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Khan D, Ramachandiran I, Vasu K, China A, Khan K, Cumbo F, Halawani D, Terenzi F, Zin I, Long B, Costain G, Blaser S, Carnevale A, Gogonea V, Dutta R, Blankenberg D, Yoon G, Fox PL. Homozygous EPRS1 missense variant causing hypomyelinating leukodystrophy-15 alters variant-distal mRNA m 6A site accessibility. Nat Commun 2024; 15:4284. [PMID: 38769304 PMCID: PMC11106242 DOI: 10.1038/s41467-024-48549-x] [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: 10/15/2023] [Accepted: 05/03/2024] [Indexed: 05/22/2024] Open
Abstract
Hypomyelinating leukodystrophy (HLD) is an autosomal recessive disorder characterized by defective central nervous system myelination. Exome sequencing of two siblings with severe cognitive and motor impairment and progressive hypomyelination characteristic of HLD revealed homozygosity for a missense single-nucleotide variant (SNV) in EPRS1 (c.4444 C > A; p.Pro1482Thr), encoding glutamyl-prolyl-tRNA synthetase, consistent with HLD15. Patient lymphoblastoid cell lines express markedly reduced EPRS1 protein due to dual defects in nuclear export and cytoplasmic translation of variant EPRS1 mRNA. Variant mRNA exhibits reduced METTL3 methyltransferase-mediated writing of N6-methyladenosine (m6A) and reduced reading by YTHDC1 and YTHDF1/3 required for efficient mRNA nuclear export and translation, respectively. In contrast to current models, the variant does not alter the sequence of m6A target sites, but instead reduces their accessibility for modification. The defect was rescued by antisense morpholinos predicted to expose m6A sites on target EPRS1 mRNA, or by m6A modification of the mRNA by METTL3-dCas13b, a targeted RNA methylation editor. Our bioinformatic analysis predicts widespread occurrence of SNVs associated with human health and disease that similarly alter accessibility of distal mRNA m6A sites. These results reveal a new RNA-dependent etiologic mechanism by which SNVs can influence gene expression and disease, consequently generating opportunities for personalized, RNA-based therapeutics targeting these disorders.
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Affiliation(s)
- Debjit Khan
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Iyappan Ramachandiran
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Kommireddy Vasu
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Arnab China
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Krishnendu Khan
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Fabio Cumbo
- Genomic Medicine Institute, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Dalia Halawani
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Fulvia Terenzi
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Isaac Zin
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
- Department of Chemistry, Cleveland State University, Cleveland, OH, USA
| | - Briana Long
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Gregory Costain
- Department of Paediatrics, Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Susan Blaser
- Department of Diagnostic Imaging, Division of Neuroradiology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Amanda Carnevale
- Department of Paediatrics, Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Valentin Gogonea
- Department of Chemistry, Cleveland State University, Cleveland, OH, USA
| | - Ranjan Dutta
- Department of Neuroscience, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Daniel Blankenberg
- Genomic Medicine Institute, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA
| | - Grace Yoon
- Department of Paediatrics, Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
- Department of Paediatrics, Division of Neurology, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
| | - Paul L Fox
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic, Lerner Research Institute, Cleveland, OH, USA.
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Gupta S, Jani J, Vijayasurya, Mochi J, Tabasum S, Sabarwal A, Pappachan A. Aminoacyl-tRNA synthetase - a molecular multitasker. FASEB J 2023; 37:e23219. [PMID: 37776328 DOI: 10.1096/fj.202202024rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 08/31/2023] [Accepted: 09/12/2023] [Indexed: 10/02/2023]
Abstract
Aminoacyl-tRNA synthetases (AaRSs) are valuable "housekeeping" enzymes that ensure the accurate transmission of genetic information in living cells, where they aminoacylated tRNA molecules with their cognate amino acid and provide substrates for protein biosynthesis. In addition to their translational or canonical function, they contribute to nontranslational/moonlighting functions, which are mediated by the presence of other domains on the proteins. This was supported by several reports which claim that AaRS has a significant role in gene transcription, apoptosis, translation, and RNA splicing regulation. Noncanonical/ nontranslational functions of AaRSs also include their roles in regulating angiogenesis, inflammation, cancer, and other major physio-pathological processes. Multiple AaRSs are also associated with a broad range of physiological and pathological processes; a few even serve as cytokines. Therefore, the multifunctional nature of AaRSs suggests their potential as viable therapeutic targets as well. Here, our discussion will encompass a range of noncanonical functions attributed to Aminoacyl-tRNA Synthetases (AaRSs), highlighting their links with a diverse array of human diseases.
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Affiliation(s)
- Swadha Gupta
- School of Life Sciences, Central University of Gujarat, Gandhinagar, India
| | - Jaykumar Jani
- School of Life Sciences, Central University of Gujarat, Gandhinagar, India
| | - Vijayasurya
- School of Life Sciences, Central University of Gujarat, Gandhinagar, India
| | - Jigneshkumar Mochi
- School of Life Sciences, Central University of Gujarat, Gandhinagar, India
| | - Saba Tabasum
- Dana Farber Cancer Institute, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Akash Sabarwal
- Harvard Medical School, Boston, Massachusetts, USA
- Boston Children's Hospital, Boston, Massachusetts, USA
| | - Anju Pappachan
- School of Life Sciences, Central University of Gujarat, Gandhinagar, India
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3
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Torii T, Yamauchi J. Molecular Pathogenic Mechanisms of Hypomyelinating Leukodystrophies (HLDs). Neurol Int 2023; 15:1155-1173. [PMID: 37755363 PMCID: PMC10538087 DOI: 10.3390/neurolint15030072] [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: 08/07/2023] [Revised: 08/29/2023] [Accepted: 09/06/2023] [Indexed: 09/28/2023] Open
Abstract
Hypomyelinating leukodystrophies (HLDs) represent a group of congenital rare diseases for which the responsible genes have been identified in recent studies. In this review, we briefly describe the genetic/molecular mechanisms underlying the pathogenesis of HLD and the normal cellular functions of the related genes and proteins. An increasing number of studies have reported genetic mutations that cause protein misfolding, protein dysfunction, and/or mislocalization associated with HLD. Insight into the mechanisms of these pathways can provide new findings for the clinical treatments of HLD.
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Affiliation(s)
- Tomohiro Torii
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji 192-0392, Japan
- Laboratory of Ion Channel Pathophysiology, Graduate School of Brain Science, Doshisha University, Kyotanabe-shi 610-0394, Japan
- Center for Research in Neurodegenerative Disease, Doshisha University, Kyotanabe-shi 610-0394, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji 192-0392, Japan
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya-ku 157-8535, Japan
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Tijaro-Bulla S, Nyandwi SP, Cui H. Physiological and engineered tRNA aminoacylation. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1789. [PMID: 37042417 DOI: 10.1002/wrna.1789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/11/2023] [Accepted: 03/21/2023] [Indexed: 04/13/2023]
Abstract
Aminoacyl-tRNA synthetases form the protein family that controls the interpretation of the genetic code, with tRNA aminoacylation being the key chemical step during which an amino acid is assigned to a corresponding sequence of nucleic acids. In consequence, aminoacyl-tRNA synthetases have been studied in their physiological context, in disease states, and as tools for synthetic biology to enable the expansion of the genetic code. Here, we review the fundamentals of aminoacyl-tRNA synthetase biology and classification, with a focus on mammalian cytoplasmic enzymes. We compile evidence that the localization of aminoacyl-tRNA synthetases can be critical in health and disease. In addition, we discuss evidence from synthetic biology which made use of the importance of subcellular localization for efficient manipulation of the protein synthesis machinery. This article is categorized under: RNA Processing Translation > Translation Regulation RNA Processing > tRNA Processing RNA Export and Localization > RNA Localization.
