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Li B, Liu F, Chen X, Chen T, Zhang J, Liu Y, Yao Y, Hu W, Zhang M, Wang B, Liu L, Chen K, Wu Y. FARS2 Deficiency Causes Cardiomyopathy by Disrupting Mitochondrial Homeostasis and the Mitochondrial Quality Control System. Circulation 2024; 149:1268-1284. [PMID: 38362779 PMCID: PMC11017836 DOI: 10.1161/circulationaha.123.064489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 12/13/2023] [Indexed: 02/17/2024]
Abstract
BACKGROUND Hypertrophic cardiomyopathy (HCM) is a common heritable heart disease. Although HCM has been reported to be associated with many variants of genes involved in sarcomeric protein biomechanics, pathogenic genes have not been identified in patients with partial HCM. FARS2 (the mitochondrial phenylalanyl-tRNA synthetase), a type of mitochondrial aminoacyl-tRNA synthetase, plays a role in the mitochondrial translation machinery. Several variants of FARS2 have been suggested to cause neurological disorders; however, FARS2-associated diseases involving other organs have not been reported. We identified FARS2 as a potential novel pathogenic gene in cardiomyopathy and investigated its effects on mitochondrial homeostasis and the cardiomyopathy phenotype. METHODS FARS2 variants in patients with HCM were identified using whole-exome sequencing, Sanger sequencing, molecular docking analyses, and cell model investigation. Fars2 conditional mutant (p.R415L) or knockout mice, fars2-knockdown zebrafish, and Fars2-knockdown neonatal rat ventricular myocytes were engineered to construct FARS2 deficiency models both in vivo and in vitro. The effects of FARS2 and its role in mitochondrial homeostasis were subsequently evaluated using RNA sequencing and mitochondrial functional analyses. Myocardial tissues from patients were used for further verification. RESULTS We identified 7 unreported FARS2 variants in patients with HCM. Heart-specific Fars2-deficient mice presented cardiac hypertrophy, left ventricular dilation, progressive heart failure accompanied by myocardial and mitochondrial dysfunction, and a short life span. Heterozygous cardiac-specific Fars2R415L mice displayed a tendency to cardiac hypertrophy at age 4 weeks, accompanied by myocardial dysfunction. In addition, fars2-knockdown zebrafish presented pericardial edema and heart failure. FARS2 deficiency impaired mitochondrial homeostasis by directly blocking the aminoacylation of mt-tRNAPhe and inhibiting the synthesis of mitochondrial proteins, ultimately contributing to an imbalanced mitochondrial quality control system by accelerating mitochondrial hyperfragmentation and disrupting mitochondrion-related autophagy. Interfering with the mitochondrial quality control system using adeno-associated virus 9 or specific inhibitors mitigated the cardiac and mitochondrial dysfunction triggered by FARS2 deficiency by restoring mitochondrial homeostasis. CONCLUSIONS Our findings unveil the previously unrecognized role of FARS2 in heart and mitochondrial homeostasis. This study may provide new insights into the molecular diagnosis and prevention of heritable cardiomyopathy as well as therapeutic options for FARS2-associated cardiomyopathy.
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Affiliation(s)
- Bowen Li
- Department of Biochemistry and Molecular Biology, Shaanxi Provincial Key Laboratory of Clinical Genetics (B.L., X.C., T.C., J.Z., Y.L., Y.Y., W.H., M.Z., Y.W.), Air Force Medical University, Xi’an, China
| | - Fangfang Liu
- Department of Neurobiology (F.L.), Air Force Medical University, Xi’an, China
| | - Xihui Chen
- Department of Biochemistry and Molecular Biology, Shaanxi Provincial Key Laboratory of Clinical Genetics (B.L., X.C., T.C., J.Z., Y.L., Y.Y., W.H., M.Z., Y.W.), Air Force Medical University, Xi’an, China
| | - Tangdong Chen
- Department of Biochemistry and Molecular Biology, Shaanxi Provincial Key Laboratory of Clinical Genetics (B.L., X.C., T.C., J.Z., Y.L., Y.Y., W.H., M.Z., Y.W.), Air Force Medical University, Xi’an, China
| | - Juan Zhang
- Department of Biochemistry and Molecular Biology, Shaanxi Provincial Key Laboratory of Clinical Genetics (B.L., X.C., T.C., J.Z., Y.L., Y.Y., W.H., M.Z., Y.W.), Air Force Medical University, Xi’an, China
| | - Yifeng Liu
- Department of Biochemistry and Molecular Biology, Shaanxi Provincial Key Laboratory of Clinical Genetics (B.L., X.C., T.C., J.Z., Y.L., Y.Y., W.H., M.Z., Y.W.), Air Force Medical University, Xi’an, China
| | - Yan Yao
- Department of Biochemistry and Molecular Biology, Shaanxi Provincial Key Laboratory of Clinical Genetics (B.L., X.C., T.C., J.Z., Y.L., Y.Y., W.H., M.Z., Y.W.), Air Force Medical University, Xi’an, China
| | - Weihong Hu
- Department of Biochemistry and Molecular Biology, Shaanxi Provincial Key Laboratory of Clinical Genetics (B.L., X.C., T.C., J.Z., Y.L., Y.Y., W.H., M.Z., Y.W.), Air Force Medical University, Xi’an, China
| | - Mengjie Zhang
- Department of Biochemistry and Molecular Biology, Shaanxi Provincial Key Laboratory of Clinical Genetics (B.L., X.C., T.C., J.Z., Y.L., Y.Y., W.H., M.Z., Y.W.), Air Force Medical University, Xi’an, China
| | - Bo Wang
- School of Basic Medicine, Department of Ultrasound, Xijing Hypertrophic Cardiomyopathy Center, Xijing Hospital (B.W., L.L.), Air Force Medical University, Xi’an, China
| | - Liwen Liu
- School of Basic Medicine, Department of Ultrasound, Xijing Hypertrophic Cardiomyopathy Center, Xijing Hospital (B.W., L.L.), Air Force Medical University, Xi’an, China
| | - Kun Chen
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Center (K.C.), Air Force Medical University, Xi’an, China
| | - Yuanming Wu
- Department of Biochemistry and Molecular Biology, Shaanxi Provincial Key Laboratory of Clinical Genetics (B.L., X.C., T.C., J.Z., Y.L., Y.Y., W.H., M.Z., Y.W.), Air Force Medical University, Xi’an, China
- Department of Clinical Laboratory, Tangdu Hospital (Y.W.), Air Force Medical University, Xi’an, China
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Zhang X, Xiang F, Li D, Yang F, Yu S, Wang X. Adult-onset combined oxidative phosphorylation deficiency type 14 manifests as epileptic status: a new phenotype and literature review. BMC Neurol 2024; 24:15. [PMID: 38166857 PMCID: PMC10759640 DOI: 10.1186/s12883-023-03480-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 11/27/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Combined oxidative phosphorylation deficiency (COXPD) is a severe disorder with early onset and autosomal recessive inheritance, and has been divided into 51 types (COXPD1-COXPD51). COXPD14 is caused by a mutation in the FARS2 gene, which encodes mitochondrial phenylalanyl-tRNA synthetase (mt-PheRS), an enzyme that transfers phenylalanine to its cognate tRNA in mitochondria. Since the first case was reported in 2012, an increasing number of FARS2 variations have been subsequently identified, which present three main phenotypic manifestations: early onset epileptic encephalopathy, hereditary spastic paraplegia, and juvenile-onset epilepsy. To our knowledge, no adult cases have been reported in the literature. METHODS We report in detail a case of genetically confirmed COXPD14 and review the relevant literature. RESULTS Approximately 58 subjects with disease-causing variants of FARS2 have been reported, including 31 cases of early onset epileptic encephalopathy, 16 cases of hereditary spastic paraplegia, 3 cases of juvenile-onset epilepsy, and 8 cases of unknown phenotype. We report a case of autosomal recessive COXPD14 in an adult with status epilepticus as the only manifestation with a good prognosis, which is different from that in neonatal or infant patients reported in the literature. c.467C > T (p.T156M) has been previously reported, while c.119_120del (p.E40Vfs*87) is novel, and, both mutations are pathogenic. CONCLUSIONS This case of autosomal recessive COXPD14 in an adult only presented as status epilepticus, which is different from the patients reported previously. Our study expands the mutation spectrum of FARS2, and we tended to define the phenotypes based on the clinical manifestation rather than the age of onset.
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Affiliation(s)
- Xu Zhang
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, 28# Fuxing Road, Beijing, People's Republic of China
| | - Feng Xiang
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, 28# Fuxing Road, Beijing, People's Republic of China
| | - Desheng Li
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, 28# Fuxing Road, Beijing, People's Republic of China
| | - Fei Yang
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, 28# Fuxing Road, Beijing, People's Republic of China
| | - Shengyuan Yu
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, 28# Fuxing Road, Beijing, People's Republic of China
| | - Xiangqing Wang
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, 28# Fuxing Road, Beijing, People's Republic of China.
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Chen W, Rehsi P, Thompson K, Yeo M, Stals K, He L, Schimmel P, Chrzanowska-Lightowlers ZMA, Wakeling E, Taylor RW, Kuhle B. Clinical and molecular characterization of novel FARS2 variants causing neonatal mitochondrial disease. Mol Genet Metab 2023; 140:107657. [PMID: 37523899 DOI: 10.1016/j.ymgme.2023.107657] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/22/2023] [Accepted: 07/22/2023] [Indexed: 08/02/2023]
Abstract
FARS2 encodes the mitochondrial phenylalanyl-tRNA synthetase (mtPheRS), which is essential for charging mitochondrial (mt-) tRNAPhe with phenylalanine for use in intramitochondrial translation. Many biallelic, pathogenic FARS2 variants have been described previously, which are mostly associated with two distinct clinical phenotypes; an early onset epileptic mitochondrial encephalomyopathy or a later onset spastic paraplegia. In this study, we report on a patient who presented at 3 weeks of age with tachypnoea and poor feeding, which progressed to severe metabolic decompensation with lactic acidosis and seizure activity followed by death at 9 weeks of age. Rapid trio whole exome sequencing identified compound heterozygous FARS2 variants including a pathogenic exon 2 deletion on one allele and a rare missense variant (c.593G > T, p.(Arg198Leu)) on the other allele, necessitating further work to aid variant classification. Assessment of patient fibroblasts demonstrated severely decreased steady-state levels of mtPheRS, but no obvious defect in any components of the oxidative phosphorylation system. To investigate the potential pathogenicity of the missense variant, we determined its high-resolution crystal structure, demonstrating a local structural destabilization in the catalytic domain. Moreover, the R198L mutation reduced the thermal stability and impaired the enzymatic activity of mtPheRS due to a lower binding affinity for tRNAPhe and a slower turnover rate. Together these data confirm the pathogenicity of this FARS2 variant in causing early-onset mitochondrial epilepsy.
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Affiliation(s)
- Wenqian Chen
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Preeya Rehsi
- Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Kyle Thompson
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK
| | - Mildrid Yeo
- Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Karen Stals
- Exeter Genomics Laboratory, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Langping He
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne NE1 4LP, UK
| | - Paul Schimmel
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA; The Scripps Florida Research Institute at the University of Florida, Jupiter, FL 33458, USA
| | - Zofia M A Chrzanowska-Lightowlers
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK
| | - Emma Wakeling
- North East Thames Regional Genetic Service, Great Ormond Street Hospital NHS Foundation Trust, London, UK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne NE1 4LP, UK.
| | - Bernhard Kuhle
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA; Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen 37073, Germany.
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Kong LY, Wu YZ, Cheng RQ, Wang PH, Peng BW. Role of Mutations of Mitochondrial Aminoacyl-tRNA Synthetases Genes on Epileptogenesis. Mol Neurobiol 2023; 60:5482-5492. [PMID: 37316759 DOI: 10.1007/s12035-023-03429-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 06/05/2023] [Indexed: 06/16/2023]
Abstract
Mitochondria are the structures in cells that are responsible for producing energy. They contain a specific translation unit for synthesizing mitochondria-encoded respiratory chain components: the mitochondrial DNA (mt DNA). Recently, a growing number of syndromes associated with the dysfunction of mt DNA translation have been reported. However, the functions of these diseases still need to be precise and thus attract much attention. Mitochondrial tRNAs (mt tRNAs) are encoded by mt DNA; they are the primary cause of mitochondrial dysfunction and are associated with a wide range of pathologies. Previous research has shown the role of mt tRNAs in the epileptic mechanism. This review will focus on the function of mt tRNA and the role of mitochondrial aminoacyl-tRNA synthetase (mt aaRS) in order to summarize some common relevant mutant genes of mt aaRS that cause epilepsy and the specific symptoms of the disease they cause.
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Affiliation(s)
- Ling-Yue Kong
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Yi-Ze Wu
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Run-Qi Cheng
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Pei-Han Wang
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Bi-Wen Peng
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China.
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, School of Basic Medical Sciences, Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China.
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Fink JK. The hereditary spastic paraplegias. HANDBOOK OF CLINICAL NEUROLOGY 2023; 196:59-88. [PMID: 37620092 DOI: 10.1016/b978-0-323-98817-9.00022-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
The hereditary spastic paraplegias (HSPs) are a group of more than 90 genetic disorders in which lower extremity spasticity and weakness are either the primary neurologic impairments ("uncomplicated HSP") or when accompanied by other neurologic deficits ("complicated HSP"), important features of the clinical syndrome. Various genetic types of HSP are inherited such as autosomal dominant, autosomal recessive, X-linked, and maternal (mitochondrial) traits. Symptoms that begin in early childhood may be nonprogressive and resemble spastic diplegic cerebral palsy. Symptoms that begin later, typically progress insidiously over a number of years. Genetic testing is able to confirm the diagnosis for many subjects. Insights from gene discovery indicate that abnormalities in diverse molecular processes underlie various forms of HSP, including disturbance in axon transport, endoplasmic reticulum morphogenesis, vesicle transport, lipid metabolism, and mitochondrial function. Pathologic studies in "uncomplicated" HSP have shown axon degeneration particularly involving the distal ends of corticospinal tracts and dorsal column fibers. Treatment is limited to symptom reduction including amelioration of spasticity, reducing urinary urgency, proactive physical therapy including strengthening, stretching, balance, and agility exercise.
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Affiliation(s)
- John K Fink
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.
