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Maltby CJ, Krans A, Grudzien SJ, Palacios Y, Muiños J, Suárez A, Asher M, Willey S, Van Deynze K, Mumm C, Boyle AP, Cortese A, Ndayisaba A, Khurana V, Barmada SJ, Dijkstra AA, Todd PK. AAGGG repeat expansions trigger RFC1-independent synaptic dysregulation in human CANVAS neurons. SCIENCE ADVANCES 2024; 10:eadn2321. [PMID: 39231235 PMCID: PMC11373605 DOI: 10.1126/sciadv.adn2321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 07/30/2024] [Indexed: 09/06/2024]
Abstract
Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a recessively inherited neurodegenerative disorder caused by intronic biallelic, nonreference CCCTT/AAGGG repeat expansions within RFC1. To investigate how these repeats cause disease, we generated patient induced pluripotent stem cell-derived neurons (iNeurons). CCCTT/AAGGG repeat expansions do not alter neuronal RFC1 splicing, expression, or DNA repair pathway function. In reporter assays, AAGGG repeats are translated into pentapeptide repeat proteins. However, these proteins and repeat RNA foci were not detected in iNeurons, and overexpression of these repeats failed to induce neuronal toxicity. CANVAS iNeurons exhibit defects in neuronal development and diminished synaptic connectivity that is rescued by CRISPR deletion of a single expanded AAGGG allele. These deficits were neither replicated by RFC1 knockdown in control iNeurons nor rescued by RFC1 reprovision in CANVAS iNeurons. These findings support a repeat-dependent but RFC1 protein-independent cause of neuronal dysfunction in CANVAS, with 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
| | - Sydney Willey
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Kinsey Van Deynze
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Camille Mumm
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Alan P Boyle
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Andrea Cortese
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- Department of Brain and Behaviour Sciences, University of Pavia, Pavia 27100, Italy
| | - Alain Ndayisaba
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Vikram Khurana
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Harvard Stem Cell Institute, 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, Netherlands
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, 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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2
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Zhang B, Zhang J, Chen H, Qiao D, Guo F, Hu X, Qin C, Jin X, Zhang K, Wang C, Cui H, Li S. Role of FMRP in AKT/mTOR pathway-mediated hippocampal autophagy in fragile X syndrome. Prog Neuropsychopharmacol Biol Psychiatry 2024; 134:111036. [PMID: 38823765 DOI: 10.1016/j.pnpbp.2024.111036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 05/05/2024] [Accepted: 05/22/2024] [Indexed: 06/03/2024]
Abstract
Fragile X syndrome (FXS) is caused by epigenetic silencing of the Fmr1 gene, leading to the deletion of the coding protein FMRP. FXS induces abnormal hippocampal autophagy and mTOR overactivation. However, it remains unclear whether FMRP regulates hippocampal autophagy through the AKT/mTOR pathway, which influences the neural behavior of FXS. Our study revealed that FMRP deficiency increased the protein levels of p-ULK-1 and p62 and decreased LC3II/LC3I level in Fmr1 knockout (KO) mice. The mouse hippocampal neuronal cell line HT22 with knockdown of Fmr1 by lentivirus showed that the protein levels of p-ULK-1 and p62 were increased, whereas LC3II/LC3I was unchanged. Further observations revealed that FMRP deficiency obstructed autophagic flow in HT22 cells. Therefore, FMRP deficiency inhibited autophagy in the mouse hippocampus and HT22 cells. Moreover, FMRP deficiency increased reactive oxygen species (ROS) level, decreased the co-localization between the mitochondrial outer membrane proteins TOM20 and LC3 in HT22 cells, and caused a decrease in the mitochondrial autophagy protein PINK1 in HT22 cells and Fmr1 KO mice, indicating that FMRP deficiency caused mitochondrial autophagy disorder in HT22 cells and Fmr1 KO mice. To explore the mechanism by which FMRP deficiency inhibits autophagy, we examined the AKT/mTOR signaling pathway in the hippocampus of Fmr1 KO mice, found that FMRP deficiency caused overactivation of the AKT/mTOR pathway. Rapamycin-mediated mTOR inhibition activated and enhanced mitochondrial autophagy. Finally, we examined whether rapamycin affected the neurobehavior of Fmr1 KO mice. The Fmr1 KO mice exhibited stereotypical behavior, impaired social ability, and learning and memory impairment, while rapamycin treatment improved behavioral disorders in Fmr1 KO mice. Thus, our study revealed the molecular mechanism by which FMRP regulates autophagy function, clarifying the role of hippocampal neuron mitochondrial autophagy in the pathogenesis of FXS, and providing novel insights into potential therapeutic targets of FXS.
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Affiliation(s)
- Bohan Zhang
- Department of Human Anatomy, Neuroscience Research Center, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurodegenerative Disease Mechanism, Hebei Medical University, Shijiazhuang 050017, China
| | - Jingbao Zhang
- Grade 2020, Basic Medicine, Hebei Medical University, Shijiazhuang 050017, Hebei, China
| | - Huan Chen
- Department of Human Anatomy, Neuroscience Research Center, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurodegenerative Disease Mechanism, Hebei Medical University, Shijiazhuang 050017, China
| | - Dan Qiao
- Department of Human Anatomy, Neuroscience Research Center, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurodegenerative Disease Mechanism, Hebei Medical University, Shijiazhuang 050017, China
| | - Fangzhen Guo
- Department of Human Anatomy, Neuroscience Research Center, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurodegenerative Disease Mechanism, Hebei Medical University, Shijiazhuang 050017, China
| | - Xiangting Hu
- Grade 2020, Basic Medicine, Hebei Medical University, Shijiazhuang 050017, Hebei, China
| | - Chao Qin
- Grade 2021, Basic Medicine, Hebei Medical University, Shijiazhuang 050017, Hebei, China
| | - Xiaowen Jin
- Grade 2021, Basic Medicine, Hebei Medical University, Shijiazhuang 050017, Hebei, China
| | - Kaixi Zhang
- Grade 2021, 5+3 Integrated pediatrics, Hebei Medical University, Shijiazhuang 050017, Hebei, China
| | - Chang Wang
- Department of Human Anatomy, Neuroscience Research Center, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurodegenerative Disease Mechanism, Hebei Medical University, Shijiazhuang 050017, China
| | - Huixian Cui
- Department of Human Anatomy, Neuroscience Research Center, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurodegenerative Disease Mechanism, Hebei Medical University, Shijiazhuang 050017, China.
| | - Sha Li
- Department of Human Anatomy, Neuroscience Research Center, Hebei Medical University, Shijiazhuang 050017, China; Hebei Key Laboratory of Neurodegenerative Disease Mechanism, Hebei Medical University, Shijiazhuang 050017, China; The Key Laboratory of Neural and Vascular Biology of Ministry of Education, Shijiazhuang 050017, China.
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3
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Figueroa KP, Gross C, Buena-Atienza E, Paul S, Gandelman M, Kakar N, Sturm M, Casadei N, Admard J, Park J, Zühlke C, Hellenbroich Y, Pozojevic J, Balachandran S, Händler K, Zittel S, Timmann D, Erdlenbruch F, Herrmann L, Feindt T, Zenker M, Klopstock T, Dufke C, Scoles DR, Koeppen A, Spielmann M, Riess O, Ossowski S, Haack TB, Pulst SM. A GGC-repeat expansion in ZFHX3 encoding polyglycine causes spinocerebellar ataxia type 4 and impairs autophagy. Nat Genet 2024; 56:1080-1089. [PMID: 38684900 DOI: 10.1038/s41588-024-01719-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 03/18/2024] [Indexed: 05/02/2024]
Abstract
Despite linkage to chromosome 16q in 1996, the mutation causing spinocerebellar ataxia type 4 (SCA4), a late-onset sensory and cerebellar ataxia, remained unknown. Here, using long-read single-strand whole-genome sequencing (LR-GS), we identified a heterozygous GGC-repeat expansion in a large Utah pedigree encoding polyglycine (polyG) in zinc finger homeobox protein 3 (ZFHX3), also known as AT-binding transcription factor 1 (ATBF1). We queried 6,495 genome sequencing datasets and identified the repeat expansion in seven additional pedigrees. Ultrarare DNA variants near the repeat expansion indicate a common distant founder event in Sweden. Intranuclear ZFHX3-p62-ubiquitin aggregates were abundant in SCA4 basis pontis neurons. In fibroblasts and induced pluripotent stem cells, the GGC expansion led to increased ZFHX3 protein levels and abnormal autophagy, which were normalized with small interfering RNA-mediated ZFHX3 knockdown in both cell types. Improving autophagy points to a therapeutic avenue for this novel polyG disease. The coding GGC-repeat expansion in an extremely G+C-rich region was not detectable by short-read whole-exome sequencing, which demonstrates the power of LR-GS for variant discovery.
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Affiliation(s)
- Karla P Figueroa
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Caspar Gross
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen, Tübingen, Germany
| | - Elena Buena-Atienza
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen, Tübingen, Germany
| | - Sharan Paul
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Mandi Gandelman
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | - Naseebullah Kakar
- Institute of Human Genetics, University Medical Center Schleswig-Holstein, University of Lübeck and Kiel University, Lübeck, Germany
- Department of Biotechnology, FLS&I, BUITEMS, Quetta, Pakistan
| | - Marc Sturm
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Nicolas Casadei
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen, Tübingen, Germany
| | - Jakob Admard
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen, Tübingen, Germany
| | - Joohyun Park
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Christine Zühlke
- Institute of Human Genetics, University Medical Center Schleswig-Holstein, University of Lübeck and Kiel University, Lübeck, Germany
| | - Yorck Hellenbroich
- Institute of Human Genetics, University Medical Center Schleswig-Holstein, University of Lübeck and Kiel University, Lübeck, Germany
| | - Jelena Pozojevic
- Institute of Human Genetics, University Medical Center Schleswig-Holstein, University of Lübeck and Kiel University, Lübeck, Germany
| | - Saranya Balachandran
- Institute of Human Genetics, University Medical Center Schleswig-Holstein, University of Lübeck and Kiel University, Lübeck, Germany
| | - Kristian Händler
- Institute of Human Genetics, University Medical Center Schleswig-Holstein, University of Lübeck and Kiel University, Lübeck, Germany
| | - Simone Zittel
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Dagmar Timmann
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Friedrich Erdlenbruch
- Department of Neurology and Center for Translational Neuro- and Behavioral Sciences (C-TNBS), Essen University Hospital, University of Duisburg-Essen, Essen, Germany
| | - Laura Herrmann
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Martin Zenker
- Institute of Human Genetics, University Hospital Magdeburg and Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany
| | - Thomas Klopstock
- Department of Neurology with Friedrich-Baur-Institute, University Hospital of Ludwig-Maximilians-Universität München, Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Claudia Dufke
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Daniel R Scoles
- Department of Neurology, University of Utah, Salt Lake City, UT, USA
| | | | - Malte Spielmann
- Institute of Human Genetics, University Medical Center Schleswig-Holstein, University of Lübeck and Kiel University, Lübeck, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg, Lübeck, Kiel, Lübeck, Germany
| | - Olaf Riess
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany.
