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Dubie JJ, Katju V, Bergthorsson U. Dissecting the sequential evolution of a selfish mitochondrial genome in Caenorhabditis elegans. Heredity (Edinb) 2024:10.1038/s41437-024-00704-2. [PMID: 38969772 DOI: 10.1038/s41437-024-00704-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 06/24/2024] [Accepted: 06/25/2024] [Indexed: 07/07/2024] Open
Abstract
Mitochondrial genomes exist in a nested hierarchy of populations where mitochondrial variants are subject to genetic drift and selection at each level of organization, sometimes engendering conflict between different levels of selection, and between the nuclear and mitochondrial genomes. Deletion mutants in the Caenorhabditis elegans mitochondrial genome can reach high intracellular frequencies despite strongly detrimental effects on fitness. During a mutation accumulation (MA) experiment in C. elegans, a 499 bp deletion in ctb-1 rose to 90% frequency within cells while significantly reducing fitness. During the experiment, the deletion-bearing mtDNA acquired three additional mutations in nd5, namely two single insertion frameshift mutations in a homopolymeric run, and a base substitution. Despite an additional fitness cost of these secondary mutations, all deletion-bearing molecules contained the nd5 mutations at the termination of the MA experiment. The presence of mutant mtDNA was associated with increased mtDNA copy-number. Variation in mtDNA copy-number was greater in the MA lines than in a wildtype nuclear background, including a severe reduction in copy-number at one generational timepoint. Evolutionary replay experiments using different generations of the MA experiment as starting points suggests that two of the secondary mutations contribute to the proliferation of the original ctb-1 deletion by unknown mechanisms.
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Affiliation(s)
- Joseph J Dubie
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA
- Department of Integrative Biology, University of Texas, Austin, TX, USA
| | - Vaishali Katju
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA.
- Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 752 36, Uppsala, Sweden.
| | - Ulfar Bergthorsson
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA.
- Evolutionary Biology, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 752 36, Uppsala, Sweden.
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Olufs ZPG, Wassarman DA, Perouansky M. Stress Pathways Induced by Volatile Anesthetics and Failure of Preconditioning in a Mitochondrial Complex I Mutant. Anesthesiology 2024; 140:463-482. [PMID: 38118175 DOI: 10.1097/aln.0000000000004874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
BACKGROUND Carriers of mutations in the mitochondrial electron transport chain are at increased risk of anesthetic-induced neurotoxicity. To investigate the neurotoxicity mechanism and to test preconditioning as a protective strategy, this study used a Drosophila melanogaster model of Leigh syndrome. Model flies carried a mutation in ND23 (ND2360114) that encodes a mitochondrial electron transport chain complex I subunit. This study investigated why ND2360114 mutants become susceptible to lethal, oxygen-modulated neurotoxicity within 24 h of exposure to isoflurane but not sevoflurane. METHODS This study used transcriptomics and quantitative real-time reverse transcription polymerase chain reaction to identify genes that are differentially expressed in ND2360114 but not wild-type fly heads at 30 min after exposure to high- versus low-toxicity conditions. This study also subjected ND2360114 flies to diverse stressors before isoflurane exposure to test whether isoflurane toxicity could be diminished by preconditioning. RESULTS The ND2360114 mutation had a greater effect on isoflurane- than sevoflurane-mediated changes in gene expression. Isoflurane and sevoflurane did not affect expression of heat shock protein (Hsp) genes (Hsp22, Hsp27, and Hsp68) in wild-type flies, but isoflurane substantially increased expression of these genes in ND2360114 mutant flies. Furthermore, isoflurane and sevoflurane induced expression of oxidative (GstD1 and GstD2) and xenobiotic (Cyp6a8 and Cyp6a14) stress genes to a similar extent in wild-type flies, but the effect of isoflurane was largely reduced in ND2360114 flies. In addition, activating stress response pathways by pre-exposure to anesthetics, heat shock, hyperoxia, hypoxia, or oxidative stress did not suppress isoflurane-induced toxicity in ND2360114 mutant flies. CONCLUSIONS Mutation of a mitochondrial electron transport chain complex I subunit generates differential effects of isoflurane and sevoflurane on gene expression that may underlie their differential effects on neurotoxicity. Additionally, the mutation produces resistance to preconditioning by stresses that protect the brain in other contexts. Therefore, complex I activity modifies molecular and physiologic effects of anesthetics in an anesthetic-specific manner. EDITOR’S PERSPECTIVE
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Affiliation(s)
- Zachariah P G Olufs
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - David A Wassarman
- Department of Medical Genetics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Misha Perouansky
- Department of Anesthesiology, School of Medicine and Public Health and Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin
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3
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Estes S, Dietz ZP, Katju V, Bergthorsson U. Evolutionary codependency: insights into the mitonuclear interaction landscape from experimental and wild Caenorhabditis nematodes. Curr Opin Genet Dev 2023; 81:102081. [PMID: 37421904 DOI: 10.1016/j.gde.2023.102081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 07/10/2023]
Abstract
Aided by new technologies, the upsurgence of research into mitochondrial genome biology during the past 15 years suggests that we have misunderstood, and perhaps dramatically underestimated, the ongoing biological and evolutionary significance of our long-time symbiotic partner. While we have begun to scratch the surface of several topics, many questions regarding the nature of mutation and selection in the mitochondrial genome, and the nature of its relationship to the nuclear genome, remain unanswered. Although best known for their contributions to studies of developmental and aging biology, Caenorhabditis nematodes are increasingly recognized as excellent model systems to advance understanding in these areas. We review recent discoveries with relevance to mitonuclear coevolution and conflict and offer several fertile areas for future work.
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Affiliation(s)
- Suzanne Estes
- Portland State University, Department of Biology, Portland, OR, USA.
| | - Zachary P Dietz
- Portland State University, Department of Biology, Portland, OR, USA
| | - Vaishali Katju
- Uppsala University, Department of Ecology and Genetics, 752 36 Uppsala, Sweden
| | - Ulfar Bergthorsson
- Uppsala University, Department of Ecology and Genetics, 752 36 Uppsala, Sweden
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Perouansky M, Johnson-Schlitz D, Sedensky MM, Morgan PG. A primordial target: Mitochondria mediate both primary and collateral anesthetic effects of volatile anesthetics. Exp Biol Med (Maywood) 2023; 248:545-552. [PMID: 37208922 PMCID: PMC10350799 DOI: 10.1177/15353702231165025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023] Open
Abstract
One of the unsolved mysteries of medicine is how do volatile anesthetics (VAs) cause a patient to reversibly lose consciousness. In addition, identifying mechanisms for the collateral effects of VAs, including anesthetic-induced neurotoxicity (AiN) and anesthetic preconditioning (AP), has proven challenging. Multiple classes of molecules (lipids, proteins, and water) have been considered as potential VA targets, but recently proteins have received the most attention. Studies targeting neuronal receptors or ion channels had limited success in identifying the critical targets of VAs mediating either the phenotype of "anesthesia" or their collateral effects. Recent studies in both nematodes and fruit flies may provide a paradigm shift by suggesting that mitochondria may harbor the upstream molecular switch activating both primary and collateral effects. The disruption of a specific step of electron transfer within the mitochondrion causes hypersensitivity to VAs, from nematodes to Drosophila and to humans, while also modulating the sensitivity to collateral effects. The downstream effects from mitochondrial inhibition are potentially legion, but inhibition of presynaptic neurotransmitter cycling appears to be specifically sensitive to the mitochondrial effects. These findings are perhaps of even broader interest since two recent reports indicate that mitochondrial damage may well underlie neurotoxic and neuroprotective effects of VAs in the central nervous system (CNS). It is, therefore, important to understand how anesthetics interact with mitochondria to affect CNS function, not just for the desired facets of general anesthesia but also for significant collateral effects, both harmful and beneficial. A tantalizing possibility exists that both the primary (anesthesia) and secondary (AiN, AP) mechanisms may at least partially overlap in the mitochondrial electron transport chain (ETC).
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Affiliation(s)
- Misha Perouansky
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53792, USA
- Laboratory of Genetics, School of Medicine and Public Health and College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Dena Johnson-Schlitz
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Margaret M Sedensky
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA 98101, USA
| | - Philip G Morgan
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA 98101, USA
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Jung S, Zimin PI, Woods CB, Kayser EB, Haddad D, Reczek CR, Nakamura K, Ramirez JM, Sedensky MM, Morgan PG. Isoflurane inhibition of endocytosis is an anesthetic mechanism of action. Curr Biol 2022; 32:3016-3032.e3. [PMID: 35688155 PMCID: PMC9329204 DOI: 10.1016/j.cub.2022.05.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 03/30/2022] [Accepted: 05/13/2022] [Indexed: 10/18/2022]
Abstract
The mechanisms of volatile anesthetic action remain among the most perplexing mysteries of medicine. Across phylogeny, volatile anesthetics selectively inhibit mitochondrial complex I, and they also depress presynaptic excitatory signaling. To explore how these effects are linked, we studied isoflurane effects on presynaptic vesicle cycling and ATP levels in hippocampal cultured neurons from wild-type and complex I mutant (Ndufs4(KO)) mice. To bypass complex I, we measured isoflurane effects on anesthetic sensitivity in mice expressing NADH dehydrogenase (NDi1). Endocytosis in physiologic concentrations of glucose was delayed by effective behavioral concentrations of isoflurane in both wild-type (τ [unexposed] 44.8 ± 24.2 s; τ [exposed] 116.1 ± 28.1 s; p < 0.01) and Ndufs4(KO) cultures (τ [unexposed] 67.6 ± 16.0 s; τ [exposed] 128.4 ± 42.9 s; p = 0.028). Increasing glucose, to enhance glycolysis and increase ATP production, led to maintenance of both ATP levels and endocytosis (τ [unexposed] 28.0 ± 14.4; τ [exposed] 38.2 ± 5.7; reducing glucose worsened ATP levels and depressed endocytosis (τ [unexposed] 85.4 ± 69.3; τ [exposed] > 1,000; p < 0.001). The block in recycling occurred at the level of reuptake of synaptic vesicles into the presynaptic cell. Expression of NDi1 in wild-type mice caused behavioral resistance to isoflurane for tail clamp response (EC50 Ndi1(-) 1.27% ± 0.14%; Ndi1(+) 1.55% ± 0.13%) and halothane (EC50 Ndi1(-) 1.20% ± 0.11%; Ndi1(+) 1.46% ± 0.10%); expression of NDi1 in neurons improved hippocampal function, alleviated inhibition of presynaptic recycling, and increased ATP levels during isoflurane exposure. The clear alignment of cell culture data to in vivo phenotypes of both isoflurane-sensitive and -resistant mice indicates that inhibition of mitochondrial complex I is a primary mechanism of action of volatile anesthetics.
