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Xu S, Yang N. The Role and Research Progress of Mitochondria in Sensorineural Hearing Loss. Mol Neurobiol 2024:10.1007/s12035-024-04470-4. [PMID: 39292339 DOI: 10.1007/s12035-024-04470-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 08/30/2024] [Indexed: 09/19/2024]
Abstract
Hearing loss is one of the most common human diseases, seriously affecting everyday lives. Mitochondria, as the energy metabolism center in cells, are also involved in regulating active oxygen metabolism and mediating the occurrence of inflammation and apoptosis. Mitochondrial defects are closely related to hearing diseases. Studies have shown that mitochondrial DNA mutations are one of the causes of hereditary hearing loss. In addition, changes in mitochondrial homeostasis are directly related to noise-induced hearing loss and presbycusis. This review mainly summarizes and discusses the effects of mitochondrial dysfunction and mitophagy on hearing loss. Subsequently, we introduce the recent research progress of targeted mitochondria therapy in the hearing system.
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Affiliation(s)
- Shan Xu
- Department of Otolaryngology, The First Hospital of China Medical University, Shenyang, 110001, China
| | - Ning Yang
- Department of Otolaryngology, The First Hospital of China Medical University, Shenyang, 110001, China.
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Chen X, Meng F, Chen C, Li S, Chou Z, Xu B, Mo JQ, Guo Y, Guan MX. Deafness-associated tRNA Phe mutation impaired mitochondrial and cellular integrity. J Biol Chem 2024; 300:107235. [PMID: 38552739 PMCID: PMC11046301 DOI: 10.1016/j.jbc.2024.107235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 03/06/2024] [Accepted: 03/18/2024] [Indexed: 04/23/2024] Open
Abstract
Defects in mitochondrial RNA metabolism have been linked to sensorineural deafness that often occurs as a consequence of damaged or deficient inner ear hair cells. In this report, we investigated the molecular mechanism underlying a deafness-associated tRNAPhe 593T > C mutation that changed a highly conserved uracil to cytosine at position 17 of the DHU-loop. The m.593T > C mutation altered tRNAPhe structure and function, including increased melting temperature, resistance to S1 nuclease-mediated digestion, and conformational changes. The aberrant tRNA metabolism impaired mitochondrial translation, which was especially pronounced by decreases in levels of ND1, ND5, CYTB, CO1, and CO3 harboring higher numbers of phenylalanine. These alterations resulted in aberrant assembly, instability, and reduced activities of respiratory chain enzyme complexes I, III, IV, and intact supercomplexes overall. Furthermore, we found that the m.593T > C mutation caused markedly diminished membrane potential, and increased the production of reactive oxygen species in the mutant cell lines carrying the m.593T > C mutation. These mitochondrial dysfunctions led to the mitochondrial dynamic imbalance via increasing fission with abnormal mitochondrial morphology. Excessive fission impaired the process of autophagy including the initiation phase, formation, and maturation of the autophagosome. In particular, the m.593T > C mutation upregulated the PARKIN-dependent mitophagy pathway. These alterations promoted an intrinsic apoptotic process for the removal of damaged cells. Our findings provide critical insights into the pathophysiology of maternally inherited deafness arising from tRNA mutation-induced defects in mitochondrial and cellular integrity.
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Affiliation(s)
- Xiaowan Chen
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University First Hospital, Lanzhou, Gansu, China; Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, Zhejiang, China
| | - Feilong Meng
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, Zhejiang, China; Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Chao Chen
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, Zhejiang, China; Center for Mitochondrial Biomedicine, The Fourth Affiliated Hospital Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Shujuan Li
- Department of Otolaryngology-Head and Neck Surgery, Gansu Provincial Hospital, Lanzhou, Gansu, China
| | - Zhiqiang Chou
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University First Hospital, Lanzhou, Gansu, China
| | - Baicheng Xu
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, Lanzhou, Gansu, China
| | - Jun Q Mo
- Department of Pathology, Rady Children's Hospital, University of California School of Medicine, San Diego, California, USA
| | - Yufen Guo
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, Lanzhou, Gansu, China
| | - Min-Xin Guan
- Institute of Genetics, Zhejiang University International School of Medicine, Hangzhou, Zhejiang, China; Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Center for Mitochondrial Biomedicine, The Fourth Affiliated Hospital Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Zhejiang Provincial Lab of Genetics and Genomics, Zhejiang University, Hangzhou, Zhejiang, China.
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Zhang T, Su R, Xiang W, Wang W. Maternally inherited non-syndromic hearing loss is linked with a novel mitochondrial ND6 gene mutation. Ir J Med Sci 2024; 193:937-943. [PMID: 37561388 DOI: 10.1007/s11845-023-03484-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 07/26/2023] [Indexed: 08/11/2023]
Abstract
BACKGROUND Maternally inherited non-syndromic hearing loss is linked with mitochondrial DNA mutations. AIM This investigation demonstrates the features of a Chinese pedigree suffering from maternally inherited non-syndromic hearing loss. METHODS Biochemical characterizations included the measurements ofprotein synthesis levels, membrane potential, and the synthesis of reactive oxygen species (ROS) and adenosine triphosphate (ATP) using cybrid cell lines derived from an affected matrilineal subject and control subject. RESULTS Non-congenital early or late-onset/development hearing impairment has been observed in 4 of 9 in a family (matrilineal), with different degrees of hearing impairment, ranging from normal to severe. A pedigree's whole mitochondrial genome sequence analysis revealed the homoplasmic m.14502 T > C (I58V) mutation at ND6's isoleucine location-58, and specific mitocchondrial DNA polymorphisms set haplogroups M10 were highly conserved. In vitro models indicated that m.14502 T > C mutation-derived respiratory deficiency decreases ND6 protein synthesis, mitochondrial membrane potential, and ATP synthesis. These mitochondrial dysregulations enhance the generation of ROS in the mutant cells. Identifying nuclear modifiers is essential for elucidating hearing loss's pathogenesis and furnishing novel therapeutic interventions. CONCLUSIONS The m.14502 T > C mutation should be considered an inherited risk factor that can help diagnose. The data of this investigation help counsel families of individuals with hearing loss.
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Affiliation(s)
- Ting Zhang
- Department of Clinical Laboratory, The Affiliated Wenling Hospital, Wenzhou Medical University, Wenling, 317500, Zhejiang, China
| | - Renjie Su
- ENT Department, The First People's Hospital of Wenling, Taizhou University, Taizhou, China
- ENT Department, The Affiliated Wenling Hospital of Wenzhou Medical University, Taizhou, China
| | - Wen Xiang
- ENT Department, The First People's Hospital of Wenling, Taizhou University, Taizhou, China
- ENT Department, The Affiliated Wenling Hospital of Wenzhou Medical University, Taizhou, China
| | - Wenbin Wang
- ENT Department, The First People's Hospital of Wenling, Taizhou University, Taizhou, China.
- ENT Department, The Affiliated Wenling Hospital of Wenzhou Medical University, Taizhou, China.
- The First People's Hospital of Wenling, Taizhou University, 333 Chuanannan Road, Taizhou, 317500, China.
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Zhang D, Wu J, Yuan Y, Li X, Gao X, Kang D, Zhang X, Huang SS, Dai P. Mitochondrial tRNA Ser(UCN) mutations associated non-syndromic sensorineural hearing loss in Chinese families. Heliyon 2024; 10:e27041. [PMID: 38501023 PMCID: PMC10945119 DOI: 10.1016/j.heliyon.2024.e27041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 12/29/2023] [Accepted: 02/22/2024] [Indexed: 03/20/2024] Open
Abstract
Mitochondrial transfer RNA mutation is one of the most important causes of hereditary hearing loss in humans. Mitochondrial transfer RNASer (UCN) gene is another hot spot for mutations associated with non-syndromic hearing loss, besides the 12S ribosomal RNA gene. In this study, we assessed the clinical phenotype and the molecular characteristics of two Chinese families with non-syndromic hearing loss. Mutational analysis revealed that 7445A > G and 7510T > C mutations in the mitochondrial transfer RNASer (UCN) gene were the molecular etiology of Family 1 and Family 2, respectively. However, the clinical and genetic characteristics of the two families carrying the above mutations in the transfer RNASer (UCN) gene exhibited a variable expression of hearing loss and an incomplete penetrance. Sequencing analysis of the complete mitochondrial genome showed the presence of transfer RNATrp 5568A > G and NADH-ubiquinone oxidoreductase chain 4 11696G > A mutations in Family 1. The mitochondrial haplotype analysis showed that the two families belonged to Asian D4 and M80'D haplotypes, respectively, and no pathogenic variations were found in the nuclear genes. To our knowledge, our study is the first to report 7445A > G and 7510T > C mutations in the mitochondrial transfer RNASer (UCN) gene, in multi-generation non-syndromic hearing loss pedigrees from China. Our study suggests that 5568A > G and 11696G > A mutations may enhance the penetrance of hearing loss in Chinese Family 1, while mitochondrial haplotypes and known nuclear genes may not be modifiers for the phenotypic expression of 7445A > G and 7510T > C mutations in these Chinese families.
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Affiliation(s)
- Dejun Zhang
- Department of Otolaryngology Head and Neck Surgery, The Second Hospital of Jilin University, Changchun, China
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
| | - Jie Wu
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
| | - Yongyi Yuan
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
| | - Xiaohong Li
- Department of Otolaryngology, Head and Neck Surgery, National Children's Medical Center/Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Xue Gao
- Department of Otolaryngology, PLA Rocket Force Characteristic Medical Center, Beijing, China
| | - Dongyang Kang
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
| | - Xin Zhang
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
| | - Sha-sha Huang
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
| | - Pu Dai
- ColIege of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Beijing, China
- State Key Lab of Hearing Science, Ministry of Education, National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Beijing Key Lab of Hearing Impairment for Prevention and Treatment, Beijing, China
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Yu X, Li S, Guo Q, Leng J, Ding Y. The Association Between Mitochondrial tRNA Glu Variants and Hearing Loss: A Case-Control Study. Pharmgenomics Pers Med 2024; 17:77-89. [PMID: 38562431 PMCID: PMC10984097 DOI: 10.2147/pgpm.s441281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 03/16/2024] [Indexed: 04/04/2024] Open
Abstract
Purpose This study aimed to examine the frequencies of mt-tRNAGlu variants in 180 pediatric patients with non-syndromic hearing loss (NSHL) and 100 controls. Methods Sanger sequencing was performed to screen for mt-tRNAGlu variants. These mitochondrial DNA (mtDNA) pathogenic mutations were further assessed using phylogenetic conservation and haplogroup analyses. We also traced the origins of the family history of probands carrying potential pathogenic mtDNA mutations. Mitochondrial functions including mtDNA content, ATP and reactive oxygen species (ROS) were examined in cells derived from patients carrying the mt-tRNAGlu A14692G and CO1/tRNASer(UCN) G7444A variants and controls. Results We identified four possible pathogenic variants: m.T14709C, m.A14683G, m.A14692G and m.A14693G, which were found in NSHL patients but not in controls. Genetic counseling suggested that one child with the m.A14692G variant had a family history of NSHL. Sequence analysis of mtDNA suggested the presence of the CO1/tRNASer(UCN) G7444A and mt-tRNAGlu A14692G variants. Molecular analysis suggested that, compared with the controls, patients with these variants exhibited much lower mtDNA copy numbers, ATP production, whereas ROS levels increased (p<0.05 for all), suggesting that the m.A14692G and m.G7444A variants led to mitochondrial dysfunction. Conclusion mt-tRNAGlu variants are important risk factors for NSHL.
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Affiliation(s)
- Xuejiao Yu
- Department of Clinical Laboratory, Quzhou People’s Hospital, the Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou, Zhejiang Province, 324000, People’s Republic of China
| | - Sheng Li
- Department of Otolaryngology, Quzhou People’s Hospital, the Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou, Zhejiang Province, 324000, People’s Republic of China
| | - Qinxian Guo
- Central Laboratory, Hangzhou First People’s Hospital, Hangzhou, Zhejiang Province, 310006, People’s Republic of China
| | - Jianhang Leng
- Central Laboratory, Hangzhou First People’s Hospital, Hangzhou, Zhejiang Province, 310006, People’s Republic of China
| | - Yu Ding
- Central Laboratory, Hangzhou First People’s Hospital, Hangzhou, Zhejiang Province, 310006, People’s Republic of China
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Ren B, Guan MX, Zhou T, Cai X, Shan G. Emerging functions of mitochondria-encoded noncoding RNAs. Trends Genet 2023; 39:125-139. [PMID: 36137834 DOI: 10.1016/j.tig.2022.08.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/03/2022] [Accepted: 08/11/2022] [Indexed: 01/27/2023]
Abstract
Mitochondria, organelles that harbor their own circular genomes, are critical for energy production and homeostasis maintenance in eukaryotic cells. Recent studies discovered hundreds of mitochondria-encoded noncoding RNAs (mt-ncRNAs), including novel subtypes of mitochondria-encoded circular RNAs (mecciRNAs) and mitochondria-encoded double-stranded RNAs (mt-dsRNAs). Here, we discuss the emerging field of mt-ncRNAs by reviewing their expression patterns, biogenesis, metabolism, regulatory roles, and functional mechanisms. Many mt-ncRNAs have regulatory roles in cellular physiology, and some are associated with, or even act as, causal factors in human diseases. We also highlight developments in technologies and methodologies and further insights into future perspectives and challenges in studying these noncoding RNAs, as well as their potential biomedical applications.
