101
|
Abstract
Primordial germ cells (PGCs) must complete a complex and dynamic developmental program during embryogenesis to establish the germline. This process is highly conserved and involves a diverse array of tasks required of PGCs, including migration, survival, sex differentiation, and extensive epigenetic reprogramming. A common theme across many organisms is that PGC success is heterogeneous: only a portion of all PGCs complete all these steps while many other PGCs are eliminated from further germline contribution. The differences that distinguish successful PGCs as a population are not well understood. Here, we examine variation that exists in PGCs as they navigate the many stages of this developmental journey. We explore potential sources of PGC heterogeneity and their potential implications in affecting germ cell behaviors. Lastly, we discuss the potential for PGC development to function as a multistage selection process that assesses heterogeneity in PGCs to refine germline quality.
Collapse
Affiliation(s)
- Daniel H Nguyen
- Department of Obstetrics, Gynecology and Reproductive Science, Center for Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, United States
| | - Rebecca G Jaszczak
- Department of Obstetrics, Gynecology and Reproductive Science, Center for Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, United States
| | - Diana J Laird
- Department of Obstetrics, Gynecology and Reproductive Science, Center for Reproductive Sciences, Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA, United States.
| |
Collapse
|
102
|
Jiang S, Koolmeister C, Misic J, Siira S, Kühl I, Silva Ramos E, Miranda M, Jiang M, Posse V, Lytovchenko O, Atanassov I, Schober FA, Wibom R, Hultenby K, Milenkovic D, Gustafsson CM, Filipovska A, Larsson NG. TEFM regulates both transcription elongation and RNA processing in mitochondria. EMBO Rep 2019; 20:embr.201948101. [PMID: 31036713 PMCID: PMC6549021 DOI: 10.15252/embr.201948101] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 03/29/2019] [Accepted: 04/02/2019] [Indexed: 12/22/2022] Open
Abstract
Regulation of replication and expression of mitochondrial DNA (mtDNA) is essential for cellular energy conversion via oxidative phosphorylation. The mitochondrial transcription elongation factor (TEFM) has been proposed to regulate the switch between transcription termination for replication primer formation and processive, near genome‐length transcription for mtDNA gene expression. Here, we report that Tefm is essential for mouse embryogenesis and that levels of promoter‐distal mitochondrial transcripts are drastically reduced in conditional Tefm‐knockout hearts. In contrast, the promoter‐proximal transcripts are much increased in Tefm knockout mice, but they mostly terminate before the region where the switch from transcription to replication occurs, and consequently, de novo mtDNA replication is profoundly reduced. Unexpectedly, deep sequencing of RNA from Tefm knockouts revealed accumulation of unprocessed transcripts in addition to defective transcription elongation. Furthermore, a proximity‐labeling (BioID) assay showed that TEFM interacts with multiple RNA processing factors. Our data demonstrate that TEFM acts as a general transcription elongation factor, necessary for both gene transcription and replication primer formation, and loss of TEFM affects RNA processing in mammalian mitochondria.
Collapse
Affiliation(s)
- Shan Jiang
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Camilla Koolmeister
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Jelena Misic
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Stefan Siira
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Inge Kühl
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne, Germany.,Institute of Integrative Biology of the Cell, UMR9198, CEA, CNRS, University Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Eduardo Silva Ramos
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Maria Miranda
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Min Jiang
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Viktor Posse
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Oleksandr Lytovchenko
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Ilian Atanassov
- Proteomics Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Florian A Schober
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Rolf Wibom
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| | - Kjell Hultenby
- Division of Clinical Research Centre, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Dusanka Milenkovic
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Claes M Gustafsson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia
| | - Nils-Göran Larsson
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden .,Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden.,Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne, Germany.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden
| |
Collapse
|
103
|
Li G, Qin Y. Mitochondrial translation factor EF4 regulates oxidative phosphorylation complexes and the production of ROS. Free Radic Res 2019; 52:1250-1255. [PMID: 30693836 DOI: 10.1080/10715762.2018.1479063] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mitochondrial translation system executes the biosynthesis of mitochondrial DNA encoded polypeptides that are the core subunits of oxidative phosphorylation complexes. Recently, we reported that elongation factor 4 (EF4) is a key quality control factor in bacterial and mitochondrial translation regulating tRNA translocation and modulating cellular responses via a direct cross-talk with cytoplasmic translation machinery. Here, we made a brief review on mtEF4-regulated mitochondrial translation, respiratory chain biogenesis and the production of reactive oxygen species (ROS). We will discuss the influence of mtEF4 on the electron transport chain, especially at respiratory chain complex IV, which could result in cytochrome c peroxidase formation, electron leakage from electron transport chain and ROS increase.
Collapse
Affiliation(s)
- Guichen Li
- a Key Laboratory of RNA Biology , Institute of Biophysics, Chinese Academy of Sciences , Chaoyang District , Beijing , China
| | - Yan Qin
- a Key Laboratory of RNA Biology , Institute of Biophysics, Chinese Academy of Sciences , Chaoyang District , Beijing , China.,b University of Chinese Academy of Sciences , Beijing , China
| |
Collapse
|
104
|
Strieskova L, Gazdaricova I, Kajsik M, Soltys K, Budis J, Pos O, Lickova M, Klempa B, Szemes T. Ultracentrifugation enrichment protocol followed by total RNA sequencing allows assembly of the complete mitochondrial genome. J Biotechnol 2019; 299:8-12. [PMID: 31022426 DOI: 10.1016/j.jbiotec.2019.04.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/18/2019] [Accepted: 04/20/2019] [Indexed: 12/23/2022]
Abstract
The mitochondrial genome is an independent genetic system in each eukaryotic cell outside the nuclear genome. Mitochondrial DNA (mtDNA) appears in high copy number within one cell, unlike nuclear DNA, which exists in two copies. But nevertheless, mtDNA represent only small part of total cellular DNA what causes problematic analysis and identification of relevant mutations. While most researchers tend to overlook it because of its small size, the mitochondrial genome contains genes that are essential for cellular energetics and survival. Because of the increased awareness on the importance of metabolism and bioenergetics in a wide variety of human diseases, more and more mtDNA studies were performed. Mitochondrial genome research has established the connection between mtDNA and a wide variety of diseases such as cancer or neurodegenerative disorders. At the present time, several methods are known, that allow sequencing of mtDNA. However, genomic analysis is often complicated due to the low content of mtDNA compared to nuclear DNA. For this reason, we have designed a new approach to obtaining the genomic mitochondrial sequence. We chose RNA based sequencing. Since human mtDNA does not contain introns, the reconstruction of whole mitochondrial genome through RNA sequencing seems to be effective. Our method is based on total RNA sequencing coupled with simple ultracentrifugation protocol and de novo assembly. Following our protocol, we were able to assemble a complete mammalian mitochondrial genome with a length of 16,505 bp and an average coverage of 156. The method is a relatively simple and inexpensive which could help in the further research or diagnostics of mtDNA-based diseases.
Collapse
Affiliation(s)
| | - Iveta Gazdaricova
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Michal Kajsik
- Comenius University Science Park, Bratislava, Slovakia
| | - Katarina Soltys
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia; Comenius University Science Park, Bratislava, Slovakia
| | - Jaroslav Budis
- Geneton Ltd., Bratislava, Slovakia; Comenius University Science Park, Bratislava, Slovakia; Slovak Centre of Scientific and Technical Information, Bratislava, Slovakia
| | - Ondrej Pos
- Geneton Ltd., Bratislava, Slovakia; Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia.
| | - Martina Lickova
- Institute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Boris Klempa
- Institute of Virology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Tomas Szemes
- Geneton Ltd., Bratislava, Slovakia; Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia; Comenius University Science Park, Bratislava, Slovakia
| |
Collapse
|
105
|
Khan S, Roberts J, Wu SB. Genes involved in mitochondrial biogenesis and function may not show synchronised responses to mitochondria in shell gland of laying chickens under infectious bronchitis virus challenge. BMC Mol Cell Biol 2019; 20:3. [PMID: 31041887 PMCID: PMC6446503 DOI: 10.1186/s12860-019-0190-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 03/21/2019] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Egg formation takes place in the oviduct of laying hens over a 24 h period. Infectious bronchitis virus (IBV) causes pathological lesions in the chicken oviduct. In the current study, mitochondrial counts were determined in three different segments of the oviduct during egg formation in laying chickens challenged with IBV T strain. Nuclear DNA encoded genes that are involved in mitochondrial biogenesis, fission and function were studied in the shell gland of the oviduct undergoing virus multiplication. RESULTS In the shell gland, the mitochondrial count was significantly lower (P < 0.05) in the challenged group, compared with the control group. However, it did not vary in response to IBV challenge in the isthmus and magnum regions of the oviduct. The gene succinate dehydrogenase complex, subunit A, flavoprotein variant (SDHA) was down-regulated in the shell gland by IBV challenge (P < 0.05), while other genes being studied did not show responses to the challenge (P > 0.05). Differential expression of the genes was observed at different time-points of egg-shell formation. The expression levels of citrate synthase (CS), cytochrome C, somatic (CYC, S) and sodium-potassium adenosine triphosphatase (Na+-K+ATPase) genes were significantly higher, while those of SDHA and dynamin related protein 1 (Drp1) genes were significantly lower, at 15 h compared with 5 h following oviposition of the previous egg. The expression level of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) did not show significant change at different time-points. CONCLUSIONS It was concluded that IBV T strain infection in laying hens reduced mitochondrial counts only in the shell gland region of the oviduct. The genes involved in mitochondrial biogenesis or function may not show synchronised responses to that of mitochondria in the shell gland of chickens under T strain of IBV challenge.
Collapse
Affiliation(s)
- Samiullah Khan
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351 Australia
- Present address: School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, South Australia 5371 Australia
| | - Juliet Roberts
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351 Australia
| | - Shu-Biao Wu
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351 Australia
| |
Collapse
|
106
|
Nissanka N, Minczuk M, Moraes CT. Mechanisms of Mitochondrial DNA Deletion Formation. Trends Genet 2019; 35:235-244. [PMID: 30691869 DOI: 10.1016/j.tig.2019.01.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 02/02/2023]
Abstract
Mitochondrial DNA (mtDNA) encodes a subset of genes which are essential for oxidative phosphorylation. Deletions in the mtDNA can ablate a number of these genes and result in mitochondrial dysfunction, which is associated with bona fide mitochondrial disorders. Although mtDNA deletions are thought to occur as a result of replication errors or following double-strand breaks, the exact mechanism(s) behind deletion formation have yet to be determined. In this review we discuss the current knowledge about the fate of mtDNA following double-strand breaks, including the molecular players which mediate the degradation of linear mtDNA fragments and possible mechanisms of recircularization. We propose that mtDNA deletions formed from replication errors versus following double-strand breaks can be mediated by separate pathways.
Collapse
Affiliation(s)
- Nadee Nissanka
- Department of Neurology, University of Miami, Miller School of Medicine, FL 33136, USA
| | - Michal Minczuk
- Medical Research Council (MRC) Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Carlos T Moraes
- Department of Neurology, University of Miami, Miller School of Medicine, FL 33136, USA.
| |
Collapse
|
107
|
Krasilnikova J, Lauberte L, Stoyanova E, Abadjieva D, Chervenkov M, Mori M, De Paolis E, Mladenova V, Telysheva G, Botta B, Kistanova E. Oregonin from Alnus incana bark affects DNA methyltransferases expression and mitochondrial DNA copies in mouse embryonic fibroblasts. J Enzyme Inhib Med Chem 2018; 33:1055-1063. [PMID: 29877148 PMCID: PMC6010114 DOI: 10.1080/14756366.2018.1476504] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 01/24/2023] Open
Abstract
Oregonin is an open-chain diarylheptanoid isolated from Alnus incana bark that possesses remarkable antioxidant and anti-inflammatory properties, inhibits adipogenesis, and can be used in the prevention of obesity and related metabolic disorders. Here, we aimed to investigate the effects of oregonin on the epigenetic regulation in cells as well as its ability to modulate DNA methylating enzymes expression and mitochondrial DNA (mtDNA) copies. Our results show that oregonin altered the expression of DNA methyltransferases and mtDNA copy numbers in dependency on concentration and specificity of cells genotype. A close correlation between mtDNA copy numbers and mRNA expression of the mtDnmt1 and Dnmt3b was established. Moreover, molecular modeling suggested that oregonin fits the catalytic site of DNMT1 and partially overlaps with binding of the cofactor. These findings further extend the knowledge on oregonin, and elucidate for the first time its potential to affect the key players of the DNA methylation process, namely DNMTs transcripts and mtDNA.