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Affiliation(s)
| | | | - Haissi Cui
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
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5
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CARNEIRO VF, MACHADO RA, BARBOSA MC, DIAS VO, MARTELLI DRB, MARTELLI-JÚNIOR H. Dental anomalies in syndromes displaying hypertrichosis in the clinical spectrum. Braz Oral Res 2023; 37:e030. [PMID: 37018811 DOI: 10.1590/1807-3107bor-2023.vol37.0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 09/19/2022] [Indexed: 04/05/2023] Open
Abstract
Hypertrichosis and dental anomalies may occur alone or in combination in the spectrum of many syndromes. To identify genetic entities characterized by hypertrichosis and dental anomalies, a search was performed in the Mendelian Inheritance in Man database with the terms "hypertrichosis" or "hirsutism" and "tooth" or "dental abnormalities." Nondependent androgen metabolism disturbances were classified as hypertrichosis. Genetic entities with hypertrichosis and dental anomalies were included in the study. Additional searches were performed in the PubMed and Orphanet databases, when necessary, in order to include data from scientific articles. An integrative analysis of the genes associated with the identified syndromes was conducted using STRING to characterize biological processes, pathways, and interactive networks. The p-values were subjected to the false discovery rate for the correction of multiple tests. Thirty-nine syndromes were identified, and dental agenesis was the most frequent dental anomaly present in 41.02% (n = 16) of the syndromes. Causative genes were identified in 33 out of 39 genetic syndromes. Among them, 39 genes were identified, and 38 were analyzed by STRING, which showed 148 biological processes and three pathways that were statistically significant. The most significant biological processes were the disassembly of the nucleosome (GO:0006337, p = 1.09e-06), chromosomal organization (GO:0051276, p = 1.09e-06) and remodeling of the chromatin (GO: 0006338, p = 7.86e-06), and the pathways were hepatocellular carcinoma (hsa05225, p = 5.77e-05), thermogenesis (hsa04714, p = 0.00019), and cell cycle (hsa04110, p = 0.0433). Our results showed that the identification of hypertrichosis and dental anomalies may raise the suspicion of one of the thirty-nine syndromes with both phenotypes.
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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.
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Yan H, Yang S, Hou Y, Ali S, Escobar A, Gao K, Duan R, Kubisiak T, Wang J, Zhang Y, Xiao J, Jiang Y, Zhang T, Wu Y, Burmeister M, Wang Q, Cuajungco MP, Wang J. Functional Study of TMEM163 Gene Variants Associated with Hypomyelination Leukodystrophy. Cells 2022; 11:cells11081285. [PMID: 35455965 PMCID: PMC9031525 DOI: 10.3390/cells11081285] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/19/2022] [Accepted: 04/06/2022] [Indexed: 02/06/2023] Open
Abstract
Hypomyelinating leukodystrophies (HLDs) are a rare group of heterogeneously genetic disorders characterized by persistent deficit of myelin observed on magnetic resonance imaging (MRI). To identify a new disease-associated gene of HLD, trio-based whole exome sequencing was performed for unexplained patients with HLD. Functional studies were performed to confirm the phenotypic effect of candidate protein variants. Two de novo heterozygous variants, c.227T>G p.(L76R) or c.227T>C p.(L76P) in TMEM163 were identified in two unrelated HLD patients. TMEM163 protein is a zinc efflux transporter localized within the plasma membrane, lysosomes, early endosomes, and other vesicular compartments. It has not been associated with hypomyelination. Functional zinc flux assays in HeLa cells stably-expressing TMEM163 protein variants, L76R and L76P, revealed distinct attenuation or enhancement of zinc efflux, respectively. Experiments using a zebrafish model with knockdown of tmem163a and tmem163b (morphants) showed that loss of tmem163 causes dysplasia of the larvae, locomotor disability and myelin deficit. Expression of human wild type TMEM163 mRNAs in morphants rescues the phenotype, while the TMEM163 L76P and L76R mutants aggravated the condition. Moreover, poor proliferation, elevated apoptosis of oligodendrocytes, and reduced oligodendrocytes and neurons were also observed in zebrafish morphants. Our findings suggest an unappreciated role for TMEM163 protein in myelin development and add TMEM163 to a growing list of genes associated with hypomyelination leukodystrophy.
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Affiliation(s)
- Huifang Yan
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China; (H.Y.); (K.G.); (R.D.); (J.W.); (Y.Z.); (Y.J.); (Y.W.)
- Joint International Research Center of Translational and Clinical Research, Beijing 100191, China
- Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing 100034, China
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA; (T.K.); (M.B.)
| | - Shuyan Yang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China; (S.Y.); (T.Z.)
| | - Yiming Hou
- State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China; (Y.H.); (Q.W.)
| | - Saima Ali
- Department of Biological Science, California State University, Fullerton, CA 92831, USA; (S.A.); (A.E.)
| | - Adrian Escobar
- Department of Biological Science, California State University, Fullerton, CA 92831, USA; (S.A.); (A.E.)
| | - Kai Gao
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China; (H.Y.); (K.G.); (R.D.); (J.W.); (Y.Z.); (Y.J.); (Y.W.)
| | - Ruoyu Duan
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China; (H.Y.); (K.G.); (R.D.); (J.W.); (Y.Z.); (Y.J.); (Y.W.)
| | - Thomas Kubisiak
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA; (T.K.); (M.B.)
| | - Junyu Wang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China; (H.Y.); (K.G.); (R.D.); (J.W.); (Y.Z.); (Y.J.); (Y.W.)
| | - Yu Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China; (H.Y.); (K.G.); (R.D.); (J.W.); (Y.Z.); (Y.J.); (Y.W.)
| | - Jiangxi Xiao
- Department of Radiology, Peking University First Hospital, Beijing 100034, China;
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China; (H.Y.); (K.G.); (R.D.); (J.W.); (Y.Z.); (Y.J.); (Y.W.)
- Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing 100034, China
- Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing 100191, China
| | - Ting Zhang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China; (S.Y.); (T.Z.)
| | - Ye Wu
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China; (H.Y.); (K.G.); (R.D.); (J.W.); (Y.Z.); (Y.J.); (Y.W.)
- Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing 100034, China
| | - Margit Burmeister
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA; (T.K.); (M.B.)
- Departments of Computational Medicine & Bioinformatics, Psychiatry and Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Qiang Wang
- State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100101, China; (Y.H.); (Q.W.)
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Math P. Cuajungco
- Department of Biological Science, California State University, Fullerton, CA 92831, USA; (S.A.); (A.E.)
