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MacColl Garfinkel A, Mnatsakanyan N, Patel JH, Wills AE, Shteyman A, Smith PJS, Alavian KN, Jonas EA, Khokha MK. Mitochondrial leak metabolism induces the Spemann-Mangold Organizer via Hif-1α in Xenopus. Dev Cell 2023; 58:2597-2613.e4. [PMID: 37673063 PMCID: PMC10840693 DOI: 10.1016/j.devcel.2023.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 06/30/2023] [Accepted: 08/09/2023] [Indexed: 09/08/2023]
Abstract
An instructive role for metabolism in embryonic patterning is emerging, although a role for mitochondria is poorly defined. We demonstrate that mitochondrial oxidative metabolism establishes the embryonic patterning center, the Spemann-Mangold Organizer, via hypoxia-inducible factor 1α (Hif-1α) in Xenopus. Hypoxia or decoupling ATP production from oxygen consumption expands the Organizer by activating Hif-1α. In addition, oxygen consumption is 20% higher in the Organizer than in the ventral mesoderm, indicating an elevation in mitochondrial respiration. To reconcile increased mitochondrial respiration with activation of Hif-1α, we discovered that the "free" c-subunit ring of the F1Fo ATP synthase creates an inner mitochondrial membrane leak, which decouples ATP production from respiration at the Organizer, driving Hif-1α activation there. Overexpression of either the c-subunit or Hif-1α is sufficient to induce Organizer cell fates even when β-catenin is inhibited. We propose that mitochondrial leak metabolism could be a general mechanism for activating Hif-1α and Wnt signaling.
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Affiliation(s)
- Alexandra MacColl Garfinkel
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale University School of Medicine, New Haven, CT 06510, USA; Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT 06510, USA
| | - Nelli Mnatsakanyan
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Jeet H Patel
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA 98195, USA; Program in Molecular and Cellular Biology, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Andrea E Wills
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA 98195, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Amy Shteyman
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT 06510, USA
| | - Peter J S Smith
- Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | | | - Elizabeth Ann Jonas
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT 06510, USA.
| | - Mustafa K Khokha
- Pediatric Genomics Discovery Program, Department of Pediatrics and Genetics, Yale University School of Medicine, New Haven, CT 06510, USA.
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Somnay YR, Wang A, Griffiths KK, Levy RJ. Altered Brown Adipose Tissue Mitochondrial Function in Newborn Fragile X Syndrome Mice. Mitochondrion 2022; 65:1-10. [DOI: 10.1016/j.mito.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 03/21/2022] [Accepted: 04/27/2022] [Indexed: 10/18/2022]
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Barajas MB, Brunner SD, Wang A, Griffiths KK, Levy RJ. Propofol toxicity in the developing mouse heart mitochondria. Pediatr Res 2022; 92:1341-1349. [PMID: 35173299 PMCID: PMC9378757 DOI: 10.1038/s41390-022-01985-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 12/16/2021] [Accepted: 01/30/2022] [Indexed: 12/02/2022]
Abstract
BACKGROUND Propofol infusion syndrome (PRIS) is a potentially lethal consequence of long-term propofol administration. Children are vulnerable and cardiac involvement is often prominent and associated with mortality. We aimed to determine the mechanism of propofol toxicity in newborn mice, hypothesizing that propofol would induce discrete defects within immature cardiac mitochondria. METHODS Newborn murine cardiac mitochondria were exposed to propofol or intralipid in vitro. Non-exposed mitochondria served as controls. Mitochondrial respiration and membrane potential (ΔΨ) were measured and respiratory chain complex kinetics were determined. RESULTS Propofol and intralipid exerted biological activity in isolated mitochondria. Although intralipid effects were a potential confounder, we found that propofol induced a dose-dependent increase in proton leak and caused a defect in substrate oxidation at coenzyme Q (CoQ). These impairments prevented propofol-exposed cardiomyocyte mitochondria from generating an adequate ΔΨ. The addition of the quinone analog, CoQ0, blocked propofol-induced leak and increased Complex II+III activity. CONCLUSIONS Propofol uncoupled immature cardiomyocyte mitochondria by inducing excessive CoQ-sensitive leak and interfered with electron transport at CoQ. The findings provide new insight into the mechanisms of propofol toxicity in the developing heart and may help explain why children are vulnerable to developing PRIS. IMPACT Propofol uncouples immature cardiomyocyte mitochondria by inducing excessive coenzyme Q (CoQ)-sensitive proton leak. Propofol also interferes with electron transport at the level of CoQ. These defects provide new insight into propofol toxicity in the developing heart.
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Affiliation(s)
- Matthew B. Barajas
- grid.239585.00000 0001 2285 2675Department of Anesthesiology, Columbia University Medical Center, New York, NY USA
| | - Sarah D. Brunner
- grid.239585.00000 0001 2285 2675Department of Pediatrics, Division of Pediatric Critical Care Medicine, Columbia University Medical Center, New York, NY USA
| | - Aili Wang
- grid.239585.00000 0001 2285 2675Department of Anesthesiology, Columbia University Medical Center, New York, NY USA
| | - Keren K. Griffiths
- grid.239585.00000 0001 2285 2675Department of Anesthesiology, Columbia University Medical Center, New York, NY USA
| | - Richard J. Levy
- grid.239585.00000 0001 2285 2675Department of Anesthesiology, Columbia University Medical Center, New York, NY USA
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Mookerjee SA, Gerencser AA, Watson MA, Brand MD. Controlled power: how biology manages succinate-driven energy release. Biochem Soc Trans 2021; 49:2929-2939. [PMID: 34882231 PMCID: PMC8786295 DOI: 10.1042/bst20211032] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/08/2021] [Accepted: 11/22/2021] [Indexed: 12/13/2022]
Abstract
Oxidation of succinate by mitochondria can generate a higher protonmotive force (pmf) than can oxidation of NADH-linked substrates. Fundamentally, this is because of differences in redox potentials and gearing. Biology adds kinetic constraints that tune the oxidation of NADH and succinate to ensure that the resulting mitochondrial pmf is suitable for meeting cellular needs without triggering pathology. Tuning within an optimal range is used, for example, to shift ATP consumption between different consumers. Conditions that overcome these constraints and allow succinate oxidation to drive pmf too high can cause pathological generation of reactive oxygen species. We discuss the thermodynamic properties that allow succinate oxidation to drive pmf higher than NADH oxidation, and discuss the evidence for kinetic tuning of ATP production and for pathologies resulting from substantial succinate oxidation in vivo.
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Affiliation(s)
- Shona A. Mookerjee
- Department of Biological and Pharmaceutical Sciences, Touro University California College of Pharmacy, Vallejo, CA, U.S.A
- Buck Institute for Research on Aging, Novato, CA, U.S.A
| | | | | | - Martin D. Brand
- Department of Biological and Pharmaceutical Sciences, Touro University California College of Pharmacy, Vallejo, CA, U.S.A
- Buck Institute for Research on Aging, Novato, CA, U.S.A
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Sabbir MG, Taylor CG, Zahradka P. CAMKK2 regulates mitochondrial function by controlling succinate dehydrogenase expression, post-translational modification, megacomplex assembly, and activity in a cell-type-specific manner. Cell Commun Signal 2021; 19:98. [PMID: 34563205 PMCID: PMC8466908 DOI: 10.1186/s12964-021-00778-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/14/2021] [Indexed: 01/08/2023] Open
Abstract
Background The calcium (Ca2+)/calmodulin (CAM)-activated kinase kinase 2 (CAMKK2)-signaling regulates several physiological processes, for example, glucose metabolism and energy homeostasis, underlying the pathogenesis of metabolic diseases. CAMKK2 exerts its biological function through several downstream kinases, therefore, it is expected that depending on the cell-type-specific kinome profile, the metabolic effects of CAMKK2 and its underlying mechanism may differ. Identification of the cell-type-specific differences in CAMKK2-mediated glucose metabolism will lead to unravelling the organ/tissue-specific role of CAMKK2 in energy metabolism. Therefore, the objective of this study was to understand the cell-type-specific regulation of glucose metabolism, specifically, respiration under CAMKK2 deleted conditions in transformed human embryonic kidney-derived HEK293 and hepatoma-derived HepG2 cells. Methods Cellular respiration was measured in terms of oxygen consumption rate (OCR). OCR and succinate dehydrogenase (SDH) enzyme activity were measured following the addition of substrates. In addition, transcription and proteomic and analyses of the electron transport system (ETS)-associated proteins, including mitochondrial SDH protein complex (complex-II: CII) subunits, specifically SDH subunit B (SDHB), were performed using standard molecular biology techniques. The metabolic effect of the altered SDHB protein content in the mitochondria was further evaluated by cell-type-specific knockdown or overexpression of SDHB. Results CAMKK2 deletion suppressed cellular respiration in both cell types, shifting metabolic phenotype to aerobic glycolysis causing the Warburg effect. However, isolated mitochondria exhibited a cell-type-specific enhancement or dampening of the respiratory kinetics under CAMKK2 deletion conditions. This was mediated in part by the cell-type-specific effect of CAMKK2 loss-of-function on transcription, translation, post-translational modification (PTM), and megacomplex assembly of nuclear-encoded mitochondrial SDH enzyme complex subunits, specifically SDHB. The cell-type-specific increase or decrease in SDHs protein levels, specifically SDHB, under CAMKK2 deletion condition resulted in an increased or decreased enzymatic activity and CII-mediated respiration. This metabolic phenotype was reversed by cell-type-specific knockdown or overexpression of SDHB in respective CAMKK2 deleted cell types. CAMKK2 loss-of-function also affected the overall assembly of mitochondrial supercomplex involving ETS-associated proteins in a cell-type-specific manner, which correlated with differences in mitochondrial bioenergetics. Conclusion This study provided novel insight into CAMKK2-mediated cell-type-specific differential regulation of mitochondrial function, facilitated by the differential expression, PTMs, and assembly of SDHs into megacomplex structures.![]() Video Abstract
Supplementary Information The online version contains supplementary material available at 10.1186/s12964-021-00778-z.
