1
|
Li XY, Lai H, Li X, Xu F, Song Y, Wang Z, Li Q, Lin R, Xu Z, Wang C. Genetic profiles of multiple system atrophy revealed by exome sequencing, long-read sequencing and spinocerebellar ataxia repeat expansion analysis. Eur J Neurol 2024:e16441. [PMID: 39152783 DOI: 10.1111/ene.16441] [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: 03/10/2024] [Revised: 06/10/2024] [Accepted: 07/30/2024] [Indexed: 08/19/2024]
Abstract
BACKGROUND AND PURPOSE Multiple system atrophy (MSA) is a progressive, adult-onset neurodegenerative disorder clinically characterized by combinations of autonomic failure, parkinsonism, cerebellar ataxia and pyramidal signs. Although a few genetic factors have been reported to contribute to the disease, its mutational profiles have not been systemically studied. METHODS To address the genetic profiles of clinically diagnosed MSA patients, exome sequencing and triplet repeat detection was conducted in 205 MSA patients, including one familial case. The pathogenicity of variants was determined according to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology guidelines. RESULTS In the familial patient, a novel heterozygous COQ2 pathogenic variant (p.Ala351Thr) was identified in the MSA pedigree. In the sporadic patients, 29 pathogenic variants were revealed in 21 genes, and the PARK7 p.Ala104Thr variant was significantly associated with MSA (p = 0.0018). Moreover, burden tests demonstrated that the pathogenic variants were enriched in cerebellar ataxia-related genes in patients. Furthermore, repeat expansion analyses revealed that two patients carried the pathogenic CAG repeat expansion in the CACNA1A gene (SCA6), one patient carried the (ACAGG)exp/(ACAGG)exp expansion in RFC1 and one carried the GAA-pure expansion in FGF14 gene. CONCLUSION In conclusion, a novel COQ2 pathogenic variant was identified in a familial MSA patient, and repeat expansions in CACNA1A, RFC1 and FGF14 gene were detected in four sporadic patients. Moreover, a PARK7 variant and the burden of pathogenic variants in cerebellar ataxia-related genes were associated with MSA.
Collapse
Affiliation(s)
- Xu-Ying Li
- Department of Neurology, Xuanwu Hospital of Capital Medical University, National Clinical Research Centre for Geriatric Diseases, Beijing, China
| | - Hong Lai
- Department of Neurology, Xuanwu Hospital of Capital Medical University, National Clinical Research Centre for Geriatric Diseases, Beijing, China
| | - Xian Li
- Department of Neurology, Xuanwu Hospital of Capital Medical University, National Clinical Research Centre for Geriatric Diseases, Beijing, China
| | - Fanxi Xu
- Department of Neurology, Xuanwu Hospital of Capital Medical University, National Clinical Research Centre for Geriatric Diseases, Beijing, China
| | - Yang Song
- Department of Neurology, Xuanwu Hospital of Capital Medical University, National Clinical Research Centre for Geriatric Diseases, Beijing, China
| | - Zhanjun Wang
- Department of Neurology, Xuanwu Hospital of Capital Medical University, National Clinical Research Centre for Geriatric Diseases, Beijing, China
| | - Qibin Li
- Shenzhen Clabee Biotechnology Incorporation, Shenzhen, Guangdong, China
| | - Ruichai Lin
- Shenzhen Clabee Biotechnology Incorporation, Shenzhen, Guangdong, China
| | - Zhiheng Xu
- Institute of Genetics and Developmental Biology Chinese Academy of Sciences, Beijing, China
| | - Chaodong Wang
- Department of Neurology, Xuanwu Hospital of Capital Medical University, National Clinical Research Centre for Geriatric Diseases, Beijing, China
| |
Collapse
|
2
|
Coulombe B, Chapleau A, Macintosh J, Durcan TM, Poitras C, Moursli YA, Faubert D, Pinard M, Bernard G. Towards a Treatment for Leukodystrophy Using Cell-Based Interception and Precision Medicine. Biomolecules 2024; 14:857. [PMID: 39062571 PMCID: PMC11274857 DOI: 10.3390/biom14070857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 07/12/2024] [Accepted: 07/14/2024] [Indexed: 07/28/2024] Open
Abstract
Cell-based interception and precision medicine is a novel approach aimed at improving healthcare through the early detection and treatment of diseased cells. Here, we describe our recent progress towards developing cell-based interception and precision medicine to detect, understand, and advance the development of novel therapeutic approaches through a single-cell omics and drug screening platform, as part of a multi-laboratory collaborative effort, for a group of neurodegenerative disorders named leukodystrophies. Our strategy aims at the identification of diseased cells as early as possible to intercept progression of the disease prior to severe clinical impairment and irreversible tissue damage.
Collapse
Affiliation(s)
- Benoit Coulombe
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; (C.P.); (Y.A.M.); (M.P.)
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3T 1A8, Canada
| | - Alexandra Chapleau
- Department of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montréal, QC H9X 3V9, Canada; (A.C.); (J.M.); (G.B.)
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
- The Neuro’s Early Drug Discovery Unit (EDDU), McGill University, Montréal, QC H9X 3V9, Canada;
| | - Julia Macintosh
- Department of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montréal, QC H9X 3V9, Canada; (A.C.); (J.M.); (G.B.)
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Thomas M. Durcan
- The Neuro’s Early Drug Discovery Unit (EDDU), McGill University, Montréal, QC H9X 3V9, Canada;
| | - Christian Poitras
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; (C.P.); (Y.A.M.); (M.P.)
| | - Yena A. Moursli
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; (C.P.); (Y.A.M.); (M.P.)
| | - Denis Faubert
- Mass Spectrometry and Proteomics Platform, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada;
| | - Maxime Pinard
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; (C.P.); (Y.A.M.); (M.P.)
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montréal, QC H9X 3V9, Canada; (A.C.); (J.M.); (G.B.)
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
- Department Specialized Medicine, Division of Medical Genetics, McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| |
Collapse
|
3
|
Moir RD, Merheb E, Chitu V, Richard Stanley E, Willis IM. Molecular basis of neurodegeneration in a mouse model of Polr3-related disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.12.571310. [PMID: 38168294 PMCID: PMC10760057 DOI: 10.1101/2023.12.12.571310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Pathogenic variants in subunits of RNA polymerase (Pol) III cause a spectrum of Polr3-related neurodegenerative diseases including 4H leukodystrophy. Disease onset occurs from infancy to early adulthood and is associated with a variable range and severity of neurological and non-neurological features. The molecular basis of Polr3-related disease pathogenesis is unknown. We developed a postnatal whole-body mouse model expressing pathogenic Polr3a mutations to examine the molecular mechanisms by which reduced Pol III transcription results primarily in central nervous system phenotypes. Polr3a mutant mice exhibit behavioral deficits, cerebral pathology and exocrine pancreatic atrophy. Transcriptome and immunohistochemistry analyses of cerebra during disease progression show a reduction in most Pol III transcripts, induction of innate immune and integrated stress responses and cell type-specific gene expression changes reflecting neuron and oligodendrocyte loss and microglial activation. Earlier in the disease when integrated stress and innate immune responses are minimally induced, mature tRNA sequencing revealed a global reduction in tRNA levels and an altered tRNA profile but no changes in other Pol III transcripts. Thus, changes in the size and/or composition of the tRNA pool have a causal role in disease initiation. Our findings reveal different tissue- and brain region-specific sensitivities to a defect in Pol III transcription.
Collapse
Affiliation(s)
- Robyn D. Moir
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| | - Emilio Merheb
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| | - Violeta Chitu
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| | - E. Richard Stanley
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| | - Ian M. Willis
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx NY 10461, USA
| |
Collapse
|
4
|
Haneda A, Hoots JK, Hagy HA, Lacy M. Case report: Neuropsychological assessment in a patient with 4H leukodystrophy. Clin Neuropsychol 2024; 38:1272-1289. [PMID: 37974060 DOI: 10.1080/13854046.2023.2279697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 10/31/2023] [Indexed: 11/19/2023]
Abstract
Objective: POLR3-HLD or 4H leukodystrophy is an autosomal recessive disorder characterized by hypomyelination, hypodontia, and hypogonadotropic hypogonadism, and caused by variants in POLR3A, POLR3B, POLR1C, or POLR3K genes. Neurological and non-neurological clinical features and disease severity vary. While previous studies reference variable cognition, this is the first report of 4H detailing a comprehensive neuropsychological assessment. Method: The current study presents a 20-year-old, English-speaking, right-handed, non-Hispanic White female with 12 years of education with genetically confirmed 4H POLR3B-related leukodystrophy without hormonal replacement treatment. Results: At age 4, developmental delays, ataxia, hearing loss, and abnormal dentition were present. Imaging, endocrinology, and neurologic examinations revealed hypomyelination, reduced cerebellar volume, delayed bone age density, osteopenia, and evidence of adrenarche without signs of true puberty. Neuropsychological assessment at age 20 revealed global cognitive impairment with intellectual, attention, verbal memory retrieval, construction, executive (e.g. processing speed, sustained attention) and math computation deficits, along with behavioral dysregulation. Conclusion: We present the first detailed neuropsychological assessment of a patient with 4H leukodystrophy. The neuropsychological assessment revealed cognitive and behavioral dysexecutive deficits aligning with hypomyelination observed on imaging. Further longitudinal studies are needed to shed light on the neurobehavioral presentation associated with this disorder to assist care providers, patients, and their families.
Collapse
Affiliation(s)
- Aya Haneda
- Department of Psychology, Roosevelt University, Chicago, IL, USA
- University of Chicago Medical Center, Department of Psychiatry and Behavioral Neuroscience, Chicago, IL, USA
| | - Jennifer K Hoots
- University of Chicago Medical Center, Department of Psychiatry and Behavioral Neuroscience, Chicago, IL, USA
- Department of Psychology, University of Illinois Chicago, Chicago, IL, USA
| | - Hannah A Hagy
- University of Chicago Medical Center, Department of Psychiatry and Behavioral Neuroscience, Chicago, IL, USA
- Loyola University, Chicago, IL, USA
| | - Maureen Lacy
- University of Chicago Medical Center, Department of Psychiatry and Behavioral Neuroscience, Chicago, IL, USA
| |
Collapse
|
5
|
Rey F, Esposito L, Maghraby E, Mauri A, Berardo C, Bonaventura E, Tonduti D, Carelli S, Cereda C. Role of epigenetics and alterations in RNA metabolism in leukodystrophies. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1854. [PMID: 38831585 DOI: 10.1002/wrna.1854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 06/05/2024]
Abstract
Leukodystrophies are a class of rare heterogeneous disorders which affect the white matter of the brain, ultimately leading to a disruption in brain development and a damaging effect on cognitive, motor and social-communicative development. These disorders present a great clinical heterogeneity, along with a phenotypic overlap and this could be partially due to contributions from environmental stimuli. It is in this context that there is a great need to investigate what other factors may contribute to both disease insurgence and phenotypical heterogeneity, and novel evidence are raising the attention toward the study of epigenetics and transcription mechanisms that can influence the disease phenotype beyond genetics. Modulation in the epigenetics machinery including histone modifications, DNA methylation and non-coding RNAs dysregulation, could be crucial players in the development of these disorders, and moreover an aberrant RNA maturation process has been linked to leukodystrophies. Here, we provide an overview of these mechanisms hoping to supply a closer step toward the analysis of leukodystrophies not only as genetically determined but also with an added level of complexity where epigenetic dysregulation is of key relevance. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNA RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development.
Collapse
Affiliation(s)
- Federica Rey
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Letizia Esposito
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Erika Maghraby
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
- Department of Biology and Biotechnology "L. Spallanzani" (DBB), University of Pavia, Pavia, Italy
| | - Alessia Mauri
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Clarissa Berardo
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Eleonora Bonaventura
- Unit of Pediatric Neurology, COALA Center for Diagnosis and Treatment of Leukodystrophies, V. Buzzi Children's Hospital, Milan, Italy
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Davide Tonduti
- Unit of Pediatric Neurology, COALA Center for Diagnosis and Treatment of Leukodystrophies, V. Buzzi Children's Hospital, Milan, Italy
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Stephana Carelli
- Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi," Department of Biomedical and Clinical Sciences, University of Milano, Milan, Italy
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| | - Cristina Cereda
- Center of Functional Genomics and Rare Diseases, Department of Pediatrics, Buzzi Children's Hospital, Milan, Italy
| |
Collapse
|
6
|
Coulombe B, Durcan TM, Bernard G, Moursli A, Poitras C, Faubert D, Pinard M. The 37TrillionCells initiative for improving global healthcare via cell-based interception and precision medicine: focus on neurodegenerative diseases. Mol Brain 2024; 17:18. [PMID: 38605409 PMCID: PMC11007934 DOI: 10.1186/s13041-024-01088-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 03/15/2024] [Indexed: 04/13/2024] Open
Abstract
One of the main burdens in the treatment of diseases is imputable to the delay between the appearance of molecular dysfunctions in the first affected disease cells and their presence in sufficient number for detection in specific tissues or organs. This delay obviously plays in favor of disease progression to an extent that makes efficient treatments difficult, as they arrive too late. The development of a novel medical strategy, termed cell-based interception and precision medicine, seeks to identify dysfunctional cells early, when tissue damages are not apparent and symptoms not yet present, and develop therapies to treat diseases early. Central to this strategy is the use of single-cell technologies that allow detection of molecular changes in cells at the time of phenotypical bifurcation from health to disease. In this article we describe a general procedure to support such an approach applied to neurodegenerative disorders. This procedure combines four components directed towards highly complementary objectives: 1) a high-performance single-cell proteomics (SCP) method (Detect), 2) the development of disease experimental cell models and predictive computational models of cell trajectories (Understand), 3) the discovery of specific targets and personalized therapies (Cure), and 4) the creation of a community of collaborating laboratories to accelerate the development of this novel medical paradigm (Collaborate). A global initiative named 37TrillionCells (37TC) was launched to advance the development of cell-based interception and precision medicine.
Collapse
Affiliation(s)
- Benoit Coulombe
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montreal, QC, H2W 1R7, Canada.
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, QC, Canada.
| | - Thomas M Durcan
- The Neuro's Early Drug Discovery Unit (EDDU), McGill University, Montreal, Canada
| | - Geneviève Bernard
- Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, Canada
- Department Specialized Medicine, Division of Medical Genetics, McGill University Health Centre, Montreal, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Asmae Moursli
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montreal, QC, H2W 1R7, Canada
| | - Christian Poitras
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montreal, QC, H2W 1R7, Canada
| | - Denis Faubert
- Mass Spectrometry and Proteomics Platform, Institut de Recherches Cliniques de Montréal, Montreal, QC, H2W1R7, Canada
| | - Maxime Pinard
- Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montreal, QC, H2W 1R7, Canada
| |
Collapse
|
7
|
Scaravilli A, Tranfa M, Pontillo G, Brais B, De Michele G, La Piana R, Saccà F, Santorelli FM, Synofzik M, Brunetti A, Cocozza S. A Review of Brain and Pituitary Gland MRI Findings in Patients with Ataxia and Hypogonadism. CEREBELLUM (LONDON, ENGLAND) 2024; 23:757-774. [PMID: 37155088 DOI: 10.1007/s12311-023-01562-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/26/2023] [Indexed: 05/10/2023]
Abstract
The association of cerebellar ataxia and hypogonadism occurs in a heterogeneous group of disorders, caused by different genetic mutations often associated with a recessive inheritance. In these patients, magnetic resonance imaging (MRI) plays a pivotal role in the diagnostic workflow, with a variable involvement of the cerebellar cortex, alone or in combination with other brain structures. Neuroimaging involvement of the pituitary gland is also variable. Here, we provide an overview of the main clinical and conventional brain and pituitary gland MRI imaging findings of the most common genetic mutations associated with the clinical phenotype of ataxia and hypogonadism, with the aim of helping neuroradiologists in the identification of these disorders.