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Ng YS, McFarland R. Mitochondrial encephalomyopathy. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:563-585. [PMID: 37562887 DOI: 10.1016/b978-0-323-98818-6.00025-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Mitochondrial dysfunction, especially perturbation of oxidative phosphorylation and adenosine triphosphate (ATP) generation, disrupts cellular homeostasis and is a surprisingly frequent cause of central and peripheral nervous system pathology. Mitochondrial disease is an umbrella term that encompasses a host of clinical syndromes and features caused by in excess of 300 different genetic defects affecting the mitochondrial and nuclear genomes. Patients with mitochondrial disease can present at any age, ranging from neonatal onset to late adult life, with variable organ involvement and neurological manifestations including neurodevelopmental delay, seizures, stroke-like episodes, movement disorders, optic neuropathy, myopathy, and neuropathy. Until relatively recently, analysis of skeletal muscle biopsy was the focus of diagnostic algorithms, but step-changes in the scope and availability of next-generation sequencing technology and multiomics analysis have revolutionized mitochondrial disease diagnosis. Currently, there is no specific therapy for most types of mitochondrial disease, although clinical trials research in the field is gathering momentum. In that context, active management of epilepsy, stroke-like episodes, dystonia, brainstem dysfunction, and Parkinsonism are all the more important in improving patient quality of life and reducing mortality.
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Affiliation(s)
- Yi Shiau Ng
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom.
| | - Robert McFarland
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
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Gong X, Liu L, Li X, Xiong J, Xu J, Mao D, Liu L. Neuroprotection of cannabidiol in epileptic rats: Gut microbiome and metabolome sequencing. Front Nutr 2022; 9:1028459. [PMID: 36466385 PMCID: PMC9709218 DOI: 10.3389/fnut.2022.1028459] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 10/31/2022] [Indexed: 07/30/2023] Open
Abstract
AIMS Epilepsy is a neurological disease occurring worldwide. Alterations in the gut microbial composition may be involved in the development of Epilepsy. The study aimed to investigate the effects of cannabidiol (CBD) on gut microbiota and the metabolic profile of epileptic rats. MATERIALS AND METHODS AND RESULTS A temporal lobe epilepsy rat model was established using Li-pilocarpine. CBD increased the incubation period and reduced the epileptic state in rats. Compared to epileptic rats, the M1/M2 ratio of microglia in the CBD group was significantly decreased. The expression of IL-1β, IL-6, and TNF-α in the CBD group decreased, while IL-10, IL-4, and TGF-β1 increased. 16S rDNA sequencing revealed that the ANOSIM index differed significantly between the groups. At the genus level, Helicobacter, Prevotellaceae_UCG-001, and Ruminococcaceae_UCG-005 were significantly reduced in the model group. CBD intervention attenuated the intervention effects of Li-pilocarpine. Roseburia, Eubacterium_xylanophilum_group, and Ruminococcus_2 were strongly positively correlated with proinflammatory cytokine levels. CBD reversed dysregulated metabolites, including glycerophosphocholine and 4-ethylbenzoic acid. CONCLUSION CBD could alleviate the dysbiosis of gut microbiota and metabolic disorders of epileptic rats. CBD attenuated Epilepsy in rats might be related to gut microbial abundance and metabolite levels. SIGNIFICANCE AND IMPACT OF STUDY The study may provide a reliable scientific clue to explore the regulatory pathway of CBD in alleviating Epilepsy.
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Affiliation(s)
- Xiaoxiang Gong
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Children’s Brain Development and Brain Injury Research Office, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lingjuan Liu
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Children’s Brain Development and Brain Injury Research Office, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xingfang Li
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Children’s Brain Development and Brain Injury Research Office, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jie Xiong
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Children’s Brain Development and Brain Injury Research Office, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jie Xu
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Children’s Brain Development and Brain Injury Research Office, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Dingan Mao
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Children’s Brain Development and Brain Injury Research Office, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Liqun Liu
- Department of Pediatrics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
- Children’s Brain Development and Brain Injury Research Office, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
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Li L, Ma J, Wang J, Dong L, Liu S. Two Chinese siblings of combined oxidative phosphorylation deficiency 14 caused by compound heterozygous variants in FARS2. Eur J Med Res 2022; 27:184. [PMID: 36155627 PMCID: PMC9511728 DOI: 10.1186/s40001-022-00808-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 09/01/2022] [Indexed: 11/10/2022] Open
Abstract
Background As a rare mitochondrial disease, combined oxidative phosphorylation deficiency 14 (COXPD14) is caused by biallelic variants in the phenylalanyl-tRNA synthetase 2, mitochondrial gene (FARS2) with clinical features of developmental delay, an elevated lactate level, early-onset encephalopathy, liver failure, and hypotonia. The objectives of this study were to analyze the clinical and molecular features of two Chinese siblings affected with COXPD14, and to review relevant literature. Methods Mutation screening was performed by whole exome sequencing (WES) in combination with Sanger sequencing validation to identify the disease-causing variants of the two patients. Results The two siblings presented with severe clinical features and both progressed aggressively and failed to survive after treatment abandonment. We identified two compound heterozygous FARS2 variants c.925G>A p.Gly309Ser and c.943G>C p.Gly315Arg in this proband, which were inherited from the unaffected father and mother, respectively. In addition, Sanger sequencing confirmed that the elder affected sister carried the same compound heterozygous variants. The c.925G>A p.Gly309Ser variant is known and commonly reported in COXPD14 patients, while c.943G>C p.Gly315Arg is a novel one. Neither of the variants was found in 100 Chinese healthy controls. Both variants were classified as “deleterious” and were located in the highly conserved regions of the protein. The above results suggested that the two variants were likely causative in this COXPD14-affected pedigree. Conclusions Our study expands the mutation spectrum of FARS2 and highlights the importance of genetic testing in the diagnosis of diseases with a wide variety of phenotypes, especially in the differential diagnosis of diseases.
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Affiliation(s)
- Liangshan Li
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
| | - Jianhua Ma
- Department of Reproductive Medicine, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Jingli Wang
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
| | - Liping Dong
- Neonatal Disease Screening Center, Zibo Maternal and Child Health Hospital, Zibo, 255000, China.
| | - Shiguo Liu
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China.
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Brabec JL, Ouardouz M, Mahoney JM, Scott RC, Hernan AE. Differential regulation of gene expression pathways with dexamethasone and ACTH after early life seizures. Neurobiol Dis 2022; 174:105873. [PMID: 36152945 PMCID: PMC10048589 DOI: 10.1016/j.nbd.2022.105873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 10/31/2022] Open
Abstract
Early-life seizures (ELS) are associated with persistent cognitive deficits such as ADHD and memory impairment. These co-morbidities have a dramatic negative impact on the quality of life of patients. Therapies that improve cognitive outcomes have enormous potential to improve patients' quality of life. Our previous work in a rat flurothyl-induction model showed that administration of adrenocorticotropic hormone (ACTH) at time of seizure induction led to improved learning and memory in the animals despite no effect on seizure latency or duration. Administration of dexamethasone (Dex), a corticosteroid, did not have the same positive effect on learning and memory and has even been shown to exacerbate injury in a rat model of temporal lobe epilepsy. We hypothesized that ACTH exerted positive effects on cognitive outcomes through beneficial changes to gene expression and proposed that administration of ACTH at seizure induction would return gene-expression in the brain towards the normal pattern of expression in the Control animals whereas Dex would not. Twenty-six Sprague-Dawley rats were randomized into vehicle- Control, and ACTH-, Dex-, and vehicle- ELS. Rat pups were subjected to 60 flurothyl seizures from P5 to P14. After seizure induction, brains were removed and the hippocampus and PFC were dissected, RNA was extracted and sequenced, and differential expression analysis was performed using generalized estimating equations. Differential expression analysis showed that ACTH pushes gene expression in the brain back to a more normal state of expression through enrichment of pathways involved in supporting homeostatic balance and down-regulating pathways that might contribute to excitotoxic cell-damage post-ELS.
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Affiliation(s)
- Jeffrey L Brabec
- University of Vermont, Department of Neurological Sciences, 149 Beaumont Avenue, Burlington, VT 05401, USA.
| | - Mohamed Ouardouz
- Nemours Children's Health, Division of Neuroscience, 1600 Rockland Road, Wilmington, DE 19803, USA
| | - J Matthew Mahoney
- University of Vermont, Department of Neurological Sciences, 149 Beaumont Avenue, Burlington, VT 05401, USA; The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Rod C Scott
- Nemours Children's Health, Division of Neuroscience, 1600 Rockland Road, Wilmington, DE 19803, USA; Neurosciences Unit University College London, Institute of Child Health, London WC1N 1EH, UK; University of Delaware, Psychological and Brain Sciences, South College Avenue, Newark, DE 19716, USA
| | - Amanda E Hernan
- Nemours Children's Health, Division of Neuroscience, 1600 Rockland Road, Wilmington, DE 19803, USA; University of Delaware, Psychological and Brain Sciences, South College Avenue, Newark, DE 19716, USA
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Abstract
The human brain consumes five orders of magnitude more energy than the sun by unit of mass and time. This staggering bioenergetic cost serves mostly synaptic transmission and actin cytoskeleton dynamics. The peak of both brain bioenergetic demands and the age of onset for neurodevelopmental disorders is approximately 5 years of age. This correlation suggests that defects in the machinery that provides cellular energy would be causative and/or consequence of neurodevelopmental disorders. We explore this hypothesis from the perspective of the machinery required for the synthesis of the electron transport chain, an ATP-producing and NADH-consuming enzymatic cascade. The electron transport chain is constituted by nuclear- and mitochondrial-genome-encoded subunits. These subunits are synthesized by the 80S and the 55S ribosomes, which are segregated to the cytoplasm and the mitochondrial matrix, correspondingly. Mitochondrial protein synthesis by the 55S ribosome is the rate-limiting step in the synthesis of electron transport chain components, suggesting that mitochondrial protein synthesis is a bottleneck for tissues with high bionergetic demands. We discuss genetic defects in the human nuclear and mitochondrial genomes that affect these protein synthesis machineries and cause a phenotypic spectrum spanning autism spectrum disorders to neurodegeneration during neurodevelopment. We propose that dysregulated mitochondrial protein synthesis is a chief, yet understudied, causative mechanism of neurodevelopmental and behavioral disorders.
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Chen X, Liu F, Li B, Wang Y, Yuan L, Yin A, Chen Q, Hu W, Yao Y, Zhang M, Wu Y, Chen K. Neuropathy-associated Fars2 deficiency affects neuronal development and potentiates neuronal apoptosis by impairing mitochondrial function. Cell Biosci 2022; 12:103. [PMID: 35794642 PMCID: PMC9258231 DOI: 10.1186/s13578-022-00838-y] [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: 04/23/2022] [Accepted: 06/23/2022] [Indexed: 11/22/2022] Open
Abstract
Background Neurodegenerative diseases encompass an extensive and heterogeneous group of nervous system disorders which are characterized by progressive degeneration and death of neurons. Many lines of evidence suggest the participation of mitochondria dysfunction in these diseases. Mitochondrial phenylalanyl-tRNA synthetase, encoded by FARS2, catalyzes the transfer of phenylalanine to its cognate tRNA for protein synthesis. As a member of mt-aaRSs genes, FARS2 missense homozygous mutation c.424G > T (p.D142Y) found in a Chinese consanguineous family first built the relationship between pure hereditary spastic paraplegia (HSP) and FARS2 gene. More FARS2 variations were subsequently found to cause heterogeneous group of neurologic disorders presenting three main phenotypic manifestations: infantile-onset epileptic mitochondrial encephalopathy, later-onset spastic paraplegia and juvenile onset refractory epilepsy. Studies showed that aminoacylation activity is frequently disrupt in cases with FARS2 mutations, indicating a loss-of-function mechanism. However, the underlying pathogenesis of neuropathy-associated Fars2 deficiency is still largely unknown. Results Early gestation lethality of global Fars2 knockout mice was observed prior to neurogenesis. The conditional Fars2 knockout-mouse model delayed lethality to late-gestation, resulting in a thinner cortex and an enlarged ventricle which is consist with the MRI results revealing cortical atrophy and reduced cerebral white matter volume in FARS2-deficient patients. Delayed development of neurite outgrowth followed by neuronal apoptosis was confirmed in Fars2-knockdown mouse primary cultured neurons. Zebrafish, in which fars2 was knocked down, exhibited aberrant motor neuron function including reduced locomotor capacity which well restored the spastic paraplegia phenotype of FARS2-deficient patients. Altered mitochondrial protein synthesis and reduced levels of oxidative phosphorylation complexes were detected in Fars2-deficient samples. And thus, reduced ATP, total NAD levels and mitochondrial membrane potential, together with increased ROS production, revealed mitochondrial dysfunction both in vitro and in vivo. Dctn3 is a potential downstream molecule in responds to Fars2 deficient in neurons, which may provide some evidence for the development of pathogenesis study and therapeutic schedule. Conclusions The Fars2 deficiency genetic models developed in this study cover the typical clinical manifestations in FARS2 patients, and help clarify how neuropathy-associated Fars2 deficiency, by damaging the mitochondrial respiratory chain and impairing mitochondrial function, affects neuronal development and potentiates neuronal cell apoptosis. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-022-00838-y.
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Affiliation(s)
- Xihui Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Fangfang Liu
- Department of Neurobiology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Bowen Li
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Yufeng Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Medical Genetics, Yan'an University, Yan'an, Shaanxi, People's Republic of China
| | - Lijuan Yuan
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Department of General Surgery, Tangdu Hospital, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Anan Yin
- Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Department of Plastic surgery, Xijing Hospital, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Qi Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Weihong Hu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Medical Genetics, Yan'an University, Yan'an, Shaanxi, People's Republic of China
| | - Yan Yao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Medical Genetics, Yan'an University, Yan'an, Shaanxi, People's Republic of China
| | - Mengjie Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Medical Genetics, Yan'an University, Yan'an, Shaanxi, People's Republic of China
| | - YuanMing Wu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China. .,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.
| | - Kun Chen
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.
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12
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Malone TJ, Kaczmarek LK. The role of altered translation in intellectual disability and epilepsy. Prog Neurobiol 2022; 213:102267. [PMID: 35364140 PMCID: PMC10583652 DOI: 10.1016/j.pneurobio.2022.102267] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 02/18/2022] [Accepted: 03/24/2022] [Indexed: 11/29/2022]
Abstract
A very high proportion of cases of intellectual disability are genetic in origin and are associated with the occurrence of epileptic seizures during childhood. These two disorders together effect more than 5% of the world's population. One feature linking the two diseases is that learning and memory require the synthesis of new synaptic components and ion channels, while maintenance of overall excitability also requires synthesis of similar proteins in response to altered neuronal stimulation. Many of these disorders result from mutations in proteins that regulate mRNA processing, translation initiation, translation elongation, mRNA stability or upstream translation modulators. One theme that emerges on reviewing this field is that mutations in proteins that regulate changes in translation following neuronal stimulation are more likely to result in epilepsy with intellectual disability than general translation regulators with no known role in activity-dependent changes. This is consistent with the notion that activity-dependent translation in neurons differs from that in other cells types in that the changes in local cellular composition, morphology and connectivity that occur generally in response to stimuli are directly coupled to local synaptic activity and persist for months or years after the original stimulus.
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Affiliation(s)
- Taylor J Malone
- Departments of Pharmacology, and of Cellular & Molecular Physiology, Yale University, 333 Cedar Street B-309, New Haven, CT 06520, USA
| | - Leonard K Kaczmarek
- Departments of Pharmacology, and of Cellular & Molecular Physiology, Yale University, 333 Cedar Street B-309, New Haven, CT 06520, USA.
