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Ramos-Acosta C, Huerta-Pantoja L, Salazar-Hidalgo ME, Mayol E, Jiménez-Vega S, García-Peña P, Jordi-Cruz J, Baquero C, Porras A, Íñigo-Rodríguez B, Benavente CM, López-Pastor AR, Gómez-Delgado I, Urcelay E, Candel FJ, Anguita E. Tigecycline Opposes Bortezomib Effect on Myeloma Cells Decreasing Mitochondrial Reactive Oxygen Species Production. Int J Mol Sci 2024; 25:4887. [PMID: 38732105 PMCID: PMC11084384 DOI: 10.3390/ijms25094887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/23/2024] [Accepted: 04/27/2024] [Indexed: 05/13/2024] Open
Abstract
Multiple myeloma is an incurable plasma cell malignancy. Most patients end up relapsing and developing resistance to antineoplastic drugs, like bortezomib. Antibiotic tigecycline has activity against myeloma. This study analyzed tigecycline and bortezomib combination on cell lines and plasma cells from myeloma patients. Apoptosis, autophagic vesicles, mitochondrial mass, mitochondrial superoxide, cell cycle, and hydrogen peroxide were studied by flow cytometry. In addition, mitochondrial antioxidants and electron transport chain complexes were quantified by reverse transcription real-time PCR (RT-qPCR) or western blot. Cell metabolism and mitochondrial activity were characterized by Seahorse and RT-qPCR. We found that the addition of tigecycline to bortezomib reduces apoptosis in proportion to tigecycline concentration. Supporting this, the combination of both drugs counteracts bortezomib in vitro individual effects on the cell cycle, reduces autophagy and mitophagy markers, and reverts bortezomib-induced increase in mitochondrial superoxide. Changes in mitochondrial homeostasis and MYC upregulation may account for some of these findings. These data not only advise to avoid considering tigecycline and bortezomib combination for treating myeloma, but caution on the potential adverse impact of treating infections with this antibiotic in myeloma patients under bortezomib treatment.
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Affiliation(s)
- Carlos Ramos-Acosta
- Department of Medicine, Medical School, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, 28040 Madrid, Spain (E.M.); (S.J.-V.); (J.J.-C.); (C.M.B.); (F.J.C.)
- Hematology Department, IML, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Profesor Martín Lagos s/n, 28040 Madrid, Spain (B.Í.-R.)
| | - Laura Huerta-Pantoja
- Department of Medicine, Medical School, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, 28040 Madrid, Spain (E.M.); (S.J.-V.); (J.J.-C.); (C.M.B.); (F.J.C.)
- Hematology Department, IML, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Profesor Martín Lagos s/n, 28040 Madrid, Spain (B.Í.-R.)
| | - Milton Eduardo Salazar-Hidalgo
- Hematology Department, IML, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Profesor Martín Lagos s/n, 28040 Madrid, Spain (B.Í.-R.)
| | - Elsa Mayol
- Department of Medicine, Medical School, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, 28040 Madrid, Spain (E.M.); (S.J.-V.); (J.J.-C.); (C.M.B.); (F.J.C.)
- Hematology Department, IML, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Profesor Martín Lagos s/n, 28040 Madrid, Spain (B.Í.-R.)
| | - Selene Jiménez-Vega
- Department of Medicine, Medical School, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, 28040 Madrid, Spain (E.M.); (S.J.-V.); (J.J.-C.); (C.M.B.); (F.J.C.)
- Hematology Department, IML, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Profesor Martín Lagos s/n, 28040 Madrid, Spain (B.Í.-R.)
| | - Pablo García-Peña
- Department of Medicine, Medical School, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, 28040 Madrid, Spain (E.M.); (S.J.-V.); (J.J.-C.); (C.M.B.); (F.J.C.)
- Hematology Department, IML, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Profesor Martín Lagos s/n, 28040 Madrid, Spain (B.Í.-R.)
| | - Jenifeer Jordi-Cruz
- Department of Medicine, Medical School, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, 28040 Madrid, Spain (E.M.); (S.J.-V.); (J.J.-C.); (C.M.B.); (F.J.C.)
- Hematology Department, IML, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Profesor Martín Lagos s/n, 28040 Madrid, Spain (B.Í.-R.)
| | - Cristina Baquero
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Universidad Complutense de Madrid (UCM), Instituto de Investigación Sanitaria San Carlos (IdISSC), 28040 Madrid, Spain; (C.B.); (A.P.)
| | - Almudena Porras
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Universidad Complutense de Madrid (UCM), Instituto de Investigación Sanitaria San Carlos (IdISSC), 28040 Madrid, Spain; (C.B.); (A.P.)
| | - Belén Íñigo-Rodríguez
- Hematology Department, IML, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Profesor Martín Lagos s/n, 28040 Madrid, Spain (B.Í.-R.)
| | - Celina M. Benavente
- Department of Medicine, Medical School, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, 28040 Madrid, Spain (E.M.); (S.J.-V.); (J.J.-C.); (C.M.B.); (F.J.C.)
- Hematology Department, IML, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Profesor Martín Lagos s/n, 28040 Madrid, Spain (B.Í.-R.)
| | - Andrea R. López-Pastor
- Laboratory of Genetics and Molecular Bases of Complex Diseases, Instituto de Investigación Sanitaria San Carlos (IdISSC), 28040 Madrid, Spain; (A.R.L.-P.); (I.G.-D.); (E.U.)
- Networks for Cooperative Research in Health Results (RICORS, REI), 28089 Madrid, Spain
| | - Irene Gómez-Delgado
- Laboratory of Genetics and Molecular Bases of Complex Diseases, Instituto de Investigación Sanitaria San Carlos (IdISSC), 28040 Madrid, Spain; (A.R.L.-P.); (I.G.-D.); (E.U.)
- Networks for Cooperative Research in Health Results (RICORS, REI), 28089 Madrid, Spain
| | - Elena Urcelay
- Laboratory of Genetics and Molecular Bases of Complex Diseases, Instituto de Investigación Sanitaria San Carlos (IdISSC), 28040 Madrid, Spain; (A.R.L.-P.); (I.G.-D.); (E.U.)
- Networks for Cooperative Research in Health Results (RICORS, REI), 28089 Madrid, Spain
| | - Francisco Javier Candel
- Department of Medicine, Medical School, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, 28040 Madrid, Spain (E.M.); (S.J.-V.); (J.J.-C.); (C.M.B.); (F.J.C.)
- Clinical Microbiology & Infectious Diseases, Transplant Coordination, IML, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, 28040 Madrid, Spain
| | - Eduardo Anguita
- Department of Medicine, Medical School, Universidad Complutense de Madrid (UCM), Plaza Ramón y Cajal s/n, 28040 Madrid, Spain (E.M.); (S.J.-V.); (J.J.-C.); (C.M.B.); (F.J.C.)
- Hematology Department, IML, Instituto de Investigación Sanitaria San Carlos (IdISSC), Hospital Clínico San Carlos, Profesor Martín Lagos s/n, 28040 Madrid, Spain (B.Í.-R.)
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Vila-Sanjurjo A, Mallo N, Atkins JF, Elson JL, Smith PM. Our current understanding of the toxicity of altered mito-ribosomal fidelity during mitochondrial protein synthesis: What can it tell us about human disease? Front Physiol 2023; 14:1082953. [PMID: 37457031 PMCID: PMC10349377 DOI: 10.3389/fphys.2023.1082953] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/28/2023] [Indexed: 07/18/2023] Open
Abstract
Altered mito-ribosomal fidelity is an important and insufficiently understood causative agent of mitochondrial dysfunction. Its pathogenic effects are particularly well-known in the case of mitochondrially induced deafness, due to the existence of the, so called, ototoxic variants at positions 847C (m.1494C) and 908A (m.1555A) of 12S mitochondrial (mt-) rRNA. It was shown long ago that the deleterious effects of these variants could remain dormant until an external stimulus triggered their pathogenicity. Yet, the link from the fidelity defect at the mito-ribosomal level to its phenotypic manifestation remained obscure. Recent work with fidelity-impaired mito-ribosomes, carrying error-prone and hyper-accurate mutations in mito-ribosomal proteins, have started to reveal the complexities of the phenotypic manifestation of mito-ribosomal fidelity defects, leading to a new understanding of mtDNA disease. While much needs to be done to arrive to a clear picture of how defects at the level of mito-ribosomal translation eventually result in the complex patterns of disease observed in patients, the current evidence indicates that altered mito-ribosome function, even at very low levels, may become highly pathogenic. The aims of this review are three-fold. First, we compare the molecular details associated with mito-ribosomal fidelity to those of general ribosomal fidelity. Second, we gather information on the cellular and organismal phenotypes associated with defective translational fidelity in order to provide the necessary grounds for an understanding of the phenotypic manifestation of defective mito-ribosomal fidelity. Finally, the results of recent experiments directly tackling mito-ribosomal fidelity are reviewed and future paths of investigation are discussed.
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Affiliation(s)
- Antón Vila-Sanjurjo
- Grupo GIBE, Departamento de Bioloxía e Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña (UDC), A Coruña, Spain
| | - Natalia Mallo
- Grupo GIBE, Departamento de Bioloxía e Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña (UDC), A Coruña, Spain
| | - John F Atkins
- Schools of Biochemistry and Microbiology, University College Cork, Cork, Ireland
| | - Joanna L Elson
- The Bioscience Institute, Newcastle University, Newcastle uponTyne, United Kingdom
- Human Metabolomics, North-West University, Potchefstroom, South Africa
| | - Paul M Smith
- Department of Paediatrics, Raigmore Hospital, Inverness, Scotland, United Kingdom
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Ferraz R, Coimbra S, Correia S, Canhoto J. RNA methyltransferases in plants: Breakthroughs in function and evolution. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 194:449-460. [PMID: 36502609 DOI: 10.1016/j.plaphy.2022.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/28/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Each day it is becoming increasingly difficult not to notice the completely new, fast growing, extremely intricate and challenging world of epitranscriptomics as the understanding of RNA methylation is expanding at a hasty rate. Writers (methyltransferases), erasers (demethylases) and readers (RNA-binding proteins) are responsible for adding, removing and recognising methyl groups on RNA, respectively. Several methyltransferases identified in plants are now being investigated and recent studies have shown a connection between RNA-methyltransferases (RNA-MTases) and stress and development processes. However, compared to their animal and bacteria counterparts, the understanding of RNA methyltransferases is still incipient, particularly those located in organelles. Comparative and systematic analyses allowed the tracing of the evolution of these enzymes suggesting the existence of several methyltransferases yet to be characterised. This review outlines the functions of plant nuclear and organellar RNA-MTases in plant development and stress responses and the comparative and evolutionary discoveries made on RNA-MTases across kingdoms.
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Affiliation(s)
- Ricardo Ferraz
- Centre for Functional Ecology, TERRA Associate Laboratory, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, Coimbra 3000-456, Portugal; LAQV Requimte, Sustainable Chemistry, University of Porto, Porto, Portugal.
| | - Sílvia Coimbra
- University of Porto, Faculty of Sciences, Portugal; LAQV Requimte, Sustainable Chemistry, University of Porto, Porto, Portugal.
| | - Sandra Correia
- Centre for Functional Ecology, TERRA Associate Laboratory, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, Coimbra 3000-456, Portugal.
| | - Jorge Canhoto
- Centre for Functional Ecology, TERRA Associate Laboratory, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, Coimbra 3000-456, Portugal.