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Affiliation(s)
- Sangwook Jung
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Pavel I Zimin
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA
| | - Christian B Woods
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Ernst-Bernhard Kayser
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Dominik Haddad
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Colleen R Reczek
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Ken Nakamura
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Neurological Surgery, University of Washington, Seattle, WA 98105, USA
| | - Margaret M Sedensky
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA
| | - Philip G Morgan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA.
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Jung Y, Artan M, Kim N, Yeom J, Hwang AB, Jeong DE, Altintas Ö, Seo K, Seo M, Lee D, Hwang W, Lee Y, Sohn J, Kim EJE, Ju S, Han SK, Nam HJ, Adams L, Ryu Y, Moon DJ, Kang C, Yoo JY, Park SK, Ha CM, Hansen M, Kim S, Lee C, Park SY, Lee SJV. MON-2, a Golgi protein, mediates autophagy-dependent longevity in Caenorhabditis elegans. SCIENCE ADVANCES 2021; 7:eabj8156. [PMID: 34860542 PMCID: PMC8641931 DOI: 10.1126/sciadv.abj8156] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/14/2021] [Indexed: 06/02/2023]
Abstract
The Golgi apparatus plays a central role in trafficking cargoes such as proteins and lipids. Defects in the Golgi apparatus lead to various diseases, but its role in organismal longevity is largely unknown. Using a quantitative proteomic approach, we found that a Golgi protein, MON-2, was up-regulated in long-lived Caenorhabditis elegans mutants with mitochondrial respiration defects and was required for their longevity. Similarly, we showed that DOP1/PAD-1, which acts with MON-2 to traffic macromolecules between the Golgi and endosome, contributed to the longevity of respiration mutants. Furthermore, we demonstrated that MON-2 was required for up-regulation of autophagy, a longevity-associated recycling process, by activating the Atg8 ortholog GABARAP/LGG-1 in C. elegans. Consistently, we showed that mammalian MON2 activated GABARAPL2 through physical interaction, which increased autophagic flux in mammalian cells. Thus, the evolutionarily conserved role of MON2 in trafficking between the Golgi and endosome is an integral part of autophagy-mediated longevity.
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Affiliation(s)
- Yoonji Jung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Murat Artan
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Nari Kim
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Jeonghun Yeom
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Ara B. Hwang
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Dae-Eun Jeong
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Özlem Altintas
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Keunhee Seo
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Mihwa Seo
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Dongyeop Lee
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Wooseon Hwang
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Yujin Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Jooyeon Sohn
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Eun Ji E. Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Sungeun Ju
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Seong Kyu Han
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Hyun-Jun Nam
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Linnea Adams
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Youngjae Ryu
- Research Division and Brain Research Core Facilities of Korea Brain Research Institute, Daegu 41068, South Korea
| | - Dong Jin Moon
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Chanhee Kang
- School of Biological Sciences, College of Natural Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Joo-Yeon Yoo
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Sang Ki Park
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Chang Man Ha
- Research Division and Brain Research Core Facilities of Korea Brain Research Institute, Daegu 41068, South Korea
| | - Malene Hansen
- Development, Aging, and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Sanguk Kim
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Cheolju Lee
- Center for Theragnosis, Korea Institute of Science and Technology, Seoul 02792, South Korea
| | - Seung-Yeol Park
- Department of Life Sciences, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, South Korea
| | - Seung-Jae V. Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
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Knapp-Wilson A, Pereira GC, Buzzard E, Ford HC, Richardson A, Corey RA, Neal C, Verkade P, Halestrap AP, Gold VAM, Kuwabara PE, Collinson I. Maintenance of complex I and its supercomplexes by NDUF-11 is essential for mitochondrial structure, function and health. J Cell Sci 2021; 134:jcs258399. [PMID: 34106255 PMCID: PMC8277142 DOI: 10.1242/jcs.258399] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 05/28/2021] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial supercomplexes form around a conserved core of monomeric complex I and dimeric complex III; wherein a subunit of the former, NDUFA11, is conspicuously situated at the interface. We identified nduf-11 (B0491.5) as encoding the Caenorhabditis elegans homologue of NDUFA11. Animals homozygous for a CRISPR-Cas9-generated knockout allele of nduf-11 arrested at the second larval (L2) development stage. Reducing (but not eliminating) expression using RNAi allowed development to adulthood, enabling characterisation of the consequences: destabilisation of complex I and its supercomplexes and perturbation of respiratory function. The loss of NADH dehydrogenase activity was compensated by enhanced complex II activity, with the potential for detrimental reactive oxygen species (ROS) production. Cryo-electron tomography highlighted aberrant morphology of cristae and widening of both cristae junctions and the intermembrane space. The requirement of NDUF-11 for balanced respiration, mitochondrial morphology and development presumably arises due to its involvement in complex I and supercomplex maintenance. This highlights the importance of respiratory complex integrity for health and the potential for its perturbation to cause mitochondrial disease. This article has an associated First Person interview with Amber Knapp-Wilson, joint first author of the paper.
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Affiliation(s)
| | | | - Emma Buzzard
- Living Systems Institute, Stocker Road, University of Exeter, Exeter EX4 4QD, UK
- College of Life and Environmental Sciences,Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Holly C. Ford
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | | | - Robin A. Corey
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Chris Neal
- Wolfson Bioimaging Facility, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Paul Verkade
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | | | - Vicki A. M. Gold
- Living Systems Institute, Stocker Road, University of Exeter, Exeter EX4 4QD, UK
- College of Life and Environmental Sciences,Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | | | - Ian Collinson
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
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Hsieh VC, Niezgoda J, Sedensky MM, Hoppel CL, Morgan PG. Anesthetic Hypersensitivity in a Case-Controlled Series of Patients With Mitochondrial Disease. Anesth Analg 2021; 133:924-932. [PMID: 33591116 DOI: 10.1213/ane.0000000000005430] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Children with mitochondrial disease undergo anesthesia for a wide array of surgical procedures. However, multiple medications used for their perioperative care can affect mitochondrial function. Defects in function of the mitochondrial electron transport chain (ETC) can lead to a profound hypersensitivity to sevoflurane in children. We studied the sensitivities to sevoflurane, during mask induction and maintenance of general anesthesia, in children presenting for muscle biopsies for diagnosis of mitochondrial disease. METHODS In this multicenter study, 91 children, aged 6 months to 16 years, presented to the operating room for diagnostic muscle biopsy for presumptive mitochondrial disease. General anesthesia was induced by a slow increase of inhaled sevoflurane concentration. The primary end point, end-tidal (ET) sevoflurane necessary to achieve a bispectral index (BIS) of 60, was recorded. Secondary end points were maximal sevoflurane used to maintain a BIS between 40 and 60 during the case, and maximum and minimum heart rate and blood pressures. After induction, general anesthesia was maintained according to the preferences of the providers directing the cases. Primary data were analyzed comparing data from patients with complex I deficiencies to other groups using nonparametric statistics in SPSS v.27. RESULTS The median sevoflurane concentration to reach BIS of 60 during inductions (ET sevoflurane % [BIS = 60]) was significantly lower for patients with complex I defects (0.98%; 95% confidence interval [CI], 0.5-1.4) compared to complex II (1.95%; 95% CI, 1.2-2.7; P < .001), complex III (2.0%; 95% CI, 0.7-3.5; P < .001), complex IV (2.0%; 95% CI, 1.7-3.2; P < .001), and normal groups (2.2%; 95% CI, 1.8-3.0; P < .001). The sevoflurane sensitivities of complex I patients did not reach significance when compared to patients diagnosed with mitochondrial disease but without an identifiable ETC abnormality (P = .172). Correlation of complex I activity with ET sevoflurane % (BIS = 60) gave a Spearman's coefficient of 0.505 (P < .001). The differences in sensitivities between groups were less during the maintenance of the anesthetic than during induction. CONCLUSIONS The data indicate that patients with complex I dysfunction are hypersensitive to sevoflurane compared to normal patients. Hypersensitivity was less common in patients presenting with other mitochondrial defects or without a mitochondrial diagnosis.
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Affiliation(s)
- Vincent C Hsieh
- From the Department of Anesthesiology and Perioperative Medicine, University of Washington and Seattle Children's Hospital, Seattle, Washington
| | - Julie Niezgoda
- Department of Pediatric Anesthesiology, Cleveland Clinic, Cleveland, Ohio
| | - Margaret M Sedensky
- From the Department of Anesthesiology and Perioperative Medicine, University of Washington and Seattle Children's Hospital, Seattle, Washington
| | - Charles L Hoppel
- Department of Pharmacology and Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Philip G Morgan
- From the Department of Anesthesiology and Perioperative Medicine, University of Washington and Seattle Children's Hospital, Seattle, Washington
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9
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Alcántar-Fernández J, González-Maciel A, Reynoso-Robles R, Pérez Andrade ME, Hernández-Vázquez ADJ, Velázquez-Arellano A, Miranda-Ríos J. High-glucose diets induce mitochondrial dysfunction in Caenorhabditis elegans. PLoS One 2019; 14:e0226652. [PMID: 31846489 PMCID: PMC6917275 DOI: 10.1371/journal.pone.0226652] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 11/29/2019] [Indexed: 01/20/2023] Open
Abstract
Glucose is an important nutrient that dictates the development, fertility and lifespan of all organisms. In humans, a deficit in its homeostatic control might lead to hyperglucemia and the development of obesity and type 2 diabetes, which show a decreased ability to respond to and metabolize glucose. Previously, we have reported that high-glucose diets (HGD) induce alterations in triglyceride content, body size, progeny, and the mRNA accumulation of key regulators of carbohydrate and lipid metabolism, and longevity in Caenorhabditis elegans (PLoS ONE 13(7): e0199888). Herein, we show that increasing amounts of glucose in the diet induce the swelling of both mitochondria in germ and muscle cells. Additionally, HGD alter the enzymatic activities of the different respiratory complexes in an intricate pattern. Finally, we observed a downregulation of ceramide synthases (hyl-1 and hyl-2) and antioxidant genes (gcs-1 and gst-4), while mitophagy genes (pink-1 and dct-1) were upregulated, probably as part of a mitohormetic mechanism in response to glucose toxicity.