- NGS Competence Center Tübingen, Tübingen, Germany.
| | - Stephan Ossowski
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen, Tübingen, Germany
- Institute for Bioinformatics and Medical Informatics (IBMI), University of Tübingen, Tübingen, Germany
| | - Tobias B Haack
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
- NGS Competence Center Tübingen, Tübingen, Germany
| | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, UT, USA.
- Clinical Neurosciences Center, University of Utah Hospitals and Clinics, Salt Lake City, UT, USA.
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4
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Zhang Y, Liu X, Li Z, Li H, Miao Z, Wan B, Xu X. Advances on the Mechanisms and Therapeutic Strategies in Non-coding CGG Repeat Expansion Diseases. Mol Neurobiol 2024:10.1007/s12035-024-04239-9. [PMID: 38780719 DOI: 10.1007/s12035-024-04239-9] [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: 11/20/2023] [Accepted: 05/02/2024] [Indexed: 05/25/2024]
Abstract
Non-coding CGG repeat expansions within the 5' untranslated region are implicated in a range of neurological disorders, including fragile X-associated tremor/ataxia syndrome, oculopharyngeal myopathy with leukodystrophy, and oculopharyngodistal myopathy. This review outlined the general characteristics of diseases associated with non-coding CGG repeat expansions, detailing their clinical manifestations and neuroimaging patterns, which often overlap and indicate shared pathophysiological traits. We summarized the underlying molecular mechanisms of these disorders, providing new insights into the roles that DNA, RNA, and toxic proteins play. Understanding these mechanisms is crucial for the development of targeted therapeutic strategies. These strategies include a range of approaches, such as antisense oligonucleotides, RNA interference, genomic DNA editing, small molecule interventions, and other treatments aimed at correcting the dysregulated processes inherent in these disorders. A deeper understanding of the shared mechanisms among non-coding CGG repeat expansion disorders may hold the potential to catalyze the development of innovative therapies, ultimately offering relief to individuals grappling with these debilitating neurological conditions.
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Affiliation(s)
- Yutong Zhang
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
| | - Xuan Liu
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
| | - Zeheng Li
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
| | - Hao Li
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
- Department of Neurology, The Fourth Affiliated Hospital of Soochow University, Suzhou, 215124, China
| | - Zhigang Miao
- The Institute of Neuroscience, Soochow University, Suzhou City, China
| | - Bo Wan
- The Institute of Neuroscience, Soochow University, Suzhou City, China
| | - Xingshun Xu
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China.
- The Institute of Neuroscience, Soochow University, Suzhou City, China.
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, 215000, China.
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5
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Tak Y, Tassone F, Hagerman RJ. Case Series: Vestibular Migraines in Fragile X Premutation Carriers. J Clin Med 2024; 13:504. [PMID: 38256638 PMCID: PMC10816080 DOI: 10.3390/jcm13020504] [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: 12/20/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024] Open
Abstract
BACKGROUND Vestibular migraine (VM) is one of the most common causes of recurrent vertigo and presents with a history of spontaneous or positional vertigo with a history of migraine headaches. While research has identified a high prevalence of migraine headaches and vestibular deficits among fragile X premutation carriers, there has been no discussion about VM within this population. OBJECTIVE This case series and review seeks to describe the clinical characteristics and pathophysiology of VM among individuals with the fragile X premutation. We also seek to discuss treatment and future steps in addressing VM in this population. METHODS A review of the literature regarding vestibular migraine and presentation of migraine headaches and vestibular deficits among premutation carriers was performed. A detailed clinical history of migraine headaches and vertigo was obtained from three patients with the fragile X premutation seen by the senior author (RJH). RESULTS All three cases first developed symptoms of migraine headaches earlier in life, with the development of VM near menopause. Two of the three cases developed progressive balance issues following the development of VM. All three cases found that their VM episodes were improved or resolved with pharmacological and/or lifestyle interventions. CONCLUSIONS It is important to recognize VM among premutation carriers because beneficial treatments are available. Future studies are needed regarding the prevalence of VM and the relationship to subsequent FXTAS. The pathophysiology of VM remains uncertain but possibilities include mitochondrial abnormalities, cranial nerve VIII toxicity secondary to neurotoxic protein accumulation, and calcitonin gene-related peptide (CGRP) signaling dysfunction due to altered levels of fragile X messenger ribonucleoprotein (FMRP).
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Affiliation(s)
- YeEun Tak
- University of California Davis School of Medicine, Sacramento Campus, Sacramento, CA 95817, USA; (Y.T.); (F.T.)
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Health, Sacramento, CA 95616, USA
| | - Flora Tassone
- University of California Davis School of Medicine, Sacramento Campus, Sacramento, CA 95817, USA; (Y.T.); (F.T.)
- Department of Biochemistry and Molecular Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Randi J. Hagerman
- University of California Davis School of Medicine, Sacramento Campus, Sacramento, CA 95817, USA; (Y.T.); (F.T.)
- Department of Pediatrics, University of California Davis Health, Sacramento, CA 95817, USA
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6
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Tassone F, Protic D, Allen EG, Archibald AD, Baud A, Brown TW, Budimirovic DB, Cohen J, Dufour B, Eiges R, Elvassore N, Gabis LV, Grudzien SJ, Hall DA, Hessl D, Hogan A, Hunter JE, Jin P, Jiraanont P, Klusek J, Kooy RF, Kraan CM, Laterza C, Lee A, Lipworth K, Losh M, Loesch D, Lozano R, Mailick MR, Manolopoulos A, Martinez-Cerdeno V, McLennan Y, Miller RM, Montanaro FAM, Mosconi MW, Potter SN, Raspa M, Rivera SM, Shelly K, Todd PK, Tutak K, Wang JY, Wheeler A, Winarni TI, Zafarullah M, Hagerman RJ. Insight and Recommendations for Fragile X-Premutation-Associated Conditions from the Fifth International Conference on FMR1 Premutation. Cells 2023; 12:2330. [PMID: 37759552 PMCID: PMC10529056 DOI: 10.3390/cells12182330] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/09/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
The premutation of the fragile X messenger ribonucleoprotein 1 (FMR1) gene is characterized by an expansion of the CGG trinucleotide repeats (55 to 200 CGGs) in the 5' untranslated region and increased levels of FMR1 mRNA. Molecular mechanisms leading to fragile X-premutation-associated conditions (FXPAC) include cotranscriptional R-loop formations, FMR1 mRNA toxicity through both RNA gelation into nuclear foci and sequestration of various CGG-repeat-binding proteins, and the repeat-associated non-AUG (RAN)-initiated translation of potentially toxic proteins. Such molecular mechanisms contribute to subsequent consequences, including mitochondrial dysfunction and neuronal death. Clinically, premutation carriers may exhibit a wide range of symptoms and phenotypes. Any of the problems associated with the premutation can appropriately be called FXPAC. Fragile X-associated tremor/ataxia syndrome (FXTAS), fragile X-associated primary ovarian insufficiency (FXPOI), and fragile X-associated neuropsychiatric disorders (FXAND) can fall under FXPAC. Understanding the molecular and clinical aspects of the premutation of the FMR1 gene is crucial for the accurate diagnosis, genetic counseling, and appropriate management of affected individuals and families. This paper summarizes all the known problems associated with the premutation and documents the presentations and discussions that occurred at the International Premutation Conference, which took place in New Zealand in 2023.
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Affiliation(s)
- Flora Tassone
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
| | - Dragana Protic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11129 Belgrade, Serbia;
- Fragile X Clinic, Special Hospital for Cerebral Palsy and Developmental Neurology, 11040 Belgrade, Serbia
| | - Emily Graves Allen
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA; (E.G.A.); (P.J.); (K.S.)
| | - Alison D. Archibald
- Victorian Clinical Genetics Services, Royal Children’s Hospital, Melbourne, VIC 3052, Australia;
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC 3052, Australia;
- Genomics in Society Group, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, VIC 3052, Australia
| | - Anna Baud
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznan, Poland; (A.B.); (K.T.)
| | - Ted W. Brown
- Central Clinical School, University of Sydney, Sydney, NSW 2006, Australia;
- Fragile X Association of Australia, Brookvale, NSW 2100, Australia;
- NYS Institute for Basic Research in Developmental Disabilities, New York, NY 10314, USA
| | - Dejan B. Budimirovic
- Department of Psychiatry, Fragile X Clinic, Kennedy Krieger Institute, Baltimore, MD 21205, USA;
- Department of Psychiatry & Behavioral Sciences-Child Psychiatry, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Jonathan Cohen
- Fragile X Alliance Clinic, Melbourne, VIC 3161, Australia;
| | - Brett Dufour
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
- Department of Pathology and Laboratory Medicine, Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
| | - Rachel Eiges
- Stem Cell Research Laboratory, Medical Genetics Institute, Shaare Zedek Medical Center Affiliated with the Hebrew University School of Medicine, Jerusalem 91031, Israel;
| | - Nicola Elvassore
- Veneto Institute of Molecular Medicine (VIMM), 35129 Padova, Italy; (N.E.); (C.L.)
- Department of Industrial Engineering, University of Padova, 35131 Padova, Italy
| | - Lidia V. Gabis
- Keshet Autism Center Maccabi Wolfson, Holon 5822012, Israel;
- Faculty of Medicine, Tel-Aviv University, Tel Aviv 6997801, Israel
| | - Samantha J. Grudzien
- Department of Neurology, University of Michigan, 4148 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA; (S.J.G.); (P.K.T.)
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Deborah A. Hall
- Department of Neurological Sciences, Rush University, Chicago, IL 60612, USA;
| | - David Hessl
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
| | - Abigail Hogan
- Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA; (A.H.); (J.K.)
| | - Jessica Ezzell Hunter
- RTI International, Research Triangle Park, NC 27709, USA; (J.E.H.); (S.N.P.); (M.R.); (A.W.)
| | - Peng Jin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA; (E.G.A.); (P.J.); (K.S.)
| | - Poonnada Jiraanont
- Faculty of Medicine, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand;
| | - Jessica Klusek
- Department of Communication Sciences and Disorders, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA; (A.H.); (J.K.)
| | - R. Frank Kooy
- Department of Medical Genetics, University of Antwerp, 2000 Antwerp, Belgium;
| | - Claudine M. Kraan
- Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC 3052, Australia;
- Diagnosis and Development, Murdoch Children’s Research Institute, Melbourne, VIC 3052, Australia
| | - Cecilia Laterza
- Veneto Institute of Molecular Medicine (VIMM), 35129 Padova, Italy; (N.E.); (C.L.)
