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Lesnik C, Kaletsky R, Ashraf JM, Sohrabi S, Cota V, Sengupta T, Keyes W, Luo S, Murphy CT. Enhanced branched-chain amino acid metabolism improves age-related reproduction in C. elegans. Nat Metab 2024; 6:724-740. [PMID: 38418585 DOI: 10.1038/s42255-024-00996-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 01/25/2024] [Indexed: 03/01/2024]
Abstract
Reproductive ageing is one of the earliest human ageing phenotypes, and mitochondrial dysfunction has been linked to oocyte quality decline; however, it is not known which mitochondrial metabolic processes are critical for oocyte quality maintenance with age. To understand how mitochondrial processes contribute to Caenorhabditis elegans oocyte quality, we characterized the mitochondrial proteomes of young and aged wild-type and long-reproductive daf-2 mutants. Here we show that the mitochondrial proteomic profiles of young wild-type and daf-2 worms are similar and share upregulation of branched-chain amino acid (BCAA) metabolism pathway enzymes. Reduction of the BCAA catabolism enzyme BCAT-1 shortens reproduction, elevates mitochondrial reactive oxygen species levels, and shifts mitochondrial localization. Moreover, bcat-1 knockdown decreases oocyte quality in daf-2 worms and reduces reproductive capability, indicating the role of this pathway in the maintenance of oocyte quality with age. Notably, oocyte quality deterioration can be delayed, and reproduction can be extended in wild-type animals both by bcat-1 overexpression and by supplementing with vitamin B1, a cofactor needed for BCAA metabolism.
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Affiliation(s)
- Chen Lesnik
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- LSI Genomics, Princeton University, Princeton, NJ, USA
- Faculty of Natural Sciences, Department of Human Biology, University of Haifa, Haifa, Israel
| | - Rachel Kaletsky
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- LSI Genomics, Princeton University, Princeton, NJ, USA
| | - Jasmine M Ashraf
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- LSI Genomics, Princeton University, Princeton, NJ, USA
| | - Salman Sohrabi
- LSI Genomics, Princeton University, Princeton, NJ, USA
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA
| | - Vanessa Cota
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- LSI Genomics, Princeton University, Princeton, NJ, USA
- Department of Biology, Tacoma Community College, Tacoma, WA, USA
| | - Titas Sengupta
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- LSI Genomics, Princeton University, Princeton, NJ, USA
| | - William Keyes
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- LSI Genomics, Princeton University, Princeton, NJ, USA
| | - Shijing Luo
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- LSI Genomics, Princeton University, Princeton, NJ, USA
| | - Coleen T Murphy
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
- LSI Genomics, Princeton University, Princeton, NJ, USA.
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2
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Cheng Q, Liu QQ, Lu CA. A state-of-the-science review of using mitochondrial DNA copy number as a biomarker for environmental exposure. Environ Pollut 2024; 346:123642. [PMID: 38402934 DOI: 10.1016/j.envpol.2024.123642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 02/06/2024] [Accepted: 02/22/2024] [Indexed: 02/27/2024]
Abstract
Mitochondria are bioenergetic, biosynthetic, and signaling organelles in eukaryotes, and contain their own genomes, mitochondrial DNA (mtDNA), to supply energy to cells by generating ATP via oxidative phosphorylation. Therefore, the threat to mitochondria' integrity and health resulting from environmental exposure could induce adverse health effects in organisms. In this review, we summarized the association between mtDNA copy number (mtDNAcn), and environmental exposures as reported in the literature. We conducted a literature search in the Web of Science using [Mitochondrial DNA copy number] and [Exposure] as two keywords and employed three selection criteria for the final inclusion of 97 papers for review. The consensus of data was that mtDNAcn could be used as a plausible biomarker for cumulative exposures to environmental chemical and physical agents. In order to furtherly expand the application of mtDNAcn in ecological and environmental health research, we suggested a series of algorithms aiming to standardize the calculation of mtDNAcn based on the PCR results in this review. We also discussed the pitfalls of using whole blood/plasma samples for mtDNAcn measurements and regard buccal cells a plausible and practical alternative. Finally, we recognized the importance of better understanding the mechanistic analysis and regulatory mechanism of mtDNAcn, in particular the signals release and regulation pathways. We believe that the development of using mtDNAcn as an exposure biomarker will revolutionize the evaluation of chronic sub-lethal toxicity of chemicals to organisms in ecological and environmental health research that has not yet been implemented.
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Affiliation(s)
- Qing Cheng
- College of Resources and Environment, Southwest University, Chongqing, 400715, People's Republic of China
| | - Qing Qing Liu
- College of Resources and Environment, Southwest University, Chongqing, 400715, People's Republic of China
| | - Chensheng Alex Lu
- College of Resources and Environment, Southwest University, Chongqing, 400715, People's Republic of China; School of Public Health, University of Washington, Seattle, WA, 98195, USA.
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3
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Rathor L, Curry S, Park Y, McElroy T, Robles B, Sheng Y, Chen WW, Min K, Xiao R, Lee MH, Han SM. Mitochondrial stress in GABAergic neurons non-cell autonomously regulates organismal health and aging. bioRxiv 2024:2024.03.20.585932. [PMID: 38585797 PMCID: PMC10996468 DOI: 10.1101/2024.03.20.585932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Mitochondrial stress within the nervous system can trigger non-cell autonomous responses in peripheral tissues. However, the specific neurons involved and their impact on organismal aging and health have remained incompletely understood. Here, we demonstrate that mitochondrial stress in γ-aminobutyric acid-producing (GABAergic) neurons in Caenorhabditis elegans ( C. elegans ) is sufficient to significantly alter organismal lifespan, stress tolerance, and reproductive capabilities. This mitochondrial stress also leads to significant changes in mitochondrial mass, energy production, and levels of reactive oxygen species (ROS). DAF-16/FoxO activity is enhanced by GABAergic neuronal mitochondrial stress and mediates the induction of these non-cell-autonomous effects. Moreover, our findings indicate that GABA signaling operates within the same pathway as mitochondrial stress in GABAergic neurons, resulting in non-cell-autonomous alterations in organismal stress tolerance and longevity. In summary, these data suggest the crucial role of GABAergic neurons in detecting mitochondrial stress and orchestrating non-cell-autonomous changes throughout the organism.
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4
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Campbell D, Zuryn S. The mechanisms and roles of mitochondrial dynamics in C. elegans. Semin Cell Dev Biol 2024; 156:266-275. [PMID: 37919144 DOI: 10.1016/j.semcdb.2023.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 10/15/2023] [Accepted: 10/26/2023] [Indexed: 11/04/2023]
Abstract
If mitochondria are the powerhouses of the cell, then mitochondrial dynamics are the power grid that regulates how that energy output is directed and maintained in response to unique physiological demands. Fission and fusion dynamics are highly regulated processes that fine-tune the mitochondrial networks of cells to enable appropriate responses to intrinsic and extrinsic stimuli, thereby maintaining cellular and organismal homeostasis. These dynamics shape many aspects of an organism's healthspan including development, longevity, stress resistance, immunity, and response to disease. In this review, we discuss the latest findings regarding the mechanisms and roles of mitochondrial dynamics by focussing on the nematode Caenorhabditis elegans. Whole live-animal studies in C. elegans have enabled a true organismal-level understanding of the impact that mitochondrial dynamics play in homeostasis over a lifetime.
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Affiliation(s)
- Daniel Campbell
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Steven Zuryn
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
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5
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Lesnik C, Kaletsky R, Ashraf JM, Sohrabi S, Cota V, Sengupta T, Keyes W, Luo S, Murphy CT. Enhanced Branched-Chain Amino Acid Metabolism Improves Age-Related Reproduction in C. elegans. bioRxiv 2024:2023.02.09.527915. [PMID: 38370685 PMCID: PMC10871302 DOI: 10.1101/2023.02.09.527915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Reproductive aging is one of the earliest human aging phenotypes, and mitochondrial dysfunction has been linked to oocyte quality decline. However, it is not known which mitochondrial metabolic processes are critical for oocyte quality maintenance with age. To understand how mitochondrial processes contribute to C. elegans oocyte quality, we characterized the mitochondrial proteomes of young and aged wild-type and long-reproductive daf-2 mutants. Here we show that the mitochondrial proteomic profiles of young wild-type and daf-2 worms are similar and share upregulation of branched-chain amino acid (BCAA) metabolism pathway enzymes. Reduction of the BCAA catabolism enzyme BCAT-1 shortens reproduction, elevates mitochondrial reactive oxygen species levels, and shifts mitochondrial localization. Moreover, bcat-1 knockdown decreases oocyte quality in daf-2 worms and reduces reproductive capability, indicating the role of this pathway in the maintenance of oocyte quality with age. Importantly, oocyte quality deterioration can be delayed, and reproduction can be extended in wild-type animals both by bcat-1 overexpression and by supplementing with Vitamin B1, a cofactor needed for BCAA metabolism.
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6
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Li B, Wang H, Jiang C, Zeng X, Zhang T, Liu S, Zhuang Z. Tissue Distribution of mtDNA Copy Number And Expression Pattern of An mtDNA-Related Gene in Three Teleost Fish Species. Integr Org Biol 2023; 5:obad029. [PMID: 37705694 PMCID: PMC10495257 DOI: 10.1093/iob/obad029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 07/05/2023] [Indexed: 09/15/2023] Open
Abstract
Teleosts are the most speciose vertebrates and have diverse swimming performance. Based on swimming duration and speed, teleosts are broadly divided into sustained, prolonged, and burst swimming fish. Teleosts with different swimming performance have different energy requirements. In addition, energy requirement also varies among different tissues. As mitochondrial DNA (mtDNA) copy number is correlated with ATP production, we speculated that mtDNA copy number varies among fish with different swimming performance, as well as among different tissues. In other species, mtDNA copy number is regulated by tfam (mitochondrial transcription factor A) through mtDNA compaction and mito-genome replication initiation. In order to clarify the tissue distribution of mtDNA copy number and expression pattern of tfam in teleosts with disparate swimming performance, we selected representative fish with sustained swimming (Pseudocaranx dentex), prolonged swimming (Takifugu rubripes), and burst swimming (Paralichthys olivaceus). We measured mtDNA copy number and tfam gene expression in 10 tissues of these three fish. The results showed the mtDNA content pattern of various tissues was broadly consistent among three fish, and high-energy demanding tissues contain higher mtDNA copy number. Slow-twitch muscles with higher oxidative metabolism possess a greater content of mtDNA than fast-twitch muscles. In addition, relatively higher mtDNA content in fast-twitch muscle of P. olivaceus compared to the other two fish could be an adaptation to their frequent burst swimming demands. And the higher mtDNA copy number in heart of P. dentex could meet their oxygen transport demands of long-distance swimming. However, tfam expression was not significantly correlated with mtDNA copy number in these teleosts, suggesting tfam may be not the only factor regulating mtDNA content among various tissues. This study can lay a foundation for studying the role of mtDNA in the adaptive evolution of various swimming ability in teleost fish.
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Affiliation(s)
- B Li
- National Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, Shandong, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Marine Life research center, Laoshan Laboratory, Qingdao 266237, Shandong, China
| | - H Wang
- National Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, Shandong, China
| | - C Jiang
- College of Fisheries and Life Science, Dalian Ocean University, Dalian, Liaoning, China
| | - X Zeng
- National Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, Shandong, China
- College of Fisheries and Life Science, Dalian Ocean University, Dalian, Liaoning, China
| | - T Zhang
- Dalian Tianzheng Industry Co., Ltd., Dalian, Liaoning, China
| | - S Liu
- National Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, Shandong, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Marine Life research center, Laoshan Laboratory, Qingdao 266237, Shandong, China
| | - Z Zhuang
- National Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, Shandong, China
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7
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Dai CY, Ng CC, Hung GCC, Kirmes I, Hughes LA, Du Y, Brosnan CA, Ahier A, Hahn A, Haynes CM, Rackham O, Filipovska A, Zuryn S. ATFS-1 counteracts mitochondrial DNA damage by promoting repair over transcription. Nat Cell Biol 2023; 25:1111-1120. [PMID: 37460695 DOI: 10.1038/s41556-023-01192-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 06/19/2023] [Indexed: 08/12/2023]
Abstract
The ability to balance conflicting functional demands is critical for ensuring organismal survival. The transcription and repair of the mitochondrial genome (mtDNA) requires separate enzymatic activities that can sterically compete1, suggesting a life-long trade-off between these two processes. Here in Caenorhabditis elegans, we find that the bZIP transcription factor ATFS-1/Atf5 (refs. 2,3) regulates this balance in favour of mtDNA repair by localizing to mitochondria and interfering with the assembly of the mitochondrial pre-initiation transcription complex between HMG-5/TFAM and RPOM-1/mtRNAP. ATFS-1-mediated transcriptional inhibition decreases age-dependent mtDNA molecular damage through the DNA glycosylase NTH-1/NTH1, as well as the helicase TWNK-1/TWNK, resulting in an enhancement in the functional longevity of cells and protection against decline in animal behaviour caused by targeted and severe mtDNA damage. Together, our findings reveal that ATFS-1 acts as a molecular focal point for the control of balance between genome expression and maintenance in the mitochondria.
