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Ghirigato E, Terenzi F, Baglivo M, Zanetti N, Baldo F, Murru FM, Bobbo M, Barbi E, Zeviani M, Bruno I, Lamantea E. A new family with a case of severe early-onset muscle fatigue and a peculiar maternally inherited painful swelling in chewing muscles associated with homoplasmic m.15992A>T mutation in mitochondrial tRNAPro. Neuromuscul Disord 2023; 33:972-977. [PMID: 38030461 DOI: 10.1016/j.nmd.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 09/12/2023] [Accepted: 11/01/2023] [Indexed: 12/01/2023]
Abstract
A 16-year-old boy was evaluated for a history of exercise-induced fatigability associated with nausea even after minimal effort, lower limbs muscle hypotrophy, and swelling of the masseter muscles after chewing. Laboratory tests were remarkable for hyperlactatemia and metabolic acidosis after short physical activity. The muscle biopsy showed non-specific mitochondrial alterations and an increase in intrafibral lipids. Biochemical analysis showed reduced activity of the respiratory chain complexes. Mitochondrial DNA sequencing revealed the presence of a homoplasmic variant m.15992A>T in the MT-TP gene, coding for the mt-tRNAPro in the patient, in his mother and in his brother. Pathogenic or likely pathogenic variants in MT-TP gene are rare. They are responsible for different clinical presentation, almost ever involving the muscle tissue. We report the first family with exercise-induced muscle weakness and swelling of the chewing muscles due to m.15992A>T variant in absence of J1c10 haplogroup, confirming its pathogenicity.
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Affiliation(s)
| | | | - Mirko Baglivo
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Nadia Zanetti
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Francesco Baldo
- Institute for Maternal and Child Health IRCCS Burlo Garofolo, Trieste, Italy.
| | - Flora Maria Murru
- Institute for Maternal and Child Health IRCCS Burlo Garofolo, Trieste, Italy
| | - Marco Bobbo
- Institute for Maternal and Child Health IRCCS Burlo Garofolo, Trieste, Italy
| | - Egidio Barbi
- University of Trieste, Italy; Institute for Maternal and Child Health IRCCS Burlo Garofolo, Trieste, Italy
| | - Massimo Zeviani
- Institute for Maternal and Child Health IRCCS Burlo Garofolo, Trieste, Italy
| | - Irene Bruno
- Institute for Maternal and Child Health IRCCS Burlo Garofolo, Trieste, Italy
| | - Eleonora Lamantea
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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2
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Kong LY, Wu YZ, Cheng RQ, Wang PH, Peng BW. Role of Mutations of Mitochondrial Aminoacyl-tRNA Synthetases Genes on Epileptogenesis. Mol Neurobiol 2023; 60:5482-5492. [PMID: 37316759 DOI: 10.1007/s12035-023-03429-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 06/05/2023] [Indexed: 06/16/2023]
Abstract
Mitochondria are the structures in cells that are responsible for producing energy. They contain a specific translation unit for synthesizing mitochondria-encoded respiratory chain components: the mitochondrial DNA (mt DNA). Recently, a growing number of syndromes associated with the dysfunction of mt DNA translation have been reported. However, the functions of these diseases still need to be precise and thus attract much attention. Mitochondrial tRNAs (mt tRNAs) are encoded by mt DNA; they are the primary cause of mitochondrial dysfunction and are associated with a wide range of pathologies. Previous research has shown the role of mt tRNAs in the epileptic mechanism. This review will focus on the function of mt tRNA and the role of mitochondrial aminoacyl-tRNA synthetase (mt aaRS) in order to summarize some common relevant mutant genes of mt aaRS that cause epilepsy and the specific symptoms of the disease they cause.
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Affiliation(s)
- Ling-Yue Kong
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Yi-Ze Wu
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Run-Qi Cheng
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Pei-Han Wang
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Bi-Wen Peng
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China.
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, School of Basic Medical Sciences, Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China.
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Fu Y, Jing P, Yao L, Wang H, Zhou C. Novel mitochondrial tRNALeu(UUR) 3261A > g mutation in two pedigrees with essential hypertension. Ir J Med Sci 2022. [PMID: 35657541 DOI: 10.1007/s11845-022-03039-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 05/24/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Essential hypertension (EH) was associated with mitochondrial tRNA mutations. AIMS This study was designed to assess the association between EH and mitochondrial dysfunction. METHODS A total of 30 individuals from two different Chinese families exhibit maternally inherited EH were assessed for genetic, clinical, and biochemical phenotypes pertaining to EH and mitochondrial functionality. These analyses included assessments of tRNALeu(UUR) 3261A > G mutation status, mitochondrial membrane permeability, mitochondria-associated ATP and reactive oxygen species (ROS) generation, and electron transport chain functionality. RESULTS EH was detected in 6 total analyzed members of the two families assessed in the present study, with its initial age of onset and presentation varying among patients. These patients with EH exhibited the tRNALeu(UUR) 3261A > G mutation and were of the B5 and D4 Eastern Asian mitochondrial haplogroups. This 3261A > G mutation was predicted to result in disruption of normal tRNALeu(UUR) activity owing to the destabilization of conserved base pairing (30A-40U). Consistent with this prediction, we found that cybrid cell lines exhibiting this 3261A > G mutation exhibited a ~49.05% decrease in baseline tRNALeu(UUR) levels. These cells additionally exhibited ~44.81% reductions in rates of mitochondrial translation. CONCLUSIONS To facilitate future molecular diagnosis, the 3261A > G mutation should be included in the list of hereditary risk factors. Our findings will aid in the counseling of EH families.