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13
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Fan W, Jin X, Xu M, Xi Y, Lu W, Yang X, Guan MX, Ge W. FARS2 deficiency in Drosophila reveals the developmental delay and seizure manifested by aberrant mitochondrial tRNA metabolism. Nucleic Acids Res 2021; 49:13108-13121. [PMID: 34878141 PMCID: PMC8682739 DOI: 10.1093/nar/gkab1187] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 11/08/2021] [Accepted: 11/17/2021] [Indexed: 01/16/2023] Open
Abstract
Mutations in genes encoding mitochondrial aminoacyl-tRNA synthetases are linked to diverse diseases. However, the precise mechanisms by which these mutations affect mitochondrial function and disease development are not fully understood. Here, we develop a Drosophila model to study the function of dFARS2, the Drosophila homologue of the mitochondrial phenylalanyl–tRNA synthetase, and further characterize human disease-associated FARS2 variants. Inactivation of dFARS2 in Drosophila leads to developmental delay and seizure. Biochemical studies reveal that dFARS2 is required for mitochondrial tRNA aminoacylation, mitochondrial protein stability, and assembly and enzyme activities of OXPHOS complexes. Interestingly, by modeling FARS2 mutations associated with human disease in Drosophila, we provide evidence that expression of two human FARS2 variants, p.G309S and p.D142Y, induces seizure behaviors and locomotion defects, respectively. Together, our results not only show the relationship between dysfunction of mitochondrial aminoacylation system and pathologies, but also illustrate the application of Drosophila model for functional analysis of human disease-causing variants.
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Affiliation(s)
- Wenlu Fan
- Division of Human Reproduction and Developmental Genetics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China.,Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, China
| | - Xiaoye Jin
- Division of Human Reproduction and Developmental Genetics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China.,Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, China
| | - Man Xu
- Division of Human Reproduction and Developmental Genetics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China.,Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, China
| | - Yongmei Xi
- Division of Human Reproduction and Developmental Genetics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China
| | - Weiguo Lu
- Department of Gynecologic Oncology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, China.,Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xiaohang Yang
- Division of Human Reproduction and Developmental Genetics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China.,Zhejiang Provincial Key Laboratory of Genetic and Developmental Disorders, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Min-Xin Guan
- Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China.,Zhejiang Provincial Key Laboratory of Genetic and Developmental Disorders, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Wanzhong Ge
- Division of Human Reproduction and Developmental Genetics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China.,Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, China.,Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310058, China
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14
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Lin SJ, Vona B, Barbalho PG, Kaiyrzhanov R, Maroofian R, Petree C, Severino M, Stanley V, Varshney P, Bahena P, Alzahrani F, Alhashem A, Pagnamenta AT, Aubertin G, Estrada-Veras JI, Hernández HAD, Mazaheri N, Oza A, Thies J, Renaud DL, Dugad S, McEvoy J, Sultan T, Pais LS, Tabarki B, Villalobos-Ramirez D, Rad A, Galehdari H, Ashrafzadeh F, Sahebzamani A, Saeidi K, Torti E, Elloumi HZ, Mora S, Palculict TB, Yang H, Wren JD, Ben Fowler, Joshi M, Behra M, Burgess SM, Nath SK, Hanna MG, Kenna M, Merritt JL, Houlden H, Karimiani EG, Zaki MS, Haaf T, Alkuraya FS, Gleeson JG, Varshney GK. Biallelic variants in KARS1 are associated with neurodevelopmental disorders and hearing loss recapitulated by the knockout zebrafish. Genet Med 2021; 23:1933-1943. [PMID: 34172899 PMCID: PMC8956360 DOI: 10.1038/s41436-021-01239-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/20/2021] [Accepted: 05/24/2021] [Indexed: 12/04/2022] Open
Abstract
PURPOSE Pathogenic variants in Lysyl-tRNA synthetase 1 (KARS1) have increasingly been recognized as a cause of early-onset complex neurological phenotypes. To advance the timely diagnosis of KARS1-related disorders, we sought to delineate its phenotype and generate a disease model to understand its function in vivo. METHODS Through international collaboration, we identified 22 affected individuals from 16 unrelated families harboring biallelic likely pathogenic or pathogenic in KARS1 variants. Sequencing approaches ranged from disease-specific panels to genome sequencing. We generated loss-of-function alleles in zebrafish. RESULTS We identify ten new and four known biallelic missense variants in KARS1 presenting with a moderate-to-severe developmental delay, progressive neurological and neurosensory abnormalities, and variable white matter involvement. We describe novel KARS1-associated signs such as autism, hyperactive behavior, pontine hypoplasia, and cerebellar atrophy with prevalent vermian involvement. Loss of kars1 leads to upregulation of p53, tissue-specific apoptosis, and downregulation of neurodevelopmental related genes, recapitulating key tissue-specific disease phenotypes of patients. Inhibition of p53 rescued several defects of kars1-/- knockouts. CONCLUSION Our work delineates the clinical spectrum associated with KARS1 defects and provides a novel animal model for KARS1-related human diseases revealing p53 signaling components as potential therapeutic targets.
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Affiliation(s)
- Sheng-Jia Lin
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Barbara Vona
- Department of Otolaryngology-Head & Neck Surgery, Tübingen Hearing Research Centre, Eberhard Karls University of Tübingen, Tübingen, Germany.,Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Patricia G Barbalho
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Rauan Kaiyrzhanov
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Reza Maroofian
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Cassidy Petree
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | | | - Valentina Stanley
- Department of Neurosciences, Rady Children's Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Pratishtha Varshney
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Paulina Bahena
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Fatema Alzahrani
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Amal Alhashem
- Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Alistair T Pagnamenta
- NIHR Biomedical Research Centre, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Gudrun Aubertin
- Division of Medical Genetics, Department of Pathology and Lab Medicine, Island Health, Victoria General Hospital, Victoria, BC, Canada
| | - Juvianee I Estrada-Veras
- Henry M Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA.,Pediatric Subspecialty Genetics Walter Reed National Military Medical Center, Bethesda, MD, USA.,Murtha Cancer Center / Research Program, Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Héctor Adrián Díaz Hernández
- Department of Gastrointestinal Endoscopy, National Institute of Medical Sciences and Nutrition Salvador Zubirán, Mexico City, Mexico
| | - Neda Mazaheri
- Department of Genetics, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran.,Narges Medical Genetics and Prenatal Diagnostics Laboratory, East Mihan Ave., Kianpars, Iran
| | - Andrea Oza
- Otolaryngology and Communication Enhancement, Boston Children's Hospital, and Dept. of Otolaryngology, Harvard medical School, Boston, USA
| | - Jenny Thies
- Department of Biochemical Genetics, Seattle Children's Hospital, Seattle, WA, USA
| | - Deborah L Renaud
- Departments of Neurology and Pediatrics, Mayo Clinic College of Medicine and Science, Rochester, MN, USA
| | - Sanmati Dugad
- Bioinformatics Centre, S. P. Pune University, Pune, India
| | - Jennifer McEvoy
- Department of Neurosciences, Rady Children's Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Tipu Sultan
- Department of Pediatric Neurology, Children's Hospital and Institute of Child Health, Lahore, Pakistan
| | - Lynn S Pais
- Broad Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA, USA
| | - Brahim Tabarki
- Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | | | - Aboulfazl Rad
- Department of Otolaryngology-Head & Neck Surgery, Tübingen Hearing Research Centre, Eberhard Karls University of Tübingen, Tübingen, Germany
| | | | - Hamid Galehdari
- Department of Gastrointestinal Endoscopy, National Institute of Medical Sciences and Nutrition Salvador Zubirán, Mexico City, Mexico
| | - Farah Ashrafzadeh
- Department of Pediatric Diseases, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Afsaneh Sahebzamani
- Pediatric and Genetic Counselling Center, Kerman Welfare Organization, Kerman, Iran
| | - Kolsoum Saeidi
- Neuroscience Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Erin Torti
- GeneDx, 207 Perry Parkway Gaithersburg, Gaithersburg, MD, USA
| | - Houda Z Elloumi
- GeneDx, 207 Perry Parkway Gaithersburg, Gaithersburg, MD, USA
| | - Sara Mora
- GeneDx, 207 Perry Parkway Gaithersburg, Gaithersburg, MD, USA
| | | | - Hui Yang
- GeneDx, 207 Perry Parkway Gaithersburg, Gaithersburg, MD, USA
| | - Jonathan D Wren
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Ben Fowler
- Imaging core facility, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Manali Joshi
- Bioinformatics Centre, S. P. Pune University, Pune, India
| | - Martine Behra
- Department of Neurobiology, University of Puerto Rico, San Juan, PR, USA
| | - Shawn M Burgess
- Translational & Functional Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Swapan K Nath
- Arthritis & Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Michael G Hanna
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Margaret Kenna
- Otolaryngology and Communication Enhancement, Boston Children's Hospital, and Dept. of Otolaryngology, Harvard medical School, Boston, USA
| | - J Lawrence Merritt
- Department of Pediatrics, Biochemical Genetics, University of Washington, Seattle, WA, USA
| | - Henry Houlden
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Ehsan Ghayoor Karimiani
- Molecular and Clinical Sciences Institute, St. George's, University of London, Cranmer Terrace London, London, UK.,Innovative Medical Research Center, Mashhad Branch, Islamic Azdad University, Mashhad, Iran
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | - Thomas Haaf
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Joseph G Gleeson
- Department of Neurosciences, Rady Children's Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Gaurav K Varshney
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.
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15
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Novel FARS2 variants in patients with early onset encephalopathy with or without epilepsy associated with long survival. Eur J Hum Genet 2020; 29:533-538. [PMID: 33168986 DOI: 10.1038/s41431-020-00757-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 09/10/2020] [Accepted: 10/20/2020] [Indexed: 11/08/2022] Open
Abstract
Mitochondrial translation is essential for the biogenesis of the mitochondrial oxidative phosphorylation system (OXPHOS) that synthesizes the bulk of ATP for the cell. Hypomorphic and loss-of-function variants in either mitochondrial DNA or in nuclear genes that encode mitochondrial translation factors can result in impaired OXPHOS biogenesis and mitochondrial diseases with variable clinical presentations. Compound heterozygous or homozygous missense and frameshift variants in the FARS2 gene, that encodes the mitochondrial phenylalanyl-tRNA synthetase, are commonly linked to either early-onset epileptic mitochondrial encephalopathy or spastic paraplegia. Here, we expand the genetic spectrum of FARS2-linked disease with three patients carrying novel compound heterozygous variants in the FARS2 gene and presenting with spastic tetraparesis, axial hypotonia and myoclonic epilepsy in two cases.
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16
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Peretz M, Tworowski D, Kartvelishvili E, Livingston J, Chrzanowska-Lightowlers Z, Safro M. Breaking a single hydrogen bond in the mitochondrial tRNA Phe -PheRS complex leads to phenotypic pleiotropy of human disease. FEBS J 2020; 287:3814-3826. [PMID: 32115907 PMCID: PMC7540514 DOI: 10.1111/febs.15268] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 01/09/2020] [Accepted: 02/27/2020] [Indexed: 01/19/2023]
Abstract
Various pathogenic variants in both mitochondrial tRNAPhe and Phenylalanyl‐tRNA synthetase mitochondrial protein coding gene (FARS2) gene encoding for the human mitochondrial PheRS have been identified and associated with neurological and/or muscle‐related pathologies. An important Guanine‐34 (G34)A anticodon mutation associated with myoclonic epilepsy with ragged red fibers (MERRF) syndrome has been reported in hmit‐tRNAPhe. The majority of G34 contacts in available aaRSs‐tRNAs complexes specifically use that base as an important tRNA identity element. The network of intermolecular interactions providing its specific recognition also largely conserved. However, their conservation depends also on the invariance of the residues in the anticodon binding domain (ABD) of human mitochondrial Phenylalanyl‐tRNA synthetase (hmit‐PheRS). A defect in recognition of the anticodon of tRNAPhe may happen not only because of G34A mutation, but also due to mutations in the ABD. Indeed, a pathogenic mutation in FARS2 has been recently reported in a 9‐year‐old female patient harboring a p.Asp364Gly mutation. Asp364 is hydrogen bonded (HB) to G34 in WT hmit‐PheRS. Thus, there are two pathogenic variants disrupting HB between G34 and Asp364: one is associated with G34A mutation, and the other with Asp364Gly mutation. We have measured the rates of tRNAPhe aminoacylation catalyzed by WT hmit‐PheRS and mutant enzymes. These data ranked the residues making a HB with G34 according to their contribution to activity and the signal transduction pathway in the hmit‐PheRS‐tRNAPhe complex. Furthermore, we carried out extensive MD simulations to reveal the interdomain contact topology on the dynamic trajectories of the complex, and gaining insight into the structural and dynamic integrity effects of hmit‐PheRS complexed with tRNAPhe. Database Structural data are available in PDB database under the accession number(s): 3CMQ, 3TUP, 5MGH, 5MGV.
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Affiliation(s)
- Moshe Peretz
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Dmitry Tworowski
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | | | | | | | - Mark Safro
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
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17
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Meszarosova AU, Seeman P, Jencik J, Drabova J, Cibochova R, Stellmachova J, Safka Brozkova D. Two types of recessive hereditary spastic paraplegia in Roma patients in compound heterozygous state; no ethnically prevalent variant found. Neurosci Lett 2020; 721:134800. [PMID: 32007496 DOI: 10.1016/j.neulet.2020.134800] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 01/09/2020] [Accepted: 01/29/2020] [Indexed: 10/25/2022]
Abstract
Hereditary spastic paraplegia (HSP or SPG) is a group of rare upper motor neuron diseases. As some ethnically-specific, disease-causing homozygous variants were described in the Czech Roma population, we hypotesised that some prevalent HSP-causing variant could exist in this population. Eight Czech Roma patients were found in a large group of Czech patients with suspected HSP and were tested using gene panel massively parallel sequencing (MPS). Two of the eight were diagnosed with SPG11 and SPG77, respectively. The SPG77 patient manifests a pure HSP phenotype, which is unusual for this SPG type. Both patients are compound heterozygotes for two different variants in the SPG11 (c.1603-1G>A and del ex. 16-18) and FARS2 (c.1082C>T and del ex.1-2) genes respectively; the three variants are novel. In order to find a potential ethnically-specific, disease-causing variant for HSP, we tested the heterozygote frequency of these variants among 130 anonymised DNA samples of Czech Roma individuals without clinical signs of HSP (HPS-negative). A novel deletion of ex.16-18 in the SPG11 gene was found in a heterozygous state in one individual in the HSP-negative group. Haplotype analysis showed that this individual and the patient with SPG11 shared the same haplotype. This supports the assumption that the identified SPG11 deletion could be a founder mutation in the Czech Roma population. In some Roma patients the disease may also be caused by two different biallelic pathogenic mutations.
