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Bakare AB, Lesnefsky EJ, Iyer S. Leigh Syndrome: A Tale of Two Genomes. Front Physiol 2021; 12:693734. [PMID: 34456746 PMCID: PMC8385445 DOI: 10.3389/fphys.2021.693734] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 07/22/2021] [Indexed: 12/21/2022] Open
Abstract
Leigh syndrome is a rare, complex, and incurable early onset (typically infant or early childhood) mitochondrial disorder with both phenotypic and genetic heterogeneity. The heterogeneous nature of this disorder, based in part on the complexity of mitochondrial genetics, and the significant interactions between the nuclear and mitochondrial genomes has made it particularly challenging to research and develop therapies. This review article discusses some of the advances that have been made in the field to date. While the prognosis is poor with no current substantial treatment options, multiple studies are underway to understand the etiology, pathogenesis, and pathophysiology of Leigh syndrome. With advances in available research tools leading to a better understanding of the mitochondria in health and disease, there is hope for novel treatment options in the future.
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Affiliation(s)
- Ajibola B. Bakare
- Department of Biological Sciences, J. William Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, AR, United States
| | - Edward J. Lesnefsky
- Division of Cardiology, Pauley Heart Center, Department of Internal Medicine, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
- Department of Physiology/Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
- Department of Biochemistry and Molecular Biology, School of Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Shilpa Iyer
- Department of Biological Sciences, J. William Fulbright College of Arts and Sciences, University of Arkansas, Fayetteville, AR, United States
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2
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Friedlander JE, Shen N, Zeng A, Korm S, Feng H. Failure to Guard: Mitochondrial Protein Quality Control in Cancer. Int J Mol Sci 2021; 22:ijms22158306. [PMID: 34361072 PMCID: PMC8348654 DOI: 10.3390/ijms22158306] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/20/2021] [Accepted: 07/27/2021] [Indexed: 02/07/2023] Open
Abstract
Mitochondria are energetic and dynamic organelles with a crucial role in bioenergetics, metabolism, and signaling. Mitochondrial proteins, encoded by both nuclear and mitochondrial DNA, must be properly regulated to ensure proteostasis. Mitochondrial protein quality control (MPQC) serves as a critical surveillance system, employing different pathways and regulators as cellular guardians to ensure mitochondrial protein quality and quantity. In this review, we describe key pathways and players in MPQC, such as mitochondrial protein translocation-associated degradation, mitochondrial stress responses, chaperones, and proteases, and how they work together to safeguard mitochondrial health and integrity. Deregulated MPQC leads to proteotoxicity and dysfunctional mitochondria, which contributes to numerous human diseases, including cancer. We discuss how alterations in MPQC components are linked to tumorigenesis, whether they act as drivers, suppressors, or both. Finally, we summarize recent advances that seek to target these alterations for the development of anti-cancer drugs.
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Affiliation(s)
- Joseph E. Friedlander
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
| | - Ning Shen
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
- Department of Medicine, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Aozhuo Zeng
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
| | - Sovannarith Korm
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
| | - Hui Feng
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
- Department of Medicine, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA 02118, USA
- Correspondence: ; Tel.: +1-617-358-4688; Fax: +1-617-358-1599
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3
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Exploring the Ability of LARS2 Carboxy-Terminal Domain in Rescuing the MELAS Phenotype. Life (Basel) 2021; 11:life11070674. [PMID: 34357047 PMCID: PMC8303833 DOI: 10.3390/life11070674] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/06/2021] [Accepted: 07/08/2021] [Indexed: 12/25/2022] Open
Abstract
The m.3243A>G mutation within the mitochondrial mt-tRNALeu(UUR) gene is the most prevalent variant linked to mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome. This pathogenic mutation causes severe impairment of mitochondrial protein synthesis due to alterations of the mutated tRNA, such as reduced aminoacylation and a lack of post-transcriptional modification. In transmitochondrial cybrids, overexpression of human mitochondrial leucyl-tRNA synthetase (LARS2) has proven effective in rescuing the phenotype associated with m.3243A>G substitution. The rescuing activity resides in the carboxy-terminal domain (Cterm) of the enzyme; however, the precise molecular mechanisms underlying this process have not been fully elucidated. To deepen our knowledge on the rescuing mechanisms, we demonstrated the interactions of the Cterm with mutated mt-tRNALeu(UUR) and its precursor in MELAS cybrids. Further, the effect of Cterm expression on mitochondrial functions was evaluated. We found that Cterm ameliorates de novo mitochondrial protein synthesis, whilst it has no effect on mt-tRNALeu(UUR) steady-state levels and aminoacylation. Despite the complete recovery of cell viability and the increase in mitochondrial translation, Cterm-overexpressing cybrids were not able to recover bioenergetic competence. These data suggest that, in our MELAS cell model, the beneficial effect of Cterm may be mediated by factors that are independent of the mitochondrial bioenergetics.
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Richter U, McFarland R, Taylor RW, Pickett SJ. The molecular pathology of pathogenic mitochondrial tRNA variants. FEBS Lett 2021; 595:1003-1024. [PMID: 33513266 PMCID: PMC8600956 DOI: 10.1002/1873-3468.14049] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/14/2021] [Accepted: 01/18/2021] [Indexed: 12/16/2022]
Abstract
Mitochondrial diseases are clinically and genetically heterogeneous disorders, caused by pathogenic variants in either the nuclear or mitochondrial genome. This heterogeneity is particularly striking for disease caused by variants in mitochondrial DNA-encoded tRNA (mt-tRNA) genes, posing challenges for both the treatment of patients and understanding the molecular pathology. In this review, we consider disease caused by the two most common pathogenic mt-tRNA variants: m.3243A>G (within MT-TL1, encoding mt-tRNALeu(UUR) ) and m.8344A>G (within MT-TK, encoding mt-tRNALys ), which together account for the vast majority of all mt-tRNA-related disease. We compare and contrast the clinical disease they are associated with, as well as their molecular pathologies, and consider what is known about the likely molecular mechanisms of disease. Finally, we discuss the role of mitochondrial-nuclear crosstalk in the manifestation of mt-tRNA-associated disease and how research in this area not only has the potential to uncover molecular mechanisms responsible for the vast clinical heterogeneity associated with these variants but also pave the way to develop treatment options for these devastating diseases.
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Affiliation(s)
- Uwe Richter
- Wellcome Centre for Mitochondrial ResearchThe Medical SchoolNewcastle UniversityUK
- Molecular and Integrative Biosciences Research ProgrammeFaculty of Biological and Environmental SciencesUniversity of HelsinkiFinland
- Newcastle University Biosciences InstituteNewcastle UniversityUK
| | - Robert McFarland
- Wellcome Centre for Mitochondrial ResearchThe Medical SchoolNewcastle UniversityUK
- Newcastle University Translational and Clinical Research InstituteNewcastle UniversityUK
| | - Robert W. Taylor
- Wellcome Centre for Mitochondrial ResearchThe Medical SchoolNewcastle UniversityUK
- Newcastle University Translational and Clinical Research InstituteNewcastle UniversityUK
| | - Sarah J. Pickett
- Wellcome Centre for Mitochondrial ResearchThe Medical SchoolNewcastle UniversityUK
- Newcastle University Translational and Clinical Research InstituteNewcastle UniversityUK
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5
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Abstract
Systematics is described for annotation of variations in RNA molecules. The conceptual framework is part of Variation Ontology (VariO) and facilitates depiction of types of variations, their functional and structural effects and other consequences in any RNA molecule in any organism. There are more than 150 RNA related VariO terms in seven levels, which can be further combined to generate even more complicated and detailed annotations. The terms are described together with examples, usually for variations and effects in human and in diseases. RNA variation type has two subcategories: variation classification and origin with subterms. Altogether six terms are available for function description. Several terms are available for affected RNA properties. The ontology contains also terms for structural description for affected RNA type, post-transcriptional RNA modifications, secondary and tertiary structure effects and RNA sugar variations. Together with the DNA and protein concepts and annotations, RNA terms allow comprehensive description of variations of genetic and non-genetic origin at all possible levels. The VariO annotations are readable both for humans and computer programs for advanced data integration and mining.
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Affiliation(s)
- Mauno Vihinen
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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6
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Bruni F, Proctor-Kent Y, Lightowlers RN, Chrzanowska-Lightowlers ZM. Messenger RNA delivery to mitoribosomes - hints from a bacterial toxin. FEBS J 2020; 288:437-451. [PMID: 32329962 PMCID: PMC7891357 DOI: 10.1111/febs.15342] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 04/06/2020] [Accepted: 04/21/2020] [Indexed: 11/28/2022]
Abstract
In mammalian mitochondria, messenger RNA is processed and matured from large primary transcripts in structures known as RNA granules. The identity of the factors and process transferring the matured mRNA to the mitoribosome for translation is unclear. Nascent mature transcripts are believed to associate initially with the small mitoribosomal subunit prior to recruitment of the large subunit to form the translationally active monosome. When the small subunit fails to assemble, however, the stability of mt‐mRNA is only marginally affected, and under these conditions, the LRPPRC/SLIRP RNA‐binding complex has been implicated in maintaining mt‐mRNA stability. Here, we exploit the activity of a bacterial ribotoxin, VapC20, to show that in the absence of the large mitoribosomal subunit, mt‐mRNA species are selectively lost. Further, if the small subunit is also depleted, the mt‐mRNA levels are recovered. As a consequence of these data, we suggest a natural pathway for loading processed mt‐mRNA onto the mitoribosome.
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Affiliation(s)
- Francesco Bruni
- The Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, UK.,Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari Aldo Moro, Italy
| | - Yasmin Proctor-Kent
- The Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, UK
| | - Robert N Lightowlers
- The Wellcome Centre for Mitochondrial Research, Institute for Cell and Molecular Biosciences, Newcastle University, UK
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Perli E, Pisano A, Pignataro MG, Campese AF, Pelullo M, Genovese I, de Turris V, Ghelli AM, Cerbelli B, Giordano C, Colotti G, Morea V, d'Amati G. Exogenous peptides are able to penetrate human cell and mitochondrial membranes, stabilize mitochondrial tRNA structures, and rescue severe mitochondrial defects. FASEB J 2020; 34:7675-7686. [PMID: 32304340 DOI: 10.1096/fj.201903270r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 03/04/2020] [Accepted: 03/24/2020] [Indexed: 12/14/2022]
Abstract
Mutations in mitochondrial transfer RNA (mt-tRNA) genes are responsible for a wide range of syndromes, for which no effective treatment is available. We previously reported that transfection of the nucleotide sequence encoding for the 16-residue β32_33 peptide from mitochondrial leucyl-tRNA synthetase ameliorates the cell phenotype caused by the mitochondrial tRNA mutations. In this work, we demonstrated that both the β32_33 peptide linked with the known (L)-Phe-(D)-Arg-(L)-Phe-(L)-Lys (FrFK) mitochondrial penetrating sequence and, strikingly, the β32_33 peptide per se, are able to penetrate both the plasma and mitochondrial membranes and exert the rescuing activity when exogenously administered to cells bearing the mutations m.3243A > G and m.8344A > G. These mutations are responsible for the most common and severe mt-tRNA-related diseases. In addition, we dissected the molecular determinants of constructs activity by showing that both the order of amino acids along the sequence and presence of positive charges are essential determinants of the peptide activity in cells and mt-tRNA structures stabilization in vitro. In view of future in vivo studies, this information may be required to design of β32_33 peptide-mimetic derivatives. The β32_33 and FrFK-β32_33 peptides are, therefore, promising molecules for the development of therapeutic agents against diseases caused by the mt-tRNA point mutations.
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Affiliation(s)
- Elena Perli
- Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome, Rome, Italy
| | - Annalinda Pisano
- Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome, Rome, Italy
| | - Maria Gemma Pignataro
- Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome, Rome, Italy
| | | | - Maria Pelullo
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
| | - Ilaria Genovese
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome, Italy
| | - Valeria de Turris
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
| | - Anna Maria Ghelli
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, Italy
| | - Bruna Cerbelli
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University, Latina, Italy
| | - Carla Giordano
- Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome, Rome, Italy
| | - Gianni Colotti
- Institute of Molecular Biology and Pathology, National Research Council of Italy, Rome, Italy
| | - Veronica Morea
- Institute of Molecular Biology and Pathology, National Research Council of Italy, Rome, Italy
| | - Giulia d'Amati
- Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome, Rome, Italy
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8
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Interpretation of mitochondrial tRNA variants. Genet Med 2020; 22:917-926. [PMID: 31965079 DOI: 10.1038/s41436-019-0746-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/26/2019] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To develop criteria to interpret mitochondrial transfer RNA (mt-tRNA) variants based on unique characteristics of mitochondrial genetics and conserved structural/functional properties of tRNA. METHODS We developed rules on a set of established pathogenic/benign variants by examining heteroplasmy correlations with phenotype, tissue distribution, family members, and among unrelated families from published literature. We validated these deduced rules using our new cases and applied them to classify novel variants. RESULTS Evaluation of previously reported pathogenic variants found that 80.6% had sufficient evidence to support phenotypic correlation with heteroplasmy levels among and within families. The remaining variants were downgraded due to the lack of similar evidence. Application of the verified criteria resulted in rescoring 80.8% of reported variants of uncertain significance (VUS) to benign and likely benign. Among 97 novel variants, none met pathogenic criteria. A large proportion of novel variants (84.5%) remained as VUS, while only 10.3% were likely pathogenic. Detection of these novel variants in additional individuals would facilitate their classification. CONCLUSION Proper interpretation of mt-tRNA variants is crucial for accurate clinical diagnosis and genetic counseling. Correlations with tissue distribution, heteroplasmy levels, predicted perturbations to tRNA structure, and phenotypes provide important evidence for determining the clinical significance of mt-tRNA variants.