- Center for Applied Biotechnology Studies, California State University, Fullerton, CA 92831, USA
- Correspondence: (M.P.C.); (J.W.)
| | - Jingmin Wang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China; (H.Y.); (K.G.); (R.D.); (J.W.); (Y.Z.); (Y.J.); (Y.W.)
- Joint International Research Center of Translational and Clinical Research, Beijing 100191, China
- Beijing Key Laboratory of Molecular Diagnosis and Study on Pediatric Genetic Diseases, Beijing 100034, China
- Key Laboratory for Neuroscience, Ministry of Education/National Health and Family Planning Commission, Peking University, Beijing 100191, China
- Correspondence: (M.P.C.); (J.W.)
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8
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Khan K, Gogonea V, Fox PL. Aminoacyl-tRNA synthetases of the multi-tRNA synthetase complex and their role in tumorigenesis. Transl Oncol 2022; 19:101392. [PMID: 35278792 PMCID: PMC8914993 DOI: 10.1016/j.tranon.2022.101392] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/27/2022] [Accepted: 02/28/2022] [Indexed: 12/16/2022] Open
Abstract
In mammalian cells, 20 aminoacyl-tRNA synthetases (AARS) catalyze the ligation of amino acids to their cognate tRNAs to generate aminoacylated-tRNAs. In higher eukaryotes, 9 of the 20 AARSs, along with 3 auxiliary proteins, join to form the cytoplasmic multi-tRNA synthetase complex (MSC). The complex is absent in prokaryotes, but evolutionary expansion of MSC constituents, primarily by addition of novel interacting domains, facilitates formation of subcomplexes that join to establish the holo-MSC. In some cases, environmental cues direct the release of constituents from the MSC which enables the execution of non-canonical, i.e., "moonlighting", functions distinct from their essential activities in protein translation. These activities are generally beneficial, but can also be deleterious to the cell. Elucidation of the non-canonical activities of several AARSs residing in the MSC suggest they are potential therapeutic targets for cancer, as well as metabolic and neurologic diseases. Here, we describe the role of MSC-resident AARSs in cancer progression, and the factors that regulate their release from the MSC. Also, we highlight recent developments in therapeutic modalities that target MSC AARSs for cancer prevention and treatment.
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Affiliation(s)
- Krishnendu Khan
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States of America.
| | - Valentin Gogonea
- Department of Chemistry, Cleveland State University, Cleveland, OH 44115, United States of America
| | - Paul L Fox
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, United States of America.
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Mazaheri M, Yavari M, Zare Marzouni H, Stufano A, Lovreglio P, D'Amore S, Jahantigh HR. Case Report: Mutation in AIMP2/P38, the Scaffold for the Multi-Trna Synthetase Complex, and Association With Progressive Neurodevelopmental Disorders. Front Genet 2022; 13:816987. [PMID: 35140751 PMCID: PMC8820504 DOI: 10.3389/fgene.2022.816987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/04/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Leukodystrophies constitute a heterogeneous group of inherited disorders primarily affecting the white matter of the central nervous system. Aminoacyl-tRNA synthetases (ARSs) catalyze the attachment of an amino acids to their cognate transfer RNAs (tRNAs). Pathogenic variants in both cytosolic and mitochondrial ARSs have been linked to a broad range of neurological disorders, including hypomyelinating leukodystrophies and pontocerebellar hypoplasias (PCH). Aminoacyl tRNA synthetase-interacting multifunctional protein 2 (AIMP2), one of the three non-catalytic components of multi ARS complex, harbors anti-proliferative activity and functions as a proapoptotic factor thus promoting cell death. We report a case of a 7-month-old infant with a complex clinical presentation, including weight loss, severe anemia, skeletal abnormalities, microcephaly and MR imaging features of leukodystrophy with a novel mutation in AIMP2.Methods: Whole-exome sequencing (WES) was performed on the proband. Parental samples were analyzed by PCR amplification and Sanger sequencing.Results: Whole-exome sequencing revealed a novel variant c.A463T in the homozygous state in exon 3 (NM_001,326,607) of AIMP2 [p.(K155X)] in the proband. Parental carrier status was confirmed by target sequencing.Conclusion: Here, we present an Iranian case with leukodystrophy with a novel AIMP2 mutation. This finding broadens the mutational and phenotypic spectra of AIMP2-related leukodystrophy and offers guidance for proper genetic counselling for pre- and post-natal screenings as well as for disease management.
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Affiliation(s)
- Mahta Mazaheri
- Department of Medical Genetics, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
- Mother and Newborn Health Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
- Dr. Mazaheri’s Medical Genetics Lab, Yazd, Iran
| | - Mahdie Yavari
- Dr. Mazaheri’s Medical Genetics Lab, Yazd, Iran
- Division of Genetics, Department of Cell and Molecular Biology and Microbiology, Faculty of Science and Biotechnology, University of Isfahan, Isfahan, Iran
| | - Hadi Zare Marzouni
- Qaen School of Nursing and Midwifery, Birjand University of Medical Sciences, Birjand, Iran
| | - Angela Stufano
- Department of Veterinary Medicine, University of Bari Aldo Moro, Bari, Italy
- Interdisciplinary Department of Medicine - Section of Occupational Medicine, University of Bari, Bari, Italy
- *Correspondence: Angela Stufano,
| | - Piero Lovreglio
- Interdisciplinary Department of Medicine - Section of Occupational Medicine, University of Bari, Bari, Italy
| | - Simona D'Amore
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Hamid Reza Jahantigh
- Department of Veterinary Medicine, University of Bari Aldo Moro, Bari, Italy
- Interdisciplinary Department of Medicine - Section of Occupational Medicine, University of Bari, Bari, Italy
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Giong HK, Lee JS. Systematic expression profiling of neuropathy-related aminoacyl-tRNA synthetases in zebrafish during development. Biochem Biophys Res Commun 2022; 587:92-98. [PMID: 34872004 DOI: 10.1016/j.bbrc.2021.11.098] [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: 10/22/2021] [Accepted: 11/27/2021] [Indexed: 12/01/2022]
Abstract
Aminoacyl tRNA synthetases (ARSs) are a group of proteins, acting as transporters to transfer and attach the appropriate amino acids onto their cognate tRNAs for translation. So far, 18 out of 20 cytoplasmic ARSs are reported to be connected to different neuropathy disorders with multi-organ defects that are often accompanied with developmental delays. Thus, it is important to understand functions and impacts of ARSs at the whole organism level. Here, we systematically analyzed the spatiotemporal expression of 14 ars and 2 aimp genes during development in zebrafish that have not be previously reported. Not only in the brain, their dynamic expression patterns in several tissues such as in the muscles, liver and intestine suggest diverse roles in a wide range of development processes in addition to neuronal function, which is consistent with potential involvement in multiple syndrome diseases associated with ARS mutations. In particular, hinted by its robust expression pattern in the brain, we confirmed that aimp1 is required for the formation of cerebrovasculature by a loss-of-function approach. Overall, our systematic profiling data provides a useful basis for studying roles of ARSs during development and understanding their potential functions in the etiology of related diseases.