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Zhao LJ, Zhang ZL, Fu Y. Novel m.4268T>C mutation in the mitochondrial tRNAIle gene is associated with hearing loss in two Chinese families. World J Clin Cases 2022; 10:205-216. [PMID: 35071519 PMCID: PMC8727281 DOI: 10.12998/wjcc.v10.i1.205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/23/2021] [Accepted: 11/29/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Herein, we report the genetic, clinical, molecular and biochemical features of two Han Chinese pedigrees with suggested maternally transmitted non-syndromic hearing loss.
AIM To investigate the pathophysiology of hearing loss associated with mitochondrial tRNA mutations.
METHODS Sixteen subjects from two Chinese families with hearing loss underwent clinical, genetic, molecular, and biochemical evaluations. Biochemical characterizations included the measurements of tRNA levels using lymphoblastoid cell lines derived from five affected matrilineal relatives of these families and three control subjects.
RESULTS Three of the 16 matrilineal relatives in these families exhibited a variable seriousness and age-at-onset (8 years) of deafness. Analysis of mtDNA mutation identified the novel homoplasmic tRNAIle 4268T>C mutation in two families both belonging to haplogroup D4j. The 4268T>C mutation is located in a highly conserved base pairing (6U–67A) of tRNAIle. The elimination of 6U–67A base-pairing may change the tRNAIle metabolism. Functional mutation was supported by an approximately 64.6% reduction in the level of tRNAIle observed in the lymphoblastoid cell lines with the 4268T>C mutation, in contrast to the wild-type cell lines. The reduced level of tRNA was below the proposed threshold for normal respiration in lymphoblastoid cells. However, genotyping analysis did not detect any mutations in the prominent deafness-causing gene GJB2 in any members of the family.
CONCLUSION These data show that the novel tRNAIle 4268T>C mutation was involved in maternally transmitted deafness. However, epigenetic, other genetic, or environmental factors may be attributed to the phenotypic variability. These findings will be useful for understanding families with maternally inherited deafness.
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Affiliation(s)
- Li-Jing Zhao
- Department of Otorhinolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, Zhejiang Province, China
| | - Zhi-Li Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
| | - Yong Fu
- Department of Otorhinolaryngology Head and Neck Surgery, The Children’s Hospital, Zhejiang University School of Medicine, Hangzhou 310009, Zhejiang Province, China
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Imai-Okazaki A, Yagi N, Nitta KR, Murayama K, Ohtake A, Okazaki Y. Clinical heterogeneity in patients with m.4412G > A MT-TM mutation and different heteroplasmy levels. Mitochondrion 2021; 59:214-215. [PMID: 34089906 DOI: 10.1016/j.mito.2021.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/10/2021] [Accepted: 06/01/2021] [Indexed: 11/30/2022]
Abstract
The identification of the m.4412G > A MT-TM (mt-tRNAMet) mutation was first reported in 2019. The affected individual presented with childhood-onset seizures and myopathy and bilateral basal ganglia changes, with heteroplasmy levels in muscle as high as 90%. Here, we describe another adult-onset patient with the same mutation and additional phenotypes, including hearing impairment, cerebellar ataxia, progressive dementia, and myopathy. The 10% heteroplasmy level observed in skin fibroblasts from this patient are lower than those in the previously reported patient. Our report suggests possible clinical heterogeneity in patients with mitochondrial tRNA mutations based on heteroplasmy levels.
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Affiliation(s)
- Atsuko Imai-Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Nobuyasu Yagi
- Department of Neurology, Japanese Red Cross Shizuoka-Hospital, Shizuoka, Japan
| | - Kazuhiro R Nitta
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Kei Murayama
- Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Akira Ohtake
- Department of Pediatrics & Clinical Genomics, Saitama Medical University, Saitama, Japan; Center for Intractable Diseases, Saitama Medical University Hospital, Saitama, Japan
| | - Yasushi Okazaki
- Diagnostics and Therapeutics of Intractable Diseases, Intractable Disease Research Center, Graduate School of Medicine, Juntendo University, Tokyo, Japan; Laboratory for Comprehensive Genomic Analysis, RIKEN Center for Integrative Medical Sciences, Kanagawa, Japan.
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6
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Miwa T, Wei FY, Tomizawa K. Cdk5 regulatory subunit-associated protein 1 knockout mice show hearing loss phenotypically similar to age-related hearing loss. Mol Brain 2021; 14:82. [PMID: 34001214 PMCID: PMC8130336 DOI: 10.1186/s13041-021-00791-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 05/12/2021] [Indexed: 11/10/2022] Open
Abstract
Mitochondrial dysfunction is associated with aging and age-related hearing loss (AHL). However, the precise mechanisms underlying the pathophysiology of hearing loss remain unclear. Cdk5 regulatory subunit-associated protein 1 (CDK5RAP1) enables efficient intramitochondrial translation by catalyzing the deposition of 2-methylthio modifications on mitochondrial tRNAs. Here we investigated the effect of defective mitochondrial protein translation on hearing and AHL in a Cdk5rap1 deficiency C57BL/6 mouse model. Compared to control C57BL/6 mice, Cdk5rap1-knockout female mice displayed hearing loss phenotypically similar to AHL from an early age. The premature hearing loss in Cdk5rap1-knockout mice was associated with the degeneration of the spiral ligament and reduction of endocochlear potentials following the loss of auditory sensory cells. Furthermore, cultured primary mouse embryonic fibroblasts displayed early onset of cellular senescence associated with high oxidative stress and cell death. These results indicate that the CDK5RAP1 deficiency-induced defective mitochondrial translation might cause early hearing loss through the induction of cellular senescence and cochlear dysfunction in the inner ear. Our results suggest that the accumulation of dysfunctional mitochondria might promote AHL progression. Furthermore, our findings suggest that mitochondrial dysfunction and dysregulated mitochondrial tRNA modifications mechanistically cause AHL. Understanding the mechanisms underlying AHL will guide future clinical investigations and interventions in the attempt to mitigate the consequences of AHL.