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Affiliation(s)
- Chuan-Yang Dai
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Chai Chee Ng
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Grace Ching Ching Hung
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Ina Kirmes
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Laetitia A Hughes
- Harry Perkins Institute of Medical Research, QEII Medical Centre, The University of Western Australia, Nedlands, Western Australia, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, The University of Western Australia, Nedlands, Western Australia, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Yunguang Du
- Department of Molecular, Cell and Cancer Biology, UMass Chan Medical School, Worchester, MA, USA
| | - Christopher A Brosnan
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Arnaud Ahier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Anne Hahn
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Cole M Haynes
- Department of Molecular, Cell and Cancer Biology, UMass Chan Medical School, Worchester, MA, USA
| | - Oliver Rackham
- Harry Perkins Institute of Medical Research, QEII Medical Centre, The University of Western Australia, Nedlands, Western Australia, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, The University of Western Australia, Nedlands, Western Australia, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, Western Australia, Australia
- Curtin Medical School and Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia, Australia
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research, QEII Medical Centre, The University of Western Australia, Nedlands, Western Australia, Australia
- ARC Centre of Excellence in Synthetic Biology, QEII Medical Centre, The University of Western Australia, Nedlands, Western Australia, Australia
- Telethon Kids Institute, Northern Entrance, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Steven Zuryn
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia.
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8
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Grub LK, Held JP, Hansen TJ, Schaffner SH, Canter MR, Malagise EM, Patel MR. A role for N6-methyldeoxyadenosine in C. elegans mitochondrial genome regulation. bioRxiv 2023:2023.03.27.534452. [PMID: 37034795 PMCID: PMC10081187 DOI: 10.1101/2023.03.27.534452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
Epigenetic modifications provide powerful means for transmitting information from parent to progeny. As a maternally inherited genome that encodes essential components of the electron transport chain, the mitochondrial genome (mtDNA) is ideally positioned to serve as a conduit for the transgenerational transmission of metabolic information. Here, we provide evidence that mtDNA of C. elegans contains the epigenetic mark N6-methyldeoxyadenosine (6mA). Bioinformatic analysis of SMRT sequencing data and methylated DNA IP sequencing data reveal that C. elegans mtDNA is methylated at high levels in a site-specific manner. We further confirmed that mtDNA contains 6mA by leveraging highly specific anti-6mA antibodies. Additionally, we find that mtDNA methylation is dynamically regulated in response to antimycin, a mitochondrial stressor. Further, 6mA is increased in nmad-1 mutants and is accompanied by a significant decrease in mtDNA copy number. Our discovery paves the way for future studies to investigate the regulation and inheritance of mitochondrial epigenetics.
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Affiliation(s)
- Lantana K Grub
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
| | - James P Held
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
| | - Tyler J Hansen
- Department of Biochemistry, Vanderbilt University, Nashville, TN
| | | | - Marleigh R Canter
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
| | - Evi M Malagise
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
| | - Maulik R Patel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
- Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN
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9
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Schwartz AZA, Nance J. Germline TFAM levels regulate mitochondrial DNA copy number and mutant heteroplasmy in C. elegans. MicroPubl Biol 2023; 2023:10.17912/micropub.biology.000727. [PMID: 36873298 PMCID: PMC9975812 DOI: 10.17912/micropub.biology.000727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 03/07/2023]
Abstract
The mitochondrial genome (mtDNA) is packaged into discrete protein-DNA complexes called nucleoids. mtDNA packaging factor TFAM (mitochondrial transcription factor-A) promotes nucleoid compaction and is required for mtDNA replication. Here, we investigate how changing TFAM levels affects mtDNA in the Caenorhabditis elegans germ line. We show that increasing germline TFAM activity boosts mtDNA number and significantly increases the relative proportion of a selfish mtDNA mutant, uaDf5 . We conclude that TFAM levels must be tightly controlled to ensure appropriate mtDNA composition in the germ line.
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Affiliation(s)
- Aaron Z A Schwartz
- Department of Cell Biology, NYU Grossman School of Medicine, New York NY 10016.,Skirball Institute of Biomolecular Medicine, NYU Grossman School of Medicine, New York NY 10016
| | - Jeremy Nance
- Department of Cell Biology, NYU Grossman School of Medicine, New York NY 10016.,Skirball Institute of Biomolecular Medicine, NYU Grossman School of Medicine, New York NY 10016
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10
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Hermeling JCW, Herholz M, Baumann L, Cores EC, Zečić A, Hoppe T, Riemer J, Trifunovic A. Mitochondria-originated redox signalling regulates KLF-1 to promote longevity in Caenorhabditis elegans. Redox Biol 2022; 58:102533. [PMID: 36442394 PMCID: PMC9709155 DOI: 10.1016/j.redox.2022.102533] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 11/07/2022] [Indexed: 11/21/2022] Open
Abstract
Alternations of redox metabolism have been associated with the extension of lifespan in roundworm Caenorhabditis elegans, caused by moderate mitochondrial dysfunction, although the underlying signalling cascades are largely unknown. Previously, we identified transcriptional factor Krüppel-like factor-1 (KLF-1) as the main regulator of cytoprotective longevity-assurance pathways in the C. elegans long-lived mitochondrial mutants. Here, we show that KLF-1 translocation to the nucleus and the activation of the signalling cascade is dependent on the mitochondria-derived hydrogen peroxide (H2O2) produced during late developmental phases where aerobic respiration and somatic mitochondrial biogenesis peak. We further show that mitochondrial-inducible superoxide dismutase-3 (SOD-3), together with voltage-dependent anion channel-1 (VDAC-1), is required for the life-promoting H2O2 signalling that is further regulated by peroxiredoxin-3 (PRDX-3). Increased H2O2 release in the cytoplasm activates the p38 MAPK signalling cascade that induces KLF-1 translocation to the nucleus and the activation of transcription of C. elegans longevity-promoting genes, including cytoprotective cytochrome P450 oxidases. Taken together, our results underline the importance of redox-regulated signalling as the key regulator of longevity-inducing pathways in C. elegans, and position precisely timed mitochondria-derived H2O2 in the middle of it.
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Affiliation(s)
- Johannes CW Hermeling
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Germany,Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, Cologne, D-50931, Germany
| | - Marija Herholz
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Germany,Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, Cologne, D-50931, Germany
| | - Linda Baumann
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Germany,Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, Cologne, D-50931, Germany
| | - Estela Cepeda Cores
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Germany,Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, Cologne, D-50931, Germany
| | - Aleksandra Zečić
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Germany,Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, Cologne, D-50931, Germany
| | - Thorsten Hoppe
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Germany,Center for Molecular Medicine Cologne (CMMC), Cologne, D-50931, Germany,Institute for Genetics, University of Cologne, Cologne, D-50674, Germany
| | - Jan Riemer
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Germany,Institute for Biochemistry, University of Cologne, Cologne, D-50931, Germany
| | - Aleksandra Trifunovic
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Germany,Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, Cologne, D-50931, Germany,Center for Molecular Medicine Cologne (CMMC), Cologne, D-50931, Germany,Corresponding author. CECAD Research CenterUniversity of Cologne, Joseph-Stelzmann-Str. 26, Cologne, D-50931, Germany.
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11
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Schwartz AZA, Tsyba N, Abdu Y, Patel MR, Nance J. Independent regulation of mitochondrial DNA quantity and quality in Caenorhabditis elegans primordial germ cells. eLife 2022; 11:e80396. [PMID: 36200990 PMCID: PMC9536838 DOI: 10.7554/elife.80396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 09/15/2022] [Indexed: 11/13/2022] Open
Abstract
Mitochondria harbor an independent genome, called mitochondrial DNA (mtDNA), which contains essential metabolic genes. Although mtDNA mutations occur at high frequency, they are inherited infrequently, indicating that germline mechanisms limit their accumulation. To determine how germline mtDNA is regulated, we examined the control of mtDNA quantity and quality in C. elegans primordial germ cells (PGCs). We show that PGCs combine strategies to generate a low point in mtDNA number by segregating mitochondria into lobe-like protrusions that are cannibalized by adjacent cells, and by concurrently eliminating mitochondria through autophagy, reducing overall mtDNA content twofold. As PGCs exit quiescence and divide, mtDNAs replicate to maintain a set point of ~200 mtDNAs per germline stem cell. Whereas cannibalism and autophagy eliminate mtDNAs stochastically, we show that the kinase PTEN-induced kinase 1 (PINK1), operating independently of Parkin and autophagy, preferentially reduces the fraction of mutant mtDNAs. Thus, PGCs employ parallel mechanisms to control both the quantity and quality of the founding population of germline mtDNAs.
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Affiliation(s)
- Aaron ZA Schwartz
- Department of Cell Biology, NYU Grossman School of MedicineNew YorkUnited States
- Skirball Institute of Biomolecular Medicine, NYU Grossman School of MedicineNew YorkUnited States
| | - Nikita Tsyba
- Department of Biological Sciences, Vanderbilt UniversityNashvilleUnited States
| | - Yusuff Abdu
- Department of Cell Biology, NYU Grossman School of MedicineNew YorkUnited States
- Skirball Institute of Biomolecular Medicine, NYU Grossman School of MedicineNew YorkUnited States
| | - Maulik R Patel
- Department of Biological Sciences, Vanderbilt UniversityNashvilleUnited States
- Department of Cell and Developmental Biology, Vanderbilt University School of MedicineNashvilleUnited States
- Diabetes Research and Training Center, Vanderbilt University School of MedicineNashvilleUnited States
| | - Jeremy Nance
- Department of Cell Biology, NYU Grossman School of MedicineNew YorkUnited States
- Skirball Institute of Biomolecular Medicine, NYU Grossman School of MedicineNew YorkUnited States
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12
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Cota V, Sohrabi S, Kaletsky R, Murphy CT. Oocyte mitophagy is critical for extended reproductive longevity. PLoS Genet 2022; 18:e1010400. [PMID: 36126046 PMCID: PMC9524673 DOI: 10.1371/journal.pgen.1010400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 09/30/2022] [Accepted: 08/29/2022] [Indexed: 11/19/2022] Open
Abstract
Women’s reproductive cessation is the earliest sign of human aging and is caused by decreasing oocyte quality. Similarly, C. elegans’ reproduction declines in mid-adulthood and is caused by oocyte quality decline. Aberrant mitochondrial morphology is a hallmark of age-related dysfunction, but the role of mitochondrial morphology and dynamics in reproductive aging is unclear. We examined the requirements for mitochondrial fusion and fission in oocytes of both wild-type worms and the long-lived, long-reproducing insulin-like receptor mutant daf-2. We find that normal reproduction requires both fusion and fission, but that daf-2 mutants utilize a shift towards fission, but not fusion, to extend their reproductive span and oocyte health. daf-2 mutant oocytes’ mitochondria are punctate (fissioned) and this morphology is primed for mitophagy, as loss of the mitophagy regulator PINK-1 shortens daf-2’s reproductive span. daf-2 mutants maintain oocyte mitochondria quality with age at least in part through a shift toward punctate mitochondrial morphology and subsequent mitophagy. Supporting this model, Urolithin A, a metabolite that promotes mitophagy, extends reproductive span in wild-type mothers–even in mid-reproduction—by maintaining youthful oocytes with age. Our data suggest that promotion of mitophagy may be an effective strategy to maintain oocyte health with age. Female reproductive decline begins in a woman’s 30’s, and has become an increasingly important area of research as more women delay child bearing. Like women, the nematode C. elegans undergoes reproductive senescence starting in mid-life, and its reproductive span is determined by oocyte quality decline with age. One of the hallmarks of aging is an increase in mitochondrial dysfunction that can be driven by aberrant mitochondrial fission and fusion, the main regulators of metabolic function and mitochondrial dynamics. In this study we identified a mechanism that promotes reproductive longevity using mitochondrial fission and mitophagy, the trash compactor of dysfunctional mitochondria. This mechanism led us to test Urolithin A, a common metabolite that promotes mitophagy and extends lifespan in C. elegans, as a possible therapeutic to delay reproductive decline. We suggest promotion of mitophagy in oocytes as a new target to extend reproductive longevity through Urolithin A supplementation.