Collapse
Affiliation(s)
| | - Liga Lauberte
- Latvian State Institute of Wood Chemistry, Riga, Latvia
| | - Elena Stoyanova
- Institute of Biology and Immunology of Reproduction, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Desislava Abadjieva
- Institute of Biology and Immunology of Reproduction, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Mihail Chervenkov
- Faculty of Veterinary Medicine, University of Forestry, Sofia, Bulgaria
- Institute of Neurobiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Mattia Mori
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
| | - Elisa De Paolis
- Department of Chemistry and Technology of Drugs, Sapienza University of Rome, Rome, Italy
| | - Vanya Mladenova
- Institute of Biology and Immunology of Reproduction, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | | | - Bruno Botta
- Department of Chemistry and Technology of Drugs, Sapienza University of Rome, Rome, Italy
| | - Elena Kistanova
- Institute of Biology and Immunology of Reproduction, Bulgarian Academy of Sciences, Sofia, Bulgaria
| |
Collapse
|
108
|
Palozzi JM, Jeedigunta SP, Hurd TR. Mitochondrial DNA Purifying Selection in Mammals and Invertebrates. J Mol Biol 2018; 430:4834-4848. [DOI: 10.1016/j.jmb.2018.10.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 10/20/2018] [Accepted: 10/25/2018] [Indexed: 01/19/2023]
|
109
|
Hashiya F, Ito S, Sugiyama H. Electron injection from mitochondrial transcription factor A to DNA associated with thymine dimer photo repair. Bioorg Med Chem 2018; 27:278-284. [PMID: 30552005 DOI: 10.1016/j.bmc.2018.11.044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 01/11/2023]
Abstract
Electron transfer through π-stacked arrays of double-stranded DNA contributes to the redox chemistry of bases, including guanine oxidation and thymine-thymine dimer repair by photolyase. 5-Bromouracil is an attractive photoreactive thymine analogue that can be used to investigate electron transfer in DNA, and is a useful probe for protein-DNA interaction analysis. In the present study using BrU we found that UV irradiation facilitated electron injection from mitochondrial transcription factor A into DNA. We also observed that this electron injection could lead to repair of a thymine-thymine dimer.
Collapse
Affiliation(s)
- Fumitaka Hashiya
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto 606-8502, Japan
| | - Shinji Ito
- Medical Research Support Center, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto 606-8502, Japan; Institute for Integrated Cell-Material Sciences, Institute for Advanced Study, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
| |
Collapse
|
110
|
Yu H, Xue C, Long M, Jia H, Xue G, Du S, Coello Y, Ishibashi T. TEFM Enhances Transcription Elongation by Modifying mtRNAP Pausing Dynamics. Biophys J 2018; 115:2295-2300. [PMID: 30514634 DOI: 10.1016/j.bpj.2018.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/25/2018] [Accepted: 11/05/2018] [Indexed: 10/27/2022] Open
Abstract
Regulation of transcription elongation is one of the key mechanisms employed to control gene expression. The single-subunit mitochondrial RNA polymerase (mtRNAP) transcribes mitochondrial genes, such as those related to ATP synthesis. We investigated how mitochondrial transcription elongation factor (TEFM) enhances mtRNAP transcription elongation using a single-molecule optical-tweezers transcription assay, which follows transcription dynamics in real time and allows the separation of pause-free elongation from transcriptional pauses. We found that TEFM enhances the stall force of mtRNAP. Although TEFM does not change the pause-free elongation rate, it enhances mtRNAP transcription elongation by reducing the frequency of long-lived pauses and shortening their durations. Furthermore, we demonstrate how mtRNAP passes through the conserved sequence block II, which is the key sequence for the switch between DNA replication and transcription in mitochondria. Our findings elucidate how both TEFM and mitochondrial genomic DNA sequences directly control the transcription elongation dynamics of mtRNAP.
Collapse
Affiliation(s)
- Hongwu Yu
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Cheng Xue
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Mengping Long
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Huiqiang Jia
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Guosheng Xue
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China; Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Shengwang Du
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China; Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China
| | - Yves Coello
- Departamento de Ciencias, Sección Química, Pontificia Universidad Católica del Perú PUCP, Lima, Peru
| | - Toyotaka Ishibashi
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, NT, Hong Kong, HKSAR, China.
| |
Collapse
|
111
|
Park CB, Choi VN, Jun JB, Kim JH, Lee Y, Lee J, Lim G, Kim J, Jeong SY, Yim SY. Identification of a rare homozygous c.790C>T variation in the TFB2M gene in Korean patients with autism spectrum disorder. Biochem Biophys Res Commun 2018; 507:148-154. [PMID: 30414672 DOI: 10.1016/j.bbrc.2018.10.194] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 10/30/2018] [Indexed: 11/30/2022]
Abstract
Mitochondrial dysfunction and subsequent enhanced oxidative stress is implicated in the pathogenesis of autism spectrum disorder (ASD). Mitochondrial transcription factor B2 (TFB2M) is an essential protein in mitochondrial gene expression. No reports have described TFB2M mutations and variations involved in any human diseases. We identified a rare homozygous c.790C>T (His264Tyr) variation in TFB2M gene in two Korean siblings with ASD by whole-exome sequencing. The roles of the TFB2M variation in the pathogenesis of ASD were investigated. Patient fibroblasts revealed increased transcription of mitochondrial genes and mitochondrial function in terms of ATP, membrane potential, oxygen consumption, and reactive oxygen species (ROS). Overexpression of the TFB2M variant in primary-cultured fibroblasts demonstrated significantly increased transcription of mitochondrial genes and mitochondrial function compared with overexpression of wild-type TFB2M. Molecular dynamics simulation of the TFB2M variant protein suggested an increase in the rigidity of the hinge region, which may cause alterations in loading and/or unloading of TFB2M on target DNA. Our results suggest that augmentation of mitochondrial gene expression and subsequent enhancement of mitochondrial function may be associated with the pathogenesis of ASD in Korean patients.
Collapse
Affiliation(s)
- Chan Bae Park
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, 16499, Republic of Korea; Department of Physiology, Ajou University School of Medicine, Suwon, 16499, Republic of Korea
| | - Vit-Na Choi
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, 16499, Republic of Korea; Department of Medical Genetics, Ajou University School of Medicine, Suwon, 16499, Republic of Korea
| | - Jae-Bum Jun
- Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, 04763, Republic of Korea
| | - Ji-Hae Kim
- Institute of Rheumatology, Hanyang University, Seoul, 04763, Republic of Korea
| | - Youngsoo Lee
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, 16499, Republic of Korea; Genomic Instability Research Center, Ajou University School of Medicine, Suwon, 16499, Republic of Korea
| | - Jinhyuk Lee
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea; Department of Bioinformatics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, 34113, Republic of Korea
| | - GyuTae Lim
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea; Department of Bioinformatics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, 34113, Republic of Korea
| | - Jeonghyun Kim
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, 16499, Republic of Korea; Department of Medical Genetics, Ajou University School of Medicine, Suwon, 16499, Republic of Korea
| | - Seon-Yong Jeong
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, 16499, Republic of Korea; Department of Medical Genetics, Ajou University School of Medicine, Suwon, 16499, Republic of Korea.
| | - Shin-Young Yim
- Department of Medical Genetics, Ajou University School of Medicine, Suwon, 16499, Republic of Korea; Department of Physical Medicine and Rehabilitation, Ajou University School of Medicine, Suwon, 16499, Republic of Korea.
| |
Collapse
|
112
|
Mafra D, Gidlund EK, Borges NA, Magliano DC, Lindholm B, Stenvinkel P, von Walden F. Bioactive food and exercise in chronic kidney disease: Targeting the mitochondria. Eur J Clin Invest 2018; 48:e13020. [PMID: 30144313 DOI: 10.1111/eci.13020] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 08/11/2018] [Accepted: 08/22/2018] [Indexed: 12/16/2022]
Abstract
Chronic kidney disease (CKD), which affects 10%-15% of the population, associates with a range of complications-such as cardiovascular disease, frailty, infections, muscle and bone disorders and premature ageing-that could be related to alterations of mitochondrial number, distribution, structure and function. As mitochondrial biogenesis, bioenergetics and the dynamic mitochondrial networks directly or indirectly regulate numerous intra- and extracellular functions, the mitochondria have emerged as an important target for interventions aiming at preventing or improving the treatment of complications in CKD. In this review, we discuss the possible role of bioactive food compounds and exercise in the modulation of the disturbed mitochondrial function in a uraemic milieu.
Collapse
Affiliation(s)
- Denise Mafra
- Graduate Program in Medical Sciences, Fluminense Federal University (UFF), Niterói, Rio de Janeiro, Brazil.,Graduate Program in Cardiovascular Sciences, Fluminense Federal University (UFF), Niterói, Rio de Janeiro, Brazil
| | - Eva-Karin Gidlund
- Division of Molecular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Natália Alvarenga Borges
- Graduate Program in Cardiovascular Sciences, Fluminense Federal University (UFF), Niterói, Rio de Janeiro, Brazil
| | - D'Angelo Carlo Magliano
- Graduate Program in Cardiovascular Sciences, Fluminense Federal University (UFF), Niterói, Rio de Janeiro, Brazil
| | - Bengt Lindholm
- Division of Renal Medicine, Department of Clinical Science Intervention and Technology, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Peter Stenvinkel
- Division of Renal Medicine, Department of Clinical Science Intervention and Technology, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Ferdinand von Walden
- Division of Pediatric Neurology, Department of Women's and Children's health, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
113
|
Bioenergetic consequences of compromised mitochondrial DNA repair in the mouse heart. Biochem Biophys Res Commun 2018; 504:742-748. [PMID: 30217445 DOI: 10.1016/j.bbrc.2018.09.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 09/05/2018] [Indexed: 12/13/2022]
Abstract
The progeroid phenotype of mitochondrial DNA (mtDNA) mutator mice has been nebulously attributed to general mitochondrial 'dysfunction', though few studies have rigorously defined the bioenergetic consequences of accumulating mtDNA mutations. Comprehensive mitochondrial diagnostics was employed to interrogate the bioenergetic properties of isolated cardiac mitochondria from mtDNA mutator mice and wild type littermates. Assessment of respiratory flux in conjunction with parallel measurements of mitochondrial free energy all point to the cause of respiratory flux limitations observed in mtDNA mutator mouse mitochondria being due to impairments within the energy transduction step catalyzed by the electron transport system in which NADH/NAD+ free energy is transduced to the proton motive force (ΔP). The primary bioenergetic consequence of this limitation appears to be hyper-reduction of NAD(P)H/NAD(P)+ redox poise across multiple substrate conditions, particularly evident at moderate to high respiration rates. This hyper-reduced phenotype appears to result from specific reductions in both complex I and complex IV expression, presumably due to compromised mtDNA integrity. Translation of these findings to the working heart would suggest that the primary biological consequence of accumulated mtDNA damage is accelerated electron leak driven by an increase in electron redox pressure for a given rate of oxygen consumption.
Collapse
|
114
|
Structural basis of mitochondrial transcription. Nat Struct Mol Biol 2018; 25:754-765. [PMID: 30190598 DOI: 10.1038/s41594-018-0122-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/29/2018] [Indexed: 01/17/2023]
Abstract
The mitochondrial genome is transcribed by a single-subunit DNA-dependent RNA polymerase (mtRNAP) and its auxiliary factors. Structural studies have elucidated how mtRNAP cooperates with its dedicated transcription factors to direct RNA synthesis: initiation factors TFAM and TFB2M assist in promoter-DNA binding and opening by mtRNAP while the elongation factor TEFM increases polymerase processivity to the levels required for synthesis of long polycistronic mtRNA transcripts. Here, we review the emerging body of structural and functional studies of human mitochondrial transcription, provide a molecular movie that can be used for teaching purposes and discuss the open questions to guide future directions of investigation.