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Affiliation(s)
- Hoi-Khoanh Giong
- Disease Target Structure Research Center, KRIBB, Daejeon, South Korea; KRIBB School, University of Science and Technology, Daejeon, South Korea; Dementia DTC R&D Convergence Program, KIST, Seoul, South Korea
| | - Jeong-Soo Lee
- Disease Target Structure Research Center, KRIBB, Daejeon, South Korea; KRIBB School, University of Science and Technology, Daejeon, South Korea; Dementia DTC R&D Convergence Program, KIST, Seoul, South Korea.
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Kaur P, do Rosario MC, Hebbar M, Sharma S, Kausthubham N, Nair K, Shrikiran A, Bhat Y R, Lewis LES, Nampoothiri S, Patil SJ, Suresh N, Bijarnia Mahay S, Dua Puri R, Pai S, Kaur A, KC R, Kamath N, Bajaj S, Kumble A, Shetty R, Shenoy R, Kamate M, Shah H, Muranjan MN, BL Y, Avabratha KS, Subramaniam G, Kadavigere R, Bielas S, Girisha KM, Shukla A. Clinical and genetic spectrum of 104 Indian families with central nervous system white matter abnormalities. Clin Genet 2021; 100:542-550. [PMID: 34302356 PMCID: PMC8918360 DOI: 10.1111/cge.14037] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/19/2021] [Accepted: 07/20/2021] [Indexed: 12/15/2022]
Abstract
Genetic disorders with predominant central nervous system white matter abnormalities (CNS WMAs), also called leukodystrophies, are heterogeneous entities. We ascertained 117 individuals with CNS WMAs from 104 unrelated families. Targeted genetic testing was carried out in 16 families and 13 of them received a diagnosis. Chromosomal microarray (CMA) was performed for three families and one received a diagnosis. Mendeliome sequencing was used for testing 11 families and all received a diagnosis. Whole exome sequencing (WES) was performed in 80 families and was diagnostic in 52 (65%). Singleton WES was diagnostic for 50/75 (66.67%) families. Overall, genetic diagnoses were obtained in 77 families (74.03%). Twenty-two of 47 distinct disorders observed in this cohort have not been reported in Indian individuals previously. Notably, disorders of nuclear mitochondrial pathology were most frequent (9 disorders in 20 families). Thirty-seven of 75 (49.33%) disease-causing variants are novel. To sum up, the present cohort describes the phenotypic and genotypic spectrum of genetic disorders with CNS WMAs in our population. It demonstrates WES, especially singleton WES, as an efficient tool in the diagnosis of these heterogeneous entities. It also highlights possible founder events and recurrent disease-causing variants in our population and their implications on the testing strategy.
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Affiliation(s)
- Parneet Kaur
- Department of Medical Genetics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Michelle C do Rosario
- Department of Medical Genetics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Malavika Hebbar
- Department of Medical Genetics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Suvasini Sharma
- Department of Paediatrics, Lady Hardinge Medical College and Associated Kalawati Saran Children’s Hospital, New Delhi, India
| | - Neethukrishna Kausthubham
- Department of Medical Genetics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Karthik Nair
- Department of Medical Genetics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - A Shrikiran
- Department of Paediatrics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Ramesh Bhat Y
- Department of Paediatrics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Leslie Edward S Lewis
- Department of Paediatrics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Sheela Nampoothiri
- Department of Paediatric Genetics, Amrita Institute of Medical Sciences and Research Centre, Kochi, India
| | - SJ Patil
- Division of Genetics, Mazumdar Shaw Medical Centre, Narayana Health City, Bangalore, India
| | - Narayanaswami Suresh
- Department of Paediatrics, Lady Hardinge Medical College and Associated Kalawati Saran Children’s Hospital, New Delhi, India
| | - Sunita Bijarnia Mahay
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi, India
| | - Ratna Dua Puri
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi, India
| | - Shivanand Pai
- Department of Neurology, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, India
| | - Anupriya Kaur
- Department of Paediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Rakshith KC
- Department of Neurology, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, India
| | - Nutan Kamath
- Department of Paediatrics, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, India
| | - Shruti Bajaj
- Jaslok Hospital and Research Centre, Mumbai, India
| | - Ali Kumble
- Department of Paediatrics, Indiana Hospital and Heart Institute, Mangalore, India
| | | | - Rathika Shenoy
- Department of Paediatrics, K.S. Hegde Medical Academy, NITTE University, Mangalore, India
| | - Mahesh Kamate
- Department of Paediatrics, Jawaharlal Nehru Medical College, Belgaum, India
| | - Hitesh Shah
- Department of Orthopaedics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Mamta N Muranjan
- Department of Pediatrics, Genetics Division, Seth Gordhandas Sunderdas Medical College and King Edward VII Memorial Hospital, Parel, Mumbai, Maharashtra, India
| | - Yatheesha BL
- Dheemahi Child Neurology and Development Center, Shimoga, India
| | | | | | - Rajagopal Kadavigere
- Department of Radiodiagnosis, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Stephanie Bielas
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Katta Mohan Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Anju Shukla
- Department of Medical Genetics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
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12
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Knockdown of Golgi Stress-Responsive Caspase-2 Ameliorates HLD17-Associated AIMP2 Mutant-Mediated Inhibition of Oligodendroglial Cell Morphological Differentiation. Neurochem Res 2021; 47:2617-2631. [PMID: 34523057 DOI: 10.1007/s11064-021-03451-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 10/20/2022]
Abstract
Hypomyelinating leukodystrophy 17 is an autosomal recessive disease affecting myelin-forming oligodendroglial cells in the central nervous system. The gene responsible for HLD17 encodes aminoacyl-tRNA synthase complex-interacting multifunctional protein 2, whose product proteins form a scaffold that supports aminoacyl-tRNA synthetases throughout the cell body. Here we show that the HLD17-associated nonsense mutation (Tyr35-to-Ter [Y35X]) of AIMP2 localizes AIMP2 proteins as aggregates into the Golgi bodies in mouse oligodendroglial FBD-102b cells. Wild type AIMP2 proteins, in contrast, are distributed throughout the cell body. Expression of the Y35X mutant proteins, but not the wild type proteins, in cells upregulates Golgi stress signaling involving caspase-2 activation. Cells expressing the wild type proteins exhibit differentiated phenotypes with web-like structures bearing many processes following the induction of differentiation, whereas cells expressing the Y35X mutant proteins fail to differentiate. Furthermore, CASP2 knockdown but not control knockdown reverses the phenotypes of cells expressing the mutant proteins. These results suggest that HLD17-associated AIMP2 mutant proteins are localized in the Golgi bodies where their proteins stimulate Golgi stress-responsive CASP2 to inhibit differentiation; this effect is ameliorated by knockdown of CASP2. These findings may reveal some of the molecular and cellular pathological mechanisms underlying HLD17 and possible approaches to ameliorating the disease's effects.
