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Lin Y, Yang B, Huang Y, Zhang Y, Jiang Y, Ma L, Shen YQ. Mitochondrial DNA-targeted therapy: A novel approach to combat cancer. CELL INSIGHT 2023; 2:100113. [PMID: 37554301 PMCID: PMC10404627 DOI: 10.1016/j.cellin.2023.100113] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/14/2023] [Accepted: 07/16/2023] [Indexed: 08/10/2023]
Abstract
Mitochondrial DNA (mtDNA) encodes proteins and RNAs that are essential for mitochondrial function and cellular homeostasis, and participates in important processes of cellular bioenergetics and metabolism. Alterations in mtDNA are associated with various diseases, especially cancers, and are considered as biomarkers for some types of tumors. Moreover, mtDNA alterations have been found to affect the proliferation, progression and metastasis of cancer cells, as well as their interactions with the immune system and the tumor microenvironment (TME). The important role of mtDNA in cancer development makes it a significant target for cancer treatment. In recent years, many novel therapeutic methods targeting mtDNA have emerged. In this study, we first discussed how cancerogenesis is triggered by mtDNA mutations, including alterations in gene copy number, aberrant gene expression and epigenetic modifications. Then, we described in detail the mechanisms underlying the interactions between mtDNA and the extramitochondrial environment, which are crucial for understanding the efficacy and safety of mtDNA-targeted therapy. Next, we provided a comprehensive overview of the recent progress in cancer therapy strategies that target mtDNA. We classified them into two categories based on their mechanisms of action: indirect and direct targeting strategies. Indirect targeting strategies aimed to induce mtDNA damage and dysfunction by modulating pathways that are involved in mtDNA stability and integrity, while direct targeting strategies utilized molecules that can selectively bind to or cleave mtDNA to achieve the therapeutic efficacy. This study highlights the importance of mtDNA-targeted therapy in cancer treatment, and will provide insights for future research and development of targeted drugs and therapeutic strategies.
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Affiliation(s)
- Yumeng Lin
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Bowen Yang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Yibo Huang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - You Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Yu Jiang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Longyun Ma
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Ying-Qiang Shen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
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Hippen M, Zsurka G, Peeva V, Machts J, Schwiecker K, Debska-Vielhaber G, Wiesner RJ, Vielhaber S, Kunz WS. Novel Pathogenic Sequence Variation m.5789T>C Causes NARP Syndrome and Promotes Formation of Deletions of the Mitochondrial Genome. Neurol Genet 2022; 8:e660. [PMID: 35252560 PMCID: PMC8893589 DOI: 10.1212/nxg.0000000000000660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 01/10/2022] [Indexed: 11/15/2022]
Abstract
Background and Objectives We report the pathogenic sequence variant m.5789T>C in the anticodon stem of the mitochondrial tRNA for cysteine as a novel cause of neuropathy, ataxia, and retinitis pigmentosa (NARP), which is usually associated with pathogenic variants in the MT-ATP6 gene. Methods To address the correlation of oxidative phosphorylation deficiency with mutation loads, we performed genotyping on single laser-dissected skeletal muscle fibers. Stability of the mitochondrial tRNACys was investigated by Northern blotting. Accompanying deletions of the mitochondrial genome were detected by long-range PCR and their breakpoints were determined by sequencing of single-molecule amplicons. Results The sequence variant m.5789T>C, originating from the patient's mother, decreases the stability of the mitochondrial tRNA for cysteine by disrupting the anticodon stem, which subsequently leads to a combined oxidative phosphorylation deficiency. In parallel, we observed a prominent cluster of low-abundance somatic deletions with breakpoints in the immediate vicinity of the m.5789T>C variant. Strikingly, all deletion-carrying mitochondrial DNA (mtDNA) species, in which the corresponding nucleotide position was not removed, harbored the mutant allele, and none carried the wild-type allele. Discussion In addition to providing evidence for the novel association of a tRNA sequence alteration with NARP syndrome, our observations support the hypothesis that single nucleotide changes can lead to increased occurrence of site-specific mtDNA deletions through the formation of an imperfect repeat. This finding might be relevant for understanding mechanisms of deletion generation in the human mitochondrial genome.
