102. [PMID: 38835911 PMCID: PMC11007627 DOI: 10.1515/medgen-2022-2135] [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: 06/06/2024]
Abstract
X-linked dystonia-parkinsonism (XDP) is a neurodegenerative movement disorder that primarily affects adult Filipino men. It is caused by a founder retrotransposon insertion in TAF1 that contains a hexanucleotide repeat, the number of which differs among the patients and correlates with the age at disease onset (AAO) and other clinical parameters. A recent work has identified additional genetic modifiers of age-associated penetrance in XDP, bringing to light the DNA mismatch repair genes MSH3 and PMS2. Despite X-linked recessive inheritance, a minor subset of patients are female, manifesting the disease via various mechanisms such as homozygosity, imbalanced X-chromosome inactivation, or aneuploidy. Here, we summarize and discuss clinical and genetic aspects of XDP, with a focus on variable disease expressivity as a consequence of subtle genetic differences within a seemingly homogenous population of patients.
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Affiliation(s)
- Jelena Pozojevic
- Institute of Neurogenetics, University of Lübeck and University Hospital Schleswig-Holstein, BMF, Building 67; Ratzeburger Allee 160, 23538 Lübeck, Germany
- Institute of Human Genetics, University of Lübeck and University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Björn-Hergen von Holt
- Institute of Medical Biometry and Statistics, University of Lübeck and University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Ana Westenberger
- Institute of Neurogenetics, University of Lübeck and University Hospital Schleswig-Holstein, BMF, Building 67; Ratzeburger Allee 160, 23538 Lübeck, Germany
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17
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Liufu T, Zheng Y, Yu J, Yuan Y, Wang Z, Deng J, Hong D. The polyG diseases: a new disease entity. Acta Neuropathol Commun 2022; 10:79. [PMID: 35642014 PMCID: PMC9153130 DOI: 10.1186/s40478-022-01383-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/16/2022] [Indexed: 12/20/2022] Open
Abstract
Recently, inspired by the similar clinical and pathological features shared with fragile X-associated tremor/ataxia syndrome (FXTAS), abnormal expansion of CGG repeats in the 5' untranslated region has been found in neuronal intranuclear inclusion disease (NIID), oculopharyngeal myopathy with leukoencephalopathy (OPML), and oculopharyngodistal myopathy (OPDMs). Although the upstream open reading frame has not been elucidated in OPML and OPDMs, polyglycine (polyG) translated by expanded CGG repeats is reported to be as a primary pathogenesis in FXTAS and NIID. Collectively, these findings indicate a new disease entity, the polyG diseases. In this review, we state the common clinical manifestations, pathological features, mechanisms, and potential therapies in these diseases, and provide preliminary opinions about future research in polyG diseases.
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Affiliation(s)
- Tongling Liufu
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yilei Zheng
- Department of Neurology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Jiaxi Yu
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Jianwen Deng
- Department of Neurology, Peking University First Hospital, Beijing, China. .,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China.
| | - Daojun Hong
- Department of Neurology, The First Affiliated Hospital of Nanchang University, Nanchang, China. .,Department of Medical Genetics, The First Affiliated Hospital of Nanchang University, Nanchang, China.
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18
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Mechanistic and Therapeutic Insights into Ataxic Disorders with Pentanucleotide Expansions. Cells 2022; 11:cells11091567. [PMID: 35563872 PMCID: PMC9099484 DOI: 10.3390/cells11091567] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/02/2022] [Accepted: 05/05/2022] [Indexed: 02/01/2023] Open
Abstract
Pentanucleotide expansion diseases constitute a special class of neurodegeneration. The repeat expansions occur in non-coding regions, have likely arisen from Alu elements, and often result in autosomal dominant or recessive phenotypes with underlying cerebellar neuropathology. When transcribed (potentially bidirectionally), the expanded RNA forms complex secondary and tertiary structures that can give rise to RNA-mediated toxicity, including protein sequestration, pentapeptide synthesis, and mRNA dysregulation. Since several of these diseases have recently been discovered, our understanding of their pathological mechanisms is limited, and their therapeutic interventions underexplored. This review aims to highlight new in vitro and in vivo insights into these incurable diseases.
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19
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Johnson SL, Prifti MV, Sujkowski A, Libohova K, Blount JR, Hong L, Tsou WL, Todi SV. Drosophila as a Model of Unconventional Translation in Spinocerebellar Ataxia Type 3. Cells 2022; 11:cells11071223. [PMID: 35406787 PMCID: PMC8997593 DOI: 10.3390/cells11071223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 03/29/2022] [Accepted: 03/31/2022] [Indexed: 12/21/2022] Open
Abstract
RNA toxicity contributes to diseases caused by anomalous nucleotide repeat expansions. Recent work demonstrated RNA-based toxicity from repeat-associated, non-AUG-initiated translation (RAN translation). RAN translation occurs around long nucleotide repeats that form hairpin loops, allowing for translation initiation in the absence of a start codon that results in potentially toxic, poly-amino acid repeat-containing proteins. Discovered in Spinocerebellar Ataxia Type (SCA) 8, RAN translation has been documented in several repeat-expansion diseases, including in the CAG repeat-dependent polyglutamine (polyQ) disorders. The ATXN3 gene, which causes SCA3, also known as Machado–Joseph Disease (MJD), contains a CAG repeat that is expanded in disease. ATXN3 mRNA possesses features linked to RAN translation. In this paper, we examined the potential contribution of RAN translation to SCA3/MJD in Drosophila by using isogenic lines that contain homomeric or interrupted CAG repeats. We did not observe unconventional translation in fly neurons or glia. However, our investigations indicate differential toxicity from ATXN3 protein-encoding mRNA that contains pure versus interrupted CAG repeats. Additional work suggests that this difference may be due in part to toxicity from homomeric CAG mRNA. We conclude that Drosophila is not suitable to model RAN translation for SCA3/MJD, but offers clues into the potential pathogenesis stemming from CAG repeat-containing mRNA in this disorder.
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Affiliation(s)
- Sean L. Johnson
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
| | - Matthew V. Prifti
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
| | - Alyson Sujkowski
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
| | - Kozeta Libohova
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
| | - Jessica R. Blount
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
| | - Luke Hong
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
- Department of Neurology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Wei-Ling Tsou
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
| | - Sokol V. Todi
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
- Department of Neurology, Wayne State University School of Medicine, Detroit, MI 48201, USA
- Correspondence:
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20
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Abstract
The nematode Caenorhabditis elegans has shed light on many aspects of eukaryotic biology, including genetics, development, cell biology, and genomics. A major factor in the success of C. elegans as a model organism has been the availability, since the late 1990s, of an essentially gap-free and well-annotated nuclear genome sequence, divided among 6 chromosomes. In this review, we discuss the structure, function, and biology of C. elegans chromosomes and then provide a general perspective on chromosome biology in other diverse nematode species. We highlight malleable chromosome features including centromeres, telomeres, and repetitive elements, as well as the remarkable process of programmed DNA elimination (historically described as chromatin diminution) that induces loss of portions of the genome in somatic cells of a handful of nematode species. An exciting future prospect is that nematode species may enable experimental approaches to study chromosome features and to test models of chromosome evolution. In the long term, fundamental insights regarding how speciation is integrated with chromosome biology may be revealed.