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Zhang Z, Yang D, Zhou B, Luan Y, Yao Q, Liu Y, Yang S, Jia J, Xu Y, Bie X, Wang Y, Li Z, Li A, Zheng H, He Y. Decrease of MtDNA copy number affects mitochondrial function and involves in the pathological consequences of ischaemic stroke. J Cell Mol Med 2022; 26:4157-4168. [PMID: 35791521 PMCID: PMC9344826 DOI: 10.1111/jcmm.17262] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 02/05/2022] [Accepted: 02/10/2022] [Indexed: 11/28/2022] Open
Abstract
The mtDNA copy number can affect the function of mitochondria and play an important role in the development of diseases. However, there are few studies on the mechanism of mtDNA copy number variation and its effects in IS. The specific mechanism of mtDNA copy number variation is still unclear. In this study, mtDNA copy number of 101 IS patients and 101 normal controls were detected by qRT‐PCR, the effect of D‐loop variation on mtDNA copy number of IS patients was explored. Then, a TFAM gene KD‐OE PC12 cell model was constructed to explore the effect of mtDNA copy number variation on mitochondrial function. The results showed that the mtDNA copy number level of the IS group was significantly lower than that of the normal control group (p < 0.05). The relative expression of TFAM gene mRNA in the cells of the OGD/R treatment group was significantly lower than that of the control group (p < 0.05). In addition, after TFAM gene knockdown and over‐expression plasmids were transfected into HEK 293T cells, mtDNA copy number and ATP production level of Sh‐TFAM transfection group was significantly decreased (p < 0.05), while mtDNA copy number and ATP production level of OE‐TFAM transfected group were significantly higher than that of blank control group and OE‐ctrl negative control group (p < 0.01). Our study demonstrated that mitochondrial D‐loop mutation and TFAM gene dysfunction can cause the decrease of mtDNA copy number, thus affecting the mitochondrial metabolism and function of nerve cells, participating in the pathological damage mechanism of IS.
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Affiliation(s)
- Zhaojing Zhang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Dongzhi Yang
- School of Life Sciences, Zhengzhou University, Zhengzhou, China
| | - Baixue Zhou
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yingying Luan
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Qihui Yao
- Department of Pathology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Yang Liu
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Shangdong Yang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Jing Jia
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yan Xu
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Xiaoshuai Bie
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yuanli Wang
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Zhihao Li
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Aifan Li
- Department of Neurology, The First People's Hospital of Zhengzhou, Zhengzhou, China
| | - Hong Zheng
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Ying He
- Department of Medical Genetics & Cell Biology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
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Mitochondrial rRNA Methylation by Mettl15 Contributes to the Exercise and Learning Capability in Mice. Int J Mol Sci 2022; 23:ijms23116056. [PMID: 35682734 PMCID: PMC9181494 DOI: 10.3390/ijms23116056] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/22/2022] [Accepted: 05/26/2022] [Indexed: 02/01/2023] Open
Abstract
Mitochondrial translation is a unique relic of the symbiotic origin of the organelle. Alterations of its components cause a number of severe human diseases. Hereby we report a study of mice devoid of Mettl15 mitochondrial 12S rRNA methyltransferase, responsible for the formation of m4C839 residue (human numbering). Homozygous Mettl15−/− mice appeared to be viable in contrast to other mitochondrial rRNA methyltransferase knockouts reported earlier. The phenotype of Mettl15−/− mice is much milder than that of other mutants of mitochondrial translation apparatus. In agreement with the results obtained earlier for cell cultures with an inactivated Mettl15 gene, we observed accumulation of the RbfA factor, normally associated with the precursor of the 28S subunit, in the 55S mitochondrial ribosome fraction of knockout mice. A lack of Mettl15 leads to a lower blood glucose level after physical exercise relative to that of the wild-type mice. Mettl15−/− mice demonstrated suboptimal muscle performance and lower levels of Cox3 protein synthesized by mitoribosomes in the oxidative soleus muscles. Additionally, we detected decreased learning capabilities in the Mettl15−/− knockout mice in the tests with both positive and negative reinforcement. Such properties make Mettl15−/− knockout mice a suitable model for mild mitochondriopathies.
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[The role of chondrocyte mitochondrial biogenesis in the pathogenesis of osteoarthritis]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 2022; 36:242-248. [PMID: 35172413 PMCID: PMC8863531 DOI: 10.7507/1002-1892.202109091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
OBJECTIVE To summarize the role of chondrocytes mitochondrial biogenesis in the pathogenesis of osteoarthritis (OA), and analyze the applications in the treatment of OA. METHODS A review of recent literature was conducted to summarize the changes in mitochondrial biogenesis in the course of OA, the role of major signaling molecules in OA chondrocytes, and the prospects for OA therapeutic applications. RESULTS Recent studies reveales that mitochondria are significant energy metabolic centers in chondrocytes and its dysfunction has been considered as an essential mechanism in the pathogenesis of OA. Mitochondrial biogenesis is one of the key processes maintaining the normal quantity and function of mitochondria, and peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) is the central regulator of this process. A regulatory network of mitochondrial biogenesis with PGC-1α as the center, adenosine monophosphate-activated protein kinase, sirtuin1/3, and cyclic adenosine monophosphate response element-binding protein as the main upstream regulatory molecules, and nuclear respiratory factor 1, estrogen-related receptor α, and nuclear respiratory factor 2 as the main downstream regulatory molecules has been reported. However, the role of mitochondrial biogenesis in OA chondrocytes still needs further validation and in-depth exploration. It has been demonstrated that substances such as puerarin and omentin-1 can retard the development of OA by activating the damaged mitochondrial biogenesis in OA chondrocytes, which proves the potential to be used in the treatment OA. CONCLUSION Mitochondrial biogenesis in chondrocytes plays an important role in the pathogenesis of OA, and further exploring the related mechanisms is of great clinical significance.
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田 雨, 陈 正. [Progress in genetic susceptibility to aminoglycoside-induced deafness]. LIN CHUANG ER BI YAN HOU TOU JING WAI KE ZA ZHI = JOURNAL OF CLINICAL OTORHINOLARYNGOLOGY, HEAD, AND NECK SURGERY 2021; 35:375-379. [PMID: 33794642 PMCID: PMC10128447 DOI: 10.13201/j.issn.2096-7993.2021.04.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Indexed: 06/12/2023]
Abstract
Aminoglycoside antibiotics can cause irreversible hearing loss, but they are still widely used because of their low production cost and broad-spectrum effect on most infections. Although it has been studied for decades, the mechanism of aminoglycoside-induced deafness has not been fully elucidated. Since patients'individual susceptibility to aminoglycoside-ototoxicity varies considerably, it is necessary to identify high-risk patients. This review summarizes the genetic mutations linked to aminoglycoside-induced deafness, in order to provide reference for further prevention and treatment of aminoglycoside-induced deafness.
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Affiliation(s)
- 雨鑫 田
- 上海交通大学附属第六人民医院耳鼻咽喉头颈外科 上海交通大学耳鼻咽喉科研究所 上海市睡眠呼吸障碍疾病重点实验室(上海,200233)
| | - 正侬 陈
- 上海交通大学附属第六人民医院耳鼻咽喉头颈外科 上海交通大学耳鼻咽喉科研究所 上海市睡眠呼吸障碍疾病重点实验室(上海,200233)
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Ferrari A, Del'Olio S, Barrientos A. The Diseased Mitoribosome. FEBS Lett 2020; 595:1025-1061. [PMID: 33314036 DOI: 10.1002/1873-3468.14024] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/03/2020] [Accepted: 12/06/2020] [Indexed: 12/17/2022]
Abstract
Mitochondria control life and death in eukaryotic cells. Harboring a unique circular genome, a by-product of an ancient endosymbiotic event, mitochondria maintains a specialized and evolutionary divergent protein synthesis machinery, the mitoribosome. Mitoribosome biogenesis depends on elements encoded in both the mitochondrial genome (the RNA components) and the nuclear genome (all ribosomal proteins and assembly factors). Recent cryo-EM structures of mammalian mitoribosomes have illuminated their composition and provided hints regarding their assembly and elusive mitochondrial translation mechanisms. A growing body of literature involves the mitoribosome in inherited primary mitochondrial disorders. Mutations in genes encoding mitoribosomal RNAs, proteins, and assembly factors impede mitoribosome biogenesis, causing protein synthesis defects that lead to respiratory chain failure and mitochondrial disorders such as encephalo- and cardiomyopathy, deafness, neuropathy, and developmental delays. In this article, we review the current fundamental understanding of mitoribosome assembly and function, and the clinical landscape of mitochondrial disorders driven by mutations in mitoribosome components and assembly factors, to portray how basic and clinical studies combined help us better understand both mitochondrial biology and medicine.
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Affiliation(s)
- Alberto Ferrari
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA
| | - Samuel Del'Olio
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA.,Molecular and Cellular Pharmacology Graduate Program, University of Miami Miller School of Medicine, FL, USA
| | - Antoni Barrientos
- Department of Neurology, University of Miami Miller School of Medicine, FL, USA.,Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, FL, USA
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F C Lopes A. Mitochondrial metabolism and DNA methylation: a review of the interaction between two genomes. Clin Epigenetics 2020; 12:182. [PMID: 33228792 PMCID: PMC7684747 DOI: 10.1186/s13148-020-00976-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/10/2020] [Indexed: 02/06/2023] Open
Abstract
Mitochondria are controlled by the coordination of two genomes: the mitochondrial and the nuclear DNA. As such, variations in nuclear gene expression as a consequence of mutations and epigenetic modifications can affect mitochondrial functionality. Conversely, the opposite could also be true. However, the relationship between mitochondrial dysfunction and epigenetics, such as nuclear DNA methylation, remains largely unexplored.
Mitochondria function as central metabolic hubs controlling some of the main substrates involved in nuclear DNA methylation, via the one carbon metabolism, the tricarboxylic acid cycle and the methionine pathway. Here, we review key findings and highlight new areas of focus, with the ultimate goal of getting one step closer to understanding the genomic effects of mitochondrial dysfunction on nuclear epigenetic landscapes.
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Affiliation(s)
- Amanda F C Lopes
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK. .,Medical Research Council - Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK.
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10
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Sha W, Hu F, Bu S. Mitochondrial dysfunction and pancreatic islet β-cell failure (Review). Exp Ther Med 2020; 20:266. [PMID: 33199991 PMCID: PMC7664595 DOI: 10.3892/etm.2020.9396] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/17/2020] [Indexed: 02/07/2023] Open
Abstract
Pancreatic β-cells are the only source of insulin in humans. Mitochondria uses pyruvate to produce ATP as an intermediate link between glucose intake and insulin secretion in β-cells, in a process known as glucose-stimulated insulin secretion (GSIS). Previous studies have demonstrated that GSIS is negatively regulated by various factors in the mitochondria, including tRNALeu mutations, high p58 expression, reduced nicotinamide nucleotide transhydrogenase activity, abnormal levels of uncoupling proteins and reduced expression levels of transcription factors A, B1 and B2. Additionally, oxidative stress damages mitochondria and impairs antioxidant defense mechanisms, leading to the increased production of reactive oxygen species, which induces β-cell dysfunction. Inflammation in islets can also damage β-cell physiology. Inflammatory cytokines trigger the release of cytochrome c from the mitochondria via the NF-κB pathway. The present review examined the potential factors underlying mitochondrial dysfunction and their association with islet β-cell failure, which may offer novel insights regarding future strategies for the preservation of mitochondrial function and enhancement of antioxidant activity for individuals with diabetes mellitus.