Collapse
Affiliation(s)
- Alessandra Scaravilli
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy
| | - Mario Tranfa
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy
| | - Giuseppe Pontillo
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy
- Department of Electrical Engineering and Information Technology (DIETI), University of Naples "Federico II", Naples, Italy
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, Montreal, Canada
| | - Giovanna De Michele
- Department of Neurosciences and Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Naples, Italy
| | - Roberta La Piana
- Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, Montreal, Canada
| | - Francesco Saccà
- Department of Neurosciences and Reproductive and Odontostomatological Sciences, University of Naples "Federico II", Naples, Italy
| | | | - Matthis Synofzik
- German Center for Neurodegenerative Diseases (DZNE), Tubingen, Germany
- Division Translational Genomics of Neurodegenerative Diseases, Center for Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Otfried-Müller-Strasse 27, 72076, Tubingen, Germany
| | - Arturo Brunetti
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy
| | - Sirio Cocozza
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131, Naples, Italy.
| |
Collapse
|
8
|
Ruan DD, Ruan XL, Wang RL, Lin XF, Zhang YP, Lin B, Li SJ, Wu M, Chen Q, Zhang JH, Cheng Q, Zhang YW, Lin F, Luo JW, Zheng Z, Li YF. Clinical phenotype and genetic function analysis of a family with hypomyelinating leukodystrophy-7 caused by POLR3A mutation. Sci Rep 2024; 14:7638. [PMID: 38561452 PMCID: PMC10985069 DOI: 10.1038/s41598-024-58452-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 03/29/2024] [Indexed: 04/04/2024] Open
Abstract
Hypomyelinating leukodystrophy (HLD) is a rare genetic heterogeneous disease that can affect myelin development in the central nervous system. This study aims to analyze the clinical phenotype and genetic function of a family with HLD-7 caused by POLR3A mutation. The proband (IV6) in this family mainly showed progressive cognitive decline, dentin dysplasia, and hypogonadotropic hypogonadism. Her three old brothers (IV1, IV2, and IV4) also had different degrees of ataxia, dystonia, or dysarthria besides the aforementioned manifestations. Their brain magnetic resonance imaging showed bilateral periventricular white matter atrophy, brain atrophy, and corpus callosum atrophy and thinning. The proband and her two living brothers (IV2 and IV4) were detected to carry a homozygous mutation of the POLR3A (NM_007055.4) gene c. 2300G > T (p.Cys767Phe), and her consanguineous married parents (III1 and III2) were p.Cys767Phe heterozygous carriers. In the constructed POLR3A wild-type and p.Cys767Phe mutant cells, it was seen that overexpression of wild-type POLR3A protein significantly enhanced Pol III transcription of 5S rRNA and tRNA Leu-CAA. However, although the mutant POLR3A protein overexpression was increased compared to the wild-type protein overexpression, it did not show the expected further enhancement of Pol III function. On the contrary, Pol III transcription function was frustrated (POLR3A, BC200, and tRNA Leu-CAA expression decreased), and MBP and 18S rRNA expressions were decreased. This study indicates that the POLR3A p.Cys767Phe variant caused increased expression of mutated POLR3A protein and abnormal expression of Pol III transcripts, and the mutant POLR3A protein function was abnormal.
Collapse
Affiliation(s)
- Dan-Dan Ruan
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Xing-Lin Ruan
- Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, 350001, China
| | - Ruo-Li Wang
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
- Fujian Provincial Key Laboratory of Emergency Medicine, Fujian Provincial Institute of Emergency Medicine, Fujian Emergency Medical Center, Fuzhou, 350001, China
| | - Xin-Fu Lin
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
- Pediatrics Department, Fujian Provincial Hospital, Fuzhou, 350001, China
| | - Yan-Ping Zhang
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Bin Lin
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Shi-Jie Li
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Min Wu
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Qian Chen
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Jian-Hui Zhang
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Qiong Cheng
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
- Department of Neurology, Fujian Provincial Hospital, Fuzhou, 350001, China
| | - Yi-Wu Zhang
- Department of Neurology, Youxi County General Hospital, Sanming, 365100, China
| | - Fan Lin
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China.
- Department of Geriatric Medicine, Fujian Provincial Center for Geriatrics, Fujian Provincial Hospital, Fuzhou, 350001, China.
| | - Jie-Wei Luo
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China.
| | - Zheng Zheng
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China.
- Department of Neurology, Fujian Provincial Hospital, Fuzhou, 350001, China.
| | - Yun-Fei Li
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China.
- Department of Neurology, Fujian Provincial Hospital, Fuzhou, 350001, China.
| |
Collapse
|
9
|
Khan A, Al Shamsi B, Al Shehhi M, Kashgari AA, Al Balushi A, Al Dihan FA, Alghamdi MA, Manal A, González‐Álvarez AC, Arold ST, Eyaid W. Further delineation of Wiedemann-Rautenstrauch syndrome linked with POLR3A. Mol Genet Genomic Med 2024; 12:e2274. [PMID: 38348603 PMCID: PMC10958179 DOI: 10.1002/mgg3.2274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/03/2023] [Accepted: 08/08/2023] [Indexed: 03/23/2024] Open
Abstract
Wiedemann-Rautenstrauch Syndrome (WRS; MIM 264090) is an extremely rare and highly heterogeneous syndrome that is inherited in a recessive fashion. The patients have hallmark features such as prenatal and postnatal growth retardation, short stature, a progeroid appearance, hypotonia, facial dysmorphology, hypomyelination leukodystrophy, and mental impairment. Biallelic disease-causing variants in the RNA polymerase III subunit A (POLR3A) have been associated with WRS. Here, we report the first identified cases of WRS syndrome with novel phenotypes in three consanguineous families (two Omani and one Saudi) characterized by biallelic variants in POLR3A. Using whole-exome sequencing, we identified one novel homozygous missense variant (NM_007055: c.2456C>T; p. Pro819Leu) in two Omani families and one novel homozygous variant (c.1895G>T; p Cys632Phe) in Saudi family that segregates with the disease in the POLR3A gene. In silico homology modeling of wild-type and mutated proteins revealed a substantial change in the structure and stability of both proteins, demonstrating a possible effect on function. By identifying the homozygous variants in the exon 14 and 18 of the POLR3A gene, our findings will contribute to a better understanding of the phenotype-genotype relationship and molecular etiology of WRS syndrome.
Collapse
Affiliation(s)
- Amjad Khan
- Faculty of Science, Department of Biological Sciences (Zoology)University of Lakki MarwatLakki MarwatPakistan
- Institute for Medical Genetics and Applied GenomicsUniversity of TübingenTübingenGermany
- Alexander von Humboldt Fellowship FoundationBerlinGermany
| | - Bushra Al Shamsi
- National Genetics CenterThe Royal Hospital, Ministry of HealthMuscatSultanate of Oman
- Child Health DepartmentThe Royal Hospital, Ministry of HealthMuscatSultanate of Oman
| | - Maryam Al Shehhi
- National Genetics CenterThe Royal Hospital, Ministry of HealthMuscatSultanate of Oman
| | - Amna A. Kashgari
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre (KAIMRC)King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard‐Health Affairs (MNGHA)RiyadhSaudi Arabia
- King Abdullah Specialized Children's Hospital (KASCH)Ministry of National Guard Health AffairsRiyadhSaudi Arabia
| | - Aaisha Al Balushi
- National Genetics CenterThe Royal Hospital, Ministry of HealthMuscatSultanate of Oman
- Child Health DepartmentThe Royal Hospital, Ministry of HealthMuscatSultanate of Oman
| | - Fahad A. Al Dihan
- College of MedicineKing Saud Bin Abdulaziz University for Health SciencesRiyadhSaudi Arabia
| | - Mohannad A. Alghamdi
- College of MedicineKing Saud Bin Abdulaziz University for Health SciencesRiyadhSaudi Arabia
| | - Abothnain Manal
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre (KAIMRC)King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard‐Health Affairs (MNGHA)RiyadhSaudi Arabia
- King Abdullah Specialized Children's Hospital (KASCH)Ministry of National Guard Health AffairsRiyadhSaudi Arabia
| | - Ana C. González‐Álvarez
- Bioscience Program, Bioengineering Program, Biological and Environmental Science and Engineering DivisionKing Abdullah University of Science and Technology (KAUST)ThuwalKingdom of Saudi Arabia
- Computational Biology Research CenterKing Abdullah University of Science and TechnologyThuwalKingdom of Saudi Arabia
| | - Stefan T. Arold
- Bioscience Program, Bioengineering Program, Biological and Environmental Science and Engineering DivisionKing Abdullah University of Science and Technology (KAUST)ThuwalKingdom of Saudi Arabia
- Computational Biology Research CenterKing Abdullah University of Science and TechnologyThuwalKingdom of Saudi Arabia
- Centre de Biologie Structurale (CBS), INSERM, CNRSUniversité de MontpellierMontpellierFrance
| | - Wafaa Eyaid
- Genetics Division, Department of Pediatrics, King Abdullah International Medical Research Centre (KAIMRC)King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, Ministry of National Guard‐Health Affairs (MNGHA)RiyadhSaudi Arabia
- King Abdullah Specialized Children's Hospital (KASCH)Ministry of National Guard Health AffairsRiyadhSaudi Arabia
| |
Collapse
|
10
|
Iwata-Otsubo A, Skraban CM, Yoshimura A, Sakata T, Alves CAP, Fiordaliso SK, Kuroda Y, Vengoechea J, Grochowsky A, Ernste P, Lulis L, Nesbitt A, Tayoun AA, Gray C, Towne MC, Radtke K, Normand EA, Rhodes L, Seiler C, Shirahige K, Izumi K. Biallelic variants in GTF3C5, a regulator of RNA polymerase III-mediated transcription, cause a multisystem developmental disorder. Hum Genet 2024; 143:437-453. [PMID: 38520561 DOI: 10.1007/s00439-024-02656-3] [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: 11/22/2023] [Accepted: 02/13/2024] [Indexed: 03/25/2024]
Abstract
General transcription factor IIIC subunit 5 (GTF3C5) encodes transcription factor IIIC63 (TFIIIC63). It binds to DNA to recruit another transcription factor, TFIIIB, and RNA polymerase III (Pol III) to mediate the transcription of small noncoding RNAs, such as tRNAs. Here, we report four individuals from three families presenting with a multisystem developmental disorder phenotype with biallelic variants in GTF3C5. The overlapping features include growth retardation, developmental delay, intellectual disability, dental anomalies, cerebellar malformations, delayed bone age, skeletal anomalies, and facial dysmorphism. Using lymphoblastoid cell lines (LCLs) from two affected individuals, we observed a reduction in TFIIIC63 protein levels compared to control LCLs. Genome binding of TFIIIC63 protein is also reduced in LCL from one of the affected individuals. Additionally, approximately 40% of Pol III binding regions exhibited reduction in the level of Pol III occupancy in the mutant genome relative to the control, while approximately 54% of target regions showed comparable levels of Pol III occupancy between the two, indicating partial impairment of Pol III occupancy in the mutant genome. Yeasts with subject-specific variants showed temperature sensitivity and impaired growth, supporting the notion that the identified variants have deleterious effects. gtf3c5 mutant zebrafish showed developmental defects, including a smaller body, head, and eyes. Taken together, our data show that GTF3C5 plays an important role in embryonic development, and that biallelic variants in this gene cause a multisystem developmental disorder. Our study adds GTF3C5-related disorder to the growing list of genetic disorders associated with Pol III transcription machinery.
Collapse
Affiliation(s)
- Aiko Iwata-Otsubo
- Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
- Department of Pathology, University of Michigan, 2800 Plymouth Rd, Ann Arbor, MI, 48109, USA.
| | - Cara M Skraban
- Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Pediatrics, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Atsunori Yoshimura
- Laboratory of Genome Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, 113-0032, Japan
| | - Toyonori Sakata
- Laboratory of Genome Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, 113-0032, Japan
| | - Cesar Augusto P Alves
- Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Sarah K Fiordaliso
- Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Yukiko Kuroda
- Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Jaime Vengoechea
- Department of Human Genetics, Emory University, Atlanta, GA, 30322, USA
| | - Angela Grochowsky
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Paige Ernste
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- Invitae, San Francisco, CA, 94103, USA
| | - Lauren Lulis
- Division of Genomic Diagnostics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Addie Nesbitt
- Division of Genomic Diagnostics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Veritas Genetics, Danvers, MA, 01923, USA
| | - Ahmad Abou Tayoun
- Division of Genomic Diagnostics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Genomics Center of Excellence, Al Jalila Children's Specialty Hospital, Dubai Health, Center for Genomic Discovery, Mohammed Bin Rashid University, Dubai Health, UAE
| | - Christopher Gray
- Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | | | | | | | | | - Christoph Seiler
- Zebrafish Core, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Katsuhiko Shirahige
- Laboratory of Genome Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, 113-0032, Japan
| | - Kosuke Izumi
- Division of Human Genetics/Roberts Individualized Medical Genetics Center, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
- Department of Pediatrics, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Laboratory of Rare Disease Research, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, 113-0032, Japan.
- Division of Genetics and Metabolism, Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390-8573, USA.
| |
Collapse
|
11
|
Mattijssen S, Kerkhofs K, Stephen J, Yang A, Han CG, Tadafumi Y, Iben JR, Mishra S, Sakhawala RM, Ranjan A, Gowda M, Gahl WA, Gu S, Malicdan MC, Maraia RJ. A POLR3B-variant reveals a Pol III transcriptome response dependent on La protein/SSB. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.05.577363. [PMID: 38410490 PMCID: PMC10896340 DOI: 10.1101/2024.02.05.577363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
RNA polymerase III (Pol III, POLR3) synthesizes tRNAs and other small non-coding RNAs. Human POLR3 pathogenic variants cause a range of developmental disorders, recapitulated in part by mouse models, yet some aspects of POLR3 deficiency have not been explored. We characterized a human POLR3B:c.1625A>G;p.(Asn542Ser) disease variant that was found to cause mis-splicing of POLR3B. Genome-edited POLR3B1625A>G HEK293 cells acquired the mis-splicing with decreases in multiple POLR3 subunits and TFIIIB, although display auto-upregulation of the Pol III termination-reinitiation subunit POLR3E. La protein was increased relative to its abundant pre-tRNA ligands which bind via their U(n)U-3'-termini. Assays for cellular transcription revealed greater deficiencies for tRNA genes bearing terminators comprised of 4Ts than of ≥5Ts. La-knockdown decreased Pol III ncRNA expression unlinked to RNA stability. Consistent with these effects, small-RNAseq showed that POLR3B1625A>G and patient fibroblasts express more tRNA fragments (tRFs) derived from pre-tRNA 3'-trailers (tRF-1) than from mature-tRFs, and higher levels of multiple miRNAs, relative to control cells. The data indicate that decreased levels of Pol III transcripts can lead to functional excess of La protein which reshapes small ncRNA profiles revealing new depth in the Pol III system. Finally, patient cell RNA analysis uncovered a strategy for tRF-1/tRF-3 as POLR3-deficiency biomarkers.