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Gong S, Wang X, Meng F, Cui L, Yi Q, Zhao Q, Cang X, Cai Z, Mo JQ, Liang Y, Guan MX. Overexpression of mitochondrial histidyl-tRNA synthetase restores mitochondrial dysfunction caused by a deafness-associated tRNAHis mutation. J Biol Chem 2020. [DOI: 10.1016/s0021-9258(17)49906-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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10
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Gong S, Wang X, Meng F, Cui L, Yi Q, Zhao Q, Cang X, Cai Z, Mo JQ, Liang Y, Guan MX. Overexpression of mitochondrial histidyl-tRNA synthetase restores mitochondrial dysfunction caused by a deafness-associated tRNA His mutation. J Biol Chem 2019; 295:940-954. [PMID: 31819004 DOI: 10.1074/jbc.ra119.010998] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/27/2019] [Indexed: 01/19/2023] Open
Abstract
The deafness-associated m.12201T>C mutation affects the A5-U68 base-pairing within the acceptor stem of mitochondrial tRNAHis The primary defect in this mutation is an alteration in tRNAHis aminoacylation. Here, we further investigate the molecular mechanism of the deafness-associated tRNAHis 12201T>C mutation and test whether the overexpression of the human mitochondrial histidyl-tRNA synthetase gene (HARS2) in cytoplasmic hybrid (cybrid) cells carrying the m.12201T>C mutation reverses mitochondrial dysfunctions. Using molecular dynamics simulations, we demonstrate that the m.12201T>C mutation perturbs the tRNAHis structure and function, supported by decreased melting temperature, conformational changes, and instability of mutated tRNA. We show that the m.12201T>C mutation-induced alteration of aminoacylation tRNAHis causes mitochondrial translational defects and respiratory deficiency. We found that the transfer of HARS2 into the cybrids carrying the m.12201T>C mutation raises the levels of aminoacylated tRNAHis from 56.3 to 75.0% but does not change the aminoacylation of other tRNAs. Strikingly, HARS2 overexpression increased the steady-state levels of tRNAHis and of noncognate tRNAs, including tRNAAla, tRNAGln, tRNAGlu, tRNALeu(UUR), tRNALys, and tRNAMet, in cells bearing the m.12201T>C mutation. This improved tRNA metabolism elevated the efficiency of mitochondrial translation, activities of oxidative phosphorylation complexes, and respiration capacity. Furthermore, HARS2 overexpression markedly increased mitochondrial ATP levels and membrane potential and reduced production of reactive oxygen species in cells carrying the m.12201T>C mutation. These results indicate that HARS2 overexpression corrects the mitochondrial dysfunction caused by the tRNAHis mutation. These findings provide critical insights into the pathophysiology of mitochondrial disease and represent a step toward improved therapeutic interventions for mitochondrial disorders.
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Affiliation(s)
- Shasha Gong
- Taizhou University Hospital, Taizhou University, Taizhou, Zhejiang 318000, China.,Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xiaoqiong Wang
- Department of Otolaryngology, Taizhou Municipal Hospital, Taizhou, Zhejiang 318000, China.,Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Feilong Meng
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China.,Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Limei Cui
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Qiuzi Yi
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Qiong Zhao
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xiaohui Cang
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Zhiyi Cai
- Department of Otolaryngology, Taizhou Municipal Hospital, Taizhou, Zhejiang 318000, China
| | - Jun Qin Mo
- Department of Pathology, Rady Children's Hospital, University of California School of Medicine, San Diego, California 92123
| | - Yong Liang
- Taizhou University Hospital, Taizhou University, Taizhou, Zhejiang 318000, China
| | - Min-Xin Guan
- Institute of Genetics, Zhejiang University, Hangzhou, Zhejiang 310058, China .,Division of Medical Genetics and Genomics, the Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Key Laboratory of Reproductive Genetics, Ministry of Education of PRC, Zhejiang University, Hangzhou, Zhejiang 310058, China.,Joint Institute of Genetics and Genomic Medicine between Zhejiang University and University of Toronto, Hangzhou, Zhejiang 310058, China
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11
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Toompuu M, Tuomela T, Laine P, Paulin L, Dufour E, Jacobs HT. Polyadenylation and degradation of structurally abnormal mitochondrial tRNAs in human cells. Nucleic Acids Res 2019. [PMID: 29518244 PMCID: PMC6007314 DOI: 10.1093/nar/gky159] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
RNA 3' polyadenylation is known to serve diverse purposes in biology, in particular, regulating mRNA stability and translation. Here we determined that, upon exposure to high levels of the intercalating agent ethidium bromide (EtBr), greater than those required to suppress mitochondrial transcription, mitochondrial tRNAs in human cells became polyadenylated. Relaxation of the inducing stress led to rapid turnover of the polyadenylated tRNAs. The extent, kinetics and duration of tRNA polyadenylation were EtBr dose-dependent, with mitochondrial tRNAs differentially sensitive to the stress. RNA interference and inhibitor studies indicated that ongoing mitochondrial ATP synthesis, plus the mitochondrial poly(A) polymerase and SUV3 helicase were required for tRNA polyadenylation, while polynucleotide phosphorylase counteracted the process and was needed, along with SUV3, for degradation of the polyadenylated tRNAs. Doxycycline treatment inhibited both tRNA polyadenylation and turnover, suggesting a possible involvement of the mitoribosome, although other translational inhibitors had only minor effects. The dysfunctional tRNALeu(UUR) bearing the pathological A3243G mutation was constitutively polyadenylated at a low level, but this was markedly enhanced after doxycycline treatment. We propose that polyadenylation of structurally and functionally abnormal mitochondrial tRNAs entrains their PNPase/SUV3-mediated destruction, and that this pathway could play an important role in mitochondrial diseases associated with tRNA mutations.
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Affiliation(s)
- Marina Toompuu
- Faculty of Medicine and Life Sciences, BioMediTech Institute and Tampere University Hospital, FI-33014 University of Tampere, Finland
| | - Tea Tuomela
- Faculty of Medicine and Life Sciences, BioMediTech Institute and Tampere University Hospital, FI-33014 University of Tampere, Finland
| | - Pia Laine
- Institute of Biotechnology, FI-00014 University of Helsinki, Finland
| | - Lars Paulin
- Institute of Biotechnology, FI-00014 University of Helsinki, Finland
| | - Eric Dufour
- Faculty of Medicine and Life Sciences, BioMediTech Institute and Tampere University Hospital, FI-33014 University of Tampere, Finland
| | - Howard T Jacobs
- Faculty of Medicine and Life Sciences, BioMediTech Institute and Tampere University Hospital, FI-33014 University of Tampere, Finland.,Institute of Biotechnology, FI-00014 University of Helsinki, Finland
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Uittenbogaard M, Wang H, Zhang VW, Wong LJ, Brantner CA, Gropman A, Chiaramello A. The nuclear background influences the penetrance of the near-homoplasmic m.1630 A > G MELAS variant in a symptomatic proband and asymptomatic mother. Mol Genet Metab 2019; 126:429-438. [PMID: 30709774 PMCID: PMC6773428 DOI: 10.1016/j.ymgme.2019.01.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 01/17/2023]
Abstract
In this study, we report the metabolic consequences of the m.1630 A > G variant in fibroblasts from the symptomatic proband affected with the mitochondrial encephalomyopathy lactic acidosis and stroke-like episode Syndrome and her asymptomatic mother. By long-range PCR followed by massively parallel sequencing of the mitochondrial genome, we accurately measured heteroplasmy in fibroblasts from the proband (89.6%) and her mother (94.8%). Using complementary experimental approaches, we show a functional correlation between manifestation of clinical symptoms and bioenergetic potential. Our mitochondrial morphometric analysis reveals a link between defects of mitochondrial cristae ultrastructure and symptomatic status. Despite near-homoplasmic level of the m.1630A > G variant, the mother's fibroblasts have a normal OXPHOS metabolism, which stands in contrast to the severely impaired OXPHOS response of the proband's fibroblasts. The proband's fibroblasts also exhibit glycolysis at near constitutive levels resulting in a stunted compensatory glycolytic response to offset the severe OXPHOS defect. Whole exome sequencing reveals the presence of a heterozygous nonsense VARS2 variant (p.R334X) exclusively in the proband, which removes two thirds of the VARS2 protein containing key domains interacting with the mt-tRNAval and may play a role in modulating the penetrance of the m.1630A > G variant despite similar near homoplasmic levels. Our transmission electron microscopy study also shows unexpected ultrastructural changes of chromatin suggestive of differential epigenomic regulation between the proband and her mother that may explain the differential OXPHOS response between the proband and her mother. Future study will decipher by which molecular mechanisms the nuclear background influences the penetrance of the m.1630 A > G variant causing MELAS.
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Affiliation(s)
- Martine Uittenbogaard
- Department of Anatomy and Cell Biology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Hao Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Victor Wei Zhang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; AmCare Genomics Laboratory, GuangZhou 510300, China
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Christine A Brantner
- GW Nanofabrication and Imaging Center, Office of the Vice President for Research, George Washington University, Washington, DC 20052, USA
| | - Andrea Gropman
- Children's National Medical Center, Division of Neurogenetics and Developmental Pediatrics, Washington, DC 20010, USA
| | - Anne Chiaramello
- Department of Anatomy and Cell Biology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA.
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13
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Tranah GJ, Maglione JE, Yaffe K, Katzman SM, Manini TM, Kritchevsky S, Newman AB, Harris TB, Cummings SR. Mitochondrial DNA m.13514G>A heteroplasmy is associated with depressive symptoms in the elderly. Int J Geriatr Psychiatry 2018; 33:1319-1326. [PMID: 29984425 DOI: 10.1002/gps.4928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 05/14/2018] [Indexed: 12/17/2022]
Abstract
OBJECTIVES Mitochondrial DNA (mtDNA) heteroplasmy is a mixture of normal and mutated mtDNA molecules in a cell. High levels of heteroplasmy at several mtDNA sites in complex I lead to inherited neurological neurologic diseases and brain magnetic resonance imaging (MRI) abnormalities. Here, we test the hypothesis that mtDNA heteroplasmy at these complex I sites is associated with depressive symptoms in the elderly. METHODS We examined platelet mtDNA heteroplasmy for associations with depressive symptoms among 137 participants over age 70 from the community-based Health, Aging and Body Composition Study. Depressive symptoms were assessed using the 10-point version of the Center for Epidemiologic Studies Depression Scale (CES-D 10). Complete mtDNA sequencing was performed and heteroplasmy derived for 5 mtDNA sites associated with neurologic mitochondrial diseases and tested for associations with depressive symptoms. RESULTS Of 5 candidate complex I mtDNA mutations examined for effects on depressive symptoms, increased heteroplasmy at m.13514A>G, ND5, was significantly associated with higher CES-D score (P = .01). A statistically significant interaction between m.13514A > G heteroplasmy and sex was detected (P = .04); in sex-stratified analyses, the impact of m.13514A>G heteroplasmy was stronger in male (P = .003) than in female (P = .98) participants. Men in highest tertile of mtDNA heteroplasmy exhibited significantly higher (P = .0001) mean ± SE CES-D 10 scores, 5.37 ± 0.58, when compared with those in the middle, 2.13 ± 0.52, and lowest tertiles, 2.47 ± 0.58. No associations between the 4 other candidate sites and depressive symptoms were observed. CONCLUSIONS Increased mtDNA heteroplasmy at m.13514A>G is associated with depressive symptoms in older men. Heteroplasmy may represent a novel biological risk factor for depression.