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Affiliation(s)
- Wenxin Sha
- Diabetes Research Center, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Fei Hu
- Diabetes Research Center, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Shizhong Bu
- Diabetes Research Center, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
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11
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Gupta A, Shrivastava D, Shakya AK, Gupta K, Pratap JV, Habib S. PfKsgA1 functions as a transcription initiation factor and interacts with the N-terminal region of the mitochondrial RNA polymerase of Plasmodium falciparum. Int J Parasitol 2020; 51:23-37. [PMID: 32896572 DOI: 10.1016/j.ijpara.2020.07.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/13/2020] [Accepted: 07/16/2020] [Indexed: 10/23/2022]
Abstract
The small mitochondrial genome (mtDNA) of the malaria parasite is known to transcribe its genes polycistonically, although promoter element(s) have not yet been identified. An unusually large Plasmodium falciparum candidate mitochondrial phage-like RNA polymerase (PfmtRNAP) with an extended N-terminal region is encoded by the parasite nuclear genome. Using specific antibodies against the enzyme, we established that PfmtRNAP was targeted exclusively to the mitochondrion and interacted with mtDNA. Phylogenetic analysis showed that it is part of a separate apicomplexan clade. A search for PfmtRNAP-associated transcription initiation factors using sequence homology and in silico protein-protein interaction network analysis identified PfKsgA1. PfKsgA1 is a dual cytosol- and mitochondrion-targeted protein that functions as a small subunit rRNA dimethyltransferase in ribosome biogenesis. Chromatin immunoprecipitation showed that PfKsgA1 interacts with mtDNA, and in vivo crosslinking and pull-down experiments confirmed PfmtRNAP-PfKsgA1 interaction. The ability of PfKsgA1 to serve as a transcription initiation factor was demonstrated by complementation of yeast mitochondrial transcription factor Mtf1 function in Rpo41-driven in vitro transcription. Pull-down experiments using PfKsgA1 and PfmtRNAP domains indicated that the N-terminal region of PfmtRNAP interacts primarily with the PfKsgA1 C-terminal domain with some contacts being made with the linker and N-terminal domain of PfKsgA1. In the absence of full-length recombinant PfmtRNAP, solution structures of yeast mitochondrial RNA polymerase Rpo41 complexes with Mtf1 or PfKsgA1 were determined by small-angle X-ray scattering. Protein interaction interfaces thus identified matched with those reported earlier for Rpo41-Mtf1 interaction and overlaid with the PfmtRNAP-interfacing region identified experimentally for PfKsgA1. Our results indicate that in addition to a role in mitochondrial ribosome biogenesis, PfKsgA1 has an independent function as a transcription initiation factor for PfmtRNAP.
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Affiliation(s)
- Ankit Gupta
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Deepti Shrivastava
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow 226031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Anil Kumar Shakya
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Kirti Gupta
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - J V Pratap
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Saman Habib
- Division of Molecular and Structural Biology, CSIR-Central Drug Research Institute, Lucknow 226031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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12
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Zou M, Mu Y, Chai X, Ouyang M, Yu LJ, Zhang L, Meurer J, Chi W. The critical function of the plastid rRNA methyltransferase, CMAL, in ribosome biogenesis and plant development. Nucleic Acids Res 2020; 48:3195-3210. [PMID: 32095829 PMCID: PMC7102989 DOI: 10.1093/nar/gkaa129] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 02/12/2020] [Accepted: 02/18/2020] [Indexed: 12/12/2022] Open
Abstract
Methylation of nucleotides in ribosomal RNAs (rRNAs) is a ubiquitous feature that occurs in all living organisms. The formation of methylated nucleotides is performed by a variety of RNA-methyltransferases. Chloroplasts of plant cells result from an endosymbiotic event and possess their own genome and ribosomes. However, enzymes responsible for rRNA methylation and the function of modified nucleotides in chloroplasts remain to be determined. Here, we identified an rRNA methyltransferase, CMAL (Chloroplast MraW-Like), in the Arabidopsis chloroplast and investigated its function. CMAL is the Arabidopsis ortholog of bacterial MraW/ RsmH proteins and accounts to the N4-methylation of C1352 in chloroplast 16S rRNA, indicating that CMAL orthologs and this methyl-modification nucleotide is conserved between bacteria and the endosymbiont-derived eukaryotic organelle. The knockout of CMAL in Arabidopsis impairs the chloroplast ribosome accumulation and accordingly reduced the efficiency of mRNA translation. Interestingly, the loss of CMAL leads not only to defects in chloroplast function, but also to abnormal leaf and root development and overall plant morphology. Further investigation showed that CMAL is involved in the plant development probably by modulating auxin derived signaling pathways. This study uncovered the important role of 16S rRNA methylation mediated by CMAL in chloroplast ribosome biogenesis and plant development.
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Affiliation(s)
- Meijuan Zou
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ying Mu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xin Chai
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Ouyang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Long-Jiang Yu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Lixin Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Jörg Meurer
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University, Munich, D-82152 Planegg-Martinsried, Germany
| | - Wei Chi
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,University of Chinese Academy of Sciences, Beijing 100049, China
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13
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Pronsato L, Milanesi L, Vasconsuelo A. Testosterone induces up-regulation of mitochondrial gene expression in murine C2C12 skeletal muscle cells accompanied by an increase of nuclear respiratory factor-1 and its downstream effectors. Mol Cell Endocrinol 2020; 500:110631. [PMID: 31676390 DOI: 10.1016/j.mce.2019.110631] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 10/25/2019] [Accepted: 10/25/2019] [Indexed: 01/03/2023]
Abstract
The reduction in muscle mass and strength with age, sarcopenia, is a prevalent condition among the elderly, linked to skeletal muscle dysfunction and cell apoptosis. We demonstrated that testosterone protects against H2O2-induced apoptosis in C2C12 muscle cells. Here, we analyzed the effect of testosterone on mitochondrial gene expression in C2C12 skeletal muscle cells. We found that testosterone increases mRNA expression of genes encoded by mitochondrial DNA, such as NADPH dehydrogenase subunit 1 (ND1), subunit 4 (ND4), cytochrome b (CytB), cytochrome c oxidase subunit 1 (Cox1) and subunit 2 (Cox2) in C2C12. Additionally, the hormone induced the expression of the nuclear respiratory factors 1 and 2 (Nrf-1 and Nrf-2), the mitochondrial transcription factors A (Tfam) and B2 (TFB2M), and the optic atrophy 1 (OPA1). The simultaneous treatment with testosterone and the androgen receptor antagonist, Flutamide, reduced these effects. H2O2-oxidative stress induced treatment, significantly decreased mitochondrial gene expression. Computational analysis revealed that mitochondrial DNA contains specific sequences, which the androgen receptor could recognize and bind, probably taking place a direct regulation of mitochondrial transcription by the receptor. These findings indicate that androgen plays an important role in the regulation of mitochondrial transcription and biogenesis in skeletal muscle.
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Affiliation(s)
- Lucía Pronsato
- Instituto de Investigaciones Biológicas y Biomédicas del Sur (INBIOSUR-CONICET), 8000, Bahía Blanca, Argentina.
| | - Lorena Milanesi
- Instituto de Investigaciones Biológicas y Biomédicas del Sur (INBIOSUR-CONICET), 8000, Bahía Blanca, Argentina.
| | - Andrea Vasconsuelo
- Instituto de Investigaciones Biológicas y Biomédicas del Sur (INBIOSUR-CONICET), 8000, Bahía Blanca, Argentina
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14
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Lind AL, Lai YYY, Mostovoy Y, Holloway AK, Iannucci A, Mak ACY, Fondi M, Orlandini V, Eckalbar WL, Milan M, Rovatsos M, Kichigin IG, Makunin AI, Johnson Pokorná M, Altmanová M, Trifonov VA, Schijlen E, Kratochvíl L, Fani R, Velenský P, Rehák I, Patarnello T, Jessop TS, Hicks JW, Ryder OA, Mendelson JR, Ciofi C, Kwok PY, Pollard KS, Bruneau BG. Genome of the Komodo dragon reveals adaptations in the cardiovascular and chemosensory systems of monitor lizards. Nat Ecol Evol 2019; 3:1241-1252. [PMID: 31358948 PMCID: PMC6668926 DOI: 10.1038/s41559-019-0945-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 06/13/2019] [Indexed: 01/24/2023]
Abstract
Monitor lizards are unique among ectothermic reptiles in that they have high aerobic capacity and distinctive cardiovascular physiology resembling that of endothermic mammals. Here, we sequence the genome of the Komodo dragon Varanus komodoensis, the largest extant monitor lizard, and generate a high-resolution de novo chromosome-assigned genome assembly for V. komodoensis using a hybrid approach of long-range sequencing and single-molecule optical mapping. Comparing the genome of V. komodoensis with those of related species, we find evidence of positive selection in pathways related to energy metabolism, cardiovascular homoeostasis, and haemostasis. We also show species-specific expansions of a chemoreceptor gene family related to pheromone and kairomone sensing in V. komodoensis and other lizard lineages. Together, these evolutionary signatures of adaptation reveal the genetic underpinnings of the unique Komodo dragon sensory and cardiovascular systems, and suggest that selective pressure altered haemostasis genes to help Komodo dragons evade the anticoagulant effects of their own saliva. The Komodo dragon genome is an important resource for understanding the biology of monitor lizards and reptiles worldwide.
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Affiliation(s)
| | - Yvonne Y Y Lai
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
| | - Yulia Mostovoy
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
| | | | - Alessio Iannucci
- Department of Biology, University of Florence, Sesto Fiorentino, Italy
| | - Angel C Y Mak
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
| | - Marco Fondi
- Department of Biology, University of Florence, Sesto Fiorentino, Italy
| | - Valerio Orlandini
- Department of Biology, University of Florence, Sesto Fiorentino, Italy
| | - Walter L Eckalbar
- Institute for Human Genetics, University of California, San Francisco, CA, USA
| | - Massimo Milan
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Italy
| | - Michail Rovatsos
- Department of Ecology, Charles University, Prague, Czech Republic
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Liběchov, Czech Republic
| | - Ilya G Kichigin
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia
| | - Alex I Makunin
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia
| | - Martina Johnson Pokorná
- Department of Ecology, Charles University, Prague, Czech Republic
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Liběchov, Czech Republic
| | - Marie Altmanová
- Department of Ecology, Charles University, Prague, Czech Republic
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Liběchov, Czech Republic
| | | | - Elio Schijlen
- B.U. Bioscience, Wageningen University, Wageningen, The Netherlands
| | - Lukáš Kratochvíl
- Department of Ecology, Charles University, Prague, Czech Republic
| | - Renato Fani
- Department of Biology, University of Florence, Sesto Fiorentino, Italy
| | | | - Ivan Rehák
- Prague Zoological Garden, Prague, Czech Republic
| | - Tomaso Patarnello
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Italy
| | - Tim S Jessop
- Centre for Integrative Ecology, Deakin University, Waurn Ponds, Victoria, Australia
| | - James W Hicks
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, University of California, Irvine, CA, USA
| | - Oliver A Ryder
- Institute for Conservation Research, San Diego Zoo, Escondido, CA, USA
| | - Joseph R Mendelson
- Zoo Atlanta, Atlanta, GA, USA
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Claudio Ciofi
- Department of Biology, University of Florence, Sesto Fiorentino, Italy
| | - Pui-Yan Kwok
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
- Institute for Human Genetics, University of California, San Francisco, CA, USA
- Department of Dermatology, University of California, San Francisco, CA, USA
| | - Katherine S Pollard
- Gladstone Institutes, San Francisco, CA, USA.
- Institute for Human Genetics, University of California, San Francisco, CA, USA.
- Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA.
- Institute for Computational Health Sciences, University of California, San Francisco, CA, USA.
- Chan-Zuckerberg BioHub, San Francisco, CA, USA.
| | - Benoit G Bruneau
- Gladstone Institutes, San Francisco, CA, USA.
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA.
- Department of Pediatrics, University of California, San Francisco, CA, USA.
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15
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Bouda E, Stapon A, Garcia-Diaz M. Mechanisms of mammalian mitochondrial transcription. Protein Sci 2019; 28:1594-1605. [PMID: 31309618 DOI: 10.1002/pro.3688] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 01/06/2023]
Abstract
Numerous age-related human diseases have been associated with deficiencies in cellular energy production. Moreover, genetic alterations resulting in mitochondrial dysfunction are the cause of inheritable disorders commonly known as mitochondrial diseases. Many of these deficiencies have been directly or indirectly linked to deficits in mitochondrial gene expression. Transcription is an essential step in gene expression and elucidating the molecular mechanisms involved in this process is critical for understanding defects in energy production. For the past five decades, substantial efforts have been invested in the field of mitochondrial transcription. These efforts have led to the discovery of the main protein factors responsible for transcription as well as to a basic mechanistic understanding of the transcription process. They have also revealed various mechanisms of transcriptional regulation as well as the links that exist between the transcription process and downstream processes of RNA maturation. Here, we review the knowledge gathered in early mitochondrial transcription studies and focus on recent findings that shape our current understanding of mitochondrial transcription, posttranscriptional processing, as well as transcriptional regulation in mammalian systems.