Collapse
Affiliation(s)
- Sandy Mattijssen
- Section on Molecular and Cell Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Kyra Kerkhofs
- Section on Molecular and Cell Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Joshi Stephen
- Section of Human Biochemical Genetics, Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Acong Yang
- RNA Biology Laboratory, National Cancer Institute, Frederick, MD, 21702 USA
| | - Chen G. Han
- Section of Human Biochemical Genetics, Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - Yokoyama Tadafumi
- Section of Human Biochemical Genetics, Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - James R. Iben
- Molecular Genetics Core, NICHD, NIH, Bethesda, MD 20892, USA
| | - Saurabh Mishra
- Section on Molecular and Cell Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Rima M. Sakhawala
- Section on Molecular and Cell Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Amitabh Ranjan
- Section on Molecular and Cell Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Mamatha Gowda
- Department of Obstetrics & Gynaecology, Jawaharlal Institute of Post-Graduate Medical Education and Research, Puducherry, India
| | - William A. Gahl
- Section of Human Biochemical Genetics, Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
- NIH Undiagnosed Diseases Program, NIH, Bethesda, MD 20892, USA
| | - Shuo Gu
- RNA Biology Laboratory, National Cancer Institute, Frederick, MD, 21702 USA
| | - May C. Malicdan
- Section of Human Biochemical Genetics, Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
- NIH Undiagnosed Diseases Program, NIH, Bethesda, MD 20892, USA
| | - Richard J. Maraia
- Section on Molecular and Cell Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| |
Collapse
|
12
|
Kovalskaia VA, Kungurtseva AL, Bostanova FM, Vasiliev PA, Tabakov VY, Orlova MD, Povolotskaya IS, Novoselova OG, Bikanov RA, Akhyamova MA, Tikhonovich YV, Popovich AV, Vitebskaya AV, Dadali EL, Ryzhkova OP. The Genetic Basis of the First Patient with Wiedemann-Rautenstrauch Syndrome in the Russian Federation. Genes (Basel) 2024; 15:180. [PMID: 38397171 PMCID: PMC10887809 DOI: 10.3390/genes15020180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/15/2024] [Accepted: 01/18/2024] [Indexed: 02/25/2024] Open
Abstract
Bi-allelic pathogenic variations within POLR3A have been associated with a spectrum of hereditary disorders. Among these, a less frequently observed condition is Wiedemann-Rautenstrauch syndrome (WRS), also known as neonatal progeroid syndrome. This syndrome typically manifests neonatally and is characterized by growth retardation, evident generalized lipodystrophy with distinctively localized fat accumulations, sparse scalp hair, and atypical facial features. Our objective was to elucidate the underlying molecular mechanisms of Wiedemann-Rautenstrauch syndrome (WRS). In this study, we present a clinical case of a 7-year-old female patient diagnosed with WRS. Utilizing whole-exome sequencing (WES), we identified a novel missense variant c.3677T>C (p.Leu1226Pro) in the POLR3A gene (NM_007055.4) alongside two cis intronic variants c.1909+22G>A and c.3337-11T>C. Via the analysis of mRNA derived from fibroblasts, we reconfirmed the splicing-affecting nature of the c.3337-11T>C variant. Furthermore, our investigation led to the reclassification of the c.3677T>C (p.Leu1226Pro) variant as a likely pathogenic variant. Therefore, this is the first case demonstrating the molecular genetics of a patient with Wiedemann-Rautenstrauch syndrome from the Russian Federation. A limited number of clinical cases have been documented until this moment; therefore, broadening the linkage between phenotype and molecular changes in the POLR3A gene will significantly contribute to the comprehensive understanding of the molecular basis of POLR3A-related disorders.
Collapse
Affiliation(s)
| | - Anastasiia L. Kungurtseva
- Pediatric Endocrinology Department, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia; (A.L.K.)
| | | | - Peter A. Vasiliev
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (V.A.K.)
| | | | - Mariia D. Orlova
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (V.A.K.)
| | | | | | | | | | - Yulia V. Tikhonovich
- Pediatric Endocrinology Department, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia; (A.L.K.)
| | - Anastasiia V. Popovich
- Pediatric Endocrinology Department, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia; (A.L.K.)
| | - Alisa V. Vitebskaya
- Pediatric Endocrinology Department, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia; (A.L.K.)
| | - Elena L. Dadali
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (V.A.K.)
| | - Oxana P. Ryzhkova
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (V.A.K.)
| |
Collapse
|
13
|
Michell-Robinson MA, Watt KEN, Grouza V, Macintosh J, Pinard M, Tuznik M, Chen X, Darbelli L, Wu CL, Perrier S, Chitsaz D, Uccelli NA, Liu H, Cox TC, Müller CW, Kennedy TE, Coulombe B, Rudko DA, Trainor PA, Bernard G. Hypomyelination, hypodontia and craniofacial abnormalities in a Polr3b mouse model of leukodystrophy. Brain 2023; 146:5070-5085. [PMID: 37635302 PMCID: PMC10690025 DOI: 10.1093/brain/awad249] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 06/23/2023] [Accepted: 07/06/2023] [Indexed: 08/29/2023] Open
Abstract
RNA polymerase III (Pol III)-related hypomyelinating leukodystrophy (POLR3-HLD), also known as 4H leukodystrophy, is a severe neurodegenerative disease characterized by the cardinal features of hypomyelination, hypodontia and hypogonadotropic hypogonadism. POLR3-HLD is caused by biallelic pathogenic variants in genes encoding Pol III subunits. While approximately half of all patients carry mutations in POLR3B encoding the RNA polymerase III subunit B, there is no in vivo model of leukodystrophy based on mutation of this Pol III subunit. Here, we determined the impact of POLR3BΔ10 (Δ10) on Pol III in human cells and developed and characterized an inducible/conditional mouse model of leukodystrophy using the orthologous Δ10 mutation in mice. The molecular mechanism of Pol III dysfunction was determined in human cells by affinity purification-mass spectrometry and western blot. Postnatal induction with tamoxifen induced expression of the orthologous Δ10 hypomorph in triple transgenic Pdgfrα-Cre/ERT; R26-Stopfl-EYFP; Polr3bfl mice. CNS and non-CNS features were characterized using a variety of techniques including microCT, ex vivo MRI, immunofluorescence, immunohistochemistry, spectral confocal reflectance microscopy and western blot. Lineage tracing and time series analysis of oligodendrocyte subpopulation dynamics based on co-labelling with lineage-specific and/or proliferation markers were performed. Proteomics suggested that Δ10 causes a Pol III assembly defect, while western blots demonstrated reduced POLR3BΔ10 expression in the cytoplasm and nucleus in human cells. In mice, postnatal Pdgfrα-dependent expression of the orthologous murine mutant protein resulted in recessive phenotypes including severe hypomyelination leading to ataxia, tremor, seizures and limited survival, as well as hypodontia and craniofacial abnormalities. Hypomyelination was confirmed and characterized using classic methods to quantify myelin components such as myelin basic protein and lipids, results which agreed with those produced using modern methods to quantify myelin based on the physical properties of myelin membranes. Lineage tracing uncovered the underlying mechanism for the hypomyelinating phenotype: defective oligodendrocyte precursor proliferation and differentiation resulted in a failure to produce an adequate number of mature oligodendrocytes during postnatal myelinogenesis. In summary, we characterized the Polr3bΔ10 mutation and developed an animal model that recapitulates features of POLR3-HLD caused by POLR3B mutations, shedding light on disease pathogenesis, and opening the door to the development of therapeutic interventions.
Collapse
Affiliation(s)
- Mackenzie A Michell-Robinson
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Kristin E N Watt
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Vladimir Grouza
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, QC H3A 2B4, Canada
| | - Julia Macintosh
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Maxime Pinard
- Translational Proteomics Research Unit, Montreal Clinical Research Institute, Montréal, QC H2W 1R7, Canada
| | - Marius Tuznik
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, QC H3A 2B4, Canada
| | - Xiaoru Chen
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Lama Darbelli
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Chia-Lun Wu
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Stefanie Perrier
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| | - Daryan Chitsaz
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
| | - Nonthué A Uccelli
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
| | - Hanwen Liu
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, QC H3A 2B4, Canada
| | - Timothy C Cox
- Department of Oral and Craniofacial Sciences, School of Dentistry, and Pediatrics, School of Medicine, University of Missouri – Kansas City, Kansas City, MO 64108, USA
| | - Christoph W Müller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Timothy E Kennedy
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
| | - Benoit Coulombe
- Translational Proteomics Research Unit, Montreal Clinical Research Institute, Montréal, QC H2W 1R7, Canada
- Department of Biochemistry and Molecular Medicine, University of Montréal, Montréal, QC H3C 3J7, Canada
| | - David A Rudko
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, QC H3A 2B4, Canada
- Department of Biomedical Engineering, McGill University, Montréal, QC H3A 2B4, Canada
| | - Paul A Trainor
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
- Department of Anatomy and Cell Biology, The University of Kansas School of Medicine, Kansas City, KS 66160, USA
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC H3A 1A1, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC H4A 3J1, Canada
- Department of Pediatrics, McGill University, Montréal, QC H4A 3J1, Canada
- Department of Human Genetics, McGill University, Montréal, QC H4A 0C7, Canada
- Department of Specialized Medicine, Division of Medical Genetics, Montreal Children’s Hospital and McGill University Health Centre, Montréal, QC H4A 3J1, Canada
| |
Collapse
|
14
|
Macintosh J, Perrier S, Pinard M, Tran LT, Guerrero K, Prasad C, Prasad AN, Pastinen T, Thiffault I, Coulombe B, Bernard G. Biallelic pathogenic variants in POLR3D alter tRNA transcription and cause a hypomyelinating leukodystrophy: A case report. Front Neurol 2023; 14:1254140. [PMID: 37915380 PMCID: PMC10616956 DOI: 10.3389/fneur.2023.1254140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/28/2023] [Indexed: 11/03/2023] Open
Abstract
RNA polymerase III-related leukodystrophy (POLR3-related leukodystrophy) is a rare, genetically determined hypomyelinating disease arising from biallelic pathogenic variants in genes encoding subunits of RNA polymerase III (Pol III). Here, we describe the first reported case of POLR3-related leukodystrophy caused by biallelic pathogenic variants in POLR3D, encoding the RPC4 subunit of Pol III. The individual, a female, demonstrated delays in walking and expressive and receptive language as a child and later cognitively plateaued. Additional neurological features included cerebellar signs (e.g., dysarthria, ataxia, and intention tremor) and dysphagia, while non-neurological features included hypodontia, hypogonadotropic hypogonadism, and dysmorphic facial features. Her MRI was notable for diffuse hypomyelination with myelin preservation of early myelinating structures, characteristic of POLR3-related leukodystrophy. Exome sequencing revealed the biallelic variants in POLR3D, a missense variant (c.541C > T, p.P181S) and an intronic splice site variant (c.656-6G > A, p.?). Functional studies of the patient's fibroblasts demonstrated significantly decreased RNA-level expression of POLR3D, along with reduced expression of other Pol III subunit genes. Notably, Pol III transcription was also shown to be aberrant, with a significant decrease in 7SK RNA and several distinct tRNA genes analyzed. Affinity purification coupled to mass spectrometry of the POLR3D p.P181S variant showed normal assembly of Pol III subunits yet altered interaction of Pol III with the PAQosome chaperone complex, indicating the missense variant is likely to alter complex maturation. This work identifies biallelic pathogenic variants in POLR3D as a novel genetic cause of POLR3-related leukodystrophy, expanding the molecular spectrum associated with this disease, and proposes altered tRNA homeostasis as a factor in the underlying biology of this hypomyelinating disorder.
Collapse
Affiliation(s)
- Julia Macintosh
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Stefanie Perrier
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Maxime Pinard
- Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada
| | - Luan T. Tran
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Kether Guerrero
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Chitra Prasad
- Department of Pediatrics, London Health Sciences Center and Western University, London, ON, Canada
- Medical Genetics Program of Southwestern Ontario, London Health Sciences Center, London, ON, Canada
- Children’s Health Research Institute, London, ON, Canada
| | - Asuri N. Prasad
- Department of Pediatrics, London Health Sciences Center and Western University, London, ON, Canada
- Children’s Health Research Institute, London, ON, Canada
| | - Tomi Pastinen
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO, United States
- University of Missouri Kansas City School of Medicine, Kansas City, MO, United States
- Department of Pediatrics, Children's Mercy Hospital, Kansas City, MO, United States
| | - Isabelle Thiffault
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO, United States
- University of Missouri Kansas City School of Medicine, Kansas City, MO, United States
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital, Kansas City, MO, United States
| | - Benoit Coulombe
- Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada
- Département de Biochimie et Médecine Moléculaire, Faculté de Médecine, Université de Montréal, Montreal, QC, Canada
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Centre, Montreal, QC, Canada
| |
Collapse
|
15
|
Mirchi A, Guay SP, Tran LT, Wolf NI, Vanderver A, Brais B, Sylvain M, Pohl D, Rossignol E, Saito M, Moutton S, González-Gutiérrez-Solana L, Thiffault I, Kruer MC, Moron DG, Kauffman M, Goizet C, Sztriha L, Glamuzina E, Melançon SB, Naidu S, Retrouvey JM, Lacombe S, Bernardino-Cuesta B, De Bie I, Bernard G. Craniofacial features of POLR3-related leukodystrophy caused by biallelic variants in POLR3A, POLR3B and POLR1C. J Med Genet 2023; 60:1026-1034. [PMID: 37197783 PMCID: PMC10579516 DOI: 10.1136/jmg-2023-109223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/16/2023] [Indexed: 05/19/2023]
Abstract
BACKGROUND RNA polymerase III-related or 4H leukodystrophy (POLR3-HLD) is an autosomal recessive hypomyelinating leukodystrophy characterized by neurological dysfunction, hypodontia and hypogonadotropic hypogonadism. The disease is caused by biallelic pathogenic variants in POLR3A, POLR3B, POLR1C or POLR3K. Craniofacial abnormalities reminiscent of Treacher Collins syndrome have been originally described in patients with POLR3-HLD caused by biallelic pathogenic variants in POLR1C. To date, no published studies have appraised in detail the craniofacial features of patients with POLR3-HLD. In this work, the specific craniofacial characteristics of patients with POLR3-HLD associated with biallelic pathogenic variants in POLR3A, POLR3B and POLR1C are described. METHODS The craniofacial features of 31 patients with POLR3-HLD were evaluated, and potential genotype-phenotype associations were evaluated. RESULTS Various craniofacial abnormalities were recognized in this patient cohort, with each individual presenting at least one craniofacial abnormality. The most frequently identified features included a flat midface (61.3%), a smooth philtrum (58.0%) and a pointed chin (51.6%). In patients with POLR3B biallelic variants, a thin upper lip was frequent. Craniofacial anomalies involving the forehead were most commonly associated with biallelic variants in POLR3A and POLR3B while a higher proportion of patients with POLR1C biallelic variants demonstrated bitemporal narrowing. CONCLUSION Through this study, we demonstrated that craniofacial abnormalities are common in patients with POLR3-HLD. This report describes in detail the dysmorphic features of POLR3-HLD associated with biallelic variants in POLR3A, POLR3B and POLR1C.