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Affiliation(s)
- Peter M Carlton
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Richard E Davis
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Denver, CO 80045, USA.,RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Shawn Ahmed
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA.,Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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21
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Nedelsky NB, Taylor JP. Pathological phase transitions in ALS-FTD impair dynamic RNA-protein granules. RNA (NEW YORK, N.Y.) 2022; 28:97-113. [PMID: 34706979 PMCID: PMC8675280 DOI: 10.1261/rna.079001.121] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The genetics of human disease serves as a robust and unbiased source of insight into human biology, both revealing fundamental cellular processes and exposing the vulnerabilities associated with their dysfunction. Over the last decade, the genetics of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) have epitomized this concept, as studies of ALS-FTD-causing mutations have yielded fundamental discoveries regarding the role of biomolecular condensation in organizing cellular contents while implicating disturbances in condensate dynamics as central drivers of neurodegeneration. Here we review this genetic evidence, highlight its intersection with patient pathology, and discuss how studies in model systems have revealed a role for aberrant condensation in neuronal dysfunction and death. We detail how multiple, distinct types of disease-causing mutations promote pathological phase transitions that disturb the dynamics and function of ribonucleoprotein (RNP) granules. Dysfunction of RNP granules causes pleiotropic defects in RNA metabolism and can drive the evolution of these structures to end-stage pathological inclusions characteristic of ALS-FTD. We propose that aberrant phase transitions of these complex condensates in cells provide a parsimonious explanation for the widespread cellular abnormalities observed in ALS as well as certain histopathological features that characterize late-stage disease.
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Affiliation(s)
- Natalia B Nedelsky
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - J Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
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22
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Kumari A, Sedehizadeh S, Brook JD, Kozlowski P, Wojciechowska M. Differential fates of introns in gene expression due to global alternative splicing. Hum Genet 2021; 141:31-47. [PMID: 34907472 PMCID: PMC8758631 DOI: 10.1007/s00439-021-02409-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 12/02/2021] [Indexed: 02/06/2023]
Abstract
The discovery of introns over four decades ago revealed a new vision of genes and their interrupted arrangement. Throughout the years, it has appeared that introns play essential roles in the regulation of gene expression. Unique processing of excised introns through the formation of lariats suggests a widespread role for these molecules in the structure and function of cells. In addition to rapid destruction, these lariats may linger on in the nucleus or may even be exported to the cytoplasm, where they remain stable circular RNAs (circRNAs). Alternative splicing (AS) is a source of diversity in mature transcripts harboring retained introns (RI-mRNAs). Such RNAs may contain one or more entire retained intron(s) (RIs), but they may also have intron fragments resulting from sequential excision of smaller subfragments via recursive splicing (RS), which is characteristic of long introns. There are many potential fates of RI-mRNAs, including their downregulation via nuclear and cytoplasmic surveillance systems and the generation of new protein isoforms with potentially different functions. Various reports have linked the presence of such unprocessed transcripts in mammals to important roles in normal development and in disease-related conditions. In certain human neurological-neuromuscular disorders, including myotonic dystrophy type 2 (DM2), frontotemporal dementia/amyotrophic lateral sclerosis (FTD/ALS) and Duchenne muscular dystrophy (DMD), peculiar processing of long introns has been identified and is associated with their pathogenic effects. In this review, we discuss different mechanisms involved in the processing of introns during AS and the functions of these large sections of the genome in our biology.
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Affiliation(s)
- Anjani Kumari
- Queen's Medical Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Saam Sedehizadeh
- Queen's Medical Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - John David Brook
- Queen's Medical Centre, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Piotr Kozlowski
- Department of Molecular Genetics, Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznan, Poland
| | - Marzena Wojciechowska
- Department of Molecular Genetics, Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznan, Poland. .,Department of Rare Human Diseases, Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704, Poznan, Poland.
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23
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Pozojevic J, Cruz JN, Westenberger A. X-linked dystonia-parkinsonism: over and above a repeat disorder. MED GENET-BERLIN 2021; 33:319-324. [PMID: 38835428 PMCID: PMC11006257 DOI: 10.1515/medgen-2021-2105] [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: 04/29/2021] [Accepted: 11/24/2021] [Indexed: 06/06/2024]
Abstract
X-linked dystonia-parkinsonism (XDP) is an adult-onset neurodegenerative movement disorder, caused by a founder retrotransposon insertion in an intron of the TAF1 gene. This insertion contains a polymorphic hexanucleotide repeat (CCCTCT)n, the length of which inversely correlates with the age at disease onset (AAO) and other clinical parameters, aligning XDP with repeat expansion disorders. Nevertheless, many other pathogenic mechanisms are conceivably at play in XDP, indicating that in contrast to other repeat disorders, the (CCCTCT)n repeat may not be the actual (or only) disease cause. Here, we summarize and discuss genetic and molecular aspects of XDP, highlighting the role of the hexanucleotide repeat in age-related disease penetrance and expressivity.
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Affiliation(s)
- Jelena Pozojevic
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
- Institute of Human Genetics, University of Lübeck, Lübeck, Germany
| | - Joseph Neos Cruz
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
- Disease Molecular Biology and Epigenetics Laboratory, University of the Philippines Diliman, Quezon City, Philippines
| | - Ana Westenberger
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
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24
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Chen YG, Hur S. Cellular origins of dsRNA, their recognition and consequences. Nat Rev Mol Cell Biol 2021; 23:286-301. [PMID: 34815573 DOI: 10.1038/s41580-021-00430-1] [Citation(s) in RCA: 111] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2021] [Indexed: 01/02/2023]
Abstract
Double-stranded RNA (dsRNA) is associated with most viral infections - it either constitutes the viral genome (in the case of dsRNA viruses) or is generated in host cells during viral replication. Hence, nearly all organisms have the capability of recognizing dsRNA and mounting a response, the primary aim of which is to mitigate the potential infection. In vertebrates, a set of innate immune receptors for dsRNA induce a multitude of cell-intrinsic and cell-extrinsic immune responses upon dsRNA recognition. Notably, recent studies showed that vertebrate cells can accumulate self-derived dsRNAs or dsRNA-like species upon dysregulation of several cellular processes, activating the very same immune pathways as in infected cells. On the one hand, such aberrant immune activation in the absence of infection can lead to pathogenesis of immune disorders, such as Aicardi-Goutières syndrome. On the other hand, the same innate immune reaction can be induced in a controlled setting for a therapeutic benefit, as occurs in immunotherapies. In this Review, we describe mechanisms by which immunostimulatory dsRNAs are generated in mammalian cells, either by viruses or by the host cells, and how cells respond to them, with the focus on recent developments regarding the role of cellular dsRNAs in immune modulation.
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Affiliation(s)
- Y Grace Chen
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA.
| | - Sun Hur
- Harvard Medical School & Boston Children's Hospital, Boston, MA, USA.