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Affiliation(s)
- Emilie Bouda
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York
| | - Anthony Stapon
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York
| | - Miguel Garcia-Diaz
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York
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16
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Charmpilas N, Tavernarakis N. Mitochondrial maturation drives germline stem cell differentiation in Caenorhabditis elegans. Cell Death Differ 2019; 27:601-617. [PMID: 31217501 PMCID: PMC7206027 DOI: 10.1038/s41418-019-0375-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 05/27/2019] [Accepted: 06/03/2019] [Indexed: 01/07/2023] Open
Abstract
The C. elegans germline recapitulates mammalian stem cell niches and provides an effective platform for investigating key aspects of stem cell biology. However, the molecular and physiological requirements for germline stem cell homeostasis remain largely elusive. Here, we report that mitochondrial biogenesis and function are crucial for germline stem cell identity. We show that general transcription activity in germline mitochondria is highly compartmentalized, and determines mitochondrial maturation. RPOM-1, the mitochondrial RNA polymerase, is differentially expressed as germ nuclei progress from the distal to the proximal gonad arm to form oocytes. Mitochondria undergo changes from globular to tubular morphology and become polarized, as they approach the proximal gonad arm. Notably, this mitochondrial maturation trajectory is evolutionarily conserved. We find that a similar transition and temporal mitochondrial RNA polymerase expression profile characterizes differentiation of mammalian stem cells. In C. elegans, ATP, and ROS production increases sharply during maturation. Impaired mitochondrial bioenergetics causes gonad syncytium tumor formation by disrupting the balance between mitosis and differentiation to oocytes, which results in a marked reduction of fecundity. Consequently, compensatory apoptosis is induced in the germline. Sperm-derived signals promote mitochondrial maturation and proper germ cell differentiation via the MEK/ERK kinase pathway. Germ cell fate decisions are determined by a crosstalk between Insulin/IGF-1 and TGF-β signaling, mitochondria and protein synthesis. Our findings demonstrate that mitochondrial transcription activity determines a shift in mitochondrial bioenergetics, which in turn regulates germline stem cell survival and differentiation. Perturbation of mitochondrial transcription hinders proper germ cell differentiation and causes germline tumor development.
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Affiliation(s)
- Nikolaos Charmpilas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece.,Department of Biology, University of Crete, Heraklion, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece. .,Department of Basic Sciences, School of Medicine, University of Crete, 70013, Heraklion, Crete, Greece.
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17
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Sergiev PV, Aleksashin NA, Chugunova AA, Polikanov YS, Dontsova OA. Structural and evolutionary insights into ribosomal RNA methylation. Nat Chem Biol 2019; 14:226-235. [PMID: 29443970 DOI: 10.1038/nchembio.2569] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 01/02/2018] [Indexed: 01/24/2023]
Abstract
Methylation of nucleotides in ribosomal RNAs (rRNAs) is a ubiquitous feature that occurs in all living organisms. Identification of all enzymes responsible for rRNA methylation, as well as mapping of all modified rRNA residues, is now complete for a number of model species, such as Escherichia coli and Saccharomyces cerevisiae. Recent high-resolution structures of bacterial ribosomes provided the first direct visualization of methylated nucleotides. The structures of ribosomes from various organisms and organelles have also lately become available, enabling comparative structure-based analysis of rRNA methylation sites in various taxonomic groups. In addition to the conserved core of modified residues in ribosomes from the majority of studied organisms, structural analysis points to the functional roles of some of the rRNA methylations, which are discussed in this Review in an evolutionary context.
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Affiliation(s)
- Petr V Sergiev
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region, Russia.,Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia.,A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Nikolay A Aleksashin
- Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Anastasia A Chugunova
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region, Russia.,Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia
| | - Yury S Polikanov
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Olga A Dontsova
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow Region, Russia.,Department of Chemistry, Lomonosov Moscow State University, Moscow, Russia.,A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
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18
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Yambire KF, Fernandez-Mosquera L, Steinfeld R, Mühle C, Ikonen E, Milosevic I, Raimundo N. Mitochondrial biogenesis is transcriptionally repressed in lysosomal lipid storage diseases. eLife 2019; 8:e39598. [PMID: 30775969 PMCID: PMC6379092 DOI: 10.7554/elife.39598] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 02/11/2019] [Indexed: 12/24/2022] Open
Abstract
Perturbations in mitochondrial function and homeostasis are pervasive in lysosomal storage diseases, but the underlying mechanisms remain unknown. Here, we report a transcriptional program that represses mitochondrial biogenesis and function in lysosomal storage diseases Niemann-Pick type C (NPC) and acid sphingomyelinase deficiency (ASM), in patient cells and mouse tissues. This mechanism is mediated by the transcription factors KLF2 and ETV1, which are both induced in NPC and ASM patient cells. Mitochondrial biogenesis and function defects in these cells are rescued by the silencing of KLF2 or ETV1. Increased ETV1 expression is regulated by KLF2, while the increase of KLF2 protein levels in NPC and ASM stems from impaired signaling downstream sphingosine-1-phosphate receptor 1 (S1PR1), which normally represses KLF2. In patient cells, S1PR1 is barely detectable at the plasma membrane and thus unable to repress KLF2. This manuscript provides a mechanistic pathway for the prevalent mitochondrial defects in lysosomal storage diseases. Editorial note This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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Affiliation(s)
- King Faisal Yambire
- Institute of Cellular BiochemistryUniversity Medical Center GoettingenGoettingenGermany
- International Max-Planck Research School in NeuroscienceGoettingenGermany
- European Neuroscience Institute GoettingenUniversity Medical Center GoettingenGoettingenGermany
| | | | - Robert Steinfeld
- Klinik für Kinder- und JugendmedizinUniversity Medical Center GoettingenGoettingenGermany
| | - Christiane Mühle
- Department of Psychiatry and PsychotherapyFriedrich-Alexander University Erlangen-Nürnberg (FAU)ErlangenGermany
| | - Elina Ikonen
- Department of Anatomy, Faculty of MedicineUniversity of Helsinki, Biomedicum HelsinkiHelsinkiFinland
| | - Ira Milosevic
- European Neuroscience Institute GoettingenUniversity Medical Center GoettingenGoettingenGermany
| | - Nuno Raimundo
- Institute of Cellular BiochemistryUniversity Medical Center GoettingenGoettingenGermany
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19
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Zurita Rendón O, Shoubridge EA. LONP1 Is Required for Maturation of a Subset of Mitochondrial Proteins, and Its Loss Elicits an Integrated Stress Response. Mol Cell Biol 2018; 38:e00412-17. [PMID: 30061372 PMCID: PMC6168981 DOI: 10.1128/mcb.00412-17] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 08/16/2017] [Accepted: 07/12/2018] [Indexed: 01/04/2023] Open
Abstract
LONP1, an AAA+ mitochondrial protease, is implicated in protein quality control, but its precise role in this process remains poorly understood. In this study, we have investigated the role of human LONP1 in mitochondrial proteostasis and gene expression. Depletion of LONP1 resulted in partial loss of mitochondrial DNA (mtDNA) and a complete suppression of mitochondrial translation associated with impaired ribosome biogenesis. The levels of a distinct subset of mitochondrial matrix proteins (SSBP1, MTERFD3, FASTKD2, and CLPX) increased in the presence of a catalytically dead form of LONP1, suggesting that they are bona fide LONP1 substrates. Unexpectedly, the unprocessed forms of the same proteins also accumulated in an insoluble protein fraction. This subset of unprocessed matrix proteins (but not their mature forms) accumulated following depletion of the mitochondrial processing peptidase MPP, though all other MPP substrates investigated were processed normally. Prolonged depletion of LONP1 produced massive matrix protein aggregates, robustly activated the integrated stress response (ISR) pathway, and resulted in stabilization of PINK1, a mitophagy marker. These results demonstrate that LONP1 and MPPαβ are together required for the maturation of a subset of LONP1 client proteins and that LONP1 activity is essential for the maintenance of mitochondrial proteostasis and gene expression.
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Affiliation(s)
- Olga Zurita Rendón
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Eric A Shoubridge
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
- Department of Human Genetics, McGill University, Montreal, QC, Canada
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20
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Abstract
Sensorineural hearing impairment is the most common sensory disorder and a major health and socio-economic issue in industrialized countries. It is primarily due to the degeneration of mechanosensory hair cells and spiral ganglion neurons in the cochlea via complex pathophysiological mechanisms. These occur following acute and/or chronic exposure to harmful extrinsic (e.g., ototoxic drugs, noise...) and intrinsic (e.g., aging, genetic) causative factors. No clinical therapies currently exist to rescue the dying sensorineural cells or regenerate these cells once lost. Recent studies have, however, provided renewed hope, with insights into the therapeutic targets allowing the prevention and treatment of ototoxic drug- and noise-induced, age-related hearing loss as well as cochlear cell degeneration. Moreover, genetic routes involving the replacement or corrective editing of mutant sequences or defected genes are showing promise, as are cell-replacement therapies to repair damaged cells for the future restoration of hearing in deaf people. This review begins by recapitulating our current understanding of the molecular pathways that underlie cochlear sensorineural damage, as well as the survival signaling pathways that can provide endogenous protection and tissue rescue. It then guides the reader through to the recent discoveries in pharmacological, gene and cell therapy research towards hearing protection and restoration as well as their potential clinical application.
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Affiliation(s)
- Jing Wang
- INSERM UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; and University of Montpellier, Montpellier, France
| | - Jean-Luc Puel
- INSERM UMR 1051, Institute for Neurosciences of Montpellier, Montpellier, France; and University of Montpellier, Montpellier, France
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21
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Gupta K, Gupta A, Habib S. Characterization of a Plasmodium falciparum rRNA methyltransferase. Mol Biochem Parasitol 2018; 223:13-18. [DOI: 10.1016/j.molbiopara.2018.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/12/2018] [Accepted: 06/12/2018] [Indexed: 12/29/2022]
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22
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High throughput screening of mitochondrial bioenergetics in human differentiated myotubes identifies novel enhancers of muscle performance in aged mice. Sci Rep 2018; 8:9408. [PMID: 29925868 PMCID: PMC6010423 DOI: 10.1038/s41598-018-27614-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 05/31/2018] [Indexed: 01/01/2023] Open
Abstract
Mitochondrial dysfunction is increasingly recognized as a contributor to age-related muscle loss and functional impairment. Therefore, we developed a high throughput screening strategy that enabled the identification of compounds boosting mitochondrial energy production in a human skeletal muscle cell model. Screening of 7949 pure natural products revealed 22 molecules that significantly increased oxygen consumption and ATP levels in myotubes. One of the most potent compounds was the flavanone hesperetin. Hesperetin (10 µM) increased intracellular ATP by 33% and mitochondrial spare capacity by 25%. Furthermore, the compound reduced oxidative stress in primary myotubes as well as muscle tissue in vivo. In aged mice administration of hesperetin (50 mg/kg/d) completely reverted the age-related decrease of muscle fiber size and improved running performance of treated animals. These results provide a novel screening platform for the discovery of drugs that can improve skeletal muscle function in patients suffering from sarcopenia or other disorders associated with mitochondrial dysfunction.