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Affiliation(s)
- Vanessa Cota
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Salman Sohrabi
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- LSI Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Rachel Kaletsky
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- LSI Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Coleen T. Murphy
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- LSI Genomics, Princeton University, Princeton, New Jersey, United States of America
- * E-mail:
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13
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He XD, Zhang F, Huang Y, Hao JJ, Zhang M, He JB, Pu XM, Li YJ, Zi L, Yu J, Yang XX. Potential indicators of mitochondrial structure and function. Curr Pharm Des 2022; 28:1738-1744. [PMID: 35619320 DOI: 10.2174/1381612828666220520161200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 04/04/2022] [Indexed: 11/22/2022]
Abstract
Mitochondria regulate a range of important physiological and biochemical cellular processes including apoptotic cell death, energy production, calcium homeostasis, oxidative stress, and lipid metabolism. Given their role as the 'engines' of cells, their dysfunction is associated with a variety of disease states. Exploring the relationship between mitochondrial function and disease can reveal the mechanism(s) of drug activity and disease pathology. In this review, we summarized the methods of evaluating the structure and function of mitochondria, including the morphology, membrane fluidity, membrane potential, opening of the membrane permeability transition pore, inner membrane permeabilization, mitochondrial dynamics, mitophagy, oxidative stress, energy metabolism-related enzymes, apoptotic pathway related proteins, calcium concentration, DNA copy number, oxygen consumption, β-oxidation-related genes and proteins, cardiolipin content, and adenosine triphosphate content. We believe that the information presented in this review will help explore the pathological processes of mitochondria in the occurrence and development of diseases, as well as the activity and mechanism of drugs, and the discovery of new drugs.
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Affiliation(s)
- Xu-Dong He
- College of Pharmaceutical Science, Yunnan University of Chinese Medicine, 1076 Yuhua Road, Kunming 650500, China
| | - Fan Zhang
- College of Pharmaceutical Science, Yunnan University of Chinese Medicine, 1076 Yuhua Road, Kunming 650500, China
| | - Ying Huang
- College of Pharmaceutical Science, Yunnan University of Chinese Medicine, 1076 Yuhua Road, Kunming 650500, China
| | - Jun-Jie Hao
- College of Pharmaceutical Science, Yunnan University of Chinese Medicine, 1076 Yuhua Road, Kunming 650500, China
| | - Mei Zhang
- College of Pharmaceutical Science, Yunnan University of Chinese Medicine, 1076 Yuhua Road, Kunming 650500, China
| | - Jin-Biao He
- College of Pharmaceutical Science, Yunnan University of Chinese Medicine, 1076 Yuhua Road, Kunming 650500, China
| | - Xue-Mei Pu
- College of Pharmaceutical Science, Yunnan University of Chinese Medicine, 1076 Yuhua Road, Kunming 650500, China
| | - Yan-Juan Li
- College of Pharmaceutical Science, Yunnan University of Chinese Medicine, 1076 Yuhua Road, Kunming 650500, China
| | - Lei Zi
- College of Pharmaceutical Science, Yunnan University of Chinese Medicine, 1076 Yuhua Road, Kunming 650500, China
| | - Jie Yu
- College of Pharmaceutical Science, Yunnan University of Chinese Medicine, 1076 Yuhua Road, Kunming 650500, China
| | - Xing-Xin Yang
- College of Pharmaceutical Science, Yunnan University of Chinese Medicine, 1076 Yuhua Road, Kunming 650500, China
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14
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Meshnik L, Bar-Yaacov D, Kasztan D, Neiger T, Cohen T, Kishner M, Valenci I, Dadon S, Klein CJ, Vance JM, Nevo Y, Züchner S, Ovadia O, Mishmar D, Ben-Zvi A. Mutant C. elegans mitofusin leads to selective removal of mtDNA heteroplasmic deletions across generations to maintain fitness. BMC Biol 2022; 20:40. [PMID: 35139855 PMCID: PMC8829988 DOI: 10.1186/s12915-022-01241-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 01/28/2022] [Indexed: 11/20/2022] Open
Abstract
Background Mitochondrial DNA (mtDNA) is present at high copy numbers in animal cells, and though characterized by a single haplotype in each individual due to maternal germline inheritance, deleterious mutations and intact mtDNA molecules frequently co-exist (heteroplasmy). A number of factors, such as replicative segregation, mitochondrial bottlenecks, and selection, may modulate the exitance of heteroplasmic mutations. Since such mutations may have pathological consequences, they likely survive and are inherited due to functional complementation via the intracellular mitochondrial network. Here, we hypothesized that compromised mitochondrial fusion would hamper such complementation, thereby affecting heteroplasmy inheritance. Results We assessed heteroplasmy levels in three Caenorhabditis elegans strains carrying different heteroplasmic mtDNA deletions (ΔmtDNA) in the background of mutant mitofusin (fzo-1). Animals displayed severe embryonic lethality and developmental delay. Strikingly, observed phenotypes were relieved during subsequent generations in association with complete loss of ΔmtDNA molecules. Moreover, deletion loss rates were negatively correlated with the size of mtDNA deletions, suggesting that mitochondrial fusion is essential and sensitive to the nature of the heteroplasmic mtDNA mutations. Introducing the ΔmtDNA into a fzo-1;pdr-1;+/ΔmtDNA (PARKIN ortholog) double mutant resulted in a skewed Mendelian progeny distribution, in contrast to the normal distribution in the fzo-1;+/ΔmtDNA mutant, and severely reduced brood size. Notably, the ΔmtDNA was lost across generations in association with improved phenotypes. Conclusions Taken together, our findings show that when mitochondrial fusion is compromised, deleterious heteroplasmic mutations cannot evade natural selection while inherited through generations. Moreover, our findings underline the importance of cross-talk between mitochondrial fusion and mitophagy in modulating the inheritance of mtDNA heteroplasmy. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01241-2.
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Affiliation(s)
- Lana Meshnik
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Dan Bar-Yaacov
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.,Department of Microbiology, Immunology and Genetics, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Dana Kasztan
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Tali Neiger
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Tal Cohen
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Mor Kishner
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Itay Valenci
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Sara Dadon
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Christopher J Klein
- Department of Neurology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Jeffery M Vance
- Dr. John T. Macdonald Foundation Department of Human Genetics and Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Yoram Nevo
- Institute of Neurology, Schneider Children's Medical Center of Israel, Tel-Aviv University, Petach Tikva, Israel
| | - Stephan Züchner
- Dr. John T. Macdonald Foundation Department of Human Genetics and Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Ofer Ovadia
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Dan Mishmar
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Anat Ben-Zvi
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.
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15
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Machiela E, Rudich PD, Traa A, Anglas U, Soo SK, Senchuk MM, Van Raamsdonk JM. Targeting Mitochondrial Network Disorganization is Protective in C. elegans Models of Huntington's Disease. Aging Dis 2021; 12:1753-1772. [PMID: 34631219 PMCID: PMC8460302 DOI: 10.14336/ad.2021.0404] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 04/03/2021] [Indexed: 12/19/2022] Open
Abstract
Huntington’s disease (HD) is an adult-onset neurodegenerative disease caused by a trinucleotide CAG repeat expansion in the HTT gene. While the pathogenesis of HD is incompletely understood, mitochondrial dysfunction is thought to be a key contributor. In this work, we used C. elegans models to elucidate the role of mitochondrial dynamics in HD. We found that expression of a disease-length polyglutamine tract in body wall muscle, either with or without exon 1 of huntingtin, results in mitochondrial fragmentation and mitochondrial network disorganization. While mitochondria in young HD worms form elongated tubular networks as in wild-type worms, mitochondrial fragmentation occurs with age as expanded polyglutamine protein forms aggregates. To correct the deficit in mitochondrial morphology, we reduced levels of DRP-1, the GTPase responsible for mitochondrial fission. Surprisingly, we found that disrupting drp-1 can have detrimental effects, which are dependent on how much expression is decreased. To avoid potential negative side effects of disrupting drp-1, we examined whether decreasing mitochondrial fragmentation by targeting other genes could be beneficial. Through this approach, we identified multiple genetic targets that rescue movement deficits in worm models of HD. Three of these genetic targets, pgp-3, F25B5.6 and alh-12, increased movement in the HD worm model and restored mitochondrial morphology to wild-type morphology. This work demonstrates that disrupting the mitochondrial fission gene drp-1 can be detrimental in animal models of HD, but that decreasing mitochondrial fragmentation by targeting other genes can be protective. Overall, this study identifies novel therapeutic targets for HD aimed at improving mitochondrial health.
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Affiliation(s)
- Emily Machiela
- 1Laboratory of Aging and Neurodegenerative Disease, Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids MI 49503, USA
| | - Paige D Rudich
- 2Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, H4A 3J1, Canada.,3Metabolic Disorders and Complications Program, and Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, H4A 3J1, Canada
| | - Annika Traa
- 2Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, H4A 3J1, Canada.,3Metabolic Disorders and Complications Program, and Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, H4A 3J1, Canada
| | - Ulrich Anglas
- 2Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, H4A 3J1, Canada.,3Metabolic Disorders and Complications Program, and Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, H4A 3J1, Canada
| | - Sonja K Soo
- 2Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, H4A 3J1, Canada.,3Metabolic Disorders and Complications Program, and Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, H4A 3J1, Canada
| | - Megan M Senchuk
- 1Laboratory of Aging and Neurodegenerative Disease, Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids MI 49503, USA
| | - Jeremy M Van Raamsdonk
- 1Laboratory of Aging and Neurodegenerative Disease, Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids MI 49503, USA.,2Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, H4A 3J1, Canada.,3Metabolic Disorders and Complications Program, and Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, H4A 3J1, Canada.,4Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec, Canada.,5Department of Genetics, Harvard Medical School, Boston MA 02115, USA
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16
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Waneka G, Svendsen JM, Havird JC, Sloan DB. Mitochondrial mutations in Caenorhabditis elegans show signatures of oxidative damage and an AT-bias. Genetics 2021; 219:6346985. [PMID: 34849888 DOI: 10.1093/genetics/iyab116] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 07/09/2021] [Indexed: 01/25/2023] Open
Abstract
Rapid mutation rates are typical of mitochondrial genomes (mtDNAs) in animals, but it is not clear why. The difficulty of obtaining measurements of mtDNA mutation that are not biased by natural selection has stymied efforts to distinguish between competing hypotheses about the causes of high mtDNA mutation rates. Several studies which have measured mtDNA mutations in nematodes have yielded small datasets with conflicting conclusions about the relative abundance of different substitution classes (i.e., the mutation spectrum). We therefore leveraged Duplex Sequencing, a high-fidelity DNA sequencing technique, to characterize de novo mtDNA mutations in Caenorhabditis elegans. This approach detected nearly an order of magnitude more mtDNA mutations than documented in any previous nematode mutation study. Despite an existing extreme AT bias in the C. elegans mtDNA (75.6% AT), we found that a significant majority of mutations increase genomic AT content. Compared to some prior studies in nematodes and other animals, the mutation spectrum reported here contains an abundance of CG→AT transversions, supporting the hypothesis that oxidative damage may be a driver of mtDNA mutations in nematodes. Furthermore, we found an excess of G→T and C→T changes on the coding DNA strand relative to the template strand, consistent with increased exposure to oxidative damage. Analysis of the distribution of mutations across the mtDNA revealed significant variation among protein-coding genes and as well as among neighboring nucleotides. This high-resolution view of mitochondrial mutations in C. elegans highlights the value of this system for understanding relationships among oxidative damage, replication error, and mtDNA mutation.
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Affiliation(s)
- Gus Waneka
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA and
| | - Joshua M Svendsen
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA and
| | - Justin C Havird
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA and
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17
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Zhang Q, Wang Z, Zhang W, Wen Q, Li X, Zhou J, Wu X, Guo Y, Liu Y, Wei C, Qian W, Tian Y. The memory of neuronal mitochondrial stress is inherited transgenerationally via elevated mitochondrial DNA levels. Nat Cell Biol 2021; 23:870-80. [PMID: 34341532 DOI: 10.1038/s41556-021-00724-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 06/29/2021] [Indexed: 02/06/2023]
Abstract
The memory of stresses experienced by parents can be passed on to descendants as a forecast of the challenges to come. Here, we discovered that the neuronal mitochondrial perturbation-induced systemic mitochondrial unfolded protein response (UPRmt) in Caenorhabditis elegans can be transmitted to offspring over multiple generations. The transgenerational activation of UPRmt is mediated by maternal inheritance of elevated levels of mitochondrial DNA (mtDNA), which causes the proteostasis stress within mitochondria. Furthermore, results from intercrossing studies using wild C. elegans strains further support that maternal inheritance of higher levels of mtDNA can induce the UPRmt in descendants. The mitokine Wnt signalling pathway is required for the transmission of elevated mtDNA levels across generations, thereby conferring lifespan extension and stress resistance to offspring. Collectively, our results reveal that the nervous system can transmit stress signals across generations by increasing mtDNA in the germline, enabling descendants to better cope with anticipated challenges.