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Affiliation(s)
- Toru Miwa
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 6068507, Japan.
- Department of Otolaryngology-Head and Neck Surgery, Kitano Hospital, Tazuke Kofukai Medical Research Institute, 2-4-20 Ougimaci, Kita-ku, Osaka, 5308480, Japan.
| | - Fan-Yan Wei
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, 1-1-1- Honjo, Chuo-ku, Kumamoto, 8608556, Japan
- Department of Modomics Biology and Medicine, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo, Aoba-ku, Sendai, Miyagi, 9808575, Japan
| | - Kazuhito Tomizawa
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, 1-1-1- Honjo, Chuo-ku, Kumamoto, 8608556, Japan
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7
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Hoser SM, Hoffmann A, Meindl A, Gamper M, Fallmann J, Bernhart SH, Müller L, Ploner M, Misslinger M, Kremser L, Lindner H, Geley S, Schaal H, Stadler PF, Huettenhofer A. Intronic tRNAs of mitochondrial origin regulate constitutive and alternative splicing. Genome Biol 2020; 21:299. [PMID: 33292386 PMCID: PMC7722341 DOI: 10.1186/s13059-020-02199-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 11/09/2020] [Indexed: 02/19/2023] Open
Abstract
BACKGROUND The presence of nuclear mitochondrial DNA (numtDNA) has been reported within several nuclear genomes. Next to mitochondrial protein-coding genes, numtDNA sequences also encode for mitochondrial tRNA genes. However, the biological roles of numtDNA remain elusive. RESULTS Employing in silico analysis, we identify 281 mitochondrial tRNA homologs in the human genome, which we term nimtRNAs (nuclear intronic mitochondrial-derived tRNAs), being contained within introns of 76 nuclear host genes. Despite base changes in nimtRNAs when compared to their mtRNA homologs, a canonical tRNA cloverleaf structure is maintained. To address potential functions of intronic nimtRNAs, we insert them into introns of constitutive and alternative splicing reporters and demonstrate that nimtRNAs promote pre-mRNA splicing, dependent on the number and positioning of nimtRNA genes and splice site recognition efficiency. A mutational analysis reveals that the nimtRNA cloverleaf structure is required for the observed splicing increase. Utilizing a CRISPR/Cas9 approach, we show that a partial deletion of a single endogenous nimtRNALys within intron 28 of the PPFIBP1 gene decreases inclusion of the downstream-located exon 29 of the PPFIBP1 mRNA. By employing a pull-down approach followed by mass spectrometry, a 3'-splice site-associated protein network is identified, including KHDRBS1, which we show directly interacts with nimtRNATyr by an electrophoretic mobility shift assay. CONCLUSIONS We propose that nimtRNAs, along with associated protein factors, can act as a novel class of intronic splicing regulatory elements in the human genome by participating in the regulation of splicing.
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Affiliation(s)
- Simon M Hoser
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020, Innsbruck, Austria.
| | - Anne Hoffmann
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Philipp-Rosenthal-Str. 27, 04103, Leipzig, Germany
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, 04107, Leipzig, Germany
| | - Andreas Meindl
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020, Innsbruck, Austria
| | - Maximilian Gamper
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020, Innsbruck, Austria
| | - Jörg Fallmann
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, 04107, Leipzig, Germany
| | - Stephan H Bernhart
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, 04107, Leipzig, Germany
| | - Lisa Müller
- Institute for Virology, Medical Faculty Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Melanie Ploner
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020, Innsbruck, Austria
| | - Matthias Misslinger
- Division of Molecular Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Leopold Kremser
- Division of Clinical Biochemistry, Protein Micro-Analysis Facility, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Herbert Lindner
- Division of Clinical Biochemistry, Protein Micro-Analysis Facility, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Stephan Geley
- Institute of Pathophysiology, Biocenter, Medical University of Innsbruck, 6020, Innsbruck, Austria
| | - Heiner Schaal
- Institute for Virology, Medical Faculty Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
| | - Peter F Stadler
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, 04107, Leipzig, Germany
- Max Planck Institute for Mathematics in the Sciences, Inselstraße 22, 04103, Leipzig, Germany
| | - Alexander Huettenhofer
- Division of Genomics and RNomics, Biocenter, Medical University of Innsbruck, 6020, Innsbruck, Austria.
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Kripps KA, Friederich MW, Chen T, Larson AA, Mirsky DM, Wang Y, Tanji K, Knight KM, Wong LJ, Van Hove JLK. A novel acceptor stem variant in mitochondrial tRNATyr impairs mitochondrial translation and is associated with a severe phenotype. Mol Genet Metab 2020; 131:398-404. [PMID: 33279411 PMCID: PMC7749820 DOI: 10.1016/j.ymgme.2020.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 11/13/2020] [Accepted: 11/13/2020] [Indexed: 11/25/2022]
Abstract
Genetic defects in mitochondrial DNA encoded tRNA genes impair mitochondrial translation with resultant defects in the mitochondrial respiratory chain and oxidative phosphorylation system. The phenotypic spectrum of disease seen in mitochondrial tRNA defects is variable and proving pathogenicity of new variants is challenging. Only three pathogenic variants have been described previously in the mitochondrial tRNATyr gene MT-TY, with the reported phenotypes consisting largely of adult onset myopathy and ptosis. We report a patient with a novel MT-TY acceptor stem variant m.5889A>G at high heteroplasmy in muscle, low in blood, and absent in the mother's blood. The phenotype consisted of a childhood-onset severe multi-system disorder characterized by a neurodegenerative course including ataxia and seizures, failure-to-thrive, combined myopathy and neuropathy, and hearing and vision loss. Brain imaging showed progressive atrophy and basal ganglia calcifications. Mitochondrial biomarkers lactate and GDF15 were increased. Functional studies showed a deficient activity of the respiratory chain enzyme complexes containing mtDNA-encoded subunits I, III and IV. There were decreased steady state levels of these mitochondrial complex proteins, and presence of incompletely assembled complex V forms in muscle. These changes are typical of a mitochondrial translational defect. These data support the pathogenicity of this novel variant. Careful review of variants in MT-TY additionally identified two other pathogenic variants, one likely pathogenic variant, nine variants of unknown significance, five likely benign and four benign variants.
