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Kuo ME, Parish M, Jonatzke KE, Antonellis A. Comprehensive assessment of recessive, pathogenic AARS1 alleles in a humanized yeast model reveals loss-of-function and dominant-negative effects. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.20.599900. [PMID: 38979321 PMCID: PMC11230197 DOI: 10.1101/2024.06.20.599900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Alanyl-tRNA synthetase 1 (AARS1) encodes the enzyme that ligates tRNA molecules to alanine in the cytoplasm, which is required for protein translation. Variants in AARS1 have been implicated in early-onset, multi-system recessive phenotypes and in later-onset dominant peripheral neuropathy; to date, no single variant has been associated with both dominant and recessive diseases raising questions about shared mechanisms between the two inheritance patterns. AARS1 variants associated with recessive disease are predicted to result in null or hypomorphic alleles and this has been demonstrated, in part, via yeast complementation assays. However, pathogenic alleles have not been assessed in a side-by-side manner to carefully scrutinize the strengths and limitations of this model system. To address this, we employed a humanized yeast model to evaluate the functional consequences of all AARS1 missense variants reported in recessive disease. The majority of variants showed variable loss-of-function effects, ranging from no growth to significantly reduced growth. These data deem yeast a reliable model to test the functional consequences of human AARS1 variants; however, our data indicate that this model is prone to false-negative results and is not informative for genotype-phenotype studies. We next tested missense variants associated with no growth for dominant-negative effects. Interestingly, K81T AARS1, a variant implicated in recessive disease, demonstrated loss-of-function and dominant-negative effects, indicating that certain AARS1 variants may be capable of causing both dominant and recessive disease phenotypes.
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Affiliation(s)
- Molly E Kuo
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
- Medical Scientist Training Program, University of Michigan, Ann Arbor, Michigan, USA
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan, USA
| | - Maclaine Parish
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Kira E Jonatzke
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Anthony Antonellis
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan, USA
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
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Meyer-Schuman R, Marte S, Smith TJ, Feely SME, Kennerson M, Nicholson G, Shy ME, Koutmou KS, Antonellis A. A humanized yeast model reveals dominant-negative properties of neuropathy-associated alanyl-tRNA synthetase mutations. Hum Mol Genet 2023; 32:2177-2191. [PMID: 37010095 PMCID: PMC10281750 DOI: 10.1093/hmg/ddad054] [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: 01/04/2023] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 04/04/2023] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) are essential enzymes that ligate tRNA molecules to cognate amino acids. Heterozygosity for missense variants or small in-frame deletions in six ARS genes causes dominant axonal peripheral neuropathy. These pathogenic variants reduce enzyme activity without significantly decreasing protein levels and reside in genes encoding homo-dimeric enzymes. These observations raise the possibility that neuropathy-associated ARS variants exert a dominant-negative effect, reducing overall ARS activity below a threshold required for peripheral nerve function. To test such variants for dominant-negative properties, we developed a humanized yeast assay to co-express pathogenic human alanyl-tRNA synthetase (AARS1) mutations with wild-type human AARS1. We show that multiple loss-of-function AARS1 mutations impair yeast growth through an interaction with wild-type AARS1, but that reducing this interaction rescues yeast growth. This suggests that neuropathy-associated AARS1 variants exert a dominant-negative effect, which supports a common, loss-of-function mechanism for ARS-mediated dominant peripheral neuropathy.
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Affiliation(s)
- Rebecca Meyer-Schuman
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Sheila Marte
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Tyler J Smith
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Shawna M E Feely
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Marina Kennerson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW 2139, Australia
- Sydney Medical School, University of Sydney, Sydney, NSW 2050, Australia
- Molecular Medicine Laboratory, Concord General Repatriation Hospital, Sydney, NSW 2139, Australia
| | - Garth Nicholson
- Northcott Neuroscience Laboratory, ANZAC Research Institute, Sydney, NSW 2139, Australia
- Sydney Medical School, University of Sydney, Sydney, NSW 2050, Australia
- Molecular Medicine Laboratory, Concord General Repatriation Hospital, Sydney, NSW 2139, Australia
| | - Mike E Shy
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Kristin S Koutmou
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Anthony Antonellis
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Kalotay E, Klugmann M, Housley GD, Fröhlich D. Dominant aminoacyl-tRNA synthetase disorders: lessons learned from in vivo disease models. Front Neurosci 2023; 17:1182845. [PMID: 37274211 PMCID: PMC10234151 DOI: 10.3389/fnins.2023.1182845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 04/05/2023] [Indexed: 06/06/2023] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) play an essential role in protein synthesis, being responsible for ligating tRNA molecules to their corresponding amino acids in a reaction known as 'tRNA aminoacylation'. Separate ARSs carry out the aminoacylation reaction in the cytosol and in mitochondria, and mutations in almost all ARS genes cause pathophysiology most evident in the nervous system. Dominant mutations in multiple cytosolic ARSs have been linked to forms of peripheral neuropathy including Charcot-Marie-Tooth disease, distal hereditary motor neuropathy, and spinal muscular atrophy. This review provides an overview of approaches that have been employed to model each of these diseases in vivo, followed by a discussion of the existing animal models of dominant ARS disorders and key mechanistic insights that they have provided. In summary, ARS disease models have demonstrated that loss of canonical ARS function alone cannot fully account for the observed disease phenotypes, and that pathogenic ARS variants cause developmental defects within the peripheral nervous system, despite a typically later onset of disease in humans. In addition, aberrant interactions between mutant ARSs and other proteins have been shown to contribute to the disease phenotypes. These findings provide a strong foundation for future research into this group of diseases, providing methodological guidance for studies on ARS disorders that currently lack in vivo models, as well as identifying candidate therapeutic targets.
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Affiliation(s)
- Elizabeth Kalotay
- Translational Neuroscience Facility and Department of Physiology, School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Matthias Klugmann
- Translational Neuroscience Facility and Department of Physiology, School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Gary D. Housley
- Translational Neuroscience Facility and Department of Physiology, School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Dominik Fröhlich
- Translational Neuroscience Facility and Department of Physiology, School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
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Setlere S, Jurcenko M, Gailite L, Rots D, Kenina V. Alanyl-tRNA Synthetase 1 Gene Variants in Hereditary Neuropathy. Neurol Genet 2022; 8:e200019. [PMID: 36092982 PMCID: PMC9450682 DOI: 10.1212/nxg.0000000000200019] [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: 12/22/2022] [Accepted: 07/01/2022] [Indexed: 11/15/2022]
Abstract
Background and ObjectivesOur objective was to report 2 novel variants and to reclassify previously reported alanyl-tRNA synthetase 1 (AARS1) variants associated with hereditary neuropathy and to summarize the clinical features of a previously published cohort of patients.MethodsWe performed detailed neurologic and electrophysiologic assessments and segregation analysis of 2 unrelated families with Charcot-Marie-Tooth (CMT) disease with novel variants in the AARS1 gene. Via literature search, we found studies that included neuropathy cases with AARS1 variants; we then reviewed and reclassified these variants.ResultsWe identified 2 CMT families harboring previously unreported likely pathogenic AARS1 variants: c.1823C>A p.(Thr608Lys) and c.1815C>G p.(His605Gln). In addition, we reinterpreted a total of 35 different AARS1 variants reported in cases with neuropathy from the literature: 9 variants fulfilled the current criteria for being (likely) pathogenic. We compiled and summarized standardized clinical and genotypic information for 90 affected individuals from 32 families with (likely) pathogenic AARS1 variants. Most experienced motor weakness and sensory loss in the lower limbs.DiscussionIn total, 11 AARS1 variants can currently be classified as pathogenic or likely pathogenic and are associated with sensorimotor axonal or intermediate, slowly progressive polyneuropathy with common asymmetry and variable age of symptom onset with no apparent involvement of other organ systems.