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25
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Malik I, Kelley CP, Wang ET, Todd PK. Molecular mechanisms underlying nucleotide repeat expansion disorders. Nat Rev Mol Cell Biol 2021; 22:589-607. [PMID: 34140671 PMCID: PMC9612635 DOI: 10.1038/s41580-021-00382-6] [Citation(s) in RCA: 131] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2021] [Indexed: 02/05/2023]
Abstract
The human genome contains over one million short tandem repeats. Expansion of a subset of these repeat tracts underlies over fifty human disorders, including common genetic causes of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (C9orf72), polyglutamine-associated ataxias and Huntington disease, myotonic dystrophy, and intellectual disability disorders such as Fragile X syndrome. In this Review, we discuss the four major mechanisms by which expansion of short tandem repeats causes disease: loss of function through transcription repression, RNA-mediated gain of function through gelation and sequestration of RNA-binding proteins, gain of function of canonically translated repeat-harbouring proteins, and repeat-associated non-AUG translation of toxic repeat peptides. Somatic repeat instability amplifies these mechanisms and influences both disease age of onset and tissue specificity of pathogenic features. We focus on the crosstalk between these disease mechanisms, and argue that they often synergize to drive pathogenesis. We also discuss the emerging native functions of repeat elements and how their dynamics might contribute to disease at a larger scale than currently appreciated. Lastly, we propose that lynchpins tying these disease mechanisms and native functions together offer promising therapeutic targets with potential shared applications across this class of human disorders.
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Affiliation(s)
- Indranil Malik
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Chase P Kelley
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA
- Genetics and Genomics Graduate Program, University of Florida, Gainesville, FL, USA
| | - Eric T Wang
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, Gainesville, FL, USA.
| | - Peter 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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26
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Borbolla-Jiménez FV, Del Prado-Audelo ML, Cisneros B, Caballero-Florán IH, Leyva-Gómez G, Magaña JJ. New Perspectives of Gene Therapy on Polyglutamine Spinocerebellar Ataxias: From Molecular Targets to Novel Nanovectors. Pharmaceutics 2021; 13:1018. [PMID: 34371710 PMCID: PMC8309146 DOI: 10.3390/pharmaceutics13071018] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 01/03/2023] Open
Abstract
Seven of the most frequent spinocerebellar ataxias (SCAs) are caused by a pathological expansion of a cytosine, adenine and guanine (CAG) trinucleotide repeat located in exonic regions of unrelated genes, which in turn leads to the synthesis of polyglutamine (polyQ) proteins. PolyQ proteins are prone to aggregate and form intracellular inclusions, which alter diverse cellular pathways, including transcriptional regulation, protein clearance, calcium homeostasis and apoptosis, ultimately leading to neurodegeneration. At present, treatment for SCAs is limited to symptomatic intervention, and there is no therapeutic approach to prevent or reverse disease progression. This review provides a compilation of the experimental advances obtained in cell-based and animal models toward the development of gene therapy strategies against polyQ SCAs, providing a discussion of their potential application in clinical trials. In the second part, we describe the promising potential of nanotechnology developments to treat polyQ SCA diseases. We describe, in detail, how the design of nanoparticle (NP) systems with different physicochemical and functionalization characteristics has been approached, in order to determine their ability to evade the immune system response and to enhance brain delivery of molecular tools. In the final part of this review, the imminent application of NP-based strategies in clinical trials for the treatment of polyQ SCA diseases is discussed.
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Affiliation(s)
- Fabiola V. Borbolla-Jiménez
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación-Luis Guillermo Ibarra Ibarra, Ciudad de México 14389, Mexico;
- Programa de Ciencias Biomédicas, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - María Luisa Del Prado-Audelo
- Departamento de Bioingeniería, Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey Campus Ciudad de México, Ciudad de México 14380, Mexico;
| | - Bulmaro Cisneros
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Ciudad de México 07360, Mexico;
| | - Isaac H. Caballero-Florán
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico;
- Departamento de Farmacia, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Ciudad de México 07360, Mexico
| | - Gerardo Leyva-Gómez
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico;
| | - Jonathan J. Magaña
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación-Luis Guillermo Ibarra Ibarra, Ciudad de México 14389, Mexico;
- Departamento de Bioingeniería, Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey Campus Ciudad de México, Ciudad de México 14380, Mexico;
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27
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Zhang N, Bewick B, Schultz J, Tiwari A, Krencik R, Zhang A, Adachi K, Xia G, Yun K, Sarkar P, Ashizawa T. DNAzyme Cleavage of CAG Repeat RNA in Polyglutamine Diseases. Neurotherapeutics 2021; 18:1710-1728. [PMID: 34160773 PMCID: PMC8609077 DOI: 10.1007/s13311-021-01075-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2021] [Indexed: 02/05/2023] Open
Abstract
CAG repeat expansion is the genetic cause of nine incurable polyglutamine (polyQ) diseases with neurodegenerative features. Silencing repeat RNA holds great therapeutic value. Here, we developed a repeat-based RNA-cleaving DNAzyme that catalyzes the destruction of expanded CAG repeat RNA of six polyQ diseases with high potency. DNAzyme preferentially cleaved the expanded allele in spinocerebellar ataxia type 1 (SCA1) cells. While cleavage was non-allele-specific for spinocerebellar ataxia type 3 (SCA3) cells, treatment of DNAzyme leads to improved cell viability without affecting mitochondrial metabolism or p62-dependent aggresome formation. DNAzyme appears to be stable in mouse brain for at least 1 month, and an intermediate dosage of DNAzyme in a SCA3 mouse model leads to a significant reduction of high molecular weight ATXN3 proteins. Our data suggest that DNAzyme is an effective RNA silencing molecule for potential treatment of multiple polyQ diseases.
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Affiliation(s)
- Nan Zhang
- Department of Neurology, Neuroscience Program, Houston Methodist Research Institute, Houston, TX USA
| | - Brittani Bewick
- Department of Neurology, Neuroscience Program, Houston Methodist Research Institute, Houston, TX USA
| | - Jason Schultz
- Department of Neurology, Neuroscience Program, Houston Methodist Research Institute, Houston, TX USA
| | - Anjana Tiwari
- Department of Neurology, Neuroscience Program, Houston Methodist Research Institute, Houston, TX USA
| | - Robert Krencik
- Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX USA
| | - Aijun Zhang
- Center for Bioenergetics, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX USA
| | - Kaho Adachi
- Department of Molecular and Cell Biology, UC-Berkeley, Berkeley, CA USA
| | - Guangbin Xia
- Indiana University School of Medicine-Fort Wayne, Fort Wayne, IN USA
| | - Kyuson Yun
- Department of Neurology, Neuroscience Program, Houston Methodist Research Institute, Houston, TX USA
| | - Partha Sarkar
- Department of Neurology and Department of Neuroscience, Cell Biology and Anatomy, UTMB Health, Galveston, TX USA
| | - Tetsuo Ashizawa
- Department of Neurology, Neuroscience Program, Houston Methodist Research Institute, Houston, TX USA
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28
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Razin SV, Gavrilov AA. Non-coding RNAs in chromatin folding and nuclear organization. Cell Mol Life Sci 2021; 78:5489-5504. [PMID: 34117518 PMCID: PMC11072467 DOI: 10.1007/s00018-021-03876-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/24/2021] [Accepted: 06/05/2021] [Indexed: 12/19/2022]
Abstract
One of the most intriguing questions facing modern biology concerns how the genome directs the construction of cells, tissues, and whole organisms. It is tempting to suggest that the part of the genome that does not encode proteins contains architectural plans. We are still far from understanding how these plans work at the level of building tissues and the body as a whole. However, the results of recent studies demonstrate that at the cellular level, special non-coding RNAs serve as scaffolds for the construction of various intracellular structures. The term "architectural RNAs" was proposed to designate this subset of non-coding RNAs. In this review, we discuss the role of architectural RNAs in the construction of the cell nucleus and maintenance of the three-dimensional organization of the genome.