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13
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Kausthubham N, Shukla A, Gupta N, Bhavani GS, Kulshrestha S, Das Bhowmik A, Moirangthem A, Bijarnia-Mahay S, Kabra M, Puri RD, Mandal K, Verma IC, Bielas SL, Phadke SR, Dalal A, Girisha KM. A data set of variants derived from 1455 clinical and research exomes is efficient in variant prioritization for early-onset monogenic disorders in Indians. Hum Mutat 2021; 42:e15-e61. [PMID: 33502066 PMCID: PMC10052794 DOI: 10.1002/humu.24172] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/05/2021] [Accepted: 01/24/2021] [Indexed: 12/16/2022]
Abstract
Given the genomic uniqueness, a local data set is most desired for Indians, who are underrepresented in existing public databases. We hypothesize patients with rare monogenic disorders and their family members can provide a reliable source of common variants in the population. Exome sequencing (ES) data from families with rare Mendelian disorders was aggregated from five centers in India. The dataset was refined by excluding related individuals and removing the disease-causing variants (refined cohort). The efficiency of these data sets was assessed in a new set of 50 exomes against gnomAD and GenomeAsia. Our original cohort comprised 1455 individuals from 1203 families. The refined cohort had 836 unrelated individuals that retained 1,251,064 variants with 181,125 population-specific and 489,618 common variants. The allele frequencies from our cohort helped to define 97,609 rare variants in gnomAD and 44,520 rare variants in GenomeAsia as common variants in our population. Our variant dataset provided an additional 1.7% and 0.1% efficiency for prioritizing heterozygous and homozygous variants respectively for rare monogenic disorders. We observed additional 19 genes/human knockouts. We list carrier frequency for 142 recessive disorders. This is a large and useful resource of exonic variants for Indians. Despite limitations, datasets from patients are efficient tools for variant prioritization in a resource-limited setting.
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Affiliation(s)
- Neethukrishna Kausthubham
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Anju Shukla
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Neerja Gupta
- Division of Genetics, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Gandham S Bhavani
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Samarth Kulshrestha
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi, India
| | - Aneek Das Bhowmik
- Division of Diagnostics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India.,ASPIRE (Diagnostics Facility), CSIR-Centre for Cellular & Molecular Biology, CCMB Annexe II, Hyderabad, India
| | - Amita Moirangthem
- Department of Medical Genetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Sunita Bijarnia-Mahay
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi, India
| | - Madhulika Kabra
- Division of Genetics, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Ratna D Puri
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi, India
| | - Kausik Mandal
- Department of Medical Genetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Ishwar C Verma
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, New Delhi, India
| | - Stephanie L Bielas
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Shubha R Phadke
- Department of Medical Genetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Ashwin Dalal
- Division of Diagnostics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Katta M Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
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14
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Khan K, Baleanu-Gogonea C, Willard B, Gogonea V, Fox PL. 3-Dimensional architecture of the human multi-tRNA synthetase complex. Nucleic Acids Res 2020; 48:8740-8754. [PMID: 32644155 PMCID: PMC7470956 DOI: 10.1093/nar/gkaa569] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/08/2020] [Accepted: 07/06/2020] [Indexed: 11/24/2022] Open
Abstract
In mammalian cells, eight cytoplasmic aminoacyl-tRNA synthetases (AARS), and three non-synthetase proteins, reside in a large multi-tRNA synthetase complex (MSC). AARSs have critical roles in interpretation of the genetic code during protein synthesis, and in non-canonical functions unrelated to translation. Nonetheless, the structure and function of the MSC remain unclear. Partial or complete crystal structures of all MSC constituents have been reported; however, the structure of the holo-MSC has not been resolved. We have taken advantage of cross-linking mass spectrometry (XL-MS) and molecular docking to interrogate the three-dimensional architecture of the MSC in human HEK293T cells. The XL-MS approach uniquely provides structural information on flexibly appended domains, characteristic of nearly all MSC constituents. Using the MS-cleavable cross-linker, disuccinimidyl sulfoxide, inter-protein cross-links spanning all MSC constituents were observed, including cross-links between eight protein pairs not previously known to interact. Intra-protein cross-links defined new structural relationships between domains in several constituents. Unexpectedly, an asymmetric AARS distribution was observed featuring a clustering of tRNA anti-codon binding domains on one MSC face. Possibly, the non-uniform localization improves efficiency of delivery of charged tRNA’s to an interacting ribosome during translation. In summary, we show a highly compact, 3D structural model of the human holo-MSC.
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Affiliation(s)
- Krishnendu Khan
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | | | - Belinda Willard
- Lerner Research Institute Proteomics and Metabolomics Core, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Valentin Gogonea
- Department of Chemistry, Cleveland State University, Cleveland, OH 44115, USA
| | - Paul L Fox
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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15
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Girisha KM, Pande S, Dalal A, Phadke SR. Untapped opportunities for rare disease gene discovery in India. Am J Med Genet A 2020; 182:3056-3059. [PMID: 32914504 DOI: 10.1002/ajmg.a.61866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 08/22/2020] [Indexed: 11/08/2022]
Affiliation(s)
- Katta Mohan Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Shruti Pande
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Ashwin Dalal
- Diagnostics Division, Center for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Shubha R Phadke
- Department of Medical Genetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
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16
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Roles of aminoacyl-tRNA synthetase-interacting multi-functional proteins in physiology and cancer. Cell Death Dis 2020; 11:579. [PMID: 32709848 PMCID: PMC7382500 DOI: 10.1038/s41419-020-02794-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 07/03/2020] [Accepted: 07/06/2020] [Indexed: 12/15/2022]
Abstract
Aminoacyl-tRNA synthetases (ARSs) are an important class of enzymes with an evolutionarily conserved mechanism for protein synthesis. In higher eukaryotic systems, eight ARSs and three ARS-interacting multi-functional proteins (AIMPs) form a multi-tRNA synthetase complex (MSC), which seems to contribute to cellular homeostasis. Of these, AIMPs are generally considered as non-enzyme factors, playing a scaffolding role during MSC assembly. Although the functions of AIMPs are not fully understood, increasing evidence indicates that these scaffold proteins usually exert tumor-suppressive activities. In addition, endothelial monocyte-activating polypeptide II (EMAP II), as a cleavage product of AIMP1, and AIMP2-DX2, as a splice variant of AIMP2 lacking exon 2, also have a pivotal role in regulating tumorigenesis. In this review, we summarize the biological functions of AIMP1, EMAP II, AIMP2, AIMP2-DX2, and AIMP3. Also, we systematically introduce their emerging roles in cancer, aiming to provide new ideas for the treatment of cancer.
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17
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Malik P, Muthusamy K, Mankad K, Shroff M, Sudhakar S. Solving the hypomyelination conundrum - Imaging perspectives. Eur J Paediatr Neurol 2020; 27:9-24. [PMID: 32418752 DOI: 10.1016/j.ejpn.2020.04.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 03/25/2020] [Accepted: 04/14/2020] [Indexed: 11/26/2022]
Abstract
Hypomyelinating Leukodystrophies (HLDs) are a genetically heterogeneous, clinically overlapping group of disorders with the unifying MR imaging appearance of myelin deficit in the brain. In fact, it is the MRI phenotype that typically raises the diagnostic suspicion in this single largest group of undiagnosed leukodystrophies and guides gene testing for confirmation. This article reviews the neurobiology of myelination, focussing on the complex interplay of molecular genetic pathways and presents a practical clinico-radiological diagnostic algorithm based on the neuroimaging patterns of the common hypomyelinating disorders. The authors also address the current controversies about the definition and use of the term 'hypomyelination'.