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Affiliation(s)
- Marius Hippen
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Gábor Zsurka
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Viktoriya Peeva
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Judith Machts
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Kati Schwiecker
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Grazyna Debska-Vielhaber
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Rudolf J Wiesner
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Stefan Vielhaber
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
| | - Wolfram S Kunz
- Division of Neurochemistry (M.H., G.Z., V.P., W.S.K.), Institute of Experimental Epileptology and Cognition Research, University of Bonn; Department of Epileptology (G.Z., W.S.K.), University of Bonn; Center for Behavioral Brain Sciences (CBBS) (J.M.), Magdeburg; Department of Neurology (K.S., G.D.-V., S.V.), University of Magdeburg; and Institute of Vegetative Physiology (R.J.W.), University of Cologne, Germany
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Yang L, Guo Q, Leng J, Wang K, Ding Y. Late onset of type 2 diabetes is associated with mitochondrial tRNA Trp A5514G and tRNA Ser(AGY) C12237T mutations. J Clin Lab Anal 2021; 36:e24102. [PMID: 34811812 PMCID: PMC8761459 DOI: 10.1002/jcla.24102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/19/2021] [Accepted: 10/26/2021] [Indexed: 12/16/2022] Open
Abstract
Background Mitochondrial dysfunctions caused by mitochondrial DNA (mtDNA) pathogenic mutations play putative roles in type 2 diabetes mellitus (T2DM) progression. But the underlying mechanism remains poorly understood. Methods A large Chinese family with maternally inherited diabetes and deafness (MIDD) underwent clinical, genetic, and molecular assessment. PCR and sequence analysis are carried out to detect mtDNA variants in affected family members, in addition, phylogenetic conservation analysis, haplogroup classification, and pathogenicity scoring system are performed. Moreover, the GJB2, GJB3, GJB6, and TRMU genes mutations are screened by PCR‐Sanger sequencing. Results Six of 18 matrilineal subjects manifested different clinical phenotypes of diabetes. The average age at onset of diabetic patients is 52 years. Screening for the entire mitochondrial genomes suggests the co‐existence of two possibly pathogenic mutations: tRNATrp A5514G and tRNASer(AGY) C12237T, which belongs to East Asia haplogroup G2a. By molecular level, m.A5514G mutation resides at acceptor stem of tRNATrp (position 3), which is critical for steady‐state level of tRNATrp. Conversely, m.C12237T mutation occurs in the variable region of tRNASer(AGY) (position 31), which creates a novel base‐pairing (11A‐31T). Thus, the mitochondrial dysfunctions caused by tRNATrp A5514G and tRNASer(AGY) C12237T mutations, may be associated with T2DM in this pedigree. But we do not find any functional mutations in those nuclear genes. Conclusion Our findings suggest that m.A5514G and m.C12337T mutations are associated with T2DM, screening for mt‐tRNA mutations is useful for molecular diagnosis and prevention of mitochondrial diabetes.
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Affiliation(s)
- Liuchun Yang
- Central Laboratory, the Fourth School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China
| | - Qinxian Guo
- Central Laboratory, the Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhang Leng
- Central Laboratory, the Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Keyi Wang
- Central Laboratory, the Fourth School of Clinical Medicine, Zhejiang Chinese Medical University, Hangzhou, China.,Central Laboratory, the Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yu Ding
- Central Laboratory, the Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
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Helm M, Schmidt-Dengler MC, Weber M, Motorin Y. General Principles for the Detection of Modified Nucleotides in RNA by Specific Reagents. Adv Biol (Weinh) 2021; 5:e2100866. [PMID: 34535986 DOI: 10.1002/adbi.202100866] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/09/2021] [Indexed: 12/16/2022]
Abstract
Epitranscriptomics heavily rely on chemical reagents for the detection, quantification, and localization of modified nucleotides in transcriptomes. Recent years have seen a surge in mapping methods that use innovative and rediscovered organic chemistry in high throughput approaches. While this has brought about a leap of progress in this young field, it has also become clear that the different chemistries feature variegated specificity and selectivity. The associated error rates, e.g., in terms of false positives and false negatives, are in large part inherent to the chemistry employed. This means that even assuming technically perfect execution, the interpretation of mapping results issuing from the application of such chemistries are limited by intrinsic features of chemical reactivity. An important but often ignored fact is that the huge stochiometric excess of unmodified over-modified nucleotides is not inert to any of the reagents employed. Consequently, any reaction aimed at chemical discrimination of modified versus unmodified nucleotides has optimal conditions for selectivity that are ultimately anchored in relative reaction rates, whose ratio imposes intrinsic limits to selectivity. Here chemical reactivities of canonical and modified ribonucleosides are revisited as a basis for an understanding of the limits of selectivity achievable with chemical methods.
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Affiliation(s)
- Mark Helm
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-Universität, Staudingerweg 5, D-55128, Mainz, Germany
| | - Martina C Schmidt-Dengler
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-Universität, Staudingerweg 5, D-55128, Mainz, Germany
| | - Marlies Weber
- Institute of Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-Universität, Staudingerweg 5, D-55128, Mainz, Germany
| | - Yuri Motorin
- Université de Lorraine, CNRS, INSERM, UMS2008/US40 IBSLor, EpiRNA-Seq Core facility, Nancy, F-54000, France.,Université de Lorraine, CNRS, UMR7365 IMoPA, Nancy, F-54000, France
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5
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Isokallio MA, Stewart JB. High-Throughput Detection of mtDNA Mutations Leading to tRNA Processing Errors. Methods Mol Biol 2021; 2192:117-132. [PMID: 33230770 DOI: 10.1007/978-1-0716-0834-0_10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Some mutations in the tRNA genes of mitochondrial DNA (mtDNA) have been demonstrated to affect the processing of the mitochondrial transcriptome in human patients with mitochondrial disease. A recent analysis of mtDNA mutations in 527 human tumors revealed that approximately a quarter of the somatic mt-tRNA gene mutations lead to aberrant processing of the mitochondrial transcriptome in these tumors. Here, we describe a method, based on mtDNA mutations induced by the mtDNA mutator mouse, to map the sites that lead to transcript processing abnormalities. Mutations in the mtDNA are identified and quantified by amplicon-based mtDNA sequencing, and compared to the allelic ratios observed in matched RNASeq data. Strong deviation in the variant allele frequencies between the amplicon and RNASeq data suggests that such mutations lead to disruptions in mitochondrial transcript processing.