Collapse
Affiliation(s)
- Amytice Mirchi
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Pediatrics, McGill University, Montreal, Quebec, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Simon-Pierre Guay
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Quebec, Canada
| | - Luan T Tran
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Nicole I Wolf
- Department of Child Neurology, Amsterdam Leukodystrophy Center, Emma Children's Hospital, Amsterdam University Medical Centers, and Amsterdam Neuroscience, Cellular & Molecular Mechanisms, Vrije Universiteit, Amsterdam, Netherlands
| | - Adeline Vanderver
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Bernard Brais
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Montreal Neurological Institute, Montreal, Quebec, Canada
| | - Michel Sylvain
- Centre Mère Enfant, CHU de Québec, Québec City, Quebec, Canada
| | - Daniela Pohl
- Division of Neurology, Children's Hospital of Eastern Ontario, University of Ottawa, Ottawa, Ontario, Canada
| | - Elsa Rossignol
- Departments of Neurosciences and Pediatrics, CHU-Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Michael Saito
- Department of Pediatrics, University of California Riverside School of Medicine, Riverside Medical Clinic, Riverside, California, USA
| | - Sebastien Moutton
- Centre Pluridisciplinaire de Diagnostic PréNatal, MSPBordeaux Bagatelle, Talence, France
| | - Luis González-Gutiérrez-Solana
- Sección de Neuropediatría, Hospital Infantil Universitario Niño Jesús, Madrid, España; Grupo Clínico Vinculado al Centro de Investigación Biomédica en Red para Enfermedades Raras (CIBERER) GCV14/ER/6, Hospital Infantil Universitario Nino Jesus, Madrid, Spain
| | - Isabelle Thiffault
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, Missouri, USA
- University of Missouri Kansas City School of Medicine, Kansas City, Missouri, USA
| | - Michael C Kruer
- Departments of Child Health, Neurology, and Cellular & Molecular Medicine and Program in Genetics, University of Arizona College of Medicine, Phoenix, Arizona, USA
- Programs in Neuroscience and Molecular & Cellular Biology, School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, Arizona, USA
| | - Dolores Gonzales Moron
- Neurogenetics Unit, Department of Neurology, Hospital JM Ramos Mejia, ADC, Buenos Aires, Argentina
| | - Marcelo Kauffman
- Neurogenetics Unit, Department of Neurology, Hospital JM Ramos Mejia and CONICET-Universidad Austral, Buenos Aires, Argentina
| | - Cyril Goizet
- Centre de Référence Neurogénétique, Service de Génétique Médicale, Bordeaux University Hospital, CHU Bordeaux, Bordeaux, France
- NRGEN team, INCIA, CNRS UMR 5287, University of Bordeaux, Bordeaux, France
| | - László Sztriha
- Department of Paediatrics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Emma Glamuzina
- Adult and Paediatric National Metabolic Service, Starship Children's Hospital, Auckland, Te Whatu Ora, New Zealand
| | - Serge B Melançon
- Department of Medical Genetics, McGill University Health Centre, Montreal Children's Hospital, Montreal, Quebec, Canada
| | - Sakkubai Naidu
- Department of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Jean-Marc Retrouvey
- Department of Orthodontics, University of Missouri, Kansas City, Missouri, USA
| | - Suzanne Lacombe
- Department of Orthodontics, University of Missouri, Kansas City, Missouri, USA
| | | | - Isabelle De Bie
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Quebec, Canada
- Department of Laboratory Medicine, McGill University Health Centre, Montreal, Quebec, Canada
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
- Department of Pediatrics, McGill University, Montreal, Quebec, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Quebec, Canada
| |
Collapse
|
16
|
M Borella LF, Pereira DA, Reis F. Neuroimaging of POLR3B-related Hypomyelinating Leukodystrophy. Neurol India 2023; 71:1098-1099. [PMID: 37929490 DOI: 10.4103/0028-3886.388056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Affiliation(s)
- Luiz F M Borella
- Department of Radiology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Danilo A Pereira
- Department of Human Reproduction and Childhood, Pontifical Catholic University of São Paulo (PUC-SP), Sorocaba, SP, Brazil
| | - Fabiano Reis
- Department of Radiology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| |
Collapse
|
17
|
Hamdan Z, Alasmar D. Uncertain significance mutation in the POLR3B gene in a Syrian boy with leukodystrophy: a case report. Ann Med Surg (Lond) 2023; 85:4126-4130. [PMID: 37554900 PMCID: PMC10406027 DOI: 10.1097/ms9.0000000000001033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 06/20/2023] [Indexed: 08/10/2023] Open
Abstract
UNLABELLED 4H leukodystrophy, one of the POLR3-related leukodystrophy, is a rare hereditary brain white matter disease with characteristic clinical presentation and imaging findings. Hypomyelination, hypodontia, and hypogonadotropic hypogonadism is mainly presented in patients with 4H leukodystrophy. CASE PRESENTATION A 4-year-old boy presented in the neurologic clinic with delayed psychomotor development and progressive neurologic symptoms that started from the age of 20 months. Physical examination revealed ataxic features and a global development delay. The MRI was significant for hypomyelination. The most common causes of leukodystrophy were rolled out. He was referred to an inherited metabolic disease specialist under suspect of inborn metabolic errors because of laboratory analysis, which showed elevated levels of lactic acid, pyruvate, 4-Hydroxy-Phenylactic acid, 3-Hydroxy propionic acid, and decreased levels of PCO2, HCO3, total CO2, 25-Hydroxyvitamin D. These results were unspecific and mitochondrial disease was highly suspected. However, the genetic study was requested to get a defined diagnosis and treatment; the whole exon sequencing result showed a homozygous variant of uncertain significance mutation; related to an amino acid change from Ile to Thr at position 1002 in the POLR3B gene, which helped us to reveal the final diagnosis, and the genetic counseling were recommended for the next pregnancies. CONCLUSION POLR3-related Leukodystrophy is a very rare disease. The early diagnosis should be raised depending on clinical history and MRI findings after other conditions were rolled out, and the confirmed diagnosis depends on the genetic study.
Collapse
Affiliation(s)
| | - Diana Alasmar
- Pediatric Department, Damascus University Damascus, Syria
| |
Collapse
|
18
|
Macintosh J, Michell-Robinson M, Chen X, Bernard G. Decreased RNA polymerase III subunit expression leads to defects in oligodendrocyte development. Front Neurosci 2023; 17:1167047. [PMID: 37179550 PMCID: PMC10167296 DOI: 10.3389/fnins.2023.1167047] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 03/31/2023] [Indexed: 05/15/2023] Open
Abstract
Introduction RNA polymerase III (Pol III) is a critical enzymatic complex tasked with the transcription of ubiquitous non-coding RNAs including 5S rRNA and all tRNA genes. Despite the constitutive nature of this enzyme, hypomorphic biallelic pathogenic variants in genes encoding subunits of Pol III lead to tissue-specific features and cause a hypomyelinating leukodystrophy, characterized by a severe and permanent deficit in myelin. The pathophysiological mechanisms in POLR3- related leukodystrophy and specifically, how reduced Pol III function impacts oligodendrocyte development to account for the devastating hypomyelination seen in the disease, remain poorly understood. Methods In this study, we characterize how reducing endogenous transcript levels of leukodystrophy-associated Pol III subunits affects oligodendrocyte maturation at the level of their migration, proliferation, differentiation, and myelination. Results Our results show that decreasing Pol III expression altered the proliferation rate of oligodendrocyte precursor cells but had no impact on migration. Additionally, reducing Pol III activity impaired the differentiation of these precursor cells into mature oligodendrocytes, evident at both the level of OL-lineage marker expression and on morphological assessment, with Pol III knockdown cells displaying a drastically more immature branching complexity. Myelination was hindered in the Pol III knockdown cells, as determined in both organotypic shiverer slice cultures and co-cultures with nanofibers. Analysis of Pol III transcriptional activity revealed a decrease in the expression of distinct tRNAs, which was significant in the siPolr3a condition. Discussion In turn, our findings provide insight into the role of Pol III in oligodendrocyte development and shed light on the pathophysiological mechanisms of hypomyelination in POLR3-related leukodystrophy.
Collapse
Affiliation(s)
- Julia Macintosh
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Mackenzie Michell-Robinson
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Xiaoru Chen
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada
| |
Collapse
|
19
|
Perrier S, Guerrero K, Tran LT, Michell-Robinson MA, Legault G, Brais B, Sylvain M, Dorman J, Demos M, Köhler W, Pastinen T, Thiffault I, Bernard G. Solving inherited white matter disorder etiologies in the neurology clinic: Challenges and lessons learned using next-generation sequencing. Front Neurol 2023; 14:1148377. [PMID: 37077564 PMCID: PMC10108901 DOI: 10.3389/fneur.2023.1148377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 02/23/2023] [Indexed: 04/05/2023] Open
Abstract
IntroductionRare neurodevelopmental disorders, including inherited white matter disorders or leukodystrophies, often present a diagnostic challenge on a genetic level given the large number of causal genes associated with a range of disease subtypes. This study aims to demonstrate the challenges and lessons learned in the genetic investigations of leukodystrophies through presentation of a series of cases solved using exome or genome sequencing.MethodsEach of the six patients had a leukodystrophy associated with hypomyelination or delayed myelination on MRI, and inconclusive clinical diagnostic genetic testing results. We performed next generation sequencing (case-based exome or genome sequencing) to further investigate the genetic cause of disease.ResultsFollowing different lines of investigation, molecular diagnoses were obtained for each case, with patients harboring pathogenic variants in a range of genes including TMEM106B, GJA1, AGA, POLR3A, and TUBB4A. We describe the lessons learned in reaching the genetic diagnosis, including the importance of (a) utilizing proper multi-gene panels in clinical testing, (b) assessing the reliability of biochemical assays in supporting diagnoses, and (c) understanding the limitations of exome sequencing methods in regard to CNV detection and region coverage in GC-rich areas.DiscussionThis study illustrates the importance of applying a collaborative diagnostic approach by combining detailed phenotyping data and metabolic results from the clinical environment with advanced next generation sequencing analysis techniques from the research environment to increase the diagnostic yield in patients with genetically unresolved leukodystrophies.
Collapse
Affiliation(s)
- Stefanie Perrier
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Kether Guerrero
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Luan T. Tran
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Mackenzie A. Michell-Robinson
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Geneviève Legault
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
| | - Bernard Brais
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Michel Sylvain
- Division of Pediatric Neurology, Centre Mère-Enfant Soleil du CHU de Québec - Université Laval, Québec City, QC, Canada
| | - James Dorman
- John H. Stroger Jr. Hospital of Cook County, Chicago, IL, United States
- Department of Neurological Sciences, Rush Medical College, Chicago, IL, United States
| | - Michelle Demos
- Division of Neurology, Department of Pediatrics, University of British Columbia, BC Children's Hospital, Vancouver, BC, Canada
| | - Wolfgang Köhler
- Leukodystrophy Center, University of Leipzig Medical Center, Leipzig, Germany
| | - Tomi Pastinen
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO, United States
- University of Missouri Kansas City School of Medicine, Kansas City, MO, United States
| | - Isabelle Thiffault
- Genomic Medicine Center, Children's Mercy Hospital, Kansas City, MO, United States
- University of Missouri Kansas City School of Medicine, Kansas City, MO, United States
- Department of Pathology and Laboratory Medicine, Children's Mercy Hospital, Kansas City, MO, United States
- Isabelle Thiffault
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Pediatrics, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada
- *Correspondence: Geneviève Bernard
| |
Collapse
|
20
|
Moon B, Kim M, Kim HJ, Cho JS, Son HJ, Lim BC, Kim KJ, Chae JH, Kim SY. Biallelic POLR3A variants cause Wiedemann-Rautenstrauch syndrome with atypical brain involvement. Clin Exp Pediatr 2023; 66:142-144. [PMID: 36596744 PMCID: PMC9989718 DOI: 10.3345/cep.2022.01144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/07/2022] [Indexed: 12/31/2022] Open
Affiliation(s)
- Byungseung Moon
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea
| | - Minhye Kim
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea
| | - Hye Jin Kim
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea
| | - Jae So Cho
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea
| | - Hey Joon Son
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea
| | - Byung Chan Lim
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea
| | - Ki Joong Kim
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea
| | - Jong Hee Chae
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea.,Department of Genomic Medicine, Seoul National University Hospital, Seoul, Korea
| | - Soo Yeon Kim
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Korea.,Department of Genomic Medicine, Seoul National University Hospital, Seoul, Korea
| |
Collapse
|
21
|
Watt KE, Macintosh J, Bernard G, Trainor PA. RNA Polymerases I and III in development and disease. Semin Cell Dev Biol 2023; 136:49-63. [PMID: 35422389 PMCID: PMC9550887 DOI: 10.1016/j.semcdb.2022.03.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/18/2022] [Accepted: 03/21/2022] [Indexed: 12/18/2022]
Abstract
Ribosomes are macromolecular machines that are globally required for the translation of all proteins in all cells. Ribosome biogenesis, which is essential for cell growth, proliferation and survival, commences with transcription of a variety of RNAs by RNA Polymerases I and III. RNA Polymerase I (Pol I) transcribes ribosomal RNA (rRNA), while RNA Polymerase III (Pol III) transcribes 5S ribosomal RNA and transfer RNAs (tRNA) in addition to a wide variety of small non-coding RNAs. Interestingly, despite their global importance, disruptions in Pol I and Pol III function result in tissue-specific developmental disorders, with craniofacial anomalies and leukodystrophy/neurodegenerative disease being among the most prevalent. Furthermore, pathogenic variants in genes encoding subunits shared between Pol I and Pol III give rise to distinct syndromes depending on whether Pol I or Pol III function is disrupted. In this review, we discuss the global roles of Pol I and III transcription, the consequences of disruptions in Pol I and III transcription, disorders arising from pathogenic variants in Pol I and Pol III subunits, and mechanisms underpinning their tissue-specific phenotypes.