Collapse
|
115
|
Ma H, Lee Y, Hayama T, Van Dyken C, Marti-Gutierrez N, Li Y, Ahmed R, Koski A, Kang E, Darby H, Gonmanee T, Park Y, Wolf DP, Jai Kim C, Mitalipov S. Germline and somatic mtDNA mutations in mouse aging. PLoS One 2018; 13:e0201304. [PMID: 30040856 PMCID: PMC6057648 DOI: 10.1371/journal.pone.0201304] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 07/11/2018] [Indexed: 12/13/2022] Open
Abstract
The accumulation of acquired mitochondrial genome (mtDNA) mutations with aging in somatic cells has been implicated in mitochondrial dysfunction and linked to age-onset diseases in humans. Here, we asked if somatic mtDNA mutations are also associated with aging in the mouse. MtDNA integrity in multiple organs and tissues in young and old (2-34 months) wild type (wt) mice was investigated by whole genome sequencing. Remarkably, no acquired somatic mutations were detected in tested tissues. However, we identified several non-synonymous germline mtDNA variants whose heteroplasmy levels (ratio of normal to mutant mtDNA) increased significantly with aging suggesting clonal expansion of inherited mtDNA mutations. Polg mutator mice, a model for premature aging, exhibited both germline and somatic mtDNA mutations whose numbers and heteroplasmy levels increased significantly with age implicating involvement in premature aging. Our results suggest that, in contrast to humans, acquired somatic mtDNA mutations do not accompany the aging process in wt mice.
Collapse
Affiliation(s)
- Hong Ma
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Yeonmi Lee
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
- Stem Cell Center, ASAN Institute for Life Sciences, ASAN Medical Center, Seoul, South Korea
| | - Tomonari Hayama
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Crystal Van Dyken
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Nuria Marti-Gutierrez
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Ying Li
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Riffat Ahmed
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Amy Koski
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Eunju Kang
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
- Stem Cell Center, ASAN Institute for Life Sciences, ASAN Medical Center, Seoul, South Korea
| | - Hayley Darby
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Thanasup Gonmanee
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Younjung Park
- Stem Cell Center, ASAN Institute for Life Sciences, ASAN Medical Center, Seoul, South Korea
| | - Don P. Wolf
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
| | - Chong Jai Kim
- Stem Cell Center, ASAN Institute for Life Sciences, ASAN Medical Center, Seoul, South Korea
| | - Shoukhrat Mitalipov
- Center for Embryonic Cell and Gene Therapy, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Reproductive & Developmental Sciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, United States of America
| |
Collapse
|
116
|
Nissanka N, Bacman SR, Plastini MJ, Moraes CT. The mitochondrial DNA polymerase gamma degrades linear DNA fragments precluding the formation of deletions. Nat Commun 2018; 9:2491. [PMID: 29950568 PMCID: PMC6021392 DOI: 10.1038/s41467-018-04895-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 05/25/2018] [Indexed: 02/03/2023] Open
Abstract
Double-strand breaks in the mitochondrial DNA (mtDNA) result in the formation of linear fragments that are rapidly degraded. However, the identity of the nuclease(s) performing this function is not known. We found that the exonuclease function of the mtDNA polymerase gamma (POLG) is required for this rapid degradation of mtDNA fragments. POLG is recruited to linearized DNA fragments in an origin of replication-independent manner. Moreover, in the absence of POLG exonuclease activity, the prolonged existence of mtDNA linear fragments leads to increased levels of mtDNA deletions, which have been previously identified in the mutator mouse, patients with POLG mutations and normal aging. Mitochondrial DNA fragments are rapidly degraded when double strand breaks occur. Here the authors reveal that the exonuclease activity of polymerase gamma is important for efficient degradation of these fragments and to avoid formation of large deletions.
Collapse
Affiliation(s)
- Nadee Nissanka
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Sandra R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Melanie J Plastini
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Carlos T Moraes
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, 33136, USA. .,Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
| |
Collapse
|
117
|
Zinovkina LA. Mechanisms of Mitochondrial DNA Repair in Mammals. BIOCHEMISTRY (MOSCOW) 2018; 83:233-249. [PMID: 29625543 DOI: 10.1134/s0006297918030045] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Accumulation of mutations in mitochondrial DNA leads to the development of severe, currently untreatable diseases. The contribution of these mutations to aging and progress of neurodegenerative diseases is actively studied. Elucidation of DNA repair mechanisms in mitochondria is necessary for both developing approaches to the therapy of diseases caused by mitochondrial mutations and understanding specific features of mitochondrial genome functioning. Mitochondrial DNA repair systems have become a subject of extensive studies only in the last decade due to development of molecular biology methods. DNA repair systems of mammalian mitochondria appear to be more diverse and effective than it had been thought earlier. Even now, one may speak about the existence of mitochondrial mechanisms for the repair of single- and double-stranded DNA lesions. Homologous recombination also takes place in mammalian mitochondria, although its functional significance and molecular mechanisms remain obscure. In this review, I describe DNA repair systems in mammalian mitochondria, such as base excision repair (BER) and microhomology-mediated end joining (MMEJ) and discuss a possibility of existence of mitochondrial DNA repair mechanisms otherwise typical for the nuclear DNA, e.g., nucleotide excision repair (NER), mismatch repair (MMR), homologous recombination, and classical non-homologous end joining (NHEJ). I also present data on the mechanisms for coordination of the nuclear and mitochondrial DNA repair systems that have been actively studied recently.
Collapse
Affiliation(s)
- L A Zinovkina
- Lomonosov Moscow State University, Faculty of Bioengineering and Bioinformatics, Moscow, 119234, Russia.
| |
Collapse
|
118
|
Deyu H, Luqing C, Xianglian L, Pu G, Qirong L, Xu W, Zonghui Y. Protective mechanisms involving enhanced mitochondrial functions and mitophagy against T-2 toxin-induced toxicities in GH3 cells. Toxicol Lett 2018; 295:41-53. [PMID: 29870751 DOI: 10.1016/j.toxlet.2018.05.041] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 05/29/2018] [Accepted: 05/31/2018] [Indexed: 12/21/2022]
Abstract
T-2 toxin is the most toxic member of trichothecene mycotoxin. So far, the mechanism of mitochondrial toxicity and protective mechanism in mammalian cells against T-2 toxin are not fully understood. In this study, we aimed to investigate the cellular and mitochondrial toxicity of T-2 toxin, and the cellular protective mechanisms in rat pituitary GH3 cells. We showed that T-2 toxin significantly increased reactive oxygen species (ROS) and DNA damage and caused apoptosis in GH3 cells. T-2 toxin induced abnormal cell morphology, cytoplasm and nuclear shrinkage, nuclear fragmentation and formation of apoptotic bodies and autophagosomes. The mitochondrial degradative morphologies included local or total cristae collapse and small condensed mitochondria. T-2 toxin decreased the mitochondrial membrane potential. However, T-2 toxin significantly increased the superoxide dismutase (SOD) activity and expression of antioxidant genes glutathione peroxidase 1 (GPx-1), catalase (CAT), mitochondria-specific SOD-2 and mitochondrial uncoupling protein-1, -2 and -3 (UCP-1, 2 and 3). Interestingly, T-2 toxin increased adenosine triphosphate (ATP) levels and mitochondrial complex I activity, and increased the expression of most of mitochondrial electron transport chain subunits tested and critical transcription factors controlling mitochondrial biogenesis and mitochondrial DNA transcription and replication. T-2 toxin increased mitophagic activity by increasing the expression of mitophagy-specific proteins NIP-like protein X (NIX), PTEN-induced putative kinase protein 1 (PINK1) and E3 ubiquitin ligase Parkin. T-2 toxin activated the protective protein kinase A (PKA) signaling pathway, which activated the nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/PINK1/Parkin pathway to mediate mitophagy. Taken together, our results suggested that the mammalian cells could increase their resistance against T-2 toxin by increasing the antioxidant activity, mitophagy and mitochondrial function.
Collapse
Affiliation(s)
- Huang Deyu
- Department of Animal Sciences & Technology, Key Laboratory for the Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Cui Luqing
- Department of Animal Sciences & Technology, Laboratory of Quality & Safety Risk Assessment for Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Liu Xianglian
- Department of Animal Sciences & Technology, Laboratory of Quality & Safety Risk Assessment for Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Guo Pu
- Department of Animal Sciences & Technology, Laboratory of Quality & Safety Risk Assessment for Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Lu Qirong
- Department of Animal Sciences & Technology, Laboratory of Quality & Safety Risk Assessment for Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Wang Xu
- Department of Animal Sciences & Technology, Key Laboratory for the Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, 430070, China; Department of Animal Sciences & Technology, Laboratory of Quality & Safety Risk Assessment for Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
| | - Yuan Zonghui
- Department of Animal Sciences & Technology, Key Laboratory for the Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, 430070, China; Department of Animal Sciences & Technology, Laboratory of Quality & Safety Risk Assessment for Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
| |
Collapse
|
119
|
Mechta M, Ingerslev LR, Barrès R. Methodology for Accurate Detection of Mitochondrial DNA Methylation. J Vis Exp 2018:57772. [PMID: 29863674 PMCID: PMC6101301 DOI: 10.3791/57772] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Quantification of DNA methylation can be achieved using bisulfite sequencing, which takes advantage of the property of sodium bisulfite to convert unmethylated cytosine into uracil, in a single-stranded DNA context. Bisulfite sequencing can be targeted (using PCR) or performed on the whole genome and provides absolute quantification of cytosine methylation at the single base-resolution. Given the distinct nature of nuclear- and mitochondrial DNA, notably in the secondary structure, adaptions of bisulfite sequencing methods for investigating cytosine methylation in mtDNA should be made. Secondary and tertiary structure of mtDNA can indeed lead to bisulfite sequencing artifacts leading to false-positives due to incomplete denaturation poor access of bisulfite to single-stranded DNA. Here, we describe a protocol using an enzymatic digestion of DNA with BamHI coupled with bioinformatic analysis pipeline to allow accurate quantification of cytosine methylation levels in mtDNA. In addition, we provide guidelines for designing the bisulfite sequencing primers specific to mtDNA, in order to avoid targeting undesirable NUclear MiTochondrial segments (NUMTs) inserted into the nuclear genome.
Collapse
Affiliation(s)
- Mie Mechta
- The Novo Nordisk Foundation for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen
| | - Lars Roed Ingerslev
- The Novo Nordisk Foundation for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen
| | - Romain Barrès
- The Novo Nordisk Foundation for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen;
| |
Collapse
|
120
|
Franco DG, Moretti IF, Marie SKN. Mitochondria Transcription Factor A: A Putative Target for the Effect of Melatonin on U87MG Malignant Glioma Cell Line. Molecules 2018; 23:molecules23051129. [PMID: 29747444 PMCID: PMC6099566 DOI: 10.3390/molecules23051129] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/04/2018] [Accepted: 05/07/2018] [Indexed: 12/30/2022] Open
Abstract
The disruption of mitochondrial activity has been associated with cancer development because it contributes to regulating apoptosis and is the main source of reactive oxygen species (ROS) production. Mitochondrial transcription factor A (TFAM) is a protein that maintains mitochondrial DNA (mtDNA) integrity, and alterations in its expression are associated with mitochondrial damage and cancer development. In addition, studies have shown that mitochondria are a known target of melatonin, the pineal gland hormone that plays an important anti-tumorigenic role. Thus, we hypothesized that melatonin decreases the expression of TFAM (RNA and protein) in the human glioblastoma cell line U87MG, which disrupts mtDNA expression and results in cell death due to increased ROS production and mitochondrial damage. Our results confirm the hypothesis, and also show that melatonin reduced the expression of other mitochondrial transcription factors mRNA (TFB1M and TFB2M) and interfered with mtDNA transcription. Moreover, melatonin delayed cell cycle progression and potentiated the reduction of cell survival due to treatment with the chemotherapeutic agent temozolomide. In conclusion, elucidating the effect of melatonin on TFAM expression should help to understand the signaling pathways involved in glioblastoma progression, and melatonin could be potentially applied in the treatment of this type of brain tumor.