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Affiliation(s)
- Jonathan Alcántar-Fernández
- Programa de Doctorado en Ciencias Biomédicas, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
- Unidad de Genética de la Nutrición, Depto. de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, UNAM e Instituto Nacional de Pediatría, Ciudad de México, México
| | - Angélica González-Maciel
- Laboratorio de Morfología Celular y Tisular, Instituto Nacional de Pediatría, Ciudad de México, México
| | - Rafael Reynoso-Robles
- Laboratorio de Morfología Celular y Tisular, Instituto Nacional de Pediatría, Ciudad de México, México
| | - Martha Elva Pérez Andrade
- Unidad de Genética de la Nutrición, Depto. de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, UNAM e Instituto Nacional de Pediatría, Ciudad de México, México
| | - Alain de J. Hernández-Vázquez
- Unidad de Genética de la Nutrición, Depto. de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, UNAM e Instituto Nacional de Pediatría, Ciudad de México, México
| | - Antonio Velázquez-Arellano
- Unidad de Genética de la Nutrición, Depto. de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, UNAM e Instituto Nacional de Pediatría, Ciudad de México, México
| | - Juan Miranda-Ríos
- Unidad de Genética de la Nutrición, Depto. de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, UNAM e Instituto Nacional de Pediatría, Ciudad de México, México
- * E-mail:
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10
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Chuaijit S, Boonyatistan W, Boonchuay P, Metheetrairut C, Suthammarak W. Identification of a novel mitochondrial complex I assembly factor ACDH-12 in Caenorhabditis elegans. Mitochondrion 2019. [DOI: 10.1016/j.mito.2018.02.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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11
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Aw WC, Towarnicki SG, Melvin RG, Youngson NA, Garvin MR, Hu Y, Nielsen S, Thomas T, Pickford R, Bustamante S, Vila-Sanjurjo A, Smyth GK, Ballard JWO. Genotype to phenotype: Diet-by-mitochondrial DNA haplotype interactions drive metabolic flexibility and organismal fitness. PLoS Genet 2018; 14:e1007735. [PMID: 30399141 PMCID: PMC6219761 DOI: 10.1371/journal.pgen.1007735] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 10/02/2018] [Indexed: 02/07/2023] Open
Abstract
Diet may be modified seasonally or by biogeographic, demographic or cultural shifts. It can differentially influence mitochondrial bioenergetics, retrograde signalling to the nuclear genome, and anterograde signalling to mitochondria. All these interactions have the potential to alter the frequencies of mtDNA haplotypes (mitotypes) in nature and may impact human health. In a model laboratory system, we fed four diets varying in Protein: Carbohydrate (P:C) ratio (1:2, 1:4, 1:8 and 1:16 P:C) to four homoplasmic Drosophila melanogaster mitotypes (nuclear genome standardised) and assayed their frequency in population cages. When fed a high protein 1:2 P:C diet, the frequency of flies harbouring Alstonville mtDNA increased. In contrast, when fed the high carbohydrate 1:16 P:C food the incidence of flies harbouring Dahomey mtDNA increased. This result, driven by differences in larval development, was generalisable to the replacement of the laboratory diet with fruits having high and low P:C ratios, perturbation of the nuclear genome and changes to the microbiome. Structural modelling and cellular assays suggested a V161L mutation in the ND4 subunit of complex I of Dahomey mtDNA was mildly deleterious, reduced mitochondrial functions, increased oxidative stress and resulted in an increase in larval development time on the 1:2 P:C diet. The 1:16 P:C diet triggered a cascade of changes in both mitotypes. In Dahomey larvae, increased feeding fuelled increased β-oxidation and the partial bypass of the complex I mutation. Conversely, Alstonville larvae upregulated genes involved with oxidative phosphorylation, increased glycogen metabolism and they were more physically active. We hypothesise that the increased physical activity diverted energy from growth and cell division and thereby slowed development. These data further question the use of mtDNA as an assumed neutral marker in evolutionary and population genetic studies. Moreover, if humans respond similarly, we posit that individuals with specific mtDNA variations may differentially metabolise carbohydrates, which has implications for a variety of diseases including cardiovascular disease, obesity, and perhaps Parkinson's Disease.
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Affiliation(s)
- Wen C. Aw
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Samuel G. Towarnicki
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Richard G. Melvin
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Neil A. Youngson
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Michael R. Garvin
- School of Biological Sciences, Washington State University, Pullman, Washington, United States of America
| | - Yifang Hu
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
| | - Shaun Nielsen
- Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Torsten Thomas
- Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Russell Pickford
- Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Center, The University of New South Wales, Sydney, NSW, Australia
| | - Sonia Bustamante
- Bioanalytical Mass Spectrometry Facility, Mark Wainwright Analytical Center, The University of New South Wales, Sydney, NSW, Australia
| | - Antón Vila-Sanjurjo
- Grupo GIBE, Bioloxía Celular e Molecular, Facultade de Ciencias, Universidade da Coruña (UDC), Campus Zapateira s/n, A Coruña, Spain
| | - Gordon K. Smyth
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
- School of Mathematics and Statistics, The University of Melbourne, Melbourne, Victoria, Australia
| | - J. William O. Ballard
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
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12
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Genetic inhibition of an ATP synthase subunit extends lifespan in C. elegans. Sci Rep 2018; 8:14836. [PMID: 30287841 PMCID: PMC6172204 DOI: 10.1038/s41598-018-32025-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 08/31/2018] [Indexed: 12/16/2022] Open
Abstract
Mild inhibition of mitochondrial respiration leads to longevity. Disruption of mitochondrial respiratory components extends lifespan in Caenorhabditis elegans, but the effects appear to be complex and the underlying mechanism for lifespan regulation by mitochondrial respiratory genes is still not fully understood. Here, we investigated the role of Y82E9BR.3, a worm homolog of the ATP synthase subunit C, in modulating longevity in C. elegans. We found that the Y82E9BR.3 protein is localized in mitochondria and expressed in various tissues throughout development. RNAi knockdown of Y82E9BR.3 extends lifespan, decreases the accumulation of lipofuscin, and affects various physiological processes, including development delay, reproduction impairment and slow behavior. Further tissue-specific RNAi analysis showed that the intestine is a crucial organ for the longevity effects conferred by Y82E9BR.3 RNAi. Moreover, we demonstrated that lifespan extension by Y82E9BR.3 RNAi is associated with reduced mitochondrial function, as well as the suppression of complex I activity in mitochondria. Unexpectedly, Y82E9BR.3 RNAi knock down did not influence the whole-worm ATP level. Our findings first reveal the crucial role of Y82E9BR.3 in mitochondrial function and the underlying mechanism of how Y82E9BR.3 regulates lifespan in C. elegans.
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13
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Zimin PI, Woods CB, Kayser EB, Ramirez JM, Morgan PG, Sedensky MM. Isoflurane disrupts excitatory neurotransmitter dynamics via inhibition of mitochondrial complex I. Br J Anaesth 2018; 120:1019-1032. [PMID: 29661379 DOI: 10.1016/j.bja.2018.01.036] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/08/2018] [Accepted: 02/09/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The mechanisms of action of volatile anaesthetics are unclear. Volatile anaesthetics selectively inhibit complex I in the mitochondrial respiratory chain. Mice in which the mitochondrial complex I subunit NDUFS4 is knocked out [Ndufs4(KO)] either globally or in glutamatergic neurons are hypersensitive to volatile anaesthetics. The volatile anaesthetic isoflurane selectively decreases the frequency of spontaneous excitatory events in hippocampal slices from Ndufs4(KO) mice. METHODS Complex I inhibition by isoflurane was assessed with a Clark electrode. Synaptic function was measured by stimulating Schaffer collateral fibres and recording field potentials in the hippocampus CA1 region. RESULTS Isoflurane specifically inhibits complex I dependent respiration at lower concentrations in mitochondria from Ndufs4(KO) than from wild-type mice. In hippocampal slices, after high frequency stimulation to increase energetic demand, short-term synaptic potentiation is less in KO compared with wild-type mice. After high frequency stimulation, both Ndufs4(KO) and wild-type hippocampal slices exhibit striking synaptic depression in isoflurane at twice the 50% effective concentrations (EC50). The pattern of synaptic depression by isoflurane indicates a failure in synaptic vesicle recycling. Application of a selective A1 adenosine receptor antagonist partially eliminates isoflurane-induced short-term depression in both wild-type and Ndufs4(KO) slices, implicating an additional mitochondria-dependent effect on exocytosis. When mitochondria are the sole energy source, isoflurane completely eliminates synaptic output in both mutant and wild-type mice at twice the (EC50) for anaesthesia. CONCLUSIONS Volatile anaesthetics directly inhibit mitochondrial complex I as a primary target, limiting synaptic ATP production, and excitatory vesicle endocytosis and exocytosis.
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Affiliation(s)
- P I Zimin
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA.
| | - C B Woods
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - E B Kayser
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - J M Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Neurological Surgery, University of Washington, Seattle, WA, USA
| | - P G Morgan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
| | - M M Sedensky
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
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14
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Solution NMR structure of yeast Rcf1, a protein involved in respiratory supercomplex formation. Proc Natl Acad Sci U S A 2018; 115:3048-3053. [PMID: 29507228 DOI: 10.1073/pnas.1712061115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Saccharomyces cerevisiae respiratory supercomplex factor 1 (Rcf1) protein is located in the mitochondrial inner membrane where it is involved in formation of supercomplexes composed of respiratory complexes III and IV. We report the solution structure of Rcf1, which forms a dimer in dodecylphosphocholine (DPC) micelles, where each monomer consists of a bundle of five transmembrane (TM) helices and a short flexible soluble helix (SH). Three TM helices are unusually charged and provide the dimerization interface consisting of 10 putative salt bridges, defining a "charge zipper" motif. The dimer structure is supported by molecular dynamics (MD) simulations in DPC, although the simulations show a more dynamic dimer interface than the NMR data. Furthermore, CD and NMR data indicate that Rcf1 undergoes a structural change when reconstituted in liposomes, which is supported by MD data, suggesting that the dimer structure is unstable in a planar membrane environment. Collectively, these data indicate a dynamic monomer-dimer equilibrium. Furthermore, the Rcf1 dimer interacts with cytochrome c, suggesting a role as an electron-transfer bridge between complexes III and IV. The Rcf1 structure will help in understanding its functional roles at a molecular level.