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Abstract
BACKGROUND Given the etiologic heterogeneity of disease classification using clinical phenomenology, we employed contemporary criteria to classify variants associated with myoclonic epilepsy with ragged-red fibers (MERRF) syndrome and to assess the strength of evidence of gene-disease associations. Standardized approaches are used to clarify the definition of MERRF, which is essential for patient diagnosis, patient classification, and clinical trial design. METHODS Systematic literature and database search with application of standardized assessment of gene-disease relationships using modified Smith criteria and of variants reported to be associated with MERRF using modified Yarham criteria. RESULTS Review of available evidence supports a gene-disease association for two MT-tRNAs and for POLG. Using modified Smith criteria, definitive evidence of a MERRF gene-disease association is identified for MT-TK. Strong gene-disease evidence is present for MT-TL1 and POLG. Functional assays that directly associate variants with oxidative phosphorylation impairment were critical to mtDNA variant classification. In silico analysis was of limited utility to the assessment of individual MT-tRNA variants. With the use of contemporary classification criteria, several mtDNA variants previously reported as pathogenic or possibly pathogenic are reclassified as neutral variants. CONCLUSIONS MERRF is primarily an MT-TK disease, with pathogenic variants in this gene accounting for ~90% of MERRF patients. Although MERRF is phenotypically and genotypically heterogeneous, myoclonic epilepsy is the clinical feature that distinguishes MERRF from other categories of mitochondrial disorders. Given its low frequency in mitochondrial disorders, myoclonic epilepsy is not explained simply by an impairment of cellular energetics. Although MERRF phenocopies can occur in other genes, additional data are needed to establish a MERRF disease-gene association. This approach to MERRF emphasizes standardized classification rather than clinical phenomenology, thus improving patient diagnosis and clinical trial design.
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Huebbers CU, Adam AC, Preuss SF, Schiffer T, Schilder S, Guntinas-Lichius O, Schmidt M, Klussmann JP, Wiesner RJ. High glucose uptake unexpectedly is accompanied by high levels of the mitochondrial ß-F1-ATPase subunit in head and neck squamous cell carcinoma. Oncotarget 2016; 6:36172-84. [PMID: 26452026 PMCID: PMC4742169 DOI: 10.18632/oncotarget.5459] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 09/24/2015] [Indexed: 12/13/2022] Open
Abstract
A hallmark of solid tumors is the consumption of large amounts of glucose and production of lactate, also known as Warburg-like metabolism. This metabolic phenotype is typical for aggressive tumor growth, and can be visualized by 18F-fluorodeoxyglucose (18F-FDG) uptake detected by positron emission tomography (PET). High 18F-FDG uptake inversely correlates with survival and goes along with reduced expression of the catalytic beta-subunit of the H+-ATP synthase (β-F1-ATPase) in several tumor entities analyzed so far. For this study we characterized a series of 15 head and neck squamous cell carcinoma (HNSCC) by (i) determining 18F-FDG-uptake; (ii) quantitative expression analysis of β-F1-ATPase (Complex V), NDUF-S1 (Complex I) and COX1 (Complex IV) of the mitochondrial electron transport chain (ETC), as well as Hsp60 (mitochondrial mass) and GAPDH (glycolysis) in tumor cells; (iii) sequencing of the mtDNA of representative tumor samples. Whereas high 18F-FDG-uptake also correlates with poor prognosis in HNSCC, it surprisingly is accompanied by high levels of β-F1-ATPase, but not by any of the other analyzed proteins. In conclusion, we here describe a completely new phenotype of metabolic adaptation possibly enabling those tumors with highest levels of β-F1-ATPase to rapidly proliferate even in hypoxic zones, which are typical for HNSCC.
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Affiliation(s)
- Christian U Huebbers
- Jean-Uhrmacher-Institute for Otorhinolaryngological Research, University of Köln, 50924 Köln, Germany
| | - Alexander C Adam
- Department of Pathology, Medical Faculty, University of Köln, 50924 Köln, Germany
| | - Simon F Preuss
- Department of Otolaryngology, Medical Faculty, University of Köln, 50924 Köln, Germany
| | - Theresa Schiffer
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, Medical Faculty, University of Köln, 50931 Köln, Germany
| | - Sarah Schilder
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, Medical Faculty, University of Köln, 50931 Köln, Germany
| | | | - Matthias Schmidt
- Department of Nuclear Medicine, Medical Faculty, University of Köln, 50924 Köln, Germany
| | - Jens P Klussmann
- Department of Otorhinolaryngology, Head and Neck Surgery, University of Giessen, 35385 Giessen, Germany
| | - Rudolf J Wiesner
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, Medical Faculty, University of Köln, 50931 Köln, Germany.,Center for Molecular Medicine Cologne, CMMC, University of Köln, 50931 Köln, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Ageing-associated Diseases (CECAD), 50674 Köln, Germany
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8
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Van Haute L, Pearce SF, Powell CA, D’Souza AR, Nicholls TJ, Minczuk M. Mitochondrial transcript maturation and its disorders. J Inherit Metab Dis 2015; 38:655-80. [PMID: 26016801 PMCID: PMC4493943 DOI: 10.1007/s10545-015-9859-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 04/27/2015] [Accepted: 04/29/2015] [Indexed: 11/03/2022]
Abstract
Mitochondrial respiratory chain deficiencies exhibit a wide spectrum of clinical presentations owing to defective mitochondrial energy production through oxidative phosphorylation. These defects can be caused by either mutations in the mitochondrial DNA (mtDNA) or mutations in nuclear genes coding for mitochondrially-targeted proteins. The underlying pathomechanisms can affect numerous pathways involved in mitochondrial biology including expression of mtDNA-encoded genes. Expression of the mitochondrial genes is extensively regulated at the post-transcriptional stage and entails nucleolytic cleavage of precursor RNAs, RNA nucleotide modifications, RNA polyadenylation, RNA quality and stability control. These processes ensure proper mitochondrial RNA (mtRNA) function, and are regulated by dedicated, nuclear-encoded enzymes. Recent growing evidence suggests that mutations in these nuclear genes, leading to incorrect maturation of RNAs, are a cause of human mitochondrial disease. Additionally, mutations in mtDNA-encoded genes may also affect RNA maturation and are frequently associated with human disease. We review the current knowledge on a subset of nuclear-encoded genes coding for proteins involved in mitochondrial RNA maturation, for which genetic variants impacting upon mitochondrial pathophysiology have been reported. Also, primary pathological mtDNA mutations with recognised effects upon RNA processing are described.