- Department of Industrial Engineering, University of Padova, 35131 Padova, Italy
| | - Andrea Lee
- Fragile X New Zealand, Nelson 7040, New Zealand;
| | - Karen Lipworth
- Fragile X Association of Australia, Brookvale, NSW 2100, Australia;
| | - Molly Losh
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60201, USA;
| | - Danuta Loesch
- School of Psychology and Public Health, La Trobe University, Melbourne, VIC 3086, Australia;
| | - Reymundo Lozano
- Departments of Genetics and Genomic Sciences and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
| | - Marsha R. Mailick
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA;
| | - Apostolos Manolopoulos
- Intramural Research Program, Laboratory of Clinical Investigation, National Institute on Aging, Baltimore, MD 21224, USA;
| | - Veronica Martinez-Cerdeno
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
- Department of Pathology and Laboratory Medicine, Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
| | - Yingratana McLennan
- Department of Pathology and Laboratory Medicine, Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children of Northern California, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
| | | | - Federica Alice Maria Montanaro
- Child and Adolescent Neuropsychiatry Unit, Department of Neuroscience, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy;
- Department of Education, Psychology, Communication, University of Bari Aldo Moro, 70121 Bari, Italy
| | - Matthew W. Mosconi
- Schiefelbusch Institute for Life Span Studies, University of Kansas, Lawrence, KS 66045, USA;
- Clinical Child Psychology Program, University of Kansas, Lawrence, KS 66045, USA
- Kansas Center for Autism Research and Training (K-CART), University of Kansas, Lawrence, KS 66045, USA
| | - Sarah Nelson Potter
- RTI International, Research Triangle Park, NC 27709, USA; (J.E.H.); (S.N.P.); (M.R.); (A.W.)
| | - Melissa Raspa
- RTI International, Research Triangle Park, NC 27709, USA; (J.E.H.); (S.N.P.); (M.R.); (A.W.)
| | - Susan M. Rivera
- Department of Psychology, University of Maryland, College Park, MD 20742, USA;
| | - Katharine Shelly
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA; (E.G.A.); (P.J.); (K.S.)
| | - Peter K. Todd
- Department of Neurology, University of Michigan, 4148 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA; (S.J.G.); (P.K.T.)
- Ann Arbor Veterans Administration Healthcare, Ann Arbor, MI 48105, USA
| | - Katarzyna Tutak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznan, Poland; (A.B.); (K.T.)
| | - Jun Yi Wang
- Center for Mind and Brain, University of California Davis, Davis, CA 95618, USA;
| | - Anne Wheeler
- RTI International, Research Triangle Park, NC 27709, USA; (J.E.H.); (S.N.P.); (M.R.); (A.W.)
| | - Tri Indah Winarni
- Center for Biomedical Research (CEBIOR), Faculty of Medicine, Universitas Diponegoro, Semarang 502754, Central Java, Indonesia;
| | - Marwa Zafarullah
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA;
| | - Randi J. Hagerman
- MIND Institute, University of California Davis, Davis, CA 95817, USA; (B.D.); (D.H.); (V.M.-C.)
- Department of Pediatrics, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
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7
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Zhang S, Pei G, Li B, Li P, Lin Y. Abnormal phase separation of biomacromolecules in human diseases. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1133-1152. [PMID: 37475546 PMCID: PMC10423695 DOI: 10.3724/abbs.2023139] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 07/07/2023] [Indexed: 07/22/2023] Open
Abstract
Membrane-less organelles (MLOs) formed through liquid-liquid phase separation (LLPS) are associated with numerous important biological functions, but the abnormal phase separation will also dysregulate the physiological processes. Emerging evidence points to the importance of LLPS in human health and diseases. Nevertheless, despite recent advancements, our knowledge of the molecular relationship between LLPS and diseases is frequently incomplete. In this review, we outline our current understanding about how aberrant LLPS affects developmental disorders, tandem repeat disorders, cancers and viral infection. We also examine disease mechanisms driven by aberrant condensates, and highlight potential treatment approaches. This study seeks to expand our understanding of LLPS by providing a valuable new paradigm for understanding phase separation and human disorders, as well as to further translate our current knowledge regarding LLPS into therapeutic discoveries.
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Affiliation(s)
- Songhao Zhang
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- IDG/McGovern Institute for Brain Research at Tsinghua UniversityBeijing100084China
| | - Gaofeng Pei
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- Frontier Research Center for Biological StructureTsinghua UniversityBeijing100084China
| | - Boya Li
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- IDG/McGovern Institute for Brain Research at Tsinghua UniversityBeijing100084China
| | - Pilong Li
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- Frontier Research Center for Biological StructureTsinghua UniversityBeijing100084China
| | - Yi Lin
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- IDG/McGovern Institute for Brain Research at Tsinghua UniversityBeijing100084China
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8
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Wright SE, Todd PK. Native functions of short tandem repeats. eLife 2023; 12:e84043. [PMID: 36940239 PMCID: PMC10027321 DOI: 10.7554/elife.84043] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 03/08/2023] [Indexed: 03/21/2023] Open
Abstract
Over a third of the human genome is comprised of repetitive sequences, including more than a million short tandem repeats (STRs). While studies of the pathologic consequences of repeat expansions that cause syndromic human diseases are extensive, the potential native functions of STRs are often ignored. Here, we summarize a growing body of research into the normal biological functions for repetitive elements across the genome, with a particular focus on the roles of STRs in regulating gene expression. We propose reconceptualizing the pathogenic consequences of repeat expansions as aberrancies in normal gene regulation. From this altered viewpoint, we predict that future work will reveal broader roles for STRs in neuronal function and as risk alleles for more common human neurological diseases.
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Affiliation(s)
- Shannon E Wright
- Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
- Neuroscience Graduate Program, University of Michigan–Ann ArborAnn ArborUnited States
- Department of Neuroscience, Picower InstituteCambridgeUnited States
| | - Peter K Todd
- Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
- VA Ann Arbor Healthcare SystemAnn ArborUnited States
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9
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Reyes CJF, Asano K. Between Order and Chaos: Understanding the Mechanism and Pathology of RAN Translation. Biol Pharm Bull 2023; 46:139-146. [PMID: 36724941 DOI: 10.1248/bpb.b22-00448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Repeat-associated non-AUG (RAN) translation is a pathogenic mechanism in which repetitive sequences are translated into aggregation-prone proteins from multiple reading frames, even without a canonical AUG start codon. Since its discovery in spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1), RAN translation is now known to occur in the context of 12 disease-linked repeat expansions. This review discusses recent advances in understanding the regulatory mechanisms controlling RAN translation and its contribution to the pathophysiology of repeat expansion diseases. We discuss the key findings in the context of Fragile X Tremor Ataxia Syndrome (FXTAS), a neurodegenerative disorder caused by a CGG repeat expansion in the 5' untranslated region of FMR1.
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Affiliation(s)
| | - Katsura Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University.,Laboratory of Translational Control Study, Graduate School of Integrated Sciences for Life, Hiroshima University.,Hiroshima Research Center for Healthy Aging, Hiroshima University
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10
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Liu Q, Zhang K, Kang Y, Li Y, Deng P, Li Y, Tian Y, Sun Q, Tang Y, Xu K, Zhou Y, Wang JL, Guo J, Li JD, Xia K, Meng Q, Allen EG, Wen Z, Li Z, Jiang H, Shen L, Duan R, Yao B, Tang B, Jin P, Pan Y. Expression of expanded GGC repeats within NOTCH2NLC causes behavioral deficits and neurodegeneration in a mouse model of neuronal intranuclear inclusion disease. SCIENCE ADVANCES 2022; 8:eadd6391. [PMID: 36417528 PMCID: PMC9683706 DOI: 10.1126/sciadv.add6391] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
GGC repeat expansions within NOTCH2NLC have been identified as the genetic cause of neuronal intranuclear inclusion disease (NIID). To understand the molecular pathogenesis of NIID, here, we established both a transgenic mouse model and a human neural progenitor cells (hNPCs) model. Expression of the NOTCH2NLC with expanded GGC repeats produced widespread intranuclear and perinuclear polyglycine (polyG), polyalanine (polyA), and polyarginine (polyR) inclusions, leading to behavioral deficits and severe neurodegeneration, which faithfully mimicked the clinical and pathological features associated with NIID. Furthermore, conserved alternative splicing events were identified between the NIID mouse and hNPC models, among which was the enrichment of the binding motifs of hnRNPM, an RNA binding protein known as alternative splicing regulator. Expanded NOTCH2NLC-polyG and NOTCH2NLC-polyA could interact with and sequester hnRNPM, while overexpression of hnRNPM could ameliorate the cellular toxicity. These results together suggested that dysfunction of hnRNPM could play an important role in the molecular pathogenesis of NIID.
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Affiliation(s)
- Qiong Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Kailin Zhang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Yunhee Kang
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Yangping Li
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Penghui Deng
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Yujing Li
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Yun Tian
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Qiying Sun
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Yu Tang
- Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Keqin Xu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Yao Zhou
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Jun-Ling Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Jifeng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Jia-Da Li
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China
- Hunan International Scientific and Technological Cooperation Base of Animal Models for Human Disease, Changsha, Hunan 410008, China
| | - Kun Xia
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China
- Hengyang Medical School, University of South China, Hengyang, Hunan 421001, China
| | - Qingtuan Meng
- Multi-Omics Research Center for Brain Disorders, The First Affiliated Hospital of University of South China, Hengyang, Hunan 421001, China
| | - Emily G. Allen
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Zhexing Wen
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Ziyi Li
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Lu Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Ranhui Duan
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan 410008, China
| | - Bing Yao
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Corresponding author. (Y.P.); (P.J.); (B.T.)
| | - Peng Jin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
- Corresponding author. (Y.P.); (P.J.); (B.T.)
| | - Yongcheng Pan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
- Corresponding author. (Y.P.); (P.J.); (B.T.)