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Affiliation(s)
- Kimberly A Kripps
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, CO, USA
| | - Marisa W Friederich
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, CO, USA; Department of Pathology and Laboratory Medicine, Children's Hospital Colorado, 13121 East 16th Avenue, Aurora, CO, USA
| | - Ting Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Endocrinology, Genetics and Metabolism, Children's Hospital of Soochow University, Suzhou, China
| | - Austin A Larson
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, CO, USA
| | - David M Mirsky
- Department of Radiology, University of Colorado, and Children's Hospital Colorado, Aurora, CO, USA
| | - Yue Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Kurenai Tanji
- Division of Neuropathology, Columbia University Medical Center, New York, NY, USA
| | - Kaz M Knight
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, CO, USA
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Johan L K Van Hove
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, CO, USA; Department of Pathology and Laboratory Medicine, Children's Hospital Colorado, 13121 East 16th Avenue, Aurora, CO, USA.
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9
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Zhang Z, Liu M, He J, Zhang X, Chen Y, Li H. Maternally inherited coronary heart disease is associated with a novel mitochondrial tRNA mutation. BMC Cardiovasc Disord 2019; 19:293. [PMID: 31842766 PMCID: PMC6912950 DOI: 10.1186/s12872-019-01284-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 11/27/2019] [Indexed: 01/26/2023] Open
Abstract
Background Coronary heart disease (CHD) is the most common cause of mortality globally, yet mitochondrial genetic mutations associated with CHD development remain incompletely understood. Methods The subjects from three Chinese families with LHON underwent clinical, genetic, molecular, and biochemical evaluations. Biochemical characterizations included measuring the effects of the15910C > T mutation on tRNAThr levels, enzymatic activity of electron transport chain complexes, membrane permeability, and the mitochondria-mediated generation of both reactive oxygen species (ROS) and adenosine triphosphate (ATP). Results We characterize mitochondrial genetic mutations in a three-generation Chinese family exhibiting signs of maternally inherited CHD. Of the 24 different family members in this pedigree we assessed, CHD was detected in 6, with variable severity and age of first appearance. When we sequenced the mitochondrial genomes of these individuals, we found a tRNAThr 15910C > T mutation of the Eastern Asian haplogroup M7b’c. This mutation is predicted to destabilize the strongly conserved (24C-10G) base-pairing, thereby disrupting tRNAThr functionality. When we performed Northern blotting, we detected we observed a 37.5% reduction in tRNAThr levels at baseline in cybrid cell lines bearing the 15910C > T mutation. When we conducted western blot analysis, we detected a ~ 24.96% decrease in mitochondrial translation rates in these same cells. Conclusions In the present report, Together these findings suggest a possible link between this 15910C > T tRNAThr mutation and CHD, potentially offering new avenues for future disease intervention.
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Affiliation(s)
- Zhenxiao Zhang
- Department of Emergency, Affiliated hospital of Qingdao university, Jiangsu Road No. 16, Qingdao, 266000, Shandong, China
| | - Mingyang Liu
- Department of Emergency, Affiliated hospital of Qingdao university, Jiangsu Road No. 16, Qingdao, 266000, Shandong, China
| | - Jianshuai He
- Department of Anesthesiology, Affiliated hospital of Qingdao university, Qingdao, 266000, Shandong, China
| | - Xiaotian Zhang
- Department of Anesthesiology, Affiliated hospital of Qingdao university, Qingdao, 266000, Shandong, China
| | - Yuehua Chen
- Department of ICU, Affiliated hospital of Qingdao university, Qingdao, 266000, Shandong, China
| | - Hui Li
- Department of Emergency, Affiliated hospital of Qingdao university, Jiangsu Road No. 16, Qingdao, 266000, Shandong, China.
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10
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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11
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Li H, Geng J, Yu H, Tang X, Yang X, Xue L. Mitochondrial tRNAThr 15909A>G mutation associated with hypertension in a Chinese Han pedigree. Biochem Biophys Res Commun 2017; 495:574-581. [PMID: 29129694 DOI: 10.1016/j.bbrc.2017.11.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 11/08/2017] [Indexed: 01/06/2023]
Abstract
Mitochondrial DNA mutations are one of the molecular genetic bases of hypertension. Here, we performed clinical, genetic and mutational evaluation, molecular characterization as well as biochemical analysis of a Chinese Han family with maternally inherited hypertension. The m.15909A > G variant in tRNAThr was identified. This mutation abolished a highly conserved base pairing (11U-24A) in the D-stem of tRNAThr and affected the structure and function of mitochondrial tRNAThr. As a result, the overall levels of mitochondrial translation products was decreased. The reduced mitochondrial protein synthesis resulted in the decrease in the activity of complex, and in turn, the production of ATP decreased and the generation of ROS increased. The m.15909A > G mutation maybe an inherited factor leading to the development of hypertension in this Chinese Han pedigree.