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18
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Abstract
Heteroplasmy refers to the coexistence of more than one variant of the mitochondrial genome (mtDNA). Mutated or partially deleted mtDNAs can induce chronic metabolic impairment and cause mitochondrial diseases when their heteroplasmy levels exceed a critical threshold. These mutant mtDNAs can be maternally inherited or can arise de novo. Compelling evidence has emerged showing that mutant mtDNA levels can vary and change in a nonrandom fashion across generations and amongst tissues of an individual. However, our lack of understanding of the basic cellular and molecular mechanisms of mtDNA heteroplasmy dynamics has made it difficult to predict who will inherit or develop mtDNA-associated diseases. More recently, with the advances in technology and the establishment of tractable model systems, insights into the mechanisms underlying the selection forces that modulate heteroplasmy dynamics are beginning to emerge. In this review, we summarize evidence from different organisms, showing that mutant mtDNA can experience both positive and negative selection. We also review the recently identified mechanisms that modulate heteroplasmy dynamics. Taken together, this is an opportune time to survey the literature and to identify key cellular pathways that can be targeted to develop therapies for diseases caused by heteroplasmic mtDNA mutations.
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Affiliation(s)
- Claudia V Pereira
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Bryan L Gitschlag
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Maulik R Patel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA.,Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, TN, USA
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19
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Jeedigunta SP, Minenkova AV, Palozzi JM, Hurd TR. Avoiding Extinction: Recent Advances in Understanding Mechanisms of Mitochondrial DNA Purifying Selection in the Germline. Annu Rev Genomics Hum Genet 2021; 22:55-80. [PMID: 34038145 DOI: 10.1146/annurev-genom-121420-081805] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mitochondria are unusual organelles in that they contain their own genomes, which are kept apart from the rest of the DNA in the cell. While mitochondrial DNA (mtDNA) is essential for respiration and most multicellular life, maintaining a genome outside the nucleus brings with it a number of challenges. Chief among these is preserving mtDNA genomic integrity from one generation to the next. In this review, we discuss what is known about negative (purifying) selection mechanisms that prevent deleterious mutations from accumulating in mtDNA in the germline. Throughout, we focus on the female germline, as it is the tissue through which mtDNA is inherited in most organisms and, therefore, the tissue that most profoundly shapes the genome. We discuss recent progress in uncovering the mechanisms of germline mtDNA selection, from humans to invertebrates.
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Affiliation(s)
- Swathi P Jeedigunta
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada;
| | - Anastasia V Minenkova
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada;
| | - Jonathan M Palozzi
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada;
| | - Thomas R Hurd
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada;
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20
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Ogurusu T, Sakata K. The Caenorhabditis elegans homolog of human mitochondrial pyrimidine nucleotide transporter regulates glucose transport. Biochem Biophys Res Commun 2021; 557:117-121. [PMID: 33862454 DOI: 10.1016/j.bbrc.2021.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 10/21/2022]
Abstract
Caenorhabditis elegans T09F3.2 is a homolog of the human mitochondrial pyrimidine nucleotide transporter. We isolated a T09F3.2 mutant (TOG2) with a 0.7 kb deletion in T09F3.2, which exhibited low growth and movement. TOG2 worms exhibited high glucose content and low lipid content in intestinal cells and oocytes, suggesting glucose leakage from these cells. The glucose transport inhibitor phloretin improved the growth of TOG2 worms, suggesting that T09F3.2 regulates the phloretin-sensitive glucose transporter FGT-1. The localization of T09F3.2 was examined to assess the regulation of FGT-1 by T09F3.2. Distinct expression of T09F3.2 fused with DsRed-Monomer (T09F3.2:DsRed-Monomer) was observed in the basal domain of intestinal cells and was weakly expressed in many cells. Colocalization of FGT-1 and T09F3.2 was observed in the intestinal cell surface and body wall muscle. This colocalization supports the regulation of FGT-1 by T09F3.2. These results reveal new aspects of glucose transporter regulation.
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Affiliation(s)
- Tarou Ogurusu
- Department of Chemistry and Bioengineering, Iwate University, 4 Ueda, Morioka, Iwate, 020-8551, Japan.
| | - Kazumi Sakata
- Department of Chemistry and Bioengineering, Iwate University, 4 Ueda, Morioka, Iwate, 020-8551, Japan
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21
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King SD, Gray CF, Song L, Mittler R, Padilla PA. The mitochondrial localized CISD-3.1/CISD-3.2 proteins are required to maintain normal germline structure and function in Caenorhabditis elegans. PLoS One 2021; 16:e0245174. [PMID: 33544710 PMCID: PMC7864470 DOI: 10.1371/journal.pone.0245174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/22/2020] [Indexed: 11/18/2022] Open
Abstract
Reproductive organs and developing tissues have high energy demands that require metabolic functions primarily supported by mitochondria function. The highly conserved CISD/NEET iron-sulfur (Fe-S) protein family regulates iron and reactive oxygen homeostasis, both of which are important for mitochondrial function. Disruption of iron and reactive oxygen homeostasis typically leads to detrimental effects. In humans, CISD dysfunction is associated with human health issues including Wolfram syndrome 2. Using C. elegans, we previously determined that the cisd-1, cisd-3.1 and cisd-3.2 have an overlapping role in the regulation of physiological germline apoptosis through the canonical programmed cell death pathway. Here, we isolated the cisd-3.2(pnIs68) mutant that resulted in physiological and fitness defects including germline abnormalities that are associated with abnormal stem cell niche and disrupted formation of bivalent chromosomes. The cisd-3.2(pnIs68) mutation led to complete disruption of the cisd-3.2 gene expression and a decrease in expression of genetically intact cisd-1 and cisd-3.1 genes suggesting an indirect impact of the cisd-3.2(pnIs68) allele. The CISD-3.2 and CISD-3.1 proteins localize to the mitochondria in many tissues throughout development. The cisd-3.2(pnIs68) mutant displays phenotypes associated with mitochondrial dysfunction, including disruption of the mitochondrial network within the germline. These results further support the idea that the CISD protein family is required for mitochondrial function that supports important functions in animals including overall fitness and germline viability.
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Affiliation(s)
- Skylar D. King
- Division of Plant Sciences, College of Agriculture, Food and Natural Resources, Christopher S. Bond Life Sciences Center University of Missouri, Columbia, MO, United States of America
- Department of Surgery, University of Missouri School of Medicine, Christopher S. Bond Life Sciences Center University of Missouri, Columbia, MO, United States of America
| | - Chipo F. Gray
- Department of Biological Sciences, University of North Texas, Denton, TX, United States of America
| | - Luhua Song
- Department of Biological Sciences, University of North Texas, Denton, TX, United States of America
| | - Ron Mittler
- Division of Plant Sciences, College of Agriculture, Food and Natural Resources, Christopher S. Bond Life Sciences Center University of Missouri, Columbia, MO, United States of America
- Department of Surgery, University of Missouri School of Medicine, Christopher S. Bond Life Sciences Center University of Missouri, Columbia, MO, United States of America
| | - Pamela A. Padilla
- Department of Biological Sciences, University of North Texas, Denton, TX, United States of America
- * E-mail:
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22
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Facchinello N, Laquatra C, Locatello L, Beffagna G, Brañas Casas R, Fornetto C, Dinarello A, Martorano L, Vettori A, Risato G, Celeghin R, Meneghetti G, Santoro MM, Delahodde A, Vanzi F, Rasola A, Dalla Valle L, Rasotto MB, Lodi T, Baruffini E, Argenton F, Tiso N. Efficient clofilium tosylate-mediated rescue of POLG-related disease phenotypes in zebrafish. Cell Death Dis 2021; 12:100. [PMID: 33469036 DOI: 10.1038/s41419-020-03359-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 12/08/2020] [Accepted: 12/16/2020] [Indexed: 02/07/2023]
Abstract
The DNA polymerase gamma (Polg) is a nuclear-encoded enzyme involved in DNA replication in animal mitochondria. In humans, mutations in the POLG gene underlie a set of mitochondrial diseases characterized by mitochondrial DNA (mtDNA) depletion or deletion and multiorgan defects, named POLG disorders, for which an effective therapy is still needed. By applying antisense strategies, ENU- and CRISPR/Cas9-based mutagenesis, we have generated embryonic, larval-lethal and adult-viable zebrafish Polg models. Morphological and functional characterizations detected a set of phenotypes remarkably associated to POLG disorders, including cardiac, skeletal muscle, hepatic and gonadal defects, as well as mitochondrial dysfunctions and, notably, a perturbed mitochondria-to-nucleus retrograde signaling (CREB and Hypoxia pathways). Next, taking advantage of preliminary evidence on the candidate molecule Clofilium tosylate (CLO), we tested CLO toxicity and then its efficacy in our zebrafish lines. Interestingly, at well tolerated doses, the CLO drug could successfully rescue mtDNA and Complex I respiratory activity to normal levels, even in mutant phenotypes worsened by treatment with Ethidium Bromide. In addition, the CLO drug could efficiently restore cardio-skeletal parameters and mitochondrial mass back to normal values. Altogether, these evidences point to zebrafish as a valuable vertebrate organism to faithfully phenocopy multiple defects detected in POLG patients. Moreover, this model represents an excellent platform to screen, at the whole-animal level, candidate molecules with therapeutic effects in POLG disorders.
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23
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Abstract
Mitochondrial DNA (mtDNA) copy number is a critical component of overall mitochondrial health. In this chapter, we describe methods for simultaneous isolation of mtDNA and nuclear DNA (nucDNA), and measurement of their respective copy numbers using quantitative PCR. Methods differ depending on the species and cell type of the starting material, and availability of specific PCR reagents. We also briefly describe factors that affect mtDNA copy number and discuss caveats to its use as a biomarker.
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Affiliation(s)
- Tess C Leuthner
- Nicholas School of the Environment, Duke University, Durham, NC, USA
| | - Jessica H Hartman
- Nicholas School of the Environment, Duke University, Durham, NC, USA
| | - Ian T Ryde
- Nicholas School of the Environment, Duke University, Durham, NC, USA
| | - Joel N Meyer
- Nicholas School of the Environment, Duke University, Durham, NC, USA.
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24
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Filograna R, Mennuni M, Alsina D, Larsson NG. Mitochondrial DNA copy number in human disease: the more the better? FEBS Lett 2020; 595:976-1002. [PMID: 33314045 PMCID: PMC8247411 DOI: 10.1002/1873-3468.14021] [Citation(s) in RCA: 180] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/02/2020] [Accepted: 11/26/2020] [Indexed: 12/19/2022]
Abstract
Most of the genetic information has been lost or transferred to the nucleus during the evolution of mitochondria. Nevertheless, mitochondria have retained their own genome that is essential for oxidative phosphorylation (OXPHOS). In mammals, a gene‐dense circular mitochondrial DNA (mtDNA) of about 16.5 kb encodes 13 proteins, which constitute only 1% of the mitochondrial proteome. Mammalian mtDNA is present in thousands of copies per cell and mutations often affect only a fraction of them. Most pathogenic human mtDNA mutations are recessive and only cause OXPHOS defects if present above a certain critical threshold. However, emerging evidence strongly suggests that the proportion of mutated mtDNA copies is not the only determinant of disease but that also the absolute copy number matters. In this review, we critically discuss current knowledge of the role of mtDNA copy number regulation in various types of human diseases, including mitochondrial disorders, neurodegenerative disorders and cancer, and during ageing. We also provide an overview of new exciting therapeutic strategies to directly manipulate mtDNA to restore OXPHOS in mitochondrial diseases.
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Affiliation(s)
- Roberta Filograna
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Mara Mennuni
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - David Alsina
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Nils-Göran Larsson
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
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25
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Kang J, Zhou H, Sun F, Chen Y, Zhao J, Yang WJ, Xu S, Chen C. Caenorhabditis elegans homologue of Fam210 is required for oogenesis and reproduction. J Genet Genomics 2020; 47:694-704. [PMID: 33547005 DOI: 10.1016/j.jgg.2020.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/11/2020] [Accepted: 10/16/2020] [Indexed: 11/30/2022]
Abstract
Mitochondria are the central hub for many metabolic processes, including the citric acid cycle, oxidative phosphorylation, and fatty acid oxidation. Recent studies have identified a new mitochondrial protein family, Fam210, that regulates bone metabolism and red cell development in vertebrates. The model organism Caenorhabditis elegans has a Fam210 gene, y56a3a.22, but it lacks both bones and red blood cells. In this study, we report that Y56A3A.22 plays a crucial role in regulating mitochondrial protein homeostasis and reproduction. The nematode y56a3a.22 is expressed in various tissues, including the intestine, muscle, hypodermis, and germline, and its encoded protein is predominantly localized in mitochondria. y56a3a.22 deletion mutants are sterile owing to impaired oogenesis. Loss of Y56A3A.22 induced mitochondrial unfolded protein response (UPRmt), which is mediated through the ATFS-1-dependent pathway, in tissues such as the intestine, germline, hypodermis, and vulval muscle. We further show that infertility and UPRmt induces by Y56A3A.22 deficiency are not attributed to systemic iron deficiency. Together, our study reveals an important role of Y56A3A.22 in regulating mitochondrial protein homeostasis and oogenesis and provides a new genetic tool for exploring the mechanisms regulating mitochondrial metabolism and reproduction as well as the fundamental role of the Fam210 family.