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11
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Rosario R, Stewart HL, Choudhury NR, Michlewski G, Charlet‐Berguerand N, Anderson RA. Evidence for a fragile X messenger ribonucleoprotein 1 (FMR1) mRNA gain-of-function toxicity mechanism contributing to the pathogenesis of fragile X-associated premature ovarian insufficiency. FASEB J 2022; 36:e22612. [PMID: 36250920 PMCID: PMC9828574 DOI: 10.1096/fj.202200468rr] [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: 03/25/2022] [Revised: 09/22/2022] [Accepted: 10/03/2022] [Indexed: 01/12/2023]
Abstract
Fragile X-associated premature ovarian insufficiency (FXPOI) is among a family of disorders caused by expansion of a CGG trinucleotide repeat sequence located in the 5' untranslated region (UTR) of the fragile X messenger ribonucleoprotein 1 (FMR1) gene on the X chromosome. Women with FXPOI have a depleted ovarian follicle population, resulting in amenorrhea, hypoestrogenism, and loss of fertility before the age of 40. FXPOI is caused by expansions of the CGG sequence to lengths between 55 and 200 repeats, known as a FMRI premutation, however the mechanism by which the premutation drives disease pathogenesis remains unclear. Two main hypotheses exist, which describe an mRNA toxic gain-of-function mechanism or a protein-based mechanism, where repeat-associated non-AUG (RAN) translation results in the production of an abnormal protein, called FMRpolyG. Here, we have developed an in vitro granulosa cell model of the FMR1 premutation by ectopically expressing CGG-repeat RNA and FMRpolyG protein. We show that expanded CGG-repeat RNA accumulated in intranuclear RNA structures, and these aggregates were able to cause significant granulosa cell death independent of FMRpolyG expression. Using an innovative RNA pulldown, mass spectrometry-based approach we have identified proteins that are specifically sequestered by CGG RNA aggregates in granulosa cells in vitro, and thus may be deregulated as consequence of this interaction. Furthermore, we have demonstrated reduced expression of three proteins identified via our RNA pulldown (FUS, PA2G4 and TRA2β) in ovarian follicles in a FMR1 premutation mouse model. Collectively, these data provide evidence for the contribution of an mRNA gain-of-function mechanism to FXPOI disease biology.
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Affiliation(s)
- Roseanne Rosario
- MRC Centre for Reproductive Health, Queen's Medical Research InstituteUniversity of EdinburghEdinburghUK,Biomedical SciencesUniversity of EdinburghEdinburghUK
| | - Hazel L. Stewart
- MRC Centre for Reproductive Health, Queen's Medical Research InstituteUniversity of EdinburghEdinburghUK
| | | | - Gracjan Michlewski
- Infection MedicineUniversity of EdinburghEdinburghUK,Zhejiang University‐University of Edinburgh InstituteZhejiang UniversityZhejiangP.R. China,Dioscuri Centre for RNA‐Protein Interactions in Human Health and DiseaseInternational Institute of Molecular and Cell Biology in WarsawWarsawPoland
| | - Nicholas Charlet‐Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC)INSERM U 1258, CNRS UMR 7104, Université of StrasbourgIllkirchFrance
| | - Richard A. Anderson
- MRC Centre for Reproductive Health, Queen's Medical Research InstituteUniversity of EdinburghEdinburghUK
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12
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Liu Y, Li H, Liu X, Wang B, Yang H, Wan B, Sun M, Xu X. Clinical and mechanism advances of neuronal intranuclear inclusion disease. Front Aging Neurosci 2022; 14:934725. [PMID: 36177481 PMCID: PMC9513122 DOI: 10.3389/fnagi.2022.934725] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Due to the high clinical heterogeneity of neuronal intranuclear inclusion disease (NIID), it is easy to misdiagnose this condition and is considered to be a rare progressive neurodegenerative disease. More evidence demonstrates that NIID involves not only the central nervous system but also multiple systems of the body and shows a variety of symptoms, which makes a clinical diagnosis of NIID more difficult. This review summarizes the clinical symptoms in different systems and demonstrates that NIID is a multiple-system intranuclear inclusion disease. In addition, the core triad symptoms in the central nervous system, such as dementia, parkinsonism, and psychiatric symptoms, are proposed as an important clue for the clinical diagnosis of NIID. Recent studies have demonstrated that expanded GGC repeats in the 5′-untranslated region of the NOTCH2NLC gene are the cause of NIID. The genetic advances and possible underlying mechanisms of NIID (expanded GGC repeat-induced DNA damage, RNA toxicity, and polyglycine-NOTCH2NLC protein toxicity) are briefly summarized in this review. Interestingly, inflammatory cell infiltration and inflammation were observed in the affected tissues of patients with NIID. As a downstream pathological process of NIID, inflammation could be a therapeutic target for NIID.
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Affiliation(s)
- Yueqi Liu
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, China
- Institute of Neuroscience, Soochow University, Suzhou, China
| | - Hao Li
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, China
- Institute of Neuroscience, Soochow University, Suzhou, China
| | - Xuan Liu
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Bin Wang
- Institute of Neuroscience, Soochow University, Suzhou, China
- Institute for Fetology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Hao Yang
- Institute for Fetology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Bo Wan
- Institute of Neuroscience, Soochow University, Suzhou, China
- Bo Wan,
| | - Miao Sun
- Institute for Fetology, The First Affiliated Hospital of Soochow University, Suzhou, China
- Miao Sun,
| | - Xingshun Xu
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, China
- Institute of Neuroscience, Soochow University, Suzhou, China
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, Jiangsu, China
- *Correspondence: Xingshun Xu,
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13
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Wright SE, Rodriguez CM, Monroe J, Xing J, Krans A, Flores BN, Barsur V, Ivanova MI, Koutmou KS, Barmada SJ, Todd PK. CGG repeats trigger translational frameshifts that generate aggregation-prone chimeric proteins. Nucleic Acids Res 2022; 50:8674-8689. [PMID: 35904811 PMCID: PMC9410890 DOI: 10.1093/nar/gkac626] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/13/2022] [Indexed: 11/25/2022] Open
Abstract
CGG repeat expansions in the FMR1 5’UTR cause the neurodegenerative disease Fragile X-associated tremor/ataxia syndrome (FXTAS). These repeats form stable RNA secondary structures that support aberrant translation in the absence of an AUG start codon (RAN translation), producing aggregate-prone peptides that accumulate within intranuclear neuronal inclusions and contribute to neurotoxicity. Here, we show that the most abundant RAN translation product, FMRpolyG, is markedly less toxic when generated from a construct with a non-repetitive alternating codon sequence in place of the CGG repeat. While exploring the mechanism of this differential toxicity, we observed a +1 translational frameshift within the CGG repeat from the arginine to glycine reading frame. Frameshifts occurred within the first few translated repeats and were triggered predominantly by RNA sequence and structural features. Short chimeric R/G peptides form aggregates distinct from those formed by either pure arginine or glycine, and these chimeras induce toxicity in cultured rodent neurons. Together, this work suggests that CGG repeats support translational frameshifting and that chimeric RAN translated peptides may contribute to CGG repeat-associated toxicity in FXTAS and related disorders.
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Affiliation(s)
- Shannon E Wright
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Caitlin M Rodriguez
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.,Department of Genetics, Stanford University School of Medicine, Stanford, CA 84305, USA
| | - Jeremy Monroe
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jiazheng Xing
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.,VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
| | - Brittany N Flores
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.,Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Venkatesha Barsur
- Department of Pathology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Magdalena I Ivanova
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.,Biophysics Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Kristin S Koutmou
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.,VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
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14
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Chen Y, Guo L, Han M, Zhang S, Chen Y, Zou J, Bai S, Cheng G, Zeng Y. Cerebellum Neuropathology and Motor Skill Deficits in Fragile X Syndrome. Int J Dev Neurosci 2022; 82:557-568. [DOI: 10.1002/jdn.10217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/11/2022] [Accepted: 07/14/2022] [Indexed: 11/06/2022] Open
Affiliation(s)
- Yu‐shan Chen
- Brain Science and Advanced Technology Institute, School of Medicine Wuhan University of Science and Technology Wuhan China
| | - Liu Guo
- Brain Science and Advanced Technology Institute, School of Medicine Wuhan University of Science and Technology Wuhan China
| | - Man Han
- Brain Science and Advanced Technology Institute, School of Medicine Wuhan University of Science and Technology Wuhan China
| | - Si‐ming Zhang
- Brain Science and Advanced Technology Institute, School of Medicine Wuhan University of Science and Technology Wuhan China
| | - Yi‐qi Chen
- Brain Science and Advanced Technology Institute, School of Medicine Wuhan University of Science and Technology Wuhan China
| | - Jia Zou
- Brain Science and Advanced Technology Institute, School of Medicine Wuhan University of Science and Technology Wuhan China
| | - Shu‐yuan Bai
- Brain Science and Advanced Technology Institute, School of Medicine Wuhan University of Science and Technology Wuhan China
| | - Gui‐rong Cheng
- Brain Science and Advanced Technology Institute, School of Medicine Wuhan University of Science and Technology Wuhan China
| | - Yan Zeng
- Brain Science and Advanced Technology Institute, School of Medicine Wuhan University of Science and Technology Wuhan China
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15
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Machine learning predicts translation initiation sites in neurologic diseases with nucleotide repeat expansions. PLoS One 2022; 17:e0256411. [PMID: 35648796 PMCID: PMC9159584 DOI: 10.1371/journal.pone.0256411] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 05/16/2022] [Indexed: 11/19/2022] Open
Abstract
A number of neurologic diseases associated with expanded nucleotide repeats, including an inherited form of amyotrophic lateral sclerosis, have an unconventional form of translation called repeat-associated non-AUG (RAN) translation. It has been speculated that the repeat regions in the RNA fold into secondary structures in a length-dependent manner, promoting RAN translation. Repeat protein products are translated, accumulate, and may contribute to disease pathogenesis. Nucleotides that flank the repeat region, especially ones closest to the initiation site, are believed to enhance translation initiation. A machine learning model has been published to help identify ATG and near-cognate translation initiation sites; however, this model has diminished predictive power due to its extensive feature selection and limited training data. Here, we overcome this limitation and increase prediction accuracy by the following: a) capture the effect of nucleotides most critical for translation initiation via feature reduction, b) implement an alternative machine learning algorithm better suited for limited data, c) build comprehensive and balanced training data (via sampling without replacement) that includes previously unavailable sequences, and d) split ATG and near-cognate translation initiation codon data to train two separate models. We also design a supplementary scoring system to provide an additional prognostic assessment of model predictions. The resultant models have high performance, with ~85-88% accuracy, exceeding that of the previously published model by >18%. The models presented here are used to identify translation initiation sites in genes associated with a number of neurologic repeat expansion disorders. The results confirm a number of sites of translation initiation upstream of the expanded repeats that have been found experimentally, and predict sites that are not yet established.