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Affiliation(s)
- Sergey V Razin
- Institute of Gene Biology, Russian Academy of Sciences, 119334, Moscow, Russia.
- Faculty of Biology, M. V. Lomonosov Moscow State University, 119234, Moscow, Russia.
| | - Alexey A Gavrilov
- Institute of Gene Biology, Russian Academy of Sciences, 119334, Moscow, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 119334, Moscow, Russia
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29
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Ishiguro T, Nagai Y, Ishikawa K. Insight Into Spinocerebellar Ataxia Type 31 (SCA31) From Drosophila Model. Front Neurosci 2021; 15:648133. [PMID: 34113230 PMCID: PMC8185138 DOI: 10.3389/fnins.2021.648133] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/31/2021] [Indexed: 11/13/2022] Open
Abstract
Spinocerebellar ataxia type 31 (SCA31) is a progressive neurodegenerative disease characterized by degeneration of Purkinje cells in the cerebellum. Its genetic cause is a 2.5- to 3.8-kb-long complex pentanucleotide repeat insertion containing (TGGAA)n, (TAGAA)n, (TAAAA)n, and (TAAAATAGAA)n located in an intron shared by two different genes: brain expressed associated with NEDD4-1 (BEAN1) and thymidine kinase 2 (TK2). Among these repeat sequences, (TGGAA)n repeat was the only sequence segregating with SCA31, which strongly suggests its pathogenicity. In SCA31 patient brains, the mutant BEAN1 transcript containing expanded UGGAA repeats (UGGAAexp) was found to form abnormal RNA structures called RNA foci in cerebellar Purkinje cell nuclei. In addition, the deposition of pentapeptide repeat (PPR) proteins, poly(Trp-Asn-Gly-Met-Glu), translated from UGGAAexp RNA, was detected in the cytoplasm of Purkinje cells. To uncover the pathogenesis of UGGAAexp in SCA31, we generated Drosophila models of SCA31 expressing UGGAAexp RNA. The toxicity of UGGAAexp depended on its length and expression level, which was accompanied by the accumulation of RNA foci and translation of repeat-associated PPR proteins in Drosophila, consistent with the observation in SCA31 patient brains. We also revealed that TDP-43, FUS, and hnRNPA2B1, motor neuron disease–linked RNA-binding proteins bound to UGGAAexp RNA, act as RNA chaperones to regulate the formation of RNA foci and repeat-associated translation. Further research on the role of RNA-binding proteins as RNA chaperones may also provide a novel therapeutic strategy for other microsatellite repeat expansion diseases besides SCA31.
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Affiliation(s)
- Taro Ishiguro
- Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Bunkyo City, Japan
| | - Yoshitaka Nagai
- Department of Neurotherapeutics, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kinya Ishikawa
- Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Bunkyo City, Japan.,Department of Personalized Genomic Medicine for Health, Graduate School, Tokyo Medical and Dental University, Bunkyo City, Japan
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30
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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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31
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Li D, McIntosh CS, Mastaglia FL, Wilton SD, Aung-Htut MT. Neurodegenerative diseases: a hotbed for splicing defects and the potential therapies. Transl Neurodegener 2021; 10:16. [PMID: 34016162 PMCID: PMC8136212 DOI: 10.1186/s40035-021-00240-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 04/23/2021] [Indexed: 12/14/2022] Open
Abstract
Precursor messenger RNA (pre-mRNA) splicing is a fundamental step in eukaryotic gene expression that systematically removes non-coding regions (introns) and ligates coding regions (exons) into a continuous message (mature mRNA). This process is highly regulated and can be highly flexible through a process known as alternative splicing, which allows for several transcripts to arise from a single gene, thereby greatly increasing genetic plasticity and the diversity of proteome. Alternative splicing is particularly prevalent in neuronal cells, where the splicing patterns are continuously changing to maintain cellular homeostasis and promote neurogenesis, migration and synaptic function. The continuous changes in splicing patterns and a high demand on many cis- and trans-splicing factors contribute to the susceptibility of neuronal tissues to splicing defects. The resultant neurodegenerative diseases are a large group of disorders defined by a gradual loss of neurons and a progressive impairment in neuronal function. Several of the most common neurodegenerative diseases involve some form of splicing defect(s), such as Alzheimer's disease, Parkinson's disease and spinal muscular atrophy. Our growing understanding of RNA splicing has led to the explosion of research in the field of splice-switching antisense oligonucleotide therapeutics. Here we review our current understanding of the effects alternative splicing has on neuronal differentiation, neuronal migration, synaptic maturation and regulation, as well as the impact on neurodegenerative diseases. We will also review the current landscape of splice-switching antisense oligonucleotides as a therapeutic strategy for a number of common neurodegenerative disorders.
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Affiliation(s)
- Dunhui Li
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, Western Australia, Australia.,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, Western Australia, Australia
| | - Craig Stewart McIntosh
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, Western Australia, Australia.,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, Western Australia, Australia
| | - Frank Louis Mastaglia
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, Western Australia, Australia.,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, Western Australia, Australia
| | - Steve Donald Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, Western Australia, Australia.,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, Western Australia, Australia
| | - May Thandar Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, Western Australia, Australia. .,Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Perth, Western Australia, Australia.
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32
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Connecting the "dots": RNP granule network in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119058. [PMID: 33989700 DOI: 10.1016/j.bbamcr.2021.119058] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 05/01/2021] [Accepted: 05/07/2021] [Indexed: 12/26/2022]
Abstract
All cells contain ribonucleoprotein (RNP) granules - large membraneless structures composed of RNA and proteins. Recent breakthroughs in RNP granule research have brought a new appreciation of their crucial role in organising virtually all cellular processes. Cells widely exploit the flexible, dynamic nature of RNP granules to adapt to a variety of functional states and the ever-changing environment. Constant exchange of molecules between the different RNP granules connects them into a network. This network controls basal cellular activities and is remodelled to enable efficient stress response. Alterations in RNP granule structure and regulation have been found to lead to fatal human diseases. The interconnectedness of RNP granules suggests that the RNP granule network as a whole becomes affected in disease states such as a representative neurodegenerative disease amyotrophic lateral sclerosis (ALS). In this review, we summarize available evidence on the communication between different RNP granules and on the RNP granule network disruption as a primary ALS pathomechanism.
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33
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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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34
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Ajjugal Y, Kolimi N, Rathinavelan T. Secondary structural choice of DNA and RNA associated with CGG/CCG trinucleotide repeat expansion rationalizes the RNA misprocessing in FXTAS. Sci Rep 2021; 11:8163. [PMID: 33854084 PMCID: PMC8046799 DOI: 10.1038/s41598-021-87097-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 03/22/2021] [Indexed: 11/09/2022] Open
Abstract
CGG tandem repeat expansion in the 5'-untranslated region of the fragile X mental retardation-1 (FMR1) gene leads to unusual nucleic acid conformations, hence causing genetic instabilities. We show that the number of G…G (in CGG repeat) or C…C (in CCG repeat) mismatches (other than A…T, T…A, C…G and G…C canonical base pairs) dictates the secondary structural choice of the sense and antisense strands of the FMR1 gene and their corresponding transcripts in fragile X-associated tremor/ataxia syndrome (FXTAS). The circular dichroism (CD) spectra and electrophoretic mobility shift assay (EMSA) reveal that CGG DNA (sense strand of the FMR1 gene) and its transcript favor a quadruplex structure. CD, EMSA and molecular dynamics (MD) simulations also show that more than four C…C mismatches cannot be accommodated in the RNA duplex consisting of the CCG repeat (antisense transcript); instead, it favors an i-motif conformational intermediate. Such a preference for unusual secondary structures provides a convincing justification for the RNA foci formation due to the sequestration of RNA-binding proteins to the bidirectional transcripts and the repeat-associated non-AUG translation that are observed in FXTAS. The results presented here also suggest that small molecule modulators that can destabilize FMR1 CGG DNA and RNA quadruplex structures could be promising candidates for treating FXTAS.