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23
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Abstract
Mitochondrial dysfunction underlines a multitude of pathologies; however, studies are scarce that rescue the mitochondria for cellular resuscitation. Exploration into the protective role of mitochondrial transcription factor A (TFAM) and its mitochondrial functions respective to cardiomyocyte death are in need of further investigation. TFAM is a gene regulator that acts to mitigate calcium mishandling and ROS production by wrapping around mitochondrial DNA (mtDNA) complexes. TFAM's regulatory functions over serca2a, NFAT, and Lon protease contribute to cardiomyocyte stability. Calcium- and ROS-dependent proteases, calpains, and matrix metalloproteinases (MMPs) are abundantly found upregulated in the failing heart. TFAM's regulatory role over ROS production and calcium mishandling leads to further investigation into the cardioprotective role of exogenous TFAM. In an effort to restabilize physiological and contractile activity of cardiomyocytes in HF models, we propose that TFAM-packed exosomes (TFAM-PE) will act therapeutically by mitigating mitochondrial dysfunction. Notably, this is the first mention of exosomal delivery of transcription factors in the literature. Here we elucidate the role of TFAM in mitochondrial rescue and focus on its therapeutic potential.
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Affiliation(s)
- George H Kunkel
- Department of Physiology and Biophysics, Health Sciences Centre, 1216, School of Medicine, University of Louisville, 500, South Preston Street, Louisville, KY, 40202, USA
| | - Pankaj Chaturvedi
- Department of Physiology and Biophysics, Health Sciences Centre, 1216, School of Medicine, University of Louisville, 500, South Preston Street, Louisville, KY, 40202, USA.
| | - Suresh C Tyagi
- Department of Physiology and Biophysics, Health Sciences Centre, 1216, School of Medicine, University of Louisville, 500, South Preston Street, Louisville, KY, 40202, USA
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25
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Kuszak AJ, Espey MG, Falk MJ, Holmbeck MA, Manfredi G, Shadel GS, Vernon HJ, Zolkipli-Cunningham Z. Nutritional Interventions for Mitochondrial OXPHOS Deficiencies: Mechanisms and Model Systems. ANNUAL REVIEW OF PATHOLOGY 2018; 13:163-191. [PMID: 29099651 PMCID: PMC5911915 DOI: 10.1146/annurev-pathol-020117-043644] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Multisystem metabolic disorders caused by defects in oxidative phosphorylation (OXPHOS) are severe, often lethal, conditions. Inborn errors of OXPHOS function are termed primary mitochondrial disorders (PMDs), and the use of nutritional interventions is routine in their supportive management. However, detailed mechanistic understanding and evidence for efficacy and safety of these interventions are limited. Preclinical cellular and animal model systems are important tools to investigate PMD metabolic mechanisms and therapeutic strategies. This review assesses the mechanistic rationale and experimental evidence for nutritional interventions commonly used in PMDs, including micronutrients, metabolic agents, signaling modifiers, and dietary regulation, while highlighting important knowledge gaps and impediments for randomized controlled trials. Cellular and animal model systems that recapitulate mutations and clinical manifestations of specific PMDs are evaluated for their potential in determining pathological mechanisms, elucidating therapeutic health outcomes, and investigating the value of nutritional interventions for mitochondrial disease conditions.
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Affiliation(s)
- Adam J Kuszak
- Office of Dietary Supplements, National Institutes of Health, Bethesda, Maryland 20852, USA;
| | - Michael Graham Espey
- Division of Cancer Biology, National Cancer Institute, Rockville, Maryland 20850, USA;
| | - Marni J Falk
- Department of Pediatrics, Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA;
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Marissa A Holmbeck
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut 06510-8023, USA;
| | - Giovanni Manfredi
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA;
| | - Gerald S Shadel
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut 06510-8023, USA;
- Department of Genetics, Yale School of Medicine, New Haven, Connecticut 06520-8023, USA;
| | - Hilary J Vernon
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA;
| | - Zarazuela Zolkipli-Cunningham
- Department of Pediatrics, Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA;
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Chen X, Sun YZ, Liu H, Zhang L, Li JQ, Meng J. RNA methylation and diseases: experimental results, databases, Web servers and computational models. Brief Bioinform 2017; 20:896-917. [DOI: 10.1093/bib/bbx142] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 09/12/2017] [Indexed: 12/15/2022] Open
Affiliation(s)
- Xing Chen
- School of Information and Control Engineering, China University of Mining and Technology, Xuzhou, China
| | - Ya-Zhou Sun
- College of Computer Science and Software Engineering, Shenzhen University, Shenzhen, China
| | - Hui Liu
- School of Information and Control Engineering, China University of Mining and Technology, Xuzhou, China
| | - Lin Zhang
- School of Information and Control Engineering, China University of Mining and Technology, Xuzhou, China
| | - Jian-Qiang Li
- College of Computer Science and Software Engineering, Shenzhen University, Shenzhen, China
| | - Jia Meng
- Department of Biological Sciences, Xi’an Jiaotong-Liverpool University
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27
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The human RNA-binding protein RBFA promotes the maturation of the mitochondrial ribosome. Biochem J 2017; 474:2145-2158. [PMID: 28512204 PMCID: PMC5468982 DOI: 10.1042/bcj20170256] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/09/2017] [Accepted: 05/15/2017] [Indexed: 11/17/2022]
Abstract
Accurate assembly and maturation of human mitochondrial ribosomes is essential for synthesis of the 13 polypeptides encoded by the mitochondrial genome. This process requires the correct integration of 80 proteins, 1 mt (mitochondrial)-tRNA and 2 mt-rRNA species, the latter being post-transcriptionally modified at many sites. Here, we report that human ribosome-binding factor A (RBFA) is a mitochondrial RNA-binding protein that exerts crucial roles in mitoribosome biogenesis. Unlike its bacterial orthologue, RBFA associates mainly with helices 44 and 45 of the 12S rRNA in the mitoribosomal small subunit to promote dimethylation of two highly conserved consecutive adenines. Characterization of RBFA-depleted cells indicates that this dimethylation is not a prerequisite for assembly of the small ribosomal subunit. However, the RBFA-facilitated modification is necessary for completing mt-rRNA maturation and regulating association of the small and large subunits to form a functional monosome implicating RBFA in the quality control of mitoribosome formation.
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Schenkel LC, Kernohan KD, McBride A, Reina D, Hodge A, Ainsworth PJ, Rodenhiser DI, Pare G, Bérubé NG, Skinner C, Boycott KM, Schwartz C, Sadikovic B. Identification of epigenetic signature associated with alpha thalassemia/mental retardation X-linked syndrome. Epigenetics Chromatin 2017; 10:10. [PMID: 28293299 PMCID: PMC5345252 DOI: 10.1186/s13072-017-0118-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/01/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Alpha thalassemia/mental retardation X-linked syndrome (ATR-X) is caused by a mutation at the chromatin regulator gene ATRX. The mechanisms involved in the ATR-X pathology are not completely understood, but may involve epigenetic modifications. ATRX has been linked to the regulation of histone H3 and DNA methylation, while mutations in the ATRX gene may lead to the downstream epigenetic and transcriptional effects. Elucidating the underlying epigenetic mechanisms altered in ATR-X will provide a better understanding about the pathobiology of this disease, as well as provide novel diagnostic biomarkers. RESULTS We performed genome-wide DNA methylation assessment of the peripheral blood samples from 18 patients with ATR-X and compared it to 210 controls. We demonstrated the evidence of a unique and highly specific DNA methylation "epi-signature" in the peripheral blood of ATRX patients, which was corroborated by targeted bisulfite sequencing experiments. Although genomically represented, differentially methylated regions showed evidence of preferential clustering in pericentromeric and telometric chromosomal regions, areas where ATRX has multiple functions related to maintenance of heterochromatin and genomic integrity. CONCLUSION Most significant methylation changes in the 14 genomic loci provide a unique epigenetic signature for this syndrome that may be used as a highly sensitive and specific diagnostic biomarker to support the diagnosis of ATR-X, particularly in patients with phenotypic complexity and in patients with ATRX gene sequence variants of unknown significance.
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Affiliation(s)
- Laila C Schenkel
- Department of Pathology and Lab Medicine, Western University, London, ON Canada
| | - Kristin D Kernohan
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON Canada
| | - Arran McBride
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON Canada
| | - Ditta Reina
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON Canada.,Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON Canada
| | - Amanda Hodge
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON Canada.,Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON Canada
| | - Peter J Ainsworth
- Department of Pathology and Lab Medicine, Western University, London, ON Canada.,Molecular Genetics Laboratory, Victoria Hospital, London Health Sciences Center, 800 Commissioner's Road E, B10-104, London, ON N6A 5W9 Canada.,Department of Paediatrics, Western University, London, ON Canada.,Department of Biochemistry, Western University, London, ON Canada.,Department of Oncology, Western University, London, ON Canada.,Children's Health Research Institute, London, ON Canada
| | - David I Rodenhiser
- Department of Paediatrics, Western University, London, ON Canada.,Department of Biochemistry, Western University, London, ON Canada.,Department of Oncology, Western University, London, ON Canada.,Children's Health Research Institute, London, ON Canada
| | - Guillaume Pare
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON Canada.,Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON Canada
| | - Nathalie G Bérubé
- Department of Paediatrics, Western University, London, ON Canada.,Department of Biochemistry, Western University, London, ON Canada.,Department of Oncology, Western University, London, ON Canada.,Children's Health Research Institute, London, ON Canada
| | - Cindy Skinner
- Center for Molecular Studies, J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, SC USA
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON Canada
| | - Charles Schwartz
- Center for Molecular Studies, J.C. Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, SC USA
| | - Bekim Sadikovic
- Department of Pathology and Lab Medicine, Western University, London, ON Canada.,Molecular Genetics Laboratory, Victoria Hospital, London Health Sciences Center, 800 Commissioner's Road E, B10-104, London, ON N6A 5W9 Canada.,Children's Health Research Institute, London, ON Canada
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29
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Bacalini MG, D'Aquila P, Marasco E, Nardini C, Montesanto A, Franceschi C, Passarino G, Garagnani P, Bellizzi D. The methylation of nuclear and mitochondrial DNA in ageing phenotypes and longevity. Mech Ageing Dev 2017; 165:156-161. [PMID: 28115210 DOI: 10.1016/j.mad.2017.01.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 11/29/2016] [Accepted: 01/16/2017] [Indexed: 12/28/2022]
Abstract
An increasing body of data is progressively indicating that the comprehension of the epigenetic landscape, actively integrated with the genetic elements, is crucial to delineate the molecular basis of the inter-individual complexity of ageing process. Indeed, it has emerged that DNA methylation changes occur during ageing, consisting mainly in a progressive process of genome demethylation, in a hypermethylation of gene-specific CpG dinucleotides, as well as in an inter-individual divergence of the epigenome due to stochastic events and environmental exposures throughout life, namely as epigenetic drift. Additionally, it has also come to light an implication of the mitochondrial genome in the regulation of the intracellular epigenetic landscape, as demonstrated by the being itself object of epigenetic modifications. An overview of DNA methylation changes occurring during ageing process at both nuclear and mitochondrial level will be described in this review, also taking into account the recent and promising data available on the 5-hydroxymethylcytosine.
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Affiliation(s)
- Maria Giulia Bacalini
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Via Altura 1/8, 40139 Bologna, Italy
| | - Patrizia D'Aquila
- Department of Biology, Ecology and Earth Sciences, University of Calabria, 87036 Rende, Italy
| | - Elena Marasco
- Department of Experimental, Diagnostic and Specialty Medicine, Alma Mater Studiorum, University of Bologna, 40138 Bologna, Italy
| | | | - Alberto Montesanto
- Department of Biology, Ecology and Earth Sciences, University of Calabria, 87036 Rende, Italy
| | - Claudio Franceschi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Via Altura 1/8, 40139 Bologna, Italy
| | - Giuseppe Passarino
- Department of Biology, Ecology and Earth Sciences, University of Calabria, 87036 Rende, Italy
| | - Paolo Garagnani
- Department of Experimental, Diagnostic and Specialty Medicine, Alma Mater Studiorum, University of Bologna, 40138 Bologna, Italy; Applied Biomedical Research Center, S.Orsola-Malpighi Polyclinic, 40138 Bologna, Italy; Interdepartmental Center "L. Galvani", Alma Mater Studiorum, University of Bologna, 40126 Bologna, Italy.
| | - Dina Bellizzi
- Department of Biology, Ecology and Earth Sciences, University of Calabria, 87036 Rende, Italy.