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Jin B, Xie L, Zhan D, Zhou L, Feng Z, He J, Qin J, Zhao C, Luo L, Li L. Nrf2 dictates the neuronal survival and differentiation of embryonic zebrafish harboring compromised alanyl-tRNA synthetase. Development 2022; 149:276217. [DOI: 10.1242/dev.200342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 07/28/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
tRNA synthetase deficiency leads to unfolded protein responses in neuronal disorders; however, its function in embryonic neurogenesis remains unclear. This study identified an aars1cq71/cq71 mutant zebrafish allele that showed increased neuronal apoptosis and compromised neurogenesis. aars1 transcripts were highly expressed in primary neural progenitor cells, and their aberration resulted in protein overloading and activated Perk. nfe2l2b, a paralog of mammalian Nfe2l2, which encodes Nrf2, is a pivotal executor of Perk signaling that regulates neuronal phenotypes in aars1cq71/cq71 mutants. Interference of nfe2l2b in nfe2l2bΔ1/Δ1 mutants did not affect global larval development. However, aars1cq71/cq71;nfe2l2bΔ1/Δ1 mutant embryos exhibited increased neuronal cell survival and neurogenesis compared with their aars1cq71/cq71 siblings. nfe2l2b was harnessed by Perk at two levels. Its transcript was regulated by Chop, an implementer of Perk. It was also phosphorylated by Perk. Both pathways synergistically assured the nuclear functions of nfe2l2b to control cell survival by targeting p53. Our study extends the understanding of tRNA synthetase in neurogenesis and implies that Nrf2 is a cue to mitigate neurodegenerative pathogenesis.
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Affiliation(s)
- Binbin Jin
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University 1 , Chongqing 400715 , China
| | - Liqin Xie
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University 1 , Chongqing 400715 , China
| | - Dan Zhan
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University 1 , Chongqing 400715 , China
| | - Luping Zhou
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University 1 , Chongqing 400715 , China
| | - Zhi Feng
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University 1 , Chongqing 400715 , China
| | - Jiangyong He
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University 1 , Chongqing 400715 , China
| | - Jie Qin
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University 1 , Chongqing 400715 , China
| | - Congjian Zhao
- Chongqing Engineering Research Center of Medical Electronics and Information Technology, School of Biomedical Engineering and informatics, Chongqing University of Posts and Telecommunications 2 , Chongqing 40065 , China
| | - Lingfei Luo
- Institute of Developmental Biology and Regenerative Medicine, Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, Southwest University 1 , Chongqing 400715 , China
| | - Li Li
- Research Center of Stem Cells and Ageing, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences 3 , Chongqing 400714 , China
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Høyer H, Busk ØL, Esbensen QY, Røsby O, Hilmarsen HT, Russell MB, Nyman TA, Braathen GJ, Nilsen HL. Clinical characteristics and proteome modifications in two Charcot-Marie-Tooth families with the AARS1 Arg326Trp mutation. BMC Neurol 2022; 22:299. [PMID: 35971119 PMCID: PMC9377087 DOI: 10.1186/s12883-022-02828-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 08/03/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aminoacyl tRNA-synthetases are ubiquitously-expressed enzymes that attach amino acids to their cognate tRNA molecules. Mutations in several genes encoding aminoacyl tRNA-synthetases, have been associated with peripheral neuropathy, i.e. AARS1, GARS1, HARS1, YARS1 and WARS1. The pathogenic mechanism underlying AARS1-related neuropathy is not known. METHODS From 2012 onward, all probands presenting at Telemark Hospital (Skien, Norway) with peripheral neuropathy were screened for variants in AARS1 using an "in-house" next-generation sequencing panel. DNA from patient's family members was examined by Sanger sequencing. Blood from affected family members and healthy controls were used for quantification of AARS1 mRNA and alanine. Proteomic analyses were conducted in peripheral blood mononuclear cells (PBMC) from four affected family members and five healthy controls. RESULTS Seventeen individuals in two Norwegian families affected by Charcot-Marie-Tooth disease (CMT) were characterized in this study. The heterozygous NM_001605.2:c.976C > T p.(Arg326Trp) AARS1 mutation was identified in ten affected family members. All living carriers had a mild to severe length-dependent sensorimotor neuropathy. Three deceased obligate carriers aged 74-98 were reported to be unaffected, but were not examined in the clinic. Proteomic studies in PBMC from four affected individuals suggest an effect on the immune system mediated by components of a systemic response to chronic injury and inflammation. Furthermore, altered expression of proteins linked to mitochondrial function/dysfunction was observed. Proteomic data are available via ProteomeXchange using identifier PXD023842. CONCLUSION This study describes clinical and neurophysiological features linked to the p.(Arg326Trp) variant of AARS1 in CMT-affected members of two Norwegian families. Proteomic analyses based on of PBMC from four CMT-affected individuals suggest that involvement of inflammation and mitochondrial dysfunction might contribute to AARS1 variant-associated peripheral neuropathy.
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Affiliation(s)
- Helle Høyer
- Department of Medical Genetics, Telemark Hospital, PB 2900 Kjørbekk, 3710, Skien, Norway.
| | - Øyvind L Busk
- Department of Medical Genetics, Telemark Hospital, PB 2900 Kjørbekk, 3710, Skien, Norway
| | - Q Ying Esbensen
- Department of Clinical Molecular Biology, University of Oslo and Akershus University Hospital, 1478, Lørenskog, Norway
| | - Oddveig Røsby
- Department of Medical Genetics, Telemark Hospital, PB 2900 Kjørbekk, 3710, Skien, Norway.,Department of Medical Genetics, Oslo University Hospital, 0424, Oslo, Norway
| | - Hilde T Hilmarsen
- Department of Medical Genetics, Telemark Hospital, PB 2900 Kjørbekk, 3710, Skien, Norway
| | - Michael B Russell
- Head and Neck Research Group, Division for Research and Innovation, Akershus University Hospital, 1478, Lørenskog, Norway.,Institute of Clinical Medicine, Campus Akershus University Hospital, University of Oslo, 1474, Norbyhagen, Norway
| | - Tuula A Nyman
- Department of Immunology, Institute of Clinical Medicine, University of Oslo and Rikshospitalet, 0372, Oslo, Norway
| | - Geir J Braathen
- Department of Medical Genetics, Telemark Hospital, PB 2900 Kjørbekk, 3710, Skien, Norway
| | - Hilde L Nilsen
- Department of Clinical Molecular Biology, University of Oslo and Akershus University Hospital, 1478, Lørenskog, Norway
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刘 梅, 方 朴, 王 严, 丛 璐, 范 洋, 袁 远, 徐 燕, 张 俊, 洪 道. [Clinical, pathological and genetic characteristics of 8 patients with distal hereditary motor neuropathy]. BEIJING DA XUE XUE BAO. YI XUE BAN = JOURNAL OF PEKING UNIVERSITY. HEALTH SCIENCES 2021; 53:957-963. [PMID: 34650302 PMCID: PMC8517674 DOI: 10.19723/j.issn.1671-167x.2021.05.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Indexed: 06/13/2023]
Abstract
OBJECTIVE Distal hereditary motor neuropathy (dHMN) comprises a heterogeneous group of inherited disorders associated with neurodegeneration of motor nerves and neurons, mainly charac-terized by progressive atrophy and weakness of distal muscle without clinical or electrophysiological sensory abnormalities. To improve the recognition and diagnosis of the disease, we summarized the clinical manifestations, electrophysiological, pathological, and genetic characteristics in eight patients with dHMN. METHODS Eight probands from different families diagnosed with dHMN were recruited in this study between June 2018 and April 2019 at Peking University People's Hospital. Eight patients underwent complete neurological examination and standard electrophysiological examinations. The clinical criteria were consistent with the patients presenting with a pure motor neuropathy with no sensory changes on electrophysiology. The detailed clinical symptoms, neurophysiological examinations, pathological features and gene mutations were analyzed retrospectively. Genetic testing was performed on the eight patients using targeted next-generation sequencing panel for inherited neuromuscular disorder and was combined with segregation analysis. RESULTS The age of onset ranged between 11 and 64 years (median 39.5 years) in our dHMN patients. All the cases showed a slowly progressive disease course, mainly characterized by distal limb muscle weakness and atrophy. The motor nerve conduction revealed decreased compound muscle action potential amplitude and velocity, while the sensory nerve conduction velocities and action potentials were not affected. Needle electromyography indicated neurogenic chronic denervation in all patients. Muscle biopsy performed in two patients demonstrated neurogenic skeletal muscle damage. Sural nerve biopsy was performed in one patient, Semithin sections shows relatively normal density and structure of large myelinated fibers, except very few fibers with thin myelin sheaths, which suggested very mild sensory nerve involvement. Eight different genes known to be associated with dHMN were identified in the patients by next-generation sequencing, pathogenic dHMN mutations were identified in three genes, and the detection rate of confirmed genetic diagnosis of dHMN was 37.5% (3/8). Whereas five variants of uncertain significance (VUS) were identified, among which two novel variants co-segregated the phenotype. CONCLUSION dHMN is a group of inherited peripheral neuropathies with great clinical and genetic heterogeneity. Next-generation sequencing is widely used to discover pathogenic genes in patients with dHMN, but more than half of the patients still remain genetically unknown.