Collapse
Affiliation(s)
- Kristin En Watt
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Julia Macintosh
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada; Departments of Pediatrics and Human Genetics, McGill University, Montreal, QC, Canada; Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada.
| | - Paul A Trainor
- Stowers Institute for Medical Research, Kansas City, MO, USA; Department of Anatomy & Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA.
| |
Collapse
|
22
|
Zhang X, Fang B, Huang YF. Transcription factor binding sites are frequently under accelerated evolution in primates. Nat Commun 2023; 14:783. [PMID: 36774380 PMCID: PMC9922303 DOI: 10.1038/s41467-023-36421-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 01/31/2023] [Indexed: 02/13/2023] Open
Abstract
Recent comparative genomic studies have identified many human accelerated elements (HARs) with elevated substitution rates in the human lineage. However, it remains unknown to what extent transcription factor binding sites (TFBSs) are under accelerated evolution in humans and other primates. Here, we introduce two pooling-based phylogenetic methods with dramatically enhanced sensitivity to examine accelerated evolution in TFBSs. Using these new methods, we show that more than 6000 TFBSs annotated in the human genome have experienced accelerated evolution in Hominini, apes, and Old World monkeys. Although these TFBSs individually show relatively weak signals of accelerated evolution, they collectively are more abundant than HARs. Also, we show that accelerated evolution in Pol III binding sites may be driven by lineage-specific positive selection, whereas accelerated evolution in other TFBSs might be driven by nonadaptive evolutionary forces. Finally, the accelerated TFBSs are enriched around developmental genes, suggesting that accelerated evolution in TFBSs may drive the divergence of developmental processes between primates.
Collapse
Affiliation(s)
- Xinru Zhang
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA. .,Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, 16802, USA. .,Bioinformatics and Genomics Graduate Program, Pennsylvania State University, University Park, PA, 16802, USA.
| | - Bohao Fang
- Department of Organismic and Evolutionary Biology and the Museum of Comparative Zoology, Harvard University, Boston, MA, 02135, USA
| | - Yi-Fei Huang
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA. .,Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, 16802, USA.
| |
Collapse
|
23
|
Zea Vera A, Bruce A, Larsh TR, Jordan Z, Brüggemann N, Westenberger A, Espay AJ, Gilbert DL, Wu SW. Spectrum of Pediatric to Early Adulthood POLR3A-Associated Movement Disorders. Mov Disord Clin Pract 2023; 10:316-322. [PMID: 36825045 PMCID: PMC9941928 DOI: 10.1002/mdc3.13635] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/14/2022] [Accepted: 11/23/2022] [Indexed: 12/12/2022] Open
Abstract
Background POLR3A pathogenic variants are associated with hypomyelination, hypodontia, hypogonadism, and movement disorders. Cases We describe the range of movement disorders seen in six patients (four female, two male) with POLR3A variants [three novel (c.2214del, c.3775G>A, c.3905G>T) and six previously reported (c.760C>T, c.1771-7C>G, c.1909+22G>A, c.2005C>T, c.2422C>T, c.3337-11T>C)]. Patient 1 presented with a neonatal progeroid syndrome and developed parkinsonism, dystonia, ataxia, and spasticity. Patient 2 presented with infant-onset rapidly progressive chorea, and dystonia. Three patients (patients 3, 5, 6) presented predominantly with ataxia in combination with spasticity and dystonia. Patient 4 developed segmental dystonia during adolescence and ataxia in early adulthood. Four patients had vertical gaze impairment. The most common brain MRI abnormality was T2-weighted/FLAIR hyperintensity of the superior cerebellar peduncles and midbrain. Conclusion POLR3A-related disorders exhibit significant phenotypic pleomorphism. Vertical gaze dysfunction and T2-weighted/FLAIR hyperintensity of the superior cerebellar peduncles and midbrain may be useful signs suggestive of this condition.
Collapse
Affiliation(s)
- Alonso Zea Vera
- Department of NeurologyChildren's National HospitalWashingtonDCUSA
- Department of NeurologyGeorge Washington University School of Medicine & Health SciencesWashingtonDCUSA
| | - Adrienne Bruce
- Department of PediatricsPrisma HealthGreenvilleSouth CarolinaUSA
- University of South Carolina School of Medicine GreenvilleGreenvilleSouth CarolinaUSA
| | - Travis R. Larsh
- Division of NeurologyCincinnati Children's Hospital Medical CenterCincinnatiOhioUSA
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOhioUSA
| | - Zachary Jordan
- Department of NeurologyUniversity of Cincinnati Gardner Neuroscience InstituteCincinnatiOhioUSA
| | - Norbert Brüggemann
- Institute of NeurogeneticsUniversity of LübeckLübeckGermany
- Department of NeurologyUniversity of LübeckLübeckGermany
| | | | - Alberto J. Espay
- Department of NeurologyUniversity of Cincinnati Gardner Neuroscience InstituteCincinnatiOhioUSA
| | - Donald L. Gilbert
- Division of NeurologyCincinnati Children's Hospital Medical CenterCincinnatiOhioUSA
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOhioUSA
| | - Steve W. Wu
- Division of NeurologyCincinnati Children's Hospital Medical CenterCincinnatiOhioUSA
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOhioUSA
| |
Collapse
|
24
|
Pinard M, Dastpeyman S, Poitras C, Bernard G, Gauthier MS, Coulombe B. Riluzole partially restores RNA polymerase III complex assembly in cells expressing the leukodystrophy-causative variant POLR3B R103H. Mol Brain 2022; 15:98. [PMID: 36451185 PMCID: PMC9710144 DOI: 10.1186/s13041-022-00974-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 10/16/2022] [Indexed: 12/12/2022] Open
Abstract
The mechanism of assembly of RNA polymerase III (Pol III), the 17-subunit enzyme that synthesizes tRNAs, 5 S rRNA, and other small-nuclear (sn) RNAs in eukaryotes, is not clearly understood. The recent discovery of the HSP90 co-chaperone PAQosome (Particle for Arrangement of Quaternary structure) revealed a function for this machinery in the biogenesis of nuclear RNA polymerases. However, the connection between Pol III subunits and the PAQosome during the assembly process remains unexplored. Here, we report the development of a mass spectrometry-based assay that allows the characterization of Pol III assembly. This assay was used to dissect the stages of Pol III assembly, to start defining the function of the PAQosome in this process, to dissect the assembly defects driven by the leukodystrophy-causative R103H substitution in POLR3B, and to discover that riluzole, an FDA-approved drug for alleviation of ALS symptoms, partly corrects these assembly defects. Together, these results shed new light on the mechanism and regulation of human nuclear Pol III biogenesis.
Collapse
Affiliation(s)
- Maxime Pinard
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada
| | - Samaneh Dastpeyman
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada
| | - Christian Poitras
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada
| | - Geneviève Bernard
- grid.63984.300000 0000 9064 4811Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montreal, Canada ,grid.14709.3b0000 0004 1936 8649Department of Neurology and Neurosurgery, McGill University, Montreal, Canada ,grid.14709.3b0000 0004 1936 8649Department of Human Genetics, McGill University, Montreal, Canada ,grid.14709.3b0000 0004 1936 8649Department of Pediatrics, McGill University, Montreal, Canada ,grid.63984.300000 0000 9064 4811Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Canada
| | - Marie-Soleil Gauthier
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada
| | - Benoit Coulombe
- grid.511547.30000 0001 2106 1695Translational Proteomics Laboratory, Institut de Recherches Cliniques de Montréal, Montréal, Québec Canada ,grid.14848.310000 0001 2292 3357Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, Québec Canada
| |
Collapse
|
25
|
Abstract
tRNAs are key adaptor molecules that decipher the genetic code during translation of mRNAs in protein synthesis. In contrast to the traditional view of tRNAs as ubiquitously expressed housekeeping molecules, awareness is now growing that tRNA-encoding genes display tissue-specific and cell type-specific patterns of expression, and that tRNA gene expression and function are both dynamically regulated by post-transcriptional RNA modifications. Moreover, dysregulation of tRNAs, mediated by alterations in either their abundance or function, can have deleterious consequences that contribute to several distinct human diseases, including neurological disorders and cancer. Accumulating evidence shows that reprogramming of mRNA translation through altered tRNA activity can drive pathological processes in a codon-dependent manner. This Review considers the emerging evidence in support of the precise control of functional tRNA levels as an important regulatory mechanism that coordinates mRNA translation and protein expression in physiological cell homeostasis, and highlights key examples of human diseases that are linked directly to tRNA dysregulation.
Collapse
Affiliation(s)
- Esteban A Orellana
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Elisabeth Siegal
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
| | - Richard I Gregory
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.
- Harvard Initiative for RNA Medicine, Harvard University, Boston, MA, USA.
| |
Collapse
|
26
|
Nikkhah A, Rezakhani S. Developmental regression and movement disorder as a phenotypic variant of POLR3A Mutation-Case report. Clin Case Rep 2022; 10:e6556. [PMID: 36397839 PMCID: PMC9664542 DOI: 10.1002/ccr3.6556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 10/04/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022] Open
Abstract
POLR3A is a main subunit encoding RNA polymerase III, which is involved in transcription of many RNA structures. Here, we report a new presentation of c.1771-6C > G intronic variant presenting as developmental regression, seizure, and dystonia in a 6-year-old boy associated with striatum involvement in the brain MRI.
Collapse
Affiliation(s)
- Ali Nikkhah
- Pediatric Neurology Research CenterMofid Children's Hospital, Shahid Beheshti University of Medical SciencesTehranIran
| | - Sepideh Rezakhani
- Pediatric Neurology Research CenterMofid Children's Hospital, Shahid Beheshti University of Medical SciencesTehranIran
| |
Collapse
|
27
|
Peng Q, Zhang Y, Xian B, Wu L, Ding J, Ding W, Zhang X, Ding B, Li D, Wu J, Hu X, Lu G. A synonymous variant contributes to a rare Wiedemann-Rautenstrauch syndrome complicated with mild anemia via affecting pre-mRNA splicing. Front Mol Neurosci 2022; 15:1026530. [DOI: 10.3389/fnmol.2022.1026530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/11/2022] [Indexed: 11/13/2022] Open
Abstract
Wiedemann-Rautenstrauch syndrome (WDRTS) is an extremely rare autosomal recessive neonatal disorder. Currently, over 50 cases with variable phenotypes of WDRTS have been reported. In our cohort of prenatal and postnatal growth retardation, a female proband was found to have general growth retardation, neurocutaneous syndrome, and anemia. Karyotype test and array-CGH detected no obvious chromosomal aberrations. Trio-based whole-exome sequencing (Trio-WES) identified bi-allelic compound mutations in the coding sequence (CDS) of POLR3A gene (c.3342C > T, p.Ser1114 = and c.3718G > A, p.Gly1240Ser). For the mild anemia phenotype, the underlying causal genetic factors could be attributed to the compound heterozygous mutations in FANCA gene (c.2832dup, p.Ala945CysfsTer6 and c.1902 T > G, p.Asp634Glu). Mini-gene reporter assays revealed that the synonymous variant of POLR3A and the missense variant of FANCA could affect pre-mRNA splicing of each gene. For POLR3A, the synonymous mutation (c.3342C > T, p.Ser1114=) generated three types of aberrant isoforms. Therefore, the female patient was finally diagnosed as WDRTS caused by POLR3A. For FANCA, the missense variant (c.1902 T > G, p.Asp634Glu) disrupted the normal splicing between exon 21 and 22, and produced two types of abnormal isoforms, one carrying the 1902G and the other spliced between exon 21 and 23 to exclude exon 22. Network analysis showed that POLR3A and FANCA could be STRINGed, indicating both proteins might collaborate for some unknown functions. Current investigation would broaden the knowledge for clinicians and genetic counselors and remind them to interpret those synonymous or predicted “benign” variants more carefully.
Collapse
|
28
|
Musumeci A, Calì F, Scuderi C, Vinci M, Vitello GA, Musumeci SA, Chiavetta V, Federico C, Amore G, Saccone S, Di Rosa G, Nicotera AG. Identification of a Novel Missense Mutation of POLR3A Gene in a Cohort of Sicilian Patients with Leukodystrophy. Biomedicines 2022; 10:biomedicines10092276. [PMID: 36140376 PMCID: PMC9496502 DOI: 10.3390/biomedicines10092276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 12/02/2022] Open
Abstract
Recessive mutations in the POLR3A gene cause POLR3-HLD (the second-most-common form of childhood-onset hypomyelinating leukodystrophy), a neurodegenerative disorder featuring deficient cerebral myelin formation. To date, more than 140 POLR3A (NM_007055.3) missense mutations are related to the pathogenesis of POLR3-related leukodystrophy and spastic ataxia. Herein, in a cohort of five families from Sicily (Italy), we detected two cases of patients affected by POLR3-related leukodystrophy, one due to a compound heterozygous mutation in the POLR3A gene, including a previously undescribed missense mutation (c.328A > G (p.Lys110Glu)). Our study used an in-house NGS gene panel comprising 41 known leukodystrophy genes. Successively, we used a predictive test supporting the missense mutation as causative of disease, thus this mutation can be considered “Likely Pathogenic” and could be as a new pathogenetic mutation of the POLR3A gene causing a severe form of POLR3-HLD.
Collapse
Affiliation(s)
- Antonino Musumeci
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy
| | - Francesco Calì
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy
| | - Carmela Scuderi
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy
| | - Mirella Vinci
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy
| | | | | | - Valeria Chiavetta
- Oasi Research Institute—IRCCS, Via Conte Ruggero 73, 94018 Troina, Italy
| | - Concetta Federico
- Department Biological, Geological and Environmental Sciences, University of Catania, Via Androne 81, 95124 Catania, Italy
| | - Greta Amore
- Department of Human Pathology of the Adult and Developmental Age, “Gaetano Barresi” University of Messina, Via Consolare Valeria 1, 98125 Messina, Italy
| | - Salvatore Saccone
- Department Biological, Geological and Environmental Sciences, University of Catania, Via Androne 81, 95124 Catania, Italy
- Correspondence:
| | - Gabriella Di Rosa
- Department of Human Pathology of the Adult and Developmental Age, “Gaetano Barresi” University of Messina, Via Consolare Valeria 1, 98125 Messina, Italy
| | - Antonio Gennaro Nicotera
- Department of Human Pathology of the Adult and Developmental Age, “Gaetano Barresi” University of Messina, Via Consolare Valeria 1, 98125 Messina, Italy
| |
Collapse
|
29
|
Bai H, Li D, Zheng Y, Jiang X. Case report: Biallelic variants in POLR3B gene lead to 4H leukodystrophy from the study of brother and sister. Medicine (Baltimore) 2022; 101:e30350. [PMID: 36042647 PMCID: PMC9410618 DOI: 10.1097/md.0000000000030350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
INTRODUCTION 4H leukodystrophy, one of POLR3-related leukodystrophy, is a rare hereditary brain white matter disease caused by the pathogenic biallelic variations in POLR3A, POLR3B, or POLR1C. Hypomyelination, hypodontia, and hypogonadotropic hypogonadism is mainly presented in patients with 4H leukodystrophy. PATIENT CONCERNS Here, we reported the brother and the sister with new compound heterozygous (c.1615G>T and c.165-167del) with various degrees of phenotypes including dysbasia, myopia, dental abnormal, and hypogonadotropic hypogonadism. DIAGNOSIS The brother and sister were diagnosed with 4H leukodystrophy. INTERVENTIONS Gonadotrophins treatment of the brother could significantly improve the development of secondary sexual characteristics and genitalia. OUTCOMES This study showed that the same genotype of POLR3B may have variable clinical phenotypes in the brother and sister. CONCLUSION The exploration of molecular functions and genetic counseling are crucial for further diagnosis and treatment of POLR3-related leukodystrophy.