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18
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Li HY, Fang JX, Zou CC. Clinical Features of Patients With 7p22.1 Microdeletion. Indian Pediatr 2020. [DOI: 10.1007/s13312-020-1865-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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19
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Kim DG, Nguyen TTH, Kwon NH, Sung J, Lim S, Kang EJ, Lee J, Seo WY, Kim A, Chang YS, Shim H, Kim S. An Isoform of the Oncogenic Splice Variant AIMP2-DX2 Detected by a Novel Monoclonal Antibody. Biomolecules 2020; 10:biom10060820. [PMID: 32471182 PMCID: PMC7356629 DOI: 10.3390/biom10060820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 11/16/2022] Open
Abstract
AIMP2-DX2, an exon 2-deleted splice variant of AIMP2 (aminoacyl-tRNA synthetase-interacting multifunctional protein 2), is highly expressed in lung cancer and involved in tumor progression in vivo. Oncogenic function of AIMP2-DX2 and its correlation with poor prognosis of cancer patients have been well established; however, the application of this potentially important biomarker to cancer research and diagnosis has been hampered by a lack of antibodies specific for the splice variant, possibly due to the poor immunogenicity and/or stability of AIMP2-DX2. In this study a monoclonal antibody, H5, that specifically recognizes AIMP2-DX2 and its isoforms was generated via rabbit immunization and phage display techniques, using a short peptide corresponding to the exon 1/3 junction sequence as an antigen. Furthermore, based on mutagenesis, limited cleavage, and mass spectrometry studies, it is also suggested that the endogenous isoform of AIMP2-DX2 recognized by H5 is produced by proteolytic cleavage of 33 amino acids from N-terminus and is capable of inducing cell proliferation similarly to the uncleaved protein. H5 monoclonal antibody is applicable to enzyme-linked immunosorbent assay, immunoblot, immunofluorescence, and immunohistochemistry, and expected to be a valuable tool for detecting AIMP2-DX2 with high sensitivity and specificity for research and diagnostic purposes.
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Affiliation(s)
- Dae Gyu Kim
- Medicinal Bioconvergence Research Center, College of Pharmacy and College of Medicine, Gangnam Severance Hospital, Yonsei University, Incheon 21983, Korea; (D.G.K.); (N.H.K.); (J.S.); (S.L.); (E.-J.K.); (J.L.); (W.Y.S.)
| | - Thi Thu Ha Nguyen
- Department of Life Science, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 03760, Korea;
| | - Nam Hoon Kwon
- Medicinal Bioconvergence Research Center, College of Pharmacy and College of Medicine, Gangnam Severance Hospital, Yonsei University, Incheon 21983, Korea; (D.G.K.); (N.H.K.); (J.S.); (S.L.); (E.-J.K.); (J.L.); (W.Y.S.)
| | - Junsik Sung
- Medicinal Bioconvergence Research Center, College of Pharmacy and College of Medicine, Gangnam Severance Hospital, Yonsei University, Incheon 21983, Korea; (D.G.K.); (N.H.K.); (J.S.); (S.L.); (E.-J.K.); (J.L.); (W.Y.S.)
| | - Semi Lim
- Medicinal Bioconvergence Research Center, College of Pharmacy and College of Medicine, Gangnam Severance Hospital, Yonsei University, Incheon 21983, Korea; (D.G.K.); (N.H.K.); (J.S.); (S.L.); (E.-J.K.); (J.L.); (W.Y.S.)
| | - Eun-Joo Kang
- Medicinal Bioconvergence Research Center, College of Pharmacy and College of Medicine, Gangnam Severance Hospital, Yonsei University, Incheon 21983, Korea; (D.G.K.); (N.H.K.); (J.S.); (S.L.); (E.-J.K.); (J.L.); (W.Y.S.)
| | - Jihye Lee
- Medicinal Bioconvergence Research Center, College of Pharmacy and College of Medicine, Gangnam Severance Hospital, Yonsei University, Incheon 21983, Korea; (D.G.K.); (N.H.K.); (J.S.); (S.L.); (E.-J.K.); (J.L.); (W.Y.S.)
| | - Woo Young Seo
- Medicinal Bioconvergence Research Center, College of Pharmacy and College of Medicine, Gangnam Severance Hospital, Yonsei University, Incheon 21983, Korea; (D.G.K.); (N.H.K.); (J.S.); (S.L.); (E.-J.K.); (J.L.); (W.Y.S.)
| | - Arum Kim
- Department of Internal Medicine, Yonsei University College of Medicine, 63 Gil-20, Eonju-ro, Gangnam-gu, Seoul 06229, Korea; (A.K.); (Y.S.C.)
| | - Yoon Soo Chang
- Department of Internal Medicine, Yonsei University College of Medicine, 63 Gil-20, Eonju-ro, Gangnam-gu, Seoul 06229, Korea; (A.K.); (Y.S.C.)
| | - Hyunbo Shim
- Department of Life Science, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul 03760, Korea;
- Correspondence: (H.S.); (S.K.)
| | - Sunghoon Kim
- Medicinal Bioconvergence Research Center, College of Pharmacy and College of Medicine, Gangnam Severance Hospital, Yonsei University, Incheon 21983, Korea; (D.G.K.); (N.H.K.); (J.S.); (S.L.); (E.-J.K.); (J.L.); (W.Y.S.)
- Correspondence: (H.S.); (S.K.)
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20
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Takeuchi Y, Tanaka M, Okura N, Fukui Y, Noguchi K, Hayashi Y, Torii T, Ooizumi H, Ohbuchi K, Mizoguchi K, Miyamoto Y, Yamauchi J. Rare Neurologic Disease-Associated Mutations of AIMP1 are Related with Inhibitory Neuronal Differentiation Which is Reversed by Ibuprofen. MEDICINES 2020; 7:medicines7050025. [PMID: 32384815 PMCID: PMC7281511 DOI: 10.3390/medicines7050025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/01/2020] [Accepted: 05/04/2020] [Indexed: 01/04/2023]
Abstract
Background: Hypomyelinating leukodystrophy 3 (HLD3), previously characterized as a congenital diseases associated with oligodendrocyte myelination, is increasingly regarded as primarily affecting neuronal cells. Methods: We used N1E-115 cells as the neuronal cell model to investigate whether HLD3-associated mutant proteins of cytoplasmic aminoacyl-tRNA synthase complex-interacting multifunctional protein 1 (AIMP1) aggregate in organelles and affect neuronal differentiation. Results: 292CA frame-shift type mutant proteins harboring a two-base (CA) deletion at the 292th nucleotide are mainly localized in the lysosome where they form aggregates. Similar results are observed in mutant proteins harboring the Gln39-to-Ter (Q39X) mutation. Interestingly, the frame-shift mutant-specific peptide specifically interacts with actin to block actin fiber formation. The presence of actin with 292CA mutant proteins, but not with wild type or Q39X ones, in the lysosome is detectable by immunoprecipitation of the lysosome. Furthermore, expression of 292CA or Q39X mutants in cells inhibits neuronal differentiation. Treatment with ibuprofen reverses mutant-mediated inhibitory differentiation as well as the localization in the lysosome. Conclusions: These results not only explain the cell pathological mechanisms inhibiting phenotype differentiation in cells expressing HLD3-associated mutants but also identify the first chemical that restores such cells in vitro.