Collapse
Affiliation(s)
- Daiane G Franco
- Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP 01246903, Brazil.
| | - Isabele F Moretti
- Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP 01246903, Brazil.
| | - Suely K N Marie
- Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP 01246903, Brazil.
| |
Collapse
|
121
|
Kasahara T, Kato T. What Can Mitochondrial DNA Analysis Tell Us About Mood Disorders? Biol Psychiatry 2018; 83:731-738. [PMID: 29102411 DOI: 10.1016/j.biopsych.2017.09.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/11/2017] [Accepted: 09/12/2017] [Indexed: 12/11/2022]
Abstract
Variants in mitochondrial DNA (mtDNA) and nuclear genes encoding mitochondrial proteins in bipolar disorder, depression, or other psychiatric disorders have been studied for decades, since mitochondrial dysfunction was first suggested in the brains of patients with these diseases. Candidate gene association studies initially resulted in findings compatible with the mitochondrial dysfunction hypothesis. Many of those studies, however, were conducted with modest sample sizes (N < 1000), which could cause false positive findings. Furthermore, the DNA samples examined in these studies, including genome-wide association studies, were generally derived from peripheral tissues. One key unanswered question is whether there is an association between mood disorders and somatic mtDNA mutations (deletions and point mutations) in brain regions that accumulate a high amount of mtDNA mutations and/or are involved in the regulation of mood. Two lines of robust evidence supporting the importance of mtDNA mutations in brain tissues for mood disorders have come from clinical observation of mitochondrial disease patients who carry primary mtDNA mutations or accumulate secondary mtDNA mutations due to nuclear mutations and an animal model study. More than half of mitochondrial disease patients have comorbid mood disorders, and mice with neuron-specific accumulation of mtDNA mutations show spontaneous depression-like episodes. In this review, we first summarize the current knowledge of mtDNA and its genetics and discuss what mtDNA analysis tells us about neuropsychiatric disorders based on an example of Parkinson's disease. We also discuss challenges and future directions beyond mtDNA analysis toward an understanding of the pathophysiology of "idiopathic" mood disorders.
Collapse
Affiliation(s)
- Takaoki Kasahara
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako-shi, Saitama, Japan
| | - Tadafumi Kato
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, Wako-shi, Saitama, Japan.
| |
Collapse
|
122
|
DNA Methylation-a Potential Source of Mitochondria DNA Base Mismatch in the Development of Diabetic Retinopathy. Mol Neurobiol 2018; 56:88-101. [PMID: 29679259 DOI: 10.1007/s12035-018-1086-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 04/11/2018] [Indexed: 01/09/2023]
Abstract
In the development of diabetic retinopathy, retinal mitochondria are dysfunctional, and mitochondrial DNA (mtDNA) is damaged with increased base mismatches and hypermethylated cytosines. DNA methylation is also a potential source of mutation, and in diabetes, the noncoding region, the displacement loop (D-loop), experiences more methylation and base mismatches than other regions of the mtDNA. Our aim was to investigate a possible crosstalk between mtDNA methylation and base mismatches in the development of diabetic retinopathy. The effect of inhibition of Dnmts (by 5-aza-2'-deoxycytidine or Dnmt1-siRNA) on glucose-induced mtDNA base mismatches was investigated in human retinal endothelial cells by surveyor endonuclease digestion and validated by Sanger sequencing. The role of deamination factors on increased base mismatches was determined in the cells genetically modulated for mitochondrial superoxide dismutase (Sod2) or cytidine-deaminase (APOBEC3A). The results were confirmed in an in vivo model using retinal microvasculature from diabetic mice overexpressing Sod2. Inhibition of DNA methylation, or regulation of cytosine deamination, significantly inhibited an increase in base mismatches at the D-loop and prevented mitochondrial dysfunction. Overexpression of Sod2 in mice also prevented diabetes-induced D-loop hypermethylation and increase in base mismatches. The crosstalk between DNA methylation and base mismatches continued even after termination of hyperglycemia, suggesting its role in the metabolic memory phenomenon associated with the progression of diabetic retinopathy. Inhibition of DNA methylation limits the availability of methylated cytosine for deamination, suggesting a crosstalk between DNA methylation and base mismatches. Thus, regulation of DNA methylation, or its deamination, should impede the development of diabetic retinopathy by preventing formation of base mismatches and mitochondrial dysfunction.
Collapse
|
123
|
Hedberg A, Knutsen E, Løvhaugen AS, Jørgensen TE, Perander M, Johansen SD. Cancer-specific SNPs originate from low-level heteroplasmic variants in human mitochondrial genomes of a matched cell line pair. Mitochondrial DNA A DNA Mapp Seq Anal 2018; 30:82-91. [PMID: 29671673 DOI: 10.1080/24701394.2018.1461852] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Low-level mitochondrial heteroplasmy is a common phenomenon in both normal and cancer cells. Here, we investigate the link between low-level heteroplasmy and mitogenome mutations in a human breast cancer matched cell line by high-throughput sequencing. We identified 23 heteroplasmic sites, of which 15 were common between normal cells (Hs578Bst) and cancer cells (Hs578T). Most sites were clustered within the highly conserved Complex IV and ribosomal RNA genes. Two heteroplasmic variants in normal cells were found as fixed mutations in cancer cells. This indicates a positive selection of these variants in cancer cells. RNA-Seq analysis identified upregulated L-strand specific transcripts in cancer cells, which include three mitochondrial long non-coding RNA molecules. We hypothesize that this is due to two cancer cell-specific mutations in the control region.
Collapse
Affiliation(s)
- Annica Hedberg
- a Department of Medical Biology, Faculty of Health Sciences , UiT - The Arctic University of Norway , Tromsø , Norway
| | - Erik Knutsen
- a Department of Medical Biology, Faculty of Health Sciences , UiT - The Arctic University of Norway , Tromsø , Norway
| | - Anne Silje Løvhaugen
- a Department of Medical Biology, Faculty of Health Sciences , UiT - The Arctic University of Norway , Tromsø , Norway
| | - Tor Erik Jørgensen
- b Genomics Group, Faculty of Biosciences and Aquaculture , Nord University , Bodø , Norway
| | - Maria Perander
- a Department of Medical Biology, Faculty of Health Sciences , UiT - The Arctic University of Norway , Tromsø , Norway
| | - Steinar D Johansen
- a Department of Medical Biology, Faculty of Health Sciences , UiT - The Arctic University of Norway , Tromsø , Norway.,b Genomics Group, Faculty of Biosciences and Aquaculture , Nord University , Bodø , Norway
| |
Collapse
|
124
|
Wiehe RS, Gole B, Chatre L, Walther P, Calzia E, Ricchetti M, Wiesmüller L. Endonuclease G promotes mitochondrial genome cleavage and replication. Oncotarget 2018; 9:18309-18326. [PMID: 29719607 PMCID: PMC5915074 DOI: 10.18632/oncotarget.24822] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 03/12/2018] [Indexed: 12/26/2022] Open
Abstract
Endonuclease G (EndoG) is a nuclear-encoded endonuclease, mostly localised in mitochondria. In the nucleus EndoG participates in site-specific cleavage during replication stress and genome-wide DNA degradation during apoptosis. However, the impact of EndoG on mitochondrial DNA (mtDNA) metabolism is poorly understood. Here, we investigated whether EndoG is involved in the regulation of mtDNA replication and removal of aberrant copies. We applied the single-cell mitochondrial Transcription and Replication Imaging Protocol (mTRIP) and PCR-based strategies on human cells after knockdown/knockout and re-expression of EndoG. Our analysis revealed that EndoG stimulates both mtDNA replication initiation and mtDNA depletion, the two events being interlinked and dependent on EndoG's nuclease activity. Stimulation of mtDNA replication by EndoG was independent of 7S DNA processing at the replication origin. Importantly, both mtDNA-directed activities of EndoG were promoted by oxidative stress. Inhibition of base excision repair (BER) that repairs oxidative stress-induced DNA damage unveiled a pronounced effect of EndoG on mtDNA removal, reminiscent of recently discovered links between EndoG and BER in the nucleus. Altogether with the downstream effects on mitochondrial transcription, protein expression, redox status and morphology, this study demonstrates that removal of damaged mtDNA by EndoG and compensatory replication play a critical role in mitochondria homeostasis.
Collapse
Affiliation(s)
| | - Boris Gole
- Department of Obstetrics and Gynecology, Ulm University, Ulm, 89075, Germany
- Present address: Centre for Human Molecular Genetics and Pharmacogenomics, Medical Faculty, University of Maribor, Maribor, SI-2000, Slovenia
| | - Laurent Chatre
- Department of Developmental and Stem Cell Biology, Institute Pasteur, Stem Cells and Development, 75724 Cedex 15, Paris, France
- Team Stability of Nuclear and Mitochondrial DNA, Unit of Stem Cells and Development, CNRS UMR 3738, 75724 Cedex 15, Paris, France
| | - Paul Walther
- Central Facility for Electron Microscopy, Ulm University, Ulm, 89081, Germany
| | - Enrico Calzia
- Institute of Anesthesiological Pathophysiology and Process Engineering, Ulm University Hospital, Ulm, 89081, Germany
| | - Miria Ricchetti
- Department of Developmental and Stem Cell Biology, Institute Pasteur, Stem Cells and Development, 75724 Cedex 15, Paris, France
- Team Stability of Nuclear and Mitochondrial DNA, Unit of Stem Cells and Development, CNRS UMR 3738, 75724 Cedex 15, Paris, France
| | - Lisa Wiesmüller
- Department of Obstetrics and Gynecology, Ulm University, Ulm, 89075, Germany
| |
Collapse
|
125
|
Ferreira N, Rackham O, Filipovska A. Regulation of a minimal transcriptome by repeat domain proteins. Semin Cell Dev Biol 2018; 76:132-141. [DOI: 10.1016/j.semcdb.2017.08.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/15/2017] [Accepted: 08/18/2017] [Indexed: 01/19/2023]
|
126
|
The complete mitogenome of Pelochelys cantorii (Guangning) and the comparative analysis of different habitats. CONSERV GENET RESOUR 2018. [DOI: 10.1007/s12686-017-0752-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
127
|
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.
Collapse
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
| |
Collapse
|
128
|
Kuang Y, Sechi M, Nurra S, Ljungman M, Neamati N. Design and Synthesis of Novel Reactive Oxygen Species Inducers for the Treatment of Pancreatic Ductal Adenocarcinoma. J Med Chem 2018; 61:1576-1594. [PMID: 29328656 DOI: 10.1021/acs.jmedchem.7b01463] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Altering redox homeostasis provides distinctive therapeutic opportunities for the treatment of pancreatic cancer. Quinazolinediones (QDs) are novel redox modulators that we previously showed to induce potent growth inhibition in pancreatic ductal adenocarcinoma (PDAC) cell lines. Our lead optimization campaign yielded QD325 as the most potent redox modulator candidate inducing substantial reactive oxygen species (ROS) in PDAC cells. Nascent RNA sequencing following treatments with the QD compounds revealed induction of stress responses in nucleus, endoplasmic reticulum, and mitochondria of pancreatic cancer cells. Furthermore, the QD compounds induced Nrf2-mediated oxidative stress and unfolded protein responses as demonstrated by dose-dependent increases in RNA synthesis of representative genes such as NQO1, HMOX1, DDIT3, and HSPA5. At higher concentrations, the QDs blocked mitochondrial function by inhibiting mtDNA transcription and downregulating the mtDNA-encoded OXPHOS enzymes. Importantly, treatments with QD325 were well tolerated in vivo and significantly delayed tumor growth in mice. Our study supports the development of QD325 as a new therapeutic in the treatment of PDAC.