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Affiliation(s)
- Gregory J Tranah
- California Pacific Medical Center Research Institute, San Francisco, San Francisco, CA, USA
| | - Jeanne E Maglione
- University of California, San Diego, Department of Psychiatry, La Jolla, CA, USA
| | - Kristine Yaffe
- University of California, San Francisco, Departments of Psychiatry, Neurology, and Epidemiology, San Francisco, CA, USA.,San Francisco VA Medical Center, San Francisco, CA, USA
| | | | - Todd M Manini
- University of Florida, Department of Aging and Geriatric Research, Gainesville, FL, USA
| | - Stephen Kritchevsky
- Wake Forest School of Medicine, Sticht Center on Aging, Winston-Salem, NC, USA
| | - Anne B Newman
- University of Pittsburgh, Department of Epidemiology, Pittsburgh, PA, USA
| | - Tamara B Harris
- National Institute on Aging, Intramural Research Program, Laboratory of Epidemiology and Population Sciences, Bethesda, MD, USA
| | - Steven R Cummings
- California Pacific Medical Center Research Institute, San Francisco, San Francisco, CA, USA
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14
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Tranah GJ, Katzman SM, Lauterjung K, Yaffe K, Manini TM, Kritchevsky S, Newman AB, Harris TB, Cummings SR. Mitochondrial DNA m.3243A > G heteroplasmy affects multiple aging phenotypes and risk of mortality. Sci Rep 2018; 8:11887. [PMID: 30089816 PMCID: PMC6082898 DOI: 10.1038/s41598-018-30255-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 07/20/2018] [Indexed: 12/13/2022] Open
Abstract
Mitochondria contain many copies of a circular DNA molecule (mtDNA), which has been observed as a mixture of normal and mutated states known as heteroplasmy. Elevated heteroplasmy at a single mtDNA site, m.3243A > G, leads to neurologic, sensory, movement, metabolic, and cardiopulmonary impairments. We measured leukocyte mtDNA m.3243A > G heteroplasmy in 789 elderly men and women from the bi-racial, population-based Health, Aging, and Body Composition Study to identify associations with age-related functioning and mortality. Mutation burden for the m.3243A > G ranged from 0-19% and elevated heteroplasmy was associated with reduced strength, cognitive, metabolic, and cardiovascular functioning. Risk of all-cause, dementia and stroke mortality was significantly elevated for participants in the highest tertiles of m.3243A > G heteroplasmy. These results indicate that the accumulation of a rare genetic disease mutation, m.3243A > G, manifests as several aging outcomes and that some diseases of aging may be attributed to the accumulation of mtDNA damage.
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Grants
- R01-NR012459 U.S. Department of Health & Human Services | National Institutes of Health (NIH)
- R01 HL121023 NHLBI NIH HHS
- N01-AG-6-2106 U.S. Department of Health & Human Services | NIH | National Institute on Aging (U.S. National Institute on Aging)
- R01-HL121023 U.S. Department of Health & Human Services | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- P30 AG028740 NIA NIH HHS
- Z01A6000932 Office of Extramural Research, National Institutes of Health (OER)
- R03-AG032498 U.S. Department of Health & Human Services | NIH | National Institute on Aging (U.S. National Institute on Aging)
- R01-AG028050 U.S. Department of Health & Human Services | NIH | National Institute on Aging (U.S. National Institute on Aging)
- R01 NR012459 NINR NIH HHS
- R03 AG032498 NIA NIH HHS
- R01 AG028050 NIA NIH HHS
- This research was supported in part by the Intramural Research Program of the NIH, National Institute on Aging, Contracts N01-AG-6-2101, N01-AG-6-2103, and N01-AG-6-2106; National Institutes of Health grants R01-AG028050, R03-AG032498, R01-NR012459, Z01A6000932, R01-HL121023, and a grant from the Research and Education Leadership Committee of the CPMC Foundation and the L. K. Whittier Foundation.
- U.S. Department of Health & Human Services | NIH | National Institute on Aging (U.S. National Institute on Aging)
- U.S. Department of Health & Human Services | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- U.S. Department of Health & Human Services | National Institutes of Health (NIH)
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Affiliation(s)
- Gregory J Tranah
- California Pacific Medical Center Research Institute, San Francisco, CA, 94107, USA.
| | | | - Kevin Lauterjung
- California Pacific Medical Center Research Institute, San Francisco, CA, 94107, USA
| | - Kristine Yaffe
- Departments of Psychiatry, Neurology, and Epidemiology, University of California, San Francisco and the San Francisco VA Medical Center, San Francisco, CA, 94121, USA
| | - Todd M Manini
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, 32601, USA
| | - Stephen Kritchevsky
- Sticht Center on Aging, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - Anne B Newman
- Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Tamara B Harris
- Intramural Research Program, Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, MD, 20892, USA
| | - Steven R Cummings
- California Pacific Medical Center Research Institute, San Francisco, CA, 94107, USA
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15
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Zhao X, Han J, Zhu L, Xiao Y, Wang C, Hong F, Jiang P, Guan MX. Overexpression of human mitochondrial alanyl-tRNA synthetase suppresses biochemical defects of the mt-tRNA Ala mutation in cybrids. Int J Biol Sci 2018; 14:1437-1444. [PMID: 30262995 PMCID: PMC6158735 DOI: 10.7150/ijbs.27043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/17/2018] [Indexed: 11/13/2022] Open
Abstract
Mutations of mitochondrial transfer RNAs (mt-tRNAs) play a major role in a wide range of mitochondrial diseases because of the vital role of these molecules in mitochondrial translation. It has previously been reported that the overexpression of mitochondrial aminoacyl tRNA synthetases is effective at partially suppressing the defects resulting from mutations in their cognate mt-tRNAs in cells. Here we report a detailed analysis of the suppressive activities of mitochondrial alanyl-tRNA synthetase (AARS2) on mt-tRNAAla 5655 A>G mutant. Mitochondrial defects in respiration, activity of oxidative phosphorylation complexes, ATP production, mitochondrial superoxide, and membrane potential were consistently rescued in m.5655A>G cybrids upon AARS2 expression. However, AARS2 overexpression did not result in a detectable increase in mutated mt-tRNAAla but caused an increase incharged mt-tRNAAla in mutant cybrids, leading to enhanced mitochondrial translation. This indicated that AARS2 improved the aminoacylation activity in the case of m.5655A>G, rather than having a stabilizing effect on the tRNA structure. The data presented in this paper deepen our understanding of the pathogenesis of mt-tRNA diseases.
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Affiliation(s)
- Xiaoxu Zhao
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.,Institute of Genetics Zhejiang University, and Department of Human Genetics, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jiamin Han
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.,Institute of Genetics Zhejiang University, and Department of Human Genetics, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Ling Zhu
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Yun Xiao
- Institute of Genetics Zhejiang University, and Department of Human Genetics, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Chenghui Wang
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.,Institute of Genetics Zhejiang University, and Department of Human Genetics, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Fang Hong
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Pingping Jiang
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.,Institute of Genetics Zhejiang University, and Department of Human Genetics, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Min-Xin Guan
- Division of Medical Genetics and Genomics, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.,Institute of Genetics Zhejiang University, and Department of Human Genetics, Zhejiang University School of Medicine, Hangzhou, 310058, China
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16
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Emerging therapies for mitochondrial diseases. Essays Biochem 2018; 62:467-481. [PMID: 29980632 DOI: 10.1042/ebc20170114] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 05/20/2018] [Accepted: 05/23/2018] [Indexed: 12/25/2022]
Abstract
For the vast majority of patients with mitochondrial diseases, only supportive and symptomatic therapies are available. However, in the last decade, due to extraordinary advances in defining the causes and pathomechanisms of these diverse disorders, new therapies are being developed in the laboratory and are entering human clinical trials. In this review, we highlight the current use of dietary supplement and exercise therapies as well as emerging therapies that may be broadly applicable across multiple mitochondrial diseases or tailored for specific disorders. Examples of non-tailored therapeutic targets include: activation of mitochondrial biogenesis, regulation of mitophagy and mitochondrial dynamics, bypass of biochemical defects, mitochondrial replacement therapy, and hypoxia. In contrast, tailored therapies are: scavenging of toxic compounds, deoxynucleoside and deoxynucleotide treatments, cell replacement therapies, gene therapy, shifting mitochondrial DNA mutation heteroplasmy, and stabilization of mutant mitochondrial transfer RNAs.
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17
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Yuan FF, Ye XP, Liu W, Xue LQ, Ma YR, Zhang LL, Zhang MM, Sun F, Wan YY, Zhang QY, Zhao SX, Song HD. Genetic study of early-onset Graves' disease in the Chinese Han population. Clin Genet 2017; 93:103-110. [PMID: 28598035 DOI: 10.1111/cge.13072] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 05/31/2017] [Indexed: 01/19/2023]
Abstract
Graves' disease (GD) is a complex autoimmune disorder in which genetic and environmental factors are both involved in the pathogenesis. Early-onset patients have a shorter exposure time to environmental factors and are, therefore, good models to help understand the genetic architecture of GD. Based on previous studies of early-onset GD, 11 single nucleotide polymorphisms (SNPs) and their related SNPs (R2 > .6), SNPs located within a ±1-Mb region of the FOXP3 gene, and 20 validated GD-risk SNPs were selected and screened for genotyping in 3735 GD and 4893 control patients to investigate whether early-onset GD is a subtype of GD with distinct susceptibility genes. Ultimately, we did not confirm the reported genetic markers of early-onset GD in our Chinese Han population but found that a GD-risk SNP located in the human leukocyte antigen class I region-rs4947296-was more strongly correlated with early-onset GD than non-early-onset GD. In addition, heterogeneity analysis of GD patients suggests that it may be more reasonable to define early-onset GD as an onset age ≤20 years.
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Affiliation(s)
- F-F Yuan
- The Core Laboratory in Medicine Center of Clinical Research, Department of Endocrinology, The Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China.,Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China
| | - X-P Ye
- The Core Laboratory in Medicine Center of Clinical Research, Department of Endocrinology, The Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - W Liu
- The Core Laboratory in Medicine Center of Clinical Research, Department of Endocrinology, The Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China.,Department of Endocrinology, The Ninth People's Hospital (the north branch) Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - L-Q Xue
- The Core Laboratory in Medicine Center of Clinical Research, Department of Endocrinology, The Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Y-R Ma
- The Core Laboratory in Medicine Center of Clinical Research, Department of Endocrinology, The Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - L-L Zhang
- The Core Laboratory in Medicine Center of Clinical Research, Department of Endocrinology, The Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - M-M Zhang
- The Core Laboratory in Medicine Center of Clinical Research, Department of Endocrinology, The Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - F Sun
- The Core Laboratory in Medicine Center of Clinical Research, Department of Endocrinology, The Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Y-Y Wan
- The Core Laboratory in Medicine Center of Clinical Research, Department of Endocrinology, The Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Q-Y Zhang
- The Core Laboratory in Medicine Center of Clinical Research, Department of Endocrinology, The Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - S-X Zhao
- The Core Laboratory in Medicine Center of Clinical Research, Department of Endocrinology, The Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - H-D Song
- The Core Laboratory in Medicine Center of Clinical Research, Department of Endocrinology, The Ninth People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China
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18
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Chrzanowska-Lightowlers Z, Rorbach J, Minczuk M. Human mitochondrial ribosomes can switch structural tRNAs - but when and why? RNA Biol 2017; 14:1668-1671. [PMID: 28786741 PMCID: PMC5731804 DOI: 10.1080/15476286.2017.1356551] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
High resolution cryoEM of mammalian mitoribosomes revealed the unexpected presence of mitochondrially encoded tRNA as a structural component of mitochondrial large ribosomal subunit (mt-LSU). Our previously published data identified that only mitochondrial (mt-) tRNAPhe and mt-tRNAVal can be incorporated into mammalian mt-LSU and within an organism there is no evidence of tissue specific variation. When mt-tRNAVal is limiting, human mitoribosomes can integrate mt-tRNAPhe instead to generate a translationally competent monosome. Here we discuss the possible reasons for and consequences of the observed plasticity of the structural mt-tRNA integration. We also indicate potential direction for further research that could help our understanding of the mechanistic and evolutionary aspects of this unprecedented system.