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Affiliation(s)
- Bingbing Ren
- Department of Pulmonary and Critical Care Medicine, Regional Medical Center for National Institute of Respiratory Disease, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China; Cancer Center, Zhejiang University, Hangzhou 310058, China; Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, The Children's Hospital, School of Medicine, Zhejiang University, Hangzhou 310052, China; Zhejiang Provincial Key Lab of Genetic and Developmental Disorder, Institute of Genetics, School of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Tianhua Zhou
- Cancer Center, Zhejiang University, Hangzhou 310058, China; Department of Cell Biology and Department of Gastroenterology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China; Institute of Gastroenterology, Zhejiang University, Hangzhou 310016, China
| | - Xiujun Cai
- Cancer Center, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Laparoscopic Technology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China; Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China; Zhejiang Minimal Invasive Diagnosis and Treatment Technology Research Center of Severe Hepatobiliary Disease, Zhejiang University, Hangzhou 310016, China; Zhejiang Research and Development Engineering Laboratory of Minimally Invasive Technology and Equipment, Zhejiang University, Hangzhou 310016, China
| | - Ge Shan
- Department of Pulmonary and Critical Care Medicine, Regional Medical Center for National Institute of Respiratory Disease, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China; Cancer Center, Zhejiang University, Hangzhou 310058, China; Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China; Department of Clinical Laboratory, The First Affiliated Hospital of USTC, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Science and Medicine, University of Science and Technology of China, Hefei 230027, China.
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Ji Y, Zhang J, Liang M, Meng F, Zhang M, Mo JQ, Wang M, Guan MX. Mitochondrial tRNA variants in 811 Chinese probands with Leber's hereditary optic neuropathy. Mitochondrion 2022; 65:56-66. [PMID: 35623556 DOI: 10.1016/j.mito.2022.05.003] [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: 03/08/2022] [Revised: 04/26/2022] [Accepted: 05/22/2022] [Indexed: 11/27/2022]
Abstract
Leber's hereditary optic neuropathy (LHON) is the maternal inheritance of eye disorder. LHON-linked mitochondrial DNA (mtDNA) mutations affect the ND1, ND4 or ND6 genes encoding essential subunits of complex I. However, the role of mitochondrial tRNA defects in the pathogenesis of LHON is poorly understood. In this report, Sanger sequence analysis of 22 mitochondrial tRNA genes identified 139 variants in a cohort of 811 Han Chinese probands and 485 control Chinese subjects. Among these, 32 (4 known and 28 novel/putative) tRNA variants in 69 probands may contribute to pathogenesis of LHON, as these exhibited (1) present in <1% of controls; (2) evolutionary conservation; (3) potential and significance of structural and functional modifications. Such variants may have potentially compromised structural and functional aspects in the processing of tRNAs, structure stability, tRNA charging, or codon-anticodon interactions during translation. These 32 variants presented either singly or with multiple mutations, with the primary LHON-linked ND1 3640G>A, ND4 11778G>A or ND6 14484T>C mutations in the probands. The thirty-eight pedigrees carrying only one of tRNA variants exhibited relatively low penetrances of LHON, ranging from 5.7% to 42.9%, with an average of 19%. Strikingly, the average penetrances of optic neuropathy among 33 Chinese families carrying both a known/putative tRNA variant and a primary LHON-associated mtDNA mutation were 40.1%. These findings suggested that mitochondrial tRNA variants represent a significant causative factor for LHON, accounting for 8.75% cases in this cohort. These new insights may lead to beneficial applications in the pathophysiology, disease management, and genetic counseling of LHON.
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Affiliation(s)
- Yanchun Ji
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, Zhejiang 310058, China; Institute of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Juanjuan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Min Liang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Feilong Meng
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, Zhejiang 310058, China; Institute of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Minglian Zhang
- Department of Ophthalmology, Hebei Provincial Eye Hospital, Xingtai, Hebei 051730, China
| | - Jun Q Mo
- Department of Pathology, Rady Children's Hospital, University of California at San Diego School of Medicine, San Diego, California 92123, USA
| | - Meng Wang
- Institute of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine and National Clinical Research Center for Child Health, Hangzhou, Zhejiang 310058, China; Institute of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China; Zhejiang Provincial Key Laboratory of Genetic & Developmental Disorders, Zhejiang University, Hangzhou, Zhejiang 310058, China; Division of Mitochondrial Biomedicine, Joint Institute of Genetics and Genome Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang, China.
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Genetic etiology of non-syndromic hearing loss in Europe. Hum Genet 2022; 141:683-696. [PMID: 35044523 DOI: 10.1007/s00439-021-02425-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 12/20/2021] [Indexed: 12/17/2022]
Abstract
Hearing impairment not etiologically associated with clinical signs in other organs (non-syndromic) is genetically heterogeneous, so that over 120 genes are currently known to be involved. The frequency of mutations in each gene and the most frequent mutations vary throughout populations. Here we review the genetic etiology of non-syndromic hearing impairment (NSHI) in Europe. Over the years, epidemiological data were scarce because of the large number of involved genes, whose screening was not cost-effective until implementation of massively parallel DNA sequencing. In Europe, the most common form of autosomal recessive NSHI is DFNB1, which accounts for 11-57% of the cases. Mutations in STRC account for 16% of the recessive cases, and only a few more (MYO15A, MYO7A, LOXHD1, USH2A, TMPRSS3, CDH23, TMC1, OTOF, OTOA, SLC26A4, ADGRV1 and TECTA) have contributions higher than 2%. As regards autosomal-dominant NSHI, DFNA22 (MYO6) and DFNA8/12 (TECTA) represent the most common forms, accounting for 21% and 18% of elucidated cases, respectively. The contribution of ACTG1 and WFS1 drops to 9% in both cases, followed by POU4F3 (6.5%), MYO7A (5%), MYH14 and COL11A2 (4% each). Four additional genes contribute 2.5% each one (MITF, KCNQ4, EYA4, SOX10) and the remaining are residually represented. X-linked hearing loss and maternally-inherited NSHI have minor contributions in most countries. Further knowledge on the genetic epidemiology of NSHI in Europe needs a standardization of the experimental approaches and a stratification of the results according to clinical features, familial history and patterns of inheritance, to facilitate comparison between studies.
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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: 11] [Impact Index Per Article: 3.7] [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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10
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Obesity associated with a novel mitochondrial tRNACys 5802A>G mutation in a Chinese family. Biosci Rep 2021; 40:221715. [PMID: 31868206 PMCID: PMC6944677 DOI: 10.1042/bsr20192153] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 12/18/2019] [Accepted: 12/19/2019] [Indexed: 01/07/2023] Open
Abstract
A Chinese family with matrilineally inherited obesity was assessed and its clinical, genetic, and molecular profiling was conducted. Obesity was observed in matrilineal relatives (3 out of 7) of a single generation (of 3 alive generations) in this family. On pedigree analysis and sequencing of their mitochondrial DNA (mtDNA), a novel homoplasmic mutation of the mitochondrial tRNACys gene (5802A>G) was identified in these individuals. This mutation correlated with a destabilized conserved base pair in this tRNA anticodon stem. Position 30 is known to be crucial for carrying out effective codon recognition and stability of tRNA. In accordance with the importance of this conserved site, we observed that the predicted structure of tRNACys with the mutation was noticeably remodeled in a molecular dynamics simulation when compared with the isoform of the wild-type. All other 46 mutations observed in the individual’s mtDNA were known variants belonging to haplogroup D4. Thus, this is the first report that provides evidence of the association between a mutation in tRNA and an enhanced risk of maternally transmissible obesity, offering more insights into obesity and its underlying nature.
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11
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Loos MA, Gomez G, Mayorga L, Caraballo RH, Eiroa HD, Obregon MG, Rugilo C, Lubieniecki F, Taratuto AL, Saccoliti M, Alonso CN, Aráoz HV. Clinical and molecular characterization of mitochondrial DNA disorders in a group of Argentinian pediatric patients. Mol Genet Metab Rep 2021; 27:100733. [PMID: 33717984 PMCID: PMC7933530 DOI: 10.1016/j.ymgmr.2021.100733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 11/02/2022] Open
Abstract
Objective To describe the clinical and molecular features of a group of Argentinian pediatric patients with mitochondrial DNA (mtDNA) disorders, and to evaluate the results of the implementation of a classical approach for the molecular diagnosis of mitochondrial diseases. Methods Clinical data from 27 patients with confirmed mtDNA pathogenic variants were obtained from a database of 89 patients with suspected mitochondrial disease, registered from 2014 to 2020. Clinical data, biochemical analysis, neuroimaging findings, muscle biopsy and molecular studies were analyzed. Results Patients were 18 females and 9 males, with ages at onset ranging from 1 week to 14 years (median = 4 years). The clinical phenotypes were: mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome (n = 11), Leigh syndrome (n = 5), Kearns-Sayre syndrome (n = 3), Chronic Progressive External Ophthalmoplegia (n = 2), Leber hereditary optic neuropathy (n = 2), myoclonic epilepsy associated with ragged-red fibers (n = 1) and reversible infantile myopathy with cytochrome-C oxidase deficiency (n = 3). Most of the patients harbored pathogenic single nucleotide variants, mainly involving mt-tRNA genes, such as MT-TL1, MT-TE and MT-TK. Other point variants were found in complex I subunits, like MT-ND6, MT-ND4, MT-ND5; or in MT-ATP6. The m.13513G > A variant in MT-ND5 and the m.9185 T > C variant in MT-ATP6 were apparently de novo. The rest of the patients presented large scale-rearrangements, either the "common" deletion or a larger deletion. Conclusions This study highlights the clinical and genetic heterogeneity of pediatric mtDNA disorders. All the cases presented with classical phenotypes, being MELAS the most frequent. Applying classical molecular methods, it was possible to achieve a genetic diagnosis in 30% of the cases, suggesting that this is an effective first approach, especially for those centers from low-middle income countries, leaving NGS studies for those patients with inconclusive results.
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Affiliation(s)
- Mariana Amina Loos
- Department of Neurology, Hospital de Pediatría "Juan P. Garrahan", Combate de los Pozos 1881, Buenos Aires 1245, Argentina
| | - Gimena Gomez
- Genomics Laboratory, Hospital de Pediatría "Juan P. Garrahan", Combate de los Pozos 1881, Buenos Aires 1245, Argentina
| | - Lía Mayorga
- Instituto de Histología y Embriología de Mendoza (IHEM, Universidad Nacional de Cuyo, CONICET), Centro Universitario UNCuyo, 5500 Mendoza, Argentina
| | - Roberto Horacio Caraballo
- Department of Neurology, Hospital de Pediatría "Juan P. Garrahan", Combate de los Pozos 1881, Buenos Aires 1245, Argentina
| | - Hernán Diego Eiroa
- Department of Inborn Errors of Metabolism, Hospital de Pediatría "Juan P. Garrahan", Combate de los Pozos 1881, Buenos Aires, 1245, Argentina
| | - María Gabriela Obregon
- Department of Medical Genetics, Hospital de Pediatría "Juan P. Garrahan", Combate de los Pozos 1881, Buenos Aires 1245, Argentina
| | - Carlos Rugilo
- Department of DiagnosticImaging, Hospital de Pediatría "Juan P. Garrahan", Combate de los Pozos 1881, Buenos Aires 1245, Argentina
| | - Fabiana Lubieniecki
- Department of Pathology, Hospital de Pediatría "Juan P. Garrahan", Combate de los Pozos 1881, Buenos Aires 1245, Argentina
| | - Ana Lía Taratuto
- Neuropathology and Neuromuscular Diseases Laboratory, Buenos Aires, Argentina
| | - María Saccoliti
- Neuropathology and Neuromuscular Diseases Laboratory, Buenos Aires, Argentina
| | - Cristina Noemi Alonso
- Genomics Laboratory, Hospital de Pediatría "Juan P. Garrahan", Combate de los Pozos 1881, Buenos Aires 1245, Argentina
| | - Hilda Verónica Aráoz
- Department of Medical Genetics, Hospital de Pediatría "Juan P. Garrahan", Combate de los Pozos 1881, Buenos Aires 1245, Argentina
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12
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Webb M, Sideris DP. Intimate Relations-Mitochondria and Ageing. Int J Mol Sci 2020; 21:ijms21207580. [PMID: 33066461 PMCID: PMC7589147 DOI: 10.3390/ijms21207580] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial dysfunction is associated with ageing, but the detailed causal relationship between the two is still unclear. We review the major phenomenological manifestations of mitochondrial age-related dysfunction including biochemical, regulatory and energetic features. We conclude that the complexity of these processes and their inter-relationships are still not fully understood and at this point it seems unlikely that a single linear cause and effect relationship between any specific aspect of mitochondrial biology and ageing can be established in either direction.