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15
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van der Bliek AM, Sedensky MM, Morgan PG. Cell Biology of the Mitochondrion. Genetics 2017; 207:843-871. [PMID: 29097398 PMCID: PMC5676242 DOI: 10.1534/genetics.117.300262] [Citation(s) in RCA: 244] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 09/05/2017] [Indexed: 01/19/2023] Open
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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16
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Combined Respiratory Chain Deficiency and UQCC2 Mutations in Neonatal Encephalomyopathy: Defective Supercomplex Assembly in Complex III Deficiencies. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:7202589. [PMID: 28804536 PMCID: PMC5540226 DOI: 10.1155/2017/7202589] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/22/2017] [Accepted: 06/04/2017] [Indexed: 11/17/2022]
Abstract
Vertebrate respiratory chain complex III consists of eleven subunits. Mutations in five subunits either mitochondrial (MT-CYB) or nuclear (CYC1, UQCRC2, UQCRB, and UQCRQ) encoded have been reported. Defects in five further factors for assembly (TTC19, UQCC2, and UQCC3) or iron-sulphur cluster loading (BCS1L and LYRM7) cause complex III deficiency. Here, we report a second patient with UQCC2 deficiency. This girl was born prematurely; pregnancy was complicated by intrauterine growth retardation and oligohydramnios. She presented with respiratory distress syndrome, developed epileptic seizures progressing to status epilepticus, and died at day 33. She had profound lactic acidosis and elevated urinary pyruvate. Exome sequencing revealed two homozygous missense variants in UQCC2, leading to a severe reduction of UQCC2 protein. Deficiency of complexes I and III was found enzymatically and on the protein level. A review of the literature on genetically distinct complex III defects revealed that, except TTC19 deficiency, the biochemical pattern was very often a combined respiratory chain deficiency. Besides complex III, typically, complex I was decreased, in some cases complex IV. In accordance with previous observations, the presence of assembled complex III is required for the stability or assembly of complexes I and IV, which might be related to respirasome/supercomplex formation.
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17
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Dues DJ, Schaar CE, Johnson BK, Bowman MJ, Winn ME, Senchuk MM, Van Raamsdonk JM. Uncoupling of oxidative stress resistance and lifespan in long-lived isp-1 mitochondrial mutants in Caenorhabditis elegans. Free Radic Biol Med 2017; 108:362-373. [PMID: 28392283 PMCID: PMC5493208 DOI: 10.1016/j.freeradbiomed.2017.04.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 02/24/2017] [Accepted: 04/02/2017] [Indexed: 12/19/2022]
Abstract
Mutations affecting components of the mitochondrial electron transport chain have been shown to increase lifespan in multiple species including the worm Caenorhabditis elegans. While it was originally proposed that decreased generation of reactive oxygen species (ROS) resulting from lower rates of electron transport could account for the observed increase in lifespan, recent evidence indicates that ROS levels are increased in at least some of these long-lived mitochondrial mutants. Here, we show that the long-lived mitochondrial mutant isp-1 worms have increased resistance to oxidative stress. Our results suggest that elevated ROS levels in isp-1 worms cause the activation of multiple stress-response pathways including the mitochondrial unfolded protein response, the SKN-1-mediated stress response, and the hypoxia response. In addition, these worms have increased expression of specific antioxidant enzymes, including a marked upregulation of the inducible superoxide dismutase genes sod-3 and sod-5. Examining the contribution of sod-3 and sod-5 to the oxidative stress resistance in isp-1 worms revealed that loss of either of these genes increased resistance to oxidative stress, but not other forms of stress. Deletion of sod-3 or sod-5 decreased the lifespan of isp-1 worms and further exacerbated their slow physiologic rates. Thus, while deletion of sod-3 and sod-5 genes has little impact on stress resistance, physiologic rates or lifespan in wild-type worms, these genes are required for the longevity of isp-1 worms. Overall, this work shows that the increased resistance to oxidative stress in isp-1 worms does not account for their longevity, and that resistance to oxidative stress can be experimentally dissociated from lifespan.
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Affiliation(s)
- Dylan J Dues
- Laboratory of Aging and Neurodegenerative Disease (LAND), Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Claire E Schaar
- Laboratory of Aging and Neurodegenerative Disease (LAND), Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Benjamin K Johnson
- Bioinformatics and Biostatistics Core, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Megan J Bowman
- Bioinformatics and Biostatistics Core, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Mary E Winn
- Bioinformatics and Biostatistics Core, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Megan M Senchuk
- Laboratory of Aging and Neurodegenerative Disease (LAND), Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Jeremy M Van Raamsdonk
- Laboratory of Aging and Neurodegenerative Disease (LAND), Center for Neurodegenerative Science, Van Andel Research Institute, Grand Rapids, MI 49503, USA; Department of Translational Science and Molecular Medicine, Michigan State University, Grand Rapids, MI 49503, USA; Department of Genetics, Michigan State University, East Lansing, MI 48824, USA.
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18
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Munkácsy E, Khan MH, Lane RK, Borror MB, Park JH, Bokov AF, Fisher AL, Link CD, Rea SL. DLK-1, SEK-3 and PMK-3 Are Required for the Life Extension Induced by Mitochondrial Bioenergetic Disruption in C. elegans. PLoS Genet 2016; 12:e1006133. [PMID: 27420916 PMCID: PMC4946786 DOI: 10.1371/journal.pgen.1006133] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 05/27/2016] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial dysfunction underlies numerous age-related pathologies. In an effort to uncover how the detrimental effects of mitochondrial dysfunction might be alleviated, we examined how the nematode C. elegans not only adapts to disruption of the mitochondrial electron transport chain, but in many instances responds with extended lifespan. Studies have shown various retrograde responses are activated in these animals, including the well-studied ATFS-1-dependent mitochondrial unfolded protein response (UPRmt). Such processes fall under the greater rubric of cellular surveillance mechanisms. Here we identify a novel p38 signaling cascade that is required to extend life when the mitochondrial electron transport chain is disrupted in worms, and which is blocked by disruption of the Mitochondrial-associated Degradation (MAD) pathway. This novel cascade is defined by DLK-1 (MAP3K), SEK-3 (MAP2K), PMK-3 (MAPK) and the reporter gene Ptbb-6::GFP. Inhibition of known mitochondrial retrograde responses does not alter induction of Ptbb-6::GFP, instead induction of this reporter often occurs in counterpoint to activation of SKN-1, which we show is under the control of ATFS-1. In those mitochondrial bioenergetic mutants which activate Ptbb-6::GFP, we find that dlk-1, sek-3 and pmk-3 are all required for their life extension.
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Affiliation(s)
- Erin Munkácsy
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Cellular & Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Maruf H. Khan
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Medicine (Division of Geriatrics, Gerontology, and Palliative Medicine), University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Rebecca K. Lane
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Megan B. Borror
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Jae H. Park
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Alex F. Bokov
- Department of Epidemiology and Biostatistics, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Alfred L. Fisher
- Department of Medicine (Division of Geriatrics, Gerontology, and Palliative Medicine), University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Geriatric Research, Education and Clinical Center, South Texas VA Health Care System, San Antonio, Texas, United States of America
- Center for Healthy Aging, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Christopher D. Link
- Institute for Behavioral Genetics & Department of Integrative Physiology, University of Colorado at Boulder, Boulder, Colorado, United States of America
| | - Shane L. Rea
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
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19
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Nafisinia M, Guo Y, Dang X, Li J, Chen Y, Zhang J, Lake NJ, Gold WA, Riley LG, Thorburn DR, Keating B, Xu X, Hakonarson H, Christodoulou J. Whole Exome Sequencing Identifies the Genetic Basis of Late-Onset Leigh Syndrome in a Patient with MRI but Little Biochemical Evidence of a Mitochondrial Disorder. JIMD Rep 2016; 32:117-124. [PMID: 27344648 DOI: 10.1007/8904_2016_541] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 01/25/2016] [Accepted: 01/26/2016] [Indexed: 03/11/2023] Open
Abstract
Leigh syndrome is a subacute necrotising encephalomyopathy proven by post-mortem analysis of brain tissue showing spongiform lesions with vacuolation of the neuropil followed by demyelination, gliosis and capillary proliferation caused by mutations in one of over 75 different genes, including nuclear- and mitochondrial-encoded genes, most of which are associated with mitochondrial respiratory chain function. In this study, we report a patient with suspected Leigh syndrome presenting with seizures, ptosis, scoliosis, dystonia, symmetrical putaminal abnormalities and a lactate peak on brain MRS, but showing normal MRC enzymology in muscle and liver, thereby complicating the diagnosis. Whole exome sequencing uncovered compound heterozygous mutations in NADH dehydrogenase (ubiquinone) flavoprotein 1 gene (NDUFV1), c.1162+4A>C (NM_007103.3), resulting in skipping of exon 8, and c.640G>A, causing the amino acid substitution p.Glu214Lys, both of which have previously been reported in a patient with complex I deficiency. Patient fibroblasts showed a significant reduction in NDUFV1 protein expression, decreased complex CI and complex IV assembly and consequential reductions in the enzymatic activities of both complexes by 38% and 67%, respectively. The pathogenic effect of these variations was further confirmed by immunoblot analysis of subunits for MRC enzyme complexes in patient muscle, liver and fibroblast where we observed 90%, 60% and 95% reduction in complex CI, respectively. Together these studies highlight the importance of a comprehensive, multipronged approach to the laboratory evaluation of patients with suspected Leigh syndrome.
