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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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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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Wu EY, Landry L. Conserved spatiotemporal expression landscape of dominant tRNA genes in human and mouse. Biochem Biophys Res Commun 2023; 681:173-179. [PMID: 37776749 DOI: 10.1016/j.bbrc.2023.09.054] [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: 08/29/2023] [Accepted: 09/20/2023] [Indexed: 10/02/2023]
Abstract
Transfer RNAs are integral for protein synthesis and the interpretation of the information contained in DNA. To date, a few methods, including custom microarrays and custom targeted sequencing, have been used to quantify tRNA. However, methods using available RNA-sequencing data have not yet been reported. We created a bioinformatics pipeline to quantify the highly expressed tRNAs in RNA-Seq effectively, demonstrated by the preserved ratio of the expression levels of two massively duplicated tRNAAla genes in mouse. Using this quantification, we examined the tRNA expression with relation to tissue type and developmental stage in both human and mouse. Heart exhibited the highest overall tRNA expression for both human and mouse. Furthermore, tRNA expression grew to a peak before decreasing steadily with developmental stage, a trend that was conserved in both human and mouse. The two mitochondrial tRNA genes, tRNASer(TCA)(m) and tRNALeu(TTA)(m), which partly contribute to these trends, have been attributed to various human diseases. The tissue-specific high expression of tRNAGln(CAG) and tRNAGln(CAA) in human brains, especially in hindbrain and cerebellum, suggests their important roles in neurological disorders. In summary, our approach revealed conserved spatiotemporal expression of highly expressed tRNAs in both human and mouse. Our method can be applied to other RNA-Seq data to examine the roles of these tRNAs in different human diseases or scientific studies.
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Affiliation(s)
- Evan Y Wu
- Memphis University School, 6191 Park Ave, Memphis, TN, 38119, USA.
| | - Laura Landry
- Memphis University School, 6191 Park Ave, Memphis, TN, 38119, USA.
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4
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Ding H, Zhao Y, Jiang Z, Zhou D, Zhu R. Analysis of Mitochondrial Transfer RNA Mutations in Breast Cancer. Balkan J Med Genet 2023; 25:15-22. [PMID: 37265965 PMCID: PMC10230833 DOI: 10.2478/bjmg-2022-0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023] Open
Abstract
Damage of mitochondrial functions caused by mitochondrial DNA (mtDNA) pathogenic mutations had long been proposed to be involved in breast carcinogenesis. However, the detailed pathological mechanism remained deeply undetermined. In this case-control study, we screened the frequencies of mitochondrial tRNA (mt-tRNA) mutations in 80 breast cancer tissues and matched normal adjacent tissues. PCR and Sanger sequence revealed five possible pathogenic mutations: tRNAVal G1606A, tRNAIle A4300G, tRNASer(UCN) T7505C, tRNAGlu A14693G and tRNAThr G15927A. We noticed that these mutations resided at extremely conserved positions of tRNAs and would affect tRNAs transcription or modifications. Furthermore, functional analysis suggested that patients with these mt-tRNA mutations exhibited much lower levels of mtDNA copy number and ATP, as compared with controls (p<0.05). Therefore, it can be speculated that these mutations may impair mitochondrial protein synthesis and oxidative phosphorylation (OXPHOS) complexes, which caused mitochondrial dysfunctions that were involved in the breast carcinogenesis. Taken together, our data indicated that mutations in mt-tRNA were the important contributors to breast cancer, and mutational analyses of mt-tRNA genes were critical for prevention of breast cancer.
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Affiliation(s)
- H.J. Ding
- School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Y.P. Zhao
- Department of Pharmacy, Shaoxing Hospital of Traditional Chinese Medicine Affiliated to Zhejiang Chinese Medical University, Shaoxing, China
| | - Z.C. Jiang
- Department of Pathology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - D.T. Zhou
- Department of Pharmacy, The First People’s Hospital of Kaili, Kaili, China
| | - R. Zhu
- School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
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5
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Jin P, Wang Y, Nian N, Wang GQ, Fu XM. Hereditary spastic paraplegia (SPG 48) with deafness and azoospermia: A case report. Front Neurol 2023; 14:1156100. [PMID: 37077568 PMCID: PMC10106626 DOI: 10.3389/fneur.2023.1156100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/21/2023] [Indexed: 04/05/2023] Open
Abstract
Hereditary spastic paraplegias (HSP) are inherited neurodegenerative disorders characterized by progressive paraplegia and spasticity in the lower limbs. SPG48 represents a rare genotype characterized by mutations in AP5Z1, a gene playing a role in intracellular membrane trafficking. This study describes a case of a 53-year-old male patient with SPG48 presenting spastic paraplegia, infertility, hearing impairment, cognitive abnormalities and peripheral neuropathy. The Sanger sequencing revealed a homozygous deletion in the chr 7:4785904-4786677 region causing a premature stop codon in exon 10. The patient's brother was heterozygous for the mutation. The brain magnetic resonance imaging found a mild brain atrophy and white matter lesions. In the analysis of the auditory thresholds, we found a significant hearing decrease in both ears.