Collapse
Affiliation(s)
- Yuting Kuang
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan , 1600 Huron Parkway, Ann Arbor, Michigan 48109, United States.,Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California , 1985 Zonal Avenue, Los Angeles, California 90033, United States
| | - Mario Sechi
- Department of Chemistry and Pharmacy, University of Sassari , Via Vienna 2, 07100 Sassari, Italy
| | - Salvatore Nurra
- Department of Chemistry and Pharmacy, University of Sassari , Via Vienna 2, 07100 Sassari, Italy
| | - Mats Ljungman
- Department of Radiation Oncology, University of Michigan , 1600 Huron Parkway, Ann Arbor, Michigan 48109, United States
| | - Nouri Neamati
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan , 1600 Huron Parkway, Ann Arbor, Michigan 48109, United States
| |
Collapse
|
129
|
Floros VI, Pyle A, Dietmann S, Wei W, Tang WCW, Irie N, Payne B, Capalbo A, Noli L, Coxhead J, Hudson G, Crosier M, Strahl H, Khalaf Y, Saitou M, Ilic D, Surani MA, Chinnery PF. Segregation of mitochondrial DNA heteroplasmy through a developmental genetic bottleneck in human embryos. Nat Cell Biol 2018; 20:144-151. [PMID: 29335530 PMCID: PMC6551220 DOI: 10.1038/s41556-017-0017-8] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 11/27/2017] [Indexed: 12/13/2022]
Abstract
Mitochondrial DNA (mtDNA) mutations cause inherited diseases and are implicated in the pathogenesis of common late-onset disorders, but how they arise is not clear1,2. Here we show that mtDNA mutations are present in primordial germ cells (PGCs) within healthy female human embryos. Isolated PGCs have a profound reduction in mtDNA content, with discrete mitochondria containing ~5 mtDNA molecules. Single-cell deep mtDNA sequencing of in vivo human female PGCs showed rare variants reaching higher heteroplasmy levels in late PGCs, consistent with the observed genetic bottleneck. We also saw the signature of selection against non-synonymous protein-coding, tRNA gene and D-loop variants, concomitant with a progressive upregulation of genes involving mtDNA replication and transcription, and linked to a transition from glycolytic to oxidative metabolism. The associated metabolic shift would expose deleterious mutations to selection during early germ cell development, preventing the relentless accumulation of mtDNA mutations in the human population predicted by Muller's ratchet. Mutations escaping this mechanism will show shifts in heteroplasmy levels within one human generation, explaining the extreme phenotypic variation seen in human pedigrees with inherited mtDNA disorders.
Collapse
Affiliation(s)
- Vasileios I Floros
- MRC-Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
- Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Angela Pyle
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Sabine Dietmann
- Wellcome Trust-Medical Research Council Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Wei Wei
- MRC-Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
- Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - Walfred C W Tang
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, UK
| | - Naoko Irie
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, UK
| | - Brendan Payne
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Antonio Capalbo
- GENERA, Centre for Reproductive Medicine, Clinica Valle Giulia, Rome, Italy
- GENETYX, Reproductive Genetics Laboratory, Marostica, Italy
| | - Laila Noli
- Division of Women's Health, Faculty of Life Sciences and Medicine, King's College London, London, UK
- Assisted Conception Unit, Guy's Hospital, London, UK
| | - Jonathan Coxhead
- Genomic Core Facility, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Gavin Hudson
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Moira Crosier
- Human Developmental Biology Resource, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Henrik Strahl
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Yacoub Khalaf
- Division of Women's Health, Faculty of Life Sciences and Medicine, King's College London, London, UK
- Assisted Conception Unit, Guy's Hospital, London, UK
| | - Mitinori Saitou
- Department of Anatomy and Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- JST, ERATO, Kyoto, Japan
| | - Dusko Ilic
- Division of Women's Health, Faculty of Life Sciences and Medicine, King's College London, London, UK
- Assisted Conception Unit, Guy's Hospital, London, UK
| | - M Azim Surani
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, UK
| | - Patrick F Chinnery
- MRC-Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
- Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK.
| |
Collapse
|
130
|
Abstract
Mitochondrial DNA (mtDNA), which is essential for mitochondrial and cell function, is replicated and transcribed in the organelle by proteins that are entirely coded in the nucleus. Replication of mtDNA is challenged not only by threats related to the replication machinery and orchestration of DNA synthesis, but also by factors linked to the peculiarity of this genome. Indeed the architecture, organization, copy number, and location of mtDNA, which are markedly distinct from the nuclear genome, require ad hoc and complex regulation to ensure coordinated replication. As a consequence sub-optimal mtDNA replication, which results from compromised regulation of these factors, is generally associated with mitochondrial dysfunction and disease. Mitochondrial DNA replication should be considered in the context of the organelle and the whole cell, and not just a single genome or a single replication event. Major threats to mtDNA replication are linked to its dependence on both mitochondrial and nuclear factors, which require exquisite coordination of these crucial subcellular compartments. Moreover, regulation of replication events deals with a dynamic population of multiple mtDNA molecules rather than with a fixed number of genome copies, as it is the case for nuclear DNA. Importantly, the mechanistic aspects of mtDNA replication are still debated. We describe here major challenges for human mtDNA replication, the mechanistic aspects of the process that are to a large extent original, and their consequences on disease.
Collapse
Affiliation(s)
- Miria Ricchetti
- Institut Pasteur, Department of Developmental and Stem Cell Biology, Stem Cells and Development, 75724 Cedex15, Paris, France; Team Stability of Nuclear and Mitochondrial DNA, CNRS UMR 3738, 75724, Cedex15, Paris, France.
| |
Collapse
|
131
|
RAD51C/XRCC3 Facilitates Mitochondrial DNA Replication and Maintains Integrity of the Mitochondrial Genome. Mol Cell Biol 2018; 38:MCB.00489-17. [PMID: 29158291 DOI: 10.1128/mcb.00489-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 11/10/2017] [Indexed: 12/12/2022] Open
Abstract
Mechanisms underlying mitochondrial genome maintenance have recently gained wide attention, as mutations in mitochondrial DNA (mtDNA) lead to inherited muscular and neurological diseases, which are linked to aging and cancer. It was previously reported that human RAD51, RAD51C, and XRCC3 localize to mitochondria upon oxidative stress and are required for the maintenance of mtDNA stability. Since RAD51 and RAD51 paralogs are spontaneously imported into mitochondria, their precise role in mtDNA maintenance under unperturbed conditions remains elusive. Here, we show that RAD51C/XRCC3 is an additional component of the mitochondrial nucleoid having nucleus-independent roles in mtDNA maintenance. RAD51C/XRCC3 localizes to the mtDNA regulatory regions in the D-loop along with the mitochondrial polymerase POLG, and this recruitment is dependent upon Twinkle helicase. Moreover, upon replication stress, RAD51C and XRCC3 are further enriched at the mtDNA mutation hot spot region D310. Notably, the absence of RAD51C/XRCC3 affects the stability of POLG on mtDNA. As a consequence, RAD51C/XRCC3-deficient cells exhibit reduced mtDNA synthesis and increased lesions in the mitochondrial genome, leading to overall unhealthy mitochondria. Together, these findings lead to the proposal of a mechanism for a direct role of RAD51C/XRCC3 in maintaining mtDNA integrity under replication stress conditions.
Collapse
|
132
|
Herbers E, Kekäläinen NJ, Hangas A, Pohjoismäki JL, Goffart S. Tissue specific differences in mitochondrial DNA maintenance and expression. Mitochondrion 2018; 44:85-92. [PMID: 29339192 DOI: 10.1016/j.mito.2018.01.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 01/05/2018] [Accepted: 01/11/2018] [Indexed: 01/17/2023]
Abstract
The different cell types of multicellular organisms have specialized physiological requirements, affecting also their mitochondrial energy production and metabolism. The genome of mitochondria is essential for mitochondrial oxidative phosphorylation (OXHPOS) and thus plays a central role in many human mitochondrial pathologies. Disorders affecting mitochondrial DNA (mtDNA) maintenance are typically resulting in a tissue-specific pattern of mtDNA deletions and rearrangements. Despite this role in disease as well as a biomarker of mitochondrial biogenesis, the tissue-specific parameters of mitochondrial DNA maintenance have been virtually unexplored. In the presented study, we investigated mtDNA replication, topology, gene expression and damage in six different tissues of adult mice and sought to correlate these with the levels of known protein factors involved in mtDNA replication and transcription. Our results show that while liver and kidney cells replicate their mtDNA using the asynchronous mechanism known from cultured cells, tissues with high OXPHOS activity, such as heart, brain, skeletal muscle and brown fat, employ a strand-coupled replication mode, combined with increased levels of recombination. The strand-coupled replication mode correlated also with mtDNA damage levels, indicating that the replication mechanism represents a tissue-specific strategy to deal with intrinsic oxidative stress. While the preferred replication mode did not correlate with mtDNA transcription or the levels of most known mtDNA maintenance proteins, mtSSB was most abundant in tissues using strand-asynchronous mechanism. Although mitochondrial transcripts were most abundant in tissues with high metabolic rate, the mtDNA copy number per tissue mass was remarkably similar in all tissues. We propose that the tissue-specific features of mtDNA maintenance are primarily driven by the intrinsic reactive oxygen species exposure, mediated by DNA repair factors, whose identity remains to be elucidated.
Collapse
Affiliation(s)
- Elena Herbers
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI 80101, Joensuu, Finland
| | - Nina J Kekäläinen
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI 80101, Joensuu, Finland
| | - Anu Hangas
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI 80101, Joensuu, Finland
| | - Jaakko L Pohjoismäki
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI 80101, Joensuu, Finland
| | - Steffi Goffart
- Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI 80101, Joensuu, Finland.
| |
Collapse
|
133
|
Nissanka N, Moraes CT. Mitochondrial DNA damage and reactive oxygen species in neurodegenerative disease. FEBS Lett 2018; 592:728-742. [PMID: 29281123 DOI: 10.1002/1873-3468.12956] [Citation(s) in RCA: 252] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 12/06/2017] [Accepted: 12/19/2017] [Indexed: 12/12/2022]
Abstract
Mitochondria are essential organelles within the cell where most ATP is produced through oxidative phosphorylation (OXPHOS). A subset of the genes needed for this process are encoded by the mitochondrial DNA (mtDNA). One consequence of OXPHOS is the production of mitochondrial reactive oxygen species (ROS), whose role in mediating cellular damage, particularly in damaging mtDNA during ageing, has been controversial. There are subsets of neurons that appear to be more sensitive to ROS-induced damage, and mitochondrial dysfunction has been associated with several neurodegenerative disorders. In this review, we will discuss the current knowledge in the field of mtDNA and neurodegeneration, the debate about ROS as a pathological or beneficial contributor to neuronal function, bona fide mtDNA diseases, and insights from mouse models of mtDNA defects affecting the central nervous system.
Collapse
Affiliation(s)
- Nadee Nissanka
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, FL, USA
| | - Carlos T Moraes
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, FL, USA.,Department of Neurology, University of Miami Miller School of Medicine, FL, USA
| |
Collapse
|
134
|
Morphological and molecular variations induce mitochondrial dysfunction as a possible underlying mechanism of athletic amenorrhea. Exp Ther Med 2018; 15:993-998. [PMID: 29403550 DOI: 10.3892/etm.2017.5469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 09/05/2017] [Indexed: 11/05/2022] Open
Abstract
Female athletes may experience difficulties in achieving pregnancy due to athletic amenorrhea (AA); however, the underlying mechanisms of AA remain unknown. The present study focuses on the mitochondrial alteration and its function in detecting the possible mechanism of AA. An AA rat model was established by excessive swimming. Hematoxylin and eosin staining, and transmission electron microscopic methods were performed to evaluate the morphological changes of the ovary, immunohistochemical examinations and radioimmunoassays were used to detect the reproductive hormones and corresponding receptors. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to test the mtDNA copy number. PCR and western blot analysis were used to test the expression of ND2. The change of morphological features of the rat ovaries revealed evident abnormalities. Particularly, the features of the mitochondria were markedly altered. In addition, reproductive hormones in the serum and tissues of AA rats were also detected to evaluate the function of the ovaries, and the levels of these hormones were significantly decreased. Furthermore, the mitochondrial DNA copy number (mtDNA) and expression of NADH dehydrogenase subunit 2 (ND2) were quantitated by qPCR or western blot analysis. Accordingly, the mtDNA copy number and expression of ND2 expression were markedly reduced in the AA rats. In conclusion, mitochondrial dysfunction in AA may affect the cellular energy supply and, therefore, result in dysfunction of the ovary. Thus, mitochondrial dysfunction may be considered as a possible underlying mechanism for the occurrence of AA.