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30
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Shokolenko IN, Alexeyev MF. Mitochondrial transcription in mammalian cells. Front Biosci (Landmark Ed) 2017; 22:835-853. [PMID: 27814650 DOI: 10.2741/4520] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
As a consequence of recent discoveries of intimate involvement of mitochondria with key cellular processes, there has been a resurgence of interest in all aspects of mitochondrial biology, including the intricate mechanisms of mitochondrial DNA maintenance and expression. Despite four decades of research, there remains a lot to be learned about the processes that enable transcription of genetic information from mitochondrial DNA to RNA, as well as their regulation. These processes are vitally important, as evidenced by the lethality of inactivating the central components of mitochondrial transcription machinery. Here, we review the current understanding of mitochondrial transcription and its regulation in mammalian cells. We also discuss key theories in the field and highlight controversial subjects and future directions as we see them.
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Affiliation(s)
- Inna N Shokolenko
- University of South Alabama, Patt Capps Covey College of Allied Health Professions, Biomedical Sciences Department, 5721 USA Drive N, HAHN 4021, Mobile, AL 36688-0002, USA
| | - Mikhail F Alexeyev
- Department of Physiology and Cell Biology, University of South Alabama, 5851 USA Dr. North, MSB3074, Mobile, AL 36688, USA,
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31
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O’Sullivan ME, Perez A, Lin R, Sajjadi A, Ricci AJ, Cheng AG. Towards the Prevention of Aminoglycoside-Related Hearing Loss. Front Cell Neurosci 2017; 11:325. [PMID: 29093664 PMCID: PMC5651232 DOI: 10.3389/fncel.2017.00325] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 09/30/2017] [Indexed: 01/08/2023] Open
Abstract
Aminoglycosides are potent antibiotics deployed worldwide despite their known side-effect of sensorineural hearing loss. The main etiology of this sensory deficit is death of inner ear sensory hair cells selectively triggered by aminoglycosides. For decades, research has sought to unravel the molecular events mediating sensory cell demise, emphasizing the roles of reactive oxygen species and their potentials as therapeutic targets. Studies in recent years have revealed candidate transport pathways including the mechanotransducer channel for drug entry into sensory cells. Once inside sensory cells, intracellular targets of aminoglycosides, such as the mitochondrial ribosomes, are beginning to be elucidated. Based on these results, less ototoxic aminoglycoside analogs are being generated and may serve as alternate antimicrobial agents. In this article, we review the latest findings on mechanisms of aminoglycoside entry into hair cells, their intracellular actions and potential therapeutic targets for preventing aminoglycoside ototoxicity.
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Affiliation(s)
- Mary E. O’Sullivan
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
| | - Adela Perez
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
| | - Randy Lin
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
| | - Autefeh Sajjadi
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
| | - Anthony J. Ricci
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, United States
- *Correspondence: Anthony J. Ricci Alan G. Cheng
| | - Alan G. Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
- *Correspondence: Anthony J. Ricci Alan G. Cheng
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32
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Mazunin IO, Levitskii SA, Patrushev MV, Kamenski PA. Mitochondrial Matrix Processes. BIOCHEMISTRY (MOSCOW) 2016; 80:1418-28. [PMID: 26615433 DOI: 10.1134/s0006297915110036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Mitochondria possess their own genome that, despite its small size, is critically important for their functioning, as it encodes several dozens of RNAs and proteins. All biochemical processes typical for bacterial and nuclear DNA are described in mitochondrial matrix: replication, repair, recombination, and transcription. Commonly, their mechanisms are similar to those found in bacteria, but they are characterized by several unique features. In this review, we provide an overall description of mitochondrial matrix processes paying special attention to the typical features of such mechanisms.
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Affiliation(s)
- I O Mazunin
- Immanuil Kant Baltic Federal University, Institute of Chemistry and Biology, Kaliningrad, 236038, Russia.
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McKay SE, Yan W, Nouws J, Thormann MJ, Raimundo N, Khan A, Santos-Sacchi J, Song L, Shadel GS. Auditory Pathology in a Transgenic mtTFB1 Mouse Model of Mitochondrial Deafness. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:3132-40. [PMID: 26552864 DOI: 10.1016/j.ajpath.2015.08.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 07/31/2015] [Accepted: 08/14/2015] [Indexed: 12/13/2022]
Abstract
The A1555G mutation in the 12S rRNA gene of human mitochondrial DNA causes maternally inherited, nonsyndromic deafness, an extreme case of tissue-specific mitochondrial pathology. A transgenic mouse strain that robustly overexpresses the mitochondrial 12S ribosomal RNA methyltransferase TFB1M (Tg-mtTFB1 mice) exhibits progressive hearing loss that we proposed models aspects of A1555G-related pathology in humans. Although our previous studies of Tg-mtTFB1 mice implicated apoptosis in the spiral ganglion and stria vascularis because of mitochondrial reactive oxygen species-mediated activation of AMP kinase (AMPK) and the nuclear transcription factor E2F1, detailed auditory pathology was not delineated. Herein, we show that Tg-mtTFB1 mice have reduced endocochlear potential, indicative of significant stria vascularis dysfunction, but without obvious signs of strial atrophy. We also observed decreased auditory brainstem response peak 1 amplitude and prolonged wave I latency, consistent with apoptosis of spiral ganglion neurons. Although no major loss of hair cells was observed, there was a mild impairment of voltage-dependent electromotility of outer hair cells. On the basis of these results, we propose that these events conspire to produce the progressive hearing loss phenotype in Tg-mtTFB1 mice. Finally, genetically reducing AMPK α1 rescues hearing loss in Tg-mtTFB1 mice, confirming that aberrant up-regulation of AMPK signaling promotes the observed auditory pathology. The relevance of these findings to human A1555G patients and the potential therapeutic value of reducing AMPK activity are discussed.
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Affiliation(s)
- Sharen E McKay
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut; Department of Psychology, University of Bridgeport, Bridgeport, Connecticut
| | - Wayne Yan
- Department of Surgery, Yale School of Medicine, New Haven, Connecticut
| | - Jessica Nouws
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut
| | | | - Nuno Raimundo
- Institute of Cell Biology, University Medical Center Göettingen, Göttingen, Germany
| | - Abdul Khan
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut
| | - Joseph Santos-Sacchi
- Department of Surgery, Yale School of Medicine, New Haven, Connecticut; Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut; Department of Neurobiology, Yale School of Medicine, New Haven, Connecticut.
| | - Lei Song
- Department of Surgery, Yale School of Medicine, New Haven, Connecticut.
| | - Gerald S Shadel
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut; Department of Genetics, Yale School of Medicine, New Haven, Connecticut.
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Lee S, Rose S, Metodiev MD, Becker L, Vernaleken A, Klopstock T, Gailus-Durner V, Fuchs H, Hrabě De Angelis M, Douthwaite S, Larsson NG. Overexpression of the mitochondrial methyltransferase TFB1M in the mouse does not impact mitoribosomal methylation status or hearing. Hum Mol Genet 2015; 24:7286-94. [PMID: 26464487 PMCID: PMC4664167 DOI: 10.1093/hmg/ddv427] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 10/05/2015] [Indexed: 12/30/2022] Open
Abstract
Mitochondrial dysfunction is a well-established cause of sensorineural deafness, but the pathophysiological events are poorly understood. Non-syndromic deafness and predisposition to aminoglycoside-induced deafness can be caused by specific mutations in the 12S rRNA gene of mtDNA and are thus maternally inherited traits. The pathophysiology induced by mtDNA mutations has traditionally been attributed to deficient oxidative phosphorylation, which causes energy crisis with functional impairment of multiple cellular processes. In contrast, it was recently reported that signaling induced by ‘hypermethylation’ of two conserved adenosines of 12S rRNA in the mitoribosome is of key pathophysiological importance in sensorineural deafness. In support for this concept, it was reported that overexpression of the essential mitochondrial methyltransferase TFB1M in the mouse was sufficient to induce mitoribosomal hypermethylation and deafness. At variance with this model, we show here that 12S rRNA is near fully methylated in vivo in the mouse and thus cannot be further methylated to any significant extent. Furthermore, bacterial artificial chromosome transgenic mice overexpressing TFB1M have no increase of 12S rRNA methylation levels and hear normally. We thus conclude that therapies directed against mitoribosomal methylation are unlikely to be beneficial to patients with sensorineural hearing loss or other types of mitochondrial disease.
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Affiliation(s)
- Seungmin Lee
- Department of Laboratory Medicine, Karolinska Institutet, Retzius väg 8, 171 77 Stockholm, Sweden
| | - Simon Rose
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Metodi D Metodiev
- INSERM U1163, Université Paris Descartes-Sorbonne Paris Cité, Institut Imagine, 75015 Paris, France
| | - Lore Becker
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, 85764 Munich/Neuherberg, Germany, Department of Neurology, Friedrich-Baur-Institute, Ludwig-Maximilians-University, Munich, Germany
| | - Alexandra Vernaleken
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, 85764 Munich/Neuherberg, Germany, Department of Neurology, Friedrich-Baur-Institute, Ludwig-Maximilians-University, Munich, Germany, German Center for Vertigo and Balance Disorders, Munich, Germany
| | - Thomas Klopstock
- Department of Neurology, Friedrich-Baur-Institute, Ludwig-Maximilians-University, Munich, Germany, German Center for Vertigo and Balance Disorders, Munich, Germany
| | - Valerie Gailus-Durner
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, 85764 Munich/Neuherberg, Germany
| | - Helmut Fuchs
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, 85764 Munich/Neuherberg, Germany
| | - Martin Hrabě De Angelis
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, 85764 Munich/Neuherberg, Germany, German Center for Vertigo and Balance Disorders, Munich, Germany, Chair of Experimental Genetics, Center of Life and Food Sciences Weihenstephan, Technische Universität München, 85354 Freising-Weihenstephan, Germany, German Center for Diabetes Research (DZD), Ingostaedter Landstr. 1, 85764 Neuherberg, Germany and
| | - Stephen Douthwaite
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Nils-Göran Larsson
- Department of Laboratory Medicine, Karolinska Institutet, Retzius väg 8, 171 77 Stockholm, Sweden, Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany
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35
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Moustafa IM, Uchida A, Wang Y, Yennawar N, Cameron CE. Structural models of mammalian mitochondrial transcription factor B2. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1849:987-1002. [PMID: 26066983 DOI: 10.1016/j.bbagrm.2015.05.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 05/22/2015] [Accepted: 05/25/2015] [Indexed: 11/26/2022]
Abstract
Mammalian mitochondrial DNA (mtDNA) encodes 13 core proteins of oxidative phosphorylation, 12S and 16S ribosomal RNAs, and 22 transfer RNAs. Mutations and deletions of mtDNA and/or nuclear genes encoding mitochondrial proteins have been implicated in a wide range of diseases. Thus, cell survival and health of the organism require some steady-state level of the mitochondrial genome and its expression. In mammalian systems, the mitochondrial transcription factor B2 (mtTFB2 or TFB2M) is indispensable for transcription initiation. TFB2M along with two other proteins, mitochondrial RNA polymerase (mtRNAP or POLRMT) and mitochondrial transcription factor A (mtTFA or TFAM), are key components of the core mitochondrial transcription apparatus. Structural information for POLRMT and TFAM from humans is available; however, there is no available structure for TFB2M. In the present study, three-dimensional structure of TFB2M from humans was modeled using a combination of homology modeling and small-angle X-ray scattering (SAXS). The TFB2M structural model adds substantively to our understanding of TFB2M function. An explanation for the low or absent RNA methyltransferase activity is provided. A putative nucleic acid-binding site is revealed. The amino and carboxy termini, while likely lacking defined secondary structure, appear to adopt compact, globular conformations, thus "capping" the ends of the protein. Finally, sites of interaction of TFB2M with other factors, protein and/or nucleic acid, are suggested by the identification of species-specific clusters on the surface of the protein.