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Affiliation(s)
- Zofia Chrzanowska-Lightowlers
- a The Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience , Newcastle University , Newcastle upon Tyne , England , UK
| | - Joanna Rorbach
- b Department of Medical Biochemistry and Biophysics , Karolinska Institutet , Retzius väg 8, Stockholm , Sweden
| | - Michal Minczuk
- c MRC Mitochondrial Biology Unit , Wellcome Trust/MRC Building, Hills Road, Cambridge, England , UK
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19
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Morrow EH, Camus MF. Mitonuclear epistasis and mitochondrial disease. Mitochondrion 2017; 35:119-122. [PMID: 28603048 DOI: 10.1016/j.mito.2017.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 06/06/2017] [Accepted: 06/06/2017] [Indexed: 12/01/2022]
Affiliation(s)
- Edward H Morrow
- School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom.
| | - M Florencia Camus
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
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20
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de Taffin de Tilques M, Tribouillard-Tanvier D, Tétaud E, Testet E, di Rago JP, Lasserre JP. Overexpression of mitochondrial oxodicarboxylate carrier (ODC1) preserves oxidative phosphorylation in a yeast model of Barth syndrome. Dis Model Mech 2017; 10:439-450. [PMID: 28188263 PMCID: PMC5399564 DOI: 10.1242/dmm.027540] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 02/04/2017] [Indexed: 12/21/2022] Open
Abstract
Cardiolipin (CL) is a diglycerol phospholipid mostly found in mitochondria where it optimizes numerous processes, including oxidative phosphorylation (OXPHOS). To function properly, CL needs to be unsaturated, which requires the acyltransferase tafazzin. Loss-of-function mutations in this protein are responsible for Barth syndrome (BTHS), presumably because of a diminished OXPHOS capacity. Here, we show that overexpressing Odc1p, a conserved oxodicarboxylic acid carrier located in the mitochondrial inner membrane, fully restores oxidative phosphorylation in a yeast model (taz1Δ) of BTHS. The rescuing activity involves the recovery of normal expression of key components that sustain oxidative phosphorylation, including cytochrome c and electron transport chain complexes IV and III, which are strongly downregulated in taz1Δ yeast. Interestingly, overexpression of Odc1p was also shown previously to rescue yeast models of mitochondrial diseases caused by defects in the assembly of ATP synthase and by mutations in the MPV17 protein that result in hepatocerebral mitochondrial DNA depletion syndrome. These findings define the transport of oxodicarboxylic acids across the inner membrane as a potential therapeutic target for a large spectrum of mitochondrial diseases, including BTHS.
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Affiliation(s)
- Maxence de Taffin de Tilques
- Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires, CNRS UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux cedex 33077, France
| | - Déborah Tribouillard-Tanvier
- Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires, CNRS UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux cedex 33077, France
| | - Emmanuel Tétaud
- Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires, CNRS UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux cedex 33077, France
| | - Eric Testet
- Université de Bordeaux, Laboratoire de biogenèse membranaire, CNRS UMR 5200, INRA Bordeaux Aquitaine BP81, 33883 Villenave d'Ornon Cédex, France
| | - Jean-Paul di Rago
- Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires, CNRS UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux cedex 33077, France
| | - Jean-Paul Lasserre
- Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires, CNRS UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux cedex 33077, France
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21
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Francisci S, Montanari A. Mitochondrial diseases: Yeast as a model for the study of suppressors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:666-673. [PMID: 28089773 DOI: 10.1016/j.bbamcr.2017.01.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 12/22/2016] [Accepted: 01/11/2017] [Indexed: 11/27/2022]
Abstract
Mitochondrial (mt) tRNA gene mutations are an important cause of human morbidity and are associated with different syndromes. We have previously shown that the mitochondrial protein synthesis elongation factor EF-Tu and isolated sequences from the carboxy-terminal domain of yeast and human mt leucyl-tRNA synthetases (LeuRS), have a wide range of suppression capability among different yeast mt tRNA mutants having defective respiratory phenotype. Here we show that the rescuing capability can be restricted to a specific sequence of six amino acids from the carboxy-terminal domain of mt LeuRS. On the other hand by overexpressing a mutated version of mt EF-Tu in a yeast strain deleted for the endogenous nuclear gene we identified the specific region involved in suppression. Results support the possibility that a small peptide could correct defects associated with many mt tRNA mutations, suggesting a novel therapy for mitochondrial diseases treatment. The involvement of the mt EF-Tu in cellular heat stress response has also been suggested.
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Affiliation(s)
- Silvia Francisci
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy.
| | - Arianna Montanari
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy; Pasteur Institute Italy - Cenci Bolognetti Foundation, Sapienza University of Rome, Viale Regina Elena, 291, 00161 Rome, Italy.
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22
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Human mitochondrial ribosomes can switch their structural RNA composition. Proc Natl Acad Sci U S A 2016; 113:12198-12201. [PMID: 27729525 DOI: 10.1073/pnas.1609338113] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The recent developments in cryo-EM have revolutionized our access to previously refractory structures. In particular, such studies of mammalian mitoribosomes have confirmed the absence of any 5S rRNA species and revealed the unexpected presence of a mitochondrially encoded tRNA (mt-tRNA) that usurps this position. Although the cryo-EM structures resolved the conundrum of whether mammalian mitoribosomes contain a 5S rRNA, they introduced a new dilemma: Why do human and porcine mitoribosomes integrate contrasting mt-tRNAs? Human mitoribosomes have been shown to integrate mt-tRNAVal compared with the porcine use of mt-tRNAPhe We have explored this observation further. Our studies examine whether a range of mt-tRNAs are used by different mammals, or whether the mt-tRNA selection is strictly limited to only these two species of the 22 tRNAs encoded by the mitochondrial genome (mtDNA); whether there is tissue-specific variation within a single organism; and what happens to the human mitoribosome when levels of the mt-tRNAVal are depleted. Our data demonstrate that only mt-tRNAVal or mt-tRNAPhe are found in the mitoribosomes of five different mammals, each mammal favors the same mt-tRNA in all tissue types, and strikingly, when steady-state levels of mt-tRNAVal are reduced, human mitoribosome biogenesis displays an adaptive response by switching to the incorporation of mt-tRNAPhe to generate translationally competent machinery.
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23
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López-Gallardo E, Llobet L, Emperador S, Montoya J, Ruiz-Pesini E. Effects of Tributyltin Chloride on Cybrids with or without an ATP Synthase Pathologic Mutation. ENVIRONMENTAL HEALTH PERSPECTIVES 2016; 124:1399-405. [PMID: 27129022 PMCID: PMC5010394 DOI: 10.1289/ehp182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/27/2015] [Accepted: 04/13/2016] [Indexed: 05/05/2023]
Abstract
BACKGROUND The oxidative phosphorylation system (OXPHOS) includes nuclear chromosome (nDNA)- and mitochondrial DNA (mtDNA)-encoded polypeptides. Many rare OXPHOS disorders, such as striatal necrosis syndromes, are caused by genetic mutations. Despite important advances in sequencing procedures, causative mutations remain undetected in some patients. It is possible that etiologic factors, such as environmental toxins, are the cause of these cases. Indeed, the inhibition of a particular enzyme by a poison could imitate the biochemical effects of pathological mutations in that enzyme. Moreover, environmental factors can modify the penetrance or expressivity of pathological mutations. OBJECTIVES We studied the interaction between mitochondrially encoded ATP synthase 6 (p.MT-ATP6) subunit and an environmental exposure that may contribute phenotypic differences between healthy individuals and patients suffering from striatal necrosis syndromes or other mitochondriopathies. METHODS We analyzed the effects of the ATP synthase inhibitor tributyltin chloride (TBTC), a widely distributed environmental factor that contaminates human food and water, on transmitochondrial cell lines with or without an ATP synthase mutation that causes striatal necrosis syndrome. Doses were selected based on TBTC concentrations previously reported in human whole blood samples. RESULTS TBTC modified the phenotypic effects caused by a pathological mtDNA mutation. Interestingly, wild-type cells treated with this xenobiotic showed similar bioenergetics when compared with the untreated mutated cells. CONCLUSIONS In addition to the known genetic causes, our findings suggest that environmental exposure to TBTC might contribute to the etiology of striatal necrosis syndromes. CITATION López-Gallardo E, Llobet L, Emperador S, Montoya J, Ruiz-Pesini E. 2016. Effects of tributyltin chloride on cybrids with or without an ATP synthase pathologic mutation. Environ Health Perspect 124:1399-1405; http://dx.doi.org/10.1289/EHP182.
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Affiliation(s)
- Ester López-Gallardo
- Departamento de Bioquímica, Biología Molecular y Celular,
- Instituto de Investigación Sanitaria de Aragón,
- CIBER de Enfermedades Raras (CIBERER), and
| | - Laura Llobet
- Departamento de Bioquímica, Biología Molecular y Celular,
- Instituto de Investigación Sanitaria de Aragón,
- CIBER de Enfermedades Raras (CIBERER), and
| | - Sonia Emperador
- Departamento de Bioquímica, Biología Molecular y Celular,
- Instituto de Investigación Sanitaria de Aragón,
- CIBER de Enfermedades Raras (CIBERER), and
| | - Julio Montoya
- Departamento de Bioquímica, Biología Molecular y Celular,
- Instituto de Investigación Sanitaria de Aragón,
- CIBER de Enfermedades Raras (CIBERER), and
- Address correspondence to E. Ruiz-Pesini, Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza. C/ Miguel Servet, 177. 50013-Zaragoza, Spain. Telephone: 34-976761640. E-mail: , or J. Montoya, Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza. C/ Miguel Servet, 177. 50013-Zaragoza, Spain. Telephone: 34-976761640. E-mail:
| | - Eduardo Ruiz-Pesini
- Departamento de Bioquímica, Biología Molecular y Celular,
- Instituto de Investigación Sanitaria de Aragón,
- CIBER de Enfermedades Raras (CIBERER), and
- Fundación ARAID, Universidad de Zaragoza, Zaragoza, Spain
- Address correspondence to E. Ruiz-Pesini, Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza. C/ Miguel Servet, 177. 50013-Zaragoza, Spain. Telephone: 34-976761640. E-mail: , or J. Montoya, Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza. C/ Miguel Servet, 177. 50013-Zaragoza, Spain. Telephone: 34-976761640. E-mail:
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24
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Darbandi S, Darbandi M, Khorshid HRK, Sadeghi MR, Al-Hasani S, Agarwal A, Shirazi A, Heidari M, Akhondi MM. Experimental strategies towards increasing intracellular mitochondrial activity in oocytes: A systematic review. Mitochondrion 2016; 30:8-17. [PMID: 27234976 DOI: 10.1016/j.mito.2016.05.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 04/04/2016] [Accepted: 05/20/2016] [Indexed: 12/19/2022]
Abstract
PURPOSE The mitochondrial complement is critical in sustaining the earliest stages of life. To improve the Assisted Reproductive Technology (ART), current methods of interest were evaluated for increasing the activity and copy number of mitochondria in the oocyte cell. METHODS This covered the researches from 1966 to September 2015. RESULTS The results provided ten methods that can be studied individually or simultaneously. CONCLUSION Though the use of these techniques generated great concern about heteroplasmy observation in humans, it seems that with study on these suggested methods there is real hope for effective treatments of old oocyte or oocytes containing mitochondrial problems in the near future.
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Affiliation(s)
- Sara Darbandi
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.
| | - Mahsa Darbandi
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.
| | | | - Mohammad Reza Sadeghi
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.
| | - Safaa Al-Hasani
- Reproductive Medicine Unit, University of Schleswig-Holstein, Luebeck, Germany.
| | - Ashok Agarwal
- Center for Reproductive Medicine, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, OH, USA.
| | - Abolfazl Shirazi
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.
| | - Mahnaz Heidari
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran. M.@avicenna.ar.ir
| | - Mohammad Mehdi Akhondi
- Reproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran.
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25
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Nightingale H, Pfeffer G, Bargiela D, Horvath R, Chinnery PF. Emerging therapies for mitochondrial disorders. Brain 2016; 139:1633-48. [PMID: 27190030 PMCID: PMC4892756 DOI: 10.1093/brain/aww081] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/26/2016] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial disorders are a diverse group of debilitating conditions resulting from nuclear and mitochondrial DNA mutations that affect multiple organs, often including the central and peripheral nervous system. Despite major advances in our understanding of the molecular mechanisms, effective treatments have not been forthcoming. For over five decades patients have been treated with different vitamins, co-factors and nutritional supplements, but with no proven benefit. There is therefore a clear need for a new approach. Several new strategies have been proposed acting at the molecular or cellular level. Whilst many show promise in vitro, the clinical potential of some is questionable. Here we critically appraise the most promising preclinical developments, placing the greatest emphasis on diseases caused by mitochondrial DNA mutations. With new animal and cellular models, longitudinal deep phenotyping in large patient cohorts, and growing interest from the pharmaceutical industry, the field is poised to make a breakthrough.