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Affiliation(s)
- Mohammad Golam Sabbir
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Albrechtsen Research Centre, Room R2034 - 351 Taché Avenue, Winnipeg, MB, R2H 2A6, Canada. .,Alzo Biosciences Inc., San Diego, CA, USA.
| | - Carla G Taylor
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Albrechtsen Research Centre, Room R2034 - 351 Taché Avenue, Winnipeg, MB, R2H 2A6, Canada.,Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.,Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada
| | - Peter Zahradka
- Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Albrechtsen Research Centre, Room R2034 - 351 Taché Avenue, Winnipeg, MB, R2H 2A6, Canada.,Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.,Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada
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The newborn Fmr1 knockout mouse: a novel model of excess ubiquinone and closed mitochondrial permeability transition pore in the developing heart. Pediatr Res 2021; 89:456-463. [PMID: 32674111 PMCID: PMC7855053 DOI: 10.1038/s41390-020-1064-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 06/11/2020] [Accepted: 07/02/2020] [Indexed: 11/18/2022]
Abstract
BACKGROUND Mitochondrial permeability transition pore (mPTP) closure triggers cardiomyocyte differentiation during development while pathological opening causes cell death during myocardial ischemia-reperfusion and heart failure. Ubiquinone modulates the mPTP; however, little is known about its mechanistic role in health and disease. We previously found excessive proton leak in newborn Fmr1 KO mouse forebrain caused by ubiquinone deficiency and increased open mPTP probability. Because of the physiological differences between the heart and brain during maturation, we hypothesized that developing Fmr1 KO cardiomyocyte mitochondria would demonstrate dissimilar features. METHODS Newborn male Fmr1 KO mice and controls were assessed. Respiratory chain enzyme activity, ubiquinone content, proton leak, and oxygen consumption were measured in cardiomyocyte mitochondria. Cardiac function was evaluated via echocardiography. RESULTS In contrast to controls, Fmr1 KO cardiomyocyte mitochondria demonstrated increased ubiquinone content and decreased proton leak. Leak was cyclosporine (CsA)-sensitive in controls and CsA-insensitive in Fmr1 KOs. There was no difference in absolute mitochondrial respiration or cardiac function between strains. CONCLUSION These findings establish the newborn Fmr1 KO mouse as a novel model of excess ubiquinone and closed mPTP in the developing heart. Such a model may help provide insight into the biology of cardiac development and pathophysiology of neonatal heart failure. IMPACT Ubiquinone is in excess and the mPTP is closed in the developing FXS heart. Strengthens evidence of open mPTP probability in the normally developing postnatal murine heart and provides new evidence for premature closure of the mPTP in Fmr1 mutants. Establishes a novel model of excess CoQ and a closed pore in the developing heart. Such a model will be a valuable tool used to better understand the role of ubiquinone and the mPTP in the neonatal heart in health and disease.
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Gangloff EJ, Schwartz TS, Klabacka R, Huebschman N, Liu AY, Bronikowski AM. Mitochondria as central characters in a complex narrative: Linking genomics, energetics, pace-of-life, and aging in natural populations of garter snakes. Exp Gerontol 2020; 137:110967. [DOI: 10.1016/j.exger.2020.110967] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 04/11/2020] [Accepted: 05/01/2020] [Indexed: 12/18/2022]
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8
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Griffiths KK, Wang A, Wang L, Tracey M, Kleiner G, Quinzii CM, Sun L, Yang G, Perez-Zoghbi JF, Licznerski P, Yang M, Jonas EA, Levy RJ. Inefficient thermogenic mitochondrial respiration due to futile proton leak in a mouse model of fragile X syndrome. FASEB J 2020; 34:7404-7426. [PMID: 32307754 DOI: 10.1096/fj.202000283rr] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 12/20/2022]
Abstract
Fragile X syndrome (FXS) is the leading known inherited intellectual disability and the most common genetic cause of autism. The full mutation results in transcriptional silencing of the Fmr1 gene and loss of fragile X mental retardation protein (FMRP) expression. Defects in neuroenergetic capacity are known to cause a variety of neurodevelopmental disorders. Thus, we explored the integrity of forebrain mitochondria in Fmr1 knockout mice during the peak of synaptogenesis. We found inefficient thermogenic respiration due to futile proton leak in Fmr1 KO mitochondria caused by coenzyme Q (CoQ) deficiency and an open cyclosporine-sensitive channel. Repletion of mitochondrial CoQ within the Fmr1 KO forebrain closed the channel, blocked the pathological proton leak, restored rates of protein synthesis during synaptogenesis, and normalized the key phenotypic features later in life. The findings demonstrate that FMRP deficiency results in inefficient oxidative phosphorylation during the neurodevelopment and suggest that dysfunctional mitochondria may contribute to the FXS phenotype.
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Affiliation(s)
- Keren K Griffiths
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Aili Wang
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Lifei Wang
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Matthew Tracey
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Giulio Kleiner
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Catarina M Quinzii
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Linlin Sun
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Guang Yang
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Jose F Perez-Zoghbi
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Pawel Licznerski
- Section of Endocrinology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Mu Yang
- Institute of Genomic Medicine and Psychiatry, Columbia University Medical Center, New York, NY, USA
| | - Elizabeth A Jonas
- Section of Endocrinology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Richard J Levy
- Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
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9
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Chinnery PF, Gomez-Duran A. Oldies but Goldies mtDNA Population Variants and Neurodegenerative Diseases. Front Neurosci 2018; 12:682. [PMID: 30369864 PMCID: PMC6194173 DOI: 10.3389/fnins.2018.00682] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 09/10/2018] [Indexed: 12/31/2022] Open
Abstract
mtDNA is transmitted through the maternal line and its sequence variability, which is population specific, is assumed to be phenotypically neutral. However, several studies have shown associations between the variants defining some genetic backgrounds and the susceptibility to several pathogenic phenotypes, including neurodegenerative diseases. Many of these studies have found that some of these variants impact many of these phenotypes, including the ones defining the Caucasian haplogroups H, J, and Uk, while others, such as the ones defining the T haplogroup, have phenotype specific associations. In this review, we will focus on those that have shown a pleiotropic effect in population studies in neurological diseases. We will also explore their bioenergetic and genomic characteristics in order to provide an insight into the role of these variants in disease. Given the importance of mitochondrial population variants in neurodegenerative diseases a deeper analysis of their effects might unravel new mechanisms of disease and help design new strategies for successful treatments.
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Affiliation(s)
- Patrick F Chinnery
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom.,Medical Research Council-Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Aurora Gomez-Duran
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom.,Medical Research Council-Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, United Kingdom
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Duhn PH, Sode J, Hagen CM, Christiansen M, Locht H. Mitochondrial haplogroups in patients with rheumatoid arthritis: No association with disease and disease manifestations. PLoS One 2017; 12:e0188492. [PMID: 29261674 PMCID: PMC5737896 DOI: 10.1371/journal.pone.0188492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 10/09/2017] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVE To describe the distribution of specific mitochondrial DNA (mtDNA) haplogroups (hgs) in a cohort of patients with rheumatoid arthritis (RA). METHODS Two-hundred nineteen consecutive patients with RA had mtDNA isolated from their blood, sequenced and haplotyped. Patients were diagnosed according to the American College of Rheumatology (ACR)/European league against Rheumatism (EULAR) criteria. Demographic and clinical data were retrieved from the Danish nationwide database (DANBIO). Logistic regression analyses were performed to test for associations. RESULTS One-hundred eighty-four patients were eligible for analysis. Haplogroup frequencies were: H (n = 88; 47.8%), U (n = 37; 20.1%), T (n = 22; 12.0%), J (n = 16; 8.7%), K (n = 11; 5.9%), HV (n = 6; 3.3%) and V (n = 4; 2.2%). The distribution of individual hgs was identical to the background population. Radiographic erosions were significantly associated with hg clusters JT (OR = 2.37, 95% confidence interval (CI): 1.07-5.53, p = 0.038). Significantly fewer patients from hg cluster JT received biological treatment (OR = 0.17, 95% CI: 0.03-0.87, p = 0.038). Albeit, none of these associations were significant when corrected for multiple tests. CONCLUSION There was no significant association between mtDNA hgs and presence of RA or disease manifestations. There was an, albeit insignificant, overrepresentation of patients with hg JT among patients with erosive disease; however, slightly fewer patients in the JT group were treated with biological drugs.