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Affiliation(s)
- Haiying Li
- Department of Cardiology, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, China; Department of Cardiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, China
| | - Junwei Geng
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Han Yu
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Xiaowen Tang
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Xiangjun Yang
- Department of Cardiology, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, China.
| | - Ling Xue
- Attardi Institute of Mitochondrial Biomedicine, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
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12
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HEIDARI MM, DERAKHSHANI M, SEDIGHI F, FORUZAN-NIA SK. Mutation Analysis of the Mitochondrial tRNA Genes in Iranian Coronary Atherosclerosis Patients. Iran J Public Health 2017; 46:1379-1385. [PMID: 29308382 PMCID: PMC5750350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Atherosclerosis is a disease that affects large and medium size arteries in the body that underlies coronary heart disease. Several nucleotide changes in mitochondrial tRNA genes have been reported in various diseases. The purpose of the study was to identify hotspot mitochondrial tRNA mutations in atherosclerotic patients. METHODS In this case-control study, the variations of ten mitochondrial tRNA genes (about 50%) were investigated in 70 patients from October 2013 and June 2015 suffered from atherosclerosis. The related mitochondrial area was amplified using PCR methid. The mutation analysis was performed by Single Strand Conformational Polymorphism (SSCP) and Restriction Fragment Length Polymorphism (RFLP). All the positive samples were sequenced. RESULTS We found one novel heteroplasmic mutation (m.5725T>G) and three reported single nucleotide polymorphisms (SNPs) previously in other diseases including m.5568A>G, m.5711A>G and m.12308A>G. CONCLUSION These tRNA mutations can alter their steady state level and affect the structure of tRNA. The role of mitochondrial tRNA mutations in the pathogenesis of atherosclerosis could potentially be important for the understanding of mitochondrial dysfunction in coronary atherosclerotic plaque formation.
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Affiliation(s)
- Mohammad Mehdi HEIDARI
- Dept. of Biology, Faculty of Science, Yazd University, Yazd, Iran,Corresponding Author:
| | | | - Fatemeh SEDIGHI
- Dept. of Biology, Faculty of Science, Yazd University, Yazd, Iran
| | - Seyed Khalil FORUZAN-NIA
- Dept. of Cardiac Surgery, Afshar Hospital, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
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13
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Oerum S, Roovers M, Leichsenring M, Acquaviva-Bourdain C, Beermann F, Gemperle-Britschgi C, Fouilhoux A, Korwitz-Reichelt A, Bailey HJ, Droogmans L, Oppermann U, Sass JO, Yue WW. Novel patient missense mutations in the HSD17B10 gene affect dehydrogenase and mitochondrial tRNA modification functions of the encoded protein. Biochim Biophys Acta Mol Basis Dis 2017; 1863:3294-3302. [PMID: 28888424 DOI: 10.1016/j.bbadis.2017.09.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 08/16/2017] [Accepted: 09/05/2017] [Indexed: 10/18/2022]
Abstract
MRPP2 (also known as HSD10/SDR5C1) is a multifunctional protein that harbours both catalytic and non-catalytic functions. The protein belongs to the short-chain dehydrogenase/reductases (SDR) family and is involved in the catabolism of isoleucine in vivo and steroid metabolism in vitro. MRPP2 also moonlights in a complex with the MRPP1 (also known as TRMT10C) protein for N1-methylation of purines at position 9 of mitochondrial tRNA, and in a complex with MRPP1 and MRPP3 (also known as PRORP) proteins for 5'-end processing of mitochondrial precursor tRNA. Inherited mutations in the HSD17B10 gene encoding MRPP2 protein lead to a childhood disorder characterised by progressive neurodegeneration, cardiomyopathy or both. Here we report two patients with novel missense mutations in the HSD17B10 gene (c.34G>C and c.526G>A), resulting in the p.V12L and p.V176M substitutions. Val12 and Val176 are highly conserved residues located at different regions of the MRPP2 structure. Recombinant mutant proteins were expressed and characterised biochemically to investigate their effects towards the functions of MRPP2 and associated complexes in vitro. Both mutant proteins showed significant reduction in the dehydrogenase, methyltransferase and tRNA processing activities compared to wildtype, associated with reduced stability for protein with p.V12L, whereas the protein carrying p.V176M showed impaired kinetics and complex formation. This study therefore identified two distinctive molecular mechanisms to explain the biochemical defects for the novel missense patient mutations.
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Affiliation(s)
- Stephanie Oerum
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Old Road Campus, Roosevelt Drive, OX3 7DQ Oxford, UK
| | - Martine Roovers
- Institut de Recherches Microbiologiques Jean-Marie Wiame, Bruxelles, Belgium
| | - Michael Leichsenring
- Department for Children and Adolescent Medicine, Ulm University Medical School, Ulm, Germany
| | - Cécile Acquaviva-Bourdain
- Groupement Hospitalier Est, Centre de Biologie Est, Service Maladies Héréditaires du Métabolisme, Bron, France
| | - Frauke Beermann
- University of Freiburg Children's Hospital, Laboratory of Clinical Biochemistry and Metabolism, Freiburg, Germany
| | - Corinne Gemperle-Britschgi
- University Children's Hospital and Children's Research Center, Clinical Chemistry & Biochemistry, Zürich, Switzerland
| | - Alain Fouilhoux
- Centre de Référence des Maladies Héréditaires du Métabolisme, HCL, Bron, France
| | - Anne Korwitz-Reichelt
- Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences, von-Liebig-Str. 20, 53359 Rheinbach, Germany
| | - Henry J Bailey
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Old Road Campus, Roosevelt Drive, OX3 7DQ Oxford, UK
| | - Louis Droogmans
- Laboratoire de Microbiologie, Universite libre de Bruxelles, Belgium
| | - Udo Oppermann
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Old Road Campus, Roosevelt Drive, OX3 7DQ Oxford, UK; Botnar Research Centre, NIHR Oxford Biomedical Research Unit, Oxford, UK
| | - Jörn Oliver Sass
- University of Freiburg Children's Hospital, Laboratory of Clinical Biochemistry and Metabolism, Freiburg, Germany; University Children's Hospital and Children's Research Center, Clinical Chemistry & Biochemistry, Zürich, Switzerland; Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences, von-Liebig-Str. 20, 53359 Rheinbach, Germany.
| | - Wyatt W Yue
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Old Road Campus, Roosevelt Drive, OX3 7DQ Oxford, UK.