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Affiliation(s)
- Helen Nightingale
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Gerald Pfeffer
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK Department of Clinical Neurosciences, University of Calgary, Calgary, Canada Hotchkiss Brain Institute, at the University of Calgary, Calgary, Canada
| | - David Bargiela
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Rita Horvath
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Patrick F Chinnery
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK MRC-Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, CB2 0QQ, UK
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26
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Perli E, Fiorillo A, Giordano C, Pisano A, Montanari A, Grazioli P, Campese AF, Di Micco P, Tuppen HA, Genovese I, Poser E, Preziuso C, Taylor RW, Morea V, Colotti G, d'Amati G. Short peptides from leucyl-tRNA synthetase rescue disease-causing mitochondrial tRNA point mutations. Hum Mol Genet 2016; 25:903-15. [PMID: 26721932 PMCID: PMC4754043 DOI: 10.1093/hmg/ddv619] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 12/18/2015] [Indexed: 01/11/2023] Open
Abstract
Mutations in mitochondrial (mt) genes coding for mt-tRNAs are responsible for a range of syndromes, for which no effective treatment is available. We recently showed that the carboxy-terminal domain (Cterm) of human mt-leucyl tRNA synthetase rescues the pathologic phenotype associated either with the m.3243A>G mutation in mt-tRNA(Leu(UUR)) or with mutations in the mt-tRNA(Ile), both of which are aminoacylated by Class I mt-aminoacyl-tRNA synthetases (mt-aaRSs). Here we show, by using the human transmitochondrial cybrid model, that the Cterm is also able to improve the phenotype caused by the m.8344A>G mutation in mt-tRNA(Lys), aminoacylated by a Class II aaRS. Importantly, we demonstrate that the same rescuing ability is retained by two Cterm-derived short peptides, β30_31 and β32_33, which are effective towards both the m.8344A>G and the m.3243A>G mutations. Furthermore, we provide in vitro evidence that these peptides bind with high affinity wild-type and mutant human mt-tRNA(Leu(UUR)) and mt-tRNA(Lys), and stabilize mutant mt-tRNA(Leu(UUR)). In conclusion, we demonstrate that small Cterm-derived peptides can be effective tools to rescue cellular defects caused by mutations in a wide range of mt-tRNAs.
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Affiliation(s)
- Elena Perli
- Department of Radiology, Oncology and Pathology
| | | | | | | | - Arianna Montanari
- Department of Biology and Biotechnologies 'Charles Darwin' and Pasteur Institute-Cenci Bolognetti Foundation, Rome 00161, Italy
| | - Paola Grazioli
- Department of Molecular Medicine, Sapienza University of Rome, Rome 00161, Italy
| | - Antonio F Campese
- Department of Molecular Medicine, Sapienza University of Rome, Rome 00161, Italy
| | | | - Helen A Tuppen
- Wellcome Trust Center for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE1 7RU, UK and
| | | | - Elena Poser
- Department of Biochemical Sciences "A. Rossi Fanelli"
| | | | - Robert W Taylor
- Wellcome Trust Center for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE1 7RU, UK and
| | - Veronica Morea
- National Research Council of Italy, Institute of Molecular Biology and Pathology, Rome 00185, Italy
| | - Gianni Colotti
- National Research Council of Italy, Institute of Molecular Biology and Pathology, Rome 00185, Italy
| | - Giulia d'Amati
- Department of Radiology, Oncology and Pathology, Pasteur Institute-Cenci Bolognetti Foundation, Rome 00161, Italy,
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27
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Lasserre JP, Dautant A, Aiyar RS, Kucharczyk R, Glatigny A, Tribouillard-Tanvier D, Rytka J, Blondel M, Skoczen N, Reynier P, Pitayu L, Rötig A, Delahodde A, Steinmetz LM, Dujardin G, Procaccio V, di Rago JP. Yeast as a system for modeling mitochondrial disease mechanisms and discovering therapies. Dis Model Mech 2016; 8:509-26. [PMID: 26035862 PMCID: PMC4457039 DOI: 10.1242/dmm.020438] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mitochondrial diseases are severe and largely untreatable. Owing to the many essential processes carried out by mitochondria and the complex cellular systems that support these processes, these diseases are diverse, pleiotropic, and challenging to study. Much of our current understanding of mitochondrial function and dysfunction comes from studies in the baker's yeast Saccharomyces cerevisiae. Because of its good fermenting capacity, S. cerevisiae can survive mutations that inactivate oxidative phosphorylation, has the ability to tolerate the complete loss of mitochondrial DNA (a property referred to as ‘petite-positivity’), and is amenable to mitochondrial and nuclear genome manipulation. These attributes make it an excellent model system for studying and resolving the molecular basis of numerous mitochondrial diseases. Here, we review the invaluable insights this model organism has yielded about diseases caused by mitochondrial dysfunction, which ranges from primary defects in oxidative phosphorylation to metabolic disorders, as well as dysfunctions in maintaining the genome or in the dynamics of mitochondria. Owing to the high level of functional conservation between yeast and human mitochondrial genes, several yeast species have been instrumental in revealing the molecular mechanisms of pathogenic human mitochondrial gene mutations. Importantly, such insights have pointed to potential therapeutic targets, as have genetic and chemical screens using yeast. Summary: In this Review, we discuss the use of budding yeast to understand mitochondrial diseases and help in the search for their treatments.
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Affiliation(s)
- Jean-Paul Lasserre
- University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux F-33000, France
| | - Alain Dautant
- University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux F-33000, France
| | - Raeka S Aiyar
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Roza Kucharczyk
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Annie Glatigny
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, 1 avenue de la terrasse, Gif-sur-Yvette 91198, France
| | - Déborah Tribouillard-Tanvier
- Institut National de la Santé et de la Recherche Médicale UMR1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest F-29200, France
| | - Joanna Rytka
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Marc Blondel
- Institut National de la Santé et de la Recherche Médicale UMR1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest F-29200, France
| | - Natalia Skoczen
- University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux F-33000, France Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Pascal Reynier
- UMR CNRS 6214-INSERM U1083, Angers 49933, Cedex 9, France Département de Biochimie et Génétique, Centre Hospitalier Universitaire d'Angers, Angers 49933, Cedex 9, France
| | - Laras Pitayu
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, rue Gregor Mendel, Orsay 91405, France
| | - Agnès Rötig
- Inserm U1163, Hôpital Necker-Enfants-Malades, Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, 149 rue de Sèvres, Paris 75015, France
| | - Agnès Delahodde
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, rue Gregor Mendel, Orsay 91405, France
| | - Lars M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany Stanford Genome Technology Center, Department of Biochemistry, Stanford University, Palo Alto, CA 94304, USA Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5301, USA
| | - Geneviève Dujardin
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, 1 avenue de la terrasse, Gif-sur-Yvette 91198, France
| | - Vincent Procaccio
- UMR CNRS 6214-INSERM U1083, Angers 49933, Cedex 9, France Département de Biochimie et Génétique, Centre Hospitalier Universitaire d'Angers, Angers 49933, Cedex 9, France
| | - Jean-Paul di Rago
- University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux F-33000, France
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28
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Tranah GJ, Yaffe K, Katzman SM, Lam ET, Pawlikowska L, Kwok PY, Schork NJ, Manini TM, Kritchevsky S, Thomas F, Newman AB, Harris TB, Coleman AL, Gorin MB, Helzner EP, Rowbotham MC, Browner WS, Cummings SR. Mitochondrial DNA Heteroplasmy Associations With Neurosensory and Mobility Function in Elderly Adults. J Gerontol A Biol Sci Med Sci 2015; 70:1418-24. [PMID: 26328603 DOI: 10.1093/gerona/glv097] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/05/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Mitochondrial DNA (mtDNA) heteroplasmy is a mixture of normal and mutated mtDNA molecules in a cell. High levels of heteroplasmy at specific mtDNA sites lead to inherited mitochondrial diseases with neurological, sensory, and movement impairments. Here we test the hypothesis that heteroplasmy levels in elderly adults are associated with impaired function resembling mild forms of mitochondrial disease. METHODS We examined platelet mtDNA heteroplasmy at 20 disease-causing sites for associations with neurosensory and mobility function among 137 participants from the community-based Health, Aging, and Body Composition Study. RESULTS Elevated mtDNA heteroplasmy at four mtDNA sites in complex I and tRNA genes was nominally associated with reduced cognition, vision, hearing, and mobility: m.10158T>C with Modified Mini-Mental State Examination score (p = .009); m.11778G>A with contrast sensitivity (p = .02); m.7445A>G with high-frequency hearing (p = .047); and m.5703G>A with 400 m walking speed (p = .007). CONCLUSIONS These results indicate that increased mtDNA heteroplasmy at disease-causing sites is associated with neurosensory and mobility function in older persons. We propose the novel use of mtDNA heteroplasmy as a simple, noninvasive predictor of age-related neurologic, sensory, and movement impairments.
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Affiliation(s)
- Gregory J Tranah
- California Pacific Medical Center Research Institute, San Francisco.
| | - Kristine Yaffe
- Department of Psychiatry, Department of Neurology and Department of Epidemiology, University of California San Francisco and the San Francisco VA Medical Center
| | | | | | - Ludmila Pawlikowska
- Department of Anesthesia and Perioperative Care, University of California San Francisco. Institute for Human Genetics, University of California San Francisco
| | - Pui-Yan Kwok
- Institute for Human Genetics, University of California San Francisco
| | - Nicholas J Schork
- J. Craig Venter Institute and the University of California, San Diego
| | - Todd M Manini
- Department of Aging and Geriatric Research, University of Florida, Gainesville
| | - Stephen Kritchevsky
- Sticht Center on Aging, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Fridtjof Thomas
- Department of Preventive Medicine, The University of Tennessee Health Science Center, Memphis
| | - Anne B Newman
- Department of Epidemiology, University of Pittsburgh, Pennsylvania
| | - Tamara B Harris
- Intramural Research Program, Laboratory of Epidemiology and Population Sciences, National Institute on Aging, Bethesda, Maryland
| | - Anne L Coleman
- Jules Stein Eye Institute and UCLA Department of Ophthalmology, Los Angeles, California
| | - Michael B Gorin
- Jules Stein Eye Institute and UCLA Department of Ophthalmology, Los Angeles, California
| | - Elizabeth P Helzner
- Department of Epidemiology and Biostatistics, SUNY Downstate Medical Center, Brooklyn, New York
| | | | - Warren S Browner
- California Pacific Medical Center Research Institute, San Francisco
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29
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Cheong HS, Lee JH, Yu SJ, Yoon JH, Lee HS, Cheong JY, Cho SW, Park NH, Park BL, Namgoong S, Kim LH, Shin HD, Kim YJ. Association of VARS2-SFTA2 polymorphisms with the risk of chronic hepatitis B in a Korean population. Liver Int 2015; 35:1934-40. [PMID: 25404243 DOI: 10.1111/liv.12740] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 11/13/2014] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Hepatitis B virus (HBV) infection is the most serious risk factor for chronic hepatitis B (CHB), cirrhosis, and hepatocellular carcinoma. Recently, several genome-wide association studies (GWASs) identified important variants associated with the risk of CHB in Asian populations. Specifically, our previous GWAS identified the VARS2-SFTA2 gene region as one of the genetic risk loci for CHB. METHODS To further characterize this association and to isolate possible causal variants within it, we performed an additional association study by genotyping more SNPs in the vicinity of the VARS2 and SFTA2 genes. In all, 14 SNPs of VARS2-SFTA2 were analysed among a total of 3902 subjects (1046 cases and 2856 controls). RESULTS Logistic regression analysis revealed that six SNPs, including the previously reported rs2532932, were significantly associated with the risk of CHB (P = 1.7 × 10(-10) ~0.002). Further linkage disequilibrium and conditional analysis identified two variants (rs9394021 and rs2517459) as new markers of genetic risk factors for CHB rather than the reported SNP from our previous study (rs2532932). To evaluate the cumulative risk for CHB based on all known genetic factors, genetic risk score (GRS) were calculated. As anticipated, the distribution of the number of risk alleles in cases vs. controls clearly differed according to the GRS. Similarly, the odds ratios (ORs) were increased (OR = 0.32-3.97). CONCLUSION Our findings show that common variants in the VARS2-SFTA2 gene region are significantly associated with CHB in a Korean population, which may be useful in further understanding genetic susceptibility to CHB.