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Affiliation(s)
- Michael Webb
- Mitobridge Inc., an Astellas Company, 1030 Massachusetts Ave, Cambridge, MA 02138, USA
| | - Dionisia P Sideris
- Mitobridge Inc., an Astellas Company, 1030 Massachusetts Ave, Cambridge, MA 02138, USA
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13
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Ding Y, Teng YS, Zhuo GC, Xia BH, Leng JH. The Mitochondrial tRNAHis G12192A Mutation May Modulate the Clinical Expression of Deafness-Associated tRNAThr G15927A Mutation in a Chinese Pedigree. Curr Mol Med 2020; 19:136-146. [PMID: 30854964 DOI: 10.2174/1566524019666190308121552] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 03/02/2019] [Accepted: 03/04/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND Mutations in mitochondrial tRNA (mt-tRNA) genes have been found to be associated with both syndromic and non-syndromic hearing impairment. However, the pathophysiology underlying mt-tRNA mutations in clinical expression of hearing loss remains poorly understood. OBJECTIVE The aim of this study was to explore the potential association between mttRNA mutations and hearing loss. METHODS AND RESULTS We reported here the molecular features of a pedigree with maternally transmitted non-syndromic hearing loss. Among 12 matrilineal relatives, five of them suffered variable degree of hearing impairment, but none of them had any medical history of using aminoglycosides antibiotics (AmAn). Genetic screening of the complete mitochondrial genomes from the matrilineal relatives identified the coexistence of mt-tRNAHis G12192A and mt-tRNAThr G15927A mutations, together with a set of polymorphisms belonging to human mitochondrial haplogroup B5b1b. Interestingly, the G12192A mutation occurred 2-bp from the 3' end of the TψC loop of mt-tRNAHis, which was evolutionarily conserved from various species. In addition, the well-known G15927A mutation, which disrupted the highly conserved C-G base-pairing at the anticodon stem of mt-tRNAThr, may lead to the failure in mt-tRNA metabolism. Furthermore, a significant decreased in ATP production and an increased ROS generation were observed in polymononuclear leukocytes (PMNs) which were isolated from the deaf patients carrying these mt-tRNA mutations, suggested that the G12192A and G15927A mutations may cause mitochondrial dysfunction that was responsible for deafness. However, the absence of any functional mutations/variants in GJB2, GJB3, GJB6 and TRMU genes suggested that the nuclear genes may not play important roles in the clinical expression of non-syndromic hearing loss in this family. CONCLUSION Our data indicated that mt-tRNAHis G12192A mutation may increase the penetrance and expressivity of deafness-associated m-tRNAThr G15927A mutation in this family.
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Affiliation(s)
- Yu Ding
- Central Laboratory, Hangzhou First People's Hospital, Zhejiang University, School of Medicine, Hangzhou, China
| | - Yao-Shu Teng
- Department of Otolaryngology, Hangzhou First People's Hospital, Zhejiang University, School of Medicine, Hangzhou, China
| | - Guang-Chao Zhuo
- Central Laboratory, Hangzhou First People's Hospital, Zhejiang University, School of Medicine, Hangzhou, China
| | - Bo-Hou Xia
- Department of Pharmacy, Hunan Chinese Medical University, Changsha, China
| | - Jian-Hang Leng
- Central Laboratory, Hangzhou First People's Hospital, Zhejiang University, School of Medicine, Hangzhou, China
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14
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Zheng J, Bai X, Xiao Y, Ji Y, Meng F, Aishanjiang M, Gao Y, Wang H, Fu Y, Guan MX. Mitochondrial tRNA mutations in 887 Chinese subjects with hearing loss. Mitochondrion 2020; 52:163-172. [PMID: 32169613 DOI: 10.1016/j.mito.2020.03.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/13/2020] [Accepted: 03/09/2020] [Indexed: 01/24/2023]
Abstract
Mutations in the mitochondrial tRNAs have been reported to be the important cause of hearing loss. However, only a few cases have been identified thus far and the prevalence of mitochondrial tRNA mutations in hearing-impaired patients remain unclear. Here we performed the mutational analysis of 22 mitochondrial tRNA genes in a large cohort of 887 Han Chinese subjects with hearing loss by Sanger sequencing. The systemic evaluation of putative pathogenic variants was further carried out by frequency in controls (<1%), phylogenetic analysis, structural analysisandfunctionalprediction. As a result, a total of 147 variants on 22 tRNA genes were identified. Among these, 39 tRNA mutations (10 pathogenic and 29 likely pathogenic) which absent or present <1% in 773 Chinese controls, localized at highly conserved nucleotides, or changed the modified nucleotides, could have potential structural alterations and functional significance, thereby considered to be deafness-associated mutations. Furthermore, 44 subjects carried one of these 39 pathogenic/likely pathogenic tRNA mutations with a total prevalence of 4.96%. However, the phenotypic variability and incomplete penetrance of hearing loss in pedigrees carrying these tRNA mutations indicate the involvement of modifier factors, such as nuclear encoded genes associated with mitochondrion biogenesis, mitochondrial haplotypes, epigenetic and environmental factors. Thus, our data provide the evidence that mitochondrial tRNA mutations are the important causes of hearing loss among Chinese population. These findings further increase our knowledge on the clinical relevance of tRNA mutations in the mitochondrial genome, and should be helpful to elucidate the pathogenesis of maternal hearing loss.
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Affiliation(s)
- Jing Zheng
- Division of Medical Genetics and Genomics, and Department of Genetic and Metabolic Diseases, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang 310052, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Xiaohui Bai
- Department of Otorhinolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, Jinan, Shandong 250022, China
| | - Yun Xiao
- Division of Medical Genetics and Genomics, and Department of Genetic and Metabolic Diseases, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang 310052, China; Department of Otorhinolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, Jinan, Shandong 250022, China
| | - Yanchun Ji
- Division of Medical Genetics and Genomics, and Department of Genetic and Metabolic Diseases, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang 310052, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Feilong Meng
- Division of Medical Genetics and Genomics, and Department of Genetic and Metabolic Diseases, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang 310052, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Maerhaba Aishanjiang
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yinglong Gao
- Division of Medical Genetics and Genomics, and Department of Genetic and Metabolic Diseases, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang 310052, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Haibo Wang
- Department of Otorhinolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, Jinan, Shandong 250022, China.
| | - Yong Fu
- Division of Medical Genetics and Genomics, and Department of Genetic and Metabolic Diseases, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang 310052, China; Department of Otorhinolaryngology Head and Neck Surgery, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang 310052, China.
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, and Department of Genetic and Metabolic Diseases, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, Zhejiang 310052, China; Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
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15
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Gong S, Wang X, Meng F, Cui L, Yi Q, Zhao Q, Cang X, Cai Z, Mo JQ, Liang Y, Guan MX. Overexpression of mitochondrial histidyl-tRNA synthetase restores mitochondrial dysfunction caused by a deafness-associated tRNAHis mutation. J Biol Chem 2020. [DOI: 10.1016/s0021-9258(17)49906-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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16
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Gong S, Wang X, Meng F, Cui L, Yi Q, Zhao Q, Cang X, Cai Z, Mo JQ, Liang Y, Guan MX. Overexpression of mitochondrial histidyl-tRNA synthetase restores mitochondrial dysfunction caused by a deafness-associated tRNA His mutation. J Biol Chem 2019; 295:940-954. [PMID: 31819004 DOI: 10.1074/jbc.ra119.010998] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/27/2019] [Indexed: 01/19/2023] Open
Abstract
The deafness-associated m.12201T>C mutation affects the A5-U68 base-pairing within the acceptor stem of mitochondrial tRNAHis The primary defect in this mutation is an alteration in tRNAHis aminoacylation. Here, we further investigate the molecular mechanism of the deafness-associated tRNAHis 12201T>C mutation and test whether the overexpression of the human mitochondrial histidyl-tRNA synthetase gene (HARS2) in cytoplasmic hybrid (cybrid) cells carrying the m.12201T>C mutation reverses mitochondrial dysfunctions. Using molecular dynamics simulations, we demonstrate that the m.12201T>C mutation perturbs the tRNAHis structure and function, supported by decreased melting temperature, conformational changes, and instability of mutated tRNA. We show that the m.12201T>C mutation-induced alteration of aminoacylation tRNAHis causes mitochondrial translational defects and respiratory deficiency. We found that the transfer of HARS2 into the cybrids carrying the m.12201T>C mutation raises the levels of aminoacylated tRNAHis from 56.3 to 75.0% but does not change the aminoacylation of other tRNAs. Strikingly, HARS2 overexpression increased the steady-state levels of tRNAHis and of noncognate tRNAs, including tRNAAla, tRNAGln, tRNAGlu, tRNALeu(UUR), tRNALys, and tRNAMet, in cells bearing the m.12201T>C mutation. This improved tRNA metabolism elevated the efficiency of mitochondrial translation, activities of oxidative phosphorylation complexes, and respiration capacity. Furthermore, HARS2 overexpression markedly increased mitochondrial ATP levels and membrane potential and reduced production of reactive oxygen species in cells carrying the m.12201T>C mutation. These results indicate that HARS2 overexpression corrects the mitochondrial dysfunction caused by the tRNAHis mutation. These findings provide critical insights into the pathophysiology of mitochondrial disease and represent a step toward improved therapeutic interventions for mitochondrial disorders.
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Affiliation(s)
- Shasha Gong
- Taizhou University Hospital, Taizhou University, Taizhou, Zhejiang 318000, China.,Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xiaoqiong Wang
- Department of Otolaryngology, Taizhou Municipal Hospital, Taizhou, Zhejiang 318000, China.,Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Feilong Meng
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China.,Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Limei Cui
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Qiuzi Yi
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Qiong Zhao
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xiaohui Cang
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Zhiyi Cai
- Department of Otolaryngology, Taizhou Municipal Hospital, Taizhou, Zhejiang 318000, China
| | - Jun Qin Mo
- Department of Pathology, Rady Children's Hospital, University of California School of Medicine, San Diego, California 92123
| | - Yong Liang
- Taizhou University Hospital, Taizhou University, Taizhou, Zhejiang 318000, China
| | - Min-Xin Guan
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China .,Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Key Laboratory of Reproductive Genetics, Ministry of Education of PRC, Zhejiang University, Hangzhou, Zhejiang 310058, China.,Joint Institute of Genetics and Genomic Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang 310058, China
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17
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Fan W, Zheng J, Kong W, Cui L, Aishanjiang M, Yi Q, Wang M, Cang X, Tang X, Chen Y, Mo JQ, Sondheimer N, Ge W, Guan MX. Contribution of a mitochondrial tyrosyl-tRNA synthetase mutation to the phenotypic expression of the deafness-associated tRNA Ser(UCN) 7511A>G mutation. J Biol Chem 2019; 294:19292-19305. [PMID: 31685661 DOI: 10.1074/jbc.ra119.010598] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 10/29/2019] [Indexed: 01/01/2023] Open
Abstract
Nuclear modifier genes have been proposed to modify the phenotypic expression of mitochondrial DNA mutations. Using a targeted exome-sequencing approach, here we found that the p.191Gly>Val mutation in mitochondrial tyrosyl-tRNA synthetase 2 (YARS2) interacts with the tRNASer(UCN) 7511A>G mutation in causing deafness. Strikingly, members of a Chinese family bearing both the YARS2 p.191Gly>Val and m.7511A>G mutations displayed much higher penetrance of deafness than those pedigrees carrying only the m.7511A>G mutation. The m.7511A>G mutation changed the A4:U69 base-pairing to G4:U69 pairing at the aminoacyl acceptor stem of tRNASer(UCN) and perturbed tRNASer(UCN) structure and function, including an increased melting temperature, altered conformation, instability, and aberrant aminoacylation of mutant tRNA. Using lymphoblastoid cell lines derived from symptomatic and asymptomatic members of these Chinese families and control subjects, we show that cell lines harboring only the m.7511A>G or p.191Gly>Val mutation revealed relatively mild defects in tRNASer(UCN) or tRNATyr metabolism, respectively. However, cell lines harboring both m.7511A>G and p.191Gly>Val mutations displayed more severe defective aminoacylations and lower tRNASer(UCN) and tRNATyr levels, aberrant aminoacylation, and lower levels of other tRNAs, including tRNAThr, tRNALys, tRNALeu(UUR), and tRNASer(AGY), than those in the cell lines carrying only the m.7511A>G or p.191Gly>Val mutation. Furthermore, mutant cell lines harboring both m.7511A>G and p.191Gly>Val mutations exhibited greater decreases in the levels of mitochondrial translation, respiration, and mitochondrial ATP and membrane potentials, along with increased production of reactive oxygen species. Our findings provide molecular-level insights into the pathophysiology of maternally transmitted deafness arising from the synergy between tRNASer(UCN) and mitochondrial YARS mutations.