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14
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Ding Y, Xia BH, Zhang CJ, Zhuo GC. Mutations in mitochondrial tRNA genes may be related to insulin resistance in women with polycystic ovary syndrome. Am J Transl Res 2017; 9:2984-2996. [PMID: 28670386 PMCID: PMC5489898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/26/2017] [Indexed: 06/07/2023]
Abstract
Polycystic ovary syndrome (PCOS) is a very common endocrine disorder affecting women of reproductive age. Insulin resistance (IR), a central component of this disease, occurs in 30%-40% of women with PCOS. To date, the molecular mechanism underlying PCOS-IR remains largely unknown. Most recently, increasing evidence has shown that mitochondrial dysfunction caused by mitochondrial DNA (mtDNA) mutations plays important roles in the pathogenesis of PCOS-IR. To identify the contribution of mitochondrial tRNA (mt-tRNA) mutations in this disease, we screened 80 women with PCOS-IR and 50 healthy control participants for mt-tRNA mutations. After genetic amplification and direct sequencing, we identified nine mt-tRNA mutations that were potentially associated with PCOS-IR: mt-tRNALeu(UUR) A3302G and C3275A mutations, mt-tRNAGln T4363C and T4395C mutations, mt-tRNASer(UCN) C7492T mutation, mt-tRNAAsp A7543G mutation, mt-tRNALys A8343G mutation, mt-tRNAArg T10454C mutation and mt-tRNAGlu A14693G mutation. These mutations were localized at evolutionarily conserved nucleotides and altered the secondary structure of mt-tRNAs, thus resulting in failure of mt-tRNA metabolism. Moreover, molecular and biochemical analysis revealed that levels of 8-OHdG, malondialdehyde and reactive oxygen species were increased in patients with PCOS-IR carrying these mt-tRNA mutations compared with in healthy control participants, whereas superoxide dismutase levels, mitochondrial copy number, membrane potential and ATP levels were significantly reduced. Taken together, our data indicate that mt-tRNAs are key locations for pathogenic mutations associated with PCOS-IR. Mitochondrial dysfunction caused by mt-tRNA mutations may be involved in the pathogenesis of PCOS-IR. Thus, our findings provide novel insight into the pathophysiology of this disorder.
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Affiliation(s)
- Yu Ding
- Department of Central Laboratory, Hangzhou First People’s Hospital, Nanjing Medical UniversityHangzhou, China
| | - Bo-Hou Xia
- Department of Pharmacy, Hunan University of Chinese MedicineChangsha, China
| | - Cai-Juan Zhang
- Department of Gynecology and Obstetrics, Hangzhou First People’s Hospital, Nanjing Medical UniversityHangzhou, China
| | - Guang-Chao Zhuo
- Department of Central Laboratory, Hangzhou First People’s Hospital, Nanjing Medical UniversityHangzhou, China
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15
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WANG CM, ZHANG XJ, MA YJ, LI X. Mutational Analysis of Mitochondrial tRNA Genes in Patients with Asthma. Iran J Public Health 2017; 46:620-625. [PMID: 28560192 PMCID: PMC5442274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Mitochondria are autonomous cellular organelles that oversee a variety of functions such as metabolism, energy production, calcium buffering, and cell fate determination. Most recently, mitochondrial dysfunction caused by mitochondrial mutations played important roles in the pathogenesis of asthma. However, the frequency of mitochondrial tRNA mutations in asthma is largely unknown. METHODS Overall, 200 patients with asthma and 100 healthy control subjects were recruited between Jan 2015 and Dec 2015 at the Guangming New District People's Hospital, Shenzhen, Guangdong Province, China. We first performed PCR amplification of the mitochondrial tRNA genes and subsequently sequenced the PCR products, and we used the pathogenicity scoring system to evaluate the potential role of these mutations. RESULTS Two patients carrying the tRNAThr G15927A mutation, three patients carrying the tRNAAla T5655C mutation and one patient carrying the tRNAGlu A14693G mutation, these mutations were absent in healthy controls. Moreover, these mutations located at positions highly conserved between different species, and may cause a failure in mitochondrial tRNA metabolism, consequently result in mitochondrial dysfunction that responsible for asthma. In addition, the pathogenicity scoring system showed that these mutations should be regarded as "pathogenic". CONCLUSION Mitochondrial tRNA mutations caused the mitochondrial dysfunction may be involved in the pathogenesis of asthma. Thus, this study provided novel insight into the molecular mechanism underlying mitochondrial tRNA mutations in asthma. Moreover, screening for the mitochondrial tRNA mutations was advised for the diagnosis of patients with asthma.