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Affiliation(s)
- 梅歌 刘
- 北京大学人民医院神经内科,北京 100044Department of Neurology, Peking University People's Hospital, Beijing 100044, China
| | - 朴 方
- 南昌大学第一附属医院神经内科,南昌 330006Department of Neurology, the First Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - 严 王
- 北京大学人民医院神经内科,北京 100044Department of Neurology, Peking University People's Hospital, Beijing 100044, China
| | - 璐 丛
- 北京大学人民医院神经内科,北京 100044Department of Neurology, Peking University People's Hospital, Beijing 100044, China
| | - 洋溢 范
- 北京大学人民医院神经内科,北京 100044Department of Neurology, Peking University People's Hospital, Beijing 100044, China
| | - 远 袁
- 北京大学人民医院神经内科,北京 100044Department of Neurology, Peking University People's Hospital, Beijing 100044, China
| | - 燕 徐
- 北京大学人民医院神经内科,北京 100044Department of Neurology, Peking University People's Hospital, Beijing 100044, China
| | - 俊 张
- 北京大学人民医院神经内科,北京 100044Department of Neurology, Peking University People's Hospital, Beijing 100044, China
| | - 道俊 洪
- 北京大学人民医院神经内科,北京 100044Department of Neurology, Peking University People's Hospital, Beijing 100044, China
- 南昌大学第一附属医院神经内科,南昌 330006Department of Neurology, the First Affiliated Hospital of Nanchang University, Nanchang 330006, China
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Drosophila Models for Charcot-Marie-Tooth Neuropathy Related to Aminoacyl-tRNA Synthetases. Genes (Basel) 2021; 12:genes12101519. [PMID: 34680913 PMCID: PMC8536177 DOI: 10.3390/genes12101519] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/20/2021] [Accepted: 09/24/2021] [Indexed: 11/29/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRS) represent the largest cluster of proteins implicated in Charcot–Marie–Tooth neuropathy (CMT), the most common neuromuscular disorder. Dominant mutations in six aaRS cause different axonal CMT subtypes with common clinical characteristics, including progressive distal muscle weakness and wasting, impaired sensory modalities, gait problems and skeletal deformities. These clinical manifestations are caused by “dying back” axonal degeneration of the longest peripheral sensory and motor neurons. Surprisingly, loss of aminoacylation activity is not a prerequisite for CMT to occur, suggesting a gain-of-function disease mechanism. Here, we present the Drosophila melanogaster disease models that have been developed to understand the molecular pathway(s) underlying GARS1- and YARS1-associated CMT etiology. Expression of dominant CMT mutations in these aaRSs induced comparable neurodegenerative phenotypes, both in larvae and adult animals. Interestingly, recent data suggests that shared molecular pathways, such as dysregulation of global protein synthesis, might play a role in disease pathology. In addition, it has been demonstrated that the important function of nuclear YARS1 in transcriptional regulation and the binding properties of mutant GARS1 are also conserved and can be studied in D. melanogaster in the context of CMT. Taken together, the fly has emerged as a faithful companion model for cellular and molecular studies of aaRS-CMT that also enables in vivo investigation of candidate CMT drugs.
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Zuko A, Mallik M, Thompson R, Spaulding EL, Wienand AR, Been M, Tadenev ALD, van Bakel N, Sijlmans C, Santos LA, Bussmann J, Catinozzi M, Das S, Kulshrestha D, Burgess RW, Ignatova Z, Storkebaum E. tRNA overexpression rescues peripheral neuropathy caused by mutations in tRNA synthetase. Science 2021; 373:1161-1166. [PMID: 34516840 DOI: 10.1126/science.abb3356] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Amila Zuko
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Moushami Mallik
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands.,Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Robin Thompson
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Hamburg, Germany
| | - Emily L Spaulding
- The Jackson Laboratory, Bar Harbor, ME, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
| | - Anne R Wienand
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Marije Been
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands
| | | | - Nick van Bakel
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Céline Sijlmans
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Leonardo A Santos
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Hamburg, Germany
| | - Julia Bussmann
- Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Marica Catinozzi
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands.,Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Sarada Das
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Hamburg, Germany
| | - Divita Kulshrestha
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands.,Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Robert W Burgess
- The Jackson Laboratory, Bar Harbor, ME, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA
| | - Zoya Ignatova
- Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Hamburg, Germany
| | - Erik Storkebaum
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, Nijmegen, Netherlands.,Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany
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10
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Vinogradova ES, Nikonov OS, Nikonova EY. Associations between Neurological Diseases and Mutations in the Human Glycyl-tRNA Synthetase. BIOCHEMISTRY (MOSCOW) 2021; 86:S12-S23. [PMID: 33827397 PMCID: PMC7905983 DOI: 10.1134/s0006297921140029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Aminoacyl-RNA synthetases (aaRSs) are among the key enzymes of protein biosynthesis. They are responsible for conducting the first step in the protein biosynthesis, namely attaching amino acids to the corresponding tRNA molecules both in cytoplasm and mitochondria. More and more research demonstrates that mutations in the genes encoding aaRSs lead to the development of various neurodegenerative diseases, such as incurable Charcot–Marie–Tooth disease (CMT) and distal spinal muscular atrophy. Some mutations result in the loss of tRNA aminoacylation activity, while other mutants retain their classical enzyme activity. In the latter case, disease manifestations are associated with additional neuron-specific functions of aaRSs. At present, seven aaRSs (GlyRS, TyrRS, AlaRS, HisRS, TrpRS, MetRS, and LysRS) are known to be involved in the CMT etiology with glycyl-tRNA synthetase (GlyRS) being the most studied of them.
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Affiliation(s)
| | - Oleg S Nikonov
- Institute of Protein Research, Pushchino, Moscow Region, 142290, Russia
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Abstract
Charcot-Marie-Tooth disease (CMT) is a devastating motor and sensory neuropathy with an estimated 100,000 afflicted individuals in the US. Unexpectedly, aminoacyl-tRNA synthetases are the largest disease-associated protein family. A natural explanation is that the disease is associated with weak translation or mistranslation (caused by editing defects). However, our results with six different disease-causing mutants in AlaRS ruled out defects in aminoacylation or editing as causal factors. Instead, specific mutant proteins gained a neuropilin 1 (Nrp1)-AlaRS interaction. Previously a gain of Nrp1 interaction with a different disease-causing tRNA synthetase was mechanistically linked to the pathology of CMT. Thus, our results raise the possibility that pathological engagement of Nrp1 is common to at least a subset of tRNA synthetase-associated cases of CMT. Through dominant mutations, aminoacyl-tRNA synthetases constitute the largest protein family linked to Charcot-Marie-Tooth disease (CMT). An example is CMT subtype 2N (CMT2N), caused by individual mutations spread out in AlaRS, including three in the aminoacylation domain, thereby suggesting a role for a tRNA-charging defect. However, here we found that two are aminoacylation defective but that the most widely distributed R329H is normal as a purified protein in vitro and in unfractionated patient cell samples. Remarkably, in contrast to wild-type (WT) AlaRS, all three mutant proteins gained the ability to interact with neuropilin 1 (Nrp1), the receptor previously linked to CMT pathogenesis in GlyRS. The aberrant AlaRS-Nrp1 interaction is further confirmed in patient samples carrying the R329H mutation. However, CMT2N mutations outside the aminoacylation domain do not induce the Nrp1 interaction. Detailed biochemical and biophysical investigations, including X-ray crystallography, small-angle X-ray scattering, hydrogen-deuterium exchange (HDX), switchSENSE hydrodynamic diameter determinations, and protease digestions reveal a mutation-induced structural loosening of the aminoacylation domain that correlates with the Nrp1 interaction. The b1b2 domains of Nrp1 are responsible for the interaction with R329H AlaRS. The results suggest Nrp1 is more broadly associated with CMT-associated members of the tRNA synthetase family. Moreover, we revealed a distinct structural loosening effect induced by a mutation in the editing domain and a lack of conformational impact with C-Ala domain mutations, indicating mutations in the same protein may cause neuropathy through different mechanisms. Our results show that, as with other CMT-associated tRNA synthetases, aminoacylation per se is not relevant to the pathology.