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Affiliation(s)
- Hyun Sub Cheong
- Department of Genetic Epidemiology, SNP Genetics Inc., Sogang University, Seoul, Korea
| | - Jeong-Hoon Lee
- Department of Internal Medicine and Liver Research Institute, Seoul National University, Seoul, Korea
| | - Su Jong Yu
- Department of Internal Medicine and Liver Research Institute, Seoul National University, Seoul, Korea
| | - Jung-Hwan Yoon
- Department of Internal Medicine and Liver Research Institute, Seoul National University, Seoul, Korea
| | - Hyo-Suk Lee
- Department of Internal Medicine and Liver Research Institute, Seoul National University, Seoul, Korea
| | - Jae Youn Cheong
- Department of Gastroenterology, Ajou University School of Medicine, Suwon, Korea
| | - Sung Won Cho
- Department of Gastroenterology, Ajou University School of Medicine, Suwon, Korea
| | - Neung Hwa Park
- Department of Internal Medicine, Ulsan University Hospital, Ulsan, Korea
| | - Byung Lae Park
- Department of Genetic Epidemiology, SNP Genetics Inc., Sogang University, Seoul, Korea
| | - Suhg Namgoong
- Department of Genetic Epidemiology, SNP Genetics Inc., Sogang University, Seoul, Korea.,Department of Life Science, Sogang University, Seoul, Korea
| | - Lyoung Hyo Kim
- Department of Genetic Epidemiology, SNP Genetics Inc., Sogang University, Seoul, Korea.,Department of Life Science, Sogang University, Seoul, Korea
| | - Hyoung Doo Shin
- Department of Genetic Epidemiology, SNP Genetics Inc., Sogang University, Seoul, Korea.,Department of Life Science, Sogang University, Seoul, Korea
| | - Yoon-Jun Kim
- Department of Internal Medicine and Liver Research Institute, Seoul National University, Seoul, Korea
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30
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Holmbeck MA, Donner JR, Villa-Cuesta E, Rand DM. A Drosophila model for mito-nuclear diseases generated by an incompatible interaction between tRNA and tRNA synthetase. Dis Model Mech 2015; 8:843-54. [PMID: 26035388 PMCID: PMC4527286 DOI: 10.1242/dmm.019323] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 04/23/2015] [Indexed: 12/30/2022] Open
Abstract
Communication between the mitochondrial and nuclear genomes is vital for cellular function. The assembly of mitochondrial enzyme complexes, which produce the majority of cellular energy, requires the coordinated expression and translation of both mitochondrially and nuclear-encoded proteins. The joint genetic architecture of this system complicates the basis of mitochondrial diseases, and mutations both in mitochondrial DNA (mtDNA)- and nuclear-encoded genes have been implicated in mitochondrial dysfunction. Previously, in a set of mitochondrial-nuclear introgression strains, we characterized a dual genome epistasis in which a naturally occurring mutation in the Drosophila simulans simw(501) mtDNA-encoded transfer RNA (tRNA) for tyrosine (tRNA(Tyr)) interacts with a mutation in the nuclear-encoded mitochondrially localized tyrosyl-tRNA synthetase from Drosophila melanogaster. Here, we show that the incompatible mitochondrial-nuclear combination results in locomotor defects, reduced mitochondrial respiratory capacity, decreased oxidative phosphorylation (OXPHOS) enzyme activity and severe alterations in mitochondrial morphology. Transgenic rescue strains containing nuclear variants of the tyrosyl-tRNA synthetase are sufficient to rescue many of the deleterious phenotypes identified when paired with the simw(501) mtDNA. However, the severity of this defective mito-nuclear interaction varies across traits and genetic backgrounds, suggesting that the impact of mitochondrial dysfunction might be tissue specific. Because mutations in mitochondrial tRNA(Tyr) are associated with exercise intolerance in humans, this mitochondrial-nuclear introgression model in Drosophila provides a means to dissect the molecular basis of these, and other, mitochondrial diseases that are a consequence of the joint genetic architecture of mitochondrial function.
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Affiliation(s)
- Marissa A Holmbeck
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Julia R Donner
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | | | - David M Rand
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
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31
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Boczonadi V, Bansagi B, Horvath R. Reversible infantile mitochondrial diseases. J Inherit Metab Dis 2015; 38:427-35. [PMID: 25407320 DOI: 10.1007/s10545-014-9784-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 10/09/2014] [Accepted: 10/14/2014] [Indexed: 11/30/2022]
Abstract
Mitochondrial diseases are usually severe and progressive conditions; however, there are rare forms that show remarkable spontaneous recoveries. Two homoplasmic mitochondrial tRNA mutations (m.14674T>C/G in mt-tRNA(Glu)) have been reported to cause severe infantile mitochondrial myopathy in the first months of life. If these patients survive the first year of life by extensive life-sustaining measures they usually recover and develop normally. Another mitochondrial disease due to deficiency of the 5-methylaminomethyl-2-thiouridylate methyltransferase (TRMU) causes severe liver failure in infancy, but similar to the reversible mitochondrial myopathy, within the first year of life these infants may also recover completely. Partial recovery has been noted in some other rare forms of mitochondrial disease due to deficiency of mitochondrial tRNA synthetases and mitochondrial tRNA modifying enzymes. Here we summarize the clinical presentation of these unique reversible mitochondrial diseases and discuss potential molecular mechanisms behind the reversibility. Understanding these mechanisms may provide the key to treatments of potential broader relevance in mitochondrial disease, where for the majority of the patients no effective treatment is currently available.
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Affiliation(s)
- Veronika Boczonadi
- Institute of Human Genetics, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
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32
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Giordano C, Morea V, Perli E, d'Amati G. The phenotypic expression of mitochondrial tRNA-mutations can be modulated by either mitochondrial leucyl-tRNA synthetase or the C-terminal domain thereof. Front Genet 2015; 6:113. [PMID: 25852750 PMCID: PMC4370040 DOI: 10.3389/fgene.2015.00113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 03/04/2015] [Indexed: 11/23/2022] Open
Abstract
Mutations in mitochondrial (mt) DNA determine important human diseases. The majority of the known pathogenic mutations are located in transfer RNA (tRNA) genes and are responsible for a wide range of currently untreatable disorders. Experimental evidence both in yeast and in human cells has shown that the detrimental effects of mt-tRNA point mutations can be attenuated by increasing the expression of the cognate mt-aminoacyl-tRNA synthetases (aaRSs). In addition, constitutive high levels of isoleucyl-tRNA syntethase have been shown to reduce the penetrance of a homoplasmic mutation in mt-tRNAIle in a small kindred. More recently, we showed that the isolated carboxy-terminal domain of human mt-leucyl tRNA synthetase (LeuRS-Cterm) localizes to mitochondria and ameliorates the energetic defect in transmitochondrial cybrids carrying mutations either in the cognate mt-tRNALeu(UUR) or in the non-cognate mt-tRNAIle gene. Since the mt-LeuRS-Cterm does not possess catalytic activity, its rescuing ability is most likely mediated by a chaperon-like effect, consisting in the stabilization of the tRNA structure altered by the mutation. All together, these observations open potential therapeutic options for mt-tRNA mutations-associated diseases.
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Affiliation(s)
- Carla Giordano
- Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome Rome, Italy
| | - Veronica Morea
- National Research Council of Italy, Institute of Molecular Biology and Pathology, Department of Biochemical Sciences, Sapienza University of Rome Rome, Italy
| | - Elena Perli
- Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome Rome, Italy
| | - Giulia d'Amati
- Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome Rome, Italy ; Pasteur Institute-Cenci Bolognetti Foundation Rome, Italy
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33
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Viscomi C, Bottani E, Zeviani M. Emerging concepts in the therapy of mitochondrial disease. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:544-57. [PMID: 25766847 DOI: 10.1016/j.bbabio.2015.03.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 02/15/2015] [Accepted: 03/02/2015] [Indexed: 01/07/2023]
Abstract
Mitochondrial disorders are an important group of genetic conditions characterized by impaired oxidative phosphorylation. Mitochondrial disorders come with an impressive variability of symptoms, organ involvement, and clinical course, which considerably impact the quality of life and quite often shorten the lifespan expectancy. Although the last 20 years have witnessed an exponential increase in understanding the genetic and biochemical mechanisms leading to disease, this has not resulted in the development of effective therapeutic approaches, amenable of improving clinical course and outcome of these conditions to any significant extent. Therapeutic options for mitochondrial diseases still remain focused on supportive interventions aimed at relieving complications. However, new therapeutic strategies have recently been emerging, some of which have shown potential efficacy at the pre-clinical level. This review will present the state of the art on experimental therapy for mitochondrial disorders.
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Affiliation(s)
- Carlo Viscomi
- Unit of Molecular Neurogenetics, The Foundation "Carlo Besta" Institute of Neurology IRCCS, 20133 Milan, Italy; MRC-Mitochondrial Biology Unit, Cambridge CB2 0XY, UK.
| | | | - Massimo Zeviani
- Unit of Molecular Neurogenetics, The Foundation "Carlo Besta" Institute of Neurology IRCCS, 20133 Milan, Italy; MRC-Mitochondrial Biology Unit, Cambridge CB2 0XY, UK.
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Di Micco P, Fazzi D'Orsi M, Morea V, Frontali L, Francisci S, Montanari A. The yeast model suggests the use of short peptides derived from mt LeuRS for the therapy of diseases due to mutations in several mt tRNAs. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:3065-74. [PMID: 25261707 DOI: 10.1016/j.bbamcr.2014.09.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 09/09/2014] [Accepted: 09/11/2014] [Indexed: 01/23/2023]
Abstract
We have previously established a yeast model of mitochondrial (mt) diseases. We showed that defective respiratory phenotypes due to point-mutations in mt tRNA(Leu(UUR)), tRNA(Ile) and tRNA(Val) could be relieved by overexpression of both cognate and non-cognate nuclearly encoded mt aminoacyl-tRNA synthetases (aaRS) LeuRS, IleRS and ValRS. More recently, we showed that the isolated carboxy-terminal domain (Cterm) of yeast mt LeuRS, and even short peptides derived from the human Cterm, have the same suppressing abilities as the whole enzymes. In this work, we extend these results by investigating the activity of a number of mt aaRS from either class I or II towards a panel of mt tRNAs. The Cterm of both human and yeast mt LeuRS has the same spectrum of activity as mt aaRS belonging to class I and subclass a, which is the most extensive among the whole enzymes. Yeast Cterm is demonstrated to be endowed with mt targeting activity. Importantly, peptide fragments β30_31 and β32_33, derived from the human Cterm, have even higher efficiency as well as wider spectrum of activity, thus opening new avenues for therapeutic intervention. Bind-shifting experiments show that the β30_31 peptide directly interacts with human mt tRNA(Leu(UUR)) and tRNA(Ile), suggesting that the rescuing activity of isolated peptide fragments is mediated by a chaperone-like mechanism. Wide-range suppression appears to be idiosyncratic of LeuRS and its fragments, since it is not shared by Cterminal regions derived from human mt IleRS or ValRS, which are expected to have very different structures and interactions with tRNAs.
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Affiliation(s)
- Patrizio Di Micco
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy
| | - Mario Fazzi D'Orsi
- Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy
| | - Veronica Morea
- National Research Council of Italy (CNR) - Institute of Biology, Molecular Medicine and Nanobiotechnology (IBMN), Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy
| | - Laura Frontali
- Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy; Pasteur Institute - Cenci Bolognetti Foundation, Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy
| | - Silvia Francisci
- Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy; Pasteur Institute - Cenci Bolognetti Foundation, Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy
| | - Arianna Montanari
- Department of Biology and Biotechnologies "C. Darwin", Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy.
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Perli E, Giordano C, Pisano A, Montanari A, Campese AF, Reyes A, Ghezzi D, Nasca A, Tuppen HA, Orlandi M, Di Micco P, Poser E, Taylor RW, Colotti G, Francisci S, Morea V, Frontali L, Zeviani M, d'Amati G. The isolated carboxy-terminal domain of human mitochondrial leucyl-tRNA synthetase rescues the pathological phenotype of mitochondrial tRNA mutations in human cells. EMBO Mol Med 2014; 6:169-82. [PMID: 24413190 PMCID: PMC3927953 DOI: 10.1002/emmm.201303198] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/16/2013] [Accepted: 10/17/2013] [Indexed: 11/16/2022] Open
Abstract
Mitochondrial (mt) diseases are multisystem disorders due to mutations in nuclear or mtDNA genes. Among the latter, more than 50% are located in transfer RNA (tRNA) genes and are responsible for a wide range of syndromes, for which no effective treatment is available at present. We show that three human mt aminoacyl-tRNA syntethases, namely leucyl-, valyl-, and isoleucyl-tRNA synthetase are able to improve both viability and bioenergetic proficiency of human transmitochondrial cybrid cells carrying pathogenic mutations in the mt-tRNA(Ile) gene. Importantly, we further demonstrate that the carboxy-terminal domain of human mt leucyl-tRNA synthetase is both necessary and sufficient to improve the pathologic phenotype associated either with these "mild" mutations or with the "severe" m.3243A>G mutation in the mt-tRNA(L)(eu(UUR)) gene. Furthermore, we provide evidence that this small, non-catalytic domain is able to directly and specifically interact in vitro with human mt-tRNA(Leu(UUR)) with high affinity and stability and, with lower affinity, with mt-tRNA(Ile). Taken together, our results sustain the hypothesis that the carboxy-terminal domain of human mt leucyl-tRNA synthetase can be used to correct mt dysfunctions caused by mt-tRNA mutations.