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Affiliation(s)
- Michael Nafisinia
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Locked Bag 4001, Sydney, NSW, 2145, Australia.,Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Yiran Guo
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Xiao Dang
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen, 518083, China.,Shenzen Key Laboratory of Neurogenomics, BGI-Shenzen, Shenzhen, 518083, China
| | - Jiankang Li
- Shenzen Key Laboratory of Neurogenomics, BGI-Shenzen, Shenzhen, 518083, China
| | - Yulan Chen
- Shenzen Key Laboratory of Neurogenomics, BGI-Shenzen, Shenzhen, 518083, China
| | - Jianguo Zhang
- Shenzen Key Laboratory of Neurogenomics, BGI-Shenzen, Shenzhen, 518083, China
| | - Nicole J Lake
- Murdoch Childrens Research Institute and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Wendy A Gold
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Locked Bag 4001, Sydney, NSW, 2145, Australia.,Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Lisa G Riley
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Locked Bag 4001, Sydney, NSW, 2145, Australia.,Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - David R Thorburn
- Murdoch Childrens Research Institute and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Brendan Keating
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Xun Xu
- Shenzen Key Laboratory of Neurogenomics, BGI-Shenzen, Shenzhen, 518083, China
| | - Hakon Hakonarson
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - John Christodoulou
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Locked Bag 4001, Sydney, NSW, 2145, Australia. .,Discipline of Paediatrics and Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia. .,Discipline of Genetic Medicine, Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
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20
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Gaffney CJ, Shephard F, Chu J, Baillie DL, Rose A, Constantin-Teodosiu D, Greenhaff PL, Szewczyk NJ. Degenerin channel activation causes caspase-mediated protein degradation and mitochondrial dysfunction in adult C. elegans muscle. J Cachexia Sarcopenia Muscle 2016; 7:181-92. [PMID: 27493871 PMCID: PMC4864282 DOI: 10.1002/jcsm.12040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 03/17/2015] [Accepted: 04/09/2015] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Declines in skeletal muscle structure and function are found in various clinical populations, but the intramuscular proteolytic pathways that govern declines in these individuals remain relatively poorly understood. The nematode Caenorhabditis elegans has been developed into a model for identifying and understanding these pathways. Recently, it was reported that UNC-105/degenerin channel activation produced muscle protein degradation via an unknown mechanism. METHODS Generation of transgenic and double mutant C. elegans, RNAi, and drug treatments were utilized to assess molecular events governing protein degradation. Western blots were used to measure protein content. Cationic dyes and adenosine triphosphate (ATP) production assays were utilized to measure mitochondrial function. RESULTS unc-105 gain-of-function mutants display aberrant muscle protein degradation and a movement defect; both are reduced in intragenic revertants and in let-2 mutants that gate the hyperactive UNC-105 channel. Degradation is not suppressed by interventions suppressing proteasome-mediated, autophagy-mediated, or calpain-mediated degradation nor by suppressors of degenerin-induced neurodegeneration. Protein degradation, but not the movement defect, is decreased by treatment with caspase inhibitors or RNAi against ced-3 or ced-4. Adult unc-105 muscles display a time-dependent fragmentation of the mitochondrial reticulum that is associated with impaired mitochondrial membrane potential and that correlates with decreased rates of maximal ATP production. Reduced levels of CED-4, which is sufficient to activate CED-3 in vitro, are observed in unc-105 mitochondrial isolations. CONCLUSIONS Constitutive cationic influx into muscle appears to cause caspase degradation of cytosolic proteins as the result of mitochondrial dysfunction, which may be relevant to ageing and sarcopenia.
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Affiliation(s)
- Christopher J Gaffney
- MRC/ARUK Centre for Musculoskeletal Ageing Research, Faculty of Medicine and Health Sciences University of Nottingham Nottingham NG7 2UH UK
| | - Freya Shephard
- MRC/ARUK Centre for Musculoskeletal Ageing Research, Faculty of Medicine and Health Sciences University of Nottingham Nottingham NG7 2UH UK
| | - Jeff Chu
- Department of Molecular Biology and Biochemistry Simon Fraser University Burnaby BCV5A 1S6 Canada; Department of Medical Genetics University of British Columbia Vancouver BCV6T 1Z4 Canada
| | - David L Baillie
- Department of Molecular Biology and Biochemistry Simon Fraser University Burnaby BC V5A 1S6 Canada
| | - Ann Rose
- Department of Medical Genetics University of British Columbia Vancouver BC V6T 1Z4 Canada
| | - Dumitru Constantin-Teodosiu
- MRC/ARUK Centre for Musculoskeletal Ageing Research, Faculty of Medicine and Health Sciences University of Nottingham Nottingham NG7 2UH UK
| | - Paul L Greenhaff
- MRC/ARUK Centre for Musculoskeletal Ageing Research, Faculty of Medicine and Health Sciences University of Nottingham Nottingham NG7 2UH UK
| | - Nathaniel J Szewczyk
- MRC/ARUK Centre for Musculoskeletal Ageing Research, Faculty of Medicine and Health Sciences University of Nottingham Nottingham NG7 2UH UK
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Mishur RJ, Khan M, Munkácsy E, Sharma L, Bokov A, Beam H, Radetskaya O, Borror M, Lane R, Bai Y, Rea SL. Mitochondrial metabolites extend lifespan. Aging Cell 2016; 15:336-48. [PMID: 26729005 PMCID: PMC4783347 DOI: 10.1111/acel.12439] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2015] [Indexed: 12/26/2022] Open
Abstract
Disruption of mitochondrial respiration in the nematode Caenorhabditis elegans can extend lifespan. We previously showed that long-lived respiratory mutants generate elevated amounts of α-ketoacids. These compounds are structurally related to α-ketoglutarate, suggesting they may be biologically relevant. Here, we show that provision of several such metabolites to wild-type worms is sufficient to extend their life. At least one mode of action is through stabilization of hypoxia-inducible factor-1 (HIF-1). We also find that an α-ketoglutarate mimetic, 2,4-pyridinedicarboxylic acid (2,4-PDA), is alone sufficient to increase the lifespan of wild-type worms and this effect is blocked by removal of HIF-1. HIF-1 is constitutively active in isp-1(qm150) Mit mutants, and accordingly, 2,4-PDA does not further increase their lifespan. Incubation of mouse 3T3-L1 fibroblasts with life-prolonging α-ketoacids also results in HIF-1α stabilization. We propose that metabolites that build up following mitochondrial respiratory dysfunction form a novel mode of cell signaling that acts to regulate lifespan.
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Affiliation(s)
- Robert J. Mishur
- The Barshop Institute for Longevity and Aging StudiesUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
- Department of PhysiologyUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
| | - Maruf Khan
- The Barshop Institute for Longevity and Aging StudiesUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
- Department of PhysiologyUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
| | - Erin Munkácsy
- The Barshop Institute for Longevity and Aging StudiesUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
- Department of Cellular & Structural BiologyUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
| | - Lokendra Sharma
- Department of Cellular & Structural BiologyUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
- Biotechnology ProgrammeCenter for Biological SciencesCentral University of South BiharPatna800014India
| | - Alex Bokov
- Department of Epidemiology and BiostatisticsUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
| | - Haley Beam
- The Barshop Institute for Longevity and Aging StudiesUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
| | - Oxana Radetskaya
- The Barshop Institute for Longevity and Aging StudiesUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
| | - Megan Borror
- The Barshop Institute for Longevity and Aging StudiesUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
| | - Rebecca Lane
- The Barshop Institute for Longevity and Aging StudiesUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
| | - Yidong Bai
- Department of Cellular & Structural BiologyUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
| | - Shane L. Rea
- The Barshop Institute for Longevity and Aging StudiesUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
- Department of PhysiologyUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
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Nuclear-encoded cytochrome c oxidase subunit 4 regulates BMI1 expression and determines proliferative capacity of high-grade gliomas. Oncotarget 2015; 6:4330-44. [PMID: 25726526 PMCID: PMC4414193 DOI: 10.18632/oncotarget.3015] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 12/31/2014] [Indexed: 12/20/2022] Open
Abstract
Nuclear-encoded cytochrome c oxidase subunit 4 (COX4) is a key regulatory subunit of mammalian cytochrome c oxidase, and recent studies have demonstrated that COX4 isoform 1 (COX4-1) could have a role in glioma chemoresistance. The Polycomb complex protein BMI1 is a stem cell regulatory gene implicated in the pathogenesis of many aggressive cancers, including glioma. This study sought to determine if COX4 regulates BMI1 and modulates tumor cell proliferation. Using The Cancer Genome Atlas database and a retrospective data set from patients with glioblastoma multiforme, we found that BMI1 expression levels positively correlated with COX4-1 expression and overall survival. Whereas COX4-1 promoted cell growth by increasing BMI1 expression, COX4-2 inhibited cell growth even in cells overexpressing BMI1. We also demonstrate that COX4-1 attenuates mitochondrial reactive oxygen species (ROS) production, which is required for COX4-1-mediated effects on BMI1 expression and cell proliferation. Notably, mice bearing COX4-1-expressing glioma cell xenografts quickly developed invasive tumors characterized by the presence of multiple lesions positive for Ki-67, BMI1, and COX4-1, whereas mice bearing COX4-2-expressing xenografts rarely developed tumors by this point. COX4-1 also promoted the self-renewal of glioma stem-like cells, consistent with the reported role of BMI1 in stem cell growth. Taken together, these findings identify a novel COX4-1-mitochondrial ROS axis, in which differential expression of COX4 isoforms regulates mitochondrial ROS production and controls BMI1 expression.
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Tether mutations that restore function and suppress pleiotropic phenotypes of the C. elegans isp-1(qm150) Rieske iron-sulfur protein. Proc Natl Acad Sci U S A 2015; 112:E6148-57. [PMID: 26504246 DOI: 10.1073/pnas.1509416112] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mitochondria play an important role in numerous diseases as well as normative aging. Severe reduction in mitochondrial function contributes to childhood disorders such as Leigh Syndrome, whereas mild disruption can extend the lifespan of model organisms. The Caenorhabditis elegans isp-1 gene encodes the Rieske iron-sulfur protein subunit of cytochrome c oxidoreductase (complex III of the electron transport chain). The partial loss of function allele, isp-1(qm150), leads to several pleiotropic phenotypes. To better understand the molecular mechanisms of ISP-1 function, we sought to identify genetic suppressors of the delayed development of isp-1(qm150) animals. Here we report a series of intragenic suppressors, all located within a highly conserved six amino acid tether region of ISP-1. These intragenic mutations suppress all of the evaluated isp-1(qm150) phenotypes, including developmental rate, pharyngeal pumping rate, brood size, body movement, activation of the mitochondrial unfolded protein response reporter, CO2 production, mitochondrial oxidative phosphorylation, and lifespan extension. Furthermore, analogous mutations show a similar effect when engineered into the budding yeast Rieske iron-sulfur protein Rip1, revealing remarkable conservation of the structure-function relationship of these residues across highly divergent species. The focus on a single subunit as causal both in generation and in suppression of diverse pleiotropic phenotypes points to a common underlying molecular mechanism, for which we propose a "spring-loaded" model. These observations provide insights into how gating and control processes influence the function of ISP-1 in mediating pleiotropic phenotypes including developmental rate, movement, sensitivity to stress, and longevity.