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Affiliation(s)
- Yu Takeuchi
- Laboratory of Molecular Neuroscience and Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (Y.T.); (M.T.); (N.O.); (Y.F.); (Y.M.)
| | - Marina Tanaka
- Laboratory of Molecular Neuroscience and Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (Y.T.); (M.T.); (N.O.); (Y.F.); (Y.M.)
| | - Nanako Okura
- Laboratory of Molecular Neuroscience and Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (Y.T.); (M.T.); (N.O.); (Y.F.); (Y.M.)
| | - Yasuyuki Fukui
- Laboratory of Molecular Neuroscience and Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (Y.T.); (M.T.); (N.O.); (Y.F.); (Y.M.)
| | - Ko Noguchi
- Laboratory of Applied Ecology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan;
| | - Yoshihiro Hayashi
- Laboratory of Oncology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan;
| | - Tomohiro Torii
- Laboratory of Ion Channel Pathophysiology, Doshisha University, Kyotanabe, Kyoto 610-0394, Japan;
| | - Hiroaki Ooizumi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki, Ibaraki 200-1192, Japan; (H.O.); (K.O.); (K.M.)
| | - Katsuya Ohbuchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki, Ibaraki 200-1192, Japan; (H.O.); (K.O.); (K.M.)
| | - Kazushige Mizoguchi
- Tsumura Research Laboratories, Tsumura & Co., Inashiki, Ibaraki 200-1192, Japan; (H.O.); (K.O.); (K.M.)
| | - Yuki Miyamoto
- Laboratory of Molecular Neuroscience and Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (Y.T.); (M.T.); (N.O.); (Y.F.); (Y.M.)
- Laboratory of Molecular Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neuroscience and Neurology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan; (Y.T.); (M.T.); (N.O.); (Y.F.); (Y.M.)
- Laboratory of Molecular Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan
- Correspondence: ; Tel.: (+81)-42-676-7164
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Abstract
Aminoacyl-tRNA synthetases (ARSs) are essential enzymes for protein synthesis with evolutionarily conserved enzymatic mechanisms. Despite their similarity across organisms, scientists have been able to generate effective anti-infective agents based on the structural differences in the catalytic clefts of ARSs from pathogens and humans. However, recent genomic, proteomic and functionomic advances have unveiled unexpected disease-associated mutations and altered expression, secretion and interactions in human ARSs, revealing hidden biological functions beyond their catalytic roles in protein synthesis. These studies have also brought to light their potential as a rich and unexplored source for new therapeutic targets and agents through multiple avenues, including direct targeting of the catalytic sites, controlling disease-associated protein-protein interactions and developing novel biologics from the secreted ARS proteins or their parts. This Review addresses the emerging biology and therapeutic applications of human ARSs in diseases including autoimmune and rare diseases, and cancer.
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Mendes MI, Green LMC, Bertini E, Tonduti D, Aiello C, Smith D, Salsano E, Beerepoot S, Hertecant J, von Spiczak S, Livingston JH, Emrick L, Fraser J, Russell L, Bernard G, Magri S, Di Bella D, Taroni F, Koenig MK, Moroni I, Cappuccio G, Brunetti‐Pierri N, Rhee J, Mendelsohn BA, Helbig I, Helbig K, Muhle H, Ismayl O, Vanderver AL, Salomons GS, van der Knaap MS, Wolf NI. RARS1-related hypomyelinating leukodystrophy: Expanding the spectrum. Ann Clin Transl Neurol 2020; 7:83-93. [PMID: 31814314 PMCID: PMC6952319 DOI: 10.1002/acn3.50960] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 11/09/2019] [Accepted: 11/14/2019] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE Biallelic variants in RARS1, encoding the cytoplasmic tRNA synthetase for arginine (ArgRS), cause a hypomyelinating leukodystrophy. This study aimed to investigate clinical, neuroradiological and genetic features of patients with RARS1-related disease, and to identify possible genotype-phenotype relationships. METHODS We performed a multinational cross-sectional survey among 20 patients with biallelic RARS1 variants identified by next-generation sequencing techniques. Clinical data, brain MRI findings and genetic results were analyzed. Additionally, ArgRS activity was measured in fibroblasts of four patients, and translation of long and short ArgRS isoforms was quantified by western blot. RESULTS Clinical presentation ranged from severe (onset in the first 3 months, usually with refractory epilepsy and early brain atrophy), to intermediate (onset in the first year with nystagmus and spasticity), and mild (onset around or after 12 months with minimal cognitive impairment and preserved independent walking). The most frequent RARS1 variant, c.5A>G, led to mild or intermediate phenotypes, whereas truncating variants and variants affecting amino acids close to the ArgRS active centre led to severe phenotypes. ArgRS activity was significantly reduced in three patients with intermediate and severe phenotypes; in a fourth patient with intermediate to severe presentation, we measured normal ArgRS activity, but found translation mainly of the short instead of the long ArgRS isoform. INTERPRETATION Variants in RARS1 impair ArgRS activity and do not only lead to a classic hypomyelination presentation with nystagmus and spasticity, but to a wide spectrum, ranging from severe, early-onset epileptic encephalopathy with brain atrophy to mild disease with relatively preserved myelination.
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23
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Human diseases linked to cytoplasmic aminoacyl-tRNA synthetases. BIOLOGY OF AMINOACYL-TRNA SYNTHETASES 2020; 48:277-319. [DOI: 10.1016/bs.enz.2020.06.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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24
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Schaffer AE, Pinkard O, Coller JM. tRNA Metabolism and Neurodevelopmental Disorders. Annu Rev Genomics Hum Genet 2019; 20:359-387. [PMID: 31082281 DOI: 10.1146/annurev-genom-083118-015334] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
tRNAs are short noncoding RNAs required for protein translation. The human genome includes more than 600 putative tRNA genes, many of which are considered redundant. tRNA transcripts are subject to tightly controlled, multistep maturation processes that lead to the removal of flanking sequences and the addition of nontemplated nucleotides. Furthermore, tRNAs are highly structured and posttranscriptionally modified. Together, these unique features have impeded the adoption of modern genomics and transcriptomics technologies for tRNA studies. Nevertheless, it has become apparent from human neurogenetic research that many tRNA biogenesis proteins cause brain abnormalities and other neurological disorders when mutated. The cerebral cortex, cerebellum, and peripheral nervous system show defects, impairment, and degeneration upon tRNA misregulation, suggesting that they are particularly sensitive to changes in tRNA expression or function. An integrated approach to identify tRNA species and contextually characterize tRNA function will be imperative to drive future tool development and novel therapeutic design for tRNA-associated disorders.