Collapse
Affiliation(s)
- Hengzhou Bai
- Andrology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Key Laboratory of Birth Defects and Related Disease of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Dingming Li
- Andrology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Key Laboratory of Birth Defects and Related Disease of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yi Zheng
- Andrology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Key Laboratory of Birth Defects and Related Disease of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - XiaoHui Jiang
- Andrology, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Key Laboratory of Birth Defects and Related Disease of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- *Correspondence: XiaoHui Jiang, Andrology, West China Second University Hospital, Sichuan University, No. 1416, Section 1, Cheng Long Avenue, Chengdu, Sichuan 610011, China (e-mail: )
| |
Collapse
|
30
|
Martin S, Allan KC, Pinkard O, Sweet T, Tesar PJ, Coller J. Oligodendrocyte differentiation alters tRNA modifications and codon optimality-mediated mRNA decay. Nat Commun 2022; 13:5003. [PMID: 36008413 PMCID: PMC9411196 DOI: 10.1038/s41467-022-32766-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 08/15/2022] [Indexed: 11/08/2022] Open
Abstract
Oligodendrocytes are specialized cells that confer neuronal myelination in the central nervous system. Leukodystrophies associated with oligodendrocyte deficits and hypomyelination are known to result when a number of tRNA metabolism genes are mutated. Thus, for unknown reasons, oligodendrocytes may be hypersensitive to perturbations in tRNA biology. In this study, we survey the tRNA transcriptome in the murine oligodendrocyte cell lineage and find that specific tRNAs are hypomodified in oligodendrocytes within or near the anticodon compared to oligodendrocyte progenitor cells (OPCs). This hypomodified state may be the result of differential expression of key modification enzymes during oligodendrocyte differentiation. Moreover, we observe a concomitant relationship between tRNA hypomodification and tRNA decoding potential; observing oligodendrocyte specific alterations in codon optimality-mediated mRNA decay and ribosome transit. Our results reveal that oligodendrocytes naturally maintain a delicate, hypersensitized tRNA/mRNA axis. We suggest this axis is a potential mediator of pathology in leukodystrophies and white matter disease when further insult to tRNA metabolism is introduced.
Collapse
Affiliation(s)
- Sophie Martin
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Kevin C Allan
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Otis Pinkard
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Thomas Sweet
- Center for Proteomics and Bioinformatics, Department of Nutrition, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Paul J Tesar
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Jeff Coller
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Biology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| |
Collapse
|
31
|
Nowacki JC, Fields AM, Fu MM. Emerging cellular themes in leukodystrophies. Front Cell Dev Biol 2022; 10:902261. [PMID: 36003149 PMCID: PMC9393611 DOI: 10.3389/fcell.2022.902261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 06/30/2022] [Indexed: 11/18/2022] Open
Abstract
Leukodystrophies are a broad spectrum of neurological disorders that are characterized primarily by deficiencies in myelin formation. Clinical manifestations of leukodystrophies usually appear during childhood and common symptoms include lack of motor coordination, difficulty with or loss of ambulation, issues with vision and/or hearing, cognitive decline, regression in speech skills, and even seizures. Many cases of leukodystrophy can be attributed to genetic mutations, but they have diverse inheritance patterns (e.g., autosomal recessive, autosomal dominant, or X-linked) and some arise from de novo mutations. In this review, we provide an updated overview of 35 types of leukodystrophies and focus on cellular mechanisms that may underlie these disorders. We find common themes in specialized functions in oligodendrocytes, which are specialized producers of membranes and myelin lipids. These mechanisms include myelin protein defects, lipid processing and peroxisome dysfunction, transcriptional and translational dysregulation, disruptions in cytoskeletal organization, and cell junction defects. In addition, non-cell-autonomous factors in astrocytes and microglia, such as autoimmune reactivity, and intercellular communication, may also play a role in leukodystrophy onset. We hope that highlighting these themes in cellular dysfunction in leukodystrophies may yield conceptual insights on future therapeutic approaches.
Collapse
|
32
|
Yoon Han J, Gon Cho Y, Park J, Jang W. A novel variant of the POLR3A gene in a patient with hypomyelinating POLR3-related leukodystrophy. Clin Chim Acta 2022; 533:15-21. [PMID: 35691411 DOI: 10.1016/j.cca.2022.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/04/2022] [Accepted: 06/05/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND Hypomyelinating POLR3-related leukodystrophy is a group of rare neurological diseases characterized by degeneration of the white matter of the brain with different combinations of major clinical findings. Here we report the first Korean POLR3-related leukodystrophy caused by bi-allelic POLR3A c.1771-6C > G and novel c.1650_1661del variants. METHODS An 18-month-old girl was admitted for evaluation of a seizure-like activity with spasticity that affected her entire body. She showed dental abnormalities, but not suspicious facial dysmorphism. She was in a bed-ridden state with severe cognitive impairments and episodes of dystonic posturing for 1-2 min. Trio exome sequencing (ES) was performed to determine the potential genetic cause of severe developmental delay with leukodystrophy in our proband. RESULTS Trio ES revealed that bi-allelic POLR3A deleterious variants, c.1650_1661del of the exon 13, and c.1771-6C > G of the intron 13 were best candidate as causes of hypomyelinating POLR3-related leukodystrophy. Sanger sequencing confirmed the genetic origin of these POLR3A deleterious variants as autosomal recessive hereditary transmission. CONCLUSION Our report provides additional evidence for a phenotypic continuum of hypomyelinating POLR3-related leukodystrophy caused by bi-allelic POLR3A variants. Further genetic studies are required to understand underlying pleiotropic effects of different POLR3A variants.
Collapse
Affiliation(s)
- Ji Yoon Han
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Yong Gon Cho
- Department of Laboratory Medicine, Jeonbuk National University Medical School and Hospital, Jeonju, Korea; Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Korea
| | - Joonhong Park
- Department of Laboratory Medicine, Jeonbuk National University Medical School and Hospital, Jeonju, Korea; Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Korea.
| | - Woori Jang
- Department of Laboratory Medicine, Inha University School of Medicine, Incheon, Korea.
| |
Collapse
|
33
|
Ando M, Higuchi Y, Yuan JH, Yoshimura A, Kitao R, Morimoto T, Taniguchi T, Takeuchi M, Takei J, Hiramatsu Y, Sakiyama Y, Hashiguchi A, Okamoto Y, Mitsui J, Ishiura H, Tsuji S, Takashima H. Novel de novo POLR3B mutations responsible for demyelinating Charcot-Marie-Tooth disease in Japan. Ann Clin Transl Neurol 2022; 9:747-755. [PMID: 35482004 PMCID: PMC9082381 DOI: 10.1002/acn3.51555] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/10/2022] [Accepted: 03/24/2022] [Indexed: 12/24/2022] Open
Abstract
Background Biallelic POLR3B mutations cause a rare hypomyelinating leukodystrophy. De novo POLR3B heterozygous mutations were recently associated with afferent ataxia, spasticity, variable intellectual disability, and epilepsy, and predominantly demyelinating sensorimotor peripheral neuropathy. Methods We performed whole‐exome sequencing (WES) of DNA samples from 804 Charcot–Marie–Tooth (CMT) cases that could not be genetically diagnosed by DNA‐targeted resequencing microarray using next‐generation sequencers. Using WES data, we analyzed the POLR3B mutations and confirmed their clinical features. Results We identified de novo POLR3B heterozygous missense mutations in two patients. These patients presented with early‐onset demyelinating sensorimotor neuropathy without ataxia, spasticity, or cognitive impairment. Patient 1 showed mild cerebellar atrophy and spinal cord atrophy on magnetic resonance imaging and eventually died of respiratory failure in her 50s. We classified these mutations as pathogenic based on segregation studies, comparison with control database, and in silico analysis. Conclusion Our study is the third report on patients with demyelinating CMT harboring heterozygous POLR3B mutations and verifies the pathogenicity of POLR3B mutations in CMT. Although extremely rare in our large Japanese case series, POLR3B mutations should be added to the CMT‐related gene panel for comprehensive genetic screening, particularly for patients with early‐onset demyelinating CMT.
Collapse
Affiliation(s)
- Masahiro Ando
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yujiro Higuchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Jun-Hui Yuan
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Akiko Yoshimura
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Ruriko Kitao
- Department of Neurology, National Hospital Organization Hakone Hospital, Kanagawa, Japan
| | - Takehiko Morimoto
- Department of Pediatrics, Asahigawaso Minamiehime Rehabilitation Hospital, Ehime, Japan
| | - Takaki Taniguchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.,Department of Neurology, Imakiire General Hospital, Kagoshima, Japan
| | - Mika Takeuchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Jun Takei
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yu Hiramatsu
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yusuke Sakiyama
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Akihiro Hashiguchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Yuji Okamoto
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.,Department of Physical Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, Kagoshima, Japan
| | - Jun Mitsui
- Department of Molecular Neurology, Graduate School of Medicine, The University of Tokyo, Chiba, Japan
| | - Hiroyuki Ishiura
- Department of Neurology, Faculty of Medicine, The University of Tokyo, Chiba, Japan
| | - Shoji Tsuji
- Department of Molecular Neurology, Graduate School of Medicine, The University of Tokyo, Chiba, Japan.,Institute of Medical Genomics, International University of Health and Welfare, Chiba, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| |
Collapse
|
34
|
Costei C, Barbarosie M, Bernard G, Brais B, La Piana R. Adult Hereditary White Matter Diseases With Psychiatric Presentation: Clinical Pointers and MRI Algorithm to Guide the Diagnostic Process. J Neuropsychiatry Clin Neurosci 2022; 33:180-193. [PMID: 33951919 DOI: 10.1176/appi.neuropsych.20110294] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The investigators aimed to provide clinical and MRI guidelines for determining when genetic workup should be considered in order to exclude hereditary leukoencephalopathies in affected patients with a psychiatric presentation. METHODS A systematic literature review was conducted, and clinical cases are provided. Given the central role of MRI pattern recognition in the diagnosis of white matter disorders, the investigators adapted an MRI algorithm that guides the interpretation of MRI findings and thus directs further investigations, such as genetic testing. RESULTS Twelve genetic leukoencephalopathies that can present with psychiatric symptoms were identified. As examples of presentations that can occur in clinical practice, five clinical vignettes from patients assessed at a referral center for adult genetic leukoencephalopathies are provided. CONCLUSIONS Features such as drug-resistant symptoms, presence of long-standing somatic features, trigger events, consanguinity, and positive family history should orient the clinician toward diagnostic workup to exclude the presence of a genetic white matter disorder. The identification of MRI white matter abnormalities, especially when presenting a specific pattern of involvement, should prompt genetic testing for known forms of genetic leukoencephalopathies.
Collapse
Affiliation(s)
- Catalina Costei
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal (Costei, Brais, La Piana); Department of Psychiatry, McGill University (Barbarosie); Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University (Bernard); Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal (Bernard); Child Health and Human Development Program, Research Institute of the McGill University Health Center (Bernard); and Department of Diagnostic Radiology, McGill University (La Piana)
| | - Michaela Barbarosie
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal (Costei, Brais, La Piana); Department of Psychiatry, McGill University (Barbarosie); Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University (Bernard); Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal (Bernard); Child Health and Human Development Program, Research Institute of the McGill University Health Center (Bernard); and Department of Diagnostic Radiology, McGill University (La Piana)
| | - Geneviève Bernard
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal (Costei, Brais, La Piana); Department of Psychiatry, McGill University (Barbarosie); Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University (Bernard); Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal (Bernard); Child Health and Human Development Program, Research Institute of the McGill University Health Center (Bernard); and Department of Diagnostic Radiology, McGill University (La Piana)
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal (Costei, Brais, La Piana); Department of Psychiatry, McGill University (Barbarosie); Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University (Bernard); Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal (Bernard); Child Health and Human Development Program, Research Institute of the McGill University Health Center (Bernard); and Department of Diagnostic Radiology, McGill University (La Piana)
| | - Roberta La Piana
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal (Costei, Brais, La Piana); Department of Psychiatry, McGill University (Barbarosie); Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University (Bernard); Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal (Bernard); Child Health and Human Development Program, Research Institute of the McGill University Health Center (Bernard); and Department of Diagnostic Radiology, McGill University (La Piana)
| |
Collapse
|
35
|
Sawaguchi S, Suzuki R, Oizumi H, Ohbuchi K, Mizoguchi K, Yamamoto M, Miyamoto Y, Yamauchi J. Hypomyelinating Leukodystrophy 8 (HLD8)-Associated Mutation of POLR3B Leads to Defective Oligodendroglial Morphological Differentiation Whose Effect Is Reversed by Ibuprofen. Neurol Int 2022; 14:212-244. [PMID: 35225888 PMCID: PMC8884015 DOI: 10.3390/neurolint14010018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 02/03/2022] [Accepted: 02/14/2022] [Indexed: 11/16/2022] Open
Abstract
POLR3B and POLR3A are the major subunits of RNA polymerase III, which synthesizes non-coding RNAs such as tRNAs and rRNAs. Nucleotide mutations of the RNA polymerase 3 subunit b (polr3b) gene are responsible for hypomyelinating leukodystrophy 8 (HLD8), which is an autosomal recessive oligodendroglial cell disease. Despite the important association between POLR3B mutation and HLD8, it remains unclear how mutated POLR3B proteins cause oligodendroglial cell abnormalities. Herein, we show that a severe HLD8-associated nonsense mutation (Arg550-to-Ter (R550X)) primarily localizes POLR3B proteins as protein aggregates into lysosomes in the FBD-102b cell line as an oligodendroglial precursor cell model. Conversely, wild type POLR3B proteins were not localized in lysosomes. Additionally, the expression of proteins with the R550X mutation in cells decreased lysosome-related signaling through the mechanistic target of rapamycin (mTOR). Cells harboring the mutant constructs did not exhibit oligodendroglial cell differentiated phenotypes, which have widespread membranes that extend from their cell body. However, cells harboring the wild type constructs exhibited differentiated phenotypes. Ibuprofen, which is a non-steroidal anti-inflammatory drug (NSAID), improved the defects in their differentiation phenotypes and signaling through mTOR. These results indicate that the HLD8-associated POLR3B proteins with the R550X mutation are localized in lysosomes, decrease mTOR signaling, and inhibit oligodendroglial cell morphological differentiation, and ibuprofen improves these cellular pathological effects. These findings may reveal some of the molecular and cellular pathological mechanisms underlying HLD8 and their amelioration.
Collapse
Affiliation(s)
- Sui Sawaguchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji 192-0392, Japan; (S.S.); (R.S.); (Y.M.)
| | - Rimi Suzuki
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji 192-0392, Japan; (S.S.); (R.S.); (Y.M.)
| | - Hiroaki Oizumi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (K.M.); (M.Y.)
| | - Katsuya Ohbuchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (K.M.); (M.Y.)
| | - Kazushige Mizoguchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (K.M.); (M.Y.)
| | - Masahiro Yamamoto
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (K.M.); (M.Y.)
| | - Yuki Miyamoto
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji 192-0392, Japan; (S.S.); (R.S.); (Y.M.)