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Metalloprotease OMA1 Fine-tunes Mitochondrial Bioenergetic Function and Respiratory Supercomplex Stability. Sci Rep 2015; 5:13989. [PMID: 26365306 PMCID: PMC4568518 DOI: 10.1038/srep13989] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 08/13/2015] [Indexed: 12/11/2022] Open
Abstract
Mitochondria are involved in key cellular functions including energy production, metabolic homeostasis, and apoptosis. Normal mitochondrial function is preserved by several interrelated mechanisms. One mechanism - intramitochondrial quality control (IMQC) - is represented by conserved proteases distributed across mitochondrial compartments. Many aspects and physiological roles of IMQC components remain unclear. Here, we show that the IMQC protease Oma1 is required for the stability of the respiratory supercomplexes and thus balanced and tunable bioenergetic function. Loss of Oma1 activity leads to a specific destabilization of respiratory supercomplexes and consequently to unbalanced respiration and progressive respiratory decline in yeast. Similarly, experiments in cultured Oma1-deficient mouse embryonic fibroblasts link together impeded supercomplex stability and inability to maintain proper respiration under conditions that require maximal bioenergetic output. Finally, transient knockdown of OMA1 in zebrafish leads to impeded bioenergetics and morphological defects of the heart and eyes. Together, our biochemical and genetic studies in yeast, zebrafish and mammalian cells identify a novel and conserved physiological role for Oma1 protease in fine-tuning of respiratory function. We suggest that this unexpected physiological role is important for cellular bioenergetic plasticity and may contribute to Oma1-associated disease phenotypes in humans.
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25
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Decaffeinated green tea extract rich in epigallocatechin-3-gallate prevents fatty liver disease by increased activities of mitochondrial respiratory chain complexes in diet-induced obesity mice. J Nutr Biochem 2015; 26:1348-56. [PMID: 26300331 DOI: 10.1016/j.jnutbio.2015.07.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 06/30/2015] [Accepted: 07/06/2015] [Indexed: 12/24/2022]
Abstract
Nonalcoholic fatty liver disease has been considered the hepatic manifestation of obesity. It is unclear whether supplementation with green tea extract rich in epigallocatechin-3-gallate (EGCG) influences the activity of mitochondrial respiratory chain complexes and insulin resistance in the liver. EGCG regulated hepatic mitochondrial respiratory chain complexes and was capable of improving lipid metabolism, attenuating insulin resistance in obese mice. Mice were divided into four groups: control diet+water (CW) or EGCG (CE) and hyperlipidic diet+water (HFW) or EGCG (HFE). All animals received water and diets ad libitum for 16 weeks. Placebo groups received water (0.1 ml/day) and EGCG groups (0.1 ml EGCG and 50 mg/kg/day) by gavage. Cytokines concentrations were obtained by ELISA, protein expression through Western blotting and mitochondrial complex enzymatic activity by colorimetric assay of substrate degradation. HFW increased body weight gain, adiposity index, retroperitoneal and mesenteric adipose tissue relative weight, serum glucose, insulin and Homeostasis Model Assessment of Basal Insulin Resistance (HOMA-IR); glucose intolerance was observed in oral glucose tolerance test (OGTT) as well as ectopic fat liver deposition. HFE group decreased body weight gain, retroperitoneal and mesenteric adipose tissue relative weight, HOMA-IR, insulin levels and liver fat accumulation; increased complexes II-III and IV and malate dehydrogenase activities and improvement in glucose uptake in OGTT and insulin sensitivity by increased protein expression of total AKT, IRα and IRS1. We did not find alterations in inflammatory parameters analyzed. EGCG was able to prevent obesity stimulating the mitochondrial complex chain, increasing energy expenditure, particularly from the oxidation of lipid substrates, thereby contributing to the prevention of hepatic steatosis and improved insulin sensitivity.
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26
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Da-Rè C, von Stockum S, Biscontin A, Millino C, Cisotto P, Zordan MA, Zeviani M, Bernardi P, De Pittà C, Costa R. Leigh syndrome in Drosophila melanogaster: morphological and biochemical characterization of Surf1 post-transcriptional silencing. J Biol Chem 2014; 289:29235-46. [PMID: 25164807 PMCID: PMC4200275 DOI: 10.1074/jbc.m114.602938] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 08/26/2014] [Indexed: 01/20/2023] Open
Abstract
Leigh Syndrome (LS) is the most common early-onset, progressive mitochondrial encephalopathy usually leading to early death. The single most prevalent cause of LS is occurrence of mutations in the SURF1 gene, and LS(Surf1) patients show a ubiquitous and specific decrease in the activity of mitochondrial respiratory chain complex IV (cytochrome c oxidase, COX). SURF1 encodes an inner membrane mitochondrial protein involved in COX assembly. We established a Drosophila melanogaster model of LS based on the post-transcriptional silencing of CG9943, the Drosophila homolog of SURF1. Knockdown of Surf1 was induced ubiquitously in larvae and adults, which led to lethality; in the mesodermal derivatives, which led to pupal lethality; or in the central nervous system, which allowed survival. A biochemical characterization was carried out in knockdown individuals, which revealed that larvae unexpectedly displayed defects in all complexes of the mitochondrial respiratory chain and in the F-ATP synthase, while adults had a COX-selective impairment. Silencing of Surf1 expression in Drosophila S2R(+) cells led to selective loss of COX activity associated with decreased oxygen consumption and respiratory reserve. We conclude that Surf1 is essential for COX activity and mitochondrial function in D. melanogaster, thus providing a new tool that may help clarify the pathogenic mechanisms of LS.
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Affiliation(s)
| | | | | | - Caterina Millino
- CRIBI Biotechnology Centre, University of Padova, 35121 Padova, Italy and
| | | | | | - Massimo Zeviani
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
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27
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Enriquez JA, Lenaz G. Coenzyme q and the respiratory chain: coenzyme q pool and mitochondrial supercomplexes. Mol Syndromol 2014; 5:119-40. [PMID: 25126045 DOI: 10.1159/000363364] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Two alternative models of organization of the mitochondrial electron transport chain (mETC) have been alternatively favored or questioned by the accumulation evidences of different sources, the solid model or the random collision model. Both agree in the number of respiratory complexes (I-IV) that participate in the mETC, but while the random collision model proposes that Complexes I-IV do not interact physically and that electrons are transferred between them by coenzyme Q and cytochrome c, the solid model proposes that all complexes super-assemble in the so-called respirasome. Recently, the plasticity model has been developed to incorporate the solid and the random collision model as extreme situations of a dynamic organization, allowing super-assembly free movement of the respiratory complexes. In this review, we evaluate the supporting evidences of each model and the implications of the super-assembly in the physiological role of coenzyme Q.
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Affiliation(s)
| | - Giorgio Lenaz
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Bologna, Italy
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28
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Castelein N, Muschol M, Dhondt I, Cai H, De Vos WH, Dencher NA, Braeckman BP. Mitochondrial efficiency is increased in axenically cultured Caenorhabditis elegans. Exp Gerontol 2014; 56:26-36. [DOI: 10.1016/j.exger.2014.02.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 02/07/2014] [Accepted: 02/11/2014] [Indexed: 11/25/2022]
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29
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Effects of the mitochondrial respiratory chain on longevity in C. elegans. Exp Gerontol 2014; 56:245-55. [DOI: 10.1016/j.exger.2014.03.028] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/27/2014] [Accepted: 03/28/2014] [Indexed: 12/21/2022]
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30
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Munkácsy E, Rea SL. The paradox of mitochondrial dysfunction and extended longevity. Exp Gerontol 2014; 56:221-33. [PMID: 24699406 PMCID: PMC4104296 DOI: 10.1016/j.exger.2014.03.016] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/02/2014] [Accepted: 03/07/2014] [Indexed: 01/01/2023]
Abstract
Mitochondria play numerous, essential roles in the life of eukaryotes. Disruption of mitochondrial function in humans is often pathological or even lethal. Surprisingly, in some organisms mitochondrial dysfunction can result in life extension. This paradox has been studied most extensively in the long-lived Mit mutants of the nematode Caenorhabditis elegans. In this review, we explore the major responses that are activated following mitochondrial dysfunction in these animals and how these responses potentially act to extend their life. We focus our attention on five broad areas of current research--reactive oxygen species signaling, the mitochondrial unfolded protein response, autophagy, metabolic adaptation, and the roles played by various transcription factors. Lastly, we also examine why disruption of complexes I and II differ in their ability to induce the Mit phenotype and extend lifespan.
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Affiliation(s)
- Erin Munkácsy
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78245-3207, USA; Department of Cell and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78245-3207, USA
| | - Shane L Rea
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78245-3207, USA; Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78245-3207, USA.
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31
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Khacho M, Tarabay M, Patten D, Khacho P, MacLaurin JG, Guadagno J, Bergeron R, Cregan SP, Harper ME, Park DS, Slack RS. Acidosis overrides oxygen deprivation to maintain mitochondrial function and cell survival. Nat Commun 2014; 5:3550. [PMID: 24686499 PMCID: PMC3988820 DOI: 10.1038/ncomms4550] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Accepted: 03/05/2014] [Indexed: 02/07/2023] Open
Abstract
Sustained cellular function and viability of high-energy demanding post-mitotic cells rely on the continuous supply of ATP. The utilization of mitochondrial oxidative phosphorylation for efficient ATP generation is a function of oxygen levels. As such, oxygen deprivation, in physiological or pathological settings, has profound effects on cell metabolism and survival. Here we show that mild extracellular acidosis, a physiological consequence of anaerobic metabolism, can reprogramme the mitochondrial metabolic pathway to preserve efficient ATP production regardless of oxygen levels. Acidosis initiates a rapid and reversible homeostatic programme that restructures mitochondria, by regulating mitochondrial dynamics and cristae architecture, to reconfigure mitochondrial efficiency, maintain mitochondrial function and cell survival. Preventing mitochondrial remodelling results in mitochondrial dysfunction, fragmentation and cell death. Our findings challenge the notion that oxygen availability is a key limiting factor in oxidative metabolism and brings forth the concept that mitochondrial morphology can dictate the bioenergetic status of post-mitotic cells. In hypoxic conditions, cells depend on anaerobic respiration, which results in extracellular acidosis. Khacho et al. find that acidosis serves a protective function, enhancing mitochondrial respiratory capacity and sustaining ATP synthesis despite limited oxygen availability, by both promoting mitochondrial fusion and inhibiting fission.