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Affiliation(s)
- Anna Uhrova Meszarosova
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine Charles University and University Hospital Motol, Prague, Czech Republic.
| | - Pavel Seeman
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine Charles University and University Hospital Motol, Prague, Czech Republic
| | - Jan Jencik
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine Charles University and University Hospital Motol, Prague, Czech Republic
| | - Jana Drabova
- Department of Biology and Medical Genetics, 2nd Faculty of Medicine Charles University and University Hospital Motol, Prague, Czech Republic
| | - Renata Cibochova
- Department of Paediatric Neurology, 2nd Faculty of Medicine Charles University and University Hospital Motol, Prague, Czech Republic
| | - Julia Stellmachova
- Department of Medical Genetics, Palacky University Hospital, Olomouc, Czech Republic
| | - Dana Safka Brozkova
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine Charles University and University Hospital Motol, Prague, Czech Republic
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18
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Holt IJ. The mitochondrial R-loop. Nucleic Acids Res 2019; 47:5480-5489. [PMID: 31045202 PMCID: PMC6582354 DOI: 10.1093/nar/gkz277] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/11/2019] [Accepted: 04/29/2019] [Indexed: 12/18/2022] Open
Abstract
The DNA in mitochondria contributes essential components of the organelle’s energy producing machinery that is essential for life. In 1971, many mitochondrial DNA molecules were found to have a third strand of DNA that maps to a region containing critical regulatory elements for transcription and replication. Forty-five years later, a third strand of RNA in the same region has been reported. This mitochondrial R-loop is present on thousands of copies of mitochondrial DNA per cell making it potentially the most abundant R-loop in nature. Here, I assess the discovery of the mitochondrial R-loop, discuss why it remained unrecognized for almost half a century and propose for it central roles in the replication, organization and expression of mitochondrial DNA, which if compromised can lead to disease states.
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Affiliation(s)
- Ian J Holt
- Biodonostia Health Research Institute, 20014 San Sebastián, Spain & IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain.,Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London, NW3 2PF, UK.,CIBERNED (Center for Networked Biomedical Research on Neurodegenerative Diseases, Ministry of Economy and Competitiveness, Institute Carlos III), Madrid, Spain
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19
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Matricardi S, Canafoglia L, Ardissone A, Moroni I, Ragona F, Ghezzi D, Lamantea E, Nardocci N, Franceschetti S, Granata T. Epileptic phenotypes in children with early-onset mitochondrial diseases. Acta Neurol Scand 2019; 140:184-193. [PMID: 31102535 DOI: 10.1111/ane.13130] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 05/02/2019] [Accepted: 05/14/2019] [Indexed: 12/17/2022]
Abstract
OBJECTIVES To determine the prevalence of epilepsy in children with early-onset mitochondrial diseases (MDs) and to evaluate the epileptic phenotypes and associated features. MATERIALS AND METHODS Children affected by MD with onset during the first year of life were enrolled. Patients were classified according to their mitochondrial phenotype, and all findings in patients with epilepsy versus patients without were compared. The epileptic features were analyzed. RESULTS The series includes 129 patients (70 females) with median age at disease onset of 3 months. The median time of follow-up was 5 years. Non-syndromic mitochondrial encephalopathy and pyruvate dehydrogenase complex deficiency were the main mitochondrial diseases associated with epilepsy (P < 0.05). Seizures occurred in 48%, and the presence of epilepsy was significantly associated with earlier age at disease onset, presence of perinatal manifestations, and early detection of developmental delay and regression (P < 0.001). Epileptic encephalopathy (EE) with spasms and EE with prominent focal seizures were the most detected epileptic syndromes (37% and 27.4%). Several seizure types were recorded in 53.2%, with the unusual association of generalized and focal epileptic pattern. Disabling epilepsy was detected in 63% and was associated with early seizure onset, presence of several seizure types, epileptic syndrome featuring EE, and the recurrence of episodes of status epilepticus and epilepsia partialis continua (P < 0.05). CONCLUSIONS Epilepsy in children with early-onset MD may be a presenting or a prominent symptom in a multisystemic clinical presentation. Epilepsy-related factors could determine a worst seizure outcome, leading to a more severe burned of the disease.
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Affiliation(s)
- Sara Matricardi
- Department of Pediatric Neuroscience Fondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
- Department of Neuropsychiatry Children's Hospital “G. Salesi”Ospedali Riuniti Ancona Ancona Italy
| | - Laura Canafoglia
- Department of Neurophysiology and Diagnostic Epileptology Fondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Anna Ardissone
- Department of Pediatric Neuroscience Fondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Isabella Moroni
- Department of Pediatric Neuroscience Fondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Francesca Ragona
- Department of Pediatric Neuroscience Fondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Daniele Ghezzi
- Medical Genetics and Neurogenetics Fondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
- Department of Pathophysiology and Transplantation University of Milan Milan Italy
| | - Eleonora Lamantea
- Medical Genetics and Neurogenetics Fondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Nardo Nardocci
- Department of Pediatric Neuroscience Fondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Silvana Franceschetti
- Department of Neurophysiology and Diagnostic Epileptology Fondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
| | - Tiziana Granata
- Department of Pediatric Neuroscience Fondazione IRCCS Istituto Neurologico Carlo Besta Milan Italy
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20
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Chen Z, Zhang Y. A patient with juvenile-onset refractory status epilepticus caused by two novel compound heterozygous mutations in FARS2 gene. Int J Neurosci 2019; 129:1094-1097. [PMID: 31329004 DOI: 10.1080/00207454.2019.1634071] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
FARS2 encodes mitochondrial phenylalanyl transfer ribonucleic acid (RNA) synthetase and is implicated in autosomal recessive combined oxidative phosphorylation deficiency 14. The clinical manifestation can be divided into early onset epileptic phenotype and spastic paraplegia phenotype. The purpose of this study was to report a case of juvenile manifesting refractory epilepsy caused by two novel compound heterozygous mutations in the FARS2 gene. Microscopic and histochemical examination as well as next-generation sequencing and reconstruction of the three-dimensional structure of FARS2 protein were performed. A 17-year-old man with no developmental delays suffered from generalized tonic-clonic convulsion since 12 years of age and developed refractory status epilepticus 5 years later. No specific etiology was found following brain imaging, muscle biopsy and metabolic studies. DNA sequencing identified two novel compound heterozygous mutations in FARS2, (p.V197M and p.F402S), derived from each parents, respectively. These mutations affected the structure or thermodynamic stability of the protein. This is a case report of juvenile-onset refractory epilepsy caused by two novel compound heterozygous mutations in the FARS2 gene. This case confirms and expands the clinicalphenotype and the genotypic spectrum of the FARS2 gene.
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Affiliation(s)
- Zhongyun Chen
- Department of Neurology, Xuanwu Hospital, Capital Medical University , Beijing , China
| | - Yan Zhang
- Department of Neurology, Xuanwu Hospital, Capital Medical University , Beijing , China
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21
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Chakraborty S, Ibba M, Banerjee R. Biophysical characterization Of Alpers encephalopathy associated mutants of human mitochondrial phenylalanyl-tRNA synthetase. IUBMB Life 2019; 71:1141-1149. [PMID: 31241862 DOI: 10.1002/iub.2114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 06/06/2019] [Indexed: 12/13/2022]
Abstract
Mutations in nucleus-encoded mitochondrial aminoacyl-tRNA synthetases (mitaaRSs) lead to defects in mitochondrial translation affecting the expression and function of 13 subunits of the respiratory chain complex leading to diverse pathological conditions. Mutations in the FARS2 gene encoding human mitochondrial phenylalanyl-tRNA synthetase (HsmitPheRS) have been found to be associated with two different clinical representations, infantile Alpers encephalopathy and spastic paraplegia. Here we have studied three pathogenic mutants (Tyr144Cys, Ile329Thr, and Asp391Val) associated with Alpers encephalopathy to understand how these variants affect the biophysical properties of the enzyme. These mutants have already been reported to have reduced aminoacylation activity. Our study established that the mutants are significantly more thermolabile compared to the wild-type enzyme with reduced solubility in vitro. The presence of aggregation-prone insoluble HsmitPheRS variants could have a detrimental impact on organellar translation, and potentially impact normal mitochondrial function. © 2019 IUBMB Life, 71(8): 1141-1149, 2019 © 2019 IUBMB Life, 71(8):1141-1149, 2019.
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Affiliation(s)
- Shruti Chakraborty
- Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata, India
| | - Michael Ibba
- Department of Microbiology, The Ohio State University, Columbus, Ohio
| | - Rajat Banerjee
- Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata, India
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22
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Durigon R, Mitchell AL, Jones AW, Manole A, Mennuni M, Hirst EM, Houlden H, Maragni G, Lattante S, Doronzio PN, Dalla Rosa I, Zollino M, Holt IJ, Spinazzola A. LETM1 couples mitochondrial DNA metabolism and nutrient preference. EMBO Mol Med 2019; 10:emmm.201708550. [PMID: 30012579 PMCID: PMC6127893 DOI: 10.15252/emmm.201708550] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The diverse clinical phenotypes of Wolf–Hirschhorn syndrome (WHS) are the result of haploinsufficiency of several genes, one of which, LETM1, encodes a protein of the mitochondrial inner membrane of uncertain function. Here, we show that LETM1 is associated with mitochondrial ribosomes, is required for mitochondrial DNA distribution and expression, and regulates the activity of an ancillary metabolic enzyme, pyruvate dehydrogenase. LETM1 deficiency in WHS alters mitochondrial morphology and DNA organization, as does substituting ketone bodies for glucose in control cells. While this change in nutrient availability leads to the death of fibroblasts with normal amounts of LETM1, WHS‐derived fibroblasts survive on ketone bodies, which can be attributed to their reduced dependence on glucose oxidation. Thus, remodeling of mitochondrial nucleoprotein complexes results from the inability of mitochondria to use specific substrates for energy production and is indicative of mitochondrial dysfunction. However, the dysfunction could be mitigated by a modified diet—for WHS, one high in lipids and low in carbohydrates.
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Affiliation(s)
- Romina Durigon
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | - Alice L Mitchell
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | - Aleck We Jones
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | - Andreea Manole
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK.,Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Mara Mennuni
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | | | - Henry Houlden
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK.,Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | | | - Serena Lattante
- Institute of Genomic Medicine, Catholic University, Rome, Italy
| | | | - Ilaria Dalla Rosa
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK
| | | | - Ian J Holt
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK.,Biodonostia Health Research Institute, San Sebastián, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Antonella Spinazzola
- Department of Clinical and Movement Neurosciences, UCL Institute of Neurology, London, UK .,MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
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23
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Itkis Y, Krylova T, Pechatnikova NL, De Grassi A, Tabakov VY, Pierri CL, Aleshin V, Boyko A, Bunik VI, Zakharova EY. A novel variant m.641A>T in the mitochondrial MT-TF gene is associated with epileptic encephalopathy in adolescent. Mitochondrion 2019; 47:10-17. [PMID: 31009750 DOI: 10.1016/j.mito.2019.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 03/21/2019] [Accepted: 04/17/2019] [Indexed: 01/15/2023]
Abstract
We present a 14-year-old girl with loss of motor functions, tetraplegia, epilepsy and nystagmus, caused by a novel heteroplasmic m.641A>T transition in an evolutionary conserved region of mitochondrial genome, affecting the aminoacyl stem of mitochondrial tRNA-Phe. In silico prediction, respirometry, Western blot and enzymatic analyses in skin fibroblasts support the pathogenicity of the m.641A>T substitution. This is the 18th MT-TF point mutation associated with a mitochondrial disorder. The onset and the severity of the disease, however, is unique in this case and broadens the clinical picture related to mutations of mitochondrial tRNA-Phe.
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Affiliation(s)
- Yulia Itkis
- Department of Inborn Errors of Metabolism, FSBI 'Research Centre for Medical Genetics', Moscow, Russia.
| | - Tatiana Krylova
- Department of Inborn Errors of Metabolism, FSBI 'Research Centre for Medical Genetics', Moscow, Russia
| | | | - Anna De Grassi
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Vyacheslav Yu Tabakov
- Common Use Center "Biobank", FSBI 'Research Centre for Medical Genetics", Moscow, Russia
| | - Ciro Leonardo Pierri
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, Bari, Italy
| | - Vasily Aleshin
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia; Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Alexandra Boyko
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
| | - Victoria I Bunik
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia; Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Ekaterina Yu Zakharova
- Department of Inborn Errors of Metabolism, FSBI 'Research Centre for Medical Genetics', Moscow, Russia
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24
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Zhou Z, Austin GL, Young LEA, Johnson LA, Sun R. Mitochondrial Metabolism in Major Neurological Diseases. Cells 2018; 7:E229. [PMID: 30477120 PMCID: PMC6316877 DOI: 10.3390/cells7120229] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 11/19/2018] [Accepted: 11/21/2018] [Indexed: 01/18/2023] Open
Abstract
Mitochondria are bilayer sub-cellular organelles that are an integral part of normal cellular physiology. They are responsible for producing the majority of a cell's ATP, thus supplying energy for a variety of key cellular processes, especially in the brain. Although energy production is a key aspect of mitochondrial metabolism, its role extends far beyond energy production to cell signaling and epigenetic regulation⁻functions that contribute to cellular proliferation, differentiation, apoptosis, migration, and autophagy. Recent research on neurological disorders suggest a major metabolic component in disease pathophysiology, and mitochondria have been shown to be in the center of metabolic dysregulation and possibly disease manifestation. This review will discuss the basic functions of mitochondria and how alterations in mitochondrial activity lead to neurological disease progression.
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Affiliation(s)
- Zhengqiu Zhou
- Molecular & Cellular Biochemistry Department, University of Kentucky, Lexington, KY 40536, USA.
| | - Grant L Austin
- Molecular & Cellular Biochemistry Department, University of Kentucky, Lexington, KY 40536, USA.
| | - Lyndsay E A Young
- Molecular & Cellular Biochemistry Department, University of Kentucky, Lexington, KY 40536, USA.
| | - Lance A Johnson
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA.
| | - Ramon Sun
- Molecular & Cellular Biochemistry Department, University of Kentucky, Lexington, KY 40536, USA.