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Affiliation(s)
- Ping Jin
- Department of Neurology, The Affiliated Hospital of Institute of Neurology, Anhui University of Chinese Medicine, Hefei, China
| | - Yu Wang
- Department of Neurology, The Affiliated Hospital of Institute of Neurology, Anhui University of Chinese Medicine, Hefei, China
| | - Na Nian
- Department of Neurology, The Affiliated Hospital of Institute of Neurology, Anhui University of Chinese Medicine, Hefei, China
| | - Gong-Qiang Wang
- Department of Neurology, The Affiliated Hospital of Institute of Neurology, Anhui University of Chinese Medicine, Hefei, China
| | - Xiao-Ming Fu
- Department of Neurology, The Affiliated Hospital of Institute of Neurology, Anhui University of Chinese Medicine, Hefei, China
- Institute of Neurology, Anhui University of Chinese, Hefei, China
- *Correspondence: Xiao-Ming Fu
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Shaukat AN, Kaliatsi EG, Stamatopoulou V, Stathopoulos C. Mitochondrial tRNA-Derived Fragments and Their Contribution to Gene Expression Regulation. Front Physiol 2021; 12:729452. [PMID: 34539450 PMCID: PMC8446549 DOI: 10.3389/fphys.2021.729452] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 08/09/2021] [Indexed: 01/14/2023] Open
Abstract
Mutations in human mitochondrial tRNAs (mt-tRNAs) are responsible for several and sometimes severe clinical phenotypes, classified among mitochondrial diseases. In addition, post-transcriptional modifications of mt-tRNAs in correlation with several stress signals can affect their stability similarly to what has been described for their nuclear-encoded counterparts. Many of the perturbations related to either point mutations or aberrant modifications of mt-tRNAs can lead to specific cleavage and the production of mitochondrial tRNA-derived fragments (mt-tRFs). Although mt-tRFs have been detected in several studies, the exact biogenesis steps and biological role remain, to a great extent, unexplored. Several mt-tRFs are produced because of the excessive oxidative stress which predominantly affects mitochondrial DNA integrity. In addition, mt-tRFs have been detected in various diseases with possible detrimental consequences, but also their production may represent a response mechanism to external stimuli, including infections from pathogens. Finally, specific point mutations on mt-tRNAs have been reported to impact the pool of the produced mt-tRFs and there is growing evidence suggesting that mt-tRFs can be exported and act in the cytoplasm. In this review, we summarize current knowledge on mitochondrial tRNA-deriving fragments and their possible contribution to gene expression regulation.
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Affiliation(s)
| | - Eleni G Kaliatsi
- Department of Biochemistry, School of Medicine, University of Patras, Patras, Greece
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Abstract
Mitochondrial dysfunction has been suggested to be a risk factor for sensorineural hearing loss (SNHL) induced by aging, noise, ototoxic drugs, and gene. Reactive oxygen species (ROS) are mainly derived from mitochondria, and oxidative stress induced by ROS contributes to cochlear damage as well as mitochondrial DNA mutations, which may enhance the sensitivity and severity of hearing loss and disrupt ion homeostasis (e.g., Ca2+ homeostasis). The formation and accumulation of ROS further undermine mitochondrial components and ultimately lead to apoptosis and necrosis. SIRT3–5, located in mitochondria, belong to the family of sirtuins, which are highly conserved deacetylases dependent on nicotinamide adenine dinucleotide (NAD+). These deacetylases regulate diverse cellular biochemical activities. Recent studies have revealed that mitochondrial sirtuins, especially SIRT3, modulate ROS levels in hearing loss pathologies. Although the precise functions of SIRT4 and SIRT5 in the cochlea remain unclear, the molecular mechanisms in other tissues indicate a potential protective effect against hearing loss. In this review, we summarize the current knowledge regarding the role of mitochondrial dysfunction in hearing loss, discuss possible functional links between mitochondrial sirtuins and SNHL, and propose a perspective that SIRT3–5 have a positive effect on SNHL.
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A mitochondrial myopathy-associated tRNA Ser(UCN) 7453G>A mutation alters tRNA metabolism and mitochondrial function. Mitochondrion 2020; 57:1-8. [PMID: 33279600 DOI: 10.1016/j.mito.2020.11.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 10/09/2020] [Accepted: 11/23/2020] [Indexed: 12/25/2022]
Abstract
BACKGROUND Mitochondrial disorders are a group of heterogeneous diseases characterized by biochemical disturbances in oxidative phosphorylation (OXPHOS). Mutations in mitochondrial transfer RNA (mt-tRNA) genes are the most frequently in mitochondrial disease. However, few studies have detailed the molecular mechanisms behind these mutations. METHODS We performed clinical evaluation, genetic analysis, muscle histochemistry, and molecular and biochemical investigations in muscle tissue and proband-derived cybrid cell lines. RESULTS We found a mitochondrial tRNASer(UCN) mutation (m.7453G>A) in a 15-year-old patient with severe mitochondrial myopathy. We demonstrated that this mutation caused impairment of mitochondrial translation, respiratory deficiency, overproduction of reactive oxygen species (ROS), and decreased mitochondrial membrane potential (MMP), which ultimately led to severe mitochondrial myopathy. CONCLUSION Our findings offer valuable new insights into the tRNASer(UCN) m.7453G>A mutation for both the pathogenic mechanism and functional consequences.
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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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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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11
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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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