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Affiliation(s)
| | - Sarah F. Pearce
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY UK
| | | | - Aaron R. D’Souza
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY UK
| | - Thomas J. Nicholls
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY UK
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 0XY UK
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9
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Stewart JB, Alaei-Mahabadi B, Sabarinathan R, Samuelsson T, Gorodkin J, Gustafsson CM, Larsson E. Simultaneous DNA and RNA Mapping of Somatic Mitochondrial Mutations across Diverse Human Cancers. PLoS Genet 2015; 11:e1005333. [PMID: 26125550 PMCID: PMC4488357 DOI: 10.1371/journal.pgen.1005333] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/03/2015] [Indexed: 12/30/2022] Open
Abstract
Somatic mutations in the nuclear genome are required for tumor formation, but the functional consequences of somatic mitochondrial DNA (mtDNA) mutations are less understood. Here we identify somatic mtDNA mutations across 527 tumors and 14 cancer types, using an approach that takes advantage of evidence from both genomic and transcriptomic sequencing. We find that there is selective pressure against deleterious coding mutations, supporting that functional mitochondria are required in tumor cells, and also observe a strong mutational strand bias, compatible with endogenous replication-coupled errors as the major source of mutations. Interestingly, while allelic ratios in general were consistent in RNA compared to DNA, some mutations in tRNAs displayed strong allelic imbalances caused by accumulation of unprocessed tRNA precursors. The effect was explained by altered secondary structure, demonstrating that correct tRNA folding is a major determinant for processing of polycistronic mitochondrial transcripts. Additionally, the data suggest that tRNA clusters are preferably processed in the 3′ to 5′ direction. Our study gives insights into mtDNA function in cancer and answers questions regarding mitochondrial tRNA biogenesis that are difficult to address in controlled experimental systems. According to the so-called “tRNA punctuation model”, tRNA processing is key to generating all mature mitochondrial mRNAs. However, the process is difficult to study in vivo, since standard tools for genetic manipulation are not applicable to mitochondria. Here, we circumvent this problem by using a large compendium of naturally occurring genetic perturbations, derived from human tumor sequencing data. We identify somatic mitochondrial mutations across hundreds of human tumors using an approach that simultaneously takes advantage of both genomic and transcriptomic sequencing. This enables us to compare the allele frequency in DNA and RNA for each mutation. Our data reveals that some mutations in mitochondrial tRNAs are associated with strong accumulation of immature tRNA precursors, indicative of impaired tRNA mutaration. We find that intact tRNA secondary structure is a major requirement for correct maturation, and that mutations affecting tRNA folding can impair maturation of not only the affected tRNA, but also neighboring gene transcripts. Mutations in mitochondrial tRNAs underlie a range of disease conditions, and our findings may help to explain why mutations in the same tRNA can present different phenotypes. Our results additionally support that there is selective pressure against mutations affecting oxidative phosphorylation, showing that functional mitochondria are required in many tumor cells.
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Affiliation(s)
| | - Babak Alaei-Mahabadi
- Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Radhakrishnan Sabarinathan
- Center for non-coding RNA in Technology and Health, IKVH, University of Copenhagen, Frederiksberg, Denmark
| | - Tore Samuelsson
- Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Jan Gorodkin
- Center for non-coding RNA in Technology and Health, IKVH, University of Copenhagen, Frederiksberg, Denmark
| | - Claes M. Gustafsson
- Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Erik Larsson
- Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- * E-mail:
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10
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Mustoe AM, Liu X, Lin PJ, Al-Hashimi HM, Fierke CA, Brooks CL. Noncanonical secondary structure stabilizes mitochondrial tRNA(Ser(UCN)) by reducing the entropic cost of tertiary folding. J Am Chem Soc 2015; 137:3592-9. [PMID: 25705930 PMCID: PMC4399864 DOI: 10.1021/ja5130308] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mammalian mitochondrial tRNA(Ser(UCN)) (mt-tRNA(Ser)) and pyrrolysine tRNA (tRNA(Pyl)) fold to near-canonical three-dimensional structures despite having noncanonical secondary structures with shortened interhelical loops that disrupt the conserved tRNA tertiary interaction network. How these noncanonical tRNAs compensate for their loss of tertiary interactions remains unclear. Furthermore, in human mt-tRNA(Ser), lengthening the variable loop by the 7472insC mutation reduces mt-tRNA(Ser) concentration in vivo through poorly understood mechanisms and is strongly associated with diseases such as deafness and epilepsy. Using simulations of the TOPRNA coarse-grained model, we show that increased topological constraints encoded by the unique secondary structure of wild-type mt-tRNA(Ser) decrease the entropic cost of folding by ∼2.5 kcal/mol compared to canonical tRNA, offsetting its loss of tertiary interactions. Further simulations show that the pathogenic 7472insC mutation disrupts topological constraints and hence destabilizes the mutant mt-tRNA(Ser) by ∼0.6 kcal/mol relative to wild-type. UV melting experiments confirm that insertion mutations lower mt-tRNA(Ser) melting temperature by 6-9 °C and increase the folding free energy by 0.8-1.7 kcal/mol in a largely sequence- and salt-independent manner, in quantitative agreement with our simulation predictions. Our results show that topological constraints provide a quantitative framework for describing key aspects of RNA folding behavior and also provide the first evidence of a pathogenic mutation that is due to disruption of topological constraints.