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Affiliation(s)
- Jing Kang
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hengda Zhou
- Center for Stem Cell and Regenerative Medicine and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Fengxiu Sun
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yongtian Chen
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jianzhi Zhao
- Center for Stem Cell and Regenerative Medicine and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Wei-Jun Yang
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Suhong Xu
- Center for Stem Cell and Regenerative Medicine and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Caiyong Chen
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
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26
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Bora S, Vardhan GSH, Deka N, Khataniar L, Gogoi D, Baruah A. Paraquat exposure over generation affects lifespan and reproduction through mitochondrial disruption in C. elegans. Toxicology 2020; 447:152632. [PMID: 33197508 DOI: 10.1016/j.tox.2020.152632] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 11/06/2020] [Accepted: 11/09/2020] [Indexed: 12/22/2022]
Abstract
Paraquat (methyl viologen), is a non-selective contact herbicide and well known mitochondrial toxicant. Mitochondria are the center of cellular metabolism, and involved in the development, lifespan, and reproduction of an organism. Mitochondria are dynamic organelles that are inherited maternally through the germline and carry multiple copies of their own genome (mtDNA). It is important to understand the effects of acute and chronic stress caused by mitochondrial toxicants over multiple generations at the cellular and organism levels. Using the model nematode C. elegans, we show that acute and chronic exposure to paraquat affects reproduction, longevity, gene expression, and mitochondrial physiology. Acute exposure to paraquat in N2 (wild type) causes induction of mitochondrial unfolded protein response (mtUPR), increased expression of mitochondrial superoxide dismutase, decreased mitochondrial membrane potential (Δψm), a dose-dependent progression from linear to fragmented mitochondria, and dose-dependent changes in longevity. Chronic exposure to a low dose of paraquat (0.035 mM) over multiple generations in N2 causes a progressive decline of fertility, leading to complete loss of fertile embryo production by the third generation. The mutation in CEP-1 [cep-1(gk138)], a key regulator of stress-induced apoptosis in the germline, causes increased sensitivity to chronic paraquat relative to N2 with no fertile embryo production beyond the second generation. Whereas, mitochondrial electron transport chain (complex III) mutant [isp-1(qm150)], which display constitutive activation of mtUPR showed increased tolerance and produced fertile embryo out to the fourth generation. The N2, cep-1(gk138), and isp-1(qm150) strain's lifespan over multiple generations exposed to chronic paraquat were measured. Fertility and lifespan data together indicate a trade-off between reproduction and somatic maintenance during chronic paraquat exposure. We have proposed that mitochondrial signaling, dynamics, and CEP-1 mediated germline apoptosis is involved in this trade-off.
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Affiliation(s)
- Snigdha Bora
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat-13, India
| | | | - Nikhita Deka
- DBT-NECAB, Assam Agricultural University, Jorhat-13, India
| | - Lipika Khataniar
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat-13, India
| | - Debajani Gogoi
- DBT-NECAB, Assam Agricultural University, Jorhat-13, India
| | - Aiswarya Baruah
- Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat-13, India; DBT-NECAB, Assam Agricultural University, Jorhat-13, India.
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27
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Gitschlag BL, Tate AT, Patel MR. Nutrient status shapes selfish mitochondrial genome dynamics across different levels of selection. eLife 2020; 9:56686. [PMID: 32959778 PMCID: PMC7508553 DOI: 10.7554/elife.56686] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 08/17/2020] [Indexed: 12/23/2022] Open
Abstract
Cooperation and cheating are widespread evolutionary strategies. While cheating confers an advantage to individual entities within a group, competition between groups favors cooperation. Selfish or cheater mitochondrial DNA (mtDNA) proliferates within hosts while being selected against at the level of host fitness. How does environment shape cheater dynamics across different selection levels? Focusing on food availability, we address this question using heteroplasmic Caenorhabditis elegans. We find that the proliferation of selfish mtDNA within hosts depends on nutrient status stimulating mtDNA biogenesis in the developing germline. Interestingly, mtDNA biogenesis is not sufficient for this proliferation, which also requires the stress-response transcription factor FoxO/DAF-16. At the level of host fitness, FoxO/DAF-16 also prevents food scarcity from accelerating the selection against selfish mtDNA. This suggests that the ability to cope with nutrient stress can promote host tolerance of cheaters. Our study delineates environmental effects on selfish mtDNA dynamics at different levels of selection.
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Affiliation(s)
- Bryan L Gitschlag
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - Ann T Tate
- Department of Biological Sciences, Vanderbilt University, Nashville, United States
| | - Maulik R Patel
- Department of Biological Sciences, Vanderbilt University, Nashville, United States.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, United States.,Diabetes Research and Training Center, Vanderbilt University School of Medicine, Nashville, United States
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28
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Wei W, Ruvkun G. Lysosomal activity regulates Caenorhabditis elegans mitochondrial dynamics through vitamin B12 metabolism. Proc Natl Acad Sci U S A 2020; 117:19970-81. [PMID: 32737159 DOI: 10.1073/pnas.2008021117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mitochondrial fission and fusion are highly regulated by energy demand and physiological conditions to control the production, activity, and movement of these organelles. Mitochondria are arrayed in a periodic pattern in Caenorhabditis elegans muscle, but this pattern is disrupted by mutations in the mitochondrial fission component dynamin DRP-1. Here we show that the dramatically disorganized mitochondria caused by a mitochondrial fission-defective dynamin mutation is strongly suppressed to a more periodic pattern by a second mutation in lysosomal biogenesis or acidification. Vitamin B12 is normally imported from the bacterial diet via lysosomal degradation of B12-binding proteins and transport of vitamin B12 to the mitochondrion and cytoplasm. We show that the lysosomal dysfunction induced by gene inactivations of lysosomal biogenesis or acidification factors causes vitamin B12 deficiency. Growth of the C. elegans dynamin mutant on an Escherichia coli strain with low vitamin B12 also strongly suppressed the mitochondrial fission defect. Of the two C. elegans enzymes that require B12, gene inactivation of methionine synthase suppressed the mitochondrial fission defect of a dynamin mutation. We show that lysosomal dysfunction induced mitochondrial biogenesis, which is mediated by vitamin B12 deficiency and methionine restriction. S-adenosylmethionine, the methyl donor of many methylation reactions, including histones, is synthesized from methionine by S-adenosylmethionine synthase; inactivation of the sams-1 S-adenosylmethionine synthase also suppresses the drp-1 fission defect, suggesting that vitamin B12 regulates mitochondrial biogenesis and then affects mitochondrial fission via chromatin pathways.
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29
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Gerisch B, Tharyan RG, Mak J, Denzel SI, Popkes-van Oepen T, Henn N, Antebi A. HLH-30/TFEB Is a Master Regulator of Reproductive Quiescence. Dev Cell 2020; 53:316-329.e5. [PMID: 32302543 DOI: 10.1016/j.devcel.2020.03.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 01/28/2020] [Accepted: 03/15/2020] [Indexed: 12/20/2022]
Abstract
All animals have evolved the ability to survive nutrient deprivation, and nutrient signaling pathways are conserved modulators of health and disease. In C. elegans, late-larval starvation provokes the adult reproductive diapause (ARD), a long-lived quiescent state that enables survival for months without food, yet underlying molecular mechanisms remain unknown. Here, we show that ARD is distinct from other forms of diapause, showing little requirement for canonical longevity pathways, autophagy, and fat metabolism. Instead it requires the HLH-30/TFEB transcription factor to promote the morphological and physiological remodeling involved in ARD entry, survival, and recovery, suggesting that HLH-30 is a master regulator of reproductive quiescence. HLH-30 transcriptome and genetic analyses reveal that Max-like HLH factors, AMP-kinase, mTOR, protein synthesis, and mitochondrial fusion are target processes that promote ARD longevity. ARD thus rewires metabolism to ensure long-term survival and may illuminate similar mechanisms acting in stem cell quiescence and long-term fasting.
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Affiliation(s)
- Birgit Gerisch
- Department of Molecular Genetics of Ageing, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Rebecca George Tharyan
- Department of Molecular Genetics of Ageing, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Jennifer Mak
- Department of Molecular Genetics of Ageing, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Sarah I Denzel
- Department of Molecular Genetics of Ageing, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases, University of Cologne, Cologne 50931, Germany
| | - Till Popkes-van Oepen
- Department of Molecular Genetics of Ageing, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases, University of Cologne, Cologne 50931, Germany
| | - Nadine Henn
- Department of Molecular Genetics of Ageing, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany
| | - Adam Antebi
- Department of Molecular Genetics of Ageing, Max Planck Institute for Biology of Ageing, Cologne 50931, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases, University of Cologne, Cologne 50931, Germany.
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30
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Abstract
Polycystic ovary syndrome (PCOS) is a prevalent hormonal disorder of premenopausal women worldwide and is characterized by reproductive, endocrine, and metabolic abnormalities. The clinical manifestations of PCOS include oligomenorrhea or amenorrhea, hyperandrogenism, ovarian polycystic changes, and infertility. Women with PCOS are at an increased risk of suffering from type 2 diabetes; me\tabolic syndrome; cardiovascular events, such as hypertension, dyslipidemia; gynecological diseases, including infertility, endometrial dysplasia, endometrial cancer, and ovarian malignant tumors; pregnancy complications, such as premature birth, low birthweight, and eclampsia; and emotional and mental disorders in the future. Although numerous studies have focused on PCOS, the underlying pathophysiological mechanisms of this disease remain unclear. Mitochondria play a key role in energy production, and mitochondrial dysfunction at the cellular level can affect systemic metabolic balance. The recent wide acceptance of functional mitochondrial disorders as a correlated factor of numerous diseases has led to the presupposition that abnormal mitochondrial metabolic markers are associated with PCOS. Studies conducted in the past few years have confirmed that increased oxidative stress is associated with the progression and related complications of PCOS and have proven the relationship between other mitochondrial dysfunctions and PCOS. Thus, this review aims to summarize and discuss previous and recent findings concerning the relationship between mitochondrial dysfunction and PCOS.
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Affiliation(s)
- Jingshun Zhang
- grid.452829.0Reproductive Medical Center, Department of Obstetrics and Gynecology, The Second Hospital of Jilin University, Changchun, Jilin China
| | - Yigang Bao
- grid.452829.0Reproductive Medical Center, Department of Obstetrics and Gynecology, The Second Hospital of Jilin University, Changchun, Jilin China
| | - Xu Zhou
- 0000 0004 1760 5735grid.64924.3dCollege of Animal Sciences, Jilin University, Changchun, Jilin China
| | - Lianwen Zheng
- grid.452829.0Reproductive Medical Center, Department of Obstetrics and Gynecology, The Second Hospital of Jilin University, Changchun, Jilin China
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31
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Herholz M, Cepeda E, Baumann L, Kukat A, Hermeling J, Maciej S, Szczepanowska K, Pavlenko V, Frommolt P, Trifunovic A. KLF-1 orchestrates a xenobiotic detoxification program essential for longevity of mitochondrial mutants. Nat Commun 2019; 10:3323. [PMID: 31346165 PMCID: PMC6658563 DOI: 10.1038/s41467-019-11275-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 06/28/2019] [Indexed: 12/29/2022] Open
Abstract
Most manipulations that extend lifespan also increase resistance to various stress factors and environmental cues in a range of animals from yeast to mammals. However, the underlying molecular mechanisms regulating stress resistance during aging are still largely unknown. Here we identify Krüppel-like factor 1 (KLF-1) as a mediator of a cytoprotective response that dictates longevity induced by reduced mitochondrial function. A redox-regulated KLF-1 activation and transfer to the nucleus coincides with the peak of somatic mitochondrial biogenesis that occurs around a transition from larval stage L3 to D1. We further show that KLF-1 activates genes involved in the xenobiotic detoxification programme and identified cytochrome P450 oxidases, the KLF-1 main effectors, as longevity-assurance factors of mitochondrial mutants. Collectively, these findings underline the importance of the xenobiotic detoxification in the mitohormetic, longevity assurance pathway and identify KLF-1 as a central factor in orchestrating this response.
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Affiliation(s)
- Marija Herholz
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931, Cologne, Germany
| | - Estela Cepeda
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931, Cologne, Germany
| | - Linda Baumann
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931, Cologne, Germany
| | - Alexandra Kukat
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931, Cologne, Germany
| | - Johannes Hermeling
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931, Cologne, Germany
| | - Sarah Maciej
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931, Cologne, Germany
| | - Karolina Szczepanowska
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931, Cologne, Germany
| | - Victor Pavlenko
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931, Cologne, Germany
| | - Peter Frommolt
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931, Cologne, Germany
| | - Aleksandra Trifunovic
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931, Cologne, Germany. .,Center for Molecular Medicine Cologne (CMMC), D-50931, Cologne, Germany.