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Affiliation(s)
- Yogeeshwar Ajjugal
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana State, 502285, India
| | - Narendar Kolimi
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana State, 502285, India
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35
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Deng J, Zhou B, Yu J, Han X, Fu J, Li X, Xie X, Zhu M, Zheng Y, Guo X, Li P, Wang Q, Liu J, Zhang W, Yuan Y, Yao S, Wang Z, Hong D. Genetic origin of sporadic cases and RNA toxicity in neuronal intranuclear inclusion disease. J Med Genet 2021; 59:462-469. [PMID: 33766934 DOI: 10.1136/jmedgenet-2020-107649] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 02/10/2021] [Accepted: 03/10/2021] [Indexed: 11/04/2022]
Abstract
BACKGROUND GGC repeat expansion in NOTCH2NLC has been recently linked to neuronal intranuclear inclusion disease (NIID) via unknown disease mechanisms. Herein, we explore the genetic origin of the sporadic cases and toxic RNA gain-of-function mechanism in NIID. METHODS Multiple genetic screenings were performed on NIID individuals and their available family members. Methylation status of blood DNA, NOTCH2NLC mRNA level from muscle biopsies and RNA foci from skin biopsies of NIID individuals or asymptomatic carriers were evaluated and compared. RESULTS In two sporadic NIID families, we identified two clinically and pathologically asymptomatic fathers carrying large GGC repeat expansion, above 300 repeats, with offspring repeat numbers of 172 and 148, respectively. Further evaluation revealed that the GGC repeat numbers in the sperm from two asymptomatic fathers were only 63 and 98, respectively. The CpG island in NOTCH2NLC of the asymptomatic carriers was hypermethylated, and accordingly, the NOTCH2NLC mRNA levels were decreased in the asymptomatic fathers. GGC repeat expansion RNA formed RNA foci and sequestered RNA binding proteins into p62 positive intranuclear inclusions in NIID individuals but not in the control or asymptomatic carrier. CONCLUSION Our study suggested the GGC repeat expansion in NOTCH2NLC might have a disease-causing number ranging from ~41 to ~300 repeats. The contraction of GGC repeat expansion in sperm could be a possible mechanism for the paternal-biased origin in some sporadic or recessive inherited NIID individuals. The toxic RNA gain-of-function mechanism was identified to be involved in the pathogenicity of this disease.
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Affiliation(s)
- Jianwen Deng
- Department of Neurology, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Binbin Zhou
- Department of Neurology, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Jiaxi Yu
- Department of Neurology, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Xiaochen Han
- Department of Neurology, Sixth Medical Center of PLA General Hospital, Beijing, China
| | - Jianhui Fu
- Department of Neurology, Huashan Hospital Fudan University, Shanghai, China
| | - Xiaobin Li
- Department of Neurology, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Xufang Xie
- Department of Neurology, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Min Zhu
- Department of Neurology, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Yilei Zheng
- Department of Neurology, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Xueyu Guo
- Grandomics Biosciences, Beijing, China
| | - Pidong Li
- Grandomics Biosciences, Beijing, China
| | - Qingqing Wang
- Department of Neurology, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Jing Liu
- Department of Neurology, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Beijing, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Sheng Yao
- Department of Neurology, Sixth Medical Center of PLA General Hospital, Beijing, China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, Beijing, China .,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, China
| | - Daojun Hong
- Department of Neurology, First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China .,Department of Neurology, Peking University People's Hospital, Beijing, China
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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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37
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Pan S, Li X, Li L, Lin H, Wang D, Zhang X, Zhao X, Ye J, Huang Z, Lin Y, Duan Y, Ma R, Gao L, Wang C, Wang Y. Comprehensive genetic, clinical and electrophysiological studies of familial cortical myoclonic tremor with epilepsy 1 highlight the role of gene configurations. Seizure 2021; 87:69-74. [PMID: 33721773 DOI: 10.1016/j.seizure.2021.02.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 02/19/2021] [Accepted: 02/21/2021] [Indexed: 01/17/2023] Open
Abstract
OBJECTIVES Two configurations of TTTTA/TTTCA expansion in SAMD12 have been identified in familial cortical myoclonic tremor with epilepsy type 1 (FCMTE1). This study investigated the clinical and neurophysiological features of FCMTE1 and their association with TTTTA/TTTCA expansion patterns. METHODS In total, 76 patients from 20 Chinese pedigrees were enrolled. Genetic (TTTTA/TTTCA configuration), clinical (e.g., onset, medication, prognosis, and anticipation) and neurophysiological examination (e.g., electroencephalogram and magnetoencephalography) data were evaluated, and associations between these parameters were analyzed. RESULTS All patients carried the TTTTA/TTTCA expansion mutation, 19 displayed the (TTTTA)exp(TTTCA)exp (type I) configuration and 1 displayed the (TTTTA)exp (TTTCA)exp(TTTTA)exp (type II) configuration. All patients manifested as progressive tremor, but symptoms of patients carrying type II expansion were more severe. The onset of tremor but not generalized tonic and clonic seizures displayed clinical anticipation between generations of 7 pedigrees, but the pedigree carrying the type II mutation did not show anticipation. Nanopore sequencing showed that the repeats expanded during maternal/offspring transmission (pedigree #7) but shrank during paternal/offspring transmission (pedigree #9). Magnetoencephalographic dipoles were localized in the right frontal lobe near the central sulcus in 4 patients carrying the type I mutation and on the left side in one patient carrying the type II mutation. SIGNIFICANCE We confirmed the causative roles played by TTTTA/TTTCA repeat expansion in the SAMD12 gene in FCTME1. Both the length and the configuration of the repeats contribute to the clinical and neurophysiological characteristics of the disease.
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Affiliation(s)
- Sipei Pan
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China
| | - Xuying Li
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Liping Li
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Hua Lin
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Dequan Wang
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Xiating Zhang
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Xin Zhao
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Jing Ye
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China
| | - Zhaoyang Huang
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China
| | - Yicong Lin
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China
| | - Yiran Duan
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China
| | - Rui Ma
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China
| | - Lehong Gao
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China.
| | - Chaodong Wang
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; National Clinical Research Center for Geriatric Diseases, Beijing, 100053, China.
| | - Yuping Wang
- Department of Neurology, Xuanwu Hosptial, Captial Medical University, Beijing, 100053, China; Beijing Key Laboratory of Neuromodulation, Beijing, 100053, China.