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Affiliation(s)
- Anthony M. Mustoe
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Xin Liu
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Paul J. Lin
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Hashim M. Al-Hashimi
- Departments of Biochemistry and Chemistry, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Carol A. Fierke
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Charles L. Brooks
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109-1055, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
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11
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Imasawa T, Tanaka M, Yamaguchi Y, Nakazato T, Kitamura H, Nishimura M. 7501 T > A mitochondrial DNA variant in a patient with glomerulosclerosis. Ren Fail 2014; 36:1461-5. [PMID: 25088491 DOI: 10.3109/0886022x.2014.945181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The presence of granular swollen epithelial cells (GSECs) in tubular cells was recently reported to be a specific change associated with mitochondrial cytopathy. However, at present, GSEC is not routinely evaluated. We, in this study, present a case of glomerulosclerosis, in which the presence of GSECs should provide us one clue to understand the pathogenesis of its progressive decline of renal function. A 54-year-old Japanese female, who had been diagnosed with Graves' disease, was referred for the examination and treatment of her proteinuria (5.4 g/gCre at the first visit to our hospital). A kidney biopsy showed 28.6% of the glomeruli to be globally sclerosed and 10.7% of the glomeruli to have completely collapsed. However, according to a light microscopic analysis, all other glomeruli showed an almost normal appearance, except for some slight enlargement. Almost 30% of the interstitium was damaged by fibrosis. Characteristically, GSECs were observed in the medulla collecting ducts. Although she had no symptoms of either myopathy or encephalopathy, no history of stroke-like episodes or difficulty in hearing, her serum concentrations of lactate and pyruvate were both elevated. Therefore, mitochondrial DNA sequencing was performed to assess the etiopathogenesis of her nephropathy. Consequently, a homoplasmic 7501 T > A replacement, which has not been previously reported in patients with renal diseases, was detected. This case suggests that the routine evaluation of GSECs can provide important clues to assess the etiopathogenesis of cryptogenic glomerulosclerosis.
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Affiliation(s)
- Toshiyuki Imasawa
- Kidney and Diabetes Center, National Hospital Organization Chiba-East Hospital , Chiba-city, Chiba , Japan
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12
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Ding Y, Huang J. Is mitochondrial tRNA(Ser(UCN)) T7501C mutation associated with cardiovascular disease? Mitochondrial DNA A DNA Mapp Seq Anal 2014; 27:205-8. [PMID: 24491108 DOI: 10.3109/19401736.2014.880891] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mitochondrial DNA mutations are increasingly recognized as an important cause of cardiovascular diseases, point mutations in mitochondrial tRNA genes being the largest group among them. Most recently, mutation at position 7501 in mt-tRNA(Ser(UCN)) gene has been reported to be associated with human cardiovascular diseases including cardiomyopathy, sudden cardiac death (SCD) and Tetralogy of Fallot (TOF). However, its direct pathogenic role remained poorly understood. In this study, we performed an extensive web-based search for the published resources concerning this association. Through the application of bioinformatics tool, we observed that this mutation altered the mt-tRNA(Ser(UCN)) secondary structure, in addition, evolutionary conservation analysis of this mutation indicated that this mutation is highly conserved between different species. Notably, the T7501C mutation belonging to human mitochondrial haplogroup U8a1a1, a rare subgroup of U8, was present only in European population and was absent in Han Chinese population. Taken together, our result indicated that the T7501C mutation may occur infrequently and was probably pathogenic in cardiovascular disease development.