Collapse
|
135
|
Hauck L, Stanley-Hasnain S, Fung A, Grothe D, Rao V, Mak TW, Billia F. Cardiac-specific ablation of the E3 ubiquitin ligase Mdm2 leads to oxidative stress, broad mitochondrial deficiency and early death. PLoS One 2017; 12:e0189861. [PMID: 29267372 PMCID: PMC5739440 DOI: 10.1371/journal.pone.0189861] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 12/04/2017] [Indexed: 12/15/2022] Open
Abstract
The maintenance of normal heart function requires proper control of protein turnover. The ubiquitin-proteasome system is a principal regulator of protein degradation. Mdm2 is the main E3 ubiquitin ligase for p53 in mitotic cells thereby regulating cellular growth, DNA repair, oxidative stress and apoptosis. However, which of these Mdm2-related activities are preserved in differentiated cardiomyocytes has yet to be determined. We sought to elucidate the role of Mdm2 in the control of normal heart function. We observed markedly reduced Mdm2 mRNA levels accompanied by highly elevated p53 protein expression in the hearts of wild type mice subjected to myocardial infarction or trans-aortic banding. Accordingly, we generated conditional cardiac-specific Mdm2 gene knockout (Mdm2f/f;mcm) mice. In adulthood, Mdm2f/f;mcm mice developed spontaneous cardiac hypertrophy, left ventricular dysfunction with early mortality post-tamoxifen. A decreased polyubiquitination of myocardial p53 was observed, leading to its stabilization and activation, in the absence of acute stress. In addition, transcriptomic analysis of Mdm2-deficient hearts revealed that there is an induction of E2f1 and c-Myc mRNA levels with reduced expression of the Pgc-1a/Ppara/Esrrb/g axis and Pink1. This was associated with a significant degree of cardiomyocyte apoptosis, and an inhibition of redox homeostasis and mitochondrial bioenergetics. All these processes are early, Mdm2-associated events and contribute to the development of pathological hypertrophy. Our genetic and biochemical data support a role for Mdm2 in cardiac growth control through the regulation of p53, the Pgc-1 family of transcriptional coactivators and the pivotal antioxidant Pink1.
Collapse
Affiliation(s)
- Ludger Hauck
- Toronto General Research Institute, Toronto, Ontario, Canada
| | | | - Amelia Fung
- Toronto General Research Institute, Toronto, Ontario, Canada
| | - Daniela Grothe
- Toronto General Research Institute, Toronto, Ontario, Canada
| | - Vivek Rao
- Division of Cardiovascular Surgery, UHN, Toronto, Ontario, Canada
| | - Tak W. Mak
- Campbell Family Cancer Research Institute, Princess Margaret Hospital, Toronto, Ontario, Canada
| | - Filio Billia
- Toronto General Research Institute, Toronto, Ontario, Canada
- Division of Cardiology, University Health Network (UHN), Toronto, Ontario, Canada
- Heart and Stroke Richard Lewar Centre of Excellence, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario Canada
- * E-mail:
| |
Collapse
|
136
|
Differential Alterations of the Mitochondrial Morphology and Respiratory Chain Complexes during Postnatal Development of the Mouse Lung. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:9169146. [PMID: 29430286 PMCID: PMC5753018 DOI: 10.1155/2017/9169146] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 09/28/2017] [Indexed: 11/18/2022]
Abstract
Mitochondrial biogenesis and adequate energy production in various organs of mammals are necessary for postnatal adaptation to extrauterine life in an environment with high oxygen content. Even though transgenic mice are frequently used as experimental models, to date, no combined detailed molecular and morphological analysis on the mitochondrial compartment in different lung cell types has been performed during postnatal mouse lung development. In our study, we revealed a significant upregulation of most mitochondrial respiratory complexes at protein and mRNA levels in the lungs of P15 and adult animals in comparison to newborns. The majority of adult animal samples showed the strongest increase, except for succinate dehydrogenase protein (SDHD). Likewise, an increase in mRNA expression for mtDNA transcription machinery genes (Polrmt, Tfam, Tfb1m, and Tfb2m), mitochondrially encoded RNA (mt-Rnr1 and mt-Rnr2), and the nuclear-encoded mitochondrial DNA polymerase (POLG) was observed. The biochemical and molecular results were corroborated by a parallel increase of mitochondrial number, size, cristae number, and complexity, exhibiting heterogeneous patterns in distinct bronchiolar and alveolar epithelial cells. Taken together, our results suggest a specific adaptation and differential maturation of the mitochondrial compartment according to the metabolic needs of individual cell types during postnatal development of the mouse lung.
Collapse
|
137
|
Stoll EA, Karapavlovic N, Rosa H, Woodmass M, Rygiel K, White K, Turnbull DM, Faulkes CG. Naked mole-rats maintain healthy skeletal muscle and Complex IV mitochondrial enzyme function into old age. Aging (Albany NY) 2017; 8:3468-3485. [PMID: 27997359 PMCID: PMC5270680 DOI: 10.18632/aging.101140] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 12/02/2016] [Indexed: 12/15/2022]
Abstract
The naked mole-rat (NMR) Heterocephalus glaber is an exceptionally long-lived rodent, living up to 32 years in captivity. This extended lifespan is accompanied by a phenotype of negligible senescence, a phenomenon of very slow changes in the expected physiological characteristics with age. One of the many consequences of normal aging in mammals is the devastating and progressive loss of skeletal muscle, termed sarcopenia, caused in part by respiratory enzyme dysfunction within the mitochondria of skeletal muscle fibers. Here we report that NMRs avoid sarcopenia for decades. Muscle fiber integrity and mitochondrial ultrastructure are largely maintained in aged animals. While mitochondrial Complex IV expression and activity remains stable, Complex I expression is significantly decreased. We show that aged naked mole-rat skeletal muscle tissue contains some mitochondrial DNA rearrangements, although the common mitochondrial DNA deletions associated with aging in human and other rodent skeletal muscles are not present. Interestingly, NMR skeletal muscle fibers demonstrate a significant increase in mitochondrial DNA copy number. These results have intriguing implications for the role of mitochondria in aging, suggesting Complex IV, but not Complex I, function is maintained in the long-lived naked mole rat, where sarcopenia is avoided and healthy muscle function is maintained for decades.
Collapse
Affiliation(s)
- Elizabeth A Stoll
- LLHW Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.,Wellcome Trust Centre for Mitochondrial Research, Institute of Ageing and Health, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.,Institute for Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Nevena Karapavlovic
- Undergraduate Programme in Biomedical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Hannah Rosa
- LLHW Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.,Wellcome Trust Centre for Mitochondrial Research, Institute of Ageing and Health, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.,Institute for Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Michael Woodmass
- Undergraduate Programme in Biomedical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Karolina Rygiel
- LLHW Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.,Wellcome Trust Centre for Mitochondrial Research, Institute of Ageing and Health, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.,Institute for Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Kathryn White
- Electron Microscopy Research Services, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Douglass M Turnbull
- LLHW Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.,Wellcome Trust Centre for Mitochondrial Research, Institute of Ageing and Health, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.,Institute for Neuroscience, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Chris G Faulkes
- School of Biological & Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| |
Collapse
|
138
|
Li X, Xiong X, Zhang M, Wang K, Chen Y, Zhou J, Mao Y, Lv J, Yi D, Chen XW, Wang C, Qian SB, Yi C. Base-Resolution Mapping Reveals Distinct m 1A Methylome in Nuclear- and Mitochondrial-Encoded Transcripts. Mol Cell 2017; 68:993-1005.e9. [PMID: 29107537 DOI: 10.1016/j.molcel.2017.10.019] [Citation(s) in RCA: 297] [Impact Index Per Article: 42.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/26/2017] [Accepted: 10/18/2017] [Indexed: 12/17/2022]
Abstract
Gene expression can be post-transcriptionally regulated via dynamic and reversible RNA modifications. N1-methyladenosine (m1A) is a recently identified mRNA modification; however, little is known about its precise location and biogenesis. Here, we develop a base-resolution m1A profiling method, based on m1A-induced misincorporation during reverse transcription, and report distinct classes of m1A methylome in the human transcriptome. m1A in 5' UTR, particularly those at the mRNA cap, associate with increased translation efficiency. A different, small subset of m1A exhibit a GUUCRA tRNA-like motif, are evenly distributed in the transcriptome, and are dependent on the methyltransferase TRMT6/61A. Additionally, we show that m1A is prevalent in the mitochondrial-encoded transcripts. Manipulation of m1A level via TRMT61B, a mitochondria-localizing m1A methyltransferase, demonstrates that m1A in mitochondrial mRNA interferes with translation. Collectively, our approaches reveal distinct classes of m1A methylome and provide a resource for functional studies of m1A-mediated epitranscriptomic regulation.
Collapse
Affiliation(s)
- Xiaoyu Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Xushen Xiong
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Meiling Zhang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Kun Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Ying Chen
- Department of Chemical Biology and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Jun Zhou
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Yuanhui Mao
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Jia Lv
- Institute of Molecular Medicine, Peking University, Beijing 100871, China
| | - Danyang Yi
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Xiao-Wei Chen
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Institute of Molecular Medicine, Peking University, Beijing 100871, China
| | - Chu Wang
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; Department of Chemical Biology and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Shu-Bing Qian
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Chengqi Yi
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China; Department of Chemical Biology and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
| |
Collapse
|
139
|
Lee YK, Lim JJ, Jeoun UW, Min S, Lee EB, Kwon SM, Lee C, Yoon G. Lactate-mediated mitoribosomal defects impair mitochondrial oxidative phosphorylation and promote hepatoma cell invasiveness. J Biol Chem 2017; 292:20208-20217. [PMID: 28978646 DOI: 10.1074/jbc.m117.809012] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/29/2017] [Indexed: 12/30/2022] Open
Abstract
Impaired mitochondrial oxidative phosphorylation (OXPHOS) capacity, accompanied by enhanced glycolysis, is a key metabolic feature of cancer cells, but its underlying mechanism remains unclear. Previously, we reported that human hepatoma cells that harbor OXPHOS defects exhibit high tumor cell invasiveness via elevated claudin-1 (CLN1). In the present study, we show that OXPHOS-defective hepatoma cells (SNU354 and SNU423 cell lines) exhibit reduced expression of mitochondrial ribosomal protein L13 (MRPL13), a mitochondrial ribosome (mitoribosome) subunit, suggesting a ribosomal defect. Specific inhibition of mitoribosomal translation by doxycycline, chloramphenicol, or siRNA-mediated MRPL13 knockdown decreased mitochondrial protein expression, reduced oxygen consumption rate, and increased CLN1-mediated tumor cell invasiveness in SNU387 cells, which have active mitochondria. Interestingly, we also found that exogenous lactate treatment suppressed MRPL13 expression and oxygen consumption rate and induced CLN1 expression. A bioinformatic analysis of the open RNA-Seq database from The Cancer Genome Atlas (TCGA) liver hepatocellular carcinoma (LIHC) cohort revealed a significant negative correlation between MRPL13 and CLN1 expression. Moreover, in patients with low MRPL13 expression, two oxidative metabolic indicators, pyruvate dehydrogenase B expression and the ratio of lactate dehydrogenase type B to type A, significantly and negatively correlated with CLN1 expression, indicating that the combination of elevated glycolysis and deficient MRPL13 activity was closely linked to CLN1-mediated tumor activity in LIHC. These results suggest that OXPHOS defects may be initiated and propagated by lactate-mediated mitoribosomal deficiencies and that these deficiencies are critically involved in LIHC development.