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Affiliation(s)
- Ibrahim M Moustafa
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA.
| | - Akira Uchida
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Yao Wang
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Neela Yennawar
- Huck Institutes of Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Craig E Cameron
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA.
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Roberti M, Polosa PL, Bruni F, Deceglie S, Gadaleta MN, Cantatore P. MTERF factors: a multifunction protein family. Biomol Concepts 2015; 1:215-24. [PMID: 25961998 DOI: 10.1515/bmc.2010.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The MTERF family is a large protein family, identified in metazoans and plants, which consists of four subfamilies, MTERF1, 2, 3 and 4. Mitochondrial localisation was predicted for the vast majority of MTERF family members and demonstrated for the characterised MTERF proteins. The main structural feature of MTERF proteins is the presence of a modular architecture, based on repetitions of a 30-residue module, the mTERF motif, containing leucine zipper-like heptads. The MTERF family includes transcription termination factors: human mTERF, sea urchin mtDBP and Drosophila DmTTF. In addition to terminating transcription, they are involved in transcription initiation and in the control of mtDNA replication. This multiplicity of functions seems to flank differences in the gene organisation of mitochondrial genomes. MTERF2 and MTERF3 play antithetical roles in controlling mitochondrial transcription: that is, mammalian and Drosophila MTERF3 act as negative regulators, whereas mammalian MTERF2 functions as a positive regulator. Both proteins contact mtDNA in the promoter region, perhaps establishing interactions, either mutual or with other factors. Regulation of MTERF gene expression in human and Drosophila depends on nuclear transcription factors NRF-2 and DREF, respectively, and proceeds through pathways which appear to discriminate between factors positively or negatively acting in mitochondrial transcription. In this emerging scenario, it appears that MTERF proteins act to coordinate mitochondrial transcription.
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Shutt TE, Bestwick M, Shadel GS. The core human mitochondrial transcription initiation complex: It only takes two to tango. Transcription 2014; 2:55-59. [PMID: 21468229 DOI: 10.4161/trns.2.2.14296] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 11/24/2010] [Accepted: 11/29/2010] [Indexed: 11/19/2022] Open
Abstract
We recently demonstrated that the core transcription initiation complex in human mitochondria is a two-component system (POLRMT and h-mtTFB2). Human mtTFA/TFAM, previously proposed to be a requisite initiation complex member, is dispensable for promoter-specific initiation in vitro. We propose that it instead regulates relative promoter activity and/or overall nucleoid transcription and replication potential.
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Affiliation(s)
- Timothy E Shutt
- Department of Pathology Yale University School of Medicine; New Haven, CT USA
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38
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O'Sullivan M, Rutland P, Lucas D, Ashton E, Hendricks S, Rahman S, Bitner-Glindzicz M. Mitochondrial m.1584A 12S m62A rRNA methylation in families with m.1555A>G associated hearing loss. Hum Mol Genet 2014; 24:1036-44. [PMID: 25305075 PMCID: PMC4986548 DOI: 10.1093/hmg/ddu518] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The mitochondrial DNA mutation m.1555A>G predisposes to hearing loss following aminoglycoside antibiotic exposure in an idiosyncratic dose-independent manner. However, it may also cause maternally inherited hearing loss in the absence of aminoglycoside exposure or any other clinical features (non-syndromic hearing loss). Although m.1555A>G was identified as a cause of deafness more than twenty years ago, the pathogenic mechanism of this mutation of ribosomal RNA remains controversial. Different mechanistic concepts have been proposed. Most recently, evidence from cell lines and animal models suggested that patients with m.1555A>G may have more 12S rRNA N6, N6-dimethyladenosine (m(6) 2A) methylation than controls, so-called 'hypermethylation'. This has been implicated as a pathogenic mechanism of mitochondrial dysfunction but has yet to be validated in patients. 12S m(6) 2A rRNA methylation, by the mitochondrial transcription factor 1 (TFB1M) enzyme, occurs at two successive nucleotides (m.1584A and m.1583A) in close proximity to m.1555A>G. We examined m(6) 2A methylation in 14 patients with m.1555A>G, and controls, and found all detectable 12S rRNA transcripts to be methylated in both groups. Moreover, different RNA samples derived from the same patient (lymphocyte, fibroblast and lymphoblast) revealed that only transformed cells contained some unmethylated 12S rRNA transcripts, with all detectable 12S rRNA transcripts derived from primary samples m(6) 2A-methylated. Our data indicate that TFB1M 12S m(6) 2A rRNA hypermethylation is unlikely to be a pathogenic mechanism and may be an artefact of previous experimental models studied. We propose that RNA methylation studies in experimental models should be validated in primary clinical samples to ensure that they are applicable to the human situation.
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Affiliation(s)
- Mary O'Sullivan
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Paul Rutland
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Deirdre Lucas
- Nuffield Hearing and Speech Centre, Royal National Throat Nose and Ear Hospital, London WC1X 8DA, UK
| | | | - Sebastian Hendricks
- Barnet and Chase Farm Hospitals NHS Trust, Enfield, Middlesex EN2 8JL, UK and
| | - Shamima Rahman
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK, Metabolic Department, Great Ormond Street Hospital for Children NHS Trust, London WC1N 3JH, UK
| | - Maria Bitner-Glindzicz
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK, Centre for Auditory Research, UCL Ear Institute, London WC1X 8EE, UK
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GABP transcription factor (nuclear respiratory factor 2) is required for mitochondrial biogenesis. Mol Cell Biol 2014; 34:3194-201. [PMID: 24958105 DOI: 10.1128/mcb.00492-12] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mitochondria are membrane-bound cytoplasmic organelles that serve as the major source of ATP production in eukaryotic cells. GABP (also known as nuclear respiratory factor 2) is a nuclear E26 transformation-specific transcription factor (ETS) that binds and activates mitochondrial genes that are required for electron transport and oxidative phosphorylation. We conditionally deleted Gabpa, the DNA-binding component of this transcription factor complex, from mouse embryonic fibroblasts (MEFs) to examine the role of Gabp in mitochondrial biogenesis, function, and gene expression. Gabpα loss modestly reduced mitochondrial mass, ATP production, oxygen consumption, and mitochondrial protein synthesis but did not alter mitochondrial morphology, membrane potential, apoptosis, or the expression of several genes that were previously reported to be GABP targets. However, the expression of Tfb1m, a methyltransferase that modifies ribosomal rRNA and is required for mitochondrial protein translation, was markedly reduced in Gabpα-null MEFs. We conclude that Gabp regulates Tfb1m expression and plays an essential, nonredundant role in mitochondrial biogenesis.
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Zurita Rendón O, Silva Neiva L, Sasarman F, Shoubridge EA. The arginine methyltransferase NDUFAF7 is essential for complex I assembly and early vertebrate embryogenesis. Hum Mol Genet 2014; 23:5159-70. [PMID: 24838397 DOI: 10.1093/hmg/ddu239] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Complex I of the mitochondrial respiratory chain is a large multisubunit enzyme that assembles from nuclear and mtDNA-encoded components. Several complex I assembly factors have been identified, but their precise functions are not well understood. Here, we have investigated the function of one of these, NDUFAF7, a soluble matrix protein comprised of a DUF185 domain that harbors a methyltransferase motif. Knockdown of NDUFAF7 by siRNA in human fibroblasts produced a specific complex I assembly defect, as did morpholino-mediated knockdown of the zebrafish ortholog. Germline disruption of the murine ortholog was an early embryonic lethal. The complex I assembly defect was characterized by rapid, AFG3L2-dependent, turnover of newly synthesized ND1, the subunit that seeds the assembly pathway, and by decreased steady-state levels of several other structural subunits including NDUFS2, NDUFS1 and NDUFA9. Expression of an NDUFAF7 mutant (G124V), predicted to disrupt methyltransferase activity, impaired complex I assembly, suggesting an assembly factor or structural subunit as a substrate for methylation. To identify the NDUFAF7 substrate, we used an anti-ND1 antibody to immunoprecipitate complex I and its associated assembly factors, followed by mass spectrometry to detect posttranslational protein modifications. Analysis of an NDUFAF7 methyltransferase mutant showed a 10-fold reduction in an NDUFS2 peptide containing dimethylated Arg85, but a 5-fold reduction in three other NDUFS2 peptides. These results show that NDUFAF7 functions to methylate NDUFS2 after it assembles into a complex I, stabilizing an early intermediate in the assembly pathway, and that this function is essential for normal vertebrate development.
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Affiliation(s)
- Olga Zurita Rendón
- Montreal Neurological Institute and Department of Human Genetics, McGill University, Montreal, QC, Canada H3A 2B4
| | - Lissiene Silva Neiva
- Montreal Neurological Institute and Department of Human Genetics, McGill University, Montreal, QC, Canada H3A 2B4
| | - Florin Sasarman
- Montreal Neurological Institute and Department of Human Genetics, McGill University, Montreal, QC, Canada H3A 2B4
| | - Eric A Shoubridge
- Montreal Neurological Institute and Department of Human Genetics, McGill University, Montreal, QC, Canada H3A 2B4
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41
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Jiang Y, Xia W, Zhu Y, Li X, Wang D, Liu J, Chang H, Li G, Xu B, Chen X, Li Y, Xu S. Mitochondrial dysfunction in early life resulted from perinatal bisphenol A exposure contributes to hepatic steatosis in rat offspring. Toxicol Lett 2014; 228:85-92. [PMID: 24768697 DOI: 10.1016/j.toxlet.2014.04.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/11/2014] [Accepted: 04/17/2014] [Indexed: 12/30/2022]
Abstract
An emerging literature suggests that bisphenol A (BPA), a widespread endocrine disrupting chemical, when exposure occurs in early life, may increase the risk of metabolic syndrome. In this study, we investigated the hypothesis that perinatal exposure to BPA predisposed offspring to fatty liver disease: the hepatic manifestation of metabolic syndrome, and its possible mechanism. Pregnant Wistar rats were administered with BPA (40μg/kg/day) or vehicle during gestation and lactation. Liver histology, biochemical analysis, transcriptome, and mitochondrial function were examined in male offspring at postnatal 3, 15 and 26 weeks. At 3 weeks of age, abnormal liver morphology and function were not observed in the BPA-exposed offspring, but a decrease in mitochondrial respiratory complex (MRC) activity (I and III) and significant changes in gene expression involved in mitochondrial fatty acid metabolism were observed compared with controls. At 15 weeks, micro-vesicular steatosis in liver, up-regulated genes involved in lipogenesis pathways, increased ROS generation and Cytc release were observed in the BPA-exposed offspring. Then, extensive fatty accumulation in liver and elevated serum ALT were observed in BPA-exposed offspring at 26 weeks. In the longitudinal observation, hepatic mitochondrial function including MRC activity, ATP production, ROS generation and mitochondrial membrane potential were progressively worsened in the BPA-exposed offspring. Perinatal BPA exposure contributes to the development of hepatic steatosis in the offspring of rats, which may be mediated through impaired hepatic mitochondrial function and up-regulated hepatic lipid metabolism.