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Affiliation(s)
- Ashleigh E Schaffer
- Department of Genetics and Genome Sciences and Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio 44106, USA;
| | - Otis Pinkard
- Department of Genetics and Genome Sciences and Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio 44106, USA;
| | - Jeffery M Coller
- Department of Genetics and Genome Sciences and Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio 44106, USA;
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25
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BoAli A, Tlili-Graiess K, AlHashem A, AlShahwan S, Zuccoli G, Tabarki B. Novel Homozygous Mutation of the AIMP1 Gene: A Milder Neuroimaging Phenotype With Preservation of the Deep White Matter. Pediatr Neurol 2019; 91:57-61. [PMID: 30477741 DOI: 10.1016/j.pediatrneurol.2018.09.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/05/2018] [Accepted: 09/22/2018] [Indexed: 01/18/2023]
Abstract
BACKGROUND Mutations in AIMP1, which plays an important role in the development and maintenance of axon-cytoskeleton integrity and regulating neurofilaments, cause neurodegeneration of variable severity and white matter abnormalities. METHODS From the patient records we analyzed the clinical evaluation, molecular genetics, neurodiagnostic, and neuroradiological investigations. RESULTS We describe six members of a large consanguineous family with a phenotype of severe neurodegeneration in the form of developmental delays, progressive microcephaly, epilepsy, and failure to thrive. MRI showed callosal atrophy and T2 hyperintensity in the superficial white matter. The periventricular and deep white matter structures were, however, preserved. MR spectroscopy demonstrated N-acetylaspartate preservation without evidence of neuroinflammation. Exome sequencing showed a novel homozygous mutation of the AIMP1 gene in all individuals: c.917A>G (p.(Asp306Gly)). CONCLUSIONS This novel homozygous mutation of the AIMP1 gene is characterized by preserved development of the periventricular and deep white matter structures as demonstrated by MRI and MR spectroscopy correlation.
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Affiliation(s)
- Ahmed BoAli
- Division of Pediatric Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Kalthoum Tlili-Graiess
- Division of Neuroradiology, Department of Radiology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Amal AlHashem
- Division of Genetics, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Saad AlShahwan
- Division of Pediatric Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Giulio Zuccoli
- Division of Neuroradiology, Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Brahim Tabarki
- Division of Pediatric Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.
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Accogli A, Guerrero K, D'Agostino MD, Tran L, Cieuta-Walti C, Thiffault I, Chénier S, Schwartzentruber J, Majewski J, Bernard G. Biallelic Loss-of-Function Variants in AIMP1 Cause a Rare Neurodegenerative Disease. J Child Neurol 2019; 34:74-80. [PMID: 30486714 DOI: 10.1177/0883073818811223] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
AIMP1/p43, is a noncatalytic component of the mammalian multi-tRNA synthetase complex that catalyzes the ligation of amino acids to their cognate tRNAs. AIMP1 is largely expressed in the central nervous system, where it is part of the regulatory machine of the neurofilament assembly, playing a crucial role in neuronal development and function. To date, nonsense mutations in AIMP1 have been associated with a primary neurodegenerative disorder consisting of cerebral atrophy, hypomyelination, microcephaly and epilepsy, whereas missense mutations have recently been linked to intellectual disability without neurodegeneration. Here, we report the first French-Canadian patient with a novel frameshift AIMP1 homozygous mutation (c.191_192delAA, p.Gln64Argfs*25), resulting in a severe neurodegenerative phenotype. We review and discuss the phenotypic spectrum associated with AIMP1 pathogenic variants.
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Affiliation(s)
- Andrea Accogli
- 1 Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, Canada.,2 UOC Neurochirurgia, Istituto Giannina Gaslini, Genova, Italy.,3 Università degli Studi di Genova, Genoa, Italy
| | - Kether Guerrero
- 1 Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, Canada.,4 Department of Internal Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Canada.,5 Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, Canada
| | - Maria Daniela D'Agostino
- 4 Department of Internal Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Canada.,6 Department of Human Genetics, McGill University, Montreal, Canada
| | - Luan Tran
- 1 Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, Canada.,4 Department of Internal Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Canada.,5 Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, Canada
| | - Cécile Cieuta-Walti
- 7 Service de Neuropédiatre, Université de Sherbrooke, Quebec, Canada.,8 Institut Lejeune, Paris, France
| | - Isabelle Thiffault
- 9 Center for Pediatric Genomic Medicine, Children's Mercy Hospital, Kansas City, MO, USA.,10 University of Missouri-Kansas City School of Medicine, Kansas City, MO, USA
| | - Sébastien Chénier
- 11 Department of Pediatrics, Division of Medical Genetics, Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada
| | | | - Jacek Majewski
- 6 Department of Human Genetics, McGill University, Montreal, Canada
| | | | - Geneviève Bernard
- 1 Departments of Neurology and Neurosurgery, Pediatrics and Human Genetics, McGill University, Montreal, Canada.,4 Department of Internal Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Canada.,5 Child Health and Human Development Program, Research Institute of the McGill University Health Center, Montreal, Canada
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27
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Mendes MI, Gutierrez Salazar M, Guerrero K, Thiffault I, Salomons GS, Gauquelin L, Tran LT, Forget D, Gauthier MS, Waisfisz Q, Smith DE, Simons C, van der Knaap MS, Marquardt I, Lemes A, Mierzewska H, Weschke B, Koehler W, Coulombe B, Wolf NI, Bernard G. Bi-allelic Mutations in EPRS, Encoding the Glutamyl-Prolyl-Aminoacyl-tRNA Synthetase, Cause a Hypomyelinating Leukodystrophy. Am J Hum Genet 2018; 102:676-684. [PMID: 29576217 DOI: 10.1016/j.ajhg.2018.02.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 02/13/2018] [Indexed: 12/21/2022] Open
Abstract
Hypomyelinating leukodystrophies are genetic disorders characterized by insufficient myelin deposition during development. They are diagnosed on the basis of both clinical and MRI features followed by genetic confirmation. Here, we report on four unrelated affected individuals with hypomyelination and bi-allelic pathogenic variants in EPRS, the gene encoding cytoplasmic glutamyl-prolyl-aminoacyl-tRNA synthetase. EPRS is a bifunctional aminoacyl-tRNA synthetase that catalyzes the aminoacylation of glutamic acid and proline tRNA species. It is a subunit of a large multisynthetase complex composed of eight aminoacyl-tRNA synthetases and its three interacting proteins. In total, five different EPRS mutations were identified. The p.Pro1115Arg variation did not affect the assembly of the multisynthetase complex (MSC) as monitored by affinity purification-mass spectrometry. However, immunoblot analyses on protein extracts from fibroblasts of the two affected individuals sharing the p.Pro1115Arg variant showed reduced EPRS amounts. EPRS activity was reduced in one affected individual's lymphoblasts and in a purified recombinant protein model. Interestingly, two other cytoplasmic aminoacyl-tRNA synthetases have previously been implicated in hypomyelinating leukodystrophies bearing clinical and radiological similarities to those in the individuals we studied. We therefore hypothesized that leukodystrophies caused by mutations in genes encoding cytoplasmic aminoacyl-tRNA synthetases share a common underlying mechanism, such as reduced protein availability, abnormal assembly of the multisynthetase complex, and/or abnormal aminoacylation, all resulting in reduced translation capacity and insufficient myelin deposition in the developing brain.
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