Collapse
Affiliation(s)
| | - Jin J Lim
- Departments of Biochemistry, Suwon 16499, Korea
| | - Un-Woo Jeoun
- Departments of Biochemistry, Suwon 16499, Korea; Biomedical Sciences, Ajou University School of Medicine, Suwon 16499, Korea
| | - Seongki Min
- Departments of Biochemistry, Suwon 16499, Korea; Biomedical Sciences, Ajou University School of Medicine, Suwon 16499, Korea
| | - Eun-Beom Lee
- Departments of Biochemistry, Suwon 16499, Korea; Biomedical Sciences, Ajou University School of Medicine, Suwon 16499, Korea
| | - So Mee Kwon
- Departments of Biochemistry, Suwon 16499, Korea
| | - Changhan Lee
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California 90089
| | - Gyesoon Yoon
- Departments of Biochemistry, Suwon 16499, Korea; Biomedical Sciences, Ajou University School of Medicine, Suwon 16499, Korea.
| |
Collapse
|
140
|
Wang D, Li GD, Fan Y, Zhang DF, Bi R, Yu XF, Long H, Li YY, Yao YG. The mtDNA replication-related genes TFAM and POLG are associated with leprosy in Han Chinese from Southwest China. J Dermatol Sci 2017; 88:349-356. [PMID: 28958595 DOI: 10.1016/j.jdermsci.2017.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 09/07/2017] [Accepted: 09/13/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND The pathogen Mycobacterium leprae of leprosy is heavily dependent on the host energy metabolites and nutritional products for survival. Previously we and others have identified associations of several mitochondrion-related genes and mitochondrial DNA (mtDNA) copy number alterations with leprosy and/or its subtype. We hypothesized that genetic variants of mtDNA replication-related genes would affect leprosy. OBJECTIVE We aimed to identify genetic associations between the mtDNA replication-related genes TFAM, POLG and leprosy. METHODS Genetic association study was performed in 2898 individuals from two independent sample sets in Yunnan Province, China. We first screened 7 tag SNPs of TFAM and POLG in 527 leprosy cases and 583 controls (Sample I). Expression quantitative trait loci (eQTL) analysis and differential mRNA expression were analyzed to discern potential effect of risk variants. The entire exon region of TFAM and POLG were further analyzed in 798 leprosy cases and 990 controls (Sample II; 4327 East Asians from the ExAC dataset was included as a reference control) by using targeted gene sequencing for fine mapping potentially causal variants. RESULTS Two tag SNPs of TFAM (rs1049432, P=0.007) and POLG (rs3176238, P=0.006) were associated with multibacillary leprosy (MB) in Sample I and the significance survived correction for multiple comparisons. SNPs rs1937 of TFAM (which was linked with rs1049432) and rs61756401 of POLG were associated with leprosy, whereas no potentially causative coding variants were identified in Sample II. The eQTL analysis showed that rs1049432 was a significant cis eQTL for TFAM in nerve tissue (P=1.20×10-12), and rs3176238 was a significant cis eQTL for POLG in nerve (P=3.90×10-13) and skin tissues (P=2.50×10-11). Consistently, mRNA level of POLG was differentially expressed in leprotic skin lesions. CONCLUSIONS Genetic variants of TFAM and POLG were associated with leprosy in Han Chinese, presumably by affecting gene expression.
Collapse
Affiliation(s)
- Dong Wang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, 650223, China
| | - Guo-Dong Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, 650223, China; Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Yu Fan
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, 650223, China
| | - Deng-Feng Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, 650223, China
| | - Rui Bi
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, 650223, China
| | - Xiu-Feng Yu
- Wenshan Institute of Dermatology, Wenshan, Yunnan, 663000, China
| | - Heng Long
- Wenshan Institute of Dermatology, Wenshan, Yunnan, 663000, China
| | - Yu-Ye Li
- Department of Dermatology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| | - Yong-Gang Yao
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, 650223, China; Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
| |
Collapse
|
141
|
Lee SR, Han J. Mitochondrial Mutations in Cardiac Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:81-111. [PMID: 28551783 DOI: 10.1007/978-3-319-55330-6_5] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mitochondria individually encapsulate their own genome, unlike other cellular organelles. Mitochondrial DNA (mtDNA) is a circular, double-stranded, 16,569-base paired DNA containing 37 genes: 13 proteins of the mitochondrial respiratory chain, two ribosomal RNAs (rRNAs; 12S and 16S), and 22 transfer RNAs (tRNAs). The mtDNA is more vulnerable to oxidative modifications compared to nuclear DNA because of its proximity to ROS-producing sites, limited presence of DNA damage repair systems, and continuous replication in the cell. mtDNA mutations can be inherited or sporadic. Simple mtDNA mutations are point mutations, which are frequently found in mitochondrial tRNA loci, causing mischarging of mitochondrial tRNAs or deletion, duplication, or reduction in mtDNA content. Because mtDNA has multiple copies and a specific replication mechanism in cells or tissues, it can be heterogenous, resulting in characteristic phenotypic presentations such as heteroplasmy, genetic drift, and threshold effects. Recent studies have increased the understanding of basic mitochondrial genetics, providing an insight into the correlations between mitochondrial mutations and cardiac manifestations including hypertrophic or dilated cardiomyopathy, arrhythmia, autonomic nervous system dysfunction, heart failure, or sudden cardiac death with a syndromic or non-syndromic phenotype. Clinical manifestations of mitochondrial mutations, which result from structural defects, functional impairment, or both, are increasingly detected but are not clear because of the complex interplay between the mitochondrial and nuclear genomes, even in homoplasmic mitochondrial populations. Additionally, various factors such as individual susceptibility, nutritional state, and exposure to chemicals can influence phenotypic presentation, even for the same mtDNA mutation.In this chapter, we summarize our current understanding of mtDNA mutations and their role in cardiac involvement. In addition, epigenetic modifications of mtDNA are briefly discussed for future elucidation of their critical role in cardiac involvement. Finally, current strategies for dealing with mitochondrial mutations in cardiac disorders are briefly stated.
Collapse
Affiliation(s)
- Sung Ryul Lee
- Department of Integrated Biomedical Science, Cardiovascular and Metabolic Disease Center, College of Medicine, Inje University, Busan, 47392, South Korea
| | - Jin Han
- National Research Laboratory for Mitochondrial Signaling, Cardiovascular and Metabolic Disease Center, Department of Physiology, College of Medicine, Inje University, Busan, 47392, South Korea.
| |
Collapse
|
142
|
Gomez-Velazquez M, Badia-Careaga C, Lechuga-Vieco AV, Nieto-Arellano R, Tena JJ, Rollan I, Alvarez A, Torroja C, Caceres EF, Roy AR, Galjart N, Delgado-Olguin P, Sanchez-Cabo F, Enriquez JA, Gomez-Skarmeta JL, Manzanares M. CTCF counter-regulates cardiomyocyte development and maturation programs in the embryonic heart. PLoS Genet 2017; 13:e1006985. [PMID: 28846746 PMCID: PMC5591014 DOI: 10.1371/journal.pgen.1006985] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 09/08/2017] [Accepted: 08/17/2017] [Indexed: 11/27/2022] Open
Abstract
Cardiac progenitors are specified early in development and progressively differentiate and mature into fully functional cardiomyocytes. This process is controlled by an extensively studied transcriptional program. However, the regulatory events coordinating the progression of such program from development to maturation are largely unknown. Here, we show that the genome organizer CTCF is essential for cardiogenesis and that it mediates genomic interactions to coordinate cardiomyocyte differentiation and maturation in the developing heart. Inactivation of Ctcf in cardiac progenitor cells and their derivatives in vivo during development caused severe cardiac defects and death at embryonic day 12.5. Genome wide expression analysis in Ctcf mutant hearts revealed that genes controlling mitochondrial function and protein production, required for cardiomyocyte maturation, were upregulated. However, mitochondria from mutant cardiomyocytes do not mature properly. In contrast, multiple development regulatory genes near predicted heart enhancers, including genes in the IrxA cluster, were downregulated in Ctcf mutants, suggesting that CTCF promotes cardiomyocyte differentiation by facilitating enhancer-promoter interactions. Accordingly, loss of CTCF disrupts gene expression and chromatin interactions as shown by chromatin conformation capture followed by deep sequencing. Furthermore, CRISPR-mediated deletion of an intergenic CTCF site within the IrxA cluster alters gene expression in the developing heart. Thus, CTCF mediates local regulatory interactions to coordinate transcriptional programs controlling transitions in morphology and function during heart development. Properly regulated gene expression in time and space during development and differentiation requires not only transcriptional inputs, but also specific structuring of the chromatin. CTCF is a DNA binding factor that is believed to be critical for this process through binding to tens of thousands of sites across the genome. Despite the knowledge gained in recent years on the role of CTCF in genome organization, its functions in vivo are poorly understood. To address this issue, we studied the effect of genetically deleting CTCF in differentiating cardiomyocytes at early stages of mouse development. Surprisingly only a fraction of genes change their expression when CTCF is removed. Importantly, misregulated genes control opposing genetic programs in charge of development and patterning on one hand, and cardiomyocyte maturation on the other. This imbalance leads to faulty mitochondria and incorrect expression of cardiac patterning genes, and subsequent embryonic lethality. Our results suggest that CTCF is not necessary for maintenance of global genome structure, but coordinates dynamic genetic programs controlling phenotypic transitions in developing cells and tissues.
Collapse
Affiliation(s)
| | | | - Ana Victoria Lechuga-Vieco
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | | | - Juan J. Tena
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide-Junta de Andalucía, Seville, Spain
| | - Isabel Rollan
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Alba Alvarez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Carlos Torroja
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Eva F. Caceres
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Anna R. Roy
- Translational Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Niels Galjart
- Department of Cell Biology and Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Paul Delgado-Olguin
- Translational Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Heart and Stroke Richard Lewar Centre of Excellence, Toronto, Ontario, Canada
| | | | | | - Jose Luis Gomez-Skarmeta
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide-Junta de Andalucía, Seville, Spain
| | - Miguel Manzanares
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
- * E-mail:
| |
Collapse
|
143
|
Sullivan KAM, Platt RN, Bradley RD, Ray DA. Whole mitochondrial genomes provide increased resolution and indicate paraphyly in deer mice. BMC ZOOL 2017. [DOI: 10.1186/s40850-017-0020-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
|
144
|
Balasubramaniam M, Reis RJS, Ayyadevara S, Wang X, Ganne A, Khaidakov M. Involvement of tRNAs in replication of human mitochondrial DNA and modifying effects of telomerase. Mech Ageing Dev 2017; 166:55-63. [PMID: 28765009 DOI: 10.1016/j.mad.2017.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/14/2017] [Accepted: 07/17/2017] [Indexed: 01/07/2023]
Abstract
Overexpression of telomerase has been shown to significantly increase the lifespan of mice. When mechanistically attributed to repair of critically short telomeres, the lifespan extending action of telomerase cannot be reconciled with the observation that telomerase-null mice do not exhibit shortening of lifespan for at least two generations. We hypothesized that telomerase may interfere with replication of mitochondrial DNA (mtDNA) in a way that reduces formation of deletions - the primary cause of age-dependent cell attrition in non-renewable cells such as myocytes and neurons. Here we show that several tRNA genes may function as alternative origins of replication (ORIs). We also show that telomerase interacts with canonical light strand ORI (ORIL) and tRNAs and modifies their activities. Our results suggest that replication of mitochondrial DNA (mtDNA) proceeds through a variety of mechanisms resulting in a mixture of classic strand-displacement mode, and coupled replication of heavy and light strands. Our results also suggest that effects of telomerase may arise from binding ORIL and thus limiting contribution of the deletion-prone strand displacement mode to mtDNA synthesis. These findings imply that it may be possible to uncouple detrimental and beneficial effects of telomerase, and thereby to improve telomerase-based strategies to extend lifespan.
Collapse
Affiliation(s)
- Meenakshisundaram Balasubramaniam
- Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States; Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, United States
| | - Robert J Shmookler Reis
- Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States; Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, United States
| | - Srinivas Ayyadevara
- Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States; Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, United States
| | - Xianwei Wang
- Xinxiang Medical University, Xinxiang, Henan, People's Republic of China
| | - Akshatha Ganne
- Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States; University of Arkansas at Little Rock-University of Arkansas for Medical Sciences Bioinformatics Program, United States
| | - Magomed Khaidakov
- Central Arkansas Veterans Healthcare System, Little Rock, AR 72205, United States; Xinxiang Medical University, Xinxiang, Henan, People's Republic of China; Department of Medicine, Division of Gastroenterology and Hepatology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, United States.
| |
Collapse
|
145
|
Silva SR, Alvarenga DO, Aranguren Y, Penha HA, Fernandes CC, Pinheiro DG, Oliveira MT, Michael TP, Miranda VFO, Varani AM. The mitochondrial genome of the terrestrial carnivorous plant Utricularia reniformis (Lentibulariaceae): Structure, comparative analysis and evolutionary landmarks. PLoS One 2017; 12:e0180484. [PMID: 28723946 PMCID: PMC5516982 DOI: 10.1371/journal.pone.0180484] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 05/13/2017] [Indexed: 11/18/2022] Open
Abstract
The carnivorous plants of the family Lentibulariaceae have attained recent attention not only because of their interesting lifestyle, but also because of their dynamic nuclear genome size. Lentibulariaceae genomes span an order of magnitude and include species with the smallest genomes in angiosperms, making them a powerful system to study the mechanisms of genome expansion and contraction. However, little is known about mitochondrial DNA (mtDNA) sequences of this family, and the evolutionary forces that shape this organellar genome. Here we report the sequencing and assembly of the complete mtDNA from the endemic terrestrial Brazilian species Utricularia reniformis. The 857,234bp master circle mitochondrial genome encodes 70 transcriptionaly active genes (42 protein-coding, 25 tRNAs and 3 rRNAs), covering up to 7% of the mtDNA. A ltrA-like protein related to splicing and mobility and a LAGLIDADG homing endonuclease have been identified in intronic regions, suggesting particular mechanisms of genome maintenance. RNA-seq analysis identified properties with putative diverse and important roles in genome regulation and evolution: 1) 672kbp (78%) of the mtDNA is covered by full-length reads; 2) most of the 243kbp intergenic regions exhibit transcripts; and 3) at least 69 novel RNA editing sites in the protein-coding genes. Additional genomic features are hypothetical ORFs (48%), chloroplast insertions, including truncated plastid genes that have been lost from the chloroplast DNA (5%), repeats (5%), relics of transposable elements mostly related to LTR retrotransposons (5%), and truncated mitovirus sequences (0.4%). Phylogenetic analysis based on 32 different Lamiales mitochondrial genomes corroborate that Lentibulariaceae is a monophyletic group. In summary, the U. reniformis mtDNA represents the eighth largest plant mtDNA described to date, shedding light on the genomic trends and evolutionary characteristics and phylogenetic history of the family Lentibulariaceae.