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32
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Charmpilas N, Tavernarakis N. Mitochondrial maturation drives germline stem cell differentiation in Caenorhabditis elegans. Cell Death Differ 2019; 27:601-617. [PMID: 31217501 PMCID: PMC7206027 DOI: 10.1038/s41418-019-0375-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 05/27/2019] [Accepted: 06/03/2019] [Indexed: 01/07/2023] Open
Abstract
The C. elegans germline recapitulates mammalian stem cell niches and provides an effective platform for investigating key aspects of stem cell biology. However, the molecular and physiological requirements for germline stem cell homeostasis remain largely elusive. Here, we report that mitochondrial biogenesis and function are crucial for germline stem cell identity. We show that general transcription activity in germline mitochondria is highly compartmentalized, and determines mitochondrial maturation. RPOM-1, the mitochondrial RNA polymerase, is differentially expressed as germ nuclei progress from the distal to the proximal gonad arm to form oocytes. Mitochondria undergo changes from globular to tubular morphology and become polarized, as they approach the proximal gonad arm. Notably, this mitochondrial maturation trajectory is evolutionarily conserved. We find that a similar transition and temporal mitochondrial RNA polymerase expression profile characterizes differentiation of mammalian stem cells. In C. elegans, ATP, and ROS production increases sharply during maturation. Impaired mitochondrial bioenergetics causes gonad syncytium tumor formation by disrupting the balance between mitosis and differentiation to oocytes, which results in a marked reduction of fecundity. Consequently, compensatory apoptosis is induced in the germline. Sperm-derived signals promote mitochondrial maturation and proper germ cell differentiation via the MEK/ERK kinase pathway. Germ cell fate decisions are determined by a crosstalk between Insulin/IGF-1 and TGF-β signaling, mitochondria and protein synthesis. Our findings demonstrate that mitochondrial transcription activity determines a shift in mitochondrial bioenergetics, which in turn regulates germline stem cell survival and differentiation. Perturbation of mitochondrial transcription hinders proper germ cell differentiation and causes germline tumor development.
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Affiliation(s)
- Nikolaos Charmpilas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece.,Department of Biology, University of Crete, Heraklion, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece. .,Department of Basic Sciences, School of Medicine, University of Crete, 70013, Heraklion, Crete, Greece.
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33
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Revtovich AV, Lee R, Kirienko NV. Interplay between mitochondria and diet mediates pathogen and stress resistance in Caenorhabditis elegans. PLoS Genet 2019; 15:e1008011. [PMID: 30865620 PMCID: PMC6415812 DOI: 10.1371/journal.pgen.1008011] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 02/09/2019] [Indexed: 12/22/2022] Open
Abstract
Diet is a crucial determinant of organismal biology; interactions between the host, its diet, and its microbiota are critical to determining the health of an organism. A variety of genetic and biochemical means were used to assay stress sensitivity in C. elegans reared on two standard laboratory diets: E. coli OP50, the most commonly used food for C. elegans, or E. coli HT115, which is typically used for RNAi-mediated gene knockdown. We demonstrated that the relatively subtle shift to a diet of E. coli HT115 had a dramatic impact on C. elegans's survival after exposure to pathogenic or abiotic stresses. Interestingly, this was independent of canonical host defense pathways. Instead the change arises from improvements in mitochondrial health, likely due to alleviation of a vitamin B12 deficiency exhibited by worms reared on an E. coli OP50 diet. Increasing B12 availability, by feeding on E. coli HT115, supplementing E. coli OP50 with exogenous vitamin B12, or overexpression of the B12 transporter, improved mitochondrial homeostasis and increased resistance. Loss of the methylmalonyl-CoA mutase gene mmcm-1/MUT, which requires vitamin B12 as a cofactor, abolished these improvements, establishing a genetic basis for the E. coli OP50-incurred sensitivity. Our study forges a mechanistic link between a dietary deficiency (nutrition/microbiota) and a physiological consequence (host sensitivity), using the host-microbiota-diet framework.
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Affiliation(s)
- Alexey V. Revtovich
- Department of BioSciences, Rice University, Houston TX, United States of America
| | - Ryan Lee
- Department of BioSciences, Rice University, Houston TX, United States of America
| | - Natalia V. Kirienko
- Department of BioSciences, Rice University, Houston TX, United States of America
- * E-mail:
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34
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Saneto RP. An update on Alpers-Huttenlocher syndrome: pathophysiology of disease and rational treatment designs. Expert Opin Orphan Drugs 2018. [DOI: 10.1080/21678707.2018.1540979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Russell P. Saneto
- Department of Neurology, Division of Pediatric Neurology, University of Washington and Seattle Children’s Hospital, Seattle, WA, USA
- Neuroscience Institute, Center for Integrative Brain Research, Seattle Children’s Hospital, Seattle, WA, USA
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35
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Lakshmanan LN, Yee Z, Ng LF, Gunawan R, Halliwell B, Gruber J. Clonal expansion of mitochondrial DNA deletions is a private mechanism of aging in long-lived animals. Aging Cell 2018; 17:e12814. [PMID: 30043489 PMCID: PMC6156498 DOI: 10.1111/acel.12814] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/25/2018] [Accepted: 06/13/2018] [Indexed: 02/06/2023] Open
Abstract
Disruption of mitochondrial metabolism and loss of mitochondrial DNA (mtDNA) integrity are widely considered as evolutionarily conserved (public) mechanisms of aging (López-Otín et al., Cell, 153, 2013 and 1194). Human aging is associated with loss in skeletal muscle mass and function (Sarcopenia), contributing significantly to morbidity and mortality. Muscle aging is associated with loss of mtDNA integrity. In humans, clonally expanded mtDNA deletions colocalize with sites of fiber breakage and atrophy in skeletal muscle. mtDNA deletions may therefore play an important, possibly causal role in sarcopenia. The nematode Caenorhabditis elegans also exhibits age-dependent decline in mitochondrial function and a form of sarcopenia. However, it is unclear if mtDNA deletions play a role in C. elegans aging. Here, we report identification of 266 novel mtDNA deletions in aging nematodes. Analysis of the mtDNA mutation spectrum and quantification of mutation burden indicates that (a) mtDNA deletions in nematode are extremely rare, (b) there is no significant age-dependent increase in mtDNA deletions, and (c) there is little evidence for clonal expansion driving mtDNA deletion dynamics. Thus, mtDNA deletions are unlikely to drive the age-dependent functional decline commonly observed in C. elegans. Computational modeling of mtDNA dynamics in C. elegans indicates that the lifespan of short-lived animals such as C. elegans is likely too short to allow for significant clonal expansion of mtDNA deletions. Together, these findings suggest that clonal expansion of mtDNA deletions is likely a private mechanism of aging predominantly relevant in long-lived animals such as humans and rhesus monkey and possibly in rodents.
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Affiliation(s)
- Lakshmi Narayanan Lakshmanan
- Institute for Chemical and BioengineeringETH ZurichZurichSwitzerland
- Swiss Institute of Bioinformatics, Quartier Sorge – Batiment GenopodeLausanneSwitzerland
| | - Zhuangli Yee
- Department of BiochemistryYong Loo Lin School of Medicine, National University of SingaporeSingapore
| | - Li Fang Ng
- Ageing Research Laboratory, Science DivisionYale‐NUS CollegeSingaporeSingapore
| | - Rudiyanto Gunawan
- Institute for Chemical and BioengineeringETH ZurichZurichSwitzerland
- Swiss Institute of Bioinformatics, Quartier Sorge – Batiment GenopodeLausanneSwitzerland
| | - Barry Halliwell
- Department of BiochemistryYong Loo Lin School of Medicine, National University of SingaporeSingapore
| | - Jan Gruber
- Department of BiochemistryYong Loo Lin School of Medicine, National University of SingaporeSingapore
- Ageing Research Laboratory, Science DivisionYale‐NUS CollegeSingaporeSingapore
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36
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Burnaevskiy N, Chen S, Mailig M, Reynolds A, Karanth S, Mendenhall A, Van Gilst M, Kaeberlein M. Reactivation of RNA metabolism underlies somatic restoration after adult reproductive diapause in C. elegans. eLife 2018; 7:36194. [PMID: 30070633 PMCID: PMC6089596 DOI: 10.7554/elife.36194] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 08/01/2018] [Indexed: 12/16/2022] Open
Abstract
The mechanisms underlying biological aging are becoming recognized as therapeutic targets to delay the onset of multiple age-related morbidities. Even greater health benefits can potentially be achieved by halting or reversing age-associated changes. C. elegans restore their tissues and normal longevity upon exit from prolonged adult reproductive diapause, but the mechanisms underlying this phenomenon remain unknown. Here, we focused on the mechanisms controlling recovery from adult diapause. Here, we show that functional improvement of post-mitotic somatic tissues does not require germline signaling, germline stem cells, or replication of nuclear or mitochondrial DNA. Instead a large expansion of the somatic RNA pool is necessary for restoration of youthful function and longevity. Treating animals with the drug 5-fluoro-2'-deoxyuridine prevents this restoration by blocking reactivation of RNA metabolism. These observations define a critical early step during exit from adult reproductive diapause that is required for somatic rejuvenation of an adult metazoan animal.
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Affiliation(s)
| | - Shengying Chen
- Department of Pathology, University of Washington, Seattle, United States
| | - Miguel Mailig
- Department of Pathology, University of Washington, Seattle, United States
| | - Anthony Reynolds
- Department of Pathology, University of Washington, Seattle, United States
| | - Shruti Karanth
- Department of Pathology, University of Washington, Seattle, United States
| | | | - Marc Van Gilst
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, United States
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, United States
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37
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Nguyen TT, Caito SW, Zackert WE, West JD, Zhu S, Aschner M, Fessel JP, Roberts LJ. Scavengers of reactive γ-ketoaldehydes extend Caenorhabditis elegans lifespan and healthspan through protein-level interactions with SIR-2.1 and ETS-7. Aging (Albany NY) 2017; 8:1759-80. [PMID: 27514077 PMCID: PMC5032694 DOI: 10.18632/aging.101011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 07/20/2016] [Indexed: 11/25/2022]
Abstract
Isoketals (IsoKs) are highly reactive γ-ketoaldehyde products of lipid peroxidation that covalently adduct lysine side chains in proteins, impairing their function. Using C. elegans as a model organism, we sought to test the hypothesis that IsoKs contribute to molecular aging through adduction and inactivation of specific protein targets, and that this process can be abrogated using salicylamine (SA), a selective IsoK scavenger. Treatment with SA extends adult nematode longevity by nearly 56% and prevents multiple deleterious age-related biochemical and functional changes. Testing of a variety of molecular targets for SA's action revealed the sirtuin SIR-2.1 as the leading candidate. When SA was administered to a SIR-2.1 knockout strain, the effects on lifespan and healthspan extension were abolished. The SIR-2.1-dependent effects of SA were not mediated by large changes in gene expression programs or by significant changes in mitochondrial function. However, expression array analysis did show SA-dependent regulation of the transcription factor ets-7 and associated genes. In ets-7 knockout worms, SA's longevity effects were abolished, similar to sir-2.1 knockouts. However, SA dose-dependently increases ets-7 mRNA levels in non-functional SIR-2.1 mutant, suggesting that both are necessary for SA's complete lifespan and healthspan extension.
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Affiliation(s)
- Thuy T Nguyen
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - Samuel W Caito
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.,Department of Environmental Medicine, University of Rochester, Rochester, NY 14642, USA
| | - William E Zackert
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University, Nashville, TN 37232, USA
| | - James D West
- Division of Allergy, Pulmonary and Critical Care Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Shijun Zhu
- Division of Allergy, Pulmonary and Critical Care Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Michael Aschner
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.,Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Joshua P Fessel
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.,Division of Allergy, Pulmonary and Critical Care Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - L Jackson Roberts
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.,Division of Allergy, Pulmonary and Critical Care Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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38
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Smith RL, Tan JME, Jonker MJ, Jongejan A, Buissink T, Veldhuijzen S, van Kampen AHC, Brul S, van der Spek H. Beyond the polymerase-γ theory: Production of ROS as a mode of NRTI-induced mitochondrial toxicity. PLoS One 2017; 12:e0187424. [PMID: 29095935 PMCID: PMC5667870 DOI: 10.1371/journal.pone.0187424] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/19/2017] [Indexed: 12/17/2022] Open
Abstract
Use of some HIV-1 nucleoside reverse transcriptase inhibitors (NRTI) is associated with severe adverse events. However, the exact mechanisms behind their toxicity has not been fully understood. Mitochondrial dysfunction after chronic exposure to specific NRTIs has predominantly been assigned to mitochondrial polymerase-γ inhibition by NRTIs. However, an increasing amount of data suggests that this is not the sole mechanism. Many NRTI induced adverse events have been linked to the incurrence of oxidative stress, although the causality of events leading to reactive oxygen species (ROS) production and their role in toxicity is unclear. In this study we show that short-term effects of first generation NRTIs, which are rarely discussed in the literature, include inhibition of oxygen consumption, decreased ATP levels and increased ROS production. Collectively these events affect fitness and longevity of C. elegans through mitohormetic signalling events. Furthermore, we demonstrate that these effects can be normalized by addition of the anti-oxidant N-acetylcysteine (NAC), which suggests that ROS likely influence the onset and severity of adverse events upon drug exposure.