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12
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Beijer D, Baets J. The expanding genetic landscape of hereditary motor neuropathies. Brain 2021; 143:3540-3563. [PMID: 33210134 DOI: 10.1093/brain/awaa311] [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] [Received: 05/29/2020] [Revised: 07/15/2020] [Accepted: 07/27/2020] [Indexed: 12/12/2022] Open
Abstract
Hereditary motor neuropathies are clinically and genetically diverse disorders characterized by length-dependent axonal degeneration of lower motor neurons. Although currently as many as 26 causal genes are known, there is considerable missing heritability compared to other inherited neuropathies such as Charcot-Marie-Tooth disease. Intriguingly, this genetic landscape spans a discrete number of key biological processes within the peripheral nerve. Also, in terms of underlying pathophysiology, hereditary motor neuropathies show striking overlap with several other neuromuscular and neurological disorders. In this review, we provide a current overview of the genetic spectrum of hereditary motor neuropathies highlighting recent reports of novel genes and mutations or recent discoveries in the underlying disease mechanisms. In addition, we link hereditary motor neuropathies with various related disorders by addressing the main affected pathways of disease divided into five major processes: axonal transport, tRNA aminoacylation, RNA metabolism and DNA integrity, ion channels and transporters and endoplasmic reticulum.
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Affiliation(s)
- Danique Beijer
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium
| | - Jonathan Baets
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Belgium
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13
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Zhang H, Zhou ZW, Sun L. Aminoacyl-tRNA synthetases in Charcot-Marie-Tooth disease: A gain or a loss? J Neurochem 2020; 157:351-369. [PMID: 33236345 PMCID: PMC8247414 DOI: 10.1111/jnc.15249] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/17/2020] [Accepted: 11/19/2020] [Indexed: 01/05/2023]
Abstract
Charcot‐Marie‐Tooth disease (CMT) is one of the most common inherited neurodegenerative disorders with an increasing number of CMT‐associated variants identified as causative factors, however, there has been no effective therapy for CMT to date. Aminoacyl‐tRNA synthetases (aaRS) are essential enzymes in translation by charging amino acids onto their cognate tRNAs during protein synthesis. Dominant monoallelic variants of aaRSs have been largely implicated in CMT. Some aaRSs variants affect enzymatic activity, demonstrating a loss‐of‐function property. In contrast, loss of aminoacylation activity is neither necessary nor sufficient for some aaRSs variants to cause CMT. Instead, accumulating evidence from CMT patient samples, animal genetic studies or protein conformational analysis has pinpointed toxic gain‐of‐function of aaRSs variants in CMT, suggesting complicated mechanisms underlying the pathogenesis of CMT. In this review, we summarize the latest advances in studies on CMT‐linked aaRSs, with a particular focus on their functions. The current challenges, future direction and the promising candidates for potential treatment of CMT are also discussed. ![]()
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Affiliation(s)
- Han Zhang
- Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, China
| | - Zhong-Wei Zhou
- School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Litao Sun
- School of Public Health (Shenzhen), Sun Yat-sen University, Guangzhou, China
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14
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Abstract
Among the 20 cytoplasmic aminoacyl-tRNA synthetases (aaRSs), alanyl-tRNA synthetase (AlaRS) has unique features. AlaRS is the only aaRS that exclusively recognizes a single G3:U70 wobble base pair in the acceptor stem of tRNA, which serves as the identity element for both the synthetic and the proofreading activities of the synthetase. The recognition is relaxed during evolution and eukaryotic AlaRS can mis-aminoacylate noncognate tRNAs with a G4:U69 base pair seemingly as a deliberate gain of function for unknown reasons. Unlike other class II aaRSs, dimerization of AlaRS is not necessarily required for aminoacylation possibly due to functional compensations from the C-terminal domain (C-Ala). In contrast to other 19 cytoplasmic aaRSs that append additional domains or motifs to acquire new functions during evolution, the functional expansion of AlaRS is likely achieved through transformations of the existing C-Ala. Given both essential canonical and diverse non-canonical roles of AlaRS, dysfunction of AlaRS leads to neurodegenerative disorders in human and various pathological phenotypes in mouse models. In this review, the uniqueness of AlaRS in both physiological and pathological events is systematically discussed, with a particular focus on its novel functions gained in evolution.
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Affiliation(s)
- Han Zhang
- Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, Yunnan, China
| | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Litao Sun
- School of Public Health (Shenzhen), Sun Yat-sen University, Guangdong, China
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15
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Kuo ME, Antonellis A, Shakkottai VG. Alanyl-tRNA Synthetase 2 (AARS2)-Related Ataxia Without Leukoencephalopathy. THE CEREBELLUM 2020; 19:154-160. [PMID: 31705293 DOI: 10.1007/s12311-019-01080-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Mutations in the mitochondrial alanyl-tRNA synthetase gene, AARS2, have been reported to cause leukoencephalopathy associated with early ovarian failure, a clinical presentation described as "ovarioleukodystrophy." We present a sibling pair: one with cerebellar ataxia and one with vision loss and cognitive impairment in addition to ataxia. Neither shows evidence of leukoencephalopathy on MRI imaging. Exome sequencing revealed that both siblings are compound heterozygous for AARS2 variants (p.Phe131del and p.Ile328Met). Yeast complementation assays indicate that p.Phe131del AARS2 dramatically impairs gene function and that p.Ile328Met AARS2 is a hypomorphic allele. This work expands the phenotypic spectrum of AARS2-associated disease to include ataxia without leukoencephalopathy.
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Affiliation(s)
- Molly E Kuo
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA.,Medical Scientist Training Program, University of Michigan, Ann Arbor, MI, USA
| | - Anthony Antonellis
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, USA. .,Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA. .,Department of Neurology, University of Michigan, Ann Arbor, MI, USA. .,Medical Science II, 3710A, 1241 E. Catherine St. SPC 5618, Ann Arbor, MI, 48109, USA.
| | - Vikram G Shakkottai
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA. .,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA. .,BSRB, 4009, 109 Zina Pitcher Place, Ann Arbor, MI, 48109, USA.
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16
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Li J, Chen F, Zhang Q, Meng X, Yao X, Risacher SL, Yan J, Saykin AJ, Liang H, Shen L. Genome-wide Network-assisted Association and Enrichment Study of Amyloid Imaging Phenotype in Alzheimer's Disease. Curr Alzheimer Res 2020; 16:1163-1174. [PMID: 31755389 DOI: 10.2174/1567205016666191121142558] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 11/19/2019] [Accepted: 11/21/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND The etiology of Alzheimer's disease remains poorly understood at the mechanistic level, and genome-wide network-based genetics have the potential to provide new insights into the disease mechanisms. OBJECTIVE The study aimed to explore the collective effects of multiple genetic association signals on an AV-45 PET measure, which is a well-known Alzheimer's disease biomarker, by employing a network assisted strategy. METHODS First, we took advantage of a dense module search algorithm to identify modules enriched by genetic association signals in a protein-protein interaction network. Next, we performed statistical evaluation to the modules identified by dense module search, including a normalization process to adjust the topological bias in the network, a replication test to ensure the modules were not found randomly , and a permutation test to evaluate unbiased associations between the modules and amyloid imaging phenotype. Finally, topological analysis, module similarity tests and functional enrichment analysis were performed for the identified modules. RESULTS We identified 24 consensus modules enriched by robust genetic signals in a genome-wide association analysis. The results not only validated several previously reported AD genes (APOE, APP, TOMM40, DDAH1, PARK2, ATP5C1, PVRL2, ELAVL1, ACTN1 and NRF1), but also nominated a few novel genes (ABL1, ABLIM2) that have not been studied in Alzheimer's disease but have shown associations with other neurodegenerative diseases. CONCLUSION The identified genes, consensus modules and enriched pathways may provide important clues to future research on the neurobiology of Alzheimer's disease and suggest potential therapeutic targets.