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Affiliation(s)
- Wenlu Fan
- Division of Medical Genetics and Genomics, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Attardi Institute of Biomedicine, School of Life Sciences and Laboratory Medicine, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China
| | - Jing Zheng
- Division of Medical Genetics and Genomics, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Wanzhong Kong
- Attardi Institute of Biomedicine, School of Life Sciences and Laboratory Medicine, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China
| | - Limei Cui
- Division of Medical Genetics and Genomics, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Maerhaba Aishanjiang
- Division of Medical Genetics and Genomics, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Qiuzi Yi
- Division of Medical Genetics and Genomics, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Min Wang
- Attardi Institute of Biomedicine, School of Life Sciences and Laboratory Medicine, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China
| | - Xiaohui Cang
- Division of Medical Genetics and Genomics, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Xiaowen Tang
- Attardi Institute of Biomedicine, School of Life Sciences and Laboratory Medicine, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China
| | - Ye Chen
- Division of Medical Genetics and Genomics, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Jun Qin Mo
- Department of Pathology, Rady Children's Hospital, University of California School of Medicine, San Diego, California 92123
| | - Neal Sondheimer
- Department of Molecular Genetics, University of Toronto School of Medicine and the Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Wanzhong Ge
- Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China .,Institute of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Key Laboratory of Reproductive Genetics, Ministry of Education of PRC, Zhejiang University, Hangzhou, Zhejiang 310058, China.,Joint Institute of Genetics and Genome Medicine between Zhejiang University and the University of Toronto, Hangzhou, Zhejiang 310058, China
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18
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Lyu Y, Xu M, Chen J, Ji Y, Guan MX, Zhang J. Frequency and spectrum of MT-TT variants associated with Leber's hereditary optic neuropathy in a Chinese cohort of subjects. MITOCHONDRIAL DNA PART B-RESOURCES 2019; 4:2266-2280. [PMID: 33365504 PMCID: PMC7687527 DOI: 10.1080/23802359.2019.1627921] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Leber’s hereditary optic neuropathy (LHON) is a maternally inherited eye disease. In our previous investigations, we have reported the spectrum and frequency of mitochondrial MT-ND1, MT-ND4 and MT-ND6 gene in Chinese LHON population. This study aimed to assess the molecular epidemiology of MT-TT mutations in Chinese families with LHON. A cohort of 352 Chinese Han probands lacking the known LHON-associated mtDNA mutations and 376 control subjects underwent molecular analysis of mtDNA. All variants were evaluated for evolutionary conservation, structural and functional consequences. Fifteen variants were identified in the MT-TT gene by mitochondrial genome analysis of LHON pedigrees, which was substantially higher than that of individuals from general Chinese populations. The incidences of the two known LHON-associated mutations, m.15927G > A and m.15951A > G, were 2.27% and 1.14%, respectively. Nine putative LHON-associated variants were identified in 20 probands, translated into 2.1% cases of this cohort. Moreover, mtDNAs in 41 probands carrying the MT-TT mutation(s) were widely dispersed among nine Eastern Asian haplogroups. Our results suggest that the MT-TT gene is a mutational hotspot for these 352 Chinese families lacking the known LHON-associated mutations. These data further showed the molecular epidemiology of MT-TT mutations in Chinese Han LHON pedigrees.
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Affiliation(s)
- Yuanyuan Lyu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Man Xu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jie Chen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - YanChun Ji
- School of Medicine, Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Min-Xin Guan
- School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China.,School of Medicine, Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Juanjuan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China.,School of Laboratory Medicine and Life Sciences, Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
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19
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Cosentino C, Cnop M, Igoillo-Esteve M. The tRNA Epitranscriptome and Diabetes: Emergence of tRNA Hypomodifications as a Cause of Pancreatic β-Cell Failure. Endocrinology 2019; 160:1262-1274. [PMID: 30907926 DOI: 10.1210/en.2019-00098] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 03/15/2019] [Indexed: 01/26/2023]
Abstract
tRNAs are crucial noncoding RNA molecules that serve as amino acid carriers during protein synthesis. The transcription of tRNA genes is a highly regulated process. The tRNA pool is tissue and cell specific, it varies during development, and it is modulated by the environment. tRNAs are highly posttranscriptionally modified by specific tRNA-modifying enzymes. The tRNA modification signature of a cell determines the tRNA epitranscriptome. Perturbations in the tRNA epitranscriptome, as a consequence of mutations in tRNAs and tRNA-modifying enzymes or environmental exposure, have been associated with human disease, including diabetes. tRNA fragmentation induced by impaired tRNA modifications or dietary factors has been linked to pancreatic β-cell demise and paternal inheritance of metabolic traits. Herein, we review recent findings that associate tRNA epitranscriptome perturbations with diabetes.
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Affiliation(s)
- Cristina Cosentino
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels, Belgium
| | - Miriam Cnop
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium
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20
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Cochlear implantation for hearing loss due to an A8296G mitochondrial DNA mutation. OTOLARYNGOLOGY CASE REPORTS 2019. [DOI: 10.1016/j.xocr.2019.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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21
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Ding Y, Liu Q, Teng YS, Zheng H, Leng JH. The mitochondrial tRNA Thr G15930A may be a novel mutation associated with hearing impairment. MITOCHONDRIAL DNA PART B 2019. [DOI: 10.1080/23802359.2019.1597648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Yu Ding
- Central laboratory, Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou, PR China
| | - Qi Liu
- Department of laboratory medicine, Shaoxing People’s Hospital, Shaoxing Hospital of Zhejiang University School of Medicine, Shaoxing, PR China
| | - Yao-Shu Teng
- Department of Otorhinolaryngology, Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou, PR China
| | - Hui Zheng
- Central laboratory, Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou, PR China
| | - Jian-Hang Leng
- Central laboratory, Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou, PR China
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22
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Cosentino C, Toivonen S, Diaz Villamil E, Atta M, Ravanat JL, Demine S, Schiavo A, Pachera N, Deglasse JP, Jonas JC, Balboa D, Otonkoski T, Pearson ER, Marchetti P, Eizirik DL, Cnop M, Igoillo-Esteve M. Pancreatic β-cell tRNA hypomethylation and fragmentation link TRMT10A deficiency with diabetes. Nucleic Acids Res 2018; 46:10302-10318. [PMID: 30247717 PMCID: PMC6212784 DOI: 10.1093/nar/gky839] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 08/17/2018] [Accepted: 09/10/2018] [Indexed: 12/20/2022] Open
Abstract
Transfer RNAs (tRNAs) are non-coding RNA molecules essential for protein synthesis. Post-transcriptionally they are heavily modified to improve their function, folding and stability. Intronic polymorphisms in CDKAL1, a tRNA methylthiotransferase, are associated with increased type 2 diabetes risk. Loss-of-function mutations in TRMT10A, a tRNA methyltransferase, are a monogenic cause of early onset diabetes and microcephaly. Here we confirm the role of TRMT10A as a guanosine 9 tRNA methyltransferase, and identify tRNAGln and tRNAiMeth as two of its targets. Using RNA interference and induced pluripotent stem cell-derived pancreatic β-like cells from healthy controls and TRMT10A-deficient patients we demonstrate that TRMT10A deficiency induces oxidative stress and triggers the intrinsic pathway of apoptosis in β-cells. We show that tRNA guanosine 9 hypomethylation leads to tRNAGln fragmentation and that 5'-tRNAGln fragments mediate TRMT10A deficiency-induced β-cell death. This study unmasks tRNA hypomethylation and fragmentation as a hitherto unknown mechanism of pancreatic β-cell demise relevant to monogenic and polygenic forms of diabetes.
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Affiliation(s)
- Cristina Cosentino
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Sanna Toivonen
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Esteban Diaz Villamil
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Mohamed Atta
- CEA/Grenoble, DRF/BIG/LCBM UMR5249, Grenoble, France
| | - Jean-Luc Ravanat
- Université Grenoble Alpes, CEA, CNRS INAC, SyMMES UMR 5819, Grenoble, France
| | - Stéphane Demine
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Andrea Alex Schiavo
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Nathalie Pachera
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Jean-Philippe Deglasse
- Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique, Pôle d’ Endocrinologie, Diabète et Nutrition, Brussels, Belgium
| | - Jean-Christophe Jonas
- Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique, Pôle d’ Endocrinologie, Diabète et Nutrition, Brussels, Belgium
| | - Diego Balboa
- Research Programs Unit, Molecular Neurology and Biomedicum Stem Cell Centre, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Timo Otonkoski
- Research Programs Unit, Molecular Neurology and Biomedicum Stem Cell Centre, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Ewan R Pearson
- Division of Cardiovascular and Diabetes Medicine, Medical Research Institute, Ninewells Hospital and Medical School, Dundee, UK
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Décio L Eizirik
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Miriam Cnop
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 1070 Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, 1070 Brussels, Belgium
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23
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Kumbhar NM, Gopal JS. Structural significance of hypermodified nucleoside 5-carboxymethylaminomethyluridine (cmnm 5U) from 'wobble' (34th) position of mitochondrial tRNAs: Molecular modeling and Markov state model studies. J Mol Graph Model 2018; 86:66-83. [PMID: 30336453 DOI: 10.1016/j.jmgm.2018.10.004] [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: 03/06/2018] [Revised: 10/02/2018] [Accepted: 10/04/2018] [Indexed: 11/28/2022]
Abstract
A quantum chemical semi-empirical RM1 approach was used to deduce the structural role of hypermodified nucleoside 5-carboxymethylaminomethyluridine 5'-monophosphate (pcmnm5U) from 'wobble' (34th) position of mitochondrial tRNAs. The energetically preferred pcmnm5U(34) adopted a 'skew' conformation for C5-substituted side chain (-CH2-NH2+-CH2-COO-) moiety that orient towards the 5'-ribose-phosphate backbone, which support 'anti' orientation of glycosyl (χ34) torsion angle. Preferred conformation of pcmnm5U(34) was stabilized by O(4) … HC(10), O1P⋯HN(11), O(15) … HN(11), O(15) … HC(10), O4' … HC(6) and O(2) … HC2' hydrogen bonding interactions. The high flexibility of side chain moiety displayed different structural properties for pcmnm5U(34). Three different conformations of pcmnm5U(34) were observed in molecular dynamics simulations and Markov state model studies. The unmodified uracil revealed 'syn' and 'anti' orientations for glycosyl (χ34) torsion angle that substantiate the role of "-CH2-NH2+-CH2-COO-" moiety in maintaining the 'anti' orientation of pcmnm5U(34). The preferred conformation of pcmnm5U(34) helps to recognize Guanosine more proficiently than Adenosine from the third position of codons. The role of pcmnm5U(34) in tRNA biogenesis paves the way to understand its structural significance in usual mitochondrial metabolism and respiration.
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Affiliation(s)
- Navanath M Kumbhar
- Garware Research Centre, Department of Chemistry, Savitribai Phule Pune University (Formerly University of Pune), Pune, 411007, India.
| | - Janhavi S Gopal
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University (Formerly University of Pune), Pune, 411007, India
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24
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Xue L, Chen Y, Tang X, Yao J, Huang H, Wang M, Ye S, Wang M, Guan MX. A deafness-associated mitochondrial DNA mutation altered the tRNA Ser(UCN) metabolism and mitochondrial function. Mitochondrion 2018; 46:370-379. [PMID: 30336267 DOI: 10.1016/j.mito.2018.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/09/2018] [Accepted: 10/08/2018] [Indexed: 11/28/2022]
Abstract
Mutations in mitochondrial DNA (mtDNA) have been associated with deafness and their pathophysiology remains poorly understood. In this study, we investigated the pathogenic mechanism of deafness-associated 7505A > G variant in the mitochondrial tRNASer(UCN). The m.7505A > G variant affected the highly conserved adenine at position 11 (A11), disrupted the highly conserved A11-U24 base-pairing of DHU stem of tRNASer(UCN) and introduced a tertiary base pairing (G11-C56) with the C56 in the TΨC loop. We therefore hypothesized that the m.7505A > G variant altered both structure and function of tRNASer(UCN). We demonstrated that the m.7505A > G variant perturbed the conformation and stability of tRNASer(UCN), as indicated by an increased melting temperature and electrophoretic mobility of the mutated tRNA compared with the wild type molecule. Using the cybrids constructed by transferring mitochondria from the Chinese family into mitochondrial DNA (mtDNA)-less cells, we demonstrated the m.7505A > G variant led to significantly decreased steady-state levels of tRNASer(UCN) in the mutant cybrids, as compared with those of control cybrids. The aberrant tRNASer(UCN) metabolism resulted in the variable decreases in mtDNA-encoded polypeptides in the mutant cybrids. Furthermore, we demonstrated that the m.7505A > G variant decreased the activities of mitochondrial respiratory complexes I, III and IV, markedly diminished mitochondrial ATP levels and membrane potential, and increased the production of reactive oxygen species in the mutant cybrids. These results demonstrated that the m.7505A > G variant affected both structure and function of tRNASer(UCN) and consequently altered mitochondrial function. Our findings highlighted critical insights into the pathophysiology of maternally inherited deafness, which is manifested by the aberrant tRNA metabolism.
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Affiliation(s)
- Ling Xue
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Zhejiang 325035, China
| | - Yaru Chen
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Zhejiang 325035, China; Institute of Genetics, Zhejiang University School of Medicine, Zhejiang, Hangzhou 310058, China; Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Zhejiang, Hangzhou, China
| | - Xiaowen Tang
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Zhejiang 325035, China
| | - Juan Yao
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Zhejiang 325035, China
| | - Huimin Huang
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Zhejiang 325035, China
| | - Min Wang
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Zhejiang 325035, China
| | - Shixin Ye
- Laboratory of Computational and Quantitative Biology, Université Pierre-et-Marie-Curie, CNRS, Paris, France
| | - Meng Wang
- Institute of Genetics, Zhejiang University School of Medicine, Zhejiang, Hangzhou 310058, China; Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Zhejiang, Hangzhou, China
| | - Min-Xin Guan
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Zhejiang 325035, China; Institute of Genetics, Zhejiang University School of Medicine, Zhejiang, Hangzhou 310058, China; Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Zhejiang, Hangzhou, China; Key Laboratory of Reproductive Genetics, Ministry of Education of PRC, Zhejiang University, Hangzhou, China; Joint Institute of Genetics and Genomic Medicine, University of Toronto, Zhejiang University, Hangzhou, Zhejiang, China.