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Boivin M, Charlet-Berguerand N. Trinucleotide CGG Repeat Diseases: An Expanding Field of Polyglycine Proteins? Front Genet 2022; 13:843014. [PMID: 35295941 PMCID: PMC8918734 DOI: 10.3389/fgene.2022.843014] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/31/2022] [Indexed: 12/30/2022] Open
Abstract
Microsatellites are repeated DNA sequences of 3–6 nucleotides highly variable in length and sequence and that have important roles in genomes regulation and evolution. However, expansion of a subset of these microsatellites over a threshold size is responsible of more than 50 human genetic diseases. Interestingly, some of these disorders are caused by expansions of similar sequences, sizes and localizations and present striking similarities in clinical manifestations and histopathological features, which suggest a common mechanism of disease. Notably, five identical CGG repeat expansions, but located in different genes, are the causes of fragile X-associated tremor/ataxia syndrome (FXTAS), neuronal intranuclear inclusion disease (NIID), oculopharyngodistal myopathy type 1 to 3 (OPDM1-3) and oculopharyngeal myopathy with leukoencephalopathy (OPML), which are neuromuscular and neurodegenerative syndromes with overlapping symptoms and similar histopathological features, notably the presence of characteristic eosinophilic ubiquitin-positive intranuclear inclusions. In this review we summarize recent finding in neuronal intranuclear inclusion disease and FXTAS, where the causing CGG expansions were found to be embedded within small upstream ORFs (uORFs), resulting in their translation into novel proteins containing a stretch of polyglycine (polyG). Importantly, expression of these polyG proteins is toxic in animal models and is sufficient to reproduce the formation of ubiquitin-positive intranuclear inclusions. These data suggest the existence of a novel class of human genetic pathology, the polyG diseases, and question whether a similar mechanism may exist in other diseases, notably in OPDM and OPML.
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Zhang Y, Glineburg MR, Basrur V, Conlon K, Wright SE, Krans A, Hall DA, Todd PK. Mechanistic convergence across initiation sites for RAN translation in fragile X associated tremor ataxia syndrome. Hum Mol Genet 2022; 31:2317-2332. [PMID: 35137065 PMCID: PMC9307318 DOI: 10.1093/hmg/ddab353] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/30/2021] [Accepted: 12/06/2021] [Indexed: 11/13/2022] Open
Abstract
Repeat associated non-AUG (RAN) translation of CGG repeats in the 5'UTR of FMR1 produces toxic proteins that contribute to fragile X-associated tremor/ataxia syndrome (FXTAS) pathogenesis. The most abundant RAN product, FMRpolyG, initiates predominantly at an ACG upstream of the repeat. Accurate FMRpolyG measurements in FXTAS patients are lacking. We used data-dependent acquisition and parallel reaction monitoring (PRM) mass spectrometry coupled with stable isotope labeled standard peptides to identify signature FMRpolyG fragments in patient samples. Following immunoprecipitation, PRM detected FMRpolyG signature peptides in transfected cells, and FXTAS tissues and cells, but not in controls. We identified two amino-terminal peptides: an ACG-initiated Ac-MEAPLPGGVR and a GUG-initiated Ac-TEAPLPGGVR, as well as evidence for RAN translation initiation within the CGG repeat itself in two reading frames. Initiation at all sites increased following cellular stress, decreased following eIF1 overexpression and was eIF4A and M7G cap-dependent. These data demonstrate that FMRpolyG is quantifiable in human samples and FMR1 RAN translation initiates via similar mechanisms for near-cognate codons and within the repeat through processes dependent on available initiation factors and cellular environment.
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Affiliation(s)
- Yuan Zhang
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA,Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha 410008, China
| | - M Rebecca Glineburg
- To whom correspondence should be addressed at: Todd Lab (ATTN: Drs Glineburg and Todd), 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA. Tel: +1 7346155632; Fax: +1 7346479777; ;
| | | | - Kevin Conlon
- Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Shannon E Wright
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Deborah A Hall
- Department of Neurological Sciences, Rush University, Chicago, IL, USA
| | - Peter K Todd
- To whom correspondence should be addressed at: Todd Lab (ATTN: Drs Glineburg and Todd), 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA. Tel: +1 7346155632; Fax: +1 7346479777; ;
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Gall-Duncan T, Sato N, Yuen RKC, Pearson CE. Advancing genomic technologies and clinical awareness accelerates discovery of disease-associated tandem repeat sequences. Genome Res 2022; 32:1-27. [PMID: 34965938 PMCID: PMC8744678 DOI: 10.1101/gr.269530.120] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 11/29/2021] [Indexed: 11/25/2022]
Abstract
Expansions of gene-specific DNA tandem repeats (TRs), first described in 1991 as a disease-causing mutation in humans, are now known to cause >60 phenotypes, not just disease, and not only in humans. TRs are a common form of genetic variation with biological consequences, observed, so far, in humans, dogs, plants, oysters, and yeast. Repeat diseases show atypical clinical features, genetic anticipation, and multiple and partially penetrant phenotypes among family members. Discovery of disease-causing repeat expansion loci accelerated through technological advances in DNA sequencing and computational analyses. Between 2019 and 2021, 17 new disease-causing TR expansions were reported, totaling 63 TR loci (>69 diseases), with a likelihood of more discoveries, and in more organisms. Recent and historical lessons reveal that properly assessed clinical presentations, coupled with genetic and biological awareness, can guide discovery of disease-causing unstable TRs. We highlight critical but underrecognized aspects of TR mutations. Repeat motifs may not be present in current reference genomes but will be in forthcoming gapless long-read references. Repeat motif size can be a single nucleotide to kilobases/unit. At a given locus, repeat motif sequence purity can vary with consequence. Pathogenic repeats can be "insertions" within nonpathogenic TRs. Expansions, contractions, and somatic length variations of TRs can have clinical/biological consequences. TR instabilities occur in humans and other organisms. TRs can be epigenetically modified and/or chromosomal fragile sites. We discuss the expanding field of disease-associated TR instabilities, highlighting prospects, clinical and genetic clues, tools, and challenges for further discoveries of disease-causing TR instabilities and understanding their biological and pathological impacts-a vista that is about to expand.
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Affiliation(s)
- Terence Gall-Duncan
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Nozomu Sato
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
| | - Ryan K C Yuen
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Christopher E Pearson
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Fisher PR, Allan CY, Sanislav O, Atkinson A, Ngoei KRW, Kemp BE, Storey E, Loesch DZ, Annesley SJ. Relationships between Mitochondrial Function, AMPK, and TORC1 Signaling in Lymphoblasts with Premutation Alleles of the FMR1 Gene. Int J Mol Sci 2021; 22:10393. [PMID: 34638732 PMCID: PMC8508849 DOI: 10.3390/ijms221910393] [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: 08/31/2021] [Revised: 09/23/2021] [Accepted: 09/23/2021] [Indexed: 12/23/2022] Open
Abstract
The X-linked FMR1 gene contains a non-coding trinucleotide repeat in its 5' region that, in normal, healthy individuals contains 20-44 copies. Large expansions of this region (>200 copies) cause fragile X syndrome (FXS), but expansions of 55-199 copies (referred to as premutation alleles) predispose carriers to a neurodegenerative disease called fragile X-associated tremor/ataxia syndrome (FXTAS). The cytopathological mechanisms underlying FXTAS are poorly understood, but abnormalities in mitochondrial function are believed to play a role. We previously reported that lymphoblastoid cell lines (LCLs, or lymphoblasts) of premutation carriers have elevated mitochondrial respiratory activities. In the carriers, especially those not clinically affected with FXTAS, AMP-activated protein kinase (AMPK) activity was shown to be elevated. In the FXTAS patients, however, it was negatively correlated with brain white matter lesions, suggesting a protective role in the molecular mechanisms. Here, we report an enlarged and extended study of mitochondrial function and associated cellular stress-signaling pathways in lymphoblasts isolated from male and female premutation carriers, regardless of their clinical status, and healthy controls. The results confirmed the elevation of AMPK and mitochondrial respiratory activities and reduction in reactive O2 species (ROS) levels in premutation cells and revealed for the first time that target of rapamycin complex I (TORC1) activities are reduced. Extensive correlation, multiple regression, and principal components analysis revealed the best fitting statistical explanations of these changes in terms of the other variables measured. These suggested which variables might be the most "proximal" regulators of the others in the extensive network of known causal interactions amongst the measured parameters of mitochondrial function and cellular stress signaling. In the resulting model, the premutation alleles activate AMPK and inhibit both TORC1 and ROS production, the reduced TORC1 activity contributes to activation of AMPK and of nonmitochondrial metabolism, and the higher AMPK activity results in elevated catabolic metabolism, mitochondrial respiration, and ATP steady state levels. In addition, the results suggest a separate CGG repeat number-dependent elevation of TORC1 activity that is insufficient to overcome the inhibition of TORC1 in premutation cells but may presage the previously reported activation of TORC1 in FXS cells.
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Affiliation(s)
- Paul R. Fisher
- Department of Physiology Anatomy and Microbiology, La Trobe University, Bundoora, VIC 3086, Australia; (C.Y.A.); (O.S.); (S.J.A.)
| | - Claire Y. Allan
- Department of Physiology Anatomy and Microbiology, La Trobe University, Bundoora, VIC 3086, Australia; (C.Y.A.); (O.S.); (S.J.A.)
| | - Oana Sanislav
- Department of Physiology Anatomy and Microbiology, La Trobe University, Bundoora, VIC 3086, Australia; (C.Y.A.); (O.S.); (S.J.A.)
| | - Anna Atkinson
- School of Psychology and Public Health, La Trobe University, Bundoora, VIC 3086, Australia; (A.A.); (D.Z.L.)
| | - Kevin R. W. Ngoei
- St. Vincent’s Institute of Medical Research, Department of Medicine, University of Melbourne, Fitzroy, VIC 3065, Australia; (K.R.W.N.); (B.E.K.)
| | - Bruce E. Kemp
- St. Vincent’s Institute of Medical Research, Department of Medicine, University of Melbourne, Fitzroy, VIC 3065, Australia; (K.R.W.N.); (B.E.K.)
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3000, Australia
| | - Elsdon Storey
- Department of Medicine, Alfred Hospital Campus, Monash University, Commercial Road, Melbourne, VIC 3004, Australia;
| | - Danuta Z. Loesch
- School of Psychology and Public Health, La Trobe University, Bundoora, VIC 3086, Australia; (A.A.); (D.Z.L.)
| | - Sarah J. Annesley
- Department of Physiology Anatomy and Microbiology, La Trobe University, Bundoora, VIC 3086, Australia; (C.Y.A.); (O.S.); (S.J.A.)