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25
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Vona B, Maroofian R, Bellacchio E, Najafi M, Thompson K, Alahmad A, He L, Ahangari N, Rad A, Shahrokhzadeh S, Bahena P, Mittag F, Traub F, Movaffagh J, Amiri N, Doosti M, Boostani R, Shirzadeh E, Haaf T, Diodato D, Schmidts M, Taylor RW, Karimiani EG. Expanding the clinical phenotype of IARS2-related mitochondrial disease. BMC MEDICAL GENETICS 2018; 19:196. [PMID: 30419932 PMCID: PMC6233262 DOI: 10.1186/s12881-018-0709-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 10/25/2018] [Indexed: 11/20/2022]
Abstract
Background IARS2 encodes a mitochondrial isoleucyl-tRNA synthetase, a highly conserved nuclear-encoded enzyme required for the charging of tRNAs with their cognate amino acid for translation. Recently, pathogenic IARS2 variants have been identified in a number of patients presenting broad clinical phenotypes with autosomal recessive inheritance. These phenotypes range from Leigh and West syndrome to a new syndrome abbreviated CAGSSS that is characterised by cataracts, growth hormone deficiency, sensory neuropathy, sensorineural hearing loss, and skeletal dysplasia, as well as cataract with no additional anomalies. Methods Genomic DNA from Iranian probands from two families with consanguineous parental background and overlapping CAGSSS features were subjected to exome sequencing and bioinformatics analysis. Results Exome sequencing and data analysis revealed a novel homozygous missense variant (c.2625C > T, p.Pro909Ser, NM_018060.3) within a 14.3 Mb run of homozygosity in proband 1 and a novel homozygous missense variant (c.2282A > G, p.His761Arg) residing in an ~ 8 Mb region of homozygosity in a proband of the second family. Patient-derived fibroblasts from proband 1 showed normal respiratory chain enzyme activity, as well as unchanged oxidative phosphorylation protein subunits and IARS2 levels. Homology modelling of the known and novel amino acid residue substitutions in IARS2 provided insight into the possible consequence of these variants on function and structure of the protein. Conclusions This study further expands the phenotypic spectrum of IARS2 pathogenic variants to include two patients (patients 2 and 3) with cataract and skeletal dysplasia and no other features of CAGSSS to the possible presentation of the defects in IARS2. Additionally, this study suggests that adult patients with CAGSSS may manifest central adrenal insufficiency and type II esophageal achalasia and proposes that a variable sensorineural hearing loss onset, proportionate short stature, polyneuropathy, and mild dysmorphic features are possible, as seen in patient 1. Our findings support that even though biallelic IARS2 pathogenic variants can result in a distinctive, clinically recognisable phenotype in humans, it can also show a wide range of clinical presentation from severe pediatric neurological disorders of Leigh and West syndrome to both non-syndromic cataract and cataract accompanied by skeletal dysplasia. Electronic supplementary material The online version of this article (10.1186/s12881-018-0709-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Barbara Vona
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany. .,Department of Otorhinolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre (THRC), Eberhard Karls University Tübingen, 72076, Tübingen, Germany.
| | - Reza Maroofian
- Genetics and Molecular Cell Sciences Research Centre, St George's, University of London, Cranmer Terrace, London, SW17 0RE, UK
| | - Emanuele Bellacchio
- Genetics and Rare Diseases, Research Division, 'Bambino Gesù' Children Hospital, Rome, Italy
| | - Maryam Najafi
- Genome Research Division, Human Genetics Department, Radboud University Medical Center and Radboud Institute for Molecular Life Sciences, Geert Grooteplein Zuid 10, 6525KL, Nijmegen, The Netherlands
| | - Kyle Thompson
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Ahmad Alahmad
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Langping He
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Najmeh Ahangari
- Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Next Generation Genetic Clinic, Mashhad, Iran
| | - Abolfazl Rad
- Genome Research Division, Human Genetics Department, Radboud University Medical Center and Radboud Institute for Molecular Life Sciences, Geert Grooteplein Zuid 10, 6525KL, Nijmegen, The Netherlands.,Cellular and Molecular Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | | | - Paulina Bahena
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Falk Mittag
- Department of Orthopaedic Surgery, University Hospital of Tübingen, Hoppe-Seyler-Strasse 3, 72076, Tübingen, Germany
| | - Frank Traub
- Department of Orthopaedic Surgery, University Hospital of Tübingen, Hoppe-Seyler-Strasse 3, 72076, Tübingen, Germany
| | - Jebrail Movaffagh
- Targeted Drug Delivery Research Center, Pharmaceutical Technology Institute, University of Medical Sciences, Mashhad, Iran
| | - Nafise Amiri
- Targeted Drug Delivery Research Center, Pharmaceutical Technology Institute, University of Medical Sciences, Mashhad, Iran
| | | | - Reza Boostani
- Department of Neurology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Thomas Haaf
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Daria Diodato
- Unit of Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, 'Bambino Gesu' Children's Research Hospital, Rome, Italy
| | - Miriam Schmidts
- Genome Research Division, Human Genetics Department, Radboud University Medical Center and Radboud Institute for Molecular Life Sciences, Geert Grooteplein Zuid 10, 6525KL, Nijmegen, The Netherlands.,Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Faculty of Medicine, Mathildenstrasse 1, 79112, Freiburg, Germany
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Ehsan Ghayoor Karimiani
- Genetics and Molecular Cell Sciences Research Centre, St George's, University of London, Cranmer Terrace, London, SW17 0RE, UK. .,Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
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26
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Almannai M, Wang J, Dai H, El-Hattab AW, Faqeih EA, Saleh MA, Al Asmari A, Alwadei AH, Aljadhai YI, AlHashem A, Tabarki B, Lines MA, Grange DK, Benini R, Alsaman AS, Mahmoud A, Katsonis P, Lichtarge O, Wong LJC. FARS2 deficiency; new cases, review of clinical, biochemical, and molecular spectra, and variants interpretation based on structural, functional, and evolutionary significance. Mol Genet Metab 2018; 125:281-291. [PMID: 30177229 DOI: 10.1016/j.ymgme.2018.07.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/25/2018] [Accepted: 07/25/2018] [Indexed: 02/07/2023]
Abstract
An increasing number of mitochondrial diseases are found to be caused by pathogenic variants in nuclear encoded mitochondrial aminoacyl-tRNA synthetases. FARS2 encodes mitochondrial phenylalanyl-tRNA synthetase (mtPheRS) which transfers phenylalanine to its cognate tRNA in mitochondria. Since the first case was reported in 2012, a total of 21 subjects with FARS2 deficiency have been reported to date with a spectrum of disease severity that falls between two phenotypes; early onset epileptic encephalopathy and a less severe phenotype characterized by spastic paraplegia. In this report, we present an additional 15 individuals from 12 families who are mostly Arabs homozygous for the pathogenic variant Y144C, which is associated with the more severe early onset phenotype. The total number of unique pathogenic FARS2 variants known to date is 21 including three different partial gene deletions reported in four individuals. Except for the large deletions, all variants but two (one in-frame deletion of one amino acid and one splice-site variant) are missense. All large deletions and the single splice-site variant are in trans with a missense variant. This suggests that complete loss of function may be incompatible with life. In this report, we also review structural, functional, and evolutionary significance of select FARS2 pathogenic variants reported here.
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Affiliation(s)
- Mohammed Almannai
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Julia Wang
- Medical Scientist Training Program and Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
| | - Hongzheng Dai
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Pediatric Department, Tawam Hospital, Al-Ain, United Arab Emirates
| | - Eissa A Faqeih
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Mohammed A Saleh
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Ali Al Asmari
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Ali H Alwadei
- Department of Pediatric Neurology, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Yaser I Aljadhai
- Department of Neuroimaging and Intervention, Medical Imaging Administration, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Amal AlHashem
- Department of Pediatric, Prince Sultan Medical Military City, Riyadh, Saudi Arabia; Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Brahim Tabarki
- Divisions of Pediatric Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Matthew A Lines
- Division of Metabolics and Newborn Screening, Children's Hospital of Eastern Ontario, Department of Pediatrics, Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Dorothy K Grange
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - Ruba Benini
- Department of Pediatric Neurology, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Abdulaziz S Alsaman
- Department of Pediatric Neurology, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Adel Mahmoud
- Department of Pediatric Neurology, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Panagiotis Katsonis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Olivier Lichtarge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Lee-Jun C Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
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27
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Sahai SK, Steiner RE, Au MG, Graham JM, Salamon N, Ibba M, Pierson TM. FARS2 mutations presenting with pure spastic paraplegia and lesions of the dentate nuclei. Ann Clin Transl Neurol 2018; 5:1128-1133. [PMID: 30250868 PMCID: PMC6144452 DOI: 10.1002/acn3.598] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/26/2018] [Accepted: 05/29/2018] [Indexed: 01/14/2023] Open
Abstract
Mutations in FARS2, the gene encoding the mitochondrial phenylalanine‐tRNA synthetase (mtPheRS), have been linked to a range of phenotypes including epileptic encephalopathy, developmental delay, and motor dysfunction. We report a 9‐year‐old boy with novel compound heterozygous variants of FARS2, presenting with a pure spastic paraplegia syndrome associated with bilateral signal abnormalities in the dentate nuclei. Exome sequencing identified a paternal nonsense variant (Q216X) lacking the catalytic core and anticodon‐binding regions, and a maternal missense variant (P136H) possessing partial enzymatic activity. This case confirms and expands the phenotype related to FARS2 mutations with regards to clinical presentation and neuroimaging findings.
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Affiliation(s)
- Supreet K Sahai
- Department of Neurology Cedars-Sinai Medical Center Los Angeles California
| | - Rebecca E Steiner
- Department of Microbiology Ohio State University Columbus Ohio 43210.,Center for RNA Biology Ohio State University Columbus Ohio 43210.,Ohio State Biochemistry Program Ohio State University Columbus Ohio 43210
| | - Margaret G Au
- Department of Pediatrics Cedars-Sinai Medical Center Los Angeles California
| | - John M Graham
- Department of Pediatrics Cedars-Sinai Medical Center Los Angeles California
| | - Noriko Salamon
- Department of Radiological Sciences David Geffen School of Medicine University of California Los Angeles Los Angeles California
| | - Michael Ibba
- Department of Microbiology Ohio State University Columbus Ohio 43210.,Center for RNA Biology Ohio State University Columbus Ohio 43210.,Ohio State Biochemistry Program Ohio State University Columbus Ohio 43210
| | - Tyler M Pierson
- Department of Neurology Cedars-Sinai Medical Center Los Angeles California.,Department of Pediatrics Cedars-Sinai Medical Center Los Angeles California.,Board of Governors Regenerative Medicine Institute Cedars-Sinai Medical Center Los Angeles California
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28
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Peycheva V, Kamenarova K, Ivanova N, Stamatov D, Avdjieva-Tzavella D, Alexandrova I, Zhelyazkova S, Pacheva I, Dimova P, Ivanov I, Litvinenko I, Bozhinova V, Tournev I, Simeonov E, Mitev V, Jordanova A, Kaneva R. Chromosomal microarray analysis of Bulgarian patients with epilepsy and intellectual disability. Gene 2018; 667:45-55. [DOI: 10.1016/j.gene.2018.05.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 04/13/2018] [Accepted: 05/03/2018] [Indexed: 12/08/2022]
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29
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Swaminathan A, Hassan-Abdi R, Renault S, Siekierska A, Riché R, Liao M, de Witte PAM, Yanicostas C, Soussi-Yanicostas N, Drapeau P, Samarut É. Non-canonical mTOR-Independent Role of DEPDC5 in Regulating GABAergic Network Development. Curr Biol 2018; 28:1924-1937.e5. [PMID: 29861134 DOI: 10.1016/j.cub.2018.04.061] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 02/13/2018] [Accepted: 04/17/2018] [Indexed: 01/19/2023]
Abstract
Mutations in DEPDC5 are causal factors for a broad spectrum of focal epilepsies, but the underlying pathogenic mechanisms are still largely unknown. To address this question, a zebrafish depdc5 knockout model showing spontaneous epileptiform events in the brain, increased drug-induced seizure susceptibility, general hypoactivity, premature death at 2-3 weeks post-fertilization, as well as the expected hyperactivation of mTOR signaling was developed. Using this model, the role of DEPDC5 in brain development was investigated using an unbiased whole-transcriptomic approach. Surprisingly, in addition to mTOR-associated genes, many genes involved in synaptic function, neurogenesis, axonogenesis, and GABA network activity were found to be dysregulated in larval brains. Although no gross defects in brain morphology or neuron loss were observed, immunostaining of depdc5-/- brains for several GABAergic markers revealed specific defects in the fine branching of the GABAergic network. Consistently, some defects in depdc5-/- could be compensated for by treatment with GABA, corroborating that GABA signaling is indeed involved in DEPDC5 pathogenicity. Further, the mTOR-independent nature of these neurodevelopmental defects was demonstrated by the inability of rapamycin to rescue the GABAergic network defects observed in depdc5-/- brains and, conversely, the inability of GABA to rescue the hypoactivity in another genetic model showing mTOR hyperactivation. This study hence provides the first in vivo evidence that DEPDC5 plays previously unknown roles apart from its canonical function as an mTOR inhibitor. Moreover, these results propose that defective neurodevelopment of GABAergic networks could be a key factor in epileptogenesis when DEPDC5 is mutated.
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Affiliation(s)
- Amrutha Swaminathan
- Department of Neurosciences, Research Center of the University of Montréal Hospital Center (CRCHUM), Université de Montréal, Montréal, QC, Canada H2X 0A9
| | - Rahma Hassan-Abdi
- Inserm, U1141, F-75019 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, UMRS 1141, F-75019 Paris, France
| | - Solène Renault
- Inserm, U1141, F-75019 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, UMRS 1141, F-75019 Paris, France
| | - Aleksandra Siekierska
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, 3000 Leuven, Belgium
| | - Raphaëlle Riché
- Department of Neurosciences, Research Center of the University of Montréal Hospital Center (CRCHUM), Université de Montréal, Montréal, QC, Canada H2X 0A9
| | - Meijiang Liao
- Department of Neurosciences, Research Center of the University of Montréal Hospital Center (CRCHUM), Université de Montréal, Montréal, QC, Canada H2X 0A9
| | - Peter A M de Witte
- Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven, 3000 Leuven, Belgium
| | - Constantin Yanicostas
- Inserm, U1141, F-75019 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, UMRS 1141, F-75019 Paris, France
| | - Nadia Soussi-Yanicostas
- Inserm, U1141, F-75019 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, UMRS 1141, F-75019 Paris, France
| | - Pierre Drapeau
- Department of Neurosciences, Research Center of the University of Montréal Hospital Center (CRCHUM), Université de Montréal, Montréal, QC, Canada H2X 0A9; DanioDesign, Montréal, QC, Canada.
| | - Éric Samarut
- Department of Neurosciences, Research Center of the University of Montréal Hospital Center (CRCHUM), Université de Montréal, Montréal, QC, Canada H2X 0A9; DanioDesign, Montréal, QC, Canada.