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Affiliation(s)
- Yu Ding
- a Central Laboratory , Hangzhou First People's Hospital , Hangzhou , China .,b Affiliated Hangzhou Hospital, Nanjing Medical University , Hangzhou , China , and
| | - Jinyu Huang
- b Affiliated Hangzhou Hospital, Nanjing Medical University , Hangzhou , China , and.,c Department of Cardiology , Hangzhou First People's Hospital , Hangzhou , China
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Mutai H, Kouike H, Teruya E, Takahashi-Kodomari I, Kakishima H, Taiji H, Usami SI, Okuyama T, Matsunaga T. Systematic analysis of mitochondrial genes associated with hearing loss in the Japanese population: dHPLC reveals a new candidate mutation. BMC MEDICAL GENETICS 2011; 12:135. [PMID: 21989059 PMCID: PMC3207971 DOI: 10.1186/1471-2350-12-135] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 10/12/2011] [Indexed: 11/17/2022]
Abstract
Background Variants of mitochondrial DNA (mtDNA) have been evaluated for their association with hearing loss. Although ethnic background affects the spectrum of mtDNA variants, systematic mutational analysis of mtDNA in Japanese patients with hearing loss has not been reported. Methods Using denaturing high-performance liquid chromatography combined with direct sequencing and cloning-sequencing, Japanese patients with prelingual (N = 54) or postlingual (N = 80) sensorineural hearing loss not having pathogenic mutations of m.1555A > G and m.3243A > G nor GJB2 were subjected to mutational analysis of mtDNA genes (12S rRNA, tRNALeu(UUR), tRNASer(UCN), tRNALys, tRNAHis, tRNASer(AGY), and tRNAGlu). Results We discovered 15 variants in 12S rRNA and one homoplasmic m.7501A > G variant in tRNASer(UCN); no variants were detected in the other genes. Two criteria, namely the low frequency in the controls and the high conservation among animals, selected the m.904C > T and the m.1105T > C variants in 12S rRNA as candidate pathogenic mutations. Alterations in the secondary structures of the two variant transcripts as well as that of m.7501A > G in tRNASer(UCN) were predicted. Conclusions The m.904C > T variant was found to be a new candidate mutation associated with hearing loss. The m.1105T > C variant is unlikely to be pathogenic. The pathogenicity of the homoplasmic m.7501T > A variant awaits further study.
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Affiliation(s)
- Hideki Mutai
- Laboratory of Auditory Disorders, Division of Hearing and Balance Research, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
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Banerjee R, Reynolds NM, Yadavalli SS, Rice C, Roy H, Banerjee P, Alexander RW, Ibba M. Mitochondrial Aminoacyl-tRNA Synthetase Single-Nucleotide Polymorphisms That Lead to Defects in Refolding but Not Aminoacylation. J Mol Biol 2011; 410:280-93. [DOI: 10.1016/j.jmb.2011.05.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Revised: 05/05/2011] [Accepted: 05/06/2011] [Indexed: 12/28/2022]
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Error compensation of tRNA misacylation by codon-anticodon mismatch prevents translational amino acid misinsertion. Comput Biol Chem 2011; 35:81-95. [PMID: 21470914 DOI: 10.1016/j.compbiolchem.2011.03.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 02/22/2011] [Accepted: 03/01/2011] [Indexed: 11/20/2022]
Abstract
Codon-anticodon mismatches and tRNA misloadings cause translational amino acid misinsertions, producing dysfunctional proteins. Here I explore the original hypothesis whether mismatches tend to compensate misacylation, so as to insert the amino acid coded by the codon. This error compensation is promoted by the fact that codon-anticodon mismatch stabilities increase with tRNA misacylation potentials (predicted by 'tfam') by non-cognate amino acids coded by the mismatched codons for most tRNAs examined. Error compensation is independent of preferential misacylation by non-cognate amino acids physico-chemically similar to cognate amino acids, a phenomenon that decreases misinsertion impacts. Error compensation correlates negatively with (a) codon/anticodon abundance (in human mitochondria and Escherichia coli); (b) developmental instability (estimated by fluctuating asymmetry in bilateral counts of subdigital lamellae, in each of two lizard genera, Anolis and Sceloporus); and (c) pathogenicity of human mitochondrial tRNA polymorphisms. Patterns described here suggest that tRNA misacylation is sometimes compensated by codon-anticodon mismatches. Hence translation inserts the amino acid coded by the mismatched codon, despite mismatch and misloading. Results suggest that this phenomenon is sufficiently important to affect whole organism phenotypes, as shown by correlations with pathologies and morphological estimates of developmental stability.
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16
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Pathogenic mutations in antisense mitochondrial tRNAs. J Theor Biol 2011; 269:287-96. [DOI: 10.1016/j.jtbi.2010.11.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 11/02/2010] [Accepted: 11/04/2010] [Indexed: 11/22/2022]
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Yarham JW, Elson JL, Blakely EL, McFarland R, Taylor RW. Mitochondrial tRNA mutations and disease. WILEY INTERDISCIPLINARY REVIEWS-RNA 2010; 1:304-24. [DOI: 10.1002/wrna.27] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- John W. Yarham
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Joanna L. Elson
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Emma L. Blakely
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Robert McFarland
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Robert W. Taylor
- Mitochondrial Research Group, Institute for Ageing and Health, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
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Mitochondrial DNA mutations and human disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:113-28. [PMID: 19761752 DOI: 10.1016/j.bbabio.2009.09.005] [Citation(s) in RCA: 417] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 09/04/2009] [Accepted: 09/09/2009] [Indexed: 01/07/2023]
Abstract
Mitochondrial disorders are a group of clinically heterogeneous diseases, commonly defined by a lack of cellular energy due to oxidative phosphorylation (OXPHOS) defects. Since the identification of the first human pathological mitochondrial DNA (mtDNA) mutations in 1988, significant efforts have been spent in cataloguing the vast array of causative genetic defects of these disorders. Currently, more than 250 pathogenic mtDNA mutations have been identified. An ever-increasing number of nuclear DNA mutations are also being reported as the majority of proteins involved in mitochondrial metabolism and maintenance are nuclear-encoded. Understanding the phenotypic diversity and elucidating the molecular mechanisms at the basis of these diseases has however proved challenging. Progress has been hampered by the peculiar features of mitochondrial genetics, an inability to manipulate the mitochondrial genome, and difficulties in obtaining suitable models of disease. In this review, we will first outline the unique features of mitochondrial genetics before detailing the diseases and their genetic causes, focusing specifically on primary mtDNA genetic defects. The functional consequences of mtDNA mutations that have been characterised to date will also be discussed, along with current and potential future diagnostic and therapeutic advances.