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38
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Latorre A, Rocchi L, Magrinelli F, Mulroy E, Berardelli A, Rothwell JC, Bhatia KP. Unravelling the enigma of cortical tremor and other forms of cortical myoclonus. Brain 2021; 143:2653-2663. [PMID: 32417917 DOI: 10.1093/brain/awaa129] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 02/11/2020] [Accepted: 02/27/2020] [Indexed: 12/21/2022] Open
Abstract
Cortical tremor is a fine rhythmic oscillation involving distal upper limbs, linked to increased sensorimotor cortex excitability, as seen in cortical myoclonus. Cortical tremor is the hallmark feature of autosomal dominant familial cortical myoclonic tremor and epilepsy (FCMTE), a syndrome not yet officially recognized and characterized by clinical and genetic heterogeneity. Non-coding repeat expansions in different genes have been recently recognized to play an essential role in its pathogenesis. Cortical tremor is considered a rhythmic variant of cortical myoclonus and is part of the 'spectrum of cortical myoclonus', i.e. a wide range of clinical motor phenomena, from reflex myoclonus to myoclonic epilepsy, caused by abnormal sensorimotor cortical discharges. The aim of this update is to provide a detailed analysis of the mechanisms defining cortical tremor, as seen in FCMTE. After reviewing the clinical and genetic features of FCMTE, we discuss the possible mechanisms generating the distinct elements of the cortical myoclonus spectrum, and how cortical tremor fits into it. We propose that the spectrum is due to the evolution from a spatially limited focus of excitability to recruitment of more complex mechanisms capable of sustaining repetitive activity, overcoming inhibitory mechanisms that restrict excitatory bursts, and engaging wide areas of cortex. Finally, we provide evidence for a possible common denominator of the elements of the spectrum, i.e. the cerebellum, and discuss its role in FCMTE, according to recent genetic findings.
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Affiliation(s)
- Anna Latorre
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK
- Department of Human Neurosciences, Sapienza University of Rome, Italy
| | - Lorenzo Rocchi
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK
| | - Francesca Magrinelli
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Eoin Mulroy
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK
| | - Alfredo Berardelli
- Department of Human Neurosciences, Sapienza University of Rome, Italy
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, Pozzilli, IS, Italy
| | - John C Rothwell
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK
| | - Kailash P Bhatia
- Department of Clinical and Movement Neurosciences, Queen Square Institute of Neurology, University College London, London, UK
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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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40
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Zhang N, Bewick B, Xia G, Furling D, Ashizawa T. A CRISPR-Cas13a Based Strategy That Tracks and Degrades Toxic RNA in Myotonic Dystrophy Type 1. Front Genet 2020; 11:594576. [PMID: 33362853 PMCID: PMC7758406 DOI: 10.3389/fgene.2020.594576] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 11/23/2020] [Indexed: 12/18/2022] Open
Abstract
Cas13a, an effector of type VI CRISPR-Cas systems, is an RNA guided RNase with multiplexing and therapeutic potential. This study employs the Leptotrichia shahii (Lsh) Cas13a and a repeat-based CRISPR RNA (crRNA) to track and eliminate toxic RNA aggregates in myotonic dystrophy type 1 (DM1) – a neuromuscular disease caused by CTG expansion in the DMPK gene. We demonstrate that LshCas13a cleaves CUG repeat RNA in biochemical assays and reduces toxic RNA load in patient-derived myoblasts. As a result, LshCas13a reverses the characteristic adult-to-embryonic missplicing events in several key genes that contribute to DM1 phenotype. The deactivated LshCas13a can further be repurposed to track RNA-rich organelles within cells. Our data highlights the reprogrammability of LshCas13a and the possible use of Cas13a to target expanded repeat sequences in microsatellite expansion diseases.
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Affiliation(s)
- Nan Zhang
- Department of Neurology, Houston Methodist Research Institute, Houston, TX, United States
| | - Brittani Bewick
- Department of Neurology, Houston Methodist Research Institute, Houston, TX, United States
| | - Guangbin Xia
- Indiana University School of Medicine, Fort Wayne, IN, United States
| | - Denis Furling
- Institut National de la Sante et de la Recherche Medicale (INSERM), Centre de Recherche en Myologie (CRM), Association Institut de Myologie, Sorbonne Université, Paris, France
| | - Tetsuo Ashizawa
- Department of Neurology, Houston Methodist Research Institute, Houston, TX, United States
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41
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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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42
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McEachin ZT, Parameswaran J, Raj N, Bassell GJ, Jiang J. RNA-mediated toxicity in C9orf72 ALS and FTD. Neurobiol Dis 2020; 145:105055. [PMID: 32829028 DOI: 10.1016/j.nbd.2020.105055] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/27/2020] [Accepted: 08/18/2020] [Indexed: 12/13/2022] Open
Abstract
A GGGGCC hexanucleotide repeat expansion in the first intron of C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Compelling evidence suggests that gain of toxicity from the bidirectionally transcribed repeat expanded RNAs plays a central role in disease pathogenesis. Two potential mechanisms have been proposed including RNA-mediated toxicity and/or the production of toxic dipeptide repeat proteins. In this review, we focus on the role of RNA mediated toxicity in ALS/FTD caused by the C9orf72 mutation and discuss arguments for and against this mechanism. In addition, we summarize how G4C2 repeat RNAs can elicit toxicity and potential therapeutic strategies to mitigate RNA-mediated toxicity.
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Affiliation(s)
- Zachary T McEachin
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA.
| | | | - Nisha Raj
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA; Department of Neurology, Emory University, Atlanta, GA 30322, USA
| | - Jie Jiang
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA.
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Familial cortical myoclonic tremor with epilepsy: TTTCA/TTTTA repeat expansions and expanding phenotype in two Chinese families. Brain Res 2020; 1737:146796. [PMID: 32194077 DOI: 10.1016/j.brainres.2020.146796] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 03/04/2020] [Accepted: 03/14/2020] [Indexed: 02/08/2023]
Abstract
Recently, expanded intronic TTTCA and TTTTA repeat in SAMD12 were identified in families with familial cortical myoclonic tremor with epilepsy (FCMTE). We conducted to this study to clarify the genetic etiology and to describe the clinical, neurophysiologic, and imaging features in two unrelated Chinese families with FCMTE. In this study, we performed the RP-PCR and long-range PCR analysis to examine and verifyTTTCA and TTTTA expansions in five affected members whose severities of cortical tremor, neuropsychology and MRI were also evaluated. Reliable clinical information was collected from another two affected members. Our results revealed that expansions of intronic TTTCA and TTTTA repeats in SAMD12 were both identified in all five affected subjects. All seven affected living patients had cortical tremor with a median age at onset of 16.4 years (range, 10-22 years). Convulsions occurred in 5 of 7 with a median age at onset of 32.4 years (range, 10-42 years). Among five patients evaluated for cortical tremor severity and psychiatric comorbidity, two patients had severe cortical tremor, anxiety and depression. Abnormal brain MRI findings including the possible existence of demyelination, severe atrophy of the cerebral hemisphere and abnormal bilateral symmetrical signals in the globus pallidus were observed in three patients, respectively. These results further expanded the known genotype in two Chinese families affected with FCMTE. Border clinical spectrum needs to be confirmed in future studies from additional FCMTE families genetically diagnosed.