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Affiliation(s)
- Pernille Hurup Duhn
- Department of Rheumatology Frederiksberg Hospital, Nordre Fasanvej, Frederiksberg, Denmark
- * E-mail:
| | - Jacob Sode
- Department of Rheumatology Frederiksberg Hospital, Nordre Fasanvej, Frederiksberg, Denmark
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, Artillerivej, Copenhagen S, Denmark
- Institute of Regional Health Research, Center Sønderjylland, University of Southern Denmark, Campusvej, Odense M, Denmark
| | - Christian Munch Hagen
- Department for Congenital Disorders, Statens Serum Institut, Artillerivej, Copenhagen S, Denmark
| | - Michael Christiansen
- Department for Congenital Disorders, Statens Serum Institut, Artillerivej, Copenhagen S, Denmark
- Department of Biomedical Sciences, Faculty of Health and Life Science, University of Copenhagen, Blegdamsvej, Copenhagen N, Denmark
| | - Henning Locht
- Department of Rheumatology Frederiksberg Hospital, Nordre Fasanvej, Frederiksberg, Denmark
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Venter M, van der Westhuizen FH, Elson JL. The aetiology of cardiovascular disease: a role for mitochondrial DNA? Cardiovasc J Afr 2017; 29:122-132. [PMID: 28906532 PMCID: PMC6009096 DOI: 10.5830/cvja-2017-037] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 07/17/2017] [Indexed: 01/03/2023] Open
Abstract
Cardiovascular disease (CVD) is a world-wide cause of mortality in humans and its incidence is on the rise in Africa. In this review, we discuss the putative role of mitochondrial dysfunction in the aetiology of CVD and consequently identify mitochondrial DNA (mtDNA) variation as a viable genetic risk factor to be considered. We then describe the contribution and pitfalls of several current approaches used when investigating mtDNA in relation to complex disease. We also propose an alternative approach, the adjusted mutational load hypothesis, which would have greater statistical power with cohorts of moderate size, and is less likely to be affected by population stratification. We therefore address some of the shortcomings of the current haplogroup association approach. Finally, we discuss the unique challenges faced by studies done on African populations, and recommend the most viable methods to use when investigating mtDNA variation in CVD and other common complex disease.
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Affiliation(s)
- Marianne Venter
- Human Metabolomics, North-West University, Potchefstroom, South Africa.
| | | | - Joanna L Elson
- Human Metabolomics, North-West University, Potchefstroom, South Africa; Institute of Genetic Medicine, Newcastle University, United Kingdom
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12
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Heiske M, Letellier T, Klipp E. Comprehensive mathematical model of oxidative phosphorylation valid for physiological and pathological conditions. FEBS J 2017. [PMID: 28646582 DOI: 10.1111/febs.14151] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We developed a mathematical model of oxidative phosphorylation (OXPHOS) that allows for a precise description of mitochondrial function with respect to the respiratory flux and the ATP production. The model reproduced flux-force relationships under various experimental conditions (state 3 and 4, uncoupling, and shortage of respiratory substrate) as well as time courses, exhibiting correct P/O ratios. The model was able to reproduce experimental threshold curves for perturbations of the respiratory chain complexes, the F1 F0 -ATP synthase, the ADP/ATP carrier, the phosphate/OH carrier, and the proton leak. Thus, the model is well suited to study complex interactions within the OXPHOS system, especially with respect to physiological adaptations or pathological modifications, influencing substrate and product affinities or maximal catalytic rates. Moreover, it could be a useful tool to study the role of OXPHOS and its capacity to compensate or enhance physiopathologies of the mitochondrial and cellular energy metabolism.
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Affiliation(s)
- Margit Heiske
- Laboratoire d'Anthropologie Moléculaire et Imaginérie de Synthèse, Médecine Evolutive, UMR 5288 CNRS, Faculté de Médecine, Université de Toulouse, France.,Theoretische Biophysik, Institut für Biologie, Humboldt-Universität zu Berlin, Germany
| | - Thierry Letellier
- Laboratoire d'Anthropologie Moléculaire et Imaginérie de Synthèse, Médecine Evolutive, UMR 5288 CNRS, Faculté de Médecine, Université de Toulouse, France
| | - Edda Klipp
- Theoretische Biophysik, Institut für Biologie, Humboldt-Universität zu Berlin, Germany
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13
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Mitochondrial genotype modulates mtDNA copy number and organismal phenotype in Drosophila. Mitochondrion 2017; 34:75-83. [DOI: 10.1016/j.mito.2017.02.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 11/28/2016] [Accepted: 02/01/2017] [Indexed: 11/21/2022]
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14
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Gerencser AA, Mookerjee SA, Jastroch M, Brand MD. Positive Feedback Amplifies the Response of Mitochondrial Membrane Potential to Glucose Concentration in Clonal Pancreatic Beta Cells. Biochim Biophys Acta Mol Basis Dis 2016; 1863:1054-1065. [PMID: 27771512 DOI: 10.1016/j.bbadis.2016.10.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 10/16/2016] [Accepted: 10/18/2016] [Indexed: 02/07/2023]
Abstract
Analysis of the cellular mechanisms of metabolic disorders, including type 2 diabetes mellitus, is complicated by the large number of reactions and interactions in metabolic networks. Metabolic control analysis with appropriate modularization is a powerful method for simplifying and analyzing these networks. To analyze control of cellular energy metabolism in adherent cell cultures of the INS-1 832/13 pancreatic β-cell model we adapted our microscopy assay of absolute mitochondrial membrane potential (ΔψM) to a fluorescence microplate reader format, and applied it in conjunction with cell respirometry. In these cells the sensitive response of ΔψM to extracellular glucose concentration drives glucose-stimulated insulin secretion. Using metabolic control analysis we identified the control properties that generate this sensitive response. Force-flux relationships between ΔψM and respiration were used to calculate kinetic responses to ΔψM of processes both upstream (glucose oxidation) and downstream (proton leak and ATP turnover) of ΔψM. The analysis revealed that glucose-evoked ΔψM hyperpolarization is amplified by increased glucose oxidation activity caused by factors downstream of ΔψM. At high glucose, the hyperpolarized ΔψM is stabilized almost completely by the action of glucose oxidation, whereas proton leak also contributes to the homeostatic control of ΔψM at low glucose. These findings suggest a strong positive feedback loop in the regulation of β-cell energetics, and a possible regulatory role of proton leak in the fasting state. Analysis of islet bioenergetics from published cases of type 2 diabetes suggests that disruption of this feedback can explain the damaged bioenergetic response of β-cells to glucose. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.
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Affiliation(s)
- Akos A Gerencser
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States; Image Analyst Software, 43 Nova Lane, Novato, CA 94945, United States.
| | - Shona A Mookerjee
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States; Touro University California College of Pharmacy, 1310 Club Drive, Vallejo, CA 94592, United States
| | - Martin Jastroch
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States
| | - Martin D Brand
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States
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15
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Gnaiger E, Boushel R, Søndergaard H, Munch-Andersen T, Damsgaard R, Hagen C, Díez-Sánchez C, Ara I, Wright-Paradis C, Schrauwen P, Hesselink M, Calbet JAL, Christiansen M, Helge JW, Saltin B. Mitochondrial coupling and capacity of oxidative phosphorylation in skeletal muscle of Inuit and Caucasians in the arctic winter. Scand J Med Sci Sports 2016; 25 Suppl 4:126-34. [PMID: 26589126 DOI: 10.1111/sms.12612] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2015] [Indexed: 01/02/2023]
Abstract
During evolution, mitochondrial DNA haplogroups of arctic populations may have been selected for lower coupling of mitochondrial respiration to ATP production in favor of higher heat production. We show that mitochondrial coupling in skeletal muscle of traditional and westernized Inuit habituating northern Greenland is identical to Danes of western Europe haplogroups. Biochemical coupling efficiency was preserved across variations in diet, muscle fiber type, and uncoupling protein-3 content. Mitochondrial phenotype displayed plasticity in relation to lifestyle and environment. Untrained Inuit and Danes had identical capacities to oxidize fat substrate in arm muscle, which increased in Danes during the 42 days of acclimation to exercise, approaching the higher level of the Inuit hunters. A common pattern emerges of mitochondrial acclimatization and evolutionary adaptation in humans at high latitude and high altitude where economy of locomotion may be optimized by preservation of biochemical coupling efficiency at modest mitochondrial density, when submaximum performance is uncoupled from VO2max and maximum capacities of oxidative phosphorylation.
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Affiliation(s)
- E Gnaiger
- Department of Visceral, Transplant and Thoracic Surgery, D. Swarovski Research Laboratory, Medical University of Innsbruck, Innsbruck, Austria
| | - R Boushel
- The Copenhagen Muscle Research Centre, Copenhagen, Denmark.,School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - H Søndergaard
- The Copenhagen Muscle Research Centre, Copenhagen, Denmark
| | | | - R Damsgaard
- The Copenhagen Muscle Research Centre, Copenhagen, Denmark
| | - C Hagen
- National Serum Institute, Copenhagen, Denmark
| | - C Díez-Sánchez
- Department of Biochemistry and Molecular and Cell Biology, University of Zaragoza, Zaragoza, Spain
| | - I Ara
- GENUD Toledo Research Group, University of Castilla-La Mancha, Toledo, Spain
| | - C Wright-Paradis
- Department of Exercise Science, Concordia University, Montreal, QC, Canada
| | - P Schrauwen
- NUTRIM - School for Nutrition, Toxicology and Metabolism, Department of Human Biology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - M Hesselink
- NUTRIM - School for Nutrition, Toxicology and Metabolism, Department of Human Biology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - J A L Calbet
- Department of Physical Education, Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Las Palmas, Spain
| | | | - J W Helge
- The Copenhagen Muscle Research Centre, Copenhagen, Denmark.,X-Lab, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - B Saltin
- The Copenhagen Muscle Research Centre, Copenhagen, Denmark
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16
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Latorre-Pellicer A, Moreno-Loshuertos R, Lechuga-Vieco AV, Sánchez-Cabo F, Torroja C, Acín-Pérez R, Calvo E, Aix E, González-Guerra A, Logan A, Bernad-Miana ML, Romanos E, Cruz R, Cogliati S, Sobrino B, Carracedo Á, Pérez-Martos A, Fernández-Silva P, Ruíz-Cabello J, Murphy MP, Flores I, Vázquez J, Enríquez JA. Mitochondrial and nuclear DNA matching shapes metabolism and healthy ageing. Nature 2016; 535:561-5. [PMID: 27383793 DOI: 10.1038/nature18618] [Citation(s) in RCA: 265] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 06/02/2016] [Indexed: 12/25/2022]
Abstract
Human mitochondrial DNA (mtDNA) shows extensive within population sequence variability. Many studies suggest that mtDNA variants may be associated with ageing or diseases, although mechanistic evidence at the molecular level is lacking. Mitochondrial replacement has the potential to prevent transmission of disease-causing oocyte mtDNA. However, extension of this technology requires a comprehensive understanding of the physiological relevance of mtDNA sequence variability and its match with the nuclear-encoded mitochondrial genes. Studies in conplastic animals allow comparison of individuals with the same nuclear genome but different mtDNA variants, and have provided both supporting and refuting evidence that mtDNA variation influences organismal physiology. However, most of these studies did not confirm the conplastic status, focused on younger animals, and did not investigate the full range of physiological and phenotypic variability likely to be influenced by mitochondria. Here we systematically characterized conplastic mice throughout their lifespan using transcriptomic, proteomic,metabolomic, biochemical, physiological and phenotyping studies. We show that mtDNA haplotype profoundly influences mitochondrial proteostasis and reactive oxygen species generation,insulin signalling, obesity, and ageing parameters including telomere shortening and mitochondrial dysfunction, resulting in profound differences in health longevity between conplastic strains.