Collapse
Affiliation(s)
- Saura R. Silva
- Departamento de Botânica, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil
| | - Danillo O. Alvarenga
- Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (Unesp), Jaboticabal, São Paulo, Brazil
| | - Yani Aranguren
- Departamento de Biologia Aplicada à Agropecuária, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (Unesp), Jaboticabal, São Paulo, Brazil
| | - Helen A. Penha
- Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (Unesp), Jaboticabal, São Paulo, Brazil
| | - Camila C. Fernandes
- Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (Unesp), Jaboticabal, São Paulo, Brazil
| | - Daniel G. Pinheiro
- Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (Unesp), Jaboticabal, São Paulo, Brazil
| | - Marcos T. Oliveira
- Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (Unesp), Jaboticabal, São Paulo, Brazil
| | - Todd P. Michael
- Computational Genomics, Ibis Bioscience, Carlsbad, CA, United States of America
| | - Vitor F. O. Miranda
- Departamento de Biologia Aplicada à Agropecuária, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (Unesp), Jaboticabal, São Paulo, Brazil
| | - Alessandro M. Varani
- Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (Unesp), Jaboticabal, São Paulo, Brazil
| |
Collapse
|
146
|
Kowluru RA. Diabetic retinopathy, metabolic memory and epigenetic modifications. Vision Res 2017; 139:30-38. [PMID: 28700951 DOI: 10.1016/j.visres.2017.02.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/22/2017] [Accepted: 02/26/2017] [Indexed: 02/07/2023]
Abstract
Retinopathy, a sight-threatening disease, remains one of the most feared complications of diabetes. Although hyperglycemia is the main initiator, progression of diabetic retinopathy continues even after re-institution of normal glycemic control in diabetic patients, and the deleterious effects of prior hyperglycemic insult depend on the duration and the severity of this insult, suggesting a 'metabolic memory' phenomenon. Metabolic memory phenomenon is successfully duplicated in the experimental models of diabetic retinopathy. Hyperglycemia, in addition to initiating many other biochemical and functional abnormalities and altering expression of genes associated with them, also increases oxidative stress. Increased production of cytosolic reactive oxygen species dysfunctions the mitochondria, and a compromised antioxidant defense system becomes overwhelmed to neutralize free radicals. With the duration of diabetes extending, mitochondrial DNA (mtDNA) is also damaged, and transcription of mtDNA-encoded genes, important for function of the electron transport chain, is compromised. This fuels into a 'self-propagating' vicious cycle of free radicals, and retinopathy continues to progress. Hyperglycemic insult also affects the enzymatic machinery responsible for epigenetic modifications; these modifications alter gene expression without affecting the DNA sequence. Histones and/or DNA modifications of many enzymes, important in mitochondrial homeostasis, affect their activities and disturb mitochondrial homeostasis. Experimental models have shown that these epigenetic modifications have potential to halt only if normal glycemia is maintained from the day of induction of diabetes (streptozotocin) in rats, but if hyperglycemia is allowed to proceed even for couple months before initiation of normal glycemia, these epigenetic modification resist reversal. Supplementation of a therapy targeted to prevent increased oxidative stress or epigenetic modifications, during the normal glucose phase, which has followed high glucose insult, however, helps ameliorate these abnormalities and prevents the progression of diabetic retinopathy. Thus, without undermining the importance of tight glycemic control for a diabetic patient, supplementation of their 'best possible' glycemic control with such targeted therapies has potential to retard further progression of this blinding disease.
Collapse
Affiliation(s)
- Renu A Kowluru
- Kresge Eye Institute, Wayne State University, Detroit, MI, United States.
| |
Collapse
|
147
|
Siibak T, Clemente P, Bratic A, Bruhn H, Kauppila TES, Macao B, Schober FA, Lesko N, Wibom R, Naess K, Nennesmo I, Wedell A, Peter B, Freyer C, Falkenberg M, Wredenberg A. A multi-systemic mitochondrial disorder due to a dominant p.Y955H disease variant in DNA polymerase gamma. Hum Mol Genet 2017; 26:2515-2525. [PMID: 28430993 PMCID: PMC5886115 DOI: 10.1093/hmg/ddx146] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 04/11/2017] [Indexed: 12/28/2022] Open
Abstract
Mutations in the mitochondrial DNA polymerase, POLG, are associated with a variety of clinical presentations, ranging from early onset fatal brain disease in Alpers syndrome to chronic progressive external ophthalmoplegia. The majority of mutations are linked with disturbances of mitochondrial DNA (mtDNA) integrity and maintenance. On a molecular level, depending on their location within the enzyme, mutations either lead to mtDNA depletion or the accumulation of multiple mtDNA deletions, and in some cases these molecular changes can be correlated to the clinical presentation. We identified a patient with a dominant p.Y955H mutation in POLG, presenting with a severe, early-onset multi-systemic mitochondrial disease with bilateral sensorineural hearing loss, cataract, myopathy, and liver failure. Using a combination of disease models of Drosophila melanogaster and in vitro biochemistry analysis, we compare the molecular consequences of the p.Y955H mutation to the well-documented p.Y955C mutation. We demonstrate that both mutations affect mtDNA replication and display a dominant negative effect, with the p.Y955H allele resulting in a more severe polymerase dysfunction.
Collapse
Affiliation(s)
- Triinu Siibak
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg SE-405?30, Sweden
| | - Paula Clemente
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, SE-171 77, Sweden.,Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Ana Bratic
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne D-50931, Germany
| | - Helene Bruhn
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden
| | - Timo E S Kauppila
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne D-50931, Germany
| | - Bertil Macao
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg SE-405?30, Sweden
| | - Florian A Schober
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, SE-171 77, Sweden.,Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden
| | - Nicole Lesko
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden
| | - Rolf Wibom
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden
| | - Karin Naess
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden
| | - Inger Nennesmo
- Department of Pathology, Karolinska University Hospital, SE-171?77 Stockholm, Sweden
| | - Anna Wedell
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden.,Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm SE-171 76, Sweden
| | - Bradley Peter
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg SE-405?30, Sweden
| | - Christoph Freyer
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, SE-171 77, Sweden.,Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden
| | - Maria Falkenberg
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, University of Gothenburg, Gothenburg SE-405?30, Sweden
| | - Anna Wredenberg
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, SE-171 77, Sweden.,Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm SE-171 77, Sweden.,Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm SE-171 76, Sweden
| |
Collapse
|
148
|
The role of the mtDNA set point in differentiation, development and tumorigenesis. Biochem J 2017; 473:2955-71. [PMID: 27679856 DOI: 10.1042/bcj20160008] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 06/06/2016] [Indexed: 01/06/2023]
Abstract
Mitochondrial DNA replication is critical for maintaining mtDNA copy number to generate sufficient cellular energy that is required for development and for functional cells. In early development, mtDNA copy number is strictly regulated at different stages, and, as a result, the establishment of the mtDNA set point is required for sequential cell lineage commitment. The failure to establish the mtDNA set point results in incomplete differentiation or embryonic arrest. The regulation of mtDNA copy number during differentiation is closely associated with cellular gene expression, especially with the pluripotency network, and DNA methylation profiles. The findings from cancer research highlight the relationship between mitochondrial function, mtDNA copy number and DNA methylation in regulating differentiation. DNA methylation at exon 2 of DNA polymerase gamma subunit A (POLGA) has been shown to be a key factor, which can be modulated to change the mtDNA copy number and cell fate of differentiating and tumour cells. The present review combines multi-disciplinary data from mitochondria, development, epigenetics and tumorigenesis, which could provide novel insights for further research, especially for developmental disorders and cancers.
Collapse
|
149
|
Roubicek DA, Souza-Pinto NCD. Mitochondria and mitochondrial DNA as relevant targets for environmental contaminants. Toxicology 2017; 391:100-108. [PMID: 28655544 DOI: 10.1016/j.tox.2017.06.012] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 06/20/2017] [Accepted: 06/21/2017] [Indexed: 10/19/2022]
Abstract
The mitochondrial DNA (mtDNA) is a closed circular molecule that encodes, in humans, 13 polypeptides components of the oxidative phosphorylation complexes. Integrity of the mitochondrial genome is essential for mitochondrial function and cellular homeostasis, and mutations and deletions in the mtDNA lead to oxidative stress, mitochondrial dysfunction and cell death. In vitro and in situ studies suggest that when exposed to certain genotoxins, mtDNA accumulates more damage than nuclear DNA, likely owing to its organization and localization in the mitochondrial matrix, which tends to accumulate lipophilic, positively charged molecules. In that regard, several relevant environmental and occupational contaminants have physical-chemical characteristics that indicate that they might accumulate in mitochondria and target mtDNA. Nonetheless, very little is known so far about mtDNA damage and mitochondrial dysfunction due to environmental exposure, either in model organisms or in humans. In this article, we discuss some of the characteristics of mtDNA which render it a potentially relevant target for damage by environmental contaminants, as well as possible functional consequences of damage/mutation accumulation. In addition, we review the data available in the literature focusing on mitochondrial effects of the most common classes of environmental pollutants. From that, we conclude that several lines of experimental evidence support the idea that mitochondria and mtDNA are susceptible and biologically relevant targets for pollutants, and more studies, including mechanistic ones, are needed to shed more light into the contribution of mitochondrial dysfunction to the environmental and human health effects of chemical exposure.
Collapse
Affiliation(s)
- Deborah A Roubicek
- Dept. of Environmental Analyses, São Paulo State Environmental Agency, CETESB, Av. Prof. Frederico Hermann Jr, 345, 05459-900, São Paulo, SP, Brazil
| | - Nadja C de Souza-Pinto
- Depto. de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo SP 05508-000, Brazil.
| |
Collapse
|
150
|
Mitochondrial Nucleoid: Shield and Switch of the Mitochondrial Genome. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:8060949. [PMID: 28680532 PMCID: PMC5478868 DOI: 10.1155/2017/8060949] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 03/06/2017] [Accepted: 04/03/2017] [Indexed: 11/18/2022]
Abstract
Mitochondria preserve very complex and distinctively unique machinery to maintain and express the content of mitochondrial DNA (mtDNA). Similar to chromosomes, mtDNA is packaged into discrete mtDNA-protein complexes referred to as a nucleoid. In addition to its role as a mtDNA shield, over 50 nucleoid-associated proteins play roles in mtDNA maintenance and gene expression through either temporary or permanent association with mtDNA or other nucleoid-associated proteins. The number of mtDNA(s) contained within a single nucleoid is a fundamental question but remains a somewhat controversial issue. Disturbance in nucleoid components and mutations in mtDNA were identified as significant in various diseases, including carcinogenesis. Significant interest in the nucleoid structure and its regulation has been stimulated in relation to mitochondrial diseases, which encompass diseases in multicellular organisms and are associated with accumulation of numerous mutations in mtDNA. In this review, mitochondrial nucleoid structure, nucleoid-associated proteins, and their regulatory roles in mitochondrial metabolism are briefly addressed to provide an overview of the emerging research field involving mitochondrial biology.
Collapse
|