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Affiliation(s)
- Jin Li
- College of Automation, Harbin Engineering University, Harbin, China
| | - Feng Chen
- College of Automation, Harbin Engineering University, Harbin, China
| | - Qiushi Zhang
- College of Information Engineering, Northeast Dianli University, Jilin, China
| | - Xianglian Meng
- College of Automation, Harbin Engineering University, Harbin, China
| | - Xiaohui Yao
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Shannon L Risacher
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, PA, United States
| | - Jingwen Yan
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, PA, United States
| | - Andrew J Saykin
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, PA, United States
| | - Hong Liang
- College of Automation, Harbin Engineering University, Harbin, China
| | - Li Shen
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
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17
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Alanyl-tRNA synthetase 1 (AARS1) gene mutation in a family with intermediate Charcot-Marie-Tooth neuropathy. Genes Genomics 2020; 42:663-672. [PMID: 32314272 DOI: 10.1007/s13258-020-00933-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 03/31/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND Alanyl-tRNA synthetase 1 (AARS1) gene encodes a ubiquitously expressed class II enzyme that catalyzes the attachment of alanine to the cognate tRNA. AARS1 mutations are frequently responsible for autosomal dominant Charcot-Marie-Tooth disease type 2N (CMT2N). OBJECTIVE To identify pathogenic mutation in the Korean patients with CMT and distal hereditary motor neuronopathy (dHMN). METHODS We screened AARS1 mutations in 373 unrelated CMT families including 318 axonal CMT, 36 dHMN, and 19 intermediate CMT (Int-CMT) who were negative for 17p12 (PMP22) duplication or deletion using whole exome sequencing and targeted sequencing of CMT-related genes. RESULTS This study identified an early onset Int-CMT family harboring an AARS1 p.Arg329His mutation which was previously reported as pathogenic in French and Australian families. The mutation was located in the highly conserved tRNA binding domain and several in silico analyses suggested pathogenic prediction of the mutations. The patients harboring p.Arg329His showed clinically similar phenotypes of the early onset and electrophysiological intermediate type as those in Australian patients with same mutation. We also found a novel c.2564A>G (p.Gln855Arg) in a CMT2 patient, but its' pathogenic role was uncertain (variant of uncertain significance). CONCLUSION This study suggests that the frequency of the AARS1 mutations appears to be quite low in Korean CMT. This is the first report of the AARS1 mutation in Korean CMT patients and will be helpful for the exact molecular diagnosis and treatment of Int-CMT patients.
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18
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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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19
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Martin PB, Hicks AN, Holbrook SE, Cox GA. Overlapping spectrums: The clinicogenetic commonalities between Charcot-Marie-Tooth and other neurodegenerative diseases. Brain Res 2020; 1727:146532. [PMID: 31678418 PMCID: PMC6939129 DOI: 10.1016/j.brainres.2019.146532] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/20/2019] [Accepted: 10/22/2019] [Indexed: 12/11/2022]
Abstract
Charcot-Marie-Tooth (CMT) disease is a progressive and heterogeneous inherited peripheral neuropathy. A myriad of genetic factors have been identified that contribute to the degeneration of motor and sensory axons in a length-dependent manner. Emerging biological themes underlying disease include defects in axonal trafficking, dysfunction in RNA metabolism and protein homeostasis, as well deficits in the cellular stress response. Moreover, genetic contributions to CMT can have overlap with other neuropathies, motor neuron diseases (MNDs) and neurodegenerative disorders. Recent progress in understanding the molecular biology of CMT and overlapping syndromes aids in the search for necessary therapeutic targets.
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Affiliation(s)
- Paige B Martin
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME 04469, USA
| | - Amy N Hicks
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Sarah E Holbrook
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME 04469, USA
| | - Gregory A Cox
- The Jackson Laboratory, Bar Harbor, ME 04609, USA; Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME 04469, USA.
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20
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Sundal C, Carmona S, Yhr M, Almström O, Ljungberg M, Hardy J, Hedberg-Oldfors C, Fred Å, Brás J, Oldfors A, Andersen O, Guerreiro R. An AARS variant as the likely cause of Swedish type hereditary diffuse leukoencephalopathy with spheroids. Acta Neuropathol Commun 2019; 7:188. [PMID: 31775912 PMCID: PMC6880494 DOI: 10.1186/s40478-019-0843-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 11/07/2019] [Indexed: 12/12/2022] Open
Abstract
Swedish type Hereditary Diffuse Leukoencephalopathy with Spheroids (HDLS-S) is a severe adult-onset leukoencephalopathy with the histopathological hallmark of neuraxonal degeneration with spheroids, described in a large family with a dominant inheritance pattern. The initial stage of the disease is dominated by frontal lobe symptoms that develop into a rapidly advancing encephalopathy with pyramidal, deep sensory, extrapyramidal and optic tract symptoms. Median survival is less than 10 years. Recently, pathogenic mutations in CSF1R were reported in a clinically and histologically similar leukoencephalopathy segregating in several families. Still, the cause of HDLS-S remained elusive since its initial description in 1984, with no CSF1R mutations identified in the family. Here we update the original findings associated with HDLS-S after a systematic and recent assessment of several family members. We also report the results from exome sequencing analyses indicating the p.Cys152Phe variant in the alanyl tRNA synthetase (AARS) gene as the probable cause of this disease. The variant affects an amino acid located in the aminoacylation domain of the protein and does not cause differences in splicing or expression in the brain. Brain pathology in one case after 10 years of disease duration showed the end stage of the disease to be characterized by widespread liquefaction of the white matter leaving only some macrophages and glial cells behind the centrifugally progressing front. These results point to AARS as a candidate gene for rapidly progressing adult-onset CSF1R-negative leukoencephalopathies.
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Affiliation(s)
- Christina Sundal
- Department of Clinical Neurology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy, University of Gothenburg, Gröna Stråket 11, 3rd floor, Sahlgrenska University Hospital, 413 45, Göteborg, Sweden
| | - Susana Carmona
- Center for Neurodegenerative Science, Van Andel Institute, 333 Bostwick Ave. N.E, Grand Rapids, MI, 49503-2518, USA
| | - Maria Yhr
- Department of Laboratory Medicine, Institute of Biomedicine, the Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Odd Almström
- Department of Clinical Neurology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy, University of Gothenburg, Gröna Stråket 11, 3rd floor, Sahlgrenska University Hospital, 413 45, Göteborg, Sweden
| | - Maria Ljungberg
- Department of Radiation Physics, Institute of Clinical Sciences, the Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - John Hardy
- Department of Neurodegenerative Disease, Reta Lila Weston Laboratories, Queen Square Genomics, UCL Dementia Research Institute, London, UK
| | - Carola Hedberg-Oldfors
- Department of Laboratory Medicine, Institute of Biomedicine, the Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Åsa Fred
- Department of Pathology, Hospital of Halland, Halmstad, Sweden
| | - José Brás
- Center for Neurodegenerative Science, Van Andel Institute, 333 Bostwick Ave. N.E, Grand Rapids, MI, 49503-2518, USA
- Division of Psychiatry and Behavioral Medicine, Michigan State University College of Human Medicine, Grand Rapids, MI, USA
| | - Anders Oldfors
- Department of Laboratory Medicine, Institute of Biomedicine, the Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Oluf Andersen
- Department of Clinical Neurology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy, University of Gothenburg, Gröna Stråket 11, 3rd floor, Sahlgrenska University Hospital, 413 45, Göteborg, Sweden.
| | - Rita Guerreiro
- Center for Neurodegenerative Science, Van Andel Institute, 333 Bostwick Ave. N.E, Grand Rapids, MI, 49503-2518, USA.
- Division of Psychiatry and Behavioral Medicine, Michigan State University College of Human Medicine, Grand Rapids, MI, USA.
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21
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Weterman MAJ, Kuo M, Kenter SB, Gordillo S, Karjosukarso DW, Takase R, Bronk M, Oprescu S, van Ruissen F, Witteveen RJW, Bienfait HME, Breuning M, Verhamme C, Hou YM, de Visser M, Antonellis A, Baas F. Hypermorphic and hypomorphic AARS alleles in patients with CMT2N expand clinical and molecular heterogeneities. Hum Mol Genet 2019; 27:4036-4050. [PMID: 30124830 DOI: 10.1093/hmg/ddy290] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/04/2018] [Indexed: 01/08/2023] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) are ubiquitously expressed enzymes implicated in several dominant and recessive disease phenotypes. The canonical function of ARSs is to couple an amino acid to a cognate transfer RNA (tRNA). We identified three novel disease-associated missense mutations in the alanyl-tRNA synthetase (AARS) gene in three families with dominant axonal Charcot-Marie-Tooth (CMT) disease. Two mutations (p.Arg326Trp and p.Glu337Lys) are located near a recurrent pathologic change in AARS, p.Arg329His. The third (p.Ser627Leu) is in the editing domain of the protein in which hitherto only mutations associated with recessive encephalopathies have been described. Yeast complementation assays demonstrated that two mutations (p.Ser627Leu and p.Arg326Trp) represent loss-of-function alleles, while the third (p.Glu337Lys) represents a hypermorphic allele. Further, aminoacylation assays confirmed that the third mutation (p.Glu337Lys) increases tRNA charging velocity. To test the effect of each mutation in the context of a vertebrate nervous system, we developed a zebrafish assay. Remarkably, all three mutations caused a pathological phenotype of neural abnormalities when expressed in zebrafish, while expression of the human wild-type messenger RNA (mRNA) did not. Our data indicate that not only functional null or hypomorphic alleles, but also hypermorphic AARS alleles can cause dominantly inherited axonal CMT disease.