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Yamazaki T, Nakagawa S, Hirose T. Architectural RNAs for Membraneless Nuclear Body Formation. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2020; 84:227-237. [PMID: 32019862 DOI: 10.1101/sqb.2019.84.039404] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Long noncoding RNAs (lncRNAs) are fundamental regulators of various cellular processes. A subset of lncRNAs, termed architectural RNAs (arcRNAs), function in the formation and maintenance of phase-separated membraneless organelles in multiple eukaryotic species. These membraneless organelles represent an important type of compartmentalization in the crowded cellular environment and have several distinct features. The NEAT1_2 lncRNA is a well-characterized arcRNA that functions as an essential scaffold of paraspeckle nuclear bodies. Here, we describe the biogenesis of paraspeckles on arcRNAs through phase separation, focusing on the specific functions of multiple NEAT1_2 RNA domains and their partner RNA-binding proteins. Finally, we present an updated model of paraspeckle formation and discuss future perspectives of research into arcRNA-instructed architectures of phase-separated nuclear bodies.
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Affiliation(s)
- Tomohiro Yamazaki
- Institute for Genetic Medicine, Hokkaido University, Sapporo, 060-0815 Japan
| | - Shinichi Nakagawa
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, 060-0812 Japan
| | - Tetsuro Hirose
- Institute for Genetic Medicine, Hokkaido University, Sapporo, 060-0815 Japan
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45
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Bridging biophysics and neurology: aberrant phase transitions in neurodegenerative disease. Nat Rev Neurol 2020; 15:272-286. [PMID: 30890779 DOI: 10.1038/s41582-019-0157-5] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Biomolecular condensation arising through phase transitions has emerged as an essential organizational strategy that governs many aspects of cell biology. In particular, the role of phase transitions in the assembly of large, complex ribonucleoprotein (RNP) granules has become appreciated as an important regulator of RNA metabolism. In parallel, genetic, histopathological and cell and molecular studies have provided evidence that disturbance of phase transitions is an important driver of neurological diseases, notably amyotrophic lateral sclerosis (ALS), but most likely also other diseases. Indeed, our growing knowledge of the biophysics underlying biological phase transitions suggests that this process offers a unifying mechanism to explain the numerous and diverse disturbances in RNA metabolism that have been observed in ALS and some related diseases - specifically, that these diseases are driven by disturbances in the material properties of RNP granules. Here, we review the evidence for this hypothesis, emphasizing the reciprocal roles in which disease-related protein and disease-related RNA can lead to disturbances in the material properties of RNP granules and consequent pathogenesis. Additionally, we review evidence that implicates aberrant phase transitions as a contributing factor to a larger set of neurodegenerative diseases, including frontotemporal dementia, certain repeat expansion diseases and Alzheimer disease.
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46
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Shotwell CR, Cleary JD, Berglund JA. The potential of engineered eukaryotic RNA-binding proteins as molecular tools and therapeutics. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 11:e1573. [PMID: 31680457 DOI: 10.1002/wrna.1573] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/21/2019] [Accepted: 10/08/2019] [Indexed: 02/06/2023]
Abstract
Eukaroytic RNA-binding proteins (RBPs) recognize and process RNAs through recognition of their sequence motifs via RNA-binding domains (RBDs). RBPs usually consist of one or more RBDs and can include additional functional domains that modify or cleave RNA. Engineered RBPs have been used to answer basic biology questions, control gene expression, locate viral RNA in vivo, as well as many other tasks. Given the growing number of diseases associated with RNA and RBPs, engineered RBPs also have the potential to serve as therapeutics. This review provides an in depth description of recent advances in engineered RBPs and discusses opportunities and challenges in the field. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Methods > RNA Nanotechnology RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Carl R Shotwell
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida
| | - John D Cleary
- RNA Institute, University at Albany, Albany, New York
| | - J Andrew Berglund
- Department of Biological Sciences and RNA Institute, University at Albany, Albany, New York
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47
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Gottesfeld JM. Molecular Mechanisms and Therapeutics for the GAA·TTC Expansion Disease Friedreich Ataxia. Neurotherapeutics 2019; 16:1032-1049. [PMID: 31317428 PMCID: PMC6985418 DOI: 10.1007/s13311-019-00764-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Friedreich ataxia (FRDA), the most common inherited ataxia, is caused by transcriptional silencing of the nuclear FXN gene, encoding the essential mitochondrial protein frataxin. Currently, there is no approved therapy for this fatal disorder. Gene silencing in FRDA is due to hyperexpansion of the triplet repeat sequence GAA·TTC in the first intron of the FXN gene, which results in chromatin histone modifications consistent with heterochromatin formation. Frataxin is involved in mitochondrial iron homeostasis and the assembly and transfer of iron-sulfur clusters to various mitochondrial enzymes and components of the electron transport chain. Frataxin insufficiency leads to progressive spinocerebellar neurodegeneration, causing symptoms of gait and limb ataxia, slurred speech, muscle weakness, sensory loss, and cardiomyopathy in many patients, resulting in death in early adulthood. Numerous approaches are being taken to find a treatment for FRDA, including excision or correction of the repeats by genome engineering methods, gene activation with small molecules or artificial transcription factors, delivery of frataxin to affected cells by protein replacement therapy, gene therapy, or small molecules to increase frataxin protein levels, and therapies aimed at countering the cellular consequences of reduced frataxin. This review will summarize the mechanisms involved in repeat-mediated gene silencing and recent efforts aimed at development of therapeutics.
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Affiliation(s)
- Joel M Gottesfeld
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, 92037, USA.