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19
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The rat mitochondrial Ori L encodes a novel small RNA resembling an ancestral tRNA. Biochem Biophys Res Commun 2008; 372:634-8. [PMID: 18514058 DOI: 10.1016/j.bbrc.2008.05.092] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Accepted: 05/16/2008] [Indexed: 11/21/2022]
Abstract
The RNA minihelix, a proposed tRNA precursor, exhibits tRNA-like properties. Sequence-specific RNA minihelices can inhibit cell growth probably due to their binding to the cognate tRNA and naturally occurring non-tRNA substrates for aminoacylation may serve a similar purpose. Thus far, no natural RNA minihelices have been found. In the present study, we found a novel small RNA of 32 nucleotides, which is expressed abundantly in all rat tissues tested. Distinct from all of known endogenous small RNAs, this small RNA (temporarily named as tpl-sRNA) can form an RNA minihelix containing a stem-loop domain followed by ACCA. tpl-sRNA is encoded by the light-strand replication origin (Ori L) of the rat mitochondrial genome, and the 3'-terminal CCA of tpl-sRNA is post-transcriptionally added. Moreover, tpl-sRNA is chargeable in vivo. Our study demonstrates for the first time an endogenous small RNA that resembles an ancestral tRNA and exhibits some tRNA-like properties in mammals.
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20
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Hornig-Do HT, von Kleist-Retzow JC, Lanz K, Wickenhauser C, Kudin AP, Kunz WS, Wiesner RJ, Schauen M. Human epidermal keratinocytes accumulate superoxide due to low activity of Mn-SOD, leading to mitochondrial functional impairment. J Invest Dermatol 2006; 127:1084-93. [PMID: 17185981 DOI: 10.1038/sj.jid.5700666] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The energy metabolism of the epidermis has been the subject of controversy; thus we characterized the mitochondrial phenotype of human primary keratinocytes and fibroblasts, in cell culture and in human skin sections. We found that keratinocytes respire as much as fibroblasts, however, maximal activities of the respiratory chain (RC) complexes were 2- to 5-fold lower, whereas expression levels of RC proteins were similar. Maximal activities of aconitase and isocitrate dehydrogenase, two mitochondrial enzymes especially vulnerable to superoxide, were lower than in fibroblasts. Indeed, superoxide anion levels were much higher in keratinocytes, and keratinocytes displayed higher lipid peroxidation levels and a lower reduced glutathione/oxidized glutathione ratio, indicating enhanced oxidative stress. Although superoxide dismutase activity and especially expression of the mitochondrial superoxide dismutase, Mn-SOD, were drastically lower in keratinocytes, explaining the high superoxide levels, glutathione peroxidase activity and protein were almost undetectable in fibroblasts. Catalase activity and hydrogen peroxide levels were similar. In summary, we could show that keratinocytes actively use the mitochondrial RC not only for adenosine 5' triphosphate synthesis but also for the accumulation of superoxide anions, even at the expense of mitochondrial functional capacity, indicating that superoxide-driven mitochondrial impairment might be a prerequisite for keratinocyte differentiation.
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Young WY, Zhao L, Qian Y, Li R, Chen J, Yuan H, Dai P, Zhai S, Han D, Guan MX. Variants in mitochondrial tRNAGlu, tRNAArg, and tRNAThr may influence the phenotypic manifestation of deafness-associated 12S rRNA A1555G mutation in three Han Chinese families with hearing loss. Am J Med Genet A 2006; 140:2188-97. [PMID: 16955413 DOI: 10.1002/ajmg.a.31434] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We report here on the clinical, genetic, and molecular characterization of three Han Chinese pedigrees with aminoglycoside-induced and nonsyndromic hearing loss. Clinical evaluation revealed the variable phenotype of hearing loss including severity, age-at-onset, audiometric configuration in these subjects. Penetrances of hearing loss in BJ107, BJ108, and BJ109 pedigrees are 35%, 63%, and 67%, respectively. Mutational analysis of the complete mitochondrial genomes in these pedigrees showed the identical homoplasmic A1555G mutation and distinct sets of mitochondrial DNA (mtDNA) variants belonging to haplogroups N, F, and M, respectively. Of these variants, the A14693G mutation in the tRNA(Glu), the T15908C mutation in the tRNA(Thr), and the T10454C mutation in the tRNA(Arg) are of special interest as these mutations occur at positions which are highly evolutionarily conserved nucleotides of corresponding tRNAs. These homoplasmic mtDNA mutations were absent among 156 unrelated Chinese controls. The A14693G and T10454C mutations occur at the highly conserved bases of the TpsiC-loop of tRNA(Glu) and tRNA(Arg), respectively. Furthermore, the T15908C mutation in the tRNA(Thr) disrupts a highly conserved A-U base-pairing at the D-stem of this tRNA. The alteration of structure of these tRNAs by these mtDNA mutations may lead to a failure in tRNA metabolism, thereby causing impairment of mitochondrial translation. Thus, mitochondrial dysfunctions, caused by the A1555G mutation, would be worsened by these mtDNA mutations. Therefore, these mtDNA mutations may have a potential modifier role in increasing the penetrance and expressivity of the deafness-associated 12S rRNA A1555G mutation in those Chinese pedigrees.