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Affiliation(s)
- Marian A J Weterman
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Molly Kuo
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, USA.,Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Susan B Kenter
- Department of Clinical Genetics and Genome Analysis, Academic Medical Center, Amsterdam, Netherlands
| | - Sara Gordillo
- Department of Clinical Genetics and Genome Analysis, Academic Medical Center, Amsterdam, Netherlands
| | - Dyah W Karjosukarso
- Department of Clinical Genetics and Genome Analysis, Academic Medical Center, Amsterdam, Netherlands
| | - Ryuichi Takase
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, USA
| | - Marieke Bronk
- Department of Clinical Genetics and Genome Analysis, Academic Medical Center, Amsterdam, Netherlands
| | - Stephanie Oprescu
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Fred van Ruissen
- Department of Clinical Genetics and Genome Analysis, Academic Medical Center, Amsterdam, Netherlands
| | | | | | - Martijn Breuning
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Camiel Verhamme
- Department of Neurology, Academic Medical Center, Amsterdam, Netherlands
| | - Ya-Ming Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, USA
| | - Marianne de Visser
- Department of Neurology, Academic Medical Center, Amsterdam, Netherlands
| | - Anthony Antonellis
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Frank Baas
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, Netherlands
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22
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Wei N, Zhang Q, Yang XL. Neurodegenerative Charcot-Marie-Tooth disease as a case study to decipher novel functions of aminoacyl-tRNA synthetases. J Biol Chem 2019; 294:5321-5339. [PMID: 30643024 DOI: 10.1074/jbc.rev118.002955] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes that catalyze the first reaction in protein biosynthesis, namely the charging of transfer RNAs (tRNAs) with their cognate amino acids. aaRSs have been increasingly implicated in dominantly and recessively inherited human diseases. The most common aaRS-associated monogenic disorder is the incurable neurodegenerative disease Charcot-Marie-Tooth neuropathy (CMT), caused by dominant mono-allelic mutations in aaRSs. With six currently known members (GlyRS, TyrRS, AlaRS, HisRS, TrpRS, and MetRS), aaRSs represent the largest protein family implicated in CMT etiology. After the initial discovery linking aaRSs to CMT, the field has progressed from understanding whether impaired tRNA charging is a critical component of this disease to elucidating the specific pathways affected by CMT-causing mutations in aaRSs. Although many aaRS CMT mutants result in loss of tRNA aminoacylation function, animal genetics studies demonstrated that dominant mutations in GlyRS cause CMT through toxic gain-of-function effects, which also may apply to other aaRS-linked CMT subtypes. The CMT-causing mechanism is likely to be multifactorial and involves multiple cellular compartments, including the nucleus and the extracellular space, where the normal WT enzymes also appear. Thus, the association of aaRSs with neuropathy is relevant to discoveries indicating that aaRSs also have nonenzymatic regulatory functions that coordinate protein synthesis with other biological processes. Through genetic, functional, and structural analyses, commonalities among different mutations and different aaRS-linked CMT subtypes have begun to emerge, providing insights into the nonenzymatic functions of aaRSs and the pathogenesis of aaRS-linked CMT to guide therapeutic development to treat this disease.
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Affiliation(s)
- Na Wei
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
| | - Qian Zhang
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
| | - Xiang-Lei Yang
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
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23
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Fuchs SA, Schene IF, Kok G, Jansen JM, Nikkels PGJ, van Gassen KLI, Terheggen-Lagro SWJ, van der Crabben SN, Hoeks SE, Niers LEM, Wolf NI, de Vries MC, Koolen DA, Houwen RHJ, Mulder MF, van Hasselt PM. Aminoacyl-tRNA synthetase deficiencies in search of common themes. Genet Med 2018; 21:319-330. [PMID: 29875423 PMCID: PMC7091658 DOI: 10.1038/s41436-018-0048-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 04/10/2018] [Indexed: 12/22/2022] Open
Abstract
Purpose Pathogenic variations in genes encoding aminoacyl-tRNA synthetases (ARSs) are increasingly associated with human disease. Clinical features of autosomal recessive ARS deficiencies appear very diverse and without apparent logic. We searched for common clinical patterns to improve disease recognition, insight into pathophysiology, and clinical care. Methods Symptoms were analyzed in all patients with recessive ARS deficiencies reported in literature, supplemented with unreported patients evaluated in our hospital. Results In literature, we identified 107 patients with AARS, DARS, GARS, HARS, IARS, KARS, LARS, MARS, RARS, SARS, VARS, YARS, and QARS deficiencies. Common symptoms (defined as present in ≥4/13 ARS deficiencies) included abnormalities of the central nervous system and/or senses (13/13), failure to thrive, gastrointestinal symptoms, dysmaturity, liver disease, and facial dysmorphisms. Deep phenotyping of 5 additional patients with unreported compound heterozygous pathogenic variations in IARS, LARS, KARS, and QARS extended the common phenotype with lung disease, hypoalbuminemia, anemia, and renal tubulopathy. Conclusion We propose a common clinical phenotype for recessive ARS deficiencies, resulting from insufficient aminoacylation activity to meet translational demand in specific organs or periods of life. Assuming residual ARS activity, adequate protein/amino acid supply seems essential instead of the traditional replacement of protein by glucose in patients with metabolic diseases.
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Affiliation(s)
- Sabine A Fuchs
- Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands.
| | - Imre F Schene
- Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands
| | - Gautam Kok
- Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands
| | - Jurriaan M Jansen
- Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands
| | - Peter G J Nikkels
- Department of Pathology, University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands
| | - Koen L I van Gassen
- Department of Genetics, University Medical Centre Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands
| | - Suzanne W J Terheggen-Lagro
- Department of Pediatric Pulmonology, Academic Medical Center Amsterdam, Meibergdreef 9, Amsterdam, 1105 AZ, The Netherlands
| | - Saskia N van der Crabben
- Department of Clinical Genetics, VU University Medical Center, De Boelelaan 1117, Amsterdam, 1081HV, The Netherlands
| | - Sanne E Hoeks
- Department of Neonatology, University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands
| | - Laetitia E M Niers
- Department of Pediatrics, Maxima Medical Centre Veldhoven, De Run 4600, Veldhoven, 5504 DB, The Netherlands
| | - Nicole I Wolf
- Department of Child Neurology, VU University Medical Center, De Boelelaan 1117, Amsterdam, 1081HV, The Netherlands
| | - Maaike C de Vries
- Nijmegen Centre for Mitochondrial Disorders at Department of Pediatrics, Radboud University Nijmegen Centre, Nijmegen, The Netherlands
| | - David A Koolen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, 6500 HB, The Netherlands
| | - Roderick H J Houwen
- Division of Pediatric Gastroenterology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands
| | - Margot F Mulder
- Department of Pediatrics, VU University Medical Center, De Boelelaan 1117, Amsterdam, 1081HV, The Netherlands
| | - Peter M van Hasselt
- Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Lundlaan 6, Utrecht, 3584 EA, The Netherlands
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24
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Boczonadi V, Jennings MJ, Horvath R. The role of tRNA synthetases in neurological and neuromuscular disorders. FEBS Lett 2018; 592:703-717. [PMID: 29288497 PMCID: PMC5873386 DOI: 10.1002/1873-3468.12962] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/06/2017] [Accepted: 12/21/2017] [Indexed: 12/11/2022]
Abstract
Aminoacyl‐tRNA synthetases (ARSs) are ubiquitously expressed enzymes responsible for charging tRNAs with their cognate amino acids, therefore essential for the first step in protein synthesis. Although the majority of protein synthesis happens in the cytosol, an additional translation apparatus is required to translate the 13 mitochondrial DNA‐encoded proteins important for oxidative phosphorylation. Most ARS genes in these cellular compartments are distinct, but two genes are common, encoding aminoacyl‐tRNA synthetases of glycine (GARS) and lysine (KARS) in both mitochondria and the cytosol. Mutations in the majority of the 37 nuclear‐encoded human ARS genes have been linked to a variety of recessive and dominant tissue‐specific disorders. Current data indicate that impaired enzyme function could explain the pathogenicity, however not all pathogenic ARSs mutations result in deficient catalytic function; thus, the consequences of mutations may arise from other molecular mechanisms. The peripheral nerves are frequently affected, as illustrated by the high number of mutations in cytosolic and bifunctional tRNA synthetases causing Charcot–Marie–Tooth disease (CMT). Here we provide insights on the pathomechanisms of CMT‐causing tRNA synthetases with specific focus on the two bifunctional tRNA synthetases (GARS, KARS).