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25
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Cui Y, He DJ. Mitochondrial tRNAIle A4317G mutation may be associated with hearing impairment in a Han Chinese family. Mol Med Rep 2018; 18:5159-5165. [PMID: 30272361 DOI: 10.3892/mmr.2018.9519] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 07/31/2018] [Indexed: 11/05/2022] Open
Abstract
Mutations in the mitochondrial genome have been identified to be associated with hearing loss. The aim of the present study was to investigate the role of mitochondrial DNA (mtDNA) variants in a Chinese family with hearing loss. Polymerase chain reaction (PCR)‑Sanger sequencing was used to screen the mtDNA variants and nuclear genes [gap junction protein β2 (GJB2) and transfer (t)RNA 5‑methylaminomethyle‑2‑thiouridylate methyltransferase (TRMU)]; in addition, the mtDNA copy number was determined by quantitative PCR. The present study characterized the molecular features of a Chinese family with maternally‑inherited hearing loss and identified mtDNA A1555G and tRNAIle A4317G mutations. The A4317G mutation was localized at the TΨC arm of tRNAIle (position 59) and created a novel base‑pairing (G59‑C54), which may alter the secondary structure of the tRNA. In addition, patients carrying the A4317G mutation exhibited a lower mtDNA copy number compared with the controls, suggesting that this mutation may cause mitochondrial dysfunction that is responsible for the deafness. However, no functional variants in the GJB2 and TRMU genes were detected. mtDNA A1555G and A4317G mutations may contribute to the clinical manifestation of hearing loss in this family.
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Affiliation(s)
- Yong Cui
- Department of Otolaryngology, The PLA 254 Hospital, Tianjin 300142, P.R. China
| | - Duan-Jun He
- Department of Otolaryngology, The PLA 254 Hospital, Tianjin 300142, P.R. China
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26
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Aravintha Siva M, Mahalakshmi R, Bhakta-Guha D, Guha G. Gene therapy for the mitochondrial genome: Purging mutations, pacifying ailments. Mitochondrion 2018; 46:195-208. [PMID: 29890303 DOI: 10.1016/j.mito.2018.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 05/24/2018] [Accepted: 06/07/2018] [Indexed: 12/21/2022]
Abstract
In the recent years, the reported cases of mitochondrial disorders have reached a colossal number. These disorders spawn a sundry of pathological conditions, which lead to pernicious symptoms and even fatality. Due to the unpredictable etiologies, mitochondrial diseases are putatively referred to as "mystondria" (mysterious diseases of mitochondria). Although present-day research has greatly improved our understanding of mitochondrial disorders, effective therapeutic interventions are still at the precursory stage. The conundrum becomes further complicated because these pathologies might occur due to either mitochondrial DNA (mtDNA) mutations or due to mutations in the nuclear DNA (nDNA), or both. While correcting nDNA mutations by using gene therapy (replacement of defective genes by delivering wild-type (WT) ones into the host cell, or silencing a dominant mutant allele that is pathogenic) has emerged as a promising strategy to address some mitochondrial diseases, the complications in correcting the defects of mtDNA in order to renovate mitochondrial functions have remained a steep challenge. In this review, we focus specifically on the selective gene therapy strategies that have demonstrated prospects in targeting the pathological mutations in the mitochondrial genome, thereby treating mitochondrial ailments.
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Affiliation(s)
- M Aravintha Siva
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India
| | - R Mahalakshmi
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India
| | - Dipita Bhakta-Guha
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India.
| | - Gunjan Guha
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India.
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27
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Meng F, He Z, Tang X, Zheng J, Jin X, Zhu Y, Ren X, Zhou M, Wang M, Gong S, Mo JQ, Shu Q, Guan MX. Contribution of the tRNA Ile 4317A→G mutation to the phenotypic manifestation of the deafness-associated mitochondrial 12S rRNA 1555A→G mutation. J Biol Chem 2018; 293:3321-3334. [PMID: 29348176 DOI: 10.1074/jbc.ra117.000530] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 01/14/2018] [Indexed: 12/28/2022] Open
Abstract
The 1555A→G mutation in mitochondrial 12S rRNA has been associated with aminoglycoside-induced and non-syndromic deafness in many individuals worldwide. Mitochondrial genetic modifiers are proposed to influence the phenotypic expression of m.1555A→G mutation. Here, we report that a deafness-susceptibility allele (m.4317A→G) in the tRNAIle gene modulates the phenotype expression of m.1555A→G mutation. Strikingly, a large Han Chinese pedigree carrying both m.4317A→G and m.1555A→G mutations exhibited much higher penetrance of deafness than those carrying only the m.1555A→G mutation. The m.4317A→G mutation affected a highly conserved adenine at position 59 in the T-loop of tRNAIle We therefore hypothesized that the m.4317A→G mutation alters both structure and function of tRNAIle Using lymphoblastoid cell lines derived from members of Chinese families (three carrying both m.1555A→G and m.4317A→G mutations, three harboring only m.1555A→G mutation, and three controls lacking these mutations), we found that the cell lines bearing both m.4317A→G and m.1555A→G mutations exhibited more severe mitochondrial dysfunctions than those carrying only the m.1555A→G mutation. We also found that the m.4317A→G mutation perturbed the conformation, stability, and aminoacylation efficiency of tRNAIle These m.4317A→G mutation-induced alterations in tRNAIle structure and function aggravated the defective mitochondrial translation and respiratory phenotypes associated with the m.1555A→G mutation. Furthermore, mutant cell lines bearing both m.4317A→G and m.1555A→G mutations exhibited greater reductions in the mitochondrial ATP levels and membrane potentials and increasing production of reactive oxygen species than those carrying only the m.1555A→G mutation. Our findings provide new insights into the pathophysiology of maternally inherited deafness arising from the synergy between mitochondrial 12S rRNA and tRNA mutations.
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Affiliation(s)
- Feilong Meng
- From the Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China.,the Institute of Genetics
| | - Zheyun He
- the Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, and.,the Institute of Liver Diseases, Ningbo Secondary Hospital, Ningbo, Zhejiang 315010, China
| | - Xiaowen Tang
- the Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, and
| | - Jing Zheng
- From the Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China.,the Institute of Genetics
| | | | - Yi Zhu
- Department of Otolaryngology, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Xiaoyan Ren
- the Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, and
| | - Mi Zhou
- From the Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China.,the Institute of Genetics
| | - Meng Wang
- From the Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China.,the Institute of Genetics
| | - Shasha Gong
- the Institute of Genetics.,the School of Medicine, Taizhou College, Taizhou, Zhejiang 318000, China, and
| | - Jun Qin Mo
- the Department of Pathology, Rady Children's Hospital, University of California at San Diego, San Diego, California 92123
| | - Qiang Shu
- From the Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China,
| | - Min-Xin Guan
- From the Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310052, China, .,the Institute of Genetics.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, and.,Joint Institute of Genetics and Genome Medicine between Zhejiang University and University of Toronto, Zhejiang University, Hangzhou, Zhejiang 310058, China
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28
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Zhou M, Wang M, Xue L, Lin Z, He Q, Shi W, Chen Y, Jin X, Li H, Jiang P, Guan MX. A hypertension-associated mitochondrial DNA mutation alters the tertiary interaction and function of tRNA Leu(UUR). J Biol Chem 2017; 292:13934-13946. [PMID: 28679533 DOI: 10.1074/jbc.m117.787028] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 07/03/2017] [Indexed: 01/10/2023] Open
Abstract
Several mitochondrial tRNA mutations have been associated with hypertension, but their pathophysiology remains poorly understood. In this report, we identified a novel homoplasmic 3253T→C mutation in the mitochondrial tRNALeu(UUR) gene in a Han Chinese family with maternally inherited hypertension. The m.3253T→C mutation affected a highly conserved uridine at position 22 at the D-stem of tRNALeu(UUR), introducing a G-C base pairing (G13-C22) at the D-stem and a tertiary base pairing (C22-G46) between the D-stem and the variable loop. We therefore hypothesized that the m.3253T→C mutation altered both the structure and function of tRNALeu(UUR) Using cytoplasmic hybrid (cybrid) cell lines derived from this Chinese family, we demonstrated that the m.3253T→C mutation perturbed the conformation and stability of tRNALeu(UUR), as suggested by faster electrophoretic mobility of mutated tRNA relative to the wild-type molecule. Northern blot analysis revealed an ∼45% decrease in the steady-state level of tRNALeu(UUR) in the mutant cell lines carrying the m.3253T→C mutation, as compared with control cell lines. Moreover, an ∼35% reduction in aminoacylation efficiency of tRNALeu(UUR) was observed in the m.3253T→C mutant cells. These alterations in tRNALeu(UUR) metabolism impaired mitochondrial translation, especially for those polypeptides with a high proportion of Leu(UUR) codons, such as ND6. Furthermore, we demonstrated that the m.3253T→C mutation decreased the activities of mitochondrial complexes I and V, markedly diminished mitochondrial ATP levels and membrane potential, and increased the production of reactive oxygen species in the cells. In conclusion, our findings may provide new insights into the pathophysiology of maternally inherited hypertension.
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Affiliation(s)
- Mi Zhou
- From the Division of Medical Genetics and Genomics, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, Zhejiang, China,; Institute of Genetics and Zhejiang University, Hangzhou 310058, Zhejiang, China
| | - Meng Wang
- From the Division of Medical Genetics and Genomics, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, Zhejiang, China,; Institute of Genetics and Zhejiang University, Hangzhou 310058, Zhejiang, China
| | - Ling Xue
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou 325600, Zhejiang, China
| | - Zhi Lin
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou 325600, Zhejiang, China
| | - Qiufen He
- Institute of Genetics and Zhejiang University, Hangzhou 310058, Zhejiang, China
| | - Wenwen Shi
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou 325600, Zhejiang, China
| | - Yaru Chen
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou 325600, Zhejiang, China
| | - Xiaofen Jin
- Institute of Genetics and Zhejiang University, Hangzhou 310058, Zhejiang, China
| | - Haiying Li
- Department of Cardiology, First Affiliated Hospital, Wenzhou Medical University, Wenzhou 325600, Zhejiang, China
| | - Pingping Jiang
- From the Division of Medical Genetics and Genomics, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, Zhejiang, China,; Institute of Genetics and Zhejiang University, Hangzhou 310058, Zhejiang, China
| | - Min-Xin Guan
- From the Division of Medical Genetics and Genomics, Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, Zhejiang, China,; Institute of Genetics and Zhejiang University, Hangzhou 310058, Zhejiang, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310058, Zhejiang, China,; Joint Institute of Genetics and Genomic Medicine between Zhejiang University and University of Toronto, Hangzhou 310058, Zhejiang, China.
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29
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Chen X, Nie Z, Wang F, Wang J, Liu XW, Zheng J, Guo YF, Guan MX. Late onset nonsyndromic hearing loss in a Dongxiang Chinese family is associated with the 593T>C variant in the mitochondrial tRNA Phe gene. Mitochondrion 2017; 35:111-118. [PMID: 28579530 DOI: 10.1016/j.mito.2017.05.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 05/31/2017] [Accepted: 05/31/2017] [Indexed: 11/19/2022]
Abstract
We report here the clinical, genetic, molecular and biochemical characterization of a four-generation Dongxiang Chinese pedigree with suggestively maternally transmitted non-syndromic hearing loss. Five of 10 matrilineal relatives exhibited variable severity and age at onset of sensorineural hearing loss. The average ages at onset of hearing loss in matrilineal relatives of this family were 29years. Molecular analysis of their mitochondrial genomes identified the tRNAPhe 593T>C variant belonging to Asian haplogroup G2a2a. The m.593T>C variant resided at the position 17 of DHU-loop, where the position is important for the structure and function of tRNA. It was anticipated that the m.593T>C variant altered the structure and function of tRNAPhe. By using lymphoblastoid cell lines derived from the Chinese family, we showed a 46% decreases in the steady-state level of tRNAPhe in mutant cell lines. Western blotting analysis showed ∼35% reduction in the levels of mitochondrial translation in mutant cell lines carrying the m.593T>C variant. Impaired mitochondrial translation is apparently a primary contributor to the marked reduction in the rate of respiratory capacity. The respiratory deficiency lowed mitochondrial ATP production in the mutant cell lines. These data provide the evidence that mitochondrial dysfunctions caused by the m.593T>C variant lead to late-onset nonsyndromic hearing loss. Thus, our findings may provide the new insights into the understanding of pathophysiology and valuable information for management and treatment of maternally inherited hearing loss.
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Affiliation(s)
- Xiaowan Chen
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, Lanzhou, Gansu730000, China; Institute of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China; Department of Otolaryngology-Head and Neck Surgery, Lanzhou University First Hospital, Lanzhou, Gansu 730000, China
| | - Zhipeng Nie
- Institute of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Fang Wang
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, Lanzhou, Gansu730000, China
| | - Jianchao Wang
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, Lanzhou, Gansu730000, China
| | - Xiao-Wen Liu
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, Lanzhou, Gansu730000, China
| | - Jing Zheng
- Institute of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yu-Fen Guo
- Department of Otolaryngology-Head and Neck Surgery, Lanzhou University Second Hospital, Lanzhou, Gansu730000, China; Health and Family Planning Commission of Gansu Province, Lanzhou, Gansu 730000, China.
| | - Min-Xin Guan
- Institute of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, Zhejiang 310058, China.