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Affiliation(s)
- Reuben L. Smith
- Molecular Biology & Microbial Food Safety, Swammerdam Institute for Life Sciences (SILS), Faculty of Science (FNWI), University of Amsterdam, Amsterdam, The Netherlands
| | - Josephine M. E. Tan
- Molecular Biology & Microbial Food Safety, Swammerdam Institute for Life Sciences (SILS), Faculty of Science (FNWI), University of Amsterdam, Amsterdam, The Netherlands
| | - Martijs J. Jonker
- RNA Biology & Applied Bioinformatics, Swammerdam Institute for Life Sciences (SILS), Faculty of Science (FNWI), University of Amsterdam, Amsterdam, The Netherlands
| | - Aldo Jongejan
- Bioinformatics Laboratory, Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center (AMC), Amsterdam, The Netherlands
| | - Thomas Buissink
- Molecular Biology & Microbial Food Safety, Swammerdam Institute for Life Sciences (SILS), Faculty of Science (FNWI), University of Amsterdam, Amsterdam, The Netherlands
| | - Steve Veldhuijzen
- Molecular Biology & Microbial Food Safety, Swammerdam Institute for Life Sciences (SILS), Faculty of Science (FNWI), University of Amsterdam, Amsterdam, The Netherlands
| | - Antoine H. C. van Kampen
- Bioinformatics Laboratory, Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center (AMC), Amsterdam, The Netherlands
- Biosystems data analysis, Swammerdam Institute for Life Sciences (SILS), Faculty of Science (FNWI), University of Amsterdam, Amsterdam, The Netherlands
| | - Stanley Brul
- Molecular Biology & Microbial Food Safety, Swammerdam Institute for Life Sciences (SILS), Faculty of Science (FNWI), University of Amsterdam, Amsterdam, The Netherlands
| | - Hans van der Spek
- Molecular Biology & Microbial Food Safety, Swammerdam Institute for Life Sciences (SILS), Faculty of Science (FNWI), University of Amsterdam, Amsterdam, The Netherlands
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Abstract
Mitochondria are best known for harboring pathways involved in ATP synthesis through the tricarboxylic acid cycle and oxidative phosphorylation. Major advances in understanding these roles were made with Caenorhabditiselegans mutants affecting key components of the metabolic pathways. These mutants have not only helped elucidate some of the intricacies of metabolism pathways, but they have also served as jumping off points for pharmacology, toxicology, and aging studies. The field of mitochondria research has also undergone a renaissance, with the increased appreciation of the role of mitochondria in cell processes other than energy production. Here, we focus on discoveries that were made using C. elegans, with a few excursions into areas that were studied more thoroughly in other organisms, like mitochondrial protein import in yeast. Advances in mitochondrial biogenesis and membrane dynamics were made through the discoveries of novel functions in mitochondrial fission and fusion proteins. Some of these functions were only apparent through the use of diverse model systems, such as C. elegans Studies of stress responses, exemplified by mitophagy and the mitochondrial unfolded protein response, have also benefitted greatly from the use of model organisms. Recent developments include the discoveries in C. elegans of cell autonomous and nonautonomous pathways controlling the mitochondrial unfolded protein response, as well as mechanisms for degradation of paternal mitochondria after fertilization. The evolutionary conservation of many, if not all, of these pathways ensures that results obtained with C. elegans are equally applicable to studies of human mitochondria in health and disease.
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Affiliation(s)
- Alexander M van der Bliek
- Department of Biological Chemistry, Jonsson Comprehensive Cancer Center and Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, California 90024
| | - Margaret M Sedensky
- Department of Anesthesiology and Pain Medicine, University of Washington and Center for Developmental Therapeutics, Seattle Children's Research Institute, Washington 98101
| | - Phil G Morgan
- Department of Anesthesiology and Pain Medicine, University of Washington and Center for Developmental Therapeutics, Seattle Children's Research Institute, Washington 98101
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40
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Abstract
There are approximately 1500 proteins that are needed for mitochondrial structure and function, most of which are encoded in the nuclear genome (Calvo et al., 2006). Each mitochondrion has its own genome (mtDNA), which in humans encodes 13 polypeptides, 22 tRNAs and 2 rRNAs required for oxidative phosphorylation. The mitochondrial genome of humans and most vertebrates is approximately 16.5kbp, double-stranded, circular, with few non-coding bases. Thus, maintaining mtDNA stability, that is, the ability of the cell to maintain adequate levels of mtDNA template for oxidative phosphorylation is essential and can be impacted by the level of mtDNA mutation currently within the cell or mitochondrion, but also from errors made during normal mtDNA replication, defects in mitochondrial quality control mechanisms, and exacerbated by exposures to exogenous and/or endogenous genotoxic agents. In this review, we expand on the origins and consequences of mtDNA instability, the current state of research regarding the mechanisms by which mtDNA instability can be overcome by cellular and chemical interventions, and the future of research and treatments for mtDNA instability.
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Affiliation(s)
- Sherine S L Chan
- Drug Discovery and Biomedical Sciences, College of Pharmacy, Medical University of South Carolina, Charleston, SC 29425, United States; Neuroene Therapeutics, Mt. Pleasant, SC 29464, United States.
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41
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Lin CCJ, Wang MC. Microbial metabolites regulate host lipid metabolism through NR5A-Hedgehog signalling. Nat Cell Biol 2017; 19:550-557. [PMID: 28436966 PMCID: PMC5635834 DOI: 10.1038/ncb3515] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 03/16/2017] [Indexed: 12/13/2022]
Abstract
Microorganisms and their hosts share the same environment, and microbial metabolic molecules (metabolites) exert crucial effects on host physiology. Environmental factors not only shape the composition of the host's resident microorganisms, but also modulate their metabolism. However, the exact molecular relationship among the environment, microbial metabolites and host metabolism remains largely unknown. Here, we discovered that environmental methionine tunes bacterial methyl metabolism to regulate host mitochondrial dynamics and lipid metabolism in Caenorhabditis elegans through an endocrine crosstalk involving NR5A nuclear receptor and Hedgehog signalling. We discovered that methionine deficiency in bacterial medium decreases the production of bacterial metabolites that are essential for phosphatidylcholine synthesis in C. elegans. Reductions of diundecanoyl and dilauroyl phosphatidylcholines attenuate NHR-25, a NR5A nuclear receptor, and release its transcriptional suppression of GRL-21, a Hedgehog-like protein. The induction of GRL-21 consequently inhibits the PTR-24 Patched receptor cell non-autonomously, resulting in mitochondrial fragmentation and lipid accumulation. Together, our work reveals an environment-microorganism-host metabolic axis regulating host mitochondrial dynamics and lipid metabolism, and discovers NR5A-Hedgehog intercellular signalling that controls these metabolic responses with critical consequences for host health and survival.
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Affiliation(s)
- Chih-Chun Janet Lin
- Huffington Center on Aging, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
| | - Meng C Wang
- Huffington Center on Aging, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.,Dan L. Duncan Cancer Center, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
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42
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Phillips WS, Brown AMV, Howe DK, Peetz AB, Blok VC, Denver DR, Zasada IA. The mitochondrial genome of Globodera ellingtonae is composed of two circles with segregated gene content and differential copy numbers. BMC Genomics 2016; 17:706. [PMID: 27595608 PMCID: PMC5011991 DOI: 10.1186/s12864-016-3047-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 08/27/2016] [Indexed: 01/21/2023] Open
Abstract
Background The evolution of animal mitochondrial (mt) genomes has resulted in a highly conserved structure: a single compact circular chromosome approximately 14 to 20 kb long. Within the last two decades exceptions to this conserved structure, such as the division of the genome into multiple chromosomes, have been reported in a diverse set of metazoans. We report on the two circle multipartite mt genome of a newly described cyst nematode, Globodera ellingtonae. Results The G. ellingtonae mt genome was found to be comprised of two circles, each larger than any other multipartite circular mt chromosome yet reported, and both were larger than the single mt circle of the model nematode Caenorhabditis elegans. The genetic content of the genome was disproportionately divided between the two circles, although they shared a ~6.5 kb non-coding region. The 17.8 kb circle (mtDNA-I) contained ten protein-coding genes and two tRNA genes, whereas the 14.4 kb circle (mtDNA-II) contained two protein-coding genes, 20 tRNA genes and both rRNA genes. Perhaps correlated with this division of genetic content, the copy number of mtDNA-II was more than four-fold that of mtDNA-I in individual nematodes. The difference in copy number increased between second-stage and fourth-stage juveniles. Conclusions The segregation of gene types to different mt circles in G. ellingtonae could provide benefit by localizing gene functional types to independent transcriptional units. This is the first report of both two-circle and several-circle mt genomes within a single genus. The differential copy number associated with this multipartite mt organization could provide a model system for deconstructing mechanisms regulating mtDNA copy number both in somatic cells and during germline development. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3047-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wendy S Phillips
- Horticultural Crops Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Corvallis, OR, USA.
| | - Amanda M V Brown
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - Dana K Howe
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - Amy B Peetz
- Horticultural Crops Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Corvallis, OR, USA
| | - Vivian C Blok
- Cell and Molecular Sciences Group, Dundee Effector Consortium, James Hutton Institute, Dundee, UK
| | - Dee R Denver
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - Inga A Zasada
- Horticultural Crops Research Laboratory, Agricultural Research Service, United States Department of Agriculture, Corvallis, OR, USA
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43
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Luz AL, Meyer JN. Effects of reduced mitochondrial DNA content on secondary mitochondrial toxicant exposure in Caenorhabditis elegans. Mitochondrion 2016; 30:255-64. [PMID: 27566481 PMCID: PMC5023498 DOI: 10.1016/j.mito.2016.08.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/12/2016] [Accepted: 08/22/2016] [Indexed: 01/21/2023]
Abstract
The mitochondrial genome (mtDNA) is intimately linked to cellular and organismal health, as demonstrated by the fact that mutations in and depletion of mtDNA result in severe mitochondrial disease in humans. However, cells contain hundreds to thousands of copies of mtDNA, which provides genetic redundancy, and creates a threshold effect in which a large percentage of mtDNA must be lost prior to clinical pathogenesis. As certain pharmaceuticals and genetic mutations can result in depletion of mtDNA, and as many environmental toxicants target mitochondria, it is important to understand whether reduced mtDNA will sensitize an individual to toxicant exposure. Here, using ethidium bromide (EtBr), which preferentially inhibits mtDNA replication, we reduced mtDNA 35-55% in the in vivo model organism Caenorhabditis elegans. Chronic, lifelong, low-dose EtBr exposure did not disrupt nematode development or lifespan, and induced only mild alterations in mitochondrial respiration, while having no effect on steady-state ATP levels. Next, we exposed nematodes with reduced mtDNA to the known and suspected mitochondrial toxicants aflatoxin B1, arsenite, paraquat, rotenone or ultraviolet C radiation (UVC). EtBr pre-exposure resulted in mild sensitization of nematodes to UVC and arsenite, had no effect on AfB1 and paraquat, and provided some protection from rotenone toxicity. These mixed results provide a first line of evidence suggesting that reduced mtDNA content may sensitize an individual to certain environmental exposures.
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Affiliation(s)
- Anthony L Luz
- Nicholas School of the Environment, Box 90328, Duke University, Durham, NC 27708, United States.
| | - Joel N Meyer
- Nicholas School of the Environment, Box 90328, Duke University, Durham, NC 27708, United States.
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44
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Gitschlag BL, Kirby CS, Samuels DC, Gangula RD, Mallal SA, Patel MR. Homeostatic Responses Regulate Selfish Mitochondrial Genome Dynamics in C. elegans. Cell Metab 2016; 24:91-103. [PMID: 27411011 PMCID: PMC5287496 DOI: 10.1016/j.cmet.2016.06.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 05/27/2016] [Accepted: 06/13/2016] [Indexed: 02/08/2023]
Abstract
Mutant mitochondrial genomes (mtDNA) can be viewed as selfish genetic elements that persist in a state of heteroplasmy despite having potentially deleterious metabolic consequences. We sought to study regulation of selfish mtDNA dynamics. We establish that the large 3.1-kb deletion-bearing mtDNA variant uaDf5 is a selfish genome in Caenorhabditis elegans. Next, we show that uaDf5 mutant mtDNA replicates in addition to, not at the expense of, wild-type mtDNA. These data suggest the existence of a homeostatic copy-number control that is exploited by uaDf5 to "hitchhike" to high frequency. We also observe activation of the mitochondrial unfolded protein response (UPR(mt)) in uaDf5 animals. Loss of UPR(mt) causes a decrease in uaDf5 frequency, whereas its constitutive activation increases uaDf5 levels. UPR(mt) activation protects uaDf5 from mitophagy. Taken together, we propose that mtDNA copy-number control and UPR(mt) represent two homeostatic response mechanisms that play important roles in regulating selfish mitochondrial genome dynamics.