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17
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Diolez P, Bourdel-Marchasson I, Calmettes G, Pasdois P, Detaille D, Rouland R, Gouspillou G. Hypothesis on Skeletal Muscle Aging: Mitochondrial Adenine Nucleotide Translocator Decreases Reactive Oxygen Species Production While Preserving Coupling Efficiency. Front Physiol 2015; 6:369. [PMID: 26733871 PMCID: PMC4679911 DOI: 10.3389/fphys.2015.00369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 11/19/2015] [Indexed: 01/07/2023] Open
Abstract
Mitochondrial membrane potential is the major regulator of mitochondrial functions, including coupling efficiency and production of reactive oxygen species (ROS). Both functions are crucial for cell bioenergetics. We previously presented evidences for a specific modulation of adenine nucleotide translocase (ANT) appearing during aging that results in a decrease in membrane potential - and therefore ROS production-but surprisingly increases coupling efficiency under conditions of low ATP turnover. Careful study of the bioenergetic parameters (oxidation and phosphorylation rates, membrane potential) of isolated mitochondria from skeletal muscles (gastrocnemius) of aged and young rats revealed a remodeling at the level of the phosphorylation system, in the absence of alteration of the inner mitochondrial membrane (uncoupling) or respiratory chain complexes regulation. We further observed a decrease in mitochondrial affinity for ADP in aged isolated mitochondria, and higher sensitivity of ANT to its specific inhibitor atractyloside. This age-induced modification of ANT results in an increase in the ADP concentration required to sustain the same ATP turnover as compared to young muscle, and therefore in a lower membrane potential under phosphorylating-in vivo-conditions. Thus, for equivalent ATP turnover (cellular ATP demand), coupling efficiency is even higher in aged muscle mitochondria, due to the down-regulation of inner membrane proton leak caused by the decrease in membrane potential. In the framework of the radical theory of aging, these modifications in ANT function may be the result of oxidative damage caused by intra mitochondrial ROS and may appear like a virtuous circle where ROS induce a mechanism that reduces their production, without causing uncoupling, and even leading in improved efficiency. Because of the importance of ROS as therapeutic targets, this new mechanism deserves further studies.
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Affiliation(s)
- Philippe Diolez
- INSERM U1045 - Centre de Recherche Cardio-Thoracique de Bordeaux and LIRYC, Institut de Rythmologie et Modélisation Cardiaque, Université de Bordeaux, CHU de Bordeaux Pessac, France
| | - Isabelle Bourdel-Marchasson
- CHU de Bordeaux, Pôle de Gérontologie CliniqueBordeaux, France; Résonance Magnétique des Systèmes Biologiques, UMR 5536 Centre National de la Recherche Scientifique, Université de BordeauxBordeaux, France
| | - Guillaume Calmettes
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles Los Angeles, CA, USA
| | - Philippe Pasdois
- INSERM U1045 - Centre de Recherche Cardio-Thoracique de Bordeaux and LIRYC, Institut de Rythmologie et Modélisation Cardiaque, Université de Bordeaux, CHU de Bordeaux Pessac, France
| | - Dominique Detaille
- INSERM U1045 - Centre de Recherche Cardio-Thoracique de Bordeaux and LIRYC, Institut de Rythmologie et Modélisation Cardiaque, Université de Bordeaux, CHU de Bordeaux Pessac, France
| | - Richard Rouland
- Résonance Magnétique des Systèmes Biologiques, UMR 5536 Centre National de la Recherche Scientifique, Université de Bordeaux Bordeaux, France
| | - Gilles Gouspillou
- Département des Sciences de l'activité Physique, Université du Québec À Montréal Montréal, QC, Canada
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18
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Review: can diet influence the selective advantage of mitochondrial DNA haplotypes? Biosci Rep 2015; 35:BSR20150232. [PMID: 26543031 PMCID: PMC4708006 DOI: 10.1042/bsr20150232] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 11/05/2015] [Indexed: 01/12/2023] Open
Abstract
This review explores the potential for changes in dietary macronutrients to differentially influence mitochondrial bioenergetics and thereby the frequency of mtDNA haplotypes in natural populations. Such dietary modification may be seasonal or result from biogeographic or demographic shifts. Mechanistically, mtDNA haplotypes may influence the activity of the electron transport system (ETS), retrograde signalling to the nuclear genome and affect epigenetic modifications. Thus, differential provisioning by macronutrients may lead to selection through changes in the levels of ATP production, modulation of metabolites (including AMP, reactive oxygen species (ROS) and the NAD+/NADH ratio) and potentially complex epigenetic effects. The exquisite complexity of dietary influence on haplotype frequency is further illustrated by the fact that macronutrients may differentially influence the selective advantage of specific mutations in different life-history stages. In Drosophila, complex I mutations may affect larval growth because dietary nutrients are fed through this complex in immaturity. In contrast, the majority of electrons are provided to complex III in adult flies. We conclude the review with a case study that considers specific interactions between diet and complex I of the ETS. Complex I is the first enzyme of the mitochondrial ETS and co-ordinates in the oxidation of NADH and transfer of electrons to ubiquinone. Although the supposition that mtDNA variants may be selected upon by dietary macronutrients could be intuitively consistent to some and counter intuitive to others, it must face a multitude of scientific hurdles before it can be recognized.
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19
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Mitochondrial divergence between slow- and fast-aging garter snakes. Exp Gerontol 2015; 71:135-46. [PMID: 26403677 DOI: 10.1016/j.exger.2015.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 09/03/2015] [Accepted: 09/04/2015] [Indexed: 01/26/2023]
Abstract
Mitochondrial function has long been hypothesized to be intimately involved in aging processes--either directly through declining efficiency of mitochondrial respiration and ATP production with advancing age, or indirectly, e.g., through increased mitochondrial production of damaging free radicals with age. Yet we lack a comprehensive understanding of the evolution of mitochondrial genotypes and phenotypes across diverse animal models, particularly in species that have extremely labile physiology. Here, we measure mitochondrial genome-types and transcription in ecotypes of garter snakes (Thamnophis elegans) that are adapted to disparate habitats and have diverged in aging rates and lifespans despite residing in close proximity. Using two RNA-seq datasets, we (1) reconstruct the garter snake mitochondrial genome sequence and bioinformatically identify regulatory elements, (2) test for divergence of mitochondrial gene expression between the ecotypes and in response to heat stress, and (3) test for sequence divergence in mitochondrial protein-coding regions in these slow-aging (SA) and fast-aging (FA) naturally occurring ecotypes. At the nucleotide sequence level, we confirmed two (duplicated) mitochondrial control regions one of which contains a glucocorticoid response element (GRE). Gene expression of protein-coding genes was higher in FA snakes relative to SA snakes for most genes, but was neither affected by heat stress nor an interaction between heat stress and ecotype. SA and FA ecotypes had unique mitochondrial haplotypes with amino acid substitutions in both CYTB and ND5. The CYTB amino acid change (Isoleucine → Threonine) was highly segregated between ecotypes. This divergence of mitochondrial haplotypes between SA and FA snakes contrasts with nuclear gene-flow estimates, but correlates with previously reported divergence in mitochondrial function (mitochondrial oxygen consumption, ATP production, and reactive oxygen species consequences).
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20
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Hey-Mogensen M, Gram M, Jensen MB, Lund MT, Hansen CN, Scheibye-Knudsen M, Bohr VA, Dela F. A novel method for determining human ex vivo submaximal skeletal muscle mitochondrial function. J Physiol 2015; 593:3991-4010. [PMID: 26096709 DOI: 10.1113/jp270204] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 06/04/2015] [Indexed: 12/23/2022] Open
Abstract
The present study utilized a novel method aiming to investigate mitochondrial function in human skeletal muscle at submaximal levels and at a predefined membrane potential. The effect of age and training status was investigated using a cross-sectional design. Ageing was found to be related to decreased leak regardless of training status. Increased training status was associated with increased mitochondrial hydrogen peroxide emission. Despite numerous studies, there is no consensus about whether mitochondrial function is altered with increased age. The novelty of the present study is the determination of mitochondrial function at submaximal activity rates, which is more physiologically relevant than the ex vivo functionality protocols used previously. Muscle biopsies were taken from 64 old or young male subjects (aged 60-70 or 20-30 years). Aged subjects were recruited as trained or untrained. Muscle biopsies were used for the isolation of mitochondria and subsequent measurements of DNA repair, anti-oxidant capacity and mitochondrial protein levels (complexes I-V). Mitochondrial function was determined by simultaneous measurement of oxygen consumption, membrane potential and hydrogen peroxide emission using pyruvate + malate (PM) or succinate + rotenone (SR) as substrates. Proton leak was lower in aged subjects when determined at the same membrane potential and was unaffected by training status. State 3 respiration was lower in aged untrained subjects. This effect, however, was alleviated in aged trained subjects. H2 O2 emission with PM was higher in aged subjects, and was exacerbated by training, although it was not changed when using SR. However, with a higher manganese superoxide dismuthase content, the trained aged subjects may actually have lower or similar mitochondrial superoxide emission compared to the untrained subjects. We conclude that ageing and the physical activity level in aged subjects are both related to changes in the intrinsic functionality of the mitochondrion in skeletal muscle. Both of these changes could be important factors in determining the metabolic health of the aged skeletal muscle cell.