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Affiliation(s)
- Wie-Yen Young
- Institute of Otolaryngology, Chinese PLA General Hospital, Beijing, China
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22
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Maniura-Weber K, Helm M, Engemann K, Eckertz S, Möllers M, Schauen M, Hayrapetyan A, von Kleist-Retzow JC, Lightowlers RN, Bindoff LA, Wiesner RJ. Molecular dysfunction associated with the human mitochondrial 3302A>G mutation in the MTTL1 (mt-tRNALeu(UUR)) gene. Nucleic Acids Res 2006; 34:6404-15. [PMID: 17130166 PMCID: PMC1702489 DOI: 10.1093/nar/gkl727] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The gene encoding mt-tRNALeu(UUR), MT-TL1, is a hotspot for pathogenic mtDNA mutations. Amongst the first to be described was the 3302A>G transition which resulted in a substantial accumulation in patient muscle of RNA19, an unprocessed RNA intermediate including mt-16S rRNA, mt-tRNALeu(UUR) and MTND1. We have now been able to further assess the molecular aetiology associated with 3302A>G in transmitochondrial cybrids. Increased steady-state levels of RNA19 was confirmed, although not to the levels previously reported in muscle. This data was consistent with an increase in RNA19 stability. The mutation resulted in decreased mt-tRNALeu(UUR) levels, but its stability was unchanged, consistent with a defect in RNA19 processing responsible for low tRNA levels. A partial defect in aminoacylation was also identified, potentially caused by an alteration in tRNA structure. These deficiencies lead to a severe defect in respiration in the transmitochondrial cybrids, consistent with the profound mitochondrial disorder originally associated with this mutation.
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Affiliation(s)
- Katharina Maniura-Weber
- Institute of Vegetative Physiology, Medical Faculty, University of KölnRobert-Koch-Strasse 39, D-50931 Köln, Germany
| | - Mark Helm
- Institute of Pharmacy and Molecular Biotechnology, University of HeidelbergIm Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Katrin Engemann
- Institute of Vegetative Physiology, Medical Faculty, University of KölnRobert-Koch-Strasse 39, D-50931 Köln, Germany
| | - Sabrina Eckertz
- Institute of Vegetative Physiology, Medical Faculty, University of KölnRobert-Koch-Strasse 39, D-50931 Köln, Germany
| | - Myriam Möllers
- Institute of Vegetative Physiology, Medical Faculty, University of KölnRobert-Koch-Strasse 39, D-50931 Köln, Germany
| | - Matthias Schauen
- Institute of Vegetative Physiology, Medical Faculty, University of KölnRobert-Koch-Strasse 39, D-50931 Köln, Germany
| | - Armine Hayrapetyan
- Institute of Pharmacy and Molecular Biotechnology, University of HeidelbergIm Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Jürgen-Christoph von Kleist-Retzow
- Center for Molecular Medicine Cologne (CMMC), University of KölnJoseph-Stelzmann-Strasse 52, 50931 Köln, Germany
- Department of Pediatrics, University of KölnKerpener Strasse 62, 50924 Köln, Germany
| | - Robert N. Lightowlers
- School of Neurology, Neurobiology and Psychiatry, Medical School, University of Newcastle upon TyneUK
| | - Laurence A. Bindoff
- Department of Neurology, Institute of Clinical Medicine, Haukeland University Hospital, University of Bergen5021 Bergen, Norway
- To whom correspondence should be addressed. Tel: +49 221 478 3610; Fax: +49 221 478 3538;
| | - Rudolf J. Wiesner
- Institute of Vegetative Physiology, Medical Faculty, University of KölnRobert-Koch-Strasse 39, D-50931 Köln, Germany
- Center for Molecular Medicine Cologne (CMMC), University of KölnJoseph-Stelzmann-Strasse 52, 50931 Köln, Germany
- To whom correspondence should be addressed. Tel: +49 221 478 3610; Fax: +49 221 478 3538;
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Montoya J, López-Pérez MJ, Ruiz-Pesini E. Mitochondrial DNA transcription and diseases: past, present and future. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2006; 1757:1179-89. [PMID: 16697348 DOI: 10.1016/j.bbabio.2006.03.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 03/21/2006] [Accepted: 03/31/2006] [Indexed: 11/25/2022]
Abstract
The transcription of mitochondrial DNA has been studied for 30 years. However, many of the earlier observations are still unsolved. In this review we will recall the basis of mitochondrial DNA transcription, established more than twenty years ago, will include some of the recent progress in the understanding of this process and will suggest hypotheses for some of the unexplained topics. Moreover, we will show some examples of mitochondrial pathology due to altered transcription and RNA metabolism.
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Affiliation(s)
- Julio Montoya
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza-Instituto Aragonés de Ciencias de la Salud, Miguel Servet 177, 50013-Zaragoza, Spain.
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