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Affiliation(s)
- Chun Mei WANG
- Bright New District Shenzhen City, Guangdong Province People’s Hospital, Shenzhen, Guangdong, China
| | - Xiao Jing ZHANG
- Dept. of Pathology, Medical College, Shenzhen University, Shenzhen, Guangdong, China,Corresponding Author:
| | - Ying Jun MA
- Bright New District Shenzhen City, Guangdong Province People’s Hospital, Shenzhen, Guangdong, China
| | - Xia LI
- Bright New District Shenzhen City, Guangdong Province People’s Hospital, Shenzhen, Guangdong, China
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16
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Abstract
BACKGROUND The mitochondrial genome is transcribed as continuous polycistrons of RNA containing multiple genes. As a consequence, post-transcriptional events are critical for the regulation of gene expression and therefore all aspects of mitochondrial function. One particularly important process is the m1A/m1G RNA methylation of the ninth position of different mitochondrial tRNAs, which allows efficient processing of mitochondrial mRNAs and protein translation, and de-regulation of genes involved in these processes has been associated with altered mitochondrial function. Although mitochondria play a key role in cancer, the status of mitochondrial RNA processing in tumorigenesis is unknown. METHODS We measure and assess mitochondrial RNA processing using integrated genomic analysis of RNA sequencing and genotyping data from 1226 samples across 12 different cancer types. We focus on the levels of m1A and m1G RNA methylation in mitochondrial tRNAs in normal and tumor samples and use supervised and unsupervised statistical analysis to compare the levels of these modifications to patient whole genome genotypes, nuclear gene expression, and survival outcomes. RESULTS We find significant changes to m1A and m1G RNA methylation levels in mitochondrial tRNAs in tumor tissues across all cancers. Pathways of RNA processing are strongly associated with methylation levels in normal tissues (P = 3.27 × 10-31), yet these associations are lost in tumors. Furthermore, we report 18 gene-by-disease-state interactions where altered RNA methylation levels occur under cancer status conditional on genotype, implicating genes associated with mitochondrial function or cancer (e.g., CACNA2D2, LMO2, and FLT3) and suggesting that nuclear genetic variation can potentially modulate an individual's ability to maintain unaltered rates of mitochondrial RNA processing under cancer status. Finally, we report a significant association between the magnitude of methylation level changes in tumors and patient survival outcomes. CONCLUSIONS We report widespread variation of mitochondrial RNA processing between normal and tumor tissues across all cancer types investigated and show that these alterations are likely modulated by patient genotype and may impact patient survival outcomes. These results highlight the potential clinical relevance of altered mitochondrial RNA processing and provide broad new insights into the importance and complexity of these events in cancer.
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Affiliation(s)
- Youssef Idaghdour
- Biology Program, Division of Science and Mathematics, New York University Abu Dhabi, PO Box 129188, Abu Dhabi, United Arab Emirates.
| | - Alan Hodgkinson
- Department of Medical and Molecular Genetics, Guy's Hospital, King's College London, London, SE1 9RT, UK.
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17
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Long Y, Jackman JE. In vitro substrate specificities of 3'-5' polymerases correlate with biological outcomes of tRNA 5'-editing reactions. FEBS Lett 2015; 589:2124-30. [PMID: 26143376 DOI: 10.1016/j.febslet.2015.06.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 06/17/2015] [Indexed: 10/23/2022]
Abstract
Protozoan mitochondrial tRNAs (mt-tRNAs) are repaired by a process known as 5'-editing. Mt-tRNA sequencing revealed organism-specific patterns of editing G-U base pairs, wherein some species remove G-U base pairs during 5'-editing, while others retain G-U pairs in the edited tRNA. We tested whether 3'-5' polymerases that catalyze the repair step of 5'-editing exhibit organism-specific preferences that explain the treatment of G-U base pairs. Biochemical and kinetic approaches revealed that a 3'-5' polymerase from Acanthamoeba castellanii tolerates G-U wobble pairs in editing substrates much more readily than several other enzymes, consistent with its biological pattern of editing.
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Affiliation(s)
- Yicheng Long
- Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, United States
| | - Jane E Jackman
- Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, United States.
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18
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McCann BJ, Tuppen HAL, Küsters B, Lammens M, Smeitink JAM, Taylor RW, Rodenburg RJ, Wortmann SB. A novel mitochondrial DNA m.7507A>G mutation is only pathogenic at high levels of heteroplasmy. Neuromuscul Disord 2014; 25:262-7. [PMID: 25497401 DOI: 10.1016/j.nmd.2014.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 10/15/2014] [Accepted: 11/06/2014] [Indexed: 11/25/2022]
Abstract
We present a Dutch family with a novel disease-causing mutation in the mitochondrial tRNA(Ser(UCN)) gene, m.7507A>G. The index patient died during the neonatal period due to cardio-respiratory failure and fatal lactic acidosis. A second patient, his cousin, has severe hearing loss necessitating cochlear implants and progressive exercise intolerance. Laboratory investigations of both patients revealed combined deficiencies of the enzyme complexes of the mitochondrial respiratory chain in several tissues. Reduced levels of fully assembled complexes I and IV in fibroblasts by BN-PAGE associated with (near) homoplasmic levels of the m.7507A>G mutation in several tissues and a severe reduction in the steady-state level of mt-tRNA(Ser(UCN)) in fibroblasts were observed. The novel mitochondrial DNA mutation was shown to segregate with disease; several healthy maternal family members showed high heteroplasmy levels (up to 76 ± 4% in blood and 68 ± 4% in fibroblasts) which did not lead to any alterations in the activities of the enzyme complexes of the respiratory chain in fibroblasts or clinical signs and symptoms. We hereby conclude that the m.7507A>G mutation causes a heterogeneous clinical phenotype and is only pathogenic at very high levels of mtDNA heteroplasmy.
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Affiliation(s)
- Beverly Jo McCann
- Nijmegen Centre for Mitochondrial Disorders (NCMD), Amalia Children's Hospital, Nijmegen, The Netherlands; Department of Biology, Darmstadt University of Technology, Darmstadt, Germany
| | - Helen A L Tuppen
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Benno Küsters
- Department of Pathology, Radboudumc, Nijmegen, The Netherlands; Department of Pathology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Martin Lammens
- Department of Pathology, Antwerp University Hospital, Antwerp, Belgium; University of Antwerp, Antwerp, Belgium
| | - Jan A M Smeitink
- Nijmegen Centre for Mitochondrial Disorders (NCMD), Amalia Children's Hospital, Nijmegen, The Netherlands
| | - Robert W Taylor
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Richard J Rodenburg
- Nijmegen Centre for Mitochondrial Disorders (NCMD), Amalia Children's Hospital, Nijmegen, The Netherlands
| | - Saskia B Wortmann
- Nijmegen Centre for Mitochondrial Disorders (NCMD), Amalia Children's Hospital, Nijmegen, The Netherlands.