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Affiliation(s)
- Mireille Khacho
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Michelle Tarabay
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - David Patten
- 1] Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada [2]
| | - Pamela Khacho
- 1] Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada [2]
| | - Jason G MacLaurin
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Jennifer Guadagno
- Department of Physiology and Pharmacology, J. Allyn Taylor Centre for Cell Biology, Robarts Research Institute, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Richard Bergeron
- 1] Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada [2] Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8M5, Canada
| | - Sean P Cregan
- Department of Physiology and Pharmacology, J. Allyn Taylor Centre for Cell Biology, Robarts Research Institute, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Mary-Ellen Harper
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - David S Park
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Ruth S Slack
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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Functional role of mitochondrial respiratory supercomplexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:427-43. [DOI: 10.1016/j.bbabio.2013.11.002] [Citation(s) in RCA: 224] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 10/30/2013] [Accepted: 11/02/2013] [Indexed: 12/30/2022]
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Respiratory Chain Supercomplexes in Mitochondria. THE STRUCTURAL BASIS OF BIOLOGICAL ENERGY GENERATION 2014. [DOI: 10.1007/978-94-017-8742-0_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Suthammarak W, Somerlot BH, Opheim E, Sedensky M, Morgan PG. Novel interactions between mitochondrial superoxide dismutases and the electron transport chain. Aging Cell 2013; 12:1132-40. [PMID: 23895727 DOI: 10.1111/acel.12144] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2013] [Indexed: 12/16/2022] Open
Abstract
The processes that control aging remain poorly understood. We have exploited mutants in the nematode, Caenorhabditis elegans, that compromise mitochondrial function and scavenging of reactive oxygen species (ROS) to understand their relation to lifespan. We discovered unanticipated roles and interactions of the mitochondrial superoxide dismutases (mtSODs): SOD-2 and SOD-3. Both SODs localize to mitochondrial supercomplex I:III:IV. Loss of SOD-2 specifically (i) decreases the activities of complexes I and II, complexes III and IV remain normal; (ii) increases the lifespan of animals with a complex I defect, but not the lifespan of animals with a complex II defect, and kills an animal with a complex III defect; (iii) induces a presumed pro-inflammatory response. Knockdown of a molecule that may be a pro-inflammatory mediator very markedly extends lifespan and health of certain mitochondrial mutants. The relationship between the electron transport chain, ROS, and lifespan is complex, and defects in mitochondrial function have specific interactions with ROS scavenging mechanisms. We conclude that mtSODs are embedded within the supercomplex I:III:IV and stabilize or locally protect it from reactive oxygen species (ROS) damage. The results call for a change in the usual paradigm for the interaction of electron transport chain function, ROS release, scavenging, and compensatory responses.
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Affiliation(s)
- Wichit Suthammarak
- Department of Anesthesiology and Pain Medicine; Center for Developmental Therapeutics; University of Washington and Seattle Children's Research Institute; Seattle WA USA
| | | | - Elyce Opheim
- Department of Anesthesiology and Pain Medicine; Center for Developmental Therapeutics; University of Washington and Seattle Children's Research Institute; Seattle WA USA
| | - Margaret Sedensky
- Department of Anesthesiology and Pain Medicine; Center for Developmental Therapeutics; University of Washington and Seattle Children's Research Institute; Seattle WA USA
- Department of Genetics; Case Western Reserve University; Cleveland OH USA
| | - Philip G. Morgan
- Department of Anesthesiology and Pain Medicine; Center for Developmental Therapeutics; University of Washington and Seattle Children's Research Institute; Seattle WA USA
- Department of Genetics; Case Western Reserve University; Cleveland OH USA
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35
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Buck KJ, Walter NAR, Denmark DL. Genetic variability of respiratory complex abundance, organization and activity in mouse brain. GENES BRAIN AND BEHAVIOR 2013; 13:135-43. [PMID: 24164700 DOI: 10.1111/gbb.12101] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/22/2013] [Accepted: 10/24/2013] [Indexed: 12/14/2022]
Abstract
Mitochondrial dysfunction is implicated in the etiology and pathogenesis of numerous human disorders involving tissues with high energy demand. Murine models are widely used to elucidate genetic determinants of phenotypes relevant to human disease, with recent studies of C57BL/6J (B6), DBA/2J (D2) and B6xD2 populations implicating naturally occurring genetic variation in mitochondrial function/dysfunction. Using blue native polyacrylamide gel electrophoresis, immunoblots and in-gel activity analyses of complexes I, II, III, IV and V, our studies are the first to assess abundance, organization and catalytic activity of mitochondrial respiratory complexes and supercomplexes in mouse brain. Remarkable strain differences in supercomplex assembly and associated activity are evident, without differences in individual complexes I, II, III or IV. Supercomplexes I1 III2 IV2-3 exhibit robust complex III immunoreactivity and activities of complexes I and IV in D2, but with little detected in B6 for I1 III2 IV2 , and I1 III2 IV3 is not detected in B6. I1 III2 IV1 and I1 III2 are abundant and catalytically active in both strains, but significantly more so in B6. Furthermore, while supercomplex III2 IV1 is abundant in D2, none is detected in B6. In aggregate, these results indicate a shift toward more highly assembled supercomplexes in D2. Respiratory supercomplexes are thought to increase electron flow efficiency and individual complex stability, and to reduce electron leak and generation of reactive oxygen species. Our results provide a framework to begin assessing the role of respiratory complex suprastructure in genetic vulnerability and treatment for a wide variety of mitochondrial-related disorders.
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Affiliation(s)
- K J Buck
- Department of Behavioral Neuroscience, Veterans Affairs Medical Center and Oregon Health & Science University, Portland, OR, USA
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Butler JA, Mishur RJ, Bhaskaran S, Rea SL. A metabolic signature for long life in the Caenorhabditis elegans Mit mutants. Aging Cell 2013; 12:130-8. [PMID: 23173729 DOI: 10.1111/acel.12029] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2012] [Indexed: 11/26/2022] Open
Abstract
Mit mutations that disrupt function of the mitochondrial electron transport chain can, inexplicably, prolong Caenorhabditis elegans lifespan. In this study we use a metabolomics approach to identify an ensemble of mitochondrial-derived α-ketoacids and α-hydroxyacids that are produced by long-lived Mit mutants but not by other long-lived mutants or by short-lived mitochondrial mutants. We show that accumulation of these compounds is dependent on concerted inhibition of three α-ketoacid dehydrogenases that share dihydrolipoamide dehydrogenase (DLD) as a common subunit, a protein previously linked in humans with increased risk of Alzheimer's disease. When the expression of DLD in wild-type animals was reduced using RNA interference we observed an unprecedented effect on lifespan - as RNAi dosage was increased lifespan was significantly shortened, but, at higher doses, it was significantly lengthened, suggesting that DLD plays a unique role in modulating length of life. Our findings provide novel insight into the origin of the Mit phenotype.
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Affiliation(s)
- Jeffrey A. Butler
- Barshop Institute for Longevity and Aging Studies and the Department of Physiology; University of Texas Health Science Center; San Antonio; TX; 78240; USA
| | - Robert J. Mishur
- Barshop Institute for Longevity and Aging Studies and the Department of Physiology; University of Texas Health Science Center; San Antonio; TX; 78240; USA
| | - Shylesh Bhaskaran
- Barshop Institute for Longevity and Aging Studies and the Department of Physiology; University of Texas Health Science Center; San Antonio; TX; 78240; USA
| | - Shane L. Rea
- Barshop Institute for Longevity and Aging Studies and the Department of Physiology; University of Texas Health Science Center; San Antonio; TX; 78240; USA
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Quintana A, Morgan PG, Kruse SE, Palmiter RD, Sedensky MM. Altered anesthetic sensitivity of mice lacking Ndufs4, a subunit of mitochondrial complex I. PLoS One 2012; 7:e42904. [PMID: 22912761 PMCID: PMC3422219 DOI: 10.1371/journal.pone.0042904] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 07/12/2012] [Indexed: 02/07/2023] Open
Abstract
Anesthetics are in routine use, yet the mechanisms underlying their function are incompletely understood. Studies in vitro demonstrate that both GABA(A) and NMDA receptors are modulated by anesthetics, but whole animal models have not supported the role of these receptors as sole effectors of general anesthesia. Findings in C. elegans and in children reveal that defects in mitochondrial complex I can cause hypersensitivity to volatile anesthetics. Here, we tested a knockout (KO) mouse with reduced complex I function due to inactivation of the Ndufs4 gene, which encodes one of the subunits of complex I. We tested these KO mice with two volatile and two non-volatile anesthetics. KO and wild-type (WT) mice were anesthetized with isoflurane, halothane, propofol or ketamine at post-natal (PN) days 23 to 27, and tested for loss of response to tail clamp (isoflurane and halothane) or loss of righting reflex (propofol and ketamine). KO mice were 2.5 - to 3-fold more sensitive to isoflurane and halothane than WT mice. KO mice were 2-fold more sensitive to propofol but resistant to ketamine. These changes in anesthetic sensitivity are the largest recorded in a mammal.