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30
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Subathra M, Ramesh A, Selvakumari M, Karthikeyen NP, Srisailapathy CRS. Genetic Epidemiology of Mitochondrial Pathogenic Variants Causing Nonsyndromic Hearing Loss in a Large Cohort of South Indian Hearing Impaired Individuals. Ann Hum Genet 2017; 80:257-73. [PMID: 27530448 DOI: 10.1111/ahg.12161] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 05/16/2016] [Indexed: 01/28/2023]
Abstract
Mitochondria play a critical role in the generation of metabolic energy in the form of ATP. Tissues and organs that are highly dependent on aerobic metabolism are involved in mitochondrial disorders including nonsyndromic hearing loss (NSHL). Seven pathogenic variants leading to NSHL have so far been reported on two mitochondrial genes: MT-RNR1 encoding 12SrRNA and MT-TS1 encoding tRNA for Ser((UCN)) . We screened 729 prelingual NSHL subjects to determine the prevalence of MT-RNR1 variants at position m.961, m.1555A>G and m.1494C>T, and MT-TS1 m.7445A>G, m.7472insC m.7510T>C and m.7511T>C variants. Mitochondrial pathogenic variants were found in eight probands (1.1%). Five of them were found to have the m.1555A>G variant, two others had m.7472insC and one proband had m.7444G>A. The extended relatives of these probands showed variable degrees of hearing loss and age at onset. This study shows that mitochondrial pathogenic alleles contribute to about 1% prelingual hearing loss. This study will henceforth provide the reference for the prevalence of mitochondrial pathogenic alleles in the South Indian population, which to date has not been estimated. The m.1555A>G variant is a primary predisposing genetic factor for the development of hearing loss. Our study strongly suggests that mitochondrial genotyping should be considered for all hearing impaired individuals and particularly in families where transmission is compatible with maternal inheritance, after ruling out the most common variants.
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Affiliation(s)
- Mahalingam Subathra
- Department of Genetics, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Arabandi Ramesh
- Department of Genetics, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Mathiyalagan Selvakumari
- Department of Genetics, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - N P Karthikeyen
- DOAST (Doctrine Oriented Art of Symbiotic Treatment) Hearing Care Center and Integrated Therapy Center for Autism, Anna Nagar West, Chennai, India
| | - C R Srikumari Srisailapathy
- Department of Genetics, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
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Meng F, Cang X, Peng Y, Li R, Zhang Z, Li F, Fan Q, Guan AS, Fischel-Ghosian N, Zhao X, Guan MX. Biochemical Evidence for a Nuclear Modifier Allele (A10S) in TRMU (Methylaminomethyl-2-thiouridylate-methyltransferase) Related to Mitochondrial tRNA Modification in the Phenotypic Manifestation of Deafness-associated 12S rRNA Mutation. J Biol Chem 2017; 292:2881-2892. [PMID: 28049726 DOI: 10.1074/jbc.m116.749374] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 12/15/2016] [Indexed: 11/06/2022] Open
Abstract
Nuclear modifier gene(s) was proposed to modulate the phenotypic expression of mitochondrial DNA mutation(s). Our previous investigations revealed that a nuclear modifier allele (A10S) in TRMU (methylaminomethyl-2-thiouridylate-methyltransferase) related to tRNA modification interacts with 12S rRNA 1555A→G mutation to cause deafness. The A10S mutation resided at a highly conserved residue of the N-terminal sequence. It was hypothesized that the A10S mutation altered the structure and function of TRMU, thereby causing mitochondrial dysfunction. Using molecular dynamics simulations, we showed that the A10S mutation introduced the Ser10 dynamic electrostatic interaction with the Lys106 residue of helix 4 within the catalytic domain of TRMU. The Western blotting analysis displayed the reduced levels of TRMU in mutant cells carrying the A10S mutation. The thermal shift assay revealed the Tm value of mutant TRMU protein, lower than that of the wild-type counterpart. The A10S mutation caused marked decreases in 2-thiouridine modification of U34 of tRNALys, tRNAGlu and tRNAGln However, the A10S mutation mildly increased the aminoacylated efficiency of tRNAs. The altered 2-thiouridine modification worsened the impairment of mitochondrial translation associated with the m.1555A→G mutation. The defective translation resulted in the reduced activities of mitochondrial respiration chains. The respiratory deficiency caused the reduction of mitochondrial ATP production and elevated the production of reactive oxidative species. As a result, mutated TRMU worsened mitochondrial dysfunctions associated with m.1555A→G mutation, exceeding the threshold for expressing a deafness phenotype. Our findings provided new insights into the pathophysiology of maternally inherited deafness that was manifested by interaction between mtDNA mutation and nuclear modifier gene.
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Affiliation(s)
- Feilong Meng
- From the Division of Medical Genetics and Genomics, Zhejiang Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,the Institute of Genetics and
| | - Xiaohui Cang
- From the Division of Medical Genetics and Genomics, Zhejiang Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,the Institute of Genetics and
| | - Yanyan Peng
- the Institute of Genetics and.,the Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Ronghua Li
- the Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30307
| | | | | | | | - Anna S Guan
- the Ahmanson Department of Pediatrics, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, California 90095, and
| | - Nathan Fischel-Ghosian
- the Ahmanson Department of Pediatrics, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, California 90095, and
| | | | - Min-Xin Guan
- From the Division of Medical Genetics and Genomics, Zhejiang Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China, .,the Institute of Genetics and.,the Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, Zhejiang 310058, China.,the Joining Institute of Genetics and Genomic Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang 310058, China
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32
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Xue L, Wang M, Li H, Wang H, Jiang F, Hou L, Geng J, Lin Z, Peng Y, Zhou H, Yu H, Jiang P, Mo JQ, Guan MX. Mitochondrial tRNA mutations in 2070 Chinese Han subjects with hypertension. Mitochondrion 2016; 30:208-21. [PMID: 27544295 DOI: 10.1016/j.mito.2016.08.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 07/21/2016] [Accepted: 08/16/2016] [Indexed: 12/28/2022]
Abstract
BACKGROUND Mitochondria have the profound impact on vascular function in both health and disease. However, mitochondrial genetic determinants for the development of hypertension remain poorly explored. METHODS AND RESULTS The Sanger sequence analysis of 22 mitochondrial tRNA genes were performed in a cohort of 2070 Han Chinese hypertensive and 512 control subjects. This analysis identified 165 variants among 22 tRNA genes. These variants were evaluated for the pathogenicity using the following criteria: (1) present in <1% of the controls; (2) evolutional conservation; (3) potential structural and functional alterations. We identified 47 (5 known and 42 novel/putative) hypertension-associated tRNA variants in 80 hypertensive subjects. These variants could have potential structural alterations and functional significance of tRNAs. By using lymphoblastoid cell lines derived from 6 probands carrying one of 6 represented variants (tRNA(Ala) 5655T>C, tRNA(Gly) 10003T>C, tRNA(Leu(UUR)) 3253T>C, tRNA(Asp) 7551A>G, tRNA(Glu) 14692A>G, tRNA(Thr) 15909A>G) and 6 control subjects lacking these variants, we showed marked reductions in the steady-state level of corresponding 5 tRNAs, but not tRNA(Thr), in mutant cell lines, compared with control cells lines. The various decreases in the activities of complexes I, III and IV were observed in mutant cells carrying one of five tRNA variants, except tRNA(Thr) 15909A>G variant. The deficient respirations were responsible for the decrease in the mitochondrial ATP production and increasing production of reactive oxygen species in mutant cell lines carrying one of five tRNA variants. CONCLUSION Mitochondrial tRNA variants are the important causes of hypertension, accounting for 3.9% cases of 2070 Han Chinese hypertensive subjects. Our findings may provide new insights into the pathophysiology of hypertension that were manifested by mitochondrial dysfunction.
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Affiliation(s)
- Ling Xue
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Meng Wang
- Institute of Genetics, Zhejiang University, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Haiying Li
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China; Department of Cardiology, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Heng Wang
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Feng Jiang
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Lingling Hou
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Junwei Geng
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhi Lin
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yanyan Peng
- Institute of Genetics, Zhejiang University, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Hong Zhou
- Institute of Genetics, Zhejiang University, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Han Yu
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Pingping Jiang
- Institute of Genetics, Zhejiang University, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jun Qin Mo
- Department of Pathology, Rady Children's Hospital, University of California San Diego School of Medicine, San Diego, CA, USA
| | - Min-Xin Guan
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang, China; Institute of Genetics, Zhejiang University, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China; Joining Institute of Genetics and Genomic Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang, China.
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33
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Wang M, Peng Y, Zheng J, Zheng B, Jin X, Liu H, Wang Y, Tang X, Huang T, Jiang P, Guan MX. A deafness-associated tRNAAsp mutation alters the m1G37 modification, aminoacylation and stability of tRNAAsp and mitochondrial function. Nucleic Acids Res 2016; 44:10974-10985. [PMID: 27536005 PMCID: PMC5159531 DOI: 10.1093/nar/gkw726] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 08/05/2016] [Indexed: 02/04/2023] Open
Abstract
In this report, we investigated the pathogenic mechanism underlying the deafness-associated mitochondrial(mt) tRNAAsp 7551A > G mutation. The m.7551A > G mutation is localized at a highly conserved nucleotide(A37), adjacent (3′) to the anticodon, which is important for the fidelity of codon recognition and stabilization in functional tRNAs. It was anticipated that the m.7551A > G mutation altered the structure and function of mt-tRNAAsp. The primer extension assay demonstrated that the m.7551A > G mutation created the m1G37 modification of mt-tRNAAsp. Using cybrid cell lines generated by transferring mitochondria from lymphoblastoid cell lines derived from a Chinese family into mitochondrial DNA(mtDNA)-less (ρo) cells, we demonstrated the significant decreases in the efficiency of aminoacylation and steady-state level of mt-tRNAAsp in mutant cybrids, compared with control cybrids. A failure in metabolism of mt-tRNAAsp caused the variable reductions in mtDNA-encoded polypeptides in mutant cybrids. Impaired mitochondrial translation led to the respiratory phenotype in mutant cybrids. The respiratory deficiency lowed mitochondrial adenosine triphosphate production and increased the production of oxidative reactive species in mutant cybrids. Our data demonstrated that mitochondrial dysfunctions caused by the m.7551A > G mutation are associated with deafness. Our findings may provide new insights into the pathophysiology of maternally transmitted deafness that was manifested by altered nucleotide modification of mitochondrial tRNA.
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Affiliation(s)
- Meng Wang
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yanyan Peng
- Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China.,Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Jing Zheng
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Binjiao Zheng
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China
| | - Xiaofen Jin
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Hao Liu
- Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yong Wang
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaowen Tang
- Attardi Institute of Mitochondrial Biomedicine, Wenzhou Medical University, Wenzhou, Zhejiang 325600, China
| | - Taosheng Huang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Pingping Jiang
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China .,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Min-Xin Guan
- Division of Clinical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China .,Institute of Genetics, Zhejiang University and Department of Genetics, Zhejiang University, School of Medicine, Hangzhou, Zhejiang 310058, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou, Zhejiang 310058, China
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Wang M, Liu H, Zheng J, Chen B, Zhou M, Fan W, Wang H, Liang X, Zhou X, Eriani G, Jiang P, Guan MX. A Deafness- and Diabetes-associated tRNA Mutation Causes Deficient Pseudouridinylation at Position 55 in tRNAGlu and Mitochondrial Dysfunction. J Biol Chem 2016; 291:21029-21041. [PMID: 27519417 DOI: 10.1074/jbc.m116.739482] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Indexed: 02/03/2023] Open
Abstract
Several mitochondrial tRNA mutations have been associated with maternally inherited diabetes and deafness. However, the pathophysiology of these tRNA mutations remains poorly understood. In this report, we identified the novel homoplasmic 14692A→G mutation in the mitochondrial tRNAGlu gene among three Han Chinese families with maternally inherited diabetes and deafness. The m.14692A→G mutation affected a highly conserved uridine at position 55 of the TΨC loop of tRNAGlu The uridine is modified to pseudouridine (Ψ55), which plays an important role in the structure and function of this tRNA. Using lymphoblastoid cell lines derived from a Chinese family, we demonstrated that the m.14692A→G mutation caused loss of Ψ55 modification and increased angiogenin-mediated endonucleolytic cleavage in mutant tRNAGlu The destabilization of base-pairing (18A-Ψ55) caused by the m.14692A→G mutation perturbed the conformation and stability of tRNAGlu An approximately 65% decrease in the steady-state level of tRNAGlu was observed in mutant cells compared with control cells. A failure in tRNAGlu metabolism impaired mitochondrial translation, especially for polypeptides with a high proportion of glutamic acid codons such as ND1, ND6, and CO2 in mutant cells. An impairment of mitochondrial translation caused defective respiratory capacity, especially reducing the activities of complexes I and IV. Furthermore, marked decreases in the levels of mitochondrial ATP and membrane potential were observed in mutant cells. These mitochondrial dysfunctions caused an increasing production of reactive oxygen species in the mutant cells. Our findings may provide new insights into the pathophysiology of maternally inherited diabetes and deafness, which is primarily manifested by the deficient nucleotide modification of mitochondrial tRNAGlu.