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Affiliation(s)
- Martin Hey-Mogensen
- Xlab, Center for Healthy Aging - Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.,Present address: Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Martin Gram
- Xlab, Center for Healthy Aging - Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Martin Borch Jensen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.,Present address: Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA, USA
| | - Michael Taulo Lund
- Xlab, Center for Healthy Aging - Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christina Neigaard Hansen
- Xlab, Center for Healthy Aging - Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Scheibye-Knudsen
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Vilhelm A Bohr
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.,Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Flemming Dela
- Xlab, Center for Healthy Aging - Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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21
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Pyle A, Hudson G, Wilson IJ, Coxhead J, Smertenko T, Herbert M, Santibanez-Koref M, Chinnery PF. Extreme-Depth Re-sequencing of Mitochondrial DNA Finds No Evidence of Paternal Transmission in Humans. PLoS Genet 2015; 11:e1005040. [PMID: 25973765 PMCID: PMC4431825 DOI: 10.1371/journal.pgen.1005040] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 01/28/2015] [Indexed: 11/18/2022] Open
Abstract
Recent reports have questioned the accepted dogma that mammalian mitochondrial DNA (mtDNA) is strictly maternally inherited. In humans, the argument hinges on detecting a signature of inter-molecular recombination in mtDNA sequences sampled at the population level, inferring a paternal source for the mixed haplotypes. However, interpreting these data is fraught with difficulty, and direct experimental evidence is lacking. Using extreme-high depth mtDNA re-sequencing up to ~1.2 million-fold coverage, we find no evidence that paternal mtDNA haplotypes are transmitted to offspring in humans, thus excluding a simple dilution mechanism for uniparental transmission of mtDNA present in all healthy individuals. Our findings indicate that an active mechanism eliminates paternal mtDNA which likely acts at the molecular level. Emerging evidence raises the possibility that human mitochondrial DNA (mtDNA) is not strictly maternally inherited, but it has not been technically possible to test this hypothesis directly. We identified trios with discordant mtDNA haplotypes, parent-offspring trios were validated using polymorphic microsatellites, and then used extreme-high depth mtDNA re-sequencing to look for paternally transmitted mtDNA. Despite having up to ~1.2 million-fold coverage of mtDNA, we find no evidence that paternal mtDNA haplotypes are transmitted to offspring in humans. Our findings exclude a simple dilution mechanism for uniparental transmission of mtDNA present in all healthy individuals.
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Affiliation(s)
- Angela Pyle
- Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle-upon-Tyne, United Kingdom
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Gavin Hudson
- Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle-upon-Tyne, United Kingdom
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Ian J. Wilson
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Jonathan Coxhead
- Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle-upon-Tyne, United Kingdom
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Tania Smertenko
- Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle-upon-Tyne, United Kingdom
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Mary Herbert
- Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle-upon-Tyne, United Kingdom
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Mauro Santibanez-Koref
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Patrick F. Chinnery
- Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle-upon-Tyne, United Kingdom
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
- * E-mail:
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22
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Garvin MR, Bielawski JP, Sazanov LA, Gharrett AJ. Review and meta-analysis of natural selection in mitochondrial complex I in metazoans. J ZOOL SYST EVOL RES 2014. [DOI: 10.1111/jzs.12079] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Michael R. Garvin
- Fisheries Division; School of Fisheries and Ocean Sciences; University of Alaska Fairbanks; Juneau AK USA
| | - Joseph P. Bielawski
- Department of Biology; Dalhousie University; Halifax NS Canada
- Department of Mathematics & Statistics; Dalhousie University; Halifax NS Canada
| | | | - Anthony J. Gharrett
- Fisheries Division; School of Fisheries and Ocean Sciences; University of Alaska Fairbanks; Juneau AK USA
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23
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Amo T, Saiki S, Sawayama T, Sato S, Hattori N. Detailed analysis of mitochondrial respiratory chain defects caused by loss of PINK1. Neurosci Lett 2014; 580:37-40. [PMID: 25092611 DOI: 10.1016/j.neulet.2014.07.045] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 07/10/2014] [Accepted: 07/25/2014] [Indexed: 11/26/2022]
Abstract
Mutations in PTEN-induced putative kinase 1 (PINK1) cause recessive forms of Parkinson's disease (PD). PINK1 acts upstream of parkin, regulating mitochondrial elimination (mitophagy) in cultured cells treated with mitochondrial uncouplers that cause mitochondrial depolarization. PINK1 loss-of-function decreases mitochondrial membrane potential, resulting in mitochondrial dysfunction, although the exact function of PINK1 in mitochondria has not been fully elucidated. We have previously found that PINK1 deficiency causes a decrease in mitochondrial membrane potential, which is not due to a proton leak, but to respiratory chain defects. Here, we examine mitochondrial respiratory chain defects in PINK1-deficient cells, and find both complex I and complex III are defective. These results suggest that mitochondrial respiratory chain defects may be associated with PD pathogenesis caused by mutations in the PINK1 gene.
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Affiliation(s)
- Taku Amo
- Department of Applied Chemistry, National Defense Academy, 1-10-20 Hashirimizu, Yokosuka 239-8686, Japan.
| | - Shinji Saiki
- Department of Neurology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Tadashi Sawayama
- Department of Applied Chemistry, National Defense Academy, 1-10-20 Hashirimizu, Yokosuka 239-8686, Japan
| | - Shigeto Sato
- Department of Neurology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Nobutaka Hattori
- Department of Neurology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
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24
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Gaweda-Walerych K, Zekanowski C. The impact of mitochondrial DNA and nuclear genes related to mitochondrial functioning on the risk of Parkinson's disease. Curr Genomics 2014; 14:543-59. [PMID: 24532986 PMCID: PMC3924249 DOI: 10.2174/1389202914666131210211033] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/30/2013] [Accepted: 08/29/2013] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial dysfunction and oxidative stress are the major factors implicated in Parkinson’s disease (PD)
pathogenesis. The maintenance of healthy mitochondria is a very complex process coordinated bi-genomically. Here, we
review association studies on mitochondrial haplogroups and subhaplogroups, discussing the underlying molecular
mechanisms. We also focus on variation in the nuclear genes (NDUFV2, PGC-1alpha, HSPA9, LRPPRC, MTIF3,
POLG1, and TFAM encoding NADH dehydrogenase (ubiquinone) flavoprotein 2, peroxisome proliferator-activated receptor
gamma coactivator 1-alpha, mortalin, leucine-rich pentatricopeptide repeat containing protein, translation initiation
factor 3, mitochondrial DNA polymerase gamma, and mitochondrial transcription factor A, respectively) primarily linked
to regulation of mitochondrial functioning that recently have been associated with PD risk. Possible interactions between
mitochondrial and nuclear genetic variants and related proteins are discussed.
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Affiliation(s)
- Katarzyna Gaweda-Walerych
- Laboratory of Neurogenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5 str., 02-106 Warszawa, Poland
| | - Cezary Zekanowski
- Laboratory of Neurogenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5 str., 02-106 Warszawa, Poland
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25
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Increased intrinsic mitochondrial function in humans with mitochondrial haplogroup H. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:226-31. [DOI: 10.1016/j.bbabio.2013.10.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 10/21/2013] [Accepted: 10/25/2013] [Indexed: 01/16/2023]
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26
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Dunham-Snary KJ, Ballinger SW. Mitochondrial genetics and obesity: evolutionary adaptation and contemporary disease susceptibility. Free Radic Biol Med 2013; 65:1229-1237. [PMID: 24075923 PMCID: PMC3859699 DOI: 10.1016/j.freeradbiomed.2013.09.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 09/12/2013] [Accepted: 09/13/2013] [Indexed: 12/22/2022]
Abstract
Obesity is a leading risk factor for a variety of metabolic diseases including cardiovascular disease, diabetes, and cancer. Although in its simplest terms, obesity may be thought of as a consequence of excessive caloric intake and sedentary lifestyle, it is also evident that individual propensity for weight gain can vary. The etiology of individual susceptibility to obesity seems to be complex-involving a combination of environmental-genetic interactions. Herein, we suggest that the mitochondrion plays a major role in influencing individual susceptibility to this disease via mitochondrial-nuclear interaction processes and that environmentally influenced selection events for mitochondrial function that conveyed increased reproductive and survival success during the global establishment of human populations during prehistoric times can influence individual susceptibility to weight gain and obesity.