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30
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Antonellis A, Oprescu SN, Griffin LB, Heider A, Amalfitano A, Innis JW. Compound heterozygosity for loss-of-function FARSB variants in a patient with classic features of recessive aminoacyl-tRNA synthetase-related disease. Hum Mutat 2018; 39:834-840. [PMID: 29573043 DOI: 10.1002/humu.23424] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/17/2018] [Accepted: 03/10/2018] [Indexed: 12/21/2022]
Abstract
Aminoacyl-tRNA synthetases (ARSs) are ubiquitously expressed enzymes that ligate amino acids onto tRNA molecules. Genes encoding ARSs have been implicated in phenotypically diverse dominant and recessive human diseases. The charging of tRNAPHE with phenylalanine is performed by a tetrameric enzyme that contains two alpha (FARSA) and two beta (FARSB) subunits. To date, mutations in the genes encoding these subunits (FARSA and FARSB) have not been implicated in any human disease. Here, we describe a patient with a severe, lethal, multisystem, developmental phenotype who was compound heterozygous for FARSB variants: p.Thr256Met and p.His496Lysfs*14. Expression studies using fibroblasts isolated from the proband revealed a severe depletion of both FARSB and FARSA protein levels. These data indicate that the FARSB variants destabilize total phenylalanyl-tRNA synthetase levels, thus causing a loss-of-function effect. Importantly, our patient shows strong phenotypic overlap with patients that have recessive diseases associated with other ARS loci; these observations strongly support the pathogenicity of the identified FARSB variants and are consistent with the essential function of phenylalanyl-tRNA synthetase in human cells. In sum, our clinical, genetic, and functional analyses revealed the first FARSB variants associated with a human disease phenotype and expand the locus heterogeneity of ARS-related human disease.
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Affiliation(s)
- Anthony Antonellis
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan.,Department of Neurology, University of Michigan Medical School, Ann Arbor, Michigan.,Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, Michigan
| | - Stephanie N Oprescu
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan
| | - Laurie B Griffin
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, Michigan.,Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, Michigan
| | - Amer Heider
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Andrea Amalfitano
- Department of Pediatrics, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan.,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan
| | - Jeffrey W Innis
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan.,Department of Pediatrics, Division of Genetics, Metabolism, and Genomic Medicine, University of Michigan Medical School, Ann Arbor, Michigan
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31
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Bruni F, Di Meo I, Bellacchio E, Webb BD, McFarland R, Chrzanowska‐Lightowlers ZM, He L, Skorupa E, Moroni I, Ardissone A, Walczak A, Tyynismaa H, Isohanni P, Mandel H, Prokisch H, Haack T, Bonnen PE, Enrico B, Pronicka E, Ghezzi D, Taylor RW, Diodato D. Clinical, biochemical, and genetic features associated with VARS2-related mitochondrial disease. Hum Mutat 2018; 39:563-578. [PMID: 29314548 PMCID: PMC5873438 DOI: 10.1002/humu.23398] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 12/21/2017] [Accepted: 12/28/2017] [Indexed: 01/17/2023]
Abstract
In recent years, an increasing number of mitochondrial disorders have been associated with mutations in mitochondrial aminoacyl‐tRNA synthetases (mt‐aaRSs), which are key enzymes of mitochondrial protein synthesis. Bi‐allelic functional variants in VARS2, encoding the mitochondrial valyl tRNA‐synthetase, were first reported in a patient with psychomotor delay and epilepsia partialis continua associated with an oxidative phosphorylation (OXPHOS) Complex I defect, before being described in a patient with a neonatal form of encephalocardiomyopathy. Here we provide a detailed genetic, clinical, and biochemical description of 13 patients, from nine unrelated families, harboring VARS2 mutations. All patients except one, who manifested with a less severe disease course, presented at birth exhibiting severe encephalomyopathy and cardiomyopathy. Features included hypotonia, psychomotor delay, seizures, feeding difficulty, abnormal cranial MRI, and elevated lactate. The biochemical phenotype comprised a combined Complex I and Complex IV OXPHOS defect in muscle, with patient fibroblasts displaying normal OXPHOS activity. Homology modeling supported the pathogenicity of VARS2 missense variants. The detailed description of this cohort further delineates our understanding of the clinical presentation associated with pathogenic VARS2 variants and we recommend that this gene should be considered in early‐onset mitochondrial encephalomyopathies or encephalocardiomyopathies.
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Affiliation(s)
- Francesco Bruni
- Wellcome Centre for Mitochondrial ResearchInstitute of NeuroscienceNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Ivano Di Meo
- Molecular Neurogenetics UnitFoundation IRCCS Neurological Institute C. BestaMilanItaly
| | - Emanuele Bellacchio
- Genetics and Rare DiseasesResearch Division‘Bambino Gesù’ Children HospitalRomeItaly
| | - Bryn D. Webb
- Department of Genetics and Genomic SciencesIcahn School of Medicine at Mount SinaiNew YorkNew York
| | - Robert McFarland
- Wellcome Centre for Mitochondrial ResearchInstitute of NeuroscienceNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | | | - Langping He
- Wellcome Centre for Mitochondrial ResearchInstitute of NeuroscienceNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Ewa Skorupa
- Department of BiochemistryRadioimmunology and Experimental MedicineThe Children's Memorial Health InstituteWarsawPoland
| | - Isabella Moroni
- Child Neurology UnitFoundation IRCCS Neurological Institute “C. Besta”MilanItaly
| | - Anna Ardissone
- Molecular Neurogenetics UnitFoundation IRCCS Neurological Institute C. BestaMilanItaly
- Child Neurology UnitFoundation IRCCS Neurological Institute “C. Besta”MilanItaly
- Department of Molecular and Translational Medicine DIMETUniversity of Milan‐BicoccaMilanItaly
| | - Anna Walczak
- Department of Medical GeneticsCentre of BiostructureMedical University of WarsawWarsawPoland
| | - Henna Tyynismaa
- Research Programs UnitMolecular NeurologyUniversity of HelsinkiHelsinkiFinland
| | - Pirjo Isohanni
- Research Programs UnitMolecular NeurologyUniversity of HelsinkiHelsinkiFinland
- Department of Pediatric NeurologyChildren's HospitalUniversity of Helsinki and Helsinki University HospitalHelsinkiFinland
| | - Hanna Mandel
- Institute of Human Genetics and Metabolic DiseasesGalilee Medical CenterNahariyaIsrael
| | - Holger Prokisch
- Institute of Human GeneticsTechnische Universität MünchenMunichGermany
- Institute of Human GeneticsHelmholtz Zentrum MünchenNeuherbergGermany
| | - Tobias Haack
- Institute of Human GeneticsHelmholtz Zentrum MünchenNeuherbergGermany
| | - Penelope E. Bonnen
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonTexas
| | - Bertini Enrico
- Unit of Neuromuscular and Neurodegenerative DisordersLaboratory of Molecular Medicine‘Bambino Ges.’ Children's Research HospitalRomeItaly
| | - Ewa Pronicka
- Department of PediatricsNutrition and Metabolic DiseasesThe Children's Memorial Health InstituteWarsawPoland
| | - Daniele Ghezzi
- Molecular Neurogenetics UnitFoundation IRCCS Neurological Institute C. BestaMilanItaly
- Department of Pathophysiology and TransplantationUniversity of MilanMilanItaly
| | - Robert W. Taylor
- Wellcome Centre for Mitochondrial ResearchInstitute of NeuroscienceNewcastle UniversityNewcastle upon TyneUnited Kingdom
| | - Daria Diodato
- Unit of Neuromuscular and Neurodegenerative DisordersLaboratory of Molecular Medicine‘Bambino Ges.’ Children's Research HospitalRomeItaly
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32
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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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33
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Aminoacyl-tRNA synthetases: Structure, function, and drug discovery. Int J Biol Macromol 2018; 111:400-414. [PMID: 29305884 DOI: 10.1016/j.ijbiomac.2017.12.157] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 12/27/2017] [Accepted: 12/29/2017] [Indexed: 01/02/2023]
Abstract
Aminoacyl-tRNA synthetases (AARSs) are the enzymes that catalyze the aminoacylation reaction by covalently linking an amino acid to its cognate tRNA in the first step of protein translation. Beyond this classical function, these enzymes are also known to have a role in several metabolic and signaling pathways that are important for cell viability. Study of these enzymes is of great interest to the researchers due to its pivotal role in the growth and survival of an organism. Further, unfolding the interesting structural and functional aspects of these enzymes in the last few years has qualified them as a potential drug target against various diseases. Here we review the classification, function, and the conserved as well the appended structural architecture of these enzymes in detail, including its association with multi-synthetase complexes. We also considered their role in human diseases in terms of mutations and autoantibodies against AARSs. Finally, we have discussed the available inhibitors against AARSs. This review offers comprehensive information on AARSs under a single canopy that would be a good inventory for researchers working in this area.
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34
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Vantroys E, Larson A, Friederich M, Knight K, Swanson MA, Powell CA, Smet J, Vergult S, De Paepe B, Seneca S, Roeyers H, Menten B, Minczuk M, Vanlander A, Van Hove J, Van Coster R. New insights into the phenotype of FARS2 deficiency. Mol Genet Metab 2017; 122:172-181. [PMID: 29126765 PMCID: PMC5734183 DOI: 10.1016/j.ymgme.2017.10.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/09/2017] [Accepted: 10/10/2017] [Indexed: 12/12/2022]
Abstract
Mutations in FARS2 are known to cause dysfunction of mitochondrial translation due to deficient aminoacylation of the mitochondrial phenylalanine tRNA. Here, we report three novel mutations in FARS2 found in two patients in a compound heterozygous state. The missense mutation c.1082C>T (p.Pro361Leu) was detected in both patients. The mutations c.461C>T (p.Ala154Val) and c.521_523delTGG (p.Val174del) were each detected in one patient. We report abnormal in vitro aminoacylation assays as a functional validation of the molecular genetic findings. Based on the phenotypic data of previously reported subjects and the two subjects reported here, we conclude that FARS2 deficiency can be associated with two phenotypes: (i) an epileptic phenotype, and (ii) a spastic paraplegia phenotype.
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Affiliation(s)
- Elise Vantroys
- Department of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Austin Larson
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, CO, USA
| | - Marisa Friederich
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, CO, USA
| | - Kaz Knight
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, CO, USA
| | - Michael A Swanson
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, CO, USA
| | - Christopher A Powell
- MRC Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Joél Smet
- Department of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Sarah Vergult
- Center for Medical Genetics Ghent, Ghent University, Ghent, Belgium
| | - Boel De Paepe
- Department of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Sara Seneca
- Center for Medical Genetics, UZ Brussel and Reproduction Genetics and Regenerative Medicine, Vrije Universiteit Brussel, Brussels, Belgium
| | - Herbert Roeyers
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium
| | - Björn Menten
- Center for Medical Genetics Ghent, Ghent University, Ghent, Belgium
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Hills Road, Cambridge CB2 0XY, UK
| | - Arnaud Vanlander
- Department of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Johan Van Hove
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, CO, USA
| | - Rudy Van Coster
- Department of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium.
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35
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Wortmann SB, Timal S, Venselaar H, Wintjes LT, Kopajtich R, Feichtinger RG, Onnekink C, Mühlmeister M, Brandt U, Smeitink JA, Veltman JA, Sperl W, Lefeber D, Pruijn G, Stojanovic V, Freisinger P, V Spronsen F, Derks TG, Veenstra-Knol HE, Mayr JA, Rötig A, Tarnopolsky M, Prokisch H, Rodenburg RJ. Biallelic variants in WARS2 encoding mitochondrial tryptophanyl-tRNA synthase in six individuals with mitochondrial encephalopathy. Hum Mutat 2017; 38:1786-1795. [PMID: 28905505 DOI: 10.1002/humu.23340] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 09/07/2017] [Accepted: 09/10/2017] [Indexed: 12/12/2022]
Abstract
Mitochondrial protein synthesis involves an intricate interplay between mitochondrial DNA encoded RNAs and nuclear DNA encoded proteins, such as ribosomal proteins and aminoacyl-tRNA synthases. Eukaryotic cells contain 17 mitochondria-specific aminoacyl-tRNA synthases. WARS2 encodes mitochondrial tryptophanyl-tRNA synthase (mtTrpRS), a homodimeric class Ic enzyme (mitochondrial tryptophan-tRNA ligase; EC 6.1.1.2). Here, we report six individuals from five families presenting with either severe neonatal onset lactic acidosis, encephalomyopathy and early death or a later onset, more attenuated course of disease with predominating intellectual disability. Respiratory chain enzymes were usually normal in muscle and fibroblasts, while a severe combined respiratory chain deficiency was found in the liver of a severely affected individual. Exome sequencing revealed rare biallelic variants in WARS2 in all affected individuals. An increase of uncharged mitochondrial tRNATrp and a decrease of mtTrpRS protein content were found in fibroblasts of affected individuals. We hereby define the clinical, neuroradiological, and metabolic phenotype of WARS2 defects. This confidently implicates that mutations in WARS2 cause mitochondrial disease with a broad spectrum of clinical presentation.
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Affiliation(s)
- Saskia B Wortmann
- Department of Pediatrics, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), Salzburg, Austria.,Institute of Human Genetics, Helmholtz Zentrum Munich, Neuherberg, Germany.,Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Sharita Timal
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Neurology, Donders Center for Brain, Cognition, and Behavior, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hanka Venselaar
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Liesbeth T Wintjes
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Robert Kopajtich
- Institute of Human Genetics, Helmholtz Zentrum Munich, Neuherberg, Germany
| | - René G Feichtinger
- Department of Pediatrics, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), Salzburg, Austria
| | - Carla Onnekink
- Department of Biomolecular Chemistry, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands.,Department of Biomolecular Chemistry, Institute for Molecules and Materials, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mareike Mühlmeister
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ulrich Brandt
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jan A Smeitink
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joris A Veltman
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands.,Institute of Genetic Medicine, International Centre for Life, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Wolfgang Sperl
- Department of Pediatrics, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), Salzburg, Austria
| | - Dirk Lefeber
- Department of Neurology, Donders Center for Brain, Cognition, and Behavior, Translational Metabolic Laboratory, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ger Pruijn
- Department of Biomolecular Chemistry, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands.,Department of Biomolecular Chemistry, Institute for Molecules and Materials, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Vesna Stojanovic
- School of Medicine, University of Novi Sad, Novi Sad, Serbia.,Institute for Child and Youth Health Care of Vojvodina, Intensive Care Unit, Novi Sad, Serbia
| | - Peter Freisinger
- Children's Hospital, Klinikum am Steinenberg, Reutlingen, Germany
| | - Francjan V Spronsen
- Division of Metabolic Diseases, Beatrix Children's Hospital, University of Groningen, University Medical Center of Groningen, Groningen, the Netherlands
| | - Terry Gj Derks
- Division of Metabolic Diseases, Beatrix Children's Hospital, University of Groningen, University Medical Center of Groningen, Groningen, the Netherlands
| | - Hermine E Veenstra-Knol
- Department of Genetics, University of Groningen, University Medical Center of Groningen, Groningen, the Netherlands
| | - Johannes A Mayr
- Department of Pediatrics, Salzburger Landeskliniken (SALK) and Paracelsus Medical University (PMU), Salzburg, Austria
| | - Agnes Rötig
- INSERM U1163, Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, Paris, France
| | - Mark Tarnopolsky
- Department of Pediatrics, Division of Neuromuscular and Neurometabolic Diseases, McMaster University Medical Center, Hamilton, Ontario, Canada
| | - Holger Prokisch
- Institute of Human Genetics, Helmholtz Zentrum Munich, Neuherberg, Germany.,Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Richard J Rodenburg
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
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36
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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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37
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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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38
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Kartvelishvili E, Tworowski D, Vernon H, Moor N, Wang J, Wong LJ, Chrzanowska-Lightowlers Z, Safro M. Kinetic and structural changes in HsmtPheRS, induced by pathogenic mutations in human FARS2. Protein Sci 2017; 26:1505-1516. [PMID: 28419689 PMCID: PMC5521548 DOI: 10.1002/pro.3176] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/11/2017] [Accepted: 04/11/2017] [Indexed: 12/13/2022]
Abstract
Mutations in the mitochondrial aminoacyl-tRNA synthetases (mtaaRSs) can cause profound clinical presentations, and have manifested as diseases with very selective tissue specificity. To date most of the mtaaRS mutations could be phenotypically recognized, such that clinicians could identify the affected mtaaRS from the symptoms alone. Among the recently reported pathogenic variants are point mutations in FARS2 gene, encoding the human mitochondrial PheRS. Patient symptoms range from spastic paraplegia to fatal infantile Alpers encephalopathy. How clinical manifestations of these mutations relate to the changes in three-dimensional structures and kinetic characteristics remains unclear, although impaired aminoacylation has been proposed as possible etiology of diseases. Here, we report four crystal structures of HsmtPheRS mutants, and extensive MD simulations for wild-type and nine mutants to reveal the structural changes on dynamic trajectories of HsmtPheRS. Using steady-state kinetic measurements of phenylalanine activation and tRNAPhe aminoacylation, we gained insight into the structural and kinetic effects of mitochondrial disease-related mutations in FARS2 gene.