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Zhao X, Usdin K. (Dys)function Follows Form: Nucleic Acid Structure, Repeat Expansion, and Disease Pathology in FMR1 Disorders. Int J Mol Sci 2021; 22:ijms22179167. [PMID: 34502075 PMCID: PMC8431139 DOI: 10.3390/ijms22179167] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 12/26/2022] Open
Abstract
Fragile X-related disorders (FXDs), also known as FMR1 disorders, are examples of repeat expansion diseases (REDs), clinical conditions that arise from an increase in the number of repeats in a disease-specific microsatellite. In the case of FXDs, the repeat unit is CGG/CCG and the repeat tract is located in the 5' UTR of the X-linked FMR1 gene. Expansion can result in neurodegeneration, ovarian dysfunction, or intellectual disability depending on the number of repeats in the expanded allele. A growing body of evidence suggests that the mutational mechanisms responsible for many REDs share several common features. It is also increasingly apparent that in some of these diseases the pathologic consequences of expansion may arise in similar ways. It has long been known that many of the disease-associated repeats form unusual DNA and RNA structures. This review will focus on what is known about these structures, the proteins with which they interact, and how they may be related to the causative mutation and disease pathology in the FMR1 disorders.
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Affiliation(s)
- Xiaonan Zhao
- Correspondence: (X.Z.); (K.U.); Tel.: +1-301-451-6322 (X.Z.); +1-301-496-2189 (K.U.)
| | - Karen Usdin
- Correspondence: (X.Z.); (K.U.); Tel.: +1-301-451-6322 (X.Z.); +1-301-496-2189 (K.U.)
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21
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Singh CR, Glineburg MR, Moore C, Tani N, Jaiswal R, Zou Y, Aube E, Gillaspie S, Thornton M, Cecil A, Hilgers M, Takasu A, Asano I, Asano M, Escalante CR, Nakamura A, Todd PK, Asano K. Human oncoprotein 5MP suppresses general and repeat-associated non-AUG translation via eIF3 by a common mechanism. Cell Rep 2021; 36:109376. [PMID: 34260931 PMCID: PMC8363759 DOI: 10.1016/j.celrep.2021.109376] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/11/2021] [Accepted: 06/17/2021] [Indexed: 11/15/2022] Open
Abstract
eIF5-mimic protein (5MP) is a translational regulatory protein that binds the small ribosomal subunit and modulates its activity. 5MP is proposed to reprogram non-AUG translation rates for oncogenes in cancer, but its role in controlling non-AUG initiated synthesis of deleterious repeat-peptide products, such as FMRpolyG observed in fragile-X-associated tremor ataxia syndrome (FXTAS), is unknown. Here, we show that 5MP can suppress both general and repeat-associated non-AUG (RAN) translation by a common mechanism in a manner dependent on its interaction with eIF3. Essentially, 5MP displaces eIF5 through the eIF3c subunit within the preinitiation complex (PIC), thereby increasing the accuracy of initiation. In Drosophila, 5MP/Kra represses neuronal toxicity and enhances the lifespan in an FXTAS disease model. These results implicate 5MP in protecting cells from unwanted byproducts of non-AUG translation in neurodegeneration.
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Affiliation(s)
- Chingakham Ranjit Singh
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | | | - Chelsea Moore
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Naoki Tani
- Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Rahul Jaiswal
- Department of Physiology and Biophysics, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, USA
| | - Ye Zou
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA
| | - Eric Aube
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Sarah Gillaspie
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Mackenzie Thornton
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Ariana Cecil
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Madelyn Hilgers
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Azuma Takasu
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Izumi Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Masayo Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | - Carlos R Escalante
- Department of Physiology and Biophysics, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, USA
| | - Akira Nakamura
- Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Ann Arbor VA Medical Center, Ann Arbor, MI 48105, USA
| | - Katsura Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, KS 66506, USA; Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan; Hiroshima Research Center for Healthy Aging, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan.
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22
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Shelly KE, Candelaria NR, Li Z, Allen EG, Jin P, Nelson DL. Ectopic expression of CGG-repeats alters ovarian response to gonadotropins and leads to infertility in a murine FMR1 premutation model. Hum Mol Genet 2021; 30:923-938. [PMID: 33856019 PMCID: PMC8165648 DOI: 10.1093/hmg/ddab083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 02/18/2021] [Accepted: 03/30/2021] [Indexed: 01/03/2023] Open
Abstract
Women heterozygous for an expansion of CGG repeats in the 5'UTR of FMR1 risk developing fragile X-associated primary ovarian insufficiency (FXPOI) and/or tremor and ataxia syndrome (FXTAS). We show that expanded CGGs, independent of FMR1, are sufficient to drive ovarian insufficiency and that expression of CGG-containing mRNAs alone or in conjunction with a polyglycine-containing peptide translated from these RNAs contribute to dysfunction. Heterozygous females from two mouse lines expressing either CGG RNA-only (RNA-only) or CGG RNA and the polyglycine product FMRpolyG (FMRpolyG+RNA) were used to assess ovarian function in aging animals. The expression of FMRpolyG+RNA led to early cessation of breeding, ovulation and transcriptomic changes affecting cholesterol and steroid hormone biosynthesis. Females expressing CGG RNA-only did not exhibit decreased progeny during natural breeding, but their ovarian transcriptomes were enriched for alterations in cholesterol and lipid biosynthesis. The enrichment of CGG RNA-only ovaries for differentially expressed genes related to cholesterol processing provided a link to the ovarian cysts observed in both CGG-expressing lines. Early changes in transcriptome profiles led us to measure ovarian function in prepubertal females that revealed deficiencies in ovulatory responses to gonadotropins. These include impairments in cumulus expansion and resumption of oocyte meiosis, as well as reduced ovulated oocyte number. Cumulatively, we demonstrated the sufficiency of ectopically expressed CGG repeats to lead to ovarian insufficiency and that co-expression of CGG-RNA and FMRpolyG lead to premature cessation of breeding. However, the expression of CGG RNA-alone was sufficient to lead to ovarian dysfunction by impairing responses to hormonal stimulation.
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Affiliation(s)
- Katharine E Shelly
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nicholes R Candelaria
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ziyi Li
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Emily G Allen
- Department of Human Genetics, Emory University, Atlanta, GA 30322, USA
| | - Peng Jin
- Department of Human Genetics, Emory University, Atlanta, GA 30322, USA
| | - David L Nelson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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Abstract
PURPOSE OF REVIEW The purpose of this paper is to review the prevalence, pathophysiology, and management of fragile X-associated tremor/ataxia syndrome (FXTAS). RECENT FINDINGS The pathophysiology of FXTAS involves ribonucleic acid (RNA) toxicity due to elevated levels of the premutation-expanded CGG (eoxycytidylate-deoxyguanylate-deoxyguanylate)-repeat FMR1 mRNA, which can sequester a variety of proteins important for neuronal function. A recent analysis of the inclusions in FXTAS demonstrates elevated levels of several proteins, including small ubiquitin-related modifiers 1/2 (SUMO1/2), that target molecules for the proteasome, suggesting that some aspect(s) of proteasomal function may be altered in FXTAS. Recent neuropathological studies show that Parkinson disease and Alzheimer disease can sometimes co-occur with FXTAS. Lewy bodies can be found in 10% of the brains of patients with FXTAS. Microbleeds and iron deposition are also common in the neuropathology, in addition to white matter disease (WMD) and atrophy. SUMMARY The premutation occurs in 1:200 females and 1:400 males. Penetrance for FXTAS increases with age, though lower in females (16%) compared to over 60% of males by age 70. To diagnose FXTAS, an MRI is essential to document the presence of WMD, a primary component of the diagnostic criteria. Pain can be a significant feature of FXTAS and is seen in approximately 50% of patients.
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Usdin K, Rodriguez-Revenga L, Willemsen R, Hukema R, Giulivi C. Editorial: Proceedings of the "Fourth International Conference of the FMR1 Premutation: Basic Mechanisms, Clinical Involvement and Therapy". Front Mol Biosci 2021; 8:671875. [PMID: 33987206 PMCID: PMC8111284 DOI: 10.3389/fmolb.2021.671875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 03/29/2021] [Indexed: 11/25/2022] Open
Affiliation(s)
- Karen Usdin
- Gene Structure and Disease Section, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Laia Rodriguez-Revenga
- Biochemistry and Molecular Genetics Department, Hospital Clinic of Barcelona and CIBER of Rare Diseases (CIBERER), Instituto de Salud Carlos III, Barcelona, Spain
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Renate Hukema
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States.,The MIND Institute, University of California, Davis Medical Center, Sacramento, CA, United States
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Glineburg MR, Zhang Y, Krans A, Tank EM, Barmada SJ, Todd PK. Enhanced detection of expanded repeat mRNA foci with hybridization chain reaction. Acta Neuropathol Commun 2021; 9:73. [PMID: 33892814 PMCID: PMC8063431 DOI: 10.1186/s40478-021-01169-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 03/27/2021] [Indexed: 12/17/2022] Open
Abstract
Transcribed nucleotide repeat expansions form detectable RNA foci in patient cells that contribute to disease pathogenesis. The most widely used method for detecting RNA foci, fluorescence in situ hybridization (FISH), is powerful but can suffer from issues related to signal above background. Here we developed a repeat-specific form of hybridization chain reaction (R-HCR) as an alternative method for detection of repeat RNA foci in two neurodegenerative disorders: C9orf72 associated ALS and frontotemporal dementia (C9 ALS/FTD) and Fragile X-associated tremor/ataxia syndrome. R-HCR to both G4C2 and CGG repeats exhibited comparable specificity but > 40 × sensitivity compared to FISH, with better detection of both nuclear and cytoplasmic foci in human C9 ALS/FTD fibroblasts, patient iPSC derived neurons, and patient brain samples. Using R-HCR, we observed that integrated stress response (ISR) activation significantly increased the number of endogenous G4C2 repeat RNA foci and triggered their selective nuclear accumulation without evidence of stress granule co-localization in patient fibroblasts and patient derived neurons. These data suggest that R-HCR can be a useful tool for tracking the behavior of repeat expansion mRNA in C9 ALS/FTD and other repeat expansion disorders.