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Affiliation(s)
- Kimberly J Dunham-Snary
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Scott W Ballinger
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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27
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Beyond retrograde and anterograde signalling: mitochondrial-nuclear interactions as a means for evolutionary adaptation and contemporary disease susceptibility. Biochem Soc Trans 2013; 41:111-7. [PMID: 23356268 DOI: 10.1042/bst20120227] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Although there is general agreement that most forms of common disease develop as a consequence of a combination of factors, including genetic, environmental and behavioural contributors, the actual mechanistic basis of how these factors initiate or promote diabetes, cancer, neurodegenerative and cardiovascular diseases in some individuals but not in others with seemingly identical risk factor profiles, is not clearly understood. In this respect, consideration of the potential role for mitochondrial genetics, damage and function in influencing common disease susceptibility seems merited, given that the prehistoric challenges were the original factors that moulded cellular function, and these were based upon the mitochondrial-nuclear relationships that were established during evolutionary history. These interactions were probably refined during prehistoric environmental selection events that, at present, are largely absent. Contemporary risk factors such as diet, sedentary lifestyle and increased longevity, which influence our susceptibility to a variety of chronic diseases were not part of the dynamics that defined the processes of mitochondrial-nuclear interaction, and thus cell function. Consequently, the prehistoric challenges that contributed to cell functionality and evolution should be considered when interpreting and designing experimental data and strategies. Although several molecular epidemiological studies have generally supported this notion, studies that probe beyond these associations are required. Such investigation will mark the initial steps for mechanistically addressing the provocative concept that contemporary human disease susceptibility is the result of prehistoric selection events for mitochondrial-nuclear function, which increased the probability for survival and reproductive success during evolution.
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28
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Abstract
Mutations in the human mitochondrial genome are known to cause an array of diverse disorders, most of which are maternally inherited, and all of which are associated with defects in oxidative energy metabolism. It is now emerging that somatic mutations in mitochondrial DNA (mtDNA) are also linked to other complex traits, including neurodegenerative diseases, ageing and cancer. Here we discuss insights into the roles of mtDNA mutations in a wide variety of diseases, highlighting the interesting genetic characteristics of the mitochondrial genome and challenges in studying its contribution to pathogenesis.
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29
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Hill BG, Benavides GA, Lancaster JR, Ballinger S, Dell’Italia L, Zhang J, Darley-Usmar VM. Integration of cellular bioenergetics with mitochondrial quality control and autophagy. Biol Chem 2012; 393:1485-1512. [PMID: 23092819 PMCID: PMC3594552 DOI: 10.1515/hsz-2012-0198] [Citation(s) in RCA: 330] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Accepted: 06/22/2012] [Indexed: 02/06/2023]
Abstract
Bioenergetic dysfunction is emerging as a cornerstone for establishing a framework for understanding the pathophysiology of cardiovascular disease, diabetes,cancer and neurodegeneration. Recent advances in cellular bioenergetics have shown that many cells maintain a substantial bioenergetic reserve capacity, which is a prospective index of ‘ healthy ’ mitochondrial populations.The bioenergetics of the cell are likely regulated by energy requirements and substrate availability. Additionally,the overall quality of the mitochondrial population and the relative abundance of mitochondria in cells and tissues also impinge on overall bioenergetic capacity and resistance to stress. Because mitochondria are susceptible to damage mediated by reactive oxygen/nitrogen and lipid species, maintaining a ‘ healthy ’ population of mitochondria through quality control mechanisms appears to be essential for cell survival under conditions of pathological stress. Accumulating evidence suggest that mitophagy is particularly important for preventing amplification of initial oxidative insults, which otherwise would further impair the respiratory chain or promote mutations in mitochondrial DNA (mtDNA). The processes underlying the regulation of mitophagy depend on several factors, including the integrity of mtDNA, electron transport chain activity, and the interaction and regulation of the autophagic machinery. The integration and interpretation of cellular bioenergetics in the context of mitochondrial quality control and genetics is the theme of this review.
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Affiliation(s)
- Bradford G. Hill
- Diabetes and Obesity Center, Institute of Molecular Cardiology, and Department of Medicine, University of Louisville, Louisville, KY
- Departments of Biochemistry and Molecular Biology and Physiology and Biophysics, University of Louisville, Louisville, KY
| | - Gloria A. Benavides
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Jack R. Lancaster
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Scott Ballinger
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Medicine, Center for Heart Failure Research, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Lou Dell’Italia
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Medicine, Center for Heart Failure Research, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Veteran Affairs Medical Center, Birmingham, AL 35294
| | - Jianhua Zhang
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Veteran Affairs Medical Center, Birmingham, AL 35294
| | - Victor M. Darley-Usmar
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294
- Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Medicine, Center for Heart Failure Research, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Environmental Health Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
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Mitochondrial DNA variants influence mitochondrial bioenergetics in Drosophila melanogaster. Mitochondrion 2012; 12:459-64. [DOI: 10.1016/j.mito.2012.06.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 06/12/2012] [Accepted: 06/19/2012] [Indexed: 11/21/2022]
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Pichaud N, Ballard JWO, Tanguay RM, Blier PU. Naturally occurring mitochondrial DNA haplotypes exhibit metabolic differences: insight into functional properties of mitochondria. Evolution 2012; 66:3189-97. [PMID: 23025608 DOI: 10.1111/j.1558-5646.2012.01683.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Linking the mitochondrial genotype and the organismal phenotype is of paramount importance in evolution of mitochondria. In this study, we determined the differences in catalytic properties of mitochondria dictated by divergences in the siII and siIII haplogroups of Drosophila simulans using introgressions of siII mtDNA type into the siIII nuclear background. We used a novel in situ method (permeabilized fibers) that allowed us to accurately measure the consumption of oxygen by mitochondria in constructed siII-introgressed flies and in siIII-control flies. Our results showed that the catalytic capacity of the electron transport system is not impaired by introgressions, suggesting that the functional properties of mitochondria are tightly related to the mtDNA haplogroup and not to the nuclear DNA or to the mito-nuclear interactions. This is the first study, to our knowledge, that demonstrates a naturally occurring haplogroup can confer specific functional differences in aspects of mitochondrial metabolism. This study illustrates the importance of mtDNA changes on organelle evolution and highlights the potential bioenergetic and metabolic impacts that divergent mitochondrial haplogroups may have upon a wide variety of species including humans.
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Affiliation(s)
- Nicolas Pichaud
- Laboratoire de biologie intégrative, Département de Biologie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, Québec, Canada G5L 3A1.
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32
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Abstract
Modularization is an important strategy to tackle the study of complex biological systems. Modular kinetic analysis (MKA) is a quantitative method to extract kinetic information from such a modularized system that can be used to determine the control and regulatory structure of the system, and to pinpoint and quantify the interaction of effectors with the system. The principles of the method are described, and the relation with metabolic control analysis is discussed. Examples of application of MKA are given.
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Glanville EJ, Murray SA, Seebacher F. Thermal adaptation in endotherms: climate and phylogeny interact to determine population-level responses in a wild rat. Funct Ecol 2011. [DOI: 10.1111/j.1365-2435.2011.01933.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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34
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Garvin MR, Bielawski JP, Gharrett AJ. Positive Darwinian selection in the piston that powers proton pumps in complex I of the mitochondria of Pacific salmon. PLoS One 2011; 6:e24127. [PMID: 21969854 PMCID: PMC3182164 DOI: 10.1371/journal.pone.0024127] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 08/04/2011] [Indexed: 11/23/2022] Open
Abstract
The mechanism of oxidative phosphorylation is well understood, but evolution of the proteins involved is not. We combined phylogenetic, genomic, and structural biology analyses to examine the evolution of twelve mitochondrial encoded proteins of closely related, yet phenotypically diverse, Pacific salmon. Two separate analyses identified the same seven positively selected sites in ND5. A strong signal was also detected at three sites of ND2. An energetic coupling analysis revealed several structures in the ND5 protein that may have co-evolved with the selected sites. These data implicate Complex I, specifically the piston arm of ND5 where it connects the proton pumps, as important in the evolution of Pacific salmon. Lastly, the lineage to Chinook experienced rapid evolution at the piston arm.
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Affiliation(s)
- Michael R Garvin
- Fisheries Division, School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska, United States of America.
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35
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Abstract
Assessing mitochondrial dysfunction requires definition of the dysfunction to be investigated. Usually, it is the ability of the mitochondria to make ATP appropriately in response to energy demands. Where other functions are of interest, tailored solutions are required. Dysfunction can be assessed in isolated mitochondria, in cells or in vivo, with different balances between precise experimental control and physiological relevance. There are many methods to measure mitochondrial function and dysfunction in these systems. Generally, measurements of fluxes give more information about the ability to make ATP than do measurements of intermediates and potentials. For isolated mitochondria, the best assay is mitochondrial respiratory control: the increase in respiration rate in response to ADP. For intact cells, the best assay is the equivalent measurement of cell respiratory control, which reports the rate of ATP production, the proton leak rate, the coupling efficiency, the maximum respiratory rate, the respiratory control ratio and the spare respiratory capacity. Measurements of membrane potential provide useful additional information. Measurement of both respiration and potential during appropriate titrations enables the identification of the primary sites of effectors and the distribution of control, allowing deeper quantitative analyses. Many other measurements in current use can be more problematic, as discussed in the present review.
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36
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Mitochondrial DNA variants in Drosophila melanogaster are expressed at the level of the organismal phenotype. Mitochondrion 2011; 11:756-63. [DOI: 10.1016/j.mito.2011.06.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 05/30/2011] [Accepted: 06/28/2011] [Indexed: 11/24/2022]
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Fridlyand LE, Phillipson LH. Mechanisms of glucose sensing in the pancreatic β-cell: A computational systems-based analysis. Islets 2011; 3:224-30. [PMID: 21814042 PMCID: PMC3219158 DOI: 10.4161/isl.3.5.16409] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Pancreatic β-cells respond to rising blood glucose by increasing oxidative metabolism, leading to an increased ATP/ADP ratio in the cytoplasm with a subsequent influx of calcium and the eventual secretion of insulin. The mechanisms of glucose sensing in the pancreatic β-cell involve the coupling of cytoplasmic and mitochondrial processes. Our analysis, based on mathematical models of data from multiple sources has implications for β-cell function and the treatment of type 2 diabetes (Fridlyand and Philipson, 2010). This β-cell glucose response model correctly predicts changes in the ATP/ADP ratio, cytoplasmic and mitochondrial calcium levels, and other metabolic parameters in response to alterations in substrate delivery at steady-state and during cytoplasmic calcium oscillations. Here we consider how peculiarities of β-cell pathways that result in dysfunction can be a consequence of specific mechanisms of glucose sensitivity, using our computational systems-based analysis. We found that the mitochondrial membrane potential must be relatively low in β-cells compared with other cell types to permit precise mitochondrial regulation of the cytoplasmic ATP/ADP ratio. This key difference may follow from a relative reduction in cellular respiratory activity. Our analysis additionally demonstrates how activity of lactate dehydrogenase, uncoupling proteins, and the redox shuttles all working in concert can regulate β-cell function. We further show that a decreased mitochondrial membrane potential may lead to a low rate of production of reactive oxygen species in β-cells under physiological conditions. This computational systems analysis aids in providing a more complete understanding of the complex process of β-cell glucose sensing.