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Affiliation(s)
| | - Dmitry Tworowski
- Department of Structural Biology, Weizmann Institute of Science, Israel
| | - Hilary Vernon
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore
| | - Nina Moor
- Laboratory of Bioorganic Chemistry of Enzymes, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | - Jing Wang
- Ambry Genetics, California.,Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Lee-Jun Wong
- Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | | | - Mark Safro
- Department of Structural Biology, Weizmann Institute of Science, Israel
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39
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Cho JS, Kim SH, Kim HY, Chung T, Kim D, Jang S, Lee SB, Yoo SK, Shin J, Kim JI, Kim H, Hwang H, Chae JH, Choi J, Kim KJ, Lim BC. FARS2 mutation and epilepsy: Possible link with early-onset epileptic encephalopathy. Epilepsy Res 2017; 129:118-124. [DOI: 10.1016/j.eplepsyres.2016.11.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 11/23/2016] [Accepted: 11/30/2016] [Indexed: 11/26/2022]
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40
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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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41
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Raviglione F, Conte G, Ghezzi D, Parazzini C, Righini A, Vergaro R, Legati A, Spaccini L, Gasperini S, Garavaglia B, Mastrangelo M. Clinical findings in a patient with FARS2 mutations and early-infantile-encephalopathy with epilepsy. Am J Med Genet A 2016; 170:3004-3007. [PMID: 27549011 DOI: 10.1002/ajmg.a.37836] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 06/26/2016] [Indexed: 12/22/2022]
Abstract
The FARS2 gene encodes the mitochondrial phenylalanyl-tRNA synthetase and is implicated in autosomal recessive combined oxidative phosphorylation deficiency 14, a clinical condition characterized by infantile onset epilepsy and encephalopathy. Mutations in FARS2 have been reported in only few patients, but a detailed description of seizures, electroencephalographic patterns, magnetic resonance imaging findings, and long-term follow-up is still needed. We provide a clinical report of a child with FARS2-related disease manifesting drug-resistant infantile spasms associated with focal seizures. By comparative genomic hybridization analysis we identified a heterozygous microdeletion in the short arm of chromosome 6, inherited from the mother, that encompasses the first coding exon of FARS2. By sequencing of the FARS2 gene we identified a variant c.1156C>G; p.(R386G), inherited from the father. By using standard spectrophotometric techniques in skin fibroblasts, we found a combined abnormality of complexes I and IV of the mitochondrial respiratory chain. The main clinical features of the patient included axial hypotonia, mild distal hypertonia, and psychomotor delay. The magnetic resonance imaging showed microcephaly, frontal cerebral atrophy, and signal changes of dentate nuclei. At the age of 3 years and 6 months, the patient was still under treatment with vigabatrin and he has been seizure free for the last 23 months. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
| | - Giorgio Conte
- Postgraduation School in Radiodiagnostics, Università degli Studi di Milano, Milan, Italy.,Department of Paediatric Radiology and Neuroradiology, Children's Hospital V. Buzzi, Milan, Italy
| | - Daniele Ghezzi
- Molecular Neurogenetics Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Cecilia Parazzini
- Department of Paediatric Radiology and Neuroradiology, Children's Hospital V. Buzzi, Milan, Italy
| | - Andrea Righini
- Department of Paediatric Radiology and Neuroradiology, Children's Hospital V. Buzzi, Milan, Italy
| | - Raffaella Vergaro
- Paediatric Neurology Unit, Children's Hospital V. Buzzi, Milan, Italy
| | - Andrea Legati
- Molecular Neurogenetics Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Luigina Spaccini
- Clinical Genetics Service, Children's Hospital V. Buzzi, Milan, Italy
| | - Serena Gasperini
- Department of Pediatrics, Fondazione MBBM, San Gerardo Hospital, Monza, Italy
| | - Barbara Garavaglia
- Molecular Neurogenetics Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
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42
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Walker MA, Mohler KP, Hopkins KW, Oakley DH, Sweetser DA, Ibba M, Frosch MP, Thibert RL. Novel Compound Heterozygous Mutations Expand the Recognized Phenotypes of FARS2-Linked Disease. J Child Neurol 2016; 31:1127-37. [PMID: 27095821 PMCID: PMC4981184 DOI: 10.1177/0883073816643402] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 03/03/2016] [Indexed: 12/28/2022]
Abstract
Mutations in mitochondrial aminoacyl-tRNA synthetases are an increasingly recognized cause of human diseases, often arising in individuals with compound heterozygous mutations and presenting with system-specific phenotypes, frequently neurologic. FARS2 encodes mitochondrial phenylalanyl transfer ribonucleic acid (RNA) synthetase (mtPheRS), perturbations of which have been reported in 6 cases of an infantile, lethal disease with refractory epilepsy and progressive myoclonus. Here the authors report the case of juvenile onset refractory epilepsy and progressive myoclonus with compound heterozygous FARS2 mutations. The authors describe the clinical course over 6 years of care at their institution and diagnostic studies including electroencephalogram (EEG), brain magnetic resonance imaging (MRI), serum and cerebrospinal fluid analyses, skeletal muscle biopsy histology, and autopsy gross and histologic findings, which include features shared with Alpers-Huttenlocher syndrome, Leigh syndrome, and a previously published case of FARS2 mutation associated infantile onset disease. The authors also present structure-guided analysis of the relevant mutations based on published mitochondrial phenylalanyl transfer RNA synthetase and related protein crystal structures as well as biochemical analysis of the corresponding recombinant mutant proteins.
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Affiliation(s)
- Melissa A Walker
- Division of Child Neurology, Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Kyle P Mohler
- Department of Microbiology, Ohio State University, Columbus, OH, USA
| | - Kyle W Hopkins
- Department of Microbiology, Ohio State University, Columbus, OH, USA
| | - Derek H Oakley
- Division of Neuropathology, Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
| | - David A Sweetser
- Department of Medical Genetics, Massachusetts General Hospital, Boston, MA, USA
| | - Michael Ibba
- Department of Microbiology, Ohio State University, Columbus, OH, USA
| | - Matthew P Frosch
- Division of Neuropathology, Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
| | - Ronald L Thibert
- Department of Neurology, Division of Child Neurology, Massachusetts General Hospital, Boston, MA, USA
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43
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Pathological ribonuclease H1 causes R-loop depletion and aberrant DNA segregation in mitochondria. Proc Natl Acad Sci U S A 2016; 113:E4276-85. [PMID: 27402764 DOI: 10.1073/pnas.1600537113] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The genetic information in mammalian mitochondrial DNA is densely packed; there are no introns and only one sizeable noncoding, or control, region containing key cis-elements for its replication and expression. Many molecules of mitochondrial DNA bear a third strand of DNA, known as "7S DNA," which forms a displacement (D-) loop in the control region. Here we show that many other molecules contain RNA as a third strand. The RNA of these R-loops maps to the control region of the mitochondrial DNA and is complementary to 7S DNA. Ribonuclease H1 is essential for mitochondrial DNA replication; it degrades RNA hybridized to DNA, so the R-loop is a potential substrate. In cells with a pathological variant of ribonuclease H1 associated with mitochondrial disease, R-loops are of low abundance, and there is mitochondrial DNA aggregation. These findings implicate ribonuclease H1 and RNA in the physical segregation of mitochondrial DNA, perturbation of which represents a previously unidentified disease mechanism.
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44
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Linnankivi T, Neupane N, Richter U, Isohanni P, Tyynismaa H. Splicing Defect in Mitochondrial Seryl-tRNA Synthetase Gene Causes Progressive Spastic Paresis Instead of HUPRA Syndrome. Hum Mutat 2016; 37:884-8. [PMID: 27279129 DOI: 10.1002/humu.23021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/23/2016] [Indexed: 01/08/2023]
Abstract
Mitochondrial aminoacyl-tRNA synthetases are an important group of disease genes typically underlying either a disorder affecting an isolated tissue or a distinct syndrome. Missense mutations in the mitochondrial seryl-tRNA synthetase gene, SARS2, have been identified in HUPRA syndrome (hyperuricemia, pulmonary hypertension, renal failure in infancy, and alkalosis). We report here a homozygous splicing mutation in SARS2 in a patient with progressive spastic paresis. We show that the mutation leads to diminished levels of the synthetase in patient's fibroblasts. This has a destabilizing effect on the tRNASer(AGY) isoacceptor, but to a lesser degree than in HUPRA syndrome patients. tRNASer(UCN) is largely unaffected in both phenotypes. In conclusion, the level of tRNASer(AGY) instability may be a factor in determining tissue manifestation in patients with SARS2 mutations. This finding exemplifies the sensitivity of the nervous system to partially reduced aminoacylation, which is sufficient in other tissues to maintain respiratory chain function.
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Affiliation(s)
- Tarja Linnankivi
- Department of Pediatric Neurology, Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Nirajan Neupane
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Uwe Richter
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Pirjo Isohanni
- Department of Pediatric Neurology, Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Henna Tyynismaa
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
- Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland
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45
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Hautakangas MR, Hinttala R, Rantala H, Nieminen P, Uusimaa J, Hassinen IE. Evaluating clinical mitochondrial respiratory chain enzymes from biopsy specimens presenting skewed probability distribution of activity data. Mitochondrion 2016; 29:53-8. [PMID: 27223842 DOI: 10.1016/j.mito.2016.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 04/05/2016] [Accepted: 05/16/2016] [Indexed: 12/13/2022]
Abstract
Due to the relative rarity of mitochondrial diseases, generating reference ranges is problematic in evaluation of respiratory chain activities particularly in pediatric cases. We determined the sample distribution of respiratory chain enzyme activities in skeletal muscle biopsies collected from pediatric patients suspected of neuromuscular disorders. Activities of NADH-ubiquinone reductase, NADH-cytochrome c reductase, succinate-cytochrome c reductase; ubiquinol-cytochrome c reductase and cytochrome c oxidase activities have log-normal distributions even when confirmed mitochondrial diseases were ruled out. Impact of the log-normal distribution of the respiratory chain enzyme activities on clinical diagnostics is discussed.
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Affiliation(s)
- Milla-Riikka Hautakangas
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, Finland; Department of Children and Adolescents, Division of Pediatric Neurology, Oulu University Hospital, Finland.
| | - Reetta Hinttala
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, Finland; Department of Children and Adolescents, Division of Pediatric Neurology, Oulu University Hospital, Finland.
| | - Heikki Rantala
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, Finland; Department of Children and Adolescents, Division of Pediatric Neurology, Oulu University Hospital, Finland.
| | - Pentti Nieminen
- Medical Informatics and Statistics Group, University of Oulu, Finland.
| | - Johanna Uusimaa
- PEDEGO Research Unit and Medical Research Center Oulu, University of Oulu, Finland; Department of Children and Adolescents, Division of Pediatric Neurology, Oulu University Hospital, Finland.
| | - Ilmo E Hassinen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.
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46
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Metodiev M, Thompson K, Alston C, Morris A, He L, Assouline Z, Rio M, Bahi-Buisson N, Pyle A, Griffin H, Siira S, Filipovska A, Munnich A, Chinnery P, McFarland R, Rötig A, Taylor R. Recessive Mutations in TRMT10C Cause Defects in Mitochondrial RNA Processing and Multiple Respiratory Chain Deficiencies. Am J Hum Genet 2016; 98:993-1000. [PMID: 27132592 PMCID: PMC4863561 DOI: 10.1016/j.ajhg.2016.03.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/14/2016] [Indexed: 12/31/2022] Open
Abstract
Mitochondrial disorders are clinically and genetically diverse, with mutations in mitochondrial or nuclear genes able to cause defects in mitochondrial gene expression. Recently, mutations in several genes encoding factors involved in mt-tRNA processing have been identified to cause mitochondrial disease. Using whole-exome sequencing, we identified mutations in TRMT10C (encoding the mitochondrial RNase P protein 1 [MRPP1]) in two unrelated individuals who presented at birth with lactic acidosis, hypotonia, feeding difficulties, and deafness. Both individuals died at 5 months after respiratory failure. MRPP1, along with MRPP2 and MRPP3, form the mitochondrial ribonuclease P (mt-RNase P) complex that cleaves the 5′ ends of mt-tRNAs from polycistronic precursor transcripts. Additionally, a stable complex of MRPP1 and MRPP2 has m1R9 methyltransferase activity, which methylates mt-tRNAs at position 9 and is vital for folding mt-tRNAs into their correct tertiary structures. Analyses of fibroblasts from affected individuals harboring TRMT10C missense variants revealed decreased protein levels of MRPP1 and an increase in mt-RNA precursors indicative of impaired mt-RNA processing and defective mitochondrial protein synthesis. The pathogenicity of the detected variants—compound heterozygous c.542G>T (p.Arg181Leu) and c.814A>G (p.Thr272Ala) changes in subject 1 and a homozygous c.542G>T (p.Arg181Leu) variant in subject 2—was validated by the functional rescue of mt-RNA processing and mitochondrial protein synthesis defects after lentiviral transduction of wild-type TRMT10C. Our study suggests that these variants affect MRPP1 protein stability and mt-tRNA processing without affecting m1R9 methyltransferase activity, identifying mutations in TRMT10C as a cause of mitochondrial disease and highlighting the importance of RNA processing for correct mitochondrial function.