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Affiliation(s)
- Veronika Boczonadi
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Matthew J Jennings
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Rita Horvath
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
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25
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Meyer-Schuman R, Antonellis A. Emerging mechanisms of aminoacyl-tRNA synthetase mutations in recessive and dominant human disease. Hum Mol Genet 2017; 26:R114-R127. [PMID: 28633377 PMCID: PMC5886470 DOI: 10.1093/hmg/ddx231] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 06/09/2017] [Accepted: 06/12/2017] [Indexed: 12/29/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) are responsible for charging amino acids to cognate tRNA molecules, which is the essential first step of protein translation. Interestingly, mutations in genes encoding ARS enzymes have been implicated in a broad spectrum of human inherited diseases. Bi-allelic mutations in ARSs typically cause severe, early-onset, recessive diseases that affect a wide range of tissues. The vast majority of these mutations show loss-of-function effects and impair protein translation. However, it is not clear how a subset cause tissue-specific phenotypes. In contrast, dominant ARS-mediated diseases specifically affect the peripheral nervous system-most commonly causing axonal peripheral neuropathy-and usually manifest later in life. These neuropathies are linked to heterozygosity for missense mutations in five ARS genes, which points to a shared mechanism of disease. However, it is not clear if a loss-of-function mechanism or a toxic gain-of-function mechanism is responsible for ARS-mediated neuropathy, or if a combination of these mechanisms operate on a mutation-specific basis. Here, we review our current understanding of recessive and dominant ARS-mediated disease. We also propose future directions for defining the molecular mechanisms of ARS mutations toward designing therapies for affected patient populations.
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Affiliation(s)
- Rebecca Meyer-Schuman
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Anthony Antonellis
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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26
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Amornvit J, Yalvac ME, Chen L, Sahenk Z. A novel p.T139M mutation in HSPB1 highlighting the phenotypic spectrum in a family. Brain Behav 2017; 7:e00774. [PMID: 28828227 PMCID: PMC5561327 DOI: 10.1002/brb3.774] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 06/13/2017] [Indexed: 12/20/2022] Open
Abstract
INTRODUCTION Mutations in the HSPB1 gene encoding the small heat shock protein B1 are associated with an autosomal dominant, axonal form of Charcot-Marie-Tooth disease 2F (CMT2F) and distal hereditary motor neuropathy. Recently, distal myopathy had been described in a patient carrying HSPB1 mutation adding to the complexity of phenotypes resulting from HSPB1 mutations. METHODS Five patients in a family with concerns of hereditary neuropathy were included. Detailed clinical examinations, including assessments of motor and sensory function, and electrophysiological data were obtained. Genetic analysis was requested through a commercial laboratory. In vitro studies were carried out to assess the pathogenicity of the novel mutation found in this family studies. RESULTS All patients carried a novel mutation, c.146 C>T (p.T139M), substitution in the α-crystallin domain of HSPB1 causing a clinical phenotype with hyperreflexia and intrafamilial variability, from muscle cramps as the only presenting symptom to a classic CMT phenotype. In vitro studies showed that cells expressing HSPB1-T139M displayed decreased cell viability with increased expression of apoptosis markers. Moreover, overexpression of the mutant, not the wild-type HSPB1, caused formation of congophilic aggregates. CONCLUSIONS In vitro findings strongly support the pathogenicity of this novel mutation. We propose that Congo red histochemical stain may serve as a simple screening tool for investigating if the aggregates in mutant cells have misfolded β-pleated sheet secondary structures.
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Affiliation(s)
- Jakkrit Amornvit
- Center for Gene Therapy The Research Institute at Nationwide Children's Hospital Columbus OH USA.,King Chulalongkorn Memorial Hospital and Department of Medicine Faculty of Medicine Chulalongkorn University Bangkok Thailand
| | - Mehmet E Yalvac
- Center for Gene Therapy The Research Institute at Nationwide Children's Hospital Columbus OH USA
| | - Lei Chen
- Center for Gene Therapy The Research Institute at Nationwide Children's Hospital Columbus OH USA
| | - Zarife Sahenk
- Center for Gene Therapy The Research Institute at Nationwide Children's Hospital Columbus OH USA.,Department of Pediatrics and Neurology Nationwide Children's Hospital and The Ohio State University Columbus OH USA.,Department of Pathology and Laboratory Medicine Nationwide Children's Hospital Columbus OH USA
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27
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Ognjenović J, Simonović M. Human aminoacyl-tRNA synthetases in diseases of the nervous system. RNA Biol 2017; 15:623-634. [PMID: 28534666 PMCID: PMC6103678 DOI: 10.1080/15476286.2017.1330245] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 05/05/2017] [Accepted: 05/10/2017] [Indexed: 12/21/2022] Open
Abstract
Aminoacyl-tRNA synthetases (AaRSs) are ubiquitously expressed enzymes that ensure accurate translation of the genetic information into functional proteins. These enzymes also execute a variety of non-canonical functions that are significant for regulation of diverse cellular processes and that reside outside the realm of protein synthesis. Associations between faults in AaRS-mediated processes and human diseases have been long recognized. Most recent research findings strongly argue that 10 cytosolic and 14 mitochondrial AaRSs are implicated in some form of pathology of the human nervous system. The advent of modern whole-exome sequencing makes it all but certain that similar associations between the remaining 15 ARS genes and neurologic illnesses will be defined in future. It is not surprising that an intense scientific debate about the role of translational machinery, in general, and AaRSs, in particular, in the development and maintenance of the healthy human neural cell types and the brain is sparked. Herein, we summarize the current knowledge about causative links between mutations in human AaRSs and diseases of the nervous system and briefly discuss future directions.
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Affiliation(s)
- Jana Ognjenović
- Department of Biochemistry and Molecular Genetics, College of Medicine, The University of Illinois at Chicago, Chicago, IL, USA
| | - Miljan Simonović
- Department of Biochemistry and Molecular Genetics, College of Medicine, The University of Illinois at Chicago, Chicago, IL, USA
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28
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Nakayama T, Wu J, Galvin-Parton P, Weiss J, Andriola MR, Hill RS, Vaughan DJ, El-Quessny M, Barry BJ, Partlow JN, Barkovich AJ, Ling J, Mochida GH. Deficient activity of alanyl-tRNA synthetase underlies an autosomal recessive syndrome of progressive microcephaly, hypomyelination, and epileptic encephalopathy. Hum Mutat 2017; 38:1348-1354. [PMID: 28493438 DOI: 10.1002/humu.23250] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 04/27/2017] [Accepted: 05/06/2017] [Indexed: 02/03/2023]
Abstract
Aminoacyl-transfer RNA (tRNA) synthetases ligate amino acids to specific tRNAs and are essential for protein synthesis. Although alanyl-tRNA synthetase (AARS) is a synthetase implicated in a wide range of neurological disorders from Charcot-Marie-Tooth disease to infantile epileptic encephalopathy, there have been limited data on their pathogenesis. Here, we report loss-of-function mutations in AARS in two siblings with progressive microcephaly with hypomyelination, intractable epilepsy, and spasticity. Whole-exome sequencing identified that the affected individuals were compound heterozygous for mutations in AARS gene, c.2067dupC (p.Tyr690Leufs*3) and c.2738G>A (p.Gly913Asp). A lymphoblastoid cell line developed from one of the affected individuals showed a strong reduction in AARS abundance. The mutations decrease aminoacylation efficiency by 70%-90%. The p.Tyr690Leufs*3 mutation also abolished editing activity required for hydrolyzing misacylated tRNAs, thereby increasing errors during aminoacylation. Our study has extended potential mechanisms underlying AARS-related disorders to include destabilization of the protein, aminoacylation dysfunction, and defective editing activity.