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38
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Krzywanski DM, Moellering DR, Fetterman JL, Dunham-Snary KJ, Sammy MJ, Ballinger SW. The mitochondrial paradigm for cardiovascular disease susceptibility and cellular function: a complementary concept to Mendelian genetics. J Transl Med 2011; 91:1122-35. [PMID: 21647091 PMCID: PMC3654682 DOI: 10.1038/labinvest.2011.95] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
While there is general agreement that cardiovascular disease (CVD) development is influenced by a combination of genetic, environmental, and behavioral contributors, the actual mechanistic basis of how these factors initiate or promote CVD development in some individuals while others with identical risk profiles do not, is not clearly understood. This review considers the potential role for mitochondrial genetics and function in determining CVD susceptibility from the standpoint that the original features that molded cellular function were based upon mitochondrial-nuclear relationships established millions of years ago and were likely refined during prehistoric environmental selection events that today, are largely absent. Consequently, contemporary risk factors that influence our susceptibility to a variety of age-related diseases, including CVD were probably not part of the dynamics that defined the processes of mitochondrial-nuclear interaction, and thus, cell function. In this regard, the selective conditions that contributed to cellular functionality and evolution should be given more consideration when interpreting and designing experimental data and strategies. Finally, future studies that probe beyond epidemiologic associations are required. These studies will serve as the initial steps for addressing the provocative concept that contemporary human disease susceptibility is the result of selection events for mitochondrial function that increased chances for prehistoric human survival and reproductive success.
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Affiliation(s)
- David M Krzywanski
- Division of Molecular and Cellular Pathology, Department of Pathology, The University of Alabama at Birmingham, Birmingham, AL, USA
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39
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Gouspillou G, Rouland R, Calmettes G, Deschodt-Arsac V, Franconi JM, Bourdel-Marchasson I, Diolez P. Accurate determination of the oxidative phosphorylation affinity for ADP in isolated mitochondria. PLoS One 2011; 6:e20709. [PMID: 21694779 PMCID: PMC3111431 DOI: 10.1371/journal.pone.0020709] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 05/09/2011] [Indexed: 11/19/2022] Open
Abstract
Background Mitochondrial dysfunctions appear strongly implicated in a wide range of pathologies. Therefore, there is a growing need in the determination of the normal and pathological integrated response of oxidative phosphorylation to cellular ATP demand. The present study intends to address this issue by providing a method to investigate mitochondrial oxidative phosphorylation affinity for ADP in isolated mitochondria. Methodology/Principal Findings The proposed method is based on the simultaneous monitoring of substrate oxidation (determined polarographically) and phosphorylation (determined using the glucose - hexokinase - glucose-6-phosphate dehydrogenase - NADP+ enzymatic system) rates, coupled to the determination of actual ADP and ATP concentrations by bioluminescent assay. This enzymatic system allows the study of oxidative phosphorylation during true steady states in a wide range of ADP concentrations. We demonstrate how the application of this method allows an accurate determination of mitochondrial affinity for ADP from both oxidation (KmVox) and phosphorylation (KmVp) rates. We also demonstrate that determination of KmVox leads to an important overestimation of the mitochondrial affinity for ADP, indicating that mitochondrial affinity for ADP should be determined using phosphorylation rate. Finally, we show how this method allows the direct and precise determination of the mitochondrial coupling efficiency. Data obtained from rat skeletal muscle and liver mitochondria illustrate the discriminating capabilities of this method. Conclusions/Significance Because the proposed method allows the accurate determination of mitochondrial oxidative phosphorylation affinity for ADP in isolated mitochondria, it also opens the route to a better understanding of functional consequences of mitochondrial adaptations/dysfunctions arising in various physiological/pathophysiological conditions.
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Affiliation(s)
- Gilles Gouspillou
- Laboratoire de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS - Université Victor Segalen Bordeaux 2, Bordeaux, France
- * E-mail: (PD); (GG)
| | - Richard Rouland
- Laboratoire de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS - Université Victor Segalen Bordeaux 2, Bordeaux, France
| | - Guillaume Calmettes
- Laboratoire de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS - Université Victor Segalen Bordeaux 2, Bordeaux, France
| | - Véronique Deschodt-Arsac
- Laboratoire de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS - Université Victor Segalen Bordeaux 2, Bordeaux, France
| | - Jean-Michel Franconi
- Laboratoire de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS - Université Victor Segalen Bordeaux 2, Bordeaux, France
| | - Isabelle Bourdel-Marchasson
- Laboratoire de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS - Université Victor Segalen Bordeaux 2, Bordeaux, France
- CHU de Bordeaux - Pôle de gérontologie clinique, Hôpital Xavier Arnozan, Pessac, France
| | - Philippe Diolez
- Laboratoire de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS - Université Victor Segalen Bordeaux 2, Bordeaux, France
- * E-mail: (PD); (GG)
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40
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Tranah GJ, Manini TM, Lohman KK, Nalls MA, Kritchevsky S, Newman AB, Harris TB, Miljkovic I, Biffi A, Cummings SR, Liu Y. Mitochondrial DNA variation in human metabolic rate and energy expenditure. Mitochondrion 2011; 11:855-61. [PMID: 21586348 DOI: 10.1016/j.mito.2011.04.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 03/25/2011] [Accepted: 04/29/2011] [Indexed: 01/18/2023]
Abstract
The role of climate in driving selection of mtDNA as Homo sapiens migrated out of Africa into Eurasia remains controversial. We evaluated the role of mtDNA variation in resting metabolic rate (RMR) and total energy expenditure (TEE) among 294 older, community-dwelling African and European American adults from the Health, Aging and Body Composition Study. Common African haplogroups L0, L2 and L3 had significantly lower RMRs than European haplogroups H, JT and UK with haplogroup L1 RMR being intermediate to these groups. This study links mitochondrial haplogroups with ancestry-associated differences in metabolic rate and energy expenditure.
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Affiliation(s)
- Gregory J Tranah
- California Pacific Medical Center Research Institute, San Francisco, CA, 94107, USA.
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41
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Pereira L, Soares P, Radivojac P, Li B, Samuels D. Comparing phylogeny and the predicted pathogenicity of protein variations reveals equal purifying selection across the global human mtDNA diversity. Am J Hum Genet 2011; 88:433-9. [PMID: 21457906 DOI: 10.1016/j.ajhg.2011.03.006] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 03/01/2011] [Accepted: 03/08/2011] [Indexed: 02/06/2023] Open
Abstract
We used detailed phylogenetic trees for human mtDNA, combined with pathogenicity predictions for each amino acid change, to evaluate selection on mtDNA-encoded protein variants. Protein variants with high pathogenicity scores were significantly rarer in the older branches of the tree. Variants that have formed and survived multiple times in the human phylogenetics tree had significantly lower pathogenicity scores than those that only appear once in the tree. We compared the distribution of pathogenicity scores observed on the human phylogenetic tree to the distribution of all possible protein variations to define a measure of the effect of selection on these protein variations. The measured effect of selection increased exponentially with increasing pathogenicity score. We found no measurable difference in this measure of purifying selection in mtDNA across the global population, represented by the macrohaplogroups L, M, and N. We provide a list of all possible single amino acid variations for the human mtDNA-encoded proteins with their predicted pathogenicity scores and our measured selection effect as a tool for assessing novel protein variations that are often reported in patients with mitochondrial disease of unknown origin or for assessing somatic mutations acquired through aging or detected in tumors.
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42
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Tranah GJ. Mitochondrial-nuclear epistasis: implications for human aging and longevity. Ageing Res Rev 2011; 10:238-52. [PMID: 20601194 DOI: 10.1016/j.arr.2010.06.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 06/17/2010] [Accepted: 06/17/2010] [Indexed: 12/22/2022]
Abstract
There is substantial evidence that mitochondria are involved in the aging process. Mitochondrial function requires the coordinated expression of hundreds of nuclear genes and a few dozen mitochondrial genes, many of which have been associated with either extended or shortened life span. Impaired mitochondrial function resulting from mtDNA and nuclear DNA variation is likely to contribute to an imbalance in cellular energy homeostasis, increased vulnerability to oxidative stress, and an increased rate of cellular senescence and aging. The complex genetic architecture of mitochondria suggests that there may be an equally complex set of gene interactions (epistases) involving genetic variation in the nuclear and mitochondrial genomes. Results from Drosophila suggest that the effects of mtDNA haplotypes on longevity vary among different nuclear allelic backgrounds, which could account for the inconsistent associations that have been observed between mitochondrial DNA (mtDNA) haplogroups and survival in humans. A diversity of pathways may influence the way mitochondria and nuclear-mitochondrial interactions modulate longevity, including: oxidative phosphorylation; mitochondrial uncoupling; antioxidant defenses; mitochondrial fission and fusion; and sirtuin regulation of mitochondrial genes. We hypothesize that aging and longevity, as complex traits having a significant genetic component, are likely to be controlled by nuclear gene variants interacting with both inherited and somatic mtDNA variability.