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya 157-8535, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji 192-0392, Japan; (S.S.); (R.S.); (Y.M.)
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya 157-8535, Japan
- Correspondence: ; Tel.: +81-42-676-7164; Fax: +81-42-676-8841
| |
Collapse
|
36
|
Abstract
RNA polymerase III (Pol III) is a large multisubunit complex conserved in all eukaryotes that plays an essential role in producing a variety of short non-coding RNAs, such as tRNA, 5S rRNA and U6 snRNA transcripts. Pol III comprises of 17 subunits in both yeast and human with a 10-subunit core and seven peripheral subunits. Because of its size and complexity, Pol III has posed a formidable challenge to structural biologists. The first atomic cryogenic electron microscopy structure of yeast Pol III leading to the canonical view was reported in 2015. Within the last few years, the optimization of endogenous extract and purification procedure and the technical and methodological advances in cryogenic electron microscopy, together allow us to have a first look at the unprecedented details of human Pol III organization. Here, we look back on the structural studies of human Pol III and discuss them in the light of our current understanding of its role in eukaryotic transcription.
Collapse
Affiliation(s)
- Qianmin Wang
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
| | - Ming Lei
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China.,State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Wu
- Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai, China
| |
Collapse
|
37
|
Javidnia S, Cranwell S, Mueller SH, Selman C, Tullet JM, Kuchenbaecker K, Alic N. Mendelian randomization analyses implicate biogenesis of translation machinery in human aging. Genome Res 2022; 32:258-265. [PMID: 35078808 PMCID: PMC8805714 DOI: 10.1101/gr.275636.121] [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: 04/13/2021] [Accepted: 12/15/2021] [Indexed: 11/25/2022]
Abstract
Reduced provision of protein translation machinery promotes healthy aging in a number of animal models. In humans, however, inborn impairments in translation machinery are a known cause of several developmental disorders, collectively termed ribosomopathies. Here, we use casual inference approaches in genetic epidemiology to investigate whether adult, tissue-specific biogenesis of translation machinery drives human aging. We assess naturally occurring variation in the expression of genes encoding subunits specific to the two RNA polymerases (Pols) that transcribe ribosomal and transfer RNAs, namely Pol I and III, and the variation in expression of ribosomal protein (RP) genes, using Mendelian randomization. We find each causally associated with human longevity (β = −0.15 ± 0.047, P = 9.6 × 10−4, q = 0.015; β = −0.13 ± 0.040, P = 1.4 × 10−3, q = 0.023; β = −0.048 ± 0.016, P = 3.5 × 10−3, q = 0.056, respectively), and this does not appear to be mediated by altered susceptibility to a single disease. We find that reduced expression of Pol III, RPs, or Pol I promotes longevity from different organs, namely visceral adipose, liver, and skeletal muscle, echoing the tissue specificity of ribosomopathies. Our study shows the utility of leveraging genetic variation in expression to elucidate how essential cellular processes impact human aging. The findings extend the evolutionary conservation of protein synthesis as a critical process that drives animal aging to include humans.
Collapse
|
38
|
Naseer MI, Abdulkareem AA, Pushparaj PN, Saharti S, Muthaffar OY. Next-Generation Sequencing Reveals Novel Homozygous Missense Variant c.934T > C in POLR1C Gene Causing Leukodystrophy and Hypomyelinating Disease. Front Pediatr 2022; 10:862722. [PMID: 35685919 PMCID: PMC9171136 DOI: 10.3389/fped.2022.862722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/07/2022] [Indexed: 11/13/2022] Open
Abstract
Leukodystrophies are a diverse group of genetically established disorders categorized by unusual white matter changes on brain imaging. Hypomyelinating leukodystrophies (HLDs) are a group of neurodevelopmental disorders that affect myelin sheath development in the brain. These disorders are categorized as developmental delay, spasticity, hypotonia, and intellectual disabilities. We describe a patient with developmental delay, cerebellar ataxia, spasticity, hypotonia, and intellectual disability from a healthy family member. Whole exome sequencing (WES) was performed to identify causative variants, which were further analyzed by bioinformatic analysis. WES was performed, and Sanger sequencing-based segregation analysis confirmed the presence of the homozygous missense variants of NM_203290.3 c.934T > C p.Ser312Pro of RNA polymerase I and III subunit C (POLR1C) gene in this patient and heterozygous variant in the unaffected carrier father and mother, supporting the pathogenicity and inheritance pattern of this variant. Furthermore, the variant identified by WES was validated in healthy controls (n = 100) using Sanger sequencing analysis. Finally, our study explained the important use of WES in disease diagnosis and provided further evidence that the variant in the POLR1C gene may play an important role in the development of hypomyelinating leukodystrophy in Saudi families.
Collapse
Affiliation(s)
- Muhammad Imran Naseer
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Angham Abdulrahman Abdulkareem
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Peter Natesan Pushparaj
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Pharmacology, Center for Transdisciplinary Research, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Chennai, India
| | - Samah Saharti
- Department of Pathology and Microbiology, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Osama Y Muthaffar
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| |
Collapse
|
39
|
Abstract
Idiopathic hypogonadotropic hypogonadism (IHH) is a group of rare developmental disorders characterized by low gonadotropin levels in the face of low sex steroid hormone concentrations. IHH is practically divided into two major groups according to the olfactory function: normal sense of smell (normosmia) nIHH, and reduced sense of smell (hyposmia/anosmia) Kallmann syndrome (KS). Although mutations in more than 50 genes have been associated with IHH so far, only half of those cases were explained by gene mutations. Various combinations of deleterious variants in different genes as causes of IHH have been increasingly recognized (Oligogenic etiology). In addition to the complexity of inheritance patterns, the spontaneous or sex steroid-induced clinical recovery from IHH, which is seen in approximately 10–20% of cases, blurs further the phenotype/genotype relationship in IHH, and poses challenging steps in new IHH gene discovery. Beyond helping for clinical diagnostics, identification of the genetic mutations in the pathophysiology of IHH is hoped to shed light on the central governance of the hypothalamo-pituitary-gonadal axis through life stages. This review aims to summarize the genetic etiology of IHH and discuss the clinical and physiological ramifications of the gene mutations.
Collapse
|
40
|
Sawaguchi S, Tago K, Oizumi H, Ohbuchi K, Yamamoto M, Mizoguchi K, Miyamoto Y, Yamauchi J. Hypomyelinating Leukodystrophy 7 (HLD7)-Associated Mutation of POLR3A Is Related to Defective Oligodendroglial Cell Differentiation, Which Is Ameliorated by Ibuprofen. Neurol Int 2021; 14:11-33. [PMID: 35076634 PMCID: PMC8788570 DOI: 10.3390/neurolint14010002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/14/2021] [Accepted: 12/21/2021] [Indexed: 01/13/2023] Open
Abstract
Hypomyelinating leukodystrophy 7 (HLD7) is an autosomal recessive oligodendroglial cell-related myelin disease, which is associated with some nucleotide mutations of the RNA polymerase 3 subunit a (polr3a) gene. POLR3A is composed of the catalytic core of RNA polymerase III synthesizing non-coding RNAs, such as rRNA and tRNA. Here, we show that an HLD7-associated nonsense mutation of Arg140-to-Ter (R140X) primarily localizes POLR3A proteins as protein aggregates into lysosomes in mouse oligodendroglial FBD-102b cells, whereas the wild type proteins are not localized in lysosomes. Expression of the R140X mutant proteins, but not the wild type proteins, in cells decreased signaling through the mechanistic target of rapamycin (mTOR), controlling signal transduction around lysosomes. While cells harboring the wild type constructs exhibited phenotypes with widespread membranes with myelin marker protein expression following the induction of differentiation, cells harboring the R140X mutant constructs did not exhibit them. Ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), which is also known as an mTOR signaling activator, ameliorated defects in differentiation with myelin marker protein expression and the related signaling in cells harboring the R140X mutant constructs. Collectively, HLD7-associated POLR3A mutant proteins are localized in lysosomes where they decrease mTOR signaling, inhibiting cell morphological differentiation. Importantly, ibuprofen reverses undifferentiated phenotypes. These findings may reveal some of the pathological mechanisms underlying HLD7 and their amelioration at the molecular and cellular levels.
Collapse
Affiliation(s)
- Sui Sawaguchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (S.S.); (Y.M.)
| | - Kenji Tago
- Department of Biochemistry, Jichi Medical University, Shimotsuke 321-0498, Japan;
| | - Hiroaki Oizumi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (M.Y.); (K.M.)
| | - Katsuya Ohbuchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (M.Y.); (K.M.)
| | - Masahiro Yamamoto
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (M.Y.); (K.M.)
| | - Kazushige Mizoguchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki 200-1192, Japan; (H.O.); (K.O.); (M.Y.); (K.M.)
| | - Yuki Miyamoto
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (S.S.); (Y.M.)
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (S.S.); (Y.M.)
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
- Correspondence: ; Tel.: +81-42-676-7164; Fax: +81-42-676-8841
| |
Collapse
|
41
|
Whittaker DE, Oleari R, Gregory LC, Le Quesne-Stabej P, Williams HJ, Torpiano JG, Formosa N, Cachia MJ, Field D, Lettieri A, Ocaka LA, Paganoni AJ, Rajabali SH, Riegman KL, De Martini LB, Chaya T, Robinson IC, Furukawa T, Cariboni A, Basson MA, Dattani MT. A recessive PRDM13 mutation results in congenital hypogonadotropic hypogonadism and cerebellar hypoplasia. J Clin Invest 2021; 131:e141587. [PMID: 34730112 PMCID: PMC8670848 DOI: 10.1172/jci141587] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 10/27/2021] [Indexed: 11/17/2022] Open
Abstract
The positive regulatory (PR) domain containing 13 (PRDM13) putative chromatin modifier and transcriptional regulator functions downstream of the transcription factor PTF1A, which controls GABAergic fate in the spinal cord and neurogenesis in the hypothalamus. Here, we report a recessive syndrome associated with PRDM13 mutation. Patients exhibited intellectual disability, ataxia with cerebellar hypoplasia, scoliosis, and delayed puberty with congenital hypogonadotropic hypogonadism (CHH). Expression studies revealed Prdm13/PRDM13 transcripts in the developing hypothalamus and cerebellum in mouse and human. An analysis of hypothalamus and cerebellum development in mice homozygous for a Prdm13 mutant allele revealed a significant reduction in the number of Kisspeptin (Kiss1) neurons in the hypothalamus and PAX2+ progenitors emerging from the cerebellar ventricular zone. The latter was accompanied by ectopic expression of the glutamatergic lineage marker TLX3. Prdm13-deficient mice displayed cerebellar hypoplasia and normal gonadal structure, but delayed pubertal onset. Together, these findings identify PRDM13 as a critical regulator of GABAergic cell fate in the cerebellum and of hypothalamic kisspeptin neuron development, providing a mechanistic explanation for the cooccurrence of CHH and cerebellar hypoplasia in this syndrome. To our knowledge, this is the first evidence linking disrupted PRDM13-mediated regulation of Kiss1 neurons to CHH in humans.
Collapse
Affiliation(s)
- Danielle E. Whittaker
- Centre for Craniofacial and Regenerative Biology, King’s College London, London, United Kingdom
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom
| | - Roberto Oleari
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Louise C. Gregory
- Section of Molecular Basis of Rare Disease, Genetics and Genomic Medicine Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Polona Le Quesne-Stabej
- Section of Molecular Basis of Rare Disease, Genetics and Genomic Medicine Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Hywel J. Williams
- Section of Molecular Basis of Rare Disease, Genetics and Genomic Medicine Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - GOSgene
- Section of Molecular Basis of Rare Disease, Genetics and Genomic Medicine Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
- GOSgene is detailed in Supplemental Acknowledgments
| | - John G. Torpiano
- Department of Paediatrics and
- Adult Endocrinology Service, Mater Dei Hospital, Msida, Malta
| | | | - Mario J. Cachia
- Adult Endocrinology Service, Mater Dei Hospital, Msida, Malta
| | - Daniel Field
- Centre for Craniofacial and Regenerative Biology, King’s College London, London, United Kingdom
| | - Antonella Lettieri
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Louise A. Ocaka
- Section of Molecular Basis of Rare Disease, Genetics and Genomic Medicine Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Alyssa J.J. Paganoni
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Sakina H. Rajabali
- Centre for Craniofacial and Regenerative Biology, King’s College London, London, United Kingdom
| | - Kimberley L.H. Riegman
- Centre for Craniofacial and Regenerative Biology, King’s College London, London, United Kingdom
| | - Lisa B. De Martini
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Taro Chaya
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | | | - Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Anna Cariboni
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - M. Albert Basson
- Centre for Craniofacial and Regenerative Biology, King’s College London, London, United Kingdom
- MRC Centre for Neurodevelopmental Disorders, King’s College London, London, United Kingdom
| | - Mehul T. Dattani
- Section of Molecular Basis of Rare Disease, Genetics and Genomic Medicine Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| |
Collapse
|
42
|
Mishra S, Hasan SH, Sakhawala RM, Chaudhry S, Maraia RJ. Mechanism of RNA polymerase III termination-associated reinitiation-recycling conferred by the essential function of the N terminal-and-linker domain of the C11 subunit. Nat Commun 2021; 12:5900. [PMID: 34625550 PMCID: PMC8501072 DOI: 10.1038/s41467-021-26080-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 09/17/2021] [Indexed: 01/06/2023] Open
Abstract
RNA polymerase III achieves high level tRNA synthesis by termination-associated reinitiation-recycling that involves the essential C11 subunit and heterodimeric C37/53. The C11-CTD (C-terminal domain) promotes Pol III active center-intrinsic RNA 3'-cleavage although deciphering function for this activity has been complicated. We show that the isolated NTD (N-terminal domain) of C11 stimulates Pol III termination by C37/53 but not reinitiation-recycling which requires the NTD-linker (NTD-L). By an approach different from what led to current belief that RNA 3'-cleavage activity is essential, we show that NTD-L can provide the essential function of Saccharomyces cerevisiae C11 whereas classic point mutations that block cleavage, interfere with active site function and are toxic to growth. Biochemical and in vivo analysis including of the C11 invariant central linker led to a model for Pol III termination-associated reinitiation-recycling. The C11 NTD and CTD stimulate termination and RNA 3'-cleavage, respectively, whereas reinitiation-recycling activity unique to Pol III requires only the NTD-linker. RNA 3'-cleavage activity increases growth rate but is nonessential.