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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] [Key Words] [MESH Headings] [Grants] [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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27
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Holm KN, Herren AW, Taylor SL, Randol JL, Kim K, Espinal G, Martiínez-Cerdeño V, Pessah IN, Hagerman RJ, Hagerman PJ. Human Cerebral Cortex Proteome of Fragile X-Associated Tremor/Ataxia Syndrome. Front Mol Biosci 2021; 7:600840. [PMID: 33585555 PMCID: PMC7879451 DOI: 10.3389/fmolb.2020.600840] [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: 08/31/2020] [Accepted: 11/27/2020] [Indexed: 01/10/2023] Open
Abstract
Background: Fragile X-associated tremor/ataxia syndrome (FXTAS) is an adult-onset neurodegenerative disorder associated with premutation CGG-repeat expansions (55–200 repeats) in the 5′ non-coding portion of the fragile X mental retardation 1 (FMR1) gene. Core features of FXTAS include progressive tremor/ataxia, cognitive decline, variable brain volume loss, and white matter disease. The principal histopathological feature of FXTAS is the presence of central nervous system (CNS) and non-CNS intranuclear inclusions. Objective: To further elucidate the molecular underpinnings of FXTAS through the proteomic characterization of human FXTAS cortexes. Results: Proteomic analysis of FXTAS brain cortical tissue (n = 8) identified minor differences in protein abundance compared to control brains (n = 6). Significant differences in FXTAS relative to control brain predominantly involved decreased abundance of proteins, with the greatest decreases observed for tenascin-C (TNC), cluster of differentiation 38 (CD38), and phosphoserine aminotransferase 1 (PSAT1); proteins typically increased in other neurodegenerative diseases. Proteins with the greatest increased abundance include potentially novel neurodegeneration-related proteins and small ubiquitin-like modifier 1/2 (SUMO1/2). The FMRpolyG peptide, proposed in models of FXTAS pathogenesis but only identified in trace amounts in the earlier study of FXTAS inclusions, was not identified in any of the FXTAS or control brains in the current study. Discussion: The observed proteomic shifts, while generally relatively modest, do show a bias toward decreased protein abundance with FXTAS. Such shifts in protein abundance also suggest altered RNA binding as well as loss of cell–cell adhesion/structural integrity. Unlike other neurodegenerative diseases, the proteome of end-stage FXTAS does not suggest a strong inflammation-mediated degenerative response.
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Affiliation(s)
- Katharine Nichole Holm
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Davis, CA, United States
| | - Anthony W Herren
- Mass Spectrometry Research Core, University of California Davis, Davis, CA, United States
| | - Sandra L Taylor
- Department of Public Health Sciences, Division of Biostatistics, University of California Davis School of Medicine, Davis, CA, United States
| | - Jamie L Randol
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Davis, CA, United States
| | - Kyoungmi Kim
- Department of Public Health Sciences, Division of Biostatistics, University of California Davis School of Medicine, Davis, CA, United States.,Medical Investigation of Neurodevelopmental Disorders Institute, University of California Davis School of Medicine, Davis, CA, United States
| | - Glenda Espinal
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Davis, CA, United States
| | - Verónica Martiínez-Cerdeño
- Medical Investigation of Neurodevelopmental Disorders Institute, University of California Davis School of Medicine, Davis, CA, United States.,Department of Pathology and Laboratory Medicine, University of California Davis School of Medicine, Davis, CA, United States
| | - Isaac N Pessah
- Medical Investigation of Neurodevelopmental Disorders Institute, University of California Davis School of Medicine, Davis, CA, United States.,Department of Molecular Biosciences, University of California Davis School of Veterinary Medicine, Davis, CA, United States
| | - Randi J Hagerman
- Medical Investigation of Neurodevelopmental Disorders Institute, University of California Davis School of Medicine, Davis, CA, United States.,Department of Pediatrics, University of California Davis School of Medicine, Davis, CA, United States
| | - Paul J Hagerman
- Department of Biochemistry and Molecular Medicine, University of California Davis School of Medicine, Davis, CA, United States.,Medical Investigation of Neurodevelopmental Disorders Institute, University of California Davis School of Medicine, Davis, CA, United States
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28
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Dijkstra AA, Haify SN, Verwey NA, Prins ND, van der Toorn EC, Rozemuller AJM, Bugiani M, den Dunnen WFA, Todd PK, Charlet-Berguerand N, Willemsen R, Hukema RK, Hoozemans JJM. Neuropathology of FMR1-premutation carriers presenting with dementia and neuropsychiatric symptoms. Brain Commun 2021; 3:fcab007. [PMID: 33709078 PMCID: PMC7936660 DOI: 10.1093/braincomms/fcab007] [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: 06/26/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 01/07/2023] Open
Abstract
CGG repeat expansions within the premutation range (55–200) of the FMR1 gene can lead to Fragile X-associated tremor/ataxia syndrome and Fragile X-associated neuropsychiatric disorders. These CGG repeats are translated into a toxic polyglycine-containing protein, FMRpolyG. Pathology of Fragile X-associated tremor/ataxia syndrome and Fragile X-associated neuropsychiatric disorders comprises FMRpolyG- and p62-positive intranuclear inclusions. Diagnosing a FMR1-premutation carrier remains challenging, as the clinical features overlap with other neurodegenerative diseases. Here, we describe two male cases with Fragile X-associated neuropsychiatric disorders-related symptoms and mild movement disturbances and novel pathological features that can attribute to the variable phenotype. Macroscopically, both donors did not show characteristic white matter lesions on MRI; however, vascular infarcts in cortical- and sub-cortical regions were identified. Immunohistochemistry analyses revealed a high number of FMRpolyG intranuclear inclusions throughout the brain, which were also positive for p62. Importantly, we identified a novel pathological vascular phenotype with inclusions present in pericytes and endothelial cells. Although these results need to be confirmed in more cases, we propose that these vascular lesions in the brain could contribute to the complex symptomology of FMR1-premutation carriers. Overall, our report suggests that Fragile X-associated tremor/ataxia syndrome and Fragile X-associated neuropsychiatric disorders may present diverse clinical involvements resembling other types of dementia, and in the absence of genetic testing, FMRpolyG can be used post-mortem to identify premutation carriers.
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Affiliation(s)
- Anke A Dijkstra
- Department of Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Saif N Haify
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Niek A Verwey
- Department of Neurology, Medisch Centrum Leeuwarden, Leeuwarden, The Netherlands
| | - Niels D Prins
- Department of Neurology, Alzheimer Center, VU University Medical Center, Amsterdam Neuroscience, The Netherlands.,Brain Research Center, Amsterdam, The Netherlands
| | | | - Annemieke J M Rozemuller
- Department of Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Marianna Bugiani
- Department of Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centre, Amsterdam, The Netherlands
| | - Wilfred F A den Dunnen
- Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, The Netherlands
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA.,Department of Veterans Affairs, Ann Arbor Healthcare System, Ann Arbor, MI, USA
| | - Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400, Illkirch, France
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Renate K Hukema
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands.,Department of Health Care Studies, Rotterdam University of Applied Sciences, Rotterdam, The Netherlands
| | - Jeroen J M Hoozemans
- Department of Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centre, Amsterdam, The Netherlands
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29
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Asamitsu S, Yabuki Y, Ikenoshita S, Kawakubo K, Kawasaki M, Usuki S, Nakayama Y, Adachi K, Kugoh H, Ishii K, Matsuura T, Nanba E, Sugiyama H, Fukunaga K, Shioda N. CGG repeat RNA G-quadruplexes interact with FMRpolyG to cause neuronal dysfunction in fragile X-related tremor/ataxia syndrome. SCIENCE ADVANCES 2021; 7:7/3/eabd9440. [PMID: 33523882 PMCID: PMC7806243 DOI: 10.1126/sciadv.abd9440] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 11/18/2020] [Indexed: 05/25/2023]
Abstract
Fragile X-related tremor/ataxia syndrome (FXTAS) is a neurodegenerative disease caused by CGG triplet repeat expansions in FMR1, which elicit repeat-associated non-AUG (RAN) translation and produce the toxic protein FMRpolyG. We show that FMRpolyG interacts with pathogenic CGG repeat-derived RNA G-quadruplexes (CGG-G4RNA), propagates cell to cell, and induces neuronal dysfunction. The FMRpolyG polyglycine domain has a prion-like property, preferentially binding to CGG-G4RNA. Treatment with 5-aminolevulinic acid, which is metabolized to protoporphyrin IX, inhibited RAN translation of FMRpolyG and CGG-G4RNA-induced FMRpolyG aggregation, ameliorating aberrant synaptic plasticity and behavior in FXTAS model mice. Thus, we present a novel therapeutic strategy to target G4RNA prionoids.
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Affiliation(s)
- Sefan Asamitsu
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan
| | - Yasushi Yabuki
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Susumu Ikenoshita
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Kosuke Kawakubo
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Moe Kawasaki
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Shingo Usuki
- Liaison Laboratory Research Promotion Center, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan
| | - Yuji Nakayama
- Division of Radioisotope Science, Research Initiative Center, Organization for Research Initiative and Promotion, Tottori University, Tottori, Japan
| | - Kaori Adachi
- Division of Genomic Science, Research Initiative Center, Organization for Research Initiative and Promotion, Tottori University, Tottori, Japan
| | - Hiroyuki Kugoh
- Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Tottori, Japan
- Chromosome Engineering Research Center, Tottori University, Tottori, Japan
| | - Kazuhiro Ishii
- Department of the Neurology, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Tohru Matsuura
- Division of Neurology, Department of Medicine, Jichi Medical University, Shimono, Japan
| | - Eiji Nanba
- Office for Research Strategy, Organization for Research Initiative and Promotion, Tottori University, Tottori, Japan
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Kohji Fukunaga
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Norifumi Shioda
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan.
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
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30
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Haify SN, Mankoe RSD, Boumeester V, van der Toorn EC, Verhagen RFM, Willemsen R, Hukema RK, Bosman LWJ. Lack of a Clear Behavioral Phenotype in an Inducible FXTAS Mouse Model Despite the Presence of Neuronal FMRpolyG-Positive Aggregates. Front Mol Biosci 2020; 7:599101. [PMID: 33381520 PMCID: PMC7768028 DOI: 10.3389/fmolb.2020.599101] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/23/2020] [Indexed: 11/25/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a rare neurodegenerative disorder caused by a 55–200 CGG repeat expansion in the 5′ untranslated region of the Fragile X Mental Retardation 1 (FMR1) gene. FXTAS is characterized by progressive cerebellar ataxia, Parkinsonism, intention tremors and cognitive decline. The main neuropathological hallmark of FXTAS is the presence of ubiquitin-positive intranuclear inclusions in neurons and astrocytes throughout the brain. The molecular pathology of FXTAS involves the presence of 2 to 8-fold elevated levels of FMR1 mRNA, and of a repeat-associated non-AUG (RAN) translated polyglycine peptide (FMRpolyG). Increased levels of FMR1 mRNA containing an expanded CGG repeat can result in cellular toxicity by an RNA gain-of-function mechanism. The increased levels of CGG repeat-expanded FMR1 transcripts may create RNA foci that sequester important cellular proteins, including RNA-binding proteins and FMRpolyG, in intranuclear inclusions. To date, it is unclear whether the FMRpolyG-positive intranuclear inclusions are a cause or a consequence of FXTAS disease pathology. In this report we studied the relation between the presence of neuronal intranuclear inclusions and behavioral deficits using an inducible mouse model for FXTAS. Neuronal intranuclear inclusions were observed 4 weeks after dox-induction. After 12 weeks, high numbers of FMRpolyG-positive intranuclear inclusions could be detected in the hippocampus and striatum, but no clear signs of behavioral deficits related to these specific brain regions were found. In conclusion, the observations in our inducible mouse model for FXTAS suggest a lack of correlation between the presence of intranuclear FMRpolyG-positive aggregates in brain regions and specific behavioral phenotypes.