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Affiliation(s)
- Albert Quintana
- Howard Hughes Medical Institute and Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Philip G. Morgan
- Department of Anesthesiology and Pain Medicine, University of Washington and Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, Washington, United States of America
- * E-mail:
| | - Shane E. Kruse
- Howard Hughes Medical Institute and Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Richard D. Palmiter
- Howard Hughes Medical Institute and Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Margaret M. Sedensky
- Department of Anesthesiology and Pain Medicine, University of Washington and Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, Washington, United States of America
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Quality improvement of mitochondrial respiratory chain complex enzyme assays using Caenorhabditis elegans. Genet Med 2012; 13:794-9. [PMID: 21633293 DOI: 10.1097/gim.0b013e31821afca5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE The diagnosis of a mitochondrial disorder relies heavily on the enzymatic analysis of mitochondrial respiratory chain complexes in muscle or other tissues. However, considerable differences exist between clinical laboratories in the protocols or particular tests used for evaluation. In addition, laboratories can encounter difficulties in consistent technique, as well as procurement of adequate positive or negative controls. Currently, there is no external quality assurance for respiratory chain complex assays. In this study, we explored the use of Caenorhabditis elegans mitochondria as a potential aid to diagnostic centers that perform respiratory chain complex assays. METHOD Five diagnostic test centers in the United States and one from Australia comparatively analyzed enzyme activities of mitochondria from C. elegans. The first survey consisted of three open-labeled samples including one normal control and two mutants; the second survey consisted of one open-labeled normal control and two blinded samples. RESULTS There was very good concordance among laboratories in detecting the majority of the defects present in the mutant specimens. Despite the ability to detect respiratory chain complex defects, the scatter between centers for certain enzymatic assays, particularly I + III, II, III, and IV, led to different diagnostic interpretations between the centers. CONCLUSION The data strongly support the need for comparative testing of mitochondrial enzyme assays between multiple laboratories. Our overall results are encouraging for the use of nematode mitochondria as a tool that might provide a virtually inexhaustible supply of mitochondria with defined defects for development of assays and as a potential source of control specimens.
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Chen YC, Taylor EB, Dephoure N, Heo JM, Tonhato A, Papandreou I, Nath N, Denko NC, Gygi SP, Rutter J. Identification of a protein mediating respiratory supercomplex stability. Cell Metab 2012; 15:348-60. [PMID: 22405070 PMCID: PMC3302151 DOI: 10.1016/j.cmet.2012.02.006] [Citation(s) in RCA: 175] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 12/27/2011] [Accepted: 02/08/2012] [Indexed: 11/18/2022]
Abstract
The complexes of the electron transport chain associate into large macromolecular assemblies, which are believed to facilitate efficient electron flow. We have identified a conserved mitochondrial protein, named respiratory supercomplex factor 1 (Rcf1-Yml030w), that is required for the normal assembly of respiratory supercomplexes. We demonstrate that Rcf1 stably and independently associates with both Complex III and Complex IV of the electron transport chain. Deletion of the RCF1 gene caused impaired respiration, probably as a result of destabilization of respiratory supercomplexes. Consistent with the hypothetical function of these respiratory assemblies, loss of RCF1 caused elevated mitochondrial oxidative stress and damage. Finally, we show that knockdown of HIG2A, a mammalian homolog of RCF1, causes impaired supercomplex formation. We suggest that Rcf1 is a member of an evolutionarily conserved protein family that acts to promote respiratory supercomplex assembly and activity.
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Affiliation(s)
- Yu-Chan Chen
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
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Xun Z, Lee DY, Lim J, Canaria CA, Barnebey A, Yanonne SM, McMurray CT. Retinoic acid-induced differentiation increases the rate of oxygen consumption and enhances the spare respiratory capacity of mitochondria in SH-SY5Y cells. Mech Ageing Dev 2012; 133:176-85. [PMID: 22336883 DOI: 10.1016/j.mad.2012.01.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 12/22/2011] [Accepted: 01/29/2012] [Indexed: 01/15/2023]
Abstract
Retinoic acid (RA) is used in differentiation therapy to treat a variety of cancers including neuroblastoma. The contributing factors for its therapeutic efficacy are poorly understood. However, mitochondria (MT) have been implicated as key effectors in RA-mediated differentiation process. Here we utilize the SH-SY5Y human neuroblastoma cell line as a model to examine how RA influences MT during the differentiation process. We find that RA confers an approximately sixfold increase in the oxygen consumption rate while the rate of glycolysis modestly increases. RA treatment does not increase the number of MT or cause measurable changes in the composition of the electron transport chain. Rather, RA treatment significantly increases the mitochondrial spare respiratory capacity. We propose a competition model for the therapeutic effects of RA. Specifically, the high metabolic rate in differentiated cells limits the availability of metabolic nutrients for use by the undifferentiated cells and suppresses their growth. Thus, RA treatment provides a selective advantage for the differentiated state.
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Affiliation(s)
- Zhiyin Xun
- Lawrence Berkeley National Laboratory, Life Sciences Division, 1 Cyclotron Rd., Berkeley, CA 94720, USA
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Lenaz G, Genova ML. Supramolecular Organisation of the Mitochondrial Respiratory Chain: A New Challenge for the Mechanism and Control of Oxidative Phosphorylation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:107-44. [DOI: 10.1007/978-1-4614-3573-0_5] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Hench J, Bratić Hench I, Pujol C, Ipsen S, Brodesser S, Mourier A, Tolnay M, Frank S, Trifunović A. A tissue-specific approach to the analysis of metabolic changes in Caenorhabditis elegans. PLoS One 2011; 6:e28417. [PMID: 22162770 PMCID: PMC3230600 DOI: 10.1371/journal.pone.0028417] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Accepted: 11/08/2011] [Indexed: 01/11/2023] Open
Abstract
The majority of metabolic principles are evolutionarily conserved from nematodes to humans. Caenorhabditis elegans has widely accelerated the discovery of new genes important to maintain organismic metabolic homeostasis. Various methods exist to assess the metabolic state in worms, yet they often require large animal numbers and tend to be performed as bulk analyses of whole worm homogenates, thereby largely precluding a detailed studies of metabolic changes in specific worm tissues. Here, we have adapted well-established histochemical methods for the use on C. elegans fresh frozen sections and demonstrate their validity for analyses of morphological and metabolic changes on tissue level in wild type and various mutant strains. We show how the worm presents on hematoxylin and eosin (H&E) stained sections and demonstrate their usefulness in monitoring and the identification of morphological abnormalities. In addition, we demonstrate how Oil-Red-O staining on frozen worm cross-sections permits quantification of lipid storage, avoiding the artifact-prone fixation and permeabilization procedures of traditional whole-mount protocols. We also adjusted standard enzymatic stains for respiratory chain subunits (NADH, SDH, and COX) to monitor metabolic states of various C. elegans tissues. In summary, the protocols presented here provide technical guidance to obtain robust, reproducible and quantifiable tissue-specific data on worm morphology as well as carbohydrate, lipid and mitochondrial energy metabolism that cannot be obtained through traditional biochemical bulk analyses of worm homogenates. Furthermore, analysis of worm cross-sections overcomes the common problem with quantification in three-dimensional whole-mount specimens.
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Affiliation(s)
- Jürgen Hench
- Department of Neuropathology, Institute of Pathology, University Hospital Basel, Basel, Switzerland.
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Yang YY, Vasta V, Hahn S, Gangoiti JA, Opheim E, Sedensky MM, Morgan PG. The role of DMQ(9) in the long-lived mutant clk-1. Mech Ageing Dev 2011; 132:331-9. [PMID: 21745495 DOI: 10.1016/j.mad.2011.06.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 06/03/2011] [Accepted: 06/23/2011] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Ubiquinone (UQ) is a redox active lipid that transfers electrons from complex I or II to complex III in the electron transport chain (ETC). The long-lived Caenorhabditis elegans mutant clk-1 is unable to synthesize its native ubiquinone, and accumulates high amounts of its precursor, 5-demethoxyubiquinone-9 (DMQ(9)). In clk-1, complexes I-III activity is inhibited while complexes II-III activity is normal. We asked whether the complexes I-III defect in clk-1 was caused by: (1) a defect in the ETC; (2) an inhibitory effect of DMQ(9); or (3) a decreased amount of ubiquinone. METHODS We extracted the endogenous quinones from wildtype (N2) and clk-1 mitochondria, replenished them with exogenous ubiquinones, and measured ETC activities. RESULTS Replenishment of extracted mutant and wildtype mitochondria resulted in equal enzymatic activities for complexes I-III and II-III ETC assays. Blue native gels showed that supercomplex formation was indistinguishable between clk-1 and N2. The addition of a pentane extract from clk-1 mitochondria containing DMQ(9) to wildtype mitochondria specifically inhibited complexes I-III activity. UQ in clk-1 mitochondria was oxidized compared to N2. DISCUSSION Our results show that no measurable intrinsic ETC defect exists in clk-1 mitochondria. The data indicate that DMQ(9) specifically inhibits electron transfer from complex I to ubiquinone.
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Affiliation(s)
- Yu-Ying Yang
- Department of Genetics, Case Western Reserve University, Cleveland, OH, United States.
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Kayser EB, Suthammarak W, Morgan PG, Sedensky MM. Isoflurane selectively inhibits distal mitochondrial complex I in Caenorhabditis elegans. Anesth Analg 2011; 112:1321-9. [PMID: 21467554 DOI: 10.1213/ane.0b013e3182121d37] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Complex I of the electron transport chain (ETC) is a possible target of volatile anesthetics (VAs). Complex I enzymatic activities are inhibited by VAs, and dysfunction of complex I can lead to hypersensitivity to VAs in worms and in people. Mutant analysis in Caenorhabditis (C.) elegans suggests that VAs may specifically interfere with complex I function at the binding site for its substrate ubiquinone. We hypothesized that isoflurane inhibits electron transport by competing with ubiquinone for binding to complex I. METHODS Wildtype and mutant C. elegans were used to study the effects of isoflurane on isolated mitochondria. Enzymatic activities of the ETC were assayed and dose-response curves determined using established techniques. Two-dimensional native gels of mitochondrial proteins were performed after exposure of mitochondria to isoflurane. RESULTS Complex I is the most sensitive component of the ETC to isoflurane inhibition; however, the proximal portion of complex I (the flavoprotein) is relatively insensitive to isoflurane. Isoflurane and quinone do not compete for a common binding site on complex I. The absolute rate of complex I enzymatic activity in vitro does not predict immobilization of the animal by isoflurane. Isoflurane had no measurable effect on stability of mitochondrial supercomplexes. Reduction of ubiquinone by complex I displayed positive cooperative kinetics not disrupted by isoflurane. CONCLUSIONS Isoflurane directly inhibits complex I at a site distal to the flavoprotein subcomplex. However, we have excluded our original hypothesis that isoflurane and ubiquinone compete for a common hydrophobic binding site on complex I. In addition, immobilization of the nematode by isoflurane is not due to limiting absolute amounts of complex I electron transport as measured in isolated mitochondria.
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Affiliation(s)
- Ernst-Bernhard Kayser
- Department of Anesthesiology, University of Washington and Center for Developmental Therapeutics, Seattle Children's Research Institute, Seattle, WA 98101-1304, USA.
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