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Affiliation(s)
- Ying Jiang
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wei Xia
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yingshuang Zhu
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiaocui Li
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Danqi Wang
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Juan Liu
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Huailong Chang
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Gengqi Li
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Bing Xu
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xi Chen
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yuanyuan Li
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Shunqing Xu
- Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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42
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Xia W, Jiang Y, Li Y, Wan Y, Liu J, Ma Y, Mao Z, Chang H, Li G, Xu B, Chen X, Xu S. Early-life exposure to bisphenol a induces liver injury in rats involvement of mitochondria-mediated apoptosis. PLoS One 2014; 9:e90443. [PMID: 24587367 PMCID: PMC3938763 DOI: 10.1371/journal.pone.0090443] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 01/31/2014] [Indexed: 01/23/2023] Open
Abstract
Exposure to bisphenol A (BPA), a monomer widely used to manufacture polycarbonate plastics, has been reported to be associated with abnormalities of liver function and hepatic damage. However, the molecular mechanism under the pathogenesis of hepatic injury is unclear. In this study, the effect of perinatal exposure to BPA at the reference dose of 50 µg/kg/day on the apoptotic index in the liver of rat offspring was investigated. Increased levels of ALT and enhanced cell apoptosis were observed in the liver of rat offspring at 15 and 21 weeks, and significantly increased activity of caspase-3 and caspase-9 and elevated levels of cytochrome c were also confirmed. In addition, significant change in the expression levels of Bcl-2 and Bax were found in BPA-treated offspring at 21 weeks. For in vitro experiments, liver mitochondria were isolated from neonatal rats and were treated with BPA. BPA treatment led to a significant increase in mitochondrial permeability transition. Moreover, the supernatant from BPA-treated mitochondria significantly increased apoptotic changes in nuclei isolated from liver tissue. In conclusion, the study demonstrates that BPA induces mitochondria-mediated apoptosis in hepatic cells, which may contribute to long-term hepatotoxicity induced by early-life exposure to BPA.
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Affiliation(s)
- Wei Xia
- Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ying Jiang
- Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuanyuan Li
- Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yanjian Wan
- Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Juan Liu
- Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yue Ma
- Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhenxing Mao
- Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huailong Chang
- Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Gengqi Li
- Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bing Xu
- Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xi Chen
- Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shunqing Xu
- Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, and State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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43
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Raimundo N. Mitochondrial pathology: stress signals from the energy factory. Trends Mol Med 2014; 20:282-92. [PMID: 24508276 DOI: 10.1016/j.molmed.2014.01.005] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 01/06/2014] [Accepted: 01/08/2014] [Indexed: 12/16/2022]
Abstract
Mitochondria are undergoing a renaissance. The cellular power plant is now recognized as a key cellular signaling platform. The signals released by mitochondria are currently an area of intense research. A complex network is emerging involving metabolic intermediates, the roles of the mitochondrial unfolded protein response, and the interaction of mitochondria with other organelles and with the cellular autophagic system. Despite the diversity of the perturbations leading to mitochondrial diseases, some emerging trends are apparent. The long-held notion that mitochondrial diseases result from decreased mitochondrial energy output has been challenged by new data showing that mitochondrial pathological signaling can cause disease irrespective of the energy output. This review proposes a novel integrative view of mitochondrial signaling in physiology and disease.
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Affiliation(s)
- Nuno Raimundo
- University Medical Center Goettingen, Institute for Cellular Biochemistry, Humboldtallee 23, Room 01.423, 37073 Goettingen, Germany.
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44
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Yakubovskaya E, Guja KE, Eng ET, Choi WS, Mejia E, Beglov D, Lukin M, Kozakov D, Garcia-Diaz M. Organization of the human mitochondrial transcription initiation complex. Nucleic Acids Res 2014; 42:4100-12. [PMID: 24413562 PMCID: PMC3973321 DOI: 10.1093/nar/gkt1360] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Initiation of transcription in human mitochondria involves two factors, TFAM and TFB2M, in addition to the mitochondrial RNA polymerase, POLRMT. We have investigated the organization of the human mitochondrial transcription initiation complex on the light-strand promoter (LSP) through solution X-ray scattering, electron microscopy (EM) and biochemical studies. Our EM results demonstrate a compact organization of the initiation complex, suggesting that protein–protein interactions might help mediate initiation. We demonstrate that, in the absence of DNA, only POLRMT and TFAM form a stable interaction, albeit one with low affinity. This is consistent with the expected transient nature of the interactions necessary for initiation and implies that the promoter DNA acts as a scaffold that enables formation of the full initiation complex. Docking of known crystal structures into our EM maps results in a model for transcriptional initiation that strongly correlates with new and existing biochemical observations. Our results reveal the organization of TFAM, POLRMT and TFB2M around the LSP and represent the first structural characterization of the entire mitochondrial transcriptional initiation complex.
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Affiliation(s)
- Elena Yakubovskaya
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, Cryo-Electron Microscopy Facility, New York Structural Biology Center, New York, NY 10027 and Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
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45
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Iacobazzi V, Castegna A, Infantino V, Andria G. Mitochondrial DNA methylation as a next-generation biomarker and diagnostic tool. Mol Genet Metab 2013; 110:25-34. [PMID: 23920043 DOI: 10.1016/j.ymgme.2013.07.012] [Citation(s) in RCA: 168] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/12/2013] [Accepted: 07/12/2013] [Indexed: 10/26/2022]
Abstract
Recent expansion of our knowledge on epigenetic changes strongly suggests that not only nuclear DNA (nDNA), but also mitochondrial DNA (mtDNA) may be subjected to epigenetic modifications related to disease development, environmental exposure, drug treatment and aging. Thus, mtDNA methylation is attracting increasing attention as a potential biomarker for the detection and diagnosis of diseases and the understanding of cellular behavior in particular conditions. In this paper we review the current advances in mtDNA methylation studies with particular attention to the evidences of mtDNA methylation changes in diseases and physiological conditions so far investigated. Technological advances for the analysis of epigenetic variations are promising tools to provide insights into methylation of mtDNA with similar resolution levels as those reached for nDNA. However, many aspects related to mtDNA methylation are still unclear. More studies are needed to understand whether and how changes in mtDNA methylation patterns, global and gene specific, are associated to diseases or risk factors.
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Affiliation(s)
- Vito Iacobazzi
- Department of Biosciences, Biotechnology and Pharmacological Sciences, University of Bari, via Orabona 4, 70125 Bari, Italy.
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46
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DING YU, XIA BOHOU, YU JINFANG, LENG JIANHANG, HUANG JINYU. Mitochondrial DNA mutations and essential hypertension (Review). Int J Mol Med 2013; 32:768-74. [DOI: 10.3892/ijmm.2013.1459] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 07/22/2013] [Indexed: 11/06/2022] Open
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Manna S, Le P, Barth C. A unique mitochondrial transcription factor B protein in Dictyostelium discoideum. PLoS One 2013; 8:e70614. [PMID: 23923009 PMCID: PMC3724811 DOI: 10.1371/journal.pone.0070614] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 06/20/2013] [Indexed: 11/19/2022] Open
Abstract
Unlike their bacteriophage homologs, mitochondrial RNA polymerases require the assistance of transcription factors in order to transcribe mitochondrial DNA efficiently. The transcription factor A family has been shown to be important for transcription of the human mitochondrial DNA, with some of its regulatory activity located in its extended C-terminal tail. The mitochondrial transcription factor B family often has functions not only in transcription, but also in mitochondrial rRNA modification, a hallmark of its α-proteobacterial origin. We have identified and characterised a mitochondrial transcription factor B homolog in the soil dwelling cellular slime mould Dictyostelium discoideum, an organism widely established as a model for studying eukaryotic cell biology. Using in bacterio functional assays, we demonstrate that the mitochondrial transcription factor B homolog not only functions as a mitochondrial transcription factor, but that it also has a role in rRNA methylation. Additionally, we show that the transcriptional activation properties of the D. discoideum protein are located in its extended C-terminal tail, a feature not seen before in the mitochondrial transcription factor B family, but reminiscent of the human mitochondrial transcription factor A. This report contributes to our current understanding of the complexities of mitochondrial transcription, and its evolution in eukaryotes.
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Affiliation(s)
- Sam Manna
- Department of Microbiology, La Trobe University, Melbourne, Victoria, Australia
| | - Phuong Le
- Tokyo Metropolitan University, Department of Biological Science, Tokyo, Japan
| | - Christian Barth
- Department of Microbiology, La Trobe University, Melbourne, Victoria, Australia
- * E-mail:
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48
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Guja KE, Venkataraman K, Yakubovskaya E, Shi H, Mejia E, Hambardjieva E, Karzai AW, Garcia-Diaz M. Structural basis for S-adenosylmethionine binding and methyltransferase activity by mitochondrial transcription factor B1. Nucleic Acids Res 2013; 41:7947-59. [PMID: 23804760 PMCID: PMC3763538 DOI: 10.1093/nar/gkt547] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Eukaryotic transcription factor B (TFB) proteins are homologous to KsgA/Dim1 ribosomal RNA (rRNA) methyltransferases. The mammalian TFB1, mitochondrial (TFB1M) factor is an essential protein necessary for mitochondrial gene expression. TFB1M mediates an rRNA modification in the small ribosomal subunit and thus plays a role analogous to KsgA/Dim1 proteins. This modification has been linked to mitochondrial dysfunctions leading to maternally inherited deafness, aminoglycoside sensitivity and diabetes. Here, we present the first structural characterization of the mammalian TFB1 factor. We have solved two X-ray crystallographic structures of TFB1M with (2.1 Å) and without (2.0 Å) its cofactor S-adenosyl-L-methionine. These structures reveal that TFB1M shares a conserved methyltransferase core with other KsgA/Dim1 methyltransferases and shed light on the structural basis of S-adenosyl-L-methionine binding and methyltransferase activity. Together with mutagenesis studies, these data suggest a model for substrate binding and provide insight into the mechanism of methyl transfer, clarifying the role of this factor in an essential process for mitochondrial function.
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Affiliation(s)
- Kip E Guja
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA, Medical Scientist Training Program, Stony Brook University Medical Center, Stony Brook, NY 11794, USA and Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794, USA
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49
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Bestwick ML, Shadel GS. Accessorizing the human mitochondrial transcription machinery. Trends Biochem Sci 2013; 38:283-91. [PMID: 23632312 PMCID: PMC3698603 DOI: 10.1016/j.tibs.2013.03.006] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/18/2013] [Accepted: 03/26/2013] [Indexed: 12/29/2022]
Abstract
The human genome comprises large chromosomes in the nucleus and mitochondrial DNA (mtDNA) housed in the dynamic mitochondrial network. Human cells contain up to thousands of copies of the double-stranded, circular mtDNA molecule that encodes essential subunits of the oxidative phosphorylation complexes and the rRNAs and tRNAs needed to translate these in the organelle matrix. Transcription of human mtDNA is directed by a single-subunit RNA polymerase, POLRMT, which requires two primary transcription factors, TFB2M (transcription factor B2, mitochondrial) and TFAM (transcription factor A, mitochondrial), to achieve basal regulation of the system. Here, we review recent advances in understanding the structure and function of the primary human transcription machinery and the other factors that facilitate steps in transcription beyond initiation and provide more intricate control over the system.
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Affiliation(s)
- Megan L. Bestwick
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520
| | - Gerald S. Shadel
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06520
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Luo LF, Hou CC, Yang WX. Nuclear factors: roles related to mitochondrial deafness. Gene 2013; 520:79-89. [PMID: 23510774 DOI: 10.1016/j.gene.2013.03.041] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 03/08/2013] [Indexed: 12/16/2022]
Abstract
Hearing loss (HL) is a common disorder with mitochondrial dysfunction as one of the major causes leading to deafness. Mitochondrial dysfunction may be caused by either mutations in nuclear genes leading to defective nuclear-encoded proteins or mutations in mitochondrial genes leading to defective mitochondrial-encoded products. The specific nuclear genes involved in HL can be classified into two categories depending on whether mitochondrial gene mutations co-exist (modifier genes) or not (deafness-causing genes). TFB1M, MTO1, GTPBP3, and TRMU are modifier genes. A mutation in any of these modifier genes may lead to a deafness phenotype when accompanied by the mitochondrial gene mutation. OPA1, TIMM8A, SMAC/DIABLO, MPV17, PDSS1, BCS1L, SUCLA2, C10ORF2, COX10, PLOG1and RRM2B are deafness-causing genes. A mutation in any of these deafness-causing genes will directly induce variable phenotypic HL.
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Affiliation(s)
- Ling-Feng Luo
- Institute of Cell and Developmental Biology, Zhejiang University, Hangzhou 310058, China
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