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Affiliation(s)
- Bryan L Gitschlag
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Interdisciplinary Graduate Program, Vanderbilt University, Nashville, TN 37232, USA
| | - Cait S Kirby
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Biological Sciences Graduate Program, Vanderbilt University, Nashville, TN 37232, USA
| | - David C Samuels
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN 37232, USA
| | - Rama D Gangula
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Simon A Mallal
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Institute for Immunology and Infectious Diseases, Murdoch University, Murdoch, WA 6150, Australia
| | - Maulik R Patel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.
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45
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Wernick RI, Estes S, Howe DK, Denver DR. Paths of Heritable Mitochondrial DNA Mutation and Heteroplasmy in Reference and gas-1 Strains of Caenorhabditis elegans. Front Genet 2016; 7:51. [PMID: 27148352 PMCID: PMC4829587 DOI: 10.3389/fgene.2016.00051] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/21/2016] [Indexed: 11/17/2022] Open
Abstract
Heteroplasmy—the presence of more than one mitochondrial DNA (mtDNA) sequence type in a cell, tissue, or individual—impacts human mitochondrial disease and numerous aging-related syndromes. Understanding the trans-generational dynamics of mtDNA is critical to understanding the underlying mechanisms of mitochondrial disease and evolution. We investigated mtDNA mutation and heteroplasmy using a set of wild-type (N2 strain) and mitochondrial electron transport chain (ETC) mutant (gas-1) mutant Caenorhabditis elegans mutation-accumulation (MA) lines. The N2 MA lines, derived from a previous experiment, were bottlenecked for 250 generations. The gas-1 MA lines were created for this study, and bottlenecked in the laboratory for up to 50 generations. We applied Illumina-MiSeq DNA sequencing to L1 larvae from five gas-1 MA lines and five N2 MA lines to detect and characterize mtDNA mutation and heteroplasmic inheritance patterns evolving under extreme drift. mtDNA copy number increased in both sets of MA lines: three-fold on average among the gas-1 MA lines and five-fold on average among N2 MA lines. Eight heteroplasmic single base substitution polymorphisms were detected in the gas-1 MA lines; only one was observed in the N2 MA lines. Heteroplasmy frequencies ranged broadly in the gas-1 MA lines, from as low as 2.3% to complete fixation (homoplasmy). An initially low-frequency (<5%) heteroplasmy discovered in the gas-1 progenitor was observed to fix in one gas-1 MA line, achieve higher frequency (37.4%) in another, and be lost in the other three lines. A similar low-frequency heteroplasmy was detected in the N2 progenitor, but was lost in all five N2 MA lines. We identified three insertion-deletion (indel) heteroplasmies in gas-1 MA lines and six indel variants in the N2 MA lines, most occurring at homopolymeric nucleotide runs. The observed bias toward accumulation of single nucleotide polymorphisms in gas-1 MA lines is consistent with the idea that impaired mitochondrial activity renders mtDNA more vulnerable to this type of mutation. The consistent increases in mtDNA copy number implies that extreme genetic drift provides a permissive environment for elevated organelle genome copy number in C. elegans reference and gas-1 strains. This study broadens our understanding of the heteroplasmic mitochondrial mutation process in a multicellular model organism.
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Affiliation(s)
- Riana I Wernick
- Department of Integrative Biology, Oregon State University Corvallis, OR, USA
| | - Suzanne Estes
- Department of Biology, Portland State University Portland, OR, USA
| | - Dana K Howe
- Department of Integrative Biology, Oregon State University Corvallis, OR, USA
| | - Dee R Denver
- Department of Integrative Biology, Oregon State University Corvallis, OR, USA
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46
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Gonzalez-Hunt CP, Rooney JP, Ryde IT, Anbalagan C, Joglekar R, Meyer JN. PCR-Based Analysis of Mitochondrial DNA Copy Number, Mitochondrial DNA Damage, and Nuclear DNA Damage. ACTA ACUST UNITED AC 2016; 67:20.11.1-20.11.25. [PMID: 26828332 DOI: 10.1002/0471140856.tx2011s67] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Because of the role that DNA damage and depletion play in human disease, it is important to develop and improve tools to assess these endpoints. This unit describes PCR-based methods to measure nuclear and mitochondrial DNA damage and copy number. Long amplicon quantitative polymerase chain reaction (LA-QPCR) is used to detect DNA damage by measuring the number of polymerase-inhibiting lesions present based on the amount of PCR amplification; real-time PCR (RT-PCR) is used to calculate genome content. In this unit, we provide step-by-step instructions to perform these assays in Homo sapiens, Mus musculus, Rattus norvegicus, Caenorhabditis elegans, Drosophila melanogaster, Danio rerio, Oryzias latipes, Fundulus grandis, and Fundulus heteroclitus, and discuss the advantages and disadvantages of these assays.
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Affiliation(s)
| | - John P Rooney
- Nicholas School of the Environment, Duke University, Durham, North Carolina
| | - Ian T Ryde
- Nicholas School of the Environment, Duke University, Durham, North Carolina
| | | | - Rashmi Joglekar
- Nicholas School of the Environment, Duke University, Durham, North Carolina
| | - Joel N Meyer
- Nicholas School of the Environment, Duke University, Durham, North Carolina
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47
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Pitayu L, Baruffini E, Rodier C, Rötig A, Lodi T, Delahodde A. Combined use of Saccharomyces cerevisiae, Caenorhabditis elegans and patient fibroblasts leads to the identification of clofilium tosylate as a potential therapeutic chemical against POLG-related diseases. Hum Mol Genet 2015; 25:715-27. [PMID: 26692522 DOI: 10.1093/hmg/ddv509] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 12/08/2015] [Indexed: 11/13/2022] Open
Abstract
Mitochondria are organelles that have their own DNA (mitochondrial DNA, mtDNA) whose maintenance is necessary for the majority of ATP production in eukaryotic cells. Defects in mtDNA maintenance or integrity are responsible for numerous diseases. The DNA polymerase γ (POLG) ensures proper mtDNA replication and repair. Mutations in POLG are a major cause of mitochondrial disorders including hepatic insufficiency, Alpers syndrome, progressive external ophthalmoplegia, sensory neuropathy and ataxia. Mutations in POLG are also associated with parkinsonism. To date, no effective therapy is available. Based on the conservation of mitochondrial function from yeast to human, we used Saccharomyces cerevisiae and Caenorhabditis elegans as first pass filters to identify a chemical that suppresses mtDNA instability in cultured fibroblasts of a POLG-deficient patient. We showed that this unsuspected compound, clofilium tosylate (CLO), belonging to a class of anti-arrhythmic agents, prevents mtDNA loss of all yeast mitochondrial polymerase mutants tested, improves behavior and mtDNA content of polg-1-deficient worms and increases mtDNA content of quiescent POLG-deficient fibroblasts. Furthermore, the mode of action of the drug seems conserved as CLO increases POLG steady-state level in yeast and human cells. Two other anti-arrhythmic agents (FDA-approved) sharing common pharmacological properties and chemical structure also show potential benefit for POLG deficiency in C. elegans. Our findings provide evidence of the first mtDNA-stabilizing compound that may be an effective pharmacological alternative for the treatment of POLG-related diseases.
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Affiliation(s)
- Laras Pitayu
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Enrico Baruffini
- Department of Life Sciences, University of Parma, Parco Area delle Scienze 11/a, I-43124 Parma, Italy and
| | - Celine Rodier
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Agnès Rötig
- INSERM UMR 1163, Laboratory of Genetics of Mitochondrial Disorders, Paris Descartes - Sorbonne Paris Cité University, Imagine Institute, 24 Boulevard du Montparnasse, Paris 75015, France
| | - Tiziana Lodi
- Department of Life Sciences, University of Parma, Parco Area delle Scienze 11/a, I-43124 Parma, Italy and
| | - Agnès Delahodde
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France,
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48
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Bratic A, Kauppila TE, Macao B, Grönke S, Siibak T, Stewart JB, Baggio F, Dols J, Partridge L, Falkenberg M, Wredenberg A, Larsson NG. Complementation between polymerase- and exonuclease-deficient mitochondrial DNA polymerase mutants in genomically engineered flies. Nat Commun 2015; 6:8808. [PMID: 26554610 DOI: 10.1038/ncomms9808] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/06/2015] [Indexed: 01/08/2023] Open
Abstract
Replication errors are the main cause of mitochondrial DNA (mtDNA) mutations and a compelling approach to decrease mutation levels would therefore be to increase the fidelity of the catalytic subunit (POLγA) of the mtDNA polymerase. Here we genomically engineer the tamas locus, encoding fly POLγA, and introduce alleles expressing exonuclease- (exo−) and polymerase-deficient (pol−) POLγA versions. The exo− mutant leads to accumulation of point mutations and linear deletions of mtDNA, whereas pol− mutants cause mtDNA depletion. The mutant tamas alleles are developmentally lethal but can complement each other in trans resulting in viable flies with clonally expanded mtDNA mutations. Reconstitution of human mtDNA replication in vitro confirms that replication is a highly dynamic process where POLγA goes on and off the template to allow complementation during proofreading and elongation. The created fly models are valuable tools to study germ line transmission of mtDNA and the pathophysiology of POLγA mutation disease. A key source of mitochondrial DNA mutations is errors introduced during genome replication. Here the authors create Drosophilia strains with separated elongation and proofreading capabilities to explore the dynamism of mitochondrial DNA replication.
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49
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Luz AL, Smith LL, Rooney JP, Meyer JN. Seahorse Xfe 24 Extracellular Flux Analyzer-Based Analysis of Cellular Respiration in Caenorhabditis elegans. Curr Protoc Toxicol 2015; 66:25.7.1-25.7.15. [PMID: 26523474 PMCID: PMC4632645 DOI: 10.1002/0471140856.tx2507s66] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Mitochondria are critical for their role in ATP production as well as multiple nonenergetic functions, and mitochondrial dysfunction is causal in myriad human diseases. Less well appreciated is the fact that mitochondria integrate environmental and intercellular as well as intracellular signals to modulate function. Because mitochondria function in an organismal milieu, there is need for assays capable of rapidly assessing mitochondrial health in vivo. Here, using the Seahorse XF(e) 24 Extracellular Flux Analyzer and the pharmacological inhibitors dicyclohexylcarbodiimide (DCCD, ATP synthase inhibitor), carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP, mitochondrial uncoupler), and sodium azide (cytochrome c oxidase inhibitor), we describe how to obtain in vivo measurements of the fundamental parameters [basal oxygen consumption rate (OCR), ATP-linked respiration, maximal OCR, spare respiratory capacity, and proton leak] of the mitochondrial respiratory chain in the model organism Caenorhabditis elegans.
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Affiliation(s)
- Anthony L Luz
- Nicholas School of the Environment, Duke University, Durham, North Carolina
| | - Latasha L Smith
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina
| | - John P Rooney
- Nicholas School of the Environment, Duke University, Durham, North Carolina
| | - Joel N Meyer
- Nicholas School of the Environment, Duke University, Durham, North Carolina
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50
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Rahn JJ, Bestman JE, Stackley KD, Chan SSL. Zebrafish lacking functional DNA polymerase gamma survive to juvenile stage, despite rapid and sustained mitochondrial DNA depletion, altered energetics and growth. Nucleic Acids Res 2015; 43:10338-52. [PMID: 26519465 PMCID: PMC4666367 DOI: 10.1093/nar/gkv1139] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 10/16/2015] [Indexed: 01/05/2023] Open
Abstract
DNA polymerase gamma (POLG) is essential for replication and repair of mitochondrial DNA (mtDNA). Mutations in POLG cause mtDNA instability and a diverse range of poorly understood human diseases. Here, we created a unique Polg animal model, by modifying polg within the critical and highly conserved polymerase domain in zebrafish. polg+/− offspring were indistinguishable from WT siblings in multiple phenotypic and biochemical measures. However, polg−/− mutants developed severe mtDNA depletion by one week post-fertilization (wpf), developed slowly and had regenerative defects, yet surprisingly survived up to 4 wpf. An in vivo mtDNA polymerase activity assay utilizing ethidium bromide (EtBr) to deplete mtDNA, showed that polg+/− and WT zebrafish fully recover mtDNA content two weeks post-EtBr removal. EtBr further reduced already low levels of mtDNA in polg−/− animals, but mtDNA content did not recover following release from EtBr. Despite significantly decreased respiration that corresponded with tissue-specific levels of mtDNA, polg−/− animals had WT levels of ATP and no increase in lactate. This zebrafish model of mitochondrial disease now provides unique opportunities for studying mtDNA instability from multiple angles, as polg−/− mutants can survive to juvenile stage, rather than lose viability in embryogenesis as seen in Polg mutant mice.
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Affiliation(s)
- Jennifer J Rahn
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Jennifer E Bestman
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Krista D Stackley
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Sherine S L Chan
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
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