Collapse
Affiliation(s)
- Saurabh Mishra
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- Department of Biochemistry, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Shaina H Hasan
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- Mayo Clinic Alix School of Medicine, Scottsdale, AZ, USA
| | - Rima M Sakhawala
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- Section on Regulatory RNA, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Shereen Chaudhry
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- Pfizer (Pearl River Site), 401 N Middletown Rd, Pearl River, NY, USA
| | - Richard J Maraia
- Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
| |
Collapse
|
43
|
Lessel D, Rading K, Campbell SE, Thiele H, Altmüller J, Gordon LB, Kubisch C. A novel homozygous synonymous variant further expands the phenotypic spectrum of POLR3A-related pathologies. Am J Med Genet A 2021; 188:216-223. [PMID: 34611991 DOI: 10.1002/ajmg.a.62525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/21/2021] [Accepted: 09/06/2021] [Indexed: 12/18/2022]
Abstract
Pathogenic biallelic variants in POL3RA have been associated with different disorders characterized by progressive neurological deterioration. These include the 4H leukodystrophy syndrome (hypomyelination, hypogonadotropic hypogonadism, and hypodontia) and adolescent-onset progressive spastic ataxia, as well as Wiedemann-Rautenstrauch syndrome (WRS), a recognizable neonatal progeroid syndrome. The phenotypic differences between these disorders are thought to occur mainly due to different functional effects of underlying POLR3A variants. Here we present the detailed clinical course of a 37-year-old woman in whom we identified a homozygous synonymous POLR3A variant c.3336G>A resulting in leaky splicing r.[3336ins192, =, 3243_3336del94]. She presented at birth with intrauterine growth retardation, lipodystrophy, muscular hypotonia, and several WRS-like facial features, albeit without sparse hair and prominent scalp veins. She had no signs of developmental delay or intellectual disability. Over the years, above characteristic facial features, she showed severe postnatal growth retardation, global lipodystrophy, joint contractures, thoracic hypoplasia, scoliosis, anodontia, spastic quadriplegia, bilateral hearing loss, aphonia, hypogonadotropic hypogonadism, and cerebellar peduncles hyperintensities in brain imaging. These manifestations partially overlap the clinical features of the previously reported POLR3A-associated disorders, mostly mimicking the WRS. Thus, our study expands the POLR3A-mediated phenotypic spectrum and suggests existence of a phenotypic continuum underlying biallelic POLR3A variants.
Collapse
Affiliation(s)
- Davor Lessel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Katrin Rading
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Susan E Campbell
- Center for Gerontology and Healthcare Research, Brown University, Providence, Rhode Island, USA
| | - Holger Thiele
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Janine Altmüller
- Cologne Center for Genomics, University of Cologne, Cologne, Germany.,Berlin Institute of Health, Charité-Universitätsmedizin Berlin, Core Facility Genomics, Berlin, Germany.,The Genomics unit, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Leslie B Gordon
- Department of Pediatrics, Division of Genetics, Hasbro Children's Hospital, Providence, Rhode Island, USA.,Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA.,Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Christian Kubisch
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| |
Collapse
|
44
|
Defective myelination in an RNA polymerase III mutant leukodystrophic mouse. Proc Natl Acad Sci U S A 2021; 118:2024378118. [PMID: 34583988 DOI: 10.1073/pnas.2024378118] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2021] [Indexed: 01/06/2023] Open
Abstract
RNA polymerase (Pol) III synthesizes abundant short noncoding RNAs that have essential functions in protein synthesis, secretion, and other processes. Despite the ubiquitous functions of these RNAs, mutations in Pol III subunits cause Pol III-related leukodystrophy, an early-onset neurodegenerative disease. The basis of this neural sensitivity and the mechanisms of disease pathogenesis are unknown. Here we show that mice expressing pathogenic mutations in the largest Pol III subunit, Polr3a, specifically in Olig2-expressing cells, have impaired growth and developmental delay, deficits in cognitive, sensory, and fine sensorimotor function, and hypomyelination in multiple regions of the cerebrum and spinal cord. These phenotypes reflect a subset of clinical features seen in patients. In contrast, the gross motor defects and cerebellar hypomyelination that are common features of severely affected patients are absent in the mice, suggesting a relatively mild form of the disease in this conditional model. Our results show that disease pathogenesis in the mice involves defects that reduce both the number of mature myelinating oligodendrocytes and the ability of these cells to produce a myelin sheath of normal thickness. The findings suggest unique sensitivities of oligodendrogenesis and myelination to perturbations of Pol III transcription.
Collapse
|
45
|
Barczykowski AL, Langan TJ, Vanderver A, Jalal K, Carter RL. Death rates in the U.S. due to Leukodystrophies with pediatric forms. Am J Med Genet A 2021; 185:2361-2373. [PMID: 33960638 DOI: 10.1002/ajmg.a.62248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 03/26/2021] [Accepted: 04/16/2021] [Indexed: 11/08/2022]
Abstract
To use national mortality and state death certificate records to estimate disease specific mortality rates among pediatric and adult populations for 23 leukodystrophies (LDs) with pediatric forms. Additionally, to calculate yearly prevalence and caseload of the most severe LD cases that will eventually result in pediatric death (i.e., pediatric fatality cases). Death certificate records describing cause of death were collected from states based on 10 ICD-10 codes associated with the 23 LDs. Deaths in the U.S. with these codes were distributed into categories based on proportions identified in state death certificate data. Mortality rates, prevalence, and caseload were calculated from resulting expected numbers, population sizes, and average lifetimes. An estimated 1.513 per 1,000,000 0-17 year old's died of these LDs at average age 5.2 years and 0.194 for those ≥18 at an average age of 42.3 years. Prevalence of pediatric fatality cases of these LDs declined from 1999 through 2007 and then remained constant at 6.2 per million children per year through 2012. Epidemiological information, currently lacking for rare diseases, is useful to newborn screening programs, research funding agencies, and care centers for LD patients. Methods used here are generally useful for studying rare diseases.
Collapse
Affiliation(s)
- Amy L Barczykowski
- Population Health Observatory, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York, USA
- Department of Biostatistics, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York, USA
| | - Thomas J Langan
- Hunter James Kelly Research Institute, School of Medicine and Biomedical Sciences School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
- Department of Neurology, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Adeline Vanderver
- The Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- The Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kabir Jalal
- Population Health Observatory, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York, USA
- Department of Biostatistics, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York, USA
| | - Randy L Carter
- Population Health Observatory, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York, USA
- Department of Biostatistics, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York, USA
| |
Collapse
|
46
|
Lata E, Choquet K, Sagliocco F, Brais B, Bernard G, Teichmann M. RNA Polymerase III Subunit Mutations in Genetic Diseases. Front Mol Biosci 2021; 8:696438. [PMID: 34395528 PMCID: PMC8362101 DOI: 10.3389/fmolb.2021.696438] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 07/21/2021] [Indexed: 12/24/2022] Open
Abstract
RNA polymerase (Pol) III transcribes small untranslated RNAs such as 5S ribosomal RNA, transfer RNAs, and U6 small nuclear RNA. Because of the functions of these RNAs, Pol III transcription is best known for its essential contribution to RNA maturation and translation. Surprisingly, it was discovered in the last decade that various inherited mutations in genes encoding nine distinct subunits of Pol III cause tissue-specific diseases rather than a general failure of all vital functions. Mutations in the POLR3A, POLR3C, POLR3E and POLR3F subunits are associated with susceptibility to varicella zoster virus-induced encephalitis and pneumonitis. In addition, an ever-increasing number of distinct mutations in the POLR3A, POLR3B, POLR1C and POLR3K subunits cause a spectrum of neurodegenerative diseases, which includes most notably hypomyelinating leukodystrophy. Furthermore, other rare diseases are also associated with mutations in genes encoding subunits of Pol III (POLR3H, POLR3GL) and the BRF1 component of the TFIIIB transcription initiation factor. Although the causal relationship between these mutations and disease development is widely accepted, the exact molecular mechanisms underlying disease pathogenesis remain enigmatic. Here, we review the current knowledge on the functional impact of specific mutations, possible Pol III-related disease-causing mechanisms, and animal models that may help to better understand the links between Pol III mutations and disease.
Collapse
Affiliation(s)
- Elisabeth Lata
- Bordeaux University, Inserm U 1212, CNRS UMR 5320, ARNA laboratory, Bordeaux, France
| | - Karine Choquet
- Department of Genetics, Harvard Medical School, Boston, MA, United States
| | - Francis Sagliocco
- Bordeaux University, Inserm U 1212, CNRS UMR 5320, ARNA laboratory, Bordeaux, France
| | - Bernard Brais
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Geneviève Bernard
- Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Martin Teichmann
- Bordeaux University, Inserm U 1212, CNRS UMR 5320, ARNA laboratory, Bordeaux, France
| |
Collapse
|
47
|
Derksen A, Shih HY, Forget D, Darbelli L, Tran LT, Poitras C, Guerrero K, Tharun S, Alkuraya FS, Kurdi WI, Nguyen CTE, Laberge AM, Si Y, Gauthier MS, Bonkowsky JL, Coulombe B, Bernard G. Variants in LSM7 impair LSM complexes assembly, neurodevelopment in zebrafish and may be associated with an ultra-rare neurological disease. HGG ADVANCES 2021; 2:100034. [PMID: 35047835 PMCID: PMC8756503 DOI: 10.1016/j.xhgg.2021.100034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 04/28/2021] [Indexed: 11/15/2022] Open
Abstract
Leukodystrophies, genetic neurodevelopmental and/or neurodegenerative disorders of cerebral white matter, result from impaired myelin homeostasis and metabolism. Numerous genes have been implicated in these heterogeneous disorders; however, many individuals remain without a molecular diagnosis. Using whole-exome sequencing, biallelic variants in LSM7 were uncovered in two unrelated individuals, one with a leukodystrophy and the other who died in utero. LSM7 is part of the two principle LSM protein complexes in eukaryotes, namely LSM1-7 and LSM2-8. Here, we investigate the molecular and functional outcomes of these LSM7 biallelic variants in vitro and in vivo. Affinity purification-mass spectrometry of the LSM7 variants showed defects in the assembly of both LSM complexes. Lsm7 knockdown in zebrafish led to central nervous system defects, including impaired oligodendrocyte development and motor behavior. Our findings demonstrate that variants in LSM7 cause misassembly of the LSM complexes, impair neurodevelopment of the zebrafish, and may be implicated in human disease. The identification of more affected individuals is needed before the molecular mechanisms of mRNA decay and splicing regulation are added to the categories of biological dysfunctions implicated in leukodystrophies, neurodevelopmental and/or neurodegenerative diseases.
Collapse
|
48
|
|
49
|
Coulombe B, Derksen A, La Piana R, Brais B, Gauthier MS, Bernard G. POLR3-related leukodystrophy: How do mutations affecting RNA polymerase III subunits cause hypomyelination? Fac Rev 2021; 10:12. [PMID: 33659930 PMCID: PMC7894263 DOI: 10.12703/r/10-12] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Hypomyelinating leukodystrophies are a group of genetic disorders characterized by insufficient myelin deposition during development. A subset of hypomyelinating leukodystrophies, named RNA polymerase III (Pol III or POLR3)-related leukodystrophy or 4H (Hypomyelination, Hypodontia and Hypogonadotropic Hypogonadism) leukodystrophy, was found to be caused by biallelic variants in genes encoding subunits of the enzyme Pol III, including POLR3A, POLR3B, POLR3K, and POLR1C. Pol III is one of the three nuclear RNA polymerases that synthesizes small non-coding RNAs, such as tRNAs, 5S RNA, and others, that are involved in the regulation of essential cellular processes, including transcription, translation and RNA maturation. Affinity purification coupled with mass spectrometry (AP-MS) revealed that a number of mutations causing POLR3-related leukodystrophy impair normal assembly or biogenesis of Pol III, often causing a retention of the unassembled subunits in the cytoplasm. Even though these proteomic studies have helped to understand the molecular defects associated with leukodystrophy, how these mutations cause hypomyelination has yet to be defined. In this review we propose two main hypotheses to explain how mutations affecting Pol III subunits can cause hypomyelination.
Collapse
Affiliation(s)
- Benoit Coulombe
- Department of Translational Proteomics, Institut de Recherches Cliniques de Montréal, Montréal, QC, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC, Canada
| | - Alexa Derksen
- Department of Translational Proteomics, Institut de Recherches Cliniques de Montréal, Montréal, QC, Canada
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
| | - Roberta La Piana
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
- Department of Diagnostic Radiology, McGill University, Montréal, QC, Canada
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montréal, QC, Canada
- Department of Human Genetics, McGill University, Montréal, QC, Canada
| | - Marie-Soleil Gauthier
- Department of Translational Proteomics, Institut de Recherches Cliniques de Montréal, Montréal, QC, Canada
| | - Geneviève Bernard
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, Montréal, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
- Department of Human Genetics, McGill University, Montréal, QC, Canada
- Department of Pediatrics, McGill University, Montréal, QC, Canada
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montréal, QC, Canada
| |
Collapse
|
50
|
Furukawa S, Kunii M, Doi H, Kondo N, Ogura A, Hirabuki K, Itoh T, Matsumoto N, Tanaka F, Katsuno M, Ito Y. Case Report: Severe Osteoporosis and Preventive Therapy in RNA Polymerase III-Related Leukodystrophy. Front Neurol 2021; 12:622355. [PMID: 33716926 PMCID: PMC7952608 DOI: 10.3389/fneur.2021.622355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/25/2021] [Indexed: 11/18/2022] Open
Abstract
RNA polymerase III (POLR3)-related leukodystrophy is an autosomal recessive form of leukodystrophy caused by homozygous or compound heterozygous mutations of the RNA polymerase III subunit genes, including subunit A (POLR3A). With respect to the manifestation triad, hypomyelination, hypodontia, and hypogonadotropic hypogonadism, it is also known as 4H leukodystrophy. Here, we report a 41-year-old woman of POLR3-related leukodystrophy by carrying compound heterozygous pathogenic variants of c.2554A>G (p.M852V) and c.2668G>T (p.V890F) in the POLR3A gene. She was amenorrheic and became a wheelchair user from the age of 15 years and suffered from multiple episodes of pathologic fractures, starting with a subtrochanteric fracture of the right femur after a tonic seizure at age 30 years. Head magnetic resonance imaging demonstrated hypomyelination and atrophies of the cerebellum, brainstem, and corpus callosum. Laboratory examination revealed a marked decrease of gonadotropins and estrogen, low bone density, and high bone resorption markers. Administration of anti-receptor activator of nuclear factor kappa-B ligand monoclonal antibody restored bone resorption markers to a normal level and prevented further pathological bone fractures. Our case emphasizes that osteoporosis should be recognized as a potential but serious complication in POLR3-related leukodystrophy. It may be feasible to prevent pathologic fractures by intensive osteoporosis therapy after endocrinological examinations and evaluation of bone metabolism.
Collapse
Affiliation(s)
- Soma Furukawa
- Department of Neurology, Toyota Memorial Hospital, Toyota, Japan.,Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Misako Kunii
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Hiroshi Doi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Naohide Kondo
- Department of Neurology, Toyota Memorial Hospital, Toyota, Japan.,Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan.,Wellness Promotion Center, Corporate Human Resource, Fuji Xerox Co., Ltd, Ebina, Japan
| | - Aya Ogura
- Department of Neurology, Toyota Memorial Hospital, Toyota, Japan.,Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | | | - Takayuki Itoh
- Faculty of Psychological and Physical Science, Aichi-Gakuin University, Nissin, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Fumiaki Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Masahisa Katsuno
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuhiro Ito
- Department of Neurology, Toyota Memorial Hospital, Toyota, Japan
| |
Collapse
|