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Toyomizu M, Kikusato M, Kawabata Y, Azad MAK, Inui E, Amo T. Meat-type chickens have a higher efficiency of mitochondrial oxidative phosphorylation than laying-type chickens. Comp Biochem Physiol A Mol Integr Physiol 2011; 159:75-81. [PMID: 21300168 DOI: 10.1016/j.cbpa.2011.01.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 01/17/2011] [Accepted: 01/29/2011] [Indexed: 11/29/2022]
Abstract
Meat-type chickens show high feed efficiency and have a very rapid growth rate compared with laying-type chickens. To clarify whether the type-specific difference in feed conversion efficiency is involved in mitochondrial bioenergetics, modular kinetic analysis was applied to oxidative phosphorylation in skeletal muscle mitochondria of both type chickens. Mitochondria from skeletal muscle of meat-type chickens showed greater substrate oxidation and phosphorylating activities, and less proton leak than those of the laying-type, resulting in a higher efficiency of oxidative phosphorylation. Gene expression and protein content of uncoupling protein (avUCP) but not adenine nucleotide translocase (avANT) gene expression were lower in skeletal muscle mitochondria of meat-type chickens than the laying-type. The current results regarding a higher efficiency of oxidative phosphorylation and UCP content may partially support the high feed efficiency of meat-type chickens.
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Affiliation(s)
- Masaaki Toyomizu
- Science of Biological Function, Life Science, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
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44
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Seebacher F, Brand MD, Else PL, Guderley H, Hulbert AJ, Moyes CD. Plasticity of oxidative metabolism in variable climates: molecular mechanisms. Physiol Biochem Zool 2010; 83:721-32. [PMID: 20586603 DOI: 10.1086/649964] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Converting food to chemical energy (ATP) that is usable by cells is a principal requirement to sustain life. The rate of ATP production has to be sufficient for housekeeping functions, such as protein synthesis and maintaining membrane potentials, as well as for growth and locomotion. Energy metabolism is temperature sensitive, and animals respond to environmental variability at different temporal levels, from within-individual to evolutionary timescales. Here we review principal molecular mechanisms that underlie control of oxidative ATP production in response to climate variability. Nuclear transcription factors and coactivators control expression of mitochondrial proteins and abundance of mitochondria. Fatty acid and phospholipid concentrations of membranes influence the activity of membrane-bound proteins as well as the passive leak of protons across the mitochondrial membrane. Passive proton leak as well as protein-mediated proton leak across the inner mitochondrial membrane determine the efficacy of ATP production but are also instrumental in endothermic heat production and as a defense against reactive oxygen species. Both transcriptional mechanisms and membrane composition interact with environmental temperature and diet, and this interaction between diet and temperature in determining mitochondrial function links the two major environmental variables that are affected by changing climates. The limits to metabolic plasticity could be set by the production of reactive oxygen species leading to cellular damage, limits to substrate availability in mitochondria, and a disproportionally large increase in proton leak over ATP production.
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Affiliation(s)
- Frank Seebacher
- School of Biological Sciences, University of Sydney, Sydney, New South Wales 2006, Australia.
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45
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Zsurka G, Kudina T, Peeva V, Hallmann K, Elger CE, Khrapko K, Kunz WS. Distinct patterns of mitochondrial genome diversity in bonobos (Pan paniscus) and humans. BMC Evol Biol 2010; 10:270. [PMID: 20813043 PMCID: PMC2942848 DOI: 10.1186/1471-2148-10-270] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 09/02/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND We have analyzed the complete mitochondrial genomes of 22 Pan paniscus (bonobo, pygmy chimpanzee) individuals to assess the detailed mitochondrial DNA (mtDNA) phylogeny of this close relative of Homo sapiens. RESULTS We identified three major clades among bonobos that separated approximately 540,000 years ago, as suggested by Bayesian analysis. Incidentally, we discovered that the current reference sequence for bonobo likely is a hybrid of the mitochondrial genomes of two distant individuals. When comparing spectra of polymorphic mtDNA sites in bonobos and humans, we observed two major differences: (i) Of all 31 bonobo mtDNA homoplasies, i.e. nucleotide changes that occurred independently on separate branches of the phylogenetic tree, 13 were not homoplasic in humans. This indicates that at least a part of the unstable sites of the mitochondrial genome is species-specific and difficult to be explained on the basis of a mutational hotspot concept. (ii) A comparison of the ratios of non-synonymous to synonymous changes (dN/dS) among polymorphic positions in bonobos and in 4902 Homo sapiens mitochondrial genomes revealed a remarkable difference in the strength of purifying selection in the mitochondrial genes of the F0F1-ATPase complex. While in bonobos this complex showed a similar low value as complexes I and IV, human haplogroups displayed 2.2 to 7.6 times increased dN/dS ratios when compared to bonobos. CONCLUSIONS Some variants of mitochondrially encoded subunits of the ATPase complex in humans very likely decrease the efficiency of energy conversion leading to production of extra heat. Thus, we hypothesize that the species-specific release of evolutionary constraints for the mitochondrial genes of the proton-translocating ATPase is a consequence of altered heat homeostasis in modern humans.
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Affiliation(s)
- Gábor Zsurka
- Division of Neurochemistry, Department of Epileptology and Life&Brain Center, University Bonn, Sigmund-Freud-Str. 25, 53105 Bonn, Germany
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Application of modular kinetic analysis to mitochondrial oxidative phosphorylation in skeletal muscle of birds exposed to acute heat stress. FEBS Lett 2010; 584:3143-8. [DOI: 10.1016/j.febslet.2010.05.057] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 05/26/2010] [Indexed: 12/21/2022]
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47
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Fridlyand LE, Philipson LH. Glucose sensing in the pancreatic beta cell: a computational systems analysis. Theor Biol Med Model 2010; 7:15. [PMID: 20497556 PMCID: PMC2896931 DOI: 10.1186/1742-4682-7-15] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Accepted: 05/24/2010] [Indexed: 12/29/2022] Open
Abstract
Background Pancreatic beta-cells respond to rising blood glucose by increasing oxidative metabolism, leading to an increased ATP/ADP ratio in the cytoplasm. This leads to a closure of KATP channels, depolarization of the plasma membrane, influx of calcium and the eventual secretion of insulin. Such mechanism suggests that beta-cell metabolism should have a functional regulation specific to secretion, as opposed to coupling to contraction. The goal of this work is to uncover contributions of the cytoplasmic and mitochondrial processes in this secretory coupling mechanism using mathematical modeling in a systems biology approach. Methods We describe a mathematical model of beta-cell sensitivity to glucose. The cytoplasmic part of the model includes equations describing glucokinase, glycolysis, pyruvate reduction, NADH and ATP production and consumption. The mitochondrial part begins with production of NADH, which is regulated by pyruvate dehydrogenase. NADH is used in the electron transport chain to establish a proton motive force, driving the F1F0 ATPase. Redox shuttles and mitochondrial Ca2+ handling were also modeled. Results The model correctly predicts changes in the ATP/ADP ratio, Ca2+ and other metabolic parameters in response to changes in substrate delivery at steady-state and during cytoplasmic Ca2+ oscillations. Our analysis of the model simulations suggests that the mitochondrial membrane potential should be relatively lower in beta cells compared with other cell types to permit precise mitochondrial regulation of the cytoplasmic ATP/ADP ratio. This key difference may follow from a relative reduction in respiratory activity. The model demonstrates how activity of lactate dehydrogenase, uncoupling proteins and the redox shuttles can regulate beta-cell function in concert; that independent oscillations of cytoplasmic Ca2+ can lead to slow coupled metabolic oscillations; and that the relatively low production rate of reactive oxygen species in beta-cells under physiological conditions is a consequence of the relatively decreased mitochondrial membrane potential. Conclusion This comprehensive model predicts a special role for mitochondrial control mechanisms in insulin secretion and ROS generation in the beta cell. The model can be used for testing and generating control hypotheses and will help to provide a more complete understanding of beta-cell glucose-sensing central to the physiology and pathology of pancreatic β-cells.
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Affiliation(s)
- Leonid E Fridlyand
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA.
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Gouspillou G, Bourdel-Marchasson I, Rouland R, Calmettes G, Franconi JM, Deschodt-Arsac V, Diolez P. Alteration of mitochondrial oxidative phosphorylation in aged skeletal muscle involves modification of adenine nucleotide translocator. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:143-51. [PMID: 19751701 DOI: 10.1016/j.bbabio.2009.09.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 09/04/2009] [Accepted: 09/09/2009] [Indexed: 01/07/2023]
Abstract
The process of skeletal muscle aging is characterized by a progressive loss of muscle mass and functionality. The underlying mechanisms are highly complex and remain unclear. This study was designed to further investigate the consequences of aging on mitochondrial oxidative phosphorylation in rat gastrocnemius muscle, by comparing young (6 months) and aged (21 months) rats. Maximal oxidative phosphorylation capacity was clearly reduced in older rats, while mitochondrial efficiency was unaffected. Inner membrane properties were unaffected in aged rats since proton leak kinetics were identical to young rats. Application of top-down control analysis revealed a dysfunction of the phosphorylation module in older rats, responsible for a dysregulation of oxidative phosphorylation under low activities close to in vivo ATP turnover. This dysregulation is responsible for an impaired mitochondrial response toward changes in cellular ATP demand, leading to a decreased membrane potential which may in turn affect ROS production and ion homeostasis. Based on our data, we propose that modification of ANT properties with aging could partly explain these mitochondrial dysfunctions.
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Affiliation(s)
- Gilles Gouspillou
- Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS-Université Victor Segalen Bordeaux 2, 146 Rue Léo Saignat, 33076 Bordeaux Cedex, France
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