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Affiliation(s)
- Elena Perli
- Department of Radiology, Oncology and Pathology, Sapienza University of RomeRome, Italy
- Pasteur Institute-Cenci Bolognetti FoundationRome, Italy
| | - Carla Giordano
- Department of Radiology, Oncology and Pathology, Sapienza University of RomeRome, Italy
| | - Annalinda Pisano
- Department of Radiology, Oncology and Pathology, Sapienza University of RomeRome, Italy
- Department of Internal Medicine and Medical Specialties, Sapienza University of RomeRome, Italy
| | - Arianna Montanari
- Department of Radiology, Oncology and Pathology, Sapienza University of RomeRome, Italy
- Pasteur Institute-Cenci Bolognetti FoundationRome, Italy
- Department of Biology and Biotechnologies ‘Charles Darwin’, Sapienza University of RomeRome, Italy
| | - Antonio F Campese
- Department of Molecular Medicine, Sapienza University of RomeRome, Italy
| | | | - Daniele Ghezzi
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology IRCCSMilan, Italy
| | - Alessia Nasca
- Unit of Molecular Neurogenetics, The Foundation “Carlo Besta” Institute of Neurology IRCCSMilan, Italy
| | - Helen A Tuppen
- Wellcome Trust Center for Mitochondrial Research, Institute for Ageing and Health, Newcastle UniversityNewcastle upon Tyne, UK
| | - Maurizia Orlandi
- Department of Radiology, Oncology and Pathology, Sapienza University of RomeRome, Italy
- Department of Molecular Medicine, Sapienza University of RomeRome, Italy
| | - Patrizio Di Micco
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of RomeRome, Italy
| | - Elena Poser
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of RomeRome, Italy
| | - Robert W Taylor
- Wellcome Trust Center for Mitochondrial Research, Institute for Ageing and Health, Newcastle UniversityNewcastle upon Tyne, UK
| | - Gianni Colotti
- National Research Council of Italy, Institute of Molecular Biology and PathologyRome, Italy
| | - Silvia Francisci
- Pasteur Institute-Cenci Bolognetti FoundationRome, Italy
- Department of Biology and Biotechnologies ‘Charles Darwin’, Sapienza University of RomeRome, Italy
| | - Veronica Morea
- National Research Council of Italy, Institute of Molecular Biology and PathologyRome, Italy
| | - Laura Frontali
- Pasteur Institute-Cenci Bolognetti FoundationRome, Italy
- Department of Biology and Biotechnologies ‘Charles Darwin’, Sapienza University of RomeRome, Italy
| | | | - Giulia d'Amati
- Department of Radiology, Oncology and Pathology, Sapienza University of RomeRome, Italy
- Pasteur Institute-Cenci Bolognetti FoundationRome, Italy
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Pathological Mutations of the Mitochondrial Human Genome: the Instrumental Role of the Yeast S. cerevisiae. Diseases 2014. [DOI: 10.3390/diseases2010024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Idiosyncrasies in decoding mitochondrial genomes. Biochimie 2014; 100:95-106. [PMID: 24440477 DOI: 10.1016/j.biochi.2014.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 01/06/2014] [Indexed: 11/24/2022]
Abstract
Mitochondria originate from the α-proteobacterial domain of life. Since this unique event occurred, mitochondrial genomes of protozoans, fungi, plants and metazoans have highly derived and diverged away from the common ancestral DNA. These resulting genomes highly differ from one another, but all present-day mitochondrial DNAs have a very reduced coding capacity. Strikingly however, ATP production coupled to electron transport and translation of mitochondrial proteins are the two common functions retained in all mitochondrial DNAs. Paradoxically, most components essential for these two functions are now expressed from nuclear genes. Understanding how mitochondrial translation evolved in various eukaryotic models is essential to acquire new knowledge of mitochondrial genome expression. In this review, we provide a thorough analysis of the idiosyncrasies of mitochondrial translation as they occur between organisms. We address this by looking at mitochondrial codon usage and tRNA content. Then, we look at the aminoacyl-tRNA-forming enzymes in terms of peculiarities, dual origin, and alternate function(s). Finally we give examples of the atypical structural properties of mitochondrial tRNAs found in some organisms and the resulting adaptive tRNA-protein partnership.
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Hornig-Do HT, Montanari A, Rozanska A, Tuppen HA, Almalki AA, Abg-Kamaludin DP, Frontali L, Francisci S, Lightowlers RN, Chrzanowska-Lightowlers ZM. Human mitochondrial leucyl tRNA synthetase can suppress non cognate pathogenic mt-tRNA mutations. EMBO Mol Med 2014; 6:183-93. [PMID: 24413189 PMCID: PMC3927954 DOI: 10.1002/emmm.201303202] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Disorders of the mitochondrial genome cause a wide spectrum of disease, these present mainly as neurological and/or muscle related pathologies. Due to the intractability of the human mitochondrial genome there are currently no effective treatments for these disorders. The majority of the pathogenic mutations lie in the genes encoding mitochondrial tRNAs. Consequently, the biochemical deficiency is due to mitochondrial protein synthesis defects, which manifest as aberrant cellular respiration and ATP synthesis. It has previously been reported that overexpression of mitochondrial aminoacyl tRNA synthetases has been effective, in cell lines, at partially suppressing the defects resulting from mutations in their cognate mt-tRNAs. We now show that leucyl tRNA synthetase is able to partially rescue defects caused by mutations in non-cognate mt-tRNAs. Further, a C terminal peptide alone can enter mitochondria and interact with the same spectrum of mt-tRNAs as the entire synthetase, in intact cells. These data support the possibility that a small peptide could correct at least the biochemical defect associated with many mt-tRNA mutations, inferring a novel therapy for these disorders.
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Affiliation(s)
- Hue Tran Hornig-Do
- The Wellcome Trust Centre for Mitochondrial Research Institute for Ageing and Health The Medical School, Newcastle University, Newcastle upon Tyne, UK
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Almalki A, Alston CL, Parker A, Simonic I, Mehta SG, He L, Reza M, Oliveira JM, Lightowlers RN, McFarland R, Taylor RW, Chrzanowska-Lightowlers ZM. Mutation of the human mitochondrial phenylalanine-tRNA synthetase causes infantile-onset epilepsy and cytochrome c oxidase deficiency. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1842:56-64. [PMID: 24161539 PMCID: PMC3898479 DOI: 10.1016/j.bbadis.2013.10.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 09/30/2013] [Accepted: 10/17/2013] [Indexed: 11/24/2022]
Abstract
Mitochondrial aminoacyl-tRNA synthetases (aaRSs) are essential enzymes in protein synthesis since they charge tRNAs with their cognate amino acids. Mutations in the genes encoding mitochondrial aaRSs have been associated with a wide spectrum of human mitochondrial diseases. Here we report the identification of pathogenic mutations (a partial genomic deletion and a highly conserved p. Asp325Tyr missense variant) in FARS2, the gene encoding mitochondrial phenylalanyl-tRNA synthetase, in a patient with early-onset epilepsy and isolated complex IV deficiency in muscle. The biochemical defect was expressed in myoblasts but not in fibroblasts and associated with decreased steady state levels of COXI and COXII protein and reduced steady state levels of the mt-tRNA(Phe) transcript. Functional analysis of the recombinant mutant p. Asp325Tyr FARS2 protein showed an inability to bind ATP and consequently undetectable aminoacylation activity using either bacterial tRNA or human mt-tRNA(Phe) as substrates. Lentiviral transduction of cells with wildtype FARS2 restored complex IV protein levels, confirming that the p.Asp325Tyr mutation is pathogenic, causing respiratory chain deficiency and neurological deficits on account of defective aminoacylation of mt-tRNA(Phe).
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Affiliation(s)
- Abdulraheem Almalki
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Charlotte L. Alston
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Alasdair Parker
- Child Development Centre, Addenbrooke's Hospital, Cambridge, UK
| | - Ingrid Simonic
- Medical Genetics Laboratories, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Sarju G. Mehta
- Department of Medical Genetics, Addenbrookes Hospital, Cambridge, UK
| | - Langping He
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Mojgan Reza
- Biobank, Institute for Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
| | - Jorge M.A. Oliveira
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Robert N. Lightowlers
- The Wellcome Trust Centre for Mitochondrial Research, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Robert McFarland
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Robert W. Taylor
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Zofia M.A. Chrzanowska-Lightowlers
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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Abstract
The Escherichia coli oligoribonuclease, ORN, has a 3′ to 5′ exonuclease activity specific for small oligomers that is essential for cell viability. The human homologue, REXO2, has hitherto been incompletely characterized, with only its in vitro ability to degrade small single-stranded RNA and DNA fragments documented. Here we show that the human enzyme has clear dual cellular localization being present both in cytosolic and mitochondrial fractions. Interestingly, the mitochondrial form localizes to both the intermembrane space and the matrix. Depletion of REXO2 by RNA interference causes a strong morphological phenotype in human cells, which show a disorganized network of punctate and granular mitochondria. Lack of REXO2 protein also causes a substantial decrease of mitochondrial nucleic acid content and impaired de novo mitochondrial protein synthesis. Our data constitute the first in vivo evidence for an oligoribonuclease activity in human mitochondria.
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Kam WWY, Lake V, Banos C, Davies J, Banati R. Apparent polyploidization after gamma irradiation: pitfalls in the use of quantitative polymerase chain reaction (qPCR) for the estimation of mitochondrial and nuclear DNA gene copy numbers. Int J Mol Sci 2013; 14:11544-59. [PMID: 23722662 PMCID: PMC3709747 DOI: 10.3390/ijms140611544] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 04/18/2013] [Accepted: 05/16/2013] [Indexed: 12/12/2022] Open
Abstract
Quantitative polymerase chain reaction (qPCR) has been widely used to quantify changes in gene copy numbers after radiation exposure. Here, we show that gamma irradiation ranging from 10 to 100 Gy of cells and cell-free DNA samples significantly affects the measured qPCR yield, due to radiation-induced fragmentation of the DNA template and, therefore, introduces errors into the estimation of gene copy numbers. The radiation-induced DNA fragmentation and, thus, measured qPCR yield varies with temperature not only in living cells, but also in isolated DNA irradiated under cell-free conditions. In summary, the variability in measured qPCR yield from irradiated samples introduces a significant error into the estimation of both mitochondrial and nuclear gene copy numbers and may give spurious evidence for polyploidization.
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Affiliation(s)
- Winnie W. Y. Kam
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, New South Wales 2234, Australia; E-Mails: (V.L.); (C.B.); (J.D.); (R.B.)
- Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, Cumberland, Sydney, New South Wales 2141, Australia
- Author to whom correspondence should be addressed; E-Mail: or ; Tel.: +61-2-9717-7241; Fax: +61-2-9717-9262
| | - Vanessa Lake
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, New South Wales 2234, Australia; E-Mails: (V.L.); (C.B.); (J.D.); (R.B.)
| | - Connie Banos
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, New South Wales 2234, Australia; E-Mails: (V.L.); (C.B.); (J.D.); (R.B.)
| | - Justin Davies
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, New South Wales 2234, Australia; E-Mails: (V.L.); (C.B.); (J.D.); (R.B.)
- School of Physics, University of Sydney, Camperdown, Sydney, New South Wales 2006, Australia
| | - Richard Banati
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Sydney, New South Wales 2234, Australia; E-Mails: (V.L.); (C.B.); (J.D.); (R.B.)
- Medical Radiation Sciences, Faculty of Health Sciences, University of Sydney, Cumberland, Sydney, New South Wales 2141, Australia
- National Imaging Facility at Brain and Mind Research Institute (BMRI), University of Sydney, Camperdown, Sydney, New South Wales 2050, Australia
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Montanari A, Zhou YF, D'Orsi MF, Bolotin-Fukuhara M, Frontali L, Francisci S. Analyzing the suppression of respiratory defects in the yeast model of human mitochondrial tRNA diseases. Gene 2013; 527:1-9. [PMID: 23727608 DOI: 10.1016/j.gene.2013.05.042] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 04/29/2013] [Accepted: 05/13/2013] [Indexed: 12/01/2022]
Abstract
The respiratory defects associated with mutations in human mitochondrial tRNA genes can be mimicked in yeast, which is the only organism easily amenable to mitochondrial transformation. This approach has shown that overexpression of several nuclear genes coding for factors involved in mitochondrial protein synthesis can alleviate the respiratory defects both in yeast and in human cells. The present paper analyzes in detail the effects of overexpressed yeast and human mitochondrial translation elongation factors EF-Tu. We studied the suppressing activity versus the function in mt translation of mutated versions of this factor and we obtained indications on the mechanism of suppression. Moreover from a more extended search for suppressor genes we isolated factors which might be active in mitochondrial biogenesis. Results indicate that the multiplicity of mitochondrial factors as well as their high variability of expression levels can account for the variable severity of mitochondrial diseases and might suggest possible therapeutic approaches.