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Affiliation(s)
- Meng Wang
- From the Division of Clinical Genetics and Genomics, Children's Hospital and the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001
| | - Hao Liu
- the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001
| | - Jing Zheng
- From the Division of Clinical Genetics and Genomics, Children's Hospital and the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001
| | - Bobei Chen
- the Department of Otolaryngology, Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China 325035, the Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China 325035
| | - Mi Zhou
- From the Division of Clinical Genetics and Genomics, Children's Hospital and the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001
| | - Wenlu Fan
- the Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China 325035
| | - Hen Wang
- the Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China 325035
| | - Xiaoyang Liang
- From the Division of Clinical Genetics and Genomics, Children's Hospital and the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001
| | - Xiaolong Zhou
- the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China 200031, and
| | - Gilbert Eriani
- the Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, Institut de Biologie Moléculaire et Cellulaire, 15 rue René Descartes, 67084 Strasbourg, France
| | - Pingping Jiang
- From the Division of Clinical Genetics and Genomics, Children's Hospital and the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001
| | - Min-Xin Guan
- From the Division of Clinical Genetics and Genomics, Children's Hospital and the Institute of Genetics, Department of Genetics, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China 310001, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, and Joining Institute of Genetics and Genomic Medicine between Zhejiang University and University of Toronto, Zhejiang University, Hangzhou, Zhejiang, China 310058,
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35
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A Hypertension-Associated tRNAAla Mutation Alters tRNA Metabolism and Mitochondrial Function. Mol Cell Biol 2016; 36:1920-30. [PMID: 27161322 PMCID: PMC4936059 DOI: 10.1128/mcb.00199-16] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 05/04/2016] [Indexed: 01/11/2023] Open
Abstract
In this report, we investigated the pathophysiology of a novel hypertension-associated mitochondrial tRNAAla 5655A → G (m.5655A → G) mutation. The destabilization of a highly conserved base pairing (A1-U72) at the aminoacyl acceptor stem by an m.5655A → G mutation altered the tRNAAla function. An in vitro processing analysis showed that the m.5655A → G mutation reduced the efficiency of tRNAAla precursor 5′ end cleavage catalyzed by RNase P. By using cybrids constructed by transferring mitochondria from lymphoblastoid cell lines derived from a Chinese family into mitochondrial DNA (mtDNA)-less (ρo) cells, we showed a 41% reduction in the steady-state level of tRNAAla in mutant cybrids. The mutation caused an improperly aminoacylated tRNAAla, as suggested by aberrantly aminoacylated tRNAAla and slower electrophoretic mobility of mutated tRNA. A failure in tRNAAla metabolism contributed to variable reductions in six mtDNA-encoded polypeptides in mutant cells, ranging from 21% to 37.5%, with an average of a 29.1% reduction, compared to levels of the controls. The impaired translation caused reduced activities of mitochondrial respiration chains. Furthermore, marked decreases in the levels of mitochondrial ATP and membrane potential were observed in mutant cells. These caused increases in the production of reactive oxygen species in the mutant cybrids. The data provide evidence for the association of the tRNAAla 5655A → G mutation with hypertension.
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36
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Mutational screening in patients with profound sensorineural hearing loss and neurodevelopmental delay: Description of a novel m.3861A > C mitochondrial mutation in the MT-ND1 gene. Biochem Biophys Res Commun 2016; 474:702-708. [PMID: 27155156 DOI: 10.1016/j.bbrc.2016.05.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 05/03/2016] [Indexed: 11/22/2022]
Abstract
Mitochondrial diseases caused by mitochondrial dysfunction are a clinically and genetically, heterogeneous group of disorders involving multiple organs, particularly tissues with high-energy demand. Hearing loss is a recognized symptom of a number of mitochondrial diseases and can result from neuronal or cochlear dysfunction. The tissue affected in this pathology is most probably the cochlear hair cells, which are essential for hearing function since they are responsible for maintaining the ionic gradients necessary for sound signal transduction. Several mitochondrial DNA mutations have been associated with hearing loss and since mitochondria are crucial for the cellular energy supply in many tissues, most of these mtDNA mutations affect several tissues and will cause syndromic hearing loss. In the present study, we described 2 patients with sensorineural hearing loss and neurodevelopmental delay in whom we tested mitochondrial genes described to be associated with syndromic hearing loss. One of these patients showed a novel heteroplasmic mitochondrial mutation m.3861A > C (W185C) which lead to a loss of stability of the ND1 protein since it created a new hydrogen bund between the unique created cystein C185 and the A182 residue. In the second patient, we detected two novel heteroplasmic variations m.12350C > A (T5N) and m.14351T > C (E108G) respectively in the MT-ND5 and the MT-ND6 genes. The TopPred II prediction for the E108G variation revealed a decrease of the hydrophobicity in the mutated MT-ND6.
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Kozhukhar N, Spadafora D, Fayzulin R, Shokolenko IN, Alexeyev M. The efficiency of the translesion synthesis across abasic sites by mitochondrial DNA polymerase is low in mitochondria of 3T3 cells. Mitochondrial DNA A DNA Mapp Seq Anal 2015; 27:4390-4396. [PMID: 26470640 DOI: 10.3109/19401736.2015.1089539] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Translesion synthesis by specialized DNA polymerases is an important strategy for mitigating DNA damage that cannot be otherwise repaired either due to the chemical nature of the lesion. Apurinic/Apyrimidinic (abasic, AP) sites represent a block to both transcription and replication, and are normally repaired by the base excision repair (BER) pathway. However, when the number of abasic sites exceeds BER capacity, mitochondrial DNA is targeted for degradation. Here, we used two uracil-N-glycosylase (UNG1) mutants, Y147A or N204D, to generate AP sites directly in the mtDNA of NIH3T3 cells in vivo at sites normally occupied by T or C residues, respectively, and to study repair of these lesions in their native context. We conclude that mitochondrial DNA polymerase γ (Pol γ) is capable of translesion synthesis across AP sites in mitochondria of the NIH3T3 cells, and obeys the A-rule. However, in our system, base excision repair (BER) and mtDNA degradation occur more frequently than translesion bypass of AP sites.
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Affiliation(s)
- Natalya Kozhukhar
- a Department of Physiology and Cell Biology , University of South Alabama , Mobile , AL , USA
| | - Domenico Spadafora
- b Department of Pharmacology , University of South Alabama , Mobile , AL , USA and
| | - Rafik Fayzulin
- a Department of Physiology and Cell Biology , University of South Alabama , Mobile , AL , USA
| | - Inna N Shokolenko
- c Department of Biomedical Sciences , University of South Alabama, Patt Capps Covey College of Allied Health Professions , Mobile , AL , USA
| | - Mikhail Alexeyev
- a Department of Physiology and Cell Biology , University of South Alabama , Mobile , AL , USA
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38
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Reverendo M, Soares AR, Pereira PM, Carreto L, Ferreira V, Gatti E, Pierre P, Moura GR, Santos MA. TRNA mutations that affect decoding fidelity deregulate development and the proteostasis network in zebrafish. RNA Biol 2015; 11:1199-213. [PMID: 25483040 DOI: 10.4161/rna.32199] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Mutations in genes that encode tRNAs, aminoacyl-tRNA syntheases, tRNA modifying enzymes and other tRNA interacting partners are associated with neuropathies, cancer, type-II diabetes and hearing loss, but how these mutations cause disease is unclear. We have hypothesized that levels of tRNA decoding error (mistranslation) that do not fully impair embryonic development can accelerate cell degeneration through proteome instability and saturation of the proteostasis network. To test this hypothesis we have induced mistranslation in zebrafish embryos using mutant tRNAs that misincorporate Serine (Ser) at various non-cognate codon sites. Embryo viability was affected and malformations were observed, but a significant proportion of embryos survived by activating the unfolded protein response (UPR), the ubiquitin proteasome pathway (UPP) and downregulating protein biosynthesis. Accumulation of reactive oxygen species (ROS), mitochondrial and nuclear DNA damage and disruption of the mitochondrial network, were also observed, suggesting that mistranslation had a strong negative impact on protein synthesis rate, ER and mitochondrial homeostasis. We postulate that mistranslation promotes gradual cellular degeneration and disease through protein aggregation, mitochondrial dysfunction and genome instability.
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Tang X, Zheng J, Ying Z, Cai Z, Gao Y, He Z, Yu H, Yao J, Yang Y, Wang H, Chen Y, Guan MX. Mitochondrial tRNA(Ser(UCN)) variants in 2651 Han Chinese subjects with hearing loss. Mitochondrion 2015; 23:17-24. [PMID: 25968158 DOI: 10.1016/j.mito.2015.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 04/14/2015] [Accepted: 05/04/2015] [Indexed: 12/17/2022]
Abstract
Mutations in the mitochondrial DNA have been associated with hearing loss. However, the prevalence and spectrum of mitochondrial tRNA mutations in hearing-impaired subjects are poorly understood. In this report, we have investigated the prevalence and spectrum of mitochondrial tRNA(Ser(UCN)) mutations in a large cohort of 2651 Han Chinese subjects with hearing loss. The clinical evaluation showed that 744 subjects (432 males and 312 females) had a history of exposure to aminoglycosides and other probands exhibited nonsyndromic hearing loss. Mutational analysis of tRNA(Ser(UCN)) gene identified 9 (8 known and 1 novel) variants. The prevalence of the known deafness-associated 7511T>C, 7505T>C and 7445A>C mutations was 0.04%, 0.04% and 0.04%, respectively. Other variants were evaluated by the evolutionary conservation, allelic frequency of Chinese controls, potential structural and functional alterations and pedigree analysis. Three variants were polymorphisms, while the 7444G>A, 7471DelG and 7496A>G variants were putative deafness-associated mutations. These putative deafness-associated variants accounted for 0.68% cases of hearing-impaired subjects in this cohort. The low penetrance of hearing loss in pedigrees carrying one of these putative deafness-associated mutations indicated that the mutation(s) is necessary but itself insufficient to produce a clinical phenotype. Other genetic or environmental factor(s) may influence the phenotypic manifestation of these tRNA(Ser(UCN)) mutations. Moreover, mtDNAs in 20 probands carrying one of the putative deafness-associated mutations were widely dispersed among 8 Eastern Asian haplogroups. In particular, the occurrences of haplogroups D4a, M22, and H2 in patients carrying the deafness-associated variants were higher than those in Chinese controls. These data further support that the mitochondrial tRNA(Ser(UCN)) gene is the hot spot for mutations associated with hearing loss. Thus, our findings may provide valuable information for the further understanding of pathophysiology and management of hearing loss.
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Affiliation(s)
- Xiaowen Tang
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jing Zheng
- Institute of Genetics, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zhengbiao Ying
- Department of Otolaryngology, Wenling People's Hospital, Wenzhou Medical University, Wenling, Zhejiang, China
| | - Zhaoyang Cai
- Department of Otolaryngology, Wenling People's Hospital, Wenzhou Medical University, Wenling, Zhejiang, China
| | - Yinglong Gao
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zheyun He
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Han Yu
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Juan Yao
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yaling Yang
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Hui Wang
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Ye Chen
- Institute of Genetics, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Min-Xin Guan
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, China; Institute of Genetics, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
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Scheffler IE. Mitochondrial disease associated with complex I (NADH-CoQ oxidoreductase) deficiency. J Inherit Metab Dis 2015; 38:405-15. [PMID: 25224827 DOI: 10.1007/s10545-014-9768-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 08/27/2014] [Accepted: 09/02/2014] [Indexed: 01/09/2023]
Abstract
Mitochondrial diseases due to a reduced capacity for oxidative phosphorylation were first identified more than 20 years ago, and their incidence is now recognized to be quite significant. In a large proportion of cases the problem can be traced to a complex I (NADH-CoQ oxidoreductase) deficiency (Phenotype MIM #252010). Because the complex consists of 44 subunits, there are many potential targets for pathogenic mutations, both on the nuclear and mitochondrial genomes. Surprisingly, however, almost half of the complex I deficiencies are due to defects in as yet unidentified genes that encode proteins other than the structural proteins of the complex. This review attempts to summarize what we know about the molecular basis of complex I deficiencies: mutations in the known structural genes, and mutations in an increasing number of genes encoding "assembly factors", that is, proteins required for the biogenesis of a functional complex I that are not found in the final complex I. More such genes must be identified before definitive genetic counselling can be applied in all cases of affected families.
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Affiliation(s)
- Immo E Scheffler
- Division of Biology (Molecular Biology Section), University of California San Diego, 9500 Gilman Dr., La Jolla, CA, 92093-0322, USA,
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41
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Horiguchi T, Fuka M, Fujisawa K, Tanimura A, Miyoshi K, Murakami R, Noma T. Adenylate kinase 2 deficiency limits survival and regulates various genes during larval stages of Drosophila melanogaster. THE JOURNAL OF MEDICAL INVESTIGATION 2015; 61:137-50. [PMID: 24705759 DOI: 10.2152/jmi.61.137] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Adenylate kinase isozyme 2 (AK2) is located in mitochondrial intermembrane space and regulates energy metabolism by reversibly converting ATP and AMP to 2 ADPs. We previously demonstrated that disruption of the Drosophila melanogaster AK2 gene (Dak2) resulted in growth arrest during the larval stage and subsequent death. Two other groups found that human AK2 mutations cause reticular dysgenesis, a form of severe combined immunodeficiency (SCID) that is associated with severe hematopoietic defects and sensorineural deafness. However, the mechanisms underlying differential outcomes of AK2 deficiency in Drosophila and human systems remain unknown. In this study, effects of tissue-specific inactivation of the Dak2 gene on Drosophila development were analyzed using RNAi-mediated gene knockdown. In addition, to investigate the roles of AK2 in the regulation of gene expression during development, microarray analysis was performed using RNA from first and second instar larvae of Dak2-deficient mutant and wild-type D. melanogaster. Knockdown of Dak2 in all germ layers caused cessation of growth and subsequent death of flies. Microarray analysis revealed that Dak2 deficiency downregulates various genes, particularly those involved in the proteasomal function and in mitochondrial translation machinery. These data indicate that adenine nucleotide interconversion by Dak2 is crucial for developmental processes of Drosophila melanogaster.