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47
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Yang Y, Liu W, Fang Z, Shi J, Che F, He C, Yao L, Wang E, Wu Y. A Newly Identified Missense Mutation in FARS2 Causes Autosomal-Recessive Spastic Paraplegia. Hum Mutat 2015; 37:165-9. [PMID: 26553276 DOI: 10.1002/humu.22930] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 11/03/2015] [Indexed: 02/05/2023]
Abstract
Hereditary spastic paraplegia (HSP) is a clinically and genetically heterogeneous group of neurodegenerative disorders characterized by spasticity of the lower limbs due to pyramidal tract dysfunction. Here, we report that a missense homozygous mutation c.424G>T (p.D142Y) in the FARS2 gene, which encodes a mitochondrial phenylalanyl tRNA synthetase (mtPheRS), causes HSP in a Chinese consanguineous family by using combination of homozygous mapping and whole-exome sequencing. Immunohistochemical experiments were performed showing that the FARS2 protein was highly expressed in the Purkinje cells of rat cerebellum. The aminoacylation activity of mtPheRS was severely disrupted by the p.D142Y substitution in vitro not only in the first aminoacylation step but also in the last transfer step. Taken together, our results indicate that a missense mutation in FARS2 contributes to HSP, which has the clinical significance of the regulation of tRNA synthetases in human neurodegenerative diseases.
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Affiliation(s)
- Ying Yang
- Department of Biochemistry and Molecular Biology, Xi'an, Shaanxi, 710032, China.,Center for DNA Typing, Xi'an, Shaanxi, 710032, China
| | - Wei Liu
- Department of physiotherapy, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, 710032, China
| | - Zhipeng Fang
- Center for RNA Research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai, 710031, China
| | - Juan Shi
- Department of Anatomy, Histology and Embryology & K.K. Leung Brain Research Centre, Preclinical School of Medicine, Fourth Military Medical University, Xi'an, Shaanxi, 200032, China
| | - Fengyu Che
- Center for DNA Typing, Xi'an, Shaanxi, 710032, China
| | - Chunxia He
- Department of Biochemistry and Molecular Biology, Xi'an, Shaanxi, 710032, China.,Center for DNA Typing, Xi'an, Shaanxi, 710032, China
| | - Libo Yao
- Department of Biochemistry and Molecular Biology, Xi'an, Shaanxi, 710032, China
| | - Enduo Wang
- Center for RNA Research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai, 710031, China
| | - Yuanming Wu
- Department of Biochemistry and Molecular Biology, Xi'an, Shaanxi, 710032, China.,Center for DNA Typing, Xi'an, Shaanxi, 710032, China
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48
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Vanlander AV, Menten B, Smet J, De Meirleir L, Sante T, De Paepe B, Seneca S, Pearce SF, Powell CA, Vergult S, Michotte A, De Latter E, Vantomme L, Minczuk M, Van Coster R. Two siblings with homozygous pathogenic splice-site variant in mitochondrial asparaginyl-tRNA synthetase (NARS2). Hum Mutat 2015; 36:222-31. [PMID: 25385316 DOI: 10.1002/humu.22728] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 10/28/2014] [Indexed: 12/13/2022]
Abstract
A homozygous missense mutation (c.822G>C) was found in the gene encoding the mitochondrial asparaginyl-tRNA synthetase (NARS2) in two siblings born to consanguineous parents. These siblings presented with different phenotypes: one had mild intellectual disability and epilepsy in childhood, whereas the other had severe myopathy. Biochemical analysis of the oxidative phosphorylation (OXPHOS) complexes in both siblings revealed a combined complex I and IV deficiency in skeletal muscle. In-gel activity staining after blue native-polyacrylamide gel electrophoresis confirmed the decreased activity of complex I and IV, and, in addition, showed the presence of complex V subcomplexes. Considering the consanguineous descent, homozygosity mapping and whole-exome sequencing were combined revealing the presence of one single missense mutation in the shared homozygous region. The c.822G>C variant affects the 3' splice site of exon 7, leading to skipping of the whole exon 7 and a part of exon 8 in the NARS2 mRNA. In EBV-transformed lymphoblasts, a specific decrease in the amount of charged mt-tRNA(Asn) was demonstrated as compared with controls. This confirmed the pathogenic nature of the variant. To conclude, the reported variant in NARS2 results in a combined OXPHOS complex deficiency involving complex I and IV, making NARS2 a new member of disease-associated aaRS2.
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Affiliation(s)
- Arnaud V Vanlander
- Department of Pediatric Neurology and Metabolism, Ghent University Hospital, Belgium
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49
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Simons C, Griffin LB, Helman G, Golas G, Pizzino A, Bloom M, Murphy JLP, Crawford J, Evans SH, Topper S, Whitehead MT, Schreiber JM, Chapman KA, Tifft C, Lu KB, Gamper H, Shigematsu M, Taft RJ, Antonellis A, Hou YM, Vanderver A. Loss-of-function alanyl-tRNA synthetase mutations cause an autosomal-recessive early-onset epileptic encephalopathy with persistent myelination defect. Am J Hum Genet 2015; 96:675-81. [PMID: 25817015 DOI: 10.1016/j.ajhg.2015.02.012] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 02/19/2015] [Indexed: 11/30/2022] Open
Abstract
Mutations in genes encoding aminoacyl-tRNA synthetases are known to cause leukodystrophies and genetic leukoencephalopathies-heritable disorders that result in white matter abnormalities in the central nervous system. Here we report three individuals (two siblings and an unrelated individual) with severe infantile epileptic encephalopathy, clubfoot, absent deep tendon reflexes, extrapyramidal symptoms, and persistently deficient myelination on MRI. Analysis by whole exome sequencing identified mutations in the nuclear-encoded alanyl-tRNA synthetase (AARS) in these two unrelated families: the two affected siblings are compound heterozygous for p.Lys81Thr and p.Arg751Gly AARS, and the single affected child is homozygous for p.Arg751Gly AARS. The two identified mutations were found to result in a significant reduction in function. Mutations in AARS were previously associated with an autosomal-dominant inherited form of axonal neuropathy, Charcot-Marie-Tooth disease type 2N (CMT2N). The autosomal-recessive AARS mutations identified in the individuals described here, however, cause a severe infantile epileptic encephalopathy with a central myelin defect and peripheral neuropathy, demonstrating that defects of alanyl-tRNA charging can result in a wide spectrum of disease manifestations.
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Affiliation(s)
- Cas Simons
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Laurie B Griffin
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Guy Helman
- Department of Neurology, Children's National Health System, Washington, DC 20010, USA
| | - Gretchen Golas
- Undiagnosed Diseases Program, NIH, National Human Genome Research Institute, Bethesda, MD 20894, USA
| | - Amy Pizzino
- Department of Neurology, Children's National Health System, Washington, DC 20010, USA
| | - Miriam Bloom
- Department of Hospitalist Medicine, Children's National Health System, Washington, DC 20010, USA
| | - Jennifer L P Murphy
- Department of Neurology, Children's National Health System, Washington, DC 20010, USA
| | - Joanna Crawford
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Sarah H Evans
- Department of Physical Medicine and Rehabilitation, Children's National Health System, Washington, DC 20010, USA
| | | | - Matthew T Whitehead
- Department of Neuroradiology, Children's National Health System, Washington, DC 20010, USA
| | - John M Schreiber
- Department of Neurology, Children's National Health System, Washington, DC 20010, USA
| | - Kimberly A Chapman
- Department of Genetics, Children's National Health System, Washington, DC 20010, USA; Center for Genetic Medicine Research, Children's National Health System, Washington, DC 20010, USA
| | - Cyndi Tifft
- Undiagnosed Diseases Program, NIH, National Human Genome Research Institute, Bethesda, MD 20894, USA
| | - Katrina B Lu
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Howard Gamper
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Megumi Shigematsu
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Ryan J Taft
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; Illumina, Inc., San Diego, CA 92122, USA; Departments of Integrated Systems Biology and of Pediatrics, George Washington University, Washington, DC 20052, USA
| | - Anthony Antonellis
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; 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
| | - Ya-Ming Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Adeline Vanderver
- Medical Scientist Training Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Center for Genetic Medicine Research, Children's National Health System, Washington, DC 20010, USA; Departments of Integrated Systems Biology and of Pediatrics, George Washington University, Washington, DC 20052, USA.
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50
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Simon M, Richard EM, Wang X, Shahzad M, Huang VH, Qaiser TA, Potluri P, Mahl SE, Davila A, Nazli S, Hancock S, Yu M, Gargus J, Chang R, Al-sheqaih N, Newman WG, Abdenur J, Starr A, Hegde R, Dorn T, Busch A, Park E, Wu J, Schwenzer H, Flierl A, Florentz C, Sissler M, Khan SN, Li R, Guan MX, Friedman TB, Wu DK, Procaccio V, Riazuddin S, Wallace DC, Ahmed ZM, Huang T, Riazuddin S. Mutations of human NARS2, encoding the mitochondrial asparaginyl-tRNA synthetase, cause nonsyndromic deafness and Leigh syndrome. PLoS Genet 2015; 11:e1005097. [PMID: 25807530 PMCID: PMC4373692 DOI: 10.1371/journal.pgen.1005097] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 02/23/2015] [Indexed: 12/31/2022] Open
Abstract
Here we demonstrate association of variants in the mitochondrial asparaginyl-tRNA synthetase NARS2 with human hearing loss and Leigh syndrome. A homozygous missense mutation ([c.637G>T; p.Val213Phe]) is the underlying cause of nonsyndromic hearing loss (DFNB94) and compound heterozygous mutations ([c.969T>A; p.Tyr323*] + [c.1142A>G; p.Asn381Ser]) result in mitochondrial respiratory chain deficiency and Leigh syndrome, which is a neurodegenerative disease characterized by symmetric, bilateral lesions in the basal ganglia, thalamus, and brain stem. The severity of the genetic lesions and their effects on NARS2 protein structure cosegregate with the phenotype. A hypothetical truncated NARS2 protein, secondary to the Leigh syndrome mutation p.Tyr323* is not detectable and p.Asn381Ser further decreases NARS2 protein levels in patient fibroblasts. p.Asn381Ser also disrupts dimerization of NARS2, while the hearing loss p.Val213Phe variant has no effect on NARS2 oligomerization. Additionally we demonstrate decreased steady-state levels of mt-tRNAAsn in fibroblasts from the Leigh syndrome patients. In these cells we show that a decrease in oxygen consumption rates (OCR) and electron transport chain (ETC) activity can be rescued by overexpression of wild type NARS2. However, overexpression of the hearing loss associated p.Val213Phe mutant protein in these fibroblasts cannot complement the OCR and ETC defects. Our findings establish lesions in NARS2 as a new cause for nonsyndromic hearing loss and Leigh syndrome. Mitochondrial respiratory chain (MRC) disease represents a large and heterogeneous group of energy deficiency disorders. Here we report three mutations in NARS2, a mitochondrial asparaginyl-tRNA synthetase, associated with non-syndromic hearing loss (NSHL) and Leigh syndrome in two independent families. Located in the predicted catalytic domain of the protein, missense mutation p.(Val213Phe) results in NSHL (DFNB94) while compound heterozygous mutation (p.Tyr323*; p.Asn381Ser) is leading to Leigh syndrome with auditory neuropathy. In vivo analysis deemed p.Tyr323* mutant protein to be unstable. Co-immunoprecipitation assays show that p.Asn381Ser mutant disrupts the dimerization ability of NARS2. Leigh syndrome patient fibroblasts exhibit a decreased steady-state level of mt-tRNAAsn. In addition, in these cells, the mitochondrial respiratory chain is deficient, including significantly decreased oxygen consumption rates and electron transport chain activities. These functions can be partially restored with over-expression of wild-type NARS2 but not with p.Val213Phe mutant protein. Our study provides new insights into the genes that are necessary for the function of brain and inner ear sensory cells in humans.
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Affiliation(s)
- Mariella Simon
- Department of Developmental and Cellular Biology, School of Biological Sciences, University of California, Irvine, Irvine, California, United States of America
- CHOC Childrens’, Division of Metabolics, Orange, California, United States of America
| | - Elodie M. Richard
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Xinjian Wang
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Mohsin Shahzad
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Vincent H. Huang
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Tanveer A. Qaiser
- National Center for Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Prasanth Potluri
- Center for Mitochondrial and Epigenomic Medicine, Children’s Hospital of Philadelphia and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Sarah E. Mahl
- Division of Pediatric Otolaryngology Head & Neck Surgery, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Antonio Davila
- Smilow Center for Translational Research, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Sabiha Nazli
- National Center for Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Saege Hancock
- Trovagene, San Diego, California, United States of America
| | - Margret Yu
- Marshall B Ketchum University, Fullerton, California, United States of America
| | - Jay Gargus
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, California, United States of America
| | - Richard Chang
- CHOC Childrens’, Division of Metabolics, Orange, California, United States of America
| | - Nada Al-sheqaih
- Manchester Centre for Genomic Medicine, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre (MAHSC), Manchester, United Kingdom
| | - William G. Newman
- Manchester Centre for Genomic Medicine, University of Manchester and Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre (MAHSC), Manchester, United Kingdom
| | - Jose Abdenur
- CHOC Childrens’, Division of Metabolics, Orange, California, United States of America
| | - Arnold Starr
- Department of Neurology and Neurobiology, University of California, Irvine, Irvine, California, United States of America
| | - Rashmi Hegde
- Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | | | - Anke Busch
- Institute of Molecular Biology, Mainz, Germany
| | - Eddie Park
- Department of Developmental and Cellular Biology, School of Biological Sciences, University of California, Irvine, Irvine, California, United States of America
| | - Jie Wu
- Institute for Genomics and Bioinformatics, University of California, Irvine, Irvine, California, United States of America
| | - Hagen Schwenzer
- Architecture et Réactivité de l’ARN, CNRS, University of Strasbourg, IBMC, Strasbourg, France
| | - Adrian Flierl
- Parkinson’s Institute and Clinical Center, Sunnyvale, California, United States of America
| | - Catherine Florentz
- Architecture et Réactivité de l’ARN, CNRS, University of Strasbourg, IBMC, Strasbourg, France
| | - Marie Sissler
- Architecture et Réactivité de l’ARN, CNRS, University of Strasbourg, IBMC, Strasbourg, France
| | - Shaheen N. Khan
- National Center for Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Ronghua Li
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Min-Xin Guan
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Thomas B. Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Doris K. Wu
- Section on Sensory Cell Regeneration and Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Vincent Procaccio
- Biochemistry and Genetics Department, UMR CNRS 6214–INSERM U1083, CHU Angers, Angers, France
| | - Sheikh Riazuddin
- Jinnah Hospital Complex, Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan
- University of Lahore, Lahore, Pakistan
- Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Douglas C. Wallace
- Center for Mitochondrial and Epigenomic Medicine, Children’s Hospital of Philadelphia and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Zubair M. Ahmed
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Taosheng Huang
- Division of Human Genetics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- * E-mail: (TH); (SR)
| | - Saima Riazuddin
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
- * E-mail: (TH); (SR)
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