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Affiliation(s)
- Tojo Nakayama
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts.,Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts
| | - Jiang Wu
- Department of Microbiology and Molecular Genetics, Medical School, University of Texas Health Science Center, Houston, Texas
| | | | - Jody Weiss
- Department of Pediatrics, Stony Brook University Medical Center, Stony Brook, New York
| | - Mary R Andriola
- Department of Pediatrics, Stony Brook University Medical Center, Stony Brook, New York
| | - R Sean Hill
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts.,Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts.,Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts
| | - Dylan J Vaughan
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts.,Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts
| | - Malak El-Quessny
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts.,Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts
| | - Brenda J Barry
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts.,Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts.,Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts
| | - Jennifer N Partlow
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts.,Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts.,Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts
| | - A James Barkovich
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California
| | - Jiqiang Ling
- Department of Microbiology and Molecular Genetics, Medical School, University of Texas Health Science Center, Houston, Texas.,Graduate School of Biomedical Sciences, Houston, Texas
| | - Ganeshwaran H Mochida
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, Massachusetts.,Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.,Pediatric Neurology Unit, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts
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29
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Oprescu SN, Griffin LB, Beg AA, Antonellis A. Predicting the pathogenicity of aminoacyl-tRNA synthetase mutations. Methods 2016; 113:139-151. [PMID: 27876679 DOI: 10.1016/j.ymeth.2016.11.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 11/12/2016] [Accepted: 11/18/2016] [Indexed: 10/24/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) are ubiquitously expressed, essential enzymes responsible for charging tRNA with cognate amino acids-the first step in protein synthesis. ARSs are required for protein translation in the cytoplasm and mitochondria of all cells. Surprisingly, mutations in 28 of the 37 nuclear-encoded human ARS genes have been linked to a variety of recessive and dominant tissue-specific disorders. Current data indicate that impaired enzyme function is a robust predictor of the pathogenicity of ARS mutations. However, experimental model systems that distinguish between pathogenic and non-pathogenic ARS variants are required for implicating newly identified ARS mutations in disease. Here, we outline strategies to assist in predicting the pathogenicity of ARS variants and urge cautious evaluation of genetic and functional data prior to linking an ARS mutation to a human disease phenotype.
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Affiliation(s)
- Stephanie N Oprescu
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Laurie B Griffin
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, United States; Medical Scientist Training Program, and University of Michigan Medical School, Ann Arbor, MI, United States
| | - Asim A Beg
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Anthony Antonellis
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, United States; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, United States.
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30
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Storkebaum E. Peripheral neuropathy via mutant tRNA synthetases: Inhibition of protein translation provides a possible explanation. Bioessays 2016; 38:818-29. [PMID: 27352040 PMCID: PMC5094542 DOI: 10.1002/bies.201600052] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recent evidence indicates that inhibition of protein translation may be a common pathogenic mechanism for peripheral neuropathy associated with mutant tRNA synthetases (aaRSs). aaRSs are enzymes that ligate amino acids to their cognate tRNA, thus catalyzing the first step of translation. Dominant mutations in five distinct aaRSs cause Charcot‐Marie‐Tooth (CMT) peripheral neuropathy, characterized by length‐dependent degeneration of peripheral motor and sensory axons. Surprisingly, loss of aminoacylation activity is not required for mutant aaRSs to cause CMT. Rather, at least for some mutations, a toxic‐gain‐of‐function mechanism underlies CMT‐aaRS. Interestingly, several mutations in two distinct aaRSs were recently shown to inhibit global protein translation in Drosophila models of CMT‐aaRS, by a mechanism independent of aminoacylation, suggesting inhibition of translation as a common pathogenic mechanism. Future research aimed at elucidating the molecular mechanisms underlying the translation defect induced by CMT‐mutant aaRSs should provide novel insight into the molecular pathogenesis of these incurable diseases.
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Affiliation(s)
- Erik Storkebaum
- Molecular Neurogenetics Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany.,Faculty of Medicine, University of Münster, Münster, Germany
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31
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Abstract
Myeloneuropathy is a frequently encountered condition and often poses a diagnostic challenge. A variety of nutritional, toxic, metabolic, infective, inflammatory, and paraneoplastic disorders can present with myeloneuropathy. Deficiencies of vitamin B12, folic acid, copper, and vitamin E may lead to myeloneuropathy with a clinical picture of subacute combined degeneration of the spinal cord. Among infective causes, chikungunya virus has been shown to produce a syndrome similar to myeloneuropathy. Vacuolar myelopathy seen in human immunodeficiency virus (HIV) infection is clinically very similar to subacute combined degeneration. A paraneoplastic myeloneuropathy, an immune-mediated disorder associated with an underlying malignancy, may rarely be seen with breast cancer. Tropical myeloneuropathies are classified into two overlapping clinical entities — tropical ataxic neuropathy and tropical spastic paraparesis. Tropical spastic paraparesis, a chronic noncompressive myelopathy, has frequently been reported from South India. Establishing the correct diagnosis of myeloneuropathy is important because compressive myelopathies may pose diagnostic confusion. Magnetic resonance imaging (MRI) in subacute combined degeneration of the spinal cord typically reveals characteristic signal changes on T2-weighted images of the cervical spinal cord. Once the presence of myeloneuropathy is established, all these patients should be subjected to a battery of tests. Blood levels of vitamin B12, folic acid, vitamins A, D, E, and K, along with levels of iron, methylmalonic acid, homocysteine, and calcium should be assessed. The pattern of neurologic involvement and results obtained from a battery of biochemical tests often help in establishing the correct diagnosis.
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Affiliation(s)
- Ravindra Kumar Garg
- Department of Neurology, King George Medical University, Lucknow, Uttar Pradesh, India
| | | | - Neeraj Kumar
- Department of Neurology, King George Medical University, Lucknow, Uttar Pradesh, India
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32
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Bansagi B, Antoniadi T, Burton-Jones S, Murphy SM, McHugh J, Alexander M, Wells R, Davies J, Hilton-Jones D, Lochmüller H, Chinnery P, Horvath R. Genotype/phenotype correlations in AARS-related neuropathy in a cohort of patients from the United Kingdom and Ireland. J Neurol 2015; 262:1899-908. [PMID: 26032230 PMCID: PMC4539360 DOI: 10.1007/s00415-015-7778-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 05/05/2015] [Accepted: 05/06/2015] [Indexed: 01/24/2023]
Abstract
Charcot-Marie-Tooth disease (CMT) is the most common inherited neuropathy with heterogeneous clinical presentation and genetic background. The axonal form (CMT2) is characterised by decreased action potentials indicating primary axonal damage. The underlying pathology involves axonal degeneration which is supposed to be related to axonal protein dysfunction caused by various gene mutations. The overlapping clinical manifestation of CMT2 with distal hereditary motor neuropathy (dHMN) and intermediate CMT causes further diagnostic difficulties. Aminoacyl-tRNA synthetases have been implicated in the pathomechanism of CMT2. They have an essential role in protein translation by attaching amino acids to their cognate tRNAs. To date six families have been reported worldwide with dominant missense alanyl-tRNA synthetase (AARS) mutations leading to clinically heterogeneous axonal neuropathies. The pathomechanism of some variants could be explained by impaired amino acylation activity while other variants implicating an editing defect need to be further investigated. Here, we report a cohort of six additional families originating from the United Kingdom and Ireland with dominant AARS-related neuropathies. The phenotypic manifestation was distal lower limb predominant sensorimotor neuropathy but upper limb impairment with split hand deformity occasionally associated. Nerve conduction studies revealed significant demyelination accompanying the axonal lesion in motor and sensory nerves. Five families have the c.986G>A, p.(Arg329His) variant, further supporting that this is a recurrent loss of function variant. The sixth family, of Irish origin, had a novel missense variant, c.2063A>G, p.(Glu688Gly). We discuss our findings and the associated phenotypic heterogeneity in these families, which expands the clinical spectrum of AARS-related neuropathies.
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Affiliation(s)
- Boglarka Bansagi
- John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
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