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48
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Cen Z, Chen Y, Yang D, Zhu Q, Chen S, Chen X, Wang B, Xie F, Ouyang Z, Jiang Z, Fu A, Hu B, Yin H, Qiu X, Yu F, Du X, Hao W, Liu Y, Wang H, Wang L, Yu X, Xiao Y, Liu C, Xiao J, Zhou Y, Yang W, Zhang B, Luo W. Intronic (TTTGA)
n
insertion in
SAMD12
also causes familial cortical myoclonic tremor with epilepsy. Mov Disord 2019; 34:1571-1576. [PMID: 31483537 DOI: 10.1002/mds.27832] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 07/02/2019] [Accepted: 07/29/2019] [Indexed: 11/09/2022] Open
Affiliation(s)
- Zhidong Cen
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
- Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - You Chen
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
- Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Dehao Yang
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
- Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Qingchen Zhu
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences University of Chinese Academy of Sciences, Chinese Academy of Sciences Shanghai China
| | - Si Chen
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
- Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Xinhui Chen
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Bo Wang
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Fei Xie
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
- Department of Neurology Sir Run Run Shaw Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Zhiyuan Ouyang
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Zhengwen Jiang
- Genesky Diagnostics Inc, Biobay, SIP Suzhou Jiangsu China
| | - Aisi Fu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education and School of Pharmaceutical Sciences Wuhan University Wuhan Hubei China
| | - Ben Hu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education and School of Pharmaceutical Sciences Wuhan University Wuhan Hubei China
| | - Houmin Yin
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Xia Qiu
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Feng Yu
- Genesky Diagnostics Inc, Biobay, SIP Suzhou Jiangsu China
| | - Xiaoping Du
- Epilepsy Center, Department of Neurosurgery Humanity Hospital Xiamen Fujian China
- Department of Neurology, West District The Second Hospital of Shanxi Medical University Taiyuan Shanxi China
| | - Weicheng Hao
- Department of Neurology, West District The Second Hospital of Shanxi Medical University Taiyuan Shanxi China
| | - Yuxi Liu
- Institute of Epilepsy Shanxi Medical University Taiyuan Shanxi China
| | - Haotian Wang
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
- Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Lebo Wang
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Xiafei Yu
- Department of Biophysics, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Yichuan Xiao
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences University of Chinese Academy of Sciences, Chinese Academy of Sciences Shanghai China
| | - Chunyu Liu
- Department of Psychiatry SUNY Upstate Medical University Syracuse New York USA
| | - Jianfeng Xiao
- Department of Neurology University of Tennessee Health Science Center Memphis Tennessee USA
| | - Yongxing Zhou
- Department of Neurology MedStar St Mary's Hospital/Georgetown University Hospital, MedStar Medical Group Leonardtown Maryland USA
| | - Wei Yang
- Department of Biophysics, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Baorong Zhang
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
| | - Wei Luo
- Department of Neurology The Second Affiliated Hospital, Zhejiang University School of Medicine Hangzhou Zhejiang China
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49
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Jenquin JR, Yang H, Huigens RW, Nakamori M, Berglund JA. Combination Treatment of Erythromycin and Furamidine Provides Additive and Synergistic Rescue of Mis-Splicing in Myotonic Dystrophy Type 1 Models. ACS Pharmacol Transl Sci 2019; 2:247-263. [PMID: 31485578 DOI: 10.1021/acsptsci.9b00020] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Myotonic dystrophy type 1 (DM1) is a multi-systemic disease that presents with clinical symptoms including myotonia, cardiac dysfunction and cognitive impairment. DM1 is caused by a CTG expansion in the 3' UTR of the DMPK gene. The transcribed expanded CUG repeat RNA sequester the muscleblind-like (MBNL) and up-regulate the CUG-BP Elav-like (CELF) families of RNA-binding proteins leading to global mis-regulation of RNA processing and altered gene expression. Currently, there are no disease-targeting treatments for DM1. Given the multi-step pathogenic mechanism, combination therapies targeting different aspects of the disease mechanism may be a viable therapeutic approach. Here, as proof-of-concept, we studied a combination of two previously characterized small molecules, erythromycin and furamidine, in two DM1 models. In DM1 patient-derived myotubes, rescue of mis-splicing was observed with little to no cell toxicity. In a DM1 mouse model, a combination of erythromycin and the prodrug of furamidine (pafuramidine), administered orally, displayed both additive and synergistic mis-splicing rescue. Gene expression was only modestly affected and over 40 % of the genes showing significant expression changes were rescued back toward WT expression levels. Further, the combination treatment partially rescued the myotonia phenotype in the DM1 mouse. This combination treatment showed a high degree of mis-splicing rescue coupled with low off-target gene expression changes. These results indicate that combination therapies are a promising therapeutic approach for DM1.
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Affiliation(s)
- Jana R Jenquin
- Department of Biochemistry & Molecular Biology, Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, Florida, 32610, USA
| | - Hongfen Yang
- Department of Medicinal Chemistry, Center for Natural Products Drug Discovery and Development, College of Pharmacy, University of Florida, Gainesville, FL, 32610, USA
| | - Robert W Huigens
- Department of Medicinal Chemistry, Center for Natural Products Drug Discovery and Development, College of Pharmacy, University of Florida, Gainesville, FL, 32610, USA
| | - Masayuki Nakamori
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - J Andrew Berglund
- Department of Biochemistry & Molecular Biology, Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, Florida, 32610, USA.,Department of Biological Sciences, RNA Institute, College of Arts and Sciences, University at Albany-SUNY, Albany, New York, 12222, USA
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50
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Cen Z, Jiang Z, Chen Y, Zheng X, Xie F, Yang X, Lu X, Ouyang Z, Wu H, Chen S, Yin H, Qiu X, Wang S, Ding M, Tang Y, Yu F, Li C, Wang T, Ishiura H, Tsuji S, Jiao C, Liu C, Xiao J, Luo W. Intronic pentanucleotide TTTCA repeat insertion in the SAMD12 gene causes familial cortical myoclonic tremor with epilepsy type 1. Brain 2019; 141:2280-2288. [PMID: 29939203 DOI: 10.1093/brain/awy160] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 04/18/2018] [Indexed: 12/16/2022] Open
Abstract
Familial cortical myoclonic tremor with epilepsy is an autosomal dominant neurodegenerative disease, characterized by cortical tremor and epileptic seizures. Although four subtypes (types 1-4) mapped on different chromosomes (8q24, 2p11.1-q12.2, 5p15.31-p15.1 and 3q26.32-3q28) have been reported, the causative gene has not yet been identified. Here, we report the genetic study in a cohort of 20 Chinese pedigrees with familial cortical myoclonic tremor with epilepsy. Linkage and haplotype analysis in 11 pedigrees revealed maximum two-point logarithm of the odds (LOD) scores from 1.64 to 3.77 (LOD scores in five pedigrees were >3.0) in chromosomal region 8q24 and narrowed the candidate region to an interval of 4.9 Mb. Using whole-genome sequencing, long-range polymerase chain reaction and repeat-primed polymerase chain reaction, we identified an intronic pentanucleotide (TTTCA)n insertion in the SAMD12 gene as the cause, which co-segregated with the disease among the 11 pedigrees mapped on 8q24 and additional seven unmapped pedigrees. Only two pedigrees did not contain the (TTTCA)n insertion. Repeat-primed polymerase chain reaction revealed that the sizes of (TTTCA)n insertion in all affected members were larger than 105 repeats. The same pentanucleotide insertion (ATTTCATTTC)58 has been reported to form RNA foci resulting in neurotoxicity in spinocerebellar ataxia type 37, which suggests the similar pathogenic process in familial cortical myoclonic tremor with epilepsy type 1.
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Affiliation(s)
- Zhidong Cen
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zhengwen Jiang
- Genesky Diagnostics Inc, Biobay, SIP, Suzhou, Jiangsu, China
| | - You Chen
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaosheng Zheng
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Intensive Care Unit, Zhejiang Hospital, Hangzhou, Zhejiang, China
| | - Fei Xie
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Neurology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaodong Yang
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xingjiao Lu
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Neurology, Zhejiang Hospital, Hangzhou, Zhejiang, China
| | - Zhiyuan Ouyang
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hongwei Wu
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Neurology, Lishui People's Hospital, Lishui, Zhejiang, China
| | - Si Chen
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Cancer Institute, Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Houmin Yin
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xia Qiu
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shuang Wang
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Meiping Ding
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yelei Tang
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Feng Yu
- Genesky Diagnostics Inc, Biobay, SIP, Suzhou, Jiangsu, China
| | - Caihua Li
- Genesky Biotechnologies Inc., Shanghai, China
| | - Tao Wang
- Genesky Biotechnologies Inc., Shanghai, China
| | - Hiroyuki Ishiura
- Department of Neurology, Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shoji Tsuji
- Department of Molecular Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Institute of Medical Genomics, International University of Health and Welfare, Chiba, Japan
| | - Chuan Jiao
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Chunyu Liu
- Department of Psychiatry, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Jianfeng Xiao
- Department of Neurology, University of Tennessee Health Science Center, Memphis, Tennessee, USA
| | - Wei Luo
- Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
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