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Affiliation(s)
- Arianna Montanari
- Department of Biology and Biotechnologies C. Darwin, Pasteur Institute-Cenci Bolognetti Foundation, Sapienza University of Rome, Piazzale A. Moro 5, 00185 Rome, Italy
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Green fluorescent protein alters the transcriptional regulation of human mitochondrial genes after gamma irradiation. J Fluoresc 2013; 23:613-9. [PMID: 23475276 DOI: 10.1007/s10895-013-1206-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 02/24/2013] [Indexed: 12/21/2022]
Abstract
Green fluorescent proteins (GFP), extensively used as reporters in biological and imaging studies, are assumed to be mostly biologically inert. Here, we test the assumption in regard to the transcriptional regulation of 18 mitochondrially encoded genes in GFP expressing human T-cell line (JURKAT cells) exposed to gamma radiation. Using quantitative polymerase chain reaction, we demonstrate that wild type and GFP expressing JURKAT cells have different baseline mitochondrial transcript expression (10 out of the 18 tested genes) and after a single dose of radiation (100 Gy) show a significantly different transcriptional regulation of their mitochondrial genes. While in wild type cells, ten of the tested genes are up-regulated in response to radiation exposure, GFP expressing cells show less transcriptional regulation with a small down-regulation in five genes. Our results indicate that the presence of GFP in the cytoplasm can alter the cellular response to ionizing radiation.
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Defective valyl-tRNA synthetase hampers the mitochondrial respiratory chain in Neurospora crassa. Biochem J 2012; 448:297-306. [PMID: 22957697 DOI: 10.1042/bj20120963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Respiratory chain deficiency can result from alterations in mitochondrial and/or cytosolic protein synthesis due to the dual genetic origin of mitochondrial oxidative phosphorylation. In the present paper we report a point mutation (D750G) in the bifunctional VARS (valyl-tRNA synthetase) of the fungus Neurospora crassa, associated with a temperature-sensitive phenotype. Analysis of the mutant strain revealed decreased steady-state levels of VARS and a clear reduction in the rate of mitochondrial protein synthesis. We observed a robust induction of the mitochondrial alternative oxidase with a concomitant decrease in the canonical respiratory pathway, namely in cytochrome b and aa3 content. Furthermore, the mutant strain accumulates the peripheral arm of complex I and depicts decreased levels of complexes III and IV, consistent with severe impairment of the mitochondrial respiratory chain. The phenotypic alterations of the mutant strain are observed at the permissive growth temperature and exacerbated upon increase of the temperature. Surprisingly, glucose-6-phosphate dehydrogenase activities were similar in the wild-type and mutant strains, whereas mitochondrial activities for succinate dehydrogenase and alternative NADH dehydrogenases were increased in the mutant strain, suggesting that the VARSD-G mutation does not affect overall cytosolic protein synthesis. Expression of the wild-type vars gene rescues all of the mutant phenotypes, indicating that the VARSD-G mutation is a loss-of-function mutation that results in a combined respiratory chain deficiency.
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Sangatsuda Y, Nakamura M, Tomiyasu A, Deguchi A, Toyota Y, Goto YI, Nishino I, Ueno SI, Sano A. Heteroplasmic m.1624C>T mutation of the mitochondrial tRNA(Val) gene in a proband and his mother with repeated consciousness disturbances. Mitochondrion 2012; 12:617-22. [PMID: 23063709 DOI: 10.1016/j.mito.2012.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/03/2012] [Accepted: 10/02/2012] [Indexed: 10/27/2022]
Abstract
Homoplasmic m.1624C>T mutation of the mitochondrial tRNA(Val) gene was previously demonstrated to cause fatal neonatal Leigh syndrome. Here, we report the clinical phenotypes of a Japanese male and his mother with heteroplasmic m.1624C>T mutation. The 36-year-old male presented with repeated episodes of consciousness disturbance since the age of 25, cognitive decline, and personality change. Cerebrospinal fluid levels of lactate and pyruvate were elevated. His mother showed similar symptoms and course. The mutation m.1624C>T was identified heteroplasmically in the proband's muscle and leukocytes and in the mother's leukocytes. The heteroplasmy load decreased with age.
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Affiliation(s)
- Yoko Sangatsuda
- Department of Psychiatry, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan.
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del Mar O'Callaghan M, Emperador S, López-Gallardo E, Jou C, Buján N, Montero R, Garcia-Cazorla A, Gonzaga D, Ferrer I, Briones P, Ruiz-Pesini E, Pineda M, Artuch R, Montoya J. New mitochondrial DNA mutations in tRNA associated with three severe encephalopamyopathic phenotypes: neonatal, infantile, and childhood onset. Neurogenetics 2012; 13:245-50. [PMID: 22638997 DOI: 10.1007/s10048-012-0322-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Accepted: 03/10/2012] [Indexed: 01/03/2023]
Abstract
The reported cases showed clinical, biochemical, histopathological, and molecular features lending support to the hypothesis of a pathogenic effect of the detected mutations. Case 1 was a neonatal presentation who showed multiple mitochondrial respiratory chain enzyme defects in muscle associated with a new homoplasmic m.5514A > G transition in the tRNA(Trp) gene. Case 2 was a late infantile presentation who also showed mitochondrial respiratory chain enzyme deficiencies in muscle together with a new m.1643A > G tRNA(Val) mutation in homoplasmy. Case 3 showed a MERRF phenotype presented in childhood associated with the once previously reported m.15923A > G mutation in heteroplasmy in all the tissues studied.
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Affiliation(s)
- María del Mar O'Callaghan
- Department of Pediatric Neurology, Hospital Sant Joan de Déu, Passeig Sant Joan de Déu 2, 08950 Esplugues, Barcelona, Spain.
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Wenz T, Wang X, Marini M, Moraes CT. A metabolic shift induced by a PPAR panagonist markedly reduces the effects of pathogenic mitochondrial tRNA mutations. J Cell Mol Med 2012; 15:2317-25. [PMID: 21129152 PMCID: PMC3361135 DOI: 10.1111/j.1582-4934.2010.01223.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Mutations in mitochondrial DNA-encoded tRNA genes are associated with many human diseases. Activation of peroxisome proliferator-activated receptors (PPARs) by synthetic agonists stimulates oxidative metabolism, induces an increase in mitochondrial mass and partially compensates for oxidative phosphorylation system (OXPHOS) defects caused by single OXPHOS enzyme deficiencies in vitro and in vivo. Here, we analysed whether treatment with the PPAR panagonist bezafibrate in cybrids homoplasmic for different mitochondrial tRNA mutations could ameliorate the OXPHOS defect. We found that bezafibrate treatment increased mitochondrial mass, mitochondrial tRNA steady state levels and enhanced mitochondrial protein synthesis. This improvement resulted in increased OXPHOS activity and finally in enhanced mitochondrial ATP generating capacity. PPAR panagonists are known to increase the expression of PPAR gamma coactivator-1α (PGC-1α), a master regulator of mitochondrial biogenesis. Accordingly, we found that clones of a line harbouring a mutated mitochondrial tRNA gene mutation selected for the ability to grow in a medium selective for OXPHOS function had a 3-fold increase in PGC-1α expression, an increase that was similar to the one observed after bezafibrate treatment. These findings show that increasing mitochondrial mass and thereby boosting residual OXPHOS capacity can be beneficial to an important class of mitochondrial defects reinforcing the potential therapeutic use of approaches stimulating mitochondrial proliferation for mitochondrial disorders.
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Affiliation(s)
- Tina Wenz
- Department of Neurology, University of Miami School of Medicine, Miami, FL 33136, USA
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Belostotsky R, Frishberg Y, Entelis N. Human mitochondrial tRNA quality control in health and disease: a channelling mechanism? RNA Biol 2012; 9:33-9. [PMID: 22258151 DOI: 10.4161/rna.9.1.18009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Mutations in human mitochondrial tRNA genes are associated with a number of multisystemic disorders. These single nucleotide substitutions in various domains of tRNA molecules may affect different steps of tRNA biogenesis. Often, the prominent decrease of aminoacylation and/or steady-state levels of affected mitochondrial tRNA have been demonstrated in patients' tissues and in cultured cells. Similar effect has been observed for pathogenic mutations in nuclear genes encoding mitochondrial aminoacyl-tRNA-synthetases, while over-expression of mitochondrial aminoacyl-tRNA synthetases or elongation factor EF-Tu rescued mutated tRNAs from degradation. In this review we summarize experimental data concerning the possible regulatory mechanisms governing mitochondrial tRNA steady-state levels, and propose a hypothesis based on the tRNA channelling principle. According to this hypothesis, interaction of mitochondrial tRNA with proteins ensures not only tRNA synthesis, maturation and function, but also protection from degradation. Mutations perturbing this interaction lead to decreased tRNA stability.
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Affiliation(s)
- Ruth Belostotsky
- Division of Pediatric Nephrology, Shaare Zedek Medical Center; Jerusalem, Israel
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Montanari A, De Luca C, Di Micco P, Morea V, Frontali L, Francisci S. Structural and functional role of bases 32 and 33 in the anticodon loop of yeast mitochondrial tRNAIle. RNA (NEW YORK, N.Y.) 2011; 17:1983-1996. [PMID: 21914842 PMCID: PMC3198592 DOI: 10.1261/rna.2878711] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 07/20/2011] [Indexed: 05/31/2023]
Abstract
Previous work has demonstrated the usefulness of the yeast model to investigate the molecular mechanisms underlying defects due to base substitutions in mitochondrial tRNA genes, and to identify suppressing molecules endowed with potential clinical relevance. The present paper extends these investigations to two human equivalent yeast mutations located at positions 32 and 33 in the anticodon loop of tRNA(Ile). Notwithstanding the proximity of the two T>C base substitutions, the effects of these mutations have been found to be quite different in yeast, as they are in human. The T32C substitution has a very severe effect in yeast, consisting in a complete inhibition of growth on nonfermentable substrates. Conversely, respiratory defects caused by the T33C mutation could only be observed in a defined genetic context. Analyses of available sequences and selected tRNA three-dimensional structures were performed to provide explanations for the different behavior of these adjacent mutations. Examination of the effects of previously identified suppressors demonstrated that overexpression of the TUF1 gene did not rescue the defective phenotypes determined by either mutation, possibly as a consequence of the lack of interactions between EF-Tu and the tRNA anticodon arm in known structures. On the contrary, both the cognate IleRS and the noncognate LeuRS and ValRS are endowed with suppressing activities toward both mutations. This allows us to extend to the tRNA(Ile) mutants the cross-suppression activity of aminoacyl-tRNA synthetases previously demonstrated for tRNA(Leu) and tRNA(Val) mutants.
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Affiliation(s)
- Arianna Montanari
- Department of Biology and Biotechnology, Pasteur Institute, Cenci Bolognetti Foundation, Sapienza University of Rome, 00185 Rome, Italy
| | - Cristina De Luca
- Department of Biology and Biotechnology, Pasteur Institute, Cenci Bolognetti Foundation, Sapienza University of Rome, 00185 Rome, Italy
| | - Patrizio Di Micco
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, 00185 Rome, Italy
| | - Veronica Morea
- CNR—National Research Council of Italy, Institute of Molecular Biology and Pathology, 00185 Rome, Italy
| | - Laura Frontali
- Department of Biology and Biotechnology, Pasteur Institute, Cenci Bolognetti Foundation, Sapienza University of Rome, 00185 Rome, Italy
| | - Silvia Francisci
- Department of Biology and Biotechnology, Pasteur Institute, Cenci Bolognetti Foundation, Sapienza University of Rome, 00185 Rome, Italy
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Arredondo JJ, Gallardo ME, García-Pavía P, Domingo V, Bretón B, García-Silva MT, Sedano MJ, Martín MA, Arenas J, Cervera M, Garesse R, Bornstein B. Mitochondrial tRNA valine as a recurrent target for mutations involved in mitochondrial cardiomyopathies. Mitochondrion 2011; 12:357-62. [PMID: 21986556 DOI: 10.1016/j.mito.2011.09.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 09/15/2011] [Accepted: 09/20/2011] [Indexed: 11/28/2022]
Abstract
The aim of this study was to identify the genetic defect in two patients having cardiac dysfunction accompanied by neurological symptoms, and in one case MRI evidence of cortical and cerebellar atrophy with hyperintensities in the basal ganglia. Muscle biopsies from each patient revealed single and combined mitochondrial respiratory chain deficiency. The complete mtDNA sequencing of both patients revealed two transitions in the mitochondrial tRNA(Val) gene (MT-TV) (m.1628C>T in Patient 1, and m.1644G>A in Patient 2). The functional and molecular analyses reported here suggest that the MT-TV gene should be routinely considered in the diagnosis of mitochondrial cardiomyopathies.
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Affiliation(s)
- Juan J Arredondo
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas Alberto Sols CSIC-UAM, Facultad de Medicina, Universidad Autónoma de Madrid, Spain
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