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19
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Ogawa T, Shimizu A, Takahashi K, Hidaka M, Masaki H. Mitochondrial tRNA cleavage by tRNA-targeting ribonuclease causes mitochondrial dysfunction observed in mitochondrial disease. Biochem Biophys Res Commun 2014; 451:131-6. [PMID: 25065742 DOI: 10.1016/j.bbrc.2014.07.084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 07/17/2014] [Indexed: 11/21/2022]
Abstract
Mitochondrial DNA (mtDNA) is a genome possessed by mitochondria. Since reactive oxygen species (ROS) are generated during aerobic respiration in mitochondria, mtDNA is commonly exposed to the risk of DNA damage. Mitochondrial disease is caused by mitochondrial dysfunction, and mutations or deletions on mitochondrial tRNA (mt tRNA) genes are often observed in mtDNA of patients with the disease. Hence, the correlation between mt tRNA activity and mitochondrial dysfunction has been assessed. Then, cybrid cells, which are constructed by the fusion of an enucleated cell harboring altered mtDNA with a ρ(0) cell, have long been used for the analysis due to difficulty in mtDNA manipulation. Here, we propose a new method that involves mt tRNA cleavage by a bacterial tRNA-specific ribonuclease. The ribonuclease tagged with a mitochondrial-targeting sequence (MTS) was successfully translocated to the mitochondrial matrix. Additionally, mt tRNA cleavage, which resulted in the decrease of cytochrome c oxidase (COX) activity, was observed.
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20
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González-Vioque E, Bornstein B, Gallardo ME, Fernández-Moreno MÁ, Garesse R. The pathogenicity scoring system for mitochondrial tRNA mutations revisited. Mol Genet Genomic Med 2013; 2:107-14. [PMID: 24689073 PMCID: PMC3960052 DOI: 10.1002/mgg3.47] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 09/27/2013] [Accepted: 10/09/2013] [Indexed: 11/14/2022] Open
Abstract
Confirming the pathogenicity of mitochondrial tRNA point mutations is one of the classical challenges in the field of mitochondrial medicine. In addition to genetic and functional studies, the evaluation of a genetic change using a pathogenicity scoring system is extremely useful to discriminate between disease-causing mutations from neutral polymorphisms. The pathogenicity scoring system is very robust for confirming pathogenicity, especially of mutations that show impaired activity in functional studies. However, mutations giving normal results using the same functional approaches are disregarded, and this compromises the power of the system to rule out pathogenicity. We propose to include a new criterion in the pathogenicity scoring systems regarding mutations which fail to show any mitochondrial defect in functional studies. To evaluate this proposal we characterized two mutations, m.8296A>G and m.8347A>G, in the mitochondrial tRNALys gene (MT-TK) using trans-mitochondrial cybrid analysis. m.8347A>G mutation severely impairs oxidative phosphorylation, suggesting that it is highly pathogenic. By contrast, the behavior of cybrids homoplasmic for the m.8296A>G mutation is similar to cybrids containing wild-type mitochondrial DNA (mtDNA). The results indicate that including not only positive but also negative outcomes of functional studies in the scoring system is critical for facilitating the diagnosis of this complex group of diseases.
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Affiliation(s)
- Emiliano González-Vioque
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid 28029, Madrid, Spain ; Laboratorio de Enfermedades Mitocondriales, Instituto de Investigación Sanitaria Hospital 12 de Octubre (i+12) Madrid, Spain
| | - Belén Bornstein
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid 28029, Madrid, Spain ; Servicio de Bioquímica, Instituto de Investigación Sanitaria Puerta de Hierro Majadahonda Madrid, Spain
| | - María Esther Gallardo
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid 28029, Madrid, Spain ; Laboratorio de Enfermedades Mitocondriales, Instituto de Investigación Sanitaria Hospital 12 de Octubre (i+12) Madrid, Spain
| | - Miguel Ángel Fernández-Moreno
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid 28029, Madrid, Spain ; Laboratorio de Enfermedades Mitocondriales, Instituto de Investigación Sanitaria Hospital 12 de Octubre (i+12) Madrid, Spain
| | - Rafael Garesse
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Universidad Autónoma de Madrid 28029, Madrid, Spain ; Laboratorio de Enfermedades Mitocondriales, Instituto de Investigación Sanitaria Hospital 12 de Octubre (i+12) Madrid, Spain
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21
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Zhou L, Wang H, Wei J, Wang Y, Wang Y. No association between mitochondrial tRNA(Val) T1658C mutation and chronic progressive external ophthalmoplegia (CPEO). ACTA ACUST UNITED AC 2013; 25:385-6. [PMID: 23815321 DOI: 10.3109/19401736.2013.803097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mutations in mitochondrial tRNA genes are one of the most important causes of mitochondrial diseases. Recently, a novel mt-tRNA(Val) T1658C mutation has been reported to be associated with chronic progressive external ophthalmoplegia (CPEO). To test this association, we performed a phylogenetic analysis of T1658C mutation, moreover, we used the bioinformatic tool to predict the thermodynamic change of tRNA(Val) with and without this mutation. Surprisingly, T1658C mutation was not evolutionary conserved and had little effect on tRNA(Val) folding. These data indicated that T1658C mutation should still be categorized as a polymorphism.
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Affiliation(s)
- Lijun Zhou
- First affiliated Hospital of Henan University of Science and Technology , Luoyang , People's Republic of China and
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