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Affiliation(s)
- Saif N Haify
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Ruchira S D Mankoe
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands.,Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | | | - Rob F M Verhagen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Renate K Hukema
- Department of Clinical Genetics, Erasmus MC, Rotterdam, Netherlands.,Department of Health Care Studies, Rotterdam University of Applied Sciences, Rotterdam, Netherlands
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31
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Castro AF, Loureiro JR, Bessa J, Silveira I. Antisense Transcription across Nucleotide Repeat Expansions in Neurodegenerative and Neuromuscular Diseases: Progress and Mysteries. Genes (Basel) 2020; 11:E1418. [PMID: 33261024 PMCID: PMC7760973 DOI: 10.3390/genes11121418] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
Unstable repeat expansions and insertions cause more than 30 neurodegenerative and neuromuscular diseases. Remarkably, bidirectional transcription of repeat expansions has been identified in at least 14 of these diseases. More remarkably, a growing number of studies has been showing that both sense and antisense repeat RNAs are able to dysregulate important cellular pathways, contributing together to the observed clinical phenotype. Notably, antisense repeat RNAs from spinocerebellar ataxia type 7, myotonic dystrophy type 1, Huntington's disease and frontotemporal dementia/amyotrophic lateral sclerosis associated genes have been implicated in transcriptional regulation of sense gene expression, acting either at a transcriptional or posttranscriptional level. The recent evidence that antisense repeat RNAs could modulate gene expression broadens our understanding of the pathogenic pathways and adds more complexity to the development of therapeutic strategies for these disorders. In this review, we cover the amazing progress made in the understanding of the pathogenic mechanisms associated with repeat expansion neurodegenerative and neuromuscular diseases with a focus on the impact of antisense repeat transcription in the development of efficient therapies.
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Affiliation(s)
- Ana F. Castro
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (A.F.C.); (J.R.L.)
- IBMC-Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal;
- ICBAS, Universidade do Porto, 4050-313 Porto, Portugal
| | - Joana R. Loureiro
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (A.F.C.); (J.R.L.)
- IBMC-Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal;
| | - José Bessa
- IBMC-Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal;
- Vertebrate Development and Regeneration Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Isabel Silveira
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (A.F.C.); (J.R.L.)
- IBMC-Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal;
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32
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The Role of Alpha-Synuclein and Other Parkinson's Genes in Neurodevelopmental and Neurodegenerative Disorders. Int J Mol Sci 2020; 21:ijms21165724. [PMID: 32785033 PMCID: PMC7460874 DOI: 10.3390/ijms21165724] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 07/29/2020] [Accepted: 08/08/2020] [Indexed: 12/13/2022] Open
Abstract
Neurodevelopmental and late-onset neurodegenerative disorders present as separate entities that are clinically and neuropathologically quite distinct. However, recent evidence has highlighted surprising commonalities and converging features at the clinical, genomic, and molecular level between these two disease spectra. This is particularly striking in the context of autism spectrum disorder (ASD) and Parkinson's disease (PD). Genetic causes and risk factors play a central role in disease pathophysiology and enable the identification of overlapping mechanisms and pathways. Here, we focus on clinico-genetic studies of causal variants and overlapping clinical and cellular features of ASD and PD. Several genes and genomic regions were selected for our review, including SNCA (alpha-synuclein), PARK2 (parkin RBR E3 ubiquitin protein ligase), chromosome 22q11 deletion/DiGeorge region, and FMR1 (fragile X mental retardation 1) repeat expansion, which influence the development of both ASD and PD, with converging features related to synaptic function and neurogenesis. Both PD and ASD display alterations and impairments at the synaptic level, representing early and key disease phenotypes, which support the hypothesis of converging mechanisms between the two types of diseases. Therefore, understanding the underlying molecular mechanisms might inform on common targets and therapeutic approaches. We propose to re-conceptualize how we understand these disorders and provide a new angle into disease targets and mechanisms linking neurodevelopmental disorders and neurodegeneration.
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33
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Salcedo-Arellano MJ, Dufour B, McLennan Y, Martinez-Cerdeno V, Hagerman R. Fragile X syndrome and associated disorders: Clinical aspects and pathology. Neurobiol Dis 2020; 136:104740. [PMID: 31927143 PMCID: PMC7027994 DOI: 10.1016/j.nbd.2020.104740] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/17/2019] [Accepted: 01/08/2020] [Indexed: 12/23/2022] Open
Abstract
This review aims to assemble many years of research and clinical experience in the fields of neurodevelopment and neuroscience to present an up-to-date understanding of the clinical presentation, molecular and brain pathology associated with Fragile X syndrome, a neurodevelopmental condition that develops with the full mutation of the FMR1 gene, located in the q27.3 loci of the X chromosome, and Fragile X-associated tremor/ataxia syndrome a neurodegenerative disease experienced by aging premutation carriers of the FMR1 gene. It is important to understand that these two syndromes have a very distinct clinical and pathological presentation while sharing the same origin: the mutation of the FMR1 gene; revealing the complexity of expansion genetics.
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Affiliation(s)
- Maria Jimena Salcedo-Arellano
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA, USA; Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, Sacramento, CA, USA; Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, Sacramento, CA, USA; Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, USA.
| | - Brett Dufour
- Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, Sacramento, CA, USA; Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, USA
| | - Yingratana McLennan
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA, USA; Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, Sacramento, CA, USA; Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, Sacramento, CA, USA
| | - Veronica Martinez-Cerdeno
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, Sacramento, CA, USA; Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children Northern California, Sacramento, CA, USA; Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, USA
| | - Randi Hagerman
- Department of Pediatrics, University of California Davis School of Medicine, Sacramento, CA, USA; Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, Sacramento, CA, USA.
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34
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Rodriguez CM, Wright SE, Kearse MG, Haenfler JM, Flores BN, Liu Y, Ifrim MF, Glineburg MR, Krans A, Jafar-Nejad P, Sutton MA, Bassell GJ, Parent JM, Rigo F, Barmada SJ, Todd PK. A native function for RAN translation and CGG repeats in regulating fragile X protein synthesis. Nat Neurosci 2020; 23:386-397. [PMID: 32066985 PMCID: PMC7668390 DOI: 10.1038/s41593-020-0590-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 01/10/2020] [Indexed: 02/07/2023]
Abstract
Repeat-associated non-AUG-initiated translation of expanded CGG repeats (CGG RAN) from the FMR1 5'-leader produces toxic proteins that contribute to neurodegeneration in fragile X-associated tremor/ataxia syndrome. Here we describe how unexpanded CGG repeats and their translation play conserved roles in regulating fragile X protein (FMRP) synthesis. In neurons, CGG RAN acts as an inhibitory upstream open reading frame to suppress basal FMRP production. Activation of mGluR5 receptors enhances FMRP synthesis. This enhancement requires both the CGG repeat and CGG RAN initiation sites. Using non-cleaving antisense oligonucleotides (ASOs), we selectively blocked CGG RAN. This ASO blockade enhanced endogenous FMRP expression in human neurons. In human and rodent neurons, CGG RAN-blocking ASOs suppressed repeat toxicity and prolonged survival. These findings delineate a native function for CGG repeats and RAN translation in regulating basal and activity-dependent FMRP synthesis, and they demonstrate the therapeutic potential of modulating CGG RAN translation in fragile X-associated disorders.
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Affiliation(s)
- Caitlin M Rodriguez
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Shannon E Wright
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Michael G Kearse
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, Ohio State University, Columbus, OH, USA
| | - Jill M Haenfler
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Brittany N Flores
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Yu Liu
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Marius F Ifrim
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Mary R Glineburg
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
| | | | - Michael A Sutton
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Jack M Parent
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA, USA
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI, 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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35
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Suardi GAM, Haddad LA. FMRP ribonucleoprotein complexes and RNA homeostasis. ADVANCES IN GENETICS 2020; 105:95-136. [PMID: 32560791 DOI: 10.1016/bs.adgen.2020.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The Fragile Mental Retardation 1 gene (FMR1), at Xq27.3, encodes the fragile mental retardation protein (FMRP), and displays in its 5'-untranslated region a series of polymorphic CGG triplet repeats that may undergo dynamic mutation. Fragile X syndrome (FXS) is the leading cause of inherited intellectual disability among men, and is most frequently due to FMR1 full mutation and consequent transcription repression. FMR1 premutations may associate with at least two other clinical conditions, named fragile X-associated primary ovarian insufficiency (FXPOI) and tremor and ataxia syndrome (FXTAS). While FXPOI and FXTAS appear to be mediated by FMR1 mRNA accumulation, relative reduction of FMRP, and triplet repeat translation, FXS is due to the lack of the RNA-binding protein FMRP. Besides its function as mRNA translation repressor in neuronal and stem/progenitor cells, RNA editing roles have been assigned to FMRP. In this review, we provide a brief description of FMR1 transcribed microsatellite and associated clinical disorders, and discuss FMRP molecular roles in ribonucleoprotein complex assembly and trafficking, as well as aspects of RNA homeostasis affected in FXS cells.
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Affiliation(s)
- Gabriela Aparecida Marcondes Suardi
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Luciana Amaral Haddad
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
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36
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Sacino AN, Prokop S, Walsh MA, Adamson J, Subramony SH, Krans A, Todd PK, Giasson BI, Yachnis AT. Fragile X-associated tremor ataxia syndrome with co-occurrent progressive supranuclear palsy-like neuropathology. Acta Neuropathol Commun 2019; 7:158. [PMID: 31665069 PMCID: PMC6820960 DOI: 10.1186/s40478-019-0818-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 09/29/2019] [Indexed: 02/07/2023] Open
Abstract
Co-occurrence of multiple neuropathologic changes is a common phenomenon, most prominently seen in Alzheimer's disease (AD) and Parkinson's disease (PD), complicating clinical diagnosis and patient management. Reports of co-occurring pathological processes are emerging in the group of genetically defined repeat-associated non-AUG (RAN)-translation related diseases. Here we report a case of Fragile X-associated tremor-ataxia syndrome (FXTAS) with widespread and abundant nuclear inclusions of the RAN-translation related FMRpolyG-peptide. In addition, we describe prominent neuronal and glial tau pathology representing changes seen in progressive supranuclear palsy (PSP). The highest abundance of the respective pathological changes was seen in distinct brain regions indicating an incidental, rather than causal correlation.
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