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Affiliation(s)
- Taigo Horiguchi
- Department of Molecular Biology, Institute of Health Biosciences, the University of Tokushima Graduate School
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42
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Fayzulin RZ, Perez M, Kozhukhar N, Spadafora D, Wilson GL, Alexeyev MF. A method for mutagenesis of mouse mtDNA and a resource of mouse mtDNA mutations for modeling human pathological conditions. Nucleic Acids Res 2015; 43:e62. [PMID: 25820427 PMCID: PMC4482060 DOI: 10.1093/nar/gkv140] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 02/10/2015] [Indexed: 12/23/2022] Open
Abstract
Mutations in human mitochondrial DNA (mtDNA) can cause mitochondrial disease and have been associated with neurodegenerative disorders, cancer, diabetes and aging. Yet our progress toward delineating the precise contributions of mtDNA mutations to these conditions is impeded by the limited availability of faithful transmitochondrial animal models. Here, we report a method for the isolation of mutations in mouse mtDNA and its implementation for the generation of a collection of over 150 cell lines suitable for the production of transmitochondrial mice. This method is based on the limited mutagenesis of mtDNA by proofreading-deficient DNA-polymerase γ followed by segregation of the resulting highly heteroplasmic mtDNA population by means of intracellular cloning. Among generated cell lines, we identify nine which carry mutations affecting the same amino acid or nucleotide positions as in human disease, including a mutation in the ND4 gene responsible for 70% of Leber Hereditary Optic Neuropathies (LHON). Similar to their human counterparts, cybrids carrying the homoplasmic mouse LHON mutation demonstrated reduced respiration, reduced ATP content and elevated production of mitochondrial reactive oxygen species (ROS). The generated resource of mouse mtDNA mutants will be useful both in modeling human mitochondrial disease and in understanding the mechanisms of ROS production mediated by mutations in mtDNA.
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Affiliation(s)
- Rafik Z Fayzulin
- Department of Cell Biology and Neuroscience, University of South Alabama, Mobile, AL 36688, USA
| | - Michael Perez
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Natalia Kozhukhar
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Domenico Spadafora
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Glenn L Wilson
- Department of Cell Biology and Neuroscience, University of South Alabama, Mobile, AL 36688, USA
| | - Mikhail F Alexeyev
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL 36688, USA
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43
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Luo Z. Mitochondrial tRNAArg T10454C variant may not influence the clinical expression of deafness associated 12S rRNA A1555G mutation. Mitochondrial DNA A DNA Mapp Seq Anal 2014; 27:1137-40. [PMID: 24983150 DOI: 10.3109/19401736.2014.933337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In this study, we examined the "pathogenic" role of the T10454C mutation in mitochondrial tRNA(Arg) gene in deafness expression as increasing reports provided an active role of this mutation in clinical manifestation of deafness associated 12S rRNA A1555G mutation. For this purpose, we reanalyzed the complete mitochondrial DNA (mtDNA) sequence data containing the T10454C mutation. Moreover, we analyzed the reported "polymorphisms" of mtDNA in the proband using the phylogentic approach. To our surprise, other mutations which occurred at protein-coding genes played more important roles in resulting mitochondrial dysfunctions by using the bioinformatic tool. In addition, evolutionary conservation analysis of the T10454C mutation indicated that this mutation was not conserved between different species. To our knowledge, this is the first report that the T10454C variant may not modulate the phenotypic expression of the deafness associated A1555G mutation.
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Affiliation(s)
- Zhiyi Luo
- a Department of the Emergency Center , The First Affiliated Hospital of Zhengzhou University , Zhengzhou , China
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44
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Gong S, Peng Y, Jiang P, Wang M, Fan M, Wang X, Zhou H, Li H, Yan Q, Huang T, Guan MX. A deafness-associated tRNAHis mutation alters the mitochondrial function, ROS production and membrane potential. Nucleic Acids Res 2014; 42:8039-48. [PMID: 24920829 PMCID: PMC4081083 DOI: 10.1093/nar/gku466] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In this report, we investigated the molecular genetic mechanism underlying the deafness-associated mitochondrial tRNAHis 12201T>C mutation. The destabilization of a highly conserved base-pairing (5A-68U) by the m.12201T>C mutation alters structure and function of tRNAHis. Using cybrids constructed by transferring mitochondria from lymphoblastoid cell lines derived from a Chinese family into mtDNA-less (ρo) cells, we showed ∼70% decrease in the steady-state level of tRNAHis in mutant cybrids, compared with control cybrids. The mutation changed the conformation of tRNAHis, as suggested by slower electrophoretic mobility of mutated tRNA with respect to the wild-type molecule. However, ∼60% increase in aminoacylated level of tRNAHis was observed in mutant cells. The failure in tRNAHis metabolism was responsible for the variable reductions in seven mtDNA-encoded polypeptides in mutant cells, ranging from 37 to 81%, with the average of ∼46% reduction, as compared with those of control cells. The impaired mitochondrial translation caused defects in respiratory capacity in mutant cells. Furthermore, marked decreases in the levels of mitochondrial ATP and membrane potential were observed in mutant cells. These mitochondrial dysfunctions caused an increase in the production of reactive oxygen species in the mutant cells. The data provide the evidence for a mitochondrial tRNAHis mutation leading to deafness.
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Affiliation(s)
- Shasha Gong
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058
| | - Yanyan Peng
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058 Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA 45229
| | - Pingping Jiang
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058
| | - Meng Wang
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058
| | - Mingjie Fan
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058
| | - Xinjian Wang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA 45229
| | - Hong Zhou
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058
| | - Huawei Li
- Department of Otology and Skull Base Surgery, Eye and ENT Hospital, Fudan University, Shanghai, China 200031
| | - Qingfeng Yan
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058
| | - Taosheng Huang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA 45229
| | - Min-Xin Guan
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang, China 310058 Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA 45229
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45
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Kabekkodu SP, Bhat S, Mascarenhas R, Mallya S, Bhat M, Pandey D, Kushtagi P, Thangaraj K, Gopinath P, Satyamoorthy K. Mitochondrial DNA variation analysis in cervical cancer. Mitochondrion 2014; 16:73-82. [PMID: 23851045 DOI: 10.1016/j.mito.2013.07.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/15/2013] [Accepted: 07/01/2013] [Indexed: 01/01/2023]
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46
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Shokolenko IN, Wilson GL, Alexeyev MF. The "fast" and the "slow" modes of mitochondrial DNA degradation. Mitochondrial DNA A DNA Mapp Seq Anal 2014; 27:490-8. [PMID: 24724936 DOI: 10.3109/19401736.2014.905829] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In a living cell, oxidative stress resulting from an external or internal insult can result in mitochondrial DNA (mtDNA) damage and degradation. Here, we show that in HeLa cells, mtDNA can withstand relatively high levels of extracellular oxidant H2O2 before it is damaged to a point of degradation, and that mtDNA levels in these cells quickly recover after removal of the stressor. In contrast, mtDNA degradation in mouse fibroblast cells is induced at eight-fold lower concentrations of H2O2, and restoration of the lost mtDNA proceeds much slower. Importantly, mtDNA levels in HeLa cells continue to decline even after withdrawal of the stressor thus marking the "slow" mode of mtDNA degradation. Conversely, in mouse fibroblasts maximal loss of mtDNA is achieved during treatment, and is already detectable at 5 min after exposure, indicating the "fast" mode. These differences may modulate susceptibility to oxidative stress of those organs, which consist of multiple cell types.
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Affiliation(s)
- Inna N Shokolenko
- a Department of Cell Biology and Neuroscience , University of South Alabama , Mobile , AL , USA
| | - Glenn L Wilson
- a Department of Cell Biology and Neuroscience , University of South Alabama , Mobile , AL , USA
| | - Mikhail F Alexeyev
- a Department of Cell Biology and Neuroscience , University of South Alabama , Mobile , AL , USA
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47
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Zhu Q, Zhou Y, Jin X, Lin X. The role of mitochondrial tRNAPhe C628T variant in deafness expression. ACTA ACUST UNITED AC 2013; 26:2-6. [PMID: 24021014 DOI: 10.3109/19401736.2013.823192] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mutations in mitochondrial genome are one of the most important causes of hearing loss, of these, mitochondrial tRNA (mt-tRNA) genes are the hot spots for mutations associated with deafness. Most recently, a novel mt-tRNA(Phe) C628T variant has been reported to be associated with non-syndromic and sensorineural hearing loss. To test this association, we characterized the C628T variant using a phylogenetic approach; in addition, we employed the bioinformatics tool to predict the thermodynamic change of the mt-tRNA(Phe) gene with and without this variant. Intriguingly, the C628T variant was not evolutionary conserved and had little effect on mt-tRNA(Phe) folding. Moreover, through the application of the pathogenicity scoring system, we classified the C628T variant as a "neutral polymorphism", suggesting that this variant currently lacked sufficient evident to support as a "pathogenic" mutation.
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Affiliation(s)
- Qingzhang Zhu
- Taizhou Hospital of Zhejiang Province, Wenzhou Medical University , Linhai , People's Republic of China
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48
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Guaran V, Astolfi L, Castiglione A, Simoni E, Olivetto E, Galasso M, Trevisi P, Busi M, Volinia S, Martini A. Association between idiopathic hearing loss and mitochondrial DNA mutations: a study on 169 hearing-impaired subjects. Int J Mol Med 2013; 32:785-94. [PMID: 23969527 PMCID: PMC3812239 DOI: 10.3892/ijmm.2013.1470] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/24/2013] [Indexed: 11/16/2022] Open
Abstract
Mutations in mitochondrial DNA (mtDNA) have been shown to be an important cause of sensorineural hearing loss (SNHL). In this study, we performed a clinical and genetic analysis of 169 hearing-impaired patients and some of their relatives suffering from idiopathic SNHL, both familial and sporadic. The analysis of four fragments of their mtDNA identified several polymorphisms, the well known pathogenic mutation, A1555G, and some novel mutations in different genes, implying changes in the aminoacidic sequence. A novel sporadic mutation in 12S rRNA (MT-RNR1), not previously reported in the literature, was found in a case of possible aminoglycoside-induced progressive deafness.
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Affiliation(s)
- Valeria Guaran
- Bioacoustics Research Laboratory, Department of Neurosciences, University of Padua, I-35129 Padua, Italy.
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49
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Mkaouar-Rebai E, Ben Mahmoud A, Chamkha I, Chabchoub I, Kammoun T, Hachicha M, Fakhfakh F. A novel MT-CO2 m.8249G > A pathogenic variation and the MT-TW m.5521G > A mutation in patients with mitochondrial myopathy. ACTA ACUST UNITED AC 2013; 25:394-9. [DOI: 10.3109/19401736.2013.803086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Emna Mkaouar-Rebai
- Laboratory of Human Molecular Genetics, Faculty of Medicine, University of SfaxTunisia
| | - Afif Ben Mahmoud
- Laboratory of Human Molecular Genetics, Faculty of Medicine, University of SfaxTunisia
| | - Imen Chamkha
- Laboratory of Human Molecular Genetics, Faculty of Medicine, University of SfaxTunisia
| | - Imen Chabchoub
- Service de Pédiatrie, C.H.U. Habib Bourguiba de SfaxTunisia
| | | | | | - Faiza Fakhfakh
- Laboratory of Human Molecular Genetics, Faculty of Medicine, University of SfaxTunisia
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50
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Shokolenko IN, Wilson GL, Alexeyev MF. Persistent damage induces mitochondrial DNA degradation. DNA Repair (Amst) 2013; 12:488-99. [PMID: 23721969 PMCID: PMC3683391 DOI: 10.1016/j.dnarep.2013.04.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 03/20/2013] [Accepted: 04/22/2013] [Indexed: 01/12/2023]
Abstract
Considerable progress has been made recently toward understanding the processes of mitochondrial DNA (mtDNA) damage and repair. However, a paucity of information still exists regarding the physiological effects of persistent mtDNA damage. This is due, in part, to experimental difficulties associated with targeting mtDNA for damage, while sparing nuclear DNA. Here, we characterize two systems designed for targeted mtDNA damage based on the inducible (Tet-ON) mitochondrial expression of the bacterial enzyme, exonuclease III, and the human enzyme, uracil-N-glyosylase containing the Y147A mutation. In both systems, damage was accompanied by degradation of mtDNA, which was detectable by 6h after induction of mutant uracil-N-glycosylase and by 12h after induction of exoIII. Unexpectedly, increases in the steady-state levels of single-strand lesions, which led to degradation, were small in absolute terms indicating that both abasic sites and single-strand gaps may be poorly tolerated in mtDNA. mtDNA degradation was accompanied by the loss of expression of mtDNA-encoded COX2. After withdrawal of the inducer, recovery from mtDNA depletion occurred faster in the system expressing exonuclease III, but in both systems reduced mtDNA levels persisted longer than 144h after doxycycline withdrawal. mtDNA degradation was followed by reduction and loss of respiration, decreased membrane potential, reduced cell viability, reduced intrinsic reactive oxygen species production, slowed proliferation, and changes in mitochondrial morphology (fragmentation of the mitochondrial network, rounding and "foaming" of the mitochondria). The mutagenic effects of abasic sites in mtDNA were low, which indicates that damaged mtDNA molecules may be degraded if not rapidly repaired. This study establishes, for the first time, that mtDNA degradation can be a direct and immediate consequence of persistent mtDNA damage and that increased ROS production is not an invariant consequence of mtDNA damage.
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Affiliation(s)
- Inna N. Shokolenko
- Department of Cell Biology and Neuroscience, University of South Alabama, Mobile, AL (USA) 36688. Tel (251) 460-6772, Fax (251) 460-6771
| | - Glenn L. Wilson
- Department of Cell Biology and Neuroscience, University of South Alabama, Mobile, AL (USA) 36688. Tel (251) 460-6765, Fax (251) 460-6771
| | - Mikhail F. Alexeyev
- Department of Cell Biology and Neuroscience, University of South Alabama, Mobile, AL (USA) 36688
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